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The aims of this research were to evaluate how prolonged feeding of a high-concentrate diet affects the ruminal degradation kinetics of fiber and starch, and to evaluate the effects of the high-concentrate diet on apparent total-tract nutrient digestibility in dairy cows. We also investigated the dysbiotic effects and the remodeling of the hindgut microbiome with prolonged high-concentrate feeding. Nine Holstein cows were used in 2 experimental periods; in each period, cows were first fed a 100% forage diet for 1 wk, followed by stepwise adaptation during one week to a high-concentrate (HC) diet (65% concentrate), which was then fed for 4 consecutive weeks. The kinetics of in situ ruminal degradability of grass silage (DM and NDF), corn grain and wheat grain (DM and starch), as well as the apparent total-tract nutrient digestibility were evaluated in the forage feeding and in wk 4 on the HC diet. Whereas the hindgut microbiome and fermentation profile were evaluated on a weekly basis. Regarding the in situ ruminal degradability due to grain type, the rate of degradation of the potentially degradable fraction and the effective rumen degradability of wheat grain were greater compared with corn grain. The in situ ruminal degradability of NDF decreased with the HC diet. However, the apparent total-tract digestibility of CP, fat, starch, NDF, ADF, and NFC increased with the HC diet compared with forage feeding. In addition, the HC diet increased the concentration of short-chain fatty acids in the hindgut, lowering fecal pH by 0.6 units, which correlated positively with microbial α diversity. This resulted in lower α diversity with the HC diet; however, α diversity (number of amplicon sequence variants) showed recovery in wk 3 and 4 on HC; in addition, microbial β diversity did not change from wk 2 onward on the HC diet. Two microbial enterotypes were identified: one for the forage diet with abundance of Akkermansia and Anaerosporobacter , and another enterotype for the HC diet with enrichment in Bifidobacterium and Butyrivibrio. Overall, results show that major microbial shifts and hindgut dysbiosis occurred in wk 1 on the HC diet. However, the hindgut microbial diversity of cows adapted after 3 wk of consuming the starch-rich ration. Thus, feeding the HC diet impaired fiber degradation in the rumen, but increased apparent total-tract nutrient digestibility. Likely, the forage diet contained less digestible NDF than the HC diet due to greater inclusion of forages with lower NDF digestibility and lower inclusion of more digestible nonforage NDF. Results also suggest that the adaptation of the hindgut microbial diversity of cows observed 3 weeks after the diet transition likely contributed to enhance total-tract nutrient digestibility. The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. [ABSTRACT FROM AUTHOR]

Tailocins, phage tail-like bacteriocins, are bacterial protein complexes that kill neighboring bacteria, thereby suppressing competitors. The specificity of tailocins depends on their tail fibers, which bind to the target cell's outer membrane, especially binding to specific lipopolysaccharide (LPS) components in a lock-and-key manner. This LPS binding defines the range of bacteria that tailocins can kill. Tailocin genomic loci exhibit differential rates of evolution, with conserved genes involved in structural components and variable genes, such as the tail fibers, determining specificity. The maintenance of diverse tailocin variants over time is likely driven by balancing selection, contributing to long-term persistence within bacterial populations. A tradeoff exists between evolving resistance to tailocins and colonizing the host. Tailocin specificity can be easily modified by swapping tail fibers. Phage tail-like bacteriocins (tailocins) are protein complexes produced by bacteria with the potential to kill their neighbors. Widespread throughout Gram-negative bacteria, tailocins exhibit extreme specificity in their targets, largely killing closely related strains. Despite their presence in diverse bacteria, the impact of these competitive weapons on the surrounding microbiota is largely unknown. Recent studies revealed the rapid evolution and genetic diversity of tailocins in microbial communities and suggest that there are constraints on the evolution of specificity and resistance. Given the precision of their targeted killing and the ease of engineering new specificities, understanding the evolution and ecological impact of tailocins may enable the design of promising candidates for novel targeted antibiotics. [ABSTRACT FROM AUTHOR]

This study investigated the ideal performance of non-recirculating Anaerobic Fluidized Bed Reactors (AnFBRs) for treating organic wastewater of varying strengths under low Hydraulic Retention Time (HRT). Four 4.58 L AnFBRs were used to treat synthetic wastewater with an Organic Loading Rate (OLR) ranging from 4.50 to 40.11 gCOD/L-d, and HRT between 1.1 and 4.4 hours. The AnFBRs achieved high removal efficiencies ranging from 83 % to 96 % at steady state, except during the organic shock load, which reduced removal performance to 12 %. Shortened HRT conditions led to a decreasing trend in reactor pH due to an incomplete anaerobic cycle. The modified Stover-Kincannon model estimated the maximum substrate utilization rate of AnFBR's to be 196.08 gCOD/L-d, with a correlation coefficient of 0.98. Under shortended HRT, microbial diversity analysis identified predominant non-filamentous bacterial families, such as Streptococcaceae and Veillonellaceae, which collaborate during biofilm development in anaerobic environments. It was suggested that the porous media provided secure attachment sites for the biomass growth and biofilm formation under shock load and high shear force conditions. While these results offer valuable insights, further studies are needed to confirm these findings and enhance the understanding of the use porous media in non-recirculating AnFBRs. [Display omitted] • Low-density media allow fluidization in a non-recirculating configuration. • The reactor contributes to good performance under severe conditions. • The downward trend in environmental parameters stands for practical limitation. • Microbial diversity result signifies a new assumption in use of porous media. • Maximum utilization rate 196.08 in unit of organic load present ideal conditions [ABSTRACT FROM AUTHOR]

Ceftriaxone is an antibiotic that increases central nervous system (CNS) protein expression of the glutamate transporters GLT-1 and xCT and ameliorates pathological behaviors in rodent models of neurological disease and substance use disorder. However, little ceftriaxone passes through the blood–brain barrier, the CNS binding partner of ceftriaxone is unknown, and ceftriaxone does not consistently upregulate GLT-1 and xCT in cell culture. Ceftriaxone alters the gut microbiome composition in rodents and humans, and the microbiome–gut–brain axis regulates drug-seeking. Thus, here we test the hypothesis that ceftriaxone reduces alcohol intake while ameliorating alcohol-induced disruption of the gut microbiome composition. Male and female Sprague–Dawley rats received intermittent access to alcohol (IAA) while controls received access to only water. Following 17 IAA sessions, ceftriaxone/vehicle treatment was given for 5 days. Analysis of the gut microbiome composition was assessed by 16S rRNA gene amplicon sequencing conducted on fecal pellets collected prior to and after alcohol consumption and following ceftriaxone treatment. Male rats displayed escalated alcohol intake and preference over the course of the 17 sessions; however, total alcohol intake did not differ between the sexes. Ceftriaxone reduced alcohol intake and preference in male and female rats. While alcohol affected a diverse set of amplicon sequencing variants (ASV), ceftriaxone markedly reduced the diversity of microbial communities reflected by a blooming of the Enterococcaceae family. The remaining effects of ceftriaxone, however, encompassed families both affected and unaffected by prior alcohol drinking and highlight the Ruminococcaceae and Muribaculaceae families as bidirectionally modulated by alcohol and ceftriaxone. Altogether, our study confirms that ceftriaxone reduces alcohol intake in rats and partially reverses alcohol-induced dysbiosis. • Total amount of alcohol intake did not differ by sex. • Ceftriaxone reduced alcohol intake and preference in male and female rats. • Ceftriaxone markedly reduced the diversity of microbial communities. • Ceftriaxone partially reverses alcohol-induced dysbiosis. [ABSTRACT FROM AUTHOR]

The influential rare biosphere concept in microbial ecology focuses on taxonomic scarcity and treats functional rarity implicitly. Microbes can possess functions distinct from other taxa in a community and can be present at high or low abundances. We define functionally rare microbes as possessing distinct functions and being numerically scarce. Functionally rare microbes can contribute disproportionately to ecosystem multifunctionality. The functional rarity concept helps to mechanistically connect microbial functional diversity, ecosystem functioning, and evolutionary processes. It also highlights the need for conservation of rare functions in microbial communities. The influential concept of the rare biosphere in microbial ecology has underscored the importance of taxa occurring at low abundances yet potentially playing key roles in communities and ecosystems. Here, we refocus the concept of rare biosphere through a functional trait-based lens and provide a framework to characterize microbial functional rarity, a combination of numerical scarcity across space or time and trait distinctiveness. We demonstrate how this novel interpretation of the rare biosphere, rooted in microbial functions, can enhance our mechanistic understanding of microbial community structure. It also sheds light on functionally distinct microbes, directing conservation efforts towards taxa harboring rare yet ecologically crucial functions. [ABSTRACT FROM AUTHOR]

Trade-offs between soil functions hamper maximizing soil multifunctionality in agroecosystems. Taking soil microbial functional trade-offs into consideration in agricultural management is crucial for optimizing the impacts of changes in soil microbial communities on soil health in agroecosystems. Interactions within soil microbial communities influence functional trade-offs. Manipulating soil microbial diversity and interactions through soil health-improving management can alleviate functional trade-offs and improve soil health and agricultural sustainability. Better mechanistic understanding of the interdependencies between soil-induced functions is essential to improve soil health and agricultural sustainability. Soil microbial communities play pivotal roles in maintaining soil health in agroecosystems. However, how the delivery of multiple microbial functions in agroecosystems is maintained remains poorly understood. This may put us at risk of incurring unexpected trade-offs between soil functions. We elucidate how interactions between soil microbes can lead to trade-offs in the functioning of agricultural soils. Interactions within soil microbial communities can result in not only positive but also neutral and negative relationships among soil functions. Altering soil conditions through soil health-improving agricultural management can alleviate these functional trade-offs by promoting the diversity and interrelationships of soil microbes, which can help to achieve more productive and sustainable agroecosystems. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. Traditional fermented milks are produced through an inoculation process that involves the deliberate introduction of microorganisms that have been adapted and perpetuated across successive generations. However, the changes in the microbiota of traditional fermented milk during long-term inoculation fermentation in a laboratory environment remain unclear. In this study, we collected 5 samples of traditional fermented milk samples from 5 different counties in Tibet (3 kurut products) and Xinjiang (2 tarag products) of China, which served as starter cultures for a 9-mo continuous inoculation fermentation experiment. We analyzed the inter- and intrapopulation variations in the microbial communities of the collected samples, representing their macrodiversity and microdiversity, using shotgun metagenomic sequencing. Across all samples, we obtained a total of 186 high-quality metagenomic-assembled genomes, including 7 genera and 13 species with a relative abundance of more than 1%. The majority of these genomes were annotated as Lactobacillus helveticus (60.46%), Enterococcus durans (9.52%), and Limosilactobacillus fermentum (6.23%). We observed significant differences in species composition and abundance among the 5 initial inoculants. During the long-term inoculation fermentation, we found an overall increasing trend in species diversity, composition, and abundances of carbohydrate metabolism module-encoding genes in the fermented milk bacterial metagenome, while the fermented milk virome exhibited a relatively narrow range of variation. Lactobacillus helveticus, a dominant species in traditional fermented milk, displayed high stability during the long-term inoculation fermentation. Our study provides valuable insights for the industrial production of traditional fermented milk. [ABSTRACT FROM AUTHOR]

Humic acid (HA) is a typical refractory organic matter, so it is of great significance to investigate its effect on the performance of Anammox granular sludge. When the dosage of HA ≤ 50 mg/L, HA promotes the total nitrogen removal rate (NRR) to 1.45 kg/(m3·day). When HA was between 50 and 100 mg/L, the NRR of Anammox was stable. At this time, the adsorption of HA causes the sludge to gradually turn from red to brown, but the activities of heme and enzymes showed that its capacity was not affected. When HA levels reached 250 mg/L, the NRR dropped to 0.11 kg/(m3·day). Moderate HA levels promoted the release of extracellular polymeric substance (EPS), but excessive HA levels lead to a decrease in EPS concentrations. HA inhibited Anammox activity, which indirectly hindered the transmission of substrate and accumulated substrate toxicity. Although HA promoted the increase of heterotrophic microbial abundance in Anammox system, the microbial diversity decreased gradually. With the increase of HA concentration, the abundance of Candidatus_Brocadia , the main functional microorganism of Anammox system, decreased gradually, while the abundance of Candidatus_Kuenenia increased gradually. [ABSTRACT FROM AUTHOR]

• A metaproteomics-based comparison of microbial degradation from ASP to AB was conducted. • Upgrading from ASP to AB increased lignocellulose degradation rates by 18.49-46.52%. • The upgrade from ASP to AB improved diversity of CAZyme-producing microbes. • AB but not ASP can produce the key enzyme for acetate conversion. • AB was superior to ASP for compost decomposition with higher cellulose. Composting presents a viable management solution for lignocellulose-rich municipal solid waste. However, our understanding about the microbial metabolic mechanisms involved in the biodegradation of lignocellulose, particularly in industrial-scale composting plants, remains limited. This study employed metaproteomics to compare the impact of upgrading from aerated static pile (ASP) to agitated bed (AB) systems on physicochemical parameters, lignocellulose biodegradation, and microbial metabolic pathways during large-scale biowaste composting process, marking the first investigation of its kind. The degradation rates of lignocellulose including cellulose, hemicellulose, and lignin were significantly higher in AB (8.21%-32.54%, 10.21%-39.41%, and 6.21%-26.78%) than those (5.72%-23.15%, 7.01%-33.26%, and 4.79%-19.76%) in ASP at three thermal stages, respectively. The AB system in comparison to ASP increased the carbohydrate-active enzymes (CAZymes) abundance and production of the three essential enzymes required for lignocellulose decomposition involving a mixture of bacteria and fungi (i.e., Actinobacteria, Bacilli, Sordariomycetes and Eurotiomycetes). Conversely, ASP primarily produced exoglucanase and β-glucosidase via fungi (i.e., Ascomycota). Moreover, AB effectively mitigated microbial stress caused by acetic acid accumulation by regulating the key enzymes involved in acetate conversion, including acetyl-coenzyme A synthetase and acetate kinase. Overall, the AB upgraded from ASP facilitated the lignocellulose degradation and fostered more diverse functional microbial communities in large-scale composting. Our findings offer a valuable scientific basis to guide the engineering feasibility and environmental sustainability for large-scale industrial composting plants for treating lignocellulose-rich waste. These findings have important implications for establishing green sustainable development models (e.g., a circular economy based on material recovery) and for achieving sustainable development goals. [Display omitted] [ABSTRACT FROM AUTHOR]

• Novel carbon source and corncob had better denitrification efficiency than polycaprolactone and polyvinyl alcohol-sodium alginate. • The taxonomical composition of bacterial, fungal and archaeal communities can be altered by types of solid carbon source. • Some fungi and archaea species were conducive to solid-phase denitrification (SPD) systems. • Co-occurring network showed some potential collaboration between bacterial fungal and archaeal communities in SPD systems. • Amplicon sequence variant (ASV) can identify more taxonomies that operational taxonomic unit (OTU) cannot in this study. There is a lack of understanding about the bacterial, fungal and archaeal communities' composition of solid-phase denitrification (SPD) systems. We investigated four SPD systems with different carbon sources by analyzing microbial gene sequences based on operational taxonomic unit (OTU) and amplicon sequence variant (ASV). The results showed that the corncob-polyvinyl alcohol sodium alginate-polycaprolactone (CPSP, 0.86±0.04 mg NO 3 −-N/(g·day)) and corncob (0.85±0.06 mg NO 3 −-N/(g·day)) had better denitrification efficiency than polycaprolactone (PCL, 0.29±0.11 mg NO 3 −-N/(g·day)) and polyvinyl alcohol-sodium alginate (PVA-SA, 0.24±0.07 mg NO 3 −-N/(g·day)). The bacterial, fungal and archaeal microbial composition was significantly different among carbon source types such as Proteobacteria in PCL (OTU: 83.72%, ASV: 82.49%) and Rozellomycota in PVA-SA (OTU: 71.99%, ASV: 81.30%). ASV methods can read more microbial units than that of OTU and exhibit higher alpha diversity and classify some species that had not been identified by OTU such as Nanoarchaeota phylum, unclassified_ f_ Xanthobacteraceae genus, etc., indicating ASV may be more conducive to understand SPD microbial communities. The co-occurring network showed some correlation between the bacteria fungi and archaea species, indicating different species may collaborate in SPD systems. Similar KEGG function prediction results were obtained in two bioinformatic methods generally and some fungi and archaea functions should not be ignored in SPD systems. These results may be beneficial for understanding microbial communities in SPD systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Posttraumatic stress disorder (PTSD) is a common consequence of traumatic injury, yet certain biological factors contributing to PTSD are poorly understood. The gut microbiome may influence mental health outcomes, but its role in heterogeneous PTSD presentations requires elucidation. Bacterial composition was examined in adults 2–4 years post-trauma with probable PTSD (n = 24) versus trauma-exposed controls without probable PTSD (n = 24). 16S rRNA sequencing and bioinformatic tools assessed microbial diversity and abundance. Relationships between taxa and PTSD symptom clusters were evaluated. No differences were found in overall microbial community structure between groups. The probable PTSD group exhibited significantly reduced Actinobacteriota and increased Verrucomicrobiota phylum abundance compared to controls. Specific taxa showed notable inverse associations with negative mood/cognition versus hyperarousal symptoms. Prevotella and Ruminococcaceae were negatively associated with negative mood but positively associated with hyperarousal. Results demonstrate microbial signatures of probable PTSD subtypes, highlighting the microbiome as a potential mediator of heterogeneous trauma psychopathology. Definition of PTSD microbial correlates provides a foundation for personalized psychobiotic interventions targeting predominant symptom profiles. • PTSD group had lower relative Actinobacteriota, higher Verrucomicrobiota compared to controls. • No differences in overall community structure, diversity, or other major phyla • Prevotella, Ruminococcaceae, Lachnospiraceae inversely related to symptom clusters. • Findings suggest microbial heterogeneity across PTSD subtypes. [ABSTRACT FROM AUTHOR]

Nocardioform placentitis is a poorly understood disease of equine late gestation. The presence of nocardioform, filamentous branching gram-positive bacteria, has been linked to the disease, with Crossiella equi , Amycolatopsis spp., and Streptomyces spp. being the most frequently identified bacteria. However, these bacteria are not found in all clinical cases in addition to being isolated from healthy, normal postpartum placentas. To better understand this form of placentitis, we analyzed the microbial composition in the equine placenta (chorioallantois) of both healthy postpartum (control; n = 11) and nocardioform-affected samples (n = 22) using 16S rDNA sequencing. We found a lower Shannon index in nocardioform samples, a higher Chao1 index in nocardioform samples, and a difference in beta diversity between control and nocardioform samples (p < 0.05), suggesting the presence of dysbiosis during the disease. In the majority of the NP samples (77 %), one of the following genera— Amycolatopsis , Crossiella , Lentzea , an unidentified member of the Pseudonocardiaceae family, Mycobacterium, or Enterococcus —represented over 70 % of the relative abundance. Overall, the data suggest that a broader spectrum of potential opportunistic pathogens could be involved in nocardioform placentitis, extending beyond the traditionally recognized bacteria, resulting in a similar histomorphological profile. • Non-nocardioform opportunistic pathogens may be associated with placentitis. • Nocardioform placentitis is associated with dysbiotic changes. • Nocardioform placentitis exhibits a unique microbial diversity distinct from control samples. [ABSTRACT FROM AUTHOR]

Little is known about the effect of gut microbial and extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) carriage, particularly in the general population. The aim of this study was to identify microbiota signatures uniquely correlated with ESBL-E carriage. We conducted a case–control study among individuals seeking care at the Sexual Health Clinic or Department of Infectious and Tropical Diseases, Saint-Antoine Hospital, Paris, France. Using coarsened exact matching, 176 participants with ESBL-carriage (i.e. cases) were matched 1:1 to those without ESBL-carriage (i.e. controls) based on sexual group, ESBL-E prevalence of countries travelled in <12 months, number of sexual partners in <6 months, geographic origin, and any antibiotic use in <6 months. 16S rRNA gene amplicon sequencing was used to generate differential abundances at the genus level and measures of α- and β-diversity. Participants were mostly men (83.2%, n = 293/352) and had a median age of 33 years (interquartile range: 27–44). Nine genera were found associated with ESBL-E carriage: Proteus (p < 0.0001), Carnobacterium (p < 0.0001), Enterorhabdus (p 0.0079), Catonella (p 0.017), Dermacoccus (p 0.017), Escherichia/Shigella (p 0.021), Kocuria (p 0.023), Bacillus (p 0.040), and Filifactor (p 0.043); however, differences were no longer significant after Benjamini–Hochberg correction (q > 0.05). There were no differences between those with versus without ESBL-E carriage in measures of α -diversity (Shannon Diversity Index, p 0.49; Simpson Diversity Index, p 0.54; and Chao1 Richness Estimator, p 0.16) or β -diversity (Bray–Curtis dissimilarity index, p 0.42). In this large carefully controlled study, there is lacking evidence that gut microbial composition and diversity is any different between individuals with and without ESBL-E carriage. [ABSTRACT FROM AUTHOR]

The Arctic, an essential ecosystem on Earth, is subject to pronounced anthropogenic pressures, most notable being the climate change and risks of crude oil pollution. As crucial elements of Arctic environments, benthic microbiomes are involved in climate-relevant biogeochemical cycles and hold the potential to remediate upcoming contamination. Yet, the Arctic benthic microbiomes are among the least explored biomes on the planet. Here we combined geochemical analyses, incubation experiments, and microbial community profiling to detail the biogeography and biodegradation potential of Arctic sedimentary microbiomes in the northern Barents Sea. The results revealed a predominance of bacterial and archaea phyla typically found in the deep marine biosphere, such as Chloroflexi, Atribacteria , and Bathyarcheaota. The topmost benthic communities were spatially structured by sedimentary organic carbon, lacking a clear distinction among geographic regions. With increasing sediment depth, the community structure exhibited stratigraphic variability that could be correlated to redox geochemistry of sediments. The benthic microbiomes harbored multiple taxa capable of oxidizing hydrocarbons using aerobic and anaerobic pathways. Incubation of surface sediments with crude oil led to proliferation of several genera from the so-called rare biosphere. These include Alkalimarinus and Halioglobus , previously unrecognized as hydrocarbon-degrading genera, both harboring the full genetic potential for aerobic alkane oxidation. These findings increase our understanding of the taxonomic inventory and functional potential of unstudied benthic microbiomes in the Arctic. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. In commercial dairy production systems, feeding calves once daily could be an alternative to reduce labor expenses. Several studies comparing once-a-day (OAD) versus twice-a-day (TAD) milk feeding systems have not evidenced differences in calf growth, rumen development, blood parameters or health scores, but effect on ruminal microbiota remains to be investigated. The objective of this study was to determine the effects of OAD or TAD on the establishment of the ruminal microbiota and its metabolic activity. Sixteen male calves (45.9 ± 5.7 kg at birth) were involved in the trial from birth to weaning (63 d). After the colostrum phase, 2 feeding programs based on a milk replacer were tested and calves were allocated to these programs on d 5. To study the establishment of the bacterial community, ruminal fluid was obtained from each calf 1 h after the morning meal at 7, 35, and 63 d of age. The ruminal metabolome was evaluated at a 7-d interval from d 1 to d 63. Ruminal microbiota and metabolite profiles were characterized by 16 S rRNA gene sequencing- and by 1H nuclear magnetic resonance spectroscopy, respectively. Our results showed that feeding milk replacer once or TAD did not change the ruminal microbiota and metabolites of dairy calves from birth to weaning. Microbial data showed that diversity and richness increased with age, suggesting a shift from a heterogeneous and less diverse community after birth (d 7) to a more diverse but homogeneous community at 35 and 63 d. These findings suggest that feeding milk OAD can be successfully applied to a calf feeding system without compromising microbial establishment and functions. [ABSTRACT FROM AUTHOR]

The intestinal microbiota plays a pivotal role in digestive processes and maintains gut health and intestinal homeostasis. These functions may be compromised by increased environmental heat, which in turn reduces feed intake and gut integrity and activates the intestinal immune system. It remains unknown whether high ambient temperatures, which cause heat stress (HS) in dairy cows, disturb the eubiosis of the microbial community, and if so, to which extent the reduction in feed intake and the impairment of circulating and intestinal metabolites account for the alterations of the jejunal microbiota. To address these questions, jejunal digesta, mucosa, and plasma samples were collected from cows exposed to heat stress (HS; 28°C, temperature-humidity index [THI] = 76, n = 10), control conditions (CON; 16°C, THI = 60, n = 10), or pair-fed (PF; 16°C, THI = 60, n = 10) for 7 d. Digesta fluids were examined for pH, acetate, nonesterified fatty acids (NEFA), glucose, and lactate, and plasma samples were analyzed for glucose, lactate, BHB, triglycerides, NEFA, creatinine, and urea. The microbiota of the digesta and mucosa samples were analyzed by 16S rRNA sequencing. The α-diversity was higher in mucosa than digesta but was not affected by high ambient temperatures. However, the mucosa-associated microbiota appeared more responsive to ambient heat than the digesta microbiome. The adaptive responses under HS conditions comprised an increased mucosal abundance of Bifidobacteriaceae , Succinivibrionaceae UCG-001, Clostridia and Lactobacillus. In the digesta, HS has exerted effects on microbial abundance of Colidextribacter , and Lachnospiraceae UCG-008. Several correlations between plasma or intestinal metabolites and microbiota were elucidated, including Methanobacteriaceae correlating positively with plasma BHB and digesta glucose concentrations. Moreover, the reduction in feed intake during HS had non-negligible effects on microbial diversity and the abundance of certain taxa, underpinning the importance of nutrient supply on maintaining intestinal homeostasis. [ABSTRACT FROM AUTHOR]

Microbes within the gastrointestinal tract have emerged as modulators of the host's health. Obstructive sleep apnea (OSA) is characterized by intermittent partial, or complete, airway closure during sleep and is associated with increased risk of non-communicable diseases as well as dysbiosis of the gut microbiome. Thus, we investigated if improving nocturnal airway patency via positive airway pressure (PAP) therapy improves gut microbial diversity in recently diagnosed patients with moderate-to-severe OSA (apnea-hypopnea index ≥15.0 events/hr). Eight subjects (3 F, 56±9yrs, 33.5 ± 7.7 kg/m2, 45.0 ± 38.4 events/hr) provided stool samples before, and two months after, PAP therapy (mean adherence of 95 ± 6%, residual apnea-hypopnea index of 4.7 ± 4.6 events/hr). While the Shannon diversity index tended to increase following PAP (3.96 ± 0.52 to 4.18 ± 0.56, p = 0.08), there were no changes in the Observed (1,088 ± 237 to 1,136 ± 289, p = 0.28) nor Inverse-Simpson (22.4 ± 12.99 to 26.6 ± 18.23, p = 0.28) alpha diversity indices. There were also no changes in beta diversity assessed using the Bray-Curtis (p = 0.98), Jaccard (p = 0.99), WUniFrac (p = 0.98), GUniFrac (p = 0.98), or UniFrac (p = 0.98) methods. No changes in differential abundance taxa were found using a false discovery rate threshold of <0.20. Our data are the first to report that PAP therapy may not offset, or reverse, gut dysbiosis in patients with OSA. Accordingly, interventions which improve gut microbial health should be explored as potential adjunctive treatment options in patients with OSA to reduce their risk of developing non-communicable diseases. • The gut microbiome is a key contributor to the host's health. • Dysbiosis of the microbiome is observed in patients with obstructive sleep apnea. • Positive airway pressure does not offset or reverse dysbiosis in sleep apnea. [ABSTRACT FROM AUTHOR]

In neonates, the gastrointestinal tract is rapidly colonized by bacteria after birth. Gut microbiota development is critical during the first few years of life. However, disruption of gut microbiota development in neonates can lead to gut dysbiosis, characterized by overcolonization by pathogenic bacteria and delayed or failed maturation toward increasing microbial diversity and Fermicutes dominance. Gut dysbiosis can predispose infants to sepsis. Pathogenic bacteria can colonize the gut prior to sepsis and cause sepsis through translocation. This review explores gut microbiota development in neonates, the evidence linking gut dysbiosis to neonatal sepsis, and the potential role of probiotics in gut microbiota modulation and sepsis prevention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent advances in microbial diversity and key taxa in saline soils are summarized. • The threshold effect of salinity on soil C and N turnover exists in salinized soils. • Soil microorganisms have higher resistance to salt stress in already salinized soils. • Salt-tolerant microorganisms promote plant growth in a variety of ways. • Microbial resources developed by multi-omics are beneficial to saline ecosystems. Soil salinization threatens food security and ecosystem health, and is one of the important drivers to the degradation of many ecosystems around the world. Soil microorganisms have extremely high diversity and participate in a variety of key ecological processes. They are important guarantees for soil health and sustainable ecosystem development. However, our understanding of the diversity and function of soil microorganisms under the change of increased soil salinization is fragmented. Here, we summarize the changes in soil microbial diversity and function under the influence of soil salinization in diverse natural ecosystems. We particularly focus on the diversity of soil bacteria and fungi under salt stress and the changes in their emerging functions (such as their mediated biogeochemical processes). This study also discusses how to use the soil microbiome in saline soils to deal with soil salinization for supporting sustainable ecosystems, and puts forward the knowledge gaps and the research directions that need to be strengthened in the future. Due to the rapid development of molecular-based biotechnology (especially high-throughput sequencing technology), the diversity and community composition and functional genes of soil microorganisms have been extensively characterized in different habitats. Clarifying the responding pattern of microbial-mediated nutrient cycling under salt stress and developing and utilizing microorganisms to weaken the adverse effects of salt stress on plants and soil, which are of guiding significance for agricultural production and ecosystem management in saline lands. [ABSTRACT FROM AUTHOR]

Long-term deposition of atmospheric pollutants emitted from coal combustion and their effects on the eco-environment have been extensively studied around coal-fired power plants. However, the effects of coal-fired power plants on soil microbial communities have received little attention through atmospheric pollutant deposition and coal-stacking. Here, we collected the samples of power plant soils (PS), coal-stacking soils (CSS) and agricultural soils (AS) around three coal-fired power plants and background control soils (BG) in Huainan, a typical mineral resource-based city in East China, and investigated the microbial diversity and community structures through a high-throughput sequencing technique. Coal-stacking significantly increased (p < 0.05) the contents of total carbon, total nitrogen, total sulfur and Mo in the soils, whereas the deposition of atmospheric pollutants enhanced the levels of V, Cu, Zn and Pb. Proteobacteria, Actinobacteria, Thaumarchaeota, Thermoplasmata, Ascomycota and Basidiomycota were the dominant taxa in all soils. The bacterial community showed significant differences (p < 0.05) among PS, CSS, AS and BG, whereas archaeal and fungal communities showed significant differences (p < 0.01) according to soil samples around three coal-fired power plants. The predominant environmental variables affecting soil bacterial, archaeal and fungal communities were Mo-TN-TS, Cu-V-Mo, and organic matter (OM)-Mo, respectively. Certain soil microbial genera were closely related to multiple key factors associated with stacking coal and heavy metal deposition from power plants. This study provided useful insight into better understanding of the relationships between soil microbial communities and long-term disturbances from coal-fired power plants. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, perovskite-structured LaNi 0.5 Fe 0.5 O 3 nanoparticles (NPs) are successfully synthesized to explore influence of addition amounts on biohydrogen yield. The great potential advantages to improve the biohydrogen production under mesophilic and thermophilic dark fermentation are systematically investigated by a series of experiments. The characterization of physicochemical properties of LaNi 0.5 Fe 0.5 O 3 NPs are summarized and analyzed. The highest biohydrogen yield 262.55 mL/g of mesophilic dark fermentation is obtained at 100 mg/L LaNi 0.5 Fe 0.5 O 3 NPs group while under thermophilic condition, the maximum of biohydrogen production is only 182.13 mL/g with 200 mg/L LaNi 0.5 Fe 0.5 O 3 supplementation, which are higher 50.7% and 91.0% than that of corresponding control groups, respectively. The analysis of soluble microbial products (SMPs) suggests that LaNi 0.5 Fe 0.5 O 3 NPs can observably enhance the butyrate-type metabolic pathway, being consistent with the raising abundance of Clostridium butyricum in mesophilic fermentation. The extracellular polymer content is significantly increased with appropriate addition of LaNi 0.5 Fe 0.5 O 3 NPs. The results reveal that the moderate amount of LaNi 0.5 Fe 0.5 O 3 NPs can even optimize the microbial community structure by increasing the abundance of Clostridium sensu stricto 1 under mesophilic fermentation and Clostridium sensu stricto 7 as well as Longonea under thermophilic fermentation. Eventually, it can be affirmatively concluded that the application of LaNi 0.5 Fe 0.5 O 3 NPs to dark fermentation contributes to more biohydrogen yield with moderate amounts under both mesophilic and thermophilic conditions. The innovative work of nickel doped lanthanum-iron oxide nanoparticles provides an effective strategy to take the fully advantage of Fe and Ni element for biohydrogen yield. [Display omitted] • Perovskite-structured LaNi 0.5 Fe 0.5 O 3 NPs are successfully fabricated to enhance biohydrogen yield. • Biohydrogen yield is significantly increased in both fermentation system modified by LaNi 0.5 Fe 0.5 O 3 NPs. • Butyrate-type metabolic pathway is selectively strengthened for more biohydrogen production by LaNi 0.5 Fe 0.5 O 3 NPs. • Microbial diversity and hydrogenase activity are greatly improved by the addition of LaNi 0.5 Fe 0.5 O 3 NPs. • LaNi 0.5 Fe 0.5 O 3 NPs can optimize microbial community composition toward hydrogen-producing species. [ABSTRACT FROM AUTHOR]

The wide application of CdSe quantum dots (QDs) increases its stress risk to sewage treatment systems. This study evaluated the response of nitrification performance, floc characteristics and microbial community of nitrifying sludge under long-term exposure to CdSe QDs. Results showed CdSe QDs (≥ 1 mg/L) would decrease the activity of ammonia monooxygenase (AMO). Under the stress of 30 mg/L CdSe QDs, the activity of AMO was reduced by 66%, while the activities of hydroxylamine oxidase and nitrite oxidoreductase were enhanced by 19.1% and 26%, respectively. Thus, the final nitrification effects were not adversely affected, and the production rates of NO 2 −-N and NO 3 −-N were accelerated. Additionally, CdSe QDs improved biomass concentration in sludge and maintained the stability of sludge settleability. High throughput sequencing analysis showed that CdSe QDs evidently reduced the abundance and diversity of microbial community in nitrifying sludge. The abundances of amino acid metabolism and lipid metabolism were enriched. Moreover, CdSe QDs decreased the fluorescence intensity of tryptophan-like protein from 2,326 to 1,179 a.u. in loosely bound extracellular polymeric substances (EPSs) and from 3,792 to 3,117 a.u. in tightly bound EPSs. To relieve CdSe QD stress, the polysaccharide content increased from 0.31 to 0.61 mg/g MLSS and intracellular antioxidant defense was activated. With CdSe QD level increasing to 30 mg/L, the total antioxygenic capacity and the activities of catalase were enhanced up to 411% and 143.2%, respectively. Thereby, CdSe QDs had little adverse effects on cell membrane integrity, microbial metabolism and the abundance of Nitrospirae. [ABSTRACT FROM AUTHOR]

Microbes are key biodiversity components of all ecosystems and control vital ecosystem functions. Although we have just begun to unravel the scales and factors that regulate microbial communities, their role in mediating ecosystem stability in response to disturbances remains underexplored. Here, we review evidence of how, when, and where microbes regulate or drive disturbance feedbacks. Negative feedbacks dampen the impacts of disturbance, which maintain ecosystem stability, whereas positive feedbacks instead erode stability by amplifying the disturbance. Here we describe the processes underlying the responses to disturbance using a hierarchy of functional traits, and we exemplify how these may drive biogeochemical feedbacks. We suggest that the feedback potential of functional traits at different hierarchical levels is contingent on the complexity and heterogeneity of the environment. Microbial functioning is intrinsically linked to the resistance and resilience of ecosystems. Microbes drive and regulate disturbance feedbacks that impact ecosystem stability. Functional traits from delineated genotypes to community-wide traits mediate the intensity and direction of feedbacks. Feedbacks can be positive (amplifying) or negative (dampening) and emerge from altered biogeochemical cycling related to microbial disturbance responses. Generalizable frameworks for how microbes adapt to disturbances in time and space are needed to increase the understanding and predictability of feedbacks and the temporal stability of ecosystems. [ABSTRACT FROM AUTHOR]

Milk fan is an acid-curd cheese with strong national characteristics (a traditional dairy product of the Bai nationality with a shape like a piece of paper) and a long history in Yunnan province, China. In our previous study, we characterized the microbial community diversity of milk fan, but the succession of microorganisms associated with flavor formation in milk fan is still unknown. Therefore, we examined the predominant microorganisms and their correlations with the formation of flavor in the fermentation of sour juice and drying of milk fan by gas chromatography mass spectrometry, high-throughput 16S rDNA sequencing, intergenic spacer sequencing and metatranscriptome analysis. We found that the relative abundances of Lactobacillus and Issatchenkia initially decreased and then increased with time during the fermentation of sour juice. However, the relative abundances of Acetobacter , Leuconostoc , Lactococcus, Geotrichum , and Dipodascus initially increased and then decreased. During the drying step, the relative abundances of Lactobacillus and Issatchenkia continuously increased and became the dominant microorganisms in the milk fan. The metatranscriptomes generated from the milk fan showed that "carbohydrate metabolism," "translation," and "signal transduction" were the main metabolic functions of the microbial communities. Rhodotorula and Yarrowia contained more differentially expressed genes than other genera, which indicated they may be associated with the production of the characteristic flavor. Furthermore, a Pearson correlation analysis showed that Lactococcus , Rhodotorula , Candida , Cutaneotrichosporon , and Yarrowia were significantly positively correlated with more aroma-active compounds, mainly ethyl acetate, 2-heptanone, isovaleraldehyde, butyric acid, nonanal, and hexanal. In conclusion, these findings contribute to a better understanding of the flavor production mechanism during the production of milk fan. [Display omitted] [ABSTRACT FROM AUTHOR]

Aerobic composting can recycle nutrients from animal manure. Adding microorganism inoculants is an effective way to accelerate composting process. The study aimed to evaluate effects of inoculating with microbial agents on nitrogen conversion and bacterial community succession in pig manure composting. 3 composting treatments were conducted including no microbial inoculant (CK), inoculating thermophilic degrading bacteria (T1), and compound commercial microbial agents (T2). The results showed that T1 advanced the time for entering the thermophilic stage (>50 ℃), and accelerated organic matter degradation. T1 produced more NH 3 than other treatments. TN in group T1 and T2 was significantly greater than CK in composting maturity stage (after 14–15 d, T ≤ 40 ℃). (Final C/N)/(Initial C/N) of group T1 and T2 was 0.66, 0.65, and GI was 90.7 and 87.6, respectively. T1 improved the relative abundance of Actinobacteria, Firmicutes, Proteobacteria at the phylum level and increased Bacillus genera at genus level during the composting process. In conclusion, we demonstrated that pig manure composting added to thermophilic degrading bacteria effectively improved the quality of compost. [Display omitted] • Thermophilic microbial agents shortened the composting process and improved the quality of composting. • Inoculation with microbial agents improved the levels of the nitrate nitrogen and total nitrogen accumulation. • Key microbial groups increased the diversity of the microbial community and changed microbial community structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hyperuricemia has become a public health problem that needs to be solved urgently. • Sulforaphane may have great potential in reducing uric acid. • Sulforaphane provides benefits in epigenetic modification of Nrf2, intestinal homeostasis, and host metabolism. • Succinic acid and oxoglutaric acid were the critical host-gut microbiome co-metabolites of hyperuricaemic rats treated with sulforaphane. • The findings may provide a good means for efficiently preventing and treating hyperuricemia. Currently, revealing how to prevent and control hyperuricemia has become an essential public health issue. Sulforaphane has a wide range of applications in the management of hyperuricemia. The study objective was to verify the uric acid-lowering effects and the regulation of the gut-kidney axis mediated by sulforaphane and identify host-microbial co-metabolites in hyperuricemia. A hyperuricemia model was established by administering feedstuffs with 4% potassium oxonate and 20% yeast. Forty male Sprague–Dawley rats were randomly divided into the normal control, hyperuricemia, allopurinol, and sulforaphane groups. Animals were treated by oral gavage for six consecutive weeks, and then phenotypic parameters, metabolomic profiling, and metagenomic sequencing were performed. Sulforaphane could lower uric acid by decreasing urate synthesis and increasing renal urate excretion in hyperuricemic rats (P ＜0.05). We identified succinic acid and oxoglutaric acid as critical host-gut microbiome co-metabolites. Moreover, sulforaphane improved the diversity of microbial ecosystems and functions, as well as metabolic control of the kidney. Notably, sulforaphane exerted its renoprotective effect through epigenetic modification of Nrf2 and interaction between gut microbiota and epigenetic modification in hyperuricemic rats. We revealed that sulforaphane could ameliorate the progression of hyperuricemia by reprogramming the gut microbiome and metabolome. Our findings may provide a good means for efficiently preventing and treating hyperuricemia. [ABSTRACT FROM AUTHOR]

Microbiological and metabolomic analyses based on Illumina MiSeq high-throughput sequencing technology were carried out on the receiving rivers in upland habitats to compare the impacts of effluent discharges from two urban wastewater treatment processes on the receiving rivers. The results showed that microbial diversity increased in the lower reaches of the receiving rivers, but the overall microbial diversity of the rivers in the plateau habitat was lower than that in the plains. Proteobacteria (47.4%-57.04%) and Sphingorhabdus (25%-32.19%) were both the most abundant phylum and genus in the upper and lower reaches of the two feeder rivers. The effects of anaerobicanoxic-aerobic (AAO) vs. artificial wetland (CW) effluent discharge on microbial community abundance showed either an increase or a decrease, but analysis of Luteolibacter, an indicator bacterium of good water quality, found that abundance increased by 4.01% downstream of the AAO receiving river. Analysis of the downstream trend of dominant genera abundance suggests that the AAO receiving river has a stronger self-purification of pollutants and recovery of dominant genera. In terms of carbon, nitrogen, and phosphorus metabolic pathways and gene expression, AAO and CW treatment processes showed different significant effects on the receiving rivers and even had completely opposite effects on some functional modules. In addition, the AAO receiving river showed better recoverability in terms of carbon and phosphorus metabolic pathways. This study reveals the microbiological and carbon, nitrogen, and phosphorus metabolomic responses of the receiving rivers to sewage discharge in plateau habitats and provides a new practical idea and perspective for the selection of sewage treatment processes and sewage discharge in plateau towns. [ABSTRACT FROM AUTHOR]

In recent years, the biodegradable plastics has extensively used in industry, agriculture, and daily life. Herein, the effects of two biodegradable microplastics (BMPs), poly(butyleneadipate-co-terephthalate) (PBAT) and polyhydroxyalkanoate (PHA), on soil sulfamethoxazole (SMX) degradation and sul genes development were comparatively studied based on the type, dosage, and state. The addition of virgin BMPs significantly increased soil DOC following a sequential order PBAT > PHA and high dose > low dose. Meanwhile virgin PBAT significantly reduced soil pH. In general, the addition of BMPs not only promoted soil SMX degradation but also increased the abundance of sul genes, with an exception that pH reduction in virgin PBAT inhibited the proliferation of sul genes. The driving effects of BMPs on soil microbial diversity following the same order as that on DOC. Specific bacteria stimulated by BMPs, such as Arthrobacter and two genera affiliated with phylum TM7, accounted for the accelerated degradation of SMX. Intriguingly, UV-aging hindered the release of DOC from BMPs and the reduction in pH, mitigated the stimulation of microbial communities, and ultimately reduced the promotion effect of BMPs on SMX degradation and sul genes proliferation. Our results suggest that more attention should be paid to the proliferation risk of ARGs in the environment affected by BMPs and UV-aging can be employed sometimes to reduce this risk. [ABSTRACT FROM AUTHOR]

Blastocystis , once targeted as a harmful intestinal parasite, is now seen as potentially beneficial. Piperni et al. link its presence to improved gut health, higher microbial diversity, and favorable cardiometabolic outcomes, which suggests that Blastocystis might indicate a healthy diet and gut, possibly serving as a symbiont rather than a pathogen. [ABSTRACT FROM AUTHOR]

This study aimed to examine the association between anxiety symptoms and gut microbial composition and to infer their functional pathways. In total, 605 participants were included in this study. Participants were categorized into anxious and non-anxious groups according to their Beck Anxiety Inventory scores, and their fecal microbiota was profiled using 16S ribosomal RNA gene sequencing. The microbial diversity and taxonomic profiles of the participants with anxiety symptoms were analyzed using generalized linear models. The function of the gut microbiota was inferred by comparing 16S rRNA data between the anxious and non-anxious groups. The gut microbiome of the anxious group showed lower alpha diversity than that of the non-anxious group, and there were prominent differences in the community structure of the gut microbiota between the two groups. Male participants with anxiety had lower relative abundances of the family Oscillospiraceae, fibrolytic bacteria including those of the family Monoglobaceae, and short-chain fatty acid-producing bacteria such as those of the genus Lachnospiraceae_NK4A136 than those without anxiety symptoms. Female participants with anxiety symptoms had a lower relative abundance of the genus Prevotella than those without anxiety symptoms. The direction of causality between anxiety symptoms and the gut microbiota was unclear owing to the cross-sectional design of the study. Our results elucidate the association between anxiety symptoms and gut microbiota and provide insights for developing interventions to treat anxiety symptoms. • The gut microbiota of individuals with high levels of anxiety showed low alpha diversity. • Community structures of the gut microbiota differed between those with and without anxiety groups. • We identified sex-specific gut microbiota associated with anxiety symptoms. • Functional inference revealed enrichment of several metabolic pathways in the anxiety group. [ABSTRACT FROM AUTHOR]

• In-situ bioremediation efficiently removed TOC, TN, TP, iron and manganese. • Biolog assay showed that WLAS operation enhanced bacterial metabolic capacities. • WLAS operation altered the diversity and distribution of microbial communities. • Network analysis indicated that WLAS operation made microbes interact more closely. • ORP and TN were two key factors influencing the microbial community structures. Reservoirs have been served as the major source of drinking water for dozens of years. The water quality safety of large and medium reservoirs increasingly becomes the focus of public concern. Field test has proved that water-lifting and aeration system (WLAS) is a piece of effective equipment for in situ control and improvement of water quality. However, its intrinsic bioremediation mechanism, especially for nitrogen removal, still lacks in-depth investigation. Hence, the dynamic changes in water quality parameters, carbon source metabolism, species compositions and co-occurrence patterns of microbial communities were systematically studied in Jinpen Reservoir within a whole WLAS running cycle. The WLAS operation could efficiently reduce organic carbon (19.77%), nitrogen (21.55%) and phosphorus (65.60%), respectively. Biolog analysis revealed that the microbial metabolic capacities were enhanced via WLAS operation, especially in bottom water. High-throughput sequencing demonstrated that WLAS operation altered the diversity and distributions of microbial communities in the source water. The most dominant genus accountable for aerobic denitrification was identified as Dechloromonas. Furthermore, network analysis revealed that microorganisms interacted more closely through WLAS operation. Oxidation-reduction potential (ORP) and total nitrogen (TN) were regarded as the two main physicochemical parameters influencing microbial community structures, as confirmed by redundancy analysis (RDA) and Mantel test. Overall, the results will provide a scientific basis and an effective way for strengthening the in-situ bioremediation of micro-polluted source water. [Display omitted] [ABSTRACT FROM AUTHOR]

• Microbial diversity of oropharyngeal samples increased in infants with CF in the first year of life. • Age had strongest association with microbiota change in infants. • Antibiotic usage was associated with transient impacts on microbiota. Changes in upper airway microbiota may impact early disease manifestations in infants with cystic fibrosis (CF). To investigate early airway microbiota, the microbiota present in the oropharynx of CF infants over the first year of life was assessed along with the relationships between microbiota and growth, antibiotic use and other clinical variables. Oropharyngeal (OP) swabs were collected longitudinally between 1 and 12 months of age from infants diagnosed with CF by newborn screen and enrolled in the Baby Observational and Nutrition Study (BONUS). DNA extraction was performed after enzymatic digestion of OP swabs. Total bacterial load was determined by qPCR and community composition assessed using 16S rRNA gene analysis (V1/V2 region). Changes in diversity with age were evaluated using mixed models with cubic B-splines. Associations between clinical variables and bacterial taxa were determined using a canonical correlation analysis. 1,052 OP swabs collected from 205 infants with CF were analyzed. Most infants (77%) received at least one course of antibiotics during the study and 131 OP swabs were collected while the infant was prescribed an antibiotic. Alpha diversity increased with age and was only marginally impacted by antibiotic use. Community composition was most highly correlated with age and was only moderately correlated with antibiotic exposure, feeding method and weight z-scores. Relative abundance of Streptococcus decreased while Neisseria and other taxa increased over the first year. Age was more influential on the oropharyngeal microbiota of infants with CF than clinical variables including antibiotics in the first year of life. [ABSTRACT FROM AUTHOR]

• Endophytic bacterial community structure of medicinal plant D. nobile. • Microbial taxonomic diversity across D. nobile tissues. • Microbiota assemblages contribute to functional characteristics of D. nobile tissues. • Cross-talking relationships between bacterial genus in D. nobile. As a valuable medicinal epiphyte of Orchidaceae, Dendrobium nobile is widely utilized in Asian medicine. Despite the importance of Mycorrhizae in the germination of Dendrobium seeds, little is known about its endophytic microbiome. In the present study, 16S rRNA high-throughput sequencing is therefore applied to investigate the endophytic bacterial community structure associated with the different vegetative organs (roots, stems and leaves) of D. nobile. A total of 24 bacterial phyla and 448 genera of endophytes were identified, with Proteobacteria, Actinobacteria , and Acidobacteria being the dominant phyla. The relative abundance and diversity of endophytes in roots are found to be generally higher than those in stems and leaves. Most of the endophytes are predicted to be involved in nutrient metabolism, and some bacterial taxa are found to be involved in the recruitment of genera from the same phylum. Overall, the study provided important insights into the community structure and functional characteristics of endophytes in D. nobile , and lay a theoretical foundation for a better understanding of the interactive dialog between medicinal plants and their endophytes. [ABSTRACT FROM AUTHOR]

Bedding materials are important for suckling buffalo calves. Treated dung has been used as a bedding material for dairy cows but the lack of an appropriate safety assessment limits its application. In this study, we evaluated the feasibility of treated dung (TD) as a bedding material for suckling calves by comparing TD with rice husk (RH) and rice straw (RS) bedding materials. The TD was prepared through high-temperature composting by Bacillus subtilis. Thirty-three newborn suckling buffalo calves (Bubalus bubalis , 40.06 ± 5.79 kg) were randomly divided into 3 bedding material groups (TD, RH, and RS) and bedded with 1 of the 3 bedding materials for 60 d. We compared cost, moisture content, bacterial counts, and microbial composition of the 3 bedding materials, and investigated growth performance, health status, behavior, rumen fermentation, and blood parameters of bedded calves. The results showed that TD contained the fewest gram-negative bacteria and coliforms on d 1 and 30 and the lowest relative abundance of Staphylococcus throughout the experiment. The RH and TD bedding materials had the lowest cost. Calves in the TD and RS groups showed a higher dry matter intake, and final body weight and average daily gain in the TD and RS groups tended to be higher than in the RH group. Calves in the TD and RS groups had a lower disease incidence (diarrhea and fever), fewer antibiotic treatments, and lower fecal score than calves in the RH group. Higher contents of IgG, IgA, and IgM were observed in calves of the TD and RS groups than in calves of the RH group on d 10, indicating higher immune ability in TD and RS groups. Furthermore, TD bedding increased the butyric acid content in the calf's rumen, whereas RS bedding increased the acetate content, which might be attributed to the longer time and higher frequency of eating bedding material in the RS group. Considering all of the above indicators, we concluded that TD is the optimal bedding material for calves based on economics, bacterial count, microbial diversity, growth performance, and health status. Our findings provide a valuable reference for bedding material choice and calf farming. [ABSTRACT FROM AUTHOR]

Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting reproductive-aged women, but the cause remains unclear. Recent evidence has linked microbial composition with PCOS; however, the results are inconsistent. The aim of this systematic review was to gather current knowledge of the microbes across body sites (oral cavity, blood, vagina/cervix, gut) in women with PCOS, and meta-analyse the microbial diversity in PCOS. For this purpose, a systematic search using PubMed, Web of Science , Cochrane and Scopus was carried out. After selection, 34 studies met the inclusion criteria. Most of the studies associated changes in the microbiome with PCOS, whereas heterogeneity of the studies in terms of ethnicity, body mass index (BMI) and methodology, among other confounders, made it difficult to corroborate this relationship. In fact, 19 out of 34 of the studies were categorised as having high risk of bias when the quality assessment was conducted. Our meta-analysis on the gut microbiome of 14 studies demonstrated that women with PCOS possess significantly lower microbial alpha diversity compared with controls (SMD = –0.204; 95% CI –0.360 to –0.048; P = 0.010; I2 = 5.508, by Shannon Index), which may contribute to the development of PCOS. Nevertheless, future studies should specifically overcome the shortcomings of the current studies by through well planned and conducted studies with larger sample sizes, proper negative and positive controls and adequate case-control matching. [ABSTRACT FROM AUTHOR]

Mobile genetic elements such as plasmids and phages transfer genes between microbes, shaping the diversity and function of microbial communities. Hence, understanding the processes that govern the structure and dynamics of microbe–plasmid interactions is a fundamental goal of microbial ecology. Addressing this goal is challenging because communities are governed by processes that operate simultaneously at multiple levels of community organization. Complex adaptive systems theory, implemented via agent-based evolutionary modeling and extended by network analysis, is a promising framework to overcome these challenges. Using model comparison in combination with empirical data (experimental or from nature), researchers can quantify the relative importance of the key processes that shape the structure and function of microbial communities. Plasmids shape microbial communities' diversity, structure, and function. Nevertheless, we lack a mechanistic understanding of how community structure and dynamics emerge from local microbe–plasmid interactions and coevolution. Addressing this gap is challenging because multiple processes operate simultaneously at multiple levels of organization. For example, immunity operates between a plasmid and a cell, but incompatibility mechanisms regulate coexistence between plasmids. Conceptualizing microbe–plasmid communities as complex adaptive systems is a promising approach to overcoming these challenges. I illustrate how agent-based evolutionary modeling, extended by network analysis, can be used to quantify the relative importance of local processes governing community dynamics. These theoretical developments can advance our understanding of plasmid ecology and evolution, especially when combined with empirical data. [ABSTRACT FROM AUTHOR]

Microbial communities under Alpine regions show significant regional variation. As a main factor affecting microbial communities and metabolic processes, temperature was used as a single-factor control condition for 16S rRNA high-throughput sequencing analysis of microbial communities in anaerobic treatment systems in Alpine regions based on the Illumina MiSeq sequencing platform, and functional prediction was explored using the PICRUSt2 database. The results show that the biotic environment in Alpine regions can reduce microbial diversity. The microbial community composition is partially similar, and the microbial metabolic processes are slightly different. Low temperatures favor the methanogenesis module reaction, and for energy metabolism, 25°C is the optimal temperature working condition. [ABSTRACT FROM AUTHOR]

Previous research indicated that there is an aggregate of microorganism in oral cavity which takes part in promoting the occurrence of dental caries, but few studies on anticaries materials for these 'core microbiome' were developed. And We've found that DMAEM monomer has an obvious inhibitory effect on the growth of Streptococcus mutans and saliva biofilm, but the effect of that on the "core microbiome" of caries need further research. Thus, the objectives of this study were to explore the effect of DMAEM monomer on the core microbiota of dental caries, and to further study its anticaries effect. The changes of microbial structure and metabolic activity of the core microbiota biofilm were detected through measuring lactic acid yield, viable bacteria counts and demineralization depth, et al., and the anticaries potential in vivo of DMAEM monomer was evaluated by rat caries model. Meanwhile, high-throughput sequencing was used to analyze the microbial diversity change of saliva samples of rats. The results showed that DMAEM monomer could inhibit the growth of the core microbiota biofilm, decrease the metabolic activity and the acid production, as well as reduce the ability of demineralization under acidic conditions. Moreover, the degree of caries in the DMAEM group was significantly reduced, and the diversity and the evenness of oral microecology in the rats were statistically higher. In summary, DMAEM monomer could respond to acidic environment, significantly inhibit the cariogenic ability of the 'core microbiome' of caries, and help to maintain the microecological balance of oral cavity. [ABSTRACT FROM AUTHOR]

Scorodite (FeAsO 4 ·H 2 O) is a common arsenic-bearing (As-bearing) iron mineral in near-surface environments that could immobilize or store As in a bound state. In flooded soils, microbe induced Fe(III) or As(V) reduction can increase the mobility and bioavailability of As. Additionally, humic substances can act as electron shuttles to promote this process. The dynamics of As release and diversity of putative As(V)-reducing bacteria during scorodite reduction have yet to be investigated in detail in flooded soils. Here, the microbial reductive dissolution of scorodite was conducted in an flooded soil in the presence of anthraquinone-2,6-disulfonate (AQDS). Anaeromyxobacter, Dechloromonas, Geothrix, Geobacter, Ideonella , and Zoogloe a were found to be the dominant indigenous bacteria during Fe(III) and As(V) reduction. AQDS increased the relative abundance of dominant species, but did not change the diversity and microbial community of the systems with scorodite. Among these bacteria, Geobacter exhibited the greatest increase and was the dominant Fe(III)- and As(V)-reducing bacteria during the incubation with AQDS and scorodite. AQDS promoted both Fe(III) and As(V) reduction, and over 80% of released As(V) was microbially transformed to As(III). The increases in the abundance of arrA gene and putative arrA sequences of Geobacter were higher with AQDS than without AQDS. As a result, the addition of AQDS promoted microbial Fe(III) and As(V) release and reduction from As-bearing iron minerals into the environment. These results contribute to exploration of the transformation of As from As-bearing iron minerals under anaerobic conditions, thus providing insights into the bioremediation of As-contaminated soil. [ABSTRACT FROM AUTHOR]

• The primary pathway of BAC(C12) dissipation is microbial degradation. • Its half-life in soil is firstly reported and affected by organic matter content. • BAC(C12) decreased the α diversity of the soil microbial community. • BAC(C12) affects soil N transformation function by altering the abundance of functional microorganisms. As one typical cationic disinfectant, quaternary ammonium compounds (QACs) were approved for surface disinfection in the coronavirus disease 2019 pandemic and then unintentionally or intentionally released into the surrounding environment. Concerningly, it is still unclear how the soil microbial community succession happens and the nitrogen (N) cycling processes alter when exposed to QACs. In this study, one common QAC (benzalkonium chloride (BAC) was selected as the target contaminant, and its effects on the temporal changes in soil microbial community structure and nitrogen transformation processes were determined by qPCR and 16S rRNA sequencing-based methods. The results showed that the aerobic microbial degradation of BAC in the two different soils followed first-order kinetics with a half-life (4.92 vs. 17.33 days) highly dependent on the properties of the soil. BAC activated the abundance of N fixation gene (nifH) and nitrification genes (AOA and AOB) in the soil and inhibited that of denitrification gene (narG). BAC exposure resulted in the decrease of the alpha diversity of soil microbial community and the enrichment of Crenarchaeota and Proteobacteria. This study demonstrates that BAC degradation is accompanied by changes in soil microbial community structure and N transformation capacity. [Display omitted] [ABSTRACT FROM AUTHOR]

Movement is critical for the fitness of organisms, both large and small. It dictates how individuals acquire resources, evade predators, exchange genetic material, and respond to stressful environments. Movement also influences ecological and evolutionary dynamics at higher organizational levels, such as populations and communities. However, the links between individual motility and the processes that generate and maintain microbial diversity are poorly understood. Movement ecology is a framework linking the physiological and behavioral properties of individuals to movement patterns across scales of space, time, and biological organization. By synthesizing insights from cell biology, ecology, and evolution, we expand theory from movement ecology to predict the causes and consequences of microbial movements. Our mechanistic understanding of the machinery that powers microbial motility has advanced considerably alongside mounting evidence from the ecological literature that dispersal plays a key role in structuring patterns of microbial biodiversity. Despite the parallel developments in these fields, they have focused largely on microbial movement at different scales, hindering the cross-scale integration from individual motility behavior to the dynamics of populations and communities. Movement ecology is a recent framework that could provide a means to integrate across these different perspectives to better understand microbial movement and explicitly identify the fundamental features of movement. Empirical studies using novel techniques have revealed important ways that microorganisms can sense and move through different environments, unlocking the potential to study microbial motility at different scales from a movement ecology perspective. [ABSTRACT FROM AUTHOR]

Inulin is a typical kind of fermentable polysaccharide and has emerged as a promising dietary supplement due to its multiple health-promoting effects. This study aimed to unveil the dynamic change pattern of inulin utilizability as a fermentation substrate during gut microbiota development and illuminate its potential association with gut microbiota in Chinese Jinhua native pig models via longitudinal analyses. Herein, fresh feces were collected at one week pre- and post-weaning as well as 3rd month post-weaning, respectively. Targeted metabolomics and in vitro simulated fermentation revealed increasing concentrations of fecal short-chain fatty acids (SCFAs) and elevating utilizability of inulin as a fermentation substrate. Microbiomic analyses demonstrated the conspicuous longitudinal alteration in gut microbial composition and a significant rise in microbial community diversity during gut microbiota development. Furthermore, gut microbial functional analyses showed a remarkable increase in the relative abundances of carbohydrate metabolism pathways, including pentose phosphate pathway, galactose metabolism pathway, butanoate metabolism pathway as well as fructose and mannose metabolism pathway. Notably, relative abundances of bacterial genera Bifidobacterium , Roseburia , Faecalibacterium and Enterococcus displayed significantly positive correlations with the production of microbial fermentation-derived SCFAs. Collectively, these findings offer novel insights into understanding inulin utilizability variations from the perspective of gut microbiota development. [Display omitted] • Longitudinal observations demonstrate increasing concentrations of swine fecal SCFA. • In vitro fermentation assay reveals escalating utilizability of inulin as a substrate. • Microbiomic analyses show a longitudinal increase in swine gut microbial diversity. • Functional analyses show increasing abilities of microbial utilizing carbohydrates. • Dynamics of inulin utilizability correlate with longitudinal microbiota alterations. [ABSTRACT FROM AUTHOR]

Labneh Ambaris is a traditional Lebanese dairy product typically made using goat milk in special earthenware jars. Its production is characterized by the regular additions of milk and coarse salt, all while draining the whey throughout a process that lasts for a minimum of 2 mo. In this study, 20 samples of labneh Ambaris, all produced by spontaneous fermentation, were studied. They were collected at the end of fermentation from different regions in Lebanon. Physicochemical and sensory properties were studied and microbial diversity was analyzed using culture-dependent and independent techniques. The V3–V4 region of the 16S rRNA gene and the ITS2 region were sequenced by DNA metabarcoding analyses for the identification of bacteria and yeast communities, respectively. Out of 160 bacterial and 36 fungal taxa, 117 different bacterial species and 24 fungal species were identified among all labneh Ambaris samples studied. The remaining ones were multi-affiliated and could not be identified at the species level. Lactobacillus was the dominant bacterial genus, followed by Lentilactobacillus , Lactiplantibacillus , Lacticaseibacillus , and Lactococcus genera, whereas Geotrichum and Pichia were the dominant fungal genera. The 20 samples tested had varying levels of salt, protein, and fat contents, but they were all highly acidic (mostly having a pH < 4). According to the sensory scores generated by classical descriptive analysis, all samples were described as having basic similar characteristics such as goat smell and flavor, but they could be differentiated based on various intensities within the same descriptors like salty and acidic. This work could be considered as a base toward obtaining a quality label for labneh Ambaris. [ABSTRACT FROM AUTHOR]

[Display omitted] • We conducted a large-scale investigation of skin microbiota composition and diversity in BP. • We reveal substantial differences in skin microbiota in patients with BP compared to that of control subjects. • We observe a transitional stage between normal- and diseased skin within patients with BP. • BP is characterized by a loss of protective microbiota and an increase in S. aureus , an inflammation-promoting species. • S. aureus ubiquitously associates with BP, suggesting a role in pathogenesis. • Our results may help inform clinical markers for assessing BP disease risk and prognosis. Bullous pemphigoid (BP) is the most common autoimmune blistering disease. It predominately afflicts the elderly and is significantly associated with increased mortality. The observation of age-dependent changes in the skin microbiota as well as its involvement in other inflammatory skin disorders suggests that skin microbiota may play a role in the emergence of BP blistering. We hypothesize that changes in microbial diversity associated with BP might occur before the emergence of disease lesions, and thus could represent an early indicator of blistering risk. The present study aims to investigate potential relationships between skin microbiota and BP and elaborate on important changes in microbial diversity associated with blistering in BP. The study consisted of an extensive sampling effort of the skin microbiota in patients with BP and age- and sex-matched controls to analyze whether intra-individual, body site, and/or geographical variation correlate with changes in skin microbial composition in BP and/or blistering status. We find significant differences in the skin microbiota of patients with BP compared to that of controls, and moreover that disease status rather than skin biogeography (body site) governs skin microbiota composition in patients with BP. Our data reveal a discernible transition between normal skin and the skin surrounding BP lesions, which is characterized by a loss of protective microbiota and an increase in sequences matching Staphylococcus aureus, a known inflammation-promoting species. Notably, Staphylococcus aureus is ubiquitously associated with BP disease status, regardless of the presence of blisters. The present study suggests Staphylococcus aureus may be a key taxon associated with BP disease status. Importantly, we however find contrasting patterns in the relative abundances of Staphylococcus hominis and Staphylococcus aureus reliably discriminate between patients with BP and matched controls. This may serve as valuable information for assessing blistering risk and treatment outcomes in a clinical setting. [ABSTRACT FROM AUTHOR]

• Understanding the factors that can sustainably enhance soybean yield is critical. • Higher microbial diversity promoted less soybean damage by insect herbivores. • Soybean exhibits high tolerance to herbivory regardless of microbial diversity. • Promoting microbial diversity may promote a sustainable agricultural economy. Biodiversity within ecological communities has been shown to influence plant resistance and tolerance to herbivory, and may strongly interact with climate change. However, the effects of diversity within microbial symbionts on their plant hosts' responses to herbivores is less well documented, particularly within the context of agricultural systems. Here we examine the interactive effects of rhizobial diversity and drought in promoting soybean resistance and tolerance to insect and mammalian herbivores in an outdoor pot experiment. We demonstrate that soybean plants provided with a diverse mixture of rhizobial strains experience 30% less damage by chewing insect herbivores under both drought (reduced watering and increased temperature) and ambient weather conditions, as well as half as much colonization by aphids under drought conditions. This effect was not due to the presence of any particularly beneficial rhizobial strain (i.e. , not a selection effect), but rather due to an enhanced benefit provided by the rhizobial strains in combination (i.e. , a complementarity effect). No effects of rhizobial diversity were observed on the rate of defoliation by rabbits. While rhizobial diversity did affect soybean resistance to insect herbivores, these differences in insect damage did not carry through to affect soybean growth or final yield. Thus, soybean plants exhibited high tolerance to herbivory regardless of our experimentally imposed rhizobial diversity or drought treatments. With future projections for increased pest outbreaks and drought, understanding the factors that can sustainably enhance agricultural yield is critical. Our results suggest that promoting rhizobial diversity within soybean agriculture may be one nature-based solution to promote the resistance of this critical crop to insect pests. [ABSTRACT FROM AUTHOR]

Pyometra is a common and high-incidence reproductive system disease in female dogs, and its development involves both hormonal and bacterial factors. Characterization of the endometrial microbiome in healthy dogs and diseased dogs with pyometra remains unclear at present, however. In this study, dogs with pyometra were identified based on the clinical examinations, hematology examinations, vaginal smears and uterine histopathology. The endometrial samples of healthy dogs (n = 30) and diseased dogs (n = 41) were then collected and sequenced by 16S rRNA high-throughput sequencing technology. Dogs with pyometra suffered from inflammation, and their endometrial microbial diversity (ACE and Chao 1 indices) was significantly lower than that of healthy dogs (P < 0.05). The endometrial samples of both groups were enriched in four phyla (Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria), with a greater abundance of Firmicutes in diseased dogs (P < 0.05). At the genus level, the most prevalent microbes in diseased dogs belonged to Pseudomonas, Escherichia-Shigella, Mycoplasma, Enterococcus, Haemophilus, Vibrio and Ralstonia , with lower levels of Mycoplasma, Enterococcus and Haemophilus in the healthy control. Principal co-ordinates analysis and non-metric multi-dimensional scaling showed that the endometrial microbiome of diseased dogs clustered separately from that of the healthy controls (P < 0.05). In the LDA effect size analysis, 18 members of the endometrial microbiome were screened. Of these, the bacterial species Pseudomonas_aeruginosa and microbes within the genera Mycoplasma, Enterococcus and Haemophilus were found to be enriched in the uteruses of diseased dogs. Furthermore, the Random Forests model further confirmed that Mycoplasma and Haemophilus could be considered as biomarkers of diseased endometrium. In conclusion, this study provided a theoretical basis for the development of probiotic preparation in the future. • The endometrial microbial diversity in dogs with pyometra was significantly lower than that of healthy dogs. • A species bacteria Pseudomonas_aeruginosa and the genus microbiota Mycoplasma, Enterococcus and Haemophilus might be used as a biomarker for the early diagnosis of canine pyometra. [ABSTRACT FROM AUTHOR]

Composting is a common practice used for treating animal manures before they are used as organic fertilizers for crop production. Whether composting can effectively reduce microbial pathogens and antibiotic resistance genes remain poorly understood. In this study, we compared 3 different dairy manure composting methods—anaerobic fermentation (AF), static compost (SC), and organic fertilizer production (OFP)—for their effects on antibiotic-resistant bacteria, antibiotic resistance genes, and microbial community diversity in the treated manures. The 3 composting methods produced variable and distinct effects on antibiotic-resistant bacteria, zoonotic bacteria, and resistance genes, some of which were decreased and others of which showed no significant changes during composting. Particularly, SC and OFP reduced chloramphenicol resistance gene fexA and opportunistic pathogen Vibrio fluvialis , whereas AF significantly reduced tetracycline resistance gene tetB and opportunistic pathogens Enterococcus faecium and Escherichia fergusonii. The compositions of microbial communities varied significantly during the composting processes, and there were significant differences between the 3 composting methods. In all 3 composts, the dominant phyla were Firmicutes , Proteobacteria , Bacteroidetes , and Actinobacteria. Interestingly, Firmicutes , Proteobacteria , and Bacteroidetes remained stable in the entire AF process, whereas they were dominated at the beginning, decreased at the early stage of composting, and rebounded at the later stage during SC and OFP. In general, SC and OFP produced a more profound effect than AF on microbial community diversities, pathogens, and dominant species. Additionally, Enterococcus aquimarinus was isolated from AF for the first time. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States function prediction analysis indicated that the genes related to membrane transport and amino acid metabolism were abundant in the 3 composts. The metabolism of amino acids, lipids, and carbohydrates increased as composting progressed. The biosynthesis of antibiotics was enhanced after fermentation in the 3 composting methods, and the increase in the SC was the most obvious. These results reveal dynamic changes in antibiotic-resistant bacteria, antibiotic resistance genes, microbial community composition, and function succession in different dairy manure composts and provide useful information for further optimization of composting practices. [ABSTRACT FROM AUTHOR]

Biotrickling filters (BTFs) for volatile organic compounds (VOCs) have attracted tremendous research attention in the field of environmental engineering. However, the problem of clogging occurred during the long-term operation limits their practical applications. To alleviate the clogging, an integral polypropylene (PP) packing coated with polydimethylsiloxane (PDMS) was prepared, and in combination with fungus, its performance was investigated for toluene elimination. Two laboratory-scale BTFs were started at low toluene concentrations of 200–900 mg · m−3. Subsequently, a series of experiments were conducted at toluene concentrations of 47–2906 mg · m−3, with empty bed residence time (EBRT) values of 50 and 40 s. Toluene removal efficiency reached 100 % at the inlet toluene concentration of 296–560 mg∙m−3 for EBRT of 50 s. The maximum elimination capacity (EC) of 98 g∙m−3∙h−1 was obtained at an inlet toluene load of 117.67 g∙m−3∙h−1. Clogging was relieved by manual cleanup, and the BTFs were operated steadily for nearly 8 months. CO 2 production was monitored during the whole operation, and toluene mineralization was evaluated simultaneously. Furthermore, the biofilm structure and microbial diversity were analyzed. [Display omitted] [ABSTRACT FROM AUTHOR]

• Co-digesting swine manure and waste kitchen oil allowed OLR up to 6 g VS/L/d. • A reasonable amount of oil increased biogas yield and bacterial alpha-diversity. • System imbalance occurred when oil was added beyond certain threshold. • "Inhibited steady state" phenomenon was observed at high OLRs. • Up to three months were needed to confirm system failure for middle to high OLRs. Anaerobic co-digestion of swine manure (SM) and waste kitchen oil (WKO) was conducted to evaluate the effect of high organic loading rates (OLRs) on biogas production efficiency and microbial changes. Combinations of different loading rates of SM and WKO, with total OLRs from 2 to 8 g VS (volatile solid)/L/d, were evaluated in a laboratory-scale study. While feeding more than 4 g VS SM /L/d did not result in higher biogas production in both mono- and co-digestion scenarios, the addition of WKO increased the total OLR up to 6 g VS/L/d without significant reduction of system productivity. Biogas yields of M2O1 (2 g VS SM /L/d + 1 g VS WKO /L/d) and M4O2 were 910 ± 35 and 849 ± 85 mL/g VS fed which were 25.2 % and 16.9 % higher than the mono-digestion of M2, respectively. A significant increase of bacterial alpha-diversity (Shannon index) was observed in M2O1, at 233.0 ± 3.6 compared with 218.7 ± 5.1 of M2 (p < 0.05). Less bacterial alpha-diversity and accumulation of volatile fatty acids were observed in M4O1 and M4O2, suggesting their potential instability. When digesters were fed with M2, the introduction of 1.4 g VS WKO /L/d or more did not increase biogas yield and could cause system imbalance. The study suggests the limit of WKO could be increased when higher OLRs of SM were applied but should not be more than 4 g VS SM /L/d, and ratio between SM and WKO should be considered to avoid failure. Some of the system disturbances took up to three months to show. [ABSTRACT FROM AUTHOR]