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Soil microbial communities are essential drivers of ecosystem functions, yet the factors shaping their structure and function, particularly at different altitudes and between invasive and native plants, remain insufficiently understood. Using high-throughput Illumina sequencing, we assessed the composition, diversity, impact factors, and functional potential of the microbial communities associated with Galinsoga quadriradiata (an invasive species) and Artemisia lavandulifolia (a native species) across an altitudinal gradient ranging from 896 m to 1889 m in the Qinling Mountains. The results revealed that both plant species and altitude significantly influenced soil bacterial diversity and community structure. Actinobacteriota, Proteobacteria, and Acidobacteriota accounted for higher proportions in the soils of G. quadriradiata and A. lavandulifolia. A linear discriminant analysis showed that the two species hosted distinct microbial communities, with variations driven by species-specific traits and environmental factors. Compared with plant parameters, environmental factors had a greater impact on plant soil bacterial abundance. Functional analysis indicated that A. lavandulifolia soils were more associated with nitrogen cycling processes, while G. quadriradiata soils contributed more to organic matter decomposition. Therefore, invasive and native plants harbored microbial flora with different nutritional preferences and metabolic characteristics. These findings advance our understanding of plant–microbe interactions along altitudinal gradients, and they have practical implications for managing invasive species and supporting ecosystem resilience. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) has been detailed to affect soil microbial exercises or community composition. There is a lack of information on the degree to which PGPR as a biofertilizer concurrently influences the action, estimate, and composition of the soil microbial community. This research investigated the impacts of the timing and frequency of PGPR application as biofertilizers on the rhizosphere bacteria community in arable soil. We compared four treatments in an experimental field site, namely: one-time treatment of PGPR at the beginning of planting (P1), twice treatment of PGPR (P2), 15-days of planting (DP), and 30-DP (P3); and without treatment of PGPR (WP). A total rhizosphere bacteria community fingerprint was surveyed using ribosomal intergenic spacer analysis (RISA) using a culture-dependent and culture-independent approach. The rhizosphere bacteria community was surveyed during 80 DP. The unweighted pair-group method with arithmetic mean (UPGMA) clustering showed that the rhizosphere bacteria community in three-frequency applications of PGPR was more abundant than without PGPR application and one or two PGPR applications. This study revealed that the rhizosphere bacteria community was increased in soil with PGPR application, especially in P3, three dosages of PGPR application. Increasing the rhizosphere bacteria community could strongly influence the clay foam soil nutrient.

The application of biochar can effectively enhance soil organic matter (SOM) and improve soil structure. Biomass power plant ash (BPPA) is also rich in essential nutrients for plants, with similar carbon content. Considering production cost and agricultural waste recycling, it is beneficial to apply BPPA to improve soil fertility and quality. However, it remains unclear whether its ameliorative effects surpass those of biochar in alkaline soils. In the study, we set up seven pot experiments of faba beans in sandy alkaline soils from the ancient region of the Yellow River, including the controls (CK), different amounts of acid-modified BPPA (A1, A2, A3), and the same amounts of acid-modified biochar (B1, B2, B3), to compare their effects on soil physiochemical properties and bacterial community structure. The results indicate that the application of both biochar and BPPA can improve soil physiochemical properties. At the same dosage, the biochar application outperformed BPPA treatment in terms of soil physical properties such as bulk density (BD), maximum water-holding capacity (FC), and soil capillary porosity (SP2). Conversely, BPPA treatment displayed advantages in chemical properties such as readily oxidizable organic carbon (ROOC), total nitrogen (TN), alkaline nitrogen (AN), available phosphorus (AP), available potassium (AK), and electrical conductivity (EC). All the treatments enhanced the richness and diversity of bacterial communities, increasing the relative abundance of eutrophic groups such as Bacteroidota and Firmicutes while decreasing that of oligotrophic groups like Actinobacteriota. BPPA also increased the relative abundance of Proteobacteria, while the opposite was observed for biochar. Correlation analysis showed that the environmental factors such as soil pH, EC, TN, AK, SOM, and SP2 emerged as primary factors influencing the bacterial community structure of alkaline soils, significantly affecting their diversity and abundance. Among them, SP2 and SOM were the dominant physical and chemical factors, respectively. Overall, the application of both acid-modified BPPA and biochar can enhance the physiochemical properties of sandy alkaline soils, while the application of BPPA is superior for improving soil nutrient content and enhancing bacterial community structure. The study explores the potential mechanisms through which the application of acid-modified BPPA affects soil characteristics and microbial features, providing new insight into developing optimizing fertilization strategies for enhancing soil quality in the ancient region of the Yellow River. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPR) has been detailed to affect soil microbial exercises or community composition. There is a lack of information on the degree to which PGPR as a biofertilizer concurrently influences the action, estimate, and composition of the soil microbial community. This research investigated the impacts of the timing and frequency of PGPR application as biofertilizers on the rhizosphere bacteria community in arable soil. We compared four treatments in an experimental field site, namely: one-time treatment of PGPR at the beginning of planting (P1), twice treatment of PGPR (P2), 15-days of planting (DP), and 30-DP (P3); and without treatment of PGPR (WP). A total rhizosphere bacteria community fingerprint was surveyed using ribosomal intergenic spacer analysis (RISA) using a culture-dependent and culture-independent approach. The rhizosphere bacteria community was surveyed during 80 DP. The unweighted pairgroup method with arithmetic mean (UPGMA) clustering showed that the rhizosphere bacteria community in three-frequency applications of PGPR was more abundant than without PGPR application and one or two PGPR applications. This study revealed that the rhizosphere bacteria community was increased in soil with PGPR application, especially in P3, three dosages of PGPR application. Increasing the rhizosphere bacteria community could strongly influence the clay foam soil nutrient. [ABSTRACT FROM AUTHOR]

The effects of salinity gradients (500–4000 mg·L−1 NaCl) on electricity generation, nitrogen removal, and microbial community were investigated in a constructed wetland-microbial fuel cell (CW-MFC) system. The result showed that power density significantly increased from 7.77 mW m−2 to a peak of 34.27 mW m−2 as salinity rose, indicating enhanced electron transfer capabilities under saline conditions. At a moderate salinity level of 2000 mg·L−1 NaCl, the removal efficiencies of NH4+–N and TN reached their maximum at 77.34 ± 7.61% and 48.45 ± 8.14%, respectively. This could be attributed to increased microbial activity and the presence of critical nitrogen-removal organisms, such as Nitrospira and unclassified Betaproteobacteria at the anode, as well as Bacillus, unclassified Rhizobiales, Sphingobium, and Simplicispira at the cathode. Additionally, this salinity corresponded with the highest abundance of Exiguobacterium (3.92%), a potential electrogenic bacterium, particularly at the cathode. Other microorganisms, including Geobacter, unclassified Planctomycetaceae, and Thauera, adapted well to elevated salinity, thereby enhancing both electricity generation and nitrogen removal. [ABSTRACT FROM AUTHOR]

The problem of antibiotic resistance genes (ARGs) caused by heavy metals has attracted extensive attention of human beings. Zn, a widely used feed additive, has a very high residue in swine manure, but the distribution characteristics of ARGs imposed by Zn in anaerobic digestion (AD) products are not clear. In this study, the behaviour of mobile genetic elements (MGEs), bacterial community, and their association with ARGs were determined in the presence of 125 and 1250 mg L–1 Zn in AD system of swine manure. Zn-treated enriched the abundance of ARGs, and produced some new genotypes that were not detected in CK treatment. In addition, low concentration of Zn significantly increased the relative abundance of ARGs, as compared to higher Zn and CK group. Correspondingly, the abundances of most top30 genus were highest in ZnL (125 mg L–1 Zn), followed by CK and ZnH (1250 mg L–1 Zn). Notably, network analysis showed that the relationship between ARGs and MGEs is closer than that ARGs and bacteria, suggesting that ARGs increased in Zn-treated, especially low level Zn, may be due to the amplification transfer of ARGs among varied microorganisms by horizontal transfer with MGEs. Therefore, strengthen the management of in livestock manure is crucial to control the spread of ARGs in organic fertilizers. [ABSTRACT FROM AUTHOR]

Compared with typical Earth soil, Martian soil and Mars simulant soils have distinct properties, including pH > 8.0 and high contents of silicates, iron-rich minerals, sulfates, and metal oxides. This unique soil matrix poses a major challenge for extracting microbial DNA. In particular, mineral adsorption and the generation of destructive hydroxyl radicals through cationic redox cycling may interfere with DNA extraction. This study evaluated different protocols for extracting microbial DNA from Mars Global Simulant (MGS-1), a Mars simulant soil. Two commercial kits were tested: the FastDNA SPIN Kit for soil ("MP kit") and the DNeasy PowerSoil Pro Kit ("PowerSoil kit"). MGS-1 was incubated with living soil for five weeks, and DNA was extracted from aliquots using the kits. After extraction, the DNA was quantified with a NanoDrop spectrophotometer and used as the template for 16S rRNA gene amplicon sequencing and qPCR. The MP kit was the most efficient, yielding approximately four times more DNA than the PowerSoil kit. DNA extracted using the MP kit with 0.5 g soil resulted in 28,642–37,805 16S rRNA gene sequence reads and 30,380–42,070 16S rRNA gene copies, whereas the 16S rRNA gene could not be amplified from DNA extracted using the PowerSoil kit. We suggest that the FastDNA SPIN Kit is the best option for studying microbial communities in Mars simulant soils. [ABSTRACT FROM AUTHOR]

ABSTRACT Skeletonema costatum, a cosmopolitan diatom primarily inhabiting coastal ecosystems, exhibits a typically close yet variable relationship with heterotrophic bacteria. The increasing temperature of surface seawater is expected to substantially affect the viability and ecological dynamics of S. costatum, potentially altering its relationship with bacteria. However, it remains unclear to what extent the elevated temperature could change these relationships. Here, the relationship between axenic S. costatum and natural seawater bacteria underwent a dramatic shift from mutualism to antagonism as the co-culture temperature increased from 20°C to 25°C. The co-occurrence network indicated significantly increased complexity of interaction between S. costatum and bacteria community after temperature elevation, especially with Flavobacteriaceae, implying their potential role in eliminating S. costatum under higher temperatures. Additionally, a Flavobacteriaceae isolate, namely MS1 identified as Tamlana genus, was isolated from the co-culture system at 25°C. MS1 had a remarkable ability to eliminate S. costatum, with the mortality rate at 25°C steadily rising from 30.2% at 48 h to 92.4% at 120 h. However, it promoted algal growth to some extent at 20°C. These results demonstrated that increased temperature promotes MS1 shifts from mutualism to antagonism with S. costatum. According to the comparative genomics analysis, changes in the lifestyle of MS1 were attributed to the increased gliding motility and attachment of MS1 under elevated temperature, enabling it to exert an algicidal effect through direct contact with alga. This investigation provided an advanced understanding of interactions between phytoplankton and bacteria in future warming oceanic ecosystems.IMPORTANCEOcean warming profoundly influences the growth and metabolism of phytoplankton and bacteria, thereby significantly reshaping their interactions. Previous studies have shown that warming can change bacterial lifestyle from mutualism to antagonism with phytoplankton, but the underlying mechanism remains unclear. In this study, we found that high temperature promotes Tamlana sp. MS1 adhesion to Skeletonema costatum, leading to algal lysis through direct contact, demonstrating a transition in lifestyle from mutualism to antagonism with increasing temperature. Furthermore, the gliding motility of MS1 appears to be pivotal in mediating the transition of its lifestyle. These findings not only advance our understanding of the phytoplankton-bacteria relationship under ocean warming but also offer valuable insights for predicting the impact of warming on phytoplankton carbon sequestration.

The goal of this study was to investigate the bacterial community associated with biogas production from food waste and rumen content. Anaerobic mono-digestion and co-digestion were performed using mixture design within Design Expert, resulting in 100 experimental runs. Parameters such as food waste and rumen content, water content, temperature, pH, number of digester agitation per day and retention time were varied during the anaerobic digestion processes. Classical microbiological techniques were used to isolate and identify strict anaerobic and facultative anaerobic bacteria from the food waste and rumen content before and after anaerobic digestion. Sixteen bacterial species belonging to 12 different generae were isolated and identified from the food waste, rumen content and composite digestates obtained from the 100 bio-digesters. These generae included Acetobacterium, Bacteroides, Clostridium, Enterobacter, Escherichia, Lactobacillus, Pseudomonas, Ruminococcus, Staphylococcus, Streptococcus, Syntrophomonas and Syntrophobacter. With the exception of Escherichia coli and Pseudomonas sp., all other bacterial species identified in the substrates were also found in samples of the composite digestates, suggesting that they may have played important roles in the anaerobic digestion process inside the 100 bio-digesters. Overall, this study provides valuable insights into the microbial community structure and function during biogas production from food waste and rumen content. The results could contribute to the development of more efficient and sustainable biogas production processes.

Saline–alkali soils seriously restrict the soil functions and the growth and diversity of soil microorganisms. Biochar can alleviate the negative effects of saline–alkali stress. However, it remains unclear how biochar reduces saline–alkali stress by improving soil functions and regulating the abundance and diversity of the soil bacterial community in highly saline–alkali paddy fields. To address this, a paddy field experiment was conducted in a highly saline–alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates (0, 1.5%, 3.0%, and 4.5% biochar, w/w). The results show that, compared with C0, biochar application, especially when combined with N fertilizer, significantly decreased the soil pH, exchangeable sodium percentage (ESP), saturated paste extract (ECe), and sodium adsorption ratio (SAR) while significantly increasing cation exchange capacity (CEC). These indicated that biochar can effectively reduce saline–alkali stress. Biochar application significantly increased soil content of total nitrogen (TN), alkali-hydrolysable N (AN), available P (AP), available K (AK), soil organic matter (SOM), and soil C/N ratio, both with or without N fertilization. Furthermore, biochar application further increased the relative abundance of bacterial communities and modified the bacterial community structure in highly saline–alkali paddy soils. Under C3N2, C2N2, and C1N2, Chao1 increased by 10.90%, 10.42%, and 1.60% compared to C0N2. Proteobacteria, Bacteroidetes, and Chloroflexi were the top three phyla in bacterial abundance. Biochar significantly increased the abundance of Proteobacteria while reducing Bacteroidetes and Chloroflexi, regardless of N fertilization. Correlation analysis results showed that the improvements in soil chemical and saline–alkali properties, as well as nutrient bioavailability after biochar application, had a positive effect on bacterial communities in highly saline–alkali paddy soils. [ABSTRACT FROM AUTHOR]

As the global human population continues to increase, the use of saline–alkali land for food production is an important consideration for food security. In addition to breeding or cultivating salt-tolerant crop varieties, microorganisms are increasingly being evaluated for their ability to improve plant salt tolerance. Barley is one of the most important and salt-tolerant cereal crops and is a model system for investigating the roles of microorganisms in improving plant salt tolerance. However, a comprehensive review of the mechanisms by which microorganisms improve barley salt tolerance remains lacking. In this review, the mechanisms of barley salt tolerance improvement by microorganisms are summarized, along with a discussion of existing problems in current research and areas of future research directions. In particular, with the development of sequencing technology and the great reduction of prices, the use of omics can not only comprehensively evaluate the role of microorganisms but also evaluate the impact of the microbiome on plants, which will provide us with many opportunities and challenges in this research area. [ABSTRACT FROM AUTHOR]

Root-associated bacteria play a vital role in the soil ecosystem and plant productivity. Previous studies have reported the decline of bacterial community and rhizosphere soil quality in the cultivation of some medicinal plants (i.e., Pseudostellaria heterophylla). Phosphorus (P)-modified biochar has the potential to improve soil health and quality. However, its influence on the bacterial community and diversity in the rhizosphere of medicinal plants is not well understood. Therefore, this study aims to investigate the effects of P-modified biochar on the bacterial community and diversity in the rhizosphere of P. heterophylla. Soil samples were collected from the rhizosphere of 4-month P. heterophylla under control (no biochar), 3% unmodified and 3% P-modified biochar treatments, respectively. Compared with control and unmodified biochar treatment, P-modified biochar significantly increased the relative abundance of plant-beneficial bacteria (P < 0.05), particularly Firmicutes, Nitrospirae and Acidobacteria. The relative abundance of Bacillus, belonging to Firmicutes, was dramatically raised from 0.032% in control group to 1.723% in P-modified biochar-treated group (P < 0.05). These results indicate the potential enhancement of soil quality for the growth of medicinal plants. The application of biochar significantly increased bacterial richness and bacterial diversity (P < 0.05). P modification of biochar did not have significant effects on soil bacterial richness (P > 0.05), while it reduced Shannon and increased Simpson diversity index of soil bacterial communities significantly (P < 0.05). It indicates a decrease in bacterial diversity. This research provides a new perspective for understanding the role of P-modified biochar in the rhizosphere ecosystem. [ABSTRACT FROM AUTHOR]

Based on the low content of water-soluble carbohydrate (WSC) and lactic acid bacteria (LAB) attachment in oat raw materials, we assumed that the neutral detergent fiber (NDF) content of oat can be reduced by adding cellulase or xylanase. The concentration of metabolizable sugars will be increased, which will assist the oat's bacterial community in fermentation and obtain a better quality of oat silage. After wilting the oat, it was treated as follows: (1) distributed water (CK); (2) silages inoculated with xylanase (X); and (3) silages inoculated with cellulase (C), ensiling for 3, 7, 14, 30, and 60 days. Cellulase and xylanase treatments both alter the fermentation and nutritional quality of ensiled oat, resulting in lower NDF, acid detergent fiber (ADF), cellulose, and hemicellulose contents, increased lactic acid and acetic acid contents, and a significant decrease in ensiling environment pH. The bacterial community undergoes significant changes with cellulase and xylanase treatments, with a significant increase in Lactobacillus abundance in the C_14, X_30, C_30, X_60, and C_60 treatment groups, while Weissella abundance gradually decreases with longer ensiling times. Two exogenous fibrolytic enzymes also alter the bacterial diversity of ensiled oat, with different bacterial species and abundances observed in different treatment groups. Ensiled oat treated with cellulase and xylanase experiences significant changes in its own bacterial community, particularly in the abundance of Lactobacillus. These changes result in improved fermentation and nutritional quality of oat, but the higher metabolism levels observed after 60 days of ensiling with cellulase treatment may lead to energy loss. [ABSTRACT FROM AUTHOR]

Pharmaceutical usage has led to the widespread detection of these compounds in aquatic ecosystems worldwide, raising concerns about the selective pressure they can exert on microbial communities. To aid in tackling this global emergency, we undertook an initial step in identifying potential hotspots of bacterial resistance arising from the occurrence of antibiotics in the environment. This was conducted by performing a risk assessment based on the measured environmental concentrations of selected antibiotics, acquired from an international pharmaceutical database, and the respective no-effect concentrations for bacterial resistance of such antibiotics. We identified untreated industrial and hospital sewage as the aquatic matrices of most concern. Regarding treated effluent from wastewater treatment plants, the antibiotic ciprofloxacin and Tunisia exhibit a high-risk quotient. For surface water matrices (rivers and streams), both ciprofloxacin and amoxicillin warrant attention and the countries with the highest risk medians were India, South Africa, and the United States of America. Our study provides an initial basis for highlighting the antibiotics, countries, and aquatic matrices that warrant more attention regarding bacterial resistance. This approach can be applied at national or regional scales for more detailed environmental evaluation and decision-making. Nonetheless, we encourage further investigations to confirm the occurrence of antibiotic-resistant bacteria and antibiotic-resistance genes in the potential hotspots identified in this study.

Raw camel milk is generally contaminated with varied microbiota, including antibiotic–resistant bacteria (ARB), that can act as a potential pathway for the spread of antibiotic resistance genes (ARGs). In this study, high–throughput quantitative PCR and 16S rRNA gene–based Illumine sequencing data were used to establish a comprehensive understanding of the antibiotic resistome and its relationship with the bacterial community in Bactrian camel milk from Xinjiang. A total of 136 ARGs and up to 1.33 × 108 total ARG copies per gram were identified, which predominantly encode resistance to β–lactamas and multidrugs. The ARGs' profiles were mainly explained by interactions between the bacteria community and physicochemical indicators (77.9%). Network analysis suggested that most ARGs exhibited co–occurrence with Corynebacterium, Leuconostoc and MGEs. Overall, raw camel milk serves as a reservoir for ARGs, which may aggravate the spread of ARGs through vertical and horizontal gene transfer in the food chain. [ABSTRACT FROM AUTHOR]

This study investigated the performance of thermophilic–mesophilic (T-M) and mesophilic–thermophilic (M-T) two-phase sludge anaerobic digestion at different inoculation proportions after a change in digestion temperature. After temperature change, the pH, total ammonia nitrogen (TAN), free ammonia nitrogen (FAN), solubility chemical oxygen demand (SCOD), and total alkalinity (TA) levels of two-phase digesters were between thermophilic control digesters and mesophilic control digesters. However, the volatile fatty acid (VFA) levels of two-phase digesters were higher than those of thermophilic or mesophilic control digesters. The bacteria communities of M-T two-phase digesters were more diverse than those of T-M. After a change in digestion temperature, the bacterial community was dominated by Coprothermobacter. After a change of digestion temperature, the relative abundance (RA) of Methanobacterium, Methanosaeta, and Methanospirillum of M-T two-phase digesters was higher than that of T-M two-phase digesters. In comparison, the RA of Methanosarcina of T-M two-phase digesters was higher than that of M-T two-phase digesters. The ultimate methane yields of thermophilic control digesters were greater than those of mesophilic control digesters. Nevertheless, the ultimate methane yield levels of M-T two-phase digesters were greater than those of T-M two-phase digesters. The ultimate methane yields of all two-phase digesters presented an earlier increase and later decrease trend with the increasing inoculation proportion. Optimal methane production condition was achieved when 15% of sludge (T-M15) was inoculated under mesophilic–thermophilic conditions, which promoted 123.6% (based on mesophilic control) or 27.4% (based on thermophilic control). An optimal inoculation proportion (about 15%) balanced the number and activity of methanogens of high-solid sludge anaerobic digestion. [ABSTRACT FROM AUTHOR]

The microorganisms that inhabit the gastrointestinal tract are responsible for multiple chains of reactions that affect their environment and modify the internal metabolism, their study receives the name of microbiome, which has become more relevant in recent years. In the near future, the challenges related to feeding are anticipated to escalate, encompassing the nutritional needs to sustain an overpopulated world. Therefore, it is expected that a better understanding of the interactions between microorganisms within the digestive tract will allow their modulation in order to provide an improvement in the immune system, feed efficiency or the promotion of nutritional characteristics in production animals, among others. In the present study, the main effects of experimental diets in production animals were described, emphasizing the diversity of the bacterial populations found in response to the diets, ordering them between polygastric and monogastric animals, and then describing the experimental diets used and their effect on the microorganisms. It is hoped that this study will help as a first general approach to the study of the role of the microbiome in production animals under different diets. [ABSTRACT FROM AUTHOR]

AbstractThe richness and diversity of bacterial community in the fermented pit mud from the new and old distilleries of Shedian Liquor were analysed via the Illumina Miseq PE300 high-throughput sequencing technology, so as to further understand the differences of bacterial community structure in fermented pit muds with different pit ages. The results show that the bacterial community is mainly distributed into five dominant phyla (> 1.0%): Firmicutes, Synergistes, Bacteroidetes, Proteobacteria and Verrucomicrobia. There are 13 dominant genera (> 1.0%), of which Lactobacillus is dominant in both samples with a higher content in the new pit (61.12%) and lower in the old pit (1.15%). Caproiciproducens accounting for 43.53% and Syntrophomonas accounting for 6.20%, norank_f__Family_XIV (17.68%), Aminobacterium (17.68%), Sedimentibacter (1.89%), Caldicoprobacter (1.52%) and Sporanaerobacter (1.29%) are the dominant bacteria in the old pit mud. Bacillus accounting for 6.02%, Bacteroides (6.27%), Akkermansia (1.51%), Hydrogenispora (2.15%) and norank_f__Bacteroidales_S24-7_group (1.15%) are the dominant bacteria in the new pit mud. The results showed that there is a great difference in the bacterial community structure of in the new and old pit mud. In addition, compared with the bacterial community composition in the pit mud of Luzhou flavour Baijiu in Sichuan, it was found that the microorganisms that formed caproic acid and butyric acid were different.

Most oat forage has low water-soluble carbohydrates (WSC), which may be the main limited factor for silage fermentation safely, but oat is rich in cellulose and hemicellulose; therefore, we assume that xylanase and cellulase as additives can reduce the content of cellulose and xylan in oat silage, increase the microbial fermentable sugar content, and improve the fermentation quality of the silage. After wilting, oats were treated as follows: (i) distributed water (CK); (ii) silages inoculated with xylanase (X); (iii) silages inoculated with cellulase (C), ensiling for 3 days (early stage of silage) and 60 days (late stage of silage), respectively, after ensiling 60 days for a 5-day aerobic exposure study. The pH, neutral detergent fiber (NDF), and acid detergent fiber (ADF) were significantly reduced by xylanase and cellulase treatment during the late stage of silage, and the concentration of lactic acid, acetic acid, and ammonia nitrogen increased remarkably. The WSC content reached its peak with xylanase treatment during the late stage of silage. The content of crude protein (CP) was not affected by additives but by the silage period; CP and ether extract (EE) significantly increased during the late stage of silage compared to the early stage. After ensiling, the bacterial community showed that xylanase and cellulase treatment increased the relative abundance of lactic acid bacteria. Lactobacillus has a higher relative abundance with cellulase treatment after 60 days of ensiling; this can effectively reduce the pH of silage and ensure long-term, stable storage of silage. Cellulase and xylanase increased bacterial diversity during aerobic exposure and improved the aerobic stability of silage significantly. This study indicated that different additives and silage periods had significant effects on chemical compositions, fermentation quality, and bacterial community; meanwhile, both additives improved the aerobic stability of silage. In summary, when the WSC of oat is low, cellulase and xylanase have good effects as silage additives, and the comprehensive effect of cellulase is more prominent. [ABSTRACT FROM AUTHOR]

Recent studies have highlighted associations between diseases and host microbiota. It remains extremely challenging – especially under natural conditions – to clarify whether host microbiota promote future infections, or whether changes in host microbiota result from infections. Nonetheless, deciphering between these two processes is essential for highlighting the role of microbes in disease progression. We longitudinally surveyed, in the wild, the microbiota of individual fish hosts (Leuciscus burdigalensis) both before and after infection by a crustacean ectoparasite (Tracheliastes polycolpus). We found a striking association between parasite infection and the host microbiota composition restricted to the fins the parasite anchored. We clearly demonstrated that infections by the parasite induced a shift in (and did not result from) the host fin microbiota. Furthermore during infection, the microbiota of infected fins got similar to the microbiota of the adult stage, and the free‐living infective stage of the parasite with a predominance of the Burkholderiaceae bacteria family. This suggests that some Burkholderiaceae bacteria are involved in a coinfection process and possibly facilitate T. polycolpus infection. In this study, we reveal novel mechanistic insights for understanding the role of the microbiota in host–parasite interactions, which has implications for predicting the progression of diseases in natural host populations. [ABSTRACT FROM AUTHOR]

The lack of available phosphorus (P) in red soil severely limits the high yield of sugarcane. This study aims to explore the effects of different fertilization methods on P forms and bacteria community and the role of soil bacteria in P transformation in the seedling stage of sugarcane. Five fertilization treatments were set: no fertilizer (CK), a single application of chemical fertilizer (F), and combined application of chemical fertilizer with molasses (FC): the amount of added molasses (mg C kg−1 soil) was 64 (FC1), 160 (FC2), and 240 (FC3). Compared with F, FC treatment increased the sugarcane dry biomass, soil organic matter (SOM), pH, soluble organic P (Po) and stable inorganic P (Pi) contents while decreased the stable Po contents. All the F and FC treatments decreased the Shannon index compared with CK, whereas FC2 increased the Chao1 index and observed species. Proteobacteria, Chloroflexi, and Actinobacteria were the dominant taxa in all five treatments, where the relative abundances of Firmicutes and WPS-2 were higher in F than in FC. The increases in Bacillus and Sinomonas were accompanied by the depletion of soil stable Po. Redundancy analysis (RDA) revealed that pH and AP levels were significantly related to the bacterial community structure. Besides, the relative abundances of Bacillus plus Sinomonas were positively correlated with sugarcane dry biomass. These findings indicated that combined application of chemical fertilizer with moderate molasses can increase the sugarcane biomass and promote the utilization of soil stable Po via altering bacteria community and soil properties. [ABSTRACT FROM AUTHOR]

Nettle (Urtica cannabina) is an excellent feed resource widely distributed worldwide. Phyllosphere microbes are important as they have living conditions similar to those of the above-ground parts of host plants. Exploring amino acids (AA) and microorganisms can further understand the growth of plants in different seasons. The present study investigated the content of AA and phyllosphere microbes' structure of nettle plants in different seasons. The results found that AA contents varied significantly with the season, such as alanine, aspartate, cysteine, glutamate, glycine, and methionine contents decreased significantly from spring to winter (p < 0.05), the contents of arginine, histidine, serine, and lysine were highest in summer (p < 0.05). The results suggested that the diversity of bacteria and fungi both increased during winter. During winter, Sphingomonas (relative abundance 25.22–28.45%) and Filobasidum (27.6–41.14%) became dominant. According to the redundancy analysis (RDA) of the correlation between AA and microbes, these two microbes were both the most important factors and showed a negative correlation with AA during winter. Thus, seasons could significantly affect the distribution of phyllosphere microbial communities on the nettle, especially in winter. According to the function prediction(PICRUS2 (KEGG pathway) and FUNGuild) results, the bacteria in the phyllosphere of U. cannabina mainly participated in metabolism. Pathogenic fungi were relatively high in autumn. The present study reveals the influence of seasonal change on the phyllosphere microbial community in U. cannabina. [ABSTRACT FROM AUTHOR]

Compared with typical Earth soil, Martian soil and Mars simulant soils have distinct properties, including pH > 8.0 and high contents of silicates, iron-rich minerals, sulfates, and metal oxides. This unique soil matrix poses a major challenge for extracting microbial DNA. In particular, mineral adsorption and the generation of destructive hydroxyl radicals through cationic redox cycling may interfere with DNA extraction. This study evaluated different protocols for extracting microbial DNA from Mars Global Simulant (MGS-1), a Mars simulant soil. Two commercial kits were tested: the FastDNA SPIN Kit for soil (“MP kit”) and the DNeasy PowerSoil Pro Kit (“PowerSoil kit”). MGS-1 was incubated with living soil for five weeks, and DNA was extracted from aliquots using the kits. After extraction, the DNA was quantified with a NanoDrop spectrophotometer and used as the template for 16S rRNA gene amplicon sequencing and qPCR. The MP kit was the most efficient, yielding approximately four times more DNA than the PowerSoil kit. DNA extracted using the MP kit with 0.5 g soil resulted in 28,642–37,805 16S rRNA gene sequence reads and 30,380–42,070 16S rRNA gene copies, whereas the 16S rRNA gene could not be amplified from DNA extracted using the PowerSoil kit. We suggest that the FastDNA SPIN Kit is the best option for studying microbial communities in Mars simulant soils.

Abstract The gut microbiome is essential for processing complex food compounds and synthesizing nutrients that the host cannot digest or produce, respectively. New model systems are needed to study how the metabolic capacity provided by the gut microbiome impacts the nutritional status of the host, and to explore possibilities for altering host metabolic capacity via the microbiome. Here, we colonized the nematode Caenorhabditis elegans gut with cellulolytic bacteria that enabled C. elegans to utilize cellulose, an otherwise indigestible substrate, as a carbon source. Cellulolytic bacteria as a community component in the worm gut can also support additional bacterial species with specialized roles, which we demonstrate by using Lactobacillus plantarum to protect C. elegans against Salmonella enterica infection. This work shows that engineered microbiome communities can be used to endow host organisms with novel functions, such as the ability to utilize alternate nutrient sources or to better fight pathogenic bacteria.

Chromium (Cr) pollution is the primary pollution problem of the soil in tannery. However, the effect of tanning chemicals on Cr migration in soil has not been clearly elucidated. Column leaching tests were designed in this study to reveal the transport and transformation of Cr from basic chromium sulfate (BCS) into soil and the effects of lime on Cr migration and transformation. The results showed that BCS was mainly leached out in the state of Cr(VI) after entering the soil, and the Cr concentration in leachate decreased with the increase of the bulking thickness of the BCS. Compared with the soil absent of lime, the concentration of total Cr in the leachate from soil with lime decreased by 8.80–88.1%. The proportions of Cr in the residual fraction were generally increased in the soil with lime, whereas other fractions were decreased. The presence of lime can reduce the migration and toxicity of BCS in soil to a certain extent. The analysis of soil bacterial community showed that the relative abundance of Proteobacteria increased significantly with the exposure to BCS and the Burkholderiaceae was the dominant bacteria family in the BCS contaminated soil. Understanding the mobility of BCS and lime and the bacterial community in BCS contaminated soil is conducive to the risk assessment of the tannery site. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) can form symbiosis with many plants and the effect of AMF on phytoremediation of heavy metal has been a hot topic. But the effects of AMF on pollutants and microbes in rhizosphere and non-rhizosphere soil are still scarce. Therefore, the effects of AMF on plant growth, Pb translocation, and bacteria community in rhizosphere and non-rhizosphere soils spiked with Pb were investigated. It was found that AMF could significantly increase the uptake of Pb by Paspalum notatum, and Pb content was about 11 to 197 times higher in the root than that in the leaves. Besides, concentration of soil exchangeable Pb was significantly reduced after plant cultivation, and application of AMF increased the reduction (the exchangeable Pb concentrations of Pb300M and Pb3000M in the rhizosphere were 26.3% and 23.6% lower than that of Pb300 and Pb3000, respectively). The reduction was generally higher in the rhizosphere soil than that in the non-rhizosphere soil. The amount of Pb uptake by plants only accounted for a small part (4.9–21.7%) of the soil decreased exchangeable Pb, irrespective of AMF application, and most of the original exchangeable Pb was transformed into stabilized forms. Although bacteria community exhibited some differences between rhizosphere and non-rhizosphere soils, PCoA analysis indicated that both AMF and Pb were stronger impact factors affecting the beta-diversity of soil bacteria community than rhizosphere. The results of this study can help to clarify the impacts of AMF on phytoremediation of heavy metal. [ABSTRACT FROM AUTHOR]

[Display omitted] • SiO 2 nanoparticles enhance nitrogen retention by regulating functional genes. • SiO 2 nanoparticles reduce the abundance of copA in compost products. • Firmicutes and C/N ratio are the factors affecting nitrogen functional genes. • SiO 2 nanoparticles are effective additives for aerobic composting. SiO 2 nanoparticles (SiO 2 NPs) are low-cost, environmentally friendly materials with significant potential to remove pollutants from complex environments. In this study, SiO 2 NPs were used for the first time as an additive in aerobic composting to enhance nitrogen retention and reduce the expression of copper resistance genes. The addition of 0.5 g kg−1 SiO 2 NPs effectively reduced nitrogen loss by 72.33 % by decreasing denitrification genes (nosZ , nirK , and napA) and increasing nitrogen fixation gene (nifH). The dominant factors affecting nitrification and denitrification genes were Firmicutes and C/N ratio. Additionally, SiO 2 NPs decreased copper resistance genes by 28.96 % − 37.52 % in compost products. Copper resistance genes decreased most in the treatment with 0.5 g kg−1 SiO 2 NPs. In summary, 0.5 g kg−1 SiO 2 NPs have the potential to reduce copper resistance genes and enhance nitrogen retention during aerobic composting, which may be used to improve compost quality. [ABSTRACT FROM AUTHOR]

In the process of wastewater treatment, biomass was typically subjected to variation of nutrient condition. This study investigated the effects of different nutrient condition on denitrification performance and bacterial communities. The results showed that under carbon-to-nitrogen ratio (C/N) was 4, denitrifying sludge (DS) exhibited excellent denitrification performance with influent nitrate (NO 3 --N) concentration in the range of 88.8 ± 9.04–297.5 ± 6.63 mg L−1, maintained total nitrogen removal efficiency (TNRE) of 98.1 ± 1.75 %. While, as influent NO 3 --N concentration reached 408.9 ± 9.56 mg L−1, the denitrification performance was inhibited, and this inhibition was reversible. Under appropriate substrate level (215.0 ± 13.01 mg L−1), the specific denitrification activity (SDA) elevated to 300 % of its original value. Additionally, under starvation stress, although the relative abundance of some starvation-resistant bacteria (such as Actinobacteriota and Lentimicrobium) increased, the TNRE decreased by 7.3 %. During the recovery phase, despite extracellular polymeric substances (EPS) promoted, the TNRE decreased to 78.3 ± 4.7 %. Starvation stress was less favorable to DS for activity recovery than that of feast condition. These findings contribute to elucidating the mechanisms for DS to respond of different nutrient condition. [Display omitted] • The optimal growth condition for DS were determined. • Overly high or low nutrient levels forced reduction of TNRE and SDA. • Severe starvation stress was detrimental to the recovery of DS activity. • The response mechanisms of DS to special nutrient condition were elucidated. [ABSTRACT FROM AUTHOR]

Based on the low content of water-soluble carbohydrate (WSC) and lactic acid bacteria (LAB) attachment in oat raw materials, we assumed that the neutral detergent fiber (NDF) content of oat can be reduced by adding cellulase or xylanase. The concentration of metabolizable sugars will be increased, which will assist the oat’s bacterial community in fermentation and obtain a better quality of oat silage. After wilting the oat, it was treated as follows: (1) distributed water (CK); (2) silages inoculated with xylanase (X); and (3) silages inoculated with cellulase (C), ensiling for 3, 7, 14, 30, and 60 days. Cellulase and xylanase treatments both alter the fermentation and nutritional quality of ensiled oat, resulting in lower NDF, acid detergent fiber (ADF), cellulose, and hemicellulose contents, increased lactic acid and acetic acid contents, and a significant decrease in ensiling environment pH. The bacterial community undergoes significant changes with cellulase and xylanase treatments, with a significant increase in Lactobacillus abundance in the C_14, X_30, C_30, X_60, and C_60 treatment groups, while Weissella abundance gradually decreases with longer ensiling times. Two exogenous fibrolytic enzymes also alter the bacterial diversity of ensiled oat, with different bacterial species and abundances observed in different treatment groups. Ensiled oat treated with cellulase and xylanase experiences significant changes in its own bacterial community, particularly in the abundance of Lactobacillus. These changes result in improved fermentation and nutritional quality of oat, but the higher metabolism levels observed after 60 days of ensiling with cellulase treatment may lead to energy loss.

Abstract Background Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly. However, whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear. Sansha Bay is an enclosed bay with ongoing eutrophication, located in the southeast coast of China. We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes. Results Diversity analyses revealed that the bacterial community composition among seasons differed significantly. By contrast, there was little difference in the community composition between the two depths. The temperature was the key environmental factor influencing the community composition. The null model indicated that the relative importance of homogeneous selection decreased in the following order: spring > winter > autumn > summer. Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay. The effects of pure spatial variables on the community assembly were prominent in autumn and winter. Conclusions Our results showed the seasonal influence of eutrophication on bacterial community diversity. The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability. Eutrophication could enhance the importance of homogeneous selection in the assembly processes, but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes. Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay. The bacterial community was the most complex in summer, because the composition differed from other seasons, and the assembly process was the most intricate. These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.

Imbalance in the microbiota has been identified in Crohn's disease (CD). We explored the difference of the microbiota in fecal and intestinal mucosa (including ileocecal junction, terminal ileum and transverse colon) in pediatric patients with active CD, CD patients in remission, nonspecific enteritis (NE) and the healthy children. Seven children had active CD, 5 cases of patients achieve remission (CDR), 19 were NE patients, and 11 were healthy controls (Col). A total of 168 samples were collected. Microbiota compositions were analyzed using 16 ​S rRNA sequencing. The results showed that, in fecal samples, Clostridium_sensu_stricto, Enterobacter and Akkermansia had a higher relative abundance in the CD group than that in CDR, Col and NE groups. Fusobacterium and Streptococcus showed a higher abundance in both CD and CDR than that in Col group. In intestinal mucosa samples, the bacterial communities of the three sampling sites were extremely similar. Escherichia-Shigella was the most abundant mucosal bacteria in the CD group, and the abundance of Bacillus, Ruminococcus_torques_group, Streptococcus, Faecalibacterium and Blautia was lower in the CD group than in other groups. In conclusion, as a very characteristic bacteria, the abundance of Escherichia-Shigella in the intestinal mucosa can be used as a diagnostic criterion for CD patients. Also, the Bacilus and Blautia, which were not as prominent as Escherichia-Shigella could still be used as a diagnostic candidate due to their neatness in CD patients. Mucosal samples may be better than stool samples when assessing the community and diversity of patients' intestinal microbes.

Purpose: As a high-yield by-products of biogas engineering, biogas residue (BR) are limited in the application of soil fertility due to their ecological threat. Therefore, conversing BR into biochar is to be considered. However, whether BR biochar still had ecological risk to soils (especially the widely distributed soils such as Ultisol soil) remains to be probed. Materials and methods: Considering that soil microbial communities and carbon (C) pools play crucial roles in soil ecological environment, the soil bacterial communities, dissolved organic C (DOC) molecular structure, and bulk C mineralization in soils with BR (SBR) and BR biochar (produced at 300 °C, 600 °C, and 800 °C) addition (SBC) were explored in a microcosm incubation experiment using the Ultisol soil (clay loam soil). Soil without biochar addition was set as control (CK). The key technology of Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) was adopted in DOC molecular structure determination. Results and discussion: SBC300 and SBC600 significantly increased Shannon and Simpson indices by 4.3–7.7% and 2.3–2.6% than SBR. The abundance of Chloroflexi, Acidobacteria, Planctomycetes, and Firmicutes phyla were ordered with CK > SBC > SBR. ESI-FT-ICR-MS results showed that the DOC in SBC and SBR had more proteins, carbohydrates, and unsaturated hydrocarbons than in CK, and the highest increases emerged in SBC600. The soil C mineralization ability showed SBR > SBC > CK. The increase of SOC mineralization and the simplification of DOC molecular structure were significantly related to the increase of Proteobacteria and the decrease of Firmicutes. The structural equation modeling showed DOC concentration (SPC = − 0.300), bacterial community richness (SPC = 0.271), and diversity (SPC = − 0.939) were the important abiotic and biotic factors regulating C mineralization. Conclusions: In conclusion, the application of BR biochar had lower ecological risk than direct application of BR in the Ultisol soil. [ABSTRACT FROM AUTHOR]

It is a two-way interaction between algae bloom events and nutrient cycles in aquatic environments. In Meiliang bay of Taihu Lake, phosphorus (P) forms in the water, sediment and pore water, and bacterial community structures in the sediment were investigated in June 2021 (the algae bloom period) and December 2021 (the algae collapse period). The aim of this study is to clarify the periodic variations of P migration and transformation driven by algae bloom and collapse. Results showed that concentrations of total P and total particulate P in the water during the algae bloom period (.13–.25 mg/L) were much higher than those during the algae collapse period (0–.13 mg/L), which was mainly caused by the uptake of phosphate (PO43-) by algae in the surface water. Compared with the algae bloom period, there were higher concentrations of organic P (OP), iron-bound P (FeP) and inorganic P in the sediments during the algae collapse period. The propositions of OP and FeP in total P in the sediments increased from 19% to 17% during the algae bloom period to 27% and 33% during the algae collapse period. These suggest the cumulative trend of OP and FeP in the sediments during the algae collapse period, and FeP might be formed through the processes of OP mineralization and P adsorption by iron oxides/hydroxides in the sediments. Different routes of sediment P regeneration existed over the two periods. During the algae bloom period, the similar vertical variations of labile PO43- and labile Fe2+ in the sediments provided in situ, high-resolution evidence for FeP reductive dissolution driven by FRBs activities. During the algae collapse period, OP mineralization driven by organic P-solubilizing bacteria activities and accelerated by the sulfate reduction process was confirmed by the similar vertical variations of labile PO43- and labile S2- in the sediments. Therefore, treatment approaches and management practices should consider the periodic variations of internal P cycles in aquatic environments during the algae bloom and algae collapse periods to avoid inefficient treatments of lake eutrophication and algae bloom.

Community and composition of dust-borne microbes would affect human health and are regulated by microbial community assembly. The dust in kindergarten is always collected to evaluate the microbial exposure of children, yet the microbial assembly, their interactions, and potential pathogens in kindergarten dust remain unclear. Here, we aim to investigate the microbial community assembly and structures, and potential bacterial pathogens in outdoor dust of kindergartens, and reveal the factors influencing the assembly and composition of microbial community. A total of 118 urban dust samples were collected on the outdoor impervious surfaces of 59 kindergartens from different districts of Xiamen in January and June 2020. We extracted microbial genomic DNA in these dusts and characterized the microbial (i.e., bacteria and fungi) community compositions and diversities using target gene-based (16S rRNA genes for bacterial community and ITS 2 regions for fungal community) high-throughput sequencing. Potential bacterial pathogens were identified and the interactions between microbes were determined through a co-occurrence network analysis. Our results showed the predominance of Actinobacteria and α-Proteobacteria in bacterial communities and Capnodiales in fungal communities. Season altered microbial assembly, composition, and interactions, with both bacterial and fungal communities exhibiting a higher heterogeneity in summer than those in winter. Although stochastic processes predominated in bacterial and fungal community assembly, the season-depended environmental factors (e.g., temperature) and interactions between microbes play important roles in dust microbial community assembly. Potential bacterial pathogens were detected in all urban dust, with significantly higher relative abundance in summer than that in winter. These results indicated that season exerted more profound effects on microbial community composition, assembly, and interactions, and suggested the seasonal changes of potential risk of microbes in urban dust. Our findings provide new insights into microbial community, community assembly, and interactions between microbes in the urban dust, and indicate that taxa containing opportunistic pathogens occur commonly in urban dust.

Raw camel milk is generally contaminated with varied microbiota, including antibiotic–resistant bacteria (ARB), that can act as a potential pathway for the spread of antibiotic resistance genes (ARGs). In this study, high–throughput quantitative PCR and 16S rRNA gene–based Illumine sequencing data were used to establish a comprehensive understanding of the antibiotic resistome and its relationship with the bacterial community in Bactrian camel milk from Xinjiang. A total of 136 ARGs and up to 1.33 × 108 total ARG copies per gram were identified, which predominantly encode resistance to β–lactamas and multidrugs. The ARGs’ profiles were mainly explained by interactions between the bacteria community and physicochemical indicators (77.9%). Network analysis suggested that most ARGs exhibited co–occurrence with Corynebacterium, Leuconostoc and MGEs. Overall, raw camel milk serves as a reservoir for ARGs, which may aggravate the spread of ARGs through vertical and horizontal gene transfer in the food chain.

This study investigated the performance of thermophilic–mesophilic (T-M) and mesophilic–thermophilic (M-T) two-phase sludge anaerobic digestion at different inoculation proportions after a change in digestion temperature. After temperature change, the pH, total ammonia nitrogen (TAN), free ammonia nitrogen (FAN), solubility chemical oxygen demand (SCOD), and total alkalinity (TA) levels of two-phase digesters were between thermophilic control digesters and mesophilic control digesters. However, the volatile fatty acid (VFA) levels of two-phase digesters were higher than those of thermophilic or mesophilic control digesters. The bacteria communities of M-T two-phase digesters were more diverse than those of T-M. After a change in digestion temperature, the bacterial community was dominated by Coprothermobacter. After a change of digestion temperature, the relative abundance (RA) of Methanobacterium, Methanosaeta, and Methanospirillum of M-T two-phase digesters was higher than that of T-M two-phase digesters. In comparison, the RA of Methanosarcina of T-M two-phase digesters was higher than that of M-T two-phase digesters. The ultimate methane yields of thermophilic control digesters were greater than those of mesophilic control digesters. Nevertheless, the ultimate methane yield levels of M-T two-phase digesters were greater than those of T-M two-phase digesters. The ultimate methane yields of all two-phase digesters presented an earlier increase and later decrease trend with the increasing inoculation proportion. Optimal methane production condition was achieved when 15% of sludge (T-M15) was inoculated under mesophilic–thermophilic conditions, which promoted 123.6% (based on mesophilic control) or 27.4% (based on thermophilic control). An optimal inoculation proportion (about 15%) balanced the number and activity of methanogens of high-solid sludge anaerobic digestion.

The gut microbiome is essential for processing complex food compounds and synthesizing nutrients that the host cannot digest or produce, respectively. New model systems are needed to study how the metabolic capacity provided by the gut microbiome impacts the nutritional status of the host, and to explore possibilities for altering host metabolic capacity via the microbiome. Here, we colonized the nematode Caenorhabditis elegans gut with cellulolytic bacteria that enabled C. elegans to utilize cellulose, an otherwise indigestible substrate, as a carbon source. Cellulolytic bacteria as a community component in the worm gut can also support additional bacterial species with specialized roles, which we demonstrate by using Lactobacillus plantarum to protect C. elegans against Salmonella enterica infection. This work shows that engineered microbiome communities can be used to endow host organisms with novel functions, such as the ability to utilize alternate nutrient sources or to better fight pathogenic bacteria. Synopsis: A microbe‐host interaction model is developed by colonizing C. elegans with functional bacteria that allow digesting long‐chain cellulose. Direct benefits include increased host larval yield and protection of other gut species against pathogens.Heterologous bacteria (e.g. Pseudomonas cellulosa) in the gut can help C. elegans to digest cellulose, an otherwise indigestible carbon substrate.Cellulolytic bacteria can also support other bacterial species with specialized roles: Lactobacillus protected the worms against Salmonella infection, and interspecies synergy between P. cellulosa and L. plantarum conferred benefit to the host.Engineered microbiome communities may provide host organisms with novel functions, including the ability to use complex nutrient sources and to fight pathogens.C. elegans colonized with bacteria provides a model system for studying microbiome‐host interactions. [ABSTRACT FROM AUTHOR]

Plants and rhizosphere bacterial microbiota have intimate relationships. As neighbors of the plant root system, rhizosphere microorganisms have a crucial impact on plant growth and health. In this study, we sampled rhizosphere soil of sugarcane in May (seedling), July (tillering), September (elongation) and November (maturity), respectively. We employ 16S rRNA amplicon sequencing to investigate seasonal variations in rhizosphere bacteria community structure and abundance, as well as their association with soil edaphic factors. The results demonstrate that soil pH, total nitrogen (TN) and available nitrogen (AN) decrease substantially with time. Rhizosphere bacteria diversity (Shannon) and the total enriched OTUs are also significantly higher in July relative to other months. Bacteria OTUs and functional composition exhibit a strong and significant correlation with soil temperature (Tem), suggesting that Tem was the potential determinant controlling rhizosphere bacteria diversity, enriched OTUs as well as functional composition. Redundancy analysis (RDA) point toward soil total potassium (TK), pH, TN, Tem and AN as principal determinant altering shifting bacteria community structure. Variation partitioning analysis (VPA) analysis further validate that a substantial proportion of variation (70.79%) detected in the rhizosphere bacteria community structure was attributed to edaphic factors. Mfuzz analysis classified the bacterial genera into four distinct clusters, with cluster two exhibiting a distinct and dramatic increase in July, predominantly occupied by Allocatelliglobosispora. The stochastic forest model found the key characteristic bacterial populations that can distinguish the four key growth periods of sugarcane. It may help us to answer some pending questions about the interaction of rhizosphere microorganisms with plants in the future. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the behavioral shifts of constructed wetland (CW) when the treated water was changed from domestic wastewater to mariculture wastewater. The results showed that the average removal efficiencies of ammonium nitrogen (), total nitrogen and chemical oxygen demand (COD) were 29.54, 46.07 and 57.15% in mariculture wastewater, respectively, which were significantly lower than those in domestic wastewater (71.35, 66.34 and 74.98%, respectively). While there was no significant difference in the removal efficiency of nitrate and phosphate (P > 0.05) between the two systems. Based on the analysis of bacterial community and adsorption properties, the results further indicated that the removal mechanism of between both systems was mainly due to substrate adsorption: the maximum adsorption capacity of on the substrate in mariculture wastewater was 5,432 mg kg−1, whereas that in domestic wastewater was 18,033 mg kg−1. In terms of bacterial communities, the dominant bacteria at the family level were Victivallaceae (18.63%) in domestic wastewater and Porphyromonadaceae (18.37%) in mariculture wastewater, which showed the significant alteration to the bacterial community. In conclusion, this study showed that conventional CW could be used for treating wastewater from land-based marine aquaculture, while the operating conditions needed to be optimized in the process of application. HIGHLIGHTS We addressed changes in the reuse of constructed wetlands for treating mariculture wastewater.; Significant inhibitive effects on , total nitrogen and COD removal occurred during the wastewater transformation.; Substrate adsorption negatively affected removal efficiency in constructed wetland-treatment of mariculture wastewater.;

The microorganisms that inhabit the gastrointestinal tract are responsible for multiple chains of reactions that affect their environment and modify the internal metabolism, their study receives the name of microbiome, which has become more relevant in recent years. In the near future, the challenges related to feeding are anticipated to escalate, encompassing the nutritional needs to sustain an overpopulated world. Therefore, it is expected that a better understanding of the interactions between microorganisms within the digestive tract will allow their modulation in order to provide an improvement in the immune system, feed efficiency or the promotion of nutritional characteristics in production animals, among others. In the present study, the main effects of experimental diets in production animals were described, emphasizing the diversity of the bacterial populations found in response to the diets, ordering them between polygastric and monogastric animals, and then describing the experimental diets used and their effect on the microorganisms. It is hoped that this study will help as a first general approach to the study of the role of the microbiome in production animals under different diets.

Most oat forage has low water-soluble carbohydrates (WSC), which may be the main limited factor for silage fermentation safely, but oat is rich in cellulose and hemicellulose; therefore, we assume that xylanase and cellulase as additives can reduce the content of cellulose and xylan in oat silage, increase the microbial fermentable sugar content, and improve the fermentation quality of the silage. After wilting, oats were treated as follows: (i) distributed water (CK); (ii) silages inoculated with xylanase (X); (iii) silages inoculated with cellulase (C), ensiling for 3 days (early stage of silage) and 60 days (late stage of silage), respectively, after ensiling 60 days for a 5-day aerobic exposure study. The pH, neutral detergent fiber (NDF), and acid detergent fiber (ADF) were significantly reduced by xylanase and cellulase treatment during the late stage of silage, and the concentration of lactic acid, acetic acid, and ammonia nitrogen increased remarkably. The WSC content reached its peak with xylanase treatment during the late stage of silage. The content of crude protein (CP) was not affected by additives but by the silage period; CP and ether extract (EE) significantly increased during the late stage of silage compared to the early stage. After ensiling, the bacterial community showed that xylanase and cellulase treatment increased the relative abundance of lactic acid bacteria. Lactobacillus has a higher relative abundance with cellulase treatment after 60 days of ensiling; this can effectively reduce the pH of silage and ensure long-term, stable storage of silage. Cellulase and xylanase increased bacterial diversity during aerobic exposure and improved the aerobic stability of silage significantly. This study indicated that different additives and silage periods had significant effects on chemical compositions, fermentation quality, and bacterial community; meanwhile, both additives improved the aerobic stability of silage. In summary, when the WSC of oat is low, cellulase and xylanase have good effects as silage additives, and the comprehensive effect of cellulase is more prominent.