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Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quinones, redox-active functional groups in soil organic matter, can act as electron shuttles for microbial anaerobic transformation. Here, we used 13CH4 to trace 13C conversion (13C-CO2 + 13C-SOC) to investigate the influence of an artificial electron shuttle (anthraquinone-2,6-disulfonate, AQDS) on denitrifying anaerobic methane oxidation (DAMO) in paddy soil. The results showed that AQDS could act as the terminal electron acceptor for the anaerobic oxidation of methane (AOM) in the paddy field. Moreover, AQDS significantly enhanced nitrate-dependent AOM rates and the amount of 13C-CH4 assimilation to soil organic carbon (SOC), whereas it was remarkably reduced nitrite-dependent AOM rates and 13C assimilation. Ultimately, AQDS notably increased the total DAMO rates and 13C assimilation to SOC. However, the electron shuttle did not change the percentage of 13C-SOC in total 13C-CH4 conversion. These results suggest that electron shuttles in the natural organic matter might be able to offset methane emission by facilitating AOM coupled with the denitrification process.

Background: Microbial anaerobic metabolism is a key driver of biogeochemical cycles, influencing ecosystem function and health of both natural and engineered environments. However, the temporal dynamics of the intricate interactions between microorganisms and the organic metabolites are still poorly understood. Leveraging metagenomic and metabolomic approaches, we unveiled the principles governing microbial metabolism during a 96-day anaerobic bioreactor experiment. Results: During the turnover and assembly of metabolites, homogeneous selection was predominant, peaking at 84.05% on day 12. Consistent dynamic coordination between microbes and metabolites was observed regarding their composition and assembly processes. Our findings suggested that microbes drove deterministic metabolite turnover, leading to consistent molecular conversions across parallel reactors. Moreover, due to the more favorable thermodynamics of N-containing organic biotransformations, microbes preferentially carried out sequential degradations from N-containing to S-containing compounds. Similarly, the metabolic strategy of C18 lipid-like molecules could switch from synthesis to degradation due to nutrient exhaustion and thermodynamical disadvantage. This indicated that community biotransformation thermodynamics emerged as a key regulator of both catabolic and synthetic metabolisms, shaping metabolic strategy shifts at the community level. Furthermore, the co-occurrence network of microbes-metabolites was structured around microbial metabolic functions centered on methanogenesis, with CH4 as a network hub, connecting with 62.15% of total nodes as 1st and 2nd neighbors. Microbes aggregate molecules with different molecular traits and are modularized depending on their metabolic abilities. They established increasingly positive relationships with high-molecular-weight molecules, facilitating resource acquisition and energy utilization. This metabolic complementarity and substance exchange further underscored the cooperative nature of microbial interactions. Conclusions: All results revealed three key rules governing microbial anaerobic degradation. These rules indicate that microbes adapt to environmental conditions according to their community-level metabolic trade-offs and synergistic metabolic functions, further driving the deterministic dynamics of molecular composition. This research offers valuable insights for enhancing the prediction and regulation of microbial activities and carbon flow in anaerobic environments. 8DQP8VXx1NrDtpo1Z2reYD Video Abstract [ABSTRACT FROM AUTHOR]

Global warming is a potential modifier of biogeochemical cycles, especially in the carbon cycle. This study addresses the decomposition of two distinct types of Myriophyllum aquaticum (Vellozo) Verdcourt detritus (i.e., integral and pre-leached) under aerobic and anaerobic conditions at 21 and 23 ºC. We hypothesized that a 2 ºC increase during the decomposition of M. aquaticum would enhance carbon mineralization, especially under aerobic conditions. Bioassays allowed for experimental temperature and redox conditions during the decomposition of M. aquaticum detritus. Mass loss was measured through time, and mathematical modelling was used to parameterize decomposition and calculate decomposition rates for various carbon fractions. Decomposition was sensitive to 2 ºC temperature increases for integral detritus under both redox conditions. Still, for pre-leached detritus, the temperature effect occurred only under aerobic conditions, indicating a positive impact of temperature on aerobic metabolism performance in carbon decay. Comparing the two types of detritus showed that mineralization under anaerobic conditions was slightly higher (6.2%) than under aerobic conditions. Microbial anaerobic metabolism uses a greater variety of electron acceptors other than only oxygen. Overall, our findings suggest that the increases in litter decomposition rates by temperature warming differ under aerobic and anaerobic conditions. A 2ºC warming in water increases microbial decay of M. aquaticum detritus, indicating stimulation of carbon mineralization. [ABSTRACT FROM AUTHOR]

Expansion of oxygen minimum zones in the world's oceans is likely to enhance the production of anaerobic metabolites by marine microorganisms. Here we show that toluene is present throughout the year in shelf waters of the upwelling ecosystem off Concepción (36° S), Chile, and it is a product of microbial anaerobic metabolism. The intra-annual variability in toluene concentrations is consistent with seasonal variability in the strengths of suboxic equatorial and oxygenated subantarctic water masses. Laboratory incubations of oxygen minimum zone water showed microbial production of toluene in the absence of O2. Toluene concentrations were elevated (up to 96 nM) in deeper O2-depleted waters and followed a seasonal pattern in oceanographic conditions. There is evidence to hypothesize that microbial production of toluene could be a homeostatic biochemical mechanism to thrive in the more acidic oxygen minimum zone waters. On the other hand, evidence indicates that microbial anaerobic degradation of toluene may be a source of NO2− by partial denitrification, as shown for aquifer sediments. Since toluene production was not detected in incubations under aerobic conditions, we hypothesize that oxygen minimum zone waters export toluene to surrounding oxygenated waters. Expansion of hypoxia in the ocean will certainly enhance the production and export of anaerobic metabolites by marine microorganisms. [ABSTRACT FROM AUTHOR]

Abstract Background Microbial anaerobic metabolism is a key driver of biogeochemical cycles, influencing ecosystem function and health of both natural and engineered environments. However, the temporal dynamics of the intricate interactions between microorganisms and the organic metabolites are still poorly understood. Leveraging metagenomic and metabolomic approaches, we unveiled the principles governing microbial metabolism during a 96-day anaerobic bioreactor experiment. Results During the turnover and assembly of metabolites, homogeneous selection was predominant, peaking at 84.05% on day 12. Consistent dynamic coordination between microbes and metabolites was observed regarding their composition and assembly processes. Our findings suggested that microbes drove deterministic metabolite turnover, leading to consistent molecular conversions across parallel reactors. Moreover, due to the more favorable thermodynamics of N-containing organic biotransformations, microbes preferentially carried out sequential degradations from N-containing to S-containing compounds. Similarly, the metabolic strategy of C18 lipid-like molecules could switch from synthesis to degradation due to nutrient exhaustion and thermodynamical disadvantage. This indicated that community biotransformation thermodynamics emerged as a key regulator of both catabolic and synthetic metabolisms, shaping metabolic strategy shifts at the community level. Furthermore, the co-occurrence network of microbes-metabolites was structured around microbial metabolic functions centered on methanogenesis, with CH4 as a network hub, connecting with 62.15% of total nodes as 1st and 2nd neighbors. Microbes aggregate molecules with different molecular traits and are modularized depending on their metabolic abilities. They established increasingly positive relationships with high-molecular-weight molecules, facilitating resource acquisition and energy utilization. This metabolic complementarity and substance exchange further underscored the cooperative nature of microbial interactions. Conclusions All results revealed three key rules governing microbial anaerobic degradation. These rules indicate that microbes adapt to environmental conditions according to their community-level metabolic trade-offs and synergistic metabolic functions, further driving the deterministic dynamics of molecular composition. This research offers valuable insights for enhancing the prediction and regulation of microbial activities and carbon flow in anaerobic environments. Video Abstract

The origin of vitamin D 2 in herbivorous animals was investigated in vivo in sheep and in bovine as well as mouse gastrointestinal tracts. A high concentration of 25-hydroxyvitamin D 2 in blood plasma of sheep both in summer and winter appeared to be incompatible with the undetectable level of vitamin D 2 in the pasture on which the sheep were grazing. Studies with bovine rumen contents from a cow grazing the same pasture as the sheep, demonstrated an increased concentration of vitamin D 2 on anaerobic incubation in a 'Rusitec' artificial rumen, which was further enhanced when cellulose powder was added as a fermentation substrate. The colon contents of mice that were fed from weaning on a vitamin D-free diet were found to contain vitamin D 2. The results of these comparative studies in 3 animal species indicated that vitamin D 2 was being generated by microbial anaerobic metabolism in the gastrointestinal tract. [Display omitted] • Anaerobic gut microorganisms, vitamin D 2 metabolic synthesis in ruminants and in monogastric animals [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Forage culture is a common way to restore degraded grasslands and soil functions, in which the reconstruction of the soil microbial community and its relationship with extracellular enzyme activity (EEAs) can characterize the recovery effects of degraded grasslands. However, the impacts of forage culture on the interaction between soil microbes and EEAs and whether the recovery effect of soil functions depends on the varying degradation statuses remain unclear. Methods: We conducted a plantation of a dominant grass, Leymus chinensis, in the soil collected from severe, moderate, light, and non-degradation statuses in the Songnen grassland in northeastern China. We measured soil microbial diversity and soil EEAs, and predicted microbial functional groups using FUNGuild. Results: The results showed that L. chinensis culture promoted soil bacterial alpha diversity and soil EEAs only in the moderate degradation status, indicating a dramatic dependence of the recovery effects of the grass culture on degradation status of the grassland. After planting L. chinensis for 10weeks, a decreasing trend in the chemoheterotrophy and nitrate-reduction microbial functional groups was found. In contrast, the abundance of the nitrogen (N)-fixing microbial functional group tended to increase. The positive correlation between soil EEAs and the nitratereduction and N-fixing microbial functional groups was enhanced by planting L. chinensis, indicating that grass culture could promote soil N cycle functions. Conclusion: We illuminate that grass culture may promote the restoration of soil functions, especially soil N cycling in degraded grasslands, and the recovery effect may depend on the grassland degradation status. We emphasized that selection of the plant species for restoration of grasslands needs to consider the restoration effects of microbial functional groups and soil functions. [ABSTRACT FROM AUTHOR]

Odor is one of the most intuitive indicators for assessing drinking water quality in waterworks. Removing odors is of great importance to improve the quality of tap water, ensure people's health, and address public perception. The effective identification of odors in drinking water and the exploration of the source of the odor are the prerequisites for eliminating odors. Therefore, this article first discusses the sources and types of odors that are typical in current drinking water, focuses on reviewing the research progress of odor removal technologies in water treatment plants, including adsorption technology, chemical oxidation technology, biodegradation technology and combined technology, and explains the advantages, disadvantages, principles, research progress, practical application scenarios, considerations and application prospects of each odor-removal technology. It is expected to provide a reference for controlling odor pollution in drinking water. [ABSTRACT FROM AUTHOR]

Short-chain fatty acids (SCFAs) were identified and estimated in the gut of three herbivorous fish containing gut endosymbionts, the herring cale Odax cyanomelas (Richardson, 1850) (Family Odacidae), the butterfish O. pullus (Bloch and Schneider, 1801) (Family Odacidae) and the sea carp Crinodus lophodon (Günther, 1859) (Family Aplodactylidae). The highest concentrations of short-chain fatty acids were in the posterior region of the intestine in all species. In O. cyanomelas 85% of the total short-chain fatty acids were found in this region. There was a positive correlation between the distribution of short-chain fatty acids and the microorganisms, suggesting that the short-chain fatty acids were end products of microbial anaerobic metabolism. The major short-chain fatty acid in all three species was acetate, the concentration of which ranged from 20 to 29 mmol·1 in the posterior intestine. Lower concentrations of propionate and butyrate were also found. Additionally, valerate was found in the odacids. The ratio of acetate: propionate:butyrate:valerate in the gut section containing the highest concentration of short-chain fatty acids was 83:8:9:1 in O. cyanomelas, 64:21:14:1 in O. pullus and 74:17:9:0 in C. lophodon. Acetate was present in the blood of O. cyanomelas and C. lophodon at concentrations of 1.74±0.17 and 1.79±0.20 mmol·l, respectively. The presence of the enzyme necessary to activate acetate, acetyl CoA synthetase, in the major tissues of both O. cyanomelas and C. lophodon indicates that these fishes are able to utilise acetate produced in the gut. The highest activity of acetyl CoA synthetase, 3.55±0.51 and 6.48±3.18 nmol·s·g tissue in O. cyanomelas and C. lophodon, respectively, was found in the kidney. Acetyl CoA hydrolase activity was detected in the liver, heart, muscle, gut and kidney of O. cyanomelas and C. lophodon. The highest activity was in the liver of both species, 91.22±9.03 and 57.35±7.15 nmol·s·g tissue in O. cyanomelas and C. lophodon, respectively. The presence of acetyl CoA hydrolase in tissues of O. cyanomelas and C. lophodon raises the possibility that some of the acetate in the blood could arise from hydrolysis of endogenously produced acetyl CoA. The results strongly support the hypothesis that short-chain fatty acids produced by endosymbionts in the posterior intestine are used as a blood fuel either for energy purposes or for lipid synthesis by the host fish. [ABSTRACT FROM AUTHOR]

Lake deoxygenation is of growing concern because it threatens ecosystem services delivery. Complete deoxygenation, anoxia, is projected to prolong and expand in lakes, promoting the production or release of nutrients, greenhouse gases and metals from the water column and sediments. Accumulation of these compounds cannot be easily predicted thus hindering our capacity to forecast the ecological consequences of global changes on aquatic ecosystems. Here, we used monitoring data of four lakes to develop a novel tool, anaerobic duration, to study anaerobic processes in lake waters. Anaerobic duration explained, as a single predictor, 21–60% of the variation for ammonium, phosphorus and a dissolved organic matter fluorophore. Anaerobic duration could be modeled using only two oxygen profiles and lake bathymetry, making it an easily applicable tool to interpret and extrapolate biogeochemical data. This novel tool thus has the potential to transform widely available oxygen profiles into an ecologically meaningful variable. [ABSTRACT FROM AUTHOR]

Abundant unminable coal in deep strata and abandoned mines are also precious sources of clean gas energy, under which biotransformation is a potential path. In recent years, substantial progress has been made in laboratory research on coal degradation to produce methane by microbial metabolism. This paper systematically reviews the research progress of microbial enhancement and microbial stimulation of coal, physicochemical pretreatments of coal, and environmental factors affecting coal biotransformation. The research idea of coal biotransformation should aim at field production increase and gradually clarify the microbial mechanism of coal degradation and the regional distribution and functional composition of microbial communities on the block scale. The research on coal biotransformation helps improve the development level of coalbed methane and the sustainable development of unconventional natural gas resources. [ABSTRACT FROM AUTHOR]

Microbial enhanced oil recovery focuses on the activation, isolation, and screening of aerobic functional bacteria. Air injection is required to activate aerobic microorganisms for use in indigenous microbe oil displacement technology. In practice, however, oil reservoirs are oxygen-free, as the oxygen in the air is rapidly consumed by reducing substances and aerobic microorganisms attached to the water injection well at the front end of the reservoir. In the reservoir, most of the microorganisms metabolize anaerobically, and they are concentrated in the area where the residual oil collects in the rear of the facility. The aim of this study was to investigate the factors such as electron acceptors, activator components, and activator concentrations that influence anaerobic metabolism in indigenous microorganisms. Core flooding tests and field trials were conducted to evaluate the anaerobic microbial activation efficiency. The organic nitrogen source in the activator was crucial to anaerobic bacterial metabolism. Yeast powder was the preferred nitrogen source, and other optimal operating parameters included a C/N ratio of 20:1 and an activator concentration of 3 g·L−1. Under these conditions, the anaerobic emulsification index surpassed 90%. Core flooding tests demonstrated that microbial enhancement may provide up to 13.5% oil recovery. A total of 3471.15 BBLs of oil was recovered by injecting anaerobic activator into the Zhan3-15 well, and emulsified oil droplets were detected in the fluid. The results of this study could provide technical support for the practical anaerobic activation of reservoir microorganisms and the improvement of microbial enhanced oil recovery. [ABSTRACT FROM AUTHOR]

In this study, the effects of redox conditions, nitrogen (NH4+–N and NO3−–N) and phosphate in the overlying water on the release of arsenic (As) in coastal sediments were investigated. The results indicated that the release of As under anaerobic conditions presented a release—dynamic equilibrium pattern. The reduction of arsenate (As(V)) to arsenite (As(III)) under anaerobic conditions was the main factor promoting the release of As. The reductive dissolution of Fe(III) oxides contributed very limited to the release; the release–remove–release pattern was observed under aerobic conditions. Although Fe(III) oxides has strong adsorption capacity for As, sulfide oxidation may be a source of As, which may continuously release As under aerobic conditions. In addition, low concentration (< 6 mg L−1) of nitrogen may stimulate anaerobic metabolism of microorganisms, resulting in reduction and dissolution of As. The low pH of high concentration (> 6 mg L−1) of nitrogen may affect the microbial community and thus decreased the concentration of As. Since the reduction of Fe(III) oxides decreased the adsorption sites, the competitive adsorption of phosphate had no significant effect on the release of As under anaerobic conditions. Totally, this study provides a new understanding of the behavior of As in coastal sediments under variable environments. [ABSTRACT FROM AUTHOR]

Background: Interplay between vaginal microbiome and human papillomavirus (HPV) remains unclear, partly due to heterogeneity of microbiota.Methods: We used data from 546 women enrolled in a cross-sectional study in 5 Brazil. We genotyped vaginal samples for HPV and sequenced V3-V4 region of 16S rRNA gene for vaginal microbiome analysis. We used stepwise logistic regression to construct 2 linear scores to predict high-risk HPV (hrHPV) positivity: one based exclusively on presence of individual bacterial taxa (microbiome-based [MB] score) and the other exclusively on participants' sociodemographic, behavioral, and clinical (SBC) characteristics. MB score combined coefficients of 30 (of 116) species. SBC score retained 6 of 25 candidate variables. We constructed receiver operating characteristic curves for scores as hrHPV correlates and compared areas under the curve (AUC) and 95% confidence intervals (CI).Results: Overall, prevalence of hrHPV was 15.8%, and 26.2% had a Lactobacillus-depleted microbiome. AUCs were 0.8022 (95% CI, .7517-.8527) for MB score and 0.7027 (95% CI, .6419-.7636) for SBC score (P = .0163).Conclusions: The proposed MB score is strongly correlated with hrHPV positivity-exceeding the predictive value of behavioral variables-suggesting its potential as an indicator of infection and possible value for clinical risk stratification. [ABSTRACT FROM AUTHOR]

Background and aims: The pasture legume Trifolium subterraneum ssp. yanninicum exhibits waterlogging tolerance. This study investigates diversity for waterlogging tolerance within ssp. yanninicum. We tested the hypotheses that (1) variation for waterlogging tolerance exists within ssp. yanninicum and (2) is related to phenotypic and growth trait differences, which (3) reflect eco-geographic variables at site of origin. Methods: Twenty-eight diverse ssp. yanninicum ecotypes collected from the Mediterranean region and four cultivars were grown in a controlled environment glasshouse. Seedling traits were measured at 14 and 21 days after sowing. Waterlogged and free-draining (control) treatments were then imposed for 28 days. Relative distance and multivariate plasticity indices were calculated. Results: Under waterlogging, shoot (87–108% of controls) and root (80–116% of controls) relative growth rates (RGRs) differed significantly among ssp. yanninicum. Waterlogging tolerance, as assessed by shoot RGR, had strong positive correlations with root RGR (r = 0.86; P < 0.001), petiole length (r = 0.59; P < 0.001) and leaf size (r = 0.55; P < 0.01) under waterlogging. The proportion of biomass as leaf increased under waterlogging, due to leaf size being maintained (mean 102% of controls), but petiole length decreased (mean 84% of controls). Petiole length was the most plastic trait. Seed size, seedling traits, maturity duration and eco-geographic variables at site of origin were not related to waterlogging tolerance. Conclusions: Wide variation in waterlogging tolerance exists within ssp. yanninicum. Petiole length reduction, an easy-to-measure and non-destructive indicator, could be used as a preliminary selection tool when screening large numbers of ssp. yanninicum for waterlogging tolerance in a breeding program. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the effects of biostimulation and bioagumentation strategies applied to harbor sediments displaying reducing conditions and high concentrations of petroleum hydrocarbons and heavy metals. We compared the microbial efficiency of hydrocarbon removal from sediments maintained for 60days in anoxic conditions and inoculated with acetate, sulfate-reducing bacterial strains and acetate and sulfate-reducing bacteria. All treatments determined a significant increase in the microbial growth and significant decreases of hydrocarbon contents and of redox potential values. The addition of sulfate-reducing bacterial strains to the sediment was the most efficient treatment for the hydrocarbon removal. In all experiments, significant changes of the heavy metals’ phase repartition were observed. The results reported here suggest that the biodegradation of petroleum hydrocarbons in anoxic marine sediments may be enhanced by stimulating microbial anaerobic metabolism, but care should be applied to monitor the potential changes in the mobility and bioavailability of heavy metals induced by bio-treatments. [Copyright &y& Elsevier]

The evolutionary history of sour taste has been little studied. Through a combination of literature review and trait mapping on the vertebrate phylogenetic tree, we consider the origin of sour taste, potential cases of the loss of sour taste, and those factors that might have favoured changes in the valence of sour taste—from aversive to appealing. We reconstruct sour taste as having evolved in ancient fish. By contrast to other tastes, sour taste does not appear to have been lost in any major vertebrate taxa. For most species, sour taste is aversive. Animals, including humans, that enjoy the sour taste triggered by acidic foods are exceptional. We conclude by considering why sour taste evolved, why it might have persisted as vertebrates made the transition to land and what factors might have favoured the preference for sour-tasting, acidic foods, particularly in hominins, such as humans. [ABSTRACT FROM AUTHOR]

Background: Marine animals often exhibit complex symbiotic relationship with gut microbes to attain better use of the available resources. Many animals endemic to deep-sea chemosynthetic ecosystems host chemoautotrophic bacteria endocellularly, and they are thought to rely entirely on these symbionts for energy and nutrition. Numerous investigations have been conducted on the interdependence between these animal hosts and their chemoautotrophic symbionts. The provannid snail Alviniconcha marisindica from the Indian Ocean hydrothermal vent fields hosts a Campylobacterial endosymbiont in its gill. Unlike many other chemosymbiotic animals, the gut of A. marisindica is reduced but remains functional; yet the contribution of gut microbiomes and their interactions with the host remain poorly characterised. Results: Metagenomic and metatranscriptomic analyses showed that the gut microbiome of A. marisindica plays key nutritional and metabolic roles. The composition and relative abundance of gut microbiota of A. marisindica were different from those of snails that do not depend on endosymbiosis. The relative abundance of microbial taxa was similar amongst three individuals of A. marisindica with significant inter-taxa correlations. These correlations suggest the potential for interactions between taxa that may influence community assembly and stability. Functional profiles of the gut microbiome revealed thousands of additional genes that assist in the use of vent-supplied inorganic compounds (autotrophic energy source), digest host-ingested organics (carbon source), and recycle the metabolic waste of the host. In addition, members of five taxonomic classes have the potential to form slime capsules to protect themselves from the host immune system, thereby contributing to homeostasis. Gut microbial ecology and its interplay with the host thus contribute to the nutritional and metabolic demands of A. marisindica. Conclusions: The findings advance the understanding of how deep-sea chemosymbiotic animals use available resources through contributions from gut microbiota. Gut microbiota may be critical in the survival of invertebrate hosts with autotrophic endosymbionts in extreme environments. [ABSTRACT FROM AUTHOR]

Aims: Tolerance to waterlogging and recovery ability was compared among the three subspecies of subterranean clover (Trifolium subterraneum L.) to identify tolerance mechanisms, in order to guide future subclover breeding activities. Methods: Three cultivars each of ssp. yanninicum, subterraneum and brachycalycinum were grown in a controlled environment glasshouse with T. michelianum as a waterlogging-tolerant control. After 28 days of growth two treatments were imposed for 35 days: free-draining (control) and waterlogged. A 21-day recovery period followed. Results: After 35 days, waterlogging reduced shoot dry weight (DW) to 58–27% and root DW to 35–21% of respective controls in each subspecies. Shoot relative growth rate (RGR) of yanninicum was least affected (78–104% of control), compared to subterraneum (51–100%) and brachycalycinum (45–69%). The subterraneum cv. Denmark had a similar response to subspecies yanninicum. Shoot RGR of T. michelianum was 138% of its control. After recovery, all traits (except tap root length) recovered to control values. Up to 21 days, the main traits associated with waterlogging tolerance (shoot and root growth) were high petiole length, less petiole anthocyanin pigmentation and high leaf chlorophyll content, but by 35 days these were a high proportion of leaf biomass, high stomatal conductance and enhanced root porosity. Average root diameter and nodulation rates were unrelated to waterlogging tolerance. Conclusions: Subspecies yanninicum had superior waterlogging tolerance. Priority traits for easily-assessed indicators of waterlogging tolerance are less reduction of leaf size and high stomatal conductance. [ABSTRACT FROM AUTHOR]

Fibroin is a dominant silk protein that possesses ideal properties as a biomaterial for drug delivery. Recently, the development of fibroin nanoparticles (FNPs) for various biomedical applications has been extensively studied. Due to their versatility and chemical modifiability, FNPs can encapsulate different types of therapeutic compounds, including small and big molecules, proteins, enzymes, vaccines, and genetic materials. Moreover, FNPs are able to be administered both parenterally and non-parenterally. This review summaries basic information on the silk and fibroin origin and characteristics, followed by the up-to-date data on the FNPs preparation and characterization methods. In addition, their medical applications as a drug delivery system are in-depth explored based on several administrative routes of parenteral, oral, transdermal, ocular, orthopedic, and respiratory. Finally, the challenges and suggested solutions, as well as the future outlooks of these systems are discussed. [ABSTRACT FROM AUTHOR]

Gut microbiota is important and plays a crucial role in the host health and nutritional metabolism through multiple mechanisms. Short‐chain fatty acids (SCFAs), which are carboxylic acids with aliphatic tails < 6 carbons, are mainly produced by anaerobic microbiota through fermentation of carbohydrates in the intestine. Acetate, propionate and butyrate are the most abundant SCFAs metabolites, important in energy homoeostasis, metabolism and the maintenance of gut health. In this review, we describe and document what is known about the production, absorption, transport and receptors as well as the factors that affect SCFA production in aquatic animals. Some evidence on the roles that SCFAs as feed additives play in improving growth performance, digestibility, survival rate, immune responses, disease resistance and structure and function of the intestinal tract and abundance of commensal microbiota in aquatic animals is summarized. In addition, the immune regulatory mechanism of SCFAs is highlighted. Although the effects of SCFAs in aquatic animals have been explored, further research is needed to profoundly investigate the mechanisms that by which SCFAs induce their effects on host metabolism. [ABSTRACT FROM AUTHOR]

The electron shuttling process has been recognized as an important microbial respiration process. Because the incubation temperature can influence both the reactivity of electron mediators and cell growth, it may also affect the electron-shuttle-mediated extracellular electron transfer (EET) process. Here, the effect of incubation temperature (22–38°C) was investigated in a bioelectrochemical system (BES) using Shewanella oneidensis MR-1 and 50 μM of 9,10-anthraquinone-2-sulfonate (AQS). We found that current generation increased as the temperature was increased from 22 to 34°C and then decreased sharply at 38°C. The biofilm biomass, as indicated by the total protein extracted from the electrode, increased as the temperature increased from 22 to 34°C and then decreased at 38°C, mirroring the current generation results. These results were further confirmed by increasing the temperature slowly, step-by-step, in a single BES with a constant biofilm biomass, suggesting that the EET rates could be substantially influenced by temperature, even with the same biofilm. The effects of temperature on the AQS bioreduction rate, c -type cytochrome (c -Cyts)-bound-cofactor-mediated EET, the AQS mid-point potential, and the AQS diffusion coefficient were studied. From these results, we were able to conclude that temperature influenced the EET rates by changing the c -Cyts-bound-cofactor-mediated EET process and the AQS bioreduction rate, and that the change in biofilm formation was a dominant factor influencing the overall EET rates. These findings should contribute to the fundamental understanding of EET processes. Moreover, optimization of the operating parameters for current generation will be helpful for the practical application of bioelectrochemical techniques. [ABSTRACT FROM AUTHOR]

Glycyl radical enzymes (GREs) are important biological catalysts in both strict and facultative anaerobes, playing key roles both in the human microbiota and in the environment. GREs contain a backbone glycyl radical that is post-translationally installed, enabling radical-based mechanisms. GREs function in several metabolic pathways including mixed acid fermentation, ribonucleotide reduction and the anaerobic breakdown of the nutrient choline and the pollutant toluene. By generating a substrate-based radical species within the active site, GREs enable C-C, C-O and C-N bond breaking and formation steps that are otherwise challenging for nonradical enzymes. Identification of previously unknown family members from genomic data and the determination of structures of well-characterized GREs have expanded the scope of GRE-catalyzed reactions as well as defined key features that enable radical catalysis. Here, we review the structures and mechanisms of characterized GREs, classifying members into five categories. We consider the open questions about each of the five GRE classes and evaluate the tools available to interrogate uncharacterized GREs. [ABSTRACT FROM AUTHOR]

This study investigated the effects of Enterococcus faecalis on digestive enzyme activities and short-chain fatty acid production in fish intestine, resistance against Aeromonas hydrophila and humoral immunity response by 3 experiments on Javanes carp ( Puntius gonionotus). The experiment 1 revealed that diet supplemented with E. faecalis significantly ( P < 0.05) increased protease and lipase activities compared to control fed fish. Moreover, E. faecalis supplementation significantly enhanced the production of propionic and butyric acid in the intestine, while no significant difference ( P > 0.05) in acetic acid production was observed. In the challenge study (experiment 2), fish were injected (intraperitoneal) with 107 A. hydrophila per ml and survival was significantly improved when fish were fed diet supplemented with E. faecalis compared to control fish. In experiment 3, dietary E. faecalis affected immune system response as fish fed the probiont and exposed to 106 A. hydrophila per ml displayed significantly elevated antibody levels compared to control fed fish. Fish fed diet supplemented with E. faecalis but not exposed to the pathogen revealed significantly higher antibody level than control fish ( P < 0.05). Therefore, E. faecalis can be used as a probiotic in Javanese carp farming. [ABSTRACT FROM AUTHOR]

This study aims at investigating decomposition processes in wetlands that are daily or seasonally exposed to intermittent oxic and anoxic conditions. We hypothesized that in wetland ecosystems where anoxia regularly establishes, decomposition rates are not affected by oxygen shortage, especially when nitrates are available. Monitoring and experiments were performed from December 2003 to January 2005 in one of the widest (81 ha) freshwater wetlands in the Po river floodplain (Natural Reserve Paludi del Busatello, Italy). Intact sediment cores were sampled on a seasonal basis. Sediment-water fluxes of oxygen, dissolved inorganic carbon, methane, and inorganic nitrogen were determined under oxic and anoxic conditions. Oxic-anoxic transitions always resulted in enhanced ammonium, dissolved inorganic carbon, and methane effluxes. At high temperatures, the methane release from sediments was inversely related to both nitrate concentrations and uptake. Likely, nitrate can compensate for the oxygen deficiency while maintaining an oxidative metabolism, either supporting microbial decomposition as an electron acceptor or stimulating the oxidation of the byproducts of the anaerobic metabolism, e.g., methane. This is a key point as the number of temperate wetlands with concurrent nitrate pollution and oxygen shortage is increasing throughout the world. [ABSTRACT FROM AUTHOR]

Gut microbiota-produced short chain fatty acids (SCFAs) play an important role in the normal human metabolism and physiology. Although the gradients of SCFAs from the large intestine, where they are largely produced, to the peripheral blood as well as the main routes of SCFA metabolism by different organs are known well for the healthy state, there is a paucity of information regarding how these are affected in disease. In particular, how the inflammation caused by infection or autoinflammatory disease affect the concentration of SCFAs in the peripheral venous blood. In this work, we revealed that diseases caused either by infectious agents (two Salmonella enterica serovars, S. Enteritidis, and S. Typhimurium) or by the exacerbation of an autoinflammatory disease, familial Mediterranean fever (FMF), both result in a significantly elevated systemic concentration of SCFAs. In the case of salmonellosis the concentration of SCFAs in peripheral blood was significantly and consistently higher, from 5- to 20-fold, compared to control. In the case of FMF, however, a significant increase of SCFAs in the peripheral venous blood was detected only in the acute phase of the disease, with a lesser impact in remission. It seems counterintuitive that the dysbiotic conditions, with a reduced number of gut microorganisms, produce such an effect. This phenomenon, however, must be appraised within the context of how the inflammatory diseases affect the normal physiology. We discuss a number of factors that may contribute to the "leak" and persistence of gut-produced SCFAs into the systemic circulation in infectious and autoinflammatory diseases. [ABSTRACT FROM AUTHOR]

Offensive odorant emissions from a food waste (FW) treatment plant that uses hydrothermal hydrolysis and aerobic fermentation technology were studied for 1 month through in situ monitoring and laboratory testing. Results showed that the emission flux (7000 μg kgFW h) of total volatile organic compounds and concentrations of most volatile organic compounds (VOCs) were highest at the discharge outlet of the hydrothermal hydrolysis reactor. Furthermore, VOC composition analysis showed that the concentrations of most hydrocarbons detected during the sorting/crushing process were higher than those in the aerobic fermentation process, but more oxygenated organic compounds and pinenes were released in the aerobic treatment process. The analysis of VOC temporal characteristics via t test indicated that even with various FW loads during the day and night, most VOC concentrations sampled in the storing room were not significantly different. However, great variances among most VOC concentrations were observed during the sorting/crushing process and at the hydrothermal hydrolysis reactor. The annoyance degrees of offensive gases were also determined via analysis of odor indices. The results suggested that sulfocompounds mainly dominated in terms of high odor activate values during the sorting/crushing process, and the fractional content of oxygenated organic compounds increased in the aerobic treatment processes. [ABSTRACT FROM AUTHOR]

Microbial-driven biogeochemical cycles in wetlands impacted by global warming pose a potential downstream eutrophication risk. However, the consequences of ongoing warming on the functional and metabolic potential of sediment microbial communities are largely unknown. We incubated sediment samples under both ambient temperature conditions (control) and simulated warming conditions of 5°C above ambient temperature (warmed) using a novel field microcosm system. In warmed samples, we observed in situ a decreased thickness of the oxidized sediment layer and associated lower sediment redox potential. GeoChip 4.0, a comprehensive functional gene microarray, demonstrated that many functional genes that are involved in oxidation-reduction reactions and in phosphorus (P) degradation were preferentially enriched under warming conditions. The enriched genes included those genes encoding carbon monoxide dehydrogenase, acetyl-CoA carboxylase biotin carboxylase ( ppc), and ribulose-1,5-bisphosphate carboxylase (Rubisco) for carbon fixation; nitrate reductases ( narG) and nitrous oxide reductases ( nosZ) for denitrification; cytochrome c for metal reduction; and exopolyphosphatase ( ppx) for polyphosphate degradation. The redox potential was one of the most significant parameters linked to microbial functional gene structure. These results demonstrate that the enhanced hypoxia and anaerobic metabolic pathways accelerated sediment P mobilization in freshwater wetland subject to warming, raising the potential of water eutrophication. [ABSTRACT FROM AUTHOR]

Purpose: The aims of this study were to isolate an alkaliphilic humus-reducing bacterium, investigate the fastest microbial reduction of humus analog as affected by different cultivation, and examine its ability for iron(III) oxide reduction and organochlorine pollutants (OCPs) degradation. Materials and methods: A strain of pure culture, designated as HN01, was isolated from cassava dreg compost using anaerobic enrichment procedure with glucose as the electron donor and anthraquinone-2,6-disulphonate (AQDS) as the sole terminal electron acceptor. The isolate strain was identified using phenotypic and phylogenetic analysis. Iron(III) oxides and OCPs were chosen as potential electron acceptors. Strict anaerobic techniques and sterile conditions were applied throughout the incubation experiments, purged with O-free N for 15 min. The concentration of reduced AQDS and Fe(II) was then quantified using a UV-vis spectrophotometer. The concentration of OCPs was analyzed by gas chromatography with a micro-electron capture detector. Cell number was determined by direct plate counting on aerobic Luria-Bertani medium agar medium at pH 9. Results and discussion: (1) Strain HN01 was identified as Kocuria rosea, and the AQDS reduction by HN01 was observed in NaCl concentrations below 12 % ( w/ v) (optimum, 10 %) and pH ranges of 6.0-10.0 (optimum, 9.0) with sucrose as electron donor at 30 °C; (2) glucose, sucrose, methanol, ethanol, glycerol, and acetate were the favorable electron donors for AQDS reduction by strain HN01; (3) the strain had the ability of reducing iron(III) oxides in the presence of sucrose at pH 9.0 and its Fe(III)-reducing capacity ranked as goethite (α-FeOOH) > lepidocrocite (γ-FeOOH) > haematite(α-FeO); and (4) the strain could effectively dechlorinate p, p′-DDT (1,1,1-trichloro-2,2- bis(4-chlorophenyl) ethane), and the dechlorination rate reached 71.3 %. Conclusions: This is the first report of a strain of K. rosea capable of reducing AQDS, iron (III) oxides, and p, p′-DDT, which extends the diversity of the alkaliphilic and halotolerant humus/Fe(III)-reducing bacterium associated with dechlorination. The strain may have the potential to be used for bioremediation of an anoxic alkaline wastewater or site contaminated with OCPs. [ABSTRACT FROM AUTHOR]

Gas-phase ?3 oxidation is effective to treat H2S emitted from wastewater treatment processes. The reaction is fast for full-scale applications. In most cases, 67-96% of total H2S removed in 40-s reaction time was achieved within the first 8 s of reaction time. The initial [O>3]/[H2S] ratio of 8 was suffi-cient to reduce H2S from up to 8 ppmv to less than 0.5 ppmv in 40-s reaction time. The reaction stoichiometry ratio of [O3] / [H2S] ranged from 2.0 to 3.7, depending on the initial [O3]/[H2S] ratio. The moisture content, dimethyl sulfide, and dimethyl disulfide in the odorous air influence H2S removal. [ABSTRACT FROM AUTHOR]

Salinity and waterlogging are two major factors affecting crop production around the world and often occur together (e.g., salt brought to the surface by rising water tables). While the physiological and molecular mechanisms of plant responses to each of these environmental constraints are studied in detail, the mechanisms underlying plant tolerance to their combined stress are much less understood. In this study, whole-plant physiological responses to individual/combined salinity and waterlogging stresses were studied using two barley varieties grown in either vermiculite (semi-hydroponics) or sandy loam. Two weeks of combined salinity and waterlogging treatment significantly decreased plant biomass, chlorophyll content, maximal quantum efficiency of PSII and water content (WC) in both varieties, while the percentage of chlorotic and necrotic leaves and leaf sap osmolality increased. The adverse effects of the combined stresses were much stronger in the waterlogging-sensitive variety Naso Nijo. Compared with salinity stress alone, the combined stress resulted in a 2-fold increase in leaf Na+, but a 40% decrease in leaf K+ content. Importantly, the effects of the combined stress were more pronounced in sandy loam compared with vermiculite and correlated with changes in the soil redox potential and accumulation of Mn and Fe in the waterlogged soils. It is concluded that hypoxia alone is not a major factor determining differential plant growth under adverse stress conditions, and that elemental toxicities resulting from changes in soil redox potential have a major impact on genotypic differences in plant physiological and agronomical responses. These results are further discussed in the context of plant breeding for waterlogging stress tolerance. [ABSTRACT FROM AUTHOR]

Aromatic sensitizers and related compounds (SRCs) originating from thermal recording material as impurities in waste paper have been detected in aquatic environments near cities where the paper industry is flourishing. In the present study, the levels of exposure to such SRCs and the stable isotope ratios (δ13C and δ15N) in different fish species ( Konosirus punctatus, Takifugu niphobles, and Tribolodon hakonensis) were analyzed. These fish species were collected from the vicinity of waste paper recycling plants in Japan. Eleven SRCs were identified in fish muscle at total concentration levels (ΣSRCs) of 64 to 818 ng/g wet weight (mean 181 ng/L wet wt). The dominant SRCs in the fish samples were 1,1-di(4-methylphenyl)ethane, 1,2-bis(3-methylphenoxy)ethane, and 1,4-dibenzyloxybenzene. Stable isotope ratios showed that, although three species feed on the same trophic level, K. punctatus and T. niphobles live in waters farther offshore than those in which T. hakonensis live. The contributions of various factors to the accumulation were also assessed. The lipid content ( r2 = 0.512, p < 0.001) was found to be the significant factor that influenced accumulation of SRCs in fish. The results also revealed significant positive correlation between the accumulation patterns and SRC components in water ( r2 = 0.512-0.658, all p values <0.05), but they showed negative correlations between the SRCs in fish and log KOW values. This suggests that the aqueous route is the predominant route for the accumulation of SRCs in fish. This is the first study on the accumulation of aromatic sensitizers in aquatic biota. Environ. Toxicol. Chem. 2012;31:1202-1208. © 2012 SETAC [ABSTRACT FROM AUTHOR]

Over the last ten years, the recently discovered process of direct electron transfer from anaerobically grown microorganisms to an electrode of a fuel cell has been the object of intense study. The microorganisms responsible for such electron transport were termed electrogenic; the devices using them to generate electric current, microbial fuel cells (MFCs). The review discussed the molecular mechanisms of electron transfer to the environment in the case of the two best studied microorganisms, Shewanella oneidensis and Geobacter sulfurreducens. The discovery of bacterial conducting pili (nanowires) used for electron transfer to the electrode and between bacterial cells was sensational. In the real MFCs, which use complex substrates (industrial liquid waste), microbial associations are active, often as biofilms. The progress in MFCs design and the prospects of their practical application are considered. [ABSTRACT FROM AUTHOR]

We analysed and compared the oral microbial flora in four groups with hyposalivation caused by radiation therapy (RT), primary Sjögren's syndrome (pSS), medication or unknown factors (Unknown), or neuroleptic treatment (Neuro). A control group with normal salivary secretion was also included. The subjects included were 54 ± 8 years old and had 25 ± 4 teeth. We analysed their microflora in rinsing samples using a cultivation technique. A marked increase in Lactobacillus spp. and Candida albicans was characteristic of the RT group. In the pSS group, 85% of subjects had high numbers of mutans streptococci despite good oral hygiene, frequent dental visits and fluoride use. The Unknown group had an oral flora similar to that of the controls. In the Neuro group, with a stimulated secretion rate similar to that of the Unknown group, the numbers of aciduric and acidogenic microorganisms were close to those in the pSS group. The results indicate that changes in the oral microflora associated with hyposalivation are related to the reason for the hyposalivation rather than to the magnitude of the decrease in the salivary secretion rate. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy has been used to probe the frozen solution structure of the metal site in Pyrococcus furiosus rubredoxin in the native, iron-containing protein and in zinc- and mercury-substituted proteins. For all samples studied, the spectra have been interpreted in terms of a single shell of coordinated sulfur, with approximately tetrahedral coordination. For the native protein we obtain Fe-S bond-lengths of 2.29 and 2.33 Å for oxidized and reduced proteins, respectively. These values are in excellent agreement with those previously obtained from X-ray crystallography. The metal-substituted rubredoxins possess metal-sulfur bond lengths of 2.34 and 2.54 Å for the zinc- and mercury-substituted proteins, respectively. [ABSTRACT FROM AUTHOR]

The potential of co-digestion mixing thickened secondary sludge (TS) from extended aeration wastewater treatment plant and locally available substrates (whey, grease and septage) has been studied in this work, using three steps. The first step was a batch test to determine the biological methane potential (BMP) of different mixtures of the three co-substrates with TS. The second step was carried out with lab-scale reactors (20 L), simulating anaerobic continuous stirred tank reactors, fed by three mixtures of co-substrates that were determined according to the previous step results. Modeling was applied in the third step, using ADM1 as a mechanistic model to help understand the co-digestion process. According to the BMP step, septage used as a co-substrate has a negative effect on performance, and the addition of 10–30% grease or whey would lead to a gain of around 60–70% in the production of methane. The results from the reactor tests did not validate the positive effects observed with the BMP assay but confirmed good biodegradation efficiency (> 85%). The main purpose of co-digestion in this scenario is to recover energy from waste and effluents that would require even more energy for their treatment. The protein and lipid percentages of particulate biodegradable COD are important variables for digester stability and methane production, as predicted by modeling. The results of simulations with the ADM1 model, adapted to co-digestion, confirmed that this model is a powerful tool to optimize the process of biogas production. [ABSTRACT FROM AUTHOR]

This review focuses on recent advances in the field of enzymatic carboxylation reactions of hydroxyaromatic compounds using HCO3− (as a CO2 source) to produce hydroxybenzoic and other phenolic acids in mild conditions with high selectivity and moderate to excellent yield. Nature offers an extensive portfolio of enzymes catalysing reversible decarboxylation of hydroxyaromatic acids, whose equilibrium can be pushed towards the side of the carboxylated products. Extensive structural and mutagenesis studies have allowed recent advances in the understanding of the reaction mechanism of decarboxylase enzymes, ultimately enabling an improved yield and expansion of the scope of the reaction. The topic is of particular relevance today as the scope of the carboxylation reactions can be extended to include lignin-related compounds in view of developing lignin biorefinery technology. [ABSTRACT FROM AUTHOR]

The polycyclic aromatic hydrocarbon 7-isopropyl-1-methylphenanthrene(retene) induces mixed function oxygenase (MFO) activity of fish. Bile levels of retene and its metabolite(s) were measured in relation to exposure time, exposure concentration, and induction of MFO activity. Synchronous fluorescence spectrometry provided a rapid means of measuring the amount of retene present in the bile of exposed fish, whereas conventional fluorescence spectrometry was used to quantify the amount of retene metabolites. Based on bile analysis, increased retene exposure resulted in an increased uptake of retene and a curvilinear increase in hepatic MFO activity. Retene was present in the bile within 6 h of initial exposure. However, retene metabolite(s) only appeared in the bile after MFO induction had occurred, 12 h after exposure had commenced, suggesting that MFO activity is required for metabolism. Transfer of fish to clean water after 48 h of exposure resulted in a rapid decrease in the presence of retene and its metabolite(s) in the bile, with a calculated half-life of about 14 h. In vitro additions of retene directly to the ethoxyresorufin O-deethylase assay demonstrated that retene is capable of acting as a competitive inhibitor. Thus, retene contamination of postmitochondrial supernatant (S9 fraction) could result in false-negative results in the MFO assay. The MFO activity in extrahepatic tissues (gills, heart, and kidney) was not significantly induced with retene exposure. Thus, the major site ofretene metabolism seems to be in the liver. These results confirm that retene is rapidly taken up, metabolized, and excreted by rainbow trout, and that retene metabolism and excretion are linked to hepatic MFO induction. [ABSTRACT FROM AUTHOR]