The Effects of Preservatives on Antibiotic- and Preservative-Resistant Microbes and Nitrogen/Sulfur Cycle Associated Microbial Communities in Freshwater River Sediments.

The intensive use of benzoic acid (BA), 4-hydroxybenzoic acid (HB), and dehydroacetate (DHA) as additives and preservatives in cosmetics and foods causes emerging environmental pollutions. Anthropogenic releases of BA, HB and DHA are primarily emissions into water and soil. However, few studies investigate the effects of BA, HB and DHA on microbial communities in freshwater river sediments. The aim of this study is to reveal the effects of BA, HB and DHA on microbial communities in freshwater river sediments. Tetracycline-, sulfamethoxazole- and preservative-resistant microbes were increased in the river sediments treated with BA, HB and DHA. The relative abundances of methanogen- and xenobiotic-degradation-associated microbial communities were also increased in the BA-, HB- and DHA-treated sediments. The relative abundance of four nitrogen cycle associated microbial groups (anammox, nitrogen fixation, denitrification, and dissimilatory nitrate reduction) were increased after the eighth week in the BA-, HB- and DHA-treated sediments. For the sulfur cycle, the relative abundance of thiosulfate oxidation associated microbial communities were increased after the eighth week in the BA-, HB- and DHA-treated sediments. Results of this study provide insight into the effects of BA, HB and DHA on antibiotic resistance, nitrogen cycle, sulfur cycle, drug resistance and methane production in freshwater aquatic environments.

Parabens Increase Sulfamethoxazole-, Tetracycline- and Paraben-Resistant Bacteria and Reshape the Nitrogen/Sulfur Cycle-Associated Microbial Communities in Freshwater River Sediments.

Backgrounds Parabens are pollutants of emerging concern in aquatic environments. Extensive studies regarding the occurrences, fates and behavior of parabens in aquatic environments have been reported. However, little is known about the effects of parabens on microbial communities in freshwater river sediments. This study reveals the effects of methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) on antimicrobial-resistant microbiomes, nitrogen/sulfur cycle-associated microbial communities and xenobiotic degrading microbial communities in freshwater river sediments. Methods The river water and sediments collected from the Wai-shuangh-si Stream in Taipei City, Taiwan were used to construct a model system in fish tanks to test the effects of parabens in laboratory. Results Tetracycline-, sulfamethoxazole- and paraben-resistant bacteria increased in all paraben treated river sediments. The order of the overall ability to produce an increment in sulfamethoxazole-, tetracycline- and paraben-resistant bacteria was MP > EP > PP > BP. The proportions of microbial communities associated with xenobiotic degradation also increased in all paraben-treated sediments. In contrast, penicillin-resistant bacteria in both the aerobic and anaerobic culture of paraben-treated sediments decreased drastically at the early stage of the experiments. The proportions of four microbial communities associated with the nitrogen cycle (anammox, nitrogen fixation, denitrification and dissimilatory nitrate reduction) and sulfur cycle (thiosulfate oxidation) largely increased after the 11th week in all paraben-treated sediments. Moreover, methanogens and methanotrophic bacteria increased in all paraben-treated sediments. In contrast, the nitrification, assimilatory sulfate reduction and sulfate-sulfur assimilation associated to microbial communities in the sediments were decreased by the parabens. The results of this study uncover the potential effects and consequences of parabens on microbial communities in a freshwater river environment.

A Novel Phytogenic Formulation, EUBIO-BPSG, as a Promising One Health Approach to Replace Antibiotics and Promote Reproduction Performance in Laying Hens.

Gut microbiota play a key role in health maintenance and disease pathogenesis in animals. Dietary phytochemicals are crucial factors shaping gut bacteria. Here, we investigated the function and mechanism of a phytogenic formulation, EUBIO-BPSG (BP), in laying hens. We found that BP dose-dependently improved health and egg production in 54-week-old hens. Furthermore, BP was correlated with increased fecal Lactobacillus, decreased Escherichia coli and Salmonella enterica, and reduced antibiotic resistance (AR) and antibiotic resistance genes (ARG) in chicken stools. The 16S rDNA data showed that BP increased seven genera of probiotics and reduced 13 genera of pathogens in chicken feces. In vitro co-culture experiments showed that BP at 4 µg/mL and above promoted growth of L. reuteri while large 100- and 200-fold higher doses suppressed growth of E. coli and S. enterica, respectively. Mechanistic studies indicated that L. reuteri and its supernatants antagonized growth of E. coli and S. enterica but not vice-versa. Five short-chain fatty acids and derivatives (SCFA) produced from L. reuteri directly killed both pathogens via membrane destruction. Furthermore, BP inhibited conjugation and recombination of ARG via interference with conjugation machinery and integrase activity in E. coli. Collectively, this work suggests that BP promotes host health and reproductive performance in laying hens through regulation of gut microbiota through increasing probiotics and decreasing pathogens and spreading ARG.

Application of Fungus Enzymes in Spent Mushroom Composts from Edible Mushroom Cultivation for Phthalate Removal.

Spent mushroom composts (SMCs) are waste products of mushroom cultivation. The handling of large amounts of SMCs has become an important environmental issue. Phthalates are plasticizers which are widely distributed in the environment and urban wastewater, and cannot be effectively removed by conventional wastewater treatment methods. In this study, SMCs are tested for their ability to remove phthalates, including benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), and diethyl phthalate (DEP). Batch experiments reveal that BBP, DBP, and DEP can be degraded by the SMC enzyme extracts of four edible mushrooms: Pleurotus eryngii, Pleurotus djamor, Pleurotus ostreatus, and Auricularia polytricha. Potential fungus enzymes associated with BBP, DBP, and DEP degradation in SMCs (i.e., esterases, oxygenases, and oxidases/dehydrogenases) are uncovered by metaproteomic analysis using mass spectrometry. Bioreactor experiments indicate that the direct application of SMCs can remove BBP, DBP, and DEP from wastewater, through adsorption and biodegradation. The results of this study extend the application of white-rot fungi without laccases (e.g., Auricularia sp.) for the removal of organic pollutants which are not degraded by laccases. The application of SMCs for phthalate removal can be developed into a mycoremediation-based green and sustainable technology.

Identification of Novel Biomarkers for Pre-diabetic Diagnosis Using a Combinational Approach.

Reliable protein markers for pre-diabetes in humans are not clinically available. In order to identify novel and reliable protein markers for pre-diabetes in humans, healthy volunteers and patients diagnosed with pre-diabetes and stroke were recruited for blood collection. Blood samples were collected from healthy and pre-diabetic subjects 12 h after fasting. BMI was calculated from body weight and height. Fasting blood glucose (FBG), glycated hemoglobin (HbA1C), triglyceride (TG), total cholesterol, high-density lipoprotein, low-density lipoprotein (LDL), insulin and albumin were assayed by automated clinical laboratory methods. We used a quantitative proteomics approach to identify 1074 proteins from the sera of pre-diabetic and healthy subjects. Among them, 500 proteins were then selected using Mascot analysis scores. Further, 70 out of 500 proteins were selected via volcano plot analysis according to their statistical significance and average relative protein ratio. Eventually, 7 serum proteins were singled out as candidate markers for pre-diabetes due to their diabetic relevance and statistical significance. Immunoblotting data demonstrated that laminin subunit alpha 2 (LAMA2), mixed-lineage leukemia 4 (MLL4), and plexin domain containing 2 (PLXDC2) were expressed in pre-diabetic patients but not healthy volunteers. Receiver operating characteristic curve analysis indicated that the combination of the three proteins has greater diagnostic efficacy than any individual protein. Thus, LAMA2, MLL4 and PLXDC2 are novel and reliable serum protein markers for pre-diabetic diagnosis in humans.

Low compositions of human toll-like receptor 7/8-stimulating RNA motifs in the MERS-CoV, SARS-CoV and SARS-CoV-2 genomes imply a substantial ability to evade human innate immunity.

BACKGROUND: The innate immune system especially Toll-like receptor (TLR) 7/8 and the interferon pathway, constitutes an important first line of defense against single-stranded RNA viruses. However, large-scale, systematic comparisons of the TLR 7/8-stimulating potential of genomic RNAs of single-stranded RNA viruses are rare. In this study, a computational method to evaluate the human TLR 7/8-stimulating ability of single-stranded RNA virus genomes based on their human TLR 7/8-stimulating trimer compositions was used to analyze 1,002 human coronavirus genomes. RESULTS: The human TLR 7/8-stimulating potential of coronavirus genomic (positive strand) RNAs followed the order of NL63-CoV > HKU1-CoV >229E-CoV ≅ OC63-CoV > SARS-CoV-2 > MERS-CoV > SARS-CoV. These results suggest that among these coronaviruses, MERS-CoV, SARS-CoV and SARS-CoV-2 may have a higher ability to evade the human TLR 7/8-mediated innate immune response. Analysis with a logistic regression equation derived from human coronavirus data revealed that most of the 1,762 coronavirus genomic (positive strand) RNAs isolated from bats, camels, cats, civets, dogs and birds exhibited weak human TLR 7/8-stimulating potential equivalent to that of the MERS-CoV, SARS-CoV and SARS-CoV-2 genomic RNAs. CONCLUSIONS: Prediction of the human TLR 7/8-stimulating potential of viral genomic RNAs may be useful for surveillance of emerging coronaviruses from nonhuman mammalian hosts.

Uncovering potential host proteins and pathways that may interact with eukaryotic short linear motifs in viral proteins of MERS, SARS and SARS2 coronaviruses that infect humans.

A coronavirus pandemic caused by a novel coronavirus (SARS-CoV-2) has spread rapidly worldwide since December 2019. Improved understanding and new strategies to cope with novel coronaviruses are urgently needed. Viruses (especially RNA viruses) encode a limited number and size (length of polypeptide chain) of viral proteins and must interact with the host cell components to control (hijack) the host cell machinery. To achieve this goal, the extensive mimicry of SLiMs in host proteins provides an effective strategy. However, little is known regarding SLiMs in coronavirus proteins and their potential targets in host cells. The objective of this study is to uncover SLiMs in coronavirus proteins that are present within host cells. These SLiMs have a high possibility of interacting with host intracellular proteins and hijacking the host cell machinery for virus replication and dissemination. In total, 1,479 SLiM hits were identified in the 16 proteins of 590 coronaviruses infecting humans. Overall, 106 host proteins were identified that may interact with SLiMs in 16 coronavirus proteins. These SLiM-interacting proteins are composed of many intracellular key regulators, such as receptors, transcription factors and kinases, and may have important contributions to virus replication, immune evasion and viral pathogenesis. A total of 209 pathways containing proteins that may interact with SLiMs in coronavirus proteins were identified. This study uncovers potential mechanisms by which coronaviruses hijack the host cell machinery. These results provide potential therapeutic targets for viral infections.

Authentication, phytochemical characterization and anti-bacterial activity of twoArtemisiaspecies.

Artemisia species are aromatic herbs used as food and/or ethnomedicine worldwide; however, the use of these plants is often impeded by misidentification. Here, molecular and chemotaxonomic approaches were combined to assist in the morphology-based authentication of Artemisia species, and Artemisia indica and Artemisia argyi were identified. The plant extracts and compounds obtained from these species, 1,8-cineole, carveol, α-elemene, α-farnesene, methyl linolenate, diisooctyl phthalate inhibited the growth of food-borne harmful bacteria. Mechanistic studies showed that the extract and active compounds of A. indica killed Gram-negative and -positive bacteria via destruction of the bacterial membrane. Finally, in vivo data demonstrated that A. indica protected against bacterial infection in mice as evidenced by survival rate, bacterial load in organs, gut pathology, diarrhea, body weight, food consumption, stool weight, and pathology score. A. indica and its active compounds have potential for use as food supplements for food-borne bacterial diseases and thus improve human health.

Composition of human-specific slow codons and slow di-codons in SARS-CoV and 2019-nCoV are lower than other coronaviruses suggesting a faster protein synthesis rate of SARS-CoV and 2019-nCoV.

Translation of a genetic codon without a cognate tRNA gene is affected by both the cognate tRNA availability and the interaction with non-cognate isoacceptor tRNAs. Moreover, two consecutive slow codons (slow di-codons) lead to a much slower translation rate. Calculating the composition of host specific slow codons and slow di-codons in the viral protein coding sequences can predict the order of viral protein synthesis rates between different virus strains. Comparison of human-specific slow codon and slow di-codon compositions in the genomes of 590 coronaviruses infect humans revealed that the protein synthetic rates of 2019 novel coronavirus (2019-nCoV) and severe acute respiratory syndrome-related coronavirus (SARS-CoV) may be much faster than other coronaviruses infect humans. Analysis of host-specific slow codon and di-codon compositions provides links between viral genomic sequences and capability of virus replication in host cells that may be useful for surveillance of the transmission potential of novel viruses.

Effects of sulfamethoxazole and sulfamethoxazole-degrading bacteria on water quality and microbial communities in milkfish ponds.

Intensive farming practices are typically used for aquaculture. To prevent disease outbreaks, antibiotics are often used to reduce pathogenic bacteria in aquaculture animals. However, the effects of antibiotics on water quality and microbial communities in euryhaline fish culture ponds are largely unknown. The aim of this study was to investigate the interactions between sulfamethoxazole (SMX), water quality and microbial communities in milkfish (Chanos chanos) culture ponds. The results of small-scale milkfish pond experiments indicated that the addition of SMX decreased the abundance of ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and photosynthetic bacteria. Consequently, the levels of ammonia and total phosphorus in the fish pond water increased, causing algal and cyanobacterial blooms to occur. In contrast, the addition of the SMX-degrading bacterial strains A12 and L effectively degraded SMX and reduced the levels of ammonia and total phosphorus in fish pond water. Furthermore, the abundances of AOB, NOB and photosynthetic bacteria were restored, and algal and cyanobacterial blooms were inhibited. This study demonstrate the influences of SMX on water quality and microbial community composition in milkfish culture ponds. Moreover, the use of the bacterial strains A12 and L as dual function (bioaugmentation and water quality maintenance) beneficial bacteria was shown to provide an effective approach for the bioremediation of SMX-contaminated euryhaline milkfish culture ponds.

Anti-coccidial properties and mechanisms of an edible herb, Bidens pilosa, and its active compounds for coccidiosis.

Avian coccidiosis is an economically important disease in the poultry industry. In view of the disadvantages of anti-coccidial drugs in chickens, edible plants and their compounds are re-emerging as an alternative strategy to combat this disease. A previous publication reported that the edible plant B. pilosa showed promise for use against coccidiosis. Here, we first investigated into the anti-coccidial effects of B. pilosa. We found that B. pilosa at 100 ppm or more significantly suppressed E. tenella as evidenced by reduction in mortality rate, oocyst excretion and gut pathological severity in chickens and its minimum prophylactic duration was 3 days. Next, we explored the mode of action of anti-coccidial mechanism of B. pilosa. The E. tenella oocysts were not directly killed by B. pilosa; however, administration of the plant suppressed oocyst sporulation, sporozoite invasion, and schizonts in the life cycle of E. tenella. Besides, B. pilosa boosted T cell-mediated immunity. Finally, we characterized the related anti-coccidial phytochemicals and their mode of action. One of three potent polyynes present in B. pilsoa, Compound 1 (cytopiloyne), acted against coccidiosis in chickens in a similar manner to B. pilosa. These data illustrate the anti-coccidial potency and mechanism of B. pilosa and one of its active compounds, and provide a cornerstone for development of novel herbal remedies for avian coccidiosis.

Anaerobic degradation of sulfamethoxazole by mixed cultures from swine and sewage sludge.

The objective of this study was to evaluate the anaerobic degradation of sulfamethoxazole (SMX) and the associated bacterial community changes in swine and sewage sludges. The degradation rate of SMX was higher in swine sludge than in sewage sludge. The addition of lactate, citrate, and sucrose had significant effects on SMX degradation, and sucrose addition yielded a higher SMX degradation rate than the other additives. At concentrations of 0.1-10 g/l sucrose, the SMX degradation rates increased in the sludge. The bacterial genera from swine sludge with sucrose exhibited the highest SMX degrading efficiency. Seventeen bacterial genera were found to be the major bacterial community members involved in SMX degradation in the sludge.

Characterization of a lytic vibriophage VP06 of Vibrio parahaemolyticus.

Vibrio parahaemolyticus is a human enteropathogenic bacterium and is also pathogenic to shrimp and finfish. In a search for a biocontrol agent for V. parahaemolyticus and other pathogenic Vibrio species, a lytic phage VP06 was isolated from oyster using V. parahaemolyticus as the host. VP06 is a Siphoviridae phage with a polyhedral head and a long tail. The genome sequence of VP06 was 75,893 nucleotides in length and the G + C content was 49%; a total of 101 CDSs were identified in VP06, of which 39 exhibited functional domains/motifs. The genomic sequence of VP06 is similar to those of a lytic Vibrio vulnificus phage SSP002 and a temperate V. parahaemolyticus phage vB_VpaS_MAR10, although VP06 has distinct features in the CDS arrangement and 14 unique CDSs. Phylogenetic analysis revealed that VP06, SSP002 and vB_VpaS_MAR10 belong to a novel genus cluster of Siphoviridae phages. This phage lysed 28.1% of various Vibrio strains, and the efficiency of plating method revealed that VP06 was highly effective in lysing strains of Vibrio alginolyticus, Vibrio azureus, Vibrio harveyi and V. parahaemolyticus. The properties of VP06, including its broad range of hosts and resistance to environmental stresses, indicate that it may be a candidate biocontrol agent.

Anaerobic degradation of sulfamethoxazole in mangrove sediments.

The effects of sucrose and electron acceptors on the anaerobic degradation of sulfamethoxazole (SMX) in mangrove sediments were investigated in this study. Among three sulfonamides, sulfamethoxazole, sulfadimethoxine and sulfamethazine, only SMX could be completely degraded in mangrove sediments. Degradation of SMX was enhanced by the addition of sucrose to the sediments. The degradation rates of SMX were increased in bioreactor experiments with sucrose. The addition of electron acceptors (sodium hydrogen carbonate, sodium sulfate, and sodium nitrate) could further enhance SMX degradation. The order of anaerobic SMX degradation rates under three different conditions was as follows: sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. Methanolobus, Desulfuromonas, and Thauera were found in the highest proportions among methanogens, sulfate-reducing bacteria and denitrifying bacteria, respectively. Achromobacter, Brevundimonas, Delftia, Idiomarina, Pseudomonas, and Rhodopirellula were the major bacterial communities responsible for SMX degradation in the sediment. Overall, 16 bacterial and archaeal genera were identified as the core microbial community facilitating anaerobic SMX degradation for all methanogenic, sulfate-reducing and nitrate-reducing conditions. The results of this study provide feasible methods for the removal of SMX from mangrove sediments.

Removal of emerging contaminants using spent mushroom compost.

Acetaminophen and sulfonamides are emerging contaminants. Conventional wastewater treatment systems fail to degrade these compounds properly. Mycoremediation, is a form of novel bioremediation that uses extracellular enzymes of white-rot fungi to degrade pollutants in the environment. In this study, spent mushroom compost (SMC), which contains fungal extracellular enzymes, was tested for acetaminophen and sulfonamides removal. Among the SMCs of nine mushrooms tested in batch experiments, the SMC of Pleurotus eryngii exhibited the highest removal rate for acetaminophen and sulfonamides. Several fungal extracellular enzymes that might be involved in removal of acetaminophen and sulfonamides were identified by metaproteomic analysis. The bacterial classes, Betaproteobacteria and Alphaproteobacteria, were revealed by metagenomic analysis and may be assisting with acetaminophen and sulfonamide removal, respectively, in the SMC of Pleurotus eryngii. Bioreactor experiments were used to simulate the capability of Pleurotus eryngii SMC for the removal of acetaminophen and sulfonamides from wastewater. The results of this study provide a feasible solution for acetaminophen and sulfonamide removal from wastewater using the SMC of Pleurotus eryngii.

Fungi extracellular enzyme-containing microcapsules enhance degradation of sulfonamide antibiotics in mangrove sediments.

Mangroves represent a special coastal vegetation along the coastlines of tropical and subtropical regions. Sulfonamide antibiotics (SAs) are the most commonly used antibiotics. The application of white-rot fungi extracellular enzyme-containing microcapsules (MC) for aerobic degradation of SAs in mangrove sediments was investigated in this study. Degradation of three SAs, sulfamethoxazole (SMX), sulfadimethoxine (SDM), and sulfamethazine (SMZ), was enhanced by adding MC to the sediments. The order of SA degradation in batch experiments was SMX > SDM > SMZ. Bioreactor experiments revealed that SA removal rates were higher with than without MC. The enhanced SA removal rates with MC persisted with three re-additions of SAs. Thirteen bacteria genera (Achromobacter, Acinetobacter, Alcaligenes, Aquamicrobium, Arthrobacter, Brevundimonas, Flavobacterium, Methylobacterium, Microbacterium, Oligotropha, Paracoccus, Pseudomonas, and Rhodococcus) were identified to be associated with SA degradation in mangrove sediments by combination of next-generation sequencing, bacterial strain isolation, and literature search results. Results of this study suggest that MC could be used for SA removal in mangrove sediments.

Curcumin Induces p53-Null Hepatoma Cell Line Hep3B Apoptosis through the AKT-PTEN-FOXO4 Pathway.

OBJECTIVE: Curcumin (diferuloylmethane) is a yellow-colored polyphenol with antiproliferative and proapoptotic activities to various types of cancer cells. This study explored the mechanism by which curcumin induces p53-null hepatoma cell apoptosis. RESULTS: AKT, FOXO1, and FOXO3 proteins were downregulated after curcumin treatment. Conversely, PTEN was upregulated. Subcellular fractionations revealed that the FOXO4 protein translocated from cytosol into the nucleus after curcumin treatment. Overexpression of FOXO4 increases the sensitivity of Hep3B cells to curcumin. Knockdown of the FOXO4 gene by siRNA inhibits the proapoptotic effects of curcumin on Hep3B cell. CONCLUSIONS: This study revealed the AKT/PTEN/FOXO4 pathway as a potential candidate of target for treatment of p53-null liver cancers.

A comparison of the molecular subtypes of triple-negative breast cancer among non-Asian and Taiwanese women.

BACKGROUND: "Precision medicine" is a concept that by utilizing modern molecular diagnostics, an effective therapy is accurately applied for each cancer patient to improve their survival rates. The treatment of triple-negative breast cancer (TNBC) remains a challenging issue. The aim of this study was to compare the molecular subtypes of triple-negative breast cancer (TNBC) between Taiwanese and Non-Asian women. METHODS: GEO Datasets for non-Asian (12 groups, n = 1450) and Taiwanese (3 groups, n = 465) breast cancer, including 617 TNBC, were acquired, normalized and cluster analyzed. Then, using TNBC cell lines of different subtypes, namely, MDA-MB-468 (basal-like1, BL1), MDA-MB-231 (mesenchymal stem like, MSL), BT-549 (mesenchymal, M), MDA-MB-453 (luminal androgen receptor, LAR), and DU4475 (immunomodulatory, IM), real-time PCR in triplicate for 47 genes signatures were performed to validate the specificity of these subtypes. RESULTS: The results showed that the percentage of TNBC subtypes in non-Asian women, namely, BL1, BL2, IM, M, MSL, and LAR was 13.56, 8.91, 16.80, 20.45, 8.30, and 11.13%, respectively. When data from Taiwanese were normalized and clustered, five TNBC subtypes, namely, BL (8.94%), IM (13.82%), M (22.76%), MSL (30.89%), and LAR (23.58%), were classified. Real-time PCR validated the specificity of these subtypes. Besides, the presence of interaction between IM- and MSL-subtypes suggests the involvement of tumor microenvironment in TNBC subtype classification. CONCLUSION: Our data suggested that there exist different presentations between non-Asian and Taiwanese TNBC subtypes, which provides important information when selection of therapeutic targets or designs for clinical trials for TNBC patients.

Microbial communities associated with anaerobic degradation of polybrominated diphenyl ethers in river sediment.

BACKGROUND/PURPOSE: Polybrominated diphenyl ethers (PBDEs) are extensively used as a class of flame retardants and have become ubiquitous environmental pollutants. We aimed to uncover the changes in microbial community with PBDE anaerobic degradation with and without zero-valent iron in sediment from the Erren River, considered one of the most heavily contaminated rivers in Taiwan. METHODS: PBDE anaerobic degradation in sediment was analyzed by gas chromatography with an electron capture detector. Microbial community composition was analyzed by a pyrosequencing-based metagenomic approach. RESULTS: The anaerobic degradation rate of BDE-209 was higher than BDE-28 in sediment; the addition of zero-valent iron enhanced the degradation rates of both. In total, 19 known bacterial genera (4 major genera: Clostridium, Lysinibacillus, Rummeliibacillus, and Brevundimonas) were considered PBDE degradation-associated bacteria (sequence frequency negatively correlated with PBDE remaining percentage) as were four known archaea genera (Methanobacterium, Methanosarcina, Methanocorpusculum, and Halalkalicoccus; sequence frequency positively correlated with PBDE remaining percentage). CONCLUSION: The composition of bacteria and that of archaea affected the anaerobic degradation of BDE-28 and BDE-209. The addition of zero-valent iron further decreased the archaea content to undetectable levels.

Bacterial communities associated with anaerobic debromination of decabromodiphenyl ether from mangrove sediment.

This study evaluated decabromodiphenyl ether (BDE-209) anaerobic debromination and bacterial community changes in mangrove sediment. BDE-209 debromination rates were enhanced with zerovalent iron compared to without zerovalent iron in the sediment. BDE-209 debromination rates in microcosms constructed with sediments collected in autumn were higher than in microcosms constructed with sediments collected in spring and were higher at the Bali sampling site than the Guandu sampling site. The intermediate products resulting from the reductive debromination of BDE-209 in sediment were nona-BDE (BDE-206, BDE-207), octa-BDEs (BDE-196, BDE-197), hepta-BDEs (BDE-183, BDE-184, BDE-191), hexa-BDEs (BDE-137, BDE-138, BDE-154, BDE-157), penta-BDEs (BDE-85, BDE-99, BDE-100, BDE-126), tetra-BDEs (BDE-47, BDE-49, BDE-66, BDE-77), tri-BDEs (BDE-17, BDE-28), and di-BDEs (BDE-15). Fifty bacterial genera associated with BDE-209 debromination were identified. Overall, 12 of the 50 bacterial genera were reported to be involved in dehalogenation of aromatic compounds. These bacteria have high potential to be BDE-209 debromination bacteria. Different combinations of bacterial community composition exhibit different abilities for BDE-209 anaerobic debromination.