Anaerobe最新文献

{"title":"Development of two recombinant vaccines against Clostridioides difficile infection and immunogenicity in pregnant sows and neonatal piglets","authors":"Carolina P. Ramos ,&nbsp;Williane F. Siqueira ,&nbsp;Laila A. Viana ,&nbsp;João L.R. Cunha ,&nbsp;Ricardo T. Fujiwara ,&nbsp;Victor S. Amarante ,&nbsp;Thayanne G.V. Souza ,&nbsp;Rodrigo O.S. Silva","doi":"10.1016/j.anaerobe.2024.102896","DOIUrl":"10.1016/j.anaerobe.2024.102896","url":null,"abstract":"<div><h3>Introduction</h3><p><em>Clostridioides difficile</em> is the main cause of antibiotic-associated diarrhea in humans and is a major enteropathogen in several animal species. In newborn piglets, colonic lesions caused by <em>C. difficile</em> A and B toxins (TcdA and TcdB, respectively) cause diarrhea and significant production losses.</p></div><div><h3>Objective</h3><p>The present study aimed to develop two recombinant vaccines from immunogenic C-terminal fragments of TcdA and TcdB and evaluate the immune response in rabbits and in breeding sows. Two vaccines were produced: bivalent (rAB), consisting of recombinant fragments of TcdA and TcdB, and chimeric (rQAB), corresponding to the synthesis of the same fragments in a single protein. Groups of rabbits were inoculated with 10 or 50 μg of proteins adjuvanted with aluminum or 0.85 % sterile saline in a final volume of 1 mL/dose. <em>Anti</em>-TcdA and <em>anti</em>-TcdB IgG antibodies were detected in rabbits and sows immunized with both rAB and rQAB vaccines by ELISA. The vaccinated sows were inoculated intramuscularly with 20 μg/dose using a prime-boost approach.</p></div><div><h3>Results</h3><p>Different antibody titers (p ≤ 0.05) were observed among the vaccinated groups of sows (rAB and rQAB) and control. Additionally, newborn piglets from vaccinated sows were also positive for <em>anti</em>-TcdA and <em>anti</em>-TcdB IgGs, in contrast to control piglets (p ≤ 0.05). Immunization of sows with the rQAB vaccine conferred higher <em>anti</em>-TcdA and <em>anti</em>-TcdB responses in piglets, suggesting the superiority of this compound over rAB.</p></div><div><h3>Conclusion</h3><p>The synthesized recombinant proteins were capable of inducing antibody titers against <em>C. difficile</em> toxins A and B in sows, and were passively transferred to piglets through colostrum.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"89 ","pages":"Article 102896"},"PeriodicalIF":2.5,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141911502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The growth-stimulating factor of Treponema phagedenis from bovine digital dermatitis lesions","authors":"Rathanon Khemgaew ,&nbsp;Kaoru Hori ,&nbsp;Satomi Sasaki ,&nbsp;Naoaki Misawa ,&nbsp;Takako Taniguchi","doi":"10.1016/j.anaerobe.2024.102882","DOIUrl":"10.1016/j.anaerobe.2024.102882","url":null,"abstract":"<div><p>Bovine digital dermatitis (BDD) is an infectious skin disease of the hoof characterized by painful ulcerations that cause lameness in dairy cattle. Cell-free supernatants (CFS) of <em>Falsiporphyromonas endometrii</em> predominantly isolated from BDD lesions had the highest growth-stimulating effect on <em>Treponema phagedenis</em> among BDD-associated bacteria. Butyric acid was detected at a concentration of 45.4 mM in CFS of <em>F. endometrii</em>, and the growth of <em>T. phagedenis</em> was significantly promoted by butyric acid supplementation.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"88 ","pages":"Article 102882"},"PeriodicalIF":2.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141726804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of linear B cell epitopes on the leukotoxin protein of Fusobacterium necrophorum","authors":"Jiawei Xiao ,&nbsp;Siwen Yu ,&nbsp;Kai Jiang ,&nbsp;Xianjing He ,&nbsp;Lan Bi ,&nbsp;Pengyu Zhao ,&nbsp;Tianshuo Wang ,&nbsp;Ning Yang ,&nbsp;Donghua Guo","doi":"10.1016/j.anaerobe.2024.102884","DOIUrl":"10.1016/j.anaerobe.2024.102884","url":null,"abstract":"<div><h3>Objective</h3><div><em>Fusobacterium necrophorum</em> can casuse Lemierre's syndrome in humans and a range of illnesses<em>,</em> including foot rot and liver abscesses, in animals. The main virulence factor released by <em>F. necrophorum</em> is leukotoxin, which has been shown to have a strong correlation with the severity of the disease. Leukotoxin is commonly employed as the key antigen in the formulation of subunit vaccines. Therefore, identification of the B-cell epitope of <em>F. necrophorum</em> leukotoxin is necessary.</div></div><div><h3>Methods</h3><div>In this research, we utilized lymphocyte hybridoma technology to develop a monoclonal antibody (mAb), 3D7, targeting the <em>F. necrophorum</em> leukotoxin protein. Identification of B-cell epitopes recognized by 3D7 mAb was achieved through Western blot, ELISA and dot blots using leukotoxin-truncated recombinant proteins and peptides, and through SWISS-MODEL homology modeling and PyMOL visualization.</div></div><div><h3>Results</h3><div>The 3D7 mAb was identified as belonging to the IgG1 subclass with a κ-chain light chain. It demonstrated reactivity with the natural leukotoxin. The results showed that the 3D7 mAb recognizes a B-cell epitope of the <em>F. necrophorum</em> leukotoxin protein, I²¹⁶⁸SSFGVGV²¹⁷⁵ (EP-3D7). Sequence comparison analysis showed that EP-3D7 was highly conserved in <em>F. necrophorum</em> strains, but less conserved in other bacteria, indicating the specificity of EP-3D7. EP-3D7 is present on the surface of leukotoxin proteins in a <em>β</em>-folded manner.</div></div><div><h3>Conclusions</h3><div>In summary, these results establish EP-3D7 as a conserved antigenic epitope of <em>F. necrophorum</em> leukotoxin. It could be valuable in the development of vaccines and diagnostic reagents for <em>F. necrophorum</em> epitopes.</div></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"90 ","pages":"Article 102884"},"PeriodicalIF":2.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141765001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An outbreak of botulism on a pig farm due to the newly described Clostridium botulinum type C","authors":"Caroline Le Maréchal ,&nbsp;Martine Denis ,&nbsp;Louis Vanlemmens ,&nbsp;Léa Jambou ,&nbsp;Gauthier Delvallez ,&nbsp;Typhaine Poezevara ,&nbsp;Mouna Abed-Zahar ,&nbsp;Laure Diancourt ,&nbsp;Marie-Agnès Baudouard ,&nbsp;Eric Eveno ,&nbsp;Marie-Hélène Bayon-Auboyer ,&nbsp;Mustapha Fellag ,&nbsp;Sandra Rouxel ,&nbsp;Nadia Amenna ,&nbsp;Christelle Mazuet ,&nbsp;Jean-Marc Guéguen ,&nbsp;Nicolas Rose","doi":"10.1016/j.anaerobe.2024.102885","DOIUrl":"10.1016/j.anaerobe.2024.102885","url":null,"abstract":"<div><p>This study reports a botulism outbreak on a pig farm. <em>Clostridium botulinum</em> type C was detected using PCR. The gene encoding the toxin corresponds to a novel type C neurotoxin recently described in a human botulism outbreak, raising the question of its prevalence in pigs and the related risks to humans.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"89 ","pages":"Article 102885"},"PeriodicalIF":2.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141765000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Succinate-mediated symbiosis between Dialister hominis and an uncharacterized Segatella-like pectinophile","authors":"Tomoki Makiura ,&nbsp;Minenosuke Matsutani ,&nbsp;Hou-Chia Tseng ,&nbsp;Naoshi Fujimoto ,&nbsp;Akihiro Ohnishi","doi":"10.1016/j.anaerobe.2024.102883","DOIUrl":"10.1016/j.anaerobe.2024.102883","url":null,"abstract":"<div><h3>Objectives</h3><p>Syntrophy has been documented between pectinophiles and methanol-utilizing bacteria, along with instances of cross-feeding between pectinophiles and methanogens. However, studies on the ecology of pectinophiles in anaerobic digestion (AD) are lacking. Therefore, in this study, we aimed to elucidate the ecology of pectinophiles by isolating novel pectinophile forms and conducting a comprehensive analysis of their physiology and ecology.</p></div><div><h3>Methods</h3><p>Complex microbial communities from AD systems were enriched in a pectin-containing medium; subsequently, specific strains were isolated using a pectinophile isolation method. The carbon source assimilation and growth ability of the isolates, along with their symbiotic relationships, were evaluated using batch tests.</p></div><div><h3>Results</h3><p>Strain LPYR103-Pre exhibited 16S rRNA gene sequence similarity and average nucleotide identity values of 94.3 % and 77.9 %, respectively, compared to its closest related species, <em>Segatella cerevisiae</em>. Strain LPYR103-Pre demonstrated attenuated growth in the presence of eight common sugars but exhibited remarkably high growth in the presence of pectin, <span>d</span>-galacturonate, and <span>d</span>-glucuronate, with succinate being identified as a primary metabolite. Accumulation of succinate inhibited the growth of strain LPYR103-Pre. However, this growth impediment was alleviated by <em>Dialister hominis</em> LPYG114-Dih, whose growth required succinate.</p></div><div><h3>Conclusions</h3><p>Our results elucidate the specific carbon source requirements of the <em>Segatella</em>-like strain LPYR103-Pre and succinate-mediated symbiosis involving <em>D. hominis</em>. These findings provide new insights into the degradation of pectin and its degradation products during AD, contributing to the identification of unknown pectinophiles.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"89 ","pages":"Article 102883"},"PeriodicalIF":2.5,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1075996424000660/pdfft?md5=a0cde5f756ad22fe4c115ea4a314dec0&pid=1-s2.0-S1075996424000660-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Association between Bacteroides fragilis and Fusobacterium nucleatum infection and colorectal cancer in Vietnamese patients","authors":"Truong Nguyen Duy ,&nbsp;Hoang Le Huy ,&nbsp;Quyen Đao Thanh ,&nbsp;Hoai Ngo Thi ,&nbsp;Hanh Ngo Thi Minh ,&nbsp;Manh Nguyen Dang ,&nbsp;Song Le Huu ,&nbsp;Trung Ngo Tat","doi":"10.1016/j.anaerobe.2024.102880","DOIUrl":"10.1016/j.anaerobe.2024.102880","url":null,"abstract":"<div><h3>Background</h3><p>Colorectal cancer (CRC) is a significant global health concern, and understanding the role of specific bacterial infections in its development and progression is of increasing interest. This cross-sectional study investigated the associations between <em>Bacteroides fragilis</em> (<em>B. fragilis</em>) and <em>Fusobacterium nucleatum</em> (<em>F. nucleatum</em>) infections and Vietnamese CRC patients.</p></div><div><h3>Methods</h3><p>192 patients with either polyps or CRC at varying stages were recruited from May 2017 to December 2020. Real-time PCR assessed infection rates and bacterial loads in CRC tissues.</p></div><div><h3>Results</h3><p><em>B. fragilis</em> infection was notably higher in CRC tissues (51.6 %) than polyps (9.4 %), with a fivefold higher relative load. Positive associations were found in stages II and III, indicating a fivefold increase in CRC progression risk. <em>F. nucleatum</em> infection rates were significantly higher in CRC tissues (55.2 %) than in polyps (10.5 %). In stage II, the infection rate exceeded that in adjacent tissues. The relative load of <em>F. nucleatum</em> was higher in stage III than in stages I and II. Positive <em>F. nucleatum</em> patients had a 3.2 times higher risk of CRC progression.</p></div><div><h3>Conclusion</h3><p>These findings suggest associations between loading of <em>F. nucleatum</em> or/and <em>B. fragilis</em> with the advanced stages of CRC.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"88 ","pages":"Article 102880"},"PeriodicalIF":2.5,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141465781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Description of Faecalibacterium wellingii sp. nov. and two Faecalibacterium taiwanense strains, aiding to the reclassification of Faecalibacterium species","authors":"","doi":"10.1016/j.anaerobe.2024.102881","DOIUrl":"10.1016/j.anaerobe.2024.102881","url":null,"abstract":"<div><h3>Objectives</h3><p>The genus <em>Faecalibacterium</em> is one of the most important butyrate producers in the human intestinal tract and has been widely linked to health. Recently, several different species have been described, but still more phylogroups have been identified, suggesting that additional species may exist. Four strains HTF-F^T, HTF-128, HTF-75H and HTF-76H, representing two different phylogenetic clusters, are evaluated in this study.</p></div><div><h3>Methods</h3><p>Phylogenomic analysis was performed using whole-genome sequences and 16S rRNA gene sequences. Chemotaxonomic analysis was done based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Physiological and phenotypical characteristics of these strains were also determined. All characteristics of these strains were compared with other validly published species within the genus <em>Faecalibacterium</em>.</p></div><div><h3>Results</h3><p>On a genomic level, the strains HTF-F^T and HTF-128 shared an average nucleotide identity (ANI) of &lt;95.0 % and digital DNA-DNA hybridization (dDDH) of &lt;70.0 with other <em>Faecalibacterium</em> species, while between HTF-F^T and HTF-128 the ANI-value was 97.18 % and the dDDH was 76.8 %. HTF-75H and HTF-76H had an ANI and dDDH value of 100 % (99.96 %) and 100 % (99.99 %) respectively. Both HTF-75H and HTF-76H were closely related to <em>Faecalibacterium taiwanense</em> HLW78^T. 16S rRNA gene and chemotaxonomic analysis were in accordance with the genomic data, confirming that HTF-F^T and HTF-128 represent a novel <em>Faecalibacterium</em> species and HTF-75H and HTF-76H belong to <em>F. taiwanense</em>.</p></div><div><h3>Conclusions</h3><p><em>Faecalibacterium</em> strains HTF-F^T (=DSM 117771^T = NCIMB 15531^T) and HTF-128 represent a novel species. The name <em>Faecalibacterium wellingii</em> with HTF-F^T as type strain is proposed. Two novel isolates HTF-75H (=DSM 17770 = NCIMB 15530) and HTF-76H are described in this study and belong to the recently described <em>Faecalibacterium taiwanense.</em></p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"89 ","pages":"Article 102881"},"PeriodicalIF":2.5,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141454794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incidence of public health surveillance-reported Clostridioides difficile infections in thirteen countries worldwide: A narrative review","authors":"Frederick J. Angulo ,&nbsp;Melissa Furtado ,&nbsp;Elisa Gonzalez ,&nbsp;Pingping Zhang ,&nbsp;Patrick H. Kelly ,&nbsp;Jennifer C. Moïsi","doi":"10.1016/j.anaerobe.2024.102878","DOIUrl":"10.1016/j.anaerobe.2024.102878","url":null,"abstract":"<div><p><em>Clostridioides difficile</em> infection (CDI) is an important cause of morbidity and mortality worldwide. Data from public health surveillance systems are important for estimating country-level CDI burden. CDI surveillance can be population-based or hospital-based. Population-based surveillance results in overall estimates of CDI incidence (cases per 100,000 population-per-year), and hospital-based surveillance results in estimates of hospital-based CDI incidence (cases per 10,000 patient-days) or CDI admission rates (cases per 1,000 admissions). We sought to better understand temporal trends in CDI incidence reported in publicly available surveillance data worldwide and describe varying surveillance methods. We identified 13 countries in Europe, North America, and Oceania with publicly available population-based and/or hospital-based CDI surveillance data in online reports and/or dashboards. Additional countries in Europe, in particular, also conduct hospital-based CDI surveillance. Inconsistent CDI case definitions and surveillance approaches between countries limit the interpretability of multi-country comparisons. Nonetheless, publicly available CDI surveillance data enabled us to compare CDI incidence among countries with population-based and/or hospital-based surveillance systems and to describe trends in CDI incidence within countries over time. The highest CDI incidence is in the United States. While there have been recent declines in CDI incidence in all countries, the CDI burden remains high, and the need persists for CDI prevention strategies in communities and healthcare settings.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"88 ","pages":"Article 102878"},"PeriodicalIF":2.5,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1075996424000611/pdfft?md5=91dab2b840e4c788cd7faaba946d5115&pid=1-s2.0-S1075996424000611-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141442065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacteremia caused by Veillonella parvula: Two case reports and a review of the literature","authors":"Fernando Cobo,&nbsp;María Aguilera-Franco,&nbsp;Virginia Pérez-Carrasco,&nbsp;José A. García-Salcedo,&nbsp;José María Navarro-Marí","doi":"10.1016/j.anaerobe.2024.102879","DOIUrl":"10.1016/j.anaerobe.2024.102879","url":null,"abstract":"<div><p><em>Veillonella parvula</em> is a non-motile Gram-negative coccus that forms part of the normal microbiota in several body sites and which has been rarely isolated as cause of infections in human population, particularly in bacteremias. Here we give the overview of characteristics of genus <em>Veillonella</em> and the summary of its role in infections, particularly in bacteremia. We additionally report two patients with bacteremia due to <em>V. parvula</em>. Two sets of blood cultures of each patient yielded a pure culture of an anaerobic microorganism identified as <em>V. parvula</em> by MALDI-TOF MS, and confirmed by 16S rRNA gene sequencing. The two patients were male and one of them had risk factors for anaerobic bacteremia. The isolates were susceptible to most antibiotics and the outcome was successful in both patients. Bacteremia due to <em>V. parvula</em> is still rare. MALDI-TOF MS appear to be an excellent tool for the correct identification of these species.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"88 ","pages":"Article 102879"},"PeriodicalIF":2.5,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141436557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methylotrophic methanogenesis induced by ammonia nitrogen in an anaerobic digestion system","authors":"Liov Karel Beraud-Martínez ,&nbsp;Miguel Betancourt-Lozano ,&nbsp;Bruno Gómez-Gil ,&nbsp;Ali Asaff-Torres ,&nbsp;Oscar Armando Monroy-Hermosillo ,&nbsp;Miguel Ángel Franco-Nava","doi":"10.1016/j.anaerobe.2024.102877","DOIUrl":"10.1016/j.anaerobe.2024.102877","url":null,"abstract":"<div><h3>Objectives</h3><p>This lab-scale study aimed to investigate the effect of total ammonia nitrogen (TAN) stress on the methanogenic activity and the taxonomic and functional profiles of the microbial community of anaerobic sludge (AS) from a full-scale bioreactor.</p></div><div><h3>Methods</h3><p>The AS was subjected to a stepwise increase in TAN every 14 days at concentrations of 1, 2, 2.5, 3, 3.5, and 4 g TAN/L (Acclimated-AS or AAS). This acclimation stage was followed by an ammonia stress stage (4 g/L). A blank-AS (BAS) was maintained without TAN during the acclimation stage. In the second stress stage (ST), the BAS was divided into two new treatments: a control (BAS') and one that received a shock load of TAN of 4 g/L (SBAS'). Methane production was measured, and a metagenomic analysis was conducted to describe the microbial community.</p></div><div><h3>Results</h3><p>A decrease in the relative abundance of <em>Methanothrix soehngenii</em> of 16 % was related to a decrease of 23 % in the methanogenic capacity of AAS when comparing with the final stage of BAS. However, recovery was observed at 3.5 g TAN/L, and a shift to methylotrophic metabolism occurred, indicated by a 4-fold increase in abundance of <em>Methanosarcina mazei</em>. The functional analysis of sludge metagenomes indicated that no statistical differences (p &gt; 0.05, RM ANOVA) were found in the relative abundance of methanogenic genes that initiate acetoclastic and hydrogenotrophic pathways (acetyl-CoA synthetase, <em>ACSS</em>; acetate kinase, <em>ackA</em>; phosphate acetyltransferase, <em>pta</em>; and formylmethanofuran dehydrogenase subunit A, <em>fwdA</em>) into the BAS and AAS during the acclimation phase. The same was observed between groups of genes associated with methanogenesis from methylated compounds. In contrast, statistical differences (p &lt; 0.05, one-way ANOVA) in the relative abundance of these genes were recorded during ST. The functional profiles of the genes involved in acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways were brought to light for acclimatation and stress experimental stages.</p></div><div><h3>Conclusions</h3><p>TAN inhibited methanogenic activity and acetoclastic metabolism. The gradual acclimatization to TAN leads to metabolic and taxonomic changes that allow for the subsequent recovery of methanogenic functionality. The study highlights the importance of adequate management of anaerobic bioprocesses with high nitrogen loads to maintain the methanogenic functionality of the microbial community.</p></div>","PeriodicalId":8050,"journal":{"name":"Anaerobe","volume":"88 ","pages":"Article 102877"},"PeriodicalIF":2.5,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141309509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}