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Regulatory mechanisms of CH4 : air volume ratios on metabolic flux partitioning in methane-oxidizing bacteria and their impact on single cell protein biosynthetic efficiency. CH4:空气体积比对甲烷氧化菌代谢通量分配的调节机制及其对单细胞蛋白质生物合成效率的影响
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2026-01-01 DOI: 10.3389/fmicb.2026.1646291
Jianxiong Zhang, Jiao He, Jiaying Xin, Tianyu Cui, Chungu Xia

Introduction: C1 gas bioconversion for single-cell protein (SCP) production offers dual environmental benefits by mitigating greenhouse gases and generating protein resources. This study systematically determined optimal methane-to-air ratios (CH4:air, v/v) for enhancing methane-oxidizing bacteria (MOB) growth and SCP yield under three distinct nitrogen assimilation modes: nitrate-driven pMMO expression, ammonium-driven sMMO expression, and nitrogen-fixing sMMO expression.

Methods: Experiments were conducted under three nitrogen assimilation regimes: nitrate-fed pMMO expression, ammonium-fed sMMO expression, and nitrogen-fixing sMMO expression systems. By adjusting the volumetric ratio of methane to air, the effects on bacterial growth, biomass accumulation, specific growth rate, and key enzymatic activities were evaluated. Measured parameters included OD600, cell dry weight, specific growth rate (μmax), and nitrogenase activity in the nitrogen-fixing system. Data from repeated measurements were subjected to statistical analysis to clarify the regulatory role of gas ratios on metabolic pathways.

Results: In the nitrate-fed pMMO expression system, a CH4:air ratio of 1:3 yielded optimal growth, with an OD600 of 1.11, cell dry weight of 0.44 ± 0.023 g/L, and μmax of 0.022 h-1. Similarly, the ammonium-fed sMMO expression system achieved best performance at the same ratio (OD600 1.19, biomass 0.56 ± 0.014 g/L, μmax 0.025 h-1). In contrast, the nitrogen-fixing sMMO expression system performed better at a lower oxygen ratio (CH4:air = 1:2), reaching an OD600 of 0.62, biomass of 0.28 ±0.008 g/L, nitrogenase activity of 1.09 nmol/(min mg protein), and μmax of 0.016 h-1).

Discussion: The results reveal oxygen's critical dual role: higher O2 levels enhance methane oxidation by activating the copper-dependent catalytic site of pMMO but simultaneously and irreversibly damage the oxygen-sensitive nitrogenase ssential for N2 fixation, suppressing its activity. Conversely, lower O2 protects nitrogenase but limits pMMO efficiency. This creates a fundamental metabolic trade-off where the optimal CH4/O2 ratio balances these opposing effects, strategically partitioning cellular energy either toward efficient methane assimilation (favored by higher O2) or toward the ATP-intensive process of nitrogen fixation (requiring lower O2). These identified gas-ratio thresholds provide actionable parameters for designing scaled SCP bioproduction systems, enabling effective coupling of industrial methane mitigation with sustainable protein synthesis through gas-phase engineering.

介绍:C1气体生物转化用于单细胞蛋白(SCP)生产,通过减少温室气体和产生蛋白质资源,具有双重环境效益。本研究在三种不同的氮同化模式下,系统地确定了促进甲烷氧化菌(MOB)生长和SCP产量的最佳甲烷空气比(CH4:空气,v/v):硝酸盐驱动的pMMO表达、氨驱动的sMMO表达和固氮sMMO表达。方法:在三种氮素同化系统下进行实验:硝酸盐饲喂pMMO表达、氨饲喂sMMO表达和固氮sMMO表达。通过调节甲烷与空气的体积比,评估了甲烷对细菌生长、生物量积累、特定生长速率和关键酶活性的影响。测定的参数包括:OD600、细胞干重、特定生长率(μmax)、固氮体系中固氮酶活性。对重复测量的数据进行统计分析,以阐明气体比对代谢途径的调节作用。结果:在硝酸盐饲喂的pMMO表达体系中,CH4:空气比为1:3时生长最佳,OD600为1.11,细胞干重为0.44±0.023 g/L, μmax为0.022 h-1。同样,在相同比例下(OD600为1.19,生物量为0.56±0.014 g/L, μmax为0.025 h-1),氨补sMMO表达体系表现最佳。在低氧比(CH4:空气= 1:2)条件下,固氮sMMO表达体系表现较好,OD600为0.62,生物量为0.28±0.008 g/L,固氮酶活性为1.09 nmol/(min mg protein), μmax为0.016 h-1。讨论:研究结果揭示了氧气的关键双重作用:高氧水平通过激活pMMO的铜依赖催化位点来促进甲烷氧化,但同时不可逆地破坏对N2固定至关重要的氧敏感型氮酶,抑制其活性。相反,低氧保护了氮酶,但限制了pMMO的效率。这就产生了一种基本的代谢权衡,其中最佳的CH4/O2比例平衡了这些相反的影响,有策略地将细胞能量分配给有效的甲烷同化(有利于高氧)或atp密集型的固氮过程(需要低氧)。这些确定的气比阈值为设计规模化的SCP生物生产系统提供了可操作的参数,通过气相工程实现工业甲烷减排与可持续蛋白质合成的有效耦合。
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引用次数: 0
Distribution and function of prokaryotes involved in mercury methylation, demethylation, and reduction in the western North Pacific Subtropical Gyre. 北太平洋副热带环流西部参与汞甲基化、去甲基化和还原的原核生物的分布和功能。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2025-01-01 DOI: 10.3389/fmicb.2025.1642479
Yuya Tada, Ryota Nakajima, Minoru Kitamura, Kohji Marumoto

Methylmercury (MeHg), a bioaccumulative neurotoxic heavy metal, substantially threatens environmental and human health. In natural environments, MeHg formation and degradation are primarily mediated by microorganisms containing hgcAB, merA, or merB genes. However, these genes have not been simultaneously analyzed in open-ocean samples. This study aimed to investigate the distribution and phylogeny of functional genes associated with mercury (Hg) methylation (hgcA and hgcB), demethylation (merB), and reduction (merA), as well as dissolved total Hg (THg) and MeHg concentrations in the western North Pacific Subtropical Gyre (WNPSG) using metagenomic analysis. Although THg levels varied across sampling sites, MeHg concentrations consistently increased with depth. A strong correlation between dissolved MeHg and apparent oxygen utilization indicated a link between Hg methylation and microbial respiration. hgcA, merB, and merA were predominantly detected at depths of 500-1,500 m, where MeHg concentrations peaked, indicating active microbial Hg speciation within mesopelagic layers. A higher abundance of hgcA than merB suggests that microbial Hg methylation may surpass demethylation in this region. Phylogenetic analyses of hgcAB identified the Nitrospina lineage as dominant Hg methylators. Metabolic pathway analyses of metagenome-assembled genomes (MAGs) showed that Nitrospina harboring hgcAB possesses the nitrite reductase pathway, suggesting a linkage between Hg methylation and nitrogen cycling. MAGs with hgcA affiliated with Myxococcota (Deltaproteobacteria) exhibited a strong association with sulfur cycling. Diverse lineages harboring merB and merA genes were identified, suggesting that MeHg demethylation and Hg(II) reduction likely co-occur. Methanogenesis pathways in some Alphaproteobacteria with merB or merA suggest a potential connection between methane production and MeHg degradation and Hg(II) reduction. These findings provide novel insights into the intricate interactions between microbial communities, functional gene distributions, and Hg biogeochemical cycling in the WNPSG.

甲基汞(MeHg)是一种具有生物蓄积性神经毒性的重金属,严重威胁着环境和人类健康。在自然环境中,甲基汞的形成和降解主要是由含有hgcAB、merA或merB基因的微生物介导的。然而,这些基因并没有同时在公海样本中进行分析。本研究旨在通过宏基因组分析研究北太平洋副热带西部环流(WNPSG)中汞(Hg)甲基化(hgcA和hgcB)、去甲基化(merB)和还原(merA)以及溶解总汞(THg)和甲基汞(MeHg)浓度相关功能基因的分布和系统发育。虽然THg水平在采样点之间有所不同,但MeHg浓度一直随着深度的增加而增加。溶解甲基汞与表观氧利用之间的强相关性表明汞甲基化与微生物呼吸之间存在联系。hgcA、merB和merA主要在500-1,500 m深度检测到,其中MeHg浓度达到峰值,表明中上层微生物Hg物种活跃。hgcA丰度高于merB,表明该区域微生物汞甲基化可能超过去甲基化。hgcAB的系统发育分析表明,亚硝基脊柱谱系是主要的汞甲基化分子。宏基因组组装基因组(MAGs)的代谢途径分析表明,携带hgcAB的Nitrospina具有亚硝酸盐还原酶途径,这表明汞甲基化与氮循环之间存在联系。黏菌门(Deltaproteobacteria)中含有hgcA的MAGs与硫循环密切相关。发现了含有merB和merA基因的不同谱系,表明MeHg去甲基化和Hg(II)还原可能同时发生。一些带有merB或merA的甲变形菌的产甲烷途径表明甲烷的产生与MeHg降解和Hg(II)还原之间存在潜在的联系。这些发现为WNPSG中微生物群落、功能基因分布和汞生物地球化学循环之间复杂的相互作用提供了新的见解。
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引用次数: 0
Polymorphospora lycopeni A560, a new strain capable of producing lycopene, and its optimal fermentation and extraction conditions. 产番茄红素新菌株番茄红素多孢菌A560及其最佳发酵提取条件。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2025-01-01 DOI: 10.3389/fmicb.2025.1723758
Xiaomin Duan, Shilong Li, Yan Li, Zihao Yang, Xiumin Zhang

Background: Lycopene, a vital antioxidant, can reduce oxidative damage to cells caused by reactive oxygen, prevent cancer, lower blood cholesterol levels, and mitigate cardiovascular diseases. We screened a lycopene-producing strain of the genus Polymorphospora, designated A560, and discovered that its metabolic pathway lacks the lycopene β-cyclase gene crtY, which is responsible for converting lycopene into β-carotene. The absence of crtY alleviates the challenges associated with the addition of a cyclooxygenase inhibitor, which previously hindered the large-scale accumulation of lycopene in Blakeslea trispora.

Method: This study was conducted to enhance lycopene production in strain A560 through a multi-stage optimization strategy, focusing on improving extraction efficiency and optimizing culture medium components. The extraction conditions were optimized by testing different solvent systems (acetone/n-hexane/ethanol), extraction temperatures, and durations. Subsequently, a uniform design (UD) was applied to systematically optimize the composition of the culture medium to maximize lycopene yield.

Results: The extraction conditions were systematically optimized. A crushing duration of 4 min was identified as optimal for complete cell disruption. The most efficient solvent system was determined to be n-hexane/ethanol (2:1, v/v) at 60 °C, which yielded 62.05 ± 4.68 mg/L of lycopene-a 37.13% increase over extraction with acetone at room temperature (45.25 ± 0.98 mg/L). Subsequent medium optimization through a uniform design revealed that soluble starch and glycerol were critical components. Cultivation in the theoretically optimized medium predicted by the model resulted in a lycopene yield of 142.54 ± 8.58 mg/L. Finally, regulating the oxygen supply by adjusting the flask's volume of air to a medium volume (Va/Vm) ratio proved crucial. The highest lycopene production of 201.44 ± 6.23 mg/L was achieved at a Va/Vm ratio of 1.5, which marks a 224.64% improvement over the yield obtained after the initial extraction optimization (62.05 ± 4.68 mg/L).

Conclusion: The extraction and fermentation processes for lycopene production in Polymorphospora sp. A560 were successfully optimized, resulting in significantly enhanced yields. These results demonstrate that strain A560 is a promising microbial resource for the fermentative production of lycopene.

背景:番茄红素是一种重要的抗氧化剂,可以减少活性氧对细胞造成的氧化损伤,预防癌症,降低血液胆固醇水平,减轻心血管疾病。我们筛选了一株番茄红素产生菌株,命名为A560,发现其代谢途径缺乏番茄红素β-环化酶基因crtY,该基因负责将番茄红素转化为β-胡萝卜素。crtY的缺失缓解了与添加环加氧酶抑制剂相关的挑战,环加氧酶抑制剂先前阻碍了番茄红素在三孢子中的大规模积累。方法:采用多阶段优化策略,以提高菌株A560番茄红素的提取效率和优化培养基成分为重点,提高菌株A560番茄红素的产量。通过考察不同溶剂体系(丙酮/正己烷/乙醇)、提取温度和提取时间,优化提取条件。随后,采用均匀设计法(UD)对培养基组成进行系统优化,使番茄红素产量最大化。结果:对提取工艺进行了系统优化。4 min的破碎时间被确定为完全细胞破坏的最佳时间。在60 °C条件下,正己烷/乙醇(2:1,v/v)溶剂体系的番茄红素提取率为62.05 ± 4.68 mg/L,比室温条件下丙酮萃取(45.25 ± 0.98 mg/L)的提取率提高了37.13%。随后通过均匀设计的培养基优化表明,可溶性淀粉和甘油是关键成分。在模型预测的理论优化培养基上培养,番茄红素产量为142.54 ± 8.58 mg/L。最后,通过调节烧瓶的空气体积到一个中等体积(Va/Vm)的比例来调节氧气供应被证明是至关重要的。在Va/Vm为1.5的条件下,番茄红素的最高产量为201.44 ± 6.23 mg/L,比初始优化提取后的产量(62.05 ± 4.68 mg/L)提高了224.64%。结论:优化了Polymorphospora sp. A560番茄红素的提取和发酵工艺,显著提高了产量。这些结果表明,菌株A560是一种很有前途的发酵生产番茄红素的微生物资源。
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引用次数: 0
Correction: Peppermint extract improves egg production and quality, increases antioxidant capacity, and alters cecal microbiota in late-phase laying hens. 更正:薄荷提取物提高产蛋率和质量,增加抗氧化能力,改变后期蛋鸡盲肠微生物群。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2025-01-01 DOI: 10.3389/fmicb.2025.1746506
Miaomiao Bai, Hongnan Liu, Yihui Zhang, Shanshan Wang, Yirui Shao, Xia Xiong, Xin Hu, Rongyao Yu, Wei Lan, Yadong Cui, Xiangfeng Kong

[This corrects the article DOI: 10.3389/fmicb.2023.1252785.].

[这更正了文章DOI: 10.3389/fmicb.2023.1252785.]。
{"title":"Correction: Peppermint extract improves egg production and quality, increases antioxidant capacity, and alters cecal microbiota in late-phase laying hens.","authors":"Miaomiao Bai, Hongnan Liu, Yihui Zhang, Shanshan Wang, Yirui Shao, Xia Xiong, Xin Hu, Rongyao Yu, Wei Lan, Yadong Cui, Xiangfeng Kong","doi":"10.3389/fmicb.2025.1746506","DOIUrl":"https://doi.org/10.3389/fmicb.2025.1746506","url":null,"abstract":"<p><p>[This corrects the article DOI: 10.3389/fmicb.2023.1252785.].</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"16 ","pages":"1746506"},"PeriodicalIF":4.0,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12874084/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146141687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of Saccharomyces cerevisiae-lactic acid bacteria cocultured maize silage on dairy cows performance and in vitro rumen fermentation. 酿酒酵母-乳酸菌共培养玉米青贮对奶牛生产性能和体外瘤胃发酵的影响。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2026-01-01 DOI: 10.3389/fmicb.2026.1753173
Qingqing Chen, Zixin Liu, Chuanshe Zhou, Zhiming Zhong, Jian Wu, Aoyu Jiang, Hai Yang, Zhiliang Tan, Bernard Adubwa Lukuyu, Jinhe Kang

Introduction: Microbial additives can improve silage quality in lowland areas. However, Saccharomyces cerevisiae and Lactic Acid Bacteriacan efficacy on whole-plant maize silage under Tibet's hypoxic and cold environment, have not been explored.

Methods: In this experiment, whole corn plants cultivated in Dazi District, Lhasa City, Xizang (Tibet) Autonomous Region, were selected as silage raw materials. The treatment group was added 0.5 kg of microbial additives per ton of silage. The addition levels for both Saccharomyces cerevisiae and Lactic Acid Bacteria were ≥ 1 × 107 CFU·g-1 FM). The quality of silage and its in vitro fermentation characteristics were determined on 0, 30 and 60 days of fermentation, respectively. Subsequently, dairy cows were fed with silage after 60 days of fermentation to evaluate milk production and milk quality.

Results: The results indicated that the lactic acid content in the treatment group was increased significantly on 30 and 60 days of fermentation (p < 0.05). In addition to Simpson's index, alpha diversity was significantly affected by the fermentation day × treatment interaction (p < 0.05). At 60 days of fermentation, the abundance of Firmicutes phylum in the treatment group was significantly higher than that in the control group (p < 0.05). The abundance of genera such as Acetobacter and Latilactobacillus was significantly decreased (p < 0.05), while the abundance of the genus Weissella was significantly increased (p < 0.05). Dairy cows were fed 60-day maize silage, the milk protein content and total solid content in the treatment group were significantly higher than that in the control group (p < 0.05). The levels of dry matter degradation rate, ammonia nitrogen and total volatile fatty acids in the in vitro fermentation of maize silage in the treatment group on the 60th day of fermentation were significantly higher than that in the control group (p < 0.05).

Conclusion: In Xizang (Lhasa, China), the addition of microbial additives has significantly improved the quality and nutritional value of whole corn silage plants and enhanced the milk quality of local dairy cows. This provides a theoretical basis for the application of microbial additives from the Qinghai-Tibet Plateau to agricultural crops.

微生物添加剂可以提高低海拔地区青贮饲料的品质。然而,在西藏低氧低温环境下,酿酒酵母菌和乳酸菌对整株玉米青贮的影响尚未得到深入研究。方法:以西藏(西藏)自治区拉萨市大子区种植的全株玉米为青贮原料。处理组每吨青贮饲料中添加0.5 kg微生物添加剂。酿酒酵母和乳酸菌的添加量均≥1 × 107 CFU·g-1 FM)。分别在发酵第0、30和60天测定青贮品质和体外发酵特性。随后,在发酵60 d后饲喂青贮奶牛,评价产奶量和牛奶品质。结果:发酵30、60 d时,处理组乳酸含量显著升高(p < 0.05)。除辛普森指数外,发酵天数×处理互作对α多样性也有显著影响(p < 0.05)。发酵60 d时,处理组厚壁菌门丰度显著高于对照组(p < 0.05)。Acetobacter、Latilactobacillus等属的丰度显著降低(p < 0.05), Weissella属的丰度显著升高(p < 0.05)。饲喂60日龄玉米青贮的奶牛,处理组乳蛋白含量和总固形物含量显著高于对照组(p < 0.05)。发酵第60天,处理组玉米青贮体外发酵干物质降解率、氨氮和总挥发性脂肪酸水平均显著高于对照组(p < 0.05)。结论:在西藏(中国拉萨),添加微生物添加剂显著提高了全株玉米青贮植株的品质和营养价值,提高了当地奶牛的牛奶品质。这为青藏高原微生物添加剂在农作物中的应用提供了理论依据。
{"title":"Effects of <i>Saccharomyces cerevisiae</i>-lactic acid bacteria cocultured maize silage on dairy cows performance and <i>in vitro</i> rumen fermentation.","authors":"Qingqing Chen, Zixin Liu, Chuanshe Zhou, Zhiming Zhong, Jian Wu, Aoyu Jiang, Hai Yang, Zhiliang Tan, Bernard Adubwa Lukuyu, Jinhe Kang","doi":"10.3389/fmicb.2026.1753173","DOIUrl":"10.3389/fmicb.2026.1753173","url":null,"abstract":"<p><strong>Introduction: </strong>Microbial additives can improve silage quality in lowland areas. However, <i>Saccharomyces cerevisiae</i> and Lactic Acid Bacteriacan efficacy on whole-plant maize silage under Tibet's hypoxic and cold environment, have not been explored.</p><p><strong>Methods: </strong>In this experiment, whole corn plants cultivated in Dazi District, Lhasa City, Xizang (Tibet) Autonomous Region, were selected as silage raw materials. The treatment group was added 0.5 kg of microbial additives per ton of silage. The addition levels for both <i>Saccharomyces cerevisiae</i> and Lactic Acid Bacteria were ≥ 1 × 107 CFU·g-1 FM). The quality of silage and its <i>in vitro</i> fermentation characteristics were determined on 0, 30 and 60 days of fermentation, respectively. Subsequently, dairy cows were fed with silage after 60 days of fermentation to evaluate milk production and milk quality.</p><p><strong>Results: </strong>The results indicated that the lactic acid content in the treatment group was increased significantly on 30 and 60 days of fermentation (<i>p</i> < 0.05). In addition to Simpson's index, alpha diversity was significantly affected by the fermentation day × treatment interaction (<i>p</i> < 0.05). At 60 days of fermentation, the abundance of <i>Firmicutes phylum</i> in the treatment group was significantly higher than that in the control group (<i>p</i> < 0.05). The abundance of genera such as <i>Acetobacter</i> and <i>Latilactobacillus</i> was significantly decreased (<i>p</i> < 0.05), while the abundance of the genus <i>Weissella</i> was significantly increased (<i>p</i> < 0.05). Dairy cows were fed 60-day maize silage, the milk protein content and total solid content in the treatment group were significantly higher than that in the control group (<i>p</i> < 0.05). The levels of dry matter degradation rate, ammonia nitrogen and total volatile fatty acids in the <i>in vitro</i> fermentation of maize silage in the treatment group on the 60th day of fermentation were significantly higher than that in the control group (<i>p</i> < 0.05).</p><p><strong>Conclusion: </strong>In Xizang (Lhasa, China), the addition of microbial additives has significantly improved the quality and nutritional value of whole corn silage plants and enhanced the milk quality of local dairy cows. This provides a theoretical basis for the application of microbial additives from the Qinghai-Tibet Plateau to agricultural crops.</p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":"17 ","pages":"1753173"},"PeriodicalIF":4.0,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12872848/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146141648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Editorial: Soil biodiversity and regenerative agriculture: the path to achieve SDGs. 社论:土壤生物多样性和再生农业:实现可持续发展目标的途径。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2025-01-01 DOI: 10.3389/fmicb.2025.1755391
Anukool Vaishnav, Durgesh Kumar Jaiswal, Jagajjit Sahu
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引用次数: 0
A single-center culture-based study of Helicobacter pylori in Kazakhstan with regional meta-analysis of prevalence and antibiotic resistance. 哈萨克斯坦幽门螺杆菌单中心培养研究及其流行和抗生素耐药性区域荟萃分析
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2026-01-01 DOI: 10.3389/fmicb.2026.1747006
Kaisar Dauyey, Gulnur Zhunussova, Jamilya Kaibullayeva, Yevgeniya Bondar, Arailym Yerzhan, Aliya Medetbekova, Aliya Kaisina, Alma Khabizhanova, Kanat Seitbekov, Yoshio Yamaoka

Background: Helicobacter pylori (H. pylori) is a major gastric pathogen and class I carcinogen that causes chronic gastritis, peptic ulcer, and gastric cancer if left untreated. However, evidence on H. pylori prevalence and antimicrobial resistance in Kazakhstan, a country with a high gastric cancer burden, remains scarce. This study presents the first culture-based epidemiological investigation of H. pylori at a single center in Almaty.

Materials and methods: We conducted a cross-sectional study (2024-2025) of 150 dyspeptic patients in Almaty, Kazakhstan. A subset (n = 148) underwent rapid stool antigen (RAS) testing before gastric biopsy collection. Biopsy samples were cultured, and 86 (57.3%) yielded viable H. pylori isolates. Antimicrobial susceptibility testing by the agar dilution method was performed on these 86 isolates. Demographic and clinical data were analyzed, and a regional meta-analysis was conducted using data from recent studies across Central Asia and Russia to estimate pooled prevalence and clarithromycin resistance.

Results: Among 148 patients tested by RAS, 137 were positive. Resistance rates among 86 isolates were 87.2% to metronidazole, 33.7% to clarithromycin, and 3.5% to amoxicillin; no resistance was detected to minocycline or sitafloxacin. Multidrug resistance (defined as resistance to two or more antibiotics) was observed in 34.8% of isolates. The pooled H. pylori prevalence across Central Asian studies was 70% (95% CI: 59-80%), and pooled clarithromycin resistance was 29% (95% CI: 10-53%).

Conclusion: This study provides the first culture-based evidence of H. pylori infection and antimicrobial resistance in Kazakhstan. The high resistance to metronidazole and clarithromycin suggests a likely lower success of standard triple therapy in Almaty. Absence of resistance to minocycline and sitafloxacin supports their use in rescue regimens. These findings highlight the urgent need for national surveillance, updated treatment guidelines, and integration of molecular resistance monitoring to improve evidence-based management of H. pylori in Central Asia.

背景:幽门螺杆菌(Helicobacter pylori, H. pylori)是一种主要的胃病原体和一类致癌物,如果不及时治疗,可引起慢性胃炎、消化性溃疡和胃癌。然而,在胃癌负担高的哈萨克斯坦,关于幽门螺杆菌患病率和抗菌素耐药性的证据仍然很少。本研究首次在阿拉木图的单一中心进行了基于培养的幽门螺杆菌流行病学调查。材料和方法:我们对哈萨克斯坦阿拉木图的150名消化不良患者进行了横断面研究(2024-2025)。一个亚群(n = 148)在胃活检采集前进行了快速粪便抗原(RAS)检测。活检样本进行培养,86例(57.3%)产生活的幽门螺杆菌分离株。采用琼脂稀释法对86株菌株进行了药敏试验。对人口统计学和临床数据进行分析,并使用中亚和俄罗斯近期研究的数据进行区域荟萃分析,以估计汇总流行率和克拉霉素耐药性。结果:148例患者进行RAS检测,阳性137例。86株菌株对甲硝唑耐药率为87.2%,对克拉霉素耐药率为33.7%,对阿莫西林耐药率为3.5%;对米诺环素和西他沙星均无耐药。34.8%的分离株存在多重耐药(定义为对两种或两种以上抗生素的耐药)。中亚研究中幽门螺杆菌的总患病率为70% (95% CI: 59-80%),克拉霉素耐药性的总患病率为29% (95% CI: 10-53%)。结论:本研究为哈萨克斯坦幽门螺杆菌感染和耐药性提供了第一个基于培养的证据。对甲硝唑和克拉霉素的高耐药性表明,在阿拉木图,标准三联疗法的成功率可能较低。对米诺环素和西他沙星无耐药性,支持在抢救方案中使用。这些发现突出表明,迫切需要开展国家监测、更新治疗指南和整合分子耐药性监测,以改善中亚地区幽门螺杆菌的循证管理。
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引用次数: 0
Single-cell RNA-seq reveals a key role for Vibrio cholerae Mak toxins in Tetrahymena pyriformis killing and bacterial survival. 单细胞RNA-seq揭示了霍乱弧菌Mak毒素在梨状四膜虫杀灭和细菌存活中的关键作用。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2025-01-01 DOI: 10.3389/fmicb.2025.1729243
Jonah M Moon, M Mozammel Hoque, Dana Ronin, Parisa Noorian, Joyce To, Scott A Rice, Diane McDougald, Gustavo Espinoza-Vergara

In the environment, Vibrio cholerae employs multiple strategies to resist predation by heterotrophic protozoa. For example, V. cholerae biofilms release toxic compounds, such as ammonium and pyomelanin, which can kill protists, such as Tetrahymena pyriformis. V. cholerae has also been shown to survive intracellularly and can escape as viable cells inside protozoan-expelled food vacuoles (EFVs). We previously reported that V. cholerae encased in EFVs are hyperinfectious, establishing an important link between anti-protozoal strategies and bacterial virulence. Although the intracellular resistance and escape of V. cholerae in EFVs have been reported, the molecular mechanisms behind this remain poorly understood. Here, we used single-cell transcriptomics of V. cholerae exposed to T. pyriformis and captured a total of 5,344 bacterial cells with heterogeneous gene expression. Cells with the same pattern of gene expression were grouped, resulting in 11 clusters of cells with a unique gene expression profile. Genes encoding outer membrane proteins, F1F0-Na+/H+ ATPase, metabolites, and toxins showed differential expression among the clusters. Furthermore, the motility-associated killing factor (Mak) toxins were differentially expressed. The V. cholerae mutants ΔmakA, ΔmakB, and ΔmakE were not capable of killing T. pyriformis, and ΔmakA and ΔmakE showed reduced survival inside EFVs compared to the wild type. These findings identify Mak toxins as key mediators of V. cholerae resistance to protozoan grazing and survival within EFVs. More broadly, our results provide mechanistic insight into grazing resistance, reveal factors facilitating persistence in EFVs, and underscore the interplay between environmental survival strategies and virulence in pathogenic bacteria.

在环境中,霍乱弧菌采用多种策略来抵抗异养原生动物的捕食。例如,霍乱弧菌生物膜释放有毒化合物,如铵和脓黑素,可以杀死原生生物,如梨状四膜虫。霍乱弧菌也被证明能在细胞内存活,并能作为活细胞从原生动物排出的食物液泡(efv)中逃逸。我们以前报道过包裹在efv中的霍乱弧菌具有高传染性,这在抗原生动物策略和细菌毒力之间建立了重要的联系。虽然已经报道了霍乱弧菌在efv中的细胞内耐药和逃逸,但其背后的分子机制仍然知之甚少。在这里,我们使用了暴露于梨形锥虫的霍乱弧菌的单细胞转录组学,共捕获了5344个具有异质基因表达的细菌细胞。将具有相同基因表达模式的细胞分组,得到11个具有独特基因表达谱的细胞簇。编码外膜蛋白、F1F0-Na+/H+ atp酶、代谢物和毒素的基因在集群中表现出差异表达。此外,运动相关杀伤因子(Mak)毒素也有差异表达。霍乱弧菌突变体ΔmakA、ΔmakB和ΔmakE不能杀死梨形弧菌,与野生型相比,ΔmakA和ΔmakE在efv中的存活率降低。这些发现确定了Mak毒素是霍乱弧菌对efv内原生动物放牧和存活的抗性的关键介质。更广泛地说,我们的研究结果为放牧抗性提供了机制见解,揭示了促进efv持久性的因素,并强调了环境生存策略与致病菌毒力之间的相互作用。
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引用次数: 0
Evaluation of the inhibitory effect of the cell-free fermentation filtrate of Bacillus atrophaeus YL84 on Fusarium oxysporum f. sp. vasinfectum and analysis of its metabolic products. 萎缩芽孢杆菌YL84无细胞发酵滤液对葡萄枯萎病菌抑制效果评价及其代谢产物分析。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2026-01-01 DOI: 10.3389/fmicb.2026.1761389
Yuxin Tang, Zhe Wang, Hongzu Feng, Lan Wang

To evaluate the biocontrol potential of the cell-free fermentation filtrate (CFFF) of Bacillus atrophaeus strain YL84 against Fusarium oxysporum f. sp. vasinfectum (FOV), this study systematically investigated the effects of the CFFF at various dilution ratios on FOV mycelial growth, conidial germination, cellular nucleic acid leakage, and malondialdehyde (MDA) content. Furthermore, the environmental stability of its antifungal activity was assessed. In addition, a dual-culture assay was conducted to evaluate the antagonistic activity of strain YL84 against FOV. The results of the dual-culture assay showed that strain YL84 significantly inhibited the growth of FOV, with an inhibition rate of 81.06%. Subsequently, the YL84 CFFF exerted significant inhibitory effects on FOV mycelial growth and conidial germination across different concentrations, achieving maximum inhibition rates of 75.68% and 77.56%, respectively. Notably, the treated mycelia exhibited a significant increase in cellular nucleic acid leakage and elevated levels of MDA, a product of lipid peroxidation, suggesting that the CFFF may disrupt the integrity of the pathogen's cell membrane. Stability assays revealed that the CFFF possessed substantial tolerance to high temperatures, ultraviolet irradiation, and hypersaline environments, although it remained sensitive to strongly alkaline conditions. Greenhouse pot experiments further confirmed the efficacy of YL84 CFFF in controlling cotton Fusarium wilt, with a maximum control efficacy of 69.21%. Moreover, the treatment induced the upregulation of defense-related enzyme activities in the plants, suggesting that the CFFF may function through both direct antifungal action and the elicitation of host-induced resistance. Component identification via Ultra-Performance Liquid Chromatography-Ion Mobility-Quadrupole Time-of-Flight Mass Spectrometry (UPLC-IMS-Q-TOF-MS) suggested that the filtrate is rich in structurally diverse compounds that were putatively identified as potential antimicrobial substances, predominantly classified as terpenoids and their derivatives. In conclusion, this study provides a systematic evaluation and supporting evidence for the further development of B. atrophaeus YL84 as a biocontrol agent.

为评价萎缩芽孢杆菌菌株YL84无细胞发酵滤液(CFFF)对枯萎病菌丝生长、分生孢子萌发、细胞核酸泄漏和丙二醛(MDA)含量的影响,系统研究了不同稀释倍数下CFFF对枯萎病菌丝生长、分生孢子萌发的影响。并对其抗真菌活性进行了环境稳定性评价。此外,采用双培养法评价菌株YL84对FOV的拮抗活性。双培养实验结果表明,菌株YL84显著抑制FOV的生长,抑制率为81.06%。结果表明,不同浓度的YL84 CFFF对FOV菌丝生长和分生孢子萌发均有显著抑制作用,最大抑制率分别为75.68%和77.56%。值得注意的是,经过处理的菌丝体显示出细胞核酸泄漏和MDA(脂质过氧化产物)水平的显著增加,这表明CFFF可能破坏了病原体细胞膜的完整性。稳定性试验表明,CFFF对高温、紫外线照射和高盐环境具有很强的耐受性,但对强碱性条件仍然敏感。温室盆栽试验进一步证实了YL84 CFFF对棉花枯萎病的防治效果,最高防治效果为69.21%。此外,处理诱导植物防御相关酶活性上调,表明CFFF可能通过直接抗真菌作用和激发宿主诱导的抗性来发挥作用。通过超高效液相色谱-离子迁移-四极杆飞行时间质谱(UPLC-IMS-Q-TOF-MS)的成分鉴定表明,滤液富含结构多样的化合物,这些化合物被认为是潜在的抗菌物质,主要分类为萜类及其衍生物。综上所述,本研究为进一步开发萎缩芽孢杆菌YL84作为生物防治剂提供了系统评价和支持证据。
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引用次数: 0
Unraveling the mechanism of mulberry leaf in alleviating hyperuricemia: key role of kaempferol by modulating AKT pathway and gut-kidney axis. 桑叶减轻高尿酸血症的机制:山奈酚通过调节AKT通路和肠肾轴发挥关键作用。
IF 4 2区 生物学 Q2 MICROBIOLOGY Pub Date : 2026-01-22 eCollection Date: 2026-01-01 DOI: 10.3389/fmicb.2026.1752775
Jiawei Huang, Qianqian Wang, Xiaowen Guo, Yuanyuan Niu, Junhong Huang, Boyi Zhang, Zixuan Guo, Zilong Wang, Shuying Feng

Background: Mulberry leaf (Morus alba L.) is an edible plant that has been found to have medicinal effects in the treatment of hyperuricemia (HUA). The bioactive compounds of mulberry leaf and their mechanisms of action have not been determined yet.

Methods: In-silico methodologies were used to identify bioactive compounds and to determine the underlying mechanisms of mulberry leaf. In order to verify the biochemical mechanism and intestinal microbiota, in vivo experiments were conducted.

Results: Kaempferol was identified as the principal bioactive compound, while the key targets were AKT1 and TNF. Molecular docking and dynamics simulations revealed that AKT1-kaempferol and TNF-kaempferol complexes showed strong and stable binding pattern after a 100 ns simulation. In vivo studies demonstrated that kaempferol exerted significant anti-HUA effects. Specifically, kaempferol reduces AKT expression and phosphorylation, which may in turn reduces the oxidative stress and inflammatory pathways and signal transmission of the kidneys. Meanwhile, the application of kaempferol attenuated gut microbiota dysbiosis caused by HUA.

Conclusion: Kaempferol may regulate UA metabolism and inflammatory injury by modulating the AKT signaling pathway, and exert its effects on the gut-kidney axis and restoring gut microbiota composition.

背景:桑叶(Morus alba L.)是一种可食用植物,已被发现在治疗高尿酸血症(HUA)方面具有药用作用。桑叶的生物活性成分及其作用机制尚未明确。方法:采用计算机方法鉴定桑叶的生物活性成分,并确定桑叶的作用机制。为了验证生化机制和肠道菌群,进行了体内实验。结果:山奈酚为主要生物活性化合物,关键靶点为AKT1和TNF。分子对接和动力学模拟表明,经过100 ns模拟,akt1 -山奈酚和tnf -山奈酚配合物表现出强而稳定的结合模式。体内研究表明山奈酚具有显著的抗hua作用。具体来说,山奈酚可以降低AKT的表达和磷酸化,从而减少肾脏的氧化应激、炎症途径和信号传递。同时,山奈酚的应用减轻了HUA引起的肠道菌群失调。结论:山奈酚可能通过调节AKT信号通路调节UA代谢和炎症损伤,并对肠肾轴和恢复肠道菌群组成发挥作用。
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引用次数: 0
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Frontiers in Microbiology
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