Microbiology Research

14 pages, 14452 KB

Open AccessArticle

Alterations in the Histamine Axis Are Associated with Increased BBB Permeability and Streptococcus suis Invasion

by Yang Wang, Shenao Song, Yingying Quan, Yahao Yu, Zhiheng Chang, Yuxin Wang, Baobao Liu and Li Yi

Microbiol. Res. 2026, 17(9), 174; https://doi.org/10.3390/microbiolres17090174 - 9 Sep 2026

Abstract

Streptococcus suis (S. suis) is a zoonotic pathogen capable of causing meningitis and other diseases. However, the molecular mechanisms underlying its ability to cross the blood brain barrier (BBB) and invade the central nervous system remain incompletely understood. In this study, [...] Read more.

Streptococcus suis (S. suis) is a zoonotic pathogen capable of causing meningitis and other diseases. However, the molecular mechanisms underlying its ability to cross the blood brain barrier (BBB) and invade the central nervous system remain incompletely understood. In this study, non-targeted metabolomics was used to investigate the effects of S. suis type 2 strain HA9801 infection on the metabolic profile of human brain microvascular endothelial cells (hBMECs), and to examine associations between key metabolites and BBB permeability. The results showed that HA9801 infection induced changes in the metabolic profile of hBMECs, with significant enrichment of the histidine metabolism pathway. Notably, several histamine-related metabolites were altered. Changes in HDC and HNMT gene expression, together with alterations in histamine-related metabolites detected by non-targeted metabolomics, were consistent with changes in histamine-related metabolism. These observed metabolic alterations were accompanied by significant accumulation of endogenous histamine, which was accompanied by reduced expression of tight junction protein genes (TJP1, OCLN, and CLDN5) and increased BBB permeability. Moreover, elevated histamine levels were associated with increased invasion and translocation of S. suis across the BBB. This study suggests that S. suis impairs BBB integrity in association with alterations in the host histidine–histamine metabolic axis, which were accompanied by increased histamine levels, reduced expression of tight junction protein genes, and enhanced bacterial invasion and translocation. These findings identify histamine-associated signaling as a potential pathway for further investigation in S. suis-associated BBB dysfunction. Full article

(This article belongs to the Special Issue Bacterial Meningitis: Molecular Epidemiology, Pathogenesis, Diagnostics, and Precision Interventions)

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19 pages, 2884 KB

Open AccessArticle

Distribution of HLA-G Alleles and Oncogenic Viruses in Laryngeal Squamous Cell Carcinoma

by Ljiljana Božić, Aleksandra Šmitran, Maja Travar, Dalibor Vranješ, Aleksandar Martinović, Sanja Jovičić and Aleksandra Knežević

Microbiol. Res. 2026, 17(9), 173; https://doi.org/10.3390/microbiolres17090173 - 7 Sep 2026

Abstract

HLA-G polymorphisms and various oncogenic viruses have been demonstrated in cancers of different anatomical sites. The study aimed to investigate the distribution and potential association of HLA-G alleles and the presence of human papillomavirus (HPV), Epstein–Barr virus (EBV), BK polyomavirus (BKPyV), and JC [...] Read more.

HLA-G polymorphisms and various oncogenic viruses have been demonstrated in cancers of different anatomical sites. The study aimed to investigate the distribution and potential association of HLA-G alleles and the presence of human papillomavirus (HPV), Epstein–Barr virus (EBV), BK polyomavirus (BKPyV), and JC polyomavirus (JCPyV) in laryngeal squamous cell carcinoma (LSCC) tissues. A total of 30 frozen tissues were analyzed using nested PCR for HPV detection and EBV detection and genotyping, and semi-nested PCR for BKPyV and JCPyV. Genotyping of HLA-G and HPV was performed by direct sequencing. HLA-G*01:01:01 predominated among the six alleles detected (p < 0.001). HPV was detected in 12 patients, EBV in 11, BKPyV in two patients, and JCPyV in none. High-risk HPV genotypes (16, 18, 66) were significantly more common in comparison to the low-risk genotype (HPV 6) (p = 0.01). Both EBV genotypes were detected, with EBV-1 predominating. Single infection was detected in nine tissues while co-infection was identified in eight LSCC tissues. HPV/EBV co-infection was the most prevalent finding and this difference was statistically significant (p = 0.03). A correlation of HLA-G alleles and the presence of single or viral co-infection was not found. Further investigations with a larger experimental and control cohort are needed to assess their effect on LSCC development. Full article

(This article belongs to the Section Medical and Veterinary Microbiology)

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16 pages, 6704 KB

Open AccessArticle

Preliminary Study on Bacterial Traits Associated with the Behavioural Responses of Metarhabditis rainai (Nematoda: Rhabditidae) in the Ginger Rhizosphere

by Talita Jessica Mnisi, Ebrahim Shokoohi, Mashilo Matotoka and Peter Masoko

Microbiol. Res. 2026, 17(9), 172; https://doi.org/10.3390/microbiolres17090172 - 5 Sep 2026

Abstract

Interactions between soil bacteria and free-living bacterivorous nematodes influence nutrient cycling, microbial community dynamics, and rhizosphere processes, yet the behavioural responses of nematodes to bacterial traits remain poorly understood. This study investigated the relationship between bacterial phenotypic traits and the behavioural responses of [...] Read more.

Interactions between soil bacteria and free-living bacterivorous nematodes influence nutrient cycling, microbial community dynamics, and rhizosphere processes, yet the behavioural responses of nematodes to bacterial traits remain poorly understood. This study investigated the relationship between bacterial phenotypic traits and the behavioural responses of Metarhabditis rainai isolated from ginger rhizosphere soil in Limpopo Province, South Africa. Three bacterial isolates (Stenotrophomonas chelatiphaga, Bacillus sp., and Aeromonas sp.) were characterized for hemolytic activity, motility, biofilm formation, and gentamicin susceptibility. Molecular analyses of 18S and 16S rDNA confirmed the identities of the nematode and bacterial isolates. Nematode attraction was evaluated using an in vitro feeding preference assay. Significant effects of bacterial isolate, time, and their interaction were detected (p < 0.0001), indicating distinct behavioural responses among treatments. Aeromonas sp. elicited the strongest attraction, followed by Bacillus sp., whereas S. chelatiphaga induced a weaker response. Bacterial phenotypic traits varied among isolates, with Bacillus sp. exhibiting the highest hemolytic activity, motility, and gentamicin resistance. Overall, M. rainai displayed selective attraction toward different bacterial isolates, and these responses coincided with variation in bacterial traits. However, no direct causal relationship between individual bacterial traits and nematode behaviour was established. Full article

(This article belongs to the Special Issue Rhizosphere Processes and Plant–Microbiome Interactions)

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16 pages, 1506 KB

Open AccessArticle

Preliminary Screening of Entomopathogenic Fungi and Semiochemical Compatibility for a Potential Auto-Inoculation Strategy Against Frankliniella occidentalis

by Corentin Descombes, Charles J.-F. Chappuis, Yannick Barth and François Lefort

Microbiol. Res. 2026, 17(9), 171; https://doi.org/10.3390/microbiolres17090171 - 5 Sep 2026

Abstract

Frankliniella occidentalis, an important crop pest worldwide, is mainly controlled by chemical pesticides, triggering resistance in thrips populations. Among the biological control methods evaluated in recent years, entomopathogenic fungi (EPF) appear to be a promising solution. A self-inoculation method could be an [...] Read more.

Frankliniella occidentalis, an important crop pest worldwide, is mainly controlled by chemical pesticides, triggering resistance in thrips populations. Among the biological control methods evaluated in recent years, entomopathogenic fungi (EPF) appear to be a promising solution. A self-inoculation method could be an alternative that would increase specificity and reduce application costs. This requires efficient compatible semiochemicals and available EPF. The present study therefore consists of a preliminary screening of these components and their compatibility. Fungal strains were isolated from thrips cadavers with fungal infection symptoms in thrips populations reared in insect rearing cages. Out of twenty-three isolated fungal strains, one strain (Bb1) of Akanthomyces lecanii showed some efficacy for F. occidentalis biocontrol. Other strains potentially pathogenic to humans were not considered. The pathogenicity of the Bb1 strain and nine other EPF strains from our collection was assessed using an exploratory method in which the fungal treatments were applied to F. occidentalis eggs laid on bean pods. The reduction in the number of surviving individuals in the emerging population was evaluated after 8 days. The Bb1 strain caused a statistically significant mortality of 75%. In addition to that, the ten EPF strains were exposed to seven semiochemicals at concentrations of 1% and 10%. All semiochemicals showed an inhibitory effect. Moreover, geraniol, nerol and linalool at 10% were specifically deleterious, with 41%, 71% and 82% fungal growth inhibition, respectively. However, the inhibitory effect of semiochemicals depends on the strains tested. Thus, the radial growth of strain Bb1 is particularly little affected by verbenone, neryl (S)-2-methylbutanoate, methyl isonicotinate, and p-anisaldehyde. This work yielded a fungal strain of interest and the selection of potentially compatible semiochemicals attractive to F. occidentalis. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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19 pages, 6424 KB

Open AccessReview

Recurrent Vulvovaginal Candidiasis: Risk, Prevention and QoL (2020–2026)

by Sonja M. Novak, Biljana N. Kocić, Maja D. Nikolić, Nikola G. Milenković, Nadežda M. Popović and Nataša K. Rančić

Microbiol. Res. 2026, 17(9), 170; https://doi.org/10.3390/microbiolres17090170 - 3 Sep 2026

Abstract

Recurrent vulvovaginal candidiasis (RVVC), commonly defined as ≥3 symptomatic episodes per year, affects an estimated 138 million women worldwide. This structured narrative review (PubMed/MEDLINE and open-indexed sources, January 2020–July 2026, as well as selected pre-2020 landmark studies) synthesizes epidemiological and metabolic risk factors [...] Read more.

Recurrent vulvovaginal candidiasis (RVVC), commonly defined as ≥3 symptomatic episodes per year, affects an estimated 138 million women worldwide. This structured narrative review (PubMed/MEDLINE and open-indexed sources, January 2020–July 2026, as well as selected pre-2020 landmark studies) synthesizes epidemiological and metabolic risk factors (including SGLT2-inhibitor-associated susceptibility), host immunogenetic and vaginal microbiome mechanisms, emerging preventive pharmacotherapies, and patient-reported outcomes within a unified clinical framework. RVVC arises from interacting host, microbial, metabolic, behavioral, and iatrogenic domains—diabetes-related hyperglycemia, innate immune polymorphisms (MBL2, TLR2), altered bacterial–fungal vaginal communities, and non-albicans Candida in difficult-to-treat cases. Fluconazole maintenance remains a guideline-supported suppressive option but relapse after discontinuation is common; oteseconazole and ibrexafungerp expand prevention choices, while probiotics show inconsistent, low-certainty benefit. RVVC consistently impairs health-related quality of life, sexual function, and mental health and imposes substantial economic burden; regional data from Southeastern Europe underscore diagnostic and access gaps. We propose a multifactorial host–pathogen–microbiome model that favors individualized, diagnosis-driven management and routine incorporation of validated patient-reported outcomes. Research priorities include harmonized case definitions, head-to-head trials of new agents, validated quality-of-life instruments, longer post-treatment follow-up, and real-world cost-effectiveness evaluations. Implementation research, equitable access strategies, clinician education, and national health policy are essential to translate evidence into improved patient outcomes globally. Full article

(This article belongs to the Special Issue Candida Infections: Epidemiology and Impact on the Patient Health-Related Quality of Life)

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14 pages, 656 KB

Open AccessReview

Salmonella Senftenberg: A Highly Adaptable Serovar Across Poultry Production and the Food Chain

by Dubravka Milanov, Marko Pajić, Darko Stefanović and Jelena Vranešević

Microbiol. Res. 2026, 17(9), 169; https://doi.org/10.3390/microbiolres17090169 - 3 Sep 2026

Abstract

Salmonella enterica subspecies enterica serovar Senftenberg comprises a heterogeneous group of nontyphoidal Salmonella strains frequently detected in animal feed, feed ingredients, feed-manufacturing facilities, poultry production, and a wide range of foods. Genomic analyses indicate that S. Senftenberg is polyphyletic, comprising multiple genetically distinct [...] Read more.

Salmonella enterica subspecies enterica serovar Senftenberg comprises a heterogeneous group of nontyphoidal Salmonella strains frequently detected in animal feed, feed ingredients, feed-manufacturing facilities, poultry production, and a wide range of foods. Genomic analyses indicate that S. Senftenberg is polyphyletic, comprising multiple genetically distinct evolutionary lineages and considerable phenotypic variation among isolates. Certain strains exhibit remarkable tolerance to heat, desiccation, and routine cleaning and disinfection procedures, facilitating their persistence in these environments and potentially contributing to transmission through the food chain. Human infections associated with S. Senftenberg range from self-limiting gastroenteritis to invasive disease, while some outbreak-associated isolates have demonstrated resistance to antimicrobials of particular importance in human medicine, adaptation to plant-derived antimicrobial compounds, and unusual virulence profiles. This review examines S. Senftenberg as an example of how adaptive traits can contribute to the persistence of Salmonella under environmental and selective pressures, with emphasis on its occurrence and persistence in poultry production and implications for food safety and public health. Full article

(This article belongs to the Special Issue Zoonotic Bacteria: Infection, Pathogenesis and Drugs—Second Edition)

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21 pages, 5393 KB

Open AccessArticle

Mechanisms Underlying Rhizosphere Nutrient Enrichment Driven by Flowering-Mediated Metabolite–Microbe Interactions in the Monocarpic Bamboo Chimonobambusa opienensis

by Li Zhang, Gang Xu, Lin Li, Mengyao Kong, Ying Cao and Shanglian Hu

Microbiol. Res. 2026, 17(9), 168; https://doi.org/10.3390/microbiolres17090168 - 2 Sep 2026

Abstract

Background: The monocarpic woody bamboo Chimonobambusa opienensis flowers synchronously and undergoes post-flowering senescence, imposing high nutritional demands during reproduction. Field investigations have documented increases in rhizosphere nutrients during bamboo blooming, but the underlying metabolic–microbial mechanisms remain unclear. Methods: Eight biological replicates of flowering [...] Read more.

Background: The monocarpic woody bamboo Chimonobambusa opienensis flowers synchronously and undergoes post-flowering senescence, imposing high nutritional demands during reproduction. Field investigations have documented increases in rhizosphere nutrients during bamboo blooming, but the underlying metabolic–microbial mechanisms remain unclear. Methods: Eight biological replicates of flowering (FD) and non-flowering (NF) C. opienensis across two locations were used to investigate differences in rhizosphere metabolites, microbiota, functional genes, and soil nutrient stoichiometry. A total of 2196 metabolites were identified, including 108 specific to FD and 63 specific to NF. Flowering was associated with metabolic reprogramming: flavonoids (2′,5,6-trimethoxyflavone) and antioxidant metabolites increased, whereas growth-promoting phytohormones and structural maintenance metabolites decreased. This metabolic transition was accompanied by substantial functional reorganization of the rhizosphere microbiome. Ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB), functional guilds associated with nitrification, were selectively enriched in FD rhizospheres, suggesting a shift from carbon-cycle predominance toward nitrogen-activation potential. NF rhizospheres harbored a microbial consortium associated with decomposition and methanogenesis of complex organic matter. In FD rhizospheres, nitrogen and phosphorus contents were significantly higher (p < 0.05). Correlation analyses revealed strong associations among root metabolites, functional microbial guilds, and soil nutrient pools. Conclusions: The rhizosphere metabolite–microbe–nutrient axis is associated with the increased nutrient demands of flowering and may support reproductive success in monocarpic bamboos. A putative “metabolic signals–microbial functions–nutrient supply” interaction network is identified in the flowering rhizosphere, advancing our understanding of perennial clonal plant–microbe interactions during reproductive transitions. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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Graphical abstract

21 pages, 3918 KB

Open AccessArticle

Phytopathogenic Fungi Pestalotiopsis Sensu Lato and Analysis of Their Secondary Metabolites

by Tatiana V. Antipova, Yulia A. Litovka, Valentina P. Zhelifonova, Vsevolod R. Dubovik, Nataliya V. Fomina, Anton A. Timofeev, Elizaveta G. Lukina, Alexander E. Noskov, Sergey N. Smirnov, Rezo Vasadze, Boris P. Baskunov, Qunfang Weng, Mikhail B. Vainshtein, Alexander O. Berestetskiy and Igor N. Pavlov

Microbiol. Res. 2026, 17(9), 167; https://doi.org/10.3390/microbiolres17090167 - 27 Aug 2026

Abstract

The importance of Pestalotiopsis and Neopestalotiopsis species as pathogens of economically important plants is steadily increasing, while knowledge of their phytotoxic metabolites remains limited. Eighteen new strains of pestalotioid fungi were isolated from various plant samples that showed visible symptoms of disease. These [...] Read more.

The importance of Pestalotiopsis and Neopestalotiopsis species as pathogens of economically important plants is steadily increasing, while knowledge of their phytotoxic metabolites remains limited. Eighteen new strains of pestalotioid fungi were isolated from various plant samples that showed visible symptoms of disease. These strains were evaluated morphologically, and phylogenetic analyses of the ITS (internal transcribed spacer) and tub2 (beta-tubulin) gene regions were performed for genotyping. The isolated strains from Castanea sativa wood and nut were assigned to the species Neopestalotiopsis clavispora (six strain) and P. chamaeropis (one strain); four strains of Neopestalotiopsis, and one strain of Pestalotiopsis were not identified at the species level. Five strains isolated from coniferous trees, such as cypress and fir, were assigned to the species P. monochaeta, P. verruculosa, P. hollandica, and N. chrysea. A strain isolated from the Vaccinium uliginosum L. shoot was diagnosed as N. megabetaspora. The pathogenicity of strains was confirmed in vitro on coniferous shoots, Granny Smith apples, and leaves of C. sativa. The most pronounced phytopathogenic properties were demonstrated by strains isolated from C. sativa and a blueberry shoot compared to strains from coniferous trees. The dihydropyrans pestalotin and 7-hydroxypestalotin were identified in these strains, except for P. chamaeropis. The strains, isolated from cypress and fir, mainly produced a range of other metabolites. The extracts of the strains exerted a phytotoxic effect on lettuce root growth, suggesting that the metabolites may be involved in the virulence of the phytopathogenic fungi Pestalotiopsis s.l. Using the extract of Pes21 N. megabetaspora—the most active producer of pestalotins—we demonstrated that the necrosis area on the leaves of V. uliginosum L. and Rubus idaeus L. increased consistently with increasing metabolite concentrations. Purified pestalotin and 7-hydroxypestalotin inhibited lettuce root growth at a concentration of 500 μg/mL and stimulated it at a concentration of 100 μg/mL. This work provides important insights into the regulatory role of metabolites in fungus–plant interactions and serves as a basis for developing new strategies for the maintenance of plant resources. Full article

(This article belongs to the Special Issue Advances in Plant–Pathogen Interactions)

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1 pages, 139 KB

Open AccessCorrection

Correction: Cazares-Benítez et al. A Target to Combat Antibiotic Resistance: Biochemical and Biophysical Characterization of 3-Dehydroquinate Dehydratase from Methicillin-Resistant Staphylococcus aureus. Microbiol. Res. 2024, 15, 2316–2329

by Javier Sebastian Cazares-Benítez, Alfredo Téllez-Valencia, Jesús Oria-Hernández, Adriana Castillo-Villanueva, Erick Sierra-Campos, Mónica Valdez-Solana, Jorge Cisneros-Martínez and Claudia Avitia-Domínguez

Microbiol. Res. 2026, 17(9), 166; https://doi.org/10.3390/microbiolres17090166 - 25 Aug 2026

Abstract

Javier Sebastian Cazares-Benítez was not included as an author in the original publication [...] Full article

14 pages, 2711 KB

Open AccessArticle

Mixed Paulownia and Sugarcane Bagasse Media Enhance Red Pigment Production by Arthrinium phaeospermum: A Potential Role for 4-Methylumbelliferone

by Boxi Chen, Xingbiao Chu, Zihua Su, Haoming Yu and Jianping Sun

Microbiol. Res. 2026, 17(9), 165; https://doi.org/10.3390/microbiolres17090165 - 25 Aug 2026

Abstract

Low-cost lignocellulosic residues offer a sustainable route to fungal pigment production. In this study, six biomass residues were evaluated as culture-medium supplements for Arthrinium phaeospermum, and their chemical constituents that may be associated with enhanced red pigment production were investigated. Fungal growth, [...] Read more.

Low-cost lignocellulosic residues offer a sustainable route to fungal pigment production. In this study, six biomass residues were evaluated as culture-medium supplements for Arthrinium phaeospermum, and their chemical constituents that may be associated with enhanced red pigment production were investigated. Fungal growth, pigment production, and pigment productivity were measured on biomass-amended potato dextrose agar. Following initial screening, Paulownia powder and sugarcane bagasse were selected, and their concentrations were optimized in mixed media. Ethanolic extracts of both materials were characterized using Fourier-transform infrared spectroscopy and ultra-performance liquid chromatography–mass spectrometry, and four major Paulownia-derived compounds were individually evaluated. The optimal medium, containing 4 mg/mL Paulownia powder and 3 mg/mL sugarcane bagasse, produced 3.09 g/L red pigment, representing a 2.02-fold increase over the control. Sugarcane bagasse primarily promoted fungal growth, whereas paulownia enhanced pigment productivity. Among the tested compounds, 0.2 mg/mL 4-methylumbelliferone (4M) showed the strongest stimulatory effect, increasing pigment production 3.01-fold over the control. These findings demonstrate that combining forestry and agro-industrial residues can simultaneously support fungal growth and pigment production. Paulownia-derived coumarins, particularly 4-methylumbelliferone, may contribute to this stimulatory effect and warrant further mechanistic investigation. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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14 pages, 1763 KB

Open AccessArticle

Early Gut and Nasal Bacterial Community Profiles Within 48 h of Birth According to Delivery Mode: Findings from a Mexican Cohort

by Bautista-Carbajal Patricia, García-León Miguel Leonardo, Espinosa-Torres Torija Bogart, Hernández-Pérez Brenda, Rodríguez-Bernabé Alma Angélica, Pérez-Gopar Martha Alicia and Wong-Chew Rosa María

Microbiol. Res. 2026, 17(9), 164; https://doi.org/10.3390/microbiolres17090164 - 22 Aug 2026

Abstract

The earliest gut and nasal bacterial community profiles after birth remain incompletely characterized, particularly when both sites are examined in parallel. We aimed to characterize these profiles according to delivery mode within the first 48 h of life in a Mexican cohort. Meconium [...] Read more.

The earliest gut and nasal bacterial community profiles after birth remain incompletely characterized, particularly when both sites are examined in parallel. We aimed to characterize these profiles according to delivery mode within the first 48 h of life in a Mexican cohort. Meconium and nasal wash samples from 60 neonates (30 vaginal and 30 cesarean deliveries) were analyzed by V3–V4 16S rRNA gene amplicon sequencing on an Illumina MiSeq platform, followed by QIIME 2 processing. All 60 meconium samples yielded analyzable 16S rRNA profiles. Nasal washes yielded analyzable profiles in 10/30 vaginally delivered and 12/30 cesarean-delivered neonates (p = 0.79). No statistically significant differences in alpha diversity were detected by delivery mode in gut samples (observed ASVs, p = 0.842; Shannon index, p = 0.183; Pielou’s evenness, p = 0.121; Faith’s phylogenetic diversity, p = 0.574) or nasal samples (p = 0.356, 0.947, 0.644, and 0.114, respectively). In unadjusted PERMANOVA comparisons, gut community structure differed by delivery mode for Bray–Curtis (p = 0.001), weighted UniFrac (p = 0.021), and unweighted UniFrac (p = 0.013) distances, whereas nasal comparisons were not statistically significant. Traditional ANCOM identified Staphylococcus as the feature with the highest W statistic in cesarean-delivered neonates (W = 65). Descriptive phylum-level profiles were examined across maternal urinary tract infection, premature rupture of membranes, maternal comorbidities, maternal BMI, hours since birth, and recorded antibiotic exposure; these comparisons were not multivariable and cannot exclude residual confounding. Delivery mode was associated with differences in early gut bacterial community structure in this cohort. Nasal findings were inconclusive because only 22 washes yielded analyzable 16S rRNA profiles and the workflow was not optimized to quantify ultra-low-biomass bacterial DNA. These cross-sectional data do not establish persistence, causality, or the timing at which nasal communities become stable. Full article

(This article belongs to the Topic Microbiota Diversity and Its Broader Biological Implications Across Human and Animal Health)

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13 pages, 11452 KB

Open AccessArticle

Potential Role of Po-milR-1 and Its Target Po-3KAT in the Growth, Development and Stress Response of Pleurotus ostreatus

by Yingjuan Li, Danyun Xu and Aimin Ma

Microbiol. Res. 2026, 17(8), 163; https://doi.org/10.3390/microbiolres17080163 - 19 Aug 2026

Abstract

Pleurotus ostreatus is an important edible mushroom, and its growth and development are affected by genetic and epigenetic mechanisms. miRNAs play an important role in fungal epigenetic mechanisms. In previous studies, Po-3KAT was identified as a candidate target of Po-milR-1, and its [...] Read more.

Pleurotus ostreatus is an important edible mushroom, and its growth and development are affected by genetic and epigenetic mechanisms. miRNAs play an important role in fungal epigenetic mechanisms. In previous studies, Po-3KAT was identified as a candidate target of Po-milR-1, and its product was a substrate for ergosterol synthesis. However, the potential relationship between Po-milR-1 and Po-3KAT has not been studied in P. ostreatus. Therefore, this study aims to explore the potential role of Po-milR-1 and Po-3KAT in P. ostreatus. By integrating the Po-milR-1 interference vector into the genome of P. ostreatus, it was found that the mycelial growth rate was accelerated and the fruiting body phenotype changed in the Po-STTM transformants. The expression analysis during development suggested an inverse expression pattern between Po-milR-1 and Po-3KAT. The analysis of qRT-PCR and HPLC showed that 2 mmol/L H₂O₂ promoted the expression of Po-3KAT, and the content of ergosterol increased to 1.17-fold, while 5 mmol/L H₂O₂ inhibited the expression of Po-3KAT, and the content of ergosterol decreased to 0.82-fold. In contrast to oxidative stress, 100 mmol/L and 250 mmol/L salt stress inhibited the expression of Po-3KAT, and the content of ergosterol decreased to 0.87-fold and 0.94-fold, respectively. These results suggest that Po-milR-1 and Po-3KAT may be involved in the regulation of growth, development, and stress responses in P. ostreatus, and may be associated with the change in ergosterol content. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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12 pages, 1646 KB

Open AccessArticle

Rapid Amperometric Assessment of Substrate Oxidation and Acute Toxicant Responses in Acidithiobacillus Strain Thio1

by Alyona Yachkula, Tatiana Kuvichkina, Anton Zvonarev, Tatiana Abashina, Anatoly Reshetilov and Mikhail Vainshtein

Microbiol. Res. 2026, 17(8), 162; https://doi.org/10.3390/microbiolres17080162 - 19 Aug 2026

Abstract

Obligate acidophilic bacteria of the genus Acidithiobacillus are widely used and well known in the biomining industry. Over the past decade, it has been shown that bacterial activity can be determined in short-term experiments via amperometric measurements of microbial oxygen consumption, as changes [...] Read more.

Obligate acidophilic bacteria of the genus Acidithiobacillus are widely used and well known in the biomining industry. Over the past decade, it has been shown that bacterial activity can be determined in short-term experiments via amperometric measurements of microbial oxygen consumption, as changes in the Clark electrode current are proportional to changes in the concentration of dissolved oxygen. This article presents a study of Acidithiobacillus sp. strain Thio1, which was isolated from pyrite–chalcopyrite copper ore and is closely related to A. ferrooxidans. Oxygen consumption by strain Thio1 was measured during the bacterial oxidation of substrates as changes in the electrode current. To evaluate the acute respiratory response of the bacteria to Cu, Zn, and As, respiration suppression was measured at increasing concentrations of the toxicants. The proposed amperometric method is not a substitute for the long-term biogeotechnological evaluation of strain activity using specific ore or pulp samples. At the same time, it can be used as a complementary microbiological method. The proposed approach offers distinct advantages: testing takes mere minutes (rapid analysis), and comparisons of substrates or toxicants can be performed using a single biomass sample (standardization). The amperometric method also demonstrated that oxygen was consumed during the corrosion of solid specimens (steel and chalcopyrite) by Acidithiobacillus sp. strain Thio1. However, applying this method to biocorrosion requires further study because the proportion of oxygen consumption directly related to microbial corrosion remains unknown. Full article

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5 pages, 187 KB

Open AccessEditorial

Host–Microbe Interactions in Health and Disease: Editorial

by Pablo Mendez-Pfeiffer, Josué Juárez and Manuel G. Ballesteros-Monrreal

Microbiol. Res. 2026, 17(8), 161; https://doi.org/10.3390/microbiolres17080161 - 18 Aug 2026

Abstract

Host and microbe interactions continue to drive the trajectory of disease [...] Full article

(This article belongs to the Special Issue Host–Microbe Interactions in Health and Disease)

20 pages, 5358 KB

Open AccessArticle

Dynamics of the Intestinal Microbiota of Zebrafish Under the Influence of a Synbiotic Based on Bacillus subtilis MT74

by Mikhail Nikolaevich Churilov, Maria Sergeevna Mazanko, Evgeniya Valeryevna Prazdnova, Maxim Pavlovich Kulikov, Radomir Viktorovich Skripnichenko, Valeria Vadimovna Vibe, Viktoria Nikolayevna Shevchenko and Dmitry Vladimirovich Rudoy

Microbiol. Res. 2026, 17(8), 160; https://doi.org/10.3390/microbiolres17080160 - 18 Aug 2026

Abstract

The development of probiotic and synbiotic preparations for aquaculture is of considerable practical importance. However, research in this field has typically focused on end-point effects, whereas the dynamics of the interactions between the probiotic, the host, and the intestinal bacterial communities remain insufficiently [...] Read more.

The development of probiotic and synbiotic preparations for aquaculture is of considerable practical importance. However, research in this field has typically focused on end-point effects, whereas the dynamics of the interactions between the probiotic, the host, and the intestinal bacterial communities remain insufficiently characterized. In this study, we evaluated the effect of a synbiotic supplement based on the Bacillus subtilis MT74 strain on the composition of the gut microbiota and gene expression in zebrafish (Danio rerio). Fish received either the synbiotic supplement or equivalent dietary doses of its individual components, namely Bacillus subtilis MT74 culture and inulin. Gut microbial community composition was assessed by 16S rRNA gene amplicon sequencing, and the expression of igf1, hsp70l, gsta.1, lyz, mt2, and b2m was evaluated on days 6, 15, and 30. In addition, the persistence of the studied strain in the gut microbiota after discontinuation of its dietary administration was evaluated. The results revealed multistage changes in gut microbiota composition and host gene expression profiles. These findings indicate that microbiome restructuring and stabilization during dietary intervention are dynamic processes accompanied by changes in host regulatory responses. Full article

(This article belongs to the Special Issue Probiotics and Postbiotics from Animal Sources: From Isolation to Applications in Food and Health)

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25 pages, 5350 KB

Open AccessArticle

Molecular and Phylogenetic Identification of Fungal Taxa Associated with Soybean Anomaly in Brazil

by Lucas Guimarães Ramos, Solange Maria Bonaldo, Gustavo Farias, Carlos Guilherme Theodoro dos Santos, Jeferson Gonçalves de Jesus, Marcio Roggia Zanuzo and Thiago Alexandre Santana Gilio

Microbiol. Res. 2026, 17(8), 159; https://doi.org/10.3390/microbiolres17080159 - 18 Aug 2026

Abstract

Soybean anomaly, characterized by immature pod and grain rot, has been reported in Brazilian soybean production fields, but the fungal taxa associated with symptomatic tissues remain poorly characterized. This study aimed to identify fungi associated with soybean plants showing anomaly symptoms using molecular [...] Read more.

Soybean anomaly, characterized by immature pod and grain rot, has been reported in Brazilian soybean production fields, but the fungal taxa associated with symptomatic tissues remain poorly characterized. This study aimed to identify fungi associated with soybean plants showing anomaly symptoms using molecular and phylogenetic approaches. Symptomatic samples were collected from production fields in Mato Grosso and Rondônia, Brazil. Fungal isolates were obtained from pods, seeds, stems, and leaves, and DNA was extracted for amplification of the ITS and LSU rDNA regions. Sequences were compared with GenBank reference data using BLAST, and phylogenetic analyses were performed using Maximum Likelihood. The analyses revealed isolates belonging to Colletotrichum, Corynespora, Diaporthe, Fusarium, Moniliophthora, Neurospora, Roseograndinia, and Xylaria. Among these, Colletotrichum, Diaporthe, and Fusarium are well-documented soybean pathogens, whereas Corynespora, Moniliophthora, Neurospora, Roseograndinia, and Xylaria remain poorly documented in this host and may represent secondary or opportunistic colonizers. The findings expand molecular information on fungi associated with soybean anomaly in Brazil. However, because pathogenicity tests were not performed, the results should be interpreted as evidence of fungal association with symptomatic tissues rather than confirmation of causality. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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13 pages, 573 KB

Open AccessArticle

Compatibility of Hirsutella citriformis Gum with Entomopathogenic Fungi and Mortality of Bactericera cockerelli (Sulc) (Hemiptera: Triozidae)

by Servando H. Cantú-Bernal, Ricardo Gomez-Flores, Rosa A. Flores-Villarreal, Abigail E. Aguilar-Rocha, César Iván Romo-Sáenz, Emilio Olivares-Sáenz, Patricia Tamez-Guerra, Orquídea Pérez-González and Victor E. Aguirre-Arzola

Microbiol. Res. 2026, 17(8), 158; https://doi.org/10.3390/microbiolres17080158 - 14 Aug 2026

Abstract

Entomopathogenic fungi (EPF) are important microbial agents for sustainable pest management. However, their effectiveness depends on compatible formulations that preserve conidial viability and biological activity. Hirsutella citriformis Speare produces an extracellular gum with potential application as a microbial formulation component. The present study [...] Read more.

Entomopathogenic fungi (EPF) are important microbial agents for sustainable pest management. However, their effectiveness depends on compatible formulations that preserve conidial viability and biological activity. Hirsutella citriformis Speare produces an extracellular gum with potential application as a microbial formulation component. The present study evaluated its short-term compatibility with Beauveria bassiana (Balsamo) Vuillemin and Metarhizium brunneum (Petch) conidia, together with mortality associated with gum-based treatments against Bactericera cockerelli (Šulc), under greenhouse conditions. Conidia were formulated in 0.5% (w/v) gum and applied at 1 × 10⁷ conidia mL⁻¹. Conidial germination remained above 90% and was not affected by gum exposure. Significant treatment effects on mortality were detected for adults and nymphs, using binomial generalized linear models. B. bassiana formulation produced 75.0% and 93.56%, whereas M. brunneum produced 65.2% and 78.2% adult and nymph mortality, respectively. The gum-containing treatment, which included Tween 80, was associated with 44.9% adult and 63.0% nymph mortality. H. citriformis gum therefore showed short-term compatibility with both fungi. However, because we did not include a Tween alone control, mortality may not be specifically attributed to the gum. Further studies will evaluate the basis of this mortality and formulation performance, under storage and field conditions. Full article

(This article belongs to the Section Food and Agricultural Microbiology)

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20 pages, 10600 KB

Open AccessArticle

Clonal Lineage, Not Functional Linkage, Shapes Antimicrobial Resistance Gene, Plasmid Replicon, and Virulence Gene Co-Occurrences in Clinical Cronobacter sakazakii from the United States

by Zhao Chen and Meiwen Cui

Microbiol. Res. 2026, 17(8), 157; https://doi.org/10.3390/microbiolres17080157 - 13 Aug 2026

Abstract

Cronobacter sakazakii is a rare, life-threatening neonatal pathogen. In this study, we profiled antimicrobial resistance genes (ARGs), plasmid replicons, virulence genes, sequence types (STs), and core-genome phylogeny across all publicly available clinical C. sakazakii genomes from the United States (n = 116). [...] Read more.

Cronobacter sakazakii is a rare, life-threatening neonatal pathogen. In this study, we profiled antimicrobial resistance genes (ARGs), plasmid replicons, virulence genes, sequence types (STs), and core-genome phylogeny across all publicly available clinical C. sakazakii genomes from the United States (n = 116). All isolates harbored exclusively chromosomally encoded bla_CSA variants. IncFIB and rep cluster 574 co-occurred in 93.1% of isolates as a conserved backbone among 17 replicon types. Among 49 virulence genes, 13 formed a universal core (flagellar motility and type VI secretion); accessory genes such as the yersiniabactin cluster were sporadic. ARG, plasmid replicon, and virulence gene contents were strongly structured by ST, dominated by ST4, ST1, ST8, and ST13. Stratified testing shows most pairwise associations were confounded by clonal lineage, except the IncFIB-rep cluster 574 co-carriage and an IncFII-hcp/tssD association, significant after ST stratification but not multiple testing correction. Core-genome phylogenetics identified 16 clusters, from a large ST4-dominated group to nine singletons, corroborated by ST monophyly; a genomically identical ST1 pair, nine years apart, indicated long-term clonal persistence. Ancestral state reconstruction distinguished stable single acquisitions from features with repeated turnover. Core-genome and gene-content phylogenies demonstrated substantial discordance despite significant overall correlation. These findings provide a genomic framework for clinical C. sakazakii population structure in the United States. Full article

(This article belongs to the Section Medical and Veterinary Microbiology)

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16 pages, 8760 KB

Open AccessArticle

Phytopathometry of Fungal Diseases Associated with Necrotic Syndrome in Wild Cactus (Pachycereus pringlei) in B.C.S., Mexico

by Ramón Jaime Holguín-Peña, Daniel Ruiz-Juárez, Mónica Gutiérrez-Rojas, Betzabé E. López-Corona, Edgar Omar Rueda-Puente, Wilson Geobel Ceiro-Catasú and Diana Medina-Hernández

Microbiol. Res. 2026, 17(8), 156; https://doi.org/10.3390/microbiolres17080156 - 11 Aug 2026

Abstract

Columnar cacti do not provide direct economic benefits; they are vital for maintaining the ecological balance of flora and fauna in desert ecosystems. Over the past 20 years, necrotic disease has been observed in the southern part of the peninsula, leading to a [...] Read more.

Columnar cacti do not provide direct economic benefits; they are vital for maintaining the ecological balance of flora and fauna in desert ecosystems. Over the past 20 years, necrotic disease has been observed in the southern part of the peninsula, leading to a decline in populations. The infectious nature of the disease associated with cactus necrosis syndrome (CNS) was determined by estimating the incidence, severity, and dispersion index. The pathogenic fungi were studied based on symptoms, dispersion patterns, morphological features, and molecular analysis. To determine the pathogenicity and severity of the isolated fungi, experimental inoculations were performed on small cacti. Results showed that at least five fungi (Phoma spp., Nigrospora sphaerica, Chaetomium spp., Coniochaeta spp., and Alternaria alternata) may be associated with CNS, with responses varying depending on whether infections are mixed or straightforward. Common symptoms included canker and pustules, with prevalence rates of 78.87% and 85.3%, respectively. An increase in incidence of 9.89% was noted compared to 2019 (74.83%) and 2020 (84.72%). The average severity rate for all observed symptoms was 55.21%. These findings identify the causal agents involved in necrotic diseases, which could influence the severity and progression of CNS in B.C.S. Full article

(This article belongs to the Topic Microbial Dynamics in Extreme Environments)

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