Microorganisms

Objectives: To evaluate the epidemiological evolution of unique pneumococcal serotypes covered by either PCV20 or PCV21, common serotypes by both vaccines and non-vaccine serotypes in adults. Methods: We characterized all national IPD clinical isolates from January 2009 to June 2026. Results: The highest burden of IPD was caused by serotypes shared between PCV20 and PCV21 with serotypes 3 and 8 the most prevalent in adults of all ages. During the pre-pandemic period, IPD caused by unique-PCV20 serotypes declined probably due to herd protection by paediatric vaccination with PCVs. In contrast, unique-PCV21 serotypes increased in incidence accounting for more cases than unique-PCV20 serotypes. However, after the COVID-19 pandemic, a different pattern was observed with unique-PCV20 serotypes increasing in incidence due a marked rise in IPD caused by serotypes 4 and 14 that has progressively reduced the gap in disease coverage. In adults aged 18-64 years, the fraction of disease that could be prevented with PCV20/PCV21 changed from 5% in favour of PCV21 (years 2022/2023) to 15% in favour of PCV20 (year 2026) whereas in adults [≥]65 years the vaccine contribution declined from 20% in favour of PCV21 (year 2022) to 8% in 2026. Conclusions: IPD trends in adults have changed after the COVID-19 pandemic, especially in recent years. Our study emphasizes the rapid re-emergence of infections caused by traditional PCV7 serotypes especially serotypes 4 and 14 and reinforce the idea that the use of broader PCVs must be accompanied by an increase in the uptake rates in adults of all ages.

ObjectiveThis study aimed to establish an efficient isolation, culture, and preservation system for lactic acid bacteria from Mongolian horse feces by systematically evaluating the effects of sampling methods, culture conditions, media types, and cryopreservation protocols. MethodsFecal samples were collected using rectal and natural defecation methods, and bacteria were isolated by the spread plate technique, with isolates subcultured and identified via 16S rRNA gene sequencing. The performance of five commercial media (A-E), aerobic versus anaerobic conditions, and different glycerol concentrations (10% and 30%), temperatures (-20 {degrees}C and -80 {degrees}C), and storage durations (7, 15, and 30 days) were compared. ResultsRectal sampling showed significantly higher lactic acid bacterial survival and greater species diversity (12 vs. 8). Anaerobic culture yielded substantially higher counts and diversity (707 strains, 12 species) compared to aerobic conditions (36 strains, 5 species). Medium C (M.R.S. AGAR) exhibited the best isolation performance, producing the highest number of strains (311) and species (11), with selective enrichment for both bacilli and cocci. Glycerol effectively improved strain survival during sample cryopreservation, with the optimal short-term storage ([≤]15 days) achieved at -20 {degrees}C with 30% glycerol. Functional screening of randomly selected strains from optimized conditions demonstrated promising growth, acid and bile salt tolerance, and antimicrobial activity. ConclusionRectal sampling combined with anaerobic incubation using Medium C is recommended for optimal isolation. For samples that cannot be processed immediately, short-term preservation at -20 {degrees}C with 30% glycerol prior to isolation is effective. This study provides practical technical references for the acquisition and preservation of equine intestinal lactic acid bacteria resources.

Extremophilic fungi are a relatively unexplored source of stress-resilient microbes for sustainable agriculture. Here, we describe Talaromyces pseudofuniculosus FAR, isolated from the highly acidic site of Piccolo Inferno in southern Italy and identified by ITS and {beta}-tubulin (BenA) sequencing. Despite its origin from an extreme environment, T. pseudofuniculosus FRA remained fully functional under non-stress conditions and displayed tolerance to salinity and heavy metals while maintaining key plant growth-promoting traits, including phosphate solubilization, auxin-related compound production and hydrolytic activities. In soybean (Glycine max L.), the live fungus promoted plant growth under both non-stress conditions and agriculturally relevant salinity and copper stress, and successfully colonized the roots. A cell-free extracellular extract (exCFS) promoted early seedling development in vitro, but its effects were not sustained in pot experiments. GC-MS analysis provided a qualitative characterization of the extracellular metabolite profile and revealed condition-dependent differences between control, NaCl and CuSO4; growth conditions, indicating environment-dependent modulation of fungal metabolism. Overall, these findings highlight the physiological and metabolic plasticity of T. pseudofuniculosus FRA and support its potential as a fungal biostimulant for saline- and metal-impacted agricultural soils.

Streptococcus anginosus is an opportunistic pathogen causing bacteremia, respiratory tract infections, abscesses, odontogenic infections and has recently been associated with gastric cancer. While numerous genes encoding putative virulence factors have been detected in whole genome sequences, a detailed molecular characterization is missing for most of them. To address putative virulence determinants, we investigated hydrogen peroxide production by S. anginosus and assessed its functional significance for survival in human blood. In Streptococcus pneumoniae the pyruvate oxidase, encoded by the spxB gene, is responsible for H2O2 production and represents a major virulence factor. Interestingly, S. anginosus harbors two genetic variants of the spxB gene, one with high homology to the S. pneumoniae spxB (sequence identity: approx. 94 %) gene, while the other appears to be specific for S. anginosus. Strains carrying the S. pneumoniae variant demonstrate higher H2O2 production (10-20 M) compared to strains harboring the anginosus variant (<1 M). Incubation of S. anginosus strains in human blood showed that bacterial survival was correlated to the amount of hydrogen peroxide production. Assessing H2O2 production in an S. anginosus strain carrying a deletion of the CcpA regulator revealed the control of spxB and H2O2 production by carbon catabolite repression. In conclusion, we found evidence for the presence of a major S. pneumoniae virulence factor in S. anginosus, and we were able to demonstrate that it increases the ability of S. anginosus to survive in human blood.

The obscure life histories of many kickxellalean genera remain a bottleneck for comprehensive taxon sampling and phylogenetic reconstruction of the order. While Kickxellales has long been regarded as saprobes inhabiting soil or dung, the discovery of "amphibious fungi" such as Unguispora, which exhibits dimorphic growth between the animal gut and feces, suggests a cryptic gut-dwelling stage within these genera. Given its phylogenetic proximity to Unguispora, ecophysiological traits of Linderina were investigated to evaluate its potential association with the animal gut. Two isolates of L. macrospora were obtained from Japanese soil, representing the first record of this species in Japan. Physiological assays revealed that the optimal temperature for both vegetative growth and sporulation was 25-30 {degrees}C. Furthermore, comparative growth assays on different media demonstrated that sporocladium abundance per sporangiophore is sensitive to nutrient availability, and nutrient-poor media were determined to be the most suitable for evaluating morphological characterization. Under anaerobic, nutrient-rich conditions which are known to induce yeast-like growth in Unguispora, sporangiospores of L. macrospora produce arthrospores. Although marked morphological plasticity was observed during the arthrospore formation, the occurrence of yeast-like unicellular proliferation suggests a potential relationship with the animal gut. Additionally, vegetative growth and sporulation were markedly inhibited by white light exposure; notably, a lethal effect on growth was observed during incubation at 20 {degrees}C, indicating that the natural niche of the species is restricted to light-shielded environments. Our findings will help to elucidate the cryptic life cycles and evolutionary trajectories within Kickxellales.

Comamonas testosteroni TA441 is a model aerobic steroid-degrading bacterium whose sterane degradation pathway has been elucidated in greater detail than that of any other bacterium to date. Similar pathways have been identified in many bacterial genera, including members of Proteobacteria and Actinomycetota, such as Mycobacterium tuberculosis. Steroid degradation genes in TA441 form an approximately 120-kb mega-cluster, and 40 genes involved mainly in the degradation of the sterane structure and the C20?C22 portion of the side chain at C17 have been identified. Here, we present the complete genome sequence of TA441 together with our findings on its steroid degradation genes. We also compare the genes in the mega-cluster with corresponding genes in other Comamonas strains, ?-Proteobacteria other than Comamonas, ?-Proteobacteria, ?-Proteobacteria, and Actinomycetota using CAGECAT to analyze similarities and differences in steroid degradation genes among these bacteria.

Predatory protists are important in shaping terrestrial microbial ecosystems, but their roles in the phyllosphere, or the communities on aerial plant surfaces, are poorly understood. Previous work found that the order Colpodida dominated heterotrophic protist communities in the phyllosphere. While most protists were sporadically present, a few Colpodida variants were prevalent and abundant, indicating that these variants may represent species adapted to the phyllosphere. To identify these organisms, we cultured colpodids from field-collected tomato leaves and performed phylogenetic analysis of the 18S rRNA gene. Five of nine independent isolates matched the most prevalent Colpodida variant previously identified as leaf-enriched through amplicon sequencing, and these isolates comprised a novel clade of Paracolpoda steinii. When compared to a maize root isolate of Colpoda inflata, an abundant rhizosphere ciliate, a P. steinii isolate was similar in size and growth yield on E. coli, but grew to higher yields and formed large cyst clusters when incubated with model phyllosphere bacteria prey Erwinia and Pseudomonas. We developed and validated quantitative PCR (qPCR) methods for detection and cell abundance estimation of the P. steinii phyllosphere clade, C. inflata, and the order Colpodida in environmental samples. In inoculated greenhouse plants, qPCR-estimated protist populations matched measured inoculum levels, and protist inoculum was still detectable after five days. In an uninoculated tomato field, P. steinii was detected on all plants, with greatest abundances observed in lower leaves and after a rain event. P. steinii comprised up to 18.7% of total leaf Colpodida populations, which were estimated at up to [~]1400 organisms per gram of fresh weight. The findings demonstrate that Colpodida communities are consistently present on tomato leaves, dynamically affected by the abiotic environment, and include significant populations of P. steinii. We propose that the P. steinii isolates and qPCR tools presented can be used as a model system to investigate colonization and distribution patterns, biotic interactions, genetic adaptations, and agricultural applications of leaf predation.

Background Otitis media is a leading cause of childhood morbidity and presents a significant healthcare burden worldwide. Streptococcus pneumoniae is a major aetiological agent of OM, and the introduction of pneumococcal conjugate vaccines into the Malaysian National Immunisation Programme in 2020 would have altered pneumococcal carriage and serotype distribution. This study aimed to determine pneumococcal carriage, serotype distribution, and associated risk factors among children with OM in the early post-PCV era in Peninsular Malaysia. Methods and Findings A total of 360 children with OM were recruited from hospitals on the east and west coasts of Peninsular Malaysia between 2023 and 2025. Nasopharyngeal and middle ear fluid samples were collected for Spn isolation by culture, followed by serotyping using multiplex PCR. Sociodemographic, environmental, and medical history data were analysed for associations with pneumococcal carriage using chi-square, Fishers exact tests, and logistic regression. Pneumococcal carriage was detected in 26.7% of children in either NP or MEF samples, with carriage rates of 25.6% and 1.9% in NP and MEF samples, respectively. The most prevalent serotypes were 23A, 15B/15C, non-typable strains, 19F, and 11A/11D. Daycare attendance (p = 0.012, aOR [95% CI]: 2.177 [1.186 - 3.995] and residence in rural areas (p = 0.019, aOR [95% CI]: 2.476 [1.159 - 5.292] were significantly associated with pneumococcal carriage. The main limitation of the study was the reliance on self-reported questionnaire data, which may have introduced recall bias and reporting errors. Conclusions The predominance of non-vaccine serotypes and non-typable Spn indicates ongoing serotype replacement and the emergence of phase-variant strains in the early post-PCV era. Continued surveillance is essential to monitor these changes and inform the development of next-generation pneumococcal vaccines. This study was registered under clinical trial registration number NCT05429541.

Four rhizobial strains isolated from root nodules of tropical leguminous plants in Costa Rica were characterized. Strain LEGMi-135b was isolated from Lonchocarpus felipei root nodules, LEGMi-12c from Cojoba arborea, LEGMi-198b from Calliandra haematocephala and Rhizobium altiplani LEGMi-166a from Mimosa pigra. Phylogenetic analyses based on the 16S rRNA gene and four concatenated housekeeping genes (recA, atpD, GATase and gyrB) placed these strains within the genera Martinezella (LEGMi-12c, LEGMi-135b, and LEGMi-198b) and Rhizobium (LEGMi-166a). Genome-based analyses showed that strain LEGMi-135b exhibited an average nucleotide identity (ANI) value of 94% and a digital DNA-DNA hybridization (dDDH) value of 53.2% compared with its closest related species, Martinezella hainanensis CCBAU 57015T, supporting its classification as a distinct species. LEGMI-12c exhibited ANI and dDDH values of 98% and 87%, respectively, compared with Martinezella hainanensis CCBAU 57015T. LEGMi-198b showed the highest similarity to Rhizobium cerradonense CNPSo 3464, with ANI and dDDH values of 98% and 81.4%, respectively; however, this taxon has not been validly published. LEGMi-166a exhibited ANI and dDDH values of 100% and 99.3%, respectively, compared with Rhizobium altiplani BR 10423, confirming its assignment to this species. Additionally, differentiation of strains LEGMi-135b and LEGMi-198b from their closest phylogenetic relatives was supported by phenotypic, physiological, and biochemical analyses. Based on the combined genomic, phenotypic, and biochemical evidence, we propose the establishment of the novel rhizobial species Martinezella legmii sp. nov., with strain LEGMi-135b designated as the type strain (LEGMi-135b), and Martinezella ivanii sp. nov., with strain LEGMi-198b designated as the type strain (LEGMi-198b). This study expands our understanding of rhizobial diversity associated with nitrogen-fixing symbioses, particularly among tropical leguminous plants from Costa Rica

This study was carried out on two rabbit lines, each selected for a feed efficiency criterion (growth on restricted feed for the AlimR line or residual consumption on an adlibitum diet for the ConsR line), introduced into a facility by adoption of newborn kits by SPF (specific pathogen free) females. Following this break in symbiotic transmission, fecal samples from females were used to study the microbiota composition of the two lines over seven generations (17 females per line and per generation). The proportion of Firmicutes was significantly higher in the AlimR line than in the ConsR line (82.22% vs 78.21%, p<0.0001). Conversely, the proportion of Bacteroidota was significantly higher in the ConsR line than in the AlimR line (20.38% vs 16.50%, p<0.0001). The effect of generation was also significant for the abundance of Firmicutes and Bacteroidota (p=0.0009 and p<0.0001, respectively). The Shannon diversity index was significantly higher in the AlimR line than in the ConsR line (5.23 vs 5.14, p=0.02). The effect of generation was also significant for the Shannon index (p=0.003). Finally, a discriminant principal component analysis of the microbiota composition allowed us to distinguish both the two lines and the generations, in particular the 11th selected generation (animals adopted by SPF females) and the 18th generation.

Pectobacterium comprises Gram-negative, pectinolytic plant pathogens that cause soft rot and blackleg diseases on numerous economically important crops. During sampling in 2018 in taro (Colocasia esculenta) fields in Hawaii, two bacterial strains PL152T and PL155 were isolated from taro. Peliminary molecular characterization placed both strains in the genus Pectobacterium. However, their taxanomic postions could not be resoved at the species level. A polyphasic taxonomic approach incorporating phenotypic characterization, 16S rRNA gene sequence analysis, multilocus sequence analysis (MLSA), whole genome based phylogeny, average nucleotide identity (ANI), and digital DNA-DNA hybridization (dDDH) was therefore employed to determine their taxonomic status. Phylogenetic and phylogenomic analyses consistently placed PL152 and PL155 together in a distinct and well supported lineage within the genus Pectobacterium, separate from currently recognized species. The two strains exhibited high genomic relatedness to each other, whereas the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values, were lower than the accepted species delineation thresholds of 95% and 70%, respectively, supported the delineation of a novel bacterial species. The genomic characteristic of PL152 included a genome size of 5.02 Mb and a DNA G+C content of 52%. Collectively, based on a polyphasic approach including phylogenetic, phlyogenomic, biochemical, and phenotypic evidences supports the classification of strains PL152 and PL155 as representatives of a novel species within the genus Pectobacterium, for which the name Pectobacterium pacificum sp. nov. is proposed. Strain PL152 (ICMP 2436274, LMG 32536) is designated as the type strain.

Little is currently known about the regulation of PL fimbriae produced by some pathogenic E. coli strains. We identified PlfB, a transcriptional regulator of the PapB family, as a negative regulator of PL fimbriae (Plf). Deletion of plfB significantly increased plfA transcription and Plf production. PlfB bound specifically to the plfA promoter region. Using a PplfA-lux reporter system, the deletion of plfB caused sustained and increased expression across serial passages. Global regulatory genes such as lrp, argR, and hns were also implicated in regulation of plf expression. Loss of lrp or argR decreased plf expression, suggesting these regulators positively regulate PL fimbriae. By contrast, loss of hns increased levels of plf expression, supporting its role as a negative regulator. Interestingly, loss of plfB significantly increased bacterial colonization in the lung of 6-day-old turkey poults. Further, complementation of plfB restored plf fimbrial expression and colonization of turkey lungs to wild-type levels. This further supports an important role for PL fimbriae for colonization of turkey lungs, since loss of plfB which resulted in increased plf gene expression in turkey lungs also correlated with higher bacterial numbers in the lungs. Taken together, these results indicate that PlfB acts as a negative regulator to reduce levels of PL fimbrial expression, under some conditions, but that it is not required for plf expression. This contrasts with the role the PapB regulator, which has been shown to play an essential role in expression of P fimbriae in uropathogenic E. coli strains.

Background: Oral dysbiosis has been associated with oral squamous cell carcinoma (OSCC); however, most microbiome studies rely on 16S ribosomal RNA (rRNA) gene sequencing, limiting species-level taxonomic resolution. Methods: Dental plaque, saliva, and tumor tissue samples from 10 patients with OSCC and dental plaque and saliva samples from 10 healthy controls were analyzed in this exploratory cross-sectional study. DNA was extracted and subjected to shotgun metagenomic sequencing using the Illumina MiSeq platform. Sequence reads were quality filtered with fastp, taxonomically classified using Kraken2 v2.1.3, and species-level abundances were re-estimated with Bracken v2.9 following the removal of human reads and low abundance taxa. Relative abundances were compared using the Mann Whitney U test with the Benjamini Hochberg false discovery rate correction, while the Bray Curtis principal coordinate analysis was used as an exploratory approach to visualize microbial community patterns. Results: Shotgun metagenomic sequencing revealed distinct bacterial community profiles across the oral microenvironment. Dental plaque exhibited the highest taxonomic diversity and relative abundance. The control plaque was enriched in Streptococcus koreensis, Capnocytophaga sp. oral taxon 878, Treponema sp. Marseille Q4132, and Leptotrichia sp. oral taxon 498, whereas the plaque from patients with OSCC showed a higher relative abundance of Pyramidobacter piscolens, Parvimonas parva, and Gemella sanguinis. Salivary samples displayed lower diversity and a more homogeneous composition, predominantly comprising Capnocytophaga endodontalis, Prevotella jejuni, Aggregatibacter aphrophilus, and Gemella sanguinis. The tumor tissue showed relatively higher abundance of Sellimonas catena, Escherichia coli, Solobacterium moorei, and Lacrimispora sp. HJ 01. Conclusions: This exploratory study provides species-level characterization of the oral microbiome across multiple oral microenvironments in OSCC and generates hypotheses for future integrative metagenomic and functional studies investigating the potential contribution of oral bacterial communities to OSCC pathogenesis.

The human gut is home to more than 100 trillion bacteria, where various environmental factors, such as nutrients and gases, exist and influence them. The levels of fermentation gases in the gut, including CO2, fluctuate depending on the host's diet. However, how CO2, an environmental factor, affects the physiological states of gut anaerobes remains poorly understood, but CO2 is often utilized in their cultivation. Akkermansia muciniphila (A. muciniphila) is widely studied as a beneficial human gut microbe. However, the effects of CO2 on the physiological state of A. muciniphila are not fully understood. In this study, we focused on CO2 as an environmental factor and aimed to clarify how CO2 affects the physiological state of A. muciniphila. Culture experiments showed that compared with the absence of CO2, the presence of CO2 significantly increased the growth of A. muciniphila. The results of the metabolomic analysis revealed distinct metabolic profiles in the presence or absence of CO2. The tracing analysis using stable 13C-labelled CO2 demonstrated that CO2 was incorporated into various metabolites in the TCA cycle, the de novo purine/pyrimidine synthesis pathways, and other pathways. In addition, the activity of pyruvate carboxylase, which catalyses an anaplerotic reaction involving CO2 fixation to supply oxaloacetate (OAA) to the TCA cycle, was significantly higher in A. muciniphila cells grown in the presence of CO2. Moreover, supplementation with OAA increased the growth of A. muciniphila in a dose-dependent manner, mirroring the effects of CO2 supplementation. These findings suggest that A. muciniphila utilizes CO2 for an anaplerotic reaction in the TCA cycle and other pathways involving CO2 incorporation, facilitating metabolic flux to promote its robust growth.

The genus Xanthomonas comprises a phylogenetically and ecologically diverse group of bacteria, historically characterized by economically important plant-pathogenic members affecting a wide range of agricultural crops. However, an increasing number of non-pathogenic and endophytic lineages have been recognized within the genus, expanding understanding of its taxonomic and ecological breadth. While it has been known for the last 30 years that non-pathogenic Xanthomonas (NPX) are present in diverse plants, studies from our lab over the last decade on the rice microbiome have revealed the presence of multiple, diverse NPX species as a community associated with a particular plant host. In this study, we identify two novel citrus plant-associated NPX species and provide evidence for the existence of an NPX community composed of multiple, diverse species, as in rice. Biochemical analysis, along with phylogenomic and genome-based taxonomic investigations, revealed that these strains represent two novel species within the genus Xanthomonas, providing evidence for a citrus-associated NPX community composed of multiple, diverse species, analogous to that described in rice. The lack of a canonical type III secretion system, along with multiple antimicrobial biosynthetic loci, as in the rice NPX community, points to their importance in plant microbiomes. Hence, such systematic studies of the NPX community need to be extended to all other plants. Accordingly, we propose that strain LMG 8992 (DSM =122509T) be classified as a novel species, Xanthomonas pateli sp. nov., and strain LMG 8993 (DSM = 122444T) be classified as a novel species, Xanthomonas hingoranii sp. nov.

The bile acid-converting Peptacetobacter hiranonis is a Gram-positive, anaerobic, potentially spore-forming bacterium. It was first isolated from human feces and was subsequently shown to convert bile acids (BA) in both in vitro and in vivo experiments. The conversion of BA relies on the presence of the 7alpha-dehydroxylation multi-step pathway, encoded by the BA-inducible (bai) operon, harbored by P. hiranonis. In companion animals, P. hiranonis has been characterized as a biomarker for intestinal health, with its loss associated with dysbiosis. However, characterization of P. hiranonis cultured from companion animals is limited. An in-depth characterization of P. hiranonis was published by Chen et al. recently, including the proposal of a new species, Peptacetobacter hominis. We have sequenced the whole genome of both canine- and feline-derived strains of P. hiranonis, characterized these strains biochemically, and assessed their in vitro BA-converting ability as well as their antimicrobial resistance profiles. The strains described here can convert primary into secondary BAs and are whole-genome inhibited by low concentrations of amoxicillin-clavulanate, cefepime, ceftriaxone, chloramphenicol, ciprofloxacin, clindamycin, and metronidazole. Based on whole genome analysis, we propose dividing P. hiranonis into two host-adapted subspecies: P. hiranonis subsp. deconjugans and P. hiranonis subsp. nondeconjugans, based on their genomic differences and divergent ability to deconjugate BAs; a function that appears widely distributed among P. hiranonis strains cultured from dogs, but absent from those cultured from cats. Taken together, our results confirmed the BA conversion ability of P. hiranonis cultured from dogs and cats and reveal host-associated genomic and functional differences within the species.

Plant growth-promoting bacterial endophytes represent a sustainable strategy for enhancing agricultural productivity while reducing reliance on synthetic fertilizers and pesticides. This study focused on the genomic and functional characterization of two endophytic bacterial strains, R11F and R19M, isolated from bean and maize roots, respectively. Comparative analyses based on 16S rRNA gene sequences, average nucleotide identity (ANI), and genome-to-genome distance calculations (GGDC) classified both isolates as Pseudomonas palleroniana. Comparative genomic analyses revealed highly conserved genomes containing genes associated with plant colonization, phosphate solubilization, stress adaptation, heavy metal resistance, and hydrocarbon degradation. Genome mining further identified 17 and 18 biosynthetic gene clusters (BGCs) in R11F and R19M, respectively, including non-ribosomal peptide synthetases (NRPS), pyoverdine, NRP-metallophores, RiPP-like compounds, arylpolyenes, {beta}-lactones, terpenes, NAGGN, and hydrogen cyanide. Strain-specific BGCs associated with syringomycin and viscosin biosynthesis were identified in R11F, whereas R19M harbored clusters related to asplenin and kolossin biosynthesis. In vitro assays confirmed indole production, phosphate solubilization, and siderophore production, as well as the ability of both strains to grow in nitrogen-free medium. Both strains significantly inhibited the growth of Fusarium oxysporum, Phytophthora cinnamomi, and Colletotrichum gloeosporioides. Furthermore, plant inoculation assays demonstrated host-dependent growth promotion, with R11F showing the most consistent improvements in plant growth parameters in tomato, wheat, and lentil. Overall, the integration of comparative genomics and experimental validation demonstrates that P. palleroniana R11F and R19M possess complementary traits associated with plant growth promotion, pathogen suppression, saline stress adaptation, and bioremediation.

Marine macroalgae host endophytic microbial communities that serve as valuable reservoirs for drug discovery. In this study, the endophytic actinomycete Streptomyces sp. UL09 was isolated from the internal thallus tissues of the green macroalga Ulva rigida C. Agardh. Fermentation of strain UL09 yielded the nitrobenzoyl sesquiterpenoids insulicolide B (1.63 mg/L) and insulicolide C (1.79 mg/L). The planar structures of compounds 1 and 2 were assigned as insulicolides B and C, respectively, via spectroscopic analysis and comparison with literature data. In vitro bioassays revealed moderate activity against Gram-positive bacteria (MIC 128-512 g/mL), including MRSA Sp3 (MIC 128-256 g/mL). These compounds exhibited cytotoxic activity against human cancer cell lines (HeLa, HepG2, and MDA-MB-231) with IC50 values ranging from 34.35 to 142.64 g/mL. Both compounds demonstrated lower cytotoxicity toward non-malignant Vero cells. Molecular docking simulations predicted that both metabolites target the catalytic ATP-binding cleft of human Polo-like kinase 1 (Plk1), with insulicolide B displaying a favorable docking score ({Delta}G = -9.273 kcal/mol). Furthermore, pkCSM predicted high intestinal absorption and no alerts for the assessed toxicity endpoints. These findings establish Streptomyces sp. UL09 as a viable alternative biological source of insulicolides B and C, highlighting their potential as leads for oncology applications.

Orientia tsutsugamushi is the causative agent of scrub typhus infection in humans. This pathogen is transmitted into mammalian hosts including humans through Leptotrombidium mites. Till date, detection of O. tsutsugamushi in human was performed using PCR assay with 56kDa type specific antigen (TSA56), 47kDa outer membrane protein (47kDa-OMP) and groEL chaperonin gene. To understand the efficiency of different genes for the detection of O. tsutsugamushi in Leptotrombidium mites, we performed a comparative PCR assay with various universal primers targeting different genes including TSA56, 47kDa-OMP and groEL gene. We have collected 500 Leptotrombidium mites from Vellore, Tamil Nadu and, the mites were segregated into 50 pools with 10 mites in each pool were used for DNA extraction. The molecular detection of O. tsutsugamushi was performed using PCR assays (including conventional, nested and duplex PCR). The comparative PCR analysis showed nested PCR of groEL gene has high efficiency in detecting the presence of O. tsutsugamushi in chigger samples compared to other genes. Interestingly, groEL target demonstrated high efficiency for detection of O. tsutsugamushi in chigger samples and, when used with nested primers, can facilitate differentiation of O. tsutsugamushi from other rickettsial pathogens. Thus, we conclude groEL gene nested PCR assay can be used routinely to detect O. tsutsugamushi in trombiculid mites.

Currently, the fungal class Paraglomeromycetes (phylum Glomeromycota) consists of one order, Paraglomerales, with two families: Paraglomeraceae, comprising the genera Paraglomus with ten species and Innospora with one species, and the monogeneric and monospecific Pervetustaceae represented by Pervetustus with Pe. simplex. However, our morphological analyses of these species and an undescribed specimen morphologically resembling other Paraglomeromycetes species, as well as analyses of sequences of these fungi and environmental sequences, indicated that the current taxonomic composition of this class should be updated. We did so here by creating in Paraglomeromycetes Pervetustales ord. nov. with Pervetustus and Opikia catenata gen. nov. and sp. nov., as well as transferring Innospora with In. majewskii to Innosporaceae fam. nov. These novelties were introduced primarily based on strong genetic divergences of the analyzed taxa, as many morphological and histochemical features of their spores and mycorrhizal structures overlap. Only Op. catenata possesses the unique trait of occasionally producing spores in chains. This mode of sporulation has also not been recognized in any other Glomeromycota species. Unlike species of Pervetustales and Innosporaceae, which produce single-walled spores, the subcellular spore structure of Paraglomus species contains one or two walls.