16S rRNA Gene Research Articles

Two new species of Dulcicalothrix (Nostocales, Cyanobacteria) from India and erection of Brunnivagina gen. nov., with observations on the problem of using multiple ribosomal operons in cyanobacterial taxonomy.

Two new species of Dulcicalothrix, D. adhikaryi sp. nov. and D. iyengarii sp. nov., were discovered in India and are characterized and described in accordance with the rules of the International Code of Nomenclature for algae, fungi, and plants (ICN). As a result of phylogenetic analysis, Calothrix elsteri is reassigned to Brunnivagina gen. nov. During comparison with all Dulcicalothrix for which sequence data were available, we observed that the genus has six ribosomal operons in three orthologous types. Each of the three orthologs could be identified based upon indels occurring in the D1-D1' helix sequence in the ITS rRNA region between the 16S and 23S rRNA genes, and in these three types, there were operons containing ITS rRNA regions with and without tRNA genes. Examination of complete genomes in Dulcicalothrix revealed that, at least in the three strains for which complete genomes are available, there are five ribosomal operons, two with tRNA genes and three with no tRNA genes in the ITS rRNA region. Internal transcribed spacer rRNA regions have been consistently used to differentiate species, both on the basis of secondary structure and percent dissimilarity. Our findings call into question the use of ITS rRNA regions to differentiate species in the absence of efforts to obtain multiple operons of the ITS rRNA region through cloning or targeted PCR amplicons. The ITS rRNA region data for Dulcicalothrix is woefully incomplete, but we provide herein a means for dealing with incomplete data using the polyphasic approach to analyze diverse molecular character sets. Caution is urged in using ITS rRNA data, but a way forward through the complexity is also proposed.

DNA stable isotope probing reveals the impact of trophic interactions on bioaugmentation of soils with different pollution histories

BackgroundBioaugmentation is considered a sustainable and cost-effective methodology to recover contaminated environments, but its outcome is highly variable. Predation is a key top-down control mechanism affecting inoculum establishment, however, its effects on this process have received little attention. This study focused on the impact of trophic interactions on bioaugmentation success in two soils with different pollution exposure histories. We inoculated a 13C-labelled pollutant-degrading consortium in these soils and tracked the fate of the labelled biomass through stable isotope probing (SIP) of DNA. We identified active bacterial and eukaryotic inoculum-biomass consumers through amplicon sequencing of 16S rRNA and 18S rRNA genes coupled to a novel enrichment factor calculation.ResultsInoculation effectively increased PAH removal in the short-term, but not in the long-term polluted soil. A decrease in the relative abundance of the inoculated genera was observed already on day 15 in the long-term polluted soil, while growth of these genera was observed in the short-term polluted soil, indicating establishment of the inoculum. In both soils, eukaryotic genera dominated as early incorporators of 13C-labelled biomass, while bacteria incorporated the labelled biomass at the end of the incubation period, probably through cross-feeding. We also found different successional patterns between the two soils. In the short-term polluted soil, Cercozoa and Fungi genera predominated as early incorporators, whereas Ciliophora, Ochrophyta and Amoebozoa were the predominant genera in the long-term polluted soil.ConclusionOur results showed differences in the inoculum establishment and predator community responses, affecting bioaugmentation efficiency. This highlights the need to further study predation effects on inoculum survival to increase the applicability of inoculation-based technologies.9HmCi-USiFQRck8tFgyMqrVideo

Population and genetic diversity of rhizobia nodulating chickpea in Indo-Gangetic plains of India.

Chickpea is a crucial leguminous crop and India is the leading producer, with an average yield of 1.18 tons/ha. It is renowned for its specific nodulation with rhizobia. Despite its significance, studies on chickpea-nodulating rhizobia often focused on small-scale investigations within restricted geographical areas. This study delves into the population, genetic diversity, and symbiotic efficiency of chickpea-nodulating rhizobia in the Indo-Gangetic Plains (IGP) of India. The study revealed a low population of chickpea rhizobia (ranging from 11 to 565 cells/g dry soil) across the examined area. Only three samples exhibited a population exceeding 300 cells/g, emphasizing the potential need for inoculation of rhizobia with efficient and competitive strains. Correlation analysis highlighted a significant positive correlation between rhizobial population and organic carbon content, among various soil parameters like pH, electrical conductivity, available nitrogen (N), phosphorus (P), potassium (K), and organic carbon content. Among the 79 presumptive rhizobia isolated from 24 IGP locations, 61 successfully nodulated chickpea cultivar Pusa 362. 16S rRNA gene sequencing categorized 54 isolates as Mesorhizobium, four as Rhizobium, and three as Ensifer. Genetic diversity assessed by BOX-PCR revealed sixteen distinct banding patterns, underscoring substantial variability among the strains. The strains exhibited plant growth-promoting activities, salt tolerance up to 3% NaCl, and pH tolerance between 4 and 10. Six symbiotically efficient strains were identified based on their positive impact on nodulation and dry biomass. This study provides crucial insights into the diversity, genetic makeup, and symbiotic efficiency of chickpea rhizobia in the IGP, supporting the potential use of indigenous rhizobia for sustainable chickpea productivity in the region.

Peritoneal dialysis-associated peritonitis caused by Tsukamurella inchonensis: a case report and literature review

BackgroundPeritoneal dialysis (PD)-associated peritonitis is a serious complication that can lead to PD discontinuation and mortality. Tsukamurella species are uncommon opportunistic pathogens that can cause peritonitis, often necessitating catheter removal.Case presentationA 46-year-old woman with a 1.5-year history of PD presented with fever and lower abdominal pain, along with cloudy peritoneal effluent showing an elevated cell count. Empiric antibiotic therapy with ciprofloxacin, cefazolin, and ceftazidime was started for PD-associated peritonitis. The peritoneal effluent culture yielded a gram-positive rod with weak acid-fast staining. A rebound in the cell count necessitated a switch of antibiotics to meropenem and vancomycin. This led to improvement, and the treatment was switched to oral levofloxacin on day 30 and the patient was discharged on day 35. Subsequently, 16S rRNA gene sequencing confirmed the isolate as Tsukamurella inchonensis.ConclusionThis case highlights the challenges in identifying and treating Tsukamurella peritonitis. Successful treatment without catheter removal in this case suggests that early detection and appropriate antibiotics may enable catheter salvage in this rare infection. However, further research is needed to establish optimal treatment strategies.

Microbiological and molecular profile of furcation defects in a population with untreated periodontitis.

To describe the microbiological composition of subgingival dental plaque and molecular profile of gingival crevicular fluid (GCF) of periodontal furcation-involved defects. Fifty-seven participants with periodontitis contributed with a degree II-III furcation involvement (FI), a non-furcation (NF) periodontal defect and a periodontally healthy site (HS). Subgingival plaque was analysed by sequencing the V3-V4 region of the 16S rRNA gene, and a multiplex bead immunoassay was carried out to estimate the GCF levels of 18 GCF biomarkers. Aiming to explore inherent patterns and the intrinsic structure of data, an AI-clustering method was also applied. In total, 171 subgingival plaque and 84 GCF samples were analysed. Four microbiome clusters were identified and associated with FI, NF and HS. A reduced aerobic microbiota (p = .01) was detected in FI compared with NF; IL-6, MMP-3, MMP-8, BMP-2, SOST, EGF and TIMP-1 levels were increased in the GCF of FI compared with NF. This is the first study to profile periodontal furcation defects from a microbiological and inflammatory standpoint using conventional and AI-based analyses. A reduced aerobic microbial biofilm and an increase of several inflammatory, connective tissue degradation and repair markers were detected compared with other periodontal defects.

Momordica charantia Is a Novel Host of 'Candidatus Phytoplasma malaysianum'-Related Strains Associated with Bitter Melon Stem Fasciation Disease in China.

Momordica charantia, also known as bitter melon, bitter gourd, and bitter squash, is a member of the Cucurbitaceae family and is widely grown in tropical and subtropical regions for its edible fruit and medicinal properties (Alves et al. 2017). In April 2022, bitter melon plants exhibiting stem fasciation and excessive tendril symptoms were observed in a 50-acre vegetable farm in Yijia Village, Weishan Yizu Huizu Autonomous County, Dali, Yunnan Province, China (Fig. 1). The farm primarily grew tomatoes, but around 400 bitter melon plants were planted in spots where tomatoes failed to establish. One plot had a 40% incidence rate, with four out of ten bitter melon plants showing symptoms. Scattered cases were observed in other plots, leading to an overall disease incidence rate of around 2% for the entire farm. Phytoplasma infection was suspected due to symptomatic plants growing in the same province as previously reported cases of phytoplasma diseases, such as happy tree (Camptotheca accuminata) witches'-broom disease, and the presence of phytoplasma-transmitting leafhoppers (Qiao et al. 2023). DNA was extracted from four symptomatic samples and two healthy controls collected from the abovementioned plot with a 40% disease incidence using Bioteke's Plant Genomic DNA Extraction Kit and then tested for phytoplasma infection. A nested PCR assay was conducted using primer pair P1/16S-SR followed by P1A/16S-SR to amplify the near full-length phytoplasma 16S rDNA (about 1.5kb) as previously described (Lee et al. 2004). None of the healthy controls tested positive for phytoplasma infection, while three out of four symptomatic plants showed positive results. The amplicons from the nested PCR were cloned into the pCRII-TOPO vector as previously described (Lee et al. 2004). The resulting clones were sequenced, and the representative sequence was deposited into GenBank (accession number PP489216). The iPhyClassifier (Zhao et al. 2009) was employed to determine the phytoplasma species and group/subgroup associated with the bitter melon stem fasciation (BMSF) disease. The results indicated that the diseased bitter melon plants were infected with a strain related to 'Candidatus Phytoplasma malaysianum' (EU371934), with a 98.07% sequence identity. The similarity coefficient was 1.00 compared to the reference strain of 16SrXXXII-D (GenBank accession: MW138004). The phytoplasma strain associated with BMSF disease was designated as BMSF1. In addition, the same DNA samples underwent further characterization of the BMSF strains. A nested PCR was conducted using primer pair rpL2F3/rpIR1A, followed by rp(III)-FN/rpIR1A to amplify a phytoplasma-specific rp gene segment (about 1.2 kb) (Martini et al. 2007; Davis et al. 2013). Three out of four samples tested positive, consistent with the 16S rRNA gene amplification results. Similarly, a primer pair L15F1/MapR1 followed by secYF1(III)/secYR1(III) was used to amplify a phytoplasma-specific partial spc operon (about 1.7 kb) that includes the complete secY gene and partial rpl15 and map genes, as previously described (Lee et al. 2010). The obtained rp and partial spc amplicons were cloned and sequenced (GenBank accession numbers PP464295 and PP464296). The rp and secY gene sequences were searched against the non-redundant nucleotide collection in the NCBI database using BLASTN. The top hit for the rp gene was 'Ca. Phytoplasma luffae' (CP054393), with 83.24% identity (1068/1283 base-matching). The top hit for the secY gene was also 'Ca. Phytoplasma luffae' (CP054393), with 72.53% identity (1294/1784 base-matching). The percent identity of the BMSF sequences compared to the top hit is low since no other group 16SrXXXII rp and secY gene sequences are available for comparison. A subgroup 16SrXXXII-D phytoplasma strain has been previously reported associated with Camptotheca acuminata witches'-broom (Qiao et al. 2023) and Trema tomentosa witches'-broom (Yu et al. 2021) in China. To our knowledge, bitter melon represents a new host of 'Candidatus Phytoplasma malaysianum'-related strains, and this is the first report of BMSF disease in China. The findings suggest that 'Candidatus Phytoplasma malaysianum'-related strains infect not only ornamental plants but also crops.

Prevalence and molecular characterization of ticks infesting dogs in Agartala, Tripura

Due to its ability to spread disease from one host to another, tick infestation is the most frequent issue pet owners’ deal with and should be taken seriously. The goal of the current study was to ascertain the prevalence of tick infestation in dogs in Agartala as well as its molecular identity and characterisation. A total of 1776 dogs of various breeds, ages, sexes, and categories were included in the study, which was conducted from March 2022 to February 2023 over the course of a calendar year. The total prevalence of ticks was reported to be 62.12%. According to study on breed, sex, age, and category, German spitz, male dogs, dogs under 1 year of age and stray dogs had the highest frequency of tick infestation. All throughout the year, tick infestations were seen, with the monsoon season seeing the highest frequency. Based on 16S rRNA gene amplification and sequence analysis, molecular identification revealed that all isolated ticks were members of the Rhipicephalus sanguineus species. Using a subset of the 16S rRNA gene, phylogenetic analysis revealed that R. sanguineus (OR244468.1) from Agartala (TrRS-PB) was part of the same clade as isolates from Kerala and Assam.

Integrated Histological and Molecular Analysis of Filarial Species and Associated Wolbachia Endosymbionts in Human Filariasis Cases Presenting Atypically in Thailand.

Atypical presentations of filariasis have posed diagnostic challenges due to the complexity of identifying the causative species and the difficulties in both diagnosis and treatment. In this study, we present the integrative histological and molecular analysis of seven atypical filariasis cases observed in regions of nonendemicity of Thailand. All filariasis cases were initially diagnosed based on histological findings. To confirm the causative species, molecular characterization based on both filarial mitochondrial (mt 12S rRNA and COI genes) and nuclear ITS1 markers was performed, together with the identification of associated Wolbachia bacterial endosymbionts. Among the cases studied, Brugia pahangi (N = 3), Brugia malayi (N = 1), Dirofilaria sp. "hongkongensis" (N = 2), and a suspected novel filarial species genetically related to Pelecitus copsychi (N = 1) were identified. By targeting the 16S rRNA gene, Wolbachia was also molecularly amplified in two cases of infection with Dirofilaria sp. "hongkongensis." Phylogenetic analysis further revealed that the detected Wolbachia could be classified into supergroups C and F, indicating the high genetic diversity of this endosymbiont in Dirofilaria sp. "hongkongensis." Furthermore, this study demonstrates the consistency between histological findings and species identification based on mitochondrial loci rather than on the nuclear ITS1. This suggests the utility of mitochondrial markers, particularly COI, as a highly sensitive and reliable diagnostic tool for the detection and differentiation of filarial species in clinical specimens. Precise identification of the causative species will facilitate accurate diagnosis and treatment and is also essential for the development of epidemiological and preventive strategies for filariasis.

Associations of upper respiratory mucosa microbiota with Rheumatoid arthritis, autoantibodies, and disease activity.

The lung is recognized as a site for initiating the formation of self-antigen and autoimmune responses in rheumatoid arthritis (RA). We aimed to investigate the association of upper respiratory microbiota with RA, autoantibody production, and disease activity. Forty-six patients with RA and 17 controls were examined. Nasopharyngeal swab samples were sequenced for microbiome profiling using the V3-V4 region of the 16S rRNA gene. The microbial diversity and relative abundance were compared between RA patients and controls. Correlation analyses were conducted to evaluate the relationship between microbial abundance and clinical markers such as autoantibodies and disease activity. Microbial diversity analysis revealed no major differences between RA patients and healthy controls. However, beta diversity analysis indicated a subtle distinction in microbial composition (unweighted UniFrac distance) between the two groups (P = 0.03), hinting at a minor subset of microbiota associated with disease status. Differential abundance analysis uncovered specific taxa at various taxonomic levels, including Saccharibacteria (TM7) [O-1] (PFDR = 2.53 × 10-2), TM7 [F-1] (PFDR = 5.20 × 10-3), Microbacterium (PFDR = 3.37 × 10-4), and Stenotrophomonas (PFDR = 2.57 × 10-3). The relative abundance of ten genera correlated significantly with anti-cyclic citrullinated peptide (anti-CCP) antibody levels (PFDR < 0.05) and 11 genera were significantly associated with disease activity markers, including ESR, CRP, DAS28-ESR, and DAS-CRP (PFDR < 0.05). In particular, Saccharibacteria TM7 [G-3] and Peptostreptococcaceae [XI] [G-1] were correlated with all disease activity biomarkers. Dysbiosis in the upper respiratory mucosa is associated with RA, anti-CCP antibody levels, and disease activity.

Integrative analysis of microbiome and metabolome revealed the effect of microbial inoculant on microbial community diversity and function in rhizospheric soil under tobacco monoculture.

Over-application of chemical fertilizers and continuous cropping obstacles seriously restrict the sustainable development of tobacco production. Localized fertilization of beneficial microbes has potential advantages in achieving higher productivity, but the underlying biological mechanisms of interactions between rhizospheric microorganisms and the related metabolic cycle remain poorly characterized. Here, an integrative analysis of microbiomes with non-targeted metabolomics was performed on 30 soil samples of rhizosphere, root surrounding, and bulk soils from flue-cured tobacco under continuous and non-continuous monocropping systems. The analysis was conducted using UPLC-MS/MS platforms and high-throughput amplicon sequencing targeting the bacterial 16S rRNA gene and fungal ITS gene. The microbial inoculant consisted of Bacillus subtilis, B. velezensis, and B. licheniformis at the ratio of 1:1:1 in effective microbial counts, improved the cured leaf yield and disease resistance of tobacco, and enhanced nicotine and nitrogen contents of tobacco leaves. The bacterial taxa Rhizobium, Pseudomonas, Sphingomonadaceae, and Burkholderiaceae of the phylum Proteobacteria accumulated in high relative abundance and were identified as biomarkers following the application of the microbial inoculant. Under continuous monocropping, metabolomics demonstrated that the application of the microbial inoculant significantly affected the soil metabolite spectrum, and the differential metabolites were significantly enriched to the synthesis and degradation of nicotine (nicotinate and nicotinamide metabolism and biosynthesis of alkaloids derived from nicotinic acid). In addition, microbes were closely related to the accumulation of metabolites through correlation analysis. The interactions between plant roots and rhizospheric microorganisms provide valuable information for understanding how these beneficial microbes affect complex biological processes and the adaption capacity of plants to environments.IMPORTANCEThis study elaborated on how the microbial fertilizer significantly changed overall community structures and metabolite spectrum of rhizospheric microbes, which provide insights into the process of rhizosphere microbial remolding in response to continuous monocropping. we verified the hypothesis that the application of the microbial inoculant in continuous cropping would lead to the selection of distinct microbiota communities by establishing models to correlate biomarkers. Through correlation analysis of the microbiome and metabolome, we proved that rhizospheric microbes were closely related to the accumulation of metabolites, including the synthesis and degradation of nicotine. The interactions between plant roots and rhizospheric microorganisms provide valuable information for understanding how these beneficial microbes affect complex biological processes and the adaption capacity of plants to environments.

The description of a novel Gloeothece species (Chroococcales, Cyanobacteria) from China, based on a polyphasic approach

Cyanobacteria, with strong adaptability, occupied an important position on the earth all the time. In this study, the strain of coccoid cyanobacteria (CHAB 5847) was isolated and purified from Guizhou Province, China. The phylogenetic and taxonomic characteristics of CHAB 5847 were studied using polyphasic approach combining morphological, ecological and molecular data. Based on phylogenetic analysis of 16S rRNA gene sequence, the studied strain occupied a unique position, and clustered in Gloeothece clade. The 16S rRNA gene sequences of two clones of the studied strain shared 93.1%–98.1% similarity to other Gloeothece species, which supports well it to be a new member of Gloeothece genus. Furthermore, the unique pattern of D1-D1′, Box-B and V3 helix of the 16S–23S rRNA internal transcribed spacer (ITS) secondary structure revealed that the strain represented a novel species. These results support the establishment of a new species of Gloeothece genus with the name G. guizhouensis sp. nov.

Genetic Patterns of Oral Cavity Microbiome in Patients with Sickle Cell Disease

The Middle Eastern prevalence of sickle cell anemia, a genetic disorder that affects red blood cells, necessitates additional research. On a molecular level, we sought to identify and sort the oral microbiota of healthy individuals and those with sickle cell anemia. Furthermore, it is crucial to comprehend how changes in the genetic makeup of the oral microbiota impact the state of sickle cell anemia. Using next-generation sequencing, the 16S rRNA amplicon was examined using saliva samples from 36 individuals with sickle cell anemia and healthy individuals. These samples were obtained from sickle cell anemia patients (18 samples) and healthy control participants (controls, 18 samples). Various analyses are conducted using bioinformatic techniques to identify distinct species and their relative abundance. Streptococcus, followed by Fusobacterium nucleatum, Prevotella, and Veillonella were the most prevalent genera of bacteria in the saliva of the SCA and non-SCA individuals according to our findings. Rothia mucilaginosa, Prevotella scoposa, and Veillonella dispar species were the dominant species in both sickle cell anemia and non-sickle cell anemia subjects. Streptococcus salivarius, Actinomyces graevenitzii, Actinomyces odontolyticus, and Actinomyces georgiae spp. were the most prevalent bacterial spp. in the studied SCA cases. The sequencing of the 16S rRNA gene yielded relative abundance values that were visualized through a heatmap analysis. Alterations in the oral microflora’s constitution can significantly affect the susceptibility of sickle cell anemia patients to develop more severe health complications. Salivary diagnosis is a potential tool for predicting and preventing oral microbiome-related diseases in the future.

Increased macrolide resistance rate of Mycoplasma pneumoniae correlated with epidemic in Beijing, China in 2023

We collected respiratory specimens from 128 pediatric patients diagnosed with pneumonia in Beijing in late 2023. Mycoplasma pneumoniae was detected in 77.3% (99/128) patients, with 36.4% (4/11), 82.9% (34/41), 80.3% (61/76) in children aged less than 3 years, 3–6 years, over 7 years, respectively. Mycoplasma pneumoniae (M. pneumoniae) was characterized using P1 gene typing, MLVA typing and sequencing of domain V of the 23S rRNA gene. P1 gene type 1 (P1-1; 76.1%, 54/71) and MLVA type 4-5-7-2 (73.7%, 73/99) were predominant. MLVA identified a new genotype: 3–4–6-2. Macrolide resistance-associated mutations were detected in 100% of samples, with A2063G accounting for 99% and A2064G for 1%. The positive rate of M. pneumoniae was higher compared to previous reports, especially in children less than 3 years, suggesting a M. pneumoniae epidemic showing a younger age trend occurred in late 2023 in Beijing, China. Higher proportions of macrolide-resistant M. pneumoniae, P1-1 and 4-5-7-2 genotype M. pneumoniae indicated increased macrolide resistance rate and genotyping shift phenomenon, which might be attributable to this epidemic. Additionally, complete clinical information from 73 M. pneumoniae pneumonia inpatients were analyzed. The incidence of severe M. pneumoniae pneumonia was 56.2% (41/73). Mycoplasma pneumoniae pneumonia patients exhibited longer duration of fever, with a median value of 10.0 days (IQR, 8.0–13.0), and higher incidence of complications (74.0%, 54/73). However, in this cohort, we found that the severity of M. pneumoniae pneumonia, co-infection, or complications were not associated with M. pneumoniae P1 gene or MLVA types. Clinicians should be aware that patients infected with macrolide-resistant M. pneumoniae exhibited more severe clinical presentations.

Database size positively correlates with the loss of species-level taxonomic resolution for the 16S rRNA and other prokaryotic marker genes.

For decades, the 16S rRNA gene has been used to taxonomically classify prokaryotic species and to taxonomically profile microbial communities. However, the 16S rRNA gene has been criticized for being too conserved to differentiate between distinct species. We argue that the inability to differentiate between species is not a unique feature of the 16S rRNA gene. Rather, we observe the gradual loss of species-level resolution for other nearly-universal prokaryotic marker genes as the number of gene sequences increases in reference databases. This trend was strongly correlated with how represented a taxonomic group was in the database and indicates that, at the gene-level, the boundaries between many species might be fuzzy. Through our study, we argue that any approach that relies on a single marker to distinguish bacterial taxa is fraught even if some markers appear to be discriminative in current databases.

SDS-protein and 18S rRNA gene, and phylogeny-based identification of hydatid cysts in human and animal samples

Hydatid disease is a significant and widespread infectious disease prevalent in many countries where there is inadequate control of the adult tapeworm; Echinococcus spp, in dogs, which are the definite hosts. The disease is caused by the presence of hydatid cysts in intermediate hosts, such as humans and some farm animals. In Iraq, infected dogs are highly likely to transmit the infection to humans and some farm animals. The study aimed to identify the presence of hydatid cysts in human and animal samples. The research involved collecting thirty hydatid cysts from human livers and ovaries, as well as from animal livers and lungs. The samples were subjected to SDS-based protein detection, PCR, and gene sequencing of the 18S rRNA gene. The SDS-Coomassie-blue findings demonstrated a 100% (15/15) positive identification of the cystic protein of all specimens. The PCR results confirmed the identity of the parasite with 100% accuracy. Sequencing and phylogenetic analysis of 10 PCR products from both human and animal samples revealed close nucleotide identity to global isolates previously deposited in GeneBank. These findings indicate a high occurrence of hydatid cysts in the examined humans and animals, which have evolved or exhibit close genetic similarity to global strains.

Functional genomics and taxonomic insights into heavymetaltolerant novel bacterium Brevibacterium metallidurans sp. nov. NCCP-602T isolated from tannery effluent in Pakistan.

The strain designated NCCP-602T was isolated from tannery effluent, and displayed aerobic, gram-positive, rod-shaped cells that were characterized by oxidase negative, catalase positive, and non-motile features. The most favourable growth conditions were observed at a temperature of 30°C, pH 7.0, and NaCl concentration of 1% (w/v). It tolerated heavy metals at high concentrations of chromium (3600 ppm), copper (3300 ppm), cadmium (3000 ppm), arsenic (1200 ppm) and lead (1500 ppm). The results of phylogenetic analysis, derived from sequences of the 16S rRNA gene, indicated the position of strain NCCP-602T within genus Brevibacterium and showed that it was closely related to Brevibacterium ammoniilyticum JCM 17537T. Strain NCCP-602T formed a robust branch that was clearly separate from closely related taxa. A comparison of 16S rRNA gene sequence similarity and dDDH values between the closely related type strains and strain NCCP-602T provided additional evidence supporting the classification of strain NCCP-602T as a distinct novel genospecies. The polar lipid profile included diphosphatidylglycerol, glycolipid, phospholipids and amino lipids. MK-7 and MK-8 were found as the respiratory quinones, while anteiso-C15:0, iso-C15:0, iso-C16:0, iso-C17:0, and anteiso-C17:0 were identified as the predominant cellular fatty acids (> 10%). Considering the convergence of phylogenetic, phenotypic, chemotaxonomic, and genotypic traits, it is suggested that strain NCCP-602T be classified as a distinct species Brevibacterium metallidurans sp. nov. within genus Brevibacterium with type strain NCCP-602T (JCM 18882T = CGMCC1.62055T).

Four Novel Species of Kastovskya (Coleofasciculaceae, Cyanobacteriota) from Three Continents with a Taxonomic Revision of Symplocastrum

Studies performed in North America, Africa, and South America have led to the isolation of four new species of Kastovskya, a filamentous cyanobacterial genus that before this manuscript had only one species, Kastovskya adunca from Chile. Kastovskya nitens and K. viridissima were isolated from soils on San Nicolas Island, K. sahariensis was isolated from hypolithic habitats from the Sahara Desert in Algeria, and K. circularithylacoides was isolated from hypolithic habitats in Chile. The molecular analyses are corroborated by morphological data, morphometric analysis, and ecological and biogeographical considerations for robust polyphasic descriptions of all taxa. The peculiar transatlantic distribution of this genus bears similarity to other taxa in recently published studies and is in agreement with a hypothesis suggesting that cyanobacteria in Africa may disperse to the Americas on dust particles during windstorms. This work is unusual in that species in a single rare cyanobacterial genus with a disjunct distribution are described simultaneously from three continents. The 16S rRNA gene analyses performed for this study also revealed that another recent genus, Arizonema, is clearly a later synonym of Symplocastrum. This issue is resolved here with the collapsing of the type species Arizonema commune into Symplocastrum flechtnerae.

Microbial communities and functions are structured by vertical geochemical zones in a northern peatland

Northern peatlands are important carbon pools; however, differences in the structure and function of microbiomes inhabiting contrasting geochemical zones within these peatlands have rarely been emphasized. Using 16S rRNA gene sequencing, metagenomic profiling, and detailed geochemical analyses, we investigated the taxonomic composition and genetic potential across various geochemical zones of a typical northern peatland profile in the Changbai Mountains region (Northeastern China). Specifically, we focused on elucidating the turnover of organic carbon, sulfur (S), nitrogen (N), and methane (CH4). Three geochemical zones were identified and characterized according to porewater and solid-phase analyses: the redox interface (<10 cm), shallow peat (10–100 cm), and deep peat (>100 cm). The redox interface and upper shallow peat demonstrated a high availability of labile carbon, which decreased toward deeper peat. In deep peat, anaerobic respiration and methanogenesis were likely constrained by thermodynamics, rather than solely driven by available carbon, as the acetate concentrations reached 90 μmol·L−1. Both the microbial community composition and metabolic potentials were significantly different (p < 0.05) among the redox interface, shallow peat, and deep peat. The redox interface demonstrated a close interaction between N, S, and CH4 cycling, mainly driven by Thermodesulfovibrionia, Bradyrhizobium, and Syntrophorhabdia metagenome-assembled genomes (MAGs). The archaeal Bathyarchaeia were indicated to play a significant role in the organic carbon, N, and S cycling in shallow peat. Although constrained by anaerobic respiration and methanogenesis, deep peat exhibited a higher metabolic potential for organic carbon degradation, primarily mediated by Acidobacteriota. In terms of CH4 turnover, subsurface peat (10–20 cm) was a CH4 production hotspot, with a net turnover rate of ∼2.9 nmol·cm−3·d−1, while the acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways all potentially contributed to CH4 production. The results of this study improve our understanding of biogeochemical cycles and CH4 turnover along peatland profiles.

First Report of Streptomyces brasiliscabiei Causing Common Scab on Potato in China.

Severe typical deep-pitted lesions of Potato Common Scab (PCS) disease were observed in two locations in China, Dingxi, Gansu Province, and Shuozhou, Shaanxi Province, in 2021. Potato farms in Dingxi growing cultivar Huangxin 226 (26 hectares) exhibited a scab disease incidence of 10%, while cultivar Jinshu 15# (4 hectares) in Shuozhou showed a disease incidence of 30% (Fig. 1). During harvest, tubers displaying PCS symptoms were collected for pathogen isolation. To obtain pathogen isolates, surface-sterilized tuber tissue with scab lesions was ground in sterile water, serially diluted, and plated onto ISP5 agar medium plates (Handique et al. 2022). Five pure colonies of Streptomyces isolate were obtained, designated as ZRIMU1503, ZRIMU1502, ZRIMU1320, ZRIMU1321and ZRIMU791. Genomic DNA was extracted and sequenced using Illumina technology. Sequencing data of the 5 isolates were uploaded to NCBI GenBank and annotated (Accession numbers: JBBAYL010000000, JBBAYM010000000, JBBAYN010000000, JBBAYO010000000 and JBBAYP010000000, respectively) using the PGAP pipeline (Tatusova et al. 2016). Average Nucleotide Identity (ANI) values (97.52 %, 97.53 %,97.54 %,97.57 % and 97.52 %, respectively) indicated the identity of the five isolates to the type strain S. brasiliscabiei IBSBF 2867T. Additionally, pairwise comparisons of Digital DNA Hybridization (DDH) value (76.2%, 76.3%, 76.4%, 76.4% and 76.2% respectively) of all the Streptomyces type strains show the highest identity to S. brasiliscabiei IBSBF 2867T. Twelve housekeeping genes (acnA, atpD, dnaN, gap, gyrA, gyrB , infB, mdh, recA, rplB, rpoB, and trpB) were extracted from the genome sequence of the five isolates to construct a multi-locus sequence analysis (MLSA) tree. The evolutionary distance of the five isolates was constructed using MEGAX software (Kumar et al., 1994), along with other Streptomyces strains that are known to cause PCS. The resulting cladogram demonstrated the isolated strains clustered together with S. brasiliscabiei IBSBF 2867T (Fig.2). Koch's postulates were fulfilled by inoculating a perlite potting mix with spore suspensions of each isolate (104 CFU/ml), planting tubers (cv. Favorita), and reproducing PCS symptoms at harvest after three months. Negative control received water treatment. The plants were kept in greenhouse with 12 h of light per day and irrigated regularly. The experiment was repeated twice, once in April 2022 and again in April 2023. On harvest, all five isolates exhibited development of severe symptoms of PCS (Fig.1), while the negative controls had no lesions. The pathogen was reisolated from the lesions and confirmed to be identical to the original isolate by 16S rRNA gene sequences. To our knowledge, this is the first report of S. brasiliscabiei causing PCS in China. S. brasiliscabiei was identified as a new species to cause PCS in Brazil and was identified based on morphology, pathogenicity, and genetic features (Corrêa et al. 2021). Multiple pathogen-causing PCS has been recognized in China and a surge of disease incidence in potato fields has been reported (Handique et al. 2022; Wu et al. 2023). S. brasiliscabiei causes severe symptoms which makes potatoes unmarketable. The disease epidemiology of this pathogen needs to be investigated.

Pharmacological mechanisms of Ma Xing Shi Gan Decoction in treating influenza virus-induced pneumonia: intestinal microbiota and pulmonary glycolysis

BackgroundInfluenza virus is one of the most common pathogens that cause viral pneumonia. During pneumonia, host immune inflammation regulation involves microbiota in the intestine and glycolysis in the lung tissues. In the clinical guidelines for pneumonia treatment in China, Ma Xing Shi Gan Decoction (MXSG) is a commonly prescribed traditional Chinese medicine formulation with significant efficacy, however, it remains unclear whether its specific mechanism of action is related to the regulation of intestinal microbiota structure and lung tissue glycolysis.ObjectiveThis study aimed to investigate the mechanism of action of MXSG in an animal model of influenza virus-induced pneumonia. Specifically, we aimed to elucidate how MXSG modulates intestinal microbiota structure and lung tissue glycolysis to exert its therapeutic effects on pneumonia.MethodsWe established a mouse model of influenza virus-induced pneumoni, and treated with MXSG. We observed changes in inflammatory cytokine levels and conducted 16S rRNA gene sequencing to assess the intestinal microbiota structure and function. Additionally, targeted metabolomics was performed to analyze lung tissue glycolytic metabolites, and Western blot and enzyme-linked immunosorbent assays were performed to assess glycolysis-related enzymes, lipopolysaccharides (LPSs), HIF-1a, and macrophage surface markers. Correlation analysis was conducted between the LPS and omics results to elucidate the relationship between intestinal microbiota and lung tissue glycolysis in pneumonia animals under the intervention of Ma Xing Shi Gan Decoction.ResultsMXSG reduced the abundance of Gram-negative bacteria in the intestines, such as Proteobacteria and Helicobacter, leading to reduced LPS content in the serum and lungs. This intervention also suppressed HIF-1a activity and lung tissue glycolysis metabolism, decreased the number of M1-type macrophages, and increased the number of M2-type macrophages, effectively alleviating lung damage caused by influenza virus-induced pneumonia.ConclusionMXSG can alleviate glycolysis in lung tissue, suppress M1-type macrophage activation, promote M2-type macrophage activation, and mitigate inflammation in lung tissue. This therapeutic effect appears to be mediated by modulating gut microbiota and reducing endogenous LPS production in the intestines. This study demonstrates the therapeutic effects of MXSG on pneumonia and explores its potential mechanism, thus providing data support for the use of traditional Chinese medicine in the treatment of respiratory infectious diseases.