Search Results (3,231)

Natural saline–alkaline soils are widespread in Central Asia, yet microbial responses to salinity gradients and ionic composition remain poorly resolved. We profiled bacterial communities (16S rRNA V3–V4, Illumina MiSeq) in 20 topsoil (0–20 cm) samples from four regions of Kazakhstan spanning non-saline to highly saline conditions. Soil chemistry included pH, total mineralization (dry residue), and major ions (Na⁺, Cl⁻, SO₄²⁻, HCO₃⁻, Ca²⁺, Mg²⁺, K⁺). Alpha (Chao1, Shannon, observed ASVs) and beta diversity (Bray–Curtis; ANOSIM; PCoA) were evaluated across salinity classes. Soils were alkaline (pH 7.91–10.47) and covered a broad salinity range (256–26,312 mg/L), driven mainly by Na⁺ with chloride and/or sulfate. Alpha diversity remained stable across salinity classes, though dispersion increased under high salinity. Community composition differed significantly among classes (ANOSIM R = 0.428, p = 0.005), with partial PCoA separation and overlap, indicating gradual turnover along the salinity gradient. In contrast, fungal communities showed no significant response to salinity, with stable alpha and beta diversity across all samples and consistent dominance of Ascomycota. Communities were dominated by Actinomycetota (formerly Actinobacteriota), Bacteroidota, and Pseudomonadota (formerly Proteobacteria). Bacteroidota increased in highly saline soils (FDR q = 0.036), whereas Acidobacteriota decreased (FDR q = 0.052). Thermodesulfobacteriota (formerly Desulfobacterota) correlated positively with sulfate, and Cyanobacteriota negatively with chloride. Overall, Kazakhstan’s saline–alkaline soils show stable bacterial alpha diversity but moderate, ion-linked compositional shifts with enrichment of halotolerant taxa. Full article

Tailings remediation alleviates ecosystem degradation and protects species. To conserve terrestrial biodiversity and address sustainability challenges while achieving economic growth, numerous researchers have devoted efforts to monitoring ecological functions and optimizing community structures. This study investigates the microbial characteristics and functional diversity across ecological succession stages of tailings. Selecting three typical restoration stages, including biological crust, moss, and grassland stages, we adopt 16S rRNA and ITS gene amplification, Illumina high-throughput sequencing, spectroscopy, and network correlation analysis to explore the responses of soil multifunctionality index, microbial communities, and carbon metabolism during tailings restoration. The experimental results indicate that the functional diversity index increases with ecological succession and is significantly correlated with the bacterial genera Rubrobacter and Arenimicrobium, whereas no significant correlation is observed with dominant fungi. The network interactions among bacterial communities are gradually strengthened along the succession process. In terms of carbon metabolic functions, the relative abundances of galactose, starch, and sucrose metabolism pathways increase obviously with restoration progression, while inositol phosphate metabolism, peroxisome metabolism, retinol metabolism, glyoxylate and dicarboxylate metabolism, and xenobiotics metabolism exhibit no significant variations. These findings provide novel empirical evidence for explaining microbe-mediated ecological succession in tailing ecosystems and highlight the necessity of multi-perspective analysis for ecological restoration. Policy and practical implications emphasize that the application of specific microorganisms and their interspecific interactions to promote iron tailings ecological restoration should fully consider the spatiotemporal heterogeneity of tailings areas. This study deepens the understanding of differential microbial responses at different tailings restoration stages and provides actionable insights for balancing mining economic development and terrestrial ecosystem conservation. Full article

The white rhinoceros (Ceratotherium simum) offers a unique model for investigating the genomic consequences of extreme demographic bottlenecks. However, the fragmented southern white rhinoceros genome assembly has limited chromosome-scale structural and evolutionary comparisons with the functionally extinct northern subspecies. Here, we report a chromosome-scale genome assembly for the southern white rhinoceros by integrating Oxford Nanopore Technology long-read sequencing, Illumina short-read polishing and high-throughput chromosome conformation capture (Hi-C) scaffolding. The final assembly spans 2.48 Gb and achieves a contig N50 of 42.06 Mb, representing a 452-fold improvement in contiguity over the previous assembly. In total, 2.46 Gb of sequence was anchored to 40 autosomes plus the X and Y chromosomes. Genome annotation identified 1.13 Gb of repetitive elements (45.7% of the assembly), 22,593 protein-coding genes, and 100.68 Mb of segmental duplications. Inspection of the major histocompatibility complex class II gene region further supported the local assembly and annotation reliability, revealing conserved gene composition and order between the southern and northern white rhinoceroses. Whole-genome comparison with the northern white rhinoceros assembly indicated extensive chromosome-scale synteny, along with localized structural variants between the two subspecies, including 111 inversions spanning 33.48 Mb and 497 translocations spanning 36.48 Mb. Furthermore, coalescent demographic reconstruction indicated asynchronous Pleistocene population dynamics for southern and northern white rhinoceroses, reflecting divergent responses to historical climate oscillations. Both subspecies also exhibit lower recent effective population sizes than estimated Pleistocene ancestral levels, underscoring persistent conservation concern. This assembly provides a useful resource for evaluating the genomic consequences of historical bottlenecks, informing future genomic-rescue plans, and strengthening the comparative framework for rhinoceros conservation and evolutionary genomics. Full article

Background/Objectives: Obesity remains a global health concern, and personalized prevention strategies that consider genetic predispositions can enhance existing strategies. Research suggests that variation in circadian rhythm-related genes, or clock genes, may influence obesity risk, in part through effects on dietary behaviour. However, associations between single-nucleotide polymorphisms (SNPs) in clock genes and dietary outcomes remain understudied, particularly in children. Therefore, we investigated cross-sectional associations between clock gene SNPs and dietary outcomes using baseline data from 226 adults (138 females, 88 males) aged 26–50 y and 168 children (90 females, 78 males) aged 2–6 y from the Guelph Family Health Study. Methods: DNA was extracted from saliva and genotyped using the Illumina Global Diversity Array, and dietary intake was assessed using the Automated Self-Administered 24 h Dietary Assessment Tool. Nine SNPs representing 8 clock genes were selected based on prior associations with dietary and obesity-related outcomes. Generalized Estimating Equations were used to test associations, adjusted for multiple comparisons with the Benjamini–Hochberg false discovery rate (FDR) procedure. Results: Ten nominal associations were identified (p < 0.05), and 2 remained significant after FDR correction (P_adj < 0.05); among children, rs2314339-T (NR1D1) was associated with a lower percentage of energy from protein (β = −2.4%, P_adj = 0.003) and rs11605924-A (CRY2) with higher energy intake (β = 118.0 kcal, P_adj = 0.044). Conclusions: Findings suggest that clock gene SNPs may influence dietary habits from early childhood. Future longitudinal and functional studies are needed to clarify whether these variants can inform precision nutrition strategies for obesity prevention. Full article

Corydalis ophiocarpa is a medicinally valuable plant, noted for its abundant alkaloid content. Despite its significance, the mitochondrial (mt) genome of this plant has not been characterized, which impedes both the phylogenetic understanding within the Corydalis genus and the comprehension of its full genetic potential. In this research, we successfully assembled the complete mitogenome of C. ophiocarpa by employing a hybrid method that integrates Oxford Nanopore long reads with Illumina short reads. The assembled genome forms a circular structure of 600,064 bp, with a GC content of 46.49%, and includes 63 genes, comprising 40 unique protein-coding genes (PCGs), 20 tRNAs, and three rRNAs. Through assembly and coverage analysis, we identified a 6383 bp forward repeat associated with a contig having approximately double the depth, indicating a repeat-mediated multipartite structure where the main circle may coexist with two smaller subgenomic forms. We discovered 775 C-to-U RNA editing sites across the 40 PCGs, with 95.4% being non-synonymous and favoring hydrophobic amino acid substitutions, particularly in Complex I subunits. Furthermore, we identified sixteen mt plastid DNA fragments constituting 2.43% of the mitogenome, a proportion more than double that found in the closely related C. saxicola. Phylogenetic analysis confirms that C. ophiocarpa is most closely related to C. saxicola, with C. pauciovulata as another close relative. This study presents the first complete mitogenome of C. ophiocarpa, providing a genomic basis for investigating the relationships between mt genome structure, post-transcriptional regulation, and specialized metabolism in the Corydalis genus. Full article

Background/Objectives: Melophagus ovinus is an economically important ectoparasite of small ruminants with a broad global distribution. Although mitochondrial genomes are widely used in population genetic studies, the D-loop region of M. ovinus remains poorly characterized because its high AT content and repetitive structure complicate amplification, assembly, and sequencing. Methods: We sequenced the mitochondrial genome of M. ovinus collected from Qinghai using an integrative approach combining Illumina paired-end sequencing, targeted PCR amplification, and Nanopore long-read sequencing. Comparative genomic analysis was performed against published mitogenomes from Gansu (MH024396) and Xinjiang (NC_037368). Results: The Qinghai mitochondrial genome contained the typical 37 mitochondrial genes within a 14,728 bp conserved region. Comparative analysis revealed exceptionally high conservation (>99.6% sequence identity) among Qinghai, Gansu, and Xinjiang isolates outside the D-loop region. Notably, the D-loop exhibited length polymorphism, with different assembly strategies or samples yielding lengths ranging from 317 bp to 2385 bp. Targeted long-read sequencing of ten individuals identified a predominant D-loop variant of approximately 844 bp in nine samples and a markedly shorter variant of approximately 164 bp in one sample. The short variant was characterized by extensive deletions and a novel 45 bp insertion. Support for this variant was obtained from independent Illumina DNA-seq, RNA-seq, Nanopore sequencing, and de novo assembly analyses. Conclusions: This study provides preliminary evidence for D-loop structural heterogeneity in M. ovinus, suggesting remarkable length polymorphism and complex indel patterns that require further validation. These findings significantly expand the genomic resources available for this important veterinary parasite and establish a foundation for future population genetic and evolutionary studies. Full article

Background: Homologous recombination deficiency (HRD) is emerging as a clinically relevant biomarker across diverse tumor types, in addition to ovarian cancer. In this study, we evaluated the genomic instability score (GIS) across multiple tumor types using the TruSight Oncology 500 HRD assay, which incorporates the Myriad Genetics GIS algorithm, a widely used reference standard for HRD assessment. Methods: A total of 162 tumor samples (17 ovarian cancers and 145 non-ovarian tumors) underwent next-generation sequencing using the TruSight Oncology 500 HRD assay. Results: A total of 14 tumors were classified as GIS-High, defined as a GIS score ≥42, representing 8.6% of all cases. Among ovarian cancers, 7 out of 17 cases (41.2%) met the GIS-High threshold. Among non-ovarian tumors, seven GIS-High tumors were identified, accounting for 4.8% of cases (7/145). GIS-High cases occurred in breast (n = 4), lung (n = 2), and hepatobiliary tract (n = 1) cancers. GIS scores showed significant associations with BRCA1/2 and TP53 mutational status. In contrast, alterations in HRD-related genes other than BRCA1/2 did not show significant associations with GIS score. Conclusions: GIS-High tumors were identified in a small subset of non-ovarian cancers. These findings support further investigation of GIS as an exploratory biomarker of HRD-like genomic scarring beyond ovarian cancer, but its predictive and therapeutic relevance in non-ovarian tumors requires additional validation. Full article

Biological soil crusts (BSCs) play key roles in arid, semi-arid regions and ecological marginal habitats. This study focused on four types of sand-fixing plantations established in 1990 in alpine sandy land (Salix psammophila, SL; Caragana korshinskii, NT; Salix cheilophila, WL; Populus simonii, XYY). Soil samples were collected from bare sand, algae crusts, and moss crusts. Soil particle size distribution, physicochemical properties, and enzyme activity were determined. Then bacterial communities were analyzed using high-throughput (Illumina) sequencing and the correlations among these three factors were examined. The results showed that: (1) From bare sand to algae and moss crusts, the content of fine particles (clay + silt) gradually increased. (2) Soil water content (SWC), nutrients and enzyme activities increased progressively. (3) In the study area, the dominant bacterial phyla of BSCs included Pseudomonadota, Cyanobacteria, Actinobacteriota and Vibrionota. Principal Coordinates Analysis (PCoA) and Analysis of Similarities (ANOSIM) results showed that BSCs drive the differentiation of bacterial communities during succession, while forest stands influence their spatial distribution. (4) Spearman’s correlation and redundancy analysis (RDA) showed that available phosphorus (AP), alkaline hydrolyzable nitrogen (AN), soil organic matter (SOM), catalase (CAT), pH, soil water content (SWC), and alkaline phosphatase (ALP) are key physicochemical factors shaping the bacterial community structure of BSCs. Mantel’s test confirmed that these variables mediated BSCs’ bacterial community structure. This study elucidates the mechanisms underlying ecological restoration via BSCs and provides a theoretical basis for future restoration efforts in alpine sandy land. Full article

Background/Objectives: Early-life environment may influence long-term neurodevelopment through epigenetic regulation. Serotonergic and glutamatergic pathways are central to brain development and have been implicated in DNA methylation changes following prenatal adversity. In this study, we examined whether preterm birth (PTB) in birthweight-discordant twins is associated with differential DNA methylation in the serotonin receptor signaling pathway and the glutamatergic synapse pathway in adult twins. Methods: Genome-wide DNA methylation data were obtained from whole blood samples of 288 individuals (144 monozygotic birthweight-discordant twin pairs), including a younger cohort (140 individuals; mean age 33 years) and an older cohort (148 individuals; mean age 63 years). DNA methylation was measured using the Illumina HumanMethylation450 BeadChip. Linear models were fitted for association testing, adjusting for leukocyte composition and twin pair correlation. Pathway-level differential methylation was assessed using Rotation Gene Set Testing. Results: In the glutamatergic synapse pathway, no consistent directional enrichment of hypo- or hypermethylation was observed. However, gene-level analyses identified consistent hypomethylation of GRIA2 and GRIA4 across cohorts. In the serotonin receptor signaling pathway, the young cohort exhibited a mixed methylation pattern, whereas the old cohort showed significant enrichment of hypermethylation. At the gene level, HTR1A was hypomethylated in the young cohort but hypermethylated in the old cohort, indicating a cohort-dependent effect in the methylation patterns. Conclusions: These findings suggest that PTB is associated with long-term epigenetic variation in neurodevelopmentally relevant pathways, as reflected in blood cells. The results further indicate distinct methylation architectures across pathways, with more consistent pathway-level signals in the serotonergic system and more localized gene-level effects in the glutamatergic pathway. Full article

High-throughput sequencing is becoming the method of choice for plant diagnostics. It allows the detection of known and novel viruses and viroids, even in co-infection, without preliminary knowledge of the target. However, this method has its own limitations when compared to real-time PCR or ELISA. Laboratories that implement this type of technologies in-house must ensure that the performance criteria meet the requirements associated with their diagnostic activity. In this study, we present a workflow for in-house plant viruses and viroid detection, based on total RNA extraction, ribodepletion, Illumina sequencing and bioinformatics analyses. Performance criteria such as analytical sensitivity, analytical specificity, selectivity, repeatability, reproducibility and robustness were evaluated on the tomato brown rugose fruit virus (RNA genome), the tomato leaf curl New Delhi virus (DNA genome), and the pepper chat fruit viroid (RNA genome). The performance levels obtained meet the requirements for virus and viroid detection in symptomatic plant samples. Full article

Background: Persistent high-risk human papillomavirus (hrHPV) infection causes over 99% of cervical precancers and cancers worldwide, with HPV genotype 16 (HPV16) responsible for 50% of the cases. Latvia ranks among the top EU countries for cervical cancer incidence and mortality. In the general Latvian population, 4.2% of women are hrHPV-infected, mostly with HPV16. However, information on the circulating HPV16 isolates is missing. Objectives: To study the genomic variability of the Latvian HPV16 isolates, compare them with HPV16 in Europe and across the globe, reveal features associated with the severity of cervical disease and uncover eventual sequence changes due to the national HPV vaccination. Methods: DNA was extracted from the formalin-fixed paraffin-embedded cervical tissues of women diagnosed with cervical intraepithelial neoplasia (CIN) stages I-III and squamous cell carcinoma (SCC) grades 1–3, collected between 2012 and 2024. Samples positive for HPV16 were subjected to whole genome sequencing (WGS) on the Illumina platform (n = 16) or Sanger sequencing of the E6/E7 coding region (n = 31). A consensus HPV16 sequence was generated, and single nucleotide polymorphisms (SNPs) and eventual amino acid substitutions (AAS) were analysed. Results: Complete genomes of 16 HPV16 variants were reconstructed, with 13 related to the European sublineage A1 and 3 to the sublineage A2 references. Sequences showed high conservation; still 93 non-redundant variants were identified. The highest variability was observed for the capsid protein L2, and the lowest, for oncoprotein E7. The prevalence of SNPs and AAS in the Latvian HPV16 variants, specifically in capsid protein L1, did not increase with time, showing no effect of HPV vaccination. Associations between HPV16 sequence features and severity of cervical disease were limited to AAS E6:L90V, which was significantly more common in SCC grade 2/3 than in CINII/III cases (p = 0.015). Conclusions: Highly conserved HPV16 genomes circulating in Latvia harbour a series of unique as well as common nonsynonymous SNPs with respective AAS, with one, AAS E6:L90V, associating with disease severity. No HPV vaccine escape variants were detected. Deciphering complete genomes of HPV16 from CIN and SCC cases in Latvia informs public authorities performing HPV vaccination and is useful for the management of HPV-associated cervical diseases. Full article

Understanding biological communities is essential for elucidating ecosystem structure and function. Metabarcoding based on ribosomal RNA (rRNA) genes, particularly 16S and 23S, is widely used to characterise bacterial and microalgal communities. However, analysing high-throughput sequencing data generated by platforms such as the Illumina MiSeq remains challenging due to fragmented bioinformatics tools, complex parameterisation, and limited accessibility for non-specialist users. In this study, a comprehensive and user-friendly bioinformatics pipeline is proposed for the analysis of 16S and 23S paired-end metabarcoding data. The workflow integrates all critical processing steps, including read merging, primer and adapter trimming, quality filtering, dereplication, chimaera removal, and clustering into Operational Taxonomic Units (OTUs). Taxonomic assignment is performed using curated reference databases, namely EZBioCloud for bacterial communities and µgreen for microalgae. The pipeline was developed in Python 3.11 and incorporates validated tools such as VSEARCH and Cutadapt, ensuring robustness and computational efficiency. Additionally, modules for alpha and beta diversity analysis are included to support comprehensive ecological interpretation. The main novelty of this work lies in providing a unified, GUI-based framework that enables the standardised processing of dual-marker (16S/23S) metabarcoding data within a single environment. In its current implementation, SOMBA supports the analysis of each marker through separate but harmonised workflows, ensuring consistency in parameterisation, processing steps, and output structure. This approach provides an accessible and standardised solution that bridges the gap between raw sequencing data and reliable biological insights, supporting applications in environmental microbiology and biotechnology. Full article

Atypical Salmonella enterica strains that evade conventional detection pose significant challenges to food safety surveillance. A hydrogen sulfide (H₂S)-negative and serologically untypable S. enterica strain (SF1060) was detected by qPCR from cooked farmed mussels in Galicia, Spain, and characterized using phenotypic and genomic approaches. Despite typical biochemical profiles, SF1060 failed to produce black colonies on Xylose Lysine Deoxycholate (XLD) agar and lacked detectable somatic antigens by conventional serotyping. Hybrid genome assembly using nanopore and illumina sequencing yielded a closed chromosome and five plasmids. In silico analyses identified the strain as S. Senftenberg ST14. Comparative genomics revealed a chromosomal inversion at the rfb operon (encoding enzymes needed to synthesize deoxysugars and O antigens) mediated by IS5-family transposase ISEc68, which truncated the rfbD gene and separated the remaining rfb genes at rfbD, disrupting O-antigen biosynthesis, explaining the inconclusive phenotypic serotyping results. The phs operon responsible for H₂S production lacked premature stop codons, suggesting the H₂S-negative phenotype may result from an alternative mechanism. This study demonstrates how whole-genome sequencing resolves identification of atypical strains that fail culture-based detection and emphasizes the critical need for molecular surveillance methods in seafood safety programs, particularly in regions where atypical S. enterica variants may be endemic. Full article

Pathogenicity islands (PAIs) are regions of bacterial genomes that harbor genes encoding virulence factors. Identifying molecules that enhance pathogenicity is crucial for understanding the mechanisms pathogens employ to cause disease and their evolution. Corynebacterium pseudotuberculosis (C. pseudotuberculosis) is a pathogenic microorganism that causes caseous lymphadenitis (CLA) in sheep and goats. Despite its prevalence in Mexico, its genetic material has not been analyzed for virulence factors acquired through horizontal gene transfer. Therefore, the aim of this study was to characterize the complete genomes of Mexican C. pseudotuberculosis strains and identify virulence-related genes harbored with PAIs. Seventeen strains of C.pseudotuberculosis biovar ovis isolated from Mexico were whole-genome sequenced using illumina technology, assembled de novo with SPAdes, and annotated using Prokka. PAIs were predicted with GIPSy based on genomic signatures associated with horizontal gene transfer, including G + C deviation, codon usage, virulence factors, transposases, and tRNA-flanking regions. Positive selection was assessed using POTION v1.2 by identifying orthologous groups enriched in non-synonymous substitutions. This represents the first comprehensive PAI analysis of Mexican C. pseudotuberculosis strains, identifying 14 putative pathogenicity islands harboring 51 virulence-associated genes. Additionally, positive selection analysis identified five coding sequences, including radA and rpiB, that are undergoing adaptive evolutionary changes. These findings elucidate the pathogenic mechanisms and genomic plasticity of Mexican C. pseudotuberculosis strains. They also highlight novel genetic targets for vaccine and therapeutic development against CLA. Full article

Under a One Health framework, viruses of veterinary and zoonotic importance pose significant threats to animal and human health, food security, and livelihoods, particularly in regions with intense human–animal interactions. In West Africa, despite recent advances in surveillance programs, important gaps remain in understanding viral diversity and cross-species transmission at wildlife–livestock interfaces. We conducted metagenomic surveillance to characterize viruses circulating across livestock, domestic animals, and wildlife in rural Ghana in 165 animals sampled across five regions. Viral RNA from serum and tissue samples was sequenced with the Illumina platform, and genomes were de novo assembled with MEGAHIT. Phylogenetic relationships were reconstructed using Bayesian approaches. We report the first genomic sequences of porcine parvovirus 3, canine parvovirus, rotavirus A genotype R16, and bovine hepacivirus subtype B from Ghana in over a decade. Phylogenetic analyses revealed intercontinental linkages between Africa and Europe for parvoviruses, persistence of hepacivirus lineages, and evidence of cross-species transmission for rotavirus. Notably, detection in apparently healthy animals highlights underrecognized circulation, gaps in vaccination effectiveness, trade-related biosecurity vulnerabilities, and the role of wildlife in viral maintenance and transmission. Our findings reveal dynamic viral diversity and connectivity across animal populations and ecological interfaces, emphasizing the fluid and interconnected nature of pathogen circulation within One Health systems. By integrating metagenomics and phylogenetics, this study provides a scalable framework for enhancing surveillance capacity, enabling the early detection of emerging threats and informing targeted strategies to mitigate zoonotic and economically important viral diseases in West Africa. Full article