Search Results (434)

Background/Objectives: The Y chromosome plays a crucial role in male fertility, sex determination, and spermatogenesis, yet it remains poorly characterized in Mediterranean river buffalo (Bubalus bubalis, 2n = 50) because of its high repeat content, extensive heterochromatin, and complex palindromic structures. Although a chromosome-level Y assembly is available for swamp buffalo (2n = 48), no equivalent reference exists for the river type. Methods: To address this gap, Y chromosomes from 10 Mediterranean buffalo bulls were isolated by laser microdissection following peripheral blood culture and whole-chromosome amplification. Probe specificity was verified by FISH, and amplified Y chromosomes were sequenced using Illumina NovaSeq 6000 (Illumina, San Diego, CA, USA). Sequencing data were assembled and analysed through de novo assembly, repeat identification, sequence alignment, and variant detection. Comparative analyses included alignment to the swamp buffalo Y chromosome and annotation of Y-linked genes using the Bos taurus reference genome. Results: FISH confirmed the specificity of the isolated material, showing strong signals on the Y chromosome and on X/Y PAR and heterochromatic regions. Sequencing generated over 240 million paired-end reads, and de novo assembly produced 566,815 contigs. Repeat analysis identified 3.91% repetitive elements, mainly SINEs, while variant calling detected more than 23,000 variants. Comparative analyses mapped several contigs to the swamp buffalo Y chromosome and Y-linked genes. Annotation against the B. taurus genome identified 26 unique genes, including homologs shared with the X chromosome, and revealed MSY gene duplications, including 10 copies of TSPY and 3 of HSFY. Conclusions: These findings show that laser microdissection with NGS enables effective access to the buffalo Y chromosome, representing a milestone in the characterization of the river type genome, and providing a basis for studies on buffalo male fertility and breeding programs. Full article

Bonellia viridis, an echiuran polychaete that inhabits infralittoral rocky habitats around the Atlantic, Mediterranean, and Southeastern Pacific coastlines, exhibits environmentally mediated sexual dimorphism: planktonic larvae develop into dwarf males after exposure to bonellin, a green pigment produced by adult females. Bonellin is a chlorin with a structure consistent with derivation from uroporphyrinogen III, the last universal precursor of all known tetrapyrroles, yet its biosynthesis remains unknown. Here, the de novo genome assembly for a single adult female specimen of B. viridis isolated from Okinawa has been generated (via Illumina sequencing) and found to comprise 429.95 Mb across 95,859 contigs, with an N50 of 6505 bp, recovering 83.3% of near-universal metazoan BUSCO orthologs. Homologs of all canonical enzymes of the heme biosynthetic pathway (termed hem genes) were identified across the genome. The genomic resources establish a foundation for research into the biochemical basis of pigment production, chemically mediated sex determination, and the distinct biology of B. viridis. Full article

Bioprospecting for extremozymes from unique ecological niches is crucial for developing robust biocatalysts for green chemistry. Here, we report the de novo hybrid genome assembly of Penicillium crustosum CTM10622, isolated from the humid montane forest of El Feïdja National Park, Tunisia. Using Illumina NextSeq™ 500 and Nanopore PromethION 2 Solo, a highly contiguous 31.38 Mb assembly (N50 = 1.94 Mb; 98.3% BUSCOs) was achieved. This robust genomic foundation enabled the identification of an extensive hydrolase repertoire, leading to the discovery of a novel alkaline serine lipase, PCLIP, subsequently heterologously expressed in Pichia pastoris. Recombinant rPCLIP exhibited a high specific activity (15,000 U/mg at pH 10, 65 °C) and exceptional thermostability, with half-lives of 14 and 8 h at 80 and 90 °C, respectively. The enzyme’s identity as a serine lipase was confirmed by its complete inhibition by Orlistat or tetrahydrolipstatin (THL) (51 µM), PMSF (5 mM), and diisopropylfluorophosphate (DIFP) (2 mM). To determine its substrate specificity, advanced computational approaches, including convolutional neural network-based docking and explicitly solvated molecular dynamics, were employed to compare rPCLIP with its homologue PCrL, a recombinant serine alkaline lipase from Penicillium crustosum Thom P22. While rPCLIP showed optimal experimental activity toward short-chain glyceryl tributyrate, simulations revealed that long-chain trioctanoin acts as a ‘thermodynamic trap’ due to over-stabilization. Conversely, the rigid rPCrL favors tricaprylin, driven by a ‘hydrophobic engine’ effect where the solvated environment forces chain burial with minimal entropic penalty. The findings demonstrate that rPCLIP specificity is driven by a delicate interplay of geometric complementarity, Van der Waals enthalpy, and conformational entropy. 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

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

A novel quantum algorithm for biological sequence alignment is presented and analyzed. The large volumes of data generated through genome sequencing, de novo assembly, resequencing, and transcriptome sequencing at the DNA and RNA levels foreshadow the growing demand for higher computational power and more sophisticated alignment methodologies. The rapid advancement of modern sequencing technologies in genomics has motivated the reconsideration of existing approaches for the design and implementation of alignment protocols. Emerging quantum computing accelerators may provide transformative solutions in this domain as quantum hardware progressively reaches higher levels of gate-operation maturity. This work proposes a computer-vision-based approach that exploits the unique properties of quantum entanglement within a dot-matrix representation to address the increasing demand for efficient processing of biological data. A quantum-accelerated protocol is developed and evaluated using the Qiskit software framework of IBM. Runtime experiments support the potential of the proposed methodology to provide advantageous sequence-alignment performance in terms of accuracy, completeness, and computational complexity. The system is evaluated under multiple operational conditions and demonstrates promising performance advantages. Full article

Abortion in cattle entails substantial economic loss, and rapid identification of abortigenic pathogens is critical for timely on-farm response and reduction in human exposure risk. In 2024, two Holstein cows from a small farm in Inner Mongolia aborted in close succession without an obvious cause. Vulvar swabs from both cows, one afterbirth sample, and whole blood from one aborted fetus were collected. Shotgun metagenomic sequencing was performed, followed by host-read removal, taxonomic profiling with Kraken2, de novo assembly of Brucella-aligned reads, and whole-genome comparison. Serological tests, Gram-stained smears, and Brucella genus- and species-specific qPCR assays were used as orthogonal verification. Putative resistance and virulence determinants were screened against CARD and VFDB. Brucella reads were detected in all samples, with the highest relative abundance in the 138-afterbirth (96%). qPCR assays detected Brucella DNA and B. abortus-specific signals in all four samples. A draft Brucella genome was assembled from the 138-afterbirth sample and was phylogenetically placed within B. abortus, showing relatedness to previously circulating Chinese lineages. Cows 138 and 198 were RBT-positive with SAT titres of 1:100 (++). No acquired Brucella resistance genes were identified in CARD. Within 72 h of sample receipt, B. abortus was reported to the farm and local authorities and emergency biosecurity measures were implemented. This field investigation shows that metagenomic sequencing, when combined with conventional serology, microscopy, and targeted qPCR, can support rapid etiological investigation when culture is delayed, hazardous, or biosafety level 3 facilities are unavailable. Full article

The genus Cymbopogon comprises neocosmopolitan grasses widely used as medicinal plants and in the perfume, pharmaceutical and herbal product industries. Despite their economic relevance, these species are still considered orphan crops, with limited phytotechnical, genomic and evolutionary studies within the Poaceae family. In this study, we investigated the evolutionary relationships of Cymbopogon flexuosus and Cymbopogon winterianus, with a focus on differences in gene expression associated with the biosynthesis of secondary metabolites. De novo transcriptome assembly yielded 25,576 transcripts in C. flexuosus and 42,250 in C. winterianus. A total of 5318 and 8631 more informative differentially expressed transcripts (DETs) were identified in each mapping, among which 76 and 94 were associated with secondary metabolism pathways. When mapping the libraries against related species, the highest percentages of mapped reads per transcriptome and per gene (depth) were observed in Andropogon gerardi, Sorghum bicolor, Saccharum officinarum, Miscanthus sinensis, Miscanthus lutarioriparius and Zea mays. These results indicate A. gerardi, S. bicolor and Z. mays as the most promising genomic models for future studies within the genus Cymbopogon. Comparison of the expression of transcripts that are homologous to the precursor enzymes of terpenoids, phenylpropanoids, flavonoids and other secondary metabolites revealed a complex and non-linear interaction between the metabolic pathways in each species and it was not possible to predict the predominance of greater expression of a class of metabolites on a given species. Full article

Bats are recognized reservoirs for a vast array of viral diversity, including members of the Hepadnaviridae family. Within a One Health framework, genomic surveillance of these animals is fundamental to understanding viral diversity and the potential risks of zoonotic spillover in high-density human population areas. This study describes the detection of a bat hepadnavirus through agnostic viral metagenomics in samples from passive surveillance collected in urban and peri-urban areas in Brazil. Sequencing was performed using the Oxford Nanopore Technologies (MinION) platform, and the bioinformatics pipeline involved de novo assembly and taxonomic identification against viral databases. We identified several contigs with similarity to the Tent-making bat hepatitis B virus (TBHBV) in a single liver sample. The largest contig (3182 bp) represents the complete genome, exhibiting a nucleotide identity of 80.93% with the original reference isolate. Our findings document the circulation of this viral lineage in a new epidemiological setting (the Brazilian urban interface), underscoring the importance of continuous surveillance to monitor the evolution and geographic distribution of bat orthohepadnaviruses and their relevance to public health. Full article

Quercus oxyphylla (E. H. Wilson) Hand.-Mazz. is a threatened evergreen subalpine tree species with fragmented habitats native to China. Here, we present a de novo chromosome-level genome assembly of this oak species by integrating PacBio long-read high-fidelity (HiFi) sequencing and Hi-C mapping technologies. The assembled genome size of Q. oxyphylla in this study is 824.15 megabases (Mb) in length with 12 putative chromosomes. Genome annotation of this oak species identified 514.09 Mb of repeat sequences, 53,730 protein-coding genes and 1048 non-coding RNA sequences. Genomic analyses of whole-genome duplication (WGD) and long terminal repeat retrotransposon (LTR-RT) insertion events in Q. oxyphylla revealed no species-specific WGD and recent accumulation of LTR-RTs in the genome within the last seven million years. A phylogenomic analysis with eight oak representatives confirmed the framework phylogeny of genus Quercus and indicated that Q. oxyphylla possibly split with the ancestor of Cerris oaks about 20.4 million years ago. We identified 2074 expanded and 903 contracted gene families across the genome assembly of Q. oxyphylla, while the significantly expanded gene families had notable disease resistance-related genes that were mainly enriched in plant–pathogen interaction pathways. The high-quality genome assembly of Q. oxyphylla generated in this study provides a valuable genome resource for the genetic conservation and management of Q. oxyphylla, and may facilitate our understanding of genome evolution and species adaptation of the oak lineage. Full article

Background: Elaeagnus oxycarpa Schltdl. (Elaeagnaceae) is a vital sand-fixing tree species in the arid, semi-arid, and desert regions of China, holding significant ecological and economic value. However, its chloroplast (cp) genome has not been previously characterized. Results: In this study, we sequenced the complete cp genome of Elaeagnus oxycarpa using Illumina high-throughput sequencing technology. We performed de novo assembly, annotation, and comparative genomic and phylogenetic analyses with six other Elaeagnaceae species. The results revealed a typical quadripartite structure for the E. oxycarpa cp genome, with a total length of 150,567 bp and a GC content of 36.90%. Annotation identified 132 genes, comprising 86 protein-coding genes (PCGs), 38 tRNA genes, and 8 rRNA genes. Codon usage bias analysis indicated a preference for A/U endings, with leucine codons being the most frequent (9.5%). Additionally, 77 simple sequence repeat (SSR) loci were detected, predominantly mononucleotide repeats (71.4%). Comparative genomic analysis demonstrated high sequence conservation among the seven Elaeagnus species, with nucleotide variations primarily concentrated in non-coding regions and intergenic spacers of genes such as rps16, ycf1, and trnC-GCA. These variable regions and SSR loci represent valuable molecular markers for future population genetics and species identification studies on Elaeagnus. Phylogenetic analysis strongly supported the notion that E. oxycarpa and Elaeagnus angustifolia form a sister clade, indicating their close genetic relationship. Conclusions: Our findings provide crucial genomic resources and a theoretical foundation for the species identification and elucidation of the evolutionary history of Elaeagnaceae. Full article

‘Qing Zhou Mi’ (QZM) is a typical representative landrace of the late-ripening, high-resistance, and small-fruited peaches found in northern China. However, its genetic information has not been systematically analyzed. In this study, we sequenced and de novo assembled the QZM genome. The chromosome-level genome was 252.39 Mb in size, with a contig N50 of 24.35 Mb. Comparative genomic analysis found a total of 9.24 Mb unique fragments and 418 genes in the QZM genome, most of which were associated with resistance. Compared with the genomes of some early maturing peach accessions, the differentiation ability of the ACC oxidase and ethylene receptor gene families related to ethylene synthesis and transport in QZM was significantly weakened. In the genome-wide association study, we identified PpNAC1 as a major gene regulating the late-ripening trait of QZM. In addition, we discovered a novel locus associated with fruit weight and focused on a candidate gene in its regulation, PpLOB33. The findings of this study can serve as a foundation for further research on the genetic basis underlying the core traits of QZM, providing precise targets for molecular breeding. Full article

Background: Genetic stability of live-attenuated infectious laryngotracheitis virus (ILTV) vaccines is essential for consistent efficacy and safety; however, marker-based assessments targeting partial genes are often insufficient given the virus’s large, structurally complex genome. The ILTV genome contains long internal inverted repeats (IRs) that can give rise to genomic isomers, complicating short-read assembly and accurate resolution of genome structure. Methods: To overcome these limitations, we used a hybrid whole-genome sequencing (WGS) strategy, combining Oxford Nanopore Technologies (ONT) long reads to improve assembly contiguity with Illumina short reads for high-accuracy polishing at the single-nucleotide level. Using this approach, we generated complete de novo genome assemblies for the commercial Serva and Salsbury #146 vaccine strains. Results: The assemblies showed high sequence concordance with targeted regions validated by Sanger sequencing. Whole-genome analysis further enabled detection and independent validation of a structural inversion in the unique short (US) region of the Salsbury strain, consistent with herpesvirus genome isomerization. To enable phylogenetic inference despite structural variability, we performed a pangenome-based analysis to define a conserved core-genome dataset that robustly resolved vaccine-associated lineages, separating Serva- and Salsbury-derived strains. Conclusions: Collectively, these findings show that a hybrid WGS workflow can generate high-confidence genome assemblies for the specific commercial ILTV vaccine vials analyzed and can support QC-relevant detection of major structural variations. Because this study is cross-sectional (two strains; single lot/vial per strain), it cannot distinguish potential biological lot-to-lot variation from methodological differences, and a comprehensive genetic stability evaluation will require applying this workflow across defined passage levels and/or multiple production lots. Full article

In this study, we comparatively assessed short-read (Illumina), long-read (Oxford Nanopore Technologies, ONT), and hybrid (Illumina + ONT) sequencing strategies for bacterial genome analysis using the aquaculture-derived isolate 160P. Genomic DNA was extracted and sequenced on Illumina paired-end and ONT long-read platforms, and de novo assemblies were generated using SPAdes, Canu, Flye, and Unicycler under short-read-only, long-read-only, and hybrid workflows, followed by evaluation with QUAST assembly metrics. Among the tested approaches, the hybrid Unicycler assembly provided the highest contiguity, yielding seven contigs and a dominant 4.55 Mb contig consistent with near-complete chromosomal representation. Downstream analyses included functional genome annotation and in silico screening of antimicrobial resistance determinants (CARD), virulence-associated genes (VFDB), and secondary metabolite biosynthetic gene clusters (antiSMASH). Comparative genomic relatedness based on Average Nucleotide Identity (ANI) and digital DNA–DNA Hybridization (dDDH) indicated that 160P is most closely related to Aeromonas sobria CECT 4245^T yet falls below commonly applied species-level thresholds, supporting its placement as a genomically distinct lineage warranting further taxonomic investigation. Collectively, these findings underscore the value of hybrid sequencing for improving assembly continuity, enhancing annotation completeness, and strengthening taxonomic resolution in bacterial pathogen genomics. Full article