CAP3: A DNA sequence assembly program

Genomic and phenotypic insights into Serratia interaction with plants from an ecological perspective

We investigated the plant growth-promoting potential of two endophytic strains of Serratia marcescens, namely SmCNPMS2112 and SmUFMG85, which were isolated from the roots of the same maize (Zea mays) plant. The strains were evaluated in vitro for their ability to produce siderophores and indoleacetic acid, form biofilm, solubilize iron phosphate (Fe-P) and Araxá rock phosphate (RP), mineralize phytate, and for their ability to adhere and colonize host roots. Additionally, their plant growth-promoting potential was tested in vivo under greenhouse conditions using millet grown in soil under two fertilization schemes (triple superphosphate, TSP, or commercial rock phosphate, cRP). Both strains improved at least five physiological traits of millet or P content in soil. In order to elucidate the genetic basis of the plant growth-promoting ability of these strains, their genomes were compared. While both genomes exhibited a similar overall functional profile, each strain had unique features. SmCNPMS2112 contained genes related to arsenic and aromatic hydrocarbons degradation, whereas SmUFMG85 harbored genes related to rhamnolipid biosynthesis and chromium bioremediation. Also, we observe a unique repertoire of genes related to plant growth-promotion (PGP) in the SmUFMG85 genome, including oxalate decarboxylase (OxdC), associated with the catabolism of oxalic acid, and aerobactin siderophore (lucD) in the genome of SmCNPMS2112. The alkaline phosphatase was observed on two strains, but acid phosphatase was exclusive to SmUFMG85. Eighteen secondary metabolic gene clusters, such as those involved in the biosynthesis of macrolides and bacillomycin, among others, occur in both strains. Moreover, both genomes contained prophages, suggesting that viral-mediated horizontal gene transfer may be a key mechanism driving genomic variability in the endophytic environment. Indeed, the most genes unique and accessory of SmUFMG85 and SmCNPMS2112 were localized in genomic islands, highlighting genome plasticity and its underlying drivers. To investigate the ecological distribution of plant-interaction traits in the genus Serratia, the genomes of SmUFMG85 and SmCNPMS2112 strains were compared with those of other 19 Serratia strains of different species, which were isolated from different environments. We observe that many features for PGP are present in all genomes, regardless of niche, for instance: formation of flagella, fimbriae and pili, chemotaxis, biosynthesis of siderophores, indole-3-acetic acid (IAA) and volatile organic (VOC) and inorganic (VIC) compounds, such as acetoin and HCN. Also, all the analyzed genomes show an antimicrobial resistance repertoire of genes that confer resistance to several antibiotics belonging to the groups of aminoglycosides and quinolones, for instance. Also, from a niche partitioning perspective, secretion system preference and the ability to produce exopolysaccharides involved in biofilm formation are among the features that vary the most among strains, and most likely influence niche adaptation in Serratia spp., even though only the latter seems to be a feature specifically associated with virulence in the analyzed strains. Our results show that populations of bacteria sharing the same niche can present significant physiological and genomic differences, and reveal the intraspecific metabolic plasticity that underlie plant-bacteria interactions. Also, this study reveals the potential of two Serratia marcescens strains as bioinoculants in agriculture. Considering that Serratia spp. are regarded as low risk biological agents, despite the fact that they can be associated with human disease, we suggest that strain biosafety be evaluated using a combination of genome and phenotypic analyses, as presented herein.

Oral dysbiosis initiates periodontal disease in experimental kidney disease

BACKGROUND AND HYPOTHESIS

It is presently unclear why there is a high prevalence of periodontal disease in individuals living with chronic kidney disease. Whilst some have argued that periodontal disease causes chronic kidney disease, we hypothesized that alterations in saliva and the oral microenvironment in organisms with kidney disease may initiate periodontal disease by causing dysbiosis of the oral microbiota.

METHODS

Experimental kidney disease was created using adenine feeding and subtotal nephrectomy in rats, and by adenine feeding in mice. Loss of periodontal bone height was assessed using a dissecting microscope supported by micro-CT, light, confocal and electron microscopy, and immunohistochemistry. Salivary biochemistry was assessed using NMR spectroscopy. The oral microbiome was evaluated using culture-based and molecular methods, and the transmissibility of dysbiosis was assessed using co-caging and microbial transfer experiments into previously germ-free recipient mice.

RESULTS

We demonstrate that experimental kidney disease causes a reproducible reduction of alveolar bone height, without gingival inflammation or overt hyperparathyroidism but with evidence of failure of bone formation at the periodontal crest. We show that kidney disease alters the biochemical composition of saliva and induces progressive dysbiosis of the oral microbiota, with microbial samples from animals with kidney disease displaying reduced overall bacterial growth, increased alpha diversity, reduced abundance of key components of the healthy oral microbiota such as Streptococcus and Rothia, and an increase in minor taxa including those from gram-negative phyla Proteobacteria and Bacteroidetes. Co-housing diseased rats with healthy ones ameliorates the periodontal disease phenotype, whilst transfer of oral microbiota from mice with kidney disease causes periodontal disease in germ-free animals with normal kidney function.

CONCLUSIONS

We advocate that periodontal disease should be regarded as a complication of kidney disease, initiated by oral dysbiosis through mechanisms independent of overt inflammation or hyperparathyroidism.

Monogeneans on exotic Indian freshwater fish. 7. Results of a national study on ornamental fishes from 2019-2022

This study reports the results of a nationwide parasitological survey that was conducted from 2019 to 2022 to investigate the potential introduction of monogenean parasites into India via the ornamental fish trade. A total of 619 individual exotic ornamental fish representing 27 teleost species from nine families were collected from the country's major aquaria markets and examined for monogeneans. To identify monogeneans at the species level, we employed a morphometric analysis of sclerotised structures (haptoral and reproductive hard parts), as well as a molecular analysis of nuclear 28S rRNA and ITS2 regions. Indian conditions for importing exotic ornamental fish species require a pre-quarantine certificate, quarantine treatment, and post-quarantine follow-up. Despite these restrictions, 26 monogenean species from 12 known genera were detected and identified in 17 of the 27 fishes examined. Dactylogyrus was represented by a maximum of nine species, followed by Gyrodactylus with five. Cyprinidae was the most parasitised fish family (13 species), followed by Cichlidae (three species) and Helostomatidae, Poeciliidae, and Serrasalmidae (two species each). The majority of co-transported parasite species originated from Asia (65.38%, n = 17), followed by South America (23.07%, n = 6), North and Central America (7.69%, n = 2), and Africa (3.5%, n = 1). Three fish species were identified as the first host records for monogenean parasites: Chindongo socolofi for Cichlidogyrus tilapiae Paperna, 1960, Metynnis hypsauchen for Mymarothecium sp., and Betta splendens for Heteronchocleidus sp. In general, exotic populations had fewer parasite species than in their native distribution ranges.

Circular RNA discovery with emerging sequencing and deep learning technologies

Circular RNA (circRNA) represents a type of RNA molecule characterized by a closed-loop structure that is distinct from linear RNA counterparts. Recent studies have revealed the emerging role of these circular transcripts in gene regulation and disease pathogenesis. However, their low expression levels and high sequence similarity to linear RNAs present substantial challenges for circRNA detection and characterization. Recent advances in long-read and single-cell RNA sequencing technologies, coupled with sophisticated deep learning-based algorithms, have revolutionized the investigation of circRNAs at unprecedented resolution and scale. This Review summarizes recent breakthroughs in circRNA discovery, characterization and functional analysis algorithms. We also discuss the challenges associated with integrating large-scale circRNA sequencing data and explore the potential future development of artificial intelligence (AI)-driven algorithms to unlock the full potential of circRNA research in biomedical applications.

Molecular Characterization and Pathogenicity of Watermelon Isolates of Begomovirus cucurbitachinaense

Squash leaf curl China virus (SLCCNV) belongs to the species Begomovirus cucurbitachinaense in the genus Begomovirus and can infect some Cucurbitaceae crops except for watermelon (Citrullus lanatus). In this study, watermelon plants showing symptoms typical to begomovirus infection in field were observed in Zhejiang Province of China, and SLCCNV presence was identified through PCR and next-generation sequencing (NGS). The pairwise sequence identity of the DNA-A genome shows that SLCCNV watermelon isolate belongs to the SLCCNV/CN strain and shares 96% nucleotide identity with the previously sequenced SLCCNV/CN. An infectious clone of SLCCNV watermelon isolate was constructed using the tandem repeat fragment method. Through agrobacterium-mediated inoculation, the clone could induce systemic infection with typical symptoms in watermelon, melon (Cucumis melo), squash (Cucurbita pepo), pumpkin (Cucurbita maxima), wax gourd (Benicasa hispida), cucumber (Cucumis sativus), and N. benthamiana. It was further demonstrated that the progeny virions derived from the cloned watermelon isolate could be transmitted by whitefly rather than the sap. To the best of our knowledge, this is the first report of a natural infection of SLCCNV on watermelon in China, and the first complete report on the molecular characteristics and pathogenicity of watermelon-infecting SLCCNV in the world.

Too Far From Relatives? Impact of the Genetic Distance on the Success of Exon Capture in Phylogenomics

The exon capture approach allows for sequencing a large number of loci to reconstruct phylogenetic relationships at varying taxonomic levels. In order to efficiently recover the targeted loci, the probes designed to capture the exons need to be genetically sufficiently similar to bind to the DNA, with a proposed limit of 10% of divergence. However, this threshold has never been tested with a specific protocol. We have designed a set of probes to capture 1125 exons in the Neogastropoda (Mollusca, Gastropoda), processed with the same protocol from the field to the DNA sequencing to control for potential bias in DNA quantity and quality. We sequenced 30 different species, including 14 species of Neogastropoda and 16 species of Caenogastropoda non-Neogastropoda. Each species includes five specimens, for a total of 150 specimens, and for four specimens among the 150, DNA extracts were aliquoted in four samples, sequenced separately, to estimate the intraspecific and intraspecimen variability in capture success. Our results confirm the impact of genetic distance on the success of exon capture with a negative linear correlation between the genetic distance and the number of exons captured for each sample. Consequently, designing new capture probes would allow for capturing exons in genetically more distant groups without the need to redesign a new set of exons.

Genomic Repertoire of Twenty-Two Novel Vibrionaceae Species Isolated from Marine Sediments

The genomic repertoire of vibrios has been extensively studied, particularly regarding their metabolic plasticity, symbiotic interactions, and resistance mechanisms to environmental stressors. However, little is known about the genomic diversity and adaptations of vibrios inhabiting deep-sea marine sediments. In this study, we investigated the genomic diversity of vibrios isolated from deep-sea core sediments collected using a manned submersible off Japan. A total of 50 vibrio isolates were obtained and characterized phenotypically, and by genome sequencing. From this total, we disclosed 22 novel species examining genome-to-genome distance, average amino acid identity, and phenotypes (Alivibrio: 1; Enterovibrio: 1; Photobacterium: 8; Vibrio: 12). The novel species have fallen within known clades (e.g., Fisheri, Enterovibrio, Profundum, and Splendidus) and novel clades (JAMM0721, JAMM0388, JAMM0395). The 28 remainder isolates were identified as known species: Aliivibrio sifiae (2), A. salmonicida (1), Enterovibrio baiacu (1), E. norvegicus (1), Photobacterium profundum (3), P. angustum (1), P. chitiniliticum (1), P. frigidiphilum (1), Photobacterium indicum (1), P. sanguinicancri (1). P. swingsii (2), Vibrio alginolyticus (3), V. anguillarum (1), V. campbellii (1), V. fluvialis (1), V. gigantis (1), V. lentus (1), V. splendidus (4), and V. tasmaniensis (1). Genomic analyses revealed that all 50 vibrios harbored genes associated with high-pressure adaptation, including sensor kinases, chaperones, autoinducer-2 (AI-2) signaling, oxidative damage repair, polyunsaturated fatty acid biosynthesis, and stress response mechanisms related to periplasmic and outer membrane protein misfolding under heat shock and osmotic stress. Additionally, alternative sigma factors, trimethylamine oxide (TMAO) respiration, and osmoprotectant acquisition pathways were identified, further supporting their ability to thrive in deep-sea environments. Notably, the genomes exhibited a high prevalence of antibiotic resistance genes, with antibiotic efflux pumps being the most abundant group. The ugd gene expanded in number in some novel species (Photobacterium satsumensis sp. nov. JAMM1754: 4 copies; Vibrio makurazakiensis sp. nov. JAMM1826: 3 copies). This gene may confer antibiotic (polymyxin) resistance to these vibrios.

Theobroma cacao Virome: Exploring Public RNA-Seq Data for Viral Discovery and Surveillance

Cocoa (Theobroma cacao L.) is a major agricultural commodity, essential for the global chocolate industry and the livelihoods of millions of farmers. However, viral diseases pose a significant threat to cocoa production, with Badnavirus species causing severe losses in Africa. Despite its economic importance, the overall virome of T. cacao remains poorly characterized, limiting our understanding of viral diversity and potential disease interactions. This study aims to assess the cocoa-associated virome by analyzing 109 publicly available RNA-seq libraries from nine BioProjects, covering diverse conditions and geographic regions. We implemented a comprehensive bioinformatics pipeline integrating multiple viral sequence enrichment steps, a hybrid assembly strategy using different assemblers, and sequence similarity searches against NCBI non-redundant databases. Our approach identified ten putative novel viruses associated with the cocoa microbiome and a novel Badnavirus species. These findings provide new insights into the viral landscape of T. cacao, characterizing the diversity of cacao-associated viruses and their potential ecological roles. Expanding the catalog of viruses associated with cocoa plants not only enhances our understanding of plant-virus-microbiome interactions but also contributes to the development of more effective disease surveillance and management strategies, ultimately supporting sustainable cocoa production.

Rapidly obtaining genome sequence of Severe Fever with Thrombocytopenia Syndrome virus directly from clinical serum specimen using long amplicon based nanopore sequencing workflow

Severe Fever with Thrombocytopenia Syndrome (SFTS) is an emerging viral infectious disease discovered in 2009 with a high fatality rate and continuing to pose a public threat for many countries. Surveillance of genome sequence of its causative pathogen, Severe Fever with Thrombocytopenia Syndrome virus (SFTSV), could provide evidence for SFTS control, diagnosis method update, viral evolution dynamic and pathogenic mechanism research, etc. Here, we developed a workflow for rapidly obtaining the genome sequence of SFTSV directly from clinical samples to facilitate the viral genome sequence surveillance. Three pairs of primers targeting the terminal conserved regions of three segments were newly designed to more efficiently enrich nearly whole viral genome. Datasets comprised reads generated in different timeframes for four simulated samples with high to low serially diluted viral loads were subjected to analysis. For a simulated sample with a Ct value of 35 and sequenced for 10 minutes, the average coverage depth could reach over 700x, and the genome coverage could reach 98.69% after subtraction of the primer sequence, and the sequence identity with Sanger sequencing could reach over 99.91%. Two clinical serum specimens were used to validate the workflow and sequences were successfully obtained. A long amplicon based nanopore sequencing workflow was established, which could finish in 10 hours from serum specimen to genome sequence. This workflow has potential to provide essential information for SFTS control and support further pathogenesis research.

Endogenous retrovirus loci and induced changes in gene expression in Japanese indigenous chickens

When retroviruses infect germ cells and are transmitted to offspring, they become endogenous retroviruses (ERVs), whose insertions may influence the expression of nearby genes. In this study, we aimed to identify the genomic loci of ERVs in commercial broiler (Ross308), Tosa-Jidori, and Yakido chickens, as well as to elucidate their impact on neighboring gene expression. Whole-genome data were obtained using next-generation sequencing, and candidate ERV loci were identified using the RetroSeq software. The Integrative Genomics Viewer tool was used to confirm target site duplications (TSDs) as evidence of ERV insertions. All reads within 200 bp of these TSDs were extracted to create contigs, confirming the presence of ERV sequences in the contigs using BLASTN. Gene expression levels were estimated by focusing on genes located near the 172 identified ERV loci. Among these, 119 loci were detected in broiler chickens, 80 in Tosa-Jidori chickens, and 86 in Yakido chickens, with 28 loci shared among them. Moreover, of these 172 loci, 75 were located within or near genes. Significant differences in gene expression were observed for N-acetylated alpha-linked acidic dipeptidase 2 (NAALAD2) and phosphoribosylaminoimidazolesuccinocarboxamide synthase (PAICS) depending on the presence of ERV insertions. These results suggest that ERV insertions may influence the expression of NAALAD2 and PAICS, providing insights into the genetic diversity and evolutionary background of commercial and indigenous chickens. Understanding the effects of ERV insertions on gene expression can inform future genetic research and poultry breeding programs aimed at improving health and productivity.

Genome mining reveals the biosynthetic potential of a novel Lysinibacillus zambalensis sp. nov., isolated from a hyperalkaline spring

A novel bacterium, designated as strain M3T, was isolated from a hyperalkaline spring in the Philippines and identified as a new species within the genus Lysinibacillus through 16 S rRNA gene sequence and genomic analyses. Although strain M3T shared a high 16 S rRNA gene sequence similarity (> 98.7%) with many Lysinibacillus species, the digital DNA-DNA hybridization and orthologous average nucleotide identity values between strain M3T and its closet relative, Lysinibacillus xylanilyticus DSM 23,493T, were 41.2% and 90.6%, respectively-both below the established threshold for prokaryotic species delineation. Genome mining of the 5.3 Mbp-draft genome of strain M3T revealed eight biosynthetic gene clusters, which shared little sequence similarity with characterized clusters, suggesting the potential for encoding novel specialized metabolites. The cells of strain M3T were Gram-stain-positive, aerobic, rod-shaped, non-motile, and capable of endospore formation. Optimum growth was observed at 30 °C, pH 8.0, and 0.5% (w/v) NaCl. The major respiratory quinone was menaquinone-7, and the predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and two unknown phospholipids. Its fatty acid profile showed an elevated level of iso-C15:0, and the peptidoglycan type was determined to be A4α (L-Lys-D-Asp). This study contributes to the growing database and understanding of the genus and aims to help drive future research on the bioactive potential of the genus. Lysinibacillus zambalensis sp. nov. is proposed with strain M3T as the type strain (= TISTR 10640T = BIOTECH 10973T).

Streptococcus pneumoniae serotype 33H: a novel serotype with frameshift mutations in the acetyltransferase gene wciG

BACKGROUND

Streptococcus pneumoniae (the pneumococcus) is a leading cause of community-acquired pneumonia. Pneumococci are categorised into serotypes, based on the type of capsular polysaccharide produced, which has important implications for virulence, vaccine impact and global surveillance. Recently, we identified a novel serotype, which we named 33G, that is comprised of an O-acetylated hexasaccharide repeat unit. In this study, we report and describe variants of 33G, designated 33G-like, which we isolated from the nasopharynx of two adults hospitalised with pneumonia in Mongolia.

METHODS

Serological comparison of 33G and 33G-like pneumococci were conducted by Quellung serotyping. Genetic analysis of the capsular polysaccharide loci was performed using whole genome sequencing. Polysaccharide composition was determined using 1H nuclear magnetic resonance.

RESULTS

By Quellung serotyping, 33G pneumococci type as both 10B and 33B whereas 33G-like pneumococci type as both 10B and 33F. Genomic analysis of the capsular polysaccharide locus revealed 33G-like loci are identical to 33G, except for frameshift mutations in the wciG gene which encodes an acetyltransferase responsible for the O-acetylation of beta-galactofuranose (β-Galf) in the capsular polysaccharide repeat unit. We constructed an artificial 33G-like by deleting wciG in a 33G strain and confirmed this gene was responsible for the serological differences between 33G and 33G-like pneumococci. Lastly, 1H nuclear magnetic resonance confirmed the O-acetylation present in the 33G polysaccharide is absent in the 33G-like polysaccharide.

CONCLUSIONS

Here, we have provided serological, genetic and biochemical evidence that the 33G-like capsule differs to 33G and all other pneumococcal serotypes, meeting the requirements to be designated as a new serotype, which we have named 33H.

The enigmatic genus Malacophrys Kahl, 1926 (Ciliophora: Intramacronucleata) belongs to the class Oligohymenophorea

The ciliate genus Malacophrys has been incertae sedis for more than 50 years in what is now subphylum Intramacronucleata, provisionally assigned to three different classes by various authors. Of the three species included in the genus, M. sphagni and the type species, Malacophrys rotans, have not been studied by modern methods and M. viridis, although morphologically well-described, lacks molecular characterization. We identified two freshwater ciliates as morphologically consistent with two members of Malacophrys, namely M. rotans and M. viridis. We studied one population of M. rotans, using in vivo observation and silver carbonate and silver nitrate impregnation, and two populations of M. viridis, using in vivo observation, silver carbonate impregnation, and 18S rRNA gene sequencing. Phylogenetic analyses strongly support the position of M. viridis in the class Oligohymenophorea. Morphologic features suggest Malacophrys rotans belongs to order Tetrahymenida, but a confident phylogenetic assignment awaits its molecular sequencing. Differences between their oral structures and silverline patterns indicate that M. rotans and M. viridis likely belong to different genera. A formal separation at the genus level awaits molecular characterization of the type species, M. rotans.

Observed Prevalence and Characterization of Fluoroquinolone-Resistant and Multidrug-Resistant Bacteria in Loggerhead Sea Turtles (Caretta caretta) from the Adriatic Sea

Background/Objectives: Antimicrobial resistance (AMR) is a major global health concern with profound implications for human, animal, and environmental health. Marine ecosystems are emerging as reservoirs of resistant bacteria due to contamination from anthropogenic activities. This study aimed to investigate fluoroquinolone-resistant and multidrug-resistant bacteria in loggerhead sea turtles (Caretta caretta). Methods: Cloacal swabs were collected from 28 loggerhead sea turtles at a rescue center in southern Italy. Swabs were cultured in nutrient media supplemented with enrofloxacin. Bacterial isolates underwent identification by MALDI-TOF, antimicrobial susceptibility testing, and assessment for multidrug resistance. Conjugation experiments evaluated the transferability of enrofloxacin resistance. Results: Thirty-six enrofloxacin-resistant bacterial strains were isolated from 22 turtles. The identified species included Vagococcus fluvialis (13 strains), Citrobacter freundii (5), Escherichia coli (6), and Pseudomonas mendocina (4). Thirty-five isolates exhibited multidrug resistance, with resistance to critically important antibiotics such as imipenem observed in C. freundii and Enterobacter faecium. Conjugation experiments showed no transfer of resistance genes. Conclusions: The study highlights the prevalence of fluoroquinolone-resistant and multidrug-resistant bacteria in C. caretta, implicating marine environments as reservoirs of AMR. The findings underscore the need for stricter regulation of antimicrobial use and monitoring of resistance dissemination in marine ecosystems. These results contribute to understanding AMR dynamics within the One Health framework, emphasizing the interconnectedness of environmental, animal, and human health.

Transcriptomic Divergence and Associated Markers Between Genomic Lineages of Silver Catfish (Rhamdia quelen)

Rhamdia quelen is a catfish widely distributed throughout South America, characterized by a complex taxonomic history. This species is a valuable resource for both fisheries and aquaculture. Due to its cultural and economic importance, it has been prioritized for conservation in the Neotropical region. Population genomics studies supported two main lineages latitudinally distributed (North and South) in the Neotropical basins Río de la Plata and Laguna Merín based on current genetic isolation and signals of local adaptation. In this study, we characterized the R. quelen transcriptome in brain, head kidney, liver, skeletal muscle, testis, and ovary by RNAseq to target genes and associated markers involved in key adaptive traits. After filtering, a comprehensive catalog of 24,433 transcripts was annotated, providing insights into the immune function of head kidney and liver, the association of brain with the endocrine system, and the metabolic function of liver. Skeletal muscle and brain expressed genes associated with growth were also identified. Transcriptomic differences suggestive of adaptation to temperature and salinity were revealed between North and South genomic lineages. A total of 100,045 SNPs loci were identified within transcripts, most of them (78.8%) showing low genetic differentiation between lineages (FST ≤ 0.100). However, 2504 loci (2.5%) showed high differentiation (FST ≥ 0.800), some of them located within genes associated with putative adaptation of genomic lineages to environmental factors such as temperature and salinity. These SNPs represent useful gene markers for future functional and population genomic studies for sustainable management of wild populations and their application in breeding programs.

Antibacterial Activity, GC MS Analysis and In Silico Validation of Bioactive Compound from Endophytic Fungus Lasiodiplodia pseudotheobromae EF-9

Secondary metabolites synthesized by endophytic fungi have garnered significant interest for their broad applications in treating various ailments. In this study involving 20 plant samples, 11 endophytic fungi were isolated and cultured, and Lasiodiplodia pseudotheobromae EF-9, derived from Hibiscus rosa-sinensis, demonstrated greater antibacterial efficacy than the other isolated endophytes. Phylogenetic analyses using 18S rRNA gene confirmed the EF-9 identity as L. pseudotheobromae. Following mass production, the active compound was partially purified using column chromatography. The fraction collected at the 60th min exhibited good antibacterial activity against Bacillus coagulans (MTCC 6735) and Shigella flexneri (ATCC 12022), with an inhibition zone of approximately 20 mm in diameter. UV spectral studies revealed a wide absorption band at 430 nm. High Performance Liquid Chromatography (HPLC) of the active fraction showed a distinct peak with a retention time of 4.216 min at 430 nm. Gas Chromatography-Mass Spectrometry (GC-MS) identified the active compound in the L. pseudotheobromae EF-9 culture broth extract as Bis(2-ethylhexyl) phthalate, which displayed a peak at 16.856 min and covered 66.69 % of the area in the spectral analysis.

Comparative analysis of the mitochondrial genomes of the soft-shelled turtles Palea steindachneri and Pelodiscus axenaria and phylogenetic implications for Trionychia

Soft-shelled turtles, or Trionychia, are an enigmatic and fascinating group due to their specific morphological features and ecological adaptations. Based on mitochondrial DNA (mtDNA) and/or nuclear markers, previous studies showed the incongruent phylogenetic topologies within Trionychia (e.g., the Palea and its closely related species). In order to resolve the equivocal relationships and obtain some "genome-level" common evolutionary characters of soft-shelled turtles, in this study, we assembled and annotated the complete mitochondrial genomes of Palea steindachneri and Pelodiscus axenaria, both naturally distributed in Asia. The sizes of the two mitochondrial genomes were 16,811 bp and 17,143 bp, respectively. Typical vertebrate animal mtDNA features were observed, such as the usual gene components and arrangements (37 genes with a non-coding control region) and the A + T biased nucleotide compositions on the light strand (61.5% and 62.7%, respectively). All conserved blocks common to the vertebrates control region except for the extended terminal associated sequences (ETAS2) were found in the two soft-shelled turtles. The ω ratio averaged over all sites of each protein-coding gene (PCG) was below 1, which indicated purifying selection at the gene-wide level. However, a positive selection site at the 350-codon position in the cytb gene was detected, as estimated by Bayes empirical Bayes (BEB) analysis. Compared with the gene subsets, the mitogenomes provided the most robust phylogenetic resolution. The monophyly of the clades Amydona, Gigantaesuarochelys, and Apalonia was well supported. Topology discrepancies were observed among different datasets (e.g., the positions of Lissemys and Palea), reflecting the heterogeneous phylogenetic signals in the soft-shelled turtle mitogenomes. Precise date estimation based on Bayesian relaxed clock analyses indicated that the crown group age of extant Trionychia was approximately 115.84 Ma (95% HPD: 91.33-142.18 Ma). Paleoclimate changes, especially the Eocene - Oligocene transition, could be responsible for the speciation in these groups. Our results reiterated the necessity and effectiveness of incorporating entire mitochondrial genomes to delineate phylogenetic relationships in chelonian phylogeny studies.

Treatment of avian malaria in captive African penguins (Spheniscus demersus) by the combination of atovaquone and proguanil hydrochloride

Avian malaria, a vector-borne disease caused by Plasmodium spp., poses significant threats to various bird populations, particularly captive penguins like the endangered African penguin (Spheniscus demersus). Penguins, originating from regions with low malaria prevalence, are highly susceptible when housed in malaria-permissive areas. This study evaluates the efficacy of an atovaquone/proguanil hydrochloride treatment protocol to manage avian malaria in a captive African penguin colony in an Italian zoo. The study involved 30 penguins monitored over 3 years. Thirteen penguins tested positive for Plasmodium spp., with 11 undergoing treatment. The treatment protocol consisted of atovaquone/proguanil hydrochloride (10/4 mg/kg) administered orally for 3 days, repeated after a week. Post-treatment monitoring at 7, 30, and 60 days, and follow-ups up to 2 years, showed that all but one penguin cleared the infection. The treatment was well tolerated, with no adverse effects observed. The findings suggest that this protocol is effective as a treatment of avian malaria and could be a valuable tool in avian malaria management, particularly for endangered species in captivity. However, the persistence of Plasmodium relictum in one case highlights the need for careful post-treatment monitoring to prevent recurrence or reinfection. The study underscores the importance of developing tailored antimalarial protocols for captive birds to enhance conservation efforts and mitigate the risks posed by avian malaria.

Building resource-efficient community databases using open-source software

The unprecedented volume of big data being routinely generated for nonmodel crop species, coupled with advanced technology enabling the use of big data in breeding, gives further impetus for the need to have access to crop community databases, where all relevant data are curated and integrated. Funding for such databases is, however, insufficient and intermittent, resulting in the data being underutilized. While increased awareness of the importance of funding databases is important, it is practically necessary to find a more efficient way to build a community database. To meet the need for integrated database resources for various crop genomics, genetics, and breeding research communities, we have built five crop databases over the last decade using an open-source database platform and software. We describe the system and methods used for database construction, curation, and analysis protocols, and the data and tools that are available in these five crop databases. Database URL: The Genome Database for Rosaceae (GDR, www.rosaceae.org), the Genome Database for Vaccinium (GDV, www.vaccinium.org), the Citrus Genome Database (CGD, www.citrusgenomedb.org), the Pulse Crop Database (PCD, www.pulsedb.org), and CottonGen (www.cottongen.org).

Accurate assembly of full-length consensus for viral quasispecies

BACKGROUND

Viruses can inhabit their hosts in the form of an ensemble of various mutant strains. Reconstructing a robust consensus representation for these diverse mutant strains is essential for recognizing the genetic variations among strains and delving into aspects like virulence, pathogenesis, and selecting therapies. Virus genomes are typically small, often composed of only a few thousand to several hundred thousand nucleotides. While constructing a high-quality consensus of virus strains might seem feasible, most current assemblers only generated fragmented contigs. It's important to emphasize the significance of assembling a single full-length consensus contig, as it's vital for identifying genetic diversity and estimating strain abundance accurately.

RESULTS

In this paper, we developed FC-Virus, a de novo genome assembly strategy specifically targeting highly diverse viral populations. FC-Virus first identifies the k-mers that are common across most viral strains, and then uses these k-mers as a backbone to build a full-length consensus sequence covering the entire genome. We benchmark FC-Virus against state-of-the-art genome assemblers.

CONCLUSION

Experimental results confirm that FC-Virus can construct a single, accurate full-length consensus, whereas other assemblers only manage to produce fragmented contigs. FC-Virus is freely available at https://github.com/qdu-bioinfo/FC-Virus.git .

Population genetics analysis based on mitochondrial cytochrome c oxidase subunit I (CO1) gene sequences of Cottus koreanus in South Korea

BACKGROUND

The freshwater sculpin Cottus koreanus is endemic to the Korean Peninsula and has a fluvial life history. However, its population has been greatly reduced and it is now listed as an endangered class II species.

OBJECTIVE

To obtain important information for its conservation, we examine the genetic diversity, population structure, and demographic history of C. koreanus through mitochondrial cytochrome c oxidase subunit I (CO1) gene sequence analysis.

METHODS

We analyzed the CO1 gene sequences of 430 individuals of C. koreanus from 23 populations in South Korea.

RESULTS

In all, 32 haplotypes were defined by 124 variable nucleotide sites, of which 28 were unique haplotypes not shared with other regional populations. All sampled populations had high haplotype diversity (Hd = 0.941) and low nucleotide diversity (π = 0.0146). Median-joining network analysis identified two divergent clusters: cluster I that had unique haplotype patterns assigned to each population and cluster II that had a star-like pattern. Each was supported by pairwise FST values and hierarchical analysis of molecular variance. The results of the mismatch distribution, goodness-of-fit test, and extended Bayesian skyline plot analysis showed that cluster I has experienced a gradual population expansion since the last glacial maximum, while cluster II experienced a sudden one. The results of neutrality testing supported the results for cluster II but the signal was weak.

CONCLUSIONS

C. koreanus inhabits the upper reaches of rivers and has extremely low dispersal ability, resulting in unique genetic structure patterns among populations. Therefore, all populations should be managed and conserved separately.

Wild yeast isolation by middle-school students reveals features of populations residing on North American oaks

Features of the natural life cycle of the budding yeast Saccharomyces cerevisiae were crucial to its domestication as a laboratory experimental model, especially the ability to maintain stable haploid clones and cross them at will to combine alleles via meiosis. Stable haploidy results from mutations in HO, which encodes an endonuclease required for haploid-specific mating-type switching. Previous studies found an unexpected diversity of HO alleles among natural isolates within a small geographic area. We developed a hands-on field and laboratory activity for middle-school students in Denver, CO, USA, to isolate wild yeast from oak bark, identify species via DNA sequencing, and sequence HO from S. cerevisiae isolates. We find limited HO diversity in North American oak isolates, pointing to efficient, continuous dispersal across the continent. In contrast, we isolated the "dairy yeast," Kluyveromyces lactis, from a tree <10 m away and found that it represents a new population distinct from an oak population in an adjacent state. The outreach activity partnered middle-school, high-school, and university students in making scientific discoveries and can be adapted to other locations and natural yeast habitats. Indeed, a pilot sampling activity in southeast Texas yielded S. cerevisiae oak isolates with a new allele of HO and, from a nearby prickly pear cactus, a heat-tolerant isolate of Saccharomyces paradoxus.

Frameshift variation in the HMG-CoA reductase gene and unresponsiveness to cholesterol-lowering drugs in type 2 diabetes mellitus patients

Dyslipidemia, an imbalance in blood lipid levels, is a frequent complication of type 2 diabetes mellitus (DM2) and heightens the risk of cardiovascular diseases (CVDs). Statins, which inhibit 3-hydroxy-3-methylglutaryl-CoA reductase, are potent competitive inhibitors that reduce plasma cholesterol levels. However, individual responses to statins can vary markedly, possibly due to genetic variations in the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) gene. This study aimed to investigate the pharmacogenetic relationship between the HMGCR gene and hypercholesterolemia in type 2 diabetes mellitus patients who respond differently to atorvastatin, as well as in healthy individuals. Ninety participants were involved, including sixty with type 2 diabetes mellitus and hypercholesterolemia, and thirty healthy individuals. They were randomly assigned to three groups: responsive (received atorvastatin 40 mg), non-responsive (also received atorvastatin 40 mg), and control. Both responsive and non-responsive groups underwent fasting. Biochemical tests were conducted, followed by genetic analysis to identify mutations in the HMGCR gene. The effects of statins in each group were assessed using analysis of variance (ANOVA) and post hoc Tukey's Honestly Significant Difference (HSD) analysis. Atorvastatin 40 mg was administered to assess its efficacy in reducing cholesterol levels in patients with hypercholesterolemia and type 2 diabetes mellitus. The control group exhibited similar cholesterol levels to the responsive group (cholesterol < 200 mg/dl). However, both control and responsive groups significantly differed from the non-responsive group, which had markedly elevated cholesterol levels (> 240 mg/dl). Genetic analysis revealed a cytosine nucleotide insertion in the catalytic domain of the HMGCR gene in only two non-responsive participants to atorvastatin 40 mg therapy. These two patients showed non-responsiveness to atorvastatin 40 mg due to a genetic mutation in the HMGCR gene. This mutation altered the amino acid sequence in the flap domain, replacing isoleucine with a stop codon. As a result, translation was prematurely terminated, leading to the production of truncated proteins.

Characterization of phytoplasma associated with wilt disease in coconut and approaches for its sensitive diagnostics

Coconut wilt associated with phytoplasma presence is a serious disease that threatens the coconut plantations in South India. Symptoms progress rapidly and cause complete destruction of coconut palm which results in severe economic loss to farmers. Survey in the areas of Thanjavur and Coimbatore districts revealed disease incidence upto 2.5 % and the affected palms exhibited unique symptoms, which differ from the root wilt disease symptoms reported so far. Nested PCR with universal primers and multilocus characterization of tuf and certain rp genes confirmed the presence of phytoplasmas. The 16S rRNA ribosomal gene sequence-based identification assigned the coconut wilt phytoplasma to the 'Candidatus Phytoplasma asteris' species. To achieve timely management of the disease and also to check its spread, Loop Mediated Isothermal Amplification (LAMP) and real-time LAMP diagnostics by targeting the 16S rRNA gene, were established for rapid and specific detection of phytoplasma presence. PCR with LAMP outer primers was carried out and sequence analysis confirmed the amplification of the 16S rRNA gene of phytoplasma. LAMP assay positive samples showed the color shift from violet to blue and was further confirmed by the ladder-like bands produced during the amplification. Diseased samples also generated a unique annealing peak at 87 ± 0.5 °C in the real-time LAMP assay. The LAMP protocol devised will be useful for quick and sensitive detection of this phytoplasma and it has potential application to detect phytoplasma presence in suspected coconut palms and to allow screening of nursery seedlings to ensure disease free planting.

Population genetic structure and demographic history of short mackerel, Rastrelliger brachysoma, in the Gulf of Thailand

The short mackerel Rastrelliger brachysoma (Bleeker 1851) is an important fish in the Gulf of Thailand (GoT). The biology of this species has been intensively studied, but its genetic diversity is little known. The genetic diversity, population genetic structure, and demographic history of this species in the GoT were studied using complete mt control region sequences. The CR sequences of 455 mackerel samples collected from 23 localities at four fishing grounds revealed 333 haplotypes with haplotype diversity (h) per population, ranging between 0.8933 and 1.000, with an average of 0.9781. In turn, the nucleotide diversity (µ) ranged between 0.0119 ± 0.0060 and 0.0333 ± 0.0174, with an average of 0.0220 ± 0.00059.A haplotype network analysis showed that all sequences segregated into two subgroups named, clade I and clade II. Two clades were separated by 26 mutational steps. Each clade formed star-like clusters with many haplotypes derived from a common haplotype. Moreover, an analysis of molecular variance (AMOVA) revealed no significant differences among the studied localities, suggesting the presence of a single population in the GoT. Pairwise differences between samples from different fishing regions also indicated no population structure. Both Tajima's D and Fu's FS statistics were highly significant for the two clades but nonsignificant for the entire population according to a mismatch distribution analysis. These results confirmed that both clades experienced demographic expansion. The estimated expansion times for clade I and clade II were 1,542.307 years (1.5423 ka BP) and 7,602.541 (7.6025 ka BP) years, respectively.

Interaction Between Translation Initiation Factor eIF4E in Banana and the VPg Protein of Banana Bract Mosaic Virus Reveals Potential Targets for Genome Editing

Plant viruses need host factors to complete their life cycle. The eukaryotic translation initiation factor 4E (eIF4E) and its isoforms are the host factors essential for infection by plant viruses in the genus Potyvirus. The present study describes the characterization of eIF4E gene in banana cultivar Nendran, and its interaction with the viral genome-linked protein (VPg) of banana bract mosaic virus (BBrMV). The in-silico analysis of 853 bp coding mRNA region of eIF4E revealed the presence of five exons. The deduced amino acid sequence had 99.58% identity with the predicted protein sequence of the eIF4E-1 in Musa acuminata subspecies malaccensis. Expression profiling of eIF4E gene in banana cultivar Nendran using qRT-PCR revealed up to 16.9-fold up-regulation of the gene in response to BBrMV infection, indicating its role in disease development. The three-dimensional models of the eIF4E and VPg proteins were generated to deduce the precise interaction between the two proteins. Using the online server ZDOCK, ten interaction complexes were obtained. In nine out of the ten complexes, the maximum number of residues of the eIF4E interacted with the Tyrosine-63rd residue of VPg. The corresponding nucleotides were identified as the potential targets for editing the host eIF4E gene to impart potyvirus resistance.

Comparative transcriptomics suggests a highly species-specific nature of the phenotypic plasticity associated with the outbreaks of the two main pest locusts

BACKGROUND

Locust outbreaks cause devastation and provide material for fundamental research. They associate with a case of phenotypic plasticity whereby the shift between the two extremes of the polyphenism (i.e., gregarious phase versus solitarious phase) affects behaviour as well as most aspects of the locusts' biology. The phenotypic changes imply changes in gene expression, the changes in behaviour characterize the locusts' phase change, and the changes in the Central Nervous System (CNS) control the changes in behaviour. Thus, understanding and tackling the phenomenon requires studying the gene expression changes that the locusts' CNS undergoes between phases. The genes that change expression the same way in different locusts would be ancestrally relevant for the phenomenon in general and some of those that change expression in a species-specific way would be relevant for the phenomenon in species-specific way.

METHODS

Here, we use available raw sequencing reads to build transcriptomes and to compare the gene expression changes that the CNS of the two main pest locusts (Schistocerca gregaria and Locusta migratoria) undergo when they turn gregarious. The differentially expressed genes resulting from this comparative study were compared with the content of the L. migratoria core transcriptional phase signature genes database. Our aim is to find out about the species-specificity of the phenomenon, and to highlight the genes that respond in the same way in both species.

RESULTS

The locust phase change phenomenon seems highly species-specific, very likely due to the inter-specific differences in the material used, and in the biology and life conditions of the different locust species. Research on locust outbreaks, gregariousness and swarming would therefore benefit from considering each locust species apart, and caution is needed when extrapolating results between species-as no species seems representative of all locust species. Still, the 109 genes and 39 non-annotated sequences that we found to change expression level the same way in the two main pest locusts, especially those previously reported as core transcriptional phase signature genes in L. migratoria's CNS-related tissues (10 and 1, respectively), provide material for functional testing in search for important genes to better understand, or to fight against locust outbreaks in a non-species-specific way. The large set of genes that respond in a species-specific way provide material for comparing, understanding and tackling the locust's phase change phenomenon in a species-specific way. The still uncharacterized transcripts that change expression either in a species-specific or the same way between the two species studied here provide material for gene discovery. Functional testing and confirmation are needed in all cases.

Identification and mapping of QTLs and their corresponding candidate genes controlling high night-time temperature stress tolerance in wheat (Triticum aestivum L.)

With every 1°C rise in temperature, yields are predicted to decrease by 5%-6% for both cool and warm season crops, threatening food production, which should double by 2050 to meet the global demand. While high night-time temperature (HNT) stress is expected to increase due to climate change, limited information is available on the genetic control of the trait, especially in wheat (Triticum aestivum L.). To identify genes controlling the HNT trait, we evaluated a doubled haploid (DH) population developed from a cross between an HNT tolerant line KSG1203 and KSG0057, a selection out of a mega variety PBW343 from South East Asia that turned out to be HNT susceptible. The population, along with the parents, were evaluated under 30°C night-time (HNT stress) keeping the daytime temperature to normal 22°C. The same daytime and 16°C night-time temperature were used as a control. The HNT treatment negatively impacted all agronomic traits under evaluation, with a percentage reduction of 0.5%-35% for the tolerant parent, 8%-75% for the susceptible parent, and 8%-50% for the DH population. Performed using sequencing-based genotyping, quantitative trait locus (QTL) mapping identified 19 QTLs on 13 wheat chromosomes explaining 9.72%-28.81% of cumulative phenotypic variance for HNT stress tolerance, along with 13 that were for traits under normal growing conditions. The size of QTL intervals ranged between 0.021 and 97.48 Mb, with the number of genes ranging between 2 and 867. A candidate gene analysis for the smallest six QTL intervals identified eight putative candidates for night-time heat stress tolerance.

Genomic analysis of Salmonella Heidelberg isolated from the Brazilian poultry farms

The rapid expansion of broiler chicken production in Brazil has presented significant sanitation challenges within the poultry industry. Among these challenges, Salmonella enterica subsp. enterica serotype Heidelberg stands as a contributor to global salmonellosis outbreaks. This study analyzed 13 draft genomes of Salmonella Heidelberg isolated from the pre-slaughter broiler chickens farms in Brazil. By conducting in silico analysis of these genomes, the study investigated genome similarity based on single nucleotide polymorphisms (SNPs) and identified genes encoding resistance to antimicrobials, sanitizers, and virulence factors. Furthermore, mobile genetic elements (MGE) were identified to assess their potential role in propagating genes through horizontal gene transfer. A risk classification was also applied based on the resistomes. The genomes revealed a high prevalence of genes conferring resistance to aminoglycosides, fosfomycin, sulfonamides, tetracycline, and genes linked to quaternary ammonium resistance. The study also uncovered six Salmonella pathogenicity islands (SPI) and over 100 genes encoding virulence factors. The association of MGE with antibiotic-resistant genes sul2 and blaCMY-2 raised concerns about the potential transfer to other bacteria, posing a substantial risk for spreading resistance mechanisms according to established risk protocols. Additionally, SNP analysis indicated close phylogenetic relationships among some isolates, suggesting a common origin. This study enhances our understanding of Salmonella Heidelberg strains by identifying key risk factors for transmission and revealing the association between resistance genes and MGEs. This insight provides a foundation for developing and implementing effective control, monitoring, and treatment strategies in the poultry industry.

Mating systems and recombination landscape strongly shape genetic diversity and selection in wheat relatives

How and why genetic diversity varies among species is a long-standing question in evolutionary biology. Life history traits have been shown to explain a large part of observed diversity. Among them, mating systems have one of the strongest impacts on genetic diversity, with selfing species usually exhibiting much lower diversity than outcrossing relatives. Theory predicts that a high rate of selfing amplifies selection at linked sites, reducing genetic diversity genome-wide, but frequent bottlenecks and rapid population turn-over could also explain low genetic diversity in selfers. However, how linked selection varies with mating systems and whether it is sufficient to explain the observed difference between selfers and outcrossers has never been tested. Here, we used the Aegilops/Triticum grass species, a group characterized by contrasted mating systems (from obligate outcrossing to high selfing) and marked recombination rate variation across the genome, to quantify the effects of mating system and linked selection on patterns of neutral and selected polymorphism. By analyzing phenotypic and transcriptomic data of 13 species, we show that selfing strongly affects genetic diversity and the efficacy of selection by amplifying the intensity of linked selection genome-wide. In particular, signatures of adaptation were only found in the highly recombining regions in outcrossing species. These results bear implications for the evolution of mating systems and, more generally, for our understanding of the fundamental drivers of genetic diversity.

A step in the deep evolution of Alvinellidae (Annelida: Polychaeta): A phylogenomic comparative approach based on transcriptomes

The Alvinellidae are a family of worms that are endemic to deep-sea hydrothermal vents in the Pacific and Indian Oceans. These annelid worms, a sister group to the Ampharetidae, occupy a wide range of thermal habitats. The family includes the most thermotolerant marine animals described to date such as the Pompeii worm Alvinella pompejana, and other species living at much lower temperatures such as Paralvinella grasslei or Paralvinella pandorae. The phylogeny of this family has not been studied extensively. It is, however, a complex case where molecular phylogenies have given conflicting results, especially concerning the monophyletic or polyphyletic nature of the genus Paralvinella. We carried out a comprehensive study of the phylogeny of this family using the best molecular data currently available from RNAseq datasets, leading to several hundred orthologous transcripts for 11 of the 14 species currently described or in description. The results obtained by the two most popular phylogenetic inference models (using either gene concatenation with maximum likelihood, or a coalescent-based model from gene trees) were compared using a series of ampharetid and terebellid outgroups. Our study shows that the global phylogenetic signal favors the hypothesis of paraphyly for the Paralvinella genus, with P. pandorae being sister species of the other Alvinellidae. However, a high number of gene trees also supports the hypothesis of alternative trees in which the monophyly of the Paralvinella genus, as initially proposed by Desbruyères and Laubier, is valid with the species P. pandorae and Paralvinella unidentata being sister species. According to molecular dating, the radiation of the Alvinellidae was rapid and took place in a short period of time between 80 and 110 million years ago. This is reflected at the genomic scale by gene trees equally separated between different phylogenetic hypothesis, showing high rates of incomplete lineage sorting between the first lineages of the Alvinellidae and probable gene transfers. Although different genomic regions seem to have different phylogenetic stories in the early step of the alvinellid radiation, our study supports the view that the two P. pandorae species can be grouped into a separate genus (possibly Nautalvinella) and that the Miralvinella subgenus, defined by Desbruyères and Laubier, is not valid anymore.

Differential amplification and contraction of satellite DNAs in the distinct lineages of the beetle Euchroma gigantea

Satellite DNA (satDNA) consists of tandem repeat sequences that typically evolve rapidly through evolutionary mechanisms, including unequal crossover, transposition events, and others. The evolutionary history of Euchroma gigantea is marked by complex chromosomal evolution between lineages, making this species an interesting model for understanding satDNA evolution at intraspecies level. Therefore, our aim was to comprehend the potential contribution of satDNAs to the greater chromosomal differentiation of evolutionary lineages in E. gigantea by investigating the differential patterns of amplification and contraction of the repeats. To achieve this, we employed de novo identification of satDNA using RepeatExplorer and TAREAN, allowing the satellitome characterization between lineages. A total of 26 satDNA families were identified, ranging from 18 to 1101 nucleotides in length, with most families being shared between individuals/lineages, as predicted by the library hypothesis, except for the satDNA EgiSat21-168 that was absent for Northeast Lineage. The total satDNA content of the individuals was less than 11.2%, and it appeared to increase in two directions following the chromosomal evolution model. Thirteen satDNAs exhibited different patterns of amplification, and nine ones were contracted among individuals. Additionally, most repeats showed a divergence of about 10% for these satDNAs, indicating satellitome differentiation for each lineage/individual. This scenario suggests that the expansion of the satellitome occurred differentially among individuals/lineages of E. gigantea, with the contribution of various DNA turnover mechanisms after geographical isolation, and that they could be involved with karyotype evolution.

What are microsatellites and how to choose the best tool: a user-friendly review of SSR and 74 SSR mining tools

Microsatellites, also known as SSR or STR, are essential molecular markers in genomic research, playing crucial roles in genetic mapping, population genetics, and evolutionary studies. Their applications range from plant breeding to forensics, highlighting their diverse utility across disciplines. Despite their widespread use, traditional methods for SSR analysis are often laborious and time-consuming, requiring significant resources and expertise. To address these challenges, a variety of computational tools for SSR analysis have been developed, offering faster and more efficient alternatives to traditional methods. However, selecting the most appropriate tool can be daunting due to rapid technological advancements and the sheer number of options available. This study presents a comprehensive review and analysis of 74 SSR tools, aiming to provide researchers with a valuable resource for SSR analysis tool selection. The methodology employed includes thorough literature reviews, detailed tool comparisons, and in-depth analyses of tool functionality. By compiling and analyzing these tools, this study not only advances the field of genomic research but also contributes to the broader scientific community by facilitating informed decision-making in the selection of SSR analysis tools. Researchers seeking to understand SSRs and select the most appropriate tools for their projects will benefit from this comprehensive guide. Overall, this study enhances our understanding of SSR analysis tools, paving the way for more efficient and effective SSR research in various fields of study.

Removal of sequencing adapter contamination improves microbial genome databases

Advances in assembling microbial genomes have led to growth of reference genome databases, which have been transformative for applied and basic microbiome research. Here we show that published microbial genome databases from humans, mice, cows, pigs, fish, honeybees, and marine environments contain significant sequencing-adapter contamination that systematically reduces assembly accuracy and contiguousness. By removing the adapter-contaminated ends of contiguous sequences and reassembling MGnify reference genomes, we improve the quality of assemblies in these databases.

Detection and characterization of multidrug resistant Escherichia coli carrying virulence gene isolated from broilers in Bangladesh

BACKGROUND

The emergence and dissemination of multidrug resistant (MDR) bacteria pose a severe threat to public health by limiting clinical treatment and prophylactic options.

OBJECTIVES

This study investigates the prevalence of Escherichia coli in broilers, their phenotypic antimicrobial resistance (AMR) profiles and the presence of virulence-associated genes (VAGs) and antimicrobial resistance genes (ARGs) using polymerase chain reaction (PCR).

MATERIALS AND METHODS

A total of 216 pooled cloacal samples were collected from 1080 broilers across six districts of Bangladesh. Each pooled sample comprised randomly selected cloacal swabs from five birds per farm. E. coli isolates were identified using standard bacteriological approach, followed by biochemical assays and PCR. Antimicrobial susceptibility was assessed using the Kirby-Bauer disc diffusion method, and the presence of ARGs and VAGs was determined via PCR. Five selected isolates were partially sequenced for five VAGs using Sanger sequencing.

RESULTS

A total of 177 E. coli isolates (81.94%, 95% confidence interval: 76.24%-86.53%) were identified. The isolates showed the highest resistance to ampicillin (93.79%), followed by tetracycline (91.53%), erythromycin (89.27%) and ciprofloxacin (87%). Conversely, ceftriaxone (80.79%) showed highest susceptibility, followed by gentamicin (37.29%) and neomycin (31.07%). All isolates were MDR, with a multiple antibiotic resistance indexes were <0.3. A significant percentage (16.38%) of E. coli isolates were MDR to five antimicrobial classes and harboured blaTEM, sul1, ere (A), tetA, tetB and tetC genes. The highest prevalent ARGs were blaTEM (88.14%) followed by ere (A) (83.62%) and sul 1 (72.32%). The prevalence of VAGs was astA (56.50%), iucD (31.07%), iss (21.47%), irp2 (15.82%) and cva/cvi (3.39%), respectively.

CONCLUSIONS

This study highlights the presence of ARGs contributing to the development of MDR in E. coli carrying VAGs in broilers. Effective monitoring and surveillance of antimicrobial usage in poultry production systems are urgently required to prevent emergence and dissemination of AMR.

A review on the development of bacterial multi-epitope recombinant protein vaccines via reverse vaccinology

Bacterial vaccines play a crucial role in combating bacterial infectious diseases. Apart from the prevention of disease, bacterial vaccines also help to reduce the mortality rates in infected populations. Advancements in vaccine development technologies have addressed the constraints of traditional vaccine design, providing novel approaches for the development of next-generation vaccines. Advancements in reverse vaccinology, bioinformatics, and comparative proteomics have opened horizons in vaccine development. Specifically, the use of protein structural data in crafting multi-epitope vaccines (MEVs) to target pathogens has become an important research focus in vaccinology. In this review, we focused on describing the methodologies and tools for epitope vaccine development, along with recent progress in this field. Moreover, this article also discusses the challenges in epitope vaccine development, providing insights for the future development of bacterial multi-epitope genetically engineered vaccines.

Ketone body oxidation and susceptibility to ethyl acetoacetate in a novel hemolytic multidrug-resistant strain Leptospira interrogans KeTo originated from sewage water

Terrestrial and aquatic environments contaminated with animal urine may contribute to the transmission of Leptospira, a causative agent of leptospirosis in humans and wild/domesticated animals. Although enormous amounts of work have been done decoding the ecophysiology, the factors governing the cell growth and virulence in Leptospires derived from environmental samples still remain elusive. Here, we show oxidation of a wide array of organic acids including acetoacetate by a new strain of Leptospira interrogans designated as KeTo, isolated from a sewage sample originating from a wildlife enclosure located at Mangalore, India. We further demonstrate the susceptibility of KeTo to ethyl ester of acetoacetate (ethyl acetoacetate, EA). A 4.7 Mbp genome of KeTo shared the highest relatedness to pathogenic L. interrogans RGAT (99.3%), followed by L. kirschneri 3522CT (91.3%) and other related species of Leptospira (80.8‒74.3%), and harbored genes encoding acetoacetyl-CoA synthetase and acetoacetate decarboxylase respectively involved in the acetoacetate utilization and acetone formation. In line with this, strain KeTo oxidized acetoacetate when supplied as a sole carbon. Aqueous EA suppressed biofilm formation (p < 0.0001) of KeTo in basal Ellinghausen-McCullough-Johnson-Harris (EMJH) medium. Similarly, significant inhibition in the growth/biofilm of Leptospira was recorded in semisolid EMJH with/without blood supplementation when exposed to volatile EA. The extent of ketone body oxidation and susceptibility to EA was found to vary with strain as evident through the analysis of L. interrogans serogroup Australis sv. Australis strain Ballico and L. interrogans serogroup Icterohaemorrhagiae sv. Lai Like strain AF61. In conclusion, our study demonstrated the ketone body metabolic ability and susceptibility to an esterified derivative of a major ketone body in the tested strains of L. interrogans. Molecular aspects governing EA-driven growth inhibition warrant further investigations to develop optimal therapeutics for leptospirosis.

A Python program to merge Sanger sequences: an update

Gene cloning is an important step in investigating gene structure and function. To verify gene sequence, Sanger sequencing is used, which may produce several overlapping sequencing files that need to be merged before alignment to the target gene sequence is performed. Previously, we reported the Python program to Merge Sanger sequences (https://peerj.com/articles/11354/), which ran in command line and relied heavily on EMBOSS suite. In this updated version of the program, we have made several remarkable improvements. It provides a graphical user interface (GUI) written with tkinter, which is convenient and stable. It does not require users to rename the input sequences before performing merging. With regard to the implementation, the updated version utilizes Python function (Align.PairwiseAligner) to align adjacent sequences, which is more flexible (can adjust program parameter i.e., the number of first-time consecutive matching bases). The new version of the program makes merging Sanger sequences much more convenient and facilitates gene study.

Reexamining the Mycovirome of Botrytis spp

Botrytis species cause gray mold disease in more than 200 crops worldwide. To control this disease, chemical fungicides are usually applied. However, more sustainable control alternatives should be explored, such as the use of hypovirulent mycovirus-infected fungal strains. To determine the mycovirome of two Botrytis species, B. cinerea and B. prunorum, we reanalyzed RNA-Seq and small RNA-Seq data using different assembly programs and an updated viral database, aiming to identify new mycoviruses that were previously not described in the same dataset. New mycoviruses were identified, including those previously reported to infect or be associated with B. cinerea and Plasmopara viticola, such as Botrytis cinerea alpha-like virus 1 and Plasmopara viticola lesion-associated ourmia-like virus 80. Additionally, two novel narnaviruses, not previously identified infecting Botrytis species, have been characterized, tentatively named Botrytis cinerea narnavirus 1 and Botrytis narnavirus 1. The analysis of small RNAs suggested that all identified mycoviruses were targeted by the antiviral fungal mechanism, regardless of the viral genome type. In conclusion, the enlarged list of newly found viruses and the application of different bioinformatics approaches have enabled the identification of novel mycoviruses not previously described in Botrytis species, expanding the already extensive list.

Trait association and prediction through integrative k-mer analysis

Genome-wide association study (GWAS) with single nucleotide polymorphisms (SNPs) has been widely used to explore genetic controls of phenotypic traits. Alternatively, GWAS can use counts of substrings of length k from longer sequencing reads, k-mers, as genotyping data. Using maize cob and kernel color traits, we demonstrated that k-mer GWAS can effectively identify associated k-mers. Co-expression analysis of kernel color k-mers and genes directly found k-mers from known causal genes. Analyzing complex traits of kernel oil and leaf angle resulted in k-mers from both known and candidate genes. A gene encoding a MADS transcription factor was functionally validated by showing that ectopic expression of the gene led to less upright leaves. Evolution analysis revealed most k-mers positively correlated with kernel oil were strongly selected against in maize populations, while most k-mers for upright leaf angle were positively selected. In addition, genomic prediction of kernel oil, leaf angle, and flowering time using k-mer data resulted in a similarly high prediction accuracy to the standard SNP-based method. Collectively, we showed k-mer GWAS is a powerful approach for identifying trait-associated genetic elements. Further, our results demonstrated the bridging role of k-mers for data integration and functional gene discovery.

Streamlining of Simple Sequence Repeat Data Mining Methodologies and Pipelines for Crop Scanning

Genetic markers are powerful tools for understanding genetic diversity and the molecular basis of traits, ushering in a new era of molecular breeding in crops. Over the past 50 years, DNA markers have rapidly changed, moving from hybridization-based and second-generation-based to sequence-based markers. Simple sequence repeats (SSRs) are the ideal markers in plant breeding, and they have numerous desirable properties, including their repeatability, codominance, multi-allelic nature, and locus specificity. They can be generated from any species, which requires prior sequence knowledge. SSRs may serve as evolutionary tuning knobs, allowing for rapid identification and adaptation to new circumstances. The evaluations published thus far have mostly ignored SSR polymorphism and gene evolution due to a lack of data regarding the precise placements of SSRs on chromosomes. However, NGS technologies have made it possible to produce high-throughput SSRs for any species using massive volumes of genomic sequence data that can be generated fast and at a minimal cost. Though SNP markers are gradually replacing the erstwhile DNA marker systems, SSRs remain the markers of choice in orphan crops due to the lack of genomic resources at the reference level and their adaptability to resource-limited labor. Several bioinformatic approaches and tools have evolved to handle genomic sequences to identify SSRs and generate primers for genotyping applications in plant breeding projects. This paper includes the currently available methodologies for producing SSR markers, genomic resource databases, and computational tools/pipelines for SSR data mining and primer generation. This review aims to provide a 'one-stop shop' of information to help each new user carefully select tools for identifying and utilizing SSRs in genetic research and breeding programs.

A comprehensive atlas of nuclear sequences of mitochondrial origin (NUMT) inserted into the pig genome

BACKGROUND

The integration of nuclear mitochondrial DNA (mtDNA) into the mammalian genomes is an ongoing, yet rare evolutionary process that produces nuclear sequences of mitochondrial origin (NUMT). In this study, we identified and analysed NUMT inserted into the pig (Sus scrofa) genome and in the genomes of a few other Suinae species. First, we constructed a comparative distribution map of NUMT in the Sscrofa11.1 reference genome and in 22 other assembled S. scrofa genomes (from Asian and European pig breeds and populations), as well as the assembled genomes of the Visayan warty pig (Sus cebifrons) and warthog (Phacochoerus africanus). We then analysed a total of 485 whole genome sequencing datasets, from different breeds, populations, or Sus species, to discover polymorphic NUMT (inserted/deleted in the pig genome). The insertion age was inferred based on the presence or absence of orthologous NUMT in the genomes of different species, taking into account their evolutionary divergence. Additionally, the age of the NUMT was calculated based on sequence degradation compared to the authentic mtDNA sequence. We also validated a selected set of representative NUMT via PCR amplification.

RESULTS

We have constructed an atlas of 418 NUMT regions, 70 of which were not present in any assembled genomes. We identified ancient NUMT regions (older than 55 million years ago, Mya) and NUMT that appeared at different time points along the Suinae evolutionary lineage. We identified very recent polymorphic NUMT (private to S. scrofa, with < 1 Mya), and more ancient polymorphic NUMT (3.5-10 Mya) present in various Sus species. These latest polymorphic NUMT regions, which segregate in European and Asian pig breeds and populations, are likely the results of interspecies admixture within the Sus genus.

CONCLUSIONS

This study provided a first comprehensive analysis of NUMT present in the Sus scrofa genome, comparing them to NUMT found in other species within the order Cetartiodactyla. The NUMT-based evolutionary window that we reconstructed from NUMT integration ages could be useful to better understand the micro-evolutionary events that shaped the modern pig genome and enriched the genetic diversity of this species.

Identification and characterization of NHX gene family for their role under salt stress in Vigna mungo

In the current study, we have performed a comprehensive analysis of the Sodium Hydrogen Exchanger (NHX) gene family in Vigna mungo, and a total of 44 NHX genes were identified. A bimodal distribution based on domains, gene structure and phylogenetic analysis was evident. All intronpoor and intron-rich genes were clustered in clades I and II, respectively. Interestingly, all genes of subclade IIb were localized to vacuoles and possess only the NHX domain. The isoelectric point and trans-membrane domain analysis reflect the wide distribution of the NHX genes. Interestingly, Vm_NHX2 and Vm_NHX3 lacked trans-membrane domain but were found to interact with other NHX genes as well as vital salinity pathway genes, including calcium-mediated salt-responsive genes. The comparison of the mRNA sequences with that of V. marina, a halophytic species, reflects their independent evolution, majorly supporting the convergent evolution. The Ka/Ks ratio reflects the abundance of purifying selection supporting their conserved function during evolution. In our analysis, several abiotic stress and hormone-responsive elements and transcription factor binding sites were present in the promoter of the NHX genes. Further, the ion partitioning of a tolerant (K90) and a susceptible (K49) variety of V. mungo suggested that K90 managed the Na+/K+ ratio more affluently, which was also supported by profiling of superoxide radicals, hydrogen peroxide, phenol, peroxidase activity and superoxide dismutase activity. From the expression, we identified five candidate Vm_NHX genes, four of which, i.e. Vm_NHX16, Vm_NHX17, Vm_NHX29 and Vm_NHX33, were localized to the vacuolar and lysosomal membrane.

Genomics resources for the Rapa Nui (Eastern Island) spiny lobster Panulirus pascuensis (Crustacea: Decapoda: Achelata)

Background

The Easter Island spiny lobster Panulirus pascuensis (Reed, 1954) or ‘Ura’ in the Rapa Nui language, is a little known species native to the south eastern Pacific Ocean, distributed along the coasts of Easter Island, Pitcairn Island, and the Salas y Gómez Ridge. In Easter Island, P. pascuensis is the target of a small and profitable and probably overexploited fishery. In this study, we profited from a series of bioinformatic analyses to mine biological insight from low-pass short-read next generation sequencing datasets; we have estimated genome size and ploidy in P. pascuensis using a k-mer strategy, discovered, annotated, and quantified mobile elements in the nuclear genome, assembled the 45S rRNA nuclear DNA cassette and mitochondrial chromosome, and explored the phylogenetic position of P. pascuensis within the genus Panulirus using the signal retrieved from translated mitochondrial protein coding genes.

Results

K-mer analyses predicted P. pascuensis to be diploid with a haploid genome size ranging between 2.75 Gbp (with k-mer = 51) and 3.39 Gbp (with k-mer = 18). In P. pascuensis, repetitive elements comprise at least a half and a maximum of three fourths of the nuclear genome. Almost a third (64.94%) of the repetitive elements present in the studied nuclear genome were not assigned to any known family of transposable elements. Taking into consideration only annotated repetitive elements, the most abundant were classified as Long Interspersed Nuclear Elements (22.81%). Less common repetitive elements included Long Terminal Repeats (2.88%), Satellite DNA (2.66%), and DNA transposons (2.45%), among a few others. The 45S rRNA DNA cassette of P. pascuensis was partially assembled into two contigs. One contig, 2,226 bp long, encoded a partially assembled 5′ ETS the entire ssrDNA (1,861 bp), and a partial ITS1. A second contig, 6,714 bp long, encoded a partially assembled ITS1, the entire 5.8S rDNA (158 bp), the entire ITS2, the entire lsrDNA (4,938 bp), and a partial 3′ ETS (549 bp). The mitochondrial genome of P. pascuensis was 15,613 bp long and contained 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA genes (12S ribosomal RNA [rrnS] and 16S ribosomal RNA [rrnL]). A phylomitogenomic analysis based on PCGs retrieved Panulirus pascuensis as sister to a fully supported clade comprising P. cygnus and P. longipes.

Conclusion

We expect that the information generated in this study will guide the assembly of a chromosome-level nuclear genome for P. pascuensis in the near future. The newly assembled 45S rRNA nuclear DNA cassette and mitochondrial chromosome can support bioprospecting and biomonitoring of P. pascuensis using environmental DNA. The same elements can help to survey the public market place and detect mislabelling of this and other spiny lobsters. Overall, the genomic resources generated in this study will aid in supporting fisheries management and conservation strategies in this iconic spiny lobster that is likely experiencing overexploitation.

A Novel Dhillonvirus Phage against Escherichia coli Bearing a Unique Gene of Intergeneric Origin

Antibiotics resistance is expanding amongst pathogenic bacteria. Phage therapy is a revived concept for targeting bacteria with multiple antibiotics resistances. In the present study, we isolated and characterized a novel phage from hospital treatment plant input, using Escherichia coli (E. coli) as host bacterium. Phage lytic activity was detected by using soft agar assay. Whole-genome sequencing of the phage was performed by using Next-Generation Sequencing (NGS). Host range was determined using other species of bacteria and representative genogroups of E. coli. Whole-genome sequencing of the phage revealed that Escherichia phage Ioannina is a novel phage within the Dhillonvirus genus, but significantly diverged from other Dhillonviruses. Its genome is a 45,270 bp linear double-stranded DNA molecule that encodes 61 coding sequences (CDSs). The coding sequence of CDS28, a putative tail fiber protein, presented higher similarity to representatives of other phage families, signifying a possible recombination event. Escherichia phage Ioannina lytic activity was broad amongst the E. coli genogroups of clinical and environmental origin with multiple resistances. This phage may present in the future an important therapeutic tool against bacterial strains with multiple antibiotic resistances.

Phylogenomic analyses of all species of swordtail fishes (genus Xiphophorus) show that hybridization preceded speciation

Hybridization has been recognized to play important roles in evolution, however studies of the genetic consequence are still lagging behind in vertebrates due to the lack of appropriate experimental systems. Fish of the genus Xiphophorus are proposed to have evolved with multiple ancient and ongoing hybridization events. They have served as an informative research model in evolutionary biology and in biomedical research on human disease for more than a century. Here, we provide the complete genomic resource including annotations for all described 26 Xiphophorus species and three undescribed taxa and resolve all uncertain phylogenetic relationships. We investigate the molecular evolution of genes related to cancers such as melanoma and for the genetic control of puberty timing, focusing on genes that are predicted to be involved in pre-and postzygotic isolation and thus affect hybridization. We discovered dramatic size-variation of some gene families. These persisted despite reticulate evolution, rapid speciation and short divergence time. Finally, we clarify the hybridization history in the entire genus settling disputed hybridization history of two Southern swordtails. Our comparative genomic analyses revealed hybridization ancestries that are manifested in the mosaic fused genomes and show that hybridization often preceded speciation.

Bioprospecting of extremophilic perchlorate-reducing bacteria: report of promising Bacillus spp. isolated from sediments of the bay of Cartagena, Colombia

Three extremophile bacterial strains (BBCOL-009, BBCOL-014 and BBCOL-015), capable of degrading high concentrations of perchlorate at a range of pH (6.5 to 10.0), were isolated from Colombian Caribbean Coast sediments. Morphological features included Gram negative strain bacilli with sizes averaged of 1.75 × 0.95, 2.32 × 0.65 and 3.08 × 0.70 μm, respectively. The reported strains tolerate a wide range of pH (6.5 to 10.0); concentrations of NaCl (3.5 to 7.5% w/v) and KClO4- (250 to 10000 mg/L), reduction of KClO4- from 10 to 25%. LB broth with NaCl (3.5-30% w/v) and KClO4- (250-10000 mg/L) were used in independent trials to evaluate susceptibility to salinity and perchlorate, respectively. Isolates increased their biomass at 7.5 % (w/v) NaCl with optimal development at 3.5 % NaCl. Subsequently, ClO4- reduction was assessed using LB medium with 3.5% NaCl and 10000 mg/L ClO4-. BBCOL-009, BBCOL-014 and BBCOL-015 achieved 10%, 17%, and 25% reduction of ClO4-, respectively. The 16 S rRNA gene sequence grouped them as Bacillus flexus T6186-2, Bacillus marisflavi TF-11 (T), and Bacillus vietnamensis 15 - 1 (T) respectively, with < 97.5% homology. In addition, antimicrobial resistance to ertapenem, vancomycine, amoxicillin clavulanate, penicillin, and erythromycin was present in all the isolates, indicating their high adaptability to stressful environments. The isolated strains from marine sediments in Cartagena Bay, Colombia are suitable candidates to reduce perchlorate contamination in different environments. Although the primary focus of the study of perchlorate-reducing and resistant bacteria is in the ecological and agricultural realms, from an astrobiological perspective, perchlorate-resistant bacteria serve as models for astrobiological investigations.

The Virome of Cocoa Fermentation-Associated Microorganisms

Theobroma cacao plantations are of significant economic importance worldwide, primarily for chocolate production. During the harvest and processing of cocoa beans, they are subjected to fermentation either by microorganisms present in the environment (spontaneous fermentation) or the addition of starter cultures, with different strains directly contributing distinct flavor and color characteristics to the beans. In addition to fungi and bacteria, viruses are ubiquitous and can affect the quality of the fermentation process by infecting fermenting organisms, destabilizing microbial diversity, and consequently affecting fermentation quality. Therefore, in this study, we explored publicly available metatranscriptomic libraries of cocoa bean fermentation in Limon Province, Costa Rica, looking for viruses associated with fermenting microorganisms. Libraries were derived from the same sample at different time points: 7, 20, and 68 h of fermentation, corresponding to yeast- and lactic acid bacteria-driven phases. Using a comprehensive pipeline, we identified 68 viral sequences that could be assigned to 62 new viral species and 6 known viruses distributed among at least nine families, with particular abundance of elements from the Lenarviricota phylum. Interestingly, 44 of these sequences were specifically associated with ssRNA phages (Fiersviridae) and mostly fungi-infecting viral families (Botourmiaviridae, Narnaviridae, and Mitoviridae). Of note, viruses from those families show a complex evolutionary relationship, transitioning from infecting bacteria to infecting fungi. We also identified 10 and 3 viruses classified within the Totiviridae and Nodaviridae families, respectively. The quantification of the virus-derived RNAs shows a general pattern of decline, similar to the dynamic profile of some microorganism genera during the fermentation process. Unexpectedly, we identified narnavirus-related elements that showed similarity to segmented viral species. By exploring the molecular characteristics of these viral sequences and applying Hidden Markov Models, we were capable of associating these additional segments with a specific taxon. In summary, our study elucidates the complex virome associated with the microbial consortia engaged in cocoa bean fermentation that could contribute to organism/strain selection, altering metabolite production and, consequently, affecting the sensory characteristics of cocoa beans.

Secondary metabolite profile of Streptomyces spp. changes when grown with the sub-lethal concentration of silver nanoparticles: possible implication in novel compound discovery

The decline of new antibiotics and the emergence of multidrug resistance in pathogens necessitates a revisit of strategies used for lead compound discovery. This study proposes to induce the production of bioactive compounds with sub-lethal concentrations of silver nanoparticles (Ag-NPs). A total of Forty-two Actinobacteria isolates from four Saudi soil samples were grown with and without sub-lethal concentration of Ag-NPs (50 µg ml-1). The spent broth grown with Ag-NPs, or without Ag-NPs were screened for antimicrobial activity against four bacteria. Interestingly, out of 42 strains, broths of three strains grown with sub-lethal concentration of Ag-NPs exhibit antimicrobial activity against Staphylococcus aureus and Micrococcus luteus. Among these, two strains S4-4 and S4-21 identified as Streptomyces labedae and Streptomyces tirandamycinicus based on 16S rRNA gene sequence were selected for detailed study. The change in the secondary metabolites profile in the presence of Ag-NPs was evaluated using GC-MS and LC-MS analyses. Butanol extracts of spent broth grown with Ag-NPs exhibit strong antimicrobial activity against M. luteus and S. aureus. While the extracts of the controls with the same concentration of Ag-NPs do not show any activity. GC-analysis revealed a clear change in the secondary metabolite profile when grown with Ag-NPs. Similarly, the LC-MS patterns also differ significantly. Results of this study, strongly suggest that sub-lethal concentrations of Ag-NPs influence the production of secondary metabolites by Streptomyces. Besides, LC-MS results identified possible secondary metabolites, associated with oxidative stress and antimicrobial activities. This strategy can be used to possibly induce cryptic biosynthetic gene clusters for the discovery of new lead compounds.

A metagenome-derived artificial intelligence modeling framework advances the predictive diagnosis and interpretation of petroleum-polluted groundwater

Groundwater (GW) quality monitoring is vital for sustainable water resource management. The present study introduced a metagenome-derived machine learning (ML) model aimed at enhancing the predictive understanding and diagnostic interpretation of GW pollution associated with petroleum. In this framework, taxonomic and metabolic profiles derived from GW metagenomes were combined for use as the input dataset. By employing strategies that optimized data integration, model selection, and parameter tuning, we achieved a significant increase in diagnostic accuracy for petroleum-polluted GW. Explanatory artificial intelligence techniques identified petroleum degradation pathways and Rhodocyclaceae as strong predictors of a pollution diagnosis. Metagenomic analysis corroborated the presence of gene operons encoding aminobenzoate and xylene biodegradation within the de novo assembled genome of Rhodocyclaceae. Our genome-centric metagenomic analysis thus clarified the ecological interactions associated with microbiomes in breaking down petroleum contaminants, validating the ML-based diagnostic results. This metagenome-derived ML framework not only enhances the predictive diagnosis of petroleum pollution but also offers interpretable insights into the interaction between microbiomes and petroleum. The proposed ML framework demonstrates great promise for use as a science-based strategy for the on-site monitoring and remediation of GW pollution.