Search bioRxiv⌕ Search

Biology subjects

Singh, N. K.

Publications and source records attributed to Singh, N. K..

At least 19 recordsLinked to original sources

Predicting Fungal Contaminants for Space Missions Using Proteome-Wide Screening for Protein Orthologs

Fungal contamination poses a growing threat to spacecraft integrity, crew health, and planetary protection efforts. We describe a scalable and interpretable pipeline for identifying fungi with adaptation potential to spaceflight-associated stress conditions such as extreme temperatures, radiation levels, etc., and pathogenicity risks. Starting with proteins known to confer stress resistance, we identify orthologs across over fifteen hundred fungal species and evaluate their contamination potential via comparative proteome analysis. Our pipeline integrates proteins with known functional inference, cross-database proteome matching, and identity-based scoring to generate a ranked list of fungal species of concern. We apply this approach to detections from spacecraft assembly facilities, highlighting species with combined stress-tolerance and pathogenic potential. This study establishes a foundation for future AI-based risk assessments that can scale to orders of magnitude more fungal species, thus laying the foundation for systematic identification and assessment of fungal contaminants with potential adaptation and pathogenicity risks in spaceflight environments, thereby supporting contamination control strategies for future space missions. We also present an interactive visual online tool for researchers to trivially check the contamination potential of species in their own samples.

microbiology↗

Integration of QTL Mapping, Transcriptomics, and Genome Resequencing Identifies Yield-Associated Genes for Salt Stress in Rice

Salinity and sodicity stresses adversely affect rice growth and yield. To overcome yield losses, suitable tolerant rice cultivars can be developed through a marker-assisted breeding (MAB) program. In the present study, genomic regions associated with sodicity stress tolerance at the reproductive stage were identified using a high-density 50kSNP array in a recombinant inbred line (RIL) population derived from the contrasting rice genotypes CSR11 and MI48. A total of 50 QTLs were detected for various yield-related traits; further, 19 QTLs with [≥]15% of phenotypic variance were selected for integrated (omics) analysis. RNA sequencing of leaves and panicles at the reproductive stage under sodic stress conditions was employed to find differentially expressed genes. A total of 1368 and 1410 SNPs; 104 and 144 indels were found for MI48 and CSR11, respectively, within the QTL regions from resequencing. At chromosomes 1 and 6, colocalized QTLs (qPH1-1/qGP1-1 and qGP6-2/qSSI6-2) were discovered. Differentially expressed genes (DEGs) were mapped over the QTL regions selected, and SNP variations and indels were screened for colocalized QTLs. Potential candidate genes, namely Os-pGlcT1 (Os01g0133400), OsHKT2;1 (Os06g0701600) and OsHKT2;4 (Os06g0701700), OsANTH12 (Os06g0699800), and OsPTR2 (Os06g0706400), were identified as being responsible for glucose transport, ion homeostasis, pollen germination, and nitrogen use efficiency, respectively, under salt stress. Finally, our study provides important insights into the genes and potential mechanisms affecting grain yield under sodic stress in rice, which will contribute to the development of molecular markers for rice breeding programs.

plant biology↗

Duration of Initial Viremia Modulates Functional Properties of HIV-specific T Cell Receptors

Virus-specific CD8+ T cells are crucial in controlling chronic human viral infections such as HIV-1, but the effect of persistent antigen exposure on T cell repertoire formation is not well understood. In this study, we examined epitope-specific CD8+ T cell repertoires in people living with HIV-1, where duration of viremia following hyperacute infection was modulated by the time of initiation of continuous suppressive antiretroviral therapy (ART). After ART-induced undetectable viremia in persons expressing the same HLA class I allele, we analyzed the impact of early (n=6) versus delayed (n=6) ART initiation on the clonotypic composition, clonotypic cross-reactivity, functional avidity and memory differentiation profile of the HIV-specific T cell repertoire restricted by HLA-B*58:01. Using a panel of barcoded tetramers, we mapped T cell receptor (TCR) clonotypes specific for three dominant epitopes and their variants. Both groups exhibited polyclonal TCR repertoires with evidence of cross-reactivity, which was significantly enriched in donors with prolonged antigen exposure. Within this cohort, broadly cross-reactive clonotypes capable of recognizing all autologous variants were identified, but these were rare (<1%). Early ART initiation preserved repertoires characterized by higher-avidity TCRs and a relative enrichment of transitional memory CD8+ T cell subsets. These functional differences were not associated with differences in TRBV gene sharing, indicating that ART timing shapes repertoire quality and memory differentiation without altering TRBV gene bias. These findings demonstrate how antigen suppression dynamics differentially shape the breadth, functional sensitivity, and memory composition of the HIV-specific TCR repertoire, with implications for T cell-directed immunotherapies and HIV cure strategies. One Sentence SummaryThe duration of viral antigen exposure during early HIV infection shapes the functional quality, breadth, and memory composition of virus-specific CD8 T cell receptor repertoires. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=77 SRC="FIGDIR/small/702605v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@9a5a6dorg.highwire.dtl.DTLVardef@1a6bbdaorg.highwire.dtl.DTLVardef@17707e8org.highwire.dtl.DTLVardef@1a84d9e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

Plasmidome, resistome, and virulence-associated genes characterization of Acinetobacter johnsonii in NASA cleanrooms and a clinical setting.

Evidence shows persistence of non-spore-forming Acinetobacter johnsonii in high-stakes controlled and nutrient-limited environments. This study aims to explore the mechanisms underpinning such adaptability through a comprehensive genomic analysis of 22 isolates of A. johnsonii from NASAs Payload Hazardous Servicing Facility (PHSF) and one carbapenem-resistant strain (E154408A) from patient colonization in Ireland. Core-genome phylogeny revealed clustering of PHSF-originating isolates in a monophyletic clade divergent from the main species lineage. Species-wide virulence-associated genes and metabolic profiling indicated the unique presence in PHSF-originating isolates of two complete efflux pumps and of a conserved allantoin racemase, suggesting adaptability for multiple environmental stresses. Observed ubiquity of blaOXA in investigated genomes (n=112) and phenotypically-validated multidrug-resistant profile of E154408A strain highlight A. johnsoniis potential as antimicrobial resistance (AMR) reservoir. Plasmidome analysis suggested gain/loss events across the monophyletic population and potential AMR acquisition pathways. Genome-to-metagenome mapping identified genomic signatures of A. johnsonii in PHSF >10 years post initial isolation. ImportanceAcinetobacter johnsonii is increasingly recognized as an emerging human pathogen, with growing evidence of its ability to persist in controlled, high-stakes environments, posing risks as both persisting environmental contaminant and antimicrobial resistance (AMR) reservoir. Yet, gaps remain in our understanding of its AMR profile and the mechanisms that enable its enhanced environmental adaptability. This knowledge is necessary in contexts where biological cleanliness is a priority such as clinical settings and spacecraft assembly facilities cleanrooms, where contamination of hardware with terrestrial microorganisms is concerning. In this study, we aim to address some of key knowledge gaps by providing genomic insights into a rare multi-drug resistant clinical isolate and 22 NASA cleanroom isolates that persisted for over a decade in extremely clean conditions. Our findings will help evaluate the contamination risk of A. johnsonii in high-stakes environments and ultimately strengthen our ability to manage this microbial contaminant across terrestrial and extraterrestrial settings. HighlightsO_LICleanrooms-derived A. johnsonii genomes show favorable traits for increased adaptability C_LIO_LIGenomic signatures of A. johnsonii persisted in the cleanrooms for >10 years C_LIO_LIblaOXA is ubiquitously found in the genome of all A. johnsonii C_LIO_LIE154408A is the first patient colonization by carbapenem-resistant A. johnsonii in Europe C_LI

genomics↗

Chromosome-Scale, Telomere-to-Telomere Assembly of Winged Bean (Psophocarpus tetragonolobus (L.) DC.) Genome Reveals Lipid Biosynthetic Hotspots and Gene Family Dynamics

Winged bean (Psophocarpus tetragonolobus) is a nutritionally rich but cytologically and genomically underexplored legume with potential for climate-resilient agriculture. We report a telomere-to-telomere, chromosome-scale genome assembly ([~]697.69 Mb; N50 = 85.98 Mb; [~]98.25% of the cytometric estimate) of the cultivar AKWB1 using a combination of PacBio HiFi, Illumina, BioNano, and Hi-C technologies. Cytogenetics revealed a diploid karyotype (2n = 18) with exclusively metacentric chromosomes, establishing the first chromosomal ideotype map for the species. The high-quality assembly anchors 98.28% of bases to nine pseudochromosomes and includes 53,745 annotated protein-coding genes, with 97.6% BUSCO completeness. Repeat elements comprise [~]60% of the genome, dominated by LINEs, LTRs, and DNA transposons. KEGG and GO annotations reveal diverse biosynthetic capabilities across metabolic and stress-response pathways. Comparative genomics with nine legumes demonstrates conserved chromosomal synteny with Glycine max, absence of recent whole-genome duplication, and a contraction-dominated gene family history. Lipid metabolism analysis identified 750+ genes across 12 KEGG pathways, including fatty acid biosynthesis, elongation, and triacylglycerol assembly. Chromosomes 2, 3, and 5 showed enrichment of lipid biosynthetic loci, suggesting evolutionary hotspots. This reference genome positions P. tetragonolobus as a valuable model for studying genome evolution and engineering underutilized legumes for oil yield, protein enrichment, and climate adaptability.

genomics↗

UVA irradiation promotes ROS-mediated formation of the common deletion in mitochondrial DNA

Ultraviolet (UV) radiation from the sun causes adverse skin changes such as premature aging. UVA radiation is the primary factor for photoaging due to its deep penetration into the dermis, and UV-induced mitochondrial DNA (mtDNA) alterations, including deletions, contribute to photoaging and cellular dysfunction. The most frequent mtDNA rearrangement is the common deletion (CD), characterized by the loss of nearly one-third of the genome, 4,977 base pairs. UV radiation exposure leads to the formation of the CD, however, a distinct characterization of UV-induced CD and the underlying molecular mechanisms driving its initiation remains unexplored. In this study, we showed that increasing doses of UV radiation led to an increase in the CD in human skin fibroblasts. We found that UVA induce the formation of the CD by increasing the cellular reactive oxygen species (ROS) and oxidized bases content in the mtDNA. Preconditioning cells with antioxidants prevented the accumulation of the UVA-induced CD, suggesting that this mutational mechanism is ROS-dependent. In stark contrast, UVB did not alter cellular ROS levels but increased the formation of cyclobutane pyrimidine dimers (CPD), leading to CD generation though a ROS-independent mechanism. We corroborated our findings by using a 3D human full-thickness skin equivalent model, where we detected UVA-dependent CD formation in both the epidermal and dermal layers of the skin. By analyzing bulk RNA from UVA-exposed human skin fibroblasts by RNA-Seq, we found that UVA led to the upregulation of genes encoding mitochondrial DNA replication proteins and to the downregulation of genes involved genes encoding mtDNA repair factors. Taken together, our findings provide insight into how UVA and UVB differ in their detrimental effects on mtDNA, with UVA impacting mtDNA maintenance and transcription via a ROS-dependent mechanism. Our findings also established the mtDNA CD as a novel potential biomarker for monitoring UVA-induced oxidative stress and photoaging in skin cells in vitro and in vivo.

genomics↗

Alleviation of Drought Stress and Plant Growth Promotion in Mungbean through Rhizospheric Actinobacteria

Drought is a major cause for decreasing in crop yield and agricultural productivity around the Globe. The application of drought tolerance Actinobacteria to agroecosystem improves the growth and protect from water scarcity and they can be better alternative for natural farming and sustainable agriculture for aride and semi-aride regions. Herein, we isolated ten morphologically different actinobacteria from the rhizospheric soil of Datura and Khejri plants which are surviving in the nature without any special treatment provided. All the isolated bacteria were screened in-vitro for their drought tolerance capability for different time intervals against polyethylene glycol 8000 (PEG8000) with 5%, 10% and 10% concentration to media which produce moisture stress in which medium bacteria were growing. Among them best five bacterial isolates were selected and named RADM1 to RADM5 for further experimentation. Physiological characterizations were done through their ability to grow in different temperature, pH ranges and NaCl concentration supplemented with the 5% PEG8000. Morphology of the bacteria was Grams positive and mycelium producing same as typical Actinobacterial species and for biochemical diversity stains were able to IMVIC test and carbohydrate utilization through IMVIC test. Enzymatic observations of isolates were resulted positive for nitrate reduction, catalase production and negative for starch hydrolysis. PCR amplification and 16S rRNA gene sequencing in BlastN found maximum similarity of three species with Streptomyces clavuligerus and two species with Rhodococcus erythropolis and submitted to NCBI gene bank database with accession number PQ114139 (RADM1), PQ120343 (RADM2), PQ114109 (RADM3), PQ120390 (RADM4), PQ039766 (RADM5). In pot trial of mungbean, all the isolates showed better performance in bacterial treatments with an average increase in physiological parameters like, seedlings shoot length (52.70% and 9.62%), root length (35.63% and 17.25%), fresh weight (42.8% and 13.76%) dry weight (45.25% and 21.24%) in compared to uninoculated induced drought and watered treatments. Stress features of seedlings revealed significant increase in proline and chlorophyll contents whereas decrease in MDA contents than the untreated plants which indicates actinobacteria reduced water scarcity and damage of plant membrane. IMPORTANCERhizosphere of plant contains diversity of microbes with different abilities to support the plant growth. The role of plant growth promoting bacteria in soil presented and their association with plant can be the one reason for survive of the plant against the abiotic stress conditions like drought, salinity, temperature or pH. The actinobacteria found in the rhizosphere have evolved multiple strategies to assist plants in managing the adverse effects of drought. These strategies may include alterations in phytohormones, which play a vital role in enabling plants to withstand environmental stresses, modifications to root structures, accumulation of osmolytes, enhancements in the plants antioxidant defense mechanisms, synthesis of exopolysaccharides, and the identification of particular genes that support plant growth and improve drought resilience. These actinobacteria as bioinoculant can be the better alternative for the chemical fertilizers use and protect from the water scarcity.

microbiology↗

PNPLA3 I148M Reduces Hepatic Triacylglycerol Secretion and Mitigates Left Ventricular Diastolic Dysfunction in MASH Diet Mice

Cardiovascular disease (CVD) is a leading cause of mortality among individuals with metabolic dysfunction-associated steatotic liver disease (MASLD). Paradoxically, the strongest genetic risk factor for MASLD, PNPLA3-I148M, is associated with a reduced risk of CVD. The mechanisms for how PNPLA3-I148M causes MASLD and preserves cardiac health are not well understood. To further investigate cardioprotective effects of PNPLA3-I148M we expressed human WT-PNPLA3, PNPLA3-I148M or a GFP control in the livers of PNPLA3-/- mice. In agreement with prior investigations, mice expressing PNPLA3-I148M displayed greater hepatic neutral lipid accumulation on chow and a Metabolic Dysfunction-Associated Steatohepatitis (MASH) promoting diet. Changes in hepatosteatosis between the groups was not due to alterations in whole body metabolic parameters, although WT-PNPLA3 promoted greater glucose intolerance on a MASH diet. Echocardiography revealed that hearts from PNPLA3-WT mice had changes in left ventricular mass and thickness following 16-weeks of MASH, but not chow diet, which was not seen in the GFP or PNPLA3-I148M groups. Moreover, PNPLA3-WT and GFP mice had reduced E/A ratios (diastolic function), post MASH diet, which was not detected in PNPLA3-I148M mice. In addition, PNPLA3-I148M reduced hepatic secretion of TAGs under a MASH, but not chow diet. The expression of PNPLA3-I148M modified the liver lipidome, while minimal effects were observed in the heart. No differences in atherosclerotic plaque formation were observed following 24 weeks of MASH diet. These findings indicate that hepatic PNPLA3-I148M promotes hepatosteatosis yet protects against diet induced cardiac remodeling and diastolic dysfunction primarily through reductions in hepatic TAG secretion.

physiology↗

Assembly, Annotation, and Comparative Analysis of the Mitochondrial Genome of Winged Bean (Psophocarpus tetragonolobus): Insights into Evolutionary Adaptation and Codon Usage Bias

The winged bean (Psophocarpus tetragonolobus) is an underutilized, nutritionally dense legume with significant agricultural potential due to its adaptability to tropical environments and nitrogen-fixing capabilities. This study presents the assembly, annotation, and comparative analysis of its complete mitochondrial genome, spanning 366,925 bp. The genome comprises 64 genes, including 38 protein-coding genes, 12 tRNA genes, and 6 rRNA genes. Codon usage analysis revealed moderate bias in mitochondrial genes, primarily shaped by mutational pressures, while tRNA gene content aligns with codon preferences, optimizing translational efficiency. Phylogenetic analysis placed P. tetragonolobus within the Phaseoleae tribe, clustering closely with Glycine max and Vigna radiata, while synteny analysis highlighted high genomic conservation with related legumes. Ka/Ks ratio analysis underscored strong purifying selection in core mitochondrial genes, reflecting functional constraints essential for energy metabolism. Comparative analyses of mitochondrial and chloroplast genomes revealed distinct evolutionary pressures, with chloroplast genes exhibiting more significant variability influenced by functional roles in photosynthesis. These findings provide valuable insights into the evolution and adaptation of P. tetragonolobus, establishing a foundation for its potential application in sustainable agriculture and crop improvement programs.

genomics↗

Comprehensive benchmarking of tools for nanopore-based detection of DNA methylation

Long read sequencing technologies such as Oxford Nanopore (ONT) offer direct, simultaneous detection of DNA base modifications. The recent migration of ONT to the upgraded R10 chemistry has spurred the development of diverse methylation detection models. However, their performance and accuracy remain unclear. Here, leveraging diverse bacterial, plant, and mammalian datasets, we systematically evaluate the current landscape of tools and models for studying DNA methylation using nanopore sequencing. Our results demonstrate that the older models remain the best choice for studying CpG methylation. We note substantial improvement of newer tools in identifying 5-methylcytosine in non-CG contexts, 6-methyladenine, and 4-methylcytosine. We highlight the sensitivity of various tools to confounding methylation nearby. We also assess the computational performance of various tools, and effects of sequencing depth, methylation abundance, read quality, and basecalling mode. Our reusable pipelines and fully open access datasets provide a framework of resources to empower future benchmarking efforts. Our work thus details the strengths and limitations of the state-of-the-art methylation models and outlines practical guidelines for researchers using nanopore sequencing to study DNA modifications.

genomics↗

Click-chemistry-aided quantitation and sequencing of oxidized guanines and apurinic sites uncovers their transcription-linked strand bias in human cells

DNA modifications drive aging, neurodegeneration, carcinogenesis, and chemotherapy drug action. To understand the functional genomic roles of DNA modifications, it is critical to accurately map their diverse chemical forms with single-nucleotide precision in complex genomes, but it remains challenging. Click-code-seq is a click-chemistry-aided single-nucleotide-resolution strategy for guanine-oxidation mapping, used in yeast DNA but having poor applicability to human genomes. Here, we upgraded click-code-seq to enable its first application for sequencing DNA oxidation and depurination in human genomes. For this, we developed a companion fluorescence assay, click-fluoro-quant, to rapidly quantify different common DNA modifications, and devised novel adapters to minimize false modification detection and assess modification frequency in cell populations. We uncovered that endogenous DNA oxidation in a human cell line has a highly similar pattern to cancer mutational signatures associated with reactive oxygen species. We established that the DNA-alkylating chemotherapy drug irofulven preferentially induces depurination in ApA dimers and promoter regions. Intriguingly, we revealed that oxidized guanines and apurinic sites, both irofulven-induced and endogenous, are depleted in gene transcribed strands, and the strand bias widens with increasing gene expression. This work substantially advances click-code-seq for deciphering the impacts of key modifications in human DNA on cellular physiology and toxicological responses.

genomics↗

NEMO: Improved and accurate models for identification of 6mA using Nanopore sequencing

DNA methylation plays a key role in epigenetic regulation across lifeforms. Nanopore sequencing enables direct detection of base modifications. While multiple tools are currently available for studying 5-methylcytosine (5mC), there is a paucity of models that can detect 6-methyladenine (6mA) from raw nanopore data. Leveraging the motif-driven nature of bacterial methylation systems, we generated 6mA identification models that vastly surpass the accuracy of the current best model. Our work enables the study of 6mA at a single-base resolution in new as well as existing nanopore datasets.

genomics↗

Spaceflight alters host-gut microbiota interactions

The rodent habitat on the International Space Station has provided crucial insights into the impact of spaceflight on mammals, including observation of symptoms characteristic of liver disease, insulin resistance, osteopenia and myopathy. Although these physiological responses can involve the microbiome when observed on Earth, changes in host-microbiota interactions during spaceflight are still being elucidated. Here, NASA GeneLab multiomic data from the Rodent Research 6 mission are used to determine changes to gut microbiota and murine host colon and liver gene expression after 29 and 56-days of spaceflight. Using hybrid amplicon and whole metagenome sequencing analysis, significant spaceflight-associated alterations to 42 microbiome species were identified. These included relative reductions of bacteria associated with bile acid and butyrate metabolism, such as Extibacter muris and Dysosmobacter welbionis. Functional prediction suggested over-representation of fatty acid and bile acid metabolism, extracellular matrix interactions, and antibiotic resistance genes within the gut microbiome, while host intestinal and hepatic gene expression described corresponding changes to host bile acid and energy metabolism, and immune suppression from spaceflight. Taken together, these changes imply that interactions at the host-gut microbiome interface contribute to spaceflight pathology and highlight how these interactions might critically influence human health and the feasibility of long-duration spaceflight.

genomics↗

Adaptation to space conditions of novel bacterial species isolated from the International Space Station revealed by functional gene annotations and comparative genome analysis

BackgroundThe extreme environment of the International Space Station (ISS) puts selective pressure on microorganisms unintentionally introduced during its 20+ years of service as a low-orbit science platform and human habitat. Such pressure leads to the development of new features not found in the Earth-bound relatives, which enable them to adapt to unfavorable conditions. ResultsIn this study, we generated the functional annotation of the genomes of five newly identified species of Gram-positive bacteria, four of which are non-spore-forming and one spore-forming, all isolated from the ISS. Using a deep-learning based tool - deepFRI - we were able to functionally annotate close to 100% of protein-coding genes in all studied species, overcoming other annotation tools. Our comparative genomic analysis highlights common characteristics across all five species and specific genetic traits that appear unique to these ISS microorganisms. Proteome analysis mirrored these genomic patterns, revealing similar traits. The collective annotations suggest adaptations to life in space, including the management of hypoosmotic stress related to microgravity via mechanosensitive channel proteins, increased DNA repair activity to counteract heightened radiation exposure, and the presence of mobile genetic elements enhancing metabolism. In addition, our findings suggest the evolution of certain genetic traits indicative of potential pathogenic capabilities, such as small molecule and peptide synthesis and ATP-dependent transporters. These traits, exclusive to the ISS microorganisms, further substantiate previous reports explaining why microbes exposed to space conditions demonstrate enhanced antibiotic resistance and pathogenicity. ConclusionOur findings indicate that the microorganisms isolated from ISS we studied have adapted to life in space. Evidence such as mechanosensitive channel proteins, increased DNA repair activity, as well as metallopeptidases and novel S-layer oxidoreductases suggest a convergent adaptation among these diverse microorganisms, potentially complementing one another within the context of the microbiome. The common genes that facilitate adaptation to the ISS environment may enable bioproduction of essential biomolecules need during future space missions, or serve as potential drug targets, if these microorganisms pose health risks.

bioinformatics↗

Genomic, Functional, and Metabolic Enhancements in Multidrug-Resistant Enterobacter bugandensis Facilitating its Persistence and Succession in the International Space Station

BackgroundThe International Space Station (ISS) stands as a testament to human achievement in space exploration. Despite its highly controlled environment, characterised by microgravity, increased CO2 levels, and elevated solar radiation, microorganisms occupy a unique niche. These microbial inhabitants play a significant role in influencing the health and well-being of astronauts on board. One microorganism of particular interest in our study is Enterobacter bugandensis, primarily found in clinical specimens including the human gastrointestinal tract, and also reported to possess pathogenic traits, leading to a plethora of infections. ResultsDistinct from their Earth counterparts, ISS E. bugandensis strains have exhibited resistance mechanisms that categorize them within the ESKAPE pathogen group, a collection of pathogens recognized for their formidable resistance to antimicrobial treatments. During the two-year Microbial Tracking 1 mission, 12 strains of multidrug resistant E. bugandensis were isolated from various locations within the ISS. We have carried out a comprehensive study to understand the genomic intricacies of ISS-derived E. bugandensis in comparison to terrestrial strains, with a keen focus on those associated with clinical infections. We unravel the evolutionary trajectories of pivotal genes, especially those contributing to functional adaptations and potential antimicrobial resistance. A hypothesis central to our study was that the singular nature of the stresses of the space environment, distinct from any on Earth, could be driving these genomic adaptations. Extending our investigation, we meticulously mapped the prevalence and distribution of E. bugandensis across the ISS over time. This temporal analysis provided insights into the persistence, succession, and potential patterns of colonization of E. bugandensis in space. Furthermore, by leveraging advanced analytical techniques, including metabolic modelling, we delved into the coexisting microbial communities alongside E. bugandensis in the ISS across multiple missions and spatial locations. This exploration revealed intricate microbial interactions, offering a window into the microbial ecosystem dynamics within the ISS. ConclusionsOur comprehensive analysis illuminated not only the ways these interactions sculpt microbial diversity but also the factors that might contribute to the potential dominance and succession of E. bugandensis within the ISS environment. The implications of these findings are two-fold. Firstly, they shed light on microbial behavior, adaptation, and evolution in extreme, isolated environments. Secondly, they underscore the need for robust preventive measures, ensuring the health and safety of astronauts by mitigating risks associated with potential pathogenic threats.

systems biology↗

Pharmacology of Berberine and its Metabolites, is it the natures Ozempic or Imatinib?

BackgroundBerberine, which is a naturally occurring alkaloid is widely explored for several health benefits including for weight management and metabolic disorders. The major pharmacological action of berberine is reported to be by activation of AMP-activated protein kinase, while its other clinical outcomes are devoid of clear mechanism of action/s. Hence in this study a detailed pharmacology of berberine and its two major metabolites (berberrubine, and jatrorrhizine) in humans was evaluated using well established Insilco tools. Materials and MethodsThe targets of berberine and its metabolites were identified in SwissTargetPrediction server and their affinity was assed using AutoDock vina 1.2.0. The binding pockets of the highest ligand receptor combinations was assessed using the PrankWeb: Ligand Binding Site Prediction tool. ResultsKinases, enzymes and family A GPCRs were identified as the top three target category of berberine and its metabolites. ROCK2, PIK3CD, KCNMA1, CSF1R and KIT were observed to be the high affinity targets of berberine and its metabolites with affinity values of <4 uM. The affinity of berberine and its metabolites against all AMPKs and lipid/glucose regulator targets (LDLR, DDP4 and PCSK9) were > 10 uM. The IC50 value of berberine and its metabolites against ROCK2 was the least (<1 uM), while their other high affinity targets (PIK3CD, KCNMA1, CSF1R and KIT) showed IC50 values < 5 uM. ConclusionThe diverse range of protein targets and the observed novel high affinity targets (ROCK2, PIK3CD, KCNMA1, CSF1R and KIT) offer valuable insights into the potential mechanisms of action and therapeutic effects of berberine and its metabolites in various disease conditions, which warrants validation in suitable efficacy analysis studies.

pharmacology and toxicology↗

Genomic analysis reveals the presence of emerging pathogenic Klebsiella lineages aboard the International Space Station.

Klebsiella species, including Klebsiella pneumoniae, Klebsiella aerogenes, and Klebsiella quasipneumoniae, are opportunistic pathogens that are known to cause infections in humans. Hypervirulent Klebsiella pneumoniae (hvKP) is a subgroup of K. pneumoniae that has gained attention due to its global dissemination and its ability to cause invasive infections in community settings amongst immunocompetent individuals as well as its increasing levels of antibiotic resistance. Our study reports the first complete genotypic analysis including mobile genetic elements (MGEs) of Klebsiella isolates from the International Space Station (ISS). The genomes of K. pneumoniae, K. aerogenes, and K. quasipneumoniae provided valuable insights into their antimicrobial resistance, virulence, thermotolerance, disinfectant resistance, and MGEs. All isolates belonged to emerging lineages with pathogenic potential, with K. quasipneumoniae ST138 presenting spatial and temporal persistence aboard the ISS, possibly due to its genotypic profile encoding for numerous resistance genes to disinfectants and heavy metals. We also report on the isolation of a yersiniabactin encoding K. pneumoniae, belonging to the emerging high-risk ST101 clone, aboard the ISS. Potential dissemination of hvKp strains on ISS could pose a putative risk to the immunocompromised crew. The presence of MGEs containing virulent loci could facilitate horizontal gene transfer to other benign microorganisms on the ISS, potentially increasing their virulence. In addition, genetic divergence from their respective lineages for some Klebsiella genomes was predicted and hypothesized to be due to the unique spaceflight environmental pressures. These findings highlight the importance of monitoring problematic microbial communities in space to understand their surviving abilities and potential impact on human health. ImportanceThe International Space Station (ISS) is a unique hermetically sealed environment that poses environmental pressures not encountered on Earth, including microgravity and radiation While the adaptability of bacteria during spaceflight is not fully understood, recent research has suggested that it may be species and even clone specific. Given the spaceflight-induced suppression of the human immune system, it is essential to understand the genomics of potential human pathogens in spaceflight. Such understanding could provide valuable insights into species and lineages of medical astromicrobiological importance. Here, we used hybrid assembly approaches and comparative genomics to provide the first comprehensive genomic characterisation of 10 Klebsiella isolates retrieved from the ISS. Our findings revealed that K. quasipneumoniae ST138 exhibits spatial and temporal persistence aboard the ISS, with evidence of genomic divergence from the ST138 lineage on Earth. Additionally, we characterized plasmids from Klebsiella species of ISS origin, which encoded disinfectant and thermoresistance genes suggesting that these might aid adaptability. Furthermore, we identified an MGE containing a hypervirulence-associated locus belonging to a Klebsiella pneumoniae isolate of the "high risk" ST101 clone. Our work provides valuable insights into the adaptability and persistence of Klebsiella species during spaceflight, highlighting the importance of understanding the behaviour of potential pathogenic bacteria in space.

microbiology↗

Decoupled neoantigen cross-presentation in tumors with high intratumor heterogeneity reduces dendritic cell activation to limit anti-tumor immunity

Cancer immunotherapies, in particular checkpoint blockade immunotherapy (CBT), can induce control of cancer growth, with a fraction of patients experiencing durable responses. However, the majority of patients currently do not respond to CBT and the molecular determinants of resistance have not been fully elucidated. Mounting clinical evidence suggests that the clonal status of neoantigens (NeoAg) impacts the anti-tumor T cell response. High intratumor heterogeneity (ITH), where the majority of NeoAgs are expressed subclonally, is correlated with poor clinical response to CBT and poor infiltration with tumor-reactive T cells. However, the mechanism by which ITH blunts tumor-reactive T cells is unclear. We developed a transplantable murine lung cancer model to characterize the immune response against a defined set of NeoAgs expressed either clonally or subclonally to model low or high ITH, respectively. Here we show that clonal expression of a weakly immunogenic NeoAg with a relatively strong NeoAg increased the immunogenicity of tumors with low but not high ITH. Mechanistically we determined that clonal NeoAg expression allowed cross-presenting dendritic cells to acquire and present both NeoAgs. Dual NeoAg presentation by dendritic cells was associated with a more mature DC phenotype and a higher stimulatory capacity. These data suggest that clonal NeoAg expression can induce more potent anti-tumor responses due to more stimulatory dendritic cell: T cell interactions. Therapeutic vaccination targeting subclonally expressed NeoAgs could be used to boost anti-tumor T cell responses.

immunology↗