NCBI Reference Sequence (RefSeq): a curated non-redundant sequence database of genomes, transcripts and proteins

Lake microbiome and trophy fluctuations of the ancient hemp rettery

Lake sediments not only store the long-term ecological information including pollen and microfossils but are also a source of sedimentary DNA (sedDNA). Here, by the combination of traditional multi-proxy paleolimnological methods with the whole-metagenome shotgun-sequencing of sedDNA we were able to paint a comprehensive picture of the fluctuations in trophy and bacterial diversity and metabolism of a small temperate lake in response to hemp retting, across the past 2000 years. Hemp retting (HR), a key step in hemp fibre production, was historically carried out in freshwater reservoirs and had a negative impact on the lake ecosystems. In Lake Slone, we identified two HR events, during the late stage of the Roman and Early Medieval periods and correlated these to the increased trophy and imbalanced lake microbiome. The metagenomic analyses showed a higher abundance of Chloroflexi, Planctomycetes and Bacteroidetes and a functional shift towards anaerobic metabolism, including degradation of complex biopolymers such as pectin and cellulose, during HR episodes. The lake eutrophication during HR was linked to the allochthonous, rather than autochthonous carbon supply—hemp straws. We also showed that the identification of HR based on the palynological analysis of hemp pollen may be inconclusive and we suggest the employment of the fibre count analysis as an additional and independent proxy.

Fatal Infection in an Alpaca (Vicugna pacos) Caused by Pathogenic Rhodococcus equi

Simple Summary

Serious consequences of septicemic bacterial infections include the formation of purulent and pyogranulomatous inflammation resulting in abscesses in inner organs. Different bacteria are known to cause these infections in livestock. In this study, we report in detail on a case of a fatal Rhodococcus (R.) equi infection in an alpaca (Vicugna pacos), to our knowledge, for the first time. R. equi is a member of the actinomycetes, a bacterial group known to contain several pathogenic bacteria. R. equi primarily affects equine foals and other domestic animals, but also humans, which renders this bacterium a zoonotic agent. The rhodococcal infection of the alpaca reported herein caused septicemia, resulting in emaciation and severe lesions in the lungs and heart. The onset of infection was presumably caused by aspiration pneumonia, resulting in abscesses exclusively in the lungs. The R. equi isolate proved to be pathogenic, based on the virulence gene vapA encoding the virulence-associated protein A. Antibiotic susceptibility testing revealed a susceptibility to doxycycline, erythromycin, gentamycin, neomycin, rifampicin, trimethoprim/sulfamethoxazole, tetracycline and vancomycin. This report of an R. equi infection in an alpaca makes clear that we still have knowledge gaps about bacterial infectious diseases in alpacas and potential zoonotic impacts. Therefore, the determination of pathogenic, zoonotic bacteria in alpacas is essential for treatment and preventive measures with respect to sustaining the health, welfare and productivity of this camelid species.

Abstract

Rhodococcus (R.) equi is a pathogen primarily known for infections in equine foals, but is also present in numerous livestock species including New World camelids. Moreover, R. equi is considered an emerging zoonotic pathogen. In this report, we describe in detail a fatal rhodococcal infection in an alpaca (Vicugna pacos), to our best knowledge, for the first time. The alpaca died due to a septicemic course of an R. equi infection resulting in emaciation and severe lesions including pyogranulomas in the lungs and pericardial effusion. The onset of the infection was presumably caused by aspiration pneumonia. R. equi could be isolated from the pyogranulomas in the lung and unequivocally identified by MALDI-TOF MS analysis and partial sequencing of the 16S rRNA gene, the 16S-23S internal transcribed spacer (ITS) region and the rpoB gene. The isolate proved to possess the vapA gene in accordance with tested isolates originating from the lungs of infected horses. The R. equi isolates revealed low minimal inhibitory concentrations (MIC values) for doxycycline, erythromycin, gentamycin, neomycin, rifampicin, trimethoprim/sulfamethoxazole, tetracycline and vancomycin in antibiotic susceptibility testing. Investigations on the cause of bacterial, especially fatal, septicemic infections in alpacas are essential for adequately addressing the requirements for health and welfare issues of this New World camelid species. Furthermore, the zoonotic potential of R. equi has to be considered with regard to the One Health approach.

Identification of Therapeutic Targets in an Emerging Gastrointestinal Pathogen Campylobacter ureolyticus and Possible Intervention through Natural Products

Campylobacter ureolyticus is a Gram-negative, anaerobic, non-spore-forming bacteria that causes gastrointestinal infections. Being the most prevalent cause of bacterial enteritis globally, infection by this bacterium is linked with significant morbidity and mortality in children and immunocompromised patients. No information on pan-therapeutic drug targets for this species is available yet. In the current study, a pan-genome analysis was performed on 13 strains of C. ureolyticus to prioritize potent drug targets from the identified core genome. In total, 26 druggable proteins were identified using subtractive genomics. To the best of the authors’ knowledge, this is the first report on the mining of drug targets in C. ureolyticus. UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) was selected as a promiscuous pharmacological target for virtual screening of two bacterial-derived natural product libraries, i.e., postbiotics (n = 78) and streptomycin (n = 737) compounds. LpxC inhibitors from the ZINC database (n = 142 compounds) were also studied with reference to LpxC of C. ureolyticus. The top three docked compounds from each library (including ZINC26844580, ZINC13474902, ZINC13474878, Notoginsenoside St-4, Asiaticoside F, Paraherquamide E, Phytoene, Lycopene, and Sparsomycin) were selected based on their binding energies and validated using molecular dynamics simulations. To help identify potential risks associated with the selected compounds, ADMET profiling was also performed and most of the compounds were considered safe. Our findings may serve as baseline information for laboratory studies leading to the discovery of drugs for use against C. ureolyticus infections.

APOBEC3A regulates transcription from interferon-stimulated response elements

APOBEC3A (A3A) is a cytidine deaminase that inactivates a variety of viruses through introduction of lethal mutations to the viral genome. Additionally, A3A can suppress HIV-1 transcription in a deaminase-independent manner by binding to the long terminal repeat of proviral HIV-1. However, it is unknown whether A3A targets additional host genomic loci for repression. In this study, we found that A3A suppresses gene expression by binding TTTC doublets that are in close proximity to each other. However, one TTTC motif is sufficient for A3A binding. Because TTTC doublets are present in interferon (IFN)-stimulated response elements (ISRE), we hypothesized that A3A may impact IFN-stimulated gene (ISG) expression. After scanning the human genome for TTTC doublet occurrences, we discovered that these motifs are enriched in the proximal promoters of genes associated with antiviral responses and type I IFN (IFN-I) signaling. As a proof of principle, we examined whether A3A can impact ISG15 expression. We found that A3A binding to the ISRE inhibits phosphorylated STAT-1 binding and suppresses ISG15 induction in response to IFN-I treatment. Consistent with these data, our RNA-sequencing analyses indicate that A3A loss results in increased IFN-I–dependent induction of several ISGs. This study revealed that A3A plays an unexpected role in ISG regulation and suggests that A3A contributes to a negative feedback loop during IFN signaling.

Comparative Genomics Revealed Wide Intra-Species Genetic Heterogeneity and Lineage-Specific Genes of Akkermansia muciniphila

Akkermansia muciniphila has potential as a next-generation probiotic, but few previous studies attempted to analyze its intraspecies population diversity. In this study, we performed a comparative genomic analysis of 112 filtered genomes from the NCBI database. The populations formed three clades (A-C) on the phylogenetic tree, suggesting the existence of three genetic lineages though clades B and C were phylogenetically closer than clade A. The three clades also showed geographic-based clustering, different genetic characteristics, and clade-specific genes. Two putative functional genes (RecD2 and xerD) were specific to clade C due to genomic islands. These lineage-specific genes might be associated with differences in genomic features (number of phages/genomic islands, pan-core genome, recombination rate, genetic diversity) between genetic lineages. The carbohydrate utilization gene profile (particularly for glycolytic hydrolases and carbohydrate esterases) also varied between clades, suggesting different carbohydrate metabolism potential/requirements between genetic lineages. Our findings provide important implications for future research on A. muciniphila.

IMPORTANCEAkkermansia muciniphila has been widely accepted as part of the next generation of probiotics. However, most current studies on A. muciniphila have focused on the application of type strain BAA835^T in the treatment of diseases, while few studies have reported on the genomic specificity, population structure, and functional characteristics of A. muciniphila species. By comparing the genomes of 112 strains from NCBI which met the quality control conditions, we found that the A. muciniphila population could be divided into three main clades (clades A to C) and presented a certain regional aggregation. There are significant differences among the three clades in their genetic characteristics and functional genes (the type strain BAA835^T was located in clade A), especially in genes related to carbohydrate metabolism. It should be mentioned that probiotics should be a concept at the strain level rather than at the gut species level, so the probiotic properties of A. muciniphila need to be carefully interpreted.

Comparative Analysis and Data Provenance for 1,113 Bacterial Genome Assemblies

The availability of public genomics data has become essential for modern life sciences research, yet the quality, traceability, and curation of these data have significant impacts on a broad range of microbial genomics research. While microbial genome databases such as NCBI’s RefSeq database leverage the scalability of crowd sourcing for growth, genomics data provenance and authenticity of the source materials used to produce data are not strict requirements. Here, we describe the de novo assembly of 1,113 bacterial genome references produced from authenticated materials sourced from the American Type Culture Collection (ATCC), each with full genomics data provenance relating to bioinformatics methods, quality control, and passage history. Comparative genomics analysis of ATCC standard reference genomes (ASRGs) revealed significant issues with regard to NCBI’s RefSeq bacterial genome assemblies related to completeness, mutations, structure, strain metadata, and gaps in traceability to the original biological source materials. Nearly half of RefSeq assemblies lack details on sample source information, sequencing technology, or bioinformatics methods. Deep curation of these records is not within the scope of NCBI’s core mission in supporting open science, which aims to collect sequence records that are submitted by the public. Nonetheless, we propose that gaps in metadata accuracy and data provenance represent an “elephant in the room” for microbial genomics research. Effectively addressing these issues will require raising the level of accountability for data depositors and acknowledging the need for higher expectations of quality among the researchers whose research depends on accurate and attributable reference genome data.

IMPORTANCE The traceability of microbial genomics data to authenticated physical biological materials is not a requirement for depositing these data into public genome databases. This creates significant risks for the reliability and data provenance of these important genomics research resources, the impact of which is not well understood. We sought to investigate this by carrying out a comparative genomics study of 1,113 ATCC standard reference genomes (ASRGs) produced by ATCC from authenticated and traceable materials using the latest sequencing technologies. We found widespread discrepancies in genome assembly quality, genetic variability, and the quality and completeness of the associated metadata among hundreds of reference genomes for ATCC strains found in NCBI’s RefSeq database. We present a comparative analysis of de novo-assembled ASRGs, their respective metadata, and variant analysis using RefSeq genomes as a reference. Although assembly quality in RefSeq has generally improved over time, we found that significant quality issues remain, especially as related to genomic data and metadata provenance. Our work highlights the importance of data authentication and provenance for the microbial genomics community, and underscores the risks of ignoring this issue in the future.

Metabolic properties, gene functions, and biosafety analysis reveal the action of three rhizospheric plant growth-promoting bacteria of Jujuncao (Pennisetum giganteum)

This study aimed to identify the specific genes associated with plant growth promotion and cadmium tolerance in three bacteria strains associated with Pennisetum giganteum as well as to determine their biosafety levels in their potential use as biofertilizers for promoting plant growth and phytoremediation activities. The plant growth-promoting (PGP) abilities of Enterobacter cloacae strain RCB980 (A3), Klebsiella pneumonia strain kpa (A4), and Klebsiella sp. strain XT-2 (A7) were determined by a growth promotion trial and through testing for PGP traits such as 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase enzyme production, phosphorus solubilization, siderophore synthesis, and indole-3 acetic acid (IAA) production. The genes that potentially contribute to the beneficial activities of these three strains were identified through an analysis of their genomes. To establish the biosafety of the candidate PGPB, a pathological study was undertaken whereby 20 Kunming mice were injected intraperitoneally to study and analyze the effects of the strains on growth and lung paraffin sections of the mice. The strains had no obvious toxicity effect on the tested mice and were therefore not considered as highly virulent strains. These strains are thus considered non-toxic, safe, and highly recommended for use in environmental remediation strategies and agricultural production.

Comparative transcriptomic analysis of two Cucumis melo var. saccharinus germplasms differing in fruit physical and chemical characteristics

BACKGROUND

Hami melon (Cucumis melo var. saccharinus) is a popular fruit in China because of its excellent taste, which is largely determined by its physicochemical characteristics, including flesh texture, sugar content, aroma, and nutrient composition. However, the mechanisms by which these characteristics are regulated have not yet been determined. In this study, we monitored changes in the fruits of two germplasms that differed in physicochemical characteristics throughout the fruit development period.

RESULTS

Ripe fruit of the bred variety 'Guimi' had significantly higher soluble sugar contents than the fruit of the common variety 'Yaolong.' Additionally, differences in fruit shape and color between these two germplasms were observed during development. Comparative transcriptome analysis, conducted to identify regulators and pathways underlying the observed differences at corresponding stages of development, revealed a higher number of differentially expressed genes (DEGs) in Guimi than in Yaolong. Moreover, most DEGs detected during early fruit development in Guimi were associated with cell wall biogenesis. Temporal analysis of the identified DEGs revealed similar trends in the enrichment of downregulated genes in both germplasms, although there were differences in the enrichment trends of upregulated genes. Further analyses revealed trends in differential changes in multiple genes involved in cell wall biogenesis and sugar metabolism during fruit ripening.

CONCLUSIONS

We identified several genes associated with the ripening of Hami melons, which will provide novel insights into the molecular mechanisms underlying the development of fruit characteristics in these melons.

Bovine host genome acts on rumen microbiome function linked to methane emissions

Our study provides substantial evidence that the host genome affects the comprehensive function of the microbiome in the rumen of bovines. Of 1,107/225/1,141 rumen microbial genera/metagenome assembled uncultured genomes (RUGs)/genes identified from whole metagenomics sequencing, 194/14/337 had significant host genomic effects (heritabilities ranging from 0.13 to 0.61), revealing that substantial variation of the microbiome is under host genomic control. We found 29/22/115 microbial genera/RUGs/genes host-genomically correlated (|0.59| to |0.93|) with emissions of the potent greenhouse gas methane (CH4), highlighting the strength of a common host genomic control of specific microbial processes and CH4. Only one of these microbial genes was directly involved in methanogenesis (cofG), whereas others were involved in providing substrates for archaea (e.g. bcd and pccB), important microbial interspecies communication mechanisms (ABC.PE.P), host-microbiome interaction (TSTA3) and genetic information processes (RP-L35). In our population, selection based on abundances of the 30 most informative microbial genes provided a mitigation potential of 17% of mean CH4 emissions per generation, which is higher than for selection based on measured CH4 using respiration chambers (13%), indicating the high potential of microbiome-driven breeding to cumulatively reduce CH4 emissions and mitigate climate change.

A Novel and Ubiquitous Marine Methylophage Provides Insights into Viral-Host Coevolution and Possible Host-Range Expansion in Streamlined Marine Heterotrophic Bacteria

The methylotrophic OM43 clade are Gammaproteobacteria that comprise some of the smallest free-living cells known and have highly streamlined genomes. OM43 represents an important microbial link between marine primary production and remineralization of carbon back to the atmosphere. Bacteriophages shape microbial communities and are major drivers of mortality and global marine biogeochemistry. Recent cultivation efforts have brought the first viruses infecting members of the OM43 clade into culture. Here, we characterize a novel myophage infecting OM43 called Melnitz. Melnitz was isolated independently from water samples from a subtropical ocean gyre (Sargasso Sea) and temperate coastal (Western English Channel) systems. Metagenomic recruitment from global ocean viromes confirmed that Melnitz is globally ubiquitous, congruent with patterns of host abundance. Bacteria with streamlined genomes such as OM43 and the globally dominant SAR11 clade use riboswitches as an efficient method to regulate metabolism. Melnitz encodes a two-piece tmRNA (ssrA), controlled by a glutamine riboswitch, providing evidence that riboswitch use also occurs for regulation during phage infection of streamlined heterotrophs. Virally encoded tRNAs and ssrA found in Melnitz were phylogenetically more closely related to those found within the alphaproteobacterial SAR11 clade and their associated myophages than those within their gammaproteobacterial hosts. This suggests the possibility of an ancestral host transition event between SAR11 and OM43. Melnitz and a related myophage that infects SAR11 were unable to infect hosts of the SAR11 and OM43, respectively, suggesting host transition rather than a broadening of host range. IMPORTANCE Isolation and cultivation of viruses are the foundations on which the mechanistic understanding of virus-host interactions and parameterization of bioinformatic tools for viral ecology are based. This study isolated and characterized the first myophage known to infect the OM43 clade, expanding our knowledge of this understudied group of microbes. The nearly identical genomes of four strains of Melnitz isolated from different marine provinces and the global abundance estimations from metagenomic data suggest that this viral population is globally ubiquitous. Genome analysis revealed several unusual features in Melnitz and related genomes recovered from viromes, such as a curli operon and virally encoded tmRNA controlled by a glutamine riboswitch, neither of which are found in the host. Further phylogenetic analysis of shared genes indicates that this group of viruses infecting the gammaproteobacterial OM43 shares a recent common ancestor with viruses infecting the abundant alphaproteobacterial SAR11 clade. Host ranges are affected by compatible cell surface receptors, successful circumvention of superinfection exclusion systems, and the presence of required accessory proteins, which typically limits phages to singular narrow groups of closely related bacterial hosts. This study provides intriguing evidence that for streamlined heterotrophic bacteria, virus-host transitioning may not be necessarily restricted to phylogenetically related hosts but is a function of shared physical and biochemical properties of the cell.

Evaluation of Host Depletion and Extraction Methods for Shotgun Metagenomic Analysis of Bovine Vaginal Samples

The reproductive tract metagenome plays a significant role in the various reproductive system functions, including reproductive cycles, health, and fertility. One of the major challenges in bovine vaginal metagenome studies is host DNA contamination, which limits the sequencing capacity for metagenomic content and reduces the accuracy of untargeted shotgun metagenomic profiling. This is the first study comparing the effectiveness of different host depletion and DNA extraction methods for bovine vaginal metagenomic samples. The host depletion methods evaluated were slow centrifugation (Soft-spin), NEBNext Microbiome DNA Enrichment kit (NEBNext), and propidium monoazide (PMA) treatment, while the extraction methods were DNeasy Blood and Tissue extraction (DNeasy) and QIAamp DNA Microbiome extraction (QIAamp). Soft-spin and QIAamp were the most effective host depletion method and extraction methods, respectively, in reducing the number of cattle genomic content in bovine vaginal samples. The reduced host-to-microbe ratio in the extracted DNA increased the sequencing depth for microbial reads in untargeted shotgun sequencing. Bovine vaginal samples extracted with QIAamp presented taxonomical profiles which closely resembled the mock microbial composition, especially for the recovery of Gram-positive bacteria. Additionally, samples extracted with QIAamp presented extensive functional profiles with deep coverage. Overall, a combination of Soft-spin and QIAamp provided the most robust representation of the vaginal microbial community in cattle while minimizing host DNA contamination.

IMPORTANCE In addition to the host tissue collected during the sampling process, bovine vaginal samples are saturated with large amounts of extracellular DNA and secreted proteins that are essential for physiological purposes, including the reproductive cycle and immune defense. Due to the high host-to-microbe genome ratio, which hampers the sequencing efficacy for metagenome samples and the recovery of the actual metagenomic profiles, bovine vaginal samples cannot benefit from the full potential of shotgun sequencing. This is the first investigation on the most effective host depletion and extraction methods for bovine vaginal metagenomic samples. This study demonstrated an effective combination of host depletion and extraction methods, which harvested higher percentages of 16S rRNA genes and microbial reads, which subsequently led to a taxonomical profile that resembled the actual community and a functional profile with deeper coverage. A representative metagenomic profile is essential for investigating the role of the bovine vaginal metagenome for both reproductive function and susceptibility to infections.

MTD: a unique pipeline for host and meta-transcriptome joint and integrative analyses of RNA-seq data

Ribonucleic acid (RNA)-seq data contain not only host transcriptomes but also nonhost information that comprises transcripts from active microbiota in the host cells. Therefore, joint and integrative analyses of both host and meta-transcriptome can reveal gene expression of the microbial community in a given sample as well as the correlative and interactive dynamics of the host response to the microbiome. However, there are no convenient tools that can systemically analyze host-microbiota interactions through simultaneously quantifying the host and meta-transcriptome in the same sample at the tissue and the single-cell level. This poses a challenge for interested researchers with limited expertise in bioinformatics. Here, we developed a software pipeline that can comprehensively and synergistically analyze and correlate the host and meta-transcriptome in a single sample using bulk and single-cell RNA-seq data. This pipeline, named meta-transcriptome detector (MTD), can extensively identify and quantify microbiome, including viruses, bacteria, protozoa, fungi, plasmids and vectors, in the host cells and correlate the microbiome with the host transcriptome. MTD is easy to install and run, involving only a few lines of simple commands. It offers researchers with unique genomics insights into host responses to microorganisms.

Activity-based, genome-resolved metagenomics uncovers key populations and pathways involved in subsurface conversions of coal to methane

Microbial metabolisms and interactions that facilitate subsurface conversions of recalcitrant carbon to methane are poorly understood. We deployed an in situ enrichment device in a subsurface coal seam in the Powder River Basin (PRB), USA, and used BONCAT-FACS-Metagenomics to identify translationally active populations involved in methane generation from a variety of coal-derived aromatic hydrocarbons. From the active fraction, high-quality metagenome-assembled genomes (MAGs) were recovered for the acetoclastic methanogen, Methanothrix paradoxum, and a novel member of the Chlorobi with the potential to generate acetate via the Pta-Ack pathway. Members of the Bacteroides and Geobacter also encoded Pta-Ack and together, all four populations had the putative ability to degrade ethylbenzene, phenylphosphate, phenylethanol, toluene, xylene, and phenol. Metabolic reconstructions, gene analyses, and environmental parameters also indicated that redox fluctuations likely promote facultative energy metabolisms in the coal seam. The active "Chlorobi PRB" MAG encoded enzymes for fermentation, nitrate reduction, and multiple oxygenases with varying binding affinities for oxygen. "M. paradoxum PRB" encoded an extradiol dioxygenase for aerobic phenylacetate degradation, which was also present in previously published Methanothrix genomes. These observations outline underlying processes for bio-methane from subbituminous coal by translationally active populations and demonstrate activity-based metagenomics as a powerful strategy in next generation physiology to understand ecologically relevant microbial populations.

SufB intein splicing in Mycobacterium tuberculosis is influenced by two remote conserved N-extein histidines

Inteins are auto-processing domains that implement a multistep biochemical reaction termed protein splicing, marked by cleavage and formation of peptide bonds. They excise from a precursor protein, generating a functional protein via covalent bonding of flanking exteins. We report the kinetic study of splicing and cleavage reaction in [Fe–S] cluster assembly protein SufB from Mycobacterium tuberculosis (Mtu). Although it follows a canonical intein splicing pathway, distinct features are added by extein residues present in the active site. Sequence analysis identified two conserved histidines in the N-extein region; His-5 and His-38. Kinetic analyses of His-5Ala and His-38Ala SufB mutants exhibited significant reductions in splicing and cleavage rates relative to the SufB wildtype (WT) precursor protein. Structural analysis and molecular dynamics (MD) simulations suggested that Mtu SufB displays a unique mechanism where two remote histidines work concurrently to facilitate N-terminal cleavage reaction. His-38 is stabilized by the solvent-exposed His-5, and can impact N–S acyl shift by direct interaction with the catalytic Cys1. Development of inteins as biotechnological tools or as pathogen-specific novel antimicrobial targets requires a more complete understanding of such unexpected roles of conserved extein residues in protein splicing.

TreeTuner: A pipeline for minimizing redundancy and complexity in large phylogenetic datasets

Various bioinformatics protocols have been developed for trimming the number of operational taxonomic units (OTUs) in phylogenetic datasets, but they typically require significant manual intervention. Here we present TreeTuner, a semiautomated pipeline that allows both coarse and fine-scale tuning of large protein sequence phylogenetic datasets via the minimization of OTU redundancy. TreeTuner facilitates preliminary investigation of such datasets as well as more rigorous downstream analysis of specific subsets of OTUs. For complete details on the use and execution of this protocol, please refer to Maruyama et al. (2013) and Sibbald et al. (2019).

Comparative analysis of the Mercenaria mercenaria genome provides insights into the diversity of transposable elements and immune molecules in bivalve mollusks

BACKGROUND

The hard clam Mercenaria mercenaria is a major marine resource along the Atlantic coasts of North America and has been introduced to other continents for resource restoration or aquaculture activities. Significant mortality events have been reported in the species throughout its native range as a result of diseases (microbial infections, leukemia) and acute environmental stress. In this context, the characterization of the hard clam genome can provide highly needed resources to enable basic (e.g., oncogenesis and cancer transmission, adaptation biology) and applied (clam stock enhancement, genomic selection) sciences.

RESULTS

Using a combination of long and short-read sequencing technologies, a 1.86 Gb chromosome-level assembly of the clam genome was generated. The assembly was scaffolded into 19 chromosomes, with an N50 of 83 Mb. Genome annotation yielded 34,728 predicted protein-coding genes, markedly more than the few other members of the Venerida sequenced so far, with coding regions representing only 2% of the assembly. Indeed, more than half of the genome is composed of repeated elements, including transposable elements. Major chromosome rearrangements were detected between this assembly and another recent assembly derived from a genetically segregated clam stock. Comparative analysis of the clam genome allowed the identification of a marked diversification in immune-related proteins, particularly extensive tandem duplications and expansions in tumor necrosis factors (TNFs) and C1q domain-containing proteins, some of which were previously shown to play a role in clam interactions with infectious microbes. The study also generated a comparative repertoire highlighting the diversity and, in some instances, the specificity of LTR-retrotransposons elements, particularly Steamer elements in bivalves.

CONCLUSIONS

The diversity of immune molecules in M. mercenaria may allow this species to cope with varying and complex microbial and environmental landscapes. The repertoire of transposable elements identified in this study, particularly Steamer elements, should be a prime target for the investigation of cancer cell development and transmission among bivalve mollusks.

Allelically and Differentially Expressed Genes After Infection of Edwardsiella ictaluri in Channel Catfish as Determined by Bulk Segregant RNA-Seq

Identification of genetic markers associated with resistance against enteric septicemia of catfish (ESC) is of great interest for genetic enhancement programs of catfish. In the present study, bulk segregant RNA-Seq analysis was applied to determine differentially expressed genes and alleles after ESC infection. Here we report three genomic regions on LG1, LG12, and LG26, containing significant single-nucleotide polymorphisms (SNPs). These genomic regions aligned well with quantitative trait loci (QTL) previously identified. Within the QTL regions, eleven genes were found to be differentially regulated between phenotypic bulks. Importantly, the QTL on linkage group 1 (LG1) were found to be expressed in the liver, whereas the QTL on LG12 and LG26 were expressed in the intestine, suggesting multiple mechanisms of ESC resistance. It is apparent that apolipoproteins may be important for ESC resistance as the QTL on LG1 included the 14-kDa apolipoprotein genes that are both allelically expressed and differentially expressed between the resistant and susceptible bulks. Traf2 and NCK-interacting protein kinase (TNIK) were found in the QTL on LG12, and it was downregulated in resistant fish, suggesting the importance of NCK downregulation in ESC resistance, as previously reported. In addition, we observed divergent gene expression patterns between the liver and intestine after infection. Immune/inflammatory-related processes were overrepresented from liver DEGs, while those DEGs identified from intestine were enriched for proteolysis and wounding processes. Taken together, the BSR-Seq analysis presented here advanced the knowledge of ESC resistance, providing information of not only positions of QTL but also genes and their differential expression between resistant and susceptible fish, making it one step closer to the identification of the causal genes for ESC resistance.

Mutation-specific reporter for optimization and enrichment of prime editing

Prime editing is a versatile genome-editing technique that shows great promise for the generation and repair of patient mutations. However, some genomic sites are difficult to edit and optimal design of prime-editing tools remains elusive. Here we present a fluorescent prime editing and enrichment reporter (fluoPEER), which can be tailored to any genomic target site. This system rapidly and faithfully ranks the efficiency of prime edit guide RNAs (pegRNAs) combined with any prime editor variant. We apply fluoPEER to instruct correction of pathogenic variants in patient cells and find that plasmid editing enriches for genomic editing up to 3-fold compared to conventional enrichment strategies. DNA repair and cell cycle-related genes are enriched in the transcriptome of edited cells. Stalling cells in the G1/S boundary increases prime editing efficiency up to 30%. Together, our results show that fluoPEER can be employed for rapid and efficient correction of patient cells, selection of gene-edited cells, and elucidation of cellular mechanisms needed for successful prime editing.

Deciphering the link between Diabetes mellitus and SARS-CoV-2 infection through differential targeting of microRNAs in the human pancreas

PURPOSE

Coronavirus Disease 2019 (COVID-19) severity and Diabetes mellitus affect each other bidirectionally. However, the cause of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection on the incidence of diabetes is unclear. In the SARS-CoV-2-infected cells, host microRNAs (miRNAs) may target the native gene transcripts as well as the viral genomic and subgenomic RNAs. Here, we investigated the role of miRNAs in linking Diabetes to SARS-CoV-2 infection in the human pancreas.

METHODS

Differential gene expression and disease enrichment analyses were performed on an RNA-Seq dataset of human embryonic stem cell-derived (hESC) mock-infected and SARS-CoV-2-infected pancreatic organoids to obtain the dysregulated Diabetes-associated genes. The miRNA target prediction for the Diabetes-associated gene transcripts and the SARS-CoV-2 RNAs has been made to determine the common miRNAs targeting them. Minimum Free Energy (MFE) analysis was done to identify the miRNAs, preferably targeting SARS-CoV-2 RNAs over the Diabetes-associated gene transcripts.

RESULTS

The gene expression and disease enrichment analyses of the RNA-Seq data have revealed five biomarker genes, i.e., CP, SOCS3, AGT, PSMB8 and CFB that are associated with Diabetes and get significantly upregulated in the pancreas following SARS-CoV-2-infection. Four miRNAs, i.e., hsa-miR-298, hsa-miR-3925-5p, hsa-miR-4691-3p and hsa-miR-5196-5p, showed preferential targeting of the SARS-CoV-2 genome over the cell's Diabetes-associated messenger RNAs (mRNAs) in the human pancreas.

CONCLUSION

Our study proposes that the differential targeting of the Diabetes-associated host genes by the miRNAs may lead to diabetic complications or new-onset Diabetes that can worsen the condition of COVID-19 patients.

Perspectives on the landscape and flux theory for describing emergent behaviors of the biological systems

We give a review on the landscape theory of the equilibrium biological systems and landscape-flux theory of the nonequilibrium biological systems as the global driving force. The emergences of the behaviors, the associated thermodynamics in terms of the entropy and free energy and dynamics in terms of the rate and paths have been quantitatively demonstrated. The hierarchical organization structures have been discussed. The biological applications ranging from protein folding, biomolecular recognition, specificity, biomolecular evolution and design for equilibrium systems as well as cell cycle, differentiation and development, cancer, neural networks and brain function, and evolution for nonequilibrium systems, cross-scale studies of genome structural dynamics and experimental quantifications/verifications of the landscape and flux are illustrated. Together, this gives an overall global physical and quantitative picture in terms of the landscape and flux for the behaviors, dynamics and functions of biological systems.

NCMW: A Python Package to Analyze Metabolic Interactions in the Nasal Microbiome

The human upper respiratory tract is the reservoir of a diverse community of commensals and potential pathogens (pathobionts), including Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus, which occasionally turn into pathogens causing infectious diseases, while the contribution of many nasal microorganisms to human health remains undiscovered. To better understand the composition of the nasal microbiome community, we create a workflow of the community model, which mimics the human nasal environment. To address this challenge, constraint-based reconstruction of biochemically accurate genome-scale metabolic models (GEMs) networks of microorganisms is mandatory. Our workflow applies constraint-based modeling (CBM), simulates the metabolism between species in a given microbiome, and facilitates generating novel hypotheses on microbial interactions. Utilizing this workflow, we hope to gain a better understanding of interactions from the metabolic modeling perspective. This article presents nasal community modeling workflow (NCMW)—a python package based on GEMs of species as a starting point for understanding the composition of the nasal microbiome community. The package is constructed as a step-by-step mathematical framework for metabolic modeling and analysis of the nasal microbial community. Using constraint-based models reduces the need for culturing species in vitro, a process that is not convenient in the environment of human noses.

Availability: NCMW is freely available on the Python Package Index (PIP) via pip install NCMW. The source code, documentation, and usage examples (Jupyter Notebook and example files) are available at https://github.com/manuelgloeckler/ncmw.

Metagenomic Assessment of DNA Viral Diversity in Freshwater Sponges, Baikalospongia bacillifera

Sponges (type Porifera) are multicellular organisms that give shelter to a variety of microorganisms: fungi, algae, archaea, bacteria, and viruses. The studies concerning the composition of viral communities in sponges have appeared rather recently, and the diversity and role of viruses in sponge holobionts remain largely undisclosed. In this study, we assessed the diversity of DNA viruses in the associated community of the Baikal endemic sponge, Baikalospongia bacillifera, using a metagenomic approach, and compared the virome data from samples of sponges and Baikal water (control sample). Significant differences in terms of taxonomy, putative host range of identified scaffolds, and functional annotation of predicted viral proteins were revealed in viromes of sponge B. bacillifera and the Baikal water. This is the evidence in favor of specificity of viral communities in sponges. The diversity shift of viral communities in a diseased specimen, in comparison with a visually healthy sponge, probably reflects the changes in the composition of microbial communities in affected sponges. We identified many viral genes encoding the proteins with metabolic functions; therefore, viruses in Baikal sponges regulate the number and diversity of their associated community, and also take a part in the vital activity of the holobiont, and this is especially significant in the case of damage (or disease) of these organisms in unfavorable conditions. When comparing the Baikal viromes with similar datasets of marine sponge (Ianthella basta), in addition to significant differences in the taxonomic and functional composition of viral communities, we revealed common scaffolds/virotypes in the cross-assembly of reads, which may indicate the presence of some closely related sponge-specific viruses in marine and freshwater sponges.

Computational Design of a Multi-Epitope Vaccine Against Porphyromonas gingivalis

Porphyromonas gingivalis is a Gram-negative pathogenic bacterium associated with chronic periodontitis. The development of a chimeric peptide-based vaccine targeting this pathogen could be highly beneficial in preventing oral bone loss as well as other severe gum diseases. We applied a computational framework to design a multi-epitope-based vaccine candidate against P. gingivalis. The vaccine comprises epitopes from subunit proteins prioritized from the P. gingivalis reference strain (P. gingivalis ATCC 33277) using several reported vaccine properties. Protein-based subunit vaccines were prioritized through genomics techniques. Epitope prediction was performed using immunoinformatic servers and tools. Molecular modeling approaches were used to build a putative three-dimensional structure of the vaccine to understand its interactions with host immune cells through biophysical techniques such as molecular docking simulation studies and binding free energy methods. Genome subtraction identified 18 vaccine targets: six outer-membrane, nine cytoplasmic membrane-, one periplasmic, and two extracellular proteins. These proteins passed different vaccine checks required for the successful development of a vaccine candidate. The shortlisted proteins were subjected to immunoinformatic analysis to map B-cell derived T-cell epitopes, and antigenic, water-soluble, non-toxic, and good binders of DRB1*0101 were selected. The epitopes were then modeled into a multi-epitope peptide vaccine construct (linked epitopes plus adjuvant) to enhance immunogenicity and effectively engage both innate and adaptive immunity. Further, the molecular docking approach was used to determine the binding conformation of the vaccine to TLR2 innate immune receptor. Molecular dynamics simulations and binding free energy calculations of the vaccine–TLR2 complex were performed to highlight key intermolecular binding energies. Findings of this study will be useful for vaccine developers to design an effective vaccine for chronic periodontitis pathogens, specifically P. gingivalis.

Biodegradable and conventional microplastics exhibit distinct microbiome, functionality, and metabolome changes in soil

Environmental concerns with liberal petroleum-based plastic use have led to demand for sustainable biodegradable alternatives. However, the inadequate end-of-life treatment of plastics may emit microplastics, either conventional or biodegradable, to the terrestrial environment. It is essential to evaluate the possible effects of conventional and biodegradable microplastics on the composition and function of soil microbial communities. Therefore, we conducted a soil microcosm experiment with polyethylene (PE), polystyrene (PS), polylactide (PLA), or polybutylene succinate (PBS) microplastics. The soil microbiome and metabolome were evaluated via 16S rRNA gene sequencing, metagenomics, and untargeted metabolomics. We reported that the presence of conventional or biodegradable microplastics can significantly alter soil microbial community composition. Compared to the control soils, the microbiome in PBS and PLA amended soils exhibited higher potential for uptake of exogenous carbohydrates and amino acids, but a reduced capacity for related metabolic function, potentially due to catabolite repression. No differences in soil metabolome can be observed between conventional microplastic treatments and the control. The potential reason may be that the functional diversity was unaffected by PE and PS microplastics, while the biodegradable particles promoted the soil microbial multifunctionality. Our findings systematically shed light on the influence of conventional and biodegradable microplastics on soil microorganisms, facilitating microplastic regulation.

Comparison of Immune Checkpoint Molecules PD-1 and PD-L1 in Paired Primary and Recurrent Glioma: Increasing Trend When Recurrence

Purpose: This study aims to investigate PD-1/PD-L1 expression patterns in paired primary and recurrent gliomas. Methods: From January 2008 to December 2014, 42 patients who underwent surgical resections of primary and recurrent gliomas were retrospectively included. PD-1/PD-L1 protein expression in tumors was evaluated through immunohistochemistry. Results: In primary gliomas, PD-1 and PD-L1 expression was evident in 9 (22.0%) and 14 (33.3%) patients. In the paired recurrent glioma, PD-1 and PD-L1 expression was evident in 25 (61.0%) and 31 (74.0%) lesions. Both PD-1 and PD-L1 showed significantly enhanced expression after recurrence (p < 0.005; p < 0.005). For PD-L1 expression in recurrent gliomas, the adjuvant therapy group showed significantly increased expression compared to primary gliomas (p < 0.005). For PD-1- primary gliomas, if the matched recurrent gliomas showed PD-1+, the PFS became worse than the remaining recurrent gliomas PD-1- (12.7 vs. 25.9 months, p = 0.032). Interestingly, for PD-L1- primary gliomas, if the matched recurrent gliomas showed PD-L1+, the OS became better than the remaining recurrent gliomas PD-L1- (33.8 vs. 17.5 months, p < 0.001). Conclusions: In the study, we found the expression of PD-1/PD-L1 increased significantly in recurrent gliomas and the elevated level of PD-L1 was tightly associated with adjuvant treatment, suggesting the potential therapeutic and predictive value of PD-1 and PD-L1 in the treatment of recurrent gliomas.

Long-term spatiotemporal variation of antimicrobial resistance genes within the Serratia marcescens population and transmission of S. marcescens revealed by public whole-genome datasets

The development of antimicrobial resistance (AMR) is accelerated by the selective pressure exerted by the widespread use of antimicrobial drugs, posing an increasing danger to public health. However, long-term spatiotemporal variation in AMR genes in microorganisms, particularly in bacterial pathogens in response to antibiotic consumption, is not fully understood. Here, we used the NCBI RefSeq database to collect 478 whole-genome sequences for Serratia marcescens ranging from 1961 up to 2019, to document global long-term AMR trends in S. marcescens populations. In total, 100 AMR gene subtypes (16 AMR gene types) were detected in the genomes of S. marcescens populations. We identified 3 core resistance genes in S. marcescens genomes, and a high diversity of AMR genes was observed in S. marcescens genomes after corresponding antibiotics were discovered and introduced into clinical practice, suggesting the adaptation of S. marcescens populations to challenges with therapeutic antibiotics. Our findings indicate spatiotemporal variation of AMR genes in S. marcescens populations in relation to antibiotic consumption and suggest the potential transmission of S. marcescens isolates harboring AMR genes among countries and between the environment and the clinic, representing a public health threat that necessitates international solidarity to overcome.

In silico design of recombinant multi-epitope vaccine against influenza A virus

Background

Influenza A virus is one of the leading causes of annual mortality. The emerging of novel escape variants of the influenza A virus is still a considerable challenge in the annual process of vaccine production. The evolution of vaccines ranks among the most critical successes in medicine and has eradicated numerous infectious diseases. Recently, multi-epitope vaccines, which are based on the selection of epitopes, have been increasingly investigated.

Results

This study utilized an immunoinformatic approach to design a recombinant multi-epitope vaccine based on a highly conserved epitope of hemagglutinin, neuraminidase, and membrane matrix proteins with fewer changes or mutate over time. The potential B cells, cytotoxic T lymphocytes (CTL), and CD4 T cell epitopes were identified. The recombinant multi-epitope vaccine was designed using specific linkers and a proper adjuvant. Moreover, some bioinformatics online servers and datasets were used to evaluate the immunogenicity and chemical properties of selected epitopes. In addition, Universal Immune System Simulator (UISS) in silico trial computational framework was run after influenza exposure and recombinant multi-epitope vaccine administration, showing a good immune response in terms of immunoglobulins of class G (IgG), T Helper 1 cells (TH1), epithelial cells (EP) and interferon gamma (IFN-g) levels. Furthermore, after a reverse translation (i.e., convertion of amino acid sequence to nucleotide one) and codon optimization phase, the optimized sequence was placed between the two EcoRV/MscI restriction sites in the PET32a⁺ vector.

Conclusions

The proposed “Recombinant multi-epitope vaccine” was predicted with unique and acceptable immunological properties. This recombinant multi-epitope vaccine can be successfully expressed in the prokaryotic system and accepted for immunogenicity studies against the influenza virus at the in silico level. The multi-epitope vaccine was then tested with the Universal Immune System Simulator (UISS) in silico trial platform. It revealed slight immune protection against the influenza virus, shedding the light that a multistep bioinformatics approach including molecular and cellular level is mandatory to avoid inappropriate vaccine efficacy predictions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04581-6.

Comparative mutational analysis of SARS-CoV-2 isolates from Pakistan and structural-functional implications using computational modelling and simulation approaches

SARS-CoV-2, an RNA virus, has been prone to high mutations since its first emergence in Wuhan, China, and throughout its spread. Its genome has been sequenced continuously by many countries, including Pakistan, but the results vary. Understanding its genomic patterns and connecting them with phenotypic features will help in devising therapeutic strategies. Thus, in this study, we explored the mutation landscape of 250 Pakistani isolates of SARS-CoV-2 genomes to check the genome diversity and examine the impact of these mutations on protein stability and viral pathogenesis in comparison with a reference sequence (Wuhan NC 045512.2). Our results revealed that structural proteins mainly exhibit more mutations than others in the Pakistani isolates; in particular, the nucleocapsid protein is highly mutated. In comparison, the spike protein is the most mutated protein globally. Furthermore, nsp12 was found to be the most mutated NSP in the Pakistani isolates and worldwide. Regarding accessory proteins, ORF3A is the most mutated in the Pakistani isolates, whereas ORF8 is highly mutated in world isolates. These mutations decrease the structural stability of their proteins and alter different biological pathways. Molecular docking, the dissociation constant (KD), and MM/GBSA analysis showed that mutations in the S protein alter its binding with ACE2. The spike protein mutations D614G-S943T-V622F (-75.17 kcal/mol), D614G-Q677H (-75.78 kcal/mol), and N74K-D614G (-73.84 kcal/mol) exhibit stronger binding energy than the wild type (-66.34 kcal/mol), thus increasing infectivity. Furthermore, the simulation results strongly corroborated the predicted protein servers. Our analysis findings also showed that E, M, ORF6, ORF7A, ORF7B, and ORF10 are the most stable coding genes; they may be suitable targets for vaccine and drug development.

EST-SSR Marker Development and Full-Length Transcriptome Sequence Analysis of Tiger Lily (Lilium lancifolium Thunb)

The fast advancement and deployment of sequencing technologies after the Human Genome Project have greatly increased our knowledge of the eukaryotic genome sequences. However, due to technological concerns, high-quality genomic data has been confined to a few key organisms. Moreover, our understanding of which portions of genomes make up genes and which transcript isoforms synthesize these genes is scarce. Therefore, the current study has been designed to explore the reliability of the tiger lily (Lilium lancifolium Thunb) transcriptome. The PacBio-SMRT was used for attaining the complete transcriptomic profile. We obtained a total of 815,624 CCS (Circular Consensus Sequence) reads with an average length of 1295 bp. The tiger lily transcriptome has been sequenced for the first time using third-generation long-read technology. Furthermore, unigenes (38,707), lncRNAs (6852), and TF members (768) were determined based on the transcriptome data, followed by evaluating SSRs (3319). It has also been revealed that 105 out of 128 primer pairs effectively amplified PCR products. Around 15,608 transcripts were allocated to 25 distinct KOG Clusters, and 10,706 unigenes were grouped into 52 functional categories in the annotated transcripts. Until now, no tiger lily lncRNAs have been discovered. Results of this study may serve as an extensive set of reference transcripts and help us learn more about the transcriptomes of tiger lilies and pave the path for further research.

Genomic Insights Into Cadmium Resistance of a Newly Isolated, Plasmid-Free Cellulomonas sp. Strain Y8

Our current knowledge on bacterial cadmium (Cd) resistance is mainly based on the functional exploration of specific Cd-resistance genes. In this study, we carried out a genomic study on Cd resistance of a newly isolated Cellulomonas strain with a MIC of 5 mM Cd. Full genome of the strain, with a genome size of 4.47 M bp and GC-content of 75.35%, was obtained through high-quality sequencing. Genome-wide annotations identified 54 heavy metal-related genes. Four potential Cd-resistance genes, namely zntAY8, copAY8, HMTY8, and czcDY8, were subjected to functional exploration. Quantitative PCR determination of in vivo expression showed that zntAY8, copAY8, and HMTY8 were strongly Cd-inducible. Expression of the three inducible genes against time and Cd concentrations were further quantified. It is found that zntAY8 responded more strongly to higher Cd concentrations, while expression of copAY8 and HMTY8 increased over time at lower Cd concentrations. Heterologous expression of the four genes in Cd-sensitive Escherichia coli led to different impacts on hosts’ Cd sorption, with an 87% reduction by zntAY8 and a 3.7-fold increase by HMTY8. In conclusion, a Cd-resistant Cellulomonas sp. strain was isolated, whose genome harbors a diverse panel of metal-resistance genes. Cd resistance in the strain is not controlled by a dedicated gene alone, but by several gene systems collectively whose roles are probably time- and dose-dependent. The plasmid-free, high-GC strain Y8 may provide a platform for exploring heavy metal genomics of the Cellulomonas genus.

Designing a Recombinant Vaccine against Providencia rettgeri Using Immunoinformatics Approach

Antibiotic resistance (AR) is the resistance mechanism pattern in bacteria that evolves over some time, thus protecting the bacteria against antibiotics. AR is due to bacterial evolution to make itself fit to changing environmental conditions in a quest for survival of the fittest. AR has emerged due to the misuse and overuse of antimicrobial drugs, and few antibiotics are now left to deal with these superbug infections. To combat AR, vaccination is an effective method, used either therapeutically or prophylactically. In the current study, an in silico approach was applied for the design of multi-epitope-based vaccines against Providencia rettgeri, a major cause of traveler’s diarrhea. A total of six proteins: fimbrial protein, flagellar hook protein (FlgE), flagellar basal body L-ring protein (FlgH), flagellar hook-basal body complex protein (FliE), flagellar basal body P-ring formation protein (FlgA), and Gram-negative pili assembly chaperone domain proteins, were considered as vaccine targets and were utilized for B- and T-cell epitope prediction. The predicted epitopes were assessed for allergenicity, antigenicity, virulence, toxicity, and solubility. Moreover, filtered epitopes were utilized in multi-epitope vaccine construction. The predicted epitopes were joined with each other through specific GPGPG linkers and were joined with cholera toxin B subunit adjuvant via another EAAAK linker in order to enhance the efficacy of the designed vaccine. Docking studies of the designed vaccine construct were performed with MHC-I (PDB ID: 1I1Y), MHC-II (1KG0), and TLR-4 (4G8A). Findings of the docking study were validated through molecular dynamic simulations, which confirmed that the designed vaccine showed strong interactions with the immune receptors, and that the epitopes were exposed to the host immune system for proper recognition and processing. Additionally, binding free energies were estimated, which highlighted both electrostatic energy and van der Waals forces to make the complexes stable. Briefly, findings of the current study are promising and may help experimental vaccinologists to formulate a novel multi-epitope vaccine against P. rettgeri.

Improved 93-11 Genome and Time-Course Transcriptome Expand Resources for Rice Genomics

In 2002, the first crop genome was published using the rice cultivar 93-11, which is the progenitor of the first super-hybrid rice. The genome sequence has served as a reference genome for the indica cultivars, but the assembly has not been updated. In this study, we update the 93-11 genome assembly to a gap-less sequence using ultra-depth single molecule real-time (SMRT) reads, Hi-C sequencing, reference-guided, and gap-closing approach. The differences in the genome collinearity and gene content between the 93-11 and the Nipponbare reference genomes confirmed to map the indica cultivar sequencing data to the 93-11 genome, instead of the reference. Furthermore, time-course transcriptome data showed that the expression pattern was consistently correlated with the stages of seed development. Alternative splicing of starch synthesis-related genes and genomic variations of waxy make it a novel resource for targeted breeding. Collectively, the updated high quality 93-11 genome assembly can improve the understanding of the genome structures and functions of Oryza groups in molecular breeding programs.

Metagenomic Exploration of Koumiss from Kazakhstan

Here, we report a metagenomic analysis of koumiss from Kazakhstan. In this study, shotgun metagenomic sequencing of the RNA and DNA viral community was performed.

Integrated bioinformatics based subtractive genomics approach to decipher the therapeutic function of hypothetical proteins from Salmonella typhi XDR H-58 strain

Purpose

The efficacy of drugs against Salmonella infection have compromised due to emerging XDR H58 strain. There is a dire need to find novel antimicrobial drug targets as well as drug candidates to cure by the XDR strain of Salmonella. It is observed that the complete genome sequence of the XDR H58 strain contains a large number of hypothetical proteins with unknown cellular and biological functions. Hence, it is indispensable to annotate these proteins functionally as well as structurally to identify novel drug targets.

Methods

In the current study, a comparative genomics and proteomics based approach was applied to find the novel drug targets in XDR strain while comparing the MDR and NR strains of Salmonella typhi.

Results

The characterization of ~ 350 hypothetical proteins were performed through determination of their physio-chemical properties, sub-cellular localization, functional annotation, and structure-based studies. As a result, only five proteins were prioritized as essential, druggable, and virulent proteins. Moreover, only one protein i.e. WP_000916613.1 was functionally annotated with high confidence and subjected to further structure-based analysis.

Conclusion

The current study presents a hypothetical protein from the XDR S. typhi proteome as a potential pharmacological target against which novel therapeutic candidates may be predicted. The outcome of the current study may lead to formulate a general set of pipelines for better understanding of the role of hypothetical proteins in pathogenesis of not only Salmonella but also for other pathogens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10529-021-03219-6.

Actinoporin-like Proteins Are Widely Distributed in the Phylum Porifera

Actinoporins are proteinaceous toxins known for their ability to bind to and create pores in cellular membranes. This quality has generated interest in their potential use as new tools, such as therapeutic immunotoxins. Isolated historically from sea anemones, genes encoding for similar actinoporin-like proteins have since been found in a small number of other animal phyla. Sequencing and de novo assembly of Irish Haliclona transcriptomes indicated that sponges also possess similar genes. An exhaustive analysis of publicly available sequencing data from other sponges showed that this is a potentially widespread feature of the Porifera. While many sponge proteins possess a sequence similarity of 27.70–59.06% to actinoporins, they show consistency in predicted structure. One gene copy from H. indistincta has significant sequence similarity to sea anemone actinoporins and possesses conserved residues associated with the fundamental roles of sphingomyelin recognition, membrane attachment, oligomerization, and pore formation, indicating that it may be an actinoporin. Phylogenetic analyses indicate frequent gene duplication, no distinct clade for sponge-derived proteins, and a stronger signal towards actinoporins than similar proteins from other phyla. Overall, this study provides evidence that a diverse array of Porifera represents a novel source of actinoporin-like proteins which may have biotechnological and pharmaceutical applications.

Genomic studies controvert the existence of the CUX1 p75 isoform

CUX1, encoding a homeodomain-containing transcription factor, is recurrently deleted or mutated in multiple tumor types. In myeloid neoplasms, CUX1 deletion or mutation carries a poor prognosis. We have previously established that CUX1 functions as a tumor suppressor in hematopoietic cells across multiple organisms. Others, however, have described oncogenic functions of CUX1 in solid tumors, often attributed to truncated CUX1 isoforms, p75 and p110, generated by an alternative transcriptional start site or post-translational cleavage, respectively. Given the clinical relevance, it is imperative to clarify these discrepant activities. Herein, we sought to determine the CUX1 isoforms expressed in hematopoietic cells and find that they express the full-length p200 isoform. Through the course of this analysis, we found no evidence of the p75 alternative transcript in any cell type examined. Using an array of orthogonal approaches, including biochemistry, proteomics, CRISPR/Cas9 genomic editing, and analysis of functional genomics datasets across a spectrum of normal and malignant tissue types, we found no data to support the existence of the CUX1 p75 isoform as previously described. Based on these results, prior studies of p75 require reevaluation, including the interpretation of oncogenic roles attributed to CUX1.

Positive Selection and Horizontal Gene Transfer in the Genome of a Male-Killing Wolbachia

Wolbachia are a genus of widespread bacterial endosymbionts in which some strains can hijack or manipulate arthropod host reproduction. Male killing is one such manipulation in which these maternally transmitted bacteria benefit surviving daughters in part by removing competition with the sons for scarce resources. Despite previous findings of interesting genome features of microbial sex ratio distorters, the population genomics of male-killers remain largely uncharacterized. Here, we uncover several unique features of the genome and population genomics of four Arizonan populations of a male-killing Wolbachia strain, wInn, that infects mushroom-feeding Drosophila innubila. We first compared the wInn genome with other closely related Wolbachia genomes of Drosophila hosts in terms of genome content and confirm that the wInn genome is largely similar in overall gene content to the wMel strain infecting D. melanogaster. However, it also contains many unique genes and repetitive genetic elements that indicate lateral gene transfers between wInn and non-Drosophila eukaryotes. We also find that, in line with literature precedent, genes in the Wolbachia prophage and Octomom regions are under positive selection. Of all the genes under positive selection, many also show evidence of recent horizontal transfer among Wolbachia symbiont genomes. These dynamics of selection and horizontal gene transfer across the genomes of several Wolbachia strains and diverse host species may be important underlying factors in Wolbachia's success as a male-killer of divergent host species.

Bioinformatics and Computer Simulation approaches to the discovery and analysis of Bioactive Peptides

The traditional process of separating and purifying bioactive peptides is laborious and time-consuming. Using a traditional process to identify is difficult, and there is a lack of fast and accurate activity evaluation methods. How to extract bioactive peptides quickly and efficiently is still the focus of bioactive peptides research. In order to improve the present situation of the research, bioinformatics techniques and peptidome methods are widely used in this field. At the same time, bioactive peptides have their own specific pharmacokinetic characteristics, so computer simulation methods have incomparable advantages in studying the pharmacokinetics and pharmacokinetic-pharmacodynamic correlation models of bioactive peptides. The purpose of this review is to summarize the combined applications of bioinformatics and computer simulation methods in the study of bioactive peptides, with focuses on the role of bioinformatics in simulating the selection of enzymatic hydrolysis and precursor proteins, activity prediction, molecular docking, physicochemical properties, and molecular dynamics. Our review shows that new bioactive peptide molecular sequences with high activity can be obtained by computer-aided design. The significance of the pharmacokinetic-pharmacodynamic correlation model in the study of bioactive peptides is emphasized. Finally, some problems and future development potential of bioactive peptides binding new technologies are prospected.

Architectures and complex functions of tandem riboswitches

Riboswitch architectures that involve the binding of a single ligand to a single RNA aptamer domain result in ordinary dose-response curves that require approximately a 100-fold change in ligand concentration to cover nearly the full dynamic range for gene regulation. However, by using multiple riboswitches or aptamer domains in tandem, these ligand-sensing structures can produce additional, complex gene control outcomes. In the current study, we have computationally searched for tandem riboswitch architectures in bacteria to provide a more complete understanding of the diverse biological and biochemical functions of gene control elements that are made exclusively of RNA. Numerous different arrangements of tandem homologous riboswitch architectures are exploited by bacteria to create more 'digital' gene control devices, which operate over a narrower ligand concentration range. Also, two heterologous riboswitch aptamers are sometimes employed to create two-input Boolean logic gates with various types of genetic outputs. These findings illustrate the sophisticated genetic decisions that can be made by using molecular sensors and switches based only on RNA.

Computational identification of Plasmodium falciparum RNA pseudouridylate synthase as a viable drug target, its physicochemical properties, 3D structure prediction and prediction of potential inhibitors

The increased resistance to the currently effective antimalarial drugs against Plasmodium falciparum has necessitated the development of new drugs for malaria treatment. Many proteins have been predicted using various means as potential drug targets for the treatment of the P. falciparum malaria infection. Meanwhile, only a few studies went on to predict the 3-dimensional (3D) structure of potential target. Therefore, this study aimed to predict potential antimalarial drug targets against the deadliest malaria parasite P. falciparum as well as to determine the 3D structure and possible inhibitors of one of the targets. We employed machine learning approach to predict suitable drug targets in P. falciparum. Five of the predicted protein targets were considered as potential drug targets as they were non-homologous to their human counterparts. Out of these, we determined the physicochemical properties, predicted the 3D structure and carried out docking-based virtual screening of P. falciparum RNA pseudouridylate synthase, putative (PfRPuSP). The PfRPuSP was one of the potential five target proteins. Homology modelling and the ab initio methods were used to predict the 3D structure of PfRPuSP. Then, a compound library of 5621 molecules was constructed from PubChem and ChEMBL databases using 5-fluorouridine as the control inhibitor. Docking-based virtual screening was performed using Autodock 4.2 and Autodock Vina to select compounds with high binding affinity. A total of 11 compounds were selected based on their binding energies from 881 compounds which were manually examined after docking. Seven of the 11 compounds that exhibited remarkable interactions with the residues in the active sites of PfRPuSP were analysed. These compounds performed favourably when compared to the control inhibitor and predicted to bind better than 5-fluorouridine. These seven compounds are suggested as new potential lead structures for antimalarial treatment.

Technical note: overcoming host contamination in bovine vaginal metagenomic samples with nanopore adaptive sequencing

Animal metagenomic studies, in which host-associated microbiomes are profiled, are an increasingly important contribution to our understanding of the physiological functions, health and susceptibility to diseases of livestock. One of the major challenges in these studies is host DNA contamination, which limits the sequencing capacity for metagenomic content and reduces the accuracy of metagenomic profiling. This is the first study comparing the effectiveness of different sequencing methods for profiling bovine vaginal metagenomic samples. We compared the new method of Oxford Nanopore Technologies (ONT) adaptive sequencing, which can be used to target or eliminate defined genetic sequences, to standard ONT sequencing, Illumina 16S rDNA amplicon sequencing, and Illumina shotgun sequencing. The efficiency of each method in recovering the metagenomic data and recalling the metagenomic profiles was assessed. ONT adaptive sequencing yielded a higher amount of metagenomic data than the other methods per 1 Gb of sequence data. The increased sequencing efficiency of ONT adaptive sequencing consequently reduced the amount of raw data needed to provide sufficient coverage for the metagenomic samples with high host-to-microbe DNA ratio. Additionally, the long reads generated by ONT adaptive sequencing retained the continuity of read information, which benefited the in-depth annotations for both taxonomical and functional profiles of the metagenome. The different methods resulted in the identification of different taxa. Genera Clostridium, which was identified at low abundances and categorized under Order "Unclassified Clostridiales" when using the 16S rDNA amplicon sequencing method, was identified to be the dominant genera in the sample when sequenced with the three other methods. Additionally, higher numbers of annotated genes were identified with ONT adaptive sequencing, which also produced high coverage on most of the commonly annotated genes. This study illustrates the advantages of ONT adaptive sequencing in improving the amount of metagenomic data derived from microbiome samples with high host-to-microbe DNA ratio and the advantage of long reads in preserving intact information for accurate annotations.

TrpNet: Understanding Tryptophan Metabolism across Gut Microbiome

Crosstalk between the gut microbiome and the host plays an important role in animal development and health. Small compounds are key mediators in this host–gut microbiome dialogue. For instance, tryptophan metabolites, generated by biotransformation of tryptophan through complex host–microbiome co-metabolism can trigger immune, metabolic, and neuronal effects at local and distant sites. However, the origin of tryptophan metabolites and the underlying tryptophan metabolic pathway(s) are not well characterized in the current literature. A large number of the microbial contributors of tryptophan metabolism remain unknown, and there is a growing interest in predicting tryptophan metabolites for a given microbiome. Here, we introduce TrpNet, a comprehensive database and analytics platform dedicated to tryptophan metabolism within the context of host (human and mouse) and gut microbiome interactions. TrpNet contains data on tryptophan metabolism involving 130 reactions, 108 metabolites and 91 enzymes across 1246 human gut bacterial species and 88 mouse gut bacterial species. Users can browse, search, and highlight the tryptophan metabolic pathway, as well as predict tryptophan metabolites on the basis of a given taxonomy profile using a Bayesian logistic regression model. We validated our approach using two gut microbiome metabolomics studies and demonstrated that TrpNet was able to better predict alterations in in indole derivatives compared to other established methods.

Transcriptome of the Maize Leafhopper (Dalbulus maidis) and Its Transcriptional Response to Maize Rayado Fino Virus (MRFV), Which It Transmits in a Persistent, Propagative Manner

The corn leafhopper (Dalbulus maidis) is an important vector of maize rayado fino virus (MRFV), a positive-strand RNA (+ssRNA) marafivirus which it transmits in a persistent propagative manner. The interaction of D. maidis with MRFV, including infection of the insect and subsequent transmission to new plants, is not well understood at the molecular level. To examine the leafhopper-virus interaction, a D. maidis transcriptome was assembled and differences in transcript abundance between virus-exposed and naive D. maidis were examined at two time points (4 h and 7 days) post exposure to MRFV. The D. maidis transcriptome contained 56,116 transcripts generated from 1,727,369,026 100-nt paired-end reads from whole adult insects. The transcriptome of D. maidis shared highest identity and most orthologs with the leafhopper Graminella nigrifrons (65% of transcripts had matches with E values of <10^-5) versus planthoppers Sogatella furcifera (with 23% of transcript matches below the E value cutoff) and Peregrinus maidis (with 21% transcript matches below the E value cutoff), as expected based on taxonomy. D. maidis expressed genes in the Toll, Imd, and Jak/Stat insect immune signaling pathways, RNA interference (RNAi) pathway genes, prophenoloxidase-activating system pathways, and immune recognition protein-encoding genes such as peptidoglycan recognition proteins (PGRPs), antimicrobial peptides, and other effectors. Statistical analysis (performed by R package DESeq2) identified 72 transcripts at 4 h and 67 at 7 days that were significantly responsive to MRFV exposure. Genes expected to be favorable for virus propagation, such as protein synthesis-related genes and genes encoding superoxide dismutase, were significantly upregulated after MRFV exposure. IMPORTANCE The transcriptome of the corn leafhopper, D. maidis, revealed conserved biochemical pathways for immunity and discovered transcripts responsive to MRFV-infected plants at two time points, providing a basis for functional identification of genes that either limit or promote the virus-vector interaction. Compared to other hopper species and the propagative plant viruses they transmit, D. maidis shared 15 responsive transcripts with S. furcifera (to southern rice black-streaked dwarf virus [SRBSDV]), one with G. nigrifrons (to maize fine streak virus [MFSV]), and one with P. maidis (to maize mosaic virus [MMV]), but no virus-responsive transcripts identified were shared among all four hopper vector species.

Protocol for using NoBadWordsCombiner to merge and minimize "bad words" from BLAST hits against multiple eukaryotic gene annotation databases

Annotating protein-coding genes can be challenging, especially when searching for the best hits against multiple functional databases. This is partly because of "bad words" appearing as top hits, such as hypothetical or uncharacterized proteins. To help alleviate some of these issues, we designed a bioinformatics tool called NoBadWordsCombiner, which efficiently merges the hits from various databases, strengthening gene definitions by minimizing functional descriptions containing "bad words." Unlike other available tools, NoBadWordsCombiner is user friendly, but it does require users to have some general bioinformatics skills, including a basic understanding of the BLAST package and dash shell in Linux/Unix environments. For complete details on the use and execution of this protocol, please refer to Zhang et al. (2021a).

Transcriptome diversity and differential expression in supporting limb laminitis

Laminitis results in impaired tissue integrity and Inflammation of the epidermal and dermal lamellae connecting the hoof capsule to the underlying distal phalanx and causes loss-of-use, poor quality of life and euthanasia in horses. Historically, studies to better understand the etiology of laminitis by documenting changes in gene expression were hampered by the paucity of gene annotation specific to hoof tissues. Next-generation sequencing enables improvements to annotation by incorporating equine- and hoof-specific transcripts. Here we characterize the hoof lamellar tissue transcriptome of naturally occurring supporting limb laminitis (SLL) using archived lamellar tissue from Thoroughbred racehorses consisting of 13 SLL hospital cases and seven age-matched control horses. This was achieved using: 1) Applied transcriptome annotation by long-read sequencing to document transcript diversity and 2) short-read RNA sequencing to document changes in gene expression correlating to the developmental and acute stages of naturally occurring SLL. 1.99Gbp of long-read transcriptome sequencing deeply documented 5067 unique loci, while short read RNA-seq under very stringent quality filters described 66 differentially expressed loci. Functional analysis of these loci revealed alterations in cell replication and growth, stress response and leukocyte recruitment and activation pathways. Differential expression of the Ezrin and TIMP3 genes suggests they may have utility as biomarkers for laminitis disease, while NR1D1 and genes relevant to the inflammasome are promising targets for novel pharmacological treatments.

Plasma virome and the risk of blood-borne infection in persons with substance use disorder

There is an urgent need for innovative methods to reduce transmission of bloodborne pathogens like HIV and HCV among people who inject drugs (PWID). We investigate if PWID who acquire non-pathogenic bloodborne viruses like anelloviruses and pegiviruses might be at greater risk of acquiring a bloodborne pathogen. PWID who later acquire HCV accumulate more non-pathogenic viruses in plasma than matched controls who do not acquire HCV infection. Additionally, phylogenetic analysis of those non-pathogenic virus sequences reveals drug use networks. Here we find first in Baltimore and confirm in San Francisco that the accumulation of non-pathogenic viruses in PWID is a harbinger for subsequent acquisition of pathogenic viruses, knowledge that may guide the prioritization of the public health resources to combat HIV and HCV.

Spread of bloodborne infections, such as HCV and HIV, is a problem, particularly amongst people who inject drugs (PWID). Here, the authors describe and then confirm in observational PWID cohorts that those with more non-pathogenic viruses in plasma were more likely later to acquire HCV than PWID who had fewer of these non-pathogenic viruses.

High-Quality Genome-Scale Reconstruction of Corynebacterium glutamicum ATCC 13032

Corynebacterium glutamicum belongs to the microbes of enormous biotechnological relevance. In particular, its strain ATCC 13032 is a widely used producer of L-amino acids at an industrial scale. Its apparent robustness also turns it into a favorable platform host for a wide range of further compounds, mainly because of emerging bio-based economies. A deep understanding of the biochemical processes in C. glutamicum is essential for a sustainable enhancement of the microbe's productivity. Computational systems biology has the potential to provide a valuable basis for driving metabolic engineering and biotechnological advances, such as increased yields of healthy producer strains based on genome-scale metabolic models (GEMs). Advanced reconstruction pipelines are now available that facilitate the reconstruction of GEMs and support their manual curation. This article presents iCGB21FR, an updated and unified GEM of C. glutamicum ATCC 13032 with high quality regarding comprehensiveness and data standards, built with the latest modeling techniques and advanced reconstruction pipelines. It comprises 1042 metabolites, 1539 reactions, and 805 genes with detailed annotations and database cross-references. The model validation took place using different media and resulted in realistic growth rate predictions under aerobic and anaerobic conditions. The new GEM produces all canonical amino acids, and its phenotypic predictions are consistent with laboratory data. The in silico model proved fruitful in adding knowledge to the metabolism of C. glutamicum: iCGB21FR still produces L-glutamate with the knock-out of the enzyme pyruvate carboxylase, despite the common belief to be relevant for the amino acid's production. We conclude that integrating high standards into the reconstruction of GEMs facilitates replicating validated knowledge, closing knowledge gaps, and making it a useful basis for metabolic engineering. The model is freely available from BioModels Database under identifier MODEL2102050001.

PangenomeNet: a pan-genome-based network reveals functional modules on antimicrobial resistome for Escherichia coli strains

BACKGROUND

Discerning genes crucial to antimicrobial resistance (AMR) mechanisms is becoming more and more important to accurately and swiftly identify AMR pathogenic strains. Pangenome-wide association studies (e.g. Scoary) identified numerous putative AMR genes. However, only a tiny proportion of the putative resistance genes are annotated by AMR databases or Gene Ontology. In addition, many putative resistance genes are of unknown function (termed hypothetical proteins). An annotation tool is crucially needed in order to reveal the functional organization of the resistome and expand our knowledge of the AMR gene repertoire.

RESULTS

We developed an approach (PangenomeNet) for building co-functional networks from pan-genomes to infer functions for hypothetical genes. Using Escherichia coli as an example, we demonstrated that it is possible to build co-functional network from its pan-genome using co-inheritance, domain-sharing, and protein-protein-interaction information. The investigation of the network revealed that it fits the characteristics of biological networks and can be used for functional inferences. The subgraph consisting of putative meropenem resistance genes consists of clusters of stress response genes and resistance gene acquisition pathways. Resistome subgraphs also demonstrate drug-specific AMR genes such as beta-lactamase, as well as functional roles shared among multiple classes of drugs, mostly in the stress-related pathways.

CONCLUSIONS

By demonstrating the idea of pan-genome-based co-functional network on the E. coli species, we showed that the network can infer functional roles of the genes, including those without functional annotations, and provides holistic views on the putative antimicrobial resistomes. We hope that the pan-genome network idea can help formulate hypothesis for targeted experimental works.