Pairwise Identity Research Articles

Genomic analyses of a new baculovirus isolated from the wheat armyworm, Mythimna sequax (Franclemont) (Lepidoptera: Noctuidae)

We report the genomic analysis of a novel alphabaculovirus, Mythimna sequax nucleopolyhedrovirus isolate CNPSo-98 (MyseNPV-CNPSo-98), obtained from cadavers of the winter crop pest, Mythimna sequax Franclemont (Lepidoptera: Noctuidae). The insects were collected from rice fields in Southern Brazil in the 1980′s and belongs to the ‘EMBRAPA-Soja’ Virus Collection. High-throughput sequencing reads of DNA from MyseNPV occlusion bodies and assembly of the data yielded an AT-rich circular genome contig of 148,403 bp in length with 163 annotated opening reading frames (ORFs) and four homologous regions (hrs). Phylogenetic inference based on baculovirus core protein sequence alignments indicated that MyseNPV-CNPSo-98 is a member of Alphabaculovirus genus that clustered with other group II noctuid-infecting baculoviruses, including viruses isolated from Helicoverpa armigera and Mamestra spp. The genomes of the clade share strict collinearity and high pairwise nucleotide identity, with a common set of 149 genes, evolving under negative selection, except a bro gene. Branch lengths and Kimura-2-parameter pairwise nucleotide distances indicated that MyseNPV-CNPSo-98 represents a distinct lineage that may not be classified in any of the currently listed species in the genus.

Comparative Probiogenomics Analysis of Limosilactobacillus fermentum 3872.

Limosilactobacillus fermentum is an important member of the lactic acid bacteria group and holds immense potential for probiotic properties in human health and relevant industries. In this study, a comparative probiogenomic approach was applied to analyze the genome sequence of L. fermentum 3872, which was extracted from a commercially available yogurt sample, along with 20 different publicly available strains. Results indicate that the genome size of the characterized L. fermentum 3892 strain is 2,057,839bp, with a single- and circular-type chromosome possessing a G + C content of 51.69%. The genome of L. fermentum 3892 strain comprises a total of 2120 open reading frames (ORFs), two genes encoding rRNAs, and 53 genes encoding tRNAs. Upon comparative probiogenomic analysis, two plasmid sequences were detected among the study strains, including one for the L. fermentum 3872 genome, which was found between position 1,288,203 and 1,289,237 with an identity of 80.98. The whole-genome alignment revealed 2223 identical sites and a pairwise identity of 98.9%, indicating a significant difference of 1.1% among genome strains. Comparison of amino acid encoding genes among strains included in this study suggests that the strain 3872 exhibited the highest degree of amino acids present, including glutamine, glutamate, aspartate, asparagine, lysine, threonine, methionine, and cysteine. The comparative antibiotic resistome profiling revealed that strain 3872 exhibited a high resistant capacity only to ciprofloxacin antibiotics as compared to other strains. This study provides a genomic-based evaluation approach for comparative probiotic strain analysis in commercial foods and their significance to human health.

Characterization and evaluation of native Trichoderma harzianum P39 for biocontrol potentials against five seed-borne fungal pathogens of rice

Plant seeds can harbour pathogens that limits crop growth and productivity. This study isolated, characterised and evaluated native Trichoderma harzianum for antagonism against five (Alternaria alternata, Aspergillus oryzae, Bipolaris oryzae, Curvularia lunata and Fusarium verticillioides) fungal pathogens isolated from rice seeds. Evaluation was through simultaneous inoculation, a pathogen against the biocontrol agent, using the dual culture method in a PDA growth medium. Results confirmed the T. harzianum isolate had 98.27% pairwise identity with T. harzianum P39 (KX381171.1. accession number). The isolate showed increasing percentage inhibition, against all the pathogens, with increasing days after inoculation. The highest values ranged from 53.02%, A. oryzae to 70.06%, F. verticillioides (the least and most susceptible respectively). The overall inhibition percentages of A. alterata and B. oryzae (12th day after inoculation) were not significantly different from that of F. verticillioides. Trichoderma harzianum P39 can be formulated as biological seed dressing agent.

First Report of Globisporangium (Pythium) mastophorum causing Damping-off / Root Rot on Parsley in Slovenia.

Pythium-like species cause damping-off symptoms of various hosts, including umbelliferous crops. In April 2023, parsley plantlets (Petroselinum crispum), showing stunted growth, yellowing, decayed roots and damping-off, were obtained from a nursery in central Slovenia, where parsley was grown in polystyrene trays in a greenhouse. Nearly 30% of plants were symptomatic. Sampled roots of ten plants contained ornamented oogonia (avg. 33.3 ± 1.4 µm in diam) with conical projections (5.2 ± 0.5 µm long) (Figure S1 A, B) in microscopically analyzed squash mounts. The pathogen was isolated from root pieces treated for surface disinfection with 0.5% sodium hypochlorite for 30 s, and washed with sterile water. Four 1-2 mm root pieces were taken from each of 10 plants, plated on the selective medium P5ARP, and incubated at 21 °C. Mycelia emerging from root pieces were transferred to carrot piece agar (CPA). Twenty-two equally looking oomycetous colonies were obtained; all sampled plants were infested. Oogonia formed by all colonies were similar to those observed on decayed roots and suggested that Globisporangium (Pythium) mastophorum is the causal disease agent. Analyses of partial β-tubulin (Kroon et al. 2004) and mitochondrial cytochrome c oxidase I (COI) gene sequences (Robideau et al. 2011) confirmed the identification. Obtained COI (Genbank accession number OR725417) sequence was 100% identical to that from G. mastophorum strain CBS 375.72 (EU350523), whereas the β-tubulin sequence (OR725416) corresponded to 99.6 % pairwise identity (KJ595502). Further, pathogenicity of an obtained isolate was tested on 4 wk-old curly leaf (cv. Petra F1) parsley. Half of a 7 d-old CPA culture, consisting of mycelium and oogonia, was finely cut and mixed with ca 50 ml of nonsterile commercial substrate (Potgrond H, AGRO-FertiCrop) in each of six 400 ml pots. Pots were filled with ca 300 ml additional substrate, into which 5 parsley seedlings were planted. Control plants were treated equally but with sterile CPA. Plantlets were watered with sterile tap water and held at ambient light conditions and temperature (night 18 °C - day 23 °C). After 14 d, inoculated plants started wilting and yellowing and showed stunted growth. After 21 d, roots were severely decayed and the seedlings damped-off (Figure S1 C). Four pieces each from 10 decayed roots were plated. Thirty-one pieces revealed pythium-like colonies. Obtained isolates were morphologically identical to the strain used for inoculation and identified as G. mastophorum. Control plants developed no foliar or root symptoms and no pythium-like species was obtained. Agricultural advisors observed occurrence of parsley damping-off also in other nurseries in Slovenia what may lead to spreading the pathogen to parsley in production fields and private gardens. The case emphasizes the need for implementing phytosanitary measures in order to eliminate primary inoculum. Reports from field-infected plants showed that G. mastophorum is a pathogen of parsley in Australia (Petkowski et al. 2013) and the USA (Tsuchida et al. 2018), and celery in the Czech Republic (Šafránková and Holková 2017). Others isolated G. mastophorum from parsley in The Netherlands (online database of the Westerdijk Fungal Biodiversity Institute, strain CBS 243.86). However, the here described case is, to the best of our knowledge, one of the rare documentations of damping-off due to G. mastophorum in Europe (Šafránková and Holková 2017) and the first in Slovenia. Funding: The work was funded by the Ministry of Agriculture, Forestry and Food of Slovenia, and Slovenian Research and Innovation Agency (ARIS Programs P4-0431 and P4-0072).

Investigation of canine parvovirus occurrence in cats with clinical signs of feline panleukopenia in Slovakia - pilot study.

Feline panleukopenia is a contagious viral disease caused by the feline panleukopenia virus (FPV). A closely related pathogen is canine parvovirus (CPV), and amino acid substitutions in this virus allow it to acquire a feline host range. In feline hosts, the disease induced by CPV manifests with similar symptoms to those caused by FPV or milder ones, leading to its underdiagnosis. The aim of this study was to determine the presence of CPV type 2 (CPV-2) in cats with clinical symptoms of panleukopenia and to assess the use of commercial CPV antigen tests for the clinical diagnosis of FPV. Samples from 59 cats from central Slovakia were included in the study. Rectal swabs were collected and clinically tested for parvovirus infection using a commercial antigen test. Antigen-positive samples were confirmed by PCR targeting the viral VP2 gene. The sequences of the PCR products were established with the Sanger method. Of 59 samples, 23 were revealed to be positive for parvovirus infection by both antigen and PCR test (38.9%). Analysis with the National Center for Biotechnology Information BLASTn application showed 99.78-100% pairwise identity with FPV. The mortality rate of parvovirus-infected cats included in this study was 8.69% (2/23). Although feline disease with CPV-2 was not confirmed, the CPV antigen test was able to detect FPV infection.

Refining the taxonomy of the order Hyphomicrobiales (Rhizobiales) based on whole genome comparisons of over 130 type strains.

The alphaproteobacterial order Hyphomicrobiales consists of 38 families comprising at least 152 validly published genera as of January 2024. The order Hyphomicrobiales was first described in 1957 and underwent important revisions in 2020. However, we show that several inconsistencies in the taxonomy of this order remain and we argue that there is a need for a consistent framework for defining families within the order. We propose a common genome-based framework for defining families within the order Hyphomicrobiales, suggesting that families represent monophyletic groups in core-genome phylogenies that share pairwise average amino acid identity values above ~75 % when calculated from a core set of 59 proteins. Applying this framework, we propose the formation of four new families and to reassign the genera Salaquimonas, Rhodoblastus, and Rhodoligotrophos into Salaquimonadaceae fam. nov., Rhodoblastaceae fam. nov., and Rhodoligotrophaceae fam. nov., respectively, and the genera Albibacter, Chenggangzhangella, Hansschlegelia, and Methylopila into Methylopilaceae fam. nov. We further propose to unify the families Bartonellaceae, Brucellaceae, Phyllobacteriaceae, and Notoacmeibacteraceae as Bartonellaceae; the families Segnochrobactraceae and Pseudoxanthobacteraceae as Segnochrobactraceae; the families Lichenihabitantaceae and Lichenibacteriaceae as Lichenihabitantaceae; and the families Breoghaniaceae and Stappiaceae as Stappiaceae. Lastly, we propose to reassign several genera to existing families. Specifically, we propose to reassign the genus Pseudohoeflea to the family Rhizobiaceae; the genera Oricola, Roseitalea, and Oceaniradius to the family Ahrensiaceae; the genus Limoniibacter to the emended family Bartonellaceae; the genus Faunimonas to the family Afifellaceae; and the genus Pseudochelatococcus to the family Chelatococcaceae. Our data also support the recent proposal to reassign the genus Prosthecomicrobium to the family Kaistiaceae.

Graphical models for identifying pore-forming proteins.

Pore-forming toxins (PFTs) are proteins that form lesions in biological membranes. Better understanding of the structure and function of these proteins will be beneficial in a number of biotechnological applications, including the development of new pest control methods in agriculture. When searching for new pore formers, existing sequence homology-based methods fail to discover truly novel proteins with low sequence identity to known proteins. Search methodologies based on protein structures would help us move beyond this limitation. As the number of known structures for PFTs is very limited, it's quite challenging to identify new proteins having similar structures using computational approaches like deep learning. In this article, we therefore propose a sample-efficient graphical model, where a protein structure graph is first constructed according to consensus secondary structures. A semi-Markov conditional random fields model is then developed to perform protein sequence segmentation. We demonstrate that our method is able to distinguish structurally similar proteins even in the absence of sequence similarity (pairwise sequence identity < 0.4)-a feat not achievable by traditional approaches like HMMs. To extract proteins of interest from a genome-wide protein database for further study, we also develop an efficient framework for UniRef50 with 43 million proteins.

Two Novel Geminiviruses Identified in Bees (Apis mellifera and Nomia sp.).

Members of the Geminviridae family are circular single-stranded DNA plant-infecting viruses, some of which impact global food production. Geminiviruses are vectored by sap-feeding insects such as leafhoppers, treehoppers, aphids, and whiteflies. Additionally, geminivirus sequences have also been identified in other insects such as dragonflies, mosquitoes, and stingless bees. As part of a viral metagenomics study on honeybees and solitary bees (Nomia sp.), two geminivirus genomes were identified. These represent a novel citlodavirus (from honeybees collected from Westmoreland, Jamaica) and a mastrevirus-like genome (from a solitary bee collected from Tempe, Arizona, USA). The novel honeybee-derived citlodavirus genome shares ~61 to 69% genome-wide nucleotide pairwise identity with other citlodavirus genome sequences and is most closely related to the passion fruit chlorotic mottle virus identified in Brazil. Whereas the novel solitary bee-derived mastrevirus-like genome shares ~55 to 61% genome-wide nucleotide identity with other mastreviruses and is most closely related to tobacco yellow dwarf virus identified in Australia, based on pairwise identity scores of the full genome, replication-associated protein, and capsid protein sequences. Previously, two geminiviruses in the Begomovirus genus were identified in samples of stingless bee (Trigona spp.) samples. Here, we identify viruses that represent two new species of geminiviruses from a honeybee and a solitary bee, which continues to demonstrate that plant pollinators can be utilized for the identification of plant-infecting DNA viruses in ecosystems.

Increased begomovirus disease incidence and severity in cucurbits associated with the emergence of CuLCrV in mixed infection with SLCuV in Baja California Sur, Mexico

Begomoviral diseases in cucurbits have been observed in Baja California Sur (BCS), Mexico recurrently since the 2017 detection of the Squash leaf curl virus (SLCuV) in squash. Two years later, samples of symptomatic plants were collected in three arid agricultural regions, where the most frequently observed symptoms were chlorosis, reduced leaf size, stunting and severe leaf deformation, observed mainly on squash and cantaloupe. The mean incidence of begomovirus-like symptoms differed among cucurbits, with 20% in cucumber, 28% in cantaloupe, 30% in watermelon and 50% in squash. Samples were tested by polymerase chain reaction for begomovirus infection with degenerate primers, and later the virus identities were confirmed by specific primer pairs. All symptomatic cucurbit samples tested positive for SLCuV, and in a second analysis of these previously tested samples, squash, and cantaloupe samples tested positive for Cucurbit leaf crumple virus (CuLCrV). Thus, these samples showed a mixed CuLCrV/SLCuV infection. Pairwise identity analysis of the DNA-A component of the viruses indicated the presence of CuLCrV at 99%, and SLCuV at 99.1%. Recombination analyses between these viruses were negative, indicating that they belong to well-defined phylogenetic groups. Additionally, the 5´-TGGTGTCC-3´ iteron was consistently observed in all SLCuV and CuLCrV variants, including in other close species of the SLCuV clade. However, an additional iteron was observed in CuLCrV-BCS that is not in the Arizona and California variants, indicating that more studies are needed to elucidate the role of the additional iteron and the importance of CuLCrV/SLCuVSLCV mixed infection in emerging viruses in Mexico and other parts of the world.

First Detection of Atractylodes Mild Mottle Virus in Atractylodes lancea (Thunb.) DC. in Hubei Province of China.

The cultivated aromatic medicinal herb Atractylodes lancea (Thunb.) DC. is widely used in the pharmaceuticals, nutraceuticals, and cosmetics industries (Na-Bangchang et al. 2014; Zhan et al. 2023). Huanggang in Hubei Province is a major production area for A. lancea (Huang et al. 2022; Wang et al. 2023). In April 2023, more than two-thirds of the surveyed plant leaves in this region exhibited virus-like symptoms, such as curling and mosaic patterns. To identify the underlying cause, 80 symptomatic plant leaf samples were collected from four fields (20 leaves per field) in this region and pooled for virome analysis. Total RNA, including ribosomal RNA, was extracted from the pooled samples using the Plant RNA Extraction Mini Kit (Onrew Biotech, Guangdong, China), for sequencing library construction. The Illumina NovaSeq 6000 platform was used to sequence the library and generate 150 bp paired-end reads. After processing the raw data with Trimmomatic software, a total of 44,354,650 high-quality clean reads were obtained. The clean reads were aligned against ribosomal RNA using BWA software (v0.7.17) to avoid interference and eliminate corresponding sequences. After removing potential contamination, contig assembly of the clean reads was performed using Megahit software (v1.2.9). The resulting contigs were compared with the virus NT database using the BLASTn program. Sequence pairwise comparison revealed 8 contigs (574 nt to 2243 nt) with identities ranging from 81.88% to 90.77% with Atractylodes mild mottle virus (AMMV, NC_027924.1, Lim et al., 2015). Additionally, contigs mapped to Carlavirus, Pelarspovirus, and other plant viruses in our virome dataset had low coverage and pairwise identity (less than 70%), which need to be further investigated. The presence of AMMV was confirmed by aligning the clean reads to the reference sequence (NC_027924.1) using BWA and SAMtools software, resulting in a consensus sequence (8024 nt) with gaps. DNA extraction from the pooled samples was performed using the Rapid Universal Genomic DNA Extraction Kit (Simgen, Zhejiang, China). Two pairs of specific primers, 3399F (5'-AAAGAAGAACCTCCTGATACGG-3')/5924R (5'-TGAACCTGATTCTCTTGGC-3') and 1830F (5'- CTCAGGAAATCCCAATGC -3')/3640R(5'-TTTCCCAATGTTCTTCGGG-3'), were designed to amplify the complete gene sequences of polymerase and coat protein (CP), based on the consensus sequence. The PCR products with the lengths of 2521 bp and 1814 bp were cloned into the pMD18-T vector (Takara Biotech, Dalian, China) for sequencing. The BLASTn analysis showed that the polymerase and CP gene sequences shared an identity of 94.51% (1929/2041 nt) and 88.41% (1419/1605 nt) with the AMMV isolate (NC_027924.1), respectively. The sequences have been deposited in GenBank under the accession numbers OR544810 and OR544811. We collected leaves from 32 A. lancea plants (16 symptomatic and 16 asymptomatic) in the fields. RT-PCR was conducted using CPF (5'-CTGCGAATATGAAAGTGC-3') and CPR (5'-GGTGAGCTTGTCTGTTAGG-3') primers, which were designed targeting a 527bp fragment of the CP gene (OR544811). Amplicons of the expected size (527bp) were detected in 24 plants (11 symptomatic and 13 asymptomatic), three of which were sequenced by Sanger sequencing, showing a 100% match to OR544811. These findings indicate that AMMV is prevalent in the major production area of A. lancea. Further research is needed to better characterize the potential risks of AMMV to A. lancea cultivation in China as well as other countries.

A review on recent taxonomic updates of gut bacteria associated with social bees, with a curated genomic reference database.

Honeybees and bumblebees play a crucial role as essential pollinators. The special gut microbiome of social bees is a key factor in determining the overall fitness and health of the host. Although bees harbor relatively simple microbial communities at the genus level, recent studies have unveiled significant genetic divergence and variations in gene content within each bacterial genus. However, a comprehensive and refined genomics-based taxonomic database specific to social bee gut microbiomes remains lacking. Here, we first provided an overview of the current knowledge on the distribution and function of social bee gut bacteria, as well as the factors that influence the gut population dynamics. We then consolidated all available genomes of the gut bacteria of social bees and refined the species-level taxonomy, by constructing a maximum-likelihood core genome phylogeny and calculating genome-wide pairwise average nucleotide identity. On the basis of the refined species taxonomy, we constructed a curated genomic reference database, named the bee gut microbe genome sequence database (BGM-GDb). To evaluate the species-profiling performance of the curated BGM-GDb, we retrieved a series of bee gut metagenomic data and inferred the species-level composition using metagenomic intra-species diversity analysis system (MIDAS), and then compared the results with those obtained from a prebuilt MIDAS database. We found that compared with the default database, the BGM-GDb excelled in aligned read counts and bacterial richness. Overall, this high-resolution and precise genomic reference database will facilitate research in understanding the gut community structure of social bees.

Evaluating the mitochondrial genomic diversity, global distribution and niche overlap of two invasive Phthorimaea species

This study sought to evaluate the genetic diversity of two invasive Phthorimaea species (Phthorimaea operculella Zeller and Phthorimaea absoluta Meyrick), and identify potential niche overlap of both species. The complete mitogenomes of P. operculella and P. absoluta were sequenced and compared. Furthermore, the diversity within the family Gelechiidae was assessed. Subsequently, two species distribution models (MaxEnt and BIOCLIM) were used to identify niche overlaps of both species globally. The complete mitogenomes of both species were similar in size and structure, with a pairwise identity of 92.3%. The models showed a niche overlap of both species and revealed areas of marginal to high suitability for both pests in countries where they have not been reported. Therefore, these results present a compelling case for a deeper genetic and ecological investigation of the Gelechiidae family for taxonomic harmonization, an early warning for surveillance, stricter phytosanitary considerations and preventive management against the spread of the pests.

Rathayibacter tanaceti sp. nov., a Novel Actinobacterium from Tanacetum vulgare Infested by Foliar Nematode Aphelenchoides sp.

Two novel yellow-pigmented, rod-shaped and non-motile coryneform actinobacteria, strains VKM Ac-2596T and VKM Ac-2761, were isolated from a plant Tanacetum vulgare (Asteraceae) infested by foliar nematode Aphelenchoides sp. The strains exhibited the highest 16S rRNA gene sequence similarities to Rathayibacter agropyri CA4T (99.71%), Rathayibacter rathayi DSM 7485T (99.65%) and Rathayibacter iranicus VKM Ac-1602T (99.65%). The pairwise average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between VKM Ac-2596T and VKM Ac-2671 towards the type strains of Rathayibacter species did not exceed 85.24% and 29.40%, respectively, that are well below the thresholds for species delineation. The target strains had key chemotaxonomic properties typical of the genus Rathayibacter, namely, the DAB-based peptidoglycan, rhamnose and mannose as the predominant sugars and a rhamnomannan in the cell, the major menaquinone MK-10 and fatty acids of iso-anteiso type, with a large proportion of anteiso-15:0. The strains showed clear differences from the recognized Rathayibacter species in several phenotypic characteristics, including the difference in the composition of cell wall glycopolymers. Based on the results obtained in this study and the data published previously, we provide a description of a new species, Rathayibacter tanaceti sp. nov., with DL-642T (= VKM Ac-2596T = LMG 33114T) as the type strain.

Metagenomic Detection and Genetic Characterization of Human Sapoviruses among Children with Acute Flaccid Paralysis in Nigeria.

Using a metagenomic sequencing approach on stool samples from children with Acute Flaccid Paralysis (AFP), we describe the genetic diversity of Sapoviruses (SaVs) in children in Nigeria. We identified six complete genome sequences and two partial genome sequences. Several SaV genogroups and genotypes were detected, including GII (GII.4 and GII.8), GIV (GIV.1), and GI (GI.2 and GI.7). To our knowledge, this is the first description of SaV infections and complete genomes from Nigeria. Pairwise identity and phylogenetic analysis showed that the Nigerian SaVs were related to previously documented gastroenteritis outbreaks with associated strains from China and Japan. Minor variations in the functional motifs of the nonstructural proteins NS3 and NS5 were seen in the Nigerian strains. To adequately understand the effect of such amino acid changes, a better understanding of the biological function of these proteins is vital. The identification of distinct SaVs reinforces the need for robust surveillance in acute gastroenteritis (AGE) and non-AGE cohorts to better understand SaVs genotype diversity, evolution, and its role in disease burden in Nigeria. Future studies in different populations are, therefore, recommended.

Molecular characterization and pathogenicity of a novel monopartite geminivirus infecting tobacco in China

The occurrence of geminiviruses causes significant economic losses in many economically important crops. In this study, a novel geminivirus isolated from tobacco in Sichuan province of China, named tomato leaf curl Chuxiong virus (TLCCxV), was characterized by small RNA-based deep sequencing. The full-length of TLCCxV genome was determined to be 2744 nucleotides (nt) encoding six open reading frames. Phylogenetic and genome-wide pairwise identity analysis revealed that TLCCxV shared less than 91% identities with reported geminiviruses. A TLCCxV infectious clone was constructed and successfully infected Nicotiana benthamiana, N. tabacum, N. glutinosa, Solanum lycopersicum and Petunia hybrida plants. Furthermore, expression of the V2, C1 and C4 proteins through a potato virus X vector caused severe chlorosis or necrosis symptom in N. benthamiana. Taken together, we identified a new geminivirus in tobacco plants, and found that V2, C1 and C4 contribute to symptom development.

The chloroplast and mitochondrial genomes of two Gomphonema parvulum (Bacillariophyta) environmental isolates from South Carolina (United States) and Virginia (United States).

Gomphonema parvulum is a cosmopolitan freshwater diatom that is used as an indicator in water quality biomonitoring. In this study, we report the culturing of two geographically separated isolates from southeastern North America, their morphology, and the sequencing and assembly of their mitochondrial and chloroplast genomes. Morphologically, both strains fit G. parvulum sensu lato, but the frustules from a protected habitat in South Carolina were smaller than those cited in the historic data of this species from the same location as well as a second culture from Virginia. Phylogenetic analyses using the rbcL gene placed both within a clade with G. parvulum. Genetic markers, including full chloroplast and mitochondrial genomes and the nuclear small subunit rRNA gene region were assembled from each isolate. The organellar genomes of the two strains varied slightly in size due to small differences in intergenic regions with chloroplast genomes of 121,035 bp and 121,482 bp and mitochondrial genomes of 34,639 bp and 34,654 bp. The intraspecific pairwise identities of the chloroplast and mitochondrial genomes of these two isolates were 97.9% and 95.4%, respectively. Multigene phylogenetic analysis demonstrated a close relationship between G. parvulum, Gomphoneis minuta, and Didymosphenia geminata.

Protein embedding based alignment

PurposeDespite the many progresses with alignment algorithms, aligning divergent protein sequences with less than 20–35% pairwise identity (so called "twilight zone") remains a difficult problem. Many alignment algorithms have been using substitution matrices since their creation in the 1970’s to generate alignments, however, these matrices do not work well to score alignments within the twilight zone. We developed Protein Embedding based Alignments, or PEbA, to better align sequences with low pairwise identity. Similar to the traditional Smith-Waterman algorithm, PEbA uses a dynamic programming algorithm but the matching score of amino acids is based on the similarity of their embeddings from a protein language model.MethodsWe tested PEbA on over twelve thousand benchmark pairwise alignments from BAliBASE, each one extracted from one of their multiple sequence alignments. Five different BAliBASE references were used, each with different sequence identities, motifs, and lengths, allowing PEbA to showcase how well it aligns under different circumstances.ResultsPEbA greatly outperformed BLOSUM substitution matrix-based pairwise alignments, achieving different levels of improvements of the alignment quality for pairs of sequences with different levels of similarity (over four times as well for pairs of sequences with <10% identity). We also compared PEbA with embeddings generated by different protein language models (ProtT5 and ESM-2) and found that ProtT5-XL-U50 produced the most useful embeddings for aligning protein sequences. PEbA also outperformed DEDAL and vcMSA, two recently developed protein language model embedding-based alignment methods.ConclusionOur results suggested that general purpose protein language models provide useful contextual information for generating more accurate protein alignments than typically used methods.

Complete genome sequence of Lentilactobacillus buchneri subsp. silagei MGR2-32 isolated from guinea grass silage in Okinawa, Japan.

The genome sequence of Lentilactobacillus buchneri subsp. silagei MGR2-32, isolated from guinea grass silage, is 2,540,137 bp, has a GC content of 44%, and contains 2,393 predicted protein-coding genes. Pairwise average nucleotide identity and digital DNA-DNA hybridization values between MGR2-32 and the type strain were 99.75% and 99.90%, respectively.

Classic human astrovirus 4, 8, MLB-3, and likely new genotype 5 sublineage in stool samples of children in Nigeria.

Human astrovirus (HAstV) is a nonenveloped RNA virus and has been implicated in acute gastroenteritis among children and elderly. However, there exists a substantial dearth of information on HAstV strains circulating in Nigeria. Viral-like particles were purified from archived 254 stool samples of children with acute flaccid paralysis between January and December 2020 from five states in Nigeria, using the NetoVIR protocol. Extracted viral RNA and DNA were subjected to a reverse transcription step and subsequent random polymerase chain reaction amplification. Library preparation and Illumina sequencing were performed. Using the virome paired-end reads pipeline, raw reads were processed into genomic contigs. Phylogenetic and pairwise identity analysis of the recovered HAstV genomes was performed. Six near-complete genome sequences of HAstV were identified and classified as HAstV4 (n = 1), HAstV5 (n = 1), HAstV8 (n = 1), and MLB-3 (n = 3). The HAstV5 belonged to a yet unclassified sublineage, which we tentatively named HAstV-5d. Phylogenetic analysis of open reading frames 1a, 1b, and 2 suggested recombination events inside the MAstV1 species. Furthermore, phylogenetic analysis implied a geographic linkage between the HAstV5 strain from this study with two strains from Cameroon across all the genomic regions. We report for the first time the circulation of HAstV genotypes 4, 8, and MLB-3 in Nigeria and present data suggestive for the existence of a new sublineage of HAstV5. To further understand the burden, diversity, and evolution of HAstV, increased research interest as well as robust HAstV surveillance in Nigeria is essential.

Fish feed composition by high-throughput sequencing analysis: Parasite risk assessment

The use of wild small fish species as feed for aquaculture has clearly an economic incentive by speeding the growth of farmed species. Since feed ingredients are sourced from wild fisheries the farmed species could contain natural contaminants which may introduce food safety concerns. In this study, we used High-Throughput Sequencing (HTS) to explore the whole DNA profile of ten dry commercial feeds commonly used by Spanish fish farming companies. The feeds were mainly made of species within the genus Sprattus, Ammodytes and Clupea, and vegetables of the genus Triticum. In the feeds, DNA sequences of parasitic nematodes of fishes (˂1 % total OTUs) were also identified. A taxonomic assignment of query sequences, using a phylogeny-based approach, estimation of pairwise nucleotide identities within and between sequence groups and haplotype network analysis, allow assign short query sequences to the species Phocanema krabbei (Anisakidae) and Hysterothylacium aduncum (Rhaphidascarididae). Both species were identified as ingredient in two and six fish feeds, respectively. This result is of highly concern regarding dietetic recommendations to sensitized patients to anisakids, considering the growing evidence on the possible allergenic potential of both genera, and the recent data on the transfer of anisakid heat-resistant allergens from fishmeal to farm and aquaculture animals.