Discovery of a new species of Adder’s tongue fern from India with comparative analysis of morphological and molecular attributes

Eusporangiate fern genus Ophioglossum L. is commonly known as Adder’s tongue fern as its fertile frond gives the appearance of snake tongue. A new species in this fern genus, O. trilokinathii belonging to Ophioglossaceae family has been discovered from the plateau region of Rajasthan State of northwestern India. The new species can be distinguished from other taxa of this genus by its smaller habit, subglobose-tuberous rhizome, basipetal emergence of young roots, aggregation of old decaying roots on rhizome apex, fertile stalk as well as spike short and thick, trophophylls in rosette, ovate or orbicular and a unique sporoderm sculpture pattern under SEM having broad reticulations with thick and raised muri enclosing large hexagonal or irregular areas on the distal and proximal faces of the spores hitherto unreported in any of the presently known taxa of Ophioglossum. In addition, comparative study of stomatal structure, foliar anatomy and nucleotide sequence data of its three chloroplast DNA markers (trnL-F, rbcL and psbA-trnH) was carried out. In view of all the attributes including habitat, ecology, morphology, foliar anatomy, stomatal features, palynology and molecular phylogenetic data, the present study suggests that the Ophioglossum specimen collected from plateau region of Rajasthan represents a hitherto undescribed species thereby warranting its establishment as O. trilokinathii sp. nov. A detailed comparative account of the new taxon with its allied species has also been provided.

Quantitative monitoring of nucleotide sequence data from genetic resources in context of their citation in the scientific literature

Background Linking nucleotide sequence data (NSD) to scientific publication citations can enhance understanding of NSD provenance, scientific use, and reuse in the community. By connecting publications with NSD records, NSD geographical provenance information, and author geographical information, it becomes possible to assess the contribution of NSD to infer trends in scientific knowledge gain at the global level. Findings We extracted and linked records from the European Nucleotide Archive to citations in open-access publications aggregated at Europe PubMed Central. A total of 8,464,292 ENA accessions with geographical provenance information were associated with publications. We conducted a data quality review to uncover potential issues in publication citation information extraction and author affiliation tagging and developed and implemented best-practice recommendations for citation extraction. We constructed flat data tables and a data warehouse with an interactive web application to enable ad hoc exploration of NSD use and summary statistics. Conclusions The extraction and linking of NSD with associated publication citations enables transparency. The quality review contributes to enhanced text mining methods for identifier extraction and use. Furthermore, the global provision and use of NSD enable scientists worldwide to join literature and sequence databases in a multidimensional fashion. As a concrete use case, we visualized statistics of country clusters concerning NSD access in the context of discussions around digital sequence information under the United Nations Convention on Biological Diversity.

A computational screen for alternative genetic codes in over 250,000 genomes

The genetic code has been proposed to be a 'frozen accident', but the discovery of alternative genetic codes over the past four decades has shown that it can evolve to some degree. Since most examples were found anecdotally, it is difficult to draw general conclusions about the evolutionary trajectories of codon reassignment and why some codons are affected more frequently. To fill in the diversity of genetic codes, we developed Codetta, a computational method to predict the amino acid decoding of each codon from nucleotide sequence data. We surveyed the genetic code usage of over 250,000 bacterial and archaeal genome sequences in GenBank and discovered five new reassignments of arginine codons (AGG, CGA, and CGG), representing the first sense codon changes in bacteria. In a clade of uncultivated Bacilli, the reassignment of AGG to become the dominant methionine codon likely evolved by a change in the amino acid charging of an arginine tRNA. The reassignments of CGA and/or CGG were found in genomes with low GC content, an evolutionary force which likely helped drive these codons to low frequency and enable their reassignment.

A rare moss Cynodontium suecicum (Rhabdoweisiaceae, Bryophyta) on the Barents Sea coast of the Kola Peninsula: morphological and molecular study

Specimens of the rare species Cynodontium suecicum (Rhabdoweisiaceae, Bryophyta) were collected near Drozdovka Bay on the Barents Sea coast of the Kola Peninsula (Russia) in 2016. They were compared with samples of C. suecicum from the Teriberka area (also the coast of the Barents Sea) gathered in 1977 by R. N. Schljakov. The morphological features of both groups of samples were studied, and nucleotide sequence data for ITS1-2 nrDNA and trnL-F cpDNA were obtained. Molecular analysis suggested C. suecicum as a hybrid that inherited cytoplasmic DNA from C. tenellum and nuclear DNA from Kiaeria blyttii. Taking into account the rather clear morphological delimitation against other species, combined with the stability of genetic characters, we believe that S. suecicum should be retained as a species-level taxon.

FAIR enough? A perspective on the status of nucleotide sequence data and metadata on public archives

Knowledge derived from nucleotide sequence data is increasing in importance in the life sciences, as well as decision making (mainly in biodiversity policy). Metadata standards have been established to facilitate sustainable sequence data management according to the FAIR principles (Findability, Accessibility, Interoperability, Reusability). Here, we review the status of metadata available for raw read Illumina amplicon and whole genome shotgun sequencing data derived from ecological metagenomic material that are accessible at the European Nucleotide Archive (ENA), as well as the compliance of the primary sequence data (fastq files) with data submission requirements. While overall basic metadata, such as geographic coordinates, were retrievable in 98% of the cases for this type of sequence data, interoperability was not always ensured and other (mainly conditionally) mandatory parameters were often not provided at all. Metadata standards, such as the 'Minimum Information about any(x) Sequence (MIxS)', were only infrequently used despite a demonstrated positive impact on metadata quality. Furthermore, the sequence data itself did not meet the prescribed requirements in 31 out of 39 studies that were manually inspected. To tackle the most immediate needs to improve FAIR sequence data management, we provide a list of minimal suggestions to researchers, research institutions, funding agencies, reviewers, publishers, and databases, that we believe might have a potentially large positive impact on sequence data and metadata FAIRness, which is crucial for further research and its derived applications.

Hedyotis hamiguitanensis (Rubiaceae: Spermacoceae), a new species from Mt. Hamiguitan, Davao Oriental, Philippines and its systematic position in Hedyotis

Hedyotis hamiguitanensis, from Mt. Hamiguitan, Davao Oriental, Philippines, is described, illustrated, and compared with two similar species, H. whiteheadii and H. schlechteri. This species is distinguished from congeneric Philippine species by its 5–12 cm long, compound, umbellate inflorescences, pendulous flowers, lanceolate to oblanceolate, thick, scabrid leaf blades with revolute margins. Its phylogenetic systematic position within the tribe Spermococeae is determined with a phylogenetic analysis using chloroplast (rps16, petD) and nuclear ribosomal (ITS, ETS) nucleotide sequence data.

Enabling metagenomic surveillance for bacterial tick-borne pathogens using nanopore sequencing with adaptive sampling

Technological and computational advancements in the fields of genomics and bioinformatics are providing exciting new opportunities for pathogen discovery and surveillance. In particular, single-molecule nucleotide sequence data originating from Oxford Nanopore Technologies (ONT) sequencing platforms can be bioinformatically leveraged, in real-time, for enhanced biosurveillance of a vast array of zoonoses. The recently released nanopore adaptive sampling (NAS) pipeline facilitates immediate mapping of individual nucleotide molecules (i.e., DNA, cDNA, and RNA) to a given reference as each molecule is sequenced. User-defined thresholds then allow for the retention or rejection of specific molecules, informed by the real-time reference mapping results, as they are physically passing through a given sequencing nanopore. Here, we show how NAS can be used to selectively sequence entire genomes of bacterial tick-borne pathogens circulating in wild populations of the blacklegged tick vector, Ixodes scapularis. The NAS method provided a two-fold increase in targeted pathogen sequences, successfully enriching for Borrelia (Borreliella) burgdorferi s.s.; Borrelia (Borrelia) miyamotoi; Anaplasma phagocytophilum; and Ehrlichia muris eauclairensis genomic DNA within our I. scapularis samples. Our results indicate that NAS has strong potential for real-time sequence-based pathogen surveillance.

A computational screen for alternative genetic codes in over 250,000 genomes

The genetic code has been proposed to be a "frozen accident", but the discovery of alternative genetic codes over the past four decades has shown that it can evolve to some degree. Since most examples were found anecdotally, it is difficult to draw general conclusions about the evolutionary trajectories of codon reassignment and why some codons are affected more frequently. To fill in the diversity of genetic codes, we developed Codetta, a computational method to predict the amino acid decoding of each codon from nucleotide sequence data. We surveyed the genetic code usage of over 250,000 bacterial and archaeal genome sequences in GenBank and discovered five new reassignments of arginine codons (AGG, CGA, and CGG), representing the first sense codon changes in bacteria. In a clade of uncultivated Bacilli, the reassignment of AGG to become the dominant methionine codon likely evolved by a change in the amino acid charging of an arginine tRNA. The reassignments of CGA and/or CGG were found in genomes with low GC content, an evolutionary force which likely helped drive these codons to low frequency and enable their reassignment.

CALLIPHORIDAE (REVIEW)

The Calliphoridae family attracts many researchers in the phylogeny of myiasis in this family. Nevertheless, even after more than 50 years of research of the phylogenetic relationships among Calliphoridae subfamilies, the origin of myiasis remains unclear. By studying the peculiarities of the ecology of blue-green meat flies, and their adaptation to various habitats, it was found that the transition to facultative parasitism at the larval stage could occur in several ways, and was accompanied by the formation of viviparity. The larval parasitism of Calliphoridae on birds developed as a tendency of evolution. Larvae of the genus Protocalliphora, began feeding on blood of birds, and larvae of the species of the genus Trypocalliphora feed on the host tissues causing myiasis and the death of chicks. In order to elucidate the problem, we constructed three phylogenetic trees using nucleotide sequence data from cytochrome oxidase subunit one gene (COI), representing a mitochondrial conservative gene, and nuclear 28S subunit of ribosomal RNA gene (28S rRNA) in order to interpret the evolutionary profile of myiasis in the family Calliphoridae. Comparative analysis of the phylogenetic trees shows that the habit of obligatory myiasis originated independently more than five times among different calliphorid taxa in the course of evolutionary history. The inclusion of other myiasis-causing families (Oestridae, Gastrophilidae, and Sarcophagidae) along with fundamental life-history studies that deal with biology, physiology, feeding behavior and host specificity in addition to phylogenetic analysis could provide a more accurate answer to the origin of myiasis