Complete mitogenome of Ganges river dolphin, Platanista gangetica gangetica and its phylogenetic relationship with other cetaceans.

The Ganges river dolphin, Platanista gangetica gangetica is one of the endangered cetaceans. Due to increasing anthropogenic activities, it has faced a significant reduction in distribution range since the late 1800s and has even gone extinct from most of the early localities. The investigation of complete mitogenome holds significant relevance for identifying evolutionary relationships and monitoring the endangered species. Herein, we report and characterize for the first time the 16,319 bp complete mitochondrial genome of P. g. gangetica. It comprises 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA genes, and one control region (CR). The genome composition was A + T biased (59.6%) and exhibited a positive AT-skew (0.104) and negative GC-skew (- 0.384). All the genes were encoded on the heavy strand, except eight tRNAs and the ND6 gene. In the CR, an 18 bp tandem repeat sequence was observed. Our Bayesian Inference (BI) and Maximum Likelihood (ML) based phylogenetic analysis indicated that studied river dolphins were polyphyletic and the placement of Platanista was to be more basal than other river dolphins (Lipotes, Inia and Pontoporia). The pairwise genetic distance of Platanista with other cetaceans was varied, with an overall close affinity with whales. The model-based BI and ML phylogenetic analysis indicated that Platanista clustering with Ziphiidae with high to moderate supportive values (PP/BP = 98/68). The results of this study provide insights important for the conservation genetics and further evolutionary studies of the freshwater river dolphins.

Expression profile and in silico characterization of novel RTF2h gene under oxidative stress in Indian catfish, Clarias magur (Hamilton 1822).

During the investigation of genes involved in the hypoxia tolerance, novel transcript, Replication Termination Factor 2 homologue (RTF2h), was found to be differentially expressed in brain of Clarias magur (previous name, C. batrachus) whose function was still undefined. Thus, present study was aimed to examine the transcriptional response of novel RTF2h gene, for its possible involvement in hypoxia tolerance in C. magur. Novel transcripts expressed under hypoxic stress were identified from ESTs obtained from SSH libraries of C. magur. Homology analysis of novel transcript (JK487668) revealed it to have RING superfamily signature and was closely related with RTF2 homologue. To characterize the expression pattern of CmRTF2h gene in different tissues of C. magur, qRT-PCR analysis was performed which showed significant increased expression, in spleen following short-term hypoxia exposure (12 H; 2.33-fold), while after long-term hypoxia exposure, significant up-regulation was found three tissues: in spleen (6.57-fold), liver (2.31-fold) and head kidney (2.99-fold) and was down-regulated in brain (3.52-fold). Further, the consensus sequence, obtained from SSH EST sequence and transcripts from hypoxia induced transcriptome data, through multiple sequence alignments, homology modeling and phylogentic analysis together, confirmed it as a novel CmRTF2h gene. In-silico protein-protein interaction and docking studies suggested its closely related function to that of RTF2. The present study reports the expression pattern of CmRTF2h under hypoxia. The up-regulated expression of CmRTF2h under hypoxic conditions may contribute to defense mechanism against induced DNA damage, which in turn may of adaptive significance for hypoxia tolerance in C. magur.

Hypoxia induced altered expression of heat shock protein genes (Hsc71, Hsp90α and Hsp10) in Indian Catfish, Clarias batrachus (Linnaeus, 1758) under oxidative stress.

Heat shock proteins (Hsps) are typically associated with stress response and tolerance. The Indian catfish, Clarias batrachus, is a freshwater air-breathing hypoxia tolerant teleost and is potentially important catfish species for aquaculture and for its economic value as food. The present study aimed at determining the transcriptional response of three Hsps, CbHsc71, CbHsp90α and CbHsp10 in hypoxia tolerant Indian catfish, C. batrachus, under experimental and natural hypoxia. The expression profile of above three genes were studied under different periods of hypoxia, through qRT-PCR. Primers were designed from ESTs obtained through SSH libraries constructed from hypoxia treated fishes. The Hsp10 ESTs and deduced protein was in silico characterized for its ORF and for its physical and chemical properties, respectively, using GeneScan, blastp, scanprosite, superfamily and other softwares. A phylogenetic tree was constructed based on deduced amino acid sequences of Hsc71, Hsp90α, Hsp90ß of Homo sapiens and other fishes along with CbHsp10 protein in MEGA4. The deduced protein sequences of CbHsp10 was found to have characteristic Hsp10 family signatures, and it is proposed for inclusion of methionine in the consensus sequences of Hsp10 family signature, after the "proline" residue. At transcription level, these genes were found to be differentially regulated under hypoxia stress, in different tissues of C. batrachus. The CbHsc71 and CbHsp90α were up-regulated after short and long-term hypoxia, whereas CbHsp10 was significantly down-regulated after short-term hypoxia. The differential expression of these Hsps may play a role in protection and survival under hypoxia induced oxidative stress in C. batrachus.

Multifocal osteonecrosis due to the synergistic impact of inherited thrombophilia, autoimmunity and pregnancy: a case report.

Multifocal osteonecrosis is a rare entity which can lead to bone fragility, fractures and considerable morbidity. The objective of this report is to describe the presentation, evaluation and management of a case of multifocal osteonecrosis. A 34-year-old lady presented with multiple fractures and bone pain which was exacerbated during pregnancy. She was found to have osteonecrosis involving multiple sites. Investigation revealed that she had an undefined autoimmune condition with antinuclear antibody and anti-Ro (SS-A) positivity, not fulfilling criteria for diagnosis of Sjogren syndrome. She had low Protein S levels for age and gender (confirmed on 2 occasions 12 weeks apart outside pregnancy). She had a novel variant in the PROS1 gene (NM_000313.4:c.1513G>A; p.Gly505Ser) which is associated with heterozygous Protein S (PS) deficiency. She had a good response to treatment with anticoagulation. The combination of inherited thrombophilia, autoimmunity and the thrombophilic state induced by pregnancy probably contributed to the severe phenotype in this patient. The variant was identified in the Lamin G1 domain, which is instrumental in PS binding to tissue factor pathway inhibitor and C4 binding protein, thus playing a role in both the coagulation and complement pathway, and could explain the coexistence of autoimmunity with thrombophilia. This variant is present in 0.034% of South Asians in the gnomAD population database, and may represent an important cause of inherited thrombophilia in this group.

Population genetics of the critically endangered three-striped turtle, Batagur dhongoka, from the Ganga river system using mitochondrial DNA and microsatellite analysis.

The three-striped roofed (Batagur dhongoka) is a semi-aquatic turtle that belongs to family Geoemydidae. Due to anthropogenic pressure, it has been facing an intense decline of over 80% in its distribution range in the past 50 years. It is considered as 'Critically Endangered' so effective conservation strategies are needed to protect the species by determining their genetic diversity and population genetic structure. This study investigates the genetic diversity, population structure and demographic pattern of B. dhongoka from two Turtle Rescue and Rehabilitation Centre established near Ganga river using mitochondrial cytochrome b (Cyt b: 1140 bp) ; control region (CR: 451 bp) and ten nuclear microsatellite loci. mtDNA results show low levels of nucleotide diversity (π = 0.0022) in B. dhongoka haplotypes and provide evidence for a low substitution rate. The demographic pattern estimated by the Bayesian skyline plot (BSP) analysis indicates historical stability followed by growth in the effective population size, with a recent reduction in population size from ~ 2 thousand years ago. The microsatellite findings show a moderate level of observed heterozygosity (Ho: 0.49). Bayesian-based clustering analysis revealed weak genetic structures in B. dhongoka and presence of admixed assignations suggesting close genetic relationships. These findings shed light on B. dhongoka's genetic status and underline the necessity of comprehensive rehabilitation and relocation programs and conservation and management techniques to ensure the species' long-term survival. In order to ensure the effective protection and conservation of B. dhongoka, the Government of India has taken a proactive measure by incorporating it into Schedule I of the Wildlife (Protection) Act, 1972, as amended in 2022.

Evaluation of the effect of longitudinal connectivity in population genetic structure of endangered golden mahseer, Tor putitora (Cyprinidae), in Himalayan rivers: Implications for its conservation.

In many aquatic species, alteration of habitats and human-induced barriers shape the population's genetic structure in rivers with longitudinal connectivity. The golden mahseer, Tor putitora (GM) is an endangered and sensitive cyprinid species. It is considered an indicator of a healthy freshwater ecosystem and is found in cold-water habitats. Therefore, it is crucial to understand how longitudinal connectivity and anthropogenic factors affect the diversity and population genetic structure of GM. The population genetic structure, gene flow and demography of the GM in four Himalayan rivers were investigated by mitochondrial cytochrome b gene (cyt b) as well as microsatellite genotyping. The results showed overall high mtDNA diversity (hd: 0.795) couple with low nucleotide diversity (π: 0.0012) in all GM populations. We also found significant levels of observed heterozygosity (ranging from 0.618 to 0.676), with three genetic clusters. The mtDNA and microsatellite analysis suggested that there are close genetic relationships between the Bhagirathi and Ganga populations; whereas, significant level of genetic differentiation was observed with that of Alaknanda and Yamuna populations. Haplotype distribution, unimodal distribution graph and results of the neutrality test indicated a sign of recent population growth in the GM population. Analysis of molecular variance (AMOVA) and spatial molecular variance (SAMOVA) revealed existence of genetic structures in GM populations. In addition, spatial genetic analysis detected a significant correlation between the pairwise genetic and geographical distances for the entire study area (Mantel test, rM = 0.126; P = 0.010). Considering the significant level of heterozygosity, high rate of unidirectional migration and the intra-population structuring in Alaknanda and Yamuna, it is crucial to propose an effective conservation plan for the GM populations. In general, dams obstruct continuous water flow and create isolated microhabitats. Therefore, we recommend the establishment of microscale protected areas near GM breeding sites and construction of fish pass to maintain the genetic connectivity of fish species that enhance viable populations.

Sequencing and characterization of the complete mitochondrial genome of Mishmi takin (Budorcas taxicolor taxicolor) and comparison with the other Caprinae species.

Mishmi takin (Budorcas taxicolor taxicolor) is an endangered and least studies species. We sequenced and annotated a 16,584 bp long complete mitogenome of Mishmi takin (B. t. taxicolor). It was encoded by 37 genes: 13 Protein-Coding Genes (PCGs), two ribosomal RNA genes, 22 transfer RNA, and non-coding control region. All tRNA genes show a typical secondary cloverleaf structure, except tRNAser(AGY) in which dihydrouridine arm did not form a stable structure. We observed 82 bp nucleotide deletions in the control region of Mishmi takin. The overall analysis of 13 PCGs, two rRNA and 22 tRNA of Mishmi takin indicates its close relationship with the B. t. tibetana than the B. t. bedfordi. The overall genetic similarity indicated that all takin species is closely related to the P. nayaur than the C. ibex and Ovibos moschatus. This study provides a useful resource for further studies on conservation and population genetics of Budorcas.

Muscle transcriptome resource for growth, lipid metabolism and immune system in Hilsa shad, Tenualosa ilisha.

The information on the genes involved in muscle growth, lipid metabolism and immune systems would help to understand the mechanisms during the spawning migration in Hilsa shad, which in turn would be useful in its future domestication process. The primary objective of this study was to generate the transcriptome profile of its muscle through RNA seq. The total RNA was isolated and library was prepared from muscle tissue of Tenualosa ilisha, which was collected from Padma River at Farakka, India. The prepared library was then sequenced by Illumina HiSeq platform, HiSeq 2000, using paired-end strategy. A total of 8.68 GB of pair-end reads of muscle transcriptome was generated, and 43,384,267 pair-end reads were assembled into 3,04,233 contigs, of which 23.99% of assembled contigs has length ≥ 150 bp. The total GO terms were categorised into cellular component, molecular function and biological process through PANTHER database. Fifty-three genes related to muscle growth were identified and genes in different pathways were: 75 in PI3/AKT, 46 in mTOR, 76 in MAPK signalling, 24 in Janus kinase-signal transducer and activator of transcription, 45 in AMPK and 27 in cGMP pathways. This study also mined the genes involved in lipid metabolism, in which glycerophospholipid metabolism contained highest number of genes (32) and four were found to be involved in fatty acid biosynthesis. There were 58 immune related genes found, in which 31 were under innate and 27 under adaptive immunity. The present study included a large genomic resource of T. ilisha muscle generated through RNAseq, which revealed the essential dataset for our understanding of regulatory processes, specifically during the seasonal spawning migration. As Hilsa is a slow growing fish, the genes identified for muscle growth provided the basic information to study myogenesis. In addition, genes identified for lipid metabolism and immune system would provide resources for lipid synthesis and understanding of Hilsa defense mechanisms, respectively.

Hypoxia influences expression profile of Pleckstrin homology-like domain, family A, member 2 in Indian catfish, Clarias batrachus (Linnaeus, 1758): a new candidate gene for hypoxia tolerance in fish.

Several physiologically important genes were found to be regulated by hypoxia at the transcriptional level. The Pleckstrin homology-like domain, family A, member 2 (PHLDA2) gene was previously identified as an imprinted gene. The present study was aimed to determine the structure of complete cDNA and the deduced protein of PHLDA2 along with analysing the changes in its mRNA expression in Clarias batrachus tissues under hypoxic conditions. The complete cDNA of CbPHLDA2 gene consisted of 1009 nucleotides with an open reading frame of 417 nucleotides. The deduced CbPHLDA2 protein of 139 amino acids shared high homology with PHLD2A of other fishes as well as that of vertebrates. Importantly, a single amino acid (asparagine/lysine) insertion was identified in the PH domain of CbPHLDA2 and other fishes, which was absent in other vertebrates studied. Furthermore, under normoxic conditions, CbPHLDA2 was constitutively expressed with varying levels in analysed tissues. Short- and long-term hypoxia exposure resulted in significant changes in the expression of CbPHLDA2 in liver, spleen, head kidney, brain and muscle in a time-dependent manner. The results suggested that CbPHLDA2 might play an important role for adaptive significance under hypoxia.