Explore the vast range of titles available.

Astronotus ocellatus, commonly called the oscar, is one of the popular cichlids among aquarium hobby. The present study deals with the development and characterization of a new cell line from caudal fin of A. ocellatus. The cell line was cultured in Leibovitz’s L−15 medium supplemented with 10% fetal bovine serum at 28 °C. The optimum temperature and FBS concentration for cell growth were tested with temperature ranges from 20 to 37 °C and FBS concentrations of 5–20% at 28 °C. The Astronotus ocellatus fin cell line has been subcultured 45 times since its development and the modal chromosome number (2n) is 48. The cell line is composed mainly of epithelial cells as confirmed by immunocytological technique using anti-cytokeratin antibodies. The cell line was cryopreserved at different passage levels and the revival efficiency showed 80% survival rate. Partial sequence amplification and sequencing of two genes, mitochondrial 16S ribosomal RNA and cytochrome oxidase I, confirmed the origin of cell line. The cell line did not show Mycoplasma contamination. The cells showed good transfection efficiency when transfected with 2 μg of pAcGFP1-N1 expression vector. The extracellular products of fish bacterial pathogens viz., Aeromonas hydrophila and A. caviae, were cytotoxic to AOF cells but were not susceptible to Cyprinid herpes virus 2. The development of AOF cell line will have significant applications in fish virology and will prove useful to isolate pathogens in the event of sudden viral disease outbreak and for the development of vaccines and diagnostic kits.

Clarias dussumieri , a near threatened freshwater catfish, is endemic to peninsular India and has aquaculture potential. Unlike its sister species, C. magur , the male fish needs not be sacrificed during captive breeding. Thus, the generation of genomic information of this species becomes significant for effective genome mining through the bioprospecting of novel genes for important production traits. In this study, the genome assembly was undertaken to address this gap by generating high quality chromosome level genome assembly using PacBio long reads and Hi-C scaffolding. The total assembled genome was found to be 918.72 Mb in size and showed 95.23% completeness. Its characterization exhibited 41.46% repeats, 1,174,725 SSRs and 25,369 predicted genes with functional annotations. The Single copy orthologs analysis placed C. dussumieri in a distinct position with C. magur . The comprehensive genomic information offers resources for comparative genomics with other Clarias species for improvement of economic traits.

Spanish mackerel S. commerson belonging to family Scombridae, represent a group of highly commercial marine fisheries with an ever-growing demand world over. Analysing the genetic diversity of this species is of utmost importance and necessary for conservation purposes. Microsatellites are molecular tools with advantages that are ideal for population analyses. This study provides the first multiplex panel set of species-specific microsatellite loci for S. commerson that can be applied when assessing both intra- and inter population genetic variation. Microsatellite marker panels were developed in S. commerson , using Third Generation Sequencing technology in PacBio RSII, based on Single-Molecule Real-Time (SMRT) . Thirty- two microsatellite loci were isolated and characterized for S. commerson , by genotyping 20 individuals each obtained from the Kochi and Veraval in the Arabian sea and Chennai along Bay of Bengal coast (n = 3). The number of alleles per locus in S. commerson varied from 4 to 17, while the mean observed and expected heterozygosities ranged from 0.656 to 0.753. The Polymorphic Information Content (PIC) were highly informative, 85% loci with PIC value 0 > 0.75. This suite of markers provides the first species specific nuclear multiplex microsatellite marker panels (32 loci) for S. commerson and thus allows assessment of different populations structures of the species across its distribution range, with more specificity. These newly developed loci have also been validated for cross transferability in another scomberid fish Scomberomorus guttatus .

A new species of the genus Pangasius, is described based on 17 specimens collected from the Cauvery River, India. It can be distinguished from its sister species from South and Southeast Asia, by its widely placed, small and rounded vomerine and palatine tooth plates, longer maxillary and mandibular barbels, greater vertebrae count 50 (vs. 44–48), and smaller caudal peduncle depth (6.5–8.2% SL vs. 9.89–13.09% SL). The tooth plates of the new species closely resembles that of Pangasius macronema but can be clearly distinguished from the latter by having lesser gill rakers (16–19 vs. 36–45); a smaller eye (2.4–4.4% SL vs. 5.2–9.6% SL); and larger adipose-fin base (1.5–2.9% SL vs. 0.1–1.2% SL). The mitochondrial cytochrome c oxidase (COI) gene sequence of the new species shows the genetic divergence of 3.5% and 5.1% from P. pangasius and P. silasi respectively, the two sister species found in South Asia and India. The species delimitation approaches, Poisson Tree Processes (PTP) and assemble species by automatic partitioning (ASAP) clearly resolved that the P . icaria is distinct from its sister species. Phylogenetic position of the species with its sister species was evaluated using maximum likelihood and Bayesian analysis. The discovery of this previously unknown species of genus Pangasius from the Cauvery River of peninsular India indicates important biogeographical insight that this genus migrated till the southern division of Western Ghats.

The pigeonpea urease was immobilized on agar, a common gelling substance. The tablet strips were used as moulds to cast agar tablets of uniform shape and size. The time and temperature of solidification of agar was 6 min and 44 °C, respectively. The 5 % agar (w/v) and 0.019 mg protein/agar tablet yielded an optimum immobilization of 51.7%. The optimum pH was shifted through 0.2 U (from 7.3 to 7.5) towards basic side upon immobilization. The optimum temperature of soluble and immobilized urease was 30 °C and 60 °C, respectively, showing the improvement in thermal stability of urease. There was an increase in K(m) from 3.23 to 5.07 mM after immobilization. The half-lives of soluble and immobilized urease were 21 and 53 days, respectively, at pH 7.3 and 4 °C. The urea was estimated in different blood samples with the help of immobilized urease and the results were consistent with those from clinical pathology laboratory through an autoanalyzer.

Background Hemibagrus punctatus (Jerdon, 1849) is a critically endangered bagrid catfish endemic to the Western Ghats of India, whose population is declining due to anthropogenic activities. The current study aims to compare the mitogenome of H. punctatus with that of other Bagrid catfishes and provide insights into their evolutionary relationships. Methods and Results Samples were collected from Hemmige Karnataka, India. In the present study, the mitogenome of H . punctatus was successfully assembled, and its phylogenetic relationships with other Bagridae species were studied. The total genomic DNA of samples was extracted following the phenol–chloroform isoamyl alcohol method. Samples were sequenced, and the Illumina paired-end reads were assembled to a contig length of 16,517 bp. The mitochondrial genome was annotated using MitoFish and MitoAnnotator (Iwasaki et al ., 2013). A robust phylogenetic analysis employing NJ (Maximum composite likelihood) and ASAP methods supports the classification of H. punctatus within the Bagridae family, which validates the taxonomic status of this species. In conclusion, this research enriches our understanding of H. punctatus mitogenome, shedding light on its evolutionary dynamics within the Bagridae family and contributing to the broader knowledge of mitochondrial genes in the context of evolutionary biology. Conclusions The study’s findings contribute to a better understanding of the mitogenome of H . punctatus and provide insights into the evolutionary relationships within other Hemibagrids.

Goldfish is one of the preferred ornamental fish which is highly susceptible to cyprinid herpesvirus-2 (CyHV-2) infection. The present study aimed to analyse immune gene expression in a co-culture of CyHV-2-sensitized goldfish peripheral blood leukocytes (PBLs) with CyHV-2-infected fantail goldfish fin cell lines (FtGF). Goldfish were sensitized with intraperitoneal TCID50 dose (107.8±0.26/mL) of CyHV-2. After 2 weeks, PBLs were collected and co-cultured with CyHV-2-infected FtGF cells keeping both uninfected FtGF cells and PBL control groups. After 2 days of co-culture, WST-1 assay for cell proliferation was performed at 450 nm during the 2nd, 4th and 6th days of co-culture. The results showed a significant increase (p < 0.05) in cell density in CyHV-2-infected PBL and virus-infected FtGF cells during the 4th day post co-culture which confirmed effector cell generation. Expressions of few immune genes were checked taking RNA samples of CyHV-2-induced PBLs post co-culture with infected FtGF cells along with uninfected FtGF cells as control group at different time periods (2nd, 4th and 6th days) in triplicate. The results indicated increased expression of CD8α, IFNγ, b2m, MHC I, LMP 7, IL-10, IL-12 and GATA3 except Tapasin. From the above study, we concluded that goldfish showed both Th1- and Th2-mediated immune responses to CyHV-2. The current findings support the scope for further vaccine development against CyHV-2 for goldfish.

The study documents the embryonic and larval development of Clarias dussumieri , a Near-Threatened, cultivable, and highly valued food fish endemic to the Western Ghats. Induced breeding facilitated detailed observation of developmental stages using light microscopy. Unfertilized eggs measured 1.5 ± 0.02 mm in diameter and enlarged to 1.7 ± 0.10 mm after fertilization (∼13% increase). The first cleavage occurred at 00:36 ± 00:02 h, reaching 64 cells by 01:35 ± 00:06 h. Epiboly progressed from 30% at 03:20 ± 00:10 h to 50% at 04:30 ± 00:05 h and 90% at 05:50 ± 00:10 h; neurulation was evident by 07:40 ± 01:10 h and somites by 11:08 ± 01:26 h. The first heartbeat appeared during the pharyngula period (17:25 ± 01:30 h), and hatching occurred at 25:30 ± 01:30 h at 26–27°C. Hatched larvae were 4.2 ± 0.02 mm total length, observed few melanophores by 12 h, conspicuous eye pigmentation by 24 h, and body pigmentation spreading by day 2 (5.90 ± 0.04 mm).The yolk sac was fully absorbed by 72 ± 2.50 h post-hatching, marking the onset of exogenous feeding. By day 4 (pre-flexion), larvae reached 7.1 ± 0.02 mm; initial notochord flexion began around day 7 and post-flexion from day 10, with juvenile-like morphology evident by day 25 (15.27–17.80 mm). The standardized timelines and measurements provide a baseline for hatchery practice and conservation aquaculture of C. dussumieri , supporting protocol refinement for improving survival and growth under controlled conditions

Black collared yellow catfish, Horabagrus nigricollaris , an endangered endemic catfish of the River Chalakudy, Kerala, cherished by the locals is one of the most sought-after ornamental fish. Due to the limited range of distribution and rarity, H. nigricollaris needs to be conserved in situ. Captive breeding, embryonic development, nursery rearing, and restocking of the species were done for the first time ever as part of conservation efforts. A total of 10 breeding trials with a sex ratio of 1:1 was conducted between 2022 and 2023. Half of brooders spontaneously spawned after receiving an injection of WOVA-FH hormone (1.0 ml/kg body weight) with a latency period of 11.3 ± 0.37 h. Mean spawning fecundity was 1740 ± 193 with fertilization rate of 68.7 ± 2.4%, hatching rate of 71.3 ± 1.9%, and survival rate of 88.1 ± 3.2%. The fertilized eggs were adhesive and elliptical, golden yellow in color with a diameter of 2.1 ± 0.02 mm. The first mitotic cleavage occurs at 35 min post-fertilization (pf) and morula, blastula, and gastrula stages were completed at approximately 3.50 h, 6.15 h, and 10.30 h, respectively. The incubation period was 27 ± 3 h at a temperature between 26 and 28 °C. Newly hatched larvae were transparent and light yellowish, measuring 4.4 ± 0.2 mm, with a large oval-shaped yolk sac. Yolk absorption was completed within 3 days post-hatching. The larvae were fed a systemic and overlapping diet of live and artificial feed over 30 days, resulting in an average length and weight of 20.4 ± 0.2 mm, 1.3 ± 0.1 g, and a survival rate of 56.1 ± 3.2%. About 1500 fish of 120 days old with mean length 73 ± 3.0 mm and average weight 3.2 ± 0.2 g were reintroduced into the Chalakudy River at the Vettilapara region, which is the type locality of the species, to safeguard and increase the wild population.

In India, many of the fish farmers stock 1-year-old stunted fishes (stunted yearlings) of Indian major carps (IMC) for enhancing fish production through compensatory growth, but many of them observed problems of early maturation in these fishes. Application of aromatase inhibitors for deceleration of ovarian maturation is one of the probable solutions to mitigate this issue. In the present study, a synthetic aromatase inhibitor letrozole [25 (L₂₅) and 50 (L₅₀) mg kg⁻¹ feed] and a plant-derived aromatase inhibitor, grape seed extract [100 (G₁₀₀) and 200 (G₂₀₀) mg kg⁻¹ feed], were fed to stunted yearlings of rohu (Labeo rohita) for 45 days well before the onset of breeding season. Maturation indices such as gonadosomatic index (GSI) and serum oestradiol (E) levels indicated a dose-dependent inhibition of ovarian development in the aromatase-inhibitor-treated fish. Higher dose of letrozole (GSI, 15.12 ± 0.18; E, 3.19 ± 0.42) and grape seed extract (GSI, 16.90 ± 0.40; E, 3.60 ± 0.75) were found to be more effective since control fish showed further advancement in maturation (GSI, 21.20 ± 1.10; E, 7.33 ± 0.74) during the peak breeding season (15th June). Histological observations also confirmed the results revealing a delayed initiation of ovarian development in the case of higher doses of letrozole and grape seed extracts. These results indicate the possible use of aromatase inhibitors in arresting the early maturation process in IMC.