N.K. Chadha

p53 dependent apoptotic cell death induces embryonic malformation in Carassius auratus under chronic hypoxia.

Hypoxia is a global phenomenon affecting recruitment as well as the embryonic development of aquatic fauna. The present study depicts hypoxia induced disruption of the intrinsic pathway of programmed cell death (PCD), leading to embryonic malformation in the goldfish, Carrasius auratus. Constant hypoxia induced the early expression of pro-apoptotic/tumor suppressor p53 and concomitant expression of the cell death molecule, caspase-3, leading to high level of DNA damage and cell death in hypoxic embryos, as compared to normoxic ones. As a result, the former showed delayed 4 and 64 celled stages and a delay in appearance of epiboly stage. Expression of p53 efficiently switched off expression of the anti-apoptotic Bcl-2 during the initial 12 hours post fertilization (hpf) and caused embryonic cell death. However, after 12 hours, simultaneous downregulation of p53 and Caspase-3 and exponential increase of Bcl-2, caused uncontrolled cell proliferation and prevented essential programmed cell death (PCD), ultimately resulting in significant (p<0.05) embryonic malformation up to 144 hpf. Evidences suggest that uncontrolled cell proliferation after 12 hpf may have been due to downregulation of p53 abundance, which in turn has an influence on upregulation of anti-apoptotic Bcl-2. Therefore, we have been able to show for the first time and propose that hypoxia induced downregulation of p53 beyond 12 hpf, disrupts PCD and leads to failure in normal differentiation, causing malformation in gold fish embryos.

Histological Alterations in the Hepatopancreas and Growth Performance of Pacific White Shrimp (Litopenaeus vannamei, Boone 1931) Reared in Potassium Fortified Inland Saline Ground Water

1 Aquaculture Division, Central Institute of Fisheries Education, Off Yari Road, PanchMarg, Mumbai – 400 061, MS, India 2 Soil and Land use Survey of India 3 Central Institute of Fisheries Education, Off Yari Road, PanchMarg, Mumbai – 400 061, MS, India 4 Fish Nutrition, Biochemistry and Physiology Division, Central Institute of Fisheries Education, Off Yari Road, PanchMarg, Mumbai – 400 061, MS, India *Corresponding author

Inhibin anti-peptide antibody macromolecule: An approach to improve fecundity in Clarias batrachus

Inhibins are members of the transforming growth factor beta (TGFβ) superfamily known to regulate ovarian functions through stimulation of the hypothalamo-pituitary-gonadal axis. In the present study, we aimed to design a species-specific inhibin-α chimeric peptide (ICP) and evaluate the effect of immunoneutralization using anti-ICP antisera to enhance the reproductive performance in female Clarias batrachus. Injection of anti-ICP antisera caused a significant increase in the number of oocytes at a medium dose (200 μl) in comparison to high dose (400 μl) and control (normal rabbit serum). Histological observations confirmed the dose-dependent advancement in oocyte maturation. Furthermore, anti-ICP antisera treated groups exhibited a significant increase in the serum concentrations of follicle stimulating hormone (FSH) and 17β-estradiol (E2) hormones. The anti-ICP antisera decreased the mRNA expression levels of inhibin-α while stimulated the transcript levels of inhibin-βA, FSHβ, CYP 19a1, 3β-HSD and StAR respectively in a dose-dependent manner. Collectively, these findings indicate that anti-ICP antibody macromolecules modulate the endogenous reproductive hormonal secretion and enhance oocyte quality and quantity in female C. batrachus. This is the first report wherein antibodies against inhibins were used to promote reproductive performances and investigate the underlying molecular mechanisms in fishes.

Effect of Stocking Density on Growth and Survival of Fenneropenaeus merguiensis (de Man, 1888) Post Larvae

Shrimp, which earns huge revenue through export, is an important aquaculture commodity in India. Several studies revealed that Fenneropenaeus merguiensis, popularly known as banana shrimp, which are found throughout the Asian and Australian tropical and subtropical waters, is a promising candidate species for aquaculture (Zacharia and Kakati, 2002). F. merguiensis has attracted researchers and farmers because of certain advantages like captive breeding in pond, tolerance to low water quality, euryhaline and eurythermal nature, it’s readily availability in the wild, good performance during high stocking densities, low protein requirement, minimal size variation during grow out phase, and cheap availability of wild brooders. Above that, rearing of larvae and post larvae of F. merguiensis is comparatively easy (Hoang, 2002).

Growth and survival of marine sponges, Stylissa massa (Carter, 1887) and Liosina paradoxa (Thiele, 1899) in sea and land based culture systems

Two species of marine sponges Stylissa massa and Liosina paradoxa were cultured in cages (in situ) and in land based aquaria (ex situ) over a period of 120 days. Growth and survival were evaluated using four substrates viz., tile, block, coral rock and rope) under both in situ and ex situ conditions. L. paradoxa in cages recorded significant increase (p<0.05) on day 90 i.e., by 70% compared to initial volume whereas at 120 days there was a significant (p<0.05) decrease (54.22%). S. massa showed significant increase (p<0.05) in growth by 95.6% at 120 days compared to initial volume. Negative growth was recorded in S. massa under aquarium conditions while L. paradoxa recorded good growth as well as survival and performed exceptionally well in aquarium during the entire experimental period of 120 days. In cages, 90.62% survival was recorded for S. massa in 120 days. Among the different substrates used, coral rocks gave 100% survival whereas other substrates such as tiles, blocks and ropes showed 87.5% survival. Under aquarium conditions, S. massa showed overall survival of 81.25% and among the different substrates, 100% survival was obtained with coral rocks, 87.5% with blocks, 75% with ropes and the lowest survival of 62.5% was recorded with tiles.