Research Interests:
An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of the Indian white shrimp, Fenneropenaeus indicus by investigating the time-course expression of female reproduction gene, namely vitellogenin... more
An experiment was conducted to explore the pathogenic effect of WSSV infection in reproduction of the Indian white shrimp, Fenneropenaeus indicus by investigating the time-course expression of female reproduction gene, namely vitellogenin (Vg) and thrombospondin (TSP), following WSSV challenge. Increased levels of expression for both Vg and TSP was observed in the infected group at 30 h post-infection followed by a decrease in the levels at 60 h post infection compared to the controls. The results indicate that both Vg and TSP might play a role in the immune functions of shrimp in addition to their well known roles in reproduction in penaeid shrimps.
Research Interests:
The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio... more
The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system wit...
Research Interests:
Research Interests:
Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nitrogen concentration, act as in situ food source and eradicate pollutants using carbon and therefore to control C:N ratio in an aquaculture... more
Biofloc technology (BFT) is a novel modern aquaculture farming technique used to reduce toxic nitrogen concentration, act as in situ food source and eradicate pollutants using carbon and therefore to control C:N ratio in an aquaculture system. In this study, effect of different C:N ratios of a biofloc based system on water quality such as the level of Total ammonia nitrogen (TAN) nitrite-nitrogen (NO-N) and nitrate nitrogen (NO-N) were explored. Further, the growth and immunity status of shrimp L. vannamei under the influence of different C:N ratios were evaluated. Two of the C:N ratios (15 and 20) could significantly (P < 0.05) reduce TAN, NO-N and NO-N levels (0.456 ± 0.01, 0.145 ± 0.09, and 0.102 ± 0.02 ppm) compared to control (1.45 ± 0.1, 0.749 ± 0.14 and 0.675 ± 0.16 ppm). Large variations in the frequency distribution of operational taxonomic units (OTUs) for the bacterial community in water with different C:N ration (BFT) and control were observed. Vibrios often considere...
Research Interests:
is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first time, a completegenome of an Indian isolate of this virus has been deciphered using Illumina and Nanopore sequencing technologies. The genome... more
is a major pathogen of shrimp, causing economic loss to the aquaculture industry. For the first time, a completegenome of an Indian isolate of this virus has been deciphered using Illumina and Nanopore sequencing technologies. The genome has 280,591 bp with 442 predicted coding genes.
Research Interests:
The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gills and ulcers in the uropod and telson region. PCR for OIE listed viral pathogens ruled out known viral infections. No bacteria was present... more
The moribund shrimps were exhibiting yellow discoloration of the cephalothorax, blackening of gills and ulcers in the uropod and telson region. PCR for OIE listed viral pathogens ruled out known viral infections. No bacteria was present in haemolymph however, low level of Vibrios i.e. Vibrio harveyi, V. parahaemolyticus and V. alginolyticus was found both in the water collected from the broodstock tanks and affected tissue region. Histopathological examination of affected tissues revealed presence of highly invasive fungal hyphae both by routine and specific fungal stain. PCR amplification of the ITS region (approximately 900 bp) and sequencing confirmed presence of Pythium insidiosum . Phylogenetic analysis of this isolate placed it among the environmental isolates.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain of it harbouring toxic plasmid can cause Acute Hepatopanreatic Necrosis Disease (AHPND) to shrimp. An attempt was made to isolate and... more
Abstract Vibrio parahaemolyticus is an important shrimp & human pathogen and a special strain of it harbouring toxic plasmid can cause Acute Hepatopanreatic Necrosis Disease (AHPND) to shrimp. An attempt was made to isolate and further characterize this bacterium from shrimp farms of south east coast of India. From 381 shrimp farms sampled over a period of four years, 105 isolates were presumptively identified as V. parahaemolyticus. All the 105 isolates were found to be negative for PirA and PirB toxin, characteristic of AHPND V.parahaemolytiucs. The challenge experiments with representative isolates required higher number of bacteria to cause shrimp mortality. The isolates were negative for thermostable direct haemolysin (tdh), tdh related haemolysin (trh) and type III secretion system alpha and beta. The isolates were tested to be sensitive to majority of the antibiotics. This study thus indicates that V. parahaemolyticus isolates recovered from aquaculture ponds of Southeast coast of India are non-shrimp pathogenic and non-human pathogenic. Direct tissue samples (hepatopancreas and stomach) and Tryptic Soy Broth enriched bacteria population from these tissues were also found to be negative for PirA and PirB toxin, characteristic of AHPND. Based on this evidence, AHPND was not detected in any of the samples collected from these shrimp culturing areas.
Research Interests:
Research Interests:
Motile aeromonads are a heterogeneous group of organisms which are involved in a number of disease syndromes of warm water fish. They are commonly associated with bacterial haemorrhagic septicaemia, infectious dropsy, red mouth disease,... more
Motile aeromonads are a heterogeneous group of organisms which are involved in a number of disease syndromes of warm water fish. They are commonly associated with bacterial haemorrhagic septicaemia, infectious dropsy, red mouth disease, ulcerative conditions etc. A variety of factors has been considered to be associated with virulence including haemolysins, proteases, surface array protein, acetylcholinesterase etc. We have studied the immune response of Indian major carps to antigens of motile aeromonads. The Indian major carp, Labeo rohita, showed immunological memory and secondary response on booster administration. The extent of protection showed good correlation with titres of agglutinating antibody. When polyvalent vaccine was used, the fish showed antibody titres against all the component strains. However, the level of antibody was less compared to immunization by monovalent vaccines. Cross-reacting antibodies induced by monovalent vaccines showed varying degrees of protection.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
A study was undertaken to investigate the cause of mortality in the captive stock of Indian halibut, Psettodes erumei (Bloch & Schneider, 1801) (Psettodidae) at Kovalam Field Laboratory, Research Centre of Central Marine Fisheries... more
A study was undertaken to investigate the cause of mortality in the captive stock of Indian halibut, Psettodes erumei (Bloch & Schneider, 1801) (Psettodidae) at Kovalam Field Laboratory, Research Centre of Central Marine Fisheries Research Institute (CMFRI), Chennai, India. The halibuts were severely infected with two species of parasitic copepods, Protochondracanthus alatus (Heller, 1868) and P. trilobatus (Pillai, 1964) (Poecilostomatoida, Chondracanthidae) and also with protozoan Amyloodinium sp. (Blastodinida, Oodiniaceae) on gills. Since the parasitic copepods have high host specificity on P. erumei, a large number of copepods were collected. The gill lamellae appeared pale and excess mucous secretion was observed on the body surface. Histopathological changes were mainly in the gill tissues with severe lamellar hypertrophy and hyperplasia, lamellar fusions with the presence of trophonts of Amyloodinium sp. Wild caught tilapia, and juveniles of mullet and milkfish used as live ...
Research Interests: Oceanography, Biology, Treatment, Mortality, Fish Disease, and 3 moreCopepods, Gill, and Psettodes erumei
Aquaculture is one of the fastest growing sectors yielding more than 10% growth rate per annum over the past 10 years, with a contribution of about 16% of animal protein production globally. Aquaculture production has surpassed that of... more
Aquaculture is one of the fastest growing sectors yielding more than 10% growth rate per annum over the past 10 years, with a contribution of about 16% of animal protein production globally. Aquaculture production has surpassed that of the other meat producing sectors. Diseases, especially of viral etiology, remains a stumbling block for the growth of this sector posing great threat. The major viruses affecting shrimps in India are white spot syndrome virus (WSSV) and infectious hypodermal hematopoietic necrosis virus (IHHNV). Besides this, monodon baculovirus (MBV) and hepatopancreatic parvovirus (HPV) also cause considerable loss to the shrimp farmers. MBV outbreaks can cause mass mortalities when combined with other viral diseases. Moreover, MBV and HPV infections can lead to slow growth in cultured penaeid shrimps, thereby affecting the production. Although studies pertaining to the prevalence of these two viruses in the tiger shrimp Penaeus monodon have been reported extensivel...
Research Interests:
The present paper documents the molecular diagnosis and genotyping of white spot syndrome virus (WSSV) isolates collected from different shrimp farms of Gujarat, north-west coast of India. Preliminary diagnosis was done using singletube... more
The present paper documents the molecular diagnosis and genotyping of white spot syndrome virus (WSSV) isolates collected from different shrimp farms of Gujarat, north-west coast of India. Preliminary diagnosis was done using singletube PCR and genotyping of isolates by analysis of variable number tandem repeat sequence (VNTRS) in minisatellites viz., ORF 94, ORF 125, ORF 75 and ORF 75 flank. Out of the 79 samples analysed, 32 (33.80%) were positive with low (54.17%), medium (8.33%) and high (37.50%) severity of infection. Genotyping, using ORF 94 revealed that repeat units (RUs) 4 and 11 were the most frequent ones (32%) while ORF 125 showed 5 different repeat types of which RU 5 was the most common (45.83%). Two genotypes were observed for ORF 75, one showed multiple repeats of two 45 bp, followed by a 57 bp, whereas the other showed two repeats that included 5 and 4 repeats of 45 bp. Sequence analysis of the 54 bp variable sequence of ORF 94 RU type 4 revealed single-nucleotide p...
Research Interests:
Research Interests:
... Saeed Sepehriseresht &amp;amp; Taghi Zahraei Salehi &amp;amp; Morteza Sattari &amp;amp; Hasan Tadjbakhsh &amp;amp; Mohammad Mehdi Aslani ... of Tehran for financial support and project No.7504002/6/4 and also, we are... more
... Saeed Sepehriseresht &amp;amp; Taghi Zahraei Salehi &amp;amp; Morteza Sattari &amp;amp; Hasan Tadjbakhsh &amp;amp; Mohammad Mehdi Aslani ... of Tehran for financial support and project No.7504002/6/4 and also, we are thankful to Professor Nadalian, MG, Dr. Lotfollahzadeh, S., and Dr. Askari M. for their ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Present investigation provides information on the availability of Black-margined nudibranch which were caught by trawl gears operated along the Karaikal coast of south India at a depth of around 150-200 m during 16 October 2012. Specimens... more
Present investigation provides information on the availability of Black-margined nudibranch which were caught by trawl gears operated along the Karaikal coast of south India at a depth of around 150-200 m during 16 October 2012. Specimens were identified as Doriprismatica atromarginata. This species has not been reported earlier and therefore considered as a new record to the inshore waters of Bay of Bengal along Karaikal coast.
I (1998) Immunostimulation of shrimp through oral administration of Vibrio bacterin and yeast glucan. In Flegel TW (ed) Advances in shrimp biotech-nology. National Center for Genetic Engineering and Biotechnology, Bangkok. ABSTRACT: The... more
I (1998) Immunostimulation of shrimp through oral administration of Vibrio bacterin and yeast glucan. In Flegel TW (ed) Advances in shrimp biotech-nology. National Center for Genetic Engineering and Biotechnology, Bangkok. ABSTRACT: The effect of oral administration of Vibrio bacterin and yeast glucan to black tiger shrimp, Penaeus monodon was studied. Vibriocidal activity was detectable in hemolymph and hemocyte lysate. The activity peaked at 48 h post treatment but persisted even at 72 h. Generation of reactive oxygen species in hemocytes could be detected by nitroblue tetrazolium (NBT) assay. Enhanced phenol oxidase activity was observed in hemocytes of treated shrimp. When a combination of bacterin and glucan was administered, the response was much higher compared to individual treatments. The results suggest that immunostimulation of shrimp can be achieved through oral administration of a combination of Vibrio bacterin and yeast glucan.
The tissue-specific expression and differential function of the crustacean hyperglycemic hormone (CHH) in Carcinus maenas indicate an interesting evolutionary history. Previous studies have shown that CHH from the sinus gland X-organ... more
The tissue-specific expression and differential function of the crustacean hyperglycemic hormone (CHH) in Carcinus maenas indicate an interesting evolutionary history. Previous studies have shown that CHH from the sinus gland X-organ (XO-type) has hyperglycemic activity, whereas the CHH from the pericardial organ (PO-type) neither shows hyperglycemic activity nor it inhibits Y-organ ecdysteroid synthesis. Here we examined the types of selective pressures operating on the variants of CHH in Carcinus maenas. Maximum likelihood-based codon substitution analyses revealed that the variants of this neuropeptide in C. maenas have been subjected to positive Darwinian selection indicating adaptive evolution and functional divergence among the CHH variants leading to two unique groups (PO and XO-type). Although the average ratio of nonsynonymous to synonymous substitution (omega) for the entire coding region is 0.5096, few codon sites showed significantly higher omega (10.95). Comparison of m...
Research Interests:
Listeria monocytogenes is an important food-borne pathogen causing meningitis and septicaemia in newborns and immunocompromised persons, abortion and preterm labour in pregnant women. Though various methods are available for typing L.... more
Listeria monocytogenes is an important food-borne pathogen causing meningitis and septicaemia in newborns and immunocompromised persons, abortion and preterm labour in pregnant women. Though various methods are available for typing L. monocytogenes, RAPD analysis has been used for epidemiological purposes in developed countries due to its greater discriminating ability. However, as there are no published reports from India on the typing of L. monocytogenes by RAPD technique the present study was undertaken to type isolates of L. monocytogenes from clinical, food and veterinary samples. Isolates of L. monocytogenes were subjected to RAPD using four decamer random primers R1, R2, R3 and R4. Amplified products were analysed by agarose gel electrophoresis. Eight strains of L. monocytogenes on RAPD analysis generated 4 distinct profiles each with R1 and R4 primers and 3 different profiles with R2 and R3 primers. The isolates from fish, clinical and veterinary samples showed different pro...
Research Interests:
Research Interests:
Protein-protein interaction studies have been widely used in several fields to characterize an unknown protein. This in turn helps to find out several pathways to understand a complex mechanism or discover a drug for treatment. Among the... more
Protein-protein interaction studies have been widely used in several fields to characterize an unknown protein. This in turn helps to find out several pathways to understand a complex mechanism or discover a drug for treatment. Among the methods, yeast two-hybrid has widely been used in human, animal and plant research studies. This aspect of research has also been found useful in understanding the shrimp virus gene function. With respect to White spot syndrome virus, interaction studies have been applied to elucidate virus structure, understand the mode of entry of the virus, mechanism of virus replication and also to discover some of the host anti-viral proteins. Interaction studies on other shrimp viruses are scanty and only few reports available on Yellow head virus and Taura syndrome virus. All these findings are still in preliminary stage and lot more studies are necessary to have the clear picture. Protein interaction research on other shrimp viruses are still lacking. Considering all these, it appears that this field of research has a wide scope to understand the virulence mechanism of shrimp viruses where very little information is available till date.
In this study, dsRNA specific to VP28 gene of white spot syndrome virus (WSSV) of shrimp was synthesized in Escherichia coli in large scale and studied the immune response of shrimp to dsRNA-VP28. The haematological parameters such as... more
In this study, dsRNA specific to VP28 gene of white spot syndrome virus (WSSV) of shrimp was synthesized in Escherichia coli in large scale and studied the immune response of shrimp to dsRNA-VP28. The haematological parameters such as clotting time and total haemocytes counts, and immunological parameters such as prophenoloxidase (proPO), superoxide dismutase (SOD), superoxide anion (SOA) and malondialdehyde content, as well as the mRNA expression of ten immune-related genes were examined to estimate the effect of dsRNA-VP28 on the innate immunity of Litopenaeus vannamei. The activities of proPO, SOA and SOD significantly increased in haemocyte after dsRNA-VP28 treatment, whereas MDA content did not change significantly. Among the ten immune-related genes examined, only the mRNA expression of proPO, cMnSOD, haemocyanin, crustin, BGBP, lipopolysaccharides (LPs), lectin and lysozyme in haemocytes, gill and hepatopancreas of L. vannamei, was significantly upregulated at 12 h after dsRNA-VP28 treatment, while no significant expression changes were observed in Toll receptor and tumour receptor genes. The increase of proPO and SOD activities, and SOA level and mRNA expression level of proPO, cMnSOD, haemocyanin, crustin, BGBP, LPs, lectin and lysozyme after dsRNA-VP28 stimulation indicate that these immune-related genes were involved in dsRNA-VP28-induced innate immunity in shrimp.
Research Interests:
Research Interests:
... 1995. Viral nervous necrosis in brown spotted grouper, Epinephelus malabaricus, cultured in Thailand. Pages 227-233 in M. Shariff, JR Arthur, and RP Subasinghe ed. Diseases in Asian Aquaculture II. Asian Fisheries Society, Manila, The... more
... 1995. Viral nervous necrosis in brown spotted grouper, Epinephelus malabaricus, cultured in Thailand. Pages 227-233 in M. Shariff, JR Arthur, and RP Subasinghe ed. Diseases in Asian Aquaculture II. Asian Fisheries Society, Manila, The Philippines. ...