Naresh Sahebrao Nagpure

Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch)

The present study was undertaken to evaluate the toxicity and effects of a commercial formulation of the herbicide atrazine (Rasayanzine) on lipid peroxidation and antioxidant enzyme system in the freshwater air breathing fish Channa punctatus. The 12, 24, 48, 72 and 96 h LC50 of atrazine, calculated by probit analysis, were determined to be 77.091, 64.053, 49.100, 44.412 and 42.381 mg·L−1, respectively, in a semi static system with significant difference (p < 0.05) in LC10–90 values obtained for different times of exposure. In addition to concentration and time dependent decrease in mortality rate, stress signs in the form of behavioral changes were also observed in response to the test chemical. In fish exposed for 15 days to different sublethal concentrations of the herbicide (1/4 LC50 = ∼10.600 mg·L−1, 1/8 LC50 = ∼5.300 mg·L−1 and 1/10 LC50 = ∼4.238 mg·L−1) induction of oxidative stress in the liver was evidence by increased lipid peroxidation levels. The antioxidants superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) responded positively in a concentration dependent pattern, thus, suggesting the use of these antioxidants as potential biomarkers of toxicity associated with contaminations exposure in freshwater fishes.

MUTAGENIC AND GENOTOXIC EFFECTS OF CARBOSULFAN IN FRESHWATER FISH CHANNA PUNCTATUS (BLOCH) USING MICRONUCLEUS ASSAY AND ALKALINE SINGLE-CELL GEL ELECTROPHORESIS

Carbosulfan insecticide is widely used in agriculture and was recently proposed for treatment against pyrethroid-resistant mosquitoes. The mutagenic and genotoxic effect of carbosulfan was carried out in fish Channa punctatus using micronucleus (MN) test and comet assay. The 96h LC(50), estimated by probit analysis in a semi-static bioassay experiment, was 0.268 mg l(-1). Based on the LC(50) value, three sub-lethal concentrations of carbosulfan (1/4th LC(50)= approximately 67 microg l(-1), 1/2nd LC(50)= approximately 134 microg l(-1) and 3/4th LC(50)= approximately 201 microg l(-1)) were selected and fishes were exposed to the said concentrations for 96h and the samplings were done at regular intervals of 24h for assessment of the MN frequencies and DNA damage. In general, significant effects (P<0.01) from both concentrations and time of exposure were observed in exposed fishes. The MN induction was highest on 96h at all the concentrations in the peripheral blood. Similar trend was observed for the DNA damage measured in terms of the percentage of tail DNA in the erythrocyte and gill cells. This study confirmed that the comet and micronucleus assays are useful tools in determining potential genotoxicity of water pollutants and might be appropriate as a part of monitoring program.

Profenofos induced DNA damage in freshwater fish, Channa punctatus (Bloch) using alkaline single cell gel electrophoresis

The aim of the present study was to evaluate the induced genotoxicity (DNA damage) due to organophosphate pesticide profenofos (PFF) in gill cells of freshwater fish Channa punctatus using single cell gel electrophoresis (SCGE)/Comet assay. The 96h LC(50) value of PFF (50% EC) was estimated for the fish species in a semistatic system and then three sub-lethal of LC(50) concentrations viz the sub-lethal 1, sub-lethal 2 and sub-lethal 3 concentrations were determined as 0.58ppb, 1.16ppb and 1.74ppb, respectively. The fish specimens were exposed to these concentrations of the pesticide and the gill tissue samplings were done on 24h, 48h, 72h and 96h post exposure for assessment of DNA damage in terms of percentage of DNA in comet tails. In general, a concentration dependent response was observed in the gill cells with induction of maximum DNA damage at the highest concentration of PFF. The results of the present investigation indicated that PFF could potentially induce genotoxic effect in fish, even in sub-lethal concentrations and SCGE as a sensitive and reliable tool for in vivo assessment of DNA damage caused by the genotoxic agents.

DNA damage and oxidative stress modulatory effects of glyphosate-based herbicide in freshwater fish, Channa punctatus.

The present study was undertaken to evaluate the genotoxic and oxidative stress modulatory effects of commercial formulation of glyphosate-based herbicide (Roundup(®)) in freshwater fish Channa punctatus. Three sublethal test concentrations of the herbicide viz., SL-I (1/10th of LC50=∼3.25mgL(-1)), SL-II (1/8th of LC50=∼4.07mgL(-1)) and SL-III (1/5th of LC50=∼6.51mgL(-1)) were calculated using 96-LC50 value and the test specimens were exposed to these concentrations. Blood and gill cells of the exposed specimens were sampled on day 1, 7, 14, 21, 28 and 35 to examine the DNA damage using comet assay and to assess the alteration in lipid peroxidation and antioxidant enzymes activities. The highest DNA damage was observed on day 14 at all test concentrations followed by gradual non-linear decline. Induction of oxidative stress in the blood and gill cells were evidenced by increased lipid peroxidation level, while antioxidants namely superoxide dismutase, catalase and glutathione reductase responded in a concentration-dependent manner. The results supported the integrated use of comet and antioxidant assays in determining the toxicity of water pollutants which could be used as part of monitoring programs.

Genotoxicity and antioxidant enzyme activity induced by hexavalent chromium in Cyprinus carpio after in vivo exposure.

Abstract Fish, being an important native of the aquatic ecosystem, are exposed to multipollution states and are therefore considered as model organisms for ecotoxicological studies of aquatic pollutants, including metal toxicity. We investigated oxidative stress (OS) in liver, kidney and gill tissues through antioxidant enzyme activities and genotoxicity induced in whole blood and gill tissues through comet assay and micronucleus (MN) test in Cyprinus carpio after 96-hour in vivo static exposure to potassium dichromate at three sublethal (SL) test concentrations, including SL-I [93.95 mg/L, i.e. one quarter of half-maximal lethal concentration (LC50)], SL-II (187.9 mg/L, i.e. one half of LC50), and SL-III (281.85 mg/L, i.e. three quarters of LC50), along with a control. The 96-hour LC50 value for potassium dichromate was estimated to be 375.8 mg/L in a static system in the test species. Tissues samples were collected at 24, 48, 72 and 96 hours postexposure. Results indicated that the exposed fish experienced OS as characterized by significant (p < 0.05) variation in antioxidant enzyme activities, as compared to the control. Activities of superoxide dismutase and glutathione peroxidase increased, whereas activity of catalase decreased with the progression of the experiment. The mean percent DNA damage in comet tail and MN induction in gills and whole blood showed a concentration-dependent increase up to 96-hour exposure. The findings of this study would be helpful in organ-specific risk assessment of Cr(VI)-induced OS and genotoxicity in fishes.

Genotoxic and Mutagenic Assessment of Hexavalent Chromium in Fish Following In Vivo Chronic Exposure

ABSTRACT Chromium is a well-documented carcinogen. To evaluate the genotoxic potential of hexavalent chromium on an aquatic bio-system, freshwater murrel fish (Channa punctatus) were exposed to potassium dichromate. The 96-h LC50 for potassium dichromate was 61.80 mg/L for the test fish in a static system. On the basis of the 96-h LC50, fish were exposed to sublethal concentrations of the test chemical. Fish exposed to the test chemical were sampled on days 1, 7, 14, 21, and 28 post-exposure and blood and gill cells were collected. Significantly (p < .05) higher DNA damage in both lymphocyte and gillcells and micronuclei formation in whole blood was observed at different test concentrations and sampling times of the test chemical as compared to control fish. The mean% tail DNA in the comet tail assay showed a concentration-dependent increase and the maximum% tail DNA was observed on day 7 of exposure in both cells. A similar trend was also observed in micronuclei induction in blood with maximum induction on day 21. Hexavalent chromium showed genotoxic potential in chronic exposure of C. punctatus, and the micronucleus test and the comet assay are the methods for sensitive and rapid detection of the genetic effects.

FishMicrosat: a microsatellite database of commercially important fishes and shellfishes of the Indian subcontinent.

BackgroundMicrosatellite DNA is one of many powerful genetic markers used for the construction of genetic linkage maps and the study of population genetics. The biological databases in public domain hold vast numbers of microsatellite sequences for many organisms including fishes. The microsatellite data available in these data sources were extracted and managed into a database that facilitates sequences analysis and browsing relevant information. The system also helps to design primer sequences for flanking regions of repeat loci for PCR identification of polymorphism within populations.DescriptionFishMicrosat is a database of microsatellite sequences of fishes and shellfishes that includes important aquaculture species such as Lates calcarifer, Ctenopharyngodon idella, Hypophthalmichthys molitrix, Penaeus monodon, Labeo rohita, Oreochromis niloticus, Fenneropenaeus indicus and Macrobrachium rosenbergii. The database contains 4398 microsatellite sequences of 41 species belonging to 15 families from the Indian subcontinent. GenBank of NCBI was used as a prime data source for developing the database. The database presents information about simple and compound microsatellites, their clusters and locus orientation within sequences. The database has been integrated with different tools in a web interface such as primer designing, locus finding, mapping repeats, detecting similarities among sequences across species, and searching using motifs and keywords. In addition, the database has the ability to browse information on the top 10 families and the top 10 species, through record overview.ConclusionsFishMicrosat database is a useful resource for fish and shellfish microsatellite analyses and locus identification across species, which has important applications in population genetics, evolutionary studies and genetic relatedness among species. The database can be expanded further to include the microsatellite data of fishes and shellfishes from other regions and available information on genome sequencing project of species of aquaculture importance.

Interaction between shrimp and white spot syndrome virus through PmRab7-VP28 complex: an insight using simulation and docking studies

White spot disease is a devastating disease of shrimp Penaeus monodon in which the shrimp receptor protein PmRab7 interacts with viral envelop protein VP28 to form PmRab7–VP28 complex, which causes initiation of the disease. The molecular mechanism implicated in the disease, the dynamic behavior of proteins as well as interaction between both the biological counterparts that crafts a micro-environment feasible for entry of virus into the shrimp is still unknown. In the present study, we applied molecular modeling (MM), molecular dynamics (MD) and docking to compute surface mapping of infective amino acid residues between interacting proteins. Our result showed that α-helix of PmRab7 (encompassing Ser74, Ile143, Thr184, Arg53, Asn144, Thr184, Arg53, Arg79) interacts with β-sheets of VP28 (containing Ser74, Ile143, Thr184, Arg53, Asn144, Thr184, Arg53, Arg79) and Arg69-Ser74, Val75-Ile143, Leu73-Ile143, Arg79-Asn144, Ala198-Ala182 bonds contributed in the formation of PmRab7–VP28 complex. Further studies on the amino acid residues and bonds may open new possibilities for preventing PmRab7–VP28 complex formation, thus reducing chances of WSD. The quantitative predictions provide a scope for experimental testing in future as well as endow with a straightforward evidence to comprehend cellular mechanisms underlying the disease.

In situ assessment of genotoxic and mutagenic potential of polluted river water in Channa punctatus and Mystus vittatus

River Gomti, a tributary of river Ganga in northern India, is being polluted due to indiscriminate disposal of domestic sewage and industrial wastes that contain genotoxic chemicals. The study was conducted to evaluate the genotoxic potential of polluted water of river Gomti in two fish species, namely Channa punctatus and Mystus vittatus. The fishes were exposed in situ in nylon cages to the polluted water of river Gomti fixed near a distillery outlet located in Lucknow. The induction of DNA damage and micronuclei were determined in blood erythrocytes using comet assay and micronucleus test, respectively. The induction in micronuclei frequencies and DNA damage were found to be significantly elevated (p < 0.01) in exposed specimens after 3 days post-exposure as compared to the control, i.e. from laboratory-acclimatized fish specimens. The comparison of DNA damage between the two species indicated that C. punctatus is more sensitive to aquatic pollutants. Thus, this fish could be used as a bio-indicator of genotoxicity for bio-monitoring of water bodies. The results further revealed that the river Gomti is being contaminated with potential genotoxic and mutagenic chemicals produced from industrial and domestic activities; therefore, immediate measures are needed to reduce the inflow of pollutants in the river.

FBIS: A regional DNA barcode archival & analysis system for Indian fishes.

DNA barcode is a new tool for taxon recognition and classification of biological organisms based on sequence of a fragment of mitochondrial gene, cytochrome c oxidase I (COI). In view of the growing importance of the fish DNA barcoding for species identification, molecular taxonomy and fish diversity conservation, we developed a Fish Barcode Information System (FBIS) for Indian fishes, which will serve as a regional DNA barcode archival and analysis system. The database presently contains 2334 sequence records of COI gene for 472 aquatic species belonging to 39 orders and 136 families, collected from available published data sources. Additionally, it contains information on phenotype, distribution and IUCN Red List status of fishes. The web version of FBIS was designed using MySQL, Perl and PHP under Linux operating platform to (a) store and manage the acquisition (b) analyze and explore DNA barcode records (c) identify species and estimate genetic divergence. FBIS has also been integrated with appropriate tools for retrieving and viewing information about the database statistics and taxonomy. It is expected that FBIS would be useful as a potent information system in fish molecular taxonomy, phylogeny and genomics. Availability The database is available for free at http://mail.nbfgr.res.in/fbis/