Subhasish Bandyopadhyay

Effect of chronic intake of arsenic-contaminated water on blood oxidative stress indices in cattle in an arsenic-affected zone.

This study aimed to determine the hemato-biochemical picture and blood oxidative stress in zebu cattle in an arsenic-contaminated zone. Significant decline in total erythrocyte count, packed cell volume, and total plasma protein was observed in cattle of that area in comparison to uncontaminated zone. There was significant elevation of plasma enzyme activities of both alanine aminotransaminase and aspertate aminotransaminase. Increased corpuscular osmotic fragility also proved to be a mechanism for deviation from normal functioning of erythrocytes. Cattle in the affected zone showed a significantly higher arsenic burden in blood. Those animals further showed decreased superoxide dismutase, catalase activities of erythrocytes, and plasma nitrite level, but increased lipid peroxidation and protein carbonyl level. Our finding concluded that cattle of the arsenic-contaminated zone is suffering from a subclinical form of arsenic toxicity, which is proved through altered hemato-biochemical indices and a certain extent of oxidative stress with higher arsenic concentration in blood.

Effect of ascorbic acid on blood oxidative stress in experimental chronic arsenicosis in rodents.

Ascorbic acid is a sugar acid and an essential vital food nutrient found mainly in fruits and vegetables. The purpose of this study was to investigate the effects of ascorbic acid against arsenic induced oxidative stress in blood of rat. In rat, treatment with ascorbic acid prevented the increased serum enzymatic activity of AST, ALT, ALP, ACP and LDH. In addition, treatment with ascorbic acid prevented elevated production of LPO, PC and NO and restored the depletion of reduced SOD and CAT activities. Interestingly, ascorbic acid markedly upregulated lymphocytes relative mRNA expression of lymphocytes SOD2 gene corresponding to GAPDH, house keeping candidate gene in arsenic-treated rat, which might provide anti-oxidative activity in the blood.

L-Ascorbate protects rat hepatocytes against sodium arsenite—induced cytotoxicity and oxidative damage:

Sodium arsenite—exposed hepatocytes of rat showed higher production of nitric oxide (NO) and increased lipid peroxidation (LPO) level vis-a-vis activity of superoxide dismutase (SOD) and catalase (CAT) were significantly lowered. Subsequently, the cell proliferation index (CPI) and cell viability were also reduced. Treatment with L-ascorbate was found effective in normalizing the arsenic-induced alteration of SOD and CAT activity and LPO level in rat hepatocytes. These observations indicated that L-ascorbate also has potent cytoprotective role as it could reduce the NO production and normalize the cell proliferation and viability of hepatocytes. Therefore, the in vitro study suggested that ascorbic acid is helpful to ameliorate the arsenic-induced cytotoxicity and oxidative stress of rat hepatocytes.

Molecular and phylogenetic characterization of multidrug resistant extended spectrum beta-lactamase producing Escherichia coli isolated from poultry and cattle in Odisha, India.

The present study was undertaken to determine the occurrence and characterization of extended spectrum beta-lactamase (ESBL) producing Escherichia coli isolated from cattle and poultry in Odisha, India. Of 316 E. coli isolated from 305 samples (170 fecal samples from poultry and 135 milk samples from cattle), a total of 18 E. coli isolates were confirmed as ESBL producers by combination disc method and ESBL E-test. The isolates were resistant to oxyimino cephalosporins and monobactam as revealed by disc diffusion assay and determination of minimum inhibitory concentration. Resistance against other antibiotics was frequently noted as well. Further, beta-lactamase genes viz., blaSHV, blaCTXM, blaTEM and blaampC were detected in 17, 13, 9 and 2 isolates, respectively in PCR. Of the 18 ESBL strains, 16 were positive for class I integron (int1), nine of them carried sulphonamide resistance gene (sul1) and one harbored quinolone resistance gene (qnrB). Virulence markers for extraintestinal pathogenic E. coli like astA, tsh and iucD were also present in 4, 3 and 3 isolates, respectively. All the PCR amplified products were cloned and subjected to sequencing for homology analysis and data were submitted to gene bank. Sequence analysis of the amplified variable regions of class 1 integron of four representative isolates revealed the presence of aadA2 and dfrA12 gene cassettes conferring resistance to aminoglycosides and trimethoprim, respectively. Most of the ESBL producing strains emerged as single lineage through phylogenetic analysis by RAPD and ERIC PCR. This is the first ever systemic study on multidrug resistant ESBL producing E. coli in food producing animals from India.

Ground water arsenic contamination in West Bengal, India: a risk of sub-clinical toxicity in cattle as evident by correlation between arsenic exposure, excretion and deposition.

Arsenic contamination of ground water in West Bengal, India, is a great concern for both human and livestock populations. Our study investigated and correlated the arsenic concentration in the drinking water, urinary excretion and deposition of total arsenic in hair of cattle at an arsenic contaminated zone in West Bengal. The results of our study indicated that the average concentration of arsenic in tube well water in contaminated villages ranged from 0.042 to 0.251 ppm and a statistical significant (p < 0.01) difference was seen when compared to samples from a non-contaminated zone. The arsenic concentration in urine and hair of cattle ranged between 0.245—0.691 ppm and 0.461—0.984 ppm, respectively. A close relationship was found between the total arsenic in drinking water urinary excretion (r2 = 0.03664, p < 0.05) and the arsenic concentration in hair (r2 = 0.03668, p < 0.05). Our findings indicate that quantification of arsenic concentration in cattle urine and hair can serve as biomarkers for both present and past exposure in cattle population.

Pleurotus florida lectin normalizes duration dependent hepatic oxidative stress responses caused by arsenic in rat

Natural contamination of arsenic in ground water is a major health problem throughout the World. It is one of the most hazardous substances in the environment known to cause toxicity in multiple organs via oxidative stress. The molecular basis for arsenic toxicity involves direct or indirect damage to protein, lipid and DNA. Various studies have focused on the possible toxic effects of arsenic on membrane components and its correlation with oxidative damage. The present study was aimed to mitigation of arsenic induced hepatic oxidative stress by dietary modulation using of mushroom lectin in rats. Animals were divided into four groups; the first group was used as control. Groups 2, 3 and 4 were arsenic (20 ppm) exposed through drinking water, arsenic exposed plus oral ascorbic acid (25 mg/kg body weight) and arsenic exposed plus oral mushroom lectin (150 mg/kg body weight) respectively for a period of 12 weeks. We observed significant alterations in the antioxidant enzymes, oxidative stress intermediates and SOD(2) gene expression profile on arsenic exposure. These alterations were restored by co-administration of Pleurotus florida lectin which was as potent as standard antioxidant viz. ascorbic acid. The findings of the experiment suggested that P. florida lectin has capability of modulating arsenic mediated toxic effects and could be helpful in ameliorating them.

Supplementation of ascorbic acid prevents oxidative damages in arsenic-loaded hepatic tissue of rat: An ex vivo study

Oxidative stress due to arsenic toxicity and ameliorative potentiality of L-ascorbic acid was evaluated in an ex vivo system of rat hepatic tissue. The study revealed that arsenic increased the activity of superoxide dismutase (SOD) and catalase (CAT) and the level of lipid peroxidation (LPO), protein carbonyl (PC) and nitric oxide (NO) at 1 hour, 1.5 hours and 2 hours of incubation. Co-treatment with L-ascorbic acid was found effective to normalize the activity of SOD and CAT and the production of LPO, PC and NO in hepatic tissue. This ex vivo study suggested that ascorbic acid is helpful to ameliorate arsenic-induced oxidative stress. This may be one of the alternative screening systems to study the efficacy of antioxidant and hepatoprotective agent.

Mitigation of arsenic-mediated renal oxidative stress in rat by Pleurotus florida lectin

Oyster mushroom, Pleurotus florida is regarded as one of the popular food with biopharmaceutical properties. Here, the study aimed to investigate the antioxidative effects of mushroom (Pleurotus florida) lectin against arsenic-induced nephrotoxicity in rats. Animals were divided into four groups; Group 1 was control. Groups 2, 3 and 4 were exposed to arsenic (20 parts per million [ppm] in drinking water), arsenic plus oral supplementation of ascorbic acid (25 mg/kg body weight) and arsenic plus oral supplementation of mushroom lectin (150 mg/kg body weight) respectively. Both ascorbic acid and mushroom lectin prevented the arsenic-mediated growth retardation and normalized the elevated kidney weight. Disrupted activities of superoxide dismutase (SOD) and catalase (CAT) and enhanced lipid peroxidation (LPO), protein carbonyl (PC) and nitric oxides (NO) production in kidney caused by arsenic could also be maintained towards normalcy by supplementation of mushroom lectin and ascorbic acid. These antioxidative effects were exhibited in a time-dependant manner. Further, arsenic-mediated down-regulation of messenger RNA (mRNA) expression of superoxide dismutase 2 (SOD2) gene was obstructed by these agents. Thus it was found that mushroom lectin reversed the effect of arsenic-mediated oxidative stress in a time-dependent manner.

Co-infection of methicillin-resistant Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus and extended spectrum β-lactamase producing Escherichia coli in bovine mastitis – three cases reported from India

Emergence of antimicrobial resistance among bovine mastitis pathogens is the major cause of frequent therapeutic failure and a cause of concern for veterinary practitioners. This study describes intra-mammary infection of methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) producing Escherichia coli in two Holstein Friesian crossbred cows with subclinical mastitis and one non-descript cow with clinical mastitis in two different districts of West Bengal, India. In total, three MRSE, one MRSA and three ESBL producing E. coli were isolated from these cases. Both the crossbreds were detected with MRSE (HFSE1 and HFSE2) and ESBL producing E. coli (HFEC1 and HFEC2), whereas, simultaneous infection of three pathogens viz. MRSA (NDSA1), MRSE (NDSE1) and ESBL producing E. coli (NDEC1) was found in the non-descript cow. The methicillin-resistant isolates possessed mecA gene and exhibited resistance to various antibiotics such as amikacin, tetracycline and glycopeptides. The ESBL producers were positive for blaCTX-M and blaTEM genes; in addition, HFEC1 and HFEC2 were positive for blaSHV and possessed the genes for class I integron (int1), sulphonamide resistance (sul1), quinolone resistance (qnrS) and other virulence factors (papC, iucD and ESTA1). All the ESBL producers exhibited resistance to a variety of antibiotics tested including third- and fourth-generation cephalosporins and were also intermediately resistant to carbapenems. This is the first ever report on simultaneous occurrence of MRSE, MRSA and ESBL producing E. coli in bovine mastitis indicating a major concern for dairy industry and public health as well.

Molecular basis for identification of species/isolates of gastrointestinal nematode parasites

Gastrointestinal (GI) parasitism is the most serious constraint throughout the world in small ruminants which causes significant production loss in animals. GI parasites are major contributor to reduce productivity in terms of meat, milk and wool in animals. Control of GI parasite is done primarily by anthelmintic treatment where choice and schedule of treatment is done after identification and quantitation of individual parasite. Identification of GI parasites is done through microscopic method by identifying specific morphological characteristics of egg and larva (L(3)). Since most of parasite eggs are having similar morphological characteristics, identification up to species level through microscopy is not possible in most of cases. To address this issue, molecular techniques are the viable alternative for identification of species as well as molecular level differences within a species (isolates) of parasites. Different DNA based molecular techniques viz. PCR, AFLP, RAPD, RFLP, PCR-SSCP, real time PCR, DNA microarray etc. have been used for identification and to assess the genetic diversity among parasite population. For identification of species, the characteristic sequence of genomic DNA of different species should differ to allow the delineation of species, but at the same time, no/minor variation within the species should exist. In contrast, for purpose of identifying population variants (strains/isolates), a considerable degree of variation in the sequence should exist within a species. Various target regions, including nuclear ribosomal DNA (rDNA), mitochondrial DNA (mtDNA) or repetitive DNA elements (microsatellite loci), which show considerable variation in the number of repeats within individuals have been employed to achieve the identification of parasites species or strain.