Arabinda Mahanty

Amino Acid Compositions of 27 Food Fishes and Their Importance in Clinical Nutrition

Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs.

Investigating hsp Gene Expression in Liver of Channa striatus under Heat Stress for Understanding the Upper Thermal Acclimation

Changes in hsp gene expression profiles in murrel Channa striatus experimentally exposed to temperature stress (36°C) for 4, 15, and 30 days were investigated; fish collected from aquaculture ponds and maintained in laboratory at the pond temperature (25 ± 1°C) served as control. Channa collected from a hot spring runoff (36°C) was included in the study to examine the hsp profiles beyond 30 days of exposure. Gene expression analyses of a battery of hsps in liver tissues were carried out by quantitative RT-PCR and protein expressions were analyzed by immunoblotting. hsps could be grouped into three clusters based on similarity in response to heat stress: hsp70, hsp78, and hsp60, whose transcript level continued to increase with duration of exposure; hsp90 and hsp110 that increased to a much higher level and then decreased; hsp27 and hsp47 that did not significantly vary as compared to control. The results suggest that Hsp70, Hsp78, and Hsp60 are involved in thermal acclimation and long term survival at high temperature. Fish living in the hot spring runoff appears to continuously express hsps that can be approximated by long term induction of hsps in farmed fish if temperature of their environment is raised to 36°C.

DHA and EPA Content and Fatty Acid Profile of 39 Food Fishes from India

Docosahexaenoic acid (DHA) is the principal constituent of a variety of cells especially the brain neurons and retinal cells and plays important role in fetal brain development, development of motor skills, and visual acuity in infants, lipid metabolism, and cognitive support and along with eicosapentaenoic acid (EPA) it plays important role in preventing atherosclerosis, dementia, rheumatoid arthritis, Alzheimers disease, and so forth. Being an essential nutrient, it is to be obtained through diet and therefore searching for affordable sources of these ω-3 polyunsaturated fatty acids (PUFA) is important for consumer guidance and dietary counseling. Fish is an important source of PUFA and has unique advantage that there are many food fish species available and consumers have a wide choice owing to availability and affordability. The Indian subcontinent harbors a rich fish biodiversity which markedly varies in their nutrient composition. Here we report the DHA and EPA content and fatty acid profile of 39 important food fishes (including finfishes, shellfishes, and edible molluscs from both marine water and freshwater) from India. The study showed that fishes Tenualosa ilisha, Sardinella longiceps, Nemipterus japonicus, and Anabas testudineus are rich sources of DHA and EPA. Promotion of these species as DHA rich species would enhance their utility in public health nutrition.

Lipid Biomarkers of Lens Aging

Lipids are important structural components of cell membranes and have profound effect on membrane fluidity. Lipid profiling and lipidomics have captured increased attention due to the well-recognized roles of lipids in numerous human diseases. Investigating lipid profiles not only provides insights into the specific roles of lipid molecular species in health and diseases, but can also help in identifying potential preventive or therapeutic biomarkers. Cataract, the loss of transparency of eye lens, is a disease of protein aggregation. There are several factors contributing to the stability in protein conformation. Age-related changes in lipid composition could be a contributing factor for altered protein–lipid interaction leading to protein aggregation and cataract. Keeping this in view, in the present study, fatty acid profiling from different age groups of lenses was carried out, using a freshwater catfish as the model. Total lipids were extracted from lenses of three different age groups of fishes (young, adult, and aged) and fatty acid methyl esters (FAME) were prepared and FAME analysis was carried out using gas chromatography–mass spectrometry. The results showed that three fatty acids viz. heneicosylic acid (C21), docosahexaenoic acid (C22:6), nervonic acid (C24:1) which were not present in the adult lens, appeared in the aged lens. On the other hand, eicosenoic acid (C20:1) present in the adult lens was found to be absent in the aged lens. The appearance or disappearance of these fatty acids can possibly serve as biomarkers of aging lens which is the most vulnerable stage for cataract development.

Evaluation of housekeeping genes as references for quantitative real-time PCR analysis of gene expression in the murrel Channa striatus under high-temperature stress

Quantitative real-time polymerase chain reaction is the most advanced method of quantifying gene expression studies; however, the significance of the obtained results strongly depends on the normalization of the data to compensate for differences between the samples. In the present study, expression analysis of six different constitutively expressed genes viz. 18S ribosomal RNA, glyceraldehyde-3-phosphate dehydrogenase (gapdh), beta actin (βactin), ribosomal binding protein L13, tubulin and TATA-box-binding protein (tbp) were carried out to test their efficacy as reference genes in three different tissues, namely liver, gill and muscle of murrel Channa striatus exposed to high temperature for variable time periods. The stability and suitability of the genes were determined by using bioinformatic tools: GeNorm, NormFinder and BestKeeper. Based on the results, tub/βactin could be used as the reference genes for liver and gill tissues and βactin/gapdh could be the reference genes for muscle tissues in Channa striatus under both short- and long-term thermal stress.

Proteomic changes in the liver of Channa striatus in response to high temperature stress

The present study was undertaken to investigate the proteomic changes in the liver of murrel Channa striatus exposed to high temperature stress. Fishes were exposed to 36°C for 4 days and liver proteome changes were analyzed using gel‐ based proteomics, i.e. 2DE, MALDI‐TOF/TOF‐MS, and validation by transcript analysis. The study showed, besides others, increased abundance of two sets of proteins, the antioxidative enzymes superoxide dismutase (SOD), ferritin, cellular retinol binding protein (CRBP), glutathione‐S‐transferase (GST), and the chaperones HSP60 and protein disulfide isomerase; this was validated by transcript analysis. The proteome data are available via ProteomeXchange with identifier PXD002608. Further, gene expression analysis was also carried out in the fishes exposed to thermal stress for longer durations (30 days experimental exposure in laboratory and for 30 days beyond, taking Channa collected from a hot spring runoff at 36–38°C); sod, gst, crbp, and hsp60 were found to continue to remain upregulated at eight‐, 2.5‐, 2.4‐, and 2.45‐fold, respectively, in the hot spring runoff fish. Pathway analysis showed that the upregulations of the antioxidant enzymes as well as molecular chaperones are induced by the transcription factor Nrf2 (nuclear factor erythroid 2‐related factor 2). Thus, while short‐term heat stress tolerance involves the antioxidative enzymes SOD, ferritin, CRBP, GST, and chaperones HSP60 and protein disulfide isomerase, adaptation under chronic heat stress is associated with SOD, CRBP, GST, and HSP60.

Micronutrient Composition of 35 Food Fishes from India and Their Significance in Human Nutrition

The micronutrients (vitamins and minerals) are required in small amounts but are essential for health, development, and growth. Micronutrient deficiencies, which affect over two billion people around the globe, are the leading cause of many ailments including mental retardation, preventable blindness, and death during childbirth. Fish is an important dietary source of micronutrients and plays important role in human nutrition. In the present investigation, micronutrient composition of 35 food fishes (includes both finfishes and shellfishes) was investigated from varying aquatic habitats. Macrominerals (Na, K, Ca, Mg) and trace elements (Fe, Cu, Zn, Mn, Se) were determined by either atomic absorption spectroscopy (AAS) or inductively coupled plasma mass spectrometry (ICP-MS)/atomic emission spectrometry (ICP-AES). Phosphorus content was determined either spectrophotometrically or by ICP-AES. Fat-soluble vitamins (A, D, E, K) were analyzed by high-performance liquid chromatography (HPLC). The analysis showed that, in general, the marine fishes were rich in sodium and potassium; small indigenous fishes (SIFs) in calcium, iron, and manganese; coldwater fishes in selenium; and the brackishwater fishes in phosphorous. The marine fishes Sardinella longiceps and Epinephelus spp. and the SIFs were rich in all fat-soluble vitamins. All these recommendations were made according to the potential contribution (daily value %) of the species to the recommended daily allowance (RDA). Information on the micronutrients generated would enhance the utility of fish in both community and clinical nutrition.

Optimization of the sublethal dose of silver nanoparticle through evaluating its effect on intestinal physiology of Nile tilapia (Oreochromis niloticus L.).

Silver nanoparticles (SNPs) are widely used in a variety of biomedical and consumer products as an antimicrobial additive. The present study was conducted to evaluate the impacts of low-dose SNPs on intestinal physiology of tilapia (Oreochromis niloticus L.) for assessing its apparent environmental risk due to extensive commercial use. SNPs were synthesized by a chemical reduction method yielding 1–27 nm oval shaped particles. Early fingerlings of tilapia were exposed with two sublethal concentrations (0.8 and 0.4 mg L−1) of SNPs for twenty one days period and its impact on the intestinal physiology was evaluated by histochemistry, catalase expression, glutamate dehydrogenase activity, SDS-PAGE and gut micro flora count. Histological analysis showed thinning of intestinal wall, swelling on mucosal layer and immunohistochemical assay exhibited an enhanced catalase expression in SNPs treated fishes. Gut microflora count elicited a dose-dependent depletion and a variable SDS-PAGE profile followed by significant (P < 0.05) elevations in glutamate dehydrogenase activity in SNPs-treated fishes. This study was designed to provide a better understanding of environmentally acceptable, dose-dependent SNPs delivery in fishes and to formulate guidelines in aquatic toxicology.

GC-MS Fingerprinting of Fatty Acids of Freshwater Mollusc LamellidensMarginalis using Different Columns, TR-Waxms and TR-FAME

GC-MS is an important instrument in lipid profiling and lipid biomarker identification. The choice of columns and detectors is important in analysis and identification of the biomolecules. In the present study, GC-MS fingerprinting of fatty acids (FAs) in different tissues of freshwater mollusc Lamellidens marginalis was carried out in GC-MS with two different columns, TR-FAME and TR-WaxMS, to examine if choice of columns and detectors influence the identifications of the lipids. These sentinel organisms are used in aquatic pollution monitoring studies as they accumulate toxic environmental contaminants to levels well above those present in the surrounding environment thus providing information on the spatio-temporal pollution trends. FAs identified in different tissues include the saturated FAs palmitic acid (C16:0), margaric acid (C17:0), stearic acid (C18:0), monounsaturated FAs (MUFAs) oleic acid (C18:1), eicosenoic acid (C20:1) and polyunsaturated fatty acid (PUFAs) linoleic acid (C18:2). More numbers of FAs were detected in TR-FAME column than TR-WaxMS column. Several non-fatty acid compounds like butylated hydroxyl toluene (BHT) and dibutyl phthalate were also identified in the FAME (fatty acid methyl ester) preparation using NIST (MS) library. It was interesting to note that the FA peaks (6/14) were outnumbered by the non-fatty acid peaks (8/14). Such compounds could be taken as unidentified FAs unless powerful detectors like MS are available and can lead to erroneous inferences. The study showed that the choice of columns and detectors influenced the identification of the compounds. The information generated on fatty acid profiles of this bivalve could serve as baseline data for this species in searching for lipid biomarkers for aquatic pollution monitoring studies.

Identification of potential biomarkers of hepatotoxicity by plasma proteome analysis of arsenic-exposed carp Labeo rohita

Arsenic (As) is a toxic environmental contaminant and potential human carcinogen. Chronic intake of arsenic-contaminated water and food leads to arsenicosis, a major public health problem in many parts of the world. Early detection of arsenic toxicity would greatly benefit patients; however, the detection of arsenicosis needs to be done early before onset of severe symptoms in which case the tools used for detection have to be both sensitive and reliable. In this context, the present study investigated plasma proteome changes in arsenic-exposed Labeo rohita, with the aim of identifying biomarkers for arsenicosis. Changes in the plasma proteome were investigated using gel-based proteomics technology. Using quantitative image analysis of the 2D proteome profiles, 14 unique spots were identified by MALDI-TOF/TOF MS and/or LC-MS/MS which included Apolipoprotein-A1 (Apo-A1) (6 spots), α-2 macroglobulin-like protein (A2ML) (2 spots), transferrin (TF) (3 spots) and warm-temperature acclimation related 65kDa protein (Wap65). The proteome data are available via ProteomeXchange with identifier PXD003404. Highly abundant protein spots identified in plasma from arsenic-exposed fish i.e. Apo-A1 (>10-fold), A2ML (7-fold) and Wap65 (>2-fold) indicate liver damage. It is proposed that a combination of these proteins could serve as useful biomarkers of hepatotoxicity and chronic liver disease due to arsenic exposure.