Heavy metals and trace minerals in commonly available shark species from North East Arabian Sea: A human health risk perspective.

Shark is a seafood commodity that is a good source of minerals and accumulates heavy metals and trace elements through biomagnification, which can pose health risk if taken above the permissible limit. A study was conducted on commonly landed eleven shark species (Scoliodon laticaudus, Rhizopriodon oligolinx, Sphyrna lewini (CR), Carcharhinus macloti, Carcharinus limbatus, Carcharhinus amblyrhynchoides, Carcharhinus sorrah, Carcharinus falciformes(VU), Glaucostegus granulatus, Chiloscyllium arabicum, Loxodon macrorhinus) and analyzed for their heavy metal content, Hazard Index, Total Hazard Quotient, Metal Pollution Index, and also calculated the health risk associated with the consumption. Most of the heavy metals and trace minerals were found to be within the acceptable limit. The Targeted Hazard Quotient (THQ) and the Hazard Index (HI) of all the species except two were less than 1 (HI ≤ 1.0). The Metal Pollution Index (MPI) is showing either no impact or very low contamination. An overall study on hazard identification and health risk characterization in terms of heavy metals shows contamination of some heavy metals in sharks, but there is no potential human health risk associated with consumption.

Effects of different cooking methods on the proximate composition and physical properties of Brown shrimp (Metapenaeus dobsonii) during cooking and freezing cycle.

Present study aimed to evaluate the changes in proximate composition and physical attributes in brown shrimp (Metapenaeus dobsonii) exposed to different methods of cooking followed by freezing. For this, three different grades (100/200, 200/300, and 300/500 numbers per kg) of brown shrimp were cooked at 90°C till the core temperature of the product reaches 85°C using hot water, steam, and microwave (400W) techniques. The changes in yield, cooking loss, proximate composition, textural, and colour profile were assessed for cooked shrimps. The cooking loss was higher for larger grades of shrimp, whereas shrimp cooked using hot water exhibited the highest cooking loss. Lowest cooking loss was observed for microwave-cooked shrimp. Moisture content decreased after cooking whereas protein, fat, ash, and calorie content increased. After cooking, different grades of shrimp showed an increase in their lightness (L*), redness (a*), and yellowness (b*) values. The smaller grade shrimp exhibited lower value for cohesiveness, hardness, chewiness, and gumminess. Different cooking techniques yielded cooked shrimp of varying hardness values.

Current trends in solid tannery waste management.

The tannery is one of the leading revenue-generating sectors in developing countries. The ever-increasing demand for leather products in the global market requires converting large amounts of rawhide/skins into resilient non-putrescible finished leather. Only 20% of the raw material is converted into a finished product; the rest 80% is discarded as solid and liquid wastes during leather processing. A heavy discharge of improperly treated solid tannery waste (STW) causes a severe impact on the surrounding environment by polluting soil, surface water, and groundwater resources, posing severe hazards to human and animal health. STW comprises proteinaceous untanned and tanned waste, which requires proper treatment for eco-friendly disposal. Several strategies have been developed over the years for the reduction and recycling of STW for producing renewable energy (biogas and biohydrogen), biofuels (biodiesel and briquettes), construction material, fertilizers, commercial products (adsorbents, animal feeds, proteins, fats, and enzymes), and biodegradable packaging and non-packaging materials. In this review, we discuss various strategies adopted for recycling, reutilization, and reduction of STW in an environment-friendly manner. Furthermore, an overview of the current perspectives toward achieving a zero-waste policy is also presented to reduce the environmental burden using green-clean technology to aid the survival of present-day tanneries.

RGS7-ATF3-Tip60 Complex Promotes Hepatic Steatosis and Fibrosis by Directly Inducing TNFα.

Aims: The pathophysiological mechanism(s) underlying non-alcoholic fatty liver disease (NAFLD) have yet to be fully delineated and only a single drug, peroxisome proliferator-activated receptor (PPAR) α/γ agonist saroglitazar, has been approved. Here, we sought to investigate the role of Regulator of G Protein Signaling 7 (RGS7) in hyperlipidemia-dependent hepatic dysfunction. Results: RGS7 is elevated in the livers of NAFLD patients, particularly those with severe hepatic damage, pronounced insulin resistance, and high inflammation. In the liver, RGS7 forms a unique complex with transcription factor ATF3 and histone acetyltransferase Tip60, which is implicated in NAFLD. The removal of domains is necessary for ATF3/Tip60 binding compromises RGS7-dependent reactive oxygen species generation and cell death. Hepatic RGS7 knockdown (KD) prevented ATF3/Tip60 induction, and it provided protection against fibrotic remodeling and inflammation in high-fat diet-fed mice translating to improvements in liver function. Hyperlipidemia-dependent oxidative stress and metabolic dysfunction were largely reversed in RGS7 KD mice. Interestingly, saroglitazar failed to prevent RGS7/ATF3 upregulation but it did partially restore Tip60 levels. RGS7 drives the release of particularly tumor necrosis factor α (TNFα) from isolated hepatocytes, stellate cells and its depletion reverses steatosis, oxidative stress by direct TNFα exposure. Conversely, RGS7 overexpression in the liver is sufficient to trigger oxidative stress in hepatocytes that can be mitigated via TNFα inhibition. Innovation: We discovered a novel non-canonical function for an R7RGS protein, which usually functions to regulate G protein coupled receptor (GPCR) signaling. This is the first demonstration for a functional role of RGS7 outside the retina and central nervous system. Conclusion: RGS7 represents a potential novel target for the amelioration of NAFLD. Antioxid. Redox Signal. 38, 137-159.

Hepatic Regulator of G Protein Signaling 6 (RGS6) drives non-alcoholic fatty liver disease by promoting oxidative stress and ATM-dependent cell death.

The pathophysiological mechanism(s) driving non-alcoholic fatty liver disease, the most prevalent chronic liver disease globally, have yet to be fully elucidated. Here, we identify regulator of G protein signaling 6 (RGS6), up-regulated in the livers of NAFLD patients, as a critical mediator of hepatic steatosis, fibrosis, inflammation, and cell death. Human patients with high hepatic RGS6 expression exhibited a corresponding high inflammatory burden, pronounced insulin resistance, and poor liver function. In mice, liver-specific RGS6 knockdown largely ameliorated high fat diet (HFD)-driven oxidative stress, fibrotic remodeling, inflammation, lipid deposition and cell death. RGS6 depletion allowed for maintenance of mitochondrial integrity restoring redox balance, improving fatty acid oxidation, and preventing loss of insulin receptor sensitivity in hepatocytes. RGS6 is both induced by ROS and increases ROS generation acting as a key amplification node to exacerbate oxidative stress. In liver, RGS6 forms a direct complex with ATM kinase supported by key aspartate residues in the RGS domain and is both necessary and sufficient to drive hyperlipidemia-dependent ATM phosphorylation. pATM and markers of DNA damage (γH2AX) were also elevated in livers from NAFLD patients particularly in samples with high RGS6 protein content. Unsurprisingly, RGS6 knockdown prevented ATM phosphorylation in livers from HFD-fed mice. Further, RGS6 mutants lacking the capacity for ATM binding fail to facilitate palmitic acid-dependent hepatocyte apoptosis underscoring the importance of the RGS6-ATM complex in hyperlipidemia-dependent cell death. Inhibition of RGS6, then, may provide a viable means to prevent or reverse liver damage by mitigating oxidative liver damage.

G protein ß5-ATM complexes drive acetaminophen-induced hepatotoxicity.

Excessive ingestion of the common analgesic acetaminophen (APAP) leads to severe hepatotoxicity. Here we identify G protein ß5 (Gß5), elevated in livers from APAP overdose patients, as a critical regulator of cell death pathways and autophagic signaling in APAP-exposed liver. Liver-specific knockdown of Gß5 in mice protected the liver from APAP-dependent fibrosis, cell loss, oxidative stress, and inflammation following either acute or chronic APAP administration. Conversely, overexpression of Gß5 in liver was sufficient to drive hepatocyte dysfunction and loss. In hepatocytes, Gß5 depletion ameliorated mitochondrial dysfunction, allowed for maintenance of ATP generation and mitigated APAP-induced cell death. Further, Gß5 knockdown also reversed impacts of APAP on kinase cascades (e.g. ATM/AMPK) signaling to mammalian target of rapamycin (mTOR), a master regulator of autophagy and, as a result, interrupted autophagic flux. Though canonically relegated to nuclear DNA repair pathways, ATM also functions in the cytoplasm to control cell death and autophagy. Indeed, we now show that Gß5 forms a direct, stable complex with the FAT domain of ATM, important for autophosphorylation-dependent kinase activation. These data provide a viable explanation for these novel, G protein-independent actions of Gß5 in liver. Thus, Gß5 sits at a critical nexus in multiple pathological sequelae driving APAP-dependent liver damage.

NGS-based characterization of microbial diversity and functional profiling of solid tannery waste metagenomes.

Tanneries pose a serious threat to the environment by generating large amount of solid tannery waste (STW). Two metagenomes representing tannery waste dumpsites Jajmau (JJK) and Unnao (UNK) were sequenced using Illumina HiSeq platform. Microbial diversity analysis revealed domination of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, and Planctomycetes in both metagenomes. Presence of pollutant degrading microbes such as Bacillus, Clostridium, Halanaerobium and Pseudomonas strongly indicated their bioremediation ability. KEGG and SEED annotated main functional categories included carbohydrate metabolism, amino acids metabolism, and protein metabolism. KEGG displayed 5848 and 9633 proteases encoding ORFs compared to 5159 and 8044 ORFs displayed by SEED classification in JJK and UNK metagenomes, respectively. Abundantly present serine- and metallo-proteases belonging to Bacillaceae, Clostridiaceae, Xanthomonadaceae, Flavobacteriaceae and Chitinophagaceae families exhibited proteinaceous waste degrading ability of these metagenomes. Further structural and functional analysis of metagenome encoded enzymes may facilitate the discovery of novel proteases useful in bioremediation of STW.

An improved method suitable for isolation of high-quality metagenomic DNA from diverse soils.

Standardization of metagenomic DNA extraction protocol is a pre-requisite for a successful metagenomic study aiming to screen and exploit the variety of microorganisms inhabiting a particular soil environment. Six methods reported earlier were used for isolation of metagenomic DNA in the present study. These methods suffered with regard to either poor yield or quality of DNA. Therefore, we developed an improved method for isolation of high-molecular weight and good quality metagenomic DNA from different soil samples. Our protocol combines the enzymatic (lysozyme and proteinase K) and chemical (CTAB and CaCl2) strategies to ensure efficient cell lysis and use of PEG and isopropanol for precipitation of humic impurities-free DNA. Our improved method gave high yield of good quality metagenomic DNA from diverse soils collected from garden, domestic waste dumping site, cellulose waste dumping site, sewage site, and tannery waste site. The good quality of the metagenomic DNA was evident by spectrophotometry data, PCR amplification of 16S rRNA gene and restriction digestion.

Activation of Checkpoint Kinase Chk1 by Reactive Oxygen Species Resulting from Disruption of wat1/pop3 in Schizosaccharomyces pombe.

DNA double-strand breaks are critical lesions that can lead to chromosomal aberrations and genomic instability. In response to DNA damage, Chk1, a serine/threonine kinase, is responsible for cell cycle arrest to prevent damaged cells from progressing through the cell cycle. Here, we report that the disruption of wat1, a WD repeat-containing protein, leads to the phosphorylation of Chk1. The double-deletion of chk1 and wat1 had a grave effect on the survival of fission yeast cells, and the spontaneous recombination rate was also high upon double-deletion of wat1 and chk1, as compared to the single-mutant. In the absence of wat1, the cells exhibited a high level of nuclear fragmentation that resulted in the accumulation of Rad22 yellow fluorescent protein foci. Furthermore, we show that wat1 is required for the regulation of the oxidative stress response. We observed elevated levels of reactive oxygen species (ROS) generation in wat1-null mutant that led to a high degree of propidium iodide staining at nonpermissive temperature. Based on the results presented here, we hypothesize that ROS production in wat1-null mutant cells generates DNA fragmentation that could trigger a checkpoint response and that, in the absence of checkpoint kinase Chk1, the cells exhibit severe growth defects leading to a synthetic lethal phenotype.

Wat1/pop3, a conserved WD repeat containing protein acts synergistically with checkpoint kinase Chk1 to maintain genome ploidy in fission yeast S. pombe.

Aberrant chromosome segregation defects can lead to aneuploidy, a common characteristic of human solid tumors. Aneuploidy is generated due to defects in the mitotic spindle or due to inefficient mitotic checkpoint response. We have isolated a novel mutant allele of wat1, a WD repeat containing protein that exhibits conditional synthetic lethality with chk1 knock out. We observed only a marginal decrease in the level of α tubulin protein level in wat1-17 mutants after prolong exposure at semi permissive temperature. Interestingly the protein level of α-tubulin was reduced in the chk1Δ wat1-17 double mutant at 18°C with defective microtubule structure. Consistent with loss of microtubule structure in the chk1 deletion background, the double mutant of wat1-17 chk1Δ was hypersensitive to the microtubule destabilizing agent TBZ suggesting severe defects in microtubule integrity in wat1-17 mutant in the absence of Chk1. Combination of wat1-17 with the chk1 deletion also aggravates the defects in the maintenance of genome ploidy. The mutation in wat1-17 was mapped to Cys 233 that was changed to tyrosine. Based on the molecular modeling studies, we hypothesize that the substitution of the bulky Tyr residue at Cys233 position in wat1-17 mutant results in conformational changes. This in turn can affect its intercations with other interacting partners and perturb the overall functions of the Wat1 protein.

DNA topoisomerase 2 mutant allele mildly delays the mitotic progression and activates the checkpoint protein kinase Chk1 in fission yeast Schizosaccharomyces pombe.

DNA topoisomerases are specialized nuclear enzymes that perform topological modifications on double-stranded DNA (dsDNA) and hence are essential for DNA metabolism such as replication, transcription, recombination, condensation and segregation. In a genetic screen, we identified a temperature-sensitive mutant allele of topoisomerase 2 that exhibits conditional synthetic lethality with a chk1 knockout strain. The mutant allele of topoisomerase 2 is defective in chromosome segregation at a non-permissive temperature and there was increase in chromosome segregation defects in the double mutant of top2-10 and chk1 delete at a non-permissive temperature. More importantly, topoisomearse 2 mutant cells mildly delay the mitotic progression at non-permissive temperature that is mediated by checkpoint protein kinase Chk1. Additionally, top2-10 mutant cells also activate the Chk1 at a non-permissive temperature and this activation of Chk1 takes place at the time of mitosis. Interestingly, top2-10 mutant cells retain their viability at a non-permissive temperature if the cells are not allowed to enter into mitosis. Taking together our results, we speculate that in the top2-10 mutant, the segregation of entangled chromatids during mitosis could result in delaying the mitotic progression through the activation of Chk1 kinase.