Indian journal of biochemistry & biophysics最新文献

Study was carried out to understand and compare architecture of the proteins of erythrocyte cell surface of some mammals viz., Homo sapiens (human), Sus scorfa domestica (pig) and Bos taurus domestica (cow). In this study, we investigated the action of proteinases viz., trypsin and chymotrypsin and neuraminidase on the erythrocyte surface proteins and erythrocyte agglutination tendency with a lectin (concanavalin A). The electrophoretic pattern of membrane proteins and glycophorins (analyzed by SDS-PAGE and visualized by Coomassie brilliant blue and periodic acid-schiff stains, respectively) and concanavalin A (Con A) agglutinability revealed that: (i) There were variations in the number and molecular weights of glycophorins in human, pig and cow, (ii) trypsin action on pig and cow erythrocyte membrane proteins was similar, unlike human, (iii) glycophorins degradation by trypsin and chymotrypsin was not similar in pig, as compared to that of human and cow, (iv) erythrocytes agglutination with Con A was significantly different due to differences in membrane composition and alterations in the surface proteins after enzyme treatment, (v) a direct correlation was found between degradation of glycophorins and Con A agglutinability, and (vi) removal of erythrocyte surface sialic acids by neuraminidase specifically indicated an increase in Con A agglutinability of pig and cow erythrocytes, similar to human.

The distribution of chlorophyll-related compounds (CRCs) derived from dietary spinach was investigated in different organs the rabbits. The rabbits in the experimental group consumed 100 g of freeze-dried spinach powder after a 24 h fasting period and sacrificed 2, 4, 8, 12 and 24 h later and in the control group sacrificed after the 24 h fasting period. The main CRCs in the liver were found to be chlorophyll (Chl a) and b, chlorophyllide (Chlide) a and b, pheophytin (Phe) a and b and pheophorbide (Pho) a and b, which reached their peak values at 8 h post-feeding. The gallbladder contained mainly Chlide a and a', Pho a and a', Pho b and b', which peaked their values at 2 h post-feeding. Pho a and b were consistently observed in the blood and peaked at 12 h post-feeding. The earlier appearance of Chlide a', Pho a' and Pho b' in the gallbladder compared to the liver indicated that these CRCs were compartmentalized differently and might undergo the same type of vectorialized transport as characterized for the bile salts. Pho levels peaked later in the blood compared to the liver, suggesting that Pho might be released into the peripheral blood circulation from the liver. In conclusion, Chlide and Pho were the principal Chl metabolites in the rabbits. Our data may expand our understanding of the metabolism and biodistribution of CRCs in the human body. A number of biological functions, including anti-oxidation, anti-tumor and anti-aging have recently been attributed to CRCs, it will be interesting to explore, if the binding of Chlide and Pho to other nutrients or trace metal ions in the body mediate their biological functions.

Previous studies have shown that COP1 (constitutive photomorphogenic 1) protein of Arabidopsis thaliana plays a crucial role in different aspects of photomorphogenesis. Interaction of COP1 with SPA1 (suppressor of phytochrome A) and other regulatory proteins actively affect light regulatory gene expression in diverse directions. Though several studies have explained the function of COP1 protein, method of its interaction with SPA1 and cryptochromes are still not explained in detail. In this study, in silico analysis was followed to predict the tertiary structure, active site residues, functionally important regions and regular expressions of COP1 protein. Its ease of its interaction with SPA1 and seven other regulatory proteins, namely bZIP transcription factor 56 (HY5), transcription factor HY5-like (HYH), serine/threonine-protein phosphatase 7 (AtPP7), protein long hypocotyl in FAR-RED 1 (HFR1), OBP3-responsive protein 1 (OBP3), transcription factor MYC2 (MYC2/ZBF1) and Z-box binding factor 2 protein (GBF1/ZBF2) was measured using protein-protein docking. Interaction with MYC2 was found to be stronger than with others with a global energy value of -22.46. It was also found that COP1 shared three regions of regular expression with SPA1, the last expression also being present in MYC2/ZBF1 and OBP3. Taken together, the insight into structural and functional properties of COP1 protein presented in this study would be helpful in determining the role of COP1 in unknown mechanisms of photomorphogenesis.

The involvement of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and contents of H2O2, malondialdehyde (MDA) and proline was investigated in determining salinity tolerance among seedlings of thirty chickpea (Cicer arietinum L.) genotypes having different pedigrees. Chickpea genotypes, including cultivars and advanced lines were grown for 7 days under control and salt stress (50 mM NaCl) conditions. The genotypes showed differential response to salt stress in terms of growth, DPPH radical scavenging activity and contents of H2O2, MDA and proline in seedlings. On the basis of seedling growth, the genotypes having better performance under stress conditions had reduced levels of H2O2 and MDA contents, but increased levels of proline and DPPH radical scavenging activity. Stress tolerance index for these parameters was also determined. Agglomerative hierarchal clustering by Pearson correlation coefficient grouped the genotypes into two major clusters--MC I and MC II. MC II and Al-1 sub-cluster of MC-I comprised mainly of genotypes that showed higher stress resistance levels for the respective parameters in comparison to genotypes in other sub-clusters. Thus, it is possible to identify salt-tolerant genotypes on the basis of above parameters without a field trial.

The phytochemicals present in the grapes are responsible for nutraceutical and health benfits due to their antioxidant properties. These phytochemicals, however, vary greatly among different cultivars. In this study, we evaluated the antioxidant potential and protective role of four different Indian grape (Vitis vinifera) cultivars extracts, namely Flame seedless (Black grapes), Kishmish chorni (Black with reddish brown), Red globe (Red) and Thompson seedless mutant (Sonaka, Green) against the Fenton-like reagent (200 μmole H2O2, 2 mmole ascorbate, 25 μmole FeSO4)-induced liver damage. Non-enzymatic antioxidants, such as glutathione (GSH) levels and activities of antioxidant enzymes, such as glutathione S-transferase (GST) and superoxide dismutase (SOD), as well as total antioxidant capacity (TAC) were highest in the grape seed, followed by skin and pulp. Among edible parts of different cultivars, skin of Flame seedless (Black) cultivar showed highest antioxidant potential, while the Thompson seedless the least potential. These antioxidants were found to be significantly (P < 0.01) correlated with the levels of total phenol, flavonoids and ascorbic acid. Fenton-like reagent treatment significantly (P < 0.001) decreased GSH content by 39.1% and activities of catalase (CAT) by 43.2% and glutathione reductase (GR) by 60%, while increasing thiobarbituric acid reactive substances (TBARS) and nitric oxide levels by 2.13-fold and 0.64-fold, respectively and GST activity by 0.81-fold. Pre-treatment with grape seed extracts showed the best hepatoprotective action against Fenton-like reagent-induced damage, followed by the extracts of skin and pulp of any cultivar. Thus, our study showed the significant amounts of antioxidants were in grape seed, followed by its skin and pulp, which varied among the cultivars and was associated with the protective action of grape extracts against Fenton-like reagent-induced liver damage ex-vivo.

In vitro anticancer potential of methanolic and aqueous extracts of whole plants of Mentha arvensis, M. longifolia, M. spicata and M. viridis at concentration of 100 μg/ml was evaluated against eight human cancer cell lines--A-549, COLO-205, HCT-116, MCF-7, NCI-H322, PC-3, THP-1 and U-87MG from six different origins (breast, colon, glioblastoma, lung, leukemia and prostate) using sulphorhodamine blue (SRB) assay. Methanolic extracts of above-mentioned Mentha Spp. displayed anti-proliferative effect in the range of 70-97% against four human cancer cell lines, namely COLO-205, MCF-7, NCI-H322 and THP-1; however, aqueous extracts were found to be active against HCT-116 and PC-3. The results indicate that Mentha Spp. contain certain constituents with cytotoxic properties which may find use in developing anticancer agents.

Antioxidant enzymes, besides being involved in various developmental processes, are known to be important for environmental stress tolerance in plants. In this study, the effect of treatment of 2.5 mM putrescine (Put), heat stress (HS -42 degrees C for 2 h) and their combination on the expression and activity of antioxidant enzymes was studied at pre-anthesis in the leaves of two wheat (Triticum aestivum L.) cultivars--HDR77 (thermotolerant) and HD2329 (thermosusceptible). We observed that 2.5 mM Put before HS significantly enhanced the transcript levels of superoxide dismutase (SOD), catalase (CAT), cytoplasmic and peroxisomal ascorbate peroxidase (cAPX, pAPX) in both the cultivars. However, the activities of antioxidant enzymes (SOD, CAT, APX and GR), as well as accumulation of antioxidants (ascorbic acid and total thiol content) were higher in HDR77 than in HD2329 in response to the treatment 2.5 mM Put + HS. No significant change was observed in the proline accumulation in response to HS and combined treatment of 2.5 mM Put + HS. A decrease in the H2O2 accumulation, lipid peroxidation and increase in cell membrane stability (CMS) were observed in response to 2.5 mM Put + HS treatment, as compared to HS treatment alone in both the cultivars; HDR77 was, however, more responsive to 2.5 mM Put + HS treatment. Put (2.5 mM) treatment at pre-anthesis thus modulated the defense mechanism responsible for the thermotolerance capacity of wheat under the heat stress. Elicitors like Put, therefore, need to be further studied for temporarily manipulating the thermotolerance capacity of wheat grown under the field conditions in view of the impending global climate change.

The non-proteinogenic amino acids--phenylglycine (PG) and hydroxyphenylglycine (HPG) are crucial components of certain peptidic natural products and are important for the preparation of various medicines. In this, study, the conformation of model dipeptides Ac-X-NHMe of PG, p-HPG and 3, 5-di-hydroxyphenylglycine (3, 5-DHPG) was studied both in R and S form by quantum mechanical (QM) and molecular dynamics approaches. On the energy scale, the conformational states of these molecules in both the R and S were found to be degenerate by QM studies, stabilized by non-covalent interactions like carbonyl--carbonyl interactions, carbonyl-lp .. π (aromatic ring) interactions etc. These interactions disappeared/weakened due to interaction of water molecules with carbonyl groups of backbone in simulation and water was found to interact with the aromatic ring through O(w)-H .. π or O(w)lp .. π interactions. The degeneracy of conformational states was lifted in favor of R-form of PG and DHPG and water molecules interactions with aromatic ring led to non-planarity of the aromatic ring. In simulation studies, irrespective of the starting geometry, the Φ, ψ values for the R form correspond to inverse β/inverse collagen region and for the S-form, the Φ, ψ values correspond to β/collagen region i.e., adopt single conformation. The obtained results were in conformity with the CD spectroscopic data on D-PG and D-p-HPG. The conformational behavior of the unusual amino acids might be of great help in designing of bioactive peptides/peptide based drugs to be realized in single conformation--an essential requirement.

Perception of molecular mechanism would provide potent additional knowledge on mammalian membrane proteins involved in causing diseases. In human, syntaxin-3 (STX3) is a significant apical targeting protein in the epithelial membrane and in exocytosis process; it also acts as a vesicle transporter by cellular receptor in neutrophils, which is crucial for protein trafficking event. Structurally, syntaxin-3 has hydrophobic domain at carboxyl terminus that directs itself to intra-cellular compartments. In addition, the experimental structure of STX3 is not available and no mutational study has been carried out with natural variants of proteins. Moreover, there is no evidence so far for the natural variant Val286 of STX3 causing any diseases. Hence, in the present study, analyses of residue-based properties of the homology model STX3 were carried out along with mutations at carboxyl terminus of STX3 by implementing protein engineering and in silico approaches. The model structure of STX3 was constructed adopting Modeller v9.11 and the aggregation propensity was analyzed with BioLuminate tool. The results showed that there was reduction in aggregation propensity with point mutation at Val286, instead of Ile, resulting into increasing the structural stability of STX3. In conclusion, the Ccap exposed residue would be a suitable position for further mutational studies, particularly with Val286 of STX3 in human. This approach could gainfully be applied to STX3 for efficient drug designing which would be a valuable target in the cancer treatment.

Anticancer potential of Piper longum fruit against human cancer cell lines (DU-145 prostate, A549 lung, THP-1 leukemia, IGR-OVI-1 ovary and MCF-7 breast) as well as its in vitro and in vivo biochemical efficacy in A1Cl3-induced hepatotoxicity were evaluated in the rats. Dried samples were extracted with several solvents using soxhlet apparatus. Flavonoid content in chloroform, benzene, ethyl alcohol and aqueous extracts of fruit was 19, 14, 12 and 11 μg quercetin equivalent/mg of sample, respectively. Hexane extracts exhibited 90-92% cytotoxicity against most of the test cell lines (A549, THP-1, IGR-OVI-1 and MCF-7), while benzene extract displayed 84-87% cytotoxicity against MCF-7, IGR-OV-1 and THP-1 cell lines. Among extracts, hexane, benzene and acetone extracts demonstrated considerable cytotoxicity (91-95%) against A549 (lung cancer) cell line in Sulforhodamine B dye (SRB) assay. Cell cycle analysis revealed that hexane, benzene and acetone extracts produced 41, 63 and 43% sub-G1 DNA fraction, demonstrating cell cycle inhibitory potential of these extracts against A549 cell line. Chloroform, ethyl alcohol and aqueous extracts displayed 71, 64 and 65% membrane protective activity, respectively in lipid peroxidation inhibition assay. P. longum fruit extracts also ameliorated A1Cl3-induced hepatotoxicity, as indicated by alterations observed in serum enzymes ALP, SGOT and SGPT activity, as well as creatinine and bilirubin contents. In conclusion, study established the cytotoxic and hepatoprotective activity in P. longum extracts.