Catechin and Catechin Fractions as Biochemical Markers to Study the Diversity of Indian Tea (Camellia sinensis (L.) O. Kuntze) Germplasm

The heterogeneous Indian tea germplasm includes ‘China’, ‘Assam’, ‘Cambod’, and their hybrids which were evaluated using biochemical markers viz., total catechin and their fractions, for varietal identification and characterization. Principal component analysis (PCA) of biochemical characters showed that the total catechin and trihydroxylated catechin has higher eigenvalues. The first two principal components (PCs) could differentiate more than 90% of the clones studied. This grouping based on first two principal component matrices differentiated ‘China’, and their hybrids with ‘Assam’ and ‘Cambod’ variety. Morphologically indistinct large‐leaved ‘Cambod’ variety and ‘Assam’ varieties could not be differentiated using biochemical markers, since both varietal types taxonomically belong to a single species. Clones of ‘China’ type showed low total catechin content and catechin ratio which are distinctly grouped. The ‘China–Assam’ and ‘China–Cambod’ hybrids formed intermediate groups between ‘China’ PC group and ‘Cambod’/‘Assam’ PC groups, providing evidence for genetic control of catechin ratio variation. Tea clones which are differentially positioned in the PC group could be explained based on the genetic contribution by other varietal type as parents. This biochemical characterization will be a useful tool in the development of quality‐tea clones with different proportion of total catechin and their fractions.     

Cell‐specific differences in the processing of the R14W CAIV mutant associated with retinitis pigmentosa 17

Retinitis pigmentosa is a highly heterogeneous form of inherited blindness which affects more than 1.3 million individuals worldwide. The RP17 form of the disease is caused by an arginine to tryptophan (R14W) mutation in the signal sequence of carbonic anhydrase IV (CAIV). While CAIV is expressed in the choriocapillaries of the eye and renal epithelium, the R14W mutation results in an exclusively ocular phenotype in affected individuals. In order to investigate the mechanism of disease in RP17 and the lack of kidney phenotype, we compared the subcellular localization and post‐translational processing of wild‐type (WT)‐ and mutant‐CAIV in three cell types. We show using immunocytochemistry that unlike WT CAIV which is transported to the plasma membrane of transfected COS‐7 and HT‐1080 cells, the R14W mutant CAIV is retained in the endoplasmic reticulum. Western blot analyses further reveal that whereas the WT CAIV is processed to its mature form in both these cell lines, significant levels of the R14W mutant protein remain in its immature form. Importantly, flow cytometry experiments demonstrate that compared to WT CAIV protein, expression of specifically the R14W CAIV results in an S and G2/M cell‐cycle block, followed by apoptosis. Interestingly, when the above experiments were repeated in the human embryonic kidney cell line, HEK‐293, strikingly different results were obtained. These cells were unaffected by the expression of the R14W mutant CAIV and were able to process the mutant and WT protein equally effectively. This study has important implications for our understanding of the RP17 phenotype. J. Cell. Biochem. 111: 735–741, 2010. © 2010 Wiley‐Liss, Inc.     

Proteome analysis of Azotobacter vinelandii ∆arrF mutant that overproduces poly-β-hydroxybutyrate polymer

Azotobacter vinelandii ArrF is an iron-responsive small RNA that is under negative control of Ferric uptake regulator protein. A. vinelandii ∆arrF mutant that had a deletion of the entire arrF gene was known to overproduce poly-β-hydroxybutyrate (PHB). Proteins differentially expressed in the mutant were identified by gel-based proteomics and confirmed by real-time RT-PCR. 6-Phosphogluconolactonase and E₁ component of pyruvate dehydrogenase complex, which leads to the production of NADPH and acetyl-CoA, were upregulated, while proteins in the tricarboxylic acid cycle that consumes acetyl-CoA were downregulated. Heat-shock proteins such as HSP20 and GroEL were highly overexpressed in the mutant. Antioxidant proteins such as Fe-containing superoxide dismutase (FeSOD), a putative oxidoreductase, alkyl hydroperoxide reductase, flavorprotein WrbA, and cysteine synthase were also overexpressed in the ∆arrF mutant, indicating that the PHB accumulation is stressful to the cells. Upregulated in the ∆arrF mutant were acetyl-CoA carboxylase, flagellin, and adenylate kinase, though the reasons for their overexpression are unclear. Among genes upregulated in the mutant, sodB coding for FeSOD and phbF encoding PHB synthesis regulator PhbF were negatively regulated by small RNA ArrF probably in an antisense mechanism. The deletion of arrF gene, therefore, would increase PhbF and FeSOD levels, which favors PHB synthesis in the mutant. On the other hand, glutamate synthetase, elongation factor-Tu, iron ABC transporter, and major outer membrane porin OprF were downregulated in the ∆arrF mutant. Based on the results, it is concluded that multiple factors including the direct effect of small RNA ArrF might be responsible for the PHB overproduction in the mutant.     

Identification and validation of genes involved in gastric tumorigenesis

Background  

Gastric cancer is one of the common cancers seen in south India. Unfortunately more than 90% are advanced by the time they report to a tertiary centre in the country. There is an urgent need to characterize these cancers and try to identify potential biomarkers and novel therapeutic targets.     

Computational analysis of candidate disease genes and variants for salt-sensitive hypertension in indigenous Southern Africans

Multiple factors underlie susceptibility to essential hypertension, including a significant genetic and ethnic component, and environmental effects. Blood pressure response of hypertensive individuals to salt is heterogeneous, but salt sensitivity appears more prevalent in people of indigenous African origin. The underlying genetics of salt-sensitive hypertension, however, are poorly understood. In this study, computational methods including text- and data-mining have been used to select and prioritize candidate aetiological genes for salt-sensitive hypertension. Additionally, we have compared allele frequencies and copy number variation for single nucleotide polymorphisms in candidate genes between indigenous Southern African and Caucasian populations, with the aim of identifying candidate genes with significant variability between the population groups: identifying genetic variability between population groups can exploit ethnic differences in disease prevalence to aid with prioritisation of good candidate genes. Our top-ranking candidate genes include parathyroid hormone precursor (PTH) and type-1 angiotensin II receptor (AGTR1). We propose that the candidate genes identified in this study warrant further investigation as potential aetiological genes for salt-sensitive hypertension.     

Prevalence of human papillomavirus infection among young women in North India

Background: The number of women infected with human papillomavirus (HPV) and the distribution of the HPV genotypes vary across populations and with age. Objective: To determine the prevalence and genotype distribution of HPV in young married women aged 16–24 years. Methods: 1300 women residing in an urban slum in Delhi donated samples of exfoliated cervical cells that were collected by the Digene^® kit and tested for the presence of HPV DNA by two techniques in parallel, i.e., PCR using PGMY consensus primers for all HPV types and the Digene HPV test (Hybrid Capture 2 (HC2) Probe B for high-risk (hr) types. Genotyping was done on all HPV positive samples using the Roche reverse line blot assay. Results: HPV infection was detected in 91/1300 (7%) samples by PCR and 110/1300 (8.4%) samples by HC2. Genotyping identified 20 high-risk and 11 low-risk types. HPV16 was the commonest high-risk type (3%) followed by HPV52 (1.2%) and HPV51 (0.8%). Among low-risk types, HPV62 was the commonest (0.8%), followed by HPV84 and HPV89 (0.5% each). Multiple infections were found in 3% of the HPV positive samples. Conclusion: A wide spectrum of HPV genotypes is seen in this young population. Knowledge about HPV types prevalent in communities in different regions of India would be useful in devising the optimum strategy for cervical cancer prevention.     

Enhanced gluconeogenesis and hepatic insulin resistance in insulin-like growth factor binding protein-1 transgenic mice

Fasting hyperglycemia is observed in transgenic mice which overexpress insulin-like growth factor binding protein-1. In an attempt to understand the mechanisms underlying this observation we have examined glycogenolysis and gluconeogenesis in isolated hepatocytes from wild-type and transgenic mice. Glucose production from pyruvate was significantly less responsive to inhibition by insulin in hepatocytes from transgenic mice compared to hepatocytes from wild-type mice. Serum from transgenic mice resulted in more glucose production by hepatocytes than serum from wild-type mice. Serum alanine was increased while serum lactate was significantly reduced in transgenic mice compared to wild-type mice. Serum free fatty acids and beta-hydroxybutyrate were similar in both groups of mice. These data suggest that fasting hyperglycemia is due to enhanced gluconeogenesis, hepatic insulin resistance and increased serum gluconeogenic substrate in transgenic mice.     

Single additional methylene group in the head-group region imparts high gene transfer efficacy to a transfection-incompetent cationic lipid

The tobacco ntf4 mitogen-activated protein (MAP) kinase gene (and its encoded protein p45^Ntf4) is expressed at later stages of pollen maturation. We have found that the highly related MAP kinase SIPK is also expressed in pollen and, like p45^Ntf4, is activated upon pollen hydration. The MAP kinase kinase NtMEK2 activates SIPK, and here we show that it can also activate p45^Ntf4. In an attempt to inhibit the function of both MAP kinases simultaneously we constructed a loss-of-function mutant version of NtMEK2, which, in transient transformation assays, led to an inhibition of germination in the transformed pollen grains. These data indicate that NtMEK2, and by inference its substrates p45^Ntf4 and/or SIPK, are involved in pollen germination.     

Monoclonal gammopathies of undetermined significance

The term 'monoclonal gammopathy of undetermined significance' denotes the presence of a monoclonal protein in patients without evidence of multiple myeloma, macroglobulinemia, amyloidosis or related plasma cell proliferative disorders. The disorder has been found in approximately 3% of persons older than 70 years and in approximately 1% of persons older than 50 years. A population-based study included 1384 patients from south-eastern Minnesota who had the disorder diagnosed at the Mayo Clinic from 1960 through 1994. Risk of progression was about 1% per year, but patients were at risk of progression even after 25 years or more of stable monoclonal gammopathy of undetermined significance. The risk for development of multiple myeloma was increased 25-fold; the risk of macroglobulinemia, 46-fold; and the risk of primary amyloidosis, 8.4-fold. Concentration and type of monoclonal protein were the only independent predictors of progression. The presence of a urine monoclonal protein and the reduction of one or more uninvolved immunoglobulins were not risk factors for progression. Monoclonal gammopathy of undetermined significance may be associated with various disorders, including lymphoproliferative diseases, leukemia, von Willebrand disease, connective tissue diseases and neurologic disorders.