PubMed Health⌕ Search

Biomedical subjects

G Chandra

Publications and source records attributed to G Chandra.

At least 19 recordsLinked to original sources
PubMed2004

Effect of vitamin D3 on phagocytic potential of macrophages with live Mycobacterium tuberculosis and lymphoproliferative response in pulmonary tuberculosis.

Immune responses are elicited through antigen presentation and recognition by macrophages and T-lymphocytes, respectively. The immunomodulatory effect of vitamin D(3) on macrophage phagocytic potential with live Mycobacterium tuberculosis, spontaneous and M. tuberculosis culture filtrate antigen induced lymphocyte responses were studied in pulmonary tuberculosis patients (PTBPs) ( n = 31) and normal healthy subjects (NHSs) ( n = 43). Vitamin D(3) at a concentration of 10(-7) M significantly enhanced the macrophage phagocytosis of live M. tuberculosis in normal subjects with low phagocytic potential (less than 10%) ( p = 0.015). No such increase was observed in PTBPs. Vitamin D(3) significantly decreased the spontaneous lymphoproliferative response ( p = 0.022) and increased the apoptosis of peripheral blood mononuclear cells in PTBPs ( p = 0.024). In normals, vitamin D(3) increased the spontaneous lymphoproliferative response. An inverse correlation between macrophage phagocytosis and spontaneous response was observed in NHSs, whereas a direct correlation was seen between vitamin D(3)-treated cells in normal subjects under in vitro condition. Vitamin D(3) decreased the M. tuberculosis culture filtrate antigen induced lymphocyte response significantly in normal subjects ( p = 0.0003), while it had no influence on the lymphocyte response in PTBPs. The present study suggests that exposure to vitamin D(3) increases the phagocytic potential and spontaneous lymphoproliferative response but brings down the antigen-induced response in normals. In tuberculosis, addition of vitamin D(3) has no significant effect on antigen-induced lymphoproliferative response. This may be due to the unresponsive nature of the cells to the action of vitamin D(3) by virtue of the disease, which renders them inactive.

Apoptosis↗
PubMed2004

Regulatory role of vitamin D receptor gene variants of Bsm I, Apa I, Taq I, and Fok I polymorphisms on macrophage phagocytosis and lymphoproliferative response to mycobacterium tuberculosis antigen in pulmonary tuberculosis.

The regulatory role of vitamin D receptor (VDR) gene variants of Bsm I, Apa I, Taq I, and Fok I polymorphisms on vitamin D(3)-modulated macrophage phagocytosis with live Mycobacterium tuberculosis and lymphoproliferative response to M. tuberculosis culture filtrate antigen (CFA) was studied in patients with pulmonary tuberculosis (n = 46) and in normal healthy subjects (NHS) (n = 64). Vitamin D(3) at a concentration of 1 x 10(-7) M enhanced the phagocytic potential of normal subjects who had a phagocytic index of less than 20%. This increase was seen in subjects with the genotypes BB (p = 0.017), AA (p = 0.016), tt (p = 0.034), and FF (p = 0.013) and the extended genotype BBAAtt (p = 0.034). Normal subjects with BBAAtt performed better phagocytosis than individuals with bbaaTT genotype (p = 0.034). Vitamin D(3) at 10(-9), 10(-8), and 10(-7) M concentrations suppressed the lymphoproliferative response to CFA antigen in normal subjects. This decreased lymphocyte response was observed in normal individuals with the genotypes BB (p = 0.0009), tt (p = 0.016), and FF (p = 0.008) and the extended genotype BBAAtt (p = 0.02). Addition of vitamin D(3) had no significant effect on macrophage phagocytosis and lymphoproliferative response to CFA in pulmonary TB patients. This may be due to the unresponsive nature of the cells to the action of vitamin D(3) or the downregulated VDR expression by virtue of the disease, which renders them inactive. The genotypes BB, tt, and the extended genotype BBAAtt may be associated with increased expression of VDR which in turn regulate the action of vitamin D(3) and modulate the immune functions to M. tuberculosis in NHS.

Adult↗
PubMed2004

SCP1, a 356,023 bp linear plasmid adapted to the ecology and developmental biology of its host, Streptomyces coelicolor A3(2).

The sequencing of the entire genetic complement of Streptomyces coelicolor A3(2) has been completed with the determination of the 365,023 bp sequence of the linear plasmid SCP1. Remarkably, the functional distribution of SCP1 genes somewhat resembles that of the chromosome: predicted gene products/functions include ECF sigma factors, antibiotic biosynthesis, a gamma-butyrolactone signalling system, members of the actinomycete-specific Wbl class of regulatory proteins and 14 secreted proteins. Some of these genes are among the 18 that contain a TTA codon, making them targets for the developmentally important tRNA encoded by the bldA gene. RNA analysis and gene fusions showed that one of the TTA-containing genes is part of a large bldA-dependent operon, the gene products of which include three proteins isolated from the spore surface by detergent washing (SapC, D and E), and several probable metabolic enzymes. SCP1 shows much evidence of recombinational interactions with other replicons and transposable elements during its history. For example, it has two sets of partitioning genes (which may explain why an integrated copy of SCP1 partially suppressed the defective partitioning of a parAB-deleted chromosome during sporulation). SCP1 carries a cluster of probable transfer determinants and genes encoding likely DNA polymerase III subunits, but it lacks an obvious candidate gene for the terminal protein associated with its ends. This may be related to atypical features of its end sequences.

Amino Acid Sequence↗
PubMed2004

Molecular characterization of a strain of cucumber mosaic virus based on coat protein and movement protein genes.

Cucumber mosaic virus (CMV) A strain (CMV-A) isolated from Amaranthus tricolor was partially characterized at molecular level. Complete coat protein (CP) and movement protein (MP) ORFs were cloned and sequenced. The 657 bp region of CP gene and the 840 bp region of MP gene encode 218 and 276 amino acids, respectively. CP, at nucleotide level, showed 90-98% sequence identity with the CMV subgroup I and less than 80% with the CMV subgroup II, it showed at amino acid level 92-96% identity with the subgroup I and 74-87% with the subgroup II. The nucleotide and amino acid sequence identities of MP ranged in 91-94% and 92-96%, respectively with the subgroup I but in 81-83% with the subgroup II. Phylogenetic trees generated from nucleotide and amino acid sequences of both CP and MP genes identified the virus strain as a member of the subgroup IB. CMV-A CP also displayed a remarkably higher homology with Indian strains of CMV than with other CMV strains and formed a separate cluster within the subgroup IB.

Amino Acid Sequence↗
PubMed2004

Role of some factors on the breeding of JE vector Culex vishnui group.

Vector of JE, Culex vishnui group, prefer to breed in rice field. During the present study, roles of some factors like irrigation, manuring, pesticide application, rainfall, temperature and pH of the breeding water, depth of breeding water and height of paddy plants on breeding of Culex vishnui group larvae have been studied. It is evident from the study that besides striking role of the factors like manuring and pesticide application, other factors have also some role on the breeding of JE vectors at their breeding sites.

Agriculture↗
PubMed2003

Treatment of microfilaraemics with DEC and its effect on vector infection and infectivity in tribal and non-tribal areas of Bankura district, West Bengal, India.

Single course DEC treatment (6 mg/kg body weight/day for 12 days) was administered to 66 tribal and 442 non-tribal microfilaria (mf) carriers detected through a Filariasis survey in Bankura district, West Bengal, India. All the mf carriers remained amicrofilaraemic on 22nd, 180th and 365th post-treatment day. As a result of DEC treatment to the mf carriers, vector (Culex quinquefasciatus) infection rate in tribal study areas reduced from 2.06% to 1.07%. Infectivity rate was "nil" both before and after treatment. In non-tribal study areas, vector infection rate reduced from 4.33% to 2.22% and infectivity rate from 0.51% to 0.29%.

Animals↗
PubMed2002

Complete genome sequence of the model actinomycete Streptomyces coelicolor A3(2).

Streptomyces coelicolor is a representative of the group of soil-dwelling, filamentous bacteria responsible for producing most natural antibiotics used in human and veterinary medicine. Here we report the 8,667,507 base pair linear chromosome of this organism, containing the largest number of genes so far discovered in a bacterium. The 7,825 predicted genes include more than 20 clusters coding for known or predicted secondary metabolites. The genome contains an unprecedented proportion of regulatory genes, predominantly those likely to be involved in responses to external stimuli and stresses, and many duplicated gene sets that may represent 'tissue-specific' isoforms operating in different phases of colonial development, a unique situation for a bacterium. An ancient synteny was revealed between the central 'core' of the chromosome and the whole chromosome of pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae. The genome sequence will greatly increase our understanding of microbial life in the soil as well as aiding the generation of new drug candidates by genetic engineering.

Bacterial Proteins↗
PubMed2002

Primary and secondary metabolism, and post-translational protein modifications, as portrayed by proteomic analysis of Streptomyces coelicolor.

The newly sequenced genome of Streptomyces coelicolor is estimated to encode 7825 theoretical proteins. We have mapped approximately 10% of the theoretical proteome experimentally using two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. Products from 770 different genes were identified, and the types of proteins represented are discussed in terms of their annotated functional classes. An average of 1.2 proteins per gene was observed, indicating extensive post-translational regulation. Examples of modification by N-acetylation, adenylylation and proteolytic processing were characterized using mass spectrometry. Proteins from both primary and certain secondary metabolic pathways are strongly represented on the map, and a number of these enzymes were identified at more than one two-dimensional gel location. Post-translational modification mechanisms may therefore play a significant role in the regulation of these pathways. Unexpectedly, one of the enzymes for synthesis of the actinorhodin polyketide antibiotic appears to be located outside the cytoplasmic compartment, within the cell wall matrix. Of 20 gene clusters encoding enzymes characteristic of secondary metabolism, eight are represented on the proteome map, including three that specify the production of novel metabolites. This information will be valuable in the characterization of the new metabolites.

Acetylation↗
PubMed2000

Comparative epidemiological studies on lymphatic filariasis, between tribal and non-tribal populations of Bankura district, West Bengal, India.

There is little information on the epidemiology of lymphatic filariasis, caused by infection with Wuchereria bancrofti, in West Bengal. That which is known mostly relates to Calcutta and its suburbs, and there have been few studies on the disease among the tribal populations of the state. The present study was designed to compare the epidemiology of filariasis in tribal and non-tribal populations living in Bankura district. Blood samples were collected at night from 2076 tribal and 4985 non-tribal subjects and checked, microscopically, for microfilariae (mff). Each subject was also examined clinically, for any manifestations of the disease. The results revealed that the tribal subjects had not only lower prevalences of microfilaraemia (3.17% v. 8.86%) and of symptomatic filariasis (5.92% v. 13.74%) than the non-tribal, but also less intense infections (with mean counts for the microfilaraemics of 6.50 v. 13.55 mff/20 microliters blood). Filariasis endemicity, measured as the percentage of subjects with microfilaraemia and/or disease, was therefore much lower among the tribal subjects (8.95%) than the non-tribal (22.12%).

Adolescent↗
PubMed2000

Role of satellite RNA of an Indian isolate of cucumber mosaic virus in inducing lethal necrosis of tobacco plants.

Lethal necrosis or systemic stem necrosis followed by death of Nicotiana benthamiana, severe leaf deformations of N. tabacum cv. white burley and blister formations on N. tabacum cv. samsun NN symptoms were induced by experimental inoculations of CMV RNA preparations containing satellite RNA (sat-RNA). Inoculations of RNA preparations without sat-RNA did not induce that severe symptoms on these plants, only late mild mosaic was observed. It is suggested that sat-RNA of CMV isolate has a certain role for enhancing severity of symptoms in tobacco plants. Local and systemic lethal necrosis of N. benthamiana is due to sat-RNA present with genome of CMV isolate. It is the first report of lethal necrosis induced in N. benthamiana by CMV satellite.

Cucumber Mosaic Virus Satellite↗
PubMed1999

Bile acids: natural ligands for an orphan nuclear receptor.

Bile acids regulate the transcription of genes that control cholesterol homeostasis through molecular mechanisms that are poorly understood. Physiological concentrations of free and conjugated chenodeoxycholic acid, lithocholic acid, and deoxycholic acid activated the farnesoid X receptor (FXR; NR1H4), an orphan nuclear receptor. As ligands, these bile acids and their conjugates modulated interaction of FXR with a peptide derived from steroid receptor coactivator 1. These results provide evidence for a nuclear bile acid signaling pathway that may regulate cholesterol homeostasis.

Animals↗
PubMed1997

Some Indian strains of cucumber mosaic virus (CMV) lacking satellite RNA.

Virus strains isolated from Ocimum sanctum and Zinnia elegans were identified as cucumber mosaic virus (CMV) strains on the basis of non-persistant aphid transmission, 28 nm particles, 26 kDa coat protein subunits and serological relationships with CMV and chrysanthemum aspermy virus. The strains showed some biological, serological and satellite RNA based differentiation with other CMV strains isolated earlier from chrysanthemum, petunia and tobacco.

Cucumber Mosaic Virus Satellite↗