PubMed Health⌕ Search

Biomedical subjects

M Geetha

Publications and source records attributed to M Geetha.

7 recordsLinked to original sources
PubMed2007

Normal human plasma anti-beta-glucoside antibody has markedly elevated IgA content and binds fungal and yeast polysaccharides.

Normal human plasma antibody that recognizes beta-linked glucoside moiety was purified by affinity chromatography on cellulose. The anti-beta-glucoside antibody had three times higher IgA to IgG ratio and substantially higher polymeric IgA content than total serum immunoglobulins. Cellobiose and other beta-glucosides were best inhibitors of its binding to polystyrene microwell-coated polysaccharides. In synthetic glycoproteins made by conjugating disaccharides to hemoglobin or bovine serum albumin, cellobiose, unlike lactose or maltose, was sugar-specifically recognized by the antibody. It also recognized polystyrene well-coated beta1-->3 linked glycans of Saccharomyces cerevisiae, Candida albicans and of barley in decreasing order of affinity. Its sugar-binding site could thus accommodate beta-glucoside with or without substitution at C4 and C3. High IgA content along with the capacity to bind common microbial and dietary antigens pointed to the immune inflammatory potential of the antibody.

Antibodies↗
PubMed2006

Evaluation of ELISA based on the conserved and functional middle region of nucleocapsid protein to detect distemper infection in dogs.

A 287bp fragment from the middle region of the nucleocapsid protein of canine distemper virus (CDV) was amplified from the conjunctival samples of distemper-infected dogs and was cloned into pRSET B vector. The recombinant protein was expressed as a 16-kDa-fusion protein with histidine tag in E. coli. Sera of distemper-infected and vaccinated dogs contained IgG antibodies against the purified recombinant protein as observed by enzyme linked immunosorbent assays (ELISA) and showed a strong correlation (r=0.882, p<0.0001 at 95% CI) and good agreement (kappa=0.718) with the conventional tissue culture viral antigen based ELISA. Further, the results of recombinant protein based ELISA and Western blotting with the sera from the infected and vaccinated dogs correlated well (kappa=0.8226). These findings recommend the use of the recombinant protein in the serodiagnosis of canine distemper virus infection in dogs.

Animals↗
PubMed2002

Molecular characterization of a calcium binding translationally controlled tumor protein homologue from the filarial parasites Brugia malayi and Wuchereria bancrofti.

We have cloned homologues of the mammalian translationally controlled tumor protein (TCTP) from the human filarial parasites Wuchereria bancrofti and Brugia malayi. TCTP genes from B. malayi and W. bancrofti were expressed in a T7 promoter vector as histidine tagged fusion proteins. Both the recombinant B. malayi TCTP (rBm-TCTP) and recombinant W. bancrofti TCTP (rWb-TCTP) have a molecular mass of approximately 28 kDa with the histidine tag. Sequence analyses showed that there is a 98% similarity between the two filarial TCTPs at amino acid levels and are immunologically cross-reactive. Analysis of soluble proteins from various lifecycle stages of B. malayi suggested that the expression of Bm-TCTP might be differentially regulated and occurs in multimeric form. Recombinant TCTP were found to form multimers in solution under non-reducing conditions. The tendency for filarial TCTPs to become multimers was predicted by the presence of the Lupas coiled coil structure in their sequence. Despite the absence of a signal sequence, Bm-TCTP is present abundantly in the excretory/secretions (ES) of microfilariae. Characterization studies showed that both Bm- and Wb-TCTPs are calcium-binding proteins and have histamine-releasing function in vitro. When injected intraperitoneally both the filarial TCTPs induced inflammatory infiltration of eosinophils into the peritoneal cavity of mice suggesting that the filarial TCTPs may have a role in the allergic inflammatory responses associated with filarial infections.

Amino Acid Sequence↗
PubMed2001

Studies on characterisation and thermal behaviour of 3-amino-5-nitro-1,2,4-triazole and its derivatives.

3-Amino-5-nitro-1,2,4-triazole (ANTA) and its derivatives have been prepared in order to carry out the systematic studies on structural aspects, explosive and thermal behaviour. Thermal studies were carried out for ANTA and 4,6-bis-(3-amino-5-nitro-1H-1,2,4-triazole-1-yl)-5-nitropyrimidine (DANTNP) by thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimeter (DSC) and manometric thermal analysis. The results show that (DANTNP) is more thermally stable than ANTA when compared in terms of activation energy.

Explosions↗
PubMed2000

Glutaraldehyde cross-linking of lectins to marker enzymes: protection of binding site by specific sugars.

The role of bound specific sugars in protecting the sugar binding activity of several galactose binding proteins during their covalent conjugation to horse radish peroxidase by glutaraldehyde-mediated cross-linking was examined by: a) affinity matrix binding of the conjugate, b) enzyme linked lectin assay and c) hemagglutination assay. During conjugation using 1% glutaraldehyde, protection of jack fruit (Artocarpus integrifolia) lectin (jacalin) activity depended on concentration of specific sugar present during conjugation; optimum protection was offered by 50 mM galactose. This indicated the presence of one or more primary groups at the binding site of jacalin, which is (are) essential for sugar binding. On the other hand, such essential amino group(s) was not indicated at the sugar binding site of the peanut lectin, bovine heart galectin or of the human serum anti alpha-galactoside antibody, since exclusion of sugar during their conjugation to HRP did not diminish sugar binding activity. The differential behavior is discussed in the light of reported differences in sugar specificities. Results indicated that sugar mediated blocking of active site may be used in characterization of the latter in lectins.

Animals↗
PubMedDate not supplied

Wuchereria bancrofti: cloning and characterization of heat shock protein 70 from the human lymphatic filarial parasite.

Heat shock protein 70 (HSP70) was identified as an immunodominant antigen by screening a Wuchereria bancrofti (Wb) microfilarial cDNA library with pooled Wb-infected sera, with 28% of the immunopositive clones coding for Wb-HSP70. The deduced amino acid sequence showed greater than 97 and 85% identity with HSP70 from filarial nematodes and humans, respectively. Recombinant HSP70 (74 kDa) and a recombinant protein from the C-terminal portion (43 kDa) also reacted with pooled Wb-infected sera, suggesting that the C-terminal region of HSP70 contains at least one antibody epitope. Brugia malayi L3 larvae showed increasing levels of HSP70 with increasing temperatures. Further, a polyclonal mouse anti-Wb-HSP70 antibody had reactivity to the HSP70 of cattle filarial parasite Settaria digitata and to human HSP70 derived from a Hep-2 cell line. Immune reactivity to Wb-HSP70 was strong, with uninfected non-endemic normal sera showing significantly greater reactions than sera from filaria-infected individuals. Both immunodominant self-HSP70 and HSP70 from other microbial infections may be primary targets for developing autoantibodies naturally.

Amino Acid Sequence↗