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Biomedical subjects

A K Tewari

Publications and source records attributed to A K Tewari.

6 recordsLinked to original sources
PubMed2004

Role of antibiosis in the biological control of spot blotch (Cochliobolus sativus) of wheat by Chaetomium globosum.

Chaetomium globosum Kunze, has been identified as a potential antagonist of Cochliobolus sativus (S. Ito & Kurib.) Deschler ex Dastur. (Syn = Drechslera sorokiniana). Production of antifungal compounds by Chaetomium globosum (Cg) and their role in suppression of spot blotch of wheat caused by this fungus under in vitro and in vivo has been evaluated. Interaction between Chaetomium globosum isolates and C. sativus showed mycoparasitism by isolates Cg 1 and Cg 6 whereas isolates Cg 2, Cg 3, Cg 4 and Cg 5 showed antibiosis. Syringe filtered culture extracts of Cg 2 completely inhibited mycelial growth of C. sativus in liquid broth. In vitro bioassays were undertaken by amending the medium with crude extracts and agar diffusion method in order to assess the fungistatic activity of crude extracts from culture filtrates of different isolates of Chaetomium globosum. Significant differences in antagonism between isolates were observed. Antifungal metabolite profiling, on TLC (Thin Layer Chromatography) plates identified 13 compounds in isolate Cg 2, 11 compounds in Cg 3 and 7 compounds in Cg 6. Isolate Cg 1 produced only two faint bands and Cg 5 produced two bands of the same Rf value but of higher intensity. The production of antifungal compounds by isolates was positively correlated with antagonism to C. sativus on seedlings in glasshouse studies. The results showed high antifungal metabolite production by isolate Cg 2, which also gave maximum bioefficacy under laboratory and glasshouse conditions.

Antifungal Agents↗
PubMed2001

Synthesis and anti-inflammatory activities of N4,N5-disubstituted-3-methyl- H-pyrazolo[3,4-c]pyridazines.

The synthesis and anti-inflammatory activity of 4,5-dihydroxy-3-methyl-1H-pyrazolo[3,4-c]pyridazine (4), 4,5-dichloro-3-methyl-1H-pyrazolo[3,4-c]pyridazine (5), 4,-benzoyloxy-3-methyl-1-benzoyl-1H-pyrazolo[3,4-c]pyridazin-5yl benzoate (6), 3-methyl-N4,N5-bis(4-methylphenyl)-1H-pyrazolo[3,4-c]pyridazine-4,5-diamine (7), 4[[5-(4-carboxyanilino)-3-methyl-1H-pyrazolo[3,4-c]pyridazin-4yl]amino]benzoic acid (8), N-[5-(benzoylamino)-3-methyl-1H-pyrazolo[3,4-c]pyridazin-4-yl]benzamide (9) and 3-methyl-N4,N5-bis[4-(1H-benzimidazol-2yl)phenyl]-1H-pyrazolo[3,4-c]pyridazine-4,5-diamine (10) are being reported.

Animals↗
PubMed1997

Comparison of indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) in detecting Babesia bigemina infection in cattle.

An indirect immunofluorescence test (IIF) and an enzyme-linked immuno-sorbent assay (ELISA) were standardised to investigate the prevalence of bovine babesiosis caused by Babesia bigemina in experimentally and naturally infected bovids. Both IIF and ELISA detected antibodies to B. bigemina 7 days after experimental infection with 87.5% and 100% sensitivity, respectively. The IIF results indicated that a titre greater than 1:64 was a reliable indicator of B. bigemina infection. Serological study of 214 serum samples collected from Boophilus microplus infested cattle from the State of Orissa revealed 33.6% overall seroreactivity by ELISA, whereas IIF recorded 9.4%. Both IIF and ELISA showed some degree of cross-reactivity between Indian (Izatnagar) and Mexican strains of B. bigemina.

Animals↗
PubMed1996

Effect of Mycobacterium phlei on the development of immunity to Babesia bigemina.

The immunomodulatory role of Mycobacterium phlei against intracellular blood protozoan Babesia bigemina was demonstrated following experimental immunisation and challenge in bovine calves. A lysate of erythrocytes infected (6 x 10(9)) with B. bigemina was used as a source of dead antigen either with Freund's complete adjuvant (FCA) or with a trypsinised culture of M. phlei as a non-specific immunomodulation (NSI) agent with appropriate controls. Following virulent challenge with B. bigemina infected erythrocytes (1 x 10(7)), the NSI printed calves showed 100% protection, while the dead antigen alone with FCA afforded 75% protection. The protective status of the immunising regimes was studied by clinicopathological parameters and assessment of humoral and cell-mediated immune responses. The role of babesial dead antigen and the effects of M. phlei on the development of immunity to B. bigemina is discussed.

Animals↗