NISCAIR Online Periodicals Repository Community: IJBB Vol.42 [2005]

Expression of Δ¹-pyrroline-5-carboxylate synthetase gene during drought in rice (Oryza sativa L.)

Mon, 28 Nov 2005 22:58:59 GMT

Title: Expression of Δ¹-pyrroline-5-carboxylate synthetase gene during drought in rice (Oryza sativa L.)

Authors: Choudhary, N L; Sairam, R K; Tyagi, A

Abstract: The 45-days-old seedlings of drought resistant (N-22, CR143-2-2) and susceptible rice (Oryza sativa L.) genotypes (Panidhan, Pusa-169) were subjected to osmotic stress in PEG-6000 solution of -10 and -16 bar and the relative water content (RWC), proline content, and pyrroline-5-carboxylate synthetase (P5CS) activity and its P5CS expression were studied. A gradual decrease in RWC was observed in tolerant genotypes, whereas the decrease was drastic in susceptible ones. Proline content and P5CS activity increased both in susceptible and tolerant genotypes; the increase was higher in tolerant genotypes. Higher proline levels in tolerant genotypes were due to increased P5CS activity. The EcoRI, BamHI and XbaI restricted DNA of N-22 and Panidhan genotypes were hybridized with Arabidopsis P5CS sequence and a single band (approx 2.4 kb) was observed, however, P5CS expression was more in N-22, as compared to Panidhan.

Page(s): 366-370

Production of human single-chain variable fragment (scFv) antibody specific for digoxin by ribosome display

Mon, 28 Nov 2005 22:58:59 GMT

Title: Production of human single-chain variable fragment (scFv) antibody specific for digoxin by ribosome display

Authors: Yan, Xiang-Hua; Xu, Zi-Rong

Abstract: Ribosome display was applied in vitro to select single-chain variable fragment (scFv) antibody specific for digoxin from a human non-immune naive scFv library. A cell-free system was used to produce stable antibody-ribosome-mRNA (ARM) complexes to provide the linkage of genotype and phenotype, allowing simultaneous selection of a desired antibody together with its encoding mRNA. The mRNA was then recovered and amplified as DNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Repeating the display cycle enriched the selected molecules, enabling rare species to be isolated. In this study, digoxin-binding segments were selected over four cycles of ARM display and the selected DNA was cloned and expressed as a single-chain variable fragment antibody (the best scFv, A3) in Escherichia coli. The affinity (equilibrium dissociation constant Kd) of digoxin was 8.3 × 10⁻⁸ M for A3, which validated construction of the naïve library and the power of ribosome display lending to the evolution of functional characteristics, such as potency of leading candidate antibodies to provide therapeutic antibodies. A3 was purified using affinity chromatography and determined by Western blot. The results indicate that ribosome display technnique can be efficiently used to isolate specific antibody fragments from a naive library.

Page(s): 350-357

Lead levels in some biological samples of auto-mechanics in Abeokuta, Nigeria

Mon, 28 Nov 2005 22:58:59 GMT

Title: Lead levels in some biological samples of auto-mechanics in Abeokuta, Nigeria

Authors: Babalola, O O; Ojo, L O; Aderemi, M O

Abstract: Lead levels were determined in the blood, scalp hair and fingernails of 38, all male auto-mechanics (aged 18-45 years) from Abeokuta, South-western Nigeria. The subjects were classified into four sub-groups based on the period of exposure namely: 1-5, 6-10, 11–15, and >16 years. Thirty-two occupationally unexposed subjects (mainly office workers) served as the control. The weight, height and body mass indexes of all subjects were noted, in addition to other information obtained through structured questionnaire. The mean values of blood lead (BPb), hair lead (HPb) and fingernail lead (NPb) of the occupationally exposed subjects (n=38) were 48.50 ± 9.08 μg/dL, 17.75 ± 5.16 μg/g, and 5.92 ± 3.30 μg/g respectively, while the corresponding mean values for these parameters in the control subjects (n = 32) were 33.65 ± 10.09 μg/dL, 14.30 ± 5.90 g/g and 5.31 ± 2.77 μg/g respectively. The differences in BPb and HPb levels of the two groups were statistically significant (P <0.05 and P <0.01 respectively), while that of NPb was not significant. The levels of lead in the biological samples appeared to have no relationship with the number of years on the job. From these results, it was obvious that the higher levels of lead in the biological samples of test subjects, compared with those of the controls were from environmental sources.

Page(s): 401-403

Antibacterial activity of some unsymmetrical diorganyltellurium(IV) dichlorides

Mon, 28 Nov 2005 22:58:59 GMT

Title: Antibacterial activity of some unsymmetrical diorganyltellurium(IV) dichlorides

Authors: Soni, Daya; Gupta, Prabhat K; Kumar, Yatindra; Chandrashekhar, T G

Abstract: Six unsymmetrical diorganyltellurium(IV) dichlorides RR'TeCl₂ (where R= phenacyl-, 1-naphthacyl-, and styrylacyl- and R' = p-methoxyphenyl, p-hydroxyphenyl-, and 3-methyl-4-hydoxyphenyl-) were tested for their antibacterial activity against gram-positive (Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923) and gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Salmonella sp.) bacteria. Antibacterial activity was measured by disk diffu-sion method. Inhibition zones demonstrated that all the compounds showed good activity against gram-negative strains. Phenacyl (3-methyl-4-hydroxyphenyl) tellurium(IV) dichloride and naphthacyl (3-methyl-4-hydroxyphenyl) tellurium(IV) dichlo-ride showed significant activity against both gram-positive and gram-negative strains. Among the tested compounds, the former exhibited maximum activity against gram-positive bacteria, while the latter against all the bacteria under study and styrylacyl (p-methoxyphenyl) tellurium(IV) dichloride against all the three gram-negative bacteria.

Page(s): 398-400