NISCAIR Online Periodicals Repository Collection: IJBB Vol.46(3) [June 2009]

Antioxidant status in polycystic end-staged renal diseased patients and antihemolytic effect of Boerhaavia diffusa

Title: Antioxidant status in polycystic end-staged renal diseased patients and antihemolytic effect of Boerhaavia diffusa

Authors: Sathyapriya, K; Vijayachandrika, V; Parameswari, C S

Abstract: Chronic renal failure (CRF) induces anaemia by shortening the life-span of erythrocytes, due to an increase in oxidative stress, which is considered to be one of the major risk factors in CRF patients undergoing hemodialysis. In the present study, the antioxidant status of the end-staged renal disease (ESRD) patients was investigated. The antihemolytic activity of Boerhaavia diffusa on the erythrocytes of the patients was also studied. Protein, lipid peroxides (LPO), reduced glutathione (GSH) levels and glutathione peroxidase (GPX) and glutathione-S-transferase (GST) activities were measured in the hemolysate from 55 polycystic ESRD patients (Group II) and compared with normal subjects (Group I). The antioxidant status was found to be significantly reduced in the patients as compared to normal healthy volunteers, due to increased oxidative stress. Also, aqueous extract of B. diffusa showed a significant antihemolytic activity on the erythrocytes of the polycystic ESRD patients.

Page(s): 269-272

Single-stranded megaprimer splicing through OE-PCR: Construction of full-length Aspergillus niger arginase cDNA

Title: Single-stranded megaprimer splicing through OE-PCR: Construction of full-length Aspergillus niger arginase cDNA

Authors: Jayashri, T N; Anuradha, R; Punekar, N S

Abstract: A useful variant of PCR technique was devised to generate full-length Aspergillus niger arginase cDNA for expression. Briefly, a 450 bp amplicon was first constructed through overlap extension PCR (OE-PCR) by splicing in a 101 nucleotide long single-stranded megaprimer, facilitated by inclusion of an additional, shorter forward primer in the reaction. The amplicon was suitably cloned into pBlueScript to obtain pArg440 and the insert sequenced. The full-length arginase cDNA was subsequently assembled in pArg440 and moved into pET23a for heterologous expression. An interesting feature of this strategy was not to stoichiometrically incorporate the oligonucleotide megaprimer, but use it only as an early template. This OE-PCR strategy to utilize long single-stranded megaprimer may prove handy in terms of efficiency, yield and sequence choice.

Page(s): 266-268

Buffering capacity and membrane H⁺ conductance of protease producing facultative alkaliphilic bacterium Bacillus flexus from mangrove soil

Title: Buffering capacity and membrane H⁺ conductance of protease producing facultative alkaliphilic bacterium Bacillus flexus from mangrove soil

Authors: Kannan, P; Ignacimuthu, S; Paulraj, M Gabriel

Abstract: A facultative alkaliphilic protease-producing gram-positive rod-shaped bacteria (EMGA 5) was isolated from mangrove soil and confirmed as Bacillus flexus by the 16S rDNA sequence. Buffering capacity and membrane H⁺ conductance of this alkaliphilic isolate were investigated for the cells grown at pH 7.2 and 10.5 using acid pulse technique. Suspensions of B. flexus cells grown in poly peptone yeast glucose medium at pH 10.5 exhibited higher cytoplasmic membrane buffering capacity values (70 µmol H⁺/pH unit/mg protein at pH 9.9) than the cells grown at pH 7.2 (41 µmol H⁺/pH unit/mg protein at pH 9.9). B. flexus grown aerobically at pH 7.2 showed higher H⁺ conductance values than the cells grown at pH 10.5 (0.032 µmol H⁺/s/pH unit/mg protein at pH 9.9 and 0.028 µmol H⁺/s/pH unit/mg protein at pH 9.8, respectively). The present study revealed that the buffering capacity and membrane H⁺ conductance of the B. flexus isolates were influenced by pH of the medium.

Page(s): 261-265

Photoinhibition and photosynthetic acclimation of rice (Oryza sativa L. cv Jyothi) plants grown under different light intensities and photoinhibited under field conditions

Title: Photoinhibition and photosynthetic acclimation of rice (Oryza sativa L. cv Jyothi) plants grown under different light intensities and photoinhibited under field conditions

Authors: Vaz, Janet; Sharma, Prabhat Kumar

Abstract: Thirty-days old rice (Oryza sativa L. cv. Jyothi) plants grown under the greenhouse (150-200 µmol m^-2 s^-1) or shade (600-800 µmol m^-2s^-1) were exposed to 7 days of full sunlight and compared with plants grown under direct sunlight (1200-2200 µmol m^-2s^-1).Transfer of greenhouse and shade plants to full sunlight for a day resulted in a decline in their photosynthetic efficiency (F_v/F_m) and an increase in non-photochemical quenching (qN). The decline in F_v/F_m was much greater in transferred greenhouse plants (33%) as compared to transferred shade-plants (20%). Sun-plants did not show much variation in the F_v/F_m ratio (4%) from their predawn measurements (control). The sun-grown plants showed a higher pool of xanthophyll pigments (violaxanthin + antheraxanthin + zeaxanthin). Transfer of greenhouse and shade-plants to full sunlight resulted in an increase in lutein, Chl a/b ratio, antheraxanthin (A) and zeaxanthin (Z) content. Increase in A and Z was correlated with the increase in the qN. The increase in the A and Z content was due to increase in the activity of violaxanthin de-epoxidase. Greenhouse and shade plants on exposure to sunlight showed an increase in lipid peroxidation (LPO). Prolonged exposure of greenhouse and shade plants up to 7 days resulted in recovery of the F_v/F_m, an increase in Z and A and a decline in the LPO. The study demonstrated that rice plants grown at lower light intensities initially underwent photoinhibitory damage on exposure to full sunlight, but were able to acclimate to the high irradiance by dissipating the excess light through various mechanisms such as an increase in lutein, high Chl a/b ratio and xanthophyll cycle, suggesting use of energy dissipation as a mechanism of protection against high irradiance, but to different extent and to some extent by different processes. The study was unique, as plants were grown and photoinhibited under natural conditions rather than the artificial light, as was the case in most of the studies so far. Results showed better adaptation of high-light grown plants and suggested role for chl a/b ratio and lutein, in addition to xanthophylls cycle in shade plants. Low-light grown plants could also completely adapt to full level of sunlight within 3 days of the treatment and xanthophylls cycle (measured as V, A and Z) and activity of de-epoxidase seemed to be important in this adaptation.

Page(s): 253-260

NISCAIR Online Periodicals Repository Collection: IJBB Vol.46(3) [June 2009]

Antioxidant status in polycystic end-staged renal diseased patients and antihemolytic effect of Boerhaavia diffusa

Single-stranded megaprimer splicing through OE-PCR: Construction of full-length Aspergillus niger arginase cDNA

Buffering capacity and membrane H+ conductance of protease producing facultative alkaliphilic bacterium Bacillus flexus from mangrove soil

Photoinhibition and photosynthetic acclimation of rice (Oryza sativa L. cv Jyothi) plants grown under different light intensities and photoinhibited under field conditions

Buffering capacity and membrane H⁺ conductance of protease producing facultative alkaliphilic bacterium Bacillus flexus from mangrove soil