NISCAIR Online Periodicals Repository Collection: IJBT Vol.04(4) [October 2005]

Concurrent infection with WSSV and MBV in Tiger prawn, Penaeus monodon (Fabricious) in West Bengal and their detection using PCR and DNA Dot-blot hybridization technique

Wed, 28 Sep 2005 22:58:59 GMT

Title: Concurrent infection with WSSV and MBV in Tiger prawn, Penaeus monodon (Fabricious) in West Bengal and their detection using PCR and DNA Dot-blot hybridization technique

Authors: Mishra, S S; Shekhar, M S; Azad, I S

Abstract: Prevalence status of white spot disease (WSD), caused by white spot syndrome virus (WSSV) and Monodon baculovirus (MBV), was studied in different prawn farms in North and South-24 paragana districts of West Bengal, specifically in the areas previously affected by WSD. In total 283 samples of giant tiger prawn Penaeus monodon, Indian white prawn P. indicus and giant freshwater prawn Macrobrachium rosenbergii from 12 different farms were screened and presence of MBV occlusion-bodies (Obs) were detected. Of samples screened, 30 samples showed multiple spherical Obs typical of MBV infection. Of 80 samples screened using PCR, 17 (21.25%) were positive for MBV and 51 samples (63.75%) were positive for WSSV, and amplified DNA of 674 bp and 643 bp, respectively was visualized on 1% agarose gel electrophoresis. Significantly all samples showing positive reaction with MBV were also positive for WSSV in PCR, indicating co-infection of prawns with both MBV and WSSV. However, none of the M. rosenbergii samples were positive of MBV-Obs but 5 samples were positive for WSSV in PCR. Both MBV and WSSV amplified DNA were labeled with alkaline phosphatase using Alkphos DNA labeling reagent kit and samples were screened using DNA dot-blot and slot-blot hybridization. All samples showing positive PCR reaction were also found positive in DNA hybridization

Page(s): 506-515

In vitro micropropagation of Geoderum purpureum R.Br

Wed, 28 Sep 2005 22:58:59 GMT

Title: In vitro micropropagation of Geoderum purpureum R.Br

Authors: Mohapatra, A; Rout, G R

Abstract: An in vitro micropropagation system was developed for Geoderum purpureum, an important terrestrial orchid, through axillary meristem culture and by manipulating cytokinin and auxin. Multiple shoots were induced from explants cultured on agar-based Murashige and Skoog medium supplemented with 6-benzylaminopurine (BAP; 2.0-3.0 mg/L), indole-3-acetic acid (IAA; 0.5-1.0 mg/L) and sucrose [3% (w/v)]. Maximum number of shoot buds was obtained with 3.0 mg/L BAP and 1.0 mg/L IAA. The rate of shoot multiplication was maintained in subsequent subculture on similar fresh culture medium. Elongated shoots were separated and rooted on half strength basal MS medium supplemented with IAA or IBA and 2% (w/v) sucrose. Maximum percentage of rooting was obtained on medium having 0.5 mg/L IAA. Plantlets, thus developed were established in soil with 80% surviability.

Page(s): 568-570

Batch kinetic studies in phenol biodegradation and comparison

Wed, 28 Sep 2005 22:58:59 GMT

Title: Batch kinetic studies in phenol biodegradation and comparison

Authors: Vijayagopal, V; Viruthagiri, T

Abstract: Pure cultures of pseudomonas putida, Nocardia sp., Bacillus circulans and a mixed culture, isolated from mangrove forest soil, were used to study phenol biodegradation in the batch reactor. The aim was to determine the kinetics of phenol biodegradation by measuring the biomass growth rates and phenol concentration as a function of time in a batch reactor. The kinetic constants, specific growth rate ( _m), inhibition coefficient for phenol (K_i) and half saturation coefficient for phenol (K_s) were determined using the Haldene equation [ _ms/(K_s + S + (S²/K_i)]. The values obtained for kinetic constants are in the range of those published in literature for pure and mixed cultures degrading phenol. The length of the lag phase before the exponential growth phase increases linearly with phenol concentration. As compared to others, p. putida has the maximum specific growth rate both in the present study as well as in literature. Thus, selecting a pure culture of p. putida for phenol degradation could lead to higher efficiencies.

Page(s): 565-567

Influence of fermentation conditions on levan production by Zymomonas mobilis CT2

Wed, 28 Sep 2005 22:58:59 GMT

Title: Influence of fermentation conditions on levan production by Zymomonas mobilis CT2

Authors: Senthilkumar, V; Gunasekaran, P

Abstract: Zymomonas mobilis produces two extracellular sucrases namely levansucrase (sac B) and sucrase (sac C). A mutant strain of Z. mobilis CT2 defective in sucrase sac C, constructed earlier by gene disruption¹, produced higher levels of levan (27.2 g L^-1) than the parent strain B14023 (15.4 g L^-1) from 200 g L^-1 of sucrose at 25°C and pH 5.0. Increasing fermentation temperature from 25 to 35°C enhanced ethanol concentration from 17.8 to 46.4 g L^-1 due to increased rate of sucrose hydrolysis but decreased the transfructosylation activity from 165 to 56 U mL^-1. Addition of glucose or fructose to the fermentation medium considerably reduced the levan production due to the inhibition of levansucrase activity.

Page(s): 491-496