Dot blot hybridization assay for the detection of duck hepatitis B virus DNA among healthy Indian country ducks.

A DNA molecular hybridization technique employing Duck Hepatitis B Virus (DHBV) DNA of 3.0 kilobase pairs as a probe was used to screen for the presence of DHBV DNA in blood samples, collected from 90 apparently healthy Indian country ducks. Six out of 90 ducks showed positivity for DHBV DNA in serum (5.4%) and only 4 out of 6 DHBV DNA positive ducks answered in Counter Immuno Electrophoresis (CIEP) using specific antibody against DHBV surface antigen raised in Guinea pig. The results indicate the pilot observation that (a) DHBV carrier status exists to a tune of 5.4% among apparently healthy Indian country ducks also and (b) DHBV probe can be employed as a sensitive and reliable assay for DHBV DNA detection in DHBV infected ducks.

Synthesis of ribulose 1,5—bisphosphate carboxylase by isolated Sorghum mesophyll chloroplasts.

Chloroplasts isolated from Sorghum vulgare are active in light-dependent, organelle protein synthesis. Intact chloroplasts can use light as an energy source; photosynthetically inactive chloroplasts require the addition of ATP for this protein synthesis. P reincubation of chloroplasts in light at 25°C for 1 h depleted the endogenous templates completely; such preincubated chloroplasts translated exogenously added heterologous templates efficiently. When total cellular RNA from Chlorella protothecoides, a C3 plant, was used as template for translation in a cell-free light-dependent system of isolated mesophyll chloroplasts from Sorghum vulgare, a C4 type plant, polypeptides of 55 kDa (large subunit) and 15 kDa (small subunit) were detectable in the fluorographic profile of the newly synthesized proteins; these polypeptides were absent in the products obtained with endogenous RNA. Evidence for the fidelity of the system was obtained by immunological arenlallay sis of ribulose 1, 5-bisphosphate carboxylase obtained by the translation of Chlo Acesl.l ular RNAs.

Heat shock response of Chlorella protothecoides during greening.

Heterotrophically grown cells of Chlorella protothecoides were transferred to autotrophic medium and allowed to green at 25°C. The protein synthetic activity of the greening cells measured in terms of incorporation of [35S]-methionine showed a maximum around 20 h of greening and thereafter started declining. Similarly, an analysis of densitometric tracings of the fluorographic profile of the polypeptides associated with both total cellular fraction and membrane fractions during different hours of greening revealed that maximum number of polypeptides were getting labelled around 20 h of greening. At 20 h of greening, the cells were shifted to 40°C and the effect of heat shock on protein synthesis was studied. The heat shock treatment caused a definite decrease in the incorporation of [35S]- methionine into proteins. Due to heat shock, the synthesis of total soluble proteins was affected much more than that of the thylakoid membrane bound proteins. When the cells were transferred back to 25°C after a brief period of heat shock at 40°C, there was a considerable recovery in the protein synthesis and this recovery was found to be significant in the case of soluble proteins, while there was no such definite recovery in the synthesis of thylakoid membrane bound proteins.