Search

Clerodendron inerme, a common hedge plant grown in India, is affected by a yellow mosaic disease caused by a begomovirus. In the present study, the complete genome (DNA A) of this virus was cloned and sequenced. The total size of DNA A is 2760 nucleotides. The genome of this virus contains six open reading frames and a non-coding intergenic region of 293 nucleotides. Nucleotide sequence comparison analysis revealed maximum sequence identity with Papaya leaf curl virus-Pakistan [Pakistan:Cotton:2002] (73.9%). As this virus had less than 89% identity with other begomoviruses, it was identified as a new begomovirus species and tentatively, named as Clerodendron yellow mosaic virus-[India:New Delhi:2007] (ClYMV-[IN:ND:07]).

A relatively inexpensive protocol for the detection of genomic components of whitefly-transmitted begomoviruses in symptomatic legumes in the field is described. The method involves extraction with a modified CTAB buffer containing beta-mercaptoethanol upto 5% and sodium chloride concentration from 1.4 to 2.0M. Using this method PCR amplifiable DNA could be extracted from mature leaves of legume hosts rich in polyphenols, tannins and polysaccharides. The non-coding region and full-length DNA A, DNA B components of yellow mosaic viruses were consistently amplifiable from 97 samples, out of 136 tested in PCR reaction, employing primers specific for intergenic regions and full-length genome. The system is robust and the protocol is useful for the detection and identification of begomoviruses infecting grain legumes.

The AV promoter expressing AV1 and AV2 genes and AC1 promoter expressing AC1 gene are present in opposite orientation in the intergenic region of Mungbean yellow mosaic India virus (MYMIV). Transient Agrobacterium-mediated delivery of putative promoter constructs into Nicotiana benthamiana and different legumes, followed by reporter gene (beta-d-glucuronidase, GUS) assay, identified the promoter region of both AC1 and AV genes that is necessary for transcriptional initiation. Transcription activator protein-independent activity of AV promoter and differential regulation of AC1 promoter are unique to MYMIV. The AV promoter is a composite core promoter having both TATA box and Initiator elements (TATA(+)Inr(+)). Many transcription factor binding sites were identified in the upstream promoter sequences of both virion and complementary sense genes, which might be used in the transcription regulation studies of the host plant as well as the virus.

Rice tungro, economically the most important viral disease of rice, is a complex disease caused by two morphologically and genomically dissimilar viruses, Rice tungro bacilliform virus (RTBV), a double stranded DNA virus replicating through RNA intermediate and Rice tungro spherical virus (RTSV), a single stranded RNA virus with 3' poly (A) tail. A novel multiplex RT-PCR technique for the simultaneous detection of RTBV and RTSV from the total RNA extracted from tungro-infected plants has been developed. It involves a one-step reaction initiating first strand cDNA synthesis by oligo (dT) primer with poly (A) tailed RTBV transcript and RTSV genomic RNA as template for the PCR amplification. The results indicate that adaptation of this technique will strengthen the screening for tungro resistance among rice varieties and hybrids.

The specific activity of cyclic adenosine 3':5'-monophosphate phosphodiesterase was measured in lymphocytes isolated from the blood of normal subjects, from patients with chronic lymphocytic leukemia, and from tonsil tissue. The mean specific activity of cyclic adenosine 3':5'-monophosphate phosphodiesterase in the lymphocytes from patients with untreated chronic lymphocytic leukemia was lower than that in lymphocytes from the blood of normal subjects or from tonsils. Cyclic adenosine 3':5'-monophosphate phosphodiesterase levels did not correlate with differences in B- and T-cell lymphocyte subpopulations or with peripheral blood lymphocyte counts.

Inactive, frozen and thawed cytoplasmic extracts of 3T3 and SV-101 (3T3 transformed by SV-40 virus) cells contain an inhibitor which blocks the poly(U)-directed incorporation of [14C]phenylalanine into polypeptides, catalyzed by active extracts of these cells. This inhibition is not reversed by adding increased amounts of poly(U). Furthermore, little or no inhibitory activity is observed when poly(U) translation is assayed using precharged [14C]Phe-tRNA. These results suggest that the observed inhibition is not due to the degradation of poly(U) by a nuclease. The inhibitor appears to act primarily at the level of tRNA charging since the synthesis of both Phe-tRNA and Lys-tRNA is impaired in its presence. Evidence is presented which indicates that the inhibitory activity is not due to a high molecular weight protein or nucleic acid. However, the inhibitor appears to be adsorbed to a macromolecule. The inhibitory activity is completely destroyed by ashing.

1. The biosynthesis of nucleic acid purine in Mycobacterium tuberculosis H(37)R(v) has been studied by using (14)C-labelled precursors. 2. The results indicate that C-2 and C-8 of the purine ring are derived most efficiently from serine and glycine and not from formate. 3. [(14)C]Methionine is not incorporated into the ureide carbon atoms of the purine ring.