Biomedical subjects

D G Harnish

Publications and source records attributed to D G Harnish.

22 records · Page 2Linked to original sources

PubMed1982

An evolutionary model for the insect vitellins.

Insects can be divided into three groups based on the sizes of the polypeptide constituents of their vitellogenins and vitellins. In order to determine the relationships between these groups, antisera to the vitellins of seven insects from six taxonomic orders were used to assess immunological cross-reactivity. Antigenic relatedness was observed only between vitellins from species within the same family. Amino acid compositional data for vitellins from nine species were used to assess homology by difference matrices. The S delta Q values were similar for both intra-order and inter-order comparisons and strongly suggested relatedness. The S delta n comparisons supported the immunological data that indicated that the vitellins were evolving rapidly. For most insect vitellins there are two distinct size classes of polypeptides that seem to be derived from a single asymmetric proteolytic cleavage of a precursor. We propose a model that suggests that the different size polypeptides represent distinct domains and that in the evolution of the vitellogenin genes of the Diptera and Hymenoptera there has been domain elimination.

Amino Acid Sequence↗

PubMed1982

Synthesis of virus-specific polypeptides and genomic RNA during the replicative cycle of Pichinde virus.

A stock of plaque-purified Pichinde virus, prepared under conditions designed to limit the amounts of defective interfering virus, was used to infect BHK cells. At daily intervals after infection, cells were examined for infectious and radiolabeled virus particle production and for the synthesis of virus-specific polypeptides. Quantitative comparisons were also made of the concentrations of genomic Pichinde virus L and S RNAs in the cytoplasm of infected cells on different days after infection. Our results showed that virus particle production, rates of protein synthesis, and the intracellular levels of viral genomic RNAs all increased and decreased with similar kinetics, and that this regulation was independent of the cell growth cycle. We were unable to relate these changes in viral macromolecule and virus production to the appearance of readily identifiable defective interfering particles. Our findings suggest that regulation of virus replication early during the replicative cycle of Pichinde virus may not be dependent upon the generation of defective interfering virus.

Animals↗

PubMed1981

Characterization of polypeptides immunoprecipitable from Pichinde virus-infected BHK-21 cells.

Using hamster anti-Pichinde virus serum, we immunoprecipitated polypeptides from BHK-21 cells infected with Pichinde virus. Seven immunoprecipitable polypeptides exhibited a time- and multiplicity of infection-dependent appearance when the cultures were pulse-labeled with L-[35S]methionine for 1 h. The predominant polypeptide was a nucleoprotein (NP) of 64,000 daltons. Components of 48,000, 38,000, and 28,000 daltons, when analyzed by two-dimensional tryptic peptide mapping, were found to be derived from NP. After a 3-h chase period, polypeptides of 17,000, 16,500, and 14,000 daltons were evident, and peptide mapping revealed that these three polypeptides were also related to NP. During a series of pulse-chase experiments, a 79,000-dalton glycoprotein (GPC) was cleaved to glycoproteins of 52,000 and 36,000 daltons. Radiolabel in a polypeptide of approximately 200,000 daltons (L) did not chase into smaller cleavage products. L, GPC, and NP were found to be unique by two-dimensional tryptic peptide mapping. Comparison of polypeptides immunoprecipitated from infected cells with structural components of purified virus revealed that L protein was evident in both. This is the first report of a high-molecular-weight polypeptide in Pichinde virus particles and infected cells.

Animals↗

PubMedDate not supplied

Epstein-Barr virus in non-Hodgkin's lymphomas and lymphoid tissue in children.

In developed countries the majority of adolescent children show serological evidence of past Epstein-Barr virus (EBV) infection. This virus is associated with non-Hodgkin's lymphomas in immunocompromised children, but the relationship of EBV DNA to these tumors in children without documented immunodeficiency has not been investigated by the polymerase chain reaction (PCR). We used a PCR method with primers from the Bam W and Bam HI regions to study non-Hodgkin's lymphomas in children, with tonsillar tissue of age-matched children as controls for the presence of EBV DNA. Six of the 20 tonsils were positive using the Bam W primers; another four showed this DNA with Bam HI primers. EBV DNA was detected in only one tumor (a lymphoblastic lymphoma) by both primer sets. The demonstration of EBV DNA in the tonsils reflects past infections and the incidence is in accordance with that expected from serologic epidemiological studies. The absence of demonstrable EBV DNA in 19 lymphomas suggests that this virus is of little consequence in the pathogenesis of non-Hodgkin's lymphomas in children who are not known to be immunocompromised. The lymphoblastic lymphoma had a mixed cell population, and the virus was not necessarily related to the malignancy.

Base Sequence↗