Iridovirus in the root weevil Diaprepes abbreviatus.

Invertebrate iridescent virus 6 (IIV6) was evaluated for mode of transmission and ability to cause infection in the root weevil, Diaprepes abbreviatus (L.). This is the first evidence of IIV6 infection in D. abbreviatus, which caused both patent and sub-lethal covert infections in both larvae and adults. Adults and larvae were successfully infected with IIV6 by puncture, injection and per os. Transmission of IIV6 was demonstrated between infected and healthy individuals regardless of gender. Virus was detected in egg masses produced by virus-infected females suggesting IIV6 is transmitted transovarially. Virus particles were observed in the cytoplasm of weevil cells, and were shown to infect fat bodies, muscle, and nerve tissues, as visualized using transmission electron microscopy. Patent infections resulted in death of individuals within 3 to 4 days post infection. Individuals with covert infections tested positive for virus infection on day 7 by polymerase chain reaction analysis. Sequencing of PCR amplicons confirmed virus infection. Discovery of new pathogens against root weevils may provide new management tools for development of control strategies based on induced epizootics. This is the first report of a virus infecting D. abbreviatus.

Alkaline phosphatase activity in whitefly salivary glands and saliva.

Alkaline phosphatase activity was histochemically localized in adult whiteflies (Bemisia tabaci B biotype, syn. B. argentifolii) with a chromogenic substrate (5-bromo-4-chloro-3-indolylphosphate) and a fluorogenic substrate (ELF-97). The greatest amount of staining was in the basal regions of adult salivary glands with additional activity traced into the connecting salivary ducts. Other tissues that had alkaline phosphatase activity were the accessory salivary glands, the midgut, the portion of the ovariole surrounding the terminal oocyte, and the colleterial gland. Whitefly nymphs had activity in salivary ducts, whereas activity was not detected in two aphid species (Rhodobium porosum and Aphis gossypii). Whitefly diet (15% sucrose) was collected from whitefly feeding chambers and found to have alkaline phosphatase activity, indicating the enzyme was secreted in saliva. Further studies with salivary alkaline phosphatase collected from diet indicated that the enzyme had a pH optimum of 10.4 and was inhibited by 1 mM cysteine and to a lesser extent 1 mM histidine. Dithiothreitol, inorganic phosphate, and ethylenediaminetetraacetic acid (EDTA) also inhibited activity, whereas levamisole only partially inhibited salivary alkaline phosphatase. The enzyme was heat tolerant and retained approximately 50% activity after a 1-h treatment at 65 degrees C. The amount of alkaline phosphatase activity secreted by whiteflies increased under conditions that stimulate increased feeding. These observations indicate alkaline phosphatase may play a role during whitefly feeding.

Discovering new insect viruses: whitefly iridovirus (Homoptera: Aleyrodidae: Bemisia tabaci).

Adult whiteflies, Bemisia tabaci (Gennadius), collected from the field were screened for viral pathogens using a cell line from the silverleaf whitefly, B. tabaci, B biotype (syn. B. argentifolii). Homogenates from the field-collected whiteflies were applied to cell cultures and checked for cytopathic effects (CPE). Cells were observed to develop cytoplasmic inclusions and to have a change in morphology. Cells displaying CPE were observed using a transmission electron microscope and found to be infected with a virus. The virus particles had an icosahedral shape and an approximate size of 120-130 nm. The virus was observed in defined areas of the cytoplasm adjacent to the cell nucleus. Analysis using polymerase chain reaction, Southern blot hybridization, and DNA sequencing confirmed that the virus discovered infecting the whitefly cell cultures was an iridovirus. Sequence analysis showed that the amplimer (893 bp) had a 95% homology to the invertebrate iridescent virus type 6 major capsid protein gene. Discovery of new viruses of whiteflies may provide renewed interest in using pathogens in the development of innovative management strategies. This is the first report of an iridescent virus isolated from whiteflies, B. tabaci, collected from the field.

Sequence and analysis of the genome of a baculovirus pathogenic for Lymantria dispar.

The genome of the Lymantria dispar multinucleocapsid nucleopolyhedrovirus (LdMNPV) was sequenced and analyzed. It is composed of 161,046 bases with a G + C content of 57.5% and contains 163 putative open reading frames (ORFs) of >/=150 nucleotides. Homologs were found to 95 of the 155 genes predicted for the Autographa californica MNPV (AcMNPV) genome. More than 9% of the LdMNPV genome was occupied by 16 repeated genes related to AcMNPV ORF2. Readily identifiable homologs of several genes that have been reported to play important roles in the AcMNPV life cycle are not present; these include ie-2, a transcriptional transactivator, and gp64, a major envelope glycoprotein of the nonoccluded form of the virus. A number of genes lacking in AcMNPV but present in other baculoviruses were identified; these include two viral enhancing factor homologs, a second copy of a conotoxin-like gene, and a dutpase homolog. Although a single gene predicted to encode a large subunit of ribonucleotide reductase was found, two different copies of the small subunit gene were present. In addition, homologs of genes not previously reported for baculoviruses were identified, including a predicted protein with homology to DNA ligases and another that has motifs most closely related to a yeast mitochondrial helicase. Thirteen homologous regions (hrs) containing 54 repeated sequences that include 30-bp imperfect palindromes were identified. The imperfect palindromes are related to those from other baculoviruses.

Evolving roles of life and health sciences librarians for the twenty-first century.

The twenty-first century will provide exciting challenges for life and health sciences librarians that will force us to redefine our position in the world of information. This rapidly changing environment influences the profession in a variety of ways including whom we serve and through what service, how and where we practice librarianship, and even the very composition of the profession itself. We must look at the changes in society and make the appropriate reciprocal changes in how we educate future librarians, how we market the profession, and how we develop the profession as a whole. We, as life and health sciences librarians, need to meet these challenges head on in order to continue the evolution of the profession well into the twenty-first century.

Differential stability of baculovirus late transcription complexes during initiation and elongation.

An in vitro system for baculovirus late transcription was developed that allows comparison of conditions that affect transcription initiation and elongation. A series of synthetic promoters was constructed based on the baculovirus late p6.9 promoter. The modified promoters were designed with a cytidine-free region downstream of the late promoter in order to yield paused transcripts of defined lengths in the absence of CTP. Transcription was found to be more efficient from a supercoiled template than from a linear template for this promoter. The stalled transcription complex remained competent and could be elongated in the presence of a full set of nucleotides. This made it possible to separately test the effects of heat treatment and inhibition by sarkosyl and heparin on initiation and elongation. Elongation complexes were more resistant than initiation complexes to each of these treatments. Furthermore a 1-2 mM MgCl2 concentration is critical for optimal initiation, but elongation can proceed in the presence of MgCl2 concentrations as high as 20 mM.

The sequence of the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus genome.

The nucleotide sequence of the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus (OpMNPV) genome was completed and analyzed. It is composed of 131,990 bases with a G + C content of 55% and contains 152 putative genes of 150 nucleotides or greater. Major differences in gene content and arrangement between OpMNPV and the Autographa californica MNPV were found. These include the presence in OpMNPV of three complete iap gene homologs, two conotoxin gene homologs, two protein tyrosine phosphatase homologs, and genes encoding homologs of dUTPase and the large and small subunits of ribonucleotide reductase. Seven major intergenic repeated regions were identified. Five of these are homologous regions that are related to similar regions from other baculoviruses.

Association of a baculovirus-encoded protein with the capsid basal region.

An open reading frame homologous to AcMNPV ORF9 (ORF1629) was characterized in the Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis virus (OpMNPV). Sequence analysis indicated that the OpMNPV homolog (called ORF2) encoded a protein predicted to contain 545 amino acids with a molecular weight of 61 kDa. The first 80 amino acids did not have a counterpart in the AcMNPV homolog. The remainder of the ORF was poorly conserved with 29% amino acid identity overall with the AcMNPV ORF. However, the amino terminal 150 amino acids of AcMNPV ORF9 demonstrated about 45% amino acid sequence identity with OpMNPV ORF2 and conserved runs of proline residues were present in internal regions of both molecules. Transcriptional mapping indicated the ORF2 transcripts were initiated at a late promoter sequence, ATAAG, beginning about 24 hr p.i. These transcripts terminated near the 3' end of the ORF2 reading frame. Antibodies were produced against a fusion protein derived from the bacterial gene encoding the maltose binding protein and most of the ORF2 sequence. These antibodies reacted with a protein of 69 kDa on Western blots and the protein was found to be associated with virions isolated from both polyhedra and budded virus. The OpMNPV ORF2 antiserum also reacted with the AcMNPV ORF9 gene product. Immunoelectron microscopic analyses indicated that ORF2 was associated with the ends of the capsids which contain the basal structure. This end appears to be oriented away from both the virogenic stroma and membranes involved in intranuclear envelopment. In addition, as virions bud from the nucleus into the cytoplasm, this end also appears to be oriented away from the nuclear membrane.

Collaboration in a continuum of learning: developing the next generation of leadership.

A project to create a lifelong learning community among health sciences library and information professionals by demonstrating the potential for using complementary technologies to provide access to a full range of educational experiences as recommended in Platform for Change, the Medical Library Association's educational policy statement, is described. The cooperative project brings together the rich continuing education tradition of the Medical Library Association, the experience of the University of South Carolina in distance education, and the Library and Information Science Distance Education Consortium to create a virtual campus through which health sciences library professionals may engage in lifelong learning.

Purification of a virus-induced RNA polymerase from Autographa californica nuclear polyhedrosis virus-infected Spodoptera frugiperda cells that accurately initiates late and very late transcription in vitro.

The virus-induced RNA polymerase from Autographa californica nuclear polyhedrosis virus-infected Spodoptera frugiperda cells was separated from the three host nuclear RNA polymerases by DEAE-Sephadex chromatography and then purified through two more steps: heparin-agarose chromatography and glycerol gradient ultracentrifugation. Fractions from each of these purification steps have been assayed in vitro for the ability to perform accurate initiation of transcription on a late (p6.9) and a very late (polyhedrin) template using primer extension analysis. In each case, the ability to accurately initiate transcription of these genes coincided with the virus-induced polymerase activity. Only after the glycerol gradient ultracentrifugation step did significant amounts of nonspecific late initiation occur, but specific late initiation was still readily detectable, suggesting that there is a limited number of late transcription factors, or that the factors are stably bound in a complex. After the glycerol gradient ultracentrifugation step, SDS-PAGE showed fewer than 10 prominent polypeptides remaining in the active fractions, which suggests a high degree of purity of the transcription machinery.

Temporal expression and immunogold localization of Plodia interpunctella granulosis virus structural proteins.

Monospecific antisera were produced against four structural proteins (VP12, VP17, VP31, and granulin) of the Plodia interpunctella granulosis virus using polypeptides derived by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or acid extraction. The antisera were shown to be specific on immunoblots of SDS-PAGE separated granulosis virus and were further used to detect structural proteins in infected fat body lysates. Immunoblots of fat body lysates from early stages of infection indicated that VP12, VP17, VP31, and granulin were expressed by 2.5 days post-infection. Immunogold labeling of the virus using the monospecific antisera and electron microscopy confirmed earlier reports that granulin is located in the protein matrix, V17 is an envelope protein, and VP31 is a capsid protein.

Phosphate cycling on the basic protein of Plodia interpunctella granulosis virus.

The presence of infected cell-specific phosphoproteins was investigated in Plodia interpunctella granulosis virus (PiGV)-infected fat body using [32P]orthophosphoric acid labeling. One infected cell-specific phosphoprotein had a mobility similar to that of the basic protein (VP12) of PiGV. Further analysis, using immunoblotting and acid-urea gel analysis of infected fat body, confirmed that this phosphoprotein was VP12. However we did not detect phosphorylated VP12 in 32P-labeled nucleocapsids. Phosphoamino acid analysis of 32P-labeled VP12 revealed that phosphoserine was present in the basic protein. Since VP12 is phosphorylated in the infected cell, but not in the nucleocapsid, it appears that dephosphorylation of VP12 is a critical event in the life cycle of the virus. We therefore assayed virus nucleocapsids and infected fat body for the presence of phosphatase activity. Phosphatase activity was not detected in the virus, but the infected fat body had more activity than uninfected fat body. A model for nucleocapsid assembly and uncoating is presented which takes into account the phosphorylation state of VP12, the role of Zn2+ in the nucleocapsid, and the role of the capsid-associated kinase.

Lipid and fatty acid analysis of the Plodia interpunctella granulosis virus (PiGV) envelope.

Virus envelope was isolated from Plodia interpunctella granulosis virus, produced in early fourth-instar larvae. Both polar and neutral lipids were analyzed by two-dimensional thin-layer chromatography. Fatty acid composition of various individual neutral and polar lipids was determined by gas-liquid chromatography. The major components of envelope neutral lipid were diacylglycerols. Palmitic acid and stearic acid were the major saturated fatty acids in both polar and neutral lipids. Whereas palmitoleic acid was the major unsaturated fatty acids in neutral lipids, oleic acid was the major unsaturated fatty acid in the polar lipids.

Evidence for zinc binding by two structural proteins of Plodia interpunctella granulosis virus.

Workers in our laboratory previously reported the possibility of cation involvement in the in vitro dissociation of the Plodia interpunctella granulosis virus nucleocapsids (K. A. Tweeten, L. A. Bulla, Jr., and R. A. Consigli, J. Virol. 33:866-876, 1980; M. E. Wilson and R. A. Consigli, Virology 143:516-525, 1985). The current study found zinc associated with both granulosis virus nucleocapsids and granulin by atomic absorption analysis. A blotting assay with 65Zn2+ specifically identified the radioactive cation as binding to two viral structural proteins, granulin and VP12. These findings indicate that zinc may have a critical role in maintaining virus stability.

Saccadic eye movements and eye-head coordination in children.

The eye and head movements of nine children, ages 6 through 10, were measured in order to establish quantitative characteristics of eye movements and eye-head corrdination patterns of children with normal vision and reading levels. The relationship between saccade amplitude and duration was linear, but the slope of this relationship indicated that saccades in children may have higher velocities than they do in adults. One of three temporal patterns of head and saccadic eye movement occurred during shifts of gaze to visual targets, depending on the temporal and spatial predictability of the target. It is suggested that quantitative measurements such as these could be used to examine developmental characteristics of eye and eye-head movement control.