The sequence of a 20.15 kb region from human herpesvirus 6 variant B (HHV-6B) strain Z29 is described (GenBank accession number L14772). Determinations of protein homologies for seventeen predicted ...gene products revealed HHV-6B homologs of six proteins well-conserved both in genetic context and amino acid sequence throughout the alpha-, beta-, and gammaherpesvirus subfamilies. These include proteins involved in viral DNA replication, packaging and nucleotide metabolism, and conserved proteins of undefined function. The close evolutionary relationship of the human betaherpesviruses, HHV-6B, HHV-6A, HHV-7 and human cytomegalovirus (HCMV) was confirmed by identification of several protein sequences encoded only by these viruses, including homologs of the HCMV early phosphoprotein family and a series of HCMV open reading frames predicted to encode glycoprotein exons. Homologs of essential HSV-1 replication proteins, UL8 and UL9, were also identified. Downstream from the conserved replication locus, each betaherpesvirus contains a region of divergent, small open reading frames. The evolution of this region and its potential use in the development of a viral vector system are discussed.
The growth characteristics of human herpesvirus 7 strain SB (HHV-7 (SB)) were studied in human umbilical cord blood lymphocyte (CBL) cultures. The virus has approximately a 4-day growth cycle, as ...measured by immunofluorescence analysis, quantitation of the relative viral DNA concentration, and examination of infected cells by electron microscopy on consecutive days post-infection. By systematically varying the culture media components, improved culturing conditions were established. Activated lymphocytes were required for virus growth. HHV-7(SB) grew best in phytohemagglutinin-stimulated CBL cultured in media containing 0.01 mg/ml hydrocortisone. Addition of recombinant human interleukin 2 (IL-2) at concentrations exceeding 1–10 U/ml inhibited virus growth in most CBL cultures. Addition of exogenous IL-2 to the culture media had no effect on viral DNA production. However, the percentage of virus antigen-positive cells was highest when 0.1–1 U/ml was added to the media. Differences in the ability of individual CBL cultures to replicate HHV-7(SB) was not explained by differing CD4+ cell concentrations. However, individual cultures varied in the level of endogenous IL-2 production, which may contribute to the virus growth variability in CBL. HHV-7(SB) grew in the CD4-positive T-cell line SupT1, but not in a variety of other lymphocyte, fibroblast, or epithelial cell lines. Nine compounds were tested for antiviral activity against HHV-7 in vitro. Phosphonoformic acid inhibited virus growth with a 50% effective concentration of 4.8
μM. Ganciclovir (200
μM) and phosphonoacetic acid (100
μM) inhibited more than 90% of virus production. None of the compounds were cytotoxic at concentrations which inhibited the virus. A generalized increase in host cell protein synthesis was also observed in virus-infected cells similar to that seen in CBL infected with human herpesvirus 6.
The problems of stable-isotope studies to determine amino acid requirements and balance which relate to the way in which the traced amino acid is treated in calculation of balance. The work of Young ...et al (a theoretical basis for increasing current estimates of the amino acid requirements in adult man with experimental support) is featured
Most of 36 crabapple and 19 other woody plant taxa demonstrated the ability, when dormant, to grow a continuous row of callus along the cambial region on split-stem pieces within 5 to 7 days of ...incubation at 25 degrees C. The ability to grow callus after freezing tests was compared with discoloration and electrical conductivity for determining laboratory freeze injury to selected taxa. Hardiness levels were determined using the procedures of callus growth, discoloration, and electrical conductivity after freezing stem pieces of Jack crabapple Malus baccata (L.) Borkh. 'Jacki', pink bud Sargent crabapple M. sargentii Rehd. 'Rosea', Mary Potter crabapple Malus sp. 'Mary Potter', and snowberry mountainash Sorbus discolor (Maxim.) Maxim.. Sampling dates for laboratory freezing tests were chosen to represent midwinter cold hardiness and partial hardiness of either late fall or early spring. There was a high correlation between discoloration and callus ratings for most plants; however, the two methods usually did not identify the same critical temperature (T50) for injury. The critical temperatures identified by callus growth was often 3 to 6 degrees C lower than for discoloration. For many taxa, callus growth was easier to see than discoloration of cambium and phloem, providing a less subjective evaluation of injury. TTC (2,3,5-triphenyl tetrazolium chloride) treatment was sometimes useful to identify callus growth that died after forming. The critical temperature (Tc), the highest temperature at which relative electrical conductivity differed significantly from the control temperature, was higher in most cases, indicating less cold hardiness than the T50 for callus and discoloration. The callus procedure may have value for evaluating injury to the cambial zone from freezing and other plant stresses because it determines the ability of the plant to continue growth
Cercopithecine herpesvirus 1 (B virus), enzootic among monkeys of the genus Macaca, causes minimal morbidity in its natural host. In contrast, human B-virus infection presents as rapidly ascending ...encephalomyelitis with a fatality rate of ∼70%. This infection remains an uncommon result of macaque-related injuries, although the increase in the use of macaques for research on simian retrovirus infection and hepatitis has expanded the number of opportunities for human exposure. In response to this situation, Emory University and the Centers for Disease Control and Prevention jointly sponsored a B Virus Working Group to formulate a rational approach to the detection and management of human B-virus infection. The resulting guidelines are presented herein and are based upon information from published cases, unpublished cases managed by working-group members, knowledge of the behavior of herpes simplex virus, and—in the absence of hard data—the collective judgment of the group. Although consensus among the coauthors existed on the major points covered by these guidelines, opinions varied widely regarding specific recommendations.
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