Human cytomegalovirus (HCMV) ie1 deletion mutant CR208 is profoundly growth deficient after lowmultiplicity infection of primary fibroblasts. Previously, we showed that many fewer cells infected with CR208 at low multiplicity accumulated the delayed-early (DE) protein ppUL44 than accumulated the immediate-early 2 (IE2) p86 protein, indicating a high frequency of abortive infections. We now demonstrate that accumulation of all DE proteins tested was defective after low-multiplicity infection in the absence of IE1 p72. Accumulation of the DE proteins pUL57, pUL98, and pUL69 followed a pattern very similar to that of ppUL44 during low-multiplicity CR208 infection. Accumulation of the ppUL112-113 proteins occurred in a greater proportion of cells than other DE proteins during low-multiplicity CR208 infection, but was still deficient relative to wild-type virus. We also show for the first time that steady-state levels of many DE RNAs were reduced during low-multiplicity CR208 infection and that by in situ hybridization of the abundant cytoplasmic 2.7-kb TRL4 DE (␤2.7) RNA, a viral DE RNA followed a defective pattern of accumulation similar to that of ppUL44. Furthermore, transfected DE promoter-reporter constructs were found in transient assays to be considerably less responsive to CR208 infection than to infection by wild-type Towne virus. Our results indicate a general defect in DE gene expression following low-multiplicity HCMV infection in the absence of functional IE1 p72, most probably mediated by reduced transcription of DE genes and by the reduced accumulation of DE RNAs.Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus which infects between 50 and 100% of the human population, depending on the population group tested. Primary infection is generally asymptomatic or not diagnosed, with the virus persisting lifelong in the host. However, HCMV becomes a significant medical problem in individuals with immature or compromised immune systems (11). As in other herpesviruses, viral gene expression during productive infection occurs in an ordered temporal cascade, with immediateearly (IE or ␣), delayed-early (DE or ␤), and late (L or ␥) kinetics (50). Expression of immediate-early genes is a prerequisite for progression into the delayed-early phase of virus growth and the subsequent replication of viral DNA, which is in turn required for late-phase entry and virion assembly and release.Two major IE proteins (IE1 p72 and IE2 p86) are expressed, their messages generated by alternate splicing of a single RNA transcript from the major immediate-early (MIE) locus. IE2 p86 is thought to be the major transcription-activating protein of HCMV and is also responsible for negative autoregulation of the major immediate-early promoter (MIEP) (51). Transient-cotransfection assays have shown the specific activation of viral and cellular promoters by IE2 p86 (37,50,75). Specific DNA binding sites for IE2 p86 have been found in the upstream regions of promoters activated by IE2 p86 (6,9,69,70) and at the cap site of the MIE...

Fumigation of high-containment microbiology facilities is an international requirement and in the UnitedKingdom this process is still commonly undertaken using formaldehyde vaporization. Formaldehyde usage is simple and inexpensive, but concerns exist over its toxicity and carcinogenicity. Alternative fumigants exist, although independent, parallel comparison of these substances is limited. This study determined the level of biocidal efficacy achievable with formaldehyde and compared this with other commonly used fumigants. Three different hydrogen peroxide-based fumigation systems were evaluated (two vapor and one dry-mist methods), along with true gas systems employing ozone and chlorine dioxide. A range of challenge microorganisms was used at different room locations to assess the efficacy, usability, and safety of the fumigation equipment. These microorganisms included Geobacillus stearothermophilus, Clostridium difficile, Mycobacterium fortuitum, and Vaccinia virus. Only chlorine dioxide and formaldehyde fumigants gave consistently high levels of antimicrobial efficacy across all bacterial challenge tests (typically greater than a 5-log reduction). All systems performed similarly against Vaccinia virus, but variable results were noted for Geobacillus, C. difficile, and M. fortuitum for the hydrogen peroxide-and ozone-based systems. The study also revealed inconsistencies in system reliability and reproducibility, with all fumigant systems aborting midcycle on at least one occasion. In contrast, formaldehyde fumigation was confirmed as extremely reliable, largely because of its simplicity (liquid plus hot plate). All the fumigants tested have UK workplace exposure limits of 2 ppm or less, yet residual fumigant was detected for the formaldehyde and hydrogen peroxide systems following cycle completion, even after room aeration. Articles

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Infection of human B cells with Epstein-Barr virus (EBV) results in activation of the cell cycle and cell growth. To interpret the mechanisms by which EBV activates the cell, we have assayed many proteins involved in control of the G0 and G1phases of the cell cycle and regulation of apoptosis. In EBV infection most of the changes, including the early induction of cyclin D2, are dependent on expression of EBV genes, but an alteration in the E2F-4 profile was partly independent of viral gene expression, presumably occurring in response to signal transduction activated when the virus binds to its receptor, CD21. By comparing the expression of genes controlling apoptosis, including those encoding several members of the BCL-2 family of proteins, the known relative resistance of EBV-immortalized B-cell lines to apoptosis induced by low serum was found to correlate with expression of both BCL-2 and A20. A20 can be regulated by the NF-κB transcription factor, which is known to be activated by the EBV LMP-1 protein. Quantitative assays demonstrated a direct temporal relationship between LMP-1 protein levels and active NF-κB during the time course of infection.