The Epstein-Barr Virus BDLF4 Gene Is Required for Efficient Expression of Viral Late Lytic Genes

Epstein-Barr virus (EBV) is a gammaherpesvirus, associated with infectious mononucleosis and various types of malignancy. We focused here on the BDLF4 gene of EBV and identified it as a lytic gene, expressed with early kinetics. Viral late gene expression of the BDLF4 knockout strain was severely restricted; this could be restored by an exogenous supply of BDLF4. These results indicate that BDLF4 is important for the EBV lytic replication cycle, especially in late gene expression.     

Studies on Flavor Components of Foodstuffs

Distribution of tetramethylpyrazine (T.M.P.) in Japanese fermented foodstuffs was investigated by more accurate analytical method.

Namely, the method was successful when trapping T.M.P. with picric acid after flash evaporation of the foodstuffs, followed by analysis with gas chromatography.

T.M.P. was detected in many Japanese fermented foodstuffs, especially in Miso, Soy sause and Natto, which suggests that alkylpyrazines may play an important role as flavor of those foodstuffs.     

Response of isolated rat iris dilator to adrenergic and cholinergic agents and electrical stimulation

Responses of isolated rat iris dilator to some agents and to electrical stimulation were examined. Norepinephrine and epinephrine produced contraction, which was antagonized by 0.03 μM phentolamine. Acetylcholine produced relaxation at low concentrations (1 nM ? 1 μM) as great as 80 % of the resting tone while contraction at high concentrations (≥1 μM). Both responses were suppressed by 0.02 μM atropine and enhanced by 0.03 μM physostigmine. Electrical stimulation at low voltage or low frequency (up to 10 Hz) elicited relaxation while stimulation at high voltage or high frequency (30 Hz) produced contraction. Stimulation with intermediate strength elicited biphasic response. The contraction and relaxation induced by electrical stimulation were abolished by 3 μM phentolamine or by 0.05 μM atropine, respectively. Both phases were abolished by tetrodotoxin (0.3 μM). It is suggested that in the rat the cholinergic relaxation of the dilator may assist the cholinergic contraction of the sphincter (1). The pronounced cholinergic relaxation of nonvascular tissue is to be noted.     

Phenotype Specific Analyses Reveal Distinct Regulatory Mechanism for Chronically Activated p53

The downstream functions of the DNA binding tumor suppressor p53 vary depending on the cellular context, and persistent p53 activation has recently been implicated in tumor suppression and senescence. However, genome-wide information about p53-target gene regulation has been derived mostly from acute genotoxic conditions. Using ChIP-seq and expression data, we have found distinct p53 binding profiles between acutely activated (through DNA damage) and chronically activated (in senescent or pro-apoptotic conditions) p53. Compared to the classical ‘acute’ p53 binding profile, ‘chronic’ p53 peaks were closely associated with CpG-islands. Furthermore, the chronic CpG-island binding of p53 conferred distinct expression patterns between senescent and pro-apoptotic conditions. Using the p53 targets seen in the chronic conditions together with external high-throughput datasets, we have built p53 networks that revealed extensive self-regulatory ‘p53 hubs’ where p53 and many p53 targets can physically interact with each other. Integrating these results with public clinical datasets identified the cancer-associated lipogenic enzyme, SCD, which we found to be directly repressed by p53 through the CpG-island promoter, providing a mechanistic link between p53 and the ‘lipogenic phenotype’, a hallmark of cancer. Our data reveal distinct phenotype associations of chronic p53 targets that underlie specific gene regulatory mechanisms.     

Culture-Independent Evaluation of Nonenveloped-Virus Infectivity Reduced by Free-Chlorine Disinfection

The inability of molecular detection methods to distinguish disinfected virions from infectious ones has hampered the assessment of infectivity for enteric viruses caused by disinfection practices. In the present study, the reduction of infectivity of murine norovirus S7-PP3 and mengovirus vMC0, surrogates of human noroviruses and enteroviruses, respectively, caused by free-chlorine treatment was characterized culture independently by detecting carbonyl groups on viral capsid protein. The amount of carbonyls on viral capsid protein was evaluated by the proportion of biotinylated virions trapped by avidin-immobilized gel (percent adsorbed). This culture-independent approach demonstrated that the percent adsorbed was significantly correlated with the logarithm of the infectious titer of tested viruses. Taken together with the results of previous reports, the result obtained in this study indicates that the amount of carbonyls on viral capsid protein of four important families of waterborne pathogenic viruses, Astroviridae, Reoviridae, Caliciviridae, and Picornaviridae, is increased in proportion to the received oxidative stress of free chlorine. There was also a significant correlation between the percent adsorbed and the logarithm of the ratio of genome copy number to PFU, which enables estimation of the infectious titer of a subject virus by measuring values of the total genome copy number and the percent adsorbed. The proposed method is applicable when the validation of a 4-log reduction of viruses, a requirement in U.S. EPA guidelines for virus removal from water, is needed along with clear evidence of the oxidation of virus particles with chlorine-based disinfectants.