Congenital Cytomegalovirus Infection: Clinical,Pathological and Virological Studies of Two Fatal Cases

Two infants severely ill at birth as a result of congenital cytomegalovirus infection were born in Halifax, Nova Scotia, in April and July 1968. Both died within seven weeks. Clinical, pathological and virological studies including serology and electron microscopy were made both before and after death. Cytomegalovirus was isolated in tissue culture from urine specimens from both infants during life and from organ tissues, blood and ascitic fluid after death. Large inclusion-bearing cells mixed with the erythrocytes and leukocytes were seen within the lumina of pulmonary blood vessels. A brief general discussion is presented of the various clinical manifestations of congenital cytomegalovirus infection and of the different serum antibody patterns found in these two pairs of mothers and infants.     

Critical Arginine Residue for Maintaining the Bacteriophage Tail Structure

The addition of 0.2 m l-arginine to various T-even bacteriophage preparations inactivated the virus preparations irreversibly. The virus particles were even more sensitive to added d-arginine and l-homoarginine than to l-arginine but were unaffected by arginine analogues with either an altered carboxyl group or guanidyl group. Treatment of phage T2H with 2,3-butanedione, a reagent which specifically reacts with the guanidyl portion of arginine residues, resulted in the apparent in-activation of most of the virus particles. However, after incubation of the treated particles at pH 7.5 at 37 C for 1 hr in the absence of butanedione, the original virus titer almost completely returned. The reactivation was completely inhibited by the presence of 0.2 m d-arginine. It appeared that the virus protein coat was sufficiently plastic so that the initial conformational change resulting from the alteration of an arginine residue (to possibly an ornithine residue) was at least partially reversible and that the virus tail proteins then refolded to produce a stable and active virus particle. These reactivated virus particles were not sensitive to inactivation by d-arginine but could now be rapidly inactivated by l-ornithine. Virus particles inactivated by arginine have altered tail structures. They have contracted tail sheaths still attached to tail plates and still contain tail cores. These properties of virus particles indicate that there is a free carboxyl group and a guanidyl group spatially equivalent to an arginine residue on one component of the virus tail which bind reversibly by means of polar linkages to another tail component. These bonds maintain the integrity of the virus tail. Added arginine appears to compete with this endogenous viral arginine for the binding sites and then to favor an irreversible conformational change.     

Global Expression Analysis of the Yeast Lachancea (Saccharomyces) kluyveri Reveals New URC Genes Involved in Pyrimidine Catabolism

Pyrimidines are important nucleic acid precursors which are constantly synthesized, degraded, and rebuilt in the cell. Four degradation pathways, two of which are found in eukaryotes, have been described. One of them, the URC pathway, has been initially discovered in our laboratory in the yeast Lachancea kluyveri. Here, we present the global changes in gene expression in L. kluyveri in response to different nitrogen sources, including uracil, uridine, dihydrouracil, and ammonia. The expression pattern of the known URC genes, URC1-6, helped to identify nine putative novel URC genes with a similar expression pattern. The microarray analysis provided evidence that both the URC and PYD genes are under nitrogen catabolite repression in L. kluyveri and are induced by uracil or dihydrouracil, respectively. We determined the function of URC8, which was found to catalyze the reduction of malonate semialdehyde to 3-hydroxypropionate, the final degradation product of the pathway. The other eight genes studied were all putative permeases. Our analysis of double deletion strains showed that the L. kluyveri Fui1p protein transported uridine, just like its homolog in Saccharomyces cerevisiae, but we demonstrated that is was not the only uridine transporter in L. kluyveri. We also showed that the L. kluyveri homologs of DUR3 and FUR4 do not have the same function that they have in S. cerevisiae, where they transport urea and uracil, respectively. In L. kluyveri, both of these deletion strains grew normally on uracil and urea.     

SURVIVAL OF AN UNIRRADIATED SALMONELLA TYPHIMURIUM MARKER STRAIN INOCULATED IN POULTRY FEEDS AFTER IRRADIATION

The present study was designed to compare unirradiated Salmonella typhimurium survival during storage after inoculation in either irradiated or unirradiated poultry feed. The effects of irradiation (5 kGy) on the indigenous feed microflora and on the survival of marker strain of S. typhimurium contaminated after irradiation treatment were determined during 56 days of storage of either soybean meal (SBM) or meat and bone meal (MBM) based feeds. The initial aerobic bacterial populations were reduced more than 90% in both SBM (4.96 to 4.08 ± 0.03 log₁₀ CPU/g feed) and MBM (5.12 to 3.90 ± 0.03) by irradiation. Irradiation treatment reduced the average fungal counts during 56 days of storage in both SBM (4.24 to 2.74 ± 0.03) and MBM (4.38 to 2.15 ± 0.03) containing feeds. However, unirradiated S. typhimurium populations inoculated after irradiation of the feed were not different in either irradiated or nonirradiated SBM and MBM based feeds. Therefore, the differences in fungal versus bacterial sensitivity among the feed types and storage times suggests that gamma irradiation can alter the makeup of indigenous microbial populations in feed but this does not appear to have a discernible influence on subsequent survival of unirradiated S. typhimurium added as a dry inoculum after irradiation.     

Reproductive patterns of selected understorey trees in the Malaysian rain forest: the sexual species

HA, C. O., SANDS, V. E., SOEPADMO, E. & JONG, K., 1988. Reproductive patterns of selected understorey trees in the Malaysian rain forest: the sexual species. Investigations were carried out on the floral, fruit and seed biology, and the embryology of representatives of the Sapindaceae and Bombacaceae which occur in the lower canopy of the lowland rain forest of Peninsular Malaysia. Pollination studies indicated cross-compatibility and outbreeding in all species examined, associated with self-compatibility in the polygamous monecious Pometia pinnata and Allophylus cobbe and, to a limited extent, in the effectively dioecious Xerospermum intermedium . In these sapindaceous species, together with the self-incompatible androdioecious Nephelium lappaceum , the structurally hermaphrodite flowers were determined embryologically to be functionally female with no anther dehiscence. The self-incompatible Durio griffithii of the Bombacaceae, and X. intermedium, N. lappaceum and P. pinnata were shown by embryological studies to form a sexual zygote. The observations on these outcrossing species are considered in relation to their potential for gene exchange and their contribution to the maintenance of species diversity in the lowland rain forest.