Human cytomegalovirus (HCMV) smallest capsid protein identified as product of short open reading frame located between HCMV UL48 and UL49.

The capsid of cytomegalovirus contains an abundant, low-molecular-weight protein whose coding sequence within the viral genome had not been identified. We have used a combination of biochemical and immunological techniques to demonstrate that this protein, called the smallest capsid protein in human cytomegalovirus, is encoded by a previously unidentified 225-bp open reading frame (ORF) located between ORFs UL48 and UL49. This short ORF, called UL48/49, is the positional homolog of herpes simplex virus ORF UL35 (encoding capsid protein VP26) and shows partial amino acid sequence identity to positional homologs in human herpes viruses 6 and 7.     

Postoligomerization folding of human cytomegalovirus glycoprotein B: identification of folding intermediates and importance of disulfide bonding.

Human cytomegalovirus glycoprotein B (gB or UL55) has been demonstrated to be a disulfide-linked homodimer within the envelope of mature virions. Previously, it has been shown that gB undergoes a rapid dimerization nearly coincident with its synthesis. Following dimerization, the molecule slowly folds into a form which can be transported from the endoplasmic reticulum. In this study we have examined the prolonged folding of gB by using a set of defined gB-reactive murine monoclonal antibodies and gB expressed as a recombinant protein in the absence of other human cytomegalovirus proteins. Our results have documented a folding pathway consistent with the relatively rapid dimerization of the translation product followed by delayed conversion into a fully folded molecule. Assembly of the dominant antigenic domain of gB, AD-1, preceded dimerization and folding of the molecule. The fully folded dimer was heat stable, but its conformation was altered by treatment with 2% sodium dodecyl sulfate (SDS), whereas an oligomeric folding intermediate was both heat and SDS stable. Postoligomerization disulfide bond formation could be demonstrated during folding of gB, suggesting that the formation of these covalent bonds could contribute to the prolonged folding of this glycoprotein.     

A New Glucose-6-Phosphate Dehydrogenase Variant, G6PD Orissa (44 Ala→Gly), is the Major Polymorphic Variant in Tribal Populations in India

Deficiency of glucose-6-phosphate dehydrogenase (G6PD) is usually found at high frequencies in areas of the world where malaria has been endemic. The frequency and genetic basis of G6PD deficiency have been studied in Africa, around the Mediterranean, and in the Far East, but little such information is available about the situation in India. To determine the extent of heterogeneity of G6PD, we have studied several different Indian populations by screening for G6PD deficiency, followed by molecular analysis of deficient alleles. The frequency of G6PD deficiency varies between 3% and 15% in different tribal and urban groups. Remarkably, a previously unreported deficient variant, G6PD Orissa (44 Ala→Gly), is responsible for most of the G6PD deficiency in tribal Indian populations but is not found in urban populations, where most of the G6PD deficiency is due to the G6PD Mediterranean (188 Ser→Phe) variant. The K of G6PD Orissa is fivefold higher than that of the normal enzyme. This may be due to the fact that the alanine residue that is replaced by glycine is part of a putative coenzyme-binding site.     

Changes in the hypothalamic-hypophyseal-ovarian axis of primiparous sows following weaning or pulsatile gonadotropin releasing homrone administration and weaning

Lactating primiparous sows were used to examine relationships among hypothalamic gonadotropin releasing hormone (GnRH), serum, and anterior pituitary gonadotropins and follicular development after weaning or after administering GnRH pulses (1.5 ug) once hourly for 72 h before weaning. Control sows were either slaughtered at 0 or 72 h after weaning or were cannulated for collection of blood samples until 24 h after estrus. Sows pulsed with GnRH were either slaughtered 72 h after beginning of GnRH treatment or were cannulated for collection of blood samples until 24 h after estrus. Exogenous GnRH pulsed hourly during 72 h prior to weaning stimulated follicular growth as demonstrated by an increase in number of surface follicles >5 mm in diameter and a decrease in number of follicles <5 mm in diameter. Interval (h) from weaning to an increase in estradiol (>16 pg/ml) was less in GnRH-pulsed than in control sows (P < 0.05), but hours from weaning to estrus were similar between groups. Amounts of GnRH in the medial basal hypothalamus (MBH), stalk median eminence (SME), and hypophyseal portal area (HPA) were similar among control sows killed at 0 or 72 h and sows pulsed with GnRH. Serum concentrations of luteinizing hormone (LH) and frequency of release of LH were similar between GnRH-pulsed and control sows, but concentrations of LH and follicle stimulating hormone (FSH) in anterior pituitary were lower in GnRH-pulsed sows than control sows. Administration of GnRH for 72 h prior to weaning in primiparous sows stimulated follicular growth as manifested by increased secretion of estrogen; however, the amount of follicular growth was apparently inadequate to hasten the onset of estrus after weaning.     

Chronic histological effects of ultrasonic hyperthermia on normal feline brain tissue

The histopathological changes associated with ultrasonic heating of normal cat brain have been correlated with thermal distributions. Ultrasound energy was applied for 50 min at different intensities to generate tissue temperatures from 42 to 48 degrees C. Animals were sacrificed at various intervals from 1 to 56 days. The organization and resolution of thermal damage was characterized by three stages of histopathological changes within the nervous tissue. The acute stage (Days 1-3) was defined by (1) extensive coagulation necrosis, (2) pyknosis of neuronal elements in the gray matter, (3) edema and vacuolation in the white matter, and (4) polymorphonuclear leukocytes. The subacute stage (Days 3-21) was characterized by (1) the appearance of lipid-laden macrophages, (2) liquefaction of the necrotic regions, (3) fibroblastic proliferation, and (4) vascular proliferation with some perivascular inflammatory infiltration (lymphocytes). Lastly, the chronic stage (Days 21-56) was defined by (1) fibrosis (reticulin and collagen formation) and (2) gliosis (reactive astrocytic proliferation) occurring around the fluid-filled necrotic center. Analysis of these data has also included a study of the lesion size versus the dose (temperature for 50 min) of heating. The results demonstrate a significant linear dose-response correlation. The results of this study indicate that the histological appearance and time course of repair of thermal injury in the normal brain tissue are analogous to acute brain necrosis resulting from cerebral infarction, except the thermal damage does not result in significant hemorrhage.     

Fertility of dairy cattle treated with human chorionic gonadotropin (hCG) to stimulate progesterone secretion

Two experiments were conducted to determine if progesterone secretion and fertility would be affected by administration of human chorionic gonadotropin (hCG) before or after the first insemination. In Experiment 1, 48 Holstein heifers received 1000 IU of hCG or 1 ml of saline on Days 2, 3, and 4 of an estrous cycle. They were inseminated at the subsequent estrus. In Experiment 2, 110 Jersey and 105 Holstein cows received a single injection of 5000 IU of hCG or 5 ml of saline on Day 3 after estrus. These cows were first inseminated either at the estrus immediately preceding treatment or at the subsequent estrus. In both experiments, blood samples for determination of progesterone were collected thrice weekly for 3 to 4 wk following treatment. In Experiment 1, progesterone concentrations during mid-cycle were higher in hCG-treated heifers than in saline-treated controls. Treatment with hCG resulted in an 11% increase in the first service conception rate (P < 0.48). In Experiment 2, hCG-treated cows displayed higher progesterone secretion during mid-cycle than saline-treated herdmates. The conception rate of cows inseminated prior to hCG-treatment was not affected by treatment, but cows inseminated after treatment had a marginally lower fertility rate. The conception rate of cows receiving a repeat insemination following hCG treatment was higher than for the controls. We conclude that treatment with hCG did not improve the conception rate at the first insemination, but it may be beneficial for cows that require a repeat service.     

The manganese site of the photosynthetic oxygen-evolving complex probed by EPR spectroscopy of oriented photosystem II membranes: the g = 4 and g = 2 multiline signals.

The g = 4 and g = 2 multiline EPR signals arising from the Mn cluster of the photosynthetic oxygen-evolving complex (OEC) in the S2 state were studied in preparations of oriented photosystem II (PSII) membranes. The ammonia-modified forms of these two signals were also examined. The g = 4 signal obtained in oriented PSII membranes treated with NH4Cl at pH 7.5 displays at least 16 partially resolved Mn hyperfine transitions with a regular spacing of 36 G [Kim, D.H., Britt, R.D., Klein, M.P., & Sauer, K. (1990) J. Am. Chem. Soc. 112, 9389-9391]. The observation of this g = 4 "multiline signal" provides strong spectral evidence for a tetranuclear Mn origin for the g = 4 signal and is strongly suggestive of a model in which different spin state configurations of a single exchange-coupled Mn cluster give rise to the g = 4 and g = 2 multiline signals. A simulation shows the observed spectrum to be consistent with an S = 3/2 or S = 5/2 state of a tetranuclear Mn complex. The resolution of hyperfine structure on the NH3-modified g = 4 signal is strongly dependent on sample orientation, with no resolved hyperfine structure when the membrane normal is oriented perpendicular to the applied magnetic field. The dramatic NH3-induced changes in the g = 4 signal resolved in the spectra of oriented samples are suggestive that NH3 binding at the Cl- site of the OEC may represent direct coordination of NH3 to the Mn cluster.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrastructure ofDigitalis lanata tissue cultures

Summary The anatomy of twoDigitalis lanata tissue culture strains, S-1 and S-2, has been studied. The cardenolide accumulating cell aggregates consisted of highly vacuolated cells with very lobed nuclei in the periphery and a central part of meristematic cells. Sieve tube elements and companion cells and tracheids were observed in some of the cultures. The effect of gibberellic acid (GA₃) and SAN 9789 on the ultrastructure of the cultures was most apparent as regards the plastids and the amounts of mitochondria and ER. The content of starch seemed to be highest in the cardenolide accumulating strain S-2 grown in darkness (S-2 D) with or without GA3, but considerable amounts were also found in S-1 grown in darkness (S-1 D) with or without GA₃, which did not accumulate cardenolides. The amount of plastoglobuli was increased in S-1 by SAN treatment. It was also higher in S-2 D and S-2 D+GA₃ than in S-1 D and S-1 D+GA₃; i.e., it was high in tissues with blocked carotene synthesis. Many large plastoglobuli were also observed in apparently degenerating cells. The amount of ER seemed relatively high in cardenolide producing cultures. The amount of mitochondria was highly variable, but no correlation with cardenolide accumulation could be found.Abbreviations D dictyosome - ER endoplasmic reticulum - M mitochondrion - N nucleus - P plastid - PG plastoglobule - S starch grain - SC sieve cell - V vacuole - W cell wall - GA₃ gibberellic acid - S-1D strain S-1 cultured in darkness - S-1 L strain S-1 cultured in light - S-2 D strain S-2 cultured in darkness - S-2L8 strain S-2 previously cultured in darkness followed by 8 days in light in the present study - SAN SAN 9789 (Norflurazon) 4-chloro-5-(methylamino)-2-(,,,-trifluoro-m-tolyl)-3(2H)-pyridazinone