Nitric oxide mediates immunosuppression induced by Listeria monocytogenes infection: quantitative studies.

Our laboratory has shown that immunization of mice with an attenuated strain of Salmonella typhimuriuminduces profound suppression in the capacity of splenocytes to mount an in vitro antibody plaque-forming cell (PFC) response to sheep red blood cells (SRBC) and to proliferate in response to mitogens. In vitro addition of NG-monomethyl-L-arginine (NMMA), an inhibitor of nitric oxide (NO) synthase, to cell cultures from Salmonella-immunized mice completely blocked suppression of the PFC responses, implicating that NO is the suppressor factor. The present study quantified the role of nitric oxide in immunosuppression induced by Listeria monocytogenes, a gram positive intracellular pathogen of macrophages.

Electrophysiological properties of neonatal rat ventricular myocytes with alpha1-adrenergic-induced hypertrophy.

The electrophysiology of neonatal rat ventricular myocytes with and without hypertrophy has not been characterized. The alpha1-adrenergic agonist phenylephrine induced hypertrophy in neonatal rat ventricular myocytes. After 48 h of exposure to 20 microM phenylephrine, cell surface area of hypertrophied myocytes was 44% larger than control.

Expression cloning of a rat testicular transcript abundant in germ cells, which contains two leucine zipper motifs.

The aim of the present study was to identify specific, novel germ cell markers that could be used to monitor normal and abnormal spermatogenesis. Of several cloned cDNAs isolated from an adult rat testis cDNA library using an expression screening strategy, clone 813B4 (700 base pairs) hybridized exclusively to three mRNA transcripts in samples isolated from rat testes on and after Day 21 of life and to epididymides from some, but not all, adult rats. After further screening, two identical clones encoding a 2.

Expression of oestrogen receptor beta (ER beta) in multiple rat tissues visualised by immunohistochemistry.

Steroid hormones regulate cell function via specific receptors, members of a super family of ligand activated transcription factors, expressed in their target tissues. A second oestrogen receptor (ER beta) has recently been shown by RT-PCR to have a wide tissue distribution distinct from that of oestrogen receptor alpha (ER alpha). We have raised a polyclonal antiserum using a peptide specific for ER beta in order to determine the cellular sites of expression of the receptor.

Investigation of the potential role of the germ cell complement in control of the expression of transferrin mRNA in the prepubertal and adult rat testis.

Iron is required for the normal development of germ cells during spermatogenesis. Because these cells have no direct access to systemic iron, there exists a shuttle system involving production and secretion of the iron-transporting protein transferrin by the Sertoli cells. Previous reports using cultures of immature Sertoli cells exposed to adult germ cells, or in vivo studies involving germ cell depleted adult rat testes, concluded that production of transferrin by Sertoli cells is modulated by germ cell complement.

Effect of body composition at selection on reproductive development in large white gilts.

Fifty-four Large White gilts were used to determine the effect of body composition at selection (145 d of age) on the onset of puberty and subsequent reproductive development until 202 d of age. Gilts were assigned to one of three groups based on their backfat depth at selection: 10 to 12 mm (L), 13 to 15 mm (M), and 16 to 18 mm (F). All of the F gilts, 92% of the M gilts, and 67% of the L gilts reached puberty by slaughter at 202 d of age.

Reduced ischemia and reperfusion injury following exercise training.

We examined the effects of two exercise training modalities, i.e., low-intensity endurance and sprint running, on in vitro, isovolumic myocardial performance following ischemia and reperfusion.

Wind protection effects and airflow patterns in outside feedlots.

Steers were finished in three different sets of outside lots: 1) pens with overhead shelter on the north side; 2) pens south and southeast of a shelterbelt; and 3) pens with no shelter or windbreak. In trials conducted over a 3-yr period with predominantly British and British x Continental crossbred yearlings, performance improvements due to providing shelter or wind protection in the winter were not detected; however, in the summer, providing wind protection or shelter resulted in decreased (P < .10) cattle gains.

Expression of protamine P2 in the testis of the common marmoset and man visualized using non-radioactive in-situ hybridization.

Information on the organization of the spermatogenic cycle of the common marmoset (Callíthrix jacchus), a small New World primate, is limited to a single histological report on the differentiation of spermatids. In the present study we have used non-radioactive in-situ hybridization with a cRNA probe directed against marmoset protamine 2, on fixed sections of marmoset and human testis to elucidate the organization of mature germ cells within the seminiferous epithelium. Specificity of the probe was checked on Northern blots; mP2 hybridized exclusively to mRNA in samples extracted from marmoset and human testis.

Colocalization of mRNA and protein using in situ hybridization and immunohistochemistry in testicular tissue.

Using testes fixed by perfusion with Bouin's fluid and embedded in paraffin wax, this study has established methods for combining in situ hybridization and immunocytochemistry on the same section to colocalize mRNA and protein for transition protein-1 (TP-1) and sulfated glycoprotein-1 (SGP-1), respectively. It was found that SGP-1 could be detected in tissue sections subsequent to the detection of TP-1 mRNA in situ. The finding that 1) the tissue pretreatments required to permeabilize the section and to allow access to the probe, and 2) the hybridization conditions themselves, had no adverse effect on the detection of antigen, eases the performance of this technique.

Phosphatidylethanolamine binding protein is an abundant secretory product of haploid testicular germ cells in the rat.

An abundant cellular and secretory product of isolated seminiferous tubules from adult rats was identified as having an apparent molecular weight of approximately 24,000 and a pI of 5.3 on autoradiographs of two-dimensional polyacrylamide gels. A protein with identical migration characteristics was identified as a major secretory product of isolated round spermatids.

Localization of mRNAs by in-situ hybridization to the residual body at stages IX-X of the cycle of the rat seminiferous epithelium: fact or artefact?

Several recent articles have reported localization of specific mRNAs in the rat testis to stage IX and X seminiferous tubules using in-situ hybridization. In all cases the expression was located basally in the tubules and appeared as discrete round clusters of grains close to the lamina propria. The localization was interpreted as being in Sertoli cells or leptotene spermatocytes.

CONTROL OF SEX RATIOS IN HAPLOID POPULATIONS OF THE MOSS, CERATODON PURPUREUS.

Female biased sex ratios occur in a number of unrelated mosses. Such ratios refer to the relative numbers of male and female gametophytes in moss populations and are therefore more comparable to the numbers of pollen grains and ovules in populations of seed plants than to the numbers of male (microsporangiate) and female (megasporangiate) sporophytes. A survey of 11 populations of the moss, Ceratodon purpureus, showed that sex ratios are heterogeneous, but that female biases occur in more than half the populations.