PCR derived cDNA clones for X-linked phosphoglycerate kinase-1 in a marsupial, the tammar wallaby (Macropus eugenii).

cDNA clones for the X-linked PGK-1 were obtained from a tammar wallaby liver by PCR and sequenced. The PGK-1 gene published here is the consensus sequence of those clones. The sequence represents an open reading frame of 1251 bp. Sequence comparisons to X-linked and autosomal sequences showed the greatest homology with the X-linked PGK-1 genes in eutherian species. This sequence opens the way for studying the paternal X inactivation phenomenon in marsupials and will assist in defining the time course of mammalian evolution.     

Recombinant interferon-alpha, -beta, and -gamma enhance the proliferative response of human B cells

Recombinant interferons (IFN-alpha, -beta, and -gamma) were examined for their effects on B cell activation. Relatively small IgM+ B cells from human blood samples were isolated by fluorescence-activated cell sorting and were used as target cells. Although the interferons themselves were nonmitogenic, each enhanced the proliferative response induced by a mitogenic anti-mu monoclonal antibody, with IFN-beta usually showing the greatest enhancement and IFN-gamma the least. Pretreatment with the interferons primed resting B cells to undergo enhanced DNA synthesis in response to the anti-mu antibody DA4. Conversely, anti-mu pretreatment, followed by IFN treatment, did not induce B cells to enter the S phase. Time-course analysis revealed that IFN could augment the anti-mu response even when added as late as the final 24 hr of a 3-day culture interval. Combinations of IFN-gamma plus IFN-alpha or -beta were synergistic in the anti-mu response, whereas the IFN-alpha plus IFN-beta combination was not. The data suggest that interferons produced by both lymphocytes (IFN-gamma) and nonlymphoid inflammatory cells (IFN-alpha and -beta) can enhance B cell growth via different mechanisms.     

Identification of Lotus Rhizobia by Direct DNA Hybridization of Crushed Root Nodules

Hybridization of crushed Lotus pedunculatus root nodules with ³²P-labeled total genomic DNA probes was used to identify Rhizobium loti and Bradyrhizobium sp. (Lotus rhizobia). Probes always hybridized with homologous target DNA and frequently with DNAs of other strains from the same genus. Intergeneric hybridization did not occur. Results were comparable to those from colony hybridization.     

C3 allotypes in pregnancy hypertension and eclampsia

C3 allotyping has been performed on 424 Australian women, 203 with normotensive pregnancies, 161 with hypertensive noneclamptic pregnancies and 60 eclamptic women. The frequency of women heterozygous for 'rare' C3 alleles was 1% in the normotensive women and 3.7% in the hypertensive group. Three out of 25 (12%) of the women with proteinuric hypertension in pregnancy carried 'rare' C3 alleles. This suggested the hypothesis that pre-eclampsia/eclampsia is associated with a higher frequency of rare alleles. The sample of 60 eclamptic women collected to test the hypothesis had no rare alleles, refuting the hypothesis. The frequency of the common (C3F, C3S) alleles did not differ significantly between the three groups. We conclude that there is no evidence for any association between susceptibility to eclampsia and allotypes of the C3 complement component.     

Human lymphocyte differentiation antigens HB-10 and HB-11. II. Differential production of B cell growth and differentiation factors by distinct helper T cell subpopulations

Two monoclonal antibodies (HB-10 and HB-11), which react with human T, B, and NK cells, identify approximately 50% of the Leu-3+ T helper (TH) cells in adult blood. In the present studies, the functional capabilities of the HB-11+ and HB-11-TH cell subpopulations were examined after purification by fluorescence-activated cell sorting. Both subpopulations proliferated in response to PHA, Con A, PWM, and OKT-3 antibodies. The HB-11+ TH cells gave a minimal proliferative response to soluble tetanus toxoid antigen, whereas HB-11-TH cells responded well. After mitogen activation, both HB-11+ and HB-11-TH cells and to produce soluble factors which induce large B cells to proliferate. However, PWM-stimulated HB-11+TH cells were incapable of inducing B cells to differentiate into antibody-secreting plasma cells, whereas HB-11-TH cells were efficient in this regard. The results suggest that the HB-11 antigen is expressed on a subpopulation of virgin TH cells that can produce B cell growth factors but are deficient in the ability to produce B cell differentiation factors.     

Condensed tannins deter feeding by browsing ruminants in a South African savanna

Summary The palatability of 14 species of woody plant was assessed for three species of browsing ruminant, namely kudus, impalas and goats. Results show that palatability was most clearly related to leaf contents of condensed tannins. The effect was a threshold one, with all plants containing more than 5% condensed tannins being rejected as food during the wet season period. In contrast palatability was not influenced by concentrations of protein-precipitating polyphenols, and only weakly related to contents of nitrogen, phosphorus, cations, fibre components and other secondary metabolites. Insect herbivory shows a different pattern. These findings support the hypotheses that (i) condensed tannins function to protect plant cell walls against microbial attack; (ii) hydrolyzable tannins function to inactivate the digestive enzymes of insect herbivores. Large mammalian herbivores are influenced by condensed tannins due to their dependance upon microbial fermentation of plant cell walls for part of their energy needs.     

Protein kinase C and an endogenous substrate associated with adenohypophyseal secretory granules.

Secretory granules isolated from anterior pituitary glands were examined for Ca2+/phospholipid-dependent protein kinase (protein kinase C) activity as well as the occurrence of granule-associated substrate proteins. Sheep adenohypophyses were fractionated by differential and sucrose-density-gradient centrifugation to yield a granule fraction enriched for luteinizing-hormone (lutropin)-containing secretory granules. Marker-enzyme analysis showed no detectable cytosolic contamination, although there were small amounts of plasma membranes (2-4%) and lysosomes (4-6%) associated with the preparation. As determined by histone-H1 phosphorylation after DEAE-cellulose DE-52 chromatography, protein kinase C activity with a marked dependence on Ca2+ and lipid (4-fold increase in their presence) was evident in the secretory-granule fraction. Phosphorylation in vitro of the secretory-granule fraction by endogenous and exogenous protein kinase C revealed a protein of Mr 36,000, which by two-dimensional SDS/polyacrylamide-gel electrophoresis showed multiple sites of phosphorylation. The Mr-36,000 protein was not found in cytosolic or plasma-membrane fractions and was not phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase. Several secretory-granule proteins served as substrates for the catalytic subunit, the most prominent of which were of Mr 63,000, 23,000 and 21,000. From these data, we suggest that phosphorylation of secretory-granule-associated proteins by protein kinase C and by cyclic AMP-dependent protein kinase may be important in secretion regulation in the anterior pituitary gland.     

Altered gene products are associated with activation of cellular rasK genes in human lung and colon carcinomas

Two lung and two colon carcinoma cell lines of human origin, which contained the same activated ras^K transforming gene, expressed abnormal species of p21 that were distinct from the p21 proteins expressed in normal human cells and other human carcinomas. The abnormal species of p21 expressed by three of these cell lines were indistinguishable from each other, but differed from the abnormal p21 expressed by one lung carcinoma cell line. NIH cells transformed by DNAs of these carcinomas expressed the same abnormal p21 species, indicating that these abnormal proteins were encoded by the activated ras^K genes detected by transfection. These results indicate that transforming activity of ras^K genes in human lung and colon carcinoma cell lines is activated by mutations which alter the structure of their gene products, and that activation of ras^K genes can result from different molecular alterations in different individual neoplasms.     

Chicken lens delta-crystallin gene expression and methylation in several non-lens tissues.

RNA sequences coding for the most abundant chicken lens proteins, delta-crystallin, were detected at very low levels in day old post hatch chick lung, heart, kidney and liver, and in 6 day embryo headless bodies. The pattern of cytosine methylation within the CCGG sequences of the delta-crystallin genes was also examined and shown to vary in several non-lens tissues, from several stages of development. Embryonic neural retina, which expresses a higher level of delta-crystallin RNA than the above tissues, is no less methylated in the sites studied than the tissues which have no association with the eye, and is actually more heavily methylated than the kidney. Thus no obvious correlation was found between undermethylation and gene expression.