Phosphatidylinositol-specific phospholipase C activity as a marker to distinguish between pathogenic and nonpathogenic Listeria species.

In this study, 468 Listeria strains were checked for the presence of phosphatidylinositol-specific phospholipase C (PI-PLC) activity by using a simple assay that consisted of overlaying colonies formed on agar plates with L-alpha-phosphatidylinositol as substrate. In this assay, PI-PLC-active colonies show turbid halos around the colonies as a result of the release of insoluble diacylglycerol from the substrate. This activity was detected only in the pathogenic species Listeria monocytogenes and was not present in any of the 167 strains of Listeria seeligeri, Listeria welshimeri, Listeria innocua, Listeria murrayi, and Listeria grayi tested. Hence, screening for PI-PLC activity permits discrimination between pathogenic and nonpathogenic Listeria species. In particular, the hemolytic but nonpathogenic species L. seeligeri can now be separated from the hemolytic and pathogenic species L. monocytogenes and L. ivanovii. The use of this assay will improve the specific detection and/or isolation of pathogenic Listeria species from clinical samples or food enrichment cultures.     

A new variant glyoxalase I allele that is readily detectable in stimulated lymphocytes and lymphoblastoid cell lines but not in circulating lymphocytes or erythrocytes

We describe an allele of the human glyoxalase GLO locus that encodes an enzymatically inactive form of the protein, which would not have been detected if only circulating erythrocytes and lymphocytes had been studied. The new allele is named GLO*3 and its protein product, GLO 3. Circulating blood cells of GLO*2/GLO*3 heterozygotes have just one electrophoretic band that migrates as the normal 2-2 dimer. Lymphoblastoid cell lines and phytohemagglutinin-stimulated lymphocytes from the same individuals have two electrophoretic bands, one with the mobility of the 2-2 dimer and one with the mobility of the 2-1 dimer that is present in GLO*2/GLO*1 heterozygotes, but a band with the mobility of the 1-1 dimer is not present. Therefore, the GLO*3 allele encodes a monomer that has the electrophoretic mobility of GLO 1 but is enzymatically inactive unless it is combined with normal monomers in 2-3 and 1-3 heterodimers. The failure to detect the GLO 3 protein in red cells and unstimulated lymphocytes is attributed to a relatively great instability or small rate of production in those cells. Consistent with this interpretation is the reduction of GLO activity in red cells of GLO*2/GLO*3 and GLO*1/GLO*3 heterozygotes to 65% or less of that in normal homozygotes and heterozygotes, while the activity of GLO*3 heterozygous lymphoblastoid cells is about 80% of normal. In contrast, the GLO activity of lymphoblastoid cells that had one copy of the GLO locus deleted by γ-irradiation was 50%–60% of normal. Our observations indicate that certain kinds of mutant alleles of the GLO locus, and perhaps other loci, may not be detected in electrophoretic surveys on circulating blood cells only. The segregation of alleles that are not expressed in circulating red and white blood cells could confuse attempts to determine parentage, as they might have in the family described here. The observations also demonstrate the feasibility of mapping human genes by using ionizing radiation to create partial chromosome deletions in cultured cells.     

Evidence for Glucocorticoid Target Cells in the Rat Optic Nerve. Hormone Binding and Glycerolphosphate Dehydrogenase Induction

Abstract: Biochemical evidence suggests that neuroglia are responsive to glucocorticoids, yet previous studies of glucocorticoid localization have typically failed to demonstrate significant uptake by neuroglial cells. To further investigate this problem, we measured glycerol-3-phosphate dehydrogenase (GPDH) activity and glucocorticoid receptor binding capacity in normal rat optic nerves and in those undergoing Wallerian (axonal) degeneration. Binding studies were also performed on hippocampus and anterior pituitary for comparison purposes. Normal optic nerve preparations possessed a high level of GPDH activity that was glucocorticoid-inducible and that increased further following axonal degeneration. Antibody inactivation experiments demonstrated the presence of more enzyme molecules in the degenerating nerve preparations. Correlative immunocytochemical studies found GPDH-positive reaction product only in morphologically identified oligodendrocytes, a result that is consistent with the previously reported localization of this enzyme in rat brain. Optic nerve cytosol fractions displayed substantial high-affinity binding of both dexamethasone (DEX) and corticosterone (CORT) that, like GPDH, was elevated approximately twofold in degenerating nerves. Finally, in vivo accumulation of [³H]DEX and [³H]CORT by optic nerve and other myelinated tracts was examined using nuclear isolation and autoradiographic methods. Although neither steroid was found to be heavily concentrated by these tissues in vivo , a small preference for DEX was observed in the nuclear uptake experiments. These results are discussed in terms of the hypothesis that glial cells are targets for glucocorticoid hormones.     

EFFECTS OF ICE ON ASCOPHYLLUM NODOSUM WITHIN THE GREAT BAY ESTUARY SYSTEM OF NEW HAMPSHIRE-MAINE12

The, effects of ice on Ascophyllum nodosum (L.) Le Jolis within the Great Bay Estuary System of New Hampshire-Maine, U.S.A. were assessed during the winter of 1980–81. Approximately 50% of the plants late fall standing crop, or an estimated 136 tonnes dry weight, was removed by ice-rafting. Pieces of Ascophyllum removed averaged 22 cm in length, 15 g in fresh weight and generally represented 2–3 years of growth. Although the winter of 1980–81 wax somewhat extreme, a similar pruning process probably occurs each year contributing to the characteristic bushy habit of attached inner estuarine plants. Ascophyllum fragments rafted in ice and deposited into salt marshes are suggested as a major source of the, ecad scorpioides (Hornemann) Hauck.     

Diterpene carboxylic acids and a heliangolide from Helianthus angustifolius

Two diterpene carboxylic acids, one a new kaurenoid derivative and one the previously characterized labdane, ()-cis-ozic acid, as well as a     

Effect of hormones on growth rates of malignant and nonmalignant human mammary epithelia in cell culture

Summary The individual effects of seven hormones on the in vitro growth rate of different classifications of human mammary epithelium were compared. Hormones used were: 17β-estradiol, estriol, progesterone, hydrocortisone, testosterone, prolactin, and growth hormone. Cell cultures included three established breast cell lines and primary monolayer cultures established form breast fluids and excised mammary tissue from 40 women and 4 men. Specimens comprised three classifications: normal, nonmalignant atypical, and malignant. Growth was quantitated in situ and expressed as population doubling time. Principal findings were: (a) estrogens, prolactin, and growth hormone stimulated growth of normal cells more frequently than growth of malignant cells, whereas testosterone and hydrocortisone stimulated growth of malignant cells more frequently than growth of normal cells; (b) cells cultured from nonmalignant atypias generally showed hormone response profiles intermediate between those of normal and malignant cells; (c) progesterone stimulated the growth of cells from malignant specimens but not the growth of cells from normal and nonmalignant atypical samples. This research was supported by NIAID Research Training Grant 5-TO1-A1-00332-06.     

The early ontogeny of hematopoietic cells studied by grafting cytogenetically labeled tissue anlagen: Localization of a prospective stem cell compartment

The relative contributions of ventral blood island mesoderm and dorsal anterior mesoderm to differentiated lineages of hematopoietic cells was assessed by reciprocal grafting of cytogenetically labeled tissues between 67- and 72-hr-old frog embryos (Shumway stages 15–16). Diploid (2N) and triploid (3N) cell populations from hematopoietic organs were distinguished by Feulgen-DNA microdensitometric analysis. Ventral blood island mesoderm appears to contribute an embryonic erythrocyte population that progressively declines during larval development. Dorsal anterior mesoderm appears to contribute a population of precursor cells that gives rise to differentiated lineages of hematopoietic cells found in the thymus, pronephros, mesonephros, spleen, and blood. Histological examination of the developing dorsal anterior area indicates that extensive vascularization is a prominent characteristic of this region. The dorsal aortae and vasculature surrounding the pronephros may be sites where at least one population of hematopoietic cells matures and subsequently enters circulation.     

Structural studies of the capsular antigen of haemophilus infuenzae type c

The structure of the capsular antigen from Haemophilus influenza type c has been investigated, n.m.r. spectroscopy being the principal method used. It is concluded that the antigen is composed of repeating-units having the following structure:

O-Acetyl groups are present in ～90% of the repeating-units.     

The role of cell membrane in the antiviral effect of interferon

The mechanism of interferon action in human fibroblasts has been studied by use of both antisera to human fibroblast interferon and the antisera to the surface of human fibroblast cell. The anti-interferon serum completely neutralized the antiviral effect of human fibroblast interferon. Interferon antiserum prevented the intracellular antiviral state from developing when added to the medium of the cells in which interferon synthesis had already been induced by poly (I · C). This suggests that development of the antiviral state involves interferon interaction with the external part of the producing cell. Treatment with the serum directed against the surface of human fibroblast cells failed to inhibit the antiviral activity of human interferon in these cells. In addition, the effect of gangliosides on the antiviral activity of human interferon was studied and it was found that human interferon binds to gangliosides and that this interaction leads to inactivation of the antiviral effect of interferon. Pretreatment of human fibroblasts with gangliosides had no effect on the sensitivity of these cells to exogenous interferon.