Transforming growth factor beta induces the production of interleukin 6 by human peripheral blood mononuclear cells

Previous studies have indicated that the cytokine transforming growth factor beta 1 (TGF beta 1) has immunosuppressive properties and can inhibit the production of tumor necrosis factor (TNF) and Interleukin 1 (IL 1) by human peripheral blood mononuclear cells. In this study, we have examined the effects of TGF beta 1 on the production of Interleukin 6 (IL 6) by human peripheral blood mononuclear cells. Treatment with only TGF beta 1 leads to the induction of IL 6, and this was both dose- and time-dependent. The effect of TGF beta 1 was evident at the level of IL 6 mRNA, suggesting TGF beta 1-induced de novo synthesis of IL 6. Induction of IL 6 by TGF beta 1 was specific, as other cytokines made by mononuclear cells (TNF and IL 1) were not induced by TGF beta 1. Furthermore, when a panel of stimuli were compared for their ability to induce IL 1, TNF and IL 6 in the presence or absence of TGF beta 1, IL 6 levels were augmented in the presence of TGF beta 1, while the induction of IL 1 and TNF was inhibited significantly. These results indicate that TGF beta 1 has complex effects on the production of cytokines by peripheral blood mononuclear cells and that TGF beta 1 is not inhibitory for all cytokine production. The ability of TGF beta 1 to induce IL 6 suggests that IL 6 may mediate some of the effects of TGF beta 1.     

The XcpR protein of Pseudomonas aeruginosa dimerizes via its N-terminus

Extracellular protein secretion by the main terminal branch of the general secretory pathway in Pseudomonas aeruginosa requires a secretion machinery comprising the products of at least 12 genes. One of the components of this machinery, the XcpR protein, belongs to a large family of related proteins distinguished by the presence of a highly conserved nucleotide binding domain (Walker box A). The XcpR protein is essential for the process of extracellular secretion and amino acid substitutions within the Walker A sequence result in inactive XcpR. The same mutations exert a dominant negative effect on protein secretion when expressed in wild-type bacteria. Transdominance of XcpR mutants suggests that this protein is involved in interactions with other components of the secretion machinery or that it functions as a multimer. In this study, the amino-terminal portion of the cI repressor protein of phage λ was used as a reporter of dimerization in Escherichia coli following fusion to full-length as well as a truncated form of XcpR. The cI–XcpR hybrid proteins were able to dimerize, as demonstrated by the immunity of bacteria expressing them to killing by λ phage. The full-length XcpR as well as several deletion mutants of XcpR were able to disrupt the dimerization of the chimeric cI–XcpR protein. The disruption of cI–XcpR dimers using the deletion mutants of XcpR, combined with the analysis of their dominant negative effects on protein secretion, was used to map the minimal dimerization domain of XcpR, which is located within an 85 amino acid region in its N-terminal domain. Taken together, the data presented in this paper suggest that the XcpR protein dimerizes via its N-terminus and that this dimerization is essential for extracellular protein secretion.     

Proliferation and differentiation of chick skeletal muscle cells cultured in a chemically defined medium

By using the technique of nuclear transplantation in Paramecium [1], amicronucleate and renucleate clones were prepared in P. caudatum. The major differences between amicronucleate and micronucleate cells in the vegetative stage are elongation of cell cycle time, decrease in food vacuole formation, and shortening of the buccal cavity in the amicronucleate cells. These characteristics of amicronucleate cells are closely related with the absence of micronucleus, because all of these abnormalities were cured when the micronucleus was transplanted again into the amicronucleate. It is evident that the germinal micronucleus plays an important role not only during the sexual cycle but also in vegetative growth. Elongation of the cell cycle time in amicronucleates was also observed in P. bursaria and P. jenningsi.     

The presence or absence of light during flotation restricted environmental stimulation: Effects on plasma cortisol,blood pressure,and mood

This study examined the effect of light on relaxation associated with flotation restricted environmental stimulation therapy (REST), as measured by plasma cortisol, mean arterial pressure, and psychometric parameters. Twenty-one subjects were paired by baseline cortisol levels into two groups: one experiencing flotation REST in the presence of light (REST-L) and one experiencing flotation REST in the absence of light (REST-D). Subjects were 15 male and 6 female students aged 22–28 in normal health who had not experienced REST. Repeated flotation REST (8 sessions) either with light or without light was associated with a decrease in plasma cortisol and a decrease in mean arterial pressure, with no differences in effectiveness between groups. The psychometric assessment of mood, using the POMS scale, before and after sessions 1 and 8 revealed mood state improvement in both REST-L and REST-D groups. These data suggest that the presence of light did not compromise the flotation REST experience, as evidenced by the lack of difference between REST-L and REST-D groups.     

Modelling ultraviolet exposures in a school environment.

A technique has been developed to represent erythemally effective ultraviolet radiation exposure within a school environment. The technique models the erythemally effective exposure onto a horizontal plane representation of a mapped school environment located in Hervey Bay (25 degrees S, 153 degrees E), Australia. The input parameters used to model the ultraviolet exposures received within the school playground included the measured sky view, ground albedo and standing surface albedo. Estimates of the erythemally effective ultraviolet exposure received within the school playground during morning tea and lunch time meal breaks during a winter and summer school day are presented. The influence of tree shade and building structure was found to vary significantly with solar zenith angle modelled over the winter and summer school meal break times with horizontal plane exposures predicted to vary from between 0 and 7 SED at different locations within the playground. The technique presented provides a method that can be followed to examine the effect of surrounding buildings and surface structures of real environments on the predicted horizontal plane ultraviolet exposure.     

Multipoint linkage analysis of the short arm of chromosome 11 in non-insulin dependent diabetes including maturity onset diabetes of youth

Summary Members of three families with maturity onset diabetes of youth (MODY) and seven with common type 2 diabetes were typed for six DNA markers (H-RAS, INS, HBBC, PTH, CALC1, CAT) on the short arm of chromosome 11. Using conventional pairwise linkage analysis, close linkage in the MODY families was excluded for all six markers. By multipoint analysis and a genetic map of the short arm of chromosome 11, MODY was excluded from a region of at least 35 and up to 60 centiMorgans (cM) on the short arm of chromosome 11. Multipoint analysis in the type 2 families also excludes linkage to the INS, H-RAS region of at least 3 and up to 30 cM. This study using multipoint linkage analysis in non-insulin dependent diabetes provides strong evidence against a role for mutations in or around the insulin gene in the causation of MODY or type 2 diabetes in the families studied.     

Effect of nitrogen form on the growth and nitrate concentration of lettuce

Summary A pot experiment with lettuce involving three N forms each at six application levels, showed that lettuce can be grown satisfactorily with a very low nitrate content when supplied with ammonium sulphate and a nitrification inhibitor. For plants growing on nitrate N, the optimum midrib sap nitrate concentration as maturity approached was about 1400 mg/1 NO₃-N. Large losses of mineral N were observed from the peat medium, even in the absence of plants. A relationship is presented which would enable a lettuce grower to estimate whole-shoot nitrate concentration from a quick test of midrib sapi.e. NO₃-N (mg/kg in fresh shoot) =0.14×NO₃-N (mg/l in sap). Tipburn was worst at intermediate levels of applied N, and was less serious with pure ammonium nutrition than with nitrate.     

B lymphocyte receptors and polyphosphoinositide degradation

Resting B lymphocytes can be activated and induced to proliferate by antibodies against their antigen receptors (anti-lg). We demonstrate an early increase in the level of [3H]inositol trisphosphate in [3H]inositol-labeled murine B cells, which suggests breakdown of phosphatidylinositol bisphosphate by phospholipase C. In line with this, the level of [3H]1,2-diacylglycerol was also elevated after incubation of [3H]arachidonic-acid-labeled B cells with anti-Ig. Anti-lg also caused a rapid increase in the level of cytosolic Ca2+ in B cells. In contrast, two other polyclonal B cell activators, lipopolysaccharide and phorbol myristate acetate, failed to induce any of these effects. Our results suggest that anti-lg may induce B cell growth via phosphoinositide degradation and Ca2+ mobilization, and that phorbol myristate acetate, and possibly lipopolysaccharide, bypass these initial events.     

Revision ofVerbesina sect.Pseudomontanoa (Asteraceae)

Verbesina sect.Pseudomontanoa is revised. The last treatment of the group byRobinson & Greenman (1899) recognized 5 species; the present treatment recognizes 12 species, 3 of which (V. breedlovei, V. cronquistii andV. olsenii) are described as new. A key to species, phyletic diagram and distribution maps are provided.