Cytokine production after intravenous or peritoneal gram-negative bacterial challenge in mice. Comparative protective efficacy of antibodies to tumor necrosis factor-alpha and to lipopolysaccharide.

The production of TNF-alpha, IL-1, and IL-6 was measured in mice after bolus i.v. Escherichia coli O111 LPS injections and during bacteremia induced either by bolus i.v. or by i.p. challenges of live E. coli O111. High but transient TNF-alpha peaks were observed after bolus i.v. LPS or bacterial challenges. In contrast, the levels during lethal peritonitis increased progressively to values 50- to 100-fold lower than the peak values observed after i.v. injections, and remained sustained until death. Whereas after i.v. challenge with 1000 LD50 of LPS, anti-TNF-alpha antibody fully protected mice from death and reduced serum IL-1 and IL-6 levels, anti-TNF-alpha antibody did not improve the survival of mice nor reduced serum IL-1 and IL-6 levels after i.p. bacterial challenge. In contrast to anti-TNF-alpha antibodies, anti-LPS antibodies were protective in the peritonitis model. Protection was accompanied by a striking reduction of bacterial numbers and of TNF-alpha, IL-1, and IL-6 levels in the serum, but the levels of these cytokines were only marginally affected in the peritoneal lavage fluid. This latter observation demonstrates that the local peritoneal cytokines did not diffuse readily into the circulation, thus suggesting that at least part of the circulating cytokines are produced systemically. In conclusion, the striking differences between cytokine profiles as well as the divergent efficacy of anti-TNF-alpha antibody after i.v. bolus and after i.p. challenges suggest that TNF-alpha may not be as important in the pathogenesis of lethal peritonitis than after lethal acute bacteremia.     

Auxin-induced H+-pump stimulation does not depend on the presence of epidermal cells in corn coleoptiles

Cell-wall acidification and electrical reactions (depolarization and hyperpolarization) are typical auxin responses in maize (Zea mays L.) coleoptiles. In an attempt to test the role of the outer epidermis in these responses, they have been measured and compared in intact and peeled coleoptile fragments. To exclude interactions between parenchymal and epidermal cells, the coleoptile pieces were completely stripped of their outer epidermis. This preparation was monitored by means of a scanning electron microscope. When externally applied indole-3-acetic acid was tested, we found that neither cell-wall acidification nor the electrical membrane responses depended on the presence of intact epidermal cells.Abbreviations IAA Indole-3-acetic acid - MES 2-[N morpholino-ethane-sulfonic acid - TRIS 2-Amino-2-hydroxymethyl-1,3-propanediol We thank Kuki Kaethner for her excellent technical assistance. This work was supported by the Hessische Graduiertenförderung and the Deutsche Forschungsgemeinschaft.     

Relationships between take-all,soil conduciveness to the disease,populations of fluorescent pseudomonads and nitrogen fertilizers

Take-all of wheat, caused by Gaeumannomyces graminis var tritici (Ggt), is reduced by ammoniacal fertilizers as compared to nitrate sources. This influence of nitrogen on the disease is only observed on nodal roots at flowering. But soil conduciveness to take-all, as measured in a soil bioassay, is modified earlier. Forty days after nitrogen application at early tillering, the NH₄-treated soil became less conducive than the NO₃-treated one. When nitrogen applications are done at sowing and at tillering, differences in disease propagation between the two soils are enhanced. Results from four years of experimentation show that when the level of natural soil inoculum is high, disease severity is reduced by ammonium, showing an effect on the parasitic phase of Ggt. At a low level of natural inoculum the effect of the source of nitrogen is mainly observed on the percent of infected plants, indicating that the saprophytic and preparasitic phases are affected. Rhizospheric bacterial populations increase from sowing to tillering, but differences on take-all conduciveness after tillering are not correlated with differences in the amounts of aerobic bacteria or fluorescent pseudomonads isolated from soils treated with different sources of nitrogen. Qualitative changes in fluorescent Pseudomonas spp. populations, like in vitro antagonism, are more likely to explain differences in soil conduciveness to take-all than are quantitative changes in this group. Nevertheless, the introduction of Ggt in a cropped soil leads to a greater increase in fluorescent pseudomonads populations than in total aerobic bacteria.The delay between reducing soil conduciveness and reducing disease in the field with ammonium nitrogen fertilization, the qualitative change of fluorescent pseudomonads populations and the role of necroses in rhizobacteria multiplication, provide information leading to our representation of a dynamic model based on the differentiation of the wheat root system into seminal and nodal roots.     

Selenium and blood pressure studies in young and adult normotensive,renal, and spontaneously hypertensive animals

With reports of either no change or reduction of blood pressure, the relationship between selenium and blood pressure has not been clear. Normal Se values are not available for the Sprague Dawley (SD) rat or in the young and adult rat with various models of experimental hypertension. This study measured serum Se levels in the young and adult normotensive (NT), Grollman renal hypertensive (RH), and Okamoto-Aoki spontaneous hypertensive rats (SHR). The young animals have statistically significant (P<0.001) lower Se values as measured by the fluorometric method than those found at adulthood. Selenium levels were found to be altered in the adult SHR animals when compared with the RH and NT animals. The serum Se value for the normotensive SD rat was found to be 65.0±3.5 μg/dL, and for the two experimental models, 63.7±4.6 μg/dL for the RH, whereas the SHR level was elevated to 75.04±4.8 μg/dL (P<0.001). Elevated serum Se values in the adult SHR animals suggests an altered metabolism in SHR animals.     

Sequence analysis of WIS-2-1A,a retrotransposon-like element from wheat

WIS-2-1A, a 8624 bp insertion in the Glu-1A-2 locus of chromosome 1A of wheat, consists of two 1755 bp long terminal repeats enclosing a 5114 bp internal region. No long open reading frames could be found, but inspection of the predicted amino acid sequence showed regions with homology to retrotransposon structures, including a methionine tRNA initiator binding site, a nucleotide binding domain, a protease, an integrase and a polymerase. DNA replication errors have resulted in frame-shifts in the protein coding region, suggesting that retrotransposition of WIS-2-1A, if it occurs, must be mediated by trans-acting factors.     

Production and standing stocks of the kelp Macrocystis laevis Hay at the Prince Edward Islands,Subantarctic

Summary The recently described species Macrocystis laevis Hay is endemic to the Prince Edward Islands. Aerial photographs of Marion Island were used to outline the distribution of the kelp and to assess its cover. M. laevis occurs along the lee shore of the island, between the 5 and 20 m isobaths. Plant densities and gross plant morphology were measured by divers during April/May 1988. Net production was estimated from growth measurements taken in April/May 1988 and 1989 and again during August 1989. The mean biomass of kelp was 0.67 kgC·m^–2 within the kelp beds. Net production was estimated at 7.7 gC·m^–2·d^–1 and 11.5 gC·m^–2d^–1 during the months of April and August respectively. M. laevis had a uniform frond-length frequency distribution, which suggests that only the oldest fronds are lost by wave action or senescence. Based on calculations for M. laevis and Durvillaea antarctica (the two species making up most of the macrophyte biomass) macrophytes are more productive per unit area than the phytoplankton but contribute less to the seas around the Prince Edward Islands by virtue of their small spatial coverage. Neither of the kelps lose much material as particulate or dissolved organic carbon through fragmentation. The extent of grazing on live M. laevis fronds is unknown, and only D. antarctica contributes to a macrofaunal detrital community. The contribution of M. laevis production to the nearshore ecology of the islands seems limited, as we suspect that almost all of its production is exported to the open ocean pelagic system.     

Analysis of nuclear sugar-binding components in undifferentiated and in vitro differentiated human promyelocytic leukemia cells (HL60)

The nuclear sugar-binding components (i.e., lectinlike molecules) were analyzed using isolated and membrane-depleted nuclei after incubation in the presence of fluorescein-labeled neoglycoproteins. This analysis was performed before and during the in vitro differentiation of HL60 cells into monocytes by PMA treatment and into granulocytes by DMSO treatment. The nucleoli of undifferentiated and differentiated HL60 cells were not labeled, unlike the nucleoli of other mammalian cells studied so far. This peculiarity allowed us to quantitatively analyze by flow cytometry the changes in the lectin activity associated with the extranucleolar territories enriched in ribonucleoprotein complexes. The neoglycoprotein binding was found to be significantly lower in differentiated than in undifferentiated cells. The decrease in neoglycoprotein binding was observed within the first 24 h of DMSO or PMA treatment, just before the arrest of DNA synthesis. Taking into account that the granulocytic differentiation required 72 h of chemical treatment, the extra-nucleolar lectins might be involved in modulation of the DNA synthesis rather than in phenotypic differentiation. These data are discussed in an attempt to reconcile the association of lectins with RNP complexes and their possible involvement in modulation of HL60 cell proliferation.     

Analysis of nuclear sugar-binding components in undifferentiated and in vitro differentiated human promyelocytic leukemia cells (HL60)

The nuclear sugar-binding components (i.e., lectin-like molecules) were analyzed using isolated and membrane-depleted nuclei after incubation in the presence of fluorescein-labeled neoglycoproteins. This analysis was performed before and during the in vitro differentiation of HL60 cells into monocytes by PMA treatment and into granulocytes by DMSO treatment. The nucleoli of undifferentiated and differentiated HL60 cells were not labeled, unlike the nucleoli of other mammalian cells studied so far. This peculiarity allowed us to quantitatively analyze by flow cytometry the changes in the lectin activity associated with the extranucleolar territories enriched in ribonucleoprotein complexes. The neoglycoprotein binding was found to be significantly lower in differentiated than in undifferentiated cells. The decrease in neoglycoprotein binding was observed within the first 24 h of DMSO or PMA treatment, just before the arrest of DNA synthesis. Taking into account that the granulocytic differentiation required 72 h of chemical treatment, the extra-nucleolar lectins might be involved in modulation of the DNA synthesis rather than in phenotypic differentiation. These data are discussed in an attempt to reconcile the association of lectins with RNP complexes and their possible involvement in modulation of HL60 cell proliferation.     

Effect of pH and butyrate concentration on the production of acetone and butanol by Clostridium acetobutylicum grown in continuous culture

Summary When Clostridium acetobutylicum was grown in continuous culture under glucose limitation at neutral pH and varying dilution rates the only fermentation products formed were acetate, butyrate, carbon dioxide and molecular hydrogen. The Y _glucose ^max and (Y _ATP ^max ) _gluc ^exp values were 48.3 and 23.8 dry weight/mol, respectively. Acetone and butanol were produced when the pH was decreased below 5.0 (optimum at pH 4.3). The addition of butyric acid (20 to 80 mM) to the medium with a pH of 4.3 resulted in a shift of the fermentation from acid, to solvent formation.A preliminary report of part of this work was presented at a symposium Trends in the Biology of Fermentations for Fuels and Chemicals held December 7–11, 1980, at Brookhaven National Laboratory, Upton, New York; Gottschalk and Bahl 1981