Current Microbiology

Altwegg, Martin; Graevenitz, Alexander; Zollinger-Iten, Jaqueline

doi: 10.1007/BF01577204pmid: N/A

Decarboxylase/dihydrolase activities inAeromonas spp. are important as diagnostic tools and indicators of enterotoxin production. We have analyzed the following media at 25°C, 29°C, and 37°C, respectively, for their ability to detect such activities: Møller's, Falkow's, and Fay and Barry's (F&B) containing ornithine, lysine, and arginine, respectively, as well as motility-indole-ornithine (MIO) medium and lysine decarboxylase broth with 0.1% agar (LDC). In order to retain ornithine negativity, but to get as much positivity as possible for arginine, optimal incubation conditions were 29°C for 96 h (Møller), 48 h (Falkow, MIO, and LDC), and 24 h (F&B). The F&B medium proved to be the most sensitive for the detection of lysine decarboxylase, a positive test being highly correlated with the two speciesA. hydrophila andA. sobria, and we suggest its use for routine detection of decarboxylase/dihydrolase activities.

Gauthier, Michel; Munro, Patrick; Mohajer, Soussan

doi: 10.1007/BF01577205pmid: N/A

The objective of this study was to evaluate the influence of seawater salts, and more specially sodium chloride, on the recovery ofEscherichia coli cells after exposure to natural seawater in laboratory microcosms, and the possible adaptation in this bacterium to high salinity. The recovery efficiency of a complex organic medium supplemented with sodium chloride largely depended on the strain and varied with starvation time and salinity. Moreover, cells previously grown on salted medium appeared more able to survive after exposure to seawater. It is assumed that, withinE. coli populations, some cells are able to adapt to seawater in the presence of both salts and organic matter.

Appanna, Vasu; Szczepan, Edward; Viswanatha, Thammaiah

doi: 10.1007/BF01577206pmid: N/A

Supplementation of cultures ofAerobacter aerogenes 62-1, 43/4 h after initiation of growth withd-glucose (20 mM), resulted in a threefold increase in the production of aerobactin. Administration ofl-lysine under similar conditions led to a twofold incrasse in the yield of the siderophore. Studies with a cell-free system ofAerobacter aerogenes 62-1 revealed considerable stimulation of lysine-N6-hydroxylase activity by glucose and several of its derivatives. Inclusion of ferric chloride (0.1 mM) in the growth medium led to the repression of both lysine-N6-hydroxylase and aerobactin synthetase.

Khoury, Peter; Lombardi, Steve; Slepecky, Ralph

doi: 10.1007/BF01577207pmid: N/A

Spores ofBacillus megaterium, B. subtilis, andB. stearothermophilus, harvested from cultures grown and sporulated at different temperatures or in the presence of ethanol, had different thermal resistance. There was a direct relationship between the sporulation temperature and the spore-killing temperature. The spores were more temperature-sensitive when formed in ethanol-supplemented media. Temperature and ethanol are known to perturb the degree of order within membranes and to alter membrane functions. Thus, alteration of spore membranes is an additional factor in the multifactorial nature of heat resistance. Another interpretation may be that heat shock proteins, known to be induced by heat, are formed during sporulation and may increase the thermostability of the spores.

Cheung, Peter; Buster, Dan; Hammock, Bruce

doi: 10.1007/BF01577208pmid: N/A

A 25,000-dalton cytolytic protein was isolated from the parasporal crystal ofBacillus thuringiensis subsp.israelensis. Hemolytic activity of this protein decreased with increasing pHs and was totally inhibited at pH 10.0. No mosquito larvacidal activity was observed with this protein either in the solubilized form or when the protein was adsorbed to latex beads.

Pall, Martin; Robertson, Carla

doi: 10.1007/BF01577209pmid: N/A

Several saturated, monosaturated, and polyunsaturated fatty acids produce rapid increases in cyclic AMP levels in the fungusNeurospora crassa when added to the growth medium at 10–50 μM. The time courses of cyclic AMP increase resembled those previously shown to be induced by other agents, reaching peak cyclic AMP levels at about 2 min after fatty acid addition. These fatty acids had little or no influence on adenylate cyclase fromNeurospora crassa in vitro. On the basis of previous evidence that uncouplers of oxidative phosphorylation increase cyclic AMP levels and that fatty acids can act as uncouplers, we suggest that the fatty acids in vivo may act to increase cyclic AMP levels by acting as uncouplers of oxidative phosphorylation. In agreement with this suggestion, two fatty acids were shown to produce decreased ATP-ADP ratios inNeurospora at concentrations producing cyclic AMP increases.

Grobbelaar, Nathanaël; Lin, Hung-Yun; Huang, Tan-Chi

doi: 10.1007/BF01577210pmid: N/A

All oxygen levels are detrimental to the nitrogenase activity ofSynechococcus RF-1 cells. In continuous light, cultures maintain a high dissolved oxygen concentration and a continuous but usually low rate of nitrogenase activity.

Friedman, Herman; Widen, Raymond; Newton, Catherine; Klein, Thomas

doi: 10.1007/BF01577211pmid: N/A

Legionella pneumophila, the etiologic agent of respiratory pneumonia and systemic infections of man and some experimental animals, was studied in regard to the ability of these bacteria to induce blastogenic responses by spleen cells from normal vs sensitized mice. Antigens from this organism, including whole cell vaccine, an outer membrane extract, and a purified lipopolysaccharide-rich antigen, induced blastogenesis of normal spleen cells with peak responses on day +3 in vitro, similar to the blastogenic responses of spleen cells from the same animals exposed to the plant mitogens phytohemagglutinin and Concanavalin A, or the nonspecific bacterial antigenEscherichia lipopolysaccharides coli (LPS). Spleen cells from mice vaccinated with killedLegionella or infected with a sublethal dose of these bacteria 3–4 weeks or more previously evinced increased blastogenic responses to theLegionella antigens but not to the nonspecific mitogens or theE. coli LPS. The spleen cells from legionellae-sensitized mice evinced not only heightened blastogenic responses on day +3 of culture but also heightened responses during day +5 of culture. Spleen cells from sensitized mice showed less responses to the nonspecific plant mitogens orE. coli LPS on day +5 of culture. These results support the view that, after sensitization of mice with a bacterial antigen such asL. pneumophila, spleen cells respond in a specific heightened blastogenic manner toLegionella antigen, and this response has a higher magnitude and is more prolonged than the non-specific responses of cells from normal mice.

Hayashi, Sachio; Cho, Tamaki; Kaminishi, Hidenori; Hagihara, Yoshisato; Watanabe, Kenji

doi: 10.1007/BF01577212pmid: N/A

The metabolism ofl-proline toN-acetyl-d-glucosamine (GlcNAc) during germ tube formation ofCandida albicans (C. albicans) ATCC 1002 was studied. In uptake experiments, 6.9 nmol ofl-[14C]proline were taken up by 1×106 cells during 3 h of incubation at 37°C. The percentage of germ tube formation was 94 under the same condition. The presence of GlcNAc reduced the uptake ofl-proline to 3.0 nmol. The percentage of germ tube formation was 95 in the presence and absence of GlcNAc. The [3H]GlcNAc uptake was 3.0 nmol and was constant whetherl-proline was present or not. After the preparation of a chitin fraction from germ tubes that were labeled withl-[14C]proline, the radioactivity froml-proline was detected in the glucosamine (GlcN) fraction by thin-layer chromatography (TLC). The metabolism ofl-proline to GlcNAc in chitin during germ tube formation was confirmed in this experiment.

Yunker, Conrad; Tully, Joseph; Cory, Jack

doi: 10.1007/BF01577213pmid: N/A

The ability of several continuous tick cell culture lines to support growth of tickborne spiroplasmas (helical, wall-less prokaryotes in the classMollicutes) was assessed. Seven triturates, prepared from pools ofIxodes pacificus ticks naturally infected with theSpiroplasma sp. (group VI) organism, were retrieved from frozen (−70°C) storage and passaged in three distinct tick cell lines, in antibiotic-free tick cell culture medium alone, or in spiroplasma culture medium (SP-4 formulation). Six spiroplasma strains were recovered in the RML-19 cell line fromDermacentor variabilis, and five isolations were made in another cell line (RML-15) from this tick species. None was recovered in aRhipicephalus sanguineus cell line (RML-23), in tick cell culture medium, or in SP-4 broth medium. One of the spiroplasma isolates (Y43) was maintained through four consecutive weekly refeedings of theD. variabilis cell line and for three feedings ofR. sanguineus cells, where numbers of spiroplasmas in cell supernatants reached levels comparable to those obtained in the SP-4 medium.