Archiv für Mikrobiologie

Native Shewanella sp. RCRI7 is recently counted as an operative bacterium in the uranium bio-reduction. The aim of this study was to investigate the effects of uranium tolerance on the morphology and population of RCRI7, following its potential removal capacity in different time intervals. In this research, the bacterial growth and uranium removal kinetic were evaluated in aerobic TSB medium, uranium-reducing condition (URC), aerobic uranium-containing (AUC) and anaerobic uranium-free (AUF) solution, following evaluations of omcAB gene expressions. In addition, spectrophotometry analyses were performed in URC confirming the bio-reduction mechanism. It was found that the bacteria can grow efficiently in the presence of 0.5 mM uranium anaerobically, unlike AUC and AUF solutions. Since the bacterium's adsorption capacity is quickly saturated, it can be deduced that uranium reduction should be dominant as incubation times proceed up to 84 h in URC. In 92 h incubation, the adsorbed uranium containing unreduced and reduced (U (IV) monomeric), was released to the solution due to either increased pH or bacterial death. In AUC and AUF, improper conditions lead to the reduced bacterial size (coccus-shape formation) and increased bacterial aggregations; however, membrane vesicles produced by the bacteria avoid the uranium incrustation in AUC. In overall, this study implies that Shewanella sp. RCRI7 are well tolerated by uranium under anaerobic conditions and the amount of regenerated uranium increases over time in the reduced form.

Activities of enzymes of photosynthesis and photorespiration have been measured in extracts of vegetative cells and heterocysts from the filamentous cyanobacterium Anabaena cylindrica. Phosphoribulokinase, d-ribulose 1,5-bisphosphate carboxylase/oxygenase, phosphoglycollate phosphatase and glycollate dehydrogenase activities were readily measured in vegetative cell extracts, but were undetectable or negligible in heterocyst preparations. The data help to explain why heterocysts are unable to perform photosynthetic CO2 fixation. They also exemplify the co-ordinate compartmentation of enzymes of photosynthesis and photorespiration which occur in a differentiated phototrophic prokaryote.

The halophilic purple nonsulfur bacterium Rhodospirillum sodomense has been previously described as an obligate phototroph that requires yeast extract and a limited number of organic compounds for photoheterotrophic growth. In this work, we report on chemoheterotrophic growth of R. sodomense in media containing either acetate or succinate supplemented with 0.3–0.5% yeast extract. Plasma membranes isolated from cells grown aerobically in the dark contained three b-type and three c-type membrane-bound cytochromes with E m,7 of +171 ± 10, +62 ± 10 and –45 ± 13 mV (561–575 nm), and +268 ± 6, +137 ± 10 and –43 ± 12 mV (551–540 nm). A small amount of a soluble c-type cytochrome with a mol. mass of 15 kDa (E m,7≥ +150 mV) was identified. Spectroscopic and immunological methods excluded the presence of cytochrome of the c 2 class and high-potential iron-sulfur proteins. Inhibitory studies indicated that only 60–70% of the respiratory activity was blocked by low concentrations of cyanide, antimycin A, and myxothiazol (10, 0.1, and 0.2 μM, respectively). These results were interpreted to show that the oxidative electron transport chain of R. sodomense is branched, leads to a quinol oxidase that is fully blocked by 1 mM cyanide and that is involved in light-dependent oxygen reduction, and leads to a cytochrome c oxidase that is inhibited by 10 μM cyanide. These features taken together suggest that R. sodomense differs from the closely related species Rhodospirillum salinarum and from other species of the genus Rhodospirillum in that it contains multiple membrane-bound cytochromes c.

Die Bildung der Fortpflanzungsorgane erfolgt bei Mycosphaerella pinodes in drei Phasen. Auf eine Pyknidienphase folgt eine Pseudothecienphase, die schließlich von einer Chlamydosporenphase abgelöst wird. In der ersten, der Pyknidienphase, entstehen Pyknidien, die nacheinander das Stadium der Vorreife und Reife durchlaufen. In der zweiten, der Pseudothecienphase, bilden sich in zwei aufeinander folgenden Zeitabschnitten zunächst die äußeren sich auf der Substratoberfläche, dann die inneren sich auf den Pyknidien entwickelnden Pseudothecien. In der dritten, der Chlamydosporenphase, läßt sich eine Ausbreitungsphase von einer Vermehrungsphase trennen. Entscheidend wichtig scheint zu sein, daß die Bildung der Organe jeder Phase bereits in geringer konstanter Menge in der vorhergehenden Phase einsetzt.

Strain KYPW7T, isolated from the Funglin Stream in Taiwan, was characterized using a polyphasic taxonomy approach. Cells of strain KYPW7T were Gram-stain-negative, aerobic, non-spore forming, non-motile rods and formed white colonies. Growth occurred at 15–30 °C (optimum 25 °C), at pH 6–8 (optimum pH 6.5) and with 0–1% NaCl (optimum 0%). Phylogenetic analyses based on 16S rRNA and coding sequences of 92 protein clusters showed that strain KYPW7T represents a novel genus in the family Flavobacteriaceae. The 16S rRNA gene sequence of strain KYPW7T was related to the species of the genera Chryseobacterium (91.8–96.0% sequence similarity), Bergeyella (95.1–95.8%), Cloacibacterium (94.5–95.7%), Daejeonia (95.6%) and Riemerella (94.0–95.0%). Strain KYPW7T showed less than 72% average nucleotide identity and less than 24% digital DNA–DNA hybridization identity compared to the type strains of related genera within the family Flavobacteriaceae. The predominant fatty acids were iso-C15:0 and iso-C17:0 3-OH. The major isoprenoid quinone was MK-6 and the DNA G + C content was 36.8 mol%. The polar lipids had phosphatidylethanolamine, three uncharacterized aminophospholipids and an uncharacterized phospholipid. The polyamines contained homospermidine, putrescine and spermidine. On the basis of the genotypic and phenotypic data, strain KYPW7T represents a novel species of a new genus in the family Flavobacteriaceae, for which the name Amniculibacterium aquaticum gen. nov., sp. nov. is proposed. The type strain is KYPW7T (= BCRC 81123T = LMG 30598T = KCTC 62512T).

Sixty-eight strains of capnophilic fusiform Gram-negative rods from the human oral cavity were subjected to extensive physiologic characterization, tested for susceptibility to various antibiotics, and the mol-percent guanine plus cytosine of each isolate determined. The characteristics of the isolates were compared with 10 fresh and 2 stock isolates of Fusobacterium nucleatum. The isolates clearly differed from the Fusobacterium species on the basis of molpercent guanine plus cytosine, end products, growth in a capnophilic environment and fermentation of carbohydrates. All of the gliding isolates required CO2 and formed acetate and succinate, but not H2S, indole or acetylmethylcarbinol. All fermented glucose, sucrose, maltose and mannose. The organisms may be differentiated on the basis of fermentation of additional carbohydrates, hydrolysis of polymers and reduction of nitrate. Three species are proposed: Capnocytophaga ochracea, Capnocytophaga sputigena and Capnocytophaga gingivalis. Ten isolates did not fit into the proposed species.

Aus Traubenmosten konnten während eines Zeitraumes von etwa 14 Tagen einige Wochen nach Beendigung der Gärung Bakterien isoliert werden, die den enzymatischen Abbau der Äpfelsäure zu Milchsäure und Kohlensäure durchzuführen vermögen. Es Handelt sich bei diesen Bakterien um stäbchenförmige, homofermentative und kokkenförmige, heterofermentative Milchsäurebakterien, die wahrscheinlich den bekannten Arten Lactobacillus plantarum und Leuconostoc citrovorum nahe stehen, aber nicht mit ihnen identisch sind. Vier verschiedene, aus Most isolierte Bakterienstämme werden beschrieben aber nicht neu benannt, um einer evtl. späteren, umfassenden Bearbeitung der im Wein vorkommenden Bakterien nicht vorzugreifen. An Rebenblättern kommen Bakterien vor, die unter anaeroben Bedingungen äpfelsäure abzubauen vermögen, so daß angenommen werden kann, daß die Bakterien ebenso wie die Hefen als Aufwuchsflora der Weintrauben in den Most gelangen.