Zentralblatt für Bakteriologie Mikrobiologie und Hygiene: I. Abt. Originale C: Allgemeine, angewandte und ?kologische Mikrobiologie最新文献

Nitrogen-fixing strains of the Enterobacteriaceae are the most numerous nitrogen-fixing bacteria in the waters and sediments of the Lune estuary. However, their contribution to the nitrogen status of the sediments has been questioned as they have been shown to be intolerant of sea-water salinities. Results presented here show that salinity-tolerant strains of Klebsiella pneumoniae are common and are capable of fixing nitrogen (acetylene reduction) in the sediments.

Mixed cultures of anaerobic cellulolytic bacteria, sulfate reducers (Desulfovibrio vulgaris) and phototrophic bacteria (Chromatium vinosum) were studied. The part played by each microorganism in the food chain and its influence on the behaviour of the other two in this association were elucidated. The major products of cellulose fermentation were formic, acetic and lactic acids, ethanol, hydrogen and carbon dioxide. The hydrolysis of cellulose was slow; 1.37 mg equivalent of glucose per ml medium per hour was released. Desulfovibrio oxidized the organic acids, alcohol and hydrogen by dissimilatory sulfate reduction and sulfide and acetate were accumulated in the medium. The rate of sulfate reduction depends on the rate of cellulose fermentation.

In the presence of phototrophic bacteria, the end products of cellulose degradation and sulfate reduction disappeared from the medium and the protein content increased highly. The growth yield constant increased five times when the cellulolytic organism was associated with the two sulfur bacteria. The absence of Desulfovibrio perturbed the functioning of the trophic chain, as the rate of sulfate reduction partly determines the growth of Chromatium. Chromatium seems to hinder the anaerobic degradation of cellulose, whereas Desulfovibrio seems to enhance it. The microorganisms behave differently in pure and mixed cultures.

Bacteroides multiacidus (Mitsuoka, Terada, Watanabe and Uchida) differs to such an extent from the type species of Bacteroides, Bacteroides fragilis (Castellani and Chalmers), that it cannot be retained in this genus. On the basis of morphological, biochemical and chemical criteria it is suggested that Bacteroides multiacidus be reclassified in a new genus, Mitsuokella, as Mitsuokella multiacidus comb. nov.

A marine, mesophilic, coccoid, lobal, monotrichous flagellated methanogen, growing on methanol and methylamines, but not on H₂/CO₂, is described. The cell envelope consists of protein subunits. The organism is lysed by SDS. The G + C-content of its DNA is 45.9 mol%. The new isolate represents a new genus, Methanolobus, and has been named Methanolobus tindarius.

A bacteriological study of prevalences of Vibrio anguillarum like organisms (VLO) in three marine recipients, polluted with effluents from sugar and cellulose factories, showed some characteristic features.

In the winter period very low counts of VLO were recorded. During temperature rise in spring the VLO values rise to a characteristic level persisting from June to September. A decline occurs at this time, except in sites polluted from sugar plants, where there is a delay of appr. one month.

In the relatively stable period the prevalence of VLO in the recipients is appr. 10–100 per ml water and 1.000–10.000 per gram sediment while the corresponding values for the control are 1–10 per ml and 100–1000 per gram, respectively.

Thus fish living in these recipients are exposed to a ten times higher risk from VLO, which is reflected in a higher prevalence of an ulcus disease in cod. The complicated nature of pollution induced diseases makes it impossible directly to correlate VLO and disease prevalence. Prevalence studies of VLO in marine recipients give valuable information on growth conditions (“organic pollution”) for marine vibrios and the risk to fish, wild living and cultured. Therefore this group of bacteria should to be added to the list of marine indicator organisms, where the indication is based on the environmental risk.

An extensive survey of marine products revealed that only products containing shrimp contained P. citreus P. citreus isolates accounted for 13–24% of the microbial flora of Penaeus shrimp during extended ice storage. After 10 days of shrimp ice storage, Plano-coccus and Pseudomonas were the predominant microorganisms present in Penaeus shrimp. All isolates recovered exhibited good growth over a range of pH 7–10, 5–35 °C and 5–120 g NaCl/1. Proteolysis studies revealed that P. citreus isolates were able to hydrolyze gelatin, cottonseed, soy and more important to the fisheries microbiologists, shrimp protein. P. citreus grew well at ice and refrigerated temperatures (5 °C) and all isolates tested produced an active extracellular enzyme system capable of degrading shrimp protein at this temperature. P. citreus counts increased in the inoculated shrimp stored at 5 °C from 3.0 x 103 bacteria/gram to 1.5 × 108 bacteria /gram at the 16th day. The potential of P. citreus as a “spoiler” of raw shrimp was shown by the rapid increase in total volatile nitrogen/amino acid nitrogen (TVN/AA-N) ratio, pH and trimethyl-amine nitrogen (TMN) content as well as the reduction in percent total extractable protein (TEP) of the inoculated samples. The extracellular proteolytic enzyme of P. citreus was active at refrigeration or iced temperatures; however, maximum activity was exhibited at 35 °C and pH 8. The importance of the extracellular protease enzyme for shrimp quality is discussed.

Lactobacillus kandleri sp. nov., a new heterofermentative species of the subgenus Beta-bacterium, is described. It is known from a single strain isolated from a spring in the Namib Desert, South West Africa. Morphologically, it shows some resemblance with Lactobacillus confusus, but it differs in its ability to ferment a relatively small range of sugars, including mannitol and in that it has a lower (39.1%) GC content. It contains peptidoglycan of the Lys-Ala-Gly-Ala-Ala type, reported for the first time for a Lactobacillus species.

The citrate utilizing ability (Cit⁺) in Klebsiella pneumoniae C3 was simultaneously lost with the abilities to excrete glutamic acid and to biosynthesize proline. Both properties were proved to be plasmid determined (J. Jofre et al., J. Bact. 138, 721–725). Citrate utilization was transferred by conjugation from K. pneumoniae C3 to Escherichia coli K12. Moreover, the transfer of the ability to biosynthesize proline from strain C3 to well-characterized Pro- strains of E. coli established that loci proA and proB, but not proC, are complemented by the plasmid herein described. E. coli exconjugants transferred simultaneously the abilities to utilize citrate and to biosynthesize proline by conjugation to other E. coli strains. Plasmid DNA was detected in E. coli exconjugants either by cesium chloride-ethidium bromide ultracentrifugation or by agarose gel electrophoresis. Gel profiles established that a single plasmid of an estimated molecular weight of 57 megadaltons is present in all examined E. coli exconjugants. Pro₋E. coli were transformed to Pro⁺ Cit⁺ with plasmid DNA of exconjugants. Also, a Cit^-, Pro⁻ and non-glutamic acid excreting strain derived from C3 was rendered Cit⁺, Pro⁺ and glutamic acid excretor by transformation with plasmid DNA from E. coli exconjugants. Therefore it can be concluded that the three phenotypic characteristics above mentioned are complemented by a single conjugative plasmid.

The production of siderophores in 42 isolates of smut fungi parasitizing members of the Caryophyllaceae has been investigated. The parasites originated from 12 species of host plants which are classified in 6 genera of this family. Rhodotorulic acid was isolated from the low-iron culture supernatants of 23 isolates of Ustilago major, U. violacea, and U. violacea var. stellariae. Only U. violaceo-irregularis from Silene vulgaris and U. violacea from Saponaria pumilio and Saponaria officinalis (6 of 7 isolates) failed to produce hydroxamic acids. The results of siderophore formation by the anther smuts of Caryophyllacea are discussed in connection with the current knowledge of the occurrence of hydroxamic acids in Heterobasidiomycetes.