Studies on Vitamin B6 Metabolism in Microorganisms

A new phosphotransferring reaction which phosphorylated pyridoxine through the phosphoryl group transfer from p-nitrophenylphosphate was found, and the distribution of the reaction in several microorganisms was investigated. The transferring activity was widely distributed in various kinds of microorganisms, especially in fungi belonging to genus such as Aspergillus. The phosphorylated product was isolated from the reaction mixture with the dried cells of Aspergillus flavus and identified as pyridoxine 5′-phosphate.     

Effect of water velocity on the early development of manganese-depositing biofilm in a drinking-water distribution system

Abstract A study of the development of biofilm colonizing the surfaces of pipes in a drinking-water distribution system has shown that water velocity significantly influenced the nature and physiological activity of the biofilm. Biofilm developed at a velocity of 0.5 m s⁻¹ actively oxidized and deposited manganese, but at 0.01 m s⁻¹ no manganese was deposited. Budding bacteria were the dominant microorganisms depositing manganese but a variety of other organisms were also present in the biofilms. The budding bacteria oxidizing manganese were Pedomicrobium manganicum and Metallogenium .     

Results of the storage of freeze dried microbial cultures for 25 years

Saprophytic microorganisms belonging to different physiological groups (Azotobacter, acetic, ammonifying, lactic and nodule bacteria, a phototrophous purple bacterium of the Chromatium genus, bacteria of the Micrococcus and Pseudomonas genera, and a yeast of the Candida genus) were stored at 3-6 degrees C for 25 years in the freeze-dried state. All of the strains were found to be viable after the storage. The number of viable cells decreased for some bacteria, but to a far less degree than when the cultures were kept immediately after the freeze-drying for a year at 30 degrees C.     

Subordination of the taxa of gram-negative bacteria determined by numerical analysis methods

Various numerical methods were used to estimate the coordination of taxa of gram-negative aerobic and facultative anaerobic organoheterotrophic and chemolithotrophic bacteria. Stable phena were found to be formed by cultures belonging to the families Rhizobiaceae, Halobacteriaceae, Enterobacteriaceae, Nitrobacteriaceae (except the genus Nitrobacter), and Methylomonadaceae (except the genus Methylococcus). The unstable position was found in the genera Thermus, Zoogloea, Xanthomonas, Sulfolobus, Methylococcus, Alcaligenes, Brucella, and Acetobacter. The greatest scatter among the objects being analysed was detected among genera belonging to the family Pseudomonadaceae. The taxonomic position of these genera must be defined more precisely. The family Methylomonadaceae is related to such physiologically unique groups of microorganisms as nitrifying, sulfate-reducing, extreme thermophilic and halophilic forms. All in all, the data reported in this work show that numerical analysis can be used to specify the classification structure of bacteria. In a number of cases, the results are consistent with those changes which are performed in the Bergey Manual 9 using logical analysis (for instance, concerning the position of the genera Gluconobacter, Acetobacter, Beijerinckia, and Derxia).     

Nucleotide composition and homologies in the DNA of new extreme halophilic soil archaebacteria

DNA nucleotide composition was studied in extreme halophilic bacteria belonging to the genera Halobacterium, Halococcus, Natronobacterium and Natronococcus. The cultures were shown to be a monolithic group of microorganisms with the content of GC pairs typical of extreme halophilic archebacteria. The difference between the content of DNA major and minor components was twice as high in Halobacterium distributus strains isolated from sulfate saline soils as compared to cultures of this species isolated from natural waters with a high salinity. DNA minor components were not found in haloalkalophilic microorganisms from soda saline soils in contrast to those from soda lakes. The results of DNA-DNA hybridization indicate that the Halobacterium genus is highly heterogeneous. The newly isolated strains of extremely halophilic H. distributus are characterized by the low homology of their DNAs both among themselves and with other species of the genus. However, the hybridization data for the collection strains H. vallismortis 1398 and H. halobium 996 from the National Collection of Microorganisms are indicative of a high homology (80-100%) which is not characteristic of cultures belonging to different species. These results as well as some phenotypical properties of H. vallismortis 1398 different from those of this species type strain support the data reported in the literature about the genetic instability of extreme halophilic archebacteria. The analysis of homologies in DNA nucleotide sequences may be used to study the taxonomy of extreme halophilic archebacteria.     

Evaluation of quantitative and qualitative composition of cultivated acidophilic microorganisms by real-time PCR and clone library analysis

Quantitative and qualitative composition of the cultivated acidophilic microorganisms obtained from the enrichment cultures on the universal medium inoculated with the samples of Shanuch deposit (Kamchatka peninsula) was investigated. The clone library (N = 93) containing eubacterial and archaeal 16S rRNA gene insertions was analyzed. DNA sequences were grouped into 5 ribotypes related to four known genera and one family. Most microorganisms (92%) were shown to belong to the genus Acidithiobacillus. One more group of microorganisms was identified as belonging to the family Acetobacteriaceae (3%); one microorganism was identified as a member of the genus Acidiphilium. Apart from eubacteria, the sequences specific for archaea of the genera Thermococcus (3%) and Ferroplasma (2%) were found; however, these sequences could not be reliably referred to any known species. Quantitative ratio of the microorganisms from the enrichment cultures was determined using real-time PCR. Species-specific test systems were used to determine that the sequences of A. ferrooxidans, A. thiooxidans, and Ferroplasma acidiphilum present in the samples in the ratio of 62, 4, and 0.14%, respectively.     

Determination of the ecological niche of Bacteroides in the gastrointestinal tract--a study of a model of sterile intestines in germ-free animals

The interrelations of the population of microorganisms belonging to the genus Bacteroides with the structures of the mucous membrane of the gastrointestinal tract of germ-free guinea pigs and mini-pigs have been studied. A considerable part of the population of these anaerobic microorganisms is associated in some way with the intestinal mucosa; at least, quite a number of these organisms inhabit mucins covering the mucosa. The determination of this ecological niche occupied by bacteroids in the intestinal microbiocenosis suggests that these organisms have considerable influence on the physiological functions and pathological states of the digestive tract.     

Draft genome sequence of Leucobacter chromiiresistens, an extremely chromium-tolerant strain

Here we present the draft genome of Leucobacter chromiiresistens. This is the first genome sequence of an organism belonging to the genus Leucobacter. L. chromiiresistens was sequenced due to its capability to tolerate up to 300 mM Cr(VI) in the medium, which is so far a unique feature for microorganisms.     

Clusterization of halophilic and halotolerant eubacteria using whole-cell protein electrophoresis data

Total cell proteins of the nineteen halophilic and halotolerant eubacteria isolated from marine sediments and highly mineralized formation waters of oil fields were investigated by SDS gel electrophoresis. The microorganisms studied, phenotypically identified as belonging to the genera Dietzia, Rhodococcus, Staphylococcus, Cytophaga, Brevibacterium, and Archangium, were found to form clearly distinguishable clusters (20-30% similarity at the generic level) on the dendrogram derived from electrophoretic protein patterns. Protein similarity data confirmed the heterogeneity of Rhodococcus maris and its relatedness to the genus Dietza.     

Isolation of antibiotic-producing Actinomycetes from soil samples exposed to UV light

The use of nonroutine means in isolation of microorganisms from natural substrates extended the possibilities of detecting new cultures which often appear to be producers of previously unknown antibiotics. A new procedure for isolating actinomyces of definite groups was developed. It implies preliminary exposure of soil suspensions to UV light. With the use of the procedure, 2539 strains of actinomycetes belonging to different genera were isolated. There was a marked decrease after the irradiation in isolation of cultures belonging to Streptomyces, a genus most widely distributed in nature and studied in detail while isolation of cultures belonging to other genera, promising as sources of novel antibiotics, increased. Micromonospora, Amycolatopsis and Nocardia proved to be the most stable to the effect of UV light. With the use of the procedure it is possible to increase 2-3-fold isolation of cultures belonging to Micromonospora, a genus known as a producer of many antibiotics including those used clinically.     

Autostabilization of the pH in a batch culture of Pseudomonas

Ranges within which the pH of the environment can be self-regulated have been determined for microorganisms belonging to the Pseudomonas genus. The ability of these microorganisms to self-regulate the pH was detected both at an increase and a decrease in the pH of the environment as compared to its optimal value. The rate of self-regulation appears to be proportional to the concentration of viable cells in a suspension. The results may be used for creating an economical system for maintaining the pH of the environment in industrial fermentation.     

The search for strains producing new restriction endonucleases

The search for restrictases in 154 strains belonging to 104 species of 32 genera of microorganisms has been carried out by the method of rapid toluene assay. In 10 strains the activity of endonucleases specifically fragmenting the DNA of phage lambda in the presence of Mg2+ ions has been detected. Restrictases Pae I and Pae II formed by two Pseudomonas aeruginosa strains have been identified as the true isoschizomers of restriction endonucleases Sph I and Sma I respectively. The results of the screening of restrictase-producing strains indicate that the production of restrictases is widely spread among microorganisms of the genus Bacillus.     

Antimicrobial peptide diversity in the skin of the torrent frog, Amolops jingdongensis

Antimicrobial peptide diversity has been found in some amphibians. The diversity of antimicrobial peptides may have resulted from the diversity of microorganisms encountered by amphibians. Peptidomics and genomics analyses were used to study antimicrobial peptide diversity in the skin secretions of the torrent frog, Amolops jingdongensis. Thirty-one antimicrobial peptides belonging to nine groups were identified in the skin secretions of this frog. Among them, there are two novel antimicrobial groups (jingdongin-1 and -2) with unique structural motifs. The other seven groups belong to known antimicrobial peptide families, namely brevinin-1, brevinin-2, odorranain-F, esculentin-2, temporin, amolopin-3, and ranacyclin. Combined with previous reports, more than 13 antimicrobial peptide groups have been identified from the genus Amolops. Most of these antimicrobial peptide groups are also found in amphibians belonging to the genus Rana or Odorrana which suggests a possible evolutionary connection among Amolops, Rana, and Odorrana. Two novel antimicrobial groups (jingdongin-1 and -2) were synthesized and their antimicrobial activities were assayed. Some of them showed strong antimicrobial abilities against microorganisms including Gram-negative and -positive bacteria, and fungi. The extreme diversity of antimicrobial peptides in the Amolops amphibians was demonstrated. In addition, several novel peptide templates were provided for antimicrobial agent design.     

Diversity of five anaerobic toluene-degrading microbial communities investigated using stable isotope probing

Time-series DNA-stable isotope probing (SIP) was used to identify the microbes assimilating carbon from [(13)C]toluene under nitrate- or sulfate-amended conditions in a range of inoculum sources, including uncontaminated and contaminated soil and wastewater treatment samples. In all, five different phylotypes were found to be responsible for toluene degradation, and these included previously identified toluene degraders as well as novel toluene-degrading microorganisms. In microcosms constructed from granular sludge and amended with nitrate, the putative toluene degraders were classified in the genus Thauera, whereas in nitrate-amended microcosms constructed from a different source (agricultural soil), microorganisms in the family Comamonadaceae (genus unclassified) were the key putative degraders. In one set of sulfate-amended microcosms (agricultural soil), the putative toluene degraders were identified as belonging to the class Clostridia (genus Desulfosporosinus), while in other sulfate-amended microcosms, the putative degraders were in the class Deltaproteobacteria, within the family Syntrophobacteraceae (digester sludge) or Desulfobulbaceae (contaminated soil) (genus unclassified for both). Partial benzylsuccinate synthase gene (bssA, the functional gene for anaerobic toluene degradation) sequences were obtained for some samples, and quantitative PCR targeting this gene, along with SIP, was further used to confirm anaerobic toluene degradation by the identified species. The study illustrates the diversity of toluene degraders across different environments and highlights the utility of ribosomal and functional gene-based SIP for linking function with identity in microbial communities.     

Lipid modulation by environmental stresses in two models of extremophiles isolated from Antarctica

Thermoacidophilic and halotolerant microorganisms from the Antarctic continent were studied for their lipid modulation under stress growth conditions. Temperature-induced changes in complex lipids and fatty acids of four strains belonging to the genus Alicyclobacillus involved the relative proportions of different polar lipids and the synthesis of ω-cyclohexyl-acyl chains, which were favoured by high temperatures. Studies were carried out on the lipid composition of four strains of extremely halotolerant bacteria belonging to the genus Micrococcus grown at different salt concentrations from 0 up to 4.5 M NaCl. The main lipids found were two unidentified glycolipids and two phospholipids: 1,2 diacylglycero-3-phosphoryl-glycerol (PG) and cardiolipin (DPG). Among the strains analysed, the lipids of the Micrococcus strain Erebus were shown to be strongly influenced by salt concentrations, in that DPG and one glycolipid were absent at a low salt molarity while, under these conditions, PG was the main lipid found. The predominant fatty acids in all halotolerant strains were of the anteiso type; growth under increasing salinity gave rise to an increase in long chain fatty acids and of straight chain fatty acids, while a decrease in iso fatty acids occurred. Accepted: 20 May 2000     

Anisotropic structures of some microorganisms studied by polarization microscopy

Polarization microscopy has been used to study the internal structures of microbial cells and in terms of the birefringence of these structures and its possible relation to the cell function and composition. Cyanobacteria of the genus Phormidium were found to contain no anisotropic structures, while other microorganisms were found to contain them, albeit to a different extent, size, and number. The flagellate Euglena was found to contain two large anisotropic bodies, whereas the flagellate of the genus Phacus belonging to the same systematic group Euglenales was observed to contain only one large anisotropic body (storage substances—paramylon). On the other hand, green algae of the genus Scenedesmus, whose cells form four-celled coenobia, contained clusters of small anisotropic granules composed also of storage substances (volutin). Minute anisotropic granules (storage substances) in two smaller clusters were found also in diatoms of the genus Navicula, whereas the green alga of the genus Mougeotia was revealed to contain, in addition to minute anisotropic granules (storage substances) occurring in low numbers in the cytoplasm, also a strongly birefringent cell wall (shape birefringence). Cells of the amoeba of the genus Naegleria and heliozoans of the genus Heterophrys were observed to contain only isolated tiny anisotropic granules (storage substances).     

Conjugative transfer of a plasmid from Escherichia coli to various strains of the order Actinomycetales

The conjugal transfer of autonomous and integrative plasmids from the donor strain Escherichia coli S17-1 to strains of genera Actinomadura, Arthrobacter, Kitasatoa, Micromonospora, Nocardia, Rhodococcus, Saccharopolyspora, and to 16 strains of the genus Streptomyces was demonstrated. The status of plasmids in recipient strains and the stability of their inheritance were analyzed. Plasmids constructed for strains of the genus Streptomyces were shown to function in a large number of strains belonging to the order Actinomycetales. The well-developed system of Streptomyces vector molecules and cloned genes of antibiotic biosynthesis allows their transfer to those microorganisms for which conventional techniques of plasmid transfer by regenerated protoplast transformation or electroporation have not been developed or are inefficient.     

Dephosphorization of LD slag by phosphorus solubilising bacteria

Phosphorus is one of the major nutrients, and microbial solubilisation of insoluble mineral phosphate in soil is an important process in natural ecosystem and in agricultural soil. Many soil microorganisms display the ability to solubilize many insoluble inorganic phosphates. They are generally referred as phosphorus solubilising microorganisms (PSM). In this study an attempt was made to look into the phosphorus solubilisation efficiency of some commonly available soil bacteria and their possible application in bio-beneficiation of metallurgical waste like LD Slag. Linz -Donawitz (LD) slag is produced in large quantities (200 kg LD slag per ton of hot metal) and poses a substantial disposal problem in the iron and steel making industry. LD slag contains around 29% Ca, 21% Fe, and 5% Mg. Its phosphorus content is about 1.5-6%. Due to presence of high amount of Ca, it can be used as flux in blast furnace, but presence of high amount of phosphorus in the LD slag makes them unsuitable for industrial application. Removal of phosphorus with the help of phosphorus solubilising microorganisms may be a great advantage in biotechnological applications. Two gram positive bacteria belonging to genus Bacillus and two gram negative bacteria belonging to genus Pseudomonas were selected in this study. Phosphorus solubilisation efficiency was studied initially with tricalcium phosphate as model insoluble phosphate compound at different sugar concentration, NaCl concentration and at different initial pH of the medium. About 35% of ‘P’ could be solubilized from LD slag by Pseudomonas aeruginosa at 2% solid content.