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PubMed2006

The current and future applications of microorganism in the bioremediation of cyanide contamination.

Inorganic cyanide and nitrile compounds are distributed widely in the environment, chiefly as a result of anthropogenic activity but also through cyanide synthesis by a range of organisms including higher plants, fungi and bacteria. The major source of cyanide in soil and water is through the discharge of effluents containing a variety of inorganic cyanide and nitriles. Here the fate of cyanide compounds in soil and water is reviewed, identifying those factors that affect their persistence and which determine whether they are amenable to biological degradation. The exploitation of cyanides by a variety of taxa, as a mechanism to avoid predation or to inhibit competitors has led to the evolution in many organisms of enzymes that catalyse degradation of a range of cyanide compounds. Microorganisms expressing pathways involved in cyanide degradation are briefly reviewed and the current applications of bacteria and fungi in the biodegradation of cyanide contamination in the field are discussed. Finally, recent advances that offer an insight into the potential of microbial systems for the bioremediation of cyanide compounds under a range of environmental conditions are identified, and the future potential of these technologies for the treatment of cyanide pollution is discussed.

Bacteria↗

PubMed2006

Yeasts in high Arctic glaciers: the discovery of a new habitat for eukaryotic microorganisms.

Recently a new habitat for microbial life has been discovered at the base of polythermal glaciers. In ice from these subglacial environments so far only non-photosynthetic bacterial communities were discovered, but no eukaryotic microorganisms. We found high numbers of yeast cells, amounting to a maximum of 4,000 CFU ml(-1) of melt ice, in four different high Arctic glaciers. Twenty-two distinct species were isolated, including two new yeast species. Basidiomycetes predominated, among which Cryptococcus liquefaciens was the dominant species (ca. 90% of total). Other frequently occurring species were Cryptococcus albidus, Cryptococcus magnus, Cryptococcus saitoi and Rhodotorula mucilaginosa. The dominant yeast species were psychrotolerant, halotolerant, freeze-thaw resistant, unable to form mycelium, relatively small-sized and able to utilize a wide range of carbon and nitrogen sources. This is the first report on the presence of yeast populations in subglacial ice.

Arctic Regions↗

PubMed2005

Lactosucrose production by various microorganisms harboring levansucrase activity.

Production of the artificial sweetener, lactosucrose, by various microorganisms containing levansucrase activity was investigated. Of the tested bacteria, Bacillus subtilis was the most effective producer using lactose as an acceptor and sucrose as a fructosyl donor. Lactosucrose production by this strain was optimal at pH 6.0 and 55 degrees C whereupon 181 g lactosucrose l(-1) was produced from 225 g lactose l(-1) and 225 g sucrose l(-1) in 10 h.

Bacillus subtilis↗

PubMed2005

Transformation of ginsenosides Rb1 and Re from Panax ginseng by food microorganisms.

Ginsenosides Rb1 and Re, respectively belonging to the major protopanaxadiol and protopanaxatriol ginsenosides, were transformed using cell-free extracts from food microorganisms. Rb1 was transformed into compound K via Rd and F2 by Bifidobacterium sp. Int57, Bif. sp. SJ32, Aspergillus niger and A. usamii. Lactobacillus delbrueckii, and Leuconostoc paramesenteroides transformed Rb1 into Rh2 via Rd and F2. Bifidobacterium sp. SH5 transformed Rb1 into F2 via Rd. Re was transformed into Rh1 via Rg2 by Bif. sp. Int57 and Bif. sp. SJ32. A. niger transformed Re into Rh1 via Rg1. A. usamii transformed Re into Rg2. Transformation of Rb1 proceeded at a higher rate and needed less amount of enzymes than that of Re. Taken together, these processes would allow a specific bioconversion process possible to obtain specific ginsenosides using an appropriate combination of ginsenoside substrates and specific microbial enzymes.

Aspergillus↗

PubMed2005

Cultivation of microorganisms in the cultural medium made from squid internal organs and accumulation of polyunsaturated fatty acids in the cells.

The disposal and more efficient utilization of marine wastes is becoming increasingly serious. A culture media for microorganisms has been prepared from squid internal organs that are rich in polyunsaturated fatty acids (PUFAs). Both freshwater and marine bacteria grew well in this medium and some bacteria accumulated PUFAs in their lipids, suggesting uptake of exogenous PUFAs. Higher PUFA accumulations were observed in Escherichia coli mutant cells defective either in unsaturated fatty acid biosynthesis or fatty acid degradation, or both, compared to those without these mutations. Therefore, PUFA accumulation in cells can be improved by genetic modification of fatty acid metabolism in the bacteria. Squid internal organs would be a good source of medium, not only for marine bacteria but also for freshwater bacteria, and that this process may be advantageous to make efficient use of the fishery wastes and to produce PUFA-containing microbial cells and lipids.

Animals↗

PubMed2005

Biodegradation of hexachlorocyclohexane (HCH) by microorganisms.

The organochlorine pesticide Lindane is the gamma-isomer of hexachlorocyclohexane (HCH). Technical grade Lindane contains a mixture of HCH isomers which include not only gamma-HCH, but also large amounts of predominantly alpha-, beta- and delta-HCH. The physical properties and persistence of each isomer differ because of the different chlorine atom orientations on each molecule (axial or equatorial). However, all four isomers are considered toxic and recalcitrant worldwide pollutants. Biodegradation of HCH has been studied in soil, slurry and culture media but very little information exists on in situ bioremediation of the different isomers including Lindane itself, at full scale. Several soil microorganisms capable of degrading, and utilizing HCH as a carbon source, have been reported. In selected bacterial strains, the genes encoding the enzymes involved in the initial degradation of Lindane have been cloned, sequenced, expressed and the gene products characterized. HCH is biodegradable under both oxic and anoxic conditions, although mineralization is generally observed only in oxic systems. As is found for most organic compounds, HCH degradation in soil occurs at moderate temperatures and at near neutral pH. HCH biodegradation in soil has been reported at both low and high (saturated) moisture contents. Soil texture and organic matter appear to influence degradation presumably by sorption mechanisms and impact on moisture retention, bacterial growth and pH. Most studies report on the biodegradation of relatively low (< 500 mg/kg) concentrations of HCH in soil. Information on the effects of inorganic nutrients, organic carbon sources or other soil amendments is scattered and inconclusive. More in-depth assessments of amendment effects and evaluation of bioremediation protocols, on a large scale, using soil with high HCH concentrations, are needed.

Aerobiosis↗

PubMed2006

Simultaneous biodegradation of methyl parathion and carbofuran by a genetically engineered microorganism constructed by mini-Tn5 transposon.

A genetically engineered microorganism (GEM) capable of simultaneous degrading methyl parathion (MP) and carbofuran was successfully constructed by random insertion of a methyl parathion hydrolase gene (mpd) into the chromosome of a carbofuran degrading Sphingomonas sp. CDS-1 with the mini-transposon system. The GEM constructed was relatively stable and cell viability and original degrading characteristic was not affected compared with the original recipient CDS-1. The effects of temperature, initial pH value, inoculum size and alternative carbon source on the biodegradation of MP and carbofuran were investigated. GEM cells could degrade MP and carbofuran efficiently in a relatively broad range of temperatures from 20 to 30 degrees C, initial pH values from 6.0 to 9.0, and with all initial inoculation cell densities (10(5)-10(7) CFU ml(-1)), even if alternative glucose existed. The optimal temperature and initial pH value for GEM cells to simultaneously degrade MP and carbofuran was at 30 degrees C and at pH 7.0. The removal of MP and carbofuran by GEM cells in sterile and non-sterile soil were also studied. In both soil samples, 50 mg kg(-1) MP and 25 mg kg(-1) carbofuran could be degraded to an undetectable level within 25 days even if there were indigenous microbial competition and carbon sources effect. In sterile soil, the biodegradation rates of MP and carbofuran were faster, and the decline of the inoculated GEM cells was slower compared with that in non-sterile soil. The GEM constructed in this study was potential useful for pesticides bioremediation in natural environment.

Biodegradation, Environmental↗

PubMed2005

Pharmacoeconomic evaluation of linezolid versus teicoplanin in bacteremia by Gram-positive microorganisms.

OBJECTIVE: The objective of this study was to compare the efficiency of linezolid versus teicoplanin in the treatment of bacteremia produced by Gram-positive microorganisms through a pharmacoeconomic analysis based on clinical results obtained from a previous clinical trial. METHODS: We applied an analysis of cost-effectiveness elaborated through a pharmacoeconomic model. We defined each unit of effectiveness as 'each successfully cured of infections with bacteremia.' We used the program Pharma-Decision (version Hospital 1.1) that allows to build interactive pharmacoeconomic models. Effectiveness data of both antibiotics were obtained from a published clinical trial, while resources consumed were obtained from the same source and from a consensus provided by a local expert panel. Only direct costs were included in the analysis without taking into consideration indirect costs. The perspective chosen was hospital assistance and the time horizon was set to 28 days. All costs are expressed in Euros. RESULTS: Linezolid demonstrated a better clinical outcome with less associated costs compared to teicoplanin (88.5 versus 56.7% of cured patients and 5,557.04 versus 6,327.43 per treated patient, respectively), thus resulting in a lower cost-effectiveness ratio for linezolid versus teicoplanin (6,279.1 versus 11,159.5 per cured patient with a 95% CI of 5,960.2-6,510.4 and 10,865.2-12,647.3, respectively) which results in a the dominant position for linezolid. The sensitivity analysis showed that linezolid was always the most efficient option even when modifying the value of variables with higher uncertainty. CONCLUSIONS: Linezolid is a more efficient option than teicoplanin because it presents higher rate of effectiveness with lower consumption of resources, thus being a dominant alternative in the treatment of Gram-positive infection with bacteremia.

Acetamides↗

PubMed1985

Difference spectroscopy with respiratory membranes of an H2-oxidizing microorganism layered between two gas-permeable, plastic foils: a procedure that allows measurements in the ultraviolet range.

A method for recording redox difference spectra of respiratory membranes which minimizes light scattering and results in increased sensitivity and spectral range when compared to the traditional technique of recording spectra of respiratory particles in suspension is described. Membranes were sandwiched between two gas-permeable, plastic foils, placed in a sealed cuvette, and gassed with H2 as reductant or O2 as oxidant. The membranes of the H2-oxidizing microorganism (Alcaligenes eutrophus H16) used in this work contain a hydrogenase which is coupled to the electron transport chain, thereby allowing H2 to serve as a source of electrons. With this procedure, spectra of both cytochromes and quinones were recorded. By using mixtures of H2 and O2, spectra of cytochromes between the fully oxidized and fully reduced states were recorded.

Alcaligenes↗

PubMed1989

Rapid identification of microorganisms by nucleic acid hybridization after labeling the test sample.

A novel method for rapidly identifying microorganisms has been developed. This method employs a monoadduct-forming furocoumarin derivative, which can photochemically label nucleic acids. The labeled nucleic acid can, in turn, be hybridized simultaneously to a panel of immobilized probe DNAs arrayed as dots on a solid support such as nitrocellulose. This procedure offers several advantages over more conventional hybridization techniques in that sample nucleic acids can be photolabeled without substantial sample preparation and that identification can be achieved by a single, rapid hybridization reaction.

Bacterial Typing Techniques↗

PubMed1989

Quantitative determination of various hopanoids in microorganisms.

A rapid and sensitive method for determination of various hopanoids in microorganisms is described. Tetrahydroxybacteriohopane (THBH), THBH-ether and -glycoside were acetylated with acetanhydride/pyridine and were separated on a C18 reversed-phase HPLC column with a gradient of acetonitrile in methanol and subsequent monitoring of the eluant at 206 nm. Quantification is based on peak area calculation by using purified bacteriohopanoids as external standards. A linear response is found from 10 to 20 micrograms bacteriohopanetetrol and for up to 200 micrograms ether and glycoside of THBH. Diplopterol and diploptene were determined by GLC after silylation with BSTFA/TMSCl in pyridine; the detector response is linear from 0.1 to 2 micrograms.

Bacteria↗

PubMed1991

2-Nitro-5-(6-bromohexanoylamino)benzoic acid test paper method for detecting microorganisms capable of producing cephalosporin acylases.

A novel method for detecting microorganisms capable of producing cephalosporin C (CPC) acylase and/or 7-(4-carboxybutanamido)cephalosporanic acid (GL-7-ACA) acylase has been developed. The method is based on the degradation of 2-nitro-5-(6-bromohexanoylamino)benzoic acid (NBHAB), a chromogenic substrate, into yellow 2-nitro-5-aminobenzoic acid by the action of the CPC acylase or the GL-7-ACA acylase. This method is very sensitive and quite specific, and has been successfully applied to screen the acylases from a variety of bacteria. A large number of colonies isolated on a plate surface from more than 67 samples and several known bacteria were tested by the NBHAB paper. Five NBHAB-positive strains and isolates were obtained. They were further examined by the reaction of their bacterial cells upon CPC and GL-7-ACA, respectively, and by thin-layer chromatography in order to distinguish the CPC acylase from the GL-7-ACA acylase.

Agar↗

PubMed1982

Influence of dietary disaccharides on mouth microorganisms and experimental dental caries in rats.

Osborne-Mendel rats were inoculated with Streptococcus mutans at weaning, divided into 5 groups and fed cariogenic diets containing 56 per cent sugar either as sucrose, maltose, lactose or combinations of sucrose/maltose and sucrose/lactose. The number of Strep. mutans on molar teeth of rats fed the diet high in maltose was much lower than for any other group of rats (p less than 0.01). Although Strep. mutans levels were low for rats fed maltose, the incidence of carious lesions was similar to rats fed sucrose when the textures of the two sugars were similar. Although maltose does not support plaque formation, it is a fermentable carbohydrate which can provide, if microorganisms are present, an environment conducive to dental decay. The incidence of carious lesions was highest among rats fed lactose.

Animals↗

PubMed1990

DNA probes in the diagnosis of periodontal microorganisms.

The need for a rapid and sensitive microbiological assay has become necessary for both research and clinical diagnostic purposes. This need has become clear as a result of extensive documentation linking specific bacterial species and periodontal destruction. DNA probe technology provides both a sensitive and specific assay and alleviates the concern for transport of fastidious microorganisms. The DNA probe procedure includes (1) disruption of bacterial cells with denaturation of DNA, (2) immobilization of DNA onto a nitrocellulose filter, (3) blocking unbound nitrocellulose with non-specific DNA, (4) hybridization of the filter with 32P-labelled probe, (5) washing and detection of bound probe. At our laboratory, microbiological analysis with whole-genomic and cloned DNA probes has been used on thousands of plaque specimens in several large-scale research projects. In one study, levels (greater than or equal to 10(5)) of Actinobacillus actinomycetemcomitans were significantly higher in subjects under 21 yr than in subjects with adult periodontitis (over 21 yr old). In another study, the distribution of periodontal pathogens throughout the mouth was examined. High levels were selectively found at sites with probing depths of 5 mm or more and bleeding on probing, directing specimen collection to these sites. In contrast, random selection of sites for sampling was found to be a poor method for detecting high levels of pathogens. These data suggest appropriate sites for specimen collection for further research and diagnostic purposes.

Actinobacillus↗

PubMed1996

Contribution to the biophysics of the lethal effects of electric field on microorganisms.

The proposed model assumes that the criteria leading to the lethal breakdown of microorganisms suspended in a continuous medium depend on two parameters: (a) the applied electric field must exceed the critical field of membrane to create holes and (b) the Joule energy (deposited in the membrane) must exceed the minimum value beyond which the cell can not recover. The first parameter initiates (reversible) breakdown and the second one, the completion of the (irreversible) electrical breakdown leading to death of the cell. The number of cells surviving the electric field treatment is related to statistical distribution of cell size. Comparison between theory and the experimental results of Kinosita and Tsong (1977); Hülsheger et al. (1980, 1981, 1983); Rosemberg and Korenstein (1990) and others is given.

Bacterial Physiological Phenomena↗

PubMed1996

Relevance, pathogenicity and virulence of microorganisms in implant related infections.

It is impossible to imagine modern medicine today without indwelling devices of various kinds. The time that these implants or prostheses remain in the patient's body can vary from a few hours, e.g. intravenous catheter, to his entire life, e.g. hip prosthesis, heart valve. Besides the indisputable use and advantages of this type of medical intervention for the patient, e.g. saving his life or improving its quality, the associated complications should not be overlooked. One of the most frequent and significant complications of implant surgery is the manifestation of infection in the tissue around the implant. That infection occurs is not surprising since the indwelling devices predispose to bacterial and mycotic infection on the one hand and impede its eradication on the other. The consequences of infection for the patient may mean the loss of regained mobility and independence, hospitalization for sepsis, or even death. Microbes per se are not necessarily pathogenic, however, there are numerous virulence factors which affect the degree of pathogenicity of the microorganisms. These include, for example, various enzymes, (e.g. catalase, hyaluronidase, collagenase and other proteases), and specific surface structures, e.g. the polysaccharide capsules of pneumococci or the lipopolysaccharides of Gram negative bacteria, and the production of bacterial toxins, e.g. leucozidin, streptolysine. The strategies which the pathogenic bacteria employ in their efforts to occupy the host include adherence, penetration and multiplication, antiphagocytosis and serum resistance, the formation of siderophores, antiimmunity, and cell and tissue damage. An attempt will be made here to present an overview of this multifactorial event in which the host obviously plays an important role.

Animals↗

PubMed1990

A tube latex test based on colour separation for the detection of IgM antibodies to either one of two different microorganisms.

A simple two stage assay was developed for the detection of IgM antibodies to either one of two microorganisms chosen arbitrarily for this study. Salmonella enteritidis and Trichinella spiralis. In the first stage, magnetic polystyrene beads (Dynabeads) coated with anti-mu (mouse) antibodies were incubated with the test material for 45 min to capture the IgM antibodies. In the second stage, indicator latex particles were incubated with the Dynabeads for 30 min and the results read following settlement of the Dynabeads under the influence of a magnet. Two types of indicator particles were used: blue-coloured (sensitized with Trichinella antigen) and red-coloured (sensitized with Salmonella antigen). These were mixed in suitable proportions to form a purple suspension. Reaction of either type of latex particles due to binding to the adsorbed IgM antibodies resulted in the settlement of that particle and hence a change of colour in the suspension to either red (if Trichinella-specific antibodies alone were present) or blue (if Salmonella-specific antibodies alone were present). When applied to the sera (used at 1/10 dilution) of both normal and immunized mice, the assay was positive for all but one (18) immune sera, and negative for all but one (9) normal sera.

Animals↗

PubMed1992

An opioid growth factor regulates the replication of microorganisms.

An opioid growth factor (OGF), [Met5]-enkephalin, interacts with the zeta (zeta) opioid receptor to modulate development of eukaryotes. We have found that [Met5]-enkephalin, an endogenous opioid peptide serves to inhibit the growth of S. aureus. This effect on growth involves cell proliferative events and is under tonic control, since potent opioid antagonists accelerate cell replication. Both the OGF and zeta opioid receptor were associated with these microorganisms. Other opioid receptors (mu, delta and kappa) were not detected. OGF also controlled the growth of other bacteria: P. aeruginosa and S. marcesans. These results indicate that OGF and its receptor, known to be important in the regulation of mammalian development, also function in the growth of simple unicellular organisms. We suggest that the endogenous opioid system related to growth originated billions of years ago.

Enkephalin, Methionine↗