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At least 1,171 records · Page 65Linked to original sources
PubMed2005

[The community and structure of nitrogen-fixing microorganism in Sanjiangyuan natural reserve].

Research on the diversity of microorganism community in natural environment has been concerned hot spot using the newly molecular biotechnology in the world now. To understand the composition and structure of nitrogen-fixing bacteria communities in the Qingzang plateau, the molecular diversity and phylogenetic of nifH genes of Sangjiangyuan natural reserve were examined by using the PCR-RFLP based cloning approach. The 3 samples were come from different sites and different plant types, and their biogeochemical parameters were diverse. DNA was directly extracted from the soil microorganism and amplified the nifH gene fragment using PCR by the primers of nifH-34F 5'-AAAGG(C/T)GG(A/T) ATCGG(C/T)AA(A/G) TCCACCAC-3' and nifH-491R 5'-TFGTT(G/C)GC(G/C)GC(A/G)TACAT(G/C)GCCATCAT-3'. For the nifH gene segment, diverse PCR products were characterized by cloning, restriction fragment length polymorphism (RFLP) analysis and sequencing. A total of 233 clones and 99 operational taxonomic units (OTUs) which were digested the clones by the restriction enzymes MspI and RsaI were obtained from all samples. YS-1 had 63 clones and 24 OTUs, ZD-1 had 75 clones and 28 OTUs, and NQ-1 had 95 clones and 47 OTUs, respectively. They were found 1-2 significant domain groups of clones and shared 4 OTUs in all samples. A wide range of sequence divergence was observed in the 26 nifH clones that were sequenced from all samples. Sequence comparison showed that the nifH clones were 66% to 98% similar. The phylogenetic tree was constructed by the Clustal W and Mega software. 26 sequences could be subdivided into 4 clusters in the phylogenetic tree, and some of them had the closely similar to Proteobacteria, but The majority of the clones were not closely related to any known cultivated nitrogen-fixing bacteria, Therefore, most of them are unique and may represent novel sequences of nitrogen-fixing bacteria.

Bacteria↗
PubMed1992

[Density and activity of microorganisms of the carbon cycle under the canopy of Myrica gale L].

Plants, especially actinorhizal, regulate edaphic microflora through various ways, modifying thus nutrients recycling. Myrica gale effect on microorganisms in the carbon cycle is studied in this work by comparing soil samples collected under the canopy in summer and control samples. The results indicate that under M. gale C-organic and N-total concentration and anaerobic cellulolytic, hemicellulolytic and amilolytic density increase, and pH, C/N ratio and aerobic cellulolytic microorganisms density decrease. Microbial activity in soil is also modified.

Bacteria, Aerobic↗
PubMed2005

[The occurrence of microorganisms in intraoral abscesses].

The aim of this study was to assess the occurrence of microorganisms in 39 intraoral abscesses. The samples were place in transport medium. The materials were inoculated on adequate enrichment and selective media and cultivated under anaerobic and aerobic conditions. The microorganisms were found in all samples (100%), Anaerobic bacteria most frequently were recovered. The predominant anaerobes were from genus Prevotella, Bacteroides, Fusobacterium and Peptostreptococcus. Among aerobic bacteria, the most frequent were gram-positive cocci. The microaerophilic bacteria and fungi most rarely were isolated from pus samples.

Abscess↗
PubMed2005

Degradation of crude oil by indigenous microorganisms supplemented with nutrients.

Different kinds of mineral nutrients(NO3-N, NH4-N and PO4-P) were applied in the simulated oil-polluted seawater for enhancing oil biodegradation in the N/P ratio 10:1 and 20:1. Although indigenous microorganisms have the ability to degrade oil, adding nutrients accelerated biodegradation rates significantly. For the group amended with NO3-N and PO4-P in the ratio 10:1, the reaction rate coefficient was 4 times higher than the natural biodegradation. Chemical and microbiological analysis showed that the optimal N/P ratio in the system is 10:1, and microorganisms tend to utilize nitrate rather than ammonium as N source.

Biodegradation, Environmental↗
PubMed2005

[Resistant microorganisms in patients transferred from foreign hospitals].

OBJECTIVE: To determine the prevalence of carriers of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and gentamicin-resistant Gram-negative bacilli (GGNB) in patients repatriated from foreign hospitals to The Netherlands. DESIGN: Determination of prevalence. METHOD: In the period May 1998-August 2001, 1167 patients were repatriated. Swab specimens, demographic data and clinical data were obtained during the transfer. RESULTS: The prevalence of carriers of resistant microorganisms was 18.2%. MRSA was carried by 2.7% of the total repatriated group and by 4.7% of patients transferred to a Dutch hospital. Risk factors were antimicrobial treatment (odds ratio (OR): 3.4; 95% CI: 1.2-9.7), length of stay in a foreign hospital > or = 14 days (OR: 5.4; 95% CI: 2.3-12) and artificial ventilation (OR: 8.5; 95% CI: 1.8-41). VRE and GGNB were isolated from 2.7% and 14.1% of patients, respectively. Transfer from Asia or southern, south-eastern and eastern Europe were risk factors for carrying GGNB. CONCLUSION: Carriership of resistant microorganisms was high among repatriated patients. The highest risk of GGNB was more closely associated with the country from which the patient was transferred than the antimicrobial treatment received in the foreign hospital.

Carrier State↗
PubMedDate not supplied

[Isolated pathogen microorganisms in respiratory samples from children with cystic fibrosis].

Cystic Fibrosis (CF) is characterized by a dysfunction of the exocrine secretion glands. The first symptoms often appear in the respiratory system which constitutes one of the most important morbimortality causes in these patients. Chronic respiratory tract colonization is caused mainly by bacteria such as Staphylococcus aureus, Haemophilus spp. and Pseudomonas aeruginosa. Respiratory samples from patients with CF (age group: 4 months to 11 years) were analyzed from November 2001 to August 2004. The most frequently isolated microorganisms were S. aureus (38.7%), P. aeruginosa (37.4%) and Haemophilus spp (15.3%). A high resistance to erithromycine (35.0%) and clindamicine (29.4%) was observed in S. aureus strains and 25.9% of them were methicillin-resistant. P. aeruginosa strains were mainly gentamicin-resistant (31.0%). The rate of ampicillin-resistant Haemophilus spp. was 23.0% and it was due to the presence of beta-lactamases, but a high trimethoprim-sulfamethoxazole resistance was observed in this microorganism (59.0%).

Bacteria↗
PubMed2006

Apoptotic potential of the concentrated effective microorganism fermentation extract on human cancer cells.

The effective microorganism fermentation extract (EM-X, the first generation) was claimed to possess strong anti-oxidation property. On the other hand, we have shown that the second generation of the effective microorganism fermentation extract (EM-X2) possessed growth inhibition on human cancer cells involving MDA-MB231 breast cancer and K-562 chronic myelogenous leukaemia cells. Elevation of super oxide dismutase activity from EM-X2 treated cancer cell extract was observed. However, the possible anti-cancer activity of the first generation of the EM-X was not reported. Here we demonstrate that the concentrated form of the EM-X from its original fluid also possess antiproliferation ability together with induction of apoptosis on the human cancer cell lines including Hep3B hepatocellular carcinoma (HCC) and KG1a acute myelogenous leukaemia (AML). Similar effect could also be demonstrated on primary cultured bone marrow samples isolated from patients with AML. Morphological inspection revealed that common apoptotic feature was found on these concentrated EM-X treated cancer cells. Both the anchorage-dependent clonogenicity assay on Hep3B HCC and methyl-cellulose colony formation assay on KG1a cells and bone marrow cells from AML patients further revealed the ability of the concentrated EM-X on reducing their colony formation ability. Incubating KG1a with concentrated EM-X readily induced apoptosis as demonstrated by flow cytometric analysis. Interestingly, few growth inhibition effect of the concentrated EM-X was observed on both the SV40 transformed THLE-2 liver epithelial cells and primary cultured non-malignant haematological disordered bone marrow. Collectively, this concentrated EM-X is effective in inducing cell death and reducing the regeneration potential of both Hep3B HCC and KG1a AML cells in vitro.

Antioxidants↗
PubMed2005

Exposure of Indian agricultural workers to airborne microorganisms, dust and endotoxin during handling of various plant products.

Microbiological air sampling with the use of personal sampler was performed in 14 small agricultural facilities located in Aurangabad (Southern India), including 5 farms (at harvesting and threshing), 6 godowns (small food storing and processing settings) and 3 grain or cotton mills. In 12 facilities, including harvesting on farms, godowns and mills, concentrations of airborne microorganisms were relatively low, ranging from 1.5 x 10(3) - 8.2 x 10(4) cfu/m(3). The striking rise in the concentrations of airborne microbes, by 2-4 orders of magnitude, was noted on 2 farms during threshing of maize (4.2 x 10(6) cfu/m(3)) and pearl millet (1.1 x 10(7) cfu/m(3)). This was due to release of large quantities of bacteria. During threshing of maize, the most common microorganisms were thermophilic actinomycetes (40 % of the total count) and mesophilic actinomycetes of the genus Streptomyces (39 %), while during threshing of pearl millet the most abundant were corynebacteria (68 %) and Gram-negative bacteria (22 %). Mesophilic bacteria formed 16.7-100 % of the total airborne microflora and were prevalent in 11 out of 14 facilities. Thermophilic actinomycetes and fungi formed respectively 0-43.1 % and 0-83.3 % of the total count and were prevalent in 1 and 2 facilities. The concentrations of airborne dust and endotoxin recorded in the examined agricultural facilities, in most cases were very large and ranged from 2.5-257.5 mg/m(3), and from 0.0625-125.0 microg/m(3), respectively. In 10 out of 14 facilities, the concentrations of dust were of the order 10(1)-10(2) mg/m(3), ranging from 25.0-257.5 mg/m(3). Similarly, in 7 out of 14 facilities the concentrations of endotoxin were of the order 10(1)-10(2) microg/m(3), ranging from 31.25-125.0 microg/m(3). In conclusion, Indian agricultural workers could be exposed during handling of various plant materials to airborne biological hazards posing a risk of work-related respiratory disease. Of these, the most important are: bacterial endotoxin and allergenic species of bacteria and fungi. The greatest risk occurs at threshing of pearl millet and maize which requests an application of the appropriate prevention measures, such as wearing respirators by the workers and using modern threshing machines reducing the dustiness.

Agricultural Workers' Diseases↗
PubMedDate not supplied

[Phylogenetic diversity and activity of anaerobic microorganisms of high-temperature horizons of the Dagang Oilfield (China)].

The number of microorganisms of major metabolic groups and the rates of sulfate-reducing and methanogenic processes in the formation waters of the high-temperature horizons of Dagang oilfield have been determined. Using cultural methods, it was shown that the microbial community contained aerobic bacteria oxidizing crude oil, anaerobic fermentative bacteria, sulfate-reducing bacteria, and methanogenic bacteria. Using cultural methods, the possibility of methane production from a mixture of hydrogen and carbon dioxide (H2 + CO2) and from acetate was established, and this result was confirmed by radioassays involving NaH14CO3 and 14CH3COONa. Analysis of 16S rDNA of enrichment cultures of methanogens demonstrated that these microorganisms belong to Methanothermobacter sp. (M. thermoautotrophicus), which consumes hydrogen and carbon dioxide as basic substrates. The genes of acetate-utilizing bacteria were not identified. Phylotypes of the representatives of Thermococcus spp. were found among 16S rDNAs of archaea. 16S rRNA genes of bacterial clones belong to the orders Thermoanaerobacteriales (Thermoanaerobacter, Thermovenabulum, Thermacetogenium, and Coprothermobacter spp.), Thermotogales, Nitrospirales (Thermodesulfovibrio sp.) and Planctomycetales. 16S rDNA of a bacterium capable of oxidizing acetate in the course of syntrophic growth with H2-utilizing methanogens was found at high-temperature petroleum reservoirs for the first time. These results provide further insight into the composition of microbial communities of high-temperature petroleum reservoirs, indicating that syntrophic processes play an important part in acetate degradation accompanied by methane production.

Anaerobiosis↗
PubMed2006

[Distribution of phosphine and microorganisms in partial sediments of Lake Taihu].

Phosphine in Lake Taihu sediment cores were monitored by a GC/NPD method, coupled with cryo-trapping enrichment technology. Results show that phosphine is universally detected in sediment cores, its concentration ranges from 0.15 ng/kg to 36.1 ng/kg. The concentration of phosphine varies with different sampling sites and depths. Representative microorganisms (aerobic bacteria, anaerobic bacteria, actinomycete, inorganic phosphobacteria and organic phosphobacteria) in surface sediments were also identified. The amount and distribution of microorganisms positively correlate with different contamination and salty levels of the samples. A markedly positive linear correlation between the concentration of phosphine and the numbers of inorganic phosphobacteria could be observed (R2 = 0.817, n = 6). There is not a correlation between phosphine level and organic phosphobacteria quantities.

Bacteria↗
PubMed2006

[Molecular evidence for the lysogenic state of microorganisms belonging to the genus Bordetella and characterization of Bordetella parapertussis temperate bacteriophage 66(2.2)].

A new bacteriophage phiK of microorganisms belonging to the genus Bordetella was isolated from cells of the earlier characterized strains 66(2-2) (1 and 2) obtained upon phage conversion of B. parapertussis 17903 cells by B. pertussis bacteriophage phi134. Bacteriophage phiK is identical to previously described Bordetella bacteriophages phiT, phi134, and phi214 in morphology and some biological properties but has a permuted genome different from all other phages. DNA of bacteriophage phiK is not integrated in the chromosome of B. parapertussis 17903, similar to DNA of bacteriophages phiT, phi134, and phi214 that are not integrated into B. pertussis and B. bronchiseptica chromosomes, but may be present in a small part of the bacterial population as linear plasmids. Sequences homologous to DNA of bacteriophage phiK were detected in the chromosome of strain 66(2-2) (1 and 2) and in chromosomes of all tested strains B. pertussis and B. bronchiseptica. Prophage integration in chromosomes of microorganisms of the genus Bordetella may vary in different bacterial strains and species. An assumption about abortive lysogeny of B. parapertussis bacteria for phiK phage and of B. bronchiseptica for closely related phages phiT, phi134, and phi214 has been advanced. The possibility of involvement of B. pertussis insertion sequences in the formation of the chromosomal structure in 66(2-2) convertants and in phage genomes is considered.

Bacteriophages↗
PubMedDate not supplied

Surface plasmon resonance biosensors for detection of pathogenic microorganisms: strategies to secure food and environmental safety.

This review describes the exploitation of exclusively optical surface plasmon resonance (SPR) biosensors for the direct and indirect detection of pathogenic microorganisms in food chains and the environment. Direct detection is, in most cases, facilitated by the use of defined monoclonal or polyclonal antibodies raised against (a part of) the target pathogenic microorganisms. The antibodies were immobilized to a solid phase of the sensor to capture the microbe from the sample. Alternatively, antibodies were used in an inhibition-like assay involving incubation with the target organism prior to analysis of nonbound antibodies. The free immunoglobins were screened on a sensor surface coated with either purified antigens or with Fc or Fab binding antibodies. Discussed examples of these approaches are the determination of Escherichia coli O1 57:H7, Salmonella spp., and Listeria monocytogenes. Another direct detection strategy involved SPR analysis of polymerase chain reaction products of Shiga toxin-2 genes reporting the presence of E. coli O157:H7 in human stool. Metabolic products have been exploited as biomarkers for the presence of a microbial agent, such as enterotoxin B and a virulence factor for the occurrence of Staphylococcus aureus and Streptococcus suis, respectively. Indirect detection, on the other hand, is performed by analysis of a humoral immune response of the infected animal or human. By immobilization of specific antigenic structures, infections with Herpes simplex and human immunodeficiency viruses, Salmonella and Treponema pallidum bacteria, and Schistosoma spp. parasites were revealed using human, avian, and porcine sera and avian eggs. Bound antibodies were easily isotyped using an SPR biosensor to reveal the infection history of the individual. Discussed studies show the recent recognition of the suitability of this type of instrument for (rapid) detection of health-threatening microbes to food and environmental microbial safety.

Biosensing Techniques↗
PubMed2006

[Prevalence of putative periodontal microorganisms in Chinese patients with aggressive periodontitis].

OBJECTIVE: To evaluate the prevalence of putative periodontal microorganism in Chinese patients with aggressive periodontitis (AgP). METHODS: A total of 72 subgingival plaque samples were collected from 55 AgP patients and 17 healthy subjects. Seven putative periodontal microorganisms including Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema denticola (Td), Campylobacter rectus (Cr), Prevotella intermedia (Pi) and Prevotella nigrescens (Pn) were detected by using 16S rRNA based polymerase chain reaction (PCR). RESULTS: The prevalence of Aa in AgP patients was very low (1.8%), while Pg, Tf, Td and Cr were more frequently detected in AgP patients (prevalence: 81.8%, 83.6%, 80% and 81.8%) than in healthy controls (prevalence: 17.6%, 11.8%, 5.9%, 29.4%, P < 0.01). CONCLUSIONS: The prevalence of Pg, Tf, Td and Cr were very high in aggressive periodontitis patients, and the combination of these bacteria may play an important role in AgP.

Adolescent↗
PubMed2006

The isolation of microorganisms capable of phenol degradation.

The results of a study on the composition of microflora settling the pilot biofilter bed that purifies the exhausting gases from a cable factory's coil-wire varnishing division are presented in this study. The ability of isolated bacterial strains to biodegrade phenol was also evaluated using culture media of various compositions. Phenol was introduced into the medium at the following concentrations: 0.25, 0.5, 0.75 and 1 g x dm(-3). In addition, air in desiccators, where micro-organisms grew, was saturated with phenol. The isolated microorganisms were graded by the phenol decomposition rate using gas chromatography. The beds of biofilters utilized in industry appeared to be the source of microorganisms capable of degrading phenol. The most active were: Rhodococcus rhodochrous, Gordonia sputi, Pseudomonas putida. Their mixture showed higher degradation activity than the particular isolates. Isolated and identified bacteria metabolized phenol at high rate (about 14 to 42 g x m(-3) x h(-3)).

Air Pollutants↗
PubMed2006

Melanin synthesis in microorganisms--biotechnological and medical aspects.

Melanins form a diverse group of pigments synthesized in living organisms in the course of hydroxylation and polymerization of organic compounds. Melanin production is observed in all large taxa from both Pro- and Eukaryota. The basic functions of melanins are still a matter of controversy and speculation, even though their adaptative importance has been proved. Melanogenesis has probably evolved parallel in various groups of free living organisms to provide protection from environmental stress conditions, but in pathogenic microorganisms it correlates with an increased virulence. The genes responsible for melanization are collected in some cases within operons which find a versatile application in genetic engineering. This review summarizes current views on melanogenesis in Pro- and Eukaryotic microorganisms in terms of their biotechnological and biomedical importance.

Animals↗
PubMedDate not supplied

Effect of some essential oils on microorganisms.

The essential oils tested viz., Cardiaca Oil, Mentha Oil, Artemisia Oil and Geranium Oil against pathogenic bacterial and fungal strains. Significant activity of all oils was found against all microorganisms. All the four oils showed a higher inhibition against all the microorganisms, except S. epidermidis at different level of concentrations used (1000 ppm and 500 ppm). It is clearly indicated that inhibition activity increased approximately 1 to 2 folds at 1000 ppm concentration as compared to 500 ppm. S. epidermidis has shown resistant towards all the oils at both the concentration while M. smegmatis and S. mutans have shown higher inhibition as compared to S. epidermidis.

Aspergillus niger↗
PubMed2006

Ultrastructure and transovarial transmission of endosymbiotic microorganisms in Palaeococcus fuscipennis (Burmeister) (Insecta, Hemiptera, Coccinea: Monophlebidae).

Ovaries ofPalaeococcus fuscipennis (Burmeister) are accompanied by large organs termed bacteriomes which are composed of large cells termed bacteriocytes. Each bacteriocyte is surrounded with small epithelial cells. The bacteriocyte cytoplasm is tightly packed with pleomorphic bacteria, whereas in epithelial cells small coccoid microorganisms are present. The number of coccoid bacteria is significantly lower than pleomorphic bacteria. The ovarioles containing choriogenic oocytes are invaded both by pleomorphic as well by coccoid bacteria. Microorganisms traverse the follicular epithelium and enter the perivitelline space. During advanced choriogenesis, endosymbionts are accumulated in the deep depression of the oocyte. Bacteria do not enter the ooplasm until the end of oocyte growth.

Animals↗