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Microbiological Research Apr 2015The aim of this work was to clarify the mechanism related to plant growth promoting of a bacterial strain (L115) isolated from Arachis hypogaea rhizospheres and the...
The aim of this work was to clarify the mechanism related to plant growth promoting of a bacterial strain (L115) isolated from Arachis hypogaea rhizospheres and the effects of high growth temperature and salinity on phospholipids and fatty acids composition. L115 was isolated from peanut rhizospheres and identified according to the sequence analysis of the 16S rRNA gene. Phenotypic, metabolic and plant growth promoting rhizobacteria (PGPR) characteristics of L115 were tested. Inoculation test in plant growth chamber was performed. In addition, L115 was exposed to a 37 °C and 300 mM NaCl and phospholipids and fatty acid composition were evaluated. L115 strain was identified as Ochrobactrum intermedium and was able to increase the peanut shoot and root length as well as dry weight, indicating a PGPR role by being able to produce indole acetic acid and siderophores and present ACC deaminase activity. In addition, L115 showed tolerance to both high growth temperature and 300 mM NaCl. The most striking change was a decreased percentage of 18:1 fatty acid and an increase in 16:0 and 18:0 fatty acids, under high growth temperature or a combination of increased temperature and salinity. The most important change in phospholipid levels was an increase in phosphatidylcholine biosynthesis in all growth conditions. L115 can promote the growth of peanut and can tolerate high growth temperature and salinity modifying the fatty acid unsaturation degree and increasing phosphatidylcholine levels. This work is the first to report the importance of the genus Ochrobactrum as PGPR on peanut growth as well as on the metabolic behaviour against abiotic stresses that occur in soil. This knowledge will be useful for developing strategies to improve the growth of this bacterium under stress and to enhance its bioprocess for the production of inoculants.
Topics: Arachis; Argentina; Indoleacetic Acids; Lipid Metabolism; Lipids; Molecular Sequence Data; Ochrobactrum; Phylogeny; Rhizosphere; Salinity; Sodium Chloride; Soil; Soil Microbiology; Temperature
PubMed: 25801965
DOI: 10.1016/j.micres.2014.12.012 -
Veterinary Immunology and... Jan 2015Current serological tests for swine brucellosis detect antibodies to the Brucella O-polysaccharide (O/PS). However, when infections by bacteria carrying cross-reacting...
Current serological tests for swine brucellosis detect antibodies to the Brucella O-polysaccharide (O/PS). However, when infections by bacteria carrying cross-reacting O/PS occur, these tests suffer from false positive serological reactions (FPSR), and the skin test with Brucella soluble protein extracts is the best diagnostic alternative to differentiate true Brucella suis infections from FPSR in pigs. Since this test has been seldom used in B. suis infected swine, the clinical and histological features involved have not been described properly. Here, we describe the clinical and histological events in B. suis biovar 2 infected pigs skin tested with a cytosoluble O/PS free protein extract from rough Brucella abortus Tn5::per mutant. A similar extract from rough Ochrobactrum intermedium was also used for comparative purposes. No relevant differences were evidenced between the homologous and heterologous allergens, and the main clinical feature was an elevated area of the skin showing different induration degrees. Moreover, an important vascular reaction with hyperemia and haemorrhage was produced in most infected sows 24-48 h after inoculation, thus facilitating the clinical interpretation of positive reactions. Histologically, combined immediate (type III) and delayed (type IV) hypersensitivity reactions were identified as the most relevant feature of the inflammatory responses produced.
Topics: Animals; Antigens, Bacterial; Brucella abortus; Brucella suis; Brucellosis; Cross Reactions; False Positive Reactions; Female; Gram-Negative Bacterial Infections; Ochrobactrum; Skin; Skin Tests; Swine; Swine Diseases
PubMed: 25480681
DOI: 10.1016/j.vetimm.2014.11.009 -
FEMS Microbiology Letters Oct 2014We report draft genome sequence of Ochrobactrum intermedium strain 229E concurrent with Helicobacter pylori in urease positive gastric biopsy of non-ulcer dyspeptic...
We report draft genome sequence of Ochrobactrum intermedium strain 229E concurrent with Helicobacter pylori in urease positive gastric biopsy of non-ulcer dyspeptic individual from Southern part of India. Since the role of Ochrobactrum in human gastric environment is poorly understood, comprehensive pathological, microbiological, and genome level understanding are necessary to evaluate its association with H. pylori in the gastric niche. Comparative analysis of O. intermedium 299E strain revealed functional similarities with virulence related gene clusters present in H. pylori genomes, which probably might aid in its ability to persist in the human gastric mucosa. However, H.pylori specific vacuolating cytotoxin (vacA) involved in vacuolization, cytotoxicity, and T-cell inhibition was absent in the O. intermedium 229E genome. Taken together, O. intermedium 229E shared numerous features like secretion system, urease, and flagella with H.pylori genome sequence that might aid concurrence in the gastric niche.
Topics: DNA, Bacterial; Genome, Bacterial; India; Molecular Sequence Data; Ochrobactrum; Sequence Analysis, DNA; Stomach
PubMed: 25312622
DOI: 10.1111/1574-6968.12549 -
Brazilian Journal of Microbiology :... 2014Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up....
Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up. The stress effect of variable chromate levels, pHs and growth temperatures on biochemical parameters of two Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 was investigated. Transmission electrone microscopy (TEM) was performed to study the intracellular distribution of Cr(VI). It was observed that initial stress of 1000 μgmL(-1) caused significant enhancement of all studied biochemical parameters at pH 7.0 and growth temperature of 37 °C showing great bioremediation potential of the strains. Transmission electron microscopy revealed that the distribution of chromium precipitates was not uniform as they were distributed in the cytoplasm as well as found associated with the periplasm and outer membrane. Fourier transform infrared spectroscopy showed the possible involvement of carboxyl, amino, sulpohonate and hydroxyl groups present on the bacterial cell surface for the binding of Cr(VI) ions. Cr(VI) stress brought about changes in the distridution of these functional groups. It can be concluded that the investigated bacterial strains adjust well to Cr(VI) stress in terms of biochemical parameters and along that exhibited alteration in morphology.
Topics: Chromium; Cytoplasm; Environmental Pollutants; Hydrogen-Ion Concentration; Microscopy, Electron, Transmission; Ochrobactrum; Oxidation-Reduction; Pseudomonas aeruginosa; Spectroscopy, Fourier Transform Infrared; Stress, Physiological; Surface Properties; Temperature
PubMed: 25242944
DOI: 10.1590/s1517-83822014000200028 -
PloS One 2014To provide a basis for using indigenous bacteria for bioremediation of heavy metal contaminated soil, the heavy metal resistance and plant growth-promoting activity of...
To provide a basis for using indigenous bacteria for bioremediation of heavy metal contaminated soil, the heavy metal resistance and plant growth-promoting activity of 136 isolates from V-Ti magnetite mine tailing soil were systematically analyzed. Among the 13 identified bacterial genera, the most abundant genus was Bacillus (79 isolates) out of which 32 represented B. subtilis and 14 B. pumilus, followed by Rhizobium sp. (29 isolates) and Ochrobactrum intermedium (13 isolates). Altogether 93 isolates tolerated the highest concentration (1000 mg kg(-1)) of at least one of the six tested heavy metals. Five strains were tolerant against all the tested heavy metals, 71 strains tolerated 1,000 mg kg(-1) cadmium whereas only one strain tolerated 1,000 mg kg(-1) cobalt. Altogether 67% of the bacteria produced indoleacetic acid (IAA), a plant growth-promoting phytohormone. The concentration of IAA produced by 53 isolates was higher than 20 µg ml(-1). In total 21% of the bacteria produced siderophore (5.50-167.67 µg ml(-1)) with two Bacillus sp. producing more than 100 µg ml(-1). Eighteen isolates produced both IAA and siderophore. The results suggested that the indigenous bacteria in the soil have beneficial characteristics for remediating the contaminated mine tailing soil.
Topics: Bacillus; Bacteria; Metals, Heavy; Mining; Ochrobactrum; Plant Development; Rhizobium; Siderophores; Soil Microbiology
PubMed: 25188470
DOI: 10.1371/journal.pone.0106618 -
Research in Veterinary Science Oct 2014The effects of the lipopolysaccharide (LPS) from Ochrobactrum intermedium in sheep with fasciolosis was reported previously, resulting in lower fecal egg counts and...
The effects of the lipopolysaccharide (LPS) from Ochrobactrum intermedium in sheep with fasciolosis was reported previously, resulting in lower fecal egg counts and fluke burden. In the current study, we analyzed its immunological effects in two groups of sheep, treated (T) and controls (C). Fasciolosis induces a T helper (Th) type-2 response, characterized by IL-4 and IL-10 production; however, at the beginning of the infection, the IFN-γ production predominates (Th type-1 response). Although we did not find differences in IL-4 production or in the expression level of this gene in the hepatic lymph nodes, the expression level of IL-10 was higher (P < 0.05) in the T group at 4 wpi. The IFN-γ production was higher (P < 0.01) at 12 wpi as well as its level of expression at 4 wpi (P < 0.05) in the T group. We found a higher expression level of TGF-β at 4 wpi in the T group (P < 0.05), associated with the previous report of thicker fibrous tracks in a treated group. Immunoglobulin G1, related with a Th type-2 response, was higher (P < 0.01) in the T group at 4 and 12 wpi. In conclusion, the effects of LPS from O. intermedium could have resulted from a predominant Th type-2 immune response.
Topics: Animals; Fasciola hepatica; Fascioliasis; Feces; Immunoglobulin G; Interferon-gamma; Interleukin-10; Interleukin-4; Lipopolysaccharides; Ochrobactrum; Sheep; Sheep Diseases; Th2 Cells; Transforming Growth Factor beta
PubMed: 25151434
DOI: 10.1016/j.rvsc.2014.07.015 -
Environmental Technology 2014Microbial fuel cells (MFCs) have attracted considerable attention as potential biosensors. A MFC biosensor for rapid measurement of biochemical oxygen demand (BOD) has...
Microbial fuel cells (MFCs) have attracted considerable attention as potential biosensors. A MFC biosensor for rapid measurement of biochemical oxygen demand (BOD) has been recently studied. However, a standardized bacterial mixture inoculated in the MFC biosensor for BOD measurement is unavailable. Thus, the commercial application of a MFC biosensor is limited. In this study, a mediator-less MFC biosensor inoculated with known mixed cultures to quickly determine BOD concentration was tested. Optimal external resistance, operating temperature and measurement time for the MFC biosensor were determined to be 5000 omega, 35 degrees C and 12h, respectively. A good relationship between BOD concentration and voltage output, high reproducibility and long-term stability for the MFC biosensor was observed. The newly developed MFC biosensor was inoculated with a mixture of six bacterial strains (Thermincola carboxydiphila, Pseudomonas aeruginosa, Ochrobactrum intermedium, Shewanella frigidimarina, Citrobacter freundii and Clostridium acetobutylicum) capable of degrading complex organic compounds and surviving toxic conditions. The described MFC biosensor was able to successfully measure BOD concentrations below 240 mg L(-1) in real wastewater samples.
Topics: Bioelectric Energy Sources; Biological Oxygen Demand Analysis; Biosensing Techniques; Oxygen; Temperature; Wastewater
PubMed: 25145173
DOI: 10.1080/09593330.2014.898700 -
Journal of Hazardous Materials Aug 2014In real environmental applications, such as heavy metal bioremediation, microorganisms are generally not kept at their optimum growth conditions; therefore, it is...
In real environmental applications, such as heavy metal bioremediation, microorganisms are generally not kept at their optimum growth conditions; therefore, it is imperative to investigate their heavy metal removal performance under diverse environmental conditions. The present study aims to investigate the effects of pH, temperature and growth phases on the removal of Cu(2+) and Cr(6+) by two environmental isolates identified as Ochrobactrum intermedium LBr and Cupriavidus metallidurans CH34. Results showed that cells in logarithmic phase presented better biosorption capacity than cells in stationary phase for both isolates. The Cr(6+) metal was removed more efficiently by live O. intermedium LBr than dead cells; while dead C. metallidurans CH34 biosorbed better than live ones. It was also found that the pH and temperature affected the biosorption capacity. The optimum temperatures were determined to be 37°C and 27°C, and the optimum pH values were 6 and 7 for O. intermedium LBr and C. metallidurans CH34, respectively. Additionally, both microorganisms preferentially adsorbed Cu(2+) in Cu(2+)/Cr(6+) mixtures. The main mechanism of adsorption was determined to be through carboxylic, hydroxyl, and amino functional groups.
Topics: Biodegradation, Environmental; Biomass; Chromium Compounds; Copper; Cupriavidus; Hydrogen-Ion Concentration; Metals, Heavy; Microbial Sensitivity Tests; Ochrobactrum; Temperature; Thermodynamics
PubMed: 25064261
DOI: 10.1016/j.jhazmat.2014.07.016 -
Parasites & Vectors Jul 2014Phlebotomine sand flies transmit the haemoflagellate Leishmania, the causative agent of human leishmaniasis. The Leishmania promastigotes are confined to the gut lumen...
BACKGROUND
Phlebotomine sand flies transmit the haemoflagellate Leishmania, the causative agent of human leishmaniasis. The Leishmania promastigotes are confined to the gut lumen and are exposed to the gut microbiota within female sand flies. Here we study the colonisation resistance of yeast and bacteria in preventing the establishment of a Leishmania population in sand flies and the ability of Leishmania to provide colonisation resistance towards the insect bacterial pathogen Serratia marcescens that is also pathogenic towards Leishmania.
METHODS
We isolated microorganisms from wild-caught and laboratory-reared female Lutzomyia longipalpis, identified as Pseudozyma sp. Asaia sp. and Ochrobactrum intermedium. We fed the females with a sugar meal containing the microorganisms and then subsequently fed them with a bloodmeal containing Leishmania mexicana and recorded the development of the Leishmania population. Further experiments examined the effect of first colonising the sand fly gut with L. mexicana followed by feeding with, Serratia marcescens, an insect bacterial pathogen. The mortality of the flies due to S. marcescens was recorded in the presence and absence of Leishmania.
RESULTS
There was a reduction in the number of flies harbouring a Leishmania population that had been pre-fed with Pseudozyma sp. and Asaia sp. or O. intermedium. Experiments in which L. mexicana colonised the sand fly gut prior to being fed an insect bacterial pathogen, Serratia marcescens, showed that the survival of flies with a Leishmania infection was significantly higher compared to flies without Leishmania infection.
CONCLUSIONS
The yeast and bacterial colonisation experiments show that the presence of sand fly gut microorganisms reduce the potential for Leishmania to establish within the sand fly vector. Sand flies infected with Leishmania were able to survive an attack by the bacterial pathogen that would have killed the insect and we concluded that Leishmania may benefit its insect host whilst increasing the potential to establish itself in the sand fly vector. We suggest that the increased ability of the sand fly to withstand a bacterial entomopathogen, due to the presence of the Leishmania, may provide an evolutionary pressure for the maintenance of the Leishmania-vector association.
Topics: Animals; Female; Host-Pathogen Interactions; Leishmania; Psychodidae; Serratia
PubMed: 25051919
DOI: 10.1186/1756-3305-7-329