Actinomycetes isolated from Iran soil habitats were tested for the capacity to produce compounds which can protect neurons from cell death generated by oxidative stress in NT2 neurons. Confirmation ...of our initial hit was accomplished via the determination of amyloid b level using the enzyme-linked immunosorbent assay test. The most interesting amyloid b formation inhibitor discovered in our study was a secondary metabolite which was produced by strain HM45. This bioactive strain was identified as a strain of Streptomyces antibioticus DSM 40234 using polyphasic approach. The strain HM45 was deposited in Deutsche Sammlung von Mikroorganismen und Zellkulturen as S. antibioticus DSM 41955 and University of Tehran Microorganisms Sollection as S. antibioticus UTMC 00105. This work is the first report on efficiency of an actinomycete metabolite in prohibition of neurons death caused by amyloid b formation.
The causative agent of White-nose Syndrome (WNS), Pseudogymnoascus destructans, has been shown to be fatal to several species of bats in North America. To date, no compounds or chemical control ...measures have been developed which eliminates the growth of the fungus in the environment or in affected animals. In the current study, we evaluated the activity of cold-pressed, terpeneless orange oil (CPT) against multiple isolates of P. destructans in vitro. For all assays, a modified Kirby-Bauer disk diffusion assay was used. Standardized spore suspensions were prepared, adjusted to a specific optical density, and used to plate fungal lawns. Plates were incubated at either 15 degree C or 4 degree C for up to 6 months and checked at regular intervals for growth. Once controls had grown, zones of inhibition were measured (mm) on test plates and compared to those obtained using current antifungal drugs. All P. destructans isolates were completely inhibited by 100% CPT (10 ML) at 1 month of incubation regardless of temperature (4 degree C and 15 degree C). Complete inhibition persisted up to 6 months following a single exposure at this concentration. Of the standard antifungals, only amphotericin B demonstrated any activity, resulting in zone diameters ranging from 58 mm to 74 mm. CPT, at the highest concentration tested (100%), had no significant effect against a variety of other environmental organisms including various filamentous fungi, bacteria and aerobic actinomycetes. Given that CPT is relatively non-toxic, the possibility exists that the all-natural, mixture could be used as an environmental pre-treatment to eradicate P. destructans from bat habitats. Additional studies are needed to assess any undesirable effects of CPT on bat behavior and health and overall impacts on other members of the interconnected ecosystem(s).
The treatment of odorous pollutants by microorganisms on packed waste straw and cortex was investigated at the wastewater treatment plant of the Shanghai petrochemical factory. The removal efficiency ...of H2S, NH3 and VOCs (volatile organic compounds) reached 98%, 91% and 90%, respectively after operation for one month at an empty bed retention time (EBRT) of 120 s. The heterotrophic bacteria were found to be the dominant microorganism in the biofilter, while fungi and actinomycetes were also present. The bacteria were mostly identified as the members of the genus Bacillus (62.5% of cultured bacteria). The single strand conformation polymorphism (SSCP) results revealed that the genus Bacillus and Pseudomonas were the predominant bacteria. The microbial diversity gradually increased as the treatment progressed, which indicated that the microbial community in the biofilter became more stable upon pollutant removal. The scanning electron microscopy (SEM) was performed to evaluate the microorganism growth on the media. It was found that the waste straw and cortex were suitable for microorganism attachment and growth, and may have potential application in odor treatment.
Tannery effluent treated with aquatic macrophyte Vallisneria spiralis L. for 14 d showed significant improvement in physico-chemical properties and reduction in Cr concentration. Accumulation of Cr ...was found maximum in roots (358 mg g-1dw) as compared to shoot (62 mg g-1dw) of the plant. A laboratory scale composter was designed with the objectives to investigate the physico-chemical changes and role of microbes in stabilization and transformation of Cr in the composting material. Results revealed that the composting process was quick within 7-21 d as indicated by peak time for various physico-chemical parameters and drop in C/N ratio up to acceptable limit. The profile of microbial communities indicated that population of anaerobic, aerobic and nitrifying bacteria increased quickly at the initial phase, and reached a peak level of 4.2 X 106, 9.78 X 108 and 9.32 X 109 CFU g-1, respectively at 21 d; while population of actinomycetes and fungi was found maximum i.e. 3.29 X 107 and 9.7 X 106 CFU g-1, respectively, after 35 d of composting. Overall bacterial population dominated over the actinomycetes and fungi during the composting process. Cr(VI) was transformed to Cr(III) due to the microbial activity during the process. Sequential extraction of Cr fractionation showed its stabilization via changing into organic matter-bound and residual fractions during the composting.
A study was conducted at Maud T.E., Assam, India as part of FAO-CFC-TBI Project (2008-2009 to 2012-2013) to evaluate the quality of on-farm compost produced under different composting method and its ...effectivity on soil quality development. Comparative nutrient content in terms of N + P^sub 2^0^sub 5^ + K^sub 2^0 was highest in Novcom compost (3.98 %) followed by Biodynamic (3.56 %), Vermi (3.16 %) and Indigenous (2.96 %) compost. But comparative evaluation of microbial population (total bacteria, fungi, actinomycetes, ammonifiers, nitrifiers and phosphate solubilizing bacteria) in all the compost samples revealed distinctly different status of Novcom compost as compared to the rest. In case of vermi, Biodynamic and Indigenous compost, microbial population varied between 10^sup 7^ to 10^sup 12^ c.f.u., where as that of Novcom compost varied from 10^sup 12^ to 10^sup 16^ c.f.u. The comparatively high microflora population in Novcom compost could be due to its intense biodegradation process, which led to their natural generation within compost heaps.
pAL1 of the actinomycete Arthrobacter nitroguajacolicus Rue61a, a 113-kb catabolic linear megaplasmid of the invertron-type, enables its host to utilize quinaldine (or 4-hydroxyquinaldine) as the ...sole carbon and energy source. Comparative Southern hybridization and quantitative real-time PCR analyses revealed copy numbers of two for cells grown in minimal medium supplemented with 4-hydroxyquinaldine and four for cells cultivated in Luria-Bertani medium. However, medium-dependent differences in the expression levels of genes potentially involved in plasmid replication were not seen. As replication and maintenance of invertrons may depend on single-stranded DNA-binding proteins (SSBs), ORF39, the gene product of which displaying similarities to SSBs, was knocked out. However, structural stability and replication of pAL1 was not influenced. When plasmid maintenance of LB-grown wild-type cells was assessed, it was seen that after approx. 200 generations almost 80% of the cells were devoid of plasmid, indicating segregational instability of pAL1.
Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the 10 leading killer diseases in the world. At least one-quarter of the population has been infected, and there are 1.3 million ...deaths annually. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains challenges TB treatments. One of the drugs widely used in first- and second-line regimens is pyrazinamide (PZA). Statistically, 50% of MDR and 90% of XDR clinical strains are resistant to PZA, and recent studies have shown that its use in patients with PZA-resistant strains is associated with higher mortality rates. Therefore, the is an urgent need for the development of an accurate and efficient PZA susceptibility assay. PZA crosses the M. tuberculosis membrane and is hydrolyzed to its active form, pyrazinoic acid (POA), by a nicotinamidase encoded by the pncA gene. Up to 99% of clinical PZA-resistant strains have mutations in this gene, suggesting that this is the most likely mechanism of resistance. However, not all pncA mutations confer PZA resistance, only the ones that lead to limited POA production. Therefore, susceptibility to PZA may be addressed simply by its ability to form, or not, POA. Here, we present a nuclear magnetic resonance method to accurately quantify POA directly in the supernatant of sputum cultures collected from TB patients. The ability of the clinical sputum culture to hydrolyze PZA was determined, and the results were correlated with the results of other biochemical and molecular PZA drug susceptibility assays. The excellent sensitivity and specificity values attained suggest that this method could become the new gold standard for the determination of PZA susceptibility.
Aims Though plant metabolic changes are known to occur during interactions with bacteria, these were rarely challenged for pharmacologically active compounds suitable for further drug development. ...Here, the occurrence of specific chemicals with antiproliferative activity against human cancer cell lines was evidenced in hyperplasia (leafy galls) induced when plants interact with particular phytopathogens, such as the Actinomycete Rhodococcus fascians. Methods We examined leafy galls fraction F3.1.1 on cell proliferation, cell division and cytoskeletal disorganization of human cancer cell lines using time-lapse videomicroscopy imaging, combined with flow cytometry and immunofluorescence analysis. We determined the F3.1.1-fraction composition by gas chromatography coupled to mass spectrometry. Results The leafy galls induced on tobacco by R. fascians yielded fraction F3.1.1 which inhibited proliferation of glioblastoma U373 cells with an IC50 of 4.5 mu g/mL, F.3.1.1 was shown to increase cell division duration, cause nuclear morphological deformations and cell enlargement, and, at higher concentrations, karyokinesis defects leading to polyploidization and apoptosis. F3.1.1 consisted of a mixture of isomers belonging to the cembrenoids. The cellular defects induced by F3.1.1 were caused by a peculiar cytoskeletal disorganization, with the occurrence of fragmented tubulin and strongly organized microtubule aggregates within the same cell. Colchicine, paclitaxel, and cembrene also affected U373 cell proliferation and karyokinesis, but the induced microtubule rearrangement was very different from that provoked by F3.1.1. Altogether our data indicate that the cembrenoid isomers in F3.1.1 have a unique mode of action and are able to simultaneously modulate microtubule polymerization and stability.
Corynebacterium jeikeium, a resident of human skin, is often associated with multidrug resistant nosocomial infections in immunodepressed patients. C. jeikeium K411 belongs to mycolic acid-containing ...actinomycetes, the mycolata and contains a channel-forming protein as judged from reconstitution experiments with artificial lipid bilayer experiments. The channel-forming protein was present in detergent treated cell walls and in extracts of whole cells using organic solvents. A gene coding for a 40 amino acid long polypeptide possibly responsible for the pore-forming activity was identified in the known genome of C. jeikeium by its similar chromosomal localization to known porH and porA genes of other Corynebacterium strains. The gene jk0268 was expressed in a porin deficient Corynebacterium glutamicum strain. For purification temporarily histidine-tailed or with a GST-tag at the N-terminus, the homogeneous protein caused channel-forming activity with an average conductance of 1.25 nS in 1M KCl identical to the channels formed by the detergent extracts. Zero-current membrane potential measurements of the voltage dependent channel implied selectivity for anions. This preference is according to single-channel analysis caused by some excess of cationic charges located in the channel lumen formed by oligomeric alpha-helical wheels. The channel has a suggested diameter of 1.4 nm as judged from the permeability of different sized hydrated anions using the Renkin correction factor. Surprisingly, the genome of C. jeikeium contained only one gene coding for a cell wall channel of the PorA/PorH type found in other Corynebacterium species. The possible evolutionary relationship between the heterooligomeric channels formed by certain Corynebacterium strains and the homooligomeric pore of C. jeikeium is discussed.
Seven new alpha -pyrones, nocapyrones H-N (1-7) were isolated from the marine-derived actinomycete strain, Nocardiopsis dassonvilleisubsp. dassonvilleiXG-8-1. The new structures 1-7 were determined ...by spectroscopic analysis, CD spectra, ECD quantum chemical calculations and the modified Mosher's method. Compounds 1, 2 and 6 showed inhibitory effects on quorum sensing (QS) controlled gene expression in Chromobacterium violaceumCV026 and Pseudomonas aeruginosaQSIS-lasIbiosensors at a concentration of 100 mu g mL super(-1), respectively. This is the first report of inhibition of alpha -pyrones on QS controlled gene expression in pathogenic bacteria.
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