Microbial Communities in Long-Term, Water-Flooded Petroleum Reservoirs with Different in situ Temperatures in the Huabei Oilfield, China

The distribution of microbial communities in the Menggulin (MGL) and Ba19 blocks in the Huabei Oilfield, China, were studied based on 16S rRNA gene analysis. The dominant microbes showed obvious block-specific characteristics, and the two blocks had substantially different bacterial and archaeal communities. In the moderate-temperature MGL block, the bacteria were mainly Epsilonproteobacteria and Alphaproteobacteria, and the archaea were methanogens belonging to Methanolinea, Methanothermobacter, Methanosaeta, and Methanocella. However, in the high-temperature Ba19 block, the predominant bacteria were Gammaproteobacteria, and the predominant archaea were Methanothermobacter and Methanosaeta. In spite of shared taxa in the blocks, differences among wells in the same block were obvious, especially for bacterial communities in the MGL block. Compared to the bacterial communities, the archaeal communities were much more conserved within blocks and were not affected by the variation in the bacterial communities

Baculovirus Capsid Display Potentiates OVA Cytotoxic and Innate Immune Responses

Baculoviruses (BV) are DNA viruses that are pathogenic for insects. Although BV infect a range of mammalian cell types, they do not replicate in these cells. Indeed, the potential effects of these insect viruses on the immune responses of mammals are only just beginning to be studied. We show in this paper that a recombinant Autographa californica multiple nuclear polyhedrosis virus carrying a fragment of ovalbumin (OVA) on the VP39 capsid protein (BV-OVA) has the capacity to act as an adjuvant and vector of antigens in mice, thereby promoting specific CD4 and cytotoxic T cell responses against OVA. BV also induced in vivo maturation of dendritic cells and the production of inflammatory cytokines, thus promoting innate and adaptive immune responses. The OVA-specific response induced by BV-OVA was strong enough to reject a challenge with OVA-expressing melanoma cells (MO5 cells) and effectively prolonged survival of MO5 bearing mice. All these findings, together with the absence of pre-existing immunity to BV in humans and the lack of viral gene expression in mammalian cells, make BV a candidate for vaccination

Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

BACKGROUND: The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. CONCLUSIONS/SIGNIFICANCE: Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general diversity patterns, despite increased mutation levels at the single-OTU level. Therefore, biofilm communities growing in sunlight exposed substrates are capable of coping with increased mutation rates and appear pre-adapted to levels of ionizing radiation in Chernobyl due to their natural adaptation to periodical desiccation and ambient UV radiation

PURIFICATION AND CHARACTERIZATION OF A NEW TRANSGLUTAMINASE FROM STREPTOMYCES SP ISOLATED IN BRAZILIAN SOIL

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A new microbial transglutaminase (MTGase or MTG, EC 2.3.2.13) from a Streptomyces sp. strain isolated from Brazilian soil samples was purified and characterized. Enzyme purification was fast and simple, consisting of two successive chromatographies on Sephadex G-75 columns with yields of 48 and 17%, respectively. The protein purification was successfully achieved to electrophoretical homogeneity on sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The molecular mass of the MTGase was estimated to be about 45 kDa. The enzyme exhibited optimal activity in the pH range of 6.0-6.5 and at 35-40C. It was stable over a broad pH range (4.5-8.0) and up to 45C. The purified MTG's activity was independent of Ca(+2), but was activated by the presence of K(+), Ba(2+), Na(+), and Co(2+), and inhibited by Cu(2+) and Hg(2+), which suggests a thiol group at its active site. The purified enzyme presented a K(m) of 6.37 mM and a V(max) of 1.7 U/mL.35413611372Food Biochemistry Laboratory of UNICAMPMicrobial Resource Division (CPQBA/UNICAMP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Laccase activity and putative laccase genes in marine-derived basidiomycetes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Studies of laccases from marine-derived fungi are limited. In the present work, putative laccase genes from three marine-derived basidiomycetes and their laccase activities were evaluated. High amounts of laccase were produced by the fungal strains Marasmiellus sp. CBMAI 1062 (971.2 U L(-1)) and Peniophora sp. CBMAI 1063 (709.03 U L(-1)) when grown for 21 d at 28 degrees C in MA2ASW medium prepared with artificial seawater. Marine-derived basidiomycetes produced multiple distinct laccase sequences of about 200 bp with 73-90% similarity to terrestrial basidiomycete laccases. Marasmiellus sp. CBMAI 1062 and Tinctoporellus sp. CBMAI 1061 showed the greatest laccase gene diversity with three and four distinct putative laccase sequences, respectively. This is the first report of laccase genes from marine-derived fungi, and our results revealed new putative laccases produced by three basidiomycetes. (C) 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.11410863872Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [05/60175-2

Isolation and characterization of alachlor-degrading actinomycetes from soil

Alachlor (2-cloro-N-(methoxymethyl)-N-(2,6-diethylphenyl)-acetamide) is an extremely toxic and highly mobile herbicide that is widely used for pre-emergence control of grasses and weeds in many commercial crops in Brazil. In order to select soil actinomycetes able to degrade this herbicide, fifty-three actinomycete strains were isolated from soil treated with alachlor using selective conditions and subjected to in vitro degradation assays. Sixteen isolates were shown to be tolerant to high concentrations of the herbicide (up to 720 mg L-1), and six of these were able to grow and degrade >= 50% alachlor (72 mg L-1) in mineral salts medium. Morphological and phylogenetic analysis enabled the assignment of the alachlor-degrading strains to the genus Streptomyces. Strain LS151 was related to the type strains of Streptomyces capoamus/Streptomyces galbus, whereas strains LS143 and LS153 were related to Streptomyces bikiniensis. The remaining strains, LS166, LS177 and LS182, were similar in morphological features and recovered in a single cluster based on 16S rDNA sequence analysis, but shown to be distinct on the, basis of genomic fingerprint data (rep-PCR). Though a definitive taxonomic assignment of alachlor-degrading strains was not possible, these data indicate that ability to degrade this pesticide was detected in different Streptomyces taxa.872818

Optimization of medium composition for transglutaminase production by a Brazilian soil Streptomyces sp.

Finding a new microbial source of transglutaminase (MTGase) and the study of the medium composition for MTGase production were the goals of this work. A total of 200 actinomycete-like strains were isolated from Brazilian soil samples and two of them named T10b and P20 were selected based on their ability to produce 0.15 U.mL(-1) and 0.25 U.mL(-1) of MTGase, respectively. Strain P20 was chosen to continue the study and was identified as Streptomyces sp. In order to optimize the MTGase activity, modifications of the usual media composition described for enzyme production were tested. The strategy adopted was: (1) screening experiment for the best carbon and nitrogen sources; (2) fractional factorial design (FFD) to elucidate the key ingredients in the media (the results indicated that the soybean flour, peptone, KH2PO4 and MgSO4.7H(2)O had a significant effect on MTGase) production and (3) central composite design (CCD) to optimize the concentration of the key components. The experimental results were fitted to a second-order polynomial model at the 95% level of significance (P < 0.05). Under the proposed optimized conditions, the model predicted a MTGase activity of 1.37 U.mL(-1), very closely matching the experimental activity of 1.4 U.mL(-1).10461862

Biodegradation of alachlor by soil streptomycetes

Streptomycetes resistant to the herbicide alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide] were used in degradation assays to characterize the products of alachlor biodegradation. Of six strains tested, Streptomyces sp. LS166, LS177, and LS182 were able to grow at an alachlor concentration of 144 mg l(-1) and degraded approximately 60-75% of the alachlor in 14 days, as evaluated by high performance liquid chromatography. The alachlor biodegradation products were identified by gas chromatography-mass spectrometry based on mass spectral data and fragmentation patterns. All compounds detected in these assays were similar for all streptomycetes strains tested, and involved dechlorination with subsequent N-dealkylation and cyclization of the remaining N-substituent with one of the ethyl groups to produce indole and quinoline derivatives. The enzymatic pathway used by Streptomyces sp. LS182 did not generate DEA (2',6'-diethylaniline), a carcinogenic derivative of alachlor reported in other studies. Given the high degradation rates observed here, the Streptomyces strains tested may be useful in the degradation/detoxification processes of alachlor.64571271