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Microbial Ecology Nov 2019A resumption of climate warming in maritime Antarctica, arising from continued greenhouse gas emissions to the atmosphere, is predicted to lead to further expansions of...
A resumption of climate warming in maritime Antarctica, arising from continued greenhouse gas emissions to the atmosphere, is predicted to lead to further expansions of plant populations across the region, with consequent increases in nutrient inputs to soils. Here, we test the main and interactive effects of warming, applied with open top chambers (OTCs), and nutrient amendment with tryptic soy broth (TSB), an artificial growth substrate, on bacterial community composition and diversity using Illumina sequencing of 16S rRNA genes in soil from a field experiment in the southern maritime Antarctic. Substantial effects of TSB application on bacterial communities were identified after 49 months, including reduced diversity, altered phylogenetic community assembly processes, increased Proteobacteria-to-Acidobacteria ratios and significant divergence in community composition, notably increases in the relative abundances of the gram-positive genera Arthrobacter, Paeniglutamicibacter and Planococcus. Contrary to previous observations from other maritime Antarctic field warming experiments, we recorded no effects of warming with OTCs, or interactive effects of OTCs and TSB application, on bacterial community composition or diversity. Based on these findings, we conclude that further warming of the maritime Antarctic is unlikely to influence soil bacterial community composition or diversity directly, but that increased nutrient inputs arising from enhanced plant growth across the region may affect the composition of soil bacterial communities, with possible effects on ecosystem productivity.
Topics: Antarctic Regions; Bacteria; Bacterial Physiological Phenomena; Fertilizers; Global Warming; Hot Temperature; Microbiota; RNA, Bacterial; RNA, Ribosomal, 16S; Soil Microbiology
PubMed: 30989354
DOI: 10.1007/s00248-019-01373-z -
Frontiers in Microbiology 2019Moderate halophilic bacteria thrive in saline conditions and produce biosurfactant (BS) which facilitates the oil scavenging activity in the oil polluted surroundings....
Moderate halophilic bacteria thrive in saline conditions and produce biosurfactant (BS) which facilitates the oil scavenging activity in the oil polluted surroundings. Production of such unusual bioactive molecules plays a vital role for their survival in an extreme and adverse environment. Current research deals with isolation of strain SAMP MCC 3013 from Indian Arabian coastline sea water for BS production. The bacterium tolerated up to 2.7 M NaCl demonstrating osmotic stress bearable physiological systems. We used integrated approach to explore the genomic insight of the strain SAMP and displayed the presence of gene for BS biosynthesis. The genome analysis revealed this potential to be intrinsic to the strain. Preliminary screening techniques viz., surface tension (SFT), drop collapse (DC) and oil displacement (OD) showed SAMP MCC 3013 as a potent BS producer. BS reduced SFT of phosphate buffer saline (PBS) pH: 7.0 from 72 to 30 mN/m with a critical micelle concentration (CMC) value of 1.3 mg/mL. Subsequent investigation on chemical characterization, using thin layer chromatography (TLC), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (H NMR and C NMR) and liquid chromatography mass spectrometry (LC-MS) revealed terpene containing BS having sugar, lipid moieties. The genomic sequence analysis of SAMP showed complete genes in the pathway for the synthesis of terpenoid. Probably terpenoid is the accountable backbone molecule for the BS production, but the later stages of terpenoid conversion to the BS could not be found. Moreover, it is important to highlight that till today; no single report documents the in-detailed physico-chemical characterization of BS from sp. Based on genomic and functional properties, the term terpene containing BS is denoted for the surfactant produced by .
PubMed: 30863371
DOI: 10.3389/fmicb.2019.00235 -
Ecology and Evolution Feb 2019Associations between Sternorrhyncha insects and intracellular bacteria are common in nature. Mealybugs are destructive pests that seriously threaten the production of...
Associations between Sternorrhyncha insects and intracellular bacteria are common in nature. Mealybugs are destructive pests that seriously threaten the production of agriculture and forestry. Mealybugs have evolved intimate endosymbiotic relationships with bacteria, which provide them with essential amino acids, vitamins, and other nutrients. In this study, the divergence of five mealybugs was analyzed based up the sequences of the mitochondrial cytochrome oxidase I (mtCOI). Meanwhile, the distinct regions of the 16S rRNA gene of primary symbionts in the mealybugs were sequenced. Finally, high-throughput sequencing (HTS) techniques were used to study the microbial abundance and diversity in mealybugs. Molecular phylogenetic analyses revealed that these five mealybugs were subdivided into two different clusters. One cluster of mealybugs (, , and ) harbored the primary endosymbiont " Tremblaya princeps," and another cluster ( and ) harbored ". Tremblaya phenacola." The mtCOI sequence divergence between the two clusters was similar to the 16S rRNA sequence divergence between and . Thus, we concluded that the symbiont phylogeny was largely concordant with the host phylogeny. The HTS showed that the microbial abundance and diversity within and were highly similar, and there was lower overall species richness compared to the other mealybugs. Among the five mealybugs, we also found significant differences in Shannon diversity and observed species. These results provide a theoretical basis for further research on the coevolution of mealybugs and their symbiotic microorganisms. These findings are also useful for research on the effect of symbiont diversity on the pest status of mealybugs in agricultural systems.
PubMed: 30847086
DOI: 10.1002/ece3.4889 -
Journal, Genetic Engineering &... Dec 2018Marine environments are substantially untapped source for the isolation of bacteria with the capacity to produce various extracellular hydrolytic enzymes, which have...
Marine environments are substantially untapped source for the isolation of bacteria with the capacity to produce various extracellular hydrolytic enzymes, which have important ecological roles and promising biotechnological applications. Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. A number of marine hydrolases have been described, including amylases, lipases and proteases, which are being used extensively for biotechnological applications. The present study was carried out to isolate marine bacteria from continental slope sediments of the eastern Arabian Sea and explore their biotechnological potential. Among the 119 isolates screened, producers of amylases (15%), caseinases (40%), cellulases (40%), gelatinases (60%), lipases (26%), ligninases (33%), phytase (11%) and Malachite Green dye degraders (16%) were detected. Phylogenetic analysis based on 16S rRNA gene sequencing showed that predominant marine sediment bacteria possessing more than four enzymatic activities belonged to the phyla Firmicutes and Proteobacteria, was assigned to the genera and Biodegradation of the dye Malachite Green using the liquid decolorization assay showed that both the individual cultures () and their consortium were able to decolorize more than 70% of dye within 24 h of incubation. This is the first report on diversity and extracellular hydrolytic enzymatic activities and bioremediation properties of bacteria from continental slope sediment of eastern Arabian Sea.
PubMed: 30733732
DOI: 10.1016/j.jgeb.2018.06.002 -
Biotechnology Reports (Amsterdam,... Mar 2019Carotenoids are isoprenoid pigments used by pharmaceutical, cosmetic, food and feed industry as antioxidants and colorants. Although traditional sources of carotenoids...
Carotenoids are isoprenoid pigments used by pharmaceutical, cosmetic, food and feed industry as antioxidants and colorants. Although traditional sources of carotenoids are fruits, vegetables and chemical synthesis, prospecting for alternative sinks of common and/or unusual carotenoids is important for the development of natural carotenoid industry. In this work, 30 pigmented bacterial strains from Fildes Peninsula in King George Island, Antarctica, were isolated and identified by 16S rRNA gene sequencing and classified in three phyla, Bacteroidetes, Firmicutes and Actinobacteria. After cells extraction, ten different carotenoids were identified based on the chromatographic and spectroscopic characteristic obtained by HPLC-PDA and HPLC-PDA-APCI-MS analyses. Strains assigned to Bacteroidetes affiliated to and genera, presented a pigment profile composed of zeaxanthin, β-cryptoxanthin and β-carotene. Firmicutes strains of genus produced a C50 carotenoid, identified as C.p. 450 glucoside. Actinobacteria isolates were mainly assigned to genus, and few to and genera. strains produced C50 carotenoids such as decaprenoxanthin and its glucosylated derivatives, as well as some C40 carotenoids such as lycopene which is used as synthesis precursors of the C50 carotenoids. and genera produced C.p. 450 free form and its glucosylated derivatives. Although most isolates produce carotenoids similar in diversity and quantity than those already reported in the literature, novel sources for C50 carotenoids results from this work. According to their carotenoid content, all isolates could be promising candidates for carotenoids production.
PubMed: 30705834
DOI: 10.1016/j.btre.2019.e00306 -
Microbial Cell Factories Nov 2018N-acylhomoserine lactones (AHLs) are well-studied signalling molecules produced by some Gram-negative Proteobacteria for bacterial cell-to-cell communication or quorum...
BACKGROUND
N-acylhomoserine lactones (AHLs) are well-studied signalling molecules produced by some Gram-negative Proteobacteria for bacterial cell-to-cell communication or quorum sensing. We have previously demonstrated the degradation of AHLs by an Antarctic bacterium, Planococcus versutus L10.15, at low temperature through the production of an AHL lactonase. In this study, we cloned the AHL lactonase gene and characterized the purified novel enzyme.
RESULTS
Rapid resolution liquid chromatography analysis indicated that purified AidP possesses high AHL-degrading activity on unsubstituted, and 3-oxo substituted homoserine lactones. Liquid chromatography-mass spectrometry analysis confirmed that AidP functions as an AHL lactonase that hydrolyzes the ester bond of the homoserine lactone ring of AHLs. Multiple sequence alignment analysis and phylogenetic analysis suggested that the aidP gene encodes a novel AHL lactonase enzyme. The amino acid composition analysis of aidP and the homologous genes suggested that it might be a cold-adapted enzyme, however, the optimum temperature is 28 °C, even though the thermal stability is low (reduced drastically above 32 °C). Branch-site analysis of several aidP genes of Planococcus sp. branch on the phylogenetic trees also showed evidence of episodic positive selection of the gene in cold environments. Furthermore, we demonstrated the effects of covalent and ionic bonding, showing that Zn is important for activity of AidP in vivo. The pectinolytic inhibition assay confirmed that this enzyme attenuated the pathogenicity of the plant pathogen Pectobacterium carotovorum in Chinese cabbage.
CONCLUSION
We demonstrated that AidP is effective in attenuating the pathogenicity of P. carotovorum, a plant pathogen that causes soft-rot disease. This anti-quorum sensing agent is an enzyme with low thermal stability that degrades the bacterial signalling molecules (AHLs) that are produced by many pathogens. Since the enzyme is most active below human body temperature (below 28 °C), and lose its activity drastically above 32 °C, the results of a pectinolytic inhibition assay using Chinese cabbage indicated the potential of this anti-quorum sensing agent to be safely applied in the field trials.
Topics: 4-Butyrolactone; Amino Acid Sequence; Antarctic Regions; Bacterial Proteins; Carboxylic Ester Hydrolases; Models, Molecular; Pectins; Pectobacterium carotovorum; Planococcus Bacteria; Quorum Sensing; Sequence Analysis, Protein; Substrate Specificity
PubMed: 30445965
DOI: 10.1186/s12934-018-1024-6 -
Acta Crystallographica. Section F,... Nov 2018The determination of conditions for the reproducible growth of well diffracting crystals is a critical step in every biocrystallographic study. On the occasion of a new...
The determination of conditions for the reproducible growth of well diffracting crystals is a critical step in every biocrystallographic study. On the occasion of a new structural biology project, several advanced crystallogenesis approaches were tested in order to increase the success rate of crystallization. These methods included screening by microseed matrix screening, optimization by counter-diffusion and crystal detection by trace fluorescent labeling, and are easily accessible to any laboratory. Their combination proved to be particularly efficient in the case of the target, a 48 kDa CCA-adding enzyme from the psychrophilic bacterium Planococcus halocryophilus. A workflow summarizes the overall strategy, which led to the production of crystals that diffracted to better than 2 Å resolution and may be of general interest for a variety of applications.
Topics: Bacterial Proteins; Crystallization; Crystallography, X-Ray; Escherichia coli; Planococcus Bacteria; RNA Nucleotidyltransferases; Recombinant Proteins; Workflow
PubMed: 30387781
DOI: 10.1107/S2053230X18014590 -
Standards in Genomic Sciences 2018Y42, isolated from the petroleum-contaminated soil of the Qaidam Basin, can use crude oil as its sole source of carbon and energy at 20 °C. The genome of strain Y42...
Y42, isolated from the petroleum-contaminated soil of the Qaidam Basin, can use crude oil as its sole source of carbon and energy at 20 °C. The genome of strain Y42 has been sequenced to provide information on its properties. Genomic analysis shows that the genome of strain Y42 contains one circular DNA chromosome with a size of 3,718,896 bp and a GC content of 48.8%, and three plasmids (329,482; 89,073; and 12,282 bp). Although the strain Y42 did not show a remarkably higher ability in degrading crude oil than other oil-degrading bacteria, the existence of strain Y42 played a significant role to reducing the overall environmental impact as an indigenous oil-degrading bacterium. In addition, genome annotation revealed that strain Y42 has many genes responsible for hydrocarbon degradation. Structural features of the genomes might provide a competitive edge for strain Y42 to survive in oil-polluted environments and be worthy of further study in oil degradation for the recovery of crude oil-polluted environments.
PubMed: 30338026
DOI: 10.1186/s40793-018-0328-9 -
Preparative Biochemistry & Biotechnology 2018The objective was to evaluate the anticancer and antioxidant activities of the methanolic extracts of halophilic bacteria, isolated from soil samples of Marakkanam...
Evaluation of the anti-oxidant property and cytotoxic potential of the metabolites extracted from the bacterial isolates from mangrove Forest and saltern regions of South India.
The objective was to evaluate the anticancer and antioxidant activities of the methanolic extracts of halophilic bacteria, isolated from soil samples of Marakkanam saltern and Pichavaram mangrove forest, India. Radical Scavenging activity, reducing power, and metal ion chelation ability was used to evaluate the antioxidant potential of the metabolic extracts, whereas cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The methanolic extract of Bacillus VITPS7 exhibited significant antioxidant property. Bacillus VITPS14 and Bacillus VITPS16 extracts were cytotoxic against HeLa cell lines but not to A549 cell lines. Colorimetric assays for the presence of specific metabolites including, total flavonoid and β carotene content were performed. The presence of these specific classes of metabolites was confirmed by UV-Visible spectrophotometry, Nuclear Magnetic Resonance (NMR) spectroscopy and Gas Chromatography-Mass Spectrometry (GC-MS). Specific NMR signals revealed the presence of aromatic and unsaturated metabolites whereas GC-MS analysis indicated the presence of metabolites such as squalene and methyl hexadeconate. The present study thus reports for the first time the presence of squalene in Bacillus VITPS12 and Planococcus maritimus VITP21, in addition to other metabolites that contribute to the observed antioxidant or/and cytotoxicity, thus revealing the therapeutic potential of these selected halophilic bacterial isolates.
Topics: Antineoplastic Agents; Antioxidants; Bacillus; Cytotoxins; HeLa Cells; Humans; India; Wetlands
PubMed: 30303456
DOI: 10.1080/10826068.2018.1508038 -
Microbial Biotechnology Mar 2019The disposal of reject brine, a highly concentrated waste by-product generated by various industrial processes, represents a major economic and environmental challenge....
The disposal of reject brine, a highly concentrated waste by-product generated by various industrial processes, represents a major economic and environmental challenge. The common practice in dealing with the large amounts of brine generated is to dispose of it in a pond and allow it to evaporate. The rate of evaporation is therefore a key factor in the effectiveness of the management of these ponds. The addition of various dyes has previously been used as a method to increase the evaporation rate. In this study, a biological approach, using pigmented halophilic bacteria (as opposed to chemical dyes), was assessed. Two bacteria, an Arthrobacter sp. and a Planococcus sp. were selected due to their ability to increase the evaporation of synthetic brine. When using industrial brine, supplementation of the brine with an iron source was required to maintain the pigment production. Under these conditions, the Planococcus sp. CP5-4 produced a carotenoid-like pigment, which resulted in a 20% increase in the evaporation rate of the brine. Thus, the pigment production capability of halophilic bacteria could potentially be exploited as an effective step in the management of industrial reject brines, analogous to the crystallizer ponds used to mine salt from sea water.
Topics: Arthrobacter; Biotechnology; Iron; Pigments, Biological; Planococcus Bacteria; Salts; Waste Disposal, Fluid; Water Purification
PubMed: 30277309
DOI: 10.1111/1751-7915.13319