Background and aims Diazotrophic endophytic bacteria colonizing cereal plants have a tremendous scope to increase crop yields by supporting low input sustainable agricultural demands of nitrogen. ...Present work was aimed at studying diversity and functional attributes of nitrogen fixing bacterial endophytes from cereal plants. Methods Diazotrophic endophytic bacteria from cereal plants were enriched on nitrogen-free medium and their diversity analyzed by PCR-denaturing gradient gel electrophoresis. Evaluation of plant growth promoting traits of individual isolates and their effect on wheat plants was carried out in plant-soil system. Results DGGE analysis and band sequencing showed diazotrophic community to be similar in different plant parts but different than total endophytes. Thirty-one nitrogen fixing endophytic bacteria affiliated to Actinobacteria, Proteobacteria and Firmicutes representing 14 genera were isolated, where Arthrobacter, Rhizobium, and Bacillus spp. were more cosmopolitan. Cross-colonization of the endophytes monitored by green fluorescent protein tagging showed that they are not plant specific. All the bacterial isolates showed presence of nifH gene, siderophore production whereas 81% and 48% isolates showed IAA and P-solubilization, respectively. Biocontrol activity was seen only in Streptomyces spp. which inhibited the growth of Rhizoctonia solani. Pot experiments conducted with wheat plant inoculations showed good growth promotion and correlated with IAA and siderophore production by the isolates. Conclusion Diverse endophytic nitrogen fixing bacteria colonize cereal plants non-specifically and possess other plant beneficial traits which help in plant growth promotion.
Liver fibrosis is the most important predictor of mortality in nonalcoholic fatty liver disease (NAFLD). Quantitative risk of mortality by fibrosis stage has not been systematically evaluated. We ...aimed to quantify the fibrosis stage–specific risk of all‐cause and liver‐related mortality in NAFLD. Through a systematic review and meta‐analysis, we identified five adult NAFLD cohort studies reporting fibrosis stage–specific mortality (0‐4). Using fibrosis stage 0 as a reference population, fibrosis stage–specific mortality rate ratios (MRRs) with 95% confidence intervals (CIs) for all‐cause and liver‐related mortality were estimated. The study is reported according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses statement. Included were 1,495 NAFLD patients with 17,452 patient years of follow‐up. Compared to NAFLD patients with no fibrosis (stage 0), NAFLD patients with fibrosis were at an increased risk for all‐cause mortality, and this risk increased with increases in the stage of fibrosis: stage 1, MRR = 1.58 (95% CI 1.19‐2.11); stage 2, MRR = 2.52 (95% CI 1.85‐3.42); stage 3, MRR = 3.48 (95% CI 2.51‐4.83); and stage 4, MRR = 6.40 (95% CI 4.11‐9.95). The results were more pronounced as the risk of liver‐related mortality increased exponentially with each increase in the stage of fibrosis: stage 1, MRR = 1.41 (95% CI 0.17‐11.95); stage 2, MRR = 9.57 (95% CI 1.67‐54.93); stage 3, MRR = 16.69 (95% CI 2.92‐95.36); and stage 4, MRR = 42.30 (95% CI 3.51‐510.34). Limitations of the study include an inability to adjust for comorbid conditions or demographics known to impact fibrosis progression in NAFLD and the inclusion of patients with simple steatosis and nonalcoholic steatohepatitis without fibrosis in the reference comparison group. Conclusion: The risk of liver‐related mortality increases exponentially with increase in fibrosis stage; these data have important implications in assessing the utility of each stage and benefits of regression of fibrosis from one stage to another. (Hepatology 2017;65:1557‐1565).
Ultrasound has been used to non-invasively manipulate neuronal functions in humans and other animals. However, this approach is limited as it has been challenging to target specific cells within the ...brain or body. Here, we identify human Transient Receptor Potential A1 (hsTRPA1) as a candidate that confers ultrasound sensitivity to mammalian cells. Ultrasound-evoked gating of hsTRPA1 specifically requires its N-terminal tip region and cholesterol interactions; and target cells with an intact actin cytoskeleton, revealing elements of the sonogenetic mechanism. Next, we use calcium imaging and electrophysiology to show that hsTRPA1 potentiates ultrasound-evoked responses in primary neurons. Furthermore, unilateral expression of hsTRPA1 in mouse layer V motor cortical neurons leads to c-fos expression and contralateral limb responses in response to ultrasound delivered through an intact skull. Collectively, we demonstrate that hsTRPA1-based sonogenetics can effectively manipulate neurons within the intact mammalian brain, a method that could be used across species.
The Streptomyces spp. used in this work were previously isolated as diazotrophic endophytes from sorghum stems. Here, we characterized the Streptomyces spp. for their colonization ability, plant ...growth promotion and protection against fungal disease in three cereals. In vitro analysis by dual culture study showed inhibitory effect on the rice pathogen Magnaporthe oryzae B157 along with inhibition of the ubiquitous phytopathogen Rhizoctonia solani by the Streptomyces spp. used in this study. The active compounds responsible for phytopathogen inhibition were extracted with ethyl acetate and tested positive against the fungal pathogens. GC–MS based identification of the active compounds responsible for fungal pathogen inhibition showed them to be 2-(chloromethyl)-2-cyclopropyloxirane, 2, 4- ditert-butylphenol and 1‐ethylthio‐3‐methyl‐1, 3‐butadiene in extracts of culture supernatants from the three different strains respectively. EGFP tagged Streptomyces strains showed profuse colonization in roots as well as aerial parts of cereal plants. Direct inhibitory action against M. oryzae B157 and R. solani correlated with the observation that upon fungal pathogen challenge, the bacterized rice, sorghum and wheat plants showed significantly good plant growth, particularly in aerial parts as compared to unbacterized controls. In addition, benefit was seen in inoculated healthy plants in terms of increase in wet weight of roots and shoots as compared to the uninoculated controls. The mechanism of biocontrol also involved induction of plant defense response as evidenced by the upregulation of PR10a, NPR1, PAL and LOX2 in Streptomyces colonized plants.
Endophytic bacteria serve as a rich source of diverse antimicrobial compounds. Recently, there has been a growing interest in utilizing endophytic
Bacillus
spp. as biological agents against ...phytogenic fungi, owing to their potential to produce a wide range of antimicrobial substances. The objective of this research was to investigate the protective abilities of 15 endophytic
Bacillus
spp. isolated from previous study from wheat plant, against the phytopathogenic fungi,
Fusarium graminearum
and
Macrophomina phaseolina
. A dual culture plate assay was conducted as a preliminary analysis, revealing that 7 out of 15 endophytic
Bacillus
spp. demonstrated inhibition against one or both of the phytopathogenic fungi used in this study. All seven endophytes were further assessed for the presence of diffusible antifungal metabolites. The cultures were grown in potato dextrose broth for 120 h, and the cell-free supernatant was extracted and analyzed using the cup plate method. The methanolic extract yielded similar results to the dual culture plate analysis, except for WL2-15. Additionally, deformities in the mycelial structure were examined under the light microscope upon exposure to methanolic extract. Furthermore, the analysis and identification of metabolites were carried out via gas chromatography–mass spectrometry of methanolic extract from selected seven endophytic
Bacillus
spp. The chromatogram revealed the presence of some major peaks such as tridecanoic acid, methyl ester, hydroperoxide, 1-methylbutyl, 9-octadecenamide, (z)-, hexane-1,3,4-triol, 3,5-dimethyl- tetradecanoic acid. To the best of our knowledge, this is the first report of these biocontrol agents in endophytic
Bacillus
spp. Interestingly, volatile organic compound production was also seen in all the isolates against the phytopathogenic fungi.
Microbial amphiphiles play an important role in environmental activities such as microbial signaling, bioremediation, and biofilm formation. Microorganisms rely on their unique characteristics of ...interfaces to carry out critical biological functions, which are helped by amphipathic biomolecules known as amphiphiles. Bacillus amyloids aid in cell adhesion and biofilm formation. Pseudomonas sp. are essential in biofilm development and are a vital survival strategy for many bacteria. Furthermore, Pseudomonas and Bacillus are well-known for their ability to produce biosurfactants with a range of applications, including bioremediation and removing biological pollutants from different environments. The study employed 31 different media types and a range of analytical techniques to assess the presence of amyloid proteins and the absence of biosurfactants in Bacillus licheniformis K125 (GQ850525.1) and Pseudomonas fluorescens CHA0. The presence of amyloid proteins was confirmed through Congo red and thioflavin T staining. The carefully constructed medium also efficiently inhibited the synthesis of biosurfactants by these bacteria. Additionally, surface tension measurements, emulsification index, thin-layer chromatography, and high-performance thin-layer chromatography analyses indicated the absence of biosurfactants in the tested media.
•Pseudomonas and Bacillus sp. produce amphiphiles like biosurfactants and amyloid.•The growth of amyloid and biosurfactants is influenced by nutritional triggers.•Nutrition affects the production of biosurfactant significantly.
Electroenzymatic C–C Bond Formation from CO2 Cai, Rong; Milton, Ross D; Abdellaoui, Sofiene ...
Journal of the American Chemical Society,
04/2018, Letnik:
140, Številka:
15
Journal Article
Recenzirano
Over the past decade, there has been significant research in electrochemical reduction of CO2, but it has been difficult to develop catalysts capable of C–C bond formation. Here, we report ...bioelectrocatalysis of vanadium nitrogenase from Azotobacter vinelandii, where cobaltocenium derivatives transfer electrons to the catalytic VFe protein, independent of ATP-hydrolysis. In this bioelectrochemical system, CO2 is reduced to ethylene (C2H4) and propene (C3H6), by a single metalloenzyme.
Endophytic bacteria present ubiquitously in all plant parts. Their community structure may vary depending on plant tissue and growth condition. This work mainly focused on exploring the diversity of ...culturable nitrogen-fixing endophytic bacteria in above-ground plant parts of wheat by harvesting it during various growth points (Seed stage, 1st, 2nd, and 3rd month old plants, respectively). Distinct endophytic bacterial colonies were selected on Jensen’s agar plate. Based on the 16S rRNA sequencing, 43 putative nitrogen-fixing endophytic bacteria were identified. Most of the isolates were found unique to the plant growth phase except for
Pseudomonas
sp.,
Bacillus
sp.,
Paenibacillus
sp.,
Microbacterium
sp.,
Exiguobacterium
sp. Further, endophytic bacteria were scrutinized for their plant growth promoting traits. They were found positive for IAA production (100%), P-solubilization (21%), Zn-solubilization (63%), ammonia production (93%), and
nifH
gene (33%). Extracellular enzyme production was found positive for cellulase (98%), pectinase (98%), and protease (100%). Their endophytic colonization ability was assessed using reactive oxygen species (ROS) induction assay, upon their entry inside the host plant.
•Consortium was able to degrade 300ppm phenanthrene within 120h.•Maximum phenanthrene consumption rate was 46mg/h/l.•Consortium ASP could degrade phenanthrene in presence of other petroleum ...hydrocarbons.•Bioaugmentation by consortium showed efficient phenanthrene degradation in microcosm.
A phenanthrene-degrading bacterial consortium (ASP) was developed using sediment from the Alang–Sosiya shipbreaking yard at Gujarat, India. 16S rRNA gene-based molecular analyses revealed that the bacterial consortium consisted of six bacterial strains: Bacillus sp. ASP1, Pseudomonas sp. ASP2, Stenotrophomonas maltophilia strain ASP3, Staphylococcus sp. ASP4, Geobacillus sp. ASP5 and Alcaligenes sp. ASP6. The consortium was able to degrade 300ppm of phenanthrene and 1000ppm of naphthalene within 120h and 48h, respectively. Tween 80 showed a positive effect on phenanthrene degradation. The consortium was able to consume maximum phenanthrene at the rate of 46mg/h/l and degrade phenanthrene in the presence of other petroleum hydrocarbons. A microcosm study was conducted to test the consortium’s bioremediation potential. Phenanthrene degradation increased from 61% to 94% in sediment bioaugmented with the consortium. Simultaneously, bacterial counts and dehydrogenase activities also increased in the bioaugmented sediment. These results suggest that microbial consortium bioaugmentation may be a promising technology for bioremediation.
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