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S. Kebbouche-Gana M. L. Gana S. Khemili F. Fazouane-Naimi N. A. Bouanane M. Penninckx H. Hacene 《Journal of industrial microbiology & biotechnology》2009,36(5):727-738
Halotolerant microorganisms able to live in saline environments offer a multitude of actual or potential applications in various
fields of biotechnology. This is why some strains of Halobacteria from an Algerian culture collection were screened for biosurfactant
production in a standard medium using the qualitative drop-collapse test and emulsification activity assay. Five of the Halobacteria
strains reduced the growth medium surface tension below 40 mN m−1, and two of them exhibited high emulsion-stabilizing capacity. Diesel oil-in-water emulsions were stabilized over a broad
range of conditions, from pH 2 to 11, with up to 35% sodium chloride or up to 25% ethanol in the aqueous phase. Emulsions
were stable to three cycles of freezing and thawing. The components of the biosurfactant were determined; it contained sugar,
protein and lipid. The two Halobacteria strains with enhanced biosurfactant producers, designated strain A21 and strain D21,
were selected to identify by phenotypic, biochemical characteristics and by partial 16S rRNA gene sequencing. The strains
have Mg2+, and salt growth requirements are always above 15% (w/v) salts with an optimal concentration of 15–25%. Analyses of partial
16S rRNA gene sequences of the two strains suggested that they were halophiles belonging to genera of the family Halobacteriaceae,
Halovivax (strain A21) and Haloarcula (strain D21). To our knowledge, this is the first report of biosurfactant production at such a high salt concentration. 相似文献
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Sahouli Salima Abdeddaim Katia K. Werbrouck Stefaan P. O. 《In vitro cellular & developmental biology. Plant》2022,58(4):664-670
In Vitro Cellular & Developmental Biology - Plant - Oleasters are olive genotypes that range from wild to feral. They are tolerant to biotic and abiotic stresses and are easily propagated. This... 相似文献
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Alexander V. Lebedinsky Andrey V. Mardanov Ilya V. Kublanov Vadim M. Gumerov Alexey V. Beletsky Anna A. Perevalova Salima Kh. Bidzhieva Elizaveta A. Bonch-Osmolovskaya Konstantin G. Skryabin Nikolai V. Ravin 《Extremophiles : life under extreme conditions》2014,18(2):295-309
The complete genome of the obligately anaerobic crenarchaeote Fervidicoccus fontis Kam940T, a terrestrial hot spring inhabitant with a growth optimum of 65–70 °C, has been sequenced and analyzed. The small 1.3-Mb genome encodes several extracellular proteases and no other extracellular hydrolases. No complete pathways of carbohydrate catabolism were found. Genes coding for enzymes necessary for amino acid transamination and further oxidative decarboxylation are present. The genome encodes no mechanisms of acyl-CoA and acetyl-CoA oxidation. Two [NiFe]-hydrogenases are encoded: a membrane-bound energy-converting hydrogenase and a cytoplasmic one. The ATP-synthase is H+-dependent as inferred from the amino acid sequence of the membrane rotor subunit. On the whole, genome analysis shows F. fontis to be a peptidolytic heterotroph with a restricted biosynthetic potential, which is in accordance with its phenotypic properties. The analysis of phylogenetic markers and of the distribution of best blastp hits of F. fontis proteins in the available genomes of Crenarchaeota supports distinct phylogenetic position of the order Fervidicoccales as a separate lineage adjoining the heterogeneous order Desulfurococcales. In addition, certain F. fontis genomic features correlate with its adaptation to temperatures of 60–80 °C, which are lower than temperatures preferred by Desulfurococcales. 相似文献
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Sanchita Bhattacharya Salima Virani Mashenka Zavro Gerhard J. Haas 《Economic botany》2003,57(1):118-125
We report the inhibition of the causative agents of dental caries, Streptococcus mutans and other oral streptococci, by the
antimicrobially active ingredients of the hop plant (Humulus lupulus L.). The hop constituents studied were purified beta acid, xanthohumol, isoalpha acid and tetra iso-alpha acid. Cruder hop
extracts were also investigated. The antimicrobial activity of these hop constituents was tested against four strainsof Streptococcus mutans as well as one strain each ofStreptococcus sanguis andStreptococcus salivarius and compared to antimicrobial essential oils used in mouthwashes in two independent assay systems. We found that all tested
hop constituents inhibited the Streptococci. The minimum inhibitory concentration at pH 7.5 ranged from 2 to 50 μg/ml depending
on the microorganism and hop phytochemical tested. Contrary to a previous report, there was no activity enhancement by ascorbic
acid over and above the enhancement due to pH lowering. Thére was no resistance development to beta acid after 10 passages
in a subinhibitory concentration of this acid. Antimicrobial activity of hop constituents was found to be greater than other
plant products such as thymol, nerol, cinnamon oil, oil of clove, menthol and eucalyptol. The possibilities of using hop constituents
in mouthwashes are discussed. 相似文献
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Background
Fatigue is one of many unintended consequences of shift work in the nursing profession. Natural health products (NHPs) for fatigue are becoming an increasingly popular topic of clinical study; one such NHP is Rhodiola rosea. A well-designed, rigorously conducted randomized controlled trial is required before therapeutic claims for this product can be made.Objective
To compare the efficacy of R. rosea with placebo for reducing fatigue in nursing students on shift work.Design
A parallel-group randomized, double-blinded, placebo-controlled trial of 18–55 year old students from the Faculty of Nursing from the University of Alberta, participating in clinical rotations between January 2011 and September 2011.Interventions
Participants were randomized to take 364 mg of either R. rosea or identical placebo at the start of their wakeful period and up to one additional capsule within the following four hours on a daily basis over a 42-day period.Outcomes
The primary outcome was reduction in fatigue over the 42-day trial period measured using the Vitality-subscale of the RAND-36, cross-validated by the visual analogue scale for fatigue (VAS-F). Secondary outcomes included health-related quality of life, individualized outcomes assessment, and adverse events.Results
A total of 48 participants were randomized to R. rosea (n = 24) or placebo (n = 24). The mean change in scores on the Vitality-subscale was significantly different between the study groups at day 42 in favor of placebo (−17.3 (95% CI −30.6, −3.9), p = 0.011), The mean change in scores on the VAS-F was also significantly difference between study groups at day 42 in favour of placebo (1.9 (95% CI 0.4, 3.5), p = 0.015). Total number of adverse events did not differ between R. rosea and placebo groups.Conclusion
This study indicates that among nursing students on shift work, a 42-day course of R. Rosea compared with placebo worsened fatigue; however, the results should be interpreted with caution.Trial Registration
Clinicaltrials.gov NCT01278992相似文献8.
To determine the effects of vermicompost leachate (VCL) on resistance to salt stress in plants, young tomato seedlings (Solanum lycopersicum, cv. Ailsa Craig) were exposed to salinity (150 mM NaCl addition to nutrient solution) for 7 days after or during 6 mL L??1 VCL application. Salt stress significantly decreased leaf fresh and dry weights, reduced leaf water content, significantly increased root and leaf Na+ concentrations, and decreased K+ concentrations. Salt stress decreased stomatal conductance (gs), net photosynthesis (A), instantaneous transpiration (E), maximal efficiency of PSII photochemistry in the dark-adapted state (Fv/Fm), photochemical quenching (qP), and actual PSII photochemical efficiency (ΦPSII). VCL applied during salt stress increased leaf fresh weight and gs, but did not reduce leaf osmotic potential, despite increased proline content in salt-treated plants. VCL reduced Na+ concentrations in leaves (by 21.4%), but increased them in roots (by 16.9%). VCL pre-treatment followed by salt stress was more efficient than VCL concomitant to salt stress, since VCL pre-treatment provided the greatest osmotic adjustment recorded, with maintenance of net photosynthesis and K+/Na+ ratios following salt stress. VCL pre-treatment also led to the highest proline content in leaves (50 µmol g??1 FW) and the highest sugar content in roots (9.2 µmol g??1 FW). Fluorescence-related parameters confirmed that VCL pre-treatment of salt-stressed plants showed higher PSII stability and efficiency compared to plants under concomitant VCL and salt stress. Therefore, VCL represents an efficient protective agent for improvement of salt-stress resistance in tomato. 相似文献
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Nima Taha Jing Zhang Reza Rafie Rupesh Ranjan Salima Qamruddin Tasneem Z Naqvi 《Cardiovascular ultrasound》2011,9(1):1-12