Green synthesis of different nanoparticles using the plants aqueous extracts has several advantages over other methods due to the environmentally favorable nature of plants. moreover, such approach is also cost effective. This work describes the biosynthesis of silver nanoparticles (Ag-NPs) with the use of the aqueous extract of dry pericarps of hot chili peppers and cv. Carolina Reaper) with different levels of pungency and their antibacterial effect on the antibiotic resistant Pseudomonas aeruginosa. Phytochemical screening of pericarp tissues showed great distinction in contents of phenolic compounds and capsaicinoids as potential reducing agents wich correlated with total antiradical activity as analyzed by reduction of DPPH radicals. The biosynthesized Ag-NPs were characterized by UV-vis spectrophotometry and scanning electron microscopy (SEM). The average size of the nanoparticles in both samples was less than 25 nm. Іnitial concentration of both samples of Ag-NPs inhibited P. aeruginosa growth with equal efficiency.
скринінг продуцентів пептидаз, а також a-L-рамнозидаз серед актинобактерій та бацил. Методи. Були використані біохімічні методи визначення a-L-рамнозидазної, еластазної, казеїнолітичної, фібринолітичної та колагеназної активностей. Результати. Внаслідок скринінгу, проведеного серед 31 штаму ак тинобактерій та 24 штамів бацил, не виявлено жодного штаму актинобактерій, здатного синтезувати ензим з еластазною активністю, але деякі актинобактерії виявилися активними продуцентами колагеназ. Що стосується бацил, то еластолітична активність була виявлена тільки в п ' яти досліджених штамах, але її рівень не представляє інтересу до подальших досліджень, у той час як фібринолітична активність двох штамів Bacillus subtilis 121 і 108 була досить високою (0,100 од/ мг і 0,092 од/мг білка відповідно). Висновки. Найбільш ефективними продуцентами колагенази і a-L-рамнозидази є штам актинобактерій 6/5, виділений з ризосфери кропиви, а пептидази з фібринолітичною активністю-B. subtilis 121 і 108. Ці шта ми можна вважати перспективними для подальших досліджень.
Virus diversity in Antarctic biotopes remains understudied. Here, we describe bacteriophages isolated from terrestrial environments, provide data on their natural bacterial hosts and study phage-host systems. Six bacterial isolates (FCKU 539, FCKU 533, FCKU 534, FCKU 538, FCKU 542 and FCKU 540) were recovered and characterized. Isolated bacteria belonged to Pseudomonas genus (Pseudomonas sp., Pseudomonas fluorescens, Pseudomonas putida) with optimal cultivation temperatures of 16–28°C. These bacteria and previously described Bacillus subtilis FCKU 537 were used for analysing virus-host interactions. Six lytic phages were isolated and named P. fluorescens Antarctic virus 1 (PFAV1), P. fluorescens Antarctic virus 2 (PFAV2), P. fluorescens Antarctic virus 3 (PFAV3), P. putida Antarctic virus 4 (PPAV4), Pseudomonas sp. Antarctic virus 5 (PSAV5) and B. subtilis Antarctic virus 6 (BSAV6) in relation to their natural hosts. According to electron microscopy data, these phages belonged to Caudovirales order. Cross-inoculation demonstrated high specificity of all Antarctic phages, which infected only their initial hosts at moderate temperatures. PFAV2 and PFAV3 phages also infected laboratory Pseudomonas savastanoi and P. fluorescens isolates. This paper adds new data on the occurrence and diversity of viruses and their respective bacterial hosts in soil biotopes of Antarctica.
Deep insight into compositional and functional features of endophytic bacterial communities residing in wheat grains opens the way to the use of their plant growth promoting and biocontrol abilities in agricultural biotechnology. The aim of this work was to compare grain-residing endophytes from winter wheat varieties with different sensitivity to Pseudomonas syringae pv. atrofaciens (McCulloch) and to examine their plant-beneficial traits and antagonistic effects. Grain-residing bacteria were isolated from surface-sterilized grains of three wheat varieties sown in Ukraine following a culture-dependent protocol, and were screened for their plant growth promotion (PGP) and antagonistic properties. Bacterial morphotypes were represented by gram-negative rods, endospore-forming bacilli and gram-positive cocci. Different resistance to phytopathogenic pseudomonads was associated with distinctive quantitative and functional features of grain-residing endophytic communities. High resistance to P. syringae was coupled with the prevalence of gram-negative rods in the endophytic community, the highest proportion of endophytic bacteria possessing three PGP activities (phosphate solubilization, nitrogen fixation and production of indolic compounds) simultaneously, and with the most potent antagonistic activity of grain-residing endospore-forming bacilli. In total, five grain-residing isolates, which were obtained from three wheat varieties (two isolates from varieties with medium and high resistance and one – from a low-resistant variety), demonstrated ability to restrain P. syringae pv. atrofaciens (McCulloch) growth. Two isolates (P6 and P10) which were obtained from the high-resistant wheat variety Podolyanka and were assigned to Paenibacillus and Brevibacillus genera according to their biochemical profiling and MS-DS identification, showed the most potent antagonistic effects as indicated by maximum inhibition zone in agar well diffusion assay. These results shed light on the association of the features of grain-residing endophytic bacteria with wheat resistance to phytopathogenic pseudomonads. Isolates from the high-resistant wheat variety can be recommended for grain dressing as plant growth promoting and biocontrol agents for P. syringae pv. atrofaciens (McCulloch).
Physiological, biochemical, cyto-morphological properties of initial strain Candida albicans ATCC 10331, Saccharomyces sp. КНУ 1 and their variants, which were cultivated in medium Saburo with anionic surfactant (SAS) sodium dodecyl sulfate (SDS) have been compared. It was shown that the effect of SDS was accompanied by disappearance of possibility to assimilate a number of substrates, but did not affect antibiotics sensitivity. They changed its morphology after 1 passage, diminution quantity of volutin, appearance of fat inclusion. Morphology of cells partially restored after 4-th passage.
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