cultivation conditions
Recently Published Documents

The main focus of the study was to determine the content of phenolic acids, flavonoids, and organic acids in the flowers of Tagetes patula ‘Petite Gold’ and ‘Petite Orange’. The growth of the plants was assessed depending on the cultivation conditions. The above plants were illuminated with white light, whereas the ‘Petite Gold’ ones with white light enhanced with blue or red light. Both cultivars grew in a two-level-mineral compounds organic substrate. The research showed that the French marigold flowers were rich in phenolic compounds and organic acids. The ‘Petite Gold’ flowers had more bioactive compounds compared with the ‘Petite Orange’ flowers. Three flavonoids, 10 phenolic acids and seven organic acids were found in the ‘Petite Gold’ flowers. The artificial lighting used during the cultivation of the plants showed diversified influence on the content of organic compounds in their flowers. The measurements of the plants’ morphological traits and the number of inflorescences showed that illumination with red light resulted in a better effect. Large plants with numerous inflorescences grew in the substrate with a lower content of nutrients.

In previous publications, it was hypothesized that Micrarchaeota cells are covered by two individual membrane systems. This study proves that at least the recently cultivated “ Candidatus Micrarchaeum harzensis A_DKE” possesses an S-layer covering its cytoplasmic membrane. The potential S-layer protein was found to be among the proteins with the highest abundance in “ Ca. Micrarchaeum harzensis A_DKE” and in silico characterisation of its primary structure indicated homologies to other known S-layer proteins. Homologues of this protein were found in other Micrarchaeota genomes, which raises the question of whether the ability to form an S-layer is a common trait within this phylum. The S-layer protein seems to be glycosylated and the Micrarchaeon expresses genes for N-glycosylation under cultivation conditions, despite not being able to synthesize carbohydrates. Electron micrographs of freeze-etched samples of a previously described co-culture, containing Micrarchaeum A_DKE and a Thermoplasmatales member as its host organism, verified the hypothesis of an S-layer on the surface of “ Ca. Micrarchaeum harzensis A_DKE”. Both organisms are clearly distinguishable by cell size, shape and surface structure. Importance Our knowledge about the DPANN superphylum, which comprises several archaeal phyla with limited metabolic capacities, is mostly based on genomic data derived from cultivation-independent approaches. This study examined the surface structure of a recently cultivated member “ Candidatus Micrarchaeum harzensis A_DKE”, an archaeal symbiont dependent on an interaction with a host organism for growth. The interaction requires direct cell contact between interaction partners, a mechanism which is also described for other DPANN archaea. Investigating the surface structure of “ Ca. Micrarchaeum harzensis A_DKE” is an important step towards understanding the interaction between Micrarchaeota and their host organisms and living with limited metabolic capabilities, a trait shared by several DPANN archaea.

This study aimed to evaluate the effect of cultivation conditions in the context of light on the retention of selected vitamins, minerals and polyphenols in the stem and cap of the oyster mushroom (Pleurotus ostreatus L.). Additionally, the effect of the retention of bioactive components on the antioxidant activity of mushroom extracts was evaluated, taking into account the morphological part. Oyster mushrooms grown in the light of 200 lux had higher riboflavin content compared to mushrooms exposed to the light of lower intensity. The thiamine content of the mushrooms dropped with decreasing light intensity during cultivation. The content of biologically active compounds was found to be equal in the stem and the cap. In the case of riboflavin, it was shown that its contents in cap fractions, irrespective of the cultivation method, was statistically significantly higher than in stems. The mineral composition of caps and stems differed from each other. No differences in Zn and Cu content between the morphological parts of the mushroom studied were found. However, it was shown that the stems, regardless of the type of light, contained less iron, magnesium and sodium. Thus, it was observed that limited light exposure caused an increase in the content of total polyphenolic compounds, which did not correlate with antioxidant activity. There was no effect of the light on the antioxidant activity of mushrooms. It was also shown that stem extracts had higher antioxidant activity compared to the extracts obtained from the caps. This findings point to the possibility and potentail of use both fraction of mushrooms in the new food products development.

Peas, as a valuable nutritious and cultivated plant (Myers et al., 2010), have recently received special attention for the improvement of new varieties (Kreplak et al., 2019). They are increasingly adapted to any kind of environmental conditions. Thus, we want an increased production of grains, contents in active principles as high as possible (Pownall et al., 2010), but also to increase its proportion in the structure of crops on a farm. The Alvesta variety, studied for its specific morphological characters, is one of the newest creations. Even in the slightly drier conditions of the last period (two years), this variety formed plants with heights of 42-45 cm, with a total plant weight of 7.5 g. 10 knots were formed on a pea stem (at one node the floral and fruit raceme are caught and formed). Each plant formed 4 pods, weighing 6 g and 16 berries weighing 4.5-6 g. The bean had a diameter of 7 mm and the absolute weight of the berries was 215 g. Among these morphological characters were obtained significantly positive correlations in most cases. Insignificant situations were between the absolute mass of the berries with the size of the plant, with the number of nodes, with the total number of pods and with the number of berries on a plant. Only one insignificant negative correlation was observed between the number of nodes on the stem and the diameter of the grains. Regarding the variability of the determined characters, slightly higher values were found, mainly due to the existence of the dry bottom. And yet the Alvesta variety, with improved morphological characters proved to be a good adaptability to zonal cultivation conditions.

This study investigated the effect of various cultivation conditions (sucrose/phosphate concentrations, aeration level) on alginate biosynthesis using the bacterial producing strain Azotobacter vinelandii 12 by the full factorial design (FFD) method and physicochemical properties (e.g., rheological properties) of the produced bacterial alginate. We demonstrated experimentally the applicability of bacterial alginate for tissue engineering (the cytotoxicity testing using mesenchymal stem cells (MSCs)). The isolated synthesis of high molecular weight (Mw) capsular alginate with a high level of acetylation (25%) was achieved by FFD method under a low sucrose concentration, an increased phosphate concentration, and a high aeration level. Testing the viscoelastic properties and cytotoxicity showed that bacterial alginate with a maximal Mw (574 kDa) formed the densest hydrogels (which demonstrated relatively low cytotoxicity for MSCs in contrast to bacterial alginate with low Mw). The obtained data have shown promising prospects in controlled biosynthesis of bacterial alginate with different physicochemical characteristics for various biomedical applications including tissue engineering.

Every year the volume of production of poultry products all over the world is growing steadily. This contributes to a constant increase in the amount of by-products of poultry processing in the form of down and feather waste, which are dangerous for the environment due to the hard-to-degrade keratin protein and a large number of microbial pathogens. Therefore, the use of environmentally friendly methods for the destruction of keratin substrates due to keratinases of microorganisms is an urgent area of research. The aim of this work was to select the optimal cultivation conditions for the Bacillus megaterium strain UCM B-5710 to increase the activity of the keratinase synthesized by it. Methods. The culture was grown at 28°C, 201 rpm for 7 days on a basic nutrient medium containing defatted chicken feathers as the only source of carbon and nitrogen. The selection of optimal cultivation conditions was carried out according to the following parameters: temperature (21°C, 28°C, 42°C), stirring speed (201 rpm, 212 rpm), amount of inoculum (5%, 10%, 15% , 20%, 25%), the initial pH value of the nutrient medium (4.0–11.0), concentration of keratin-containing substrate (0.1%, 0.2%, 0.5%, 1.0%, 1.5%, 2.0%), additional carbon source (glucose, galactose, lactose, maltose, sucrose, mannitol, potato and corn starch, soluble starch, soybean meal) and nitrogen (NH4Cl, NH4NO3, (NH4)2SO4, NaNO3, urea, peptone, tryptone, yeast extract and soybean meal) at a concentration of 1%. Keratinase activity was assessed by the UV absorption at 280 nm of the hydrolysis products of keratin-containing raw materials. Protein was determined by the Lowry method. Results. The dynamics of the enzyme synthesis showed that the culture of B. megaterium UCM B-5710 exhibited the highest keratinase activity on the 3rd day, and complete splitting of feathers was observed on the 4–5th days. The selection of the concentration of the keratin-containing substrate showed that 0.5% is the optimal concentration. The study of the influence of the initial pH value of the nutrient medium indicates that the culture grew well at pH 6.0–7.0 and pH 9.0–11.0, but at pH 8.0 its growth was very weak. The culture exhibited the maximum keratinase activity at pH 10.0. In addition, at this pH value, complete splitting of feathers was visually observed. The influence of such a key factor as temperature on the growth and synthesis of the enzyme by B. megaterium UCM B-5710 culture demonstrated complete splitting of feathers already on the 2nd day of cultivation at 42°C, at 21°C the culture split feathers very poorly. The introduction of the inoculum into the composition of the nutrient medium in an amount of 15% of the volume of the medium and the mixing intensity of 212 rpm turned out to be optimal. Besides, it was shown that the introduction of an additional source of carbon or nitrogen had an ambiguous effect on the level of keratinase activity of B. megaterium UCM B-5710. Complete inhibition of enzyme synthesis was observed when ammonium sulfate was added to the nutrient medium, and partial inhibition was observed in the case of glucose, lactose, and maltose. Potato, corn, and soluble starch stimulated keratinase synthesis. The majority of inorganic nitrogen sources (ammonium chloride and nitrate) did not affect the synthesis of B. megaterium UCM B-5710 keratinase, while organic sources (urea, peptone, tryptone, yeast extract) increased the level of keratinase activity by 20–50%. However, the most effective result was obtained using soybean meal, the addition of which to the nutrient medium increased the keratinase activity by 2.5 times. Conclusions. As a result of the studies, the optimal conditions for cultivation of the B. megaterium UCM B-5710 strain were selected: the optimum temperature for the growth and development of the culture is 42°C, the initial pH value is 10.0, the stirring speed is 212 rpm and the amount of inoculum introduced is 15%, an additional source of carbon and nitrogen in the form of soybean meal at a concentration of 0.5%. This made it possible to increase the activity of keratinase by 4 times.

In agricultural production, it is important not only to achieve a high productivity, but also to ensure its stability. To obtain high and stable yields, it is necessary to have information on the adaptability of crops varieties and hybrids to a specific cultivation zone. The article analyzes the results of the field experiment on the variety testing of sweet pepper. To assess the variety for adaptability to natural conditions and cultivation technology in the Astrakhan region, such parameters as plasticity and stability of the variety were used. To characterize the ecological plasticity, the regression coefficient bi was determined, which characterizes response of the cultivar to changes in cultivation conditions. To characterize the parameter of stability, the standard deviation from the regression line 2d. was calculated. All calculations were carried out according to S.A. Eberhart, W.A. Russell as presented by V.Z. Pakudin.