Study of the growth and development of chlorella populations in the culture as a whole

Исследовалась цитоморфология двух видов Chlorella в условиях, при которых наблудается в боляшей или меняцей степени циссоциация процессов роста и размножения. В средах различного состава можно было наблуюдатявполне тиничный и воспроизводимый характер (trend) роста и развития кулятуры как целого. Chlorella в основном размножается так, как размножаются клеточные ядра, митохондрии и пластиды. Из них и из их плазмы строятся постепенно сначала безоболочечные и поцвижные проаутоспоры, которые, приобретая оболочку, преврацаются в непоцвижные аутоспоры. Экбалаты и экбластаты —это различные формы ранних фаз развитня проаутоспор. Недостаток магния и серы вызывает быстроепрекрацение способности к размножению и преобладания роста в величниу в сравнении со способностяю водорослей к делению. Чрезмерный рост в величину у Chlorella является не признаком физиологического благополучия, а признаком дегенерации. При зтом Chlorella подвергается вакуолизации и позднее погибает, обычно в результате осмотического растягивания.     

Antibiotics and apochlorosis

Twenty-four out of 38 5-nitrofuran derivatives caused bleaching ofEuglena gracilis similar to that produced by streptomycin, erythromycin and other antibiotics. Derivatives with electron-donor substituents in thep-position of the benzene nucleus attached to position 2 of benzimidazole displayed the greatest bleaching activity. The addition of hydroxylamine to a growingEuglena gracilis culture together with a 5-nitrofuran interfered with the latter's bleaching effect. The mechanism of the effect of 5-nitrofurans on theEuglena gracilis chloroplast system is thus probably identical with the mechanism of the effect of streptomycin and erythromycin. A certain correlation was observed between the bleaching effect and the antibacterial activity of the various 5-nitrofurans tested.     

Methoxy-Substituted Hydroxychalcone Reduces Biofilm Production,Adhesion and Surface Motility of Acinetobacter baumannii by Inhibiting ompA Gene Expression

An increasing lack of available therapeutic options against Acinetobacter baumannii urged researchers to seek alternative ways to fight this extremely resistant nosocomial pathogen. Targeting its virulence appears to be a promising strategy, as it offers considerably reduced selection of resistant mutants. In this study, we tested antibiofilm potential of four synthetic chalcone derivatives against A. baumannii. Compound that showed the greatest activity was selected for further evaluation of its antivirulence properties. Real-time PCR was used to evaluate mRNA expression of biofilm-associated virulence factor genes (ompA, bap, abaI) in treated A. baumannii strains. Also, we examined virulence properties related to the expression of these genes, such as fibronectin- and collagen-mediated adhesion, surface motility, and quorum-sensing activity. The results revealed that the expression of all tested genes is downregulated together with the reduction of adhesion and motility. The conclusion is that 2′-hydroxy-2-methoxychalcone exhibits antivirulence activity against A. baumannii by inhibiting the expression of ompA and bap genes, which is reflected in reduced biofilm formation, adhesion, and surface motility.     

Laboratory evaluation of a new strain CCM 8367 of Isaria fumosorosea (syn. Paecilomyces fumosoroseus) on Spodoptera littoralis (Boisd.)

Laboratory experiments were conducted to assess the efficiency of the new strain CCM 8367 of Isaria fumosorosea on different stages of the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.), including soil treatments with pre-pupal and pupal stages. Treatments of larval instars showed a high susceptibility with 3rd, 5th and last instars to suspension of this fungus with concentration 5?×?10⁷ spores/ml. Larval mortality was over 90%. There were no significant differences (P?=?0.7929, F?=?0.2346) between instar treatments. The commercial fungus, PreFeRal® strain Apopka 97 of I. fumosorosea, which was used in comparison with this new strain caused mortality rates of between 63.33 and 90%. Statistically, differences between the effects of CCM 8367 strain and Apopka 97 were highly significant on the last instar (P?=?0.0064, F?=?6.479) and extremely significant on the 3rd instar (P?<?0.0001, F?=?13.29). No significant differences were recorded between the two strains on the 5th instar (P?=?0.0597, F?=?3.233). Fungal treatments with the late stage insects (end of the last instar or pupal stage) in soil yielded interesting results: the mortality rate on end of final instar larvae was 16.66% when treated with Apopka 97 and 83.33% when treated with CCM 8367. Soil containing pupae of S. littoralis that were inoculated with CCM8367 resulted in a high number of malformed adults, and the mortality rate was 64.52% (32.27% of malformed adults died and 32.25% of pupae fully infected by fungus). Only 3.23% of samples produced morphologically normal adults in this test. The results conclude that the strain of I. fumosorosea CCM 8367 has strong insecticidal effects on S. littoralis and has the potential to be implemented as a novel biocontrol agent.     

Changes of 3,4-dihydroxybenzoic and 4-hydroxybenzoic acids inNicotiana tabacum cell suspension culture

The optimum conditions for cell suspension culture experiments have been characterized by respiration,p-Phenylenediamine oxidase and growth of cell suspension ofNicotiana tabacum for 15 days in stationary culture. Change of 3,4-Dihydroxybenzoic and 4-Hydroxybenzoic acids both present at 10⁻⁴ M in culture medium were studied in short term experiments. An oxidation product of 3,4-Dihydroxybenzoic acid characterized by an absorption maximum at 280 nm was isolated after 1 h of incubation. The 4-Hydroxybenzoic acid did not change when incubated for 4 h under the same conditions.     

Nutritional Evaluation of Genetically Modified Maize Corn Performed on Rats

The aim of this study was to determine the composition and nutritional value of conventional and transgenic, so-called Roundup Ready (RR) maize with an introduced gene of glyphosate resistance. Crude protein, crude fibre, ash, fat, starch, sugar, amino acids, fatty acid and macroelement levels were determined by chemical analysis. In both maize lines a low level of Ca (0.15g.kg m 1 DM) and of the essential amino acids lysine and tryptophan (2.6 and 1.7g.kg^{m 1} DM, respectively) were observed. In the biological experiment carried out on rats the tested maize lines were the only dietary sources of nitrogen, thus, the experimental diets contained 9% CP in dietary dry matter. In the feeding experiment no significant differences in the protein efficiency ratio (PER) were observed between groups receiving conventional or transgenic maize (1.51 and 1.41, respectively). Also almost equal results were obtained in the balance experiments. Both maize lines revealed a high nitrogen digestibility (84.9 and 84.5%, respectively) and the net protein utilization amounted to 63.5 and 63.2%, respectively. From these results can be concluded that regarding nutrient composition and utilisation, genetically modified (RR) maize is equivalent to isogenic maize.     

Transport systems for acyclic polyols and monosaccharides inTorulopsis candida

The yeastTorulopsis candida NCYC 576 was found to transport acyclic polyols (D-arabinitol,L-arabinitol, ribitol, xylitol,D-mannitol,D-glucitol and erythritol) and monosaccharides (D-galactose,L-sorboseD-xylose) by an active process, reaching high intracellular concentrations, making use of four different carrier systems: (1) high-affinity for polyols, (2) high-affinity for monosaccharides, (3) lowaffinity for both polyols and monosaccharides, and (4) specific high-affinity for erythritol andD-ribose.     

Differential Cellular Effects of Electroporation and Electrochemotherapy in Monolayers of Human Microvascular Endothelial Cells

In vivo electroporation of tumours shows disruption of blood flow and creates a vascular effect with an initial rapid and transient vasoconstriction phase and a much longer lasting phase with changed microvascular endothelium. These changes are not well understood but are presumed to involve the cytoskeleton. The paper presents for the first time differential in vitro effects describing cytoskeleton changes and monolayer integrity changes by both electroporation and electrochemotherapy of monolayers of human microvascular endothelial cells (HMEC-1). After the application of electric field pulses, the morphology of cells, and both the F-actin and Beta-tubulin cytoskeleton proteins were affected. During both electroporation and electrochemotherapy, the initial phase of cellular damage was noticed at 10 min as swollen cells and honeycomb-like actin bundles. The electroporation-induced cellular effects, observed from electric pulses >150 V, were voltage-dependent and within 24 hrs partly recoverable. The electrochemotherapy-induced cellular effects developed at 2 hrs in spindle-like cells, and more densely packed F-actin and Beta-tubulin were observed, which were dependent on the amount of bleomycin and the voltages applied (>50 V). In addition, for electrochemotherapy with electric pulses >150 V cellular changes were not recoverable within 24 hrs. The effects on monolayer integrity were reflected in the enhanced monolayer permeability, with the electrochemotherapy showing an earlier onset and synergy. We conclude that electrochemotherapy as compared to electroporation leads within 24 hrs to a quicker and more pronounced monolayer integrity damage and endothelial cell death, which together provide further insight into the cellular changes of the vascular disruption of electrochemotherapy.     

Nonlinear dynamics of the blood flow studied by Lyapunov exponents

In order to gain an insight into the dynamics of the cardiovascular system throughout which the blood circulates, the signals measured from peripheral blood flow in humans were analyzed by calculating the Lyapunov exponents. Over a wide range of algorithm parameters, paired values of both the global and the local Lyapunov exponents were obtained, and at least one exponent equaled zero within the calculation error. This may be an indication of the deterministic nature and finite number of degrees of freedom of the cardiovascular system governing the blood-flow dynamics on a time scale of minutes. A difference was observed in the Lyapunov dimension of controls and athletes.