ABSTRACT
This review presents the main directions and experimental data to search among the different species of yeast--active producers of lipids and the ways to lipidogenesis process optimization in the most promising stains. It was shown that enzymatic processes course can be directed with maintaining the necessary cultivation conditions. The influence on the growth, development and biochemical activity of microbial medium composition, temperature, aeration and oxidation-reduction conditions was considered. These factors changing have affected the microorganisms biosynthetic activity, lipidogenic yeasts activity and synthesized lipids composition. Lipidogenic yeasts ability and relatively rapid ability on changing the amount and composition of lipids by the direct cultivation leads to the conclusion that lipids obtained by microbial synthesis can be a source of commercial raw materials for biofuel.
Subject(s)
Biofuels , Candida/metabolism , Lipids/biosynthesis , Pichia/metabolism , Rhodotorula/metabolism , Candida/chemistry , Culture Media , Lipid Metabolism , Oxidation-Reduction , Pichia/chemistry , Rhodotorula/chemistry , TemperatureABSTRACT
In search of effective means of harmful fauna control, which could be practically safe for man and domestic animals, the authors tested efoxen-II, a juvenile insect hormone analogue (JHA) synthesized at the Institute of Chemistry, the Estonian Acad. of Sci. (Tallinn). Experiments were performed with Xenopsylla skrjabini Ioff., 1903 fleas under laboratory conditions. The doses of the drug tested were the following: 0.25.10(-2); 0.25 X 10(-3); 0.25.10(-4); 0.25.10(-5) ml/g per 1 g the substrate consisting of sand and dry bovine blood (for larvae feeding). Juvenile fleas' contact with the drug altered the normal metamorphosis process, thus killing the majority of fleas. The drug given in a dose of 0.25.10(-2) ml/g killed 100% of larvae by the 8th day of the experiment. The drug added to the substrate at 0.25.10(-3) ml/g prolonged metamorphosis stages, some larvae were killed during the moult, others (0.3%) formed pupae and died inside them. Larvae contact with the drug at 0.25.10(-4) and 0.25.10(-5) ml/g resulted in partial death. The insects survived (36.6 and 46.6%, respectively) completed metamorphosis by imago hatching. Thus, the drug tested by the authors proved to be considerably effective and may be recommended for in situ testing.
Subject(s)
Juvenile Hormones , Siphonaptera , Animals , Disease Vectors , Dose-Response Relationship, Drug , Gerbillinae/parasitology , Larva , Plague/transmission , Time FactorsABSTRACT
The authors tested the effect of the analogue of juvenile hormone (AJH), ether-farnesol, synthesized at the Institute of Chemistry of the Academy of Sciences of ESSR (the city of Tallin), on immature stages of X. cheopis. When testing the following doses of AJH (0.0025, 0.00025, 0.000025, 0.0000025 ml per lg of substrate, consisting of sand and dry bull blood, for feeding larvae) it was established that the dose of 0.0025 ml/g causes 100% mortality of insects on the 2nd day of the experiment. 10 fold decrease in ether-farnesol dose causes the mortality of the majority of larvae. Only 13.6% of them formed cocoons, which failed to produce mature individuals. A repeated 10 and 100 fold decrease of AJH caused mortality in 50.0 and 46.7% of insects, respectively. The effect of the preparation stipulated the disturbance of the normal course of metamorphosis (changes in the data of phases replacement and the mortality of insects during their moulting).
