Effect of Lincocin Treatment on the Greening Process in Bean (Phaseolus vulgaris) Leaves

The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –¹⁴CO₂ fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes.     

Lecithotrophic development and metamorphosis in the Indo-West Pacific brittle star Ophiomastix venosa (Echinodermata: Ophiuroidea)

Summary

The larval development of the ophiocomid ophiuroid Ophiomastix venosais described using SEM. The gastrula transforms into a uniformly ciliated early larva which progressively changes into a lecithotrophic late premetamorphic larva with a continuous bilateral ciliated band. This stage is short-lived and equivalent to a highly reduced ophiopluteus. Comparisons between O. venosa and other ophiuroid species whose development has been investigated suggest that, whatever the developmental mode (lecithotrophic or planktotrophic), a pluteus stage always occurs in ophiuroids with planktonic development. Two metamorphic stages were identified, the late metamorphic larva differing from the early one by the closure of the larval mouth. The appearance of the permanent mouth marks the end of the metamorphosis. The postlarva still possesses remnants of larval features. The transformation of the reduced ophiopluteus into a barrel-shaped metamorphic larva with transverse ciliated bands, a vitellaria larva, is followed. The possible occurrence of a unique type of metamorphic larva in non-brooding ophiuroids is discussed. Verification of this, however, needs further SEM investigations on metamorphic larva from species having “regular” planktotrophic development.     

Effect of space flight conditions on properties of hydrocarbon-oxidizing bacteria

Results of experiments on the Mir space station (EO-25 and EO-26) demonstrated that the conditions of orbital flight, primarily the cosmic radiation, was a mutagenic factor affecting both the genotype and phenotype of an oil-oxidizing bacterial strain, Mycobacterium flavescens EX-91. The emerging mutants differed from original culture by the rate of colony growth and the ability to ferment certain carbohydrates or synthesize beta-galactosidase. Changes in the rate of utilization of raw oil and individual hydrocarbon types (constituting model mixtures) suggest that cosmic radiation may serve as a means of obtaining mutant clones of microorganisms with new properties.     

Microbiological degradation of asymmetrical dimethylhydrazine--a toxic component of rocket fuel

A possibility of microbiological cleaning of water and soil polluted with asymmetric dimethylhydrazine (ADMH), a highly toxic rocket fuel ingredient (RFI), was studied. Several isolates (bacteria, yeast, and micromycetes) capable of utilizing ADMH as the only source of nitrogen, carbon, and energy were isolated from RFI-polluted tundra soil. Acceleration of RFI biodegradation was achieved using a biosorbent that involved cells of the degrader strain immobilized on granulated activated carbon. Biological testing in Escherichia coli and cereals (wheat and barley) demonstrated that biodegradation significantly decreased the integral toxicity of solutions containing ADMH, suggesting its utility for microbiological cleaning of polluted territories.     

Development and testing of "Ekosorb" biosorbent based on association of petroleum-oxidizing bacteria for purifying petroleum-polluted soils

A biosorbent containing an association of oil-oxidizing bacteria as a main constituent was developed, in which Lessorb, a product of moss and wood thermal processing, was used as a carrier. Xeroprotectors preserving the cell viability and oil-oxidizing activity in the biosorbent on drying and after long-term storage were selected. The use of this biosorbent for cleaning oil-polluted sod-podzol soils showed a two-threefold cleanup rate acceleration at different pollution levels (8 and 24 l/m2), especially in the presence of a nitrogen-phosphate fertilizer. The biosorbent increased the populations of certain groups of soil microorganisms and the total soil biological activity.