Hydrolysis of acrylonitrile by nitrile-converting bacterial cells immobilized on fibrous carbon adsorbents

Cells of the Pseudomonas fluorescens strain C2 containing nitrilase and Rhodococcus ruber strain gt1 with nitrile hydratase activity have been immobilized by the use of adsorption on fibrous carbon materials. It has been shown that the maximum adsorption value of Rhodococcus cells is higher than that in pseudomonades, reaching 21 mg of dry cells/1 g of the carrier vs. 6 mg, respectively. Cell adsorption, compared to cell suspension, gives a significant rise in nitrilase activity (by 7.4 times, using Ural TM-4 as the carrier) and in the stability of nitrile hydratase activity (5 reaction cycles without loss of activity, using Carbopon-B-active). Immobilized biocatalysts were also obtained by cell growth from Ps. fluorescens strain C2 and Rhodococcus ruber strain gt1 on fibrous carbon adsorbents. Biocatalyst productivity was higher for both strains when the carbonized material Ural TM-4 was used as the carrier.     

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 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.     

Salinicola socius gen. nov., sp. nov., a moderately halophilic bacterium from a naphthalene-utilizing microbial association

A chemoorganotrophic, moderately halophilic bacterium (strain SMB35) has been isolated from a naphthalene-utilizing microbial community obtained from salt mines (Perm region of Russia). Strain SMB35 grows in a wide salinity range, 0.5 to 30% (wt/vol) NaCl. Cells are gram-negative rods motile by means of a single polar flagellum. The predominant fatty acids are 16:1omega7, 16:0, 18:1omega7, and 19 cy. The major lipoquinone is an unsaturated ubiquinone with nine isoprene units (Q-9). The DNA G+C content is 63.0 mol%. The 16S rDNA-based phylogenetic analysis has shown that strain SMB35 formed a separate clade in the cluster of the family Halomonadaceae. The 16S rDNA sequence similarity of the isolate to the members of the family is in the range from 90.6% to 95.1%. The phylogenetic and phenotypic differences from Halomonas elongata (the type species of the genus) and from other members of the family suggest that the isolate represents a novel genus and species, for which the name Salinicola socius gen. nov., sp. nov. is proposed. The type strain is SMB35(T) (=VKM B-2397(T)).     

A New Aerobic Gram-Positive Bacterium with a Unique Ability to Degrade ortho- and para-chlorinated Biphenyls

Strain B51 capable of degrading polychlorinated biphenyls (PCB) was isolated from soil contaminated with wastes from the chemical industry. Based on its morphological and chemotaxonomic characteristics, the strain was identified as a Microbacterium sp. Experiments with washed cells showed that strain B51 is able to degrade ortho- and para-substituted mono-, di-, and trichlorinated biphenyls (MCB, DCB, and TCB, respectively). Unlike the known PCB degraders, Microbacterium sp. B51 is able to oxidize the ortho-chlorinated ring of 2,2-DCB and 2,4-DCB and the para-chlorinated ring of 4.4-DCB. The degradation of 2,4-DCB and 4,4-DCB was associated with the accumulation of 4-chlorobenzoic acid (4-CBA) in the medium in amounts comprising 80–90% of the theoretical yield. The strain was able to utilize 2-MCB, 2,2-DCB, and their intermediate 2-CBA and to oxidize the mono(ortho)-chlorinated ring of 2,4,2-TCB and the di(ortho-para)-chlorinated ring of 2,4,4-TCB. A mixed culture of Microbacterium sp. B51 and the 4-CBA-degrading bacterium Arthrobacter sp. H5 was found to grow well on 1 g/l 2,4-DCB as the sole source of carbon and energy.