Magnetic field-induced increase of the yield of (bacterio)chlorophyll emission of some photosynthetic bacteria and of Chlorella vulgaris.

In photosynthetic bacteria, in which the iron-ubiquinone complex X is prereduced, a magnetic field induces an increase of the emmission yield, which is correlated with the decrease in reaction center triplet yield reported previously (Hoff, A.J., Rademaker, H., van Grondelle, R. and Duysens, L.N.M. (1977) Biochim. Biophys. Acta 460, 547--554). Our results support the hypothesis that under these conditions charge recombination of the oxidized primary donor and the reduced primary acceptor predominantly generates the excited singlet state of the reaction center bacteriochlorophyll. In Chlorella vulgaris and spinach chloroplasts, at 120 K, the magnetic field has an effect similar to that found in bacteria, which suggests that an intermediary electron acceptor between P-680 and Q is present in Photosystem II also.

[Analysis of ribosomes by polyacrylamide gel electrophoresis (author's transl)]. / Analyse de ribosomes par électrophorèse en gel de polyacrylamide

Ribosomal polymers, monomers and subunits from several eukaryotes and prokaryotes were isolated and analyzed by polyacrylamide gel electrophoresis. Extraction of RNA from ribosomal particles after their migration in a polyacrylamide gel, analyses by sedimentation in sucrose gradients and observations in the electron microscope were carried out in parallel. Attention was directed to the reproducibility, the precision and the limitations of the electrophoresis technique.

Content of fatty acids of Chlorella kessleri in a deep tank fermentation.

Chlorella kessleri cultivated in a deep tank contained 4.8% of non-polar lipid; 51% of this fraction represents saturated fatty acids, 7% unsaturated fatty acids. Our investigation of the fatty acids profile demonstrated even- and odd-numbered saturated and unsaturated fatty acids ranging from C12 to C20. Unlike in other Chlorella species, stearic acid was the dominant fatty acid found. Also shown was an elevated C16:0 fatty acid content and a reduced level of unsaturated fatty acids.

Hydrocarbons in green and blue-green algae.

Liquid column chromatography and thin-layer chromatography were used to determine the total content of hydrocarbons and gas chromatography was used to evaluate composition of hydrocarbons in green algae (Chlorella kessleri, C. vulgaris, Chlorella sp., Scenedesmus acutus, S. acuminatus, S. obliquus) and the blue-green alga (Spirulina platensis) cultivated under autotrophic or heterotrophic conditions. In C. kessleri cultivated under heterotrophic conditions the content of hydrocarbons was found to be about 10(-2)% (per dry mass), whereas under autotrophic conditions it was about 10(-3)% (per dry mass). The highest content of hydrocarbons was detected in species of the genus Scenedesmus cultivated autotrophically (10(-1)%). Heptadecane and hexacosane were found as major alkanes, 1-heptadecene was detected among alkenes.

[Nuclear RNP containing pre-mRNA. 16. Cross-linked informofers]. / Iadernye RNP, Soderszhashcie pre-mRNK. XVI. "Zashitye" informofery.

The proteins of 30S RNP particles containing pre-mRNA (hnRNA) were cross-linked with bifunctional reagents (dimethylsuberimidate and dimethyl-3,3'dithiobispropionimi-date). Further treatment with 1 or 2 M NaCl dissociates all RNA from protein. However, a significant part of protein particles--informofers, being cross-linked survived high salt treatment. Their sedimentation coefficients were close to those of original particles. No RNA could be detected in the informofers even after labeling the cells with a precursor for a long period of time. Sodium dodecylsulfate or urea dissociated cross-linked informofers into oligomeric polypeptides. They could be dissociated by beta-mercaptoethanol treatment if a reversible cross-linking reagent has been used. The resulting polypeptides were represented by informatin. RNP particles (30S RNP or polyparticles) were reconstituted upon mixing or cross-linked informofers with pre-mRNA and removal of 2 M NaCl. The reconstituted particles were indistinguishable from the original ones by several tests.

Immunological identification and quantification of light harvesting chlorophyll a/b protein of Chlorella protothecoides.

The alteration of photosynthetic membrane proteins in relation to the disappearance of pigments during the heterotrophic growth of Chlorella protothecoides was investigated. Chlorophylls and certain polypeptides associated with the LHC II disappeared after 50 hr of heterotrophic growth but the 24 kDa apoprotein constituting LHC II was not affected. Immunological analysis indicated that the chlorophylls and the light harvesting complex proteins of the thylakoid membranes are not tightly coupled and the latter is retained in its native form irrespective of the presence or absence of the former. The circumstantial evidence that the other photosynthetic membrane polypeptides are degraded along with the pigments due to increased proteolytic activity in the rapidly dividing heterotrophic cells indicate that chlorophyll synthesis is not a pre-requisite for the synthesis of the LHC II apoprotein.

[Spectrophotometry of individual Chlorella cells]. / Spektrofotometriia otdel'nykh kletok khlorelly

A research of optical properties of individual microalgae Chlorella vulgaris cells was performed under various conditions of cultivation. On the basis of cell absorption spectra measurements in the visible spectrum region chlorophyll "a" absorption maxima are estimated to fall within the intervals of 669-675 nm for the red region of the spectrum and 429--436 nm for the blue one. Concentration of chlorophylls in the cells of the diameter from 2,8 up to 3,3 micrometers was found to increase considerably for algae grown both in continuous denisty static and periodical regimes. Integral optical density of individual Chlorella cells in the range of 400-750 nm grows with cell diameter increase. This increase appears to be most intensive in the cells grown in density static regime. A correlation was also established between algae cell dimensions and the general maxima position (correlation coefficient has a positive sign and absolute value near unit). With cell diameter growth the absorption maxima shift to the region of long waves.

[Extraction of deuterated compounds from Chlorella sp. K. grown in D20]. / Poluchenie deiterirovannykh soedinenii iz Chlorella sp. K., vyrashchennoi v D20

A comparison of the three known methods made it possible to work out methods of complex extraction of deutero amino acids, deutero sugars and deutero vitamins from algae Chlorella sp. K., grown autotrophically in heavy water. An analysis of the isotopic composition of deutero amino acids by PMR indicates that treatment with HCl introduces 1H into side chains of some amino acids by chemical exchange (C2, 6H of tyrosine, C2H of histidine, rho-H of phenylalanin, beta-CH2-aspartate and gamma-CH2-glutamate. These exchanges made the amino acids convenient to be used as the substrates for the growth of heterotrophic selective deuterated organisms as a source of selective deuterated proteins.