Isolation and characterisation of chemotactic mutants of Chlamydomonas reinhardtii obtained by insertional mutagenesis.

The swimming behaviour of the green flagellated protist Chlamydomonas reinhardtii is influenced by several different external stimuli including light and chemical attractants. Common components are involved in both the photo- and chemo-sensory transduction pathways, although the nature and organisation of these pathways are poorly understood. To learn more about the mechanism of chemotaxis in Chlamydomonas, we have generated nonchemotactic strains by insertional mutagenesis.

Study of Molecular Karyotypes in Amoeboaphelidium protococcarum,the Endotrophic Parasite of Chlorophycean alga Scenedesmus.

On the basis of the pulsed field gel electrophoresis(PFGE) technique, molecular karyotypes in Amoeboaphelidiumprotococcarum (the endotrophic parasite of chlorophycean algae, whichcombines protozoon- and fungus-type characters) were determined. Molecularkaryotypes in the strains X1, X5, and X31, which differ in the host range andoriginate from Western, Central, and Eastern Euro-Asia respectively,demonstrate the intrageneric polymorphism-from 7 to 13 chDNA bands-with theestimated molecular size of 0.3-2.

Isolation and Characterization of Chemotaxis Mutants of Chlamydomonas reinhardtii.

Zoospores of Chlamydomonas reinhardtii exhibit chemotaxis towards maltose, sucrose, xylose, mannitol, and ammonium. Ten independent mutants defective in chemotaxis towards sugars have been isolated. These mutants form five phenotypic classes.

Isolation and structures of five microcystins from a Russian Microcystis aeruginosa strain CALU 972.

Five microcystins were obtained from Microcystis aeruginosa strain CALU 972 isolated from a hepatotoxic water bloom collected in Lake Kroshnosero (Russia). The structure of a new toxin (1) was determined as [Dha7]microcystin-YR by amino acid analyses and fast atom bombardment mass spectrometry, and the toxins 2, 3, 4, and 5 were assigned the structures as [Dha7]microcystin-LR, [D-Asp3,Dha7]microcystin-LR, [Dha7]microcystin-RR, and [D-Asp3,Dha7]microcystin-RR, respectively, by direct comparison with authentic samples.

[Production of the antibiotic-algicide cyanobacterin LU-2 by a filamentous cyanobacterium Nostoc sp].

A strain of cyanobacterium of Nostoc has been isolated, and found to produce a new antibiotic cyanobacterin LU-2. The antibiotic is synthesized by the cyanobnacterium under intensive cultivation conditions in a liquid mineral medium. Cyanobacterin LU-2 is an exometabolite; its maximum accumulation in the medium is achieved at 34 degrees.

Cyanophages.

The description of cyanophages isolated in the USSR is given. The data presented here primarily concern cyanophages of A(L) and S(L) series developing in the cells of Anabaena variabilis strains of Synechococcus species strains, respectively.

[Blattabacterium in the fat body of the Maritime Territory relic roach, Cryptocercus relictus].

Rod-like symbiotic bacteria in the fat body of the cockroach Cryptocercus relictus have a thin cell wall of the Gram-positive type; the nucleoplasm in "diffuse". The septum connected with a massive mesosome is formed during cell division. The bacteria in the host cells are surrounded will several host membranes.

[Effect of photosynthesis on the ultrastructure of a cyanophage during intracellular development].

The particles of the cyanophage A 1(L) are located between the central homogeneous zone and the perpheral thylakoids in cells grown in the conditions optimal for photosynthesis, but the viruses are concentrated in the electron-transparent local zones near or between the thylakoids in cells exposed to 5 . 10(-6) M DCMU.

[Cell cycle characteristics of Chamaesiphon confervicola, a cyanobacterium forming exospores].

A strain of the cyanobacterium Chamaesiphon confervicola was isolated and studied. The strain multiplies by means of exospores, round cells which separate from the parent cell and attach to the substrate with a short pedicle and a mucous pad. The exospore transforms into a cylindrical cell surrounded with a sheath in the process of growth.

Phage-like infectious virus of the green alga Chlorococcum.

A pure culture of the green eukaryotic alga Chlorococcum sp. and a virus infectious for it were isolated. Infection of the culture leads to the destruction of most of the cells, although complete destruction of the culture is not usually observed.

[Bacteria-cortical symbionts of Thichonympha turkestanica, a protozoan from the gut tract of the termite Hodotermes margabicus].

Intracellular symbiotic bacteria of the flagellate Trichonympha turkestanica located in the surface cortical part of the animal cell are described. The cell structure of the symbionts is typical of gramnegative bacteria, but contains also an additional outer membrane. The membrane is an element of the electron-dense structures which have contacts, at many points, with the kinetosomes or membranes surrounding flagella.

[Connection of thylakoids with plasmalemma in the Synechococcus cyanobacterium].

The edges of the thylakoids are connected with the plasmalemma in the cyanobacterium Synechococcus sp., strain 715, this leading to partial compartmentalization of the cytoplasm in the cell.

[Characteristics of the cytodifferentiation of omega-particle symbiotic bacteria from the micronucleus of Paramecium caudata clone M1-48].

The structure of the omega-particle-bacteria, growing in the micronucleus of Paramecium caudatum (Ciliata, Protozoa), was studied by electrom microscopy in the course of their life cycle. The cytoplasm of the spindle-shaped vegetative cells contains a large number of dense particles and transparent regions comprising the fibrillar material. Such cells, via several intermediate stages, are transformed into elongated twisted cells that are regarded as spores.