Introduction of a nitrogen-fixing cyanobacterium into tobacco shoot regenerates

Tobacco (Nicotiana tabacum L.) shoots associated with the nitrogen-fixing cyanobacterium Anabaena variabilis Kütz. (ATCC 29413) were regenerated in mixed cultures of tobacco callus and the cyanobacterium. The cyanobacteria were localized inside the tissues as well as on the surface of regenerated shoots, formed heterocysts, and were capable of acetylene reduction.     

ENDOGENOUS CHANGES OF PHOTOCHEMICAL ACTIVITIES OF SPINACH LEAVES

The activities of green cell-free extracts of spinach leavesin performing photochemical transphosphorylation, photosyntheticphosphorylation, the HILL reaction and the light-induced formationof the endogenous reducing substance (ascorbic acid) were followedin parallel during the growth process of the plant. There wasa certain parallelism between the development of the activitiesof photochemical transphosphorylation, of photo-synthetic phosphorylationand of the HILL reaction, activities being low in the earlierstage of growth, reaching a maximum just before efflorescence,and showing thereafter a more or less sharp decline. The activityin the light-induced formation of endogenous reducing substancewas undetectable for the first 35 day-period of growth, reacheda maximum about one week earlier than the other three activities,and again disappeared after 60 days of growth. (Received September 9, 1960; )     

Hypertrophic Cardiomyopathy as an Oligogenic Disease: Transcriptomic Arguments

Molecular Biology - Hypertrophic cardiomyopathy (HCM) is the most common genetically determined heart pathology and is often accompanied by fatal complications. Today, the traditional view of the...     

Immobilization of a Mixed Culture of Oxygenic Phototrophic Microorganisms on a Chitosan-Based Sorbent for Nutrient Bioremoval

Applied Biochemistry and Microbiology - The immobilization of cells of a mixed culture of the microalgae (MA) Micractinium sp. NAMSU A-19 and cyanobacteria (CB) Synechococcus sp. 1Dp66E-1 on a...     

Population cytology and its role in research of life activity of procaryotes

An historical analysis of the population approach in cytology of microorganisms is presented. Special attention is paid to the structural basis of organization of the developing bacterial population as a holistic self-regulated system featuring cell specialization and cooperation. The structural and functional properties and the proportion of different cell types formed during population development under certain environmental conditions, as well as the structural fundamentals of cell interaction, are proposed as the subject of prokaryote population cytology. The interrelationship of the phenotypical and ultrastructural plasticity concepts in bacteria is discussed. The results of the experiments carried out by the author on cyanobacteria in natural and model plant symbioses are employed as evidence of the efficiency of use of the ultrastructural plasticity-based criteria as markers of the operation of adaptation mechanisms implemented on the subcellular, cellular, and population level.     

Further studies on the role of cell-wall-degrading enzymes in cell-wall loosening in oat coleoptiles

A fungal endo-ß-l,3-glucanase was compared with afungal exo-ß-1,3-glucanase with respect to their effectson elongation and cell-wall extensibility in oat coleoptilesegments. The exo-enzyme enhanced elongation and extensibilityof the cell wall. Its effect was not additive to the effectof indole-3-acetic acid when given together with the latter,at least during 3 hr of incubation. Endo-glucanase showed nosignificant effect on elongation and no interaction with theexo-enzyme. Auxin and exo-glucanase increased extensibilityof the cell wall. The exo-glucanase was separated by isoelectricfocusing. The two fractions which were separated and showedglucanase activity induced elongation and cell wall loosening. (Received March 16, 1970; )     

Cytological study on wheat (Triticum timopheevi Zhuk.) protoplasts

Protoplasts were obtained from tetraploid wheat (Triticum timopheevi Zhuk.) suspension culture by incubation in solution of 1 % pectinase 500, 1 % driselase and 1 % cellulase and cultivated in Schenk and Hildebrandt medium. Freshly isolated protoplasts contained dense cytoplasm and constricted organellae exhibited negative contrast of their membranes. Together with normal protoplasts huge multinucleate protoplasts were present in the population. 3 h after plating, the cytoplasm showed normal appearance, the negative contrast of membranes was not evident any longer. Cisternae of endoplasmic reticulum and Golgi apparatus were numerous. There were some vesicles and fibres on the protoplast surface. 8 d after plating, many dividing cells were found out and cell clumps arosen in this way were present in the culture. Some of the protoplasts particularly those originally multinucleate ones were upset.     

Associations between the White Sea invertebrates and oxygen-evolving phototrophic microorganisms

Eleven species of White Sea invertebrates (sponges, actinians, hydroids, polychaetes, and nudibranch mollusks) were tested for the presence of associated oxygen-evolving phototrophic microorganisms (OPM) (microalgae and cyanobacteria). Two main approaches were applied: (a) light and electron microscopy of intact samples and fixed preparations of invertebrates, and (b) isolation of microorganisms from samples of invertebrates after mild surface sterilization. The obtained results lead to conclusions on the formation of multicomponent associations by White Sea invertebrates and OPM based on the following data: (1) isolation of 27 cultures of OPM from eight species of invertebrates (sponges, hydroids, polychaete trochophore larva), (2) specificity of association between epibiontic communities of microorganisms and macroorganisms within the same biotope, and (3) spatial integration of micro- and macropartners resulting in the formation of morphological structures within the interorganismic contact zones.     

Evolutionary history of tall fescue morphotypes inferred from molecular phylogenetics of the <Emphasis Type="Italic">Lolium</Emphasis>-<Emphasis Type="Italic">Festuca</Emphasis>species complex

Background  

The agriculturally important pasture grass tall fescue (Festuca arundinacea Schreb. syn. Lolium arundinaceum (Schreb.) Darbysh.) is an outbreeding allohexaploid, that may be more accurately described as a species complex consisting of three major (Continental, Mediterranean and rhizomatous) morphotypes. Observation of hybrid infertility in some crossing combinations between morphotypes suggests the possibility of independent origins from different diploid progenitors. This study aims to clarify the evolutionary relationships between each tall fescue morphotype through phylogenetic analysis using two low-copy nuclear genes (encoding plastid acetyl-CoA carboxylase [Acc1] and centroradialis [CEN]), the nuclear ribosomal DNA internal transcribed spacer (rDNA ITS) and the chloroplast DNA (cpDNA) genome-located matK gene. Other taxa within the closely related Lolium-Festuca species complex were also included in the study, to increase understanding of evolutionary processes in a taxonomic group characterised by multiple inter-specific hybridisation events.     

Comparison of homoeolocus organisation in paired BAC clones from white clover (<Emphasis Type="Italic">Trifolium repens</Emphasis> L.) and microcolinearity with model legume species

Background  

White clover (Trifolium repens L.) is an outbreeding allotetraploid species and an important forage legume in temperate grassland agriculture. Comparison of sub-genome architecture and study of nucleotide sequence diversity within allopolyploids provides insight into evolutionary divergence mechanisms, and is also necessary for the development of whole-genome sequencing strategies. This study aimed to evaluate the degree of divergence between the O and P' sub-genomes of white clover through sequencing of BAC clones containing paired homoeoloci. The microsyntenic relationships between the genomes of white clover and the model legumes Lotus japonicus and Medicago truncatula as well as Arabidopsis thaliana were also characterised.