Mire communities of Reykjanes peninsula,SW. Iceland (Plant communities of reykjanes peninsula,part I.)

In Reykjanes peninsula, mainly in the valley of Krísuvík, in all 6 mire associations were found, belonging to the alliancesEriophorion Scheuchzeri andCaricion canescentis-fuscae. Floristic, ecological and physiognomical differeces between the two alliances are discussed. Most of the associations seem to be restricted in their distribution to Iceland.     

Chromosome counts of some Mongolian plants

The paper gives the chromosome numbers of 45 species from 72 Mongolian localities, belonging to the genera:Amygdalus, Asparagus, Astragalus, Cancrinia, Caragana, Chamaerhodos, Chelidonium, Chesneya, Dianthus, Hypecoum, Lathyrus, Lilium, Oxytropis, Papaver, Potentilla, Schizonepeta, Sibbaldia, Thermopsis, Trifolium, Trigonella, Vicia. Chromosome morphology of three species ofChamaerhodos and taxonomical remarks on some other species are added. A new combinationSibbaldia sericea (Grubov) Soják is proposed.     

Serological analysis of eleven strains ofRhizobium japonicum

The present communication reports a serological analysis of eleven strains ofRhizobium japonicum. The slow-diffusing thermostable antigens were found to be suitable for the basic differentiation of the somatic serogroups inRhizobium japonicum. One to three precipitation bands of the slow-diffusing thermostable antigens, one to two bands of the fast-diffusing thermostable antigens and one to three bands of the thermolabile antigens were detectable in the whole cell cultures ofR. japonicum by means of the immunodiffusion technique. Two basic somatic serogroups were differentiated on the basis of the slow-diffusing thermostable antigens. The thermolabile antigens were identical in most of the strains.The author is greatly indebted to Mrs. M. Kabelovà for technical assistance.This investigation forms part of a contribution prepared by the Czechoslovak National Committee for the International Biological Programme (Section PP: Production Processes).     

Antibacterially active substances

Synthesis of two hydroxy-derivatives of nalidixic acid as a result of microbial transformation was demonstrated in certain species of the genusAspergillus. Aspergillus alliaceus produced 7-hydroxy-nalidixic acid andAspergillus niger 6-hydroxy-nalidixic acid. It was demonstrated that the antibacterial activity of both hydroxy-derivatives (tested inEscherichia coli) was lower than that of the initial nalidixis acid.     

The inactivation ofBacillus subtilis transforming DNA by mutagenic agents

The inactivation of three genetic markers inBacillus subtilis transforming DNA by UV rays, nitrous acid and hydroxylamine was studied. The inactivation of markers by UV and HNO₂ was marker specific, whereas the hydroxylamine inactivates the markers approximately to the same degree.     

Physiological properties of microbial population as a basis for graphical solution of multi-stage continuous cultivations

A proposal for a graphical solution of the design of a multi-stage continuous culture system is presented. The holding times in individual stages are derived from the reciprocal values of the growth rate and of the product formation rate and plotted against the cell and product concentrations. Characteristic changes of physiologically significant paramaters are then projected on these production curves. Dedicated to Academican Ivan Málek on the occasion of his 60th birthday     

Ontogenetic development of antibody formation in response to different doses of gram-negative microorganisms in young rabbits

Rabbits at different stages of development were immunized with different doses of heatinactivated suspension ofEscherichia coli 086 andSalmonella paratyphi B. The dynamics and the site of formation of bactericidal and haemolytic antibodies during the primary reaction was investigated. An increase and an acceleration of antibody formation after increasing the dose of antigen was found in the serum and at the cellular level. The magnitude of the response and the rate of the reaction were directly proportional to the age of the experimental rabbits. The site of antibody formation depends on the character, route of administration, antigen dose and age of rabbits. After intraperitoneal and also after intravenous immunization withEscherichia coli andSalmonella paratyphi B antigens the site of antibody production in 15-day-old rabbits was the lymphatic tissue of the intestine, the appendix, and mesenteric lymph nodes. As the antigen dose was increased and the age of rabbits rose, i.e. in correlation with the increase of the antibody response, antibody formation shifted to the spleen which is the chief site of antibody production following immunization by these bacterial antigens from the first month of life of rabbits. In contrast with this type of antigen, after intraperitoneal or intravenous immunization with sheep erythrocytes of new-born or older rabbits antibody formation was concentrated in the spleen. The development of the immunological competence and the significance of intestinal lymphatic tissue as one of peripheral type is discussed.     

Attempt at quantitative analysis of interindividual variability in stress response of leucocyte levels in mice from the viewpoint of control theory

Summary The authors studied the dependence between the ability of systems regulating the level of peripheral leucocytes to damp the fluctuations of this level, occurring under conditions of repeated stressing of the organism by non-specific stress factors (isolation, starvation, handling for blood withdrawal) and the tolerance of the organism to the action of ionizing radiation (summary exposure to X-rays leading to death at repeated irradiation). This regulatory ability was expressed with the aid of the slope (coefficientb) of regression between the leucocytary valuesx _i, fluctuating in time, and the subsequent differences _i ( _i =x _i+1–x _i ). The highest tolerance to lethal action of radiation is correlated to such a regulatory behaviour of the organism at which the time necessary for adaptation of the system is shortest. The authors point out the suitability of the employed regulatory characteristic for the quantitative study of adaptability and resistance of the organism and its relatedness to the damping ratio, used in the automatic control theory.     

Postnatal differentiation of the Golgi apparatus and the dendrites of Purkinje cells of the rat cerebellum

Summary The morphology of postnatal differentiation of the Golgi apparatus, the nucleus, the perikaryon, and the dendrites was studied in Purkinje cells of the rat cerebellum for 30 days after birth using histochemical, histological, and electron microscopic methods.The Golgi apparatus during differentiation undergoes morphological and positional changes. From the 1st to 7th postnatal day, the Golgi apparatus is found in a supranuclear position, and is connected with the axes of differentiating primary dendrites by beam-like processes. From days 8 to 11 this connection disappears, and most of the Golgi apparatus assumes a lateronuclear and infranuclear position. After the 11th or 12th day, the Golgi apparatus is found in perinuclear and peripheral cytoplasmic positions. The formation of granular endoplasmic reticulum occurs in the vicinity of the perinuclear Golgi apparatus. The differentiation of cell and nuclear forms requires approximately 20 days. The morphological changes of differentiation are discussed in relation to the participation of the Golgi apparatus in the differentiation of dendrites and in the formation of the granular endoplasmic reticulum.     

Die wirkung der β-(3-Pyridyl)-propion-und der β-(3-Pyridyl)-acrylsäure auf die Atmung der Wurzeln vonSinapis alba L.

V práci byly studovány rozdíly v ú?innosti kyseliny β-(3-pyridyl)-propionové (VIII) a β-(3-pyridyl)-akrylové (IX) v závislosti na stupni nenasycení pobo?ného ?etězce. Obě kyseliny inhibují r?st ko?ene i hypokotyluSinapis alba L. a zp?sobují inhibici sukcinátdehydrogenázového enzymového systému. Kyselina IX inhibuje zmíněný systém p?ibli?ně na dvojnásobek inhibice kyseliny VIII. Cytochromoxydázový systém z?stává témě? neovlivněn. Na základě experimen tálních výsledk? byla zp?esněna strukturní podmínka fytotoxické aktivity modelových slou?enin typu I v tom smyslu, ?e v?echny slou?eniny této struktury inhibují kromě r?stu také aktivitu sukcinátdehydrogenázového systému.