Antimicrobial agents

The antimicrobial effectivity of 32 derivatives and analogues of 10-(4-methylpiperazino)-10,11-dihydrodibenzo(b,f)thiepine was investigated and it was found that substituents in rings A and C and in the piperazine residue affect the antimicrobial potency of the compound. The derivative with the chlorine atom in position 3 was found to be most active in suppressing microbial growth. Substitution with chlorine of the ring C in positions 6, 7 and 8 produced derivatives with highest tuberculostatic activity. The growth of Gram-negative microorganisms (with the exception ofKlebsiella pneumoniae), as well as of fungiTrichophyton mentagrophytes, Candida albicans andAspergillus niger, was not suppressed by any of the derivatives. The antimicrobial effect of the active derivatives was demonstrated on strains ofStreptococcus haemolyticus, Staphylococcus pyogenes aureus, Mycobacterium tuberculosis, Klebsiella pneumoniae andSaccharomyces pastorianus.     

Application of association coefficients for estimating the mean similarity between sets of vegetational relevés

General rules for the use of all kinds of association coefficients for the direct computation of mean similarity between sets of vegetational relevés are given in the present paper. In the table the main kinds of association coefficients used in plant sociology are listed according toSokal andSneath (1963) and the corresponding formulas for direct computation of the mean similarity between and within sets of relevés are given.     

Biosynthesis of subviral oncogenic particles (virosomes) in mitochondria of rous sarcoma and Rauscher murine leukemia cells

Summary Experimental evidence for the presence and biosynthesis of subviral, leukemogenic particles in the isolated mitochondria of spleen cells of mice infected with Rauscher murine leukemia (RML) virus is presented. These subviral particles sediment at a density of 1.27–1.29 g/ml and induce splenomegaly and RML three weeks after i.v. or i.p. administration to white mice. Virosomes have been labelled with [³²P]phosphate in the isolated mitochondria from RML spleen cells and high molecular weight (70S) [³²P]RNA has been isolated from these subviral, leukemogenic particles. Rauscher virus group specific antigens were detected by immunodiffusion in the inner membrane and matrix fraction of the mitochondria of RML spleen cells. These results together with our earlier findings strongly suggest that mitochondria of the transformed cells participate in the biosynthesis of RNA tumor viruses. Possible mechanism of the penetration of viral genetic information of RNA tumor viruses into mitochondria of tumor cellsin vivo is discussed.     

Ultrastructure of meristematic epidermal cells of maize root under water deficit conditions

Summary Structural components of meristematicZea mays primary root epidermal cells were observed after osmotic stress of the nutrient medium (12.5 atm.) and after rehydration. After non-lethal osmotic stress (24 hours), aggregation of nuclear chromatin, parallel ER arrangement, and reduction of mitochondrial cristae were found. Increased number of Golgi cisternae indicated vesicle production inhibition, and microtubules were absent in treated cells, although plastid structure remained unchanged. After lethal osmotic stress (48 hours), fragmentation of cytoplasmic membranes and a more severe structure damage of all cellular components occurred. Structure of the nucleus, mitochondria, Golgi apparatus and microtubules reappeared in the cells after rehydration. The only new feature of these cells was occurrence of smooth ER, which may indicate that the ER system has acquired a different function in regenerated cells.     

Improvement of the method of sap flow rate determination in full-grown trees based on heat balance with direct electric heating of xylem

Several improvements of the method of sap flow rate determination in full-grown trees elaborated by the authors are described. The method is based on heat balance with direct electrical heating of the xylem. The accuracy of the relationship for the calculation of flow rate was improved, the influence of unevennesses of flow in different annual rings was reduced. A method of extrapolation of the results obtained by measuring an individual xylem segment against the whole tree and of interpolation to a unit segment was elaborated, a simplified method of connecting the electrodes supplying the thermal input to the segment is described and an indicator of the relative water content of the xylem was derived.     

Electronmicroscopic comparison of the acid-fast and non-acid-fast strain ofMycobacterium phlei

Ultrastructure of the acid-fast PA strain ofMycobacterium phlei and its non-acid-fast PN mutant was studied in an electron microscope. Results of electronmicroscopic studies were supplemented with observation under an optical microscope, cultivation and chemical analysis of the wall mucopeptide. The effect of lysozyme and glycine on ultrastructure of cells of these strains was also followed. Electron microscopy revealed main differences in thickness and structure of cell walls, in intracellular membraneous system and in shape of rods of the studied strains.     

Botanische Miscellen

Ohne Zusammenfassung     

Sporulation of protoplasts

Vegetative cells ofBacillus megaterium formed protoplasts in a sucrose-stabilized medium under the influence of lysozyme. The protoplasts sporulated during subsequent incubation. The morphological properties, germination, resistance to u. v. irradiation and thermo-resistance of protoplast spores were the same as with normal cells. It thus appears that in the later sporulation stages the spore formation occurs, without participation of the sporangium cell wall.     

Changes in ATPase and SDH reactions of the rat extrafusal and intrafusal muscle fibres after preincubations at different pH

Summary The dependence of adenosine-triphosphatase (ATPase) and succinic dehydrogenase (SDH) histochemical reactions on the pH of the preincubation medium was studied in serial cross sections of 1- to 6-month-old rat extensor digitorum longus (EDL) and soleus (SOL) muscles.The use of a wide spectrum of pH values confirmed the previous results showing that: (1) according to their ATPase and SDH reactions 3 types of extrafusal muscle fibres, i.e., fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG) and slow-twitch oxidative (SO) and 3 types of intrafusal muscle fibres, i.e. typical and intermediate nuclear bag fibres and nuclear chain fibres were observed; (2) only acid preincubation (pH 4.35) is necessary to demonstrate the reversal of the ATPase reaction; while (3) alkali preincubation (pH 10.4) does not provide any new important information as compared with ATPase without preincubation. Furthermore, it was shown that: (4) fast-twitch muscle fibres exhibited high ATPase activity on preincubations at pH 4.9 to 10.4, slow-twitch fibres had very high ATPase activity on preincubation at pH 4.3 and 4.5; (5) after preincubation at pH 4.5 two types of FOG fibres were observed, differing in their ATPase activity; (6) in both muscles there were fibres with intermediate ATPase activity both after acid and/or alkali preincubations; (7) the intrafusal muscle fibres exhibited some specific characteristics when compared with extrafusal fibres.In contrast to the ATPase reactions, SDH activity was decreased equally, in both extra- and intrafusal fibres, with increasing acidity and alkality of the preincubation medium.