First solid state alkaline-earth complexes of monensic acid A (MonH): crystal structure of [M(Mon)2(H (2)O)2] (M = Mg, Ca), spectral properties and cytotoxicity against aerobic Gram-positive bacteria.

Alkaline-earth metal complexes of the monoanionic form of the polyether ionophore monensin A were isolated for the first time in solid state and were structurally characterized using various spectroscopic methods (IR, NMR, FAB-MS). The stoichiometric reaction of monensic acid (MonH) with M(2+) (M = Mg, Ca) in the presence of an organic base leads to the formation of mononuclear complexes of composition [M(Mon)(2)(H(2)O)(2)]. The structures of magnesium (1) and calcium (2) monensin complexes in the solid state were established by single crystal X-ray crystallography. The complexes crystallize as [Mg(Mon)(2)(H(2)O)(2)]x5MeCN (1) and [Ca(Mon)(2)(H(2)O)(2)]xH(2)Ox5MeCN (2) in the monoclinic P21 space group. The alkaline-earth metal ion is placed in a distorted octahedral environment, defined by two monensin anions acting as bidentate ligands in the equatorial plane of the complex as well as by two water molecules occupying the axial positions of the inner coordination sphere. The bactericidal activity of 1 and 2 was evaluated against aerobic Gram-positive microorganisms applying the double layer agar hole diffusion method.

Amino sugar and amino acid constituents of the cell walls of the extremely halophilic cocci.

Cell wall hydrolysates of nine strains of extremely halophilic cocci all contained gylcine, glucosamine, galactosamine, and gulosaminuronic acid. Muramic acid was not present in any of the strains.

Effect of viscosity on bacterial motility.

The behavior of a number of motile flagellated bacteria toward viscosity characteristics of their fluid environments was observed. All showed an increase in velocity (micrometers per second) in more viscous solutions. Velocity reached a maximum at a characteristic value, however, and thereafter decreased with higher viscosities. Peritrichously flagellated bacteria had maximum velocities at higher viscosities than polarly flagellated bacteria. Effects of temperature, and possible utilization of chemical constituents in the viscous solutions, were studied and found to be negligible factors under the experimental conditions used. Different agents produced the same phenomenon, thus indicating that there probably were no chemically induced metabolic effects. Loss of available water and the possibility of a variable energy supply to the flagellar propulsive system were considered but are believed minimal. Theoretically derived thermodynamic equations were utilized and suggest that the conformation of the flagellar helix affects efficiency of propulsion. Such a relationship between helix waveform and velocity was experimentally observed with Thiospirillum jenese.

Effect of lysozyme treatment on cell wall ultrastructure in Sarcina flava.

Treatment of Sarcina flava NCTC 7503 cells with lysozyme resulted in incomplete removal of the cell wall and imparted a layered appearance to it.

Microorganisms in unamended soil as observed by various forms of microscopy and staining.

A light-diffraction microscope was modified to allow sequential viewing of the microorganisms in a soil smear by transmitted, reflected, and reflected-polarized incandescent light and by reflected ultraviolet light. Observations were also made by conventional incandescent and ultraviolet transmitted-light microscopy. All results for the various forms of bright-field microscopy with stained and unstained soils were in agreement, but they differed from the results obtained for two types of ultraviolet-fluorescence microscopy. The latter proved to be nonspecific for in situ soil microorganisms. Capsule-like areas were noted surrounding many of the resident microbial cells of soil when viewed by the various forms of bright-field microscopy. These areas could not be stained or removed by a variety of treatments, but they apparently often did take up stain after in situ soil growth had been initiated. It was concluded that these areas are not capsules but may represent a structural component of nonmultiplying microbial cells in soil.

Scanning electron and phase-contrast microscopy of bacterial spores.

The three-dimensional immages of free and intrasporangial spores produced by scanning electron microscopy show surface structures not visible by phase-contrast microscopy. Although fine surface detail is not elucidated by scanning electron microscopy, this technique does afford a definitive picture of the general shape of spores. Spores of Bacillus popilliae, B. lentimorbus, B. thuringiensis, B. alvei, B. cereus, and Sarcina ureae have varying patterns of surface ridge formation, whereas spores of B. larvae, B. subtilis, and B. licheniformis have relatively smooth surfaces.

Disruption of bacterial cells by a synthetic zeolite.

The use of a synthetic zeolite (type 4A, Union Carbide Corp., Linde Div., New York, N.Y.) in a procedure for the preparation of pure cell wall fractions proved successful for many gram-positive, gram-negative, and acid-fast bacteria, as well as for some fungi. The technique, however, was found to be limited in effectiveness for Rhodospirillum rubrum, Gaffkya tetragena, and Sarcina lutea, and not applicable to preparations of heat killed microorganisms. The possible mechanisms of zeolite action, together with the effect of the disruptive procedure on the chemical composition of cell wall fragments, were investigated also.

Taxonomy of psychrophilic strains of Bacillus.

The morphological and physiological characteristics of 20 isolates of psychrophilic Bacillus were compared with 29 strains representing nine species of mesophilic Bacillus and 2 strains of Sporosarcina ureae to determine the taxonomic position of the psychrophiles. The psychrophiles formed four distinct groups which were sufficiently different from the mesophiles to warrant their designation as new species of Bacillus. The names B. psychrosaccharolyticus, B. insolitus, B. globisporus, and B. psychrophilus are proposed for the new species.

Fluorescein-labeled beta-glucosidase as a bacterial stain.

Fluorescein isothiocyanate-labeled beta-glucosidase was used as a simple staining reagent with selected gram-positive and gram-negative organisms. Staining in situ appeared to be dependent on the presence of accessible glycosidic-type linkages in the bacterial cell wall. Extensive wall damage or lysis did not occur when stained cells were suspended in washing and mounting solutions. The apparent specificity of labeled enzyme for wall substance was tested by blocking reactions, staining of isolated cell walls, and failure to stain substances lacking appropriate glycosidic linkages. Severe cell wall lesions were produced after prolonged contact with labeled enzyme, and this phenomenon may also be related to staining specificity. Gram-negative organisms and spores were poorly stained unless protected glycopeptide substrate was previously exposed by treatment of cells with thioglycolic acid or dilute alkaline sodium hypochlorite solution. A potential for staining tissues and cell lines may also exist. Some possible applications of labeled enzymes are briefly discussed.