Molecular characterization and therapeutic potential of a marine bacterium Pseudoalteromonas sp. KMM 701 alpha-galactosidase

An alpha-galactosidase capable of converting B red blood cells into the universal blood type cells at the neutral pH was produced by a novel obligate marine bacterium strain KMM 701 (VKM B-2135 D). The organism is heterotrophic, aerobic, and halophilic and requires Na+ ions and temperature up to 34 degrees C for its growth. The strain has a unique combination of polysaccharide-degrading enzymes. Its single intracellular alpha-galactosidase exceeded other glycoside hydrolases in the level of expression up to 20-fold. The alpha-galactosidase was purified to determine the N-terminal amino acid sequences and new activities. It was found to inhibit Corynebacterium diphtheria adhesion to host buccal epithelium cell surfaces with high effectiveness. The nucleotide sequence of the homodimeric alpha-galactosidase indicates that its subunit is composed of 710 amino acid residues with a calculated Mr of 80,055. This alpha-galactosidase shares structural property with 36 family glycoside hydrolases. The properties of the enzyme are likely to be highly beneficial for medicinal purposes.

[Properties of Corynebacterium diphtheriae cultivated in the medium prepared from inedible raw materials]

A nutrient medium for the cultivation of C. diphtheriae toxigenic strain was developed on the basis of raw materials unsuitable for use as foodstuffs and its main physico-chemical and cultivation properties were studied. The morphological, cultural, biochemical and toxigenic properties of C. diphtheriae cultivated in the experimental medium with horse serum were evaluated. As revealed in this study, C. diphtheriae retained their properties after prolonged cultivation and storage in the newly developed medium, both liquid and with agar added. The medium has a number of advantages: it is economical, raw materials for its production are readily available, the medium is free of ballast substances.

Patterns of adherence to HEp-2 cells and actin polymerisation by toxigenic Corynebacterium diphtheriae strains

Corynebacterium diphtheriae strains displayed different degrees of attachment to HEp-2 cell monolayers with two distinct adherence patterns, termed localised (LA) and diffuse (DA). The LA phenotype predominated over the DA phenotype. The non-sucrose fermenting strains expressing DA pattern adhered mostly with high index values (> or =10bact/cell). Low adhesion index (<10bact/cell) was mainly observed among sucrose fermenting strains. The fluorescein isothiocyanate (FITC)-labelled phalloidin assay (fluorescent-actin staining test) showed positive results for microorganisms of both LA and DA phenotypes. The FITC-labelled C. diphtheriae non-fimbrial surface proteins 67-72p interacted directly with HEp-2 cell membranes. Therefore, toxigenic C. diphtheriae exhibited LA and DA adherence patterns and ability to induce actin polymerisation. The experimental evidences also pointed to 67-72p as putative adhesins of C. diphtheriae to HEp-2 cells.

[Heteromorphism of the corynebacteria. III. D- (dark) and C- (clear) cell types and multiseptate specimens]

A population of Corynebacterium diphtheriae may consist of cells with accented (osmiophilic) cytoplasm (cells of the "dark" type, or D type) and cells with cytoplasm having no pronounced osmiophilic properties (cells of the "clear" type, or C type). The divergence of the population into cells of the D and C types occurs at the stage of cell division, the original mother cell being able to divide into 2 or more individual cells belonging to different types (elongated multiseptate cells). At the same time no morphological disturbances in septation may be observed. The ability of each type of cells for division into the corresponding individual daughter cells indicates their being biologically valid. The mixed (D--C) population of Corynebacterium diphtheriae is considered to be a sign of the dissociation of bacterial culture.

Three variants of Corynebacterium diphtheriae subsp. mitis (Belfanti) isolated from a throat specimen

Three variants of a Corynebacterium diphtheriae subsp. mitis strain belfanti, two toxigenic (phage types 7 and 11) and one nontoxigenic (phage type 7), were simultaneously isolated from the throat of an adult.

[The species C. diphtheriae]

Corynebacteria (C. diphtheriae var. gravis, mitis, minimus, intermedius, C. belfanti, C. ovis, C. ulceraus) producing diphtheria toxin are found as variants sharply differing from one another morphologically (from long branching rods to coccobacilli), culturally, biochemically and by other signs. The toxin synthesis in them was determined by genetically heterogeneous prophages tox+; tox+ virus exchange is possible between the corynebacteria. Since production of specific toxin, the cardinal sign of C. diphtheriae species, is connected with the genoms of genetically heterogeneous viruses tox+, the circle of whose hosts is very wide, it can be supposed that there is no genetically homogeneous taxonomic category "diphtheriae species". Several species of corynebacteria--lysogenized (toxigenic) or capable of being lysogenized (nontoxigenic) with tox+ viruses are included into the composition of the corynebacteria groups which medicine considers as "species" for over 80 years. A possiblity of becoming a diphtheria causative agent is determined by the capacity of corynebacteria to become infected with the circle of viruses tox+ the DNA of which can become stably integrated with the gene of this bacterium. The mentioned approach to taxonomy is possibly applicable to microorganisms in which the pathogenicity signs (the toxin) were determined, as in C. diphtheriae, in the virus genoms (Bac. botulinus).

Structure of wet specimens in electron microscopy. Improved environmental chambers make it possible to examine wet specimens easily

Several recent technological advances have increased the practicality and usefulness of the technique of electron microscopy of wet objects. (i) There have been gains in the effective penetration of high-voltage microscopes, scanning transmission microscopes, and high-voltage scanning microscopes. The extra effective penetration gives more scope for obtaining good images through film windows, gas, and liquid layers. (ii) Improved methods of obtaining contrast are available (especially dark field and inelastic filtering) that often make it possible to obtain sufficient contrast with wet unstained objects. (iii) Improved environmental chamber design makes it possible to insert and examine wet specimens as easily as dry specimens. The ultimate achievable resolution for wet objects in an environmental chamber will gradually become clear experimentally. Resolution is mainly a function of gas path, liquid and wet specimen thickness, specimen stage stability, acceleration voltage, and image mode (fixed or scanning beam) (13). Much depends on the development of the technique for controlling the thickness of extraneous water film around wet objects or the technique for depositing wet objects onto dry, hydrophobic support films. Although some loss of resolution due to water or gas scattering will always occur, an effective gain is anticipated in preserving the shape of individual molecules and preventing the partial collapse that usually occurs on drying or negative staining. The most basic question for biological electron microscopy is probably whether any living functions of cells can be observed so that the capabilities of the phase contrast and interference light microscopes can be extended. Investigators are now rapidly approaching a final answer to this question. The two limiting factors are (i) maintaining cell motility in spread cells immersed in thin layers of media and (ii) reducing beam radiation damage to an acceptable level. The use of sensitive emulsions and image intensifiers can bring the observation dose below that required to stop cell motility. Use of a timed, pulsed deflector system enables sufficiently short exposures to be obtained to eliminate blurring due to Brownian motion. Environmental chambers have enhanced the possibilities of electron diffraction analysis of minute crystals and ordered biological structures. High-resolution electron diffraction patterns (especially kinematic) of protein crystals can only be obtained in a wet environment. Hence, it may now be possible to obtain undistorted images of protein molecules. Moreover, by subjecting diffraction patterns to image-iterative techniques (56), it will be possible to phase the electron diffraction patterns to give a calculated image with a higher resolution than that which can be produced by electron microscope objective lenses. Environmental chambers offer exciting prospects for the determination of water structure and water and ice nucleation (atmospheric science). Nucleation data near the molecular level have been badly needed for some time. The application of environmental chambers in industrial chemistry, for example, in studies of polymerization, catalysis, and corrosion, are awaiting exploration. They offer an unusual approach to measurements of reaction kinetics through images that should be both sensitive and rapid.

Park-Williams number 8 strain of Corynebacterium diphtheriae

Five clones of the Park-Williams number 8 strain of Corynebacterium diphtheriae, previously maintained in separate laboratories, were examined for their colonial and biochemical properties, for the restriction and modification system which operates to obscure their lysogeny, and for their capacity to produce large amounts of toxin under ordinary laboratory conditions. The phenotypes of their phage, P, produced in strain 603 and C7 (P.603 and P.C7) differ both as to stability to storage in the cold and to inactivation by antiphage serum. Evidence for a high degree of stability in the integration of P prophage in the PW8 genome is presented.

Corynebacterium diphtheriae and its relatives

Images

Presence of rhapidosomes in various species of bacteria and their morphological characteristics

Rod-shaped structures have been observed in cells of Pseudomonas, Photobacterium, Proteus, and Saprospira by use of the negative-contrast stain. These structures, referred to as rhapidosomes, appear to be normal components of these cells. Other bacteria including Escherichia, Salmonella, Shigella, Klebsiella, Micrococcus, Bacillus, Mycobacterium, Rhodospirillum, and Hydrogenomonas genera failed to reveal these structures. The rhapidosomes of Saprospira were found to consist of two rods, one encasing a narrower, longer structure. In contrast, the rhapidosomes of Pseudomonas, Proteus, and Photobacterium were without the rigid inner structure, but were occasionally seen filled with a homogeneous material as observed by the negative stain. Ultrathin sections of Pseudomonas cells indicate that these rhapidosomes are embedded within or are in close association with the nucleoplasm.

An electron microscope study of thin sections of Haemophilus vaginalis (Gardner and Dukes) and some possibly related species

The line structure of Haemophilus vaginalis (Gardner and Dukes 1955) was compared with that of four, possibly related species (Butyribacterium rettgeri, Corynebacterium diphtheriae var. mitis, Lactobacillus acidophilus, Haemophilus influenzae) and an unrelated species, Neisseria haemolysans, which had shown a similar degree of Gram-variability as that of H. vaginalis. Although H. vaginalis was first described as a Gram-negative rod, its fine structure, particularly that of cell wall and septa, was more like that of Gram-positive organisms. Also N. haemolysans had a fine structure close to that of Gram-positive organisms, and its typical Gram-positive cell wall varied in. thickness from one cell to another.The study did not solve the problem of the classification of the so-called H. vaginalis, but the appearance of the few strains studied in the electron microscope suggests that it: should be included in Corynebacterium or Butyribacterium rather than in Lactobacillus.