Loss and gain of GroEL in the Mollicutes.

GroEL is a chaperone thought of as essential for bacterial life. However, some species of Mollicutes are missing GroEL. We use phylogenetic analysis to show that the presence of GroEL is polyphyletic among the Mollicutes, and that there is evidence for lateral gene transfer of GroEL to Mycoplasma penetrans from the Proteobacteria. Furthermore, we propose that the presence of GroEL in Mycoplasma may be required for invasion of host tissue, suggesting that GroEL may act as an adhesin-invasin.

Fourier transform infrared spectroscopy as a new tool for characterization of mollicutes.

Fourier transform infrared (FT-IR) spectroscopy is a convenient physico-chemical technique to investigate various cell materials. Bacteria of class Mollicutes, identified by conventional methods, as Mycoplasma, Acholeplasma and Ureaplasma genera were characterized using this method. A data set of 74 independent experiments corresponding to fourteen reference strains of Mollicutes was examined by FT-IR spectroscopy to attempt a spectral characterization based on the biomolecular structures. In addition to the separation of Mollicutes within the lipidic region into five main clusters corresponding to the three phylogenetic groups tested, FT-IR spectroscopy allowed a fine discrimination between strains belonging to the same species by using selective spectral windows, particularly in the 1200-900 cm(-1) saccharide range. The results obtained by FT-IR were in good agreement with both taxonomic and phylogenetic classifications of tested strains. Thus, this technique appears to be a useful tool and an accurate mean for a rapid characterization of Mollicutes observed in humans.

[Monosaccharide composition of some Mollicutes]. / Monosakharydnyi sklad poverkhnevykh struktur deiakykh Molikutiv.

When studying a small group of mollicutes which interact in different way with the host organism (Mycoplasma fermentans PG18--is considered a commensal of the human urogenital tract, and sometimes manifests as AIDS cofactor, Acholeplasma laidlawii PG8 is saprophytic but it is connected with various pathologies in human organism, A. laidlawii var. granulum 118--agent of the yellow of cereals--palegreen dwarfness) the author has found the carbohydrate composition of their cell surface. Glycocalix of all three representatives proved to be rather various. Biochemical investigation methods were used to establish the presence of galactosamine, glucosamine, minor quantity of rhamnose, ribose, arabinose, xylose, mannose as well as considerable share of fucose, galactose, glucose. Qualitative and quantitative content of monosaccharide composition of the glycocalix of certain species of mollicutes which have different ecological niches is studied in the work and the role of some sugars in performing certain important functions is discussed.

The motility of mollicutes.

Recent experiments show that the conformation of filament proteins play a role in the motility and morphology of many different types of bacteria. Conformational changes in the protein subunits may produce forces to drive propulsion and cell division. Here we present a molecular mechanism by which these forces can drive cell motion. Coupling of a biochemical cycle, such as ATP hydrolysis, to the dynamics of elastic filaments enable elastic filaments to propagate deformations that generate propulsive forces. We demonstrate this possibility for two classes of wall-less bacteria called mollicutes: the swimming of helical-shaped Spiroplasma, and the gliding motility of Mycoplasma.

Evidence of intermolecular recombination between extrachromosomal DNAs in phytoplasma: a trigger for the biological diversity of phytoplasma?

Recombination among bacterial extrachromosomal DNAs (EC-DNAs) plays a major evolutionary role by creating genetic diversity, and provides the potential for rapid adaptation to new environmental conditions. Previously, a 7 kbp EC-DNA, EcOYW1, with a geminivirus-like rolling-circle-replication protein (Rep) gene was isolated and characterized from an original wild-type line (OY-W) of onion yellows (OY) phytoplasma, an endocellular cell-wall-less prokaryote that inhabits the cytoplasm of both plant and insect cells. EcOYW1, found in OY-W, was not present in a mild-symptom line (OY-M) derived from OY-W. A 4 kbp EC-DNA, pOYW, was also isolated and characterized from OY-W, and its pLS1-plasmid-like rep gene was expressed. This paper describes the isolation and sequencing of an EC-DNA of 5560 nt, EcOYW2, from OY-W, and its counterpart EC-DNA of 5025 nt, EcOYM, from OY-M. EcOYW2 and EcOYM contained seven and six ORFs, respectively. They both encoded a geminivirus-like Rep and a putative single-stranded-DNA-binding protein (SSB). Southern blot analysis indicated that no more EC-DNAs with a rep gene exist in either OY-W or OY-M, which means that the complete set of EC-DNAs has been cloned from the OY-W and OY-M lines of OY phytoplasmas. Sequence analysis revealed that both EcOYW2 and EcOYM have chimeric structures of previously characterized EcOYW1 and pOYW, suggesting that they have a recombinational origin. This is the first evidence of intermolecular recombination between EC-DNAs in phytoplasma. The possible implications of these findings in increasing the biological diversity of phytoplasma are discussed.

[Discovery of the relationship between carbohydrate determinants of mollicute glycocalyx and affinity of microorganisms, and conditions for their existence]. / Vyiavlennia zv'iazku mizh vuglevodnymy determinantamy glikokaliksu molikutiv i sporidnenykh z nymy mikroorganizmiv ta umovamy ïkh isnuvannia.

As a result of comparative analysis of interaction intensity of plant lectins, specific to certain monosaccharides with surface glycopolymers of philogenetically close groups of microorganisms--mollicutes and representatives of group Bacillus--Lactobacillus--Streptococcus the authors have established common features: availability of alpha- and beta-D-galactose, sialic acids, L-fucose, N-acetylglucosamine, alpha-N-acetyl-D-galactosamine and alpha-D-mannose in their glycocalyx, that is a phenotypical manifestation of genetic relations between these microorganisms. The dependence between the availability of sialic acids and L-fucose in the composition of terminal structures of microorganisms glycocalyx and their capacity to occupy certain ecological niches have been found out.

[The monosaccharide composition of the glycocalyx in Mollicutes and phylogenetically related bacteria in the genus Bacillus]. / Monosakharydnyi sklad hlikokaliksu deiakykh molikutiv i filohenetychno blyz'kykh ïm bakterii rodu Bacillus.

A number of monosaccharides composing the glycocalix carbohydrates of some Mollicutes (Mycoplasma pneumoniae FH, M. hominis PG21, M. fermentans PG18, Acholeplasma laidlawii PG8, A. laidlawii var. granulum st. 118) and phylogenetically related bacteria from the genus Bacillus (Bacillus cereus 89, B. cereus DM423, B. subtilis 1/2, B. licheniformis 31, B. licheniformis 49) were detected using plant lectins of definite carbohydrate specificity labelled by colloid gold. The structure of extracellular glycopolymers of microorganisms was discussed concerning their role in the adhesion process and their specializations in colonization of the appropriate organs and tissues of macroorganisms as well as the action of probiotics on the basis of bacteria from the genus Bacillus. It was marked, that the mollicute cells typically interacted with all vegetable lectins tested while bacilli studied bind certain lectins only. The surface carbohydrates prevailing in monosaccharides from tested one for superficial structures of Bacillus pathogenic strains were: sialic acid, beta-D-galactose and alpha-N-acetyl-D-galactosamine, while L-fucose and alpha-D-glucose were observed in insignificant quantity or were absent. The nonpathogenic Bacillus strains being a basis of biopreparations were distinguished by the insignificant amount of sialic acid and other monosaccharides in the composition of carbohydrates of their glycocalix. Thus, as a result of research it was confirmed, that the superficial glycopolymers of Mollicutes and some related bacilli were alike as to presence of some monosaccharides that depended on taxonomic position of microorganisms and their biological activity.

Serological and molecular characterization of Mesoplasma seiffertii strains isolated from hematophagous dipterans in France.

Three strains of nonhelical mollicutes previously isolated in France from two different mosquitoes and one tabanid fly were designated strains Ar 2328 (isolated from Aedes detritus), Ar 2392 (isolated from Aedes caspius), and CP 13 (isolated from Chrysops pictus). All of these strains exhibited properties of the genus Mesoplasma, a recently described genus of non-sterol-requiring mollicutes isolated from plants and insects. The results of metabolism inhibition and growth inhibition tests revealed that these strains and Mesoplasma entomophilum TAC or Mesoplasma florum L1 were not serologically related, but all three dipteran strains reacted strongly with Mesoplasma seiffertii F7T (T = type strain) antibodies. Using metabolism inhibition and growth inhibition tests, we found that the dipteran strains were related to each other and to strain F7T but were not identical. We also found that they were able to multiply and persist in the central nervous systems of suckling mice inoculated intracerebrally, a property that makes their use as biological control agents for pest dipterans inadvisable. Scanning electron microscopy revealed marked differences in the morphologies of the colonies of the different strains on SP4 solid medium. The levels of DNA-DNA homology for strains Ar 2328, Ar 2392, CP 13, and F7T were more than 70%, indicating that these strains are closely related members of the same species, M. seiffertii. In addition, one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that each strain produced about 40 protein bands. This technique also revealed differences between strains. Using the coefficient of Smeath-Jacquart, we constructed a dendrogram that allowed us to estimate of the levels of relatedness of these four strains. The results which we obtained were confirmed by two-dimensional protein electrophoresis results.

Possible monosaccharide composition of glycopolymers located on the external side of membranes of cells of some mollicutes.

Monosaccharide composition of glycopolymers of five mollicutes (Mycoplasma pneumoniae FH, M. hominis PG 21, M. fermentans PG 18, Acholeplasma laidlawii PG 8 and A. laidlawii var. granulum 118) integrated with their membrane has been studied by means of nine plant lectins with certain carbohydrate specificity labelled with colloid gold. Monosaccharide composition of glycopolymers depends both on the mollicute species and on its capacity to evoke diseases in different microorganisms. Thus genetically relative A. laidlawii PG 8 (saprophytic microorganism) and A. laidlawii var. granulum 118 (an agent of pale-green dwarfness of cereals) have the ratio between N-acetyl-D. galactosamine and N-acetyl-D-glucosamine 2:1 and 1:2, respectively. Large amounts of such exotic sugar as L-fucose have been found in M. hominis PG 21, M. fermentans PG 18 and A. laidlawii PG 8. L-fucose plays the basic role in disguising cells of these mollicutes in human organism (as O(H)-group blood erythrocytes), which permits these mollicutes disseminating through the whole organism. The composition of extracellular glycopolymers of mollicutes is discussed to reveal their role in the processes of adhesion and specialization (organotropism) of these microorganisms in populating the corresponding organs and tissues of macroorganisms.

[Soluble and semisoluble lectins from mollicutes and their possible functions]. / Rozchynni ta napivrozchynni lektyny molikutiv i ïkh mozhlyvi funktsiï.

When studying mollicute lectins it was established that Acholeplasma laidlawii PG-8 synthesizes two half-soluble lectins one of which is specific to N-acetyl-D-glucosamine, and the other--to D-glucosamine.HCl; phytopathogenic strain A. laidlawii var. granulum 118 produced 4 lectins one of which is soluble and specific in respect to fructose-1.6-diphosphate, the rest three lectins are half-soluble and specific to one of the sugars--D-galactosamine.HCl, rafinose and D-glucosamine.HCl. In Mycoplasma pneumoniae FH all the four lectins found in the culture liquid have been classified as half-soluble, specific to one of carbohydrates--D-galactosamine.HCl, talose, N-acetyl-neuramine acid and D-glucose; M. capricolum Cal. Kid. synthesizes four lectins; two of them being defined as soluble (one of the lectins is, respectively, specific to talose and D-glucosamine.HCl, two others, as half-soluble, specific to one of sugars--rafinose or D-glucose. The results obtained permit a conclusion to be made that the half-soluble lectins of mollicutes, on the one hand, are the factors of adhesion on the corresponding organs of macroorganism and, on the other hand take part in the transport of substances from without into the microorganism cell. Soluble lectins determine pathogenicity of mollicutes and form with half-soluble lectins a single chain to providing the mycoplasma cells with nutrients and to protect them from the action of the macroorganism immune system.

Membrane properties of a plant-pathogenic mycoplasmalike organism.

In terms of biosystematics, the plant-pathogenic mycoplasmalike organisms (MLOs) have been tentatively placed into the class Mollicutes. Certain physiological tests have been used to distinguish families within this class: the sterol-nonrequiring Acholeplasmataceae differ from the sterol-requiring Mycoplasmataceae in that the former are more resistant to lysis by digitonin and more sensitive to lysis in hypotonic salt solutions. To test MLOs for these membrane properties and thus assist in their definitive classification, a dot-blot microassay procedure was used to detect nucleic acids released from lysed cells. The results show that MLOs resemble acholeplasmas grown in the absence of sterols in that they are resistant to digitonin and sensitive to hypotonic salt solutions. The MLOs can be differentiated from acholeplasmas grown without sterols by their greater resistance to lysis in hypotonic sucrose solutions.