Basic characteristics of the process of Candida adhesion to human epitheliocytes

The adhesion of fungi belonging to the genus Candida to the epithelial cells of the mouth cavity reached its maximum at pH 6.2-7.0. The process of adhesion had similar dynamics at temperatures of 37 degrees, 28 degrees and 25 degrees C, but the adhesive activity decreased 2 times when temperature dropped from 37 degrees to 25 degrees and 4 times when temperature dropped to 4 degrees C. The introduction of the ions Ca2+ (1 and 10 mM) and Mg2+ (10 mM) led to the increase of adhesion by 80, 100 and 24% respectively. The heating of the fungal cells at 100 degrees C (for 1 hour) and at 63 degrees C (for 2 hours) decreased adhesion to 8 and 24% respectively, and treatment with formaldehyde (for 24 hours) decreased adhesion to 70% of that observed in experiments with live Candida cells.     

The ultrastructural characteristics of Francisella tularensis interaction with Tetrahymena pyriformis

The electron-microscopic study of the interaction of F. tularensis virulent and attenuated strains with infusoria of the species T. pyriformis was dynamically studied. In this study the structural changes of F. tularensis and T. pyriformis cells, as well as their capacity for survival, were revealed. The data on their ultrastructure correlated with the dynamics of the number of both F. tularensis and T. pyriformis: during the whole term of observation the tendency to a slow decrease in the number of F. tularensis was registered with the concentration of T. pyriformis remaining stable. The interaction of F. tularensis with T. pyriformis may be regarded as a variant of commensal, but not antagonistic interactions.     

Adhesiveness of yeast-like fungi in the system "Candida albicans--vaginal epitheliocytes"

The influence of vaginal liquid on adhesive reactions in the system "Candida albicans - vaginal epitheliocytes". Preliminary treatment of C. albicans by mucin, natural or absorbed vaginal liquid resulted in decrease of adhesive activity (p<0.05). C. albicans did not change its adhesive properties in case of preliminary treatment of vaginal epitheliocytes by the same substances. In the system "Candida albicans - vaginal epitheliocytes" vaginal liquid has the expressed antiadhesive effect, which probably belongs to mucin.     

Histochemical characteristics of the epitheliocytes of the avian glandular stomach

A complex histochemical investigation has been undertaken to study the epithelial lining of the glandular stomach in birds having various types of nutrition. The protective barrier of the avian stomach has been found to be characterized as a resistant (mucosal) barrier, with neutral glycoproteins, sialo- and sulphoglycoproteins as its components. Differences in histochemical properties of the epitheliocyte secretion have been described in birds with different types of nutrition. They are connected with various correlation of carbohydrates and proteins in the composition of the micromolecular glycoprotein complex. The data obtained are compared with those concerning the histochemical properties of the stomach in amphibia and reptiles which have the mucous membrane structure similar to that in the avian stomach.     

The ultrastructural characteristics of the interaction of Legionella pneumophila with the infusorian protozoon Tetrahymena pyriformis

In this work the morphological features of the interaction of L. pneumophila virulent strain and T. pyriformis have been studied on the submicroscopic level in the time course of the process. The study has shown the process of the destruction of the bacterial population and the penetration of individual intact Legionella cells from the phagosome into the endoplasm of T. pyriformis after 6-9 hours of interaction in the form of the budding of the phagosome and further multiplication of Legionella in the endoplasm. As revealed in this study, T. pyriformis have two types of phagosomes characterized by different variants of the destruction of Legionella. In T. pyriformis lysosomes-like granules, mitochondria and the granular endoplasmatic network take part in the process of interaction. The process of interaction has been found to end by day 7 in the death of all protozoal cells taking part in interaction.     

Production of cytokines by vaginal epitheliocytes in the process of interaction with dominant and associative microsymbionts

AIM: Study the expression of cytokines by vaginal epitheliocytes in the process of interaction with dominant and associative microsymbionts. MATERIALS AND METHODS: IL-8, IL-6, IL-1beta and TNFalpha expression in response to interaction with heat inactivated Lactobacillus spp., Staphylococcus aureus, Escherichia coli, Corynebacterium spp. or their secretory products in comparison with basal expression of cytokines by vaginal epitheliocytes was studied. Results. Lactobacilli secretory products were shown not to influence the expression of IL-8 and IL-1beta and moderately stimulated IL-6 and TNFalpha expression. Contact of epitheliocytes with heat inactivated lactobacilli increased secretion of IL-8, IL-6 and IL-1beta and reduced TNFalpha production. Secretory products of S. aureus and E. coli caused stimulation of IL-6, IL-1beta production and practically did not change the expression of IL-8 and TNFalpha. Contact of epitheliocytes with heat inactivated S. aureus sup pressed TNFalpha production and had no influence on IL-8, IL-6 and IL-1beta expression, contact with E. colistimulated TNFalpha and IL-1beta expression and suppressed IL-6 expression. Changes in cytokine expression during interaction of epitheliocytes with corynebacteria were largely similar to the results of interaction with lactobacilli except IL-6 production that was markedly stimulated by corynebacteria secretory products. Conclusion. In epithelial-bacterial interactions dominant and associative microorganisms have a differential effect on functional status of mucosal epitheliocytes manifesting in production of cytokines that could be the basis of mucosal immunity regulation.     

The ultrastructural characteristics of the causative agent of melioidosis and its interaction with phagocytes in vivo

The electron microscopic studies have established that the virulent strain of Pseudomonas pseudomallei C-141, an agent of melioidosis, being intraperitoneally administered to guinea pigs, forms in vivo three morphological variants. One variant is capsule-free, while two others have a capsule which in the second variant may be referred by its characters to the microcapsule and in the third one to the macrocapsule. It has been shown that under the interaction of these three morphological variants with the microorganism cells the bacteria of the first and second variants are absorbed by phagocytes, whereas the microbial cells of the third morphological variant are more resistant to the phagocytosis.     

Transcriptional profiling of the early stages of germination in Candida albicans by real-time RT-PCR

By using real-time RT-PCR, we profiled the expression of CGR1, CaMSI3, EFG1, NRG1, and TUP1 in Candida albicans strains JCM9061 and CAI4 under several conditions, including induction of morphological transition, heat shock, and treatment with calcium inhibitors. Expression of CaMSI3 changed under these growth conditions except during heat shock. CGR1 expression increased during the early stages of hyphal growth in JCM9061, while expression was strain-dependent during heat shock. Both EFG1 and NRG1 were similarly expressed under hypha-inducing conditions and heat shock. Expression of TUP1 was slightly different from the expression of EFG1 or NRG1.     

Transcriptional profiling of the early stages of germination in Candida albicans by real-time RT-PCR

By using real-time RT-PCR, we profiled the expression of CGR1, CaMSI3, EFG1, NRG1, and TUP1 in Candida albicans strains JCM9061 and CAI4 under several conditions, including induction of morphological transition, heat shock, and treatment with calcium inhibitors. Expression of CaMSI3 changed under these growth conditions except during heat shock. CGR1 expression increased during the early stages of hyphal growth in JCM9061, while expression was strain-dependent during heat shock. Both EFG1 and NRG1 were similarly expressed under hypha-inducing conditions and heat shock. Expression of TUP1 was slightly different from the expression of EFG1 or NRG1.     

Characteristics of the ultrastructural organization of metaphase chromosomes in mouse embryos in the early cleavage stages

The structural organization of the mouse metaphase chromosomes in the early embryonic development (I-IV cleavages) was studied using serial ultrathin section. It was shown that in the first cleavage the metaphase chromosomes consist of DNP fibrils 20-25 nm in diameter, which are distributed nonuniformly along the chromosomes. It was suggested that parts of chromosomal arms formed by tightly packing DNP fibrils may correspond to the G-bands revealed by the routine Giemsa staining. In metaphase chromosomes of 8-16-cell embryos DNP fibrils form chromonema--thick threads about 90 nm in diameter. The chromonemata are evenly organized along chromosomal arms. The centromeric heterochromatin always consists of DNP fibrils tightly arranged in a block having no chromonemal level of organization. In all the cells studied chromosomes form structural contacts (associations) by their centromeric heterochromatin regions.     

Cytochemical and ultrastructural studies of Candida albicans

Ultrastructural modifications of the cell wall coat of Candida albicans during adherence to host cells were investigated using various cytochemical techniques. Attachment of the fungus to buccal epithelial cells appeared to involve spatial rearrangement of their cell wall surface. In particular adhering yeast developed a fibrogranular surface layer visualized by the periodic acid — thiocarbohydrazide silver proteinate technique (a polysaccharide detectron technique); Concanavalin A binding sites detected on their cell wall coat were highly increased. Attachment of yeasts to epithelial cells appeared mediated by fibrillar structures or polysaccharidic granules distributed on the cell wall coat. But free extra-cell wall material containing mannoproteins released from the yeast surface suggested additional mechanisms.Abbreviations Con A Concanavalin A - Man-fer mannosyl ferritin - PATAg Periodic acid-thiocarbohydrazide-silver proteinate     

Influence of staphylococcal metabolites on adhesive reactions in the system "Candida albicans-buccal epitheliocytes"

The influence of S. aureus and S. epidermitidis metabolites on the adhesive reactions in the system "C. albicans-buccal epitheliocytes" was studied. The study revealed that the treatment of C. albicans with S. aureus supernatants inhibited the adhesion of C. albicans to epitheliocytes, the degree of the inhibiting action of S. aureus supernatants in the system depending on their strain specificity. S. epidermitidis supernatants produced no adhesive effect. The irreversible decrease of the adhesive activity of C. albicans under the action of bacterial metabolites was, seemingly, the consequence of transformation of the receptor apparatus of C. albicans. At the same time S. aureus supernatants produced no essential influence on the adhesive potential and viability of buccal epitheliocytes.     

Morphofunctional characteristics of the duodenum in the early stages of experimental escherichiosis

Using the model of experimental colibacillosis in mice morphological, immunomorphological and morphometrical studies of duodenum 1 to 24 hours after inoculation were performed. Typical dynamics of cellular composition in the intestinal wall, accompanied with increased lymphoplasmacellular infiltration, and dystrophic changes in cells of submucosal and intermuscular neuroplexuses were found. The data obtained testify, that the infectious process at the acute state of experimental colibacillosis has an immune character (immediate hypersensitivity of local type), characterised by increasing in immunoglobulin-containing cells and including in this process of mast and endocrine cells.     

Antiadhesive effect of the secretion of the oral cavity in the system "Candida albicans--buccal epitheliocytes"

The influence of the oral cavity secretion on adhesive reactions in the system "C. albicans--buccal epitheliocytes" was studied. The treatment of C. albicans with natural saliva led to decrease of adhesive activity. The treatment of C. albicans with antibody absorbed saliva at different temperature conditions led to different changes of adhesion. This effect was determined by the action of temperature-dependent and temperature-independent factors, supposedly of enzymatic nature.     

Morphofunctional characteristics of spinal cord neurons in the early stages of cultivation

A study of the ultrastructural peculiarities of the spinal cord neural cells in 14 day old chick embryos at the early stages of cultivation has shown that adaptation processes are completed within the first days of explant cultivation. Further cultivation leads to the differentiation of neurons and to the recovery of their capacity of bioelectrical activity.     

Conditions and characteristics of the early stages of the sexual interaction of Pichia amethionina var. amethionina and Pichia amethionina var. pachycereana yeast cells

Pichia amethionina varieties have different sensitivity to the acidity of the medium: P. amethionina var. amethionina has the optimum pH 3 for agglutination and 5 for conjugation; P. amethionina var. pachycereana has the optimum pH 4-6 for agglutination and 6 for conjugation. The optimum temperature for the both organisms is 24 degrees C. Under the optimum conditions, P. amethionina var. amethionina has a 98% agglutination and a 28% conjugation; for P. amethionina var. pachycereana, these values are 83 and 55%, respectively. The agglutination of the two varieties does not depend on the presence of glucose. The conjugation of P. amethionina var. pachycereana does not occur in a medium without glucose while the conjugation of P. amethionina var. amethionina is reduced twofold under these conditions. Inositol, biotin and folic acid produce positive effect on the conjugation of P. amethionina var. pachycereana, but only folic acid favours the conjugation of P. amethionina var. amethionina. No differences have been found between the varieties by staining their cells and zygotes with FITC-ConA.     

Ultrastructural changes in the erythrocyte plasma membranes of chickens in the early stages of interaction with the influenza virus

Using freeze-fracture method it is shown that at the early stages of interaction with chicken erythrocytes the influenza virus induces generalized changes in the physical state of erythrocyte plasma membranes resulted from local disturbances of the cell surface in adsorption sites of virions. Ultrastructural changes seen in the membranes reach their maximum 5 minutes after infection which corresponds to the moment of maximum pinocytotic cell activity in relation to the viruses.     

Spectral characteristics and the structure of chloroplasts upon blocking the early stages of chlorophyll biosynthesis

The cotton mutant xantha (Gossypium hirsutum L.) with the blocked synthesis of 5-aminolevulinic acid in the light has been shown to accumulate chlorophyll 30 times less than the parent type. In chloroplasts of the mutant xantha, the formation of the membrane system is blocked at the earliest stages, mainly at the stage of bubbles and single short thylakoids. Only light-harvesting chlorophyll-a/b-protein complexes I and II with chlorophyll fluorescence maxima at 728 and 681 nm, respectively, are formed in plastid membranes of the mutant. It has been concluded that the genetic block of chlorophyll biosynthesis in the mutant xantha disturbs the formation and functioning of the complexes in reaction centers of PS-I and PS-II, inhibiting the development of the whole membrane system of chloroplasts at the stage of bubbles and single thylakoids.