Bacterial and yeast colonies and biofilms are well known to present populations of cells on different surfaces as a result of their duplications from one or several ones [1] - [5] . Peculiarities of colonies and biofilms are studied always of great interest; however the mechanisms for formation of intercellular contacts remain unclear.

The colonies and biofilms of microorganisms are offered to consider also as society where planktonic forms are interconnected in the various ways allowing them to get new properties of resistance in biofilms in vitro and in vivo against various stress factors of the microenvironment [6] - [9] . And only using modern high-resolution electronic microscopy of different types has opened the possibility of detailed study on structured components in bacterial cells in plankton and colonies.

Moreover, microorganisms can form biofilms attached to the surfaces of different prostheses and may play a biodegradation role [10] [11] .

In the present work, in order to install the intercellular contacts between cells in vitro in biofilms of bacteria and yeast on different surfaces including the plates, structures of zirconia have been studied by transmission and scanning electronic microscopy. In addition, some cytochemical analysis was done to make clear interpretations of walls contacts of bacteria.

Ultrastructural analysis of bacterial colonies in vitro has shown that they have fine structures which are typical for gram-negative [14] . The clarification of the structured particularities of the zone of intercellular contacts was realized with more detailed presentation of the surface structures and cell walls.

The study of the surface structures of gram-negative bacteria of E. coli (Figure 1(а)), Sh. flexnerii (Figure 2(а), Figure 3) and S. typhimurium (Figure 2(d)) in colonies has revealed the different forms of intercellular contacts. Beside enteropathogens strains of E. coli with adhesive characteristics there were fimbria, which take part both to delivering plasmid, and in fastening to the other subjects and substrates, forming three-dimensional (3D) imaging fimbrii (pilli). Stereo-metric computer analysis of transmission electronmicroscopic images was performed by the programs “Video-test, structure-5. Nanotechnology” and “Morphology” (Figure 1(b)) and of peritrichial orientation of flagellas. The sizes of the pilli varied of 100 nm to 200 nm, but diameter was ~8 nm (Figure 1(а), Figure 1(b)).

By means of comparative computer programs to manage reconstruction, stereometrical orientation of fimbria was determined to reconstruct [6] .

The other varieties for intercellular closed contacts of cell walls, crosspieces and symplasts between cells were established in the colonies of with gram-negative bacteria used. At the sites of close adhesion the fusion of cytoplasmic and outer membranes of these bacterial cells have been found to occur as shown by Bayer and Bayer [16] . The length of the bridge emergence leaves the impression of complete division of bacteria cells (Figure 2(а) and Figure 2(b)). Biofilms from colonies of bacteria and positive manner painting revealed the existence of three-dimensional surfaces bridges (see Figure 2(c)). Then, formation of S. typhimurium cells symplasts has been also visualized (see Figure 2(d)). In the last century a number of researchers distinguished R, S and L colony types in bacterial populations. Heteromorphical and L-transformations at bacteria were established both during their growth in culture and under the influence of different antibiotics and enzymes. This seems to be

likely to data reporting fusion of protoplasts and formation of symplasts for growing bacterial cells and under the influence of antibiotics during L-transformation in culture of Salmonella as suggested [17] [18] . These have practical interest, giving a possibility to use them for crossbreeding and constructions of strains with useful characteristics.

The contacts between gram-negative bacterial cells were also found with the help electron cytochemistry reaction. Probably mucopolysaccharid layers of a microcapsule play important cytoprotective role in those contacts between bacteria [19] [20] . Localization of mucopolisacharides positive reaction by cytochemistry was considered as establishing electrondens layer on outer membrane of Sh. flexnerii was obtained (see Figure 3).

Capsule-like layer has been visualized for gram-negative S. typhi under interaction with different eukaryotic cells, for instance macrophages. Interestingly, duplication and formation of micro-colonies in phagosomas of eukaryotic cells were installed at electron microscopic study of interactions of S. typhi with peritoneal macrophages [21] . It is likely that intercellular contacts were formed depending on the degree of hydrophobic cellular surface of bacteria and on their antiopsoninecy to protective action [22] .

Besides, together with sinergetic interrelations between studied and other type of bacteria in mixed culture of S. enterica and O. oenii there are the antagonistic interactions (Figure 4). The latters were observed with different bacteria resulted as structural changes in Salmonella cells walls. These findings can point out changing interrelations in mixed cultures. A change in the nature and forms of the relations between bacteria in mixed culture confirms the possibility of the manifestation of new functions in their community in nature. This finding might be applied for prevention and treatment in intestine microbiota of different strepto-staphylococcal infections [23] [24] .

SEM of intact yeast cultures C. guilliermondii NP-4 has shown typical structural images for yeasts colonies (Figure 5(а)); the clarification of the structured particularities of the different forms of intercellular contacts zones is cell wall and is fastening to the inorganic plate substrate of zirconia. Measurement of C. guilliermondii sizes by means of the program “Morphology” has shown the following: diameter was 1.15 - 2.71 μm, length― 3.22 μm and buds―0.318 μm. In addition, adhesion of yeast on the plate surface with porous of zirconia and multiform division of cells and multitude of buds were established. SEM analysis of yeasts colonies showed that the clarification of the structured particularities of the different forms of intercellular contacts zones is with cell wall and in fastening to the plate substrate of zirconia (Figure 5(а) and Figure 5(b)).

Ultrastructural analysis of bacterial colonies and biofilms has shown that they have surface structures and cell

walls which are typically Gram-negative [14] . In the last century a number of researchers distinguished R, S and L colony types in bacterial populations. Heteromorphic and L-transformations at bacteria were established both during their growth in culture and under the influence of different antibiotics and enzymes. This seems to be likely to data reporting fusion of protoplasts and formation of symplasts for growing bacterial cells and under the influence of antibiotics during L-transformation in culture of Salmonella [17] [18] . These have practical interest, giving a possibility to use them for crossbreeding and constructions of strains with useful characteristics.

Capsule-like layer has been visualized for gram-negative S. typhi under interaction with different eukaryotic cells, for instance macrophages. Interestingly, duplication and formation of micro-colonies in phagosomas of eukaryotic cells were installed at electron microscopic study of interactions of S. typhi with peritoneal macrophages [21] . It is likely that intercellular contacts were formed depending on the degree of hydrophobic cellular surface of bacteria and on their antiopsoninecy to protective action [22] . Adhesion and immobilization of bacteria on porous ceramic surfaces create prerequisites for the prevention of microbial contamination with prothesisation [25] and, on the other hand, for wastewater treatment [26] [27] .

TEM, SEM and cytochemistry electron microscopy of bacteria and yeast forming biofilms have clearly visualized the intercellular contacts caused by the presence of fimbrias, flagellas, polysaccharides of microcapsules, and intracytoplasmic polyphosphates. These structures promote Bayer-like dense contacts, membranes fusion, crosspieces of cell walls and, at the last, merge protoplasts with formation of simplasts. Moreover, the results of this study indicate that in colonies bacterial cells are not completely isolated: their interaction leads to the formation of cooperative cell systems.

The authors express their thanks to Drs. G. Gasparyan and A. Priyatkin for helpful advice and valuable comments. This work was supported in part by Ministry of Education and Science of the Republic of Armenia (basic support).

The authors have no conflict of interest.

Karlen Hovnanyan,Seda Marutyan,Astghik Pepoyan,Liparit Navasardyan,Armen Trchounian, (2015) Transmission and Scanning Electron Microscopy of Contacts between Bacterial and Yeast Cells in Biofilms on Different Surfaces. Open Access Library Journal,02,1-10. doi: 10.4236/oalib.1101492