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L N Kats

Publications and source records attributed to L N Kats.

At least 37 records · Page 2Linked to original sources
PubMed1978

[Structural study of Mycoplasma by a scanning electron microscopy method].

Scanning electron microscopy was applied to the study of Mycoplasma arthritidis, Myc. gallisepticum, and Acholeplasma laidlawii. Small spherical elements (0.3--0.5 micrometer) formed a reticular "framework" of the colonies in which larger (1--1.5 micrometer) spheroid or irregular-shaped cells (in case of Myc. gallisepticum) and also rod-shaped (1--3 micrometer), filamentous (3--5 micrometer) forms and "large bodies" (5 x 3--8 x 3.5 micrometer) were located. Apparently the latter represented conglomerates of adherent spheroid elements that resembled somewhat "large bodies" of L-forms. Small spheroid buds were revealed on the surface of all the elements.

L Forms↗
PubMed1977

[Study of streptococcal L forms in the scanning electron microscope. II. Dynamics of the development of structural elements of L colonies at different stages of growth].

The method of scanning electron microscopy showed that the L-colonies of streptococcus were formed by the spherical structures 0.1--1.5 micronm in diameter, elements of polygonal shape (large bodies) 10--30 micronm in size, filamentous structures 01--7 micronm in diameter and structureless matrix. A regular replacement of one form by another was observed in the process of the L-colonies development. Thus, the spherical elements appeared in the lag-phase, and polygonal elements were found mostly at the initial stages of the L-colonies formation; as to the filamentous structures -- they were present at all the developmental stages, but their diameter increased, and their structure and number changed at different growth phases. The spherical elements of the L-colonies formed evenly both on the structureless depth matrix of the colonies, on the filamentous structures in the form of buds on the "large bodies", and the disintegration of the latter. The role of the filamentous structures in the development of the L-colonies is discussed.

L Forms↗
PubMed1977

[Morphologic characteristics of the large bodies in cultures of the L-forms of bacteria according to scanning electron microscope studies].

Large bodies appear at the time of protoplast and spheroplast formation and are revealed at all the L-transformation stages and at the initial stage of reversion. They can be represented both by a single giant cell and by a conglomerate of different cells connected with one another. They are not only spheroid, but can be of the most varied shape, and structurally they are connected with other L-colony elements: filamentous structures, spheroid cells, elementary bodies and the so-called acellular material. At the early L-transformation stage the large bodies probably appear as a result of coalescence of lysed cells and represent polygenome formations. Elementary bodies and spheroid cells form within the large bodies and on their surface at the late stage of L-transformation. In case of reversion bacterial cells form from them.

L Forms↗
PubMed1977

[Biological properties and ultrastructure of brucellae during L-transformation and reversion].

There was shown a difference in the biological properties and the ultrastructure of two strains of brucellae, spheroplasts obtained from them under the action of penicillin, L-form and revertants obtained from the L-form. Spheroplasts formation was characterized by a change of brucellae into R-form and some virulence reduction. The cells had an outer and a cytoplasmic membranes, and usually lost their capacity to binary division. L-forms were obtained during the 9th and the 35th passage on a medium with penicillin; their formation was accompanied by the change in serological properties of the culture and significant reduction of the virulence; the cells were characterized by a marked polymorphism and the capacity to budding; they had 2 membranes on the cell surface and an intensively developed system of intracytoplasmic membranes. The revertants formed on the medium without penicillin during the 16th-30th passage or spontaneously on the medium with penicillin. They differed from the initial strains of brucella culture by a marked increase in penicillin-resistance, by the changes in serological properties, and also by polymorphism of cells, capable, however, of binary division.

Brucella abortus↗
PubMed1977

[Morphologic characteristics of spheroid elements in a culture of bacterial L-forms according to scanning electron microscopy findings].

The authors studied stable L-cultures of Proteus valgaris, Bac. subtillis, Staphylococcus aureus, Streptococcus pyogenes of group A, and also unstable cultures of the L-forms of Proteus vulgaris and Proteus vulgaris culture at the stage of spheroplasts. Spheroid cells proved to appear at the stage of spheroplasts, prevailed at the log phase in stable and unstable L-cultures, but were less frequent at the stationary phase. Cross section of L-colonies showed that they were located at the surface. The size of spheroid elements was from 1 to 5 micron; their surface was smooth or slightly wrinkled with numerous protrusions and individual sockets. The spheroid cells were distributed in the colonies freely, in clusters, or were connected to one another by anastomosis. Several methods of reproduction of spheroid cells are described, including equal and unequal binary fission, budding, and formation of elementary bodies within the cell. Morphological connection of spheroid cells with large bodies, filamentous structures and structureless matrix of the L-colony apparently pointed to their origin from the corresponding elements of the L-cultures.

Bacillus subtilis↗
PubMed1977

[Certain data on the protoplast ultrastructure].

A study was made of the structure of Bac. subtilis and Listeria monocytogenes protoplasts by the method of scanning electron microscopy. The mechanism of protoplast formation in Gram-positive bacteria and in spheroplasts of Gram-negative bacteria proved to differ. A loss of the rigid form of the cell, round protrusions on cell surface, and an escape of the cytoplasm through the ruptured cell wall in some one place was noted in case of protoplasts. Individual cells can coalesce with one another with the formation of shapeless masses. The formation of small spheroid bodies by budding, and also a division of protoplasts by constriction was described.

Bacillus subtilis↗
PubMed1976

[L-forms of streptococcus in the scanning electron microscope. 1. Structural elements of L-colonies].

Broth culture of stable L-forms of beta-hemolytic streptococcus, group A, was studied in the log phase. Internal portion of the centrifugate constituting the matrix of the L-population represented a structureless mass in which the borders of individual cells were not always distinct; the cells adhered to one another and were irregular in shape. The described morphological picture corresponded to the internal part of the L-colonies from the semifluid medium in observation under phase and scanning microscope. A more peripheral portion of the centrifugate was formed by the spherical cells, about 2 mum in diameter; penetrating holes or crater-like invaginates and also small spherical structures, about 0.5 mum in diameter were often revealed on these cells. Filamentous structures, up to 200 mum in length which protruded far into the surrounding environment served as the most peripheral elements. Analogous structure were described in the L-colonies examined by phase contrast microscopy. The data of transmission and scanning microscopy are compared.

L Forms↗
PubMed1976

[A study of Proteus L forms during reversion by means of electron microscopy and ultrathin sections].

The method of scanning electron microscopy was applied to the study of the Proteus L-forms which reversed directly on the millipore filters. It appeared that reversion was accompanied by elongation of the cell, piriform cells forming as the result. Filamentous cells segmented into short fragments and large bodies with a spongy surface structure with numerous ruptures were also revealed in the reversing culture. The method of ultrathin sections showed the other membrane in many cells to be fragile and readily twisting forming vesicles collecting into chains. As supposed, this is connected with degenerative changes involving the outer membrane of the paternal L-forms at the early reversion periods. An interrupted structure of the outer membrane was also demonstrated in many cells. It is supposed that in this case a synthesis of the outer membrane de novo at the later stages of reversion is dealt with. Phenomenon of "extrusion" of the multilayer structures into the periplasmic space, characteristic of spheroplasts, is described. A marked similarity of the morphological picture of reversion and at the initial stages of L-transformation, i.e. of the processes representing a looking glass reflection of one another, is described.

Cell Membrane↗
PubMed1976

[In vitro obtaining stable L forms of group A beta-hemolytic streptococci type 1 and 12].

Stable L-forms of hemolytic streptococcus of group A of the 1st and 12th types were obtained in vitro under the effect of penicillin. L-form strains were passaged over 40 times and failed to reverse to the initial. Stability of the obtained L-cultures of the 1st and 12th types was confirmed by electron microscopy which showed the absence of cell wall in them. Morphology of the colonies on hard nutrient medium showed some difference in the L-form strains of the 1st and 12th type. Phage contrast microscopy demonstrated in the culture of the 12th type a relatively greater number of granular structures; as to the L-form cultures of the 1st type, it was mainly represented by the globular elements. Submicroscopic characteristic of the L-form of streptococcus was revealed on the ultra-thin sections of both L-form strains.

Culture Media↗
PubMed1976

[Ultrastructure of L forms. Report 5. localization of dehydrogenase activity in L form cells].

A study was made of deposition of diformazan TNBT and TCNBT in the presence of succinate and without it in stable L-forms of Str. pyogenes group A, St. aureus and L. monocytogenes. Diformazan proved to deposit on the cytoplasmic membrane, in the lamellar mesosomes and myelin-like structures and also on individual intracellulor membranes not forming special membrane organoids. Diformazan was localized on the membranes mostly asymmetrically, on the cytoplasmic membrane-on its internal side, and on the ring-like intracellulor membranes- externally. Localization of diformazan on the ring-like membranes is atributed to the fact that ring-like membranous structures in the L-forms formed as a result of invagination of the cytoplasmic membrane in the same way as bacterial mesosomes. Since L-form cells could not be released of endogenous substrates by the methods elaborated for bacteria, cytological data did not permit to ascertain dehydrogenases, responsible for asymmetrical localization of diformazan on the L-form membranes. On the basis of these data one can judge only the sum total activity of dehydrogenases in different membranes.

Formazans↗
PubMed1975

[The ultrastructure of L-forms. III. The L-forms of S. typhi and Pr. vulgaris].

A marked polymorphism was revealed in the colonies of 5--7 day L-forms of S. typhi and Pr. vulgaris: among different types of the cells there prevailed spherical or oval forms with a distinct nucleoid. Three-layer cytoplasmic membranes--the site of formazan TNBT deposition in the reaction for succinic dehydrogenase--were detected on the greater part of the cell surface. Sometimes there were revealed on the surface of the membrane residues of the cell wall in the form of structureless material of low electron density or pieces of external membrane. Myelin-like structures, mesosomes of ring or lamellar structure and two-contour vesicles located directly in the cytoplasm were found in the cytoplasm. L-form cells displayed binary fission or reproduced by budding; in the latter case there formed elementary bodies surrounded by a three-layer membrane, not infrequently with a visible nucleoid and structures resembling mesosomes of the lamellar type.

Cell Division↗
PubMed1975

[Ultrastructure of L forms. IV. L forms of nonagglutinating vibrios].

A study was made of the ultrastructure of stable L-forms of Nag vibrios aged 24 hours. Cells of all types of the L-forms had cytoplasmic membranes, and a three-layered structure, which was found not everywhere. Externally of the cytoplasmic membrane, in some areas of the individual cells there were revealed a plastic layer of cell wall and a basal membrane. However, in difference to bacterial forms of the vibryos, rigidity of the cell wall was disturbed, and the links between the cell wall and the cytoplasmic membrane were indetectable. There were regularly revealed lamellar of myelin-like membranous structures in the cytoplasm, which did not occur in bacterial forms, and also lamellar mesosomes. The latter were found in the sites of cell division. Viability of small bodies as the minimal reproductive forms of the L-cultures is confirmed by the presence in them of a nucleoid and of the binary division.

Basement Membrane↗
PubMed1975

[Ultrastructure of L-forms. II. L-forms of Listeria monocytogenes].

A study was made of ultrathin sections of the stable l-forms of listeria obtained under the action of penicillin in meat-peptone-liver broth. A marked cellular polymorphism was found in the L-form culture: within the same colony cells differed in size, shape and fine structure. It is supposed that polymorphism could be partially explained by a different plasticity and premeability of cytoplasmic membrane in different types of cells of the same L-colony. The three-layer structure of the membrane does not always display the same distinctness in various L-colony cells and also in different areas of the cell surface. Structureless material of low electron density, possibly a defective murein or its precursor, was revealed on the membrane surface. Electrondense inclusion bodies, mesosomes of ring-shaped or more complicated structure and two-contour vesicles were found in the cytoplasm. The cells multiplied by budding, by binary and anomalies division participation of mesosomes in this process was not proved by the L-forms.

Cell Wall↗