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Results for “small rod morphology”

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At least 19 recordsLinked to original sources

PubMed2026

The Absence of E. coli Nucleoid-Associated Protein FIS at Low Temperature Leads to an Adaptation Response That Causes a Shift Towards Genome Compaction in Small Rods.

In contrast to the rod shape at 37°C, the morphology of Escherichia coli cells at temperatures just above the minimum temperature of growth is small rods. A study was initiated to determine the requirement of nucleoid-associated protein FIS for growth and genome compaction in the small rods at low temperature. Growth and nucleoid staining analyses revealed that the fis null mutant displayed decreased growth and initially formed filaments containing decondensed nucleoids at 12°C, indicating that FIS facilitates production of small rods with condensed nucleoids at low temperature. However, characterized by biphasic growth at low temperature, the fis null mutant exhibited increased growth, cell division, and nucleoid condensation following an acclimation phase. Therefore, the absence of FIS with nucleoid decondensation leads to an adaptation mechanism, termed FIS Null Adaptation Response, that causes a shift towards nucleoid condensation resulting in genome compaction in small rods. Furthermore, overproduction of the HsIVU protease suppressed the cold-sensitive phenotypes of the fis null mutant indicating that degradation of a natural substrate of the protease alleviates the requirement of FIS at low temperature. In addition, null mutations of genes encoding natural substrates of HsIVU (exoribonuclease RNAse R, and cell division inhibitor SulA) were identified as extragenic suppressors of the fis null mutation.

Escherichia coli↗

PubMed1977

Immunochemistry of Yersinia enterocolitica O3 grown at different temperatures.

Comparative agglutinations of homogeneous stable suspensions prepared with Yersinia enterocolitica growth at 37 degrees C and at 25 degrees C were performed with anti-sera prepared in rabbits with the bacteria grown at both these temperatures. Sera prepared with live Y. enterocolitica grown at 37 degrees C agglutinated both suspensions at a much lower titre than the sera prepared with formaldehyde-treated bacteria is grown at 25 degrees C. All the sera in which strongly precipitating antibodies were induced reacted, in agar-gel, against native and heated proteins. The small amounts of antipolysaccharides induced in all the sera reacted only in the ring test against the bacterial polysaccharides. The absorption of the sera prepared with live Y. enterocolitica grown at 37 degrees C, with antigens synthesized at 25 degrees C did not remove all the homologous antibodies; apparently, some determinants are specific for the bacteria grown at 37 degrees C. Morphological changes of the small rods to elongated bacilli and filamentous forms were observed in most cultures of the Y. enterocolitica grown at 37 degrees C; these changes coincided with a low yield of proteins and point to an inhibitory effect of the 37 degrees C temperature.

Agglutination Tests↗

PubMed1976

Evidences for complex formation between polymyxin B and lipopolysaccharides from Serratia marcescens.

In vitro and in vivo complex formations of polymyxin B and lipopolysaccharides (LPS) from resistant and sensitive cells of Serratia marcescens were studied by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and electron microscopy. In vitro treatment of LPS from resistant cells with polymyxin B gave two populations of spherical complexes of differnt molecular weights as determined electrophoretically. Similar treatment of LPS from sensitive cells resulted in dissociation of the LPS-protein and subsequent complexing with the LPS moiety into stable spheres. In vivo treatment of resistant cells with polymyxin B resulted in LPS-polymyxin B complexes which were comparatively smaller and existed in two morphological forms; spheres and linear ribbons. LPS from the sensitive cells were degraded extensively into small rods and an amorphous mass by the in vivo polymyxin B treatment. In both systems, the electrophoretic results consistently matched the electron microscopic evidences for complex formation of LPS with polymyxin B. It is suggested that the disruptive effects of polymyxin B on LPS in the outer membrane of S. marcescens may be the explanation for the change in permeability barrier in the resistant cells and disorganization of the outer membrane and subsequent death in the sensitive cells. Furthermore, the ability of the LPS to complex with the polymyxin B molecules in resistant cells may be the basis of their resistance to the antibiotic.

Bacterial Proteins↗

PubMed1975

[Morphological and cytofluorometric study of the giant cells of the trophoblast of the common vole].

The primary and secondary giant cells of trophoblast in placenta Microtus arvalis were studied. The giant polyploid nuclei are formed in result of series of successively proceeding endomitotic polyploidization of chromosomes. Two stages of endomitosis are described: endointerphase with the uniform net of thin chromatin threads and the stage when small round or rod-shaped paired chromosomes gather mostly under the nuclear membrane. Great number of round, oval, and complex-shaped nucleoli may be seen in nuclei during both stages of endomitosis, the number growing during polyploidization. The morphology of the chromosome-nucleolar apparatus involves peculiarities of the polyploidization mechanism in placenta Microtus arvalis trophoblast. Endomitosis occurs both in low and high-polyploid nuclei. Cytofluorometric determination of the DNA amount in nuclei polyploid nature. The degree of polyploidy of the trophoblast giant cells nuclei during terminal differentiation of placenta corresponds to 128c-512c, and some nuclei contain the DNA amount corresponding to 1024 and 2048 chromosomal sets. The cause of origin of the polyploid cells in trophoblast of rodents placenta is discussed.

Animals↗

PubMedDate not supplied

[Electron microscopic study of the pond microflora of the Amu-Dar'ia River delta].

Bacterial forms were studied by electron microscopy in weakly saline lakes of the mesotrophic type in the Amu Darya delta; these forms differed in the character of water nutrition, certain physico-chemical and biological properties. The main population in the lakes represented by Vibrio and rods among which many small forms (0.3--0.5 mu) were found. Long filamentous forms were often encountered. A considerable number of organisms possessed prosthecae, fimbria and various protrustions. Budding bacteria were also detected. Microorganisms with peculiar morphology were most abundant in such places where the total incidence of bacteria was 1x10(6) per litre while water transparency was low.

Bacteria↗

PubMed1979

An ultrastructural demonstration of the agent of Legionnaires' disease in the human lung.

The authors have provided ultrastructural demonstration from human material of a small rod shaped organism that represents the causative agent of Legionnaires' disease. The organisms are found mainly in intracytoplasmic vacuoles of alveolar cells. They have a thin outer cell wall and a more delicate plasma membrane. On the basis of morphology, arguments are presented to classify these unusual organisms as rickettsia-like.

Bacteria↗

PubMed1978

Ultrastructural cytochemical demonstration of peroxidase-positive monocyte granules: an additional method for studying the origin of mononuclear cells in encephalitic lesions.

Unlike lymphocytes, blood monocytes possess in their cytoplasm peroxidase-positive (azurophil) granules (ppg) which largely correspond to the homonymous organelles of neutrophil granulocytes. We tested whether ppg, demonstrated cytochemically at the submicroscopic level, could serve as markers of monocyte-derived reactive mononuclear cells in encephalitic lesions. Samples of cerebrocortical tissue from adult albino mice with experimental yellow fever virus encephalitis were incubated in a medium containing diaminobenzidine and H2O2 for localization of peroxidatic activity. Mononuclear cells exhibiting ppg were found (1) in the lumen of brain venules, (2) in different stages of migration through the walls of such vessels, (3) in perivascular areas, (4) in the glioneuropil, either loosely scattered or forming small clusters, (5) in a satellite position to neurons, and (6) in leptomeningitic inflitrates. Several mononuclear elements harboring ppg had assumed an elongated, rod cell-like outline. Amongst the peroxidase-negative mononuclears were fully developed brain macrophages and elements showing morphologic features characteristic of activated lymphocytes. Most mononuclear cells without ppg resembled the peroxidase-reactive ones. The results of this study provide direct evidence in favor of a monocytic origin of, at least, numerous reactive mononuclear elements in encephalitic lesions. The approach followed in the present study is not suitable for quantitative investigations of the histogenesis of mononuclear cells responding to brain injuries, since emigrated blood monocytes rapidly lose their ppg, particularly, when they display enhanced phagocytic activity.

Animals↗

PubMed1978

Photoreceptors and oil droplet colors in the red area of the pigeon retina.

Six types of photoreceptors in the red area (dorso-temporal quadrant) of the pigeon retina are identified using Golgi impregnation, light microscopy and electron microscopy. Golgi impregnation is used to categorize the receptors into morphological types. Examination of oil droplets in the inner segments of cones in fresh, unfixed tissue shows five different types which can be characterized by color, size and stratification. Therefore, in sections through the length of the receptors examined by electron microscopy, the oil droplets contained in the inner segments of the cones can be identified as to their color by their characteristics (i.e., size and stratification), and the groups of receptors thus classified, further characterized as to the morphology of their terminals. Rods have no oil droplets in their inner segments, and their synaptic terminals are located in the outermost stratum of the outer plexiform layer OPL). Principal members of double cones have yellow oil droplets in their inner segments, while accessory members contain small colorless oil droplets. The synaptic terminals of double cones are located in the same (outermost) stratum of the OPL as rod synaptic terminals. Two types of single, straight cones house either red or orange oil droplets and terminate in the intermediate stratum of the OPL. Oblique single cones with yellow-green oil droplets in their inner segments contribute synaptic terminals to the innermost stratum of the OPL.

Animals↗

PubMed1975

Ultrastructure of quiescent oocytes of Cebus albifrons.

Quiescent oocytes of the monkey Cebus albifrons were examined with the electron microscope. In many respects the ultrastructure of these cells was similar to that of other mammalian species. Elongate and oval mitochondria, lamellar Golgi complexes, small profiles of smooth endoplasmic reticulum, and vacuolar organelles were randomly distributed around a round nucleus which usually contained a nucleolus and clumps of heterochromatin. Among the unusual morphological characteristics of these oocytes are 'membranous aggregates', membrane-bound organelles containing a complex of convoluted membranes, some very dense rod-like structures and a droplet of moderate density which resembles lipid. A similar droplet is frequently found in mitochondria. Rough endoplasmic reticulum is abundant in many of these oocytes, forming parallel arrays and concentric rings around the nucleus. Folded membrane complexes, apparent elaborations of smooth endoplasmic reticulum, are frequently found in the cytoplasm in continuity with cisternae of smooth and rough endoplasmic reticulum and associated with vesicles which often contain flocculent material. The morphology of Cebus oocytes suggests a greater rate of steroid and protein synthesis, transport, and storage than is usually indicated by the ultrastructure of other mammalian oocytes.

Animals↗

PubMed1977

[Dissolution of polyhedra of the nuclear polyhedrosis virus of the leatherjacket Tipula paludosa MEIG. Ultrastructural study of the virion (author's transl)].

The inclusion bodies of the nuclear polyhedrosis virus of T. paludosa MEIG. were purified by sucrose density gradients, their morphology described using scanning electron microscopy, and the conditions for their solubilization investigated. These inclusions known to be unusually resistant to dissolution, were successfully dissolved in conditions maintaining the integrety of the virus particles by using a 0.125 M sodium thioglycolate + 0.125 M sodium bicarbonate solution, pH 10.5. The virions extracted from the inclusions were purified by sucrose density gradients and their fine structure studied in electron microscopy. In PTA-stained preparations the virion is rod-shaped measuring 230--240 nm in length and 100 to 110 nm in diameter. It consists of an inner nucleocapsid surrounded by a loose envelope. Partially degraded virions reveal small subunits arranged in a regular helix (pitch of approximately 40 A) at the surface fo the capsid. These subunits likely represent the virus capsomers. A flexuous ropelike structure protruding at one end of the capsid is sometimes observed in partially degraded virions stained with uranyl acetate. In thin sections of infected hemocytes, the virions occluded on polyhedra or free in the nucleoplasm exhibit the same morphology although their diameter does not exceed 80--85 nm. The muclear polyhedrosis virus of T. paludosa meets all the criteria for incorporation into the Family Baculoviridae.

Animals↗

PubMed1979

Morphogenesis of rod cells in the retina of the albino rat: a scanning electron microscopic study.

This study presents scanning electron microscopic (SEM) observations of topographical changes that occur during morphogenesis of rod cells in the albino rat. Correlative transmission electron microscopy (TEM) was also utilized. Albino rats ranging in age from birth to three weeks were used for the study. Tissues were prepared by conventional methods for SEM and TEM. At birth, numerous irregularly arranged inner segments extend from the external surface of the sensory retina. They are spherical, smooth surfaced and possess a randomly oriented cilium. The internal morphology of these immature inner segments is comparable to that observed in other vertebrate species. Statistical analysis reveals a rapid increse in the number of rod cells during the first week. This period is characterized by the elongation of inner segments and their associated cilia. Microvilli project from the apices of Müller cells, but not from adjacent inner segments. By day 5, cilia occasionally display small bulbous outer segments. They are more numerous by day 8 and are usually eccentrically positioned at the tips of cilia. By day 11, outer segments are abundant and frequently obscure from view the underlying inner segments and associated cilia. Elongated cylindrical outer segments are present within the posterior retina at the end of the second week. However, rod cell morphogenesis lags in the peripheral retina. Topographical variations between developing photoreceptor cells in mammalian and non-mammalian retinas are discussed.

Aging↗

PubMed1975

Morphological and functional identifications of catfish retinal neurons. I. Classical morphology.

The morphology of the catfish horizontal cells is comparable to that in other fish retinas. The external horizontal cells contact cone receptors and are stellate in shape; the intermediate horizontal cells are even more so and contact rod receptors. The internal horizontal cells constitute the most proximal layer of the inner nuclear layer and may possibly be, in reality, extended processes from the other two horizontal cell types. Bipolar cells resemble those in other teleost retinas: the size and shape of their dendritic tree encompass a continuous spectrum ranging from what is known as the small to the large bipolar cells. The accepted definition of amacrine cells is sufficiently vague to justify our originating a more descriptive and less inferential name for the (axonless) neurons in the inner nuclear layer which radiate processes throughout the inner synaptic layer. These starbust and spaghetti cells vary considerably in the character and extent of their dendritic spread, but correlates exist in other vertebrate retinas. Ganglion cells are found not only in the classical ganglion layer but displaced into the inner nuclear layer as well. Several types can be distinguished on the basis of cell geometry and by the properties of their dendritic tree. Not all of the categorization corresponds with previous descriptions; our findings suggest that some reorganization may be necessary in the accepted classification of cells in the proximal areas of the vertebrate retina. A subtle yet remarkable pattern underlies the entire structure of the catfish retina; there exists a definite gradient of size within a particular class of cells, and of configuration among the subclasses of a specific cell type. It remains to be seen if these morphological spectra bear any functional consequences. The fact that the structure of the catfish retina most closely resembles those of other phylogenetically ancient animals, such as the skate and the dogfish shark, testifies to its primitive organization; morphological and functional mechanisms discernible in this simple system may, therefore, be applicable to the retinas of higher ordered vertebrates.

Animals↗

PubMed1975

[New morphologic principles of the physiology of smell and taste].

New results as revealed by scanning and transmission electron microscopy have given us further knowledge about the structure of the olfactory region of vertebrates. With comparative studies we are now able to discuss the functional relationship of this region. In all vertebrates the olfactory cell is a primary sensory cell. The apical segment of the olfactory cell with its olfactory vesicle is involved in the formation of the olfactory border. As a rule of the receptor possesses cilia or cilia-like processes. These are absent in the olfactory receptor of the shark, the microvillus receptor of the fish and the olfactory cell of Jabonsons organ of amphibians, reptiles and mammals. The odorous substances in the fish are brought to the receptor membrane by the water flow. In air breathing vertebrates a terminal film is present. This film is a product of secretion from the Bowmans glands. Gasous odorous substances must first be dissolved in the terminal film and penetrate it before reaching the receptor membrane. The cilia-like olfactory process of the fish in the proximal segment is not essentially different from the kinocilia of the supporting cell, except that they are shorter. In contrast the olfactory cell of air-breathing vertebrates form cilia-like processes with a short cilia-like proximal segment and a long and very thin distal end piece. In the amphibians and sauropsidians the end pieces can have a length of up to 150 mu and up to 80 mu in mammals. The olfactory vesicles with its processes undergo continuous regeneration. The olfactory epithelium of man show the same structural formation as observed in other mammals. Regressive changes in the adult can lead to a reduction in the number of sensory cells and also to a flattening of the epithelium. Morphological criteria for regenerative processes in the sensory cell structures are present. A specialized olfactory cell type has been found in some teleosts. This cell is characterized by a small pit below the olfactory border in which the cilia of the olfactory cell are redrawn. There is some evidence that this olfactory cell type may be compared with the olfactory cells in the parafollicular tubes of lamprey. The so called rod-shaped receptor in the olfactory mucosa of fishes has no axon and is therefore no olfactory cell. The same kind of cell is also present in the olfactory mucosa of air-breathing animals. We classify this cell as brush cell.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1979

Comparative studies of penicillin-binding proteins in Pseudomonas aeruginosa and Escherichia coli.

Penicillin-binding proteins in Pseudomonas aeruginosa were compared with those of Escherichia coli. These in P. aeruginosa were found exclusively in the cytoplasmic membrane fraction (fraction soluble in sodium N-lauroyl sarcosinate). Sodium dodecyl sulfate/acrylamide gel electrophoresis of the proteins bound to [14C]penicillin G resulted in the separation of six major bands and several minor bands. The proteins in these bands are referred to as proteins 1A, 1B, 2, 3, 4 and 5 in order of increasing electrophoretical mobility. The electrophoretic mobilities and other properties of penicillin-binding proteins in P. aeruginosa and E. coli were compared and correlated. Fundamentally they seem to be very similar in the two bacteria, but proteins 1A and 1B in P. aeruginosa seem to correspond respectively to proteins 1B and 1A in E. coli, and protein 6 seems to be missing or present in only small amount in P. aeruginosa. In addition, the affinities of currently developed beta-lactam antibiotics to each protein of P. aeruginosa and E. coli were examined in relation to the morphological changes of the cells induced by these antibiotics and their antibacterial potencies. Mecillinam showed high affinity to only protein 2 in both P. aeruginosa and E. coli. At a minimal inhibitory concentration, it converted cells of both P. aeruginosa and E. coli from rods to spherical cells, although its minimal inhibitory concentration was much higher for P. aeruginosa than for E. coli.

Binding, Competitive↗

PubMed1978

Antibacterial functions of macrophages in experimental protein-calorie malnutrition. I. Description of the model, morphologic observations, and macrophage surface IgG receptors.

An experimental protein-calorie malnutrition was produced in weanling Sprague-Dawley rats. The model resembles human malnutrition with respect to weight loss, inanition, angular stomatitis, anemia, lymphopenia, hypoproteinemia with hypoalbuminemia, and marked thymic involution. In addition, systemic invasion by gram-negative rods was documented. However, no edema was produced, and animals did not survive for longer than six weeks on the protein-deficient diet. One percent glycogen was found to be a satisfactory nonprotein stimulus for induction of a peritoneal exudate consisting primarily of young macrophages. Electron microscopy showed that morphologic events of phagocytosis and degranulation proceeded normally in macrophages from protein-deficient animals. In addition, cell surface receptors for IgG were preserved under these experimental conditions. These data indicate that weanling rats may be employed as a small animal model for servere, fulminant protein-calorie malnutrition in humans.

Animals↗

PubMed1975

[Congenital desproportion of various types of muscle fiber, with relative small size of type I fibers. Morphological documents on muscle biopsies in 3 members of the same family].

In two sisters with a neo-natal hypotonia, muscle biopsies demonstrated as main pathological feature a disproportion in size between the two types of muscle fibers defined according to their myofibrillar ATPase activity. Type I fiber mean diameter was at the lower limit of the normal values, and type II fibers were larger than normal. Their father's biopsy also showed an abnormal smallness of the type I fibers, with a bimodal distribution. By electron microscopy, the small type I fibers did not reveal any significant abnormality in children's biopsies. In father's biopsy, there was an abnormal degree of filamentary interchange between contiguous myofibrils and a few stacks of rods in the type I fibers. These three cases demonstrate the familiar character of the disorder. The relationship of this new entity with the other congenital myopathies is controversial, as a similar congenital fiber type disproportion, has been found in association with different ultrastructural changes. Several data favour an insufficient development of the type I fibers rather than an atrophying process. The mechanism of this "hypotrophy" remains unknown.

Adenosine Triphosphatases↗

PubMed1979

Ultrastructure and cytokinetics of leukemic myeloblasts containing giant granules.

Leukemic myeloblasts containing abnormal granules were studied with ultrastructural, cytochemical, and thymidine labeling techniques to evaluate defects in granulogenesis and proliferation. Giant granules (1 to 3 micron in diameter) and Auer rods were observed in leukemic cells from two patients, and only rarely were both abnormal granule types observed in the same cell. The lysosomal origin of these abnormal granules was demonstrated by their content of peroxidase, esterase, and anionic glycoconjugates. Fusion of small dense granules (less than 0.2 micron in diameter) appeared to be increased in cells containing Auer rods and/or giant granules, but fusion of intact primary granules (0.2 to 0.4 micron in diameter) and sequestration of cytoplasmic contents were observed only in giant granules and not in Auer rods. Although the small granules that fused to form giant granules and Auer rods appeared similar, there was no evidence for transformation of giant granules into Auer rods. In one patient, cells with abnormal granules could easily be distinguished from the larger population of cells that lacked abnormal granules. The perturbation of these two distinct populations by chemotherapy was evaluated with thymidine labeling experiments. A high percentage (2- or 3-fold greater) of the abnormally granulated myeloblasts incorporated tritiated thymidine when compared to myeloblasts without abnormal granules in the same specimen. This difference could have resulted from an underlying metabolic defect which affected both granulogenesis and cell division. These results demonstrate that the formation of giant granules in leukemic cells is morphologically similar to that observed in the Chediak-Higashi syndrome and that leukemic cells with abnormal granules may differ cytokinetically from uninvolved leukemic cells.

Cell Division↗

PubMed1976

Extraocular muscles: light microscopy and ultrastructural features.

Thirty extraocular muscles (EOM) from 20 patients were evaluated by light microscopy (LM), electron microscopy (EM), and enzyme histochemistry (EZH). Twenty-one EOM were obtained from 13 patients with strabismus, 9 EOM from 4 patients undergoing eye surgery for other reasons and from 3 autopsy cases. One mum thick sections revealed marked variation in muscle fibre shape and size and in myofibrillar structure; also noted were small, hypertrophied, whorled, and ringbinden fibres. Dense and granular material in the central portion of some fibres and sarcomere disruption in 2--3 mum sections was observed. EZH revealed the absence of the classical mosaic pattern usually found in skeletal muscles. ATPase studies were inconsistent and did not correlate with the expected reciprocal activity of NAD-H diaphorase, particularly on the large fibres. Ultrastructural features consisted of vacuoles within myofilament bundles, "smearing" of Z bands, and "nemaline rods". Occasional myelin figures and lipid-like droplets were observed in subsarcolemmal spaces, associated with scattered clusters of glycogen granules. Abnormal mitochondria and subsarcolemmal inclusions of dense and granular material were conspicuous. "Leptomeric" profiles, "Zebra bodies", or "striated bodies" were noted in 8 EOM's, and an Hirano body was found in 1. The intramuscular nerves contained structures resembling "Luse bodies" in 7 cases. These observations suggest that EOM from individuals with and without strabismus possess unique structural characteristics suggestive of developmental and morphological disarrangement of contractile elements. Some of these changes might play a role in the pathogenesis of strabismus and in the development of clinical symptoms. These features are significantly different from striated skeletal muscle. Therefore the criteria used in the pathological evaluation and diagnosis of skeletal muscle disorders cannot be unequivocally applied to EOM investigations. These data establish the necessity to determine histological norms, ultrastructural patterns, and develop new enzyme histochemistry criteria for the evaluation of EOM. Only then can an acceptable comparison of EOM and skeletal muscle be made.

Adenosine Triphosphatases↗