CYTOCHEMICAL OBSERVATIONS ON THE RELATIONSHIP BETWEEN LYSOSOMES AND PHAGOSOMES IN KIDNEY AND LIVER BY COMBINED STAINING FOR ACID PHOSPHATASE AND INTRAVENOUSLY INJECTED HORSERADISH PEROXIDASE.
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After incubation of formalin-fixed, frozen sections of kidney and liver from peroxidase-treated rats in an azo dye medium for acid phosphatase, and after subsequent incubation of the same sections with benzidine, phagosomes were stained blue and lysosomes were stained red in the same cells. It was observed that newly formed phagosomes were separate from preexisting lysosomes in the tubule cells of the kidney and in the Kupffer cells of the liver at early periods after treatment with peroxidase. At later periods, the color reactions for acid phosphatase and peroxidase occurred in the same granules. The reaction of peroxidase decreased gradually and disappeared from the phago-lysosomes after 2 to 3 days, whereas the reaction for acid phosphatase persisted. In the liver, most of the injected protein was concentrated in large phagosomes located at the periphery of the cells lining the sinusoids. The peribiliary lysosomes showed a relatively weak reaction for peroxidase in the proximity of the portal veins. After pathological changes of permeability, phagosomes and lysosomes lost their normal location and fused, in the interior of many liver cells, to form large vacuoles or spheres. The effects of a reduced load of peroxidase and the effects of the pretreatment with another protein (egg white) on the phago-lysosomes of the kidney were tested. The relationship of the fusion of phagosomes with lysosomes to the size of normal and pathological phago-lysosomes was discussed. (+info)
POWASSAN VIRUS: MORPHOLOGY AND CYTOPATHOLOGY.
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Powassan virus, a North American tickborne group B arbovirus, multiplied after simultaneous inoculation into bottles or tubes of virus and trypsinized suspension of continuous-line cultures of rhesus monkey kidney cells, strain LLC-MK2. Cytopathic effects comprising cell rounding and cytoplasmic vacuolation were first observed five days after inoculation. Mixture of Powassan antiserum with virus before inoculation into tissue cultures inhibited the appearance of cytopathic effects. Hemagglutinins for rooster erythrocytes, optimally at pH 6.4 and 22 degrees C., first appeared in tissue culture supernatant fluids four days after inoculation.Electron microscopic observation of thin sections of infected tissue culture cells showed virus particles 360-380 A.U. along outer cell membranes and edges of cytoplasmic vacuoles. In phosphotungstic acid negatively stained preparations, intact virus particles, 400-450 A.U. total diameter, were observed inside infected cells. In particles in which the peripheral layer became discontinuous, geometrically arranged subunits compatible with cubic symmetry were observed. (+info)
INITIATION OF MITOSIS IN RELATION TO THE CELL CYCLE FOLLOWING FEEDING OF STARVED CHICKENS.
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Cellular proliferation of newly hatched chickens was depressed by starving them for 2.5 to 3.5 days. Starvation may hold proliferative cells in different parts of the cell cycle. In order to find where in the cell cycle these cells are held, the animals were fed and the following events were measured as a function of time after the start of feeding: (1) the mitotic index, and (2) the DNA synthetic index (number of cells in DNA synthesis 1 hour after injection of H(3)-thymidine). The duration of the cell's DNA synthetic period (S) was measured, permitting a more exact description of the cell cycle. Analysis of the duodenal and esophageal epithelia shows that feeding initiates cell division by stimulating cells from the G1 part of the mitotic cycle in the duodenum. In the esophagus some of the cells were either stopped or slowed down in G1, and another group of cells in G2. Feeding simultaneously stimulates both cell groups; the former moves into S, the latter into mitosis. The S period in starved animals is a little longer than that in normally fed animals but the extension can be attributed to a slightly decreased body temperature. (+info)
STUDY OF BULL SPERMATOZOA. QUANTITATIVE ELECTRON MICROSCOPY.
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The electron microscope has been used to determine the characteristic dimensions and the distribution of the dry mass in bull spermatozoa. The most important result is that all characteristic data are occurring in logarithmic distributions. Furthermore, no correlation between such parameters as head weight and tail weight or head length and tail length was found. The occurrence in logarithmic distributions and the non-correlation of parts in the assembly of a spermatozoon are considered to reflect significant biologic principles. Methodologically, a new procedure is added to quantitative electron microscopy permitting the recording of the mass cross-section (total mass per unit length) of an object. This approach makes possible determinations of the distribution and the total mass of very long and narrow structures. (+info)
DYNAMICS OF ACRIDINE ORANGE-CELL INTERACTION. II. DYE-INDUCED ULTRASTRUCTURAL CHANGES IN MULTIVESICULAR BODIES (ACRIDINE ORANGE PARTICLES).
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The brilliantly fluorescent cytoplasmic particles that accumulate in HeLa cells treated with acridine orange, previously referred to as acridine orange particles, are shown to represent acid phosphatase positive multivesicular bodies (MVB). Dynamic changes in the ultrastructure of these organelles may be induced by varying the concentration of extracellular dye and the length of exposure to the dye. Low concentrations of dye for long intervals of time lead to marked hypertrophy of the MVB and accumulation of myelin figures within them, the acid phosphatase activity being retained. High concentrations of dye for short time intervals lead initially to a diffuse distribution of dye through out the cytoplasm (cytoplasmic reddening) as viewed in the fluorescence microscope. When cells are stained in this way and incubated in a dye-free medium, the diffusely distributed dye is segregated into MVB within 1 hour. Ultrastructurally, these MVB show dilatation but no myelin figures. The process of dye segregation is energy dependent and will not occur in starved cells. This energy dependence and the occurrence of segregation via dilatation of the MVB rather than ultrastructural transformation, i.e. formation of new binding sites, suggests that the process involves an active transport mechanism. Of the various energy sources supplied to starved cells, only glucose, mannose, and pyruvate are fully effective in supporting dye segregation. Blockage of the tricarboxylic acid cycle with malonate inhibits the effects of pyruvate but not of glucose, demonstrating the efficacy of both the tricarboxylic acid and glycolytic cycles in supplying energy for the process. (+info)
STUDIES ON ANTIBODY PRODUCTION X. MODE OF FORMATION OF PLASMOCYTES IN CELL TRANSFER EXPERIMENTS.
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Cells from lymph nodes of rabbits injected repeatedly with bovine serum albumin were transferred subcutaneously to previously irradiated rabbits, and the recipients were immediately injected with bovine serum albumin. A good antibody response resulted. In a series of such animals killed on successive days, skin samples at sites of cell deposition were removed and examined by immunofluorescence and by light microscopy. In these tissues abundant plasmocytes were found to have multiplied and differentiated in a regular progression from immature, to medium, to mature plasmocytes. During the 6 days of the experiment the small plasmocytes accumulated until they reached 85 per cent of the total plasmocytic population. The mitotic index of the large and medium plasmocytes averaged 11 per cent, implying a generation time of 6.3 hours on the basis of a 1 hour mitotic time. This rate of growth is sufficiently rapid to account for all the plasmocytes on the 6th day as deriving from less than 1 per cent of the population initially transferred. This rate and the orderly progression in the evolution of the plasmocytic population, make it highly improbable that plasmocytes arise from transformation of lymphocytes, but rather indicate that they spring from specific precursors already present among the transferred cells. (+info)
THE ROLE OF TEMPERATE BACTERIOPHAGE IN THE PRODUCTION OF ERYTHROGENIC TOXIN BY GROUP A STREPTOCOCCI.
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Non-lysogenic, non-toxinogenic Group A streptococci when infected by temperate bacteriophages isolated from known scarlatinal toxin-producing strains acquire the capacity to form erythrogenic toxin. This toxin causes a characteristic erythematous reaction in the skin of rabbits and is readily neutralizable by standard scarlatinal antitoxins. The production of toxin appears to be related to the synthesis of mature phage particles since ultraviolet enhancement of phage production results in a concomitant increase in toxin titer. In contrast, there is no increase in the production of another extracellular product, deoxyribonuclease, by these lysogenized streptococci. Furthermore, cellular disruption studies indicate that the toxin probably does not exist in a preformed state within the cell. Double diffusion reactions in agar indicate that a newly formed protein appears in the lysogenic culture filtrate and is absent in the non-lysogenic filtrates. (+info)
OBSERVATIONS ON THE FINE STRUCTURE OF LUTEIN CELLS. II. THE EFFECTS OF HYPOPHYSECTOMY AND MAMMOTROPHIC HORMONE IN THE RAT.
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Corpus luteum formation was induced in 26-day-old rats which were subsequently hypophysectomized and injected with mammotrophic hormone (MH, LTH). Sections of corpora lutea from these animals were examined with the electron microscope and compared with similarly prepared (Caulfield's fixed, Araldite embedded) corpora from normal pregnancy and from controls, the latter consisting of corpora prior to hypophysectomy and corpora from uninjected rats 7 to 14 days after hypophysectomy. Lutein cells from corpora lutea of injected animals and of normal pregnancy are characterized by abundant, tortuous, tubular agranular endoplasmic reticulum and by mitochondria, many of which are disc-shaped with dense matrices and both villiform and lamelliform cristae. The endoplasmic reticulum is most abundant in lutein cells from pregnant animals, in which cells it is in the form of thin, highly tortuous tubules. The form of the lipid droplets seen in cells of stimulated animals varies greatly. Marginal foldings of the lutein cells on the perivascular space were found in all instances. Lutein cells from hypophysectomized animals have a less highly developed agranular endoplasmic reticulum. The mitochondria have irregular outlines and a relatively lucid matrix. The lipid droplets in these cells show less tendency to be extracted, but are not so large or abundant as in the cells of onset controls. Granules believed to contain lipid pigments are common in the lutein cells of these control animals. It is suggested that lutein cells from corpora lutea which are actively secreting progesterone may be readily distinguished from lutein cells from non-active corpora by means of the multiple characteristics enumerated. It is further suggested that mammotrophic hormone has a general effect on the metabolism of lutein cells rather than solely affecting a specific organelle, the abundance or composition of which may be the limiting factor in the production of progesterone. (+info)