Cytochemical studies of the multivesicular bodies

1990 ◽  
Vol 48 (3) ◽  
pp. 80-81
Author(s):  
Xueming Tang
Keyword(s):  
Electron Microscope ◽  
Leydig Cells ◽  
Sodium Acetate ◽  
Hydrolytic Enzymes ◽  
Multivesicular Bodies ◽  
Cerium Chloride ◽  
Sodium Acetate Buffer ◽  
Time Intervals ◽  
Adult Rat ◽  
Endocytic Activity

Multivesicular bodies were observed frequently in electron microscope photographs of Leydig cells from normal adult rat testes. Their formation, evolution and fate were analyzed morphologically in preparations treated to show cytidine monophosphatase ( CMPase ) activity and in animals sacrificed at various time intervals ranging from 5 minutes to 2 hours after a single intratesticular injection of cationic ferritin. The CMPase medium contains 2mM cerium chloride, 2mM cytidine monophosphate, 5mM manganese chloride and 40mM sodium acetate buffer ( pH 5.0 ) with 4% sucrose. Cationic ferritin was used as a tracer for demonstrating the endocytic activity of Leydig cells.Cytochemical experiments showed that, in contrast to lysosomes which were CMPase positive, the premultivesicular bodies and the pale multivesicular bodies were CMPase negative. The dense multivesicular bodies were frequently apposed to strongly reactive lysosomes and they aquire their hydrolytic enzymes by fusion with lysosomes and showed CMPase activity.

Endocytosis and the lysosomal apparatus of rat Leydig cells

1984 ◽  
Vol 42 ◽  
pp. 708-709
Author(s):  
M.F. Lalli ◽  
L. Hermo ◽  
Y. Clermont
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Cell Surface ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Extracellular Fluid ◽  
Multivesicular Bodies ◽  
Rat Testis ◽  
Endocytic Activity

The Leydig cells of the rat testis which are involved in testosterone production contain an abundance of smooth endoplasmic reticulum and mitochondria (Figs. 2,6). These cells also possess many peroxisomes, lysosomes and multivesicular bodies (MVB's). On the cell surface, the plasma membrane contains numerous short microvilli, small invaginations and large plasmalemmal folds which appear to engulf extracellular fluid. There are also many large dilated vacuoles adjacent to the cell surface. The purpose of the present study is to determine if these cells show endocytic activity and to differentiate by various cytochemical means lysosomal elements from peroxisomes.To identify lysosomes, tissue chopper sections of 2% glutaraldehyde-fixed testes (containing 2.5% dextran) were incubated in media containing thiamine monophosphate as a substrate (Lalli, 1983) to demonstrate the presence of acid phosphatase or in media containing P-nitrocatechol sulfate for the demonstration of arylsulfatase (Hopsu-Havu et al., 1967).

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

Smooth endoplasmic reticulum in perfusion and immersion-fixed Leydig cells

1990 ◽  
Vol 48 (3) ◽  
pp. 82-83
Author(s):  
R.T.F. Bernard ◽  
R.H.M. Cross
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Steroid Hormones ◽  
Transmission Electron Microscope ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Random Mixture ◽  
Transmission Electron

Smooth endoplasmic reticulum (SER) is involved in the biosynthesis of steroid hormones, and changes in the organisation and abundance of this organelle are regularly used as indicators of changes in the level of steroidogenesis. SER is typically arranged as a meshwork of anastomosing tubules which, with the transmission electron microscope, appear as a random mixture of cross, oblique and longitudinal sections. Less commonly the SER appears as swollen vesicles and it is generally suggested that this is an artefact caused during immersion fixation or during immersion of poorly-perfused tissue.During a previous study of the Leydig cells of a seasonally reproducing bat, in which tissue was fixed by immersion, we noted that tubular SER and vesicular SER often occured in adjacent cells and sometimes in the same cell, and that the abundance of the two types of SER changed seasonally. We came to doubt the widelyheld dogma that vesicular SER was an artefact of immersion fixation and set out to test the hypothesis that the method of fixation does not modify the ultrastructure of the SER.

Electron-Microscopic localization of biotinylated gastrin bound to eosinophils in the rat stomach

1994 ◽  
Vol 52 ◽  
pp. 300-301
Author(s):  
Caroline A. Miller ◽  
David H. Nichols ◽  
Richard F. Murphy
Keyword(s):  
Electron Microscope ◽  
Phosphate Buffer ◽  
Uranyl Acetate ◽  
List Type ◽  
Cerium Chloride ◽  
Rat Stomach ◽  
Electron Microscopic ◽  
Human Sequence ◽  
Acetate Lead ◽  
Microscope Slides

Gastrin is a small peptide capable of both stimulating gastric acid secretion and acting as an enteric growth factor. Known functions of eosinophils in the rat stomach are related to immunological defense. Here we demonstrate the binding of biotinylated gastrin to rat stomach eosinophils in the electron microscope. Small pieces of stomach were fixed by immersion in 4% paraformaldehyde/0.1% glutaraldehyde in 0.1 M phosphate buffer, pH 7.4 for 1 hour. The tissue was then cryoprotected in 30% sucrose/0.1 M phosphate buffer, transferred to Tissue Tek OCT compound and frozen in isopentane cooled with liquid nitrogen. Transverse cryostat sections were cut at 25 μm, thawed in PBS and free floating sections exposed to 10−5 M biotinylated 1-17 gastrin (human sequence; Peninsula Labs) for 1 hour. Controls omitted the biotinylated gastrin from this step. Sections were then rinsed 3X in PBS and exposed to either:1).a 1:50 dilution of 10 nm Extravidin colloidal gold (Sigma) for 2 hours, or2).an avidin-biotin-alkaline phosphatase complex (ABC-AP;Vector) for 1 hour. A substrate solution containing cerium chloride was used to generate an electron dense reaction product.Sections from both procedures were postfixed in 1% OsO4 in 0.1 M phosphate buffer, rinsed and dehydrated. These were then flat embedded in EMbed 812 between two microscope slides coated with Liquid Release (both from Electron Microscopy Sciences).Polymerized sections were adhered to resin blocks using super glue, cut at 70-90 nm, stained with uranyl acetate/lead citrate and observed in a Philips CM-10 electron microscope.

In Vitro Incorporation of Sodium Acetate-l-C14 into Leukocyte Lipids of Normal and Leukaemic Subjects as a Function of Incubation Time

1962 ◽  
Vol 02 (02) ◽  
pp. 165-172
Author(s):  
C Miras ◽  
G Lewis ◽  
J Mantzos
Keyword(s):  
Sodium Acetate ◽  
Linear Part ◽  
Lipid Synthesis ◽  
Normal Subjects ◽  
Cytostatic Agents ◽  
Time Intervals ◽  
Total Blood ◽  
Effect Of Treatment ◽  
Product Relation

Summary1. Separated leukocytes or total blood from normal subjects, untreated leukaemic patients and from leukaemic patients treated with cytostatic agents were incubated with CH3COONa-l-C14. Radioactivity of mixed lipids was measured at standard time intervals.2. The time incorporation curve observed with leukocytes from treated leukaemic patients showed after an initial linear part, a more rapid levelling off than the curves observed with leukocytes from untreated and normal subjects.3. Therefore, an indirect effect of treatment on leukocyte lipid synthesis seems to be present.4. Phospholipid and neutral lipid synthesis by leukaemic leukocytes was also studied. The results give no evidence that these fractions as a whole have any precursor-product relation.

Causes and prediction of changes in extractable phosphorus during flooding

Soil Research ◽  
1989 ◽  
Vol 27 (1) ◽  
pp. 45 ◽  
Author(s):  
IR Willett
Keyword(s):  
Organic Matter ◽  
Soil Ph ◽  
Sodium Acetate ◽  
Chemical Properties ◽  
Sodium Acetate Buffer ◽  
P Release ◽  
Reduction Of Iron ◽  
No Release ◽  
Extractable Phosphorus ◽  
A Minor

In a laboratory experiment, samples of 18 soils, which are known to be flooded in the field, were flooded for up to 32 days. Both untreated and phosphate-treated (50 mg P kg-1) soils were studied. It was attempted to identify which chemical properties measured on the dry untreated soils, and the changes in pH, Eh and extractable Fe and Mn over the flooding periods, controlled the changes in sodium acetate buffer (pH 3.0) extractable phosphorus during flooding. It was shown that the reduction of iron(III) oxides was the dominant source of the P released during flooding. However, the amount of P released was strongly inhibited by re-sorption. Direct measurement of the amount of iron(III) reduced during flooding and measurement of phosphate sorption were required to predict the amount of P released during flooding. Organic matter contributed toward the P released during flooding. Its contribution appeared to be by mineralization, rather than by accelerating FeIII reduction. The reduction of MnIII and MnIII was a minor source of P in the untreated soils. Changes in soil pH during flooding were responsible for desorption of freshly applied P, but did not appear to affect P release in the untreated soils. The Vertisols and some of the Alfisols showed very little, or no release of P during flooding.

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