scholarly journals A variant of the pyroantimonate technique suitable for localization of calcium in ovarian tissue.

1979 ◽  
Vol 27 (6) ◽  
pp. 1017-1028 ◽  
Author(s):  
B S Weakley
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Lipid Droplets ◽  
Microprobe Analysis ◽  
Smooth Endoplasmic Reticulum ◽  
Ovarian Tissue ◽  
Follicle Cells ◽  
Fixation Time ◽  
X Ray ◽  
Cytoplasmic Processes

Osmium-pyroantimonate solutions for the precipitation of cations are unsuitable for use with delicate mammalian oocytes. A variant of the pyroantimonate technique employing a mixture of pyroantimonate and glutaraldehyde has been found to give successful and repeatable results if a fixation time of 4 hr is used. Calcium-containing antimonate precipitates were localized principally in nuclei, smooth endoplasmic reticulum, Golgi apparatus, mitochondria, and cytoplasmic processes of both oocytes and follicle cells, and along the plasma membrane in small oocytes. Deposits were also concentrated around the periphery of lipid droplets in the follicle cells. The presence of calcium in the precipitates was confirmed by x-ray microprobe analysis.

scholarly journals STUDIES ON MICROPEROXISOMES II. A CYTOCHEMICAL METHOD FOR LIGHT AND ELECTRON MICROSCOPY

1972 ◽  
Vol 20 (12) ◽  
pp. 1006-1023 ◽  
Author(s):  
ALEX B. NOVIKOFF ◽  
PHYLLIS M. NOVIKOFF ◽  
CLEVELAND DAVIS ◽  
NELSON QUINTANA
Keyword(s):  
Endoplasmic Reticulum ◽  
Guinea Pig ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Distal Tubule ◽  
Striking Difference ◽  
High Concentration ◽  
Electron Microscopic ◽  
Pig Kidney

A modification of the Novikoff-Goldfischer alkaline 3,3'-diaminobenzidine medium for visualizing peroxisomes is described. It makes possible light microscopic as well as electron microscopic studies of a recently described class of peroxisomes, the microperoxisomes. Potassium cyanide (5 x 10–3 M) is included in the medium to inhibit mitochondrial staining, the pH is 9.7 and there is a high concentration of H2O2 (0.05%). Two cell types have been chosen to illustrate the advantages of the new procedure for demonstrating the microperoxisomes: the absorptive cells in the human jejunum and the distal tubule cells in the guinea pig kidney. Suggestive relations of microperoxisomes and lipid are described in the human jejunum. The microperoxisomes are strategically located between smooth endoplasmic reticulum that radiates toward the organelles and contains lipid droplets and "central domains" of highly specialized endoplasmic reticulum which do not show the lipid droplets. The microperoxisomes are also present at the periphery of large lipid-like drops. In the guinea pig kidney tubule there is a striking difference between the thick limb of Henle and distal tubule. The distal tubule has a population of cells with large numbers of microperoxisomes readily visible by light microscopy; these cells are not present in the thick limb of Henle. Other differences between the two are also described.

scholarly journals Apolipoprotein L1-Specific Antibodies Detect Endogenous APOL1 inside the Endoplasmic Reticulum and on the Plasma Membrane of Podocytes

2020 ◽  
Vol 31 (9) ◽  
pp. 2044-2064 ◽  
Author(s):  
Suzie J. Scales ◽  
Nidhi Gupta ◽  
Ann M. De Mazière ◽  
George Posthuma ◽  
Cecilia P. Chiu ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Cell Surface ◽  
High Frequency ◽  
Lipid Droplets ◽  
Human Kidney ◽  
Cytoplasmic Face ◽  
Large Panel ◽  
Surface Localization ◽  
Apolipoprotein L1

BackgroundAPOL1 is found in human kidney podocytes and endothelia. Variants G1 and G2 of the APOL1 gene account for the high frequency of nondiabetic CKD among African Americans. Proposed mechanisms of kidney podocyte cytotoxicity resulting from APOL1 variant overexpression implicate different subcellular compartments. It is unclear where endogenous podocyte APOL1 resides, because previous immunolocalization studies utilized overexpressed protein or commercially available antibodies that crossreact with APOL2. This study describes and distinguishes the locations of both APOLs.MethodsImmunohistochemistry, confocal and immunoelectron microscopy, and podocyte fractionation localized endogenous and transfected APOL1 using a large panel of novel APOL1-specific mouse and rabbit monoclonal antibodies.ResultsBoth endogenous podocyte and transfected APOL1 isoforms vA and vB1 (and a little of isoform vC) localize to the luminal face of the endoplasmic reticulum (ER) and to the cell surface, but not to mitochondria, endosomes, or lipid droplets. In contrast, APOL2, isoform vB3, and most vC of APOL1 localize to the cytoplasmic face of the ER and are consequently absent from the cell surface. APOL1 knockout podocytes do not stain for APOL1, attesting to the APOL1-specificity of the antibodies. Stable re-transfection of knockout podocytes with inducible APOL1-G0, -G1, and -G2 showed no differences in localization among variants.ConclusionsAPOL1 is found in the ER and plasma membrane, consistent with either the ER stress or surface cation channel models of APOL1-mediated cytotoxicity. The surface localization of APOL1 variants potentially opens new therapeutic targeting avenues.

scholarly journals Targeted disruption of the aromatase P450 gene (Cyp19) in mice and their ovarian and uterine responses to 17beta-oestradiol

2001 ◽  
Vol 170 (1) ◽  
pp. 99-111 ◽  
Author(s):  
K Toda ◽  
K Takeda ◽  
T Okada ◽  
S Akira ◽  
T Saibara ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Corpus Luteum ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Ovarian Follicles ◽  
Interstitial Cells ◽  
Aromatase Activity ◽  
Tubular Structures ◽  
Wild Type ◽  
Targeted Disruption

Aromatase P450 (CYP19) is an enzyme catalysing the conversion of androgens into oestrogens. We generated mice lacking aromatase activity (ArKO) by targeted disruption of Cyp19 and report the characteristic features of the ArKO ovaries and uteri as revealed by histological and biochemical analyses. ArKO females were totally infertile but there were as many developing follicles in their ovaries at 8 weeks of age as in wild-type ovaries. Nevertheless, no typical corpus luteum was observed in the ArKO ovaries. Electron microscopy revealed the presence of well-developed smooth endoplasmic reticulum, few lipid droplets and mitochondria with less organized tubular structures in the ArKO luteinized interstitial cells. These ultrastructural features were different from those of the wild-type interstitial cells, where there are many lipid droplets and mitochondria with well-developed tubular structures, characteristic of steroid-producing cells. When ArKO mice were supplemented with 17beta-oestradiol (E(2); 15 microg/mouse) every fourth day from 4 weeks of age for 1 month, increased numbers of follicles were observed in the ovaries as compared with those of untreated ArKO mice, although no typical corpus luteum was detectable. Ultrastructural analysis revealed the disappearance of the accumulated smooth endoplasmic reticulum in the luteinized interstitial cells after E(2 )supplementation. Transcripts of pro-apoptotic genes such as p53 and Bax genes were markedly elevated in the ArKO ovaries as compared with those of wild-type mice. Although E(2) supplementation did not cause suppression of the elevated expression of p53 and Bax mRNAs, it caused marked enhancement of expression levels of lactoferrin and progesterone receptor mRNAs in the uteri as well as increases in uterine wet weight. At 8 months of age, ArKO mice developed haemorrhages in the ovaries, in which follicles were nearly depleted, while age-matched wild-type females still had many ovarian follicles. Furthermore, macrophage-like cells were occasionally observed in the ArKO ovarian follicles. These results suggested that targeted disruption of Cyp19 caused anovulation and precocious depletion of ovarian follicles. Additionally, analysis of mice supplemented with E(2) demonstrated that E(2) apparently supports development of ovarian follicles, although it did not restore the defect in ovulation.

scholarly journals Ultrastructural Changes in the Liver of Intravenous Heroin Addicts

2010 ◽  
Vol 10 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Goran Ilić ◽  
Radovan Karadžić ◽  
Lidija Kostić-Banović ◽  
Jovan Stojanović ◽  
Aleksandra Antović
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Liver Tissue ◽  
Smooth Endoplasmic Reticulum ◽  
Decisive Role ◽  
Basal Membrane ◽  
Ultrastructural Changes ◽  
Heroin Addicts ◽  
Transmission Electron ◽  
Ultrastructural Findings

The ultrastructural research has a decisive role in gathering the knowledge on the liver’s response to the influence of some drugs. The aim of the study was to perform an ultrastructurai analysis of the liver in chronic intravenous heroin addicts.The study involved the autopsy conducted on 40 bodies of intravenous heroin addicts and 10 control autopsies. The liver tissue was fixed in glutaraldehyde and moulded with epon for investigation purposes of ultrastructural changes. The analysis was performed using the method of transmission electron microscopy.In the group of intravenous heroin addicts, the liver autopsy samples showed degenerative vesicular and fat changes, chronic active and persistent hepatitis, cirrhosis, reduction in the amount of glycogen in hepatocytes, as well as the Kupffer cell’s dominant hypertrophy. Various changes occur in organelles, plasma membrane of hepatocytes and biliary channels as well as in the nucleus.The most important ultrastructural findings include: hyperplasia and hypertrophy of the smooth endoplasmic reticulum, which is histologically proven vesicular degeneration of hepatocyte occurring as a result of the increased synthesis of enzymes of smooth endoplasmic reticulum due to chronic intravenous heroin intake, and the presence of continuous basal membrane followed by transformation of the sinusoids into capillaries (in the cases of chronic active hepatitis and cirrhosis) which leads to a disorder of microcirculation and further progress of cirrhosis.

scholarly journals Ultrastructural analysis of the dorsal body gland of the terrestrial snail Megalobulimus abbreviatus (Becquaert, 1948)

2010 ◽  
Vol 70 (2) ◽  
pp. 341-350 ◽  
Author(s):  
GD Moraes ◽  
M. Achaval ◽  
MM Dal Piva ◽  
MC Faccioni-Heuser ◽  
GF Wassermann ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Lipid Droplets ◽  
Neural Control ◽  
Smooth Endoplasmic Reticulum ◽  
Nerve Endings ◽  
Retrograde Labelling ◽  
Axon Terminals ◽  
Cerebral Ganglia ◽  
Reproductive Gland

The ultrastructure of the reproductive gland, dorsal body (DB), of Megalobulimus abbreviatus was analysed. Electron microscope immunohistochemistry was used to detect FMRFamide-like peptides in the nerve endings within this gland. Nerve backfilling was used in an attempt to identify the neurons involved in this innervation. In M. abbreviatus, the DB has a uniform appearance throughout their supraesophageal and subesophageal portions. Dorsal body cells have several features in common with steroid-secreting gland cells, such as the presence of many lipid droplets, numerous mitochondria with tubular cristae and a developed smooth endoplasmic reticulum cisternae. Throughout the DB in M. abbreviatus numerous axonal endings were seen to be in contact with the DB cells exhibiting a synaptic-like structure. The axon terminals contained numerous electron-dense and scanty electron-lucid vesicles. In addition, the DB nerve endings exhibited FMRFamide immunoreactive vesicles. Injection of neural tracer into the DB yielded retrograde labelling of neurons in the metacerebrum lobe of the cerebral ganglia and in the parietal ganglia of the subesophageal ganglia complex. The possibility that some of these retrograde-labelled neurons might be FMRFamide-like neurons that may represent a neural control to the DB in M. abbreviatus is discussed.

Histopathologic and Ultrastructural Alterations of White Liver Disease in Sheep Experimentally Depleted of Cobalt

1997 ◽  
Vol 34 (6) ◽  
pp. 575-584 ◽  
Author(s):  
S. Kennedy ◽  
S. McConnell ◽  
H. Anderson ◽  
D. G. Kennedy ◽  
P. B. Young ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Body Weight ◽  
Liver Disease ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Plasma Concentrations ◽  
Fatty Degeneration ◽  
Vitamin B ◽  
Liver Lesions ◽  
Lipofuscin Granules

Many cobalt-deficient sheep develop liver lesions known as ovine "white liver" disease, but the etiology of these changes is controversial. It has been suggested that cofactors are required for development of liver damage in cobalt-deficient sheep. In this study, one group of lambs ( n=5) was fed a diet low in cobalt (4.5 μg/kg) while a group of control lambs ( n=4) received the same diet after it had been supplemented with cobalt (1000 μg/kg). All cobalt-depleted lambs had reduced growth rate, anorexia, lacrimation, and alopecia, and they eventually became emaciated (mean body weight at end of study: 83% of initial body weight). Plasma concentrations of bilirubin and serum activity of glutamate-oxaloacetate transferase were elevated in these animals, while plasma concentrations of vitamin B12 were reduced (less than 220 pmol/L from day 42). Fatty degeneration of the liver associated with reduced concentrations of vitamin B12 (14.5 pmol/g) was seen in these animals at necropsy at 196 days. Microscopic liver lesions included accumulation of lipid droplets and lipofuscin particles in hepatocytes, dissociation and necrosis of hepatocytes, and sparse infiltration by neutrophils, macrophages, and lymphocytes. Ultrastructural hepatocytic alterations included swelling, condensation and proliferation of mitochondria, hypertrophy of smooth endoplasmic reticulum, vesiculation and loss of arrays of rough endoplasmic reticulum, and accumulation of lipid droplets and lipofuscin granules in cytoplasm of hepatocytes. No liver lesions were seen in control lambs. The results of this study indicate that cofactors are not a prerequisite to development of hepatic damage in cobalt-deficient sheep. Reduced activities of the vitamin B12-dependent enzymes, methylmalonyl CoA mutase and methionine synthase, and lipid peroxidation are of likely pathogenetic importance in the development of the lesions.

Sporogonic development of Haemoproteus meleagridis (Haemosporina: Haemoproteidae) in Culicoides edeni (Diptera: Ceratopogonidae)

1991 ◽  
Vol 69 (7) ◽  
pp. 1880-1888 ◽  
Author(s):  
Carter T. Atkinson
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Metabolism ◽  
Outer Surface ◽  
Blood Meal ◽  
Lipid Droplets ◽  
Smooth Endoplasmic Reticulum ◽  
Polar Ring ◽  
Membrane Complex ◽  
Inner Membrane Complex ◽  
Crystalloid Body

Mature oocysts of Haemoproteus meleagridis developed in specimens of Culicoides edeni within 3–6 days after the midges took a blood meal from an infected domestic turkey. Approximately 50 sporozoites budded from the surface of a single sporoblast body. Sporogonic development was similar to that of reptilian, avian, and mammalian haemoproteids that are transmitted by ceratopogonid and tabanid flies, but unlike that of hippoboscid-transmitted species in birds, which form large, slowly developing oocysts with multiple sporoblast bodies. Ultrastructural features of developing oocysts included nuclei with prominent nucleoli, mitochondria, and sandwich-like arrays of crystalloid particles and smooth endoplasmic reticulum (ER) that were present on the outer surface of developing lipid droplets during early stages of sporogony. During budding of sporozoites, crystalloid particles measuring 30–40 nm in diameter were associated with the inner membrane complex of the sporozoite pellicle, arranged in rows between subpellicular microtubules. Mature sporozoites contained an apical complex composed of a polar ring with two anterior apical rings, from two to eight elongate rhoptries, 22 evenly spaced subpellicular microtubules, and a small anterior crystalloid body. Morphological similarities between the ER–crystalloid arrays and the ER–microperoxisome arrays that have been described in cells actively engaged in lipid biosynthesis suggest that the crystalloid body contains enzymes important in lipid metabolism.

scholarly journals Studies on the glycosylation of hydroxylysine residues during collagen biosynthesis and the subcellular localization of collagen galactosyltransferase and collagen glucosyltransferase in tendon and cartilage cells

1975 ◽  
Vol 152 (2) ◽  
pp. 291-302 ◽  
Author(s):  
Richard Harwood ◽  
Michael E. Grant ◽  
David S. Jackson
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Specific Activity ◽  
Smooth Endoplasmic Reticulum ◽  
Gradient Centrifugation ◽  
Subcellular Fractions ◽  
Anterior Lens Capsule ◽  
Cartilage Cells ◽  
Membrane Bound ◽  
And Cartilage

1. The glycosylation of hydroxylysine during the biosynthesis of procollagen by embryonic chick tendon and cartilage cells was examined. When free and membrane-bound ribosomes isolated from cells labelled for 4min with [14C]lysine were assayed for hydroxy[14C]lysine and hydroxy[14C]lysine glycosides, it was found that hydroxylation took place only on membrane-bound ribosomes and that some synthesis of galactosylhydroxy[14C]lysine and glucosylgalactosylhydroxy[14C]lysine had occurred on the nascent peptides. 2. Assays of subcellular fractions isolated from tendon and cartilage cells labelled for 2h with [14C]lysine demonstrated that the glycosylation of procollagen polypeptides began in the rough endoplasmic reticulum. 14C-labelled polypeptides present in the smooth endoplasmic reticulum and Golgi fractions were glycosylated to extents almost identical with the respective secreted procollagens. 3. Assays specific for collagen galactosyltransferase and collagen glucosyltransferase are described, using as substrate chemically treated bovine anterior-lens-capsule collagen. 4. When homogenates were assayed for the collagen glycosyltransferase activities, addition of Triton X-100 (0.01%, w/v) was found to stimulate enzyme activities by up to 45%, suggesting that the enzymes were probably membrane-bound. 5. Assays of subcellular fractions obtained by differential centrifugation for collagen galactosyltransferase activity indicated the specific activity to be highest in the microsomal fractions. Similar results were obtained for collagen glucosyltransferase activity. 6. When submicrosomal fractions obtained by discontinuous-sucrose-density-gradient-centrifugation procedures were assayed for these enzymic activities, the collagen galactosyltransferase was found to be distributed in the approximate ratio 7:3 between rough and smooth endoplasmic reticulum of both cell types. Similar determinations of collagen glucosyltransferase indicated a distribution in the approximate ratio 3:2 between rough and smooth microsomal fractions. 7. Assays of subcellular fractions for the plasma-membrane marker 5′-nucleotidase revealed a distribution markedly different from the distributions obtained for the collagen glycosyltransferase. 8. The studies described here demonstrate that glycosylation occurs early in the intracellular processing of procollagen polypeptides rather than at the plasma membrane, as was previously suggested.

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