Wall structure and ornamentation of the urediniospores of Uromyces viciae-fabae

1987 ◽  
Vol 65 (10) ◽  
pp. 2007-2016 ◽  
Author(s):  
A. M. Woods ◽  
A. Beckett
Keyword(s):  
Endoplasmic Reticulum ◽  
Chemical Change ◽  
Spore Wall ◽  
Wall Structure ◽  
Colloidal Iron ◽  
Cytochemical Localization ◽  
Enzymic Digestion ◽  
Stage Of Development ◽  
Temperature Scanning

The development of the spines and the structure and composition of the urediniospore wall of Uromyces viciae-fabae have been studied by low-temperature scanning electron microscopy, cytochemical localization, chemical, and enzymic digestion techniques. Spine formation was similar to that previously described for urediniospores of other rust fungi. Swollen collars that are distinct from the annular ridges are only evident in frozen-hydrated spores and surround the bases of spines. Pockets of endoplasmic reticulum line the periphery of spores and mark the sites of spine development. This endoplasmic reticulum may have a role in the production of enzymes and (or) structural proteins or glycoproteins. Microfibrils are present in digested and shadowed wall preparations, often associated with spines. Enzymic digestion treatment suggests that these microfibrils are chitin. Around the bases of the spines, microfibrils are orientated circumferentially and contribute in part to the thickened, annular ridges evident in all spore preparations. The spore wall matrix consists of polysaccharides. Colloidal iron staining indicates acid mucopolysaccharides. Differences in reaction of the urediniospore wall to colloidal iron at what appears to be the same stage of development suggests in situ chemical change(s), which may in turn be linked with changes in wall plasticity.

Ultrastructure and development of urediospore ornamentation in Melampsora lini

1971 ◽  
Vol 49 (12) ◽  
pp. 2067-2073 ◽  
Author(s):  
L. J. Littlefield ◽  
C. E. Bracker
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Outer Surface ◽  
Spore Wall ◽  
Wall Material ◽  
Wild Type ◽  
Melampsora Lini ◽  
Inner Surface ◽  
External Position ◽  
Basal Portion

The urediospores of Melampsora lini (Ehrenb.) Lev. are echinulate, with spines ca. 1 μ long over their surface. The spines are electron-transparent, conical projections, with their basal portion embedded in the electron-dense spore wall. The entire spore, including the spines, is covered by a wrinkled pellicle ca. 150–200 Å thick. The spore wall consists of three recognizable layers in addition to the pellicle. Spines form initially as small deposits at the inner surface of the spore wall adjacent to the plasma membrane. Endoplasmic reticulum occurs close to the plasma membrane in localized areas near the base of spines. During development, the spore wall thickens, and the spines increase in size. Centripetal growth of the wall encases the spines in the wall material. The spines progressively assume a more external position in the spore wall and finally reside at the outer surface of the wall. A mutant strain with finely verrucose spores was compared to the wild type. The warts on the surface of the mutant spores are rounded, electron-dense structures ca. 0.2–0.4 μ high, in contrast to spines of the wild type. Their initiation near the inner surface of the spore wall and their eventual placement on the outer surface of the spore are similar to that of spines. The wall is thinner in mutant spores than in wild-type spores.

scholarly journals Cytochemical localization of a "basic" ATPase to canine myocardial surface membrane.

1980 ◽  
Vol 28 (12) ◽  
pp. 1286-1294 ◽  
Author(s):  
N N Malouf ◽  
G Meissner
Keyword(s):  
Cardiac Muscle ◽  
Microsomal Fraction ◽  
Surface Membrane ◽  
Buoyant Density ◽  
Membrane Structures ◽  
Intercalated Disc ◽  
Cytochemical Localization ◽  
Fixed Tissue ◽  
T System

Enzymatic properties of a canine cardiac muscle microsomal fraction were determined to localize in situ a "basic," divalent cation dependent adenosine triphosphatase (ATPase) by ultrastructural cytochemistry. The microsomal fraction had a buoyant density of 1.08--1.13 (20--30% [w/w] sucrose) and hydrolyzed adenosine triphosphate in the presence of Mg2+, Ca2+, Mn2+, or Co2+, but not in that of Sr2+ or Ni2+, under conditions that inhibited interfering (Na+ + K+)-ATPase and sarcoplasmic reticulum Ca2+-ATPase activities. "Basic" ATPase was localized in paraformaldehyde-fixed tissue in a medium containing Mg2+ or a high Ca2+ concentration (4 mM). A free Pb2+ concentration of less than 1 microM was used to capture enzymatically released phosphate anions. Electron-dense lead precipitates were present at the plasmalemma, T-system, and intercalated disc membranes with the exception of the nexus. These studies suggest that "basic" ATPase activity is associated with surface membrane structures of canine cardiac muscle.

FINE STRUCTURE IN CELLS OF PEA AND WHEAT EMBRYOS

1959 ◽  
Vol 37 (1) ◽  
pp. 65-72 ◽  
Author(s):  
G. Setterfield ◽  
H. Stern ◽  
F. B. Johnston
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membranes ◽  
Osmic Acid ◽  
Dense Granules ◽  
Cytoplasmic Bodies ◽  
Wheat Embryos ◽  
Electron Microscopes ◽  
Cell Fractions ◽  
Isolated Cell

To provide a basis for relating biochemical findings on isolated cell fractions to cytological structure in situ, embryos of pea and wheat were fixed with osmic acid, sectioned, and observed in phase-contrast and electron microscopes. The nuclei of all cells were similar, showing nuclear membranes, chromosomes, and prominent nucleoli. The cytoplasm contained highly developed structure which presumably reflected the incipient growth condition of the cells. Several cytoplasmic components were common to both embryos: small dense granules, endoplasmic reticulum, mitochondria, presumed proplastids, amyloplasts, irregular bodies, plasma membranes, and plasmodesmata. The small dense granules, presumably ribonucleoprotein particles, occurred profusely, both free and in association with extensively developed endoplasmic reticulum. These particles are probably responsible for the microsomal fractions obtainable from embryos and seedlings. The mitochondria were usually relatively small (0.25−0.5 μ diameter) although groups of very long (5 μ) ones were occasionally found. Bodies resembling mitochondria in size and shape, but lacking cristae, were present and represent either immature mitochondria or proplastids. Reserve material occurred as starch in structurally complex amyloplasts and possibly as protein in the irregular bodies. In addition to these structures cells of the wheat embryos remote from the meristems contained prominent cytoplasmic bodies classified as "dense" and "thick-walled". The dense bodies probably represent stored lipids while the significance of the thick-walled bodies, which showed a variety of forms, is unknown.

The initiation of basal disc formation in Dictyostelium discoideum is an early event in culmination

Development ◽  
1996 ◽  
Vol 122 (3) ◽  
pp. 753-760 ◽  
Author(s):  
K. Jermyn ◽  
D. Traynor ◽  
J. Williams
Keyword(s):  
Early Event ◽  
Double Staining ◽  
Forward Movement ◽  
Basal Disc ◽  
Stage Of Development ◽  
Glucuronidase Reporter ◽  
Tip Formation ◽  
Beta Galactosidase ◽  
Disc Formation

We have analysed expression of the ecmA and ecmB genes of Dictyostelium by enzymatic double staining using beta-galactosidase and beta-glucuronidase reporter gene constructs. Cells expressing the ecmA gene first appear as scattered cells at the mound stage of development and we show that this is also true for cells expressing the ecmB gene. During tip formation the ecmA-expressing cells move to the apex of the mound, while the ecmB-expressing cells accumulate in the base. The ecmB-expressing cells constitute part of the basal disc if the culminant is formed in situ but are discarded if a migratory slug is formed. During slug migration they are replaced by a band of ecmB-expressing cells, situated in the front half of the prespore zone and tightly apposed to the substratum. When culmination is triggered these cells rapidly move to the back half of the prestalk zone, possibly acting as a point of attachment to the substratum. Ultimately, they are joined by cells at the back of the slug, the rearguard cells, to form the basal disc. Thus, contrary to previous belief, basal disc formation is initiated very early during culmination and occurs by the forward movement of cells located in the anterior of the prespore zone.

scholarly journals Mitochondria Endoplasmic Reticulum Contact Sites (MERCs): Proximity Ligation Assay as a Tool to Study Organelle Interaction

2021 ◽  
Vol 9 ◽  
Author(s):  
Sara Benhammouda ◽  
Anjali Vishwakarma ◽  
Priya Gatti ◽  
Marc Germain
Keyword(s):  
Endoplasmic Reticulum ◽  
Fluorescence Probes ◽  
Proximity Ligation Assay ◽  
Proximity Ligation ◽  
Membrane Contact Sites ◽  
Contact Sites ◽  
Membrane Contact ◽  
Endogenous Proteins ◽  
Underlying Mechanisms

Organelles cooperate with each other to regulate vital cellular homoeostatic functions. This occurs through the formation of close connections through membrane contact sites. Mitochondria-Endoplasmic-Reticulum (ER) contact sites (MERCS) are one of such contact sites that regulate numerous biological processes by controlling calcium and metabolic homeostasis. However, the extent to which contact sites shape cellular biology and the underlying mechanisms remain to be fully elucidated. A number of biochemical and imaging approaches have been established to address these questions, resulting in the identification of a number of molecular tethers between mitochondria and the ER. Among these techniques, fluorescence-based imaging is widely used, including analysing signal overlap between two organelles and more selective techniques such as in-situ proximity ligation assay (PLA). While these two techniques allow the detection of endogenous proteins, preventing some problems associated with techniques relying on overexpression (FRET, split fluorescence probes), they come with their own issues. In addition, proper image analysis is required to minimise potential artefacts associated with these methods. In this review, we discuss the protocols and outline the limitations of fluorescence-based approaches used to assess MERCs using endogenous proteins.

scholarly journals CYTOCHEMICAL LOCALIZATION OF ACID MUCOSUBSTANCES WITHIN RABBIT, CHICKEN, FROG AND FISH SKELETAL MUSCLE FIBERS

1969 ◽  
Vol 17 (1) ◽  
pp. 36-46 ◽  
Author(s):  
WILLIAM J. DOUGHERTY
Keyword(s):  
Alcian Blue ◽  
Skeletal Muscles ◽  
Phase Contrast ◽  
Blue Staining ◽  
Polarization Microscopy ◽  
Rabbit Muscle ◽  
Colloidal Iron ◽  
Cytochemical Localization ◽  
High Iron ◽  
Acid Mucosubstances

Skeletal muscles of rabbits, chickens, frogs and fishes were studied by bright field, phase contrast and polarization microscopy after treatment with: (1) Alcian Blue, pH 2.5, (2) Alcian Blue, pH 1.0, (3) low iron diamine, (4) high iron diamine, (5) dialyzed iron, pH 2.0, and (6) colloidal iron, pH 1.5. A prominent aspect of each of the muscles studied was transverse muscle bands which stained with Alcian Blue at pH 2.5, low iron diamine and dialyzed and colloidal iron reagents. Staining of transverse bands was not very intense with these reagents, suggesting that the materials demonstrated occurred in relatively low concentrations. Staining of transverse bands in chicken, frog and fish muscles was observed also after treatment with Alcian Blue at pH 1.0 or with high iron diamine. Staining of rabbit muscle with Alcian Blue at pH 1.0 or with high iron diamine was not detectable even after the most effective fixatives employed in this study, viz., Carony's fixative or buffered HgCl2. Phase contrast and polarization microscopy indicated that the transverse bands stained by the reagents employed corresponded to the I bands in agreement with previous electron cytochemical studies of skeletal muscles treated with dialyzed iron at controlled pH. Methylation for 4 hr at 60°C prevented I band staining with Alcian Blue and dialyzed iron in each of the muscles studied. Treatment of muscle sections with Vibrio cholerae neuraminidase, testicular hyaluronidase or ribonuclease under optimal conditions did not prevent Alcian Blue staining of I bands. Trypsin treatment of muscle sections did not prevent I band staining except when digestion was prolonged to the point that muscle striations were no longer recognizable. Saponification prior to hyaluronidase treatment reduced I band staining in each of the muscles studied. Saponification alone and saponification prior to neuraminidase digestion left I band alcianophilia intact. It was concluded that myofibrillar I bands of rabbit, chicken, frog and fish skeletal muscles contain acid mucosubstances. It was suggested that in each of these organisms an esterified, hyaluronic acid-like molecule is present within the I bands. Sulfated mucosaccharides occur as additional components in the I bands of fish, chicken and frog skeletal muscles; sulfated mucosaccharides apparently are not present in rabbit muscle I bands. Available evidence indicates that sialomucins are not present in the myofibrils of the organisms studied. The possible functional significance of I band acid mucosubstances in vertebrate skeletal muscles was discussed.

Heterogeneity of phospholipid synthesis in rat liver endoplasmic reticulum during proliferation of smooth membranes

1976 ◽  
Vol 22 (1) ◽  
pp. 173-197
Author(s):  
J.A. Higgins
Keyword(s):  
Endoplasmic Reticulum ◽  
Uniform Distribution ◽  
Specific Activity ◽  
Intact Cell ◽  
Smooth Endoplasmic Reticulum ◽  
Membrane Phospholipid ◽  
Phospholipid Synthesis ◽  
Protein Ratio ◽  
Cytochemical Localization ◽  
Heterogeneous Distribution

During proliferation of smooth endoplasmic reticulum (SER) induced by phenobarbital the specific activity of acyltransferases of the smooth microsomes increases, there is a transient rise in the phospholipid/protein ratio of these membranes, and an increased incorporation of [14C]glycerol into smooth-membrane phospholipid. Microsomes separated into subfractions on 2 gradients exhibited a heterogeneous distribution of these characteristics, indicating a non-uniform distribution of the site of phospholipid synthesis in the ER under these conditions. Cytochemical localization of acyltransferases on whole liver and smooth and rough microsomes confirmed this heterogeneity, and indicated that the distribution of this activity was not restricted to any morphologically distinct site in the ER of the intact cell. After 4 days of phenobarbital treatment the increased membrane is restricted to lighter subfractions and is similar in distribution to that of increased acyltransferase activity. These results indicate that the synthesis of membrane phospholipid and the growth of the SER in response to phenobarbital is not uniform but occurs at randomly dispersed sites in the SER while proteins may be added preferentially at these sites resulting in a final uniform distribution.

Intracellular localization of types I and II collagen mRNA and endoplasmic reticulum in embryonic corneal epithelia

1991 ◽  
Vol 100 (1) ◽  
pp. 23-33 ◽  
Author(s):  
K.K. Svoboda
Keyword(s):  
Endoplasmic Reticulum ◽  
In Situ Hybridization ◽  
Laser Scanning ◽  
Intracellular Localization ◽  
Confocal Laser ◽  
Type I ◽  
Basal Cells ◽  
Double Labeling ◽  
Collagen Mrna

The intracellular distribution of endoplasmic reticulum (ER) and types I and II collagen mRNA was analyzed in whole-mount preparations of freshly isolated corneal epithelia using in situ hybridization combined with confocal laser scanning analysis. The ER stained with DiOC6 (3) was prominent in both the periderm and basal cells. The basal cell ER distribution was perinuclear in the center of the cells, but below the nucleus the ER occupied nearly all of the cytoplasm in a reticular pattern similar to that seen with TEM cross-sections. Initial single label in situ hybridization studies showed that both the periderm and basal cells were positive for both types I and II collagen mRNA. The collagen cDNA probes appeared perinuclear in the center of the basal cells, similar to the DiOC6(3) staining pattern. In double-labeling experiments, the two mRNAs that translate chains of type I collagen, alpha 1 and alpha 2, colocalized within the same cell. However, the hybridization of probes specific for type I and II collagen mRNAs had separate, but overlapping, distributions within the same cell.

The Development of Intracellular Membranes Concomitant with the Appearance of HCL Secretion in Oxyntic Cells of the Metamorphosing Bullfrog Tadpole

1969 ◽  
Vol 4 (3) ◽  
pp. 709-727
Author(s):  
GERTRUDE M. FORTE ◽  
L. LIMLOMWONGSE ◽  
J. G. FORTE
Keyword(s):  
Endoplasmic Reticulum ◽  
Apical Cell ◽  
Morphological Development ◽  
Structural Development ◽  
Gastric Glands ◽  
Cytoplasmic Matrix ◽  
Stage Of Development ◽  
Hcl Secretion ◽  
Bullfrog Tadpole

Bullfrog tadpole stomachs of various metamorphic stages were examined to determine the fine-structural development of oxyntic cells and to correlate observed morphological development with the capacity to secrete HCl. It was found that in vitro tadpole stomachs can consistently be stimulated to secrete acid by stage XXIV of metamorphosis, when tail reabsorption is nearly complete. Concomitant with the appearance of HCl secretion, identifiable oxyntic cells were found in the gastric glands. Prior to stage XXIV (stages XXI and XXII) the majority of cells present in the developing gastric glands exhibit features of cytological organization characteristic of undifferentiated cells: large nuclei, relatively scantry cytoplasm, and numerous ribosomal particles within the cytoplasmic matrix. The newly differentiated oxyntic cells of stage XXIV tadpole stomachs are recognizable by the accumulation of tubular members of the smooth-surfaced endoplasmic reticulum in the apical portion of the cells. These membranous structures appear to be formed by the Golgi complex which is extremely elaborate at this stage of development. As the animals complete metamorphosis (stage XXV) further development of the oxyntic cells occurs, especially the elaboration of the tubular components of the smooth-surfaced endoplasmic reticulum. The abundance of these membranous tubules within the apical cell regions and the pattern of their packing is similar to that observed in oxyntic cells of adult frogs. Also consistent with studies on adult frogs, structural alterations associated with HCl secretion were seen in the later stages of metamorphosis. In stages XXIV and XXV tadpole stomachs, which had been stimulated to secrete acid by addition of histamine, the apical surfaces of oxyntic cells were invested with long filamentous microvilli which projected into the glandular lumen. These observations support the hypothesis that membrane transformations play an integral role in the mechanism of HCl secretion and they implicate the morphogenesis of the smooth-surfaced endoplasmic reticulum as a basic prerequisite in the development of gastric secretory function.

Spatial- and temporal-restricted pattern for amelogenin gene expression during mouse molar tooth organogenesis

Development ◽  
1988 ◽  
Vol 104 (1) ◽  
pp. 77-85 ◽  
Author(s):  
M.L. Snead ◽  
W. Luo ◽  
E.C. Lau ◽  
H.C. Slavkin
Keyword(s):  
Gene Expression ◽  
In Situ Hybridization ◽  
Gene Transcription ◽  
Developmental Stages ◽  
Three Dimensional ◽  
Molar Tooth ◽  
Specific Expression ◽  
Amelogenin Gene ◽  
Stage Of Development

Position- and time-restricted amelogenin gene transcription was analysed in developing tooth organs using in situ hybridization with asymmetric complementary RNA probes produced from a cDNA specific to the mouse 26 × 10(3) Mr amelogenin. In situ analysis was performed on developmentally staged fetal and neonatal mouse mandibular first (M1) and maxillary first (M1) molar tooth organs using serial sections and three-dimensional reconstruction. Amelogenin mRNA was first detected in a cluster of ameloblasts along one cusp of the M1 molar at the newborn stage of development. In subsequent developmental stages, amelogenin transcripts were detected within foci of ameloblasts lining each of the five cusps comprising the molar crown form. The number of amelogenin transcripts appeared to be position-dependent, being more abundant on one cusp surface while reduced along the opposite surface. Amelogenin gene transcription was found to be bilaterally symmetric between the developing right and left M1 molars, and complementary between the M1 and M1 developing molars; indicating position-restricted gene expression resulting in organ stereoisomerism. The application of in situ hybridization to forming tooth organ geometry provides a novel strategy to define epithelial-mesenchymal signal(s) which are believed to be responsible for organ morphogenesis, as well as for temporal- and spatial-restricted tissue-specific expression of enamel extracellular matrix.

Sign in / Sign up

Export Citation Format

Share Document