Hyphal tip growth in Achlya. I. Cytoplasmic organization

1980 ◽  
Vol 26 (9) ◽  
pp. 1132-1140 ◽  
Author(s):  
T. W. Hill ◽  
J. T. Mullins
Keyword(s):  
Electron Microscopy ◽  
Fibrous Material ◽  
Tip Growth ◽  
Phosphotungstic Acid ◽  
Chromic Acid ◽  
Periodic Acid ◽  
Cytoplasmic Vesicles ◽  
Cytoplasmic Organization ◽  
Apical Vesicles ◽  
Hyphal Tip

Growing apices of Achlya ambisexttalis Raper hyphae were examined by electron microscopy using cytochemical techniques. Apical vesicles can be grouped into two major classes based upon size and cytochemical reactions. Vesicles of the most prominent class are about 150 nm in diameter and possess contents which appear fibrous in thin section. This fibrous material reacts positively with the periodic acid – silver methenamine (PASM) cytochemical test for polysaccharides. Most of these same vesicles also display IDPase activity, and a smaller number display acid phosphatase activity. Vesicles of the second class are about 80 nm in diameter, and include coated vesicles and others which react positively for IDPase activity. They show a negative PASM reaction in contrast with the larger vesicles. Some of these smaller vesicles are stained by the phosphotungstic acid – chromic acid (PTA–CrO3) stain, whereas 150-nm vesicles are not. The source of at least some vesicles of both major classes appears to be the Golgi apparatus. It is proposed that the IDPase activity and carbohydrate content of the 150-nm cytoplasmic vesicles could serve as useful markers in their isolation.

Hyphal tip growth in Achlya. II. Subcellular localization of cellulase and associated enzymes

1980 ◽  
Vol 26 (9) ◽  
pp. 1141-1146 ◽  
Author(s):  
T. W. Hill ◽  
J. T. Mullins
Keyword(s):  
Electron Microscopy ◽  
Tip Growth ◽  
Cellulase Activity ◽  
Single Type ◽  
Similar Distribution ◽  
Cytochemical Localization ◽  
Isolation And Characterization ◽  
Cytoplasmic Vesicles ◽  
Hyphal Tip

The isolation and characterization of cellulase-containing membranes of Achlya ainbisexnalis Raper was attempted by differential and density gradient centrifugations. Maximum cellulase activity was found at an isopycnic density of 1.19 g/cm3, although some activity was found at other densities. A similar distribution of activity was shown by IDPase, ATPase, UDPG transferase, and by sedimentable carbohydrate. The coequilibration and steady enrichment of these activities during purification suggests their presence in a single type of subcellular particle. It was not possible to identify clearly the particle(s) in question from isolated fractions by electron microscopy, but when compared with the cytochemical localization of carbohydrate and IDPase in intact hypha, cytoplasmic vesicles with 150-mm diameters seem to be likely candidates.

Cytological studies of the M-haustorium of Endocronartium harknessii: morphology and ontogeny

1988 ◽  
Vol 66 (5) ◽  
pp. 974-988 ◽  
Author(s):  
A. A. Hopkin ◽  
J. Reid
Keyword(s):  
Pinus Banksiana ◽  
Phosphotungstic Acid ◽  
Chromic Acid ◽  
Periodic Acid ◽  
Neck Region ◽  
Wall Layer ◽  
Calcofluor White ◽  
Transmission Electron ◽  
Endocronartium Harknessii ◽  
The Matrix

M-haustoria of the endocyclic rust Endocronartium harknessii (J. P. Moore) Y. Hirat. were examined with light and transmission electron microscopy in infected seedlings of Pinus banksiana Lamb. The haustoria developed from unspecialized cells of the intercellular hyphae, each of which appeared capable of producing several haustoria. The haustoria were distinct from the intercellular hyphae in possessing a narrow septate neck region which terminated in a globose haustorial body. Periodic acid – thiocarbohydrazide – silver proteinate and periodic acid – chromic acid – phosphotungstic acid staining provided evidence of an additional wall layer in the haustorial neck not evident in the intercellular hyphae and suggested that the extra-haustorial matrix contained polysaccharides of mixed linkage as well as lipids. However, cellulase extraction and the use of gold-bound wheat-germ lectin showed that neither cellulose nor chitin, respectively, was a component of the matrix. Both the haustoria and the matrix were separated from the host cytoplasm by the extrahaustorial membrane. This membrane stained positively with periodic acid – chromic acid – phosphotungstic acid, while the noninvaginated portion of the host plasmalemma with which it was continuous usually did not. The matrix fluoresced strongly when stained with aniline blue in an apparently compatible reaction. Other stains such as analinonapthalenesulphonic acid and Calcofluor white showed evidence of protein and polysaccharide in the fungal walls. Light and transmission electron microscope observations showed that penetration pegs formed as narrow tubular evaginations of the haustorial mother cell which caused inward displacement of the host cell wall. They retained their peg-like appearance as they entered the cell lumen, but eventually their distal ends enlarged to form typical globose haustorial bodies.

Immunohistochemical and Ultrastructural Features of Hepatocellular Cytoplasmic Globules in Venous Outflow Impairment

2019 ◽  
Vol 152 (5) ◽  
pp. 563-569
Author(s):  
Alessia Buglioni ◽  
Tsung-Teh Wu ◽  
Taofic Mounajjed
Keyword(s):  
Electron Microscopy ◽  
Random Distribution ◽  
Phosphotungstic Acid ◽  
Periodic Acid ◽  
Complement Protein ◽  
Budd Chiari Syndrome ◽  
Venous Outflow ◽  
Periodic Acid Schiff ◽  
Chiari Syndrome ◽  
Size Variability

Abstract Objectives To examine the immunohistochemical and ultrastructural features of hepatocellular cytoplasmic globules in venous outflow impairment (VOI). Methods Sixty-four liver core biopsies were screened. Patients with α-1 antitrypsin (AAT) deficiency were excluded. All biopsies were stained with H&E, Masson trichrome, periodic acid-Schiff with diastase digestion (PAS-D), phosphotungstic acid hematoxylin (PTAH), complement protein 4d (C4d) immunostain, and AAT immunostain. Electron microscopy was also performed. Results Hepatocellular globules were identified in 8% of in-house cases. Causes of VOI included heart failure and Budd-Chiari syndrome. The hepatocellular cytoplasmic globules showed size variability, random distribution, and positivity for PAS-D, PTAH, and AAT. C4d was inconsistently positive. Electron microscopy showed that the globules were lysosome-bound inclusions containing microfibrillar material and fibrinogen. Conclusions PAS-D–positive hepatocellular globules occur in VOI. They cross-react with AAT but have different appearance, localization, and ultrastructural composition from globules in AAT deficiency.

scholarly journals Surface ultrastructure and elasticity in growing tips and mature regions of Aspergillus hyphae describe wall maturation

Microbiology ◽  
2005 ◽  
Vol 151 (11) ◽  
pp. 3679-3688 ◽  
Author(s):  
Hui Ma ◽  
Laelie A. Snook ◽  
Susan G. W. Kaminskyj ◽  
Tanya E. S. Dahms
Keyword(s):  
Electron Microscopy ◽  
Tip Growth ◽  
Living Cells ◽  
Surface Ultrastructure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Young Branch ◽  
Hyphal Tip ◽  
Cryo Scanning Electron Microscopy ◽  
Scanning Electron

This study reports the first direct, high-resolution physical and structural evidence of wall changes during hyphal tip growth, visualized by atomic force microscopy (AFM) in Aspergillus nidulans. Images from AFM and cryo-scanning electron microscopy provided comparable information, but AFM was also able to image and physically probe living cells. AFM images showed changes in the surface ultrastructure of A. nidulans hyphae, from newly deposited walls at hyphal tips to fully mature walls, as well as additional changes at young branches arising from mature walls. Surface architecture during wall maturation correlated with changes in the relative viscoelasticity (compliance per unit applied force) of walls measured by force spectroscopy (FS) in growing A. nidulans hyphae. Growing tips showed greater viscoelasticity than mature walls, despite equal support from turgor. Branch tips had comparable viscoelasticity to hyphal tips, unlike the mature wall from which they grew. FS also revealed differences in surface hydrophilicity between newly deposited and mature walls, with the tips being more hydrophilic. The hydrophilicity of young branch tips was similar to that of hyphal tips, and different from that of mature walls. Taken together, AFM images and FS data suggest that the A. nidulans wall matures following deposition at the hyphal tip.

Demonstration of Retinal Glycogen with Silver Methenamine

1971 ◽  
Vol 29 ◽  
pp. 564-565
Author(s):  
A. W. Sedar ◽  
G. H. Bresnick
Keyword(s):  
Lactic Acid ◽  
Chromic Acid ◽  
Periodic Acid ◽  
Müller Cell ◽  
External Limiting Membrane ◽  
Electron Microscope Level ◽  
Reactive Process ◽  
Inner Limiting Membrane ◽  
Muller Cell ◽  
And Migration

After experimetnal damage to the retina with a variety of procedures Müller cell hypertrophy and migration occurs. According to Kuwabara and others the reactive process in these injuries is evidenced by a marked increase in amount of glycogen in the Müller cells. These cells were considered originally supporting elements with fiber processes extending throughout the retina from inner limiting membrane to external limiting membrane, but are known now to have high lactic acid dehydrogenase activity and the ability to synthesize glycogen. Since the periodic acid-chromic acid-silver methenamine technique was shown to demonstrate glycogen at the electron microscope level, it was selected to react with glycogen in the fine processes of the Müller cell that ramify among the neural elements in various layers of the retina and demarcate these cells cytologically. The Rhesus monkey was chosen as an example of a well vascularized retina and the rabbit as an example of a avascular retina to explore the possibilities of the technique.

Identification of the pulmonary syndrome hantavirus by direct and colloidal gold immune Electron Microscopy

1994 ◽  
Vol 52 ◽  
pp. 274-275
Author(s):  
C. D. Humphrey ◽  
C.S. Goldsmith ◽  
L. Elliott ◽  
S.R. Zaki
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Monoclonal Antibody ◽  
Colloidal Gold ◽  
Phosphotungstic Acid ◽  
Uranyl Acetate ◽  
Hantavirus Pulmonary Syndrome ◽  
Deer Mice ◽  
Immune Electron Microscopy ◽  
Negative Stain

An outbreak of unexplained acute pulmonary syndrome with high fatality was recognized in the spring of 1993 in the southwestern United States. The cause of the illness was quickly identified serologically and genetically as a hantavirus and the disease was named hantavirus pulmonary syndrome (HPS). Recently, the virus was isolated from deer mice which had been trapped near the homes of HPS patients, and cultivated in Vero E6 cells. We identified the cultivated virus by negative-stain direct and colloidal gold immune electron microscopy (EM).Virus was extracted, clarified, and concentrated from unfixed and 0.25% glutaraldehyde fixed supernatant fluids of infected Vero E6 cells by a procedure described previously. Concentrated virus suspensions tested by direct EM were applied to glow-discharge treated formvar-carbon filmed grids, blotted, and stained with 0.5% uranyl acetate (UA) or with 2% phosphotungstic acid (PTA) pH 6.5. Virus suspensions for immune colloidal gold identification were adsorbed similarly to filmed grids but incubated for 1 hr on drops of 1:50 diluted monoclonal antibody to Prospect Hill virus nucleoprotein or with 1:50 diluted sera from HPS virus infected deer mice.

Potent Chitin Synthase Inhibitors from Plants

2020 ◽  
Vol 16 (1) ◽  
pp. 58-63
Author(s):  
Amrutha Vijayakumar ◽  
Ajith Madhavan ◽  
Chinchu Bose ◽  
Pandurangan Nanjan ◽  
Sindhu S. Kokkal ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Caenorhabditis Elegans ◽  
Aspergillus Niger ◽  
Small Molecules ◽  
Tip Growth ◽  
Chitin Synthase ◽  
Chitin Synthesis ◽  
Hyphal Tip Growth ◽  
Hyphal Tip

Background: Chitin is the main component of fungal, protozoan and helminth cell wall. They help to maintain the structural and functional characteristics of these organisms. The chitin wall is dynamic and is repaired, rearranged and synthesized as the cells develop. Active synthesis can be noticed during cytokinesis, laying of primary septum, maintenance of lateral cell wall integrity and hyphal tip growth. Chitin synthesis involves coordinated action of two enzymes namely, chitin synthase (that lays new cell wall) and chitinase (that removes the older ones). Since chitin synthase is conserved in different eukaryotic microorganisms that can be a ‘soft target’ for inhibition with small molecules. When chitin synthase is inhibited, it leads to the loss of viability of cells owing to the self- disruption of the cell wall by existing chitinase. Methods: In the described study, small molecules from plant sources were screened for their ability to interfere with hyphal tip growth, by employing Hyphal Tip Burst assay (HTB). Aspergillus niger was used as the model organism. The specific role of these small molecules in interfering with chitin synthesis was established with an in-vitro method. The enzyme required was isolated from Aspergillus niger and its activity was deduced through a novel method involving non-radioactively labelled substrate. The activity of the potential lead molecules were also checked against Candida albicans and Caenorhabditis elegans. The latter was adopted as a surrogate for the pathogenic helminths as it shares similarity with regard to cell wall structure and biochemistry. Moreover, it is widely studied and the methodologies are well established. Results: Out of the 11 compounds and extracts screened, 8 were found to be prospective. They were also found to be effective against Candida albicans and Caenorhabditis elegans. Conclusion: Purified Methyl Ethyl Ketone (MEK) Fraction1 (F1) of Coconut (Cocos nucifera) Shell Extract (COSE) was found to be more effective against Candida albicans with an IC50 value of 3.04 μg/mL and on L4 stage of Caenorhabditis elegans with an IC50 of 77.8 μg/mL.

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