Ultrastructure of stromatal anamorphs in the Sclerotiniaceae

1989 ◽  
Vol 67 (2) ◽  
pp. 394-406 ◽  
Author(s):  
Linda M. Kohn ◽  
Douglas J. Grenville
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Monilinia Fructicola ◽  
Cellular Organization ◽  
Ultrastructural Studies ◽  
Sclerotium Cepivorum ◽  
Transmission Electron ◽  
Septal Pores

As part of comparative anatomical, histochemical, and ultrastructural studies of stromata in the Sclerotiniaceae, mature stromata produced in vitro by 11 species representing six genera and one form-genus were examined using transmission electron microscopy. Sclerotial-stromatal taxa were Sclerotinia sclerotiorum, S. trifoliorum, S. minor, Sclerotium cepivorum, Botrytis cinerea, B. porri, Monilinia fructicola, and Myriosclerotinia borealis. Substratal-stromatal taxa were Sclerotinia homoeo-carpa, Rutstroemia sydowiana, and Lambertella subrenispora. Three types of rind were observed: a living cellular rind, a dead cellular rind, and a stromatal rind. Sclerotial species were distinguished from stromatal species not only by the rind type, but also by the confluent extracellular matrix around cortical and medullary cell walls. Presence of lacunae in this matrix distinguished Sclerotinia spp. and M. borealis from Botrytis spp. and Monilinia fructicola. Rind, cortical, and medullary cells contained abundant storage vacuoles in most taxa. The distribution and proportion of organelles to storage vacuoles differed among taxa. Plugged septal pores with associated Woronin bodies were similar among the taxa where they were observed. Sclerotia of Sclerotium cepivorum, which has no known teleomorph, are ultrastructurally most like sclerotia of Sclerotinia or Botrytis anamorphs of Botryotinia species. Substratal stromata of S. homoeocarpa showed unusually complex cellular organization. Sclerotial stromata of M. fructicola contained unusual storage vacuoles with heterogeneous contents.

Morphometrical Ultrastructural Studies of the Rat's Hepatocytes Under Cooling

1997 ◽  
Vol 3 (S2) ◽  
pp. 245-246
Author(s):  
A.S. Kaprelyants ◽  
A.A. Kaprelyants ◽  
A.N. Reylan ◽  
R.K. Migunova
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscopic ◽  
Rat Hepatocyte ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Morphometric Methods

The aim of given investigation is to study the effect of cooling upon rat hepatocyte structure using transmission electron microscopic and computer morphometric methods. Ultrastructural and morphometrical characteristics of hepatocytes under liver cooling for various levels under in vivo and in vitro conditions were investigated. Vistar rats of 180-250 g were used in the experiment. Liver cooling (in vivo) was performed by means of original cryoapplicator with different probe temperature (1,2). Liver tissue for transmission electron microscopy was fixed in glutaraldehyde fixator on cocadylate buffer and OsO4. Dehydration was completed on acetone (3). Tissue embedding was done into the mixture of Epon/Araldite epoxy rasin. Ultrathin slices were contrasted by the method of Reinolds. Cell viewing and imaging were accomplished by electron microscope at accelerating power of 75kV.Morphometrical and stereometrical analysis was performed using the “Morpho-Tools” original computer system (c) 1994-1996 A.S. Kaprelyants, A.A. Kaprelyants, A.N. Reylan .

Ultrastructural studies on infection of sclerotia of Sclerotinia sclerotiorum by Talaromyces flavus

1989 ◽  
Vol 67 (7) ◽  
pp. 2199-2205 ◽  
Author(s):  
D. L. McLaren ◽  
H. C. Huang ◽  
S. R. Rimmer ◽  
E. G. Kokko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sclerotinia Sclerotiorum ◽  
Cell Walls ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Talaromyces Flavus

Talaromyces flavus is a destructive hyperparasite capable of infecting sclerotia of Sclerotinia sclerotiorum. Examinations of sclerotia by transmission electron microscopy at 3, 7, and 12 days after inoculation revealed that hyphae of T. flavus penetrated the rind cell walls directly. Etching of the cell walls at the penetration site was evident. This suggests that wall-lysing enzymes may be involved in the process of infection. Hyphae of T. flavus grew both intercellularly and intracellularly throughout the rind, cortical, and medullary tissues. Ramification of the hyperparasite in the sclerotium resulted in destruction and collapse of sclerotial tissues.

scholarly journals Adherence of Giardia lambliaTrophozoites to Int-407 Human Intestinal Cells

2001 ◽  
Vol 8 (2) ◽  
pp. 258-265 ◽  
Author(s):  
M. Céu Sousa ◽  
C. A. Gonçalves ◽  
V. A. Bairos ◽  
J. Poiares-da-Silva
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ventral Surface ◽  
Host Cells ◽  
Intestinal Cells ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Vitro Model

ABSTRACT Attachment of Giardia lamblia trophozoites to enterocytes is essential for colonization of the small intestine and is considered a prerequisite for parasite-induced enterocyte dysfunction and clinical disease. In this work, coincubation of Giardiawith Int-407 cells, was used as an in vitro model to study the role of cytoskeleton and surface lectins involved in the attachment of the parasite. This interaction was also studied by scanning and transmission electron microscopy. Adherence was dependent on temperature and was maximal at 37°C. It was reduced by 2.5 mM colchicine (57%), mebendazole (10 μg/ml) (59%), 100 mM glucose (26%), 100 mM mannose (22%), 40 mM mannose-6-phosphate (18%), and concanavalin A (100 μg/ml) (21%). No significant modification was observed when Giardia was pretreated with cytochalasins B and D and with EDTA. Giardia attachment was also diminished by preincubating Int-407 cells with cytochalasin B and D (5 μg/ml) (16%) and by glutaraldehyde fixation of intestinal cells and ofG. lamblia trophozoites (72 and 100%, respectively). Ultrastructural studies showed that Giardia attaches to the Int-407 monolayer predominantly by its ventral surface. Int-407 cells contact trophozoites with elongated microvilli, and both trophozoite imprints and interactions of Giardia flagella with intestinal cells were also observed. Transmission electron microscopy showed that Giardia lateral crest and ventrolateral flange were important structures in the adherence process. Our results suggest a combination of mechanical and hydrodynamic forces in trophozoite attachment; surface lectins also seem to mediate binding and may be involved in specific recognition of host cells.

scholarly journals Ultrastructural Studies of `Kensington' Mango (Mangifera indica Linn.) Heat Injuries

HortScience ◽  
1995 ◽  
Vol 30 (1) ◽  
pp. 102-103 ◽  
Author(s):  
Keryl K. Jacobi ◽  
Don Gowanlock
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Walls ◽  
Mangifera Indica ◽  
Hot Water ◽  
Hot Water Treatment ◽  
Mango Fruit ◽  
Ultrastructural Studies ◽  
Transmission Electron ◽  
Parenchyma Cells

Mature green `Kensington' mango fruit were submerged in hot water at 46C until the fruit center reached 45C and then held for 30 minutes. The fruit were allowed to ripen for 7 to 10 days after the hot water treatment, and then damaged areas of skin and mesocarp tissue were prepared for observation by scanning and transmission electron microscopy. Heating-related injuries included rupturing the patterned cuticle and exocarp and exposing the underlying cells and hollow cavities (which varied in size and shape) randomly distributed within the mesocarp beneath the skin. Starch deposits still were present in the mesocarp parenchyma cells. The cell walls of damaged mesocarp parenchyma cells were convoluted and thickened in places. The injury suggested disruption of enzymes involved in carbohydrate metabolism.

Maytansine-Induced Mitotic Arrest in Human Lymphoblasts

1977 ◽  
Vol 35 ◽  
pp. 460-461
Author(s):  
Tai-Te Chao ◽  
John Sullivan ◽  
Awtar Krishan
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
Transmission Electron Microscopy ◽  
Tubulin Polymerization ◽  
Vinca Alkaloids ◽  
Antimitotic Activity ◽  
Transmission Electron ◽  
Flow Microfluorometry ◽  
Brain Tubulin

Maytansine, a novel ansa macrolide (1), has potent anti-tumor and antimitotic activity (2, 3). It blocks cell cycle traverse in mitosis with resultant accumulation of metaphase cells (4). Inhibition of brain tubulin polymerization in vitro by maytansine has also been reported (3). The C-mitotic effect of this drug is similar to that of the well known Vinca- alkaloids, vinblastine and vincristine. This study was carried out to examine the effects of maytansine on the cell cycle traverse and the fine struc- I ture of human lymphoblasts.Log-phase cultures of CCRF-CEM human lymphoblasts were exposed to maytansine concentrations from 10-6 M to 10-10 M for 18 hrs. Aliquots of cells were removed for cell cycle analysis by flow microfluorometry (FMF) (5) and also processed for transmission electron microscopy (TEM). FMF analysis of cells treated with 10-8 M maytansine showed a reduction in the number of G1 cells and a corresponding build-up of cells with G2/M DNA content.

scholarly journals Ethosomes and Transethosomes for Mangiferin Transdermal Delivery

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 768
Author(s):  
Maddalena Sguizzato ◽  
Francesca Ferrara ◽  
Supandeep Singh Hallan ◽  
Anna Baldisserotto ◽  
Markus Drechsler ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radical Scavenging ◽  
Human Keratinocytes ◽  
Antioxidant Response ◽  
Correlation Spectroscopy ◽  
Inflammatory Status ◽  
Transmission Electron ◽  
Anti Inflammatory

Mangiferin is a natural glucosyl xanthone with antioxidant and anti-inflammatory activity, making it suitable for protection against cutaneous diseases. In this study ethosomes and transethosomes were designed as topical delivery systems for mangiferin. A preformulation study was conducted using different surfactants in association with phosphatidylcholine. Vesicle dimensional distribution was monitored by photon correlation spectroscopy, while antioxidant capacity and cytotoxicity were respectively assessed by free radical scavenging analysis and MTT on HaCaT keratinocytes. Selected nanosystems were further investigated by cryogenic transmission electron microscopy, while mangiferin entrapment capacity was evaluated by ultracentrifugation and HPLC. The diffusion kinetics of mangiferin from ethosomes and transethosomes evaluated by Franz cell was faster in the case of transethosomes. The suitability of mangiferin-containing nanovesicles in the treatment of skin disorders related to pollutants was investigated, evaluating, in vitro, the antioxidant and anti-inflammatory effect of ethosomes and transethosomes on human keratinocytes exposed to cigarette smoke as an oxidative and inflammatory challenger. The ability to induce an antioxidant response (HO-1) and anti-inflammatory status (IL-6 and NF-kB) was determined by RT-PCR and immunofluorescence. The data demonstrated the effectiveness of mangiferin loaded in nanosystems to protect cells from damage. Finally, to gain insight into the keratinocytes’ uptake of ethosome and transethosome, transmission electron microscopy analyses were conducted, showing that both nanosystems were able to pass intact within the cells.

scholarly journals Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

2010 ◽  
Vol 10 ◽  
pp. 879-893 ◽  
Author(s):  
Nathaniel G. N. Milton ◽  
J. Robin Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Islet Amyloid Polypeptide ◽  
Amyloid Β ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide ◽  
Transmission Electron

The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrilsin vitroandin vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KDof 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

Dipetalonema viteae: ultrastructural study on the in vitro interaction between rat macrophages and microfilariae in the presence of IgE antibody

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M. A. Ouaissi ◽  
A. Haque ◽  
A. Capron
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Peritoneal Macrophages ◽  
Immune Serum ◽  
Sequence Of Events ◽  
Transmission Electron ◽  
Dipetalonema Viteae ◽  
In Vitro Interaction

SUMMARYThe in vitro interaction between rat peritoneal macrophages and Dipetalonema viteae microfilariae in the presence of amicrofilaraemic rat immune serum was studied by transmission electron microscopy. The probable sequence of events leading to the killing of D. viteae microfilaria by macrophages is as follows. (a) Rat peritoneal macrophages in the presence of amicrofilaraemic rat immune serum adhere to the parasite surface, (b) the macrophages extend their pseudopodia around the parasite, (c) the ‘lysosome-like’ granules discharge their contents on to the parasite surface, (d) the lytic activity of these products begins at the parasite surface and (e) subsequent breaking of the microfilarial cuticle occurs, exposing the parasite intracellular material.

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