scholarly journals Development of Colletotrichum acutatum in the foliar tissue of strawberry plants

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 429-431
Author(s):  
F.T. Arroyo ◽  
F.J. Moreno ◽  
P. Daza ◽  
J. Torreblanca ◽  
G. García-Herdugo ◽  
...  

Strawberry anthracnose, caused by Colletotrichum acutatum, is one of the most destructive disease of this crop throughout the world. Assymptomatic stages in the plant have been the aim of this work. Inoculated leaves samples were taken at different times and they were processed for scanner electron microscopy (SEM) and transmission electron microscopy (TEM). Conidial development on both surfaces leaves was determined. The ultrastructural study of fungus penetration into plant cell was characterized by the formation of vesicles over the fungus periphery and is a morphological parameter of the intense membranes traffic, also could be a evidence of a transcriptional activity and enzymatic cell secretion. Differences of symptoms on both surfaces of leaves were observed.

2010 ◽  
Vol 16 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Rossana C.N. Melo ◽  
Ann M. Dvorak ◽  
Peter F. Weller

AbstractMechanisms governing secretion of proteins underlie the biologic activities and functions of human eosinophils, leukocytes of the innate immune system, involved in allergic, inflammatory, and immunoregulatory responses. In response to varied stimuli, eosinophils are recruited from the circulation into inflammatory foci, where they modulate immune responses through the release of granule-derived products. Transmission electron microscopy (TEM) is the only technique that can clearly identify and distinguish between different modes of cell secretion. In this review, we highlight the advances in understanding mechanisms of eosinophil secretion, based on TEM findings, that have been made over the past years and that have provided unprecedented insights into the functional capabilities of these cells.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1304 ◽  
Author(s):  
Giulio Guzzinati ◽  
Thomas Altantzis ◽  
Maria Batuk ◽  
Annick De Backer ◽  
Gunnar Lumbeeck ◽  
...  

The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.


1998 ◽  
Vol 6 (9) ◽  
pp. 18-21
Author(s):  
Alwyn Eades

The world of electron microscopy is in a period of transition from acquiring images on film to acquiring images digitally, using CCD cameras, for example. It would be useful to knew how much information there is on a piece of film, in order to know how film compares with digital methods and to be able to make good judgements on the optimum moment to change from one technology to the other.This is an attempt to use simple arguments to estimate just how much information there is in an image exposed on film in the transmission electron microscope, the main reason for addressing this issue Is that, while many people are affected by it there seems to be little agreement on the answer.


1979 ◽  
Vol 204 (1156) ◽  
pp. 287-300 ◽  

C. simplex is a new species with an unusually wide geographical range, occurring at sea temperatures as varied as 0°C under ice at Pt Barrow or – 1°C in arctic Canada, to 22°C on the equator at the Galapagos Islands. The morphology and range of variation are illustrated by means of light microscopy, transmission electron microscopy and scanning electron microscopy applied to dry whole mounts prepared in situ from freshly-gathered wild material. Among the diagnostic structural features, special interest attaches to the position of the anterior transverse costa which is located unusually far back in comparison with other members of the genus; it is also shown to be within and not outside the ring of four longitudinal costae building up the lorica chamber, although this feature can only be ascertained by scanning. The differences between this species and C. natans (type species of the genus) are shown to be greater and to involve more characters than could previously have been recog­nized, and some possible functional implications are discussed in a preliminary way.


1975 ◽  
Vol 21 (11) ◽  
pp. 1661-1675 ◽  
Author(s):  
D. H. Ellis ◽  
D. A. Griffiths

Conidiogenesis in Torula herbarum and T. herbarum f. quaternella was observed by scanning and transmission electron microscopy. Conidia of the former were shown to be made up of three equally sized cells capped by a distinctive, and easily recognizable, conidiogenous cell. Conidiogenous cells also arose terminally on erect hyphae and on prostrate hyphae. The single-layered conidial cell walls were differentiated into an inner hyaline zone and an outer electron-dense zone formed by the deposition of melanin. Conidiogenous cells lacked melanin at the apex and, before conidiation, the lateral walls were strengthened by a further deposition of melanin. The apex bulged outwards and was modified into a new multicelled conidium bearing another apical conidiogenous cell. Continued development of new conidia resulted in an acropetal chain which became disarticulated after cytolysis within the conidiogenous cell. The relative distinctions between holoblastic and enteroblastic development are discussed and it is concluded that the conidia should be referred to as blastoconidia.


Author(s):  
J.A. Chandler ◽  
C.K. Chou

Water-borne copper-chrome-arsenate preservatives(CCA) are now recognised throughout the world as the most effective broad-spectrum preservatives and are extensively used today for a wider range of purposes than any other preservative type. The mode of action of this preservative against decaying fungi, however, is little known and this paper reports investigations into an understanding of the process of treatment. The combination of transmission electron microscopy and x-ray microanalysis has for the first time allowed an accurate location for analysis of the consistuent elements in this preservative when applied to wood.


1996 ◽  
Vol 4 (1) ◽  
pp. 24-27
Author(s):  
Alwyn Eades

The world of electron microscopy is in a period of transition from acquiring images on film to acquiring images digitally, using CCD cameras, for example. It would be useful to know how much information there is on a piece of film, in order to know how film compares with digital methods and to be able to make good judgements on the optimum moment to change from one technology to the other.This is an attempt to use simple arguments to estimate just how much information there is in an image exposed on film in the transmission electron microscope. The main reason for addressing this issue is that, while many people are affected by it, there seems to be little agreement on the answer.


Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 477 ◽  
Author(s):  
Vsevolod L. Popov ◽  
Robert B. Tesh ◽  
Scott C. Weaver ◽  
Nikos Vasilakis

Since the beginning of modern virology in the 1950s, transmission electron microscopy (TEM) has been an important and widely used technique for discovery, identification and characterization of new viruses. Using TEM, viruses can be differentiated by their ultrastructure: shape, size, intracellular location and for some viruses, by the ultrastructural cytopathic effects and/or specific structures forming in the host cell during their replication. Ultrastructural characteristics are usually sufficient for the identification of a virus to the family level. In this review, we summarize 25 years of experience in identification of novel viruses from the collection of the World Reference Center for Emerging Viruses and Arboviruses (WRCEVA).


Author(s):  
Chuang Liu ◽  
Yang Yang ◽  
Yuanzhu Gao ◽  
Chenguang Shen ◽  
Bin Ju ◽  
...  

AbstractSince December 2019, the outbreak of Coronavirus Disease 2019 (COVID-19) spread from Wuhan, China to the world, it has caused more than 87,000 diagnosed cases and more than 3,000 deaths globally. To fight against COVID-19, we carried out research for the near native SARS-CoV-2 and report here our preliminary results obtained. The pathogen of the COVID-19, the native SARS-CoV-2, was isolated, amplified and purified in a BSL-3 laboratory. The whole viral architecture of SARS-CoV-2 was examined by transmission electron microscopy (both negative staining and cryo-EM). We observed that the virion particles are roughly spherical or moderately pleiomorphic. Spikes have nail-like shape towards outside with a long body embedded in the envelope. The morphology of virion observed in our result indicates that the S protein of SARS-CoV-2 is in post-fusion state, with S1 disassociated. This state revealed by cryo-EM first time could provide an important information for the identification and relevant clinical research of this new coronavirus.


1993 ◽  
Vol 71 (7) ◽  
pp. 985-991 ◽  
Author(s):  
Marnel Mouton ◽  
Michael J. Wingfield

Conidium development was studied and compared in Sporendocladia bactrospora (thought to resemble Chalara spp.) and in Phialocephala virens. Techniques used in the study include bright field and fluorescence microscopy, as well as scanning and transmission electron microscopy. Sporendocladia bactrospora had cylindrical conidia produced in true chains from phialidic conidiogenous cells with long cylindrical collarettes. An area of wall building activity at the base of the conidiogenous cell was characterized by secretory vesicles indicating ring wall building development. In Phialocephala virens, conidia were formed by apical wall building and distinct periclinal thickening was evident. From this study it was possible to confirm the fact that Phialocephala s.l. can clearly be divided into two distinct groups on the basis of conidium development. Key words: apical wall building, conidiogenesis, Phialocephala, ring wall building, Sporendocladia.


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