Wild beets as an important inoculum source of Alternaria alternata, a cause of leaf blight of cotton in Israel

1991 ◽  
Vol 69 (12) ◽  
pp. 2608-2615 ◽  
Author(s):  
Yoav Bashan ◽  
Hanna Levanony ◽  
Reuven Or
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Relative Humidity ◽  
Alternaria Alternata ◽  
Growing Season ◽  
Virulent Isolate ◽  
Leaf Tissues ◽  
Wild Beet ◽  
Overwintering Survival ◽  
Scanning Electron

Alternaria alternata, isolated from the leaves of wild beets, infected cotton as well as wild and cultivated beets. Scanning electron microscopy of wild beet and cotton leaves infected by an aggressive isolate of A. alternata revealed that conidiophores of the pathogen emerged only from necrotic areas of leaf tissues. Sporulation occurred on leaves only during periods of high relative humidity (> 95%) and temperatures ranging from 20 to 28 °C. Under low relative humidity (60% at 22–25 °C), mycelium penetrated into internal tissues of the leaf or emerged through the stomata. A less virulent isolate did not develop surface mycelium on inoculated leaves, but sporulation was detected on the leaf veins. Plants in several cotton fields adjacent to the diseased wild beet plants were infected by the pathogen early in the growing season. This study proposes that isolates of A. alternata that are virulent on cotton may overwinter on wild beet plants, making them an important source of the pathogen inoculum in epidemics of alternaria blight of cotton. Key words: Alternaria, beet, cotton diseases, fungi overseason transfer, fungi overwintering, survival.

Detection of allergens from Alternaria alternata by gold-conjugated anti-human IgE and field emission scanning electron microscopy

2006 ◽  
Vol 316 (1-2) ◽  
pp. 167-170 ◽  
Author(s):  
Jason K. Sercombe ◽  
Wijnand Eduard ◽  
Tony C. Romeo ◽  
Brett J. Green ◽  
Euan R. Tovey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Alternaria Alternata ◽  
Scanning Electron

Characteristics and Release Behavior of Sodium Alginate Microencapsulation Containing Cinnamon Oil

2010 ◽  
Vol 152-153 ◽  
pp. 508-511 ◽  
Author(s):  
Xi Hong Li ◽  
Juan Yun ◽  
Ya Ge Xing ◽  
Chang Liu ◽  
Qing Lian Xu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Relative Humidity ◽  
Core Material ◽  
Release Behavior ◽  
Cinnamon Oil ◽  
Mean Diameter ◽  
The Mean ◽  
The Stability ◽  
Scanning Electron

Microencapsulation technology is widely used in many industries recently because the stability of core material can be improved and the release characteristics can be modified. In this investigation, cinnamon oil was microencapsulated by simple coacervation. The size distribution is narrow and the mean diameter is 53.79 μm. The surface morphology of the resultant microcapsules was also characterized scanning electron microscopy (SEM). The results showed that the rates of cinnamon oil released from microencapsulation were not only affected by relative humidity in the microenvironment around microencapsulated powder, but also affected by the temperature.

Environmental Scanning Electron Microscopy as a Tool to Study Shrinkage Microcracks in Cement-Based Materials

1999 ◽  
Vol 589 ◽  
Author(s):  
J. Bisschop ◽  
J.G.M. Van Mier
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Relative Humidity ◽  
Cross Sections ◽  
Preparation Method ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Sample Preparation Method ◽  
Cement Based Materials ◽  
Scanning Electron

AbstractIn this paper a method is described to observe shrinkage microcracks on ‘wet’ specimen cross-sections of cement-based materials with Environmental Scanning Electron Microscopy (ESEM). A sample cooling device which can be used in the ESEM chamber was built to control the relative humidity above a microscope sample. The accuracy of measuring relative humidity is determined to be 5% at a sample temperature of 3°C. A microscope sample preparation method and a pump-down sequence of the ESEM-chamber, both without any drying of the sample, are described. Preliminary results show that in the studied mortar the visibility of shrinkage microcracks on a ‘wet’ specimen cross-section is low due to closure of microcracks by swelling of the cement paste.

Reduced Seed Germination after Pappus Removal in the North American Dandelion (Taraxacum officinale; Asteraceae)

Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 420-425 ◽  
Author(s):  
Alison N. Hale ◽  
Samantha M. Imfeld ◽  
Chloé E. Hart ◽  
Kevin M. Gribbins ◽  
Jay A. Yoder ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Relative Humidity ◽  
North American ◽  
Taraxacum Officinale ◽  
Water Entry ◽  
Laboratory Rearing ◽  
The North ◽  
Fungal Association ◽  
Scanning Electron

This study examined seed ultrastructure in relation to germination of North American dandelion seeds. Based on laboratory rearing observations, it was thought that the design of the pappus acts as a conduit facilitating water entry into the seed. It was hypothesized that seeds without a pappus would yield fewer seedlings and require more time to germinate than seeds with an intact pappus. Seed ultrastructure was investigated using scanning electron microscopy, while relative humidity and fungal association were explored as factors that may confer an advantage to intact seeds. Results indicate that germination for seeds lacking a pappus is 31% lower than control seeds (with an intact pappus) and that the seeds lacking a pappus require more time to germinate. Relative humidity did not differentially affect germination, and while a fungus Cladosporium cladosporioides was recovered internally, its presence neither enhanced germination nor decreased time to germination when tested by antimycotic removal. Electron micrographs revealed that (1) the pappus is hollow and (2) the pericarp of the fruit fuses with and partially encloses the pappus. Fusion of the pappus with the fruit suggests that this structure acts as a device to regulate seed hydration.

scholarly journals Necrotrophic fungi associated with epidermal microcracking caused by chilling injury in pickling cucumber fruit

2007 ◽  
Vol 42 (4) ◽  
pp. 593-598 ◽  
Author(s):  
Juan Antonio Martínez ◽  
Juan Pablo Fernández-Trujillo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Alternaria Alternata ◽  
Chilling Injury ◽  
Cucumis Sativus L ◽  
Surface Cracking ◽  
Pickling Cucumber ◽  
Necrotrophic Fungi ◽  
Cucumber Fruit ◽  
Scanning Electron

The objective of this work was to visualize the association between microcracking and other epidermal chilling injury symptoms, and to identify rots in cucumber fruit (Cucumis sativus L.) by scanning electron microscopy (SEM). Depressed epidermal areas and surface cracking due to damages of subepidermal cells characterized the onset of pitting in cucumber fruit. The germination of conidia of Alternaria alternata, with some of them evident on the fractures in the cultivar Trópico, occurred after damaging on the epidermis. Before, the chilling injury symptoms became visible, Stemphylium herbarum conidia germinated, and mycelium penetrated through the hypodermis using the microcracks as pathway. In the cultivar Perichán 121 the fungus was identified as Botrytis cinerea.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

Spontaneous Cataract in Nude Athymic Mice

1977 ◽  
Vol 35 ◽  
pp. 512-513
Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nude Mouse ◽  
Cellular Immunity ◽  
Phosphate Buffer ◽  
Osmium Tetroxide ◽  
Athymic Mice ◽  
Transmission Microscopy ◽  
Mouse Lens ◽  
Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

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