scholarly journals Scanning Electron Microscopy of Spore Germination in Dictyostelium discoideum

1972 ◽  
Vol 112 (3) ◽  
pp. 1383-1386 ◽  
Author(s):  
R. P. George ◽  
R. M. Albrecht ◽  
K. B. Raper ◽  
I. B. Sachs ◽  
A. P. MacKenzie
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dictyostelium Discoideum ◽  
Spore Germination ◽  
Scanning Electron

Culmination in the slime mould Dictyostelium discoideum studied with a scanning electron microscope

Development ◽  
1976 ◽  
Vol 35 (2) ◽  
pp. 323-333
Author(s):  
D. J. Watts ◽  
T. E. Treffry
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dictyostelium Discoideum ◽  
Fruiting Body ◽  
Maximum Height ◽  
Slow Process ◽  
Fruiting Body Formation ◽  
Basal Disc ◽  
Body Formation ◽  
Scanning Electron

Myxamoebae of Dictyostelium discoideum were allowed to develop on cellulose acetate filters, and specimens taken at various stages of fruiting body formation were prepared for study by scanning electron microscopy. In the immature fruiting body where the mass of pre-spore cells has just been lifted off the substratum by the developing stalk, the pre-spore cells are irregular in shape and are similar in appearance to cells in aggregates at earlier stages of development. As the stalk lengthens, the pre-spore cells gradually separate from one another and become rounded and elongate, but mature spores are not visible until the fruiting body reaches its maximum height. It is concluded that, contrary to previous reports, spore maturation is a slow process and is not completed until the sorus becomes pigmented. The mature stalk is surrounded by a smooth cellulose sheath but this does not envelop the cells of the basal disc, which remain discrete. The fruiting body is enclosed in a slime sheath and this may be important in holding together the mass of spores.

Contribution à l'étude du Bayoud, fosariose du palmier-dattier. I. Étude du cultivar sensible Deglet-Nour

1990 ◽  
Vol 68 (10) ◽  
pp. 2054-2058 ◽  
Author(s):  
Béatrice Mathéron ◽  
Abdellatif Benbadis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fusarium Oxysporum ◽  
Spore Germination ◽  
Date Palm ◽  
Wilt Disease ◽  
Root Epidermis ◽  
Bordered Pits ◽  
Early Reaction ◽  
Scanning Electron

Date palm seedlings were inoculated at the two-leaf stage with Fusarium oxysporum f. sp. albedinis, the causal agent of Bayoud. Following spore germination, hyphae bore a bole through the walls of the root epidermis and penetrated into the cortical parenchyma. The fungus then grows inter- or intra-cellularly towards the central cylinder and enters the xylem vessels. There, it continues to grow towards the leaves. The progression from vessel to vessel is achieved through bordered pits. The cultivar Deglet-Nour, known for its susceptibility to this wilt disease, exhibited no early reaction to the presence of the parasite in its tissues. Key words: date palm, Fusarium oxysporum f. sp. albedinis, scanning electron microscopy.

Cytological studies on the infection of barley cultivars with known resistance genotypes by Rhynchosporium secalis

1990 ◽  
Vol 68 (9) ◽  
pp. 1953-1961 ◽  
Author(s):  
H. Lehnackers ◽  
W. Knogge
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spore Germination ◽  
Leaf Surface ◽  
Rhynchosporium Secalis ◽  
Susceptible Cultivar ◽  
Infection Cycle ◽  
Fungal Development ◽  
Barley Cultivars ◽  
Scanning Electron

Seven races of Rhynchosporium secalis were screened for their virulence on a variety of barley cultivars. Four races were identified as virulent on cultivar Atlas 46 (resistance loci Rrs1 and Rrs2) but virulent on the near-isogenic cultivar Atlas (Rrs2). For one of these races, US238.1, the fungal infection cycle was followed on the susceptible cultivar by means of light and scanning electron microscopy. From a comparative analysis of fungal development on the susceptible and resistant cultivars, two lines of plant defense emerged: (i) inhibition of spore germination on the leaf surface and (ii) prevention of the establishment of the subcuticular stroma. Investigations of the development of race US238.1 on different barley cultivars with and without Rrs1 and on F1 individuals from different crosses excluded involvement of Rrs1 in the inhibition of spore germination. Possible pathogenicity mechanisms are discussed. Key words: leaf scald, microscopy, plant resistance.

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.

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