scholarly journals Dictyostelium discoideum fruiting bodies observed by scanning electron microscopy.

1980 ◽  
Vol 141 (2) ◽  
pp. 956-958 ◽  
Author(s):  
Y Murata ◽  
T Ohnishi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dictyostelium Discoideum ◽  
Fruiting Bodies ◽  
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.

Scanning electron microscopy of perithecial development in a species of Phyllactinia on oak

1974 ◽  
Vol 52 (10) ◽  
pp. 2175-2179 ◽  
Author(s):  
James L. Harris ◽  
Ivan L. Roth
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Structure ◽  
Pathogenic Fungi ◽  
Plant Pathogenic Fungi ◽  
Fruiting Bodies ◽  
Scanning Electron ◽  
Study Development

A species of Phyllactinia on oak was examined by scanning electron microscopy. The naturally dried fungus was minimally manipulated in preparation for study. Development was followed by examining various stages from initial to mature perithecium. Immature perithecial appendages were found to be less rigid than those which had matured. The sticky apical mucilage droplet on the maturing perithecium was observed, but the penicillate cells that form the droplet were not easily seen. As the appendages dried they lifted the perithecium off the surrounding surface. Some perithecia were found that had overturned and adhered to the hyphae-covered leaf by means of the mucilage droplet. This study has resulted in visualization of Phyllactinia surface structure in more detail than heretofore reported. Other plant pathogenic fungi, especially those producing naturally dry mature fruiting bodies, should be amenable to study by this method.

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

The postfire recovery of rock-inhabiting algae, microfungi, and lichens

1992 ◽  
Vol 70 (2) ◽  
pp. 301-312 ◽  
Author(s):  
Jacob Garty
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Green Algae ◽  
Water Holding Capacity ◽  
Rock Surface ◽  
Fruiting Bodies ◽  
Free Living ◽  
Mountain Area ◽  
Water Holding ◽  
Scanning Electron

Despite numerous investigations on the re-establishment of epiphytic cryptogams, especially lichens, after forest fires, very little is known about the recolonization of burnt rocks by lithobiontic microorganisms after fire in the Mediterranean region. Reported herein are the results of a combined field observation and scanning electron microscopy study focusing on the connection between the microrelief of the rocks that was shaped during prefire periods and the recolonization of pioneer lithobiontic microorganisms after the fire. Scanning electron microscopy revealed that the burnt rock surfaces exhibit 10 kinds of weathering elements that include 9 kinds of cryptogamic imprints corroded by saxicolous (rock-inhabiting) unicellular green algae, free-living microfungi, and fruiting bodies or microgrooves of endolithic lichens during prefire periods. The total volume of several selected structural weathering elements formed by lithobiontic microorganisms during the prefire period was estimated relative to the possible contribution of these lithobionts to local pedogenesis. Considering that the specific weight of chalk is 2.6 g/cm3, the estimated amount of the rock material removed by small pits with a diameter of 0.01 mm formed by unicellular green algae during the prefire period can reach 3.06 kg/ha mountain area with 10% rock coverage, while the estimated amount of chalk rock material removed by pinhead holes with a diameter of 0.8 mm formed by fruiting bodies of endolithic lichens can reach 174 kg/ha with the same rock coverage. Water-holding capacity of empty pinhead holes and small pits on the rock surface in burnt areas was also estimated, and it is suggested that the water-holding capacity of empty small pits (d = 0.01 mm) formed by unicellular green algae on rock surface per hectare mountain area with 10% rock coverage can reach 1.18 L, whereas in case of pinhead holes (d = 0.8 mm) formed by fruiting bodies of endolithic lichens the water-holding capacity can reach 66.9 L/ha with the same rock coverage. Scanning electron microscopy revealed the presence of three different kinds of unicellular green algae, one free-living microfungus, two different species of endolithic lichens, two epilithic lichen species, and great numbers of lichen ascospores, fungal spores, and hyphae established postfire in pinhead holes and small pits produced by former microlithobionts inhabiting rocks during prefire periods. These microorganisms and diaspores were also present in ruts, shallow rock depressions, and microcrevices produced by abiotic factors. Key words: lithobiontic microorganisms, wildfire, algae, microfungi, lichens.

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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