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.

Free-living marine planktonic unarmoured dinoflagellates from the Gulf of Mexico and the Mexican Pacific

2015 ◽  
Vol 58 (1) ◽  
Author(s):  
Sergio Escobar-Morales ◽  
David U. Hernández-Becerril
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gulf Of Mexico ◽  
Species Composition ◽  
New Records ◽  
Morphological Characters ◽  
Phylogenetic Group ◽  
Free Living ◽  
Mexican Pacific ◽  
Scanning Electron

AbstractThe so-called unarmoured dinoflagellates are not a “natural” (phylogenetic) group but they lack thecal plates, share fragility and possess relatively few morphological characters that can be positively identified. This study depicts the species composition of unarmoured dinoflagellates collected from sites along the coasts of the Gulf of Mexico and the Mexican Pacific and includes their descriptions and illustrations. We identified a total of 25 species belonging to 13 genera and six families that were studied through various techniques using light and scanning electron microscopy. Seven new records for the Mexican Pacific are annotated here that include

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 3D Bioprintability of Konjac Glucomannan Hydrogel

2019 ◽  
Vol 26 (1) ◽  
pp. 109-113
Author(s):  
Yulong WANG ◽  
Lu HAN ◽  
Jia YAN ◽  
Kun HU ◽  
Luhai LI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Loss Modulus ◽  
High Viscosity ◽  
Konjac Glucomannan ◽  
Potential Applications ◽  
Scaffold Materials ◽  
Konjac Gum ◽  
Water Holding ◽  
Scanning Electron

Konjac glucomannan has potential applications in bio-printing, due to its unique properties, such as high viscosity, water-holding capacity and easy gelatinization. In this study, the rheological properties, i.e. the viscosity with changing the shear rate and the storage modulus G’ and loss modulus G’’ curve, of different concentrations of konjac gum hydrogel, were thoroughly measured. Furthermore, the pore sizes of various concentrated konjac gum hydrogel were observed under scanning electron microscopy (SEM). The bio-printability of konjac gum hydrogel was thoroughly evaluated using piston-type 3D bio-printer. It was showed that, 7% konjac gum hydrogel demonstrated the best bio-printability, which has potentially applied as scaffold materials in bio-printing field.

scholarly journals Comparison of techniques for counting prokaryotes in marine planktonic and biofilm samples

2021 ◽  
Vol 85 (3) ◽  
pp. 211-220
Author(s):  
Vanessa Ochi Agostini ◽  
Letícia Terres Rodrigues ◽  
Alexandre José Macedo ◽  
Erik Muxagata
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Damage ◽  
High Variability ◽  
Epifluorescence Microscopy ◽  
Free Living ◽  
Marine Biofilm ◽  
Comparison Of Techniques ◽  
Green Fluorescent ◽  
Scanning Electron

Though a large number of techniques are available for the study of aquatic bacteria, the aim of this study was to establish a technique for analysing free-living and biofilm prokaryotic cells through laboratory assays. In particular, we wished to analyse the efficiency of ultrasound to detach and disrupt biofilm, to obtain an efficient stain treatment for quantifying free-living and biofilm prokaryotes in flow cytometry (FC), and to compare epifluorescence microscopy (EFM), scanning electron microscopy (SEM) and FC for quantifying free-living and biofilm prokaryotes#. Marine-grade plywood substrates were immersed in natural marine water that was conditioned for 12 days. At 6 and 12 days, water aliquots and substrates were removed to estimate free-living and biofilm prokaryote density. Ultrasound efficiently removed marine biofilm from substrates (up to 94%) without cell damage. FC analysis (unstained) reliably quantified marine plankton and young or mature biofilm prokaryotes compared with other staining (acridine orange, 4′,6-diamidino-2-phenylindole, propidium iodide and green fluorescent nucleic acid), EFM or SEM techniques. FC and SEM achieved similar results, while a high variability was observed in the EFM technique. FC was faster and more precise than SEM because the count is not dependent on the observer.

Scanning Electron Microscopy of Trophozoites of Naegleria Species

1985 ◽  
Vol 43 ◽  
pp. 642-643
Author(s):  
M. Lattyak ◽  
G. Cabral ◽  
F. Marciano-Cabral
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Membrane Surface ◽  
Opportunistic Pathogens ◽  
Environmental Isolates ◽  
Free Living ◽  
Naegleria Lovaniensis ◽  
Primary Amebic Meningoencephalitis ◽  
Scanning Electron ◽  
Naegleria Gruberi

The genus, Naegleria, includes four species of amebae which are either free-living or opportunistic pathogens. Naegleria fowleri, is the causative agent of Primary Amebic Meningoencephalitis, a rare but almost always fatal disease in man. Naegleria australiensis is an environmental isolate which is moderately pathogenic in mice. Naegleria lovaniensis and Naegleria gruberi are nonpathogenic environmental isolates. The four species were examined by scanning electron microscopy in order to determine whether membrane surface extensions, called food cups, could be correlated to pathogenicity. Food cups have been previously identified on the surface of Entamoeba histolytica and N. fowleri. It has been suggested that the food cups or stomas, are associated with internationalization of liquid and particulate components.

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).

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