Ornamentation types of conidia and conidiogenous structures in fasciculate Penicillium species using scanning electron microscopy

KOZAKIEWICZ, Z., 1988. Ornamentation types of conidia and conidiogenous structures in fasciculate Penicillium species using scanning electron microscopy. As part of a multidisciplinary approach to the taxonomy of the fasciculate Penicillium species, the conidial ornamentation of 320 strains was examined in order to determine the types and range of ornamentation and assess the stability of this feature as a taxonomic character.
Five conidial ornamentation classes were identified: echinulate, tuberculate, reticulate, microtuberculate and microverrucate. The technique of cryoscanning was used for examining the penicillus, and assessing such characters as roughening, shape and orientation of the branches. The method provides a fast means of examining freshly frozen material in the absence of artefacts associated with air-drying, freezing and critical-point drying techniques.
Studies on large numbers of conidia from the same isolate and from isolates referred to the same species showed the scanning electron microscopy results to be reproducible and provide an objective and accurate method for comparing micromorphological features. The ornamentation types can be of particular value in species identification.     

Scanning electron microscopy of the conidia produced by the mycelial form of Paracoccidioides brasiliensis

The conidia produced by the mycelial form of Paracoccidioides brasiliensis were examined by scanning electron microscopy for the first time. Several different conidial types were characterized. These included intercalary arthroconidia, several types of septate conidia that are formed from other conidia, pedunculate conidia, and terminal hyphal conidia. In addition, the ultrastructure of the supporting pedestal of the pedunculate conidium was found to be separated from the mother conidium by a septum in some instances, and at other times it was not.     

Scanning electron microscopy of barley protoplasts

Summary Scanning electron micrographs of barley protoplasts were compared using various preparatory techniques. Numerous features were observed which turned out to be artifactual characteristics of the processing procedure used in collecting and dehydrating the samples. The most successful technique gave protoplasts which presumably maintained their natural structural integrity, as judged by retention of sphericity and absence of holes in the plasma membrane. The relative numbers of fragmented protoplasts and cellular organelles was also greatly reduced.     

Scanning electron microscopy of vaginal colonization

Changes in the appearance of the vaginal epithelium of rats during the estrous cycle were seen by scanning electron microscopy. Bacterial colonization of this tissue appeared to be influenced by these changes.     

Scanning electron microscopy of experimental adiaspiromycosis

Adiaspiromycotic granulomas of mice experimentally inoculated with fungusEmmonsia crescens Emmons et Jellison 1960 were examined by scanning electron microscopy. Their morphology, surface structures, and germinating adiaspores isolated from granulomas are described.     

Scanning electron microscopy of echinoid podia

Summary Tube feet of the sea urchin Strongylocentrotus franciscanus were studied with the scanning electron microscope (SEM). By use of fractured preparations it was possible to obtain views of all components of the layered tube-foot wall.The outer epithelium was found to bear tufts of cilia possibly belonging to sensory cells. The nerve plexus was clearly revealed as being composed of bundles of varicose axons. The basal lamina, which covers the outer and inner surfaces of the connective tissue layer, was found to be a mechanically resistant and elastic membrane. The connective tissue appears as dense bundles of (collagen) fibers. The luminal epithelium (coelothelium) is a single layer of flagellated collar cells.There is no indication that the muscle fibers, which insert on the inner basal lamina of the connective tissue layer are innervated by axons from the basiepithelial nerve plexus.The results agree with previous conclusions concerning tube-foot structure based on transmission electron microscopy, and provide additional information, particularly with regard to the outer and inner epithelia.This investigation was supported by the Sonderforschungsbereich 138 of the Deutsche Forschungsgemeinschaft. The work was carried out at the Friday Harbor Laboratories of the University of Washington. The authors are indebted to the Director, Professor A.O.D. Willows for use of the facilities, and to Drs. Christopher Reed and Tom Schroeder for invaluable instruction and assistance     

Scanning electron microscopy of chloroplast ultrastructure

A range of fracturing and sectioning techniques are now available which permit intracellular structures to be observed in the scanning electron microscope. One such technique, based on the method of Tanaka (1981), has been used to study chloroplast ultrastructure in Japan laurel, Aucuba japonica. Small pieces of leaves were fixed, fractured whilst frozen and transferred to a dilute solution of osmium tetroxide in which cytoplasmic maceration took place. Specimens were dehydrated, critical point dried and examined was required to remove the stroma from fractured chloroplasts. Following this treatment details of the chloroplast envelope, frets, grana and plastoglobuli could be observed. The results were compared with conventionally prepared thin sections examined in the transmission electron microscope and with the three dimensional reconstructions described in the literature.