Biomedical subjects

F Mariat

Publications and source records attributed to F Mariat.

At least 37 records · Page 2Linked to original sources

PubMed1975

Ultrastructural studies of the mycelium-to yeast transformation of Sporothrix schenckii.

Fine details of the internal and external morphology of the in vitro mycelial phase (MP) to yeastlike phase (YP) transition of the dimorphic fungal pathogen Sporothrix schenckii are shown in electron micrographs of ultrathin sections. Morphological transformation at the ultrastructural level was observed to occur by direct formation of budlike structures at the tips and along the hyphae and by oidial cell formation. Direct budding of yeast from conidiospores was not observed. Early transitional forms arising by direct blastic action from the MP possessed conspicuous electron-dense microfibrillar material at the outer limits of the cell wall. The electron density of this microfibrillar material was enhanced by staining with acidified dialyzed iron. It is believed that this extracellular material may be composed in part of an acid mucosubstance. No acid phosphatase activity was associated with this microfibrillar material. This substance was found to be a characteristic of the outer limits of the cell wall of the YP of S. schenckii. Oidial YP cell formation occurred later during the transition. The cell wall of the developing oidial YP transitional form arose from an inner layer of the converting hyphae. No consupicuous alterations of the cytoplasmic content of the parent MP cell was observed during MP-to-YP transition. It is suggested that the MP-to-YP transition of S. schenckii may be regulated by at least two mechanisms involving alterations of the biochemical and/or biophysical nature of the cell wall of the MP cell in response to the conversional stimuli.

Cell Wall↗

PubMed1975

[Ecology of Sporothrix schenckii and of Ceratocystis stenoceras in Corsica and Alsace, French provinces free of sporotrichosis].

The study was conducted in 2 French Provinces free of sporotrichosis. Of 40 samples (soil, plant fragments, . . .) taken from Corsica, 59 isolations were obtained. All of these contained S. schenckii type of growth. Of 30 retained for further study, 14 were later identified as Ceratocystis stenoceras. All 14 needed pyrimidine as a growth factor. They developed well at 37 degrees and gave a yeast-like growth in shaken medium at 35 degrees and 25 degrees. One of the strains was pathogenic to mice. From 422 small mammals trapped in Alsace 37 isolations were made which morphologically were identified as S. schenckii. From these 31 were identified as C. stenoceras. Six isolations were considered as S. schenckii. The presence of nature of C. stenoceras and S. scheckii is discussed. Both fungi were isolated from various materials collected in tropical areas where sporotrichosis is endemic but also in such temperate areas as Corsica and Alsace where the mycosis is non-existent.

Animals↗

PubMed1975

[Fatty acid composition of polar and neutral lipids of Sporothrix schenckii and Ceratocystis stenoceras].

The fatty acids contained in the neutral and polar lipids from Sprorthrix schenckii and Ceratocystis stenoceras and 3 mutants of the latter fungus were found to be identical. The major fatty acids were palmitic, oleic and linoleic. The fungi had similar quantitative composition especially the mutant strains and S. schenckii. This observation provides more data regarding the possible relationship between Ceratocystis and sporothrix.

Ascomycota↗

PubMed1975

Ultrastructural and electron cytochemical studies of Entomophthora coronata.

Aspects of the fine structure as well as electron cytochemical localization studies of certain hydrolytic enzymes were examined by electron microscopy of ultrathin sections of the vegatative hyphae and conidia of the phycomycetous fungus, Entomophthora coronata. This entomogenous fungal organism is of interest since it has been increasingly implicated as the etiologic agent of phycomycosis of man and animals. On thin section, hyphal cells were frequently observed with septa while the cytoplasm was multinucleate. The conidium was bound by a multilayered cell wall. The cytoplasm of ungerminated conidia characteristically contained large numbers of a class of cytoplasmic organelle found in loose aggregates with lipid storage bodies. Similar organelles were observed in the cytoplasm of hyphal cells from 7-day old cultures. This round to oval to slightly reniform structure was bound by a single limiting membrane and composed of an electron dense, slightly granular matrix without evidence of crystalloid formation. The limiting membrane of the lipid storage bodies was observed to be intimately associated with that of one or more of these microbody-like organelles. This intimate association of the two cytoplasmic organelles suggests that the microbody-like organelle may be involved in some manner with lipid metabolism during the life cycle of the fungus. Cautious interpretations of electron cytochemical localization studies suggested that lipase, nonspecific esterase, and possibly aryl sulfatase were associated with the microbody-like organelles. Neither peroxidatic nor acid phosphatase activity could be demonstrated with these organelles of the conidial cytoplasm.

Arylsulfatases↗

PubMed1974