Nuclear behaviour accompanying ascus formation in Debaryomyces polymorphus

1987 ◽  
Vol 33 (11) ◽  
pp. 967-970 ◽  
Author(s):  
Sharon I. Forrest ◽  
Carl F. Robinow ◽  
Marc-André Lachance
Keyword(s):  
Light Microscopy ◽  
Cross Wall ◽  
Parent Cell ◽  
The Cross ◽  
Nuclear Behaviour ◽  
Debaryomyces Polymorphus

Nuclear behaviour in growing, dividing, and ascospore-forming cells of a strain of Debaryomyces polymorphus, a member of the "Torulaspora group" of yeasts, has been studied by light microscopy of fixed Giemsa-stained preparations. Many of the images seen were compatible with the suggestion, advanced by certain earlier students, that meiosis in this type of yeast is preceded by a process of self-diploidization involving the nucleus of a bud that, despite its small size, is already separated from the parent cell by a cross wall. Diploidization, in this view, is achieved by the return of the bud nucleus to the parent cell via a channel in the cross wall. The bud nucleus next fuses with the nucleus of the parent cell. Self-diploidization in D. polymorphus is thus achieved in the guise of heterogamous conjugation. This in turn is followed by meiosis. A lesser number of cell associations suggestive of isogamous conjugation has been encountered also.

scholarly journals Comparative Foliar Epidermal Studies in Coix lacryma-jobi L. andCoix aquatica Roxb. (Poaceae)

2009 ◽  
Vol 1 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Rinku Jitendrakumar DESAI ◽  
Vinay Madhukar RAOLE ◽  
Arun Omprakash ARYA
Keyword(s):  
Light Microscopy ◽  
Species Identification ◽  
Foliar Analysis ◽  
Abaxial Epidermis ◽  
Diagnostic Characters ◽  
Pointed Apex ◽  
Adaxial Epidermis ◽  
The Cross ◽  
Micromorphological Characters ◽  
Diagnostic Importance

As micromorphological knowledge was not available for Coix aquatica Roxb., the foliar epidermal studies were carried out for Coix lacryma-jobi L. and Coix aquatica Roxb. with the aim of determining the patterns of variation in their epidermal characteristics and assessing their value in species identification. Comparative foliar analysis was carried out by using light microscopy, after following routine scraping method. The characters of diagnostic importance in the identification of C. aquatica are the sparsely distributed prickle hairs with long pointed apex in the abaxial epidermis and dumbbell shaped silica cells in both the epidermises. The diagnostic characters for C. lacryma-jobi are the cross shaped silica cells and dumbbell shaped on the abaxial and adaxial epidermis respectively. The observed differences in certain micromorphological characters helps in identification of presently studied two species of Coix.

Schizolysis of dolipore–parenthesome septa in an arthroconidial fungus associated with Dendroctonus ponderosae and in similar anamorphic fungi

1993 ◽  
Vol 71 (8) ◽  
pp. 1032-1038 ◽  
Author(s):  
A. Tsuneda ◽  
S. Murakami ◽  
Lynne Sigler ◽  
Y. Hiratsuka
Keyword(s):  
Cell Separation ◽  
Mountain Pine Beetle ◽  
Dendroctonus Ponderosae ◽  
Cross Wall ◽  
Phlebia Radiata ◽  
The Cross ◽  
Group 2 ◽  
Complete Cell ◽  
Pupal Chamber ◽  
Group 1

An arthroconidial anamorphic fungus occurred in pupal chambers of the mountain pine beetle (Dendroctonus ponderosae) in lodgepole pine. No teleomorph was found and no suitable form genus was available for its disposition. However, in cultural characteristics it closely resembled the group 1 arthroconidial fungi, defined by other researchers as probable basidiomycete anamorphs. Septa of the pupal-chamber fungus and several of the group 1 isolates were of the dolipore–parenthesome type. Conidial separation was by septum schizolysis. Cell separation was initiated by disintegration of the dolipore wall, followed by progressive shrinkage of the fused dolipore wall. The parenthesomes retracted towards the dolipore wall and the triangular areas of the cross wall dissolved. The cross wall then split centripetally along the median electron-light layer to complete cell separation. The pupal-chamber fungus was also compared with Phlebia radiata (group 2) and with groups 3 and 4 strains of other researchers. Mauginiella scaettae was confirmed to have simple septa; thus this genus fails to accommodate arthroconidial basidiomycete anamorphs. Key words: basidiomycete anamorphs, dolipore–parenthesome septa, septum schizolysis, arthroconidiogenesis, Phlebia radiata, Mauginiella scaettae.

Fine structure of the septal pore apparatus in Polyporus tomentosus, Poria latemarginata, and Rhizoctonia solani

1972 ◽  
Vol 50 (12) ◽  
pp. 2559-2564 ◽  
Author(s):  
E. C. Setliff ◽  
W. L. MacDonald ◽  
R. F. Patton
Keyword(s):  
Fine Structure ◽  
Rhizoctonia Solani ◽  
Potassium Permanganate ◽  
Osmium Tetroxide ◽  
Cross Wall ◽  
Fixed Material ◽  
Pore Mouth ◽  
The Cross ◽  
Fibrillar Network

The septal pore apparatus was studied in Poria latemarginata, Polyporus tomentosus, and Rhizoctonia solani. Fixation by potassium permanganate was compared with fixation by glutaraldehyde – osmium tetroxide. Potassium permanganate reduced the size of the septal swelling about 50% and destroyed much of the internal integrity of the septal swelling. In glutaraldehyde – osmium tetroxide fixed material, a fibrillar network extended from the cross wall throughout the septal swelling. Except for this network, the septal swelling was electron transparent and similar in appearance to a vacuole. A rim of electronopaque material, attached to the septal swelling, surrounded the pore mouth in Polyporus tomentosus and Rhizoctonia solani.

Budding in Saccharomyces cerevisiae: Formation of the cross-wall

1977 ◽  
Vol 69 (3) ◽  
pp. 451-457 ◽  
Author(s):  
M. Victoria Elorza ◽  
G. Larriba ◽  
J.R. Villanueva ◽  
R. Sentandreu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cross Wall ◽  
The Cross

scholarly journals LytN, a Murein Hydrolase in the Cross-wall Compartment ofStaphylococcus aureus, Is Involved in Proper Bacterial Growth and Envelope Assembly

2011 ◽  
Vol 286 (37) ◽  
pp. 32593-32605 ◽  
Author(s):  
Matthew B. Frankel ◽  
Antoni P. A. Hendrickx ◽  
Dominique M. Missiakas ◽  
Olaf Schneewind
Keyword(s):  
Bacterial Growth ◽  
Cross Wall ◽  
Ofstaphylococcus Aureus ◽  
Murein Hydrolase ◽  
The Cross

scholarly journals Septal Secretion of Protein A inStaphylococcus aureusRequires SecA and Lipoteichoic Acid Synthesis

2018 ◽  
Author(s):  
Wenqi Yu ◽  
Dominique Missiakas ◽  
Olaf Schneewind
Keyword(s):  
Staphylococcus Aureus ◽  
Signal Peptide ◽  
Protein A ◽  
Lipoteichoic Acid ◽  
Acid Synthesis ◽  
Surface Proteins ◽  
Cross Wall ◽  
Staphylococcal Protein A ◽  
The Cross ◽  
Wall Depletion

AbstractSurface proteins ofStaphylococcus aureusare secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A signal peptide mutant defective for cleavage can be crosslinked to SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion ofsecDFdiminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and promotes precursor trafficking to peripheral membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.

scholarly journals Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Wenqi Yu ◽  
Dominique Missiakas ◽  
Olaf Schneewind
Keyword(s):  
Staphylococcus Aureus ◽  
Signal Peptide ◽  
Protein A ◽  
Lipoteichoic Acid ◽  
Acid Synthesis ◽  
Surface Proteins ◽  
Cross Wall ◽  
Staphylococcal Protein A ◽  
The Cross ◽  
Wall Depletion

Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and abolishes SpA precursor trafficking to septal membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.

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