Similarities between nonsporulated yeast cells and asci

1974 ◽  
Vol 20 (11) ◽  
pp. 1615-1616
Author(s):  
S. D. Steele ◽  
J. J. Miller
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Yeast Cells ◽  
Sporulation Medium ◽  
Vegetative Cells

Yeast cells which did not sporulate in sporulation medium underwent some marked structural changes. Numerous vacuoles filled with material, possibly lipid, accumulated in the cytoplasm; the cell wall thickened and differentiated into an outer fibrillar and an inner particulate zone. The nonsporulated cells were viable but required 4–6 h at 27° to produce buds. In these respects the nonsporulated cells resembled asci or ascospores rather than vegetative cells.

GLYCOPEPTIDE SYNTHESIS DURING SPORULATION OF BACILLUS MEGATERIUM

1967 ◽  
Vol 13 (12) ◽  
pp. 1615-1620 ◽  
Author(s):  
William E. Gledhill
Keyword(s):  
Cell Wall ◽  
Stationary Phase ◽  
Bacillus Megaterium ◽  
Wall Material ◽  
Amino Sugars ◽  
Sporulation Medium ◽  
Cell Wall Material ◽  
Early Stationary Phase ◽  
Vegetative Cells ◽  
Number Of Cells

The present study was initiated to determine the amount of glycopeptide synthesized during sporulation of Bacillus megaterium. The glycopeptide fraction was isolated quantitatively from vegetative cells, sporulated cells, and free spores, and then assayed for amino sugars. The yields of glycopeptide hexosamine (GPH) in these preparations were compared on the basis of number of cells. During the early stationary phase of cultural growth, cells continued to synthesize cell wall material even though they did not divide or increase in size significantly. In the sporulation medium GPH synthesis was synchronized with the development of the endospore within the bacilli. During this period GPH formation occurred at an increased rate. Synthesis terminated as free spores were liberated from their sporangia. The total amount of GPH synthesized in the sporulating bacilli could be accounted for in the cleaned, free spores.

Li+ effect on the cell wall of the yeast Saccharomyces cerevisiae as probed by FT-IR spectroscopy

2013 ◽  
Vol 8 (8) ◽  
pp. 724-729 ◽  
Author(s):  
Aurelijus Zimkus ◽  
Audrius Misiūnas ◽  
Larisa Chaustova
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Ir Spectroscopy ◽  
Absorption Band ◽  
Structural Changes ◽  
Yeast Cells ◽  
Wall Structure ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

AbstractThe effect of Li+ ions as a transformation inducing agent on the yeast cell wall has been studied. Two Saccharomyces cerevisiae strains, p63-DC5 with a native cell wall, and strain XCY42-30D(mnn1) which contains structural changes in the mannan-protein complex, were used. Fourier transform infrared (FT-IR) spectroscopy has been used for the characterization of the yeast strains and for determination of the effect of lithium cations on the cell wall. A comparison of the carbohydrate absorption band positions in the 970–1185 cm−1 range, of Na+ and Li+ treated yeast cells has been estimated. Absorption band positions of the cell wall carbohydrates of p63-DC5 were not influenced by the studied ions. On the contrary, the treatment of XCY42-30D(mnn1) cells with Li+ ions shifted glucan band positions, implying that the cell wall structure of strain XCY42-30D(mnn1) is more sensitive to Li+ ion treatment.

scholarly journals Valorization of sugarcane bagasse by chemical pretreatment and enzyme mediated deconstruction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vihang S. Thite ◽  
Anuradha S. Nerurkar
Keyword(s):  
Cell Wall ◽  
Sugarcane Bagasse ◽  
Structural Changes ◽  
Enzymatic Saccharification ◽  
Dry Weight ◽  
Gravimetric Analysis ◽  
Chemical Pretreatment ◽  
Cell Wall Degrading Enzymes ◽  
First Time ◽  
Soluble Components

Abstract After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane bagasse (SCB). Filtrate analysis after NaOH, NH4OH and H2SO4 pretreatments yielded release of soluble reducing sugars (SRS) in range of ~0.17–0.44%, ~0.38–0.75% and ~2.9–8.4% respectively. Gravimetric analysis of pretreated SCB (PSCB) biomass also revealed dry weight loss in range of ~25.8–44.8%, ~11.1–16.0% and ~28.3–38.0% by the three pretreatments in the same order. Release of soluble components other than SRS, majorly reported to be soluble lignins, were observed highest for NaOH followed by H2SO4 and NH4OH pretreatments. Decrease or absence of peaks attributed to lignin and loosened fibrous appearance of biomass during FTIR and SEM studies respectively further corroborated with our observations of lignin removal. Application of commercial cellulase increased raw SCB saccharification from 1.93% to 38.84%, 25.56% and 9.61% after NaOH, H2SO4 and NH4OH pretreatments. Structural changes brought by cell wall degrading enzymes were first time shown visually confirming the cell wall disintegration under brightfield, darkfield and fluorescence microscopy. The microscopic evidence and saccharification results proved that the chemical treatment valorized the SCB by making it amenable for enzymatic saccharification.

New insights on Laminaria digitata ultrastructure through combined conventional chemical fixation and cryofixation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christos Katsaros ◽  
Sophie Le Panse ◽  
Gillian Milne ◽  
Carl J. Carrano ◽  
Frithjof Christian Küpper
Keyword(s):  
Cell Wall ◽  
General Structure ◽  
Raw Material ◽  
Rocky Shores ◽  
Chemical Fixation ◽  
Laminaria Digitata ◽  
Vegetative Cells ◽  
Biological Studies ◽  
New Findings ◽  
Wide Range

Abstract The objective of the present study is to examine the fine structure of vegetative cells of Laminaria digitata using both chemical fixation and cryofixation. Laminaria digitata was chosen due to its importance as a model organism in a wide range of biological studies, as a keystone species on rocky shores of the North Atlantic, its use of iodide as a unique inorganic antioxidant, and its significance as a raw material for the production of alginate. Details of the fine structural features of vegetative cells are described, with particular emphasis on the differences between the two methods used, i.e. conventional chemical fixation and freeze-fixation. The general structure of the cells was similar to that already described, with minor differences between the different cell types. An intense activity of the Golgi system was found associated with the thick external cell wall, with large dictyosomes from which numerous vesicles and cisternae are released. An interesting type of cisternae was found in the cryofixed material, which was not visible with the chemical fixation. These are elongated structures, in sections appearing tubule-like, close to the external cell wall or to young internal walls. An increased number of these structures was observed near the plasmodesmata of the pit fields. They are similar to the “flat cisternae” found associated with the forming cytokinetic diaphragm of brown algae. Their possible role is discussed. The new findings of this work underline the importance of such combined studies which reveal new data not known until now using the old conventional methods. The main conclusion of the present study is that cryofixation is the method of choice for studying Laminaria cytology by transmission electron microscopy.

Cell Wall Permeability of Pinto Bean Cotyledon Cells Regulates In Vitro Fecal Fermentation and Gut Microbiota

2021 ◽  
Author(s):  
Yanrong Huang ◽  
Sushil Dhital ◽  
Feitong Liu ◽  
Xiong Fu ◽  
Qiang Huang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Microbiota Composition ◽  
Colonic Fermentation ◽  
Pinto Bean ◽  
Wall Permeability ◽  
Cell Wall Permeability ◽  
Cotyledon Cells ◽  
Whole Foods

Processing induced structural changes of whole foods on regulation of colonic fermentation rate and microbiota composition are least understood and often overlooked. In the present study, intact cotyledon cells from...

scholarly journals Aspergillus nidulans wetA activates spore-specific gene expression.

1991 ◽  
Vol 11 (1) ◽  
pp. 55-62 ◽  
Author(s):  
M A Marshall ◽  
W E Timberlake
Keyword(s):  
Gene Expression ◽  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Gene Activation ◽  
Regulatory Function ◽  
Specific Gene ◽  
Coding Region ◽  
Vegetative Cells ◽  
Mutant Strains ◽  
Late Stages

The Aspergillus nidulans wetA gene is required for synthesis of cell wall layers that make asexual spores (conidia) impermeable. In wetA mutant strains, conidia take up water and autolyze rather than undergoing the final stages of maturation. wetA is activated during conidiogenesis by sequential expression of the brlA and abaA regulatory genes. To determine whether wetA regulates expression of other sporulation-specific genes, its coding region was fused to a nutritionally regulated promoter that permits gene activation in vegetative cells (hyphae) under conditions that suppress conidiation. Expression of wetA in hyphae inhibited growth and caused excessive branching. It did not lead to activation of brlA or abaA but did cause accumulation of transcripts from genes that are normally expressed specifically during the late stages of conidiation and whose mRNAs are stored in mature spores. Thus, wetA directly or indirectly regulates expression of some spore-specific genes. At least one gene (wA), whose mRNA does not occur in spores but rather accumulates in the sporogenous phialide cells, was activated by wetA, suggesting that wetA may have a regulatory function in these cells as well as in spores. We propose that wetA is responsible for activating a set of genes whose products make up the final two conidial wall layers or direct their assembly and through this activity is responsible for acquisition of spore dormancy.

A CONVENIENT METHOD OF OBTAINING ASCOSPORES FROM BAKERS' YEAST

1949 ◽  
Vol 27c (4) ◽  
pp. 179-189 ◽  
Author(s):  
A. M. Adams
Keyword(s):  
Convenient Method ◽  
Sodium Acetate ◽  
Solid Medium ◽  
Genetic Research ◽  
Yeast Cells ◽  
Sporulation Medium ◽  
Direct Transfer ◽  
Yeast Cultures ◽  
High Yields ◽  
Solid Nutrient Medium

The superiority of methods involving the use of sporulation media containing acetate, first introduced by Stantial and Elder, over several commonly employed methods is established. A new method for obtaining ascospores from bakers' yeast cultures is recommended involving the direct transfer of vegetative cells from a solid nutrient medium to a solid medium containing acetate. High yields of ascospores are consistently produced after seven days' incubation. This method should lend itself particularly to use in the preparation of ascospores for instructional work, and for genetic research in yeast, and may also find application in yeast taxonomy. The technique recommended is as follows: vegetative yeast cells are multiplied on tomato juice agar or on dextrose nutrient agar, and are then transferred to a solid sporulation medium containing 0.04% dextrose, 0.14% anhydrous sodium acetate, and 2% agar.

scholarly journals Structural Changes in Lettuce Seed During Germination at High Temperature Altered by Genotype, Seed Maturation Temperature, and Seed Priming

2008 ◽  
Vol 133 (2) ◽  
pp. 300-311 ◽  
Author(s):  
Yu Sung ◽  
Daniel J. Cantliffe ◽  
Russell T. Nagata ◽  
Warley M. Nascimento
Keyword(s):  
Cell Wall ◽  
High Temperature ◽  
Structural Changes ◽  
Anatomical Study ◽  
Seed Priming ◽  
Seed Maturation ◽  
Mechanical Resistance ◽  
Lettuce Seed ◽  
Endosperm Cell ◽  
Dark Green

To investigate thermotolerance in seeds of lettuce (Lactuca sativa L.), primed, nonprimed, or seeds matured at 20/10 and 30/20 °C (day/night on a 12-h photoperiod) were imbibed at 36 °C for various periods and then dissected. Structural changes in seed coverings in front of the radicle tip were observed during germination at high temperature. Thermotolerant genotypes, ‘Everglades’ and PI 251245, were compared with a thermosensitive cultivar, ‘Dark Green Boston’. In all seeds that germinated, regardless of seed maturation temperature or priming, a crack appeared on one side of the cap tissue (constriction of the endosperm membrane near the basal end of the seed) at the micropylar region and the endosperm separated from the integument in front of the radicle tip. Additional changes took place during imbibition in these seeds; the protein bodies in the vacuoles enlarged and gradually depleted, large empty vacuoles formed, the cytoplasm condensed, the endosperm shrank, the endosperm cell wall dissolved and ruptured, and then the radicle elongated toward this ruptured area. The findings suggested that the endosperm layer presented mechanical resistance to germination in seeds that could not germinate at 36 °C. Weakening of this layer was a prerequisite to radicle protrusion at high temperature. Seeds of ‘Dark Green Boston’, ‘Everglades’, and PI 251245 matured at 30/20 °C had greater thermotolerance than those matured at 20/10 °C. Results of the anatomical study indicated that the endosperm cell walls in front of the radicle of seeds matured at 30/20 °C were more readily disrupted and ruptured during imbibition than seeds matured at 20/10 °C, suggesting a reason why these seeds could germinate quickly at supraoptimal temperatures. Similar endosperm structural alterations also were observed in primed seeds. Priming led to rapid and uniform germination, circumventing the inhibitory effects of high temperatures. From anatomical studies conducted to identify and characterize thermotolerance in lettuce seed germination, we observed that genotype, seed maturation temperature, or seed priming had the ability to reduce physical resistance of the endosperm by weakening the cell wall and by depleting stored reserves leading to cell collapse.

scholarly journals Physiological function of Flo11p domains and the particular role of amyloid core sequences of this adhesin in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Clara Bouyx ◽  
Marion Schiavone ◽  
Marie-Ange Teste ◽  
Etienne Dague ◽  
Nathalie Sieczkowski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Amyloid Β ◽  
Surface Hydrophobicity ◽  
Yeast Cells ◽  
Invasive Growth ◽  
Specific Domain ◽  
A Genome ◽  
A Cell ◽  
Cellular Aggregates

Flocculins are a family of glycosylated proteins that provide yeast cells with several properties such as biofilm formation, flocculation, invasive growth or formation of velum. These proteins are similarly organised with a N-terminal (adhesion) domain, a stalk-like central B-domain with several repeats and a C-terminal sequence carrying a cell wall anchor site. They also contain amyloid β-aggregation-prone sequences whose functional role is still unclear. In this work, we show that Flo11p differs from other flocculins by the presence of unique amyloid-forming sequences, whose the number is critical in the formation of adhesion nanodomains under a physical shear force. Using a genome editing approach to identify the function of domains in Flo11p phenotypes, we show that the formation of cellular aggregates whose density increases with the number of amyloid sequences cannot be attributed to a specific domain of Flo11p. The same is true for plastic adhesion and surface hydrophobicity the intensity of which depends mainly on the abundance of Flo11p on the cell surface. In contrast, the N and C domains of Flo11p are essential for invasive growth in agar, whereas a reduction in the number of repeats of the B domain weakens this phenotype. However, expression of FLO11 alone is not sufficient to trigger this invasion phenotype. Finally, we show that this flocculin contributes to the integrity of the cell wall.

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