Fungal fimbriae. I. Structure, origin, and synthesis

1975 ◽  
Vol 21 (4) ◽  
pp. 537-546 ◽  
Author(s):  
N. H. Poon ◽  
A. W. Day
Keyword(s):  
Cell Walls ◽  
High Speed ◽  
De Novo ◽  
Sucrose Solution ◽  
Gram Negative Bacteria ◽  
Fine Hair ◽  
Ustilago Violacea ◽  
Anther Smut ◽  
De Novo Protein Synthesis ◽  
Cytoplasmic Ribosomes

Fine hair-like appendages on the cell walls of the anther smut Ustilago violacea are described. These hairs are termed fimbriae because of their close similarity to the fimbriae (pili) found on certain Gram-negative bacteria. Cells of U. violacea may carry more than 200 fimbriae varying in length from about 0.5 μm to over 10 μm, and having a diameter of about 60–70 Å. Some fimbriae produce knobs similar to those found on bacterial sex fimbriae. Log-phase cells are the most densely fimbriated, while stationary phase cells are devoid of fimbriae. The cells can be de-fimbriated by sonication, high-speed agitation, or centrifugation through a 40% sucrose solution. The fimbriae can regenerate in these defimbriated cells in about 1 h. This regeneration is inhibited by both cycloheximide and rifampin, but not by chloramphenicol and therefore appears to depend on de novo protein synthesis on cytoplasmic ribosomes. Similar long fimbriae are found on U. maydis and Leucosporidium (Candida) scottii. Short fimbriae, about 0.5 μm long, were found on all the other species of yeast-like fungi examined (Rhodotorula, Saccharomyces, Schizosaccharomyces, Hansenula, Lipomyces, Nadsonia, and Torulopsis spp.).

Conjugation in Ustilago violacea. I. Morphology

1974 ◽  
Vol 20 (2) ◽  
pp. 187-191 ◽  
Author(s):  
N. H. Poon ◽  
J. Martin ◽  
A. W. Day
Keyword(s):  
Cell Cycle ◽  
Mating Type ◽  
Electron Micrographs ◽  
Cell Walls ◽  
Plasma Membranes ◽  
Smut Fungus ◽  
Type Ii ◽  
Opposite Mating Type ◽  
Ustilago Violacea ◽  
Anther Smut

Conjugation in the anther smut fungus, Ustilago violacea, is described and five stages are characterized viz. (i) intimate pairing of cells of opposite mating type; (ii) development of bumps from each cell at the point of pairing. The cell walls of opposing pegs are fused, but the plasma membranes are not yet affected; (iii) elongation of the bumps into pegs; (iv) dissolution of the walls and plasma membranes of opposing pegs at the point of contact, and the formation of a tube; (v) elongation of the tube to the mature mating configuration (about 5 μm). Electron micrographs and Nomarski interference contrast micrographs of this sequence are illustrated. The assembly of the conjugation tube begins as early as 1.5 h after the cells are mixed on mating medium and is completed in about 45 min. Even in asynchronous populations there is a burst of synchronous mating, followed by later asynchronous mating. Observations on the ability to mate of unbudded and budded cells support the evidence from cell cycle work that allele a1 mates only in the G1 phase (unbudded) while allele a2 is competent to mate during all phases.

scholarly journals Viral Gene Expression Patterns in Human Herpesvirus 6B-Infected T Cells

2002 ◽  
Vol 76 (15) ◽  
pp. 7578-7586 ◽  
Author(s):  
Bodil Øster ◽  
Per Höllsberg
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Protein Synthesis ◽  
De Novo ◽  
Expression Patterns ◽  
Human Herpesvirus ◽  
Viral Gene Expression ◽  
Polymerase Activity ◽  
Viral Gene ◽  
De Novo Protein Synthesis

ABSTRACT Herpesvirus gene expression is divided into immediate-early (IE) or α genes, early (E) or β genes, and late (L) or γ genes on the basis of temporal expression and dependency on other gene products. By using real-time PCR, we have investigated the expression of 35 human herpesvirus 6B (HHV-6B) genes in T cells infected by strain PL-1. Kinetic analysis and dependency on de novo protein synthesis and viral DNA polymerase activity suggest that the HHV-6B genes segregate into six separate kinetic groups. The genes expressed early (groups I and II) and late (groups V and VI) corresponded well with IE and L genes, whereas the intermediate groups III and IV contained E and L genes. Although HHV-6B has characteristics similar to those of other roseoloviruses in its overall gene regulation, we detected three B-variant-specific IE genes. Moreover, genes that were independent of de novo protein synthesis clustered in an area of the viral genome that has the lowest identity to the HHV-6A variant. The organization of IE genes in an area of the genome that differs from that of HHV-6A underscores the distinct differences between HHV-6B and HHV-6A and may provide a basis for further molecular and immunological analyses to elucidate their different biological behaviors.

De novo protein synthesis in relation to ammonia and proline accumulation in water stressed white clover

2004 ◽  
Vol 31 (8) ◽  
pp. 847 ◽  
Author(s):  
Tae-Hwan Kim ◽  
Bok-Rye Lee ◽  
Woo-Jin Jung ◽  
Kil-Yong Kim ◽  
Jean-Christophe Avice ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Water Deficit ◽  
White Clover ◽  
De Novo ◽  
Proline Accumulation ◽  
Leaf Water ◽  
Total N ◽  
Water Parameters ◽  
Leaves And Roots ◽  
De Novo Protein Synthesis

The kinetics of protein incorporation from newly-absorbed nitrogen (N, de novo protein synthesis) was estimated by 15N tracing in 18-week-old white clover plants (Trifolium repens L. cv. Regal) during 7 d of water-deficit treatment. The physiological relationship between kinetics and accumulation of proline and ammonia in response to the change in leaf-water parameters was also assessed. All leaf-water parameters measured decreased gradually under water deficit. Leaf and root dry mass was not significantly affected during the first 3 d when decreases in leaf-water parameters were substantial. However, metabolic parameters such as total N, proline and ammonia were significantly affected within 1 d of commencement of water-deficit treatment. Water-deficit treatment significantly increased the proline and NH3–NH4+ concentrations in both leaves and roots. There was a marked reduction in the amount of N incorporated into the protein fraction from the newly absorbed N (NANP) in water-deficit stressed plants, particularly in leaf tissue. This reduction in NANP was strongly associated with an increased concentration of NH3–NH4+ in roots (P≤0.05) and proline (P≤0.01) in leaves and roots. These results suggest that proline accumulation may be a sensitive biochemical indicator of plant water status and of the dynamics of de novo protein synthesis in response to stress severity.

Cell Walls Are Remodeled to Alleviate nY2O3 Cytotoxicity by Elaborate Regulation of de Novo Synthesis and Vesicular Transport

ACS Nano ◽  
2021 ◽  
Author(s):  
Feiran Chen ◽  
Chuanxi Wang ◽  
Le Yue ◽  
Liqi Zhu ◽  
Junfeng Tang ◽  
...  
Keyword(s):  
Cell Walls ◽  
De Novo ◽  
Vesicular Transport ◽  
De Novo Synthesis

Regulation of the transcript for a lysosomal protein: evidence for a gene program modified by platelet-derived growth factor

1985 ◽  
Vol 5 (10) ◽  
pp. 2582-2589
Author(s):  
K K Frick ◽  
P J Doherty ◽  
M M Gottesman ◽  
C D Scher
Keyword(s):  
Growth Factor ◽  
De Novo ◽  
Platelet Derived Growth Factor ◽  
Tumor Promoter ◽  
3T3 Cells ◽  
Somatomedin C ◽  
Epidermal Growth ◽  
Rna Accumulation ◽  
De Novo Protein Synthesis ◽  
Lysosomal Protein

Platelet-derived growth factor (PDGF) stimulates density-arrested BALB/c-3T3 cells to synthesize MEP, a lysosomal protein. This enhanced synthesis appears to be largely regulated by the PDGF-modulated accumulation of MEP mRNA, a 1.8-kilobase species. The increase in the MEP transcript, which is dependent on the PDGF concentration, begins 3 to 4 h after PDGF addition and is maximal at 12 h. The accumulation of the MEP transcript is growth-factor specific: PDGF and the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, an agent which acts like PDGF, induce MEP RNA accumulation, whereas epidermal growth factor, somatomedin C, insulin, and whole plasma do not. A spontaneously transformed BALB/c-3T3 cell line (ST2-3T3), which does not require PDGF for growth, optimally expresses MEP RNA in the absence of PDGF. The PDGF-modulated increase in MEP RNA is unlike PDGF-modulated c-myc and c-fos RNA accumulation because it is blocked by cycloheximide, suggesting a requirement for de novo protein synthesis. It appears that PDGF modulates a program of gene expression with the accumulation of some transcripts, typified by MEP, being dependent upon the translation of others.

Biological Seed Treatments

2021 ◽  
Author(s):  
Gary Harman
Keyword(s):  
Shelf Life ◽  
Environmental Sustainability ◽  
Cell Walls ◽  
Solid Matrix ◽  
Gram Negative Bacteria ◽  
Seed Treatments ◽  
Proper Formulation ◽  
Living Organisms ◽  
Bacteria And Fungi ◽  
Microbial Agents

Abstract Bacteria and fungi are both used in biological seed treatments. While all have potential uses, some organisms are more widely and successfully used than others. Shelf life is an important consideration. For this reason, organisms that lack cell walls are more difficult to use than ones with long-lasting spores. Bacillus and Trichoderma are both widely effective, have good shelf life, and are frequently used. However, Rhizobiacae lack cell walls, which is a limitation; they are widely used because their symbiosis with legumes facilitates nitrogen fixation which is an important factor that provides economic, agricultural and environmental sustainability. For all organisms, proper formulation is critical for success; this is especially true for Rhizobiacae and other gram-negative bacteria. There are several specialized processes to deliver microbial agents or to enhance their biological activity, such as solid matrix priming and hydroseeding. Biorational chemicals derived from microorganisms are also frequently used. Both living organisms and biorationals provide benefits to plant agriculture. They can control diseases and increase resistance to abiotic stresses such as drought, temperature, salt, and flooding. They also can enhance mineral nutrition and photosynthesis. For these applications, the most effective ones colonize roots internally and provide season-long benefits. These endophytes induce systemic changes in plants’ gene expression and encoding of proteins.

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