From the editors — at the hyphal apex

Mycologist ◽  
2000 ◽  
Vol 14 (1) ◽  
pp. 44
Author(s):  
GH ◽  
RTM
Keyword(s):  
Hyphal Apex

Movement of nutrients in fungi. I. The Mycelium

1968 ◽  
Vol 16 (1) ◽  
pp. 71 ◽  
Author(s):  
LB Thrower ◽  
SL Thrower
Keyword(s):  
Nutrient Medium ◽  
Natural Habitat ◽  
Taxonomic Position ◽  
Deficient Medium ◽  
The Difference ◽  
Hyphal Apex

Thirty-one species of fungi (representing 13 orders) were examined for their ability to grow from a nutrient medium onto a non-nutrient medium; 17 were capable of colonizing the deficient medium, 10 were not, and 4 were indeterminate. The ability to grow onto deficient medium appeared to be related to the natural habitat of the fungus rather than to taxonomic position. Experiments with isotopically labelled nutrients showed that both colonizing fungi and non-colonizing fungi were capable of some transport of nutrients, the difference between the two groups being one of degree. In transporting fungi, labelled nutrients were moved more rapidly when the fungus colonized a deficient medium than when it colonized a nutrient medium; this suggested that movement of nutrients is adaptive to some extent. The importance of the growing hyphal apex as a sink for nutrients was demonstrated.

The role of the cytoskeleton in the movement and positioning of nuclei in Coprinus cinereus

1995 ◽  
Vol 73 (S1) ◽  
pp. 364-368 ◽  
Author(s):  
Takashi Kamada ◽  
Shigeru Tanabe
Keyword(s):  
Life Cycle ◽  
Immunofluorescence Microscopy ◽  
Coprinus Cinereus ◽  
Nuclear Movement ◽  
Nuclear Positioning ◽  
Mitotic Apparatus ◽  
Tubulin Mutations ◽  
Early Phases ◽  
Hyphal Apex

Coprinus cinereus exhibits conspicuous nuclear movement and precise nuclear positioning during its life cycle. Examples include transhyphal migration of nuclei in compatible mating giving rise to a dikaryon, nuclear positioning relative to the hyphal apex in the dikaryon, the close spacing in interphase and conjugate division of the two nuclei in the dikaryon, and the migration of nuclei from the basidium into developing spores. We have investigated the roles of the cytoskeleton in these processes using cytoskeleton mutants as well as fluorescence microscopy. Some of the α1- and β1-tubulin mutations examined blocked nuclear migration in dikaryosis and disturbed nuclear pairing in the dikaryon, demonstrating that microtubules are involved in these processes. The same mutations, however, did not affect the positioning of nuclei in interphase nor in conjugate division in the dikaryon, nor the migration of nuclei into the developing spores. Immunofluorescence microscopy revealed that these mutations inhibit the formation of asters of the mitotic apparatus in conjugate division, providing evidence against direct involvement of astral microtubules in nuclear movement during conjugate division. Actin was concentrated in hyphal regions where the nuclei sit in early phases of conjugate division, suggesting the involvement of actin in conjugate division. Key words: Coprinus cinereus, dikaryon, nuclear movement, microtubules, aster, actin.

Polarity of vesicle distribution in oomycete zoospores: development of polarity and importance for infection

1995 ◽  
Vol 73 (S1) ◽  
pp. 400-407 ◽  
Author(s):  
A. R. Hardham
Keyword(s):  
Adhesive Material ◽  
The Third ◽  
Polarized Secretion ◽  
Microtubular Cytoskeleton ◽  
Cell Components ◽  
Host Infection ◽  
Hyphal Apex ◽  
Peripheral Cytoplasm ◽  
Infective Agent

Biflagellate zoospores are the major infective agent for many pathogenic species of Oomycetes. Over the last 10 years, the use of a range of immunological techniques has greatly expanded our understanding of the ultrastructure of these cells and of the role a number of cell components play in the infection of a host. Three types of vesicles that occur in the peripheral cytoplasm of the zoospores have been well characterized. These vesicles show distinct polarities in their distribution within the zoospore cortex. Two are secretory and are thought to be responsible for the formation of the cyst coat and the deposition of adhesive material during encystment and host infection. The third vesicle type is not secreted and appears to serve as a store of proteins used to support early germling growth. All three vesicles are formed by the Golgi apparatus in hyphae following the induction of sporulation. They move into sporangia developing at the hyphal apex and are randomly distributed in the forming and mature sporangia. After the induction of sporangial cleavage, the vesicles are sorted into domains adjacent to the newly formed zoospore plasma membrane. This final sorting is dependent in some way on an intact microtubular cytoskeleton. Vesicle targeting and sorting is thus temporally and spatially removed from vesicle synthesis. Features of the oomycete zoospore system promise to make it a valuable one in which to conduct further studies of vesicle targeting, polarized secretion, and the role of the cytoskeleton in these processes. Key words: cytoskeleton, immunocytochemistry, Phytophthora, regulated secretion, sporulation.

Cell wall growth and protein secretion in fungi

1995 ◽  
Vol 73 (S1) ◽  
pp. 388-395 ◽  
Author(s):  
J. H. Sietsma ◽  
H. A. B. Wösten ◽  
J. G. H. Wessels
Keyword(s):  
Schizophyllum Commune ◽  
Outer Wall ◽  
Rigid Wall ◽  
Wall Material ◽  
Aerial Hyphae ◽  
Noncovalent Bonds ◽  
Wall Growth ◽  
Hyphal Wall ◽  
Wall Components ◽  
Hyphal Apex

Secretion of proteins is a vital process in fungi. Because hyphal walls form a diffusion barrier for proteins, a mechanism different from diffusion probably exist to transport proteins across the wall. In Schizophyllum commune, evidence has been obtained for synthesis at the hyphal apex of wall components, 1,3-β-glucan and chitin, as separate components. These become subapically cross-linked by formation of covalent and noncovalent bonds, producing a rigid wall (steady-state wall growth). Because the wall at the apex apparently grows by apposition of plastic wall material, proteins excreted at the apex may pass the wall by being carried with the flow of wall material (bulk flow), making pores in the wall less important than previously thought. A large portion of excreted proteins leaves hyphae at the growing apices, another portion is retained by the wall and slowly released from the mature wall into the environment. Among proteins that can be permanently retained by the wall are the hydrophobins that self-assemble at the outer wall surface when confronted with a hydrophilic–hydrophobic interface. They were shown to mediate both the emergence of aerial hyphae and the attachment of hyphae to hydrophobic substrates. Key words: hyphal wall, secretion of proteins, hydrophobins, aerial hyphae, apical growth, hyphal adhesion, wall growth.

Isolation and regeneration of protoplasts fromPenicillium digitatum

2004 ◽  
Vol 1 (3) ◽  
pp. 197-202 ◽  
Author(s):  
Song Ai-Huan ◽  
Li Hong-Ye ◽  
Liu Xiao-Hong
Keyword(s):  
Reaction Time ◽  
Osmotic Pressure ◽  
Double Layer ◽  
Material Resource ◽  
Regeneration Rate ◽  
Yield And Quality ◽  
Czapek Medium ◽  
Hyphal Apex ◽  
Pressure Stabilizer

AbstractThe effects of some factors on the isolation of protoplasts fromPenicillium digitatumwere studied, including the appropriate material (young mycelia and generating spores), the concentrations of enzyme and osmotic pressure stabilizers, reaction time and reaction temperature. Results demonstrated that germinating spores were an ideal material resource for the isolation ofP. digitatumprotoplasts. Highest yield and quality ofP. digitatumprotoplasts were obtained by shaking germinating spores suspended in a solution of 10 mg/ml Lywallzyme™ dissolved in 0.7 M NaCl as osmotic pressure stabilizer at 80 rev/min and 30°C for 3.0–3.5 h. The regeneration rate of the isolated protoplasts was as high as 24.9% on double-layer Czapek medium containing 0.7 M NaCl. Additionally, observation of the protoplast release pattern showed that the protoplasts ofP. digitatumwere released primarily from the hyphal apex and occasionally from the subapical or original sites of germinating tubes. The protoplasts ofP. digitatumwere regenerated in a direct manner of either yeast-like cell development or mycelium formation.

scholarly journals Basic-Zipper-Type Transcription Factor FlbB Controls Asexual Development in Aspergillus nidulans

2007 ◽  
Vol 7 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Oier Etxebeste ◽  
Min Ni ◽  
Aitor Garzia ◽  
Nak-Jung Kwon ◽  
Reinhard Fischer ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nuclear Import ◽  
Cell Types ◽  
Regulatory Elements ◽  
Asexual Development ◽  
Quantitative Expression ◽  
Functional Relations ◽  
Asexual Spore ◽  
Hyphal Apex ◽  
Fungal Colony

ABSTRACT The fungal colony is a complex multicellular unit consisting of various cell types and functions. Asexual spore formation (conidiation) is integrated through sensory and regulatory elements into the general morphogenetic plan, in which the activation of the transcription factor BrlA is the first determining step. A number of early regulatory elements acting upstream of BrlA (fluG and flbA-E) have been identified, but their functional relations remain to be further investigated. In this report we describe FlbB as a putative basic-zipper-type transcription factor restricted to filamentous fungi. FlbB accumulates at the hyphal apex during early vegetative growth but is later found in apical nuclei, suggesting that an activating modification triggers nuclear import. Moreover, proper temporal and quantitative expression of FlbB is a prerequisite for brlA transcription, and misscheduled overexpression inhibits conidiation. We also present evidence that FlbB activation results in the production of a second diffusible signal, acting downstream from the FluG factor, to induce conidiation.

scholarly journals Two Distinct Distributions of F-actin are Present in the Hyphal Apex of the Oomycete Achlya bisexualis

2004 ◽  
Vol 45 (3) ◽  
pp. 275-280 ◽  
Author(s):  
Yu Ping Yu ◽  
Sandra L. Jackson ◽  
Ashley Garrill
Keyword(s):  
Achlya Bisexualis ◽  
Hyphal Apex
Sign in / Sign up

Export Citation Format

Share Document