Growth and ultrastructural differentiation of sporangia in Phytophthora palmivora

1972 ◽  
Vol 18 (12) ◽  
pp. 1959-1964 ◽  
Author(s):  
Josef Christen ◽  
Hans R. Hohl
Keyword(s):  
Cell Expansion ◽  
Tip Growth ◽  
Phytophthora Palmivora ◽  
Wall Thickening ◽  
Complete Occlusion ◽  
Papilla Formation ◽  
Apical Papilla ◽  
Plug Formation ◽  
Sporangial Wall ◽  
Hyphal Tip

Development of sporangia in Phytophthora palmivora Butler consists of two main stages. The first involves expansion of the sporangial initial to about the size of the mature sporangium, whereas the second is characterized by the differentiation of the expanded vesicle to the mature sporangium. Differentiation includes basal plug formation, secondary sporangial wall thickening, and apical papilla formation.Expansion of the sporangial initial appears to be mainly the result of cytoplasmic inflow from the mycelial mat coupled with surface growth of the vesicle wall. Basal plug formation terminates the phase of expansion. The process of plug formation involves deposition of wall-like material at the base of the expanded vesicle. The depositions, which grow from the periphery towards the center of the sporangiophore, are at first rather irregular in shape but eventually lead to complete occlusion, thus separating the immature sporangium from the sporangiophore. Sporangial wall thickening starts at the basal plug and progresses towards the developing apical papilla. Papilla formation is initiated by an apical bulge of the immature sporangium. The cytoplasm within the bulge is specialized and characterized mainly by populations of small (50–100 nm) and large (about 250 nm) vesicles, which appear to be involved in papilla formation. Papilla deposition resembles hyphal tip growth in the absence of cell expansion.

Potent Chitin Synthase Inhibitors from Plants

2020 ◽  
Vol 16 (1) ◽  
pp. 58-63
Author(s):  
Amrutha Vijayakumar ◽  
Ajith Madhavan ◽  
Chinchu Bose ◽  
Pandurangan Nanjan ◽  
Sindhu S. Kokkal ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Caenorhabditis Elegans ◽  
Aspergillus Niger ◽  
Small Molecules ◽  
Tip Growth ◽  
Chitin Synthase ◽  
Chitin Synthesis ◽  
Hyphal Tip Growth ◽  
Hyphal Tip

Background: Chitin is the main component of fungal, protozoan and helminth cell wall. They help to maintain the structural and functional characteristics of these organisms. The chitin wall is dynamic and is repaired, rearranged and synthesized as the cells develop. Active synthesis can be noticed during cytokinesis, laying of primary septum, maintenance of lateral cell wall integrity and hyphal tip growth. Chitin synthesis involves coordinated action of two enzymes namely, chitin synthase (that lays new cell wall) and chitinase (that removes the older ones). Since chitin synthase is conserved in different eukaryotic microorganisms that can be a ‘soft target’ for inhibition with small molecules. When chitin synthase is inhibited, it leads to the loss of viability of cells owing to the self- disruption of the cell wall by existing chitinase. Methods: In the described study, small molecules from plant sources were screened for their ability to interfere with hyphal tip growth, by employing Hyphal Tip Burst assay (HTB). Aspergillus niger was used as the model organism. The specific role of these small molecules in interfering with chitin synthesis was established with an in-vitro method. The enzyme required was isolated from Aspergillus niger and its activity was deduced through a novel method involving non-radioactively labelled substrate. The activity of the potential lead molecules were also checked against Candida albicans and Caenorhabditis elegans. The latter was adopted as a surrogate for the pathogenic helminths as it shares similarity with regard to cell wall structure and biochemistry. Moreover, it is widely studied and the methodologies are well established. Results: Out of the 11 compounds and extracts screened, 8 were found to be prospective. They were also found to be effective against Candida albicans and Caenorhabditis elegans. Conclusion: Purified Methyl Ethyl Ketone (MEK) Fraction1 (F1) of Coconut (Cocos nucifera) Shell Extract (COSE) was found to be more effective against Candida albicans with an IC50 value of 3.04 μg/mL and on L4 stage of Caenorhabditis elegans with an IC50 of 77.8 μg/mL.

scholarly journals Model of hyphal tip growth involving microtubule-based transport

2007 ◽  
Vol 75 (3) ◽  
Author(s):  
K. E. P. Sugden ◽  
M. R. Evans ◽  
W. C. K. Poon ◽  
N. D. Read
Keyword(s):  
Tip Growth ◽  
Hyphal Tip Growth ◽  
Hyphal Tip

Mechanisms of Hyphal Tip Growth and Morphogenesis in the Filamentous Fungus Neurospora crassa

2004 ◽  
Vol 10 (S02) ◽  
pp. 1554-1555
Author(s):  
Maho Uchida ◽  
Solomon Bartnicki-García ◽  
Robert W. Roberson
Keyword(s):  
Neurospora Crassa ◽  
Filamentous Fungus ◽  
Tip Growth ◽  
Hyphal Tip Growth ◽  
Hyphal Tip

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

Computer modelling of hyphal tip growth in fungi

1972 ◽  
Vol 50 (12) ◽  
pp. 2455-2462 ◽  
Author(s):  
Daniela da Riva Ricci ◽  
Bryce Kendrick
Keyword(s):  
Mathematical Model ◽  
Tip Growth ◽  
Computer Modelling ◽  
Hyphal Tip Growth ◽  
Hyphal Tip

Starting from simple morphological considerations and a hypothesis involving 'unset' and 'set' wall, a mathematical model simulating the growth of the hyphal tip is derived, and the results displayed by plotter.

scholarly journals Electrical Phenotypes of Calcium Transport Mutant Strains of a Filamentous Fungus, Neurospora crassa

2012 ◽  
Vol 11 (5) ◽  
pp. 694-702 ◽  
Author(s):  
Ahmed Hamam ◽  
Roger R. Lew
Keyword(s):  
Atpase Activity ◽  
Calcium Transport ◽  
Tip Growth ◽  
Electrical Characterization ◽  
Mechanosensitive Channel ◽  
Wild Type ◽  
Current Voltage ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Hyphal Tip

ABSTRACT We characterized the electrical phenotypes of mutants with mutations in genes encoding calcium transporters—a mechanosensitive channel homolog ( MscS ), a Ca 2+ /H + exchange protein ( cax ), and Ca 2+ -ATPases ( nca-1 , nca-2 , nca-3 )—as well as those of double mutants (the nca-2 cax , nca-2 nca-3 , and nca-3 cax mutants). The electrical characterization used dual impalements to obtain cable-corrected current-voltage measurements. Only two types of mutants (the MscS mutant; the nca-2 mutant and nca-2 -containing double mutants) exhibited lower resting potentials. For the nca-2 mutant, on the basis of unchanged conductance and cyanide-induced depolarization of the potential, the cause is attenuated H + -ATPase activity. The growth of the nca-2 mutant-containing strains was inhibited by elevated extracellular Ca 2+ levels, indicative of lesions in Ca 2+ homeostasis. However, the net Ca 2+ effluxes of the nca-2 mutant, measured noninvasively with a self-referencing Ca 2+ -selective microelectrode, were similar to those of the wild type. All of the mutants exhibited osmosensitivity similar to that of the wild type (the turgor of the nca-2 mutant was also similar to that of the wild type), suggesting that Ca 2+ signaling does not play a role in osmoregulation. The hyphal tip morphology and tip-localized mitochondria of the nca-2 mutant were similar to those of the wild type, even when the external [Ca 2+ ] was elevated. Thus, although Ca 2+ homeostasis is perturbed in the nca-2 mutant (B. J. Bowman et al., Eukaryot. Cell 10:654–661, 2011), the phenotype does not extend to tip growth or to osmoregulation but is revealed by lower H + -ATPase activity.

scholarly journals The Ashbya gossypii fimbrin SAC6 is required for fast polarized hyphal tip growth and endocytosis

2011 ◽  
Vol 166 (3) ◽  
pp. 137-145 ◽  
Author(s):  
Sigyn Jorde ◽  
Andrea Walther ◽  
Jürgen Wendland
Keyword(s):  
Tip Growth ◽  
Ashbya Gossypii ◽  
Hyphal Tip Growth ◽  
Hyphal Tip
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