scholarly journals Growth inhibition of a phytopathogenic fungus, Colletotrichum species by acetic acid

2003 ◽  
Vol 158 (4) ◽  
pp. 321-326 ◽  
Author(s):  
Han-Chul Kang ◽  
Yong-Hwan Park ◽  
Seung-Joo Go
Keyword(s):  
Acetic Acid ◽  
Growth Inhibition ◽  
Phytopathogenic Fungus ◽  
Colletotrichum Species

scholarly journals Acetate-Mediated Growth Inhibition in Sterol 14α-Demethylation-Deficient Cells of Candida albicans

1999 ◽  
Vol 43 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Osamu Shimokawa ◽  
Hiroaki Nakayama
Keyword(s):  
Acetic Acid ◽  
Candida Albicans ◽  
Growth Inhibition ◽  
Sodium Acetate ◽  
Culture Medium ◽  
Susceptibility Testing ◽  
Agar Medium ◽  
Acetate Concentration ◽  
The Media ◽  
Layer Chromatography

ABSTRACT Candida albicans is a fungus thought to be viable in the presence of a deficiency in sterol 14α-demethylation. We showed in a strain of this species that the deficiency, caused either by a mutation or by an azole antifungal agent, made the cells susceptible to growth inhibition by acetate included in the culture medium. Studies with a mutant demonstrated that the inhibition was complete at a sodium acetate concentration of 0.24 M (20 g/liter) and was evident even at a pH of 8, the latter result indicating the involvement of acetate ions rather than the undissociated form of acetic acid. In fluconazole-treated cells, sterol profiles determined by thin-layer chromatography revealed that the minimum sterol 14α-demethylation-inhibitory concentrations (MDICs) of the drug, thought to be the most important parameter for clinical purposes, were practically identical in the media with and without 0.24 M acetate and were equivalent to the MIC in the acetate-supplemented medium. The acetate-mediated growth inhibition of azole-treated cells was confirmed with two additional strains of C. albicans and four different agents, suggesting the possibility of generalization. From these results, it was surmised that the acetate-containing medium may find use in azole susceptibility testing, for which there is currently no method capable of measuring MDICs directly for those fungi whose viability is not lost as a result of sterol 14α-demethylation deficiency. Additionally, the acetate-supplemented agar medium was found to be useful in detecting reversions from sterol 14α-demethylation deficiency to proficiency.

scholarly journals Herbicidal Activity of Curvulinic Acid Isolated from Nimbya alternantherae

2012 ◽  
Vol 7 (1) ◽  
pp. 1934578X1200700
Author(s):  
Jun Li ◽  
Yonghao Ye ◽  
Xiaoyang Wang ◽  
Liyao Dong
Keyword(s):  
Acetic Acid ◽  
Seed Germination ◽  
Root Length ◽  
Shoot Length ◽  
Herbicidal Activity ◽  
Phytopathogenic Fungus ◽  
Inhibitory Effects ◽  
Liquid Cultures ◽  
First Time ◽  
Phytotoxic Compound

A phytotoxic compound, identified as 2-(2-acetyl-3,5-dihydroxyphenyl) acetic acid (curvulinic acid), was isolated from liquid cultures of the phytopathogenic fungus Nimbya alternantherae. The activity of curvulinic acid on seed germination and seedling growth of Capsella bursa-pastoris was evaluated. Percentage seed germination of C. bursa-pastoris was decreased with increasing concentrations of curvulinic acid. The compound had stronger inhibitory effects on root length than shoot length. At a concentration of 600 μg·mL−1, curvulinic acid caused 73.5% and 66.7% growth inhibition on roots and shoots with IC50 values of 204.7 and 281.1 μg·mL−1, respectively. The finding of curvulinic acid in N. alternantherae and its herbicidal activity are reported here for the first time.

Response of Soil Algae to Picloram-2,4-D Mixtures

Weed Science ◽  
1971 ◽  
Vol 19 (3) ◽  
pp. 276-278 ◽  
Author(s):  
J. H. Arvik ◽  
D. L. Willson ◽  
L. C. Darlington
Keyword(s):  
Acetic Acid ◽  
Growth Inhibition ◽  
Natural Population ◽  
Chlorella Vulgaris ◽  
Algal Flora ◽  
Soil Algae ◽  
Inhibitory Effects ◽  
Commercial Mixture ◽  
Dichlorophenoxy Acetic Acid

The effects of an approximate 1:4 commercial mixture of 4-amino-3,5,6-trichloropicolinic acid (picloram) and (2,4-dichlorophenoxy)acetic acid (2,4-D) on a natural population of soil algae were studied at dosages of 0.28, 0.56, and 1.12 kg/ha of picloram. No change in the composition of the algal flora was noted over an 18-month period, regardless of dosage.In vitrostudies indicated that mixtures of picloram and 2,4-D inhibited growth ofChlorella vulgarisBeyer. at concentrations above 100 ppm, but concentrations above 250 ppm were needed for growth inhibition ofCylindrospermum licheniforme(Bory) Kuetz. orChlorococcumsp. Picloram alone inhibited all three algae at 50 ppm, while 2,4-D produced no inhibitory effects at concentrations less than 400 ppm.

scholarly journals Local Modulation of Host pH by Colletotrichum Species as a Mechanism to Increase Virulence

2001 ◽  
Vol 14 (9) ◽  
pp. 1105-1113 ◽  
Author(s):  
Dov Prusky ◽  
James L. McEvoy ◽  
Britta Leverentz ◽  
William S. Conway
Keyword(s):  
Virulence Factor ◽  
Pectate Lyase ◽  
Colletotrichum Acutatum ◽  
Phytopathogenic Fungus ◽  
Ph Change ◽  
Colletotrichum Species ◽  
Ammonia Accumulation ◽  
Yeast Extract Medium ◽  
Initial Ph ◽  
Infected Area

The phytopathogenic fungus Colletotrichum gloeosporioides produces one pectate lyase (PL) that is a key virulence factor in disease development. During growth of C. gloeosporioides, Colletotrichum acutatum, and Colletotrichum coccodes in acidified yeast extract medium, the fungus secreted ammonia and increased the medium pH. Ammonia accumulation and the consequent pH change increased as a function of initial pH and buffer capacity of the medium. PL secretion by C. gloeosporioides correspondingly increased as the pH of the medium increased. The C. gloeosporioides pelB gene-disrupted mutant was able to increase ammonia accumulation and pH of the media similarly to the wild-type isolate. C. gloeosporioides in avocado, C. coccodes in tomato, and C. acutatum in apple showed ammonia accumulation in the infected area where pH increased to 7.5 to 8 and PL activity is optima. In nonhost interactions where C. gloeosporioides was inoculated in apples, the addition of ammonia-releasing compounds significantly enhanced pathogenicity to levels similar to those caused by the compatible C. acutatum-apple interaction. The results therefore suggest the importance of ammonia secretion as a virulence factor, enhancing environmental pH and pathogenicity of the Colletotrichum species.

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