scholarly journals Influence of dinitroorthocresol (DNOC) on physiology and morphology of soil fungi. III. The effect of various concentrations of DNOC on spore germination activity and morphology of germ tubes

2014 ◽  
Vol 20 (1) ◽  
pp. 45-61 ◽  
Author(s):  
Teresa Korniłłowicz

In the present paper low concentrations (l -10 mcg/ml) of DNOC, in general, were not found to restrain germination of fungal spores. High concentrations (25-200 mcg/ml) were sporostatic and sporocidal Disturbances of fungal spore germination in the presence of DNOC were often accompanied by morphological changes of spores and germ tubes, <i>Mucor mucedo</i> under the influence of DNOC developed budding cels besides hyphae.

2016 ◽  
Vol 8 (5) ◽  
pp. 603-615 ◽  
Author(s):  
Layla J. Barkal ◽  
Naomi M. Walsh ◽  
Michael R. Botts ◽  
David J. Beebe ◽  
Christina M. Hull

Germination of a population of pathogenic fungal spores into yeast can be tracked, quantified, and parsed using a microfluidic assay.


2019 ◽  
Vol 68 (8) ◽  
pp. 718-730 ◽  
Author(s):  
Barzah Muazzam ◽  
Kashif Munawar ◽  
Imtiaz Ahmad Khan ◽  
Sarwat Jahan ◽  
Mazhar Iqbal ◽  
...  

Abstract Fish and other aquatic biota are hampered by mixtures of pesticides which pollute natural water through agricultural runoff and other sources. Toxicity of combined exposures of endosulfan and imidacloprid on zebrafish in terms of oxidative stress and deoxyribonucleic acid (DNA) damage in liver and histological alterations in gills and muscles was investigated. Zebrafish were exposed to three different sub-lethal concentrations of endosulfan and imidacloprid along with control selected for each treatment for 21 days: control treatment (CT), treatment 1 (T1), treatment 2 (T2) and treatment 3 (T3). T1, T2 and T3 groups were exposed to 0.1, 0.5 and 1 μg/L of endosulfan, respectively, while imidacloprid concentration was maintained at 1 ppm in all three treatments. Oxidative stress was evaluated by measuring levels of catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). Comet assay was applied to measure degree of DNA damage. Dose- and time-dependent decrease in SOD and CAT activity was observed after 21 days of exposure while low concentrations of pesticides induced SOD and CAT activities after early exposure to reduce the oxidative stress. MDA content was found to be increased in T3 having high concentrations of pesticides. Substantial increase in DNA damage was noticed after 21 days' exposure to pesticides. Significant morphological changes were observed in gills relative to muscles.


2020 ◽  
Vol 3 (3) ◽  
pp. 030-042
Author(s):  
Essien Benjamin Christopher

Fungal spores and hyphal fragments have been associated with out-door allergens and constitute human, animal and plant pathogens with long history of epidemiology. Airborne fungal spores of Akoko environment during the months of October 2016 to September 2017 were trapped and analyzed palynologicaly to determine the genera with allergic and pathogenic implications. Very high concentrations of these aerospora were documented. Out of 35 fungal spore type identified, the most commonly documented genera were species of Nigrospora, Endophragmiella, Ustilago, Botryodiplodia, Curvularia, Pithomyces, Corynespora and Venturia among others. The availability of these airborne fungal spore types is not only a reflection of their degree of abundance in the atmosphere, but an indication of the availability of host plants and other spore sources in the region. Statistical analysis shows that there was significant difference in the mean monthly fungal spore recorded. Multiple comparisons (using DMRT) showed that the mean fungal spores recorded in the month of October was significantly different (P<0.05) from that recorded in the month of July but not significantly different from those recorded for other months. Seasonal variation showed that the highest mean monthly fungal spore abundance were more from June - July and October - December due to higher sporulation activities by the fungi. This study would provide relevant information that could be useful in monitoring the frequency and intensity of fungal allergies and other pathogenic disease conditions of plants, animals and humans in the study environment and proffer adequate measures for safety health and environment.


2019 ◽  
Vol 63 (12) ◽  
Author(s):  
Sébastien C. Ortiz ◽  
Mingwei Huang ◽  
Christina M. Hull

ABSTRACT Spores are required for long-term survival of many organisms, including most fungi. For the majority of fatal human fungal pathogens, spore germination is the key process required to initiate vegetative growth and ultimately cause disease. Because germination is required for pathogenesis, the process could hold fungus-specific targets for new antifungal drug development. Compounds that inhibit germination could be developed into high-efficacy, low-toxicity drugs for use in the prevention and/or treatment of fungal spore-mediated diseases. To identify drugs with the ability to inhibit pathogenic fungal spore germination, we developed a novel luciferase-based germination assay, using spores of the meningitis-causing yeast Cryptococcus. We screened the L1300 Selleck Library of U.S Food and Drug Administration-approved drugs and identified 27 that inhibit germination. Of these, 22 inhibited both germination and yeast growth, and 21 have not been previously indicated for use in the treatment of fungal diseases. We quantitated the inhibition phenotypes of 10 specific germination/growth inhibitors in detail and tested one drug, the antiparasitic compound pentamidine, in our mouse intranasal model of cryptococcal infection. We discovered that pentamidine was effective at reducing lung fungal burdens when used in either prophylaxis (before infection) or treatment (after establishing an infection). Due to its efficacy in vivo and low intranasal toxicity, pentamidine is a lead candidate for repurposing for broader use as an antigerminant to prevent spore-mediated disease in immunocompromised patients. Not only does pentamidine provide an opportunity for prophylaxis against fungal spores, but it also provides proof of concept for targeting pathogenic spore germination for antifungal drug development.


Weed Science ◽  
1968 ◽  
Vol 16 (1) ◽  
pp. 55-57 ◽  
Author(s):  
C. D. Kesner ◽  
S. K. Ries

The growth of tomato (Lycopersicoti esculentum Mill., var. Heinz 1350) plants was enhanced by low concentrations of both N,N-dimethyl-2,2-diphenylacetamide (diphenamid) and the filtrate from two fungal species Trichoderma viride (Tode) Harz and Aspergillus candidus Link. High concentrations of the filtrate from these fungi inhibited the growth of tomatoes, but this was overcome by the addition of diphenamid. Diphenamid also increased the growth of these two fungi.


1970 ◽  
Vol 48 (12) ◽  
pp. 2109-2116 ◽  
Author(s):  
D. P. Webb ◽  
V. P. Agnihotri

The present data suggest that the pericarps of Acer saccharum contain a water-soluble fungal inhibitor that protects the fruit from fungal pathogens. Aqueous pericarp extracts effectively inhibited mycelial growth of several pathogenic soil fungi, particularly species of Pythium and Rhizoctonia. The extract also controlled damping-off of Pinus resinosa seedlings and inhibited microbial respiration in nursery soil. Even at relatively low concentrations (0.003% w/v), the extract lysed germ tubes and induced morphological abnormalities. Bioassays of chromatographically partitioned extracts indicated that four major compounds were present, one capable of markedly inhibiting germination of sporangia of Pythium irregulare. Two-dimensional paper chromatography of heat-treated extracts indicated that three additional spots were present. One spot showed characteristics of gallic acid; this suggests that the inhibitor is a gallotannin.


Author(s):  
A.J. Mia ◽  
L.X. Oakford ◽  
T. Yorio

The amphibian urinary bladder has been used as a ‘model’ system for studies of the mechanism of action of antidiuretic hormone (ADH) in stimulating transepithelial water flow. The increase in water permeability is accompanied by morphological changes that include the stimulation of apical microvilli, mobilization of microtubules and microfilaments and vesicular membrane fusion events . It has been shown that alterations in the cytosolic calcium concentrations can inhibit ADH transmembrane water flow and induce alterations in the epithelial cell cytomorphology, including the cytoskeletal system . Recently, the subapical granules of the granular cell in the amphibian urinary bladder have been shown to contain high concentrations of calcium, and it was suggested that these cytoplasmic constituents may act as calcium storage sites for intracellular calcium homeostasis. The present study utilizes the calcium antagonist, verapamil, to examine the effect of calcium deprivation on the cytomorphological features of epithelial cells from amphibian urinary bladder, with particular emphasis on subapical granule and microfilament distribution.


1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.


1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.


1970 ◽  
Vol 23 (03) ◽  
pp. 601-620 ◽  
Author(s):  
Th. B Tschopp

SummaryAggregation of cat platelets in the citrated plasma is examined by means of Born’s absorptiometer. A marked tendency of the platelets of this species to spontaneous aggregation necessitated first of all the development of an improved technique of blood collection.A hypothesis according to which 5-HT is released from the platelets, explains the absence of oscillations on the base line of the absorptiometer, the absence of platelet swelling, when ADP is added, and the effect of stirring on the aggregation curves in cat PRP. The average volume of cat platelets amounts to 10.46 μ3 when directly fixed in the blood, when fixed from PRP to 12.17 μ3, when fixed from stirred PRP to 13.51 μ3.In low concentrations (0.3-2 μM) ADP produce reversible aggregation; in narrowly restricted, individually dissimilar mean concentrations irreversible aggregation in two phases and in high concentrations, irreversible aggregation in one phase. Like ADP serotonin produces 2 phase irreversible aggregation in concentrations of 3-10 μM, but unlike ADP, the aggregation velocity decreases again with high 5-HT concentrations (>100 μM). Adrenaline does not produce aggregation and it is likely that adenosine and adenosine monophosphate inhibit the aggregation by serotonin but not by ADP. Species differences in the aggregation of human, rabbit and cat platelets are discussed.


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