scholarly journals In vivo observation of conidial germination at the oxic–anoxic interface and infection of submerged reed roots by Microdochium bolleyi

2003 ◽  
Vol 45 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Ulrike Damm ◽  
Andreas Brune ◽  
Kurt Mendgen
Keyword(s):  
Conidial Germination ◽  
Microdochium Bolleyi

scholarly journals Efficiency of a new Waitea circinata extract against rice pathogens

2021 ◽  
Vol 51 ◽  
Author(s):  
Jacqueline Campos Borba de Carvalho ◽  
Amanda Abdallah Chaibub ◽  
Kellen Cristhina Inácio Sousa ◽  
Denise Candini de Brito ◽  
Marta Cristina Corsi de Filippi ◽  
...  
Keyword(s):  
Rice Blast ◽  
Mycorrhizal Fungus ◽  
Conidial Germination ◽  
Appressorium Formation ◽  
Vitro Assay ◽  
Rice Pathogens ◽  
Waitea Circinata ◽  
Mycelial Mass

ABSTRACT Waitea circinata (Warcup & Talbot) is an orchid antagonist mycorrhizal fungus with biocontrol potential against rice pathogens. This study aimed to optimize the extraction method, obtain a new extract and evaluate its efficiency against rice pathogens in vitro and in vivo, as well as to compare it with other extraction methods and W. circinata. The extracts were obtained and screened for in vitro growth inhibition against the pathogens Cochliobolus miyabeanus, Monographella albescens and Sarocladium oryzae, using the following extracts: mycelial, crude, lyophilized and mycelial mass. An additional in vitro assay was performed with the principal rice pathogen (Magnaporthe oryzae), in order to evaluate the conidial germination and appressorium formation. Based on this evaluation, the lyophilized and mycelial mass extracts were tested in vivo against rice blast (M. oryzae) and compared to the W. circinata mycelial suspension, in different application forms (simultaneous and previous). The mycelial mass extract inhibited all the pathogens, and the crude and lyophilized extracts inhibited C. miyabeanus and M. albescens, respectively. The mycelial mass extract inhibited the M. oryzae conidial germination and appressorium formation by 80 %, and the simultaneous and previous applications suppressed the rice blast by 94 %. These results indicate that the new extract can be used to control rice pathogens.

scholarly journals Aktivitas Metabolit Sekunder Cendawan Endofit terhadap Colletotrichum acutatum pada Cabai Merah

2019 ◽  
Vol 15 (1) ◽  
pp. 36
Author(s):  
Nur Alfi Saryanah ◽  
Suryo Wiyono ◽  
Dadang Dadang
Keyword(s):  
Antifungal Activity ◽  
Ethyl Acetate Extract ◽  
Fungal Endophyte ◽  
In Vitro Assay ◽  
Conidial Germination ◽  
Colletotrichum Acutatum ◽  
Methanol Fraction ◽  
Vitro Assay

Activity of Fungal Endophyte Secondary Metabolites against Colletotrichum acutatum on Chili PepperColletotrichum acutatum is one of anthracnose causal agents on chili pepper that has been reported to be predominant species in a some regions of Java Island. Secondary metabolites of endophytic fungi have been reported to have a potency as antifungal agents against plant pathogen. However, its antifungal activity against C. acutatum has not been reported yet. This study was aimed to evaluate the antifungal activity of fungal endophyte secondary metabolite against C. acutatum at in vitro and in vivo assay. In vitro assay was conducted to evaluate antifungal activity of fungal endophyte CBR1D14 isolate culture filtrate (FCBR) and mycelia extract (MCBR) in inhibiting conidial germination of C. acutatum. The results of in vitro assay showed that ethyl acetate extract of FCBR (EA FCBR) had the highest activity in inhibiting C. acutatum conidial germination. Methanol fraction from the partition of EA FCBR (FM FCBR) and from the partition of MCBR ethyl acetate extract (FM MCBR) showed the ability in inhibiting C. acutatum conidial germination. In vivo assay to chili pepper fruit showed that the treatment of FM FCBR (IC95 609.9 µg mL-1) and FM MCBR (IC95 1178.27 µg mL-1) decreased anthracnose disease incidence and lesion diameter. The efficacy rate of FM FCBR and FM MCBR treatments against anthracnose was 36.72 and 48.68%, respectively. Bioautography test was done on silica gel thin layer chromatogram. Methanol fraction of FCBR and MCBR were separated into 3 bioautographic spots respectively (Rf 0.04, 0.07, 0.7 for FM FCBR and Rf 0.06, 0.52, 0.7 for FM MCBR).

scholarly journals Resistance to Pyraclostrobin and Boscalid in Populations of Botrytis cinerea from Stored Apples in Washington State

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 604-612 ◽  
Author(s):  
Y. K. Kim ◽  
C. L. Xiao
Keyword(s):  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Gray Mold ◽  
Apple Fruit ◽  
Conidial Germination ◽  
Postharvest Disease ◽  
Cross Resistance ◽  
Baseline Sensitivity

Gray mold caused by Botrytis cinerea is a major postharvest disease of apple. Pristine, a formulated mixture of pyraclostrobin and boscalid, was recently registered for use on apple. Pristine applied within 2 weeks before harvest is effective in controlling gray mold in stored apple fruit. To determine the baseline sensitivity of B. cinerea populations to these fungicides, 40 isolates from organic and 80 from conventional apple orchards where Pristine had not been used were tested for mycelial growth or conidial germination on fungicide-amended media. To monitor fungicide resistance, gray-mold-decayed apple fruit originating from orchards in which Pristine had been used were sampled from a fruit packinghouse. Isolates of B. cinerea recovered from the fruit were tested for resistance to the two fungicides. In the in vivo study in the orchards, Pristine was applied to fruit 1 day before harvest. Fruit were then harvested, wounded, and inoculated with isolates exhibiting different fungicide-resistance phenotypes. Fruit were stored at 0°C for 8 weeks for decay development. The effective concentration that inhibits mycelial growth by 50% relative to the control (EC50) values for sensitive isolates ranged from 0.008 to 0.132 μg/ml (mean = 0.043, n = 116) for pyraclostrobin and from 0.003 to 0.183 μg/ml (mean = 0.075, n = 117) for Pristine in a mycelial growth assay on potato dextrose agar. The EC50 values of boscalid for sensitive isolates ranged from 0.065 to 1.538 μg/ml (mean = 0.631, n = 29) in a conidial germination assay on water agar. Four isolates were resistant to pyraclostrobin, with resistance factors (RFs) ranging from 12 to 4,193. Of the four pyraclostrobin-resistant isolates, one also was resistant to boscalid (RF = 14) and Pristine (RF = 373), and two exhibited reduced sensitivity to Pristine (RF = 16 and 17). The minimum inhibitory concentration for conidial germination (for boscalid) or mycelial growth (for pyraclostrobin and Pristine) of sensitive isolates was 5 μg/ml, which is thus recommended as a discriminatory concentration for phenotyping isolates for resistance to these fungicides. Of the 56 isolates obtained from decayed apple fruit that had been exposed to Pristine, 11 (approximately 20%) were resistant to both pyraclostrobin and boscalid and 1 was resistant only to pyraclostrobin. Of the additional 43 isolates obtained from decayed apple fruit originating from an organic orchard, 3 were resistant only to pyraclostrobin, 2 were resistant only to boscalid, and 2 were resistant to both fungicides. It appeared that there was no cross resistance between pyraclostrobin and boscalid because of the existence of isolates resistant only to either pyraclostrobin or boscalid. Pristine applied at label rate in the orchard failed to control gray mold on apple fruit inoculated with the Pristine-resistant isolates. This is the first report of multiple resistance to pyraclostrobin, boscalid, and Pristine in field populations of B. cinerea. Our results suggest that the development of dual resistance to pyraclostrobin and boscalid in B. cinerea populations could result in the failure to control gray mold with Pristine.

scholarly journals Entomophthora muscae — moisture as a factor affecting its transmission and conidial germination

2014 ◽  
Vol 16 (1) ◽  
pp. 133-139 ◽  
Author(s):  
John P. Kramer
Keyword(s):  
Microscopical Study ◽  
Conidial Germination ◽  
Dominant Form ◽  
Entomophthora Muscae ◽  
House Flies ◽  
Resting Spores

The role played by moisture in the transmission of <i>Entomophthora muscae</i> and in the germination of its conidia was investigated. A majority of adult house flies exposed to conidial showers that fell upon surfaces covered with droplets of condensation acquired the parasite, while no flies exposed to conidial showers that fell upon dry surfaces did so. A microscopical study of conidial showers showed that germination was practically non-existent on dry surfaces while a vast majority of conidia that fell upon a droplet-covered surface germinated. A method for the <i>in vivo</i> culture of <i>E. muscae</i> was developpd and 11 serial passages of the fungus were achieved. Resting spores rather than conidia became the dominant form produced in the cadavers, and flies in a twelfth group remained unifected.

scholarly journals Reduced Sensitivity in Monilinia fructicola Field Isolates from South Carolina and Georgia to Respiration Inhibitor Fungicides

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 737-743 ◽  
Author(s):  
A. Amiri ◽  
P. M. Brannen ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Brown Rot ◽  
Conidial Germination ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Significant Difference

Quinone outside inhibitor (QoI) and succinate dehydrogenase inhibitor (SdhI) fungicides are respiration inhibitors (RIs) used for preharvest control of brown rot of stone fruit. Both chemical classes are site-specific and, thus, prone to resistance development. Between 2006 and 2008, 157 isolates of Monilinia fructicola collected from multiple peach and nectarine orchards with or without RI spray history in South Carolina and Georgia were characterized based upon conidial germination and mycelial growth inhibition for their sensitivity to QoI fungicides azoxystrobin and pyraclostrobin, SdhI fungicide boscalid, and a mixture of pyraclostrobin + boscalid. There was no significant difference (P = 0.05) between EC50 values for inhibition of conidial germination versus mycelial growth. The mean EC50 values based upon mycelial growth tests for 25 isolates from an orchard without RI-spray history were 0.15, 0.06, 2.23, and 0.09 μg/ml for azoxystrobin, pyraclostrobin, boscalid, and pyraclostrobin + boscalid, respectively. The respective mean EC50 values for 76 isolates from RI-sprayed orchards in South Carolina were 0.9, 0.1, 10.7, and 0.13 μg/ml and for 56 isolates from RI-sprayed orchards in Georgia were 1.2, 0.1, 8.91, and 0.17 μg/ml. Overall, mean EC50 values of populations from RI-sprayed orchards increased three-, two-, five-, and twofold between 2006 and 2008 for azoxystrobin, pyraclostrobin, boscalid, and pyraclostrobin + boscalid, respectively. A subset of 10 M. fructicola isolates representing low and high EC50 values for azoxystrobin, boscalid, and boscalid + pyraclostrobin was selected for a detached fruit assay to determine disease incidence and severity following protective treatments of formulated RI fungicides at label rates. Brown rot incidence was greater than 50% when fruit were inoculated with isolates having EC50 values of 2, 4, and 0.6 μg/ml for azoxystrobin, boscalid, and pyraclostrobin + boscalid, respectively. Pyraclostrobin failed to control any of the isolates tested in detached fruit assays. Based on minimum inhibitory concentration and brown rot incidence data, we recommend using 3 and 0.75 μg/ml as discriminatory doses to distinguish between sensitive isolates and those with reduced sensitivity to azoxystrobin and pyraclostrobin + boscalid, respectively. Results from our in vitro and in vivo assays indicate a shift toward reduced sensitivity in M. fructicola from the southeastern United States. No cross-resistance was observed between the QoI and the SdhI fungicides, which implies that rotation or tank mixtures of these two chemical classes can be used as a resistance management strategy.

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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