The regulation of sclerotium initiation in Sclerotium rolfsii by glucose and cyclic AMP

1983 ◽  
Vol 29 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Y. Hadar ◽  
M. Pines ◽  
I. Chet ◽  
Y. Henis
Keyword(s):  
Culture Medium ◽  
Sclerotium Rolfsii ◽  
Fungal Growth ◽  
Maximal Level ◽  
Glucose Addition ◽  
Glucose Depletion ◽  
Endogenous Substrates ◽  
Further Development ◽  
Wall Components ◽  
Glucose Supplementation

Sclerotium rolfsii, grown in a shaken submerged culture, developed a potential for the formation of sclerotia. This potential was inhibited by the presence of glucose in the culture medium. The cultures were capable of producing sclerotia, after transfer to stationary incubation, when glucose was exhausted and the biomass reached its maximal level. The level of adenosine 3′,5′-cyclic monophosphate (cAMP) sharply increased upon glucose depletion and decreased upon glucose addition. Sclerotium rolfsii was grown in a chemostat with glucose of limiting concentration at a dilution rate of 0.05/h. Samples from the chemostat possessed the potential to produce initials when poured into empty Petri plates. Addition of glucose to these plates changed the fungal growth pattern from further differentiation to vegetative growth. Glucose supplementation to clearly differentiated initials did not inhibit further development. It was observed that during morphogenetic events endogenous substrates, e.g., cell wall components, were utilized.

Influence de la monensine sur la croissance et la sécrétion des exopolysaccharides chez le Botrytis cinerea Pers. et le Sclerotium rolfsii Sacc.

1996 ◽  
Vol 42 (9) ◽  
pp. 965-972 ◽  
Author(s):  
Yahya Koulali ◽  
Ahmed Talouizte ◽  
Jean-Louis Fonvieille ◽  
Robert Dargent
Keyword(s):  
Botrytis Cinerea ◽  
Culture Medium ◽  
Sclerotium Rolfsii ◽  
Fungal Growth ◽  
Polymer Composition ◽  
Composition And Structure ◽  
Normal Wall

The addition of various concentrations of monensin (1, 5, and 10 μg/mL) to the culture medium inhibits the fungal growth and perturbs exopolysaccharides secretion, provoking a decrease of production in Botrytis cinerea and an increase in Sclerotium rolfsii. The ionophore induces also modifications in both polymer composition and structure. New monomers were observed in the two species and a decreased branching rate for Sclerotium rolfsii. These modifications show that monensin affects the enzymes responsible for normal wall synthesis and therefore vesicular traffic.Key words: monensin, growth, exopolysaccharides, Botrytis cinerea, Sclerotium rolfsii.

Chemical control of fungal growth and ochratoxin A production by Aspergillus isolated from Moroccan grapes

2018 ◽  
Vol 7 (2) ◽  
pp. 84-91
Author(s):  
Adil Laaziz ◽  
Souad Qjidaa ◽  
Yousra El Hammoudi ◽  
Abdelouahed Hajjaji ◽  
Amina Bouseta
Keyword(s):  
Ochratoxin A ◽  
Radial Growth ◽  
Culture Medium ◽  
Fungal Growth ◽  
Sublethal Concentration ◽  
Agar Culture ◽  
Total Inhibition ◽  
Yeast Autolysate ◽  
Germination And Growth ◽  
Czapek Yeast Autolysate Agar

The aim of this study was to evaluate the effect of three fungicides azoxystrobin (Ortiva), hexaconazole (Hexa) and pyrimethanil (Pyrus) for their ability to inhibit the radial growth and ochratoxin A (OTA) production by five ochratoxigenic strains of Aspergillus carbonarius and A. niger previously iso-lated from Moroccan grapes. Our results showed that, the addition of the fungicides to the Czapek Yeast Autolysate agar culture medium reduced the growth of the ochratoxigenic strains. Pyrimethanil caused total inhibition of spore germination and growth of the five strains, for all dose tested. Where-as hexaconazole totally inhibited the growth of 4 strains and gave growth for the MUCL 49227 strain (2.67 mm/day) at sublethal concentration. The reduction in radial growth was less marked for azoxystrobin, with growth rate varying between 0 and 6.37 mm/day depending on the strain and the azoxystrobin concentration. Analysis of variance showed that the effect of single factors (fungicides, concentration and strain) and their interactions on growth and OTA production were highly significant (P=0.000).These findings suggest that the use of tested fungicides have to potential for reduction in production of OTA.

scholarly journals Selection of filamentous fungi that are resistant to the herbicides atrazine, glyphosate and pendimethalin

2021 ◽  
Vol 43 ◽  
pp. e51656
Author(s):  
Nara Priscila Barbosa Bravim ◽  
Anatércia Ferreira Alves ◽  
José Fábio França Orlanda ◽  
Patricia Barbosa Rodrigues Silva
Keyword(s):  
Filamentous Fungi ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Agricultural Soils ◽  
Culture Media ◽  
Fusarium Verticillioides ◽  
Fungal Growth ◽  
Relative Growth ◽  
Maximum Inhibition ◽  
Selection Of

The objective of the present study was to isolate fungi from agricultural soils and evaluate fungal growth in culture medium contaminated with atrazine, glyphosate and pendimethalin. Filamentous fungi were isolated from agricultural soils and cultured in a modified culture medium containing 0, 10, 20, 50, and 100 μg mL-1 atrazine, glyphosate and pendimethalin for 14 days at 28°C. The fungi that presented optimal and satisfactory growth were plated in Sabouraud culture medium with 4% dextrose and containing the herbicides at concentrations of 0, 10, 20, 50, and 100 μg mL-1 for seven days at 28°C. The mean mycelial growth values were submitted to analysis of variance and the Tukey test (p < 0.05%) for comparison and relative growth determination, and maximum inhibition rates were calculated. The isolated fungi Aspergillus fumigatus, Fusarium verticillioides and Penicillium citrinum were shown to be resistant to atrazine, glyphosate and pendimethalin. F. verticillioides showed higher mean mycelial growth in the culture media contaminated with atrazine and glyphosate than the other two fungi. In the culture medium contaminated with pendimethalin, F. verticillioides, and A. fumigatus presented the highest mean mycelial growth values.

scholarly journals Effective medium for in vitro sprouting of the buds and multiplication of the plantlets, and identification of the fungal contaminant associated with the explants of Gnetum

2021 ◽  
Vol 16 (2) ◽  
pp. 001-013
Author(s):  
Abwe Mercy Ngone ◽  
Lawrence Monah Ndam ◽  
Rita Mungfu Njilar ◽  
Doungous Oumar ◽  
Thomas Eku Njock
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Fungal Growth ◽  
Growth Media ◽  
Fungal Contamination ◽  
Surface Sterilization ◽  
Pure Cultures ◽  
Nodal Cuttings ◽  
Baseline Information

Plant tissue culture requires the optimization of growth media. Gnetum, known locally in Cameroon as “Eru” is an indigenous gymnospermous vegetable with diverse medicinal, nutritional, cultural and socio-economic values. This resource is over-exploited and expected to neighboring countries, resulting to increased scarcity in the forest. Preliminary work on the in vitro culture of nodal cuttings was faced by the problem of fungal contamination. It was therefore necessary to isolate and identify the fungal contaminant, optimize the surface sterilization of field material and compose an appropriate medium for sprouting. Pure cultures of the fungus were obtained and grown on Potato Dextrose Agar (PDA) and Sabouraud Dextrose Agar (SDA). The identification was based on the appearance of the fungal growth on plates and also on the microscopic view. This was affected by the use of keys. Gnetum explants were disinfected with the various concentrations of disinfectants, preceded in some instances by pre-treatments, as well as incorporating fungicides in the culture medium. Two different culture media were employed: the Woody Plant Medium (WPM) and the Murashige and Skoog (MS) based establishment medium (Y-1). Gnetum was found to live in association with a complex of Microsporum species. The level of contamination of cultures was reduced from 100% to 40% when pre-treated before disinfection and even lower to 10% by incorporating fungicides in the medium. Sprouting was observed in WPM. This study provides baseline information on the in vitro propagation of Gnetum and thus opens up avenues for more research to be carried out in this field.

67 The growth and development of invivo-derived dromedary embryos during short-term incubation: Use of embryo holding medium and the effect of embryonic morphology

2021 ◽  
Vol 33 (2) ◽  
pp. 140
Author(s):  
B. Asadi ◽  
F. Seyedasgari
Keyword(s):  
Growth And Development ◽  
Culture Medium ◽  
Calf Serum ◽  
Daily Basis ◽  
Developmental Competence ◽  
Dromedary Camel ◽  
Short Term ◽  
Experimental Media ◽  
Further Development ◽  
Short Term Culture

Production of invivo embryos for transfer in dromedary camel is a well-established practice, whereas freezing of these embryos is still an ongoing challenge. A common approach in evaluation of freeze–thawing method is achieved by studying invitro development of frozen–thawed embryos. However, not much is known about the development pattern of fresh dromedary embryos during incubation. The objectives of this study were to evaluate the usefulness of commercial holding media for easy short-term culture of these embryos and to provide preliminary insights on the growth and development of hatched blastocysts with different shapes. Recovered hatched blastocysts from superovulated donors were graded as transferable and non-transferable. Embryos with significant folding or crinkliness were further categorized as collapsed, whereas those with a round or oval appearance were categorized as spherical. Culture was performed in 500-μL drops at 38.5°C, 5% O2, 0–6% CO2, and maximum humidity in groups of 2 to 4. The 4 experimental media included culture medium (CM; TCM-199, 10% fetal calf serum (FCS), 0.3mM sodium pyruvate, 2.2mg mL−1 sodium bicarbonate), serum-supplemented holding medium (SSH; Syngro+10% FCS), serum-free holding medium (Syngro) and V-Onestep (Vitromed). In experiment 1, a total of 36 embryos were assigned to 4 groups and further development of the embryos was monitored up to 96h by morphological evaluations, identifying static and degenerating embryos on daily basis. In experiment 2, a total of 16 spherical and 16 collapsed embryos were cultured in SSH and CM and two-thirds of the culture drop was replaced with fresh medium at 72h. The proportion of developing embryos and their size expansion was compared between treatments by Fisher’s test and Mann–Whitney U test, respectively. Statistically similar proportions of embryos continued to develop in all media within the first 48h despite a numeric advantage in CM group; at 72h, the proportion of growing embryos was significantly higher in CM (77.8%) and SSH (66.6%) compared with SFH (11.1%) and OneStep (22.2%) (P&lt;0.05). None of the embryos in SFH and only 1 embryo in the V-Onestep group survived beyond 72h, whereas 3/9 embryos in SSH and 7/9 embryos in CM continued to expand. In experiment 2, the proportion of spherical embryos that developed was higher compared with their collapsed counterparts (8/8 in both groups vs. 5/8 and 4/8 in CM and SSH, respectively) at 24h. However, remaining collapsed embryos grew and expanded at similar rates to spherical ones in each group (P&gt;0.05). Replacing the medium did not favour continuation of embryonic growth in SSH beyond 72 h; only 5/16 embryos survived to 96h compared with 12/16 in CM. In conclusion, serum-supplemented commercial holding preparations provide comparable results to culture medium for short-term incubation of invivo dromedary embryos. Natural collapsing of hatched blastocysts might be associated with lower developmental competence.

scholarly journals In vitro establishment of Bambusa oldhamii Munro from field-grown matrices and molecular identification of endophytic bactéria

2019 ◽  
Vol 49 ◽  
Author(s):  
Ana Paula de Azevedo Pasqualini ◽  
Gabriela Xavier Schneider ◽  
Hugo Pacheco de Freitas Fraga ◽  
Luiz Antonio Biasi ◽  
Marguerite Quoirin
Keyword(s):  
Molecular Identification ◽  
Culture Medium ◽  
Bacterial Isolate ◽  
Fungal Growth ◽  
Endophytic Bacterium ◽  
Liquid Culture Medium ◽  
Rdna Sequencing ◽  
In Vitro Establishment ◽  
Bambusa Oldhamii

ABSTRACT In plant micropropagation, the establishment stage is difficult, due to the presence of microorganisms in tissues from field-grown matrices, especially for bamboo. This study aimed to establish an efficient asepsis protocol for Bambusa oldhamii explants from field plants, as well as to carry out the molecular identification of a possible endophytic bacterial isolate. The explants were exposed to 70 % alcohol, 1 % sodium hypochlorite (NaOCl), 0.1 % mercuric chloride (HgCl2), thiophanate-methyl (Cercobin®) and chlorhexidine digluconate (2 % Riohex®) in different combinations, and introduced into Murashige and Skoog culture medium (solid or liquid), supplemented or not with 4 mL L-1 of Plant Preservative Mixture (PPMTM), totaling seven treatments. The asepsis and immersion of the explants in the liquid culture medium containing 4 mL L-1 of PPMTM visually inhibited the bacterial and fungal growth, allowed the development of shoots with a mean length of 2.2 cm and posterior subcultures, being the best treatment used for the in vitro establishment of B. oldhamii. The molecular identification of an endophytic bacterium performed by 16S rDNA sequencing allowed to identify the bacterial isolate as Ralstonia sp., with 100 % of similarity, and the phylogenetic analysis grouped it with Ralstonia pickettii. In addition, the bacterial isolate showed to be sensitive to 4 mL L-1 of PPMTM by the minimum inhibitory concentration test.

Purification and properties of ι-carrageenase from a marine bacterium

1984 ◽  
Vol 30 (12) ◽  
pp. 1500-1506 ◽  
Author(s):  
C. W. Greer ◽  
W. Yaphe
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Gradient Centrifugation ◽  
Hydrophobic Interaction Chromatography ◽  
Apparent Molecular Weight ◽  
Sucrose Density Gradient ◽  
Resonance Spectroscopy ◽  
Sucrose Density Gradient Centrifugation ◽  
Purification And Properties ◽  
Wall Components

An ι-carrageenase has been purified from the cell-free culture medium of a marine bacterium grown in ι-carrageenan. The enzyme hydrolyzes the β1 → 4 linkages in ι-carrageenan; the major end products, as identified by 13C nuclear magnetic resonance spectroscopy, are ι-neocarratetraose sulfate and ι-neocarrahexaose sulfate. The enzyme was purified by fractionation on Sephacryl S-200 in 2.0 M NaCl and hydrophobic interaction chromatography on Phenyl-Sepharose CL-4B. The purified enzyme had an apparent molecular weight of 57 000, and optimum activity was expressed at pH 8.0, 40 °C, in 0.1 M Na+. The enzyme was stable for at least 6 months at 4 °C in 1.0 M NaCl. Removal of the salt, freezing, or lyophilization destroyed enzyme activity. Membrane fractions, prepared by discontinuous sucrose density gradient centrifugation, also exhibited ι-carrageenase activity. Properties of ι-carrageenase suggest an association with cell wall components.

scholarly journals A Basidiomycete Fungus Responsible for Fresh Mushroom Off-Flavour in Wines: Crustomyces subabruptus, (Bourdot & Galzin) Jülich 1978

OENO One ◽  
2021 ◽  
Vol 55 (3) ◽  
pp. 283-298
Author(s):  
Eric Meistermann ◽  
Stéphanie Villaumé ◽  
Delphine Goffette ◽  
Corinne Trarieux ◽  
Morvan Coarer ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Culture Medium ◽  
Fungal Growth ◽  
Grape Juice ◽  
Warm Environment ◽  
Its Regions ◽  
The Subject ◽  
Basidiomycete Fungus

Grape rot can cause organoleptic deviations in wines, including the aroma of fresh mushrooms; one of the molecules responsible for this is 1-octen-3-one. The bunches affected by this defect are often contaminated by Botrytis cinerea; however, they may also contain a whitish mycelium that cannot be attributed to B. cinerea. This additional fungal growth is the subject of this study.  Several isolations of this fungus were carried out on grape bunches from different vineyards in the French Alsace and Champagne regions using a culture medium containing an anti-Botrytis fungicide (Boscalid). The sequencing of the ITS regions showed that most isolations corresponded to Crustomyces subabruptus (Bourdot & Galzin; Jülich 1978), an endophyte basidiomycete. Contamination tests carried out on bunches and grape juice with this fungus confirmed its responsibility for the appearance of fresh mushroom defects in wines, and showed that it has the capacity to produce large quantities of 1-octen-3-one in a wet and warm environment. The results of this study suggest that this basidiomycete is responsible for fresh mushroom aromas in wines.

Chitin as a Measure of Mold Contamination of Agricultural Commodities and Foods†

1996 ◽  
Vol 59 (1) ◽  
pp. 73-81 ◽  
Author(s):  
M. A. COUSIN
Keyword(s):  
High Performance ◽  
Near Infrared ◽  
Degradation Products ◽  
Fungal Growth ◽  
Dry Weight ◽  
Animal Tissues ◽  
Fungal Cell ◽  
New Methods ◽  
Assay Time ◽  
Wall Components

Chitin is a polysaccharide of β-(1→4)-linked 2-acetamido-2-deoxy-d-glucose (N-acetyl-d-glucosamine) that is found in the cell walls of fungi. In an effort to develop new methods to detect fungi in plant and animal tissues, chemical analyses based on fungal cell wall components have been evaluated. Chitin is not present in plant or most food animal tissues; therefore, the entire sample can be hydrolyzed and analyzed for fungal chitin. Acid, alkaline, and enzymatic hydrolysis have been used to cleave the β-(1→4)-glycosidic bond to produce glucosamine, chitosan, or N-acetylglucosamine. The major methods used to analyze these degradation products have included colorimetry; chromatography (gas chromatography, high performance liquid chromatography, amino acid analysis); microscopy, using fluorescent, nonfluorescent or immunofluorescent dyes; near-infrared spectroscopy; and titrametric assays. Chitin has been used to estimate and quantify fungal growth in plants, wood, grains, hay, and foods. There was an increase in the chitin content as the mold increased; however, the chitin assay showed more variability than other assays for detecting fungal contamination. The future use of the chitin assay will depend upon improvements in sensitivity, assay time, simplified methodology and equipment, and development of reliable conversion factors for converting chitin to fungal dry weight.

Sign in / Sign up

Export Citation Format

Share Document