scholarly journals Comprehensive Description of Fusarium graminearum Pigments and Related Compounds

Author(s):  
Edgar Cambaza

Several studies explore in depth the biochemistry and genetics of the pigments present in Fusarium graminearum but there is a need to discuss about their relationship with the mold’s observable surface color pattern variation throughout its lifecycle. Furthermore, they require basic cataloguing and description of their major features known so far. Colors are a viable alternative to size measurement in growth studies. When grown on yeast extract agar (YEA) at 25 °C, F. graminearum initially exhibits a whitish mycelium, developing into a yellow-orange mold by the sixth day and then turning into wine-red. The colors are likely due to accumulation of the golden yellow polyketide aurofusarin and the red rubrofusarin, but the carotenoid neurosporaxanthin possibly play also a major role in the yellow or orange coloration. Torulene might contribute for red tones but it perhaps ends up being converted into neurosporaxanthin. Culmorin is also present but it does not contribute for the color, though it was initially isolated in pigment studies, and there is the 5-deoxybostrycoidin-based melanin, but it occurs mostly in the teleomorph’s perithecium. There is still a need to chemically quantify the pigments throughout the lifecycle, analyze their relationships and how much each impacts F. graminearum surface color.

Foods ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 165 ◽  
Author(s):  
Edgar Cambaza

Several studies have explored in depth the biochemistry and genetics of the pigments present in Fusarium graminearum, but there is a need to discuss their relationship with the mold’s observable surface color pattern variation throughout its lifecycle. Furthermore, they require basic cataloguing, including a description of their major features known so far. Colors are a viable alternative to size measurement in growth studies. When grown on yeast extract agar (YEA) at 25 °C, F. graminearum initially exhibits a whitish mycelium, developing into a yellow-orange mold by the sixth day and then turning into wine-red. The colors are likely due to accumulation of the golden yellow polyketide aurofusarin and the red rubrofusarin, but the carotenoid neurosporaxanthin also possibly plays a major role in the yellow or orange coloration. Torulene might contribute to red tones, but it perhaps ends up being converted into neurosporaxanthin. Culmorin is also present, but it does not contribute to the color, though it was initially isolated in pigment studies. Additionally, there is the 5-deoxybostrycoidin-based melanin, but it mostly occurs in the teleomorph’s perithecium. There is still a need to chemically quantify the pigments throughout the lifecycle, and analyze their relationships and how much each impacts F. graminearum’s surface color.


Author(s):  
Edgar Cambaza

Fusarium graminearum causes head blight in wheat and corn, and produces chemicals harmful for humans and other animals. It is important to understand how it grows in order to prevent outbreaks. There are 3 well-known growth models for microorganisms and they seem applicable to molds: linear, Gompertz and Baranyi. This study aimed to see which could better represent F. graminearum growth. Three replicates were grown in yeast extract agar (YEA) for 20 days. The Feret’s radius was measured in ImageJ software, and then related to the models. Linear model was the most closely correlated to the actual growth. Thus, considering that it was the most representative of the reality and it is easier to use, it seems to be the best logical choice for F. graminearum growth studies.


Foods ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, aw has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at aw = 0.94, 0.97, and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each aw. After 4, 8, 12, and 16 days, three specimens from each aw were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at aw = 0.99 because at lower aw the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at aw = 0.99, where they presented inverse proportionality.


1983 ◽  
Vol 29 (9) ◽  
pp. 1171-1178 ◽  
Author(s):  
J. D. Miller ◽  
A. Taylor ◽  
R. Greenhalgh

A liquid culture method for the production of deoxynivalenol and related compounds by Fusarium graminearum was developed. Major factors which stimulate the biosynthesis of these compounds include reduced oxygen levels, depletion of carbohydrate in the medium, pH, and possibly a low concentration of an organic nitrogen source. Isolates of F. graminearum were tested for the yields of four trichothecene mycotoxins and zearalenone in this system. The time course of acetyl deoxynivalenol, deoxynivalenol, and zearalenone in the fermentation was measured over a 21-day period against pH, glucose concentration, protein, fungal biomass, and ergosterol. A new ester of deoxynivalenol, 15-acetyl-deoxynivalenol, is reported from North American isolates of F. graminearum.


2004 ◽  
Vol 50 (1) ◽  
pp. 277-280
Author(s):  
M. Vulindlu ◽  
A. Charlett ◽  
S. Surman ◽  
J.V. Lee

Pour and spread plates are the conventional methods of choice for the isolation and enumeration of heterotrophic microorganisms in treated water supplies. The tests are performed at 22°C and 37°C for 72 h and 48 h respectively. Counts at 22°C are associated with pollution of water systems from external sources, while counts at 37°C are used as an indication of treatment plant performance and the deterioration of the general quality of water. Conventional methods using Yeast Extract Agar for a pour plate and R2A agar for a spread plate were compared with the multidose IDEXXTM SimPlate method for the isolation and enumeration of heterotrophic bacteria in water. SimPlate gave a significantly higher count on average than the conventional methods. The R2A method showed the next highest count, being significantly higher than Yeast Extract Agar. In addition, unlike the pour and spread plate methods, SimPlate was easier to use, reduced labour, and the test results were far easier to read.


Zootaxa ◽  
2019 ◽  
Vol 4604 (3) ◽  
pp. 482 ◽  
Author(s):  
DAVID KRÁL ◽  
LUCIE HRŮZOVÁ ◽  
PETR ŠÍPEK ◽  
AHMED IBRAHIM AWALE ◽  
ALI ABDI HURRE ◽  
...  

Pachnoda iskuulka Král, Sommer & Šípek, new species from the Sanaag region of north-eastern Somaliland is described. The new species is compared with the morphologically similar taxa Pachnoda abyssinica abyssinica Reiche, 1847, P. a. meriteti Di Gennaro, 2017, P. massajae Gestro, 1881, and P. werneri Beinhundner, 1992, all of which occur in the Horn of Africa. Relevant diagnostic characters (e.g., dorsal and ventral surface color pattern, male external genitalia) are illustrated. The third instar larva of the new species is described and biological notes are provided. 


2001 ◽  
Vol 64 (7) ◽  
pp. 1030-1034 ◽  
Author(s):  
WILLIE J. TAYLOR ◽  
FRANCES A. DRAUGHON

This study examined the potential for controlling toxigenic Aspergillus flavus and Aspergillus parasiticus by biological means using a myxobacterium commonly found in soil. The ability of Nannocystis exedens to antagonize A. flavus ATCC 16875, A. flavus ATCC 26946, and A. parasiticus NRRL 3145 was discovered. Cultures of aflatoxigenic fungi were grown on 0.3% Trypticase peptone yeast extract agar for 14 days at 28°C. When N. exedens was grown in close proximity with an aflatoxigenic mold, zones of inhibition (10 to 20 mm) developed between the bacterium and mold colony. A flattening of the mold colony on the sides nearest N. exedens and general stunting of growth of the mold colony were also observed. When N. exedens was added to the center of the cross-streak of a mold colony, lysis of the colony by the bacterium was observed after 24 h. Microscopic observations revealed that N. exedens grew on spores, germinating spores, hyphae, and sclerotia of the molds. These results indicate that N. exedens may be a potential biocontrol agent against A. flavus and A. parasiticus.


2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Caroline E. Leadmon ◽  
Jessi K. Sampson ◽  
Matthew D. Maust ◽  
Angie M. Macias ◽  
Stephen A. Rehner ◽  
...  

ABSTRACT Genomic sequence data indicate that certain fungi in the genus Metarhizium have the capacity to produce lysergic acid-derived ergot alkaloids, but accumulation of ergot alkaloids in these fungi has not been demonstrated previously. We assayed several Metarhizium species grown under different conditions for accumulation of ergot alkaloids. Isolates of M. brunneum and M. anisopliae accumulated the lysergic acid amides lysergic acid α-hydroxyethyl amide, ergine, and ergonovine on sucrose-yeast extract agar but not on two other tested media. Isolates of six other Metarhizium species did not accumulate ergot alkaloids on sucrose-yeast extract agar. Conidia of M. brunneum lacked detectable ergot alkaloids, and mycelia of this fungus secreted over 80% of their ergot alkaloid yield into the culture medium. Isolates of M. brunneum, M. flavoviride, M. robertsii, M. acridum, and M. anisopliae produced high concentrations of ergot alkaloids in infected larvae of the model insect Galleria mellonella, but larvae infected with M. pingshaense, M. album, M. majus, and M. guizhouense lacked detectable ergot alkaloids. Alkaloid concentrations were significantly higher when insects were alive (as opposed to killed by freezing or gas) at the time of inoculation with M. brunneum. Roots of corn and beans were inoculated with M. brunneum or M. flavoviride and global metabolomic analyses indicated that the inoculated roots were colonized, though no ergot alkaloids were detected. The data demonstrate that several Metarhizium species produce ergot alkaloids of the lysergic acid amide class and that production of ergot alkaloids is tightly regulated and associated with insect colonization. IMPORTANCE Our discovery of ergot alkaloids in fungi of the genus Metarhizium has agricultural and pharmaceutical implications. Ergot alkaloids produced by other fungi in the family Clavicipitaceae accumulate in forage grasses or grain crops; in this context they are considered toxins, though their presence also may deter or kill insect pests. Our data report ergot alkaloids in Metarhizium species and indicate a close association of ergot alkaloid accumulation with insect colonization. The lack of accumulation of alkaloids in spores of the fungi and in plants colonized by the fungi affirms the safety of using Metarhizium species as biocontrol agents. Ergot alkaloids produced by other fungi have been exploited to produce powerful pharmaceuticals. The class of ergot alkaloids discovered in Metarhizium species (lysergic acid amides) and their secretion into the growth medium make Metarhizium species a potential platform for future studies on ergot alkaloid synthesis and modification.


2010 ◽  
Vol 3 (1) ◽  
pp. 45-48 ◽  
Author(s):  
S. Romero ◽  
M. Alberto ◽  
G. Vaamonde

The aim of the present study was to investigate the gallic acid influence on Aspergillus carbonarius growth and ochratoxin A (OTA) biosynthesis. A mixed inoculum was used in Czapek Yeast Extract Agar and growth and OTA production was observed at 100 to 500 mg/l of the phenolic compound. Slower colony growth rates and longer lag phases were observed with increasing concentration and 500 mg/l was totally inhibitory for A. carbonarius growth. OTA production decrease was observed even at the lower concentration assayed. Gallic acid could be used as a natural antimicrobial for the control of ochratoxigenic A. carbonarius.


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