Several Metarhizium Species Produce Ergot Alkaloids in a Condition-Specific Manner

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.

ISOLASI DAN IDENTIFIKASI KAPANG PADA PINDANG BANDENG (Chanos chanos) PRESTO

Ikan pindang adalah salah satu olahan yang sangat disukai oleh masyarakat Indonesia. Hal ini dapat dilihat dari produksi ikan pindang yang setiap tahunnya mengalami peningkatan. Sebagai contoh di Kabupaten Bogor, produksi ikan pindang pada tahun 2013 sebesar 3.643,56 ton, meningkat menjadi 10.334,44ton pada tahun 2015. Ikan pindang disisi lain, sangat mudah mengalami kemunduran mutu disebabkan masih tingginya kadar air, pengemasan yang tidak memenuhi standar serta proses pengolahan yang pada umumnya kurang menerapkan prinsip sanitasi yang baik. Penelitian ini bertujuan untuk mengisolasi dan mengidentifikasi kapang yang tumbuh pada bandeng presto. Sampel Bandeng presto diambil dari CV. Cindy Group. Kapang diisolasi dengan metode pengenceran bertingkat menggunakan media DRBC (Dichloran Rose Bengal Chloramphenicol Agar), kemudian diidentifikasi secara morfologi menggunakan media Malt Extract Agar dan Czapek’s Yeast Extract Agar. Nilai Aktivitas air (aw) bandeng presto memiliki kisaran rata-rata 0,96 – 0,97. Secara makroskopis terlihat adanya pertubuhan kapang pada permukaan ikan bandeng presto setelah penyimpanan selama 3 hari pada suhu ruang (20-250C). Sebanyak 5 isolat kapang diisolasi dari ikan pindang sampel bandeng presto. Hasil identifikasi secara mikroskopis diketahui bahwa kapang yang tumbuh ada ikan pindang tersebut adalah spesies Penicillium citrinum, Eurotium chevalieri, Fusarium solani, Fusarium sp, dan Cladosporium sp. Kadar aw ikan pindang resto yang masih tinggi (0,96-0,97) menyebabkan ikan pindang mengalami pembusukan yang diakibatkan oleh bakteri.

Comprehensive Description of Fusarium graminearum Pigments and Related Compounds

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.

Which Microbial Growth Model Best Fits to Fusarium graminearum?

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.

Comprehensive Description of Fusarium graminearum Pigments and Related Compounds

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.

The Use of Colors as an Alternative to Size in Mold Growth Studies

Size-based fungal growth studies have limitations. For example, the growth in size stops in closed systems once it reaches the borders and poorly describes the metabolic status, especially in the stationary phase. This might lead mycotoxin studies to unrealistic results. Color change could be a viable alternative as pigments are results of the mold’s metabolic activity. This study aimed to verify the possibility of using gray values and the RGB system to analyze the growth of Fusarium graminearum. It consisted color and area measurement using the ImageJ software for specimens grown in yeast extract agar (YEA). The results suggest the usability of color and gray values as reliable tools to analyze the growth of F. graminearum.

Pertumbuhan Fusarium verticillioides, Aspergillus flavus, dan Eurotium chevalieri pada Berbagai Media

Fusarium verticillioides, Aspergillus flavus, dan Eurotium chevalieri merupakan cendawan perusak bahan pangan yang ditemukan pada saat bahan pangan belum dipanen atau setelah bahan pangan dipanen. Pertumbuhan ketiga cendawan ini sangat dipengaruhi oleh nutrisi yang terkandung pada media tumbuh. Penelitian ini bertujuan untuk membandingkan pertumbuhan Fusarium verticillioides, Aspergillus flavus, dan Eurotium chevalieri pada beberapa media untuk isolasi dan identifikasi. Ketiga cendawan tersebut ditumbuhkan pada media yang berbeda yaitu Chloramphenicol Peptone Agar (DCPA), Dichloran 18% Glycerol Agar (DG18), Czapek Yeast Extract Agar (CYA), Czapek Yeast Extract Agar 20% Sucrose (CY20S), Malt Extract Agar (MEA), dan 25% Glycerol Nitrate Agar (G25N) dan diinkubasi pada suhu + 280C. Pengamatan koloni dilakukan setiap 2 x 24 jam, 4 x 24 jam, dan 6 x 24 jam selanjutnya diameter isolat diukur. Hasil isolasi pertumbuhan dan panjang diameter koloni dari A. Flavus (61 mm) dan E. Chevalieri (45mm) diketahui dapat tumbuh baik pada media DG18, sedangkan F. verticillioides (46 mm) tumbuh baik di media DCPA. Sementara pada media identifikasi A. Flavus (80 mm) dapat tumbuh baik pada media CY20S, sedangkan E. Chevalieri (40 mm) dapat tumbuh baik pada media G25N dan CY20S. Koloni F. verticillioides (62 mm) dapat tumbuh baik di media CYA dan CY20S. ©2017 dipublikasikan oleh Savana Cendana.

Microbiological and Clinical Features of Four Cases of Catheter-Related Infection by Methylobacterium radiotolerans

Four cases of central venous catheter-relatedMethylobacterium radiotoleransinfection are presented here. The patients were all long-term catheter carriers with an underlying diagnosis of leukemia, and they mostly manifested fevers. The isolated bacterial strains all showed far better growth on buffered charcoal yeast extract agar during the initial isolation and/or subcultures than they did on sheep blood or chocolate agar. This microbiological feature may improve the culture recovery of this fastidious pink Gram-negative bacillus that has rarely been isolated in clinical microbiology laboratories.