Eukaryotes have evolved highly conserved vesicle transport machinery to deliver proteins the vacuole. In this study we show that filamentous fungus Aspergillus parasiticus employs delivery system perform new cellular functions, synthesis, compartmentalization, and export of aflatoxin; secondary metabolite is one most potent naturally occurring carcinogens known. Here a pure vesicle-vacuole fraction isolated from A. under aflatoxin-inducing conditions converts sterigmatocystin, late...

In filamentous fungi, several lines of experimental evidence indicate that secondary metabolism is triggered by oxidative stress; however, the functional and molecular mechanisms mediate this association are unclear. The basic leucine zipper (bZIP) transcription factor AtfB, a member bZIP/CREB family, helps regulate conidial tolerance to stress. work, we investigated role AtfB in connection between stress response fungus Aspergillus parasiticus. This well characterized model organism...

Abstract The mycotoxin aflatoxin is a secondary metabolite and potent human carcinogen. We investigated one mechanism that links stress response with coordinate activation of genes involved in biosynthesis A spergillus parasiticus . Electrophoretic mobility shift assays demonstrated AtfB , basic leucine zipper ( bZIP ) transcription factor, master co‐regulator binds promoters early fas‐1 ), middle ver‐1 late omtA biosynthetic as well stress‐response (mycelia‐specific cat1...

The 27 genes involved in aflatoxin biosynthesis are clustered within a 70 kb region the Aspergillus parasiticus genome. Using chromatin immunoprecipitation, we demonstrated positive correlation between initiation and spread of histone H4 acetylation promoters onset accumulation proteins aflatoxin. Histone pksA (encodes an 'early' biosynthetic pathway enzyme) promoter peaked at 30 h, prior to increased omtA ordA (encode 'late' enzymes) detected 40 h. specific order which pksA, ver-1 'middle'...

ABSTRACT Survival of fungal species depends on the ability these organisms to respond environmental stresses. Osmotic stress or high levels reactive oxygen (ROS) can cause in fungi resulting growth inhibition. Both eukaryotic and prokaryotic cells have developed numerous mechanisms counteract survive presence ROS. In many fungi, HOG signaling pathway is crucial for oxidative response as well osmotic response. This study revealed that while only slightly affected by master regulator veA ,...

Aflatoxin biosynthesis in the filamentous fungus Aspergillus parasiticus involves a minimum of 21 enzymes, encoded by genes located 70 kb gene cluster. For aflatoxin to be completed, required enzymes must transported specialized early and late endosomes called aflatoxisomes. Of particular significance, seven biosynthetic are P450/monooxygenases which catalyze reactions that can produce reactive oxygen species (ROS) as byproducts. Thus, oxidative pathway could potentially an additional source...

ABSTRACT Filamentous fungi synthesize bioactive secondary metabolites with major human health and economic impacts. Little is known about the mechanisms that mediate export of these to cell exterior. Aspergillus parasiticus synthesizes aflatoxin, a metabolite one most potent naturally occurring carcinogens known. We previously demonstrated aflatoxin synthesized compartmentalized in specialized vesicles called aflatoxisomes subcellular organelles also play role process. In current study, we...

Filamentous fungi in the genus Aspergillus produce a variety of natural products, including aflatoxin, most potent naturally occurring carcinogen known. Aflatoxin biosynthesis, one highly characterized secondary metabolic pathways, offers model system to study metabolism eukaryotes. To control or customize biosynthesis products we must understand how integrates into overall cellular network. By applying metabolomics approach analyzed volatile compounds synthesized by parasiticus an attempt...

Abstract Increase photorespiration and optimising intrinsic water use efficiency are unique challenges to photosynthetic carbon fixation at elevated temperatures. To determine how plants can adapt facilitate high rates of temperatures while also maintaining water‐use efficiency, we performed in‐depth gas exchange biochemical assays the C 3 extremophile, Rhazya stricta . These results demonstrate that R. supports higher under these correlate with increased activity key photorespiratory...

ABSTRACT The filamentous fungi Aspergillus parasiticus and flavus produce the carcinogenic secondary metabolite aflatoxin on susceptible crops. These species differ in quantity of aflatoxins B 1 , 2 G produced culture, ability to mycotoxin cyclopiazonic acid, morphology mycelia conidiospores. To understand genetic basis for differences biochemistry morphology, we conducted next-generation sequence (NGS) analysis A. strain SU-1 genome comparative gene expression (RNA [RNA Seq]) NRRL 3357...

Fungal basic leucine zipper (bZIP) transcription factors mediate responses to oxidative stress. The ability regulate stress response pathways in Aspergillus spp. was postulated be an important virulence-associated cellular process, because it helps establish infection humans, plants, and animals. Previous studies have demonstrated that the fungal factor AtfB encodes a protein is associated with resistance asexual conidiospores, binds promoters of several genes. Here, we conducted gene...

The level of aflatoxin accumulation in the filamentous fungus Aspergillus parasiticus is modulated by a variety environmental cues. presence glucose (a preferred carbon source) liquid and solid minimal salts (GMS) growth media strongly stimulated accumulation. Peptone non-preferred peptone (PMS) only low levels Glucose transcription structural genes ver-1 nor-1 to similar intermediate GMS, while on media, was 20-fold higher than nor-1. PMS very or non-detectable both genes. Electrophoretic...

Aspergillus parasiticus is one primary source of aflatoxin contamination in economically important crops. To prevent the potential health and economic impacts contamination, our goal to develop practical strategies reduce synthesis on susceptible One focus identify biological environmental factors that regulate manipulate these control biosynthesis field or during crop storage. In current study, we analyzed effects aspergillus volatiles growth, development, biosynthesis, promoter activity...

Aflatoxin is among the most potent naturally occurring carcinogens known. Previous studies demonstrated that endosomes in filamentous fungus Aspergillus parasiticus carry enzymes catalyze final two steps aflatoxin synthesis, and these structures also play a role storage export. We hypothesized house complete functional biosynthetic pathway. To address this hypothesis, we purified cellular fraction containing endosomes, transport vesicles, vacuoles (V fraction) from A. grown under inducing...