Culture Conditions Control Expression of the Genes for Aflatoxin and Sterigmatocystin Biosynthesis in Aspergillus parasiticus and A. nidulans

1998 ◽  
Vol 64 (6) ◽  
pp. 2275-2277 ◽  
Author(s):  
Guo Hong Feng ◽  
Thomas J. Leonard
Keyword(s):  
Gene Expression ◽  
High Temperature ◽  
Aspergillus Nidulans ◽  
Expression Pattern ◽  
Polyketide Synthase ◽  
Aspergillus Parasiticus ◽  
Culture Conditions ◽  
Transcript Expression ◽  
Aflatoxin Biosynthesis ◽  
Homologous Genes

ABSTRACT High temperature and nitrate supported gene expression for sterigmatocystin biosynthesis in Aspergillus nidulans; ammonium did not. Homologous genes for aflatoxin biosynthesis inA. parasiticus showed the opposite transcript expression pattern, suggesting that the two mycotoxins are regulated differently. The aflR gene is postulated to require additional genetic elements to effect its own activation by the different culture conditions. A patulin polyketide synthase (PKS) gene was found to be regulated differently than the aflatoxin PKS. Thus, the biosyntheses of structurally similar compounds in these two fungi appear to be regulated very differently.

Abstract P144: Bioinformatic Profiling of the Transcriptional Response of Adult Porcine Bone Marrow Stem Cell during Exposure to Hypoxia

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Suna Wang ◽  
Yifu Zhou ◽  
Xiuli Xu ◽  
Timothy Hunt ◽  
Robert F Hoyt ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Expression Pattern ◽  
Gene Expression Pattern ◽  
Transcriptional Response ◽  
Culture Conditions ◽  
Large Animal Model ◽  
Homologous Gene ◽  
Large Animal ◽  
Gene Search

Background: Cell-based transplantation therapy in a large animal model has been shown to improve angiogenesis and function of ischemic myocardium. These improvements may be due to the endothelial progenitor cells from bone marrow derived stem cells (BMC) generated under ischemic or hypoxic conditions. However the molecular activities of porcine BMC (PBMC) are largely unknown. Thus, a comprehensive gene expression pattern for PBMC is needed to advance the preclinical work necessary for future human treatment. Methods: Fifteen PBMC were cultured in the medium of EGM 2 for 4 weeks, and then incubated either in a monitored hypoxic chamber (1% O2, 5% CO2) (H) or in normal culture conditions (normoxia, N) for 6, 12, 24 and 48 hrs. Twenty RNAs comprising 5 Ns and 15 Hs (6, 12 and 24hr) were hybridized to Affymetrix Porcine arrays. An additional 40 samples were prepared for data confirmation by qRTPCR and Western blot. Data normalization and pattern recognition in each of these subgroups were achieved using R package 2.4 and GeneSpringGX. Homologous gene search and functional classification based on NCBI Pig Genomic Resources and DAVID Bioinformatics Resources 2007. Results: Significant gene expression levels among the four groups were identified. The patterns of three hypoxia (H) groups were clearly distinct from that of normoxia (N) group. However, the expression pattern of 12hr H was more similar to 24hr H than that of 6hr H. Of 23,928 probes, 394 genes were statistically regulated rapidly in 6hr Hs vs. Ns, including HIF2alpha, VEGFA, PDGFA, ANGPT2, CXCL14 and PGD. Only 182 genes were modulated in 12hr Hs, but 84% (152/182) of the genes appeared either with 6hr or 24hr H groups. 227 genes were significantly over- or down- regulated in 24hr Hs, among the 94 genes were overlapped with 6hr and 12hr Hs. Notably, the 94 genes were the most differentially modulated in all three H groups, some of the genes were known involving in the processes of hypoxic stress, response to inflammatory, wounding, apoptosis and angiogenesis. The 94 genes are considered as hypoxic targets for further study. Conclusions: Our results confirmed the role of several genes involved in hypoxic or ischemic states, and captured a set of genes that associated the PBMC response to hypoxic or ischemic surroundings.

scholarly journals Differential Modulation of Heat-Inducible Genes Across Diverse Genotypes and Molecular Cloning of a sHSP From Pearl Millet [Pennisetum glaucum (L.) R. Br.]

2021 ◽  
Vol 12 ◽  
Author(s):  
S. Mukesh Sankar ◽  
C. Tara Satyavathi ◽  
Sharmistha Barthakur ◽  
Sumer Pal Singh ◽  
C. Bharadwaj ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Heat Shock ◽  
Expression Pattern ◽  
Pearl Millet ◽  
Temperature Stress ◽  
Expression Profiling ◽  
High Temperature Stress ◽  
Transcript Expression

The survival, biomass, and grain yield of most of the crops are negatively influenced by several environmental stresses. The present study was carried out by using transcript expression profiling for functionally clarifying the role of genes belonging to a small heat shock protein (sHSP) family in pearl millet under high-temperature stress. Transcript expression profiling of two high-temperature-responsive marker genes, Pgcp70 and PgHSF, along with physio-biochemical traits was considered to screen out the best contrasting genotypes among the eight different pearl millet inbred lines in the seedling stage. Transcript expression pattern suggested the existence of differential response among different genotypes upon heat stress in the form of accumulation of heat shock-responsive gene transcripts. Genotypes, such as WGI 126, TT-1, TT-6, and MS 841B, responded positively toward high-temperature stress for the transcript accumulation of both Pgcp70 and PgHSF and also indicated a better growth under heat stress. PPMI-69 showed the least responsiveness to transcript induction; moreover, it supports the membrane stability index (MSI) data for scoring thermotolerance, thereby suggesting the efficacy of transcript expression profiling as a molecular-based screening technique for the identification of thermotolerant genes and genotypes at particular crop growth stages. The contrasting genotypes, such as PPMI-69 (thermosusceptible) and WGI-126 and TT-1 (thermotolerant), are further utilized for the characterization of thermotolerance behavior of sHSP by cloning a PgHSP16.97 from the thermotolerant cv. WGI-126. In addition, the investigation was extended for the identification and characterization of 28 different HSP20 genes through a genome-wide search in the pearl millet genome and an understanding of their expression pattern using the RNA-sequencing (RNA-Seq) data set. The outcome of the present study indicated that transcript profiling can be a very useful technique for high-throughput screening of heat-tolerant genotypes in the seedling stage. Also, the identified PgHSP20s genes can provide further insights into the molecular regulation of pearl millet stress tolerance, thereby bridging them together to fight against the unpredicted nature of abiotic stress.

scholarly journals Aflatoxin Biosynthesis Cluster Gene cypA Is Required for G Aflatoxin Formation

2004 ◽  
Vol 70 (11) ◽  
pp. 6518-6524 ◽  
Author(s):  
Kenneth C. Ehrlich ◽  
Perng-Kuang Chang ◽  
Jiujiang Yu ◽  
Peter J. Cotty
Keyword(s):  
Polyketide Synthase ◽  
Aspergillus Parasiticus ◽  
Amino Acid Identity ◽  
Gibberella Zeae ◽  
Aflatoxin Biosynthesis ◽  
P450 Monooxygenase ◽  
Pathway Gene ◽  
Polyketide Synthase Gene ◽  
Aspergillus Nomius ◽  
Cluster Gene

ABSTRACT Aspergillus flavus isolates produce only aflatoxins B1 and B2, while Aspergillus parasiticus and Aspergillus nomius produce aflatoxins B1, B2, G1, and G2. Sequence comparison of the aflatoxin biosynthesis pathway gene cluster upstream from the polyketide synthase gene, pksA, revealed that A. flavus isolates are missing portions of genes (cypA and norB) predicted to encode, respectively, a cytochrome P450 monooxygenase and an aryl alcohol dehydrogenase. Insertional disruption of cypA in A. parasiticus yielded transformants that lack the ability to produce G aflatoxins but not B aflatoxins. The enzyme encoded by cypA has highest amino acid identity to Gibberella zeae Tri4 (38%), a P450 monooxygenase previously shown to be involved in trichodiene epoxidation. The substrate for CypA may be an intermediate formed by oxidative cleavage of the A ring of O-methylsterigmatocystin by OrdA, the P450 monooxygenase required for formation of aflatoxins B1 and B2.

Increased sensitivity of Aspergillus flavus and Aspergillus parasiticus aflatoxin biosynthesis polyketide synthase mutants to UVB light

2010 ◽  
Vol 3 (3) ◽  
pp. 263-270 ◽  
Author(s):  
K. Ehrlich ◽  
Q. Wei ◽  
D. Bhatnagar
Keyword(s):  
Aspergillus Flavus ◽  
Polyketide Synthase ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Contamination ◽  
Aflatoxin Biosynthesis ◽  
Increased Sensitivity ◽  
Isogenic Mutants

One strategy to reduce aflatoxin contamination of maize and cottonseed is to introduce spores of non-aflatoxigenic strains as competitors. Using isogenic mutants we show that, upon 5 or 20 min exposure to 302 nm (UVB) light, the viability of conidia of Aspergillus flavus and Aspergillus parasiticus mutants lacking the ability to accumulate any aflatoxin precursor metabolite is reduced five-fold compared to that of aflatoxin-producing strains or pigmented mutants that accumulate aflatoxin precursors. This result suggests that the long-term viability of introduced non-aflatoxigenic competitor strains may be lower than that of natural aflatoxin-producing isolates when exposed to sunlight.

Establishing Standard Protocols for Bacterial Culture in Biological Research in Canisters (BRIC) Hardware

2020 ◽  
Vol 4 (2) ◽  
pp. 58-69 ◽  
Author(s):  
Patricia Fajardo-Cavazos ◽  
Wayne L. Nicholson
Keyword(s):  
Gene Expression ◽  
Bacterial Culture ◽  
Culture Conditions ◽  
Media Culture ◽  
Ground Control ◽  
Biological Research ◽  
Confounding Factors ◽  
Cross Experiment ◽  
Spaceflight Experiments ◽  
Control Samples

AbstractThe NASA GeneLab Data System (GLDS) was recently developed to facilitate cross-experiment comparisons in order to understand the response of microorganisms to the human spaceflight environment. However, prior spaceflight experiments have been conducted using a wide variety of different hardware, media, culture conditions, and procedures. Such confounding factors could potentially mask true differences in gene expression between spaceflight and ground control samples. In an attempt to mitigate such confounding factors, we describe here the development of a standardized set of hardware, media, and protocols for liquid cultivation of microbes in Biological Research in Canisters (BRIC) spaceflight hardware, using the model bacteria Bacillus subtilis strain 168 and Staphylococcus aureus strain UAMS-1 as examples.

Mechanical culture conditions effect gene expression

2001 ◽  
Author(s):  
J. Love ◽  
T. Hammond ◽  
P. Allen ◽  
L. Cubano ◽  
T. Baker ◽  
...  
Keyword(s):  
Gene Expression ◽  
Culture Conditions ◽  
Effect Gene
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