Project description:Aspergillus flavus and A. parasiticus are two of the most important aflatoxin-producing species that contaminate agricultural commodities worldwide. Both species are heterothallic and undergo sexual reproduction in laboratory crosses. Here, we examine the possibility of interspecific matings between A. flavus and A. parasiticus. These species can be distinguished morphologically and genetically, as well as by their mycotoxin profiles. Aspergillus flavus produces both B aflatoxins and cyclopiazonic acid (CPA), B aflatoxins or CPA alone, or neither mycotoxin; Aspergillus parasiticus produces B and G aflatoxins or the aflatoxin precursor O-methylsterigmatocystin, but not CPA. Only four out of forty-five attempted interspecific crosses between compatible mating types of A. flavus and A. parasiticus were fertile and produced viable ascospores. Single ascospore strains from each cross were isolated and were shown to be recombinant hybrids using multilocus genotyping and array comparative genome hybridization. Conidia of parents and their hybrid progeny were haploid and predominantly monokaryons and dikaryons based on flow cytometry. Multilocus phylogenetic inference showed that experimental hybrid progeny were grouped with naturally occurring A. flavus L strain and A. parasiticus. Higher total aflatoxin concentrations in some F1 progeny strains compared to midpoint parent aflatoxin levels indicate synergism in aflatoxin production; moreover, three progeny strains synthesized G aflatoxins that were not produced by the parents, and there was evidence of putative allopolyploidization in one strain. These results suggest that hybridization is an important diversifying force resulting in the genesis of novel toxin profiles in these agriculturally important species.
Project description:To investigate the roles of epigenetic regulator homologs, heterochromatin protein 1 (HepA) and a putative methyltransferase (LaeA), in the citric acid produciton by Aspergillus luchuensis mut. kawachii, we constructed the ΔhepA and ΔlaeA strains. We then performed gene expression profiling analysis using data obtained from RNA-seq of Aspergillus luchuensis mut. kawachii control, ΔhepA, and ΔlaeA strains.
Project description:Genomic DNA from five strains, Aspergillus fumigatus Af71, Aspergillus fumigatus Af294, Aspergillus clavatus, Neosartorya fenneliae, and Neosartorya fischeri, were co-hybridized with that of Aspergillus fumigatus Af293 and compared.
Project description:The filamentous fungus Aspergillus oryzae is an important microbial cell factory for industrial production of useful enzymes, such as α-amylase. In order to optimize the industrial enzyme production process, there is a need to understand fundamental processes underlying protein production, here under how protein production links to metabolism through global regulatory structures. In this study, two α-amylase-producing strains of A. oryzae, a wild type strain and a transformant strain containing additional copies of the α-amylase gene, were characterized at a systematic level. Based on integrated analysis of ome-data together with genome-scale metabolic network and flux calculation, we identified key genes, key enzymes, key proteins, and key metabolites involved in the processes of protein synthesis and secretion, nucleotide metabolism, and amino acid metabolism that can be the potential targets for improving industrial protein production. Keywords: Two Aspergillus oryzae strains and two different carbon sources
Project description:Transcriptome analysis of non-ochratoxigenic Aspergillus carbonarius strains and interactions with other ochratoxigenic black aspergilli
Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. Keywords: comparative genomic indexing analysis
Project description:Genome sequence data results are reported from experimental and bioinfomatic work using the technique 'Bulk Segregant Analysis' to determine the genetic basis of observed resistance to the azole antifungal compound itraconazole in the opportunistic fungal pathogen Aspergillus fumigatus.
Project description:To identify peanut Aspergillus-interactive and Aspergillus-resistance genes, we carried out a large scale peanut Expressed Sequence Tag (EST) project followed by a peanut microarray study. For expression profiling, resistant and susceptible peanut cultivars were infected with a mixture of Aspergillus flavus and parasiticus spores. Microarray analysis identified 65 and 1 genes in resistant (C20) and susceptible (TF) cultivars, respectively, that were up-regulated in response to Aspergillus infection. In addition we identified 40 putative Aspergillus-resistance genes that were constitutively up-expressed in the resistant cultivar in comparison to the susceptible cultivar. Some of these genes were homologous to peanut, corn, and soybean genes previously shown to confer resistance to fungal infection. These results provide a comprehensive genome-scale platform for future studies focused on developing Aspergillus-resistant peanut cultivars through conventional breeding, marker-assisted breeding, or biotechnological methods by gene manipulation.
Project description:Aspergillus fumigatus mutant strains were collected from bronchoalveolar lavage fluids (BALFs) during acute mouse infection (4 and 12 hours).