scholarly journals Identification and Characterization of the Asperthecin Gene Cluster of Aspergillus nidulans

2008 ◽  
Vol 74 (24) ◽  
pp. 7607-7612 ◽  
Author(s):  
Edyta Szewczyk ◽  
Yi-Ming Chiang ◽  
C. Elizabeth Oakley ◽  
Ashley D. Davidson ◽  
Clay C. C. Wang ◽  
...  

ABSTRACT The sequencing of Aspergillus genomes has revealed that the products of a large number of secondary metabolism pathways have not yet been identified. This is probably because many secondary metabolite gene clusters are not expressed under normal laboratory culture conditions. It is, therefore, important to discover conditions or regulatory factors that can induce the expression of these genes. We report that the deletion of sumO, the gene that encodes the small ubiquitin-like protein SUMO in A. nidulans, caused a dramatic increase in the production of the secondary metabolite asperthecin and a decrease in the synthesis of austinol/dehydroaustinol and sterigmatocystin. The overproduction of asperthecin in the sumO deletion mutant has allowed us, through a series of targeted deletions, to identify the genes required for asperthecin synthesis. The asperthecin biosynthesis genes are clustered and include genes encoding an iterative type I polyketide synthase, a hydrolase, and a monooxygenase. The identification of these genes allows us to propose a biosynthetic pathway for asperthecin.

Author(s):  
Obul Reddy Bandapali ◽  
Frederik Teilfeldt Hansen ◽  
Alisha Parveen ◽  
Pradeep Phule ◽  
Emmagouni Sharath Kumar Goud ◽  
...  

Eurotium rubrum is a halophilic marine ascomycete, which can bear the hypersalinities of the Red Sea and proliferate, while most living entities cannot bear this condition. Recently, a 26.2 Mb assembled genome of this fungus had become available. Marine fungi are fascinating organisms capable of harboring several biosynthetic gene clusters (BGCs), which enables them to produce several natural compounds with antibiotic and anticancerous properties. Understanding the BGCs are critically important for the development of biotechnological applications and the discovery of future drugs. There is no knowledge available on the BGCs of this halophilic marine ascomycete. Herein, we set out to explore and characterize BGCs and the corresponding genes from E. rubrum using bioinformatic methods. We deciphered 36 BGCs in the genome of E. rubrum. These 36 BGCs can be grouped into four non-ribosomal peptide synthetase (NRPS) clusters, eight NRPS-like (NRPSL) BGCs, eight type I polyketide synthase (T1PKS), 11 terpene BGCs including one β-lactone cluster, four hybrid BGCs, and two siderophore BGCs. This study is an example of marine genomics application into potential future drug-like compound discovery.


2019 ◽  
Author(s):  
Fabian Panter ◽  
Ronald Garcia ◽  
Angela Thewes ◽  
Nestor Zaburannyi ◽  
Boyke Bunk ◽  
...  

AbstractThe roles of the majority of bacterial secondary metabolites, especially those from uncommon sources are yet elusive even though many of these compounds show striking biological activities. To further investigate the secondary metabolite repertoire of underexploited bacterial families, we chose to analyze a novel representative of the yet untapped bacterial phylum Planctomycetes for the production of secondary metabolites under laboratory culture conditions. Development of a planctomycetal high density cultivation technique in combination with high resolution mass spectrometric analysis revealed Planctomycetales strain 10988 to produce the plant toxin 3,5 dibromo p-anisic acid. This molecule represents the first secondary metabolite reported from any planctomycete. Genome mining revealed the biosynthetic origin of this doubly brominated secondary metabolite and a biosynthesis model for the com-pound was devised. Comparison of the biosynthetic route to biosynthetic gene clusters responsible for formation of polybrominated small aromatic compounds reveals evidence for an evolutionary link, while the compound’s herbicidal activity points towards an ambivalent role of the metabolite in the planctomycetal ecosystem.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Yongjae Lee ◽  
Namil Lee ◽  
Soonkyu Hwang ◽  
Woori Kim ◽  
Yujin Jeong ◽  
...  

AbstractStreptomyces species are gram-positive bacteria with GC-rich linear genomes and they serve as dominant reservoirs for producing clinically and industrially important secondary metabolites. Genome mining of Streptomyces revealed that each Streptomyces species typically encodes 20–50 secondary metabolite biosynthetic gene clusters (smBGCs), emphasizing their potential for novel compound discovery. Unfortunately, most of smBGCs are uncharacterized in terms of their products and regulation since they are silent under laboratory culture conditions. To translate the genomic potential of Streptomyces to practical applications, it is essential to understand the complex regulation of smBGC expression and to identify the underlying regulatory elements. To progress towards these goals, we applied two Next-Generation Sequencing methods, dRNA-Seq and Term-Seq, to industrially relevant Streptomyces species to reveal the 5´ and 3´ boundaries of RNA transcripts on a genome scale. This data provides a fundamental resource to aid our understanding of Streptomyces’ regulation of smBGC expression and to enhance their potential for secondary metabolite synthesis.


2009 ◽  
Vol 191 (10) ◽  
pp. 3415-3419 ◽  
Author(s):  
Hyun Sook Lee ◽  
Yun Jae Kim ◽  
Jung-Hyun Lee ◽  
Sung Gyun Kang

ABSTRACT Two hypothetical genes were functionally verified to be a pyrophosphatase and a PAP phosphatase in Thermococcus onnurineus NA1. This is the first report of the pyrophosphatases and the PAP phosphatases being organized in the gene clusters of the sulfate activation system only in T. onnurineus NA1 and “Pyrococcus abyssi.”


2014 ◽  
Vol 179 ◽  
pp. 10-17 ◽  
Author(s):  
Antonia Gallo ◽  
Benjamin P. Knox ◽  
Kenneth S. Bruno ◽  
Michele Solfrizzo ◽  
Scott E. Baker ◽  
...  

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 483
Author(s):  
Tomohiro Morohoshi ◽  
Yaoki Kamimura ◽  
Nobutaka Someya

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signals in Gram-negative bacteria. Many genes encoding AHL-degrading enzymes have been cloned and characterized in various microorganisms. Coagulase-negative staphylococci (CNS) are present on the skin of animals and are considered low-virulent species. The AHL-lactonase gene homologue, ahlS, was present in the genomes of the CNS strains Staphylococcus carnosus, Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus sciuri. We cloned the candidate ahlS homologue from six CNS strains into the pBBR1MCS5 vector. AhlS from the CNS strains showed a higher degrading activity against AHLs with short acyl chains compared to those with long acyl chains. AhlS from S. sciuri was expressed and purified as a maltose-binding protein (MBP) fusion. Pseudomonas aeruginosa is an opportunistic pathogen that regulates several virulence factors such as elastase and pyocyanin by quorum-sensing systems. When MBP-AhlS was added to the culture of P. aeruginosa PAO1, pyocyanin production and elastase activity were substantially reduced compared to those in untreated PAO1. These results demonstrate that the AHL-degrading activity of AhlS from the CNS strains can inhibit quorum sensing in P. aeruginosa PAO1.


2019 ◽  
Vol 20 (10) ◽  
pp. 2394 ◽  
Author(s):  
Minerva Mata-Rocha ◽  
Angelica Rangel-López ◽  
Elva Jiménez-Hernández ◽  
Blanca Angélica Morales-Castillo ◽  
Carolina González-Torres ◽  
...  

Acute lymphoblastic leukemia is the most common type of childhood cancer worldwide. Mexico City has one of the highest incidences and mortality rates of this cancer. It has previously been recognized that chromosomal translocations are important in cancer etiology. Specific fusion genes have been considered as important treatment targets in childhood acute lymphoblastic leukemia (ALL). The present research aimed at the identification and characterization of novel fusion genes with potential clinical implications in Mexican children with acute lymphoblastic leukemia. The RNA-sequencing approach was used. Four fusion genes not previously reported were identified: CREBBP-SRGAP2B, DNAH14-IKZF1, ETV6-SNUPN, ETV6-NUFIP1. Although a fusion gene is not sufficient to cause leukemia, it could be involved in the pathogenesis of the disease. Notably, these new translocations were found in genes encoding for hematopoietic transcription factors which are known to play an important role in leukemogenesis and disease prognosis such as IKZF1, CREBBP, and ETV6. In addition, they may have an impact on the prognosis of Mexican pediatric patients with ALL, with the potential to be included in the current risk stratification schemes or used as therapeutic targets.


2006 ◽  
Vol 50 (6) ◽  
pp. 1973-1981 ◽  
Author(s):  
Magdalena Stoczko ◽  
Jean-Marie Frère ◽  
Gian Maria Rossolini ◽  
Jean-Denis Docquier

ABSTRACT The diffusion of metallo-β-lactamases (MBLs) among clinically important human pathogens represents a therapeutic issue of increasing importance. However, the origin of these resistance determinants is largely unknown, although an important number of proteins belonging to the MBL superfamily have been identified in microbial genomes. In this work, we analyzed the distribution and function of genes encoding MBL-like proteins in the class Rhizobiales. Among 12 released complete genomes of members of the class Rhizobiales, a total of 57 open reading frames (ORFs) were found to have the MBL conserved motif and identity scores with MBLs ranging from 8 to 40%. On the basis of the best identity scores with known MBLs, four ORFs were cloned into Escherichia coli for heterologous expression. Among their products, one (blr6230) encoded by the Bradyrhizobium japonicum USDA110 genome, named BJP-1, hydrolyzed β-lactams when expressed in E. coli. BJP-1 enzyme is most closely related to the CAU-1 enzyme from Caulobacter vibrioides (40% amino acid sequence identity), a member of subclass B3 MBLs. A kinetic analysis revealed that BJP-1 efficiently hydrolyzed most β-lactam substrates, except aztreonam, ticarcillin, and temocillin, with the highest catalytic efficiency measured with meropenem. Compared to other MBLs, BJP-1 was less sensitive to inactivation by chelating agents.


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