Read by QxMD icon Read

cryptical biosynthesis

Tao Jiang, Menghua Wang, Li Li, Jinguang Si, Bo Song, Cao Zhou, Meng Yu, Xuewei Wang, Yonggang Zhang, Gang Ding, Zhongmei Zou
Overexpression of laeA in Chaetomium globosum CBS148.51 up-regulated expression of the chaetoglobosin gene cluster and resulted in the isolation of a new cytochalasan, chaetoglobosin Z (1), together with six known analogues, chaetoglobosins A (2), B (3), D (4), E (5), O (6), and V (7). RT-PCR analysis confirmed that the key genes in the chaetoglobosin gene cluster were significantly up-regulated. The structure of the new compound chaetoglobosin Z (1) was elucidated using NMR data. The relative and absolute configurations were determined by NOESY and electronic circular dichroism combined with quantum-chemical calculations adopting time-dependent density functional theory methods, respectively...
October 19, 2016: Journal of Natural Products
Yu Nakashima, Yoko Egami, Miki Kimura, Toshiyuki Wakimoto, Ikuro Abe
Sponge metagenomes are a useful platform to mine cryptic biosynthetic gene clusters responsible for production of natural products involved in the sponge-microbe association. Since numerous sponge-derived bioactive metabolites are biosynthesized by the symbiotic bacteria, this strategy may concurrently reveal sponge-symbiont produced compounds. Accordingly, a metagenomic analysis of the Japanese marine sponge Discodermia calyx has resulted in the identification of a hybrid type I polyketide synthase-nonribosomal peptide synthetase gene (kas)...
2016: PloS One
Marta Maciejewska, Delphine Adam, Loïc Martinet, Aymeric Naômé, Magdalena Całusińska, Philippe Delfosse, Monique Carnol, Hazel A Barton, Marie-Pierre Hayette, Nicolas Smargiasso, Edwin De Pauw, Marc Hanikenne, Denis Baurain, Sébastien Rigali
Moonmilk speleothems of limestone caves host a rich microbiome, among which Actinobacteria represent one of the most abundant phyla. Ancient medical texts reported that moonmilk had therapeutical properties, thereby suggesting that its filamentous endemic actinobacterial population might be a source of natural products useful in human treatment. In this work, a screening approach was undertaken in order to isolate cultivable Actinobacteria from moonmilk of the Grotte des Collemboles in Belgium, to evaluate their taxonomic profile, and to assess their potential in biosynthesis of antimicrobials...
2016: Frontiers in Microbiology
Jyotsna L Pandey, Sarah N Kiemle, Tom L Richard, Yimin Zhu, Daniel J Cosgrove, Charles T Anderson
Lignin is a key structural component of plant cell walls that provides rigidity, strength, and resistance against microbial attacks. This hydrophobic polymer also serves a crucial role in water transport. Despite its abundance and essential functions, several aspects of lignin biosynthesis and deposition remain cryptic. Lignin precursors are known to be synthesized in the cytoplasm by complex biosynthetic pathways, after which they are transported to the apoplastic space, where they are polymerized via free radical coupling reactions into polymeric lignin...
2016: Frontiers in Plant Science
Olga N Sekurova, Ignacio Pérez-Victoria, Jesús Martín, Kristin F Degnes, Håvard Sletta, Fernando Reyes, Sergey B Zotchev
Activation of silent biosynthetic gene clusters in Streptomyces bacteria via overexpression of cluster-specific regulatory genes is a promising strategy for the discovery of novel bioactive secondary metabolites. This approach was used in an attempt to activate a cryptic gene cluster in a marine sponge-derived Streptomyces albus PVA94-07 presumably governing the biosynthesis of peptide-based secondary metabolites. While no new peptide-based metabolites were detected in the recombinant strain, it was shown to produce at least four new analogues of deferoxamine with additional acyl and sugar moieties, for which chemical structures were fully elucidated...
2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Benson Lim, Nicholas Smirnoff, Christopher S Cobbett, John F Golz
In higher plants the L-galactose pathway represents the major route for ascorbate biosynthesis. The first committed step of this pathway is catalyzed by the enzyme GDP-L-galactose phosphorylase and is encoded by two paralogs in Arabidopsis - VITAMIN C2 (VTC2) and VTC5. The first mutant of this enzyme, vtc2-1, isolated via an EMS mutagenesis screen, has approximately 20-30% of wildtype ascorbate levels and has been reported to have decreased growth under standard laboratory conditions. Here, we show that a T-DNA insertion into the VTC2 causes a similar reduction in ascorbate levels, but does not greatly affect plant growth...
2016: Frontiers in Plant Science
Lena Studt, Sarah M Rösler, Immo Burkhardt, Birgit Arndt, Michael Freitag, Hans-Ulrich Humpf, Jeroen S Dickschat, Bettina Tudzynski
Filamentous fungi produce a vast array of secondary metabolites (SMs) and some play a role in agriculture or pharmacology. Sequencing of the rice pathogen Fusarium fujikuroi revealed the presence of far more SM-encoding genes than known products. SM production is energy-consuming and thus tightly regulated, leaving the majority of SM gene clusters silent under laboratory conditions. One important regulatory layer in SM biosynthesis involves histone modifications that render the underlying genes either silent or poised for transcription...
June 27, 2016: Environmental Microbiology
Danyao Du, Yohei Katsuyama, Hiroyasu Onaka, Manabu Fujie, Noriyuki Satoh, Kazuo Shin-Ya, Yasuo Ohnishi
Streptomyces sp. MSC090213JE08 seems to have more than 20 cryptic biosynthetic gene clusters for secondary metabolites. We aimed to activate some of them by forced production of Streptomyces antibiotic regulatory protein (SARP) family transcriptional activators. We constructed seven recombinant strains, each of which contained a SARP gene under the control of a constitutive promoter, and subjected them to comparative metabolic profiling analysis. Four of the seven strains produced nine metabolites that were hardly detected in the control strains...
August 3, 2016: Chembiochem: a European Journal of Chemical Biology
Peter Mantle, Marina Venturini Copetti, Alan Buddie, Jens Frisvad
The unusual attribution of trace amounts of ochratoxin A in some Chinese food commodities to Penicillium polonicum is questioned by European experience in searches for ochratoxinogenic food-spoilage Penicillia, where mistaken attribution is now known to have been due to cryptic Penicillium verrucosum contamination. Consequently, selection of single-spore isolates is recommended as pre-requisite for attributing mycotoxin biosynthetic potential to fungi.
2016: Toxins
Yuan Sun, Christine Gadoury, Matthew P Hirakawa, Richard J Bennett, Doreen Harcus, Anne Marcil, Malcolm Whiteway
UNLABELLED: It has been proposed that the ancestral fungus was mating competent and homothallic. However, many mating-competent fungi were initially classified as asexual because their mating capacity was hidden behind layers of regulation. For efficient in vitro mating, the essentially obligate diploid ascomycete pathogen Candida albicans has to change its mating type locus from heterozygous MTLa/α to homozygous MTLa/a or MTLα/α and then undergo an environmentally controlled epigenetic switch to the mating-competent opaque form...
2016: MBio
Koji Narita, Ryota Chiba, Atsushi Minami, Motoichiro Kodama, Isao Fujii, Katsuya Gomi, Hideaki Oikawa
Heterologous expression of four candidate genes found in ophiobolin gene clusters from three fungal strains was employed to elucidate the late-stage biosynthetic pathway of phytotoxin ophiobolin. Expression of oblBAc (cytochrome P450) from the cryptic gene cluster gave unexpected products, and that of oblBBm/oblBEv from the gene cluster of ophiobolin producers, with oblDBm as the transporter, yielded intermediate ophiobolin C through an unusual four-step oxidation process. The observation made in this study may provide a useful guideline for the elucidation of genuine biosynthetic pathways of natural products...
May 6, 2016: Organic Letters
Lingxin Kong, Weike Zhang, Yit Heng Chooi, Lu Wang, Bo Cao, Zixin Deng, Yiwen Chu, Delin You
Xantholipin and several related polycyclic xanthone antibiotics feature a unique xanthone ring nucleus within a highly oxygenated, angular, fused hexacyclic system. In this study, we demonstrated that a flavin-dependent monooxygenase (FMO) XanO4 catalyzes the oxidative transformation of an anthraquinone to a xanthone system during the biosynthesis of xantholipin. In vitro isotopic labeling experiments showed that the reaction involves sequential insertion of two oxygen atoms, accompanied by an unexpected cryptic demethoxylation reaction...
April 21, 2016: Cell Chemical Biology
Katherine Williams, Agnieszka J Szwalbe, Nicholas P Mulholland, Jason L Vincent, Andrew M Bailey, Christine L Willis, Thomas J Simpson, Russell J Cox
Fungal maleidrides are an important family of bioactive secondary metabolites that consist of 7, 8, or 9-membered carbocycles with one or two fused maleic anhydride moieties. The biosynthesis of byssochlamic acid (a nonadride) and agnestadride A (a heptadride) was investigated through gene disruption and heterologous expression experiments. The results reveal that the precursors for cyclization are formed by an iterative highly reducing fungal polyketide synthase supported by a hydrolase, together with two citrate-processing enzymes...
June 1, 2016: Angewandte Chemie
Matthew L Dennis, Noel P Pitcher, Michael D Lee, Aaron J DeBono, Zhong-Chang Wang, Jitendra R Harjani, Raphaël Rahmani, Ben Cleary, Thomas S Peat, Jonathan B Baell, James D Swarbrick
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a member of the folate biosynthesis pathway found in prokaryotes and lower eukaryotes that catalyzes the pyrophosphoryl transfer from the ATP cofactor to a 6-hydroxymethyl-7,8-dihydropterin substrate. We report the chemical synthesis of a series of S-functionalized 8-mercaptoguanine (8MG) analogues as substrate site inhibitors of HPPK and quantify binding against the E. coli and S. aureus enzymes (EcHPPK and SaHPPK). The results demonstrate that analogues incorporating acetophenone-based substituents have comparable affinities for both enzymes...
June 9, 2016: Journal of Medicinal Chemistry
Paula C Alves, Diego O Hartmann, Oscar Núñez, Isabel Martins, Teresa L Gomes, Helga Garcia, Maria Teresa Galceran, Richard Hampson, Jörg D Becker, Cristina Silva Pereira
BACKGROUND: The inherent potential of filamentous fungi, especially of Ascomycota, for producing diverse bioactive metabolites remains largely silent under standard laboratory culture conditions. Innumerable strategies have been described to trigger their production, one of the simplest being manipulation of the growth media composition. Supplementing media with ionic liquids surprisingly enhanced the diversity of extracellular metabolites generated by penicillia. This finding led us to evaluate the impact of ionic liquids' stimuli on the fungal metabolism in Aspergillus nidulans and how it reflects on the biosynthesis of secondary metabolites (SMs)...
2016: BMC Genomics
Jian-Ying Wang, Yan-Li Liang, Mei-Rong Hai, Jun-Wen Chen, Zheng-Jie Gao, Qian-Qian Hu, Guang-Hui Zhang, Sheng-Chao Yang
BACKGROUND: Dipsacus asperoides is a traditional Chinese medicinal crop. The root is generally used as a medicine and is frequently prescribed by Chinese doctors for the treatment of back pain, limb paralysis, flutter trauma, tendon injuries, and fractures. With the rapid development of bioinformatics, research has been focused on this species at the gene or molecular level. For purpose of fleshing out genome information about D. asperoides, in this paper we conducted transcriptome analysis of this species...
2016: Frontiers in Plant Science
Patrick Caffrey, Eimear De Poire, James Sheehan, Paul Sweeney
The polyene macrolide group includes important antifungal drugs, to which resistance does not arise readily. Chemical and biological methods have been used in attempts to make polyene antibiotics with fewer toxic side effects. Genome sequencing of producer organisms is contributing to this endeavour, by providing access to new compounds and by enabling yield improvement for polyene analogues obtained by engineered biosynthesis. This recent work is also enhancing bioinformatic methods for deducing the structures of cryptic natural products from their biosynthetic enzymes...
May 2016: Applied Microbiology and Biotechnology
Li Liao, Ruiqin Chen, Ming Jiang, Xiaoqing Tian, Huan Liu, Yong Yu, Chenqi Fan, Bo Chen
BACKGROUND: Halometabolites, an important group of natural products, generally require halogenases for their biosynthesis. Actinomycetes from the Arctic Ocean have rarely been investigated for halogenases and their gene clusters associated, albeit great potential of halometabolite production has been predicted. Therefore, we initiated this research on the screening of halogenases from Arctic marine actinomycetes isolates to explore their genetic potential of halometabolite biosynthesis...
2016: BMC Microbiology
Zheng Zhang, Li Zhang, Jie Zhang, Hongchu Ma, Shutao Sun, Jin Zhong
OBJECTIVE: To obtain the cryptic lanthipeptide from Streptomyces clavuligerus by semi-in vitro biosynthesis that is a novel method for mining lanthipeptides resource from Streptomyces. METHODS: The core peptide of cryptic lanthipeptide was modified in E. coli by nisin modification system, and purified by affinity chromatography and High Performance Liquid Chromatography (HPLC). After the leader peptide was removed, the core peptide was obtained and its dehydration and cyclic structure were analyzed by MALDI-TOF MS and tandem MS...
November 4, 2015: Wei Sheng Wu Xue Bao, Acta Microbiologica Sinica
Wei Li Thong, Kazuo Shin-ya, Makoto Nishiyama, Tomohisa Kuzuyama
Conventional screening for novel bioactive compounds in actinomycetes often results in the rediscovery of known compounds. In contrast, recent genome sequencing revealed that most of the predicted gene clusters for secondary metabolisms are not expressed under standard cultivation conditions. To explore the potential metabolites produced by these gene clusters, we implemented a cryptic gene activation strategy by screening mutants that acquire resistance to rifampicin. The induction of rifampicin resistance in 11 actinomycete strains generated 164 rifampicin-resistant mutants (rif mutants)...
April 22, 2016: Journal of Natural Products
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"