| a practical synthesis of long-chain iso-fatty acids (iso-c12-c19) and related natural products. | a gram-scale synthesis of terminally-branched iso-fatty acids (iso-c12-c19) was developed commencing with methyl undec-10-enoate (methyl undecylenate) (for iso-c12-c14) or the c15 and c16 lactones pentadecanolide (for iso-c15-c17) and hexadecanolide (for iso-c18-c19). central to the approaches outlined is the two-step construction of the terminal isopropyl group through addition of methylmagnesium bromide to the ester/lactones and selective reduction of the resulting tertiary alcohols. thus, the ... | 2013 | 24062846 |
| synthesis and biological activities of the respiratory chain inhibitor aurachin d and new ring versus chain analogues. | aurachins are myxobacterial 3-farnesyl-4(1h)-quinolone derived compounds initially described as respiratory chain inhibitors, more specifically as inhibitors of various cytochrome complexes. they are also known as potent antibiotic compounds. we describe herein the first synthesis of aurachin d through a key conrad-limpach reaction. the same strategy was used to reach some ring as opposed to chain analogues, allowing for the description of structure-activity relationships. biological screening o ... | 2013 | 23946854 |
| set-domain bacterial effectors target heterochromatin protein 1 to activate host rdna transcription. | transcription of rrna genes (rdnas) in the nucleolus is regulated by epigenetic chromatin modifications including histone h3 lysine (de)methylation. here we show that legas4, a legionella pneumophila type iv secretion system (tfss) effector, is targeted to specific rdna chromatin regions in the host nucleolus. legas4 promotes rdna transcription, through its set-domain (named after drosophila su(var)3-9, enhancer of zeste [e(z)], and trithorax [trx]) histone lysine methyltransferase (hkmtase) act ... | 2013 | 23797873 |
| high-titer heterologous production in e. coli of lyngbyatoxin, a protein kinase c activator from an uncultured marine cyanobacterium. | many chemically complex cyanobacterial polyketides and nonribosomal peptides are of great pharmaceutical interest, but the levels required for exploitation are difficult to achieve from native sources. here we develop a framework for the expression of these multifunctional cyanobacterial assembly lines in escherichia coli using the lyngbyatoxin biosynthetic pathway, derived from a marine microbial assemblage dominated by the cyanobacterium moorea producens. heterologous expression of this pathwa ... | 2013 | 23751865 |
| separate origins of ice-binding proteins in antarctic chlamydomonas species. | the green alga chlamydomonas raudensis is an important primary producer in a number of ice-covered lakes and ponds in antarctica. a c. raudensis isolate (uwo241) from lake bonney in the mcmurdo dry valleys, like many other antarctic algae, was found to secrete ice-binding proteins (ibps), which appear to be essential for survival in icy environments. the ibps of several antarctic algae (diatoms, a prymesiophyte, and a prasinophyte) are similar to each other (here designated as type i ibps) and h ... | 2013 | 23536869 |
| identification of a cyclosporine-specific p450 hydroxylase gene through targeted cytochrome p450 complement (cypome) disruption in sebekia benihana. | it was previously proposed that regio-specific hydroxylation of an immunosuppressive cyclosporine (csa) at the 4th n-methyl leucine is mediated by cytochrome p450 hydroxylase (cyp) in the rare actinomycete sebekia benihana. this modification is thought to be the reason for the hair growth-promoting side effect without the immunosuppressive activity of csa. through s. benihana genome sequencing and in silico analysis, we identified the complete cytochrome p450 complement (cypome) of s. benihana, ... | 2013 | 23354713 |
| a laterally acquired galactose oxidase-like gene is required for aerial development during osmotic stress in streptomyces coelicolor. | phylogenetic reconstruction revealed that most actinobacterial orthologs of s. coelicolor sco2837, encoding a metal-dependent galactose oxidase-like protein, are found within streptomyces and were probably acquired by horizontal gene transfer from fungi. disruption of sco2837 (glxa) caused a conditional bld phenotype that could not be reversed by extracellular complementation. studies aimed at characterising the regulation of expression of glxa showed that it is not a target for other bld genes. ... | 2013 | 23326581 |
| a proteomic approach provides new insights into the control of soil-borne plant pathogens by bacillus species. | beneficial microorganisms (also known as biopesticides) are considered to be one of the most promising methods for more rational and safe crop management practices. we used bacillus strains eu07, qst713 and fzb24, and investigated their inhibitory effect on fusarium. bacterial cell cultures, cell-free supernatants and volatiles displayed varying degrees of suppressive effect. proteomic analysis of secreted proteins from eu07 and fzb24 revealed the presence of lytic enzymes, cellulases, proteases ... | 2013 | 23301041 |
| a highly stable d-amino acid oxidase of the thermophilic bacterium rubrobacter xylanophilus. | d-amino acid oxidase (dao) is a biotechnologically attractive enzyme that can be used in a variety of applications, but its utility is limited by its relatively poor stability. a search of a bacterial genome database revealed a gene encoding a protein homologous to dao in the thermophilic bacterium rubrobacter xylanophilus (rxdao). the recombinant protein expressed in escherichia coli was a monomeric protein containing noncovalently bound flavin adenine dinucleotide as a cofactor. this protein e ... | 2014 | 25217016 |
| car: contig assembly of prokaryotic draft genomes using rearrangements. | next generation sequencing technology has allowed efficient production of draft genomes for many organisms of interest. however, most draft genomes are just collections of independent contigs, whose relative positions and orientations along the genome being sequenced are unknown. although several tools have been developed to order and orient the contigs of draft genomes, more accurate tools are still needed. | 2014 | 25431302 |
| a type iv translocated legionella cysteine phytase counteracts intracellular growth restriction by phytate. | the causative agent of legionnaires' pneumonia, legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. in these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. l. pneumophila replicates in protozoa and mammalian phagocytes within a unique "legionella-containing vacuole." the bacteria govern host cell interactions through the icm/dot type iv secretion system (t4s ... | 2014 | 25339170 |
| complete genome sequence of producer of the glycopeptide antibiotic aculeximycin kutzneria albida dsm 43870t, a representative of minor genus of pseudonocardiaceae. | kutzneria is a representative of a rarely observed genus of the family pseudonocardiaceae. kutzneria species were initially placed in the streptosporangiaceae genus and later reconsidered to be an independent genus of the pseudonocardiaceae. kutzneria albida is one of the eight known members of the genus. this strain is a unique producer of the glycosylated polyole macrolide aculeximycin which is active against both bacteria and fungi. kutzneria albida genome sequencing and analysis allow a deep ... | 2014 | 25301375 |
| mining the metabiome: identifying novel natural products from microbial communities. | microbial-derived natural products provide the foundation for most of the chemotherapeutic arsenal available to contemporary medicine. in the face of a dwindling pipeline of new lead structures identified by traditional culturing techniques and an increasing need for new therapeutics, surveys of microbial biosynthetic diversity across environmental metabiomes have revealed enormous reservoirs of as yet untapped natural products chemistry. in this review, we touch on the historical context of mic ... | 2014 | 25237864 |
| structural and biochemical analysis of a unique phosphatase from bdellovibrio bacteriovorus reveals its structural and functional relationship with the protein tyrosine phosphatase class of phytase. | bdellovibrio bacteriovorus is an unusual δ-proteobacterium that invades and preys on other gram-negative bacteria and is of potential interest as a whole cell therapeutic against pathogens of man, animals and crops. ptps (protein tyrosine phosphatases) are an important class of enzyme involved in desphosphorylating a variety of substrates, often with implications in cell signaling. the b. bacteriovorus open reading frame bd1204 is predicted to encode a ptp of unknown function. bd1204 is both str ... | 2014 | 24718691 |
| discovering new bioactive molecules from microbial sources. | there is an increased need for new drug leads to treat diseases in humans, animals and plants. a dramatic example is represented by the need for novel and more effective antibiotics to combat multidrug-resistant microbial pathogens. natural products represent a major source of approved drugs and still play an important role in supplying chemical diversity, despite a decreased interest by large pharmaceutical companies. novel approaches must be implemented to decrease the chances of rediscovering ... | 2014 | 24661414 |
| role of the bicarbonate-responsive soluble adenylyl cyclase in ph sensing and metabolic regulation. | the evolutionarily conserved soluble adenylyl cyclase (sac, adcy10) was recently identified as a unique source of camp in the cytoplasm and the nucleus. its activity is regulated by bicarbonate and fine-tuned by calcium. as such, and in conjunction with carbonic anhydrase (ca), sac constitutes an hco(-) 3/co(-) 2/ph sensor. in both alpha-intercalated cells of the collecting duct and the clear cells of the epididymis, sac is expressed at significant level and involved in ph homeostasis via apical ... | 2014 | 24575049 |
| improved seamless mutagenesis by recombineering using ccdb for counterselection. | recombineering, which is the use of homologous recombination for dna engineering in escherichia coli, usually uses antibiotic selection to identify the intended recombinant. when combined in a second step with counterselection using a small molecule toxin, seamless products can be obtained. here, we report the advantages of a genetic strategy using ccdb as the counterselectable agent. expression of ccdb is toxic to e. coli in the absence of the ccda antidote so counterselection is initiated by t ... | 2014 | 24369425 |
| improved seamless mutagenesis by recombineering using ccdb for counterselection. | recombineering, which is the use of homologous recombination for dna engineering in escherichia coli, usually uses antibiotic selection to identify the intended recombinant. when combined in a second step with counterselection using a small molecule toxin, seamless products can be obtained. here, we report the advantages of a genetic strategy using ccdb as the counterselectable agent. expression of ccdb is toxic to e. coli in the absence of the ccda antidote so counterselection is initiated by t ... | 2014 | 24369425 |
| iterative polyketide biosynthesis by modular polyketide synthases in bacteria. | modular polyketide synthases (type i pkss) in bacteria are responsible for synthesizing a significant percentage of bioactive natural products. this group of synthases has a characteristic modular organization, and each module within a pks carries out one cycle of polyketide chain elongation; thus each module is non-iterative in function. it was possible to predict the basic structure of a polyketide product from the module organization of the pkss, since there generally existed a co-linearity b ... | 2015 | 26549236 |
| iterative polyketide biosynthesis by modular polyketide synthases in bacteria. | modular polyketide synthases (type i pkss) in bacteria are responsible for synthesizing a significant percentage of bioactive natural products. this group of synthases has a characteristic modular organization, and each module within a pks carries out one cycle of polyketide chain elongation; thus each module is non-iterative in function. it was possible to predict the basic structure of a polyketide product from the module organization of the pkss, since there generally existed a co-linearity b ... | 2015 | 26549236 |
| bacterial genome mining of enzymatic tools for alkyne biosynthesis. | the alkyne is an important functionality widely used in material science, pharmaceutical science, and chemical biology, but the importance of this functionality is contrasted by the very limited number of enzymes known to be involved in alkyne biosynthesis. we recently reported the first known carrier protein-dependent pathway for terminal alkyne formation, and in silico analysis suggested that this mechanism could be widespread in bacteria. in this paper, we screened additional homologous gene ... | 2015 | 26441143 |
| microbial consortium associated with the antarctic marine ciliate euplotes focardii: an investigation from genomic sequences. | we report the characterization of the bacterial consortium associated to euplotes focardii, a strictly psychrophilic marine ciliate that was maintained in laboratory cultures at 4 °c after its first isolation from terra nova bay, in antarctica. by illumina genome analyser, we obtained 11,179 contigs of potential prokaryotic origin and classified them according to the ncbi's prokaryotic attributes table. the majority of these sequences correspond to either bacteroidetes (16 %) or proteobacteria ( ... | 2015 | 25704316 |
| indole is an essential herbivore-induced volatile priming signal in maize. | herbivore-induced volatile organic compounds prime non-attacked plant tissues to respond more strongly to subsequent attacks. however, the key volatiles that trigger this primed state remain largely unidentified. in maize, the release of the aromatic compound indole is herbivore-specific and occurs earlier than other induced responses. we therefore hypothesized that indole may be involved in airborne priming. using indole-deficient mutants and synthetic indole dispensers, we show that herbivore- ... | 2015 | 25683900 |
| first genomic insights into members of a candidate bacterial phylum responsible for wastewater bulking. | filamentous cells belonging to the candidate bacterial phylum ksb3 were previously identified as the causative agent of fatal filament overgrowth (bulking) in a high-rate industrial anaerobic wastewater treatment bioreactor. here, we obtained near complete genomes from two ksb3 populations in the bioreactor, including the dominant bulking filament, using differential coverage binning of metagenomic data. fluorescence in situ hybridization with 16s rrna-targeted probes specific for the two popula ... | 2015 | 25650158 |
| evidence for an iterative module in chain elongation on the azalomycin polyketide synthase. | the assembly-line synthases that produce bacterial polyketide natural products follow a modular paradigm in which each round of chain extension is catalysed by a different set or module of enzymes. examples of deviation from this paradigm, in which a module catalyses either multiple extensions or none are of interest from both a mechanistic and an evolutionary viewpoint. we present evidence that in the biosynthesis of the 36-membered macrocyclic aminopolyol lactones (marginolactones) azalomycin ... | 2016 | 27829923 |
| understanding the structure and function of bacterial expansins: a prerequisite towards practical applications for the bioenergy and agricultural industries. | since the publication of a landmark article on the structure of exlx1 from bacillus subtilis in 2011, our knowledge of bacterial expansins has steadily increased and our view and understanding of these enigmatic proteins has advanced with relation to their structure, phylogenetic relationships and substrate interaction, although the molecular basis for their mechanism of action remains to be determined. lignocellulosic material represents a source of fermentable sugars for the production of biof ... | 2016 | 27365165 |
| identification of the sfp-type pptase eppa from the lichenized fungus evernia prunastri. | in the last decades, natural products from lichens have gained more interest for pharmaceutical application due to the broad range of their biological activity. however, isolation of the compounds of interest directly from the lichen is neither feasible nor sustainable due to slow growth of many lichens. in order to develop a pipeline for heterologous expression of lichen biosynthesis gene clusters and thus the sustainable production of their bioactive compounds we have identified and characteri ... | 2016 | 26784935 |
| structural and functional insights from the metagenome of an acidic hot spring microbial planktonic community in the colombian andes. | a taxonomic and annotated functional description of microbial life was deduced from 53 mb of metagenomic sequence retrieved from a planktonic fraction of the neotropical high andean (3,973 meters above sea level) acidic hot spring el coquito (ec). a classification of unassembled metagenomic reads using different databases showed a high proportion of gammaproteobacteria and alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16s rrna gene fragments we observed th ... | 2012 | 23251687 |
| acyl-coa-binding and self-associating properties of a recombinant 13.3 kda n-terminal fragment of diacylglycerol acyltransferase-1 from oilseed rape. | diacylglycerol acyltransferase (dgat, ec 2.3.1.20) catalyzes the acyl-coa-dependent acylation of sn-1, 2-diacylglycerol to generate triacylglycerol and coa. the deduced amino acid sequence of cdnas encoding dgat1 from plants and mammals exhibit a hydrophilic n-terminal region followed by a number of potential membrane-spanning segments, which is consistent with the membrane-bound nature of this enzyme family. in order to gain insight into the structure/function properties of dgat1 from brassica ... | 2006 | 17192193 |
| fast photochemistry of prototypical phytochromes-a species vs. subunit specific comparison. | phytochromes are multi-domain red light photosensor proteins, which convert red light photons to biological activity utilizing the multitude of structural and chemical reactions. the steady increase in structural information obtained from various bacteriophytochromes has increased understanding about the functional mechanism of the photochemical processes of the phytochromes. furthermore, a number of spectroscopic studies have revealed kinetic information about the light-induced reactions. the s ... | 2015 | 26779488 |
| establishing a reference array for the cs-αβ superfamily of defensive peptides. | "invertebrate defensins" belong to the cysteine-stabilized alpha-beta (cs-αβ), also known as the scorpion toxin-like, superfamily. some other peptides belonging to this superfamily of defensive peptides are indistinguishable from "defensins," but have been assigned other names, making it unclear what, if any, criteria must be met to qualify as an "invertebrate defensin." in addition, there are other groups of defensins in invertebrates and vertebrates that are considered to be evolutionarily unr ... | 2016 | 27863510 |