Discovering type I cis-AT polyketides through computational mass spectrometry and genome mining with Seq2PKS.

Type 1 polyketides are a major class of natural products used as antiviral, antibiotic, antifungal, antiparasitic, immunosuppressive, and antitumor drugs. Analysis of public microbial genomes leads to the discovery of over sixty thousand type 1 polyketide gene clusters. However, the molecular products of only about a hundred of these clusters are characterized, leaving most metabolites unknown.

An ECD and NMR/DP4+ Computational Pipeline for Structure Revision and Elucidation of Diphenazine-Based Natural Products.

Discovery and structure elucidation of natural products available in infinitesimally small quantities are recognized challenge. This challenge is epitomized by the diphenazine class of molecules that contain three bridged stereocenters, several conformations, ring fusions, and multiple spatially isolated phenols. Because empirical NMR and spatial analyses using ROESY/NOESY were unsuccessful in tackling these challenges, we developed a computational pipeline to determine the relative and absolute configurations and phenol positions of diphenazines as inhibitors of eukaryotic translation initiation factor 4E (eIF4E) protein-protein interactions.

Not all bad: Gyromitrin has a limited distribution in the false morels as determined by a new ultra high-performance liquid chromatography method.

Gyromitrin (acetaldehyde -methyl--formylhydrazone) and its homologs are deadly mycotoxins produced most infamously by the lorchel (also known as false morel) , which is paradoxically consumed as a delicacy in some parts of the world. There is much speculation about the presence of gyromitrin in other species of the lorchel family (Discinaceae), but no studies have broadly assessed its distribution. Given the history of poisonings associated with the consumption of and , we hypothesized that gyromitrin evolved in the last common ancestor of these taxa and would be present in their descendants with adaptive loss of function in the nested truffle clade, .

Discovery of Surfactins as Inhibitors of MicroRNA Processing Using Cat-ELCCA.

MicroRNAs (miRNAs) are a family of small noncoding RNAs that regulate gene expression. Due to their important activity in the fine-tuning of protein translation, abnormal expression of miRNAs has been linked to many human diseases, making the targeting of miRNAs attractive as a novel therapeutic strategy. Accordingly, researchers have been heavily engaged in the discovery of small molecule modulators of miRNAs.

Adipostatins E-J, New Potent Antimicrobials Identified as Inhibitors of Coenzyme-A Biosynthesis.

Phosphopantetheine is a key structural element in biological acyl transfer reactions found embedded within coenzyme A (CoA). Phosphopantothenoylcysteine synthetase (PPCS) is responsible for installing a cysteamine group within phosphopantetheine. Therefore, it holds considerable potential as a drug target for developing new antimicrobials.

Discovery of nicoyamycin A, an inhibitor of uropathogenic Escherichia coli growth in low iron environments.

High-throughput screening and activity-guided purification identified nicoyamycin A, a natural product comprised of an uncommon 3-methyl-1,4-dioxane ring incorporated into a desferrioxamine-like backbone via a spiroaminal linkage. Nicoyamycin A potently inhibits uropathogenic Escherichia coli growth in low iron medium, a promising step toward developing novel antibiotics to treat recalcitrant bacterial infections.

Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C-H Functionalization.

Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total synthesis of the juvenimicin, M-4365, and rosamicin classes of macrolide antibiotics via late-stage diversification. Synthetic chemistry was employed to generate the tylactone hexaketide chain elongation intermediate that was accepted by the juvenimicin (Juv) ketosynthase of the penultimate JuvEIV PKS module.

Discovery of cahuitamycins as biofilm inhibitors derived from a convergent biosynthetic pathway.

Pathogenic microorganisms often have the ability to attach to a surface, building a complex matrix where they colonize to form a biofilm. This cellular superstructure can display increased resistance to antibiotics and cause serious, persistent health problems in humans. Here we describe a high-throughput in vitro screen to identify inhibitors of Acinetobacter baumannii biofilms using a library of natural product extracts derived from marine microbes.

Actinoramide A Identified as a Potent Antimalarial from Titration-Based Screening of Marine Natural Product Extracts.

Methods to identify the bioactive diversity within natural product extracts (NPEs) continue to evolve. NPEs constitute complex mixtures of chemical substances varying in structure, composition, and abundance. NPEs can therefore be challenging to evaluate efficiently with high-throughput screening approaches designed to test pure substances.

Novel Lobophorins Inhibit Oral Cancer Cell Growth and Induce Atf4- and Chop-Dependent Cell Death in Murine Fibroblasts.

As part of the International Cooperative Biodiversity Groups (ICBG) Program, we were interested in identifying biologically active unfolded protein response (UPR) inducing compounds from marine microorganisms isolated from Costa Rican biota. With this aim in mind we have now generated more than 33,000 unique prefractionated natural product extracts from marine and terrestrial organisms that have been submitted to the Center of Chemical Genomics (CCG) at the University of Michigan for high throughput screening (HTS). An effective complementary cell-based assay to identify novel modulators of UPR signaling was used for screening extracts.

Microscale Adaptation of In Vitro Transcription/Translation for High-Throughput Screening of Natural Product Extract Libraries.

Novel antimicrobials that effectively inhibit bacterial growth are essential to fight the growing threat of antibiotic resistance. A promising target is the bacterial ribosome, a 2.5 MDa organelle susceptible to several biorthogonal modes of action used by different classes of antibiotics.

The combined use of alphavirus replicons and pseudoinfectious particles for the discovery of antivirals derived from natural products.

Alphaviruses are a prominent class of reemergent pathogens due to their globally expanding ranges, potential for lethality, and possible use as bioweapons. The absence of effective treatments for alphaviruses highlights the need for innovative strategies to identify antiviral agents. Primary screens that use noninfectious self-replicating RNAs, termed replicons, have been used to identify potential antiviral compounds for alphaviruses.

Identification of protein kinase C activation as a novel mechanism for RGS2 protein upregulation through phenotypic screening of natural product extracts.

Biochemical high-throughput screening is widely used in drug discovery, using a variety of small molecule libraries. However, broader screening strategies may be more beneficial to identify novel biologic mechanisms. In the current study we used a β-galactosidase complementation method to screen a selection of microbial-derived pre-fractionated natural product extracts for those that increase regulator of G protein signaling 2 (RGS2) protein levels.

Baulamycins A and B, broad-spectrum antibiotics identified as inhibitors of siderophore biosynthesis in Staphylococcus aureus and Bacillus anthracis.

Siderophores are high-affinity iron chelators produced by microorganisms and frequently contribute to the virulence of human pathogens. Targeted inhibition of the biosynthesis of siderophores staphyloferrin B of Staphylococcus aureus and petrobactin of Bacillus anthracis hold considerable potential as a single or combined treatment for methicillin-resistant S. aureus (MRSA) and anthrax infection, respectively.

Discovery of potent broad spectrum antivirals derived from marine actinobacteria.

Natural products provide a vast array of chemical structures to explore in the discovery of new medicines. Although secondary metabolites produced by microbes have been developed to treat a variety of diseases, including bacterial and fungal infections, to date there has been limited investigation of natural products with antiviral activity. In this report, we used a phenotypic cell-based replicon assay coupled with an iterative biochemical fractionation process to identify, purify, and characterize antiviral compounds produced by marine microbes.

Sekikaic acid and lobaric acid target a dynamic interface of the coactivator CBP/p300.

Capturing a coactivator, naturally: the natural products sekikaic acid and lobaric acid, isolated after a high-throughput screen of a structurally diverse extract collection, effectively target the dynamic binding interfaces of the GACKIX domain of the coactivator CBP/p300. These molecules are the most effective inhibitors of the GACKIX domain yet described and are uniquely selective for this domain.

Titration-based screening for evaluation of natural product extracts: identification of an aspulvinone family of luciferase inhibitors.

The chemical diversity of nature has tremendous potential for the discovery of molecular probes and medicinal agents. However, sensitivity of HTS assays to interfering components of crude extracts derived from plants, and macro- and microorganisms has curtailed their use in lead discovery. Here, we describe a process for leveraging the concentration-response curves obtained from quantitative HTS to improve the initial selection of "actives" from a library of partially fractionated natural product extracts derived from marine actinomycetes and fungi.

Complementary cell-based high-throughput screens identify novel modulators of the unfolded protein response.

Despite advances toward understanding the prevention and treatment of many cancers, patients who suffer from oral squamous cell carcinoma (OSCC) confront a survival rate that has remained unimproved for more than 2 decades, indicating our ability to treat them pharmacologically has reached a plateau. In an ongoing effort to improve the clinical outlook for this disease, we previously reported that an essential component of the mechanism by which the proteasome inhibitor bortezomib (PS-341, Velcade) induced apoptosis in OSCC required the activation of a terminal unfolded protein response (UPR). Predicated on these studies, the authors hypothesized that high-throughput screening (HTS) of large diverse chemical libraries might identify more potent or selective small-molecule activators of the apoptotic arm of the UPR to control or kill OSCC.

Surgical airway management in Pierre Robin sequence: is there a role for tongue-lip adhesion?

Objective: The purpose of this study was to examine the efficacy of tongue-lip adhesion (TLA) in the management of clinically significant airway obstruction associated with Pierre Robin sequence.

Design: The records of all children admitted to The Children's Hospital of Philadelphia with a diagnosis of Pierre Robin sequence were reviewed. Charts were reviewed for birth data, diagnosis, preoperative airway management methods, and surgical intervention.

Nonemergent hypertension. New perspectives for the emergency medicine physician.

The emergency medicine physician must evaluate and treat hypertensive patients in a variety of contexts, ranging from the compliant patient with well-controlled blood pressure who presents for an unrelated problem, to the patient with asymptomatic blood pressure elevation, to the patient with a true hypertensive urgency or emergency. Recently, the approach to the treatment of adult hypertension has been modified to take into account advances in the understanding of individual patient risk factors and relative risk of cardiovascular complications. Additionally, no data currently exist that show a benefit to acutely lowering the blood pressure of asymptomatic patients with severe blood pressure elevation, but there is data to suggest that it may be harmful, especially in patients with cardiovascular risk factors.