Cryo-electron microscopy structure of the di-domain core of polyketide synthase 13, essential for mycobacterial mycolic acid synthesis.

Mycobacteria are known for their complex cell wall, which comprises layers of peptidoglycan, polysaccharides and unusual fatty acids known as mycolic acids that form their unique outer membrane. Polyketide synthase 13 (Pks13) of , the bacterial organism causing tuberculosis, catalyses the last step of mycolic acid synthesis prior to export to and assembly in the cell wall. Due to its essentiality, Pks13 is a target for several novel anti-tubercular inhibitors, but its 3D structure and catalytic reaction mechanism remain to be fully elucidated.

Quantitation of glyphosate, glufosinate, and AMPA in drinking water and surface waters using direct injection and charged-surface ultra-high performance liquid chromatography-tandem mass spectrometry.

Herbicides glyphosate (N-(phosphonomethyl)glycine) and glufosinate (2-amino-4-(hydroxymethylphosphinyl)butanoic acid) and the main transformation product of glyphosate, aminomethanephosphonic acid (AMPA), are challenging to analyze for in environmental samples. The quantitative method developed by this study adapts previously standardized dechlorination procedures coupled to a novel charged surface C column, ultra-high performance liquid chromatography-tandem mass spectrometry, polarity switching, and direct injection. The method was applied to chlorinated tap water, as well as river samples, collected in the City of Winnipeg and rural Manitoba, Canada.

Quantitation of Canadian organic ultraviolet filters using polarity switching and ultra-high performance liquid chromatography-tandem mass spectrometry.

Ultraviolet filters (UVFs) absorb UV light and are comprised of numerous classes of compounds including inorganic and organic. They have been used for decades in protecting humans from skin damage and cancer. Recent studies have shown that UVFs are found in many phases of abiotic and biotic systems with their physical-chemical characteristics determining environmental fate and potential biological impacts such as bioaccumulation.

Insitu kinetics of human pharmaceutical conjugates and the impact of transformation, deconjugation, and sorption on persistence in wastewater batch bioreactors.

The fate of selected common pharmaceuticals and four of their major conjugates in wastewater batch bioreactors was evaluated to determine how treatment plant parameters such as addition of air, and the presence of waste activated sludge (WAS) could influence the removal of parent compounds and conjugates. Under a realistic hydraulic residence time (HRT) for each treatment sub-process of approximately 2 h, acetaminophen and its sulfate metabolite were both rapidly degraded (>99%). Propranolol was sulfated and concurrently removed.

Identification of Substituted Amino Acid Hydrazides as Novel Anti-Tubercular Agents, Using a Scaffold Hopping Approach.

Discovery and development of new therapeutic options for the treatment of () infection, particularly drug-resistant strains, are urgently required to tackle the global burden of this disease. Herein, we reported the synthesis of a novel series of N-substituted amino acid hydrazides, utilising a scaffold hopping approach within a library of anti-tubercular agents. Efficacy and selectivity were evaluated against three strains of (wild-type, isoniazid-resistant and rifampicin-resistant), and cytotoxicity against macrophages .

Validated quantitative cannabis profiling for Canadian regulatory compliance - Cannabinoids, aflatoxins, and terpenes.

In response to the Canadian federal government's Cannabis Tracking and Licensing System compliance standards, a quantitative method was created for cannabis analysis, and validated using Eurachem V.2 (2014) guidelines. Cannabinol, cannabidiol, cannabigerol, cannabichromene, cannabidiolic acid, cannabigerolic acid, Δ-9-tetrahydrocannabinol, and Δ-9-tetrahydrocannabinolic acid A were all analysed by scheduled multiple reaction monitoring (MRM) via LC-MS/MS and isotope dilution.

Identification of Novel Benzoxa-[2,1,3]-diazole Substituted Amino Acid Hydrazides as Potential Anti-Tubercular Agents.

Discovery and development of new therapeutic options for the treatment of () infection are desperately needed to tackle the continuing global burden of this disease and the efficacy and cost limitations associated with current medicines. Herein, we report the synthesis of a series of novel benzoxa-[2,1,3]-diazole substituted amino acid hydrazides in a two-step synthesis and evaluate their inhibitory activity against and selected bacterial strains of clinical importance utilising an end point-determined REMA assay. Alongside this, their potential for undesired cytotoxicity against mammalian cells was assessed employing standard MTT assay methodologies.

Crystal structure of Mycobacterium tuberculosis FadB2 implicated in mycobacterial β-oxidation.

The intracellular pathogen Mycobacterium tuberculosis is the causative agent of tuberculosis, which is a leading cause of mortality worldwide. The survival of M. tuberculosis in host macrophages through long-lasting periods of persistence depends, in part, on breaking down host cell lipids as a carbon source.

Distribution and fate of pharmaceuticals and their metabolite conjugates in a municipal wastewater treatment plant.

Some pharmaceutical conjugates can be excreted into wastewaters at levels rivalling those of the parent compounds; however, little is known about this potential reservoir of pharmaceuticals to aquatic systems. We evaluated the occurrence and distribution of four different classes of pharmaceuticals and their metabolite conjugates in a wastewater treatment plant over four months. Aqueous and suspended solids fractions of primary, mixed liquor, secondary, and final effluent, along with return activated sludge, and waste activated sludge were assessed.

Variation in bacterial community structure of aerobic granular and suspended activated sludge in the presence of the antibiotic sulfamethoxazole.

The treatment performance and bacterial community structure of conventional activated sludge and aerobic granules exposed to antibiotic sulfamethoxazole (SMX) was studied. For three months, two sets of sequencing batch reactors inoculated with conventional and granular biomass were fed with a synthetic municipal wastewater containing 2 μg/L SMX. The presence of SMX had no significant impacts on treatment performance of the reactors as well as stability of the granules.

Removal of antibiotic sulfamethoxazole by anoxic/anaerobic/oxic granular and suspended activated sludge processes.

This study investigates the removal of the antibiotic sulfamethoxazole (SMX) in two sets of anoxic/anaerobic/oxic sequencing batch reactors inoculated with either suspended or granular activated sludge. Continuously, for three months, 2 μg/L SMX was spiked into the reactor feeds in a synthetic municipal wastewater with COD, total nitrogen (TN) and total phosphorous (TP) of 400, 43 and 7 mg/L, respectively. The presence of SMX had no significant impact on treatment performance of the suspended and granular biomass.

Measurement of thyroxine and its glucuronide in municipal wastewater and solids using weak anion exchange solid phase extraction and ultrahigh performance liquid chromatography-tandem mass spectrometry.

A solids extraction method, using sonication in combination with weak anion exchange solid phase extraction, was created to extract thyroxine (T4) and thyroxine-O-β-d-glucuronide (T4-Glc) simultaneously from wastewaters and sludges, and to quantify these compounds via reversed-phase ultra-high performance liquid chromatography-tandem mass spectrometry. The method limits of quantification were all in the low ng/g (dry weight solids) range for both T4 and T4-Glc: 2.13 and 2.

Synthesis and SAR evaluation of novel thioridazine derivatives active against drug-resistant tuberculosis.

The neuroleptic drug thioridazine has been recently repositioned as possible anti-tubercular drug. Thioridazine showed anti-tubercular activity against drug resistant mycobacteria but it is endowed with adverse side effects. A small library of thioridazine derivatives has been designed through the replacement of the piperidine and phenothiazine moieties, with the aim to improve the anti-tubercular activity and to reduce the cytotoxic effects.

Simultaneous quantification of propranolol and sulfamethoxazole and major human metabolite conjugates 4-hydroxy-propranolol sulfate and sulfamethoxazole-β-glucuronide in municipal wastewater-A framework for multiple classes of drugs and conjugates.

Recent data suggests there are non-trivial amounts of human pharmaceutical conjugates potentially entering environmental surface waters. These compounds could contribute to eliciting toxic effects on aquatic biota either directly or indirectly, via de-conjugation. The need for developing a single method for quantifying both parents and conjugates is necessary.

Design and Synthesis of 1-((1,5-Bis(4-chlorophenyl)-2-methyl-1H-pyrrol-3-yl)methyl)-4-methylpiperazine (BM212) and N-Adamantan-2-yl-N'-((E)-3,7-dimethylocta-2,6-dienyl)ethane-1,2-diamine (SQ109) Pyrrole Hybrid Derivatives: Discovery of Potent Antitubercular Agents Effective against Multidrug-Resistant Mycobacteria.

Novel pyrroles have been designed, synthesized, and evaluated against mycobacterial strains. The pyrroles have originally been designed as hybrids of the antitubercular drugs BM212 (1) and SQ109 (2), which showed common chemical features with very similar topological distribution. A perfect superposition of the structures of 1 and 2 revealed by computational studies suggested the introduction of bulky substituents at the terminal portion of the pyrrole C3 side chain and the removal of the C5 aryl moiety.

Selective serotonin reuptake inhibitors and β-blocker transformation products may not pose a significant risk of toxicity to aquatic organisms in wastewater effluent-dominated receiving waters.

A probabilistic ecological risk assessment was conducted for the transformation products (TPs) of 3 β-blockers (atenolol, metoprolol, and propranolol) and 5 selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline) to assess potential threats to aquatic organisms in effluent-dominated surface waters. To this end, the pharmacokinetic literature, the University of Minnesota's Biocatalysis/Biodegradation Database Pathway Prediction System aerobic microbial degradation software, and photolysis literature pertaining to β-blockers and SSRIs were used to determine their most likely TPs formed via human metabolism, aerobic biodegradation, and photolysis, respectively. Monitoring data from North American and European surface waters receiving human wastewater inputs were the basis of the exposure characterizations of the parent compounds and the TPs, where available.

VapC20 of Mycobacterium tuberculosis cleaves the sarcin-ricin loop of 23S rRNA.

The highly persistent and often lethal human pathogen, Mycobacterium tuberculosis contains at least 88 toxin-antitoxin genes. More than half of these encode VapC PIN domain endoribonucleases that inhibit cell growth by unknown mechanisms. Here we show that VapC20 of M.

Characterization of a beta-hydroxybutyryl-CoA dehydrogenase from Mycobacterium tuberculosis.

The lipid-rich cell wall of mycobacteria is essential not only for virulence but also for survival. Whilst anabolic pathways for mycobacterial lipid biosynthesis have been well studied, there has been little research looking into lipid catabolism. The genome of Mycobacterium tuberculosis encodes multiple enzymes with putative roles in the beta-oxidation of fatty acids.

Platensimycin activity against mycobacterial beta-ketoacyl-ACP synthases.

Background: There is an urgent need for the discovery and development of new drugs against Mycobacterium tuberculosis, the causative agent of tuberculosis, especially due to the recent emergence of multi-drug and extensively-drug resistant strains. Herein, we have examined the susceptibility of mycobacteria to the natural product platensimycin.

Methods And Findings: We have demonstrated that platensimycin has bacteriostatic activity against the fast growing Mycobacterium smegmatis (MIC = 14 microg/ml) and against Mycobacterium tuberculosis (MIC = 12 microg/ml).

Identification of 2-aminothiazole-4-carboxylate derivatives active against Mycobacterium tuberculosis H37Rv and the beta-ketoacyl-ACP synthase mtFabH.

Background: Tuberculosis (TB) is a disease which kills two million people every year and infects approximately over one-third of the world's population. The difficulty in managing tuberculosis is the prolonged treatment duration, the emergence of drug resistance and co-infection with HIV/AIDS. Tuberculosis control requires new drugs that act at novel drug targets to help combat resistant forms of Mycobacterium tuberculosis and reduce treatment duration.

The Mycobacterium tuberculosis beta-ketoacyl-acyl carrier protein synthase III activity is inhibited by phosphorylation on a single threonine residue.

Mycolic acids are hallmark features of the Mycobacterium tuberculosis cell wall. They are synthesized by the condensation of two fatty acids, a C56-64-meromycolyl chain and a C24-26-fatty acyl chain. Meromycolates are produced via the combination of type I and type II fatty acid synthases (FAS-I and FAS-II).

Loss of a mycobacterial gene encoding a reductase leads to an altered cell wall containing beta-oxo-mycolic acid analogs and accumulation of ketones.

Mycolic acids are essential components of the mycobacterial cell wall. In this study, we show that a gene encoding a reductase involved in the final step of mycolic acid biosynthesis can be deleted in Mycobacterium smegmatis without affecting cell viability. Deletion of MSMEG4722 (ortholog of Mycobacterium tuberculosis Rv2509) altered culture characteristics and antibiotic sensitivity.

Tuberculosis: a balanced diet of lipids and carbohydrates.

In spite of effective antibiotics to treat TB (tuberculosis) since the early 1960s, we enter the new millennium with TB currently the leading cause of death from a single infectious agent, killing more than 3 million people worldwide each year. Thus an understanding of drug-resistance mechanisms, the immunobiology of cell wall components to elucidate host-pathogen interactions and the discovery of new drug targets are now required for the treatment of TB. Above the plasma membrane is a classical chemotype IV peptidoglycan to which is attached the macromolecular structure, mycolyl-arabinogalactan via a unique diglycosylphosphoryl bridge.

Synthesis and biological evaluation of NAS-21 and NAS-91 analogues as potential inhibitors of the mycobacterial FAS-II dehydratase enzyme Rv0636.

The identification of potential new anti-tubercular chemotherapeutics is paramount due to the recent emergence of extensively drug-resistant strains of Mycobacterium tuberculosis (XDR-TB). Libraries of NAS-21 and NAS-91 analogues were synthesized and evaluated for their whole-cell activity against Mycobacterium bovis BCG. NAS-21 analogues 1 and 2 demonstrated enhanced whole-cell activity in comparison to the parental compound, and an M.