The catechol moiety of obafluorin is essential for antibacterial activity.

Obafluorin is a antibacterial natural product that inhibits threonyl-tRNA synthetase (ThrRS). It acts as a broad-spectrum antibiotic against a range of clinically relevant pathogens and comprises a strained β-lactone ring decorated with catechol and 4-nitro-benzyl moieties. The catechol moiety is widespread in nature and its role in the coordination of ferric iron has been well-characterised in siderophores and Trojan horse antibiotics.

Heterologous Expression of the Formicamycin Biosynthetic Gene Cluster Unveils Glycosylated Fasamycin Congeners.

Formicamycins and their biosynthetic intermediates the fasamycins are polyketide antibiotics produced by KY5 from a pathway encoded by the biosynthetic gene cluster. In this work the ability of M1146 and the ability of Δ to heterologously express the biosynthetic gene cluster were assessed. This led to the identification of eight new glycosylated fasamycins modified at different phenolic groups with either a monosaccharide (glucose, galactose, or glucuronic acid) or a disaccharide comprised of a proximal hexose (either glucose or galactose), with a terminal pentose (arabinose) moiety.

Assessing the Toxicity and Mitigating the Impact of Harmful Blooms in Eutrophic Waters of the Norfolk Broads.

is a toxin-producing microalga, which causes harmful algal blooms globally, frequently leading to massive fish kills that have adverse ecological and economic implications for natural waterways and aquaculture alike. The dramatic effects observed on fish are thought to be due to algal polyether toxins, known as the prymnesins, but their lack of environmental detection has resulted in an uncertainty about the true ichthyotoxic agents. Using qPCR, we found elevated levels of and its lytic virus, PpDNAV-BW1, in a fish-killing bloom on the Norfolk Broads, United Kingdom, in March 2015.

Discovery and characterisation of an amidine-containing ribosomally-synthesised peptide that is widely distributed in nature.

Ribosomally synthesised and post-translationally modified peptides (RiPPs) are a structurally diverse class of natural product with a wide range of bioactivities. Genome mining for RiPP biosynthetic gene clusters (BGCs) is often hampered by poor annotation of the short precursor peptides that are ultimately modified into the final molecule. Here, we utilise a previously described genome mining tool, RiPPER, to identify novel RiPP precursor peptides near YcaO-domain proteins, enzymes that catalyse various RiPP post-translational modifications including heterocyclisation and thioamidation.

Correction: CuAAC click chemistry for the enhanced detection of novel alkyne-based natural product toxins.

Correction for 'CuAAC click chemistry for the enhanced detection of novel alkyne-based natural product toxins' by Edward S. Hems et al., Chem.

CuAAC click chemistry for the enhanced detection of novel alkyne-based natural product toxins.

In the context of discovering and quantifying terminal alkyne-based natural products, here we report the combination of CuAAC click chemistry with LC-MS for the detection of polyether toxins (prymnesins) associated with harmful algal blooms. The added-value of the CuAAC-based approach is evident from our ability to detect novel prymnesin-like compounds in algal species with previously uncharacterised toxins.

Synthesis of glyceryl glycosides related to A-type prymnesin toxins.

A suite of glycosylated glycerol derivatives representing various fragments of the glycosylated ichthyotoxins called prymnesins were chemically synthesised. Glycerol was used to represent a small fragment of the prymnesin backbone, and was glycosylated at the 2° position with the sugars currently reported to be present on prymnesin toxins. Neighbouring group participation was utilised to synthesise 1,2-trans-glycosides.

Insights into toxic blooms: the role of sugars and algal viruses.

is a toxin-producing microalga that causes harmful algal blooms globally, which often result in large-scale fish kills that have severe ecological and economic implications. Although many toxins have previously been isolated from , ambiguity still surrounds the responsible ichthyotoxins in blooms and the biotic and abiotic factors that promote bloom toxicity. A major fish kill attributed to occurred in Spring 2015 on the Norfolk Broads, a low-lying set of channels and lakes (Broads) found on the East of England.

Profiling of Sugar Nucleotides.

Sugar nucleotides are essential building blocks for the glycobiology of all living organisms. Detailed information on the types of sugar nucleotides present in a particular cell and how they change as a function of metabolic, developmental, or disease status is vital. The extraction, identification, and quantification of sugar nucleotides in a given sample present formidable challenges.

A retrospective study to assess patient satisfaction with implant-stabilized prostheses.

Unlabelled: This study measured the levels of patient satisfaction in those who received treatment with implant-retained overdentures, and compared their status before and after therapy. Satisfaction questionnaires were mailed to patients who had previously worn a removable prosthesis. Questions addressed eating, aesthetics and comfort before and after the treatment.

Effect of screw hole filling on retention of implant crowns.

The screw access channels of 15 degrees angled Esthetic Abutments (Brånemark System) were either (a) completely filled with a vinyl polysiloxane impression material (Memosil), (b) partially filled with Memosil or (c) had lower portion filled with Memosil and the remainder with composite resin. The force required to remove a temporarily cemented restoration was measured. The removal force was significantly reduced with the channel completely filled with Memosil compared to those partially filled with Memosil (p<0.