Publications by authors named "Buijs N"

Neglected anterior glenohumeral dislocations provide a challenging problem for physicians. For many patients with these injuries, reverse shoulder arthroplasty has been the treatment of choice, although the preservation of the patient's own humeral head might have significant advantages. We present a case of a 66-year-old male with a neglected anterior glenohumeral dislocation that he sustained 6 weeks prior when he was hit by a car as a pedestrian.

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Bacitracin is a macrocyclic peptide antibiotic that is widely used as a topical treatment for infections caused by gram-positive bacteria. Mechanistically, bacitracin targets bacteria by specifically binding to the phospholipid undecaprenyl pyrophosphate (CPP), which plays a key role in the bacterial lipid II cycle. Recent crystallographic studies have shown that when bound to CPP, bacitracin adopts a highly ordered amphipathic conformation.

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The prevalence of multidrug-resistant (MDR) pathogens combined with a decline in antibiotic discovery presents a major challenge for health care. To refill the discovery pipeline, we need to find new ways to uncover new chemical entities. Here, we report the global genome mining-guided discovery of new lipopeptide antibiotics tridecaptin A and tridecaptin D, which exhibit unusual bioactivities within their class.

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Background: About 20% of proximal humerus fractures (PHFs) are unstable and/or markedly displaced and therefore require surgery. Locking plate fixation after anatomical reduction has become the current treatment of choice for these fractures in the active population. However, studies have shown complication rates up to 36%, such as loss of reduction and avascular necrosis.

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Since Fleming's discovery of penicillin nearly a century ago, a bounty of natural product antibiotics have been discovered, many of which continue to be of clinical importance today. The structural diversity encountered among nature's repertoire of antibiotics is mirrored by the varying mechanisms of action by which they selectively target and kill bacterial cells. The ability for bacteria to construct and maintain a strong cell wall is essential for their robust growth and survival under a range of conditions.

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Vaccines are a promising therapeutic alternative to monoclonal antibodies against HER-2+ breast cancer. We present the preclinical activity of an ES2B-C001, a VLP-based vaccine being developed for human breast cancer therapy. FVB mice challenged with HER-2+ mammary carcinoma cells QD developed progressive tumors, whereas all mice vaccinated with ES2B-C001+Montanide ISA 51, and 70% of mice vaccinated without adjuvant, remained tumor-free.

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The growing threat of drug-resistant bacteria is a global concern, highlighting the urgent need for new antibiotics and antibacterial strategies. In this light, practical synthetic access to natural product antibiotics can provide important structure-activity insights while also opening avenues for the development of novel analogues with improved properties. To this end, we report an optimised synthetic route for the preparation of the clinically used macrocyclic peptide antibiotic bacitracin.

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The continued rise of antibiotic resistance is a global concern that threatens to undermine many aspects of modern medical practice. Key to addressing this threat is the discovery and development of new antibiotics that operate by unexploited modes of action. The so-called calcium-dependent lipopeptide antibiotics (CDAs) are an important emerging class of natural products that provides a source of new antibiotic agents rich in structural and mechanistic diversity.

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Article Synopsis
  • Nicotinamide N-methyltransferase (NNMT) converts nicotinamide into 1-methylnicotinamide using SAM, and its role in health and diseases like cancer, diabetes, and obesity is under investigation as a potential therapeutic target.
  • * Recent studies utilized mRNA display screening to identify macrocyclic peptides that effectively bind to NNMT, showing strong inhibitory effects with low IC values (as low as 229 nM).
  • * The identified cyclic peptides were found to downregulate MNA production in cells and are unique as they do not compete with existing substrates, suggesting they are the first allosteric inhibitors of NNMT.
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A recently discovered bisubstrate inhibitor of Nicotinamide -methyltransferase (NNMT) was found to be highly potent in biochemical assays with a single digit nanomolar IC value but lacking in cellular activity. We, here, report a prodrug strategy designed to translate the observed potent biochemical inhibitory activity of this inhibitor into strong cellular activity. This prodrug strategy relies on the temporary protection of the amine and carboxylic acid moieties of the highly polar amino acid side chain present in the bisubstrate inhibitor.

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Nicotinamide -methyltransferase (NNMT) methylates nicotinamide (vitamin B3) to generate 1-methylnicotinamide (MNA). NNMT overexpression has been linked to a variety of diseases, most prominently human cancers, indicating its potential as a therapeutic target. The development of small-molecule NNMT inhibitors has gained interest in recent years, with the most potent inhibitors sharing structural features based on elements of the nicotinamide substrate and the -adenosyl-l-methionine (SAM) cofactor.

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The synthesis of a new class of benzotriazole-derived α-amino acid is described using a highly efficient nucleophilic aromatic substitution of -fluoronitrobenzenes with l-3-aminoalanine and a polymer-supported nitrite reagent-mediated diazotization and cyclization of the subsequent 1,2-aryldiamines as the key steps. Further functionalization of the benzotriazole unit by preparation of halogenated analogues and Suzuki-Miyaura cross-coupling with aryl boronic acids allowed the synthesis of α-amino acids with conjugated side chains. Analysis of the photophysical properties of these α-amino acids revealed that incorporation of electron-rich substituents results in charge-transfer-based, fluorescent compounds with MegaStokes shifts.

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Microbial synthesis of medium chain aliphatic hydrocarbons, attractive drop-in molecules to gasoline and jet fuels, is a promising way to reduce our reliance on petroleum-based fuels. In this study, we enabled the synthesis of straight chain hydrocarbons (C7-C13) by yeast Saccharomyces cerevisiae through engineering fatty acid synthases to control the chain length of fatty acids and introducing heterologous pathways for alkane or 1-alkene synthesis. We carried out enzyme engineering/screening of the fatty aldehyde deformylating oxygenase (ADO), and compartmentalization of the alkane biosynthesis pathway into peroxisomes to improve alkane production.

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Background: Anti-angiogenic therapies, targeting VEGF, are a promising treatment for hepatocellular carcinoma (HCC). To enhance this potential therapy, identification of novel targets in this pathway is of major interest. Nitric oxide (NO) plays a crucial role in VEGF-dependent angiogenesis.

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Background: Low catalytic activities of pathway enzymes are often a limitation when using microbial based chemical production. Recent studies indicated that the enzyme activity of aldehyde decarbonylase (AD) is a critical bottleneck for alkane biosynthesis in Saccharomyces cerevisiae. We therefore performed functional screening to identify efficient ADs that can improve alkane production by S.

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Article Synopsis
  • Scientists are trying to make special chemicals called phenylpropanoids, like flavonoids, using yeast, which is a type of fungus.
  • They found that an enzyme called Tsc13, which is important for making fats, is also causing problems by producing an unwanted chemical during this process.
  • By making small changes to Tsc13 and using a similar gene from plants, they were able to keep making the good chemicals without creating the unwanted ones.
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Establishing efficient synthetic pathways for microbial production of biochemicals is often hampered by competing pathways and/or insufficient precursor supply. Compartmentalization in cellular organelles can isolate synthetic pathways from competing pathways, and provide a compact and suitable environment for biosynthesis. Peroxisomes are cellular organelles where fatty acids are degraded, a process that is inhibited under typical fermentation conditions making them an interesting workhouse for production of fatty-acid-derived molecules.

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Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level production of free fatty acids (FFAs) in a yeast cell factory, and the production of alkanes and fatty alcohols from its descendants.

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Glutamine supplementation in specific groups of critically ill patients results in favourable clinical outcome. Enhancement of citrulline and arginine synthesis by glutamine could serve as a potential mechanism. However, while receiving optimal enteral nutrition, uptake and enteral metabolism of glutamine in critically ill patients remain unknown.

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Postoperative renal failure is a common complication after open repair of an abdominal aortic aneurysm. The amino acid arginine is formed in the kidneys from its precursor citrulline, and citrulline is formed from glutamine in the intestines. Arginine enhances the function of the immune and cardiovascular systems, which is important for recovery after surgery.

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Background: Jejunal feeding is preferred instead of gastric feeding in patients who are intolerant to gastric feeding or at risk of aspiration. However, the impact of gastric feeding compared with that of jejunal feeding on postprandial circulating plasma glucose and amino acid concentrations and the associated endocrine response in vivo in humans remains largely unexplored.

Objective: We compared the impact of administering enteral nutrition as either gastric feeding or jejunal feeding on endocrine responses in vivo in humans.

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Background: Dietary protein is required to attenuate the loss of muscle mass and to support recovery during a period of hospitalization. Jejunal feeding is preferred over gastric feeding in patients who are intolerant of gastric feeding. However, the impact of gastric vs.

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Unlabelled: Supplementation with arginine in combination with atorvastatin is more efficient in reducing the size of an atherosclerotic plaque than treatment with a statin or arginine alone in homozygous Watanabe heritable hyperlipidemic (WHHL) rabbits. We evaluated the mechanism behind this feature by exploring the role of the arginine/asymmetric dimethylarginine (ADMA) ratio, which is the substrate and inhibitor of nitric oxide synthase (NOS) and thereby nitric oxide (NO), respectively.

Methods: Rabbits were fed either an arginine diet (group A, n = 9), standard rabbit chow plus atorvastatin (group S, n = 8), standard rabbit chow plus an arginine diet with atorvastatin (group SA, n = 8) or standard rabbit chow (group C, n = 9) as control.

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Malignancies induce disposal of arginine, an important substrate for the immune system. To sustain immune function, the tumor-bearing host accelerates arginine's intestinal-renal axis by glutamine mobilization from skeletal muscle and this may promote cachexia. Glutamine supplementation stimulates argi-nine production in healthy subjects.

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