Bacterial infections caused by Gram-negative pathogens represent a growing burden for public health worldwide. Despite the urgent need for new antibiotics that effectively fight against pathogenic bacteria, very few compounds are currently under development or approved in the clinical setting. Repurposing compounds for other uses offers a productive strategy for the development of new antibiotics. Here we report that the multifaceted melatonin effectively improves survival rates of mice and decreases bacterial loads in the lung during infection. Mechanistically, melatonin specifically inhibits the activity of citrate synthase of Gram-negative pathogens through directly binding to the R300, D363, and H265 sites, particularly for the notorious Pasteurella multocida. These findings highlight that usage of melatonin is a feasible and alternative therapy to tackle the increasing threat of Gram-negative pathogen infections via disrupting metabolic flux of bacteria.
Science China Life Sciences - Human alpha-2-macroglobulin is a well-known inhibitor of a broad spectrum of proteases and plays important roles in immunity, inflammation, and infections. Here, we... 相似文献
Heavy metals, that is Cu(II), are harmful to the environment. There is an increasing demand to develop inexpensive detection methods for heavy metals. Here, we developed a yeast biosensor with reduced-noise and improved signal output for potential on-site copper ion detection. The copper-sensing circuit was achieved by employing a secondary genetic layer to control the galactose-inducible (GAL) system in Saccharomyces cerevisiae. The reciprocal control of the Gal4 activator and Gal80 repressor under copper-responsive promoters resulted in a low-noise and sensitive yeast biosensor for copper ion detection. Furthermore, we developed a betaxanthin-based colorimetric assay, as well as 2-phenylethanol and styrene-based olfactory outputs for the copper ion detection. Notably, our engineered yeast sensor confers a narrow range switch-like behaviour, which can give a ‘yes/no’ response when coupled with a betaxanthin-based visual phenotype. Taken together, we envision that the design principle established here might be applicable to develop other sensing systems for various chemical detections. 相似文献
Probiotics and Antimicrobial Proteins - Gastrointestinal mucositis associated with the use of chemotherapeutic drugs can seriously affect the quality of life of patients. In this study, a probiotic... 相似文献
In this study, the interaction between cytidine and human serum albumin (HSA) was investigated for the first time by fluorescence spectroscopy in combination with UV absorption spectrum and molecular modeling under simulative physiological conditions. Experimental results indicated that cytidine had a strong ability to quench the intrinsic fluorescence of human serum albumin. The binding constants (K) at different temperatures, thermodynamic parameter enthalpy changes (DeltaH) and entropy changes (DeltaS) of HSA-cytidine had been calculated according to the relevant fluorescence data, which indicated that the hydrophobic and electrostatic interactions played a major role, which was in agreement with the results of molecular modeling study. In addition, the effects of other ions on the binding constants were also studied. Furthermore, synchronous fluorescence technology was successfully applied to the determination of human serum albumin added into the cytidine solution. 相似文献
Neurotrophins, such as brain derived neurotrophic factor (BDNF), do not cross the blood-brain barrier (BBB). Certain monoclonal antibodies (MAb) to the human insulin receptor (HIR) do cross the BBB via receptor-mediated transport, and can act as a molecular Trojan horse to ferry across the BBB an attached drug. A genetically engineered fusion protein was produced whereby the amino terminus of human BDNF is fused to the carboxyl terminus of the heavy chain of a chimeric HIRMAb. The HIRMAb-BDNF fusion protein reacted equally with antibodies to human IgG and BDNF. The bi-functionality of the fusion protein was retained as the affinity of the fusion protein for the HIR was identical to that of the chimeric HIRMAb, and the affinity of the fusion protein for the trkB receptor was identical to that of BDNF. The fusion protein was equi-potent with BDNF in a neuroprotection assay in human neural cells. The pharmacokinetics (PK) of the fusion protein was examined in the adult Rhesus monkey. The mean residence time (MRT) of the fusion protein in blood was >100-fold longer than the MRT of BDNF. Therapeutic levels of BDNF were produced in primate brain following the intravenous administration of the fusion protein. A fusion protein tandem vector was engineered that allowed for isolation of a CHO cell line that produced the fusion protein at high levels in serum free medium. Neurotrophins, such as BDNF, can be re-formulated to enable these molecules to cross the human BBB, and such fusion proteins represent a new class of human neurotherapeutics. 相似文献