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.
A high-quality reference genome is necessary to determine the molecular mechanisms underlying important biological phenomena; therefore, in the present study, a chromosome-level genome assembly of the Chinese shrimp Fenneropenaeus chinensis was performed. Muscle of a male shrimp was sequenced using PacBio platform, and assembled by Hi-C technology. The assembled F. chinensis genome was 1.47 Gb with contig N50 of 472.84 Kb, including 57.73% repetitive sequences, and was anchored to 43 pseudochromosomes, with scaffold N50 of 36.87 Mb. In total, 25,026 protein-coding genes were predicted. The genome size of F. chinensis showed significant contraction in comparison with that of other penaeid species, which is likely related to migration observed in this species. However, the F. chinensis genome included several expanded gene families related to cellular processes and metabolic processes, and the contracted gene families were associated with virus infection process. The findings signify the adaptation of F. chinensis to the selection pressure of migration and cold environment. Furthermore, the selection signature analysis identified genes associated with metabolism, phototransduction, and nervous system in cultured shrimps when compared with wild population, indicating targeted, artificial selection of growth, vision, and behavior during domestication. The construction of the genome of F. chinensis provided valuable information for the further genetic mechanism analysis of important biological processes, and will facilitate the research of genetic changes during evolution. 相似文献
Clinical platelet infusion is primarily used to prevent or stop bleeding, but can also have a role in treating infections or promoting wound healing. The demand for platelets has increased in recent years. However, as platelets can only be stored for short periods, there is a substantial loss due to the products reaching their expiry date. Platelet lyophilization is a particularly valuable and important research field. The purpose of studying the freeze-drying preservation of platelets is to realize the long-term preservation of platelets at room temperature. It is very possible to prepare qualified freeze-dried platelets. However, there are still problems that have not been solved in the process of platelet lyophilization. This review mainly summarizes research progress in the preparation and application of freeze-dried platelets. 相似文献
Presented is an antibody production platform based on the fed-batch culture of recombinant NS0-derived cell lines. NS0 host cells, obtained from the European Collection of Cell Cultures (ECACC, Salisbury, UK, Part No. 85110503), were first adapted to grow in a protein-free, cholesterol-free medium. The resulting host cell line was designated NS0-PFCF (protein-free, cholesterol-free). The five production cell lines presented here were generated using a common protocol consisting of transfection by electroporation and subcloning. The NS0-PFCF host cell line was transfected using a single expression vector containing the Escherichia coli xanthine-guanine phosphoribosyl transferase gene (gpt), and the antibody heavy and light chain genes driven by the CMV promoter. The five cell lines were chosen after one to three rounds of iterative subcloning, which resulted in a 19-64% increase in antibody productivity when four mother-daughter cell pairs were cultured in a fed-batch bioreactor process. The production cell lines were genetically characterized to determine antibody gene integrity, nucleotide sequences, copy number, and the number of insertion sites in the NS0 cell genome. Genetic characterization data indicate that each of the five production cell lines has a single stably integrated copy of the antibody expression vector, and that the antibody genes are correctly expressed. Stability of antibody production was evaluated for three of the five cell lines by comparing the early stage seed bank with the Working Cell Bank (WCB). Antibody productivity was shown to be stable in two of three cell lines evaluated, while one of the cell lines exhibited a 20% drop in productivity after passaging for approximately 4 weeks. These five NS0-derived production cell lines were successfully cultured to produce antibodies with acceptable product quality attributes in a standardized fed-batch bioreactor process, consistently achieving an average specific productivity of 20-60 pg/cell-day, and a volumetric productivity exceeding 120 mg/L-day (Burky et al., 2006). In contrast to the commonly available NS0 host cell line, which requires serum and cholesterol for growth, and the commonly used expression vector system, which uses a proprietary glutamine synthetase selection marker (GS-NS0), these NS0 cells are cholesterol-independent, grow well in a protein-free medium, use a non-proprietary selection marker, and do not require gene amplification for productivity improvement. These characteristics are advantageous for use of this NS0 cell line platform for manufacturing therapeutic antibodies. 相似文献
The major aim of the project was to develop the virus-like particles (VLPs) displaying single or multi-epitope of hepatocellular carcinomas (HCC) in Escherichia coli and to evaluate the effect on inducing Ag-specific CD8(+) T cell response and antitumor efficacy as candidate vaccines. To this end, hepatitis B virus core (HBc) particles were used as a carrier of HCC epitopes. Four HCC epitopes MAGE-1(278-286aa), MAGE-3(271-279aa), AFP1 (158-166aa) or AFP2 (542-550aa) were fused to the 3' terminus of the truncated HBV core gene, respectively, or conjunctively. Not all recombinant plasmids led to expression of chimeric proteins in expression strain E. coli BL21 (DE3), but chimeric proteins which are expressed in inclusion bodies resulted in the formation of complete "mature" VLPs. E. coli-derived truncated HBc(1-144) chimeric protein self-assembled into VLPs that both morphologically and physically are similar to the wild-type ones and they still remained activity after purification and refolding from 6M urea solution. We also showed that they could be internalized and presented by DCs in vitro. Additionally, DCs pulsed with the chimeric HBc-VLPs could induce stronger CTL activity and greater IFN-gamma secretion by responding T cells compared with peptid-pulsed DCs. In the B16-pIR-HH tumor therapy model, the growth of established tumors was significantly inhibited by immunization using VLP-pulsed DCs, resulting in significantly higher survival rate of immunized animals. Thus, the results of the current study have demonstrated the principal possibility of using VLP on the basis of HBcAg for creation of a new type of HCC-specific immunogen. 相似文献