Gut dysbiosis and bile acid (BA) metabolism disturbance are involved in the pathogenesis of ulcerative colitis. This study aimed to investigate the effect of fucoidan on BA metabolism and gut microbiota in dextran sulfate sodium-induced colitis mice. Our results showed that fucoidan effectively suppressed colonic inflammation and repaired the gut barrier. In addition, fucoidan increased the relative abundance of the Lachnospiraceae family, such as Turicibacter, Muribaculum, Parasutterella, and Colidextribacter, followed by an increase in short-chain fatty acids, especially in butyrate. Moreover, fucoidan modulated bile acid metabolism by elevating cholic acid, ursodeoxycholic acid, deoxycholic acid, and lithocholic acid and decreasing β-muricholic acid, which led to activation of FXR and TGR5 and further enhanced the gut barrier and suppressed colonic inflammation. Our results revealed that the effect of fucoidan alleviating colitis was largely mediated by gut microbiota, which was confirmed by the fecal transplantation experiment. Collectively, these findings provided the basis for fucoidan as a potential functional food for colitis.
Acetyl-CoA, the precursor of sex pheromone biosynthesis in Helicoverpa armigera, is generated from glycolysis. As the first speed-limited enzyme in glycolysis, Hexokinase (HK) plays an important role in acetyl-CoA production. However, the function of HK in sex pheromone production remains unclear. This study employed H. armigera as material to explore the role of HK in sex pheromone production. Results demonstrated that the transcription profile of HaHK in female moth pheromone glands (PGs) was consistent with the release fluctuation of sex pheromone. Interference of HaHK prevented the increase of acetyl-CoA content induced by PBAN. Therefore, knockdown of HaHK in female PGs caused significant decreases in (Z)-11-hexadecenal (Z11-16:Ald) production, female capability to attract males, and mating rate. Furthermore, sugar feeding (5% sugar) increased the transcription and enzymatic activity of HK. Pheromone biosynthesis activating neuropeptide (PBAN) signal phospho-activated HaHK in PGs and Sf9 cells via protein kinase A (PKA), as shown by pharmacological inhibitor analysis. In general, our study confirmed that PBAN/cAMP/PKA signal activated HaHK, in turn promoted glycolysis to ensure the supply of acetyl-CoA, and finally facilitated sex pheromone biosynthesis and subsequent mating behavior.
To investigate the expression of tyrosine kinase B (trkB) in lung tissue of rats with lung injury induced by brain ischemia.Twenty six adult SD rats were divided into sham group and brain ischemia lung injury (BILI) group. All rats were sacrificed at 3 days after the operation of modeling, lung tissues were then harvested to measure the protein and mRNA level of trkB by the methods of western blot and RT-PCR, the location of trkB positive cells was observed by immunochemistry study.trkB mRNA level in the lung tissue of rats with brain ischemia presented a significant increase, in corresponding to the upregulation of BDNF protein levels, when compared with sham one (P<0.05). trkB was localized in endothelia cells and smooth muscle.The upregulated expression of trkB expression may be associated with lung injury after brain ischemia.
It is of great significance to develop a dietary intervention strategy to prevent inflammatory bowel disease (IBD). A millet-rich diet can ameliorate IBD, but the active ingredients and mechanisms remain to be studied. Our results showed that the oral administration of foxtail millet protein hydrolysates (FMPH) reduced the disease activity index (DAI) score and improved the colon symptoms of dextran sulfate sodium (DSS)-induced colitis mice. FMPH reduced the serum LPS level, increased intestinal ZO-1 and occludin expression, inhibited NF-κB phosphorylation, and reduced the levels of TNF-α and IL-6. Further, FMPH inhibited Th17 cell differentiation, and inhibited inflammasome activation and IL-1β expression through the NLRP3/ASC/caspase-1 pathway. The results on Caco-2 cells confirmed the role of FMPH on tight junction and inflammasomes activation. A total of 2620 peptides were identified in FMPH by UPLC-MS/MS, of which 22 peptides were predicted as potential biopeptides, and the key sequences were LPF, ANP, PY, YW, and IPP. This study supports the effect of a diet rich in millet on the improvement of IBD and provides a scientific basis for the use of millet protein as a functional food to improve intestinal inflammation.
Background.The enzymatic degradation of quorums sensing (QS) molecules (called quorum quenching, QQ) has been considered as a promising anti-virulence therapy to treat biofilm-related infections and combat antibiotic resistance.The recently-discovered QQ enzyme MomL has been reported to efficiently degrade different N-acyl homoserine lactones (AHLs) of various Gram-negative pathogens.Here we investigated the effect of MomL on biofilms formed by two important nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii.Methods.MomL was expressed in E.coli BL21 and purified.The activity of MomL on AHLs with hydroxyl substituent was tested.Biofilms of P. aeruginosa PAO1 and Acinetobacter strains were formed in 96-well microtiter plates.Biofilm formation was evaluated by crystal violet staining, plating and fluorescence microscopy.The effect of MomL on biofilm susceptibility to antibiotics was also tested.We further evaluated MomL in dual-species biofilms formed by P. aeruginosa and A. baumannii, and in biofilms formed in a wound model.The effect of MomL on virulence of A. baumannii was also tested in the Caenorhabditis elegans model.Results.MomL reduced biofilm formation and increased biofilm susceptibility to different antibiotics in biofilms of P. aeruginosa PAO1 and A. baumannii LMG 10531 formed in microtiter plates in vitro.However, no significant differences were detected in the dual-species biofilm and in wound model biofilms.In addition, MomL did not affect virulence of A. baumannii in the C. elegans model.Finally, the effect of MomL on biofilm of Acinetobacter strains seems to be straindependent.Discussion.Our results indicate that although MomL showed a promising anti-biofilm effect against P. aeruginosa and A. baumanii biofilms formed in microtiter plates, the effect on biofilm formation under conditions more likely to mimic the real-life situation was much less pronounced or even absent.Our data indicate that in order to obtain a better picture of potential applicability of QQ enzymes for the treatment of biofilm-related infections, more elaborate model systems need to be used.
A practical synthesis of the anti-methicillin resistant Staphylococcus aureus cephem (6R-trans)-E-7-[[[[2,5-dichloro-4-[3-[(carboxymethyl)amino]-3-oxo-1-propenyl]phenyl]-thio]-acetyl]amino]-4-[[(2-carboxy-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-2-en-3-yl)methyl]thio]-2,6-dimethyl-1-[3-(4-methylmorpholino-4-yl)propyl]-1-pyridinium, hydroxide, inner salt (BMS-247243) was developed. A process was developed for the interchange of the iodide counterion in 3a to chloride 3b that was essential for an efficient synthesis of the C-3 side chain 4-mercaptopyridone 6b. Use of catalytic Bu4NCl in the reaction of chlorocinnamide 14 with the Li-salt of methylthioglycolate formed the methyl ester of the C-7 side chain 12b in high yield. Reaction with the dianion of thioglycolic acid gave an increased level of the corresponding Michael addition byproduct that led to lower quality thermodynamic product 12b by the reverse reaction. Cephem nucleus 16 was acylated with the acid chloride of acid 12b in a biphasic system to circumvent the cumbersome workup involved in reactions mediated by carbodiimdes DCC or EDAC for the synthesis of diester 17. An unusual degradation product diacid 20 was obtained during the deprotection of diester 17 with TFA to amorphous diacid 19. Reaction of diacid 19 with 4-mercaptopyridone 6b formed BMS-247243 in moderate yield. Alternately, an efficient coupling of diester 17 with 4-mercaptopyridone 6b gave crystalline diester 21 with minimal (<1%) contamination of the double bond isomer 22. Double deprotection of diester 21 followed by crystallization furnished the double zwitterion BMS-247243 in high yield.
Quorum sensing (QS) is a population-dependent mechanism for bacteria to synchronize social behaviors such as secretion of virulence factors. The enzymatic interruption of QS, termed quorum quenching (QQ), has been suggested as a promising alternative anti-virulence approach. In order to efficiently identify QQ bacteria, we developed a simple, sensitive and high-throughput method based on the biosensor Agrobacterium tumefaciens A136. This method effectively eliminates false positives caused by inhibition of growth of biosensor A136 and alkaline hydrolysis of N-acylhomoserine lactones (AHLs), through normalization of β-galactosidase activities and addition of PIPES buffer, respectively. Our novel approach was successfully applied in identifying QQ bacteria among 366 strains and 25 QQ strains belonging to 14 species were obtained. Further experiments revealed that the QQ strains differed widely in terms of the type of QQ enzyme, substrate specificity and heat resistance. The QQ bacteria identified could possibly be used to control disease in aquaculture.
Background The enzymatic degradation of quorums sensing (QS) molecules (called quorum quenching, QQ) has been considered as a promising anti-virulence therapy to treat biofilm-related infections and combat antibiotic resistance. The recently-discovered QQ enzyme MomL has been reported to efficiently degrade different N -acyl homoserine lactones (AHLs) of various Gram-negative pathogens. Here we investigated the effect of MomL on biofilms formed by two important nosocomial pathogens, Pseudomonas aeruginosa and Acinetobacter baumannii . Methods MomL was expressed in E.coli BL21 and purified. The activity of MomL on AHLs with hydroxyl substituent was tested. Biofilms of P. aeruginosa PAO1 and Acinetobacter strains were formed in 96-well microtiter plates. Biofilm formation was evaluated by crystal violet staining, plating and fluorescence microscopy. The effect of MomL on biofilm susceptibility to antibiotics was also tested. We further evaluated MomL in dual-species biofilms formed by P. aeruginosa and A. baumannii , and in biofilms formed in a wound model. The effect of MomL on virulence of A. baumannii was also tested in the Caenorhabditis elegans model. Results MomL reduced biofilm formation and increased biofilm susceptibility to different antibiotics in biofilms of P. aeruginosa PAO1 and A. baumannii LMG 10531 formed in microtiter plates in vitro . However, no significant differences were detected in the dual-species biofilm and in wound model biofilms. In addition, MomL did not affect virulence of A. baumannii in the C. elegans model. Finally, the effect of MomL on biofilm of Acinetobacter strains seems to be strain-dependent. Discussion Our results indicate that although MomL showed a promising anti-biofilm effect against P. aeruginosa and A. baumanii biofilms formed in microtiter plates, the effect on biofilm formation under conditions more likely to mimic the real-life situation was much less pronounced or even absent. Our data indicate that in order to obtain a better picture of potential applicability of QQ enzymes for the treatment of biofilm-related infections, more elaborate model systems need to be used.
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