ClpA affects the virulence of Paracidovorax citrulli on melon by regulating RepA.

ClpA is a widely conserved protease in bacteria that plays a key role in virulence. To investigate its specific mechanism of action in the pathogenicity of Paracidovorax citrulli (formerly Acidovorax citrulli), we constructed a ClpA deletion mutant, ΔClpA. The ΔClpA mutant of P. citrulli displayed reduced virulence on melon seedlings, and reduced motility, swarming ability, and antioxidant capacity. On the other hand, the ClpA deletion of P. citrulli mutant reduced the resistance to elevated temperature and enhanced biofilm formation ability. Using qRT-PCR, we observed that ClpA negatively regulates the expression of the virulence-related genes virB, pilR, pilA, and fliM, while positively regulating hrpG, hrcQ, and trbC. Bacterial double hybrid and Glutathione-S-transferase pulldown (GST-pulldown) results showed that ClpA interacts directly with RepA, and negatively regulates the expression of RepA. After deletion of the RepA gene, the pathogenicity of P. citrulli was lost, biofilm formation ability was enhanced, and the expression of hrpG, pilR, and trbC was positively regulated. These results indicate that ClpA plays a key role in the regulation of several virulence traits of P. citrulli, paving the way for future studies to better elucidate the virulence mechanisms of this bacterial plant pathogen.

Mechanism of action of sterol regulatory element-binding proteins in nonalcoholic fatty liver disease and related therapeutic targets / 临床肝胆病杂志

Nonalcoholic fatty liver disease （NAFLD） has become the most common liver disease in the world and is an important risk factor for the progression to hepatocellular carcinoma. However， the pathogenesis of NAFLD remains unclear， and there is still a lack of specific treatment measures. Sterol regulatory element-binding proteins （SREBP） are an important nuclear transcription factor， which mainly maintains the balance of lipid metabolism inside the body by activating the genes associated with the synthesis and uptake of cholesterol， fatty acids， and triglycerides， and therefore， SREBP are a target for the treatment of metabolic diseases. This article reviews the latest advances in SREBP in the pathogenesis of NAFLD and the latest evidence of SREBP-targeted therapy for NAFLD. It is worth noting that recent studies have shown that SREBP inhibition can cause liver injury together with autophagy damage. Therefore， excessive inhibition of lipogenesis may exert a counterproductive effect on the treatment of NAFLD. In conclusion， SREBP is a promising therapeutic target for NAFLD； the molecular mechanism of SREBP in lipid metabolism is regulated by many factors， and these factors are being deeply explored and analyzed， which has an important clinical significance for the treatment of NAFLD.

Biocontrol potential of Burkholderia sp. BV6 against the rice blast fungus Magnaporthe oryzae.

AIM: To investigate the broad-spectrum antifungal activity of Burkholderia sp. BV6, that is isolated from rice roots and its biocontrol potential against rice blast caused by Magnaporthe oryzae. METHODS AND RESULTS: We evaluated the ability to isolate BV6 in the biological control of rice blast disease and investigated its antifungal mechanisms. BV6 strongly inhibited the hyphal growth of M. oryzae Guy11 and other plant pathogenic fungi, and pot experiments showed that BV6 significantly decreases the disease index of rice blast from 47.5 to 24.6. The secreted small-molecule secondary metabolites were regarded as weapons during the antifungal process by inhibiting the germination of M. oryzae conidia and mycelial growth, and thereby prevent the following infection. Liquid chromatography-mass spectrometry analysis of the metabolites from the supernatant of isolate BV6 showed that the antifungal weapons of isolate BV6 are novel, small, molecular hydrophilic compounds that are different from reported antifungal compounds. CONCLUSIONS: The isolate BV6 inhibits the M. oryzae infection by the production of small-molecule antifungal compounds. SIGNIFICANCE AND IMPACT OF THE STUDY: The current study discovers the role of the Burkholderia sp. BV6 in the biocontrol of plant pathogenic fungi. Therefore, isolate BV6 is a potential candidate for developing a microbial formulation for the biocontrol of the most common disease of rice blast.

Research progress in the characterization of protein adsorption on biomaterial surface / 国际生物医学工程杂志

The characterization methods in the field of protein adsorption on biological materials in recent years were reviewed from the aspects of protein adsorption amount, adsorption layer thickness, molecular conformational change after protein adsorption, molecular morphology after protein adsorption, and protein molecule adsorption process simulation. These methods include biochemical analysis, surface plasmon resonance (SPR), dissipative quartz crystal microbalance ( QCM-D ) , ellipsometry ( ELM ) , optical interference reflection ( RIFS ) , attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), circular dichroism (CD), atomic force microscopy ( AFM ) and computer molecular simulation techniques . In this paper , the basic principles , the advantages and disadvantages of the above characterization methods and related researches were reviewed. This paper provides a comprehensive and reliable basis for the selection of protein experimental characterization methods in protein adsorption, biomaterial design and other research, and provides new ideas for research in the field of protein.