[Mechanism of VPS26 gene promoting implant osseointegration through Wnt/ß-catenin pathway in hyperlipidemia rats].

Objective: To investigate the mechanism of VPS26 effect on osteogenesis and adipogenesis differentiation of rat bone marrow mesenchymal stem cells (BMSC) in high fat environment, and to explore the effect of VPS26 on implants osseointegration of high fat rats and ectopic osteogenesis in nude mice. Methods: BMSC were cultured under normal osteogenic induction (osteogenic group) and high-fat osteogenic induction (high-fat group).High-fat group was transfected with VPS26 enhancer and inhibitor, and the expression levels of osteogenesis related genes and adipogenesis related genes were examined. Osteogenesis and adipogenesis of BMSC were detected by alkaline phosphatase (ALP) staining and oil red O staining after 7 and 14 days of induction.In osteogenic group,the binding of VPS26 to ß-catenin was detected by immunofluorescence staining and immunoprecipitation, and dual luciferase reporter assay (TOP Flash) was used to analyze the TOP/FOP ratio. Eighteen male 12-week hyperlipidemic Wista rats (160-200 g) were implanted with implants, and six in each group were injected with VPS26 overexpression lentivirus (LV-VPS26 group), negative control lentivirus (LV-nc group) and saline (blank control group).Micro-CT analysis , HE and oil red O staining were used to evaluate the osseointegration of the implants and lipid droplets formation of the femur samples. Twenty female 6-week nude mice (30-40 g) were divided into five groups and subcutaneously implanted with osteogenic BMSC non-transfected and transfected LV-VPS26, LV-nc, shVPS26, and shscr lentivirus on the back. Samples were used to observe ectopic osteogenesis. Results: The mRNA expression levels of ALP in the high-fat group BMSC after overexpression of VPS26 (1.56±0.09) were significantly higher than those of the negative control (1.01±0.03) (t=10.09, P<0.001), while those of peroxisome proliferator-activated receptor-γ (PPAR-γ) (t=6.44, P<0.001) and fatty acid-binding protein4 (FABP4) (t=10.01, P<0.001) were lower than those of the negative control. Western blotting results showed that compared with the negative control, protein expression of ALP and Runt-related transcription gene 2 was enhanced in the high-fat group BMSC after overexpression of VPS26 while PPAR-γ and FABP4 were inhibited. ALP activity of BMSC in the high-fat group was stronger after overexpression of VPS26, and the formation of lipid droplets was weaker than that in negative control. The results of immunofluorescence, immunoprecipitation and dual luciferase reporter assays showed co-localization and interaction of VPS26 with ß-catenin and a significant 43.10% increase in the TOP/FOP ratio (t=-3.17, P=0.034). VPS26 overexpression enhanced osseointegration and decreased the number of lipid droplets in high-fat rat and enhanced ectopic osteogenesis of nude mice. Conclusions: VPS26 activated osteogenesis differentiation and inhibited adipogenic differentiation of BMSCs through Wnt/ß-catenin pathway, promoting osseointegration of high-fat rat implants and ectopic osteogenesis of nude mice.

Streptomyces-derived actinomycin D inhibits biofilm formation via downregulating ica locus and decreasing production of PIA in Staphylococcus epidermidis.

AIM: The objective of this study was to investigate the biofilm inhibitory activity of Streptomyces-derived actinomycin D against biofilm formation by Staphylococcus epidermidis. METHODS AND RESULTS: The microtitre plate method and microscopy were used to detect the biofilm formation of S. epidermidis. And an attempt was made to detect the effect of actinomycin D on important biofilm components, exopolysaccharides (EPS) in S. epidermidis using precolumn derivation HPLC. Also cell surface hydrophobicities of S. epidermidis were assessed to explore action mechanisms. The qPCR was performed to demonstrate the genetic mechanisms of biofilm formation by S. epidermidis. Unlike other antibiotics, actinomycin D (1·5 µg ml-1 ) from Streptomyces luteus significantly inhibited biofilm formation by S. epidermidis. Additionally, it effectively inhibited S. epidermidis cells from adhering to glass slides. Actinomycin D downregulated ica locus and then the reduced polysaccharide intercellular adhesin production caused S. epidermidis cells to become less hydrophobic, thus supporting its anti-biofilm effect. CONCLUSION: Streptomyces-derived actinomycin D is active in inhibiting the biofilm formation of S. epidermidis. SIGNIFICANCE AND IMPACT OF THE STUDY: Actinomycin D can be used as a promising antibiofilm agent in inhibiting S. epidermidis biofilm formation. The study is also the first insight into how actinomycin D inhibited the biofilm formation of S. epidermidis. Actinomycin D could potentially be used to reduce the risk of biofilm-associated infections. Our study also suggests that the metabolites from Actinomycete strains keep further attention as potential antibiofilm agents against biofilm formation of S. epidermidis, even biofilm infections of the other bacteria.

Association of CYP1B1 gene polymorphisms and the positive expression of estrogen alpha and estrogen beta with endometrial cancer risk.

To investigate the relationship between the CYP1B1 L432V polymorphism, ERalpha and ERbeta positivities and the incidence of endometrial cancer. The relationship between CYP1B1 L432V polymorphism, ERalpha and ERbeta positivities and endometrial cancer was investigated using the allele-specific polymerase chain reaction method to analyze gene polymorphism in exon 3 codon 432 (C-G) of CYP1B1. Our results are as follows: in endometrial cancer cases the prevalence rates of CYP1B1 L432V genotypes C/C, C/G, and G/G were 47.2%, 36.1%, and 16.7%, respectively, and 68.8%, 23.8% and 7.5% in the control group, respectively. The frequencies of CYP1B1 C and G alleles were 65.3% and 34.7% in endometrial cancer patients and 80.6% and 19.4% in the control group. A significant difference was found in the genotype distributions or allele frequencies of CYP1B1 L432V polymorphism between the two groups (p < 0.05). Compared with wild-type C/C, the susceptibility of endometrial cancer with homozygotic mutation G/G and heterozygotic mutation C/G increased by 3.235 (95%CI 1.111-9.425) and 2.214 (95% CI 1.067-4.593). Moveover, the positive expression of ERalpha in genotypes G/G and C/G was higher than in the wild genotype C/C (p < 0.05). In conclusion, allelic polymorphism of CYP1B1 L432V increases the risk of endometrial cancer and has a positive correlation with ERalpha expression.

Novel modifications to the farnesyl moiety of the a-factor lipopeptide pheromone from Saccharomyces cerevisiae: a role for isoprene modifications in ligand presentation.

The a-factor of Saccharomyces cerevisiae is a dodecapeptide pheromone [YIIKGVFWDPAC(farnesyl)-OCH3] in which posttranslational modification with a farnesyl isoprenoid and carboxymethyl group is required for full biological activity. Utilizing novel synthetic techniques and a well-characterized array of biological assays, we prepared original modifications to the farnesyl moiety of the pheromone in order to assess the importance of this part of the lipopeptide for biological activity. Specifically, the 3-methyl group was replaced to create analogs containing the ethyl, vinyl, tert-butyl, and phenyl moieties at the 3-position of the farnesyl chain. Subsequent biological analyses demonstrated that all of these modifications render an active pheromone, with the vinyl and ethyl analogs exhibiting higher activity than the native a-factor. However, the level of activity varied with the modification; the bulkier and more hydrophobic groups (tert-butyl and phenyl) exhibited lower biological activity than the smaller moieties (ethyl and vinyl). Furthermore, two analogs with phenyl substitutions that differ only in the presumed isomerization of the allylic double bond show up to an 8-fold difference in bioactivity. It has previously been surmised that the role of isoprenoid additions is solely to target the attached polypeptides to membranes by increasing their hydrophobicity. However, these studies demonstrate that even modest structural changes to the isoprenoid can significantly affect biological activity. These results are clearly inconsistent with a simple hydrophobic role for the isoprenoid and instead illustrate that it plays an active role in mediating optimal a-factor/receptor interaction.

Design and synthesis of chiral and racemic phosphonate-based haptens for the induction of aldolase catalytic antibodies.

A novel strategy for the generation of aldolase catalytic antibodies, based on the use of antibody-catalyzed enol ester hydrolysis as a 'trigger' to generate a reactive enolate intermediate, is described. A model system to test this strategy was developed and substrate 8 was synthesized. However, the targeted bifunctional haptens 11 and 33 were synthetically inaccessible, and therefore the alternative phosphonate hapten 39 was prepared. The key step in the synthesis of 39 was the direct generation of an unprotected phosphonate precursor via coupling of the secondary alcohol 37 with CH3P(O)Cl2. The chiral counterpart of hapten 39 was also synthesized from alcohol 46, prepared by Corey's asymmetric reduction method. One polyclonal antibody preparation generated from 39 appeared to catalyze the hydrolysis of the secondary acetate 49, but not the desired aldol cyclization of 8. Possible rationales for this finding are discussed.

[Studies on pyridonecarboxylic acids as antibacterial agents. VIII. Synthesis and structure-activity relationships of 1-(P-fluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl) cinnoline-3-carboxylic acid and analogues].

1-(P-fluorophenyl)-6-fluoro-1,4-oxo-7-(1-piperazinyl) cinnoline-3-carboxylic acid and its quinoline, 1,8-naphthyridine and pyrido (2,3-c) pyridazine analogues were prepared for studies of structure-activity relationships. The antibacterial activities of these 16 compounds were tested and the values of their electron densities were calculated using Hückel molecular orbital theory method. The results showed that the electron densities on the oxygen atoms of 3-carboxyl and 4-oxo have influenced strongly antibacterial activity in vitro. The quinolines and 1,8-naphthyridines showed higher electron densities and more potent antibacterial activities in vitro. The cinnolines and pyrido (2,3-c) pyridazines showed lower electron densities and lower or no antibacterial activities in vitro.

[PSD-007 luminescence in the diagnosis of exfoliative cells from malignant tumors].

This paper presents the first report in China on the use of luminescence method with hematoporphyrin derivative PSD-007 in the analysis of the exfoliative malignant cells. By this method, pleurorrhea and ascites from 226 suspicious patients were detected. The results showed that its positive rate was 42.23% higher than that of Wright's stain and its positive conformation rate to HE stain could reach as high as 90.2%. Especially, cancer cells could be distinguished from various kinds of non-cancer cells by an objective quantitative analysis of the cellular fluorescent intensity using microfluorophotometer. This new method, being simple, economical and highly specific, is used not only in the qualitative study of the exfoliative tumor cells, but also in the quantitative analysis.