Crystal Violet Staining Assay Research Articles

Biofilm formation by Staphylococcus aureus isolates from a dental clinic in Konya, Turkey

The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes' detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.

Cytotoxic activity of fumonisin B1 in Vero cells: comparison between 2D and 3D structural microplates

The present study aimed to estimate cytotoxic activity of fumonisin B1 (FB1) in Vero cells using crystal violet staining assay (CVA) and lactate dehydrogenase assay (LDH) performed in flattened (2D) and three dimensional (3D) bottom (V, U, and M) microplates. Vero cells were exposed to different concentrations of FB1 ranging from 0 to 10 μg/ml for 24 and 48 h. Tween 20 was used as a positive control and acetonitrile 50% in water was used as a negative control. Results revealed that CVA could be performed in the F type microplate for 24 and 48 h but it was useless in the 3D microplates. LDH assay showed that FB1 induced significant cytotoxicity on Vero cells after 24 h exposure in all microplates. Using 3D bottom microplates allowed formation of spheroid cell aggregates and reduced cell adhesion. LDH release in the U type microplate showed a significant dose-dependent increase, while V type and M type microplates showed a significant dose-independent increase in all exposed cells. Forty-eight hours exposure to FB1 in 2D microplate induced time-related cytotoxicity in all exposed cells pronounced as increased percentage of dead cells and significant increase in LDH release at 0.01, 0.1, 1, and 10 μg/ml. It was concluded that 2D culture plate is suitable for both LDH and CVA while 3D microplates are suitable only for the LDH assay. LDH assay could detect the cytotoxic effect of FB1 at lower concentrations than crystal violet staining assay.

Membrane Fluidity Modulates Biofilm Formation in E. coli via the Rcs Phosphorelay

Lipid membranes are essential for the survival of any cell. The phase behavior of membranes is tightly regulated to maintain their physical integrity and their utility as protein scaffolds. The Escherichia coli inner membrane is composed mainly of three lipid species: phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin (CL). In vitro studies have shown that the presence of CL increases the fluidity of model membranes. Using real-time PCR, we have found that disruption of the three enzymes responsible for CL synthesis—ClsA, ClsB, and ClsC—causes activation of the Rcs signaling pathway. Confocal scanning laser microscopy (CLSM) shows that ΔclsABC biofilms grown under flow are significantly denser than their wild-type counterparts. These mutants also display decreased biofilm formation in crystal violet staining assays. Disruption of the Rcs pathway in a ΔclsABC background restores crystal violet staining to the level of wild-type or better, suggesting that increased Rcs activation is responsible for the observed effects on biofilm formation. We hypothesize the Rcs phosphorelay responds to changes in membrane fluidity, such as that caused by removal of CL from the inner membrane of E. coli.

Efficacy of silver/hydrophilic poly(p-xylylene) on preventing bacterial growth and biofilm formation in urinary catheters.

Catheter associated urinary tract infections (CAUTI), caused by several strains of bacteria, are a common complication for catheterized patients. This may eventually lead to a blockage of the catheter due to the formation of a crystalline or amorphous biofilm. Inhibiting bacteria should result in a longer application time free of complaints. This issue has been investigated using an innovative type of silver-coated catheter with a semipermeable cap layer to prevent CAUTI. In this work, two different types of silver catheters were investigated, both of which were capped with poly(p-xylylene) (PPX-N) and exhibited different surface properties that completely changed their wetting conduct with water. The contact angle of conventionally deposited PPX-N is approximately 80°. After O2 plasma treatment, the contact angle drops to approximately 30°. These two systems, Ag/PPX-N and Ag/PPX-N-O2, were tested in synthetic urine at a body temperature of 37 °C. First, the optical density and the inhibition zones of both bacteria strains (Escherichia coli and Staphylococcus cohnii) were examined to confirm the antibacterial effect of these silver-coated catheters. Afterward, the efficacy of silver catheters with different treatments of biofilm formed by E. coli and S. cohnii were tested with crystal violet staining assays. To estimate the life cycles of silver/PPX-catheters, the eluted amount of silver was assessed at several time intervals by anodic stripping voltammetry. The silver catheter with hydrophilic PPX-N coating limited bacterial growth in synthetic urine and prevented biofilm formation. The authors attribute the enhanced bacteriostatic effect to increased silver ion release detected under these conditions. With this extensive preparatory analytic work, the authors studied the ability of the two different cap layers (without silver), PPX-N and oxygen plasma treated PPX-N, to control the growth of a crystalline biofilm by measuring the concentrations of the Ca2+ and Mg2+ ions after exposure of the catheters to saturated urine for 24 h. The higher concentrations of Ca2+ and Mg2+ in the precipitates on the PPX-N catheters indicates that the hydrophilic PPX-N coating is superior to the simple PPX-N coating, with regard to the formation of a crystalline biofilm. Moreover, hydrophilic PPX-N as a cap layer may promote wettability and increase silver ion release rate and thus reduce the adhesion of suspended crystals to the catheter. Reduced bacterial growth and reduced adhesion may help to prevent CAUTI.

Inhibitory effect of oncolytic adenovirus ZD55-special AT rich sequence binding protein 1 on proliferation and invasion of andragon-independent prostate cancer DU145 cells

Objective To investigate the suppressive effect of oncolytic adenovirus ZD55-special AT rich sequence binding protein 1 (SATB1) expressing small hairpin RNA targeting SATB1 gene on growth and invasion of prostate cancer DU145 cells. Methods The oncolytic adenovirus ZD55-SATB1 was constructed and identifies. The inhibitory effect of ZD55-SATB1 on SATB1 expression was evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting analysis at 72 h after infection of DU145 cells with ZD55-SATB1 at a MOI of 10. The cytotoxicity of ZD55-SATB1 was detected by cell counting kit-8 (CCK-8) assay and crystal violet staining assay. Cell invasion was detected by Matrigel invasion assay. The expression of E1A protein in DU145 cell lines infected with viruses respectively was detected by Western blotting. Results The oncolytic adenoviruses ZD55-SATB1 were successfully constructed and identified. RT-PCR and Western blotting assay showed that ZD55-SATB1 could significantly decrease the expression of SATB1 in DU145 cells (P<0.05). The relative protein levels of E1A in DU145 cells treated with ZD55-SATB1 were significantly higher than those in human normal prostate epithelial cell line PZ-HPV-7 cells (P<0.01), which indicated cancer specificity of ZD55-SATB1 for prostate cance cells. Crystal violet staining assay showed that ZD55-SATB1 exhibited obvious cytotoxicity in DU145 cells. The cytopathic effect of ZD55-SATB1 was much stronger than that of ZD55-enhanced green fluorescent protein (EGFP) and Ad-SATB1. CCK-8 assay showed that cell viability of ZD55-SATB1 group [(31.60±3.31)%] was significantly lower than that in ZD55-EGFP group [(61.70±2.42)%, P=0.025] and Ad-SATB1 group [(82.40±3.54)%, P=0.017] for DU145 cells after 4 days. Transwell cell invasive experiment showed that the number of cells that invaded the membrane in ZD55-SATB1 group was (61.30±17.25) cells, significantly less than that in the Ad-SATB1 group [(170.10±25.44) cells, P=0.043], the ZD55-EGFP group [(295.40±23.36) cells, P=0.013] and the PBS group [(490.50±33.36) cells, P=0.009]. Conclusion Oncolytic adenovirus ZD55-SATB1 could effectively knockdown the SATB1 expression in DU145 cells, and dramatically inhibit proliferation and invasion of DU145 cells. Key words: Oncolytic adenovirus; Special AT rich sequence binding protein 1; Proliferation; Invasion

Anti-Melanoma Activities of Haspin Inhibitor CHR-6494 Deployed as a Single Agent or in a Synergistic Combination with MEK Inhibitor.

Background: Melanoma is a heterogeneous malignancy that presents an immense challenge in therapeutic development. Recent approaches targeting the oncogenic MAP kinase pathways have shown tremendous improvement in the overall survival of patients with advanced melanoma. However, there is still an urgent need for identification of new strategies to overcome drug resistances and to improve therapeutic efficacy. Haspin (Haploid Germ Cell-Specific Nuclear Protein Kinase) belongs to a selected group of mitotic kinases and is required for normal mitosis progression. In contrast to inhibitors of other mitotic kinases, anti-tumor potential of haspin inhibitors has not been well explored. Herein, we aim to examine effects of CHR-6494, a small molecule inhibitor of haspin, in melanoma cells.Methods: Anti-tumor activities of the haspin inhibitor CHR-6494 were tested in a number of melanoma cell lines either as a single agent or in combination with the MEK inhibitor Trametinib (GSK1120212). Experiments are based on: 1) Cell viability determined by the crystal violet staining assay; 2) apoptotic responses measured by the caspase 3/7 activity assay and western blot analysis for the level of cleaved PARP (Poly ADP-Ribose Polymerase); 3) cell cycle analysis conducted using flow cytometry; and 4) cell migratory ability assessed by the scratch assay and the transwell migration assay.Results: We have found that CHR-6494 alone elicits a dose dependent inhibitory effect on the viability of several melanoma cell lines. This growth inhibition is accompanied by an increase in apoptotic responses. More importantly, CHR-6494 appears to synergize with the MEK inhibitor Trametinib in suppressing cell growth and enhancing apoptosis in both wild type and BRAFV600E mutant melanoma cell lines. Administering of these two small molecules as a combination is also capable of suppressing cell migration to a greater extent than the individual agent.Conclusion: These results suggest that haspin can be considered as a viable anti-melanoma target, and that concomitant inhibition of haspin and MEK activities with small molecules could represent a novel therapeutic strategy with improved efficacy for treatment of melanoma.

Adhesiveness of opportunistic Staphylococcus aureus to materials used in dental office: Invitro study.

Staphylococcus aureus (S.aureus) is one of several opportunistic microbial pathogens associated with many healthcare problems. In the present study, S. aureus was assessed for its biofilm-forming ability on materials routinely used in dental offices, including stainless steel (SS), polyethylene (PE), and polyvinyl chloride (PVC). Materials that were tested were characterized for roughness (Ra) and surface free energy (SFE). The adhesion forces exerted by S. aureus to each substratum were investigated using atomic force microscopy (AFM), and biofilm formation was quantitatively assessed by crystal violet staining assay. AFM measurements demonstrated that the strongest adhesion forces (20nN) were exerted on the PE surfaces (P<0.05) and depended more on Ra. In addition, the results of biofilm formation capability indicated that S. aureus exhibited more affinity to SS materials when compared to the other materials (P<0.05). This ability of biofilm formation seems to be more correlated to SFE (R=0.65). Hence, control of the surface properties of materials used in dental practices is of crucial importance for preventing biofilm formation on dental materials to be used for patients' dental care.

Photoinactivation of single and mixed biofilms of Candida albicans and non-albicans Candida species using Photodithazine®

This study evaluated the effectiveness of antimicrobial photodynamic therapy (aPDT) mediated by Photodithazine® (PDZ) formulated in hydrogel, in the inactivation of mono and duo-species biofilms of Candida albicans, Candida glabrata and Candida tropicalis. Standardized suspensions of each strain were prepared and after biofilm formation, mono-species were treated with 150 and 175mg/L of PDZ for 20min (pre-irradiation time), and exposed to LED light at a dose of 37.5J/cm2 (660nm). The duo-species biofilms (C. albicans+C. glabrata and C. albicans+C. tropicalis) were treated with 150mg/L of PDZ and light. Additional samples were treated with PDZ or light only, and the control did not receive any treatment. Next, microbiological evaluation was performed by spreading the cells on Sabouraud Dextrose Agar and CHROMagar Candida for colony forming units (CFU/mL). Moreover, the total biomass of biofilm was verified using the crystal violet staining assay (CV). The data were submitted to ANOVA and Tukey post-hoc (α=0.05). The use of PDZ 150mg/L promoted a reduction of 1.0, 1.2, 1.5 log10 in the viability of C. glabrata, C. albicans and C. tropicalis, respectively. The same concentration reduced in 1.0 log10 the viability of each species grown as duo-species biofilms. The crystal violet assay showed that the use of 150mg/L reduced 24.4%, 39.2% and 43.7% of the total biomass of C. albicans, C. tropicalis and C. glabrata, respectively. aPDT did not reduce the total biomass to the duo-species biofilms. Thus, PDZ-mediated aPDT was more effective in the inactivation of mono-species biofilms of Candida spp. compared with duo-species biofilm.

Melatonin Receptor Agonists as the "Perioceutics" Agents for Periodontal Disease through Modulation of Porphyromonas gingivalis Virulence and Inflammatory Response.

Aim“Perioceutics” including antimicrobial therapy and host modulatory therapy has emerged as a vital adjunctive treatment of periodontal disease. Melatonin level was significantly reduced in patients with periodontal diseases suggesting melatonin could be applied as a potential “perioceutics” treatment of periodontal diseases. This study aims to investigate the effects of melatonin receptor agonists (melatonin and ramelteon) on Porphyromonas gingivalis virulence and Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation.MethodsEffects of melatonin receptor agonists on Porphyromonas gingivalis planktonic cultures were determined by microplate dilution assays. Formation, reduction, and viability of Porphyromonas gingivalis biofilms were detected by crystal violet staining and MTT assays, respectively. Meanwhile, biofilms formation was also observed by confocal laser scanning microscopy (CLSM). The effects on gingipains and hemolytic activities of Porphyromonas gingivalis were evaluated using chromogenic peptides and sheep erythrocytes. The mRNA expression of virulence and iron/heme utilization was assessed using RT-PCR. In addition, cell viability of melatonin receptor agonists on human gingival fibroblasts (HGFs) was evaluated by MTT assays. After pretreatment of melatonin receptor agonists, HGFs were stimulated with Pg-LPS and then release of cytokines (IL-6 and lL-8) was measured by enzyme-linked immunosorbent assay (ELISA).ResultsMelatonin and ramelteon did exhibit antimicrobial effects against planktonic culture. Importantly, they inhibited biofilm formation, reduced the established biofilms, and decreased biofilm viability of Porphyromonas gingivalis. Furthermore, they at sub-minimum inhibitory concentration (sub-MIC) concentrations markedly inhibited the proteinase activities of gingipains and hemolysis in a dose-dependent manner. They at sub-MIC concentrations significantly inhibited the mRNA expression of virulence factors (kgp, rgpA, rgpB, hagA, and ragA), while increasing the mRNA expression of ferritin (ftn) or hemolysin (hem). They did not show obvious cytotoxicity toward HGFs. They inhibited Pg-LPS-induced IL-6 and IL-8 secretion, which was reversed by luzindole, the melatonin receptor antagonist.ConclusionMelatonin receptor agonists can inhibit planktonic and biofilm growth of Porphyromonas gingivalis by affecting the virulent properties, as well as Pg-LPS-induced inflammatory response. Our study provides new evidence that melatonin receptor agonists might be useful as novel “perioceutics” agents to prevent and treat Porphyromonas gingivalis-associated periodontal diseases.

Comparative effect of a stannous fluoride toothpaste and a sodium fluoride toothpaste on a multispecies biofilm

ObjectivesThis paper aimed to compare the mode of action of a stannous fluoride-containing toothpaste with a conventional sodium fluoride-containing toothpaste on anti-biofilm properties. MethodsA three-species biofilm model that consists of Streptococcus mutans, Streptococcus sanguinis and Porphyromonas gingivalis was established to compare the anti-biofilm properties of a stannous fluoride-containing toothpaste (CPH), a conventional sodium fluoride-containing toothpaste (CCP) and a negative control (PBS). The 48h biofilms were subjected to two-minute episodes of treatment with test agents twice a day for 5 consecutive days. Crystal violet staining and XTT assays were used to evaluate the biomass and viability of the treated biofilm. Live/dead staining and bacteria/extracellular polysaccharides (EPS) double-staining were used to visualize the biofilm structure and to quantify microbial/extracellular components of the treated biofilms. Species-specific fluorescent in situ hybridization and quantitative polymerase chain reaction (qPCR) were used to analyze microbial composition of the biofilms after treatment. ResultsThe biomass and viability of the biofilms were significantly reduced after CPH toothpaste treatment. The inhibitory effect was further confirmed by the live/dead staining. The EPS amounts of the three-species biofilm were significantly reduced by CCP and CPH treatments, and CPH toothpaste demonstrated significant inhibition on EPS production. More importantly, CPH toothpaste significantly suppressed S. mutans and P. gingvalis, and enriched S. sanguinis in the three-species biofilm. In all experiments CPH had a significantly greater effect than CCP (p<0.05) and CCP had a greater effect than PBS (p<0.05). ConclusionsStannous fluoride-containing toothpaste not only showed better inhibitory effect against oral microbial biofilm, but was also able to modulate microbial composition within multi-species biofilm compared with conventional sodium fluoride-containing toothpaste.

The impacts of a fliD mutation on the biofilm formation of Helicobacter pylori

ObjectiveTo investigate the impact of the fliD gene on the biofilm formation of Helicobacter pylori (H. pylori). MethodsH. pylori fliD mutant was constructed using inverse PCR mutagenesis. The mobility of the bacteria and its adhesion ability to human epithelial cells were assessed using a motility assay and a fluorescein isothiocyanate staining adhesion assay, respectively. The formation of biofilm was evaluated using a pellicle assay and a crystal violet staining assay. The cyto-architecture of the biofilm was documented with scanning electron microscopy. ResultsIt was found that there was no significant difference in the levels of bacterial adhesion and the biofilm formation between the wild-type ATCC 43504 and the fliD mutant. Apart from a poor motility, the fliD mutant had a slightly delayed formation of its biofilm and an incomplete cyto-architecture of its biofilm. The bacterial cells residing in the biofilm of the fliD mutant showed a loose accumulation with less apparent cross-linking fibrils. Most of the mutant cells had truncated flagella. ConclusionsThis study provides the preliminary evidences that fliD potentially regulates biofilm formation and is required for the motility of H. pylori. Further studies need to be performed in order to develop fliD as a novel target for vaccine or antimicrobial agent in future.

Candida virulence and ethanol‐derived acetaldehyde production in oral cancer and non‐cancer subjects

To compare biofilm-forming ability, hydrolytic enzymes and ethanol-derived acetaldehyde production of oral Candida isolated from the patients with oral cancer and matched non-oral cancer. Fungal biofilms were grown in RPMI-1640 medium, and biofilm mass and biofilm activity were assessed using crystal violet staining and XTT salt reduction assays, respectively. Phospholipase, proteinase, and esterase production were measured using agar plate method, while fungal acetaldehyde production was assessed via gas chromatography. Candida isolated from patients with oral cancer demonstrated significantly higher biofilm mass (P=0.031), biofilm metabolic activity (P<0.001), phospholipase (P=0.002), and proteinase (P=0.0159) activity than isolates from patients with non-oral cancer. High ethanol-derived acetaldehyde-producing Candida were more prevalent in patients with oral cancer than non-oral cancer (P=0.01). In univariate regression analysis, high biofilm mass (P=0.03) and biofilm metabolic activity (P<0.001), high phospholipase (P=0.003), and acetaldehyde production ability (0.01) were significant risk factors for oral cancer; while in the multivariate regression analysis, high biofilm activity (0.01) and phospholipase (P=0.01) were significantly positive influencing factors on oral cancer. These data suggest a significant positive association between the ability of Candida isolates to form biofilms, to produce hydrolytic enzymes, and to metabolize alcohol to acetaldehyde with their ability to promote oral cancer development.

Abstract 1191: Anti-tumor effect of selective progesterone receptor modulator (ulipristal acetate) on endometrial cancer cell lines

Abstract Background: Endometrial cancer is the most common malignancy of the female reproductive tract and the third most common cause of death from women's cancer. Risk factors of endometrial cancer include high levels of estrogen, obesity, diabetes mellitus, breast cancer, long term use of tamoxifen, late menopause, high blood pressure, and increasing age. Although the exact mechanisms in endometrial carcinogenesis due to chronic exposure are unclear, it is though that the pro-proliferative and DNA-damaging effects of estrogen and its metabolites, related with and insufficient counterbalance by progesterone, promote the hyper-proliferation and transformation of cells. Selective progesterone receptor modulator (SPRM) is an agent that acts on the progesterone receptor. Ulipristal acetate (UA) is one of SPRM and other SPRM, such as Mifepristone, showed inhibitory effect on various endometrial cancer cell lines. UA has been available as an emergency contraception and a treatment for uterine leiomyoma. The effect of UA on leiomyoma is decreasing neovascularization, proliferation, and viability. Objective: This study was undertaken to investigate antitumor effect of UA and to explore the effect of combination treatment with chemotherapy drug in endometrial cancer. Method: Inhibitory concentration (IC), proliferation assay, and migration assay were performed using Ishikawa, HEC-1-A, HEC-1-B, and/or patient-derived primary cancer cells (PCC). Different concentration of UA were treated in endometrial cancer cell lines and PCCs for the each assay. The CellTiter-Glo assay were performed to investigate IC50 in cell lines and PCCs. Crystal violet staining and wound healing assay were performed to examine cell proliferation and migration. Results: UA inhibited cell viability of endometrial cancer cell lines and PCCs at high concentration, most abviously 10uM in dose-dependent manner. In combination treatment assay with paclitaxel, UA showed synergistic anti-tumor effect with low-dose of paclitaxel on cell lines and PCCs. Conclusions: We showed that combination treatment of UA and paclitaxel effectively than single treatment by low dosage. In summary, we are actively exploring new effective applicable drugs for endometrial cancer, and our data suggest that UA may have therapeutic value with chemo-combination treatment of patients with endometrial cancer. Citation Format: Ha-Young Lee, A Ra Ko, Dong-Woo Kang, Yu-Seon Kim, Su-Min Kim, Tae-Wook Kang, Shin-Wha Lee, Yong-Man Kim. Anti-tumor effect of selective progesterone receptor modulator (ulipristal acetate) on endometrial cancer cell lines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1191.

Abstract 653: Identification of metastasis promoting genes using the PiggyBac insertional mutagenesis system

Abstract The Myc oncogene is overexpressed in approximately 30% of human breast cancers. Mice carrying the mammary tumor virus LTR/c-myc (MMTV-c-Myc) develop mammary tumors, but display a relatively low rate of metastases to the lung. However, not all cells that express the transgene develop neoplasms indicating that Myc-induced tumorigenesis requires additional cooperating events for full transformation. To identify genes that cooperate with Myc-induced tumorigenesis leading to the acceleration of tumor progression or an increase in metastases in MMTV-Myc transgenic mice, we have employed the PiggyBac (PB) transposon system. The PiggyBac system used in our studies was (developed by Rad et al, Science, 2010) is composed of two elements, the ATP-1 PiggyBac transposon and transposase. ATP-1 transposons are mobile DNA elements that can randomly integrate throughout the genome in the presence of transposase resulting in the activation or loss of gene function. The insertion sites can be identified through sequencing. It has been used successfully for genomic modification of cells in vivo leading to cancer gene discovery. In order to better adapt the PB system for studing mammary gland biology, we have designed a system to express a hyperactive transposase and luciferase specifically in the mammary gland using the MMTV LTR (MMTV-hyTPase-luc). The efficiency of MMTV-hyTPase-luc expression was first examined in vitro by transfection with an ATP-1 containing plasmid using the HC11 mouse mammary epithelial cell line. Selection for integration of ATP1 in the cells using puromycin selection and crystal violet staining, RT-QPCR and luciferase assays confirmed that MMTV-hyTPase-luc led to efficient integration of ATP-1 into the HC11 cells. HC11 cell proliferation further increased in the presence of dexamethasone, a hormone that stimulates MMTV promotor function. The MMTV-HyPB-Luc construct was subsequently used to generate transgenic mice and multiple founder lines are being analyzed for mammary specific transposase expression. The best expressing line will be crossed with MMTV-cMyc mice and mice carrying multiple copies of the ATP1 transposon. Transposon integration sites will be determined from tumors or metastases in mice with accelerated tumor development and/or increased metastases compared to controls. Further molecular characterization and validation of candidate genes will identify novel genes that cooperate with Myc to augment tumorigenesis and metastases. Citation Format: Qiu N. Tinghu, Laura Vera Ramirez, Roland Rad, Jeffrey E. Green. Identification of metastasis promoting genes using the PiggyBac insertional mutagenesis system. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 653.

Salmonella enterica isolates from layer farm environments are able to form biofilm on eggshell surfaces

This study examined the eggshell biofilm forming ability of Salmonella enterica isolates recovered from egg farms. Multicellular behaviour and biofilm production were examined at 22 and 37°C by Congo red morphology and the crystal violet staining assay. The results indicated that the biofilm forming behaviour of Salmonella isolates was dependent on temperature and associated with serovars. Significantly greater biofilm production was observed at 22°C compared with 37°C. The number of viable biofilm cells attached to eggshells after incubation for 48 h at 22°C was significantly influenced by serovar. Scanning electron microscopic examination revealed firm attachment of bacterial cells to the eggshell surface. The relative expression of csgD and adrA gene was significantly higher in eggshell biofilm cells of S. Mbandaka and S. Oranienburg. These findings demonstrate that Salmonella isolates are capable of forming biofilm on the eggshell surface and that this behaviour is influenced by temperature and serovar.

Photodynamic inactivation of a multispecies biofilm using curcumin and LED light.

This study evaluated the potential of curcumin-mediated antimicrobial photodynamic inactivation (API) on multispecies biofilms of Candida albicans, Candida glabrata, and Streptococcus mutans of different ages. Acrylic samples (n = 480) were made with standardized rough surfaces and incubated with bacteria and yeast for 24 or 48h. API was performed with curcumin (80, 100, 120μM) and LED light. Additional acrylic samples were treated with curcumin or LED light only. Positive control samples received neither light nor curcumin. After API, colony counts were quantified (CFU/mL), cell metabolism was determined by means of XTT assay, and the total biofilm biomass was evaluated using Crystal Violet (CV) staining assay and images were obtained by confocal laser scanning microscopy (CLSM). The data were analyzed by nonparametric two-way ANOVA and post hoc Tukey tests (α < 0.05). For 24-h biofilm, API resulted in statistically significant difference (ρ < 0.001) of viability of C. albicans compared with control (P-L-) for all Cur concentrations. For 48-h biofilm, API resulted in statistically significant difference (ρ < 0.001) compared with control only when Cur at 120μM was used. API promoted statistically significant difference (ρ ≤ 0.001) in the viability of S. mutans and C. glabrata for all Cur concentrations in the two biofilm ages. In addition, API produced a statistically significant difference (ρ < 0.001) of metabolic activity and of total biomass (ρ < 0.001) of multispecies biofilms compared with control for all Cur concentrations. It can be concluded that both 24- and 48-h biofilms were susceptible to API mediated by Cur; however, 24-h biofilm was more sensitive than the 48-h biofilm.

Effect of denture-coating composite on Candida albicans biofilm and surface degradation after disinfection protocol

Denture stomatitis is the most common pathology affecting denture wearers and its main cause is colonisation of dentures with Candida albicans. This study investigated the effectiveness of two commercial composite surface sealants (Biscover(®) LV and Surface Coat(®)) to reduce C. albicans biofilm colonisation on denture resin, as well as their surface integrity after disinfection cycles with 1% sodium hypochlorite solution. Heat-cured acrylic resin specimens were manufactured (10 mm × 10 mm × 1 mm). The specimen surfaces were mechanically polished to simulate rough or smooth denture surfaces. Four surface-treatment groups were tested: smooth surfaces [0.3 μm of mean roughness (Ra)]; rough surfaces (3 μm of Ra); rough surfaces treated with Biscover(®) LV; and rough surfaces treated with Surface Coat(®). Specimens of each group were randomly divided to undergo immersion in distilled water or 1% sodium hypochlorite for 30 or 90 cycles each. Specimens of all groups in each immersion solution were tested using a crystal violet (CV) staining assay for biofilm quantification and by scanning electron microscopy for visual analyses of surface integrity and biofilm structure. CV assay data were analysed using one-way analysis of variance (ANOVA) followed by Tukey's multiple comparison test (P < 0.05). The effectiveness and surface integrity of Biscover(®) LV-treated surfaces were similar to those of smooth surfaces, whereas Surface Coat(®) -treated surfaces presented a similar performance to rough surfaces in all solutions and cycles. These results suggest the possibility of clinical use of Biscover(®) LV for denture coating on surfaces in which mechanical polish is not indicated, such as the fitting surface.

Oridonin inhibits the proliferation of human colon cancer cells by upregulating BMP7 to activate p38 MAPK.

Oridonin (ORI), a diterpenoid purified from Rabdosia rubescens, has been reported as a promising chemotherapy drug for colon cancer treatment; yet, the precise mechanisms underlying this anticancer activity remain unclear. In the present study, we investigated the anticancer effect of ORI in HCT116 cells, and dissected the possible molecular mechanisms underlying this activity. With crystal violet staining, flow cytometry and western blot assay, we found that ORI effectively inhibited the proliferation and induced the apoptosis of HCT116 cells. Further analysis of the results indicated that BMP7 was greatly upregulated by ORI in the HCT116 cells, but its endogenous expression in FHC cells was apparently lower than that in the colon cancer cell lines. Exogenous expression of BMP7 inhibited the proliferation of the HCT116 cells, and substantially potentiated the anticancer effect of ORI. However, the specific antibody of BMP7 nearly abolished this anticancer activity of ORI in the HCT116 cells. Meanwhile, ORI exerted no significant effect on the level of phosphorylated Smad1/5/8 or total p38 MAPK, but greatly increased the level of phosphorylated p38 MAPK in the HCT116 cells. A p38 MAPK-specific inhibitor partly reversed the antiproliferative effect of BMP7 in the HCT116 cells, but prominently promoted the effect of the BMP7 antibody on proliferation. Exogenous expression of BMP7 increased the ORI-induced phosphorylation of p38 MAPK, while the BMP7 antibody almost abolished the ORI-elevated p38 MAPK phosphorylation. Our findings suggest that ORI may be an efficacious drug for colon cancer treatment. This anticancer activity of ORI may be mediated by upregulating BMP7 at least to increase the activation of p38 MAPK.

Antibacterial and antibiofilm activities of Laurus nobilis L. essential oil against Staphylococcus aureus strains associated with oral infections

BackgroundLaurus nobilis L. is an aromatic herb with relevant medicinal properties due to its important chemical composition and its potential therapeutic effects. In this study, we investigate the chemical composition, the antibacterial and the antibiofilms activities of Tunisian L. nobilis L. essential oils against clinical Staphylococcus aureus strains. MethodsThe chemical composition of L. nobilis L. essential oils was analysed by Gas Chromatography-Mass Spectrometry (GC–MS). The antibacterial activity of L. nobilis L. essential oils was evaluated in vitro against oral S. aureus (n=21) strains using broth microdilution method. The antibiofilm activity was assessed via Crystal Violet staining and MTT assays. ResultsOur results revealed that GC–MS assay exhibited 1.8-Cineole, methyl eugenol and α-terpinyl acetate as the major compounds in the essential oils. Moreover, the essential oil from Sousse exhibited the best bactericidal activity (MICs values ranged from 3.91 to 15.62mgm−1). Furthermore, this oil showed a strong biofilm inhibition effect above 70%, from a low sub-inhibitory concentration (1/16×MIC). MTT assay revealed that both essential oils displayed an excellent antibiofilm activity with eradication percentages ranging from 79.6±2.27 to 95.2±0.56. ConclusionOur finding demonstrated that L. nobilis L. essential oils are able to inhibit oral S. aureus strains with important antibiofilm efficacy. It could have a promising role in the prevention of oral diseases.

Strong poly(ethylene oxide) based gel adhesives via oxime cross-linking

There is a demand for materials to replace or augment the use of sutures and staples in surgical procedures. Currently available commercial surgical adhesives provide either high bond strength with biological toxicity or polymer and protein-based products that are biologically acceptable (though with potential sensitizing potential) but have much reduced bond strength. It is desirable to provide novel biocompatible and biodegradable surgical adhesives/sealants capable of high strength with minimal immune or inflammatory response. In this work, we report the end group derivatization of 8-arm star PEOs with aldehyde and amine end groups. Gels were prepared employing the Schiff-base chemistry between the aldehydes and the amines. Gel setting times, swelling behavior and rheological characterization were carried out for these gels. The mechanical-viscoelastic properties were found to be directly proportional to the crosslinking density of the gels, the 10K PEO gel was stiffer in comparison to the 20K PEO gel. The adhesive properties of these gels were tested using porcine skin and showed excellent adhesion properties. Cytotoxicity studies were carried out for the individual gel components using two different methods: (a) Crystal Violet Staining assay (CVS assay) and (b) impedance and cell index measurement by the xCELLigence system at concentrations >5%. Gels prepared by mixing 20% w/w solutions were also tested for cytotoxicity. The results revealed that the individual gel components as well as the prepared gels and their leachables were non-cytotoxic at these concentrations. Statement of SignificanceThis work presents a new type of glue that is aimed at surgery applications using a water soluble star shaped polymer. It show excellent adhesion to skin and is tough and easy to use. We show that it is very biocompatible based on tests on live human cells, and could therefore in principle be used for internal surgery. Comparison with other reported and commercial glues shows that it is stronger than most, and does not swell in water to the same degree as many other water based bioadhesives.