The antibacterial activity of 21 nm TiO2 nanoparticles (NPs) and particles modified with Garcinia zeylanica (G. zeylanica) against Methicillin resistant Staphylococcus aureus was investigated in the presence and absence of light. Surface modification of TiO2 NPs with the adsorption of G. zeylanica extract, causes to shift the absorption edge of TiO2 NPs to higher wavelength. TiO2 NPs, G. zeylanica pericarp extract showed significant bactericidal activity which was further enhanced in contact with the TiO2 modified G. zeylanica extract. The antimicrobial activity was enhanced in the presence of TiO2 NPs modified with G. zeylanica and with longer contact time.

Reactive oxygen species (ROS) are not only toxic substances inducing oxidative stress but also play a role as a second messenger in signal transduction through various receptors. Previously, B cell activation was shown to involve prolonged ROS production induced by ligation of BCR. However, the mechanisms for ROS production and ROS-mediated activation in B cells are still poorly understood. In this study, we demonstrate that BCR ligation induces biphasic ROS production in both mouse spleen B cells and the mouse B cell line BAL17; transient and modest ROS production is followed by sustained and robust ROS production at 2–6 h after BCR ligation. ROS production in the late phase but not in the early phase augments activation of signaling pathways, such as the NF-κB and PI3K pathways, and is essential for B cell proliferation. ROS production in the late phase appears to be mediated by NADPH oxidases (NOXes) because prolonged ROS production is inhibited by various NOX inhibitors, including the specific inhibitor VAS2870. BCR ligation–induced ROS production is also inhibited by CRISPR/Cas9-mediated deletion of either the Cyba gene encoding p22^phox, the regulator of NOX1-4 required for their activation, or NOX3, whereas ROS production is not affected by double deficiency of the DUOXA1 and DUOXA2 genes essential for the activation of the NOX isoforms DUOX1 and DUOX2. These results indicate that NOXes play a crucial role in sustained but not early BCR signaling and suggest an essential role of NOX-dependent sustained BCR signaling in B cell activation. Key Points BCR ligation induces ROS production in two phases. ROS production in the late phase is essential for B cell proliferation and survival. ROS production in the late phase is mediated by NADPH oxidases, especially NOX3.

Infected chronic wounds are polymicrobial in nature which include a diverse group of aerobic and anaerobic microorganisms. Majority of these communal microorganisms are difficult to grow in vitro. DNA fingerprinting methods such as polymerase chain reaction-denaturation gradient gel electrophoresis (PCR-DGGE) facilitate the microbial profiling of complex ecosystems including infected chronic wounds. Six different DNA extraction methods were compared for profiling of the microbial community associated with chronic wound infections using PCR-DGGE. Tissue debris obtained from chronic wound ulcers of ten patients were used for DNA extraction. Total nucleic acid was extracted from each specimen using six DNA extraction methods. The yield, purity and quality of DNA was measured and used for PCR amplification targeting V2–V3 region of eubacterial 16S rRNA gene. QIAGEN DNeasy Blood and Tissue Kit (K method) produced good quality genomic DNA compared to the other five DNA extraction methods and gave a broad diversity of bacterial communities in chronic wounds. Among the five conventional methods, bead beater/phenol–chloroform based DNA extraction method with STES buffer (BP1 method) gave a yield of DNA with a high purity and resulted in a higher DGGE band diversity. Although DNA extraction using heat and NaOH had the lowest purity, DGGE revealed a higher bacterial diversity. The findings suggest that the quality and the yield of genomic DNA are influenced by the DNA extraction protocol, thus a method should be carefully selected in profiling a complex microbial community.

Background. The pro- and anti-inflammatory cytokines play an important role in the immune response againstH. pyloriinfection. The proinflammatory cytokines of Th17 cells have been suggested to play a major role inH. pyloriinfection and resulting gastric inflammation.Objective. The objective of this study was to compare the expression of selected inflammatory cytokines (IL-10, IL-17, IL-21, IL-23, and TNF-α) inH. pylori-infected patients and healthy controls and to understand their association withH. pyloriinfection and disease severity.Results. The expression levels of IL-17 and IL-23 were significantly higher inH. pylori-infected patients. The expression of IL-21 was also higher inH. pylori-positive patients but there was no significant association with infection. IL-17 expression showed a significant increase with the severity of chronic gastritis.Conclusion. The proinflammatory cytokine, IL-17, shows a significant association withH. pyloriinfection and disease severity in a Sri Lankan dyspeptic patient population.

Nitrocellulose with silver nanoparticle (AgNP/NC) composite was prepared in situ using Ag(CH₃CO₂) and nitrocellulose without any reducing agent. The composite materials synthesized were spray coated onto glass substrates to obtain thin films. The AgNPs/NC composites were characterized by ultraviolet‐visible, Fourier transform infrared, X‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The antimicrobial activity of AgNPs/NC composite was investigated by tube method and time‐kill kinetic studies against three microbial species, including Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), and Candida albicans (ATCC 10231). The antibiofilm activities were qualitatively determined against all three organisms. Prepared AgNPs/NC films exhibited good antimicrobial activity and significant inhibition of biofilm development against all three microbial species. The effective dispersion of AgNPs/NC in biofilm was responsible for the significant antibiofilm activity of the prepared material. The reported AgNPs/NC composite can be used as coating additive in bacteriocidal paint which can be applied onto surfaces such as in healthcare environments.

Background: Superficial fungal foot infection (SFFI) in diabetic patients increases the risk of developing diabetic foot syndrome. Sixteen percent of urban population is suffering from diabetes in Sri Lanka. As the diabetes patients are more prone to get fungal foot infections, early intervention is advisable owing to the progressive nature of the infection. There is no data on the prevalence of SFFIs in diabetic patients in Sri Lanka. Objective: To determine the etiological agents causing SFFI in patients with type 2 diabetes. Materials and Methods : Three hundred eighty five diabetic patients were included. Nail clippings and swabs were collected from the infected sites using the standard protocol. Laboratory identification was done and pathogens were identified to the species level by morpho physiological methods. Results: Clinically 295 patients showed SFFI, of which 255 (86%) were mycologically confirmed for infection. Out of 236 direct microscopy (KOH) positives, 227 (96%) were culture positive. Two hundred and fifty one patients (98%) with SFFI had diabetes for more than 10 years. Of the patients with SFFIs 92% had >100 mg/dl FBS and 81% had >140 mg/dl PPBS levels and 80% had both elevated FBS and PPBS. Non-dermatophyte fungal species were the commonest pathogens followed by yeast and dermatophytes. Conclusion: Aspergillus niger was the commonest pathogen followed by Candida albicans. SFFIs were seen significantly with the increasing age, gender, duration of diabetes and with less controlled glycaemic level.