BUMC Annual Report

Annual report of the Boston University Medical Center

Inhibition of Biofilm Formation, Quorum Sensing and Infection in Pseudomonas aeruginosa by Natural Products-Inspired Organosulfur Compounds

Using a microplate-based screening assay, the effects on Pseudomonas aeruginosa PAO1 biofilm formation of several S-substituted cysteine sulfoxides and their corresponding disulfide derivatives were evaluated. From our library of compounds, S-phenyl-L-cysteine sulfoxide and its breakdown product, diphenyl disulfide, significantly reduced the amount of biofilm formation by P. aeruginosa at levels equivalent to the active concentration of 4-nitropyridine-N-oxide (NPO) (1 mM). Unlike NPO, which is an established inhibitor of bacterial biofilms, our active compounds did not reduce planktonic cell growth and only affected biofilm formation. When used in a Drosophila-based infection model, both S-phenyl-L-cysteine sulfoxide and diphenyl disulfide significantly reduced the P. aeruginosa recovered 18 h post infection (relative to the control), and were non-lethal to the fly hosts. The possibility that the observed biofilm inhibitory effects were related to quorum sensing inhibition (QSI) was investigated using Escherichia coli-based reporters expressing P. aeruginosa lasR or rhIR response proteins, as well as an endogenous P. aeruginosa reporter from the lasI/lasR QS system. Inhibition of quorum sensing by S-phenyl-L-cysteine sulfoxide was observed in all of the reporter systems tested, whereas diphenyl disulfide did not exhibit QSI in either of the E. coli reporters, and showed very limited inhibition in the P. aeruginosa reporter. Since both compounds inhibit biofilm formation but do not show similar QSI activity, it is concluded that they may be functioning by different pathways. The hypothesis that biofilm inhibition by the two active compounds discovered in this work occurs through QSI is discussed

The Drosophila melanogaster host model

The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed

Adsorption of Lead(II) Ions using Coconut Fiber’s (Cocos nusifera L.) Activated by Sodium Hydroxide

The use of green coconut fiber waste to adsorb lead(II) ions has been successfully carried out. Coconut fiber was activated first using sodium hydroxide before being used as an adsorbent. The optimum time needed for green coconut fiber to adsorb lead(II) ions was 30 minutes with the percentage of ions adsorbed by 94.34%. The lead(II) adsorption kinetics on green coconut fiber model with R2 value of 0.999 and k value of 38.95 x 10-4 minutes-1. Adsorption isotherm from lead(II) on coconut fiber followed the Langmuir adsorption model with R2 value of 0.984 and adsorption capacity of 0.070 g.mg-1.</jats:p

Nutritional Status Of Infants Based On Frequency And Dietary Diversity Of Complementary Feeding

Background: In 2017, the prevalence of malnutrition in Indonesia was ranked 4­th among Southeast Asia countries. The nonoptimal complementary feeding is one of the reasons. The nonoptimal complementary feeding is associated with the prevalence of underweight and stunting in the children at the age 6-23 months. Complementary feeding pattern include frequency and dietary diversity. This study aims to investigate the relationship between complementary feeding pattern and nutritional status of infants at the age 7-12 months in the Kedungwaru Health Center, Tulungagung. Methods: This study used observational analytic and cross-sectional study design. The sample consisted of 71 mothers of the infants which were taken by total sampling. The variables of this study were complementary feeding pattern and nutritional status. This study also used a questionnaire and observation sheet. The Fisher Exact Test was used to analyse the data. Result: The results showed 88.7% of the infants have good nutritional status. There are 49.3% appropriate complementary feeding and 69% which applied various types of complementary feeding. The frequency of complementary feeding with the nutritional status of infants obtained p value 0.478 and the dietary diversity of complementary feeding with nutritional status obtained p value 0.102. Conclusions: There were no significant relation between the complementary feeding pattern and the nutritional status (weight-for-age) in infants at the age 7-12 months. Further research about other variables is needed