ABSTRACT
The development and world-wide spread of multidrug-resistant (MDR) bacteria have a high concern in the medicine, especially the extended-spectrum of beta-lactamase (ESBL) producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA). There are currently very limited effective antibiotics to treat infections caused by MDR bacteria. Peat-soil is a unique environment in which bacteria have to compete each other to survive, for instance, by producing antimicrobial substances. This study aimed to isolate bacteria from peat soils from South Kalimantan Indonesia, which capable of inhibiting the growth of Gram-positive and Gram-negative bacteria. Isolates from peat soil were grown and identified phenotypically. The cell-free supernatant was obtained from broth culture by centrifugation and was tested by agar well-diffusion technique against non ESBL-producing E. coli ATCC 25922, ESBL-producing E. coli ATCC 35218, methicillin susceptible Staphylococcus aureus (MSSA) ATCC 29,213 and MRSA ATCC 43300. Putative antimicrobial compounds were separated using SDS-PAGE electrophoresis and purified using electroelution method. Antimicrobial properties of the purified compounds were confirmed by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In total 28 isolated colonies were recovered; three (25PS, 26PS, and 27PS) isolates produced proteins with strong antimicrobial activities against both reference strains. The substance of proteins from three isolates exerted strong antimicrobial activity against ESBL-producing E. coli ATCC 35,218 (MIC = 2,80 µg/mL (25PS), 3,76 µg/mL (26PS), and 2,41 µg/mL (27PS), and MRSA ATCC 43,300 (MIC = 4,20 µg/mL (25PS), 5,65 µg/mL (26PS), and 3,62 µg/mL (27PS), and also had the ability bactericidal properties against the reference strains. There were isolates from Indonesian peat which were potentials sources of new antimicrobials.
ABSTRACT
Objective To prove the molecular mechanisms of Mahkota Dewa (Phaleria macrocarpa) in suppressing proliferation of human retinoblastoma cells through suppression of cell cycle's gene-regulators expression. Methods In this study, the molecular mechanism of anti-tumor effect of fractioned extract of Phaleria macrocarpa (DLBS1425) in human retinoblastoma cells Y-79 was investigated by measuring the tumor cells viability, the assessment of population profiles of tumor cells in the cell cycle, and the mRNA concentration of p16, p21, p53, cyclin D, cyclin E, and E2F. Results DLBS1425 showed an inhibition effects towards proliferation of Y-79 cell line. Inhibition of proliferation was shown by suppression of cell cycle progression. DLBS1425 downregulated cyclin E, a G1 phase regulator gene of cell cycle, in dose-dependent manner without affecting p53–p21 pathway. In the other word, DLBS1425 inhibits cell proliferation through suppression of cyclin E independently towards conventional proliferation pathway. Conclusions Our results suggest that DLBS1425 is a potential anticancer agent which targets genes involved in cell proliferation in human retinoblastoma cells which make it pharmacologically ideal for the prevention and/or treatment of retinoblastoma cancer.
