METHODS: Broth microdilution and semi-quantitative adherence assays were conducted to determine the anti-biofilm activity of the fungal extract. Light and scanning electron microscopy (SEM) analyses were performed to observe the effect of the fungal extract on biofilm formation by MRSA.
RESULTS: The transmission electron microscopy (TEM) microphotographs showed that the bacterial cells were severely damaged upon 24 h exposure to the extract and displayed several symptoms such as cell shrinkage and breakage. Meanwhile, results from the antibiofilm study indicated the extract attenuated the initial and preformed biofilms of MRSA by 80.82% and 61.39%, respectively. The initial biofilm was more sensitive to the extract compared to the pre-formed biofilm, as evidenced by the light microscopy and SEM observations that demonstrated more severe bacterial cell damage on the initial biofilms compared to pre-formed biofilms.
CONCLUSION: The ethyl acetate extract of L. pseudotheobromae IBRL OS-64 significantly inhibited bacterial cells growth and eliminated biofilm formation by MRSA.
Biofouling is a phenomenon that describes the fouling organisms attached to man-made surfaces immersed in water over a period of time. It has emerged as a chronic problem to the oceanic industries, especially the shipping and aquaculture fields. The metal-containing coatings that have been used for many years to prevent and destroy biofouling are damaging to the ocean and many organisms. Therefore, this calls for the critical need of natural product-based antifoulants as a substitute for its toxic counterparts. In this study, the antibacterial and antibiofilm activities of the bioactive compounds of Pseudoalteromonas sp. IBRL PD4.8 have been investigated against selected fouling bacteria. The crude extract has shown strong antibacterial activity against five fouling bacteria, with inhibition zones ranging from 9.8 to 13.7 mm and minimal inhibitory concentrations of 0.13 to 8.0 mg/ml. Meanwhile, the antibiofilm study has indicated that the extract has attenuated the initial and pre-formed biofilms of Vibrio alginolyticus FB3 by 45.37 ± 4.88% and 29.85 ± 2.56%, respectively. Moreover, micrographs from light and scanning electron microscope have revealed extensive structural damages on the treated biofilms. The active fraction was fractionated with chromatographic methods and liquid chromatography-mass spectroscopy analyses has further disclosed the presence of a polyunsaturated fatty acid 4,7,10,13-hexadecatetraenoic acid (C16H24O2). Therefore, this compound was suggested as a potential bioactive compound contributing to the antibacterial property. In conclusion, Pseudoalteromonas sp. IBRL PD4.8 is a promising source as a natural antifouling agent that can suppress the growth of five fouling bacteria and biofilms of V. alginolyticus FB3.
METHODS: Rats were assigned into six groups; two groups received 150 mg/kg or 300 mg/kg of OELE, one group received a single dose of cisplatin (6 mg/kg) IP on the first day of the experiment, two groups received a single dose of cisplatin 150 mg/kg or 300 mg/kg of OELE on the first day then starting from the fifth day for 10 consecutive days, and one group acted as a control. Results and Conclusion. The findings showed that cisplatin-induced nephrotoxicity was evidenced by a significant increase in serum creatinine blood urea nitrogen (BUN) and a significant decrease in estimated creatinine clearance and potassium level, which corresponded with the alterations in the histopathology of the renal tissue. OELE significantly ameliorated the nephrotoxic effects of cisplatin as dose-dependent.
RESULTS: The primary and secondary pectinase activity screenings by Aspergillus niger LFP-1 were performed using pectin screening agar and shake flask system, respectively. The finding revealed that the locally isolated strain is able to secrete favourable pectinase production. Before improvement, the pectinase production was 0.88 ± 0.09 U/mL. However, the improved conditions such as 6 days of the cultivation period, agitation speed of 150 rpm, inoculum size of 1 × 106 spores/mL, 2.5% (w/v) citrus pectin, and 0.4% (w/v) ammonium nitrate could significantly increase pectinase production up to 7.41 ± 0.24 U/mL, representing an 88% increase. In this study, supplementing 2.5% (w/v) citrus pectin to the culture medium as a carbon source increased enzyme production by up to 3.07 ± 0.17 U/mL. Meanwhile, 0.4% (w/v) ammonium nitrate was used as a nitrogen source yielding the highest enzyme activity with a value of 6.86 ± 0.07 U/mL.
CONCLUSION: Thus, the locally isolated fungal strain, A. niger LFP-1 has outstanding pectinase-producing capability and can be utilized for the commercial production of pectinase. The improved cultural conditions significantly increase pectinase production and shorten the incubation period from 8 days (before improvement) to 6 days (after improvement).