Linawati Hardjito

The influence of environmental conditions on the production of pigment bySerratia marcescens

Serratia marcescens biovar A2/A6, isolated from an Indonesian freshwater source, was identified based on extensive morphological, biochemical and genetic characterization. Formation of pigment was found to be strongly influenced by environmental conditions. Placket-Burman design was used to analyze the effect of carbon and nitrogen sources. Based on results of physiological and biochemical studies, the optimum conditions for growth and pigment formation were incubation 30°C in a neutral to slightly alkaline medium containing lactic acid and beef extract.

Nutritional Composition and Topoisomerase Inhibitor Activity of Ethnomedicinal Marine Mollusk Nerita albicilla

DNA topoisomerases (topo) I and II are molecular targets of several potent anticancer agents. Thus, inhibitors of these enzymes are potential candidates for anticancer development. Traditionally, Nerita albicilla had been used in Kei Island, Southern Maluku, Indonesia to treat liver disease including cancer. The paper reports on the chemical composition of Nerita albicilla and its topo I inhibitor of hexane, ethyl acetate and methanol extracts. Topoisomerase-I inhibitor activity was determined using the method reported by TopoGEN. The proximate analysis described that Nerita albicilla dried powder contained 12.45% ± 0.05% moisture; 9.17% ± 0.03% ash; 62.05% ± 0.10% protein; 5.58% ± 0.08% fat; 6.60% ± 0.02% crude fiber and 4.15% ± 0.24% carbohydrate (by difference). Furthermore, the protein consisted of 11 essential amino acids and six non-essential amino acids. It contained significant amount of branched-chain amino acids (BCAA) valine, leucine, isoleucine (a total of 187.8 mg g -1 protein) and lower content of aromatic amino acids phenylalanine, tyrosine and histidine (a total of 111.26 mg g -1 protein). The protein score was 92.2. The yield of hexane, ethyl acetate and methanol extracts of Nerita albicilla were 2.05% ± 0.05%, 1.56% ± 0.06% and 6.99% ± 0.14%, respectively. All extracts showed topoisomerase-I inhibitor activities. Minimum inhibitory concentration (MIC) of methanol extract was 2.50 µg mL -1 . Chemical screening of the extracts showed that they contained steroidal and alkaloid compounds. The investigation revealed that Nerita albicilla contains active compounds that could be potential for nutraceutical or pharmaceutical development.