A Stream X-Machine Tool for Modelling and Generating Test Cases for Chronic Diseases Based on State-Counting Approach

Programming and Computer Software - In the biomedical domain, diagrammatical models have been extensively used to describe and understand the behaviour of biological organisms (biological agents)...     

Metabolites from an Antarctic sponge-associated bacterium, Pseudomonas aeruginosa

In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms. A series of diketopiperazines (1-6) including a new natural product (6) and two known phenazine alkaloid antibiotics (7 and 8) were isolated from the culture broth of this bacterium.     

Development of white mustard (Sinapis alba L.) essential oil,a food preservative

White mustard essential oil (WMEO) has antimicrobial properties due to the presence of p-hydroxybenzyl isothiocyanate (p-HBITC). WMEO containing about 8% p-HBITC was made on a commercial scale as it is not commercially available. When characterised by HPLC/high resolution mass spectrometry, the triacylglycerols of WMEO and white mustard oil were found to be identical. Non-triacylglycerol components of WMEO could be directly traced back to those occurring naturally in the Brassicaceae family and enhanced by the presence of p-HBITC. New HPLC methods for analysing p-HBITC and its hydrolytic products showed that p-HBITC hydrolysis was slower under acidic conditions. The non-sulphur containing hydrolytic products p-hydroxybenzyl alcohol (p-HBA), p-hydroxybenzyl cyanide (p-HBCN) and p-cresol, were also quantitatively analysed. Commercial production of WMEO containing p-HBITC is feasible and will also result in defatted and deheated mustard flour with about 44% protein as a byproduct.     

Homarine as a feeding deterrent in common shallow-water antarctic lamellarian gastropodMarseniopsis mollis: A rare example of chemical defense in a marine prosobranch

The common bright yellow antarctic lamellarian gastropodMarseniopsis mollis was examined for the presence of defensive chemistry. Proton nuclear magnetic resonance (NMR) spectroscopy indicated that a major component of ethanolic extracts purified by reversed-phase column chromatography was homarine. Further high-performance liquid chromatography (HPLC) analysis of the mantle, foot, and viscera verified the presence of homarine in all body tissues at concentrations ranging from 6 to 24 mg/g dry tissue. A conspicuous macroinvertebrate predator of the shallow antarctic benthos, the sea starOdontaster validus, always rejected live individuals ofM. mollis, while readily feeding on pieces of fish tail muscle. Filter paper disks treated with shrimp elicited a broad range of feeding behaviors in the sea starO. validus (movement of disc to mouth, extrusion of cardiac stomach, humped feeding posture). Shrimp disks treated with homarine (0.4 and 4 mg/disk) were rejected byO. validus significantly more frequently than control disks treated with solvent carrier and shrimp or shrimp alone. The highest concentration of homarine tested not only caused feeding deterrence, but in several sea stars a flight response was noted. Homarine was not detected in the tunic of the antarctic ascidianCnemidocarpa verrucosa, a presumed primary prey ofM. mollis. Nonetheless, crude extracts of the epizooites that foul the tunic (primarily the bryozoans and hydroids) contain homarine, suggestingM. mollis may ingest and derive its chemistry from these organisms. This appears to be only the third example of chemical defense in a member of the Order Mesogastropoda. As the vestigial internalized shell ofM. mollis is considered a primitive condition, the findings of this study lend support to the hypothesis that chemical defense evolved prior to shell loss in shell-less gastropods.