Three bacterial strains of marine origin were isolated during a screening for biosurfactants among n-alkane degrading microorganisms. One strain-identified as Alcaligenes sp. MM1-produced a novel glucose lipid. In the case of Arthrobacter sp. EK 1 the well-known trehalose tetraester was found as major component. From another pure culture classified as Arthrobacter sp. SI 1, extracellular emulsi...

The defensive secretion of Parectatosoma mocquerysi, a walkingstick insect from Madagascar, was determined to contain glucose, water, and a new monoterpene, parectadial, (4S)-(3-oxoprop-1-en-2-yl)cyclohex-1-enecarbaldehyde. Here, we describe the elucidation of parectadial's molecular structure and absolute configuration via microsample NMR technology, GC-MS, CD, chiral GC-FID, and synthesis fro...

The importance of juice beverages in daily food habits makes juice authentication an important issue, for example, to avoid fraudulent practices. A successful classification model should address two important cornerstones of the quality control of juicebased beverages: to monitor the amount of juice and to monitor the amount (and nature) of other substances added to the beverages. Particularly,...

Eight synthetic and nine biogenetic surfactants were tested on their toxicity. Because of their possible application as oil dispersants against oil slicks on sea, the test organisms used were marine microorganisms (mixed and pure cultures of bacteria, microalgae, and protozoa). Bacterial growth was hardly effected or stimulated, whilst that of algae and flagellates was reduced. All substances t...

The CALPHAD (CALculation of PHAse Diagrams) method provides a powerful tool for the calculation of phase diagrams. It is based on thermodynamic databases gathering information on the relative stabilities of pure substances and mixing properties of alloys. We have added a size dependent contribution to an existing CALPHAD description of the Au-Ge bulk system. The parameters are optimized using c...

The prediction of certain thermodynamic properties of pure substances and mixtures with calculation methods is a frequent task during the process design in chemical engineering. Group contribution models divide the molecules into functional groups and if the model parameters for theses groups are known, predictions of compounds that comprise these groups are possible. The model parameters have ...

A simple diffusion apparatus has been described in which a layer of solution is allowed to diffuse upward into a layer of solvent. Accurate sampling is performed at various heights and the concentration of the samples is determined. The method has been illustrated with a determination of the diffusion constant of crystalline catalase, which was found to be 3.1 x 10(-7) cm.(2)/sec. at 4 degrees ...

Salicylic acid has one of its characteristics the allelopathic potential. The present paper, is a research quantitative in nature aimed to assess potential salicylic identify best concentration range for other pure substances. bioassays were performed BOD incubator, seeking seedling growth by measuring radicle and hypocotyl length. Each bioassay occurred 12 days. concentrations used were: 1000,...

Antiviral interferon activity in any one species can be exhibited by a variety of substances that differ in their physical and chemical properties, but the nature of these differences is not understood. Conditions that can lead to the formation of diverse types of interferons have been outlined. Reasons have been adduced why, for certain purposes, purification of interferons is desirable or eve...

Although their existence and, indeed, some of their effects on human and animal health have been known for some time, the first mycotoxin was positively identified and chemically characterized in the early 1960s (Nesbit et al., 1962). Mycotoxins have been linked to one of the ‘‘ten plagues of Egypt’’ as described in both the Ipuwer papyrus and the Bible. In recent times, numerous additions have...