The search for worlds like our own.

The direct detection of Earth-like exoplanets orbiting nearby stars and the characterization of such planets-particularly, their evolution, their atmospheres, and their ability to host life-constitute a significant problem. The quest for other worlds as abodes of life has been one of mankind's great questions for several millennia. For instance, as stated by Epicurus approximately 300 BC: "Other worlds, with plants and other living things, some of them similar and some of them different from ours, must exist." Demokritos from Abdera (460-370 BC), the man who invented the concept of indivisible small parts-atoms-also held the belief that other worlds exist around the stars and that some of these worlds may be inhabited by life-forms. The idea of the plurality of worlds and of life on them has since been held by scientists like Johannes Kepler and William Herschel, among many others. Here, one must also mention Giordano Bruno. Born in 1548, Bruno studied in France and came into contact with the teachings of Nicolas Copernicus. He wrote the book De l'Infinito, Universo e Mondi in 1584, in which he claimed that the Universe was infinite, that it contained an infinite amount of worlds like Earth, and that these worlds were inhabited by intelligent beings. At the time, this was extremely controversial, and eventually Bruno was arrested by the church and burned at the stake in Rome in 1600, as a heretic, for promoting this and other equally confrontational issues (though it is unclear exactly which idea was the one that ultimately brought him to his end). In all the aforementioned cases, the opinions and results were arrived at through reasoning-not by experiment. We have only recently acquired the technological capability to observe planets orbiting stars other than 6 our Sun; acquisition of this capability has been a remarkable feat of our time. We show in this introduction to the Habitability Primer that mankind is at the dawning of an age when, by way of the scientific method and 21(st)-century technology, we will be able to answer this fascinating controversial issue that has persisted for at least 2500 years.

Bradykinin-related peptides, including a novel structural variant, (Val1)-bradykinin, from the skin secretion of Guenther's frog, Hylarana guentheri and their molecular precursors.

Multiple bradykinin-related peptides including a novel bradykinin structural variant, (Val(1))-bradykinin, have been identified from the defensive skin secretion of Guenther's frog, Hylarana guentheri by a tandem mass spectrometry method. Subsequently, four different preprobradykinin cDNAs, which encoded multiple bradykinin copies and its structural variants, were consistently cloned from a skin derived cDNA library. These preprobradykinin cDNAs showed little structural similarity with mammalian kininogens and the kininogens from the skin of toads, but have regions that are highly conserved in the kininogens from another ranid frog, Odorrana schmackeri. Alignment of these preprobradykinins revealed that preprobradykinin 1, 2 and 3 may derive from a single gene by alternative exon splicing.

The characterisation of selected drugs with amine-containing side chains using electrospray ionisation and ion trap mass spectrometry and their determination by HPLC-ESI-MS.

The electrospray ionisation-ion-trap mass spectrometry (ESI-MS(n)) of selected drug compounds with amine-containing side chains has been investigated. Certain characteristic in-source fragmentations have been observed for these molecules. Sequential product ion fragmentation experiments (MS(n)) have been performed in order to elucidate the degradation pathways for the [M + H](+) ions and their predominant fragment ions. These MS(n) experiments also show certain characteristic fragmentations with respect to the amine-containing side chains. QTOF-MS/MS has been used to support the identity of the proposed fragments. The data presented in this paper therefore provides useful information on the structure of these compounds with amine-containing side chains and can be used in the characterisation of such drugs, their structurally related metabolites and unknown molecules of pharmaceutical significance extracted from animal and plant sources, for example. Amphetamine, clenbuterol, flurazepam and methadone can be identified and determined in mixtures at low ng/ml concentrations by the application of HPLC-ESI-MS which can also be used for their analysis in saliva samples.

Characterisation of selected drugs with nitrogen-containing saturated ring structures by use of electrospray ionisation with ion-trap mass spectrometry.

The electrospray ionisation-ion-trap mass spectrometry (ESI-MS(n)) of selected drugs with nitrogen-containing saturated ring structures has been investigated. Sequential product-ion fragmentation experiments (MS(n)) have been performed to elucidate degradation pathways for the [M+H](+) ions and their predominant fragment ions. These MS(n) experiments result in characteristic fragmentations in which functional groups are generally cleaved from the ring systems as neutral molecules such as H(2)O, amines, alkenes, esters, carboxylic acids, etc. When such a nitrogen-containing drug molecule also contains a functional group, such as an ester, that on liberation as a neutral molecule has a significantly lower -Delta H(f) degrees value than that of the corresponding amine then the former is preferentially liberated. Furthermore, when an aromatic entity is present in these drug molecules together with the nitrogen-containing saturated ring structure fragmentation of the latter ring occurs with the former, predictably, being resistant to fragmentation. The structures of fragment ions proposed for ESI-MS(n) can be supported by electrospray ionisation-quadrupole time-of-flight mass spectrometry (ESI-QTOFMS). The data presented in this paper therefore provide useful information on the structure of these heterocyclic compounds which could be used to characterise unknown drug compounds isolated from natural sources, for example.

Kinestatin: a novel bradykinin B2 receptor antagonist peptide from the skin secretion of the Chinese toad, Bombina maxima.

We have isolated a novel bradykinin B(2)-receptor antagonist peptide, kinestatin, from toad (Bombina maxima) defensive skin secretion. Mass spectroscopy established a molecular mass of 931.56 Da and a provisional structure: pGlu-Leu/Ile-Pro-Gly-Leu/Ile-Gly-Pro-Leu/Ile-Arg.amide. The unmodified sequence, -QIPGLGPLRG-, was located at the C-terminus of a 116-amino-acid residue open-reading frame following interrogation of a sequenced B. maxima skin cDNA library database. This confirmed the presence of appropriate primary structural attributes for the observed post-translational modifications present on the mature peptide and established residue 2 as Ile and residues 5/8 as Leu. Kinestatin represents a prototype novel peptide from amphibian skin.