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We have determined by reverse Southern analysis and direct sequence comparisons that most of the dumpy gene has evolved in the dipteran and other insect orders by purifying selection acting on amino acid replacements. One region, however, is evolving rapidly due to unequal crossing over and/or gene conversion. This region, called 'PIGSFEAST,' or PF, encodes in D. melanogaster 30-47 repeats of 102 amino acids rich in serines, threonines, and prolines. We show that the processes of concerted evolution have been operating on all species of Drosophila examined to date, but that an adjacent region has expanded in Anopheles gambiae, Aedes aegypti, and Tribolium castaneum, while the PF repeats are reduced in size and number. In addition, processes of concerted evolution have radically altered the codon usage patterns in D. melanogaster, D. pseudoobscura, and D. virlis compared with the rest of the dumpy gene. We show also that the dumpy gene is expressed on the inner surface of the micropyle of the mature oocyte and propose that, as in the abalone system, concerted evolution may be involved in adaptive changes affecting Dumpy's possible role in sperm-egg recognition.

A palaeomagnetic study of different lithologies exposed along the Moine Thrust Zone from Skye to Durness, Scotland, has identified three chemical remanent magnetizations (CRMs), a potential fourth CRM, and one possible primary component that all reside in hematite. Local and regional fold tests suggest that the CRMs are post-folding and post-thrusting. A contact test in the Torridon Group sandstone indicates that a Permian CRM is localized in and near the fault zone. The Permian CRM, which is also found in the Durness Group, and associated alteration are direct evidence for post-orogenic activity, in which the thrusts vented excess heat during regional crustal extension. On the Isle of Skye, sandstones (Sleat, Torridon and Eriboll Groups) in and around the fault zone contain a Tertiary CRM interpreted to be related to hydrothermaI fluids associated with Tertiary intrusions. A possible Mesozoic CRM is also present but it could represent the vector addition of the Permian and Tertiary CRMs. A Devonian CRM is interpreted to be related to hydrothermal fluids associated with Devonian volcanic rocks or to fluids triggered by late stages of the Caledonian orogeny. Geochemical and petrographical studies provide supporting evidence for multiple fluid flow events along the Moine Thrust Zone. These results show that palaeomagnetism can be used to date multiple fluid migration events and that dormant fault zones can act as conduits for flow. Keywords: Moine Thrust Zone, remagnetization, fluid migration events.

The 24-km-diameter Tertiary Haughton impact structure formed in rocks that contained preexisting liquid hydrocarbons. Biomarker ratios in the hydrocarbons show a consistent pattern of variation in degree of heating across the structure. The heating reached a maximum at the crater center and is attributed to hydrothermal activity following impact. Kinetic modeling suggests a time scale of ~5 k.y. for the heating, at a maximum temperature of 210 [degrees]C. The short time scale suggests that in moderate-sized craters, which are abundant on Mars, heating is not so extensive that fossil or extant organic matter would be obliterated. Keywords: Haughton impact structure, impact craters, biomarkers, thermal maturity, thermal alteration, Mars.

In Drosophila, Suppressor of deltex (Su(dx)) mutations display a wing vein gap phenotype resembling that of Notch gain of function alleles. The Su(dx) protein may therefore act as a negative regulator of Notch but its activity on actual Notch signalling levels has not been demonstrated. Here we show that Su(dx) does regulate the level of Notch signalling in vivo, upstream of Notch target genes and in different developmental contexts, including a previously unknown role in leg joint formation. Overexpression of Su(dx) was capable of blocking both the endogenous activity of Notch and the ectopic Notch signalling induced by the overexpression of Deltex, an intracellular Notch binding protein. In addition, using the conditional phenotype of the [Su(dx).sup.sp] allele, we show that loss of Su(dx) activity is rapidly followed by an up-regulation of E(spl)m[beta] expression, the immediate target of Notch signal activation during wing vein development. While Su(dx) adult wing vein phenotypes are quite mild, only affecting the distal tips of the veins, we show that the initial consequence of loss of Su(dx) activity is more severe than previously thought. Using a time-course experiment we show that the phenotype is buffered by feedback regulation illustrating how signalling networks can make development robust to perturbation. Keywords: Notch; Suppressor of deltex; Drosophila; Ubiquitin ligase

The Notch receptor signaling pathway regulates cell differentiation during the development of multicellular organisms. A number of genes are known to be components of the pathway or regulators of the Notch signal. One candidate for a modifier of Notch function is the Drosophila Suppressor of deltex gene [Su(dx)]. We have isolated four new alleles of Su(dx) and mapped the gene between 22B4 and 22C2. Loss-of-function Su(dx) mutations were found to suppress phenotypes resulting from loss-of-function of Notch signaling and to enhance gain-of-function Notch mutations. Hairless, a mutation in a known negative regulator of the Notch pathway, was also enhanced by Su(dx). Phenotypes were identified for Su(dx) in wing vein development, and a role was demonstrated for the gene between 20 and 30 hr after puparium formation. This corresponds to the period when the Notch protein is involved in refining the vein competent territories. Taken together, our data indicate a role for Su(dx) as a negative regulator of Notch function.

A yeast expression method changes the amino terminus of human fibronectin into a recombinant protein, using a two-dimensional homonuclear H nuclear magnetic resonance (NMR) spectroscopy. The method involves a combination of 2DH nuclear Overhauser effect (NOE) spectroscopy, homonuclear Hartmann-Hahn and dependent spectroscopy and spectra tabulated under several pH and temperature conditions. NMR results show minute reorientation of the two modules around the linker area. The two modules combine under fixed hydrophobic conditions.

Few words were uttered more often during this conference than 'Wall Street.' What follows are edited excerpts from various sessions, all of which focus attention on the tug that Wall [...]

Compares self-report measures of depression and psychological distress in U.S. and Japanese university students. Reassesses sex differences on these measures for U.S. students and examines sex differences for Japanese students. Finds that Japanese students had higher scores on depression measures but not on psychological distress. (Author/ LS)

The effect of the support on oxidative dehydrogenation activity for vanadia/ceria systems is investigated for the oxidation of methanol to formaldehyde by using well-defined V[O.sub.x]/Ce[O.sub.2](111) model catalysts. Density functional theory is applied and the energies of hydrogenation and oxygen vacancy formation have predicted an increased reactivity of the vanadia/ceria system.

Signaling by receptor tyrosine kinases (RTKs) is critical for a multitude of developmental decisions and processes. Among the molecules known to transduce the RTK-generated signal is the nonreceptor protein tyrosine phosphatase Corkscrew (Csw). Previously, Csw has been demonstrated to function throughout the Drosophila life cycle and, among the RTKs tested, Csw is essential in the Torso, Sevenless, EGF, and Breathless/FGF RTK pathways. While the biochemical function of Csw remains to be unambiguously elucidated, current evidence suggests that Csw plays more than one role during transduction of the RTK signal and, further, the molecular mechanism of Csw function differs depending upon the RTK in question. The isolation and characterization of a new, spontaneously arising, viable allele of csw, [csw.sup.lf] has allowed us to undertake a genetic approach to identify loci required for Csw function. The rough eye and wing vein gap phenotypes exhibited by adult flies homo- or hemizygous for [csw.sup.lf] has provided a sensitized background from which we have screened a collection of second and third chromosome deficiencies to identify 33 intervals that enhance and 21 intervals that suppress these phenotypes. We have identified intervals encoding known positive mediators of RTK signaling, e.g., drk, dos, Egfr, E(Egfr)B56, pnt, Ras1, rolled/MAPK, sina, spen, Src64B, Star, Su(Raf)3C, and vein, as well as known negative mediators of RTK signaling, e.g., aos, ed, net, Src42A, sty, and su(ve). Of particular interest are the 5 lethal enhancing intervals and 14 suppressing intervals for which no candidate genes have been identified.

Kaolinite and dickite occur widely in central Scotland and Northern Ireland. Stable hydrogen and oxygen isotope compositions of both minerals are similar, suggesting that the formation of kaolinite occurred first at temperatures of [is less than] 50 [degrees] C from meteoric water, probably as a result of alteration of Lower Carboniferous volcanic rocks, and that dickitization followed locally as a result of local heating that accompanied the intrusion of dykes during Late Carboniferous--Permian times. This mechanism of dickite formation explains why the higher-temperature polytype dickite occurs in a region from the Firth of Clyde to Perthshire, in association with dyke swarms, whilst kaolinite occurs elsewhere. The original kaolinite precipitation was focused along the high permeability fault zone now marked by the Highland Boundary Fault Zone and its presumed trace in Northern Ireland. Keywords: Scotland, kaolin, kaolinite, dickite, palaeotemperature.