Fragrance analyses,an aid to taxonomic relationships of the genusCoryanthes (Orchidaceae)

All members of the investigated genusCoryanthes (subtribeStanhopeinae) are pollinated by male euglossine bees. The different fragrance profiles are the primary reproductive isolating mechanisms, because the flowers are interfertile. The fragrance patterns of 17 species ofCoryanthes were analyzed by gas chromatography as a means to improve the classification of this genus. A first amine (2-N-methylaminobenzaldehyde) was found to be the main fragrance compound of an as yet unclassifiedCoryanthes species.     

Validation of scales and otoliths for estimating age of redband trout in high desert streams of Idaho

Studies validating aging structures for rainbow trout are sparse and none have been conducted for redband trout, a common western U.S. sub-species. Oxytetracycline mark-recapture methods (MR), marginal incremental analysis (MIA), and comparisons across multiple populations were used to evaluate the utility of two structures for aging redband trout in high desert streams. We assessed periodicity of annulus formation on scale and otolith samples from all age classes of trout residing in two streams, identified the location of the first annulus on otoliths, and compared age estimates and between-reader coefficient of variation on nine additional streams. The use of MIA successfully validated opaque zone periodicity for fish transitioning from age-0 to age-1, and from age 1 to age 2 in two streams. For fish at liberty 13 and 28 months in the same two streams, MR-derived age estimates from whole and sectioned otoliths were 94–100% accurate for fish from 2–9 years old. Scales were only 77% and 38% accurate for fish at liberty 13 and 28 months, respectively. Between-reader coefficient of variation (CV) for scales was high (11.5%), while CV for sectioned otoliths using whole otoliths as corroboratory structures averaged 2.3%. Scales were thus, an unacceptable aging structure for desert redband trout. Given the confusion in the literature, we suggest that more rigorous research should be conducted to define and explain otolith zone formation.     

Comparing the Quality of Crowdsourced Data Contributed by Expert and Non-Experts

There is currently a lack of in-situ environmental data for the calibration and validation of remotely sensed products and for the development and verification of models. Crowdsourcing is increasingly being seen as one potentially powerful way of increasing the supply of in-situ data but there are a number of concerns over the subsequent use of the data, in particular over data quality. This paper examined crowdsourced data from the Geo-Wiki crowdsourcing tool for land cover validation to determine whether there were significant differences in quality between the answers provided by experts and non-experts in the domain of remote sensing and therefore the extent to which crowdsourced data describing human impact and land cover can be used in further scientific research. The results showed that there was little difference between experts and non-experts in identifying human impact although results varied by land cover while experts were better than non-experts in identifying the land cover type. This suggests the need to create training materials with more examples in those areas where difficulties in identification were encountered, and to offer some method for contributors to reflect on the information they contribute, perhaps by feeding back the evaluations of their contributed data or by making additional training materials available. Accuracies were also found to be higher when the volunteers were more consistent in their responses at a given location and when they indicated higher confidence, which suggests that these additional pieces of information could be used in the development of robust measures of quality in the future.     

A Conspicuous Connection: Structure Defines Function for the Phosphatidylinositol-Phosphate Kinase Family

ABSTRACT

The phosphatidylinositol phosphate (PIP) kinases are a unique family of enzymes that generate an assortment of lipid messengers, including the pivotal second messenger phosphatidylinositol 4,5-bisphosphate (PI4,5P₂). While members of the PIP kinase family function by catalyzing a similar phosphorylation reaction, the specificity loop of each PIP kinase subfamily determines substrate preference and partially influences distinct subcellular targeting. Specific protein-protein interactions that are unique to particular isoforms or splice variants play a key role in targeting PIP kinases to appropriate subcellular compartments to facilitate the localized generation of PI4,5P₂ proximal to effectors, a mechanism key for the function of PI4,5P₂ as a second messenger. This review documents the discovery of the PIP kinases and their signaling products, and summarizes our current understanding of the mechanisms underlying the localized generation of PI4,5P₂ by PIP kinases for the regulation of cellular events including actin cytoskeleton dynamics, vesicular trafficking, cell migration, and an assortment of nuclear events.     

Trehalose and vitreous states: desiccation tolerance of dormant stages of the crustaceans Triops and Daphnia

Several aquatic organisms are able to withstand extreme desiccation in at least one of their life stages. This is commonly known as "anhydrobiosis." It was often thought that to tolerate such a desiccated state required high amounts of compatible solutes such as the nonreducing disaccharide trehalose, which protects cellular structures by water replacement and glass formation. Trehalose levels of dormant eggs and cysts of five freshwater crustaceans (Daphnia magna, Daphnia pulex, Triops longicaudatus, Triops cancriformis, and Triops australiensis) were observed in different states of hydration and dehydration. Although trehalose was detected in all species, the concentration was under 0.5% of the dry weight (0.05 μg/μg protein), and no change between the different states was observed. Differential scanning calorimetry (DSC) measurements indicated that dried cysts of all Triops species were in a glassy state, supporting the vitrification hypothesis. No indication for a vitreous state was found in dried resting eggs of Daphnia.     

Solubilization of sphingomyelin vesicles by addition of a bile salt

The interactions of the bile salt sodium taurocholate (TC) in 50 mM Trizma-HCl buffer and 150 mM NaCl (pH 9) at 37 degrees C with membranes composed of sphingomyelin (SM) were studied by dynamic light scattering, cryogenic transmission electron microscopy (cryo-TEM) and turbidity measurements. Small unilamellar SM vesicles were prepared by extrusion. Below the CMC of TC, taurocholate addition leads to vesicle growth due to incorporation of the taurocholate molecules into the vesicle bilayer. At around half the CMC of the bile salt, the SM vesicles are transformed into SM/TC mixed worm-like micelles, which are visualized by cryo-TEM for the first time. Further increase in the taurocholate concentration leads to the rupture of these structures into small spherical micelles. Interestingly, large non-spherical micelles were also identified for pure taurocholate solutions. Similar threadlike structures have been reported earlier for the bile salt sodium taurodeoxycholate [Rich, A., Blow, D., 1958. Nature 182, 1777; Blow, D.M., Rich, A., 1960. J. Am. Chem. Soc. 82, 3566-3571; Galantini, L., Giglio, E., La Mesa, C., Viorel-Pavel, N., Punzo, F., 2002. Langmuir 18, 2812] and for mixtures of taurocholate and phosphatidylcholate [Ulmius, J., Lindblom, G., Wennerstr?m, H., Johansson, L.B.-A., Fontel, K., S?derman, O., Ardvisson, G., 1982. Biochemistry 21, 1553; Hjelm, R.P., Thiyagarajan, P., Alkan-Onyuksel, H., 1992. J. Phys. Chem. 96, 8653] as determined by various scattering methods.     

Trehalose and anhydrobiosis in tardigrades--evidence for divergence in responses to dehydration

To withstand desiccation, many invertebrates such as rotifers, nematodes and tardigrades enter a state known as anhydrobiosis, which is thought to require accumulation of compatible osmolytes, such as the non-reducing disaccharide trehalose to protect against dehydration damage. The trehalose levels of eight tardigrade species comprising Heterotardigrada and Eutardigrada were observed in five different states of hydration and dehydration. Although many species accumulate trehalose during dehydration, the data revealed significant differences between the species. Although trehalose accumulation was found in species of the order Parachela (Eutardigrada), it was not possible to detect any trehalose in the species Milnesium tardigradum and no change in the trehalose level has been observed in any species of Heterotardigrada so far investigated. These results expand our current understanding of anhydrobiosis in tardigrades and, for the first time, demonstrate the accumulation of trehalose in developing tardigrade embryos, which have been shown to have a high level of desiccation tolerance.     

Heat shock proteins (Hsp70) and water content in the estivating Mediterranean Grunt Snail (Cantareus apertus)

Pulmonate land snails often are able to estivate to survive dry hot seasons were water and food are scarce. The aperture of the shell is closed with an epiphragm, and metabolism is depressed to approximately one fourth of basal metabolism. We investigated a molecular aspect of estivation focussing on the heat shock protein 70 (Hsp70) stress response during estivation in the Mediterranean Grunt Snail Cantareus apertus. Sequences of a new inducible hsp70 and of actin are presented and expression of the hsp70 gene as well as Hsp70 protein content was measured in estivating animals. Both Hsp70 protein and mRNA do not show a significant change from the control, although there is a trend that hsp70 mRNA is less abundant in estivating specimens. After heat shock, the expression of hsp70 increased and a higher Hsp70 protein content was detected. Water relations were also investigated. After a period of 6 months in the dormant state, the snails contained 14% less water than active ones, implying a constricted protection against desiccation, compared to the desert snail Sphincterochila zonata, and a Mediterranean-type water economy.