Exponential gradient maker using a disposable syringe

With a simple modification, any disposable syringe can become a reliable and easy to use exponential gradient maker. The modification consists of two notches, made with a razor blade, in the borders of the rubber sealing tip of the plunger. A clamp in the tube connected to the syringe allows control over solution flow. With the clamp prohibiting drainage, the body of the syringe is filled with the desired volume of starting solution I. A magnetic stir bar, small enough to spin inside the syringe is included. The notched plunger is introduced until no air space remains. This forms the fixed volume, closed mixing chamber, while the rest of the volume of the syringe forms the open chamber. The two chambers are connected through the notches in the plunger. The ending solution II is poured after the introduction of the plunger. Opening the clamp allows solution I in the closed chamber to flow out, and the solution II in the open chamber flows through the notches and mixes with solution I. This exponential gradient maker can be reused many times, but the low cost of the components makes it potentially disposable. This feature is especially useful when using toxic chemicals, or when pouring polyacrylamide gradient gels, since the apparatus may be disposed of after contamination or eventual polymerization.     

Movement patterns of forest elephants (Loxodonta cyclotis Matschie, 1900) in the Odzala-Kokoua National Park,Republic of Congo

African forest elephants (Loxodonta cyclotis Matschie, 1900) are ecological engineers that play a fundamental role in vegetation dynamics. The species is of immediate conservation concern, yet it is relatively understudied. To narrow this knowledge gap, we studied the drivers of daily movement patterns (linear displacements) of forest elephants—characterised by a set of geographical, meteorological and anthropogenic variables—in the Odzala-Kokoua National Park, Republic of Congo. Explicitly, we used conditional random forest to model and disentangle the main environmental factors governing the displacements of six forest elephants, fitted with GPS collars and tracked over 16 months. Results indicated that females moved further distances than males, while the presence of roads or human settlements disrupted elephant behaviour resulting in faster displacements. Forest elephants moved faster along watercourses and through forest with understory dominated by Marantaceae forests and bais, but moved slower in savannahs. Finally, flood-prone areas—described by elevation and accumulated precipitation—and higher temperatures prevented longer displacements. We expect these results to improve the knowledge on the species movements through different habitats, which would benefit its conservation management.     

Distribution of alien vs. native plant species in roadside communities along an altitudinal gradient in Tenerife and Gran Canaria (Canary Islands)

Roadside plant communities were studied along two roads following an altitudinal gradient in Gran Canaria and Tenerife (Canary Islands). Our aim was to investigate variation in plant species richness, particularly of the alien flora, along a gradient from coastal shrubland to summit vegetation (1950 m a.s.l. in Gran Canaria, 2300 m in Tenerife) in relation to variation in habitat factors (altitude, habitat structure, roadside disturbance, distance to urban nuclei). We compared different species groups that were classified in terms of their biogeographical status, origin and life form. Altitude was the most important factor determining species richness and composition along both roadside transects. Alien plants showed a unimodal distribution pattern along the altitudinal gradient, with less species and lower abundance at low and high altitudes, and highest abundance at intermediate altitude. Alien plant species were also relatively more frequent near urban centres. The number of native and alien species was significantly positively correlated along the altitudinal gradient. Both alien and native, non-endemic species showed differences in their distribution along the altitudinal gradient according to their biogeographical affinities and climatic tolerances. Despite considerable differences in species pools these patterns were consistent among the two islands. Environmental (abiotic) stress is proposed as a primary, altitude-related factor acting as a filter against most alien plants at coastal and high-mountain altitudes. A higher frequency or intensity of disturbance at intermediate altitudes may be a further causal factor promoting alien plants in this zone. Future management efforts to control alien plants along roads should, therefore, concentrate on intermediate altitudinal zones of the higher Canary Islands.     

Preliminary assessment of the release of captive-bred Gran Canaria Blue Chaffinches Fringilla teydea polatzeki as a reinforcement population

Capsule: The endangered Gran Canaria Blue Chaffinch Fringilla teydea polatzeki has been bred in captivity with the aim of reinforcing wild populations. We released and monitored 26 males and 15 females between 2010 and 2012. Survival and reproductive success were similar between the reinforced population and a stable reference population, suggesting that the process could be useful for the conservation of the species.     

Comparison of seed and vegetative propagation methods for red squill

Seed propagation was found more profitable than any of three vegetative methods investigated for multiplying this source of a very specific raticide.     

High-performance liquid chromatographic determination of diuretics in urine by micellar liquid chromatography

The use of micellar liquid chromatography for the determination of diuretics in urine by direct injection of the sample into the chromatographic system is discussed. The retention of the urine matrix at the beginning of the chromatograms was observed for different sodium dodecyl sulphate (SDS) mobile phases. The eluent strengths of a hybrid SDS—methanol micellar mobile phase for several diuretics were compared and related to the stationary phase/water partition coefficient with a purely micellar mobile phase. The urine band was appreciably narrower with a mobile phase of 0.05 M SDS—5% methanol (v/v) at 50°C (pH 6.9). With this mobile phase the determination of bendroflumethiazide and chlorthalidone was adequate. Acetazolamide, ethacrynic acid, furosemide, hydrochlorothiazide and probenecid were overlapped by the urine matrix, and the retention of amiloride and triamterene was too long.     

Lack of evidence for proofreading mechanisms associated with an RNA virus polymerase.

The in vitro fidelity of the virion-associated RNA polymerase of vesicular stomatitis virus was quantitated for a single conserved viral RNA site and the usual high in vitro base misincorporation error frequencies (approx. 10(-3)) were observed at this (guanine) site. We sought evidence for RNA 3'-->5' exonuclease proofreading mechanisms by varying the concentrations of the next nucleoside triphosphate, by incorporation of nucleoside[1-thio]triphosphate analogues of the four natural RNA nucleosides, and by varying the concentrations of pyrophosphate in the in vitro polymerase reaction. None of these perturbations greatly affected viral RNA polymerase fidelity at the site studied. These results fail to show evidence for proofreading exonuclease activity associated with the virion replicase of an RNA virus. They suggest that RNA virus replication might generally be error-prone, because RNA replicase base misincorporations are proofread very inefficiently or not at all.