The Effects of Lithium on a Neuronal in Vitro Orcadian Pacemaker

Previous studies have suggested a causal connection between abnormalities of the circadian system and affective disorders. The effectiveness of lithium or rubidium as a treatment for affective disorders and the ability of lithium or rubidium to influence circadian pacemakers has stimulated research into the mechanism of lithium's action on circadian systems. In this study we used a neuronal in vitro circadian pacemaker preparation, the eye of the mollusc Bulla, to examine the cellular effects of lithium and rubidium. Continuous extracellular LiCl application lengthens the period of the circadian rhythm of the Bulla pacemaker in a concentration-dependent manner. Rubidium was found to be more effective than lithium in period lengthening. Stable phase delays were generated by 2-h pulses of 395 mM LiCl applied extracellularly from zeitgeber time (ZT) 5-7 (mid subjective day). Concomitant continuous application of 16 mM LiCl and light (a depolarizing agent) generated period lengthening substantially greater than the arithmetic sum of the modest period lengthening of each treatment alone. Furthermore, LiCl pulses, applied together with depolarizing extracellular KC1 concentrations, yielded an increasing magnitude of phase delays with increasing KC1 concentration. These data suggest that LiCl acts intracellularly on the circadian pacemaker cells by entering through a voltage-dependent channel, most likely a sodium channel.     

Codivergence but Limited Covariance of Wing Shape and Calling Song Structure in Field Crickets (<Emphasis Type="Italic">Gryllus</Emphasis>)

Morphological traits are often used in performing ecological tasks or in sexual display behaviour. Variation in morphology is thus expected to be coupled to variation in idiosyncratic behaviours across ecologically or sexually diverged lineages. However, it is poorly understood whether this prediction holds and how functional constraints, shared ancestry, or selection contribute to morphology-behaviour co-evolution. Here, we test this prediction in four cricket species, which differ strikingly in their sexually selected mate calling songs, produced by engaging their specialized forewings. Using geometric morphometrics we provide the first evidence that wing shape and size varies consistently across species. We then test whether wing shape and song co-evolve and whether co-evolution is best explained by individual-level functional/genetic covariance or by population-level evolutionary covariance. Song structure and wing shape are coupled, even after accounting for phylogeny. However, there is limited covariance within species. Thus, wing morphology and sexual signalling behaviour in crickets are likely linked due to shared (ancestral) effects from neutral and selective processes. We show that morphology and behaviour can be linked across but not within species and discuss how evolutionary stasis, genetic linkage, and evolutionary covariance help explain this pattern.     

Improved method for virological analysis of food

A single, simple method for recovering enteroviruses from several different kinds of food, such as ground beef, fish, oysters, and mussels, has been improved. First, sample contamination technique was studied. It appears that virus adsorption occurs at food pH and varies according to the kind of food and the food-virus exchange surface. Second, virus recovery was evaluated. According to the experimental results obtained, we propose the following method. Samples are submerged in 100 ml of demineralized water adjusted to pH 9 with a conductivity of 8,000 mg of NaCl per liter. Then, viruses are concentrated by ultrafiltration or by ultracentrifugation. This method was efficient for virus recovery from the four kinds of food, even in cases of very low contamination.     

Survival of enteric viruses adsorbed on glass microfibers during postal transport

The survival of enteric viruses (poliovirus type 1, Mahoney strain, and indigenous viruses of waste waters) has been studied after adsorption of the viruses (pH 3.5) on glass microfiber filters. After postal transport, the presence of the viruses was checked on the filters being soaked in a 3% beef extract solution (pH 7.5) either frozen or without protection against heat. Viruses were recovered at a rate of 59 to 65%. For qualitative studies, postal shipment of samples adsorbed on fiberglass may allow extension of a control system for enteroviruses in water.     

Drought affects the rate and duration of organ growth but not inter-organ growth coordination

Drought at flowering and grain filling greatly reduces maize (Zea mays) yield. Climate change is causing earlier and longer-lasting periods of drought, which affect the growth of multiple maize organs throughout development. To study how long periods of water deficit impact the dynamic nature of growth, and to determine how these relate to reproductive drought, we employed a high-throughput phenotyping platform featuring precise irrigation, imaging systems, and image-based biomass estimations. Prolonged drought resulted in a reduction of growth rate of individual organs—though an extension of growth duration partially compensated for this—culminating in lower biomass and delayed flowering. However, long periods of drought did not affect the highly organized succession of maximal growth rates of the distinct organs, i.e. leaves, stems, and ears. Two drought treatments negatively affected distinct seed yield components: Prolonged drought mainly reduced the number of spikelets, and drought during the reproductive period increased the anthesis-silking interval. The identification of these divergent biomass and yield components, which were affected by the shift in duration and intensity of drought, will facilitate trait-specific breeding toward future climate-resilient crops.

When affected by drought, the plant responds by adjusting the growth of individual organs but not the coordination between the organs.