Platinum toxicity and gene expression in Xenopus embryos: analysis by FETAX and differential display

Since the level of platinum in the environment is destined to increase, because of its use in vehicle catalytic converters, the toxicity of platinum needs further investigation. In this study, the frog embryo teratogenesis assay-Xenopus (FETAX) was used to compare the embryotoxicity and teratogenicity of two common platinum species, (NH4)2PtCl4 and (NH4)2PtCl6. The uptake rates of the two platinum species were studied, and also their effects on the expression of genes encoding metallothionein and heat-shock protein 70, which are known to be induced by several stress factors. In addition, the differential display technique was used to search for genes that were specifically induced by platinum. A gene for the type I collagen alpha-chain and a novel gene were identified.     

Enhanced Slow-Wave EEG Activity and Thermoregulatory Impairment following the Inhibition of the Lateral Hypothalamus in the Rat

Neurons within the lateral hypothalamus (LH) are thought to be able to evoke behavioural responses that are coordinated with an adequate level of autonomic activity. Recently, the acute pharmacological inhibition of LH has been shown to depress wakefulness and promote NREM sleep, while suppressing REM sleep. These effects have been suggested to be the consequence of the inhibition of specific neuronal populations within the LH, i.e. the orexin and the MCH neurons, respectively. However, the interpretation of these results is limited by the lack of quantitative analysis of the electroencephalographic (EEG) activity that is critical for the assessment of NREM sleep quality and the presence of aborted NREM-to-REM sleep transitions. Furthermore, the lack of evaluation of the autonomic and thermoregulatory effects of the treatment does not exclude the possibility that the wake-sleep changes are merely the consequence of the autonomic, in particular thermoregulatory, changes that may follow the inhibition of LH neurons. In the present study, the EEG and autonomic/thermoregulatory effects of a prolonged LH inhibition provoked by the repeated local delivery of the GABA_A agonist muscimol were studied in rats kept at thermoneutral (24°C) and at a low (10°C) ambient temperature (Ta), a condition which is known to depress sleep occurrence. Here we show that: 1) at both Tas, LH inhibition promoted a peculiar and sustained bout of NREM sleep characterized by an enhancement of slow-wave activity with no NREM-to-REM sleep transitions; 2) LH inhibition caused a marked transitory decrease in brain temperature at Ta 10°C, but not at Ta 24°C, suggesting that sleep changes induced by LH inhibition at thermoneutrality are not caused by a thermoregulatory impairment. These changes are far different from those observed after the short-term selective inhibition of either orexin or MCH neurons, suggesting that other LH neurons are involved in sleep-wake modulation.     

Native woodland creation is associated with increase in a Black Grouse Lyrurus tetrix population

Capsule: Black Grouse population increases were greatest where new native woodland (NNW) within 1500?m of leks comprised approximately 30% of land area and averaged 5 years old.

Aims: To examine whether change in a population of Black Grouse Lyrurus tetrix in Scotland was associated with the creation of native woodland.

Methods: We examined whether lek location, size and change in size were associated with habitat and topography surrounding leks. We also examined vegetation differences in NNW and adjacent unplanted moorland.

Results: From 2002 to 2012 the number of lekking male Black Grouse increased by 90%. Lek occurrence was positively associated with the amount of NNW edge habitat. Leks were larger where there was more adjacent NNW. Lek increases were greatest where NNW plots comprised approximately 30% land area, and were 5 years old, within a 1500?m radius. Plots aged more than approximately 20 years old were associated with Black Grouse population declines. NNW supported taller and denser important field-layer vegetation than adjacent moorland, likely due to grazing exclusion.

Conclusions: Subject to longer-term management commitments to stimulate continued regrowth of the important field layer and maintain benefits for Black Grouse, expansion of native woodland could contribute to landscape-scale recovery of Black Grouse after decades of decline.     

Spatial proximity between two host plant species influences oviposition and larval distribution in a leaf beetle

Everything else being equal, insect herbivores can be expected to oviposit on host plants that provide the qualitatively and quantitatively best food for larvae. However, the selection of a plant for oviposition may be influenced by such ecological factors as natural enemies, host distribution, host patch size or host patch density. We performed a field study to test whether spatial proximity between two host plant species influences the oviposition patterns and larval distribution of the alpine leaf beetle Oreina elongata. In the population studied, O. elongata oviposits and feeds on two host plants, that belong to the same family (Asteraceae): Adenostyles alliariae and Cirsiumspinosissimum. The first species contains pyrrolizidine alkaloids that are sequestered by the beetle as a chemical defence, whereas the second plant does not contain any alkaloids but has hairy and spiny leaves that might give some mechanical protection to beetle larvae.
During two consecutive summers, we quantified oviposition and larval distribution on randomly chosen C. spinosissimum that grew spatially isolated from A. alliariae, on C. spinosissimum that grew in leaf contact with A. alliariae and on A. alliariae that grew in leaf contact with C. spinosissimum (isolated A. alliariae was not considered, because it is rare in the study population). In both years, more eggs were laid on C. spinosissimum than on A. alliariae and more on those C. spinosissimum that were growing close to A. alliariae than on those growing isolated. Large numbers of larvae moved from C. spinosissimum to A. alliariae during the season. Patch size did not influence egg and larval numbers. Eggs survived better on C. spinosissimum than on A. alliariae in the field. The data suggest that C. spinosissimum may provide eggs with better protection against stormy weather. In a separate study of the same population, we found that larval performance was better on A. alliariae than on C. spinosissimum. Our present data suggest that O. elongata preferentially oviposits on plants of the species that maximizes egg survival and that grow in close proximity to plants of the species that provides better food and chemical defence.     

Stromal upregulation of lateral epithelial adhesions: Gene expression analysis of signalling pathways in prostate epithelium

Background  

Stromal signalling increases the lateral cell adhesions of prostate epithelial cells grown in 3D culture. The aim of this study was to use microarray analysis to identify significant epithelial signalling pathways and genes in this process.