The heritable basis and cost of colour plasticity in coastrange sculpins.

Both genetic and plastic traits contribute to adaptation in novel environments. Phenotypic plasticity can facilitate adaptation by allowing for existence in a wider range of conditions and a faster response to environmental change than gene-based selection. Coastrange sculpins (Cottus aleuticus) colonize new and variable streams arising in the wake of receding glaciers in south-east Alaska, and substrate-matching plasticity may enhance colonization success by reducing detection by visual predators. As part of a long-term study of the fitness consequences of colour plasticity and its capacity to respond to both positive and negative selection, we investigated whether it is heritable and costly. We raised full-sib broods of sculpins in the laboratory: one half of each brood was raised in white containers, the other half in black. After 4 months, we digitally analysed their colour and found significant but weak heritability in both baseline colour and colour plasticity. To investigate the cost of colour plasticity, we compared the growth and mortality rates of juvenile sculpins reared under constant substrate colours to those reared on substrates that changed colour frequently, and compared growth rates among sculpin that differed in their colour change ability. We found evidence of small costs of plasticity, consistent with other studies of natural populations. Evidence of heritable genetic variation for plasticity and small costs to its maintenance and expression contributes to explanations of how plasticity is variable and persistent among wild populations and underscores its ability to respond both positively and negatively to selection in variable habitats.

Pervasive sex-linked effects on transcription regulation as revealed by expression quantitative trait loci mapping in lake whitefish species pairs (Coregonus sp., Salmonidae).

Mapping of expression quantitative trait loci (eQTL) is a powerful means for elucidating the genetic architecture of gene regulation. Yet, eQTL mapping has not been applied toward investigating the regulation architecture of genes involved in the process of population divergence, ultimately leading to speciation events. Here, we conducted an eQTL mapping experiment to compare the genetic architecture of transcript regulation in adaptive traits, differentiating the recently evolved limnetic (dwarf) and benthic (normal) species pairs of lake whitefish. The eQTL were mapped in three data sets derived from an F(1) hybrid-dwarf backcrossed family: the entire set of 66 genotyped individuals and the two sexes treated separately. We identified strikingly more eQTL in the female data set (174), compared to both male (54) and combined (33) data sets. The majority of these genes were not differentially expressed between male and female progeny of the backcross family, thus providing evidence for a strong pleiotropic sex-linked effect in transcriptomic regulation. The subtelomeric region of a linkage group segregating in females encompassed >50% of all eQTL, which exhibited the most pronounced additive effects. We also conducted a direct comparison of transcriptomic profiles between pure dwarf and normal progeny reared in controlled conditions. We detected 34 differentially expressed transcripts associated with eQTL segregating only in sex-specific data sets and mostly belonging to functional groups that differentiate dwarf and normal whitefish in natural populations. Therefore, these eQTL are not related to interindividual variation, but instead to the adaptive and historical genetic divergence between dwarf and normal whitefish. This study exemplifies how the integration of genetic and transcriptomic data offers a strong means for dissecting the functional genomic response to selection by separating mapping family-specific effects from genetic factors under selection, potentially involved in the phenotypic divergence of natural populations.

Mammalian circadian autoregulatory loop: a timeless ortholog and mPer1 interact and negatively regulate CLOCK-BMAL1-induced transcription.

We report the cloning and mapping of mouse (mTim) and human (hTIM) orthologs of the Drosophila timeless (dtim) gene. The mammalian Tim genes are widely expressed in a variety of tissues; however, unlike Drosophila, mTim mRNA levels do not oscillate in the suprachiasmatic nucleus (SCN) or retina. Importantly, hTIM interacts with the Drosophila PERIOD (dPER) protein as well as the mouse PER1 and PER2 proteins in vitro. In Drosophila (S2) cells, hTIM and dPER interact and translocate into the nucleus. Finally, hTIM and mPER1 specifically inhibit CLOCK-BMAL1-induced transactivation of the mPer1 promoter. Taken together, these results demonstrate that mTim and hTIM are mammalian orthologs of timeless and provide a framework for a basic circadian autoregulatory loop in mammals.

Effect of simulated tillage on microbial autotrophic CO2 fixation in paddy and upland soils.

Tillage is a common agricultural practice affecting soil structure and biogeochemistry. To evaluate how tillage affects soil microbial CO2 fixation, we incubated and continuously labelled samples from two paddy soils and two upland soils subjected to simulated conventional tillage (CT) and no-tillage (NT) treatments. Results showed that CO2 fixation ((14)C-SOC) in CT soils was significantly higher than in NT soils. We also observed a significant, soil type- and depth-dependent effect of tillage on the incorporation rates of labelled C to the labile carbon pool. Concentrations of labelled C in the carbon pool significantly decreased with soil depth, irrespective of tillage. Additionally, quantitative PCR assays revealed that for most soils, total bacteria and cbbL-carrying bacteria were less abundant in CT versus NT treatments, and tended to decrease in abundance with increasing depth. However, specific CO2 fixation activity was significantly higher in CT than in NT soils, suggesting that the abundance of cbbL-containing bacteria may not always reflect their functional activity. This study highlights the positive effect of tillage on soil microbial CO2 fixation, and the results can be readily applied to the development of sustainable agricultural management.

Differential expression of the msp130 gene among skeletal lineage cells in the sea urchin embryo: a three dimensional in situ hybridization analysis.

In order to examine the ontogeny of tissue-specific expression of the msp130 gene during early embryogenesis of the sea urchin, we have developed a whole-mount, non-radioactive in situ hybridization protocol suitable for these embryos. This protocol is adapted from the existing technology of immunohistochemical localization of digoxygenin-labelled hybridization probes in tissue sections. Transcript distribution patterns in the whole embryo are seen in three dimensions, and at much higher resolution and sensitivity than can be achieved using radioactive probes and sectioned material. We have traced the ontogeny of expression of the skeleton-specific gene, msp130, during the development of Strongylocentrotus purpuratus. Transcripts are first detected at the blastula stage, in micromere-lineage cells just prior to ingression. Appearance of msp130 transcripts remains strictly limited to this lineage through the pluteus stage. Estimated from the relative intensity of staining of the PMCs of an embryo, the relative abundance of msp130 transcripts is uniform among the 32 cells of this lineage in secondary mesenchyme blastulae and in gastrulae, indicating that expression is homogeneous among these cells up to the early prism stage. However, the relative intensity of stain, and therefore abundance of transcripts, changes dramatically and in a consistent pattern among the PMCs of an embryo during prism and pluteus stages, suggesting that these cells switch from an autonomous mode of regulation of the msp130 gene, to an inductive mode. In the pluteus larva, the highest levels of expression occur in those cells associated with the rapidly growing tips of the spicular skeleton.

The Xenopus clock gene is constitutively expressed in retinal photoreceptors.

Many aspects of normal retinal physiology are controlled by a retinal circadian clock. In Xenopus laevis, the photoreceptor cells within the retina contain a circadian clock that controls melatonin release. In this report we present the cloning and characterization of the Xenopus homolog of the Clock gene, known to be critical for normal circadian behavioral rhythms in the mouse. The Xenopus Clock gene is expressed primarily in photoreceptors within the eye and is expressed at constant levels throughout the day. Analysis of other tissues revealed that, as in other species, the Xenopus Clock gene is widely expressed. This characterization of the Clock gene provides a useful tool for further exploration of the role of the circadian clock in normal retinal function.

High-dose intravenous immunoglobulin in the treatment of Guillain-Barré syndrome: a preliminary open study.

We report the effects of intravenous gamma-globulin (IVGG) in severe Guillain-Barré syndrome (GBS) in a small open study. Seven patients were given IVGG (0.4 g/kg/day) for 5 consecutive days. At the start of treatment all had progressing limb weakness and none could stand unaided. Within 24 h all but one patient started to improve, without the expected plateau phase, and progress was maintained with a mean time to independent walking of 14 days. One patient started treatment 9 h prior to ventilation for 15 days but was walking independently 31 days after admission. This study provides further evidence that IVGG is a promising therapeutic alternative to plasmapheresis in GBS. The rapidity of the response to IVGG raises the possibility that a single dose regimen might be equally or more effective.

Ecological and physiological analyses of Pseudomonad species within a phenol remediation system.

A diverse collection of 700 bacteria obtained from an operational phenolic remediating industrial treatment plant was made to select potential strains as microbial biosensors. Pseudomonads were the most abundant group, of which 48 selected from the liquor or suspended solids were assessed for their physiological response to phenolic pollutant loading and niche specialisation. By FAME-MIS identification the Pseudomonads were clustered into six major species groups. Those isolates able to utilise phenol as a sole carbon source predominantly belonged to a non-clonal Pseudomonas pseudoalcaligenes cluster determined by REP-PCR genotyping. Rapid microtitre based respiration assays were developed to contrast activity in response to increasing concentrations of phenol. A considerable range in response for both phenol degrader and non-degrader strains was observed. This natural phenotypic and physiological heterogeneity could facilitate the selection of isolates for the development of a suite of ecologically relevant, custom designed sensors with predictable toxicity susceptibilities to monitor process efficacy.

Chronic subgaleal haematoma.

A case is reported of a chronic subgaleal haematoma resulting from repeated head trauma during epileptic fits. The haematoma, which was organized and partially calcified, complicated the diagnosis and treatment of an underlying subdural haematoma.

Two-surgeon approach to thoracic outlet syndrome: long-term outcome.

An orthopaedic surgeon and a vascular surgeon jointly conducted 30 operations for thoracic outlet syndrome in 27 patients, having done the preoperative assessments in conjunction with a neurologist. Anterior scalenectomy was performed by the supraclavicular route except in one case where the infraclavicular route was used. The further surgical procedure was tailored to the abnormalities identified--i.e. resection of cervical rib or band, or medial scalenectomy. The first rib was spared. At median follow-up of 37 months (range 3-228) results were judged excellent or good on 26/30 sides (87%); on the three occasions when scalenectomy alone was performed, the results were only fair or poor. There were no major complications and no patient required reoperation. The long-term outcome in this series suggests that, with multidisciplinary assessment and two-surgeon operative treatment, good results can be obtained by the supraclavicular route without resection of the first rib.

[Influence of choline on amnesia in Alzheimer's disease (author's transl)]. / Action de la choline sur les troubles mnésiques de la maladie d'Alzeimer.

Eight patients with Alzheimer's disease presenting whith memory difficulties and no significant intellectual deterioration were treated with 9 grams daily. Choline base orally for 3 weeks. Quantitative testing, which evaluate memory capabilities such as learning and recall after delays of 1 hour and 24 hours, were used before and after the administration of Choline. The results of a global statistical analysis did not show any significant difference in the performances obtained before and after choline. However, in two patients, recall performance improvement was confirmed clinically. Most likely, these two patients were suffering from an mild foorm of Alzheimer's disease.