Patterns in genetic diversity of Trifolium pallescens populations do not reflect chronosequence on alpine glacier forelands

How does genetic diversity within populations of plants develop during primary succession on alpine glacier forelands? Theory predicts that pioneer populations are characterized by low genetic diversity due to founder effects and that genetic diversity increases within populations as they mature and recurrent gene flow occurs. However, few genetic studies have so far been carried out on plants on glacier forelands. In this study, we analysed the development of genetic diversity with time for populations of Trifolium pallescens along successional series (chronosequences) on three parallel glacier forelands in the European Alps, using neutral amplified fragment length polymorphism. No general trend in the development of genetic diversity was observed with increasing population age: even pioneer populations harboured substantial genetic diversity. Assignment tests showed that the latter consist of a genetic sub-sample from several source areas, and not just from other populations on the glacier forelands. We also detected some long distances-that is, inter-valley gene flow events. However, gene flow was not spatially unrestricted, as shown by a weak isolation by distance pattern within glacier valleys. The actual patterns of genetic diversity along the chronosequences are a result of the combination of factors, such as gene flow and growth rate, influenced by site- and species-specific attributes.     

Colour-assortative mating among populations of Tropheus moorii, a cichlid fish from Lake Tanganyika, East Africa

The species flocks of cichlid fishes in the East African Lakes Tanganyika, Malawi and Victoria are prime examples of adaptive radiation and explosive speciation. Several hundreds of endemic species have evolved in each of the lakes over the past several thousands to a few millions years. Sexual selection via colour-assortative mating has often been proposed as a probable causal factor for initiating and maintaining reproductive isolation. Here, we report the consequences of human-mediated admixis among differentially coloured populations of the endemic cichlid fish Tropheus moorii from several localities that have accidentally been put in sympatry in a small harbour bay in the very south of Lake Tanganyika. We analysed the phenotypes (coloration) and genotypes (mitochondrial control region and five microsatellite loci) of almost 500 individuals, sampled over 3 consecutive years. Maximum-likelihood-based parenthood analyses and Bayesian inference of population structure revealed that significantly more juveniles are the product of within-colour-morph matings than could be expected under the assumption of random mating. Our results clearly indicate a marked degree of assortative mating with respect to the different colour morphs. Therefore, we postulate that sexual selection based on social interactions and female mate choice has played an important role in the formation and maintenance of the different colour morphs in Tropheus, and is probably common in other maternally mouthbrooding cichlids as well.     

Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans

Endurance and strength training are established as distinct exercise modalities, increasing either mitochondrial density or myofibrillar units. Recent research, however, suggests that mitochondrial biogenesis is stimulated by both training modalities. To test the training "specificity" hypothesis, mitochondrial respiration was studied in permeabilized muscle fibers from 25 sedentary adults after endurance (ET) or strength training (ST) in normoxia or hypoxia [fraction of inspired oxygen (Fi(O(2))) = 21% or 13.5%]. Biopsies were taken from the musculus vastus lateralis, and cycle-ergometric incremental maximum oxygen uptake (VO(2max)) exercise tests were performed under normoxia, before and after the 10-wk training program. The main finding was a significant increase (P < 0.05) of fatty acid oxidation capacity per muscle mass, after endurance and strength training under normoxia [2.6- and 2.4-fold for endurance training normoxia group (ET(N)) and strength training normoxia group (ST(N)); n = 8 and 3] and hypoxia [2.0-fold for the endurance training hypoxia group (ET(H)) and strength training hypoxia group (ST(H)); n = 7 and 7], and higher coupling control of oxidative phosphorylation. The enhanced lipid oxidative phosphorylation (OXPHOS) capacity was mainly (87%) due to qualitative mitochondrial changes increasing the relative capacity for fatty acid oxidation (P < 0.01). Mitochondrial tissue-density contributed to a smaller extent (13%), reflected by the gain in muscle mass-specific respiratory capacity with a physiological substrate cocktail (glutamate, malate, succinate, and octanoylcarnitine). No significant increase was observed in mitochondrial DNA (mtDNA) content. Physiological OXPHOS capacity increased significantly in ET(N) (P < 0.01), with the same trend in ET(H) and ST(H) (P < 0.1). The limitation of flux by the phosphorylation system was diminished after training. Importantly, key mitochondrial adaptations were similar after endurance and strength training, regardless of normoxic or hypoxic exercise. The transition from a sedentary to an active lifestyle induced muscular changes of mitochondrial quality representative of mitochondrial health.     

Tissue Quality Assessment Using a Novel Direct Elasticity Assessment Device (The E-Finger): A Cadaveric Study of Prostatectomy Dissection

Introduction

Minimally invasive radical prostatectomy (RP) (robotic and laparoscopic), have brought improvements in the outcomes of RP due to improved views and increased degrees of freedom of surgical devices. Robotic and laparoscopic surgeries do not incorporate haptic feedback, which may result in complications secondary to inadequate tissue dissection (causing positive surgical margins, rhabdosphincter damage, etc). We developed a micro-engineered device (6 mm² sized) [E-finger]) capable of quantitative elasticity assessment, with amplitude ratio, mean ratio and phase lag representing this. The aim was to assess the utility of the device in differentiating peri-prostatic tissue types in order to guide prostate dissection.

Material and Methods

Two embalmed and 2 fresh frozen cadavers were used in the study. Baseline elasticity values were assessed in bladder, prostate and rhabdosphincter of pre-dissected embalmed cadavers using the micro-engineered device. A measurement grid was created to span from the bladder, across the prostate and onto the rhabdosphincter of fresh frozen cadavers to enable a systematic quantitative elasticity assessment of the entire area by 2 independent assessors. Tissue was sectioned along each row of elasticity measurement points, and stained with haematoxylin and eosin (H&E). Image analysis was performed with Image Pro Premier to determine the histology at each measurement point.

Results

Statistically significant differences in elasticity were identified between bladder, prostate and sphincter in both embalmed and fresh frozen cadavers (p = <0.001). Intra-class correlation (ICC) reliability tests showed good reliability (average ICC = 0.851). Sensitivity and specificity for tissue identification was 77% and 70% respectively to a resolution of 6 mm².

Conclusions

This cadaveric study has evaluated the ability of our elasticity assessment device to differentiate bladder, prostate and rhabdosphincter to a resolution of 6 mm². The results provide useful data for which to continue to examine the use of elasticity assessment devices for tissue quality assessment with the aim of giving haptic feedback to surgeons performing complex surgery.     

Molecular phylogeny and population structure of the codling moth (Cydia pomonella) in Central Europe: II. AFLP analysis reflects human-aided local adaptation of a global pest species

Originally resident in southeastern Europe, the codling moth (Cydia pomonella L.) (Tortricidae) has achieved a nearly global distribution, being one of the most successful pest insect species known today. As shown in our accompanying study, mitochondrial genetic markers suggest a Pleistocenic splitting of Cydia pomonella into two refugial clades which came into secondary contact after de-glaciation. The actual distribution pattern shows, however, that Central European codling moths have experienced a geographic splitting into many strains and locally adapted populations, which is not reflected by their mitochondrial haplotype distribution. We therefore have applied, in addition to mitochondrial markers, an approach with a higher resolution potential at the population level, based on the analysis of amplification fragment length polymorphisms (AFLPs). As shown in the present study, AFLP markers elucidate the genetic structure of codling moth strains and populations from different Central European apple orchard sites. While individual genetic diversity within codling moth strains and populations was small, a high degree of genetic differentiation was observed between the analyzed strains and populations, even at a small geographic scale. One of the main factors contributing to local differentiation may be limited gene flow among adjacent codling moth populations. In addition, microclimatic, ecological, and geographic constraints also may favour the splitting of Cydia pomonella into many local populations. Lastly, codling moths in Central European fruit orchards may experience considerable selective pressure due to pest control activities. As a consequence of all these selective forces, today in Central Europe we see a patchy distribution of many locally adapted codling moth populations, each of them having its own genetic fingerprint. Because of the complete absence of any correlation between insecticide resistance and geographic or genetic distances among populations, AFLP markers do not have a prognostic value for predicting an outbreak of pesticide resistance in the field. By combining mitochondrial genetic data and AFLP analysis it was possible, however, to track the recent evolutionary history of Cydia pomonella on three different time scales: from population splitting in Pleistocene, to interbreeding of mitochondrial haplotypes in Holocene, to human-aided complete intermixing and splitting into many locally adapted populations in very recent times. The case of Cydia pomonella is reminiscent of examples of sympatric speciation and another example of a human-induced globally successful pest species.     

Design, construction, and use of an electroporator for plant protoplasts and animal cells

We have designed and constructed an electroporation device capable of efficient transfer of DNA into both plant cell protoplasts and cultured murine lymphocytes. The electroporator design allows various combinations of voltage and capacitance to be used to optimize the electric pulse. Switching of large voltages and currents is accomplished with a silicon-controlled rectifier, yielding excellent reproducibility and long component life. A safety switch is provided to permit complete discharge of the device. Conditions suitable for high levels of transient expression and high frequencies of stable transformation for both plant and animal cell systems have been found.     

Evaluation of DNA Variants Associated with Androgenetic Alopecia and Their Potential to Predict Male Pattern Baldness

Androgenetic alopecia, known in men as male pattern baldness (MPB), is a very conspicuous condition that is particularly frequent among European men and thus contributes markedly to variation in physical appearance traits amongst Europeans. Recent studies have revealed multiple genes and polymorphisms to be associated with susceptibility to MPB. In this study, 50 candidate SNPs for androgenetic alopecia were analyzed in order to verify their potential to predict MPB. Significant associations were confirmed for 29 SNPs from chromosomes X, 1, 5, 7, 18 and 20. A simple 5-SNP prediction model and an extended 20-SNP model were developed based on a discovery panel of 305 males from various European populations fitting one of two distinct phenotype categories. The first category consisted of men below 50 years of age with significant baldness and the second; men aged 50 years or older lacking baldness. The simple model comprised the five best predictors: rs5919324 near AR, rs1998076 in the 20p11 region, rs929626 in EBF1, rs12565727 in TARDBP and rs756853 in HDAC9. The extended prediction model added 15 SNPs from five genomic regions that improved overall prevalence-adjusted predictive accuracy measured by area under the receiver characteristic operating curve (AUC). Both models were evaluated for predictive accuracy using a test set of 300 males reflecting the general European population. Applying a 65% probability threshold, high prediction sensitivity of 87.1% but low specificity of 42.4% was obtained in men aged <50 years. In men aged ≥50, prediction sensitivity was slightly lower at 67.7% while specificity reached 90%. Overall, the AUC=0.761 calculated for men at or above 50 years of age indicates these SNPs offer considerable potential for the application of genetic tests to predict MPB patterns, adding a highly informative predictive system to the emerging field of forensic analysis of externally visible characteristics.     

Shifts of bacteriochlorophyll and carotenoid absorption bands linked to cytochrome c-555 photooxidation in Chromatium

Shifts in the absorption bands of bacteriochlorophyll and carotenoids in Chromatium vinosum chromatophores were measured after short actinic flashes, under various conditions. The amplitude of the bacteriochlorophyll band shift correlated well with the amount of cytochrome c-555 that was oxidized by P₈₇₀⁺ after a flash. No bacteriochlorophyll band shift appeared to accompany the photooxidation of P₈₇₀ itself, nor the oxidation of cytochrome c-552 by P₈₇₀⁺. The carotenoid band shift also correlated with cytochrome c-555 photooxidation, although a comparatively small carotenoid shift did occur at high redox potentials that permitted only P₈₇₀ oxidation.

The results explain earlier observations on infrared absorbance changes that had suggested the existence of two different photochemical systems in Chromatium. A single photochemical system accounts for all of the absorbance changes.

Previous work has shown that the photooxidations of P₈₇₀ and cytochrome c-555 cause similar changes in the electrical charge on the chromatophore membrane. The specific association of the band shifts with cytochrome c-555 photooxidation therefore argues against interpretations of the band shifts based on a light-induced membrane potential.     

First evidence of mtDNA sequence differences between Northern Bald Ibises (Geronticus eremita) of Moroccan and Turkish origin

Summary We examined two segments of the mitochondrial genome of Moroccan and Turkish Bald Ibises. One point mutation was consistently discovered in a 307 bp portion of the cytochrome b gene which was population specific. This is the first indication of a genetic differentiation between the two populations. The consequences of this finding for the conservation of the highly endangered bird are discussed. In future captive breeding and releasing programmes, only birds of known origin should be used.

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Erster Nachweis von Sequenzunterschieden in der mtDNS zwischen marokkanischen und türkischen Waldrappen (Geronticus eremita)

Zusammenfassung Bei der Untersuchung von zwei Segmenten der mitochondrialen DNS marokkanischer und türkischer Waldrappe konnten wir eine Punktmutation in einem 307 bp langen Abschnitt des Cytochrom b-Gens feststellen. Dies ist der erste Hinweis auf eine genetische Differenzierung zwischen den beiden Populationen. Die Konsequenzen der Ergebnisse für den Schutz dieser stark bedrohten Vogelart werden diskutiert. Bei Zucht- und Auswilderungsprogrammen muss die Herkunft der Tiere zukünftig unbedingt berücksichtigt werden.

     

Active analog pipeline delays for high signal rates in multistation flow cytometers

Flow cytometers with sequential measuring stations require alignment of event timing information to assure that multiparameter data for each cell are properly correlated. Information from the first detector must be delayed until signals are produced at the last detector, with adjustments to align them in time for simultaneous digitization after the last measurement is completed. By using an analog "pipeline" delay, the deadtime between the first and last measuring stations can be minimized. The described device is capable of acquiring and propagating many signals within the delay period, with good fidelity at high signal rates. An integrated circuit charge-coupled device (CCD), which is an analog shift register, is shown to be useful as a signal delay in the time range from 22 microseconds to several milliseconds.