Intraspecific genetic variation of a Fagus sylvatica population in a temperate forest derived from airborne imaging spectroscopy time series

1. The growing pace of environmental change has increased the need for large‐scale monitoring of biodiversity. Declining intraspecific genetic variation is likely a critical factor in biodiversity loss, but is especially difficult to monitor: assessments of genetic variation are commonly based on measuring allele pools, which requires sampling of individuals and extensive sample processing, limiting spatial coverage. Alternatively, imaging spectroscopy data from remote platforms may hold the potential to reveal genetic structure of populations. In this study, we investigated how differences detected in an airborne imaging spectroscopy time series correspond to genetic variation within a population of Fagus sylvatica under natural conditions.
2. We used multi‐annual APEX (Airborne Prism Experiment) imaging spectrometer data from a temperate forest located in the Swiss midlands (Laegern, 47°28'N, 8°21'E), along with microsatellite data from F. sylvatica individuals collected at the site. We identified variation in foliar reflectance independent of annual and seasonal changes which we hypothesize is more likely to correspond to stable genetic differences. We established a direct connection between the spectroscopy and genetics data by using partial least squares (PLS) regression to predict the probability of belonging to a genetic cluster from spectral data.
3. We achieved the best genetic structure prediction by using derivatives of reflectance and a subset of wavebands rather than full‐analyzed spectra. Our model indicates that spectral regions related to leaf water content, phenols, pigments, and wax composition contribute most to the ability of this approach to predict genetic structure of F. sylvatica population in natural conditions.
4. This study advances the use of airborne imaging spectroscopy to assess tree genetic diversity at canopy level under natural conditions, which could overcome current spatiotemporal limitations on monitoring, understanding, and preventing genetic biodiversity loss imposed by requirements for extensive in situ sampling.

     

Spinal Loads during Cycling on an Ergometer

Cycling on an ergometer is an effective exercise for improving fitness. However, people with back problems or previous spinal surgery are often not aware of whether cycling could be harmful for them. To date, little information exists about spinal loads during cycling. A telemeterized vertebral body replacement allows in vivo measurement of implant loads during the activities of daily living. Five patients with a severe compression fracture of a lumbar vertebral body received these implants. During one measurement session, four of the participants exercised on a bicycle ergometer at various power levels. As the power level increased, the maximum resultant force and the difference between the maximum and minimum force (force range) during each pedal revolution increased. The average maximum-force increases between the two power levels 25 and 85 W were 73, 84, 225 and 75 N for the four patients. The corresponding increases in the force range during a pedal revolution were 84, 98, 166 and 101 N. There were large variations in the measured forces between the patients and also within the same patient, especially for high power levels. In two patients, the maximum forces during high-power cycling were higher than the forces during walking measured on the same day. Therefore, the authors conclude that patients with back problems should not cycle at high power levels shortly after surgery as a precaution.     

Differential inhibition of glutamine and gamma-glutamylcysteine synthetases by alpha-alkyl analogs of methionine sulfoximine that induce convulsions.

The alpha-methyl and alpha-ethyl analogs of methionine sulfoximine, like methionine sulfoximine, induce convulsions in mice and inhibit glutamine synthetase irreversibly; alpha-ethylmethionine sulfoximine is approximately 50% as inhibitory as methionine sulfoximine and alpha-methylmethionine sulfoximine. However, whereas alpha-methylmethionine sulfoximine and methionine sulfoximine inhibit gamma-glutamylcysteine synthetase markedly, alpha-ethylmethionine sulfoximine does not, nor does administration of the alpha-ethyl analog produce the decrease in tissue glutathione levels found after giving methionine sulfoximine or its alpha-methyl analog. The findings strongly indicate that methionine sulfoximine-induced convulsions are closely associated with inhibition of glutamine synthetase rather than with inhibition of gamma-glutamylcysteine synthetase. The alpha-alkyl methionine sulfoximine analogs cannot be catabolized via the corresponding alpha-keto or alpha-imino acids, and, like other alpha-substituted amino acids, are probably not metabolized to a significant extent in vivo; this suggests that the amino acid sulfoximine molecules themselves, rather than their metabolites, are directly involved in the induction of convulsions. Possible explanations for the reported lack of correlation between the occurrence of convulsions and the levels of glutamine synthetase activity (and its substrates and product) are considered. The findings suggest that studies on the mechanism of induction of convulsions may be extended significantly and refined in biochemical terms by the use of other structurally modified convulsant molecules.     

Comparison of the serum selenium content of healthy adults living in the Antwerp region (Belgium) with recent literature data.

Graphite furnace atomic absorption spectrometry, after improved matrix modification and using Zeeman background correction, was used to measure the serum selenium content of healthy adults living in the Antwerp region (Belgium). The mean serum concentration of 13 men and 13 women, sampled once a month during 1 year, was 84.3 +/- 9.4ng/ml with a broad range of 51.4-121.7 ng/ml. The intra-individual variation was remarkably high. Recent literature on selenium concentrations is reviewed and values are tabulated, with limitation to healthy adults and European countries. The mean serum selenium concentration measured corresponded well to older literature data for Belgium. The obtained values were found to be in the medium range compared with the literature data for other European countries.     

Fluorescence characteristics of cyanobacteria (blue-green algae)

The fluorescence characteristics of the cyanobacteria Synechocystisaquatilis Sauv., Microcystis firma (Breb. et Lenorm.) Schmidleand Synechococcus leopoliensis (Racib.) Kom. and the green algaScenedesmus quadricauda (Turp.) Breb. were examined. In thethree cyanobacteria, phycocyanin is the main accessory pigment.Phycoerythrin is not present in our investigated strains ofcyanobacteria. The highest excitation of the chlorophyll a (Chla) fluorescence of cyanobacteria resulted from light with wavelengthsof 620–630 nm. A definite ‘Kautsky’ effectis also evident at this wavelength. However, excitation withblue light (420–520 nm) produced only very slight fluorescence.The Kautsky effect is not evident at these wavelengths, evenat high photon flux densities. For Scenedesmus, fluorescencecharacteristics typical of green algae were found. The fluorescenceexcitation of cyanobacteria at 620 nm corresponds to a photosynthesispeak in the action spectrum measured in terms of O₂ production.The results underline the necessity of fluorescence measurementsat several wavelengths whenever mixed populations are involved.Such measurements also present possibilities for more accurateestimation of biomass and potential photosynthetic productionin mixed populations.     

Electrotransformation of intact and osmotically sensitive cells of Corynebacterium glutamicum

Summary Intact and osmotically sensitive cells of Corynebacterium glutamicum can be efficiently transformed by electroporation. This was shown by using the plasmid vector pUL-330 (5.2 kb), containing the kanamycin resistance gene of transposon Tn5. The following electric parameters yielded efficient transformation. For intact cells: one exponentially decaying field pulse with time constants and with initial field intensities of E ₀=35–40 kV cm^-1; prepulse temperature 20°C. Cell regeneration (survival) was 100%–80%. Transformation efficiency can be increased by an additional freeze and thaw cycle of the cells, prior to electroporation. Lysozyme treated cells (osmotically sensitive) were transformed with three successive pulses of E ₀=25–30 kV cm^-1. Cell regeneration under these conditions was found to be 20–30%. The optimum yield of transformants/g plasmid-DNA was 3×10³ for intact cells, 2×10⁴ for intact cells which were frozen and thawed twice and 7×10⁴ for osmotically sensitive cells if the cell suspension was pulsed at a cell density of 1–3×10⁸/ml and at a DNA concentration of 0.2 g/ml up to 2 g/ml. The data obtained for osmotically sensitive cells suggest that the temperature increase accompanying the electric field pulse enhances colony formation and transformation efficiency if the initial prepulse temperature is 20°C, although regeneration of electroporated C. glutamicum cells starts to decrease at temperatures20°C.     

Changes in auditory evoked brain potentials during ultra-low frequency whole-body vibration of man or of his visual surround

Auditory evoked brain potentials (AEP) were recorded from nine healthy male subjects during three types of condition: A - subject and visual field stationary; B - subject vibrated (z-axis, 0.6 Hz, 1.85 ms-2 rms), visual field stationary; C - subject stationary, visual field vibrated (as for B). The visual surround was confined to a checkerboard pattern in front of the subject. Auditory stimuli (1000 Hz, 86 dB, interstimulus interval 7 s) were delivered via headphones to evoke AEP. Vibration-synchronous activity in the EEG was eliminated by a subtraction technique. In comparison with condition A, conditions B and C caused an attenuation of P2 and N1P2 components of AEP together with an increased latency of N1. Effects of conditions B and C did not differ. Direct vestibular stimulation and mechanisms specific for whole-body vibration were rejected as modes of action. The AEP-changes and the subjective evaluation of experimental conditions, arousal and performance, as well as symptoms of kinetosis (motion sickness) suggest a sensory mismatch, leading to a "latent kinetosis" with de-arousal, as the dominating mechanism by which the processing of information was affected. This suggestion was supported by an additional pilot study. Under real working conditions a similar effect can be expected during relative motion between the driver and his visual surround, i.e. even with perfect vibro-isolation of the driver's seat.     

Protection against cisplatin toxicity by administration of glutathione ester

The role of cellular glutathione in the prevention of toxicity due to the anti-cancer drug cisplatin (cis-diamminedichloroplatinum) was explored in mice treated with buthionine sulfoximine (BSO), a selective inhibitor of gamma-glutamylcysteine synthetase (and therefore of glutathione synthesis), and with glutathione and glutathione monoisopropyl ester. Pretreatment of mice with BSO enhanced the lethal toxicity of cisplatin by about twofold. Administration of glutathione ester (dose, 2.5-7.5 mmol/kg) protected against lethal cisplatin toxicity; glutathione was also effective, but much less so. Glutathione ester, in contrast to glutathione, is effectively transported into cells and split to glutathione intracellularly. The previous findings that administered glutathione does not protect against lethal toxicity due to cadmium ions and mercuric ions, whereas glutathione ester does, suggest that intracellular glutathione is required for protection against these heavy metal ions. That administration of glutathione has a protective effect on cisplatin toxicity suggests that the toxic effects of cisplatin may be exerted both intracellularly and extracellularly, and that extracellular glutathione (or its degradation products) may form a complex with cisplatin extracellularly. The finding that glutathione ester is more effective than glutathione in protecting against the toxicity of cisplatin suggests that use of glutathione ester may be therapeutically advantageous.