Environmental correlates of population differentiation in Atlantic herring

The marine environment is characterized by few physical barriers, and pelagic fishes commonly show high migratory potential and low, albeit in some cases statistically significant, levels of genetic divergence in neutral genetic marker analyses. However, it is not clear whether low levels of differentiation reflect spatially separated populations experiencing gene flow or shallow population histories coupled with limited random genetic drift in large, demographically isolated populations undergoing independent evolutionary processes. Using information for nine microsatellite loci in a total of 1951 fish, we analyzed genetic differentiation among Atlantic herring from eleven spawning locations distributed along a longitudinal gradient from the North Sea to the Western Baltic. Overall genetic differentiation was low (theta = 0.008) but statistically significant. The area is characterized by a dramatic shift in hydrography from the highly saline and temperature stable North Sea to the brackish Baltic Sea, where temperatures show high annual variation. We used two different methods, a novel computational geometric approach and partial Mantel correlation analysis coupled with detailed environmental information from spawning locations to show that patterns of reproductive isolation covaried with salinity differences among spawning locations, independent of their geographical distance. We show that reproductive isolation can be maintained in marine fish populations exhibiting substantial mixing during larval and adult life stages. Analyses incorporating genetic, spatial, and environmental parameters indicated that isolating mechanisms are associated with the specific salinity conditions on spawning locations.     

Urinary excretion of epsilondA is not predictive of cancer development: a prospective nested case-control study

Human biomonitoring of the lipid peroxidation DNA modification 1,N⁶-ethenodeoxyadenosine (εdA) excreted into urine is thought to be a potential marker for oxidative stress-related DNA damage and human cancer. We have tested this hypothesis in a prospective, nested case-control study. During the years 1984-1989, 24-h urines were collected from 1956 men in the Kuopio Ischaemic Heart Disease (KIHD) Risk Factor Study. εdA concentrations were measured by LC-MS/MS in 24-h urine samples from 47 men with cancer diagnosed at follow up until 2001 and from 31 cancer free smoking-matched control subjects. Odds ratio for having higher than control median εdA excretion rate and cancer, estimated by binary logistic regression, was 0.73 (95% CI 0.29-1.80, p=0.49). In this study, the urinary excretion of εdA provides no additional prediction of cancer development in males after controlling for smoking.     

Bodily illusions modulate tactile perception

Touch differs from other exteroceptive senses in that the body itself forms part of the tactile percept. Interactions between proprioception and touch provide a powerful way to investigate the implicit body representation underlying touch. Here, we demonstrate that an intrinsic primary quality of a tactile object, for example its size, is directly affected by the perceived size of the body part touching it. We elicited proprioceptive illusions that the left index finger was either elongating or shrinking by vibrating the biceps or triceps tendon of the right arm while subjects grasped the tip of their left index finger. Subjects estimated the distance between two simultaneous tactile contacts on the left finger during tendon vibration. We found that tactile distances feel bigger when the touched body part feels elongated. Control tests showed that the modulation of touch was linked to the perceived index-finger size induced by tendon vibration. Vibrations that did not produce proprioceptive illusion had no effect on touch. Our results show that the perception of tactile objects is referenced to an implicit body representation and that proprioception contributes to this body representation. We also provide, for the first time, a quantitative, implicit measure of distortions of body size.     

Community-based Monitoring of Natural Resource Use and Forest Quality in Montane Forests and Miombo Woodlands of Tanzania

A community-based monitoring system that focuses on natural resource use and forest quality in montane evergreen forest and miombo woodland areas was developed and implemented in 23 villages in 2002 as part of a participatory forest management regime in Iringa District, Tanzania. The scheme was developed to suit the needs and capacities of locally-elected natural resource committees managing and monitoring natural forests. Rather than measuring biodiversity, the monitoring is focused on resource extraction and disturbance. High levels of commitment to the monitoring were displayed by village level managers, and the preliminary feed-back indicates that the monitoring scheme provides them with the relevant information needed to suggest appropriate management interventions. While external support has been essential to cover development costs, natural resource revenue generated at village level can provide most of the running costs. Once developed, the scheme can, however, be transferred to similar areas at significantly lower costs that can be met by Tanzanian District budgets. Natural resource revenue generated from montane forests is generally much lower than in woodland areas due to restrictions on resource extraction imposed as a consequence of national and international interests. Opportunities to provide economic incentives for montane forest managers through direct utilisation of the resource are limited and it remains to be seen whether other non-economic incentives can sustain long term commitment in these biodiversity rich areas. Findings indicate that the key elements of this local resource utilisation monitoring scheme are simplicity, incentive mechanisms, transparency and accountability, and autonomy for local managers. However, the methods may not provide sufficient data on changes in biodiversity values in the high value forests and may need to be augmented by conventional monitoring by scientists funded by national or international institutions. Elements of the scheme are now being institutionalised within the forestry sector in Tanzania.     

Redox-responsive and calcium-dependent switching of glycosyldisulfide interactions with Concanavalin A

Glycosyldisulfides can interact efficiently with carbohydrate-binding entities. This has been shown for a range of thiosaccharide dimers when tested for their effects against the lectin Concanavalin A using a modified quartz crystal microbalance-technique. Contrary to the thiosaccharide monomers, showing no significant binding up to 10 mM, several of the dimers showed IC(50)-values in the low millimolar range. Three of the glycosyldisulfides tested also displayed very high positive apparent cooperativity effects that were found to be both calcium-dependent and redox-responsive.     

A rapid and efficient transformation protocol for the grass Brachypodium distachyon

A fast and efficient microprojectile bombardment-mediated transformation protocol is reported for the grass species Brachypodium distachyon, a proposed alternative model plant to Oryza sativa for functional genomics in grasses. Embryogenic calli derived from immature embryos were transformed by a construct containing the uidA (coding for beta-glucuronidase) and bar (coding for phosphinothricin acetyl transferase) genes, and bialaphos, a non-selective herbicide, was used as the selection agent throughout all phases of the tissue culture. Average transformation efficiencies of 5.3% were achieved, and for single bombardments transformation efficiencies of up to 14% were observed. The time frame from the bombardment of embryogenic callus to the harvesting of transgenic T1 seeds was 29 weeks and 25 weeks for the diploid and two tetraploid accessions used, respectively. Since the seed-to-seed life cycle is 19 weeks for the diploid and 15 weeks for the tetraploid accessions, our B. distachyon transformation system allows testing of both the T0 and the T1 generation as well as production of T2 seeds within 1 year.     

Phenotypic plasticity in <Emphasis Type="Italic">Carlina vulgaris</Emphasis>: effects of geographical origin,population size,and population isolation

If phenotypic plasticity is under genetic control, it may vary in amount and pattern on a geographical scale, e.g. among different regions of a species distribution. It may also differ between large and small or between less and more isolated populations, due to differences in genetic diversity. In a 2-year common garden study, the responses of several traits to drought and fertilizer treatments were studied in the grassland herb Carlina vulgaris. Individuals originating from populations of different size and degree of isolation in six European countries, representing central and marginal regions, were compared. Fertilizing had a negative effect on early plant survival, as well as on flowering probability in surviving plants. However, in those plants that flowered, fertilizing strongly increased mean number of flowerheads, flowerhead area (a correlate of seed number), and seed mass. Drought had generally weaker effects but enhanced survivorship, indicating that this treatment was closer to optimal conditions than were non-drought conditions. For some traits there were significant interactions of region × fertilizer, but the geographical pattern of reaction norms was inconsistent and lent no support to the hypothesis that central and marginal populations differ in overall plasticity. Population size and isolation had hardly any influence on treatment responses, but populations within regions differed in their mean response to fertilizing with regard to survival and flowering probabilities, as well as in their response to drought with regard to survival and total flowerhead area. It is concluded that response to raised nutrient levels is highly variable within populations, ranging from death to strongly increased reproductive output, but also among populations irrespective of size or isolation. This also goes for the response to water supply, though this variation shows a more unclear pattern. There is no evidence that small or isolated/marginal populations are less plastic than large or non-isolated/central populations, and the explanation for differences in treatment responses among plant populations should be sought in other population characteristics.     

Carbohydrate-active enzymes involved in the secondary cell wall biogenesis in hybrid aspen

Wood formation is a fundamental biological process with significant economic interest. While lignin biosynthesis is currently relatively well understood, the pathways leading to the synthesis of the key structural carbohydrates in wood fibers remain obscure. We have used a functional genomics approach to identify enzymes involved in carbohydrate biosynthesis and remodeling during xylem development in the hybrid aspen Populus tremula x tremuloides. Microarrays containing cDNA clones from different tissue-specific libraries were hybridized with probes obtained from narrow tissue sections prepared by cryosectioning of the developing xylem. Bioinformatic analyses using the sensitive tools developed for carbohydrate-active enzymes allowed the identification of 25 xylem-specific glycosyltransferases belonging to the Carbohydrate-Active EnZYme families GT2, GT8, GT14, GT31, GT43, GT47, and GT61 and nine glycosidases (or transglycosidases) belonging to the Carbohydrate-Active EnZYme families GH9, GH10, GH16, GH17, GH19, GH28, GH35, and GH51. While no genes encoding either polysaccharide lyases or carbohydrate esterases were found among the secondary wall-specific genes, one putative O-acetyltransferase was identified. These wood-specific enzyme genes constitute a valuable resource for future development of engineered fibers with improved performance in different applications.     

A dataset of human cornea proteins identified by Peptide mass fingerprinting and tandem mass spectrometry

Diseases of the cornea are extremely common and cause severe visual impairment worldwide. To explore the basic molecular mechanisms involved in corneal health and disease, the present study characterizes the proteome of the normal human cornea. All proteins were extracted from the central 7-mm region of 12 normal human donor corneas containing all layers: epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. Proteins were fractionated and identified using two different procedures: (i) two-dimensional gel electrophoresis and protein identification by MALDI-MS and (ii) strong cation exchange or one-dimensional SDS gel electrophoresis followed by LC-MS/MS. All together, 141 distinct proteins were identified of which 99 had not previously been identified in any mammalian corneas by direct protein identification methods. The characterized proteins are involved in many processes including antiangiogenesis, antimicrobial defense, protection from and transport of heme and iron, tissue protection against UV radiation and oxidative stress, cell metabolism, and maintenance of intracellular and extracellular structures and stability. This proteome study of the healthy human cornea provides a basis for further analysis of corneal diseases and the design of bioengineered corneas.