Growth patterns in young adult monozygotic twin pairs discordant and concordant for obesity.

Weight discordance is very rare in monozygotic (MZ) twin pairs; when found, however, such pairs are advantageous in the search for either environmental or epigenetic causes and consequences of obesity. We analyzed the growth patterns of young adult MZ pairs discordant and concordant for obesity. Screening 5 consecutive birth cohorts (1975-1979) of 22- to 27-year-old Finnish twins (the FinnTwin16 study), we found 14 obesity discordant (Body Mass Index [BMI] difference > or = 4 kg/m2) MZ pairs out of 658. Ten pairs participated in clinical studies. Nine concordant pairs (BMI difference < or = 2 kg/m2) were examined as controls. Lifetime measured heights and weights recorded in hospitals and health centers were traced manually. Height development was similar in all the co-twins of both groups. The weight differences between the co-twins of the discordant pairs began to emerge at 18 years leading to an average discordance of 16.4 kg, 5.6 kg/m2 (p for both = .005) at 25.7 years. The heavier co-twin weighed 221 g (p = .066), 1.0 kg/m2 (p = .01) more already at birth than the leaner, but the differences waned by 6 months of age and reappeared only after adolescence. Both the leaner and the heavier co-twins of the discordant pairs weighed more than expected by the singleton reference values (Cole et al., 1998) after 8 years. The concordant co-twins, on the other hand, grew similarly and after 6 months, their mean growth was not distinguishable from the singleton patterns. Young adulthood represents a critical period of gaining weight irrespective of genetic background in this twin sample.     

Cost-Effective Marine Protection - A Pragmatic Approach

This paper puts forward a framework for probabilistic and holistic cost-effectiveness analysis to provide support in selecting the least-cost set of measures to reach a multidimensional environmental objective. Following the principles of ecosystem-based management, the framework includes a flexible methodology for deriving and populating criteria for effectiveness and costs and analyzing complex ecological-economic trade-offs under uncertainty. The framework is applied in the development of the Finnish Programme of Measures (PoM) for reaching the targets of the EU Marine Strategy Framework Directive (MSFD). The numerical results demonstrate that substantial cost savings can be realized from careful consideration of the costs and multiple effects of management measures. If adopted, the proposed PoM would yield improvements in the state of the Baltic Sea, but the overall objective of the MSFD would not be reached by the target year of 2020; for various environmental and administrative reasons, it would take longer for most measures to take full effect.     

Environmental factors affecting the occurrence of different morphological forms of cyanoprokaryotes in the northern Baltic Sea

Cyanoprokaryotes (blue-green algae, cyanobacteria) and environmentalfactors were studied in the Baltic Sea, off the SW coast ofFinland, from April to December 1993. The aim was to outlinethe seasonal development of cyanoprokaryote populations andthe occurrence of species and species groups in relation toprevailing hydrographic conditions and general features of theplanktonic community. Altogether, 27 taxa of cyanoprokaryoteswere encountered, representing the orders Chroococcales, Nostocalesand Oscillatoriales. Different morphological forms of cyanoprokaryotespredominated during certain periods of the year the spherical,gomphosphaerioid colonies of the genera Coelomoron, Coelosphaerium,Snowella and Woronichinia were rather abundant in early springand the most abundant group in late autumn; minute-celled colonieswith mucilaginous structures, e.g. the genera Aphanothece, Cyanonephron,Lemmermanniella and Merismopedia, were abundant during earlysummer; and filamentous, nitrogen-fixing species in late summerand early autumn. Each of the periods represents a distinctsuccessional phase of the planktonic community with inherentenvironmental conditions, and it was obvious that the cyanoprokaryoticassemblage was modified by the general development of the planktoniccommunity. According to canonical correspondence analysis (CCA),temperature and the weight ratio of inorganic nitrogen to inorganicphosphorus were the most important factors explaining variationin the cyanoprokaryote assemblage.     

Colourful coexistence of red and green picocyanobacteria in lakes and seas

Hutchinson's paradox of the plankton inspired many studies on the mechanisms of species coexistence. Recent laboratory experiments showed that partitioning of white light allows stable coexistence of red and green picocyanobacteria. Here, we investigate to what extent these laboratory findings can be extrapolated to natural waters. We predict from a parameterized competition model that the underwater light colour of lakes and seas provides ample opportunities for coexistence of red and green phytoplankton species. To test this prediction, we sampled picocyanobacteria of 70 aquatic ecosystems, ranging from clear blue oceans to turbid brown peat lakes. As predicted, red picocyanobacteria dominated in clear waters, whereas green picocyanobacteria dominated in turbid waters. We found widespread coexistence of red and green picocyanobacteria in waters of intermediate turbidity. These field data support the hypothesis that niche differentiation along the light spectrum promotes phytoplankton biodiversity, thus providing a colourful solution to the paradox of the plankton.     

Responses of Baltic Sea ice and open-water natural bacterial communities to salinity change

To investigate the responses of Baltic Sea wintertime bacterial communities to changing salinity (5 to 26 practical salinity units), an experimental study was conducted. Bacterial communities of Baltic seawater and sea ice from a coastal site in southwest Finland were used in two batch culture experiments run for 17 or 18 days at 0 degrees C. Bacterial abundance, cell volume, and leucine and thymidine incorporation were measured during the experiments. The bacterial community structure was assessed using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified partial 16S rRNA genes with sequencing of DGGE bands from initial communities and communities of day 10 or 13 of the experiment. The sea ice-derived bacterial community was metabolically more active than the open-water community at the start of the experiment. Ice-derived bacterial communities were able to adapt to salinity change with smaller effects on physiology and community structure, whereas in the open-water bacterial communities, the bacterial cell volume evolution, bacterial abundance, and community structure responses indicated the presence of salinity stress. The closest relatives for all eight partial 16S rRNA gene sequences obtained were either organisms found in polar sea ice and other cold habitats or those found in summertime Baltic seawater. All sequences except one were associated with the alpha- and gamma-proteobacteria or the Cytophaga-Flavobacterium-Bacteroides group. The overall physiological and community structure responses were parallel in ice-derived and open-water bacterial assemblages, which points to a linkage between community structure and physiology. These results support previous assumptions of the role of salinity fluctuation as a major selective factor shaping the sea ice bacterial community structure.     

Cryopreservation of in vitro-grown shoot tips of raspberry (Rubus idaeus L.) by encapsulation–vitrification and encapsulation–dehydration

The first efficient cryopreservation procedure for in vitro-grown shoot tips of raspberry (Rubus idaeus L.) has been developed based on encapsulation–vitrification (EnVi) and encapsulation–dehydration (EnDe). EnVi resulted in higher survival (85%) and regrowth (75%) of cryopreserved shoot tips than EnDe (65 and 50%, respectively). In both cryogenic procedures, shoots regenerated from cryopreserved shoot tips without intermediary callus formation. Histological studies showed that a much larger number of meristematic cells survived following EnVi than EnDe. The EnVi procedure was applied to seven raspberry genotypes with an average survival and regrowth of 71 and 68%, respectively. Regenerated plants showed normal morphology. Results here indicate EnVi as a simple and efficient method for long-term preservation of R. idaeus germplasm.     

Accelerated In Vivo Proliferation of Memory Phenotype CD4+ T-cells in Human HIV-1 Infection Irrespective of Viral Chemokine Co-receptor Tropism

CD4⁺ T-cell loss is the hallmark of HIV-1 infection. CD4 counts fall more rapidly in advanced disease when CCR5-tropic viral strains tend to be replaced by X4-tropic viruses. We hypothesized: (i) that the early dominance of CCR5-tropic viruses results from faster turnover rates of CCR5⁺ cells, and (ii) that X4-tropic strains exert greater pathogenicity by preferentially increasing turnover rates within the CXCR4⁺ compartment. To test these hypotheses we measured in vivo turnover rates of CD4⁺ T-cell subpopulations sorted by chemokine receptor expression, using in vivo deuterium-glucose labeling. Deuterium enrichment was modeled to derive in vivo proliferation (p) and disappearance (d*) rates which were related to viral tropism data. 13 healthy controls and 13 treatment-naive HIV-1-infected subjects (CD4 143–569 cells/ul) participated. CCR5-expression defined a CD4⁺ subpopulation of predominantly CD45R0⁺ memory cells with accelerated in vivo proliferation (p = 2.50 vs 1.60%/d, CCR5⁺ vs CCR5⁻; healthy controls; P<0.01). Conversely, CXCR4 expression defined CD4⁺ T-cells (predominantly CD45RA⁺ naive cells) with low turnover rates. The dominant effect of HIV infection was accelerated turnover of CCR5⁺CD45R0⁺CD4⁺ memory T-cells (p = 5.16 vs 2.50%/d, HIV vs controls; P<0.05), naïve cells being relatively unaffected. Similar patterns were observed whether the dominant circulating HIV-1 strain was R5-tropic (n = 9) or X4-tropic (n = 4). Although numbers were small, X4-tropic viruses did not appear to specifically drive turnover of CXCR4-expressing cells (p = 0.54 vs 0.72 vs 0.44%/d in control, R5-tropic, and X4-tropic groups respectively). Our data are most consistent with models in which CD4⁺ T-cell loss is primarily driven by non-specific immune activation.     

Kelp flies and species concepts – the case of Coelopa frigida (Fabricius, 1805) and C. nebularum Aldrich, 1929 (Diptera: Coelopidae)

The beaches of the North Atlantic and North Pacific are home to kelp flies of the Coelopa frigida/nebularum complex, which consists of one to three different species depending on whether the two nominal species are accepted and a cryptic species proposed by Remmert is counted. The morphological differences between two populations of C. frigida ( Fabricius, 1805 ) from the North Sea and the Baltic Region and two populations of C. nebularum Aldrich, 1929 from Alaska and Japan are described and discussed for small, medium, and large specimens. Crossing experiments are used to demonstrate that, under laboratory conditions, no isolation mechanisms between either population exist. Coelopa frigida and C. nebularum are therefore regarded as a single biological species, a conclusion that is congruent with the observation that the genetic distances based on Ef 1‐α and 16S rDNA indicate lower levels of differentiation within C. frigida/nebularum than between undisputed Coelopa species. The substantial morphological, breeding and genetic information on the C. frigida/nebularum species complex is then applied to six different species concepts popular in the modern systematic literature. According to the Biological, Hennigian and Recognition Species Concepts, only a single species would be recognized. The Evolutionary Species Concept is too vague to be applicable and under two variants of the Phylogenetic Species Concept, C. frigida and C. nebularum would constitute separate species. This result confirms that Phylogenetic Species Concepts lead to a higher species number than concepts based on reproductive isolation. Practical and theoretical problems with the various species concepts are briefly discussed.