Synthesis of modified nucleosides for incorporation of formyletheno and carboxyetheno adducts of adenine nucleosides into oligonucleotides

Three protected derivatives of 1,N(6)-ethenoadenine nucleosides, viz. 3-[5-O-(4,4'-dimethoxytrityl) of 7-formyl-(1) and 7-(1,2-diacetyloxypropyl)-2'-deoxyadenosine (2), and 3-[5-O-(4,4'-dimethoxytrityl)-2-O-(tert-butyldimethylsilyl)-7-(ethoxycarbonyl)adenosine (3), expected to allow introduction of formyletheno and carboxyethenoadenine adducts into oligonucleotides by the conventional phosphoramidite chemistry, have been synthesized.     

Models relating stem growth to crown length dynamics: application to loblolly pine and Norway spruce

We derive and analyze a model that relates the growth rate of cross-sectional area (‘csa’) at any height on the central stem of a tree to crown-length dynamics. The derivation is based, in part, on assumptions that (a) active csa on the central stem relates allometrically to the length of crown above the cross section, and (b) inactive csa is proportional to active csa within the crown. We also assume that the deactivation rate of csa beneath the crown is determined, in part, by the rate of crown rise. Integration of the growth-rate model under an additional assumption—that total crown length is constant after stand closure—provides a simple model of annual or periodic growth of total csa that can be fit to standard growth data. Three implications of the assumptions and integration are notable: (1) total csa within the crown scales allometrically with stem length above the cross section; (2) for a special case, total csa beneath the crown scales with stem length above the cross section; more generally, csa scales with a linear combination of the stem and crown lengths; and (3) the stem beneath the crown forms to approximate a frustum of a quadratic paraboloid. Basal area data from a loblolly pine (Pinus taeda L.) spacing trial show good agreement with (1) and (2), and with an empirical model developed from the special case of (2). Data from the plots of a Norway spruce (Picea abies (L.) Karst.) thinning trial, where crown length remained approximately constant, show good agreement with (2) and the empirical model. Prediction (3) is demonstrated by simulation.     

Moose and vole browsing patterns in experimentally assembled pure and mixed forest stands

Plants growing in diverse communities are believed to exhibit associational resistance to herbivores, but this hypothesis has seldom been tested experimentally for vertebrate herbivores in forest ecosystems. We examined browsing patterns of the two principal mammalian herbivores of Finnish boreal forests, moose and voles, in young stands where tree species diversity and composition were experimentally manipulated. The stands were composed either of monocultures or different 2–5 species mixtures of Norway spruce, Scots pine, Siberian larch, silver birch, and black alder. Voles and moose showed contrasting responses to stand diversity and species composition. In accordance with the predictions of the associational resistance hypothesis, vole damage was higher in tree monocultures than in mixed stands, although stand diversity effects were statistically significant only at one of the three study areas. Voles also damaged more trees in coniferous than in deciduous stands. In contrast, moose browsing tended to increase with the number of tree species in a stand and with the presence of the preferred tree species, birch, in a mixture. The observed differences in vole and moose responses to stand diversity and species composition are likely to be due to different feeding specialisation, foraging patterns, and movement ability of these herbivores. Voles switched to trees only when the supply of a more preferred food (grasses and forbs) was depleted and restricted their feeding choice only to the most palatable tree species regardless of the number of tree species present per stand. In contrast, tree branches and foliage represented an important part of moose diet throughout the year; moose may be able to tolerate secondary plant metabolites of different tree species better than voles and may thus benefit from diet broadening when more tree species are available. Furthermore, the home range size and foraging ability of these two very differently sized herbivores may partly explain the observed differences in utilisation of different tree species. Finally, both moose and voles showed high spatial and temporal variation in their feeding; in particular, vole damage was more influenced by tree species diversity in areas and years with high vole densities. Thus, diversification of forest stands may have very different effects on mammalian browsing depending on the herbivores present, their densities, and the tree species used in reforestation.     

Solution structures of the first and fourth TSR domains of F-spondin

F-spondin is a protein mainly associated with neuronal development. It attaches to the extracellular matrix and acts in the axon guidance of the developing nervous system. F-spondin consists of eight domains, six of which are TSR domains. The TSR domain family binds a wide range of targets. Here we present the NMR solution structures of TSR1 and TSR4. TSR domains have an unusual fold that is characterized by a long, nonglobular shape, consisting of two beta-strands and one irregular extended strand. Three disulfide bridges and stack of alternating tryptophan and arginine side-chains stabilize the structure. TSR1 and TSR4 structures are similar to each other and to the previously determined TSR domain X-ray structures from another protein, TSP, although TSR4 exhibits a mobile loop not seen in other structures.     

Nitrogen retention by peatland buffer areas at six forested catchments in southern and central Finland

We studied the nitrogen retention capacity of six peatland buffer areas constructed in forested catchments in southern and central Finland. The buffers (0.1–4.9% of the total catchment area) were either undrained mires or drained peatlands rewetted 4–7 years before the present study. The N retention capacity was studied by adding ammonium nitrate (NH₄NO₃–N) solution into the inflow waters of the buffers once (one area) or twice (five areas) during a period of 4–6 years. Except for the first N addition in one area, the three largest buffer areas (relative size > 1%) retained the added inorganic N almost completely; their retention efficiencies during the year of addition were >93% for both NO₃–N and NH₄–N. Two of the three small buffers (relative size < 0.25%) were also able to reduce inorganic N from the through-flow waters effectively; their retention capacities for inorganic nitrogen varied between 58 and 89%. However, one small buffer area had a retention capacity of only <20%. The factors contributing to efficient N retention were hydrological load during N addition, relative size of the buffer area, and its length, i.e. the distance between the inflow and outflow points. If there was any release of the added N, it mostly occurred within a relatively short-time period (<100 days) after the treatment. The buffer areas appeared to be efficient and long-term sinks for inorganic nitrogen because the release of N during the 2–4 years after N addition was minor.     

Androgen receptors and testosterone in men--effects of protein ingestion, resistance exercise and fiber type

The purpose of this study was to examine the impact of protein ingestion on circulating testosterone and muscle androgen receptor (AR) as well as on insulin-like growth factor-I (MGF and IGF-IEa) responses to a resistance exercise (RE) bout in (57-72 year) men. Protein (15 g whey) (n=9) or placebo (n=9) was consumed before and after a RE bout (5 sets of 10 repetition maximums), and vastus lateralis muscle biopsies were taken pre, 1 and 48 h post-RE. The protein ingestion blunted the RE-induced increase in serum free and total testosterone while the RE bout significantly increased muscle AR mRNA levels in older men (P<0.05). However, protein ingestion did not significantly affect AR mRNA or protein expression, or MGF and IGF-IEa mRNA expression at 1 and 48 h post-RE. Immunohistochemical staining of muscle cross-sections was done with antibodies specific to AR and MyHC I and II and showed that there seems to be within or near the type-I muscle fibers a greater staining of ARs than within or near the type-II fibres. In conclusion, the protein ingestion hinders RE-induced increase in serum testosterone in older men but may not significantly affect muscle AR, MGF or IGF-IEa gene expression. Furthermore, the present study shows that even older men are able to increase muscle AR mRNA expression in response to a RE bout.     

Solution structure of the first immunoglobulin domain of human myotilin

Myotilin is a 57 kDa actin-binding and -bundling protein that consists of a unique serine-rich amino-terminus, two Ig-domains and a short carboxy-terminus with a PDZ-binding motif. Myotilin localizes in sarcomeric Z-discs, where it interacts with several sarcomeric proteins. Point mutations in myotilin cause muscle disorders morphologically highlighted by sarcomeric disarray and aggregation. The actin-binding and dimerization propensity of myotilin has been mapped to the Ig-domains. Here we present high-resolution structure of the first Ig-domain of myotilin (MyoIg1) determined with solution state NMR spectroscopy. Nearly complete chemical shift assignments of MyoIg1 were achieved despite several missing backbone ¹H-¹⁵N-HSQC signals. The structure derived from distance and dihedral angle restraints using torsion angle dynamics was further refined using molecular dynamics. The structure of MyoIg1 exhibits I-type Ig-fold. The absence of several backbone ¹H-¹⁵N-HSQC signals can be explained by conformational exchange taking place at the hydrophobic core of the protein. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.