Co‐occurrence patterns of trees along macro‐climatic gradients and their potential influence on the present and future distribution of Fagus sylvatica L.

Aim During recent and future climate change, shifts in large‐scale species ranges are expected due to the hypothesized major role of climatic factors in regulating species distributions. The stress‐gradient hypothesis suggests that biotic interactions may act as major constraints on species distributions under more favourable growing conditions, while climatic constraints may dominate under unfavourable conditions. We tested this hypothesis for one focal tree species having three major competitors using broad‐scale environmental data. We evaluated the variation of species co‐occurrence patterns in climate space and estimated the influence of these patterns on the distribution of the focal species for current and projected future climates. Location Europe. Methods We used ICP Forest Level 1 data as well as climatic, topographic and edaphic variables. First, correlations between the relative abundance of European beech (Fagus sylvatica) and three major competitor species (Picea abies, Pinus sylvestris and Quercus robur) were analysed in environmental space, and then projected to geographic space. Second, a sensitivity analysis was performed using generalized additive models (GAM) to evaluate where and how much the predicted F. sylvatica distribution varied under current and future climates if potential competitor species were included or excluded. We evaluated if these areas coincide with current species co‐occurrence patterns. Results Correlation analyses supported the stress‐gradient hypothesis: towards favourable growing conditions of F. sylvatica, its abundance was strongly linked to the abundance of its competitors, while this link weakened towards unfavourable growing conditions, with stronger correlations in the south and at low elevations than in the north and at high elevations. The sensitivity analysis showed a potential spatial segregation of species with changing climate and a pronounced shift of zones where co‐occurrence patterns may play a major role. Main conclusions Our results demonstrate the importance of species co‐occurrence patterns for calibrating improved species distribution models for use in projections of climate effects. The correlation approach is able to localize European areas where inclusion of biotic predictors is effective. The climate‐induced spatial segregation of the major tree species could have ecological and economic consequences.     

Genetic relationship of two mutant genes which producing three different syndromes in the mouse (author's transl)]

We determined that leaner gene (la) is located in the linkage group XVIII and closely linked to Es-1, which is known to be located closely to tottering gene (tg). Double heterozygote (la/tg) produced by mating between la heterozygote and tg heterozygote showed an intermediate syndrome between those seen in tottering (tg/tg) and leaner (la/la) mice. Both leaner and tottering mice showed neuromuscular disorders, but their clinical and pathological characteristics were different. Leaner mice were found to represent a so-called cerebellar mutant having the reduced size of cerebellum and severe cytoarchitectonic abnormalities with focal losses of Purkinje and granular layer cells. Tottering was, however, another mutation having epileptiform seizures, and it was characterized pathologically by cellular losses and shrinkage as well as vesiculations of cytoplasmic membranous structures in the cerebellum. The double heterozygote was shown to have both pathologic characteristics seen in each homozygote, and also showed shrinkage of Purkinje cells and vesiculation of the endoplasmic reticulum and Golgi apparatus. These clinical and pathological findings supported the genetic data suggesting that la and tg constitute an allele.     

Presence of haemocyte-like cells in coccinellid reflex blood

Abstract.  Contrary to current assumptions, the reflex blood of two-spot ladybirds, Adalia bipunctata , and seven-spot ladybirds, Coccinella septempunctata , contains haemocyte-like cells. Furthermore, DNA can be extracted and amplified from coccinellid reflex blood, confirming the presence of haemocyte-like cells and demonstrating a nondestructive method of DNA extraction.     

Autolysis in vitro of cotton (Gossypium hirsutum) fibre cell walls

Root growth of partly defoliated young peach seedlings [ Prunus persica (L.) Batsch. cv. Lovell] was significantly promoted by application of myo-inositol to the cut surface of the stem. Addition of benzylaminopurine (BA) combined with sucrose enhanced the promotive effect of myo-inositol on root growth, but addition of sucrose alone, suppressed it. Spraying rooted peach cuttings (nectarine cv. Sunred) with myo-inositol and defoliating them after 5 days increased the incorporation of amino acids into proteins in excised roots, obtained from the sprayed plants, as compared with roots from plants sprayed with water, or sucrose, or sucrose + myo-inositol. Myo-inositol applied in combination with kinetin or BA to stems of young peach seedlings (cv. Lovell) or rooted peach cuttings (cv. Almog) promoted the basipctal translocation of the two cytokinins in the stem and acropetally into the small lateral roots. Addition of sucrose voided this effect on the cytokinins. BA, when applied together with myo-inositol, was partly converted into an additional cytokinin-active compound in the roots.
Application of BA to either roots or tops of rooted peach cuttings (cv. Almog) resulted in the accumulation of myo-inositol (supplied through the cut surface of the stem) in the plant part to which BA had been applied.     

Glucose metabolism in isolated brown adipocytes under beta-adrenergic stimulation. Quantitative contribution of glucose to total thermogenesis.

To quantify the potential of brown adipose tissue as a target organ for glucose oxidation, O2 consumption and glucose metabolism in isolated rat brown adipocytes were measured in the presence and absence of insulin, by using the beta-agonists isoprenaline or Ro 16-8714 to stimulate thermogenesis. Basal metabolic rate (278 mumol of O2/h per g of lipid) was maximally stimulated with isoprenaline (20 nm) and Ro 16-8714 (20 microM) to 1633 and 1024 mumol of O2/h per g respectively, whereas insulin had no effect on O2 consumption. Total glucose uptake, derived from the sum of [U-14C]glucose incorporation into CO2 and total lipids and lactate release, was enhanced with insulin. Isoprenaline and Ro 16-8714 had no effect on insulin-induced glucose uptake, but promoted glucose oxidation while inhibiting insulin-dependent lipogenesis and lactate production. A maximal value for glucose oxidation was obtained under the combined action of Ro 16-8714 and insulin, which corresponded to an equivalent of 165 mumol of O2/h per g of lipid. This makes it clear that glucose is a minor substrate for isolated brown adipocytes, fuelling thermogenesis by a maximum of 16%.