Photosynthesis and water relations of almond tree cultivars grafted on two rootstocks

Five cultivars of Prunus amygdalus Batsch (Ferragnes, Ferrastar, Marcona, Garrigues, and Non Pareil) grafted on two different rootstocks (Garrigues and GF677), and two cultivars (Ferraduel and Casa Nova) grafted on GF677, were grown for three years under rainfed conditions in an orchard in northeast Portugal. Net photosynthetic rate (PN), leaf conductance for water vapour (gs), leaf water potential (Ψ), instantaneous water use efficiency (WUE), and internal CO2 concentration (Ci) were measured at three periods of the growing season: spring, summer (June or July) and late summer (September) over two years. Ferraduel, Ferrastar, and Marcona presented the best performance in the periods when environmental conditions were not very hard (May or September). Casa Nova and Non Pareil were well adapted to high air evaporative demand, preventing the increase of leaf temperature (T1). Ferrastar, although having a good performance in May and September, did well adapt to hard climatic conditions in June 1994. In the following year, although it presented the highest T1, the values were not limiting (30.6 ± 2.1 °C), and PN was only decreased from May to July. Marcona was highly dependent on T1, but prevented its increasing. Garrigues showed lower PN in most measurement periods. GF677 frequently induced the highest PN, WUE, and Ψ. PN was mainly dependent on T1, radiation, Ci, month, and year. WUE depended on the same factors. Ψ depended mainly on gs, air temperature, month, and year. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of low density lipoproteins and mevinolin on sympathetic responsiveness in cultured chick atrial cells. Regulation of beta-adrenergic receptors and alpha s

We have previously demonstrated that cultures of myocytes from embryonic chick atria grown in media supplemented with fetal calf serum from which lipoproteins have been removed demonstrate a nearly 10-fold increase in sensitivity of beating to the muscarinic cholinergic agonist carbamylcholine compared with cells grown with control medium. This increased response to carbamylcholine was associated with a 1.4-fold increase in total cell cholesterol, a 2-fold increase in the number of muscarinic receptors which bind agonist with high affinity, and a 2-fold increase in the levels of the alpha subunits of Go and Gi (Haigh, L. S., Leatherman, G. F., O'Hara, D. S., Smith, T. W., and Galper, J. B. (1988) J. Biol. Chem. 263, 15608-15618). In the studies reported here, we determined the responsiveness of cells grown in lipoprotein-depleted serum (LPDS) to beta-adrenergic stimulation. Isoproterenol stimulated a contractile response of 58% measured as an increase in amplitude of contraction with a half-maximal effect at 3 x 10(-7) M for cells grown in fetal calf serum, but had no significant effect on amplitude of contraction on cells grown in LPDS. In cells grown in media supplemented with fetal calf serum, isoproterenol (1 x 10(-3) M) stimulated adenylate cyclase activity 100% over basal with an EC50 of 7 x 10(-6) M compared with an increase of 32% in cells grown in media supplemented with LPDS. beta-Adrenergic receptor number as measured by the binding of 125I-pindolol decreased from 24 +/- 3 (+/- S.E., n = 6) fmol/mg protein in cells grown under control conditions to 12 +/- 2 (n = 6) fmol/mg protein in media supplemented with LPDS. The level of alpha s as measured both by ADP-ribosylation with cholera toxin in the presence of 32P-NAD and by immunoblotting with specific antibody to alpha s decreased by 3-fold in cells grown in media supplemented with LPDS compared with control. All of these effects of growth of cells in LPDS were reversed by incubating cells with LPDS plus 30 microM mevinolin, an inhibitor of endogenous cholesterol synthesis. These studies indicate that growth of cells in media supplemented with LPDS results in a coordinate decrease in the levels of beta-adrenergic receptors and alpha s. Taken together with our previous studies these data support the hypothesis that the receptors and guanine nucleotide-binding proteins which mediate sympathetic and parasympathetic responsiveness in the heart are reciprocally regulated.     

The Effects of Thallium on the Spontaneous Contraction of the Heart Muscle and the Energetic Processes in Cardiomyocyte Mitochondria

Biophysics - Abstract—Thallium ions were tested for their effect on the spontaneous contraction of the frog heart muscle and rat heart mitochondria. Tl+ ions reduced all parameters of...     

Role of Microbiota in Neurodegenerative Diseases

Russian Journal of Developmental Biology - Functional interaction of the gastrointestinal tract (GI) and the central nervous system (CNS) is due to various relationships, which includes autonomic...     

Surface Erosion of Metals under the Effect of Plasma Flows Typical of Transient Processes in Tokamaks

Plasma Physics Reports - It is shown theoretically that under the effect of plasma flows typical of transient processes in tokamaks not only can Kelvin–Helmholtz instability develop and waves...     

Age and growth of kaluga Acipenser dauricus from the estuary of the Amur and its lagoon

Age composition and the rate of growth of kaluga Acipenser dauricus from the estuary of the Amur and the Amur lagoon have been analyzed. Differences in the distribution of juvenile and mature individuals of kaluga in the river estuary and the lagoon were revealed. Males are dominant among mature individuals aged 18–26 years, and females are dominanat at an age 27–43 years. Females and males of the same age do not differ in length and body weight. A decrease in the rate of linear and gravimetric growth of mature individuals at the modern stage (2005–2008) compared to the period of 1965–1982 was revealed. Juvenile individuals of kaluga from the near-estuarine part of the Amur and its lagoon are inferior in the rate of growth to fish of the same age caught in the river channel, 500 km to the south.