Ozone‐induced stomatal sluggishness changes stomatal parameters of Jarvis‐type model in white birch and deciduous oak

• Stomatal ozone flux is closely related to ozone injury to plants. Jarvis‐type multiplicative model has been recommended for estimating stomatal ozone flux in forest trees. Ozone can change stomatal conductance by both stomatal closure and less efficient stomatal control (stomatal sluggishness). However, current Jarvis‐type models do not account for these ozone effects on stomatal conductance in forest trees.
• We examined seasonal course of stomatal conductance in two common deciduous tree species native to northern Japan (white birch: Betula platyphylla var. japonica ; deciduous oak: Quercus mongolica var. crispula ) grown under free‐air ozone exposure. We innovatively considered stomatal sluggishness in the Jarvis‐type model using a simple parameter, s , relating to cumulative ozone uptake (defined as POD : phytotoxic ozone dose).
• We found that ozone decreased stomatal conductance of white birch leaves after full expansion (?28%). However, such a reduction of stomatal conductance by ozone fell in late summer (?10%). At the same time, ozone reduced stomatal sensitivity of white birch to VPD and increased stomatal conductance under low light conditions. In contrast, in deciduous oak, ozone did not clearly change the model parameters.
• The consideration of both ozone‐induced stomatal closure and stomatal sluggishness improved the model performance to estimate stomatal conductance and to explain the dose–response relationship on ozone‐induced decline of photosynthesis of white birch. Our results indicate that ozone effects on stomatal conductance (i.e . stomatal closure and stomatal sluggishness) are crucial for modelling studies to determine stomatal response in deciduous trees, especially in species sensitive to ozone.

     

Characterization of the peptide-N4-(N-acetylglucosaminyl) asparagine amidase (PNGase Se) fromSilene alba cells

The peptide-N ⁴-(N-acetylglucosaminyl) asparagine amidase (PNGase Se) earlier described [Lhernould S., Karamanos Y., Bourgerie S., Strecker G., Julien R., Morvan H. (1992)Glycoconjugate J 9:191–97] was partially purified from culturedSilene alba cells using affinity chromatography. The enzyme is active between pH 3.0 and 6.5, and is stable in the presence of moderate concentrations of several other protein unfolding chemicals, but is readily inactivated by SDS. Although the enzyme cleaves the carbohydrate from a variety of animal and plant glycopeptides, it does not hydrolyse the carbohydrate from most of the corresponding unfolded glycoproteins in otherwise comparable conditions. The substrate specificity of this plant PNGase supports the hypothesis that this enzyme could be at the origin of the production of unconjugated N-glycans in a suspension medium of culturedSilene alba cells.Abbreviations GlcNAc N-acetylglucosamine - PNGase peptide-N ⁴-(N-acetylglucosaminyl) asparagine amidase - BSA bovine serum albumin - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis - TLC thin layer chromatography - HPAEC-PAD High pH anion exchange chromatography-pulsed amperometric detection     

Alterations in the activity of phospholipases A2 in postmortem white matter from patients with multiple sclerosis

Activities toward arachidonyl-labelled phospholipase A₂ substrates were assayed in fractions of white matter and cerebral cortex from control subjects and in fractions of demyelinated plaque, normal-appearing white matter and cerebral cortex from subjects who died with multiple sclerosis. Membranous activity at pH 8.6 in the presence of Ca²⁺, characteristic of 14 kDa secretory phospholipase A₂, in either multiple sclerosis white matter or cortex did not differ from controls, whereas membranous activity at pH 4.5 in the absence of added Ca²⁺, characteristic of lysosomal enzymes was increased over controls in both plaque and normal-appearing white matter but not cerebral cortex. Activity in the cytosol fraction, at pH 8.6 in the presence of Ca²⁺ and glycerol characteristic of the cytosolic 85 kDa enzyme was decreased by greater than 50% in both white matter and cortex samples from multiple sclerosis subjects. Immuno-precipitation and-blotting confirmed that the deficient activity was largely attributable to the 85 kDa enzyme although the enzyme protein was not similarly reduced.Special issue dedicated to Dr. Leon S. Wolfe.     

Mobilization of different phosphate fractions in the rhizosphere

Availability of soil P fractions and mechanisms of acquisition by plants were studied. Plants mobilize soil P by desorption via depletion of P solution concentration around roots. In an oxisol, the process was enhanced by nitrate N nutrition of ryegrass, which increased soil pH, and by carboxylate release by white lupin. Ligand exchange and Fe/Al solubilization are assumed to be the mechanisms. Ammonium N nutrition of ryegrass decreased pH and allowed P mobilization in a luvisol but had no such effect in an oxisol, due to acid solubility of P in these soils. Organic P dissolved in soil solution contributed one third to the P uptake of field-grown barley on a luvisol. Laboratory experiments suggest that organic P is hydrolyzed by phosphatases at the root surface and replenished by micro-organisms.     

感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察

用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。     

Reproductive biology of the white marlin (Kajikia albida) in the southwestern and equatorial Atlantic Ocean

The present work describes the reproductive biology of the white marlin (Kajikia albida) caught in the southwestern and equatorial Atlantic Ocean. The gonads of 924 fish were collected by observers on board Brazilian tuna longliners, between November 2004 and December 2006. The spawning season was assessed by the monthly frequency distribution of distinct stages of maturity and monthly mean female gonadosomatic index GSI. Sixty-one percent (n = 656) of the fish examined were female, with a Lower Jaw Fork Length (LJFL) between 83 and 236 cm (mean = 155.5 ± 16.63). The 268 males had a LJFL between 90 and 220 cm (mean = 152.3 ± 34.62). Although the northeastern region of Brazil does not appear to be a significant spawning area for the species, the results suggest a higher reproductive activity in the third quarter of the year. Using a Bayesian logistic model approach, length at 50% maturity was estimated at 145.04 cm (credibility interval of 95%, 143.94–146.09 cm), for females, and at 140.03 cm (credibility interval of 95%, 137.28–142.52 cm), for males.     

The dynamical response of hen egg white lysozyme to the binding of a carbohydrate ligand

It has become clear that the binding of small and large ligands to proteins can invoke significant changes in side chain and main chain motion in the fast picosecond to nanosecond timescale. Recently, the use of a "dynamical proxy" has indicated that changes in these motions often reflect significant changes in conformational entropy. These entropic contributions are sometimes of the same order as the total entropy of binding. Thus, it is important to understand the connections amongst motion between the manifold of states accessible to the native state of proteins, the corresponding entropy, and how this impacts the overall energetics of protein function. The interaction of proteins with carbohydrate ligands is central to a range of biological functions. Here, we examine a classic carbohydrate interaction with an enzyme: the binding of wild-type hen egg white lysozyme (HEWL) to the natural, competitive inhibitor chitotriose. Using NMR relaxation experiments, backbone amide and side chain methyl axial order parameters were obtained across apo and chitotriose-bound HEWL. Upon binding, changes in the apparent amplitude of picosecond to nanosecond main chain and side chain motions are seen across the protein. Indeed, binding of chitotriose renders a large contiguous fraction of HEWL effectively completely rigid. Changes in methyl flexibility are most pronounced closest to the binding site, but average to only a small overall change in the dynamics across the protein. The corresponding change in conformational entropy is unfavorable and estimated to be a significant fraction of the total binding entropy.     

Losartan Attenuates Insulin Resistance and Regulates Browning Phenomenon of White Adipose Tissue in ob/ob Mice

Insulin resistance (IR) is a villain role to the pathology of fatty liver diseases implicated in adipose tissue dysfunction, which is characterized by lipid droplets (LDs) accumulation and hypoxia-inducible factor 1α (HIF1α) related macrophage infiltration. HIF1α is required for its lipogenic actions in adipocytes, while and it regulates M1 and M2 polarization features of macrophages. Losartan has been shown to be an insulin sensitizer in obese states, actions involving in HIF1α signaling. However, the exact mechanisms accounting for these effects have not been fully elucidated. Therefore, GTT, ITT, and HOMA-IR were identified losartan alleviated IR signaling in obese mice. This alleviation may through inhibits HIF1α by suppressing STAT3-NF-κB signaling, which, in turn, revealed HIF1α-dependent decreases the angiogenesis pathway in adipose tissue, including regulation of VEGF and TGFβR2 levels. In white adipose tissue, a set of lipogenesis-related genes, Srebp1, Fas, and Scd-1 were markedly downregulated after losartan intervention, as well as reduced LDs size and LD-associated proteins, perilipin family proteins (PLINs) compared with obese mice. Losartan abolished macrophage infiltration with upregulation of M2 and inhibition of M1 macrophage markers in obese mice. Our data suggest that losartan attenuated obese-induced fatty liver, linked to alleviating inflammation in adipose tissues and a shift in M1/M2 macrophage balance. Furthermore, losartan might improve mitochondria biogenesis by upregulating SIRT1, PGC1α, UCP1, and mRNA of Tfam, Cd137, Tmem26, Ucp1 expression in white adipose tissue compared with the obese group. Taken together, losartan may improve IR and adipose dysfunction by inhibiting lipotoxicity and HIF1α pathways.