Reversal of Abscisic Acid-Induced Stomatal Closure by trans-Cinnamic and p-Coumaric Acid

Abscisic acid (ABA)-induced increase in stomatal diffusive resistance (SDR) in excised leaves of bean (Phaseolus vulgaris L. cv Pencil Pod) and maize (Zea mays L. cv Golden Bantam) is inhibited by low concentrations of trans-cinnamic acid (TCA) (1 micromolar) and p-coumaric acid (PCA) (10 micromolar) when given together with ABA (10 micromolar) in the transpiration stream through the cut end of the petiole or leaf blade. A concentration effect is observed both in the ABA action and its reversal by phenolic acids. Leaves having attained a high diffusive resistance in ABA solution recover rapidly when transferred to water. ABA (10 micromolar) induced closure of the stomata in onion, Allium cepa L. and Vicia faba epidermal peels. This is associated with loss of K⁺ from guard cells. In the presence of TCA (10 micromolar) and PCA (10 micromolar) K⁺ is retained in the guard cells with open stomata. The dark closure of stomata is also inhibited by TCA and PCA. It is suggested that these phenolic acids may inhibit the ABA effect by competing with or acting on some ABA-specific site, probably located on the plasma membrane, regulating flux of K⁺ ions. A weak association of ABA with the plasma membrane is envisaged because of the rapid recovery obtained upon transferral of the leaves to water.     

Lack of effect of somatostatin on the stimulation of hepatic glycogenolysis by epinephrine in isolated canine hepatocytes

The effects of somatostatin on epinephrine's ability to stimulate glucose output have been examined in hepatocytes isolated from dogs fasted overnight. Half-maximal stimulation of phosphorylase a activity and glucose output occurred at an epinephrine concentration of approx. 5 X 10(-9) M. Somatostatin at 10, 100 or 1000 ng/ml had no effect on the ability of a maximal (1 X 10(-7) M) and a submaximal (1 X 10(-8) M) dose of epinephrine to activate phosphorylase at 2 min, or to stimulate glucose output over 20 min. Since the doses of somatostatin used in the present study are up to 50-fold higher than the blood concentrations commonly found when somatostatin is used in vivo to inhibit pancreatic hormone secretion, it seems unlikely that use of somatostatin in this way would affect stimulation of hepatic glycogenolysis by epinephrine in vivo.     

小麦族植物的分类现状及主要存在的问题

小麦族(Triticeae)是禾本科、早熟禾亚科中一个有重要经济价值、以多年生植物占优势的族,族内绝大多数种类是重要的粮食作物和畜牧业上的优良牧草,饲用价值极高,有些种类具有耐寒、耐旱、耐碱等特性,是农牧业上良种繁育、牧草利用的重要基因资源。但该族同时又是分类学上的一个疑难族,各学者对族内系统分类意见不一、争议颇大,尤其在族的界限、族下类群划分以及类群演化关系上问题较多,至今尚未解决。查阅了国内外分类学文献,探讨其分类差异以及存在问题,为充分开发利用中国丰富的小麦族植物资源提供理论依据。     

Proteomic mapping for legume nodule organogenesis

While genetic screens have identified mutants of the model legume Lotus japonicus that can nodulate in the absence of rhizobia, the lack of a proteome map is a major hindrance to understanding the functional protein networks associated with this nodulation process. In this issue of Proteomics, Dam et al. (Proteomics 2014, 14, 230–240) developed 2D gel‐based reference maps of nodules and roots of Lotus and a spontaneous nodule formation mutant (snf1). Comparative proteomic analysis of roots and two developmental stages of nodules provide useful insights into tissue‐specific mechanisms underlying nodule organogenesis. Additionally, a comparison of interspecies nodule proteomes displays that overlapping and individual mechanisms are associated with legume nodulation.     

Somatic embryogenesis in Eucalyptus globulus

Somatic embryos were obtained from 1% of cotyledon pieces and hypocotyls of mature embryos of Eucalyptus globulus Labill. cultured on media containing a high concentration of picloram or IBA. 2,4-D and other synthetic auxins did not yield somatic embryos or embryogenic callus. Somatic embryos arose indirectly via callus, being visible after four months, and directly, where little callus or adventitious root initiation occurred. Somatic embryos, formed directly from explants, were visible within five weeks. Various structural abnormalities of somatic embryos were observed, especially after induction on media containing picloram. Only two out of fifteen somatic embryos showed hypocotyl and radical elongation, but plantlets did not develop further.     

Lipoteichoic acid is an important microbe-associated molecular pattern of Lactobacillus rhamnosus GG

Background

Receptors with a single transmembrane (TM) domain are essential for the signal transduction across the cell membrane. NMR spectroscopy is a powerful tool to study structure of the single TM domain. The expression and purification of a TM domain in Escherichia coli (E.coli) is challenging due to its small molecular weight. Although ketosteroid isomerase (KSI) is a commonly used affinity tag for expression and purification of short peptides, KSI tag needs to be removed with the toxic reagent cyanogen bromide (CNBr).

Result

The purification of the TM domain of p75 neurotrophin receptor using a KSI tag with the introduction of a thrombin cleavage site is described herein. The recombinant fusion protein was refolded into micelles and was cleaved with thrombin. Studies showed that purified protein could be used for structural study using NMR spectroscopy.

Conclusions

These results provide another strategy for obtaining a single TM domain for structural studies without using toxic chemical digestion or acid to remove the fusion tag. The purified TM domain of p75 neurotrophin receptor will be useful for structural studies.     

Analysis of gene expression in a human cell line stably transduced with herpesvirus saimiri

Herpesvirus saimiri (HVS) is the prototype gamma-2 herpesvirus; it has significant homology to the human gammaherpesviruses Kaposi's sarcoma-associated virus and Epstein-Barr virus and the murine gammaherpesvirus murine herpesvirus 68. HVS causes a persistent asymptomatic infection in its natural host, the squirrel monkey. Both subgroups A and C possess the ability to immortalize common marmoset T lymphocytes to interleukin-2-independent proliferation. However, only subgroup C is capable of transforming human, rabbit, and rhesus monkey lymphocytes in vitro. In addition, HVS can stably transduce a variety of human cell lines where the virus persists as a nonintegrating circular episome. In this study, we have developed a system in which the HVS DNA is stably maintained as a nonintegrated circular episome in the human lung carcinoma cell line A549. Virus production can be reactivated using chemical inducing agents, including tetradecanoyl phorbol acetate and n-butyrate, suggesting that the infection in human A549 cells is latent. To analyze virus gene expression in these stably transduced cells, Northern blot analysis was performed using a series of probes produced from restriction fragments spanning the entire coding region of the HVS genome. This demonstrated that an adjacent set of genes containing open reading frames (ORFs) 71 to 73 are expressed in this stably transduced cell line. Moreover, these genes are transcribed as a polycistronic mRNA species produced from a common promoter upstream of ORF 73. This model may serve as a useful tool in the further analysis of the role of ORFs 71 to 73 in gamma-2 herpesvirus latency.     

Translocation of phospholipid/Ca2+-dependent protein kinase in B-lymphocytes activated by phorbol ester or cross-linking of membrane immunoglobulin.

Treatment of hepatocytes with islet activating protein (pertussis toxin) from Bordetella pertussis blocked the ability of insulin to inhibit adenylate cyclase activity both in broken plasma membranes and in intact hepatocytes. Such treatment of intact hepatocytes with pertussis toxin did not prevent insulin from activating the peripheral plasma membrane cyclic AMP phosphodiesterase although it did inhibit the ability of insulin to activate the 'dense-vesicle' cyclic AMP phosphodiesterase. The ability of glucagon pretreatment of hepatocytes to block insulin's activation of the plasma membrane cyclic AMP phosphodiesterase was abolished in pertussis toxin-treated hepatocytes. It is suggested that the ability of insulin to manipulate cyclic AMP concentrations by inhibiting adenylate cyclase and activating the plasma membrane and 'dense-vesicle' cyclic AMP phosphodiesterases involves interactions with the guanine nucleotide regulatory protein system occurring in liver plasma membranes.     

Plasma carbonyls do not correlate with lung function or computed tomography measures of lung density in older smokers.

Oxidative stress and inflammation are hallmarks of chronic obstructive pulmonary disease (COPD). A critical byproduct of oxidative damage is the introduction of carbonyl groups into amino acid residues. We hypothesize that plasma carbonyl content is inversely correlated with lung function and computed tomography (CT) measures of lung density among smokers and is elevated in COPD. Carbonyl was measured in plasma of participants aged 60 years and older by ELISA. Generalized linear and additive models were used to adjust for potential confounders. Among 541 participants (52% male, mean age 67 years, 41% current smokers), mean plasma carbonyl content was 17.9+/-2.9 nmol ml(-1) and mean forced expiratory volume in one second (FEV(1)) was 80.7+/-20.9% of predicted. Plasma carbonyl content was inversely associated with FEV(1), but this relationship was largely explained by age. Multivariate analyses ruled out clinically meaningful associations of plasma carbonyl content with FEV(1), FEV(1)/FVC (forced vital capacity) ratio, severity of airflow obstruction, and CT lung density. Plasma carbonyl content is a poor biomarker of oxidative stress in COPD and emphysema.