Direct electrochemistry and electrocatalysis of heme-proteins entrapped in agarose hydrogel films

Three heme-proteins, including myoglobin (Mb), hemoglobin (Hb) and horseradish peroxidase (HRP), were immobilized on edge-plane pyrolytic graphite (EPG) electrodes by agarose hydrogel. The proteins entrapped in the agarose film undergo fast direct electron transfer reactions, corresponding to FeIII = e- --> FeII. The formal potential (E degrees'), the apparent coverage (Gamma), the electron transfer coefficient (alpha) and the apparent electron transfer rate constant (ks) were calculated by integrating cyclic voltammograms or performing nonlinear regression analysis of square wave voltammetric (SWV) experimental data. The E degrees's are linearly dependent on solution pH (redox Bohr effect), indicating that the electron transfer was proton-coupled. Ultraviolet visible (UV-Vis) and reflection-absorption infrared (RAIR) spectra suggest that the conformation of proteins in the agarose film are little different from that proteins alone, and the conformation changes reversibly in the range of pH 3.0-10.0. Atomic force microscopy (AFM) images of the agarose film indicate a stable and crystal-like structure formed possibly due to the synergistic interaction of hydrogen bonding between N,N-dimethylformamide (DMF), agarose hydrogel and heme-proteins. This suggests a strong interaction between the heme-proteins and the agarose hydrogel. DMF plays an important role in immobilizing proteins and enhancing electron transfer between proteins and electrodes. The mechanisms for catalytic reduction of hydrogen peroxide and nitric oxide (NO) by proteins entrapped in agarose hydrogel were also explored.     

Collagen-binding motif peptide, a cleavage product of osteopontin, stimulates human neutrophil chemotaxis via pertussis toxin-sensitive G protein-mediated signaling

The collagen-binding motif (CBM) peptide, a cleavage product of osteopontin (OPN), stimulated intracellular calcium increase in human neutrophils. CBM peptide-stimulated calcium was inhibited by pertussis toxin (PTX), suggesting the influence of PTX-sensitive G-proteins. In addition CBM peptide stimulated the chemotactic migration of human neutrophils and human monocytes. CBM peptide-induced neutrophil chemotaxis was completely inhibited by PTX, once again indicating the influence of Gi proteins. CBM peptide was also found to induce mitogen activated protein kinase activation. CBM peptide-induced neutrophil chemotaxis was mediated by p38 kinase as well as an extracellular signal-regulated protein kinase. Taken together, the results suggest that a cleavage product of OPN, CBM peptide, initiates immune responses by inducing neutrophil trafficking via certain PTX-sensitive cell surface receptors.     

Ohmefentanyl stereoisomers induce changes of CREB phosphorylation in hippocampus of mice in conditioned place preference paradigm

The present study was designed to determine the changes of phosphorylation of cAMP-response element binding protein(CREB)in hippocampus induced by ohmefentanyl stereoisomers(F9202 and F9204) in conditioned place preference(CPP)paradigm.The results showed that mice receiving F9202 and F9204 displayed obvious CPP.They could all significantly stimulate CREB phosphorylation and maintained for a long time without affecting total CREB protein levels.The effect of F9204 was similar to morphine which effect was more potent and longer than F9202.We also examined the effects of ketamine,a noncompetitive N-mthyl-D-asartate receptor(NR)antagonist,on morphine-,F9202-and F9204-induced CPP and phosphorylation of CREB in hippocampus.Ketamine could suppress not only the place preference but also the phosphorylation of CREB produced by morphine,F9202 and F9204.These findings suggest that alterations in the phosphorylation of CREB be relevant to opiates signaling and the development of opiates dependence.NR antagonists may interfere with opiates dependence and may have potential therapeutic implications.     

House dust mite extract activates apical Cl− channels through protease‐activated receptor 2 in human airway epithelia

Adequate fluid secretion from airway mucosa is essential for maintaining mucociliary clearance, and fluid hypersecretion is a prominent feature of inflammatory airway diseases such as allergic rhinitis. House dust mite extract (HDM) has been reported to activate protease‐activated receptors (PARs), which play various roles in airway epithelia. However, the role of HDM in regulating ion transporters and fluid secretion has not been investigated. We examined the effect of HDM on ion transport in human primary nasal epithelial cells. The Ca²⁺‐sensitive dye Fura2‐AM was used to determine intracellular Ca²⁺ concentration ([Ca²⁺]_i) by means of spectrofluorometry in human normal nasal epithelial cells (NHNE). Short‐circuit current (Isc) was measured using Ussing chambers. Fluid secretion from porcine airway mucosa was observed by optical measurement. HDM extract (10 µg/Ml) effectively cleaved the PAR‐2 peptide and induced an increase of [Ca²⁺]_i that was abolished by desensitization with trypsin, but not with thrombin. Apical application of HDM‐induced Isc sensitive to both a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor and a Ca²⁺‐activated Cl^? channel (CaCC) inhibitor. HDM extract also stimulated fluid secretion from porcine airway mucosa. HDM extract activated PAR‐2 and apical Cl^? secretion via CaCC and CFTR, and HDM‐induced fluid secretion in porcine airway mucosa. Our results suggest a role for PAR‐2 in mucociliary clearance and fluid hypersecretion of airway mucosa in response to air‐borne allergens such as HDM. J. Cell. Biochem. 109: 1254–1263, 2010. © 2010 Wiley‐Liss, Inc.     

Mapping-by-Sequencing Identifies HvPHYTOCHROME C as a Candidate Gene for the early maturity 5 Locus Modulating the Circadian Clock and Photoperiodic Flowering in Barley

Phytochromes play an important role in light signaling and photoperiodic control of flowering time in plants. Here we propose that the red/far-red light photoreceptor HvPHYTOCHROME C (HvPHYC), carrying a mutation in a conserved region of the GAF domain, is a candidate underlying the early maturity 5 locus in barley (Hordeum vulgare L.). We fine mapped the gene using a mapping-by-sequencing approach applied on the whole-exome capture data from bulked early flowering segregants derived from a backcross of the Bowman(eam5) introgression line. We demonstrate that eam5 disrupts circadian expression of clock genes. Moreover, it interacts with the major photoperiod response gene Ppd-H1 to accelerate flowering under noninductive short days. Our results suggest that HvPHYC participates in transmission of light signals to the circadian clock and thus modulates light-dependent processes such as photoperiodic regulation of flowering.     

Functional and crystal structure analysis of active site adaptations of a potent anti-angiogenic human tRNA synthetase

Higher eukaryote tRNA synthetases have expanded functions that come from enlarged, more differentiated structures that were adapted to fit aminoacylation function. How those adaptations affect catalytic mechanisms is not known. Presented here is the structure of a catalytically active natural splice variant of human tryptophanyl-tRNA synthetase (TrpRS) that is a potent angiostatic factor. This and related structures suggest that a eukaryote-specific N-terminal extension of the core enzyme changed substrate recognition by forming an active site cap. At the junction of the extension and core catalytic unit, an arginine is recruited to replace a missing landmark lysine almost 200 residues away. Mutagenesis, rapid kinetic, and substrate binding studies support the functional significance of the cap and arginine recruitment. Thus, the enzyme function of human TrpRS has switched more to the N terminus of the sequence. This switch has the effect of creating selective pressure to retain the N-terminal extension for functional expansion.     

Screening and degradation performances of dominant strains in high-salinity landfill leachate

In order to enhance the removal efficiency of chemical oxygen demand (COD) in the high-salinity landfill leachate, the dominant strains were isolated from high-salinity landfill leachate. The dominant strains and bacteria consortium were screened for COD treatment potential using an aerobic COD concentration decrease test. Ten strains, TJ01–TJ10, were isolated, of which six strains TJ02, TJ03, TJ05, TJ06, TJ07, and TJ09 were found to have higher COD removal when the single bacteria were added, all more than 20%. The most effective combination was TJ06 + TJ09; the COD removal efficiency reached 45.57%. 16S rDNA gene sequence analysis revealed that TJ06 and TJ09 belonged to the genus Bacillus. The effects of the dominant bacteria consortium on the high-salinity landfill leachate varied with pH value and the volume fraction of leachate. The COD removal efficiencies maintained higher when the pH value was 6–8 and the volume fractions of leachate were less than 80%. The result also suggested that there is little effect on the growth of TJ06 and TJ09 when the range of Cl⁻ concentration is 0–30,000 mg/L.     

最大信息熵原理与群体遗传平衡

建立了用最大信息熵原理推导群体遗传平衡定律的统一数学模型,并给出了模型的统一解,此解正是Hardy-Weinberg定律所给出的平衡群体的基因型频率,说明当群体信息熵达到最大时,群体基因型频率不再变化,即达到“平衡”。这证明了最大熵分布就是Hardy-Weinberg平衡分布。Hardy-Weinberg平衡定律与最大信息熵原理的内在一致性说明,杂交和随机交配是一个不可逆过程,使群体基因型信息熵增大,无序性增,是选择和近亲交配使群体的信息熵降低,有序性增加,育种过程实际就是调节群体信息熵的过程。过程信息熵的含义是表示一个概率分布的不确定性,最大熵原理意味着在一定的约束条件,选择具有最大不确定性的分布,从而其分布是最为随机的。最大熵原理在信息,工程,天文,地理,图像处理,模式识别等自然科学和社会科学领域都有广泛的成功应用,本文从群体遗传学角度证明了这一原理具有普遍适用性。熵是描述系统状态的函数,而最大熵原理则表明了系统发展变化的趋势,系统的最终状态必然是熵增加至最大值的状态,对于任何系统都是如此。因此,群体遗传系统的平衡定律可以统一用最大熵原理进行判定和描述;任意群体的基因型信息熵在随机交配世代传递时有不断增加的趋势;在一定约束条件下基因型信息熵达到最大值时,就称之为达到遗传平衡。本文将信息论原理应用于群体遗传学研究,揭示了基因信息熵的生物学意义,并表明可以用信息学和控制论的原理和方法来研究群体遗传学问题。     

菱纹叶蝉属中国种类记要(同翅目,叶蝉科,殃叶蝉亚科)

记述中国菱纹叶蝉属Hishimonus Ishihara 17种,其中有2新种,即长突菱纹叶蝉H.prolongatus sp.nov.和褐斑菱纹叶蝉H.fuscomaculatus sp.nov..新种模式标本保存在贵州大学昆虫研究所.