早期帕金森病大鼠血清抗氧化能力降低

目的：研究早期帕金森病（PD）大鼠血清抗氧化能力的改变。方法：观察6-羟多巴胺（6-OHDA）早期PD大鼠多巴胺（DA）能神经元和血清抗氧化能力的异常改变。结果：早期PD动物DA能神经元的数量明显减少,血清抗氧化能力明显降低。结论：早期PD大鼠血清抗氧化能力降低,这可能与DA能神经元损伤有关。     

TRPC1 protects dopaminergic SH-SY5Y cells from MPP＋, salsolinol,and N-methyl-（R）-salsolinol-induced cytotoxicity

Neurotoxins and alterations in Ca2＋ homeostasis have been associated with Parkinson＇s disease （PD）, but the role of store-operated Ca2＋ entry channels is not well understood. Previous studies have shown the neurotoxicity of salsolinol and 1-methyl-4-phenylpyridinium ion on SH-SY5Y cells and cytoprotection induced by transient receptor potential protein 1 （TRPC1）. In the present study, N-methyl-（R）-salsolinol was tested for its cellular toxicity and effects on TRPC1 expression. MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-dipbenyl- tetrazolium bromide） assays, DAPI （4＇,6-diamidino-2-pheny- lindole）, fluorescein isothiocyanate-Annexin-V/propidium iodide, western blot analysis, and JC-1 labeling revealed that the three indicated drugs could induce caspase-dependent, mitochondrial-mediated apoptosis. Exposure of SH-SY5Y cells to the indicated drugs resulted in a significant decrease in thapsigargin-mediated Ca2＋ influx and TRPC1 expression. Immnnocytochemistry experiments revealed that neurotoxins treatment induced TRPC1 translocation to the cytoplasm. Taken together, our results indicate that treatment with neurotoxins may alter Ca2＋ homeostasis and induce mitochondrial-mediated caspase-dependent cytotoxicity, an important characteristic of PD.     

Gene expression profiles of sodium-dependent vitamin C transporters in mice after alcohol consumption

Alcoholic liver disease （ALD） is a serious fiver problem in western countries. Our previous study has demonstrated that vitamin C plays a protective role in ALD. The vitamin C homeostasis is tightly regulated by sodium-dependent vitamin C transporters （SVCTs） 1 and 2. But the role of two SVCTs in ALD is less understood. In this study, we exam- ined the expression patterns of two SVCTs in mice after alcohol consumption. Our results suggested that alcohol con- sumption obviously increased the expression of two SVCTs in liver and SVCT1 in kidney and intestine, which is important for vitamin C absorption. Vitamin C supplement increased the sera vitamin C content and ameliorated the symptom of ALD. Intestinal absorption and renal re-absorption mediated by SVCTI are key factors to increase the sera vitamin C content after alcohol consumption. We proposed that both reactive oxygen species and low vitamin C concentration regulate the expression of SVCTs, and the protective role of vitamin C is mediated by suppressing the stability of hypoxia-inducible factor-loL. Thus, our study is significant for the understanding of vitamin C homeostasis in ALD and for better use of other antioxidants in ALD therapy.     

清热解毒中药干预大鼠急性心肌缺血损伤的实验研究

目的：研究清热解毒中药干预大鼠急性心肌缺血损伤的药效学,探讨其治疗冠心痛心肌缺血的作用机制。方法：复制大鼠急性心肌缺血模型,以肌酸激酶（CK）、乳酸盐脱氢酶（LDH）、肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）、一氧化氮（NO）、一氧化氮合成酶（NOS）、超氧化物歧化酶（SOD）、丙二醛（MDA）为观测指标,以地尔硫卓为平行对照,观察清热解毒中药干预冠心病心肌缺血的作用机制。结果：清热解毒中药能显著降低模型大鼠血清中CK、LDH活性、MDA含量、TNF-α与IL-6水平及显著升高模型大鼠血清中SOD活力、NO与NOS水平（P〈0．05,P〈0．01）。结论：清热解毒中药能够保护缺血心肌。     

Decipher the mechanisms of rabbit＇s low susceptibility to prion infection

Rabbits have low susceptibility to prion infection. Studies on prion protein （PrP） from animal species of different sus- ceptibility to prion diseases identified key amino acid resi- dues, specific motif, and special features in rabbit prion protein （RaPrPc） that contribute to the stability of rabbit PrP~ and low susceptibility to prion infection. However, there is no evidence showing that rabbits are completely re- sistant to prion diseases. It has been reported that the rabbit prion could be generated in vitro through protein misfolding cyclic amplification and proved to be infectious and transmissible. Here, we reviewed studies on rabbit- specific PrP structures and features in relation to rabbit＇s low susceptibility to prion infection.     

Redox Regulation of Arabidopsis Mitochondrial Citrate Synthase

Citrate synthase has a key role in the tricarboxylic （TCA） cycle of mitochondria of all organisms, as it cata- lyzes the first committed step which is the fusion of a carbon-carbon bond between oxaloacetate and acetyl CoA. The regulation of TCA cycle function is especially important in plants, since mitochondrial activities have to be coordinated with photosynthesis. The posttranslational regulation of TCA cycle activity in plants is thus far almost entirely unexplored. Although several TCA cycle enzymes have been identified as thioredoxin targets in vitro, the existence of any thioredoxin-dependent regulation as known for the Calvin cycle, yet remains to be demonstrated. Here we have investigated the redox regulation of the Arabidopsis citrate synthase enzyme by site-directed mutagenesis of its six cysteine residues. Our results indicate that oxidation inhibits the enzyme activity by the formation of mixed disulfides, as the partially oxidized citrate synthase enzyme forms large redox-dependent aggregates. Furthermore, we were able to demonstrate that thioredoxin can cleave diverse intraas well as intermolecular disulfide bridges, which strongly enhances the activity of the enzyme. Activity measurements with the cysteine variants of the enzyme revealed important cysteine residues affecting total enzyme activity as well as the redox sensitivity of the enzyme.     

Cell Wall,Cytoskeleton, and Cell Expansion in Higher Plants

To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.     

A New Set of Reversibly Photoswitchable Fluorescent Proteins for Use in Transgenic Plants

Fluorescent reporter proteins that allow repeated switching between a fluorescent and a non-fluorescent state in response to specific wavelengths of light are novel tools for monitoring of protein trafficking and super-resolu- tion fluorescence microscopy in living organisms. Here, we describe variants of the reversibly photoswitchable fluores- cent proteins rsFastLime, bsDronpa, and Padron that have been codon-optimized for the use in transgenic Arabidopsis plants. The synthetic proteins, designated rsFastLIME-s, bsDRONPA-s, and PADRON C-s, showed photophysical properties and switching behavior comparable to those reported for the original proteins. By combining the ＇positively switchable＇ PADRON C-s with the ＇negatively switchable＇ rsFastLIME-s or bsDRONPA-s, two different fluorescent reporter proteins could be imaged at the same wavelength upon transient expression in Nicotiana benthamiana cells. Thus, co-localiza- tion analysis can be performed using only a single detection channel. Furthermore, the proteins were used to tag the RNA-binding protein AtGRP7 （Arabidopsis thaliana glycine-rich RNA-binding protein 7） in transgenic Arabidopsis plants. Because the new reversibly photoswitchable fluorescent proteins show an increase in signal strength during each pho- toactivation cycle, we were able to generate a large number of scans of the same region and reconstruct 3-D images of AtGRP7 expression in the root tip. Upon photoactivation of the AtGRP7：rsFastLIME-s fusion protein in a defined region of a transgenic Arabidopsis root, spreading of the fluorescence signal into adjacent regions was observed, indicating that movement from cell to cell can be monitored. Our results demonstrate that rsFastLIME-s, bsDRONPA-s, and PADRON C-s are versatile fluorescent markers in plants, Furthermore, the proteins also show strong fluorescence in mammalian cells including COS-7 and HeLa cells.     

Dissecting the Heat Stress Response in Chlamydomonas by Pharmaceutical and RNAi Approaches Reveals Conserved and Novel Aspects

To study how conserved fundamental concepts of the heat stress response （HSR） are in photosynthetic eukaryotes, we applied pharmaceutical and antisense/amiRNA approaches to the unicellular green alga Chlamydomonas reinhardtii. The Chlamydomonas HSR appears to be triggered by the accumulation of unfolded proteins, as it was induced at ambient temperatures by feeding cells with the arginine analog canavanine. The protein kinase inhibitor staurosporine strongly retarded the HSR, demonstrating the importance of phosphorylation during activation of the HSR also in Chlamydomonas. While the removal of extracellular calcium by the application of EGTA and BAPTA inhibited the HSR in moss and higher plants, only the addition of BAPTA, but not of EGTA, retarded the HSR and impaired thermotoler- ance in Chlamydomonas. The addition of cycloheximide, an inhibitor of cytosolic protein synthesis, abolished the attenu- ation of the HSR, indicating that protein synthesis is necessary to restore proteostasis. HSP90 inhibitors induced a stress response when added at ambient conditions and retarded attenuation of the HSR at elevated temperatures. In addition, we detected a direct physical interaction between cytosolic HSP90A/HSP70A and heat shock factor 1, but surprisingly this interaction persisted after the onset of stress. Finally, the expression of antisense constructs targeting chloroplast HSP70B resulted in a delay of the cell＇s entire HSR, thus suggesting the existence of a retrograde stress signaling cascade that is desensitized in HSP7OB-antisense strains.     

Effect of Smac and Taxol on non-small-cell lung cancer

A series of structurally unique second mitochondria-derived activator of caspases （Smacs） that act as antagonists of the inhibitor of apoptosis proteins （IAPs） directly have been discovered. They play crucial roles in mitochondrial apoptosis pathways and promote chemotherapy-induced apoptosis. In this study, we constructed a eukaryotic expression vector pcDNA3.1/Smac and transfected it into A549 human lung cancer cells. Then we analyzed the cell invasive and cloning ability, as well as cell apoptosis induced by Taxol. The results showed that over-expressed Smac significantly inhibited A549 cell invasive and cloning ability and promoted apoptosis following Taxol treatment. This finding provides a potential approach for the biological therapy of lung cancer.     

Avian genetic ecotoxicology： DNA of the canary in a coalmine

Genotoxic chemicals, through damage and alteration of the genetic material of wild organisms, pose significant threats to the persistence of wild animal populations. Their damaging effects can ultimately impair the health of the ecosystem and its provision of services to human society. Bird species are good candidates for the role of sentinels of the effects of genotoxins, thanks to （i） the diversity of their ecological niches, （ii） their ubiquity across environments, （iii） their conspicuousness, abundance and approachability, together with （iv） their well-known life histories and the availability of historical data series. Avian diversity increases the likelihood that adequate model species be available for monitoring genotoxicants and assessing their impact. This paper reviews the methods utilized by genetic ecotoxicological studies of wild birds, highlighting their benefits and shortcomings. It also summarizes the genetic ecotoxicological studies so far conducted. In spite of a paucity of studies, several classes of genotoxicants have already been investigated across a variety of species and environments, thus supporting the versatility of birds as monitors of genotoxic contamination. Future technical advancements and applications are suggested, with par- ticular reference to the analysis of mutational events, gene expression and methylation patterns. Finally, I argue that the development of avian genetic ecotoxicology will contribute to the understanding of natural variation in the underlying machinery for coping with DNA damage and oxidative stress, both of which are increasingly recognized as proximate factors in the evolution of life history adaptations [Current Zoology 60 （2）： 285-298, 2014].     

How does the host-specialized aphid deal with food deficiency？

Aphis gossypii Glover shows obvious host specialization, with cucurbit- and cotton-specialized biotypes or host races in many regions. Because its annual natal hostcrops senesce earlier the cucurbit-specialized biotype may suffer food deficiency. The method this biotype uses to overcome this challenge is still poorly understood. In orderto understand the potential of the cucurbit-specialized biotype aphids in host shift and usage, the performance of this biotype on cotton （Gossypium hirsutum）, a common butpoor quality host plant, was explored in this study. The cucurbit-specialized aphids could establish populations on cotton only when these plants had at least nine leaves, and subsequent populations developed rather slowly. The presence of whitefly populations on cotton improved the success rate of cucurbit-specialized aphids. The cucurbit-specialized aphidswere mainly distributed on the older leaves of cotton, with only a few settling on the upper leaves. The cucurbit-specialized aphids reared on cotton for 40, 54 and 61 days stillmaintained strong preference for their natal host plant, cucumber （Cucumis sativus）, rather than cotton, and their net reproductive rates and intrinsic rates of natural increase weredramatically lower when they were transferred onto new six-leaf cotton plants or detached leaves. Therefore, we concluded that the cucurbit-specialized aphids have the potentialto utilize mature or whitefly-stressed cotton plants, but that this feeding experience on cotton did not alter their specialization for cucurbits. Some cotton plants could act as atemporary host for the cucurbit-specialized aphids to overcome food deficiency arising from senescing cucurbits.     

Genotoxicity biomarkers in aquatic bioindicators

Pollution of the aquatic environment is an ever-growing problem, as waters are the ultimate sink for the large number of xenobiotics from multiple sources. DNA damaging agents have a significant ecological relevance since they are implicated in many pathological processes and exert effects beyond that of individual being active through following generations. A large number of methods have been applied to evaluate genotoxic damage in different aquatic species. Comet assay, as method for de- tecting DNA alterations, and micronucleus test, as an index of chromosomal damage are the most widely applied and validated methods in field studies. These methods were applied in different vertebrate and invertebrate aquatic species, but only mollusk and fish species have been employed in routine biomonitoring programs. Mussels, due to their widely geographical distribution and the suitability for caging represent the bioindicator of choice in field studies. Mytilus species is the most used marine mussel. The use of fish is limited to specific geographic areas. The present review mainly focuses on the application of comet assay and micronucleus test in mussels. A number of biomonitoring studies in mussels, using comet assay or micronucleus test, revealed exposure to different classes of genotoxic compounds with a good discrimination power. The different evidence from the two as- says, reflects different biological mechanisms for the two genetic endpoints, DNA damage and chromosomal damage, suggesting their combined application in the field. Different endogenous and exogenous factors have been shown to modulate the genotoxic responses in mussels, acting as confounding factors in environmental monitoring. The use of standardized protocol for caging, sampling and genotoxity evaluation is critical in biomonitoring studies. The use of a multimarker approach coupling genotoxicity biomarkers with physiological and biochemical factors allows to have a complete picture of the environmental pollution [Current Zoology 60 （2）： 273-284, 2014].     

Knights in Action： Lectin Receptor-Like Kinases in Plant Development and Stress Responses

The Receptor-Like Kinase （RLK） is a vast protein family with over 600 genes in Arabidopsis and 1100 in rice. The Lectin RLK （LecRLK） family is believed to play crucial roles in saccharide signaling as well as stress perception. All the LecRLKs possess three domains： an N-terminal lectin domain, an intermediate transmembrane domain, and a C-terminal kinase domain. On the basis of lectin domain variability, LecRLKs have been subgrouped into three subclasses： L-, G-, and C-type LecRLKs. While the previous studies on LecRLKs were dedicated to classification, comparative structural analysis and expression analysis by promoter-based studies, most of the recent studies on LecRLKs have laid special emphasis on the potential of this gene family in regulating biotic/abiotic stress and developmental pathways in plants, thus mak- ing the prospects of studying the LecRLK-mediated regulatory mechanism exceptionally promising. In this review, we have described in detail the LecRLK gene family with respect to a historical, evolutionary, and structural point of view. Furthermore, we have laid emphasis on the LecRLKs roles in development, stress conditions, and hormonal response. We have also discussed the exciting research prospects offered by the current knowledge on the LecRLK gene family. The multitude of the LecRLK gene family members and their functional diversity mark these genes as both interesting and worthy candidates for further analysis, especially in the field of crop improvement.     

Plastid Signals and the Bundle Sheath： Mesophyll Development in Reticulate Mutants

The development of a plant leaf is a meticulously orchestrated sequence of events producing a complex organ comprising diverse cell types. The reticulate class of leaf variegation mutants displays contrasting pigmentation between veins and interveinal regions due to specific aberrations in the development of mesophyll cells. Thus, the reticulate mutants offer a potent tool to investigate cell-type-specific developmental processes. The discovery that most mutants are affected in plastid-localized, metabolic pathways that are strongly expressed in vasculature-associated tis- sues implicates a crucial role for the bundle sheath and their chloroplasts in proper development of the mesophyll cells. Here, we review the reticulate mutants and their phenotypic characteristics, with a focus on those in Arabidopsis thali- ana. Two alternative models have been put forward to explain the relationship between plastid metabolism and meso- phyll cell development, which we call here the supply and the signaling hypotheses. We critically assess these proposed models and discuss their implications for leaf development and bundle sheath function in C3 species. The characteriza- tion of the reticulate mutants supports the significance of plastid retrograde signaling in cell development and highlights the significance of the bundle sheath in C3 photosynthesis.     

Interspecies variation in DNA damage induced by pollution

The choice of a suitable species to translate pollution signals into a quantitative monitor is a fundamental step in biomonitoring plans. Here we present the results of three years of biomonitoring at a new coal power plant in central Italy using three different aquatic and terrestrial wildlife species in order to compare their reliability as sentinel organisms for genotoxicity. The comet assay was applied to the common land snail Helix spp., the lagoon fish Aphaniusfasciatus, and the green frog Rana esculenta sampled in the area potentially exposed to the impact of the power station. The tissue concentration of some expected pollutants （As, Cd, Ni, Pb, Cr） was analysed in parallel samples collected in the same sampling sites. The three species showed different values in the comet assay （Tail Intensity） and different accumulation profiles of heavy metals. Aphanius fasciatus showed an increasing genotoxic effect over time that paralleled the temporal increase of the heavy metals, especially arsenic, and the highest correlation between heavy metals and DNA damage. Helix spp. showed levels of damage inversely related to the distance from the source of pollution and in partial accordance with the total accumulation of trace elements. On the contrary, Rana esculenta showed a low capability to accumulate metals and had inconsistent results in the comet test. The fish appeared to be the most efficient and sensitive species in detecting chemical pollution. Overall, both the fish and the snail reflected a trend of increasing pollution in the area surrounding the power plant across time and space [Current Zoology 60 （2）： 308-321, 2014].     

Heteromeric and Homomeric Geranyl Diphosphate Synthases from Catharanthus roseus and Their Role in Monoterpene Indole Alkaloid Biosynthesis

Catharanthus roseus is the sole source of two most important monoterpene indole alkaloid （MIA） anti- cancer agents： vinblastine and vincristine. MIAs possess a terpene and an indole moiety derived from terpenoid and shikimate pathways, respectively. Geranyl diphosphate （GPP）, the entry point to the formation of terpene moiety, is a product of the condensation of isopentenyl diphosphate （IPP） and dimethylallyl diphosphate （DMAPP） by GPP synthase （GPPS）. Here, we report three genes encoding proteins with sequence similarity to large subunit （CrGPPS.LSU） and small subunit （CrGPPS.SSU） of heteromeric GPPSs, and a homomeric GPPSs. CrGPPS.LSU is a bifunctional enzyme producing both GPP and geranyl geranyl diphosphate （GGPP）, CrGPPS.SSU is inactive, whereas CrGPPS is a homomeric enzyme forming GPP. Co-expression of both subunits in Escherichia coil resulted in heteromeric enzyme with enhanced activity producing only GPR While CrGPPS.LSU and CrGPPS showed higher expression in older and younger leaves, respectively, CrGPPS.SSU showed an increasing trend and decreased gradually. Methyl jasmonate （MelA） treatment of leaves sig- nificantly induced the expression of only CrGPPS.SSU. GFP localization indicated that CrGPPS.SSU is plastidial whereas CrGPPS is mitochondrial. Transient overexpression of AmGPPS.SSU in C. roseus leaves resulted in increased vindoline, immediate monomeric precursor of vinblastine and vincristine. Although C. roseus has both heteromeric and homomeric GPPS enzymes, our results implicate the involvement of only heteromeric GPPS with CrGPPS.SSU regulating the GPP flux for MIA biosynthesis.