The impact of snares on the continuity of adolescent-onset antisocial behaviour: A test of Moffitt's developmental taxonomy

Moffitt’s dual typology of ‘life-course persistent’ and ‘adolescence limited’ offending has received extensive empirical attention, but the extent to which the antisocial behaviour of adolescence limited offenders is constrained to adolescence is relatively under-examined.Using data from the Australian Mater University Study of Pregnancy and its Outcomes, we explore Moffitt’s concept of snares, or those factors that may lead to an adolescent persisting in antisocial behaviour such as drug addiction, educational failure, and contact with the justice system. The Mater University Study of Pregnancy and its Outcomes is a longitudinal study of mother–child dyads from the pre-natal stage to 21 years of age. Findings show that one-third of individuals identified as having an adolescent onset of antisocial behaviour persisted with this antisocial behaviour as young adults. This continuity can, in part, be explained by snares and the research suggests that reducing exposure to snares may lead to less antisocial behaviour in adulthood.

Genetics and the pathogenesis of ankylosing spondylitis

Purpose of review The field of genetic research in ankylosing spondylitis (AS) is advancing rapidly. The purpose of this review is to outline recent findings, particularly, in regard to genetic studies of the major histocompatibility complex (MHC) and the non-MHC genes IL23R, ERAP1, and killer cell immunologlobulin-like receptor (KIR) complex, in AS. Recent findings: Convincing evidence has been reported for the existence of further non-B27 MHC genes involved in AS. Strong, replicated association has been reported with IL23R and ERAP1 and AS. The IL23R finding strongly implicates the TH17 lymphocyte system in AS aetiopathogenesis. Suggestive evidence of a role for KIR gene polymorphism in AS exists, but definitive findings are awaited. Summary: The findings suggest that further genome-wide studies in large case-control cohorts are likely to be very productive in this disease. The IL23R findings and subsequent immunological investigations suggest that targeted intervention in the TH17 system is likely to have major therapeutic benefit, as it does in the genetically related diseases, inflammatory bowel disease and psoriasis.

Genetics of ankylosing spondylitis

Purpose of Review Over the past 3 years, several new genes and gene deserts have been identified that are associated with ankylosing spondylitis (AS). The purpose of this review is to discuss the major findings of these studies, and the answers they provide and questions they raise about the pathogenesis of this common condition. Recent Findings: Five genes/genetic regions have now definitively been associated with AS [the major histocompatibility complex (MHC), IL23R, ERAP1, 2p15 and 21q22]. Strong evidence to support association with the disease has been demonstrated for the genes IL1R2, ANTXR2, TNFSF15, TNFR1 and a region on chromosome 16q including the gene TRADD. There is an overrepresentation of genes involved in Th17 lymphocyte differentiation/activation among genes associated with AS and the related diseases inflammatory bowel disease and psoriasis, pointing strongly to this pathway as playing a major causative role in the disease. Increasing information about differential association of HLA-B27 subtypes with disease suggests a hierarchy of strength of association of those alleles with AS, providing a useful test as to the validity of different potential mechanisms of association of HLA-B27 with AS. The mechanism underlying the association of the gene deserts, 2p15 and 21q22, suggests the involvement of noncoding RNA in AS etiopathogenesis. Summary: The increasing list of genes identified as being definitely involved in AS provides a useful platform for hypothesis-driven research in the field, providing a potential alternative route to determining the underlying mechanisms involved in the disease to research focusing on HLA-B27 alone.

Genetic studies of chondrocalcinosis

Purpose of review Our understanding of the causation of the chondrocalcinosis and other disorders characterized by ectopic mineralization is rapidly increasing, and genetic studies have contributed substantially to recent major advances in the field. This review will discuss what is known about the genetics of chondrocalcinosis and what we have learned from genetic studies to date. Recent findings: Chondrocalcinosis is one of a family of conditions associated with ectopic mineralization. This family also includes disorders of mineralization of bone and spinal and other ligaments, and vascular calcification. There has been increasing evidence of the key role of transport and metabolism of inorganic pyrophosphate (PPi) in control of mineralization, and as the likely explanation for the association of a variety of genetic variants with chondrocalcinosis and ectopic mineralization elsewhere. This may be an overly simplistic view of this family of conditions, with recent evidence suggesting that, for example, ANKH variants may not all predispose to chondrocalcinosis by effects on PPi transport, but may also influence chondrocyte maturation. Summary: Understanding the control of the process of mineralization and its tissue specificity are important steps in the search for rational therapies for these conditions.

Proximinality in Banach spaces

In this paper, we study approximatively τ-compact and τ-strongly Chebyshev sets, where τ is the norm or the weak topology. We show that the metric projection onto τ-strongly Chebyshev sets are norm-τ continuous. We characterize approximatively τ-compact and τ-strongly Chebyshev hyperplanes and use them to characterize factor reflexive proximinal subspaces in τ-almost locally uniformly rotund spaces. We also prove some stability results on approximatively τ-compact and τ-strongly Chebyshev subspaces.

Äldres upplevelser av att flytta till ett servicehus

Mänga äldre är med om en förändring i deras hemmiljö. Ofta sker denna förändring dä den äldre inte klarar av att bo hemma längre. Jag är intresserad av hur äldre upplever denna förändring och om flytten päverkar känslan av att anpassa sig till ett nytt hem. Jag är ocksä intresserad av att undersöka vad den omgivande miljön betyder för den äldre och om hurudana känslor ett miljöombyte väcker hos den äldre. Jag har undersökt detta genom att halla en diskussionsgrupp för äldre som bor pä det finskspräkiga, kommunala servicehuset i Östra centrum. Diskussionsgruppen träffades en gang i veckan under en tidsperiod pä tvä mänader. Fyra äldre deltog aktivt i diskussionsgruppen. Som forskningsmetod har jag använt mig av narrativa livsberättelser. Jag bad de äldre i diskussionsgruppen om skrivna livsberättelser. Som forskningsmaterial användes dessutom de äldres skrivna dikter och tankar, bade nya men också gamla texter. Jag använde mig av narrativ analys enligt det paradigmatiska tänkandet. Jag farm sex olika huvudteman i mitt material: hemmets betydelse, miljöns betydelse, upplevelsen av att flytta till ett servicehus, sociala samverkan, värden och upplevelsen av älderdom. De äldre i min undersökning uppgav att miljöns betydelse hade ökat för dem efter att de flyttade tili servicehuset. De äldre uppskattade särskilt känslan av lugn och stillhet dä de vistades ute i naturen. Hemmets betydelse hade däremot sjunkit totalt. Ingen av de äldre uppgav lägenheten pä servicehuset vara ett hem för dem, utan främst använde de ordet rum. Upplevelsen av att flytta tili servicehuset hade för dem flesta i diskussionsgruppen värit positiv. Det som de äldre uppgav att de längtade mest efter pä servicehuset handlade förutom smä konkreta saker främst om dagliga hemsysslor. De äldre kände sig ocksä ensamma och en orsak tili detta var att den sociala samverkan uppgavs vara mycket fattig pä servicehuset. De viktigaste kalloina som jag har använt i denna undersökning är doktorsavhandlingarna av Anni Vilkko, Omaelämänkerta kohtaamispaikkana. Naisen elämän kerronta ja luenta (1997) och Annukka Klemola, Omasta kodista hoitokotiin. Etnografia keskipohjalaisten vanhusten siirtymävaiheesta (2006). Jag har ocksä utgått från Sinikka Hakonens Kirjoittaminen merkityksellistää elämää (2003).

Äldres upplevelser av att flytta till ett servicehus

Många äldre är med om en förändring i deras hemmiljö. Ofta sker denna förändring då den äldre inte klarar av att bo hemma längre. Jag är intresserad av hur äldre upplever denna förändring och om flytten påverkar känslan av att anpassa sig till ett nytt hem. Jag är också intresserad av att undersöka vad den omgivande miljön betyder för den äldre och om hurudana känslor ett miljöombyte väcker hos den äldre. Jag har undersökt detta genom att hålla en diskussionsgrupp för äldre som bor på det finskspråkiga, kommunala servicehuset i Östra centrum. Diskussionsgruppen träffades en gång i veckan under en tidsperiod på två månader. Fyra äldre deltog aktivt i diskussionsgruppen. Som forskningsmetod har jag använt mig av narrativa livsberättelser. Jag bad de äldre i diskussionsgruppen om skrivna livsberättelser. Som forskningsmaterial användes dessutom de äldres skrivna dikter och tankar, både nya men också gamla texter. Jag använde mig av narrativ analys enligt det paradigmatiska tänkandet. Jag fann sex olika huvudteman i mitt material: hemmets betydelse, miljöns betydelse, upplevelsen av att flytta till ett servicehus, sociala samverkan, vården och upplevelsen av ålderdom. De äldre i min undersökning uppgav att miljöns betydelse hade ökat för dem efter att de flyttade till servicehuset. De äldre uppskattade särskilt känslan av lugn och stillhet då de vistades ute i naturen. Hemmets betydelse hade däremot sjunkit totalt. Ingen av de äldre uppgav lägenheten på servicehuset vara ett hem för dem, utan främst använde de ordet rum. Upplevelsen av att flytta till servicehuset hade för dem flesta i diskussionsgruppen varit positiv. Det som de äldre uppgav att de längtade mest efter på servicehuset handlade förutom små konkreta saker främst om dagliga hemsysslor. De äldre kände sig också ensamma och en orsak till detta var att den sociala samverkan uppgavs vara mycket fattig på servicehuset. De viktigaste källorna som jag har använt i denna undersökning är doktorsavhandlingarna av Anni Vilkko, Omaelämänkerta kohtaamispaikkana. Naisen elämän kerronta ja luenta (1997) och Annukka Klemola, Omasta kodista hoitokotiin. Etnografia keskipohjalaisten vanhusten siirtymävaiheesta (2006). Jag har också utgått från Sinikka Hakonens Kirjoittaminen merkityksellistää elämää (2003).

Äldres upplevelser av att flytta till ett servicehus

Många äldre är med om en förändring i deras hemmiljö. Ofta sker denna förändring då den äldre inte klarar av att bo hemma längre. Jag är intresserad av hur äldre upplever denna förändring och om flytten påverkar känslan av att anpassa sig till ett nytt hem. Jag är också intresserad av att undersöka vad den omgivande miljön betyder för den äldre och om hurudana känslor ett miljöombyte väcker hos den äldre. Jag har undersökt detta genom att hålla en diskussionsgrupp för äldre som bor på det finskspråkiga, kommunala servicehuset i Östra centrum. Diskussionsgruppen träffades en gång i veckan under en tidsperiod på två månader. Fyra äldre deltog aktivt i diskussionsgruppen. Som forskningsmetod har jag använt mig av narrativa livsberättelser. Jag bad de äldre i diskussionsgruppen om skrivna livsberättelser. Som forskningsmaterial användes dessutom de äldres skrivna dikter och tankar, både nya men också gamla texter. Jag använde mig av narrativ analys enligt det paradigmatiska tänkandet. Jag fann sex olika huvudteman i mitt material: hemmets betydelse, miljöns betydelse, upplevelsen av att flytta till ett servicehus, sociala samverkan, vården och upplevelsen av ålderdom. De äldre i min undersökning uppgav att miljöns betydelse hade ökat för dem efter att de flyttade till servicehuset. De äldre uppskattade särskilt känslan av lugn och stillhet då de vistades ute i naturen. Hemmets betydelse hade däremot sjunkit totalt. Ingen av de äldre uppgav lägenheten på servicehuset vara ett hem för dem, utan främst använde de ordet rum. Upplevelsen av att flytta till servicehuset hade för dem flesta i diskussionsgruppen varit positiv. Det som de äldre uppgav att de längtade mest efter på servicehuset handlade förutom små konkreta saker främst om dagliga hemsysslor. De äldre kände sig också ensamma och en orsak till detta var att den sociala samverkan uppgavs vara mycket fattig på servicehuset. De viktigaste källorna som jag har använt i denna undersökning är doktorsavhandlingarna av Anni Vilkko, Omaelämänkerta kohtaamispaikkana. Naisen elämän kerronta ja luenta (1997) och Annukka Klemola, Omasta kodista hoitokotiin. Etnografia keskipohjalaisten vanhusten siirtymävaiheesta (2006). Jag har också utgått från Sinikka Hakonens Kirjoittaminen merkityksellistää elämää (2003).

Right-Definite Multiparameter Sturm–Liouville Problems With Eigenparameter-Dependent Boundary Conditions

We study a system of ordinary differential equations linked by parameters and subject to boundary conditions depending on parameters. We assume certain definiteness conditions on the coefficient functions and on the boundary conditions that yield, in the corresponding abstract setting, a right-definite case. We give results on location of the eigenvalues and oscillation of the eigenfunctions.

Txina da. Exposición colectiva

[ES]La revolución económica y social que supone el mundo globalizado tiene también una dimensión cultural. Y en el espacio de eso que se está denominando “países emergentes” la cultura representa un hervidero de ideas, experiencias y propuestas estéticas. Hoy no es posible ignorar, dentro del panorama artístico, lo que ocurre en esos países. Se trata, muy al contrario, de un foco de interés que conviene atender, y donde nuestros artistas pueden encontrar un nuevo territorio, físico y mental, para desarrollar su particular investigación estética. La presente exposición es una buena muestra del impacto que ha supuesto este proyecto. Y es también, al mismo tiempo, una oportunidad para que nosotros y nosotras podamos disfrutar de las propuestas creativas alumbradas en las cuatro ediciones del programa.

Advanced Reaction Systems for Hydrogen Production

[EN] This PhD work started in March 2010 with the support of the University of the Basque Country (UPV/EHU) under the program named “Formación de Personal Investigador” at the Chemical and Environmental Engineering Department in the Faculty of Engineering of Bilbao. The major part of the Thesis work was carried out in the mentioned department, as a member of the Sustainable Process Engineering (SuPrEn) research group. In addition, this PhD Thesis includes the research work developed during a period of 6 months at the Institut für Mikrotechnik Mainz GmbH, IMM, in Germany. During the four years of the Thesis, conventional and microreactor systems were tested for several feedstocks renewable and non-renewable, gases and liquids through several reforming processes in order to produce hydrogen. For this purpose, new catalytic formulations which showed high activity, selectivity and stability were design. As a consequence, the PhD work performed allowed the publication of seven scientific articles in peer-reviewed journals. This PhD Thesis is divided into the following six chapters described below. The opportunity of this work is established on the basis of the transition period needed for moving from a petroleum based energy system to a renewable based new one. Consequently, the present global energy scenario was detailed in Chapter 1, and the role of hydrogen as a real alternative in the future energy system was justified based on several outlooks. Therefore, renewable and non-renewable hydrogen production routes were presented, explaining the corresponding benefits and drawbacks. Then, the raw materials used in this Thesis work were described and the most important issues regarding the processes and the characteristics of the catalytic formulations were explained. The introduction chapter finishes by introducing the concepts of decentralized production and process intensification with the use of microreactors. In addition, a small description of these innovative reaction systems and the benefits that entailed their use were also mentioned. In Chapter 2 the main objectives of this Thesis work are summarized. The development of advanced reaction systems for hydrogen rich mixtures production is the main objective. In addition, the use and comparison between two different reaction systems, (fixed bed reactor (FBR) and microreactor), the processing of renewable raw materials, the development of new, active, selective and stable catalytic formulations, and the optimization of the operating conditions were also established as additional partial objectives. Methane and natural gas (NG) steam reforming experimental results obtained when operated with microreactor and FBR systems are presented in Chapter 3. For these experiments nickel-based (Ni/Al2O3 and Ni/MgO) and noble metal-based (Pd/Al2O3 and Pt/Al2O3) catalysts were prepared by wet impregnation and their catalytic activity was measured at several temperatures, from 973 to 1073 K, different S/C ratios, from 1.0 to 2.0, and atmospheric pressure. The Weight Hourly Space Velocity (WHSV) was maintained constant in order to compare the catalytic activity in both reaction systems. The results obtained showed a better performance of the catalysts operating in microreactors. The Ni/MgO catalyst reached the highest hydrogen production yield at 1073 K and steam-to-carbon ratio (S/C) of 1.5 under Steam methane Reforming (SMR) conditions. In addition, this catalyst also showed good activity and stability under NG reforming at S/C=1.0 and 2.0. The Ni/Al2O3 catalyst also showed high activity and good stability and it was the catalyst reaching the highest methane conversion (72.9 %) and H2out/CH4in ratio (2.4) under SMR conditions at 1073 K and S/C=1.0. However, this catalyst suffered from deactivation when it was tested under NG reforming conditions. Regarding the activity measurements carried out with the noble metal-based catalysts in the microreactor systems, they suffered a very quick deactivation, probably because of the effects attributed to carbon deposition, which was detected by Scanning Electron Microscope (SEM). When the FBR was used no catalytic activity was measured with the catalysts under investigation, probably because they were operated at the same WHSV than the microreactors and these WHSVs were too high for FBR system. In Chapter 4 biogas reforming processes were studied. This chapter starts with an introduction explaining the properties of the biogas and the main production routes. Then, the experimental procedure carried out is detailed giving concrete information about the experimental set-up, defining the parameters measured, specifying the characteristics of the reactors used and describing the characterization techniques utilized. Each following section describes the results obtained from activity testing with the different catalysts prepared, which is subsequently summarized: Section 4.3: Biogas reforming processes using γ-Al2O3 based catalysts The activity results obtained by several Ni-based catalysts and a bimetallic Rh-Ni catalyst supported on magnesia or alumina modified with oxides like CeO2 and ZrO2 are presented in this section. In addition, an alumina-based commercial catalyst was tested in order to compare the activity results measured. Four different biogas reforming processes were studied using a FBR: dry reforming (DR), biogas steam reforming (BSR), biogas oxidative reforming (BOR) and tri-reforming (TR). For the BSR process different steam to carbon ratios (S/C) from 1.0 to 3.0, were tested. In the case of BOR process the oxygen-to-methane (O2/CH4) ratio was varied from 0.125 to 0.50. Finally, for TR processes different S/C ratios from 1.0 to 3.0, and O2/CH4 ratios of 0.25 and 0.50 were studied. Then, the catalysts which achieved high activity and stability were impregnated in a microreactor to explore the viability of process intensification. The operation with microreactors was carried out under the best experimental conditions measured in the FBR. In addition, the physicochemical characterization of the fresh and spent catalysts was carried out by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), N2 physisorption, H2 chemisorption, Temperature Programmed Reduction (TPR), SEM, X-ray Photoelectron Spectroscopy (XPS) and X-ray powder Diffraction (XRD). Operating with the FBR, conversions close to the ones predicted by thermodynamic calculations were obtained by most of the catalysts tested. The Rh-Ni/Ce-Al2O3 catalyst obtained the highest hydrogen production yield in DR. In BSR process, the Ni/Ce-Al2O3 catalyst achieved the best activity results operating at S/C=1.0. In the case of BOR process, the Ni/Ce-Zr-Al2O3 catalyst showed the highest reactants conversion values operating at O2/CH4=0.25. Finally, in the TR process the Rh-Ni/Ce-Al2O3 catalyst obtained the best results operating at S/C=1.0 and O2/CH4=0.25. Therefore, these three catalysts were selected to be coated onto microchannels in order to test its performance under BOR and TR processes conditions. Although the operation using microreactors was carried out under considerably higher WHSV, similar conversions and yields as the ones measured in FBR were measured. Furthermore, attending to other measurements like Turnover Frequency (TOF) and Hydrogen Productivity (PROD), the values calculated for the catalysts tested in microreactors were one order of magnitude higher. Thus, due to the low dispersion degree measured by H2-chemisorption, the Ni/Ce-Al2O3 catalyst reached the highest TOF and PROD values. Section 4.4: Biogas reforming processes using Zeolites L based catalysts In this section three type of L zeolites, with different morphology and size, were synthesized and used as catalyst support. Then, for each type of L zeolite three nickel monometallic and their homologous Rh-Ni bimetallic catalysts were prepared by the wetness impregnation method. These catalysts were tested using the FBR under DR process and different conditions of BSR (S/C ratio of 1.0 and 2.0), BOR (O2/CH4 ratio of 0.25 and 0.50) and TR processes (at S/C=1.0 and O2/CH4=0.25). The characterization of these catalysts was also carried out by using the same techniques mentioned in the previous section. Very high methane and carbon dioxide conversion values were measured for almost all the catalysts under investigation. The experimental results evidenced the better catalytic behavior of the bimetallic catalysts as compared to the monometallic ones. Comparing the catalysts behavior with regards to their morphology, for the BSR process the Disc catalysts were the most active ones at the lowest S/C ratio tested. On the contrary, the Cylindrical (30–60 nm) catalysts were more active under BOR conditions at O2/CH4=0.25 and TR processes. By the contrary, the Cylindrical (1–3 µm) catalysts showed the worst activity results for both processes. Section 4.5: Biogas reforming processes using Na+ and Cs+ doped Zeolites LTL based catalysts A method for the synthesis of Linde Type L (LTL) zeolite under microwave-assisted hydrothermal conditions and its behavior as a support for heterogeneously catalyzed hydrogen production is described in this section. Then, rhodium and nickel-based bimetallic catalysts were prepared in order to be tested by DR process and BOR process at O2/CH4=0.25. Moreover, the characterization of the catalysts under investigation was also carried out. Higher activities were achieved by the catalysts prepared from the non-doped zeolites, Rh-Ni/D and Rh-Ni/N, as compared to the ones supported on Na+ and Cs+ exchanged supports. However, the differences between them were not very significant. In addition, the Na+ and Cs+ incorporation affected mainly to the Disc catalysts. Comparing the results obtained by these catalysts with the ones studied in the section 4.4, in general worst results were achieved under DR conditions and almost the same results when operated under BOR conditions. In Chapter 5 the ethylene glycol (EG) as feed for syngas production by steam reforming (SR) and oxidative steam reforming (OSR) was studied by using microchannel reactors. The product composition was determined at a S/C of 4.0, reaction temperatures between 625°C and 725°C, atmospheric pressure and Volume Hourly Space Velocities (VHSV) between 100 and 300 NL/(gcath). This work was divided in two sections. The first one corresponds to the introduction of the main and most promising EG production routes. Then, the new experimental procedure is detailed and the information about the experimental set-up and the measured parameters is described. The characterization was carried out using the same techniques as for the previous chapter. Then, the next sections correspond to the catalytic activity and catalysts characterization results. Section 5.3: xRh-cm and xRh-np catalysts for ethylene glycol reforming Initially, catalysts with different rhodium loading, from 1.0 to 5.0 wt. %, and supported on α-Al2O3 were prepared by two different preparation methods (conventional impregnation and separate nanoparticle synthesis). Then, the catalysts were compared regarding their measured activity and selectivity, as well as the characterization results obtained before and after the activity tests carried out. The samples prepared by a conventional impregnation method showed generally higher activity compared to catalysts prepared from Rh nanoparticles. By-product formation of species such as acetaldehyde, ethane and ethylene was detected, regardless if oxygen was added to the feed or not. Among the catalysts tested, the 2.5Rh-cm catalyst was considered the best one. Section 5.4: 2.5Rh-cm catalyst support modification with CeO2 and La2O3 In this part of the Chapter 5, the catalyst showing the best performance in the previous section, the 2.5Rh-Al2O3 catalyst, was selected in order to be improved. Therefore, new Rh based catalysts were designed using α-Al2O3 and being modified this support with different contents of CeO2 or La2O3 oxides. All the catalysts containing additives showed complete conversion and selectivities close to the equilibrium in both SR and OSR processes. In addition, for these catalysts the concentrations measured for the C2H4, CH4, CH3CHO and C2H6 by-products were very low. Finally, the 2.5Rh-20Ce catalyst was selected according to its catalytic activity and characterization results in order to run a stability test, which lasted more than 115 hours under stable operation. The last chapter, Chapter 6, summarizes the main conclusions achieved throughout this Thesis work. Although very high reactant conversions and rich hydrogen mixtures were obtained using a fixed bed reaction system, the use of microreactors improves the key issues, heat and mass transfer limitations, through which the reforming reactions are intensified. Therefore, they seem to be a very interesting and promising alternative for process intensification and decentralized production for remote application.

植物克隆性在生态修复中的意义：鄂尔多斯高原赖草和沙鞭的案例

克隆植物通过克隆生长能够很好的适应异质性的生境。在进行植被修复的研究和实践中，注意发扬或引进具有重要资源价值的克隆植物是重要的恢复生态学思考和途径。本文主要应用实验生态学的方法，通过对鄂尔多斯高原不同克隆植物克隆性及其对水分条件的反应的比较，以及对不同克隆植物抵抗风蚀和风蚀坑修复的能力的比较，探讨克隆植物对干旱(水分条件)及风蚀的适应机制，从而对克隆植物的克隆性在生态修复中的意义进行了研究和阐述。 　　对不同水分条件下赖草(Leymus secalinus (Georgi.) Tzvel)和沙鞭(Psammochloa villosa (Trin.) Bor)克隆性的研究表明：克隆生长开始时间和克隆生长率二者与克隆植物新产生子代分株数量之间存在着显著的相关关系，说明克隆生长开始时间和克隆生长率能够作为准确评价克隆性的指标;相对于沙鞭来说，赖草具有更强的克隆性，表现在它的早的克隆生长开始时间、高的克隆生长率，并且这种差异可以被水分条件所修饰;植物的克隆性对水分条件具有较强的可塑性，这种可塑性具有种间差异。相对赖草来说，沙鞭能更好地适应干旱条件。 　　克隆植物植株有两种繁殖体类型，分株和种子。本研究对分别从分株来源和种子来源的赖草与沙鞭植株在不同水分条件下生长状况及克隆性进行了比较，结果表明：水分的增加，有利于赖草的生长;而对于沙鞭来说，水分抑制了分株来源的沙鞭植株的生长，但对种子来源的沙鞭植株的生长有着促进作用。克隆植物的克隆性在水分条件较好的情况下能够得到更好的表达。不同来源有赖草植株之间克隆性没有明显差异;对于沙鞭来说，分株来源的沙鞭植株克隆性受水分条件的影响不明显，但水分有利于种子来源的沙鞭植株克隆性的表达。说明不同繁殖体类型来源的植株，克隆性对水分的反应格局存在着一定的差异。分株来源的沙鞭植株对干旱条件具有比种子来源的植株更强的适应性。 　　通过对沙鞭和赖草实生幼苗在不同风蚀程度下生长状况的比较，结果表明二者幼苗在抵抗风蚀时采取不同的策略。风蚀显著降低了赖草产生新生分株的能力，而对沙鞭潜在分株数没有显著影响。赖草实生幼苗生长状况在轻中度风蚀条件下与对照处理没有显著差异，说明对风蚀具有较强的抵抗能力，其策略可能是风险分担，赖草具有的强克隆性使之能快速产生新的子代分株，从而分担了风蚀造成的风险;沙鞭实生幼苗的生长状况受风蚀影响较为明显，但风蚀没有能对其产生潜在分株(芽)的能力产生显著的影响，说明沙鞭实生幼苗对风蚀可能采取的是通过芽的产生贮存资源、逃避风险、等待机会的策略。赖草和沙鞭对风蚀所采用的不同适应策略，可能会影响到二者在自然条件下种群更新方式的选择。 　　为了探讨克隆植物对风蚀坑修复能力及机理，研究了沙鞭和赖草对种群内风蚀坑的修复过程，结果表明：合轴型克隆草本赖草具有比单轴型克隆草本沙鞭更强的植被修复能力，能够在风蚀坑中产生更多的新生分株，这主要归功于赖草的强克隆性，而赖草间隔子的可塑性反应也有利于将更多的新生分株放置在风蚀坑内。二者进行植被修复的机理有所差异，赖草对风蚀坑的修复主要是通过周围根茎扩展进入坑中，然后产生新的分株;而沙鞭不仅可以通过周边根茎进入产生新的分株，同时也可以通过刺激深层休眠芽来产生新的分株。二者都能在风蚀坑中产生比自然条件下更多的分株，以更好利用风蚀坑中充足的光照;但同时这些分株的生长也受到风蚀坑中养分条件的制约，生物量和生长状况都不如自然条件下形成的分株。 　　 　　

浑善达克沙地根茎克隆植物对去除枝叶的响应

过度放牧是导致浑善达克沙地荒漠化发展的重要原因之一。在该地区占据优势的根茎型克隆草本植物不仅被牲畜频繁地采食，而且也面临着频繁的沙埋和养分胁迫的干扰。通过克隆生长，这些根茎型植物的单个基株能够跨越异质性的资源斑块，同时也可能遭受局部的、非均匀性的采食或沙埋。克隆整合可能会作为一种补偿性机制促进被采食克隆部分或分株的恢复和生长，因而，能够缓解采食及其与环境因素（沙埋/养分胁迫）交互作用对克隆植物的影响。本文以浑善达克沙地草地典型的根茎型沙生植物种和草地植物种为实验材料，应用（野外和温室）实验生态学方法检验了克隆整合的这种效果。 在一个野外实验中，通过对共存在沙丘上的两种根茎型克隆植物沙地雀麦（Bromus ircutensis Kom.）和沙鞭（Psammochloa villosa (Trin.) Bor.），及两种非克隆植物褐沙蒿（Artemisia intramongolica H.C.Fu）和草木樨状黄芪（Astragalus melilotoides Pall.）的个体植株进行不同强度（0、50、90％）的枝叶去除处理，我们发现：50％和90％的枝叶去除增加了沙地雀麦和沙鞭的相对生长率（RGR）;而90％的枝叶去除显著减小了褐沙蒿和草木樨状黄芪的RGR。经两个多月处理后，与对照相比，去除枝叶的非克隆植物的地上生物量恢复的远不及克隆植物完全。这些结果表明克隆植物比共存的非克隆植物更能忍耐采食。在分株种群水平上开展的另外一个野外实验表明，在50％的去除强度下，根茎连接明显改善了沙鞭分株种群的表现，但对沙地雀麦分株种群没有显著影响。然而，在90％的去除强度下，根茎连接显著的改善了两种植物分株种群的表现，显示出克隆整合的重要作用。而且，与未剪除的分株种群相比，两种植物当遭受90％的去除强度后，其根茎保持连接的分株种群产生了更多而小的分株个体。 以羊草（Leymus chinensis (Trin.) Tzevl.）和赖草（Leymus secalinus (Georgi) Tzvel）的克隆片断为材料，通过两个温室实验研究了克隆整合对克隆植物忍受采食与沙埋/养分胁迫交互作用的影响。每个克隆片断由一个近端（发育上较老）分株和一个远端（发育上较年轻）分株组成。近端分株不进行胁迫处理，而远端分株进行重复去除 枝叶沙埋/养分胁迫处理;同时，切断或保持克隆片断的根茎连接。结果表明，单因素的干扰对两个种远端分株的影响较小。当遭受剪除处理后，低养供应的赖草远端分株显示出比高养条件下更强的生物量补偿能力。当两个种的远 端分株处于单因素胁迫时，根茎切断很少影响其生物量生产和新分株的形成;而当远端分株同时处于枝叶去除和沙 埋/养分胁迫下时，切断根茎对两个种远端分株的生物量和分株的产生造成了明显的负效果，表明克隆整合发挥了重 要的作用。但克隆整合并没有导致近端分株的显著损耗。 基于以上实验结果，我们得出：克隆整合可以明显提高浑善达克沙地根茎克隆植物应对枝叶去除，及其和沙埋/养分胁迫交互影响的能力，是克隆植物适应频繁干扰的沙地草地环境的重要对策之一。

Ⅰ 虎杖聚酮类化合物生物合成相关基因的克隆及功能分析 Ⅱ 高山红景天酪醇生物合成代谢途径机制分析

Ⅰ 虎杖聚酮类化合物生物合成相关基因的克隆及功能分析 虎杖 (Polygonum cuspidatum Sieb. et Zucc) 属于蓼科蓼属多年生草本植物，在中国和日本民间曾被广泛用于动脉粥样硬化、高血压、咳嗽、化脓性皮肤炎以及淋病的治疗，具有祛风利湿、散瘀定痛、止咳化痰等功效。而在现代医学上最令人瞩目和具有发展前景的是其在抗肿瘤、心血管保护、抗氧化方面的作用，相关疗效主要来自于虎杖中结构迥异、种类丰富的聚酮化合物及其衍生物资源。这些聚酮类化合物主要包括蒽醌、大黄素、大黄素-甲醚、大黄酚、芪类以及类黄酮化合物等。其中，大部分聚酮类化合物生物合成途径机制尚不明确，但可以肯定的是植物类型III聚酮合酶type III polyketide synthases (PKSs) 在这些聚酮化合物的生物合成起始反应中行使着关键的作用。因此，除了我们所熟悉的类黄酮化合物、芪类化合物之外，进一步分离和分析虎杖中其它重要聚酮类化合物生物合成所涉及的类型III聚酮合酶基因的是非常值得期待的。 目前，已经有14个植物类型III PKS基因被克隆和功能分析。植物类型III PKS的共同特征包括基因结构、序列相似性、保守的活性中心、酶学性质以及共同的催化机制等。显花植物（裸子植物和被子植物）中，植物类型III PKS的基因结构绝对保守，除了一个早期报道的金鱼草（Antirrhinum majus）查尔酮合酶chalcone synthase (CHS) 含有第二个内含子外，迄今为止所有已知的植物类型III PKS基因均含有一个内含子且该内含子位置保守。有趣的是，在本研究中，两个含有3个内含子的类型III PKS基因从虎杖中被分离，且两个基因3个内含子的位置完全保守，这是三内含子类型III PKS基因首次得到分离。除了新奇的基因结构外，体外功能分析显示上述两个基因还具有特殊的酶学性质和功能。 本论文围绕上述2个三内含子基因开展了以下工作： 虎杖中一个由三内含子基因编码的新型类型III聚酮合酶 一个类型III PKS的cDNA及其相应的基因（PcPKS2）从药用植物虎杖中被克隆。序列分析结果表明，PcPKS2的开放阅读框被3个内含子分隔，这是一个出人意料的发现，因为截至到目前为止，除了金鱼草一个CHS基因外，所有已知的类型III PKS基因均在固定位置上含有一个内含子。除了特殊的基因结构外，PcPKS2显示了一些有趣的特性：(i) CHS“守卫”苯丙氨酸——Phe215和Phe265在PcPKS2中双双缺失，它们分别被亮氨酸和半胱氨酸取代;(ii) 体外功能分析结果表明，当酶促反应体系的pH值为6.5-8.5时，大肠杆菌中过表达的重组PcPKS2高效地合成丁烯酮非环化产物——4-香豆酰甘油酸内酯（4-coumaroyltriacetic acid lactone (CTAL)）为主产物，而丙烯酮非环化产物bis-noryangonin (BNY) 以及苯亚甲基丙酮为副产物;而当酶促反应体系的pH值为9.0时，PcPKS2高效地合成苯亚甲基丙酮为主产物，而CTAL、BNY为副产物。另外，除了上述3种产物外，在不同的pH条件下，还有痕量的柚皮素查尔酮能被检测到。此外，在4-香豆酰辅酶A（4-coumaroyl-CoA）的类似化合物中，除了4-香豆酰辅酶A外，只有feruloyl-CoA能够被PcPKS2接受作为起始底物。PcPKS2不接受脂肪酰辅酶A——异丁酰基辅酶A（isobutyryl-CoA）、异戊酰基辅酶A（isovaleryl-CoA）以及乙酰辅酶A（acetyl-CoA）作为起始底物。Southern blot杂交结果表明，在虎杖基因组中存在2-4个PcPKS2基因的拷贝。Northern blot杂交结果表明，在根茎和幼叶中，PcPKS2表达量很高，而在根中无表达。叶中的PcPKS2的表达受病原菌诱导，但不受伤诱导。 虎杖中一个编码双功能类型III聚酮合酶的三内含子基因的鉴定 显花植物中，所有已知的类型III PKS 基因均含有一个内含子且位置绝对保守。本研究中，综合运用PCR技术，从富含聚酮类化合物的植物虎杖中克隆得到一个类型III PKS 基因（PcPKS1）及其cDNA。序列分析结果表明，PcPKS1含有3个内含子。系统发育分析结果表明，PcPKS1与其它植物的CHSs归为一类。然而，体外功能分析结果表明，当酶促反应体系pH值为7.0时，大肠杆菌中过表达的重组PcPKS1高效地合成柚皮素查尔酮（naringenin）为单一产物;而当pH值为9.0时，苯亚甲基丙酮（p-hydroxybenzalacetone）几乎为重组PcPKS1的唯一产物。后续的研究表明，与典型的CHSs相比，PcPKS1具有另外一些不同的特点：在pH值为9.0时（PcPKS1的苯亚甲基丙酮合成活性最适pH值），在4-香豆酰辅酶A的类似化合物中，只有feruloyl-CoA能够被PcPKS1接受作为起始底物。与CHSs展现出的对脂肪酰辅酶A宽泛的底物特异性不同，在不同的pH条件下，PcPKS1不接受异丁酰基辅酶A（isobutyryl-CoA）、异戊酰基辅酶A（isovaleryl-CoA）以及乙酰辅酶A（acetyl-CoA）作为起始底物。以上数据指出重组PcPKS1是一个具有查尔酮合酶（CHS）和苯亚甲基丙酮合酶（BAS）活性的双功能酶。Southern blot杂交结果表明，在虎杖基因组中存在2-4个PcPKS1基因的拷贝。Northern blot杂交结果表明，PcPKS1可能在防御病原菌和草食动物方面起着重要作用。PcPKS1和PcPKS2共同从虎杖中被分离的事实极有可能暗示了苯丁烷类化合物（phenylbutanoid）及其衍生物存在于虎杖中。 Ⅱ 高山红景天酪醇生物合成代谢途径机制研究 高山红景天（Rhodiola sachalinensis A. Bor）是景天科（Crassulaceae）红景天属多年生草本植物，作为一种适应原性中草药在中国的应用史已经超过800年。最近红景天提取物作为一种重要的商业药用制剂资源，其应用遍及欧洲、亚洲和美国，其主要治疗范围包括抗变应性和消炎，提高心理机敏性等。目前已经非常明确，红景天甙（salidroside）和甙元酪醇（tyrosol）是红景天属植物的主要功效成分，主要分布于这类植物的根中并且具有抗缺氧、抗疲劳、延缓衰老、预防紫外线辐射伤害等功效。红景天甙为酪醇8-O-β-D葡萄糖甙，是酪醇在葡萄糖基转移酶UDP-glucosyltransferase (UGT) 的催化下糖基化后形成的，可以认为是酪醇在植物体内的贮存形式。酪醇作为一种重要的活性分子，同样存在于橄榄树和葡萄酒中。 虽然已经非常明确酪醇来自于莽草酸代谢途径，然而其具体的生物合成途径及其调控仍不明确。总结以往的报道，在酪醇的生物合成上主要存在两种观点：一是酪醇可能来自于苯丙烷代谢途径产生的4-香豆酸（4-coumaric acid）前体;二是来自于酪氨酸的酪胺（tyramine）可能是酪醇生物合成的直接前体。我们的工作兴趣主要围绕着鉴别高山红景天中的酪醇生物合成途径展开： 高山红景天内源苯丙氨酸解氨酶PALrs1的过表达对红景天甙积累的影响 红景天甙是来自于药用植物高山红景天的一种适应原性新型药物，其生物合成途径可能起始于苯丙氨酸或酪氨酸。由于高山红景天野生植物资源的匮乏和相对含量很低，阐明红景天甙的生物合成途径对于增加红景天甙的供给至关重要。在我们以前的工作中，运用cDNA末端快速扩增技术（RACE），一个编码苯丙氨酸解氨酶phenylalanine ammonia-lyase (PAL)的cDNA从高山红景天中被克隆，命名为PALrs1。在本研究中，PALrs1置于35S启动子+Ω增强子序列的控制下通过农杆菌（Agrobacterium tumefaciens）介导法转化回高山红景天。PCR 和 PCR–Southern blot分析结果表明，PALrs1已经整合到了转基因植物的基因组上。Northern blot杂交结果表明，PALrs1已经获得在转录水平上的高水平表达。与预期的结果相同，高效液相色谱High-performance liquid chromatography (HPLC)测定结果显示PALrs1的过表达引起4-香豆酸含量增长3.3倍。然而，与之相反的是，酪醇和红景天甙含量与对照相比反而分别下降4.7和7.7倍。此外，我们发现PALrs1的过表达造成酪氨酸含量下降2.6倍。这些数据暗示着PALrs1的过表达和4-香豆酸的积累并不能促进酪醇的生物合成。酪醇，作为一种苯乙烷类衍生物并非来自苯丙氨酸，而酪氨酸含量的下降则极有可能是酪醇生物合成和红景天甙积累大规模下降的直接原因。