Purification and characterization of mouse soluble receptor for advanced glycation end products (sRAGE)

The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface proteins that has been implicated as a progression factor in a number of pathologic conditions from chronic inflammation to cancer to Alzheimer's disease. In such conditions, RAGE acts to facilitate pathogenic processes. Its secreted isoform, soluble RAGE or sRAGE, has the ability to prevent RAGE signaling by acting as a decoy. sRAGE has been used successfully in animal models of a range of diseases to antagonize RAGE-mediated pathologic processes. In humans, sRAGE results from alternative splicing of RAGE mRNA. This study was aimed to determine whether the same holds true for mouse sRAGE and, in addition, to biochemically characterize mouse sRAGE. The biochemical characteristics examined include glycosylation and disulfide patterns. In addition, sRAGE was found to bind heparin, which may mediate its distribution in the extracellular matrix and cell surfaces of tissues. Finally, our data indicated that sRAGE in the mouse is likely produced by carboxyl-terminal truncation, in contrast to the alternative splicing mechanism reported in humans.     

Effect of Cullural Conditions on the Growth of Agrostemma githago Cells in Suspension Culture and the Concomitant Production of an Anti-Plant Virus Substance

An extract of cultured Agroxieinma githago L. cells was found to show potent inhibitory activity against plans virus infection. The effects of cultural conditions on the growth of the cell suspension and on the production of the inhibitor were examined. Since the production of substance was dependent on growth. experiments were made to improve growth. The optimum temperature was 26 to 30°C and optimum pH of the medium before autoclaving was between 5 and 7. In a medium of higher osmotic pressure, the water content of the cultured cells was lowered markedly. The growth rate in a small volume of the medium was higher than that in a larger volume at an early stage of the cultivation, but it was not changed by different inoculum sizes. The cells required thiamine and 2,4-D for growth but no other vitamins or growth regulators. The optimum level of 2,4-D was 0.1 mg/l. Higher sucrose concentration in the medium gave higher production of cell mass and of the inhibitor. However, 3% of sucrose was selected as the most economical concentration. For normal cell growth, the presence of both NH₄NO₃ and KNO₃ as nitrogen sources was required. The use of a single nitrogen source caused a long lag period or inhibition of the cell growth. KH₂PO₄ stimulated the growth when in was used in the level of 2.5 to 5 mM. The cell adhesion on the surface of the fermentor sometimes causes trouble in a large-scale cultivation. It was found that reducing the Ca²⁺ level in the medium prevented the cell adhesion and foaming remarkably. Based on the results obtained, a modified medium was established which was excellent for shortening the culture period and for efficient production of the anti-plant virus inhibitor.     

广州地区中华按蚊生理年龄的组成

中华按蚊是我国平原地区的传疟媒介,研究中华按蚊的生态学,对于疟疾的流行病学及预防均具有重要的意义。生理年龄及生殖营养环的研究,不但可以进一步认识中华按蚊在自然界的一些生态学问题,更重要的是有助于分析其传疟的作用,作为防制的依据。     

Isoenzyme-directed selection and characterization of anti-creatine kinase single chain Fv antibodies from a human phage display library

Epitopes differing among isoenzymes of creatine kinase (CK) are apparently limited in number and poorly immunogenic in vivo. Especially for the BB-CK isoenzyme, very few monoclonal antibodies (mAb) are available. Here, we use in vitro selection with a synthetic human phage display antibody library and develop isoenzyme competition and peptide panning strategies to obtain human single chain Fv (scFv) antibodies against specific CK isoenzymes. We isolated and characterized seven scFv clones that recognize native as well as denatured cytosolic BB-CK in ELISA, immunoblot, immunofluorescence histochemistry and surface plasmon resonance (SPR) spectroscopy. To a variable but minor degree, they also react with cytosolic MM-CK, but not with mitochondrial CK isoenzymes. Epitope mapping revealed that the scFv antibodies recognize different BB-CK epitopes, including the N-terminus and the isoenzyme-specific box, a highly conserved sequence of unknown function for which no mAb were available so far. With a K(D) of 3.5-9.6 x 10(-7) M, the isolated scFv compare favorably with mouse mAb and may overcome certain of their limitations. Our results demonstrate the advantages of in vitro antibody selection for the generation of isoenzyme-specific antibodies.     

Plant-associated bacteria and their role in the success or failure of metal phytoextraction projects: first observations of a field-related experiment

Phytoextraction has been reported as an economically and ecologically sound alternative for the remediation of metal-contaminated soils. Willow is a metal phytoextractor of interest because it allows to combine a gradual contaminant removal with production of biomass that can be valorized in different ways. In this work two willow clones growing on a metal-contaminated site were selected: ‘Belgisch Rood’ (BR) with a moderate metal extraction capacity and ‘Tora’ (TO) with a twice as high metal accumulation. All cultivable bacteria associated with both willow clones were isolated and identified using 16SrDNA ARDRA analysis followed by 16SrDNA sequencing. Further all isolated bacteria were investigated for characteristics that might promote plant growth (production of siderophores, organic acids and indol acetic acid) and for their metal resistance. The genotypic and phenotypic characterization of the isolated bacteria showed that the TO endophytic bacterial population is more diverse and contains a higher percentage of metal-resistant plant growth promoting bacteria than the endophytic population associated with BR. We hypothesize that the difference in the metal accumulation capacity between BR and TO clones might be at least partly related to differences in characteristics of their associated bacterial population.     

Comparing susceptibility of eastern and western US grasslands to competition and allelopathy from spotted knapweed [<Emphasis Type="Italic">Centaurea stoebe</Emphasis> L. subsp. <Emphasis Type="Italic">micranthos</Emphasis> (Gugler) Hayek]

Centaurea stoebe L. subsp. micranthos is native to Eurasia and is invasive in the western portion of the US. Negative impacts of C. stoebe micranthos present in the eastern US have not been recorded. In this study, we examine the effects of C. stoebe micranthos on species diversity on an eastern grassy bald, compare the competitive abilities of plant species from eastern and western grasslands against C. stoebe micranthos, and assess the production of allelopathic compounds in an eastern population of C. stoebe micranthos. Field observations indicated that increasing C. stoebe micranthos abundance was not associated with decreasing abundance or diversity of species. In a greenhouse experiment, C. stoebe micranthos growing with plant species from an eastern grassland were smaller than C. stoebe micranthos growing with species from western grasslands, suggesting that species from the eastern grassland are more competitive against C. stoebe micranthos. We found no evidence that the eastern population of C. stoebe micranthos has allelopathic effects. While the invasion dynamics may change over time, the possibility that C. stoebe micranthos may never become invasive in the studied grassy bald should be weighed when considering control measures here and throughout the eastern US. This study illustrates that invasion dynamics can vary geographically and that land managers need relevant information to gauge an appropriate and economical response.     

Comparative analysis of overwintering physiology in nine species of semi‐aquatic bugs (Heteroptera: Gerromorpha)

In semi‐aquatic bugs (Heteroptera: Gerromorpha), the strategies of overwintering in a cryothermic state (i.e. at body temperatures below the equilibrium freezing point) remain largely unexplored. The present study provides an analysis of the ecophysiological aspects of overwintering in nine gerromorphan species. All nine species avoid ice formation by means of a more or less extensive supercooling of their body fluids. There is a tight correlation between the supercooling point (SCP) and the lower lethal temperature. Different species use different physiological adjustments to increase the likelihood of survival in a supercooled state. These include stabilization of the supercooled state by active antifreeze factors that cause thermal hysteresis between equilibrium melting and freezing points, the accumulation of low‐molecular weight sugars and polyols with putative cryoprotective functions, or by having a relatively high body fluid osmolality, combined with a low level of hydration. The majority of species under study overwinter only as adults, whereas Velia caprai Tamanini can overwinter either as an adult or in the egg stage. The supercooling capacity of V. caprai adults is insufficient to prevent the risk of lethal freezing. The adults therefore survive only opportunistically in suitable microhabitats, and/or during mild winters. The survival of V. caprai in winter is assured by extensive supercooling and having overwintering eggs that are highly cold tolerant.     

Ecotones in vegetation ecology: methodologies and definitions revisited

In this review paper, we highlight some of the trends and issues that have dominated ecotone research over the decade of 1996–2006. The terms and definitions of ecotone research in vegetation ecology are reviewed. We summarize the most important techniques and highlight the discrepancies between the definitions and their scientific application in vegetation ecology. We see a need for semantic uniformity with regard to the term and the definition of “the ecotone”, as the variable and the non-exclusive use of terms and definitions can be a source of confusion when interpreting and comparing different studies. To avoid further confusion, a unique definition of the term “ecotone” should be agreed upon, based upon a set of general characteristics. We therefore adapted and extended the definition from Holland et al. (Ecotones: the role of landscape boundaries in the management and restoration of changing environments, 1991) to “A multi-dimensional environmentally stochastic interaction zone between ecological systems with characteristics defined in space and time, and by the strength of the interaction”. We also advocate that (1) a shift in focus from one-dimensional to two-dimensional techniques in ecotone characterization is desirable and (2) more research into novel techniques, including multi-dimensional data and time series, is needed in view of local and global ecotone changes.