不同分期慢性肾脏病患者血清Klotho蛋白、FGF-23、RBP4、TWEAK水平与肾功能的相关性研究

摘要 目的：探究不同分期慢性肾脏病(CKD)患者血清Klotho蛋白、成纤维细胞生长因子-23(FGF-23)、视黄醇结合蛋白4(RBP4)、肿瘤坏死因子样弱凋亡诱导因子(TWEAK)水平与肾功能的相关性。方法：选择2018年2月至2020年2月我院诊治的80例CKD患者作为CKD组,选择同期在我院进行健康体检的80名健康者作为对照组。检测并比较对照组和CKD组以及不同CKD分期患者血清Klotho蛋白、FGF-23、RBP4、TWEAK水平及肾功能指标水平,采用Pearson相关性分析对血清Klotho蛋白、FGF-23、RBP4、TWEAK水平与肾功能指标的相关性进行分析。结果：与对照组相比,CKD组血清Klotho蛋白、TWEAK水平和肾小球滤过率（GFR）明显下降,而血清FGF-23、RBP4水平、血清肌酐、24尿蛋白定量和血清尿素氮水平明显升高（P<0.05）。Ⅰ～Ⅱ期患者的血清Klotho蛋白、TWEAK水平和GFR最高,其次为Ⅲ～Ⅳ期患者,Ⅴ期患者最低（P<0.05）。而Ⅰ～Ⅱ期患者血清FGF-23、RBP4水平、血清肌酐、24尿蛋白定量和血清尿素氮水平最低,其次为Ⅲ～Ⅳ期患者,Ⅴ期患者最高（P<0.05）。Klotho蛋白和TWEAK水平与血清肌酐、24尿蛋白定量和血清尿素氮水平呈负相关,与GFR呈正相关（P<0.05）。FGF-23和RBP4水平与血清肌酐、24尿蛋白定量和血清尿素氮水平呈正相关,与GFR呈负相关（P<0.05）。结论：CKD患者中血清Klotho蛋白、TWEAK水平以及肾功能下降,FGF-23、RBP4水平明显升高,且血清Klotho蛋白、TWEAK、FGF-23、RBP4水平与肾功能及CKD分期相关。     

Parasite spread in experimental metapopulations: resistance,tolerance and host competence

Host competence, defined as the likelihood that a host will transmit infection, may be affected by an individual's resistance to infection and its ability to withstand damage caused by infection (tolerance). Host competence may therefore be one of the most important factors to impact host–parasite dynamics, yet the relationships among resistance, tolerance and competence are poorly understood. The objective of the present study was to determine whether individual host resistance (ability to resist or minimize infection) and/or tolerance (ability to withstand or minimize reduction in fitness due to infection) contributed to the competence (ability to spread infection) of hosts using guppies infected with the ectoparasite, Gyrodactylus turnbulli. This individual-fish level analysis used data collected from a previous metapopulation experiment that had tracked host–parasite dynamics at the metapopulation scale using individually marked guppies that were moved among experimental tanks within replicate metapopulations. Fish tolerance was measured as the residual from a fish's expected survival post-infection for a given parasite burden. Fish resistance was measured as the peak parasite load (– log-transformed). Host competence was measured as the incidence (number of new infections over two days after the arrival of a fish to a tank) weighted by the density of available uninfected fish in the tank. In contrast to the assumption of a trade-off between resistance and tolerance, individual fish tolerance and resistance were both negatively associated with competence. Connectivity (the number of fish with which an individual came into contact) was not associated with competence. Our results indicate that resistance and tolerance are both important to disease spread. These findings highlight the importance of understanding how individual defence against parasites may contribute to its competence as a host, and therefore impact metapopulation-level dynamics.     

Elevational gradients in constitutive and induced oak defences based on individual traits and their correlated expression patterns

Elevational gradients are useful ecological settings for revealing the biotic and abiotic drivers of plant trait variation and plant–insect interactions. However, most work focusing on plant defences has looked at individual traits and few studies have assessed multiple traits simultaneously, their correlated expression patterns, and abiotic factors associated with such patterns across elevations. To address this knowledge gap, we studied elevational variation in direct (phenolic compounds) and indirect (volatile organic compounds) constitutive defences and their inducibility after feeding by a specialist beetle Altica quercetorum in saplings of 18 wild populations of Quercus pyrenaica. We tested for: 1) clines in each defensive trait individually, 2) their patterns of correlated expression and 3) associations between any such clines and climatic factors. We found that constitutive direct defences (lignins and hydrolysable tannins) decreased with increasing elevation. We observed no elevational gradient for constitutive indirect defences (volatile organic compounds) or the inducibility of direct or indirect defensive traits when looking at groups of compounds. However, at individual tree-level, increased induction of two monoterpenes (α-fenchene and camphene) at higher elevation was shown. Furthermore, we show a significant pattern of co-expression of constitutive and induced phenolics across populations, which weakened with increasing elevation. Finally, we found no evidence that climatic factors were associated with either individual or correlated trait expression patterns across elevations. Overall, these findings call for moving beyond elevational clines in individual plant defences, and argue that assessing elevational shifts in trait correlated expression patterns and their underlying mechanisms can increase our understanding of plant defence evolution and plant–herbivore interactions along environmental gradients.     

Pollen feeding,resource allocation and the evolution of chemical defence in passion vine butterflies

Evolution of pollen feeding in Heliconius has allowed exploitation of rich amino acid sources and dramatically reorganized life‐history traits. In Heliconius, eggs are produced mainly from adult‐acquired resources, leaving somatic development and maintenance to larva effort. This innovation may also have spurred evolution of chemical defence via amino acid‐derived cyanogenic glycosides. In contrast, nonpollen‐feeding heliconiines must rely almost exclusively on larval‐acquired resources for both reproduction and defence. We tested whether adult amino acid intake has an immediate influence on cyanogenesis in Heliconius. Because Heliconius are more distasteful to bird predators than close relatives that do not utilize pollen, we also compared cyanogenesis due to larval input across Heliconius species and nonpollen‐feeding relatives. Except for one species, we found that varying the amino acid diet of an adult Heliconius has negligible effect on its cyanide concentration. Adults denied amino acids showed no decrease in cyanide and no adults showed cyanide increase when fed amino acids. Yet, pollen‐feeding butterflies were capable of producing more defence than nonpollen‐feeding relatives and differences were detectable in freshly emerged adults, before input of adult resources. Our data points to a larger role of larval input in adult chemical defence. This coupled with the compartmentalization of adult nutrition to reproduction and longevity suggests that one evolutionary consequence of pollen feeding, shifting the burden of reproduction to adults, is to allow the evolution of greater allocation of host plant amino acids to defensive compounds by larvae.     

Modification of plant Rac/Rop GTPase signalling using bacterial toxin transgenes

Bacterial protein toxins which modify Rho GTPase are useful for the analysis of Rho signalling in animal cells, but these toxins cannot be taken up by plant cells. We demonstrate in vitro deamidation of Arabidopsis Rop4 by Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1) and glucosylation by Clostridium difficile toxin B. Expression of the catalytic domain of CNF1 caused modification and activation of co‐expressed Arabidopsis Rop4 GTPase in tobacco leaves, resulting in hypersensitive‐like cell death. By contrast, the catalytic domain of toxin B modified and inactivated co‐expressed constitutively active Rop4, blocking the hypersensitive response caused by over‐expression of active Rops. In transgenic Arabidopsis, both CNF1 and toxin B inhibited Rop‐dependent polar morphogenesis of leaf epidermal cells. Toxin B expression also inhibited Rop‐dependent morphogenesis of root hairs and trichome branching, and resulted in root meristem enlargement and dwarf growth. Our results show that CNF1 and toxin B transgenes are effective tools in Rop GTPase signalling studies.     

Plant volatiles induced by herbivore eggs prime defences and mediate shifts in the reproductive strategy of receiving plants

Plants can detect cues associated with the risk of future herbivory and modify defence phenotypes accordingly; however, our current understanding is limited both with respect to the range of early warning cues to which plants respond and the nature of the responses. Here we report that exposure to volatile emissions from plant tissues infested with herbivore eggs promotes stronger defence responses to subsequent herbivory in two Brassica species. Furthermore, exposure to these volatile cues elicited an apparent shift from growth to reproduction in Brassica nigra, with exposed plants exhibiting increased flower and seed production, but reduced leaf production, relative to unexposed controls. Our results thus document plant defence priming in response to a novel environmental cue, oviposition‐induced plant volatiles, while also showing that plant responses to early warning cues can include changes in both defence and life‐history traits.     

重建沿海韧性——旧金山湾盐沼修复及其启示

潮洪灾害、海平面上升已促使沿海城市由“抵御”向“适应”转变。通过修复盐沼提高海岸防护的韧性,已被认可是一种有效的适应对策。选取旧金山湾为案例,基于文献和实地调研,探究城市盐沼修复的实践路径和设计方法。研究表明,适应性管理是旧金山湾三代修复实践得以不断优化、发展的关键,帮助制定、调整目标和方法,弹性应对不确定性;旧金山湾通过发展修复设计导则,加速盐沼修复,促进形成更自然的盐沼;并修复过渡区,提供盐沼向内陆迁移的空间,缓解海岸挤迫。最后,提出中国河口海岸城市实施盐沼修复的可借鉴之处,推进海岸防护措施向基于自然的途径转变。     

Lumbering the gauntlet: Cape Gannet fledglings killed by African Penguins

This account presents the first known observations of Cape Gannet Morus capensis fledgling mortalities as a result of aggressive nest defence behaviour by African Penguins Spheniscus demersus. Observations were conducted in 2013 on Bird Island, Algoa Bay, South Africa – the world's largest breeding colony of Cape Gannets. Twentyeight attacks were witnessed between 21 March and 18 May 2013 of which 16 resulted in mortality. The absence of previous observations of this phenomenon may be due to an unusually high proportion of African Penguin chicks being present relatively early on in the breeding season, associated with a potential for increased nest defence at this stage, and a larger number of gannet fledglings that year compared to previous years over the same period.     

Divergent low water potential response in Arabidopsis thaliana accessions Landsberg erecta and Shahdara

The Arabidopsis thaliana accession Shahdara (Sha) differs from Landsberg erecta (Ler) and other accessions in its responses to drought and low water potential including lower levels of proline accumulation. However, Sha maintained greater seedling root elongation at low water potential and a higher NADP/NADPH ratio than Ler. Profiling of major amino acids and organic acids found that Sha had reduced levels of all glutamate family amino acids metabolically related to proline, but increased levels of aspartate‐derived amino acids (particularly isoleucine), leucine and valine at low water potential. Although Sha is known for its different abiotic stress response, RNA sequencing and co‐expression clustering found that Sha differed most from Ler in defence/immune response and reactive oxygen‐related gene expression. HVA22B and Osmotin34 were two of the relatively few abiotic stress‐associated genes differentially expressed between Ler and Sha. Insensitivity to exogenous glutamine and a different expression profile of glutamate receptors were further factors that may underlie the differing metabolism and low water potential phenotypes of Sha. These data define the unique environmental adaptation and differing metabolism of Sha including differences in defence gene expression, and will facilitate further analysis of Sha natural variation to understand metabolic regulation and abiotic/biotic stress interaction.