天敌昆虫利用信息化学物质寻找寄主或猎物的研究进展

应用天敌昆虫控制害虫是传统生物防治中的主要内容。信息化学物质是天敌昆虫远距离向寄主或猎物栖息地进行定向,以及近距离对寄主或猎物进行定位所依赖的重要信号。综述了能够引诱天敌昆虫的信息化学物质的产生、分类、作用、异同及背景,并介绍了天敌昆虫对信息化学物质的行为反应和特异性。同时,对这类物质在生物防治中的应用及前景作了介绍与探讨。对不同营养层的种间化学通讯作为研究协同进化时的重要参考也作了简要介绍。     

江西省武功山地区种子植物新资料

报道产自武功山地区的6种新记录种子植物,包括江西省新记录种子植物4种:望春玉兰(Magnolia biondii Pampan.)、桑叶葡萄(Vitis heyneana subsp.ficifolia(Bunge)C.L.Li)、湖南黄芩(Scutellaria hunanensis C.Y.Wu)、疏花车前(Plantago asiatica L.subsp.erosa(Wall.)Z.Y.Li),以及武功山地区新记录种子植物2种:肾萼金腰(Chrysosplenium delavayi Franch.)和佛光草(Salvia substolonifera Stib.),并对每种新记录植物的主要分类特征、价值以及植物地理意义进行了讨论,凭证标本均保存于吉首大学植物标本馆(JIU)和中山大学标本室(SYS)。     

Traits mediate drought effects on wood carbon fluxes

CO₂ fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood how traits and climate interact to influence wood CO₂ fluxes. Here, we examined the responses of CO₂ fluxes from dead wood with different traits (angiosperm and gymnosperm) to 0%, 35%, and 70% rainfall reduction across seasonal temperature gradients. Our results showed that drought significantly decreased wood CO₂ fluxes, but its effects varied with both taxonomical group and drought intensity. Drought‐induced reduction in wood CO₂ fluxes was larger in angiosperms than gymnosperms for the 35% rainfall reduction treatment, but there was no significant difference between these groups for the 70% reduction treatment. This is because wood nitrogen density and carbon quality were significantly higher in angiosperms than gymnosperms, yielding a higher moisture sensitivity of wood decomposition. These findings were demonstrated by a significant positive interaction effect between wood nitrogen and moisture on CO₂ fluxes in a structural equation model. Additionally, we ascertained that a constant temperature sensitivity of CO₂ fluxes was independent of wood traits and consistent with previous estimates for extracellular enzyme kinetics. Our results highlight the key role of wood traits in regulating drought responses of wood carbon fluxes. Given that both climate and forest management might extensively modify taxonomic compositions in the future, it is critical for carbon cycle models to account for such interactions between wood traits and climate in driving dynamics of wood decomposition.     

Placenta Growth Factor in Eyes with Neovascular Glaucoma Is Decreased after Intravitreal Ranibizumab Injection

Purpose

To evaluate changes in the concentrations of placental growth factor (PlGF) and vascular endothelial growth factor-A (VEGF-A) in aqueous humor of patients with neovascular glaucoma (NVG) before and after an intravitreal injection of ranibizumab (IVR) and to determine the underlying correlation between the levels.

Methods

The prospective interventional comparative study involved 20 eyes of 20 patients with surgery-required advanced NVG and 20 control subjects from January 2013 to November 2013. The NVG eyes received the IVR treatment before glaucoma surgery. Aqueous humor was collected at the time of the IVR injection (pre- IVR) and at the time of antiglaucomatous surgery (post-IVR). Aqueous humor was also collected at the time of cataract surgery in normal control. Aqueous humor and plasma VEGF-A and PlGF levels were measured with an enzyme-linked immunosorbent assay methods, respectively.

Results

The mean aqueous humor PlGF and VEGF-A concentrations in the pre-IVR eyes were significantly higher than in those of the control subjects (p<0.001), whereas the plasma levels showed no significant difference. There was a statistically significant correlation between the aqueous humor PlGF and the VEGF-A concentration (r = 0.612, p = 0.003). The mean aqueous humor PlGF in the post-IVR eyes dramatically decreased from 1078.36 ± 755.83 to 177.64 ± 151.73 pg/mL (p<0.001). The VEGF-A level showed a similar trend from 3697.64 ± 2104.47 pg/mL to 183.54 ± 130.35 pg/mL (p<0.001).

Conclusions

Aqueous humor concentrations of VEGF-A and PlGF were significantly elevated in the eyes with NVG, and there was a positive correlation between the levels. After an IVR treatment, VEGF-A and PlGF were significantly decreased in NVG eyes.     

长白山西坡小叶章侵入苔原带过程及影响

长白山西坡岳桦林带的草本植物(以小叶章为代表)侵入了苔原带,形成了独特的植物入侵现象。在光谱及影像分析的基础上,结合GPS(Global Positional System)定位技术,并依据小叶章与牛皮杜鹃的光谱差异及其反演的NDVI(Normalized Difference Vegetation Index)植被指数,揭示小叶章侵入苔原带的过程;通过对不同侵入时间、强度的斑块进行群落调查及土壤测试,探究小叶章侵入苔原带的生态后果。结果显示小叶章侵入苔原带始于20世纪80年代后期,由低海拔向高海拔推进,进入21世纪后逐渐形成了稳定的以小叶章为优势物种的植物群落结构。目前,低海拔处的小叶章斑块经过多年扩张已连接成片,而高海拔处的斑块正处于扩张的初期阶段。从生物多样性变化可以看出,小叶章侵入苔原带导致植物群落多样性升高和物种数量的增加,苔原带原有的灌木数量明显减少,草本植物逐渐增多。植被的改变影响了土壤的理化性质,C/N比下降,土壤腐殖质含量和全氮含量下降,但速效氮和土壤持水能力上升,土壤养分的高效利用又进一步推动了小叶章的侵入。小叶章侵入苔原带已经造成了严重的生态后果。     

黄河调水调沙对黄河口海域双酚A的影响

于2011年6—7月黄河调水调沙前、中期、后对黄河口海域双酚A(BPA)污染情况进行调查,研究了调水调沙对黄河口海域双酚A的影响。结果表明:黄河口13个站位表层海水和沉积物中均有双酚A检出,以调水调沙前测得的海水和沉积物中双酚A含量评估黄河口附近双酚A的污染程度。海水中双酚A浓度范围为13.6—64.0 ng/L,平均浓度为26.2 ng/L;沉积物中双酚A的浓度为0.559—2.73μg/kg干重,平均浓度为1.19μg/kg,是海水中平均含量的48倍。黄河河口区域海水中双酚A浓度受调水调沙影响而呈现较大变化,调水调沙后双酚A浓度明显增加,调水调沙前、后呈显著性差异(P0.01),说明陆源输入是黄河口区域中双酚A的主要污染来源。离入海口近的站位沉积物中双酚A浓度受调水调沙影响较大,呈显著性差异(P0.01),调水调沙后含量显著降低。黄河口海域已经遭受双酚A污染,存在生态安全问题。     

Increased Notch Signaling Enhances Radioresistance of Malignant Stromal Cells Induced by Glioma Stem/ Progenitor Cells

Background

Host malignant stromal cells induced by glioma stem/progenitor cells were revealed to be more radiation-resistant than the glioma stem/progenitor cells themselves after malignant transformation in nude mice. However, the mechanism underlying this phenomenon remains unclear.

Methods

Malignant stromal cells induced by glioma stem/progenitor cell 2 (GSC-induced host brain tumor cells, ihBTC2) were isolated and identified from the double color-coded orthotopic glioma nude mouse model. The survival fraction at 2 Gy (SF2) was used to evaluate the radiation resistance of ihBTC2, the human glioma stem/progenitor cell line SU3 and its radiation-resistant sub-strain SU3-5R and the rat C6 glioma cell line. The mRNA of Notch 1 and Hes1 from ihBTC2 cells were detected using qPCR before and after 4 Gy radiation. The expression of the Notch 1, pAkt and Bcl-2 proteins were investigated by Western blot. To confirm the role of the Notch pathway in the radiation resistance of ihBTC2, Notch signaling blocker gamma secretase inhibitors (GSIs) were used.

Results

The ihBTC2 cells had malignant phenotypes, such as infinite proliferation, hyperpentaploid karyotype, tumorigenesis in nude mice and expression of protein markers of oligodendroglia cells. The SF2 of ihBTC2 cells was significantly higher than that of any other cell line (P<0.05, n = 3). The expression of Notch 1 and Hes1 mRNAs from ihBTC2 cells was significantly increased after radiation. Moreover, the Notch 1, pAkt and Bcl-2 proteins were significantly increased after radiation (P<0.05, n = 3). Inhibition of Notch signaling markedly enhanced the radiosensitivity of ihBTC2 cells.

Conclusions

In an orthotopic glioma model, the malignant transformation of host stromal cells was induced by glioma stem/progenitor cells. IhBTC2 cells are more radiation-resistant than the glioma stem/progenitor cells, which may be mediated by activation of the Notch signaling pathway.     

Low genetic variation detected within the widespread mangrove species Nypa fruticans (Palmae) from Southeast Asia

Genetic diversity within and among six natural populations of Nypa fruticans from China, Vietnam, and Thailand was assessed using SSR and ISSR analysis. Our results showed an extremely low level of genetic diversity of N. fruticans (at the species level, P = 11.76% and 2.88%, He = 0.0279 and 0.0113, I = 0.0470 and 0.0167 by SSRs and ISSRs, respectively) across a total of 183 individuals. No genetic variation was detected within any population except for the Thailand population by SSRs (P = 11.76%, He = 0.0417; I = 0.0622). The bottlenecks during glacial epochs, founder effects, and propagation pattern may be responsible for the extremely low level of genetic diversity of N. fruticans.