Monitoring the persistence of Laccaria bicolor as an ectomycorrhizal symbiont of nursery-grown Douglas fir by PCR of the rDNA intergenic spacer

The large-scale inoculation of selected beneficial ectomycorrhizal fungi in forest nurseries has generated renewed interest in the ecology of these symbiotic fungi. However, information on the dissemination and persistence of introduced symbionts is scarce due to the limitation of the current identification methods. To identify ectomycorrhizal fungi on single root tips, we investigated the polymorphism of the PCR-amplified ribosomal DNA intergenic spacer (IGS) from a wide range of ectomycorrhizal fungi. To investigate the reliability of this molecular approach in large-scale surveys, the dissemination and persistence on Douglas fir seedlings of the introduced Laccaria bicolor S238N were assessed in a forest nursery in the Massif Central (France). Several hundred ectomycorrhizas and fruiting bodies were sampled from plots where control and L. bicolor inoculated-Douglas fir seedlings were grown for 1.5 years. PCR typing of mycorrhizas indicated that trees inoculated with L. bicolor S238N remained exclusively colonized by that isolate (or sexually derived isolates) for the entire test period. In contrast, control seedlings were infected by indigenous isolates of Laccaria laccata and Thelephora terrestris. The molecular evidence for the persistence of the introduced mycobiont despite the competition from indigenous isolates of the same species provides further illustration of the potential of exotic species for large-scale microbial application.     

A chamber for the simulation of radiation freezing of plants

Frost injury to plants can occur following episodic radiation frosts. In the UK this is particularly important to spring sown crops such as potatoes. Most laboratory based frost studies simulate freezing using either conductive or convective freezing chambers. Such frost tests do not simulate overnight freezing events adequately. A freezing chamber based on radiative cooling is described which mimics overnight radiative freezing. The chamber is rectangular in design (1 m × lm × 2 m high) with a radiative cooling plate at the top of the chamber cooled to -40°C to -45°C using HFC coolants, which acts as a cold black body. The sides of the chamber are also cooled to variable temperatures down to -5°C in order to prevent the chamber walls radiating to the plant material during testing. Using thermocouples to measure air temperature and plant temperature the chamber has been characterised to simulate the radiative cooling conditions found in the UK during autumn and spring. Exotherm detection upon plant freezing is simplified by virtue of the reduction in temperature fluctuation normally experienced at the plant surface during natural freezing. Radiation frosts and subsequent frost damage to potatoes have been recorded in the temperature range -4°C to –5°C. The equipment is recommended for studies of frost damage to plants normally caused by episodic radiation frost events.     

乳酸菌黏附小鼠派伊尔结及影响因子的研究

目的研究乳酸菌结合小鼠派伊尔结（PP）的性质,确定乳酸菌黏附小鼠PP的影响因子。方法测定10株荧光标记的乳酸菌对PP组织切片黏附性,分析细菌表面疏水性和酵母、红细胞凝集性与黏附性的关系。结果凝集酵母、红细胞能力强的乳酸菌,PP黏附性强。除嗜酸乳杆菌（L.acidophilm）外,其他9株乳酸菌的表面疏水性与凝集酵母、红细胞的能力呈显著的负相关性（r=-0．60和r=-0．53,P〈0．05）。L.acidophilm黏附PP的能力最强。L．acidophilm黏附PP能力和红细胞凝集性均可被D（＋）-甘露糖、D（＋）-半乳糖抑制。结论乳酸菌黏附PP的能力受疏水性和表面特异性凝集素的影响。L.acidophilm表面D（＋）-甘露糖、D（＋）-半乳糖特异性凝集素可能参与黏附PP的过程。     

Are generalist Aphidiinae (Hym. Braconidae) mostly cryptic species complexes?

Aphidiinae are mostly composed of specialist parasitoids and the few species described as generalist are suspected to be composed of cryptic specialists, almost indistinguishable based on morphological characteristics. The use of molecular markers has proven to be a useful tool for revealing cryptic species complexes and here we use seven mitochondrial and nuclear gene fragments to study possible genetic differentiation among seven Aphidiinae generalists. Maximum likelihood (ML) trees and Bayesian Poisson tree processes (bPTP) models were conducted on each gene separately and on the seven genes together. The standard cytochrome c oxidase I barcode region appeared to be the most polymorphic and probably the best marker to reveal putative cryptic species. However, we showed with ML trees and bPTP models that a complementary use of mitochondrial and nuclear genes was the most relevant approach to reliably identify cryptic genetic clades in the Aphidiinae. Overall, most of the analysed generalist morphospecies were shown to be composed of subgroups related to the aphid host, some of them revealed as cryptic species by the species delimitation analysis. Further studies are needed to reveal the generality of this result in Aphidiinae.     

Hypomania: a transcultural perspective

This study examined the transcultural robustness of a screening instrument for hypomania, the Hypomania Checklist-32, first revised version (HCL-32 R1). It was carried out in 2606 patients from twelve countries in five geographic regions (Northern, Southern and Eastern Europe, South America and East Asia). In addition, GAMIAN Europe contributed data from its members. Exploratory and confirmatory factor analyses were used to examine the transregional stability of the measurement properties of the HCL-32 R1, including the influence of sex and age as covariates. Across cultures, a two-factor structure was confirmed: the first factor (F1) reflected the more positive aspects of hypomania (being more active, elated, self-confident, and cogni-tively enhanced); the second factor (F2) reflected the more negative aspects (being irritable, impulsive, careless, more substance use). The measurement properties of the HCL-32 R1 were largely invariant across cultures. Only few items showed transcultural differences in their relation to hypomania as measured by the test. F2 was higher among men and in more severe manic syndromes; F1 was highest in North and East Europe and lowest in South America. The scores decreased slightly with age. The frequency of the 32 items showed remarkable similarities across geographic areas, with two excep-tions: South Europeans had lower symptom frequencies in general and East Europeans higher rates of substance use. These findings support the interna-tional applicability of the HCL-32 R1 as a screening instrument for hypomania.     

生态学的时空特性(英文)

 众所周知,几乎所有的生态学特征和现象都受限于一定的时间和空间。因此,相应的科学假设和相关的生态学结论也只能基于这些特定的时空尺度范围。我们利用颇为熟知的事例,引用生态学文献中的具体实例,提纲挈领地论述了时空在生态学研究中的重要性。这些实例包括我们在长白山对云、冷杉(Picea jezoensis, Abies nephrolepis)林林冠结构的模拟、在北美应用遥感和气象方法对碳通量的估算,以及测定湿地生态系统对加温的反应等。文中所涉及的所有生态学现象,对时间和空间都有强烈的依赖性。因而, 从生态学问题的提出,到科学假设的演绎,以至试验设计和综合数据分析,都必须以时、空为前提,才不至于导致荒谬结论。     

Accumulation and metabolism of aldicarb by the free-living nematodes Aphelenchus avenae and Panagrellus redivivus

The accumulation and metabolism of aldicarb has been compared in two species of free-living soil nematodes, Aphelenchus avenae and Panagrellus redivivus, which differ considerably in their sensitivity to this and other pesticides. Similar levels of aldicarb were found to accumulate in the two species. The results showed that although the rate of uptake of aldicarb was greater in P. redivivus, so also was the rate of metabolism and elimination. Levels of toxic metabolites of aldicarb were two to three times higher in the more susceptible species A. avenae after 24 h incubation than in the less susceptible P. redivivus. The toxicological significance of these findings is discussed in relation to previous work with the organophosphorus pesticide phorate and its effects on the same two nematode species.     

河内蔬菜基地冬季主要蔬菜上昆虫群落组成

应越南国家植物保护研究院的邀请 ,受我国科技部的委派 ,我们于 2 0 0 1年 1 1～ 1 2月赴越进行“小菜蛾化学信息素的分离鉴定及应用研究”。河内地处热带 ,光照充足 ,雨量充沛 ,气候湿润 ,郊区拥有数百平方公里的蔬菜基地 ,种植着各式各样的蔬菜 ,长势旺盛 ,所产各类蔬菜主要用于出口 ,但虫害较重。在进行小菜蛾PlutellaxylostellaL .化学信息素研究[1] 的同时 ,我们对主要蔬菜品种上的昆虫群落的组成及优势种昆虫进行了考查和分析。1　材料与方法选取 1 0多种蔬菜作为调查对象 ,每种蔬菜样地面积≥ 6 6 6× 2m2 ,以五点取样法选取 5个样…