Multiple common garden experiments suggest lack of local adaptation in an invasive ornamental plant

Aims Adaptive evolution along geographic gradients of climatic conditions is suggested to facilitate the spread of invasive plant species, leading to clinal variation among populations in the introduced range. We investigated whether adaptation to climate is also involved in the invasive spread of an ornamental shrub, Buddleja davidii, across western and central Europe.Methods We combined a common garden experiment, replicated in three climatically different central European regions, with reciprocal transplantation to quantify genetic differentiation in growth and reproductive traits of 20 invasive B. davidii populations. Additionally, we compared compensatory regrowth among populations after clipping of stems to simulate mechanical damage.Important findings Our results do not provide evidence for clinal variation among invasive B. davidii populations: populations responded similarly to the different environments, and trait values were not correlated to climatic conditions or geographic coordinates of their home sites. Moreover, we did not detect differences in the compensatory ability of populations. We suppose that the invasive spread of B. davidii has been facilitated by phenotypic plasticity rather than by adaptation to climate and that continent-wide shuffling of cultivars due to horticultural trade may have limited local adaptation so far.     

Meteorological conditions are associated with physical activities performed in open-air settings

Meteorological conditions (MC) are believed to modify physical activity. However, studies in this area are limited and none have looked at the associations between MC and physical activity in open-air settings. Therefore, we examined the relationships between MC and physical activities performed on sidewalks/streets and outdoor oval tracks. Observation techniques were used to count individuals walking to school, exercising on oval tracks and walking/jogging/biking on sidewalks/streets. Meteorological conditions were obtained from an Automated Surface Observing System located at a nearby airport for the same time periods physical activities were observed. On weekdays, fewer children were seen walking to school and more bicyclists were observed on sidewalks/streets as wind speed increased (p < 0.05). Ambient and apparent temperatures were positively (p < 0.05) and humidity and barometric pressure negatively (p < 0.005) related to the number of individuals walking on the track. Meteorological conditions were not significantly associated with physical activities observed on weekends. Multiple linear regression analyses showed that apparent temperature (+), barometric pressure (−) and dew point (−) accounted for 58.0% of the variance in the number of walkers on the track. A significant proportion of the variance (>30%) in the number of joggers and the length of time they jogged was accounted for by apparent temperature (+) and dew point (−). We found that meteorological conditions are related to physical activity in open-air settings. The results embellish the context in which environmental–physical activity relationships should be interpreted and provide important information for researchers applying the observation method in open-air settings.     

Studying non-covalent enzyme carbohydrate interactions by STD NMR

Saturation transfer difference NMR spectroscopy is used to study non-covalent interactions between four different glycostructure transforming enzymes and selected substrates and products. Resulting binding patterns represent a molecular basis of specific binding between ligands and biocatalysts. Substrate and product binding to Aspergillus fumigatus glycosidase and to Candida tenuis xylose reductase are determined under binding-only conditions. Measurement of STD effects in substrates and products over the course of enzymatic conversion provides additional information about ligand binding during reaction. Influences of co-substrates and co-enzymes in substrate binding are determined for Schizophyllum commune trehalose phosphorylase and C. tenuis xylose reductase, respectively. Differences between ligand binding to wild type enzyme and a corresponding mutant enzyme are shown for Corynebacterium callunae starch phosphorylase and its His-334-->Gly mutant. The resulting binding patterns are discussed with respect to the possibility that ligands do not only bind in the productive mode.     

Corticosterone metabolites in blue tit and pied flycatcher droppings: effects of brood size, ectoparasites and temperature

The hypothalamic-pituitary-adrenal (HPA) axis of birds induces the secretion of corticosterone (CORT) as a response to different ecological variables. In this study we tested experimentally if manipulations of brood size or ectoparasitism led to subsequent differences in the concentration of excreted CORT metabolites of adult and nestling blue tits (Cyanistes caeruleus). No significant effect of the manipulation of brood size was detected in adults or nestlings. No significant effect of ectoparasitism was detected in males or nestlings, although females from uninfested nests showed lower concentrations of excreted CORT metabolites. In addition, we analysed if weather conditions had an influence on the concentration of excreted CORT metabolites of blue tits and pied flycatchers (Ficedula hypoleuca) breeding in the same forest. We detected no effect of weather conditions on adults, but nestlings of both species showed a negative correlation between their excreted CORT metabolites and the average mean temperatures they were subjected to during their growth. This effect was not found in blue tits in a colder year, suggesting that the sensitivity of the HPA axis to ambient temperature may be subjected to interannual variation. Moreover, we found a positive effect of the maximum temperature on the day of sampling on the concentration of CORT metabolites of blue tit nestlings in one of the years. These results suggest that weather conditions may act as environmental stressors to which the HPA axis of blue tit and pied flycatcher nestlings may be sensitive.     

Twenty years of hydropower regulation in the River Alta: long-term changes in abundance of juvenile and adult Atlantic salmon

The River Alta, northern Norway (70°N), was regulated for hydropower in 1987. Densities of juveniles and catches of adult Atlantic salmon have been studied since 1980–1981 to examine the effects of regulation. The need to control environmental variables during electrofishing was emphasized, as flow variables explained up to 42% of the variation in estimated juvenile densities. The number of spawning redds was counted along the river from 1996 to 2005. The annual number of spawning redds was correlated with the catch of multi-sea-winter salmon (predominantly females). In the upper 7 km section, just downstream of the power station outlet, juvenile densities were reduced by 80% from pre-regulation levels to minimum levels in 1992–1996. This was followed by partial recovery during 1997–2005, although not entirely back to pre-regulation levels. In contrast, the general trend in the middle part of the river was a linear increase in juvenile densities during 1981–2005. Decreased juvenile densities in the upper section was subsequently followed by reduced catches of adult salmon in this part of the river. The relative catches of smolt year classes migrating to sea in the upper section was reduced by up to 75% from 1991 onwards. Spawning and recruitment in the upper section have increased in recent years, probably back to the introduction of catch-and-release angling and an increase in salmon runs. However, present day smolt production in the upper section is still reduced compared to the middle part of the river, 18 years after regulation. The decreased densities of juvenile salmon in the upper section were probably caused by several factors, of which stranding mortality due to sudden drops in the water level and increased winter mortality due to changed environmental conditions, especially reduced ice-cover, may be the most important. In conclusion, the regulation caused a considerable reduction of the salmon production in the upper 16% of salmon reaches, but did not affect the salmon population negatively further downstream. This study illustrates that apparently small environmental disturbances can cause large changes in Atlantic salmon abundance in high latitude populations. Guest editors: R. L. Welcomme & G. Marmulla Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries     

European anchovy (<Emphasis Type="Italic">Engraulis encrasicolus</Emphasis>) landings and environmental conditions on the Catalan Coast (NW Mediterranean) during 2000–2005

Generalized additive models are proposed for a better understanding of the underlying mechanisms for anchovy variations in abundance. Environmental variables derived from satellite imagery (surface chlorophyll, sea surface temperature and wind-mixing index), river discharge (Rhône River and Ebre River) and anchovy landings (landings per unit of effort) as proxy for abundance were used, and three fishing zones were defined along the Catalan Coast. A time shift among wind index mixing, sea surface temperature and chlorophyll was observed for these variables to be significantly correlated with anchovy. Results pointed out to processes that appear to greatly influence species abundance and affect different life stages of anchovy (conditions preceding reproduction, larvae growth and survival and recruits growth). A high proportion of anchovy LPUE variability could be explained by environmental variables. Thus, some univariate models explained deviance are more than 50%, even up to around 70% of anchovy variability. In several cases the deviance explained by a given variable was even higher at the longer time-lags. Among all univariate and bivariate models fitted, the model that best explained anchovy LPUE variability, 79% of total deviance, was a model proposed for the central zone, based on the additive effect of surface chlorophyll and Rhône River discharge, considering time lags of 15 and 18 months, respectively, for each variable.     

微生物絮凝剂的菌种培养及絮凝活性研究

从活性污泥中分离出具有絮凝活性的菌种作为微生物絮凝剂,通过将其对高岭土悬浊液进行絮凝活性测定,得出了适于该菌产絮凝剂的最佳培养基为：以浓度为1．5％的葡萄糖作为碳源,以NH4Q0．06％ 酵母膏0．04％相组合为氮源,以浓度0．3％的KH2PO4作为无机营养物质,其它培养条件pH值为7～8,温度为30℃,摇床转速为180r／min。并将培养好的菌液用于多种废水净化,试验结果表明：其絮凝率与去除率均达90％以上,具有较好的净化效果。     

Colony productivity and foundress behaviour of a native wasp versus an invasive social wasp

Abstract.  1. Colony productivity, prey utilisation, and foundress behaviour of a North American native wasp ( Polistes fuscatus ) versus an European invasive wasp ( Polistes dominulus ) were investigated in a controlled field experiment with optimal versus natural foraging conditions. Colonies with the optimal prey foraging conditions were provided with prey ad libitum within an enclosed area. The other colonies foraged in the adjacent field–woodland but had the same nest conditions as the other treatment.
2. When given prey ad libitum , both wasp species captured similar amounts of prey and the conversion to total offspring biomass was similar. But P. dominulus colonies produced 2.5 times the number of workers as P. fuscatus colonies, reflecting the smaller size of P. dominulus wasps.
3. Foundresses of P. dominulus were observed more often building or repairing the nest, thereby contributing to the production of colonies with twice as many cells as colonies of P. fuscatus . Foundresses of P. dominulus showed more acts of aggression toward workers than did P. fuscatus foundresses, which was not a function of adult density on the nest.
4. At the end of the experiment, P. dominulus colonies with optimal prey foraging conditions still had a high level of egg-laying and peaked in the number of pupae then, whereas egg-laying and the number of pupae per colony of the other treatments began to decline 2–3 weeks earlier. These results indicate that P. dominulus is more opportunistic than P. fuscatus , which may account in part for P. dominulus 's success as an introduced species in North America.     

E.aero高产1.3-丙二醇菌株发酵条件的研究(Ⅱ)

建立了1.3-丙二醇高产菌株(Enterobacter aerogenes简写为E.aero-N-56)1.3-PD厌氧发酵最适pH值、温度、时间、接种量分别为7.0、30℃、48h、9％;在最适发酵条件下,30L发酵罐中E.aero-N-56菌株1.3-PD产量为47.36g/L,生产率为23.68g/L·d。     

小麦全蚀病菌胞外β-1,3-葡聚糖酶的产生和部分特性的研究*

本文就小麦全蚀病菌胞外-1,3-葡聚糖酶的产生和部分酶学特性进行了研究。结果表明,小麦全蚀病菌能够产生胞外-1,3-葡聚糖酶。在供试的三种培养基中,最佳产酶培养基为改进的MS培养基。当以改进的MS为基础培养基时,最佳碳源为麦麸皮;最佳氮源为牛肉浸膏;产酶的最适条件为培养基初始pH为6,培养温度为26℃,250ml三角瓶中装培养基量为50ml时接菌量为4块菌饼(直径5mm)。另外,对酶的部分性质的研究结果表明,酶最适作用温度和pH分别为60℃和7.0,在50℃以下以及pH 5.5～7.5范围内稳定。