QuEChERS-超高效液相色谱-串联质谱法测定动物源性食品中30种抗寄生虫类药物残留

目的:采用超高效液相色谱-串联质谱法,建立测定动物源性食品中30种抗寄生虫类药物残留的方法。方法:样品经乙腈、1%氨水乙酸乙酯提取,经QuEChERS净化。净化后采用Waters ACQUITY UPLC^(TM) BEH C_(18)色谱柱分离,10 mmol/L甲酸铵(含0.1%甲酸)水溶液-乙腈:甲醇(50:50,v:v)为流动相进行梯度洗脱,电喷雾离子源正负离子切换多反应监测(Multiple Reaction Monitoring,MRM)模式下进行检测,基质匹配外标法定量。结果:在优化的条件下,30种抗寄生虫类药物在各自的线性范围内线性良好,决定系数(r^(2))均大于0.99;回收率为70.1%~111%;相对标准偏差在0.10%~9.1%之间(n=6);方法检出限为0.001~0.3μg/kg之间,方法定量限在0.004~1μg/kg。结论:该方法灵敏、准确,具有良好的重复性和稳定性,可用于动物源性食品中多种抗寄生虫药物残留的检测。

植物生殖物候研究进展

概述了植物生殖物候的近期研究趋势、研究内容和研究进展。近十几年,生殖物候研究体现了从物种尺度到群落尺度、由野外观察到模拟实验、从孤立研究到关联研究过渡的趋势。主要研究内容包括:(1)特定植物的生殖物候;(2)群落尺度的生殖物候;(3)生殖物候与系统发生的关系;(4)生殖物候的可塑性;(5)生殖物候对气候变化的响应;(6)生殖物候与动物食源供应的关系;(7)生殖物候与花粉过敏症的关系;(8)生殖物候与植物保护和植被管理的关系。控制实验和长期观测将在未来研究中占有重要地位,以植物多样性保护和退化生态系统恢复为目的的研究将趋于增多,有关温带植物和草本植物以及特殊生态系统的研究将得到进一步加强,群落尺度的研究将继续增多。

Terrestrial behavior and use of forest strata in a group of black-and-white snub-nosed monkeys Rhinopithecus bieti at Xiaochangdu,Tibet

Food distribution and predation pressure are considered to be the main ecological factors that influence the use of forest strata （basically arboreality vs. terrestriality） in non-human primates. Here, we investigate ground use of wild, unprovisioned black-and-white snub-nosed monkeys Rhinopithecus bieti by means of the scan sampling method. The results show that the monkeys spent 15.0% of the day time on the ground; 16.6%, 12.7%, and 15.6% for adult males, adult females and juveniles, respectively. Adult males and juveniles of both sexes showed significantly higher rates of terrestrial time than adult females. Females without clinging infants spent significantly more time on the ground than expected, while females with clinging infants spent significantly less time on the ground than expected. These results suggest that the higher degree of terrestrial behavior for males and juveniles may be due to their higher agility in comparison with females. Our study showed that the monkeys fed more on lichens relative to other food items when in the trees, but more on buds/leaves, flowers, fruits/nuts, resin/bark, and herbs when on the ground. According to our investigation, the ecological significance of the species＇ terrestriality lies mainly in the utilization of terrestrial food resources [ Current Zoology 55 （3） ： 180 - 187, 2009].

Risk assessment of dietary exposure to PCDD/Fs, DL-PCBs and NDL-PCBs of Hong Kong resident

Concentrations of PCDD/Fs, dioxin-like PCBs as well as six indicator PCBs were determined in animal origin foods collected from Hong Kong retail market during 2008-2010. The dietary intake of an average Hong Kong adult resident was estimated to be 0.806-0.833 pg WHO-TEQ kg^-1 b.w. d^-1 of dioxin-like compounds, lower than the tolerable daily intake introduced by WHO. The 95th percentile consumer were exposed by dietary at the level of 2.72 to 2.81 pg WHO-TEQ kg^-1 b.w. d^-1 or 81.6-84.3 pg WHO-TEQ kg^-1 b.w. month^-1 , higher than 70 pg WHO-TEQ kg t b.w. month^-1. DL-PCBs contributed 49.2% of total TEQ intake. The daily intake of indicator PCB was 2.83 ng kg^-1 b.w. d^-1. Approximately 2/3 of dietary intake of dioxin-like compounds came from sea food products. Ten brands of infant formula products were tested and the potential dietary intake of formula-fed infants of Hong Kong was estimated to be 1.46-1.58 pg WHO-TEQ kg^-1 b.w. d^-1 during 1st month and decreases afterwards.

Cane toads beneath bird rookeries： utilization of a natural disturbance by an invasive species

Many invasive species exploit anthropogenically disturbed habitats, but most of those taxa evolved long before humans. Presumably, then, an ability to use natural （non-anthropogenic） disturbances pre-adapted invaders to a world later degraded by people. Studies on invasive species in naturally disturbed habitats thus can clarify the ancestral niche of invaders. In the Australian tropics, metallic starlings Aplonis metallica nest communally in emergent rainforest trees during the wet-season, and invasive cane toads Rhinella marina join other predators （mammals, birds, reptiles, and other anurans） to exploit the food resources beneath those trees. Compared to conspecifics found along nearby roads through the forest, cane toads beneath bird-nesting trees occur at higher densities, and are smaller in body size. The sex ratio is female-biased, and recapture records suggest that fe- males may be philopatric at these sites （whereas recaptures were rare for both sexes found along the roads）. Some toads were found under the same trees in successive wet-seasons. Spooling showed that distances moved per night were similar along the road versus under the trees, but toads under trees showed lower net displacements. Diets also differed （based upon scat analysis）, with tree toads feeding more on beetles and less on ants. These nutrient-rich hotspots are ex- ploited primarily by adult females and juvenile toads, whereas adult males congregate at breeding sites. By magnifying pre-existing intraspecific divergences in habitat use, bird rookeries may en- hance population viability of cane toads by enabling critical age and sex classes to exploit food- rich patches that are rarely used by adult males.

From foraging to autonoetic consciousness： The primal self as a consequence of embodied prospective foraging

The capacity to adapt to resource distributions by modulating the frequency of exploratory and exploitative behaviors is common across metazoans and is arguably a principal selective force in the evolution of cognition. Here we （I） review recent work investigating behavioral and biological commonalities between external foraging in space and internal foraging over envi- ronments specified by cognitive representations, and （2） explore the implications of these commonalities for understanding the origins of the self. Behavioural commonalities include the capacity for what is known as area-restricted search in the ecological literature： this is search focussed around locations where resources have been found in the past, but moving away from locations where few resources arc found, and capable of producing movement pattems mimicking L6vy flights. Area-restricted search shares a neural basis across metazoans, and these biological commonalities in vertebrates suggest an evolutionary homology be- tween external and internal foraging. Internal foraging, and in particular a form we call embodied prospective foraging, makes available additional capacities for prediction based on search through a cognitive representation of the external environment, and allows predictions about outcomes of possible future actions. We demonstrate that cognitive systems that use embodied prospec- tive foraging require a primitive sense of self, needed to distinguish actual from simulated action. This relationship has implica- tions for understanding the evolution of autonoetic consciousness and self-awareness.

Identification of neurons responsible for feeding behavior in the Drosophila brain

Drosophila melanogaster feeds mainly on rotten fruits, which contain many kinds of sugar. Thus, the sense of sweet taste has evolved to serve as a dominant regulator and driver of feeding behavior. Although several sugar receptors have been described, it remains poorly understood how the sensory input is transformed into an appetitive behavior. Here, we used a neural silencing approach to screen brain circuits, and identified neurons labeled by three Gal4 lines that modulate Drosophila feeding behavior. These three Gal4 lines labeled neurons mainly in the suboesophageal ganglia （SOG）, which is considered to be the fly＇s pri- mary taste center. When we blocked the activity of these neurons, flies decreased their sugar consumption significantly. In contrast, activation of these neurons resulted in enhanced feeding behavior and increased food consumption not only towards sugar, but to an array of food sources. Moreover, upon neuronal activation, the flies demonstrated feeding behavior even in the absence of food, which suggests that neuronal activation can replace food as a stimulus for feeding behavior. These findings indicate that these Gal4-1abeled neurons, which function downstream of sensory neurons and regulate feeding behavior to- wards different food sources is necessary in Drosophila feeding control.

Traveling wave solutions for a diffusive three-species intraguild predation model

The aim of this work is to investigate the existence and non-existence of traveling wave solutions for a diffusive three-species intraguild predation model which means that one predator can eat its potential resource competitors. The method of upper-lower solution is implemented to show the existence of traveling wave solutions. In order to simplify the construction of an admissible pair of upper lower solution, the scheme of strictly con- tracting rectangle is applied. Finally, the minimal speed c＊ of traveling wave solutions of the model is characterized. If the wave speed is greater than c＊, we show the exis- tence of traveling wave solutions connecting trivial and positive equilibria by combining the upper and lower solutions with the contracting rectangle. On the other hand, if the wave speed is less than c＊, the non-existence of such solutions is also established. Furthermore, to illustrate our theoretical results, some numerical simulations are performed and biological meanings are interpreted.