Determination of simultaneous turnover of serotonin,dopamine and norepinephrine in the telencephalon of unrestrained behaving rats

Rats received an injection of tritiated tryptophan and tyrosine via a chronic indwelling jugular catheter, and at 60 and 90 minutes post-injection, were killed by near-freezing. The three biogenic monoamines were separated by ion exchange and thin layer chromatographyand were quantitated with respect to radioactivity and content. The decline in specific activities can be used to calculate rate constants and turnover of serotonin, dopamine and norepinephrine concurrently in unrestrained behaving animals.     

西北荒漠草原针毛收获蚁的筑巢行为

针毛收获蚁Messoraciculatus(F .Smith)是我国北方特别是西北荒漠草原的优势种蚂蚁 ,亦是重要的种子收获性蚁类 ,收获、贮藏和取食 1 0余种荒漠植物种子。自然巢穴深 80cm～ 1 3 7cm ,单一巢口 ,沿主隧道不同深度有水平延伸的各层巢室 ,巢室向四周的延伸范围随巢深减小 ,层间距拉大。自然巢穴的空间结构与社群越冬与种子的深层贮藏有着密切的关系。饲养社群筑巢行为由蚁后主导 ,起始营巢位点数与蚁后头数有关 ,每一蚁后带领 5 0～ 70头工蚁 ,营巢时程 0 5～ 0 67d 60工蚁 蚁后 ,蚁巢有多个巢口。自然与饲养社群的巢穴结构差异很大 ,但两者单一蚁后与工蚁所占的有效巢穴空间是基本一致的 ,自然社群 1 81 3 7cm3 蚁后 ,2 99cm3 工蚁 ,饲养社群 1 5 6 2 6cm3 蚁后 ,2 60cm3 工蚁     

一株拮抗姜瘟青枯假单胞杆菌的链霉菌的分离及鉴定

从生姜田土中分离到一株对姜瘟青枯假单胞杆菌(PseudomonassolanacarumSmith)有强拮抗作用的链霉菌菌株SR 11,研究拮抗性表明,对革兰氏阳性细菌、革兰氏阴性细菌以及多种病原真菌均有很强的抑制作用。对该菌株进行形态特征、培养特征、生理生化、细胞壁组分分析及16SrDNA序列分析。基内菌丝无横隔、不断裂,气生菌丝多分枝;孢子丝波曲至螺旋形,孢子椭圆形,表面光滑。细胞壁化学组分Ⅰ型,糖型C。在培养成熟后,气丝变为灰色,可闻到浓烈的土味。以16SrDNA序列为基础构建了包括13株相关种属细菌在内的系统发育树,其中,与12个模式链霉菌株的16SrDNA序列的同源性为96 5 %～98 3%。     

The effect of traditional management burning on lichen diversity

Question: How does regular management burning of a northern, Calluna vulgaris‐dominated heathland affect the lichen diversity at the patch and landscape scale? Location: Mar Lodge Estate, Scottish Highlands, United Kingdom. Methods: 26 fire sites of different ages and 11 long‐term unburnt stands were surveyed to create a chronosequence of changing lichen diversity following burning. Data were analysed graphically, with a GLM and using a CCA. Results: Though the immediate effect of fire was to significantly reduce lichen diversity, it generally recovered within 20 years. There was a significant difference in the population dynamics between wet and dry moorland areas with terricolous lichens in the former site being replaced by pleurocarpous mosses. Older stands, unburnt for 25 years or more, generally had lower diversity than stands 10 to 15 years old. Changes in lichen diversity and community composition can be attributed to the development of Calluna stand structure following burning. Conclusions: Fire can be seen to play an important role in maintaining the diversity of lichens in heathland areas by providing a variety of stand‐structures and ages across the landscape that favours the development of greater beta‐diversity.     

不同虫态叉角厉蝽对草地贪夜蛾幼虫的室内捕食作用

为了明确叉角厉蝽 Eocanthecona furcellate (Wolff)对草地贪夜蛾 Spodoptera frugiperda (J.E.Smith)幼虫的控制作用,在实验室条件下测定了叉角厉蝽不同虫态对草地贪夜蛾不同龄期幼虫的捕食能力,研究了该蝽捕食功能反应、搜寻效应以及种内干扰作用。结果表明,叉角厉蝽3龄若虫、5龄若虫、成虫均可捕食草地贪夜蛾幼虫,总体呈现叉角厉蝽低龄若虫捕食草地贪夜蛾低龄幼虫的数量较多,高龄若虫和成虫捕食中间龄期幼虫数量较多的规律;叉角厉蝽3个虫态对草地贪夜蛾2~3龄幼虫的捕食功能反应均符合Holling II方程和HollingⅢ型功能反应新模型;5龄若虫对草地贪夜蛾2~3龄幼虫的捕食效能(a/Th)最强（214.0）、日最大捕食量(1/Th)最大（256.4头）。不同虫态叉角厉蝽的搜寻效应与草地贪夜蛾密度均呈负相关。建立了叉角厉蝽成虫密度、草地贪夜蛾4龄幼虫密度对捕食作用的干扰反应方程,干扰作用发生后该蝽的平均捕食量和捕食作用率均逐渐下降。本研究结果可为田间释放叉角厉蝽防治草地贪夜蛾提供依据。     

Conformation and cooperative order-disorder transition in aqueous solutions of β-1,3-d-glucan with different degree of branching varied by the Smith degradation

β-1,3-d -glucan with different degrees of branching were obtained by selectively and gradually removing side chains from schizophyllan, a water-soluble triple helical polysaccharide, using the Smith degradation. Size exclusion chromatography combined with a multi-angle light scattering detection was performed in aqueous 0.1 M NaCl. The degree of branching decreased after the Smith degradation, while the molar mass distributions were almost unchanged. The molecular conformation of the Smith-degraded β-1,3-d -glucan was analyzed on the basis of the molar mass dependency of the radius gyration, and found to be comparable to the original triple helix of schizophyllan. Differential scanning calorimetry in deuterium oxide–hexadeuterodimethylsulfoxide mixtures was performed to investigate the effects of the degree of branching on the cooperative order-disorder transition. Removal of side chains affects both the transition temperature and transition enthalpy. The ordered structure is formed by the residual side chains in the triplex unit, so that the linear cooperative system of the triplex is maintained after the Smith degradation.     

<Emphasis Type="Italic">Ancient Hunters and Their Modern Representatives</Emphasis>: William Sollas’s (1849–1936) Anthropology from Disappointed Bridge to Trunkless Tree and the Instrumentalisation of Racial Conflict

During the first decades of the 20th century, many anthropologists who had previously adhered to a linear view of human evolution, from an ape via Pithecanthropus erectus(today Homo erectus) and Neanderthal to modern humans, began to change their outlook. A shift towards a branching model of human evolution began to take hold. Among the scientific factors motivating this trend was the insight that mammalian evolution in general was best represented by a branching tree, rather than by a straight line, and that several new fossil hominids were discovered that differed significantly in their morphology but seemed to date from about the same period. The ideological and practical implications of imperialism and WWI have also been identified as formative of the new evolutionary scenarios in which racial conflict played a crucial role. The paper will illustrate this general shift in anthropological theory for one particular scientist, William Sollas (1849–1936). Sollas achieved a synthesis of human morphological and cultural evolution in what I will refer to as an imperialist model. In this theoretical framework, migration, conflict, and replacement became the main mechanisms for progress spurred by ‘ ȁ8nature’s tyrant,’ natural selection.     

Seed-shedding in a Scottish heath community

Abstract. For a 28-week period in late 1987 and early 1988, a study of seed-shedding by several heath species was carried out at the Muir of Dinnet in northeastern Scotland. The dominant species in the heath is Calluna vulgaris. Seed-shedding in Calluna began in early September 1987 and was completed in April 1988, with the period of maximum shedding falling between early November and late December 1987. The total numbers of seeds/m² deposited in stands of Calluna in its four growth-phases were: pioneer, 18 910; building, 169010; mature, 198580; degenerate, 33900. Substantial loss of potential seeds results from the shedding of immature flowers. A control area close to, but outside the area of Calluna dominance had a deposition rate of 770 Calluna seeds/m², indicating sufficient seed to colonise nearby available habitats. Seed rain was also recorded for several other heathland species: Erica cinerea, E. tetralix, Carex spp. and Betula pendula. Seeds of Erica cinerea were deposited in all the Calluna stands, 32670/m² in the pioneer stand, 17600/m² in building, 3720/m² in mature, 210/m² in degenerate (120/m² in the control area). Numbers were greatest at the start of the sampling period, declining thereafter. This applied also to Betula seeds. Erica tetralix occurred in the degenerate Calluna stand and yielded 640 seeds/m² (400/m² in the control area). Seeds of Carex spp. were obtained in the control: 4110/m². The method of sampling has a significant effect on the figures obtained. A method using tube collectors, emptied frequently, is recommended.     

Vegetation development on moorland after control of Pteridium aquilinum with asulam

Abstract. A range of moorland sites in the North York Moors National Park were surveyed where Pteridium aquilinum has been sprayed once with the herbicide asulam between 1 and 7 yr before. The regeneration of both P. aquilinum and the moorland vegetation were studied. The latter was variable and much slower than reported for lowland grassland or heathland, with a large proportion of the developing plant cover consisting of mosses, especially Campylopus introflexus. This slow rate of revegetation was primarily due to the paucity of micro-sites offered for germination in dense P. aquilinum litter, the poor establishment of seedlings in this litter and its slow breakdown. The consequences of this slow and variable development of vegetation to moorland restoration are discussed.     

Nutrient limitation in species-rich lowland fens

Abstract. Nitrogen, phosphorus and potassium were supplied to some Belgian fens of varying nutrient status and productivity. Plant growth in the lowest productive fen with a species-rich Caricion davallianae vegetation was strongly P-limited. N was ineffective when applied alone, but increased the effect of P-addition when applied together. Summer biomass and plant nutrient concentrations were monitored for four years, and showed partial recovery of nutrient limitation. In a more productive fen dominated by Carex lasiocarpa and in a fen meadow, nutrient limitation was less strong. N limited growth in the productive fen, and N and K were co-limiting in the fen meadow. The P-concentration in the productive fen vegetation showed a marked increase after P-fertilization, but it did not result in higher standing crop. The significance of P-limitation for the conservation of species rich low productive fens is discussed. P-limitation may be an essential feature in the conservation of low productive rich fens: because it is less mobile in the landscape than N and/or because it is an intrinsic property of this vegetation type. Plant nutrient concentrations and N:P-ratios may be used as an indication for the presence and type of nutrient limitation in the vegetation. We found N:P-ratios of 23 to 31 for a P-limited site and 8 to 15 in N-limited sites. This was in agreement with critical values from the literature: N:P > ca. 20 for P-limitation and N:P < 14 for N-limitation. Thus, this technique appears valid in the vegetation types that were studied here.