Use of RAPD patterns for clone verification and in studying provenance relationships in Norway spruce (Picea abies)

 We have used the RAPD technique to analyse samples of Picea abies obtained from an improvement forestry station. Two types of plant material were harvested, the first being clones and the second provenances from various regions. We first checked the clonal identity of elite tree cuttings and clones; some differences in the RAPD patterns resulting from mis-planting or mis-labelling of cuttings were found. We also established a reference library of RAPD fingerprints for 96 clones, which will serve as a reference source in cases of litigation concerning clone identity. The RAPD technique was also used to study the genetic relationship between nine European provenances of Norway spruce. A dendogram was obtained by individual pairwise comparison of 42 RAPD bands, which separated the nine provenances into two major groups, one containing the Nordic provenances (Sweden and Bielorussia) and another the Alpine provenances (France, Austria, Germany and Belgium). The Belgian provenance, which is not indigenous, is most closely related to the German provenance. We conclude that the RAPD technique is a useful tool for forestry stations in managing propagation operations. Received: 15 June 1996 / Accepted: 11 October 1996     

Potential and attainable food production and food security in different regions

Growing prosperity in the South is accompanied by human diets that will claim more natural resources per capita. This reality, combined with growing populations, may raise the global demand for food crops two- to four-fold within two generations. Considering the large volume of natural resources and potential crop yields, it seems that this demand can be met smoothly. However, this is a fallacy for the following reasons. (i) Geographic regions differ widely in their potential food security: policy choices for agricultural use of natural resources are limited in Asia. For example, to ensure national self-sufficiency and food security, most of the suitable land (China) and nearly all of the surface water (India) are needed. Degradation restricts options further. (ii) The attainable level of agricultural production depends also on socio-economic conditions. Extensive poverty keeps the attainable food production too low to achieve food security, even when the yield gap is wide, as in Africa. (iii) Bio-energy, non-food crops and nature compete with food crops for natural resources. Global and regional food security are attainable, but only with major efforts. Strategies to achieve alternative aims will be discussed. <br>     

Effects of Microbial and Other Antagonistic Organism and Competition on Entomopathogenic Nematodes

Antagonistic factors, broadly identified as antibiosis, competition and natural enemies, impact on entomopathogenic nematodes. Antibiosis can occur through the release of plant chemicals from the roots into the soil, which may adversely affect the host-finding behavior of the infective stage nematode, or the presence of these chemicals in the host insect may negatively affect nematode reproduction. In laboratory studies, intra-specific and inter-specific competition reduces nematode fitness, and inter-specific competition can cause local extinction of a nematode species. For example, after concomitant infection of a host, a steinernematid species usually excludes a heterorhabditid species. The mechanism for the steinernematid superiority has been postulated to be a bacteriocin(s) produced by Xenorhabdus, the symbiotic bacterium of the steinernematid, which prevents Photorhabdus, the symbiotic bacterium of the heterorhabditid, from multiplying. Inter-specific competition between two steinernematid species shows that both can co-exist in a host, but one species will eventually prevail in the environment. By having different foraging strategies, however, both steinermatid species may co-exist in the same habitat. An important issue is whether the introduction of an exotic entomopathogenic nematode species will competitively displace an indigenous nematode species. Although the environmental risks are small, the recommended policy is that the introduction of exotic nematodes be regulated. With other pathogens, entomopathogenic nematodes can out-compete entomopathogenic fungi, but not Bacillus thuringiensis, for the same host individual when both the nematode and entomopathogen are applied simultaneously. The best studied natural enemy is the nematophagous fungus, Hirsutella rhossiliensis, which causes higher mortality in Steinernema glaseri compared with Heterorhabditis bacteriorphora. Differential susceptibility to the fungus may be associated with the retention of the second-stage cuticle by H. bacteriophora. Invertebrate predators including mites and collembolans feed on entomopathogenic nematodes. Although a number of studies have been conducted with antagonists, there is a dearth of field data. We suggest that long-term research plots be established where natural populations of entomopathogenic nematodes occur and include antagonists as a component of such studies.     

浙江安吉龙山林场及其周围地区的鸟类

浙江安吉龙山林场及其周围地区共记录到鸟类１１目２７科９５种,其中留鸟３６种,占鸟类总数的３８％,延徒鸟５９种,占６２％。夏候鸟于春季（４月７日）到达,秋季（１０月２４日）离去,持续停留时间约２０１天。大部分冬候鸟和旅鸟于秋季（９月１２日）出现,春季（５月１６日）离去,持续停留时间约２４７天。柳莺,主要是黄柳莺的情况比较特殊,除６月份外,几乎全年都可看到。人工林内有鸟类８４种,条带统计记录到５９种。     

No Story Is Ever Just a Story

The 41 films at the 2004 Margaret Mead Film and Video Festival showcased a multiplicity of styles and approaches, thus widening the perspective of "what counts" as ethnographic film. The two main events—A Tribute to Jean Rouch and Native Voices—epitomized the festival's commitment to diversity and creative talent. Despite the festival's awkward location in the American Museum of Natural History, the films tackled challenging political subjects and directly addressed questions of representation. Postscreening musical performances, informational panels, and audience–director discussion sessions shaped the festival itself as an ethnographic experience, as well as being a venue for the year's best documentary films. Festival highlights were Raven Tales: How Raven Stole the Sun (2004), Mr. Patterns (2004), and Beauty Academy of Kabul (2004).     

Protein phylogenies provide evidence of a radical discontinuity between arthropod and vertebrate immune systems

 Protein phylogenies were used to test the hypothesis that aspects of the innate immune system of vertebrates have been conserved since the last common ancestor of vertebrates and arthropods. The phylogeny of lysozymes showed evidence of conservation of function, but phylogenies of seven other protein families did not. Natural resistance-associated macrophage protein, nitric oxide synthetase, and serine protease families all showed a pattern of gene duplication within vertebrates after their divergence from arthropods, giving rise to immune system-expressed genes in vertebrates. Insect hemolin, a member of the immunoglobulin superfamily, was found not to be closely related to members of that family having an immune system role in vertebrates; rather, it appeared most closely related to both arthropod and vertebrate molecules expressed in the nervous system. Thus, hemolin seems to have evolved its role independently in insects, probably through duplication of a neuroglian-like ancestor. Furthermore, vertebrate immune system-expressed serpins, chitinases, and pentraxins were found to lack orthologous relationships with arthropod members of the same families also functioning in immunity. Therefore members of these families have evolved immune system functions independently in the two phyla. It is now widely recognized that the specific immune system of vertebrates has no counterpart in invertebrates; these phylogenetic analyses suggest that there is a similar evolutionary discontinuity with respect to innate immunity as well. Received: 10 May 1997 / Revised: 10 September 1997     

Localization of five new Ly49 genes, including three closely related to Ly49c

 Nine genes belonging to the mouse Ly49 multigene family of natural killer cell receptors have been identified to date. Two of these genes, Ly49h and i, are very closely related to the well characterized Ly49c gene in the carbohydrate recognition domain. Here we show by Southern blotting that at least two additional new sequences exist in C57BL/6 mice that are also closely related to Ly49c in the carbohydrate recognition domain. Furthermore, in contrast to Ly49a, extensive variation in the arrangement and number of Ly49c–related genes in different mouse strains was observed. To characterize and localize the new Ly49c–related genes in C57BL/6 mice, we isolated and mapped genomic P1 clones hybridizing to an Ly49C exon 7 probe. Locations and the relative order of all Ly49 genes found within the clones was determined. We also used polymerase chain reaction to sequence exons 2, 4, and 7 from all genes. In this manner, we identified five new potential Ly49 genes which have been tentatively termed Ly49j-n. Ly49j, k, and n belong to the Ly49c–related subfamily, whereas Ly49l and Ly49m are most similar to Ly49d and g, respectively. Interestingly, the members of the Ly49c–related subfamily are not clustered as a unit but are interspersed among other Ly49 genes. These results illustrate the complex nature of the Ly49 gene family and should aid in the understanding of functions, such as the mediation of hybrid resistance, in which Ly49c–related genes play a role. Received: 10 December 1997 · Revised: 28 February 1998     

小黄家蚁工蚁对褐稻虱的捕食作用

报道了小黄家蚁对褐稻虱的捕食作用．养虫笼及大试管捕食试验结果表明,小黄家蚁对褐稻虱若虫尤其是低龄若虫具有良好的捕食效果,捕食率分别为９３％和３０％,捕食的功能反应为ＨｏｌｉｎｇⅡ型反应,水稻品种抗性与捕食反应之间存在协同作用．     

人感染钩体菌群与免疫血清群及交叉凝集关系研究

为了解人间自然感染各群钩端螺旋体（钩体）后产生的免疫抗体血清群、交叉凝集（交凝）、效价及相互关系,作者对病原学阳性并做过双份血清ＭＡＴ的６４份资料作了综合分析,结果表明：６４株钩体属于１２个群,其中１３株菌的感染者血清呈阴性反应,占２０．３１％;５１例呈阳性,占７９．６９％,有１４个血清群,效价１∶１００～１∶６４００;１２个菌群感染者的血清交凝反应较为普遍,效价１∶１００～１∶３２００;效价高低及交凝群数,因感染菌群而异。较为特殊的是１１个菌群感染者的血清中均不见与流感伤寒群钩体的交凝现象。本文对人间分离钩体菌群与免疫血清群构成比例互不吻合的问题作了解释,为钩体病的免疫及血清流行病学补充了新论据     

Detecting clinal and balanced selection using spatial autocorrelation analysis under kin-structured migration

Recently spatial autocorrelation has been employed to infer microevolutionary processes from patterns of genetic variation. In theory, different processes should show characteristic signature correlograms; e. g., clinal selection should produce correlograms decreasing from positive to negative autocorrelation, whereas uniform balanced selection should lead to no spatial autocorrelation. The ability of a statistical method such as spatial autocorrelation analysis to distinguish between these selective regimes or even to detect departures from neutrality is dependent on the strength of the evolutionary force and the population structure. Weak selection or migration will not be apparent against the expected background of stochastic noise. Moreover, the population structure may generate sufficient stochastic variation such that even strong evolutionary forces may fail to be detected. This study uses computer simulation to examine the effects of kin-structured migration and three different selective regimes on the shape of spatial correlograms to assess the ability of this technique to detect different microevolutionary processes. Genetic variation among 8 loci is simulated in a linear set of 25 artificial populations. Kin-structured stepping-stone migration among adjacent populations is modeled; directional, balanced, and clinal selection, as well as neutral loci are considered. These experiments show that strong selection produces correlograms of the predicted shape. However, with an anthropologically reasonable population structure, considerable stochastic variation among correlograms for different alleles may still exist. This suggests the need for caution in inferring genetic process from spatial patterns. © 1994 Wiley-Liss, Inc.