北京市怀沙-怀九河市级水生野生动物保护区鱼类物种多样性及其资源保护

怀沙河和怀九河是两条自然汇入北京怀柔水库的河流,被规划为北京市第一个市级水生野生动物保护区。2004年3月~2005年2月,作者对该保护区内野生鱼类资源进行了本底调查。调查区域内野生淡水鱼类共计24种(不计引入种),隶属于6目11科24属,以鲤形目鲤科鱼类为主,多为山区溪流小型鱼类。鱼类物种多样性在空间分布上有所不同,两河下游近水库河段物种多样性最高,这可能与两个不同生态环境交界处的边缘效应有关;其多样性在时间上春夏季高于秋冬季。结合区域内的生境特点,建议加强对核心区的保护力度,重新规划缓冲区和过渡区;在保护自然环境的同时,兼顾当地居民的经济利益,达到人与资源的和谐发展。     

奠基者效应对海南坡鹿迁地保护种群遗传多样性的影响

在迁地保护中,奠基者效应通常会导致新建种群与源种群的遗传分化,并使新建种群的遗传多样性低于源种群。海南坡鹿(Cervuseldi hainanus)是世界濒危种,野生种群仅分布在中国海南岛。由于栖息地破坏和过度狩猎,至20世纪70年代,这个物种仅剩26只,已经濒临绝灭,被列为国家一级保护动物。自1976年开始对海南坡鹿实施就地保护和迁地保护,该种群的数量从最初的26只增加到1600多只。本文采用10个微卫星位点对一个源种群(大田种群)和5个迁地种群(邦溪、甘什岭、枫木、金牛岭、文昌种群)的遗传多样性进行检测,结果发现6个种群的遗传多样性水平均较低(He≈0·3);5个迁地种群分别有1、3或5个单态位点,大田种群无单态位点;邦溪种群与大田种群遗传分化显著,而甘什岭种群与大田种群的遗传分化不显著。结果表明,奠基者效应导致种群的遗传多样性水平较低,并且对于不同迁地种群,影响也不相同。造成这些差异的因素有建群者数量、引种方式和建群种群的结构。该研究为今后在海南岛建立新的海南坡鹿迁地种群提供建议和参考,同时也为其他濒危物种的迁地保护提供理论指导。     

Analysis of the genusZea (Poaceae) using polymorphic chloroplast simple sequence repeats

We have used polymorphic chloroplast simple sequence repeats (cpSSRs) to analyse levels of diversity and relationships within the genusZea. Between two and nine alleles were found at 15 polymorphic loci and combining the data from these loci gave 32 haplotypes in the 37 accessions studied. Genetic differentiation between the two sections within the genus was calculated using theST statistic which showed that 70% of the total variation was found to exist between the sections. A phylogenetic analysis based on the ² distance metric showed a large split between the two sections and suggested multiple origins of modern cultivated maizeZea mays subsp.mays. The agreement of the phylogenetic tree with other molecular, morphological and karyological studies suggests that cpSSRs may have value in phylogenetic studies in plants.     

Genetic diversity and differentiation in Portuguese cattle breeds using microsatellites

Genotype data from 30 microsatellites were used to assess genetic diversity and relationships among 10 native Portuguese cattle breeds, American Charolais and the Brazilian Caracú. Hardy–Weinberg equilibrium was observed for all loci/population combinations except for five loci in Brava de Lide and one locus in Alentejana that exhibited heterozygote deficiency. Estimates of average observed and expected heterozygosities, total number of alleles (TNA) per breed and mean number of alleles (MNA) per locus/population were obtained. A total of 390 alleles were detected. TNA among Iberian cattle ranged from 170 to 237 and MNA ranged from 5.67 to 8.07. The highest observed heterozygosities were found in the Caracú, Maronesa, Garvonesa and Arouquesa and the lowest in Brava de Lide and Mirandesa. Estimation of population subdivision using Wright's F_ST index showed that the average proportion of genetic variation explained by breed differences was 9%. Neighbour‐joining phylogenetic trees based on D_A distances showed that the genetic relationships of present‐day Portuguese native breeds are consistent with historical origins in the Brown Concave (Arouquesa, Mirandesa, Marinhoa) and Red Convex (Mertolenga, Alentejana, Garvonesa, Minhota) evolutionary groups. The Iberian Black Orthoide group, represented by Brava de Lide and Maronesa, and the Barrosã breed appeared to be more closely related to the Brown Concave group but may represent a separate lineage. The Caracú breed was not found to be closely associated with any of the native Portuguese breeds.     

Variations in levels of clonality among Populus nigra L. stands of different ages

The evolution of genotypic diversity with population age remains poorly explored in clonal plant populations despite the potential for important shifts to occur through the course of time. Woody sprouting species are particularly under-represented in studies investigating intra-specific variations in levels of clonality from one locality to the next and through time. In this study we sought to determine the incidence and frequency of replicate genotypes in natural Populus nigra L. (Salicaceae) stands of different ages. Ten stands of this woody riparian sprouting species were selected in each of three distinct age groups (young, middle-aged and old) along a 30 km stretch of the River Garonne (south-west France). Leaf samples were collected from 15 neighbouring trees in each stand (450 samples in total) and replicate genotypes were identified using five SSR markers. Replicate genotypes were identified in two-thirds of all stands sampled (i.e. 50 of young stands, 100 of middle-aged stands and 50% of old stands). Young stands had significantly fewer replicated genotypes than middle-aged or old stands, while middle-aged stands had the greatest number of replicated genotypes. Replicate genotypes were most often found to occur as nearest neighbours and formed relatively small, discrete units (i.e. 2–4 trees growing in close proximity to one another). This suggests that asexual regeneration frequently occurs through flood-training in this species, although asexual regeneration from translocated fragments also evidently occurs as evidenced by 11 cases of replicate genotypes occurring in widely separated stands (up to 19 km apart). The results of this study highlight the need for a hierarchical sampling strategy in space and across age groups for an accureate understanding of the genotypic structure of woody sprouting species populations. Conservation and management of effective population sizes will benefit from better insight into not only spatial, but also temporal variations in levels of genotypic diversity.Co-ordinating editor: J. Tuomi     

Genetic diversity in German draught horse breeds compared with a group of primitive, riding and wild horses by means of microsatellite DNA markers

We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (H(o)) differed little among the heavy horse breeds (0.64-0.71), but was considerably lower than in the Hanoverian Warmblood or Icelandic Horse population. The mean number of alleles (N(A)) decreased more markedly with declining population sizes of German draught horse breeds (5.2-6.3) but did not reach the values of Hanoverian Warmblood (N(A) = 6.7). The coefficient of differentiation among the heavy horse breeds showed 11.6% of the diversity between the heavy horse breeds, as opposed to 21.2% between the other horse populations. The differentiation test revealed highly significant genetic differences among all draught horse breeds except the Mecklenburg and Saxon Thuringa Coldbloods. The Schleswig Draught Horse was the most distinct draught horse breed. In conclusion, the study demonstrated a clear distinction among the German draught horse breeds and even among breeds with a very short history of divergence like Rhenish German Draught Horse and its East German subpopulations Mecklenburg and Saxon Thuringa Coldblood.     

Genetic diversity and multilocus genetic structure in the relictual endemic herb<Emphasis Type="Italic"> Japonolirion osense</Emphasis> (Petrosaviaceae)

Plant clonality may greatly reduce effective population size and influence management strategies of rare and endangered species. We examined genetic diversity and the extent of clonality in four populations of the monotypic herbaceous perennial Japonolirion osense, which is one of the most rare flowering plants in Japan. Allozyme analysis revealed moderate levels of genetic variation, and the proportion of polymorphic loci (P=66.7%) was higher than the value for species with similar life-history traits. With four polymorphic loci, 19 multilocus genotypes were observed among 433 aerial shoot samples and 10 (52%) were found only in single populations. The proportion of distinguishable genotypes (PD=0.10) and Simpson's index of diversity (D=0.52) also exhibited moderate levels of genotypic diversity compared to other clonal plants, with genotype frequencies at Hardy-Weinberg equilibrium. The distributions of genotypes were often localized and they were mostly found within a radius of 5 m. Spatial autocorrelation analysis showed that shoot samples located 4 m apart were expected to be genetically independent. The results suggest that the spatial extent of genets was relatively narrow and thus the clonality was not extensive.     

The solubilization and biological activities of Aspergillus beta-(1 --> 3)-D-glucan

We have recently demonstrated that the cell wall beta-glucan of Candida albicans could be solubilized by sodium hypochlorite, followed by dimethylsulfoxide-extraction (NaClO-DMSO method). In this study, applying this method to Aspergillus spp., we prepared mycelial cell wall beta-glucan and examined its physical properties and immunotoxicological activity. The acetone-dried mycelia of Aspergillus spp. were oxidized by the NaClO-DMSO method. An analysis of (13)C NMR spectra revealed the preparations to be composed of alpha-(1 --> 3) and beta-(1 --> 3)-D-glucan. Also, the proportion of alpha-(1 --> 3) and beta-(1 --> 3)-D-glucan varied. Furthermore, a solubilized Aspergillus beta-glucan (ASBG) was prepared from OX-Asp by urea-autoclave treatment. ASBG showed limulus activity similar to Candida solubilized beta-glucan (CSBG), and there was little difference in the activity of ASBG between various Aspergillus spp. ASBG affected the production of IL-8 by human peripheral blood mononuclear cells (PBMC). ASBG should be useful for analyzing the clinical role of beta-glucan.     

Isolation, geographical diversity and insecticidal activity of Bacillus thuringiensis from soils in Spain

Bacillus thuringiensis is a spore-forming bacterium showing the unusual ability to produce endogenous crystals during sporulation that are toxic for some pest insects. This work was performed to study the composition, ecological distribution and insecticidal activity of isolates of this entomopathogenic bacterium from the Spanish territory. Using a standard isolation method, B. thuringiensis was isolated from 115 out of 493 soil samples collected in the Iberian Peninsula and the Canary and Balearic Archipelagos. The percentages of samples with B. thuringiensis were 31.7, 27.6 and 18.5 and the B. thuringiensis index 0.065, 0.067 and 0.11 for the Iberian Peninsula, Canary and Balearic Archipelagos, respectively. The prairies were shown to be the worst source of B. thuringiensis while forests, urban and agricultural habitats showed similar percentages. Strain classification based on H-antigen agglutination showed a great diversity among the Spanish isolates, which were distributed among 24 subspecies, including three new ones andaluciensis, asturiensis and palmanyolensis. We differentiated 65 different protein profiles of spore-crystal mixtures by sulfate-polyacrylamide gel electrophoresis and we selected 109 isolates representative of these profiles to evaluate their insecticidal activity against insects from the Orders Orthoptera, Dictyoptera, Coleoptera, Lepidoptera and Diptera. We found variable percentages of isolates active against Coleoptera and Lepidoptera, one isolate highly active against mosquito larvae and for the first time, three isolates active against cockroaches and locusts.     

Effects of anthropogenic disturbance on plant diversity and community structure of a sacred grove in Meghalaya, northeast India

This study analyses the effects of anthropogenic disturbance on plant diversity and community attributes of a sacred grove (montane subtropical forest) at Swer in the East Khasi Hills district of Meghalaya in northeast India. The undisturbed, moderately disturbed and highly disturbed stands were identified within the sacred grove on the basis of canopy cover, light interception and tree (cbh 15 cm) density. The undisturbed forest stand had >40% canopy cover, >50% light interception and a density of 2103 trees per hectare, whereas the highly disturbed stand had <10% canopy cover, <10% light interception and 852 trees per hectare. The moderately disturbed stand occupied the intermediate position with respect to these parameters. The study revealed that the mild disturbance favoured species richness, but with increased degree of disturbance, as was the case in the highly disturbed stand, the species richness markedly decreased. The number of families of angiosperms was highest (63) in the undisturbed stand, followed by the moderately (60) and highly disturbed (46) stands. The families Rubiaceae, Asteraceae and Poaceae were the dominant families in the sacred forest. Rubiaceae was represented by 11, 14 and 10 species in the undisturbed, moderately disturbed and highly disturbed stands, respectively, whilst the family Asteraceae had 16 species in the moderately disturbed stand and 14 species in the highly disturbed stand. The number of families represented by a single species was reduced significantly from 33 in the undisturbed stand to 23 in the moderately and 21 in the highly disturbed stand. The similarity index was maximum (71%) between the undisturbed and moderately disturbed stand and minimum (33%) between the undisturbed and highly disturbed stands. The Margalef index, Shannon diversity index and evenness index exhibited a similar trend, with highest values in the moderately disturbed stand. In contrast, the Simpson dominance index was highest in the highly disturbed stand. There was a sharp decline in tree density and basal area from the undisturbed (2103 trees ha^–1 and 26.9 m² ha^–1) to the moderately disturbed (1268 trees ha^–1 and 18.6 m² ha^–1) and finally to the highly disturbed (852 trees ha^–1 and 7.1 m² ha^–1) stand. Density–girth curves depicted a successive reduction in number of trees in higher girth classes from the undisturbed to the moderately and highly disturbed stands. The log-normal dominance–distribution curve in the undisturbed and moderately disturbed stands indicated the complex and stable nature of the community. However, the short-hooked curve obtained for the highly disturbed stand denoted its simple and unstable nature.