Habitat utilization by ovipositing females and larvae of the Marsh fritillary (Euphydryas aurinia) in a mosaic of meadows and croplands

The butterfly Euphydryas aurinia occurs as a classical metapopulation in Yanjiaping village, Heibei province, China. In the patch network under study there were 38 habitat patches. Most patches were uncultivated, consisting of meadows and fallows, while others had been cultivated, i.e., used as small croplands. In the cultivated patches, the habitat for the butterfly can be classified into two types: meadow type (MTH) and cropland type (CTH). In contrast, the uncultivated habitat patches consists only of MTH. We examined the habitat utilization of ovipositing females and larvae of E. aurinia to assess the effect of mixed land use on the butterfly’s occurrence. More egg clusters and pre-hibernating larval groups were distributed throughout CTH than MTH. This dependence on CTH may be due to the preference of egg-laying females for large-sized host plants, which were mainly concentrated in CTH. Compared to the MTH, the mortality rate in CTH was lower. Therefore, for both eggs and pre-hibernating larvae, the quality of CTH was higher than that of MTH. The conditions in MTH, on the other hand, were important for the development of post-hibernation larvae. A combination of extensive farming and animal husbandry has created a mosaic of meadows and croplands in the habitats studied here, which is typical of rural areas in some developing countries. This study implies that patchy land use typical of traditional agriculture facilitates the long-term persistence of E. aurinia.     

植被覆盖度和综合治理对纸坊沟流域土壤氮素流失的影响

同小流域土壤侵蚀一样,小流域土壤氮素随洪流流失也受到植被覆盖度的影响,通常经过调整小流域内土地利用结构以达到控制水土流失。该研究以8.27 km2纸坊沟流域和1:400比例流域模型为研究对象,研究植被覆盖度和综合治理对纸坊沟流域土壤氮素流失的影响。结果表明:在模拟降雨下,当流域植被覆盖度分别为60%、40%、20%和0时,流域模型铵态氮流失量分别为87.08、44.31、25.16和13.71 kg/km2,硝态氮为85.50、74.05、63.95和56.23 kg/km2,全氮为0.81、1.18、1.98和7.51 t/km2;在自然降雨下,1998年与1992年相比,全流域年土壤侵蚀量为1 086 t/km2和1 119 t/km2,氮素流失量为8 758.5和7 562.2 kg,减少了15.8%,其中农地减少了52.0%。流域对降水中的矿质氮具有过滤作用,硝态氮的过滤作用明显高于铵态氮。洪流泥沙中<20 mm微团聚体富集造成了泥沙有机质和全氮的富集。植被覆盖虽能有效地减少流域土壤侵蚀和全氮的流失,却能增加土壤矿质氮的流失。坡地退耕还林草可显著减少流域土壤氮素流失。     

植物学野外实习教学改革实践与探讨

探讨植物学野外实习教学改革与实践,改革野外实习内容和形式,引导学生主动探索自然界,主动获得植物学知识的能力。加强野外实习,培养学生学习植物学基本研究方法。野外实习结合科研活动,提高学生科学素质和创造能力。提出实施野外实习改革的奈件,为提高植物学野外实习教学质量提供参考。     

Distribution and Organization of AA Genome- specific and Tandemly Repetitive Sequences in Chinese Common Wild Rice and Cultivated Rice

Repetitive DNA sequences are useful molecular markers for studying plant genome evolution and species diversity. The authors report the isolation and characterization of repetitive DNA sequences (pOs139) from Oryza sativa cuhivars "Zhaiyeqing". By Southern blot analysis, the authors discovered that pOs139 sequences were organized not only tandemly, but also highly specifc for the AA genome of Oryza genus. Sequence analysis revealed that the clone pOs139 contains a 355 bp repetitive unit. The genomic DNA of 29 Chinese common wild accessions, and 43 cultivated rice accessions, were analyzed by Southern blot with pOs139 as a probe. The results illustrated that there was significant difference in hybridization patterns between japonica and indica subspecies. Hybridization bands of indica subspecies were much more than those of japonica, and the Chinese common wild rice was similar to indica in hybridization patterns. The copy number estimated by dot blot hybridization analysis indicated that a considerable degree of variation existed among different accessions of O. sativa and the Chinese common wild rice. It is interesting to note that japonica subspecies contains relatively low copy numbers of pOs139-related repetitive DNA sequences, while the indica and Chinese common wild rice contain relatively high copy numbers.     

ITS1 Sequences of Nuclear Ribosomal DNA in Wild Rices and Cultivated Rices of China and Their Phylogenetic Implications

he first internal transcribed spacer (ITS1) of nuclear ribosomal DNA of three wild rice species and two subspecies of cultivated rice, which are distributed in China, was amplified using PCR technique and sequenced with automated fluorescent sequencing. The sequences of ITS1 ranged from 193 bp to 218 bp in size and G/C content varied from 69.3%to 72.7%. In pairwise comparison among the five taxa, sequence site divergence ranged from 1.5 % to 10.6%. Phylogenetic analysis of ITS1 sequences using Wagner parsimony generated a single well-resolved tree, which revealed that Oryza rufipogon was much more closely related to cultivated rice species than to the other two wild species. Oryza granulata was less closely related to either cultivated rice species or the other two wild species, and might be a unique and isolated taxon in the genus Oryza. The phylogenetic relationships of the three wild rice species and two cultivated rice subspecies inferred from ITS1 sequences is highly concordant with those based on the molecular evidence from isozyme, chloroplast DNA (cpDNA), mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) of the genus Oryza.     

医学微生物学课程思政改革的实践与思考

专业课程是课程思政建设的基本载体,课程思政建设是课程教学改革的根本任务.医学微生物学是医学生的一门专业基础课程,教学内容涉及与人民生活息息相关的病原微生物,实用性强.紧密结合医学微生物学课程内容和人民健康需求,开展课程思政教育资源体系建设,强化学生知识学习和思想教育,达到"立德树人"的培养目标.文章介绍了围绕医学微生物...     

A Multinomial Model for the Quality Control of Colony Counting Procedures

The so‐called good‐laboratory‐practice (GLP) test provides an experimental design and appropriate statistical analysis for the problem of analyst performance assessment in microbiological laboratories. For a given sample material multiple dilution series are generated yielding colony counts from several dilution levels. Statistical evaluation is based on the assumption of Poisson‐distributed colony forming units. In this paper a new model based on conditional binomial and multinomial distributions is presented and it is shown how it is related to the standard model which assumes Poisson‐distributed colony counts. The effects of common working errors on the statistical evaluation of the GLP‐test are investigated.     

Application of the impact pathway analysis in the context of LCA

Current LCA practice is mass oriented, i.e. is focused on the amount of chemicals released, disregarding place and time of release. Life cycle impact assessment aims at evaluating potential impacts, and a variety of weighting schemes is discussed to he used for ranking and aggregation of impacts. To establish a closer link between the quantity of a burden released and a decision making context, we propose to follow a detailed impact pathway analysis to estimate actual impacts for some priority impact categories, and use measured individuals’ preferences for impact valuation. Results from a case study illustrate the relevance of site specific impact assessment in the context of LCA.     

Methodologies for the extraction and analysis of konjac glucomannan from corms of Amorphophallus konjac K. Koch

Here we present a comparison of commonly used methodologies for the extraction and quantification of konjac glucomannan (KGM). Compositional analysis showed that the purified konjac flour (PKF) produced using a modified extraction procedure contained 92% glucomannan, with a weight average molecular weight (M_w), polydispersity index (PDI) and degree of acetylation (DA) of 9.5 ± 0.6 × 10⁵ g mol⁻¹, 1.2 and 2.8 wt.%. These data, plus Fourier-transform infrared spectral (FTIR) and zero shear viscosity analyses of the extract (PKF) were all consistent with the literature. Comparison of three existing methodologies for the quantitative analysis of the KGM content of the PKF, namely 3,5-dinitrosalicylic acid (3,5-DNS), phenol-sulphuric acid and enzymatic colorimetric assays; indicated that the 3,5-DNS colorimetric assay was the most reproducible and accurate method, with a linear correlation coefficient of 0.997 for samples ranging from 0.5 to 12.5 mg/ml, and recoveries between 97% and 103% across three spiking levels (250, 500 and 750 μg/g) of starch. These data provide the basis of improved good laboratory practice (GLP) for the commercial extraction and analysis of this multifunctional natural polymer.