亚热带森林啮齿类动物对林区两种植物果实的捕食和扩散研究——以宽阔水自然保护区为例

2007年9月至10月,以贵州省遵义市绥阳县宽阔水国家级自然保护区亚热带森林系统内食果(或食种子)啮齿类动物与肉果植物香港四照花Dendrobenthamia hongkongensis和干果植物西南山茶Camellia pitardii为研究对象,初步研究鼠类捕食对两种植物种子扩散的影响.结果表明啮齿动物对两种植物果实及种子的搬运存在较大差异:鼠类对于肉果植物主要表现为种子的散布者,香港四照花90%的种子被成功散布,但距离较靠近母树;鼠类对于干果植物则主要表现为种子的掠食者,超过90%的西南山茶种子被鼠类采食,仅极少数能够偶然幸存下来进入土壤种子库,鼠类对干果的平均搬运距离大于肉果.     

贝莱斯芽孢杆菌RJW-5-5的分离鉴定及细菌素、抗菌肽基因簇挖掘

[背景]化学防治污染日益严重,作物抗性、农药残留、病害再生现象越来越普遍,因此筛选新型生防菌株及研究其抗菌物质已成为热点.[目的]筛选出一株对禾旋孢腔菌等植物病原菌具有生防功能的贝莱斯芽孢杆菌,挖掘其调控合成细菌素、抗菌肽(RiPPs)的基因簇.[方法]通过分离筛选、对峙培养等方法筛选出菌株,通过全细胞脂肪酸和Biol...     

The non-MHC quantitative trait locus Cia5 contains three major arthritis genes that differentially regulate disease severity, pannus formation, and joint damage in collagen- and pristane-induced arthritis

Cia5 is a locus on rat chromosome 10 which regulates the severity of collagen- and pristane-induced arthritis (CIA and PIA). To refine the region toward positional identification, Cia5 subcongenic strains were generated and studied in PIA and CIA. The protective effect of the telomeric locus Cia5a was confirmed in both models. A second arthritis severity locus (Cia5d) was identified within the most centromeric portion of Cia5. DA.F344(Cia5d) rats had a significantly lower median arthritis severity index in PIA, but not in CIA, compared with DA. On histologic analyses DA.F344(Cia5a) and DA.F344(Cia5d) congenics with PIA preserved a nearly normal joint architecture compared with DA, including significant reduction in synovial hyperplasia, pannus, angiogenesis, inflammatory infiltration, bone and cartilage erosions. Cia5 and Cia5a synovial levels of IL-1beta mRNA were reduced. Although both DA.F344(Cia5) and DA.F344(Cia5a) rats were protected in CIA, the arthritis scores of DA.F344(Cia5) were significantly higher than those of DA.F344(Cia5a), suggesting the existence of a third locus where F344-derived alleles centromeric from Cia5a contribute to increased arthritis severity. The existence of the third locus was further supported by higher levels of autoantibodies against rat type II collagen in DA.F344(Cia5) congenics compared with DA.F344(Cia5a). Our results determined that Cia5 contains three major arthritis severity regulatory loci regulating central events in the pathogenesis of arthritis, and differentially influencing CIA and PIA. These loci are syntenic to regions on human chromosomes 17q and 5q implicated in the susceptibility to rheumatoid arthritis, suggesting that the identification of these genes will be relevant to human disease.     

发菜磷酸葡糖胺变位酶(glmM)对干旱胁迫的响应及其基因克隆

glmM编码的磷酸葡糖胺变位酶是肽聚糖合成前体的关键酶。为探究发菜glmM响应干旱胁迫的表达调控机制及明确其分子信息,本研究对干旱胁迫条件下发菜glmM在转录水平的差异表达进行了分析,并对glmM的表达水平、磷酸化修饰、乙酰化修饰和琥珀酰化修饰水平进行了检测,克隆了发菜glmM,进行了序列分析和原核表达。结果表明,干旱胁迫条件下,发菜glmM在转录水平上的表达量先增加后减少,glmM上调表达,glmM的磷酸化修饰水平逐渐增加,乙酰化修饰水平相对稳定,琥珀酰化修饰水平有明显变化。设计特异性引物克隆glmM基因,获得全长1416 bp发菜glmM基因,与肺衣(5183)glmM的核苷酸序列同源性为95%,氨基酸同源性为97%。将glmM在大肠杆菌中表达,获得一个51.45 kD的外源蛋白,MALDI-TOF-TOF/MS分析证明该蛋白为磷酸葡糖胺变位酶。研究结果为深入研究发菜glmM的分子信息、生物学功能及其响应干旱胁迫的分子机制提供帮助。     

Temperature Sensitivity and Basal Rate of Soil Respiration and Their Determinants in Temperate Forests of North China

The basal respiration rate at 10°C (R₁₀) and the temperature sensitivity of soil respiration (Q₁₀) are two premier parameters in predicting the instantaneous rate of soil respiration at a given temperature. However, the mechanisms underlying the spatial variations in R₁₀ and Q₁₀ are not quite clear. R₁₀ and Q₁₀ were calculated using an exponential function with measured soil respiration and soil temperature for 11 mixed conifer-broadleaved forest stands and nine broadleaved forest stands at a catchment scale. The mean values of R₁₀ were 1.83 µmol CO₂ m⁻² s⁻¹ and 2.01 µmol CO₂ m⁻² s⁻¹, the mean values of Q₁₀ were 3.40 and 3.79, respectively, for mixed and broadleaved forest types. Forest type did not influence the two model parameters, but determinants of R₁₀ and Q₁₀ varied between the two forest types. In mixed forest stands, R₁₀ decreased greatly with the ratio of coniferous to broadleaved tree species; whereas it sharply increased with the soil temperature range and the variations in soil organic carbon (SOC), and soil total nitrogen (TN). Q₁₀ was positively correlated with the spatial variances of herb-layer carbon stock and soil bulk density, and negatively with soil C/N ratio. In broadleaved forest stands, R₁₀ was markedly affected by basal area and the variations in shrub carbon stock and soil phosphorus (P) content; the value of Q₁₀ largely depended on soil pH and the variations of SOC and TN. 51% of variations in both R₁₀ and Q₁₀ can be accounted for jointly by five biophysical variables, of which the variation in soil bulk density played an overwhelming role in determining the amplitude of variations in soil basal respiration rates in temperate forests. Overall, it was concluded that soil respiration of temperate forests was largely dependent on soil physical properties when temperature kept quite low.     

云南萝芙木pnae基因全长克隆及其序列分析

根据已知的其他物种PNAE酶cDNA序列设计引物,采用RT-PCR技术从云南萝芙木叶片中扩增获得pnae基因部分cDNA序列即PNAE酶基因中间大片段,再用RACE技术获得其两端序列。序列拼接得到完整的1 004 bp的PNAE酶基因,根据获得的序列,分析得到795 bp的开放阅读框,编码264个氨基酸。序列分析显示,云南萝芙木中PNAE酶氨基酸序列与蛇根木中的该酶氨基酸序列同源性高达90%,但和其他植物物种中的PNAE酶氨基酸序列,以及其他物种间的PNAE酶氨基酸序列同源性都不高,在40%-60%之间,表明不同物种中PNAE酶氨基酸序列不具有全序列的高度同源性。进一步序列分析发现,在各植物的PNAE酶氨基酸序列中都存在两个高度保守的氨基酸区域,表明不同物种中PNAE酶存在共同的高度保守区段。     

Microscopic mechanism of DNA damage searching by hOGG1

The DNA backbone is often considered a track that allows long-range sliding of DNA repair enzymes in their search for rare damage sites in DNA. A proposed exemplar of DNA sliding is human 8-oxoguanine (^oG) DNA glycosylase 1 (hOGG1), which repairs mutagenic ^oG lesions in DNA. Here we use our high-resolution molecular clock method to show that macroscopic 1D DNA sliding of hOGG1 occurs by microscopic 2D and 3D steps that masquerade as sliding in resolution-limited single-molecule images. Strand sliding was limited to distances shorter than seven phosphate linkages because attaching a covalent chemical road block to a single DNA phosphate located between two closely spaced damage sites had little effect on transfers. The microscopic parameters describing the DNA search of hOGG1 were derived from numerical simulations constrained by the experimental data. These findings support a general mechanism where DNA glycosylases use highly dynamic multidimensional diffusion paths to scan DNA.     

HFRSV在平皿表面室温暴露后存活力的定量研究

将肾综合症出血热病毒布于玻璃平皿表面,室温条件下分别暴露0、30、60、90和120min,观察病毒的定量存活情况.结果在经过120min的暴露后,HFRSV的效价仍高达104.23 TCID50.这一结果为HFRS的流行病学及其防治研究提供了重要的基础数据.     

Robustness of Taylor’s law under spatial hierarchical groupings of forest tree samples

Testing how well Taylor's law (TL) describes spatial variation of the population density of a species requires grouping sampling areas (patches of habitat) into blocks so that a mean and a variance of the population density can be calculated over the patches in each block. The relationship between specific groupings and TL remains largely unknown. Here, using tree counts from a deciduous forest, we studied the effect of four biological methods of grouping sampling areas into blocks on the form and parameters of TL. Regardless of the method of grouping, the species-specific basal area densities obeyed TL, and the estimated slopes were not significantly different from one grouping method to another. Surprisingly, TL remained valid when four kinds of randomizations were performed to the biological groupings and tree census. These randomizations randomly assigned sampling areas to blocks, and/or randomized the species composition within or across sampling areas. We found that the form of TL was robust to different grouping methods and species randomizations, but its parameter values depended significantly on species compositions at sampling areas.