Dynamics of Competition in Populations of Carrot (Daucus carota)

Populations of carrot (Daucus carota) were raised over a widerange of densities (79–5763 plants m^-2) to examine thedynamics of competition in terms of yield–density relationshipsand size variability, and to investigate the effects of nutrientsupply on competition. While the relationship between shootyield and density was asymptotic, the relationship between rootand total yield and density tended to be parabolic. For a giventime and density series the relationship between yield per unitarea and density could best be described by the model: y=w_mD_(1+aD)^b wherey is the yield per unit area,D is density,w_m, a andb arefitted parameters. The parametersw_m anda increased over timebut nutrient availability affected onlyw_m. An extension of thebasic yield-density model is proposed to describe the dynamicsof the yield–density relationship over time: y=kD_{[1+cexp(-rt)]{1+}     

低温驯化对布氏田鼠小肠黏膜结构和黏膜免疫相关细胞的影响

环境温度的变化影响野生啮齿动物的消化道形态与功能。小肠是吸收营养成分的主要部位,其结构和功能具有可塑性。为了解小肠黏膜的结构和功能对环境温度变化的响应机制,以布氏田鼠为研究对象,比较了低温组和常温组动物小肠黏膜的组织结构和小肠黏膜免疫相关细胞的数目。结果显示：（1）低温组布氏田鼠的十二指肠、空肠和回肠的绒毛长度及绒毛长度与隐窝深度的比值均高于对照组;（2）低温驯化使布氏田鼠小肠上皮内淋巴细胞的数量增加;（3）低温驯化使布氏田鼠十二指肠、空肠和回肠的杯状细胞数量均显著增加。结果表明,在低温环境下布氏田鼠的小肠黏膜结构和免疫细胞的数量发生了可塑性变化,这可能与低温环境下的高能量需求和免疫功能的变化有关。     

Complete genome sequencing of exopolysaccharide-producing Lactobacillus plantarum K25 provides genetic evidence for the probiotic functionality and cold endurance capacity of the strain

Lactobacillus plantarum (L. plantarum) K25 is a probiotic strain isolated from Tibetan kefir. Previous studies showed that this exopolysaccharide (EPS)-producing strain was antimicrobial active and cold tolerant. These functional traits were evidenced by complete genome sequencing of strain K25 with a circular 3,175,846-bp chromosome and six circular plasmids, encoding 3365 CDSs, 16 rRNA genes and 70 tRNA genes. Genomic analysis of L. plantarum K25 illustrates that this strain contains the previous reported mechanisms of probiotic functionality and cold tolerance, involving plantaricins, lysozyme, bile salt hydrolase, chaperone proteins, osmoprotectant, oxidoreductase, EPSs and terpenes. Interestingly, strain K25 harbors more genes that function in defense mechanisms, and lipid transport and metabolism, in comparison with other L. plantarum strains reported. The present study demonstrates the comprehensive analysis of genes related to probiotic functionalities of an EPS-producing L. plantarum strain based on whole genome sequencing.     

粉花绣线菊复合群的化学分类研究

以粉花绣线菊复合群中二萜及二萜生物碱的结构特征,仿生合成及化学的相关性为基础,结合地理分布以及细胞学和形态学方面的研究资料,讨论粉花经菊复合群的化学分类,（１）具缩醛和二萜可能是绣线菊二萜生物碱的生源合成前体,（２）粉花绣线菊复合群是绣线菊属中特殊的,相对独立的类群;（３）我国西南尤其是横断山区是该复合群近代分化中心,有要能是起源中心;（４）对某些变种进行归并。     

小脑间位核和顶核对下丘脑外侧区神经元电活动的影响

电刺激猫小脑问位核和顶核可以影响下丘脑外侧区神经元的电活动,其中有一些神经元是葡萄糖敏感神经元.这一结果揭示小脑不仅具有经典的躯体运动调节功能,同时也可以通过小脑-下丘脑通路参与机体非躯体活动的调节.     

A novel and highly efficient production system for recombinant adeno-associated virus vector

Recombinant adeno-associated virus(rAAV) has proven to be a promising gene delivery vector for human gene therapy. However, its application has been limited by difficulty in obtaining enough quantities of high-titer vector stocks. In this paper, a novel and highly efficient production system for rAAV is described. A recombinant herpes simplex virus type 1(rHSV-1) designated HSV1-rc/△UL2, which expressed adeno-associated virus type2(AAV-2) Rep and Cap proteins, was constructed previously. The data confirmed that its functions were to support rAAV replication and packaging, and the generated rAAV was infectious. Meanwhile, an rAAV proviral cell line designated BHK/SG2, which carried the green fluorescent protein(GFP) gene expression cassette, was established by transfecting BHK-21 cells with rAAV vector plasmid pSNAV-2-GFP. Infecting BHK/SG2 with HSV1-rc/△UL2 at an MOI of 0.1 resulted in the optimal yields of rAAV, reaching 250 transducing unit(TU) or 4.28×104 particles per cell. Therefore, compared with the conventional transfection method, the yield of rAAV using this "one proviral cell line, one helper virus" strategy was increased by two orders of magnitude. Large-scale production of rAAV can be easily achieved using this strategy and might meet the demands for clinical trials of rAAV-mediated gene therapy.     

Investigation on the Interaction of Hydroxyethyl Starch 130/0.4 (Voluven) and Serum Albumin for Pharmacokinetic and Toxicological Implications

The interaction of hydroxyethyl starch 130/0.4 (Voluven) with human serum albumin (HSA) has been investigated by fluorescence (steady state and synchronous), Fourier transforms infrared (FT‐IR), and circular dichroism (CD) spectroscopies. Analysis of the fluorescence quenching data of HSA by Voluven using the Stern–Volmer method revealed the formation of 1:1 ground‐state complex. Evaluation of binding parameters and binding energy indicated that the binding reaction was exothermic. On the basis of fluorescence measurements, it was concluded that electrostatic forces play a crucial role in stabilizing the complex. The binding distance was calculated by using Förster resonance energy transfer (FRET) theory. The conformational changes of HSA were obtained qualitatively as well as quantitatively using synchronous fluorescence, FT‐IR, and CD. The HSA underwent partial unfolding in the presence of Voluven.