小黄皮叶挥发油的化学成分

利用水蒸气蒸馏法提取小黄皮叶挥发油,运用毛细管气相色谱-质谱联用法对挥发油进行了分析,分离出40个峰,鉴定了其中的37种成分,所鉴定成分占挥发油总量的99.87%,其主要化学成分为单萜及倍半萜类化合物。     

Antibacterial activity of triterpene acids and semi-synthetic derivatives against oral pathogens

Triterpene acids (ursolic, oleanoic, gypsogenic, and sumaresinolic acids) isolated from Miconia species, along with a mixture of ursolic and oleanolic acids and a mixture of maslinic and 2-a-hydroxyursolic acids, as well as ursolic acid derivatives were evaluated against the following microorganisms: Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, Streptococcus salivarius, Streptococcus sobrinus, and Enterococcus faecalis, which are potentially responsible for the formation of dental caries in humans. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC) during the evaluation of the antibacterial activity. All the isolated compounds, mixtures, and semi-synthetic derivatives displayed activity against all the tested bacteria, showing that they are promising antiplaque and anticaries agents. Ursolic and oleanolic acids displayed the most intense antibacterial effect, with MIC values ranging from 30 microg/mL to 80 microg/mL. The MIC values of ursolic acid derivatives, as well as those obtained for the mixture of ursolic and oleanolic acids showed that these compounds do not have higher antibacterial activity when compared with the activity observed with either ursolic acid or oleanolic acid alone. With regard to the structure-activity relationship of triterpene acids and derivatives, it is suggested that both hydroxy and carboxy groups present in the triterpenes are important for their antibacterial activity against oral pathogens.     

Infection Process of Botrytis cinerea on Eucalypt Leaves

This study aimed to elucidate the infection process of Botrytis cinerea on eucalypt leaves. Tests were conducted to evaluate the influence of leaf side (adaxial or abaxial), leaf age and luminosity on conidial germination, appressorium formation and grey mould (GM) severity. The adaxial and abaxial surfaces of detached eucalypt leaves were inoculated with a conidial suspension of B. cinerea and kept under constant light or dark. Subsequently, the adaxial surface of young and old leaves was inoculated and kept in the dark. To evaluate the percentage of conidia germination and appressorium formation, leaf samples were collected 6 hours after inoculation (hai), clarified (alcohol and chloral hydrate) and evaluated under a light microscope. The severity of GM was assessed 10 days after inoculation. For scanning electron microscopy analysis, samples were collected from 2 to 168 hai. A higher percentage of conidia germination (92%) and GM severity (21%) occurred on the adaxial surfaces of leaves kept in the dark. There was no statistical difference between the surfaces of young and old leaves for conidia germination. No appressorium was formed by B. cinerea. The GM severity on young leaves (17.3%) was 34 times higher than on old leaves (0.5%). The micrographs showed germinating conidia emitting 1–4 germ tubes in samples at 4 hai. The fungus penetration occurred through intact leaf surfaces, and both extra‐ and intracellular colonization of the mesophyll cells by the hyphae of the pathogen were observed at 120 hai. Sporulation occurred on the adaxial and abaxial surfaces (macronematous conidiophores) and below the epidermis (micronematous conidiophores).     

Allelic frequencies and statistical data obtained from 12 codis STR loci in an admixed population of the Brazilian Amazon

The allelic frequencies of 12 short tandem repeat loci were obtained from a sample of 307 unrelated individuals living in Macapá, a city in the northern Amazon region, Brazil. These loci are the most commonly used in forensics and paternity testing. Based on the allele frequency obtained for the population of Macapá, we estimated an interethnic admixture for the three parental groups (European, Native American and African) of, respectively, 46%, 35% and 19%. Comparing these allele frequencies with those of other Brazilian populations and of the Iberian Peninsula population, no significant distances were observed. The interpopulation genetic distances (F(ST) coefficients) to the present database ranged from F(ST) = 0.0016 between Macapá and Belém to F(ST) = 0.0036 between Macapá and the Iberian Peninsula.     

利用恒河婴猴模型对肠道病毒71型传播感染特征的生物学分析

本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...     

EV71灭活疫苗（人二倍体细胞）在恒河猴婴猴模型中的免疫保护性分析

肠道病毒71型作为引起儿童群体常见传染性手足口病（HFMD）的主要病原,具有导致少量感染个体出现脑炎等神经系统病变以及相关心肺功能衰竭的病理学特性．因此其预防性疫苗的研发具有重要的公共卫生意义．在前期工作的基础上,一种EV71灭活病毒疫苗（人二倍体细胞）在本研究中基于恒河猴婴猴模型进行了相应的免疫保护性分析．以160EU剂量对2～3月龄婴猴进行0,4周免疫后,动物在第4周接受了剂量为10。～CCID50的病毒经呼吸道的攻击．对病毒攻击后动物在14天内的临床症状、血液生物学、器官病原学分布以及病理学检测的动态观察表明,经疫苗免疫的动物未出现对照动物所具有的特征性临床表现,其血液生物学及病理学检测均无异常．同时,器官病原学分布亦呈阴性．结合动物中和抗体的明确增长及对照动物的综合表现分析,本文的工作证实了该EV71灭活病毒疫苗（人二倍体细胞）在恒河猴婴猴体内的免疫保护性．     

Snake population venomics and antivenomics of Bothrops atrox: Paedomorphism along its transamazonian dispersal and implications of geographic venom variability on snakebite management

We describe two geographically differentiated venom phenotypes across the wide distribution range of Bothrops atrox, from the Colombian Magdalena Medio Valley through Puerto Ayacucho and El Paují, in the Venezuelan States of Amazonas and Orinoquia, respectively, and S?o Bento in the Brazilian State of Maranh?o. Colombian and Venezuelan venoms show an ontogenetic toxin profile phenotype whereas Brazilian venoms exhibit paedomorphic phenotypes. Venoms from each of the 16 localities sampled contain both population-specific toxins and proteins shared by neighboring B. atrox populations. Mapping the molecular similarity between conspecific populations onto a physical map of B. atrox range provides clues for tracing dispersal routes that account for the current biogeographic distribution of the species. The proteomic pattern is consistent with a model of southeast and southwest dispersal and allopatric fragmentation northern of the Amazon Basin, and trans-Amazonian expansion through the Andean Corridor and across the Amazon river between Monte Alegre and Santarém. An antivenomic approach applied to assess the efficacy towards B. atrox venoms of two antivenoms raised in Costa Rica and Brazil using Bothrops venoms different than B. atrox in the immunization mixtures showed that both antivenoms immunodepleted very efficiently the major toxins (PIII-SVMPs, serine proteinases, CRISP, LAO) of paedomorphic venoms from Puerto Ayacucho (Venezuelan Amazonia) through S?o Bento, but had impaired reactivity towards PLA(2) and P-I SVMP molecules abundantly present in ontogenetic venoms. The degree of immunodepletion achieved suggests that each of these antivenoms may be effective against envenomations by paedomorphic, and some ontogenetic, B. atrox venoms.     

Semi-extended solution structure of human myeloma immunoglobulin D determined by constrained X-ray scattering

Human immunoglobulin D (IgD) occurs most abundantly as a membrane-bound antibody on the surface of mature B cells (mIgD). IgD possesses the longest hinge sequence of all the human antibody isotypes, with 64 residues connecting the Fab and Fc fragments. A novel rapid purification scheme of secreted IgD from the serum of an IgD myeloma patient using thiophilic (T-gel) and lectin affinity chromatography gave a stable, homogeneous IgD preparation. Synchrotron X-ray scattering and analytical ultracentrifugation of IgD identified the solution arrangement of its Fab and Fc fragments, and thereby its hinge structure. The Guinier X-ray radius of gyration R(G) of 6.9(+/-0.1)nm showed that IgD is more extended in solution than the immunoglobulin subclass IgA1 (R(G) of 6.1-6.2nm). Its distance distribution function P(r) showed a single peak at 4.7nm and a maximum dimension of 23nm. Velocity experiments gave a sedimentation coefficient of 6.3S, which is similar to that for IgA1 at 6.2S. The complete IgD structure was modelled using molecular dynamics to generate IgD hinge structures, to which homology models for the Fab and Fc fragments were connected. Good scattering curve fits were obtained with 18 semi-extended best fit IgD models that were filtered from 8500 trial models. These best-fit models showed that the IgD hinge does not correspond to an extended polypeptide structure. The averaged solution structure arrangement of the Fab and Fc fragments in IgD is principally T-shaped and flexible, with contribution from Y-shaped and inverted Y-shaped structures. Although the linear sequence of the IgD hinge is much longer, comparison with previous scattering modelling of IgA1 and IgA2(m)1 suggests that the hinge of IgA1 and IgD are more similar than might have been expected, Both possess flexible T-shaped solution structures, probably reflecting the presence of restraining O-linked sugars.