Flavonoids from Seeds of Camellia semiserrata Chi. and Their Estrogenic Activity

Two new flavonol glycosides and three known flavonoids were isolated from seeds of Camellia semiserrata Chi. The structures of these new flavonol glycosides were established as kaempferol 3-O-[(2'''',3'''',4''''-triacetyl)-α-L-rhamnopyranosyl(1→3)(2''',4'''-diacetyl)-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside] and kaempferol 3-O-[(3'''',4''''-diacetyl)-α-L-rhamnopyranosyl(1→3)(2''',4'''-diacetyl)-α-L-rhamnopyranosyl(1→6)-β-D-glucopyranoside] by spectroscopic methods. The estrogenic activity of these compounds was investigated by a recombinant yeast screening assay.     

Penetration and Development of Meloidogyne arenaria on Two New Grape Rootstocks

Penetration, development, and reproduction of a virulent ''Harmony'' population of Meloidogyne arenaria was studied on two nematode-resistant grape rootstocks 10-17A and 6-19B. ''Cabernet Sauvignon'' was used as a susceptible control for comparison. Plants were inoculated with 100 freshly hatched second-stage juveniles (J2) of M. arenaria. Greater numbers of J2 penetrated roots of ''Cabernet'' than 10-17A, and none penetrated roots of 6-19B 4 days after inoculation (DAI). At 7 DAI, vermiform J2 advanced to sausage-shaped J2 in roots of ''Cabernet,'' penetrated roots of 6-19B, and had egressed from roots of 10-17A. Resistant rootstocks expressed hypersensitive responses to penetrating J2 along the root epidermis, among the cortical cells, and along the differentiating vascular bundles. At 13 DAI, 68% of the J2 had attained globose stage in roots of ''Cabernet,'' whereas there was no development of vermiform J2 in roots of the other two rootstocks. The nematodes reproduced only in roots of ''Cabernet.'' Lack of development of J2 in roots of the two resistant grape rootstocks might be the result of a hypersensitive response to J2 feeding.     

Parasitic Variability of Meloidogyne incognita Populations on Susceptible and Resistant Cotton

Root gall induction and egg production by the four recognized host races and two cytological races of Meloidogyne incognita were compared on cotton Gossypium hirsutum cvs. Deltapine 16 (root-knot susceptible) and Auburn 634 (highly resistant). The 12 nematode populations included in the study were from various parts of the world. No population increases occurred on the highly resistant cultivar. After 45 days, populations of host races 1 and 2 induced slight root galling on both cuhivars with only limited reproduction. Host race 4 populations induced moderate root galling with higher reproduction on Deltapine 16 than that of race 1 or race 2 populations. Host race 3 populations induced severe root galling with population density increases of 7-30-fold. In a complementary study, 24 cotton cultivars or breeding lines were compared for suitability as hosts for a typical population of M. incognita race 3. The poorest hosts, ''Aubnru 623,'' ''Auburn 634,'' and ''McNair 220,'' yielded fewer eggs after 45 days than were added initially. The best hosts - ''M-8.'' ''DES 24-8,'' ''McNair 235,'' and ''Coker 20l'' - yielded > 5 times as many eggs as were added initially.     

Optimum Initial Inoculum Levels for Evaluation of Resistance in Tomato to Meloidogyne spp. at Two Different Soil Temperatures

The effects of Meloidogyne incognita or M. javanica at five initial inoculum levels of 20, 100, 200, 1,000, and 2,000 eggs and infective juveniles per seedling on ''Floradade,'' ''Nemarex,'' ''Patriot,'' and ''PI 129149-2(sib)-5'' tomatoes maintained at 25 or 32.5 C were studied. The number of egg masses on roots of the susceptible cultivar Floradade was similar for both species of root-knot nematodes at either 2.5 or 32.5 C soil temperatures. At 25 C, very low numbers of egg masses were produced by both species of root-knot nematodes on Nematex, Patriot, and Lycopersicon peruvianum PI 129149-2(sib)-5. At 32.5 C, the best inoculum level for assessing resistance in these tomato genotypes was 200 eggs and infective juveniles per seedling. With 28 days of incubation, this temperature and inoculum level produced quantitative differences in resistance for both species of Meloidogyne.     

Resistance of Some Vitis Rootstocks to Xiphinema index

Thirty-eight grapevine (Vitis spp.) rootstocks were screened in pots for resistance to the dagger nematode, Xiphinema index, from 1979 to 1981. Resistance ratings were based on visible root symptoms and on changes in the nematode populations over 16 months. Nineteen of the 23 Californian hybrid rootstocks tested were resistant, as were ''Harmony'','' ''Freedom,'' ''Schwarzmann,'' and ''3309.'' Two hybrids of V. rufotomentosa, ''171-52'' and ''176-9,'' were possibly immune to X. index. The rootstocks ''ARG 1,'' '' 110 R,'' ''1202,'' and ''1616,'' which are used commercially for phylloxera resistance were susceptible.     

东莞市人工景观结构与连接度的协整性及因果关系

城市人工景观特征逐步向城市外围自然及半自然景观渗透。近年来对快速城市化地区的景观格局特征定量化研究很多,但侧重于景观格局特征的简单分析和描述,忽略了城市空间扩展过程中,城市人工景观结构与景观连接度动态变化过程中之间的内部联系。以东莞市1988—2009年城市人工景观为研究对象,通过计算并分析景观结构与景观连接度指数,利用计量经济学中的协整概念与格兰杰因果检验方法并详细分析了这两类指数之间的具体关系。研究结果表明:(1)所选取的景观结构指数与景观连接度指数能较好地描述东莞市城市人工景观时空格局变化过程;(2)人工景观斑块类型面积(CA)与可能连通性指数(PC)存在协整关系。景观聚集度指数(AI)、蔓延度指数(CONTAG)与景观连通性指数(IIC与PC)也存在协整关系,即这些变量之间确实存在长期均衡关系;(3)格兰杰因果关系检验中,在不同滞后期的情况下,大部分的结果表明景观连接度指数(IIC与PC)是景观结构指数(CA、AI、CONTAG)的格兰杰成因,说明景观连接度指数信息有助于预测景观结构指数的变化。     

人工诱导海南龙血竭的化学成分研究

为了解人工诱导海南龙血树(Dracaena cambodiana)所产血竭的化学成分,从其乙醇提取物中分离得到10个化合物,经波谱分析分别鉴定为socotrin-4?-ol(1)、homoisosocotrin-4?-ol(2)、(E)-3-(3,4-dihydroxybenzylidene)-7-hydroxy-chroman-4-one(3)、5-hydroxy-7-methoxy-3-(4?-hydroxybenzyl)-4-chromanone (4)、3-去氧苏木查耳酮(5)、苏木查耳酮(6)、7,4?-二羟基黄酮(7)、7,4?-二羟基-8-甲基黄酮(8)、丁香树脂醇(9)和邻苯二甲酸二(2-乙基己基)酯(10)。化合物1～10均为首次从人工诱导海南龙血树所产血竭中分离得到,其中化合物8为新天然产物,化合物3～6为首次从血竭中分离得到。化合物7和8对耐甲氧西林金黄色葡萄球菌具有生长抑制作用。     

A DNA binding motif coordinating synthesis and degradation in proofreading DNA polymerases.

The functional significance of the conserved motif ''YxGG/A'', located between the 3''-5'' exonuclease and polymerization domains of eukaryotic-type DNA polymerases, has been studied by site-directed mutagenesis in phi29 DNA polymerase. Single substitutions at this region were obtained, and 11 phi29 DNA polymerase mutant derivatives were overproduced in Escherichia coli and purified to homogeneity. Nine mutants showed an altered polymerase/3''-5'' exonuclease balance on a template/primer DNA structure, giving rise to three different mutant phenotypes: (i) favored polymerization (high pol/exo ratio); (ii) favored exonucleolysis (low pol/exo ratio); and (iii) favored exonucleolysis and null polymerization. Interestingly, these three different phenotypes could be obtained by mutating a single amino acid at the ''YxGG/A'' motif. All different phenotypes could be directly related to defects in DNA binding at a particular active site. Thus, a high pol/exo ratio was related to a poor stability at the 3''-5'' exonuclease active site. On the contrary, a low pol/exo ratio or null polymerization capacity was related to a poor stability at the polymerization active site and either a normal or an increased accessibility to the exonuclease active site. These results allow us to propose that this motif, located in the connecting region between the N-terminal and C-terminal domains, has a primary role in DNA binding, playing a critical role in the coordination or cross-talk between synthesis and degradation.     

Racializing teenage pregnancy: 'culture' and 'tradition' in the South African scientific literature

The signifiers, 'race', 'culture' or 'ethnicity' are utilized in the teenage pregnancy literature (1) to highlight 'differences' in adolescent sexual and reproductive behaviour and (2) as explanatory tools. When 'white' teenagers are the focus of research, psychological explanations are usually invoked, whereas for 'black' teenagers, explanations are socio-cultural in nature. In this article, we explore how, through a process of racialization, the psychomedical literature on teenage pregnancy in South Africa contributes to the entrenchment of 'race', 'culture' and 'ethnicity' as fixed, 'natural' signifiers. We utilize Derrida's notion of différance , together with Phoenix and Woollett's adaptation - 'normalized absence/pathologized presence' - to indicate how 'black' people are cast as the Other, the pathologized presence which relies on the normalized absent trace, 'whiteness', for definition. We analyse how the notions of 'tradition' and 'culture' are deployed to sanitize or disguise the underlying racializing project. 'Black' is exoticized and rendered strange and thus open to scrutiny, monitoring and intervention. 'Culture' and 'tradition' appeal to the myth of origin, thus providing pseudohistorical explanations which essentialize and naturalize racialized collectivities.     

Comparison of Five Populations of Tylenchulus semipenetrans to Citrus,Poncirus, and their Hybrids

The infectivity of five populations of Tylenchulus semipenetrans were compared and differentiated on 10 hosts (5 Citrus spp., 1 Poncirus trifoliata, and 4 hybrids of Citrus spp. X P. trifoliata). Differences in levels of infection and development (P = 0.01) occurred between Citrus spp. and P. trifoliata cv. ''Pomeroy'' and their three hybrids, C. paradisi X P. trifoliata cv. ''Swingle'' citruntelo and C. sinensis, cv. ''Ruby'' orange X P. trifoliata cv. ''Webber Fawcett 14-7'', and ''15-7''. Poncirus trifoliata cv. Pomeroy was susceptible to a California biotype 3 and highly resistant to the other citrus nematode populations. Low infection levels with California biotype 1, Arizona, and Florida populations on Swingle citrumelo, and the two Ruby orange hybrids indicated inherited resistance. Reproduction of the nematode population from Texas was greatest on the three hybrids, Swingle citrumelo, Ruby orange 14-7, and 15-7, from the California 1, Arizona, and Florida populations, but its comparable densities on P. trifoliata and Citrus spp. were not sufficiently different from these populations to consider it a separate biotype. California biotype 3 was sufficiently different from all other populations to be considered a different biotype, and it was named the "Poncirus biotype."     

Impact of Plant Nutrition on Pratylenchus penetrans Infection of Prunus avium Rootstocks

A hypothesis that cherry rootstocks grown under optimal nutrient conditions are affected less by Pratylenchus penetrans infection than those grown under deficient nutrient conditions was tested by growing four Prunus avium L. rootstocks (''Mazzard'', ''Mahaleb'', ''GI148-1'', and ''GI148-8'') at a soil pH of 7.0 over a period of 3 months under greenhouse conditions (25 ñ 2 °C). Pratylenchus penetrans was inoculated at 0 (control) or 1,500 nematodes per g fresh root weight for a total of 3,600, 4,200, 10,500, and 11,400 per plant on Mazzard, Mahaleb, GI148-1, and GI148-8, respectively, with nutrients (commercial fertilizer) applied once at planting (deficient) or twice weekly (optimal). The experiment was repeated once. The optimum nutrient regime resulted in greater soil nutrient levels and plant growth; higher leaf concentrations of N, P, K, and Mg; and fewer P. penetrans than under the deficient nutrient regime. The addition of fertilizer either may increase nematode mortality in the soil or improve rootstock resistance to nematode infection. Increases in Ca in leaves from the nutrient-deficient and nematode-infected treatments suggested the plants were physiologically stressed. The Pf/Pi ratios indicated that these rootstocks may have had resistance to P. penetrans; however, because of the dominant role of nutrition in the experimental design, the question of resistance could not be properly addressed.     

Developmental forms of human skeletal-muscle AMP deaminase. The kinetic and regulatory properties of the enzyme.

AMP deaminase isoforms from human skeletal muscle can be separated chromatographically [Kaletha, Spychała & Nowak (1987) Experientia 43, 440-443]. In adult tissue nearly all the AMP deaminase activity was eluted from phosphocellulose with 0.75 M-KCl (''adult'' isoform), and the remaining activity could be eluted with 2.0 M-KCl. Conversely, most of the AMP deaminase activity from 11-week-old fetal tissue was eluted from phosphocellulose with 2.0 M-KCl (''fetal'' isoform). In the present paper the kinetic and regulatory properties of AMP deaminase extracted from 11- and 16-week-old fetal skeletal muscle are reported. The two isoforms from 11-week-old human fetus differed distinctly in these properties. The ''fetal'' isoform had about 5-fold higher half-saturation constant (S0.5) value than the ''adult'' form. It was also more sensitive to the influence of some important regulatory ligands (ADP, ATP and Pi), and exhibited a different pH/activity profile. The ''adult'' isoform of AMP deaminase from fetal muscle and the enzyme from mature muscle possessed similar kinetic and regulatory properties. This isoform seems not to be subject to any major modifications during further ontogenesis. This is not true, however, for the ''fetal'' isoform. In the muscle of 16-week-old human fetus, the ''fetal'' isoform showed a peculiar, biphasic, type of substrate-saturation kinetics. This phenomenon may reflect appearance of the next, developmentally programmed, isoform of human skeletal-muscle AMP deaminase.     

Presence of allotypic determinants on polypeptide subunits of rabbit gamma globulin

Inhibition of passive haemagglutination showed the presence of the allotypic specificities Aa1 Aa2, Aa3, Ab4, Ab5 and Ab6 on polypeptide subunits of rabbit IgG belonging to the phenotypes Aa1-3/Ab4-4 Aa2-2/Ab4-4, Aa3-3/Ab4-4, Aa3-3/Ab4-5 and Aa3-3/Ab4-6, prepared by oxidative sulphitolysis followed by isolation on Sephadex G-100 in 6m urea and 0.05m formic acid. The determinants Aa1, Aa2 and Aa3 were found only on H chains and Ab4, Ab5 and Ab6 only on L chains. Of the latter, Ab4 and Ab5 were found in both fractions, i.e. L₁ and L₂, of the light chains, while Ab6 was found only in fraction L₁.     

Live Imaging of Apoptotic Cell Clearance during Drosophila Embryogenesis

The proper elimination of unwanted or aberrant cells through apoptosis and subsequent phagocytosis (apoptotic cell clearance) is crucial for normal development in all metazoan organisms. Apoptotic cell clearance is a highly dynamic process intimately associated with cell death; unengulfed apoptotic cells are barely seen in vivo under normal conditions. In order to understand the different steps of apoptotic cell clearance and to compare ''professional'' phagocytes - macrophages and dendritic cells to ''non-professional'' - tissue-resident neighboring cells, in vivo live imaging of the process is extremely valuable. Here we describe a protocol for studying apoptotic cell clearance in live Drosophila embryos. To follow the dynamics of different steps in phagocytosis we use specific markers for apoptotic cells and phagocytes. In addition, we can monitor two phagocyte systems in parallel: ''professional'' macrophages and ''semi-professional'' glia in the developing central nervous system (CNS). The method described here employs the Drosophila embryo as an excellent model for real time studies of apoptotic cell clearance.     

Effects of Temperature on Development of Heterodera glycines on Glycine max and Phaseolus vulgaris

Soybean cyst nematode resistant ''Fayette'' and susceptible ''Williams 79'' soybeans (Glycine max) and resistant ''WIS (RRR) 36'' and susceptible ''Eagle'' snap beans (Phaseolus vulgaris) were used in determining the effects of host and temperature on the development, female production, sex ratios, and host response to Heterodera glycines. Temperatures were maintained constant at 16, 20, 24, 28, and 32 C using water-filled tanks. The most rapid development and greatest female production occurred between 20 and 28 C. The equation DS = 5(10⁻⁶)x²y² - 3(10⁻⁴)x²y - 2.8(10⁻³)x² - 1.94(10⁻²)y² + 0.4288x + 1.0220y - 12.7185, where DS = developmental stage, X = time, and Y = temperature, predicted the developmental stage of the nematode and accounted for 84% of the variation. Male : female ratios did not differ within this range and were generally less than one. At all temperatures the resistant soybean produced the greatest number of necrotic responses to H. glycines infection, followed by the resistant snap bean. The susceptible soybean and snap bean produced the fewest necrotic responses.