Phase diagram of stigmasterol-dipalmitoylphosphatidylcholine mixtures dispersed in excess water

As a simple model of rafts in plant cells, the effect of stigmasterol, one of the predominant sterols in plant plasma membranes, on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multilayers has been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and freeze-fracture electron microscopy (FFEM) techniques. A partial phase diagram of the binary system has been constructed. Particularly, the stigmasterol concentrations of the “left endpoint” and “right endpoint” of the three-phase line have been determined using the newly developed linear and nonlinear fitting method. They are 6.2 and 23.7 mol%, respectively. Furthermore, the resemblance and difference of phase diagrams of DPPC/stigmasterol, DPPC/cholesterol, and DPPC/ergosterol have been compared and the efficiency of these sterols in promoting the formation of the liquid-ordered domains (rafts) have also been discussed.     

Biosynthesis of 3,4-dihydroxyphenylalanine in Vicia faba

Radioactive shikimic acid and l-tyrosine were shown to be efficient precursors of 3,4-dihydroxyphenylalanine (DOPA) in Vicia faba. [1-¹⁴C]Acetate and l[U-¹⁴C]phenylalanine were not incorporated into tyrosine or DOPA. Thus the synthesis of DOPA occurs via the shikimic acid pathway and tyrosine or a very closely related metabolise. Phenolase was present in etiolated plants in much larger quantities after a brief light exposure whereas DOPA concentration was relatively constant during all stages of plant growth. Partially purified phenolase did not catalyze the conversion of tyrosine to DOPA and does not appear to have a role in DOPA synthesis.     

ZBTB38 gene polymorphism associated with body measurement traits in native Chinese cattle breeds

Body measurement traits, influenced by genes and environmental factors, play numerous important roles in the value assessment of productivity and economy. In this study, we investigated the association between genetic polymorphisms of the zinc finger and BTB domain containing 38 gene (ZBTB38) and body measurement traits in native Chinese cattle. Using direct DNA sequencing in 423 individuals of 8 different cattle subpopulations, 9 novel polymorphisms were identified for genotyping within 647 bp region of exon 1 of ZBTB38. Linkage disequilibrium and association analysis revealed that two coding exon polymorphisms (2323 G>A and 2325 C>T polymorphisms), missense mutations valine GTC(T) to isoleucine ATC(T), were associated with body length (BL), withers height (WH) and rump length (RL). Furthermore, the analysis of 2323 G>A and 2325 C>T SNP markers shows that there are significant effects on the BL (P = 0.0488), WH (P = 0.0044) and RL (P = 0.0314) in the total population. These results clearly suggest that the ZBTB38 gene is among the target genes for body measurement traits in bovine breeding, and provide data for establishment of an animal model using cattle to study big animal body type.     

Host status of some broad bean,Vicia faba L., selections to reniform nematode,Rotylenchulus reniformis,under greenhouse conditions in Egypt

Twenty broad bean selections were screened for their relative susceptibility to the reniform nematode, Rotylenchulus reniformis, under greenhouse conditions at 20?±?5?°C. The degree of susceptibility was rated based on number of females per root system of each selection. Hence, G 3, L 47, L 49, L 52, L 57, L 71, L 92, L 99 and L 375 selections were graded as resistant hosts against the nematode infection and sex selections (G 429, L 13, L 16, L 24, L 31 and L 46) were categorised as moderately resistant. However, only the selection L 9 out of 20 selections was ranked as susceptible and four selections, namely L 50, L 101, L 241 and L 348, were rated as highly susceptible against R. reniformis infection. It was observed that reproduction of the nematode was favoured on highly susceptible and susceptible selections but inhibited on resistant ones. Therefore, all tested selections showed great variability in their reaction to the nematode infection according to the host type. Also, various plant growth parameters were discussed. Finally, the differences among the tested selections should serve as an informative resource for plant breeders and cropping systems to limit the loss due to the nematode infection.     

Influence of certain agricultural practices on the cowpea aphid,Aphis craccivora Koch,infesting broad bean crops and the relation between the infestation and yield of plants in upper Egypt

Abstract

The effect of certain agriculture practices such as susceptibility of six broad bean varieties, space of planting, nitrogen fertilization levels, first irrigation and farmyard manure on the infestation of broad bean crop with the Aphis craccivora Koch was studied at El-Kawsar region, Sohag Governorate (about 495 km south of Cairo, Egypt) throughout the 2003/2004 and 2004/2005 seasons. The results obtained revealed that A. craccivora appeared from November until the second week of April. Also, the faba bean varieties were different in their susceptibility to the infestation with A. craccivora, dividing into three groups: the first one which was susceptible included Giza 674 and Giza Blanka; the second had low resistance and included Giza 843, Giza 2 and Giza 40; and the third group was moderate including Giza 429. The numbers of A. craccivora was significantly increased at 70 kg chemical nitrogen plus farmyard manure than at 40 or 55 units/feddan of chemical nitrogen during the two seasons. The population density of A. craccivora was significantly higher when decreasing the planting space. The population density of A. craccivora increased significantly with an increase of nitrogen fertilization levels during both seasons. The broad bean plants sown on 10 cm and which received N at a rate of 90 kg/fed. harboured the highest numbers of A. craccivora as compared with the other treatment (20 and 30 cm). The results show also that the broad bean plants which were irrigated at 56 and 63 days as a first irrigation harboured highly significant numbers of A. craccivora compared with the plants irrigated at 14, 21 and 28 days. These results also show significant negative correlation between the infestation of A. craccivora and the yield of broad bean plants.     

Exogenous application of liquid diet,previously fed upon by pea aphids Acyrthosiphon pisum (Harris), to broad bean leaves induces volatiles attractive to the specialist parasitic wasp Aphidius ervi (Haliday)

Proof of the existence of aphid-derived molecules that induce emission of volatile organic compounds as indirect defensive responses in plants (hereafter called elicitors) has not yet been obtained. We showed here the presence and some aspects of the chemical nature of these elicitors. Exogenous application of the fed diet (liquid diet previously fed on by the Pea aphid, Acyrthosiphon pisum) on the damaged part of leaves of broad bean plants, made the plants more attractive to a parasitic wasp, Aphidius ervi, than application of the unfed diet. This result suggested that elicitors existed in the fed diet. Chemical characterization using ultrafiltration and subsequent bioassay revealed that the responsible factor was larger than 3 kDa. Heating of the fed diet did not inactivate its ability to induce attractive volatiles, which suggested thermotolerance of the elicitor. These results contribute to the mechanistic understanding of plant defenses against aphids.     

Philip Miller and the plants from the Chelsea Physic Garden presented to the Royal Society of London, 1723–1796

Summary

From 1723 to 1796 the Society of Apothecaries of London presented annually to the Royal Society of London 50 dried specimens of plants grown the previous year in the Chelsea Physic Garden, this being a condition of Sir Hans Sloane's deed of gift of the Garden to the Apothecaries in 1722. These herbarium specimens are now in the Department of Botany, British Museum (Natural History), London. Many represent plants recorded in successive editions of Philip Miller's Gardeners Dictionary and, together with Miller's own specimens also in the British Museum (Natural History) and Ehret's drawings, may serve to typify binomials published in the 8th edition (1768) of his Dictionary. They were listed from 1723 to 1774 in the Philosophical Transactions of the Royal Society; the lists here contain six long-overlooked binomials Galium verrucosum Huds. (syn. G. valantia Weber), Gypsophila pilosa Huds. (syn. G. porrigens (L.) Boiss), Briza pinnata Huds. (= Demazeria sicula (Jacq.) Dumort.) Euphorbia hispanica Huds. (= E. esula var. lanceolata Gren. & Godron), Pteris cheusanica Curtis (= P. ensiformis Burm. f.) and Saxifraga stolonifera Curtis (syn. S. sarmentosa L.). The deed of conveyance is printed as an appendix.     

Festuca rohlenae (Poaceae): A neglected taxon of the Montenegro

Abstract

Festuca porcii var. angustifolia is raised to the rank of a species under the new name F. rohlenae. It is an endemic of SE Dinarides in Montenegro, and it is most similar to the Carpathian F. porcii. Both species have the “broad‐leaved syndrome” and exhibit an intermediacy between “fine‐leaved” and “broad‐leaved” fescues. The comparative morpho‐anatomical data and the distribution map as well as basic ecological information of F. rohlenae are herewith presented.     

沈抚灌区广宿主石油烃代谢质粒的分离及鉴定

本研究采用“三亲配对外源分离法”,从沈抚灌区土壤、底泥和水样中共计分离得到8个广宿主（BHR）石油烃代谢质粒,并通过对其进行抗生素抗性检测和抗性遗传标记,将其转移至大肠杆菌(Escherichia coli)EC100宿主中进行操作.不相容性群分析结果表明: pS3-2C、pS4-6G为Inc P质粒;pS3-2G、pW22-3G、pA15-7G为Inc N质粒;pS7-2G 为Inc W质粒;pA23-1G和 pA10-1C为Inc Q质粒.采用PCR扩增已报道的石油烃污染物降解基因的方法初步分析其石油烃代谢功能,质粒pS3-2G、pS7-2G、pA23-1G、pW22-3G和pA10-1C上含有编码芳香环羟化双加氧酶基因(phdA)和甲苯单加氧酶基因(touA)的片段;pA15-7G含有编码甲苯双加氧酶和甲苯单加氧酶基因片段;pS3-2C含有编码芳香环羟化双加氧酶、苯双加氧酶和甲苯双加氧酶基因片段;pS4-6G仅含有编码芳香环羟化双加氧酶基因片段.通过宿主范围检测,除质粒pS3-2C外,其余7个质粒均可在变形菌纲(Proteobacteria)α-、β-、γ-亚纲的代表性菌株根瘤农杆菌(Agrobacterium tumefaciens)C58、钩虫贪铜菌(Cupriavidus necator)JMP228、大肠杆菌EC100间进行转移并稳定传代.     

A comparative calorimetric study of the effects of cholesterol and the plant sterols campesterol and brassicasterol on the thermotropic phase behavior of dipalmitoylphosphatidylcholine bilayer membranes

We present a comparative differential scanning calorimetric study of the effects of the animal sterol cholesterol (Chol) and the plant sterols campesterol (Camp) and brassicasterol (Bras) on the thermotropic phase behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers. Camp and Bras differ from Chol in having a C24 methyl group and, additionally for Bras, a C22 trans-double bond. Camp and especially Bras decrease the temperature, cooperativity and enthalpy of the DPPC pretransition more than Chol, although these effects are attenuated at higher sterol levels. This indicates that they destabilize gel-state DPPC bilayers to a greater extent, but are less soluble, than Chol. Not surprisingly, all three sterols have similar effects on the sterol-poor sharp component of the DPPC main phase transition. However, Camp and especially Bras less effectively increase the temperature and decrease the cooperativity and enthalpy of the broad component of the main transition than Chol. This indicates that at higher sterol concentrations, Camp and Bras are less miscible and less effective than Chol at ordering the hydrocarbon chains of the sterol-enriched fluid DPPC bilayers. Overall, these alkyl side chain modifications generally reduce the ability of Chol to produce its characteristic effects on DPPC bilayer physical properties. These differences are likely due to the less extended and more bent conformations of the alkyl side chains of Camp and Bras, producing sterols with a greater effective cross-sectional area and reduced length than Chol. Hence, the structure of Chol is likely optimized for maximum solubility in, as opposed to maximum ordering of, phospholipid bilayers.