Poverty and Health Ethics in Developing Countries

Developing countries face difficulties of exploitation, dehumanisation and lack of ethical professionalism, to an extent that developed countries do not encounter. Poverty-related difficulties include lack of infrastructure, unreasonable dominance of defence-related expenses in the budget, lack of a sufficient number of health care providers, absence of accountability for serious medical malpractice, as well as exploitation of patients in pharmaceutical trials. This country report presents the case of Bangladesh, one of the poorest countries in the world and therefore a good example for the deplorable condition of the health sector in developing countries.     

Maternal Gametophyte Effects on Seed Development in Maize

Flowering plants, like placental mammals, have an extensive maternal contribution toward progeny development. Plants are distinguished from animals by a genetically active haploid phase of growth and development between meiosis and fertilization, called the gametophyte. Flowering plants are further distinguished by the process of double fertilization that produces sister progeny, the endosperm and the embryo, of the seed. Because of this, there is substantial gene expression in the female gametophyte that contributes to the regulation of growth and development of the seed. A primary function of the endosperm is to provide growth support to its sister embryo. Several mutations in Zea mays subsp. mays have been identified that affect the contribution of the mother gametophyte to the seed. The majority affect both the endosperm and the embryo, although some embryo-specific effects have been observed. Many alter the pattern of expression of a marker for the basal endosperm transfer layer, a tissue that transports nutrients from the mother plant to the developing seed. Many of them cause abnormal development of the female gametophyte prior to fertilization, revealing potential cellular mechanisms of maternal control of seed development. These effects include reduced central cell size, abnormal architecture of the central cell, abnormal numbers and morphology of the antipodal cells, and abnormal egg cell morphology. These mutants provide insight into the logic of seed development, including necessary features of the gametes and supporting cells prior to fertilization, and set up future studies on the mechanisms regulating maternal contributions to the seed.     

Two Additional Phosphorylases in Developing Maize Seeds

Two additional phosphorylases (III and IV) have been detected in developing seeds of maize. Phosphorylase IV is found only in the embryo (with scutellum). It is also present in the embryo of the germinating seed where its activity is 90-fold greater than the activity in the developing embryo 22 days after pollination. Phosphorylase IV is eluted from a DEAE-cellulose column in the same fraction as phosphorylase I of the endosperm, and the 2 enzymes are similar in many respects. Phosphorylase IV is distinguished from phosphorylase I by electrophoretic mobility, by pH optimum, and because its properties are not affected by the shrunken-4 mutation.Phosphorylase III is found both in the endosperms and embryos of developing seeds. Activity for this enzyme is not detected in crude homogenates nor eluates from a DEAE-cellulose column apparently because it complexes with a non-dialyzable, heat-labile inhibitor. High activity is found after protamine sulfate fractionation. Phosphorylase III is bound to protamine sulfate and is then removed by washing with 0.3 m phosphate buffer. Phosphorylase III activity in the endosperm is not detectable 8 days after pollination but is present 12 days after pollination. Phosphorylase III differs from phosphorylases I, II, and IV in several respects-pH optimum, pH-independent ATP inhibition, time of appearance in the endosperm, and because purine and pyrimidine nucleotides are equally inhibitory. In common with phosphorylase II, phosphorylase III apparently does not require a primer to initiate the synthesis of an amylose-like polymer.     

玉米种子发育过程中Dad1基因的表达(英文)

Dad1是一个高度保守的细胞程序性死亡抑制基因。以拟南芥Dad1 (AtDad1) cDNA为模板,利用体外RT-PCR对其进行地高辛标记。以产物反义RNA作探针 (顺义RNA为对照),对Dad1在玉米种子发育过程中的时空表达图谱进行了研究。结果表明Dad1在一些衰老组织如子房壁、珠被(Fig.1, B&C)、成熟的胚乳 (Fig.1, E) 以及脱落的根冠细胞 (Fig.2 A)中表达量均较高,同时在新陈代谢活跃的组织如根尖分生组织细胞 (Fig.2, A&B)、发育的子叶(Fig.2, C&D)、雌性生殖细胞 (Fig.1 C)以及发育的胚乳细胞(Fig.1 C)中表达量也较高。结论:同其它植物中的Dad1同源基因一样,玉米中的Dad1基因在胚胎发育及胚乳PCD等多种发育过程中也可能起重要作用。     

British Aid to Medical Schools in Developing Countries

If the British allocation for overseas aid is increased more generous agreements could be made with host universities and with expatriate staff. It would greatly stimulate overseas service by specialist trainees if the professional colleges and the universities agreed that they would be willing to substitute in their training programmes a year or two of service in an overseas medical school for one or more of their orthodox appointments. Consideration might be given by the councils for postgraduate education to ways of facilitating service overseas by specialist trainees and young consultants. The suggestion of the Royal Commission for the expansion of departmental staff establishments and training pools requires that the temporary expatriate occupying a supernumerary post is absorbed into the establishment on his return. While this may be done now in individual cases by personal arrangement a national agreement between universities and the N.H.S. would be necessary for these secondments to be made on the large scale commensurate to the need.For other returning young doctors not yet in specialist training schemes an assurance that applications for appointments by those who had worked in developing countries would receive favourable weighting, by both university and N.H.S. selection committees, would be very helpful.     

赤霉素调控玉米种子活力的研究进展

玉米是我国总产与平均单产最高的主要农作物,对于保障国家粮食安全具有举足轻重的作用。种子活力是衡量种子质量和应用价值的关键指标,高活力种子是确保作物高产、稳产的基础。赤霉素是重要的植物生长调节物质,具有解除种子休眠、促进萌发的作用,外源赤霉素的喷施已被广泛应用于农业生产以提高作物产量。目前赤霉素对玉米种子活力的影响研究多侧重于施加外源GA影响种子活力的相关生理指标上,而赤霉素调控玉米种子活力的作用机理尚需深入研究。本文综述了赤霉素的生物合成、信号转导、作用机制以及对玉米和其他作物种子活力影响的研究进展,旨为深入探究GA对于玉米种子活力的调控机制乃至玉米育种实践中高活力玉米新种质的创制提供参考。