安哥拉山羊及其杂种羊父权认定的DNA指纹图分析

应用ＤＮＡ指纹技术对安哥拉山羊作亲子鉴定,结果发现子代个体的ＤＮＡ指纹图中,谱带均分别来自父亲和母亲,没有新带出现。父权概率为０．９８８９,表明（ＣＡ／ＧＡＴＡ／ＴＣＣ）５探针能有效地应用于安哥拉山羊及其杂种后代的遗传分析。     

The state of the Universe

The past 20 years have seen dramatic advances in cosmology, mostly driven by observations from new telescopes and detectors. These instruments have allowed astronomers to map out the large-scale structure of the Universe and probe the very early stages of its evolution. We seem to have established the basic parameters describing the behaviour of our expanding Universe, thereby putting cosmology on a firm empirical footing. But the emerging 'standard' model leaves many details of galaxy formation still to be worked out, and new ideas are emerging that challenge the theoretical framework on which the structure of the Big Bang is based. There is still a great deal left to explore in cosmology.     

Emergence of a techno-legal specialty: Animal tests to assess chemical safety in the UK, 1945–1960

It has been suggested that knowledge domains which emerge within regulatory science represent a compromise between technical knowledge and policy priorities. This article investigates the claim through consideration of the emergence of animal tests to evaluate chemical safety in the UK between 1945 and 1960. During this period there was a proliferation of new chemical-based innovations in consumer products. The situation gave rise to concerns about the potential impact on public health. Solutions required development of a knowledge domain that would fulfil policy requirements, outside the remit of academic science. Lack of consensus in the scientific field gave rise to debate over the best means to collect accurate data. This resulted in emergence of the new specialty of safety testing, in response to political and industrial needs. The socio-political context of this case illustrates the impact that organisational setting can have on shaping knowledge claims.     

Intracellular pH of Limulus ventral photoreceptor measured with a double-barrelled pH microelectrode

Summary The intracellular pH of the Limulus ventral photoreceptor was measured with a double-barrelled pH microelectrode and found to be 7.01±0.04 SE (n=9).This work was supported by the Swiss National Science Foundation, grants Nos. 3.634.075 and 3.128.73.Acknowledgments. We thank Drs L. R. Pucacco and N. W. Carter for technical advice and a gift of pH glass. We also thank Drs M. Tsacopoulos and F. Baumann for helpful discussion.     

Oxygen uptake occurs faster than sodium pumping in bee retina after a light flash

When neurones are active there is an entry of Na+, which must subsequently be pumped out, and an increase in their oxygen consumption rate (Qo2). The Na+ pump derives its energy from ATP, splitting it into ADP and Pi, and it has reasonably been proposed that the changes in concentrations of ATP, ADP and Pi lead to a stimulation of the O2 consumption by the mitochondria and hence to a restoration of the stock of ATP. Here we present evidence suggesting that Qo2 must be controlled differently in the retinal photoreceptor cells of the honeybee drone. Stimulation of drone photoreceptors with a flash of light causes an entry of Na+ (ref. 4) and a transient increase in Qo2 that indicates respiration of the right order of magnitude to provide ATP to pump the Na+ out. We report intracellular recordings of changes in intracellular sodium (Nai+) and potassium (Ki+) in response to single light flashes and have compared the time course of extra oxygen consumption (delta Qo2) with these ion changes and other indices of Na+ pumping. We found that the time course of pumping seems to lag behind the time course of delta Qo2. It follows that the mitochondrial respiration must be stimulated by some signal which is generated earlier than the rise in ADP produced by the Na+ pump.     

Tyrosine kinase receptor RET is a key regulator of Peyer's patch organogenesis

Normal organogenesis requires co-ordinate development and interaction of multiple cell types, and is seemingly governed by tissue specific factors. Lymphoid organogenesis during embryonic life is dependent on molecules the temporal expression of which is tightly regulated. During this process, haematopoietic 'inducer' cells interact with stromal 'organizer' cells, giving rise to the lymphoid organ primordia. Here we show that the haematopoietic cells in the gut exhibit a random pattern of motility before aggregation into the primordia of Peyer's patches, a major component of the gut-associated lymphoid tissue. We further show that a CD45+CD4-CD3-Il7Ralpha-c-Kit+CD11c+ haematopoietic population expressing lymphotoxin has an important role in the formation of Peyer's patches. A subset of these cells expresses the receptor tyrosine kinase RET, which is essential for mammalian enteric nervous system formation. We demonstrate that RET signalling is also crucial for Peyer's patch formation. Functional genetic analysis revealed that Gfra3-deficiency results in impairment of Peyer's patch development, suggesting that the signalling axis RET/GFRalpha3/ARTN is involved in this process. To support this hypothesis, we show that the RET ligand ARTN is a strong attractant of gut haematopoietic cells, inducing the formation of ectopic Peyer's patch-like structures. Our work strongly suggests that the RET signalling pathway, by regulating the development of both the nervous and lymphoid system in the gut, has a key role in the molecular mechanisms that orchestrate intestine organogenesis.     

A Kind of Systems Methodology——The SPIPRO Principle

This paper deals with the Self-Increasing-Difficulty system (SIDIS) separated from general systems, with emphasis on the relevant methodology based on the Spiral Combining Propulsion Principle (SPIPRO principle in short). The system feature and its causative factors are analysed, and the implications and mechanism of the SPIPRO principle are discussed. Finally, the application possibilities of this methodology are illustrated with some examples.