The Pex16p homolog SSE1 and storage organelle formation in Arabidopsis seeds

Mature Arabidopsis seeds are enriched in storage proteins and lipids, but lack starch. In the shrunken seed 1 (sse1) mutant, however, starch is favored over proteins and lipids as the major storage compound. SSE1 has 26 percent identity with Pex16p in Yarrowia lipolytica and complements pex16 mutants defective in the formation of peroxisomes and the transportation of plasma membrane- and cell wall-associated proteins. In Arabidopsis maturing seeds, SSE1 is required for protein and oil body biogenesis, both of which are endoplasmic reticulum-dependent. Starch accumulation in sse1 suggests that starch formation is a default storage deposition pathway.     

Volcanic activity and climatic changes

Radiocarbon dates of volcanic activity suggest variations that appear to be related to climatic changes. Historical eruption records also show variations on the scale of years to centuries. These records can be combined with simple climatic models to estimate the impact of various volcanic activity levels. From this analysis it appears that climatic prediction in the range of 2 years to many decades requires broad-scale volcanic activity prediction. Statistical analysis of the volcanic record suggests that some predictability is possible.     

Oral biology and conditions of amphibians.

This article reviews the anatomy of the skull and oral cavity in the three amphibian orders. Feeding behavior and feeding physiology are also described. A review is given of reported oral pathology. The pathology is divided into infectious causes (bacterial and parasitic) and noninfectious causes (trauma, neoplasia, and nutritional).     

Electrophoretic and serological comparisons of pathogenesis-related (b) proteins from different plant species

Preparations of pathogenesis-related (b) proteins (PRs) from differentNicotiana species, tomato,Gynura aurantiaca, bean, and cowpea were compared to each other and to bean chitinase and a constitutive apple agglutinin by electrophoresis in polyacrylamide gels both in the absence and in the presence of SDS, and by serological double diffusion analysis using antisera against tobacco PRs and bean chitinase. PRs from different plant genera displayed a similar but not identical range of relative mobilities in both native and SDS gels, whereas bean chitinase and apple agglutinin were clearly different. None of the antisera reacted with any of the PR preparations from plant genera other than the one from which the antigen(s) had been derived. Whilst PRs within the genusNicotiana are serologically related and can be identical, PRs from different plant genera seem to be sufficiently different to be considered as genus-specific.     

Duration of the persistent activity of moxidectin against Haemonchus contortus in sheep

SUMMARY Weaned lambs were infected with Haemonchus contortus 35,28,21,14 and 7 days after treatment with moxidectin at 0.2 mg/kg and 35 and 14 days after treatment with ivermectin at the same dose rate. Worm counts 14 days after infection showed that moxidectin prevented the establishment of over 99% of infective larvae for 28 days and reduced the establishment rate at 35 days by 96%, relative to ivermectin. There was no difference in the protective efficacy of ivermectin at 14 or 35 days. The persistence of moxidectin is likely to provide advantages in nematode control, particularly when used as a strategic early summer treatment or as a pre-lambing treatment to ewes. Implications of the persistent activity of moxidectin for the development of resistance during the decay phase are discussed.     

转铁蛋白受体上的犬细小病毒壳体结合位点及其亲和力改变对细胞吸收和感染的影响

犬细小病毒及其相近的猫泛白细胞减少征病毒与转铁蛋白受体(TfR)1型结合后而感染宿主细胞,但研究显示犬猫TfRs的不同使病毒的宿主范围和组织嗜性也有所不同。通过点突变及增加或减少糖基化信号改变顶端及类蛋白酶区域残基,然后检测这些突变的TfR与壳体的相互作用,发现大多数的置换体对病毒的结合和摄取几乎没有影响,但在受体顶端区域的一些位点突变可以阻止壳体的结合或在不同程度上降低受体的亲和力。顶端区域的病毒结合面内的多糖同样可以控制壳体的结合。犬细小病毒可用含有犬TfRs特异性的糖基化受体从而介导有效的感染,与之相关的猫泛白细胞减少征病毒却不能。另外,添加一个N-糖基化位点到猫转铁蛋白受体顶端区域的病毒结合面会减少或消除结合和感染。最关键的是,猫转铁蛋白受体第221位残基被任何氨基酸替代都会影响结合和感染,这与被替代残基的生化特性有显著联系。亲和力降低的受体介导感染的能力会发生相应改变。对TfRs突变体在细胞内的结合和摄取形式进行测定,结果显示低亲和力TfRs结合更少的壳体,并且它们吸附于细胞表面和伪足的方式有所不同,但转移至核周包涵体的过程是相似的。