Changes in progenitor populations and ongoing neurogenesis in the regenerating chick spinal cord

The chick spinal cord can regenerate following injury until advanced developmental stages. It is conceivable that changes in stem/progenitor cell plasticity contribute to the loss of this capacity, which occurs around E13. We investigated the contribution of proliferation, phenotypic changes in radial glia progenitors, and neurogenesis to spinal cord regeneration. There was no early up-regulation of markers of gliogenic radial glia after injury either at E11 or E15. In contrast, increased proliferation in the grey matter and up-regulation of transitin expression following injury at E11, but not E15, suggested high levels of plasticity within the E11 spinal cord progenitor population that are lost by later stages. Changes in neural progenitors with development were also supported by a higher neurosphere forming ability at E11 than at E15. Co-labelling with doublecortin and neuron-specific markers and BrdU in spinal cord sections and dissociated cells showed that neurogenesis is an ongoing process in E11 chick spinal cords. This neurogenesis appeared to be complete by E15. Our findings demonstrate that the regeneration-competent chick spinal cord is less mature and more plastic than previously believed, which may contribute to its favourable response to injury, and suggest a role for neurogenesis in maintaining regenerative capacity.     

The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005–2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores (Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores (Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.     

Negative regulating factors of notch signaling may be a key factor for the teeth root formation

It is still an open question that how the teeth root development is initiated at the molecular level. But what we know is that the teeth root development begins after the crown part is completely formed, and then the terminal cervical loop structure faces two developmental fate options when the crown development is quite advanced: it can remain as a ‘crown’ pattern, and continue enamel production, or it can adopt the ‘root’ fate, and begins teeth root development. Epithelial notch and mesenchymal fgf10 signaling are thought to be the key switches of root or crown development pattern. But, for a rodent's molars and incisors, it is very interesting that after a similar teeth crown developmental process, the late development for the molars and incisors is quite different: the molar germ forms a multi-rooted pattern, while the incisor germ forms a single-rooted analogue and without a really root development process. In a recent study, one of the negative regulating factors for notch signaling, sel1l was found strongly related to the molar root development. So we hypotheses that the negative regulating factors of notch signaling, may be the key signals to determine the tooth root developmental onset, and the quantity or function's abnormal of that factors, may lead to hypoplasia of the teeth root.     

Effects of prey mite species on life history of the phytoseiid predators Typhlodromalus manihoti and Typhlodromalus aripo

The effects of prey mite suitability on several demographic characteristics of phytoseiid predators and the relationship of these effects to the potential of phytoseiid predators to control herbivorous mite populations are well documented. Evidence has also accumulated in the last 20 years demonstrating that phytoseiid predators utilize herbivorous prey mite-induced plant volatiles as olfactory cues in locating their herbivorous mite prey, but less well established is the predictability of reproductive success from the ability of the predators to utilize olfactory cues to locate their prey, and how these processes are related to the success of the predators as biological control agents of the herbivorous mite. In this study, we determined in laboratory no choice experiments, the development, survivorship and fecundity of the two neotropical phytoseiid predators Typhlodromalus manihoti Moraes and T. aripo DeLeon when feeding on three herbivorous mites, including the key prey species Mononychellus tanajoa (Bondar), and the two alternative prey species Oligonychus gossypii (Zacher) and Tetranychus urticae (Koch). Intrinsic rate of increase (r_m) of T. aripo was 2.1 fold higher on M. tanajoa as prey compared with T. urticae as prey, while it was almost nil on O. gossypii. For T. manihoti, r_m was 2.3 fold higher on M. tanajoa as prey compared with O. gossypii as prey, while reproduction was nil on T. urticae. An independent experiment on odor-related prey preference of the two predator species showed that T. manihoti and T. aripo preferred odors from M. tanajoa-infested leaves to odors from O. gossypii-infested leaves. Moreover, both predator species preferred odors from M. tanajoa-infested leaves over those from T. urticae-infested leaves. As reported here, life history of the two predatory mites matches odor-related prey preference if the key prey species is compared to the two inferior prey species. The implications of our findings for the persistence of T. manihoti and T. aripo and biological control of M. tanajoa in the cassava agroecosystem in Africa are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evolutionary morphology and Evo-devo: Hierarchy and novelty

Although the role of morphology in evolutionary theory remains a subject of debate, assessing the contributions of morphological investigation to evolutionary developmental biology (Evo-devo) is a more circumscribed issue of direct relevance to ongoing research. Historical studies of morphologically oriented researchers and the formation of the Modern Synthesis in the Anglo-American context identify a recurring theme: the synthetic theory of evolution did not capture multiple levels of biological organization. When this feature is incorporated into a philosophical framework for explaining the origin of evolutionary innovations and novelties (a core domain of inquiry in Evo-devo) two specific roles for morphology can be described: (1) the conceptualization and operational identification of the targets of explanation; and (2) the elucidation of causal interactions at higher levels of organization during ontogeny and through evolutionary time. These roles are critical components of any adequate explanation of innovation and novelty though not exhaustive of the parts played by morphology in evolutionary investigation. They also invite reflection on what counts as an evolutionary cause in contemporary evolutionary biology.     

从文献统计看我国离子束生物技术的发展

本文检索了1994-2003年间离子束技术在生物领域的应用研究文章,并从文献量,研究材料及研究的水平,期刊,离子源和基金来源等五个方面对其进行了统计和分析。统计结果表明,我国离子束生物技术在国家和地方政府院校的支持下得到了较快发展,其中微生物领域的发展最快;进入21世纪,地方政府院校开始逐渐加大对离子束生物技术的支持,并出现了有企业人员参与研究和企业基金支持的文献;文献内容主要是应用研究,基础研究较为匮乏。在综合分析数据的基础上,展望了我国离子束生物技术的未来发展趋势。     

北京生物技术产业发展研究

生物技术及其相关产业是北京重点发展的高新技术领域之一.“九五”以来北京在该领域取得了稳步发展,具有研发、人才和临床优势.概述了近年来北京生物技术领域在研究、产业、政策等领域的发展现状,提出了目前北京在该领域发展面临的主要问题,并以此为基础为北京市该领域未来发展提出了相关建议.