Dynein has four nucleotide binding sites, of which the functional signi¢cance is unknown except for the single catalytic site. To obtain clues to the function of non-catalytic nucleotide binding, we examined the e¡ect of ADP on the in vitro motility of Chlamydomonas inner-arm dynein species 'a'. Upon continuous perfusion with ATP and ADP, microtubules glided on a dynein-coated glass surface with a velocity that gradually increased over a few minutes. The velocity increased faster at higher ADP concentrations. These results suggest that this dynein is activated by nucleotide binding to regulatory site(s) through an extremely slow process. ß 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.
Hericium erinaceus has been recognized as medical mushroom since ancient time, but its scientific evidence for human health has been still uncertain. In this study, we tested a randomized, double-blind, placebo-controlled parallel-group comparative study to evaluate the improvement of the cognitive functions by taking supplements containing fruiting body of H. erinaceus for 12 weeks. We performed three kinds of tests: Mini Mental State Examination (MMSE), Benton visual retention test, and Standard verbal paired-associate learning test (S-PA). MMSE alone showed that oral intake of H. erinaceus significantly improved cognitive functions and prevented from the deterioration. We speculate that various chemical compounds, including hericenones, in the mushroom have multiple effects to the brain neural networks and improve cognitive functions. Oral intake of H. erinaceus is safe and convenient method for dementia prevention so far.
Neutrophils play an essential role in the innate immune response. To understand neutrophil activity, the development of a new technique to observe neutrophils in situ is required. Here, we report the development of a non-invasive technique for the in vivo imaging of neutrophils labeled with quantum dots, up to 100 mm below the skin surface of mice. Upon inflammation neutrophils began to extravasate from blood vessels and locomoted in interstitial space. Most intriguingly, the quantum dots were endocytosed into vesicles in the neutrophils, allowing us to track the vesicles at 12.5 msec/frame with 15-24 nm accuracy. The vesicles containing quantum dots moved as ''diffuse-and-go'' manner and were transported at higher speed than the in vitro velocity of a molecular motor such as kinesin or dynein. This is the first report in which non-invasive techniques have been used to visualize the internal dynamics of neutrophils.N eutrophils are the most abundant type of white blood cell and are important in innate immunity and the acute inflammatory response. Upon inflammation or bacterial invasion, cytokines are produced in the regions surrounding the inflammation. These signals recruit neutrophils to the site of inflammation via their extravasation from blood vessels 1-3 . Despite progress in genetic engineering techniques, experiments with neutrophils have been remained difficult because neutrophils have a short life span and do not grow or differentiate in vitro. Neutrophil-like cell lines have been investigated for cell-based biological studies; however, the motility of these cells is often distinct from that of primary neutrophils in vivo.Previous studies detailing the in vivo imaging of neutrophils have used mice in which the EGFP gene was inserted into the lysozyme M locus, resulting in the specific labeling of neutrophils and macrophages 4 . Twophoton microscopy allowed for the investigation of the collective behaviors of the EGFP-expressing neutrophils in vivo in response to bacterial infection or injury after the dissection of draining lymph nodes 5 or thoracotomy 6 . These observations clearly revealed interactions between neutrophils and macrophages. However, with twophoton microscopy, the fluorophores are excited by only a small number of photons, and the images are captured using single-spot scanning. Therefore, the images of two-photon microscopy are darker than that of spinningdisk confocal microscopy using multi-spot scanning, and longer sampling time is required to collect enough fluorescence photons. Moreover, the fluorescence is strongly scattered and absorbed by the epidermis and cortex. Therefore, surgery is needed to remove the offending tissues and to obtain sufficient fluorescence. However, the surgery itself activates inflammatory signals. Therefore, it has been difficult to maintain non-inflammatory, physiological conditions while performing these types of studies.A wide variety of factors are required for neutrophils to exert their bactericidal function, including various cytokines, proteinases, ...
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