Flagellar structure in spermatids of several species of cricket was studied with the electron microscope. The flagella of mid-spermatids contain the usual 9 + 2 set of fibers and a set of nine accessory fibers. At first all are hollow, then the lumina become filled with an electron-opaque matrix material in which narrow electron-lucent microcylinders are embedded. The accessory fibers and one c...

microtubules are unique cytoskeletal structures that have structural subunits of αβ tubulin. taxol is a typical microtubule stabilizing drug. the epothilones are other natural products with similar mechanism of action totaxol. despite the highly conserved nature of β-tubulin, some organism like saccharomyces cerevesia is resistance to taxol, but sensitive to epothilones. in order to find differ...

We present in this paper a new strategy of handwriting or hand drawing velocity modeling Based on the Beta theory. The introduced approach aims to improve the interpretability of the dynamic profile model, reduce the data redundancy, and ameliorate the features accuracy. Indeed, we showed that the curvilinear velocity of handwritten or hand drawn trajectory can be rebuilt by superposing two com...

Designing a building or a new urban space is collaborative work that involves several people with different backgrounds. To achieve consensus all participants in the process meet to discuss documents such as floor plans and sections. This paper reports on the progress of Space Pen, a new system to allow several users to draw on and annotate a three-dimensional representation of a building remot...

Microtubules are constituents of axonemes, mitotic spindles, and elaborate arrays in interphase cells, and, with intermediate filaments and microfilaments, are among the most prevalent structures visualized in the cytomatrix (22, 44). With the exception ofthe A microtubule ofcilia and flagella, the lattice geometry ofmicrotubules is highly conserved . However, each of the major subunits of micr...

objective: to study the structure and distribution of microtubules in embryos derived from young, old and reconstructed oocytes. materials and methods: embryos obtained from old (50 embryos), young (50 embryos) and reconstructed oocytes (10 embryos) were studied by immunocytochemistry. the microtubule structures of the embryos were studied by using fluroscent microscopy with fitc-pi filter and ...

Megakaryocytes from guinea pig bone marrow were isolated and maintained in liquid culture and were treated with ADP, thrombin, arachidonic acid, or collagen. Megakaryocytes spread with an active ruffled membrane in response to ADP (1-100 microM), thrombin (1.0 U/ml), and arachidonic acid (50 microM) but responded to collagen surfaces only if fibronectin was added to the cultures. Spreading coul...

Liquid-liquid phase separation occurs not only in bulk liquid, but also on surfaces. In physiology, the nature and function of condensates cellular structures is just beginning to be explored. Here, we study how condensed protein TPX2 behaves microtubules initiate branching microtubule nucleation, process by which nucleate off sides preexisting microtubules. This autocatalytic nucleation pathwa...

Wnt ؉ BMP ‫؍‬ stem cell tem cell fate is determined by growth factors. But on page 309, Kléber et al. show that the right combination of growth factors can also keep cells from committing to a differentiated fate. Neural crest stem cells (NCSCs), they find, are maintained by the dual punch of Wnt and BMP. NCSCs have the potential to become many different cell types. For example, Wnt exposure of...