Cytochalasin is known to inhibit cytoplasmic streaming rapidly in characean cells without disassembling their actin bundles. Lower cytochalasin concentrations than those needed for streaming inhibition are now shown to disrupt bundle assembly and, over longer periods, assembled bundles. After local wounding, cytochalasin limited bundle regeneration to the production of polygons and straight, di...

The bacterial flagellar hook connects the helical flagellar filament to the rotary motor at its base. Bending flexibility of the hook allows the helical filaments to form a bundle behind the cell body to produce thrust for bacterial motility. The hook protein FlgE shows considerable sequence and structural similarities to the distal rod protein FlgG; however, the hook is supercoiled and flexibl...

A central task in multiagent resource allocation, which provides mechanisms to allocate (bundles of) resources to agents, is to maximize social welfare. We assume resources to be indivisible and nonshareable and agents to express their utilities over bundles of resources, where utilities can be represented in the bundle form, the k-additive form, and as straight-line programs. We study the comp...

Cell division in many eukaryotes is driven by a ring containing actin and myosin. While much is known about the main proteins involved, the precise arrangement of actin filaments within the contractile machinery, and how force is transmitted to the membrane, remains unclear. Here we use cryosectioning and cryofocused ion beam milling to gain access to cryopreserved actomyosin rings in Schizosac...

In this paper we review the concepts of the superalgebra, superderivation and some properties of them. We will define algebraic and differential superderivations on a superalgebra and will prove some theorems about them, Then we consider a superalgebra bundle, that is an algebra bundle which its fibers are superalgebras and then characterize the superderivations of the algebra of sections of th...

We investigate how a straight skeleton can be used to approximate a motorcycle graph. We explain how to construct a planar straight-line graph G such that the straight skeleton of G reveals the motorcycle graph of M , for every given finite set M of motorcycles. An application of our construction is a proof of the Pcompleteness of the construction problem of straight skeletons of planar straigh...

The aim of this paper is to present the derivation and experimental evaluation of a simultaneous method for camera calibration using straight lines. A mathematical model using straight lines was derived to consider both interior and exterior orientation parameters as unknowns. The interior orientation parameters to be estimated are the camera focal length, the coordinates of the principal point...

In this paper, we extend Sasaki metric for tangent bundle of a Riemannian manifold and Sasaki-Mok metric for the frame bundle of a Riemannian manifold [I] to the case of a semi-Riemannian vector bundle over a semi- Riemannian manifold. In fact, if E is a semi-Riemannian vector bundle over a semi-Riemannian manifold M, then by using an arbitrary (linear) connection on E, we can make E, as a...

Let $M$ be an orientable hypersurface in the Euclidean space $R^{2n}$ with induced metric $g$ and $TM$ be its tangent bundle. It is known that the tangent bundle $TM$ has induced metric $overline{g}$ as submanifold of the Euclidean space $R^{4n}$ which is not a natural metric in the sense that the submersion $pi :(TM,overline{g})rightarrow (M,g)$ is not the Riemannian submersion. In this paper...

Microtubule end-binding (EB) proteins influence microtubule dynamic instability, a process that is essential for microtubule reorganisation during apico-basal epithelial differentiation. Here, we establish for the first time that expression of EB2, but not that of EB1, is crucial for initial microtubule reorganisation during apico-basal epithelial differentiation, and that EB2 downregulation pr...