The amoeba of a holomorphic function f is, by definition, the image in Rn of the zero locus of f under the simple mapping that takes each coordinate to the logarithm of its modulus. The terminology was introduced in the 1990s by the famous (biologist and) mathematician Israel Gelfand and his coauthors Kapranov and Zelevinsky (GKZ). In this paper we study a natural convex potential function N f ...

The actin-binding protein ABP-120 has been proposed to play a role in cross-linking F-actin filaments during pseudopod formation in motile Dictyostelium amebas. We have tested this hypothesis by analyzing the phenotype of mutant cell lines which do not produce ABP-120. Two different transformation vectors capable of targeted disruption of the ABP-120 gene locus have been constructed using a por...

In 1882, Ilya Mechnikov discovered the phenomenon of phagocytosis when he studied larvae of starfishes that were present on small thorns from a tangerine tree that had been prepared for Christmas. The next morning he found the thorns surrounded by the mobile cells. Knowing that when inflammation occurs in animals that have a blood vascular system leukocytes escape from their blood vessels, it o...

Invasion of human tissues by the parasitic protozoan Entamoeba histolytica is a multistep process involving, as a first step, the recognition of surface molecules on target tissues by the amebas or trophozoites. This initial contact is followed by the release of proteolytic and other activities that lyse target cells and degrade the extracellular matrix. In other parasitic diseases, as well as ...

explain the C-value paradox—the observation that ge-It has now become clear that lateral DNA transfer has nome size does not necessarily correlate with organism played and continues to play a major role in shaping complexity (for example, the human genome is 30 times genomes. Lateral DNA Transfer constitutes a great effort bigger than that of baker's yeast, yet 20 times smaller to put under one...

The caustics of Fourier integral operators are defined as caustics of the corresponding Schwartz kernels (Lagrangian distributions on X × Y). The caustic set Σ(C) of the canonical relation C is characterized as the set of points where the rank of the projection π : C → X × Y is smaller than its maximal value, dim(X × Y) − 1. We derive the L p (Y) → L q (X) estimates on Fourier integral operator...

The 16th problem of Hilbert addresses the determination and the understanding of the possible topological types of smooth real algebraic curves of a given degree in the projective planeRP . This paper is concerned with a local version of this problem: given a germ (C, 0) of real algebraic plane curve singularity, determine the possible topological types of the smoothings of C. A smoothing of C ...

Host invasion by Entamoeba histolytica, the pathogenic agent of amebiasis, can lead to the development of amebic liver abscess (ALA). Due to the difficulty of exploring host and amebic factors involved in the pathogenesis of ALA in humans, most studies have been conducted with animal models (e.g., mice, gerbils, and hamsters). Histopathological findings reveal that the chronic phase of ALA in h...

An axenic culture of Hartmannella culbertsoni obtained from the American Type Culture Collection was used in this study. Amoebas maintained in a trypticase soy broth medium were concentrated, fixed and dehydrated before being transferred drop-wise to round microscope cover classes for critical point drying in liquid CO2. Dried specimens were coated with carbon and palladium-gold and studied wit...

Metazoan embryogenesis is controlled by a limited number of signaling modules that are used repetitively at successive developmental stages. The development of social amoebas shows similar reiterated use of cAMP-mediated signaling. In the model Dictyostelium discoideum, secreted cAMP acting on 4 cAMP receptors (cARs1-4) coordinates cell movement during aggregation and fruiting body formation, a...