Evolution of asexual and sexual reproduction in the aspergilli.

has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus , and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from , and certain longstanding evolutionary theories have been questioned.

Catatonia in Neurologic and Psychiatric Patients at a Tertiary Neurological Center.

This study describes the prevalence, phenomenology, treatment, and outcome of neurological patients and psychiatric patients with catatonia at a tertiary neurological center. Clinical variables included nosological diagnoses and complications. Admission length and days with catatonia were used as outcome measures.

Transformation of taxol-stabilized microtubules into inverted tubulin tubules triggered by a tubulin conformation switch.

Bundles of taxol-stabilized microtubules (MTs)--hollow tubules comprised of assembled αβ-tubulin heterodimers--spontaneously assemble above a critical concentration of tetravalent spermine and are stable over long times at room temperature. Here we report that at concentrations of spermine several-fold higher the MT bundles (B(MT)) quickly become unstable and undergo a shape transformation to bundles of inverted tubulin tubules (B(ITT)), the outside surface of which corresponds to the inner surface of the B(MT) tubules. Using transmission electron microscopy and synchrotron small-angle X-ray scattering, we quantitatively determined both the nature of the B(MT)-to-B(ITT) transformation pathway, which results from a spermine-triggered conformation switch from straight to curved in the constituent taxol-stabilized tubulin oligomers, and the structure of the B(ITT) phase, which is formed of tubules of helical tubulin oligomers.

Ion specific effects in bundling and depolymerization of taxol-stabilized microtubules.

Microtubules (MTs) are nanometer scale hollow cylindrical biological polyelectrolytes. They are assembled from alpha/beta-tubulin dimers, which stack to form protofilaments (PFs) with lateral interactions between PFs resulting in the curved MT. In cells, MTs and their assemblies are critical components in a range of functions from providing tracks for the transport of cargo to forming the spindle structure during mitosis.

Hydrodynamic interactions between colloidal particles in a planar pore.

The correlation between the motion of pairs of colloidal particles confined in a planar pore is measured using optical microscopy. The systems studied here are aqueous suspensions of polystyrene spheres of diameter 1.9 μm, interacting as effective hard spheres, confined between two parallel planar plates separated by 2.