Sexual hormones in Achyla. V. Properties of hormone A of Achyla bisexualis

1. The hormonal coordinating mechanism of the sexual process in Achlya is briefly reviewed. 2. A technique is described for culturing the female plant of Achlya bisexualis in sufficient quantity to furnish material for the chemical study of hormone A. 3. A modification of the biological assay for hormone A is described. 4. Many of the properties of hormone A have been determined: (a) solubilities in common organic solvents, (b) adsorption, (c) stability, (d) inactivation, and (e) reactions with certain reagents. 5. A procedure is described whereby enormous enrichment of the active principle has been achieved

Pathfinding by growth cones in the central nervous system of the grasshopper embryo

Journal ArticleIn the grasshopper embryo the morphological development of individually identified neurons can be traced prior to the onset of axonogenesis on through maturity (eg., Goodman and Spitzer, 1979). The behavior of individual growth cones can be characterized in their natural environment as they extend towards their targets

Guidance of neuronal growth cones: selective fasciculation in the grasshopper embryo

Journal ArticleOne of the central questions of developmental neurobiology concerns how the diversity and specificity of individual neurons are generated during embryonic development. One major component of neuronal diversity is the complex axonal morphology of individual neurons, largely generated early in development and intimately involved in the ability of neurons to find their correct synaptic targets

Schizophyllum commune Bibliography, May 2004

Schizophyllum commune Bibliography, May 200

Why Study Schizophyllum?

For its fascinating sex life, of course! The German mycologist Hans Kniep (1930) was the first to discover that the wood-rotting basidiomycete, Schizophyllum commune, recombines its genome regularly and propagates effectively by consorting with any one of many compatible mates through a system known as tetrapolar sexuality, a term describing the meiotic segregation of four different mating types

Olfactory Sensory Axons Expressing a Dominant–Negative Semaphorin Receptor Enter the CNS Early and Overshoot Their Target

AbstractSensory axons extend from the chick olfactory epithelium to the telencephalon well before the maturation of their target, the olfactory bulb. During a waiting period of several days, olfactory axons arrive and accumulate outside the CNS while the bulb differentiates beneath them. Semephorin-3A is expressed in the telencephalon during this period and has been proposed to prevent their entry into the CNS. We show that the misexpression of a dominant–negative neuropilin-1 that blocks SEMA-3A-mediated signaling in olfactory sensory axons induces many of them to enter the telencephalon prematurely and to overshoot the olfac tory bulb. These results suggest that chemorepellents can prevent the premature innervation of immature targets

Olfactory Sensory Axons Expressing a Dominant–Negative Semaphorin Receptor Enter the CNS Early and Overshoot Their Target

AbstractSensory axons extend from the chick olfactory epithelium to the telencephalon well before the maturation of their target, the olfactory bulb. During a waiting period of several days, olfactory axons arrive and accumulate outside the CNS while the bulb differentiates beneath them. Semephorin-3A is expressed in the telencephalon during this period and has been proposed to prevent their entry into the CNS. We show that the misexpression of a dominant–negative neuropilin-1 that blocks SEMA-3A-mediated signaling in olfactory sensory axons induces many of them to enter the telencephalon prematurely and to overshoot the olfac tory bulb. These results suggest that chemorepellents can prevent the premature innervation of immature targets

Sexual selection in mushroom-forming basidiomycetes

We expect that sexual selection may play an important role in the evolution of mushroom-forming basidiomycete fungi. Although these fungi do not have separate sexes, they do play female and male roles: the acceptance and the donation of a nucleus, respectively. The primary mycelium (monokaryon) of basidiomycete fungi, growing from a germinating sexual spore, is hermaphroditic, but it loses female function upon the acceptance of a second nucleus. The resulting dikaryon with two different nuclei in each cell retains a male potential as both nuclei can fertilize receptive mycelia. We tested the occurrence of sexual selection in the model species of mushroom-forming basidiomycetes, Schizophyllum commune, by pairing monokaryons with fully compatible dikaryons. In most pairings, we found a strong bias for one of the two nuclei although both were compatible with the monokaryon when paired alone. This shows that sexual selection can occur in mushroom-forming basidiomycetes. Since the winning nucleus of a dikaryon occasionally varied depending on the receiving monokaryon, we infer that sexual selection can operate through choosiness of the receiving individual (analogous to female choice). However, in other cases the same nucleus won, irrespective of the receiving monokaryon, suggesting that competition between the two nuclei of the donating mycelium (analogous to male–male competition) might also play a role

Proportion Regulation in Globally Coupled Nonlinear Systems

As a model of proportion regulation in differentiation process of biological system, globally coupled activator-inhibitor systems are studied. Formation and destabilization of one and two cluster state are predicted analytically. Numerical simulations show that the proportion of units of clusters is chosen within a finite range and it is selected depend on the initial condition.Comment: 11 pages (revtex format) and 5 figures (PostScript)

Inducible Germline IgMs Bridge Trypanosome Lytic Factor Assembly and Parasite Recognition

Acknowledgments This work was supported by NSF Bread award IOS-1249166 and Hunter College (J.R.); CUNY Science Scholarship (J.V.); Hunter College HHMI UGRAD Science Education grant 52007535 (E.H.); NIH/NIAID award AI085973 (N.P.); Wellcome Trust award 082786 (J.S.). We thank George Cross and Ana Rodriguez for the parasite lines and VSG preparations used in this study.Peer reviewedPostprin