Mechanics and Morphology of Silk Drawn from Anesthetized Spiders

 CO₂ and N₂ anesthetized Nephila spiders produced dragline silk with mechanical properties that differed from control silk as a function of time under anesthesia. Silk from CO₂ spiders had a significantly lower breaking strain and breaking energy, significantly higher initial modulus, and marginally lower breaking stress. At the onset of anesthesia the silk diameter became highly variable. During deep anesthesia silk either became thinner or retained cross-section but fibrillated. Received: 26 August 1999 / Accepted in revised form: 22 December 1999     

Molecular organization of excitatory chemical synapses in the mammalian brain

 Chemical synapses are highly specialized cell–cell junctions designed for efficient signaling between nerve cells. Distinct cytoskeletal matrices are assembled at either side of the synaptic junction. The presynaptic cytomatrix at the active zone (CAZ) defines and organizes the site of neurotransmitter release from presynaptic nerve terminals. The postsynaptic density (PSD) tethers neurotransmitter receptors and the postsynaptic signal transduction machinery. Recent progress in the identification and characterization of novel CAZ and PSD components has revealed new insights into the molecular organization and assembly mechanisms of the synaptic neurotransmission apparatus. On the presynaptic side, Bassoon and Piccolo, two related giant proteins, are crucially involved in scaffolding the CAZ. On the postsynaptic side, two families of multi-domain adaptor proteins, the MAGuKs (membrane-associated guanylate kinase homologs) and the ProSAP (proline-rich synapse-associated protein, also termed Shank) family members are thought to be major organizing molecules of the PSD.