The Need for Continued Development of Ricin Countermeasures

Ricin toxin, an extremely potent and heat-stable toxin produced from the bean of the ubiquitous Ricinus communis (castor bean plant), has been categorized by the US Centers for Disease Control and Prevention (CDC) as a category B biothreat agent that is moderately easy to disseminate. Ricin has the potential to be used as an agent of biological warfare and bioterrorism. Therefore, there is a critical need for continued development of ricin countermeasures. A safe and effective prophylactic vaccine against ricin that was FDA approved for “at risk” individuals would be an important first step in assuring the availability of medical countermeasures against ricin

Catastrophic disassembly of actin filaments via Mical-mediated oxidation.

Actin filament assembly and disassembly are vital for cell functions. MICAL Redox enzymes are important post-translational effectors of actin that stereo-specifically oxidize actin's M44 and M47 residues to induce cellular F-actin disassembly. Here we show that Mical-oxidized (Mox) actin can undergo extremely fast (84 subunits/s) disassembly, which depends on F-actin's nucleotide-bound state. Using near-atomic resolution cryoEM reconstruction and single filament TIRF microscopy we identify two dynamic and structural states of Mox-actin. Modeling actin's D-loop region based on our 3.9 Å cryoEM reconstruction suggests that oxidation by Mical reorients the side chain of M44 and induces a new intermolecular interaction of actin residue M47 (M47-O-T351). Site-directed mutagenesis reveals that this interaction promotes Mox-actin instability. Moreover, we find that Mical oxidation of actin allows for cofilin-mediated severing even in the presence of inorganic phosphate. Thus, in conjunction with cofilin, Mical oxidation of actin promotes F-actin disassembly independent of the nucleotide-bound state

Cognitive Authority and the Christian Worldview: An Examination of Goodreads Reviews of Christian Books

This study examines how individuals engage with and evaluate Christian books and the cognitive authorities referred to when assessing these resources. 816 book reviews pulled from the reviews for 10 books identified as Christian on the social media book site Goodreads were analyzed by qualitative coding. This content analysis identified themes relating to reader awareness of worldview, evaluative measures used to assess resources, and cognitive authorities referenced. Evaluation of Christian books largely aligns with existing understanding of the general process of information assessment, with a few exceptions.The spiritual nature of the text, for many reviewers, led them to consider the information in light of personal spiritual experience and lent spiritual overtones to their evaluation of the author’s character and expertise. Reviews also demonstrate the way in which individuals can weigh cognitive authorities differently within a shared worldview, resulting in differing information assessments.Master of Science in Information Scienc

The Interaction of Caldesmon with the COOH Terminus of Actin

Caldesmon interacts with the NH2-terminal region of actin. It is now shown in airfuge centrifugation experiments that modification of the penultimate cysteine residue of actin significantly weakens its binding to caldesmon both in the presence and absence of tropomyosin. Furthermore, as revealed by fluorescence measurements, caldesmon increases the exposure of the COOH-terminal region of actin to the solvent. This effect of caldesmon, like its inhibitory effect on actomyosin ATPase activity, is enhanced in the presence of tropomyosin. Proteolytic removal of the last three COOH-terminal residues of actin, containing the modified cysteine residue, restores the normal binding between caldesmon and actin. These results establish a correlation between the binding of caldesmon to actin and the conformation of the COOH-terminal region of actin and suggest an indirect rather than direct interaction between caldesmon and this part of actin. Originally published Journal of Biological Chemistry, Vol. 266, No. 30, Oct 199

The Unimolecular Reaction Of (ch3)3cno Following N-π* Excitation With A Tunable Dye Laser

The predissociation of (CH3)3CNO following the 570-710 nm laser excitation of the n-π transition is reported. The small fluorescence quantum yield and its short lifetime (<20 ns) indicate efficient radiationless processes prior to dissociation. NO is the major dissociation product and its concentration was monitored in real time by using the two-photon laser excited fluorescence technique. The NO yield as a function of wavelength followed very closely the absorption contours of (CH3) 3CNO. The NO production rate was > 108 s-1 at all wavelengths studied and this rate is too fast to be consistent with a mechanism involving a radiationless transition to the ground electronic state followed by energy randomization and dissociation. Alternative predissociation mechanisms are considered. © 1983 American Institue of Physics.7863785379

Molecule-surface collision-induced dissociation of internally excited NO2 on MgO ( 100) *

- AbStl ¶lCt Collision-induced dissociation (CID) of highly excited NOs in the mixed 2A,/2B2 electronic system has been observed for well characterized MgO ( 100) surfaces with parent and product angular resolution at various internal energies. NO state distributions were probed by two-photon, two-frequency ionization, and its yield was found to track the NO2 absorption spectrum, confirming the CID mechanism. The angular dependence of the NO state distribution indicates that CID occurs following direct inelastic scattering rather than trapping-desorption