Development and application of a one-step low cost procedure to concentrate viruses from seawater samples

A novel and simple procedure for concentrating adenoviruses from seawater samples is described. The technique entails the adsorption of viruses to pre-flocculated skimmed milk proteins, allowing the flocs to sediment by gravity, and dissolving the separated sediment in phosphate buffer. Concentrated virus may be detected by PCR techniques following nucleic acid extraction. The method requires no specialized equipment other than that usually available in routine public health laboratories, and due to its straightforwardness it allows the processing of a larger number of water samples simultaneously. The usefulness of the method was demonstrated in concentration of virus in multiple seawater samples during a survey of adenoviruses in coastal waters

Mapping of calmodulin and G beta gamma binding domains within the C-terminal region of the metabotropic glutamate receptor 7A

Ca2+/calmodulin (Ca2+/CaM) and the subunits of heterotrimeric G-proteins (G) have recently been shown to interact in a mutually exclusive fashion with the intracellular C terminus of the presynaptic metabotropic glutamate receptor 7 (mGluR 7). Here, we further characterized the core CaM and G binding sequences. In contrast to a previous report, we find that the CaM binding motif localized in the N-terminal region of the cytoplasmic tail domain of mGluR 7 is conserved in the related group III mGluRs 4A and 8 and allows these receptors to also bind Ca2+/CaM. Mutational analysis of the Ca2+/CaM binding motif is consistent with group III receptors containing a conventional CaM binding site formed by an amphipathic -helix. Substitutions adjacent to the core CaM target sequence selectively prevent G binding, suggesting that the CaM-dependent regulation of signal transduction involves determinants that overlap with but are different from those mediating G recruitment. In addition, we present evidence that G uses distinct nonoverlapping interfaces for interaction with the mGluR 7 C-terminal tail and the effector enzyme adenylyl cyclase II, respectively. Although G-mediated signaling is abolished in receptors lacking the core CaM binding sequence, subunit activation, as assayed by agonist-dependent GTPS binding, was not affected. This suggests that Ca2+/CaM may alter the mode of group III mGluR signaling from mono- () to bidirectional ( and ) activation of downstream effector cascades. <br/

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