Intersubunit Interactions Allowing a Carboxylate Mutant Coat Protein to Inhibit Tobamovirus Disassembly

AbstractTobacco mosaic tobamovirus (TMV) coat protein (CP) mutant E50Q lacks a repulsive intersubunit carboxylate group and can effectively inhibit the disassembly of wild-type TMV (Culveret al.,1995,Virology206,724). To investigate the ability of this mutant CP to block disassembly, a series of second-site amino acid substitutions were added to the E50Q CP. These second-site mutations were designed to disrupt specific intersubunit stabilizing interactions involving hydrophobic or polar residues, salt bridges, and CP–RNA contacts. Results showed substitutions disrupting intersubunit interactions that face the disassembling surface of the virion dramatically reduced the ability of CP E50Q to inhibit TMV disassembly. Substitutions that disrupted the CP inner loop, RNA binding capabilities, or intersubunit interactions that faced away from the disassembling surface did not dramatically interfere with CP E50Q's ability to inhibit disassembly. Taken together, these findings suggest that intersubunit interactions made by 5′ terminal E50Q subunits, not associated with RNA, provide the stabilizing forces that prevent virion disassembly. The role of these stabilizing interactions in TMV disassembly and their potential use for creating disassembly inhibiting CPs are discussed

Polyphenolic compounds and anthocyanin content of Prosopis nigra and Prosopis alba pods flour and their antioxidant and anti-inflammatory capacities

The aim of this study was to determine the content of total free and bound phenolic, free and bound flavonoid, anthocyanin, alkaloid and the profiles of polyphenols of the edible ripe pods of Prosopis alba and Prosopis nigra. P. alba flour showed significantly higher total (sum of Free- and Bound) phenolic content and total flavonoid compounds than P. nigra (P < 0.05) while P. nigra had higher concentrations of anthocyanins than P. alba (P < 0.05). The P. nigra flour shows a pattern characterized by the occurrence of anthocyanins (principally cyanidin-3-glucoside) as well as 14 flavonoid glycosides, with higher chemical diversity than P. alba, who shows 8 flavonoid glycosides as relevant constituents. The main compounds were quercetin O-glycosides and apigenin-based C-glycosides. The phenolic composition of two South American algarrobo pod flour is presented for the first time. The colour of the algarrobo pods is related to the content of anthocyanins. P. nigra pods having higher content of anthocyanins are darker (purple) than those of P. alba (light brown). Furthermore, the free sugar polyphenolic extracts of P. nigra and P. alba (phenolic-enriched Amberlite-retained fraction) as well as anthocyanins enriched extracts from P. nigra showed free radical scavenging activity. The P. nigra polyphenolic extracts showed activity against a pro-inflammatory enzyme (cyclooxygenase). In conclusion, algarrobo pods meal differing in colour contained biologicall active polyphenols, with possible positive impact in human health.Fil: Perez, Maria Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Cuello, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Zampini, Iris Catiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Ordóñez, Roxana Mabel. Universidad Nacional de Tucuman. Facultad de Cs.naturales E Instituto Miguel Lillo. Catedra de Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Alberto, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Quispe, Cristina. Universidad de Talca; ChileFil: Schmeda Hirschmann, Guillermo. Universidad de Talca; ChileFil: Isla, Maria Ines. Universidad Nacional de Tucuman. Facultad de Cs.naturales E Instituto Miguel Lillo. Catedra de Quimica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentin

Recommendation of short tandem repeat profiling for authenticating human cell lines, stem cells, and tissues

Cell misidentification and cross-contamination have plagued biomedical research for as long as cells have been employed as research tools. Examples of misidentified cell lines continue to surface to this day. Efforts to eradicate the problem by raising awareness of the issue and by asking scientists voluntarily to take appropriate actions have not been successful. Unambiguous cell authentication is an essential step in the scientific process and should be an inherent consideration during peer review of papers submitted for publication or during review of grants submitted for funding. In order to facilitate proper identity testing, accurate, reliable, inexpensive, and standardized methods for authentication of cells and cell lines must be made available. To this end, an international team of scientists is, at this time, preparing a consensus standard on the authentication of human cells using short tandem repeat (STR) profiling. This standard, which will be submitted for review and approval as an American National Standard by the American National Standards Institute, will provide investigators guidance on the use of STR profiling for authenticating human cell lines. Such guidance will include methodological detail on the preparation of the DNA sample, the appropriate numbers and types of loci to be evaluated, and the interpretation and quality control of the results. Associated with the standard itself will be the establishment and maintenance of a public STR profile database under the auspices of the National Center for Biotechnology Information. The consensus standard is anticipated to be adopted by granting agencies and scientific journals as appropriate methodology for authenticating human cell lines, stem cells, and tissues

Genomic analysis of codon, sequence and structural conservation with selective biochemical-structure mapping reveals highly conserved and dynamic structures in rotavirus RNAs with potential cis-acting functions

Rotaviruses are a major cause of acute, often fatal, gastroenteritis in infants and young children world-wide. Virions contain an 11 segment double-stranded RNA genome. Little is known about the cis-acting sequences and structural elements of the viral RNAs. Using a database of 1621 full-length sequences of mammalian group A rotavirus RNA segments, we evaluated the codon, sequence and RNA structural conservation of the complete genome. Codon conservation regions were found in eight ORFs, suggesting the presence of functional RNA elements. Using ConStruct and RNAz programmes, we identified conserved secondary structures in the positive-sense RNAs including long-range interactions (LRIs) at the 5′ and 3′ terminal regions of all segments. In RNA9, two mutually exclusive structures were observed suggesting a switch mechanism between a conserved terminal LRI and an independent 3′ stem–loop structure. In RNA6, a conserved stem–loop was found in a region previously reported to have translation enhancement activity. Biochemical structural analysis of RNA11 confirmed the presence of terminal LRIs and two internal helices with high codon and sequence conservation. These extensive in silico and in vitro analyses provide evidence of the conservation, complexity, multi-functionality and dynamics of rotavirus RNA structures which likely influence RNA replication, translation and genome packaging