Resposta diferencial de genótipos de sorgo para tolerância ao alumínio em solução nutritiva.

Neste trabalho utilizou-se de uma tecnica de solucao nutritiva para identificar, dentre 391 linhagens de sorgo (BAG-Sorgo; 181), CNPMS: 71, SEPON/ICRISAT: 17 e Sacarino: 122, os genotipos que apresentam tolerancia ao aluminio. A avaliacao do comportamento diferencial dessas linhagens baseou-se no crescimento da raiz seminal primaria de plantas jovens de sorgo, em solucao nutritiva contendo niveis variados de Al (0,0, 2,25 e 4,5 mg de Al/1 para sorgo granifero e 0,0, 2,25 e 5,0 mg de Al/1 para sorgo sacarino). A caracteristica usada para a comparacao entre genotipos foi o Comprimento Relativo da Raiz Seminal (CRSS = CRS + AL/CRS - Al, onde CRS = comprimento da Raiz Seminal). Baseando-se na distribuicao percentual dos valores de CRRS obtidos para as diferentes linhagens e nos valores de CRRS encontrados para os materiais controles SC 298 (sensivel ao Al) e SC 283 (tolerante ao Al) tres classes de resposta ao aluminio foram definidas: Sensivel (CRRS 0,70). Dentre os materiais avaliados as seguintes linhagens apresentaram tolerancia aos niveis de 4,5 ou 5,0 mg de Al/1: IS 3625, IS 7173 C (SC 283), IS 12666, 5DX61/6/2, 3DX57/1/1910, 156-P-5-Serere-1, 9DX9/11, Brandes, MN 4004 e MN 1204

Temporary/Permanent Dual Cross-Link Gels Formed of a Bioactive Lactose-Modified Chitosan

Mounting evidences have recognized that dual cross-link and double-network gels can promisingly recapitulate the complex living tissue architecture and overcome mechanical limitations of conventional scaffolds used hitherto in regenerative medicine. Here, dual cross-link gels formed of a bioactive lactose-modified chitosan reticulated via both temporary (boric acid-based) and permanent (genipin-based) cross-linkers are reported. While boric acid rapidly binds to lactitol flanking diols increasing the overall viscosity, a slow temperature-driven genipin binding process takes place allowing for network strengthening. Combination of frequency and stress sweep experiments in the linear stress\u2013strain region shows that ultimate gel strength, toughness, and viscoelasticity depend on polymer-to-genipin molar ratio. Notably, herewith it is demonstrated that linear stretching correlates with strain energy dissipation through boric acid binding/unbinding dynamics. Strain-hardening effect in the nonlinear regime, along with good biocompatibility in vitro, points at an interesting role of present system as biological extracellular matrix substitute