Tissue culture of ornamental cacti

Cacti species are plants that are well adapted to growing in arid and semiarid regions where the main problem is water availability. Cacti have developed a series of adaptations to cope with water scarcity, such as reduced leaf surface via morphological modifications including spines, cereous cuticles, extended root systems and stem tissue modifications to increase water storage, and crassulacean acid metabolism to reduce transpiration and water loss. Furthermore, seeds of these plants very often exhibit dormancy, a phenomenon that helps to prevent germination when the availability of water is reduced. In general, cactus species exhibit a low growth rate that makes their rapid propagation difficult. Cacti are much appreciated as ornamental plants due to their great variety and diversity of forms and their beautiful short-life flowers; however, due to difficulties in propagating them rapidly to meet market demand, they are very often over-collected in their natural habitats, which leads to numerous species being threatened, endangered or becoming extinct. Therefore, plant tissue culture techniques may facilitate their propagation over a shorter time period than conventional techniques used for commercial purposes; or may help to recover populations of endangered or threatened species for their re-introduction in the wild; or may also be of value to the preservation and conservation of the genetic resources of this important family. Herein we present the state-of-the-art of tissue culture techniques used for ornamental cacti and selected suggestions for solving a number of the problems faced by members of the Cactaceae family

Aging and Environmental Enrichment Exacerbate Inflammatory Response on Antibody-Enhanced Dengue Disease in Immunocompetent Murine Model

We previously demonstrated in young mice that in comparison with animals raised in an impoverished environment (IE), animals from an enriched environment (EE) show more severe dengue disease, associated with an increased expansion of memory T target cells. Because active older adults show less functional decline in T-cell adaptive immunity, we hypothesized that aged mice from EE would show higher mortality and T-lymphocyte expansion than mice from IE. To test this hypothesis, we administered serial i.p. injections of anti-DENV2 hyperimmune serum, followed 24 h later by DENV3 (genotype III)-infected brain homogenate. Control mice received equal volumes of serum but received uninfected brain homogenate. The presence of virus or viral antigens was indirectly detected by real-time quantitative RT-PCR and immunohistochemistry. Compared to infected IE animals, EE mice, independent of age, showed higher mortality and more intense clinical signs. Compared to young mice, the higher mortality of aged mice was associated with a higher degree of T lymphocytic hyperplasia in the spleen and infiltration in kidneys, liver, and lungs, but less viral antigen immunolabeling. We propose that a higher expansion of T cells and serotype cross-reactive antibodies are associated with disease severity in aged mice