Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Nesting biology of the leafcutting bee Megachile (Pseudocentron) gomphrenoides (Hymenoptera: Megachilidae) in an agro-ecosystem

The nesting biology of the leafcutting bee Megachile (Pseudocentron) gomphrenoides Vachal (Hymenoptera: Megachilidae) was studied in an agro-ecosystem in the Province of Buenos Aires, Argentina. Data were obtained from trap-nests placed in the field margin during two agricultural years (2008/2009 and 2009/2010). Females made an average of 7.55 cells per nest, and used leaves of at least three plant species to build their nests. Provisions of cells were principally of Asteraceae pollen. Adult emergence showed a bimodal pattern suggesting a facultative bivoltinism life cycle. Approximately, 30 % of all offspring failed to complete development to the adult stage and an additional 10 % were killed by natural enemies. These included parasitic wasps (Eulophidae: Melittobia and Horismenus), a cleptoparasite bee (Megachilidae: Coelioxys), and a bristle beetle (Meloidae: Tetraonyx). The host/cleptoparasite association between M. gomphrenoides and Coelioxys remissa constitutes the first such record for both species, and the Megachile–Tetraonyx interaction was previously unknown. M. gomphrenoides possesses some characteristics that make it an interesting potential opportunity to use this species for pollination of commercial sunflowers in the Pampean region.Fil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durante, Silvana Patricia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Colombo, María Guadalupe. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Basilio, Alicia Mabel. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Producción Animal. Cátedra de Avicultura, Cunicultura y Apicultura; Argentin