Barrientos-Diaz, L., Gidekel, M., & Gutierrez-Moraga, A. (2008). Characterization of rhizospheric bacteria isolated from Deschampsia antarctica Desv. World J. Microbiol. Biotechnol., 24(10), 2289–2296.
Abstract: Deschampsia antarctica Desv. is the only gramineae capable of colonizing the Antarctic due to the region's extreme climate and soil environment. In the present research, bacteria colonizing the rhizospheric soil of D. antarctica were isolated and characterized. The soil studies showed that D. antarctica possesses a wide spectrum of psychrotolerant bacteria with extensive and varied antibiotic resistance, as well as heavy metal tolerance. The bacterial strains isolated from the rhizosphere of D. antarctica also produced a diverse pattern of enzymes. Based on the strain identification with partial characterization of the 16S rRNA gene, the majority of the isolates correspond to different Pseudomonas species, and species of the genus Flavobacterium sp. and Arthrobacter sp. The isolated strains collected from this research constitute a unique collection for future, more detailed taxonomic analysis and physiological characterization, contributing to the search for potential biotechnological uses. These findings and others have great potential for developing new biotechnological products from Antarctic microorganisms.
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Garcia-Echauri, S. A., Gidekel, M., Gutierrez-Moraga, A., Santos, L., & De Leon-Rodriguez, A. (2011). Isolation and phylogenetic classification of culturable psychrophilic prokaryotes from the Collins glacier in the Antarctica. Folia Microbiol., 56(3), 209–214.
Abstract: Culturable psychrophilic prokaryotes were obtained of samples of glacier sediment, seaside mud, glacier melted ice, and Deschampsia antarctica rhizosphere from Collins glacier, Antarctica. The taxonomic classification was done by a culture-dependent molecular approach involving the Amplified Ribosomal DNA Restriction Analysis. Two hundred sixty colonies were successfully isolated and sub-cultivated under laboratory conditions. The analysis showed a bacterial profile dominated by Beta-proteobacteria (35.2%) followed by Gamma-proteobacteria (18.5%), Alpha-proteobacteria (16.6%), Gram-positive with high GC content (13%), Cytophaga-Flavobacterium-Bacteroides (13%) and Gram-positive with low GC content (3.7%). Eleven of the isolates have been reported previously and the others microorganisms remain uncharacterized. The isolated microorganisms here could be a potential source for biotechnological products, such as cold-active enzymes and secondary metabolites.
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Osorio, J., Calderon, C., Gutierrez-Moraga, A., & Gidekel, M. (2014). The effects of growth regulators and a scanning electron microscope study of somatic embryogenesis in Antartic hair grass (Deschampsia antarctica Desv.). Polar Biol., 37(2), 217–225.
Abstract: Deschampsia antartctica Desv. is a type of grass that is physiologically and biochemically adapted to the extreme environmental conditions of the Antarctic continent, which is of interest to many investigators. To explore the potential use of somatic embryogenesis as a biotechnological tool for the mass micropropagation of this grass, the effects of three dosages of 2,4-dichlorophenoxyacetic acid, dicamba, and picloram were evaluated. The developmental and morphological stages of somatic embryo formation were evaluated using scanning electron microscopy (SEM). Plant regeneration was evaluated under the effects of different dosages of 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA), alone and combined. The results indicated that a Murashige and Skoog basal medium supplemented with 3 mg/l of dicamba was the best for inducing somatic embryogenesis, while the combination of 1 mg/l BAP and 0.1 mg/l of NAA was the most efficient for the regeneration and development of the plants. This work demonstrates, for the first time with the use of SEM, that it is possible to apply somatic embryogenesis for the regeneration of superficial and morphological structures of somatic embryos in the species D. antarctica.
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Taboada, E., Fisher, P., Jara, R., Zuniga, E., Gidekel, M., Cabrera, J. C., et al. (2010). Isolation and characterisation of pectic substances from murta (Ugni molinae Turcz) fruits. Food Chem., 123(3), 669–678.
Abstract: Cell walls polysaccharides from murta fruit (Ugni molinae Turcz), an endemic Chilean species with relevant food uses, were fractionated by water, ammonium oxalate, hot diluted HCl and cold diluted NaOH extractions. The polysaccharide fractions were analysed for monosaccharide composition and physicochemical properties. Pectic substances were found in all extracts, but mainly in the oxalate and acid soluble fractions, in which they appear as homogalacturonan polymers. Murta pectin was further extracted by hot diluted acid treatment using industrial conditions, yielding 30% by weight of dry fruit. The polymer showed similar composition and physicochemical properties to those of commercial citrus pectin, presenting a galacturonic acid content of 70.9% (w/w), a molecular weight of 597 kDa, and a methoxylation degree of 57%. The FT-IR spectrum of murta pectin suggests the presence of ferulic acid residues on its structure and the NMR analysis confirmed the structure of this polysaccharide. It is concluded that murta fruit can be considered as a valuable source of high quality pectin. (C) 2010 Elsevier Ltd. All rights reserved.
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