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Luna-Suarez S.,Research Center en Biotecnologia Aplicada | Medina-Godoy S.,Centro Interdisciplinario Of Investigacion Para El Desarrollo Integral Regional | Cruz-Hernandez A.,CINVESTAV | Paredes-Lopez O.,CINVESTAV
Journal of Biotechnology

Amarantin is the predominant seed storage protein from amaranth. It shows a high content of essential amino acids, making this protein important from a nutritional viewpoint. The protein has two disulfide linked subunits: acidic and basic. Acidic subunit has the potential as a functional and nutraceutical protein, and it is structurally a good candidate for modification. In order to improve its functionality, the primary structure was modified in the third variable region of globulins 11S, by inserting four Val-Tyr antihypertensive peptides in tandem. The designed plasmid was expressed in Escherichia coli Origami (DE3) and then the expressed protein was purified. Mass spectrometry analysis was used to corroborate the identity of the protein by peptide mass fingerprinting; also, the modified peptide was fragmented and sequenced by mass spectrometry, corroborating thus the inserted residues. The hydrolyzed protein showed a high inhibitory activity of the angiotensin converting enzyme (IC 50 0.064mgml -1); it was nearly eightfold more active than the nonmodified protein. In spite that the nonmodified subunit is less active, its activity is comparable with other hydrolyzed proteins reported as high active inhibitors. The expressed and purified subunit after its engineered modification, may be useful for preventing hypertension and for other medical purposes. © 2010 Elsevier B.V. Source

Castro-Martinez C.,Research Center para el Desarrollo Integral Regional | Luna-Suarez S.,Research Center en Biotecnologia Aplicada | Paredes-Lopez O.,CINVESTAV
Journal of Biotechnology

Amaranth seeds are considered as an excellent complementary source of food protein due to their balanced amino acid composition. Amarantin acidic subunit has the potential as a functional and nutraceutical protein, and it is structurally a good candidate for modification. The aim of this work was to improve its functionality, then the primary structure was modified into the third variable region of 11S globulins, by inserting antihypertensive peptides: four Val-Tyr in tandem and Arg-Ile-Pro-Pro in the C-terminal region. Modified protein was expressed in Escherichia coli Origami (DE3) and was purified. The culture conditions, including the culture media, temperature, agitation speed and air flow were tested in order to obtain an increased expression levels of the modified protein. A 2 3 factorial design was used for evaluate the effect of environmental conditions on modified protein production. The results indicated that the yield of modified protein could be increased by up 3-fold in bioreactor as compared with flask. In addition, the temperature, the agitation speed and the oxygen were significant factors on the expression of the antihypertensive protein. The maximum production was 99mg protein-L -1. The hydrolyzed protein showed a high inhibitory activity of the angiotensin converting enzyme (IC 50=0.047mgmL -1). © 2012 Elsevier B.V. Source

Diaz R.,Autonomous University of Tlaxcala | Alonso S.,Autonomous University of Tlaxcala | Sanchez C.,Autonomous University of Tlaxcala | Tomasini A.,Metropolitan Autonomous University | And 2 more authors.

Kinetic parameters of growth and laccase activity of five ATCC strains of Pleurotus ostreatus in submerged fermentation were evaluated. The best strain for laccase production and the time of maximum laccase activity were also determined. The greatest laccase activity (37490 U/L), laccase productivity (78 U/L h), specific growth rate (0.026/h), and specific rate of laccase production (119 U/gX h) were observed with the strain of P. ostreatus ATCC 32783. In general, the isoenzyme patterns were different in all the cases; however, all the strains showed two laccase bands in the same position in the gel. Not all strains responded in the same way to the addition of Cu in the culture medium. In general, the sensitivity to Cu could be used to select strains having high laccase activity for commercial exploitation. Source

Troconis-Torres I.G.,National Polytechnic Institute of Mexico | Rojas-Lopez M.,Research Center en Biotecnologia Aplicada | Hernandez-Rodriguez C.,National Polytechnic Institute of Mexico | Villa-Tanaca L.,National Polytechnic Institute of Mexico | And 4 more authors.
Journal of Biomedicine and Biotechnology

The genus Capsicum provides antioxidant compounds, such as phenolics and carotenoids, into the diet. In Mexico, there is a wide diversity of species and varieties of chilli peppers, a fruit which has local cultural and gastronomic importance. In the present study, the relationship of the carotenoid and phenolic profiles with the RAPD fingerprint of three different commercial cultivars of chilli peppers of seven regions of Mexico was investigated. Through RAPD, the species of chilli were differentiated by means of different primers (OPE-18, MFG-17, MFG-18, C51, and C52). The genetic distance found with OPE 18 was in the order of 2.6. The observed differences were maintained when the chromatographic profile of carotenoids, and the molecular markers were analyzed, which suggest a close relationship between carotenoids and the genetic profile. While the chromatographic profile of phenols and the molecular markers were unable to differentiate between genotypes of chilli peppers. In addition, by using infrared spectroscopy and statistical PCA, differences explained by geographic origin were found. Thus, this method could be an alternative for identification of chilli species with respect to their geographic origin. Copyright © 2012 Ivonne Guadalupe Troconis-Torres et al. Source

Miche L.,IRD Montpellier | Miche L.,Aix - Marseille University | Moulin L.,IRD Montpellier | Chaintreuil C.,IRD Montpellier | And 6 more authors.
Environmental Microbiology

Tropical aquatic legumes of the genus Aeschynomene are unique in that they can be stem-nodulated by photosynthetic bradyrhizobia. Moreover, a recent study demonstrated that two Aeschynomene indica symbionts lack canonical nod genes, thereby raising questions about the distribution of such atypical symbioses among rhizobial-legume interactions. Population structure and genomic diversity were compared among stem-nodulating bradyrhizobia isolated from various Aeschynomene species of Central America and Tropical Africa. Phylogenetic analyses based on the recA gene and whole-genome amplified fragment length polymorphism (AFLP) fingerprints on 110 bacterial strains highlighted that all the photosynthetic strains form a separate cluster among bradyrhizobia, with no obvious structuring according to their geographical or plant origins. Nod-independent symbiosis was present in all sampling areas and seemed to be linked to Aeschynomene host species. However, it was not strictly dependent on photosynthetic ability, as exemplified by a newly identified cluster of strains that lacked canonical nod genes and efficiently stem-nodulated A. indica, but were not photosynthetic. Interestingly, the phenotypic properties of this new cluster of bacteria were reflected by their phylogenetical position, as being intermediate in distance between classical root-nodulatingBradyrhizobium spp. and photosynthetic ones. This result opens new prospects about stem-nodulating bradyrhizobial evolution. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd. Source

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