Isolation and phylogenetic classification of culturable psychrophilic prokaryotes from the Collins glacier in the Antarctica.

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.

Phthalates and bisphenols migration in Mexican food cans and plastic food containers.

The presence of endocrine disruptors bisphenol-A, bisphenol-A-dimethacrylate, bisphenol-A-diglycidyl-ether, phthalic-acid, dibutyl-phthalate, diethyl-phthalate and dioctyl-phthalate was determined in vegetable cans, baby bottles and microwaveable containers from the Mexican market. Gas-Chromatography-Mass-Spectrometry was used for the identification and High-Performance-Liquid-Chromatography with UV/Visible light and fluorescence detectors was used for the quantification. Endocrine disruptors were found in all samples. PA and DOP were the substances most commonly found, and maximum concentrations were 9.549 and 0.664 µg/kg, respectively from a jalapeno peppers can. Bisphenol A, phthalic-acid, bisphenol-A-dimethacrylate, bisphenol-A-diglycidyl-ether, dioctyl-phtalate and dibutyl-phthalate were found in baby bottles and microwaveable containers.

Water stress induces up-regulation of DOF1 and MIF1 transcription factors and down-regulation of proteins involved in secondary metabolism in amaranth roots (Amaranthus hypochondriacus L.).

Roots are the primary sites of water stress perception in plants. The aim of this work was to study differential expression of proteins and transcripts in amaranth roots (Amaranthus hypochondriacus L.) when the plants were grown under drought stress. Changes in protein abundance within the roots were examined using two-dimensional electrophoresis and LC/ESI-MS/MS, and the differential expression of transcripts was evaluated with suppression subtractive hybridisation (SSH). Induction of drought stress decreased relative water content in leaves and increased solutes such as proline and total soluble sugars in roots. Differentially expressed proteins such as SOD(Cu-Zn) , heat shock proteins, signalling-related and glycine-rich proteins were identified. Up-regulated transcripts were those related to defence, stress, signalling (Ser, Tyr-kinases and phosphatases) and water transport (aquaporins and nodulins). More noteworthy was identification of the transcription factors DOF1, which has been related to several plant-specific biological processes, and MIF1, whose constitutive expression has been related to root growth reduction and dwarfism. The down-regulated genes/proteins identified were related to cell differentiation (WOX5A) and secondary metabolism (caffeic acid O-methyltransferase, isoflavone reductase-like protein and two different S-adenosylmethionine synthetases). Amaranth root response to drought stress appears to involve a coordinated response of osmolyte accumulation, up-regulation of proteins that control damage from reactive oxygen species, up-regulation of a family of heat shock proteins that stabilise other proteins and up-regulation of transcription factors related to plant growth control.

Tryptic amaranth glutelin digests induce endothelial nitric oxide production through inhibition of ACE: antihypertensive role of amaranth peptides.

Amaranth seed proteins have a better balance of essential amino acids than cereals and legumes. In addition, the tryptic hydrolysis of amaranth proteins generates, among other peptides, angiotensin converting enzyme (ACE) inhibitory (ACEi) peptides. ACE converts angiotensin I (Ang I) into Ang II, but is also responsible for the degradation of bradykinin (BK). In contrast to Ang II, BK stimulates vasodilation modulated through endothelial nitric oxide (NO) production. The aim of the present study was to characterize the ACEi activity of amaranth trypsin-digested glutelins (TDGs) and their ability to induce endothelial NO production. An IC(50) value of 200microgml(-1) was measured for TDG inhibition of ACE. TDGs stimulated endothelial NO production in coronary endothelial cells (CEC) by 52% compared to control. The effects of TDGs were comparable to those of BK and Captopril, both used as positive controls of NO production. Consistent with these effects, TDGs induced, in a dose-dependent manner, endothelial NO-dependent vasodilation in isolated rat aortic rings. These results suggest that TDGs induce endothelial NO production and consequent vasodilation through their ACEi activity. Amaranth TDGs have a high potential as a nutraceutical food in prevention of cardiovascular diseases. Further molecular, cellular and physiological studies are currently under way and the results may contribute to a better understanding and control of cardiovascular disorders.

Online monitoring of Mezcal fermentation based on redox potential measurements.

We describe an algorithm for the continuous monitoring of the biomass and ethanol concentrations as well as the growth rate in the Mezcal fermentation process. The algorithm performs its task having available only the online measurements of the redox potential. The procedure combines an artificial neural network (ANN) that relates the redox potential to the ethanol and biomass concentrations with a nonlinear observer-based algorithm that uses the ANN biomass estimations to infer the growth rate of this fermentation process. The results show that the redox potential is a valuable indicator of the metabolic activity of the microorganisms during Mezcal fermentation. In addition, the estimated growth rate can be considered as a direct evidence of the presence of mixed culture growth in the process. Usually, mixtures of microorganisms could be intuitively clear in this kind of processes; however, the total biomass data do not provide definite evidence by themselves. In this paper, the detailed design of the software sensor as well as its experimental application is presented at the laboratory level.

Identification of yeast and bacteria involved in the mezcal fermentation of Agave salmiana.

AIMS: To identify the yeast and bacteria present in the mezcal fermentation from Agave salmiana. METHODS AND RESULTS: The restriction and sequence analysis of the amplified region, between 18S and 28S rDNA and 16S rDNA genes, were used for the identification of yeast and bacteria, respectively. Eleven different micro-organisms were identified in the mezcal fermentation. Three of them were the following yeast: Clavispora lusitaniae, Pichia fermentans and Kluyveromyces marxianus. The bacteria found were Zymomonas mobilis subsp. mobilis and Zymomonas mobilis subsp. pomaceae, Weissella cibaria, Weissella paramesenteroides, Lactobacillus pontis, Lactobacillus kefiri, Lactobacillus plantarum and Lactobacillus farraginis. CONCLUSIONS: The phylogenetic analysis of 16S rDNA and ITS sequences showed that microbial diversity present in mezcal is dominated by bacteria, mainly lactic acid bacteria species and Zymomonas mobilis. Pichia fermentans and K. marxianus could be micro-organisms with high potential for the production of some volatile compounds in mezcal. SIGNIFICANCE AND IMPACT OF THE STUDY: We identified the community of bacteria and yeast present in mezcal fermentation from Agave salmiana.

Bioactive peptides in amaranth (Amaranthus hypochondriacus) seed.

Amaranth seeds are rich in protein with a high nutritional value, but little is known about their bioactive compounds that could benefit health. The objectives of this research were to investigate the presence, characterization, and the anticarcinogenic properties of the peptide lunasin in amaranth seeds. Furthermore, to predict and identify other peptides in amaranth seed with potential biological activities. ELISA showed an average concentration of 11.1 microg lunasin equivalent/g total extracted protein in four genotypes of mature amaranth seeds. Glutelin fraction had the highest lunasin concentration (3.0 microg/g). Lunasin was also identified in albumin, prolamin and globulin amaranth protein fractions and even in popped amaranth seeds. Western blot analysis revealed a band at 18.5 kDa, and MALDI-TOF analysis showed that this peptide matched more than 60% of the soybean lunasin peptide sequence. Glutelin extracts digested with trypsin, showed the induction of apoptosis against HeLa cells. Prediction of other bioactive peptides in amaranth globulins and glutelins were mainly antihypertensive. This is the first study that reports the presence of a lunasin-like peptide and other potentially bioactive peptides in amaranth protein fractions.

Modified penicillin acylase signal peptide allows the periplasmic production of soluble human interferon-gamma but not of soluble human interleukin-2 by the Tat pathway in Escherichia coli.

Production of periplasmic human interferon-gamma (hINF-gamma) and human interleukin-2 (hIL-2) by the Tat translocation pathway in Escherichia coli BL21-SI was evaluated. The expression was obtained using the pEMR vector which contains the Tat-dependent modified penicillin acylase signal peptide (mSPpac) driven by the T7 promoter. The mSPpac-hINF-gamma was processed and the protein was transported to periplasm. Up to 30.1% of hINF-gamma was found in the periplasmic soluble fraction, whereas only 15% of the mSPpac-hIL-2 was processed, but hIL-2 was not found in the periplasmic soluble fraction.

A novel binary expression vector for production of human IL-10 in Escherichia coli and Bifidobacterium longum.

A novel expression vector (pLR) driven by hup promoter and Bifidobacterium beta-galactosidase signal peptide was constructed. The pLR vector was used for the expression of the optimized human IL-10 synthetic gene in Escherichia coli and Bifidobacterium longum. In both microorganisms, rhIL-10 was in a soluble form in total extract cells. The recombinant hIL-10 was partially processed in E. coli, whereas in Bifidobacterium all rhIL-10 was found in the mature form.

Expression and purification of rotavirus proteins NSP5 and NSP6 in Escherichia coli.

Rotaviruses are one of the worldwide leading causes of gastroenteritis in children under 5 yr old. The rotavirus nonstructural NSP5 is a phosphoprotein implicated in viroplasms formation, whereas NSP6 could have a possible regulatory role of NSP5. It has been reported that N- and C-termini of NSP5 are important for their function. However, no structural information on NSP5 and NSP6 proteins is available. Because a high amount of protein is required for structural analysis, efficient expression systems are required. His-tag fusion at the C-terminus and glutathione-S-transferase (GST)-fusion at the N-terminus were used as expression systems, and conditions for recombinant proteins expression were obtained. His-tag fusion was not efficient to produce NSP5 (2% of total protein), but NSP6 was expressed in higher amounts (11% of total protein). In contrast, GSTNSP5 and GST-NSP6 proteins correspond to 34 and 31% of the total proteins, respectively. GST-fusions seem to have a protective effect against nonstructural rotavirus protein toxicity in Escherichia coli; however, in both systems, NSP5 and NSP6 recombinant proteins were expressed as inclusion bodies. Conditions for solubilization and purification of recombinant proteins were achieved. This is the first report of expression and purification of NSP5 and NSP6 recombinant proteins in suitable amounts for further structural analysis.

Functional and rheological properties of amaranth albumins extracted from two Mexican varieties.

The functional and rheological properties of amaranth albumins isolates extracted from two new Mexican varieties were determined. Functional properties tested were protein solubility, foaming, water and oil absorption capacities, emulsifying activity, and emulsion stability. The maximum solubility values for both amaranth albumins were found above pH 6 and values were compared to the solubility of egg albumins. Albumins from amaranth showed excellent foaming capacity and foaming stability at pH 5, suggesting that this protein could be used as whipping agents as egg albumins, also the water and oil absorption capacities reached their maximum values at acidic pH, suggesting that amaranth albumins could be appropriate in preparation of acidic foods. The rheological test based on farinograms and alveograms showed that wheat flour supplemented with 1% amaranth albumins improves the dough properties due to higher mixing stability and the bread had better crumb characteristics. In addition of the known high nutritional values of amaranth albumins, our results indicate the high potential for use of these proteins as an ingredient in food preparations.