Scielo RSS http://www.scielo.cl/rss.php?pid=0717-345820130002&lang=en vol. 16 num. 2 lang. en http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200001&lng=en&nrm=iso&tlng=en Background: Haploid plant material is considered as recalcitrant to organogenesis, propagation, and maintenance in vitro. However, sugar beet (Beta vulgaris L.) breeders utilizing doubled haploid (DH) technology in their breeding programs indicate that sugar beet haploids may be cultured in vitro as well as diploids. Thus in this paper the in vitro performance of haploid and the doubled haploid sugar beet of various origin was evaluated. The DHs were derived from haploids by diploidization and twelve such haploid and corresponding DH clone pairs were obtained thus the comparison included haploid and DH clones that had identical allelic composition and differed only in their ploidy level. Results: The genotypes differed in shoot morphology and susceptibility to blackening during culture in vitro, but no significant differences were observed between the haploids and DHs. The micropropagation rate was, on average, higher for the haploids than DHs. Viability of the midrib and petiole explants after a 6-week culture was highly genotype dependent, but not affected by explant ploidy level. However, regeneration efficiency depended on both the genotype and ploidy level. The explants of several haploids regenerated more frequently and developed more adventitious shoots than the corresponding DHs thus overall efficiency was higher for haploids. Conclusions: The results obtained indicate that most of the haploids used in the comparison performed similar to or even better than DHs. This suggests that sugar beet haploid material can be successfully used not only for the production of DHs, but also maintained in vitro and utilized in projects requiring haploid tissues as the source material. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200002&lng=en&nrm=iso&tlng=en Background: Cyclophilin A (CypA), a receptor for the immunosuppressive agent cyclosporin A (CsA), is a cis-trans peptidyl-prolyl isomerase (PPIase) which accelerates the cis-trans isomerization of prolyl-peptide bonds and interacts with a variety of proteins to regulate their activities. Results: The full-length cDNA of crab Eriocheir sinensis CypA (EsCypA) was cloned by EST and RACE technique. The complete sequence of EsCypA cDNA contained a 5' untranslated region (UTR) of 50 bp, a 3’ UTR of 233 bp with a polyA tail, and an open reading frame (ORF) of 495 bp encoding a polypeptide of 164 amino acids with the predicted molecular weight of 17.36 kDa. The deduced amino acid sequence of EsCypA contained two highly conserved signature sequences of peptidyl-prolyl cis-trans isomerase and a pro-isomerase domain. The mRNA transcripts of EsCypA were detectable in all the examined tissues, including haemocytes, gill, hepatopancreas, gonad, muscle and heart, with higher expression level in hepatopancreas and gonad. No significant difference in the relative mRNA expression level of EsCypA was observed during the whole course of bacteria challenge, whereas it was up-regulated during fungi challenge. The purified recombinant protein rEsCypA exhibited a significant PPIase activity and an antifungal activity. Conclusions: All these results indicated that it was a typical CypA member and potentially involved in the innate immune responses of crab. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200003&lng=en&nrm=iso&tlng=en Background: Austrocedrus chilensis (D. Don) Pic. Ser. et Bizzarri commonly known as Patagonian cypress is a member of the Cupressaceae family, characterized by a high adaptive potential for growing in marginal areas and good timber quality. The species grows over a wide area and under a wide range of rainfall. This study assessed adaptive genetic variation at SNP level in candidate genes involved in response to drought stress. Results: A total of 18 single nucleotide polymorphisms (SNPs) were found among 1,428 bp. Average nucleotide diversity value (π = 0.00312) was similar to those previously reported in other Cupressaceae. The Fst average among genes and populations was 0.163 and the lowest differentiation was observed in continuous and humid populations. A number of neutrality tests were applied to find evidence of positive selection in our candidate gene set, but only AcAQP2 gene in Pedregoso and San Ramón populations revealed significant departures from neutrality with positive values suggesting balancing selection. Conclusions: In this study we report the levels of nucleotide diversity searched in some drought stress candidate genes in Austrocedrus chilensis and the selective factors that may be acting on this species. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200004&lng=en&nrm=iso&tlng=en Background: Modeling the kinetics of the biodesulphurization bioprocess for the refining of pyrite ash by Saccharomyces cerevisiae and Acetobacter aceti have been studied in batch-type liquid- state bioreactors. Results: The biodesulphurization experiments were performed at varying temperatures of 25ºC, 30ºC and 35ºC for eight weeks. Glucose, acetic acid and ethyl alcohol were used in the incubation media as substrates and acid sources. pH and oxidation reduction potential (ORP) observations have been determined weekly and the dissolved sulphur was measured at the end of the eight weeks trials. An equation calculating pH was derived from the iron oxidation reaction containing the ferric to ferrous iron [Fe+3/Fe+2] ratio as a variable. The Michaelis-Menten predictive specific growth rates (qFe+2), which were estimated from pH and ORP observations, were compared by plotting [qFe+²]pH vs. [qFe+2]mV. The highest ratio of dissolved sulphur over total sulphur (Sd/St) was found to be 0.5 in the biodesulphurization processes. Conclusions: The model provides predictions of ferric to ferrous iron rates and specific growth rates [qFe+²]pH vs. [qFe+2]mV and can be used for the determination of oxidized and reduced ions. The ratios of dissolved sulphur to total sulphur (Sd/St) have shown some promising results for S. cerevisiae to be used as a biodesulphurization and refining microorganism for pyrite ash and the other sulphide minerals. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200005&lng=en&nrm=iso&tlng=en Background: The ability for hydrogen production of 13 native strains of Clostridium spp. strains isolated from Colombian soil was evaluated using glycerol substrate. Glycerol to hydrogen conversion was investigated using a batch fermentation reactor and industrial glycerol source (50 g.l-1, pH 7.00). Results: The results were quantified regarding acids, hydrogen, biomass and solvent production. The selected strain gave good hydrogen over production output at 14.4 mmol H2.l-1, productivity 0.3167 mg H2.h-1 l-1 culture mediumand yield 0.1962 mol H2.mol-1 glycerol. A further fermentation assay a 4.0 liter batch reactor let to being 0.26 mg.l-1.h-1 after 18 hrs of fermentation. Logistic model, Luedeking-Piret model and Luedeking-Piret modified models were used for modeling changes in cell growth, hydrogen production and substrate consumption (Correlation coefficients R² = 0.95 for biomass substrate, R² = 0.77 hydrogen production). Conclusions: Our results indicate that hydrogen production through glycerol bioconversion by native strains is possible. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200006&lng=en&nrm=iso&tlng=en Background: The aim of this study was the production of xanthan gum from salts of volatile fatty acids, which can be generated in anaerobic processes for the production of hydrogen from organic wastewaters. Xanthan gum was produced with three different acid salts used to replace the traditional citrate, which is normally used in the culture for the production of this biopolymer. The volatile fatty acids (VFA) salts used were sodium acetate 0.0328 M, sodium propionate 0.0219 M, and sodium butyrate 0.0164 M. Results: The values of biomass yield, (Yp/x) obtained were 9.2 g/g for acetate, 11.78 g/g for citrate, 11.80 g/g for butyrate and 14.59 g/g for propionate, while the values of the product yield (Yp/s), were 0.92; 0.59; 0.71 and 0.72 for acetate, citrate, butyrate and propionate. As for the rheological characterization, the gums produced showed a consistency index (K) and flow index (n) of 9.8 dina.s-n.cm-2 and 0.34 for acetate; 6.3 dina.s-n.cm-2 and 0.39 for citrate, 5.8 dina.s-n.cm-2 and 0.45 for butyrate, 39.2 dina.s-n.cm-2 and 0.24 for propionate, that characterize the gums with good consistency and fluidity. Conclusions: It is possible to produce xanthan gum from short-chain volatile acids in replacement by the citrate that is usually used in medium composition for the gum production. These results contribute to the feasibility studies for implementation of processes for treating wastewater generating products such as volatile acids, hydrogen and consequent use of these acids for the production of xanthan gum. http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582013000200007&lng=en&nrm=iso&tlng=en Background: Retroviral vectors are commonly used for gene transfer applications and they represent an effective way to provide a sustained delivery of a bioactive factor in basic research and tissue engineering applications. Cells that have been transduced with retroviral vectors ex vivo are usually amplified on tissue culture plastic, for a prolonged period of time, in order to obtain sufficient cell numbers prior to the experiment of interest. However, the effect of the transgene product on the transduced cells, during this period of time, is rarely, if ever, investigated. The current study investigated if transduction with a VSG.G pseudotyped retroviral vector expressing human bone morphogenetic protein 2 (Rv.BMP-2) influences the gene expression profile of human bone marrow-derived mesenchymal stem cells (hMSCs) during monolayer proliferation. hMSCs that have been transduced with a VSG.G pseudotyped retroviral vector expressing enhanced green fluorescent protein (Rv.eGFP) served as controls. Results: It was confirmed that Rv.BMP-2 transduced hMSCs produce detectable amounts of bone morphogenetic protein 2 (BMP-2). Gene expression analysis revealed that the hypertrophic marker collagen X was down-regulated by approximately 50% and the chondrogenic marker Aggrecan was elevated almost 9-fold in Rv.BMP-2 transduced hMSCs if compared to Rv.eGFP transduced control cells. Interestingly, the same changes in gene expression were detected when hMSCs were exposed to 100 ng/ml of recombinant human BMP-2 and their gene expression profile was compared to control hMSC. Again, collagen X message was down-regulated and Aggrecan message was up-regulated. Conclusion: These results indicate that, when using integrating vectors and then expanding the cells after transduction, controls need to be carefully planned to ensure the results obtained during the 3D experiments are not due to artefacts created in response to the different cell proliferation conditions employed.