Scielo RSS <![CDATA[Electronic Journal of Biotechnology]]> http://www.scielo.cl/rss.php?pid=0717-345820160002&lang=es vol. 19 num. 2 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<strong>Bioconversion of agro-industrial wastes for the production of fibrinolytic enzyme from </strong><em><b>Bacillus halodurans </b></em><strong>IND18</strong>: <strong>Purification and biochemical characterization</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000200001&lng=es&nrm=iso&tlng=es Background: Agro-wastes were used for the production of fibrinolytic enzyme in solid-state fermentation. The process parameters were optimized to enhance the production of fibrinolytic enzyme from Bacillus halodurans IND18 by statistical approach. The fibrinolytic enzyme was purified, and the properties were studied. Results: A two-level full factorial design was used to screen the significant factors. The factors such as moisture, pH, and peptone were significantly affected enzyme production and these three factors were selected for further optimization using central composite design. The optimum medium for fibrinolytic enzyme production was wheat bran medium containing 1% peptone and 80% moisture with pH 8.32. Under these optimized conditions, the production of fibrinolytic enzyme was found to be 6851 U/g. The fibrinolytic enzyme was purified by 3.6-fold with 1275 U/mg specific activity. The molecular mass of fibrinolytic enzyme was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis, and it was observed as 29 kDa. The fibrinolytic enzyme depicted an optimal pH of 9.0 and was stable at a range of pH from 8.0 to 10.0. The optimal temperature was 60°C and was stable up to 50°C. This enzyme activated plasminogen and also degraded the fibrin net of blood clot, which suggested its potential as an effective thrombolytic agent. Conclusions: Wheat bran was found to be an effective substrate for the production of fibrinolytic enzyme. The purified fibrinolytic enzyme degraded fibrin clot. The fibrinolytic enzyme could be useful to make as an effective thrombolytic agent. <![CDATA[<strong>The accuracy of protein structure alignment servers</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000200002&lng=es&nrm=iso&tlng=es Background: Protein structural alignment is one of the most fundamental and crucial areas of research in the domain of computational structural biology. Comparison of a protein structure with known structures helps to classify it as a new or belonging to a known group of proteins. This, in turn, is useful to determine the function of protein, its evolutionary relationship with other protein molecules and grasping principles underlying protein architecture and folding. Results: A large number of protein structure alignment methods are available. Each protein structure alignment tool has its own strengths and weaknesses that need to be highlighted. We compared and presented results ofsix most popular and publically available servers for protein structure comparison. These web-based servers were compared with the respect to functionality (features provided by these servers) and accuracy (how well the structural comparison is performed). The CATH was used as a reference. The results showed that overall CE was top performer. DALI and PhyreStorm showed similar results whereas PDBeFold showed the lowest performance. In case of few secondary structural elements, CE, DALI and PhyreStorm gave 100% success rate. Conclusion: Overall none of the structural alignment servers showed 100% success rate. Studies of overall performance, effect of mainly alpha and effect of mainly beta showed consistent performance. CE, DALI, FatCat and PhyreStorm showed more than 90% success rate. <![CDATA[<strong>Enzymatic hydrolysis and fermentation of ultradispersed wood particles after ultrasonic pretreatment</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000200003&lng=es&nrm=iso&tlng=es Background: A study of the correlation between the particle size of lignocellulosic substrates and ultrasound pretreatment on the efficiency of further enzymatic hydrolysis and fermentation to ethanol. Results: The maximum concentrations of glucose and, to a lesser extent, di- and trisaccharides were obtained in a series of experiments with 48-h enzymatic hydrolysis of pine raw materials ground at 380-100 rpm for 30 min. The highest glucose yield was observed at the end of the hydrolysis with a cellulase dosage of 10 mg of protein (204 ±21 units CMCase per g of sawdust). The greatest enzymatic hydrolysis efficiency was observed in a sample that combined two-stage grinding at 400 rpm with ultrasonic treatment for 5-10 min at a power of 10 W per kg of sawdust. The glucose yield in this case (35.5 g glucose l-1) increased twofold compared to ground substrate without further preparation. Conclusions: Using a mechanical two-stage grinding of lignocellulosic raw materials with ultrasonication increases the efficiency of subsequent enzymatic hydrolysis and fermentation. <![CDATA[<strong>Identification and expression analysis of two </strong><em><b>Wnt4 </b></em><strong>genes in the spotted scat </strong><em><b>(Scatophagus argus)</b></em>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000200004&lng=es&nrm=iso&tlng=es Background: WNT4 is a protein that plays a crucial role in ovarian differentiation and development in mammals, with a relatively well understood function in mammalian gonadal differentiation. The role of WNT4 in teleost fish; however, remains unclear. In the present study, cDNAs of Wnt4a and Wnt4b were cloned and characterized in the spotted scat. The expression patterns of two Wnt4 genes in the gonads at different stages of development and in fish after treatment with 17a-methyltestosterone (MT) were investigated. Results: The tissue distribution showed that Wnt4a was expressed in various tissues, including the gonads, gills, spleen, brain, and fin. Interestingly, Wnt4b not only was expressed in the gills, brain, and spleen, but also was obviously expressed in the ovary. During gonad development, Wnt4a was highly expressed in the testis at stage I and Wnt4b was mainly expressed in the ovary at stages II-III. After MT treatment, the mRNA expression of Wnt4a increased significantly up to 40 d, and the transcript level of Wnt4b decreased at 20 d. Conclusions: These results suggest that Wnt4a may be involved in gonad development and plays a role in the process of spermatogonial proliferation. Our results also demonstrate that Wnt4b is not only expressed in the nervous system, but also in the ovary and it may be involved in ovary development of the spotted scat. <![CDATA[<strong>Chilean IPNV isolates</strong>: <strong>Robustness analysis of PCR detection</strong>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000200005&lng=es&nrm=iso&tlng=es Background: The genomes of several infectious pancreatic necrosis viruses (IPNVs) isolated in Chile were sequenced with a single amplification approach for both segments A and B. The resulting sequences were then used to determine the conservation of the primer-binding regions used in polymerase chain reaction (PCR)-based diagnostic methods proposed in the literature. Thus, the robustness of each technique was studied, particularly the eventual effect of further mutations within the primer-binding sites. Results: On analysis, most methods currently used to detect Chilean IPNV varieties were deemed adequate. However, the primers were designed to be genogroup specific, implying that most detection methods pose some risk of detecting all strains prevalent in the country, due to the coexistence of genogroups 1 and 5. Conclusions: Negative results must be interpreted carefully given the high genomic variability of IPNVs. Detection techniques (quantitative reverse transcription (qRT)-PCR) based on degenerate primers can be used to minimize the possibilities of false-negative detections.