Scielo RSS <![CDATA[Electronic Journal of Biotechnology]]> vol. 17 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<strong>Problem solving in enzyme biocatalysis</strong>]]> <![CDATA[<strong>The </strong><em><b>ICY1</b></em><strong> gene from </strong><em><b>Saccharomyces cerevisiae</b></em><strong> affects nitrogen consumption during alcoholic fermentation</strong>]]> Background Saccharomyces cerevisiae is the main microorganism responsible for alcoholic fermentation. In this process, the consumption of nitrogen is of great importance since it is found in limiting quantities and its deficiency produces sluggish and/or stuck fermentations generating large economic losses in the wine-making industry. In a previous work we compared the transcriptional profiles between genetically related strains with differences in nitrogen consumption, detecting genes with differential expression that could be associated to the differences in the levels of nitrogen consumed. One of the genes identified was ICY1. With the aim of confirming this observation, in the present work we evaluated the consumption of ammonium during the fermentation of strains that have deleted or overexpressed this gene. Results Our results confirm the effect of ICY1 on nitrogen uptake by evaluating its expression in wine yeasts during the first stages of fermentation under low (MS60) and normal (MS300) assimilable nitrogen. Our results show that the mRNA levels of ICY1 diminish when the amount of assimilable nitrogen is low. Furthermore, we constructed strains derived from the industrial strain EC1118 as a null mutant in this gene as well as one that overexpressed it. Conclusions Our results suggest that the expression of ICY1 is regulated by the amount of nitrogen available in the must and it is involved in the consumption of ammonium, given the increase in the consumption of this nitrogen source observed in the null mutant strain. <![CDATA[<strong>Effects of oligosaccharides from endophytic </strong><em><b>Fusarium oxysporum</b></em><strong> Dzf17 on activities of defense-related enzymes in </strong><em><b>Dioscorea zingiberensis</b></em><strong> suspension cell and seedling cultures</strong>]]> Background Three oligosaccharides (EOS, WOS and SOS) were respectively prepared from the corresponding polysaccharides, namely exopolysaccharide (EPS), water-extracted mycelial polysaccharide (WPS) and sodium hydroxide-extracted mycelial polysaccharides (SPS) from the endophytic fungus Fusarium oxysporum Dzf17. In this study, the effects of EOS, WOS and SOS on the activities of the defense-related enzymes, namely phenylalanine ammonia lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) in its host plant Dioscorea zingiberensis cultures were investigated. Results For the suspension cell cultures of D. zingiberensis, the highest PAL activity was induced by 0.5 mg/mL of WOS at 48 h after treatment, which was 4.55-fold as that of control. Both PPO and POD activities were increased to the maximum values by 0.25 mg/mL of WOS at 48 h after treatment, which were respectively 3.74 and 3.45-fold as those of control. For the seedling cultures, the highest PAL activity was elicited by 2.5 mg/mL of EOS at 48 h after treatment, which was 3.62-fold as that of control. Both PPO and POD reached their maximum values treated with 2.5 mg/mL of WOS at 48 h after treatment, which were 4.61 and 4.19-fold as those of control, separately. Conclusions Both EOS and WOS significantly increased the activities of PAL, PPO and POD in the suspension cell and seedling cultures of D. zingiberensis. The results suggested that the oligosaccharides from the endophytic fungus F. oxysporum Dzf17 may be related to the activation and enhancement of the defensive mechanisms of D. zingiberensis suspension cell and seedling cultures. <![CDATA[<strong>Expression profiles and polymorphism analysis of CDIPT gene on Qinchuan cattle</strong>]]> Background CDIPT (CDP-diacylglycerol-inositol 3-phosphatidyltransferase, EC was found on the cytoplasmic side of the Golgi apparatus and the endoplasmic reticulum. It was an integral membrane protein performing the last step in the de novo biosynthesis of phosphatidylinositol (PtdIns). In recent years, PtdIns has been considered to play an essential role in energy metabolism, fatty acid metabolic pathway and intracellular signal transduction in eukaryotic cells. Results In this study, the results of real-time polymerase chain reaction (PCR) showed that the expression of CDIPT gene was remarkably different in diverse tissues. We also detected the polymorphism of bovine CDIPT gene and analyzed its association with body measurement and meat quality traits of Qinchuan cattle. Blood samples were obtained from 638 Qinchuan cattle aged from 18 to 24 months. DNA sequencing and PCR-restriction fragment length polymorphism (RFLP) were used to find CDIPT gene single nucleotide polymorphism (SNP). Three SNPs g.244T>C (NCBI: rs42069760), g.1496G>A and g.1514G>A were found in this study. g.244T>C located at 5'untranslated region (5'UTR) of exon 1 showed three genotypes: TT, TC and CC. g.1496G>A and g.1514G>A detected the first time were located in intron 3 and showed the same genotypes: GG, GA and AA. Conclusions Analysis results showed that these three SNPs were significantly associated with body measurement traits (BMTs) and meat quality traits (MQTs). We suggested that CDIPT gene may have potential effects on BMTs and MQTs and can be used for marker-assisted selection. <![CDATA[<strong>Analysis of genetic diversity and differentiation of sheep populations in Jordan</strong>]]> Background Genetic diversity of sheep in Jordan was investigated using microsatellite markers (MS). Six ovine and bovine MS located on chromosomes 2 and 6 of sheep genome were genotyped on 294 individual from ten geographical regions. Results The number of alleles per locus (A), the expected heterozygosity (He) and observed heterozygosity (Ho) were measured. Overall A, He and Ho were 12.67, 0.820 and 0.684, respectively. On the other hand, genetic distances undoubtedly revealed the expected degree of differentiation among the studied populations. The finding showed closeness of three populations from south (Maan, Showbak and Tafeilah) to each other. Populations from the middle regions of Jordan (Karak, Madaba, Amman, AzZarqa and Mafraq) were found to be in one cluster. Only two populations of the middle region were an exception: AlSalt and Dead Sea. Finally, sheep populations from Irbid were located in separated cluster. It was clear that the studied predefined populations were subdivided from four populations and would be most probably accounted as ancestral populations. These results indicate that number of population is less than the predefined population as ten based on geographical sampling areas. Conclusions The possible inference might be that geographical location, genetic migration, similar selection forces, and common ancestor account for population admixture and subdivision of Awassi sheep breed in Jordan. Finally, the present study sheds new light on the molecular and population genetics of Awassi sheep from different regions of Jordan and to utilize the possible findings for future management of genetic conservation under conditions of climate changes and crossbreeding policy. <![CDATA[<strong>Bioaugmentation of latex rubber sheet wastewater treatment with stimulated indigenous purple nonsulfur bacteria by fermented pineapple extract</strong>]]> Background Treating latex rubber sheet wastewater often leads to the generation of a rotten-egg odor from toxic H2S. To increase the treatment efficiency and eliminate H2S, purple nonsulfur bacteria (PNSB), prepared by supplementing non-sterile rubber sheet wastewater (RAW) with fermented pineapple extract (FPE), were used to treat this wastewater under microaerobic light conditions. The following 3 independent variables: chemical oxygen demand (COD), initial pH and FPE dose were investigated using the Box-Behnken design to find optimal conditions for stimulating the growth of indigenous PNSB (PNSBsi). Results The addition of 2.0% FPE into RAW, which had a COD of 2000 mg L- 1 and an initial pH of 7.0, significantly decreased oxidation reduction potential (ORP) value and stimulated PNSBsi to reach a maximum of 7.8 log cfu mL- 1 within 2 d. Consequently, these PNSBsi, used as inoculants, were investigated for their ability to treat the wastewater under microaerobic light conditions. A central composite design was used to determine the optimal conditions for the wastewater treatment. These proved to be 7% PNSBsi, 0.8% FPE and 4 d retention time and this combination resulted in a reduction of 91% for COD, 75% for suspended solids, 61% for total sulfide while H2S was not detected. Results of abiotic control and treatment sets indicated that H2S was produced by heterotrophic bacteria and it was then effectively deactivated by PNSBsi. Conclusions The stimulation of PNSB growth by FPE under light condition was to lower ORP, and PNSBsi proved to be effective for treating the wastewater. <![CDATA[<strong>One-pot synthesis of graphene-chitosan nanocomposite modified carbon paste electrode for selective determination of dopamine</strong>]]> Background A simple, rapid, low-cost and environmentally friendly method was developed to determine dopamine (DA) in the presence of ascorbic (AA) and uric acid (UA) based on a novel technique to prepare a graphene-chitosan (GR-CS) nanocomposite and modify it on the surface of carbon paste electrode (CPE). For our design, CS acts as a media to disperse and stabilize GR, and then GR plays a key role to selective and sensitive determination of DA. Results Under physiological conditions, the linear range for dopamine was determined from 1 × 10- 4 to 2 × 10- 7 mol/L with a good correlation coefficient of 0.9961 in the presence of 1000-fold interference of AA and UA. The detection limit was estimated to be 9.82 × 10- 8 mol/L (S/N = 3). In order to study the stability and reproducibility, GR/CS/CPE underwent successive measurements in 10 times and then tested once a d for 30 d. The result exhibited 98.25% and 91.62% activities compared with the original peak current after 10-time measurements and 30-d storage. Conclusion The GR/CS/CPE has wide linear concentration range, low detection limit, and good reproducibility and stability, which suggests that our investigations provide a promising alternative for clinic DA determination. <![CDATA[<strong>A note on stability in food matrices of </strong><em><b>Salmonella enterica</b></em><strong> serovar Enteritidis-controlling bacteriophages</strong>]]> Background Lytic bacteriophages are bacterial viruses that upon infection kill their host cells and therefore have re-emerged as biological control agents of bacterial pathogens, particularly in the field of food related infections. Here, we investigated the stability in different food matrices of five phage isolates capable of controlling the foodborne pathogen Salmonella enterica serovar Enteritidis (SE). Results We found that two phages, originally isolated from food sources, were up to 5 logs more stable than three phages isolated from sewage, in ten food matrices (fresh and processed) at both 4°C and 18°C. Conclusion Lytic phages isolated from contaminated food sources seem to be a better choice when structuring phage cocktails to be used in the control of SE in food management protocols.