Transformation of Saccharomyces cerevisiae with linear DNA killer plasmids from Kluyveromyces lactis.

PubMed Central

Gunge, N; Murata, K; Sakaguchi, K

1982-01-01

Protoplasts of Saccharomyces cerevisiae were mixed with linear DNA plasmids, pGKl1 and pGKl2, isolated from a Kluyveromyces lactis killer strain and treated with polyethylene glycol. Out of 2,000 colonies regenerated on a nonselective medium, two killer transformants were obtained. The pGKl plasmids and the killer character were stably maintained in one (Pdh-1) of them. Another transformant, Pdl-1, was a weak killer, and the subclones consisted of a mixture of weak and nonkiller cells. The weak killers were characterized by the presence of pGKl1 in a decreased amount, and nonkillers were characterized by the absence of pGKl1. The occurrence of two new plasmids which migrated faster than pGKl1 in an agarose gel was observed in Pdl-1 and its subclones, whether weak or nonkillers. Staining with 4',6-diamidino-2-phenylindole revealed that the pGKl plasmids exist in the cytosol of transformant cells with numerous copy numbers. Images PMID:7045080

Lactose-induced cell death of beta-galactosidase mutants in Kluyveromyces lactis.

PubMed

Lodi, Tiziana; Donnini, Claudia

2005-05-01

The Kluyveromyces lactis lac4 mutants, lacking the beta-galactosidase gene, cannot assimilate lactose, but grow normally on many other carbon sources. However, when these carbon sources and lactose were simultaneously present in the growth media, the mutants were unable to grow. The effect of lactose was cytotoxic since the addition of lactose to an exponentially-growing culture resulted in 90% loss of viability of the lac4 cells. An osmotic stabilizing agent prevented cells killing, supporting the hypothesis that the lactose toxicity could be mainly due to intracellular osmotic pressure. Deletion of the lactose permease gene, LAC12, abolished the inhibitory effect of lactose and allowed the cell to assimilate other carbon substrates. The lac4 strains gave rise, with unusually high frequency, to spontaneous mutants tolerant to lactose (lar1 mutation: lactose resistant). These mutants were unable to take up lactose. Indeed, lar1 mutation turned out to be allelic to LAC12. The high mutability of the LAC12 locus may be an advantage for survival of K. lactis whose main habitat is lactose-containing niches.

Ethanol inhibition kinetics of Kluyveromyces marxianus grown on Jerusalem artichoke juice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bajpai, P.; Margaritis, A.

1982-12-01

The kinetics of ethanol inhibition on cell growth and ethanol production by Kluyveromyces marxianus UCD (FST) 55-82 were studied during batch growth. The liquid medium contained 10% (weight/volume) inulin-type sugars derived from an extract of Jerusalem artichoke (Helianthus tuberosus) tubers, supplemented with small amounts of Tween 80, oleic acid, and corn steep liquor. Initial ethanol concentrations ranging from 0 to 80 g/liter in the liquid medium were used to study the inhibitory effect of ethanol on the following parameters: maximum specific growth rate (mu max), cell and ethanol yields, and sugar utilization. It was found that as the initial ethanolmore » concentration increased from 0 to 80 g/liter, and maximum specific growth rate of K. marxianus cells decreased from 0.42 to 0.09/hour, whereas the ethanol and cell yields and sugar utilization remained almost constant. A simple kinetic model was used to correlate the mu max results and the rates of cell and ethanol production, and the appropriate constants were evaluated. (Refs. 22).« less

Construction of recombinant Kluyveromyces marxianus UFV-3 to express dengue virus type 1 nonstructural protein 1 (NS1).

PubMed

Bragança, Caio Roberto Soares; Colombo, Lívia Tavares; Roberti, Alvaro Soares; Alvim, Mariana Caroline Tocantins; Cardoso, Silvia Almeida; Reis, Kledna Constancio Portes; de Paula, Sérgio Oliveira; da Silveira, Wendel Batista; Passos, Flavia Maria Lopes

2015-02-01

The yeast Kluyveromyces marxianus is a convenient host for industrial synthesis of biomolecules. However, despite its potential, there are few studies reporting the expression of heterologous proteins using this yeast. Here, we report expression of a dengue virus protein in K. marxianus for the first time. The dengue virus type 1 nonstructural protein 1 (NS1) was integrated into the K. marxianus UFV-3 genome at the LAC4 locus using an adapted integrative vector designed for high-level expression of recombinant protein in Kluyveromyces lactis. The NS1 gene sequence was codon-optimized to increase the level of protein expression in yeast. The synthetic gene was cloned in frame with K. lactis α-mating factor signal peptide, and the recombinant plasmid obtained was used to transform K. marxianus UFV-3 by electroporation. The transformed cells, selected in yeast extract peptone dextrose containing 200 μg mL(-1) Geneticin, were mitotically stable. Analysis of recombinant strains by RT-PCR and protein detection using blot analysis confirmed both transcription and expression of extracellular NS1 polypeptide. After induction with galactose, the NS1 protein was analyzed by sodium dodecyl sulfate-PAGE and immunogenic detection. Protein production was investigated under two conditions: with galactose and biotin pulses at 24-h intervals during 96 h of induction and without galactose and biotin supplementation. Protease activity was not detected in post-growth medium. Our results indicate that recombinant K. marxianus is a good host for the production of dengue virus NS1 protein, which has potential for diagnostic applications.

Fermentation and aerobic metabolism of cellodextrins by yeasts. [Candida wickerhamii; C. guiliermondii; C. molischiana; Debaryomyces polymorphus; Pichia guilliermondii; Clavispora lusitaniae; Kluyveromyces lactis; Brettanomyces claussenii; Rhodotorula minuta; Dekkera intermedia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freer, S.N.

1991-03-01

The fermentation and aerobic metabolism of cellodextrins by 14 yeast species or strains was monitored. When grown aerobically, Candida wickerhamii, C. guilliermondii, and C. molischiana metabolized cellodextrins of degree of polymerization 3 to 6. C. wicherhamii and C. molischiana also fermented these substrates, while C. guilliermondii fermented only cellodextrins of degree of polymerization {<=} 3. Debaryomyces polymorphus, Pichia guilliermondii, Clavispora lusitaniae, and one of two strains of Kluyveromyces lactis metabolized glucose, cellobiose, and cellotriose when grown aerobically. These yeasts also fermented these substrates, except for K. lactis, which fermented only glucose and cellobiose. The remaining species/strains tested, K. lactis, Brettanomycesmore » claussenii, Brettanomyces anomalus, Kluyveromyces dobzhanskii, Rhodotorula minuta, and Dekkera intermedia, both fermented and aerobically metabolized glucose and cellobiose. Crude enzyme preparations from all 14 yeast species or strains were tested for ability to hydrolyze cellotriose and cellotretose. Most of the yeasts produced an enzyme(s) capable of hydrolyzing cellotriose. However, with two exceptions, R. minuta and P. guilliermondii, only the yeasts that metabolized cellodextrins of degree of polymerization >3 produced an enzyme(s) that hydrolyzed cellotretose.« less

Bioproduction of 2-phenylethanol and 2-phenethyl acetate by Kluyveromyces marxianus through the solid-state fermentation of sugarcane bagasse.

PubMed

Martínez, Oscar; Sánchez, Antoni; Font, Xavier; Barrena, Raquel

2018-06-01

2-Phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) are important aroma compounds widely used in food and cosmetic industries due to their rose-like odor. Nowadays, due to the growing demand for natural products, the development of bioprocesses for obtaining value-added compounds has become of great significance. 2-PE and 2-PEA can be produced through the biotransformation of L-phenylalanine using the generally recognized as safe strain Kluyveromyces marxianus. L-phenylalanine bioconversion systems have been typically focused on submerged fermentation processes (SmF), but there is no information about other alternative productive approaches. Here, the solid-state fermentation (SSF) of sugarcane bagasse supplemented with L-phenylalanine was investigated as a sustainable alternative for producing 2-PE and 2-PEA in a residue-based system using Kluyveromyces marxianus as inoculum. An initial screening of the operational variables indicated that air supply, temperature, and initial moisture content significantly affect the product yield. Besides, it was found that the feeding strategy also affects the production and the efficiency of the process. While a basic batch system produced 16 mg products per gram of residue (dry basis), by using split feeding strategies (fed-batch) of only sugarcane bagasse, a maximum of 18.4 mg Products  g -1 residue were achieved. Increase in product yield was also accompanied by an increase in the consumption efficiency of nutrients and precursor. The suggested system results as effective as other more complex SmF systems to obtain 2-PE and 2-PEA, showing the feasibility of SSF as an alternative for producing these compounds through the valorization of an agro-industrial residue.

Effect of lignocellulosic degradation compounds from steam explosion pretreatment on ethanol fermentation by thermotolerant yeast Kluyveromyces marxianus.

PubMed

Oliva, Jose Miguel; Sáez, Felicia; Ballesteros, Ignacio; González, Alberto; Negro, Maria José; Manzanares, Paloma; Ballesteros, Mercedes

2003-01-01

The filtrate from steam-pretreated poplar was analyzed to identify degradation compounds. The effect of selected compounds on growth and ethanolic fermentation of the thermotolerant yeast strain Kluyveromyces marxianus CECT 10875 was tested. Several fermentations on glucose medium, containing individual inhibitory compounds found in the hydrolysate, were carried out. The degree of inhibition on yeast strain growth and ethanolic fermentation was determined. At concentrations found in the prehy-drolysate, none of the individual compounds significantly affected the fermentation. For all tested compounds, growth was inhibited to a lesser extent than ethanol production. Lower concentrations of catechol (0.96 g/L) and 4-hydroxybenzaldehyde (1.02 g/L) were required to produce the 50% reduction in cell mass in comparison to other tested compounds.

Galactose transport in Kluyveromyces lactis: major role of the glucose permease Hgt1.

PubMed

Baruffini, Enrico; Goffrini, Paola; Donnini, Claudia; Lodi, Tiziana

2006-12-01

In Kluyveromyces lactis, galactose transport has been thought to be mediated by the lactose permease encoded by LAC12. In fact, a lac12 mutant unable to grow on lactose did not grow on galactose either and showed low and uninducible galactose uptake activity. The existence of other galactose transport systems, at low and at high affinity, had, however, been hypothesized on the basis of galactose uptake kinetics studies. Here we confirmed the existence of a second galactose transporter and we isolated its structural gene. It turned out to be HGT1, previously identified as encoding the high-affinity glucose carrier. Analysis of galactose transporter mutants, hgt1 and lac12, and the double mutant hgt1lac12, suggested that Hgt1 was the high-affinity and Lac12 was the low-affinity galactose transporter. HGT1 expression was strongly induced by galactose and insensitive to glucose repression. This could explain the rapid adaptation to galactose observed in K. lactis after a shift from glucose to galactose medium.

Mathematical modeling of Kluyveromyces marxianus growth in solid-state fermentation using a packed-bed bioreactor.

PubMed

Mazutti, Marcio A; Zabot, Giovani; Boni, Gabriela; Skovronski, Aline; de Oliveira, Débora; Di Luccio, Marco; Rodrigues, Maria Isabel; Maugeri, Francisco; Treichel, Helen

2010-04-01

This work investigated the growth of Kluyveromyces marxianus NRRL Y-7571 in solid-state fermentation in a medium composed of sugarcane bagasse, molasses, corn steep liquor and soybean meal within a packed-bed bioreactor. Seven experimental runs were carried out to evaluate the effects of flow rate and inlet air temperature on the following microbial rates: cell mass production, total reducing sugar and oxygen consumption, carbon dioxide and ethanol production, metabolic heat and water generation. A mathematical model based on an artificial neural network was developed to predict the above-mentioned microbial rates as a function of the fermentation time, initial total reducing sugar concentration, inlet and outlet air temperatures. The results showed that the microbial rates were temperature dependent for the range 27-50 degrees C. The proposed model efficiently predicted the microbial rates, indicating that the neural network approach could be used to simulate the microbial growth in SSF.

Carboxylic acids permeases in yeast: two genes in Kluyveromyces lactis.

PubMed

Lodi, Tiziana; Fontanesi, Flavia; Ferrero, Iliana; Donnini, Claudia

2004-09-15

Two new genes KlJEN1 and KlJEN2 were identified in Kluyveromyces lactis. The deduced structure of their products is typical of membrane-bound carriers and displays high similarity to Jen1p, the monocarboxylate permease of Saccharomyces cerevisiae. Both KlJEN1 and KlJEN2 are under the control of glucose repression mediated by FOG1 and FOG2, corresponding to S. cerevisiae GAL83 and SNF1 respectively, and KlCAT8, proteins involved in glucose signalling cascade in K. lactis. KlJEN1, but not KlJEN2, is induced by lactate. KlJEN2 in contrast is expressed at high level in ethanol and succinate. The physiological characterization of null mutants showed that KlJEN1 is the functional homologue of ScJEN1, whereas KlJEN2 encodes a dicarboxylic acids transporter. In fact, KlJen1p [transporter classification (TC) number: 2.A.1.12.2.] is required for lactate uptake and therefore for growth on lactate. KlJen2p is required for succinate transport, as demonstrated by succinate uptake experiments and by inability of Kljen2 mutant to grow on succinate. This carrier appears to transport also malate and fumarate because the Kljen2 mutant cannot grow on these substrates and the succinate uptake is competed by these carboxylic acids. We conclude that KlJEN2 is the first yeast gene shown to encode a dicarboxylic acids permease.

Attraction of Coffee Bean Weevil, Araecerus fasciculatus, to Volatiles from the Industrial Yeast Kluyveromyces lactis.

PubMed

Yang, Shuai; Mei, Xiang-Dong; Zhang, Xiao-Fang; Li, Yao-Fa; She, Dongmei; Zhang, Tao; Ning, Jun

2017-02-01

The coffee bean weevil (CBW), Araecerus fasciculatus (De Geer, 1775) (Coleoptera: Anthribidae) is an important pest of stored products such as grains, coffee beans, cassava, and traditional Chinese medicine materials. In China, CBW causes large losses of Daqu, a traditional Chinese liquor fermentation starter, and, unfortunately, the use of conventional insecticides against CBW is not suitable in Daqu storage. We found CBW to be highly attracted to fermenting yeast cultures, such as Kluyveromyces lactis. Eight volatile compounds, produced by fermenting cultures and not by sterile samples, were identified by gas chromatography coupled with mass spectrometry. Five of these substances elicited significant responses in Y-tube behavioral bioassays. Field trapping experiments revealed 2-phenylethanol and 2-phenylethyl acetate to be crucial for attraction of CBW. Results show that yeast volatiles play an important role in host location, and that 2-phenylethanol and 2-phenylethyl acetate could be utilized as potential attractants in monitoring and control systems against this important pest.

Characterization of a Nucleus-Encoded Chitinase from the Yeast Kluyveromyces lactis

PubMed Central

Colussi, Paul A.; Specht, Charles A.; Taron, Christopher H.

2005-01-01

Endogenous proteins secreted from Kluyveromyces lactis were screened for their ability to bind to or to hydrolyze chitin. This analysis resulted in identification of a nucleus-encoded extracellular chitinase (KlCts1p) with a chitinolytic activity distinct from that of the plasmid-encoded killer toxin α-subunit. Sequence analysis of cloned KlCTS1 indicated that it encodes a 551-amino-acid chitinase having a secretion signal peptide, an amino-terminal family 18 chitinase catalytic domain, a serine-threonine-rich domain, and a carboxy-terminal type 2 chitin-binding domain. The association of purified KlCts1p with chitin is stable in the presence of high salt concentrations and pH 3 to 10 buffers; however, complete dissociation and release of fully active KlCts1p occur in 20 mM NaOH. Similarly, secreted human serum albumin harboring a carboxy-terminal fusion with the chitin-binding domain derived from KlCts1p also dissociates from chitin in 20 mM NaOH, demonstrating the domain's potential utility as an affinity tag for reversible chitin immobilization or purification of alkaliphilic or alkali-tolerant recombinant fusion proteins. Finally, haploid K. lactis cells harboring a cts1 null mutation are viable but exhibit a cell separation defect, suggesting that KlCts1p is required for normal cytokinesis, probably by facilitating the degradation of septum-localized chitin. PMID:15932978

Characterization of a nucleus-encoded chitinase from the yeast Kluyveromyces lactis.

PubMed

Colussi, Paul A; Specht, Charles A; Taron, Christopher H

2005-06-01

Endogenous proteins secreted from Kluyveromyces lactis were screened for their ability to bind to or to hydrolyze chitin. This analysis resulted in identification of a nucleus-encoded extracellular chitinase (KlCts1p) with a chitinolytic activity distinct from that of the plasmid-encoded killer toxin alpha-subunit. Sequence analysis of cloned KlCTS1 indicated that it encodes a 551-amino-acid chitinase having a secretion signal peptide, an amino-terminal family 18 chitinase catalytic domain, a serine-threonine-rich domain, and a carboxy-terminal type 2 chitin-binding domain. The association of purified KlCts1p with chitin is stable in the presence of high salt concentrations and pH 3 to 10 buffers; however, complete dissociation and release of fully active KlCts1p occur in 20 mM NaOH. Similarly, secreted human serum albumin harboring a carboxy-terminal fusion with the chitin-binding domain derived from KlCts1p also dissociates from chitin in 20 mM NaOH, demonstrating the domain's potential utility as an affinity tag for reversible chitin immobilization or purification of alkaliphilic or alkali-tolerant recombinant fusion proteins. Finally, haploid K. lactis cells harboring a cts1 null mutation are viable but exhibit a cell separation defect, suggesting that KlCts1p is required for normal cytokinesis, probably by facilitating the degradation of septum-localized chitin.

Ethanol production using whole plant biomass of Jerusalem artichoke by Kluyveromyces marxianus CBS1555.

PubMed

Kim, Seonghun; Park, Jang Min; Kim, Chul Ho

2013-03-01

Jerusalem artichoke is a low-requirement sugar crop containing cellulose and hemicellulose in the stalk and a high content of inulin in the tuber. However, the lignocellulosic component in Jerusalem artichoke stalk reduces the fermentability of the whole plant for efficient bioethanol production. In this study, Jerusalem artichoke stalk was pretreated sequentially with dilute acid and alkali, and then hydrolyzed enzymatically. During enzymatic hydrolysis, approximately 88 % of the glucan and xylan were converted to glucose and xylose, respectively. Batch and fed-batch simultaneous saccharification and fermentation of both pretreated stalk and tuber by Kluyveromyces marxianus CBS1555 were effectively performed, yielding 29.1 and 70.2 g/L ethanol, respectively. In fed-batch fermentation, ethanol productivity was 0.255 g ethanol per gram of dry Jerusalem artichoke biomass, or 0.361 g ethanol per gram of glucose, with a 0.924 g/L/h ethanol productivity. These results show that combining the tuber and the stalk hydrolysate is a useful strategy for whole biomass utilization in effective bioethanol fermentation from Jerusalem artichoke.

Purification and substrate specificities of a fructanase from Kluyveromyces marxianus isolated from the fermentation process of Mezcal.

PubMed

Arrizon, Javier; Morel, Sandrine; Gschaedler, Anne; Monsan, Pierre

2011-02-01

A fructanase, produced by a Kluyveromyces marxianus strain isolated during the fermentation step of the elaboration process of "Mezcal de Guerrero" was purified and biochemically characterized. The active protein was a glycosylated dimer with a molecular weight of approximately 250 kDa. The specific enzymatic activity of the protein was determined for different substrates: sucrose, inulin, Agave tequilana fructan, levan and Actilight® and compared with the activity of Fructozyme®. The hydrolysis profile of the different substrates analyzed by HPAEC-PAD showed that the enzyme has different affinities over the substrates tested with a sucrose/inulin enzymatic activity ratio (S/I) of 125. For the hydrolysis of Agave tequilana fructans, the enzyme also showed a higher enzymatic activity and specificity than Fructozyme®, which is important for its potential application in the tequila industry. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ethanol fermentation from molasses at high temperature by thermotolerant yeast Kluyveromyces sp. IIPE453 and energy assessment for recovery.

PubMed

Dasgupta, Diptarka; Ghosh, Prasenjit; Ghosh, Debashish; Suman, Sunil Kumar; Khan, Rashmi; Agrawal, Deepti; Adhikari, Dilip K

2014-10-01

High temperature ethanol fermentation from sugarcane molasses B using thermophilic Crabtree-positive yeast Kluyveromyces sp. IIPE453 was carried out in batch bioreactor system. Strain was found to have a maximum specific ethanol productivity of 0.688 g/g/h with 92 % theoretical ethanol yield. Aeration and initial sugar concentration were tuning parameters to regulate metabolic pathways of the strain for either cell mass or higher ethanol production during growth with an optimum sugar to cell ratio 33:1 requisite for fermentation. An assessment of ethanol recovery from fermentation broth via simulation study illustrated that distillation-based conventional recovery was significantly better in terms of energy efficiency and overall mass recovery in comparison to coupled solvent extraction-azeotropic distillation technique for the same.

Ploidy Variation in Kluyveromyces marxianus Separates Dairy and Non-dairy Isolates

PubMed Central

Ortiz-Merino, Raúl A.; Varela, Javier A.; Coughlan, Aisling Y.; Hoshida, Hisashi; da Silveira, Wendel B.; Wilde, Caroline; Kuijpers, Niels G. A.; Geertman, Jan-Maarten; Wolfe, Kenneth H.; Morrissey, John P.

2018-01-01

Kluyveromyces marxianus is traditionally associated with fermented dairy products, but can also be isolated from diverse non-dairy environments. Because of thermotolerance, rapid growth and other traits, many different strains are being developed for food and industrial applications but there is, as yet, little understanding of the genetic diversity or population genetics of this species. K. marxianus shows a high level of phenotypic variation but the only phenotype that has been clearly linked to a genetic polymorphism is lactose utilisation, which is controlled by variation in the LAC12 gene. The genomes of several strains have been sequenced in recent years and, in this study, we sequenced a further nine strains from different origins. Analysis of the Single Nucleotide Polymorphisms (SNPs) in 14 strains was carried out to examine genome structure and genetic diversity. SNP diversity in K. marxianus is relatively high, with up to 3% DNA sequence divergence between alleles. It was found that the isolates include haploid, diploid, and triploid strains, as shown by both SNP analysis and flow cytometry. Diploids and triploids contain long genomic tracts showing loss of heterozygosity (LOH). All six isolates from dairy environments were diploid or triploid, whereas 6 out 7 isolates from non-dairy environment were haploid. This also correlated with the presence of functional LAC12 alleles only in dairy haplotypes. The diploids were hybrids between a non-dairy and a dairy haplotype, whereas triploids included three copies of a dairy haplotype. PMID:29619042

Trichoderma sp. spores and Kluyveromyces marxianus cells magnetic separation: Immobilization on chitosan-coated magnetic nanoparticles.

PubMed

Palacios-Ponce, Sócrates; Ramos-González, Rodolfo; Ruiz, Héctor A; Aguilar, Miguel A; Martínez-Hernández, José L; Segura-Ceniceros, Elda P; Aguilar, Cristóbal N; Michelena, Georgina; Ilyina, Anna

2017-07-03

In the present study, the interactions between chitosan-coated magnetic nanoparticles (C-MNP) and Trichoderma sp. spores as well as Kluyveromyces marxianus cells were studied. By Plackett-Burman design, it was demonstrated that factors which directly influenced on yeast cell immobilization and magnetic separation were inoculum and C-MNP quantity, stirring speed, interaction time, and volume of medium, while in the case of fungal spores, the temperature also was disclosed as an influencing factor. Langmuir and Freundlich models were applied for the mathematical analysis of adsorption isotherms at 30°C. For Trichoderma sp. spore adsorption isotherm, the highest correlation coefficient was observed for lineal function of Langmuir model with a maximum adsorption capacity at 5.00E + 09 spores (C-MNP g -1 ). Adsorption isotherm of K. marxianus cells was better adjusted to Freundlich model with a constant (K f ) estimated as 2.05E + 08 cells (C-MNP g -1 ). Both systems may have a novel application in fermentation processes assisted with magnetic separation of biomass.

Metals sorption from aqueous solutions by Kluyveromyces marxianus: process optimization, equilibrium modeling and chemical characterization.

PubMed

Pal, Rama; Tewari, Saumyata; Rai, Jai P N

2009-10-01

The dead Kluyveromyces marxianus biomass, a fermentation industry waste, was used to explore its sorption potential for lead, mercury, arsenic, cobalt, and cadmium as a function of pH, biosorbent dosage, contact time, agitation speed, and initial metal concentration. The equilibrium data fitted the Langmuir model better for cobalt and cadmium, but Freundlich isotherm for all metals tested. At equilibrium, the maximum uptake capacity (Qmax) was highest for lead followed by mercury, arsenic, cobalt, and cadmium. The RL values ranged between 0-1, indicating favorable sorption of all test metals by the biosorbent. The maximum Kf value of Pb showed its efficient removal from the solution. However, multi-metal analysis depicted that sorption of all metals decreased except Pb. The potentiometric titration of biosorbent revealed the presence of functional groups viz. amines, carboxylic acids, phosphates, and sulfhydryl group involved in heavy metal sorption. The extent of contribution of functional groups and lipids to biosorption was in the order: carboxylic>lipids>amines>phosphates. Blocking of sulfhydryl group did not have any significant effect on metal sorption.

Cloning, production, and functional expression of the bacteriocin enterocin A, produced by Enterococcus faecium T136, by the yeasts Pichia pastoris, Kluyveromyces lactis, Hansenula polymorpha, and Arxula adeninivorans.

PubMed

Borrero, Juan; Kunze, Gotthard; Jiménez, Juan J; Böer, Erik; Gútiez, Loreto; Herranz, Carmen; Cintas, Luis M; Hernández, Pablo E

2012-08-01

The bacteriocin enterocin A (EntA) produced by Enterococcus faecium T136 has been successfully cloned and produced by the yeasts Pichia pastoris X-33EA, Kluyveromyces lactis GG799EA, Hansenula polymorpha KL8-1EA, and Arxula adeninivorans G1212EA. Moreover, P. pastoris X-33EA and K. lactis GG799EA produced EntA in larger amounts and with higher antimicrobial and specific antimicrobial activities than the EntA produced by E. faecium T136.

Dietary supplemental Kluyveromyces marxianus alters the serum metabolite profile in broiler chickens.

PubMed

Wang, Weiwei; Li, Zhui; Gan, Liping; Fan, Hao; Guo, Yuming

2018-06-18

Metabolomics is used to evaluate the bioavailability of food components, as well as to validate the metabolic changes associated with food consumption. This study was conducted to investigate the effects of the dietary supplement Kluyveromyces marxianus on the serum metabolite profile in broiler chickens. A total of 240 1-d-old broilers were divided into 2 groups with 8 replicates. Birds were fed basal diets without or with K. marxianus supplementation (5 × 1010 CFU kg-1 of diet). Serum samples were collected on d 21 and were analyzed by high-performance liquid chromatography with quadrupole time-of flight/mass spectrometry. The results showed that supplemental K. marxianus altered the concentrations of a variety of metabolites in the serum. Thereinto, a total of 39 metabolites were identified at higher (P < 0.05) concentrations while 21 metabolites were identified at lower (P < 0.05) concentrations in the treatment group as compared with the control. These metabolites were primarily involved with the regulation of amino acids and carbohydrate metabolism. Further metabolic pathway analysis revealed that glutamine and glutamate metabolism was the most relevant and critical pathway identified from these two groups. The activated pathway may partially interpret the beneficial effects of K. marxianus. Overall, the present research could promote our understanding of the probiotic action of K. marxianus and provide new insight into the design and application of K. marxianus-containing functional foods.

Improving xylitol production at elevated temperature with engineered Kluyveromyces marxianus through over-expressing transporters.

PubMed

Zhang, Jia; Zhang, Biao; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

2015-01-01

Three transporter genes including Kluyveromyces marxianus aquaglyceroporin gene (KmFPS1), Candida intermedia glucose/xylose facilitator gene (CiGXF1) or glucose/xylose symporter gene (CiGXS1) were over-expressed in K. marxianus YZJ017 to improve xylitol production at elevated temperatures. The xylitol production of YZJ074 that harbored CiGXF1 was improved to 147.62g/L in Erlenmeyer flask at 42°C. In fermenter, 99.29 and 149.60g/L xylitol were produced from 99.55 and 151.91g/L xylose with productivity of 4.14 and 3.40g/L/h respectively at 42°C. Even at 45°C, YZJ074 could produce 101.30g/L xylitol from 101.41g/L xylose with productivity of 2.81g/L/h. Using fed-batch fermentation through repeatedly adding non-sterilized substrate directly, YZJ074 could produce 312.05g/L xylitol which is the highest yield reported to date. The engineered strains YZJ074 which can produce xylitol at elevated temperatures is an excellent foundation for xylitol bioconversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polygalacturonase and ethanol production in Kluyveromyces marxianus: potential use of polygalacturonase in foodstuffs.

PubMed

Serrat, Manuel; Bermúdez, Rosa C; Villa, Tomás G

2004-04-01

The coproduction of ethanol and polygalacturonase (PG) in a pilot-scale batch fermentor using yeast extract--glucose (YD)--and sugar beet molasses (SBM)-based media was implemented utilizing a new high-PG-producing strain of Kluyveromyces marxianus. A certain growth inhibition was observed in SBM medium, causing ethanol and PG production to be lower. Ethanol productivity and accumulation values of 1.94 g/(L x h) and 40 g/L, respectively, were attained in YD, whereas the best fermentation efficiency (95.1%) was achieved with SBM medium. Maximal PG synthesis occurred at the end of cell growth, with values of 1.08 and 0.46 U/(mg x h) for the YD and SBM media, respectively. When the cultures reached stationary phase, PG production stopped. The highest accumulation level (17 U/mL) occurred in YD medium, in agreement with previous laboratory-scale studies carried out for this strain. The potential applications of the crude enzyme preparations were evaluated with different fruit juices and vegetable slices. The enzyme was able to increase the filtration rate of orange, pear, and apple juices by twofold. Additionally, complete clarification of apple juice was readily accomplished, whereas cucumber, carrot, and banana tissues were macerated to a lesser extent. Copyright 2004 Humana Press Inc.

Statistical investigation of Kluyveromyces lactis cells permeabilization with ethanol by response surface methodology.

PubMed

de Faria, Janaína T; Rocha, Pollyana F; Converti, Attilio; Passos, Flávia M L; Minim, Luis A; Sampaio, Fábio C

2013-12-01

The aim of our study was to select the optimal operating conditions to permeabilize Kluyveromyces lactis cells using ethanol as a solvent as an alternative to cell disruption and extraction. Cell permeabilization was carried out by a non-mechanical method consisting of chemical treatment with ethanol, and the results were expressed as β-galactosidase activity. Experiments were conducted under different conditions of ethanol concentration, treatment time and temperature according to a central composite rotatable design (CCRD), and the collected results were then worked out by response surface methodology (RSM). Cell permeabilization was improved by an increase in ethanol concentration and simultaneous decreases in the incubation temperature and treatment time. Such an approach allowed us to identify an optimal range of the independent variables within which the β-galactosidase activity was optimized. A maximum permeabilization of 2,816 mmol L(-1) oNP min(-1) g(-1) was obtained by treating cells with 75.0% v/v of ethanol at 20.0 °C for 15.0 min. The proposed methodology resulted to be effective and suited for K. lactis cells permeabilization at a lab-scale and promises to be of possible interest for future applications mainly in the food industry.

Simultaneous saccharification and fermentation of Agave tequilana fructans by Kluyveromyces marxianus yeasts for bioethanol and tequila production.

PubMed

Flores, Jose-Axel; Gschaedler, Anne; Amaya-Delgado, Lorena; Herrera-López, Enrique J; Arellano, Melchor; Arrizon, Javier

2013-10-01

Agave tequilana fructans (ATF) constitute a substrate for bioethanol and tequila industries. As Kluyveromyces marxianus produces specific fructanases for ATF hydrolysis, as well as ethanol, it can perform simultaneous saccharification and fermentation. In this work, fifteen K. marxianus yeasts were evaluated to develop inoculums with fructanase activity on ATF. These inoculums were added to an ATF medium for simultaneous saccharification and fermentation. All the yeasts, showed exo-fructanhydrolase activity with different substrate specificities. The yeast with highest fructanase activity in the inoculums showed the lowest ethanol production level (20 g/l). Five K. marxianus strains were the most suitable for the simultaneous saccharification and fermentation of ATF. The volatile compounds composition was evaluated at the end of fermentation, and a high diversity was observed between yeasts, nevertheless all of them produced high levels of isobutyl alcohol. The simultaneous saccharification and fermentation of ATF with K. marxianus strains has potential for industrial application. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fermentation of molasses using a thermotolerant yeast, Kluyveromyces marxianus IMB3: simplex optimisation of media supplements.

PubMed

Gough, S; Flynn, O; Hack, C J; Marchant, R

1996-09-01

The use of molasses as a substrate for ethanol production by the thermotolerant yeast Kluyveromyces marxianus var. marxianus was investigated at 45 degrees C. A maximum ethanol concentration of 7.4% (v/v) was produced from unsupplemented molasses at a concentration of 23% (v/v). The effect on ethanol production of increasing the sucrose concentration in 23% (v/v) molasses was determined. Increased sucrose concentration had a similar detrimental effect on the final ethanol produced as the increase in molasses concentration. This indicated that the effect may be due to increased osmotic activity as opposed to other components in the molasses. The optimum concentration of the supplements nitrogen, magnesium, potassium and fatty acid for maximum ethanol production rate was determined using the Nelder and Mead (Computer J 7:308-313, 1965) simplex optimisation method. The optimum concentration of the supplements were 0.576 g1(-1) magnesium sulphate, 0.288 g1(-1) potassium dihydrogen phosphate and 0.36% (v/v) linseed oil. Added nitrogen in the form of ammonium sulphate did not affect the ethanol production rate.

Transcriptome analysis of the thermotolerant yeast Kluyveromyces marxianus CCT 7735 under ethanol stress.

PubMed

Diniz, Raphael Hermano Santos; Villada, Juan C; Alvim, Mariana Caroline Tocantins; Vidigal, Pedro Marcus Pereira; Vieira, Nívea Moreira; Lamas-Maceiras, Mónica; Cerdán, María Esperanza; González-Siso, María-Isabel; Lahtvee, Petri-Jaan; da Silveira, Wendel Batista

2017-09-01

The thermotolerant yeast Kluyveromyces marxianus displays a potential to be used for ethanol production from both whey and lignocellulosic biomass at elevated temperatures, which is highly alluring to reduce the cost of the bioprocess. Nevertheless, contrary to Saccharomyces cerevisiae, K. marxianus cannot tolerate high ethanol concentrations. We report the transcriptional profile alterations in K. marxianus under ethanol stress in order to gain insights about mechanisms involved with ethanol response. Time-dependent changes have been characterized under the exposure of 6% ethanol and compared with the unstressed cells prior to the ethanol addition. Our results reveal that the metabolic flow through the central metabolic pathways is impaired under the applied ethanol stress. Consistent with these results, we also observe that genes involved with ribosome biogenesis are downregulated and gene-encoding heat shock proteins are upregulated. Remarkably, the expression of some gene-encoding enzymes related to unsaturated fatty acid and ergosterol biosynthesis decreases upon ethanol exposure, and free fatty acid and ergosterol measurements demonstrate that their content in K. marxianus does not change under this stress. These results are in contrast to the increase previously reported with S. cerevisiae subjected to ethanol stress and suggest that the restructuration of K. marxianus membrane composition differs in the two yeasts which gives important clues to understand the low ethanol tolerance of K. marxianus compared to S. cerevisiae.

The major facilitator superfamily transporter Knq1p modulates boron homeostasis in Kluyveromyces lactis.

PubMed

Svrbicka, Alexandra; Toth Hervay, Nora; Gbelska, Yvetta

2016-03-01

Boron is an essential micronutrient for living cells, yet its excess causes toxicity. To date, the mechanisms of boron toxicity are poorly understood. Recently, the ScATR1 gene has been identified encoding the main boron efflux pump in Saccharomyces cerevisiae. In this study, we analyzed the ScATR1 ortholog in Kluyveromyces lactis--the KNQ1 gene, to understand whether it participates in boron stress tolerance. We found that the KNQ1 gene, encoding a permease belonging to the major facilitator superfamily, is required for K. lactis boron tolerance. Deletion of the KNQ1 gene led to boron sensitivity and its overexpression increased K. lactis boron tolerance. The KNQ1 expression was induced by boron and the intracellular boron concentration was controlled by Knq1p. The KNQ1 promoter contains two putative binding motifs for the AP-1-like transcription factor KlYap1p playing a central role in oxidative stress defense. Our results indicate that the induction of the KNQ1 expression requires the presence of KlYap1p and that Knq1p like its ortholog ScAtr1p in S. cerevisiae functions as a boron efflux pump providing boron resistance in K. lactis.

Kluyveromyces wickerhamii killer toxin: purification and activity towards Brettanomyces/Dekkera yeasts in grape must.

PubMed

Comitini, Francesca; Ciani, Maurizio

2011-03-01

Brettanomyces/Dekkera yeasts have been identified as part of the grape yeast flora. They are well known for colonizing the cellar environmental and spoiling wines, causing haze, turbidity and strong off-flavours in wines and enhancing the volatile acidity. As the general practices applied to combat Brettanomyces/Dekkera yeasts are not particularly appropriate during wine ageing and storage, a biological alternative to curtailing their growth would be welcomed in winemaking. In this study, we investigated the Kluyveromyces wickerhamii killer toxin (Kwkt) that is active against Brettanomyces/Dekkera spoilage yeasts. Purification procedures allowed the identification of Kwkt as a protein with an apparent molecular mass of 72 kDa and without any glycosyl residue. Interestingly, purified Kwkt has fungicidal effects at low concentrations under the physicochemical conditions of winemaking. The addition of 40 and 80 mg L(-1) purified Kwkt showed efficient antispoilage effects, controlling both growth and metabolic activity of sensitive spoilage yeasts. At these two killer toxin concentrations, compounds known to contribute to the 'Brett' character of wines, such as ethyl phenols, were not produced. Thus, purified Kwkt appears to be a suitable biological strategy to control Brettanomyces/Dekkera yeasts during fermentation, wine ageing and storage. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Production of bioethanol from effluents of the dairy industry by Kluyveromyces marxianus.

PubMed

Zoppellari, Francesca; Bardi, Laura

2013-09-25

Whey and scotta are effluents coming from cheese and ricotta processing respectively. Whey contains minerals, lipids, lactose and proteins; scotta contains mainly lactose. Whey can be reused in several ways, such as protein extraction or animal feeding, while nowadays scotta is just considered as a waste; moreover, due to very high volumes of whey produced in the world, it poses serious environmental and disposal problems. Alternative destinations of these effluents, such as biotechnological transformations, can be a way to reach both goals of improving the added value of the agroindustrial processes and reducing their environmental impact. In this work we investigated the way to produce bioethanol from lactose of whey and scotta and to optimize the fermentation yields. Kluyveromyces marxianus var. marxianus was chosen as lactose-fermenting yeast. Batch, aerobic and anaerobic, fermentations and semicontinuous fermentations in dispersed phase and in packed bed reactor were carried out of row whey, scotta and mix 1:1 whey:scotta at a laboratory scale. Different temperatures (28-40°C) were also tested to check whether the thermotolerance of the chosen yeast could be useful to improve the ethanol yield. The best performances were reached at low temperatures (28°C); high temperatures are also compatible with good ethanol yields in whey fermentations, but not in scotta fermentations. Semicontinuous fermentations in dispersed phase gave the best fermentation performances, particularly with scotta. Then both effluents can be considered suitable for ethanol production. The good yields obtained from scotta allow us to transform this waste in a source. Copyright © 2012 Elsevier B.V. All rights reserved.

Toxicity of nalidixic acid on candida albicans, Saccharomyces cerevisiae, and Kluyveromyces lactis.

PubMed

Sobieski, R J; Brewer, A R

1976-03-01

The antibacterial drug nalidixic acid (Nal) can suppress the growth of Candida albicans at levels of the drug normally found in urine. Growth suppression increases as drug levels are increased, and Nal also causes a similar proportional inhibition of the synthesis of all cellular macromolecules. However, growth temperature (25 versus 37 C) and the divalent cations Mg(2+) and Mn(2+) can increase C. albicans resistance to Nal. Also, nitrogen depletion of Candida shows that Nal-treated and untreated cells exhibit no difference in leucine uptake during readaptation to nitrogen. In Nal-treated, nitrogen-starved cells, ribonucleic acid and deoxyribonucleic acid (DNA) biosynthesis are less affected than in unstarved Nal-treated cells, but of the two nucleic acids DNA synthesis is the most affected. Nal-resistant strains of C. albicans exhibit a slight toxicity for macromolecular synthesis. Nal treatment of a synchronized population of Saccharomyces cerevisiae results in an increase in the culture mean doubling time of, at most, 20%, but Nal causes the loss of synchronous cell division. With a synchronized population of Kluyveromyces lactis, Nal causes an increase in the mean doubling time of upwards of 300%, with synchrony of cell division being maintained. It is known that S. cerevisiae asynchronously synthesizes mitochondrial DNA during the cell cycle, whereas with K. lactis it is synchronous. Thus, with C. albicans Nal toxicity is dependent both on the dose and the physiological state of the cell. Furthermore, Nal inhibits growth of yeast with synchronous mitochondrial DNA synthesis more adversely than yeast with asynchronous mitochondrial DNA synthesis.

KNQ1, a Kluyveromyces lactis gene encoding a transmembrane protein, may be involved in iron homeostasis.

PubMed

Marchi, Emmanuela; Lodi, Tiziana; Donnini, Claudia

2007-08-01

The original purpose of the experiments described in this article was to identify, in the biotechnologically important yeast Kluyveromyces lactis, gene(s) that are potentially involved in oxidative protein folding within the endoplasmic reticulum (ER), which often represents a bottleneck for heterologous protein production. Because treatment with the membrane-permeable reducing agent dithiothreitol inhibits disulfide bond formation and mimics the reducing effect that the normal transit of folding proteins has in the ER environment, the strategy was to search for genes that conferred higher levels of resistance to dithiothreitol when present in multiple copies. We identified a gene (KNQ1) encoding a drug efflux permease for several toxic compounds that in multiple copies conferred increased dithiothreitol resistance. However, the KNQ1 product is not involved in the excretion of dithiothreitol or in recombinant protein secretion. We generated a knq1 null mutant, and showed that both overexpression and deletion of the KNQ1 gene resulted in increased resistance to dithiothreitol. KNQ1 amplification and deletion resulted in enhanced transcription of iron transport genes, suggesting, for the membrane-associated protein Knq1p, a new, unexpected role in iron homeostasis on which dithiothreitol tolerance may depend.

Improved ethanol tolerance of Saccharomyces cerevisiae in mixed cultures with Kluyveromyces lactis on high-sugar fermentation.

PubMed

Yamaoka, Chizuru; Kurita, Osamu; Kubo, Tomoko

2014-12-01

The influence of non-Saccharomyces yeast, Kluyveromyces lactis, on metabolite formation and the ethanol tolerance of Saccharomyces cerevisiae in mixed cultures was examined on synthetic minimal medium containing 20% glucose. In the late stage of fermentation after the complete death of K. lactis, S. cerevisiae in mixed cultures was more ethanol-tolerant than that in pure culture. The chronological life span of S. cerevisiae was shorter in pure culture than mixed cultures. The yeast cells of the late stationary phase both in pure and mixed cultures had a low buoyant density with no significant difference in the non-quiescence state between both cultures. In mixed cultures, the glycerol contents increased and the alanine contents decreased when compared with the pure culture of S. cerevisiae. The distinctive intracellular amino acid pool concerning its amino acid concentrations and its amino acid composition was observed in yeast cells with different ethanol tolerance in the death phase. Co-cultivation of K. lactis seems to prompt S. cerevisiae to be ethanol tolerant by forming opportune metabolites such as glycerol and alanine and/or changing the intracellular amino acid pool. Copyright © 2014 Elsevier GmbH. All rights reserved.

Comparing cell viability and ethanol fermentation of the thermotolerant yeast Kluyveromyces marxianus and Saccharomyces cerevisiae on steam-exploded biomass treated with laccase.

PubMed

Moreno, Antonio D; Ibarra, David; Ballesteros, Ignacio; González, Alberto; Ballesteros, Mercedes

2013-05-01

In this study, the thermotolerant yeast Kluyveromyces marxianus CECT 10875 was compared to the industrial strain Saccharomyces cerevisiae Ethanol Red for lignocellulosic ethanol production. For it, whole slurry from steam-exploded wheat straw was used as raw material, and two process configurations, simultaneous saccharification and fermentation (SSF) and presaccharification and simultaneous saccharification and fermentation (PSSF), were evaluated. Compared to S. cerevisiae, which was able to produce ethanol in both process configurations, K. marxianus was inhibited, and neither growth nor ethanol production occurred during the processes. However, laccase treatment of the whole slurry removed specifically lignin phenols from the overall inhibitory compounds present in the slurry and triggered the fermentation by K. marxianus, attaining final ethanol concentrations and yields comparable to those obtained by S. cerevisiae. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reaction kinetics and galactooligosaccharide product profiles of the β-galactosidases from Bacillus circulans, Kluyveromyces lactis and Aspergillus oryzae.

PubMed

Yin, Huifang; Bultema, Jelle B; Dijkhuizen, Lubbert; van Leeuwen, Sander S

2017-06-15

β-Galactosidase enzymes are used in the dairy industry to convert lactose into galactooligosaccharides (GOS) that are added to infant formula to mimic the molecular sizes and prebiotic functions of human milk oligosaccharides. Here we report a detailed analysis of the clearly different GOS profiles of the commercial β-galactosidases from Bacillus circulans, Kluyveromyces lactis and Aspergillus oryzae. Also the GOS yields of these enzymes differed, varying from 48.3% (B. circulans) to 34.9% (K. lactis), and 19.5% (A. oryzae). Their incubation with lactose plus the monosaccharides Gal or Glc resulted in altered GOS profiles. Experiments with 13 C 6 labelled Gal and Glc showed that both monosaccharides act as acceptor substrates in the transgalactosylation reactions. The data shows that the lactose isomers β-d-Galp-(1→2)-d-Glcp, β-d-Galp-(1→3)-d-Glcp and β-d-Galp-(1→6)-d-Glcp are formed from acceptor reactions with free Glc and not by rearrangement of Glc in the active site. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ethanol production from sunflower meal biomass by simultaneous saccharification and fermentation (SSF) with Kluyveromyces marxianus ATCC 36907.

PubMed

Camargo, Danielle; Gomes, Simone D; Sene, Luciane

2014-11-01

The lignocellulosic materials are considered promising renewable resources for ethanol production, but improvements in the processes should be studied to reduce operating costs. Thus, the appropriate enzyme loading for cellulose saccharification is critical for process economics. This study aimed at evaluating the concentration of cellulase and β-glucosidase in the production of bioethanol by simultaneous saccharification and fermentation (SSF) of sunflower meal biomass. The sunflower biomass was pretreated with 6% H2SO4 (w/v), at 121 °C, for 20 min, for hemicellulose removal and delignificated with 1% NaOH. SSF was performed with Kluyveromyces marxianus ATCC 36907, at 38 °C, 150 rpm, for 72 h, with different enzyme concentrations (Cellulase Complex NS22086-10, 15 and 20 FPU/gsubstrate and β-Glucosidase NS22118, with a cellulase to β-glucosidase ratio of 1.5:1; 2:1 and 3:1). The best condition for ethanol production was cellulase 20 FPU/gsubstrate and β-glucosidase 13.3 CBU/gsubstrate, resulting in 27.88 g/L ethanol, yield of 0.47 g/g and productivity of 0.38 g/L h. Under this condition the highest enzymatic conversion of cellulose to glucose was attained (87.06%).

Fermentation of cacao (Theobroma cacao L.) seeds with a hybrid Kluyveromyces marxianus strain improved product quality attributes.

PubMed

Leal, Gildemberg Amorim; Gomes, Luiz Humberto; Efraim, Priscilla; de Almeida Tavares, Flavio Cesar; Figueira, Antonio

2008-08-01

Fermentation of Theobroma cacao (cacao) seeds is an absolute requirement for the full development of chocolate flavor precursors. An adequate aeration of the fermenting cacao seed mass is a fundamental prerequisite for a satisfactory fermentation. Here, we evaluated whether a controlled inoculation of cacao seed fermentation using a Kluyveromyces marxianus hybrid yeast strain, with an increased pectinolytic activity, would improve an earlier liquid drainage ('sweatings') from the fermentation mass, developing a superior final product quality. Inoculation with K. marxianus increased by one third the volume of drained liquid and affected the microorganism population structure during fermentation, which was detectable up to the end of the process. Introduction of the hybrid yeast affected the profile of total seed protein degradation evaluated by polyacrylamide gel electrophoresis, with improved seed protein degradation, and reduction of titrable acidity. Sensorial evaluation of the chocolate obtained from beans fermented with the K. marxianus inoculation was more accepted by analysts in comparison with the one from cocoa obtained through natural fermentation. The increase in mass aeration during the first 24 h seemed to be fundamental for the improvement of fermentation quality, demonstrating the potential application of this improved hybrid yeast strain with superior exogenous pectinolytic activity.

Lignocellulosic sugar management for xylitol and ethanol fermentation with multiple cell recycling by Kluyveromyces marxianus IIPE453.

PubMed

Dasgupta, Diptarka; Ghosh, Debashish; Bandhu, Sheetal; Adhikari, Dilip K

2017-07-01

Optimum utilization of fermentable sugars from lignocellulosic biomass to deliver multiple products under biorefinery concept has been reported in this work. Alcohol fermentation has been carried out with multiple cell recycling of Kluyveromyces marxianus IIPE453. The yeast utilized xylose-rich fraction from acid and steam treated biomass for cell generation and xylitol production with an average yield of 0.315±0.01g/g while the entire glucose rich saccharified fraction had been fermented to ethanol with high productivity of 0.9±0.08g/L/h. A detailed insight into its genome illustrated the strain's complete set of genes associated with sugar transport and metabolism for high-temperature fermentation. A set flocculation proteins were identified that aided in high cell recovery in successive fermentation cycles to achieve alcohols with high productivity. We have brought biomass derived sugars, yeast cell biomass generation, and ethanol and xylitol fermentation in one platform and validated the overall material balance. 2kg sugarcane bagasse yielded 193.4g yeast cell, and with multiple times cell recycling generated 125.56g xylitol and 289.2g ethanol (366mL). Copyright © 2017 Elsevier GmbH. All rights reserved.

Partial purification and characterization of exoinulinase from Kluyveromyces marxianus YS-1 for preparation of high-fructose syrup.

PubMed

Singh, Ram Sarup; Dhaliwal, Rajesh; Puri, Munish

2007-05-01

An extracellular exoinulinase (2,1-beta-D fructan fructanohydrolase, EC 3.2.1.7), which catalyzes the hydrolysis of inulin into fructose and glucose, was purified 23.5-fold by ethanol precipitation, followed by Sephadex G-100 gel permeation from a cell-free extract of Kluyveromyces marxianus YS-1. The partially purified enzyme exhibited considerable activity between pH 5 to 6, with an optimum pH of 5.5, while it remained stable (100%) for 3 h at the optimum temperature of 50 degrees C. Mn2+ and Ca2+ produced a 2.4-fold and 1.2-fold enhancement in enzyme activity, whereas Hg2+ and Ag2+ completely inhibited the inulinase. A preparation of the partially purified enzyme effectively hydrolyzed inulin, sucrose, and raffinose, yet no activity was found with starch, lactose, and maltose. The enzyme preparation was then successfully used to hydrolyze pure inulin and raw inulin from Asparagus racemosus for the preparation of a high-fructose syrup. In a batch system, the exoinulinase hydrolyzed 84.8% of the pure inulin and 86.7% of the raw Asparagus racemosus inulin, where fructose represented 43.6 mg/ml and 41.3 mg/ml, respectively.

Protein Kinases Involved in Mating and Osmotic Stress in the Yeast Kluyveromyces lactis▿

PubMed Central

Kawasaki, Laura; Castañeda-Bueno, María; Sánchez-Paredes, Edith; Velázquez-Zavala, Nancy; Torres-Quiroz, Francisco; Ongay-Larios, Laura; Coria, Roberto

2008-01-01

Systematic disruption of genes encoding kinases and mitogen-activated protein kinases (MAPKs) was performed in Kluyveromyces lactis haploid cells. The mutated strains were assayed by their capacity to mate and to respond to hyperosmotic stress. The K. lactis Ste11p (KlSte11p) MAPK kinase kinase (MAPKKK) was found to act in both mating and osmoresponse pathways while the scaffold KlSte5p and the MAPK KlFus3p appeared to be specific for mating. The p21-activated kinase KlSte20p and the kinase KlSte50p participated in both pathways. Protein association experiments showed interaction of KlSte50p and KlSte20p with Gα and Gβ, respectively, the G protein subunits involved in the mating pathway. Both KlSte50p and KlSte20p also showed interaction with KlSte11p. Disruption mutants of the K. lactis PBS2 (KlPBS2) and KlHOG1 genes of the canonical osmotic response pathway resulted in mutations sensitive to high salt and high sorbitol but dispensable for mating. Mutations that eliminate the MAPKK KlSte7p activity had a strong effect on mating and also showed sensitivity to osmotic stress. Finally, we found evidence of physical interaction between KlSte7p and KlHog1p, in addition to diminished Hog1p phosphorylation after a hyperosmotic shock in cells lacking KlSte7p. This study reveals novel roles for components of transduction systems in yeast. PMID:18024598

Production of antioxidant and ACE-inhibitory peptides from Kluyveromyces marxianus protein hydrolysates: Purification and molecular docking.

PubMed

Mirzaei, Mahta; Mirdamadi, Saeed; Ehsani, Mohamad Reza; Aminlari, Mahmoud

2018-04-01

Kluyveromyces marxianus protein hydrolysates were prepared by two different sonicated-enzymatic (trypsin and chymotrypsin) hydrolysis treatments to obtain antioxidant and ACE-inhibitory peptides. Trypsin and chymotrypsin hydrolysates obtained by 5 h, exhibited the highest antioxidant and ACE-inhibitory activities. After fractionation using ultrafiltration and reverse phase high performance liquid chromatography (RP-HPLC) techniques, two new peptides were identified. One fragment (LL-9, MW = 1180 Da) with the amino acid sequence of Leu-Pro-Glu-Ser-Val-His-Leu-Asp-Lys showed significant ACE inhibitory activity (IC 50  = 22.88 μM) while another peptide fragment (VL-9, MW = 1118 Da) with the amino acid sequence of Val-Leu-Ser-Thr-Ser-Phe-Pro-Pro-Lys showed the highest antioxidant and ACE inhibitory properties (IC 50  = 15.20 μM, 5568 μM TE/mg protein). The molecular docking studies revealed that the ACE inhibitory activities of VL-9 is due to interaction with the S2 (His513, His353, Glu281) and S'1 (Glu162) pockets of ACE and LL-9 can fit perfectly into the S1 (Thr345) and S2 (Tyr520, Lys511, Gln281) pockets of ACE. Copyright © 2017. Published by Elsevier B.V.

Enhanced production of extracellular inulinase by the yeast Kluyveromyces marxianus in xylose catabolic state.

PubMed

Hoshida, Hisashi; Kidera, Kenta; Takishita, Ryuta; Fujioka, Nobuhisa; Fukagawa, Taiki; Akada, Rinji

2018-06-01

The production of extracellular proteins by the thermotolerant yeast Kluyveromyces marxianus, which utilizes various sugars, was investigated using media containing sugars such as glucose, galactose, and xylose. SDS-PAGE analysis of culture supernatants revealed abundant production of an extracellular protein when cells were grown in xylose medium. The N-terminal sequence of the extracellular protein was identical to a part of the inulinase encoded by INU1 in the genome. Inulinase is an enzyme hydrolyzing β-2,1-fructosyl bond in inulin and sucrose and is not required for xylose assimilation. Disruption of INU1 in the strain DMKU 3-1042 lost the production of the extracellular protein and resulted in growth defect in sucrose and inulin media, indicating that the extracellular protein was inulinase (sucrase). In addition, six K. marxianus strains among the 16 strains that were analyzed produced more inulinase in xylose medium than in glucose medium. However, expression analysis indicated that the INU1 promoter activity was lower in the xylose medium than in the glucose medium, suggesting that enhanced production of inulinase is controlled in a post-transcriptional manner. The production of inulinase was also higher in cultures with more agitation, suggesting that oxygen supply affects the production of inulinase. Taken together, these results suggest that both xylose and oxygen supply shift cellular metabolism to enhance the production of extracellular inulinase. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Evaluation of Kluyveromyces marxianus FII 510700 grown on a lactose-based medium as a source of a natural bioemulsifier.

PubMed

Lukondeh, Tredwell; Ashbolt, Nicholas J; Rogers, Peter L

2003-12-01

Mannoprotein with emulsification properties was extracted from the cell walls of Kluyveromyces marxianus grown on a lactose-based medium by autoclaving cells in a citrate buffer at pH 7. The purified product was evaluated for chemical and physical stability to establish its potential use as a natural emulsifier in processed foods. The yield of purified bioemulsifier from this strain of K. marxianus was 4-7% of the original dry cell weight. The purified product, at a concentration of 12 g l(-1), formed emulsions that were stable for 3 months when subjected to a range of pH (3-11) and NaCl concentrations (2-50 g l(-1)). The composition of this mannoprotein was 90% carbohydrate (mannan) and 4-6% protein. These values are similar to mannoprotein extracted from cells of Saccharomyces cerevisiae, which is the traditional source. Consequently K. marxianus cultivated on a low-cost lactose-based medium such as whey, a lactose-rich clean waste of the dairy industry, could be developed as a source of bioemulsifier for use in the food industry.

The modeling of ethanol production by Kluyveromyces marxianus using whey as substrate in continuous A-Stat bioreactors.

PubMed

Gabardo, Sabrina; Pereira, Gabriela Feix; Rech, Rosane; Ayub, Marco Antônio Záchia

2015-09-01

We investigated the kinetics of whey bioconversion into ethanol by Kluyveromyces marxianus in continuous bioreactors using the "accelerostat technique" (A-stat). Cultivations using free and Ca-alginate immobilized cells were evaluated using two different acceleration rates (a). The kinetic profiles of these systems were modeled using four different unstructured models, differing in the expressions for the specific growth (μ) and substrate consumption rates (r s), taking into account substrate limitation and product inhibition. Experimental data showed that the dilution rate (D) directly affected cell physiology and metabolism. The specific growth rate followed the dilution rate (μ≈D) for the lowest acceleration rate (a = 0.0015 h(-2)), condition in which the highest ethanol yield (0.52 g g(-1)) was obtained. The highest acceleration rate (a = 0.00667 h(-2)) led to a lower ethanol yield (0.40 g g(-1)) in the system where free cells were used, whereas with immobilized cells ethanol yields increased by 23 % (0.49 g g(-1)). Among the evaluated models, Monod and Levenspiel combined with Ghose and Tyagi models were found to be more appropriate for describing the kinetics of whey bioconversion into ethanol. These results may be useful in scaling up the process for ethanol production from whey.

Synthetic signal sequences that enable efficient secretory protein production in the yeast Kluyveromyces marxianus.

PubMed

Yarimizu, Tohru; Nakamura, Mikiko; Hoshida, Hisashi; Akada, Rinji

2015-02-14

Targeting of cellular proteins to the extracellular environment is directed by a secretory signal sequence located at the N-terminus of a secretory protein. These signal sequences usually contain an N-terminal basic amino acid followed by a stretch containing hydrophobic residues, although no consensus signal sequence has been identified. In this study, simple modeling of signal sequences was attempted using Gaussia princeps secretory luciferase (GLuc) in the yeast Kluyveromyces marxianus, which allowed comprehensive recombinant gene construction to substitute synthetic signal sequences. Mutational analysis of the GLuc signal sequence revealed that the GLuc hydrophobic peptide length was lower limit for effective secretion and that the N-terminal basic residue was indispensable. Deletion of the 16th Glu caused enhanced levels of secreted protein, suggesting that this hydrophilic residue defined the boundary of a hydrophobic peptide stretch. Consequently, we redesigned this domain as a repeat of a single hydrophobic amino acid between the N-terminal Lys and C-terminal Glu. Stretches consisting of Phe, Leu, Ile, or Met were effective for secretion but the number of residues affected secretory activity. A stretch containing sixteen consecutive methionine residues (M16) showed the highest activity; the M16 sequence was therefore utilized for the secretory production of human leukemia inhibitory factor protein in yeast, resulting in enhanced secreted protein yield. We present a new concept for the provision of secretory signal sequence ability in the yeast K. marxianus, determined by the number of residues of a single hydrophobic residue located between N-terminal basic and C-terminal acidic amino acid boundaries.

Production, purification, and characterization of a polygalacturonase from a new strain of Kluyveromyces marxianus isolated from coffee wet-processing wastewater.

PubMed

Serrat, Manuel; Bermúdez, Rose Catalina; Villa, Tomás Gonzáles

2002-03-01

A new high polygalacturonase (PG)-producing Kluyveromyces marxianus strain was isolated from coffee wet-processing wastewater. PG production in this strain is not repressed in the presence of 100 g/L of glucose and, being growth-associated, reached its maximum accumulation in the culture medium at the beginning of the stationary phase. Oxygen and galacturonic acid negatively regulated enzyme synthesis, and glucose as the carbon source afforded better enzyme yields than lactose. The data reported here show that this strain exhibits the highest index of PG production among the wild-type strains reported so far (18.8 U/mL). PG was readily purified by ion-exchange chromatography on SP-Sepharose FF. The activity corresponded to a single protein with an M(r) of 41.7kDa according to sodium dodecyl sulfatepolyacrylamide gel electrophoresis. The enzyme was stable in the pH range of 3.0-5.0 and displayed an optimal temperature of 55 degrees C; it showed a typical endosplitting way of substrate hydrolysis and exhibited a fair degree of activity on pectin with a high degree of esterification.

Opuntia ficus-indica cladodes as feedstock for ethanol production by Kluyveromyces marxianus and Saccharomyces cerevisiae.

PubMed

Kuloyo, Olukayode O; du Preez, James C; García-Aparicio, Maria del Prado; Kilian, Stephanus G; Steyn, Laurinda; Görgens, Johann

2014-12-01

The feasibility of ethanol production using an enzymatic hydrolysate of pretreated cladodes of Opuntia ficus-indica (prickly pear cactus) as carbohydrate feedstock was investigated, including a comprehensive chemical analysis of the cladode biomass and the effects of limited aeration on the fermentation profiles and sugar utilization. The low xylose and negligible mannose content of the cladode biomass used in this study suggested that the hemicellulose structure of the O. ficus-indica cladode was atypical of hardwood or softwood hemicelluloses. Separate hydrolysis and fermentation and simultaneous saccharification and fermentation procedures using Kluyveromyces marxianus and Saccharomyces cerevisiae at 40 and 35 °C, respectively, gave similar ethanol yields under non-aerated conditions. In oxygen-limited cultures K. marxianus exhibited almost double the ethanol productivity compared to non-aerated cultures, although after sugar depletion utilization of the produced ethanol was evident. Ethanol concentrations of up to 19.5 and 20.6 g l(-1) were obtained with K. marxianus and S. cerevisiae, respectively, representing 66 and 70 % of the theoretical yield on total sugars in the hydrolysate. Because of the low xylan content of the cladode biomass, a yeast capable of xylose fermentation might not be a prerequisite for ethanol production. K. marxianus, therefore, has potential as an alternative to S. cerevisiae for bioethanol production. However, the relatively low concentration of fermentable sugars in the O. ficus-indica cladode hydrolysate presents a technical constraint for commercial exploitation.

Recombination Can Cause Telomere Elongations as Well as Truncations Deep within Telomeres in Wild-Type Kluyveromyces lactis Cells ▿

PubMed Central

Bechard, Laura H.; Jamieson, Nathan; McEachern, Michael J.

2011-01-01

In this study, we examined the role of recombination at the telomeres of the yeast Kluyveromyces lactis. We demonstrated that an abnormally long and mutationally tagged telomere was subject to high rates of telomere rapid deletion (TRD) that preferentially truncated the telomere to near-wild-type size. Unlike the case in Saccharomyces cerevisiae, however, there was not a great increase in TRD in meiosis. About half of mitotic TRD events were associated with deep turnover of telomeric repeats, suggesting that telomeres were often cleaved to well below normal length prior to being reextended by telomerase. Despite its high rate of TRD, the long telomere showed no increase in the rate of subtelomeric gene conversion, a highly sensitive test of telomere dysfunction. We also showed that the long telomere was subject to appreciable rates of becoming elongated substantially further through a recombinational mechanism that added additional tagged repeats. Finally, we showed that the deep turnover that occurs within normal-length telomeres was diminished in the absence of RAD52. Taken together, our results suggest that homologous recombination is a significant process acting on both abnormally long and normally sized telomeres in K. lactis. PMID:21148753

Saccharomyces cerevisiae and Kluyveromyces marxianus Cocultures Allow Reduction of Fermentable Oligo-, Di-, and Monosaccharides and Polyols Levels in Whole Wheat Bread.

PubMed

Struyf, Nore; Laurent, Jitka; Verspreet, Joran; Verstrepen, Kevin J; Courtin, Christophe M

2017-10-04

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are small molecules that are poorly absorbed in the small intestine and rapidly fermented in the large intestine. There is evidence that a diet low in FODMAPs reduces abdominal symptoms in approximately 70% of the patients suffering from irritable bowel syndrome. Wheat contains relatively high fructan levels and is therefore a major source of FODMAPs in our diet. In this study, a yeast-based strategy was developed to reduce FODMAP levels in (whole wheat) bread. Fermentation of dough with an inulinase-secreting Kluyveromyces marxianus strain allowed to reduce fructan levels in the final product by more than 90%, while only 56%  reduction was achieved when a control Saccharomyces cerevisiae strain was used. To ensure sufficient CO 2 production, cocultures of S. cerevisiae and K. marxianus were prepared. Bread prepared with a coculture of K. marxianus and S. cerevisiae had fructan levels ≤0.2% dm, and a loaf volume comparable with that of control bread. Therefore, this approach is suitable to effectively reduce FODMAP levels in bread.

Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

PubMed

Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

2016-09-01

Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus.

PubMed

Akanni, Gabriel B; du Preez, James C; Steyn, Laurinda; Kilian, Stephanus G

2015-03-30

The cladodes of Opuntia ficus-indica (prickly pear cactus) have a low protein content; for use as a balanced feed, supplementation with other protein sources is therefore desirable. We investigated protein enrichment by cultivation of the yeasts Candida utilis and Kluyveromyces marxianus in an enzymatic hydrolysate of the cladode biomass. Dilute acid pretreatment and enzymatic hydrolysis of sun-dried cladodes resulted in a hydrolysate containing (per litre) 45.5 g glucose, 6.3 g xylose, 9.1 g galactose, 10.8 g arabinose and 9.6 g fructose. Even though K. marxianus had a much higher growth rate and utilized l-arabinose and d-galactose more completely than C. utilis, its biomass yield coefficient was lower due to ethanol and ethyl acetate production despite aerobic cultivation. Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains. This K. marxianus strain was weakly Crabtree positive. Despite its low biomass yield, its performance compared well with C. utilis. This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025.

PubMed

Rocha, Maria Valderez Ponte; Rodrigues, Tigressa Helena Soares; Melo, Vania M M; Gonçalves, Luciana R B; de Macedo, Gorete Ribeiro

2011-08-01

The potential of cashew apple bagasse as a source of sugars for ethanol production by Kluyveromyces marxianus CE025 was evaluated in this work. This strain was preliminarily cultivated in a synthetic medium containing glucose and xylose and was able to produce ethanol and xylitol at pH 4.5. Next, cashew apple bagasse hydrolysate (CABH) was prepared by a diluted sulfuric acid pretreatment and used as fermentation media. This hydrolysate is rich in glucose, xylose, and arabinose and contains traces of formic acid and acetic acid. In batch fermentations of CABH at pH 4.5, the strain produced only ethanol. The effects of temperature on the kinetic parameters of ethanol fermentation by K. marxianus CE025 using CABH were also evaluated. Maximum specific growth rate (μ(max)), overall yields of ethanol based on glucose consumption [Formula: see text] and based on glucose + xylose consumption (Y ( P/S )), overall yield of ethanol based on biomass (Y ( P/X )), and ethanol productivity (P (E)) were determined as a function of temperature. Best results of ethanol production were achieved at 30°C, which is also quite close to the optimum temperature for the formation of biomass. The process yielded 12.36 ± 0.06 g l(-1) of ethanol with a volumetric production rate of 0.257 ± 0.002 g l(-1) h(-1) and an ethanol yield of 0.417 ± 0.003 g g(-1) glucose.

Deletion of the Glucose-6-Phosphate Dehydrogenase Gene KlZWF1 Affects both Fermentative and Respiratory Metabolism in Kluyveromyces lactis▿

PubMed Central

Saliola, Michele; Scappucci, Gina; De Maria, Ilaria; Lodi, Tiziana; Mancini, Patrizia; Falcone, Claudio

2007-01-01

In Kluyveromyces lactis, the pentose phosphate pathway is an alternative route for the dissimilation of glucose. The first enzyme of the pathway is the glucose-6-phosphate dehydrogenase (G6PDH), encoded by KlZWF1. We isolated this gene and examined its role. Like ZWF1 of Saccharomyces cerevisiae, KlZWF1 was constitutively expressed, and its deletion led to increased sensitivity to hydrogen peroxide on glucose, but unlike the case for S. cerevisiae, the Klzwf1Δ strain had a reduced biomass yield on fermentative carbon sources as well as on lactate and glycerol. In addition, the reduced yield on glucose was associated with low ethanol production and decreased oxygen consumption, indicating that this gene is required for both fermentation and respiration. On ethanol, however, the mutant showed an increased biomass yield. Moreover, on this substrate, wild-type cells showed an additional band of activity that might correspond to a dimeric form of G6PDH. The partial dimerization of the G6PDH tetramer on ethanol suggested the production of an NADPH excess that was negative for biomass yield. PMID:17085636

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

PubMed Central

Saliola, Michele; Bartoccioni, Paola Chiara; De Maria, Ilaria; Lodi, Tiziana; Falcone, Claudio

2004-01-01

We have isolated a Kluyveromyces lactis mutant unable to grow on all respiratory carbon sources with the exception of lactate. Functional complementation of this mutant led to the isolation of KlSDH1, the gene encoding the flavoprotein subunit of the succinate dehydrogenase (SDH) complex, which is essential for the aerobic utilization of carbon sources. Despite the high sequence conservation of the SDH genes in Saccharomyces cerevisiae and K. lactis, they do not have the same relevance in the metabolism of the two yeasts. In fact, unlike SDH1, KlSDH1 was highly expressed under both fermentative and nonfermentative conditions. In addition to this, but in contrast with S. cerevisiae, K. lactis strains lacking KlSDH1 were still able to grow in the presence of lactate. In these mutants, oxygen consumption was one-eighth that of the wild type in the presence of lactate and was normal with glucose and ethanol, indicating that the respiratory chain was fully functional. Northern analysis suggested that alternative pathway(s), which involves pyruvate decarboxylase and the glyoxylate cycle, could overcome the absence of SDH and allow (i) lactate utilization and (ii) the accumulation of succinate instead of ethanol during growth on glucose. PMID:15189981

Efficient secretory expression of the sweet-tasting protein brazzein in the yeast Kluyveromyces lactis.

PubMed

Jo, Hyun-Joo; Noh, Jin-Seok; Kong, Kwang-Hoon

2013-08-01

Brazzein is an intensely sweet-tasting protein with high water solubility, heat stability, and taste properties resembling those of carbohydrate sweeteners. In the present study, we describe the expression of the synthetic gene encoding brazzein, a sweet protein in the yeast Kluyveromyces lactis. The synthetic brazzein gene was designed based on the biased codons of the yeast, so as to optimize its expression, as well as on the extracellular secretion for expression in an active, soluble form. The synthesized brazzein gene was cloned into the secretion vector pKLAC2, which contains the yeast prepropeptide signal from the Saccharomycescerevisiae α-mating factor. The constructed plasmid pKLAC2-des-pE1M-brazzein was introduced into the yeast K. lactis GG799. The yeast transformants were cultured for high-yield secretion of the recombinant des-pE1M-brazzein in YPGal medium for 96 h at 30°C. The expressed recombinant des-pE1M-brazzein was purified by CM-Sepharose column chromatography and approximately 104 mg/L was obtained. The purity and conformational state of the recombinant des-pE1M-brazzein were confirmed using SDS-PAGE, HPLC, and circular dichroism. The identity of the recombinant protein was also confirmed by N-terminal amino acid analysis and taste testing. The purified recombinant des-pE1M-brazzein had an intrinsic sweetness in its minor form, approximately 2130 times sweeter than sucrose on a weight basis. These results demonstrate that the K. lactis expression system is useful for producing the recombinant brazzein in active form at a high yield with attributes useful in the food industry. Copyright © 2013 Elsevier Inc. All rights reserved.

Thermotolerant Kluyveromyces marxianus and Saccharomyces cerevisiae strains representing potentials for bioethanol production from Jerusalem artichoke by consolidated bioprocessing.

PubMed

Hu, Nan; Yuan, Bo; Sun, Juan; Wang, Shi-An; Li, Fu-Li

2012-09-01

Thermotolerant inulin-utilizing yeast strains are desirable for ethanol production from Jerusalem artichoke tubers by consolidated bioprocessing (CBP). To obtain such strains, 21 naturally occurring yeast strains isolated by using an enrichment method and 65 previously isolated Saccharomyces cerevisiae strains were investigated in inulin utilization, extracellular inulinase activity, and ethanol fermentation from inulin and Jerusalem artichoke tuber flour at 40 °C. The strains Kluyveromyces marxianus PT-1 (CGMCC AS2.4515) and S. cerevisiae JZ1C (CGMCC AS2.3878) presented the highest extracellular inulinase activity and ethanol yield in this study. The highest ethanol concentration in Jerusalem artichoke tuber flour fermentation (200 g L(-1)) at 40 °C achieved by K. marxianus PT-1 and S. cerevisiae JZ1C was 73.6 and 65.2 g L(-1), which corresponded to the theoretical ethanol yield of 90.0 and 79.7 %, respectively. In the range of 30 to 40 °C, temperature did not have a significant effect on ethanol production for both strains. This study displayed the distinctive superiority of K. marxianus PT-1 and S. cerevisiae JZ1C in the thermotolerance and utilization of inulin-type oligosaccharides reserved in Jerusalem artichoke tubers. It is proposed that both K. marxianus and S. cerevisiae have considerable potential in ethanol production from Jerusalem artichoke tubers by a high temperature CBP.

Immobilization of β-galactosidase from Kluyveromyces lactis onto polymeric membrane surfaces: effect of surface characteristics.

PubMed

Güleç, Hacı Ali

2013-04-01

The aim of this study was to investigate the effects of surface characteristics of plain and plasma modified cellulose acetate (CA) membranes on the immobilization yield of β-galactosidases from Kluyveromyces lactis (KLG) and its galacto-oligosaccharide (GOS) yield, respectively. Low pressure plasma treatments involving oxygen plasma activation, plasma polymerization (PlsP) of ethylenediamine (EDA) and PlsP of 2-mercaptoethanol were used to modify plain CA membrane surfaces. KLG enzyme was immobilized onto plain and oxygen plasma treated membrane surfaces by simple adsorption. Oxygen plasma activation increased the hydrophylicity of CA membrane surfaces and it improved the immobilization yield of the enzyme by 42%. KLG enzyme was also immobilized onto CA membrane surfaces through amino groups created by PlsP of EDA via covalent binding. Plasma action at 60W plasma power and 15 min. exposure time improved the amount of membrane bounded enzyme by 3.5-fold. The enrichment of the amount of amino groups via polyethyleneimine (PEI) addition enhanced this increase from 3.5-fold to 4.5-fold. Although high enzyme loading was achived (65-83%), both of the methods dramatically decreased the enzyme activity (11-12%) and GOS yield due to probably negative effects of active amino groups. KLG enzyme was more effectively immobilized onto thiolated CA membrane surface created by PlsP of 2-mercaptoethanol with high immobilization yield (70%) and especially high enzyme activity (46%). Immobilized enzymes on the CA membranes treated by PlsP were successively reutilized for 5-8 cycles at 25°C and enzymatic derivatives retained approximately 75-80% of their initial activites at the end of the reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

Respiratory capacity of the Kluyveromyces marxianus yeast isolated from the mezcal process during oxidative stress.

PubMed

Arellano-Plaza, Melchor; Gschaedler-Mathis, Anne; Noriega-Cisneros, Ruth; Clemente-Guerrero, Mónica; Manzo-Ávalos, Salvador; González-Hernández, Juan Carlos; Saavedra-Molina, Alfredo

2013-07-01

During the mezcal fermentation process, yeasts are affected by several stresses that can affect their fermentation capability. These stresses, such as thermal shock, ethanol, osmotic and growth inhibitors are common during fermentation. Cells have improved metabolic systems and they express stress response genes in order to decrease the damage caused during the stress, but to the best of our knowledge, there are no published works exploring the effect of oxidants and prooxidants, such as H2O2 and menadione, during growth. In this article, we describe the behavior of Kluyveromyces marxianus isolated from spontaneous mezcal fermentation during oxidative stress, and compared it with that of Saccharomyces cerevisiae strains that were also obtained from mezcal, using the W303-1A strain as a reference. S. cerevisiae strains showed greater viability after oxidative stress compared with K. marxianus strains. However, when the yeast strains were grown in the presence of oxidants in the media, K. marxianus exhibited a greater ability to grow in menadione than it did in H2O2. Moreover, when K. marxianus SLP1 was grown in a minibioreactor, its behavior when exposed to menadione was different from its behavior with H2O2. The yeast maintained the ability to consume dissolved oxygen during the 4 h subsequent to the addition of menadione, and then stopped respiration. When exposed to H2O2, the yeast stopped consuming oxygen for the following 8 h, but began to consume oxygen when stressors were no longer applied. In conclusion, yeast isolated from spontaneous mezcal fermentation was able to resist oxidative stress for a long period of time.

Protein enrichment of an Opuntia ficus-indica cladode hydrolysate by cultivation of Candida utilis and Kluyveromyces marxianus

PubMed Central

Akanni, Gabriel B; du Preez, James C; Steyn, Laurinda; Kilian, Stephanus G

2015-01-01

BACKGROUND The cladodes of Opuntia ficus-indica (prickly pear cactus) have a low protein content; for use as a balanced feed, supplementation with other protein sources is therefore desirable. We investigated protein enrichment by cultivation of the yeasts Candida utilis and Kluyveromyces marxianus in an enzymatic hydrolysate of the cladode biomass. RESULTS Dilute acid pretreatment and enzymatic hydrolysis of sun-dried cladodes resulted in a hydrolysate containing (per litre) 45.5 g glucose, 6.3 g xylose, 9.1 g galactose, 10.8 g arabinose and 9.6 g fructose. Even though K. marxianus had a much higher growth rate and utilized l-arabinose and d-galactose more completely than C. utilis, its biomass yield coefficient was lower due to ethanol and ethyl acetate production despite aerobic cultivation. Yeast cultivation more than doubled the protein content of the hydrolysate, with an essential amino acid profile superior to sorghum and millet grains. CONCLUSIONS This K. marxianus strain was weakly Crabtree positive. Despite its low biomass yield, its performance compared well with C. utilis. This is the first report showing that the protein content and quality of O. ficus-indica cladode biomass could substantially be improved by yeast cultivation, including a comparative evaluation of C. utilis and K. marxianus. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25371280

Improved bioethanol production in an engineered Kluyveromyces lactis strain shifted from respiratory to fermentative metabolism by deletion of NDI1

PubMed Central

González-Siso, María Isabel; Touriño, Alba; Vizoso, Ángel; Pereira-Rodríguez, Ángel; Rodríguez-Belmonte, Esther; Becerra, Manuel; Cerdán, María Esperanza

2015-01-01

In this paper, we report the metabolic engineering of the respiratory yeast Kluyveromyces lactis by construction and characterization of a null mutant (Δklndi1) in the single gene encoding a mitochondrial alternative internal dehydrogenase. Isolated mitochondria of the Δklndi1 mutant show unaffected rate of oxidation of exogenous NADH, but no oxidation of matrix NADH; this confirms that KlNdi1p is the only internal NADH dehydrogenase in K. lactis mitochondria. Permeabilized cells of the Δklndi1 mutant do not show oxidation of matrix NADH, which suggests that shuttle systems to transfer the NADH from mitochondrial matrix to cytosol, for being oxidized by external dehydrogenases, are not functional. The Δklndi1 mutation decreases the chronological life span in absence of nutrients. The expression of KlNDI1 is increased by glutathione reductase depletion. The Δklndi1 mutation shifts the K. lactis metabolism from respiratory to fermentative: the Δklndi1 strain shows reduced respiration rate and increased ethanol production from glucose, while it does not grow in non-fermentable carbon sources such as lactate. The biotechnological benefit of the Δklndi1 mutant for bioethanol production from waste cheese whey lactose was proved. PMID:25186243

Direct fermentation of Jerusalem artichoke tuber powder for production of l-lactic acid and d-lactic acid by metabolically engineered Kluyveromyces marxianus.

PubMed

Bae, Jung-Hoon; Kim, Hyun-Jin; Kim, Mi-Jin; Sung, Bong Hyun; Jeon, Jae-Heung; Kim, Hyun-Soon; Jin, Yong-Su; Kweon, Dae-Hyuk; Sohn, Jung-Hoon

2018-01-20

An efficient production system for optically pure l- and d-lactic acid (LA) from Jerusalem artichoke tuber powder (JAP) was developed by metabolic engineering of Kluyveromyces marxianus. To construct LA-producing strains, the ethanol fermentation pathway of K. marxianus was redirected to LA production by disruption of KmPDC1 and expression of l- and d-lactate dehydrogenase (LDH) genes derived from Lactobacillus plantarum under the control of the K. marxianus translation elongation factor 1α promoter. To further increase the LA titer, the l-LA and d-LA consumption pathway of host strains was blocked by deletion of the oxidative LDH genes KmCYB2 and KmDLD1. The recombinant strains produced 130g/L l-LA and 122g/L d-LA by direct fermentation from 230g/L JAP containing 140g/L inulin, without pretreatment or nutrient supplementation. The conversion efficiency and optical purity were ≫>95% and ≫>99%, respectively. This system using JAP and the inulin-assimilating yeast K. marxianus could lead to a cost-effective process for the production of LA. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential application of aqueous two-phase systems and three-phase partitioning for the recovery of superoxide dismutase from a clarified homogenate of Kluyveromyces marxianus.

PubMed

Simental-Martínez, Jesús; Rito-Palomares, Marco; Benavides, Jorge

2014-01-01

Superoxide dismutase (SOD; EC 1.15.1.1) is an antioxidant enzyme that represents the primary cellular defense against superoxide radicals and has interesting applications in the medical and cosmetic industries. In the present work, the partition behavior of SOD in aqueous two-phase systems (ATPS) (using a standard solution and a complex extract from Kluyveromyces marxianus as sample) was characterized on different types of ATPS (polymer-polymer, polymer-salt, alcohol-salt, and ionic liquid (IL)-salt). The systems composed of PEG 3350-potassium phosphate, 45% TLL, 0.5 M NaCl (315 U/mg, 87% recovery, and 15.1-fold purification) and t-butanol-20% ammonium sulfate (205.8 U/mg, 80% recovery and 9.8-fold purification), coupled with a subsequent 100 kDa ultrafiltration stage, allowed the design of a prototype process for the recovery and partial purification of the product of interest. The findings reported herein demonstrate the potential of PEG-salt ATPS for the potential recovery of SOD. © 2014 American Institute of Chemical Engineers.

Rational mutagenesis by engineering disulphide bonds improves Kluyveromyces lactis beta-galactosidase for high-temperature industrial applications

PubMed Central

Rico-Díaz, Agustín; Álvarez-Cao, María-Efigenia; Escuder-Rodríguez, Juan-José; González-Siso, María-Isabel; Cerdán, M. Esperanza; Becerra, Manuel

2017-01-01

Kluyveromyces lactis β-galactosidase (Kl-β-Gal) is one of the most important enzymes in the dairy industry. The poor stability of this enzyme limits its use in the synthesis of galactooligosaccharides (GOS) and other applications requiring high operational temperature. To obtain thermoresistant variants, a rational mutagenesis strategy by introducing disulphide bonds in the interface between the enzyme subunits was used. Two improved mutants, R116C/T270C and R116C/T270C/G818C, had increased half-lives at 45 °C compared to Kl-β-Gal (2.2 and 6.8 fold increases, respectively). Likewise, Tm values of R116C/T270C and R116C/T270C/G818C were 2.4 and 8.5 °C, respectively, higher than Kl-β-Gal Tm. Enrichment in enzymatically active oligomeric forms in these mutant variants also increased their catalytic efficiency, due to the reinforcement of the interface contacts. In this way, using an artificial substrate (p-nitrophenyl-β-D-galactopyranoside), the Vmax values of the mutants were ~1.4 (R116C/T270C) and 2 (R116C/T270C/G818C) fold higher than that of native Kl-β-Gal. Using the natural substrate (lactose) the Vmax for R116C/T270C/G818C almost doubled the Vmax for Kl-β-Gal. Validation of these mutant variants of the enzyme for their use in applications that depend on prolonged incubations at high temperatures was achieved at the laboratory scale by monitoring their catalytic activity in GOS synthesis. PMID:28361909

Non-homologous end joining-mediated functional marker selection for DNA cloning in the yeast Kluyveromyces marxianus.

PubMed

Hoshida, Hisashi; Murakami, Nobutada; Suzuki, Ayako; Tamura, Ryoko; Asakawa, Jun; Abdel-Banat, Babiker M A; Nonklang, Sanom; Nakamura, Mikiko; Akada, Rinji

2014-01-01

The cloning of DNA fragments into vectors or host genomes has traditionally been performed using Escherichia coli with restriction enzymes and DNA ligase or homologous recombination-based reactions. We report here a novel DNA cloning method that does not require DNA end processing or homologous recombination, but that ensures highly accurate cloning. The method exploits the efficient non-homologous end-joining (NHEJ) activity of the yeast Kluyveromyces marxianus and consists of a novel functional marker selection system. First, to demonstrate the applicability of NHEJ to DNA cloning, a C-terminal-truncated non-functional ura3 selection marker and the truncated region were PCR-amplified separately, mixed and directly used for the transformation. URA3(+) transformants appeared on the selection plates, indicating that the two DNA fragments were correctly joined by NHEJ to generate a functional URA3 gene that had inserted into the yeast chromosome. To develop the cloning system, the shortest URA3 C-terminal encoding sequence that could restore the function of a truncated non-functional ura3 was determined by deletion analysis, and was included in the primers to amplify target DNAs for cloning. Transformation with PCR-amplified target DNAs and C-terminal truncated ura3 produced numerous transformant colonies, in which a functional URA3 gene was generated and was integrated into the chromosome with the target DNAs. Several K. marxianus circular plasmids with different selection markers were also developed for NHEJ-based cloning and recombinant DNA construction. The one-step DNA cloning method developed here is a relatively simple and reliable procedure among the DNA cloning systems developed to date. Copyright © 2013 John Wiley & Sons, Ltd.

Rational mutagenesis by engineering disulphide bonds improves Kluyveromyces lactis beta-galactosidase for high-temperature industrial applications.

PubMed

Rico-Díaz, Agustín; Álvarez-Cao, María-Efigenia; Escuder-Rodríguez, Juan-José; González-Siso, María-Isabel; Cerdán, M Esperanza; Becerra, Manuel

2017-03-31

Kluyveromyces lactis β-galactosidase (Kl-β-Gal) is one of the most important enzymes in the dairy industry. The poor stability of this enzyme limits its use in the synthesis of galactooligosaccharides (GOS) and other applications requiring high operational temperature. To obtain thermoresistant variants, a rational mutagenesis strategy by introducing disulphide bonds in the interface between the enzyme subunits was used. Two improved mutants, R116C/T270C and R116C/T270C/G818C, had increased half-lives at 45 °C compared to Kl-β-Gal (2.2 and 6.8 fold increases, respectively). Likewise, Tm values of R116C/T270C and R116C/T270C/G818C were 2.4 and 8.5 °C, respectively, higher than Kl-β-Gal Tm. Enrichment in enzymatically active oligomeric forms in these mutant variants also increased their catalytic efficiency, due to the reinforcement of the interface contacts. In this way, using an artificial substrate (p-nitrophenyl-β-D-galactopyranoside), the Vmax values of the mutants were ~1.4 (R116C/T270C) and 2 (R116C/T270C/G818C) fold higher than that of native Kl-β-Gal. Using the natural substrate (lactose) the Vmax for R116C/T270C/G818C almost doubled the Vmax for Kl-β-Gal. Validation of these mutant variants of the enzyme for their use in applications that depend on prolonged incubations at high temperatures was achieved at the laboratory scale by monitoring their catalytic activity in GOS synthesis.

Growth and ethanol fermentation ability on hexose and pentose sugars and glucose effect under various conditions in thermotolerant yeast Kluyveromyces marxianus.

PubMed

Rodrussamee, Nadchanok; Lertwattanasakul, Noppon; Hirata, Katsushi; Suprayogi; Limtong, Savitree; Kosaka, Tomoyuki; Yamada, Mamoru

2011-05-01

Ethanol fermentation ability of the thermotolerant yeast Kluyveromyces marxianus, which is able to utilize various sugars including glucose, mannose, galactose, xylose, and arabinose, was examined under shaking and static conditions at high temperatures. The yeast was found to produce ethanol from all of these sugars except for arabinose under a shaking condition but only from hexose sugars under a static condition. Growth and sugar utilization rate under a static condition were slower than those under a shaking condition, but maximum ethanol yield was slightly higher. Even at 40°C, a level of ethanol production similar to that at 30°C was observed except for galactose under a static condition. Glucose repression on utilization of other sugars was observed, and it was more evident at elevated temperatures. Consistent results were obtained by the addition of 2-deoxyglucose. The glucose effect was further examined at a transcription level, and it was found that KmGAL1 for galactokinase and KmXYL1 for xylose reductase for galactose and xylose/arabinose utilization, respectively, were repressed by glucose at low and high temperatures, but KmHXK2 for hexokinase was not repressed. We discuss the possible mechanism of glucose repression and the potential for utilization of K. marxianus in high-temperature fermentation with mixed sugars containing glucose.

Molecular cloning of the plasma membrane H(+)-ATPase from Kluyveromyces lactis: a single nucleotide substitution in the gene confers ethidium bromide resistance and deficiency in K+ uptake.

PubMed Central

Miranda, M; Ramírez, J; Peña, A; Coria, R

1995-01-01

A Kluyveromyces lactis strain resistant to ethidium bromide and deficient in potassium uptake was isolated. Studies on the proton-pumping activity of the mutant strain showed that a decreased H(+)-ATPase specific activity was responsible for the observed phenotypes. The putative K. lactis PMA1 gene encoding the plasma membrane H(+)-ATPase was cloned by its ability to relieve the potassium transport defect of this mutant and by reversing its resistance to ethidium bromide. Its deduced amino acid sequence predicts a protein 899 residues long that is structurally colinear in its full length to H(+)-ATPases cloned from different yeasts, except for the presence of a variable N-terminal domain. By PCR-mediated amplification, we identified a transition from G to A that rendered the substitution of the fully conserved methionine at position 699 by isoleucine. We attribute to this amino acid change the low capacity of the mutant H(+)-ATPase to pump out protons. PMID:7730265

Bioethanol production from sodium hydroxide/hydrogen peroxide-pretreated water hyacinth via simultaneous saccharification and fermentation with a newly isolated thermotolerant Kluyveromyces marxianu strain.

PubMed

Yan, Jinping; Wei, Zhilei; Wang, Qiaoping; He, Manman; Li, Shumei; Irbis, Chagan

2015-10-01

In this study, bioethanol production from NaOH/H2O2-pretreated water hyacinth was investigated. Pretreatment of water hyacinth with 1.5% (v/v) H2O2 and 3% (w/v) NaOH at 25 °C increased the production of reducing sugars (223.53 mg/g dry) and decreased the cellulose crystallinity (12.18%), compared with 48.67 mg/g dry and 22.80% in the untreated sample, respectively. The newly isolated Kluyveromyces marxianu K213 showed greater ethanol production from glucose (0.43 g/g glucose) at 45 °C than did the control Saccharomyces cerevisiae angel yeast. The maximum ethanol concentration (7.34 g/L) achieved with K. marxianu K213 by simultaneous saccharification and fermentation (SSF) from pretreated water hyacinth at 42 °C was 1.78-fold greater than that produced by angel yeast S. cerevisiae at 30 °C. The present work demonstrates that bioethanol production achieved via SSF of NaOH/H2O2-pretreated water hyacinth with K. marxianu K213 is a promising strategy to utilize water hyacinth biomass. Copyright © 2015. Published by Elsevier Ltd.

Molecular analysis of UAS(E), a cis element containing stress response elements responsible for ethanol induction of the KlADH4 gene of Kluyveromyces lactis.

PubMed

Mazzoni, C; Santori, F; Saliola, M; Falcone, C

2000-01-01

KlADH4 is a gene of Kluyveromyces lactis encoding a mitochondrial alcohol dehydrogenase activity, which is specifically induced by ethanol and insensitive to glucose repression. In this work, we report the molecular analysis of UAS(E), an element of the KlADH4 promoter which is essential for the induction of KlADH4 in the presence of ethanol. UAS(E) contains five stress response elements (STREs), which have been found in many genes of Saccharomyces cerevisiae involved in the response of cells to conditions of stress. Whereas KlADH4 is not responsive to stress conditions, the STREs present in UAS(E) seem to play a key role in the induction of the gene by ethanol, a situation that has not been observed in the related yeast S. cerevisiae. Gel retardation experiments showed that STREs in the KlADH4 promoter can bind factor(s) under non-inducing conditions. Moreover, we observed that the RAP1 binding site present in UAS(E) binds KlRap1p.

Ethanol fermentation with Kluyveromyces marxianus from Jerusalem artichoke grown in salina and irrigated with a mixture of seawater and freshwater.

PubMed

Yuan, W J; Zhao, X Q; Ge, X M; Bai, F W

2008-12-01

To study fuel ethanol fermentation with Kluyveromyces marxianus ATCC8554 from Jerusalem artichoke (Helianthus tuberosus) grown in salina and irrigated with a mixture of seawater and freshwater. The growth and ethanol fermentation of K. marxianus ATCC8554 were studied using inulin as substrate. The activity of inulinase, which attributes to the hydrolysis of inulin, the main carbohydrate in Jerusalem artichoke, was monitored. The optimum temperatures were 38 degrees C for growth and inulinase production, and 35 degrees C for ethanol fermentation. Aeration was not necessary for ethanol fermentation with the K. marxianus from inulin. Then, the fresh Jerusalem artichoke tubers grown in salina and irrigated with 25% and 50% seawater were further examined for ethanol fermentation with the K. marxianus, and a higher ethanol yield was achieved for the Jerusalem artichoke tuber irrigated with 25% seawater. Furthermore, the dry meal of the Jerusalem artichoke tubers irrigated with 25% seawater was examined for ethanol fermentation at three solid concentrations of 200, 225 and 250 g l(-1), and the highest ethanol yield of 0.467, or 91.5% of the theoretical value of 0.511, was achieved for the slurry with a solid concentration of 200 g l(-1). Halophilic Jerusalem artichoke can be used for fuel ethanol production. Halophilic Jerusalem artichoke, not competing with grain crops for arable land, is a sustainable feedstock for fuel ethanol production.

Influence of carbon and nitrogen source on production of volatile fragrance and flavour metabolites by the yeast Kluyveromyces marxianus.

PubMed

Gethins, Loughlin; Guneser, Onur; Demirkol, Aslı; Rea, Mary C; Stanton, Catherine; Ross, R Paul; Yuceer, Yonca; Morrissey, John P

2015-01-01

The yeast Kluyveromyces marxianus produces a range of volatile molecules with applications as fragrances or flavours. The purpose of this study was to establish how nutritional conditions influence the production of these metabolites. Four strains were grown on synthetic media, using a variety of carbon and nitrogen sources and volatile metabolites analysed using gas chromatography-mass spectrometry (GC-MS). The nitrogen source had pronounced effects on metabolite production: levels of the fusel alcohols 2-phenylethanol and isoamyl alcohol were highest when yeast extract was the nitrogen source, and ammonium had a strong repressing effect on production of 2-phenylethyl acetate. In contrast, the nitrogen source did not affect production of isoamyl acetate or ethyl acetate, indicating that more than one alcohol acetyl transferase activity is present in K. marxianus. Production of all acetate esters was low when cells were growing on lactose (as opposed to glucose or fructose), with a lower intracellular pool of acetyl CoA being one explanation for this observation. Bioinformatic and phylogenetic analysis of the known yeast alcohol acetyl transferases ATF1 and ATF2 suggests that the ancestral protein Atf2p may not be involved in synthesis of volatile acetate esters in K. marxianus, and raises interesting questions as to what other genes encode this activity in non-Saccharomyces yeasts. Identification of all the genes involved in ester synthesis will be important for development of the K. marxianus platform for flavour and fragrance production. Copyright © 2014 John Wiley & Sons, Ltd.

Comparison of a pectinolytic extract of Kluyveromyces marxianus and a commercial enzyme preparation in the production of Ives (Vitis labrusca) grape juice.

PubMed

Piemolini-Barreto, Luciani Tatsch; Antônio, Regina Vasconcellos; Echeverrigaray, Sergio

2015-05-01

This study analyses the effect of the crude enzymatic extract produced by Kluyveromyces marxianus (EEB) in the maceration and clarification of juice produced from Ives (Vitis labrusca) grapes compared to the commercial enzyme preparation Pectinex(®)Ultra Color (PEC). Treatments were conducted with a total pectinolytic activity of 1 U/mL of fruit juice, at 40 °C, for 60 min. After the enzymatic treatment, the juices were evaluated with respect to yield, viscosity, and degree of clarification, as well as the effect of the enzymes on polyphenol concentration, anthocyanins, and juice color. The results showed that both EEB and PEC increase yield, reduce viscosity and contribute to the clarification of grape juice. After enzyme treatment with the EEB preparation, the extraction yield increased 28.02 % and decreased 50.70 % in viscosity during the maceration of the pulp. During the juice production process clarification increased 11.91 %. With PEC, higher values for these parameters: 42.36, 63.20, and 26.81 % respectively, were achieved. The addition of EEB resulted in grape juice with better color intensity and extraction of phenolic compounds and anthocyanins. Considering all comparison criteria, the enzymatic extract of K. marxianus NRRL-Y-7571 can potentially be used in the production of juice.

Growth, ethanol production, and inulinase activity on various inulin substrates by mutant Kluyveromyces marxianus strains NRRL Y-50798 and NRRL Y-50799.

PubMed

Galindo-Leva, Luz Ángela; Hughes, Stephen R; López-Núñez, Juan Carlos; Jarodsky, Joshua M; Erickson, Adam; Lindquist, Mitchell R; Cox, Elby J; Bischoff, Kenneth M; Hoecker, Eric C; Liu, Siqing; Qureshi, Nasib; Jones, Marjorie A

2016-07-01

Economically important plants contain large amounts of inulin. Disposal of waste resulting from their processing presents environmental issues. Finding microorganisms capable of converting inulin waste to biofuel and valuable co-products at the processing site would have significant economic and environmental impact. We evaluated the ability of two mutant strains of Kluyveromyces marxianus (Km7 and Km8) to utilize inulin for ethanol production. In glucose medium, both strains consumed all glucose and produced 0.40 g ethanol/g glucose at 24 h. In inulin medium, Km7 exhibited maximum colony forming units (CFU)/mL and produced 0.35 g ethanol/g inulin at 24 h, while Km8 showed maximum CFU/mL and produced 0.02 g ethanol/g inulin at 96 h. At 24 h in inulin + glucose medium, Km7 produced 0.40 g ethanol/g (inulin + glucose) and Km8 produced 0.20 g ethanol/g (inulin + glucose) with maximum CFU/mL for Km8 at 72 h, 40 % of that for Km7 at 36 h. Extracellular inulinase activity at 6 h for both Km7 and Km8 was 3.7 International Units (IU)/mL.

Sequential application of waste whey as a medium component for Kluyveromyces lactis cultivation and a co-feeder for lipase immobilization by CLEA method.

PubMed

Veteikytė, Aušra; Šiekštelė, Rimantas; Tvaska, Bronius; Matijošytė, Inga

2017-05-01

Currently, much attention is paid to technologies which can be drivers of the circular economy across different sectors, in particular, to develop technologies for utilization or reusability of biocompatible materials from industrial waste. One of such is the milk whey, which is a cheap biobased raw material, the disposal of which is a major problem for the dairy industry. Our proposed and investigated technology is based on a continuous exploitation of the whey combining microbiology and biotechnology. Primarily, whey was used as a nutrition source for the cultivation of Kluyveromyces lactis with the aim to produce the targeted biocatalyst-lipase. During cultivation, the whey was transformed into the hydrolyzed form, which was further successfully applied as a protein feeder (external linker) for immobilization of lipase by cross-linked enzyme aggregate (CLEA) method. The first time use of whey as a co-feeder for immobilization of enzymes by CLEA method has shown promising results and increased the stability of lipases for temperature and organic solvents. Hydrolysis of rapeseed oil catalyzed with immobilized derivatives was obtained with 45-96% efficiency at non-optimized conditions. Additionally, the determined kinetic parameters indicated that the rate of p-nitrophenyl palmitate hydrolysis was not changed drastically after immobilization.

Direct fermentation of raw starch using a Kluyveromyces marxianus strain that expresses glucoamylase and alpha-amylase to produce ethanol.

PubMed

Wang, Rongliang; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

2014-01-01

Raw starch and raw cassava tuber powder were directly and efficiently fermented at elevated temperatures to produce ethanol using the thermotolerant yeast Kluyveromyces marxianus that expresses α-amylase from Aspergillus oryzae as well as α-amylase and glucoamylase from Debaryomyces occidentalis. Among the constructed K. marxianus strains, YRL 009 had the highest efficiency in direct starch fermentation. Raw starch from corn, potato, cassava, or wheat can be fermented at temperatures higher than 40°C. At the optimal fermentation temperature 42°C, YRL 009 produced 66.52 g/L ethanol from 200 g/L cassava starch, which was the highest production among the selected raw starches. This production increased to 79.75 g/L ethanol with a 78.3% theoretical yield (with all cassava starch were consumed) from raw cassava starch at higher initial cell densities. Fermentation was also carried out at 45 and 48°C. By using 200 g/L raw cassava starch, 137.11 and 87.71 g/L sugar were consumed with 55.36 and 32.16 g/L ethanol produced, respectively. Furthermore, this strain could directly ferment 200 g/L nonsterile raw cassava tuber powder (containing 178.52 g/L cassava starch) without additional nutritional supplements to produce 69.73 g/L ethanol by consuming 166.07 g/L sugar at 42°C. YRL 009, which has consolidated bioprocessing ability, is the best strain for fermenting starches at elevated temperatures that has been reported to date. © 2014 American Institute of Chemical Engineers.

Portable exhausters POR-004 SKID B, POR-005 SKID C, POR-006 SKID D storage plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, O.D.

1997-09-04

This document provides a storage plan for portable exhausters POR-004 SKID B, POR-005 SKID C, AND POR-006 SKID D. The exhausters will be stored until they are needed by the TWRS (Tank Waste Remediation Systems) Saltwell Pumping Program. The storage plan provides criteria for portable exhauster storage, periodic inspections during storage, and retrieval from storage.

Influencing cocoa flavour using Pichia kluyveri and Kluyveromyces marxianus in a defined mixed starter culture for cocoa fermentation.

PubMed

Crafack, Michael; Mikkelsen, Morten B; Saerens, Sofie; Knudsen, Morten; Blennow, Andreas; Lowor, Samuel; Takrama, Jemmy; Swiegers, Jan H; Petersen, Gert B; Heimdal, Hanne; Nielsen, Dennis S

2013-10-01

The potential impact of aromatic and pectinolytic yeasts on cocoa flavour was investigated using two defined mixed starter cultures encompassing strains of Pichia kluyveri and Kluyveromyces marxianus for inoculating cocoa beans in small scale tray fermentations. Samples for microbial and metabolite analysis were collected at 12-24 hour intervals during 120 h of fermentation. Yeast isolates were grouped by (GTG)5-based rep-PCR fingerprinting and identified by sequencing of the D1/D2 region of the 26S rRNA gene and the actin gene. Pulsed Field Gel Electrophoresis (PFGE) was conducted on isolates belonging to the species P. kluyveri and K. marxianus to verify strain level identity with the inoculated strains. Furthermore, Denaturing Gradient Gel Electrophoresis (DGGE) was performed to follow yeast and bacterial dynamics over time including the presence of the bacterial inoculum consisting of Lactobacillus fermentum and Acetobacter pasteurianus. Yeast cell counts peaked after 12 h of fermentation with the predominant species being identified as Hanseniaspora opuntiae and Hanseniaspora thailandica. P. kluyveri and K. marxianus were found to compose 9.3% and 13.5% of the yeast population, respectively, after 12 h of fermentation whilst PFGE showed that ~88% of all P. kluyveri isolates and 100% of all K. marxianus isolates were identical to the inoculated strains. Despite never being the dominant yeast species at any stage of fermentation, the un-conched chocolates produced from the two inoculated fermentations were judged by sensory analysis to differ in flavour profile compared to the spontaneously fermented control. This could indicate that yeasts have a greater impact on the sensory qualities of cocoa than previously assumed. © 2013.

Simultaneous fermentation of glucose and xylose at elevated temperatures co-produces ethanol and xylitol through overexpression of a xylose-specific transporter in engineered Kluyveromyces marxianus.

PubMed

Zhang, Biao; Zhang, Jia; Wang, Dongmei; Han, Ruixiang; Ding, Rui; Gao, Xiaolian; Sun, Lianhong; Hong, Jiong

2016-09-01

Engineered Kluyveromyces marxianus strains were constructed through over-expression of various transporters for simultaneous co-fermentation of glucose and xylose. The glucose was converted into ethanol, whereas xylose was converted into xylitol which has higher value than ethanol. Over-expressing xylose-specific transporter ScGAL2-N376F mutant enabled yeast to co-ferment glucose and xylose and the co-fermentation ability was obviously improved through increasing ScGAL2-N376F expression. The production of glycerol was blocked and acetate production was reduced by disrupting gene KmGPD1. The obtained K. marxianus YZJ119 utilized 120g/L glucose and 60g/L xylose simultaneously and produced 50.10g/L ethanol and 55.88g/L xylitol at 42°C. The yield of xylitol from consumed xylose was over 98% (0.99g/g). Through simultaneous saccharification and co-fermentation at 42°C, YZJ119 produced a maximal concentration of 44.58g/L ethanol and 32.03g/L xylitol or 29.82g/L ethanol and 31.72g/L xylitol, respectively, from detoxified or non-detoxified diluted acid pretreated corncob. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving the Organoleptic Properties of a Craft Mezcal Beverage by Increasing Fatty Acid Ethyl Ester Contents through ATF1 Expression in an Engineered Kluyveromyces marxianus UMPe-1 Yeast.

PubMed

Campos-García, Jesús; Vargas, Alejandra; Farías-Rosales, Lorena; Miranda, Ana L; Meza-Carmen, Víctor; Díaz-Pérez, Alma L

2018-05-02

Mezcal, a traditional beverage that originated in Mexico, is produced from species of the Agavaceae family. The esters associated with the yeasts utilized during fermentation are important for improving the organoleptic properties of the beverage. We improved the ester contents in a mezcal beverage by using the yeast Kluyveromyces marxianus, which was engineered with the ATF1 gene. ATF1 expression in the recombinant yeast significantly increased compared with that in the parental yeast, but its fermentative parameters were unchanged. Volatile-organic-compound-content analysis showed that esters had significantly increased in the mezcal produced with the engineered yeast. In a sensory-panel test, 48% of the panelists preferred the mezcal produced from the engineered yeast, 30% preferred the mezcal produced from the wild type, and 15 and 7% preferred the two mezcal types produced following the routine procedure. Correlation analysis showed that the fruitiness/sweetness description of the mezcal produced using the ATF1-engineered K. marxianus yeast correlated with the content of the esters, whose presence improved the organoleptic properties of the craft mezcal beverage.

Regulation of glycolysis in Kluyveromyces lactis: role of KlGCR1 and KlGCR2 in glucose uptake and catabolism.

PubMed

Neil, H; Lemaire, M; Wésolowski-Louvel, M

2004-03-01

In Kluyveromyces lactis, the casein kinase I (Rag8p) regulates the transcription of glycolytic genes and the expression of the low-affinity glucose transporter gene RAG1. This control involves the transcription factor Sck1p, a homologue of Sgc1p of Saccharomyces cerevisiae. SGC1 is known to interact genetically with ScGCR1 and ScGCR2, which code for regulators of glycolytic gene expression. Therefore, we studied the role of KlGCR1 and KlGCR2 genes in K. lactis. The Klgcr1 null mutant could not grow on glucose when respiration was blocked by antimycin A (Rag(- )phenotype). In contrast, the Klgcr2 null mutant could grow under the same conditions, although at a reduced rate. In both mutants, the transcription of glycolytic genes was affected, while that of ribosomal protein genes was not modified. Furthermore, the transcription of the glucose permease genes was also found to be affected in the two mutants, although dissimilarly. While RAG1 transcription decreased at high glucose concentrations, the expression of the high-affinity glucose permease gene HGT1 was unexpectedly impaired under gluconeogenic conditions, in the absence of glucose. Gel mobility shift assays performed with purified maltose-binding protein-KlGcr1p showed that KlGcr1p could interact directly with the promoters of the glycolytic genes, but not with the promoters of the glucose permease genes. Thus, the control exerted by KlGcr1p and KlGcr2p upon glucose transporter genes is probably indirect.

Effect of oxygenation and temperature on glucose-xylose fermentation in Kluyveromyces marxianus CBS712 strain

PubMed Central

2014-01-01

Background The yeast Kluyveromyces marxianus features specific traits that render it attractive for industrial applications. These include production of ethanol which, together with thermotolerance and the ability to grow with a high specific growth rate on a wide range of substrates, could make it an alternative to Saccharomyces cerevisiae as an ethanol producer. However, its ability to co-ferment C5 and C6 sugars under oxygen-limited conditions is far from being fully characterized. Results In the present study, K. marxianus CBS712 strain was cultivated in defined medium with glucose and xylose as carbon source. Ethanol fermentation and sugar consumption of CBS712 were investigated under different oxygen supplies (1.75%, 11.00% and 20.95% of O2) and different temperatures (30°C and 41°C). By decreasing oxygen supply, independently from the temperature, both biomass production as well as sugar utilization rate were progressively reduced. In all the tested conditions xylose consumption followed glucose exhaustion. Therefore, xylose metabolism was mainly affected by oxygen depletion. Loss in cell viability cannot explain the decrease in sugar consumption rates, as demonstrated by single cell analyses, while cofactor imbalance is commonly considered as the main cause of impairment of the xylose reductase (KmXR) - xylitol dehydrogenase (KmXDH) pathway. Remarkably, when these enzyme activities were assayed in vitro, a significant decrease was observed together with oxygen depletion, not ascribed to reduced transcription of the corresponding genes. Conclusions In the present study both oxygen supply and temperature were shown to be key parameters affecting the fermentation capability of sugars in the K. marxianus CBS712 strain. In particular, a direct correlation was observed between the decreased efficiency to consume xylose with the reduced specific activity of the two main enzymes (KmXR and KmXDH) involved in its catabolism. These data suggest that, in addition to

Effect of oxygenation and temperature on glucose-xylose fermentation in Kluyveromyces marxianus CBS712 strain.

PubMed

Signori, Lorenzo; Passolunghi, Simone; Ruohonen, Laura; Porro, Danilo; Branduardi, Paola

2014-04-08

The yeast Kluyveromyces marxianus features specific traits that render it attractive for industrial applications. These include production of ethanol which, together with thermotolerance and the ability to grow with a high specific growth rate on a wide range of substrates, could make it an alternative to Saccharomyces cerevisiae as an ethanol producer. However, its ability to co-ferment C5 and C6 sugars under oxygen-limited conditions is far from being fully characterized. In the present study, K. marxianus CBS712 strain was cultivated in defined medium with glucose and xylose as carbon source. Ethanol fermentation and sugar consumption of CBS712 were investigated under different oxygen supplies (1.75%, 11.00% and 20.95% of O2) and different temperatures (30°C and 41°C). By decreasing oxygen supply, independently from the temperature, both biomass production as well as sugar utilization rate were progressively reduced. In all the tested conditions xylose consumption followed glucose exhaustion. Therefore, xylose metabolism was mainly affected by oxygen depletion. Loss in cell viability cannot explain the decrease in sugar consumption rates, as demonstrated by single cell analyses, while cofactor imbalance is commonly considered as the main cause of impairment of the xylose reductase (KmXR) - xylitol dehydrogenase (KmXDH) pathway. Remarkably, when these enzyme activities were assayed in vitro, a significant decrease was observed together with oxygen depletion, not ascribed to reduced transcription of the corresponding genes. In the present study both oxygen supply and temperature were shown to be key parameters affecting the fermentation capability of sugars in the K. marxianus CBS712 strain. In particular, a direct correlation was observed between the decreased efficiency to consume xylose with the reduced specific activity of the two main enzymes (KmXR and KmXDH) involved in its catabolism. These data suggest that, in addition to the impairment of the

Developing a xylanase XYNZG from Plectosphaerella cucumerina for baking by heterologously expressed in Kluyveromyces lactis.

PubMed

Zhan, Fei Xiang; Wang, Qin Hong; Jiang, Si Jing; Zhou, Yu Ling; Zhang, Gui Min; Ma, Yan He

2014-12-16

Xylanase can replace chemical additives to improve the volume and sensory properties of bread in the baking. Suitable baking xylanase with improved yield will promote the application of xylanase in baking industry. The xylanase XYNZG from the Plectosphaerella cucumerina has been previously characterized by heterologous expression in Pichia pastoris. However, P. pastoris is not a suitable host for xylanase to be used in the baking process since P. pastoris does not have GRAS (Generally Regarded As Safe) status and requires large methanol supplement during the fermentation in most conditions, which is not allowed to be used in the food industry. Kluyveromyces lactis, as another yeast expression host, has a GRAS status, which has been successfully used in food and feed applications. No previous work has been reported concerning the heterologous expression of xylanase gene xynZG in K. lactis with an aim for application in baking. The xylanase gene xynZG from the P. cucumerina was heterologously expressed in K. lactis. The recombinant protein XYNZG in K. lactis presented an approximately 19 kDa band on SDS-PAGE and zymograms analysis. Transformant with the highest halo on the plate containing the RBB-xylan (Remazol Brilliant Blue-xylan) was selected for the flask fermentation in different media. The results indicated that the highest activity of 115 U/ml at 72 h was obtained with the YLPU medium. The mass spectrometry analysis suggested that the hydrolytic products of xylan by XYNZG were mainly xylobiose and xylotriose. The results of baking trials indicated that the addition of XYNZG could reduce the kneading time of dough, increase the volume of bread, improve the texture, and have more positive effects on the sensory properties of bread. Xylanase XYNZG is successfully expressed in K. lactis, which exhibits the highest activity among the published reports of the xylanase expression in K. lactis. The recombinant XYNZG can be used to improve the volume and sensory

Identification of auxotrophic mutants of the yeast Kluyveromyces marxianus by non-homologous end joining-mediated integrative transformation with genes from Saccharomyces cerevisiae.

PubMed

Yarimizu, Tohru; Nonklang, Sanom; Nakamura, Junpei; Tokuda, Shuya; Nakagawa, Takaaki; Lorreungsil, Sasithorn; Sutthikhumpha, Surasit; Pukahuta, Charida; Kitagawa, Takao; Nakamura, Mikiko; Cha-Aim, Kamonchai; Limtong, Savitree; Hoshida, Hisashi; Akada, Rinji

2013-12-01

The isolation and application of auxotrophic mutants for gene manipulations, such as genetic transformation, mating selection and tetrad analysis, form the basis of yeast genetics. For the development of these genetic methods in the thermotolerant fermentative yeast Kluyveromyces marxianus, we isolated a series of auxotrophic mutants with defects in amino acid or nucleic acid metabolism. To identify the mutated genes, linear DNA fragments of nutrient biosynthetic pathway genes were amplified from Saccharomyces cerevisiae chromosomal DNA and used to directly transform the K. marxianus auxotrophic mutants by random integration into chromosomes through non-homologous end joining (NHEJ). The appearance of transformant colonies indicated that the specific S. cerevisiae gene complemented the K. marxianus mutant. Using this interspecific complementation approach with linear PCR-amplified DNA, we identified auxotrophic mutations of ADE2, ADE5,7, ADE6, HIS2, HIS3, HIS4, HIS5, HIS6, HIS7, LYS1, LYS2, LYS4, LYS9, LEU1, LEU2, MET2, MET6, MET17, TRP3, TRP4 and TRP5 without the labour-intensive requirement of plasmid construction. Mating, sporulation and tetrad analysis techniques for K. marxianus were also established. With the identified auxotrophic mutant strains and S. cerevisiae genes as selective markers, NHEJ-mediated integrative transformation with PCR-amplified DNA is an attractive system for facilitating genetic analyses in the yeast K. marxianus. Copyright © 2013 John Wiley & Sons, Ltd.

Consolidated bioprocessing strategy for ethanol production from Jerusalem artichoke tubers by Kluyveromyces marxianus under high gravity conditions.

PubMed

Yuan, W J; Chang, B L; Ren, J G; Liu, J P; Bai, F W; Li, Y Y

2012-01-01

Developing an innovative process for ethanol fermentation from Jerusalem artichoke tubers under very high gravity (VHG) conditions. A consolidated bioprocessing (CBP) strategy that integrated inulinase production, saccharification of inulin contained in Jerusalem artichoke tubers and ethanol production from sugars released from inulin by the enzyme was developed with the inulinase-producing yeast Kluyveromyces marxianus Y179 and fed-batch operation. The impact of inoculum age, aeration, the supplementation of pectinase and nutrients on the ethanol fermentation performance of the CBP system was studied. Although inulinase activities increased with the extension of the seed incubation time, its contribution to ethanol production was negligible because vigorously growing yeast cells harvested earlier carried out ethanol fermentation more efficiently. Thus, the overnight incubation that has been practised in ethanol production from starch-based feedstocks is recommended. Aeration facilitated the fermentation process, but compromised ethanol yield because of the negative Crabtree effect of the species, and increases the risk of contamination under industrial conditions. Therefore, nonaeration conditions are preferred for the CBP system. Pectinase supplementation reduced viscosity of the fermentation broth and improved ethanol production performance, particularly under high gravity conditions, but the enzyme cost should be carefully balanced. Medium optimization was performed, and ethanol concentration as high as 94·2 g l(-1) was achieved when 0·15 g l(-1) K(2) HPO(4) was supplemented, which presents a significant progress in ethanol production from Jerusalem artichoke tubers. A CBP system using K. marxianus is suitable for efficient ethanol production from Jerusalem artichoke tubers under VHG conditions. Jerusalem artichoke tubers are an alternative to grain-based feedstocks for ethanol production. The high ethanol concentration achieved using K. marxianus with the

Kluyveromyces marxianus and Saccharomyces boulardii Induce Distinct Levels of Dendritic Cell Cytokine Secretion and Significantly Different T Cell Responses In Vitro

PubMed Central

Smith, Ida M.; Baker, Adam; Christensen, Jeffrey E.; Boekhout, Teun; Frøkiær, Hanne; Arneborg, Nils; Jespersen, Lene

2016-01-01

Interactions between members of the intestinal microbiota and the mucosal immune system can significantly impact human health, and in this context, fungi and food-related yeasts are known to influence intestinal inflammation through direct interactions with specialized immune cells in vivo. The aim of the present study was to characterize the immune modulating properties of the food-related yeast Kluyveromyces marxianus in terms of adaptive immune responses indicating inflammation versus tolerance and to explore the mechanisms behind the observed responses. Benchmarking against a Saccharomyces boulardii strain with probiotic effects documented in clinical trials, we evaluated the ability of K. marxianus to modulate human dendritic cell (DC) function in vitro. Further, we assessed yeast induced DC modulation of naive T cells toward effector responses dominated by secretion of IFNγ and IL-17 versus induction of a Treg response characterized by robust IL-10 secretion. In addition, we blocked relevant DC surface receptors and investigated the stimulating properties of β-glucan containing yeast cell wall extracts. K. marxianus and S. boulardii induced distinct levels of DC cytokine secretion, primarily driven by Dectin-1 recognition of β-glucan components in their cell walls. Upon co-incubation of yeast exposed DCs and naive T cells, S. boulardii induced a potent IFNγ response indicating TH1 mobilization. In contrast, K. marxianus induced a response dominated by Foxp3+ Treg cells, a characteristic that may benefit human health in conditions characterized by excessive inflammation and positions K. marxianus as a strong candidate for further development as a novel yeast probiotic. PMID:27898740

Kluyveromyces marxianus and Saccharomyces boulardii Induce Distinct Levels of Dendritic Cell Cytokine Secretion and Significantly Different T Cell Responses In Vitro.

PubMed

Smith, Ida M; Baker, Adam; Christensen, Jeffrey E; Boekhout, Teun; Frøkiær, Hanne; Arneborg, Nils; Jespersen, Lene

2016-01-01

Interactions between members of the intestinal microbiota and the mucosal immune system can significantly impact human health, and in this context, fungi and food-related yeasts are known to influence intestinal inflammation through direct interactions with specialized immune cells in vivo. The aim of the present study was to characterize the immune modulating properties of the food-related yeast Kluyveromyces marxianus in terms of adaptive immune responses indicating inflammation versus tolerance and to explore the mechanisms behind the observed responses. Benchmarking against a Saccharomyces boulardii strain with probiotic effects documented in clinical trials, we evaluated the ability of K. marxianus to modulate human dendritic cell (DC) function in vitro. Further, we assessed yeast induced DC modulation of naive T cells toward effector responses dominated by secretion of IFNγ and IL-17 versus induction of a Treg response characterized by robust IL-10 secretion. In addition, we blocked relevant DC surface receptors and investigated the stimulating properties of β-glucan containing yeast cell wall extracts. K. marxianus and S. boulardii induced distinct levels of DC cytokine secretion, primarily driven by Dectin-1 recognition of β-glucan components in their cell walls. Upon co-incubation of yeast exposed DCs and naive T cells, S. boulardii induced a potent IFNγ response indicating TH1 mobilization. In contrast, K. marxianus induced a response dominated by Foxp3+ Treg cells, a characteristic that may benefit human health in conditions characterized by excessive inflammation and positions K. marxianus as a strong candidate for further development as a novel yeast probiotic.

Portable exhauster POR-007/Skid E and POR-008/Skid F storage plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, O.D.

1998-07-25

This document provides storage requirements for 1,000 CFM portable exhausters POR-O07/Skid E and POR-008/Skid F. These requirements are presented in three parts: preparation for storage, storage maintenance and testing, and retrieval from storage. The exhauster component identification numbers listed in this document contain the prefix POR-007 or POR-008 depending on which exhauster is being used.

Heterologous expression of an α-amylase inhibitor from common bean (Phaseolus vulgaris) in Kluyveromyces lactis and Saccharomyces cerevisiae.

PubMed

Brain-Isasi, Stephanie; Álvarez-Lueje, Alejandro; Higgins, Thomas Joseph V

2017-06-15

Phaseolamin or α-amylase inhibitor 1 (αAI) is a glycoprotein from common beans (Phaseolus vulgaris L.) that inhibits some insect and mammalian α-amylases. Several clinical studies support the beneficial use of bean αAI for control of diabetes and obesity. Commercial extracts of P. vulgaris are available but their efficacy is still under question, mainly because some of these extracts contain antinutritional impurities naturally present in bean seeds and also exhibit a lower specific activity αAI. The production of recombinant αAI allows to overcome these disadvantages and provides a platform for the large-scale production of pure and functional αAI protein for biotechnological and pharmaceutical applications. A synthetic gene encoding αAI from the common bean (Phaseolus vulgaris cv. Pinto) was codon-optimised for expression in yeasts (αAI-OPT) and cloned into the protein expression vectors pKLAC2 and pYES2. The yeasts Kluyveromyces lactis GG799 (and protease deficient derivatives such as YCT390) and Saccharomyces cerevisiae YPH499 were transformed with the optimised genes and transformants were screened for expression by antibody dot blot. Recombinant colonies of K. lactis YCT390 that expressed and secreted functional αAI into the culture supernatants were selected for further analyses. Recombinant αAI from K. lactis YCT390 was purified using anion-exchange and affinity resins leading to the recovery of a functional inhibitor. The identity of the purified αAI was confirmed by mass spectrometry. Recombinant clones of S. cerevisiae YPH499 expressed functional αAI intracellularly, but did not secrete the protein. This is the first report describing the heterologous expression of the α-amylase inhibitor 1 (αAI) from P. vulgaris in yeasts. We demonstrated that recombinant strains of K. lactis and S. cerevisiae expressed and processed the αAI precursor into mature and active protein and also showed that K. lactis secretes functional αAI.

Growth kinetics and physiological behavior of co-cultures of Saccharomyces cerevisiae and Kluyveromyces lactis, fermenting carob sugars extracted with whey.

PubMed

Rodrigues, B; Lima-Costa, M E; Constantino, A; Raposo, S; Felizardo, C; Gonçalves, D; Fernandes, T; Dionísio, L; Peinado, J M

2016-10-01

Alcoholic fermentation of carob waste sugars (sucrose, glucose and fructose) extracted with cheese whey, by co-cultures of Saccharomyces cerevisiae and Kluyveromyces lactis has been analyzed. Growth and fermentation of S. cerevisiae in the carob-whey medium showed an inhibition of about 30% in comparison with water-extracted carob. The inhibition of K. lactis on carob-whey was greater (70%) when compared with the whey medium alone, due to osmolarity problems. Oxygen availability was a very important factor for K. lactis, influencing its fermentation performance. When K. lactis was grown alone on carob-whey medium, lactose was always consumed first, and glucose and fructose were consumed afterwards, only at high aeration conditions. In co-culture with S. cerevisiae, K. lactis was completely inhibited and, at low aeration, died after 3 days; at high aeration this culture could survive but growth and lactose fermentation were only recovered after S. cerevisiae became stationary. To overcome the osmolarity and K. lactis' oxygen problems, the medium had to be diluted and a sequential fermentative process was designed in a STR-3l reactor. K. lactis was inoculated first and, with low aeration (0.13vvm), consumed all the lactose in 48h. Then S. cerevisiae was inoculated, consuming the total of the carob sugars, and producing ethanol in a fed-batch regime. The established co-culture with K. lactis increased S. cerevisiae ethanol tolerance. This fermentation process produced ethanol with good efficiency (80g/l final concentration and a conversion factor of 0.4g ethanol/g sugar), eliminating all the sugars of the mixed waste. These efficient fermentative results pointed to a new joint treatment of agro-industrial wastes which may be implemented successfully, with economic and environmental sustainability for a bioethanol industrial proposal. Copyright © 2016 Elsevier Inc. All rights reserved.

Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System.

PubMed

Gorasia, Dhana G; Veith, Paul D; Hanssen, Eric G; Glew, Michelle D; Sato, Keiko; Yukitake, Hideharu; Nakayama, Koji; Reynolds, Eric C

2016-08-01

The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32-36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component.

Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System

PubMed Central

Gorasia, Dhana G.; Veith, Paul D.; Hanssen, Eric G.; Glew, Michelle D.; Sato, Keiko; Yukitake, Hideharu; Nakayama, Koji; Reynolds, Eric C.

2016-01-01

The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32–36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component. PMID:27509186

The PorX Response Regulator of the Porphyromonas gingivalis PorXY Two-Component System Does Not Directly Regulate the Type IX Secretion Genes but Binds the PorL Subunit

PubMed Central

Vincent, Maxence S.; Durand, Eric; Cascales, Eric

2016-01-01

The Type IX secretion system (T9SS) is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion or cell surface exposition of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY, and PorX encode typical two-component system (TCS) sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN, and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we demonstrate that PorX does not bind T9SS gene promoters and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS. PMID:27630829

Novel technology development through thermal drying of encapsulated Kluyveromyces marxianus in micro- and nano-tubular cellulose in lactose fermentation and its evaluation for food production.

PubMed

Papapostolou, Harris; Servetas, Yiannis; Bosnea, Loulouda A; Kanellaki, Maria; Koutinas, Athanasios A

2012-12-01

A novel technology development based on the production of a low-cost starter culture for ripening of cheeses and baking is reported in the present study. The starter culture comprises thermally dried cells of Kluyveromyces marxianus encapsulated in micro- and nano-tubular cellulose. For production of a low-cost and effective biocatalyst, whey was used as raw material for biomass production and thermal drying methods (convective, conventional, and vacuum) were applied and evaluated at drying temperatures ranging from 35 to 60 °C. The effect of drying temperature of biocatalysts on fermentability of lactose and whey was evaluated. Storage stability and suitability of biocatalysts as a commercial starter cultures was also assessed and evaluated. All thermally dried biocatalysts were found to be active in lactose and whey fermentation. In all cases, there was sugar conversion ranging from 92 to 100 %, ethanol concentration of up to 1.47 % (v/v), and lactic acid concentrations ranged from 4.1 to 5.5 g/l. However, convective drying of the encapsulated cells of K. marxianus in micro- and nano-tubular cellulose was faster and a more effective drying method while drying at 42 °C appear to be the best drying temperature in terms of cell activity, ethanol, and lactic acid formation. Storage of the biocatalysts for 3 months at 4 °C proved maintenance of its activity even though fermentation times increased by 50-100 % compared with the fresh dried ones.

Purification and characterization of a novel tannase produced by Kluyveromyces marxianus using olive pomace as solid support, and its promising role in gallic acid production.

PubMed

Mahmoud, Abeer E; Fathy, Shadia A; Rashad, Mona M; Ezz, Magda K; Mohammed, Amira T

2018-02-01

Tannase is considered one of the most important industrial enzymes that find great applications in various sectors. Production of tannases through solid state fermentation (SSF) using agro-industrial wastes is an eco-friendly and cheap technology. Tannase was produced by the yeast Kluyveromyces marxianus using olive pomace as a solid support under SSF. It was purified using ammonium sulfate fractional precipitation followed by Sephadex G-200 gel filtration resulting in 64.6% enzyme yield with 1026.12U/mg specific activity and 24.21 purification fold. Pure tannase had molecular weight of 65 KDa and 66.62 KDa by SDS-PAGE and gel filtration, respectively. It showed a maximal activity at 35°C having two different pH optima, one of which is acidic (4.5) and the other one is alkaline (8.5). The enzyme was stable in the acidic range of pH (4.0-5.5) for 30min, and thermostable within the temperature range 30-70°C. Using tannic acid, the enzyme had a Km value of 0.77mM and Vmax of 263.20μmolemin -1 ml -1 . The effect of different metal ions on enzymatic activity was evaluated. HPLC analysis data indicated that the purified enzyme could carry out 24.65% tannic acid conversion with 5.25 folds increase in gallic acid concentration within 30min only. Copyright © 2017 Elsevier B.V. All rights reserved.

Automated UV-C mutagenesis of Kluyveromyces marxianus NRRL Y-1109 and selection for microaerophilic growth and ethanol production at elevated temperature on biomass sugars.

PubMed

Hughes, Stephen R; Bang, Sookie S; Cox, Elby J; Schoepke, Andrew; Ochwat, Kate; Pinkelman, Rebecca; Nelson, Danielle; Qureshi, Nasib; Gibbons, William R; Kurtzman, Cletus P; Bischoff, Kenneth M; Liu, Siqing; Cote, Gregory L; Rich, Joseph O; Jones, Marjorie A; Cedeño, David; Doran-Peterson, Joy; Riaño-Herrera, Nestor M; Rodríguez-Valencia, Nelson; López-Núñez, Juan C

2013-08-01

The yeast Kluyveromyces marxianus is a potential microbial catalyst for fuel ethanol production from a wide range of biomass substrates. To improve its growth and ethanol yield at elevated temperature under microaerophilic conditions, K. marxianus NRRL Y-1109 was irradiated with UV-C using automated protocols on a robotic platform for picking and spreading irradiated cultures and for processing the resulting plates. The plates were incubated under anaerobic conditions on xylose or glucose for 5 mo at 46 °C. Two K. marxianus mutant strains (designated 7-1 and 8-1) survived and were isolated from the glucose plates. Both mutant strains, but not wild type, grew aerobically on glucose at 47 °C. All strains grew anaerobically at 46 °C on glucose, galactose, galacturonic acid, and pectin; however, only 7-1 grew anaerobically on xylose at 46 °C. Saccharomyces cerevisiae NRRL Y-2403 did not grow at 46 °C on any of these substrates. With glucose as a carbon source, ethanol yield after 3 d at 46 °C was higher for 8-1 than for wild type (0.51 and 0.43 g ethanol/g glucose, respectively). With galacturonic acid as a carbon source, the ethanol yield after 7 d at 46 °C was higher for 7-1 than for wild type (0.48 and 0.34 g ethanol/g galacturonic acid, respectively). These mutant strains have potential application in fuel ethanol production at elevated temperature from sugar constituents of starch, sucrose, pectin, and cellulosic biomass.

Use of synthetic genes for cloning, production and functional expression of the bacteriocins enterocin A and bacteriocin E 50-52 by Pichia pastoris and Kluyveromyces lactis.

PubMed

Jiménez, Juan J; Borrero, Juan; Gútiez, Loreto; Arbulu, Sara; Herranz, Carmen; Cintas, Luis M; Hernández, Pablo E

2014-06-01

The use of synthetic genes may constitute a successful approach for the heterologous production and functional expression of bacterial antimicrobial peptides (bacteriocins) by recombinant yeasts. In this work, synthetic genes with adapted codon usage designed from the mature amino acid sequence of the bacteriocin enterocin A (EntA), produced by Enterococcus faecium T136, and the mature bacteriocin E 50-52 (BacE50-52), produced by E. faecium NRRL B-32746, were synthesized. The synthetic entA and bacE50-52 were cloned into the protein expression vectors pPICZαA and pKLAC2 for transformation of derived vectors into Pichia pastoris X-33 and Kluyveromyces lactis GG799, respectively. The recombinant vectors were linearized and transformed into competent cells selecting for P. pastoris X-33EAS (entA), P. pastoris X-33BE50-52S (bacE50-52), K. lactis GG799EAS (entA), and K. lactis GG799BE50-52S (bacE50-52). P. pastoris X-33EAS and K. lactis GG799EAS, but not P. pastoris X-33BE50-52S and K. lactis GG799BE50-52S, showed antimicrobial activity in their supernatants. However, purification of the supernatants of the producer yeasts permitted recovery of the bacteriocins EntA and BacE50-52. Both purified bacteriocins were active against Gram-positive bacteria such as Listeria monocytogenes but not against Gram-negative bacteria, including Campylobacter jejuni.

Novel transporters from Kluyveromyces marxianus and Pichia guilliermondii expressed in Saccharomyces cerevisiae enable growth on L-arabinose and D-xylose.

PubMed

Knoshaug, Eric P; Vidgren, Virve; Magalhães, Frederico; Jarvis, Eric E; Franden, Mary Ann; Zhang, Min; Singh, Arjun

2015-10-01

Genes encoding L-arabinose transporters in Kluyveromyces marxianus and Pichia guilliermondii were identified by functional complementation of Saccharomyces cerevisiae whose growth on L-arabinose was dependent on a functioning L-arabinose transporter, or by screening a differential display library, respectively. These transporters also transport D-xylose and were designated KmAXT1 (arabinose-xylose transporter) and PgAXT1, respectively. Transport assays using L-arabinose showed that KmAxt1p has K(m) 263 mM and V(max) 57 nM/mg/min, and PgAxt1p has K(m) 0.13 mM and V(max) 18 nM/mg/min. Glucose, galactose and xylose significantly inhibit L-arabinose transport by both transporters. Transport assays using D-xylose showed that KmAxt1p has K(m) 27 mM and V(max) 3.8 nM/mg/min, and PgAxt1p has K(m) 65 mM and V(max) 8.7 nM/mg/min. Neither transporter is capable of recovering growth on glucose or galactose in a S. cerevisiae strain deleted for hexose and galactose transporters. Transport kinetics of S. cerevisiae Gal2p showed K(m) 371 mM and V(max) 341 nM/mg/min for L-arabinose, and K(m) 25 mM and V(max) 76 nM/mg/min for galactose. Due to the ability of Gal2p and these two newly characterized transporters to transport both L-arabinose and D-xylose, one scenario for the complete usage of biomass-derived pentose sugars would require only the low-affinity, high-throughput transporter Gal2p and one additional high-affinity general pentose transporter, rather than dedicated D-xylose or L-arabinose transporters. Additionally, alignment of these transporters with other characterized pentose transporters provides potential targets for substrate recognition engineering. Copyright © 2015 John Wiley & Sons, Ltd.

Functional and Structural Characterization of Purine Nucleoside Phosphorylase from Kluyveromyces lactis and Its Potential Applications in Reducing Purine Content in Food

PubMed Central

Mahor, Durga; Priyanka, Anu; Prasad, Gandham S; Thakur, Krishan Gopal

2016-01-01

Consumption of foods and beverages with high purine content increases the risk of hyperuricemia, which causes gout and can lead to cardiovascular, renal, and other metabolic disorders. As patients often find dietary restrictions challenging, enzymatically lowering purine content in popular foods and beverages offers a safe and attractive strategy to control hyperuricemia. Here, we report structurally and functionally characterized purine nucleoside phosphorylase (PNP) from Kluyveromyces lactis (KlacPNP), a key enzyme involved in the purine degradation pathway. We report a 1.97 Å resolution crystal structure of homotrimeric KlacPNP with an intrinsically bound hypoxanthine in the active site. KlacPNP belongs to the nucleoside phosphorylase-I (NP-I) family, and it specifically utilizes 6-oxopurine substrates in the following order: inosine > guanosine > xanthosine, but is inactive towards adenosine. To engineer enzymes with broad substrate specificity, we created two point variants, KlacPNPN256D and KlacPNPN256E, by replacing the catalytically active Asn256 with Asp and Glu, respectively, based on structural and comparative sequence analysis. KlacPNPN256D not only displayed broad substrate specificity by utilizing both 6-oxopurines and 6-aminopurines in the order adenosine > inosine > xanthosine > guanosine, but also displayed reversal of substrate specificity. In contrast, KlacPNPN256E was highly specific to inosine and could not utilize other tested substrates. Beer consumption is associated with increased risk of developing gout, owing to its high purine content. Here, we demonstrate that KlacPNP and KlacPNPN256D could be used to catalyze a key reaction involved in lowering beer purine content. Biochemical properties of these enzymes such as activity across a wide pH range, optimum activity at about 25°C, and stability for months at about 8°C, make them suitable candidates for food and beverage industries. Since KlacPNPN256D has broad substrate specificity, a

Oxygen-Dependent Transcriptional Regulator Hap1p Limits Glucose Uptake by Repressing the Expression of the Major Glucose Transporter Gene RAG1 in Kluyveromyces lactis▿

PubMed Central

Bao, Wei-Guo; Guiard, Bernard; Fang, Zi-An; Donnini, Claudia; Gervais, Michel; Passos, Flavia M. Lopes; Ferrero, Iliana; Fukuhara, Hiroshi; Bolotin-Fukuhara, Monique

2008-01-01

The HAP1 (CYP1) gene product of Saccharomyces cerevisiae is known to regulate the transcription of many genes in response to oxygen availability. This response varies according to yeast species, probably reflecting the specific nature of their oxidative metabolism. It is suspected that a difference in the interaction of Hap1p with its target genes may explain some of the species-related variation in oxygen responses. As opposed to the fermentative S. cerevisiae, Kluyveromyces lactis is an aerobic yeast species which shows different oxygen responses. We examined the role of the HAP1-equivalent gene (KlHAP1) in K. lactis. KlHap1p showed a number of sequence features and some gene targets (such as KlCYC1) in common with its S. cerevisiae counterpart, and KlHAP1 was capable of complementing the hap1 mutation. However, the KlHAP1 disruptant showed temperature-sensitive growth on glucose, especially at low glucose concentrations. At normal temperature, 28°C, the mutant grew well, the colony size being even greater than that of the wild type. The most striking observation was that KlHap1p repressed the expression of the major glucose transporter gene RAG1 and reduced the glucose uptake rate. This suggested an involvement of KlHap1p in the regulation of glycolytic flux through the glucose transport system. The ΔKlhap1 mutant showed an increased ability to produce ethanol during aerobic growth, indicating a possible transformation of its physiological property to Crabtree positivity or partial Crabtree positivity. Dual roles of KlHap1p in activating respiration and repressing fermentation may be seen as a basis of the Crabtree-negative physiology of K. lactis. PMID:18806211

Hydrogen-driven asymmetric reduction of hydroxyacetone to (R)-1,2-propanediol by Ralstonia eutropha transformant expressing alcohol dehydrogenase from Kluyveromyces lactis.

PubMed

Oda, Takahiro; Oda, Koji; Yamamoto, Hiroaki; Matsuyama, Akinobu; Ishii, Masaharu; Igarashi, Yasuo; Nishihara, Hirofumi

2013-01-10

Conversion of industrial processes to more nature-friendly modes is a crucial subject for achieving sustainable development. Utilization of hydrogen-oxidation reactions by hydrogenase as a driving force of bioprocess reaction can be an environmentally ideal method because the reaction creates no pollutants. We expressed NAD-dependent alcohol dehydrogenase from Kluyveromyces lactis in a hydrogen-oxidizing bacterium: Ralstonia eutropha. This is the first report of hydrogen-driven in vivo coupling reaction of the alcohol dehydrogenase and indigenous soluble NAD-reducing hydrogenase. Asymmetric reduction of hydroxyacetone to (R)-1,2-propanediol, which is a commercial building block for antibacterial agents, was performed using the transformant as the microbial cell catalyst. The two enzymes coupled in vitro in vials without a marked decrease of reactivity during the 20 hr reaction because of the hydrogenase reaction, which generates no by-product that affects enzymes. Alcohol dehydrogenase was expressed functionally in R. eutropha in an activity level equivalent to that of indigenous NAD-reducing hydrogenase under the hydrogenase promoter. The hydrogen-driven in vivo coupling reaction proceeded only by the transformant cell without exogenous addition of a cofactor. The decrease of reaction velocity at higher concentration of hydroxyacetone was markedly reduced by application of an in vivo coupling system. Production of (R)-1,2-propanediol (99.8% e.e.) reached 67.7 g/l in 76 hr with almost a constant rate using a jar fermenter. The reaction velocity under 10% PH2 was almost equivalent to that under 100% hydrogen, indicating the availability of crude hydrogen gas from various sources. The in vivo coupling system enabled cell-recycling as catalysts. Asymmetric reduction of hydroxyacetone by a coupling reaction of the two enzymes continued in both in vitro and in vivo systems in the presence of hydrogen. The in vivo reaction system using R. eutropha transformant expressing

Use of the KlADH3 promoter for the quantitative production of the murine PDE5A isoforms in the yeast Kluyveromyces lactis.

PubMed

Cardarelli, Silvia; Giorgi, Mauro; Naro, Fabio; Malatesta, Francesco; Biagioni, Stefano; Saliola, Michele

2017-09-22

Phosphodiesterases (PDE) are a superfamily of enzymes that hydrolyse cyclic nucleotides (cAMP/cGMP), signal molecules in transduction pathways regulating crucial aspects of cell life. PDEs regulate the intensity and duration of the cyclic nucleotides signal modulating the downstream biological effect. Due to this critical role associated with the extensive distribution and multiplicity of isozymes, the 11 mammalian families (PDE1 to PDE11) constitute key therapeutic targets. PDE5, one of these cGMP-specific hydrolysing families, is the molecular target of several well known drugs used to treat erectile dysfunction and pulmonary hypertension. Kluyveromyces lactis, one of the few yeasts capable of utilizing lactose, is an attractive host alternative to Saccharomyces cerevisiae for heterologous protein production. Here we established K. lactis as a powerful host for the quantitative production of the murine PDE5 isoforms. Using the promoter of the highly expressed KlADH3 gene, multicopy plasmids were engineered to produce the native and recombinant Mus musculus PDE5 in K. lactis. Yeast cells produced large amounts of the purified A1, A2 and A3 isoforms displaying K m , V max and Sildenafil inhibition values similar to those of the native murine enzymes. PDE5 whose yield was nearly 1 mg/g wet weight biomass for all three isozymes (30 mg/L culture), is well tolerated by K. lactis cells without major growth deficiencies and interferences with the endogenous cAMP/cGMP signal transduction pathways. To our knowledge, this is the first time that the entire PDE5 isozymes family containing both regulatory and catalytic domains has been produced at high levels in a heterologous eukaryotic organism. K. lactis has been shown to be a very promising host platform for large scale production of mammalian PDEs for biochemical and structural studies and for the development of new specific PDE inhibitors for therapeutic applications in many pathologies.

Ethanol yield and volatile compound content in fermentation of agave must by Kluyveromyces marxianus UMPe-1 comparing with Saccharomyces cerevisiae baker's yeast used in tequila production.

PubMed

López-Alvarez, Arnoldo; Díaz-Pérez, Alma Laura; Sosa-Aguirre, Carlos; Macías-Rodríguez, Lourdes; Campos-García, Jesús

2012-05-01

In tequila production, fermentation is an important step. Fermentation determines the ethanol productivity and organoleptic properties of the beverage. In this study, a yeast isolated from native residual agave must was identified as Kluyveromyces marxianus UMPe-1 by 26S rRNA sequencing. This yeast was compared with the baker's yeast Saccharomyces cerevisiae Pan1. Our findings demonstrate that the UMPe-1 yeast was able to support the sugar content of agave must and glucose up to 22% (w/v) and tolerated 10% (v/v) ethanol concentration in the medium with 50% cells survival. Pilot and industrial fermentation of agave must tests showed that the K. marxianus UMPe-1 yeast produced ethanol with yields of 94% and 96% with respect to fermentable sugar content (glucose and fructose, constituting 98%). The S. cerevisiae Pan1 baker's yeast, however, which is commonly used in some tequila factories, showed 76% and 70% yield. At the industrial level, UMPe-1 yeast shows a maximum velocity of fermentable sugar consumption of 2.27g·L(-1)·h(-1) and ethanol production of 1.38g·L(-1)·h(-1), providing 58.78g ethanol·L(-1) at 72h fermentation, which corresponds to 96% yield. In addition, the major and minor volatile compounds in the tequila beverage obtained from UMPe-1 yeast were increased. Importantly, 29 volatile compounds were identified, while the beverage obtained from Pan1-yeast contained fewer compounds and in lower concentrations. The results suggest that the K. marxianus UMPe-1 is a suitable yeast for agave must fermentation, showing high ethanol productivity and increased volatile compound content comparing with a S. cerevisiae baker's yeast used in tequila production. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Identification of Porphyromonas gingivalis proteins secreted by the Por secretion system.

PubMed

Sato, Keiko; Yukitake, Hideharu; Narita, Yuka; Shoji, Mikio; Naito, Mariko; Nakayama, Koji

2013-01-01

The Gram-negative bacterium Porphyromonas gingivalis possesses a number of potential virulence factors for periodontopathogenicity. In particular, cysteine proteinases named gingipains are of interest given their abilities to degrade host proteins and process other virulence factors such as fimbriae. Gingipains are translocated on the cell surface or into the extracellular milieu by the Por secretion system (PorSS), which consists of a number of membrane or periplasmic proteins including PorK, PorL, PorM, PorN, PorO, PorP, PorQ, PorT, PorU, PorV (PG27, LptO), PorW and Sov. To identify proteins other than gingipains secreted by the PorSS, we compared the proteomes of P. gingivalis strains kgp rgpA rgpB (PorSS-proficient strain) and kgp rgpA rgpB porK (PorSS-deficient strain) using two-dimensional gel electrophoresis and peptide-mass fingerprinting. Sixteen spots representing 10 different proteins were present in the particle-free culture supernatant of the PorSS-proficient strain but were absent or faint in that of the PorSS-deficient strain. These identified proteins possessed the C-terminal domains (CTDs), which had been suggested to form the CTD protein family. These results indicate that the PorSS is used for secretion of a number of proteins other than gingipains and that the CTDs of the proteins are associated with the PorSS-dependent secretion. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Suppression of Cytochrome P450 Reductase (POR) Expression in Hepatoma Cells Replicates the Hepatic Lipidosis Observed in Hepatic POR-Null Mice

PubMed Central

Banerjee, Subhashis; Stolarczyk, Elzbieta I.; Zou, Ling

2011-01-01

Cytochrome P450 reductase (POR) is a microsomal electron transport protein essential to cytochrome P450-mediated drug metabolism and sterol and bile acid synthesis. The conditional deletion of hepatic POR gene expression in mice results in a marked decrease in plasma cholesterol levels counterbalanced by the accumulation of triglycerides in lipid droplets in hepatocytes. To evaluate the role of cholesterol and bile acid synthesis in this hepatic lipidosis, as well as the possible role of lipid transport from peripheral tissues, we developed a stable, small interfering RNA (siRNA)-mediated cell culture model for the suppression of POR. POR mRNA and protein expression were decreased by greater than 50% in McArdle-RH7777 rat hepatoma cells 10 days after transfection with a POR-siRNA expression plasmid, and POR expression was nearly completely extinguished by day 20. Immunofluorescent analysis revealed a marked accumulation of lipid droplets in cells by day 15, accompanied by a nearly 2-fold increase in cellular triglyceride content, replicating the lipidosis seen in hepatic POR-null mouse liver. In contrast, suppression of CYP51A1 (lanosterol demethylase) did not result in lipid accumulation, indicating that loss of cholesterol synthesis is not the basis for this lipidosis. Indeed, addition of cholesterol to the medium appeared to augment the lipidosis in POR-suppressed cells, whereas removal of lipids from the medium reversed the lipidosis. Oxysterols did not accumulate in POR-suppressed cells, discounting a role for liver X receptor in stimulating triglyceride synthesis, but addition of chenodeoxycholate significantly repressed lipid accumulation, suggesting that the absence of bile acids and loss of farnesoid X receptor stimulation lead to excessive triglyceride synthesis. PMID:21368239

Suppression of cytochrome P450 reductase (POR) expression in hepatoma cells replicates the hepatic lipidosis observed in hepatic POR-null mice.

PubMed

Porter, Todd D; Banerjee, Subhashis; Stolarczyk, Elzbieta I; Zou, Ling

2011-06-01

Cytochrome P450 reductase (POR) is a microsomal electron transport protein essential to cytochrome P450-mediated drug metabolism and sterol and bile acid synthesis. The conditional deletion of hepatic POR gene expression in mice results in a marked decrease in plasma cholesterol levels counterbalanced by the accumulation of triglycerides in lipid droplets in hepatocytes. To evaluate the role of cholesterol and bile acid synthesis in this hepatic lipidosis, as well as the possible role of lipid transport from peripheral tissues, we developed a stable, small interfering RNA (siRNA)-mediated cell culture model for the suppression of POR. POR mRNA and protein expression were decreased by greater than 50% in McArdle-RH7777 rat hepatoma cells 10 days after transfection with a POR-siRNA expression plasmid, and POR expression was nearly completely extinguished by day 20. Immunofluorescent analysis revealed a marked accumulation of lipid droplets in cells by day 15, accompanied by a nearly 2-fold increase in cellular triglyceride content, replicating the lipidosis seen in hepatic POR-null mouse liver. In contrast, suppression of CYP51A1 (lanosterol demethylase) did not result in lipid accumulation, indicating that loss of cholesterol synthesis is not the basis for this lipidosis. Indeed, addition of cholesterol to the medium appeared to augment the lipidosis in POR-suppressed cells, whereas removal of lipids from the medium reversed the lipidosis. Oxysterols did not accumulate in POR-suppressed cells, discounting a role for liver X receptor in stimulating triglyceride synthesis, but addition of chenodeoxycholate significantly repressed lipid accumulation, suggesting that the absence of bile acids and loss of farnesoid X receptor stimulation lead to excessive triglyceride synthesis.

Biological interactions to select biocontrol agents against toxigenic strains of Aspergillus flavus and Fusarium verticillioides from maize.

PubMed

Etcheverry, Miriam G; Scandolara, Andrea; Nesci, Andrea; Vilas Boas Ribeiro, Marta Sofia; Pereira, Paola; Battilani, Paola

2009-05-01

Biological control represent an alternative to the use of pesticides in crop protection. A key to progress in biological control to protect maize against Fusarium verticillioides and Aspergillus flavus maize pathogens are, to select in vitro, the best agent to be applied in the field. The aim of this study was to examine the antagonistic activity of bacterial and yeast isolates against F.verticillioides and A. flavus toxigenic strains. The first study showed the impact of Bacillus amyloliquefaciens BA-S13, Microbacterium oleovorans DMS 16091, Enterobacter hormomaechei EM-562T, and Kluyveromyces spp. L14 and L16 isolates on mycelial growth of two strains of A. flavus MPVPA 2092, 2094 and three strains of F. verticillioides MPVPA 285, 289, and 294 on 3% maize meal extract agar at different water activities (0.99, 0.97, 0.95, and 0.93). From this first assay antagonistics isolates M. oleovorans, B. amyloliquefaciens and Kluyveromyces sp. (L16) produced an increase of lag phase of growth and decreased a growth rate of all fungal strains. These isolates were selected for futher studies. In vitro non-rhizospheric maize soil (centrally and sprayed inoculated) and in vitro maize (ears apex and base inoculated) were treated with antagonistics and pathogenic strains alone in co-inoculated cultures. Bacillus amyloliquefaciens significantly reduced F. verticillioides and A. flavus count in maize soil inoculated centrally. Kluyveromyces sp. L16 reduced F. verticillioides and A. flavus count in maize soil inoculated by spray. Kluyveromyces sp. L16 was the most effective treatment limiting percent infections by F. verticillioides on the maize ears.

System design description for portable 1,000 CFM exhauster Skids POR-007/Skid E and POR-008/Skid F

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, O.D.

1998-07-25

The primary purpose of the two 1,000 CFM Exhauster Skids, POR-007-SKID E and POR-008-SKID F, is to provide backup to the waste tank primary ventilation systems for tanks 241-C-106 and 241-AY-102, and the AY-102 annulus in the event of a failure during the sluicing of tank 241-C-106 and subsequent transfer of sluiced waste to 241-AY-102. This redundancy is required since both of the tank ventilation systems have been declared as Safety Class systems.

Yeast Interspecies Comparative Proteomics Reveals Divergence in Expression Profiles and Provides Insights into Proteome Resource Allocation and Evolutionary Roles of Gene Duplication*

PubMed Central

Kito, Keiji; Ito, Haruka; Nohara, Takehiro; Ohnishi, Mihoko; Ishibashi, Yuko; Takeda, Daisuke

2016-01-01

Omics analysis is a versatile approach for understanding the conservation and diversity of molecular systems across multiple taxa. In this study, we compared the proteome expression profiles of four yeast species (Saccharomyces cerevisiae, Saccharomyces mikatae, Kluyveromyces waltii, and Kluyveromyces lactis) grown on glucose- or glycerol-containing media. Conserved expression changes across all species were observed only for a small proportion of all proteins differentially expressed between the two growth conditions. Two Kluyveromyces species, both of which exhibited a high growth rate on glycerol, a nonfermentative carbon source, showed distinct species-specific expression profiles. In K. waltii grown on glycerol, proteins involved in the glyoxylate cycle and gluconeogenesis were expressed in high abundance. In K. lactis grown on glycerol, the expression of glycolytic and ethanol metabolic enzymes was unexpectedly low, whereas proteins involved in cytoplasmic translation, including ribosomal proteins and elongation factors, were highly expressed. These marked differences in the types of predominantly expressed proteins suggest that K. lactis optimizes the balance of proteome resource allocation between metabolism and protein synthesis giving priority to cellular growth. In S. cerevisiae, about 450 duplicate gene pairs were retained after whole-genome duplication. Intriguingly, we found that in the case of duplicates with conserved sequences, the total abundance of proteins encoded by a duplicate pair in S. cerevisiae was similar to that of protein encoded by nonduplicated ortholog in Kluyveromyces yeast. Given the frequency of haploinsufficiency, this observation suggests that conserved duplicate genes, even though minor cases of retained duplicates, do not exhibit a dosage effect in yeast, except for ribosomal proteins. Thus, comparative proteomic analyses across multiple species may reveal not only species-specific characteristics of metabolic processes under

Native yeasts for alternative utilization of overripe mango pulp for ethanol production.

PubMed

Buenrostro-Figueroa, Juan; Tafolla-Arellano, Julio C; Flores-Gallegos, Adriana C; Rodríguez-Herrera, Raúl; De la Garza-Toledo, Heliodoro; Aguilar, Cristóbal N

2017-11-18

Mango fruits (Mangifera indica L.) are highly perishable, causing postharvest losses and producing agroindustrial waste. In the present work, native yeasts were used to evaluate ethanol production in overripe mango pulp. The two isolated strains showed similar sequences in the 18S rDNA region corresponding to Kluyveromyces marxianus, being different to the data reported in the NCBI database. Values of up to 5% ethanol (w/v) were obtained at the end of fermentation, showing a productivity of 4g/l/day, a yield of up to 49% of ethanol and a process efficiency of 80%. These results represent a viable option for using the surplus production and all the fruits that have suffered mechanical injury that are not marketable and are considered as agroindustrial waste, thus achieving greater income and less postharvest losses. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Yeast Interspecies Comparative Proteomics Reveals Divergence in Expression Profiles and Provides Insights into Proteome Resource Allocation and Evolutionary Roles of Gene Duplication.

PubMed

Kito, Keiji; Ito, Haruka; Nohara, Takehiro; Ohnishi, Mihoko; Ishibashi, Yuko; Takeda, Daisuke

2016-01-01

Omics analysis is a versatile approach for understanding the conservation and diversity of molecular systems across multiple taxa. In this study, we compared the proteome expression profiles of four yeast species (Saccharomyces cerevisiae, Saccharomyces mikatae, Kluyveromyces waltii, and Kluyveromyces lactis) grown on glucose- or glycerol-containing media. Conserved expression changes across all species were observed only for a small proportion of all proteins differentially expressed between the two growth conditions. Two Kluyveromyces species, both of which exhibited a high growth rate on glycerol, a nonfermentative carbon source, showed distinct species-specific expression profiles. In K. waltii grown on glycerol, proteins involved in the glyoxylate cycle and gluconeogenesis were expressed in high abundance. In K. lactis grown on glycerol, the expression of glycolytic and ethanol metabolic enzymes was unexpectedly low, whereas proteins involved in cytoplasmic translation, including ribosomal proteins and elongation factors, were highly expressed. These marked differences in the types of predominantly expressed proteins suggest that K. lactis optimizes the balance of proteome resource allocation between metabolism and protein synthesis giving priority to cellular growth. In S. cerevisiae, about 450 duplicate gene pairs were retained after whole-genome duplication. Intriguingly, we found that in the case of duplicates with conserved sequences, the total abundance of proteins encoded by a duplicate pair in S. cerevisiae was similar to that of protein encoded by nonduplicated ortholog in Kluyveromyces yeast. Given the frequency of haploinsufficiency, this observation suggests that conserved duplicate genes, even though minor cases of retained duplicates, do not exhibit a dosage effect in yeast, except for ribosomal proteins. Thus, comparative proteomic analyses across multiple species may reveal not only species-specific characteristics of metabolic processes under

Dregs of our forgotten ancestors: fermentative microorganisms in the prehistory of Europe, the steppes and Indo-Iranian Asia, and their contemporary use in traditional and probiotic beverages

USDA-ARS?s Scientific Manuscript database

Fermentative microorganisms in the yeast genera Debaryomyces, Hyphopichia, Kluyveromyces, Lachancea, Saccharomyces, and Wickerhamomyces (and in the bacterial genus Lactobacillus) have been isolated from a variety of fermented beverages. These same microorganisms were very likely unknowingly utilized...

Outer membrane vesicles from Neisseria gonorrhoeae target PorB to mitochondria and induce apoptosis

PubMed Central

Elgass, Kirstin D.; Gabriel, Kipros; Dougan, Gordon; Lithgow, Trevor; Heinz, Eva

2018-01-01

Neisseria gonorrhoeae causes the sexually transmitted disease gonorrhoea by evading innate immunity. Colonizing the mucosa of the reproductive tract depends on the bacterial outer membrane porin, PorB, which is essential for ion and nutrient uptake. PorB is also targeted to host mitochondria and regulates apoptosis pathways to promote infections. How PorB traffics from the outer membrane of N. gonorrhoeae to mitochondria and whether it modulates innate immune cells, such as macrophages, remains unclear. Here, we show that N. gonorrhoeae secretes PorB via outer membrane vesicles (OMVs). Purified OMVs contained primarily outer membrane proteins including oligomeric PorB. The porin was targeted to mitochondria of macrophages after exposure to purified OMVs and wild type N. gonorrhoeae. This was associated with loss of mitochondrial membrane potential, release of cytochrome c, activation of apoptotic caspases and cell death in a time-dependent manner. Consistent with this, OMV-induced macrophage death was prevented with the pan-caspase inhibitor, Q-VD-PH. This shows that N. gonorrhoeae utilizes OMVs to target PorB to mitochondria and to induce apoptosis in macrophages, thus affecting innate immunity. PMID:29601598

Debaryomyces hansenii: A Model System for Marine Molecular Biology

DTIC Science & Technology

1991-12-31

Gajadhar et al. 1991), Plasmodium berghei (Gunderson et al. 1986), Oytricha nova (Elwood et al. 1985), Paramecium terraurelia (Sogin and Elwood, 1986...berg J𔃾 Paramecium tenaurelia Dyctelioniiw discoideum 0.1 II -ifTorzdospra delbrueckii 52 Can&&d glabrata Saccharomyces cerevisiae 98 Kluyveromyces

Kazachstania Zubkova (1971)

USDA-ARS?s Scientific Manuscript database

This chapter describes the ascomycete yeast genus Kazachstania and is to be published in "The Yeasts, A Taxonomic Study, 5th edition." The genus Kazachstania is newly described and was constructed from certain species previously assigned to the genera Saccharomyces, Kluyveromyces and Arxozyma follo...

Gliding Motility and Por Secretion System Genes Are Widespread among Members of the Phylum Bacteroidetes

PubMed Central

Zhu, Yongtao

2013-01-01

The phylum Bacteroidetes is large and diverse, with rapid gliding motility and the ability to digest macromolecules associated with many genera and species. Recently, a novel protein secretion system, the Por secretion system (PorSS), was identified in two members of the phylum, the gliding bacterium Flavobacterium johnsoniae and the nonmotile oral pathogen Porphyromonas gingivalis. The components of the PorSS are not similar in sequence to those of other well-studied bacterial secretion systems. The F. johnsoniae PorSS genes are a subset of the gliding motility genes, suggesting a role for the secretion system in motility. The F. johnsoniae PorSS is needed for assembly of the gliding motility apparatus and for secretion of a chitinase, and the P. gingivalis PorSS is involved in secretion of gingipain protease virulence factors. Comparative analysis of 37 genomes of members of the phylum Bacteroidetes revealed the widespread occurrence of gliding motility genes and PorSS genes. Genes associated with other bacterial protein secretion systems were less common. The results suggest that gliding motility is more common than previously reported. Microscopic observations confirmed that organisms previously described as nonmotile, including Croceibacter atlanticus, “Gramella forsetii,” Paludibacter propionicigenes, Riemerella anatipestifer, and Robiginitalea biformata, exhibit gliding motility. Three genes (gldA, gldF, and gldG) that encode an apparent ATP-binding cassette transporter required for F. johnsoniae gliding were absent from two related gliding bacteria, suggesting that the transporter may not be central to gliding motility. PMID:23123910

Antigenic topology of chlamydial PorB protein and identification of targets for immune neutralization of infectivity.

PubMed

Kawa, Diane E; Stephens, Richard S

2002-05-15

The outer membrane protein PorB is a conserved chlamydial protein that functions as a porin and is capable of eliciting neutralizing Abs. A topological antigenic map was developed using overlapping synthetic peptides representing the Chlamydia trachomatis PorB sequence and polyclonal immune sera. To identify which antigenic determinants were surface accessible, monospecific antisera were raised to the PorB peptides and were used in dot-blot and ELISA-based absorption studies with viable chlamydial elementary bodies (EBs). The ability of the surface-accessible antigenic determinants to direct neutralizing Ab responses was investigated using standardized in vitro neutralization assays. Four major antigenic clusters corresponding to Phe(34)-Leu(59) (B1-2 and B1-3), Asp(112) -Glu(145) (B2-3 and B2-4), Gly(179)-Ala(225) (B3-2 to B3-4), and Val(261)-Asn(305) (B4-4 to B5-2) were identified. Collectively, the EB absorption and dot-blot assays established that the immunoreactive PorB Ags were exposed on the surface of chlamydial EBs. Peptide-specific antisera raised to the surface-accessible Ags neutralized chlamydial infectivity and demonstrated cross-reactivity to synthetic peptides representing analogous C. pneumoniae PorB sequences. Furthermore, neutralization of chlamydial infectivity by C. trachomatis PorB antisera was inhibited by synthetic peptides representing the surface-exposed PorB antigenic determinants. These findings demonstrate that PorB Ags may be useful for development of chlamydial vaccines.

Low oxygen environment facilitates embryo availability for older ovarian responders (PORs).

PubMed

Li, Mingzhao; Li, Zhibin; Shi, Juanzi

2018-04-18

We aimed to investigate the different effects of low oxygen (5% O 2 ) and atmospheric oxygen (20% O 2 ) on in vitro fertilization for older poor ovarian responders (PORs). We selected 1080 older PORs who met two criteria: (i) advanced maternal age (≥40) and (ii) an abnormal ovarian reserve test. All the patients used the ultra-short term protocols with GnRH agonist and recombinant FSH for controlled ovarian hyperstimulation (COH). About 506 cycles were performed in the incubators with 5% O 2 and 574 cycles were performed in the incubators with 20% O 2 . No significant differences were observed in normal fertilization rates (59.68 versus 60.25%; p = .691) and cancelation rates (18.97 versus 19.34%; p = .879) between two groups. The number of available embryos (1.77 ± 0.57 versus 1.52 ± 0.50; p = .041) and mean number of cells on Day 3 (7.49 ± 1.82 versus 7.16 ± 1.70; p = .032) were significantly higher in 5% O 2 group compared to that in 20% O 2 group. It showed no significant differences in the implantation rates (27.43 versus 24.11%; p = .803) and clinical pregnancy rates (36.34 versus 30.05%; p = .307) between two groups. The employ of low oxygen culture did not improve clinical pregnancy rate for older PORs. However, it benefited early embryonic development for older PORs.

Identification and assessment of kefir yeast potential for sugar/ethanol-resistance

PubMed Central

Miguel, M.G.C.P.; Cardoso, P.G.; Magalhães-Guedes, K.T.; Schwan, R.F.

2013-01-01

Biochemical and molecular analysis was used for identification of different kefir yeasts species from Brazil, Canada and the United States of America. The sugar/ethanol-resistant activity of the yeasts was evaluated. Saccharomyces cerevisiae and Kluyveromyces marxianus had the highest growth rates, suggesting biotechnological applications possible for these strains. PMID:24159292

Inversor Resonante de Tres Elementos L-LC con Caracteristica Cortocircuitable para Aplicaciones de Calentamiento por Induccion

NASA Astrophysics Data System (ADS)

Espi Huerta, Jose Miguel

Los generadores de calentamiento por induccion son puentes inversores con carga resonante, cuya mision es basicamente crear una corriente sinusoidal de gran amplitud sobre la "bobina de caldeo", que forma parte del tanque resonante. En el interior de esta bobina se introduce la pieza que se desea calentar. EI campo magnetico creado induce corrientes superficiales (corrientes de Foucault) sobre la pieza, que producen su calentamiento. Los tanques resonantes (tambien llamados osciladores) utilizados en la actualidad son el resonante serie y el resonante paralelo. Aunque ya desde hace algun tiempo se vienen construyendo generadores de alta potencia basados en estos dos osciladores, el exito nunca ha. sido completo en ninguno de los dos casos. Tal y como se explica en la introduccion de esta memoria, los puentes inversores utilizados deben operar sobre una carga inductiva (corriente retrasada) para evitar el fenomeno de la recuperacion inversa de sus diodos y la consiguiente ruptura de los transistores. De la restriccion topologica anterior se deduce que el generador paralelo debe conmutar a frecuencias inferiores a la resonancia, y el serie a frecuencias superiores. A esta restriccion topologica hay que unir otra que es exclusiva del calentamiento por induccion: La corriente por la bobina de caldeo debe ser sinusoidal. De no ser asi, resultaria imposible disponer toda la potencia de calentamiento sobre la pieza en el espesor requerido por la aplicacion. Como consecuencia, los inversores no pueden operar por debajo de la frecuencia de resonancia del oscilador, pues en ese caso se amplifican los armonicos de orden superior de la tension/corriente de entrada situados sobre la resonancia, con la consiguiente distorsion de la corriente de salida. La conjuncion de las dos restricciones anteriores obligan al inversor paralelo a funcionar a la frecuencia de resonancia del oscilador. Esto imposibilita un control por variacion de frecuencia, regulandose la potencia desde la

Yeast community in traditional Portuguese Serpa cheese by culture-dependent and -independent DNA approaches.

PubMed

Gonçalves Dos Santos, Maria Teresa P; Benito, María José; Córdoba, María de Guía; Alvarenga, Nuno; Ruiz-Moyano Seco de Herrera, Santiago

2017-12-04

This study investigated the yeast community present in the traditional Portuguese cheese, Serpa, by culture-dependent and -independent methods. Sixteen batches of Serpa cheeses from various regional industries registered with the Protected Designation of Origin (PDO) versus non-PDO registered, during spring and winter, were used. Irrespective of the producer, the yeast counts were around 5log CFU/g in winter and, overall, were lower in spring. The yeast species identified at the end of ripening (30days), using PCR-RFLP analysis and sequencing of the 26S rRNA, mainly corresponded to Debaryomyces hansenii and Kluyveromyces marxianus, with Candida spp. and Pichia spp. present to a lesser extent. The culture-independent results, obtained using high-throughput sequencing analysis, confirmed the prevalence of Debaryomyces spp. and Kluyveromyces spp. but, also, that Galactomyces spp. was relevant for three of the five producers, which indicates its importance during the early stages of the cheese ripening process, considering it was not found among the dominant viable yeast species. In addition, differences between the identified yeast isolated from cheeses obtained from PDO and non-PDO registered industries, showed that the lack of regulation of the cheese-making practice, may unfavourably influence the final yeast microbiota. The new knowledge provided by this study of the yeast diversity in Serpa cheese, could be used to modify the cheese ripening conditions, to favour desirable yeast species. Additionally, the prevalent yeast isolates identified, Debaryomyces hansenii and Kluyveromyces spp., may have an important role during cheese ripening and in the final sensorial characteristics. Thus, the study of their technological and functional properties could be relevant, in the development of an autochthonous starter culture, to ensure final quality and safety of the cheese. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of the yeast short-term Crabtree effect and its origin

PubMed Central

Hagman, Arne; Säll, Torbjörn; Piškur, Jure

2014-01-01

The short-term Crabtree effect is defined as the immediate occurrence of aerobic alcoholic fermentation in response to provision of a pulse of excess sugar to sugar-limited yeast cultures. Here we have characterized ten yeast species with a clearly defined phylogenetic relationship. Yeast species were cultivated under glucose-limited conditions, and we studied their general carbon metabolism in response to a glucose pulse. We generated an extensive collection of data on glucose and oxygen consumption, and ethanol and carbon dioxide generation. We conclude that the Pichia,Debaryomyces,Eremothecium and Kluyveromyces marxianus yeasts do not exhibit any significant ethanol formation, while Kluyveromyces lactis behaves as an intermediate yeast, and Lachancea,Torulaspora,Vanderwaltozyma and Saccharomyces yeasts exhibit rapid ethanol accumulation. Based on the present data and our previous data relating to the presence of the long-term Crabtree effect in over 40 yeast species, we speculate that the origin of the short-term effect may coincide with the origin of the long-term Crabtree effect in the Saccharomycetales lineage, occurring ∼ 150 million years ago. PMID:25161062

Multiple active site residues are important for photochemical efficiency in the light-activated enzyme protochlorophyllide oxidoreductase (POR).

PubMed

Menon, Binuraj R K; Hardman, Samantha J O; Scrutton, Nigel S; Heyes, Derren J

2016-08-01

Protochlorophyllide oxidoreductase (POR) catalyzes the light-driven reduction of protochlorophyllide (Pchlide), an essential, regulatory step in chlorophyll biosynthesis. The unique requirement of the enzyme for light has provided the opportunity to investigate how light energy can be harnessed to power biological catalysis and enzyme dynamics. Excited state interactions between the Pchlide molecule and the protein are known to drive the subsequent reaction chemistry. However, the structural features of POR and active site residues that are important for photochemistry and catalysis are currently unknown, because there is no crystal structure for POR. Here, we have used static and time-resolved spectroscopic measurements of a number of active site variants to study the role of a number of residues, which are located in the proposed NADPH/Pchlide binding site based on previous homology models, in the reaction mechanism of POR. Our findings, which are interpreted in the context of a new improved structural model, have identified several residues that are predicted to interact with the coenzyme or substrate. Several of the POR variants have a profound effect on the photochemistry, suggesting that multiple residues are important in stabilizing the excited state required for catalysis. Our work offers insight into how the POR active site geometry is finely tuned by multiple active site residues to support enzyme-mediated photochemistry and reduction of Pchlide, both of which are crucial to the existence of life on Earth. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

VERA-CS User Support Activities for PoR 14

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kochunas, Brendan

2017-11-01

The purpose of this milestone is to document the user support activities that took place between 10/1/2016 and 3/31/2017 (PoR 14). In the normal PHI workflow, that also extends to several activities within RTM, a Kanban process is followed. This involves creating tickets for specific work items and track the progress to complete these specific work items.

Utilization of inulin-containing waste in industrial fermentations to produce biofuels and bio-based chemicals.

PubMed

Hughes, Stephen R; Qureshi, Nasib; López-Núñez, Juan Carlos; Jones, Marjorie A; Jarodsky, Joshua M; Galindo-Leva, Luz Ángela; Lindquist, Mitchell R

2017-04-01

Inulins are polysaccharides that belong to an important class of carbohydrates known as fructans and are used by many plants as a means of storing energy. Inulins contain 20 to several thousand fructose units joined by β-2,1 glycosidic bonds, typically with a terminal glucose unit. Plants with high concentrations of inulin include: agave, asparagus, coffee, chicory, dahlia, dandelion, garlic, globe artichoke, Jerusalem artichoke, jicama, onion, wild yam, and yacón. To utilize inulin as its carbon and energy source directly, a microorganism requires an extracellular inulinase to hydrolyze the glycosidic bonds to release fermentable monosaccharides. Inulinase is produced by many microorganisms, including species of Aspergillus, Kluyveromyces, Penicillium, and Pseudomonas. We review various inulinase-producing microorganisms and inulin feedstocks with potential for industrial application as well as biotechnological efforts underway to develop sustainable practices for the disposal of residues from processing inulin-containing crops. A multi-stage biorefinery concept is proposed to convert cellulosic and inulin-containing waste produced at crop processing operations to valuable biofuels and bioproducts using Kluyveromyces marxianus, Yarrowia lipolytica, Rhodotorula glutinis, and Saccharomyces cerevisiae as well as thermochemical treatments.

Yeast Diversity and Persistence in Botrytis-Affected Wine Fermentations

PubMed Central

Mills, David A.; Johannsen, Eric A.; Cocolin, Luca

2002-01-01

Culture-dependent and -independent methods were used to examine the yeast diversity present in botrytis-affected (“botrytized”) wine fermentations carried out at high (∼30°C) and ambient (∼20°C) temperatures. Fermentations at both temperatures possessed similar populations of Saccharomyces, Hanseniaspora, Pichia, Metschnikowia, Kluyveromyces, and Candida species. However, higher populations of non-Saccharomyces yeasts persisted in ambient-temperature fermentations, with Candida and, to a lesser extent, Kluyveromyces species remaining long after the fermentation was dominated by Saccharomyces. In general, denaturing gradient gel electrophoresis profiles of yeast ribosomal DNA or rRNA amplified from the fermentation samples correlated well with the plating data. The direct molecular methods also revealed a Hanseniaspora osmophila population not identified in the plating analysis. rRNA analysis also indicated a large population (>106 cells per ml) of a nonculturable Candida strain in the high-temperature fermentation. Monoculture analysis of the Candida isolate indicated an extreme fructophilic phenotype and correlated with an increased glucose/fructose ratio in fermentations containing higher populations of Candida. Analysis of wine fermentation microbial ecology by using both culture-dependent and -independent methods reveals the complexity of yeast interactions enriched during spontaneous fermentations. PMID:12324335

A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements.

PubMed Central

D'Souza-Schorey, C; Boshans, R L; McDonough, M; Stahl, P D; Van Aelst, L

1997-01-01

The ARF6 GTPase, the least conserved member of the ADP ribosylation factor (ARF) family, associates with the plasma membrane and intracellular endosome vesicles. Mutants of ARF6 defective in GTP binding and hydrolysis have a marked effect on endocytic trafficking and the gross morphology of the peripheral membrane system. Here we report that expression of the GTPase-defective mutant of ARF6, ARF6(Q67L), remodels the actin cytoskeleton by inducing actin polymerization at the cell periphery. This cytoskeletal rearrangement was inhibited by co-expression of ARF6(Q67L) with deletion mutants of POR1, a Rac1-interacting protein involved in membrane ruffling, but not with the dominant-negative mutant of Rac1, Rac1(S17N). A synergistic effect between POR1 and ARF6 for the induction of actin polymerization was detected. Furthermore, we observed that ARF6 interacts directly with POR1 and that this interaction was GTP dependent. These findings indicate that ARF6 and Rac1 function on distinct signaling pathways to mediate cytoskeletal reorganization, and suggest a role for POR1 as an important regulatory element in orchestrating cytoskeletal rearrangements at the cell periphery induced by ARF6 and Rac1. PMID:9312003

Effect of SPM-based cleaning POR on EUV mask performance

NASA Astrophysics Data System (ADS)

Choi, Jaehyuck; Lee, Han-shin; Yoon, Jinsang; Shimomura, Takeya; Friz, Alex; Montgomery, Cecilia; Ma, Andy; Goodwin, Frank; Kang, Daehyuk; Chung, Paul; Shin, Inkyun; Cho, H.

2011-11-01

EUV masks include many different layers of various materials rarely used in optical masks, and each layer of material has a particular role in enhancing the performance of EUV lithography. Therefore, it is crucial to understand how the mask quality and patterning performance can change during mask fabrication, EUV exposure, maintenance cleaning, shipping, or storage. The fact that a pellicle is not used to protect the mask surface in EUV lithography suggests that EUV masks may have to undergo more cleaning cycles during their lifetime. More frequent cleaning, combined with the adoption of new materials for EUV masks, necessitates that mask manufacturers closely examine the performance change of EUV masks during cleaning process. We have investigated EUV mask quality and patterning performance during 30 cycles of Samsung's EUV mask SPM-based cleaning and 20 cycles of SEMATECH ADT exposure. We have observed that the quality and patterning performance of EUV masks does not significantly change during these processes except mask pattern CD change. To resolve this issue, we have developed an acid-free cleaning POR and substantially improved EUV mask film loss compared to the SPM-based cleaning POR.

Detección y estudio mediante Fluorescencia Inducida por Láser de radicales libres formados por Disociación Multifotónica Infrarroja

NASA Astrophysics Data System (ADS)

Santos, M.; Díaz, L.; Torresano, J. A.; Rubio, L.; Samoudi, B.

Una de las principales aplicaciones actuales de los procesos de disociación multifotónica inducidos por radiación láser infrarroja (DMI) es la producción de radiales libres, con el fin de estudiar sus propiedades cinéticas y espectroscópicas. La disociación de moléculas poliatómicas en el IR con láseres de CO2 tiene lugar desde la superficie de energía molecular mas baja y conduce generalmente a la formación de fragmentos en el estado electrónico fundamental, con diversos grados de excitación vibracional. En el Grupo de Procesos Multifotónicos del Instituto de Estructura de la Materia del C.S.I.C. hemos puesto a punto la técnica de Fluorescencia Inducida por Láser (LIF) para la detección y análisis en tiempo real de los fragmentos producidos en la DMI inducida mediante uno o dos campos láseres de diferentes longitudes de onda. Objetivos de nuestro trabajo han sido el estudio de los canales de disociación mayoritarios y de las especies transitoria producidas, así como de la distribución de energía interna con que éstas son generadas. En particular hemos detectado mediante LIF las especies: C2, CF, CH, SiH2, CF2, CH2, SiHCl, y CF3 a partir de la disociación de, entre otras, las siguientes moléculas: C2H3Br, C3F6, C4H8Si, C2H5ClSi y CH5ClSi. En este trabajo presentamos algunos de los resultados obtenidos mediante el estudio por LIF de estos radicales: estudio temporal de la señal LIF obtenida con determinación de tiempos de vida, espectros de excitación y fluorescencia, temperaturas vibracionales de formación, variación de la intensidad LIF con el tiempo de retraso entre los láseres de disociación y prueba, etc.

Determinacion del error sistematico del momentum de muones producidos por interacciones neutrino-nucleon en el detector MINER$$\

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz Bautista, Gonzalo A.

El Modelo Estandar describe todas las partculas observadas en el naturaleza hasta el momento as como las caractersticas que gobiernan a las interacciones fundamentales entre ellas. En especial es posible identicar a las interacciones electromagnetica y debil, las cuales bajo determinadas condiciones de temperatura y energa pueden ser descritas a traves de una sola teora que engloba a ambas. A esta teora se le denomina electrodebil y tiene como nalidad caracterizar las propiedades de la interaccion maniesta a partir de la mezcla de las interacciones electromagnetica y debil, la que tambien lleva como nombre interaccion electrodebil. Particularmente, los neutrinos sonmore » de especial interes ya que, por un lado, interactuan por medio de la interaccion debil muy raramente en comparacion con otras partculas y, por el otro, no son acertadamente descritos por el Modelo Estandar. Por medio de observaciones experimentales que demostraban que los neutrinos cambian de sabor al propagarse, fenomeno llamado oscilaciones de neutrinos, se pudo llegar a la conclusion de que la implicancia de este fenomeno da como consecuencia que los neutrinos efectivamente s tienen masa, algo que entra en contradiccion con la descripcion inicial del Modelo Estandar, el cual los describe como partculas sin masa. Es de esta manera que las oscilaciones de neutrinos han sido y siguen siendo en la actualidad objeto de interes en la Fsica de Altas Energas tanto teorica como experimental. A n de poder realizar mediciones precisas de oscilaciones de neutrinos, los experimentos encargados de estas mediciones deben tratar de reducir sus incertidumbres en lo posible. Una de estas proviene de la caracterizacion de las secciones de choque de los neutrinos cuando interactuan con la materia, particularmente los nucleones al interior de los nucleos atomicos. El experimento MINERA esta orientado, entre otras cosas, a hacer una correcta caracterizacion de secciones de choque neutrino-nucleon por medio del

Mapping the Laminin Receptor Binding Domains of Neisseria meningitidis PorA and Haemophilus influenzae OmpP2

PubMed Central

Mahdavi, Jafar; Oldfield, Neil J.; Wheldon, Lee M.; Wooldridge, Karl G.; Ala'Aldeen, Dlawer A. A.

2012-01-01

Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae are major bacterial agents of meningitis. They each bind the 37/67-kDa laminin receptor (LamR) via the surface protein adhesins: meningococcal PilQ and PorA, H. influenzae OmpP2 and pneumococcal CbpA. We have previously reported that a surface-exposed loop of the R2 domain of CbpA mediates LamR-binding. Here we have identified the LamR-binding regions of PorA and OmpP2. Using truncated recombinant proteins we show that binding is dependent on amino acids 171–240 and 91–99 of PorA and OmpP2, respectively, which are predicted to localize to the fourth and second surface-exposed loops, respectively, of these proteins. Synthetic peptides corresponding to the loops bound LamR and could block LamR-binding to bacterial ligands in a dose dependant manner. Meningococci expressing PorA lacking the apex of loop 4 and H. influenzae expressing OmpP2 lacking the apex of loop 2 showed significantly reduced LamR binding. Since both loops are hyper-variable, our data may suggest a molecular basis for the range of LamR-binding capabilities previously reported among different meningococcal and H. influenzae strains. PMID:23049988

Mapping the laminin receptor binding domains of Neisseria meningitidis PorA and Haemophilus influenzae OmpP2.

PubMed

Abouseada, Noha M; Assafi, Mahde Saleh A; Mahdavi, Jafar; Oldfield, Neil J; Wheldon, Lee M; Wooldridge, Karl G; Ala'Aldeen, Dlawer A A

2012-01-01

Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae are major bacterial agents of meningitis. They each bind the 37/67-kDa laminin receptor (LamR) via the surface protein adhesins: meningococcal PilQ and PorA, H. influenzae OmpP2 and pneumococcal CbpA. We have previously reported that a surface-exposed loop of the R2 domain of CbpA mediates LamR-binding. Here we have identified the LamR-binding regions of PorA and OmpP2. Using truncated recombinant proteins we show that binding is dependent on amino acids 171-240 and 91-99 of PorA and OmpP2, respectively, which are predicted to localize to the fourth and second surface-exposed loops, respectively, of these proteins. Synthetic peptides corresponding to the loops bound LamR and could block LamR-binding to bacterial ligands in a dose dependant manner. Meningococci expressing PorA lacking the apex of loop 4 and H. influenzae expressing OmpP2 lacking the apex of loop 2 showed significantly reduced LamR binding. Since both loops are hyper-variable, our data may suggest a molecular basis for the range of LamR-binding capabilities previously reported among different meningococcal and H. influenzae strains.

Trombocitopenia induzida por heparina em paciente com oclusão arterial aguda

PubMed Central

Pimenta, Rafael Elias Farres; Yoshida, Winston Bonetti; Rollo, Hamilton Almeida; Sobreira, Marcone Lima; Bertanha, Matheus; Mariúba, Jamil Victor de Oliveira; Jaldin, Rodrigo Gibin; de Camargo, Paula Angeleli Bueno

2016-01-01

Resumo A trombocitopenia induzida por heparina é uma complicação grave da terapêutica anticoagulante com heparina e está associada à formação de anticorpos antifator IV plaquetário. Costuma surgir a partir do quinto dia do tratamento, com queda de pelo menos 50% da contagem plaquetária. Em decorrência da ativação plaquetária concomitante, pode ocorrer quadro de trombose, venosa ou arterial, com repercussões clínicas graves. Apresentamos um caso de paciente portador de síndrome do anticorpo antifosfolípide, com quadro de oclusão arterial aguda, que foi tratado cirurgicamente e recebeu heparina não fracionada no intra e pós-operatório. No quinto dia de tratamento anticoagulante, apresentou queda maior de 50% da contagem de plaquetas em relação à contagem pré-heparina. A suspeita de trombocitopenia induzida por heparina e seus aspectos diagnósticos e terapêuticos serão abordados neste desafio terapêutico.

Prevalencia y tamizaje del Trastorno por Déficit de Atención con Hiperactividad en Costa Rica

PubMed Central

Weiss, Nicholas T.; Schuler, Jovita; Monge, Silvia; McGough, James J.; Chavira, Denise; Bagnarello, Monica; Herrera, Luis Diego; Mathews, Carol A.

2015-01-01

Resumen La investigación tuvo como propósito estimar la prevalencia del Trastorno por Déficit de Atención con Hiperactividad (TDAH) en Costa Rica y determinar si la versión en español del cuestionario Swanson Nolan and Pelham Scale IV (SNAP-IV) es un instrumento de tamizaje útil en una población de niños y niñas escolares costarricenses. El instrumento fue entregado a padres y maestros de 425 niños entre 5 y 13 años de edad (promedio = 8.8). Todos fueron evaluados con el instrumento Swanson, Kotkin, Agler, M-Flynn and Pelham Scale (SKAMP). Su diagnóstico fue confirmado con una entrevista clínica. La sensibilidad y la especificidad del SNAP-IV fueron evaluadas como predictores de criterios de diagnóstico según el DSM-IV. La prevalencia puntual en la muestra del TDAH fue del 5%. El tamizaje más preciso lo hizo el SNAP-IV completado por el maestro en un corte de 20%, con una sensibilidad de 96% y una especificidad de un 82%. La sensibilidad de los instrumentos completados por los padres fue más baja que aquella de los maestros. El SNAP-IV completado por las maestras con un corte aislando el 20% de los mayores puntajes categorizó correctamente a un 87% de los sujetos. PMID:22432094

Racism in digital era: Development and initial validation of the Perceived Online Racism Scale (PORS v1.0).

PubMed

Keum, Brian TaeHyuk; Miller, Matthew J

2017-04-01

The purpose of this study was to develop the Perceived Online Racism Scale (PORS) to assess perceived online racist interpersonal interactions and exposure to online racist content among people of color. Items were developed through a multistage process involving a comprehensive literature review, focus-groups, qualitative data collection, and survey of online racism experiences. Based on a sample of 1,023 racial minority participants, exploratory and confirmatory factor analyses provided support for a 30-item bifactor model accounted by the general factor and the following 3 specific factors: (a) personal experience of racial cyber-aggression, (b) vicarious exposure to racial cyber-aggression, and (c) online-mediated exposure to racist reality. The PORS demonstrated measurement invariance across racial/ethnic groups in our sample. Internal reliability estimates for the total and subscale scores of the PORS were above .88 and the 4-week test-retest reliability was adequate. Limitations and future directions for research are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

[Professor Frantisek Por MD and Professor Robert Klopstock MD, students at Budapest and Prague Faculties of Medicine].

PubMed

Mydlík, M; Derzsiová, K

2010-11-01

Professor Frantisek Por MD and Professor Robert Klopstock MD were contemporaries, both born in 1899, one in Zvolen, the other in Dombovar, at the time of Austro-Hungarian Monarchy. Prof. Por attended the Faculty of Medicine in Budapest from 1918 to 1920, and Prof. Klopstock studied at the same place between 1917 and 1919. From 1920 until graduation on 6th February 1926, Prof. Por continued his studies at the German Faculty of Medicine, Charles University in Prague. Prof. Klopstock had to interrupt his studies in Budapest due to pulmonary tuberculosis; he received treatment at Tatranske Matliare where he befriended Franz Kafka. Later, upon Kafka's encouragement, he changed institutions and continued his studies at the German Faculty of Medicine, Charles University in Prague, where he graduated the first great go. It is very likely that, during their studies in Budapest and Prague, both professors met repeatedly, even though their life paths later separated. Following his graduation, Prof. Por practiced as an internist in Prague, later in Slovakia, and from 1945 in Kosice. In 1961, he was awarded the title of university professor of internal medicine at the Faculty of Medicine, Pavol Jozef Safarik University in Kosice, where he practiced until his death in 1980. Prof. Klopstock continued his studies in Kiel and Berlin. After his graduation in 1933, he practiced in Berlin as a surgeon and in 1938 left for USA. In 1962, he was awarded the title of university professor of pulmonary surgery in NewYork, where he died in 1972.

Pilot scale fermentation of Jerusalem artichoke tuber pulp mashes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziobro, G.C.; Williams, L.A.

1983-01-01

Processing and fermentation of Jerusalem artichoke (Helianthus tuberosus L.) tuber pulp mashes were successfully carried out at pilot scales of 60 gallons and 1000 gallons. Whole tubers were pulped mechanically into a thick mash and fermented, using commercially available Saccharomyces cerevisiae and selected strains of Kluyveromyces fragilis. EtOH fermentation yields ranging from 50-70% of theoretical maximum were obtained in 3-4 days. Several problems regarding the processing and direct fermentation of tuber pulp mashes are discussed.

Encefalitis por anticuerpos contra el receptor de NMDA: experiencia con seis pacientes pediátricos. Potencial eficacia del metotrexato

PubMed Central

Bravo-Oro, Antonio; Abud-Mendoza, Carlos; Quezada-Corona, Arturo; Dalmau, Josep; Campos-Guevara, Verónica

2016-01-01

Introducción La encefalitis por anticuerpos contra el receptor de N-metil-D-aspartato (NMDA) es una entidad cada vez más diagnosticada en edad pediátrica. A diferencia de los adultos, en muchos casos no se asocia a tumores y las manifestaciones iniciales en niños más frecuentes son crisis convulsivas y trastornos del movimiento, mientras que en los adultos predominan las alteraciones psiquiátricas. Casos clínicos Presentamos seis casos pediátricos confirmados con anticuerpos contra la subunidad NR1 del receptor de NMDA en suero y líquido cefalorraquídeo. Cinco de los casos comenzaron con crisis convulsivas como manifestación clínica inicial antes de desarrollar el cuadro clásico de esta entidad. En todos los casos se utilizaron esteroides como primera línea de tratamiento, con los que sólo se observó control de las manifestaciones en uno, por lo que el resto de los pacientes requirió inmunomoduladores de segunda línea. Todos los pacientes recibieron metotrexato como tratamiento inmunomodulador para evitar recaídas y la evolución fue a la mejoría en todos ellos. Conclusiones En nuestra serie de pacientes con encefalitis por anticuerpos contra el receptor de NMDA, ninguno se asoció a tumores. Todos los casos recibieron metotrexato por lo menos durante un año, no observamos eventos adversos clínicos ni por laboratorio, ni hubo secuelas neurológicas ni recaídas durante el tratamiento. Aunque es una serie pequeña y es deseable incrementar el número y tiempo de evolución, consideramos el metotrexato una excelente alternativa como tratamiento inmunomodulador para esta patología. PMID:24150952

Structural and functional probing of PorZ, an essential bacterial surface component of the type-IX secretion system of human oral-microbiomic Porphyromonas gingivalis.

PubMed Central

Lasica, Anna M.; Goulas, Theodoros; Mizgalska, Danuta; Zhou, Xiaoyan; de Diego, Iñaki; Ksiazek, Mirosław; Madej, Mariusz; Guo, Yonghua; Guevara, Tibisay; Nowak, Magdalena; Potempa, Barbara; Goel, Apoorv; Sztukowska, Maryta; Prabhakar, Apurva T.; Bzowska, Monika; Widziolek, Magdalena; Thøgersen, Ida B.; Enghild, Jan J.; Simonian, Mary; Kulczyk, Arkadiusz W.; Nguyen, Ky-Anh; Potempa, Jan; Gomis-Rüth, F. Xavier

2016-01-01

Porphyromonas gingivalis is a member of the human oral microbiome abundant in dysbiosis and implicated in the pathogenesis of periodontal (gum) disease. It employs a newly described type-IX secretion system (T9SS) for secretion of virulence factors. Cargo proteins destined for secretion through T9SS carry a recognition signal in the conserved C-terminal domain (CTD), which is removed by sortase PorU during translocation. Here, we identified a novel component of T9SS, PorZ, which is essential for surface exposure of PorU and posttranslational modification of T9SS cargo proteins. These include maturation of enzyme precursors, CTD removal and attachment of anionic lipopolysaccharide for anchorage in the outer membrane. The crystal structure of PorZ revealed two β-propeller domains and a C-terminal β-sandwich domain, which conforms to the canonical CTD architecture. We further documented that PorZ is itself transported to the cell surface via T9SS as a full-length protein with its CTD intact, independently of the presence or activity of PorU. Taken together, our results shed light on the architecture and possible function of a novel component of the T9SS. Knowledge of how T9SS operates will contribute to our understanding of protein secretion as part of host-microbiome interactions by dysbiotic members of the human oral cavity. PMID:27883039

The enhanced immune responses induced by Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porB against Salmonella in mice.

PubMed

Jiao, Hongmei; Yang, Hui; Zhao, Dan; He, Li; Chen, Jin; Li, Guocai

2016-11-01

Human health has been seriously endangered by highly prevalent salmonellosis and multidrug-resistant Salmonella strains. Current vaccines suffer from variable immune-protective effects, so more effective ones are needed to control Salmonella infection : Bacterial ghosts have been produced by the expression of lysis gene E from bacteriophage PhiX174 and can be filled with considerable exogenous substances such as DNA or drugs as a novel platform. In this study, Salmonella enteritidis (SE) ghosts were developed and loaded with Neisseria gonorrhoeae porin B (porB) to construct a novel inactive vaccine. Our new studies show that SE ghosts loaded with porB displayed increased production of pro-inflammatory cytokines (IL-1β, IL-6, IL-10 and IL-12p70) in bone marrow-derived dendritic cells (BMDCs), and elicited significantly higher specific systemic and mucosal immune responses to Salmonella than SE ghosts alone. In addition, the novel porB-loaded ghosts conferred higher protective effects on virulent Salmonella challenge. For the first time, we demonstrate that N. gonorrhoeae porB, as a novel adjuvant, can increase the immunogenicity of SE ghosts. Our studies suggested that Salmonella enteritidis ghosts loaded with Neisseria gonorrhoeae porin B might be a useful mucosal Salmonella vaccine candidate for practical use in the future. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A surprisingly large RNase P RNA in Candida glabrata

PubMed Central

KACHOURI, RYM; STRIBINSKIS, VILIUS; ZHU, YANGLONG; RAMOS, KENNETH S.; WESTHOF, ERIC; LI, YONG

2005-01-01

We have found an extremely large ribonuclease P (RNase P) RNA (RPR1) in the human pathogen Candida glabrata and verified that this molecule is expressed and present in the active enzyme complex of this hemiascomycete yeast. A structural alignment of the C. glabrata sequence with 36 other hemiascomycete RNase P RNAs (abbreviated as P RNAs) allows us to characterize the types of insertions. In addition, 15 P RNA sequences were newly characterized by searching in the recently sequenced genomes Candida albicans, C. glabrata, Debaryomyces hansenii, Eremothecium gossypii, Kluyveromyces lactis, Kluyveromyces waltii, Naumovia castellii, Saccharomyces kudriavzevii, Saccharomyces mikatae, and Yarrowia lipolytica; and by PCR amplification for other Candida species (Candida guilliermondii, Candida krusei, Candida parapsilosis, Candida stellatoidea, and Candida tropicalis). The phylogenetic comparative analysis identifies a hemiascomycete secondary structure consensus that presents a conserved core in all species with variable insertions or deletions. The most significant variability is found in C. glabrata P RNA in which three insertions exceeding in total 700 nt are present in the Specificity domain. This P RNA is more than twice the length of any other homologous P RNAs known in the three domains of life and is eight times the size of the smallest. RNase P RNA, therefore, represents one of the most diversified noncoding RNAs in terms of size variation and structural diversity. PMID:15987816

The RNA polymerase III-dependent family of genes in hemiascomycetes: comparative RNomics, decoding strategies, transcription and evolutionary implications

PubMed Central

Marck, Christian; Kachouri-Lafond, Rym; Lafontaine, Ingrid; Westhof, Eric; Dujon, Bernard; Grosjean, Henri

2006-01-01

We present the first comprehensive analysis of RNA polymerase III (Pol III) transcribed genes in ten yeast genomes. This set includes all tRNA genes (tDNA) and genes coding for SNR6 (U6), SNR52, SCR1 and RPR1 RNA in the nine hemiascomycetes Saccharomyces cerevisiae, Saccharomyces castellii, Candida glabrata, Kluyveromyces waltii, Kluyveromyces lactis, Eremothecium gossypii, Debaryomyces hansenii, Candida albicans, Yarrowia lipolytica and the archiascomycete Schizosaccharomyces pombe. We systematically analysed sequence specificities of tRNA genes, polymorphism, variability of introns, gene redundancy and gene clustering. Analysis of decoding strategies showed that yeasts close to S.cerevisiae use bacterial decoding rules to read the Leu CUN and Arg CGN codons, in contrast to all other known Eukaryotes. In D.hansenii and C.albicans, we identified a novel tDNA-Leu (AAG), reading the Leu CUU/CUC/CUA codons with an unusual G at position 32. A systematic ‘p-distance tree’ using the 60 variable positions of the tRNA molecule revealed that most tDNAs cluster into amino acid-specific sub-trees, suggesting that, within hemiascomycetes, orthologous tDNAs are more closely related than paralogs. We finally determined the bipartite A- and B-box sequences recognized by TFIIIC. These minimal sequences are nearly conserved throughout hemiascomycetes and were satisfactorily retrieved at appropriate locations in other Pol III genes. PMID:16600899

Diagnóstico diferencial en la encefalitis por anticuerpos contra el receptor NMDA

PubMed Central

González-Valcárcel, J.; Rosenfeld, M.R.; Dalmau, J.

2011-01-01

Resumen Introducción La encefalitis por anticuerpos contra el receptor de NMDA (NMDAR) suele desarrollarse como un síndrome característico de evolución multifásica y diagnóstico diferencial amplio. Pacientes Presentamos a 2 pacientes diagnosticadas de encefalitis por anticuerpos NMDAR con un cuadro clínico típico, pero que inicialmente señaló otras etiologías. Discusión La afectación frecuente de pacientes jóvenes con manifestaciones psiquiátricas prominentes indica frecuentemente otras consideraciones diagnósticas; las más frecuentes son las encefalitis virales, los procesos psiquiátricos y el síndrome neuroléptico maligno. Varios síndromes previamente definidos de manera parcial o descriptiva en adultos y pacientes pediátricos probablemente eran casos de encefalitis anti-NMDAR. Conclusiones La encefalitis anti-NMDAR debe considerarse en pacientes jóvenes con manifestaciones psiquiátricas subagudas, movimientos anormales y alteraciones autonómicas. La caracterización clínica e inmunológica de esta enfermedad ha llevado a la identificación de nuevos anticuerpos que afectan a procesos de memoria, aprendizaje, conducta y psicosis. PMID:20964986

Feasibility of biohydrogen production from industrial wastes using defined microbial co-culture.

PubMed

Chen, Peng; Wang, Yuxia; Yan, Lei; Wang, Yiqing; Li, Suyue; Yan, Xiaojuan; Wang, Ningbo; Liang, Ning; Li, Hongyu

2015-05-06

The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth) was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth). Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium). Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 mL/h(-1).L(-1), and those the two

Yeasts from autochthonal cheese starters: technological and functional properties.

PubMed

Binetti, A; Carrasco, M; Reinheimer, J; Suárez, V

2013-08-01

The aim of this work was to identify 20 yeasts isolated from autochthonal cheese starters and evaluate their technological and functional properties. The capacities of the yeasts to grow at different temperatures, pH, NaCl and lactic acid concentrations as well as the proteolytic and lipolytic activities were studied. Moreover, survival to simulated gastrointestinal digestion, hydrophobicity, antimicrobial activity against pathogens and auto- and co-aggregation abilities were evaluated. The sequentiation of a fragment from the 26S rDNA gene indicated that Kluyveromyces marxianus was the predominant species, followed by Saccharomyces cerevisiae, Clavispora lusitaniae, Kluyveromyces lactis and Galactomyces geotrichum. RAPD with primer M13 allowed a good differentiation among strains from the same species. All strains normally grew at pH 4.7-5.5 and temperatures between 15 and 35°C. Most of them tolerated 10% NaCl and 3% lactic acid. Some strains showed proteolytic (eight isolates) and/or lipolytic (four isolates) capacities. All strains evidenced high gastrointestinal resistance, moderate hydrophobicity, intermediate auto-aggregation and variable co-aggregation abilities. No strains inhibited the growth of the pathogens assayed. Some strains from dairy sources showed interesting functional and technological properties. This study has been the first contribution to the identification and characterization of yeasts isolated from autochthonal cheese starters in Argentina. Many strains could be proposed as potential candidates to be used as probiotics and/or as co-starters in cheese productions. © 2013 The Society for Applied Microbiology.

Reconstrução tridimensional de arcos magnéticos por tomografia

NASA Astrophysics Data System (ADS)

Simões, P. J. A.; Costa, J. E. R.

2003-08-01

Uma explosão solar é uma variação súbita do brilho que ocorre nas regiões ativas da atmosfera solar. Estas regiões são constituídas por um plasma magnetizado com intensa indução magnética e em cenários bem complexos como visto recentemente através de experimentos embarcados em satélites operando instrumentos em raios X moles e ultra-violeta distante. A energia magnética, que pode ser armazenada por um período de horas até dias em configurações magnéticas estressadas, é subitamente lançada na atmosfera solar e transferida para partículas como elétrons, prótons e núcleos pesados, que são acelerados e/ou aquecidos, produzindo radiação eletromagnética. A proposta final deste projeto é determinar as características espaciais de alta resolução da emissão e polarização girossincrotrônica de explosões solares em ambientes complexos de campos magnéticos. Os recentes resultados da emissão difusa em EUV apresentado pelos satélites TRACE e SOHO dos arcos magnéticos conectando as diferentes polaridades magnéticas sobre as regiões ativas possibilitam novas abordagens sobre o papel do campo magnético na emissão em rádio. Nesta etapa apresentamos os resultados da reconstrução da geometria tridimensional das linhas de força destes arcos utilizando técnicas tomográficas, a partir de imagens de alta resolução espacial obtidas pelo instrumento EIT (Extreme ultraviolet Imaging Telescope), além da modelagem das induções magnéticas por um campo dipolar e as densidades de partículas aceleradas. Utilizamos para a reconstrução geométrica, imagens tomadas em vários ângulos dos arcos devido à rotacão solar. Com estes resultados, daremos continuidade ao projeto, com os cálculos da transferência radiativa nos modos ordinário e extraordinário de propagação da radiação girossincrotrônica de explosões solares.

The Acquisition of Lexical Meaning in a Study Abroad Context: The Spanish Prepositions "por" and "para."

ERIC Educational Resources Information Center

Lafford, Barbara A.; Ryan, John M.

1995-01-01

Examination of the development of form/function relations of the prepositions "por" and "para" at different levels of proficiency in the interlanguage of study-abroad students in Granada, Spain, revealed "noncanonical" as well as "canonical" uses of these prepositions. The most common noncanonical uses were…

PMAA-stabilized ferrofluid/chitosan/yeast composite for bioapplications

NASA Astrophysics Data System (ADS)

Baldikova, Eva; Prochazkova, Jitka; Stepanek, Miroslav; Hajduova, Jana; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

2017-04-01

A simple, one-pot process for the preparation of magnetically responsive yeast-based biocatalysts was developed. Saccharomyces cerevisiae, Candida utilis and Kluyveromyces lactis cells were successfully incorporated into chitosan gel magnetically modified with poly(methacrylic acid)-stabilized magnetic fluid (PMAA-FF) during its formation. Magnetic PMAA-FF/chitosan/yeast composites were efficiently employed for invert sugar production. The dependence of invertase activity on used yeast, amount of magnetic biocatalyst, agitation time and after reuse was studied in detail. The tested magnetic biocatalysts retained at least 69% of their initial activity after 8 reuse cycles.

Improved purification of native meningococcal porin PorB and studies on its structure/function.

PubMed

Massari, Paola; King, Carol A; MacLeod, Heather; Wetzler, Lee M

2005-12-01

The outer membrane protein PorB of Neisseria meningitidis is a pore-forming protein which has various effects on eukaryotic cells. It has been shown to (1) up-regulate the surface expression of the co-stimulatory molecule CD86 and of MHC class II (which are TLR2/MyD88 dependent and related to the porin's immune-potentiating ability), (2) be involved in prevention of apoptosis by modulating the mitochondrial membrane potential, and (3) form pores in eukaryotic cells. As an outer membrane protein, its native trimeric form isolation is complicated by its insoluble nature, requiring the presence of detergent throughout the whole procedure, and by its tight association with other outer membrane components, such as neisserial LOS or lipoproteins. In this study, an improved chromatographic purification method to obtain an homogeneous product free of endotoxin and lipoprotein is described, without loss of any of the above-mentioned properties of the porin. Furthermore, we have investigated the requirement of the native trimeric structure for the porin's activity. Inactivation of functional PorB trimers into non-functional monomers was achieved by incubation on ice. Thus, routine long- and medium-term storage at low temperature may be a cause of porin inactivation.

21 CFR 184.1388 - Lactase enzyme preparation from Kluyveromyces lactis.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-galactoside galactohydrase (CAS Reg. No. CBS 683), which converts lactose to glucose and galactose. It is... in § 170.3(o)(9) of this chapter to convert lactose to glucose and galactose. (2) The ingredient is... practice is to use this ingredient in milk to produce lactase-treated milk, which contains less lactose...

21 CFR 184.1388 - Lactase enzyme preparation from Kluyveromyces lactis.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-galactoside galactohydrase (CAS Reg. No. CBS 683), which converts lactose to glucose and galactose. It is... in § 170.3(o)(9) of this chapter to convert lactose to glucose and galactose. (2) The ingredient is... practice is to use this ingredient in milk to produce lactase-treated milk, which contains less lactose...

Adjuvant Effects Elicited by Novel Oligosaccharide Variants of Detoxified Meningococcal Lipopolysaccharides on Neisseria meningitidis Recombinant PorA Protein: A Comparison in Mice

PubMed Central

Mehta, Ojas H.; Norheim, Gunnstein; Hoe, J . Claire; Rollier, Christine S.; Nagaputra, Jerry C.; Makepeace, Katherine; Saleem, Muhammad; Chan, Hannah; Ferguson, David J. P.; Jones, Claire; Sadarangani, Manish; Hood, Derek W.; Feavers, Ian; Derrick, Jeremy P.; Pollard, Andrew J.; Moxon, E . Richard

2014-01-01

Neisseria meningitidis lipopolysaccharide (LPS) has adjuvant properties that can be exploited to assist vaccine immunogenicity. The modified penta-acylated LPS retains the adjuvant properties of hexa-acylated LPS but has a reduced toxicity profile. In this study we investigated whether two modified glycoform structures (LgtE and IcsB) of detoxified penta-acylated LPS exhibited differential adjuvant properties when formulated as native outer membrane vesicles (nOMVs) as compared to the previously described LgtB variant. Detoxified penta-acylated LPS was obtained by disruption of the lpxL1 gene (LpxL1 LPS), and three different glycoforms were obtained by disruption of the lgtB, lgtE or icsB genes respectively. Mice (mus musculus) were immunized with a recombinant PorA P1.7-2,4 (rPorA) protein co-administered with different nOMVs (containing a different PorA serosubtype P1.7,16), each of which expressed one of the three penta-acylated LPS glycoforms. All nOMVs induced IgG responses against the rPorA, but the nOMVs containing the penta-acylated LgtB-LpxL1 LPS glycoform induced significantly greater bactericidal activity compared to the other nOMVs or when the adjuvant was Alhydrogel. Compared to LgtE or IcsB LPS glycoforms, these data support the use of nOMVs containing detoxified, modified LgtB-LpxL1 LPS as a potential adjuvant for future meningococcal protein vaccines. PMID:25545241

Global Microlending in Education Reform: Enseñá Por Argentina and the Neoliberalization of the Grassroots

ERIC Educational Resources Information Center

Friedrich, Daniel S.

2010-01-01

This article examines the workings and underlying assumptions behind Enseñá por Argentina (Teach for Argentina), one specific program that takes part in the larger and expanding network of Teach for All, by thinking about the ways in which a global push for redefining teaching and teacher education encounters local characteristics and histories,…

Concepciones y concepciones alternativas de estudiantes universitarios/as de biologia y futuros maestros/as de Ciencia de escuela secundaria sobre la teoria de evolucion biologica por seleccion natural

NASA Astrophysics Data System (ADS)

Morales Ramos, Egda M.

La teoria de evolucion biologica (TEB) por seleccion natural es uno de los conceptos unificadores mas importantes del curriculo de Biologia. En Puerto Rico se han hecho pocas investigaciones que abunden sobre las concepciones y concepciones alternativas (CA) que tienen los estudiantes universitarios/as de Biologia y los maestros/as de Ciencia del nivel secundario sobre esta teoria. La politica publica educativa actual establece mediante documentos normativos como los Estandares de contenido y Expectativas de grado del Programa de Ciencias [Puerto Rico Core Standards] la ensenanza de esta teoria. Sin embargo, no se encontraron preguntas sobre la seleccion natural en los ejercicios de practica provistos por el Departamento de Educacion para las pruebas estandarizadas lo cual puede influir para que no se ensene adecuadamente. Las preguntas de investigacion fueron 1. ¿Cuales son las concepciones y concepciones alternativas de estudiantes universitarios/as y de los futuros maestros y maestras de Ciencia sobre la TEB? 2. ¿Cuales conceptos que seleccionan los estudiantes universitarios/as y los futuros maestros y maestras de Ciencia sobre la TEB coinciden con lo aceptado como valido por la comunidad cientifica? y 3. ¿Como comparan las respuestas de la prueba original. v. Entendiendo el cambio biologico que mide concepciones y CA sobre la TEB por seleccion natural, con las de la traducida al idioma espanol? Se utilizo el metodo cuantitativo con un diseno de investigacion transversal por encuesta. La tecnica principal para recopilar los datos fue una prueba con doce items, que formo parte de un instrumento para el cual se recopilaron diversas fuentes de evidencia acerca de su validez. Las muestras estuvieron formadas por 69 estudiantes de Ciencias Naturales y por 16 estudiantes futuros maestros y maestras del nivel secundario de la UPR-RP. Se utilizaron estadisticas descriptivas, analisis de Ji cuadrado y se calcularon los coeficientes alfa de Cronbach y de Spearman

Microbiological and biochemical aspects of Camembert-type cheeses depend on atmospheric composition in the ripening chamber.

PubMed

Leclercq-Perlat, M-N; Picque, D; Riahi, H; Corrieu, G

2006-08-01

Camembert-type cheeses were prepared from pasteurized milk seeded with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti, and Brevibacterium aurantiacum. Microorganism growth and biochemical dynamics were studied in relation to ripening chamber CO(2) atmospheric composition using 31 descriptors based on kinetic data. The chamber ripening was carried out under 5 different controlled atmospheres: continuously renewed atmosphere, periodically renewed atmosphere, no renewed atmosphere, and 2 for which CO(2) was either 2% or 6%. All microorganism dynamics depended on CO(2) level. Kluyveromyces lactis was not sensitive to CO(2) during its growth phases, but its death did depend on it. An increase of CO(2) led to a significant improvement in G. candidum. Penicillium camemberti mycelium development was enhanced by 2% CO(2). The equilibrium between P. camemberti and G. candidum populations was disrupted in favor of the yeast when CO(2) was higher than 4%. Growth of B. aurantiacum depended more on O(2) than on CO(2). Two ripening progressions were observed in relation to the presence of CO(2) at the beginning of ripening: in the presence of CO(2), the ripening was fast-slow, and in the absence of CO(2), it was slow-fast. The underrind was too runny if CO(2) was equal to or higher than 6%. The nitrogen substrate progressions were slightly related to ripening chamber CO(2) and O(2) levels. During chamber ripening, the best atmospheric condition to produce an optimum between microorganism growth, biochemical dynamics, and cheese appearance was a constant CO(2) level close to 2%.

Beta-galactosidase catalyzed selective galactosylation of aromatic compounds.

PubMed

Bridiau, Nicolas; Taboubi, Selma; Marzouki, Nejib; Legoy, Marie Dominique; Maugard, Thierry

2006-01-01

A new approach to galacto-oligosaccharides and galacto-conjugates synthesis performed by the beta-galactosidase from Kluyveromyces lactis is reported. The enzymatic galactosylation of eight kinds of adsorbed aromatic primary alcohols, in particular the two drugs guaifenesin and chlorphenesin, gave the corresponding beta-D-galacto-pyranosides in yields ranging between approximately 10% and 96%. For the first time, we have showed that the adsorption of acceptor substrates onto solid supports such as silica gel influences the yield and the selectivity of galacto-conjugates synthesis. In particular, we observed that adsorption of acceptor favored the synthesis of digalactosylated compounds.

Pincharse sin infectarse: estrategias para prevenir la infección por el VIH y el VHC entre usuarios de drogas inyectables

PubMed Central

MATEU-GELABERT, P.; FRIEDMAN, S.; SANDOVAL, M.

2011-01-01

Resumen Objetivo Desde principios de los noventa, en la ciudad de Nueva York se han implementado con éxito programas para reducir la incidencia del virus de la inmunodeficiencia humana (VIH) y, en menor medida, del virus de la hepatitis C (VHC). A pesar de ello, aproximadamente el 70% de los usuario de drogas inyectables (UDI) están infectados por el VHC. Queremos investigar cómo el 30% restante se las ha arreglado para no infectarse. El Staying safe (nombre original del estudio) explora los comportamientos y mecanismos que ayudan a evitar la infección por el VHC y el VIH a largo plazo. Material y métodos Hemos utilizado el concepto de «desviación positiva» aplicado en otros campos de salud pública. Estudiamos las estrategias, prácticas y tácticas de prevención de aquellos UDI que, viviendo en contextos de alta prevalencia, se mantienen sin infectar por VIH y el VHC, a pesar de haberse inyectado heroína durante años. Los resultados preliminares presentados en este artículo incluyen el análisis de las entrevistas realizadas a 25 UDI (17 doble negativos, 3 doble positivos y 5 con infección por el VHC y sin infección por el VIH). Se usaron entrevistas semiestructuradas que exploraban con detalle la historia de vida de los sujetos, incluyendo su consumo de drogas, redes sociales, contacto con instituciones, relaciones sexuales y estrategias de protección y vigilancia. Resultados La intencionalidad es importante para no infectarse, especialmente durante períodos de involución (períodos donde hay un deterioro económico y/o social que llevan al que se inyecta a situaciones de mayor riesgo). Presentamos tres dimensiones independientes de intencionalidad que conllevan comportamientos que pueden ayudar a prevenir la infección: a) evitar «el mono» (síntomas de abstención) asegurando el acceso a la droga; b) «llevarlo bien» para no convertirse en un junkie y así evitar la «muerte social» y la falta de acceso a los recursos, y c) seguir sin

Acceptance test report for portable exhauster POR-007/Skid E

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kriskovich, J.R.

1998-07-24

This document describes Acceptance Testing performed on Portable Exhauster POR-007/Skid E. It includes measurements of bearing vibration levels, pressure decay testing, programmable logic controller interlocks, high vacuum, flow and pressure control functional testing. The purpose of Acceptance testing documented by this report was to demonstrate compliance of the exhausters with the performance criteria established within HNF-0490, Rev. 1 following a repair and upgrade effort at Hanford. In addition, data obtained during this testing is required for the resolution of outstanding Non-conformance Reports (NCR), and finally, to demonstrate the functionality of the associated software for the pressure control and high vacuummore » exhauster operating modes provided for by W-320. Additional testing not required by the ATP was also performed to assist in the disposition and close out of receiving inspection report and for application design information (system curve). Results of this testing are also captured within this document.« less

Study of the interaction mechanisms between absorbed NO{sub 2} and por-Si/SnO{sub x} nanocomposite layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotov, V. V.; Kan, V. E., E-mail: kan@obisp.oscsbras.ru; Makushenko, R. K.

2013-10-15

The interaction mechanisms between NO{sub 2} molecules and the surface of por-Si/SnO{sub x} nanocomposites obtained by magnetron deposition and chemical vapor deposition (CVD) are studied by infrared absorption spectroscopy and electron paramagnetic resonance methods. The observed increase in the free carrier concentration in the por-Si/SnO{sub x} nanocomposite layers is explained by a change in the charge state of P{sub b} centers due to the formation of neutral 'surface defect-adsorbed NO{sub 2} molecule' complexes with free carrier generation in the crystallite bulk. In the nanocomposite layers grown by the CVD method, the increase in the free hole concentration during NO{sub 2}more » adsorption is much less pronounced in comparison with the composite grown by magnetron deposition, which is caused by the competing interaction channel of NO{sub 2} molecules with electrically neutral P{sub b} centers.« less

Acceptance test report for portable exhauster POR-008/Skid F

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kriskovich, J.R.

1998-07-24

Portable Exhauster POR-008 was procured via HNF-0490, Specification for a Portable Exhausted System for Waste Tank Ventilation. Prior to taking ownership, acceptance testing was performed at the vendors. However at the conclusion of testing a number of issues remained that required resolution before the exhausters could be used by Project W-320. The purpose of acceptance testing documented by this report was to demonstrate compliance of the exhausters with the performance criteria established within HNF-O49O, Rev. 1 following a repair and upgrade effort at Hanford. In addition, data obtained during this testing is required for the resolution of outstanding Non-conformance Reportsmore » (NCR), and finally, to demonstrate the functionality of the associated software for the pressure control and high vacuum exhauster operating modes provided for by W-320. Additional testing not required by the ATP was also performed to assist in the disposition and close out of receiving inspection report and for application design information (system curve). Results of this testing are also captured within this document.« less

Análise dos Conceitos Astronômicos Apresentados por Professores de Algumas Escolas Estaduais Brasileiras

NASA Astrophysics Data System (ADS)

Voelzke, Marcos Rincon; Gonzaga, Edson Pereira

2011-12-01

A razão para o desenvolvimento deste trabalho baseia-se no fato de que muitos professores da Educação Básica (EB) não lidam com conceitos relacionados à astronomia, e quando o fazem eles simplesmente seguem livros didáticos que podem conter erros conceituais. Como é de conhecimento geral a astronomia é um dos conteúdos a serem ensinados na EB fazendo parte dos Parâmetros Curriculares Nacionais e das Propostas Curriculares do Estado de São Paulo, mas é um fato, que vários pesquisadores apontam, a existência de muitos problemas no ensino da astronomia. Com o propósito de minimizar algumas dessas deficiências foi realizado um trabalho de pesquisa com a utilização de questionários pré e pós pesquisa, para tanto foi desenvolvido um Curso de Extensão Universitária para professores da Diretoria de Ensino Regional (DE) que abrange Mauá, Ribeirão Pires e Rio Grande da Serra (no Estado de São Paulo) com os seguintes objetivos: levantar concepções alternativas; subsidiar os professores por meio de palestras, debates e workshops, e verificar o sucesso da aprendizagem após o curso, adotando-se como referência, para a análise dos resultados, os dicionários de Língua Portuguesa (FERREIRA, 2004) e Enciclopédico de Astronomia e Astronáutica (MOURĀO, 1995). Portanto, dezesseis questões foram aplicadas antes e após o curso, assim pode-se verificar após a pesquisa que 100,0% dos professores sabiam os nomes das fases da Lua, 97,0% entenderam que o Sistema Solar é composto por oito planetas, 78,1% foram capazes de explicar como ocorre um eclipse lunar, um eclipse solar e um solstício, 72,7% sabiam como explicar a ocorrência das estações do ano; 64,5% explicaram corretamente a ocorrência do equinócio, 89,7% foram capazes de definir adequadamente o termo cometa; 63,6% definiram asteróide, 54,5% meteoro, 58,1% galáxia, e 42,4% planeta. Os resultados obtidos indicam uma aprendizagem significativa por parte dos participantes.

Microbial terroir and food innovation: The case of yeast biodiversity in wine.

PubMed

Capozzi, Vittorio; Garofalo, Carmela; Chiriatti, Maria Assunta; Grieco, Francesco; Spano, Giuseppe

2015-12-01

Saccharomyces and non-Saccharomyces represents a heterogeneous class in the grape/must/wine environments including several yeast genera (e.g., Saccharomyces, Hanseniaspora, Pichia, Candida, Metschnikowia, Kluyveromyces, Zygosaccharomyces, Torulaspora, Dekkera and Schizosaccharomyces) and species. Since, each species may differently contribute to the improvement/depreciation of wine qualities, it appears clear the reason why species belong to non-Saccharomyces are also considered a biotechnological resource in wine fermentation. Here, we briefly review the oenological significance of this specific part of microbiota associated with grapes/musts/wine. Moreover, the diversity of cultivable non-Saccharomyces genera and their contribute to typical wines fermentations will be discussed. Copyright © 2015 Elsevier GmbH. All rights reserved.

Optimization of the simultaneous saccharification and fermentation process using thermotolerant yeasts.

PubMed

Ballesteros, I; Oliva, J M; Ballesteros, M; Carrasco, J

1993-01-01

Different treatments to improve the thermotolerance of fermenting yeasts for simultaneous ethanol saccharification and fermentation process of cellulosic materials have been examined. Yeasts of the genera Saccharomyces and Kluyveromyces were tested for growth and fermentation at progressively higher temperatures in the range of 42-47 degrees C. The best results were obtained with K. marxianus LG, which was then submitted to different treatments in order to achieve thermotolerant clones. A total of 35 new clones were obtained that dramatically improved the SSF of 10% Solka-floc substrate at 45 degrees C when compared to the original strain, some with ethanol concentrations as high as 33 g/L.

Using the PORS Problems to Examine Evolutionary Optimization of Multiscale Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinhart, Zachary; Molian, Vaelan; Bryden, Kenneth

2013-01-01

Nearly all systems of practical interest are composed of parts assembled across multiple scales. For example, an agrodynamic system is composed of flora and fauna on one scale; soil types, slope, and water runoff on another scale; and management practice and yield on another scale. Or consider an advanced coal-fired power plant: combustion and pollutant formation occurs on one scale, the plant components on another scale, and the overall performance of the power system is measured on another. In spite of this, there are few practical tools for the optimization of multiscale systems. This paper examines multiscale optimization of systemsmore » composed of discrete elements using the plus-one-recall-store (PORS) problem as a test case or study problem for multiscale systems. From this study, it is found that by recognizing the constraints and patterns present in discrete multiscale systems, the solution time can be significantly reduced and much more complex problems can be optimized.« less

Adult Student Retention and Achievement with Language-Based Modular Materials. POR FIN: Program Organizing Related Family Instruction in the Neighborhood.

ERIC Educational Resources Information Center

Bexar County School Board, San Antonio, TX.

The goal of the POR FIN research design was to develop a language-based curriculum emphasizing the audiolingual approach and integrating academic and social-functioning subject matter. The modular curriculum is designed so that each lesson is independent and complete in itself, and provides a high degree of motivation, retention, and achievement…

Characterisation by multilocus sequence and porA and flaA typing of Campylobacter jejuni isolated from samples of dog faeces collected in one city in New Zealand.

PubMed

Mohan, V; Stevenson, M A; Marshall, J C; French, N P

2017-07-01

To investigate the prevalence of Campylobacter spp. and C. jejuni in dog faecal material collected from dog walkways in the city of Palmerston North, New Zealand, and to characterise the C. jejuni isolates by multilocus sequence typing (MLST) and porA and flaA antigen gene typing. A total of 355 fresh samples of dogs faeces were collected from bins provided for the disposal of dog faeces in 10 walkways in Palmerston North, New Zealand, between August 2008-July 2009. Presumptive Campylobacter colonies, cultured on modified charcoal cefoperazone deoxycholate plates, were screened for genus Campylobacter and C. jejuni by PCR. The C. jejuni isolates were subsequently characterised by MLST and porA and flaA typing, and C. jejuni sequence types (ST) were assigned. Of the 355 samples collected, 72 (20 (95% CI=16-25)%) were positive for Campylobacter spp. and 22 (6 (95% CI=4-9)%) were positive for C. jejuni. Of the 22 C. jejuni isolates, 19 were fully typed by MLST. Ten isolates were assigned to the clonal complex ST-45 and three to ST-52. The allelic combinations of ST-45/flaA 21/porA 44 (n=3), ST-45/flaA 22/porA 53 (n=3) and ST-52/ flaA 57/porA 905 (n=3) were most frequent. The successful isolation of C. jejuni from canine faecal samples collected from faecal bins provides evidence that Campylobacter spp. may survive outside the host for at least several hours despite requiring fastidious growth conditions in culture. The results show that dogs carry C. jejuni genotypes (ST-45, ST-50, ST-52 and ST-696) that have been reported in human clinical cases. Although these results do not provide any evidence either for the direction of infection or for dogs being a potential risk factor for human campylobacteriosis, dog owners are advised to practice good hygiene with respect to their pets to reduce potential exposure to infection.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

PubMed

Smith, I M; Baker, A; Arneborg, N; Jespersen, L

2015-11-01

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

Cloning and sequence analysis of the invertase gene INV 1 from the yeast Pichia anomala.

PubMed

Pérez, J A; Rodríguez, J; Rodríguez, L; Ruiz, T

1996-02-01

A genomic library from the yeast Pichia anomala has been constructed and employed to clone the gene encoding the sucrose-hydrolysing enzyme invertase by complementation of a sucrose non-fermenting mutant of Saccharomyces cerevisiae. The cloned gene, INV1, was sequenced and found to encode a polypeptide of 550 amino acids which contained a 22 amino-acid signal sequence and ten potential glycosylation sites. The amino-acid sequence shows significant identity with other yeast invertases and also with Kluyveromyces marxianus inulinase, a yeast beta-fructofuranosidase which has a different substrate specificity. The nucleotide sequences of the 5' and 3' non-coding regions were found to contain several consensus motifs probably involved in the initiation and termination of gene transcription.

Controlled Microbial Cenoses in Closed Spaces

NASA Astrophysics Data System (ADS)

Somova, Lydia; Mikheeva, Galina

Controlled microbial cenoses have good prospects in closed spaces: for air treatment in LSS and cellars industrial premises; for sewage treatment in LSS; for increase of productivity and protect of plants from infections in LSS. Possible methods of formation of microbiocenoses are: selection, autoselection, artificial formation taking into account their biochemical properties and metabolic interactions. Experimental microbiocenoses, has been produced on the basis of natural association of microorganisms by long cultivation on specially developed medium. Dominating groups are bacteria of genera: Lactobacillus, Streptococcus, Leuconostoc, Bidobac-terium, Rhodopseudomonas and yeast of genera: Kluyveromyces, Saccharomyces and Torulop-sis. Microbiocenoses do not contain pathogenic and conditionally pathogenic microorganisms, they possess opposing and probiotic properties. Different examples of microbial cenoses actions are to be presented in the paper.

Biofuel production from Jerusalem artichoke tuber inulins: a review

DOE PAGES

Bhagia, Samarthya; Akinosho, Hannah; Ferreira, Jorge F. S.; ...

2017-06-01

Jerusalem artichoke (JA) has a high productivity of tubers that are rich in inulins, a fructan polymer. These inulins can be easily broken down into fructose and glucose for conversion into ethanol by fermentation. This paper discusses tuber and inulin yields, effect of cultivar and environment on tuber productivity, and approaches to fermentation for ethanol production. Consolidated bioprocessing with Kluyveromyces marxianus has been the most popular approach for fermentation into ethanol. Apart from ethanol, fructose can be dehydrated into into 5-hydrolxymethylfurfural followed by catalytic conversion into hydrocarbons. Finally, findings from several studies indicate that this plant from tubers alone canmore » produce ethanol at yields that rival corn and sugarcane ethanol. JA has tremendous potential for use as a bioenergy feedstock.« less

Biofuel production from Jerusalem artichoke tuber inulins: a review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhagia, Samarthya; Akinosho, Hannah; Ferreira, Jorge F. S.

Jerusalem artichoke (JA) has a high productivity of tubers that are rich in inulins, a fructan polymer. These inulins can be easily broken down into fructose and glucose for conversion into ethanol by fermentation. This paper discusses tuber and inulin yields, effect of cultivar and environment on tuber productivity, and approaches to fermentation for ethanol production. Consolidated bioprocessing with Kluyveromyces marxianus has been the most popular approach for fermentation into ethanol. Apart from ethanol, fructose can be dehydrated into into 5-hydrolxymethylfurfural followed by catalytic conversion into hydrocarbons. Finally, findings from several studies indicate that this plant from tubers alone canmore » produce ethanol at yields that rival corn and sugarcane ethanol. JA has tremendous potential for use as a bioenergy feedstock.« less

Cell lysis induced by membrane-damaging detergent saponins from Quillaja saponaria.

PubMed

Berlowska, Joanna; Dudkiewicz, Marta; Kregiel, Dorota; Czyzowska, Agata; Witonska, Izabela

2015-01-01

This paper presents the results of a study to determine the effect of Quillaja saponaria saponins on the lysis of industrial yeast strains. Cell lysis induced by saponin from Q. saponaria combined with the plasmolysing effect of 5% NaCl for Saccharomyces cerevisiae, Kluyveromyces marxianus yeasts biomass was conducted at 50 °C for 24-48 h. Membrane permeability and integrity of the yeast cells were monitored using fluorescent techniques and concentrations of proteins, free amino nitrogen (FAN) and free amino acids in resulting lysates were analyzed. Protein release was significantly higher in the case of yeast cell lysis promoted with 0.008% Q. saponaria and 5% NaCl in comparison to plasmolysis triggered by NaCl only. Copyright © 2015 Elsevier Inc. All rights reserved.

Selection of thermotolerant yeasts for simultaneous saccharification and fermentation (SSF) of cellulose to ethanol.

PubMed

Ballesteros, I; Ballesteros, M; Cabañas, A; Carrasco, J; Martín, C; Negro, M J; Saez, F; Saez, R

1991-01-01

A total of 27 yeast strains belonging to the groups Candida, Saccharomyces, and Kluyveromyces were screened for their ability to grow and ferment glucose at temperatures ranging 32-45 degrees C. K. marxianus and K. fragilis were found to be the best ethanol producing organisms at the higher temperature tested and, so, were selected for subsequent simultaneous saccharification and fermentation (SSF) studies. SSF experiments were performed at 42 and 45 degrees C, utilizing Solkafloc (10%) as cellulose substrate and a cellulase loading of 15 FPU/g substrate. Best results were achieved at 42 degrees C with K. marxianus L. G. and K. fragilis L. G., both of which produced close to 38 g/L ethanol and 0.5 ethanol yield, in 78 h.

Bioreduction of α,β-unsaturated ketones and aldehydes by non-conventional yeast (NCY) whole-cells.

PubMed

Goretti, Marta; Ponzoni, Chiara; Caselli, Elisa; Marchegiani, Elisabetta; Cramarossa, Maria Rita; Turchetti, Benedetta; Forti, Luca; Buzzini, Pietro

2011-03-01

The bioreduction of α,β-unsaturated ketones (ketoisophorone, 2-methyl- and 3-methyl-cyclopentenone) and aldehydes [(S)-(-)-perillaldehyde and α-methyl-cinnamaldehyde] by 23 "non-conventional" yeasts (NCYs) belonging to 21 species of the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma, and Wickerhamomyces was reported. The results highlight the potential of NCYs as whole-cell biocatalysts for selective biotransformation of electron-poor alkenes. A few NCYs exhibited extremely high (>90%) or even total ketoisophorone and 2-methyl-cyclopentenone bioconversion yields via asymmetric reduction of the conjugated CC bond catalyzed by enoate reductases. Catalytic efficiency declined after switching from ketones to aldehydes. High chemoselectivity due to low competing carbonyl reductases was also sometimes observed. Copyright © 2010 Elsevier Ltd. All rights reserved.

El proceso hacia la integracion de la equidad por genero al curriculo.(The Process of the Integration of Gender Equity in the Curriculum.)

ERIC Educational Resources Information Center

Rivera-Bermudez, Carmen D.

"El Proyecto Colaborativo de Equidad por Genero en la Educacion," or the Collaborative Project for Gender Equity in Education, was undertaken in Puerto Rico between 1990 and 1992 to study how to facilitate the integration of gender equity themes in the curriculum through the direct action of participating teachers. A study examined the…

Protection by meningococcal outer membrane protein PorA-specific antibodies and a serogroup B capsular polysaccharide-specific antibody in complement-sufficient and C6-deficient infant rats.

PubMed

Toropainen, Maija; Saarinen, Leena; Vidarsson, Gestur; Käyhty, Helena

2006-05-01

The relative contributions of antibody-induced complement-mediated bacterial lysis and antibody/complement-mediated phagocytosis to host immunity against meningococcal infections are currently unclear. Further, the in vivo effector functions of antibodies may vary depending on their specificity and Fc heavy-chain isotype. In this study, a mouse immunoglobulin G2a (mIgG2a) monoclonal antibody (MN12H2) to meningococcal outer membrane protein PorA (P1.16), its human IgG subclass derivatives (hIgG1 to hIgG4), and an mIgG2a monoclonal antibody (Nmb735) to serogroup B capsular polysaccharide (B-PS) were evaluated for passive protection against meningococcal serogroup B strain 44/76-SL (B:15:P1.7,16) in an infant rat infection model. Complement component C6-deficient (PVG/c-) rats were used to assess the importance of complement-mediated bacterial lysis for protection. The PorA-specific parental mIgG2a and the hIgG1 to hIgG3 derivatives all induced efficient bactericidal activity in vitro in the presence of human or infant rat complement and augmented bacterial clearance in complement-sufficient HsdBrlHan:WIST rats, while the hIgG4 was unable to do so. In C6-deficient PVG/c- rats, lacking complement-mediated bacterial lysis, the augmentation of bacterial clearance by PorA-specific mIgG2a and hIgG1 antibodies was impaired compared to that in the syngeneic complement-sufficient PVG/c+ rat strain. This was in contrast to the case for B-PS-specific mIgG2a, which conferred similar protective activity in both rat strains. These data suggest that while anti-B-PS antibody can provide protection in the infant rats without membrane attack complex formation, the protection afforded by anti-PorA antibody is more dependent on the activation of the whole complement pathway and subsequent bacterial lysis.

Fine Structure of Tibetan Kefir Grains and Their Yeast Distribution, Diversity, and Shift

PubMed Central

Lu, Man; Wang, Xingxing; Sun, Guowei; Qin, Bing; Xiao, Jinzhou; Yan, Shuling; Pan, Yingjie; Wang, Yongjie

2014-01-01

Tibetan kefir grains (TKGs), a kind of natural starter for fermented milk in Tibet, China, host various microorganisms of lactic acid bacteria, yeasts, and occasionally acetic acid bacteria in a polysaccharide/protein matrix. In the present study, the fine structure of TKGs was studied to shed light on this unusual symbiosis with stereomicroscopy and thin sections. The results reveal that TKGs consist of numerous small grain units, which are characterized by a hollow globular structure with a diameter between 2.0 and 9.0 mm and a wall thickness of approximately 200 µm. A polyhedron-like net structure, formed mainly by the bacteria, was observed in the wall of the grain units, which has not been reported previously to our knowledge. Towards the inside of the grain unit, the polyhedron-like net structures became gradually larger in diameter and fewer in number. Such fine structures may play a crucial role in the stability of the grains. Subsequently, the distribution, diversity, and shift of yeasts in TKGs were investigated based on thin section, scanning electron microscopy, cloning and sequencing of D1/D2 of the 26S rRNA gene, real-time quantitative PCR, and in situ hybridization with specific fluorescence-labeled oligonucleotide probes. These show that (i) yeasts appear to localize on the outer surface of the grains and grow normally together to form colonies embedded in the bacterial community; (ii) the diversity of yeasts is relatively low on genus level with three dominant species – Saccharomyces cerevisiae, Kluyveromyces marxianus, and Yarrowia lipolytica; (iii) S. cerevisiae is the stable predominant yeast species, while the composition of Kluyveromyces and Yarrowia are subject to change over time. Our results indicate that TKGs are relatively stable in structure, and culture conditions to some extent shape the microbial community and interaction in kefir grains. These findings pave the way for further study of the specific symbiotic associations between S

Novel high-performance metagenome β-galactosidases for lactose hydrolysis in the dairy industry.

PubMed

Erich, Sarah; Kuschel, Beatrice; Schwarz, Thilo; Ewert, Jacob; Böhmer, Nico; Niehaus, Frank; Eck, Jürgen; Lutz-Wahl, Sabine; Stressler, Timo; Fischer, Lutz

2015-09-20

The industrially utilised β-galactosidases from Kluyveromyces spp. and Aspergillus spp. feature undesirable kinetic properties in praxis, such as an unsatisfactory lactose affinity (KM) and product inhibition (KI) by galactose. In this study, a metagenome library of about 1.3 million clones was investigated with a three-step activity-based screening strategy in order to find new β-galactosidases with more favourable kinetic properties. Six novel metagenome β-galactosidases (M1-M6) were found with an improved lactose hydrolysis performance in original milk when directly compared to the commercial β-galactosidase from Kluyveromyces lactis (GODO-YNL2). The best metagenome candidate, called "M1", was recombinantly produced in Escherichia coli BL21(DE3) in a bioreactor (volume 35 L), resulting in a total β-galactosidase M1 activity of about 1100 μkatoNPGal,37 °C L(-1). Since milk is a sensitive and complex medium, it has to be processed at 5-10 °C in the dairy industry. Therefore, the β-galactosidase M1 was tested at 8 °C in milk and possessed a good stability (t1/2=21.8 d), a desirably low apparent KM,lactose,8 °C value of 3.8±0.7 mM and a high apparent KI,galactose,8 °C value of 196.6±55.5 mM. A lactose hydrolysis process (milk, 40 nkatlactose mLmilk,8 °C(-1)) was conducted at a scale of 0.5L to compare the performance of M1 with the commercial β-galactosidase from K. lactis (GODO-YNL2). Lactose was completely (>99.99%) hydrolysed by M1 and to 99.6% (w/v) by K. lactis β-galactosidase after 25 h process time. Thus, M1 was able to achieve the limit of <100 mg lactose per litre milk, which is recommended for dairy products labelled as "lactose-free". Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Seguridad del paciente en Radioterapia Intraoperatoria: Impacto de los elementos controlados por el Radiofisico

NASA Astrophysics Data System (ADS)

Tarjuelo, Juan Lopez

Introduccion: En la administracion de la radioterapia intervienen profesionales y equipos de tratamiento, por lo que existe el riesgo de error y se precisa que dicho equipamiento funcione conforme a lo esperado. A los radiofisicos les corresponde participar en las actividades de garantia o aseguramiento de la calidad, incluyendo el control de calidad de los equipos, y en la evaluacion de los riesgos asociados. La radioterapia intraoperatoria (RIO) es una tecnica radioterapica de intensificacion de dosis, altamente selectiva, dirigida a volumenes anatomicos restringidos durante el tratamiento quirurgico oncologico, basada en la administracion de una dosis absorbida alta por medio de un haz de electrones tras el examen visual directo del lecho tumoral. Como incorporar los ultimos avances en el refuerzo de la seguridad en radioterapia es una tarea ambiciosa y compleja, resulta mas concreta y de inmediata aplicacion su introduccion en la RIO. El objetivo es analizar los elementos que reducen los riesgos y aumentan la seguridad en la RIO y su dosimetria, y valorar la funcion del radiofisico en esta labor. Material y metodos: Se emplearon el planificador Radiance de GMV y el acelerador lineal de los tratamientos de RIO Elekta Precise, controlado con el verificador diario de haces Daily QA Check 1090 y medido con las camaras de ionizacion PPC 40, FC65-G y FC65-P de PTW-Freiburg, a su vez verificadas con fuentes radiactivas adecuadas de estroncio-90 modelos CDP y CDC de IBA Dosimetry. Se realizo un analisis de modos de fallo y efectos (failure mode and effect analysis, FMEA) con el fin de identificar los elementos que forman la RIO y aplicar las herramientas necesarias para la minimizacion de los riesgos y la mejora de la seguridad en la tecnica. Se estudiaron las verificaciones diarias de dicho acelerador Precise con el control estadistico de procesos (statistical process control, SPC) y se simularon intervenciones para devolverlo al estado llamado en control. El SPC

Evolution of the carboxylate Jen transporters in fungi.

PubMed

Lodi, Tiziana; Diffels, Julie; Goffeau, André; Baret, Philippe V

2007-08-01

Synteny analysis is combined with sequence similarity and motif identification to trace the evolution of the putative monocarboxylate (lactate/pyruvate) transporters Jen1p and the dicarboxylate (succinate/fumarate/malate) transporters Jen2p in Hemiascomycetes yeasts and Euascomycetes fungi. It is concluded that a precursor form of Jen1p, named here preJen1p, arose by the duplication of an ancestral Jen2p, during the speciation of Yarrowia lipolytica, which was transferred into a new syntenic context. The Jen1p transporters differentiated from preJen1p in Kluyveromyces lactis, before the Whole Genome Duplication (WGD), and are conserved as a single copy in the Saccharomyces species. In contrast, the ancestral Jen2p was definitively lost just prior to the WGD and is absent in Saccharomyces.

Fabrication of por-Si/SnO{sub x} nanocomposite layers for gas microsensors and nanosensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotov, V. V., E-mail: bolotov@obisp.oscsbras.ru; Korusenko, P. M.; Nesov, S. N.

2011-05-15

Two-phase nanocomposite layers based on porous silicon and nonstoichiometric tin oxide were fabricated by various methods. The structure, as well as elemental and phase composition, of the obtained nanocomposites were studied using transmission and scanning electron microscopy, Raman spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The results obtained confirm the formation of nanocomposite layers with a thickness as large as 2 {mu}m thick and SnO{sub x} stoichiometry coefficients x = 1.0-2.0. Significant tin diffusion into the porous silicon matrix with D{sub eff} Almost-Equal-To 10{sup -14} cm{sup 2} s{sup -1} was observed upon annealing at 770 K. Test sensor structuresmore » based on por-Si/SnO{sub x} nanocomposite layers grown by magnetron deposition showed fairly high stability of properties and sensitivity to NO{sub 2}.« less

Being a mother and a por día domestic worker. Companionship and deprivation.

PubMed

Bernal, P; Meleis, A I

1995-08-01

This article presents qualitative findings concerning women's maternal roles, based on interviews conducted in a study on role integration and health, in a Colombian sample of 60 women who are "por día" domestic workers. The results describe the women's worldview as they discuss the stresses and the satisfactions of their mothering roles. The results also include the coping strategies used to deal with the stresses inherent in the maternal role. Women describe how the companionship of their children, watching their children grow, and the nurturing they give their children provides them with pride and deep satisfaction. These satisfying aspects of their role are burdened by the stress related to worry about children's bad behavior, their illness, and a pervasive generalized sense of constant worry. Being single parents adds more stress to these women's lives. Participants coped emotionally through distraction and through talking with friends. Other coping strategies included calming self, problem solving, talking with children, and substance use. The authors conclude with a discussion of the relationship between poverty and work situation as contexts for understanding maternal roles.

Dietary influence of kefir on microbial activities in the mouse bowel.

PubMed

Marquina, Domingo; Santos, A; Corpas, I; Muñoz, J; Zazo, J; Peinado, J M

2002-01-01

In this work the microflora present in kefir, a fermented milk product, was studied together with the effect of kefir administration on different groups of indigenous bacteria of mouse bowel. Kefir microflora was composed of lactic acid bacteria, acetic acid bacteria and yeasts. Yeast population was composed of Saccharomyces cerevisiae, S. unisporus, Candida kefir, Kluyveromyces marxianus and K. lactis. The streptococci levels in kefir treated mice increased by 10-fold and the levels of sulfite-reducing clostridia decreased by 100-fold. The number of lactic acid bacteria increased significantly. The administration of kefir significantly increased the lactic acid bacteria counts in the mucosa of the bowel. Ingestion of kefir specifically lowered microbial populations of Enterobacteriaceae and clostridia. This is the first long-term study about the effects of the kefir administration on the intestinal microflora of mice.

Glucose-free fructose production from Jerusalem artichoke using a recombinant inulinase-secreting Saccharomyces cerevisiae strain.

PubMed

Yu, Jing; Jiang, Jiaxi; Ji, Wangming; Li, Yuyang; Liu, Jianping

2011-01-01

Using inulin (polyfructose) obtained from Jerusalen artichokes, we have produced fructose free of residual glucose using a recombinant inulinase-secreting strain of Saccharomyces cerevisiae in a one-step fermentation of Jerusalem artichoke tubers. For producing fructose from inulin, a recombinant inulinase-producing Saccharomyce cerevisiae strain was constructed with a deficiency in fructose uptake by disruption of two hexokinase genes hxk1 and hxk2. The inulinase gene introduced into S. cerevisiae was cloned from Kluyveromyces cicerisporus. Extracellular inulinase activity of the recombinant hxk-mutated S. cerevisiae strain reached 31 U ml(-1) after 96 h growth. When grown in a medium containing Jerusalem artichoke tubers as the sole component without any additives, the recombinant yeast accumulated fructose up to 9.2% (w/v) in the fermentation broth with only 0.1% (w/v) glucose left after 24 h.

Extraction of genomic DNA from yeasts for PCR-based applications.

PubMed

Lõoke, Marko; Kristjuhan, Kersti; Kristjuhan, Arnold

2011-05-01

We have developed a quick and low-cost genomic DNA extraction protocol from yeast cells for PCR-based applications. This method does not require any enzymes, hazardous chemicals, or extreme temperatures, and is especially powerful for simultaneous analysis of a large number of samples. DNA can be efficiently extracted from different yeast species (Kluyveromyces lactis, Hansenula polymorpha, Schizosaccharomyces pombe, Candida albicans, Pichia pastoris, and Saccharomyces cerevisiae). The protocol involves lysis of yeast colonies or cells from liquid culture in a lithium acetate (LiOAc)-SDS solution and subsequent precipitation of DNA with ethanol. Approximately 100 nanograms of total genomic DNA can be extracted from 1 × 10(7) cells. DNA extracted by this method is suitable for a variety of PCR-based applications (including colony PCR, real-time qPCR, and DNA sequencing) for amplification of DNA fragments of ≤ 3500 bp.

Overexpression of pyruvate decarboxylase in the yeast Hansenula polymorpha results in increased ethanol yield in high-temperature fermentation of xylose.

PubMed

Ishchuk, Olena P; Voronovsky, Andriy Y; Stasyk, Oleh V; Gayda, Galina Z; Gonchar, Mykhailo V; Abbas, Charles A; Sibirny, Andriy A

2008-11-01

Improvement of xylose fermentation is of great importance to the fuel ethanol industry. The nonconventional thermotolerant yeast Hansenula polymorpha naturally ferments xylose to ethanol at high temperatures (48-50 degrees C). Introduction of a mutation that impairs ethanol reutilization in H. polymorpha led to an increase in ethanol yield from xylose. The native and heterologous (Kluyveromyces lactis) PDC1 genes coding for pyruvate decarboxylase were expressed at high levels in H. polymorpha under the control of the strong constitutive promoter of the glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH). This resulted in increased pyruvate decarboxylase activity and improved ethanol production from xylose. The introduction of multiple copies of the H. polymorpha PDC1 gene driven by the strong constitutive promoter led to a 20-fold increase in pyruvate decarboxylase activity and up to a threefold elevation of ethanol production.

Aquisição fonológica do português brasileiro por crianças ouvintes bilíngues bimodais e surdas usuárias de implante coclear

PubMed Central

Cruz, Carina Rebello; Finger, Ingrid

2014-01-01

Resumo O presente estudo investiga a aquisição fonológica do Português Brasileiro (PB) por 24 crianças ouvintes bilíngues bimodais, com acesso irrestrito à Língua Brasileira de Sinais (Libras), e por 6 crianças surdas que utilizam implante coclear (IC), com acesso restrito ou irrestrito à Libras. Para a avaliação do sistema fonológico das crianças em PB, foi utilizada a Parte A, Prova de Nomeação, do ABFW – Teste de Linguagem Infantil (ANDRADE et al. 2004). Os resultados revelaram que as crianças ouvintes bilíngues bimodais e a criança surda usuária de IC com acesso irrestrito à Libras apresentaram processo de aquisição fonológica esperada (normal) para a sua faixa etária. Considera-se que a aquisição precoce e o acesso irrestrito à Libras podem ter sido determinantes para o desempenho dessas crianças no teste oral utilizado. PMID:25506105

Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domingues, L.; Dantas, M.M.; Lima, N.

1999-09-20

Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cetevisiae, expressing the LAC4 (coding the {beta}-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L{sup {minus}1} h{sup {minus}1} (corresponding to a feed lactose concentration of 50 g L{sup {minus}1} and a dilution ratemore » of 0.55 h{sup {minus}1}) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months.« less

Simultaneous hydrolysis and co-fermentation of whey lactose with wheat for ethanol production.

PubMed

Jin, Yiqiong; Parashar, Archana; Mason, Beth; Bressler, David C

2016-12-01

Whey permeate was used as a co-substrate to replace part of the wheat for ethanol production by Saccharomyces cerevisiae. The simultaneous saccharification and fermentation was achieved with β-galactosidase added at the onset of the fermentation to promote whey lactose hydrolysis. Aspergillus oryzae and Kluyveromyces lactis β-galactosidases were two enzymes selected and used in the co-fermentation of wheat and whey permeate for the comparison of their effectiveness on lactose hydrolysis. The possibility of co-fermentations in both STARGEN and jet cooking systems was investigated in 5L bioreactors. Ethanol yields from the co-fermentations of wheat and whey permeate were evaluated. It was found that A. oryzae β-galactosidase was more efficient for lactose hydrolysis during the co-fermentation and that whey permeate supplementation can contribute to ethanol yield in co-fermentations with wheat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transgalactosylation and hydrolytic activities of commercial preparations of β-galactosidase for the synthesis of prebiotic carbohydrates.

PubMed

Guerrero, Cecilia; Vera, Carlos; Conejeros, Raúl; Illanes, Andrés

2015-03-01

β-Galactosidases exhibit both hydrolytic and transgalactosylation activities; the former has been used traditionally for the production of delactosed milk and dairies, while the latter is being increasingly used for the synthesis of lactose-derived oligosaccharides: balance between both activities was highly dependent on the enzyme origin: β-galactosidases from Aspegillus oryzae and Bacillus circulans exhibited high transgalactosylation activity, while those from one from Kluyveromyces exhibited high hydrolytic activity but quite low transgalactosylation activity. Also the affinity for the donors (lactose or lactulose) and the acceptors (lactose, lactulose or fructose) of transgalactosylated galactose was dependent on the enzyme origin, as reflected by the Michaelis constants obtained in the synthesis of galacto-oligosaccharides, fructosyl-galacto-oligosaccharides and lactulose. Finally, the balance between transgalactosylation and hydrolytic activities of β-galactosidases could be tuned by changing the concentration of galactose donor. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of the yeast and bacteria biomass on the microbiota in the rumen.

PubMed

Vamanu, E; Vamanu, A; Popa, O; Vassu, Tatiana; Ghindea, Raluca; Pelinescu, Diana; Nita, Sultana; Babeanu, Narcisa

2008-09-15

This study aims at obtaining a probiotic product based on viable biomass from 6 yeast strains and 2 strains of lactic bacteria used for nutrition of animals. The strains are subjected to some resistance tests, at temperature, pH, pepsin, pancreatin and biliary salts so as to make obvious their viability. Tests were done by comparison to the witness strain and respectively a protective solution based on mucin and casein. Based on the resulted viabilities 2 products are formulated. Their effect is tested by inoculating fresh rumen content and supervising the microbic balance for a period of 12 days. After the final tests, it resulted that the product Fpl (20% Saccharomyces cerevisiae 1-29, 10% Kluyveromyces marxianus R-CS, 20% Issatchenkia orientalis R-BC, 30% Lactobacillus paracasei CMGB16, 20% Enterococcus faecium GM8) was chosen because anaerobic strains were preponderant as a consequence of the tests performed with rumen.

Glycolysis Controls Plasma Membrane Glucose Sensors To Promote Glucose Signaling in Yeasts

PubMed Central

Cairey-Remonnay, Amélie; Deffaud, Julien; Wésolowski-Louvel, Micheline; Lemaire, Marc

2014-01-01

Sensing of extracellular glucose is necessary for cells to adapt to glucose variation in their environment. In the respiratory yeast Kluyveromyces lactis, extracellular glucose controls the expression of major glucose permease gene RAG1 through a cascade similar to the Saccharomyces cerevisiae Snf3/Rgt2/Rgt1 glucose signaling pathway. This regulation depends also on intracellular glucose metabolism since we previously showed that glucose induction of the RAG1 gene is abolished in glycolytic mutants. Here we show that glycolysis regulates RAG1 expression through the K. lactis Rgt1 (KlRgt1) glucose signaling pathway by targeting the localization and probably the stability of Rag4, the single Snf3/Rgt2-type glucose sensor of K. lactis. Additionally, the control exerted by glycolysis on glucose signaling seems to be conserved in S. cerevisiae. This retrocontrol might prevent yeasts from unnecessary glucose transport and intracellular glucose accumulation. PMID:25512610

Evolutionary relationships among pathogenic Candida species and relatives.

PubMed Central

Barns, S M; Lane, D J; Sogin, M L; Bibeau, C; Weisburg, W G

1991-01-01

Small subunit rRNA sequences have been determined for 10 of the most clinically important pathogenic species of the yeast genus Candida (including Torulopsis [Candida] glabrata and Yarrowia [Candida] lipolytica) and for Hansenula polymorpha. Phylogenetic analyses of these sequences and those of Saccharomyces cerevisiae, Kluyveromyces marxianus var. lactis, and Aspergillus fumigatus indicate that Candida albicans, C. tropicalis, C. parapsilosis, and C. viswanathii form a subgroup within the genus. The remaining significant pathogen, T. glabrata, falls into a second, distinct subgroup and is specifically related to S. cerevisiae and more distantly related to C. kefyr (psuedotropicalis) and K. marxianus var. lactis. The 18S rRNA sequence of Y. lipolytica has evolved rapidly in relation to the other Candida sequences examined and appears to be only distantly related to them. As anticipated, species of several other genera appear to bear specific relationships to members of the genus Candida. PMID:2007550

Development of mutated Kluyveromyces marxianus strains for ethanol production at elevated temperature from biomass hydrolysate

USDA-ARS?s Scientific Manuscript database

The yeast K. marxianus has advantages over the most commonly used industrial ethanologen, Saccharomyces cerevisiae, such as the ability to grow at 47°C, to produce ethanol at temperatures above 40°C, and to grow on a wide variety of substrates, including starch, sucrose, pectins, and cellulosic biom...

Synergistic cooperation promotes multicellular performance and unicellular free-rider persistence

PubMed Central

Driscoll, William W; Travisano, Michael

2017-01-01

The evolution of multicellular life requires cooperation among cells, which can be undermined by intra-group selection for selfishness. Theory predicts that selection to avoid non-cooperators limits social interactions among non-relatives, yet previous evolution experiments suggest that intra-group conflict is an outcome, rather than a driver, of incipient multicellular life cycles. Here we report the evolution of multicellularity via two distinct mechanisms of group formation in the unicellular budding yeast Kluyveromyces lactis. Cells remain permanently attached following mitosis, giving rise to clonal clusters (staying together); clusters then reversibly assemble into social groups (coming together). Coming together amplifies the benefits of multicellularity and allows social clusters to collectively outperform solitary clusters. However, cooperation among non-relatives also permits fast-growing unicellular lineages to ‘free-ride' during selection for increased size. Cooperation and competition for the benefits of multicellularity promote the stable coexistence of unicellular and multicellular genotypes, underscoring the importance of social and ecological context during the transition to multicellularity. PMID:28580966

Fructanase and fructosyltransferase activity of non-Saccharomyces yeasts isolated from fermenting musts of Mezcal.

PubMed

Arrizon, Javier; Morel, Sandrine; Gschaedler, Anne; Monsan, Pierre

2012-04-01

Fructanase and fructosyltransferase are interesting for the tequila process and prebiotics production (functional food industry). In this study, one hundred thirty non-Saccharomyces yeasts isolated from "Mezcal de Oaxaca" were screened for fructanase and fructosyltransferase activity. On solid medium, fifty isolates grew on Agave tequilana fructans (ATF), inulin or levan. In liquid media, inulin and ATF induced fructanase activities of between 0.02 and 0.27U/ml depending of yeast isolate. High fructanase activity on sucrose was observed for Kluyveromyces marxianus and Torulaspora delbrueckii, while the highest fructanase activity on inulin and ATF was observed for Issatchenkia orientalis, Cryptococcus albidus, and Candida apicola. Zygosaccharomyces bisporus and Candida boidinii had a high hydrolytic activity on levan. Sixteen yeasts belonging to K. marxianus, T. delbrueckii and C. apicola species were positive for fructosyltransferase activity. Mezcal microbiota proved to showed to be a source for new fructanase and fructosyltransferases with potential application in the tequila and food industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

The diversity of eukaryotic microbiota in the traditional Slovak sheep cheese--bryndza.

PubMed

Laurencík, M; Sulo, P; Sláviková, E; Piecková, E; Seman, M; Ebringer, L

2008-09-30

We investigated the occurrence and diversity of yeasts and filamentous fungi in bryndza an artisanal Slovak soft spreadable cheese prepared from raw sheep milk or from a mixture of sheep and cow milk. Samples collected during four months of the summer production period from two locations (northern and southern parts of central Slovakia) contained 10(5)-10(7) (cfu) yeasts and about 10(2) (cfu) of mold per gram of wet weight. Further characterization by conventional taxonomy and sequence comparison of D1/D2 region from 26S rRNA gene revealed Mucor circinelloides v. Tieghem as the predominant filamentous fungus. A novel Geotrichum sp. together with Kluyveromyces (K. lactis/K. marxianus) was identified as the most abundant yeast species. Occasionally other yeasts, such as Candida inconspicua, Candida silvae, Pichia fermentans and Trichosporon domesticum were found. Conventional taxonomy readily identified isolates to the genus level, but DNA sequence comparison was capable of discriminating them at the species level.

Fuel ethanol production from Jerusalem artichoke stalks using different yeasts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Margaritis, A.; Bajpai, P.; Bajpai, P.K.

1983-01-01

The inulin-type sugars present in the stalks of Jerusalem artichoke (Helianthus tuberosus) were extracted with hot water and were used as a substrate to produce fuel EtOH. Seven different yeasts were used to obtain batch kinetic data. The medium consisted of stalk extract from Jerusalem artichoke containing 7.3% total sugars, supplemented with 0.01% oleic acid, 0.01% corn steep liquor, and 0.05% Tween 80. All batch fermentations were carried out in a 1-L bioreactor at 35 degrees and pH 4.6, and the following parameters were measured as a function of time: total sugars, EtOH and biomass concentration, maximum specific growth rate,more » and biomass and EtOH yields. The best EtOH producer was Kluyveromyces marxianus UCD (FST) 55-82 which gave an EtOH-to-sugar yield 97% of the theoretical maximum value, with almost 100% sugar utilization.« less

Dynamics of yeast immobilized-cell fluidized-bed bioreactors systems in ethanol fermentation from lactose-hydrolyzed whey and whey permeate.

PubMed

Gabardo, Sabrina; Pereira, Gabriela Feix; Klein, Manuela P; Rech, Rosane; Hertz, Plinho F; Ayub, Marco Antônio Záchia

2016-01-01

We studied the dynamics of ethanol production on lactose-hydrolyzed whey (LHW) and lactose-hydrolyzed whey permeate (LHWP) in batch fluidized-bed bioreactors using single and co-cultures of immobilized cells of industrial strains of Saccharomyces cerevisiae and non-industrial strains of Kluyveromyces marxianus. Although the co-culture of S. cerevisiae CAT-1 and K. marxianus CCT 4086 produced two- to fourfold the ethanol productivity of single cultures of S. cerevisiae, the single cultures of the K. marxianus CCT 4086 produced the best results in both media (Y EtOH/S = 0.47-0.49 g g(-1) and Q P = 1.39-1.68 g L(-1) h(-1), in LHW and LHWP, respectively). Ethanol production on concentrated LHWP (180 g L(-1)) reached 79.1 g L(-1), with yields of 0.46 g g(-1) for K. marxianus CCT 4086 cultures. Repeated batches of fluidized-bed bioreactor on concentrated LHWP led to increased ethanol productivity, reaching 2.8 g L(-1) h(-1).

Phytase-producing capacity of yeasts isolated from traditional African fermented food products and PHYPk gene expression of Pichia kudriavzevii strains.

PubMed

Greppi, Anna; Krych, Łukasz; Costantini, Antonella; Rantsiou, Kalliopi; Hounhouigan, D Joseph; Arneborg, Nils; Cocolin, Luca; Jespersen, Lene

2015-07-16

Phytate is known as a strong chelate of minerals causing their reduced uptake by the human intestine. Ninety-three yeast isolates from traditional African fermented food products, belonging to nine species (Pichia kudriavzevii, Saccharomyces cerevisiae, Clavispora lusitaniae, Kluyveromyces marxianus, Millerozyma farinosa, Candida glabrata, Wickerhamomyces anomalus, Hanseniaspora guilliermondii and Debaryomyces nepalensis) were screened for phytase production on solid and liquid media. 95% were able to grow in the presence of phytate as sole phosphate source, P. kudriavzevii being the best growing species. A phytase coding gene of P. kudriavzevii (PHYPk) was identified and its expression was studied during growth by RT-qPCR. The expression level of PHYPk was significantly higher in phytate-medium, compared to phosphate-medium. In phytate-medium expression was seen in the lag phase. Significant differences in gene expression were detected among the strains as well as between the media. A correlation was found between the PHYPk expression and phytase extracellular activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of ultrasound on galactooligosaccharides and gluconic acid production throughout a multienzymatic system.

PubMed

Rico-Rodríguez, Fabián; Serrato, Juan Carlos; Montilla, Antonia; Villamiel, Mar

2018-06-01

Galactooligosaccharides (GOS), recognised prebiotic, can be industrially produced from lactose and commercial β-galactosidase (β-gal) from Kluyveromyces lactis. Residual lactose and glucose limit GOS applications. To handle this problem, a multienzymatic system, with β-gal and glucose oxidase (Gox), was proposed to reduce glucose content in reaction media through its oxidation to gluconic acid (GA). Besides, ultrasound (US) probe effect over the multienzymatic system to produce GOS and GA has been evaluated. A production around 40% of GOS was found in all treatments after the first hour of reaction. However, glucose consumption and GA production was significantly higher (P < 0.05) for sequential reaction assisted by US, obtaining the best production of GOS (49%) and GA (28%) after 2 h of reaction. The conformational and residual activity changes of enzymes under US conditions were also evaluated, Gox being positively affected whereas in β-gal hardly any change was found. Copyright © 2018 Elsevier B.V. All rights reserved.

Production of fermented cheese whey-based beverage using kefir grains as starter culture: evaluation of morphological and microbial variations.

PubMed

Magalhães, Karina Teixeira; Pereira, Maria Alcina; Nicolau, Ana; Dragone, Giuliano; Domingues, Lucília; Teixeira, José António; de Almeida Silva, João Batista; Schwan, Rosane Freitas

2010-11-01

Whey valorization concerns have led to recent interest on the production of whey beverage simulating kefir. In this study, the structure and microbiota of Brazilian kefir grains and beverages obtained from milk and whole/deproteinised whey was characterized using microscopy and molecular techniques. The aim was to evaluate its stability and possible shift of probiotic bacteria to the beverages. Fluorescence staining in combination with Confocal Laser Scanning Microscopy showed distribution of yeasts in macro-clusters among the grain's matrix essentially composed of polysaccharides (kefiran) and bacteria. Denaturing gradient gel electrophoresis displayed communities included yeast affiliated to Kluyveromyces marxianus, Saccharomyces cerevisiae, Kazachatania unispora, bacteria affiliated to Lactobacillus kefiranofaciens subsp. Kefirgranum, Lactobacillus kefiranofaciens subsp. Kefiranofaciens and an uncultured bacterium also related to the genus Lactobacillus. A steady structure and dominant microbiota, including probiotic bacteria, was detected in the analyzed kefir beverages and grains. This robustness is determinant for future implementation of whey-based kefir beverages.

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

PubMed

Escalante-Minakata, P; Blaschek, H P; Barba de la Rosa, A P; Santos, L; De León-Rodríguez, A

2008-06-01

To identify the yeast and bacteria present in the mezcal fermentation from Agave salmiana. 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. 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. We identified the community of bacteria and yeast present in mezcal fermentation from Agave salmiana.

Steam explosion treatment for ethanol production from branches pruned from pear trees by simultaneous saccharification and fermentation.

PubMed

Sasaki, Chizuru; Okumura, Ryosuke; Asada, Chikako; Nakamura, Yoshitoshi

2014-01-01

This study investigated the production of ethanol from unutilized branches pruned from pear trees by steam explosion pretreatment. Steam pressures of 25, 35, and 45 atm were applied for 5 min, followed by enzymatic saccharification of the extracted residues with cellulase (Cellic CTec2). High glucose recoveries, of 93.3, 99.7, and 87.1%, of the total sugar derived from the cellulose were obtained from water- and methanol-extracted residues after steam explosion at 25, 35, and 45 tm, respectively. These values corresponded to 34.9, 34.3, and 27.1 g of glucose per 100 g of dry steam-exploded branches. Simultaneous saccharification and fermentation experiments were done on water-extracted residues and water- and methanol-extracted residues by Kluyveromyces marxianus NBRC 1777. An overall highest theoretical ethanol yield of 76% of the total sugar derived from cellulose was achieved when 100 g/L of water- and methanol-washed residues from 35 atm-exploded pear branches was used as substrate.

Genetic instability of an oligomycin resistance mutation in yeast is associated with an amplification of a mitochondrial DNA segment.

PubMed Central

Ragnini, A; Fukuhara, H

1989-01-01

In the yeast Kluyveromyces lactis, mutations affecting mitochondrial functions are often highly unstable. In order to understand the basis of this genetic instability, we examined the case of an oligomycin resistant mutant. When the mutant was grown in the absence of the drug, the resistance was rapidly lost. This character showed a typical cytoplasmic inheritance. The unstable resistance was found to be associated with the presence of a repetitive DNA in which the repeating unit was a specific segment of the mitochondrial DNA. The amplified molecules were co-replicating with the wild type genome in the mutant cells. The spontaneous loss of the drug resistance was accompanied by the disappearance of the amplified DNA. The repetitive sequence came from a 405 base-pair segment immediately downstream of a cluster of two transfer RNA genes (threonyl 2 and glutamyl). Modified processing of these tRNAs was detected in the mutant. A possible mechanism by which these events could lead to drug resistance is discussed. Images PMID:2780315

Synthetic biology and molecular genetics in non-conventional yeasts: Current tools and future advances.

PubMed

Wagner, James M; Alper, Hal S

2016-04-01

Coupling the tools of synthetic biology with traditional molecular genetic techniques can enable the rapid prototyping and optimization of yeast strains. While the era of yeast synthetic biology began in the well-characterized model organism Saccharomyces cerevisiae, it is swiftly expanding to include non-conventional yeast production systems such as Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. These yeasts already have roles in the manufacture of vaccines, therapeutic proteins, food additives, and biorenewable chemicals, but recent synthetic biology advances have the potential to greatly expand and diversify their impact on biotechnology. In this review, we summarize the development of synthetic biological tools (including promoters and terminators) and enabling molecular genetics approaches that have been applied in these four promising alternative biomanufacturing platforms. An emphasis is placed on synthetic parts and genome editing tools. Finally, we discuss examples of synthetic tools developed in other organisms that can be adapted or optimized for these hosts in the near future. Copyright © 2015 Elsevier Inc. All rights reserved.

Soybean toxin (SBTX), a protein from soybeans that inhibits the life cycle of plant and human pathogenic fungi.

PubMed

Morais, Janne Keila S; Gomes, Valdirene M; Oliveira, José Tadeu A; Santos, Izabela S; Da Cunha, Maura; Oliveira, Hermogenes D; Oliveira, Henrique P; Sousa, Daniele O B; Vasconcelos, Ilka M

2010-10-13

Soybean toxin (SBTX) is a 44 kDa glycoprotein that is lethal to mice (LD(50) = 5.6 mg/kg). This study reports the toxicity of SBTX on pathogenic fungi and yeasts and the mechanism of its action. SBTX inhibited spore germination of Aspergillus niger and Penicillium herguei and was toxic to Candida albicans, Candida parapsilosis, Kluyveromyces marxiannus , Pichia membranifaciens, and Saccharomyces cerevisiae. In addition, SBTX hampered the growth of C. albicans and K. marxiannus and inhibited the glucose-stimulated acidification of the incubation medium by S. cerevisiae, suggesting that SBTX interferes with intracellular proton transport to the external medium. Moreover, SBTX caused cell-wall disruption, condensation/shrinkage of cytosol, pseudohyphae formation, and P. membranifaciens and C. parapsilosis cell death. SBTX is toxic to fungi at concentrations far below the dose lethal to mice and has potential in the design of new antifungal drugs or in the development of transgenic crops resistant to pathogens.

Prevalencia y factores de riesgo para infecciones del tracto urinario de inicio en la comunidad causadas por Escherichia coli productor de betalactamasas de espectro extendido en Colombia

PubMed Central

Blanco, Victor M.; Maya, Juan J.; Correa, Adriana; Perenguez, Marcela; Muñoz, Juan S.; Motoa, Gabriel; Pallares, Christian J.; Rosso, Fernando; Matta, Lorena; Celis, Yamile; Garzon, Martha; Villegas, y María V.

2016-01-01

RESUMEN Introducción Las infecciones del tracto urinario (ITU) son frecuentes en la comunidad. Sin embargo, la información de aislamientos resistentes en este contexto es limitada en Latinoamérica. Este estudio tiene como objetivo determinar la prevalencia y los factores de riesgo asociados con ITU de inicio en la comunidad (ITU-IC) causadas por Escherichia coli productor de betalactamasas de espectro extendido (BLEE) en Colombia. Materiales y métodos Entre agosto y diciembre de 2011 se realizó un estudio de casos y controles en 3 instituciones de salud de tercer nivel en Colombia. Se invitó a participar a todos los pacientes admitidos a urgencias con diagnóstico probable de ITU-IC, y se les pidió una muestra de orina. En los aislamien-tos de E. coli se realizaron pruebas confirmatorias para BLEE, susceptibilidad antibiótica, caracterización molecular (PCR en tiempo real para genes bla, repetitive element palindromic PCR [rep-PCR], multilocus sequence typing [MLST] y factores de virulencia por PCR). Se obtuvo información clínica y epidemiológica, y posteriormente se realizó el análisis estadístico. Resultados De los 2.124 pacientes seleccionados, 629 tuvieron un urocultivo positivo, en 431 de estos se aisló E. coli, 54 fueron positivos para BLEE y 29 correspondieron a CTX-M-15. La mayoría de los aislamientos de E. coli productor de BLEE fueron sensibles a ertapenem, fosfomicina y amikacina. La ITU complicada se asoció fuertemente con infecciones por E. coli productor de BLEE (OR = 3,89; IC 95%: 1,10–13,89; p = 0,03). E. coli productor de CTX-M-15 mostró 10 electroferotipos diferentes; de estos, el 65% correspondieron al ST131. La mayoría de estos aislamientos tuvieron 8 de los 9 factores de virulencia analizados. Discusión E. coli portador del gen blaCTX-M-15 asociado al ST131 sigue siendo frecuente en Colombia. La presencia de ITU-IC complicada aumenta el riesgo de tener E. coli productor de BLEE, lo cual debe tenerse en cuenta para ofrecer

La inserción en el mercado laboral de los inmigrantes latinos en España y en los Estados Unidos: Diferencias por país de origen y estatus legal

PubMed Central

Connor, Phillip; Massey, Douglas

2013-01-01

Resumen Este artículo compara los resultados económicos entre los inmigrantes latinoamericanos en España y Estados Unidos. Detectamos un efecto de selección por el que la mayoría de los inmigrantes latinoamericanos en España proceden de Sudamérica de un entorno de clases medias, mientras la mayoría de los inmigrantes que van a los Estados Unidos son centroamericanos de clase baja. Este efecto de selección explica las diferencias transnacionales en la probabilidad de empleo, logro ocupacional y salarios obtenidos. A pesar de las diferencias en los orígenes y las características de los latinoamericanos en ambos países, los factores demográficos, humanos y de capital social parecen operar de forma similar en ambos países; y cuando los modelos se estiman separadamente por estatus legal, descubrimos que los efectos se acentúan más entre los inmigrantes irregulares cuando se los compara con los regulares, especialmente en Estados Unidos. PMID:24532857

"Estudio tribologico de aceros para moldes. Aplicacion al moldeo por inyeccion de polibutilentereftalato reforzado con fibra de vidrio"

NASA Astrophysics Data System (ADS)

Martinez Mateo, Isidoro Jose

Mould materials for injection moulding of polymers and polymer-matrix composites represent a relevant industrial economic sector due to the large quantity of pieces and components processed. The material selection for mould manufacturing, its composition and heat treatment, the hardening procedures and machining and finishing processes determine the service performance and life of the mould. In the first part of the present study, the relationship between the hardness and microstructure and the wear resistance of mould steels from large blocks has been studied by pin-on-disc tests, studying the main wear mechanisms. In order to determine the surface damage on mould steels under real injection conditions, different commercial steels have been studied by measuring the variation of surface roughness with the number of injected pieces with different reinforcement percentages and different mould geometries, by using optical profilometry and scanning electron microscopy techniques. It was important to determine the variation of surface roughness of the moulded pieces with the number of injection operations. The materials used were polybutyleneterephthalate pure and reinforced with either 20% or 50% glass fibre. For the different mould designs, the evolution of the glass fibre orientation with injection flow has been determined by image analysis and related to roughness changes and surface damage, both of the composite parts and of the mould steel surface. Finally, the abrasion resistance of the composite parts has been studied by scratch tests as a function of the number of injected parts and of the scratch direction with respect to injection flow and glass fibre orientation. Los materiales para moldes de inyeccion de polimeros y materiales compuestos representan un sector economicamente muy relevante debido al gran aumento del numero de componentes fabricados a partir de materiales polimericos obtenidos mediante moldeo por inyeccion. La seleccion del material para la

Mujeres felices por ser saludables: a breast cancer risk reduction program for Latino women.

PubMed

Fitzgibbon, Marian L; Gapstur, Susan M; Knight, Sara J

2003-05-01

Breast cancer is the most commonly diagnosed cancer and the most common cause of cancer mortality among Latino women. Several behavioral factors such as early detection and dietary practices could help decrease morbidity and mortality associated with breast cancer in this population. Unfortunately, there are few data regarding the efficacy of health-related interventions for young Latino women. Mujeres Felices por ser Saludables is a randomized intervention project designed to assess breast cancer risk reduction behavior among Latino women ages 20-40 years. The primary objectives of the project were to determine whether an 8-month integrated dietary/breast health intervention could lead to a greater reduction in dietary fat, increase in dietary fiber, increase in the frequency and proficiency of breast self examination (BSE), and reduction in anxiety related to BSE compared to controls. Herein we describe the overall design of the project and present baseline characteristics of the 256 randomized women. Our results suggest that the average daily intake of dietary fat (percentage of total energy) was slightly below 30% (percentage of total energy) among the women randomized. While over half of these women reported that they practice BSE, and few reported anxiety related to BSE, less than 27% of women were proficient in the recommended BSE technique. There are few data on the dietary and breast health behaviors of young low-acculturated Latino women. This study documents the feasibility of recruiting, randomizing, and obtaining both baseline dietary and breast health data on this unique and underserved population.

Relación masa-radio para estrellas enanas blancas y la interpretación de recientes mediciones hechas por Hipparcos

NASA Astrophysics Data System (ADS)

Panei, J. A.; Althaus, L. G.; Benvenuto, O. G.

Recientes mediciones de la masa y el radio hechas por Hipparcos de las estrellas enanas blancas 40 Eri B y Procyon B (Shipman, H. & Provencal, J. - ApJ. 1998, 494, 759), sugieren un núcleo compuesto de hierro para dichas estrellas, en lugar de carbono y oxígeno como predice la teoría standard de evolución estelar. Para interpretar estas observaciones, presentamos aquí, relaciones masa-radio para configuraciones degeneradas a temperatura finita para distintas composiciones químicas centrales. Para tal fin hemos calculado secuencias evolutivas de enanas blancas utilizando el código de evolución estelar, desarrollado en el Observatorio de La Plata. Dicho código resuelve las ecuaciones de estructura y evolución estelar mediante la técnica de relajación de Henyey, y esta basado en una descripción física muy detallada y actualizada.

Relationship of CYP2D6, CYP3A, POR, and ABCB1 genotypes with galantamine plasma concentrations.

PubMed

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Zumbach, Serge; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2013-04-01

The frequently prescribed antidementia drug galantamine is extensively metabolized by the enzymes cytochrome P450 (CYP) 2D6 and CYP3A and is a substrate of the P-glycoprotein. We aimed to study the relationship between genetic variants influencing the activity of these enzymes and transporters with galantamine steady state plasma concentrations. In this naturalistic cross-sectional study, 27 older patients treated with galantamine were included. The patients were genotyped for common polymorphisms in CYP2D6, CYP3A4/5, POR, and ABCB1, and galantamine steady state plasma concentrations were determined. The CYP2D6 genotype seemed to be an important determinant of galantamine pharmacokinetics, with CYP2D6 poor metabolizers presenting 45% and 61% higher dose-adjusted galantamine plasma concentrations than heterozygous and homozygous CYP2D6 extensive metabolizers (median 2.9 versus 2.0 ng/mL · mg, P = 0.025, and 1.8 ng/mL · mg, P = 0.004), respectively. The CYP2D6 genotype significantly influenced galantamine plasma concentrations. The influence of CYP2D6 polymorphisms on the treatment efficacy and tolerability should be further investigated.

The Sangre Por Salud Biobank: Facilitating Genetic Research in an Underrepresented Latino Community.

PubMed

Shaibi, Gabriel; Singh, Davinder; De Filippis, Eleanna; Hernandez, Valentina; Rosenfeld, Bill; Otu, Essen; Montes de Oca, Gregorio; Levey, Sharon; Radecki Breitkopf, Carmen; Sharp, Richard; Olson, Janet; Cerhan, James; Thibodeau, Stephen; Winkler, Erin; Mandarino, Lawrence

2016-01-01

The Sangre Por Salud (Blood for Health; SPS) Biobank was created for the purpose of expanding precision medicine research to include underrepresented Latino patients. It is the result of a unique collaboration between Mayo Clinic and Mountain Park Health Center, a federally qualified community health center in Phoenix, Arizona. This report describes the rationale, development, implementation, and characteristics of the SPS Biobank. Latino adults (ages 18-85 years) who were active patients within Mountain Park Health Center's internal medicine practice in Phoenix, Ariz., and had no history of diabetes were eligible. Participants provided a personal and family history of chronic disease, completed a sociodemographic, psychosocial, and behavioral questionnaire, underwent a comprehensive cardiometabolic risk assessment (anthropometrics, blood pressure and labs), and provided blood samples for banking. Laboratory results of cardiometabolic testing were returned to the participants and their providers through the electronic health record. During the first 2 years of recruitment into the SPS Biobank, 2,335 patients were approached and 1,432 (61.3%) consented to participate; 1,354 (94.5%) ultimately completed all requisite questionnaires and medical evaluations. The cohort is primarily Spanish-speaking (72.9%), female (73.3%), with a mean age of 41.3 ± 12.5 years. Most participants were born outside of the US (77.9%) and do not have health insurance (77.5%). The prevalence of overweight (35.5%) and obesity (45.0%) was high, as was previously unidentified prediabetes (55.9%), type 2 diabetes (7.4%), prehypertension (46.8%), and hypertension (16.2%). The majority of participants rated their health as good to excellent (72.1%) and, as a whole, described their overall quality of life as high (7.9/10). Collaborative efforts such as the SPS Biobank are critical for ensuring that underrepresented minority populations are included in precision medicine initiatives and biomedical

The Sangre Por Salud Biobank: Facilitating Genetic Research in an Underrepresented Latino Community

PubMed Central

Shaibi, Gabriel; Singh, Davinder; De Filippis, Eleanna; Hernandez, Valentina; Rosenfeld, Bill; Otu, Essen; de Oca, Gregorio Montes; Levey, Sharon; Breitkopf, Carmen Radecki; Sharp, Richard; Olson, Janet; Cerhan, James; Thibodeau, Stephen; Winkler, Erin; Mandarino, Lawrence

2018-01-01

Background/Aims The Sangre Por Salud (Blood for Health; SPS) Biobank was created for the purpose of expanding precision medicine research to include underrepresented Latino patients. It is the result of a unique collaboration between Mayo Clinic and Mountain Park Health Center, a federally qualified community health center in Phoenix, Arizona. This report describes the rationale, development, implementation, and characteristics of the SPS Biobank. Methods Latino adults (ages 18–85 years) who were active patients within Mountain Park Health Center’s internal medicine practice in Phoenix, Ariz., and had no history of diabetes were eligible. Participants provided a personal and family history of chronic disease, completed a sociodemographic, psychosocial, and behavioral questionnaire, underwent a comprehensive cardiometabolic risk assessment (anthropometrics, blood pressure and labs), and provided blood samples for banking. Laboratory results of cardiometabolic testing were returned to the participants and their providers through the electronic health record. Results During the first 2 years of recruitment into the SPS Biobank, 2,335 patients were approached and 1,432 (61.3%) consented to participate; 1,354 (94.5%) ultimately completed all requisite questionnaires and medical evaluations. The cohort is primarily Spanish-speaking (72.9%), female (73.3%), with a mean age of 41.3 ± 12.5 years. Most participants were born outside of the US (77.9%) and do not have health insurance (77.5%). The prevalence of overweight (35.5%) and obesity (45.0%) was high, as was previously unidentified prediabetes (55.9%), type 2 diabetes (7.4%), prehypertension (46.8%), and hypertension (16.2%). The majority of participants rated their health as good to excellent (72.1%) and, as a whole, described their overall quality of life as high (7.9/10). Conclusion Collaborative efforts such as the SPS Biobank are critical for ensuring that underrepresented minority populations are included in

The occurrence and growth of yeasts in Camembert and blue-veined cheeses.

PubMed

Roostita, R; Fleet, G H

1996-01-01

Yeast populations greater than 10(6) cfu/g were found in approximately 54% and 36%, respectively in surface samples of retail Camembert (85 samples) and Blue-veined (45 samples) cheeses. The most predominant species isolated were Debaryomyces hansenii, Candida catenulata, C. lipolytica, C. kefyr, C. intermedia, Saccharomyces cerevisiae, Cryptococcus albidus and Kluyveromyces marxianus. The salt concentration of the surface samples of the cheeses varied between 2.5-5.5% (w/w) (Camembert) and 7.5-8.3 (Blue-veined), depending upon brand, and influenced the yeast ecology, especially the presence of S. cerevisiae. Yeasts grew to populations of 10(6)-10(8) cfu/g when cheeses were stored at either 25 degrees C or 10 degrees C. These populations decreased on continued storage at 25 degrees C, but such decreases were not so evident on storage at 10 degrees C. The properties of yeasts influencing their occurrence and growth in cheese were: fermentation/assimilation of lactose; production of extracellular lipolytic and proteolytic enzymes, utilisation of lactic and citric acids; and growth at 10 degrees C.

Construction of a lactose-assimilating strain of baker's yeast.

PubMed

Adam, A C; Prieto, J A; Rubio-Texeira, M; Polaina, J

1999-09-30

A recombinant strain of baker's yeast has been constructed which can assimilate lactose efficiently. This strain has been designed to allow its propagation in whey, the byproduct resulting from cheese-making. The ability to metabolize lactose is conferred by the functional expression of two genes from Kluyveromyces lactis, LAC12 and LAC4, which encode a lactose permease and a beta-galactosidase, respectively. To make the recombinant strain more acceptable for its use in bread-making, the genetic transformation of the host baker's yeast was carried out with linear fragments of DNA of defined sequence, carrying as the only heterologous material the coding regions of the two K. lactis genes. Growth of the new strain on cheese whey affected neither the quality of bread nor the yeast gassing power. The significance of the newly developed strain is two-fold: it affords a cheap alternative to the procedure generally used for the propagation of baker's yeast, and it offers a profitable use for cheese whey. Copyright 1999 John Wiley & Sons, Ltd.

Structure-function insights into direct lipid transfer between membranes by Mmm1-Mdm12 of ERMES.

PubMed

Kawano, Shin; Tamura, Yasushi; Kojima, Rieko; Bala, Siqin; Asai, Eri; Michel, Agnès H; Kornmann, Benoît; Riezman, Isabelle; Riezman, Howard; Sakae, Yoshitake; Okamoto, Yuko; Endo, Toshiya

2018-03-05

The endoplasmic reticulum (ER)-mitochondrial encounter structure (ERMES) physically links the membranes of the ER and mitochondria in yeast. Although the ER and mitochondria cooperate to synthesize glycerophospholipids, whether ERMES directly facilitates the lipid exchange between the two organelles remains controversial. Here, we compared the x-ray structures of an ERMES subunit Mdm12 from Kluyveromyces lactis with that of Mdm12 from Saccharomyces cerevisiae and found that both Mdm12 proteins possess a hydrophobic pocket for phospholipid binding. However in vitro lipid transfer assays showed that Mdm12 alone or an Mmm1 (another ERMES subunit) fusion protein exhibited only a weak lipid transfer activity between liposomes. In contrast, Mdm12 in a complex with Mmm1 mediated efficient lipid transfer between liposomes. Mutations in Mmm1 or Mdm12 impaired the lipid transfer activities of the Mdm12-Mmm1 complex and furthermore caused defective phosphatidylserine transport from the ER to mitochondrial membranes via ERMES in vitro. Therefore, the Mmm1-Mdm12 complex functions as a minimal unit that mediates lipid transfer between membranes. © 2018 Kawano et al.

Structure of yeast Argonaute with guide RNA

PubMed Central

Nakanishi, Kotaro; Weinberg, David E.; Bartel, David P.; Patel, Dinshaw J.

2012-01-01

The RNA-induced silencing complex, comprising Argonaute and guide RNA, mediates RNA interference. Here we report the 3.2 Å crystal structure of Kluyveromyces Argonaute (KpAGO) fortuitously complexed with guide RNA originating from small-RNA duplexes autonomously loaded and processed by recombinant KpAGO. Despite their diverse sequences, guide-RNA nucleotides 1–8 are positioned similarly, with sequence-independent contacts to bases, phosphates and 2′-hydroxyl groups pre-organizing the backbone of nucleotides 2–8 in a near–A-form conformation. Compared with prokaryotic Argonautes, KpAGO has numerous surface-exposed insertion segments, with a cluster of conserved insertions repositioning the N domain to enable full propagation of guide–target pairing. Compared with Argonautes in inactive conformations, KpAGO has a hydrogen-bond network that stabilizes an expanded and repositioned loop, which inserts an invariant glutamate into the catalytic pocket. Mutation analyses and analogies to Ribonuclease H indicate that insertion of this glutamate finger completes a universally conserved catalytic tetrad, thereby activating Argonaute for RNA cleavage. PMID:22722195

Cellulose Biorefinery Based on a Combined Catalytic and Biotechnological Approach for Production of 5-HMF and Ethanol.

PubMed

Sorokina, Ksenia N; Taran, Oxana P; Medvedeva, Tatiana B; Samoylova, Yuliya V; Piligaev, Alexandr V; Parmon, Valentin N

2017-02-08

In this study, a combination of catalytic and biotechnological processes was proposed for the first time for application in a cellulose biorefinery for the production of 5-hydroxymethylfurfural (5-HMF) and bioethanol. Hydrolytic dehydration of the mechanically activated microcrystalline cellulose over a carbon-based mesoporous Sibunt-4 catalyst resulted in moderate yields of glucose and 5-HMF (21.1-25.1 and 6.6-9.4 %). 5-HMF was extracted from the resulting mixture with isobutanol and subjected to ethanol fermentation. A number of yeast strains were isolated that also revealed high thermotolerance (up to 50 °C) and resistance to inhibitors found in the hydrolysates. The strains Kluyveromyces marxianus C1 and Ogataea polymorpha CBS4732 were capable of producing ethanol from processed catalytic hydrolysates of cellulose at 42 °C, with yields of 72.0±5.7 and 75.2±4.3 % from the maximum theoretical yield of ethanol, respectively. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The evolution of Lachancea thermotolerans is driven by geographical determination, anthropisation and flux between different ecosystems

PubMed Central

Bely, Marina; Masneuf-Pomarede, Isabelle; Jiranek, Vladimir; Albertin, Warren

2017-01-01

The yeast Lachancea thermotolerans (formerly Kluyveromyces thermotolerans) is a species with remarkable, yet underexplored, biotechnological potential. This ubiquist occupies a range of natural and anthropic habitats covering a wide geographic span. To gain an insight into L. thermotolerans population diversity and structure, 172 isolates sourced from diverse habitats worldwide were analysed using a set of 14 microsatellite markers. The resultant clustering revealed that the evolution of L. thermotolerans has been driven by the geography and ecological niche of the isolation sources. Isolates originating from anthropic environments, in particular grapes and wine, were genetically close, thus suggesting domestication events within the species. The observed clustering was further validated by several means including, population structure analysis, F-statistics, Mantel’s test and the analysis of molecular variance (AMOVA). Phenotypic performance of isolates was tested using several growth substrates and physicochemical conditions, providing added support for the clustering. Altogether, this study sheds light on the genotypic and phenotypic diversity of L. thermotolerans, contributing to a better understanding of the population structure, ecology and evolution of this non-Saccharomyces yeast. PMID:28910346

DOE Office of Scientific and Technical Information (OSTI.GOV)

J Chang; S Xiang; K Xiang

The 5' {yields} 3' exoribonucleases (XRNs) have important functions in transcription, RNA metabolism and RNA interference. The structure of Rat1 (also known as Xrn2) showed that the two highly conserved regions of XRNs form a single, large domain that defines the active site of the enzyme. Xrn1 has a 510-residue segment after the conserved regions that is required for activity but is absent from Rat1/Xrn2. Here we report the crystal structures of Kluyveromyces lactis Xrn1 (residues 1-1,245, E178Q mutant), alone and in complex with a Mn{sup 2+} ion in the active site. The 510-residue segment contains four domains (D1-D4), locatedmore » far from the active site. Our mutagenesis and biochemical studies show that their functional importance results from their ability to stabilize the conformation of the N-terminal segment of Xrn1. These domains might also constitute a platform that interacts with protein partners of Xrn1.« less

Fragile genomic sites are associated with origins of replication.

PubMed

Di Rienzi, Sara C; Collingwood, David; Raghuraman, M K; Brewer, Bonita J

2009-09-09

Genome rearrangements are mediators of evolution and disease. Such rearrangements are frequently bounded by transfer RNAs (tRNAs), transposable elements, and other repeated elements, suggesting a functional role for these elements in creating or repairing breakpoints. Though not well explored, there is evidence that origins of replication also colocalize with breakpoints. To investigate a potential correlation between breakpoints and origins, we analyzed evolutionary breakpoints defined between Saccharomyces cerevisiae and Kluyveromyces waltii and S. cerevisiae and a hypothetical ancestor of both yeasts, as well as breakpoints reported in the experimental literature. We find that origins correlate strongly with both evolutionary breakpoints and those described in the literature. Specifically, we find that origins firing earlier in S phase are more strongly correlated with breakpoints than are later-firing origins. Despite origins being located in genomic regions also bearing tRNAs and Ty elements, the correlation we observe between origins and breakpoints appears to be independent of these genomic features. This study lays the groundwork for understanding the mechanisms by which origins of replication may impact genome architecture and disease.

Genetic, genomic, and molecular tools for studying the protoploid yeast, L. waltii.

PubMed

Di Rienzi, Sara C; Lindstrom, Kimberly C; Lancaster, Ragina; Rolczynski, Lisa; Raghuraman, M K; Brewer, Bonita J

2011-02-01

Sequencing of the yeast Kluyveromyces waltii (recently renamed Lachancea waltii) provided evidence of a whole genome duplication event in the lineage leading to the well-studied Saccharomyces cerevisiae. While comparative genomic analyses of these yeasts have proven to be extremely instructive in modeling the loss or maintenance of gene duplicates, experimental tests of the ramifications following such genome alterations remain difficult. To transform L. waltii from an organism of the computational comparative genomic literature into an organism of the functional comparative genomic literature, we have developed genetic, molecular and genomic tools for working with L. waltii. In particular, we have characterized basic properties of L. waltii (growth, ploidy, molecular karyotype, mating type and the sexual cycle), developed transformation, cell cycle arrest and synchronization protocols, and have created centromeric and non-centromeric vectors as well as a genome browser for L. waltii. We hope that these tools will be used by the community to follow up on the ideas generated by sequence data and lead to a greater understanding of eukaryotic biology and genome evolution. 2010 John Wiley & Sons, Ltd.

Genetic, genomic, and molecular tools for studying the protoploid yeast, L. waltii

PubMed Central

Di Rienzi, Sara C.; Lindstrom, Kimberly C.; Lancaster, Ragina; Rolczynski, Lisa; Raghuraman, M. K.; Brewer, Bonita J.

2011-01-01

Sequencing of the yeast Kluyveromyces waltii (recently renamed Lachancea waltii) provided evidence of a whole genome duplication event in the lineage leading to the well-studied Saccharomyces cerevisiae. While comparative genomic analyses of these yeasts have proven to be extremely instructive in modeling the loss or maintenance of gene duplicates, experimental tests of the ramifications following such genome alterations remain difficult. To transform L. waltii from an organism of the computational comparative genomic literature into an organism of the functional comparative genomic literature, we have developed genetic, molecular and genomic tools for working with L. waltii. In particular, we have characterized basic properties of L. waltii (growth, ploidy, molecular karyotype, mating type and the sexual cycle), developed transformation, cell cycle arrest and synchronization protocols, and have created centromeric and non-centromeric vectors as well as a genome browser for L. waltii. We hope that these tools will be used by the community to follow up on the ideas generated by sequence data and lead to a greater understanding of eukaryotic biology and genome evolution. PMID:21246627

Evaluation of Galactose Adapted Yeasts for Bioethanol Fermentation from Kappaphycus alvarezii Hydrolyzates.

PubMed

Nguyen, Trung Hau; Ra, Chae Hun; Sunwoo, In Yung; Jeong, Gwi-Taek; Kim, Sung-Koo

2016-07-28

Bioethanol was produced from Kappaphycus alvarezii seaweed biomass using separate hydrolysis and fermentation (SHF). Pretreatment was evaluated for 60 min at 121°C using 12% (w/v) biomass slurry with 364 mM H2SO4. Enzymatic saccharification was then carried out at 45°C for 48 h using Celluclast 1.5 L. Ethanol fermentation with 12% (w/v) K. alvarezii hydrolyzate was performed using the yeasts Saccharomyces cerevisiae KCTC1126, Kluyveromyces marxianus KCTC7150, and Candida lusitaniae ATCC42720 with or without prior adaptation to high concentrations of galactose. When non-adapted S. cerevisiae, K. marxianus, and C. lusitaniae were used, 11.5 g/l, 6.7 g/l, and 6.0 g/l of ethanol were produced, respectively. When adapted S. cerevisiae, K. marxianus, and C. lusitaniae were used, 15.8 g/l, 11.6 g/l, and 13.4 g/l of ethanol were obtained, respectively. The highest ethanol concentration was 15.8 g/l, with YEtOH = 0.43 and YT% = 84.3%, which was obtained using adapted S. cerevisiae.

Evaluation of hyper thermal acid hydrolysis of Kappaphycus alvarezii for enhanced bioethanol production.

PubMed

Ra, Chae Hun; Nguyen, Trung Hau; Jeong, Gwi-Taek; Kim, Sung-Koo

2016-06-01

Hyper thermal (HT) acid hydrolysis of Kappaphycus alvarezii, a red seaweed, was optimized to 12% (w/v) seaweed slurry content, 180mM H2SO4 at 140°C for 5min. The maximum monosaccharide concentration of 38.3g/L and 66.7% conversion from total fermentable monosaccharides of 57.6g/L with 120gdw/L K. alvarezii slurry were obtained from HT acid hydrolysis and enzymatic saccharification. HT acid hydrolysis at a severity factor of 0.78 efficiently converted the carbohydrates of seaweed to monosaccharides and produced a low concentration of inhibitory compounds. The levels of ethanol production by separate hydrolysis and fermentation with non-adapted and adapted Kluyveromyces marxianus to high concentration of galactose were 6.1g/L with ethanol yield (YEtOH) of 0.19 at 84h and 16.0g/L with YEtOH of 0.42 at 72h, respectively. Development of the HT acid hydrolysis process and adapted yeast could enhance the overall ethanol fermentation yields of K. alvarezii seaweed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioethanol production from Scenedesmus obliquus sugars: the influence of photobioreactors and culture conditions on biomass production.

PubMed

Miranda, J R; Passarinho, P C; Gouveia, L

2012-10-01

A closed-loop vertical tubular photobioreactor (PBR), specially designed to operate under conditions of scarce flat land availability and irregular solar irradiance conditions, was used to study the potential of Scenedesmus obliquus biomass/sugar production. The results obtained were compared to those from an open-raceway pond and a closed-bubble column. The influence of the type of light source and the regime (natural vs artificial and continuous vs light/dark cycles) on the growth of the microalga and the extent of the sugar accumulation was studied in both PBRs. The best type of reactor studied was a closed-loop PBR illuminated with natural light/dark cycles. In all the cases, the relationship between the nitrate depletion and the sugar accumulation was observed. The microalga Scenedesmus was cultivated for 53 days in a raceway pond (4,500 L) and accumulated a maximum sugar content of 29 % g/g. It was pre-treated for carrying out ethanol fermentation assays, and the highest ethanol concentration obtained in the hydrolysate fermented by Kluyveromyces marxianus was 11.7 g/L.

Mitochondrial Genome Integrity Mutations Uncouple the Yeast Saccharomyces cerevisiae ATP Synthase*║

PubMed Central

Wang, Yamin; Singh, Usha; Mueller, David M.

2013-01-01

The mitochondrial ATP synthase is a molecular motor, which couples the flow of rotons with phosphorylation of ADP. Rotation of the central stalk within the core of ATP synthase effects conformational changes in the active sites driving the synthesis of ATP. Mitochondrial genome integrity (mgi) mutations have been previously identified in the α-, β-, and γ-subunits of ATP synthase in yeast Kluyveromyces lactis and trypanosome Trypanosoma brucei. These mutations reverse the lethality of the loss of mitochondrial DNA in petite negative strains. Introduction of the homologous mutations in Saccharomyces cerevisiae results in yeast strains that lose mitochondrial DNA at a high rate and accompanied decreases in the coupling of the ATP synthase. The structure of yeast F1-ATPase reveals that the mgi residues cluster around the γ-subunit and selectively around the collar region of F1. These results indicate that residues within the mgi complementation group are necessary for efficient coupling of ATP synthase, possibly acting as a support to fix the axis of rotation of the central stalk. PMID:17244612

Utilization of whey powder as substrate for low-cost preparation of β-galactosidase as main product, and ethanol as by-product, by a litre-scale integrated process.

PubMed

You, Shengping; Chang, Hongxing; Yin, Qingdian; Qi, Wei; Wang, Mengfan; Su, Rongxin; He, Zhimin

2017-12-01

Whey powder, a by-product of dairy industry, is an attractive raw material for value-added products. In this study, utilization of whey powder as substrate for low-cost preparation of β-galactosidase as main product and ethanol as by-product were investigated by a litre-scale integrated strategy, encompassing fermentation, isolation, permeabilization and spray drying. Firstly, through development of low-cost industrial culture and fed-batch strategies by Kluyveromyces lactis, 119.30U/mL β-galactosidase activity and 16.96mg/mL by-product ethanol were achieved. Afterward, an up-dated mathematic model for the recycling permeabilization was established successfully and 30.4g cells sediment isolated from 5L fermentation broth were permeabilized completely by distilled ethanol from broth supernatant. Then β-galactosidase product with 5.15U/mg from protection of gum acacia by spray drying was obtained. Furthermore, by-product ethanol with 31.08% (v/v) was achieved after permeabilization. Therefore, the integrated strategy using whey powder as substrate is a feasible candidate for industrial-scale implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Respiration-dependent utilization of sugars in yeasts: a determinant role for sugar transporters.

PubMed

Goffrini, Paola; Ferrero, Iliana; Donnini, Claudia

2002-01-01

In many yeast species, including Kluyveromyces lactis, growth on certain sugars (such as galactose, raffinose, and maltose) occurs only under respiratory conditions. If respiration is blocked by inhibitors, mutation, or anaerobiosis, growth does not take place. This apparent dependence on respiration for the utilization of certain sugars has often been suspected to be associated with the mechanism of the sugar uptake step. We hypothesized that in many yeast species, the permease activities for these sugars are not sufficient to ensure the high substrate flow that is necessary for fermentative growth. By introducing additional sugar permease genes, we have obtained K. lactis strains that were capable of growing on galactose and raffinose in the absence of respiration. High dosages of both the permease and maltase genes were indeed necessary for K. lactis cells to grow on maltose in the absence of respiration. These results strongly suggest that the sugar uptake step is the major bottleneck in the fermentative assimilation of certain sugars in K. lactis and probably in many other yeasts.

Respiration-Dependent Utilization of Sugars in Yeasts: a Determinant Role for Sugar Transporters

PubMed Central

Goffrini, Paola; Ferrero, Iliana; Donnini, Claudia

2002-01-01

In many yeast species, including Kluyveromyces lactis, growth on certain sugars (such as galactose, raffinose, and maltose) occurs only under respiratory conditions. If respiration is blocked by inhibitors, mutation, or anaerobiosis, growth does not take place. This apparent dependence on respiration for the utilization of certain sugars has often been suspected to be associated with the mechanism of the sugar uptake step. We hypothesized that in many yeast species, the permease activities for these sugars are not sufficient to ensure the high substrate flow that is necessary for fermentative growth. By introducing additional sugar permease genes, we have obtained K. lactis strains that were capable of growing on galactose and raffinose in the absence of respiration. High dosages of both the permease and maltase genes were indeed necessary for K. lactis cells to grow on maltose in the absence of respiration. These results strongly suggest that the sugar uptake step is the major bottleneck in the fermentative assimilation of certain sugars in K. lactis and probably in many other yeasts. PMID:11751819

Continuous production of pectinase by immobilized yeast cells on spent grains.

PubMed

Almeida, Catarina; Brányik, Tomás; Moradas-Ferreira, Pedro; Teixeira, José

2003-01-01

A yeast strain secreting endopolygalacturonase was used in this work to study the possibility of continuous production of this enzyme. It is a feasible and interesting alternative to fungal batch production essentially due to the specificity of the type of pectinase excreted by Kluyveromyces marxianus CCT 3172, to the lower broth viscosity and to the easier downstream operations. In order to increase the reactors' productivity, a cellulosic carrier obtained from barley spent grains was tested as an immobilization support. Two types of reactors were studied for pectinase production using glucose as a carbon and energy source--a continuous stirred tank reactor (CSTR) and a packed bed reactor (PBR) with recycled flow. The highest value for pectinase volumetric productivity (P(V)=0.98 U ml(-1) h(-1)) was achieved in the PBR for D=0.40 h(-1), a glucose concentration on the inlet of S(in)=20 g l(-1), and a biomass load in the support of X(i)=0.225 g g(-1). The results demonstrate the attractiveness of the packed bed system for pectinase production.

Astronomy in the Classroom: Why? (Spanish Title: Astronomía en la Clase: ¿Por Qué?) Astronomia na Sala de Aula: Por Quê?

NASA Astrophysics Data System (ADS)

Daros Gama, Leandro; Bagdonas Henrique, Alexandre

2010-07-01

There are many discussions about the relevance of the topics covered in classes. One subject in particular is the focus of this essay: astronomy. In what sense and to what extent it would be worth to teach it in science or other kind of classes? In this paper we discuss some aspects of the advantages of dealing with this area of knowledge in schools, taking into account the epistemological and axiological dimensions of astronomy, in light of the vision of science as an intelligent dialogue with the world (Bachelard), in addition to the "problematization" knowledge of Paulo Freire. We propose that in fact the Astronomy does not need to be seen as just a new set of contents to be taught, but appears as a set of motivational contents for historical-philosophical discussions, and permit the discussion of concepts of other disciplines. Numerosas discusiones se están llevando a cabo acerca de la pertinencia de los temas tradicionalmente tratados en las clases. Uno de los temas, en particular, es el foco de este ensayo: la astronomía. ¿En qué sentido y en qué medida sería conveniente tratarla en clase, ya sea en clases de ciencias naturales, específicamente en las de astronomía o asignaturas afines? Elaboramos en este artículo algunos aspectos de las ventajas de tratar esta área del conocimiento en las escuelas, teniendo en cuenta las dimensiones epistemológica y axiológica de la astronomía, a la luz de la visión de la ciencia como un diálogo inteligente con el mundo (Bachelard), además de la propuesta del conocimiento "problematizador" de Paulo Freire. Proponemos que en realidad la astronomía no tiene por qué ser vista sólo como un nuevo conjunto de contenidos que se enseñan, sino que aparece como un conjunto de temas de motivación para el debate histórico-filosófico y para permitir la discusión de los conceptos típicos de otras disciplinas. Muitas discussões vêm acontecendo sobre a relevância dos temas abordados em sala de aula. Um tema, em

Trayectoria de los tornillos pediculares lumbares y sacros: Comparación entre el abordaje por linea media versus el abordaje posterolateral tipo wiltse

PubMed Central

Gagliardi, Martín; Guiroy, Alfredo; Molina, Federico Fernández; Fasano, Francisco; Ciancio, Alejandro Morales; Mezzadri, Juan José; Jalón, Pablo

2017-01-01

Resumen Objetivos: El objetivo de este estudio fue comparar, en fusiones lumbosacras cortas, el ángulo de convergencia de los tornillos pediculares entre el abordaje posterolateral tipo Wiltse y el abordaje mediano convencional. Método: Se revisaron en forma retrospectiva los controles en tomografía axial computada (TAC) de 76 tornillos pediculares lumbares y sacros colocados por vía posterior, mediante un abordaje mediano convencional (n: 38) o por vía posterolateral transmuscular tipo Wiltse (n: 38). Se incluyeron fusiones lumbosacras cortas desde L3 a S1, en pacientes adultos, con patología degenerativa. Se excluyeron los tornillos con una brecha ósea >4 mm en cualquier dirección, los casos con instrumentaciones pediculares previas y aquellos con curvas en el plano coronal mayores de 20°. Resultados: Considerando la totalidad de los implantes, el ángulo de convergencia fue de 23,3° (+/- 15,82). La angulación promedio, en el grupo AW, fue de 29,3° (+/- 9,72). En el grupo AC, el grado de convergencia de los implantes fue de 17,2° (+/- 10,58). Esta diferencia fue estadísticamente significativa (P < 0,0001). Para el grupo AW, el grado de convergencia según nivel fue el siguiente: L3: 31,2° (+/- 1,9); L4: 31,4° (+/- 2,76); L5: 31,1° (+/- 5,62); S1: 24,2° (+/- 12,16). El promedio del ángulo del tornillo según nivel para el grupo AC fue: L3: 16° (+/- 7,16); L4: 20,3° (+/- 6,9) L5: 15,9° (+/- 13,38); S1: 15,2° (+/- 14,32). Los implantes del grupo AW tuvieron ángulos significativamente más convergentes que el grupo AC en todos los segmentos explorados. Conclusión: En las fusiones lumbosacras cortas, la utilización del abordaje tipo Wiltse permitió la colocación de tornillos pediculares con más convergencia que en el abordaje mediano convencional. La relevancia clínica de este hecho es desconocida y se requerirían trabajos prospectivos randomizados para determinar la misma. PMID:29142777

Estimaciones de Prevalencia del VIH por Género y Grupo de Riesgo en Tijuana, México: 2006

PubMed Central

Iñiguez-Stevens, Esmeralda; Brouwer, Kimberly C.; Hogg, Robert S.; Patterson, Thomas L.; Lozada, Remedios; Magis-Rodriguez, Carlos; Elder, John P.; Viani, Rolando M.; Strathdee, Steffanie A.

2010-01-01

OBJETIVO Estimar la prevalencia del VIH en adultos de 15-49 años de edad en Tijuana, México - en la población general y en subgrupos de riesgo en el 2006. METODOS Se obtuvieron datos demográficos del censo Mexicano del 2005, y la prevalencia del VIH se obtuvo de la literatura. Se construyó un modelo de prevalencia del VIH para la población general y de acuerdo al género. El análisis de sensibilidad consistió en estimar errores estándar del promedio-ponderado de la prevalencia del VIH y tomar derivados parciales con respecto a cada parámetro. RESULTADOS La prevalencia del VIH es 0.54%(N = 4,347) (Rango: 0.22%–0.86%, (N = 1,750–6,944)). Esto sugiere que 0.85%(Rango: 0.39%–1.31%) de los hombres y 0.22%(Rango: 0.04%–0.40%) de las mujeres podrían ser VIH-positivos. Los hombres que tienen sexo con hombres (HSH), las trabajadoras sexuales usuarias de drogas inyectables (MTS-UDI), MTS-noUDI, mujeres UDI, y los hombres UDI contribuyeron las proporciones más elevadas de personas infectadas por el VIH. CONCLUSIONES El número de adultos VIH-positivos entre subgrupos de riesgo en la población de Tijuana es considerable, marcando la necesidad de enforcar las intervenciones de prevención en sus necesidades específicas. El presente modelo estima que hasta 1 en cada 116 adultos podrían ser VIH-positivos. PMID:19685824

An Evolutionary Perspective on Yeast Mating-Type Switching

PubMed Central

Hanson, Sara J.; Wolfe, Kenneth H.

2017-01-01

Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but structurally distinct processes in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation, MAT locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as Kluyveromyces lactis and the methylotrophic yeasts Ogataea polymorpha and Komagataella phaffii. We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching? PMID:28476860

Brazilian kefir: structure, microbial communities and chemical composition.

PubMed

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-04-01

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml.

Enhanced enzymatic hydrolysis and ethanol production from cashew apple bagasse pretreated with alkaline hydrogen peroxide.

PubMed

da Costa, Jessyca Aline; Marques, José Edvan; Gonçalves, Luciana Rocha Barros; Rocha, Maria Valderez Ponte

2015-03-01

The effect of combinations and ratios between different enzymes has been investigated in order to assess the optimal conditions for hydrolysis of cashew apple bagasse pretreated with alkaline hydrogen peroxide (the solids named CAB-AHP). The separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes were evaluated in the ethanol production. The enzymatic hydrolysis conducted with cellulase complex and β-glucosidase in a ratio of 0.61:0.39, enzyme loading of 30FPU/g(CAB-AHP) and 66CBU/g(CAB-AHP), respectively, using 4% cellulose from CAB-AHP, turned out to be the most effective conditions, with glucose and xylose yields of 511.68 mg/g(CAB-AHP) and 237.8 mg/g(CAB-AHP), respectively. Fermentation of the pure hydrolysate by Kluyveromyces marxianus ATCC 36907 led to an ethanol yield of 61.8kg/ton(CAB), corresponding to 15 g/L ethanol and productivity of 3.75 g/( Lh). The ethanol production obtained for SSF process using K. marxianus ATCC 36907 was 18 g/L corresponding to 80% yield and 74.2kg/ton(CAB). Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative Lipidomic Profiling of S. cerevisiae and Four Other Hemiascomycetous Yeasts

PubMed Central

Hein, Eva-Maria; Hayen, Heiko

2012-01-01

Glycerophospholipids (GP) are the building blocks of cellular membranes and play essential roles in cell compartmentation, membrane fluidity or apoptosis. In addition, GPs are sources for multifunctional second messengers. Whereas the genome and proteome of the most intensively studied eukaryotic model organism, the baker’s yeast (Saccharomyces cerevisiae), are well characterized, the analysis of its lipid composition is still at the beginning. Moreover, different yeast species can be distinguished on the DNA, RNA and protein level, but it is currently unknown if they can also be differentiated by determination of their GP pattern. Therefore, the GP compositions of five different yeast strains, grown under identical environmental conditions, were elucidated using high performance liquid chromatography coupled to negative electrospray ionization-hybrid linear ion trap-Fourier transform ion cyclotron resonance mass spectrometry in single and multistage mode. Using this approach, relative quantification of more than 100 molecular species belonging to nine GP classes was achieved. The comparative lipidomic profiling of Saccharomyces cerevisiae, Saccharomyces bayanus, Kluyveromyces thermotolerans, Pichia angusta, and Yarrowia lipolytica revealed characteristic GP profiles for each strain. However, genetically related yeast strains show similarities in their GP compositions, e.g., Saccharomyces cerevisiae and Saccharomyces bayanus. PMID:24957378

Genome and metabolic engineering in non-conventional yeasts: Current advances and applications.

PubMed

Löbs, Ann-Kathrin; Schwartz, Cory; Wheeldon, Ian

2017-09-01

Microbial production of chemicals and proteins from biomass-derived and waste sugar streams is a rapidly growing area of research and development. While the model yeast Saccharomyces cerevisia e is an excellent host for the conversion of glucose to ethanol, production of other chemicals from alternative substrates often requires extensive strain engineering. To avoid complex and intensive engineering of S. cerevisiae, other yeasts are often selected as hosts for bioprocessing based on their natural capacity to produce a desired product: for example, the efficient production and secretion of proteins, lipids, and primary metabolites that have value as commodity chemicals. Even when using yeasts with beneficial native phenotypes, metabolic engineering to increase yield, titer, and production rate is essential. The non-conventional yeasts Kluyveromyces lactis, K. marxianus, Scheffersomyces stipitis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris have been developed as eukaryotic hosts because of their desirable phenotypes, including thermotolerance, assimilation of diverse carbon sources, and high protein secretion. However, advanced metabolic engineering in these yeasts has been limited. This review outlines the challenges of using non-conventional yeasts for strain and pathway engineering, and discusses the developed solutions to these problems and the resulting applications in industrial biotechnology.

Brazilian kefir: structure, microbial communities and chemical composition

PubMed Central

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-01-01

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml. PMID:24031681

Structure-based nuclear import mechanism of histones H3 and H4 mediated by Kap123

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, Sojin; Yoon, Jungmin; Kim, Hanseong

Kap123, a major karyopherin protein of budding yeast, recognizes the nuclear localization signals (NLSs) of cytoplasmic histones H3 and H4 and translocates them into the nucleus during DNA replication. Mechanistic questions include H3- and H4-NLS redundancy toward Kap123 and the role of the conserved diacetylation of cytoplasmic H4 (K5ac and K12ac) in Kap123-mediated histone nuclear translocation. Here, we report crystal structures of full-length Kluyveromyces lactis Kap123 alone and in complex with H3- and H4-NLSs. Structures reveal the unique feature of Kap123 that possesses two discrete lysine-binding pockets for NLS recognition. Structural comparison illustrates that H3- and H4-NLSs share at leastmore » one of two lysine-binding pockets, suggesting that H3- and H4-NLSs are mutually exclusive. Additionally, acetylation of key lysine residues at NLS, particularly H4-NLS diacetylation, weakens the interaction with Kap123. These data support that cytoplasmic histone H4 diacetylation weakens the Kap123-H4-NLS interaction thereby facilitating histone Kap123-H3-dependent H3:H4/Asf1 complex nuclear translocation.« less

Yeast "make-accumulate-consume" life strategy evolved as a multi-step process that predates the whole genome duplication.

PubMed

Hagman, Arne; Säll, Torbjörn; Compagno, Concetta; Piskur, Jure

2013-01-01

When fruits ripen, microbial communities start a fierce competition for the freely available fruit sugars. Three yeast lineages, including baker's yeast Saccharomyces cerevisiae, have independently developed the metabolic activity to convert simple sugars into ethanol even under fully aerobic conditions. This fermentation capacity, named Crabtree effect, reduces the cell-biomass production but provides in nature a tool to out-compete other microorganisms. Here, we analyzed over forty Saccharomycetaceae yeasts, covering over 200 million years of the evolutionary history, for their carbon metabolism. The experiments were done under strictly controlled and uniform conditions, which has not been done before. We show that the origin of Crabtree effect in Saccharomycetaceae predates the whole genome duplication and became a settled metabolic trait after the split of the S. cerevisiae and Kluyveromyces lineages, and coincided with the origin of modern fruit bearing plants. Our results suggest that ethanol fermentation evolved progressively, involving several successive molecular events that have gradually remodeled the yeast carbon metabolism. While some of the final evolutionary events, like gene duplications of glucose transporters and glycolytic enzymes, have been deduced, the earliest molecular events initiating Crabtree effect are still to be determined.

Carbohydrate and energy-yielding metabolism in non-conventional yeasts.

PubMed

Flores, C L; Rodríguez, C; Petit, T; Gancedo, C

2000-10-01

Sugars are excellent carbon sources for all yeasts. Since a vast amount of information is available on the components of the pathways of sugar utilization in Saccharomyces cerevisiae it has been tacitly assumed that other yeasts use sugars in the same way. However, although the pathways of sugar utilization follow the same theme in all yeasts, important biochemical and genetic variations on it exist. Basically, in most non-conventional yeasts, in contrast to S. cerevisiae, respiration in the presence of oxygen is prominent for the use of sugars. This review provides comparative information on the different steps of the fundamental pathways of sugar utilization in non-conventional yeasts: glycolysis, fermentation, tricarboxylic acid cycle, pentose phosphate pathway and respiration. We consider also gluconeogenesis and, briefly, catabolite repression. We have centered our attention in the genera Kluyveromyces, Candida, Pichia, Yarrowia and Schizosaccharomyces, although occasional reference to other genera is made. The review shows that basic knowledge is missing on many components of these pathways and also that studies on regulation of critical steps are scarce. Information on these points would be important to generate genetically engineered yeast strains for certain industrial uses.

Yeast “Make-Accumulate-Consume” Life Strategy Evolved as a Multi-Step Process That Predates the Whole Genome Duplication

PubMed Central

Hagman, Arne; Säll, Torbjörn; Compagno, Concetta; Piskur, Jure

2013-01-01

When fruits ripen, microbial communities start a fierce competition for the freely available fruit sugars. Three yeast lineages, including baker’s yeast Saccharomyces cerevisiae, have independently developed the metabolic activity to convert simple sugars into ethanol even under fully aerobic conditions. This fermentation capacity, named Crabtree effect, reduces the cell-biomass production but provides in nature a tool to out-compete other microorganisms. Here, we analyzed over forty Saccharomycetaceae yeasts, covering over 200 million years of the evolutionary history, for their carbon metabolism. The experiments were done under strictly controlled and uniform conditions, which has not been done before. We show that the origin of Crabtree effect in Saccharomycetaceae predates the whole genome duplication and became a settled metabolic trait after the split of the S. cerevisiae and Kluyveromyces lineages, and coincided with the origin of modern fruit bearing plants. Our results suggest that ethanol fermentation evolved progressively, involving several successive molecular events that have gradually remodeled the yeast carbon metabolism. While some of the final evolutionary events, like gene duplications of glucose transporters and glycolytic enzymes, have been deduced, the earliest molecular events initiating Crabtree effect are still to be determined. PMID:23869229

Maximization of beta-galactosidase production: a simultaneous investigation of agitation and aeration effects.

PubMed

Alves, Fernanda Germano; Filho, Francisco Maugeri; de Medeiros Burkert, Janaína Fernandes; Kalil, Susana Juliano

2010-03-01

In this work, the agitation and aeration effects in the maximization of the beta-galactosidase production from Kluyveromyces marxianus CCT 7082 were investigated simultaneously, in relation to the volumetric enzyme activity and the productivity, as well as the analysis of the lactose consumption and production of glucose, and galactose of this process. Agitation and aeration effects were studied in a 2 L batch stirred reactor. A central composite design (2(2) trials plus three central points) was carried out. Agitation speed varied from 200 to 500 rpm and aeration rate from 0.5 to 1.5 vvm. It has been shown in this study that the volumetric enzyme production was strongly influenced by mixing conditions, while aeration was shown to be less significant. Linear models for activity and productivity due to agitation and aeration were obtained. The favorable condition was 500 rpm and 1.5 vvm, which lead to the best production of 17 U mL(-1) for enzymatic activity, 1.2 U mL(-1) h(-1) for productivity in 14 h of process, a cellular concentration of 11 mg mL(-1), and a 167.2 h(-1) volumetric oxygen transfer coefficient.

An Effective Big Data Supervised Imbalanced Classification Approach for Ortholog Detection in Related Yeast Species.

PubMed

Galpert, Deborah; Del Río, Sara; Herrera, Francisco; Ancede-Gallardo, Evys; Antunes, Agostinho; Agüero-Chapin, Guillermin

2015-01-01

Orthology detection requires more effective scaling algorithms. In this paper, a set of gene pair features based on similarity measures (alignment scores, sequence length, gene membership to conserved regions, and physicochemical profiles) are combined in a supervised pairwise ortholog detection approach to improve effectiveness considering low ortholog ratios in relation to the possible pairwise comparison between two genomes. In this scenario, big data supervised classifiers managing imbalance between ortholog and nonortholog pair classes allow for an effective scaling solution built from two genomes and extended to other genome pairs. The supervised approach was compared with RBH, RSD, and OMA algorithms by using the following yeast genome pairs: Saccharomyces cerevisiae-Kluyveromyces lactis, Saccharomyces cerevisiae-Candida glabrata, and Saccharomyces cerevisiae-Schizosaccharomyces pombe as benchmark datasets. Because of the large amount of imbalanced data, the building and testing of the supervised model were only possible by using big data supervised classifiers managing imbalance. Evaluation metrics taking low ortholog ratios into account were applied. From the effectiveness perspective, MapReduce Random Oversampling combined with Spark SVM outperformed RBH, RSD, and OMA, probably because of the consideration of gene pair features beyond alignment similarities combined with the advances in big data supervised classification.

Intracellular NADPH Levels Affect the Oligomeric State of the Glucose 6-Phosphate Dehydrogenase

PubMed Central

Tramonti, Angela; Lanini, Claudio; Cialfi, Samantha; De Biase, Daniela; Falcone, Claudio

2012-01-01

In the yeast Kluyveromyces lactis, glucose 6-phosphate dehydrogenase (G6PDH) is detected as two differently migrating forms on native polyacrylamide gels. The pivotal metabolic role of G6PDH in K. lactis led us to investigate the mechanism controlling the two activities in respiratory and fermentative mutant strains. An extensive analysis of these mutants showed that the NAD+(H)/NADP+(H)-dependent cytosolic alcohol (ADH) and aldehyde (ALD) dehydrogenase balance affects the expression of the G6PDH activity pattern. Under fermentative/ethanol growth conditions, the concomitant activation of ADH and ALD activities led to cytosolic accumulation of NADPH, triggering an alteration in the oligomeric state of the G6PDH caused by displacement/release of the structural NADP+ bound to each subunit of the enzyme. The new oligomeric G6PDH form with faster-migrating properties increases as a consequence of intracellular redox unbalance/NADPH accumulation, which inhibits G6PDH activity in vivo. The appearance of a new G6PDH-specific activity band, following incubation of Saccharomyces cerevisiae and human cellular extracts with NADP+, also suggests that a regulatory mechanism of this activity through NADPH accumulation is highly conserved among eukaryotes. PMID:23064253

Results of Mujeres Felices por ser Saludables: a dietary/breast health randomized clinical trial for Latino women.

PubMed

Fitzgibbon, Marian L; Gapstur, Susan M; Knight, Sara J

2004-10-01

Data are limited on the efficacy of health-focused interventions for young, low-acculturated Latino women. Because breast cancer is the most commonly diagnosed cancer and the most common cause of cancer mortality in this population, combined interventions that address both early detection and dietary patterns could help reduce both morbidity and mortality associated with breast cancer in this underserved population. Mujeres Felices por ser Saludables was randomized intervention study designed to assess the efficacy of an 8-month combined dietary and breast health intervention to reduce fat and increase fiber intake as well as to increase the frequency and proficiency of breast self-examination (BSE) and reduce anxiety related to BSE among Latinas. Blocked randomization in blocks of 6 was used to randomize 256 20- to 40-year-old Latinas to the intervention (n = 127) or control group (n = 129). The intervention group attended an 8-month multicomponent education program designed specifically for low-acculturated Latinas. The control group received mailed health education material on a schedule comparable to the intervention. A total of 195 women (76.2%) completed both the baseline and 8-month follow-up interviews. The intervention and control groups were similar on baseline sociodemographic characteristics. At the 8-month follow up, the intervention group reported lower dietary fat (P < .001) and higher fiber intake (p = .06); a higher proportion reported practicing BSE at the recommended interval (p < .001) and showed improved BSE proficiency (p < .001) compared to the control group. BSE-related anxiety was low for both groups at baseline, and no difference in reduction was observed. This project provides a successful model for achieving dietary change and improving breast health behavior in young, low-acculturated Latinas.

Saccharomyces cerevisiae Bat1 and Bat2 Aminotransferases Have Functionally Diverged from the Ancestral-Like Kluyveromyces lactis Orthologous Enzyme

PubMed Central

Colón, Maritrini; Hernández, Fabiola; López, Karla; Quezada, Héctor; González, James; López, Geovani; Aranda, Cristina; González, Alicia

2011-01-01

Background Gene duplication is a key evolutionary mechanism providing material for the generation of genes with new or modified functions. The fate of duplicated gene copies has been amply discussed and several models have been put forward to account for duplicate conservation. The specialization model considers that duplication of a bifunctional ancestral gene could result in the preservation of both copies through subfunctionalization, resulting in the distribution of the two ancestral functions between the gene duplicates. Here we investigate whether the presumed bifunctional character displayed by the single branched chain amino acid aminotransferase present in K. lactis has been distributed in the two paralogous genes present in S. cerevisiae, and whether this conservation has impacted S. cerevisiae metabolism. Principal Findings Our results show that the KlBat1 orthologous BCAT is a bifunctional enzyme, which participates in the biosynthesis and catabolism of branched chain aminoacids (BCAAs). This dual role has been distributed in S. cerevisiae Bat1 and Bat2 paralogous proteins, supporting the specialization model posed to explain the evolution of gene duplications. BAT1 is highly expressed under biosynthetic conditions, while BAT2 expression is highest under catabolic conditions. Bat1 and Bat2 differential relocalization has favored their physiological function, since biosynthetic precursors are generated in the mitochondria (Bat1), while catabolic substrates are accumulated in the cytosol (Bat2). Under respiratory conditions, in the presence of ammonium and BCAAs the bat1Δ bat2Δ double mutant shows impaired growth, indicating that Bat1 and Bat2 could play redundant roles. In K. lactis wild type growth is independent of BCAA degradation, since a Klbat1Δ mutant grows under this condition. Conclusions Our study shows that BAT1 and BAT2 differential expression and subcellular relocalization has resulted in the distribution of the biosynthetic and catabolic roles of the ancestral BCAT in two isozymes improving BCAAs metabolism and constituting an adaptation to facultative metabolism. PMID:21267457

Bifurcación de las soluciones de vientos impulsados por radiación en estrellas Be: formación de líneas

NASA Astrophysics Data System (ADS)

Curé, M.; Rial, D.; Cidale, L.; Venero, R.

Se ha estudiado la topología de la ecuación hidrodinámica no-lineal que describe el perfil de velocidades de vientos impulsados por radiación en estrellas tempranas. Al aplicar este modelo a estrellas Be se encuentra que existen dos tipos De soluciones: la estándar, que describe el viento polar, y una nueva, que describe un viento más denso y lento y que explicaría el disco que se encuentra alrededor de estos objetos. Existe una región de transición en donde ambas soluciones coexisten (bifurcación}). Ambas soluciones satisfacen en esta región las mismas condiciones de borde. Para estas dos soluciones se han obtenido los perfiles de líneas de hidrógeno del visible y del IR, resolviendo el transporte de radiación en el ``comoving frame". Para la solución estándar, se obtienen perfiles con componentes en emisión, mientras que para la nueva solución se obtienen perfiles en absorción. Se comparan cualitativamente los resultados con las observaciones.

Controlled production of camembert-type cheeses: part III role of the ripening microflora on free fatty acid concentrations.

PubMed

Leclercq-Perlat, Marie-Noëlle; Corrieu, Georges; Spinnler, Henry-Eric

2007-05-01

Phenomena generating FFAs, important flavour precursors, are significant in cheese ripening. In Camembert-like cheeses, it was intended to establish the relationships between the dynamics of FFA concentrations changes and the succession of ripening microflora during ripening. Experimental Camembert-type cheeses were prepared in duplicate from pasteurised milk inoculated with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti, and Brevibacterium aurantiacum under aseptic conditions. For each cheese and each cheesy medium, concentrations of FFAs with odd-numbered carbons, except for 9:0 and 13:0, did not change over time. For long-chain FFAs, concentrations varied with the given cheese part (rind or core). K. lactis produced only short or medium-chain FFAs during its growth and had a minor influence on caproic, caprylic, capric, and lauric acids in comparison with G. candidum, the most lipolytic of the strains used here. It generated all short or medium-chain FFAs (4:0-12:0) during its exponential and slowdown growth periods and only long-chain ones (14:0-18:0) during its stationary phase. Pen. camemberti produced more long-chain FFAs (14:0-18:0) during its sporulation. Brev. aurantiacum did not generate any FFAs. The evidence of links between specific FFAs and the growth of a given microorganism is shown.

The ejector-loop fermenter: Description and performance of the apparatus.

PubMed

Moresi, M; Bartolo Gianturco, G; Sebastiani, E

1983-12-01

A novel fermentation unit, the ejector-loop fermenter (ELF), consisting of an outer-loop tower fermenter, a centrifugal pump, a plate-heat exchanger, and a gas-liquid ejector, was designed and constructed. Aeration was achieved by continuously recirculating the fermentation medium through two different nozzle devices instead of using the traditional expensive air compressor. By carrying out a whey fermentation with Kluyveromyces fragilis as the test organism, either in the ELF or in conventional stirred fermenter, it was possible to confirm that the high sheat streses and mixing shock occurring in the ejector nozzle and diffuser sections did not affect microbial growth. Within the range of experimental power consumption per unit volume (-0.1-5 kW/m(3)), the oxygen transfer capability of the ELF per unit power input was found to vary from 1 to 2.5 kg O(2) kW(-1)h(-1). Moreover, it is shown that there is suficient room for improvement in the performance of the ELF unit by care fully designing the aeration device. In fact, at constant volumetric oxygen transfer coefficient, the power consumpotion per unit volume in a 4-mm nozzle was found to be about 40% less than that in a 6-mm nozzle.

Microbial diversity in raw milk and traditional fermented dairy products (Hurood cheese and Jueke) from Inner Mongolia, China.

PubMed

Gao, M L; Hou, H M; Teng, X X; Zhu, Y L; Hao, H S; Zhang, G L

2017-03-08

Hurood cheese (HC) and Jueke (Jk) are 2 traditional fermented dairy products produced from raw milk (RM) in the Inner Mongolia region of China. They have a long history of production and consumption. The microbial compositions of RM, HC, and Jk vary greatly, and are influenced by their geographical origins and unique processing methods. In this study, 2 batches of RM, HC, and Jk samples were collected (April and August 2015) from the Zhenglan Banner, a region located in the southern part of Inner Mongolian belonging to the Xilingol league prefecture. The bacterial and fungal diversities of the samples were determined by 16S rRNA and 18S rRNA gene sequence analysis, respectively. A total of 112 bacterial and 30 fungal sequences were identified, with Firmicutes and Ascomycota being the predominant phyla for bacteria and fungi, respectively. Lactococcus and Lactobacillus were identified as the main bacterial genera, whereas Kluyveromyces was the predominant fungus identified in the 3 dairy products. Different bacterial and fungal compositions were observed in RM, HC, and Jk samples collected at different times. These results suggested that time of production may be an important factor influencing the microbial diversity present in RM, HC, and Jk.

High-Throughput Protein Expression Using a Combination of Ligation-Independent Cloning (LIC) and Infrared Fluorescent Protein (IFP) Detection

PubMed Central

Dortay, Hakan; Akula, Usha Madhuri; Westphal, Christin; Sittig, Marie; Mueller-Roeber, Bernd

2011-01-01

Protein expression in heterologous hosts for functional studies is a cumbersome effort. Here, we report a superior platform for parallel protein expression in vivo and in vitro. The platform combines highly efficient ligation-independent cloning (LIC) with instantaneous detection of expressed proteins through N- or C-terminal fusions to infrared fluorescent protein (IFP). For each open reading frame, only two PCR fragments are generated (with three PCR primers) and inserted by LIC into ten expression vectors suitable for protein expression in microbial hosts, including Escherichia coli, Kluyveromyces lactis, Pichia pastoris, the protozoon Leishmania tarentolae, and an in vitro transcription/translation system. Accumulation of IFP-fusion proteins is detected by infrared imaging of living cells or crude protein extracts directly after SDS-PAGE without additional processing. We successfully employed the LIC-IFP platform for in vivo and in vitro expression of ten plant and fungal proteins, including transcription factors and enzymes. Using the IFP reporter, we additionally established facile methods for the visualisation of protein-protein interactions and the detection of DNA-transcription factor interactions in microtiter and gel-free format. We conclude that IFP represents an excellent reporter for high-throughput protein expression and analysis, which can be easily extended to numerous other expression hosts using the setup reported here. PMID:21541323

Origin Replication Complex Binding, Nucleosome Depletion Patterns, and a Primary Sequence Motif Can Predict Origins of Replication in a Genome with Epigenetic Centromeres

PubMed Central

Tsai, Hung-Ji; Baller, Joshua A.; Liachko, Ivan; Koren, Amnon; Burrack, Laura S.; Hickman, Meleah A.; Thevandavakkam, Mathuravani A.; Rusche, Laura N.

2014-01-01

ABSTRACT Origins of DNA replication are key genetic elements, yet their identification remains elusive in most organisms. In previous work, we found that centromeres contain origins of replication (ORIs) that are determined epigenetically in the pathogenic yeast Candida albicans. In this study, we used origin recognition complex (ORC) binding and nucleosome occupancy patterns in Saccharomyces cerevisiae and Kluyveromyces lactis to train a machine learning algorithm to predict the position of active arm (noncentromeric) origins in the C. albicans genome. The model identified bona fide active origins as determined by the presence of replication intermediates on nondenaturing two-dimensional (2D) gels. Importantly, these origins function at their native chromosomal loci and also as autonomously replicating sequences (ARSs) on a linear plasmid. A “mini-ARS screen” identified at least one and often two ARS regions of ≥100 bp within each bona fide origin. Furthermore, a 15-bp AC-rich consensus motif was associated with the predicted origins and conferred autonomous replicating activity to the mini-ARSs. Thus, while centromeres and the origins associated with them are epigenetic, arm origins are dependent upon critical DNA features, such as a binding site for ORC and a propensity for nucleosome exclusion. PMID:25182328

Comparison of volatile sulphur compound production by cheese-ripening yeasts from methionine and methionine-cysteine mixtures.

PubMed

López Del Castillo-Lozano, M; Delile, A; Spinnler, H E; Bonnarme, P; Landaud, S

2007-07-01

Production of volatile sulphur compounds (VSC) was assessed in culture media supplemented with L-methionine or L-methionine/L-cysteine mixtures, using five cheese-ripening yeasts: Debaryomyces hansenii DH47(8), Kluyveromyces lactis KL640, Geotrichum candidum GC77, Yarrowia lipolytica YL200 and Saccharomyces cerevisiae SC45(3). All five yeasts produced VSC with L-methionine or L-methionine/L-cysteine, but different VSC profiles were found. GC77 and YL200 produced dimethyldisulphide and trace levels of dimethyltrisulphide while DH47(8), KL640 and SC45(3) produced mainly methionol and low levels of methional. S-methylthioacetate was produced by all the yeasts but at different concentrations. DH47(8), KL640 and SC45(3) also produced other minor VSC including 3-methylthiopropyl acetate, ethyl-3-methylthiopropanoate, a thiophenone, and an oxathiane. However, VSC production diminished in a strain-dependent behaviour when L-cysteine was supplemented, even at a low concentration (0.2 g l(-1)). This effect was due mainly to a significant decrease in L-methionine consumption in all the yeasts except YL200. Hydrogen sulphide produced by L-cysteine catabolism did not seem to contribute to VSC generation at the acid pH of yeast cultures. The significance of such results in the cheese-ripening context is discussed.

Characterization and stability of lactobacilli and yeast microbiota in kefir grains.

PubMed

Vardjan, T; Mohar Lorbeg, P; Rogelj, I; Čanžek Majhenič, A

2013-05-01

Characterization and stability of lactobacilli and yeasts from kefir grains using culture-dependent and culture-independent methods were investigated in this study. Culture-dependent analysis, followed by sequencing of 16S ribosomal DNA for bacteria and 26S rRNA gene for yeasts, revealed 3 different species of lactobacilli and yeasts, respectively. The most frequently isolated bacterial species were Lactobacillus kefiranofaciens ssp. kefirgranum, Lb. parakefiri, and Lb. kefiri, whereas yeasts belonged to Kluyveromyces marxianus, Kazachstania exigua, and Rhodosporidium kratochvilovae. This study is the first to report on the presence of R. kratochvilovae in kefir grains. On the other hand, PCR-denaturing gradient gel electrophoresis in the culture-independent method showed that the dominant microorganisms were Lb. kefiranofaciens ssp. kefirgranum, Kl. marxianus and Ka. exigua, but did not reveal bands corresponding to Lb. parakefiri, Lb. kefiri, or R. kratochvilovae. Our results support the necessity of combining more techniques for detailed and reliable study of microbial communities in kefir grains. Another interesting finding confirmed that the detected dominant microbiota of kefir grains is very stable and did not change over experimental time. This finding is important to ensure consistent product quality. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

An Effective Big Data Supervised Imbalanced Classification Approach for Ortholog Detection in Related Yeast Species

PubMed Central

Galpert, Deborah; del Río, Sara; Herrera, Francisco; Ancede-Gallardo, Evys; Antunes, Agostinho; Agüero-Chapin, Guillermin

2015-01-01

Orthology detection requires more effective scaling algorithms. In this paper, a set of gene pair features based on similarity measures (alignment scores, sequence length, gene membership to conserved regions, and physicochemical profiles) are combined in a supervised pairwise ortholog detection approach to improve effectiveness considering low ortholog ratios in relation to the possible pairwise comparison between two genomes. In this scenario, big data supervised classifiers managing imbalance between ortholog and nonortholog pair classes allow for an effective scaling solution built from two genomes and extended to other genome pairs. The supervised approach was compared with RBH, RSD, and OMA algorithms by using the following yeast genome pairs: Saccharomyces cerevisiae-Kluyveromyces lactis, Saccharomyces cerevisiae-Candida glabrata, and Saccharomyces cerevisiae-Schizosaccharomyces pombe as benchmark datasets. Because of the large amount of imbalanced data, the building and testing of the supervised model were only possible by using big data supervised classifiers managing imbalance. Evaluation metrics taking low ortholog ratios into account were applied. From the effectiveness perspective, MapReduce Random Oversampling combined with Spark SVM outperformed RBH, RSD, and OMA, probably because of the consideration of gene pair features beyond alignment similarities combined with the advances in big data supervised classification. PMID:26605337

Utilization of concentrated cheese whey for the production of protein concentrate fuel alcohol and alcoholic beverages

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnamurti, R.

The objective of this investigation was to recover the major components of whey and to develop food applications for their incorporation/conversion into acceptable products of commercial value. Reconstituted dried sweet whey with 36% solids was ultrafiltered to yield a protein concentrate (WPC) and a permeate containing 24% lactose and 3.7% ash. Orange juice fortified up to 2.07% and chocolate milks fortified up to 5.88% total protein levels with WPC containing 45% total protein were acceptable to about 90% of a panel of 24 individuals. Fermentation of demineralized permeate at 30/sup 0/C with Kluyveromyces fragilis NRRL Y 2415 adapted to 24%more » lactose levels, led to 13.7% (v/v) ethanol in the medium at the end of 34 hours. Batch productivity was 3.2 gms. ethanol per liter per hour and conversion efficiency was 84.26% of the theoretical maximum. Alcoholic fermentation of permeate and subsequent distillation produced compounds with desirable aroma characters in such products. This study suggests that there is potential for the production of protein fortified non-alcoholic products and alcoholic beverages of commercial value from whey, thus providing a cost effective solution to the whey utilization problem.« less

Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases

PubMed Central

Dutra Rosolen, Michele; Gennari, Adriano; Volpato, Giandra; Volken de Souza, Claucia Fernanda

2015-01-01

This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C) and Kluyveromyces lactis (at temperatures of 10 and 37°C) β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C), at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry. PMID:26587283

Alpha3, a transposable element that promotes host sexual reproduction.

PubMed

Barsoum, Emad; Martinez, Paula; Aström, Stefan U

2010-01-01

Theoretical models predict that selfish DNA elements require host sex to persist in a population. Therefore, a transposon that induces sex would strongly favor its own spread. We demonstrate that a protein homologous to transposases, called alpha3, was essential for mating type switch in Kluyveromyces lactis. Mutational analysis showed that amino acids conserved among transposases were essential for its function. During switching, sequences in the 5' and 3' flanking regions of the alpha3 gene were joined, forming a DNA circle, showing that alpha3 mobilized from the genome. The sequences encompassing the alpha3 gene circle junctions in the mating type alpha (MATalpha) locus were essential for switching from MATalpha to MATa, suggesting that alpha3 mobilization was a coupled event. Switching also required a DNA-binding protein, Mating type switch 1 (Mts1), whose binding sites in MATalpha were important. Expression of Mts1 was repressed in MATa/MATalpha diploids and by nutrients, limiting switching to haploids in low-nutrient conditions. A hairpin-capped DNA double-strand break (DSB) was observed in the MATa locus in mre11 mutant strains, indicating that mating type switch was induced by MAT-specific DSBs. This study provides empirical evidence for selfish DNA promoting host sexual reproduction by mediating mating type switch.

Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases.

PubMed

Dutra Rosolen, Michele; Gennari, Adriano; Volpato, Giandra; Volken de Souza, Claucia Fernanda

2015-01-01

This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C) and Kluyveromyces lactis (at temperatures of 10 and 37°C) β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C), at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry.

Production of polyunsaturated fatty acids in yeast Saccharomyces cerevisiae and its relation to alkaline pH tolerance.

PubMed

Yazawa, Hisashi; Iwahashi, Hitoshi; Kamisaka, Yasushi; Kimura, Kazuyoshi; Uemura, Hiroshi

2009-03-01

Saccharomyces cerevisiae produces saturated and monounsaturated fatty acids of 16- and 18-carbon atoms and no polyunsaturated fatty acids (PUFAs) with more than two double bonds. To study the biological significance of PUFAs in yeast, we introduced Kluyveromyces lactis Delta12 fatty acid desaturase (KlFAD2) and omega3 fatty acid desaturase (KlFAD3) genes into S. cerevisiae to produce linoleic and alpha-linolenic acids in S. cerevisiae. The strain producing linoleic and alpha-linolenic acids showed an alkaline pH-tolerant phenotype. DNA microarray analyses showed that the transcription of a set of genes whose expressions are under the repression of Rim101p were downregulated in this strain, suggesting that Rim101p, a transcriptional repressor which governs the ion tolerance, was activated. In line with this activation, the strain also showed elevated resistance to Li(+) and Na(+) ions and to zymolyase, a yeast lytic enzyme preparation containing mainly beta-1,3-glucanase, indicating that the cell wall integrity was also strengthened in this strain. Our findings demonstrate a novel influence of PUFA production on transcriptional control that is likely to play an important role in the early stage of alkaline stress response. The Accession No. for microarray data in the Center for Information Biology Gene Expression database is CBX68.

Elucidation of new condition-dependent roles for fructose-1,6-bisphosphatase linked to cofactor balances

PubMed Central

Kilian, Stephanus G.; du Preez, James C.

2017-01-01

The cofactor balances in metabolism is of paramount importance in the design of a metabolic engineering strategy and understanding the regulation of metabolism in general. ATP, NAD+ and NADP+ balances are central players linking the various fluxes in central metabolism as well as biomass formation. NADP+ is especially important in the metabolic engineering of yeasts for xylose fermentation, since NADPH is required by most yeasts in the initial step of xylose utilisation, including the fast-growing Kluyveromyces marxianus. In this simulation study of yeast metabolism, the complex interplay between these cofactors was investigated; in particular, how they may affect the possible roles of fructose-1,6-bisphosphatase, the pentose phosphate pathway, glycerol production and the pyruvate dehydrogenase bypass. Using flux balance analysis, it was found that the potential role of fructose-1,6-bisphosphatase was highly dependent on the cofactor specificity of the oxidative pentose phosphate pathway and on the carbon source. Additionally, the excessive production of ATP under certain conditions might be involved in some of the phenomena observed, which may have been overlooked to date. Based on these findings, a strategy is proposed for the metabolic engineering of a future xylose-fermenting yeast for biofuel production. PMID:28542187

Selection of enhanced antimicrobial activity posing lactic acid bacteria characterised by (GTG)5-PCR fingerprinting.

PubMed

Šalomskienė, Joana; Abraitienė, Asta; Jonkuvienė, Dovilė; Mačionienė, Irena; Repečkienė, Jūratė

2015-07-01

The aim of the study was a detail evaluation of genetic diversity among the lactic acid bacteria (LAB) strains having an advantage of a starter culture in order to select genotypically diverse strains with enhanced antimicrobial effect on some harmfull and pathogenic microorganisms. Antimicrobial activity of LAB was performed by the agar well diffusion method and was examined against the reference strains and foodborne isolates of Bacillus cereus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella Typhimurium. Antifungal activity was tested against the foodborne isolates of Candida parapsilosis, Debaromyces hansenii, Kluyveromyces marxianus, Pichia guilliermondii, Yarowia lipolytica, Aspergillus brasiliensis, Aspergillus versicolor, Cladosporium herbarum, Penicillium chrysogenum and Scopulariopsis brevicaulis. A total 40 LAB strains representing Lactobacillus (23 strains), Lactococcus (13 strains) and Streptococcus spp. (4 strains) were characterised by repetitive sequence based polymerase chain reaction fingerprinting which generated highly discriminatory profiles, confirmed the identity and revealed high genotypic heterogeneity among the strains. Many of tested LAB demonstrated strong antimicrobial activity specialised against one or few indicator strains. Twelve LAB strains were superior in suppressing growth of the whole complex of pathogenic bacteria and fungi. These results demonstrated that separate taxonomic units offered different possibilities of selection for novel LAB strains could be used as starter cultures enhancing food preservation.

Comparison of Yeasts as Hosts for Recombinant Protein Production.

PubMed

Vieira Gomes, Antonio Milton; Souza Carmo, Talita; Silva Carvalho, Lucas; Mendonça Bahia, Frederico; Parachin, Nádia Skorupa

2018-04-29

Recombinant protein production emerged in the early 1980s with the development of genetic engineering tools, which represented a compelling alternative to protein extraction from natural sources. Over the years, a high level of heterologous protein was made possible in a variety of hosts ranging from the bacteria Escherichia coli to mammalian cells. Recombinant protein importance is represented by its market size, which reached $1654 million in 2016 and is expected to reach $2850.5 million by 2022. Among the available hosts, yeasts have been used for producing a great variety of proteins applied to chemicals, fuels, food, and pharmaceuticals, being one of the most used hosts for recombinant production nowadays. Historically, Saccharomyces cerevisiae was the dominant yeast host for heterologous protein production. Lately, other yeasts such as Komagataella sp., Kluyveromyces lactis , and Yarrowia lipolytica have emerged as advantageous hosts. In this review, a comparative analysis is done listing the advantages and disadvantages of using each host regarding the availability of genetic tools, strategies for cultivation in bioreactors, and the main techniques utilized for protein purification. Finally, examples of each host will be discussed regarding the total amount of protein recovered and its bioactivity due to correct folding and glycosylation patterns.

Lactic acid bacteria and yeasts associated with gowé production from sorghum in Bénin.

PubMed

Vieira-Dalodé, G; Jespersen, L; Hounhouigan, J; Moller, P L; Nago, C M; Jakobsen, M

2007-08-01

To identify the dominant micro-organisms involved in the production of gowé, a fermented beverage, and to select the most appropriate species for starter culture development. Samples of sorghum gowé produced twice at three different production sites were taken at different fermentation times. DNA amplification by internal transcribed spacer-polymerase chain reaction of 288 lactic acid bacteria (LAB) isolates and 16S rRNA gene sequencing of selected strains revealed that the dominant LAB responsible for gowé fermentation were Lactobacillus fermentum, Weissella confusa, Lactobacillus mucosae, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella kimchii. DNA from 200 strains of yeasts was amplified and the D1/D2 domain of the 26S rRNA gene was sequenced for selected isolates, revealing that the yeasts species were Kluyveromyces marxianus, Pichia anomala, Candida krusei and Candida tropicalis. Gowé processing is characterized by a mixed fermentation dominated by Lact. fermentum, W. confusa and Ped. acidilactici for the LAB and by K. marxianus, P. anomala and C. krusei for the yeasts. The diversity of the LAB and yeasts identified offers new opportunities for technology upgrading and products development in gowé production. The identified species can be used as possible starter for a controlled fermentation of gowé.

Vicilin-like peptides from Capsicum baccatum L. seeds are α-amylase inhibitors and exhibit antifungal activity against important yeasts in medical mycology.

PubMed

Vieira Bard, Gabriela C; Nascimento, Viviane V; Oliveira, Antônia Elenir A; Rodrigues, Rosana; Da Cunha, Maura; Dias, Germana B; Vasconcelos, Ilka M; Carvalho, Andre O; Gomes, Valdirene M

2014-07-01

The objective of this study was to isolate antimicrobial peptides from Capsicum baccatum seeds and evaluate their antimicrobial activity and inhibitory effects against α-amylase. Initially, proteins from the flour of C. baccatum seeds were extracted in sodium phosphate buffer, pH 5.4, and precipitated with ammonium sulfate at 90% saturation. The D1 and D2 fractions were subjected to antifungal tests against the yeasts Saccharomyces cerevisiae, Candida albicans, Candida tropicalis, and Kluyveromyces marxiannus, and tested against α-amylases from Callosobruchus maculates and human saliva. The D2 fraction presented higher antimicrobial activity and was subjected to further purification and seven new different fractions (H1-H7) were obtained. Peptides in the H4 fraction were sequenced and the N-terminal sequences revealed homology with previously reported storage vicilins from seeds. The H4 fraction exhibited strong antifungal activity and also promoted morphological changes in yeast, including pseudohyphae formation. All fractions, including H4, inhibited mammalian α-amylase activity but only the H4 fraction was able to inhibit C. maculatus α-amylase activity. These results suggest that the fractions isolated from the seeds of C. baccatum can act directly in plant defenses against pathogens and insects. © 2014 Wiley Periodicals, Inc.

Contaminación por mercurio de leche materna de madres lactantes de municipios de Antioquia con explotación minera de oro.

PubMed

Molina, Carlos Federico; Arango, Catalina María; Sepúlveda, Hernán

2018-05-01

Introducción. La leche materna es esencial para el desarrollo del ser humano, pero puede contener sustancias tóxicas provenientes de la contaminación ambiental, especialmente en las áreas mineras.Objetivo. Determinar la prevalencia de la contaminación con mercurio de la leche materna de mujeres lactantes residentes en los municipios con explotación minera de oro.Materiales y métodos. Se hizo un estudio transversal de 150 madres lactantes de cuatro municipios mineros de Antioquia (El Bagre, Segovia, Remedios y Zaragoza), a quienes se les hizo una encuesta sobre factores sociodemográficos, ocupacionales y ambientales relacionados con el mercurio, y se les tomaron muestras de leche materna, de orina y de cabello. Se calculó el promedio de la concentración de mercurio y las prevalencias municipales de contaminación.Resultados. El promedio de la concentración de mercurio en la leche materna fue de 2,5 (± desviación estándar 9,2) μg/L. La prevalencia de muestras de leche materna con niveles altos de mercurio fue de 11,7 %.Conclusión. En este estudio se evidencia un grave problema en las regiones mineras auríferas de Antioquia por el efecto de la contaminación con mercurio en sectores de la población más vulnerable.

Fuentes de variabilidad en el diagnóstico de gastritis atrófica multifocal asociada con la infección por Helicobacter pylori1

PubMed Central

Bravo, Luis Eduardo; Bravo, Juan Carlos; Realpe, José Luis; Zarama, Guillermo; Piazuelo, MarÍa Blanca; Correa, Pelayo

2014-01-01

RESUMEN Introducción El mapeo de las diferentes regiones del estómago y el número de fragmentos de mucosa gástrica disponibles para evaluación histopatológica son fuentes importantes de variación en el momento de clasificar y hacer la gradación de la gastritis crónica. Objetivos Estimar la sensibilidad del número de fragmentos de mucosa gástrica necesarios para establecer los diagnósticos de gastritis atrófica con metaplasia intestinal (MI), displasia y estado de infección por Helicobacter pylori. Además evaluar la variabilidad intra-observador en la clasificación de estas lesiones precursoras del cáncer gástrico. Materiales y métodos En una cohorte de 6 años de seguimiento se evaluaron 1,958 procedimientos de endoscopia realizados por dos gastroenterólogos. En cada procedimiento y de cada participante se obtuvieron 5 biopsias de mucosa gástrica que representaban antro, incisura angularis y cuerpo. Un único patólogo hizo la interpretación histológica de las 5 biopsias y proporcionó un diagnóstico definitivo global que se utilizó como patrón de referencia. Cada fragmento de mucosa gástrica examinado condujo a un diagnóstico individual para cada biopsia que se comparó con el patrón de referencia. La variabilidad intra-observador se evaluó en 127 personas que corresponden a una muestra aleatoria de 20% del total de endoscopias hechas a los 72 meses de seguimiento. Resultados La sensibilidad del diagnóstico de MI y displasia gástrica aumentó de manera significativa con el número de fragmentos de mucosa gástrica evaluados El sitio anatómico de mayor sensibilidad para el diagnóstico de MI y displasia fue la incisura angularis. Para descubrir H. pylori se logró alta sensibilidad con el estudio de un solo fragmento de mucosa gástrica (95.9%) y fue independiente del sitio de obtención de la biopsia. El acuerdo intra-observador para el diagnóstico de gastritis crónica fue 86.1% con valor kappa de 0.79 IC 95% (0.76-0.85). Las

From grape berries to wine: population dynamics of cultivable yeasts associated to "Nero di Troia" autochthonous grape cultivar.

PubMed

Garofalo, Carmela; Tristezza, Mariana; Grieco, Francesco; Spano, Giuseppe; Capozzi, Vittorio

2016-04-01

The aim of this work was to study the biodiversity of yeasts isolated from the autochthonous grape variety called "Uva di Troia", monitoring the natural diversity from the grape berries to wine during a vintage. Grapes were collected in vineyards from two different geographical areas and spontaneous alcoholic fermentations (AFs) were performed. Different restriction profiles of ITS-5.8S rDNA region, corresponding to Saccharomyces cerevisiae, Issatchenkia orientalis, Metschnikowia pulcherrima, Hanseniaspora uvarum, Candida zemplinina, Issatchenkia terricola, Kluyveromyces thermotolerans, Torulaspora delbrueckii, Metschnikowia chrysoperlae, Pichia fermentans, Hanseniaspora opuntiae and Hanseniaspora guilliermondii, were observed. The yeast occurrences varied significantly from both grape berries and grape juices, depending on the sampling location. Furthermore, samples collected at the end of AF revealed the great predominance of Saccharomyces cerevisiae, with a high intraspecific biodiversity. This is the first report on the population dynamics of 'cultivable' microbiota diversity of "Uva di Troia" cultivar from the grape to the corresponding wine ("Nero di Troia"), and more general for Southern Italian oenological productions, allowing us to provide the basis for an improved management of wine yeasts (with both non-Saccharomyces and Saccharomyces) for the production of typical wines with desired unique traits. A certain geographical-dependent variability has been reported, suggesting the need of local based formulation for autochthonous starter cultures, especially in the proportion of the different species/strains in the design of mixed microbial preparations.

Yeast Biomass Production in Brewery's Spent Grains Hemicellulosic Hydrolyzate

NASA Astrophysics Data System (ADS)

Duarte, Luís C.; Carvalheiro, Florbela; Lopes, Sónia; Neves, Ines; Gírio, Francisco M.

Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery's spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h-1, 0.61 g g-1, and 0.56 g 1-1 h-1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids.

Utilization of Cheese Whey Using Synergistic Immobilization of β-Galactosidase and Saccharomyces cerevisiae Cells in Dual Matrices.

PubMed

Kokkiligadda, Anusha; Beniwal, Arun; Saini, Priyanka; Vij, Shilpa

2016-08-01

Whey is a byproduct of the dairy industry, which has prospects of using as a source for production of various valuable compounds. The lactose present in whey is considered as an environmental pollutant and its utilization for enzyme and fuel production, may be effective for whey bioremediation. The dairy yeast Kluyveromyces marxianus have the ability to utilize lactose sharply as the major carbon source for the production of the enzyme. Five strains were tested for the production of the β-galactosidase using whey. The maximum β-galactosidase activity of 1.74 IU/mg dry weight was achieved in whey using K. marxianus MTCC 1389. The biocatalyst was further immobilized on chitosan macroparticles and exhibited excellent functional activity at 35 °C. Almost 89 % lactose hydrolysis was attained for concentrated whey (100 g/L) and retained 89 % catalytic activity after 15 cycles of reuse. Finally, β-galactosidase was immobilized on chitosan and Saccharomyces cerevisiae on calcium alginate, and both were used together for the production of ethanol from concentrated whey. Maximal ethanol titer of 28.9 g/L was achieved during fermentation at 35 °C. The conclusions generated by employing two different matrices will be beneficial for the future modeling using engineered S. cerevisiae in scale-up studies.

A differential medium for the enumeration of the spoilage yeast Zygosaccharomyces bailii in wine.

PubMed

Schuller, D; Côrte-Real, M; Leão, C

2000-11-01

A collection of yeasts, isolated mostly from spoiled wines, was used in order to develop a differential medium for Zygosaccharomyces bailii. The 118 selected strains of 21 species differed in their origin and resistance to preservatives and belonged to the genera Pichia, Torulaspora, Dekkera, Debaryomyces, Saccharomycodes, Issatchenkia, Kluyveromyces, Kloeckera, Lodderomyces, Schizosaccharomyces, Rhodotorula, Saccharomyces, and Zygosaccharomyces. The design of the culture medium was based on the different ability of the various yeast species to grow in a mineral medium with glucose and formic acid (mixed-substrate medium) as the only carbon and energy sources and supplemented with an acid-base indicator. By manipulating the concentration of the acid and the sugar it was possible to select conditions where only Z. bailii strains gave rise to alkalinization, associated with a color change of the medium (positive response). The final composition of the mixed medium was adjusted as a compromise between the percentage of recovery and selectivity for Z. bailii. This was accomplished by the use of pure or mixed cultures of the yeast strains and applying the membrane filtration methodology. The microbiological analysis of two samples of contaminated Vinho Verde showed that the new medium can be considered as a differential medium to distinguish Z. bailii from other contaminating yeasts, having potential application in the microbiological control of wines and probably other beverages and foods.

The secretory pathway: exploring yeast diversity.

PubMed

Delic, Marizela; Valli, Minoska; Graf, Alexandra B; Pfeffer, Martin; Mattanovich, Diethard; Gasser, Brigitte

2013-11-01

Protein secretion is an essential process for living organisms. In eukaryotes, this encompasses numerous steps mediated by several hundred cellular proteins. The core functions of translocation through the endoplasmic reticulum membrane, primary glycosylation, folding and quality control, and vesicle-mediated secretion are similar from yeasts to higher eukaryotes. However, recent research has revealed significant functional differences between yeasts and mammalian cells, and even among diverse yeast species. This review provides a current overview of the canonical protein secretion pathway in the model yeast Saccharomyces cerevisiae, highlighting differences to mammalian cells as well as currently unresolved questions, and provides a genomic comparison of the S. cerevisiae pathway to seven other yeast species where secretion has been investigated due to their attraction as protein production platforms, or for their relevance as pathogens. The analysis of Candida albicans, Candida glabrata, Kluyveromyces lactis, Pichia pastoris, Hansenula polymorpha, Yarrowia lipolytica, and Schizosaccharomyces pombe reveals that many - but not all - secretion steps are more redundant in S. cerevisiae due to duplicated genes, while some processes are even absent in this model yeast. Recent research obviates that even where homologous genes are present, small differences in protein sequence and/or differences in the regulation of gene expression may lead to quite different protein secretion phenotypes. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Identification and Characterization of Oleaginous Yeast Isolated from Kefir and Its Ability to Accumulate Intracellular Fats in Deproteinated Potato Wastewater with Different Carbon Sources

PubMed Central

Kieliszek, Marek; Jermacz, Karolina; Błażejak, Stanisław

2017-01-01

The search for efficient oleaginous microorganisms, which can be an alternative to fossil fuels and biofuels obtained from oilseed crops, has been going on for many years. The suitability of microorganisms in this regard is determined by their ability to biosynthesize lipids with preferred fatty acid profile along with the concurrent utilization of energy-rich industrial waste. In this study, we isolated, characterized, and identified kefir yeast strains using molecular biology techniques. The yeast isolates identified were Candida inconspicua, Debaryomyces hansenii, Kluyveromyces marxianus, Kazachstania unispora, and Zygotorulaspora florentina. We showed that deproteinated potato wastewater, a starch processing industry waste, supplemented with various carbon sources, including lactose and glycerol, is a suitable medium for the growth of yeast, which allows an accumulation of over 20% of lipid substances in its cells. Fatty acid composition primarily depended on the yeast strain and the carbon source used, and, based on our results, most of the strains met the criteria required for the production of biodiesel. In particular, this concerns a significant share of saturated fatty acids, such as C16:0 and C18:0, and unsaturated fatty acids, such as C18:1 and C18:2. The highest efficiency in lipid biosynthesis exceeded 6.3 g L−1. Kazachstania unispora was able to accumulate the high amount of palmitoleic acid. PMID:29098157

Microbiological and chemical properties of kefir manufactured by entrapped microorganisms isolated from kefir grains.

PubMed

Chen, T-H; Wang, S-Y; Chen, K-N; Liu, J-R; Chen, M-J

2009-07-01

In this study, various yeasts (Kluyveromyces marxianus, Saccharomyces turicensis, Pichia fermentans) and lactic acid bacteria (Lactobacillus kefiranofaciens, Lactobacillus kefiri, Leuconostoc mesenteroides) were entrapped in 2 different microspheres using an entrapment ratio for the strains that was based on the distribution ratio of these organisms in kefir grains. The purpose of this study was to develop a new technique to produce kefir using immobilized starter cultures isolated from kefir grains. An increase in cell counts with fermentation cycles was observed for both the lactic acid bacteria (LAB) and yeasts, whereas the cell counts of kefir grains were very stable during cultivation. Scanning electron microscopy showed that the short-chain lactobacilli and lactococci occupied the surface of the LAB microspheres, whereas the long-chain lactobacilli were inside the microspheres. When the yeasts were analyzed, cells at a high density were entrapped in cracks on the surface and within the microspheres, where they were surrounded by the short-chain lactobacilli. The distribution of the LAB and yeast species in kefir produced from grains and microspheres showed that there was no significant difference between the kefirs produced by the 2 methods; moreover, Leu. mesenteroides and K. marxianus were the predominating microflora in both types of kefir. There was no significant difference in the ethanol and exopolysaccharide contents between the 2 kefirs, although the acidity was different.

Chemical and microbiological characterisation of kefir grains.

PubMed

Garrote, G L; Abraham, A G; De Antoni, G L

2001-11-01

Chemical and microbiological composition of four Argentinean kefir grains from different sources as well as characteristics of the corresponding fermented milk were studied. Kefir grains CIDCA AGK1, AGK2 and AGK4 did not show significant differences in their chemical and microbiological composition. In contrast, protein and yeast content of AGK3 was higher than in the other grains. Although grain microflora comprised lactobacilli, lactococcus, acetic acid bacteria and yeast, we found an important difference regarding species. Lactococcus lactis subsp. lactis, Lactobacillus kefir, Lactobacillus plantarum, Acetobacter and Saccharomyces were present in all types of kefir grain. While Leuconostoc mesenteroides was only isolated from grains CIDCA AGK1 and Lactococcus lactis subsp. lactis biovar diacetylactis, Lactobacillus parakefir and Kluyveromyces marxianus were only isolated from CIDCA AGK2 grains. All grains produced acid products with pH between 3.5 and 4.0. The apparent viscosity of AGK1 fermented milk was greater than the product obtained with AGK4. All fermented milks had inhibitory power towards Escherichia coli but AGK1 and AGK2 supernatants were able to halt the bacterial growth for at least 25 h. Grain weight increment in AGK1, AGK2 and AGK3 during growth in milk did not show significant differences. Despite their fermenting activity, AGK4 grains did not increase their weight.

Microbial communities and chemical changes during fermentation of sugary Brazilian kefir.

PubMed

Magalhães, Karina Teixeira; de M Pereira, G V; Dias, Disney Ribeiro; Schwan, Rosane Freitas

2010-07-01

The microorganisms associated with sugary Brazilian kefir beverage were investigated using a combination of culture-dependent and -independent methods. A total of 289 bacteria and 129 yeasts were identified via phenotypic and genotypic methods. Lb. paracasei (23.8%) was the major bacterial isolate identified, followed by Acetobacter lovaniensis (16.31%), Lactobacillus parabuchneri (11.71%), Lactobacillus kefir (10.03%) and Lactococcus lactis (10.03%). Saccharomyces cerevisiae (54.26%) and Kluyveromyces lactis (20.15%) were the most common yeast species isolated. Scanning electron microscopy showed that the microbiota was dominated by lemon-shaped yeast cells growing in close association with Lactobacillus (long and curved). Some lactic acid bacteria detected by sequence analysis of DGGE (denaturing gradient gel electrophoresis) bands were not recovered at any time through fermentation by plating. Conversely, DGGE fingerprints did not reveal bands corresponding to some of the species isolated by culturing methods. The bacteria Acetobacter lovaniensis and the yeast Kazachstania aerobia are described for the first time in sugary kefir. During the 24 h of fermentation, the concentration of lactic acid ranged from 0.2 to 1.80 mg/ml, and that of acetic acid increased from 0.08 to 1.12 mg/ml. The production of ethanol was limited, reaching a final mean value of 1.24 mg/ml.

Novel features of ARS selection in budding yeast Lachancea kluyveri

PubMed Central

2011-01-01

Background The characterization of DNA replication origins in yeast has shed much light on the mechanisms of initiation of DNA replication. However, very little is known about the evolution of origins or the evolution of mechanisms through which origins are recognized by the initiation machinery. This lack of understanding is largely due to the vast evolutionary distances between model organisms in which origins have been examined. Results In this study we have isolated and characterized autonomously replicating sequences (ARSs) in Lachancea kluyveri - a pre-whole genome duplication (WGD) budding yeast. Through a combination of experimental work and rigorous computational analysis, we show that L. kluyveri ARSs require a sequence that is similar but much longer than the ARS Consensus Sequence well defined in Saccharomyces cerevisiae. Moreover, compared with S. cerevisiae and K. lactis, the replication licensing machinery in L. kluyveri seems more tolerant to variations in the ARS sequence composition. It is able to initiate replication from almost all S. cerevisiae ARSs tested and most Kluyveromyces lactis ARSs. In contrast, only about half of the L. kluyveri ARSs function in S. cerevisiae and less than 10% function in K. lactis. Conclusions Our findings demonstrate a replication initiation system with novel features and underscore the functional diversity within the budding yeasts. Furthermore, we have developed new approaches for analyzing biologically functional DNA sequences with ill-defined motifs. PMID:22204614

Novel features of ARS selection in budding yeast Lachancea kluyveri.

PubMed

Liachko, Ivan; Tanaka, Emi; Cox, Katherine; Chung, Shau Chee Claire; Yang, Lu; Seher, Arael; Hallas, Lindsay; Cha, Eugene; Kang, Gina; Pace, Heather; Barrow, Jasmine; Inada, Maki; Tye, Bik-Kwoon; Keich, Uri

2011-12-28

The characterization of DNA replication origins in yeast has shed much light on the mechanisms of initiation of DNA replication. However, very little is known about the evolution of origins or the evolution of mechanisms through which origins are recognized by the initiation machinery. This lack of understanding is largely due to the vast evolutionary distances between model organisms in which origins have been examined. In this study we have isolated and characterized autonomously replicating sequences (ARSs) in Lachancea kluyveri - a pre-whole genome duplication (WGD) budding yeast. Through a combination of experimental work and rigorous computational analysis, we show that L. kluyveri ARSs require a sequence that is similar but much longer than the ARS Consensus Sequence well defined in Saccharomyces cerevisiae. Moreover, compared with S. cerevisiae and K. lactis, the replication licensing machinery in L. kluyveri seems more tolerant to variations in the ARS sequence composition. It is able to initiate replication from almost all S. cerevisiae ARSs tested and most Kluyveromyces lactis ARSs. In contrast, only about half of the L. kluyveri ARSs function in S. cerevisiae and less than 10% function in K. lactis. Our findings demonstrate a replication initiation system with novel features and underscore the functional diversity within the budding yeasts. Furthermore, we have developed new approaches for analyzing biologically functional DNA sequences with ill-defined motifs.

Potential benefits of the application of yeast starters in table olive processing.

PubMed

Arroyo-López, Francisco N; Romero-Gil, Verónica; Bautista-Gallego, Joaquín; Rodríguez-Gómez, Francisco; Jiménez-Díaz, Rufino; García-García, Pedro; Querol, Amparo; Garrido-Fernández, Antonio

2012-01-01

Yeasts play an important role in the food and beverage industry, especially in products such as bread, wine, and beer, among many others. However, their use as a starter in table olive processing has not yet been studied in detail. The candidate yeast strains should be able to dominate fermentation, together with lactic acid bacteria, but should also provide a number of beneficial advantages. Technologically, yeasts should resist low pH and high salt concentrations, produce desirable aromas, improve lactic acid bacteria growth, and inhibit spoilage microorganisms. Nowadays, they are being considered as probiotic agents because many species are able to resist the passage through the gastrointestinal tract and show favorable effects on the host. In this way, yeasts may improve the health of consumers by means of the degradation of non-assimilated compounds (such as phytate complexes), a decrease in cholesterol levels, the production of vitamins and antioxidants, the inhibition of pathogens, an adhesion to intestinal cell line Caco-2, and the maintenance of epithelial barrier integrity. Many yeast species, usually found in table olive processing (Wickerhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens, and Kluyveromyces lactis, among others), have exhibited some of these properties. Thus, the selection of the most appropriate strains to be used as starters in this fermented vegetable, alone or in combination with lactic acid bacteria, is a promising research line to develop in the near future.

Identification of yeasts and evaluation of their distribution in Taiwanese Kefir and Viili starters.

PubMed

Wang, S Y; Chen, H C; Liu, J R; Lin, Y C; Chen, M J

2008-10-01

The objective of the present study was to investigate yeast communities in kefir grains and viili starters in Taiwan through conventional microbiological cultivation and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The DNA sequencing was used as a validity technique to ensure that all isolates within each group belonged to just one species, and to confirm the identified results of PCR-DGGE. Results indicated that a combination of conventional microbiological cultivation with PCR-DGGE and sequencing could successfully identify 4 yeast species from both types of cultures in Taiwan. Kluyveromyces marxianus, Saccharomyces turicensis, and Pichia fermentans were found in Taiwanese kefir grains with a distribution of 76, 22, and 2%, respectively, whereas Klu. marxianus, Saccharomyces unisporus and P. fermentans were identified in viili starters corresponding to 58, 11, and 31% of the total cell counts, respectively. Furthermore, the culture-independent method was applied to identify the yeast species using DGGE. Only 2 yeast species, Klu. marxianus and S. turicensis, were found in kefir grains and 2, Klu. marxianus and P. fermentans, in viili starters. These results suggest that in samples containing multiple species, PCR-DGGE may fail to detect some species. Sequences of yeast isolates reported in this study have been deposited in the GenBank database under accession nos. DQ139802, AF398485, DQ377652, and AY007920.

Potential benefits of the application of yeast starters in table olive processing

PubMed Central

Arroyo-López, Francisco N.; Romero-Gil, Verónica; Bautista-Gallego, Joaquín; Rodríguez-Gómez, Francisco; Jiménez-Díaz, Rufino; García-García, Pedro; Querol, Amparo; Garrido-Fernández, Antonio

2012-01-01

Yeasts play an important role in the food and beverage industry, especially in products such as bread, wine, and beer, among many others. However, their use as a starter in table olive processing has not yet been studied in detail. The candidate yeast strains should be able to dominate fermentation, together with lactic acid bacteria, but should also provide a number of beneficial advantages. Technologically, yeasts should resist low pH and high salt concentrations, produce desirable aromas, improve lactic acid bacteria growth, and inhibit spoilage microorganisms. Nowadays, they are being considered as probiotic agents because many species are able to resist the passage through the gastrointestinal tract and show favorable effects on the host. In this way, yeasts may improve the health of consumers by means of the degradation of non-assimilated compounds (such as phytate complexes), a decrease in cholesterol levels, the production of vitamins and antioxidants, the inhibition of pathogens, an adhesion to intestinal cell line Caco-2, and the maintenance of epithelial barrier integrity. Many yeast species, usually found in table olive processing (Wickerhamomyces anomalus, Saccharomyces cerevisiae, Pichia membranifaciens, and Kluyveromyces lactis, among others), have exhibited some of these properties. Thus, the selection of the most appropriate strains to be used as starters in this fermented vegetable, alone or in combination with lactic acid bacteria, is a promising research line to develop in the near future.

Identification and Characterization of Oleaginous Yeast Isolated from Kefir and Its Ability to Accumulate Intracellular Fats in Deproteinated Potato Wastewater with Different Carbon Sources.

PubMed

Gientka, Iwona; Kieliszek, Marek; Jermacz, Karolina; Błażejak, Stanisław

2017-01-01

The search for efficient oleaginous microorganisms, which can be an alternative to fossil fuels and biofuels obtained from oilseed crops, has been going on for many years. The suitability of microorganisms in this regard is determined by their ability to biosynthesize lipids with preferred fatty acid profile along with the concurrent utilization of energy-rich industrial waste. In this study, we isolated, characterized, and identified kefir yeast strains using molecular biology techniques. The yeast isolates identified were Candida inconspicua , Debaryomyces hansenii , Kluyveromyces marxianus , Kazachstania unispora , and Zygotorulaspora florentina . We showed that deproteinated potato wastewater, a starch processing industry waste, supplemented with various carbon sources, including lactose and glycerol, is a suitable medium for the growth of yeast, which allows an accumulation of over 20% of lipid substances in its cells. Fatty acid composition primarily depended on the yeast strain and the carbon source used, and, based on our results, most of the strains met the criteria required for the production of biodiesel. In particular, this concerns a significant share of saturated fatty acids, such as C16:0 and C18:0, and unsaturated fatty acids, such as C18:1 and C18:2. The highest efficiency in lipid biosynthesis exceeded 6.3 g L -1 . Kazachstania unispora was able to accumulate the high amount of palmitoleic acid.

Yeast communities associated with artisanal mezcal fermentations from Agave salmiana.

PubMed

Verdugo Valdez, A; Segura Garcia, L; Kirchmayr, M; Ramírez Rodríguez, P; González Esquinca, A; Coria, R; Gschaedler Mathis, A

2011-11-01

The aims of this work were to characterize the fermentation process of mezcal from San Luis Potosi, México and identify the yeasts present in the fermentation using molecular culture-dependent methods (RFLP of the 5.8S-ITS and sequencing of the D1/D2 domain) and also by using a culture-independent method (DGGE). The alcoholic fermentations of two separate musts obtained from Agave salmiana were analyzed. Sugar, ethanol and major volatile compounds concentrations were higher in the first fermentation, which shows the importance of having a quality standard for raw materials, particularly in the concentration of fructans, in order to produce fermented Agave salmiana must with similar characteristics. One hundred ninety-two (192) different yeast colonies were identified, from those present on WL agar plates, by RFLP analysis of the ITS1-5.8S- ITS2 from the rRNA gene, with restriction endonucleases, HhaI, HaeIII and HinfI. The identified yeasts were: Saccharomyces cerevisiae, Kluyveromyces marxianus, Pichia kluyveri, Zygosaccharomyces bailii, Clavispora lusitaniae, Torulaspora delbrueckii, Candida ethanolica and Saccharomyces exiguus. These identifications were confirmed by sequencing the D1-D2 region of the 26S rRNA gene. With the PCR-DGGE method, bands corresponding to S. cerevisiae, K. marxianus and T. delbrueckii were clearly detected, confirming the results obtained with classic techniques.

Occurrence of mycotoxins and yeasts and moulds identification in corn silages in tropical climate.

PubMed

Carvalho, B F; Ávila, C L S; Krempser, P M; Batista, L R; Pereira, M N; Schwan, R F

2016-05-01

This study was aimed to identify yeasts and moulds as well as to detect mycotoxin in corn silages in southern Minas Gerais, Brazil. Corn silages from 36 farms were sampled to analyse dry matter, crude protein, ether extract, ash, neutral detergent fibre, nonfibre carbohydrates and mycotoxins contents, yeasts and moulds population, pH and temperature values. The mycotoxins found in high frequency were aflatoxin in 77·7% of analysed samples, ochratoxin (33·3%) and zearalenone (22·2%). There was no significant correlation between the mycotoxin concentration and the presence of moulds. The pH was negatively correlated with ochratoxin concentration. Aspergillus fumigatus was identified in all silages that presented growth of moulds. Ten different yeast species were identified using the culture-dependent method: Candida diversa, Candida ethanolica, Candida rugosa, Issatchenkia orientalis, Kluyveromyces marxianus, Pichia manshurica, Pichia membranifaciens, Saccharomyces cerevisiae, Trichosporon asahii and Trichosporon japonicum. Another six different yeast species were identified using the culture-independent method. A high mycotoxin contamination rate (91·6% of the analysed silages) was observed. The results indicated that conventional culturing and PCR-DGGE should be combined to optimally describe the microbiota associated with corn silage. This study provides information about the corn silage fermentation dynamics and our findings are relevant to optimization of this silage fermentation. © 2016 The Society for Applied Microbiology.

Modeling of an integrated fermentation/membrane extraction process for the production of 2-phenylethanol and 2-phenylethylacetate.

PubMed

Adler, Philipp; Hugen, Thorsten; Wiewiora, Marzena; Kunz, Benno

2011-03-07

An unstructured model for an integrated fermentation/membrane extraction process for the production of the aroma compounds 2-phenylethanol and 2-phenylethylacetate by Kluyveromyces marxianus CBS 600 was developed. The extent to which this model, based only on data from the conventional fermentation and separation processes, provided an estimation of the integrated process was evaluated. The effect of product inhibition on specific growth rate and on biomass yield by both aroma compounds was approximated by multivariate regression. Simulations of the respective submodels for fermentation and the separation process matched well with experimental results. With respect to the in situ product removal (ISPR) process, the effect of reduced product inhibition due to product removal on specific growth rate and biomass yield was predicted adequately by the model simulations. Overall product yields were increased considerably in this process (4.0 g/L 2-PE+2-PEA vs. 1.4 g/L in conventional fermentation) and were even higher than predicted by the model. To describe the effect of product concentration on product formation itself, the model was extended using results from the conventional and the ISPR process, thus agreement between model and experimental data improved notably. Therefore, this model can be a useful tool for the development and optimization of an efficient integrated bioprocess. Copyright © 2010 Elsevier Inc. All rights reserved.

Lachancea thermotolerans and Saccharomyces cerevisiae in simultaneous and sequential co-fermentation: a strategy to enhance acidity and improve the overall quality of wine.

PubMed

Gobbi, Mirko; Comitini, Francesca; Domizio, Paola; Romani, Cristina; Lencioni, Livio; Mannazzu, Ilaria; Ciani, Maurizio

2013-04-01

In the last few years there is an increasing interest on the use of mixed fermentation of Saccharomyces and non-Saccharomyces wine yeasts for inoculation of wine fermentations to enhance the quality and improve complexity of wines. In the present work Lachancea (Kluyveromyces) thermotolerans and Saccharomyces cerevisiae were evaluated in simultaneous and sequential fermentation with the aim to enhance acidity and improve the quality of wine. In this specific pairing of yeast strains in mixed fermentations (S. cerevisiae EC1118 and L. thermotolerans 101), this non-Saccharomyces yeast showed a high level of competitiveness. Nevertheless the S. cerevisiae strain dominated the fermentation over the spontaneous S. cerevisiae strains also under the industrial fermentation conditions. The different condition tested (modalities of inoculum, temperature of fermentation, different grape juice) influenced the specific interactions and the fermentation behaviour of the co-culture of S. cerevisiae and L. thermotolerans. However, some metabolic behaviours such as pH reduction and enhancement of 2-phenylethanol and glycerol, were shown here under all of the conditions tested. The specific chemical profiles of these wines were confirmed by the sensory analysis test, which expressed these results at the tasting level as significant increases in the spicy notes and in terms of total acidity increases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Autoselection of cytoplasmic yeast virus like elements encoding toxin/antitoxin systems involves a nuclear barrier for immunity gene expression.

PubMed

Kast, Alene; Voges, Raphael; Schroth, Michael; Schaffrath, Raffael; Klassen, Roland; Meinhardt, Friedhelm

2015-05-01

Cytoplasmic virus like elements (VLEs) from Kluyveromyces lactis (Kl), Pichia acaciae (Pa) and Debaryomyces robertsiae (Dr) are extremely A/T-rich (>75%) and encode toxic anticodon nucleases (ACNases) along with specific immunity proteins. Here we show that nuclear, not cytoplasmic expression of either immunity gene (PaORF4, KlORF3 or DrORF5) results in transcript fragmentation and is insufficient to establish immunity to the cognate ACNase. Since rapid amplification of 3' ends (RACE) as well as linker ligation of immunity transcripts expressed in the nucleus revealed polyadenylation to occur along with fragmentation, ORF-internal poly(A) site cleavage due to the high A/T content is likely to prevent functional expression of the immunity genes. Consistently, lowering the A/T content of PaORF4 to 55% and KlORF3 to 46% by gene synthesis entirely prevented transcript cleavage and permitted functional nuclear expression leading to full immunity against the respective ACNase toxin. Consistent with a specific adaptation of the immunity proteins to the cognate ACNases, cross-immunity to non-cognate ACNases is neither conferred by PaOrf4 nor KlOrf3. Thus, the high A/T content of cytoplasmic VLEs minimizes the potential of functional nuclear recruitment of VLE encoded genes, in particular those involved in autoselection of the VLEs via a toxin/antitoxin principle.

Changes in volatile profile of soybean residue (okara) upon solid-state fermentation by yeasts.

PubMed

Vong, Weng Chan; Liu, Shao-Quan

2017-01-01

Soybean residue (okara), a by-product of soymilk, is produced in large volumes by the soy food industry and is often discarded due to its undesirable flavour. As it contains a considerable amount of protein and fats, biotransformation of okara to improve its flavour presents an opportunity for alternative utilisation. This paper evaluated 10 yeasts in the solid-state fermentation of okara based on their volatile profiles as analysed with HS-SPME GC-MS/FID. Four 'dairy yeasts' (Geotrichum candidum, Yarrowia lipolytica, Debaryomyces hansenii and Kluyveromyces lactis) and six 'wine yeasts' (Saccharomyces cerevisiae, Lachancea thermotolerans, Metschnikowia pulcherrima, Pichia kluyveri, Torulaspora delbrueckii, and Williopsis saturnus) were studied. The main off-odourants in okara, hexanal and trans-2-hexenal, significantly decreased after fermentation due to their bioconversion into methyl ketones and/or esters. The okara fermented by dairy yeasts contained greater proportions of methyl ketones, while that by wine yeasts contained more ethyl and acetyl esters. Notably, the okara fermented by W. saturnus contained 13 esters and the total GC-FID peak area of esters was about 380 times that in fresh okara, leading to a perceptible fruity note. Okara can be exploited as an inexpensive substrate for bioflavour extraction and/or a more pleasant food ingredient via yeast fermentation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Isolation, Identification and Characterization of Yeasts from Fermented Goat Milk of the Yaghnob Valley in Tajikistan

PubMed Central

Qvirist, Linnea A.; De Filippo, Carlotta; Strati, Francesco; Stefanini, Irene; Sordo, Maddalena; Andlid, Thomas; Felis, Giovanna E.; Mattarelli, Paola; Cavalieri, Duccio

2016-01-01

The geographically isolated region of the Yaghnob Valley, Tajikistan, has allowed its inhabitants to maintain a unique culture and lifestyle. Their fermented goat milk constitutes one of the staple foods for the Yaghnob population, and is produced by backslopping, i.e., using the previous fermentation batch to inoculate the new one. This study addresses the yeast composition of the fermented milk, assessing genotypic, and phenotypic properties. The 52 isolates included in this study revealed small species diversity, belonging to Kluyveromyces marxianus, Pichia fermentans, Saccharomyces cerevisiae, and one Kazachstania unispora. The K. marxianus strains showed two different genotypes, one of which never described previously. The two genetically different groups also differed significantly in several phenotypic characteristics, such as tolerance toward high temperatures, low pH, and presence of acid. Microsatellite analysis of the S. cerevisiae strains from this study, compared to 350 previously described strains, attributed the Yaghnobi S. cerevisiae to two different ancestry origins, both distinct from the wine and beer strains, and similar to strains isolated from human and insects feces, suggesting a peculiar origin of these strains, and the existence of a gut reservoir for S. cerevisiae. Our work constitutes a foundation for strain selection for future applications as starter cultures in food fermentations. This work is the first ever on yeast diversity from fermented milk of the previously unexplored area of the Yaghnob Valley. PMID:27857705

Selection of non-Saccharomyces yeast strains for reducing alcohol levels in wine by sugar respiration.

PubMed

Quirós, Manuel; Rojas, Virginia; Gonzalez, Ramon; Morales, Pilar

2014-07-02

Respiration of sugars by non-Saccharomyces yeasts has been recently proposed for lowering alcohol levels in wine. Development of industrial fermentation processes based on such an approach requires, amongst other steps, the identification of yeast strains which are able to grow and respire under the relatively harsh conditions found in grape must. This work describes the characterization of a collection of non-Saccharomyces yeast strains in order to identify candidate yeast strains for this specific application. It involved the estimation of respiratory quotient (RQ) values under aerated conditions, at low pH and high sugar concentrations, calculation of yields of ethanol and other relevant metabolites, and characterization of growth responses to the main stress factors found during the first stages of alcoholic fermentation. Physiological features of some strains of Metschnikowia pulcherrima or two species of Kluyveromyces, suggest they are suitable for lowering ethanol yields by respiration. The unsuitability of Saccharomyces cerevisiae strains for this purpose was not due to ethanol yields (under aerated conditions they are low enough for a significant reduction in final ethanol content), but to the high acetic acid yields under these growth conditions. According to results from controlled aeration fermentations with one strain of M. pulcherrima, design of an aeration regime allowing for lowering ethanol yields though preserving grape must components from excessive oxidation, would be conceivable. Copyright © 2014. Published by Elsevier B.V.

Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture.

PubMed

Øverland, Margareth; Skrede, Anders

2017-02-01

The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation. Studies have shown that yeasts such as Saccharomyces cerevisiae, Candida utilis and Kluyveromyces marxianus have favourable amino acid composition and excellent properties as protein sources in diets for fish, including carnivorous species such as Atlantic salmon and rainbow trout. Suitable downstream processing of the biomass to disrupt cell walls is required to secure high nutrient digestibility. A number of studies have shown various immunological and health benefits from feeding fish low levels of yeast and yeast-derived cell wall fractions. This review summarises current literature on the potential of yeast from lignocellulosic biomass as an alternative protein source for the aquaculture industry. It is concluded that further research and development within yeast production can be important to secure the future sustainability and economic viability of intensive aquaculture. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Microbiological, biochemical, and functional aspects of sugary kefir fermentation - A review.

PubMed

Fiorda, Fernanda Assumpção; de Melo Pereira, Gilberto Vinicius; Thomaz-Soccol, Vanete; Rakshit, Sudip Kumar; Pagnoncelli, Maria Giovana Binder; Vandenberghe, Luciana Porto de Souza; Soccol, Carlos Ricardo

2017-09-01

Sugary kefir beverage is produce by fermenting raw sugar solution with kefir grains, the latter consisting of polysaccharide and microorganisms. This beverage, with great consumption in countries such as USA, Japan, France, and Brazil, represents a promising market to functional cultured drinks. This paper reviews the microbial diversity and interaction, kinetics, safety, and bioactivities of sugary kefir fermentation. The literature reviewed here demonstrates that sugary kefir possesses a similar microbial association relative to traditional milk kefir fermentation, especially among lactic acid bacteria and yeast species, such as Lactobacillus, Leuconostoc, Kluyveromyces, Pichia, and Saccharomyces. However, a selective pressure at species level is generally observed, as, for example, the stimulation of Saccharomyces species metabolism, leading to a high content of alcohol in the final product. This also seems to stimulate the growth of acetic acid bacteria that benefit of increased ethanol production to acetic acid metabolism. Existing reports have suggested important bioactivities associated with sugary kefir beverage consumption, such as antimicrobial, antiedematogenic, anti-inflammatory, antioxidant, cicatrizing, and healing activities. Other alternative non-dairy substrates, such as fruits, vegetables, and molasses, have also been tested for adaptation of kefir grains and production of functional beverages with distinct sensory characteristics. This diversification is of crucial importance for the production of new probiotic products to provide people with special needs (lactose intolerance) and vegan consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

The evaluation of kefir pure culture starter: Liquid-core capsule entrapping microorganisms isolated from kefir grains.

PubMed

Wang, Liang; Zhong, Hao; Liu, Keying; Guo, Aizhen; Qi, Xianghui; Cai, Meihong

2016-10-01

The main purpose of this study was to develop a pure culture starter for producing kefir. In order to accomplish starter recycling, yeasts (Kluyveromyces marxianus strain, Pichia kudriavzevii clone), lactic acid bacteria (Lactobacillus kefiri strain F4Aa, Lactobacillus kefiri strain NM131-7, Lactobacillus kefiri strain NM132-3, Lactobacillus kefiri strain NM180-3, respectively), and acetic acid bacteria (Acetobacter lovaniensis strain) were entrapped in liquid core capsules based on the distribution ratio in kefir grains. The microbiological, antimicrobial, and chemical properties of kefir made with capsules (M) and kefir grains (K) were measured and compared. According to the results of plate counts in different selective medium, the number of yeasts and bacteria in the liquid core capsules gradually increased and stabilized after eight fermentation cycles. The results of gas chromatography-mass spectrometry showed that almost all the aroma components existed in the two type of kefir, except the ethyl lactate. There was no significant difference in alcohol content, protein content, and fat content, except the acidity and sugar content. Water holding capacity of kefir K was higher than kefir M. There were 14 same free amino acids in kefir M and kefir K, and the content of most free amino acids was similar. In antimicrobial test, there was no significant difference in both kefirs. © The Author(s) 2016.

Growth, ethanol production, and inulinase activity on various inulin substrates by mutant kluyveromyces marxianus strains NRRL Y-50798 and NRRL Y-50799

USDA-ARS?s Scientific Manuscript database

Economically important plants contain large amounts of inulin. Disposal of waste resulting from their processing presents environmental issues. Finding microorganisms capable of converting inulin waste to biofuel and valuable co-products in a biorefinery at the processing site would have significant...

Nucleotide sequence of the COX1 gene in Kluyveromyces lactis mitochondrial DNA: evidence for recent horizontal transfer of a group II intron.

PubMed

Hardy, C M; Clark-Walker, G D

1991-07-01

The cytochrome oxidase subunit 1 gene (COX1) in K. lactis K8 mtDNA spans 8,826 bp and contains five exons (termed E1-E5) totalling 1,602 bp that show 88% nucleotide base matching and 91% amino acid homology to the equivalent gene in S. cerevisiae. The four introns (termed K1 cox1.1-1.4) contain open reading frames encoding proteins of 786, 333, 319 and 395 amino acids respectively that potentially encode maturase enzymes. The first intron belongs to group II whereas the remaining three are group I type B. Introns K1 cox1.1, 1.3, and 1.4 are found at identical locations to introns Sc cox1.2, 1.5 a, and 1.5 b respectively from S. cerevisiae. Horizontal transfer of an intron between recent progenitors of K. lactis and S. cerevisiae is suggested by the observation that K1 cox1.1 and Sc cox1.2 show 96% base matching. Sequence comparisons between K1 cox1.3/Sc cox1.5 a and K1 cox1.4/Sc cox1.5 b suggest that these introns are likely to have been present in the ancestral COX1 gene of these yeasts. Intron K1 cox1.2 is not found in S. cerevisiae and appears at an unique location in K. lactis. A feature of the DNA sequences of the group I introns K1 cox1.2, 1.3, and 1.4 is the presence of 11 GC-rich clusters inserted into both coding and noncoding regions. Immediately downstream of the COX1 gene is the ATPase subunit 8 gene (A8) that shows 82.6% base matching to its counterpart in S. cerevisiae mtDNA.

A protein secretion system linked to bacteroidete gliding motility and pathogenesis

PubMed Central

Sato, Keiko; Naito, Mariko; Yukitake, Hideharu; Hirakawa, Hideki; Shoji, Mikio; McBride, Mark J.; Rhodes, Ryan G.; Nakayama, Koji

2009-01-01

Porphyromonas gingivalis secretes strong proteases called gingipains that are implicated in periodontal pathogenesis. Protein secretion systems common to other Gram-negative bacteria are lacking in P. gingivalis, but several proteins, including PorT, have been linked to gingipain secretion. Comparative genome analysis and genetic experiments revealed 11 additional proteins involved in gingipain secretion. Six of these (PorK, PorL, PorM, PorN, PorW, and Sov) were similar in sequence to Flavobacterium johnsoniae gliding motility proteins, and two others (PorX and PorY) were putative two-component system regulatory proteins. Real-time RT-PCR analysis revealed that porK, porL, porM, porN, porP, porT, and sov were down-regulated in P. gingivalis porX and porY mutants. Disruption of the F. johnsoniae porT ortholog resulted in defects in motility, chitinase secretion, and translocation of a gliding motility protein, SprB adhesin, to the cell surface, providing a link between a unique protein translocation system and a motility apparatus in members of the Bacteroidetes phylum. PMID:19966289

Differential Regulation of Duplicate Light-Dependent Protochlorophyllide Oxidoreductases in the Diatom Phaeodactylum tricornutum

PubMed Central

Hunsperger, Heather M.; Cattolico, Rose Ann

2016-01-01

Background Diatoms (Bacilliariophyceae) encode two light-dependent protochlorophyllide oxidoreductases (POR1 and POR2) that catalyze the penultimate step of chlorophyll biosynthesis in the light. Algae live in dynamic environments whose changing light levels induce photoacclimative metabolic shifts, including altered cellular chlorophyll levels. We hypothesized that the two POR proteins may be differentially adaptive under varying light conditions. Using the diatom Phaeodactylum tricornutum as a test system, differences in POR protein abundance and por gene expression were examined when this organism was grown on an alternating light:dark cycles at different irradiances; exposed to continuous light; and challenged by a significant decrease in light availability. Results For cultures maintained on a 12h light: 12h dark photoperiod at 200μE m−2 s−1 (200L/D), both por genes were up-regulated during the light and down-regulated in the dark, though por1 transcript abundance rose and fell earlier than that of por2. Little concordance occurred between por1 mRNA and POR1 protein abundance. In contrast, por2 mRNA and POR2 protein abundances followed similar diurnal patterns. When 200L/D P. tricornutum cultures were transferred to continuous light (200L/L), the diurnal regulatory pattern of por1 mRNA abundance but not of por2 was disrupted, and POR1 but not POR2 protein abundance dropped steeply. Under 1200μE m−2 s−1 (1200L/D), both por1 mRNA and POR1 protein abundance displayed diurnal oscillations. A compromised diel por2 mRNA response under 1200L/D did not impact the oscillation in POR2 abundance. When cells grown at 1200L/D were then shifted to 50μE m−2 s−1 (50L/D), por1 and por2 mRNA levels decreased swiftly but briefly upon light reduction. Thereafter, POR1 but not POR2 protein levels rose significantly in response to this light stepdown. Conclusion Given the sensitivity of diatom por1/POR1 to real-time light cues and adherence of por2/POR2 regulation to

Cloning and characterization of an inulinase gene from the marine yeast Candida membranifaciens subsp. flavinogenie W14-3 and its expression in Saccharomyces sp. W0 for ethanol production.

PubMed

Zhang, Lin-Lin; Tan, Mei-Juan; Liu, Guang-Lei; Chi, Zhe; Wang, Guang-Yuan; Chi, Zhen-Ming

2015-04-01

The INU1 gene encoding an exo-inulinase from the marine-derived yeast Candida membranifaciens subsp. flavinogenie W14-3 was cloned and characterized. It had an open reading frame of 1,536 bp long encoding an inulinase. The coding region of it was not interrupted by any intron. The cloned gene encoded 512 amino acid residues of a protein with a putative signal peptide of 23 amino acids and a calculated molecular mass of 57.8 kDa. The protein sequence deduced from the inulinase gene contained the inulinase consensus sequences (WMNDPNGL), (RDP), ECP FS and Q. The protein also had six conserved putative N-glycosylation sites. The deduced inulinase from the yeast strain W14-3 was found to be closely related to that from Candida kutaonensis sp. nov. KRF1, Kluyveromyces marxianus, and Cryptococcus aureus G7a. The inulinase gene with its signal peptide encoding sequence was subcloned into the pMIRSC11 expression vector and expressed in Saccharomyces sp. W0. The recombinant yeast strain W14-3-INU-112 obtained could produce 16.8 U/ml of inulinase activity and 12.5 % (v/v) ethanol from 250 g/l of inulin within 168 h. The monosaccharides were detected after the hydrolysis of inulin with the crude inulinase (the yeast culture). All the results indicated that the cloned gene and the recombinant yeast strain W14-3-INU-112 had potential applications in biotechnology.

The composition of Camembert cheese-ripening cultures modulates both mycelial growth and appearance.

PubMed

Lessard, Marie-Hélène; Bélanger, Gaétan; St-Gelais, Daniel; Labrie, Steve

2012-03-01

The fungal microbiota of bloomy-rind cheeses, such as Camembert, forms a complex ecosystem that has not been well studied, and its monitoring during the ripening period remains a challenge. One limitation of enumerating yeasts and molds on traditional agar media is that hyphae are multicellular structures, and colonies on a petri dish rarely develop from single cells. In addition, fungi tend to rapidly invade agar surfaces, covering small yeast colonies and resulting in an underestimation of their number. In this study, we developed a real-time quantitative PCR (qPCR) method using TaqMan probes to quantify a mixed fungal community containing the most common dairy yeasts and molds: Penicillium camemberti, Geotrichum candidum, Debaryomyces hansenii, and Kluyveromyces lactis on soft-cheese model curds (SCMC). The qPCR method was optimized and validated on pure cultures and used to evaluate the growth dynamics of a ripening culture containing P. camemberti, G. candidum, and K. lactis on the surface of the SCMC during a 31-day ripening period. The results showed that P. camemberti and G. candidum quickly dominated the ecosystem, while K. lactis remained less abundant. When added to this ecosystem, D. hansenii completely inhibited the growth of K. lactis in addition to reducing the growth of the other fungi. This result was confirmed by the decrease in the mycelium biomass on SCMC. This study compares culture-dependent and qPCR methods to successfully quantify complex fungal microbiota on a model curd simulating Camembert-type cheese.

Isolation and identification of yeast flora from genital tract in healthy female camels (Camelus dromedarius).

PubMed

Shokri, Hojjatollah; Khosravi, Alireza; Sharifzadeh, Aghil; Tootian, Zahra

2010-07-29

Yeasts are commensal organisms found in the skin, genital and gastrointestinal tracts, and other mucosal sites in mammalians. The purposes of this study were to identify yeast flora and to determine the number of colony forming units (CFUs) in genital tract of healthy female dromedary camels, establishing their connection in both mated and unmated conditions. The samples were taken from different parts of genital tract including vestibule, vagina, cervix, uterine body, and uterine horns of 50 camels using sterilized cotton swabs. They were cultured onto Sabouraud glucose agar containing chloramphenicol and incubated at 30 degrees C for 7-10 days. A total of 454 yeast colonies were obtained from genital tract. Yeast isolates belonged to 8 genera: Candida (73.1%), Trichosporon (10.1%), Geotrichum (7.5%), Kluyveromyces (3.5%), Rhodotorula (2.4%), Aureobasidium (1.4%), Cryptococcus (1.1%) and Prototheca (0.8%). Among different Candida species, C. zeylanoides was the most common isolated species, representing significant difference with other Candida species (P<0.05). The mean number of yeasts found in the vestibule (46%) was significantly higher than the results obtained from other parts (P<0.05). In addition, the mean value of CFUs from unmated females (71.1%) was significantly higher than mated females (P<0.05). The results showed that C. zeylanoides was a common component of healthy camel females' genital mycoflora and the number of yeasts varied between mated and unmated females. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Comparative Genomics Reveals Chd1 as a Determinant of Nucleosome Spacing in Vivo.

PubMed

Hughes, Amanda L; Rando, Oliver J

2015-07-14

Packaging of genomic DNA into nucleosomes is nearly universally conserved in eukaryotes, and many features of the nucleosome landscape are quite conserved. Nonetheless, quantitative aspects of nucleosome packaging differ between species because, for example, the average length of linker DNA between nucleosomes can differ significantly even between closely related species. We recently showed that the difference in nucleosome spacing between two Hemiascomycete species-Saccharomyces cerevisiae and Kluyveromyces lactis-is established by trans-acting factors rather than being encoded in cis in the DNA sequence. Here, we generated several S. cerevisiae strains in which endogenous copies of candidate nucleosome spacing factors are deleted and replaced with the orthologous factors from K. lactis. We find no change in nucleosome spacing in such strains in which H1 or Isw1 complexes are swapped. In contrast, the K. lactis gene encoding the ATP-dependent remodeler Chd1 was found to direct longer internucleosomal spacing in S. cerevisiae, establishing that this remodeler is partially responsible for the relatively long internucleosomal spacing observed in K. lactis. By analyzing several chimeric proteins, we find that sequence differences that contribute to the spacing activity of this remodeler are dispersed throughout the coding sequence, but that the strongest spacing effect is linked to the understudied N-terminal end of Chd1. Taken together, our data find a role for sequence evolution of a chromatin remodeler in establishing quantitative aspects of the chromatin landscape in a species-specific manner. Copyright © 2015 Hughes and Rando.

Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment

PubMed Central

Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta

2015-01-01

Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality. PMID:26341209

Evaluation of hardboard manufacturing process wastewater as a feedstream for ethanol production.

PubMed

Groves, Stephanie; Liu, Jifei; Shonnard, David; Bagley, Susan

2013-07-01

Waste streams from the wood processing industry can serve as feedstream for ethanol production from biomass residues. Hardboard manufacturing process wastewater (HPW) was evaluated on the basis of monomeric sugar recovery and fermentability as a novel feedstream for ethanol production. Dilute acid hydrolysis, coupled with concentration of the wastewater resulted in a hydrolysate with 66 g/l total fermentable sugars. As xylose accounted for 53 % of the total sugars, native xylose-fermenting yeasts were evaluated for their ability to produce ethanol from the hydrolysate. The strains selected were, in decreasing order by ethanol yields from xylose (Y p/s, based on consumed sugars), Scheffersomyces stipitis ATCC 58785 (CBS 6054), Pachysolen tannophilus ATCC 60393, and Kluyveromyces marxianus ATCC 46537. The yeasts were compared on the basis of substrate utilization and ethanol yield during fermentations of the hydrolysate, measured using an HPLC. S. stipitis, P. tannophilus, and K. marxianus produced 0.34, 0.31, and 0.36 g/g, respectively. The yeasts were able to utilize between 58 and 75 % of the available substrate. S. stipitis outperformed the other yeast during the fermentation of the hydrolysate; consuming the highest concentration of available substrate and producing the highest ethanol concentration in 72 h. Due to its high sugar content and low inhibitor levels after hydrolysis, it was concluded that HPW is a suitable feedstream for ethanol production by S. stipitis.

Inhibition of Listeria monocytogenes by Food-Borne Yeasts†

PubMed Central

Goerges, Stefanie; Aigner, Ulrike; Silakowski, Barbara; Scherer, Siegfried

2006-01-01

Many bacteria are known to inhibit food pathogens, such as Listeria monocytogenes, by secreting a variety of bactericidal and bacteriostatic substances. In sharp contrast, it is unknown whether yeast has an inhibitory potential for the growth of pathogenic bacteria in food. A total of 404 yeasts were screened for inhibitory activity against five Listeria monocytogenes strains. Three hundred and four of these yeasts were isolated from smear-ripened cheeses. Most of the yeasts were identified by Fourier transform infrared spectroscopy. Using an agar-membrane screening assay, a fraction of approximately 4% of the 304 red smear cheese isolates clearly inhibited growth of L. monocytogenes. Furthermore, 14 out of these 304 cheese yeasts were cocultivated with L. monocytogenes WSLC 1364 on solid medium to test the antilisterial activity of yeast in direct cell contact with Listeria. All yeasts inhibited L. monocytogenes to a low degree, which is most probably due to competition for nutrients. However, one Candida intermedia strain was able to reduce the listerial cell count by 4 log units. Another four yeasts, assigned to C. intermedia (three strains) and Kluyveromyces marxianus (one strain), repressed growth of L. monocytogenes by 3 log units. Inhibition of L. monocytogenes was clearly pronounced in the cocultivation assay, which simulates the conditions and contamination rates present on smear cheese surfaces. We found no evidence that the unknown inhibitory molecule is able to diffuse through soft agar. PMID:16391059

Intracellular β-Glucosidases CEL1a and CEL1b Are Essential for Cellulase Induction on Lactose in Trichoderma reesei

PubMed Central

Xu, Jintao; Zhao, Guolei; Kou, Yanbo; Zhang, Weixin; Zhou, Qingxin; Chen, Guanjun

2014-01-01

Lactose (1,4-O-β-d-galacto-pyranosyl-d-glucose) induces cellulolytic enzymes in Trichoderma reesei and is in fact one of the most important soluble carbon sources used to produce cellulases on an industrial level. The mechanism underlying the induction is, however, not fully understood. In this study, we investigated the cellular functions of the intracellular β-glucosidases CEL1a and CEL1b in the induction of cellulase genes by lactose in T. reesei. We demonstrated that while CEL1a and CEL1b were functionally equivalent in mediating the induction, the simultaneous absence of these intracellular β-glucosidases abolished cbh1 gene expression on lactose. d-Galactose restored the efficient cellulase gene induction in the Δcel1a strain independently of its reductive metabolism, but not in the Δcel1a Δcel1b strain. A further comparison of the transcriptional responses of the Δcel1a Δcel1b strain complemented with wild-type CEL1a or a catalytically inactive CEL1a version and the Δcel1a strain constitutively expressing CEL1a or the Kluyveromyces lactis β-galactosidase LAC4 showed that both the CEL1a protein and its glycoside hydrolytic activity were indispensable for cellulase induction by lactose. We also present evidence that intracellular β-glucosidase-mediated lactose induction is further conveyed to XYR1 to ensure the efficiently induced expression of cellulase genes. PMID:24879125

Molecular Identification and Antifungal Susceptibility Pattern of Non-albicans Candida Species Isolated from Vulvovaginal Candidiasis

PubMed Central

Nejat, Ziba Abbasi; Farahyar, Shirin; Falahati, Mehraban; Khozani, Mahtab Ashrafi; Hosseini, Aga Fateme; Faiazy, Azamsadat; Ekhtiari, Masoome; Hashemi-Hafshenjani, Saeideh

2018-01-01

Background: Vulvovaginal candidiasis (VVC) is an important health problem caused by Candida spp. The aim of this study was molecular identification, phylogenetic analysis, and evaluation of antifungal susceptibility of non-albicans Candida isolates from VVC. Methods: Vaginal secretion samples were collected from 550 vaginitis patients at Sayyad Shirazi Medical and Educational Center of Gorgan (Golestan Province, Iran) from May to October 2015. Samples were analyzed using conventional mycological and molecular approaches. Clinical isolates were analyzed with specific PCR using CGL primers, and the internal transcribed spacer region and the D1-D2 domain of the large-subunit rRNA gene were amplified and sequenced. Susceptibility to amphotericin B, fluconazole, itraconazole, and clotrimazole was determined by the guidelines of the Clinical and Laboratory Standard Institute. Results: In total, 35 non-albicans Candida isolates were identified from VVC patients. The isolates included 27 strains of Candida glabrata (77.1%), 5 Candida krusei (Pichia kudriavzevii; 14.3%), 2 Candida kefyr (Kluyveromyces marxianus; 5.7%), and 1 Candida lusitaniae (Clavispora lusitaniae; 2.9%). The fungicides itraconazole and amphotericin B were effective against all species. One isolate of C. glabrata showed resistance to fluconazole and clotrimazole, and 26 isolates of C. glabrata indicated dose-dependent susceptibility to fluconazole. C. lusitaniae was susceptible in a dose-dependent manner to fluconazole and resistant to clotrimazole. Conclusions: Non-albicans Candida spp. are common agents of vulvovaginitis, and C. glabrata is the most common species in the tested patients. PMID:28688376

Spectroscopic studies, antimicrobial activities and crystal structures of N-(2-hydroxy-3-methoxybenzalidene)1-aminonaphthalene

NASA Astrophysics Data System (ADS)

Ünver, Hüseyin; Yıldız, Mustafa; Dülger, Başaran; Özgen, Özen; Kendi, Engin; Durlu, Tahsin Nuri

2005-03-01

Schiff base N-(2-hydroxy-3-methoxybenzalidene)1-aminonaphthalene has been synthesized from the reaction of 2-hydroxy-3-methoxybenzaldehyde with 1-aminonaphthalene. The compound were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR and UV-visible techniques. The UV-visible spectra of the Schiff base were studied in polar and nonpolar solvents in acidic and basic media. The structure of the compound has been examined cyrstallographically. There are two independent molecules in the asymmetric unit. It crystallizes in the monoclinic space group P21/c, with unit cell parameters: a=14, 602(2), b=5,800(1), c=16, 899(1) Å, V=1394.4(2) Å 3, Dx=1.321 g cm -3 and Z=4. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R=0.041 of for 1179 observed reflections. The title compound's antimicrobial activities also have been studied. The antimicrobial activities of the ligand has been screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smegmatis CCM 2067, Bacillus cereus ATCC 7064 and Listeria monocytogenes ATCC 15313, the yeast cultures Candida albicans ATCC 10231, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238 and Hanseniaspora guilliermondii DSM 3432.

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance

PubMed Central

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-01-01

Aims A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. Methods A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. Results The average donepezil clearance was 7.3 l h−1 with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. Conclusion The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. PMID:24433464

Population pharmacokinetic approach to evaluate the effect of CYP2D6, CYP3A, ABCB1, POR and NR1I2 genotypes on donepezil clearance.

PubMed

Noetzli, Muriel; Guidi, Monia; Ebbing, Karsten; Eyer, Stephan; Wilhelm, Laurence; Michon, Agnès; Thomazic, Valérie; Stancu, Ioana; Alnawaqil, Abdel-Messieh; Bula, Christophe; Zumbach, Serge; Gaillard, Michel; Giannakopoulos, Panteleimon; von Gunten, Armin; Csajka, Chantal; Eap, Chin B

2014-07-01

A large interindividual variability in plasma concentrations has been reported in patients treated with donepezil, the most frequently prescribed antidementia drug. We aimed to evaluate clinical and genetic factors influencing donepezil disposition in a patient population recruited from a naturalistic setting. A population pharmacokinetic study was performed including data from 129 older patients treated with donepezil. The patients were genotyped for common polymorphisms in the metabolic enzymes CYP2D6 and CYP3A, in the electron transferring protein POR and the nuclear factor NR1I2 involved in CYP activity and expression, and in the drug transporter ABCB1. The average donepezil clearance was 7.3 l h(-1) with a 30% interindividual variability. Gender markedly influenced donepezil clearance (P < 0.01). Functional alleles of CYP2D6 were identified as unique significant genetic covariate for donepezil clearance (P < 0.01), with poor metabolizers and ultrarapid metabolizers demonstrating, respectively, a 32% slower and a 67% faster donepezil elimination compared with extensive metabolizers. The pharmacokinetic parameters of donepezil were well described by the developed population model. Functional alleles of CYP2D6 significantly contributed to the variability in donepezil disposition in the patient population and should be further investigated in the context of individual dose optimization to improve clinical outcome and tolerability of the treatment. © 2014 The British Pharmacological Society.

Differential regulation of duplicate light-dependent protochlorophyllide oxidoreductases in the diatom Phaeodactylum tricornutum

DOE PAGES

Hunsperger, Heather M.; Ford, Christopher J.; Miller, James S.; ...

2016-07-01

Diatoms (Bacilliariophyceae) encode two light-dependent protochlorophyllide oxidoreductases (POR1 and POR2) that catalyze the penultimate step of chlorophyll biosynthesis in the light. Algae live in dynamic environments whose changing light levels induce photoacclimative metabolic shifts, including altered cellular chlorophyll levels. We hypothesized that the two POR proteins may be differentially adaptive under varying light conditions. Using the diatom Phaeodactylum tricornutum as a test system, differences in POR protein abundance and por gene expression were examined when this organism was grown on an alternating light:dark cycles at different irradiances; exposed to continuous light; and challenged by a significant decrease in light availability.more » As a result, for cultures maintained on a 12h light: 12h dark photoperiod at 200μEm –2 s –1 ( 200L/D), both por genes were up-regulated during the light and down-regulated in the dark, though por1 transcript abundance rose and fell earlier than that of por2. Little concordance occurred between por1 mRNA and POR1 protein abundance. In contrast, por2 mRNA and POR2 protein abundances followed similar diurnal patterns. When 200L/D P. tricornutum cultures were transferred to continuous light ( 200L/L), the diurnal regulatory pattern of por1 mRNA abundance but not of por2 was disrupted, and POR1 but not POR2 protein abundance dropped steeply. Under 1200μEm –2 s –1 ( 1200L/D), both por1 mRNA and POR1 protein abundance displayed diurnal oscillations. A compromised diel por2 mRNA response under 1200L/D did not impact the oscillation in POR2 abundance. When cells grown at 1200L/D were then shifted to 50μEm –2 s –1 (50L/D), por1 and por2 mRNA levels decreased swiftly but briefly upon light reduction. Thereafter, POR1 but not POR2 protein levels rose significantly in response to this light stepdown.« less

A study on the stability of O{sub 2} on oxometalloporphyrins by the first principles calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubota, Yoshiyuki; Escano, Mary Clare Sison; Dy, Eben Sy

2007-05-21

The authors investigated the interaction of oxometalloporphyrins (MO(por))--specifically, MoO(por), WO(por), TiO(por), VO(por), and CrO(por)--with O{sub 2} by using first principles calculations. MoO(por) and WO(por) undergo reactions with O{sub 2}; on the other hand, TiO(por), VO(por), and CrO(por) do not. Next, they compared the interaction of MoO(por) and WO(por) with O{sub 2}. Activation barriers for the reactions of MoO(por) and WO(por) with a side-on O{sub 2} are small. For MoO(por)(O{sub 2}), the activation barrier for the reverse reaction that liberates O{sub 2} is also small; however, that for WO(por)(O{sub 2}) is large. The experimental results that photoirradiation with visible light ormore » heating of Mo {sup VI}O(tmp)(O{sub 2}) regenerates Mo {sup VI}O(tmp) by liberating O{sub 2} while W {sup VI}O(tmp)(O{sub 2}) does not [J. Tachibana, T. Imamura, and Y. Sasaki, Bull. Chem. Soc. Jpn. 71, 363 (1998)] are explained by the difference in activation barriers of the reverse reactions. This means that bonds formed between the W atom and O{sub 2} are stronger than those between the Mo atom and O{sub 2}. The bond strengths can be explained by differences in the energy levels between the highest occupied molecular orbital of MoO(por) and WO(por), which are mainly formed from the a orbitals of the central metal atom and {pi}{sup *} orbitals of O{sub 2}.« less

Type IX secretion: the generation of bacterial cell surface coatings involved in virulence, gliding motility and the degradation of complex biopolymers.

PubMed

Veith, Paul D; Glew, Michelle D; Gorasia, Dhana G; Reynolds, Eric C

2017-10-01

The Type IX secretion system (T9SS) is present in over 1000 sequenced species/strains of the Fibrobacteres-Chlorobi-Bacteroidetes superphylum. Proteins secreted by the T9SS have an N-terminal signal peptide for translocation across the inner membrane via the SEC translocon and a C-terminal signal for secretion across the outer membrane via the T9SS. Nineteen protein components of the T9SS have been identified including three, SigP, PorX and PorY that are involved in regulation. The inner membrane proteins PorL and PorM and the outer membrane proteins PorK and PorN interact and a complex comprising PorK and PorN forms a large ring structure of 50 nm in diameter. PorU, PorV, PorQ and PorZ form an attachment complex on the cell surface of the oral pathogen, Porphyromonas gingivalis. P. gingivalis T9SS substrates bind to PorV suggesting that after translocation PorV functions as a shuttle protein to deliver T9SS substrates to the attachment complex. The PorU component of the attachment complex is a novel Gram negative sortase which catalyses the cleavage of the C-terminal signal and conjugation of the protein substrates to lipopolysaccharide, anchoring them to the cell surface. This review presents an overview of the T9SS focusing on the function of T9SS substrates and machinery components. © 2017 John Wiley & Sons Ltd.

The effect of β-saturated pyrrolic rings on the electronic structures and aromaticity of magnesium porphyrin derivatives: a density functional study.

PubMed

Wan, Liang; Qi, Dongdong; Zhang, Yuexing

2011-09-01

Density functional theory (DFT) calculation on the molecular structures, molecular orbitals, electronic absorption spectra, and magnetic properties of magnesium porphyrin (MgPor) and a series of five hydrogenated magnesium porphyrin complexes with different number of β-saturated pyrrolic rings, namely MgPor-β-1Hy, MgPor-β-opp-2Hy, MgPor-β-adj-2Hy, MgPor-β-3Hy, and MgPor-β-4Hy, clarifies the red-shift of the lowest energy absorption band from chlorophyll a to bacteriochlorophyll and reveals the strong chemical stability for both of them. The energy levels of highest occupied molecular orbitals (HOMO) and HOMO-1 for MgPor are reversed upon hydrogenation at β-positions (2 and 3, 7 and 8, 12 and 13, and 17 and 18) of porphyrin ring. Along with the increase of β-saturated pyrrolic rings from 1, 2, 3, to 4, the HOMO energy increases from -4.78 eV to -3.10 eV in a regular manner. In contrast, the lowest unoccupied molecular orbitals (LUMO) energy levels of MgPor, MgPor-β-1Hy, and MgPor-β-opp-2Hy are very similar with each other. As a result, the lowest energy absorption band involving main transition from HOMO to LUMO is red-shifted from MgPor-β-1Hy to MgPor-β-opp-2Hy which is representative of chlorophyll a and bacteriochlorophyll, respectively. Natural hydroporphyrins represented by MgPor, MgPor-β-1Hy, and MgPor-β-opp-2Hy have turned out to be aromatic and stable enough, in good accordance with the ubiquity of their derivatives in the nature. In contrast, MgPor-β-adj-2Hy, MgPor-β-3Hy, and MgPor-β-4Hy with relatively weak aromaticity seem to be unstable and therefore were not found in nature. Copyright © 2011 Elsevier Inc. All rights reserved.

Legal Knowledge as a Tool for Social Change: La Mesa por la Vida y la Salud de las Mujeres as an Expert on Colombian Abortion Law.

PubMed

González Vélez, Ana Cristina; Jaramillo, Isabel Cristina

2017-06-01

In May 2006, Colombia's Constitutional Court liberalized abortion, introducing three circumstances under which the procedure would not be considered a crime: (1) rape or incest; (2) a risk to the woman's health or life; and (3) fetal malformations incompatible with life. Immediately following the court's ruling, known as Sentence C-355, members of La Mesa por la Vida y Salud de las Mujeres (hereinafter La Mesa) began to mobilize to ensure the decision's implementation, bearing in mind the limited impact that the legal framework endorsed by the court has had in other countries in the region. We argue that La Mesa's strategy is an innovative one in the field of legal mobilization insofar as it presumes that law can be shaped not just by public officials and universities but also by social actors engaged in the creation and diffusion of legal knowledge. In this regard, La Mesa has become a legal expert on abortion by accumulating knowledge about the multiple legal rules affecting the practice of abortion and about the situations in which these rules are to be applied. In addition, by becoming a legal expert, La Mesa has been able to persuade health providers that they will not risk criminal prosecution or being fired if they perform abortions. We call this effect of legal mobilization a "pedagogical effect" insofar as it involves the production of expertise and appropriation of knowledge by health professionals. We conclude by discussing La Mesa's choice to become a legal expert on abortion as opposed to recruiting academics to do this work or encouraging women to produce and disseminate this knowledge.

The Composition of Camembert Cheese-Ripening Cultures Modulates both Mycelial Growth and Appearance

PubMed Central

Lessard, Marie-Hélène; Bélanger, Gaétan; St-Gelais, Daniel

2012-01-01

The fungal microbiota of bloomy-rind cheeses, such as Camembert, forms a complex ecosystem that has not been well studied, and its monitoring during the ripening period remains a challenge. One limitation of enumerating yeasts and molds on traditional agar media is that hyphae are multicellular structures, and colonies on a petri dish rarely develop from single cells. In addition, fungi tend to rapidly invade agar surfaces, covering small yeast colonies and resulting in an underestimation of their number. In this study, we developed a real-time quantitative PCR (qPCR) method using TaqMan probes to quantify a mixed fungal community containing the most common dairy yeasts and molds: Penicillium camemberti, Geotrichum candidum, Debaryomyces hansenii, and Kluyveromyces lactis on soft-cheese model curds (SCMC). The qPCR method was optimized and validated on pure cultures and used to evaluate the growth dynamics of a ripening culture containing P. camemberti, G. candidum, and K. lactis on the surface of the SCMC during a 31-day ripening period. The results showed that P. camemberti and G. candidum quickly dominated the ecosystem, while K. lactis remained less abundant. When added to this ecosystem, D. hansenii completely inhibited the growth of K. lactis in addition to reducing the growth of the other fungi. This result was confirmed by the decrease in the mycelium biomass on SCMC. This study compares culture-dependent and qPCR methods to successfully quantify complex fungal microbiota on a model curd simulating Camembert-type cheese. PMID:22247164

Promoter-Terminator Gene Loops Affect Alternative 3'-End Processing in Yeast.

PubMed

Lamas-Maceiras, Mónica; Singh, Badri Nath; Hampsey, Michael; Freire-Picos, María A

2016-04-22

Many eukaryotic genes undergo alternative 3'-end poly(A)-site selection producing transcript isoforms with 3'-UTRs of different lengths and post-transcriptional fates. Gene loops are dynamic structures that juxtapose the 3'-ends of genes with their promoters. Several functions have been attributed to looping, including memory of recent transcriptional activity and polarity of transcription initiation. In this study, we investigated the relationship between gene loops and alternative poly(A)-site. Using the KlCYC1 gene of the yeast Kluyveromyces lactis, which includes a single promoter and two poly(A) sites separated by 394 nucleotides, we demonstrate in two yeast species the formation of alternative gene loops (L1 and L2) that juxtapose the KlCYC1 promoter with either proximal or distal 3'-end processing sites, resulting in the synthesis of short and long forms of KlCYC1 mRNA. Furthermore, synthesis of short and long mRNAs and formation of the L1 and L2 loops are growth phase-dependent. Chromatin immunoprecipitation experiments revealed that the Ssu72 RNA polymerase II carboxyl-terminal domain phosphatase, a critical determinant of looping, peaks in early log phase at the proximal poly(A) site, but as growth phase advances, it extends to the distal site. These results define a cause-and-effect relationship between gene loops and alternative poly(A) site selection that responds to different physiological signals manifested by RNA polymerase II carboxyl-terminal domain phosphorylation status. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of freeze-drying on viability and in vitro probiotic properties of a mixture of lactic acid bacteria and yeasts isolated from kefir.

PubMed

Bolla, Patricia A; Serradell, María de los Angeles; de Urraza, Patricio J; De Antoni, Graciela L

2011-02-01

The effect of freeze-drying on viability and probiotic properties of a microbial mixture containing selected bacterial and yeast strains isolated from kefir grains (Lactobacillus kefir, Lactobacillus plantarum, Lactococcus lactis, Saccharomyces cerevisiae and Kluyveromyces marxianus) was studied. The microorganisms were selected according to their potentially probiotic properties in vitro already reported. Two types of formulations were performed, a microbial mixture (MM) suspended in milk and a milk product fermented with MM (FMM). To test the effect of storage on viability of microorganisms, MM and FMM were freeze-dried and maintained at 4°C for six months. After 180 days of storage at 4°C, freeze-dried MM showed better survival rates for each strain than freeze-dried FMM. The addition of sugars (trehalose or sucrose) did not improve the survival rates of any of the microorganisms after freeze-drying. Freeze-drying did not affect the capacity of MM to inhibit growth of Shigella sonnei in vitro, since the co-incubation of this pathogen with freeze-dried MM produced a decrease of 2 log in Shigella viability. The safety of freeze-dried MM was tested in mice and non-translocation of microorganisms to liver or spleen was observed in BALB/c mice feed ad libitum during 7 or 20 days. To our knowledge, this is the first report about the effect of freeze-drying on viability, in vitro probiotic properties and microbial translocation of a mixture containing different strains of both bacteria and yeasts isolated from kefir.

Survival of cheese-ripening microorganisms in a dynamic simulator of the gastrointestinal tract.

PubMed

Adouard, Nadège; Magne, Laurent; Cattenoz, Thomas; Guillemin, Hervé; Foligné, Benoît; Picque, Daniel; Bonnarme, Pascal

2016-02-01

A mixture of nine microorganisms (six bacteria and three yeasts) from the microflora of surface-ripened cheeses were subjected to in vitro digestive stress in a three-compartment "dynamic gastrointestinal digester" (DIDGI). We studied the microorganisms (i) grown separately in culture medium only (ii) grown separately in culture medium and then mixed, (iii) grown separately in culture medium and then included in a rennet gel and (iv) grown together in smear-ripened cheese. The yeasts Geotrichum candidum, Kluyveromyces lactis and Debaryomyces hansenii, were strongly resistant to the whole DIDGI process (with a drop in viable cell counts of less than <1 log CFU mL(-1)) and there were no significant differences between lab cultures and cheese-grown cultures. Ripening bacteria such as Hafnia alvei survived gastric stress less well when grown in cheese (with no viable cells after 90 min of exposure of the cheese matrix, compared with 6 CFU mL(-1) in lab cultures). The ability of Corynebacterium casei and Staphylococcus equorum to withstand digestive stress was similar for cheese and pure culture conditions. When grow in a cheese matrix, Brevibacterium aurantiacum and Arthrobacter arilaitensis were clearly more sensitive to the overall digestive process than when grown in pure cultures. Lactococcus lactis displayed poorer survival in gastric and duodenal compartments when it had been grown in cheese. In vivo experiments in BALB/c mice agreed with the DIDGI experiments and confirmed the latter's reliability. Copyright © 2015. Published by Elsevier Ltd.

Biodiversity of antifungal lactic acid bacteria isolated from raw milk samples from cow, ewe and goat over one-year period.

PubMed

Delavenne, E; Mounier, J; Déniel, F; Barbier, G; Le Blay, G

2012-04-16

Antifungal lactic acid bacteria (ALAB) biodiversity was evaluated in raw milk from ewe, cow and goat over one year period. Lactic acid bacteria were enumerated using 8 semi-selective media, and systematically screened for their antifungal activity against 4 spoilage fungi commonly encountered in dairy products. Depending on the selective medium, between 0.05% (Elliker agar) and 5.5% (LAMVAB agar) screened colonies showed an antifungal activity. The great majority of these active colonies originated from cow (49%) and goat (43%) milks, whereas only 8% were isolated from ewe milk. Penicillium expansum was the most frequently inhibited fungus with 48.5% of colonies active against P. expansum among the 1235 isolated, followed by Mucor plumbeus with 30.6% of active colonies, Kluyveromyces lactis with only 12.1% of active colonies and Pichia anomala with 8.7% of active colonies. In the tested conditions, 94% of the sequenced active colonies belonged to Lactobacillus. Among them, targeted fungal species differed according to the Lactobacillus group, whose presence largely depended on year period and milk origin. The Lb. casei and Lb. reuteri groups, predominantly recovered in summer/fall, were overrepresented in the population targeting M. plumbeus, whereas isolates from the Lb. plantarum group, predominantly recovered in spring, were overrepresented in the population targeting K. lactis, the ones belonging to the Lb. buchneri group, predominantly recovered in spring, were overrepresented in the population targeting P. anomala. Raw milk, especially cow and goat milks from the summer/fall period appeared to be a productive reservoir for antifungal lactobacilli. Copyright © 2012 Elsevier B.V. All rights reserved.

Engineering a cardosin B-derived rennet for sheep and goat cheese manufacture.

PubMed

Almeida, Carla Malaquias; Gomes, David; Faro, Carlos; Simões, Isaura

2015-01-01

Different sheep and goat cheeses with world-renowned excellence are produced using aqueous extracts of Cynara cardunculus flowers as coagulants. However, the use of this vegetable rennet is mostly limited to artisanal scale production, and no effective solutions to large-scale industrial applications have been reported so far. In this sense, the development of a synthetic rennet based on the most abundant cardoon milk-clotting enzymes (cardosins) would emerge as a solution for scalability of production and for application of these proteases as alternative rennets in dairy industry. In this work, we report the development of a new cardosin B-derived rennet produced in the generally regarded as safe (GRAS) yeast Kluyveromyces lactis. Using a stepwise optimization strategy-consisting of culture media screening, complemented with a protein engineering approach with removal of the plant-specific domain, and a codon optimization step-we successfully improved cardosin B production yield (35×) in K. lactis. We demonstrated that the secreted enzyme displays similar proteolytic properties, such as casein digestion profiles as well as optimum pH (pH 4.5) and temperature (40 °C), with those of native cardosin B. From this optimization process resulted the rennet preparation Vegetable Rennet (VRen), requiring no downstream protein purification steps. The effectiveness of VRen in cheese production was demonstrated by manufacturing sheep, goat, and cow cheeses. Interestingly, the use of VRen resulted in a higher cheese yield for all three types of cheese when compared with synthetic chymosin. Altogether, these results clearly position VRen as an alternative/innovative coagulant for the cheese-making industry.

Sequencing-Based Analysis of the Bacterial and Fungal Composition of Kefir Grains and Milks from Multiple Sources

PubMed Central

Marsh, Alan J.; O’Sullivan, Orla; Hill, Colin; Ross, R. Paul; Cotter, Paul D.

2013-01-01

Kefir is a fermented milk-based beverage to which a number of health-promoting properties have been attributed. The microbes responsible for the fermentation of milk to produce kefir consist of a complex association of bacteria and yeasts, bound within a polysaccharide matrix, known as the kefir grain. The consistency of this microbial population, and that present in the resultant beverage, has been the subject of a number of previous, almost exclusively culture-based, studies which have indicated differences depending on geographical location and culture conditions. However, culture-based identification studies are limited by virtue of only detecting species with the ability to grow on the specific medium used and thus culture-independent, molecular-based techniques offer the potential for a more comprehensive analysis of such communities. Here we describe a detailed investigation of the microbial population, both bacterial and fungal, of kefir, using high-throughput sequencing to analyse 25 kefir milks and associated grains sourced from 8 geographically distinct regions. This is the first occasion that this technology has been employed to investigate the fungal component of these populations or to reveal the microbial composition of such an extensive number of kefir grains or milks. As a result several genera and species not previously identified in kefir were revealed. Our analysis shows that the bacterial populations in kefir are dominated by 2 phyla, the Firmicutes and the Proteobacteria. It was also established that the fungal populations of kefir were dominated by the genera Kazachstania, Kluyveromyces and Naumovozyma, but that a variable sub-dominant population also exists. PMID:23894461

The use of controlled microbial cenoses in producers' link to increase steady functioning of artificial ecosystems

NASA Astrophysics Data System (ADS)

Somova, Lydia; Mikheeva, Galina; Somova, Lydia

The life support systems (LSS) for long-term missions are to use cycling-recycling systems, including biological recycling. Simple ecosystems include 3 links: producers (plants), consumers (man, animals) and reducers (microorganisms). Microorganisms are substantial component of every link of LSS. Higher plants are the traditional regenerator of air and producer of food. They should be used in many successive generations of their reproduction in LSS. Controlled microbiocenoses can increase productivity of producer's link and protect plants from infections. The goal of this work was development of methodological bases of formation of stable, controlled microbiocenoses, intended for increase of productivity of plants and for obtaining ecologically pure production of plants. Main results of our investigations: 1. Experimental microbiocenoses, has been produced in view of the developed methodology on the basis of natural association of microorganisms by long cultivation on specially developed medium. Dominating groups are bacteria of genera: Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Rhodopseudomonas and yeast of genera: Kluyveromyces, Saccharomyces, Torulopsis. 2. Optimal parameters of microbiocenosis cultivation (t, pH, light exposure, biogenic elements concentrations) were experimentally established. Conditions of cultivation on which domination of different groups of microbiocenosis have been found. 3. It was shown, that processing of seeds of wheat, oats, bulbs and plants Allium cepa L. (an onions) with microbial association raised energy of germination of seeds and bulbs and promoted the increase (on 20-30 %) of growth green biomass and root system of plants in comparison with the control. This work is supported by grant, Yenissey , 07-04-96806

Sequencing-based analysis of the bacterial and fungal composition of kefir grains and milks from multiple sources.

PubMed

Marsh, Alan J; O'Sullivan, Orla; Hill, Colin; Ross, R Paul; Cotter, Paul D

2013-01-01

Kefir is a fermented milk-based beverage to which a number of health-promoting properties have been attributed. The microbes responsible for the fermentation of milk to produce kefir consist of a complex association of bacteria and yeasts, bound within a polysaccharide matrix, known as the kefir grain. The consistency of this microbial population, and that present in the resultant beverage, has been the subject of a number of previous, almost exclusively culture-based, studies which have indicated differences depending on geographical location and culture conditions. However, culture-based identification studies are limited by virtue of only detecting species with the ability to grow on the specific medium used and thus culture-independent, molecular-based techniques offer the potential for a more comprehensive analysis of such communities. Here we describe a detailed investigation of the microbial population, both bacterial and fungal, of kefir, using high-throughput sequencing to analyse 25 kefir milks and associated grains sourced from 8 geographically distinct regions. This is the first occasion that this technology has been employed to investigate the fungal component of these populations or to reveal the microbial composition of such an extensive number of kefir grains or milks. As a result several genera and species not previously identified in kefir were revealed. Our analysis shows that the bacterial populations in kefir are dominated by 2 phyla, the Firmicutes and the Proteobacteria. It was also established that the fungal populations of kefir were dominated by the genera Kazachstania, Kluyveromyces and Naumovozyma, but that a variable sub-dominant population also exists.

Yeasts are essential for cocoa bean fermentation.

PubMed

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2014-03-17

Cocoa beans (Theobroma cacao) are the major raw material for chocolate production and fermentation of the beans is essential for the development of chocolate flavor precursors. In this study, a novel approach was used to determine the role of yeasts in cocoa fermentation and their contribution to chocolate quality. Cocoa bean fermentations were conducted with the addition of 200ppm Natamycin to inhibit the growth of yeasts, and the resultant microbial ecology and metabolism, bean chemistry and chocolate quality were compared with those of normal (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii and Kluyveromyces marxianus, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in the control fermentation. In fermentations with the presence of Natamycin, the same bacterial species grew but yeast growth was inhibited. Physical and chemical analyses showed that beans fermented without yeasts had increased shell content, lower production of ethanol, higher alcohols and esters throughout fermentation and lesser presence of pyrazines in the roasted product. Quality tests revealed that beans fermented without yeasts were purplish-violet in color and not fully brown, and chocolate prepared from these beans tasted more acid and lacked characteristic chocolate flavor. Beans fermented with yeast growth were fully brown in color and gave chocolate with typical characters which were clearly preferred by sensory panels. Our findings demonstrate that yeast growth and activity were essential for cocoa bean fermentation and the development of chocolate characteristics. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Fungal Colonization and Biodeterioration of Plasticized Polyvinyl Chloride

PubMed Central

Webb, Jeremy S.; Nixon, Marianne; Eastwood, Ian M.; Greenhalgh, Malcolm; Robson, Geoffrey D.; Handley, Pauline S.

2000-01-01

Significant substratum damage can occur when plasticized PVC (pPVC) is colonized by microorganisms. We investigated microbial colonization of pPVC in an in situ, longitudinal study. Pieces of pPVC containing the plasticizers dioctyl phthalate and dioctyl adipate (DOA) were exposed to the atmosphere for up to 2 years. Fungal and bacterial populations were quantified, and colonizing fungi were identified by rRNA gene sequencing and morphological characteristics. Aureobasidium pullulans was the principal colonizing fungus, establishing itself on the pPVC between 25 and 40 weeks of exposure. A group of yeasts and yeast-like fungi, including Rhodotorula aurantiaca and Kluyveromyces spp., established themselves on the pPVC much later (after 80 weeks of exposure). Numerically, these organisms dominated A. pullulans after 95 weeks, with a mean viable count ± standard error of 1,000 ± 200 yeast CFU cm−2, compared to 390 ± 50 A. pullulans CFU cm−2. No bacterial colonization was observed. We also used in vitro tests to characterize the deteriogenic properties of fungi isolated from the pPVC. All strains of A. pullulans tested could grow with the intact pPVC formulation as the sole source of carbon, degrade the plasticizer DOA, produce extracellular esterase, and cause weight loss of the substratum during growth in vitro. In contrast, several yeast isolates could not grow on pPVC or degrade DOA. These results suggest that microbial succession may occur during the colonization of pPVC and that A. pullulans is critical to the establishment of a microbial community on pPVC. PMID:10919769

Electron transport chain in a thermotolerant yeast.

PubMed

Mejía-Barajas, Jorge A; Martínez-Mora, José A; Salgado-Garciglia, Rafael; Noriega-Cisneros, Ruth; Ortiz-Avila, Omar; Cortés-Rojo, Christian; Saavedra-Molina, Alfredo

2017-04-01

Yeasts capable of growing and surviving at high temperatures are regarded as thermotolerant. For appropriate functioning of cellular processes and cell survival, the maintenance of an optimal redox state is critical of reducing and oxidizing species. We studied mitochondrial functions of the thermotolerant Kluyveromyces marxianus SLP1 and the mesophilic OFF1 yeasts, through the evaluation of its mitochondrial membrane potential (ΔΨ m ), ATPase activity, electron transport chain (ETC) activities, alternative oxidase activity, lipid peroxidation. Mitochondrial membrane potential and the cytoplasmic free Ca 2+ ions (Ca 2+ cyt) increased in the SLP1 yeast when exposed to high temperature, compared with the mesophilic yeast OFF1. ATPase activity in the mesophilic yeast diminished 80% when exposed to 40° while the thermotolerant SLP1 showed no change, despite an increase in the mitochondrial lipid peroxidation. The SLP1 thermotolerant yeast exposed to high temperature showed a diminution of 33% of the oxygen consumption in state 4. The uncoupled state 3 of oxygen consumption did not change in the mesophilic yeast when it had an increase of temperature, whereas in the thermotolerant SLP1 yeast resulted in an increase of 2.5 times when yeast were grown at 30 o , while a decrease of 51% was observed when it was exposed to high temperature. The activities of the ETC complexes were diminished in the SLP1 when exposed to high temperature, but also it was distinguished an alternative oxidase activity. Our results suggest that the mitochondria state, particularly ETC state, is an important characteristic of the thermotolerance of the SLP1 yeast strain.

Effect of P450 Oxidoreductase Polymorphisms on the Metabolic Activities of Ten Cytochrome P450s Varied by Polymorphic CYP Genotypes in Human Liver Microsomes.

PubMed

Fang, Yan; Gao, Na; Tian, Xin; Zhou, Jun; Zhang, Hai-Feng; Gao, Jie; He, Xiao-Pei; Wen, Qiang; Jia, Lin-Jing; Jin, Han; Qiao, Hai-Ling

2018-06-27

Background/ Aims: Little is known about the effect of P450 oxidoreductase (POR) gene polymorphisms on the activities of CYPs with multiple genotypes. We genotyped 102 human livers for 18 known POR single nucleotide polymorphisms (SNPs) with allelic frequencies greater than 1% as well as for 27 known SNPs in 10 CYPs. CYP enzyme activities in microsomes prepared from these livers were determined by measuring probe substrate metabolism by high performance liquid chromatograph. We found that the effects of the 18 POR SNPs on 10 CYP activities were CYP genotype-dependent. The POR mutations were significantly associated with decreased overall Km for CYP2B6 and 2E1, and specific genotypes within CYP1A2, 2A6, 2B6, 2C8, 2D6 and 2E1 were identified as being affected by these POR SNPs. Notably, the effect of a specific POR mutation on the activity of a CYP genotype could not be predicted from other CYP genotypes of even the same CYP. When combining one POR SNP with other POR SNPs, a hitherto unrecognized effect of multiple-site POR gene polymorphisms (MSGP) on CYP activity was uncovered, which was not necessarily consistent with the effect of either single POR SNP. The effects of POR SNPs on CYP activities were not only CYP-dependent, but more importantly, CYP genotype-dependent. Moreover, the effect of a POR SNP alone and in combination with other POR SNPs (MSGP) was not always consistent, nor predictable. Understanding the impact of POR gene polymorphisms on drug metabolism necessitates knowing the complete SNP complement of POR and the genotype of the relevant CYPs. © 2018 The Author(s). Published by S. Karger AG, Basel.

Evaluating Por Nuestra Salud: A Feasibility Study.

PubMed

Marshall, Brenda; Gonzales, Gustavo; Kernan, William

2016-01-01

This feasibility study evaluated the impact of a culturally consistent diabetes educational program, led by a Latino pastor, on Latino community diabetes knowledge levels. Latino adults were recruited from two churches serving Latino populations, one identified as intervention, the other as nonintervention. Both churches received the American Diabetes Association's booklets on diabetes education, "Four Steps to Control Your Diabetes for Life." The intervention group also received weekly reviews of the booklet's information from the church pastor, who was educated about diabetes by a Latino family nurse practitioner. Pre- and postintervention levels of diabetes knowledge were measured using the Diabetes Knowledge Questionnaire. Mean changes in the Diabetes Knowledge Questionnaire (DKQ-24) survey from pretest to posttest indicated a significant increase in knowledge in both groups. Only the grades for the participants from the pastor-led group, however, moved from failure in knowledge to high levels of passing. One hundred percent of intervention group participants reported having read the literature. This pilot study supports the feasibility of a local Latino pastor, as a culturally consistent diabetes educator, to increase Latino parishioner's knowledge of diabetes. © 2015 Society for Public Health Education.

Heterologous expression of equine CYP3A94 and investigation of a tunable system to regulate co-expressed NADPH P450 oxidoreductase levels.

PubMed

Dettwiler, Ramona; Schmitz, Andrea L; Plattet, Philippe; Zielinski, Jana; Mevissen, Meike

2014-01-01

The activity of cytochrome P450 enzymes depends on the enzyme NADPH P450 oxidoreductase (POR). The aim of this study was to investigate the activity of the equine CYP3A94 using a system that allows to regulate the POR protein levels in mammalian cells. CYP3A94 and the equine POR were heterologously expressed in V79 cells. In the system used, the POR protein regulation is based on a destabilizing domain (DD) that transfers its instability to a fused protein. The resulting fusion protein is therefore degraded by the ubiquitin-proteasome system (UPS). Addition of "Shield-1" prevents the DD fusion protein from degradation. The change of POR levels at different Shield-1 concentrations was demonstrated by cytochrome c reduction, Western immunoblot analysis, and immunocytochemistry. The alteration of CYP3A94 activity was investigated using a substrate (BFC) known to detect CYP3A4 activity. Equine CYP3A94 was demonstrated to be metabolically active and its activity could be significantly elevated by co-expression of POR. Cytochrome c reduction was significantly increased in V79-CYP3A94/DD-POR cells compared to V79-CYP3A94 cells. Surprisingly, incubation with different Shield-1 concentrations resulted in a decrease in POR protein shown by Western immunoblot analysis. Cytochrome c reduction did not change significantly, but the CYP3A94 activity decreased more than 4-fold after incubation with 500 nM and 1 µM Shield-1 for 24 hours. No differences were obtained when V79-CYP3A94 POR cells with and without Shield-1 were compared. The basal activity levels of V79-CYP3A94/DD-POR cells were unexpectedly high, indicating that DD/POR is not degraded without Shield-1. Shield-1 decreased POR protein levels and CYP3A94 activity suggesting that Shield-1 might impair POR activity by an unknown mechanism. Although regulation of POR with the pPTuner system could not be obtained, the cell line V79-CYP3A94/DD-POR system can be used for further experiments to characterize the equine CYP3A94

Primary language and cultural background as factors in resident burnout in medical specialties: a study in a bilingual US city.

PubMed

Afzal, Khalid I; Khan, Farhan M; Mulla, Zuber; Akins, Ralista; Ledger, Elizabeth; Giordano, Frank L

2010-07-01

The aim of this study was to identify the degree of burnout among resident physicians enrolled in seven postgraduate training programs at Texas Tech University Health Sciences Center (TTUHSC), Paul L. Foster School of Medicine, El Paso, Texas, as it related to residents' age, gender, marital status, number of hours worked per week, primary language, race/ethnicity, and cultural background. : The Maslach Burnout Inventory Human Service Survey (MBI) was administered to measure the level of burnout according to the prevalence of emotional exhaustion (EE), depersonalization (DP), and reduced personal accomplishment (PA). : Eighty-one percent of the residents at TTUHSC participated in the study. Residents raised in the United States or Canada comprised 28% and 35% of the study, and all reported English as their primary language. The EE scale was significant for obstetrics/gynecology (OB/GYN) residents (prevalence odds ratio [POR] = 13.55, P = 0.02) and psychiatry (PSY) residents (POR = 6.50, P = 0.03). Emergency medicine (EM) residents (POR = 23.35, P = 0.002), OB/GYN (POR = 10.89, P = 0.02), and general surgery (GS) (POR = 6.24, P = 0.03) residents had high DP. Internal medicine (IM) residents (primarily Spanish-speaking) reported significantly low EE (POR = 0.22, P = 0.03) and PA (POR = 0.09, P = 0.001) scores. Residents from the United States or Canada who reported English as their primary language and noted their race as white, had high EE (POR = 3.06, P = 0.03; POR = 5.61, P = 0.0001; POR = 2.91, P = 0.004), DP (POR = 3.19, P = 0.02; POR = 8.34, P < or = 0.0001; POR = 4.70, P < or = 0.0001) and PA (POR = 2.61, P = 0.02; POR = 2.35, P = 0.05, POR 0.29, P = 0.3) scores. Using valid measures, this pilot study identified a statistically significant relationship between burnout and residents' race/ethnicity, primary language, and cultural background. Larger studies with similar focus would be necessary to generalize these findings. At-risk residents in bilingual

Reduction in hepatic drug metabolizing CYP3A4 activities caused by P450 oxidoreductase mutations identified in patients with disordered steroid metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flueck, Christa E.; Mullis, Primus E.; Pandey, Amit V., E-mail: amit@pandeylab.org

2010-10-08

Research highlights: {yields} Cytochrome P450 3A4 (CYP3A4), metabolizes 50% of drugs in clinical use and requires NADPH-P450 reductase (POR). {yields} Mutations in human POR cause congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. {yields} We are reporting that mutations in POR may reduce CYP3A4 activity. {yields} POR mutants Y181D, A457H, Y459H, V492E and R616X lost 99%, while A287P, C569Y and V608F lost 60-85% CYP3A4 activity. {yields} Reduction of CYP3A4 activity may cause increased risk of drug toxicities/adverse drug reactions in patients with POR mutations. -- Abstract: Cytochrome P450 3A4 (CYP3A4), the major P450 present in human liver metabolizesmore » approximately half the drugs in clinical use and requires electrons supplied from NADPH through NADPH-P450 reductase (POR, CPR). Mutations in human POR cause a rare form of congenital adrenal hyperplasia from diminished activities of steroid metabolizing P450s. In this study we examined the effect of mutations in POR on CYP3A4 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified CYP3A4 to perform kinetic studies. We are reporting that mutations in POR identified in patients with disordered steroidogenesis/Antley-Bixler syndrome (ABS) may reduce CYP3A4 activity, potentially affecting drug metabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had more than 99% loss of CYP3A4 activity, while POR mutations A287P, C569Y and V608F lost 60-85% activity. Loss of CYP3A4 activity may result in increased risk of drug toxicities and adverse drug reactions in patients with POR mutations.« less

Altered heme catabolism by heme oxygenase-1 caused by mutations in human NADPH cytochrome P450 reductase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandey, Amit V., E-mail: amit@pandeylab.org; Flueck, Christa E.; Mullis, Primus E.

2010-09-24

Research highlights: {yields} Mutations in POR identified from patients lead to reduced HO-1 activities. {yields} POR mutation Y181D affecting FMN binding results in total loss of HO-1 activity. {yields} POR mutations A287P, C569Y and V608F, lost 50-70% activity. {yields} Mutations in FAD binding domain, R457H, Y459H and V492E lost all HO-1 activity. {yields} POR polymorphisms P228L, R316W, G413S, A503V and G504R have normal activity. -- Abstract: Human heme oxygenase-1 (HO-1) carries out heme catabolism supported by electrons supplied from the NADPH through NADPH P450 reductase (POR, CPR). Previously we have shown that mutations in human POR cause a rare formmore » of congenital adrenal hyperplasia. In this study, we have evaluated the effects of mutations in POR on HO-1 activity. We used purified preparations of wild type and mutant human POR and in vitro reconstitution with purified HO-1 to measure heme degradation in a coupled assay using biliverdin reductase. Here we show that mutations in POR found in patients may reduce HO-1 activity, potentially influencing heme catabolism in individuals carrying mutant POR alleles. POR mutants Y181D, A457H, Y459H, V492E and R616X had total loss of HO-1 activity, while POR mutations A287P, C569Y and V608F lost 50-70% activity. The POR variants P228L, R316W and G413S, A503V and G504R identified as polymorphs had close to WT activity. Loss of HO-1 activity may result in increased oxidative neurotoxicity, anemia, growth retardation and iron deposition. Further examination of patients affected with POR deficiency will be required to assess the metabolic effects of reduced HO-1 activity in affected individuals.« less

Heterologous Expression of Equine CYP3A94 and Investigation of a Tunable System to Regulate Co-Expressed NADPH P450 Oxidoreductase Levels

PubMed Central

Dettwiler, Ramona; Schmitz, Andrea L.; Plattet, Philippe; Zielinski, Jana; Mevissen, Meike

2014-01-01

The activity of cytochrome P450 enzymes depends on the enzyme NADPH P450 oxidoreductase (POR). The aim of this study was to investigate the activity of the equine CYP3A94 using a system that allows to regulate the POR protein levels in mammalian cells. CYP3A94 and the equine POR were heterologously expressed in V79 cells. In the system used, the POR protein regulation is based on a destabilizing domain (DD) that transfers its instability to a fused protein. The resulting fusion protein is therefore degraded by the ubiquitin-proteasome system (UPS). Addition of “Shield-1” prevents the DD fusion protein from degradation. The change of POR levels at different Shield-1 concentrations was demonstrated by cytochrome c reduction, Western immunoblot analysis, and immunocytochemistry. The alteration of CYP3A94 activity was investigated using a substrate (BFC) known to detect CYP3A4 activity. Equine CYP3A94 was demonstrated to be metabolically active and its activity could be significantly elevated by co-expression of POR. Cytochrome c reduction was significantly increased in V79-CYP3A94/DD-POR cells compared to V79-CYP3A94 cells. Surprisingly, incubation with different Shield-1 concentrations resulted in a decrease in POR protein shown by Western immunoblot analysis. Cytochrome c reduction did not change significantly, but the CYP3A94 activity decreased more than 4-fold after incubation with 500 nM and 1 µM Shield-1 for 24 hours. No differences were obtained when V79-CYP3A94 POR cells with and without Shield-1 were compared. The basal activity levels of V79-CYP3A94/DD-POR cells were unexpectedly high, indicating that DD/POR is not degraded without Shield-1. Shield-1 decreased POR protein levels and CYP3A94 activity suggesting that Shield-1 might impair POR activity by an unknown mechanism. Although regulation of POR with the pPTuner system could not be obtained, the cell line V79-CYP3A94/DD-POR system can be used for further experiments to characterize the equine CYP3A

P450 oxidoreductase deficiency: a disorder of steroidogenesis with multiple clinical manifestations.

PubMed

Miller, Walter L

2012-10-23

Cytochrome P450 enzymes catalyze the biosynthesis of steroid hormones and metabolize drugs. There are seven human type I P450 enzymes in mitochondria and 50 type II enzymes in endoplasmic reticulum. Type II enzymes, including both drug-metabolizing and some steroidogenic enzymes, require electron donation from a two-flavin protein, P450 oxidoreductase (POR). Although knockout of the POR gene causes embryonic lethality in mice, we discovered human POR deficiency as a disorder of steroidogenesis associated with the Antley-Bixler skeletal malformation syndrome and found mild POR mutations in phenotypically normal adults with infertility. Assay results of mutant forms of POR using the traditional but nonphysiologic assay (reduction of cytochrome c) did not correlate with patient phenotypes; assays based on the 17,20 lyase activity of P450c17 (CYP17) correlated with clinical phenotypes. The POR sequence in 842 normal individuals revealed many polymorphisms; amino acid sequence variant A503V is encoded by ~28% of human alleles. POR A503V has about 60% of wild-type activity in assays with CYP17, CYP2D6, and CYP3A4, but nearly wild-type activity with P450c21, CYP1A2, and CYP2C19. Activity of a particular POR variant with one P450 enzyme will not predict its activity with another P450 enzyme: Each POR-P450 combination must be studied individually. Human POR transcription, initiated from an untranslated exon, is regulated by Smad3/4, thyroid receptors, and the transcription factor AP-2. A promoter polymorphism reduces transcription to 60% in liver cells and to 35% in adrenal cells. POR deficiency is a newly described disorder of steroidogenesis, and POR variants may account for some genetic variation in drug metabolism.

Evolutionary dynamics of hAT DNA transposon families in Saccharomycetaceae.

PubMed

Sarilar, Véronique; Bleykasten-Grosshans, Claudine; Neuvéglise, Cécile

2014-12-21

Transposable elements (TEs) are widespread in eukaryotes but uncommon in yeasts of the Saccharomycotina subphylum, in terms of both host species and genome fraction. The class II elements are especially scarce, but the hAT element Rover is a noteworthy exception that deserves further investigation. Here, we conducted a genome-wide analysis of hAT elements in 40 ascomycota. A novel family, Roamer, was found in three species, whereas Rover was detected in 15 preduplicated species from Kluyveromyces, Eremothecium, and Lachancea genera, with up to 41 copies per genome. Rover acquisition seems to have occurred by horizontal transfer in a common ancestor of these genera. The detection of remote Rover copies in Naumovozyma dairenensis and in the sole Saccharomyces cerevisiae strain AWRI1631, without synteny, suggests that two additional independent horizontal transfers took place toward these genomes. Such patchy distribution of elements prevents any anticipation of TE presence in incoming sequenced genomes, even closely related ones. The presence of both putative autonomous and defective Rover copies, as well as their diversification into five families, indicate particular dynamics of Rover elements in the Lachancea genus. Especially, we discovered the first miniature inverted-repeat transposable elements (MITEs) to be described in yeasts, together with their parental autonomous copies. Evidence of MITE insertion polymorphism among Lachancea waltii strains suggests their recent activity. Moreover, 40% of Rover copies appeared to be involved in chromosome rearrangements, showing the large structural impact of TEs on yeast genome and opening the door to further investigations to understand their functional and evolutionary consequences. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Controlled production of Camembert-type cheeses. Part II. Changes in the concentration of the more volatile compounds.

PubMed

Leclercq-Perlat, Marie-Noëlle; Latrille, Eric; Corrieu, Georges; Spinnler, Henry-Eric

2004-08-01

Flavour generation in cheese is a major aspect of ripening. In order to enhance aromatic qualities it is necessary to better understand the chemical and microbiological changes. Experimental Camembert-type cheeses were prepared in duplicate from pasteurized milk inoculated with Kluyveromyces lactis, Geotrichum candidum, Penicillium camemberti and Brevibacterium linens under aseptic conditions. Two replicates performed under controlled conditions of temperature (12 degrees C), relative humidity (95 +/- 2%), and atmosphere showed similar ripening characteristics. The evolutions of metabolite concentrations were studied during ripening. The volatile components were extracted by dynamic headspace extraction, separated and quantified by gas chromatography and identified by mass spectrometry. For each cheese the volatile concentrations varied with the part considered (rind or core). Except for ethyl acetate and 2-pentanone, the volatile quantities observed were higher than their perception thresholds. The flavour component production was best correlated with the starter strains. During the first 10 days the ester formations (ethyl, butyl and isoamyl acetates) were associated with the concentrations of K. lactis and G. candidum. The rind quantity of esters was lower than that observed in core probably due to (1) a diffusion from the core to the surface and (2) evaporation from the surface to the chamber atmosphere. G. candidum and Brev. linens association produced 3 methyl butanol and methyl 3-butanal from leucine, respectively. DMDS came from the methionine catabolism due to Brev. linens. Styrene production was attributed to Pen. camemberti. 2-Pentanone evolution was associated with Pen. camemberti spores and G. candidum. 2-Heptanone changes were not directly related to flora activities while 2-octanone production was essentially due to G. candidum. This study also demonstrates the determining role of volatile component diffusion.

Characterization of Osmotolerant Yeasts and Yeast-Like Molds from Apple Orchards and Apple Juice Processing Plants in China and Investigation of Their Spoilage Potential.

PubMed

Wang, Huxuan; Hu, Zhongqiu; Long, Fangyu; Niu, Chen; Yuan, Yahong; Yue, Tianli

2015-08-01

Yeasts and yeast-like fungal isolates were recovered from apple orchards and apple juice processing plants located in the Shaanxi province of China. The strains were evaluated for osmotolerance by growing them in 50% (w/v) glucose. Of the strains tested, 66 were positive for osmotolerance and were subsequently identified by 26S or 5.8S-ITS ribosomal RNA (rRNA) gene sequencing. Physiological tests and RAPD-PCR analysis were performed to reveal the polymorphism of isolates belonging to the same species. Further, the spoilage potential of the 66 isolates was determining by evaluating their growth in 50% to 70% (w/v) glucose and measuring gas generation in 50% (w/v) glucose. Thirteen osmotolerant isolates representing 9 species were obtained from 10 apple orchards and 53 target isolates representing 19 species were recovered from 2 apple juice processing plants. In total, members of 14 genera and 23 species of osmotolerant isolates including yeast-like molds were recovered from all sources. The commonly recovered osmotolerant isolates belonged to Kluyveromyces marxianus, Hanseniaspora uvarum, Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Candida tropicalis, and Pichia kudriavzevii. The polymorphism of isolates belonging to the same species was limited to 1 to 3 biotypes. The majority of species were capable of growing within a range of glucose concentration, similar to sugar concentrations found in apple juice products with a lag phase from 96 to 192 h. Overall, Z. rouxii was particularly the most tolerant to high glucose concentration with the shortest lag phase of 48 h in 70% (w/v) glucose and the fastest gas generation rate in 50% (w/v) glucose. © 2015 Institute of Food Technologists®

Physicochemical, microbiological and sensory profiles of fermented milk containing probiotic strains isolated from kefir.

PubMed

Kakisu, Emiliano; Irigoyen, Aurora; Torre, Paloma; De Antoni, Graciela L; Abraham, Analía G

2011-11-01

A two-strain starter culture containing Lactobacillus plantarum CIDCA 83114, a potential probiotic strain isolated from kefir grains, and Streptococcus thermophilus CIDCA 321 was tested for the preparation of a fermented milk product. Kluyveromyces marxianus CIDCA 8154, a yeast with immunomodulatory properties was included to formulate a three-strain starter culture. Supernatants of enterohaemorragic Escherichia coli, shiga-toxin-producing strain, along with a two-strain or a three-strain starter culture were included in the medium of Vero-cell surface cultures. The results demonstrated that these combinations of microorganisms antagonize the cytopathic action of shiga toxins. The cell concentration of Lb. plantarum did not decrease during fermentation, indicating that the viability of this strain was not affected by low pH, nor did the number of viable bacteria change during 21 days of storage in either fermented products. The number of viable yeasts increases during fermentation and storage. Trained assessors analyzed the general acceptability of fresh fermented milks and considered both acceptable. The milk fermented with the two-strain starter culture was considered acceptable after two week of storage, while the product fermented with the three-strain starter culture remained acceptable for less than one week. The main changes in sensory attributes detected by the trained panel were in sour taste, milky taste and also in fermented attributes. The correlation between different sensory attributes and acceptability indicated that the panel was positively influenced by milky attributes (taste, odour, and flavour) as well as the intensity of flavour. In conclusion, the two-strain starter culture would be the more promising alternative for inclusion of that potential probiotic lactobacillus in a fermented milk product.

Presence and distribution of yeasts in the reproductive tract in healthy female horses.

PubMed

Azarvandi, A; Khosravi, A R; Shokri, H; Talebkhan Garoussi, M; Gharahgouzlou, F; Vahedi, G; Sharifzadeh, A

2017-09-01

Yeasts are commensal organisms found in the reproductive and gastrointestinal tracts, and on the skin and other mucosa in mammals. The purpose of this study was to isolate and identify yeast flora in the caudal reproductive tract in healthy female horses. Longitudinal study. A total of 453 samples were collected using double-guarded swabs from the vestibule, clitoral fossa and vagina in 151 horses. All samples were cultured on Sabouraud 4% dextrose agar and incubated at 35°C for 7-10 days. Isolates were identified according to their morphological characteristics and biochemical profiles. Yeast colonies were isolated from 60 (39.7%) of the 151 horses. The isolated yeasts belonged to nine genera, and included Candida spp. (53.2%), Cryptococcus spp. (12.2%), Saccharomyces spp. (10.5%), Geotrichum spp. (8.0%), Rhodotorula spp. (7.1%), Malassezia spp. (3.7%), Trichosporon spp. (2.6%), Kluyveromyces spp. (2.6%) and Sporothrix spp. (0.2%). Candida krusei (43.1%) was the most frequent Candida species isolated. There was a significant difference in prevalence between C. krusei and other Candida species (P<0.05). The vestibule contained more yeast isolates (48.0%) than the vagina (18.3%). The isolation of yeast colonies from multiparous females (76.8%) was significantly higher than from maiden mares (P<0.05). The study was limited by the difficulty of distinguishing between normal flora and potential pathogens. Candida spp., in particular C. krusei, represent important flora resident in the caudal reproductive tract in healthy female horses. This is particularly important in contexts that require the initiation of empirical treatment prior to the completion of culture results. © 2016 EVJ Ltd.

Reversible and strong immobilization of proteins by ionic exchange on supports coated with sulfate-dextran.

PubMed

Fuentes, Manuel; Pessela, Benevides C C; Maquiese, Jorgette V; Ortiz, Claudia; Segura, Rosa L; Palomo, Jose M; Abian, Olga; Torres, Rodrigo; Mateo, Cesar; Fernández-Lafuente, Roberto; Guisán, J M

2004-01-01

New and strong ionic exchange resins have been prepared by the simple and rapid ionic adsorption of anionic polymers (sulfate-dextran) on porous supports activated with the opposite ionic group (DEAE/MANAE). Ionic exchange properties of such composites were strongly dependent on the size of the ionic polymers as well as on the conditions of the ionic coating of the solids with the ionic polymers (optimal conditions were 400 mg of sulfate-dextran 5000 kDa per gram of support). Around 80% of the proteins contained in crude extracts from Escherichia coli and Acetobacter turbidans could be adsorbed on these porous composites even at pH 7. This interaction was stronger than that using conventional carboxymethyl cellulose (CMC) and even others such as supports coated with aspartic-dextran polymer. By means of the sequential use of the new supports and supports coated with polyethyleneimine (PEI), all proteins from crude extracts could be immobilized. In fact, a large percentage (over 50%) could be immobilized on both supports. Finally, some industrially relevant enzymes (beta-galactosidases from Aspergillus oryzae, Kluyveromyces lactis, and Thermussp. strain T2, lipases from Candida antarctica A and B, Candida rugosa, Rhizomucor miehei, and Rhyzopus oryzae and bovine pancreas trypsin and chymotrypsin) have been immobilized on these supports with very high activity recoveries and immobilization rates. After enzyme inactivation, the protein could be fully desorbed from the support, and then the support could be reused for several cycles. Moreover, in some instances the enzyme stability was significantly improved, mainly in the presence of organic solvents, perhaps as a consequence of the highly hydrophilic microenvironment of the support.

A genetic overhaul of Saccharomyces cerevisiae 424A(LNH-ST) to improve xylose fermentation.

PubMed

Bera, Aloke K; Ho, Nancy W Y; Khan, Aftab; Sedlak, Miroslav

2011-05-01

Robust microorganisms are necessary for economical bioethanol production. However, such organisms must be able to effectively ferment both hexose and pentose sugars present in lignocellulosic hydrolysate to ethanol. Wild type Saccharomyces cerevisiae can rapidly ferment hexose, but cannot ferment pentose sugars. Considerable efforts were made to genetically engineer S. cerevisiae to ferment xylose. Our genetically engineered S cerevisiae yeast, 424A(LNH-ST), expresses NADPH/NADH xylose reductase (XR) that prefer NADPH and NAD(+)-dependent xylitol dehydrogenase (XD) from Pichia stipitis, and overexpresses endogenous xylulokinase (XK). This strain is able to ferment glucose and xylose, as well as other hexose sugars, to ethanol. However, the preference for different cofactors by XR and XD might lead to redox imbalance, xylitol excretion, and thus might reduce ethanol yield and productivity. In the present study, genes responsible for the conversion of xylose to xylulose with different cofactor specificity (1) XR from N. crassa (NADPH-dependent) and C. parapsilosis (NADH-dependent), and (2) mutant XD from P. stipitis (containing three mutations D207A/I208R/F209S) were overexpressed in wild type yeast. To increase the NADPH pool, the fungal GAPDH enzyme from Kluyveromyces lactis was overexpressed in the 424A(LNH-ST) strain. Four pentose phosphate pathway (PPP) genes, TKL1, TAL1, RKI1 and RPE1 from S. cerevisiae, were also overexpressed in 424A(LNH-ST). Overexpression of GAPDH lowered xylitol production by more than 40%. However, other strains carrying different combinations of XR and XD, as well as new strains containing the overexpressed PPP genes, did not yield any significant improvement in xylose fermentation.

A new search for thermotolerant yeasts, its characterization and optimization using response surface methodology for ethanol production.

PubMed

Arora, Richa; Behera, Shuvashish; Sharma, Nilesh K; Kumar, Sachin

2015-01-01

The progressive rise in energy crisis followed by green house gas (GHG) emissions is serving as the driving force for bioethanol production from renewable resources. Current bioethanol research focuses on lignocellulosic feedstocks as these are abundantly available, renewable, sustainable and exhibit no competition between the crops for food and fuel. However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc. Therefore, the present study was carried out with the objective of isolating hexose and pentose fermenting thermophilic/thermotolerant ethanologens with acceptable product yield. Two thermotolerant isolates, NIRE-K1 and NIRE-K3 were screened for fermenting both glucose and xylose and identified as Kluyveromyces marxianus NIRE-K1 and K. marxianus NIRE-K3. After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3. Further, batch fermentations were carried out under optimized conditions, where K. marxianus NIRE-K3 was found to be superior over K. marxianus NIRE-K1. Ethanol yield (Y x∕s ), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Q p ) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively. This study revealed the promising potential of both the screened thermotolerant isolates for bioethanol production.

A new search for thermotolerant yeasts, its characterization and optimization using response surface methodology for ethanol production

PubMed Central

Arora, Richa; Behera, Shuvashish; Sharma, Nilesh K.; Kumar, Sachin

2015-01-01

The progressive rise in energy crisis followed by green house gas (GHG) emissions is serving as the driving force for bioethanol production from renewable resources. Current bioethanol research focuses on lignocellulosic feedstocks as these are abundantly available, renewable, sustainable and exhibit no competition between the crops for food and fuel. However, the technologies in use have some drawbacks including incapability of pentose fermentation, reduced tolerance to products formed, costly processes, etc. Therefore, the present study was carried out with the objective of isolating hexose and pentose fermenting thermophilic/thermotolerant ethanologens with acceptable product yield. Two thermotolerant isolates, NIRE-K1 and NIRE-K3 were screened for fermenting both glucose and xylose and identified as Kluyveromyces marxianus NIRE-K1 and K. marxianus NIRE-K3. After optimization using Face-centered Central Composite Design (FCCD), the growth parameters like temperature and pH were found to be 45.17°C and 5.49, respectively for K. marxianus NIRE-K1 and 45.41°C and 5.24, respectively for K. marxianus NIRE-K3. Further, batch fermentations were carried out under optimized conditions, where K. marxianus NIRE-K3 was found to be superior over K. marxianus NIRE-K1. Ethanol yield (Yx∕s), sugar to ethanol conversion rate (%), microbial biomass concentration (X) and volumetric product productivity (Qp) obtained by K. marxianus NIRE-K3 were found to be 9.3, 9.55, 14.63, and 31.94% higher than that of K. marxianus NIRE-K1, respectively. This study revealed the promising potential of both the screened thermotolerant isolates for bioethanol production. PMID:26388844

Protein kinase Ymr291w/Tda1 is essential for glucose signaling in saccharomyces cerevisiae on the level of hexokinase isoenzyme ScHxk2 phosphorylation*.

PubMed

Kaps, Sonja; Kettner, Karina; Migotti, Rebekka; Kanashova, Tamara; Krause, Udo; Rödel, Gerhard; Dittmar, Gunnar; Kriegel, Thomas M

2015-03-06

The enzyme ScHxk2 of Saccharomyces cerevisiae is a dual-function hexokinase that besides its catalytic role in glycolysis is involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by the phosphorylation of the nuclear fraction of ScHxk2 at serine 15 and the translocation of the phosphoenzyme into the cytosol. Different studies suggest different serine/threonine protein kinases, Ymr291w/Tda1 or Snf1, to accomplish ScHxk2-S15 phosphorylation. The current paper provides evidence that Ymr291w/Tda1 is essential for that modification, whereas protein kinases Ydr477w/Snf1, Ynl307c/Mck1, Yfr014c/Cmk1, and Ykl126w/Ypk1, which are co-purified during Ymr291w/Tda1 tandem affinity purification, as well as protein kinase PKA and PKB homolog Sch9 are dispensable. Taking into account the detection of a significantly higher amount of the Ymr291w/Tda1 protein in cells grown in low-glucose media as compared with a high-glucose environment, Ymr291w/Tda1 is likely to contribute to glucose signaling in S. cerevisiae on the level of ScHxk2-S15 phosphorylation in a situation of limited external glucose availability. The evolutionary conservation of amino acid residue serine 15 in yeast hexokinases and its phosphorylation is illustrated by the finding that YMR291W/TDA1 of S. cerevisiae and the homologous KLLA0A09713 gene of Kluyveromyces lactis allow for cross-complementation of the respective protein kinase single-gene deletion strains. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Manufacture of a beverage from cheese whey using a "tea fungus" fermentation.

PubMed

Belloso-Morales, Genette; Hernández-Sánchez, Humberto

2003-01-01

Kombucha is a sour beverage reported to have potential health effects prepared from the fermentation of black tea and sugar with a "tea fungus", a symbiotic culture of acetic acid bacteria and yeasts. Although black tea is the preferred substrate for Kombucha fermentation, other beverages have also been tested as substrates with fair results. Cheese whey is a by-product with a good amount of fermentable lactose that has been used before in the production of beverages, so the objective of this study was to test three types of whey (fresh sweet, fresh acid and reconstituted sweet) in the elaboration of a fermented beverage using a kombucha culture as inoculum. The isolation and identification of bacteria and yeasts from the fermented tea and wheys was done along with the study of the rates of change in sugar consumption, acid production and pH decrease. Several species of acetic acid bacteria (Acetobacter aceti subsp. aceti, Gluconobacter oxydans subsp. industrius, subsp. oxydans and Gluconoacetobacter xylinus) were isolated from the different kombuchas along with the yeasts Saccharomyces cerevisiae, Kluyveromyces marxianus, and Brettanomyces bruxelensis. The main metabolic products in the fermented wheys included ethanol, lactic and acetic acids. A good growth was obtained in both sweet wheys in which a pH of 3.3 and a total acid content (mainly lactic and acetic acids) of 0.07 mol/l was reached after 96 h. The sweet whey fermented beverages contained a relatively low lactose concentration (< 12 g/l). The final ethanol content was low (5 g/l) in all the fermented wheys. The whey products were strongly sour and salty non sparkling beverages.

A CTG Clade Candida Yeast Genetically Engineered for the Genotype-Phenotype Characterization of Azole Antifungal Resistance in Human-Pathogenic Yeasts.

PubMed

Accoceberry, Isabelle; Rougeron, Amandine; Biteau, Nicolas; Chevrel, Pauline; Fitton-Ouhabi, Valérie; Noël, Thierry

2018-01-01

A strain of the opportunistic pathogenic yeast Candida lusitaniae was genetically modified for use as a cellular model for assessing by allele replacement the impact of lanosterol C14α-demethylase ERG11 mutations on azole resistance. Candida lusitaniae was chosen because it is susceptible to azole antifungals, it belongs to the CTG clade of yeast, which includes most of the Candida species pathogenic for humans, and it is haploid and easily amenable to genetic transformation and molecular modeling. In this work, allelic replacement is targeted at the ERG11 locus by the reconstitution of a functional auxotrophic marker in the 3' intergenic region of ERG11 Homologous and heterologous ERG11 alleles are expressed from the resident ERG11 promoter of C. lusitaniae , allowing accurate comparison of the phenotypic change in azole susceptibility. As a proof of concept, we successfully expressed in C. lusitaniae different ERG11 alleles, either bearing or not bearing mutations retrieved from a clinical context, from two phylogenetically distant yeasts, C. albicans and Kluyveromyces marxianus Candida lusitaniae constitutes a high-fidelity expression system, giving specific Erg11p-dependent fluconazole MICs very close to those observed with the ERG11 donor strain. This work led us to characterize the phenotypic effect of two kinds of mutation: mutation conferring decreased fluconazole susceptibility in a species-specific manner and mutation conferring fluconazole resistance in several yeast species. In particular, a missense mutation affecting amino acid K143 of Erg11p in Candida species, and the equivalent position K151 in K. marxianus , plays a critical role in fluconazole resistance. Copyright © 2017 American Society for Microbiology.

Patterns of coral disease across the Hawaiian Archipelago: Relating disease to environment

USGS Publications Warehouse

Aeby, G.S.; Williams, G.J.; Franklin, E.C.; Kenyon, J.; Cox, E.F.; Coles, S.; Work, Thierry M.

2011-01-01

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing

Patterns of Coral Disease across the Hawaiian Archipelago: Relating Disease to Environment

PubMed Central

Aeby, Greta S.; Williams, Gareth J.; Franklin, Erik C.; Kenyon, Jean; Cox, Evelyn F.; Coles, Steve; Work, Thierry M.

2011-01-01

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing

Evaluation of six nucleic acid amplification tests used for diagnosis of Neisseria gonorrhoeae in Russia compared with an international strictly validated real-time porA pseudogene polymerase chain reaction.

PubMed

Shipitsyna, E; Zolotoverkhaya, E; Hjelmevoll, S O; Maximova, A; Savicheva, A; Sokolovsky, E; Skogen, V; Domeika, M; Unemo, M

2009-11-01

In Russia, laboratory diagnosis of gonorrhoea has been mainly based on microscopy only and, in some settings, relatively rare suboptimal culturing. In recent years, Russian developed and manufactured nucleic acid amplification tests (NAAT) have been implemented for routine diagnosis of Neisseria gonorrhoeae. However, these NAATs have never been validated to any international well-recognized diagnostic NAAT. This study aims to evaluate the performance characteristics of six Russian NAATs for N. gonorrhoeae diagnostics. In total, 496 symptomatic patients were included. Five polymerase chain reaction (PCR) assays and one real-time nucleic acid sequence based amplification (NASBA) assay, developed by three Russian companies, were evaluated on urogenital samples, i.e. cervical and first voided urine (FVU) samples from females (n = 319), urethral and FVU samples from males (n = 127), and extragenital samples, i.e. rectal and pharyngeal samples, from 50 additional female patients with suspicion of gonorrhoea. As reference method, an international strictly validated real-time porA pseudogene PCR was applied. The prevalence of N. gonorrhoeae was 2.7% and 16% among the patients providing urogenital and extragenital samples, respectively. The Russian NAATs and the reference method displayed high level of concordance (99.4-100%). The sensitivities, specificities, positive predictive values and negative predictive values of the Russian tests in different specimens were 66.7-100%, 100%, 100%, and 99.4-100%, respectively. Russian N. gonorrhoeae diagnostic NAATs comprise relatively good performance characteristics. However, larger studies are crucial and, beneficially, the Russian assays should also be evaluated to other international highly sensitive and specific, and ideally Food and Drug Administration approved, NAATs such as Aptima Combo 2 (Gen-Probe).

Alerta De Insecto-Escarabajo asiatico de antenoas largas

Treesearch

Marco A. Fonseca; Ronald F. Billings

Hay probablemente una sola generacion de ALB por a'o. Los escarabajos adultos por lo general estan presentes de mayo a octubre, pero se pueden encontrar mas temprano en la primavera o mas tarde en el oto?o si las temperaturas son calidas. Los adultos por lo general permanecen en el arbol del que emergieron o se pueden desplazar por distancias cortas hacia un...

Geographical variation of overweight, obesity and related risk factors: Findings from the European Health Examination Survey in Luxembourg, 2013-2015.

PubMed

Samouda, Hanen; Ruiz-Castell, Maria; Bocquet, Valery; Kuemmerle, Andrea; Chioti, Anna; Dadoun, Frédéric; Kandala, Ngianga-Bakwin; Stranges, Saverio

2018-01-01

The analyses of geographic variations in the prevalence of major chronic conditions, such as overweight and obesity, are an important public health tool to identify "hot spots" and inform allocation of funding for policy and health promotion campaigns, yet rarely performed. Here we aimed at exploring, for the first time in Luxembourg, potential geographic patterns in overweight/obesity prevalence in the country, adjusted for several demographic, socioeconomic, behavioural and health status characteristics. Data came from 720 men and 764 women, 25-64 years old, who participated in the European Health Examination Survey in Luxembourg (2013-2015). To investigate the geographical variation, geo-additive semi-parametric mixed model and Bayesian modelisations based on Markov Chain Monte Carlo techniques for inference were performed. Large disparities in the prevalence of overweight and obesity were found between municipalities, with the highest rates of obesity found in 3 municipalities located in the South-West of the country. Bayesian approach also underlined a nonlinear effect of age on overweight and obesity in both genders (significant in men) and highlighted the following risk factors: 1. country of birth for overweight in men born in a non-European country (Posterior Odds Ratio (POR): 3.24 [1.61-8.69]) and women born in Portugal (POR: 2.44 [1.25-4.43]), 2. low educational level (secondary or below) for overweight (POR: 1.66 (1.06-2.72)] and obesity (POR:2.09 [1.05-3.65]) in men, 3. single marital status for obesity in women (POR: 2.20 [1.24-3.91]), 4.fair (men: POR: 3.19 [1.58-6.79], women: POR: 2.24 [1.33-3.73]) to very bad health perception (men: POR: 15.01 [2.16-98.09]) for obesity, 5. sleeping more than 6 hours for obesity in unemployed men (POR: 3.66 [2.02-8.03]). Protective factors highlighted were: 1. single marital status against overweight (POR: [0.60 (0.38-0.96)]) and obesity (POR: 0.39 [0.16-0.84]) in men, 2. the fact to be widowed against overweight in

The Understanding of Astronomy Concepts by Students from Basic Education of a Public School. (Spanish Title: El Entendimiento de Conceptos de Aastronmía Por Los Alumnos de Educación Básica en Una Escuela Pública.) O Entendimento de Conceitos de Astronomia Por Alunos da Educação Básica: O Caso de Uma Escola Pública Brasileira

NASA Astrophysics Data System (ADS)

Iria Machado, Daniel; dos Santos, Carlos

2011-07-01

We present the results obtained in a research on the comprehension of basic astronomical concepts, in which 561 students from fifth grade middle school to third grade high school of a public school of the city of Foz do Iguaçu (Brazil) took part. A test with 20 multiple-choice questions was applied to indentify the most common conceptions expressed by the students. This test was elaborated based on the literature about misconceptions and covered the following topics: the day-night cycle; the time zones; the seasons of the year; the phases of the Moon; the movement of the Moon; the apparent movement of the Sun in the celestial sphere; the eclipses; the dimensions and distances in the Universe; the brightness of the stars and its observation from Earth. Though a small progress was verified in the proportion of scientifically acceptable answers when comparing the eighth grade of middle school to the fifth, and the third grade of high school to the first, there was an overall predominance of alternative conceptions regarding most of the explored subjects, which persisted up to the last year of secondary school. The comparison to data found in this research made in other socio-cultural contexts revealed, in many aspects, similar notions and difficulties revealed by the students. Se presentan los resultados de una investigación sobre la comprensión de conceptos astronómicos básicos, en la cual participaron 561 estudiantes que cursaban entre el quinto grado de la enseñanza primaria y el tercer año de la enseñanza secundaria de una escuela pública de la ciudad de Foz do Iguaçu (Brasil). Se utilizó un test de 20 preguntas de opción múltiple para identificar las concepciones más comunes expresadas por los estudiantes. Este instrumento de recolección de datos se desarrolló en base a la literatura sobre las concepciones alternativas y trató los siguientes temas: el ciclo día-noche, los husos horarios, las estaciones del año, las fases de la Luna, el

Eficacia de la detección sistemática de la gripe en las fronteras en los viajeros que llegan por vía aérea*

PubMed Central

Priest, Patricia C.; Jennings, Lance C.; Duncan, Alasdair R.; Brunton, Cheryl R.; Baker, Michael G.

2015-01-01

Objetivos. Se midieron los síntomas y la prevalencia de la gripe (también llamada influenza), así como la eficacia del mecanismo de detección sistemática basado en los síntomas y la temperatura para diagnosticar la gripe en viajeros internacionales que llegaban por vía aérea. Métodos. El presente estudio transversal recopiló datos de viajeros que llegaron al aeropuerto internacional de Christchurch (Nueva Zelandia) en el invierno del 2008 mediante un cuestionario de salud, medición de la temperatura y toma de muestras de las vías respiratorias. Resultados. De los viajeros, 15 976 (68%) entregaron los formularios completos. De ellos, 17% notificaron al menos un síntoma de gripe; los síntomas más comunes fueron rinorrea o congestión nasal (10%) y tos (8%). Se tomaron muestras de las vías respiratorias de 3 769 viajeros. La prevalencia estimada de la gripe fue de 1,1% (4% en las personas sintomáticas, 0,2% en las asintomáticas). La sensibilidad de los criterios de detección varió de 84% para “cualquier síntoma” a 3% para la fiebre de 37,8 °C o mayor. El valor predictivo positivo fue bajo para todos los criterios. Conclusiones. El método de detección sistemática en las fronteras mediante la autonotificación de síntomas y la toma de la temperatura presenta limitaciones para impedir que una gripe pandémica entre en un país. Basarse en criterios como “cualquier síntoma” o la tos haría que se investigara a varias personas no infectadas, mientras que algunas personas infectadas pasarían inadvertidas. Si se usaran criterios más específicos como la fiebre, la mayoría de las personas infectadas entrarían en el país a pesar del mecanismo de detección.

Risk factors associated with human Rift Valley fever infection: systematic review and meta-analysis.

PubMed

Nicholas, Dennis E; Jacobsen, Kathryn H; Waters, Nigel M

2014-12-01

To identify risk factors for human Rift Valley fever virus (RVFV) infection. A systematic review identified 17 articles reporting on 16 studies examining risk factors for RVFV. Pooled odds ratios (pOR) were calculated for exposures examined in four or more studies. Being male [pOR = 1.4 (1.0, 1.8)], contact with aborted animal tissue [pOR = 3.4 (1.6, 7.3)], birthing an animal [pOR = 3.2 (2.4, 4.2)], skinning an animal [pOR = 2.5 (1.9, 3.2)], slaughtering an animal [pOR = 2.4 (1.4, 4.1)] and drinking raw milk [pOR = 1.8 (1.2, 2.6)] were significantly associated with RVF infection after meta-analysis. Other potential risk factors include sheltering animals in the home and milking an animal, which may both involve contact with animal body fluids. Based on the identified risk factors, use of personal protective equipment and disinfectants by animal handlers may help reduce RVFV transmission during outbreaks. Milk pasteurisation and other possible preventive methods require further investigation. © 2014 John Wiley & Sons Ltd.

Camina por Salud: Walking in Mexican-American Women

PubMed Central

Keller, Colleen S.; Gonzales, Adelita

2008-01-01

Forty-six percent of older Mexican-American women report no leisure time physical activity (PA); 38.1% are obese. This study (1) evaluated a PA intervention on reduction of risk for coronary heart disease (CHD) and (2) determined which variables affected adherence to PA. For 36 weeks, Group I walked 3 days/week; Group II walked 5 days/week. The investigators measured total body fat, regional fat, blood lipids, and adherence to PA The walking interventions favorably affected body fat, with significant differences in body mass index (BMI) reductions[F (2, 16) = 12.86, p = .001]. No statistical differences were noted in the anthropometric and blood lipid results from baseline to the 36-week measures. PMID:18457751

Desigualdad social y tendencias de mortalidad por diabetes.

PubMed

Medina-Gómez, Oswaldo; Medina-Reyes, E Ismael Seth

2017-01-01

To identify the trend of national diabetes mortality by level of marginality at the state and municipal levels. A descriptive study was conducted with records of deaths from diabetes in over 20 years from 1990 to 2013. The national mortality rate was calculated standardized by age according to the 2000 world population and the state level 2013 saw the projected naational population by join point analysis for trend analysis was performed. For the general population, the annual percentage change between 1990 and 1996 was 2.2, from 1996 to 2005 was 4.3, and from 2005 to 2013 was 0.1. The largest increase among women occurred between 1998 and 2005 while among men occurred between 1995 and 2006. At the state level was found higher annual percentage change between the towns with the highest degree of marginalization. The mortality of diabetes in women shows a significant decrease since 2004, among men, the mortality with a continuous upward trend, consistent with the trend that the disease has had in recent years. Copyright: © 2017 SecretarÍa de Salud

Disaster-related exposures and health effects among US Coast Guard responders to Hurricanes Katrina and Rita: a cross-sectional study.

PubMed

Rusiecki, Jennifer A; Thomas, Dana L; Chen, Ligong; Funk, Renée; McKibben, Jodi; Dayton, Melburn R

2014-08-01

Disaster responders work among poorly characterized physical and psychological hazards with little understood regarding health consequences of their work. A survey administered to 2834 US Coast Guard responders to Hurricanes Katrina and Rita provided data on exposures and health effects. Prevalence odds ratios (PORs) evaluated associations between baseline characteristics, missions, exposures, and health effects. Most frequent exposures were animal/insect vector (n = 1309; 46%) and floodwater (n = 817; 29%). Most frequent health effects were sunburn (n = 1119; 39%) and heat stress (n = 810; 30%). Significant positive associations were for mold exposure and sinus infection (POR = 10.39); carbon monoxide and confusion (POR = 6.27); lack of sleep and slips, trips, falls (POR = 3.34) and depression (POR = 3.01); being a Gulf-state responder and depression (POR = 3.22). Increasing protection for disaster responders requires provisions for adequate sleep, personal protective equipment, and access to medical and psychological support.

Making the invisible visible: improved electrospray ion formation of metalloporphyrins/-phthalocyanines by attachment of the formate anion (HCOO(-)).

PubMed

Hitzenberger, Jakob Felix; Dammann, Claudia; Lang, Nina; Lungerich, Dominik; García-Iglesias, Miguel; Bottari, Giovanni; Torres, Tomás; Jux, Norbert; Drewello, Thomas

2016-02-21

A protocol is developed for the coordination of the formate anion (HCOO(-)) to neutral metalloporphyrins (Pors) and -phthalocyanines (Pcs) containing divalent metals as a means to improve their ion formation in electrospray ionization (ESI). This method is particularly useful when the oxidation of the neutral metallomacrocycle fails. While focusing on Zn(II)Pors and Zn(II)Pcs, we show that formate is also readily attached to Mn(II), Mg(II) and Co(II)Pcs. However, for the Co(II)Pc secondary reactions can be observed. Upon collision-induced dissociation (CID), Zn(II)Por/Pc·formate supramolecular complexes can undergo the loss of CO2 in combination with transfer of a hydride anion (H(-)) to the zinc metal center. Further dissociation leads to electron transfer and hydrogen atom loss, generating a route to the radical anion of the Zn(II)Por/Pc without the need for electrochemical reduction, although the Zn(II)Por/Pc may have a too low electron affinity to allow electron transfer directly from the formate anion. In addition to single Por molecules, multi Por arrays were successfully analyzed by this method. In this case, multiple addition of formate occurs, giving rise to multiply charged species. In these multi Por arrays, complexation of the formate anion occurs by two surrounding Por units (sandwich). Therefore, the maximum attainment of formate anions in these arrays corresponds to the number of such sandwich complexes rather than the number of porphyrin moieties. The same bonding motif leads to dimers of the composition [(Zn(II)Por/Pc)2·HCOO](-). In these, the formate anion can act as a structural probe, allowing the distinction of isomeric ions with the formate bridging two macrocycles or being attached to a dimer of directly connected macrocycles.

Fecal Calprotectin Levels Are Closely Correlated with the Absence of Relevant Mucosal Lesions in Postoperative Crohn's Disease.

PubMed

Garcia-Planella, Esther; Mañosa, Míriam; Cabré, Eduard; Marín, Laura; Gordillo, Jordi; Zabana, Yamile; Boix, Jaume; Sáinz, Sergio; Domènech, Eugeni

2016-12-01

Fecal calprotectin (FC) is the best noninvasive biomarker of disease activity in inflammatory bowel disease. Its correlation with endoscopic mucosal lesions could save inconvenient, expensive, and repeated endoscopic examinations in particular clinical settings. To assess the correlation between FC and the existence and severity of endoscopic postoperative recurrence (POR), a group of clinically stable outpatients with Crohn's disease for whom an ileocolonoscopy was routinely planned to assess POR were invited to collect a stool sample before starting bowel cleansing to measure FC. POR was graded by means of Rutgeerts endoscopic score. One hundred nineteen ileocolonoscopies were included, 42% with endoscopic POR. FC was significantly lower in the absence of endoscopic POR and in the absence of any endoscopic lesion. The area under the receiver operating characteristic curve was 0.76 (95% confidence interval, 0.68-0.85) for the diagnosis of the absence of lesions and 0.75 (95% confidence interval, 0.66-0.84) for endoscopic POR. Better sensitivity and negative predictive value were observed when combining FC and serum C-reactive protein (CRP), leading to a sensitivity of 82%, a specificity of 53%, and negative and positive predictive values of 81% and 54%, respectively, for the prediction of endoscopic POR with a combination of FC 100 μg/g and CRP 5 mg/L cutoff values. FC correlates closely with endoscopic POR in clinically stable postoperative patients with Crohn's disease and, when used in combination with CRP, might save endoscopic examinations and allow for a high-grade suspicion of endoscopic POR in the long-term monitoring of these patients.

Anti-inflammatory, Analgesic and Antiulcer properties of Porphyra vietnamensis.

PubMed

Bhatia, Saurabh; Sharma, Kiran; Sharma, Ajay; Nagpal, Kalpana; Bera, Tanmoy

2015-01-01

Aim of the present work was to investigate the anti-inflammatory, analgesic and antiulcer effects of red seaweed Porphyra vietnamensis (P. vietnamenis). Aqueous (POR) and alcoholic (PE) fractions were successfully isolated from P. vietnamenis. Further biological investigations were performed using a classic test of paw edema induced by carrageenan, writhing induced by acetic acid, hot plate method and naproxen induced gastro-duodenal ulcer. Among the fractions POR showed better activity. POR and PE significantly (p < 0.05) reduced carrageenan induced paw edema in a dose dependent manner. In the writhing test POR significantly (p < 0.05) reduced abdominal writhes than PE. In hot plate method POR showed better analgesic activity than PE. POR showed comparable ulcers reducing potential (p<0.01) to that of omeprazole, and has more ulcer reducing potential then PE. The results of this study demonstrated that P. vietnamenis aqueous fraction possesses biological activity that is close to the standards taken for the treatment of peripheral painful or/and inflammatory and ulcer conditions.

Isolation, characterization and cloning of a cDNA encoding a new antifungal defensin from Phaseolus vulgaris L. seeds.

PubMed

Games, Patrícia D; Dos Santos, Izabela S; Mello, Erica O; Diz, Mariângela S S; Carvalho, André O; de Souza-Filho, Gonçalo A; Da Cunha, Maura; Vasconcelos, Ilka M; Ferreira, Beatriz Dos S; Gomes, Valdirene M

2008-12-01

The PvD1 defensin was purified from Phaseolus vulgaris (cv. Pérola) seeds, basically as described by Terras et al. [Terras FRG, Schoofs HME, De Bolle MFC, Van Leuven F, Ress SB, Vanderleyden J, Cammue BPA, Broekaer TWF. Analysis of two novel classes of plant antifungal proteins from radish (Raphanus sativus L.) seeds. J Biol Chem 1992;267(22):15301-9], with some modifications. A DEAE-Sepharose, equilibrated with 20mM Tris-HCl, pH 8.0, was initially utilized for the separation of peptides after ammonium sulfate fractionation. The basic fraction (the non-retained peak) obtained showed the presence of one unique band in SDS-Tricine gel electrophoresis with a molecular mass of approximately 6kDa. The purification of this peptide was confirmed after a reverse-phase chromatography in a C2/C18 column by HPLC, where once again only one peak was observed and denominated H1. H1 was submitted to N-terminal sequencing and the comparative analysis in databanks revealed high similarity with sequences of different defensins isolated from other plants species. The N-terminal sequence of the mature defensin isolated was used to produce a degenerated primer. This primer allowed the amplification of the defensin cDNA by RT-PCR from mRNA of P. vulgaris seeds. The sequence analysis of the cloned cDNA, named PVD1, demonstrated 314bp encoding a polypeptide of 47 amino acids. The deduced peptide presented high similarity with plant defensins of Vigna unguiculata (93%), Cicer arietinum (95%) and Pachyrhizus erosus (87%). PvD1 inhibited the growth of the yeasts, Candida albicans, Candida parapsilosis, Candida tropicalis, Candida guilliermondii, Kluyveromyces marxiannus and Saccharomyces cerevisiae. PvD1 also presented an inhibitory activity against the growth of phytopathogenic fungi including Fusarium oxysporum, Fusarium solani, Fusarium lateritium and Rizoctonia solani.

Taggiasca extra virgin olive oil colonization by yeasts during the extraction process.

PubMed

Ciafardini, G; Cioccia, G; Zullo, B A

2017-04-01

The opalescent appearance of the newly produced olive oil is due to the presence of solid particles and microdrops of vegetation water in which the microorganisms from the olives' carposphere are trapped. Present research has demonstrated that the microbiota of the fresh extracted olive oil, produced in the mills, is mainly composed of yeasts and to a lesser extent of molds. The close link between the composition of the microbiota of the olives' carposphere undergoing to processing, and that of the microbiota of the newly produced olive oil, concerns only the yeasts and molds, given that the bacterial component is by and large destroyed mainly in the kneaded paste during the malaxation process. Six physiologically homogenous yeast groups were highlighted in the wash water, kneaded paste and newly produced olive oil from the Taggiasca variety which had been collected in mills located in the Liguria region. The more predominant yeasts of each group belonged to a single species called respectively: Kluyveromyces marxianus, Candida oleophila, Candida diddensiae, Candida norvegica, Wickerhamomyces anomalus and Debaryomyces hansenii. Apart from K. marxianus, which was found only in the wash water, all the other species were found in the wash water and in the kneaded paste as well as in the newly produced olive oil, while in the six-month stored olive oil, was found only one physiologically homogeneous group of yeast represented by the W. anomalus specie. These findings in according to our previous studies carried out on other types of mono varietal olive oils, confirms that the habitat of the Taggiascas' extra virgin olive oil, had a strong selective pressure on the yeast biota, allowing only to a few member of yeast species, contaminating the fresh product, to survive and reproduce in it during storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pichia stipitis Genes for Alcohol Dehydrogenase with Fermentative and Respiratory Functions

PubMed Central

Cho, Jae-yong; Jeffries, Thomas W.

1998-01-01

Two genes coding for isozymes of alcohol dehydrogenase (ADH); designated PsADH1 and PsADH2, have been identified and isolated from Pichia stipitis CBS 6054 genomic DNA by Southern hybridization to Saccharomyces cerevisiae ADH genes, and their physiological roles have been characterized through disruption. The amino acid sequences of the PsADH1 and PsADH2 isozymes are 80.5% identical to one another and are 71.9 and 74.7% identical to the S. cerevisiae ADH1 protein. They also show a high level identity with the group I ADH proteins from Kluyveromyces lactis. The PsADH isozymes are presumably localized in the cytoplasm, as they do not possess the amino-terminal extension of mitochondrion-targeted ADHs. Gene disruption studies suggest that PsADH1 plays a major role in xylose fermentation because PsADH1 disruption results in a lower growth rate and profoundly greater accumulation of xylitol. Disruption of PsADH2 does not significantly affect ethanol production or aerobic growth on ethanol as long as PsADH1 is present. The PsADH1 and PsADH2 isozymes appear to be equivalent in the ability to convert ethanol to acetaldehyde, and either is sufficient to allow cell growth on ethanol. However, disruption of both genes blocks growth on ethanol. P. stipitis strains disrupted in either PsADH1 or PsADH2 still accumulate ethanol, although in different amounts, when grown on xylose under oxygen-limited conditions. The PsADH double disruptant, which is unable to grow on ethanol, still produces ethanol from xylose at about 13% of the rate seen in the parental strain. Thus, deletion of both PsADH1 and PsADH2 blocks ethanol respiration but not production, implying a separate path for fermentation. PMID:9546172

The yeasts phosphorelay systems: a comparative view.

PubMed

Salas-Delgado, Griselda; Ongay-Larios, Laura; Kawasaki-Watanabe, Laura; López-Villaseñor, Imelda; Coria, Roberto

2017-06-01

Cells contain signal transduction pathways that mediate communication between the extracellular environment and the cell interior. These pathways control transcriptional programs and posttranscriptional processes that modify cell metabolism in order to maintain homeostasis. One type of these signal transduction systems are the so-called Two Component Systems (TCS), which conduct the transfer of phosphate groups between specific and conserved histidine and aspartate residues present in at least two proteins; the first protein is a sensor kinase which autophosphorylates a histidine residue in response to a stimulus, this phosphate is then transferred to an aspartic residue located in a response regulator protein. There are classical and hybrid TCS, whose difference consists in the number of proteins and functional domains involved in the phosphorelay. The TCS are widespread in bacteria where the sensor and its response regulator are mostly specific for a given stimulus. In eukaryotic organisms such as fungi, slime molds, and plants, TCS are present as hybrid multistep phosphorelays, with a variety of arrangements (Stock et al. in Annu Rev Biochem 69:183-215, 2000; Wuichet et al. in Curr Opin Microbiol 292:1039-1050, 2010). In these multistep phosphorelay systems, several phosphotransfer events take place between different histidine and aspartate residues localized in specific domains present in more than two proteins (Thomason and Kay, in J Cell Sci 113:3141-3150, 2000; Robinson et al. in Nat Struct Biol 7:626-633, 2000). This review presents a brief and succinct description of the Two-component systems of model yeasts, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans, Cryptococcus neoformans and Kluyveromyces lactis. We have focused on the comparison of domain organization and functions of each component present in these phosphorelay systems.

Down-regulation of intestinal epithelial innate response by probiotic yeasts isolated from kefir.

PubMed

Romanin, David; Serradell, María; González Maciel, Dolores; Lausada, Natalia; Garrote, Graciela L; Rumbo, Martín

2010-06-15

Kefir is obtained by milk fermentation with a complex microbial population included in a matrix of polysaccharide and proteins. Several health-promoting activities has been attributed to kefir consumption. The aim of this study was to select microorganisms from kefir able to down-regulate intestinal epithelial innate response and further characterize this activity. Caco-2 cells stably transfected with a human CCL20 promoter luciferase reporter were used to screen a collection of 24 yeast and 23 bacterial strains isolated from kefir. The Toll-like receptor 5 agonist, flagellin was used to activate the reporter cells, while pre-incubation with the selected strains was tested to identify strains with the capacity to inhibit cell activation. In this system, 21 yeast strains from the genera Saccharomyces, Kluyveromyces and Issatchenkia inhibited almost 100% of the flagellin-dependent activation, whereas only some lactobacilli strains showed a partial effect. K. marxianus CIDCA 8154 was selected for further characterization. Inhibitory activity was confirmed at transcriptional level on Caco-2/TC-7 and HT-29 cells upon flagellin stimulation. A similar effect was observed using other pro-inflammatory stimulation such as IL-1beta and TNF-alpha. Pre-incubation with yeasts induced a down-regulation of NF-kappaB signalling in epithelial cells in vitro, as well as expression of other pro-inflammatory chemokines such as CXCL8 and CXCL2. Furthermore, modulation of CCL20 mRNA expression upon flagellin stimulation was evidenced in vivo, in a mouse ligated intestinal loop model. Results indicate kefir contains microorganisms able to abolish the intestinal epithelial inflammatory response that could explain some of the properties attributed to this fermented milk. Copyright 2010 Elsevier B.V. All rights reserved.

Occurrence, horizontal transfer and degeneration of VDE intein family in Saccharomycete yeasts.

PubMed

Okuda, Yoshihiro; Sasaki, Daisuke; Nogami, Satoru; Kaneko, Yoshinobu; Ohya, Yoshikazu; Anraku, Yasuhiro

2003-05-01

VDE is a homing endonuclease gene originally discovered as an intervening element in VMA1s of Saccharomyces cerevisiae. There have been two independent subfamilies of VDE, one from S. cerevisiae strain X2180-1A and the other from Saccharomyces sp. DH1-1A in the host VMA1 gene, and they share the identity of 96.3%. In order to search the occurrence, intra/interspecies transfer and molecular degeneration of VDE, complete sequences of VMA1 in 10 strains of S. cerevisiae, eight species of saccharomycete yeasts, Candida glabrata and Kluyveromyces lactis were determined. We found that six of 10 S. cerevisiae strains contain VDEs 99.7-100% identical to that of the strain X2180-1A, one has no VDE, whereas the other three harbour VDEs 100% identical to that of the strain DH1-1A. S. carlsbergensis has two VMA1s, one being 99.8% identical to that of the strain X2180-1A with VDE 100% identical to that of the strain DH1-1A and the other containing the same VMA1 in S. pastorianus with no VDE. This and other evidence indicates that intra/interspecies transmissions of VDEs have occurred among saccharomycete yeasts. Phylogenetic analyses of VMA1 and VDE suggest that the S. cerevisiae VDEs had branched earlier than other VDEs from an ancestral VDE and had invaded into the host loci as relatively late events. The two VDEs seemed to degenerate in individual host loci, retaining their splicing capacity intact. The degeneration of the endonuclease domains was distinct and, if compared, its apparent rate was much faster than that of the protein-splicing domains. Copyright 2003 John Wiley & Sons, Ltd.

Solution structure of the DNA-binding domain of the heat shock transcription factor determined by multidimensional heteronuclear magnetic resonance spectroscopy.

PubMed Central

Damberger, F. F.; Pelton, J. G.; Harrison, C. J.; Nelson, H. C.; Wemmer, D. E.

1994-01-01

The solution structure of the 92-residue DNA-binding domain of the heat shock transcription factor from Kluyveromyces lactis has been determined using multidimensional NMR methods. Three-dimensional (3D) triple resonance, 1H-13C-13C-1H total correlation spectroscopy, and 15N-separated total correlation spectroscopy-heteronuclear multiple quantum correlation experiments were used along with various 2D spectra to make nearly complete assignments for the backbone and side-chain 1H, 15N, and 13C resonances. Five-hundred eighty-three NOE constraints identified in 3D 13C- and 15N-separated NOE spectroscopy (NOESY)-heteronuclear multiple quantum correlation spectra and a 4-dimensional 13C/13C-edited NOESY spectrum, along with 35 phi, 9 chi 1, and 30 hydrogen bond constraints, were used to calculate 30 structures by hybrid distance geometry/stimulated annealing protocol, of which 24 were used for structural comparison. The calculations revealed that a 3-helix bundle packs against a small 4-stranded antiparallel beta-sheet. The backbone RMS deviation (RMSD) for the family of structures was 1.03 +/- 0.19 A with respect to the average structure. The topology is analogous to that of the C-terminal domain of the catabolite gene activator protein and appears to be in the helix-turn-helix family of DNA-binding proteins. The overall fold determined by the NMR data is consistent with recent crystallographic work on this domain (Harrison CJ, Bohm AA, Nelson HCM, 1994, Science 263:224) as evidenced by RMSD between backbone atoms in the NMR and X-ray structures of 1.77 +/- 0.20 A. Several differences were identified some of which may be due to protein-protein interactions in the crystal. PMID:7849597

Synthesis of the Galactosyl Derivative of Gluconic Acid With the Transglycosylation Activity of β-Galactosidase

PubMed Central

2017-01-01

Summary Bionic acids are bioactive compounds demonstrating numerous interesting properties. They are widely produced by chemical or enzymatic oxidation of disaccharides. This paper focuses on the galactosyl derivative of gluconic acid as a result of a new method of bionic acid synthesis which utilises the transglycosylation properties of β-galactosidase and introduces lactose as a substrate. Products obtained in such a process are characterised by different structures (and, potentially, properties) than those resulting from traditional oxidation of disaccharides. The aim of this study is to determine the effect of selected parameters (concentration and ratio of substrates, dose of the enzyme, time, pH, presence of salts) on the course of the reaction carried out with the enzymatic preparation Lactozym, containing β-galactosidase from Kluyveromyces lactis. Research has shown that increased dry matter content in the baseline solution (up to 50%, by mass per volume) and an addition of NaCl contribute to higher yield. On the other hand, reduced content of the derivative is a result of increased pH from 7.0 to 9.0 and an addition of magnesium and manganese salts. Moreover, exceeding the β-galactosidase dose over approx. 35 000 U per 100 g of lactose also leads to reduced yield of the process. The most favourable molar ratio of sodium gluconate to lactose is 2.225:0.675. Depending on the conditions of the synthesis, the product concentration ranged between 17.3 and 118.3 g/L of the reaction mixture, which corresponded to the mass fraction of 6.64–23.7% of dry matter. The data obtained as a result of the present study may be useful for designing an industrial process. PMID:28867957

The effect of lactic acid bacteria on cocoa bean fermentation.

PubMed

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2015-07-16

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

Sustainable conversion of coffee and other crop wastes to biofuels and bioproducts using coupled biochemical and thermochemical processes in a multi-stage biorefinery concept.

PubMed

Hughes, Stephen R; López-Núñez, Juan Carlos; Jones, Marjorie A; Moser, Bryan R; Cox, Elby J; Lindquist, Mitch; Galindo-Leva, Luz Angela; Riaño-Herrera, Néstor M; Rodriguez-Valencia, Nelson; Gast, Fernando; Cedeño, David L; Tasaki, Ken; Brown, Robert C; Darzins, Al; Brunner, Lane

2014-10-01

The environmental impact of agricultural waste from the processing of food and feed crops is an increasing concern worldwide. Concerted efforts are underway to develop sustainable practices for the disposal of residues from the processing of such crops as coffee, sugarcane, or corn. Coffee is crucial to the economies of many countries because its cultivation, processing, trading, and marketing provide employment for millions of people. In coffee-producing countries, improved technology for treatment of the significant amounts of coffee waste is critical to prevent ecological damage. This mini-review discusses a multi-stage biorefinery concept with the potential to convert waste produced at crop processing operations, such as coffee pulping stations, to valuable biofuels and bioproducts using biochemical and thermochemical conversion technologies. The initial bioconversion stage uses a mutant Kluyveromyces marxianus yeast strain to produce bioethanol from sugars. The resulting sugar-depleted solids (mostly protein) can be used in a second stage by the oleaginous yeast Yarrowia lipolytica to produce bio-based ammonia for fertilizer and are further degraded by Y. lipolytica proteases to peptides and free amino acids for animal feed. The lignocellulosic fraction can be ground and treated to release sugars for fermentation in a third stage by a recombinant cellulosic Saccharomyces cerevisiae, which can also be engineered to express valuable peptide products. The residual protein and lignin solids can be jet cooked and passed to a fourth-stage fermenter where Rhodotorula glutinis converts methane into isoprenoid intermediates. The residues can be combined and transferred into pyrocracking and hydroformylation reactions to convert ammonia, protein, isoprenes, lignins, and oils into renewable gas. Any remaining waste can be thermoconverted to biochar as a humus soil enhancer. The integration of multiple technologies for treatment of coffee waste has the potential to

Spectroscopic study, antimicrobial activity and crystal structures of N-(2-hydroxy-5-nitrobenzalidene)4-aminomorpholine and N-(2-hydroxy-1-naphthylidene)4-aminomorpholine

NASA Astrophysics Data System (ADS)

Yıldız, Mustafa; Ünver, Hüseyin; Dülger, Başaran; Erdener, Diğdem; Ocak, Nazan; Erdönmez, Ahmet; Durlu, Tahsin Nuri

2005-03-01

Schiff bases N-(2-hydroxy-3-nitrobenzalidene)4-aminomorpholine ( 1) and N-(2-hydroxy-1-naphthylidene)4-aminomorpholine ( 2) were synthesized from the reaction of 4-aminomorpholine with 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde. Compounds 1 and 2 were characterized by elemental analysis, IR, 1H NMR, 13C NMR and UV-Visible techniques. The UV-Visible spectra of the Schiff bases with OH group in ortho position to the imino group were studied in polar and nonpolar solvents in acidic and basic media. The structures of compounds 1 and 2 have been examined cyrstallographically, for two compounds exist as dominant form of enol-imines in both the solutions and solid state. The title compounds 1 and 2 crystallize in the monoclinic space group P2 1/ c and P2 1/ n with unit cell parameters: a=8.410(1) and 11.911(3), b=6.350(9) and 4.860(9), c=21.728(3) and 22.381(6) Å, β=90.190(1) and 95.6(2)°, V=1160.6(3) and 1289.5(5) Å 3, Dx=1.438 and 1.320 g cm -3, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares. The antimicrobial activities of compounds 1 and 2 have also been studied. The antimicrobial activities of the ligands have been screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smegmatis CCM 2067, Bacillus cereus ATCC 7064, Listeria monocytogenes ATCC 15313, Candida albicans ATCC 10231, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238 and Hanseniaspora guilliermondii DSM 3432.

76 FR 24857 - Fresh Garlic From the People's Republic of China: Preliminary Intent To Rescind New Shipper Reviews

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-03

... sales are not bona fide. As such, we are preliminarily rescinding the NSR for Shenzhen Bainong and... sale or entry during the original, unextended POR, and therefore we are preliminarily rescinding the...-annual NSR POR. When the sale of the subject merchandise occurs within the POR specified by the...

An ortholog of farA of Aspergillus nidulans is implicated in the transcriptional activation of genes involved in fatty acid utilization in the yeast Yarrowia lipolytica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poopanitpan, Napapol; Kobayashi, Satoshi; Fukuda, Ryouichi

2010-11-26

Research highlights: {yields} POR1 is a Yarrowia lipolytica ortholog of farA involved in fatty acid response in A. nidulans. {yields} Deletion of POR1 caused growth defects on fatty acids. {yields} {Delta}por1 strain exhibited defects in the induction of genes involved in fatty acid utilization. -- Abstract: The yeast Yarrowia lipolytica effectively utilizes hydrophobic substrates such as fatty acids and n-alkanes. To identify a gene(s) regulating fatty acid utilization in Y. lipolytica, we first studied homologous genes to OAF1 and PIP2 of Saccharomyces cerevisiae, but their disruption did not change growth on oleic acid at all. We next characterized a Y.more » lipolytica gene, POR1 (primary oleate regulator 1), an ortholog of farA encoding a transcriptional activator that regulates fatty acid utilization in Aspergillus nidulans. The deletion mutant of POR1 was defective in the growth on various fatty acids, but not on glucose, glycerol, or n-hexadecane. It exhibited slight defect on n-decane. The transcriptional induction of genes involved in {beta}-oxidation and peroxisome proliferation by oleate was distinctly diminished in the {Delta}por1 strains. These data suggest that POR1 encodes a transcriptional activator widely regulating fatty acid metabolism in Y. lipolytica.« less

NADPH–Cytochrome P450 Oxidoreductase: Roles in Physiology, Pharmacology, and Toxicology

PubMed Central

Ding, Xinxin; Wolf, C. Roland; Porter, Todd D.; Pandey, Amit V.; Zhang, Qing-Yu; Gu, Jun; Finn, Robert D.; Ronseaux, Sebastien; McLaughlin, Lesley A.; Henderson, Colin J.; Zou, Ling; Flück, Christa E.

2013-01-01

This is a report on a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the Experimental Biology 2012 meeting in San Diego, California, on April 25, 2012. The symposium speakers summarized and critically evaluated our current understanding of the physiologic, pharmacological, and toxicological roles of NADPH–cytochrome P450 oxidoreductase (POR), a flavoprotein involved in electron transfer to microsomal cytochromes P450 (P450), cytochrome b5, squalene mono-oxygenase, and heme oxygenase. Considerable insight has been derived from the development and characterization of mouse models with conditional Por deletion in particular tissues or partial suppression of POR expression in all tissues. Additional mouse models with global or conditional hepatic deletion of cytochrome b5 are helping to clarify the P450 isoform- and substrate-specific influences of cytochrome b5 on P450 electron transfer and catalytic function. This symposium also considered studies using siRNA to suppress POR expression in a hepatoma cell–culture model to explore the basis of the hepatic lipidosis phenotype observed in mice with conditional deletion of Por in liver. The symposium concluded with a strong translational perspective, relating the basic science of human POR structure and function to the impacts of POR genetic variation on human drug and steroid metabolism. PMID:23086197

Influence of cytochrome P450 oxidoreductase genetic polymorphisms on CYP1A2 activity and inducibility by smoking.

PubMed

Dobrinas, Maria; Cornuz, Jacques; Pedrido, Leticia; Eap, Chin B

2012-02-01

Cytochrome P4501A2 (CYP1A2) presents a high interindividual variability in its activity and also in its inducibility by smoking. Cytochrome P450 oxidoreductase (POR) is an electron transfer protein that catalyzes the activity of several cytochromes P450. We aimed to study the influence of POR genetic polymorphisms on CYP1A2 activity while smoking and after smoking cessation, as well as on CYP1A2 inducibility. CYP1A2 activity was determined by the paraxanthine/caffeine ratio in 184 smokers and in 113 of these smokers who were abstinent during a 4-week period. Participants were genotyped for POR rs17148944G>A, rs10239977C>T, rs3815455C>T, rs2286823G>A, rs2302429G>A, and rs1057868C>T (POR*28) polymorphisms. While smoking, none of the tested POR polymorphisms showed a significant influence on CYP1A2 activity. After smoking cessation, significantly higher CYP1A2 activity was found in POR rs2302429A carriers (P=0.038) and in carriers of rs17148944G-rs10239977C-rs3815455T-rs2286823G-rs2302429A-rs1057868T haplotype (P=0.038), whereas carriers of POR rs2286823A (P=0.031) and of the rs17148944G-rs10239977C-rs3815455C-rs2286823A-rs2302429G-rs1057868C haplotype (P=0.031) had decreased CYP1A2 activity. In the complete regression model, only POR rs2302429G>A showed a significant effect (P=0.017). No influence of POR genotypes or haplotypes was observed on the inducibility of CYP1A2. POR genetic polymorphisms influence CYP1A2 basal but not induced activity and do not seem to influence CYP1A2 inducibility. Future work is warranted to identify other clinical and genetic factors that may explain the variability in CYP1A2 activity and inducibility by smoking.

Deletion of P399{sub E}401 in NADPH cytochrome P450 oxidoreductase results in partial mixed oxidase deficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flueck, Christa E., E-mail: christa.flueck@dkf.unibe.ch; Mallet, Delphine; Hofer, Gaby

2011-09-09

Highlights: {yields} Mutations in human POR cause congenital adrenal hyperplasia. {yields} We are reporting a novel 3 amino acid deletion mutation in POR P399{sub E}401del. {yields} POR mutation P399{sub E}401del decreased P450 activities by 60-85%. {yields} Impairment of steroid metabolism may be caused by multiple hits. {yields} Severity of aromatase inhibition is related to degree of in utero virilization. -- Abstract: P450 oxidoreductase (POR) is the electron donor for all microsomal P450s including steroidogenic enzymes CYP17A1, CYP19A1 and CYP21A2. We found a novel POR mutation P399{sub E}401del in two unrelated Turkish patients with 46,XX disorder of sexual development. Recombinant PORmore » proteins were produced in yeast and tested for their ability to support steroid metabolizing P450 activities. In comparison to wild-type POR, the P399{sub E}401del protein was found to decrease catalytic efficiency of 21-hydroxylation of progesterone by 68%, 17{alpha}-hydroxylation of progesterone by 76%, 17,20-lyase action on 17OH-pregnenolone by 69%, aromatization of androstenedione by 85% and cytochrome c reduction activity by 80%. Protein structure analysis of the three amino acid deletion P399{sub E}401 revealed reduced stability and flexibility of the mutant. In conclusion, P399{sub E}401del is a novel mutation in POR that provides valuable genotype-phenotype and structure-function correlation for mutations in a different region of POR compared to previous studies. Characterization of P399{sub E}401del provides further insight into specificity of different P450s for interaction with POR as well as nature of metabolic disruptions caused by more pronounced effect on specific P450s like CYP17A1 and aromatase.« less

"Spider"-shaped porphyrins with conjugated pyridyl anchoring groups as efficient sensitizers for dye-sensitized solar cells.

PubMed

Stangel, Christina; Bagaki, Anthi; Angaridis, Panagiotis A; Charalambidis, Georgios; Sharma, Ganesh D; Coutsolelos, Athanasios G

2014-11-17

Two novel "spider-shaped" porphyrins, meso-tetraaryl-substituted 1PV-Por and zinc-metalated 1PV-Zn-Por, bearing four oligo(p-phenylenevinylene) (oPPV) pyridyl groups with long dodecyloxy chains on the phenyl groups, have been synthesized. The presence of four pyridyl groups in both porphyrins, which allow them to act as anchoring groups upon coordination to various Lewis acid sites, the conjugated oPPV bridges, which offer the possibility of electronic communication between the porphyrin core and the pyridyl groups, and the dodecyloxy groups, which offer the advantage of high solubility in a variety of organic solvents of different polarities and could prevent porphyrin aggregation, renders porphyrins 1PV-Por and 1PV-Zn-Por very promising sensitizers for dye-sensitized solar cells (DSSCs). Photophysical measurements, together with electrochemistry experiments and density functional theory calculations, suggest that both porphyrins have frontier molecular orbital energy levels that favor electron injection and dye regeneration in DSSCs. Solar cells sensitized by 1PV-Por and 1PV-Zn-Por were fabricated, and it was found that they show power conversion efficiencies (PCEs) of 3.28 and 5.12%, respectively. Photovoltaic measurements (J-V curves) together with incident photon-to-electron conversion efficiency spectra of the two cells reveal that the higher PCE value of the DSSC based on 1PV-Zn-Por is ascribed to higher short-circuit current (Jsc), open-circuit voltage (Voc), and dye loading values. Emission spectra and electrochemistry experiments suggest a greater driving force for injection of the photogenerated electrons into the TiO2 conduction band for 1PV-Zn-Por rather than its free-base analogue. Furthermore, electrochemical impedance spectroscopy measurements prove that the utilization of 1PV-Zn-Por as a sensitizer offers a high charge recombination resistance and, therefore, leads to a longer electron lifetime.

Anti-inflammatory, Analgesic and Antiulcer properties of Porphyra vietnamensis

PubMed Central

Bhatia, Saurabh; Sharma, Kiran; Sharma, Ajay; Nagpal, Kalpana; Bera, Tanmoy

2015-01-01

Objectives: Aim of the present work was to investigate the anti-inflammatory, analgesic and antiulcer effects of red seaweed Porphyra vietnamensis (P. vietnamenis). Materials and Methods: Aqueous (POR) and alcoholic (PE) fractions were successfully isolated from P. vietnamenis. Further biological investigations were performed using a classic test of paw edema induced by carrageenan, writhing induced by acetic acid, hot plate method and naproxen induced gastro-duodenal ulcer. Results: Among the fractions POR showed better activity. POR and PE significantly (p < 0.05) reduced carrageenan induced paw edema in a dose dependent manner. In the writhing test POR significantly (p < 0.05) reduced abdominal writhes than PE. In hot plate method POR showed better analgesic activity than PE. POR showed comparable ulcers reducing potential (p<0.01) to that of omeprazole, and has more ulcer reducing potential then PE. Conclusions: The results of this study demonstrated that P. vietnamenis aqueous fraction possesses biological activity that is close to the standards taken for the treatment of peripheral painful or/and inflammatory and ulcer conditions. PMID:25767759

La Resonancia J/$$\\psi$$ y Sus Implicaciones Para La Masa Del W (in Spanish)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchez-Hernandez, Alberto

Es un placer agradecer a mi asesor el doctor Heriberto Castilla Valdez por brindarme sus conocimientos, experiencia y paciencia en el desarrollo de esta tesis; tambien quiero agradecer al profesor H.E. Fisk, por su apoyo econemico en mi estancia en Fermilab. De igual forma agradezco a los doctores Arturo Fernandez Telles, Miguel Angel Perez Angen y Rebeca Juarez Wisozka quienes me introdujeron al campo de la fisica experimental de altas energfas. Agradezco tambien a Maribel Rios Cruz, Ruben Flores Mendieta, Juan Morales Corona, Fabiola Vazquez Valencia, Salvador Carrillo Moreno y Cecilia Uribe Estrada por su amistad y compaiierismo durante elmore » desarrollo de mi maestria. Un especial agradecimiento a Ian Adam y Kina Denisenko por su valiosa ayuda, comentarios y discusiones durante mi estancia en Fermilab. Por ultimo quisiera agradecer a mis profesores, amigos y familiares quienes siempre me apoyaron y alentaron y al Consejo N acional de Ciencia y Tecnologfa asf como al Departamento de Fisica de Cinvestav por su apoyo econemlco.« less

Influence of the doping type and level on the morphology of porous Si formed by galvanic etching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pyatilova, O. V., E-mail: 5ilova87@gmail.com; Gavrilov, S. A.; Shilyaeva, Yu. I.

The formation of porous silicon (por-Si) layers by the galvanic etching of single-crystal Si samples (doped with boron or phosphorus) in an HF/C{sub 2}H{sub 5}OH/H{sub 2}O{sub 2} solution is investigated. The por-Si layers are analyzed by the capillary condensation of nitrogen and scanning electron microscopy (SEM). The dependences of the morphological characteristics of por-Si (pore diameter, specific surface area, pore volume, and thickness of the pore walls), which determine the por-Si combustion kinetics, on the dopant type and initial wafer resistivity are established.

Evidence for the bacterial origin of genes encoding fermentation enzymes of the amitochondriate protozoan parasite Entamoeba histolytica.

PubMed

Rosenthal, B; Mai, Z; Caplivski, D; Ghosh, S; de la Vega, H; Graf, T; Samuelson, J

1997-06-01

Entamoeba histolytica is an amitochondriate protozoan parasite with numerous bacterium-like fermentation enzymes including the pyruvate:ferredoxin oxidoreductase (POR), ferredoxin (FD), and alcohol dehydrogenase E (ADHE). The goal of this study was to determine whether the genes encoding these cytosolic E. histolytica fermentation enzymes might derive from a bacterium by horizontal transfer, as has previously been suggested for E. histolytica genes encoding heat shock protein 60, nicotinamide nucleotide transhydrogenase, and superoxide dismutase. In this study, the E. histolytica por gene and the adhE gene of a second amitochondriate protozoan parasite, Giardia lamblia, were sequenced, and their phylogenetic positions were estimated in relation to POR, ADHE, and FD cloned from eukaryotic and eubacterial organisms. The E. histolytica por gene encodes a 1,620-amino-acid peptide that contained conserved iron-sulfur- and thiamine pyrophosphate-binding sites. The predicted E. histolytica POR showed fewer positional identities to the POR of G. lamblia (34%) than to the POR of the enterobacterium Klebsiella pneumoniae (49%), the cyanobacterium Anabaena sp. (44%), and the protozoan Trichomonas vaginalis (46%), which targets its POR to anaerobic organelles called hydrogenosomes. Maximum-likelihood, neighbor-joining, and parsimony analyses also suggested as less likely E. histolytica POR sharing more recent common ancestry with G. lamblia POR than with POR of bacteria and the T. vaginalis hydrogenosome. The G. lamblia adhE encodes an 888-amino-acid fusion peptide with an aldehyde dehydrogenase at its amino half and an iron-dependent (class 3) ADH at its carboxy half. The predicted G. lamblia ADHE showed extensive positional identities to ADHE of Escherichia coli (49%), Clostridium acetobutylicum (44%), and E. histolytica (43%) and lesser identities to the class 3 ADH of eubacteria and yeast (19 to 36%). Phylogenetic analyses inferred a closer relationship of the E

First example of a modular porphyrinoid assembly capable of stabilizing different metal ions in a single molecular scaffold.

PubMed

Murugavel, Muthuchamy; Reddy, R V Ramana; Dey, Dhananjay; Sankar, Jeyaraman

2015-10-05

We report the synthesis and characterization of porphyrin-corrole-porphyrin (Por-Cor-Por) hybrids directly linked at the meso-meso positions for the first time. The stability and solubility of the trimer are carefully balanced by adding electron-withdrawing substituents to the corrole ring and sterically bulky groups on the porphyrins. The new hybrids are capable of stabilizing more than one metal ion in a single molecular scaffold. The versatility of the triad has been demonstrated by successfully stabilizing homo- (Ni) and heterotrinuclear (Ni-Cu-Ni) coordination motifs. The solid-state structure of the NiPor-CuCor-PorNi hybrid was revealed by single-crystal X-ray diffraction studies. The Ni(II) porphyrins are significantly ruffled and tilted by 83° from the plane of corrole. The robustness of the synthesized hybrids was reflected in the electrochemical investigations and the redox behaviour of the hybrids show that the oxidation processes are mostly corrole-centred. In particular it is worth noting that the Por-Cor-Por hybrid can further be manipulated due to the presence of substituent-free meso-positions on both the terminals. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Management of post-operative Crohn's disease in 2017: where do we go from here?

PubMed

Nguyen, Vu; Kanth, Rajan; Gazo, Joshua; Sorrentino, Dario

2016-11-01

Postoperative recurrence (POR) of Crohn's disease is common after surgical resection. How to best manage POR remains uncertain. Areas covered: In this review, we will first describe the natural course and the best modalities to diagnose this surgical sequela. We will then focus on the potential risk factors for relapse and highlight the main shortcomings in the current study designs and endoscopic and clinical scoring systems, which may partly explain the unexpected outcomes of recent clinical trials. Finally, we will propose a strategy to address the management of POR. Expert commentary: Anti-tumor necrosis factor (Anti-TNF) agents are the most effective therapy to prevent POR in Crohn's disease. Patient risk stratification and active monitoring with scheduled ileocolonoscopy are cornerstones of optimal POR management. Further studies are needed to address areas of uncertainty including timing and duration of therapy and the role of therapeutic drug monitoring in this setting.

Developing a military nurse scientist program of research: A military women's health exemplar.

PubMed

Trego, Lori Lyn

Developing a feasible, fundable, and sustainable program of research (POR) is an essential career goal in research. Nurse scientists can lay the foundation for a salient POR as early as during their doctoral studies. The ensuing years of postdoctoral experiences are informative as they expand their research skills and knowledge around their research area of interest. Following graduation from a doctoral research program, novice military nurse scientists (MNS) are placed in positions that are conducive to fostering a POR. Military organizational support and the rich experiences of peers and mentors facilitate early career development of MNS. The purpose of this article is to present a conceptual framework for research career development of the novice MNS. Using an exemplar POR in military women's health, the concepts are operationalized to illustrate how the military environment enhances the development of a successful POR. Copyright © 2017 Elsevier Inc. All rights reserved.

Association between arsenic exposure from drinking water and proteinuria: results from the Health Effects of Arsenic Longitudinal Study

PubMed Central

Chen, Yu; Parvez, Faruque; Liu, Mengling; Pesola, Gene R; Gamble, Mary V; Slavkovich, Vesna; Islam, Tariqul; Ahmed, Alauddin; Hasan, Rabiul; Graziano, Joseph H; Ahsan, Habibul

2011-01-01

Background Proteinuria has been recognized as a marker for an increased risk of chronic renal disease. It is unclear whether arsenic (As) exposure from drinking water is associated with proteinuria. Methods We evaluated the association between As exposure from drinking water and proteinuria in 11 122 participants in the Health Effects of Arsenic Longitudinal Study (HEALS). Proteinuria was detected by urinary dipstick tests at baseline and at 2-year intervals. As exposure variables included baseline well As and changes in urinary As during follow-up modelled as time-dependent variables in the analyses. Results At baseline, well As was positively related to prevalence of proteinuria; prevalence odds ratios (PORs) for proteinuria in increasing quintiles of well As (≤7, 8–39, 40–91, 92–179 and 180–864 µg/l) were 1.00 (ref), POR 0.99 [95% confidence interval (CI) 0.77–1.27], POR 1.23 (95% CI 0.97–1.57), POR 1.50 (95% CI 1.18–1.89) and POR 1.59 (95% CI 1.26–2.00) (P for trend <0.01). Hazard ratios for incidence of proteinuria were POR 0.83 (95% CI 0.67–1.03) and POR 0.91 (95% CI 0.74–1.12) for participants with a decreasing level of >70 and 17–70 µg/l in urinary As over time, respectively, and were POR 1.17 (95% CI 0.97–1.42) and POR 1.42 (95% CI 1.16–1.73) for participants with an increasing level of 16–68 and >68 µg/l in urinary As over time, respectively, compared with the group with relatively little changes in urinary As as the reference group (urinary As −16 to 15 µg/l). Conclusion The findings suggest that there are adverse effects of As exposure on the risk of proteinuria and the effects are modifiable by recent changes in As exposure. PMID:21343184

Recombinant Salivary Proteins of Phlebotomus orientalis are Suitable Antigens to Measure Exposure of Domestic Animals to Sand Fly Bites

PubMed Central

Sima, Michal; Ferencova, Blanka; Warburg, Alon; Rohousova, Iva; Volf, Petr

2016-01-01

Background Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs) using salivary gland homogenates (SGHs) as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replacement of SGH with recombinant salivary proteins. In East Africa, Phlebotomus orientalis is the main vector of Leishmania donovani, a trypanosomatid parasite causing visceral leishmaniasis. We tested recombinant salivary proteins derived from Ph. orientalis saliva to study exposure of domestic animals to this sand fly species. Methodology/Principal Findings Antigenic salivary proteins from Ph. orientalis were identified by immunoblot and mass spectrometry. Recombinant apyrase rPorSP15, yellow-related protein rPorSP24, ParSP25-like protein rPorSP65, D7-related protein rPorSP67, and antigen 5-related protein rPorSP76 were tested using ELISA with sera of domestic animals from L. donovani foci in Ethiopia where Ph. orientalis is present. Our results highlighted recombinant yellow-related protein rPorSP24 as the most promising antigen, displaying a high positive correlation coefficient as well as good sensitivity and specificity when compared to SGH. This recombinant protein was the most suitable one for testing sera of dogs, sheep, and goats. In addition, a different antigen, rPorSP65 was found efficacious for testing canine sera. Conclusions/Significance Recombinant salivary proteins of Ph. orientalis, specifically rPorSP24, were shown to successfully substitute SGH in serological experiments to measure exposure of domestic animals to Ph. orientalis, the vector of L. donovani. The results suggest that rPorSP24 might be a suitable antigen for detecting anti-Ph. orientalis antibody

Recombinant Salivary Proteins of Phlebotomus orientalis are Suitable Antigens to Measure Exposure of Domestic Animals to Sand Fly Bites.

PubMed

Sima, Michal; Ferencova, Blanka; Warburg, Alon; Rohousova, Iva; Volf, Petr

2016-03-01

Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs) using salivary gland homogenates (SGHs) as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replacement of SGH with recombinant salivary proteins. In East Africa, Phlebotomus orientalis is the main vector of Leishmania donovani, a trypanosomatid parasite causing visceral leishmaniasis. We tested recombinant salivary proteins derived from Ph. orientalis saliva to study exposure of domestic animals to this sand fly species. Antigenic salivary proteins from Ph. orientalis were identified by immunoblot and mass spectrometry. Recombinant apyrase rPorSP15, yellow-related protein rPorSP24, ParSP25-like protein rPorSP65, D7-related protein rPorSP67, and antigen 5-related protein rPorSP76 were tested using ELISA with sera of domestic animals from L. donovani foci in Ethiopia where Ph. orientalis is present. Our results highlighted recombinant yellow-related protein rPorSP24 as the most promising antigen, displaying a high positive correlation coefficient as well as good sensitivity and specificity when compared to SGH. This recombinant protein was the most suitable one for testing sera of dogs, sheep, and goats. In addition, a different antigen, rPorSP65 was found efficacious for testing canine sera. Recombinant salivary proteins of Ph. orientalis, specifically rPorSP24, were shown to successfully substitute SGH in serological experiments to measure exposure of domestic animals to Ph. orientalis, the vector of L. donovani. The results suggest that rPorSP24 might be a suitable antigen for detecting anti-Ph. orientalis antibody-mediated reactions also in other host species.

A Comparison Between PSRK and GERG-2004 Equation of State for Simulation of Non-Isothermal Compressible Natural Gases Mixed with Hydrogen in Pipelines / Porównanie równań stanu opracowanych według metody PSRK oraz GERG-2004 wykorzystanych do symulacji zachowania ściśliwych mieszanin gazu ziemnego i wodoru w rurociągach, w warunkach przepływów nie-izotermicznych

NASA Astrophysics Data System (ADS)

Uilhoorn, Frits E.

2013-06-01

In this work, the GERG-2004 equation of state based on a multi-fluid approximation explicit in the reduced Helmholtz energy is compared with the predictive Soave-Redlich-Kwong group contribution method. In the analysis, both equations of state are compared by simulating a non-isothermal transient flow of natural gas and mixed hydrogen-natural gas in pipelines. Besides the flow conditions also linepack-energy and energy consumption of the compressor station are computed. The gas flow is described by a set of partial differential equations resulting from the conservation of mass, momentum and energy. A pipeline section of the Yamal-Europe gas pipeline on Polish territory has been selected for the case study. W artykule dokonano porównania wyników uzyskanych przy wykorzystaniu równania stanu GERG- 2004 opartego na jawnym przybliżeniu wyników dla wielu cieczy w oparciu o zredukowaną energię Helmhotza oraz wyników uzyskanych w oparciu o metodę Soave-Redlich Kwonga. Obydwa równania stanu porównano poprzez przeprowadzenie symulacji stanów przejściowych przepływów gazu ziemnego oraz mieszanin gazu ziemnego i wodoru w rurociągach w warunkach przepływów nie-izotermicznych. Oprócz warunków przepływu, określono energię w napełnionym układzie oraz zużycie energii przez stację kompresora. Przepływ gazu opisano zbiorem równań różniczkowych cząstkowych, wyprowadzonych w oparciu o prawa zachowania masy, pędu i energii. Jako studium przypadku wybrano fragment rurociągu jamalskiego (Yamal- Europa) przebiegającego przez terytorium Polski.

Weathering resistance of thin plasma polymer films on pre-coated steel =

NASA Astrophysics Data System (ADS)

Serra, Ricardo Gil Henriques

O trabalho apresentado teve origem no projecto de investigacao “Tailored Thin Plasma Polymers Films for Surface Engineering of Coil Coated Steel”, financiado pelo Programa Europeu ECSC Steel Research. Sistemas de aco galvanizado pre-pintado em banda a base de poliester e poliuretano foram submetidos a um processo de polimerizacao por plasma onde um filme fino foi depositado de modo a modificar as propriedades de superficie. Foram usados reactores de catodo oco, microondas e radio frequencia para a deposicao do polimero fino. Os sistemas preparados foram analisados de modo a verificar a influencia do processo de polimerizacao por plasma na alteracao das propriedades barreira dos sistemas pre-pintados em banda. Foi estudado o efeito dos diferentes passos do processo de polimerizacao por plasma, bem como o efeito de diferentes variaveis operatorias. A mistura precursora foi variada de modo a modificar as propriedades da superficie de modo a poder vir a obter maior hidrofobicidade, maior resistencia a marcas digitais, bem como maior facilidade de limpeza. Os testes foram conduzidos em solucao de NaCl 0,5 M. Para o trabalho foram usadas tecnicas de analise da morfologia da superficie como Microscopia de Forca Atomica e Microscopia Electronica de Varrimento. As propriedades electroquimicas dos sistemas foram estudadas por Espectroscopia de Impedancia Electroquimica. A estrutura dos filmes gerados no processo de polimerizacao por plasma foi caracterizada por Microscopia de Transmissao Electronica. A modificacao das propriedades opticas devido ao processo de polimerizacao por plasma foi tambem obtida.

Prognosis and cost-effectiveness of IVF in poor responders according to the Bologna Criteria.

PubMed

Busnelli, Andrea; Somigliana, Edgardo

2018-02-01

Poor ovarian response (POR) to controlled ovarian hyperstimulation for in vitro fertilization (IVF) is one of the most challenging issue in the field of reproductive medicine. However, even if improving IVF outcome in poor responders (PORs) represents a main priority, the lack of a unique definition of POR has hampered research in this area. In order to overcome this impediment, an ESHRE Campus Workshop was organized in Bologna in 2010 and reached a consensus on the criteria for the diagnosis of POR ("Bologna Criteria"). In this review we aimed to estimate the prognostic potential of the ESHRE definition, to elucidate its possible weaknesses and to analyze the economic aspects of IVF in a population of poor responders (PORs). Available evidence confirmed that the Bologna criteria are able to select a population with a poor IVF prognosis thus supporting their validity. Nonetheless, different aspects of the definition have been criticized. The main points of debate concern the homogeneity of the population identified, the cut-off values chosen for the ovarian reserve tests and the risks factors other than age associated with POR. Data concerning the economic profile of IVF in PORs are scanty. The only published study on the argument showed that IVF in these cases is not cost-effective. However, considering the potential substantial impact of cost-effectiveness analyses on public health policies, there is the need for further and independent validations.

Estimación de pequeñas perturbaciones en satélites geocéntricos como un problema inverso

NASA Astrophysics Data System (ADS)

Zadunaisky, P. E.

El movimiento geocéntrico de un satélite artificial es simulado automáticamente por un sistema de ecuaciones diferenciales de segundo orden que incluyen dos funciones perturbadoras. La primera representa el segundo término del potencial gravitatorio de la Tierra y la segunda corresponde al frenado atmosférico. Asumiendo como conocidas, por hipótesis o por mediciones, la posición y velocidad del satélite en instantes sucesivos se estiman las perturbaciones a intervalos sucesivos por un método determinístico. Para ilustrar el método y comprobar la precisión de nuestros resultados hemos simulado dos ejemplos incluyendo valores conocidos de las perturbaciones que luego comparamos con los resultados de nuestro método. El método puede aplicarse por ejemplo para el intervalo de una revolución satelital lo cual permitiría el diseño inmediato de una maniobra correctiva de la órbita satelital.

El Estado de los Bosques de Puerto Rico, 2003

Treesearch

Thomas J. Brandeis; Eileen H. Helmer; Sonja N. Oswalt

2003-01-01

La cobertura forestal de Puerto Rico sigue aumentando y ahora asciende a un 57 por ciento en la isla de Puerto Rico, 85 por ciento en Vieques y 88 por ciento en Culebra. Los bosques subtropicales secos ocupan 50 346 ha, 6832 ha, 2591 ha y 6217 ha en las islas de Puerto Rico, Vieques, Culebra y Mona, respectivamente. El bosque subtropical húmedo, la zona de vida...

"Power-on resets" in cardiac implantable electronic devices during magnetic resonance imaging.

PubMed

Higgins, John V; Sheldon, Seth H; Watson, Robert E; Dalzell, Connie; Acker, Nancy; Cha, Yong-Mei; Asirvatham, Samuel J; Kapa, Suraj; Felmlee, Joel P; Friedman, Paul A

2015-03-01

Magnetic resonance imaging (MRI) has been safely performed in some patients with cardiac implantable electronic devices (CIEDs) under careful monitoring and prespecified conditions. Pacemaker-dependent patients are often excluded, partly because of the potential for "power-on reset" (PoR), which can lead to a change from asynchronous to inhibited pacing with consequent inhibition of pacing due to electromagnetic interference during MRI. The purpose of this study was to review risk factors for PoR during MRI. A prospective study was performed between January 2008 and May 2013 in patients with CIEDs undergoing clinically indicated MRI. Eligible patients were not pacemaker dependent. Devices were interrogated before and after MRI, programmed to an asynchronous mode or an inhibition mode with tachyarrhythmia therapies turned off, and reprogrammed to their original settings after MRI. MRI scans (n = 256) were performed in 198 patients with non-MRI-conditional CIEDs between 2008 and 2013 (median age 66 years; interquartile range 57-77 years; 59% men). PoR occurred during 9 MRI scans (3.5%) in 8 patients. PoR was more frequent with Medtronic devices than with other generator brands (n = 9/139 vs 0/117 [6% vs 0%]; P = .005). Devices with PoR were all released before 2002 and were implanted from 1999 to 2004. Effects of PoR included a decrease in heart rate during MRI (n = 4) and transient anomalous battery life indication (n = 1). All devices functioned normally after MRI. PoR occurs infrequently but can cause deleterious changes in pacing mode and heart rate. MRI should not be performed in pacemaker-dependent patients with older at-risk generators. Continuous monitoring during MRI is essential because unrecognized PoR may inhibit pacing or accelerate battery depletion due to high pacing output. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Hospitalization costs of severe bacterial pneumonia in children: comparative analysis considering different costing methods.

PubMed

Nunes, Sheila Elke Araujo; Minamisava, Ruth; Vieira, Maria Aparecida da Silva; Itria, Alexander; Pessoa, Vicente Porfirio; Andrade, Ana Lúcia Sampaio Sgambatti de; Toscano, Cristiana Maria

2017-01-01

To determine and compare hospitalization costs of bacterial community-acquired pneumonia cases via different costing methods under the Brazilian Public Unified Health System perspective. Cost-of-illness study based on primary data collected from a sample of 59 children aged between 28 days and 35 months and hospitalized due to bacterial pneumonia. Direct medical and non-medical costs were considered and three costing methods employed: micro-costing based on medical record review, micro-costing based on therapeutic guidelines and gross-costing based on the Brazilian Public Unified Health System reimbursement rates. Costs estimates obtained via different methods were compared using the Friedman test. Cost estimates of inpatient cases of severe pneumonia amounted to R$ 780,70/$Int. 858.7 (medical record review), R$ 641,90/$Int. 706.90 (therapeutic guidelines) and R$ 594,80/$Int. 654.28 (Brazilian Public Unified Health System reimbursement rates). Costs estimated via micro-costing (medical record review or therapeutic guidelines) did not differ significantly (p=0.405), while estimates based on reimbursement rates were significantly lower compared to estimates based on therapeutic guidelines (p<0.001) or record review (p=0.006). Brazilian Public Unified Health System costs estimated via different costing methods differ significantly, with gross-costing yielding lower cost estimates. Given costs estimated by different micro-costing methods are similar and costing methods based on therapeutic guidelines are easier to apply and less expensive, this method may be a valuable alternative for estimation of hospitalization costs of bacterial community-acquired pneumonia in children. Determinar e comparar custos hospitalares no tratamento da pneumonia bacteriana adquirida na comunidade por diferentes metodologias de custeio, na perspectiva do Sistema Único de Saúde. Estudo de custo, com coleta de dados primários de uma amostra de 59 crianças com 28 dias a 35 meses de idade

The role of galectin-1 in in vitro and in vivo photodynamic therapy with a galactodendritic porphyrin.

PubMed

Pereira, Patrícia M R; Silva, Sandrina; Ramalho, José S; Gomes, Célia M; Girão, Henrique; Cavaleiro, José A S; Ribeiro, Carlos A F; Tomé, João P C; Fernandes, Rosa

2016-11-01

Conventional photodynamic agents used in clinic are porphyrin-based photosensitizers. However, they have low tumour selectivity, which may induce unwanted side-effects and damage to healthy tissues. In this study, we used a porphyrin with dendritic units of galactose (PorGal 8 ) developed by us, which can target the galactose-binding protein, galectin-1, known to be overexpressed in many tumour tissues. In vitro and in vivo studies had been conducted for the validation of PorGal 8 effectiveness. We showed a specific uptake of PorGal 8 and induction of apoptotic cell death by generating oxidative stress and alterations in the cytoskeleton of bladder cancer cells overexpressing galectin-1. We further validated the photodynamic efficiency of PorGal 8 in athymic nude mice (Balb/c nu/nu) bearing subcutaneously implanted luciferase-positive bladder cancer xenografts, overexpressing galectin-1 protein. PorGal 8 (5 μmol/kg, intraperitoneal), injected 24 h before light delivery (50.4 J/cm 2 ), inhibited tumour growth. We conclude that the use of PorGal 8 enables selective target and cytotoxicity by photodynamic therapy in cancer cells overexpressing galectin-1, preventing undesired phototoxicity in the surrounding healthy tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

Empirical Analysis of Using Erasure Coding in Outsourcing Data Storage With Provable Security

DTIC Science & Technology

2016-06-01

the fastest encoding performance among the four tested schemes. We expected to observe that Cauchy Reed-Solomonwould be faster than Reed- Solomon for all...providing recoverability for POR. We survey MDS codes and select Reed- Solomon and Cauchy Reed- Solomon MDS codes to be implemented into a prototype POR...tools providing recoverability for POR. We survey MDS codes and select Reed- Solomon and Cauchy Reed- Solomon MDS codes to be implemented into a

Co-infection of classic swine H1N1 influenza virus in pigs persistently infected with porcine rubulavirus.

PubMed

Rivera-Benitez, José Francisco; De la Luz-Armendáriz, Jazmín; Saavedra-Montañez, Manuel; Jasso-Escutia, Miguel Ángel; Sánchez-Betancourt, Ivan; Pérez-Torres, Armando; Reyes-Leyva, Julio; Hernández, Jesús; Martínez-Lara, Atalo; Ramírez-Mendoza, Humberto

2016-02-29

Porcine rubulavirus (PorPV) and swine influenza virus infection causes respiratory disease in pigs. PorPV persistent infection could facilitate the establishment of secondary infections. The aim of this study was to analyse the pathogenicity of classic swine H1N1 influenza virus (swH1N1) in growing pigs persistently infected with porcine rubulavirus. Conventional six-week-old pigs were intranasally inoculated with PorPV, swH1N1, or PorPV/swH1N1. A mock-infected group was included. The co-infection with swH1N1 was at 44 days post-infection (DPI), right after clinical signs of PorPV infection had stopped. The pigs of the co-infection group presented an increase of clinical signs compared to the simple infection groups. In all infected groups, the most recurrent lung lesion was hyperplasia of the bronchiolar-associated lymphoid tissue and interstitial pneumonia. By means of immunohistochemical evaluation it was possible to demonstrate the presence of the two viral agents infecting simultaneously the bronchiolar epithelium. Viral excretion of PorPV in nasal and oral fluid was recorded at 28 and 52 DPI, respectively. PorPV persisted in several samples from respiratory tissues (RT), secondary lymphoid organs (SLO), and bronchoalveolar lavage fluid (BALF). For swH1N1, the viral excretion in nasal fluids was significantly higher in single-infected swH1N1 pigs than in the co-infected group. However, the co-infection group exhibited an increase in the presence of swH1N1 in RT, SLO, and BALF at two days after co-infection. In conclusion, the results obtained confirm an increase in the clinical signs of infection, and PorPV was observed to impact the spread of swH1N1 in analysed tissues in the early stage of co-infection, although viral shedding was not enhanced. In the present study, the interaction of swH1N1 infection is demonstrated in pigs persistently infected with PorPV. Copyright © 2016 Elsevier B.V. All rights reserved.

Monóxido de carbono

EPA Pesticide Factsheets

La mayoria de los accidentes causados por envenenamiento por monoxido de carbono (CO) se producen en los hogares y estan relacionados a nuestras actividades diarias como cocinar y usar la calefaccion.

Genetic variations in NADPH-CYP450 oxidoreductase in a Czech Slavic cohort

PubMed Central

Tomková, Mária; Panda, Satya Prakash; Šeda, Ondřej; Baxová, Alice; Hůlková, Martina; Masters, Bettie Sue Siler; Martásek, Pavel

2015-01-01

Background Gene polymorphisms encoding the enzyme NADPH–cytochrome P450 oxidoreductase (POR) contribute to inter-individual differences in drug response. Aim To estimate polymorphic allele frequencies of the POR gene in a Czech Slavic population. Materials & Methods The gene POR was analyzed in 322 Czech Slavic individuals from a control cohort by sequencing and HRM analysis. Results Twenty-five SNP genetic variations were identified. Of these variants, 7 were new, unreported SNPs, including two SNPs in the 5´flanking region (g.4965 C>T and g.4994 G>T), one intronic variant (c.1899 −20C>T), one synonymous SNP (p.20Ala=) and three nonsynonymous SNPs (p.Thr29Ser, p.Pro384Leu and p.Thr529Met). The p.Pro384Leu variant exhibited reduced enzymatic activities compared to wild type. Conclusion New POR variant identification indicates that the number of uncommon variants might be specific for each subpopulation being investigated, particularly germane to the singular role that POR plays in providing reducing equivalents to all CYPs in the endoplasmic reticulum. PMID:25712184

Completing the surrogate motherhood process: parental order reporters' attitudes towards surrogacy arrangements, role ambiguity and role conflict.

PubMed

Purewal, Satvinder; Crawshaw, Marilyn; van den Akker, Olga

2012-06-01

This study investigated the attitudes of parental order reporters (PORs) towards their work with surrogacy arrangements and their experiences of role conflict and role ambiguity. A questionnaire was used to assess PORs' perceptions of their role in parental order [PO] applications, attitudes towards surrogacy arrangements and the legal process and the influence of role ambiguity or conflict. Questionnaires were distributed to all PORs employed by the Children and Family Court Advisory and Support Service in England. Thirty-three PORs participated (response rate 46%) who, on average, had each completed five PO applications (range 1-40). Positive attitudes towards surrogacy and the child's needs for openness about origins were found. Concerns about the inadequacy of preparation and assessment arrangements, overseas arrangements and non-regulation of surrogacy agencies were evident. PORs with high-role ambiguity were more likely to report less positive attitudes towards the emotional consequence of surrogacy on offspring. High scores on role ambiguity and role conflict were reflected in less positive attitudes towards the parties' preparation towards parenthood. These results have implications for training, policy and practice in this area.

Neuraminidase activity of blue eye disease porcine rubulavirus: Specificity, affinity and inhibition studies.

PubMed

Santos-López, Gerardo; Borraz-Argüello, María T; Márquez-Domínguez, Luis; Flores-Alonso, Juan Carlos; Ramírez-Mendoza, Humberto; Priem, Bernard; Fort, Sébastien; Vallejo-Ruiz, Verónica; Reyes-Leyva, Julio; Herrera-Camacho, Irma

2017-10-01

Porcine rubulavirus (PorPV), also known as La Piedad Michoacan Virus (LPMV) causes encephalitis and reproductive failure in newborn and adult pigs, respectively. The hemagglutinin-neuraminidase (HN) glycoprotein is the most exposed and antigenic of the virus proteins. HN plays central roles in PorPV infection; i.e., it recognizes sialic acid-containing cell receptors that mediate virus attachment and penetration; in addition, its neuraminidase (sialic acid releasing) activity has been proposed as a virulence factor. This work describes the purification and characterization of PorPV HN protein (isolate PAC1). The specificity of neuraminidase is restricted to sialyl(α2,3)lactose (3SL). HN showed typical Michaelis-Menten kinetics with fetuin as substrate (km=0.029μM, Vmax=522.8nmolmin -1 mg -1 ). When 3SL was used as substrate, typical cooperative kinetics were found (S 50 =0.15μM, Vmax=154.3nmolmin -1 mg -1 ). The influenza inhibitor zanamivir inhibited the PorPV neuraminidase with IC 50 of 0.24μM. PorPV neuraminidase was activated by Ca 2+ and inhibited by nucleoside triphosphates with the level of inhibition depending on phosphorylation level. The present results open possibilities to study the role of neuraminidase in the pathogenicity of PorPV infection and its potential inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prevalence of asthma and chronic obstructive pulmonary disease in Aboriginal and non-Aboriginal populations: A systematic review and meta-analysis of epidemiological studies

PubMed Central

Ospina, Maria B; Voaklander, Donald C; Stickland, Michael K; King, Malcolm; Senthilselvan, Ambikaipakan; Rowe, Brian H

2012-01-01

BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) have considerable potential for inequities in diagnosis and treatment, thereby affecting vulnerable groups. OBJECTIVE: To evaluate differences in asthma and COPD prevalence between adult Aboriginal and non-Aboriginal populations. METHODS: MEDLINE, EMBASE, specialized databases and the grey literature up to October 2011 were searched to identify epidemiological studies comparing asthma and COPD prevalence between Aboriginal and non-Aboriginal adult populations. Prevalence ORs (PORs) and 95% CIs were calculated in a random-effects meta-analysis. RESULTS: Of 132 studies, eight contained relevant data. Aboriginal populations included Native Americans, Canadian Aboriginals, Australian Aboriginals and New Zealand Maori. Overall, Aboriginals were more likely to report having asthma than non-Aboriginals (POR 1.41 [95% CI 1.23 to 1.60]), particularly among Canadian Aboriginals (POR 1.80 [95% CI 1.68 to 1.93]), Native Americans (POR 1.41 [95% CI 1.13 to 1.76]) and Maori (POR 1.64 [95% CI 1.40 to 1.91]). Australian Aboriginals were less likely to report asthma (POR 0.49 [95% CI 0.28 to 0.86]). Sex differences in asthma prevalence between Aboriginals and their non-Aboriginal counterparts were not identified. One study compared COPD prevalence between Native and non-Native Americans, with similar rates in both groups (POR 1.08 [95% CI 0.81 to 1.44]). CONCLUSIONS: Differences in asthma prevalence between Aboriginal and non-Aboriginal populations exist in a variety of countries. Studies comparing COPD prevalence between Aboriginal and non-Aboriginal populations are scarce. Further investigation is needed to identify and account for factors associated with respiratory health inequalities among Aboriginal peoples. PMID:23248798

Disconnection of the Perirhinal and Postrhinal Cortices Impairs Recognition of Objects in Context But Not Contextual Fear Conditioning

PubMed Central

2017-01-01

The perirhinal cortex (PER) is known to process object information, whereas the rodent postrhinal cortex (POR), homolog to the parahippocampal cortex in primates, is thought to process spatial information. A number of studies, however, provide evidence that both areas are involved in processing contextual information. In this study, we tested the hypothesis that the rat POR relies on object information received from the PER to form complex representations of context. Using three fear-conditioning (FC) paradigms (signaled, unsignaled, and renewal) and two context-guided object recognition tasks (with 3D and 2D objects), we examined the effects of crossed excitotoxic lesions to the POR and the contralateral PER. Performance of rats with crossed lesions was compared with that of rats with ipsilateral POR plus PER lesions and sham-operated rats. We found that rats with contralateral PER–POR lesions were impaired in object–context recognition but not in contextual FC. Therefore, interaction between the POR and PER is necessary for context-guided exploratory behavior but not for associating fear with context. Our results provide evidence for the hypothesis that the POR relies on object and pattern information from the PER to encode representations of context. The association of fear with a context, however, may be supported by alternate cortical and/or subcortical pathways when PER–POR interaction is not available. Our results suggest that contextual FC may represent a special case of context-guided behavior. SIGNIFICANCE STATEMENT Representations of context are important for perception, memory, decision making, and other cognitive processes. Moreover, there is extensive evidence that the use of contextual representations to guide appropriate behavior is disrupted in neuropsychiatric and neurological disorders including developmental disorders, schizophrenia, affective disorders, and Alzheimer's disease. Many of these disorders are accompanied by changes in

Paleoenvironmental implications of taxonomic variation among δ 15 N values of chloropigments

NASA Astrophysics Data System (ADS)

Higgins, Meytal B.; Wolfe-Simon, Felisa; Robinson, Rebecca S.; Qin, Yelun; Saito, Mak A.; Pearson, Ann

2011-11-01

Natural variations in the ratios of nitrogen isotopes in biomass reflect variations in nutrient sources utilized for growth. In order to use δ 15N values of chloropigments of photosynthetic organisms to determine the corresponding δ 15N values of biomass - and by extension, surface waters - the isotopic offset between chlorophyll and biomass must be constrained. Here we examine this offset in various geologically-relevant taxa, grown using nutrient sources that may approximate ocean conditions at different times in Earth's history. Phytoplankton in this study include cyanobacteria (diazotrophic and non-diazotrophic), eukaryotic algae (red and green), and anoxygenic photosynthetic bacteria (Proteobacteria), as well as environmental samples from sulfidic lake water. Cultures were grown using N 2, NO 3-, and NH 4+ as nitrogen sources, and were examined under different light regimes and growth conditions. We find surprisingly high variability in the isotopic difference (δ 15N biomass - δ 15N chloropigment) for prokaryotes, with average values for species ranging from -12.2‰ to +11.7‰. We define this difference as ɛpor, a term that encompasses diagenetic porphyrins and chlorins, as well as chlorophyll. Negative values of ɛpor reflect chloropigments that are 15N-enriched relative to biomass. Notably, this enrichment appears to occur only in cyanobacteria. The average value of ɛpor for freshwater cyanobacterial species is -9.8 ± 1.8‰, while for marine cyanobacteria it is -0.9 ± 1.3‰. These isotopic effects group environmentally but not phylogenetically, e.g., ɛpor values for freshwater Chroococcales resemble those of freshwater Nostocales but differ from those of marine Chroococcales. Our measured values of ɛpor for eukaryotic algae (range = 4.7-8.7‰) are similar to previous reports for pure cultures. For all taxa studied, values of ɛpor do not depend on the type of nitrogen substrate used for growth. The observed environmental control of ɛpor

Disconnection of the Perirhinal and Postrhinal Cortices Impairs Recognition of Objects in Context But Not Contextual Fear Conditioning.

PubMed

Heimer-McGinn, Victoria R; Poeta, Devon L; Aghi, Krishan; Udawatta, Methma; Burwell, Rebecca D

2017-05-03

The perirhinal cortex (PER) is known to process object information, whereas the rodent postrhinal cortex (POR), homolog to the parahippocampal cortex in primates, is thought to process spatial information. A number of studies, however, provide evidence that both areas are involved in processing contextual information. In this study, we tested the hypothesis that the rat POR relies on object information received from the PER to form complex representations of context. Using three fear-conditioning (FC) paradigms (signaled, unsignaled, and renewal) and two context-guided object recognition tasks (with 3D and 2D objects), we examined the effects of crossed excitotoxic lesions to the POR and the contralateral PER. Performance of rats with crossed lesions was compared with that of rats with ipsilateral POR plus PER lesions and sham-operated rats. We found that rats with contralateral PER-POR lesions were impaired in object-context recognition but not in contextual FC. Therefore, interaction between the POR and PER is necessary for context-guided exploratory behavior but not for associating fear with context. Our results provide evidence for the hypothesis that the POR relies on object and pattern information from the PER to encode representations of context. The association of fear with a context, however, may be supported by alternate cortical and/or subcortical pathways when PER-POR interaction is not available. Our results suggest that contextual FC may represent a special case of context-guided behavior. SIGNIFICANCE STATEMENT Representations of context are important for perception, memory, decision making, and other cognitive processes. Moreover, there is extensive evidence that the use of contextual representations to guide appropriate behavior is disrupted in neuropsychiatric and neurological disorders including developmental disorders, schizophrenia, affective disorders, and Alzheimer's disease. Many of these disorders are accompanied by changes in

Porous silicon for drug delivery systems

NASA Astrophysics Data System (ADS)

Abramova, E. N.; Khort, A. M.; Yakovenko, A. G.; Kornilova, D. S.; Slipchenko, E. A.; Prokhorov, D. I.; Shvets, V. I.

2018-01-01

The article deals with main principles of the formation of porous silicon (por-Si) to produce containers for drug delivery systems. Most important por-Si characteristics to produce nanocontainers with required parameters are determined.

Moléculas orgánicas obtenidas en simulaciones experimentales del medio interestelar.

NASA Astrophysics Data System (ADS)

Muñoz-Caro, Guillermo Manuel

Las nubes moleculares son regiones de formación de estrellas, con temperaturas cinéticas entre 10-50 K y densidades de 103-106 átomos cm-3. Su materia está formada por gas y polvo interestelar. Estas partículas de polvo están cubiertas por una fina capa de hielo, de unos 0.01 μm, que contiene H2O y a menudo CO, CO2, CH3OH y NH3. El hielo es presumiblemente irradiado por fotones ultravioleta y rayos cósmicos en las zonas poco profundas de las nubes moleculares y las regiones circunestelares. En un sistema de vacío, P ˜ 10-7 mbar, simulamos la deposición de hielo a partir de 10 K y la irradiación ultravioleta por medio de una lámpara de descarga de hidrógeno activada con microondas. La evolución del hielo se observa por medio de un espectrómetro infrarrojo. De este modo es posible determinar la composición del hielo observado en el medio interestelar y predecir la presencia de moléculas aún no detectadas en el espacio, que han sido producto del procesamiento del hielo en nuestros experimentos. También es posible calentar el sistema hasta temperatura ambiente para sublimar el hielo depositado. Cuando el hielo ha sido previamente irradiado, se observa un residuo compuesto por moléculas orgánicas complejas, algunas prebióticas, como varios ácidos carboxílicos, aminas, amidas, ésteres y en menor proporción moléculas heterocíclicas y aminoácidos. Algunas de estas moléculas podrían detectarse en estado gaseoso por medio de observaciones milimétricas y de radio. También podrían estar presentes en el polvo cometario, cuyo análisis químico está planeado por las misiones Stardust y Rosetta. Mientras tanto, nuestro grupo está llevando a cabo el análisis de partículas de polvo interplanetario (IDPs), algunas de las cuales pueden ser de origen cometario. Al igual que ocurre con los productos obtenidos por irradiación del hielo en nuestros experimentos, algunas IDPs son ricas en material orgánico que contiene oxígeno.

PubMed

Scotta, Ana Verónica; Bongiovanni, Guillermina Azucena; Soria, Elio Andrés

2018-03-21

Antecedentes: Clorpirifos es un pesticida altamente tóxico, que puede producir inmunotoxicidad con efectos deletéreos sobre la salud a nivel mundial. Por otro lado, las plantas americanas pueden tener derivados con actividad protectora e inmunoestimulante. Por lo tanto, debe evaluarse el potencial de estas plantas frente a clorpirifos. Objetivo: Identificar extractos acuosos bioactivos de Lantana grisebachii (LG), Aspidosperma quebracho-blanco (AQ), Peumus boldus (PB), e Ilex paraguariensis (IP), contra la toxicidad de clorpirifos sobre esplenocitos de hembras Balb/c. Materiales y Métodos: Esplenocitos fueron tratados in vitro por 72 horas con 0-35 µg/mL de clorpirifos, 0-100 µg/mL de cada extracto (LG, AQ, PB, IP) y 0-5 µg/mL de concanavalina A. Luego, se midió y analizó estadísticamente viabilidad y muerte celular (tinciones de resazurina y yoduro de propidio), hidroperóxidos, lipoperóxidos (ensayos basados en naranja de xilenol), actividad de la ?-glutamiltranspeptidasa (método de Szasz). Resultados: Clorpirifos redujo la viabilidad celular de forma dosis dependiente, lo que fue contrarrestado por AQ e IP, los que fueron menos activos en las células inducibles por concanavalina A (p<0,05). La toxicidad por clorpirifos implicó la inducción de la ?-glutamiltranspeptidasa con la consecuente reducción de los peróxidos, mientras que AQ y principalmente IP antagonizaron dichas respuestas (p<0,05). Conclusiones: Los extractos de Ilex paraguariensis y Aspidosperma quebracho-blanco protegieron in vitro a los esplenocitos frente a clorpirifos. Este efecto dependió del tipo celular, dado que las células inducibles por concanavalina A fueron más susceptibles a este tóxico.

Sistemas de transporte inteligentes en cruces fronterizos internacionales : un estudio abarcador : facilitando el comercio y mejorando la seguridad en el transporte

DOT National Transportation Integrated Search

2001-04-01

El Programa de Permisosen Fronteras Internacionales (IBC por sus siglas en ingls) fue iniciado bajo la previsin del Acta de Eficiencia de Transporte Terrestre Intermodal (ISTEA por sus siglas en ingls) en 1991. El programa fue concebido origina...

Evaluation of a 3year intervention to increase adoption of safer nursery crop production practices.

PubMed

Chapman, Larry J; Newenhouse, Astrid C; Karsh, Ben-Tzion

2010-01-01

We conducted a 3year intervention to increase awareness and adoption of eight more profitable nursery crop production practices that reduced certain traumatic and musculoskeletal injury hazards. We disseminated information to nursery managers across seven states using information channels they were known to rely on (e.g. trade publications, public events, university Extension, other managers). We evaluated rolling, independent, probability samples (n=1200) with mail questionnaires before the intervention and after each of 3 intervention years. We also evaluated samples (n=250) from a comparison group of New Zealand nursery managers. The intervention was associated with increased awareness of four of the eight practices among US managers after year 3 compared to their baseline: zippers (20 vs. 32%, p=0.000), stools (11 vs. 22%, p=0.001), pruners (29 vs. 40%, p=0.014), and tarps (24 vs. 33%, p=0.009). There were no changes in adoption. New Zealand manager awareness was increased for hoes after year 2 compared to their baseline (35 vs. 52%, p=0.010). A modest, regionwide information dissemination intervention was associated with increased awareness, but not adoption.

Nuevos sistemas de frecuencia intermedia para el IAR

NASA Astrophysics Data System (ADS)

Olalde, J. C.; Perilli, D.; Larrarte, J. J.

Se presenta el diagrama en bloques de los nuevos sistemas de Frecuencia Intermedia para los dos radiómetros instalados en el IAR. Entre las características más importantes del sistema podemos mencionar la posibilidad de conectar cualquiera de las dos antenas a los ``backend" disponibles: analizador espectral de alta resolución (META II) de 0,05 Hz, autocorrelador de 1008 canales y contínuo. Se incorporan al sistema nuevos sintetizadores de frecuencia implementados con PLL y la moderna técnica de síntesis digital directa. Por último, el conjunto del sistema es susceptible de ser configurado por las computadoras de adquisición de datos, supervisadas por otra, que entrega el estado de funcionamiento actual y evita la selección de configuraciones incorrectas por parte del usuario.

Novel approach for III-N on Si (111) templates fabrication by low-temperature PA MBE using porous Si layer

NASA Astrophysics Data System (ADS)

Zolotukhin, D.; Seredin, P.; Lenshin, A.; Goloshchapov, D.; Mizerov, A.

2017-11-01

We report on successful growth of GaN nanorods by low-temperature plasma-assisted molecular beam epitaxy on a Si(111) substrate with and without preformed thin porous Si layer (por-Si). The deposited GaN initially forms islands which act as a seed for the wires. Porous structure of the por-Si layer helps to control nucleation islands sizes and achieve homogeneous distribution of the nanorods diameters. In addition 850 nm-thick crack-free GaN layer was formed on Si(111) substrate with preformed por-Si layer.

Microbial diversity and dynamics during the production of May bryndza cheese.

PubMed

Pangallo, Domenico; Saková, Nikoleta; Koreňová, Janka; Puškárová, Andrea; Kraková, Lucia; Valík, Lubomír; Kuchta, Tomáš

2014-01-17

paradoxus. The diversity of yeasts and fungi encompassed Alternaria alternata, "Ascomycete sp.", Aspergillus fumigatus, Beauveria brongniartii, Candida xylopsoci, C. inconspicua, Cladosporium cladosporioides, Debaromyces hansenii, Fomes fomentarius, Galactomyces candidus, Gymnoascus reesii, Chaetomium globosum, Kluyveromyces marxianus, Metarhizium anisopliae, Penicillium aurantiogriseum, P. camemberti, P. freii, P. polonicum, P. viridicatum, Pichia kudriavzevii, Sordaria alcina, Trichosporon lactis and Yarrowia lipolytica. © 2013.

Microbial and chemical transformation studies of the bioactive marine sesquiterpenes (S)-(+)-curcuphenol and -curcudiol isolated from a deep reef collection of the Jamaican sponge Didiscus oxeata.

PubMed

El Sayed, Khalid A; Yousaf, Muhammad; Hamann, Mark T; Avery, Mitchell A; Kelly, Michelle; Wipf, Peter

2002-11-01

Microbial and chemical transformation studies of the marine sesquiterpene phenols (S)-(+)-curcuphenol (1) and (S)-(+)-curcudiol (2), isolated from the Jamaican sponge Didiscus oxeata, were accomplished. Preparative-scale fermentation of 1 with Kluyveromyces marxianus var. lactis (ATCC 2628) has resulted in the isolation of six new metabolites: (S)-(+)-15-hydroxycurcuphenol (3), (S)-(+)-12-hydroxycurcuphenol (4), (S)-(+)-12,15-dihydroxycurcuphenol (5), (S)-(+)-15-hydroxycurcuphenol-12-al (6), (S)-(+)-12-carboxy-10,11-dihydrocurcuphenol (7), and (S)-(+)-12-hydroxy-10,11-dihydrocurcuphenol (8). Fourteen-days incubation of 1 with Aspergillus alliaceus (NRRL 315) afforded the new compounds (S)-(+)-10beta-hydroxycurcudiol (9), (S)-(+)-curcudiol-10-one (10), and (S)-(+)-4-[1-(2-hydroxy-4-methyl)phenyl)]pentanoic acid (11). Rhizopus arrhizus (ATCC 11145) and Rhodotorula glutinus (ATCC 15125) afforded (S)-curcuphenol-1alpha-D-glucopyranoside (12) and (S)-curcudiol-1alpha-D-glucopyranoside (13) when incubated for 6 and 8 days with 1 and 2, respectively. The absolute configuration of C(10) and C(11) of metabolites 7-9 was established by optical rotation computations. Reaction of 1 with NaNO(2) and HCl afforded (S)-(+)-4-nitrocurcuphenol (14) and (S)-(+)-2-nitrocurcuphenol (15) in a 2:1 ratio. Acylation of 1 and 2 with isonicotinoyl chloride afforded the expected esters (S)-(+)-curcuphenol-1-O-isonicotinate (16) and (S)-(+)-curcudiol-1-O-isonicotinate (17), respectively. Curcuphenol (1) shows potent antimicrobial activity against Candida albicans, Cryptococcus neoformans, methicillin-resistant Staphylococcus aureus, and S. aureus with MIC and MFC/MBC ranges of 7.5-25 and 12.5-50 microg/mL, respectively. Compounds 1 and 3 also display in vitro antimalarial activity against Palsmodium falciparium (D6 clone) with MIC values of 3600 and 3800 ng/mL, respectively (selectivity index >1.3). Both compounds were also active against P. falciparium (W2 clone) with MIC values of 1800 (S

Construction of lactose-consuming Saccharomyces cerevisiae for lactose fermentation into ethanol fuel.

PubMed

Zou, Jing; Guo, Xuewu; Shen, Tong; Dong, Jian; Zhang, Cuiying; Xiao, Dongguang

2013-04-01

Two lactose-consuming diploid Saccharomyces cerevisiae strains, AY-51024A and AY-51024M, were constructed by expressing the LAC4 and LAC12 genes of Kluyveromyces marxianus in the host strain AY-5. In AY-51024A, both genes were targeted to the ATH1 and NTH1 gene-encoding regions to abolish the activity of acid/neutral trehalase. In AY-51024M, both genes were respectively integrated into the MIG1 and NTH1 gene-encoding regions to relieve glucose repression. Physiologic studies of the two transformants under anaerobic cultivations in glucose and galactose media indicated that the expression of both LAC genes did not physiologically burden the cells, except for AY-51024A in glucose medium. Galactose consumption was initiated at higher glucose concentrations in the MIG1 deletion strain AY-51024M than in the corresponding wild-type strain and AY-51024A, wherein galactose was consumed until glucose was completely depleted in the mixture. In lactose medium, the Sp. growth rates of AY-51024A and AY-51024M under anaerobic shake-flasks were 0.025 and 0.067 h(-1), respectively. The specific lactose uptake rate and ethanol production of AY-51024M were 2.50 g lactose g CDW(-1) h(-1) and 23.4 g l(-1), respectively, whereas those of AY-51024A were 0.98 g lactose g CDW(-1) h(-1) and 24.3 g lactose g CDW(-1) h(-1), respectively. In concentrated cheese whey powder solutions, AY-51024M produced 63.3 g l(-1) ethanol from approximately 150 g l(-1) initial lactose in 120 h, conversely, AY-51024A consumed 63.7 % of the initial lactose and produced 35.9 g l(-1) ethanol. Therefore, relieving glucose repression is an effective strategy for constructing lactose-consuming S. cerevisiae.

Yeast Biodiversity from DOQ Priorat Uninoculated Fermentations.

PubMed

Padilla, Beatriz; García-Fernández, David; González, Beatriz; Izidoro, Iara; Esteve-Zarzoso, Braulio; Beltran, Gemma; Mas, Albert

2016-01-01

Climate, soil, and grape varieties are the primary characteristics of terroir and lead to the definition of various appellations of origin. However, the microbiota associated with grapes are also affected by these conditions and can leave a footprint in a wine that will be part of the characteristics of terroir. Thus, a description of the yeast microbiota within a vineyard is of interest not only to provide a better understanding of the winemaking process, but also to understand the source of microorganisms that maintain a microbial footprint in wine from the examined vineyard. In this study, two typical grape varieties, Grenache and Carignan, have been sampled from four different vineyards in the DOQ Priorat winegrowing region. Afterward, eight spontaneous alcoholic fermentations containing only grapes from one sampling point and of one variety were conducted at laboratory scale. The fermentation kinetics and yeast population dynamics within each fermentation experiment were evaluated. Yeast identification was performed by RFLP-PCR of the 5.8S-ITS region and by sequencing D1/D2 of the 26S rRNA gene of the isolates. The fermentation kinetics did not indicate clear differences between the two varieties of grapes or among vineyards. Approximately 1,400 isolates were identified, exhibiting high species richness in some fermentations. Of all the isolates studied, approximately 60% belong to the genus Hanseniaspora, 16% to Saccharomyces, and 11% to Candida. Other minor genera, such as Hansenula, Issatchenkia, Kluyveromyces, Saccharomycodes, and Zygosaccharomyces, were also found. The distribution of the identified yeast throughout the fermentation process was studied, and Saccharomyces cerevisiae was found to be present mainly at the end of the fermentation process, while Aureobasidium pullulans was isolated primarily during the first days of fermentation in three of the eight spontaneous fermentations. This work highlights the complexity and diversity of the vineyard

Yeast Biodiversity from DOQ Priorat Uninoculated Fermentations

PubMed Central

Padilla, Beatriz; García-Fernández, David; González, Beatriz; Izidoro, Iara; Esteve-Zarzoso, Braulio; Beltran, Gemma; Mas, Albert

2016-01-01

Climate, soil, and grape varieties are the primary characteristics of terroir and lead to the definition of various appellations of origin. However, the microbiota associated with grapes are also affected by these conditions and can leave a footprint in a wine that will be part of the characteristics of terroir. Thus, a description of the yeast microbiota within a vineyard is of interest not only to provide a better understanding of the winemaking process, but also to understand the source of microorganisms that maintain a microbial footprint in wine from the examined vineyard. In this study, two typical grape varieties, Grenache and Carignan, have been sampled from four different vineyards in the DOQ Priorat winegrowing region. Afterward, eight spontaneous alcoholic fermentations containing only grapes from one sampling point and of one variety were conducted at laboratory scale. The fermentation kinetics and yeast population dynamics within each fermentation experiment were evaluated. Yeast identification was performed by RFLP-PCR of the 5.8S-ITS region and by sequencing D1/D2 of the 26S rRNA gene of the isolates. The fermentation kinetics did not indicate clear differences between the two varieties of grapes or among vineyards. Approximately 1,400 isolates were identified, exhibiting high species richness in some fermentations. Of all the isolates studied, approximately 60% belong to the genus Hanseniaspora, 16% to Saccharomyces, and 11% to Candida. Other minor genera, such as Hansenula, Issatchenkia, Kluyveromyces, Saccharomycodes, and Zygosaccharomyces, were also found. The distribution of the identified yeast throughout the fermentation process was studied, and Saccharomyces cerevisiae was found to be present mainly at the end of the fermentation process, while Aureobasidium pullulans was isolated primarily during the first days of fermentation in three of the eight spontaneous fermentations. This work highlights the complexity and diversity of the vineyard

Biodiversity and probiotic potential of yeasts isolated from Fura, a West African spontaneously fermented cereal.

PubMed

Pedersen, Line Lindegaard; Owusu-Kwarteng, James; Thorsen, Line; Jespersen, Lene

2012-10-01

Fura is a spontaneously fermented pearl millet product consumed in West Africa. The yeast species involved in the fermentation were identified by pheno- and genotypic methods to be Candida krusei, Kluyveromyces marxianus, Candida tropicalis, Candida rugosa, Candida fabianii, Candida norvegensis and Trichosporon asahii. C. krusei and K. marxianus were found to be the dominant species. Survival in pH 2.5 or in the presence of bile salts (0.3% (w/v) oxgall) and growth at 37°C were independently determined as indicators of the survival potential of the isolates during passage through the human gastrointestinal tract. Selected yeast species isolates were assessed for their probiotic potential. All of the examined yeast isolates survived and grew at human gastrointestinal conditions in pH 2.5, 0.3% (w/v) oxgall at 37°C. The effect on the transepithelial electrical resistance (TEER) across polarized monolayers of intestinal epithelial cells of human (Caco-2) and porcine (IPEC-J2) origin, were determined. The Caco-2 cells and IPEC-J2 cells displayed clearly different relative TEER results. The strains of C. krusei, K. marxianus, C. rugosa and T. asahii were able to increase the relative TEER of Caco-2 monolayers after 48h. In comparison, the relative TEER of IPEC-J2 monolayers decreased when exposed to the same yeasts, even though T. asahii did not differ significantly from Saccharomyces cerevisiae var. boulardii which is used as a human probiotic. C. tropicalis resulted in the largest relative TEER decrease for both the human and the porcine cell model assays. Hyphal growth was observed for C. albicans and C. tropicalis after 48h of incubation with polarized Caco-2 monolayers, whereas this was not the case for the remaining yeast species. In the present study new yeast strains with potential probiotic properties have been isolated to be used potentially as starter cultures for fura production. Copyright © 2012 Elsevier B.V. All rights reserved.

Identification of uncommon oral yeasts from cancer patients by MALDI-TOF mass spectrometry.

PubMed

Aslani, Narges; Janbabaei, Ghasem; Abastabar, Mahdi; Meis, Jacques F; Babaeian, Mahasti; Khodavaisy, Sadegh; Boekhout, Teun; Badali, Hamid

2018-01-08

Opportunistic infections due to Candida species occur frequently in cancer patients because of their inherent immunosuppression. The aim of the present study was to investigate the epidemiology of yeast species from the oral cavity of patients during treatment for oncological and haematological malignancies. MALDI-TOF was performed to identify yeasts isolated from the oral cavity of 350 cancer patients. Moreover, antifungal susceptibility testing was performed in according to CLSI guidelines (M27-A3). Among 162 yeasts and yeast-like fungi isolated from the oral cavity of cancer patients, Candida albicans was the most common species (50.6%), followed by Candida glabrata (24.7%), Pichia kudriavzevii (Candida krusei (9.9%)), Candida tropicalis (4.3%), Candida dubliniensis (3.7%), Kluyveromyces marxianus (Candida kefyr (3.7%)) and Candida parapsilosis (1%). In addition, uncommon yeast species i.e., Saprochaete capitata, Saccharomyces cerevisiae, Clavispora lusitaniae (C. lusitaniae) and Pichia kluyveri (C. eremophila) were recovered from oral lesions. Oral colonization by C. albicans, non-albicans Candida species and uncommon yeasts were as follow; 55%, 44% and 1%, whereas oral infection due to C. albicans was 33.3%, non-albicans Candida species 60.6%, and uncommon yeasts 6.1%. Poor oral hygiene and xerostomia were identified as independent risk factors associated with oral yeast colonization. The overall resistance to fluconazole was 11.7% (19/162). Low MIC values were observed for anidulafungin for all Candida and uncommon yeast species. This current study provides insight into the prevalence and susceptibility profiles of Candida species, including emerging Candida species and uncommon yeasts, isolated from the oral cavity of Iranian cancer patients. The incidence of oral candidiasis was higher amongst patients with hematological malignancies. The majority of oral infections were caused by non-albicans Candida species which were often more resistant to anti

Microbicidas Metodo de Prevencion en VIH/SIDA Controlado por Mujeres

PubMed Central

Ruiz, Cindy; Torres, Viviana; Cianelli, Rosina; Ferrer, Lilian

2016-01-01

HIV/AIDS continues to expand throughout the world, and in recent times has had a severe impact on the number of women living with HIV. Access to methods of prevention for HIV/AIDS around the world is limited and for many women may not be feasible. Examples of such methods are sexual abstinence, which though recognized as an effective method of prevention is difficult for many women to achieve. Mutual fidelity is another option, but many women cannot control the sexual behavior of their partners. Finally, the male condom continues to be an available method of HIV prevention for sexually active people. However, in many places, gender inequality, social norms, and economic disparities severely limit women's capacity to negotiate the use of a condom with their partner. For this reason, an urgent need exists to develop a product for the prevention of HIV/AIDS that can be handled by women. Microbicides, products that can reduce HIV risk when applied intravaginally, hold promise for stopping the advance of HIV/AIDS, especially when considering that women can make their own decisions about whether to use them when other methods of prevention are not available. The objective of the current literature review was to understand the scientific advances related to microbicides in the prevention of HIV/AIDS in women through the analysis of available literature in this area. Interest in this topic emerged from the need to contribute to women's health and HIV/AIDS prevention. To achieve this review's objective, a search was carried out in multiple databases, including OVID, PUBMED, PROQUEST, and CINAHL, as well as published materials from organizations related to this area such as UNAIDS and CONASIDA, and literature available from the Internet. Upon completion of the literature review, it was concluded that microbicides are an effective method for preventing HIV/AIDS for women as well as their partners. Although they have a high level of acceptance among the female population, the majority of microbicides are still in clinical studies, requiring further evaluation for their safe use in humans. There are 3 microbicides in the final phases of clinical studies that will soon be available on the market. One of these was found to be 60% effective in protecting against the transmission of HIV and was used by women in 50% of their sexual activity, which resulted in avoiding approximately 2.5 million new HIV infections in men, women, and children over a 3-year period. PMID:28111528

Microbicidas Metodo de Prevencion en VIH/SIDA Controlado por Mujeres.

PubMed

Ruiz, Cindy; Torres, Viviana; Cianelli, Rosina; Ferrer, Lilian

2009-03-01

HIV/AIDS continues to expand throughout the world, and in recent times has had a severe impact on the number of women living with HIV. Access to methods of prevention for HIV/AIDS around the world is limited and for many women may not be feasible. Examples of such methods are sexual abstinence, which though recognized as an effective method of prevention is difficult for many women to achieve. Mutual fidelity is another option, but many women cannot control the sexual behavior of their partners. Finally, the male condom continues to be an available method of HIV prevention for sexually active people. However, in many places, gender inequality, social norms, and economic disparities severely limit women's capacity to negotiate the use of a condom with their partner. For this reason, an urgent need exists to develop a product for the prevention of HIV/AIDS that can be handled by women. Microbicides, products that can reduce HIV risk when applied intravaginally, hold promise for stopping the advance of HIV/AIDS, especially when considering that women can make their own decisions about whether to use them when other methods of prevention are not available. The objective of the current literature review was to understand the scientific advances related to microbicides in the prevention of HIV/AIDS in women through the analysis of available literature in this area. Interest in this topic emerged from the need to contribute to women's health and HIV/AIDS prevention. To achieve this review's objective, a search was carried out in multiple databases, including OVID, PUBMED, PROQUEST, and CINAHL, as well as published materials from organizations related to this area such as UNAIDS and CONASIDA, and literature available from the Internet. Upon completion of the literature review, it was concluded that microbicides are an effective method for preventing HIV/AIDS for women as well as their partners. Although they have a high level of acceptance among the female population, the majority of microbicides are still in clinical studies, requiring further evaluation for their safe use in humans. There are 3 microbicides in the final phases of clinical studies that will soon be available on the market. One of these was found to be 60% effective in protecting against the transmission of HIV and was used by women in 50% of their sexual activity, which resulted in avoiding approximately 2.5 million new HIV infections in men, women, and children over a 3-year period.

Decade of Venezuela’s President Hugo Chavez, Por Ahora

DTIC Science & Technology

2009-04-01

minor production source of opium and cocoa , Venezuela is important in the transit of narcotics between Columbia and the US. 60 61 Mindful of this, a...took over.91 To highlight the significance of oil to Venezuela , in 2006, oil represented 91% of its exports compared to 80% five years earlier.92...methodology to examine the last ten years of Venezuelas Hugo Chavez presidency and the significant aspects in terms of US security. The paper contents

On the Use of "Por" Plus Agent with "Se" Construction

ERIC Educational Resources Information Center

De Mello, George

1978-01-01

Two explanations for the role of "se" in such constructions as "Se construyen casas" are given by grammarians; one states that it is a passive interpretation ("Houses are built"), the other advocates an impersonal interpretation ("One builds houses"). Different views are presented and analyzed. (Author/NCR)

Time spent traveling in motor vehicles and its association with overweight and abdominal obesity in Colombian adults who do not own a car.

PubMed

Flórez Pregonero, Alberto; Gómez, Luis Fernando; Parra, Diana C; Cohen, Daniel D; Arango Paternina, Carlos Mario; Lobelo, Felipe

2012-06-01

This study examined associations between time spent traveling in motor vehicles per week (TSTMV) and BMI and abdominal obesity (AO) among Colombian adults residing in urban areas who do not own car. Secondary data analysis of the 2005 National Nutrition Survey of Colombia was conducted. TSTMV was assessed using the long International Physical Activity Questionnaire. Body composition was measured in 7900 adults. Polytomous and binary logistic regressions were conducted, stratified by gender and adjusted for confounders, including physical activity (PA). Forty-two percent of participants were either overweight or obese according to their BMI, and 22.4% had AO. Males in the middle (10 to 149 min) and highest (>150 min) TSTMV tertiles were more likely to be overweight (POR=1.58, 95% CI=1.13-2.21 and POR=1.55, 95% CI=1.12-2.15 respectively, p-trend=0.012), obese (POR=2.39, 95% CI=1.43-3.99 and POR=1.93, 95% CI=1.22-3.08 respectively, p trend=0.019) and to have AO (POR=1.81, 95% CI=1.18-2.78 and POR=1.73, 95% CI=1.18-2.54 respectively, p-trend=0.009). Associations were not significant in females. TSTMV was positively associated with overweight and AO in adult Colombian males even after adjusting for PA. These findings highlight the potential deleterious health effects of sedentary behaviors such as prolonged traveling time, independently of having met PA recommendations. Copyright © 2012 Elsevier Inc. All rights reserved.

[Not Available].

PubMed

San Mauro Martin, Ismael; Mendive Dubourdieu, Paula; Paredes Barato, Víctor; Garicano Vilar, Elena

2016-07-19

Introducción: la tradición de la comida picante desempeña un papel muy importante en el gusto por este tipo de comida y su tolerancia. Las preferencias alimentarias muestran influencia genética y ambiental.Objetivos: estudiar la tolerancia y el gusto por el picante de tres poblaciones, y la influencia hereditaria y del ambiente.Métodos:se realizó una encuesta a 522 sujetos, de tres continentes (Asia, Europa y Latinoamérica) en tres idiomas (español, inglés y chino) a través de Internet. Se realizaron preguntas acerca de la tolerancia al picante, el gusto por los alimentos picantes, su uso, la edad de comienzo de consumo, el gusto del padre y de la madre y si ella lo consumía durante el embarazo y/o lactancia.Resultados: existe diferencia entre el gusto por el picante del hijo y el sexo (p < 0,001), la tolerancia (p < 0,001) y, solo en el sexo femenino, el gusto de la madre por el picante (p < 0,001), su consumo durante el embarazo (p < 0,001) y la lactancia (p = 0,005) y el gusto del padre por el picante (p = 0,003). Existe correlación entre el continente de residencia (p = 0,007) y de nacimiento (p = 0,012) y la tolerancia a los alimentos picantes.Conclusión: la influencia de los progenitores, el género y la composición corporal se relacionaron con gustos y tolerancias diferentes.

Sunburn and sun-protective behaviors among adults with and without previous nonmelanoma skin cancer: a population-based study

PubMed Central

Fischer, Alexander H.; Wang, Timothy S.; Yenokyan, Gayane; Kang, Sewon; Chien, Anna L.

2016-01-01

Background Individuals with previous nonmelanoma skin cancer (NMSC) are at increased risk for subsequent skin cancer, and should therefore limit UV exposure. Objective To determine whether individuals with previous NMSC engage in better sun protection than those with no skin cancer history. Methods We pooled self-reported data (2005 and 2010 National Health Interview Surveys) from US non-Hispanic white adults (758 with and 34,161 without previous NMSC). We calculated adjusted prevalence odds ratios (aPOR) and 95% confidence intervals (95% CI), taking into account the complex survey design. Results Individuals with previous NMSC versus no history of NMSC had higher rates of frequent use of shade (44.3% versus 27.0%; aPOR=1.41; 1.16–1.71), long sleeves (20.5% versus 7.7%; aPOR=1.55; 1.21–1.98), a wide-brimmed hat (26.1% versus 10.5%; aPOR=1.52; 1.24–1.87), and sunscreen (53.7% versus 33.1%; aPOR=2.11; 95% CI=1.73–2.59), but did not have significantly lower odds of recent sunburn (29.7% versus 40.7%; aPOR=0.95; 0.77–1.17). Among subjects with previous NMSC, recent sunburn was inversely associated with age, sun avoidance, and shade but not sunscreen. Limitations Self-reported cross-sectional data and unavailable information quantifying regular sun exposure. Conclusion Physicians should emphasize sunburn prevention when counseling patients with previous NMSC, especially younger adults, focusing on shade and sun avoidance over sunscreen. PMID:27198078

Factors associated with anemia in refugee children.

PubMed

Hassan, K; Sullivan, K M; Yip, R; Woodruff, B A

1997-11-01

A nutrition survey was performed in 1990 among children 6 through 35 mo of age living in Palestinian refugee camps in Syria, Jordan, the West Bank, Gaza Strip and Lebanon. Overall, 67% [95% confidence interval (CI): 66, 68] were anemic (hemoglobin <110 g/L), ranging from 54% in the West Bank to 75% in Syria. The following factors were significantly associated with anemia in one or more of three age groups (6-11.9, 12-23.9 and 24-35.9 mo) by logistic regression: living in Syria, Lebanon, or Gaza [with prevalence odds ratios (POR) in the range of 1.4-2.6 depending on the age group and area, relative to children living in Jordan]; never having been breast-fed (POR = 1.7); male sex (POR = 1.2); maternal illiteracy (POR = 1.4 relative to those with >/=6 y of education); having a recent (within 2 wk) or current episode of fever or diarrhea; and stunting. Recent or current illness and stunting interacted in two age groups with the general trend of stunted children with recent or current illness having high POR. Early childhood anemia is associated with factors reflecting poor socioeconomic status and recent diarrheal and febrile illnesses in Palestinian refugee camps.

Risk of specific congenital abnormalities in offspring of women with diabetes.

PubMed

Nielsen, G L; Nørgard, B; Puho, E; Rothman, K J; Sørensen, H T; Czeizel, A E

2005-06-01

To assess the extent to which the increased risk of congenital abnormalities seen in women with pre-gestational insulin-treated diabetes mellitus is unspecific or related to the embryology of specific organs. Cases with congenital abnormalities were identified in the population-based Hungarian Congenital Abnormality Registry from 1980 to 1996 with two newborn children without congenital abnormality selected from the National Birth Registry as controls. We adjusted for parity, maternal age, and use of antipsychotic drugs. Among cases we found 63/22,843 babies with maternal diabetes compared with 50/38,151 in the control group [adjusted prevalence odds ratio (POR) 2.1; 95% CI 1.5-3.1]. The association was strongest for the following congenital abnormalities: renal agenesis (POR: 14.8; 95% CI, 3.5-62.1), obstructive congenital abnormalities of the urinary tract (POR: 4.3; 95% CI, 1.3-13.9), cardiovascular congenital abnormalities (POR: 3.4; 95% CI, 2.0-5.7), and multiple congenital abnormalities (POR: 5.0; 95% CI, 2.4-10.2). These data indicate that pre-gestational maternal diabetes is associated with strong teratogenic effects on the kidney, urinary tract, and heart, and strongly associated with multiple congenital abnormalities. We found no material association between diabetes and spinal congenital abnormalities and limb deficiencies.

Using MOMP typing as an epidemiological tool to investigate outbreaks caused by milkborne Campylobacter jejuni isolates in California

USDA-ARS?s Scientific Manuscript database

We describe using major outer membrane protein (MOMP) typing as a screen to compare the C. jejuni porA gene sequences of clinical outbreak strains from human stool with the porA sequences of dairy farm strains isolated during two milkborne campylobacteriosis outbreak investigations in California. Th...

Unidades generadoras de energía eléctrica para servicios públicos: Revocación del Plan de Energía Limpia: Propuesta

EPA Pesticide Factsheets

La EPA está proponiendo la revocación del Plan de Energía Limpia (CPP, por sus siglas en inglés) – después de completar una revisión minuciosa como fue dictaminada por la Orden Ejecutiva de Independencia Energética.

78 FR 29322 - Silicon Metal From the People's Republic of China: Final Results and Final No Shipments...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-20

... People's Republic of China: Final Results and Final No Shipments Determination of Antidumping Duty... the People's Republic of China (``PRC'').\\1\\ The period of review (``POR'') is June 1, 2011, through... any reviewable transactions during the POR. \\1\\ See Silicon Metal From the People's Republic of China...

77 FR 28570 - Honey From Argentina: Extension of Time Limit for the Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-357-812] Honey From Argentina... administrative review for the 2009-2010 period of review (POR) of honey from Argentina. See Honey From Argentina... producers/exporters of honey from Argentina during the POR.\\1\\ \\1\\ See Preliminary Results for a detailed...

El nuevo panorama de la Dinámica Galáctica

NASA Astrophysics Data System (ADS)

Pivovaroff, Michael James

En general, la tendencia imperante en Dinámica Galáctica ha sido considerar que los movimientos estelares son básicamente regulares y que el caos no tiene mayor relevancia en los sistemas estelares. Sin embargo, en el último lustro se vienen acumulando pruebas de la importancia del movimiento caótico en ciertos sistemas estelares que existen en la naturaleza. Por una parte, sobre todo el grupo de David Merritt, lo ha mostrado en los casos de galaxias elípticas con concentraciones centrales de materia; por otra parte, en nuestro propio grupo, lo hemos mostrado para el caso de los satélites galácticos. Las consecuencias de estos hallazgos son tanto de tipo técnico, por la necesidad de construir modelos que contengan órbitas caóticas, como astrofísico, por los efectos del caos sobre la estacionariedad y evolución de los sistemas estelares en los que se presenta.

Tyrosine oxidation in heme oxygenase: examination of long-range proton-coupled electron transfer.

PubMed

Smirnov, Valeriy V; Roth, Justine P

2014-10-01

Heme oxygenase is responsible for the degradation of a histidine-ligated ferric protoporphyrin IX (Por) to biliverdin, CO, and the free ferrous ion. Described here are studies of tyrosyl radical formation reactions that occur after oxidizing Fe(III)(Por) to Fe(IV)=O(Por(·+)) in human heme oxygenase isoform-1 (hHO-1) and the structurally homologous protein from Corynebacterium diphtheriae (cdHO). Site-directed mutagenesis on hHO-1 probes the reduction of Fe(IV)=O(Por(·+)) by tyrosine residues within 11 Å of the prosthetic group. In hHO-1, Y58· is implicated as the most likely site of oxidation, based on the pH and pD dependent kinetics. The absence of solvent deuterium isotope effects in basic solutions of hHO-1 and cdHO contrasts with the behavior of these proteins in the acidic solution, suggesting that long-range proton-coupled electron transfer predominates over electron transfer.

Genetic variations in NADPH-CYP450 oxidoreductase in a Czech Slavic cohort.

PubMed

Tomková, Mária; Panda, Satya Prakash; Šeda, Ondřej; Baxová, Alice; Hůlková, Martina; Siler Masters, Bettie Sue; Martásek, Pavel

2015-01-01

Estimating polymorphic allele frequencies of the NADPH-CYP450 oxidoreductase (POR) gene in a Czech Slavic population. The POR gene was analyzed in 322 individuals from a control cohort by sequencing and high resolution melting analysis. We identified seven unreported SNP genetic variations, including two SNPs in the 5' flanking region (g.4965C>T and g.4994G>T), one intronic variant (c.1899-20C>T), one synonymous SNP (p.20Ala=) and three nonsynonymous SNPs (p.Thr29Ser, p.Pro384Leu and p.Thr529Met). The p.Pro384Leu variant exhibited reduced enzymatic activities compared with wild-type. New POR variant identification indicates the number of uncommon variants might be specific for each subpopulation being investigated, particularly germane to the singular role that POR plays in providing reducing equivalents to all CYP450s in the endoplasmic reticulum. Original submitted 15 September 2014; Revision submitted 17 November 2014.

Observational study to calculate addictive risk to opioids: a validation study of a predictive algorithm to evaluate opioid use disorder.

PubMed

Brenton, Ashley; Richeimer, Steven; Sharma, Maneesh; Lee, Chee; Kantorovich, Svetlana; Blanchard, John; Meshkin, Brian

2017-01-01

Opioid abuse in chronic pain patients is a major public health issue, with rapidly increasing addiction rates and deaths from unintentional overdose more than quadrupling since 1999. This study seeks to determine the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated single-nucleotide polymorphisms (SNPs). The Proove Opioid Risk (POR) algorithm determines the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated SNPs. In a validation study with 258 subjects with diagnosed opioid use disorder (OUD) and 650 controls who reported using opioids, the POR successfully categorized patients at high and moderate risks of opioid misuse or abuse with 95.7% sensitivity. Regardless of changes in the prevalence of opioid misuse or abuse, the sensitivity of POR remained >95%. The POR correctly stratifies patients into low-, moderate-, and high-risk categories to appropriately identify patients at need for additional guidance, monitoring, or treatment changes.

Transmission scenarios of major vector-borne diseases in Colombia, 1990-2016.

PubMed

Padilla, Julio César; Lizarazo, Fredy Eberto; Murillo, Olga Lucía; Mendigaña, Fernando Antonio; Pachón, Edwin; Vera, Mauricio Javier

2017-03-29

Introducción. Las enfermedades transmitidas por vectores representan más de 17 % de todas las enfermedades infecciosas y causan anualmente un millón de defunciones a nivel mundial. En Colombia, la malaria, el dengue, la enfermedad de Chagas y las leishmaniasis son condiciones endemoepidémicas persistentes.Objetivo. Determinar el comportamiento epidemiológico de las enfermedades transmitidas por vectores en zonas urbanas y rurales de Colombia entre 1990 y 2016.Materiales y métodos. Se hizo un estudio descriptivo del comportamiento epidemiológico de las principales enfermedades transmitidas por vectores en zonas urbanas y rurales de Colombia entre 1990 y 2016, con la información proveniente de fuentes oficiales secundarias.Resultados. En el periodo estudiado se registraron 5'360.134 casos de enfermedades transmitidas por vectores, de los cuales 54,7 % fueron de malaria y 24,9 % de dengue. Estos casos concentraron el 80 % de la carga acumulada de casos de enfermedades transmitidas por vectores. Las medianas de las tasas de incidencia fueron 1.371 y 188 por 100.00 habitantes para malaria y dengue, respectivamente. Además, los casos de chikungunya fueron 774.831 desde su introducción en el 2014 y, los de Zika, 117.674 desde su aparición en 2015. En las zonas rurales predominaron las enfermedades parasitarias transmitidas por vectores como la malaria, las leishmaniasis y la enfermedad de Chagas. A nivel urbano, predominaron el dengue, el chikungunya y el Zika.Conclusiones. La transmisión en Colombia de estas enfermedades es persistente en las zonas urbanas y en las rurales, y de tipo endemoepidémico en los casos de malaria, dengue, leishmaniasis y enfermedad de Chagas. Dicha transmisión se ha dado de manera focalizada y con patrones variables de intensidad. Asimismo, se mantienen las condiciones que han favorecido la transmisión emergente de nuevas arbovirosis.

76 FR 26241 - Certain Frozen Warmwater Shrimp From Thailand: Notice of Court Decision Not in Harmony With Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-06

... Shrimp From Thailand: Notice of Court Decision Not in Harmony With Final Results of Administrative Review... Thailand covering the period of review (POR) of February 1, 2006, through January 31, 2007. DATES... administrative review of certain frozen warmwater shrimp from Thailand covering the POR of February 1, 2006...

Proyecto Energético Palmdale; Decisión del Permiso Final

EPA Pesticide Factsheets

Proyecto Energético Palmdale: EPA Región 9 por el presente emite aviso de su decisión final, el cumplimiento con la Ley Federal de Aire Limpio, para la construcción de una planta generadora de electricidad de ciclo combinado y alimentada por gas natural

PubMed

Escandón-Nagel, Neli

2016-11-29

Introducción: si bien el Trastorno por Atracón es un trastorno de la conducta alimentaria que  no se da exclusivamente en personas obesas, es más común en este grupo que en sujetos con normopeso, sin embargo no todas las personas con malnutrición por exceso presentan Trastorno por Atracón. Objetivo: identificar el conocimiento actual respecto a las diferencias y semejanzas existentes entre personas con malnutrición por exceso con y sin Trastorno por Atracón.Método: para lograr el objetivo anterior, se realizó una revisión de artículos científicos en torno al tema.Resultados: primero se analizó la comorbilidad psicopatológica en obesidad y después se detectaron similitudes y diferencias entre los grupos de interés, tanto en sintomatología general, como así también en sintomatología de la conducta alimentaria. Además, se identificaron algunos aspectos controversiales, en que existe evidencia contradictoria respecto a la comparación intergrupal.Conclusión: de esta revisión se concluye que en el estudio de la obesidad se hace necesario conocer en mayor profundidad las características del subgrupo de pacientes que además presenta Trastorno por Atracón,  ya que estas personas poseen características distintivas cuyo conocimiento permitirá ofrecer tratamientos integrales más adecuados a las necesidades de los pacientes, lo que posibilitará, en consecuencia, diseñar intervenciones más eficaces.

[Not Available].

PubMed

Latorre-Román, Pedro Ángel; Martínez-López, Emilio José; Ruiz-Ariza, Alberto; Izquierdo-Rus, Tomás; Salas-Sánchez, Jesús; García-Pinillos, Felipe

2016-06-30

Objetivo: el objetivo de este estudio es evaluar las propiedades psicométricas del cuestionario de disfrute por el ejercicio físico (PACES) en adolescentes con sobrepeso y obesidad.Métodos: participaron 139 adolescentes con sobrepeso y obesidad: 91 niñas (edad = 13,85 ± 1,92 años; índice de masa corporal [IMC] = 26,83 ± 3,16 kg/m2) y 48 niños (edad = 14,29 ± 1,62 años; IMC = 28,31 ± 3,74 kg/m2). Para analizar el disfrute por la actividad física se empleó el cuestionario Physical Activity Enjoyment Scale (PACES).Resultados: los resultados del análisis factorial exploratorio y confirmatorio han mostrado una estructura de dos factores; a su vez el PACES presenta una consistencia interna muy alta (alfa de Cronbach = 0,908). La fiabilidad test-retest indica una buena concordancia temporal (Spearman rho = 0,815, p < 0,001). Por último, el PACES en adolescentes con sobrepeso y obesidad manifiesta una validez convergente adecuada con la intencionalidad de ser activo (MIFA), la atracción por la actividad física (CAPA), la resistencia cardiorrespiratoria y los pliegues suprailiacoy subescapular.Conclusión: los resultados confirman que el PACES es una medida válida y fiable del disfrute por la actividad física en adolescentes con sobrepeso y obesidad. El disfrute por la actividad física puede ser relevante en la participación de los adolescentes con sobrepeso y obesidad en estas actividades.

LIL3, a Light-Harvesting Complex Protein, Links Terpenoid and Tetrapyrrole Biosynthesis in Arabidopsis thaliana1[OPEN

PubMed Central

Rothbart, Maxi; Herbst, Josephine; Wittmann, Daniel; Gruhl, Kirsten

2017-01-01

The LIL3 protein of Arabidopsis (Arabidopsis thaliana) belongs to the light-harvesting complex (LHC) protein family, which also includes the light-harvesting chlorophyll-binding proteins of photosystems I and II, the early-light-inducible proteins, PsbS involved in nonphotochemical quenching, and the one-helix proteins and their cyanobacterial homologs designated high-light-inducible proteins. Each member of this family is characterized by one or two LHC transmembrane domains (referred to as the LHC motif) to which potential functions such as chlorophyll binding, protein interaction, and integration of interacting partners into the plastid membranes have been attributed. Initially, LIL3 was shown to interact with geranylgeranyl reductase (CHLP), an enzyme of terpene biosynthesis that supplies the hydrocarbon chain for chlorophyll and tocopherol. Here, we show another function of LIL3 for the stability of protochlorophyllide oxidoreductase (POR). Multiple protein-protein interaction analyses suggest the direct physical interaction of LIL3 with POR but not with chlorophyll synthase. Consistently, LIL3-deficient plants exhibit substantial loss of POR as well as CHLP, which is not due to defective transcription of the POR and CHLP genes but to the posttranslational modification of their protein products. Interestingly, in vitro biochemical analyses provide novel evidence that LIL3 shows high binding affinity to protochlorophyllide, the substrate of POR. Taken together, this study suggests a critical role for LIL3 in the organization of later steps in chlorophyll biosynthesis. We suggest that LIL3 associates with POR and CHLP and thus contributes to the supply of the two metabolites, chlorophyllide and phytyl pyrophosphate, required for the final step in chlorophyll a synthesis. PMID:28432258

Sunburn and sun-protective behaviors among adults with and without previous nonmelanoma skin cancer (NMSC): A population-based study.

PubMed

Fischer, Alexander H; Wang, Timothy S; Yenokyan, Gayane; Kang, Sewon; Chien, Anna L

2016-08-01

Individuals with previous nonmelanoma skin cancer (NMSC) are at increased risk for subsequent skin cancer, and should therefore limit ultraviolet exposure. We sought to determine whether individuals with previous NMSC engage in better sun protection than those with no skin cancer history. We pooled self-reported data (2005 and 2010 National Health Interview Surveys) from US non-Hispanic white adults (758 with and 34,161 without previous NMSC). We calculated adjusted prevalence odds ratios (aPOR) and 95% confidence intervals (CI), taking into account the complex survey design. Individuals with previous NMSC versus no history of NMSC had higher rates of frequent use of shade (44.3% vs 27.0%; aPOR 1.41; 95% CI 1.16-1.71), long sleeves (20.5% vs 7.7%; aPOR 1.55; 95% CI 1.21-1.98), a wide-brimmed hat (26.1% vs 10.5%; aPOR 1.52; 95% CI 1.24-1.87), and sunscreen (53.7% vs 33.1%; aPOR 2.11; 95% CI 1.73-2.59), but did not have significantly lower odds of recent sunburn (29.7% vs 40.7%; aPOR 0.95; 95% CI 0.77-1.17). Among those with previous NMSC, recent sunburn was inversely associated with age, sun avoidance, and shade but not sunscreen. Self-reported cross-sectional data and unavailable information quantifying regular sun exposure are limitations. Physicians should emphasize sunburn prevention when counseling patients with previous NMSC, especially younger adults, focusing on shade and sun avoidance over sunscreen. Copyright © 2016 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

LIL3, a Light-Harvesting Complex Protein, Links Terpenoid and Tetrapyrrole Biosynthesis in Arabidopsis thaliana.

PubMed

Hey, Daniel; Rothbart, Maxi; Herbst, Josephine; Wang, Peng; Müller, Jakob; Wittmann, Daniel; Gruhl, Kirsten; Grimm, Bernhard

2017-06-01

The LIL3 protein of Arabidopsis ( Arabidopsis thaliana ) belongs to the light-harvesting complex (LHC) protein family, which also includes the light-harvesting chlorophyll-binding proteins of photosystems I and II, the early-light-inducible proteins, PsbS involved in nonphotochemical quenching, and the one-helix proteins and their cyanobacterial homologs designated high-light-inducible proteins. Each member of this family is characterized by one or two LHC transmembrane domains (referred to as the LHC motif) to which potential functions such as chlorophyll binding, protein interaction, and integration of interacting partners into the plastid membranes have been attributed. Initially, LIL3 was shown to interact with geranylgeranyl reductase (CHLP), an enzyme of terpene biosynthesis that supplies the hydrocarbon chain for chlorophyll and tocopherol. Here, we show another function of LIL3 for the stability of protochlorophyllide oxidoreductase (POR). Multiple protein-protein interaction analyses suggest the direct physical interaction of LIL3 with POR but not with chlorophyll synthase. Consistently, LIL3-deficient plants exhibit substantial loss of POR as well as CHLP, which is not due to defective transcription of the POR and CHLP genes but to the posttranslational modification of their protein products. Interestingly, in vitro biochemical analyses provide novel evidence that LIL3 shows high binding affinity to protochlorophyllide, the substrate of POR. Taken together, this study suggests a critical role for LIL3 in the organization of later steps in chlorophyll biosynthesis. We suggest that LIL3 associates with POR and CHLP and thus contributes to the supply of the two metabolites, chlorophyllide and phytyl pyrophosphate, required for the final step in chlorophyll a synthesis. © 2017 American Society of Plant Biologists. All Rights Reserved.

Faecal calprotectin and magnetic resonance imaging in detecting Crohn's disease endoscopic postoperative recurrence.

PubMed

Baillet, Pierre; Cadiot, Guillaume; Goutte, Marion; Goutorbe, Felix; Brixi, Hedia; Hoeffel, Christine; Allimant, Christophe; Reymond, Maud; Obritin-Guilhen, Hélène; Magnin, Benoit; Bommelaer, Gilles; Pereira, Bruno; Hordonneau, Constance; Buisson, Anthony

2018-02-07

To assess magnetic resonance imaging (MRI) and faecal calprotectin to detect endoscopic postoperative recurrence in patients with Crohn's disease (CD). From two tertiary centers, all patients with CD who underwent ileocolonic resection were consecutively and prospectively included. All the patients underwent MRI and endoscopy within the first year after surgery or after the restoration of intestinal continuity [median = 6 mo (5.0-9.3)]. The stools were collected the day before the colonoscopy to evaluate faecal calprotectin level. Endoscopic postoperative recurrence (POR) was defined as Rutgeerts' index ≥ i2b. The MRI was analyzed independently by two radiologists blinded from clinical data. Apparent diffusion coefficient (ADC) was lower in patients with endoscopic POR compared to those with no recurrence (2.03 ± 0.32 vs 2.27 ± 0.38 × 10 -3 mm²/s, P = 0.032). Clermont score (10.4 ± 5.8 vs 7.4 ± 4.5, P = 0.038) and relative contrast enhancement (RCE) (129.4% ± 62.8% vs 76.4% ± 32.6%, P = 0.007) were significantly associated with endoscopic POR contrary to the magnetic resonance index of activity (MaRIA) (7.3 ± 4.5 vs 4.8 ± 3.7; P = 0.15) and MR scoring system ( P = 0.056). ADC < 2.35 × 10 -3 mm²/s [sensitivity = 0.85, specificity = 0.65, positive predictive value (PPV) = 0.85, negative predictive value (NPV) = 0.65] and RCE > 100% (sensitivity = 0.75, specificity = 0.81, PPV = 0.75, NPV = 0.81) were the best cut-off values to identify endoscopic POR. Clermont score > 6.4 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74), MaRIA > 3.76 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74) and a MR scoring system ≥ MR1 (sensitivity = 0.54, specificity = 0.82, PPV = 0.70, and NPV = 0.70) demonstrated interesting performances to detect endoscopic POR. Faecal calprotectin values were significantly higher in patients with endoscopic POR (114 ± 54.5 μg/g vs 354.8 ± 432.5 μg/g; P = 0.0075). Faecal calprotectin > 100 �

Faecal calprotectin and magnetic resonance imaging in detecting Crohn’s disease endoscopic postoperative recurrence

PubMed Central

Baillet, Pierre; Cadiot, Guillaume; Goutte, Marion; Goutorbe, Felix; Brixi, Hedia; Hoeffel, Christine; Allimant, Christophe; Reymond, Maud; Obritin-Guilhen, Hélène; Magnin, Benoit; Bommelaer, Gilles; Pereira, Bruno; Hordonneau, Constance; Buisson, Anthony

2018-01-01

AIM To assess magnetic resonance imaging (MRI) and faecal calprotectin to detect endoscopic postoperative recurrence in patients with Crohn’s disease (CD). METHODS From two tertiary centers, all patients with CD who underwent ileocolonic resection were consecutively and prospectively included. All the patients underwent MRI and endoscopy within the first year after surgery or after the restoration of intestinal continuity [median = 6 mo (5.0-9.3)]. The stools were collected the day before the colonoscopy to evaluate faecal calprotectin level. Endoscopic postoperative recurrence (POR) was defined as Rutgeerts’ index ≥ i2b. The MRI was analyzed independently by two radiologists blinded from clinical data. RESULTS Apparent diffusion coefficient (ADC) was lower in patients with endoscopic POR compared to those with no recurrence (2.03 ± 0.32 vs 2.27 ± 0.38 × 10-3 mm²/s, P = 0.032). Clermont score (10.4 ± 5.8 vs 7.4 ± 4.5, P = 0.038) and relative contrast enhancement (RCE) (129.4% ± 62.8% vs 76.4% ± 32.6%, P = 0.007) were significantly associated with endoscopic POR contrary to the magnetic resonance index of activity (MaRIA) (7.3 ± 4.5 vs 4.8 ± 3.7; P = 0.15) and MR scoring system (P = 0.056). ADC < 2.35 × 10-3 mm²/s [sensitivity = 0.85, specificity = 0.65, positive predictive value (PPV) = 0.85, negative predictive value (NPV) = 0.65] and RCE > 100% (sensitivity = 0.75, specificity = 0.81, PPV = 0.75, NPV = 0.81) were the best cut-off values to identify endoscopic POR. Clermont score > 6.4 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74), MaRIA > 3.76 (sensitivity = 0.61, specificity = 0.82, PPV = 0.73, NPV = 0.74) and a MR scoring system ≥ MR1 (sensitivity = 0.54, specificity = 0.82, PPV = 0.70, and NPV = 0.70) demonstrated interesting performances to detect endoscopic POR. Faecal calprotectin values were significantly higher in patients with endoscopic POR (114 ± 54.5 μg/g vs 354.8 ± 432.5 μg/g; P = 0.0075). Faecal

76 FR 34296 - Proposed Collection; Comment Request for Forms 1040-PR and 1040-SS

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-13

... Form 1040-PR, Planilla para la Declaraci[oacute]n de la Contribuci[oacute]n Federal sobre el Trabajo... Trabajo por Cuenta Propia (Incluyendo el Cr[eacute]dito Tributario Adicional por Hijos para Residentes... Subtitle A, and provide credit to the taxpayer's social security account. Anejo H-PR is used to compute...

77 FR 77017 - Certain Orange Juice From Brazil: Notice of Court Decision Not in Harmony With Final Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

..., International Trade Administration, Department of Commerce. SUMMARY: On October 24, 2012, the United States... juice (OJ) from Brazil covering the period of review (POR) of March 1, 2008, through February 28, 2009... administrative review of OJ from Brazil covering the POR of March 1, 2008, through February 28, 2009. See Certain...

La EPA ayuda a restaurar el laboratorio de ciencias de Puerto Rico y las capacidades de monitorear la calidad del aire

EPA Pesticide Factsheets

La EPA continúa ayudando a Puerto Rico a responder tras los daños causados por los huracanes Irma y María. La EPA, conforme a una misión asignada por FEMA, y en estrecha cooperación con el gobierno de Puerto Rico, se encuentra apoya

Two dimensional self-assembly zinc porphyrins and zinc phthalocyanines heterojunctions with record high power conversion efficiencies.

PubMed

Yu, Junting; Jiang, Zhou; Hao, Yifan; Zhu, Qianhong; Zhao, Mingliang; Jiang, Xue; Zhao, Jijun

2018-05-15

Compared to inorganic solar cells, the power conversion efficiencies (PCEs) of organic solar cells are much lower, but they are compensated by many merits such as lower cost, less weight, and tunable structures, making them prospective for further applications. Porphyrin and phthalocyanine are the two most significant materials for organic solar cells due to their strong light-absorbing properties and semiconductor characteristics. However, there is little research on the 2D heterojunction solar cells based on these two materials, meanwhile the PCEs of them are still low. Here we have self-assembled several 2D Zinc-porphyrins (ZnPors) and performed first-principles simulation to demonstrate their good stability, suitable light harvesting, and high charge carrier mobility. By perfectly matching lattice constants and band levels between those 2D ZnPors and our previous proposed ZnPcs, eleven type-II organic heterojunctions are constructed to further improve their charge separation capability. Those advantages endow 2D ZnPors and ZnPcs appreciable PCEs for solar cell. Among them, the theoretical PCE of 2D ZnPors/ZnPcs heterojunctions achieves as high as 19.84%, which prevails all reported organic solar cells, and even approaches the PCEs of inorganic solar cells. These results indicate that our 2D ZnPors and 2D ZnPcs are good candidate materials for future organic solar cells. © 2018 IOP Publishing Ltd.

Two dimensional self-assembly zinc porphyrin and zinc phthalocyanine heterojunctions with record high power conversion efficiencies

NASA Astrophysics Data System (ADS)

Yu, Junting; Jiang, Zhou; Hao, Yifan; Zhu, Qianhong; Zhao, Mingliang; Jiang, Xue; Zhao, Jijun

2018-06-01

Compared to inorganic solar cells, the power conversion efficiencies (PCEs) of organic solar cells are much lower, but they are compensated by many merits such as lower cost, less weight, and tunable structures, making them prospective for further applications. Porphyrin and phthalocyanine are the two most significant materials for organic solar cells due to their strong light-absorbing properties and semiconductor characteristics. However, there is little research on the 2D heterojunction solar cells based on these two materials, meanwhile the PCEs of them are still low. Here we have self-assembled several 2D zinc porphyrins (ZnPors) and performed first-principles simulation to demonstrate their good stability, suitable light harvesting, and high charge carrier mobility. By perfectly matching lattice constants and molecular energy levels between those 2D ZnPors and our previous proposed zinc phthalocyanines (ZnPcs), 11 type-II organic heterojunctions are constructed to further improve their charge separation capability. Those advantages endow 2D ZnPors and ZnPcs appreciable PCEs for solar cells. Among them, the theoretical PCE of 2D ZnPors/ZnPcs heterojunctions achieves as high as 19.84%, which exceeds all reported organic solar cells, and even approaches the PCEs of inorganic solar cells. These results indicate that our 2D ZnPors and 2D ZnPcs are good candidate materials for future organic solar cells.

78 FR 79665 - Welded Carbon Steel Standard Pipe and Tube Products From Turkey: Final Results of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-31

... Pipe and Tube Products From Turkey: Final Results of Antidumping Duty Administrative Review; 2011-2012... pipe and tube products (welded pipe and tube) from Turkey.\\1\\ The period of review (POR) is May 1, 2011... during the POR.\\2\\ \\1\\ See Welded Carbon Steel Standard Pipe and Tube Products from Turkey: Preliminary...

Differentiation‐associated urothelial cytochrome P450 oxidoreductase predicates the xenobiotic‐metabolizing activity of “luminal” muscle‐invasive bladder cancers

PubMed Central

Arlt, Volker M.; Indra, Radek; Joel, Madeleine; Stiborová, Marie; Eardley, Ian; Ahmad, Niaz; Otto, Wolfgang; Burger, Maximilian; Rubenwolf, Peter; Phillips, David H.; Southgate, Jennifer

2018-01-01

Extra‐hepatic metabolism of xenobiotics by epithelial tissues has evolved as a self‐defence mechanism but has potential to contribute to the local activation of carcinogens. Bladder epithelium (urothelium) is bathed in excreted urinary toxicants and pro‐carcinogens. This study reveals how differentiation affects cytochrome P450 (CYP) activity and the role of NADPH:P450 oxidoreductase (POR). CYP1A1 and CYP1B1 transcripts were inducible in normal human urothelial (NHU) cells maintained in both undifferentiated and functional barrier‐forming differentiated states in vitro. However, ethoxyresorufin O‐deethylation (EROD) activity, the generation of reactive BaP metabolites and BaP‐DNA adducts, were predominantly detected in differentiated NHU cell cultures. This gain‐of‐function was attributable to the expression of POR, an essential electron donor for all CYPs, which was significantly upregulated as part of urothelial differentiation. Immunohistology of muscle‐invasive bladder cancer (MIBC) revealed significant overall suppression of POR expression. Stratification of MIBC biopsies into “luminal” and “basal” groups, based on GATA3 and cytokeratin 5/6 labeling, showed POR over‐expression by a subgroup of the differentiated luminal tumors. In bladder cancer cell lines, CYP1‐activity was undetectable/low in basal PORlo T24 and SCaBER cells and higher in the luminal POR over‐expressing RT4 and RT112 cells than in differentiated NHU cells, indicating that CYP‐function is related to differentiation status in bladder cancers. This study establishes POR as a predictive biomarker of metabolic potential. This has implications in bladder carcinogenesis for the hepatic versus local activation of carcinogens and as a functional predictor of the potential for MIBC to respond to prodrug therapies. PMID:29323757

Association of low dietary intake of fiber and liquids with constipation: evidence from the National Health and Nutrition Examination Survey.

PubMed

Markland, Alayne D; Palsson, Olafur; Goode, Patricia S; Burgio, Kathryn L; Busby-Whitehead, Jan; Whitehead, William E

2013-05-01

Epidemiological studies support an association of self-defined constipation with fiber and physical activity, but not liquid intake. The aims of this study were to assess the prevalence and associations of dietary fiber and liquid intake to constipation. Analyses were based on data from 10,914 adults (≥20 years) from the 2005-2008 cycles of the National Health and Nutrition Examination Surveys. Constipation was defined as hard or lumpy stools (Bristol Stool Scale type 1 or 2) as the "usual or most common stool type." Dietary fiber and liquid intake from total moisture content were obtained from dietary recall. Co-variables included: age, race, education, poverty income ratio, body mass index, self-reported general health status, chronic illnesses, and physical activity. Prevalence estimates and prevalence odds ratios (POR) were analyzed in adjusted multivariable models using appropriate sampling weights. Overall, 9,373 (85.9%) adults (4,787 women and 4,586 men) had complete stool consistency and dietary data. Constipation rates were 10.2% (95% confidence interval (CI): 9.6, 10.9) for women and 4.0% (95% CI: 3.2, 5.0) for men (P<.001). After multivariable adjustment, low liquid consumption remained a predictor of constipation among women (POR: 1.3, 95% CI: 1.0, 1.6) and men (POR: 2.4, 95% CI: 1.5, 3.9); however, dietary fiber was not a predictor. Among women, African-American race/ethnicity (POR: 1.4, 95% CI: 1.0, 1.9), being obese (POR: 0.7, 95% CI: 0.5,0.9), and having a higher education level (POR: 0.8, 95% CI: 0.7, 0.9) were significantly associated with constipation. The findings support clinical recommendations to treat constipation with increased liquid, but not fiber or exercise.

Association of Low Dietary Intake of Fiber and Liquids with Constipation: Evidence from the National Health and Nutrition Examination Survey (NHANES)

PubMed Central

Markland, Alayne D.; Palsson, Olafur; Goode, Patricia S.; Burgio, Kathryn L.; Busby-Whitehead, Jan; Whitehead, William E.

2013-01-01

Objective Epidemiological studies support an association of self-defined constipation with fiber and physical activity, but not liquid intake. The aims of this study were to assess the prevalence and associations of dietary fiber and liquid intake to constipation. Methods Analyses were based on data from 10,914 adults (≥20 years) from the 2005-2008 cycles of the National Health and Nutrition Examination Surveys (NHANES). Constipation was defined as hard or lumpy stools (Bristol Stool Scale types 1 or 2) as the “usual or most common stool type.” Dietary fiber and liquid intake from total moisture content were obtained from dietary recall. Co-variables included: age, race, education, poverty income ratio, body mass index, self-reported general health status, chronic illnesses, and physical activity. Prevalence estimates and prevalence odds ratios (POR) were analyzed in adjusted multivariable models using appropriate sampling weights. Results Overall, 9,373 (85.9%) adults (4,787 women and 4,586 men) had complete stool consistency and dietary data. Constipation rates were 10.2% (95% CI: 9.6,10.9) for women and 4.0 (95% CI: 3.2,5.0) for men (p<.001). After multivariable adjustment, low liquid consumption remained a predictor of constipation among women (POR: 1.3, 95% CI: 1.0,1.6) and men (POR: 2.4, 95% CI: 1.5,3.9); however, dietary fiber was not a predictor. Among women, African-American race/ethnicity (POR: 1.4, 95% CI: 1.0,1.9), being obese (POR: 0.7, 95% CI: 0.5,0.9), and having a higher education level (POR: 0.8, 95% CI: 0.7,0.9) were significantly associated with constipation. Conclusions The findings support clinical recommendations to treat constipation with increased liquid, but not fiber or exercise. PMID:23567352

Factors associated with the incidence of pressure ulcer during hospital stay.

PubMed

Matozinhos, Fernanda Penido; Velasquez-Melendez, Gustavo; Tiensoli, Sabrina Daros; Moreira, Alexandra Dias; Gomes, Flávia Sampaio Latini

2017-05-25

Estimating the incidence rate of pressure ulcers and verifying factors associated with this occurrence in a cohort of hospitalized patients. This is a cohort study in which the considered outcome was the time until pressure ulcer occurrence. Estimated effect of the variables on the cumulative incidence ratio of the outcome was performed using the Cox proportional hazards model. Variable selection occurred via the Logrank hypothesis test. The sample consisted of 442 adults, with 25 incidents of pressure ulcers. Patients with high scores on the Braden scale presented a higher risk of pressure ulcer incidence when compared to those classified into the low score category. These results reinforce the importance of using the Braden Scale to assist in identifying patients more likely to develop pressure ulcers. Estimar a taxa de incidência de úlcera por pressão e verificar fatores associados a essa ocorrência em uma coorte de pacientes hospitalizados. Trata-se de estudo de coorte no qual o desfecho foi a ocorrência da úlcera por pressão. A estimativa do efeito das variáveis para a proporção de incidência acumulada do desfecho foi realizada utilizando o modelo de riscos proporcionais de Cox. A seleção das variáveis ocorreu por meio do teste de hipóteses Logrank. A amostra foi composta de 442 adultos, com 25 casos incidentes de úlcera por pressão. Pacientes com altos escores na escala de Braden apresentaram maior risco de incidência de úlcera por pressão quando comparados com aqueles classificados na categoria de baixo escore. Os resultados reforçam a importância do uso da Escala de Braden para auxiliar na identificação dos pacientes com maior probabilidade de desenvolver úlcera por pressão.

Missed Opportunities for Human Immunodeficiency Virus and Syphilis Testing Among Men Who Have Sex With Men in China: A Cross-Sectional Study.

PubMed

Ong, Jason J; Fu, Hongyun; Pan, Stephen; Smith, M Kumi; Wu, Dan; Wei, Chongyi; Cao, Bolin; Ma, Wei; Yang, Ligang; Tang, Weiming; Tucker, Joseph D

2018-06-01

Men who have sex with men (MSM) are at high risk of human immunodeficiency virus (HIV)/syphilis. To inform strategies for dual testing, we describe patterns of HIV/syphilis testing, and examine factors associated with never testing for HIV/syphilis in China. An online survey (2016) was completed by MSM from 8 cities: men born biologically male, 16 years or older, and had sex with another man at least once during their lifetime. Demographic, sexual behavioral, and HIV/syphilis testing data were collected. Multivariable multinomial logistic regression identified characteristics associated with men who never tested for HIV/syphilis compared with men who ever tested for both infections. Overall, 2105 men participated. Among them, 35.1% (738/2105) never tested for HIV/syphilis, and in those ever tested for HIV, only half (54.0%, 709/1312) had tested for syphilis. Relative to men who had ever tested for both infections, those with increased probability of never testing for HIV/syphilis include non-gay sexual identity (prevalence odds ratio [POR] 1.86; 95% confidence interval [CI], 1.45-2.37), not disclosed their sexuality/sexual history with men other than their regular partner (POR, 2.22; 95% CI, 1.75-2.78]) or with health professionals (POR, 11.11; 95% CI, 7.69-14.29), no condomless sex with casual partners in the last 3 months (POR, 1.89; 95% CI, 1.37-2.56), no community engagement in sexual health (POR, 15.16; 95% CI, 9.40-24.45), and mainly met partners offline (POR, 1.49; 95% CI, 1.16-1.92). There are significant gaps in lifetime testing for HIV/syphilis among Chinese MSM. Strategies to target never testers and integrate syphilis testing within HIV testing services are urgently needed. Future opportunities include point-of-care dual test kits, and testing in China's expanding primary healthcare system.

Does open-air exposure to volatile organic compounds near a plastic recycling factory cause health effects?

PubMed

Yorifuji, Takashi; Noguchi, Miyuki; Tsuda, Toshihide; Suzuki, Etsuji; Takao, Soshi; Kashima, Saori; Yanagisawa, Yukio

2012-01-01

After a plastic reprocessing factory began to operate in August 2004, the residents around the factory in Neyagawa, Osaka, Japan, began to complain of symptoms. Therefore, we conducted an exposure assessment and a population-based epidemiological study in 2006. To assess exposure, volatile organic compounds (VOCs) and total VOCs were measured at two locations in the vicinity of the factory. In the population-based study, a total of 3,950 residents were targeted. A self-administered questionnaire was used to collect information about subjects' mucocutaneous or respiratory symptoms. Using logistic regression models, we compared the prevalence of symptoms in July 2006 by employing the farthest area from the factory as a reference, and prevalence odds ratios (PORs) and their 95% confidence intervals (CIs) were estimated. The concentration of total VOCs was higher in the vicinity of the factory. The prevalence of mucocutaneous and respiratory symptoms was the highest among the residents in the closest area to the factory. Some symptoms were significantly increased among the residents within 500 m of the factory compared with residents of an area 2800 m from the factory: e.g., sore throat (POR=3.2, 95% CI: 1.3-8.0), eye itch (POR=3.0, 95% CI: 1.5-6.0), eye discharge (POR=6.0, 95% CI: 2.3-15.9), eczema (POR=3.0, 95% CI: 1.1-7.9) and sputum (POR=2.4, 95% CI: 1.1-5.1). Despite of the limitations of this study, these results imply a possible association of open-air VOCs with mucocutaneous and respiratory symptoms. Because this kind of plasticre cycling factory only recently came into operation, more attention should be paid to the operation of plastic recycling factories in the environment.

PubMed

Dipierri, José Edgardo; Bronberg, Rubén Adrian

2017-09-08

Debido al incremento de casos de microcefalia por virus Zika en Brasil el Ministerio de Salud de Argentina recomienda incrementar la vigilancia de esta malformación. A fin de profundizar el conocimiento del comportamiento epidemiológico de microcefalia en el país se analiza la mortalidad infantil por microcefalia entre 1998-2012. Los datos proceden de la Dirección de Estadísticas e Información de Salud (DEIS). Se calculó por provincias y regiones la tasa de mortalidad infantil por microcefalia (TMI-M) y se realizó un análisis de agrupamiento a nivel departamental. Las tasas más elevadas se observaron en las regiones y provincias del norte del país. La distribución espacial de la TMI-M guarda relación con las prevalencias de microcefalia en recién nacidos. Esta distribución se relaciona con la mayor pobreza y consanguinidad del norte de la Argentina, factores sinérgicos predisponentes de la ocurrencia de malformaciones congénitas en general y de microcefalia en particular.

Long-term follow-up of a female with congenital adrenal hyperplasia due to P450-oxidoreductase deficiency.

PubMed

Bonamichi, Beatriz D S F; Santiago, Stella L M; Bertola, Débora R; Kim, Chong A; Alonso, Nivaldo; Mendonca, Berenice B; Bachega, Tania A S S; Gomes, Larissa G

2016-10-01

P450 oxidoreductase deficiency (PORD) is a variant of congenital adrenal hyperplasia that is caused by POR gene mutations. The POR gene encodes a flavor protein that transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH) to all microsomal cytochrome P450 type II (including 21-hydroxylase, 17α-hydroxylase 17,20 lyase and aromatase), which is fundamental for their enzymatic activity. POR mutations cause variable impairments in steroidogenic enzyme activities that result in wide phenotypic variability ranging from 46,XX or 46,XY disorders of sexual differentiation, glucocorticoid deficiency, with or without skeletal malformations similar to Antley-Bixler syndrome to asymptomatic newborns diagnosed during neonatal screening test. Little is known about the PORD long-term evolution. We described a 46,XX patient with mild atypical genitalia associated with severe bone malformation, who was diagnosed after 13 years due to sexual infantilism. She developed large ovarian cysts and late onset adrenal insufficiency during follow-up, both of each regressed after hormone replacement therapies. We also described a late surgical approach for the correction of facial hypoplasia in a POR patient.

Observational study to calculate addictive risk to opioids: a validation study of a predictive algorithm to evaluate opioid use disorder

PubMed Central

Brenton, Ashley; Richeimer, Steven; Sharma, Maneesh; Lee, Chee; Kantorovich, Svetlana; Blanchard, John; Meshkin, Brian

2017-01-01

Background Opioid abuse in chronic pain patients is a major public health issue, with rapidly increasing addiction rates and deaths from unintentional overdose more than quadrupling since 1999. Purpose This study seeks to determine the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated single-nucleotide polymorphisms (SNPs). Patients and methods The Proove Opioid Risk (POR) algorithm determines the predictability of aberrant behavior to opioids using a comprehensive scoring algorithm incorporating phenotypic risk factors and neuroscience-associated SNPs. In a validation study with 258 subjects with diagnosed opioid use disorder (OUD) and 650 controls who reported using opioids, the POR successfully categorized patients at high and moderate risks of opioid misuse or abuse with 95.7% sensitivity. Regardless of changes in the prevalence of opioid misuse or abuse, the sensitivity of POR remained >95%. Conclusion The POR correctly stratifies patients into low-, moderate-, and high-risk categories to appropriately identify patients at need for additional guidance, monitoring, or treatment changes. PMID:28572737

[Not Available].

PubMed

Ortega, Rosa M

2016-07-19

El artículo de San Mauro y cols. profundiza en un tema de interés prioritario como es el estudio de los hábitos de ingesta de fluidos en personas de cuatro países: España, Portugal, México y Uruguay, para analizar si se cumplen (y si se conocen) las pautas de hidratación marcadas como adecuadas por organismos oficiales y, en concreto, por la EFSA. Es indudable la importancia de una correcta hidratación pues mientras que se puede vivir meses, o años, con una alimentación incorrecta, la deshidratación puede llevar a la muerte en un escaso periodo de tiempo. Por otra parte, un aporte ligeramente insuficiente de fluidos perjudica la salud, capacidad funcional y calidad de vida del individuo, por lo que debe ser evitada. Incluso algunos estudios encuentran hábitos y estilo de vida menos saludables en individuos con menor consumo de fluidos y pautas de hidratación más incorrectas.

Postinfectious bronchiolitis obliterans

PubMed

2018-06-01

La bronquiolitis obliterante es una enfermedad pulmonar crónica infrecuente y grave producto de una lesión del tracto respiratorio inferior. En nuestro país, es más frecuente observarla secundaria a una lesión viral grave, en especial, por adenovirus. La bronquiolitis obliterante se caracteriza por la oclusión parcial o total del lumen de los bronquiolos respiratorios y terminales por tejido inflamatorio y fibrosis, que produce la obstrucción crónica de la vía aérea. Este consenso discute el estado actual del conocimiento en las diferentes áreas de la bronquiolitis obliterante secundaria a una lesión infecciosa.

Mortalidade em florestas de Pinus palustris causada por tempestade de raios

Treesearch

Kenneth W. Outcalt; Jorge Paladino Corrêa de Lima; Jose Américo de Mello Filho

2002-01-01

The importance of lightning as an ignition source for the fire driven Pinus palustris ecosystem is widely recognized. Lightning also impacts this system on a smaller scale by causing individual tree mortality. The objective of this study was to determine the level of mortality due to lightning activity at the Department of Energy's Savannah...

Betavoltaic device in por-SiC/Si C-Nuclear Energy Converter

NASA Astrophysics Data System (ADS)

Akimchenko, Alina; Chepurnov, Victor; Dolgopolov, Mikhail; Gurskaya, Albina; Kuznetsov, Oleg; Mashnin, Alikhan; Radenko, Vitaliy; Radenko, Alexander; Surnin, Oleg; Zanin, George

2017-10-01

The miniature and low-power devices with long service life in hard operating conditions like the Carbon-14 beta-decay energy converters indeed as eternal resource for integrated MEMS and NEMS are considered. Authors discuss how to create the power supply for MEMS/NEMS devices, based on porous SiC/Si structure, which are tested to be used as the beta-decay energy converters of radioactive C-14 into electrical energy. This is based on the silicon carbide obtaining by self-organizing mono 3C-SiC endotaxy on the Si substrate. The new idea is the C-14 atoms including in molecules in the silicon carbide porous structure by this technology, which will increase the efficiency of the converter due to the greater intensity of electron-hole pairs generation rate in the space charge region. The synthesis of C-14 can be also performed by using the electronically controlled magneto-optic chamber.

Applying Cognitive Linguistics to Teaching the Spanish Prepositions "Por" and "Para"

ERIC Educational Resources Information Center

Lam, Yvonne

2009-01-01

L2 prepositions are traditionally taught in a non-explanatory manner by having students learn each use individually. This study examines the effectiveness of an alternative explanatory approach based on cognitive linguistics, which considers the multiple uses of a preposition as related. Consequently, learners can be shown a general schema that…

"Por Los Ojos De Madres": Latina Mothers' Understandings of College Readiness

ERIC Educational Resources Information Center

Cortez, Laura Jean; Martinez, Melissa Ann; Sáenz, Victor B.

2014-01-01

In this study, data from six focus groups with 30 Latina mothers in South Texas were analyzed utilizing a "funds of knowledge" approach to uncover their understandings of college readiness and their role in ensuring their children are college ready. Findings indicate that Latina mothers perceived college readiness in a holistic fashion,…

Intoxicação experimental por Niedenzuella stannea (Malpighiaceae) em ovinos

USDA-ARS?s Scientific Manuscript database

Niedenzuella stannea a sodium monofluoroacetate-containing plant cause of sudden death in cattle in southern Mato Grosso State. This study describes the toxicity and clinical and pathological findings of experimental poisoning by N. stannea in sheep. Fruits, mature leaves and young leaves of the pla...

Enfermedad diarreica aguda por Escherichia coli patógenas en Colombia

PubMed Central

Gómez-Duarte, Oscar G.

2014-01-01

Resumen Las cepas de E. coli patógenas intestinales son causas importantes de la enfermedad diarreica aguda (EDA) en niños menores de 5 años en América Latina, África y Asia y están asociadas a alta mortalidad en niños en las comunidades más pobres de África y el Sudeste Asiático. Estudios sobre el papel de las E. coli patógenas intestinales en la EDA infantil en Colombia y otros países de América Latina son limitados debido a la carencia de ensayos para detección de estos patógenos en los laboratorios clínicos de centros de salud. Estudios recientes han reportado la detección de E. coli patógenas intestinales en Colombia, siendo la E. coli enterotoxigénica la cepa más frecuentemente asociada a diarrea en niños menores de 5 años. Otros patógenos detectados en estos pacientes incluyen las E. coli enteroagregativa, enteropatógena, productora de toxina Shiga, y de adherencia difusa. Con base en estudios que reportan la presencia de E. coli productora de toxina Shiga y E. coli enteroagregativa en carnes y vegetales en supermercados, se cree que productos alimentarios contaminados contribuyen a la transmisión de estos patógenos y a la infección del huésped susceptible. Más estudios son necesarios para evaluar los mecanismos de transmisión, el impacto en la epidemiologia de la EDA, y las pautas de manejo y prevención de estos patógenos que afectan la población pediátrica en Colombia. PMID:25491457

Mirta Yáñez's Dystopic Vision of Havana

ERIC Educational Resources Information Center

González, Flora M.

2017-01-01

In her 2010 novel "Sangra por la herida," the Cuban novelist, poet, and essayist Mirta Yáñez constructs a panoramic view of metropolitan Havana, following the model of Latin American fiction starting in the 1980s based on a revised version of the detective novel. "Sangra por la herida" functions best as a narrative that…

Perception of recovery of households affected by 2008 Wenchuan earthquake: A structural equation model

PubMed Central

Lin, Le; Wang, Ying; Liu, Tianxue

2017-01-01

Much of the literature on recovery focuses on the economy, the physical environment and infrastructure at a macro level, which may ignore the personal experiences of affected individuals during recovery. This paper combines internal factors at a micro level and external factors at a macro level to model for understanding perception of recovery (PoR). This study focuses on areas devastated by the 2008 Wenchuan earthquake in China. With respect to three recovery-related aspects (house recovery condition (HRC), family recovery power (FRP) and reconstruction investment (RI)), structural equation modeling (SEM) was applied. It was found that the three aspects (FRP, HRC and RI) effectively explain how earthquake affected households perceive recovery. Internal factors associated with FRP contributed the most to favourable PoR, followed by external factors associated with HRC. Findings identified that for PoR the importance of active recovery within households outweighed an advantageous house recovery condition. At the same time, households trapped in unfavourable external conditions would invest more in housing recovery, which result in wealth accumulation and improved quality of life leading to a high level of PoR. In addition, schooling in households showed a negative effect on improving PoR. This research contributes to current debates around post-disaster permanent housing policy. It is implied that a one-size-fits-all policy in disaster recovery may not be effective and more specific assistance should be provided to those people in need. PMID:28854217

See the World on the Internet: Tips for Parents of Young Readers--and "Surfers" = Vea el mundo por Internet: Ideas por padres de jovenes lectores y exploradores.

ERIC Educational Resources Information Center

Moss, Jeanette

Regardless of whether a parent has Internet access at home, it is essential that parents learn with their children and be aware of where their travels on the Internet are taking them. Many libraries have Internet workshops for parents or children or both. In the excitement of looking at sites, children may not even realize they are reading. Many…

Hydrocarbon oxidation by beta-halogenated dioxoruthenium(VI) porphyrin complexes: effect of reduction potential (RuVI/V) and C-H bond-dissociation energy on rate constants.

PubMed

Che, Chi-Ming; Zhang, Jun-Long; Zhang, Rui; Huang, Jie-Sheng; Lai, Tat-Shing; Tsui, Wai-Man; Zhou, Xiang-Ge; Zhou, Zhong-Yuan; Zhu, Nianyong; Chang, Chi Kwong

2005-11-18

beta-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru(VI)(F(28)-tpp)O(2)] [F(28)-tpp=2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(VI)(beta-Br(8)-tmp)O(2)] [beta-Br(8)-tmp=2,3,7,8,12,13,17,18-octabromo-5,10,15,20- tetrakis(2,4,6-trimethylphenyl)porphyrinato(2-)] were prepared from reactions of [Ru(II)(por)(CO)] [por=porphyrinato(2-)] with m-chloroperoxybenzoic acid in CH(2)Cl(2). Reactions of [Ru(VI)(por)O(2)] with excess PPh(3) in CH(2)Cl(2) gave [Ru(II)(F(20)-tpp)(PPh(3))(2)] [F(20)-tpp=5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(II)(F(28)-tpp)(PPh(3))(2)]. The structures of [Ru(II)(por)(CO)(H(2)O)] and [Ru(II)(por)(PPh(3))(2)] (por=F(20)-tpp, F(28)-tpp) were determined by X-ray crystallography, revealing the effect of beta-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru(VI)(F(20)-tpp)O(2)] shows a Ru=O bond length of 1.718(3) A. Electrochemical reduction of [Ru(VI)(por)O(2)] (Ru(VI) to Ru(V)) is irreversible or quasi-reversible, with the E(p,c)(Ru(VI/V)) spanning -0.31 to -1.15 V versus Cp(2)Fe(+/0). Kinetic studies were performed for the reactions of various [Ru(VI)(por)O(2)], including [Ru(VI)(F(28)-tpp)O(2)] and [Ru(VI)(beta-Br(8)-tmp)O(2)], with para-substituted styrenes p-X-C(6)H(4)CH=CH(2) (X=H, F, Cl, Me, MeO), cis- and trans-beta-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k(2)) obtained for the hydrocarbon oxidations by [Ru(VI)(F(28)-tpp)O(2)] are up to 28-fold larger than by [Ru(VI)(F(20)-tpp)O(2)]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru(VI)(F(28)-tpp)O(2)] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k(2) values for the oxidation of styrene and

JIATF-SWB: Building an Operational Bridge for the Southwest Border

DTIC Science & Technology

2011-04-12

mexican_cartels_integr.htm. (accessed 20 March 2011). 4 Office of the President. “Obtener la base de datos de Fallecimientos ocurridos por presunta rivalidad...Obtener la base de datos de Fallecimientos ocurridos por presunta rivalidad delincuencial en el periodo diciembre 2006 a diciembre 2010... basing , technical, intelligence, and training support to JIATF-SWB. 15. SUBJECT TERMS Mexico, Southwest Border, USNORTHCOM, Interagency, 16

European Command Hazardous Material Management Program

DTIC Science & Technology

2011-05-12

cause the hazard>; ES: Puede provocar cáncer <indíquese la vía de exposición si se ha demostrado concluyentemente que el peligro no se produce por...demostrado concluyentemente que el peligro no se produce por ninguna otra vía>. H302: Harmful if swallowed; ES: Nocivo en caso de ingestión. H317: May