Virulence meets metabolism: Cra and KdpE gene regulation in enterohemorrhagic Escherichia coli.

Science.gov (United States)

Njoroge, Jacqueline W; Nguyen, Y; Curtis, Meredith M; Moreira, Cristiano G; Sperandio, Vanessa

2012-10-16

Gastrointestinal (GI) bacteria sense diverse environmental signals as cues for differential gene regulation and niche adaptation. Pathogens such as enterohemorrhagic Escherichia coli (EHEC), which causes bloody diarrhea, use these signals for the temporal and energy-efficient regulation of their virulence factors. One of the main virulence strategies employed by EHEC is the formation of attaching and effacing (AE) lesions on enterocytes. Most of the genes necessary for the formation of these lesions are grouped within a pathogenicity island, the locus of enterocyte effacement (LEE), whose expression requires the LEE-encoded regulator Ler. Here we show that growth of EHEC in glycolytic environments inhibits the expression of ler and consequently all other LEE genes. Conversely, growth within a gluconeogenic environment activates expression of these genes. This sugar-dependent regulation is achieved through two transcription factors: KdpE and Cra. Both Cra and KdpE directly bind to the ler promoter, and Cra's affinity to this promoter is catabolite dependent. Moreover, we show that the Cra and KdpE proteins interact in vitro and that KdpE's ability to bind DNA is enhanced by the presence of Cra. Cra is important for AE lesion formation, and KdpE contributes to this Cra-dependent regulation. The deletion of cra and kdpE resulted in the ablation of AE lesions. One of the many challenges that bacteria face within the GI tract is to successfully compete for carbon sources. Linking carbon metabolism to the precise coordination of virulence expression is a key step in the adaptation of pathogens to the GI environment. IMPORTANCE An appropriate and prompt response to environmental cues is crucial for bacterial survival. Cra and KdpE are two proteins found in both nonpathogenic and pathogenic bacteria that regulate genes in response to differences in metabolite concentration. In this work, we show that, in the deadly pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7

Catabolite and Oxygen Regulation of Enterohemorrhagic Escherichia coli Virulence

Directory of Open Access Journals (Sweden)

Kimberly M. Carlson-Banning

2016-11-01

Full Text Available The biogeography of the gut is diverse in its longitudinal axis, as well as within specific microenvironments. Differential oxygenation and nutrient composition drive the membership of microbial communities in these habitats. Moreover, enteric pathogens can orchestrate further modifications to gain a competitive advantage toward host colonization. These pathogens are versatile and adept when exploiting the human colon. They expertly navigate complex environmental cues and interkingdom signaling to colonize and infect their hosts. Here we demonstrate how enterohemorrhagic Escherichia coli (EHEC uses three sugar-sensing transcription factors, Cra, KdpE, and FusR, to exquisitely regulate the expression of virulence factors associated with its type III secretion system (T3SS when exposed to various oxygen concentrations. We also explored the effect of mucin-derived nonpreferred carbon sources on EHEC growth and expression of virulence genes. Taken together, the results show that EHEC represses the expression of its T3SS when oxygen is absent, mimicking the largely anaerobic lumen, and activates its T3SS when oxygen is available through Cra. In addition, when EHEC senses mucin-derived sugars heavily present in the O-linked and N-linked glycans of the large intestine, virulence gene expression is initiated. Sugars derived from pectin, a complex plant polysaccharide digested in the large intestine, also increased virulence gene expression. Not only does EHEC sense host- and microbiota-derived interkingdom signals, it also uses oxygen availability and mucin-derived sugars liberated by the microbiota to stimulate expression of the T3SS. This precision in gene regulation allows EHEC to be an efficient pathogen with an extremely low infectious dose.

Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli Cells Artificially Internalized into Vegetable Seeds during Germination.

Science.gov (United States)

Liu, Da; Cui, Yue; Walcott, Ronald; Chen, Jinru

2018-01-01

Vegetable seeds contaminated with bacterial pathogens have been linked to fresh-produce-associated outbreaks of gastrointestinal infections. This study was undertaken to observe the physiological behavior of Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) cells artificially internalized into vegetable seeds during the germination process. Surface-decontaminated seeds of alfalfa, fenugreek, lettuce, and tomato were vacuum-infiltrated with four individual strains of Salmonella or EHEC. Contaminated seeds were germinated at 25°C for 9 days, and different sprout/seedling tissues were microbiologically analyzed every other day. The internalization of Salmonella and EHEC cells into vegetable seeds was confirmed by the absence of pathogens in seed-rinsing water and the presence of pathogens in seed homogenates after postinternalization seed surface decontamination. Results show that 317 (62%) and 343 (67%) of the 512 collected sprout/seedling tissue samples were positive for Salmonella and EHEC, respectively. The average Salmonella populations were significantly larger ( P seed coat tissues, followed by the root tissues, but the mean EHEC populations from all sampled tissue sections were statistically similar, except in pregerminated seeds. Three Salmonella and two EHEC strains had significantly larger cell populations on sprout/seedling tissues than other strains used in the study. Salmonella and EHEC populations from fenugreek and alfalfa tissues were significantly larger than those from tomato and lettuce tissues. The study showed the fate of internalized human pathogens on germinating vegetable seeds and sprout/seedling tissues and emphasized the importance of using pathogen-free seeds for sprout production. IMPORTANCE The internalization of microorganisms into vegetable seeds could occur naturally and represents a possible pathway of vegetable seed contamination by human pathogens. The present study investigated the ability of two important

Occurrence and characterization of Shiga toxin-producing Escherichia coli O157:H7 and other non-sorbitol-fermenting E. coli in cattle and humans in urban areas of Morogoro, Tanzania.

Science.gov (United States)

Lupindu, Athumani M; Olsen, John E; Ngowi, Helena A; Msoffe, Peter L M; Mtambo, Madundo M; Scheutz, Flemming; Dalsgaard, Anders

2014-07-01

Escherichia coli strains such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli, enterotoxigenic, attaching, and effacing E. coli, and enteroinvasive E. coli cause diarrhea in humans. Although other serotypes exist, the most commonly reported STEC in outbreaks is O157:H7. A cross-sectional study was conducted to isolate and characterize non-sorbitol-fermenting (NSF) E. coli O157:H7 from urban and periurban livestock settings of Morogoro, Tanzania. Human stool, cattle feces, and soil and water samples were collected. Observations and questionnaire interview studies were used to gather information about cattle and manure management practices in the study area. E. coli were isolated on sorbitol MacConkey agar and characterized by conventional biochemical tests. Out of 1049 samples, 143 (13.7%) yielded NSF E. coli. Serological and antimicrobial tests and molecular typing were performed to NSF E. coli isolates. These procedures detected 10 (7%) pathogenic E. coli including STEC (n=7), enteropathogenic E. coli (EPEC) (n=2), and attaching and effacing E. coli (A/EEC) (n=1) strains. The STEC strains had the ability to produce VT1 and different VT2 toxin subtypes that caused cytopathic effects on Vero cells. The prevalence of STEC in cattle was 1.6%, out of which 0.9% was serotype O157:H7 and the overall prevalence of diarrheagenic E. coli in cattle was 2.2%. The serotypes O157:H7, O142:H34, O113:H21, O+:H-, O+:H16, and O25:H4 were identified. One ESBL-producing isolate showed the MLST type ST131. To our knowledge, this is the first finding in Tanzania of this recently emerged worldwide pandemic clonal group, causing widespread antimicrobial-resistant infections, and adds knowledge of the geographical distribution of ST131. Cattle manure was indiscriminately deposited within residential areas, and there was direct contact between humans and cattle feces during manure handling. Cattle and manure management practices expose humans, animals, and the environment

Enterohemorrhagic Escherichia coli Hybrid Pathotype O80:H2 as a New Therapeutic Challenge

Science.gov (United States)

Soysal, Nurcan; Mariani-Kurkdjian, Patricia; Smail, Yasmine; Liguori, Sandrine; Gouali, Malika; Loukiadis, Estelle; Fach, Patrick; Bruyand, Mathias; Blanco, Jorge; Bidet, Philippe

2016-01-01

We describe the epidemiology, clinical features, and molecular characterization of enterohemorrhagic Escherichia coli (EHEC) infections caused by the singular hybrid pathotype O80:H2, and we examine the influence of antibiotics on Shiga toxin production. In France, during 2005–2014, a total of 54 patients were infected with EHEC O80:H2; 91% had hemolytic uremic syndrome. Two patients had invasive infections, and 2 died. All strains carried stx2 (variants stx2a, 2c, or 2d); the rare intimin gene (eae-ξ); and at least 4 genes characteristic of pS88, a plasmid associated with extraintestinal virulence. Similar strains were found in Spain. All isolates belonged to the same clonal group. At subinhibitory concentrations, azithromycin decreased Shiga toxin production significantly, ciprofloxacin increased it substantially, and ceftriaxone had no major effect. Antibiotic combinations that included azithromycin also were tested. EHEC O80:H2, which can induce hemolytic uremic syndrome complicated by bacteremia, is emerging in France. However, azithromycin might effectively combat these infections. PMID:27533474

Fructose production by Zymomonas mobilis in fed-batch culture with minimal sorbitol formation

Energy Technology Data Exchange (ETDEWEB)

Edye, L A; Johns, M R; Ewings, K N

1989-08-01

Fed-batch cultures of Zymomonas mobilis (UQM 2864), a mutant unable to metabolise fructose, grown on diluted sugar cane syrup (200 g/l sucrose) achieved yields of 90.5 g/l fructose and 48.3 g/l ethanol with minimal sorbitol formation and complete utilization of the substrate. The effect of inoculum size on sorbitol formation in the batch stage of fed-batch fermentation are reported. Fermentation of sucrose (350 g/l) supplemented with nutrients yielded 142 g/l fructose and 76.5 g/l ethanol. Some fructose product loss at high fructose concentrations was observed. The fed-batch fermentation process offers a method for obtaining high concentrations of fructose and ethanol from sucrose materials. (orig.).

N-chlorotaurine, a long-lived oxidant produced by human leukocytes, inactivates Shiga toxin of enterohemorrhagic Escherichia coli.

Directory of Open Access Journals (Sweden)

Christian Eitzinger

Full Text Available N-chlorotaurine (NCT, the main representative of long-lived oxidants produced by granulocytes and monocytes, is known to exert broad-spectrum microbicidal activity. Here we show that NCT directly inactivates Shiga toxin 2 (Stx2, used as a model toxin secreted by enterohemorrhagic Escherichia coli (EHEC. Bacterial growth and Stx2 production were both inhibited by 2 mM NCT. The cytotoxic effect of Stx2 on Vero cells was removed by ≥5.5 mM NCT. Confocal microscopy and FACS analyses showed that the binding of Stx2 to human kidney glomerular endothelial cells was inhibited, and no NCT-treated Stx2 entered the cytosol. Mass spectrometry displayed oxidation of thio groups and aromatic amino acids of Stx2 by NCT. Therefore, long-lived oxidants may act as powerful tools of innate immunity against soluble virulence factors of pathogens. Moreover, inactivation of virulence factors may contribute to therapeutic success of NCT and novel analogs, which are in development as topical antiinfectives.

Hemolytic-uremic syndrome with acute encephalopathy in a pregnant woman infected with epidemic enterohemorrhagic Escherichia coli: characteristic brain images and cytokine profiles.

Science.gov (United States)

Ito, M; Shiozaki, A; Shimizu, M; Saito, S

2015-05-01

A food-poisoning outbreak due to enterohemorrhagic Escherichia coli (EHEC) occurred in Toyama, Japan. The case of a 26-year-old pregnant woman with hemolytic-uremic syndrome who developed acute encephalopathy due to EHEC infection after eating raw meat is presented herein. On day 2 following admission, a cesarean section was performed because of a non-reassuring fetal status. Fecal bacterial culture confirmed an O111/O157 superinfection. Intensive care therapies including continuous hemodiafiltration and plasma exchange were performed. After the operation, the patient developed encephalopathy for which steroid pulse therapy was added. Her condition improved gradually and she was discharged 55 days after delivery. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Relative gene transcription and pathogenicity of enterohemorrhagic Escherichia coli after long-term adaptation to acid and salt stress

DEFF Research Database (Denmark)

Olesen, Inger; Jespersen, Lene

2010-01-01

Relative gene transcription and virulence potential, as measured by a Caco-2 adhesion assay, were investigated for three enterohemorrhagic Escherichia coli (EHEC) strains after long-term adaptation for 24 h to acid (BHI pH 5.5) and salt (BHI 4.5% (w/v) NaCl) stress. Five virulence genes (eae, lpf...... compared to EDL933 (O157:H7, raw hamburger). Long-term adaptation to salt stress significantly increased the adhesion of all three EHEC strains to Caco-2 compared to the non-stressed controls. The present study shows that long-term adaptation to food related stress factors such as acid and salt is capable...... of changing the relative transcription of important virulence and stress response genes and increasing the virulence potential as measured by adhesion to the human colonic epithelial cell line, Caco-2....

Enterohemorrhagic Escherichia coli (EHEC

Directory of Open Access Journals (Sweden)

Abdullah Kilic

2011-08-01

Full Text Available Escherichia coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless for human. E. coli O157:H7 is the most common member of a group of pathogenic E. coli strains known variously as enterohaemorrhagic, verocytotoxin-producing, or Shiga-toxin-producing organisms. EHEC bacterium is the major cause of haemorrhagic colitis and haemolytic uraemic syndrome. The reservoir of this pathogen appears to be mainly cattle and other ruminants such as camels. It is transmitted to humans primarily through consumption of contaminated foods. [TAF Prev Med Bull 2011; 10(4.000: 387-388

Fed-batch methanol feeding strategy for recombinant protein production by Pichia pastoris in the presence of co-substrate sorbitol.

Science.gov (United States)

Celik, Eda; Calik, Pinar; Oliver, Stephen G

2009-09-01

Batch-wise sorbitol addition as a co-substrate at the induction phase of methanol fed-batch fermentation by Pichia pastoris (Mut(+)) was proposed as a beneficial recombinant protein production strategy and the metabolic responses to methanol feeding rate in the presence of sorbitol was systematically investigated. Adding sorbitol batch-wise to the medium provided the following advantages over growth on methanol alone: (a) eliminating the long lag-phase for the cells and reaching 'high cell density production' at t = 24 h of the process (C(X) = 70 g CDW/l); (b) achieving 1.8-fold higher recombinant human erythropoietin (rHuEPO) (at t = 18 h); (c) reducing specific protease production 1.2-fold; (d) eliminating the lactic acid build-up period; (e) lowering the oxygen uptake rate two-fold; and (f) obtaining 1.4-fold higher overall yield coefficients. The maximum specific alcohol oxidase activity was not affected in the presence of sorbitol, and it was observed that sorbitol and methanol were utilized simultaneously. Thus, in the presence of sorbitol, 130 mg/l rHuEPO was produced at t = 24 h, compared to 80 mg/l rHuEPO (t = 24 h) on methanol alone. This work demonstrates not only the ease and efficiency of incorporating sorbitol to fermentations by Mut(+) strains of P. pastoris for the production of any bio-product, but also provides new insights into the metabolism of the methylotrophic yeast P. pastoris.

[Construction of enterohemorrhagic Escherichia coli O157:H7 strains with espF gene deletion and complementation].

Science.gov (United States)

Hua, Ying; Sun, Qi; Wang, Xiangyu; DU, Yanli; Shao, Na; Zhang, Qiwei; Zhao, Wei; Wan, Chengsong

2015-11-01

To construct enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains with delection espF gene and its nucleotide fragment and with espF gene complementation. A pair of homologous arm primers was designed to amplify the gene fragment of kanamycin resistance, which was transformed into EHEC O157:H7 EDL933w strain via the PKD46 plasmid by electroporation. The replacement of the espF gene by kanamycin resistance gene through the PKD46-mediated red recombination system was confirmed by PCR and sequencing. The entire coding region of espF along with its nucleotide fragment was amplified by PCR and cloned into pBAD33 plasmid, which was transformed into a mutant strain to construct the strain with espF complementation. RT-PCR was used to verify the transcription of espF and its nucleotide fragment in the complemented mutant strain. We established EHEC O157:H7 EDL933w strains with espF gene deletion and with espF gene complementation. Both espF and its nucleotide fragment were transcribed in the complemented mutant strain. The two strains provide a basis for further study of the regulatory mechanism of espF.

Viability of L. casei during fermentation in soymilk and freeze-dried soymilk; effect of cryoprotectant, rehydration and storage temperature

Directory of Open Access Journals (Sweden)

Kristina Mladenovska

2005-12-01

Full Text Available The aim of the work was to investigate the behaviour of L. casei and the effect of sorbitol on its viability during fermentation in soymilk drink. Values for pH, ranging from 6.82 to 3.42 in the soymilk drink without sorbitol and from 6.74 to 3.41 in the drink with sorbitol were noted during 72 h of fermentation at 25oC. The corresponding values for titratable acidity ranged from 0.071% to 0.758% and from 0.073% to 0.761%, respectively. Soymilk was found to support the growth of L. casei with improvement in viability for 0.24 log at the end of fermentation when sorbitol was added. Survival of L. casei and the effectiveness of sorbitol in improving viability during freeze-drying, subsequent rehydration and during a 5-week period of storage under different temperatures were also investigated. After freeze-drying, L. casei exhibited a survival percent of approximately 46%. Sorbitol improved the viability of L. casei by 0.51 log immediately after freeze-drying and by 1.30 log and 0.47 log during five weeks of storage at 25oC and 4oC, respectively. Further study revealed that the freeze-dried fermented soymilk rehydrated at 45oC was optimum for the recovery of L. casei with improvement in recovery for 0.68 log when sorbitol was added. A higher percent of survival was noted when the dried soymilk was stored at 4oC than at 25oC with improved viability at the end of 5 weeks storage for approximately 6 log for drinks with and without sorbitol. Fermented dried soymilk with sorbitol afforded significant tolerance of L. casei to acid stress. Generally, a stable probiotic diary product was prepared in which the concentration of L. casei remained above therapeutic level of 107 cfu/ml.

Modified Vero cell induced by Bifidobacterium bifidum inhibits enterohemorrhagic Escherichia coli O157:H7 cytopathic effect

Directory of Open Access Journals (Sweden)

Tahamtan, Y.

2014-11-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC, such as E. coli O157:H7, are emerging food-borne pathogens worldwide. This micro-organism can damage the epithelial tissue of the large intestine. The cytotoxic effects can be neutralized by probiotics such as Bifidobacterium bifidum. Probiotics are viable cells that have beneficial effects on the health of the host. The preventing activity of B. bifidum against E. coli O157 was studied using a Vero cell model. Vero cell was pretreated with viable B. bifidum and incubated for either 3 h to 24 h and then collected from the cell to make modified Vero cell (MVC. Indirect antibacterial effects of B. bifidum were demonstrated by reduction of attachment of E. coli O157:H7 to MVC. The maximum reduction was resulted in pretreatment of Vero cell with B. bifidum for 24 h before infection. B. bifidum attenuated E. coli O157:H7 attachment to MVC up to 10 days of incubation. To our knowledge, MCV prevented Vero cell line injury induced by E. coli O157:H7. Therefore, B. bifidum can be used for inhibition of E. coli O157:H7 cytopathic effect (CPE in Vero cell model, even as pretreatment of the cell line.

Fermented soya bean (tempe) extracts reduce adhesion of enterotoxigenic Escherichia coli to intestinal epithelial cells

NARCIS (Netherlands)

Roubos-van den Hil, P.J.; Nout, M.J.R.; Beumer, R.R.; Meulen, van der J.; Zwietering, M.H.

2009-01-01

Aims: This study aimed to investigate the effect of processed soya bean, during the successive stages of tempe fermentation and different fermentation times, on adhesion of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal brush border cells as well as Caco-2 intestinal epithelial cells; and

Milk Fat Globules Hamper Adhesion of Enterohemorrhagic Escherichia coli to Enterocytes: In Vitro and in Vivo Evidence

Directory of Open Access Journals (Sweden)

Thomas Douëllou

2018-05-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC; E. coli are food-borne agents associated with gastroenteritis, enterocolitis, bloody diarrhea and the hemolytic-uremic syndrome (HUS. Bovine milk glycans have been shown to contain oligosaccharides which are similar to host epithelial cell receptors and can therefore prevent bacterial adhesion. This study aimed to describe interactions between EHEC O157:H7 EDL933 and O26:H11 21765 and milk fat globules (MFGs in raw milk and raw milk cheese, and the impact of MFGs on EHEC strains adhesion to the intestinal tract in vitro and in vivo. Both EHEC serotypes clearly associated with native bovine MFGs and significantly limited their adhesion to a co-culture of intestinal cells. The presence of MFGs in raw milk cheese had two effects on the adhesion of both EHEC serotypes to the intestinal tracts of streptomycin-treated mice. First, it delayed and reduced EHEC excretion in mouse feces for both strains. Second, the prime implantation site for both EHEC strains was 6 cm more proximal in the intestinal tracts of mice fed with contaminated cheese containing less than 5% of fat than in those fed with contaminated cheese containing 40% of fat. Feeding mice with 40% fat cheese reduced the intestinal surface contaminated with EHEC and may therefore decrease severity of illness.

Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food and In Vitro.

Science.gov (United States)

Böhnlein, Christina; Kabisch, Jan; Meske, Diana; Franz, Charles M A P; Pichner, Rohtraud

2016-11-01

In 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rare Escherichia coli serotype, O104:H4, that shared the virulence profiles of Shiga toxin-producing E. coli (STEC)/enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food or in vitro, were compared with those of E. coli O157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable than E. coli O157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward several E. coli strains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead of E. coli O157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential. In 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive

The effects of potassium and chloride ions on the ethanolic fermentation of sucrose by Zymomonas mobilis 2716

Energy Technology Data Exchange (ETDEWEB)

Kirk, L A; Doelle, H W [Queensland Univ., Brisbane (Australia). Dept. of Microbiology

1992-04-01

The inclusion of specific salts in Zymomonas mobilis batch sucrose fermentations can limit by-product formation. Sorbitol and fructo-oligosaccharide formation can be reduced and ethanol production enhanced by manipulating mineral salt concentrations. Chloride salts reduced the production of biomass and sorbitol in favour of fructo-obligosaccharide formation at concentrations lower than 10 g NaCl/l or MgCl{sub 2}. Higher concentrations led to the accumulation of glucose and fructose. Low concentrations of KH{sub 2}PO{sub 4} (<20 g/l) enhanced biomass formation, and the concomitant reduction in sorbitol and fructo-obligosaccharides favoured enhanced ethanol formation. At concentrations above 20 g/l, its effects were similar to those obtained with the chloride salts. Invertase addition at the start of fermentation increased sorbitol formation, whereas addition after the completion of sucrose hydrolysis resulted in the conversion of fructo-obligosaccharides formed into fructose or ethanol. Fermentation with 250 g/l of sugar-cane syrup (=130 g sucrose/l) in the presence of 8 g KH{sub 2}PO{sub 4}/l, with 0.05 g invertase/l added on the completion of sucrose hydrolysis, resulted in a conversion efficiency of 94% with complete carbon accountability, and only 7 g sorbitol/l. (orig.).

Enhanced production of L-sorbose from D-sorbitol by improving the mRNA abundance of sorbitol dehydrogenase in Gluconobacter oxydans WSH-003.

Science.gov (United States)

Xu, Sha; Wang, Xiaobei; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2014-10-18

Production of L-sorbose from D-sorbitol by Gluconobacter oxydans is the first step to produce L-ascorbic acid on industrial scale. The sldhAB gene, which encodes the sorbitol dehydrogenase (SLDH), was overexpressed in an industrial strain G. oxydans WSH-003 with a strong promoter, P tufB . To enhance the mRNA abundance, a series of artificial poly(A/T) tails were added to the 3'-terminal of sldhAB gene. Besides, their role in sldhAB overexpression and their subsequent effects on L-sorbose production were investigated. The mRNA abundance of the sldhAB gene could be enhanced in G. oxydans by suitable poly(A/T) tails. By self-overexpressing the sldhAB gene in G. oxydans WSH-003 with an optimal poly(A/T) tail under the constitutive promoter P tufB , the titer and the productivity of L-sorbose were enhanced by 36.3% and 25.0%, respectively, in a 1-L fermenter. Immobilization of G. oxydans-sldhAB6 cells further improved the L-sorbose titer by 33.7% after 20 days of semi-continuous fed-batch fermentation. The artificial poly(A/T) tails could significantly enhance the mRNA abundance of the sldhAB. Immobilized G. oxydans-sldhAB6 cells could further enlarge the positive effect caused by enhanced mRNA abundance of the sldhAB.

Sorbitol Can Fuel Mouse Sperm Motility and Protein Tyrosine Phosphorylation via Sorbitol Dehydrogenase1

Science.gov (United States)

Cao, Wenlei; Aghajanian, Haig K.; Haig-Ladewig, Lisa A.; Gerton, George L.

2008-01-01

Energy sources that can be metabolized to yield ATP are essential for normal sperm functions such as motility. Two major monosaccharides, sorbitol and fructose, are present in semen. Furthermore, sorbitol dehydrogenase (SORD) can convert sorbitol to fructose, which can then be metabolized via the glycolytic pathway in sperm to make ATP. Here we characterize Sord mRNA and SORD expression during mouse spermatogenesis and examine the ability of sorbitol to support epididymal sperm motility and tyrosine phosphorylation. Sord mRNA levels increased during the course of spermatogenic differentiation. SORD protein, however, was first detected at the condensing spermatid stage. By indirect immunofluorescence, SORD was present along the length of the flagella of caudal epididymal sperm. Furthermore, immunoelectron microscopy showed that SORD was associated with mitochondria and the plasma membranes of sperm. Sperm incubated with sorbitol maintained motility, indicating that sorbitol was utilized as an energy source. Sorbitol, as well as glucose and fructose, were not essential to induce hyperactive motility. Protein tyrosine phosphorylation increased in a similar manner when sorbitol was substituted for glucose in the incubation medium used for sperm capacitation. These results indicate that sorbitol can serve as an alternative energy source for sperm motility and protein tyrosine phosphorylation. PMID:18799757

Metabolic engineering of Escherichia coli to enhance shikimic acid production from sorbitol.

Science.gov (United States)

Liu, Xianglei; Lin, Jun; Hu, Haifeng; Zhou, Bin; Zhu, Baoquan

2014-09-01

Shikimic acid (SA) is the key synthetic material of Oseltamivir, which is an effective drug for the prevention and treatment of influenza. In this study, to block the downstream metabolic pathway of SA, the shikimate kinase isoenzyme genes aroK and aroL were deleted by Red recombination. Moreover, the key enzyme genes aroG, aroB, tktA and aroE of SA pathway were co-expressed by constructing the recombinant vector pETDuet-GBAE. As a result, SA production of E. coli BW25113 (∆aroL/aroK, DE3)/pETDuet-GBAE reached 1,077.6 mg/l when low amounts of sorbitol (5 g/l) were fed in shake flasks. The yield was 3.7 times that when glucose was used (P sorbitol was an optimized carbon source for the high efficient accumulation of SA for the first time, which was applicable to use in the industry for high yields and low consumption.

21 CFR 184.1835 - Sorbitol.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sorbitol. 184.1835 Section 184.1835 Food and Drugs... Substances Affirmed as GRAS § 184.1835 Sorbitol. (a) Sorbitol is the chemical 1,2,3,4,5,6-hexanehexol.... Sorbitol is produced by the electrolytic reduction, or the transition metal catalytic hydrogenation of...

Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

Science.gov (United States)

Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even

2011-11-01

After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages. Copyright © 2011 Elsevier Ltd. All rights reserved.

Lipase-Catalyzed Production of 6-O-cinnamoyl-sorbitol from D-sorbitol and Cinnamic Acid Esters.

Science.gov (United States)

Kim, Jung-Ho; Bhatia, Shashi Kant; Yoo, Dongwon; Seo, Hyung Min; Yi, Da-Hye; Kim, Hyun Joong; Lee, Ju Hee; Choi, Kwon-Young; Kim, Kwang Jin; Lee, Yoo Kyung; Yang, Yung-Hun

2015-05-01

To overcome the poor properties of solubility and stability of cinnamic acid, cinnamate derivatives with sugar alcohols were produced using the immobilized Candida antarctica lipase with vinyl cinnamate and D-sorbitol as substrate at 45 °C. Immobilized C. antarctica lipase was found to synthesize 6-O-cinnamoyl-sorbitol and confirmed by HPLC and (1)H-NMR and had a preference for vinyl cinnamate over other esters such as allyl-, ethyl-, and isobutyl cinnamate as co-substrate with D-sorbitol. Contrary to D-sorbitol, vinyl cinnamate, and cinnamic acid, the final product 6-O-cinnamoyl-sorbitol was found to have radical scavenging activity. This would be the first report on the biosynthesis of 6-O-cinnamoyl-sorbitol with immobilized enzyme from C. antarctica.

Sorbitol Can Fuel Mouse Sperm Motility and Protein Tyrosine Phosphorylation via Sorbitol Dehydrogenase1

OpenAIRE

Cao, Wenlei; Aghajanian, Haig K.; Haig-Ladewig, Lisa A.; Gerton, George L.

2009-01-01

Energy sources that can be metabolized to yield ATP are essential for normal sperm functions such as motility. Two major monosaccharides, sorbitol and fructose, are present in semen. Furthermore, sorbitol dehydrogenase (SORD) can convert sorbitol to fructose, which can then be metabolized via the glycolytic pathway in sperm to make ATP. Here we characterize Sord mRNA and SORD expression during mouse spermatogenesis and examine the ability of sorbitol to support epididymal sperm motility and t...

Viability of L. casei during fermentation in soymilk and freeze-dried soymilk; effect of cryoprotectant, rehydration and storage temperature

OpenAIRE

Kristina Mladenovska; Tanja Petreska Ivanovska; Maja Jurhar Pavlova; Milena Petrovska; Angela Delova; Lidija Petrusevska Tozi; Lela Acevska

2005-01-01

The aim of the work was to investigate the behaviour of L. casei and the effect of sorbitol on its viability during fermentation in soymilk drink. Values for pH, ranging from 6.82 to 3.42 in the soymilk drink without sorbitol and from 6.74 to 3.41 in the drink with sorbitol were noted during 72 h of fermentation at 25oC. The corresponding values for titratable acidity ranged from 0.071% to 0.758% and from 0.073% to 0.761%, respectively. Soymilk was found to support the growth of L. case...

THE WIDESPREAD OCCURRENCE OF THE ENTEROHEMOLYSIN GENE EHLYA AMONG ENVIRONMENTAL STRAINS OF ESCHERICHIA COLI

Science.gov (United States)

The putative virulence factor enterohemolysin, encoded for by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. E. coli isolates from effluents from seven geographically dispersed municipal ...

Cellulase and Xylanase Production by Penicillium echinulatum in Submerged Media Containing Cellulose Amended with Sorbitol

Directory of Open Access Journals (Sweden)

Carla Eliana Todero Ritter

2013-01-01

Full Text Available The present work investigated the use of sorbitol as a soluble carbon source, in association with cellulose, to produce cellulases and xylanases in submerged cultures of Penicillium echinulatum 9A02S1. Because cellulose is an insoluble carbon source, in cellulase production, there are some problems with rheology and oxygen transfer. The submerged fermentations containing media composed of 0, 0.25, 0.5, 0.75, and 1% (w/v sorbitol and cellulose that were added at different times during the cultivation; 0.2% (w/v soy bran; 0.1% (w/v wheat bran; and a solution of salts. The highest filter paper activity (FPA ( IU·mL−1 was obtained on the seventh day in the medium containing 0.5% (w/v sorbitol and 0.5% (w/v cellulose added 24 h after the start of cultivation. However, the CMCases showed an activity peak on the sixth day ( IU·mL−1 in the medium containing 0.75% (w/v sorbitol and 0.75% (w/v cellulose added after 12 h of cultivation. The xylanases showed the highest activity in the medium with 0.75% (w/v sorbitol and 0.25% (w/v cellulose added 36 h after the start of cultivation. This strategy enables the reduction of the cellulose concentration, which in high concentrations can cause rheological and oxygen transfer problems.

Overexpression, purification and crystallization of the tetrameric form of SorC sorbitol operon regulator

International Nuclear Information System (INIS)

Sanctis, Daniele de; Rêgo, Ana T.; Marçal, David; McVey, Colin E.; Carrondo, Maria A.; Enguita, Francisco J.

2007-01-01

The sorbitol operon regulator from K. pneumoniae has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 3.2 Å. The sorbitol operon regulator (SorC) regulates the metabolism of l-sorbose in Klebsiella pneumonia. SorC was overexpressed in Escherichia coli and purified, and crystals were obtained of a tetrameric form. A single crystal showed X-ray diffraction to 3.20 Å. The crystal belongs to space group P2 1 2 1 2 1 , with unit-cell parameters a = 91.6, b = 113.3, c = 184.1 Å. Analysis of the molecular-replacement solution indicates the presence of four SorC molecules in the asymmetric unit

A highly efficient sorbitol dehydrogenase from Gluconobacter oxydans G624 and improvement of its stability through immobilization.

Science.gov (United States)

Kim, Tae-Su; Patel, Sanjay K S; Selvaraj, Chandrabose; Jung, Woo-Suk; Pan, Cheol-Ho; Kang, Yun Chan; Lee, Jung-Kul

2016-09-16

A sorbitol dehydrogenase (GoSLDH) from Gluconobacter oxydans G624 (G. oxydans G624) was expressed in Escherichia coli BL21(DE3)-CodonPlus RIL. The complete 1455-bp codon-optimized gene was amplified, expressed, and thoroughly characterized for the first time. GoSLDH exhibited Km and kcat values of 38.9 mM and 3820 s(-1) toward L-sorbitol, respectively. The enzyme exhibited high preference for NADP(+) (vs. only 2.5% relative activity with NAD(+)). GoSLDH sequencing, structure analyses, and biochemical studies, suggested that it belongs to the NADP(+)-dependent polyol-specific long-chain sorbitol dehydrogenase family. GoSLDH is the first fully characterized SLDH to date, and it is distinguished from other L-sorbose-producing enzymes by its high activity and substrate specificity. Isothermal titration calorimetry showed that the protein binds more strongly to D-sorbitol than other L-sorbose-producing enzymes, and substrate docking analysis confirmed a higher turnover rate. The high oxidation potential of GoSLDH for D-sorbitol was confirmed by cyclovoltametric analysis. Further, stability of GoSLDH significantly improved (up to 13.6-fold) after cross-linking of immobilized enzyme on silica nanoparticles and retained 62.8% residual activity after 10 cycles of reuse. Therefore, immobilized GoSLDH may be useful for L-sorbose production from D-sorbitol.

21 CFR 582.5835 - Sorbitol.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sorbitol. 582.5835 Section 582.5835 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... § 582.5835 Sorbitol. (a) Product. Sorbitol. (b) Conditions of use. This substance is generally...

prevalence of escherichia coli 0157:h7 in fresh and roasted beef

African Journals Online (AJOL)

DR. AMINU

The prevalence of Enterohemorrhagic Escherichia coli 0157:H7 in 300 fresh beef and 150 roasted beef samples from ... likely cause of E. coli O157:H7 infection is undercooked ground beef. ..... coli O157:H7 in a sheep model. Appl. Environ.

Dark fermentative hydrogen and ethanol production from biodiesel waste glycerol using a co-culture of Escherichia coli and Enterobacter sp.

NARCIS (Netherlands)

Maru, B.T.; López, F.; Kengen, S.W.M.; Constantí, M.; Medina, F.

2016-01-01

In previous comparative studies, Enterobacter spH1 was selected as the best hydrogen and ethanol producer (Knothe, 2010). Here, glycerol fermentation was compared between three other strains: Escherichia coli CECT432, Escherichia coli CECT434 and Enterobacter cloacae MCM2/1. E. coli CECT432 was

Lysogeny with Shiga Toxin 2-Encoding Bacteriophages Represses Type III Secretion in Enterohemorrhagic Escherichia coli

Science.gov (United States)

Xu, Xuefang; McAteer, Sean P.; Tree, Jai J.; Shaw, Darren J.; Wolfson, Eliza B. K.; Beatson, Scott A.; Roe, Andrew J.; Allison, Lesley J.; Chase-Topping, Margo E.; Mahajan, Arvind; Tozzoli, Rosangela; Woolhouse, Mark E. J.; Morabito, Stefano; Gally, David L.

2012-01-01

Lytic or lysogenic infections by bacteriophages drive the evolution of enteric bacteria. Enterohemorrhagic Escherichia coli (EHEC) have recently emerged as a significant zoonotic infection of humans with the main serotypes carried by ruminants. Typical EHEC strains are defined by the expression of a type III secretion (T3S) system, the production of Shiga toxins (Stx) and association with specific clinical symptoms. The genes for Stx are present on lambdoid bacteriophages integrated into the E. coli genome. Phage type (PT) 21/28 is the most prevalent strain type linked with human EHEC infections in the United Kingdom and is more likely to be associated with cattle shedding high levels of the organism than PT32 strains. In this study we have demonstrated that the majority (90%) of PT 21/28 strains contain both Stx2 and Stx2c phages, irrespective of source. This is in contrast to PT 32 strains for which only a minority of strains contain both Stx2 and 2c phages (28%). PT21/28 strains had a lower median level of T3S compared to PT32 strains and so the relationship between Stx phage lysogeny and T3S was investigated. Deletion of Stx2 phages from EHEC strains increased the level of T3S whereas lysogeny decreased T3S. This regulation was confirmed in an E. coli K12 background transduced with a marked Stx2 phage followed by measurement of a T3S reporter controlled by induced levels of the LEE-encoded regulator (Ler). The presence of an integrated Stx2 phage was shown to repress Ler induction of LEE1 and this regulation involved the CII phage regulator. This repression could be relieved by ectopic expression of a cognate CI regulator. A model is proposed in which Stx2-encoding bacteriophages regulate T3S to co-ordinate epithelial cell colonisation that is promoted by Stx and secreted effector proteins. PMID:22615557

Fatores de virulência em linhagens de Escherichia coli isoladas de mastite bovina Virulence factors in Escherichia coli strains isolated from bovine mastitis

Directory of Open Access Journals (Sweden)

M.G. Ribeiro

2006-10-01

Full Text Available Avaliou-se a ocorrência de fatores de virulência e do sorotipo O157:H7 em 120 linhagens de Escherichia coli, isoladas de 80 casos de mastite clínica bovina e 40 de mastite subclínica. Verificou-se alfa-hemolisina em oito (6,7% linhagens, isoladas de cinco casos de mastite clínica e três de mastite subclínica e em nenhuma das estirpes detectou-se enteroemolisina. A presença de sideróforos foi encontrada em 11 (9,2% linhagens, sete de mastite clínica e quatro de subclínica. Em duas (1,7% estirpes isoladas de mastite subclínica, identificou-se enterotoxina STa. Observou-se efeito citopático em células vero compatível com a produção de verotoxina-VT em cinco (4,2% linhagens, duas de mastite clínica e três subclínicas. Em uma (0,8% linhagem isolada de mastite clínica, detectou-se efeito citopático compatível com o fator necrosante citotóxico. Nenhuma estirpe apresentou-se sorbitol-negativa no MacConkey-sorbitol, tampouco aglutinou com o sorotipo O157:H7. Os antimicrobianos mais efetivos foram polimixina B (97,5% e norfloxacina (95,8%. Observou-se multi-resistência a dois ou mais antimicrobianos em 24 (20% estirpes, principalmente com o uso de ampicilina e ceftiofur.The occurrence of different virulence factors and O157:H7 serotype investigation in 120 Escherichia coli strains isolated from clinical (80 cases and subclinical (40 cases bovine mastitis was evaluated. Alpha-haemolysin was detected in 8 (6.7% strains (5 clinical and 3 subclinical cases. None strain showed enterohaemolysin production. E. coli growth under iron restriction conditions (siderophores production was observed in 11 (9.2% strains (7 clinical and 4 subclinical cases. STa enterotoxin was detected in 2 (1.7% strains from subclinical cases. Cytotoxic effect in vero cells compatible with verotoxin-VT production was observed in 5 (4.2% strains (2 clinical and 3 subclinical cases. One strain (0.8% isolated from clinical mastitis showed cytophatic effect in vero

Escherichia coli enterohemorrágica y síndrome urémico hemolítico en Argentina Enterohemorrhagic Escherichia coli and hemolytic-uremic syndrome in Argentina

Directory of Open Access Journals (Sweden)

Mariana A. Rivero

2004-08-01

Full Text Available El síndrome urémico hemolítico (SUH.es un desorden multisistémico caracterizado por presentar insuficiencia renal aguda, anemia hemolítica microangiopática y trombocitopenia. Constituye la principal causa de insuficiencia renal aguda y la segunda causa de insuficiencia renal crónica y de transplante renal en niños en la Argentina. Actualmente, nuestro país presenta el registro más alto de SUH en todo el mundo, con aproximadamente 420 casos nuevos declarados anualmente y una incidencia de 12.2/100 000 niños menores de 5 años de edad. Se reconocen múltiples agentes etiológicos, aunque se considera a la infección por Escherichia coli enterohemorrágica (EHEC como la principal etiología de SUH. La gran mayoría de brotes epidémicos y casos esporádicos en humanos se han asociado con el serotipo O157:H7, aunque otros serotipos han sido también aislados, y éstos son un subgrupo de E. coli verocitotoxigénico (VTEC..El bovino es considerado el principal reservorio de VTEC. El contagio al hombre frecuentemente se debe al consumo de alimentos cárneos y lácteos contaminados, deficientemente cocidos o sin pasteurizar, o al contacto directo con los animales o con sus heces, consumo de agua, frutas o verduras contaminadas. También puede producirse contagio mediante el contacto interhumano.The hemolytic-uremic syndrome (HUS is a multisystemic disorder that is characterized by the onset of acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. It is the most common cause of acute renal failure and the second cause of chronic renal failure and renal transplantation in children in Argentina. Our country has the highest incidence of HUS in the world, with approximately 420 new cases observed each year with an incidence of 12.2 cases per 100 000 children in the age group 0-5 years. Numerous etiologic factors have been associated with HUS but the infection with enterohemorrhagic Escherichia coli (EHEC is considered the

Metabolic engineering of Escherichia coli for production of mixed-acid fermentation end products

Directory of Open Access Journals (Sweden)

Andreas Hartmut Förster

2014-05-01

Full Text Available Mixed-acid fermentation end products have numerous applications in biotechnology. This is probably the main driving force for the development of multiple strains that are supposed to produce individual end products with high yields. The process of engineering Escherichia coli strains for applied production of ethanol, lactate, succinate, or acetate was initiated several decades ago and is still ongoing. This review follows the path of strain development from the general characteristics of aerobic versus anaerobic metabolism over the regulatory machinery that enables the different metabolic routes. Thereafter, major improvements for broadening the substrate spectrum of Escherichia coli towards cheap carbon sources like molasses or lignocellulose are highlighted before major routes of strain development for the production of ethanol, acetate, lactate and succinate are presented.

The interacting Cra and KdpE regulators are involved in the expression of multiple virulence factors in enterohemorrhagic Escherichia coli.

Science.gov (United States)

Njoroge, Jacqueline W; Gruber, Charley; Sperandio, Vanessa

2013-06-01

The human pathogen enterohemorrhagic Escherichia coli (EHEC) O157:H7 codes for two interacting DNA binding proteins, Cra and KdpE, that coregulate expression of the locus of enterocyte effacement (LEE) genes in a metabolite-dependent manner. Cra is a transcription factor that uses fluctuations in the concentration of carbon metabolism intermediates to positively regulate virulence of EHEC. KdpE is a response regulator that activates the transcription of homeostasis genes in response to salt-induced osmolarity and virulence genes in response to changes in metabolite concentrations. Here, we probed the transcriptional profiles of the Δcra, ΔkdpE, and Δcra ΔkdpE mutant strains and show that Cra and KdpE share several targets besides the LEE, but both Cra and KdpE also have independent targets. Several genes within O-islands (genomic islands present in EHEC but absent from E. coli K-12), such as Z0639, Z0640, Z3388, Z4267, and espFu (encoding an effector necessary for formation of attaching and effacing lesions on epithelial cells), were directly regulated by both Cra and KdpE, while Z2077 was only regulated by Cra. These studies identified and confirmed new direct targets for Cra and KdpE that included putative virulence factors as well as characterized virulence factors, such as EspFu and EspG. These results map out the role of the two interacting regulators, Cra and KdpE, in EHEC pathogenesis and global gene regulation.

21 CFR 862.1670 - Sorbitol dehydrogenase test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Sorbitol dehydrogenase test system. 862.1670... Systems § 862.1670 Sorbitol dehydrogenase test system. (a) Identification. A sorbitol dehydrogenase test system is a device intended to measure the activity of the enzyme sorbitol dehydrogenase in serum...

Effect of RNase E deficiency on translocon protein synthesis in an RNase E-inducible strain of enterohemorrhagic Escherichia coli O157:H7.

Science.gov (United States)

Lodato, Patricia B; Thuraisamy, Thujitha; Richards, Jamie; Belasco, Joel G

2017-07-06

Enterohemorrhagic Escherichia coli (EHEC) is a food-borne pathogen that assembles a type III secretion system (T3SS) on its surface. The last portion of the T3SS, called the 'translocon', is composed of a filament and a pore complex that is inserted into the membrane of intestinal epithelial cells. The genes encoding the translocon (espADB) are part of the LEE4 operon. Their expression is regulated by a complex post-transcriptional mechanism that involves the processing of LEE4 mRNA by the essential endoribonuclease RNase E. Here, we report the construction of an EHEC strain (TEA028-rne) in which RNase E can be induced by adding IPTG to the culture medium. EHEC cells deficient in RNase E displayed an abnormal morphology and slower growth, in agreement with published observations in E. coli K-12. Under those conditions, EspA and EspB were produced at higher concentrations, and protein secretion still occurred. These results indicate that RNase E negatively regulates translocon protein synthesis and demonstrate the utility of E. coli strain TEA028-rne as a tool for investigating the influence of this ribonuclease on EHEC gene expression in vitro. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

75 FR 39277 - Sorbitol From France; Determination

Science.gov (United States)

2010-07-08

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-44 (Third Review)] Sorbitol From France... U.S.C. 1675d(c)) (the Act), that revocation of the antidumping duty order on sorbitol from France... views of the Commission are contained in USITC Publication 4164 (June 2010), entitled Sorbitol from...

Survival of pathogenic enterohemorrhagic Escherichia coli (EHEC) and control with calcium oxide in frozen meat products.

Science.gov (United States)

Ro, Eun Young; Ko, Young Mi; Yoon, Ki Sun

2015-08-01

This study investigated both the level of microbial contamination and the presence of enterohemorrhagic Escherichia coli (EHEC) in frozen meat products, followed by the evaluation of its survival over 180 days under frozen temperature. We also examined the effect of calcium oxide on the populations of EHEC, E. coli O157:H7 and EPEC under both 10 °C and -18 °C storage conditions. Afterward, the morphological changes occurring in EHEC cells in response to freezer storage temperature and calcium oxide (CaO) treatments were examined using transmission electron microscopy. Among the frozen meat products tested, the highest contamination levels of total aerobic counts, coliforms and E. coli were observed in pork cutlets. Examination showed that 20% of the frozen meat products contained virulence genes, including verotoxin (VT) 1 and 2. Over 180 days of frozen storage and after 3 freeze-thaw cycles, the population of EHEC did not change regardless of the type of products or initial inoculated concentration, indicating the strong survival ability of EHEC. Subsequent testing revealed that the growth of three pathogenic E. coli strains was completely inhibited in meat patties prepared with 1% CaO, stored at 10 °C. However, the addition of 2% CaO was necessary to control the survival of EHEC, E. coli O157:H7 and EPEC in meat patties stored at -18 °C. CaO reduced the population of E. coli O157:H7 more effectively than the other EHEC and EPEC strains at both 10 °C and -18 °C. Transmission electron microscopy analysis revealed that exposed EHEC cells were resistant to the freezer storage temperature, although some cells incurred injury and death after several freeze-thaw cycles. Most of the cells exposed to CaO were found to have died or lost their cellular integrity and membranes, indicating that CaO has the potential to be used as a powerful antimicrobial agent for manufacturing frozen meat products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of UV-C and Pulsed UV Light Treatments for Reduction of Salmonella, Listeria monocytogenes, and Enterohemorrhagic Escherichia coli on Eggs.

Science.gov (United States)

Holck, Askild L; Liland, Kristian H; Drømtorp, Signe M; Carlehög, Mats; McLEOD, Anette

2018-01-01

Ten percent of all strong-evidence foodborne outbreaks in the European Union are caused by Salmonella related to eggs and egg products. UV light may be used to decontaminate egg surfaces and reduce the risk of human salmonellosis infections. The efficiency of continuous UV-C (254 nm) and pulsed UV light for reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, and enterohemorrhagic Escherichia coli on eggs was thoroughly compared. Bacterial cells were exposed to UV-C light at fluences from 0.05 to 3.0 J/cm 2 (10 mW/cm 2 , for 5 to 300 s) and pulsed UV light at fluences from 1.25 to 18.0 J/cm 2 , resulting in reductions ranging from 1.6 to 3.8 log, depending on conditions used. Using UV-C light, it was possible to achieve higher reductions at lower fluences compared with pulsed UV light. When Salmonella was stacked on a small area or shielded in feces, the pulsed UV light seemed to have a higher penetration capacity and gave higher bacterial reductions. Microscopy imaging and attempts to contaminate the interior of the eggs with Salmonella through the eggshell demonstrated that the integrity of the eggshell was maintained after UV light treatments. Only minor sensory changes were reported by panelists when the highest UV doses were used. UV-C and pulsed UV light treatments appear to be useful decontamination technologies that can be implemented in continuous processing.

Does enterohemorrhagic Escherichia coli O157:H7 enter the viable but nonculturable state in salted salmon roe?

Science.gov (United States)

Makino, S I; Kii, T; Asakura, H; Shirahata, T; Ikeda, T; Takeshi, K; Itoh, K

2000-12-01

An outbreak caused by salted salmon roe contaminated with enterohemorrhagic Escherichia coli O157 occurred in Japan in 1998. Since about 0.75 to 1.5 viable cells were estimated to cause infection, we presumed that O157 might enter the viable but nonculturable (VNC) state in salted salmon roe and consequently that viable cell numbers might be underestimated. Although patient-originating O157 cells could not grow on agar plates after 72 h of incubation in 13% NaCl, they were resuscitated in yeast extract broth, and more than 90% of the cells were shown to be viable by fluorescent staining, suggesting that almost all of them could enter the VNC state in NaCl water. Roe-originating O157 was resistant to NaCl because it could grow on agar after 72 h of incubation in NaCl water, but about 20% of cells appeared to enter the VNC state. Therefore, germfree mice were infected with O157 to examine the resuscitation of cells in the VNC state and the retention of pathogenicity. O157 that originated in roe, but not patients, killed mice and was isolated from the intestine. However, these isolates had become sensitive to NaCl. O157 cells of roe origin incubated in normal media also killed mice and were isolated from the intestine, but they also became transiently NaCl sensitive. We therefore propose that bacterial cells might enter the VNC state under conditions of stress, such as those encountered in vivo or in high salt concentrations, and then revive when those conditions have eased. If so, the VNC state in food is potentially dangerous from a public health viewpoint and may have to be considered at the time of food inspection. Finally, the establishment of a simple recovery system for VNC cells should be established.

The metabolic fate of exogenous sorbitol in the rat

International Nuclear Information System (INIS)

Ertel, N.H.; Akgun, S.; Kemp, F.W.; Mittler, J.C.

1983-01-01

Dietary sorbitol is rapidly converted to fructose and other carbohydrates in the liver, but its metabolic fate has not been studied rigorously. Twenty-four rats were given 20.4 muCi [ 14 C]sorbitol with 100 mg of sorbitol, and groups of six were killed at 1, 3, 6, and 24 hours after sorbitol administration. Rats were also fed 6.9 muCi [ 14 C]sorbitol for 7 or 14 days. Serum, liver, and lens were analyzed for 14 C-labeled sorbitol, fructose, and glucose by using high-performance liquid chromatography. Negligible radioactivity (1.1%) was found in the gastrointestinal content at 24 hours indicating virtually complete absorption. Most of the radioactivity was recovered in the glucose fraction in serum, liver and lens. Glucose and fructose concentrations showed some decline by day 14 compared with day 7 in serum and liver. However, in the lens, sorbitol showed a peak value at the end of the 14th day (37.5 +/- 9.9 micrograms/pair). These findings suggest that: 1) after oral administration, sorbitol is completely absorbed, and 2) that there is a finite accumulation of sorbitol and fructose in the lens in 14 days. Although the radioactive label indicated the exogenous origin of these carbohydrates, it is not certain whether the sorbitol is converted to glucose before entering and accumulating in the lens

Efficient production of succinic acid in immobilized fermentation with crude glycerol from Escherichia coli

Directory of Open Access Journals (Sweden)

Nik Nor Aziati, A.A.

2017-10-01

Full Text Available The increase in the price of commercial succinic acid has necessitated the need for its synthesis from waste materials such as glycerol. Glycerol residue is a waste product of Oleochemical production which is cheaply available and a very good source of carbon. The use of immobilized cells can further reduce the overall cost of the production process. This study primarily aims to produce succinic acid from glycerol residue through the use of immobilized Escherichia coli in a batch fermentation process. The parameters which affect bacterial fermentation process such as the mass substrate, temperature, inoculum size and duration of fermentation were screened using One-Factor-At-a-Time (OFAT method. The result of the screening process shows that a substrate (glycerol concentration of 30 g, inoculum size 20% v/v, and time 4 h produced the maximum succinic acid concentration of 117.99 g/L. The immobilized cells were found to be stable as well as retain their fermentative ability up to the 6th cycle of recycling, thereby presenting as an advantage over the free cell system. Therefore, conclude that using immobilized cells can contribute immensely to the cost-effective production of succinic acid from glycerol residue.

Comparison of Intermolecular Forces in Anhydrous Sorbitol and Solvent Cocrystals.

Science.gov (United States)

Dierks, Teresa M; Korter, Timothy M

2017-08-03

The hygroscopicity of solid sorbitol is important for its utilization as a sweetener in the pharmaceutical and food industries. The molecular foundations of sorbitol hydration characteristics are explored here using two solvated cocrystals, sorbitol-water and sorbitol-pyridine. In this work, solid-state density functional theory and terahertz time-domain spectroscopy were used to evaluate the relative stabilities of these cocrystals as compared to anhydrous sorbitol in terms of conformational and cohesive energies. The modification of the hydrogen-bonding network in crystalline sorbitol by solvent molecules gives new insight into the origins of the notable stability of sorbitol-water as compared to similar solids such as mannitol-water. In particular, the energy analysis reveals that the relative instability of the mannitol hydrate is based primarily in the lack of water-water interactions which provide considerable stabilization in the sorbitol-water crystal.

Caffeic acid production by simultaneous saccharification and fermentation of kraft pulp using recombinant Escherichia coli.

Science.gov (United States)

Kawaguchi, Hideo; Katsuyama, Yohei; Danyao, Du; Kahar, Prihardi; Nakamura-Tsuruta, Sachiko; Teramura, Hiroshi; Wakai, Keiko; Yoshihara, Kumiko; Minami, Hiromichi; Ogino, Chiaki; Ohnishi, Yasuo; Kondo, Ahikiko

2017-07-01

Caffeic acid (3,4-dihydroxycinnamic acid) serves as a building block for thermoplastics and a precursor for biologically active compounds and was recently produced from glucose by microbial fermentation. To produce caffeic acid from inedible cellulose, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactions were compared using kraft pulp as lignocellulosic feedstock. Here, a tyrosine-overproducing Escherichia coli strain was metabolically engineered to produce caffeic acid from glucose by introducing the genes encoding a 4-hydroxyphenyllactate 3-hydroxylase (hpaBC) from Pseudomonas aeruginosa and tyrosine ammonia lyase (fevV) from Streptomyces sp. WK-5344. Using the resulting recombinant strain, the maximum yield of caffeic acid in SSF (233 mg/L) far exceeded that by SHF (37.9 mg/L). In the SSF with low cellulase loads (≤2.5 filter paper unit/g glucan), caffeic acid production was markedly increased, while almost no glucose accumulation was detected, indicating that the E. coli cells experienced glucose limitation in this culture condition. Caffeic acid yield was also negatively correlated with the glucose concentration in the fermentation medium. In SHF, the formation of by-product acetate and the accumulation of potential fermentation inhibitors increased significantly with kraft pulp hydrolysate than filter paper hydrolysate. The combination of these inhibitors had synergistic effects on caffeic acid fermentation at low concentrations. With lower loads of cellulase in SSF, less potential fermentation inhibitors (furfural, 5-hydroxymethyfurfural, and 4-hydroxylbenzoic acid) accumulated in the medium. These observations suggest that glucose limitation in SSF is crucial for improving caffeic acid yield, owing to reduced by-product formation and fermentation inhibitor accumulation.

Persistence of Escherichia coli O157:H7 in dairy fermentation systems.

Science.gov (United States)

Dineen, S S; Takeuchi, K; Soudah, J E; Boor, K J

1998-12-01

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 10(3) CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels > 10(2) CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 10(5) CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

The EspF N-Terminal of Enterohemorrhagic Escherichia coli O157:H7 EDL933w Imparts Stronger Toxicity Effects on HT-29 Cells than the C-Terminal

Directory of Open Access Journals (Sweden)

Xiangyu Wang

2017-09-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC O157:H7 EspF is an important multifunctional protein that destroys the tight junctions of intestinal epithelial cells and promotes host cell apoptosis. However, its molecular mechanism remains elusive. We knocked out the espF sequence (747 bp, ΔespF, N-terminal sequence (219 bp, ΔespFN, and C-terminal sequence (528 bp, ΔespFC separately using the pKD46-mediated λ Red homologous recombination system. Then, we built the corresponding complementation strains, namely, ΔespF/pespF, ΔespFN/pespFN, and ΔespFC/pespFC by overlap PCR, which were used in infecting HT-29 cells and BALB/C mice. The level of reactive oxygen species, cell apoptosis, mitochondrial trans-membrane potential, inflammatory factors, transepithelial electrical resistance (TER, and animal mortality were evaluated by DCFH-DA, double staining of Annexin V-FITC/PI, JC-1 staining, ELISA kit, and a mouse assay. The wild-type (WT, ΔespF, ΔespF/pespF, ΔespFC, ΔespFC/pespFC, ΔespFN, and ΔespFN/pespFN groups exhibited apoptotic rates of 68.3, 27.9, 64.9, 65.7, 73.4, 41.3, and 35.3% respectively, and mean TNF-α expression levels of 428 pg/mL, 342, 466, 446, 381, 383, and 374 pg/mL, respectively. In addition, the apoptotic rates and TNF-α levels of the WT, ΔespF/pespF, and ΔespFC were significantly higher than that of ΔespF, ΔespFN, ΔespFC/pespFC, and ΔespFN/pespFN group (p < 0.05. The N-terminal of EspF resulted in an increase in the number of apoptotic cells, TNF-α secretion, ROS generation, mitochondria apoptosis, and pathogenicity in BalB/c mice. In conclusion, the N-terminal domain of the Enterohemorrhagic E. coli O157:H7 EspF more strongly promotes apoptosis and inflammation than the C-terminal domain.

Electron impact ionization of the gas-phase sorbitol

Science.gov (United States)

Chernyshova, Irina; Markush, Pavlo; Zavilopulo, Anatoly; Shpenik, Otto

2015-03-01

Ionization and dissociative ionization of the sorbitol molecule by electron impact have been studied using two different experimental methods. In the mass range of m/ z = 10-190, the mass spectra of sorbitol were recorded at the ionizing electron energies of 70 and 30 eV. The ion yield curves for the fragment ions have been analyzed and the appearance energies of these ions have been determined. The relative total ionization cross section of the sorbitol molecule was measured using monoenergetic electron beam. Possible fragmentation pathways for the sorbitol molecule were proposed.

Sorbitol dehydrogenase is a cytosolic protein required for sorbitol metabolism in Arabidopsis thaliana.

Science.gov (United States)

Aguayo, María Francisca; Ampuero, Diego; Mandujano, Patricio; Parada, Roberto; Muñoz, Rodrigo; Gallart, Marta; Altabella, Teresa; Cabrera, Ricardo; Stange, Claudia; Handford, Michael

2013-05-01

Sorbitol is converted to fructose in Rosaceae species by SORBITOL DEHYDROGENASE (SDH, EC 1.1.1.14), especially in sink organs. SDH has also been found in non-Rosaceae species and here we show that the protein encoded by At5g51970 in Arabidopsis thaliana (L.) Heynh. possesses the molecular characteristics of an SDH. Using a green fluorescent protein-tagged version and anti-SDH antisera, we determined that SDH is cytosolically localized, consistent with bioinformatic predictions. We also show that SDH is widely expressed, and that SDH protein accumulates in both source and sink organs. In the presence of NAD+, recombinant SDH exhibited greatest oxidative activity with sorbitol, ribitol and xylitol as substrates; other sugar alcohols were oxidized to a lesser extent. Under standard growth conditions, three independent sdh- mutants developed as wild-type. Nevertheless, all three exhibited reduced dry weight and primary root length compared to wild-type when grown in the presence of sorbitol. Additionally, under short-day conditions, the mutants were more resistant to dehydration stress, as shown by a reduced loss of leaf water content when watering was withheld, and a greater survival rate on re-watering. This evidence suggests that limitations in the metabolism of sugar alcohols alter the growth of Arabidopsis and its response to drought. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Analysis of l-glutamic acid fermentation by using a dynamic metabolic simulation model of Escherichia coli

OpenAIRE

Nishio, Yousuke; Ogishima, Soichi; Ichikawa, Masao; Yamada, Yohei; Usuda, Yoshihiro; Masuda, Tadashi; Tanaka, Hiroshi

2013-01-01

Background Understanding the process of amino acid fermentation as a comprehensive system is a challenging task. Previously, we developed a literature-based dynamic simulation model, which included transcriptional regulation, transcription, translation, and enzymatic reactions related to glycolysis, the pentose phosphate pathway, the tricarboxylic acid (TCA) cycle, and the anaplerotic pathway of Escherichia coli. During simulation, cell growth was defined such as to reproduce the experimental...

Sorbitol-fermenting Bifidobacteria are indicators of very recent human faecal pollution in streams and groundwater habitats in urban tropical lowlands

Science.gov (United States)

2010-01-01

Sorbitol-fermenting Bifidobacteria (SFB) proved to be an excellent indicator of very recent human faecal pollution (hours to days) in the investigated tropical stream and groundwater habitats. SFB were recovered from human faeces and sources potentially contaminated with human excreta. SFB were undetectable in animal faeces and environmental samples not contaminated with human faeces. Microcosm studies demonstrated a rapid die-off rate in groundwater (T90 value 0.6 days) and stream water (T90 value 0.9–1.7 days). Discrimination sensitivity analysis, including E. coli, faecal coliforms, total coliforms and Clostridium perfringens spores, revealed high ability of SFB to distinguish differing levels of faecal pollution especially for streams although high background levels of interfering bacteria can complicate its recovery on the used medium. Due to its faster die-off, as compared to many waterborne pathogens, SFB cannot replace microbiological standard parameters for routine water quality monitoring but it is highly recommendable as a specific and complementary tool when human faecal pollution has to be localized or verified. Because of its exclusive faecal origin and human specificity it seems also worthwhile to include SFB in future risk evaluation studies at tropical water resources in order to evaluate under which situations risks of infection may be indicated. PMID:20375476

Sorbitol dehydrogenase of Aspergillus niger, SdhA, is part of the oxido-reductive D-galactose pathway and essential for D-sorbitol catabolism.

Science.gov (United States)

Koivistoinen, Outi M; Richard, Peter; Penttilä, Merja; Ruohonen, Laura; Mojzita, Dominik

2012-02-17

In filamentous fungi D-galactose can be catabolised through the oxido-reductive and/or the Leloir pathway. In the oxido-reductive pathway D-galactose is converted to d-fructose in a series of steps where the last step is the oxidation of d-sorbitol by an NAD-dependent dehydrogenase. We identified a sorbitol dehydrogenase gene, sdhA (JGI53356), in Aspergillus niger encoding a medium chain dehydrogenase which is involved in D-galactose and D-sorbitol catabolism. The gene is upregulated in the presence of D-galactose, galactitol and D-sorbitol. An sdhA deletion strain showed reduced growth on galactitol and growth on D-sorbitol was completely abolished. The purified enzyme converted D-sorbitol to D-fructose with K(m) of 50±5 mM and v(max) of 80±10 U/mg. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Functional assignment of gene AAC16202.1 from Rhodobacter capsulatus SB1003: new insights into the bacterial SDR sorbitol dehydrogenases family.

Science.gov (United States)

Sola-Carvajal, Agustín; García-García, María Inmaculada; Sánchez-Carrón, Guiomar; García-Carmona, Francisco; Sánchez-Ferrer, Alvaro

2012-11-01

Short-chain dehydrogenases/reductases (SDR) constitute one of the largest enzyme superfamilies with over 60,000 non-redundant sequences in the database, many of which need a correct functional assignment. Among them, the gene AAC16202.1 (NCBI) from Rhodobacter capsulatus SB1003 has been assigned in Uniprot both as a sorbitol dehydrogenase (#D5AUY1) and, as an N-acetyl-d-mannosamine dehydrogenase (#O66112), both enzymes being of biotechnological interest. When the gene was overexpressed in Escherichia coli Rosetta (DE3)pLys, the purified enzyme was not active toward N-acetyl-d-mannosamine, whereas it was active toward d-sorbitol and d-fructose. However, the relative activities toward xylitol and l-iditol (0.45 and 6.9%, respectively) were low compared with that toward d-sorbitol. Thus, the enzyme could be considered sorbitol dehydrogenase (SDH) with very low activity toward xylitol, which could increase its biotechnological interest for determining sorbitol without the unspecific cross-determination of added xylitol in food and pharma compositions. The tetrameric enzyme (120 kDa) showed similar catalytic efficiency (2.2 × 10(3) M(-1) s(-1)) to other sorbitol dehydrogenases for d-sorbitol, with an optimum pH of 9.0 and an optimum temperature of 37 °C. The enzyme was also more thermostable than other reported SDH, ammonium sulfate being the best stabilizer in this respect, increasing the melting temperature (T(m)) up to 52.9 °C. The enzyme can also be considered as a new member of the Zn(2+) independent SDH family since no effect on activity was detected in the presence of divalent cations or chelating agents. Finally, its in silico analysis enabled the specific conserved sequence blocks that are the fingerprints of bacterial sorbitol dehydrogenases and mainly located at C-terminal of the protein, to be determined for the first time. This knowledge will facilitate future data curation of present databases and a better functional assignment of newly described

Analysis of L-glutamic acid fermentation by using a dynamic metabolic simulation model of Escherichia coli.

Science.gov (United States)

Nishio, Yousuke; Ogishima, Soichi; Ichikawa, Masao; Yamada, Yohei; Usuda, Yoshihiro; Masuda, Tadashi; Tanaka, Hiroshi

2013-09-22

Understanding the process of amino acid fermentation as a comprehensive system is a challenging task. Previously, we developed a literature-based dynamic simulation model, which included transcriptional regulation, transcription, translation, and enzymatic reactions related to glycolysis, the pentose phosphate pathway, the tricarboxylic acid (TCA) cycle, and the anaplerotic pathway of Escherichia coli. During simulation, cell growth was defined such as to reproduce the experimental cell growth profile of fed-batch cultivation in jar fermenters. However, to confirm the biological appropriateness of our model, sensitivity analysis and experimental validation were required. We constructed an L-glutamic acid fermentation simulation model by removing sucAB, a gene encoding α-ketoglutarate dehydrogenase. We then performed systematic sensitivity analysis for L-glutamic acid production; the results of this process corresponded with previous experimental data regarding L-glutamic acid fermentation. Furthermore, it allowed us to predicted the possibility that accumulation of 3-phosphoglycerate in the cell would regulate the carbon flux into the TCA cycle and lead to an increase in the yield of L-glutamic acid via fermentation. We validated this hypothesis through a fermentation experiment involving a model L-glutamic acid-production strain, E. coli MG1655 ΔsucA in which the phosphoglycerate kinase gene had been amplified to cause accumulation of 3-phosphoglycerate. The observed increase in L-glutamic acid production verified the biologically meaningful predictive power of our dynamic metabolic simulation model. In this study, dynamic simulation using a literature-based model was shown to be useful for elucidating the precise mechanisms involved in fermentation processes inside the cell. Further exhaustive sensitivity analysis will facilitate identification of novel factors involved in the metabolic regulation of amino acid fermentation.

Role of major surface structures of Escherichia coli O157:H7 in initial attachment to biotic and abiotic surfaces

Science.gov (United States)

Infection by human pathogens through fresh, minimally processed produce and solid plant-derived foods is a major concern of U.S. and global food industry and public health services. The enterohemorrhagic Escherichia coli O157:H7 is a frequent and potent food borne pathogen that causes severe disease...

Direct catalytic production of sorbitol from waste cellulosic materials.

Science.gov (United States)

Ribeiro, Lucília Sousa; Órfão, José J de Melo; Pereira, Manuel Fernando Ribeiro

2017-05-01

Cotton wool, cotton textile, tissue paper and printing paper, all potential waste cellulosic materials, were directly converted to sorbitol using a Ru/CNT catalyst in the presence of H 2 and using only water as solvent, without any acids. Conversions up to 38% were attained for the raw substrates, with sorbitol yields below 10%. Ball-milling of the materials disrupted their crystallinity, allowing reaching 100% conversion of cotton wool, cotton textile and tissue paper after 4h, with sorbitol yields around 50%. Mix-milling these materials with the catalyst greatly enhanced their conversion rate, and the materials were efficiently converted to sorbitol with a yield around 50% in 2h. However, ball- and mix-milled printing paper presented a conversion of only 50% after 5h, with sorbitol yields of 7%. Amounts of sorbitol of 0.525, 0.511 and 0.559g could be obtained from 1g of cotton wool, cotton textile and tissue paper, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sorbitol crystallization-induced aggregation in frozen mAb formulations.

Science.gov (United States)

Piedmonte, Deirdre Murphy; Hair, Alison; Baker, Priti; Brych, Lejla; Nagapudi, Karthik; Lin, Hong; Cao, Wenjin; Hershenson, Susan; Ratnaswamy, Gayathri

2015-02-01

Sorbitol crystallization-induced aggregation of mAbs in the frozen state was evaluated. The effect of protein aggregation resulting from sorbitol crystallization was measured as a function of formulation variables such as protein concentration and pH. Long-term studies were performed on both IgG1 and IgG2 mAbs over the protein concentration range of 0.1-120 mg/mL. Protein aggregation was measured by size-exclusion HPLC (SE-HPLC) and further characterized by capillary-electrophoresis SDS. Sorbitol crystallization was monitored and characterized by subambient differential scanning calorimetry and X-ray diffraction. Aggregation due to sorbitol crystallization is inversely proportional to both protein concentration and formulation pH. At high protein concentrations, sorbitol crystallization was suppressed, and minimal aggregation by SE-HPLC resulted, presumably because of self-stabilization of the mAbs. The glass transition temperature (Tg ') and fragility index measurements were made to assess the influence of molecular mobility on the crystallization of sorbitol. Tg ' increased with increasing protein concentration for both mAbs. The fragility index decreased with increasing protein concentration, suggesting that it is increasingly difficult for sorbitol to crystallize at high protein concentrations. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Effects of antecedent fermentative and respiratory growth on the detection of chloramine-stressed Escherichia coil and Salmonella typhimurium.

Science.gov (United States)

Thunberg, R L; Sexstone, A J; Calabrese, J P; Bissonnette, G K

2001-08-01

In vitro laboratory studies were performed to assess the effects of antecedent growth conditions on the recovery of Escherichia coli ATCC 25922 and Salmonella typhimurium ATCC 14028 following chloramine disinfection. Six- and 18-h cultures of each organism were grown under aerobic, fermentative, and nitrate-reducing conditions prior to disinfection. At predetermined time intervals during a 10-min exposure to chloramine, survivors were surface plated on nonselective recovery media to determine C(n)t values. It was observed that nitrate-reducing growth predisposed the test organisms towards an increased sensitivity to chloramine stress over cells grown under fermentation or aerobic conditions (p < 0.01).

Feed Fermentation with Reuteran- and Levan-Producing Lactobacillus reuteri Reduces Colonization of Weanling Pigs by Enterotoxigenic Escherichia coli.

Science.gov (United States)

Yang, Yan; Galle, Sandra; Le, Minh Hong Anh; Zijlstra, Ruurd T; Gänzle, Michael G

2015-09-01

This study determined the effect of feed fermentation with Lactobacillus reuteri on growth performance and the abundance of enterotoxigenic Escherichia coli (ETEC) in weanling piglets. L. reuteri strains produce reuteran or levan, exopolysaccharides that inhibit ETEC adhesion to the mucosa, and feed fermentation was conducted under conditions supporting exopolysaccharide formation and under conditions not supporting exopolysaccharide formation. Diets were chosen to assess the impact of organic acids and the impact of viable L. reuteri bacteria. Fecal samples were taken throughout 3 weeks of feeding; at the end of the 21-day feeding period, animals were euthanized to sample the gut digesta. The feed intake was reduced in pigs fed diets containing exopolysaccharides; however, feed efficiencies did not differ among the diets. Quantification of L. reuteri by quantitative PCR (qPCR) detected the two strains used for feed fermentation throughout the intestinal tract. Quantification of E. coli and ETEC virulence factors by qPCR demonstrated that fermented diets containing reuteran significantly (P reuteri reduced the level of colonization of weaning piglets with ETEC, and feed fermentation supplied concentrations of reuteran that may specifically contribute to the effect on ETEC. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Pra Desain Pabrik Sorbitol dari Tepung Tapioka dengan Hidrogenasi Katalitik

Directory of Open Access Journals (Sweden)

Hellen Kartika Dewi

2014-03-01

Full Text Available Sorbitol yang dikenal juga sebagai glusitol, adalah suatu gula alkohol yang dimetabolisme lambat di dalam tubuh. Sorbitol banyak digunakan sebagai bahan baku untuk industri barang konsumsi dan makanan seperti pasta gigi, permen, kosmetika, farmasi, vitamin C, termasuk industri tekstil dan kulit. Pembuatan sorbitol dari bahan baku tepung tapioka. Pabrik sorbitol ini direncanakan akan didirikan di Propinsi Jawa Tengah tepatnya di Kabupaten Batang dengan kapasitas produksi 30.000 ton/tahun. Proses produksi Sorbitol menggunakan proses hidrogenasi katalitik. Pembuatan sorbitol dari bahan baku pati melalui dua tahap proses utama yaitu proses perubahan starch menjadi glukosa melalui hidrolisa double enzym. Enzim yang digunakan yaitu α-amylase dan glukoamylase. Proses hidrogenasi katalitik dilakukan dengan mereaksikan larutan dekstrose dan gas hidrogen bertekanan tinggi dengan menambahkan katalis nikel dalam reaktor (Reaktor Hidrogenasi. Gas hidrogen masuk dari bawah reaktor secara bubbling dan larutan dekstrose diumpankan dari atas reaktor sehingga kontak yang terjadi semakin baik. Sorbitol yang di hasilkan dalam pradesain pabrik sorbitol ini dengan konsentrasi 58,2%. Pendirian pabrik sorbitol memerlukan biaya investasi modal tetap (fixed capital sebesar Rp 168.801.192.952, modal kerja (working capital  Rp 29.788.445.815, investasi total Rp 198.589.638.767, Biaya produksi per tahun Rp 368.832.813.809 dan  hasil penjualan per tahun Rp 540.000.078.750. Dari analisa ekonomi didapatkan BEP sebesar 26,32%. ROI sesudah pajak 48,5 %, POT sesudah pajak 2,14 tahun. Dari segi teknis dan ekonomis, pabrik ini layak untuk didirikan.

Analysis of l-glutamic acid fermentation by using a dynamic metabolic simulation model of Escherichia coli

Science.gov (United States)

2013-01-01

Background Understanding the process of amino acid fermentation as a comprehensive system is a challenging task. Previously, we developed a literature-based dynamic simulation model, which included transcriptional regulation, transcription, translation, and enzymatic reactions related to glycolysis, the pentose phosphate pathway, the tricarboxylic acid (TCA) cycle, and the anaplerotic pathway of Escherichia coli. During simulation, cell growth was defined such as to reproduce the experimental cell growth profile of fed-batch cultivation in jar fermenters. However, to confirm the biological appropriateness of our model, sensitivity analysis and experimental validation were required. Results We constructed an l-glutamic acid fermentation simulation model by removing sucAB, a gene encoding α-ketoglutarate dehydrogenase. We then performed systematic sensitivity analysis for l-glutamic acid production; the results of this process corresponded with previous experimental data regarding l-glutamic acid fermentation. Furthermore, it allowed us to predicted the possibility that accumulation of 3-phosphoglycerate in the cell would regulate the carbon flux into the TCA cycle and lead to an increase in the yield of l-glutamic acid via fermentation. We validated this hypothesis through a fermentation experiment involving a model l-glutamic acid-production strain, E. coli MG1655 ΔsucA in which the phosphoglycerate kinase gene had been amplified to cause accumulation of 3-phosphoglycerate. The observed increase in l-glutamic acid production verified the biologically meaningful predictive power of our dynamic metabolic simulation model. Conclusions In this study, dynamic simulation using a literature-based model was shown to be useful for elucidating the precise mechanisms involved in fermentation processes inside the cell. Further exhaustive sensitivity analysis will facilitate identification of novel factors involved in the metabolic regulation of amino acid fermentation. PMID

Sorbitol counteracts high hydrostatic pressure-induced denaturation of inulin fructotransferase.

Science.gov (United States)

Li, Yungao; Miao, Ming; Liu, Miao; Jiang, Bo; Zhang, Tao; Chen, Xiangyin

2014-09-01

Inulin fructotransferase (IFTase), a novel hydrolase for inulin, was exposed to high hydrostatic pressure (HHP) at 400 and 600 MPa for 15 min in the presence or absence of sorbitol. Sorbitol protected the enzyme against HHP-induced activity loss. The relative residual activity increased nearly 3.1- and 3.8-fold in the presence of 3 mol/L sorbitol under 400 MPa and 600 MPa for 15 min, respectively. Circular dichroism results indicated that the original chaotic unfolding conformation of the enzyme under HHP shifted toward more ordered and impact with 3 mol/L sorbitol. Fluorescence and UV spectra results suggested that sorbitol prevented partially the unfolding of the enzyme and stabilized the conformation under high pressure. These results might be attributed to the binding of sorbitol on the surface of IFTase to rearrange and strengthen intra- and intermolecular hydrogen bonds. Copyright © 2014 Elsevier B.V. All rights reserved.

The EspF N-Terminal of Enterohemorrhagic Escherichia coli O157:H7 EDL933w Imparts Stronger Toxicity Effects on HT-29 Cells than the C-Terminal.

Science.gov (United States)

Wang, Xiangyu; Du, Yanli; Hua, Ying; Fu, Muqing; Niu, Cong; Zhang, Bao; Zhao, Wei; Zhang, Qiwei; Wan, Chengsong

2017-01-01

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 EspF is an important multifunctional protein that destroys the tight junctions of intestinal epithelial cells and promotes host cell apoptosis. However, its molecular mechanism remains elusive. We knocked out the espF sequence (747 bp, Δ espF ), N-terminal sequence (219 bp, Δ espF N ), and C-terminal sequence (528 bp, Δ espF C ) separately using the pKD46-mediated λ Red homologous recombination system. Then, we built the corresponding complementation strains, namely, Δ espF/pespF , Δ espF N /pespF N , and Δ espF C /pespF C by overlap PCR, which were used in infecting HT-29 cells and BALB/C mice. The level of reactive oxygen species, cell apoptosis, mitochondrial trans-membrane potential, inflammatory factors, transepithelial electrical resistance (TER), and animal mortality were evaluated by DCFH-DA, double staining of Annexin V-FITC/PI, JC-1 staining, ELISA kit, and a mouse assay. The wild-type (WT), Δ espF , Δ espF/pespF , Δ espF C , Δ espF C /pespF C , Δ espF N , and Δ espF N /pespF N groups exhibited apoptotic rates of 68.3, 27.9, 64.9, 65.7, 73.4, 41.3, and 35.3% respectively, and mean TNF-α expression levels of 428 pg/mL, 342, 466, 446, 381, 383, and 374 pg/mL, respectively. In addition, the apoptotic rates and TNF-α levels of the WT, Δ espF/pespF , and Δ espF C were significantly higher than that of Δ espF , Δ espF N , Δ espF C /pespF C , and Δ espF N /pespF N group ( p < 0.05). The N-terminal of EspF resulted in an increase in the number of apoptotic cells, TNF-α secretion, ROS generation, mitochondria apoptosis, and pathogenicity in BalB/c mice. In conclusion, the N-terminal domain of the Enterohemorrhagic E. coli O157:H7 EspF more strongly promotes apoptosis and inflammation than the C-terminal domain.

Non-climacteric ripening and sorbitol homeostasis in plum fruits.

Science.gov (United States)

Kim, Ho-Youn; Farcuh, Macarena; Cohen, Yuval; Crisosto, Carlos; Sadka, Avi; Blumwald, Eduardo

2015-02-01

During ripening fruits undergo several physiological and biochemical modifications that influence quality-related properties, such as texture, color, aroma and taste. We studied the differences in ethylene and sugar metabolism between two genetically related Japanese plum cultivars with contrasting ripening behaviors. 'Santa Rosa' (SR) behaved as a typical climacteric fruit, while the bud sport mutant 'Sweet Miriam' (SM) displayed a non-climacteric ripening pattern. SM fruit displayed a delayed ripening that lasted 120 days longer than that of the climacteric fruit. At the full-ripe stage, both cultivars reached similar final size and weight but the non-climacteric fruits were firmer than the climacteric fruits. Fully ripe non-climacteric plum fruits, showed an accumulation of sorbitol that was 2.5 times higher than that of climacteric fruits, and the increase in sorbitol were also paralleled to an increase in sucrose catabolism. These changes were highly correlated with decreased activity and expression of NAD(+)-dependent sorbitol dehydrogenase and sorbitol oxidase and increased sorbitol-6-phosphate dehydrogenase activity, suggesting an enhanced sorbitol synthesis in non-climacteric fruits. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The effects of urea, guanidinium chloride and sorbitol on porphyrin ...

Indian Academy of Sciences (India)

This paper compares the inhibition effect of porphyrin aggregation in the presence of urea, guanidinium chloride (Gdn) and sorbitol by molecular dynamics simulation. It demonstrates that porphyrin aggregation increases in sorbitol, but decreases towards addition of urea and Gdn. It shows that urea, Gdn and sorbitol can ...

Engineering furfural tolerance in Escherichia coli improves the fermentation of lignocellulosic sugars into renewable chemicals.

Science.gov (United States)

Wang, Xuan; Yomano, Lorraine P; Lee, James Y; York, Sean W; Zheng, Huabao; Mullinnix, Michael T; Shanmugam, K T; Ingram, Lonnie O

2013-03-05

Pretreatments such as dilute acid at elevated temperature are effective for the hydrolysis of pentose polymers in hemicellulose and also increase the access of enzymes to cellulose fibers. However, the fermentation of resulting syrups is hindered by minor reaction products such as furfural from pentose dehydration. To mitigate this problem, four genetic traits have been identified that increase furfural tolerance in ethanol-producing Escherichia coli LY180 (strain W derivative): increased expression of fucO, ucpA, or pntAB and deletion of yqhD. Plasmids and integrated strains were used to characterize epistatic interactions among traits and to identify the most effective combinations. Furfural resistance traits were subsequently integrated into the chromosome of LY180 to construct strain XW129 (LY180 ΔyqhD ackA::PyadC'fucO-ucpA) for ethanol. This same combination of traits was also constructed in succinate biocatalysts (Escherichia coli strain C derivatives) and found to increase furfural tolerance. Strains engineered for resistance to furfural were also more resistant to the mixture of inhibitors in hemicellulose hydrolysates, confirming the importance of furfural as an inhibitory component. With resistant biocatalysts, product yields (ethanol and succinate) from hemicellulose syrups were equal to control fermentations in laboratory media without inhibitors. The combination of genetic traits identified for the production of ethanol (strain W derivative) and succinate (strain C derivative) may prove useful for other renewable chemicals from lignocellulosic sugars.

Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

OpenAIRE

Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

2010-01-01

We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

Reagentless D-sorbitol biosensor based on D-sorbitol dehydrogenase immobilized in a sol-gel carbon nanotubes-poly(methylene green) composite.

Science.gov (United States)

Wang, Zhijie; Etienne, Mathieu; Urbanova, Veronika; Kohring, Gert-Wieland; Walcarius, Alain

2013-04-01

A reagentless D-sorbitol biosensor based on NAD-dependent D-sorbitol dehydrogenase (DSDH) immobilized in a sol-gel carbon nanotubes-poly(methylene green) composite has been developed. It was prepared by durably immobilizing the NAD(+) cofactor with DSDH in a sol-gel thin film on the surface of carbon nanotubes functionalized with poly(methylene green). This device enables selective determination of D-sorbitol at 0.2 V with a sensitivity of 8.7 μA mmol(-1) L cm(-2) and a detection limit of 0.11 mmol L(-1). Moreover, this biosensor has excellent operational stability upon continuous use in hydrodynamic conditions.

Determining the relative contribution and hierarchy of qseBC and hha in the regulation of flagellar motility of Escherichia coli O157:H7

Science.gov (United States)

In a recent study we demonstrated that in comparison to the wild-type enterohemorrhagic Escherichia coli (EHEC) O157:H7, a motility-compromised hha deletion mutant with an up-regulated type III secretion system and increased secretion of adherence proteins showed reduced fecal shedding in cattle. In...

Enteroaggregative, Shiga Toxin-Producing Escherichia coli O111:H2 Associated with an Outbreak of Hemolytic-Uremic Syndrome

Science.gov (United States)

Morabito, Stefano; Karch, Helge; Mariani-Kurkdjian, Patrizia; Schmidt, Herbert; Minelli, Fabio; Bingen, Edouard; Caprioli, Alfredo

1998-01-01

Shiga toxin-producing Escherichia coli O111:H2 strains from an outbreak of hemolytic-uremic syndrome showed aggregative adhesion to HEp-2 cells and harbored large plasmids which hybridized with the enteroaggregative E. coli probe PCVD432. These strains present a novel combination of virulence factors and might be as pathogenic to humans as the classic enterohemorrhagic E. coli. PMID:9508328

Development of a rapid agglutination latex test for diagnosis of enteropathogenic and enterohemorrhagic Escherichia coli infection in developing world: defining the biomarker, antibody and method.

Directory of Open Access Journals (Sweden)

Letícia B Rocha

2014-09-01

Full Text Available Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC/EHEC are human intestinal pathogens responsible for diarrhea in both developing and industrialized countries. In research laboratories, EPEC and EHEC are defined on the basis of their pathogenic features; nevertheless, their identification in routine laboratories is expensive and laborious. Therefore, the aim of the present work was to develop a rapid and simple assay for EPEC/EHEC detection. Accordingly, the EPEC/EHEC-secreted proteins EspA and EspB were chosen as target antigens.First, we investigated the ideal conditions for EspA/EspB production/secretion by ELISA in a collection of EPEC/EHEC strains after cultivating bacterial isolates in Dulbecco's modified Eagle's medium (DMEM or DMEM containing 1% tryptone or HEp-2 cells-preconditioned DMEM, employing either anti-EspA/anti-EspB polyclonal or monoclonal antibodies developed and characterized herein. Subsequently, a rapid agglutination latex test (RALT was developed and tested with the same collection of bacterial isolates.EspB was defined as a biomarker and its corresponding monoclonal antibody as the tool for EPEC/EHEC diagnosis; the production of EspB was better in DMEM medium. RALT assay has the sensitivity and specificity required for high-impact diagnosis of neglected diseases in the developing world.RALT assay described herein can be considered an alternative assay for diarrhea diagnosis in low-income countries since it achieved 97% sensitivity, 98% specificity and 97% efficiency.

Optimization of fermentation conditions for the production of curcumin by engineered Escherichia coli.

Science.gov (United States)

Couto, Márcia R; Rodrigues, Joana L; Rodrigues, Lígia R

2017-08-01

Curcumin is a plant secondary metabolite with outstanding therapeutic effects. Therefore, there is a great interest in developing new strategies to produce this high-value compound in a cheaper and environmentally friendly way. Curcumin heterologous production in Escherichia coli using artificial biosynthetic pathways was previously demonstrated using synthetic biology approaches. However, the culturing conditions to produce this compound were not optimized and so far only a two-step fermentation process involving the exchange of culture medium allowed high concentrations of curcumin to be obtained, which limits its production at an industrial scale. In this study, the culturing conditions to produce curcumin were evaluated and optimized. In addition, it was concluded that E. coli BL21 allows higher concentrations of curcumin to be produced than E. coli K-12 strains. Different isopropyl β-d-thiogalactopyranoside concentrations, time of protein expression induction and substrate type and concentration were also evaluated. The highest curcumin production obtained was 959.3 µM (95.93% of per cent yield), which was 3.1-fold higher than the highest concentration previously reported. This concentration was obtained using a two-stage fermentation with lysogeny broth (LB) and M9. Moreover, terrific broth was also demonstrated to be a very interesting alternative medium to produce curcumin because it also led to high concentrations (817.7 µM). The use of this single fermentation medium represents an advantage at industrial scale and, although the final production is lower than that obtained with the LB-M9 combination, it leads to a significantly higher production of curcumin in the first 24 h of fermentation. This study allowed obtaining the highest concentrations of curcumin reported so far in a heterologous organism and is of interest for all of those working with the heterologous production of curcuminoids, other complex polyphenolic compounds or plant secondary

A Genetic Algorithms Based Approach for Identification of Escherichia coli Fed-batch Fermentation

Directory of Open Access Journals (Sweden)

Olympia Roeva

2004-10-01

Full Text Available This paper presents the use of genetic algorithms for identification of Escherichia coli fed-batch fermentation process. Genetic algorithms are a directed random search technique, based on the mechanics of natural selection and natural genetics, which can find the global optimal solution in complex multidimensional search space. The dynamic behavior of considered process has known nonlinear structure, described with a system of deterministic nonlinear differential equations according to the mass balance. The parameters of the model are estimated using genetic algorithms. Simulation examples for demonstration of the effectiveness and robustness of the proposed identification scheme are included. As a result, the model accurately predicts the process of cultivation of E. coli.

Direct sorbitol proton exchange membrane fuel cell using moderate catalyst loadings

International Nuclear Information System (INIS)

Oyarce, Alejandro; Gonzalez, Carlos; Lima, Raquel Bohn; Lindström, Rakel Wreland; Lagergren, Carina; Lindbergh, Göran

2014-01-01

Highlights: •The performance of a direct sorbitol fuel cell was evaluated at different temperatures. •The performance was compared to the performance of a direct glucose fuel cell. •The mass specific peak power density of the direct sorbitol fuel cell was 3.6 mW mg −1 totalcatalystloading at 80 °C. •Both sorbitol and glucose fuel cell suffer from deactivation. -- Abstract: Recent progress in biomass hydrolysis has made it interesting to study the use of sorbitol for electricity generation. In this study, sorbitol and glucose are used as fuels in proton exchange membrane fuel cells having 0.9 mg cm −2 PtRu/C at the anode and 0.3 mg cm −2 Pt/C at the cathode. The sorbitol oxidation was found to have slower kinetics than glucose oxidation. However, at low temperatures the direct sorbitol fuel cell shows higher performance than the direct glucose fuel cell, attributed to a lower degree of catalyst poisoning. The performance of both fuel cells is considerably improved at higher temperatures. High temperatures lower the poisoning, allowing the direct glucose fuel cell to reach a higher performance than the direct sorbitol fuel cell. The mass specific peak power densities of the direct sorbitol and direct glucose fuel cells at 65 °C was 3.2 mW mg −1 catalyst and 3.5 mW mg −1 catalyst , respectively. Both of these values are one order of magnitude larger than mass specific peak power densities of earlier reported direct glucose fuel cells using proton exchange membranes. Furthermore, both the fuel cells showed a considerably decrease in performance with time, which is partially attributed to sorbitol and glucose crossover poisoning the Pt/C cathode

Fermented soya bean (tempe) extracts reduce adhesion of enterotoxigenic Escherichia coli to intestinal epithelial cells.

Science.gov (United States)

Roubos-van den Hil, P J; Nout, M J R; Beumer, R R; van der Meulen, J; Zwietering, M H

2009-03-01

This study aimed to investigate the effect of processed soya bean, during the successive stages of tempe fermentation and different fermentation times, on adhesion of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal brush border cells as well as Caco-2 intestinal epithelial cells; and to clarify the mechanism of action. Tempe was prepared at controlled laboratory scale using Rhizopus microsporus var. microsporus as the inoculum. Extracts of raw, soaked and cooked soya beans reduced ETEC adhesion to brush border cells by 40%. Tempe extracts reduced adhesion by 80% or more. ETEC adhesion to Caco-2 cells reduced by 50% in the presence of tempe extracts. ETEC K88 bacteria were found to interact with soya bean extracts, and this may contribute to the observed decrease of ETEC adhesion to intestinal epithelial cells. Fermented soya beans (tempe) reduce the adhesion of ETEC to intestinal epithelial cells of pig and human origin. This reduced adhesion is caused by an interaction between ETEC K88 bacteria and soya bean compounds. The results strengthen previous observations on the anti-diarrhoeal effect of tempe. This effect indicates that soya-derived compounds may reduce adhesion of ETEC to intestinal cells in pigs as well as in humans and prevent against diarrhoeal diseases.

Mathematical modeling of the fermentation of acid-hydrolyzed pyrolytic sugars to ethanol by the engineered strain Escherichia coli ACCC 11177.

Science.gov (United States)

Chang, Dongdong; Yu, Zhisheng; Islam, Zia Ul; Zhang, Hongxun

2015-05-01

Pyrolysate from waste cotton was acid hydrolyzed and detoxified to yield pyrolytic sugars, which were fermented to ethanol by the strain Escherichia coli ACCC 11177. Mathematical models based on the fermentation data were also constructed. Pyrolysate containing an initial levoglucosan concentration of 146.34 g/L gave a glucose yield of 150 % after hydrolysis, suggesting that other compounds were hydrolyzed to glucose as well. Ethyl acetate-based extraction of bacterial growth inhibitors with an ethyl acetate/hydrolysate ratio of 1:0.5 enabled hydrolysate fermentation by E. coli ACCC 11177, without a standard absorption treatment. Batch processing in a fermenter exhibited a maximum ethanol yield and productivity of 0.41 g/g and 0.93 g/L·h(-1), respectively. The cell growth rate (r x ) was consistent with a logistic equation [Formula: see text], which was determined as a function of cell growth (X). Glucose consumption rate (r s ) and ethanol formation rate (r p ) were accurately validated by the equations [Formula: see text] and [Formula: see text], respectively. Together, our results suggest that combining mathematical models with fermenter fermentation processes can enable optimized ethanol production from cellulosic pyrolysate with E. coli. Similar approaches may facilitate the production of other commercially important organic substances.

Succinic acid production by escherichia coli under anaerobic fermentation

International Nuclear Information System (INIS)

El Shafey, H.M.; Meleigy, S.A.

2009-01-01

The effect of alteration of growth conditions, addition of different sodium salts, and irradiation by gamma rays on succinic acid production by E. coli was studied. Twenty one isolates were obtained from buffalo's rumen, and anaerobic screening of the isolated bacterial strains showed the abilities of seventeen strains to produce succinic acid. The two bacterial strains having highest succinic acid production were identified as escherichia coli SP9 and SP16, and were selected for further studies. Results showed that growth conditions yielded highest succinic acid production for the two isolates were: 72 hours incubation, 37 degree c incubation temperature, initial ph of the fermentation medium 6.0,and 3% (v/v)inoculum size. Addition of 5 mm of nine different sodium salts to the fermentation medium showed stimulating effect on succinic acid production of the nine tried sodium salts, sodium carbonate was found to have the highest enhancing effect, especially if used at 15 mm concentration. Gamma irradiation doses tried were in the range of (0.25-1.50 kGy). An enhancing effect on succinic acid production was shown in the range of 0.25-0.75 kGy with a maximal production at 0.75 kGy (giving 8.36% increase) for e.coli SP9, and in the range of 0.25-1.00 kGy with a maximal production at 1.0 kGy (7.60% increase) for e.coli SP16. higher gamma doses led to a decrease in the enhancing effect. An overall increase in the succinic acid yield of 79.45% and 94.26% for e. coli SP9 and SP16, respectively, was achieved in implicating all optimized factors for succinic acid production in one time

Effect of sorbitol on dough rheology and quality of sugar replaced cookies

Directory of Open Access Journals (Sweden)

Mohammad Ali Shariati

2018-02-01

Full Text Available A high amount of sugar is used in bakery products, which may cause diabetes, high blood glucose levels and obesity. Due to these reasons, sugar is being replaced with substitutes. There is different carbohydrate-based sugar substitutes (polyols that can efficiently replace sugar. Among polyols, sorbitol is an efficient replacer that can mimic sugar with minimal effects on cookie quality. Effects of different sorbitol levels (0 to 12.5% were seen on the dough rheology. Mixographic studies showed that peak height and mixing time reduced with the addition of sorbitol. Farinographic studies showed that water absorption and the mixing tolerance index of dough reduced with the supplementation of sorbitol, whereas dough development time, arrival time, dough stability time and softening of dough increased. Extensographic studies revealed that sorbitol substitution produced hard, cohesive, adhesive and elastic dough. Sugar in cookies formulations was reduced from 100 to 50% by replacing with sorbitol 0 to 50%. Physical analysis of sorbitol containing cookies showed that the diameter and spread factor of cookies decreased with higher levels of sorbitol, whereas thickness, color, hardness and water activity of cookies increased. The calorific value of cookies decreased with the increasing levels of sorbitol. At upto 20% replacement of sugar, other parameters of cookies were not affected. Sensory evaluation of the cookies showed that hedonic points for sensory evaluation parameters reduced with the increasing levels of sorbitol, T2 (20% replacement showed maximum overall acceptability. Normal 0 false false false EN-GB X-NONE AR-SA

Effects of sorbitol on porcine oocyte maturation and embryo development in vitro.

Science.gov (United States)

Lin, Tao; Zhang, Jin Yu; Diao, Yun Fei; Kang, Jung Won; Jin, Dong-Il

2015-04-01

In the present study, a porcine system was supplemented with sorbitol during in vitro maturation (IVM) or in vitro culture (IVC), and the effects of sorbitol on oocyte maturation and embryonic development following parthenogenetic activation were assessed. Porcine immature oocytes were treated with different concentrations of sorbitol during IVM, and the resultant metaphase II stage oocytes were activated and cultured in porcine zygote medium-3 (PZM-3) for 7 days. No significant difference was observed in cumulus expansion and the nuclear maturation between the control and sorbitol-treated groups, with the exception of the 100 mM group, which showed significantly decreased nuclear maturation and cumulus expansion. There was no significant difference in the intracellular reactive oxygen species (ROS) levels between oocytes matured with 10 or 20 mM sorbitol and control groups, but 50 and 100 mM groups had significantly higher ROS levels than other groups. The 20 mM group showed significant increases in intracellular glutathione and subsequent blastocyst formation rates following parthenogenetic activation compared with the other groups. During IVC, supplementation with sorbitol significantly reduced blastocyst formation and increased the apoptotic index compared with the control. The apoptotic index of blastocysts from the sorbitol-treated group for entire culture period was significantly higher than those of the partially sorbitol-exposed groups. Based on these findings, it can be concluded that the addition of a low concentration of sorbitol (20 mM) during IVM of porcine oocytes benefits subsequent blastocyst development and improves embryo quality, whereas sorbitol supplement during IVC has a negative effect on blastocyst formation.

The Interaction of Sorbitol with Caffeine in Aqueous Solution

OpenAIRE

Tavagnacco, Letizia; Brady, John W.; Cesàro, Attilio

2013-01-01

Molecular dynamics simulations were carried out on a system of caffeine interacting with the sugar alcohol sorbitol. The system examined had a caffeine concentration 0.083 m and a sugar concentration 1.08 m. The trajectories of all molecules in the system were collected over a period of 80 ns and analyzed to determine whether there is any tendency for sorbitol to bind to caffeine, and if so, by what mechanism. The results show that the sorbitol molecules have an affinity for the caffeine mole...

Virulence factors, serogroups and antimicrobial resistance properties of Escherichia coli strains in fermented dairy products.

Science.gov (United States)

Dehkordi, Farhad Safarpoor; Yazdani, Farshad; Mozafari, Jalal; Valizadeh, Yousef

2014-04-07

From a clinical perspective, it is essential to know the microbial safety of fermented dairy products. Doogh and kashk are fermented dairies. These products are used by millions of people but their microbial qualities are unknown. Shiga toxin producing Escherichia coli (STEC) is one of the most commonly detected pathogens in the cases of food poisoning and food-borne illnesses. The present investigation was carried out in order to study the molecular characterization and antimicrobial resistance properties of STEC strains isolated from fermented dairy products. Six hundred fermented dairy samples were collected and immediately transferred to the laboratory. All samples were cultured immediately and those that were E. coli-positive were analyzed for the presence of O157 , O26, O103, O111, O145, O45, O91, O113, O121 and O128 STEC serogroups, tetA, tetB, blaSHV, CITM, cmlA, cat1, aadA1, dfrA1, qnr, aac (3)-IV, sul1 and ereA antibiotic resistance genes and stx1, stx2, eaeA, ehly, cnf1, cnf2, iutA, cdtB, papA, traT, sfaS and fyuA virulence factors using PCR. Antimicrobial susceptibility testing was performed also using disk diffusion methodology with Mueller-Hinton agar. Fifty out of 600 (8.33%) dairy samples harbored E. coli. In addition, yoghurt was the most commonly contaminated dairy. O157 (26%) and O26 (12%) were the most commonly detected serogroups. A significant difference was found between the frequency of Attaching and Effacing E. coli and Enterohaemorrhagic E. coli (P Fermented dairy products can easily become contaminated by antibiotic resistant STEC strains. Our findings should raise awareness about antibiotic resistance in Iran. Clinicians should exercise caution when prescribing antibiotics, especially in veterinary treatments.

Genomic Variability of O Islands Encoding Tellurite Resistance in Enterohemorrhagic Escherichia coli O157:H7 Isolates

Science.gov (United States)

Taylor, Diane E.; Rooker, Michelle; Keelan, Monika; Ng, Lai-King; Martin, Irene; Perna, Nicole T.; Burland, N. T. Valerie; Blattner, Fredrick R.

2002-01-01

Strains of Escherichia coli causing enterohemorrhagic colitis belonging to the O157:H7 lineage are reported to be highly related. Fifteen strains of E. coli O157:H7 and 1 strain of E. coli O46:H− (nonflagellated) were examined for the presence of potassium tellurite resistance (Ter). Ter genes comprising terABCDEF were shown previously to be part of a pathogenicity island also containing integrase, phage, and urease genes. PCR analysis, both conventional and light cycler based, demonstrated that about one-half of the Ter E. coli O157:H7 strains (6 of 15), including the Sakai strain, which has been sequenced, carried a single copy of the Ter genes. Five of the strains, including EDL933, which has also been sequenced, contained two copies. Three other O157:H7 strains and the O46:H− strain did not contain the Ter genes. In strains containing two copies, the Ter genes were associated with the serW and serX tRNA genes. Five O157:H7 strains resembled the O157 Sakai strain whose sequence contained one copy, close to serX, whereas in one isolate the single copy was associated with serW. There was no correlation between Ter and the ability to produce Shiga toxin ST1 or ST2. The Ter MIC for most strains, containing either one or two copies, was 1,024 μg/ml, although for a few the MIC was intermediate, 64 to 128 μg/ml, which could be increased to 512 μg/ml by pregrowth of strains in subinhibitory concentrations of potassium tellurite. Reverse transcriptase PCR analysis confirmed that in most strains Ter was constitutive but that in the rest it was inducible and involved induction of terB and terC genes. Only the terB, -C, -D, and -E genes are required for Ter. The considerable degree of homology between the ter genes on IncH12 plasmid R478, which originated in Serratia marcescens, and pTE53, from an E. coli clinical isolate, suggests that the pathogenicity island was acquired from a plasmid. This work demonstrates diversity among E. coli O157:H7 isolates, at least as

Clonal Diversity of Chilean Isolates of Enterohemorrhagic Escherichia coli from Patients with Hemolytic-Uremic Syndrome, Asymptomatic Subjects, Animal Reservoirs, and Food Products

Science.gov (United States)

Rios, Maritza; Prado, Valeria; Trucksis, Michele; Arellano, Carolina; Borie, Consuelo; Alexandre, Marcela; Fica, Alberto; Levine, Myron M.

1999-01-01

To determine clonal relationship among Chilean enterohemorrhagic Escherichia coli (EHEC) strains from different sources (clinical infections, animal reservoirs, and food), 54 EHEC isolates (44 of E. coli O157, 5 of E. coli O111, and 5 of E. coli O26) were characterized for virulence genes by colony blot hybridization and by pulsed-field gel electrophoresis (PFGE). By colony blotting, 12 different genotypes were identified among the 44 E. coli O157 isolates analyzed, of which the genetic profile stx1+ stx2+ hly+ eae+ was the most prevalent. All human O157 strains that were associated with sporadic cases of hemolytic-uremic syndrome (HUS) carried both the stx1 and stx2 toxin-encoding genes and were eaeA positive. Only 9 of 13 isolates from human controls were stx1+ stx2+, and 8 carried the eaeA gene. Comparison of profiles obtained by PFGE of XbaI-digested genomic DNA showed a great diversity among the E. coli O157 isolates, with 37 different profiles among 39 isolates analyzed. Cluster analysis of PFGE profiles showed a wide distribution of clinical isolates obtained from HUS cases and asymptomatic individuals and a clonal relationship among O157 isolates obtained from HUS cases and pigs. Analysis of virulence genes showed that a correlation exists among strains with the genotype stx1+ stx2+ eae+ and pathogenic potential. A larger difference in the PFGE restriction patterns was observed among the EHEC strains of serogroups O26 and O111. These results indicate that several different EHEC clones circulate in Chile and suggest that pigs are an important animal reservoir for human infections by EHEC. Guidelines have been proposed for better practices in the slaughter of animals in Chile. PMID:9986852

The Interaction of Sorbitol with Caffeine in Aqueous Solution.

Science.gov (United States)

Tavagnacco, Letizia; Brady, John W; Cesàro, Attilio

2013-09-01

Molecular dynamics simulations were carried out on a system of caffeine interacting with the sugar alcohol sorbitol. The system examined had a caffeine concentration 0.083 m and a sugar concentration 1.08 m. The trajectories of all molecules in the system were collected over a period of 80 ns and analyzed to determine whether there is any tendency for sorbitol to bind to caffeine, and if so, by what mechanism. The results show that the sorbitol molecules have an affinity for the caffeine molecules and that the binding occurred by the interaction of the aliphatic hydrophobic protons of the sugar with the caffeine face. This intermolecular association via face-to-face stacking, as suggested by simulation studies, is similar to that found for sucrose and for D-glucose, which overwhelmingly exists in the pyranose ring chair form in aqueous solution, as well as for caffeine-caffeine association. The sorbitol molecules, however, exist as relatively extended chains and are, therefore, topologically quite different from the sugars sucrose and glucose. The comparison of the average conformation of sorbitol molecules bound to caffeine with that of molecules in the free state shows a substantial similarity.

Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

DEFF Research Database (Denmark)

Rumessen, J J; Gudmand-Høyer, E

1987-01-01

Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects....... The mixture caused mild to severe gastrointestinal distress in five subjects. When the carbohydrates were given separately, symptoms were absent. There was a significant correlation between the individual absorption capacities of fructose and of sorbitol. A mixture containing a similar amount of fructose......, but given as sucrose, and a similar amount of sorbitol was further given to four of the seven subjects showing malabsorption of the fructose-sorbitol mixture. Malabsorption now failed to appear, and symptoms were absent. These findings are of potential importance for the understanding of the physiologic...

Characterization of enteropathogenic and Shiga toxin-producing Escherichia coli in cattle and deer in a shared agroecosystem

Directory of Open Access Journals (Sweden)

Pallavi eSingh

2015-04-01

Full Text Available Shiga toxin-producing Escherichia coli (STEC is an important foodborne pathogen. Cattle are suggested to be an important reservoir for STEC; however, these pathogens have also been isolated from other livestock and wildlife. In this study we sought to investigate transmission of STEC, enterohemorrhagic E. coli (EHEC and enteropathogenic E. coli (EPEC between cattle and white-tailed deer in a shared agroecosystem. Cattle feces were collected from 100 animals in a Michigan dairy farm in July 2012, while 163 deer fecal samples were collected during two sampling periods (March and June. The locations of deer fecal pellets were recorded via geographic information system mapping and microsatellite multi-locus genotyping was used to link the fecal samples to individual deer at both time points. Following subculture to sorbitol MacConkey agar and STEC CHROMagar, the pathogens were characterized by serotyping, stx profiling, and PCR-based fingerprinting; multilocus sequence typing (MLST was performed on a subset. STEC and EHEC were cultured from 12% and 16% of cattle, respectively, and EPEC was found in 36%. Deer were significantly less likely to have a pathogen in March versus June where the frequency of STEC, EHEC, and EPEC was 1%, 6% and 22%, respectively. PCR fingerprinting and MLST clustered the cattle- and deer-derived strains together in a phylogenetic tree. Two STEC strains recovered from both animal species shared MLST and fingerprinting profiles, thereby providing evidence of interspecies transmission and highlighting the importance of wildlife species in pathogen shedding dynamics and persistence in the environment and cattle herds.

Fermentation of lactose to ethanol in cheese whey permeate and concentrated permeate by engineered Escherichia coli.

Science.gov (United States)

Pasotti, Lorenzo; Zucca, Susanna; Casanova, Michela; Micoli, Giuseppina; Cusella De Angelis, Maria Gabriella; Magni, Paolo

2017-06-02

Whey permeate is a lactose-rich effluent remaining after protein extraction from milk-resulting cheese whey, an abundant dairy waste. The lactose to ethanol fermentation can complete whey valorization chain by decreasing dairy waste polluting potential, due to its nutritional load, and producing a biofuel from renewable source at the same time. Wild type and engineered microorganisms have been proposed as fermentation biocatalysts. However, they present different drawbacks (e.g., nutritional supplements requirement, high transcriptional demand of recombinant genes, precise oxygen level, and substrate inhibition) which limit the industrial attractiveness of such conversion process. In this work, we aim to engineer a new bacterial biocatalyst, specific for dairy waste fermentation. We metabolically engineered eight Escherichia coli strains via a new expression plasmid with the pyruvate-to-ethanol conversion genes, and we carried out the selection of the best strain among the candidates, in terms of growth in permeate, lactose consumption and ethanol formation. We finally showed that the selected engineered microbe (W strain) is able to efficiently ferment permeate and concentrated permeate, without nutritional supplements, in pH-controlled bioreactor. In the conditions tested in this work, the selected biocatalyst could complete the fermentation of permeate and concentrated permeate in about 50 and 85 h on average, producing up to 17 and 40 g/l of ethanol, respectively. To our knowledge, this is the first report showing efficient ethanol production from the lactose contained in whey permeate with engineered E. coli. The selected strain is amenable to further metabolic optimization and represents an advance towards efficient biofuel production from industrial waste stream.

Improved cryopreservability of stallion sperm using a sorbitol-based freezing extender.

Science.gov (United States)

Pojprasath, T; Lohachit, C; Techakumphu, M; Stout, T; Tharasanit, T

2011-06-01

Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. Sugars are among the important components of a freezing extender and act as non-permeating cryoprotectants. This study aimed to compare the quality of stallion sperm frozen with glucose, fructose or sorbitol-containing freezing extenders. Semen was collected from six stallions of proven fertility and cryopreserved using a freezing extender containing different types of monosaccharide sugars (glucose, fructose or sorbitol). After thawing, the semen was examined for sperm motility, viability, acrosome integrity, plasma membrane functionality and sperm longevity. The fertility of semen frozen in the presence of sorbitol was also tested by artificial insemination. Sperm quality was significantly decreased following freezing and thawing (P sorbitol and glucose (P sorbitol-based extender when examined at 2 and 4 h post-thaw, all of these parameters plus plasma membrane functionality were improved for sperm frozen in the sorbitol extender than in the glucose extender when examined 10 min post-thaw. Two of four mares (50%) inseminated with semen frozen with a sorbitol-containing freezing extender became pregnant. It is concluded that different sugars have different abilities to protect against cryoinjury during freezing and thawing of stallion sperm. This study demonstrated that an extender containing sorbitol as primary sugar can be used to successfully cryopreserve equine sperm; moreover, the quality of frozen-thawed sperm appeared to be better than when glucose or fructose was the principle sugar in the freezing extender. Copyright © 2011 Elsevier Inc. All rights reserved.

Shiga Toxin in Enterohemorrhagic E.coli: regulation and novel antivirulence strategies

Directory of Open Access Journals (Sweden)

Vanessa eSperandio

2012-06-01

Full Text Available Enterohemorrhagic Escherichia coli O157:H7 infects about 73,000 people annually in the USA and is a major cause of outbreaks of bloody diarrhea worldwide, and. In 5 to 7% of the cases, the person infected develops the potentially fatal sequelae hemolytic uremic syndrome (HUS, characterized by acute kidney failure. A hallmark of EHEC pathogenesis and cause of HUS is the production of Shiga toxin (Stx. Stx was first described by Kiyoshi Shiga in Shigella dysenterae serotype I and later discovered in EHEC, and it has been linked to HUS since 1983. Many factors regulate the production of Stx, including temperature, growth phase, antibiotics, reactive oxygen species and quorum sensing. Currently, there is no effective treatment or prophylaxis for HUS. Since the use of antibiotics is not advised to treat EHEC infections because it triggers Stx production, alternative antibacterial strategies need to be developed. Quorum sensing inhibitors represent a novel class of antibacterial compounds, which have the advantage of not interfering on bacterial growth, thereby without selective pressure that can lead to appearance of resistant strains. In this review, we discuss factors that regulate Stx production in EHEC as well as novel strategies to fight Stx and minimize development to HUS in EHEC-infected patients.

75 FR 51015 - Sorbitol From France: Notice of Rescission of Antidumping Duty Administrative Review

Science.gov (United States)

2010-08-18

... DEPARTMENT OF COMMERCE International Trade Administration [A-427-001] Sorbitol From France: Notice... order on sorbitol from France. The review covers one producer/exporter of sorbitol, Syral S.A.S. (Syral... Products International (CP), domestic producers of sorbitol, we are now rescinding this administrative...

75 FR 42380 - Revocation of Antidumping Duty Order on Sorbitol From France

Science.gov (United States)

2010-07-21

... Duty Order on Sorbitol From France AGENCY: Import Administration, International Trade Administration... sunset review of the antidumping duty order on sorbitol from France. See Initiation of Five-year... the existing antidumping duty order on sorbitol from France would not be likely to lead to...

Genome sequences of thirty Escherichia coli O157:H7 isolates recovered from a single dairy farm and its associated off-site heifer raising facility

Science.gov (United States)

Cattle are the primary reservoir of Escherichia coli O157:H7, the most frequently isolated serotype of enterohemorrhagic E. coli infections among humans in North America. To evaluate the diversity of E. coli O157:H7 isolates within a single dairy herd the genomes of 30 isolates collected over a 7-ye...

Comparative sequence analysis revealed altered chromosomal organization and a novel insertion sequence encoding DNA modification and potentially stress-related functions in an Escherichia coli O157:H7 foodborne isolate

Science.gov (United States)

We recently described the complete genome of enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain NADC 6564, an isolate of strain 86-24 linked to the 1986 disease outbreak. In the current study, we compared the chromosomal sequence of NADC 6564 to the well-characterized chromosomal sequences of ...

Synthesis of sorbitol by Zymomonas mobilis under high osmotic pressure Síntese de sorbitol por Zymomonas mobilis sob elevada pressão osmótica

Directory of Open Access Journals (Sweden)

Márcio de Barros

2006-09-01

Full Text Available The bacterium Zymomonas mobilis presents potential for sorbitol production when grown in culture medium with high sugar concentration. Sorbitol is produced and accumulated in the periplasma of the bacterium to protect the cells from the harmful effects of high osmotic pressure that results from the action of invertase on sucrose. The conversion of sucrose into glucose and fructose increases the osmolarity of the medium. However, an excessive increase in the osmotic pressure may decrease the sorbitol production. In this work Saccharomyces cerevisiae invertase was added two media containing sucrose 200 and 300 g.L-1. Sorbitol production in sucrose at 200 g.L-1 was 42.35 and 38.42 g.L-1, with and without the invertase treatment, respectively. In the culture medium with 300 g.L-1 sucrose, production reached 60.4 g.L-1 and with invertase treatment was 19.14 g.L-1. These results indicated that the excessive rise in osmotic pressure led to a significant decrease in sorbitol production by the Zymomonas mobilis bacterium in the sucrose medium treated with invertase.A bactéria Zymomonas mobilis, apresenta potencial para produção de sorbitol quando crescida em meio com alta concentração de açúcar. O sorbitol produzido é acumulado no periplasma da bactéria para conter os efeitos prejudiciais da elevada pressão osmótica, que resulta pela ação da enzima invertase, que promove hidrólise da sacarose. A conversão da sacarose em glicose e frutose aumentando a osmolaridade do meio. Entretanto, um aumento excessivo na pressão osmótica pode inibir a produção de sorbitol pela bactéria. Este trabalho empregou invertase de Saccharomyces cerevisiae nos meios de fermentação com sacarose a 200 e 300 g.L-1. A produção de sorbitol no meio com sacarose a 200 g.L-1 foi de 42,35 g.L-1 e 38,42 g.L-1 com e sem tratamento com invertase respectivamente. No meio com 300 g.L-1 sem tratamento, a produção foi de 60,42 e com tratamento 19,14 g.L-1. Estes

Towards a Molecular Definition of Enterohemorrhagic Escherichia coli (EHEC): Detection of Genes Located on O Island 57 as Markers To Distinguish EHEC from Closely Related Enteropathogenic E. coli Strains

Science.gov (United States)

Delannoy, Sabine; Beutin, Lothar

2013-01-01

Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains. PMID:23325824

PRODUKSI ANTIBIOTIKA OLEH Bacillus subtilis M10 DALAM MEDIA UREA-SORBITOL

Directory of Open Access Journals (Sweden)

Supartono Supartono

2012-04-01

Full Text Available PRODUCTION OF ANTIBIOTICS BY Bacillus subtilis M10 IN UREA-SORBITOL MEDIUM. Infection diseases still become the main health problems that suffered by people in Indonesia. Besides, there were many pathogen bacteria found to be resistant to the some antibiotics. Therefore, the efforts to get a new antibiotic require to be done continuously. A new local strain of Bacillus subtilis BAC4 has been known producing an antibiotic that inhibit Serratia marcescens ATCC 27117 growth. To make efficient the local strain, mutation on Bacillus subtilis BAC4 was done by using acridine orange and a mutant cell of Bacillus subtilis M10 that overproduction for producing antibiotic was obtained. Nevertheless, the production kinetics of antibiotic by this mutant has not been reported. The objective of this research was to study the production kinetics of antibiotic by Bacillus subtilis M10 mutant. The production of antibiotic was conducted using batch fermentation and antibiotic assay was performed with agar absorption method using Serratia marcescens ATCC 27117 as bacteria assay. Research result provided that Bacillus subtilis M10 mutant with overproduction of antibiotic produced an antibiotic since 8th hour’s fermentation and optimum of it production was at 14th hours after inoculation.  Penyakit infeksi masih menjadi masalah yang utama diderita oleh masyarakat Indonesia. Di samping itu, banyak bakteri patogen yang ditemukan resisten terhadap beberapa antibiotika. Oleh karena itu, upaya-upaya untuk mendapatkan antibiotika baru perlu dilakukan secara terus-menerus. Suatu galur lokal baru Bacillus subtilis BAC4 teridentifikasi memproduksi senyawa antibiotika yang menghambat pertumbuhan Serratia marcescens ATCC27117. Untuk memberdayakan galur tersebut, terhadap Bacillus subtilis BAC4 dilakukan mutasi dengan larutan akridin oranye dan diperoleh mutan Bacillus subtilis M10 yang memproduksi antibiotika berlebihan. Namun, kinetika produksi antibiotika oleh Bacillus

Discrimination of Enterohemorrhagic Escherichia coli (EHEC) from Non-EHEC Strains Based on Detection of Various Combinations of Type III Effector Genes

Science.gov (United States)

Delannoy, Sabine; Beutin, Lothar

2013-01-01

Enterohemorrhagic Escherichia coli (EHEC) strains comprise a subgroup of Shiga-toxin (Stx)-producing E. coli (STEC) and are characterized by a few serotypes. Among these, seven priority STEC serotypes (O26:H11, O45:H2, O103:H2, O111:H8, O121:H19, O145:H28, and O157:H7) are most frequently implicated in severe clinical illness worldwide. Currently, standard methods using stx, eae, and O-serogroup-specific gene sequences for detecting the top 7 EHEC serotypes bear the disadvantage that these genes can be found in non-EHEC strains as well. Here, we explored the suitability of ureD, espV, espK, espN, Z2098, and espM1 genes and combinations thereof as candidates for a more targeted EHEC screening assay. For a very large panel of E. coli strains (n = 1,100), which comprised EHEC (n = 340), enteropathogenic E. coli (EPEC) (n = 392), STEC (n = 193), and apathogenic strains (n = 175), we showed that these genetic markers were more prevalent in EHEC (67.1% to 92.4%) than in EPEC (13.3% to 45.2%), STEC (0.5% to 3.6%), and apathogenic E. coli strains (0 to 2.9%). It is noteworthy that 38.5% of the EPEC strains that tested positive for at least one of these genetic markers belonged to the top 7 EHEC serotypes, suggesting that such isolates might be Stx-negative derivatives of EHEC. The associations of espK with either espV, ureD, or Z2098 were the best combinations for more specific and sensitive detection of the top 7 EHEC strains, allowing detection of 99.3% to 100% of these strains. In addition, detection of 93.7% of the EHEC strains belonging to other serotypes than the top 7 offers a possibility for identifying new emerging EHEC strains. PMID:23884997

Characterization of antimicrobial activity in Kombucha fermentation

NARCIS (Netherlands)

Sreeramulu, G.; Zhu, Y.; Knol, W.

2001-01-01

Fermented tea drink, Kombucha, can inhibit the growth of Shigella sonnei, Escherichia coli, Salmonella enteritidis and Salmonella typhimurium. Several metabolites were analyzed every two days during a 14-day Kombucha fermentation. Levels of acetic acid and gluconic acid were found to increase with

Exposure to sorbitol during lactation causes metabolic alterations and genotoxic effects in rat offspring.

Science.gov (United States)

Cardoso, Felipe S; Araujo-Lima, Carlos F; Aiub, Claudia A F; Felzenszwalb, Israel

2016-10-17

Sorbitol is a polyol used by the food industry as a sweetener. Women are consuming diet and light products containing sorbitol during pregnancy and in the postnatal period to prevent themselves from excessive weight gain and maintain a slim body. Although there is no evidence for the genotoxicity of sorbitol in the perinatal period, this study focused on evaluating the effects of the maternal intake of sorbitol on the biochemical and toxicological parameters of lactating Wistar rat offspring after 14days of mother-to-offspring exposure. A dose-dependent reduction of offspring length was observed. An increase in sorbitol levels determined in the milk was also observed. However, we detected an inverse relationship between the exposition dose in milk fructose and triacylglycerols concentrations. There was an increase in the plasmatic levels of ALT, AST and LDLc and a decrease in proteins, cholesterol and glucose levels in the offspring. Sorbitol exposure caused hepatocyte genotoxicity, including micronuclei induction. Maternal sorbitol intake induced myelotoxicity and myelosuppression in their offspring. The Comet assay of the blood cells detected a dose-dependent genotoxic response within the sorbitol-exposed offspring. According to our results, sorbitol is able to induce important metabolic alterations and genotoxic responses in the exposed offspring. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Differentiation between Trichophyton mentagrophytes and T. rubrum by sorbitol assimilation.

OpenAIRE

Rezusta, A; Rubio, M C; Alejandre, M C

1991-01-01

Trichophyton rubrum was easily differentiated from T. mentagrophytes by its ability to assimilate sorbitol with an API 20C AUX strip. One hundred percent of 36 T. rubrum strains and none of 147 T. mentagrophytes strains assimilated sorbitol.

Molar concentrations of sorbitol and polyethylene glycol inhibit the Plasmodium aquaglyceroporin but not that of E. coli: involvement of the channel vestibules.

Science.gov (United States)

Song, Jie; Almasalmeh, Abdulnasser; Krenc, Dawid; Beitz, Eric

2012-05-01

The aquaglyceroporins of Escherichia coli, EcGlpF, and of Plasmodium falciparum, PfAQP, are probably the best characterized members of the solute-conducting aquaporin (AQP) subfamily. Their crystal structures have been elucidated and numerous experimental and theoretical analyses have been conducted. However, opposing reports on their rates of water permeability require clarification. Hence, we expressed EcGlpF and PfAQP in yeast, prepared protoplasts, and compared water and glycerol permeability of both aquaglyceroporins in the presence of different osmolytes, i.e. sucrose, sorbitol, PEG300, and glycerol. We found that water permeability of PfAQP strongly depends on the external osmolyte, with full inhibition by sorbitol, and increasing water permeability when glycerol, PEG300, and sucrose were used. EcGlpF expression did not enhance water permeability over that of non-expressing control protoplasts regardless of the osmolyte. Glycerol permeability of PfAQP was also inhibited by sorbitol, but to a smaller extent, whereas EcGlpF conducted glycerol independently of the osmolyte. Mixtures of glycerol and urea passed PfAQP equally well under isosmotic conditions, whereas under hypertonic conditions in a countercurrent with water, glycerol was clearly preferred over urea. We conclude that PfAQP has high and EcGlpF low water permeability, and explain the inhibiting effect of sorbitol on PfAQP by its binding to the extracellular vestibule. The preference for glycerol under hypertonic conditions implies that in a physiological setting, PfAQP mainly acts as a water/glycerol channel rather than a urea facilitator. Copyright © 2012 Elsevier B.V. All rights reserved.

Stepwise metabolic engineering of Gluconobacter oxydans WSH-003 for the direct production of 2-keto-L-gulonic acid from D-sorbitol.

Science.gov (United States)

Gao, Lili; Hu, Yudong; Liu, Jie; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2014-07-01

2-Keto-L-gulonic acid (2-KLG), the direct precursor of vitamin C, is currently produced by a two-step fermentation route from D-sorbitol. However, this route involves three bacteria, making the mix-culture system complicated and redundant. Thus, replacement of the conventional two-step fermentation process with a one-step process could be revolutionary in vitamin C industry. In this study, different combinations of five L-sorbose dehydrogenases (SDH) and two L-sorbosone dehydrogenases (SNDH) from Ketogulonicigenium vulgare WSH-001 were introduced into Gluconobacter oxydans WSH-003, an industrial strain used for the conversion of d-sorbitol to L-sorbose. The optimum combination produced 4.9g/L of 2-KLG. In addition, 10 different linker peptides were used for the fusion expression of SDH and SNDH in G. oxydans. The best recombinant strain (G. oxydans/pGUC-k0203-GS-k0095) produced 32.4g/L of 2-KLG after 168h. Furthermore, biosynthesis of pyrroloquinoline quinine (PQQ), a cofactor of those dehydrogenases, was enhanced to improve 2-KLG production. With the stepwise metabolic engineering of G. oxydans, the final 2-KLG production was improved to 39.2g/L, which was 8.0-fold higher than that obtained using independent expression of the dehydrogenases. These results bring us closer to the final one-step industrial-scale production of vitamin C. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Humectancies of d-tagatose and d-sorbitol.

Science.gov (United States)

Lu, Y

2001-06-01

Most toothpastes contain either d-sorbitol or glycerin, or both, as humectants. Both compounds are about half as sweet as sucrose. This level of sweetness is not as intense as desired by most people when brushing teeth. Therefore, many brands of toothpaste add saccharin, a high-intensity sweetener, to increase product sweetness to acceptable levels. While this combination provides the required bulk, humectancy and sweetness, the last characteristic suffers from the widely perceived metallic, or bitter, aftertaste of saccharin. d-tagatose, a full-bulk, low-calorie, sucrose-like sweetener with about twice the sweetness of d-sorbitol, and which does not promote tooth decay, holds promise as a sole sweetener for toothpastes. The only untested aspect of this use of d-tagatose was its humectancy, the characteristic that retains the required level of moisture in toothpaste. The current study was made to investigate this important property, to make a direct comparison of the humectancies of d-tagatose and d-sorbitol as pure substances, and to determine whether the humectancy of d-tagatose is sufficient to counter the crystallizing potentiation of the abrasives used in toothpastes. The humectancies of d-tagatose and d-sorbitol were tested through measuring their water activity (a(w)) vs. water content. By comparing their desorption curves, d-tagatose was seen to have a humectancy equal to that of d-sorbitol when a(w) in the d-tagatose solution was above 0.62. d-Tagatose was then tested in toothpastes containing typical abrasives to determine whether the abrasives would induce crystallization of the sweetener. The addition of 20-25% wt/wt of d-tagatose to the Tom of Maine's toothpastes imparted a satisfactory sweetness. It was found that, within that range of concentration, d-tagatose retained its humectancy, and did not crystallize in the popular brands of commercial toothpastes tested. Thus, d-tagatose could be used as a humectant sweetener in toothpastes, although further

Vaccination with DNA encoding truncated enterohemorrhagic Escherichia coli (EHEC factor for adherence-1 gene (efa-1’ confers protective immunity to mice infected with E. coli O157:H7

Directory of Open Access Journals (Sweden)

Roberto eRiquelme-Neira

2016-01-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC O157:H7 is the predominant causative agent of hemorrhagic colitis in humans and is the cause of haemolytic uraemic syndrome and other illnesses. Cattle have been implicated as the main reservoir of this organism. Here, we evaluated the immunogenicity and protective efficacy of a DNA vaccine encoding conserved sequences of truncated EHEC factor for adherence-1 (efa-1’ in a mouse model. Intranasal administration of plasmid DNA carrying the efa-1’ gene (pVAXefa-1’ into C57BL/6 mice elicited both humoral and cellular immune responses. In animals immunized with pVAXefa-1`, EHEC-secreted protein-specific IgM and IgG antibodies were detected in sera at day 45. Anti-EHEC-secreted protein sIgA was also detected in nasal and bronchoalveolar lavages. In addition, antigen-specific T-cell-proliferation, IL-10 and IFN-γ were observed upon re-stimulation with either heat-killed bacteria or EHEC-secreted proteins. Vaccinated animals were also protected against challenge with E. coli O157:H7 strain EDL933. These results suggest that DNA vaccine encoding efa-1´ have therapeutic potential in interventions against EHEC infections. This approach could lead to a new strategy in the production of vaccines that prevent infections in cattle.

40 CFR 180.1262 - Sorbitol octanoate; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Sorbitol octanoate; exemption from the... Exemptions From Tolerances § 180.1262 Sorbitol octanoate; exemption from the requirement of a tolerance. An exemption from the requirement of a tolerance is established for residues of sorbitol octanoate in or on all...

Scale-up from microtiter plate to laboratory fermenter: evaluation by online monitoring techniques of growth and protein expression in Escherichia coli and Hansenula polymorpha fermentations

Directory of Open Access Journals (Sweden)

Engelbrecht Christoph

2009-12-01

Full Text Available Abstract Background In the past decade, an enormous number of new bioprocesses have evolved in the biotechnology industry. These bioprocesses have to be developed fast and at a maximum productivity. Up to now, only few microbioreactors were developed to fulfill these demands and to facilitate sample processing. One predominant reaction platform is the shaken microtiter plate (MTP, which provides high-throughput at minimal expenses in time, money and work effort. By taking advantage of this simple and efficient microbioreactor array, a new online monitoring technique for biomass and fluorescence, called BioLector, has been recently developed. The combination of high-throughput and high information content makes the BioLector a very powerful tool in bioprocess development. Nevertheless, the scalabilty of results from the micro-scale to laboratory or even larger scales is very important for short development times. Therefore, engineering parameters regarding the reactor design and its operation conditions play an important role even on a micro-scale. In order to evaluate the scale-up from a microtiter plate scale (200 μL to a stirred tank fermenter scale (1.4 L, two standard microbial expression systems, Escherichia coli and Hansenula polymorpha, were fermented in parallel at both scales and compared with regard to the biomass and protein formation. Results Volumetric mass transfer coefficients (kLa ranging from 100 to 350 1/h were obtained in 96-well microtiter plates. Even with a suboptimal mass transfer condition in the microtiter plate compared to the stirred tank fermenter (kLa = 370-600 1/h, identical growth and protein expression kinetics were attained in bacteria and yeast fermentations. The bioprocess kinetics were evaluated by optical online measurements of biomass and protein concentrations exhibiting the same fermentation times and maximum signal deviations below 10% between the scales. In the experiments, the widely applied green

Kinetic Modeling of Ethanol Batch Fermentation by Escherichia Coli FBWHR Using Hot-Water Sugar Maple Wood Extract Hydrolyzate as Substrate

Directory of Open Access Journals (Sweden)

Yang Wang

2014-12-01

Full Text Available A recombinant strain of Escherichia coli FBWHR was used for ethanol fermentation from hot-water sugar maple wood extract hydrolyzate in batch experiments. Kinetic studies of cell growth, sugar utilization and ethanol production were investigated at different initial total sugar concentrations of wood extract hydrolyzate. The highest ethanol concentration of 24.05 g/L was obtained using an initial total sugar concentration of 70.30 g/L. Unstructured models were developed to describe cell growth, sugar utilization and ethanol production and validated by comparing the predictions of model and experimental data. The results from this study could be expected to provide insights into the process performance, optimize the process and aid in the design of processes for large-scale production of ethanol fermentation from woody biomass.

Production of sorbitol and ethanol from Jerusalem artichokes by Saccharomyces cerevisiae ATCC 36859

Energy Technology Data Exchange (ETDEWEB)

Duvnjak, Z.; Duan, Z.D. (Ottawa Univ., ON (Canada). Dept. of Chemical Engineering); Turcotte, G. (Acadia Univ., Wolfville, NS (Canada). Dept. of Food Science)

1991-09-01

This study shows the possible use of Jerusalem artichokes for the production of sorbitol and ethanol by Saccharomyces cerevisiae ATCC 36859. Ethanol was produced from the beginning of the process, while sorbitol production started after glucose had been entirely consumed from Jerusalem artichoke (J.a.) juice. The importance of yeast extract and inoculum concentrations on the production of sorbitol from the above raw material was demonstrated. With a low initial biomass concentration sorbitol was not produced in pure J.a. juice. When the juice was supplemented with 3% yeast extract, the concentration of sorbitol was 4.6%. The sorbitol, ethanol and biomass yields (gram of product produced per gram of sugars consumed) were 0.259, 0.160 and 0.071 at the end of the process respectively. Adding glucose to increase its concentration to about 9% in the J.a. juice with 3% yeast extract had a positive effect on the production of ethanol, while commencement of the production of sorbitol was delayed and its final concentration was less than 50% of its concentration in the medium without added glucose. The effect of glucose was much stronger when it was added during the process than when added at the beginning of the process. (orig.).

Colon Necrosis Due to Sodium Polystyrene Sulfonate with and without Sorbitol: An Experimental Study in Rats.

Science.gov (United States)

Ayoub, Isabelle; Oh, Man S; Gupta, Raavi; McFarlane, Michael; Babinska, Anna; Salifu, Moro O

2015-01-01

Based on a single rat study by Lillemoe et al, the consensus has been formed to implicate sorbitol rather than sodium polystyrene sulfonate (SPS) as the culprit for colon necrosis in humans treated with SPS and sorbitol. We tested the hypothesis that colon necrosis by sorbitol in the experiment was due to the high osmolality and volume of sorbitol rather than its chemical nature. 26 rats underwent 5/6 nephrectomy. They were divided into 6 groups and given enema solutions under anesthesia (normal saline, 33% sorbitol, 33% mannitol, SPS in 33% sorbitol, SPS in normal saline, and SPS in distilled water). They were sacrificed after 48 hours of enema administration or earlier if they were very sick. The gross appearance of the colon was visually inspected, and then sliced colon tissues were examined under light microscopy. 1 rat from the sorbitol and 1 from the mannitol group had foci of ischemic colonic changes. The rats receiving SPS enema, in sorbitol, normal saline, distilled water, had crystal deposition with colonic necrosis and mucosal erosion. All the rats not given SPS survived until sacrificed at 48 h whereas 11 of 13 rats that received SPS in sorbitol, normal saline or distilled water died or were clearly dying and sacrificed sooner. There was no difference between sorbitol and mannitol when given without SPS. In a surgical uremic rat model, SPS enema given alone or with sorbitol or mannitol seemed to cause colon necrosis and high mortality rate, whereas 33% sorbitol without SPS did not.

Detection of Enterohemorrhagic Escherichia coli Related Genes in E. coli Strains Belonging to B2 Phylogroup Isolated from Urinary Tract Infections in Combination with Antimicrobial Resistance Phenotypes

Directory of Open Access Journals (Sweden)

Hamid Staji

2017-07-01

Full Text Available Background:  This study was conducted to detect the prevalence of EHEC virulence genes and antimicrobial resistance profile of Escherichia coli strains belonging to B2 phylogroup implicated in Urinary tract infections in Semnan, Iran.Methods:   From 240 urine samples 160 E. coli strains were isolated, biochemically. Then, E. coli isolates were examined by Multiplex-PCR for phylogenetic typing and detection of virulence genes (hly, stx1, stx2, eae associated with Enterohemorrhagic E. coli. Finally, Antimicrobial resistance of E. coli isolates were characterized using Disk Diffusion method.  Results:  From 160 E. coli isolates, 75 strains (47% were assigned to B2 phylogenetic group and prevalence of virulence genes were as follow: hly (21.3%, stx1 (16%, stx2 (10.6% and eae (6.7%, subsequently.  Phenotypic antimicrobial resistance of B2 isolates showed that all isolates were sensitive to Meropenem and Furazolidone and then highest frequency of resistance was observed to Streptomycin, Oxytetracycline, Neomycin, Nalidixic acid and Ampicillin (98.7% to 49.3%. Also low resistance prevalence was observed in case of Ceftizoxime, Lincospectin, Imipenem, Chloramphenicol and flurefenicole (16% to 1.3%.Conclusion:   The data suggest a high prevalence of antibiotic resistance in UPEC strains belonging to B2 phylogroup even for the antimicrobials using in pet and farm animals and their potential to cause EHEC specific clinical symptoms which may represent a serious health risk since these strains can be transmitted to GI tract and act as a reservoir for other uropathogenic E. coli and commensal strains.

Theoretical investigation of interaction of sorbitol molecules with alcohol dehydrogenase in aqueous solution using molecular dynamics simulation.

Science.gov (United States)

Bahrami, Homayoon; Zahedi, Mansour; Moosavi-Movahedi, Ali Akbar; Azizian, Homa; Amanlou, Massoud

2011-03-01

The nature of protein-sorbitol-water interaction in solution at the molecular level, has been investigated using molecular dynamics simulations. In order to do this task, two molecular dynamics simulations of the protein ADH in solution at room temperature have been carried out, one in the presence (about 0.9 M) and another in the absence of sorbitol. The results show that the sorbitol molecules cluster and move toward the protein, and form hydrogen bonds with protein. Also, coating by sorbitol reduces the conformational fluctuations of the protein compared to the sorbitol-free system. Thus, it is concluded that at moderate concentration of sorbitol solution, sorbitol molecules interact with ADH via many H-bonds that prevent the protein folding. In fact, at more concentrated sorbitol solution, water and sorbitol molecules accumulate around the protein surface and form a continuous space-filling network to reduce the protein flexibility. Namely, in such solution, sorbitol molecules can stabilize a misfolded state of ADH, and prevent the protein from folding to its native structure.

Skeletal Muscle Sorbitol Levels in Diabetic Rats with and without Insulin Therapy and Endurance Exercise Training

Science.gov (United States)

Sánchez, O. A.; Walseth, T. F.; Snow, L. M.; Serfass, R. C.; Thompson, L. V.

2009-01-01

Sorbitol accumulation is postulated to play a role in skeletal muscle dysfunction associated with diabetes. The purpose of this study was to determine the effects of insulin and of endurance exercise on skeletal muscle sorbitol levels in streptozotocin-induced diabetic rats. Rats were assigned to one experimental group (control sedentary, control exercise, diabetic sedentary, diabetic exercise, diabetic sedentary no-insulin). Diabetic rats received daily subcutaneous insulin. The exercise-trained rats ran on a treadmill (1 hour, 5X/wk, for 12 weeks). Skeletal muscle sorbitol levels were the highest in the diabetic sedentary no-insulin group. Diabetic sedentary rats receiving insulin had similar sorbitol levels to control sedentary rats. Endurance exercise did not significantly affect sorbitol levels. These results indicate that insulin treatment lowers sorbitol in skeletal muscle; therefore sorbitol accumulation is probably not related to muscle dysfunction in insulin-treated diabetic individuals. Endurance exercise did not influence intramuscular sorbitol values as strongly as insulin. PMID:20016800

Chromatin-associated regulation of sorbitol synthesis in flower buds of peach.

Science.gov (United States)

Lloret, Alba; Martínez-Fuentes, Amparo; Agustí, Manuel; Badenes, María Luisa; Ríos, Gabino

2017-11-01

PpeS6PDH gene is postulated to mediate sorbitol synthesis in flower buds of peach concomitantly with specific chromatin modifications. Perennial plants have evolved an adaptive mechanism involving protection of meristems within specialized structures named buds in order to survive low temperatures and water deprivation during winter. A seasonal period of dormancy further improves tolerance of buds to environmental stresses through specific mechanisms poorly known at the molecular level. We have shown that peach PpeS6PDH gene is down-regulated in flower buds after dormancy release, concomitantly with changes in the methylation level at specific lysine residues of histone H3 (H3K27 and H3K4) in the chromatin around the translation start site of the gene. PpeS6PDH encodes a NADPH-dependent sorbitol-6-phosphate dehydrogenase, the key enzyme for biosynthesis of sorbitol. Consistently, sorbitol accumulates in dormant buds showing higher PpeS6PDH expression. Moreover, PpeS6PDH gene expression is affected by cold and water deficit stress. Particularly, its expression is up-regulated by low temperature in buds and leaves, whereas desiccation treatment induces PpeS6PDH in buds and represses the gene in leaves. These data reveal the concurrent participation of chromatin modification mechanisms, transcriptional regulation of PpeS6PDH and sorbitol accumulation in flower buds of peach. In addition to its role as a major translocatable photosynthate in Rosaceae species, sorbitol is a widespread compatible solute and cryoprotectant, which suggests its participation in tolerance to environmental stresses in flower buds of peach.

Fatal case of hemolytic-uremic syndrome in an adult due to a rare serogroup O91 Entero hemorrhagic Escherichia coli associated with a Clostridium difficile infection. More than meets the eye

Directory of Open Access Journals (Sweden)

Thomas Guillard

2015-08-01

Full Text Available Hemolytic-uremic syndrome due to enterohemorrhagic Escherichia coli, belonging to serogroup O91 has rarely been described. We report here a case of post-diarrheal HUS due to EHEC O91 in an elderly patient for whom diagnosis was delayed given a previously diagnosed C. difficile infection. This case highlights the usefulness of Shiga-toxin detection.

Trehalose 6-phosphate signal is closely related to sorbitol in apple (Malus domestica Borkh. cv. Gala

Directory of Open Access Journals (Sweden)

Wen Zhang

2017-02-01

Full Text Available Trehalose-6-phosphate (Tre6P is a precursor of trehalose, which is widespread in nature and greatly influences plant growth and development. Tre6P acts as a signal of carbon availability in many plants, but little is known about the function of Tre6P in rosaceous plants, which have specific sorbitol biosynthesis and transportation pathways. In the present study, Tre6P levels and Sorbitol:Tre6P ratios were analyzed in apple (Malus domestica, Borkh. cv. Gala. Tre6P levels were positively correlated with sorbitol content but negatively correlated with sucrose, glucose, and fructose content in developing fruit. However, under sorbitol-limited conditions, Tre6P levels were positively correlated with both sorbitol and sucrose. In the presence of different exogenous sugar supply, Tre6P levels increased corresponding with sorbitol, but this was not the case with sucrose. In addition, Tre6P content and sorbitol:Tre6P ratios were more highly correlated with ADP-glucose levels under sorbitol-limited conditions and fruit development stages, respectively. These results suggest that Tre6P is more closely related to sorbitol than other soluble sugars and has an important role in influencing carbon metabolism in apple.

Trehalose 6-phosphate signal is closely related to sorbitol in apple (Malus domestica Borkh. cv. Gala)

Science.gov (United States)

Zhang, Wen; Lunn, John E.; Feil, Regina; Wang, Yufei; Zhao, Jingjing; Tao, Hongxia; Zhao, Zhengyang

2017-01-01

ABSTRACT Trehalose-6-phosphate (Tre6P) is a precursor of trehalose, which is widespread in nature and greatly influences plant growth and development. Tre6P acts as a signal of carbon availability in many plants, but little is known about the function of Tre6P in rosaceous plants, which have specific sorbitol biosynthesis and transportation pathways. In the present study, Tre6P levels and Sorbitol:Tre6P ratios were analyzed in apple (Malus domestica, Borkh. cv. Gala). Tre6P levels were positively correlated with sorbitol content but negatively correlated with sucrose, glucose, and fructose content in developing fruit. However, under sorbitol-limited conditions, Tre6P levels were positively correlated with both sorbitol and sucrose. In the presence of different exogenous sugar supply, Tre6P levels increased corresponding with sorbitol, but this was not the case with sucrose. In addition, Tre6P content and sorbitol:Tre6P ratios were more highly correlated with ADP-glucose levels under sorbitol-limited conditions and fruit development stages, respectively. These results suggest that Tre6P is more closely related to sorbitol than other soluble sugars and has an important role in influencing carbon metabolism in apple. PMID:28069587

Enhanced porcine circovirus Cap protein production by Pichia pastoris with a fuzzy logic DO control based methanol/sorbitol co-feeding induction strategy.

Science.gov (United States)

Ding, Jian; Zhang, Chunling; Gao, Minjie; Hou, Guoli; Liang, Kexue; Li, Chunhua; Ni, Jianping; Li, Zhen; Shi, Zhongping

2014-05-10

Porcine circovirus Cap protein production by P. pastoris with strong AOX promoter suffered with the problems with traditional pure methanol induction: (1) inefficient methanol metabolism; (2) extensive oxygen supply load; (3) difficulty in stable DO control; (4) low protein titer. In this study, based on the difference of DO change patterns in response to methanol and sorbitol additions, a novel fuzzy control system was proposed to automatically regulate the co-feeding rates of methanol and sorbitol for efficient Cap protein induction. With aid of the proposed control system when setting DO control level at 10%, overall fermentation performance was significantly improved: (1) DO could be stably controlled under mild aeration condition; (2) methanol consumption rate could be restricted at moderate level and the major enzymes involved with methanol metabolism were largely activated; (3) Cap protein concentration reached a highest level of 198mg/L, which was about 64% increase over the best one using the pure methanol induction strategies. Copyright © 2014 Elsevier B.V. All rights reserved.

MATHEMATICAL MODELING, AUTOMATION AND CONTROL OF THE BIOCONVERSION OF SORBITOL TO SORBOSE IN THE VITAMIN C PRODUCTION PROCESS I. MATHEMATICAL MODELING

Directory of Open Access Journals (Sweden)

A. Bonomi

1997-12-01

Full Text Available In 1990, the Biotechnology and the Control Systems Groups of IPT started developing a system for the control and automation of fermentation processes, applied to the oxidation of sorbitol to sorbose by the bacteria Gluconobacter oxydans, the microbial step of the vitamin C production process, that was chosen as a case study. Initially, a thirteen-parameter model was fitted to represent the batch operation of the system utilizing a nonlinear regression analysis, the flexible polyhedron method. Based on these results, a model for the continuous process (with the same kinetic equations was constructed and its optimum operating point obtained

Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

OpenAIRE

Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

2012-01-01

Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-St...

Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

OpenAIRE

Yanil R Parma; Pablo A Chacana; Paula María Alejandra Lucchesi; Ariel eRoge; Claudia V Granobles Velandia; Alejandra eKrüger; Alejandra eKrüger; Alberto E. Parma; Mariano Enrique Fernandez Miyakawa

2012-01-01

Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-St...

Strand-specific transcriptomes of Enterohemorrhagic Escherichia coli in response to interactions with ground beef microbiota: interactions between microorganisms in raw meat.

Science.gov (United States)

Galia, Wessam; Leriche, Francoise; Cruveiller, Stéphane; Garnier, Cindy; Navratil, Vincent; Dubost, Audrey; Blanquet-Diot, Stéphanie; Thevenot-Sergentet, Delphine

2017-08-03

Enterohemorrhagic Escherichia coli (EHEC) are zoonotic agents associated with outbreaks worldwide. Growth of EHEC strains in ground beef could be inhibited by background microbiota that is present initially at levels greater than that of the pathogen E. coli. However, how the microbiota outcompetes the pathogenic bacteria is unknown. Our objective was to identify metabolic pathways of EHEC that were altered by natural microbiota in order to improve our understanding of the mechanisms controlling the growth and survival of EHECs in ground beef. Based on 16S metagenomics analysis, we identified the microbial community structure in our beef samples which was an essential preliminary for subtractively analyzing the gene expression of the EHEC strains. Then, we applied strand-specific RNA-seq to investigate the effects of this microbiota on the global gene expression of EHEC O26 21765 and O157 EDL933 strains by comparison with their behavior in beef meat without microbiota. In strain O26 21765 , the expression of genes connected with nitrate metabolism and nitrite detoxification, DNA repair, iron and nickel acquisition and carbohydrate metabolism, and numerous genes involved in amino acid metabolism were down-regulated. Further, the observed repression of ftsL and murF, involved respectively in building the cytokinetic ring apparatus and in synthesizing the cytoplasmic precursor of cell wall peptidoglycan, might help to explain the microbiota's inhibitory effect on EHECs. For strain O157 EDL933 , the induced expression of the genes implicated in detoxification and the general stress response and the repressed expression of the peR gene, a gene negatively associated with the virulence phenotype, might be linked to the survival and virulence of O157:H7 in ground beef with microbiota. In the present study, we show how RNA-Seq coupled with a 16S metagenomics analysis can be used to identify the effects of a complex microbial community on relevant functions of an individual

Predicting the concentration of verotoxin-producing Escherichia coli bacteria during processing and storage of fermented raw-meat sausages.

Science.gov (United States)

Quinto, E J; Arinder, P; Axelsson, L; Heir, E; Holck, A; Lindqvist, R; Lindblad, M; Andreou, P; Lauzon, H L; Marteinsson, V Þ; Pin, C

2014-05-01

A model to predict the population density of verotoxigenic Escherichia coli (VTEC) throughout the elaboration and storage of fermented raw-meat sausages (FRMS) was developed. Probabilistic and kinetic measurement data sets collected from publicly available resources were completed with new measurements when required and used to quantify the dependence of VTEC growth and inactivation on the temperature, pH, water activity (aw), and concentration of lactic acid. Predictions were compared with observations in VTEC-contaminated FRMS manufactured in a pilot plant. Slight differences in the reduction of VTEC were predicted according to the fermentation temperature, 24 or 34°C, with greater inactivation at the highest temperature. The greatest reduction was observed during storage at high temperatures. A population decrease greater than 6 decimal logarithmic units was observed after 66 days of storage at 25°C, while a reduction of only ca. 1 logarithmic unit was detected at 12°C. The performance of our model and other modeling approaches was evaluated throughout the processing of dry and semidry FRMS. The greatest inactivation of VTEC was predicted in dry FRMS with long drying periods, while the smallest reduction was predicted in semidry FMRS with short drying periods. The model is implemented in a computing tool, E. coli SafeFerment (EcSF), freely available from http://www.ifr.ac.uk/safety/EcoliSafeFerment. EcSF integrates growth, probability of growth, and thermal and nonthermal inactivation models to predict the VTEC concentration throughout FRMS manufacturing and storage under constant or fluctuating environmental conditions.

Feedlot- and Pen-Level Prevalence of Enterohemorrhagic Escherichia coli in Feces of Commercial Feedlot Cattle in Two Major U.S. Cattle Feeding Areas.

Science.gov (United States)

Cull, Charley A; Renter, David G; Dewsbury, Diana M; Noll, Lance W; Shridhar, Pragathi B; Ives, Samuel E; Nagaraja, Tiruvoor G; Cernicchiaro, Natalia

2017-06-01

The objective of this study was to determine feedlot- and pen-level fecal prevalence of seven enterohemorrhagic Escherichia coli (EHEC) belonging to serogroups (O26, O45, O103, O111, O121, O145, and O157, or EHEC-7) in feces of feedlot cattle in two feeding areas in the United States. Cattle pens from four commercial feedlots in each of the two major U.S. beef cattle areas were sampled. Up to 16 pen-floor fecal samples were collected from each of 4-6 pens per feedlot, monthly, for a total of three visits per feedlot, from June to August, 2014. Culture procedures including fecal enrichment in E. coli broth, immunomagnetic separation, and plating on selective media, followed by confirmation through polymerase chain reaction (PCR) testing, were conducted. Generalized linear mixed models were fitted to estimate feedlot-, pen-, and sample-level fecal prevalence of EHEC-7 and to evaluate associations between potential demographic and management risk factors with feedlot and within-pen prevalence of EHEC-7. All study feedlots and 31.0% of the study pens had at least one non-O157 EHEC-positive fecal sample, whereas 62.4% of pens tested positive for EHEC O157; sample-level prevalence estimates ranged from 0.0% for EHEC O121 to 18.7% for EHEC O157. Within-pen prevalence of EHEC O157 varied significantly by sampling month; similarly within-pen prevalence of non-O157 EHEC varied significantly by month and by the sex composition of the pen (heifer, steer, or mixed). Feedlot management factors, however, were not significantly associated with fecal prevalence of EHEC-7. Intraclass correlation coefficients for EHEC-7 models indicated that most of the variation occurred between pens, rather than within pens, or between feedlots. Hence, the potential combination of preharvest interventions and pen-level management strategies may have positive food safety impacts downstream along the beef chain.

The two-component system CpxRA negatively regulates the Locus of Enterocyte Effacement of enterohemorrhagic Escherichia coli involving sigma 32 and Lon protease

Directory of Open Access Journals (Sweden)

MIGUEL A. eDE LA CRUZ

2016-02-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC is a significant cause of serious human gastrointestinal disease worldwide. EHEC strains contain a pathogenicity island called the locus of enterocyte effacement (LEE, which encodes virulence factors responsible for damaging the gut mucosa. The Cpx envelope stress response of E. coli is controlled by a two-component system consisting of a sensor histidine kinase (CpxA and a cytoplasmic response regulator (CpxR. In this study, we investigated the role of CpxRA in the expression of LEE-encoded virulence factors of EHEC. We found that a mutation in cpxA significantly affected adherence of EHEC to human epithelial cells. Analysis of this mutant revealed the presence of high levels of CpxR which repressed transcription of grlA and ler, the main positive virulence regulators of the LEE, and influenced negatively the production of the type 3 secretion system–associated EspABD translocator proteins. It is known that CpxR activates rpoH (Sigma factor 32, which in turns activates transcription of the lon protease gene. We found that transcription levels of ler and grlA were significantly increased in the lon and cpxA lon mutants suggesting that lon is involved in down-regulating LEE genes. In addition, the Galleria mellonella model of infection was used to analyze the effect of the loss of the cpx and lon genes in EHEC’s ability to kill the larvae. We found that the cpxA mutant was significantly deficient at killing the larvae however, the cpxA lon mutant which overexpresses LEE genes in vitro, was unable to kill the larvae, suggesting that virulence in the G. mellonella model is T3SS independent and that CpxA modulates virulence through a yet unknown EHEC-specific factor. Our data provides new insights and broadens our scope into the complex regulatory network of the LEE in which the CpxA sensor kinase plays an important role in a cascade involving both global and virulence regulators.

Ethanol fermentation by immobilized cells of Zymomonas mobilis

Energy Technology Data Exchange (ETDEWEB)

Grote, W.

1985-01-01

Previous studies have shown that immobilized yeast cell cultures have commercial potential for fuel ethanol production. In this study the suitability of strains of Z. mobilis for whole cell immobilization was investigated. Experiments revealed that immobilization in Ca-alginate or K-carrageenan gel or use of flocculating strains was effective for ethanol production at relatively high productivities. Two laboratory size reactors were designed and constructed. These were a compartmented multiple discshaft column and a tower fermentor. Results of this work supported other studies that established that growth and fermentation could be uncoupled. The data indicated that specific metabolic rates were dependent on the nature of the fermentation media. The addition of lactobacilli to Z. mobilis continuous fermentations had only a transient effect, and was unlikely to affect an immobilized Z. mobilis process. With 150 gl/sup -1/ glucose media and a Z. mobilis ZM4 immobilized cell reactor, a maximum volumetric ethanol productivity of 55 gl/sup -1/h/sup -1/ was obtained. The fermentation of sucrose media or sucrose-based raw materials (molasses, cane juice, synthetic mill liquor) by immobilized Z. mobilis ZM4 revealed a pattern of rapid sucrose hydrolysis, preferential glucose utilization and the conversion of fructose to the undesirable by-products levan and sorbitol.

Caloric utilization of sorbitol and isomalt in the rat

International Nuclear Information System (INIS)

Figdor, S.K.; Allingham, R.P.; Kita, D.A.; Hobbs, D.C.

1987-01-01

Sorbitol and isomalt are modified saccharides used to substitute for the physical properties of sucrose in various prepared foods. The merits of the various methods for determining caloric availability were reviewed. Balance and growth curve methods are inaccurate and inappropriate for determination of the caloric availability of these substances when present in diets at low concentrations, whereas the radiolabel disposition method is a direct and precise measure of utilization. Accordingly, the authors administered uniformly 14 C-labeled material to rats and collected excreta and expired air. The appearance of about half of the label in CO 2 indicated that, by comparison with labeled glucose, about 80% of the orally administered sorbitol and isomalt was calorically available to the rat. The high caloric availabilities of these materials were confirmed by the appearance in feces of only 14 and 12% of the administered label from sorbitol and isomalt, respectively

Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion.

Science.gov (United States)

Arroyo-López, Francisco N; Blanquet-Diot, Stéphanie; Denis, Sylvain; Thévenot, Jonathan; Chalancon, Sandrine; Alric, Monique; Rodríguez-Gómez, Francisco; Romero-Gil, Verónica; Jiménez-Díaz, Rufino; Garrido-Fernández, Antonio

2014-01-01

The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933) and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, L. pentosus TOMC-LAB2, and L. pentosus TOMC-LAB4) during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum) resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens.

Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion

Directory of Open Access Journals (Sweden)

Francisco Noé eArroyo López

2014-10-01

Full Text Available The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933 and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, Lactobacillus pentosus TOMC-LAB2 and Lactobacillus pentosus TOMC-LAB4 during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens.

Molecular evidence of sorbitol dehydrogenase in tomato, a non-Rosaceae plant.

Science.gov (United States)

Ohta, Kazuhiro; Moriguchi, Ryo; Kanahama, Koki; Yamaki, Shohei; Kanayama, Yoshinori

2005-12-01

The enzyme NAD-dependent sorbitol dehydrogenase (SDH) is well characterized in the Rosaceae family of fruit trees, which synthesizes sorbitol as a translocatable photosynthate. Expressed sequence tags of SDH-like sequences have also been generated from various non-Rosaceae species that do not synthesize sorbitol as a primary photosynthetic product, but the physiological roles of the encoded proteins in non-Rosaceae plants are unknown. Therefore, we isolated an SDH-like cDNA (SDL) from tomato (Lycopersicon esculentum Mill.). Genomic Southern blot analysis suggested that SDL exists in the tomato genome as a single-copy gene. Northern blot analysis showed that SDL is ubiquitously expressed in tomato plants. Recombinant SDL protein was produced and purified for enzymatic characterization. SDL catalyzed the interconversion of sorbitol and fructose with NAD (H). SDL showed highest activity for sorbitol among the several substrates tested. SDL showed no activity with NADP+. Thus, SDL was identified as a SDH, although the Km values and substrate specificity of SDL were significantly different from those of SDH purified from the Japanese pear (Pyrus pyrifolia), a Rosaceae fruit tree. In addition, tomato was transformed with antisense SDL to evaluate the contribution of SDL to SDH activity in tomato. The transformation decreased SDH activity to approximately 50% on average. Taken together, these results provide molecular evidence of SDH in tomato, and SDL was renamed LeSDH.

Modulation of δ-Aminolevulinic Acid Dehydratase Activity by the Sorbitol-Induced Osmotic Stress in Maize Leaf Segments.

Science.gov (United States)

Jain, M; Tiwary, S; Gadre, R

2018-01-01

Osmotic stress induced with 1 M sorbitol inhibited δ-aminolevulinic acid dehydratase (ALAD) and aminolevulinic acid (ALA) synthesizing activities in etiolated maize leaf segments during greening; the ALAD activity was inhibited to a greater extent than the ALA synthesis. When the leaves were exposed to light, the ALAD activity increased for the first 8 h, followed by a decrease observed at 16 and 24 h in both sorbitol-treated and untreated leaf tissues. The maximum inhibition of the enzyme activity was observed in the leaf segments incubated with sorbitol for 4 to 8 h. Glutamate increased the ALAD activity in the in vitro enzymatic preparations obtained from the sorbitol-treated leaf segments; sorbitol inhibited the ALAD activity in the preparations from both sorbitol-treated and untreated leaves. It was suggested that sorbitol-induced osmotic stress inhibits the enzyme activity by affecting the ALAD induction during greening and regulating the ALAD steady-state level of ALAD in leaf cells. The protective effect of glutamate on ALAD in the preparations from the sorbitol-treated leaves might be due to its stimulatory effect on the enzyme.

Improving Performance and Operational Stability of Porcine Interferon-α Production by Pichia pastoris with Combinational Induction Strategy of Low Temperature and Methanol/Sorbitol Co-feeding.

Science.gov (United States)

Gao, Min-Jie; Zhan, Xiao-Bei; Gao, Peng; Zhang, Xu; Dong, Shi-Juan; Li, Zhen; Shi, Zhong-Ping; Lin, Chi-Chung

2015-05-01

Various induction strategies were investigated for effective porcine interferon-α (pIFN-α) production by Pichia pastoris in a 10 L fermenter. We found that pIFN-α concentration could be significantly improved with the strategies of low-temperature induction or methanol/sorbitol co-feeding. On this basis, a combinational strategy of induction at lower temperature (20 °C) with methanol/sorbitol co-feeding has been proposed for improvement of pIFN-α production. The results reveal that maximal pIFN-α concentration and antiviral activity reach the highest level of 2.7 g/L and 1.8 × 10(7) IU/mg with the proposed induction strategy, about 1.3-2.1 folds higher than those obtained with other sub-optimal induction strategies. Metabolic analysis and online multi-variable measurement results indicate that energy metabolic enrichment is responsible for the performance enhancement of pIFN-α production, as a large amount of ATP could be simultaneously produced from both formaldehyde oxidation pathway in methanol metabolism and tricarboxylic acid (TCA) cycle in sorbitol metabolism. In addition, the proposed combinational induction strategy enables P. pastoris to be resistant to high methanol concentration (42 g/L), which conceivably occur associating with the error-prone methanol over-feeding. As a result, the proposed combinational induction strategy simultaneously increased the targeted protein concentration and operational stability leading to significant improvement of pIFN-α production.

A fiber-optic sorbitol biosensor based on NADH fluorescence detection toward rapid diagnosis of diabetic complications.

Science.gov (United States)

Gessei, Tomoko; Arakawa, Takahiro; Kudo, Hiroyuki; Mitsubayashi, Kohji

2015-09-21

Accumulation of sorbitol in the tissue is known to cause microvascular diabetic complications. In this paper, a fiber-optic biosensor for sorbitol which is used as a biomarker of diabetic complications was developed and tested. The biosensor used a sorbitol dehydrogenase from microorganisms of the genus Flavimonas with high substrate specificity and detected the fluorescence of reduced nicotinamide adenine dinucleotide (NADH) by the enzymatic reaction. An ultraviolet light emitting diode (UV-LED) was used as the excitation light source of NADH. The fluorescence of NADH was detected using a spectrometer or a photomultiplier tube (PMT). The UV-LED and the photodetector were coupled using a Y-shaped optical fiber. In the experiment, an optical fiber probe with a sorbitol dehydrogenase immobilized membrane was placed in a cuvette filled with a phosphate buffer containing the oxidized form of nicotinamide adenine dinucleotide (NAD(+)). The changes in NADH fluorescence intensity were measured after adding a standard sorbitol solution. According to the experimental assessment, the calibration range of the sorbitol biosensor systems using a spectrometer and a PMT was 5.0-1000 μmol L(-1) and 1.0-1000 μmol L(-1), respectively. The sorbitol biosensor system using the sorbitol dehydrogenase from microorganisms of the genus Flavimonas has high selectivity and sensitivity compared with that from sheep liver. The sorbitol biosensor allows for point-of-care testing applications or daily health care tests for diabetes patients.

The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

Science.gov (United States)

Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

2015-07-01

To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sorbitol treatment extends lifespan and induces the osmotic stress response in Caenorhabditis elegans

Directory of Open Access Journals (Sweden)

Devon eChandler-Brown

2015-10-01

Full Text Available The response to osmotic stress is a highly conserved process for adapting to changing environmental conditions. Prior studies have shown that hyperosmolarity by addition of sorbitol to the growth medium is sufficient to increase both chronological and replicative lifespan in the budding yeast, Saccharomyces cerevisiae. Here we report a similar phenomenon in the nematode Caenorhabditis elegans. Addition of sorbitol to the nematode growth medium induces an adaptive osmotic response and increases C. elegans lifespan by about 35%. Lifespan extension from 5% sorbitol behaves similarly to dietary restriction in a variety of genetic backgrounds, increasing lifespan additively with mutation of daf-2(e1370 and independently of daf-16(mu86, sir-2.1(ok434, aak-2(ok524, and hif-1(ia04. Dietary restriction by bacterial deprivation or mutation of eat-2(ad1113 fails to further extend lifespan in the presence of 5% sorbitol. Two mutants with constitutive activation of the osmotic response, osm-5(p813 and osm-7(n1515, were found to be long-lived, and lifespan extension from sorbitol required the glycerol biosynthetic enzymes GPDH-1 and GPDH-2. Taken together, these observations demonstrate that exposure to sorbitol at levels sufficient to induce an adaptive osmotic response extends lifespan in worms and define the osmotic stress response pathway as a longevity pathway conserved between yeast and nematodes.

Effect of Sorbitol Plasticizer on the Structure and Properties of Melt Processed Polyvinyl Alcohol Films.

Science.gov (United States)

Tian, Huafeng; Liu, Di; Yao, Yuanyuan; Ma, Songbai; Zhang, Xing; Xiang, Aimin

2017-12-01

Poly (vinyl alcohol) (PVA) possesses wide applications as food packaging materials, but is difficult to melt process for its strong inter/intra hydrogen bonding. In this work, flexible PVA films with different content of sorbitol plasticizers were prepared by melt processing with the assistance of water. And the influence of sorbitol plasticizer content on the crystallinity, optical transparency, water-retaining capability, mechanical properties, thermal stability and oxygen and water permeability were investigated. The results indicated that sorbitol dramatically improved the melt processing ability of PVA. Sorbitol could interact with PVA to form strong hydrogen bonding interactions, which would decrease the original hydrogen bonding of the matrix, resulting in the decrease of crystallinity degrees. The glass transition, melting and crystallization peak temperatures decreased with the increase of sorbitol. All the films exhibited fine optical transparency. The water retaining capability were improved with the increase of sorbitol. Especially, an increase in elongation at break and decrease in Young's modulus and tensile strength were observed indicating good plasticizing effect of sorbitol on PVA films. In addition, the PVA films prepared in this work exhibited fine barrier properties against oxygen and water, suggesting wide application potential as packaging materials. © 2017 Institute of Food Technologists®.

75 FR 16839 - Sorbitol From France

Science.gov (United States)

2010-04-02

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-44 (Third Review)] Sorbitol From France AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject review. DATES: Effective Date: Date of Commission approval. FOR FURTHER INFORMATION CONTACT: Dana Lofgren (202...

Biosynthesis of sorbitol and other compounds in Golden Delicious apple leaves

International Nuclear Information System (INIS)

Steenkamp, J.; Terblanche, J.H.; De Villiers, O.T.

1981-01-01

The distribution of radioactivity in the principal alcohol-soluble fractions of Golden Delicious apple leaves after exposure to 14 CO 2 for periods from 5 s to 60 min showed that the main products of photosynthesis were located in the phosphorylated and sugar fractions. Although the phosphorylated fraction consistently contained the highest radioactivity, no attempt was made to separate and identify the different compounds. As the percentage activity in the sugar (and sorbitol) and phosphorylated fractions increased with time, that in the organic acid and amino acid fractions decreased. Since the sugar and sorbitol fraction contained 45% of the total radioactivity after 60 min exposure to 14 CO 2 , and since sorbitol contained 82% of the radioactivity in this fraction, it appears that sorbitol is the principal non-phosphorylated end-product of photosynthesis in Golden Delicious apple leaves. Similar results were obtained with plum and apricot leaves. Since after only 60 s of photosynthesis sorbitol contained the highest radioactivity, it is apparent that the formation of this compound is very rapid, plays a role in the metabolism of Golden Delicious apple leaves, and that it is probably associated with the chloroplasts, as was found for plum leaves. The fact that amino acids and other organic acids also contained an appreciable amount of radioactivity (especially after short periods of photosynthesis) indicates a close relationship between these compounds and the primary products of photosynthesis

Host cell interactions of outer membrane vesicle-associated virulence factors of enterohemorrhagic Escherichia coli O157: Intracellular delivery, trafficking and mechanisms of cell injury

Science.gov (United States)

Greune, Lilo; Jarosch, Kevin-André; Steil, Daniel; Zhang, Wenlan; He, Xiaohua; Lloubes, Roland; Fruth, Angelika; Kim, Kwang Sik; Schmidt, M. Alexander; Dobrindt, Ulrich; Mellmann, Alexander; Karch, Helge

2017-01-01

Outer membrane vesicles (OMVs) are important tools in bacterial virulence but their role in the pathogenesis of infections caused by enterohemorrhagic Escherichia coli (EHEC) O157, the leading cause of life-threatening hemolytic uremic syndrome, is poorly understood. Using proteomics, electron and confocal laser scanning microscopy, immunoblotting, and bioassays, we investigated OMVs secreted by EHEC O157 clinical isolates for virulence factors cargoes, interactions with pathogenetically relevant human cells, and mechanisms of cell injury. We demonstrate that O157 OMVs carry a cocktail of key virulence factors of EHEC O157 including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, and flagellin. The toxins are internalized by cells via dynamin-dependent endocytosis of OMVs and differentially separate from vesicles during intracellular trafficking. Stx2a and CdtV-B, the DNase-like CdtV subunit, separate from OMVs in early endosomes. Stx2a is trafficked, in association with its receptor globotriaosylceramide within detergent-resistant membranes, to the Golgi complex and the endoplasmic reticulum from where the catalytic Stx2a A1 fragment is translocated to the cytosol. CdtV-B is, after its retrograde transport to the endoplasmic reticulum, translocated to the nucleus to reach DNA. CdtV-A and CdtV-C subunits remain OMV-associated and are sorted with OMVs to lysosomes. EHEC hemolysin separates from OMVs in lysosomes and targets mitochondria. The OMV-delivered CdtV-B causes cellular DNA damage, which activates DNA damage responses leading to G2 cell cycle arrest. The arrested cells ultimately die of apoptosis induced by Stx2a and CdtV via caspase-9 activation. By demonstrating that naturally secreted EHEC O157 OMVs carry and deliver into cells a cocktail of biologically active virulence factors, thereby causing cell death, and by performing first comprehensive analysis of intracellular trafficking of OMVs and OMV-delivered virulence factors

Adherence of Enterohemorrhagic Escherichia coli to Human Epithelial Cells: The Role of Intimin

Science.gov (United States)

1995-04-28

mucosa (e.g., enterotoxigenic E. coli, Vibrio cholerae , and Boroetella pertussis); ii) damage to the epithelial cell microvilli induced by the...diarrhea in Mayan childm in Mexico . J. Infect. Dis. 163, 507-513. G6mez-Ouarte, O.G. and Kaper, J.B. (1995). A plasmid-encoded regulartory region...de la Cabaca, F., and Garibay, E.V. (1987). Enteroadherent Escherichia coli as a cause of diarrhea among children in Mexico . J . Clin. Microbiol. 25

A biopolymer-based carbon nanotube interface integrated with a redox shuttle and a D-sorbitol dehydrogenase for robust monitoring of D-sorbitol

International Nuclear Information System (INIS)

Sefcovicova, J.; Filip, J.; Gemeiner, P.; Bucko, M.; Magdolen, P.; Tkac, J.; Tomcik, P.

2011-01-01

We describe the preparation and characterization of a glassy carbon electrode modified with a bionanocomposite consisting of a hyaluronic acid, dispersed carbon nanotubes, and electrostatically bound toluidine blue. The electrode was used to detect NADH in the batch and flow-injection mode of operation. The electrode was further modified by immobilizing sorbitol dehydrogenase to result in biosensor for D-sorbitol that displays good operational stability, a sensitivity of 10.6 μA mM -1 cm -2 , a response time of 16 s, and detection limit in the low micromolar range. The biosensor was successfully applied to off-line monitoring of D-sorbitol during its bioconversion into L-sorbose (a precursor in the synthesis of vitamin C) by Gluconobacter oxydans. The sample assay precision is 2.5% (an average RSD) and the throughput is 65 h -1 if operated in the flow-injection mode. The validation of this biosensor against a reference HPLC method resulted in a slope of correlation of 1.021 ± 0.001 (R 2 = 0.99997). (author)

Comparison of the effect of sorbitol and glucose on calcium absorption in postmenopausal women

International Nuclear Information System (INIS)

Francis, R.M.; Peacock, M.; Barkworth, S.A.; Marshall, D.H.

1986-01-01

It has been suggested that the oral administration of sorbitol promotes calcium absorption, while glucose has no effect. We have therefore compared the effect of oral sorbitol and glucose on the absorption of radiocalcium from low and high carrier loads in healthy postmenopausal women. In a control group of 20 women given neither sorbitol nor glucose, the mean +/- SEM fractional radiocalcium absorption rate from a low carrier load was 0.65 +/- 0.05 (fraction of dose/h). In a second group of 10 women the fractional absorption rate from the low carrier load was lower (p less than 0.05) with 10 g sorbitol (0.48 +/- 0.05) than with 10 g glucose (0.65 +/- 0.08). Fractional absorption of radiocalcium from a high carrier load measured in a third group of seven women using two isotopes (oral 45Ca, IV 47Ca) was also lower (p less than 0.001) with 10 g sorbitol (0.22 +/- 0.01, fraction/3 h) than with 10 g glucose (0.29 +/- 0.02). The results suggest that calcium absorption from a low carrier load is unaltered by glucose but that absorption of calcium from both low and high carrier loads is lower with sorbitol than with glucose

An exploratory study; the therapeutic effects of premixed activated charcoal-sorbitol administration in patients poisoned with organophosphate pesticide.

Science.gov (United States)

Moon, Jeongmi; Chun, Byeongjo; Song, Kyounghwan

2015-02-01

The effects of activated charcoal (AC) mixed with cathartics for gastric decontamination in the management of organophosphate (OP) poisoning remain unknown due to limited clinical evidence. This exploratory study assessed the effectiveness of premixed AC-sorbitol as a treatment for OP poisoning. This retrospective observational case study included patients who either did not receive AC-sorbitol or received a single dose of AC-sorbitol within 24 h after OP ingestion. The patients were divided into three groups: no AC-sorbitol treatment, patients who received AC-sorbitol within 1 h of OP ingestion, and patients who received AC-sorbitol more than 1 h after OP ingestion. Mortality, the development of respiratory failure, and the duration of mechanical ventilation were used as outcome measurements for effectiveness, whereas aspiration pneumonia and electrolyte imbalance were employed as safety measurements. Among 262 patients with OP poisoning, 198 were included. Of these, 133 patients did not receive AC-sorbitol, whereas 14 and 51 patients received AC-sorbitol within 1 h or more than 1 h after ingestion, respectively. The time from ingestion to hospital arrival and time from ingestion to administration of atropine and pralidoxime differed among the groups, whereas other characteristics, including age, amount ingested, and type of ingested OP, were similar among the groups. Univariate and multivariate analysis demonstrated that the administration of AC-sorbitol was not associated with outcome measures for effectiveness and did not significantly increase either aspiration pneumonia or electrolyte imbalances during hospitalization. The administration of AC-sorbitol exerted neither beneficial nor harmful effects on the outcomes of OP-poisoned patients regardless of the time from OP ingestion to administration, compared with those of patients who did not receive AC-sorbitol. However, this study enrolled a small number of patients who received AC-sorbitol; further qualified

Follow-up of coeliac disease with the novel one-hour 13C-sorbitol breath test versus the H2-sorbitol breath test.

Science.gov (United States)

Tveito, Kari; Hetta, Anne Kristine; Askedal, Mia; Brunborg, Cathrine; Sandvik, Leiv; Løberg, Else Marit; Skar, Viggo

2011-07-01

We recently developed a (13)C-sorbitol breath test ((13)C-SBT) as an alternative to the H(2)-sorbitol breath test (H(2)-SBT) for coeliac disease. In this study we compared the diagnostic properties of the H(2)-SBT and the (13)C-SBT in follow-up of coeliac disease. Twenty-seven coeliac patients on a gluten-free diet (GFD) performed the breath tests. All had been tested before treatment in the initial study of the (13)C-SBT, in which 39 untreated coeliac patients, 40 patient controls, and 26 healthy volunteers participated. Five gram sorbitol and 100 mg (13)C-sorbitol were dissolved in 250 ml tap water and given orally. H(2), CH(4) and (13)CO(2) were measured in end-expiratory breath samples every 30 min for 4 h. Increased H(2) concentration ≥20 ppm from basal values was used as cut-off for the H(2)-SBT. Sixty minutes values were used as diagnostic index in the (13)C-SBT. (13)CO(2) levels at 60 min increased in 20/26 treated coeliac patients (77%) after GFD, but were significantly lower than in control groups. Out of 20 patients who had a positive H(2)-SBT before GFD, 12 had a negative H(2)-SBT after GFD. Peak H(2) concentrations were not correlated with (13)C-SBT results. The study confirms the sensitivity of a one-hour (13)C-SBT for small intestinal malabsorption. The (13)C-SBT has superior diagnostic properties compared with the H(2)-SBT in follow-up of coeliac disease.

Ileocolic perforation secondary to sodium polystyrene sulfonate in sorbitol use: A case report

Science.gov (United States)

Trottier, Vincent; Drolet, Sébastien; Morcos, Mohib W

2009-01-01

Hyperkalemia is a common condition encountered in medical and surgical patients. It can lead to various complications including cardiac arrhythmias. Sodium polystyrene sulfonate (SPS) in sorbitol is an ion-exchange resin that can be used to treat hyperkalemia. It can be used in enema or in oral form. The present article describes the case of an intensive care unit patient who experienced severe, diffuse, intestinal perforation induced by the use of SPS-sorbitol, requiring multiple laparotomies, followed by a brief review of the relevant literature and recommendations regarding the use of SPS-sorbitol. PMID:19826644

The effect of glicerol and sorbitol plasticizers toward disintegration time of phyto-capsules

Science.gov (United States)

Pudjiastuti, Pratiwi; Hendradi, Esti; Wafiroh, Siti; Harsini, Muji; Darmokoesoemo, Handoko

2016-03-01

The aim of research is determining the effect of glycerol and sorbitol toward the disintegration time of phyto-capsules, originated capsules from plant polysaccharides. Phyto-capsules were made from polysaccharides and 0.5% (v/v) of glycerol and sorbitol of each. The seven capsules of each were determined the disintegration time using Erweka disintegrator. The mean of disintegration time of phyto-capsules without plasticizers, with glycerol and sorbitol were 25'30"; 45'15" and 35'30" respectively. The color and colorless gelatin capsules showed the mean of disintegration time 7'30" and 2'35" respectively.

Autodisplay of active sorbitol dehydrogenase (SDH) yields a whole cell biocatalyst for the synthesis of rare sugars.

Science.gov (United States)

Jose, Joachim; von Schwichow, Steffen

2004-04-02

Whole cell biocatalysts are attractive technological tools for the regio- and enantioselective synthesis of products, especially from substrates with several identical reactive groups. In the present study, a whole cell biocatalyst for the synthesis of rare sugars from polyalcohols was constructed. For this purpose, sorbitol dehydrogenase (SDH) from Rhodobacter sphaeroides, a member of the short-chain dehydrogenase/reductase (SDR) family, was expressed on the surface of Escherichia coli using Autodisplay. Autodisplay is an efficient surface display system for Gram-negative bacteria and is based on the autotransporter secretion pathway. Transport of SDH to the outer membrane was monitored by SDS-PAGE and Western blotting of different cell fractions. The surface exposure of the enzyme could be verified by immunofluorescence microscopy and fluorescence activated cell sorting (FACS). The activity of whole cells displaying SDH at the surface was determined in an optical test. Specific activities were found to be 12 mU per 3.3 x 10(8) cells for the conversion of D-glucitol (sorbitol) to D-fructose, 7 mU for the conversion D-galactitol to D-tagatose, and 17 mU for the conversion of L-arabitol to L-ribulose. The whole cell biocatalyst obtained by surface display of SDH could also produce D-glucitol from D-fructose (29 mU per 3.3 x 10(8) cells).

Management of constipation in residents with dementia: sorbitol effectiveness and cost.

Science.gov (United States)

Volicer, Ladislav; Lane, Patricia; Panke, JoAnn; Lyman, Paul

2004-01-01

The objective of this report is to describe a cost-effective strategy for management of constipation in nursing home residents with dementia. We conducted a prospective observational quality improvement study of 41 residents with chronic constipation and receiving an osmotic laxative. Sorbitol was substituted for lactulose. The study was conducted at a dementia special care unit at a Veterans Administration hospital. We measured the number and amount of laxative use over a period of 4 weeks that were required to maintain regular bowel function. There was no difference in efficacy of lactulose and sorbitol. Use of additional laxatives was infrequent: Milk of Magnesia on approximately 10% of days/patient, bisacodyl suppository on 2% to 4% of days/patient, and Fleet enema only on 3 occasions. The cost of constipation management using routine administration of sorbitol and as-needed use of other laxatives was 27% to 55% lower than the cost of other constipation management strategies reported in the literature. Substitution of sorbitol for lactulose does not change efficacy of the treatment and decreases cost. Regular use of an osmotic laxative avoids the costs and discomforts of rectal laxatives.

Semi-industrial scale (30 m3) fed-batch fermentation for the production of D-lactate by Escherichia coli strain HBUT-D15.

Science.gov (United States)

Fu, Xiangmin; Wang, Yongze; Wang, Jinhua; Garza, Erin; Manow, Ryan; Zhou, Shengde

2017-02-01

D(-)-lactic acid is needed for manufacturing of stereo-complex poly-lactic acid polymer. Large scale D-lactic acid fermentation, however, has yet to be demonstrated. A genetically engineered Escherichia coli strain, HBUT-D, was adaptively evolved in a 15% calcium lactate medium for improved lactate tolerance. The resulting strain, HBUT-D15, was tested at a lab scale (7 L) by fed-batch fermentation with up to 200 g L -1 of glucose, producing 184-191 g L -1 of D-lactic acid, with a volumetric productivity of 4.38 g L -1  h -1 , a yield of 92%, and an optical purity of 99.9%. The HBUT-D15 was then evaluated at a semi-industrial scale (30 m 3 ) via fed-batch fermentation with up to 160 g L -1 of glucose, producing 146-150 g L -1 of D-lactic acid, with a volumetric productivity of 3.95-4.29 g L -1  h -1 , a yield of 91-94%, and an optical purity of 99.8%. These results are comparable to that of current industrial scale L(+)-lactic acid fermentation.

Modeling the survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium during fermentation, drying, and storage of soudjouk-style fermented sausage.

Science.gov (United States)

Hwang, Cheng-An; Porto-Fett, Anna C S; Juneja, Vijay K; Ingham, Steven C; Ingham, Barbara H; Luchansky, John B

2009-02-28

This study quantified and modeled the survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Typhimurium in soudjouk-style fermented sausage during fermentation, drying, and storage. Batter prepared from ground beef (20% fat), seasonings, starter culture, and dextrose was separately inoculated with a multi-strain mixture of each pathogen to an initial inoculum of ca. 6.5 log(10) CFU/g in the batter. The sausages were subsequently fermented at 24 degrees C with a relative humidity (RH) of 90% to 95% for 3 to 5 days to ca. pH 5.2, pH 4.9 or pH 4.6, then dried at 22 degrees C to a(w) 0.92, a(w) 0.89, or a(w) 0.86, respectively, and then stored at 4, 21, or 30 degrees C for up to 60 days. Lethality of the three pathogens was modeled as a function of pH, a(w) and/or storage temperature. During fermentation to pH 5.2 to pH 4.6, cell reductions ranged from 0 to 0.9 log(10) CFU/g for E. coli O157:H7, 0.1 to 0.5 log(10) CFU/g for L. monocytogenes, and 0 to 2.2 log(10) CFU/g for S. Typhimurium. Subsequent drying of sausages of pH 5.2 to pH 4.6 at 22 degrees C with 80% to 85% RH for 3 to 7 days to a(w) of 0.92 to a(w) 0.86 resulted in additional reductions that ranged from 0 to 3.5 log(10) CFU/g for E. coli O157:H7, 0 to 0.4 log(10) CFU/g for L. monocytogenes, and 0.3 to 2.4 log(10) CFU/g for S. Typhimurium. During storage at 4, 21, or 30 degrees C the reduction rates of the three pathogens were generally higher (pfermentation, drying, and storage. The applicability of the resulting models for fermented sausage was evaluated by comparing model predictions with published data. Pathogen reductions estimated by the models for E. coli O157:H7 and S. Typhimurium were comparable to 67% and 73% of published data, respectively. Due to limited published data for L. monocytogenes, the models for L. monocytogenes would need additional validations. Results of pathogen reductions from this study may be used as a reference to assist manufacturers of soudjouk

Fermentation of sweet whey by recombinant Escherichia coli K011 Fermentação de soro de leite por Escherichia coli KO11 recombinante

Directory of Open Access Journals (Sweden)

Amarildo Ricardo Leite

2000-09-01

Full Text Available The production of ethanol from sweet whey using the recombinant Escherichia coli KO11, in batch fermentation, was tested. The maximum ethanol yield was reached after 96h, representing only 38% of the theoretical yield. The supplementation of whey with components of LB broth increased the maximum yield to 96% in 72h. The addition of 0.5% yeast extract to whey resulted in maximum yield of 74% at 36h and it increased to over 100% when yeast extract and trace metals solution (Fe++, Mn++ and Zn++ were added.A produção de etanol a partir de soro de leite empregando a cepa Escherichia coli KO11 recombinante, em fermentação de batelada, foi testada. O rendimento máximo de etanol foi obtido em 96h, representando apenas 38% do rendimento teórico. A suplementação do soro com os componentes do caldo LB aumentou o rendimento para 96% em 72h. A adição de 0,5% de extrato de levedura ao soro resultou em um rendimento máximo de 74% em 36h que aumentou para acima de 100% quando se adicionou extrato de levedura e uma solução de metais traço (Fe++, Mn++ e Zn++.

Cloning, Expression, and Characterization of Sorbitol Transporters from Developing Sour Cherry Fruit and Leaf Sink Tissues1

Science.gov (United States)

Gao, Zhifang; Maurousset, Laurence; Lemoine, Remi; Yoo, Sang-Dong; van Nocker, Steven; Loescher, Wayne

2003-01-01

The acyclic polyol sorbitol is a primary photosynthetic product and the principal photosynthetic transport substance in many economically important members of the family Rosaceace (e.g. almond [Prunus dulcis (P. Mill.) D.A. Webber], apple [Malus pumila P. Mill.], cherry [Prunus spp.], peach [Prunus persica L. Batsch], and pear [Pyrus communis]). To understand key steps in long-distance transport and particularly partitioning and accumulation of sorbitol in sink tissues, we have cloned two sorbitol transporter genes (PcSOT1 and PcSOT2) from sour cherry (Prunus cerasus) fruit tissues that accumulate large quantities of sorbitol. Sorbitol uptake activities and other characteristics were measured by heterologous expression of PcSOT1 and PcSOT2 in yeast (Saccharomyces cerevisiae). Both genes encode proton-dependent, sorbitol-specific transporters with similar affinities (Km sorbitol of 0.81 mm for PcSOT1 and 0.64 mm for PcSOT2). Analyses of gene expression of these transporters, however, suggest different roles during leaf and fruit development. PcSOT1 is expressed throughout fruit development, but especially when growth and sorbitol accumulation rates are highest. In leaves, PcSOT1 expression is highest in young, expanding tissues, but substantially less in mature leaves. In contrast, PcSOT2 is mainly expressed only early in fruit development and not in leaves. Compositional analyses suggest that transport mediated by PcSOT1 and PcSOT2 plays a major role in sorbitol and dry matter accumulation in sour cherry fruits. Presence of these transporters and the high fruit sorbitol concentrations suggest that there is an apoplastic step during phloem unloading and accumulation in these sink tissues. Expression of PcSOT1 in young leaves before completion of the transition from sink to source is further evidence for a role in determining sink activity. PMID:12692316

Granule fraction inhomogeneity of calcium carbonate/sorbitol in roller compacted granules

DEFF Research Database (Denmark)

Bacher, Charlotte; Olsen, P.M.; Bertelsen, P.

2008-01-01

The granule fraction inhomogeneity of roller compacted granules was examined on mixtures of three different morphologic forms of calcium carbonate and three particle sizes of sorbitol. The granule fraction inhomogeneity was determined by the distribution of the calcium carbonate in each of the 10...... size fractions between 0 and 2000 µm and by calculating the demixing potential. Significant inhomogeneous occurrence of calcium carbonate in the size fractions was demonstrated, depending mostly on the particles sizes of sorbitol but also on the morphological forms of calcium carbonate......, the ability of the powder to agglomerate in the roller compactor was demonstrated to be related to the ability of the powder to be compacted into a tablet, thus the most compactable calcium carbonate and the smallest sized sorbitol improved the homogeneity by decreasing the demixing potential....

Effect of Secondary Doping Using Sorbitol on Structure and Transport Properties of PEDOT-PSS Thin Films

Science.gov (United States)

Khasim, Syed; Pasha, Apsar; Roy, Aashish S.; Parveen, Ameena; Badi, Nacer

2017-07-01

Poly(3,4-ethylene dioxythiophene):poly(styrenesulphonate) (PEDOT-PSS) in the recent past has emerged as one of the most fascinating conducting polymers for many device applications. The unique feature of PEDOT-PSS is its transparency in the entire visible spectrum with excellent thermal stability. The PEDOT-PSS as prepared as an aqueous dispersion has very low conductivity, and it hinders the performance of a device. In this work we report the conductivity enhancement of PEDOT-PSS thin films through secondary doping using a polar organic solvent such as sorbitol. The mechanism of conductivity enhancement was studied through various physical and chemical characterizations. The effect of sorbitol concentration on structure and transport properties of PEDOT-PSS thin films was investigated in detail. The structural and morphological modifications in PEDOT-PSS due to the addition of sorbitol was studied through Fourier transform spectroscopy, Ultra Violet-visible spectroscopy, theromogravimetric analysis, scanning electron microscopy and atomic force microscopy. The interactions resulting from conformational changes of PEDOT chains that changes from coiled to linear structure due to the sorbitol treatment significantly improves the conductivity of PEDOT-PSS films. The secondary doping of sorbitol reduces the energy barrier that facilitates the charge carrier hopping leading to enhanced conductivity. We have observed that the conductivity of PEDOT-PSS thin films was increased by two fold due to sorbitol treatment when compared to conductivity of pure PEDOT-PSS. We have carried out detailed analysis of dielectric parameters of sorbitol-treated PEDOT-PSS films and found that sorbitol treatment has a significant effect on various dielectric attributes of PEDOT-PSS films. Hence, secondary doping using sorbitol could be a useful way to effectively tailor the conductivity and dielectric properties of PEDOT-PSS thin films that can be used as flexible electrodes in

Sorbitol-modified hyaluronic acid reduces oxidative stress, apoptosis and mediators of inflammation and catabolism in human osteoarthritic chondrocytes.

Science.gov (United States)

Mongkhon, John-Max; Thach, Maryane; Shi, Qin; Fernandes, Julio C; Fahmi, Hassan; Benderdour, Mohamed

2014-08-01

Our study was designed to elucidate the precise molecular mechanisms by which sorbitol-modified hyaluronic acid (HA/sorbitol) exerts beneficial effects in osteoarthritis (OA). Human OA chondrocytes were treated with increasing doses of HA/sorbitol ± anti-CD44 antibody or with sorbitol alone and thereafter with or without interleukin-1beta (IL-1β) or hydrogen peroxide (H2O2). Signal transduction pathways and parameters related to oxidative stress, apoptosis, inflammation, and catabolism were investigated. HA/sorbitol prevented IL-1β-induced oxidative stress, as measured by reactive oxygen species, p47-NADPH oxidase phosphorylation, 4-hydroxynonenal (HNE) production and HNE-metabolizing glutathione-S-transferase A4-4 expression. Moreover, HA/sorbitol stifled IL-1β-induced metalloproteinase-13, nitric oxide (NO) and prostaglandin E2 release as well as inducible NO synthase expression. Study of the apoptosis process revealed that this gel significantly attenuated cell death, caspase-3 activation and DNA fragmentation elicited by exposure to a cytotoxic H2O2 dose. Examination of signaling pathway components disclosed that HA/sorbitol prevented IL-1β-induced p38 mitogen-activated protein kinase and nuclear factor-kappa B activation, but not that of extracellular signal-regulated kinases 1 and 2. Interestingly, the antioxidant as well as the anti-inflammatory and anti-catabolic effects of HA/sorbitol were attributed to sorbitol and HA, respectively. Altogether, our findings support a beneficial effect of HA/sorbitol in OA through the restoration of redox status and reduction of apoptosis, inflammation and catabolism involved in cartilage damage.

Caloric restriction counteracts age-related changes in the activities of sorbitol metabolizing enzymes from mouse liver

Science.gov (United States)

Hagopian, Kevork; Ramsey, Jon J.; Weindruch, Richard

2009-01-01

The influence of caloric restriction (CR) on hepatic sorbitol-metabolizing enzyme activities was investigated in young and old mice. Aldose reductase and sorbitol dehydrogenase activities were significantly lower in old CR mice than in old controls. Young CR mice showed decreased aldose reductase activity and a trend towards decreased sorbitol dehydrogenase when compared to controls. Metabolites of the pathway, namely sorbitol, glucose and fructose were decreased by CR in young and old mice. Pyruvate levels were decreased by CR in both young and old mice, while lactate decreased only in old CR. Malate levels increased in old CR but remained unchanged in young CR, when compared with controls. Accordingly, the lactae/pyruvate and malate/pyruvate ratios in young and old CR mice were increased, indicating increased NADH/NAD and NADPH/NADP redox couples, respectively. The results indicate that decreased glucose levels under CR conditions lead to decreased sorbitol pathway enzyme activities and metabolite levels, and could contribute to the beneficial effects of long-term CR through decreased sorbitol levels and NADPH sparing. PMID:18953666

Physicochemical, mechanical and thermal properties of chitosan films with and without sorbitol.

Science.gov (United States)

Liu, Mei; Zhou, Yibin; Zhang, Yang; Yu, Chen; Cao, Shengnan

2014-09-01

The effect of sorbitol on the physicochemical, mechanical and thermal properties of chitosan films with different degrees of deacetylation (DD; i.e., DD85% and DD95%) was investigated. The thickness, moisture content (MC), water solubility (WS) and water-vapor permeability (WVP) of the films were evaluated. Sorbitol addition reduced MC, increased WS and significantly (psorbitol increased the strain and decreased stress for both DD films, but DD95% could sustain higher strain and DD85% could sustain higher stress. Thermogravimetrics analysis and differential scanning calorimetry showed that sorbitol elicited a lower degradation temperature for both films, and that DD95% films exhibited higher thermal stability than DD85% films. Copyright © 2014 Elsevier B.V. All rights reserved.

Ileocolic Perforation Secondary to Sodium Polystyrene Sulfonate in Sorbitol Use: A Case Report

Directory of Open Access Journals (Sweden)

Vincent Trottier

2009-01-01

Full Text Available Hyperkalemia is a common condition encountered in medical and surgical patients. It can lead to various complications including cardiac arrhythmias. Sodium polystyrene sulfonate (SPS in sorbitol is an ion-exchange resin that can be used to treat hyperkalemia. It can be used in enema or in oral form. The present article describes the case of an intensive care unit patient who experienced severe, diffuse, intestinal perforation induced by the use of SPS-sorbitol, requiring multiple laparotomies, followed by a brief review of the relevant literature and recommendations regarding the use of SPS-sorbitol.

Molecular dynamics studies of the conformation of sorbitol

Science.gov (United States)

Lerbret, A.; Mason, P.E.; Venable, R.M.; Cesàro, A.; Saboungi, M.-L.; Pastor, R.W.; Brady, J.W.

2009-01-01

Molecular dynamics simulations of a 3 m aqueous solution of D-sorbitol (also called D-glucitol) have been performed at 300 K, as well as at two elevated temperatures to promote conformational transitions. In principle, sorbitol is more flexible than glucose since it does not contain a constraining ring. However, a conformational analysis revealed that the sorbitol chain remains extended in solution, in contrast to the bent conformation found experimentally in the crystalline form. While there are 243 staggered conformations of the backbone possible for this open-chain polyol, only a very limited number were found to be stable in the simulations. Although many conformers were briefly sampled, only eight were significantly populated in the simulation. The carbon backbones of all but two of these eight conformers were completely extended, unlike the bent crystal conformation. These extended conformers were stabilized by a quite persistent intramolecular hydrogen bond between the hydroxyl groups of carbon C-2 and C-4. The conformational populations were found to be in good agreement with the limited available NMR data except for the C-2–C-3 torsion (spanned by the O-2–O-4 hydrogen bond), where the NMR data supports a more bent structure. PMID:19744646

The metabolism of sorbitol and fructose in isolated chloroplasts of Santa Rosa plum leaves

International Nuclear Information System (INIS)

De Villiers, O.T.

1979-01-01

Aqueously as well as non-aqueously isolated chloroplasts from Santa Rosa plum leaves readily metabolised sorbitol- 14 C to fructose, glucose and sucrose. Likewise, fructose- 14 C was converted to sorbitol, glucose and sucrose [af

Colonic necrosis due to calcium polystyrene sulfonate (Kalimate not suspended in sorbitol

Directory of Open Access Journals (Sweden)

María Dolores Castillo-Cejas

2013-04-01

Full Text Available Cation-exchange resins are used in the management of hyperkalemia, particularly in patients with end-stage renal disease. These resins were associated with gastrointestinal tract lesions, especially sodium polystyrene sulfonate (Kayexalate mixed with sorbitol. We present a case of colonic necrosis after the administration of calcium polystyrene sulfonate (Kalimate not suspended in sorbitol.

Translocation of sorbitol and other photosynthates in golden delicious apple shoots

International Nuclear Information System (INIS)

Steenkamp, J.; Terblanche, J.H.; De Villiers, O.T.

1982-01-01

This study was undertaken to determine to what extent sorbitol and other photosynthates are translocated in Golden Delicious apple shoots. The distribution of radioactivity in the different fractions, after the leaves had been exposed to radiocarbon, was found in segment of the shoots directly below the treatment leaves. The highest 14 C activity was in the carbohydrate fraction. The results indicate that sorbitol is the principal carbohydrate transported in Golden Delicious apple shoots

Effect of Guar Gum with Sorbitol Coating on the Properties and Oil Absorption of French Fries.

Science.gov (United States)

Jia, Bo; Fan, Daming; Li, Jinwei; Duan, Zhenhua; Fan, Liuping

2017-12-13

This paper investigated the effects of guar gum with sorbitol coating on the oil absorption of French fries by combined dye oil methods, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results showed that pretreatment of blanching with calcium ions and coating with guar gum and sorbitol could significantly reduce the structural oil (STO) and penetrated surface oil (PSO) of French fries and have no negative effects on its texture and also effectively control the final moisture content ( p French fries with guar gum and sorbitol reduced by 50.8%, 33.1% and 30.6%, respectively. CLSM photographs confirmed that STO significantly reduced after coating with guar gum and sorbitol, followed by PSO. In the process of frying, the coatings of guar gum or guar gum with sorbitol could effectively prevent oil from infiltrating the potato tissue, which can be seen in the SEM photographs. The barrier properties of French fries were enhanced by coating guar gum, and sorbitol was added to avoid pores and cracks. Blanching with calcium ion can significantly reduce the final moisture content of coating French fries.

Conductivity, work function, and environmental stability of PEDOT:PSS thin films treated with sorbitol

NARCIS (Netherlands)

Nardes, A.M.; Kemerink, M.; Kok, de M.M.; Vinken, E.; Maturova, K.; Janssen, R.A.J.

2008-01-01

The electrical properties of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) thin films deposited from aqueous dispersion using different concentrations of sorbitol have been studied in detail. Although it is well known that sorbitol enhances the conductivity of PEDOT:PSS thin

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced Tg.

Science.gov (United States)

Gustini, Liliana; Lavilla, Cristina; de Ilarduya, Antxon Martínez; Muñoz-Guerra, Sebastián; Koning, Cor E

2016-10-10

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated. The presence of bicyclic units resulted in enhanced T g with respect to the parent sorbitol-containing polyester lacking isohexides. The different capability of the two isohexides to boost the thermal properties confirmed the more flexible character provided by the isoidide diester derivative. Solvent-borne coatings were prepared by cross-linking the sugar-based polyester polyols with polyisocyanates. The increased rigidity of the obtained sugar-based polyester polyols led to an enhancement in hardness of the resulting coatings.

The relationship between sucrose hydrolysis, sorbitol formation and mineral ion concentration during bioethanol formation using Zymomonas mobilis 2716

Energy Technology Data Exchange (ETDEWEB)

Doelle, M.B.; Doelle, H.W. (Queensland Univ., St. Lucia (Australia). Dept. of Microbiology); Greenfield, P.F. (Queensland Univ., St. Lucia (Australia). Dept. of Chemical Engineering)

1990-11-01

Investigations into the relationship between sucrose hydrolysis, sorbitol formation and mineral ion concentration during bioethanol formation by Zymomonas mobilis 2716 revealed two distinct phenomena responsible for carbon flow diversion, a 'sucrose effect' and a 'salt effect'. Neither of the two phenomena affects sucrose hydrolysis, but they divert carbon flow of the fructose monomer leading to its own accumulation, sorbitol or oligosaccharide formation. Sucrose concentrations in excess of 15% (w/v) led to sorbitol formation, the level of which may exceed 2% (w/v) depending upon glucose accumulation during sucrose hydrolysis. Increasing mineral ion concentrations led initially to carbon losses and finally to fructose accumulation instead of sorbitol formation. This carbon loss can be corrected by the addition of invertase, which in turn leads to an increase in sorbitol, fructose and ethanol. Potassium and chloride are the dominant ions responsible for suppression of sorbitol formation and fructose uptake, encouraging oligosaccharide formation. These fructooligosaccharides must be of a type which can be converted to fructose, sorbitol and ethanol through the action of invertase. The requirement of invertase addition to prevent fructooligosaccharide formation is indirect evidence that Z. mobilis 2716 does not produce invertase. (orig.).

EFFECT OF XYLITOL AND SORBITOL IN CHEWING-GUMS ON MUTANS STREPTOCOCCI, PLAQUE PH AND MINERAL LOSS OF ENAMEL

NARCIS (Netherlands)

WENNERHOLM, K; ARENDS, J; BIRKHED, D; RUBEN, J; EMILSON, CG; DIJKMAN, AG

1994-01-01

Seventeen subjects with more than 3 x 10(5) mutans streptococci per millilitre of saliva completed this randomised, cross-over study. Four different chewing-gums, containing: (1) 70% xylitol, (2) 35% xylitol + 35% sorbitol, (3) 17.5% xylitol + 52.5% sorbitol, and (4) 70% sorbitol, were tested. The

Structure-property relation in HPMC polymer films plasticized with Sorbitol

Science.gov (United States)

Prakash, Y.; Somashekarappa, H.; Mahadevaiah, Somashekar, R.

2013-06-01

A correlation study on physical and mechanical properties of Hydroxy propyl-methylcellulose (HPMC) polymer films plasticized with different weight ratio of Sorbitol, prepared using solution casting method, was carried out using wide angle X-ray technique and universal testing machine. It is found that the crystallanity decreases as the concentration of Sorbitol increases up to a certain concentration and there afterwards increases. Measured Physical Properties like tensile strength decreases and elongation (%) increases indicating increase in the flexibility of the films. These observations confirm the correlation between microstructal parameters and mechanical properties of films. These films are suitable for packaging food products.

Effect of sorbitol and glycerol on the stability of trypsin and difference between their stabilization effects in the various solvents.

Science.gov (United States)

Pazhang, Mohammad; Mehrnejad, Faramarz; Pazhang, Yaghub; Falahati, Hanieh; Chaparzadeh, Nader

2016-01-01

The effect of glycerol and sorbitol on the stability of porcine pancreas trypsin was investigated in this work. Molecular dynamics simulation and thermostability results showed that trypsin has two flexible regions, and polyols (sorbitol and glycerol) stabilize the enzyme by decreasing the flexibility of these regions. Radial distribution function results exhibited that sorbitol and glycerol were excluded from the first water layer of the enzyme, therefore decrease the flexibility of the regions by preferential exclusion. Also, results showed that the stabilization effect of sorbitol is more than glycerol. This observation could be because of the larger decrease in the fluctuations of trypsin in the presence of sorbitol. We also examined the role of solvent's hydrophobicity in enzyme stabilization by sorbitol and glycerol. To do so, the thermostability of trypsin was evaluated in the presence of solvents with different hydrophobicity (methanol, ethanol, isopropanol and n-propanol) in addition to the polyols. Our results depicted that glycerol is a better stabilizer than sorbitol in the presence of hydrophobic solvents (n-propanol), whereas sorbitol is a better stabilizer than glycerol in the presence of hydrophilic solvents (methanol). © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Effect of sugar alcohol sorbitol on in vitro shoot development of Dianthus serotinus Waldst. et Kit.

Directory of Open Access Journals (Sweden)

Marković Marija

2014-01-01

Full Text Available The aim of this study was to investigate the effect of different concentrations of sorbitol on the development of the in vitro culture of D. serotinus in the multiplication phase. The obtained results showed that sorbitol generally had a positive effect, depending on its concentration and explant type. In addition, the presence of sorbitol affected the change of pH value of the media after autoclaving and after 25 days of in vitro culture, which could affect the availability of certain ions to plants. Therefore, the obtained results indicate that sorbitol can be used as an energy source for the in vitro culture of D. serotinus, but this should be further investigated. [Projekat Ministarstva nauke Republike Srbije, br. 43007

Effect of seasonal and geographical differences on skin and effect of treatment with an osmoprotectant: Sorbitol.

Science.gov (United States)

Muizzuddin, Neelam; Ingrassia, Michael; Marenus, Kenneth D; Maes, Daniel H; Mammone, Thomas

2013-01-01

Human skin maintains an optimal permeability barrier function in a terrestrial environment that varies considerably in humidity. Cells cultured under hyperosmotic stress accumulate osmolytes including sorbitol. Epidermal keratinocytes experience similar high osmolality under dry environmental conditions because of increased transepidermal water loss (TEWL) and concomitant drying of the skin. This study was designed to determine if epidermal keratinocytes, in vitro, could be protected from high osmotic stress, with the exogenous addition of sorbitol. In addition, we evaluated the effect of a formulation containing topical sorbitol on skin barrier and moisturization of subjects living in arid and humid regions in summer as well as in winter. Results from in vitro experiments showed that 50 mM sorbitol protected epidermal keratinocytes from osmotic toxicity induced by sodium chloride. Clinical studies indicated that skin chronically exposed to hot, dry environment appeared to exhibit stronger skin barrier and a lower baseline TEWL. In addition, skin barrier was stronger in summer than in winter. Sorbitol exhibited significant improvement in both barrier repair and moisturization, especially in individuals subjected to arid environmental conditions.

Antimicrobial potential of triticale stillage after lactic acid fermentation with Lactobacillus fermentum PL-1

OpenAIRE

Kujundžić Žužana; Dimić Gordana R.; Markov Siniša L.; Kocić-Tanackov Sunčica D.; Mojović Ljiljana V.; Pejin Jelena D.; Marković Milica N.

2013-01-01

This study is concerned with the testing of antimicrobial activity of triticale stillage obtained after lactic fermentation by Lactobacillus fermentum PL-1. The antimicrobial tests were performed using the disc-diffusion and agar well diffusion methods. It was found that fermented triticale stillage after lactic acid fermentation exhibited an inhibitory effect towards tested Gram positive and Gram negative bacteria: Escherichia coli, Salmonella enteritidis,...

Effect of nonabsorbed amounts of a fructose-sorbitol mixture on small intestinal transit in healthy volunteers

DEFF Research Database (Denmark)

Madsen, Jan L; Linnet, Jan; Rumessen, Jüri J

2006-01-01

Although malabsorption of small amounts of fructose-sorbitol mixtures occurs frequently in healthy humans, insights into their effects on gastrointestinal motility are poor. The present study addresses the hypothesis that malabsorption of a fructose-sorbitol challenge changes the small intestinal...... transit rate. Eleven healthy volunteers participated in a double-blind crossover investigation. In random order, the subjects ingested 30 g glucose or a mixture of 25 g fructose and 5 g sorbitol as 10% solutions. As a radiolabeled marker, (99m)Tc-diethylenetriaminepentaacetic acid was added to each test...... solution. Breath hydrogen and methane concentrations and gastrointestinal progress of the radiolabeled marker were followed for the next 6-hr period. Malabsorption of small amounts of the fructose-sorbitol mixture was evident in all subjects. The area under the gastric radioactivity-time curve after...

Effect of nonabsorbed amounts of a fructose-sorbitol mixture on small intestinal transit in healthy volunteers

DEFF Research Database (Denmark)

Madsen, Jan L; Linnet, Jan; Rumessen, Jüri J

2006-01-01

transit rate. Eleven healthy volunteers participated in a double-blind crossover investigation. In random order, the subjects ingested 30 g glucose or a mixture of 25 g fructose and 5 g sorbitol as 10% solutions. As a radiolabeled marker, (99m)Tc-diethylenetriaminepentaacetic acid was added to each test......Although malabsorption of small amounts of fructose-sorbitol mixtures occurs frequently in healthy humans, insights into their effects on gastrointestinal motility are poor. The present study addresses the hypothesis that malabsorption of a fructose-sorbitol challenge changes the small intestinal...... solution. Breath hydrogen and methane concentrations and gastrointestinal progress of the radiolabeled marker were followed for the next 6-hr period. Malabsorption of small amounts of the fructose-sorbitol mixture was evident in all subjects. The area under the gastric radioactivity-time curve after...

Sensitization of glycine (spectrophotometric read-out) dosimetric system using sorbitol

International Nuclear Information System (INIS)

Shinde, S.H.; Mukherjee, T.

2009-01-01

Glycine spectrophotometric read-out systems have a useful dose range of 15-4000 Gy. An attempt was made to sensitize it using sorbitol as a sensitizer. Optimum compositions of aqueous acidic solutions of ferrous ammonium sulphate-xylenol orange (XO), i.e. FX and sorbitol-ferrous ammonium sulphate-xylenol orange, i.e. SFX, for 400 mg of glycine, which gives maximum dosimetric response for any given dose, were established. Molar absorption coefficient values of ferric-XO-glycine complex, i.e. ε-values, were determined for glycine system in FX and SFX. These values were found to be 8410 and 15,000 m 2 mol -1 respectively, indicating that an enhancement or sensitivity factor of about 1.78 can be achieved by sorbitol for glycine in SFX. This factor was further confirmed by measuring the gamma dose response of glycine in FX and in SFX for four different doses, viz. 37.8, 75.5, 151 and 302 Gy. It was observed that dose response of glycine in SFX is about 77% more than that of glycine in FX. The maximum variation observed in response of glycine in FX or SFX was found to be within ±1.5%.

Comparison of 3% sorbitol vs psyllium fibre as oral contrast agents in MR enterography.

Science.gov (United States)

Saini, Sidharth; Colak, Errol; Anthwal, Shalini; Vlachou, Paraskevi A; Raikhlin, Antony; Kirpalani, Anish

2014-10-01

To compare the degree of small bowel distension achieved by 3% sorbitol, a high osmolarity solution, and a psyllium-based bulk fibre as oral contrast agents (OCAs) in MR enterography (MRE). This retrospective study was approved by our institutional review board. A total of 45 consecutive normal MRE examinations (sorbitol, n = 20; psyllium, n = 25) were reviewed. The patients received either 1.5 l of 3% sorbitol or 2 l of 1.6 g kg(-1) psyllium prior to imaging. Quantitative small bowel distension measurements were taken in five segments: proximal jejunum, distal jejunum, proximal ileum, distal ileum and terminal ileum by two independent radiologists. Distension in these five segments was also qualitatively graded from 0 (very poor) to 4 (excellent) by two additional independent radiologists. Statistical analysis comparing the groups and assessing agreement included intraclass coefficients, Student's t-test and Mann-Whitney U-test. Small bowel distension was not significantly different in any of the five small bowel segments between the use of sorbitol and psyllium as OCAs in both the qualitative (p = 0.338-0.908) and quantitative assessments (p = 0.083-0.856). The mean bowel distension achieved was 20.1 ± 2.2 mm for sorbitol and 19.8 ± 2.5 mm for psyllium (p = 0.722). Visualization of the ileum was good or excellent in 65% of the examinations in both groups. Sorbitol and psyllium are not significantly different at distending the small bowel and both may be used as OCAs for MRE studies. This is the first study to directly compare the degree of distension in MRE between these two common, readily available and inexpensive OCAs.

Children's acceptance of milk with xylitol or sorbitol for dental caries prevention

Directory of Open Access Journals (Sweden)

Castillo Ramon

2005-07-01

Full Text Available Abstract Background Xylitol, a polyol sugar, has been shown to reduce dental caries when mixed with food or chewing gum. This study examines the taste acceptability of xylitol in milk as a first step toward measuring the effectiveness of xylitol in milk for the reduction of dental caries in a public health program. Methods Three different types of milk (Ultra High Temperature (UHT, powder and evaporated were tested for acceptability by 75 Peruvian children (25 per milk group, ages 4 to 7 years. Each group evaluated xylitol and sorbitol in one type of milk. In the first phase, each child was presented with a tray of four plastic cups containing 50 ml of milk with 0.021 g/ml xylitol, 0.042 g/ml xylitol, 0.042 g/ml sorbitol or no sugar. Each child was asked to taste the samples in a self-selected order. After tasting each sample, the child placed the milk cup in front of one of three cartoon faces (smile, frown or neutral representing the child's response to the taste of each sample. In the second phase, the child was asked to rank order the milk samples within each category (smile, frown or neutral. Ranks within categories were then combined to obtain a rank ordering for all the test samples. Results The ranking from best to worst for the samples across categories (UHT, powder, evaporated was xylitol (0.0.042 g/ml, sorbitol (0.042 g/ml, xylitol (0.021 g/ml and milk alone (Friedman's ANOVA. Xylitol and sorbitol were preferred over milk alone, and xylitol (0.042 g/ml was preferred to sorbitol (0.042 g/ml(p Conclusion Milk sweetened with xylitol is well accepted by Peruvian children ages 4–7 years.

The type III secretion system is involved in the invasion and intracellular survival of Escherichia coli K1 in human brain microvascular endothelial cells

OpenAIRE

Yao, Yufeng; Xie, Yi; Perace, Donna; Zhong, Yi; Lu, Jie; Tao, Jing; Guo, Xiaokui; Kim, Kwang Sik

2009-01-01

Type III secretion systems have been documented in many Gram-negative bacteria, including enterohemorrhagic Escherichia coli. We have previously shown the existence of a putative type III secretion system in meningitis-causing E. coli K1 strains, referred to as E. coli type III secretion 2 (ETT2). The sequence of ETT2 in meningitis-causing E. coli K1 strain EC10 (O7:K1) revealed that ETT2 comprises the epr, epa and eiv genes, but bears mutations, deletions and insertions. We constructed the E...

Increased sorbitol levels in the hypertrophic ligamentum flavum of diabetic patients with lumbar spinal canal stenosis.

Science.gov (United States)

Luo, Jiaquan; Huang, Lu; Chen, Zhuo; Zeng, Zhaoxun; Miyamoto, Takeshi; Wu, Hao; Zhang, Zhongzu; Pan, Zhimin; Fujita, Nobuyuki; Hikata, Tomohiro; Iwanami, Akio; Tsuji, Takashi; Ishii, Ken; Nakamura, Masaya; Matsumoto, Morio; Watanabe, Kota; Cao, Kai

2017-05-01

The pathomechanism of the ligamentum flavum (LF) hypertrophy in diabetic patients with lumbar spinal canal stenosis (LSCS) remains unclear. A cross-sectional study was undertaken to investigate the mechanism of LF hypertrophy in these patients. Twenty-four diabetic and 20 normoglycemic patients with LSCS were enrolled in the study. The structure of the LF in the study subjects was evaluated using histological and immunohistochemical methods, and the levels of sorbitol, pro-inflammatory cytokines, and the fibrogenic factor, TGF-β1, in the LF were analyzed. In vitro experiments were performed using NIH3T3 fibroblasts to evaluate the effect of high-glucose conditions and an aldose reductase inhibitor on the cellular production of sorbitol, pro-inflammatory factors, and TGF-β1. We found that the LF of diabetic patients exhibited significantly higher levels of sorbitol and pro-inflammatory cytokines, TGF-β1 and of CD68-positive staining than that of the normoglycemic subjects. The diabetic LF was significantly thicker than that of the controls, and showed evidence of degeneration. The high glucose-cultured fibroblasts exhibited significantly higher levels of sorbitol, pro-inflammatory factors, and TGF-β1 compared to the low glucose-cultured cells, and these levels were dose-dependently reduced by treatment with the aldose reductase inhibitor. Taken together, our data suggests that increased sorbitol levels in the LF of diabetic patients results in increased production of pro-inflammatory and fibrogenic factor, which contribute to LF hypertrophy, and could increase the susceptibility of diabetic patients to LSCS. Furthermore, aldose reductase inhibition effectively reduced the levels of sorbitol and sorbitol-induced pro-inflammatory factor expression in high glucose-cultured fibroblasts. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1058-1066, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

DEFF Research Database (Denmark)

Yennawar, Hemant; Møller, Magda; Gillilan, Richard

2011-01-01

The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer...

Effect of selected aldehydes on the growth and fermentation of ethanologenic Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Zaldivar, J.; Ingram, L.O. [Univ. of Florida, Gainesville (United States). Dept. of Microbiology and Cell Science; Martinez, A. [Univ. of Florida, Gainesville (United States). Dept. of Microbiology and Cell Science]|[Univ. Nacional Autonoma de Mexico (Mexico). Inst. de Biotecnologia

1999-10-05

Bioethanol production from lignocellulosic raw-materials requires the hydrolysis of carbohydrate polymers into a fermentable syrup. During the hydrolysis of hemicellulose with dilute acid, a variety of toxic compounds are produced such as soluble aromatic aldehydes from lignin and furfural from pentose destruction. In this study, the authors have investigated the toxicity of representative aldehydes (furfural, 5-hydroxymethlyfurfural, 4-hydroxybenzaldehyde, syringaldehyde, and vanillin) as inhibitors of growth and ethanol production by ethanologenic derivatives of Escherichia coli B (strains K011 and LY01). Aromatic aldyhydes were at least twice as toxic as furfural of 5-hydroxymethylfurfural on a weight basis. The toxicities of all aldehydes (and ethanol) except furfural were additive when tested in binary combinations. In all cases, combinations with furfural were unexpectedly toxic. Although the potency of these aldehydes was directly related to hydrophobicity indicating a hydrophobic site of action, none caused sufficient membrane damage to allow the leakage of intracellular magnesium even when present at sixfold the concentrations required for growth inhibition. Of the aldehydes tested, only furfural strongly inhibited ethanol production in vitro. A comparison with published results for other microorganisms indicates that LY01 is equivalent or more resistant than other biocatalysts to the aldehydes examined in this study.

Efeito da sacarose e sorbitol na conservação in vitro de Passiflora giberti N. E. Brown Sucrose and sorbitol effect in the in vitro conservation of Passiflora giberti N. E. Brown

Directory of Open Access Journals (Sweden)

Gláucia Amorim Faria

2006-08-01

Full Text Available Este trabalho teve como objetivo estudar o efeito da sacarose e do sorbitol na conservação in vitro de um acesso de Passiflora giberti N. E. Brown. Para isso, foi instalado um experimento no delineamento inteiramente casualizado, em que foi comparado o tratamento-testemunha (MS padrão com o meio MS suplementado com três concentrações de sacarose (0; 15 e 30 g L-1 em combinação com três concentrações de sorbitol (10; 20 e 40 g L-1. As avaliações foram realizadas aos 30; 60; 90 e 120 dias de incubação, observando-se o comprimento das brotações (cm, número de raízes, número e coloração das folhas. Os resultados mostram ser possível conservar sob crescimento lento, por quatro meses, microplantas de maracujazeiro em meio de cultura MS suplementado com 10 ou 20 g L-1 de sorbitol, na ausência de sacarose, e mantidas sob condições de fotoperíodo de 16 h (22 µE m-2s-1 e temperatura de 27 ± 1 ºC. A sacarose promoveu maior desenvolvimento de microplantas. A rizogênese é afetada pelo sorbitol na concentração de 40 g L-1 e pela ausência de sacarose no meio de cultura.This work objectified the study of sucrose and sorbitol effect in the in vitro conservation for Passiflora giberti N. E. Brown, access. Therefore, an experiment was conducted in a completely randomized design to compare control treatment (standard MS to MS medium supplemented with three sucrose concentrations (0, 15 and 30 g L-1 combined with three sorbitol concentrations (10, 20 and 40 g L-1, in a total of 10 treatments with 20 replicas. The experiment evaluation was carried out at 30, 60, 90 and 120 days of incubation, whereas the height of shoots (cm, number of roots, number and color of leaves were observed. The results showed the possibility to maintain passion-fruit microplants for a four months period under slow growth in MS medium supplemented with 10 or 20 g L-1 of sorbitol, without sucrose, and kept under 16 hours photoperiod (22 µ E m-2 s-1 and

Suppressing Sorbitol Synthesis Substantially Alters the Global Expression Profile of Stress Response Genes in Apple (Malus domestica) Leaves.

Science.gov (United States)

Wu, Ting; Wang, Yi; Zheng, Yi; Fei, Zhangjun; Dandekar, Abhaya M; Xu, Kenong; Han, Zhenhai; Cheng, Lailiang

2015-09-01

Sorbitol is a major product of photosynthesis in apple (Malus domestica) that is involved in carbohydrate metabolism and stress tolerance. However, little is known about how the global transcript levels in apple leaves respond to decreased sorbitol synthesis. In this study we used RNA sequencing (RNA-seq) profiling to characterize the transcriptome of leaves from transgenic lines of the apple cultivar 'Greensleeves' exhibiting suppressed expression of aldose-6-phosphate reductase (A6PR) to gain insights into sorbitol function and the consequences of decreased sorbitol synthesis on gene expression. We observed that, although the leaves of the low sorbitol transgenic lines accumulate higher levels of various primary metabolites, only very limited changes were found in the levels of transcripts associated with primary metabolism. We suggest that this is indicative of post-transcriptional and/or post-translational regulation of primary metabolite accumulation and central carbon metabolism. However, we identified significantly enriched gene ontology terms belonging to the 'stress related process' category in the antisense lines (P-value sorbitol plays a role in the responses of apple trees to abiotic and biotic stresses. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Differential response of nucleus pulposus intervertebral disc cells to high salt, sorbitol, and urea.

Science.gov (United States)

Mavrogonatou, Eleni; Kletsas, Dimitris

2012-03-01

Nucleus pulposus intervertebral disc cells are routinely confronted with high osmolality in their microenvironment and respond to this stress in vitro by regulating cell cycle progression and by activating a DNA repair machinery in order to counteract its genotoxic effect. In the present study, we attempted to identify the origin of this osmo-regulatory response, by using an ionic NaCl/KCl solution, the compatible osmolyte sorbitol, and the readily permeant urea. High salt and sorbitol were found to activate similar molecular pathways, including the p38 MAPK and the p53-p21(WAF1)-pRb axis, that were not stimulated by high urea. On the other hand, only high urea led to the phosphorylation of ERKs and JNKs. Furthermore, salt- and sorbitol-treated cells were able to phosphorylate histone H2A.X on Ser139, in contrast to cells exposed to urea, indicating a common mechanism for DNA repair, which was achieved by a p53-dependent activation of the G1 checkpoint by both solutes. DNA repair, as directly measured by a host cell reactivation assay, occurred under conditions of hyperosmolar salt and sorbitol, although to a lesser extent in sorbitol-treated cells than in cells exposed to high salinity. Taken as a whole, our findings suggest that the hyperosmolality-provoked DNA damage and the responses of nucleus pulposus cells induced by this genotoxic stress most probably originate from cell volume alterations mediated by hypertonicity and not from increased intracellular ionic concentration. Copyright © 2011 Wiley Periodicals, Inc.

Optimization of asparaginase production from Zymomonas mobilis by continuous fermentation

Directory of Open Access Journals (Sweden)

Francieli Bortoluzzi Menegat

2016-10-01

Full Text Available Asparaginase is an enzyme used in clinical treatments as a chemotherapeutic agent and in food technology to prevent acrylamide formation in fried and baked foods. Asparaginase is industrially produced by microorganisms, mainly gram-negative bacteria. Zymomonas mobilis is a Gram-negative bacterium that utilizes glucose, fructose and sucrose as carbon source and has been known for its efficiency in producing ethanol, sorbitol, levan, gluconic acid and has recently aroused interest for asparaginase production. Current assay optimizes the production of Z. mobilis asparaginase by continuous fermentation using response surface experimental design and methodology. The studied variables comprised sucrose, yeast extract and asparagine. Optimized condition obtained 117.45 IU L-1 with dilution rate 0.20 h-1, yeast extract 0.5 g L-1, sucrose 20 g L-1 and asparagine 1.3 g L-1. Moreover, carbon:nitrogen ratio (1:0.025 strongly affected the response of asparaginase activity. The use of Z. mobilis by continuous fermentation has proved to be a promising alternative for the biotechnological production of asparaginase.

Dietary sorbitol and mannitol: food content and distinct absorption patterns between healthy individuals and patients with irritable bowel syndrome.

Science.gov (United States)

Yao, C K; Tan, H-L; van Langenberg, D R; Barrett, J S; Rose, R; Liels, K; Gibson, P R; Muir, J G

2014-04-01

Sorbitol and mannitol are naturally-occurring polyol isomers. Although poor absorption and induction of gastrointestinal symptoms by sorbitol are known, the properties of mannitol are poorly described. We aimed to expand data on food composition of these polyols, and to compare their absorptive capacities and symptom induction in patients with irritable bowel syndrome (IBS) and healthy individuals. Food samples were analysed for sorbitol and mannitol content. The degree of absorption measured by breath hydrogen production and gastrointestinal symptoms (visual analogue scales) was evaluated in a randomised, double-blinded, placebo-controlled study in 21 healthy and 20 IBS subjects after challenges with 10 g of sorbitol, mannitol or glucose. Certain fruits and sugar-free gum contained sorbitol, whereas mannitol content was higher in certain vegetables. Similar proportions of patients with IBS (40%) and healthy subjects (33%) completely absorbed sorbitol, although more so with IBS absorbed mannitol (80% versus 43%; P = 0.02). Breath hydrogen production was similar in both groups after lactulose but was reduced in patients with IBS after both polyols. No difference in mean (SEM) hydrogen production was found in healthy controls after sorbitol [area-under-the-curve: 2766 (591) ppm 4 h(-1) ] or mannitol [2062 (468) ppm 4 h(-1) ] but, in patients with IBS, this was greater after sorbitol [1136 (204) ppm 4 h(-1) ] than mannitol [404 (154) ppm 4 h(-1) ; P = 0.002]. Overall gastrointestinal symptoms increased significantly after both polyols in patients with IBS only, although they were independent of malabsorption of either of the polyols. Increased and discordant absorption of mannitol and sorbitol occurs in patients with IBS compared to that in healthy controls. Polyols induced gastrointestinal symptoms in patients with IBS independently of their absorptive patterns, suggesting that the dietary restriction of polyols may be efficacious. © 2013 The

Ordered Mesoporous NiCeAl Containing Catalysts for Hydrogenolysis of Sorbitol to Glycols

Science.gov (United States)

Zhou, Zhiwei; Zhang, Jiaqi; Qin, Juan; Li, Dong; Wu, Wenliang

2018-03-01

Cellulose-derived sorbitol is emerging as a feasible and renewable feedstock for the production of value-added chemicals. Highly active and stable catalyst is essential for sorbitol hydrogenolysis. Ordered mesoporous M- xNi yCeAl catalysts with different loadings of nickel and cerium species were successfully synthesized via one-pot evaporation-induced self-assembly strategy (EISA) and their catalytic performance were tested in the hydrogenolysis of sorbitol. The physical chemical properties for the catalysts were characterized by XRD, N2 physisorption, H2-TPR, H2 impulse chemisorption, ICP and TEM techniques. The results showed that the ordered mesopores with uniform pore sizes can be obtained and the Ni nanoparticles around 6 nm in size were homogeneously dispersed in the mesopore channels. A little amount of cerium species introduced would be beneficial to their textural properties resulting in higher Ni dispersion, metal area and smaller size of Ni nanoparticles. The M-10Ni2CeAl catalyst with Ni and Ce loading of 10.9 and 6.3 wt % shows better catalytic performance than other catalysts, and the yield of 1,2-PG and EG can reach 56.9% at 493 K and 6 MPa pressure for 8 h after repeating reactions for 12 times without obvious deterioration of physical and chemical properties. Ordered mesoporous M-NiCeAl catalysts are active and stable in sorbitol hydrogenolysis.

Advanced glycation end products and sorbitol in blood from differently compensated diabetic dogs.

Science.gov (United States)

Comazzi, S; Bertazzolo, W; Bonfanti, U; Spagnolo, V; Sartorelli, P

2008-06-01

Canine diabetes mellitus (DM) is a common metabolic disorder with long term complications, most of which are caused by glycosylation of structural proteins, decreases in antioxidant concentrations, altered osmotic balance and hypoxia due to impaired oxygen transport. Previous studies have demonstrated that under hyperglycemic conditions canine erythrocytes undergo swelling, probably due to activation of the polyol pathway. The present work aimed to assess the plasma concentration of advanced glycation end (AGE) products, stable Amadori-products generated by non-enzymatic glycosylation of proteins and the intracellular concentration of sorbitol, produced by the activation of polyol pathway in 34 blood samples from diabetic dogs and in 14 controls. AGE products were significantly higher (pdogs compared with control animals. The sorbitol concentration in erythrocytes was also significantly higher in diabetic dogs and, in particular, in poorly compensated animals and in dogs with ketonuria. In five cases that were analysed before and after clinical improvement, sorbitol concentration was found to correlate with improvement. These results suggest that non-specific glycosylation is increased and that the polyol pathway is activated in diabetic dogs in a manner that is proportionate to the severity of disease. Moreover, the concentration of AGE products and sorbitol may be useful for monitoring the onset of diabetic complications and assessing the most appropriate therapeutic approaches for management of canine DM.

Thin layer chromatography of glucose and sorbitol on Cu(II)-impregnated silica gel plates

Energy Technology Data Exchange (ETDEWEB)

Hadzija, O. (Ruder Boskovic Inst., Zagreb (Croatia)); Spoljar, B. (Ruder Boskovic Inst., Zagreb (Croatia)); Sesartic, L. (Inst. of Immunology, Zagreb (Croatia))

1994-04-01

A thin-layer chromatographic (TLC) separation of glucose and sorbitol on CU(II)-impregnated silica gel plates with n-propanol: Water (4:1) v/v as developer and potassium permanganate as detecting reagent has been worked out. The new impregnant is completely insoluble in water and thus enables the use of an aqueous developer. The R[sub f]-values are 55 and 10 for glucose and sorbitol, respectively. (orig.)

D-sorbitol-induced phase control of TiO2 nanoparticles and its application for dye-sensitized solar cells

Science.gov (United States)

Shaikh, Shoyebmohamad F.; Mane, Rajaram S.; Min, Byoung Koun; Hwang, Yun Jeong; Joo, Oh-Shim

2016-02-01

Using a simple hydrothermal synthesis, the crystal structure of TiO2 nanoparticles was controlled from rutile to anatase using a sugar alcohol, D-sorbitol. Adding small amounts of D-sorbitol to an aqueous TiCl4 solution resulted in changes in the crystal phase, particle size, and surface area by affecting the hydrolysis rate of TiCl4. These changes led to improvements of the solar-to-electrical power conversion efficiency (η) of dye-sensitized solar cells (DSSC) fabricated using these nanoparticles. A postulated reaction mechanism concerning the role of D-sorbitol in the formation of rutile and anatase was proposed. Fourier-transform infrared spectroscopy, 13C NMR spectroscopy, and dynamic light scattering analyses were used to better understand the interaction between the Ti precursor and D-sorbitol. The crystal phase and size of the synthesized TiO2 nanocrystallites as well as photovoltaic performance of the DSSC were examined using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and photocurrent density-applied voltage spectroscopy measurement techniques. The DSSC fabricated using the anatase TiO2 nanoparticles synthesized in the presence of D-sorbitol, exhibited an enhanced η (6%, 1.5-fold improvement) compared with the device fabricated using the rutile TiO2 synthesized without D-sorbitol.

Development of selective and differential medium for Shigella sonnei using three carbohydrates (lactose, sorbitol, and xylose) and X-Gal.

Science.gov (United States)

Na, G N; Kim, S A; Kwon, O C; Rhee, M S

2015-08-01

The aim of this study was to develop a new selective and differential medium for isolating Shigella sonnei (designated 3SD medium). The new medium was based on three carbohydrates (lactose, sorbitol, and xylose) and a chromogenic substrate (5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside, X-Gal). S. sonnei cannot ferment lactose, sorbitol, or xylose, but can ferment X-Gal, which generates turquoise-blue colonies with rough edges. Other bacteria (54 strains of foodborne pathogens and spoilage bacteria) produced visually distinct colonies on 3SD medium (colorless or pink-violet colonies), or their growth was inhibited on 3SD medium. The optimum concentration of 50 mg/L X-Gal was selected because it yielded the highest level of morphological discrimination between S. sonnei and other bacteria, and this concentration was cost-effective. Bile salt concentration optimization was performed using healthy, heat-injured, and acid-injured S. sonnei. The recovery rate differed significantly depending on the bile salt concentration; media containing >1.0 g/L bile salt showed significantly lower recovery of stress-injured cells than medium containing 0.5 g/L bile salt (P<0.05). Growth of all Gram-positive bacteria was inhibited on medium containing 0.5 g/L bile salt; therefore, this concentration was used as the optimal concentration. Previous media used to isolate Shigella spp. (MacConkey, xylose lysine desoxycholate, and Salmonella-Shigella agar) showed poor performance when used to support the growth of injured S. sonnei cells, whereas 3SD medium supported a high growth rate of injured and healthy cells (equivalent to that obtained with nutrient-rich tryptic soy agar). To validate the performance of 3SD medium with real specimens, S. sonnei and other bacteria were spiked into samples such as untreated water, carrot, salad, and oyster. 3SD medium showed superior specificity (100%) and sensitivity (100%) for S. sonnei, and yielded no false-positive or false-negative results

Reconstruction of a metabolic regulatory network in Escherichia coli for purposeful switching from cell growth mode to production mode in direct GABA fermentation from glucose.

Science.gov (United States)

Soma, Yuki; Fujiwara, Yuri; Nakagawa, Takuya; Tsuruno, Keigo; Hanai, Taizo

2017-09-01

γ-aminobutyric acid (GABA) is a drug and functional food additive and is used as a monomer for producing the biodegradable plastic, polyamide 4. Recently, direct GABA fermentation from glucose has been developed as an alternative to glutamate-based whole cell bioconversion. Although total productivity in fermentation is determined by the specific productivity and cell amount responsible for GABA production, the optimal metabolic state for GABA production conflicts with that for bacterial cell growth. Herein, we demonstrated metabolic state switching from the cell growth mode based on the metabolic pathways of the wild type strain to a GABA production mode based on a synthetic metabolic pathway in Escherichia coli through rewriting of the metabolic regulatory network and pathway engineering. The GABA production mode was achieved by multiple strategies such as conditional interruption of the TCA and glyoxylate cycles, engineering of GABA production pathway including a bypass for precursor metabolite supply, and upregulation of GABA transporter. As a result, we achieved 3-fold improvement in total GABA production titer and yield (4.8g/L, 49.2% (mol/mol glucose)) in batch fermentation compared to the case without metabolic state switching (1.6g/L, 16.4% (mol/mol glucose)). This study reports the highest GABA production performance among previous reports on GABA fermentation from glucose using engineered E. coli. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

Energy Technology Data Exchange (ETDEWEB)

Dr. David Nunn

2010-09-30

The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.

Sorbitol increases muscle glucose uptake ex vivo and inhibits intestinal glucose absorption ex vivo and in normal and type 2 diabetic rats.

Science.gov (United States)

Chukwuma, Chika Ifeanyi; Islam, Md Shahidul

2017-04-01

Previous studies have suggested that sorbitol, a known polyol sweetener, possesses glycemic control potentials. However, the effect of sorbitol on intestinal glucose absorption and muscle glucose uptake still remains elusive. The present study investigated the effects of sorbitol on intestinal glucose absorption and muscle glucose uptake as possible anti-hyperglycemic or glycemic control potentials using ex vivo and in vivo experimental models. Sorbitol (2.5% to 20%) inhibited glucose absorption in isolated rat jejuna (IC 50 = 14.6% ± 4.6%) and increased glucose uptake in isolated rat psoas muscle with (GU 50 = 3.5% ± 1.6%) or without insulin (GU 50 = 7.0% ± 0.5%) in a concentration-dependent manner. Furthermore, sorbitol significantly delayed gastric emptying, accelerated digesta transit, inhibited intestinal glucose absorption, and reduced blood glucose increase in both normoglycemic and type 2 diabetic rats after 1 h of coingestion with glucose. Data of this study suggest that sorbitol exhibited anti-hyperglycemic potentials, possibly via increasing muscle glucose uptake ex vivo and reducing intestinal glucose absorption in normal and type 2 diabetic rats. Hence, sorbitol may be further investigated as a possible anti-hyperglycemic sweetener.

Activation of sorbitol pathway in metabolic syndrome and increased susceptibility to cataract in Wistar-Obese rats.

Science.gov (United States)

Reddy, Paduru Yadagiri; Giridharan, Nappan Veettil; Reddy, Geereddy Bhanuprakash

2012-01-01

Obesity is a major public health problem worldwide, and of late, epidemiological studies indicate a preponderance of cataracts under obesity conditions. Although cataract is a multifactorial disorder and various biochemical mechanisms have been proposed, the influence of obesity on cataractogenesis has yet to be investigated. In such a scenario, a suitable animal model that develops cataract following the onset of obesity will be a welcome tool for biomedical research. Therefore, we investigated the molecular and biochemical basis for predisposition to cataract in the obese mutant rat models established in our institute because 15%-20% of these rats develop cataracts spontaneously as they reach 12-15 months of age. We analyzed the major biochemical pathways in the normal lenses of different age groups of our obese mutant rat strains, Wistar/Obese (WNIN/Ob) and WNIN/GR-Ob, the former with euglycemia and the latter with an additional impaired glucose tolerance trait. In addition, sorbitol levels were estimated in the cataractous lenses of the obese rats. Except for the polyol pathway, all the principal pathways of the lens remained unaltered. Therefore, sorbitol levels were found to be high in the normal eye lenses of obese rats (WNIN/Ob and WNIN/GR-Ob) compared to their lean controls from three months of age onwards. Between WNIN/Ob and WNIN/GR-Ob, the levels of sorbitol were higher in the latter, suggesting a synergistic effect of impaired glucose tolerance along with obesity in the activation of the sorbitol pathway. Either way, an elevated sorbitol pathway seemed to be the predisposing factor responsible for cataract formation in these mutant rats. Activation of the sorbitol pathway indeed enhances the risk of cataract development in conditions such as metabolic syndrome. These rat models thus may be valuable tools for investigating obesity-associated cataract and for developing intervention strategies, based on these findings.

Putative metabolic pathway of mannitol and sorbitol and in sugarcane Provável via metabólica de manitol e sorbitol em cana-de-açúcar

Directory of Open Access Journals (Sweden)

Celso Luís Marino

2003-12-01

Full Text Available Until the mid 1950s, boron was believed to play an important role in the transport of sugars in plants. However, boron actually depends on sugar alcohols to be taken up by the plant. In some cases, the main sugars involved in this process are sorbitol and mannitol which form stable complexes with boron. In this study, the sequences of the SugarCane EST Genome Project (SUCEST database were searched for enzymes involved in the metabolism of these sugars by comparing them with enzymes from other organisms. Eighteen contigs from sugarcane (Saccharum sp. presented high similarity with 11 enzymes involved in the putative biosynthetic pathway of sorbitol and mannitol from fructose in sugarcane. Seven of these contigs had high homology with sequences deposited in GenBank.Até meados da década de 50 acreditava-se que o boro tinha uma importante função no transporte de açúcares em plantas. Na verdade, o boro depende de açúcares álcoois para serem mobilizados dentro da planta. Em alguns organismos os principais açúcares envolvidos neste processo são o sorbitol e o manitol, que formam complexos estáveis com o micronutriente. O objetivo deste estudo foi procurar seqüências no banco de dados SugarCane EST Genome Project (SUCEST que codificam enzimas participantes na via metabólica destes açúcares através da comparação de enzimas de outros organismos. Dezoito "contigs" de cana-de-açúcar (Saccharum sp. apresentaram similaridade com onze seqüências de enzimas que compõem a provável via metabólica de sorbitol e manitol a partir de frutose. Destes "contigs", sete apresentaram uma alta similaridade entre as seqüências depositadas no GenBank.

Magnetic study of iron sorbitol

Energy Technology Data Exchange (ETDEWEB)

Lazaro, F.J. E-mail: osoro@posta.unizar.es; Larrea, A.; Abadia, A.R.; Romero, M.S

2002-09-01

A magnetic study of iron sorbitol, an iron-containing drug to treat the iron deficiency anemia is presented. Transmission electron microscopy reveals that the system contains nanometric particles with an average diameter of 3 nm whose composition is close to two-line ferrihydrite. The characterisation by magnetisation and AC susceptibility measurements indicates superparamagnetic behaviour with progressive magnetic blocking starting at 8 K. The quantitative analysis of the magnetic results indicates that the system consists of an assembly of very small magnetic moments, presumably originated by spin uncompensation of the antiferromagnetic nanoparticles, with Arrhenius type magnetic dynamics.

Increased risk of cataract development in WNIN-obese rats due to accumulation of intralenticular sorbitol.

Science.gov (United States)

Reddy, Paduru Yadagiri; Giridharan, Nappan Veettil; Balakrishna, Nagalla; Validandi, Vakdevi; Pullakhandam, Raghu; Reddy, Geereddy Bhanuprakash

2013-05-01

Epidemiological studies have reported an association between obesity and increased incidence of ocular complications including cataract, yet the underlying biochemical and molecular mechanisms remained unclear. Previously we had demonstrated accumulation of sorbitol in the lens of obese rats (WNIN/Ob) and more so in a related strain with impaired glucose tolerance (WNIN/GR-Ob). However, only a few (15-20%) WNIN/Ob and WNIN/GR-Ob rats develop cataracts spontaneously with age. To gain further insights, we investigated the susceptibility of eye lens proteins of these obese rat strains to heat- and UV-induced aggregation in vitro, lens opacification upon glucose-mediated sorbitol accumulation ex vivo, and onset and progression of cataract was followed by galactose feeding and streptozotocin (STZ) injection. The results indicated increased susceptibility toward heat- or UV-induced aggregation of lens proteins in obese animals compared to their littermate lean controls. Further, in organ culture studies glucose-induced sorbitol accumulation was found to be higher and thus the lens opacification was faster in obese animals compared to their lean littermates. Also, the onset and progression of galactose- or STZ-induced cataractogenesis was faster in obese animals compared to lean control. These results together with our previous observations suggest that obesity status could lead to hyperaccumulation of sorbitol in eye lens, predisposing them to cataract, primarily by increasing their susceptibility to environmental and/or physiological factors. Further, intralenticular sorbitol accumulation beyond a threshold level could lead to cataract in WNIN/Ob and WNIN/GR-Ob rats. Copyright © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Simultaneous catalytic conversion of cellulose and corncob xylan under temperature programming for enhanced sorbitol and xylitol production.

Science.gov (United States)

Ribeiro, Lucília Sousa; Órfão, José J de Melo; Pereira, Manuel Fernando Ribeiro

2017-11-01

Sorbitol and xylitol yields can be improved by converting cellulose and xylan simultaneously, due to a synergetic effect between both substrates. Furthermore, both yields can be greatly enhanced by simply adjusting the reaction conditions regarding the optimum for the production of each product, since xylitol (from xylan) and sorbitol (from cellulose) yields are maximized when the reaction is carried out at 170 and 205°C, respectively. Therefore, the combination of a simultaneous conversion of cellulose and xylan with a two-step temperature approach, which consists in the variation of the reaction temperature from 170 to 205°C after 2h, showed to be a good strategy for maximizing the production of sorbitol and xylitol directly from mixture of cellulose and xylan. Using this new and environmentally friendly approach, yields of sorbitol and xylitol of 75 and 77%, respectively, were obtained after 6h of reaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vancomycin-resistant Enterococcus faecium bacteraemia as a complication of Kayexalate (sodium polystyrene sulfonate, SPS) in sorbitol-induced ischaemic colitis.

Science.gov (United States)

Cerrud-Rodriguez, Roberto Christian; Alcaraz-Alvarez, Diego; Chiong, Brian Bobby; Ahmed, Abdurhman

2017-11-09

We present the case report of an 80-year-old woman with chronic kidney disease stage G5 admitted to the hospital with fluid overload and hyperkalaemia. Sodium polystyrene sulfonate (SPS, Kayexalate) in sorbitol suspension was given orally to treat her hyperkalaemia, which precipitated an episode of SPS in sorbitol-induced ischaemic colitis with the subsequent complication of vancomycin-resistant Enterococcus (VRE) bacteraemia. SPS (Kayexalate) in sorbitol suspension has been implicated in the development of intestinal necrosis. Sorbitol, which is added as a cathartic agent to decrease the chance of faecal impaction, may be primarily responsible through several proposed mechanisms. The gold standard of diagnosis is the presence of SPS crystals in the colon biopsy. On a MEDLINE search, no previous reports of a VRE bacteraemia as a complication of biopsy-confirmed SPS in sorbitol ischaemic colitis were found. To the best of our knowledge, ours would be the first such case ever reported. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

FORMULA OPTIMATION OF SENGGUGU ROOT BARK EXTRACT LOZENGES (Clerodendrum serratum (L. Moon. AS MUCOLYTIC AGENT WITH LACTOSE – SORBITOL FILLER COMBINATION

Directory of Open Access Journals (Sweden)

Wahyono Wahyono

2015-11-01

Full Text Available Senggugu root bark has mucolytic activity and has been used empirically, so it needs to be formulated as lozengeswhich can be used practically and comfortable for the patients. Senggugu root bark powder was extracted by maceration using aethanol 70%. Lozenges was optimized using lactose-sorbitol filler mix through three formulas, formula A ( 100% lactose, formula B (100% sorbitol, formula C (50% lactose-50% sorbitol. Lozenges was made by wet granulation method. The optimum formula was obtained from theresults of physical granul test and lozenges using SLD, and analyzed by its granul flow, hardness, dissolution time, and taste responsiveness, and also qualitative and quantitative analysis. The results show that lactose-sorbitol filler mix can increase hardness and taste responsiveness, decrease granul flow and dissolution time. The oprimum formula from this research is 100% sorbitol:0% lactose.

Development of a promoter shutoff system in Aspergillus oryzae using a sorbitol-sensitive promoter.

Science.gov (United States)

Oda, Ken; Terado, Shiho; Toyoura, Rieko; Fukuda, Hisashi; Kawauchi, Moriyuki; Iwashita, Kazuhiro

2016-09-01

Promoter shutoff is a general method for analyzing essential genes, but in the fungus Aspergillus oryzae, no tightly repressed promoters have been reported. To overcome the current limitations of conditional promoters, we examined sorbitol- and galactose-responsive genes using microarrays to identify regulatable genes with only minor physiological and genetic effects. We identified two sorbitol-induced genes (designated as sorA and sorB), cloned their promoters, and built a regulated egfp and brlA expression system. Growth medium-dependent enhanced green fluorescence protein (EGFP) fluorescence and conidiation were confirmed for egfp and brlA under the control of their respective promoters. We also used this shutoff system to regulate the essential rhoA, which demonstrated the expected growth inhibition under repressed growth conditions. Our new sorbitol promoter shutoff system developed can serve as a valuable new tool for essential gene analyses of filamentous fungi.

Pronounced microheterogeneity in a sorbitol-water mixture observed through variable temperature neutron scattering.

Science.gov (United States)

Chou, Shin G; Soper, Alan K; Khodadadi, Sheila; Curtis, Joseph E; Krueger, Susan; Cicerone, Marcus T; Fitch, Andrew N; Shalaev, Evgenyi Y

2012-04-19

In this study, the structure of concentrated d-sorbitol-water mixtures is studied by wide- and small-angle neutron scattering (WANS and SANS) as a function of temperature. The mixtures are prepared using both deuterated and regular sorbitol and water at a molar fraction of sorbitol of 0.19 (equivalent to 70% by weight of regular sorbitol in water). Retention of an amorphous structure (i.e., absence of crystallinity) is confirmed for this system over the entire temperature range, 100-298 K. The glass transition temperature, Tg, is found from differential scanning calorimetry to be approximately 200 K. WANS data are analyzed using empirical potential structure refinement, to obtain the site-site radial distribution functions (RDFs) and coordination numbers. This analysis reveals the presence of nanoscaled water clusters surrounded by (and interacting with) sorbitol molecules. The water clusters appear more structured compared to bulk water and, especially at the lowest temperatures, resemble the structure of low-density amorphous ice (LDA). Upon cooling to 100 K the peaks in the water RDFs become markedly sharper, with increased coordination number, indicating enhanced local (nanometer-scale) ordering, with changes taking place both above and well below the Tg. On the mesoscopic (submicrometer) scale, although there are no changes between 298 and 213 K, cooling the sample to 100 K results in a significant increase in the SANS signal, which is indicative of pronounced inhomogeneities. This increase in the scattering is partly reversed during heating, although some hysteresis is observed. Furthermore, a power law analysis of the SANS data indicates the existence of domains with well-defined interfaces on the submicrometer length scale, probably as a result of the appearance and growth of microscopic voids in the glassy matrix. Because of the unusual combination of small and wide scattering data used here, the present results provide new physical insight into the

Effect of xylitol versus sorbitol: a quantitative systematic review of clinical trials.

Science.gov (United States)

Mickenautsch, Steffen; Yengopal, Veerasamy

2012-08-01

This study aimed to appraise, within the context of tooth caries, the current clinical evidence and its risk for bias regarding the effects of xylitol in comparison with sorbitol. Databases were searched for clinical trials to 19 March 2011. Inclusion criteria required studies to: test a caries-related primary outcome; compare the effects of xylitol with those of sorbitol; describe a clinical trial with two or more arms, and utilise a prospective study design. Articles were excluded if they did not report computable data or did not follow up test and control groups in the same way. Individual dichotomous and continuous datasets were extracted from accepted articles. Selection and performance/detection bias were assessed. Sensitivity analysis was used to investigate attrition bias. Egger's regression and funnel plotting were used to investigate risk for publication bias. Nine articles were identified. Of these, eight were accepted and one was excluded. Ten continuous and eight dichotomous datasets were extracted. Because of high clinical heterogeneity, no meta-analysis was performed. Most of the datasets favoured xylitol, but this was not consistent. The accepted trials may be limited by selection bias. Results of the sensitivity analysis indicate a high risk for attrition bias. The funnel plot and Egger's regression results suggest a low publication bias risk. External fluoride exposure and stimulated saliva flow may have confounded the measured anticariogenic effect of xylitol. The evidence identified in support of xylitol over sorbitol is contradictory, is at high risk for selection and attrition bias and may be limited by confounder effects. Future high-quality randomised controlled trials are needed to show whether xylitol has a greater anticariogenic effect than sorbitol. © 2012 FDI World Dental Federation.

Cryopreservation of boar semen by egg yolk-based extenders containing lactose or fructose is better than sorbitol.

Science.gov (United States)

Chanapiwat, Panida; Kaeoket, Kampon; Tummaruk, Padet

2012-03-01

The present study determined the effect of different types of sugars (lactose, fructose, glucose and sorbitol) used in egg yolk-based extender on the post-thawed boar semen quality. Twenty-two ejaculates from 6 fertility-proven Yorkshire boars were cryopreserved by liquid nitrogen vapor method. Sperm motility, viability, acrosome integrity and intact functional plasma membrane were determined at 0, 2 and 4 hr after thawing. It was found that the lactose-based extender resulted in a higher percentage of post-thawed sperm motility, viability, intact acrosome and functional plasma membrane than sorbitol-based extender (Pextender yielded a higher post-thawed sperm motility and viability than sorbitol-based extender (Pboar semen.

Mechanosensing regulates virulence in Escherichia coli O157:H7.

Science.gov (United States)

Islam, Md Shahidul; Krachler, Anne Marie

2016-01-01

Enterohemorrhagic Escherichia coli O157:H7 is a food-borne pathogen transmitted via the fecal-oral route, and can cause bloody diarrhea and hemolytic uremic syndrome (HUS) in the human host. Although a range of colonization factors, Shiga toxins and a type III secretion system (T3SS) all contribute to disease development, the locus of enterocyte effacement (LEE) encoded T3SS is responsible for the formation of lesions in the intestinal tract. While a variety of chemical cues in the host environment are known to up-regulate LEE expression, we recently demonstrated that changes in physical forces at the site of attachment are required for localized, full induction of the system and thus spatial regulation of virulence in the intestinal tract. Here, we discuss our findings in the light of other recent studies describing mechanosensing of the host and force-dependent induction of virulence mechanisms. We discuss potential mechanisms of mechanosensing and mechanotransduction, and the level of conservation across bacterial species.

Microbioligical Hazard Contamination in Fermented Vegetables Sold in Local Markets in Cambodia.

Science.gov (United States)

Chrun, Rithy; Hosotani, Yukie; Kawasaki, Susumu; Inatsu, Yasuhiro

2017-01-01

　Fermented vegetables are common part of Cambodian diet. The food safety status for these foods has not been investigated. This study was conducted to evaluate the microbiological hazards that contaminated fermented vegetables. A total of 68 samples of fermented vegetables were purchased randomly from five wet markets in Phnom Penh. The conventional culture methods for microbiological analysis were used. Coliform bacteria (Escherichia coli, Cronobactersakazakii, and Enterobacter spp.), opportunistic non-Entrobacteriaceae, Enterococcus spp., Staphylococcus spp., and Listeria spp. were found in these fermented foods. The highest contamination rate of Enterococcus spp. was 34% of total fermented vegetable samples, followed by Bacillus spp. coliform bacteria and E. coli (31%, 24% and 10%, respectively). The potential foodborne pathogen, C. sakazakii, was identified in one sample. Fermented mixed vegetables showed higher contamination rate of coliform bacteria (50%) than fermented single-type vegetables (13%). The results showed that fermented vegetables sold in wet market are poor in hygiene. The stage in the processing chain where contamination occurred should be identified and basic sanitary practice should be enforced to improve the food safety of fermented vegetables in Cambodia.

Modulating β-lactoglobulin nanofibril self-assembly at pH 2 using glycerol and sorbitol.

Science.gov (United States)

Dave, Anant C; Loveday, Simon M; Anema, Skelte G; Jameson, Geoffrey B; Singh, Harjinder

2014-01-13

β-Lactoglobulin (β-lg) forms fibrils when heated at 80 °C, pH 2, and low ionic strength (sorbitol (0-50% w/v) on β-lg self-assembly at pH 2. Glycerol and sorbitol stabilize native protein structure and modulate protein functionality by preferential exclusion. In our study, both polyols decreased the rate of β-lg self-assembly but had no effect on the morphology of fibrils. The mechanism of these effects was studied using circular dichroism spectroscopy and SDS-PAGE. Sorbitol inhibited self-assembly by stabilizing β-lg against unfolding and hydrolysis, resulting in fewer fibrillogenic species, whereas glycerol inhibited nucleation without inhibiting hydrolysis. Both polyols increased the viscosity of the solutions, but viscosity appeared to have little effect on fibril assembly, and we believe that self-assembly was not diffusion-limited under these conditions. This is in agreement with previous reports for other proteins assembling under different conditions. The phenomenon of peptide self-assembly can be decoupled from protein hydrolysis using glycerol.

Comparison of separate hydrolysis and fermentation and simultaneous saccharification and fermentation processes for ethanol production from wheat straw by recombinant Escherichia coli strain FBR5

Energy Technology Data Exchange (ETDEWEB)

Saha, Badal C.; Nichols, Nancy N.; Qureshi, Nasib; Cotta, Michael A. [U.S. Department of Agriculture, Agricultural Research Services Peoria, IL (United States). Bioenergy Reserach Unit

2011-11-15

Ethanol production by recombinant Escherichia coli strain FBR5 from dilute acid pretreated wheat straw (WS) by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) was studied. The yield of total sugars from dilute acid (0.5% H2SO4) pretreated (160 C, 10 min) and enzymatically saccharified (pH 5.0, 45 C, 72 h) WS (86 g/l) was 50.0 {+-} 1.4 g/l. The hydrolyzate contained 1,184 {+-} 19 mg furfural and 161 {+-} 1 mg hydroxymethyl furfural per liter. The recombinant E. coli FBR5 could not grow at all at pH controlled at 4.5 to 6.5 in the non-abated wheat straw hydrolyzate (WSH) at 35 C. However, it produced 21.9 {+-} 0.3 g ethanol from non-abated WSH (total sugars, 44.1 {+-} 0.4 g/l) in 90 h including the lag time of 24 h at controlled pH 7.0 and 35 C. The bioabatement of WS was performed by growing Coniochaeta ligniaria NRRL 30616 in the liquid portion of the pretreated WS aerobically at pH 6.5 and 30 C for 15 h. The bacterium produced 21.6 {+-} 0.5 g ethanol per liter in 40 h from the bioabated enzymatically saccharified WSH (total sugars, 44.1 {+-} 0.4 g) at pH 6.0. It produced 24.9 {+-} 0.3 g ethanol in 96 h and 26.7 {+-} 0.0 g ethanol in 72 h per liter from bioabated WSH by batch SSF and fed-batch SSF, respectively. SSF offered a distinct advantage over SHF with respect to reducing total time required to produce ethanol from the bioabated WS. Also, fed-batch SSF performed better than the batch SSF with respect to shortening the time requirement and increase in ethanol yield. (orig.)

Polyamine transporters and polyamines increase furfural tolerance during xylose fermentation with ethanologenic Escherichia coli strain LY180.

Science.gov (United States)

Geddes, Ryan D; Wang, Xuan; Yomano, Lorraine P; Miller, Elliot N; Zheng, Huabao; Shanmugam, Keelnatham T; Ingram, Lonnie O

2014-10-01

Expression of genes encoding polyamine transporters from plasmids and polyamine supplements increased furfural tolerance (growth and ethanol production) in ethanologenic Escherichia coli LY180 (in AM1 mineral salts medium containing xylose). This represents a new approach to increase furfural tolerance and may be useful for other organisms. Microarray comparisons of two furfural-resistant mutants (EMFR9 and EMFR35) provided initial evidence for the importance of polyamine transporters. Each mutant contained a single polyamine transporter gene that was upregulated over 100-fold (microarrays) compared to that in the parent LY180, as well as a mutation that silenced the expression of yqhD. Based on these genetic changes, furfural tolerance was substantially reconstructed in the parent, LY180. Deletion of potE in EMFR9 lowered furfural tolerance to that of the parent. Deletion of potE and puuP in LY180 also decreased furfural tolerance, indicating functional importance of the native genes. Of the 8 polyamine transporters (18 genes) cloned and tested, half were beneficial for furfural tolerance (PotE, PuuP, PlaP, and PotABCD). Supplementing AM1 mineral salts medium with individual polyamines (agmatine, putrescine, and cadaverine) also increased furfural tolerance but to a smaller extent. In pH-controlled fermentations, polyamine transporter plasmids were shown to promote the metabolism of furfural and substantially reduce the time required to complete xylose fermentation. This increase in furfural tolerance is proposed to result from polyamine binding to negatively charged cellular constituents such as nucleic acids and phospholipids, providing protection from damage by furfural. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Genetic Diversity of the fliC Genes Encoding the Flagellar Antigen H19 of Escherichia coli and Application to the Specific Identification of Enterohemorrhagic E. coli O121:H19

Science.gov (United States)

Beutin, Lothar; Delannoy, Sabine

2015-01-01

Enterohemorrhagic Escherichia coli (EHEC) O121:H19 belong to a specific clonal type distinct from other classical EHEC and major enteropathogenic E. coli groups and is regarded as one of the major EHEC serogroups involved in severe infections in humans. Sequencing of the fliC genes associated with the flagellar antigen H19 (fliCH19) revealed the genetic diversity of the fliCH19 gene sequences in E. coli. A cluster analysis of 12 fliCH19 sequences, 4 from O121 and 8 from non-O121 E. coli strains, revealed five different genotypes. All O121:H19 strains fell into one cluster, whereas a second cluster was formed by five non-O121:H19 strains. Cluster 1 and cluster 2 strains differ by 27 single nucleotide exchanges in their fliCH19 genes (98.5% homology). Based on allele discrimination of the fliCH19 genes, a real-time PCR test was designed for specific identification of EHEC O121:H19. The O121 fliCH19 PCR tested negative in 73 E. coli H19 strains that belonged to serogroups other than O121, including 28 different O groups, O-nontypeable H19, and O-rough:H19 strains. The O121 fliCH19 PCR reacted with all 16 tested O121:H19 strains and 1 O-rough:H19 strain which was positive for the O121 wzx gene. A cross-reaction was observed only with E. coli H32 strains which share sequence similarities in the target region of the O121 fliCH19 PCR. The combined use of O-antigen genotyping (O121 wzx) and the detection of O121 fliCH19 allele type contributes to improving the identification and molecular serotyping of EHEC O121:H19 motile and nonmotile strains and variants of these strains lacking stx genes. PMID:25862232

Isolation, Characterization and Antibiotic Resistance of Shiga Toxin-Producing Escherichia coli in Hamburger and Evolution of Virulence Genes stx1, stx2, eaeA and hly by Multiplex PCR

Directory of Open Access Journals (Sweden)

Mohammad Kargar

2013-09-01

Full Text Available Background & Objectives: Shiga toxin-producing Escherichia coli (STEC O157:H7 have emerged as pathogens that can cause food-borne infections and severe and potentially fatal illnesses in humans. E.coli O157:H7 colonizes the digestive tract of cattle and is transmitted to humans by food and water. The objectives of this study were to characterize the prevalence of E.coli O157:H7 isolates in hamburger in Shiraz and to test their antimicrobial sensitivity. Material & Methods: In this research, 428 samples of hamburger were collected from 7 main factories of meat products and enriched in TSB with novobiocin medium at 37ºC. Fermentation of sorbitol and lactose and activities of β- glucuronidase of separated bacteria were examined by using the SMAC and VRBA media and CHROMagar medium. Then isolation of E.coli O157:H7 was confirmed with the use of specific antisera; and with the multiplex PCR method, the presence of E.coli O157:H7 virulence genes – including stx1, stx2, eaeA, and hly – was analyzed. Finally, antibiotic resistance strains were tested with disk diffusion methods. Results: Out of all the examined samples, 264 (61.68% sorbitol-negative bacteria were separated in the CT-SMAC medium. After evaluation with specific antisera, the rate of the recognition of E.coli O157:H7 was 5 (1.17%. The stx1 and eaeA genes were diagnosed in 2 (0.47% cases of these samples. All the isolated bacteria were resistant to penicillin, clindamycin, and erythromycin antibiotics.Conclusion: The presence of STEC in animal products suggests that they may be a potential hazard for human health. A regular monitoring of STEC O157, mainly in hamburger, should be performed to prevent a possible consumer health threat.

Health and Safety Considerations of Fermented Sausages

Directory of Open Access Journals (Sweden)

Askild Holck

2017-01-01

Full Text Available Fermented sausages are highly treasured traditional foods. A large number of distinct sausages with different properties are produced using widely different recipes and manufacturing processes. Over the last years, eating fermented sausages has been associated with potential health hazards due to their high contents of saturated fats, high NaCl content, presence of nitrite and its degradation products such as nitrosamines, and use of smoking which can lead to formation of toxic compounds such as polycyclic aromatic hydrocarbons. Here we review the recent literature regarding possible health effects of the ingredients used in fermented sausages. We also go through attempts to improve the sausages by lowering the content of saturated fats by replacing them with unsaturated fats, reducing the NaCl concentration by partly replacing it with KCl, and the use of selected starter cultures with desirable properties. In addition, we review the food pathogenic microorganisms relevant for fermented sausages (Escherichia coli, Salmonella enterica, Staphylococcus aureus, Listeria monocytogenes, Clostridium botulinum, and Toxoplasma gondii and processing and postprocessing strategies to inhibit their growth and reduce their presence in the products.

Subcellular localization and vacuolar targeting of sorbitol dehydrogenase in apple seed.

Science.gov (United States)

Wang, Xiu-Ling; Hu, Zi-Ying; You, Chun-Xiang; Kong, Xiu-Zhen; Shi, Xiao-Pu

2013-09-01

Sorbitol is the primary photosynthate and translocated carbohydrate in fruit trees of the Rosaceae family. NAD(+)-dependent sorbitol dehydrogenase (NAD-SDH, EC 1.1.1.14), which mainly catalyzes the oxidation of sorbitol to fructose, plays a key role in regulating sink strength in apple. In this study, we found that apple NAD-SDH was ubiquitously distributed in epidermis, parenchyma, and vascular bundle in developing cotyledon. NAD-SDH was localized in the cytosol, the membranes of endoplasmic reticulum and vesicles, and the vacuolar lumen in the cotyledon at the middle stage of seed development. In contrast, NAD-SDH was mainly distributed in the protein storage vacuoles in cotyledon at the late stage of seed development. Sequence analysis revealed there is a putative signal peptide (SP), also being predicated to be a transmembrane domain, in the middle of proteins of apple NAD-SDH isoforms. To investigate whether the putative internal SP functions in the vacuolar targeting of NAD-SDH, we analyzed the localization of the SP-deletion mutants of MdSDH5 and MdSDH6 (two NAD-SDH isoforms in apple) by the transient expression system in Arabidopsis protoplasts. MdSDH5 and MdSDH6 were not localized in the vacuoles after their SPs were deleted, suggesting the internal SP functions in the vacuolar targeting of apple NAD-SDH. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Reduction of Escherichia coli O157:H7 viability on leafy green vegetables by treatment with a bacteriophage mixture and trans-cinnamaldehyde.

Science.gov (United States)

Viazis, Stelios; Akhtar, Mastura; Feirtag, Joellen; Diez-Gonzalez, Francisco

2011-02-01

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were Nal(R) mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (10(4), 10(5), and 10(6) CFU/mL, respectively). Appropriate controls, BEC8 (approx. 10(6) PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain. Copyright © 2010 Elsevier Ltd. All rights reserved.

Production of liquid alkanes by controlling reactivity of sorbitol hydrogenation with a Ni/HZSM-5 catalyst in water

International Nuclear Information System (INIS)

Zhang, Qing; Wang, Tiejun; Xu, Ying; Zhang, Qi; Ma, Longlong

2014-01-01

Graphical abstract: MCM-41-modified Ni/HZSM-5 catalyst was developed by impregnation method with high catalytic performance for sorbitol hydrogenation in water. Appropriate amount of MCM-41 addition can distinctly promote the improvement in the surface structure and modulation of acidic sites of the catalyst. The scission of C–O bond in the sorbitol molecule into liquid alkanes was easily carried out on the catalyst containing more Lewis acidic sites. - Highlights: • Ni/HZSM-5 promoted with MCM-41 is active for sorbitol hydrogenation to liquid alkanes. • Lewis acidic sites of Ni/HZSM-5 can be modulated by pure silica MCM-41. • MCM-41 added can distinctly decrease carbon deposition on the catalyst surface. - Abstract: Liquid fuels derived from renewable biomass are of great importance on the potential substitution for diminishing fossil fuels. The conversion of sorbitol (a product of biomass-derived glucose hydrogenation) into liquid alkanes such as pentane and hexane over the Ni/HZSM-5 catalysts with or without MCM-41 addition was investigated in the presence of hydrogen in water medium. The production distribution of sorbitol hydrogenation can be controlled by adjusting the acidity of the catalyst. The scission of C–C bond in the sorbitol molecule into light C 1 –C 4 alkanes was mainly carried out over Ni/HZSM-5 containing strong Brønsted acid sites, while C–O bond scission into heavier alkanes was dominated over the catalysts added by MCM-41 containing weak Lewis acid sites. The sorbitol conversion and total liquid alkanes selectivity were found to be 67.1% and 98.7% over 2%Ni/HZSM-5 modified by 40 wt% of MCM-41, whereas the corresponding value was 40% and 35.6% over 2%Ni/HZSM-5 in the absence of MCM-41. The effect of MCM-41 on the structure, acidity, and reducibility of Ni/HZSM-5 was investigated by using XRD, Py-IR, IR, and H 2 -TPR. Meanwhile, the resistance of carbon deposition over the catalyst modified by MCM-41 was studied by using TG�

Effect of sorbitol in callus induction and plant regeneration in wheat

African Journals Online (AJOL)

STORAGESEVER

2009-12-01

Dec 1, 2009 ... Key words: Callus induction, plant regeneration, wheat, 2,4-D, sorbitol. INTRODUCTION ... regeneration is better on hormone-free medium or that .... AB (interaction). 15 ... element and creates osmotic stress as reported by.

Control of glucokinase translocation in rat hepatocytes by sorbitol and the cytosolic redox state.

Science.gov (United States)

Agius, L

1994-02-15

In rat hepatocytes cultured in 5 mM glucose, glucokinase activity is present predominantly in a bound state, and during permeabilization of the cells with digitonin in the presence of Mg2+ less than 20% of glucokinase activity is released. However, incubation of hepatocytes with a higher [glucose] [concn. giving half-maximal activation (A50) 15 mM] or with fructose (A50 50 microM) causes translocation of glucokinase from its Mg(2+)-dependent binding site to an alternative site [Agius and Peak (1993) Biochem. J. 296, 785-796]. A comparison of various substrates showed that sorbitol (A50 8 microM) was 6-fold more potent than fructose at causing glucokinase translocation, whereas tagatose was as potent and mannitol was > 10-fold less potent (A50 550 microM). These substrates also stimulate glucose conversion into glycogen with a similar relative potency, suggesting that conversion of glucose into glycogen is dependent on the binding and/or location of glucokinase within the hepatocyte. Ethanol and glycerol inhibited the effects of fructose, sorbitol and glucose on glucokinase translocation, whereas dihydroxy-acetone had a small additive effect at sub-maximal substrate stimulation. The converse effects of glycerol and dihydroxy-acetone suggest a role for the cytosolic NADH/NAD+ redox state in controlling glucokinase translocation. Titrations with three competitive inhibitors of glucokinase did not provide evidence for involvement of glucokinase flux in glucose-induced glucokinase translocation: N-acetylglucosamine inhibited glucose conversion into glycogen, but not glucose-induced glucokinase translocation; glucosamine partially suppressed glucose-induced and fructose-induced glucokinase translocation, at concentrations that caused total inhibition of glucose conversion into glycogen; D-mannoheptulose increased glucokinase release and had an additive effect with glucose. 3,3'-Tetramethylene-glutaric acid (5 mM), an inhibitor of aldose reductase, inhibited glucokinase

Effects of protectant and rehydration conditions on the survival rate and malolactic fermentation efficiency of freeze-dried Lactobacillus plantarum JH287.

Science.gov (United States)

Lee, Sae-Byuk; Kim, Dong-Hwan; Park, Heui-Dong

2016-09-01

In this study, Lactobacillus plantarum JH287 was used as a malolactic fermentation starter in Campbell Early wine production. L. plantarum JH287 was first lyophilized, and the malolactic fermentation potential of freeze-dried L. plantarum JH287 was investigated. Different protective media and rehydration conditions were tested to improve the survival rate of freeze-dried L. plantarum JH287. Optimal protective medium contained 10 % sorbitol and 10 % skim milk. The optimal rehydration condition was a 1-h rehydration time conducted in the same protective media, and the combination of these two methods produced a survival rate of 86.37 %. In addition, a 77.71 % survival rate was achieved using freeze-dried samples that were stored at 4 °C for 2 months. Freeze-dried L. plantarum JH287 and Saccharomyces cerevisiae Fermivin were used to inoculate the Campbell Early grape must to decrease its malic acid content. Using this mixed-fermentation method, wine showed a decrease in malic acid content after 9 days of fermentation. GC-MS analysis detected 15 volatile ester compounds in the wine. A sensory evaluation showed that the taste and aroma of mix-fermented wine were better than those of the control that had not been inoculated with L. plantarum JH287.

Fate of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during storage of fermented green table olives in brine.

Science.gov (United States)

Argyri, Anthoula A; Lyra, Efstathia; Panagou, Efstathios Z; Tassou, Chrysoula C

2013-10-01

The survival of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during the storage of fermented green table olives cv. Halkidiki in brine was studied in parallel with the evolution of lactic acid bacteria (LAB), yeasts and pH. The olives were previously fermented with a starter culture (a potential probiotic strain of Lactobacillus pentosus B281--starter process) or with the indigenous microbiota (control). After the end of fermentation, olives were placed in brine, inoculated with a cocktail of 5 strains of E. coli O157:H7, 5 strains of L. monocytogenes and 4 strains of S. Enteritidis, with a final concentration in the brine of ca. 7.0 log CFU/ml, and subsequently packaged in polyethylene pouches and stored at 20 °C. The population of E. coli O157:H7 reduced gradually and was detected in the brine until the 27th day of storage in both cases (i.e., starter and control process), and on olive fruits until the 19th and 16th days of storage in the starter and control process, respectively. S. Enteritidis population showed also a decrease and it was detected until the 21st day of storage in both brine and olive fruits in both cases. The population of L. monocytogenes declined during storage and it was detected until the 31st day of storage in both brine and olive fruits in both cases, showing a longer survival period in comparison to the other two studied pathogens. The presence of the potential probiotic starter did not affect the pathogen survival. The results demonstrated that even though the growth of the pathogenic strains was not supported, they may survive for a long period in a stressful environment of a fermented product with low pH value (4.2) and high salt concentration (6.0%). These results are a valuable contribution to risk assessment studies related to ready to eat foods in general. Copyright © 2013 Elsevier Ltd. All rights reserved.

Identification and functional properties of dominant lactic acid bacteria isolated from Kahudi, a traditional rapeseed fermented food product of Assam, India

Directory of Open Access Journals (Sweden)

Gunajit Goswami

2017-09-01

Full Text Available Kahudi or Pani tenga is a very unique fermented mustard product of Assam that is prepared by mixing coarsely ground mustard with extracts of acidic Garcinia pedunculata (Thekera or tamarind. Kahudi is produced through a spontaneous and uncontrolled solid state fermentation and very little scientific effort has been directed to understand its microflora and their functional properties. In this paper, we report the microbial flora and their dynamics during Kahudi fermentation with special emphasis on lactic acid bacteria (LAB. LAB were found to be dominant (8 log CFU/g over other microbial flora (4 log CFU/g during the fermentation process leading to Kahudi formation. The microbial load in Kahudi did not include any mycelial molds or pathogenic enteric bacteria. Combination of phenotypic parameters, biochemical tests, and 16S rDNA gene sequencing revealed the dominant group of LAB as Enterococcus durans, Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus casei. The sugar fermentation and enzyme profile analysis revealed the ability of the microbial consortia to metabolize an array of indigestible sugars including D-mannose, mannitol, sorbitol, methyl-α-D-mannopyranoside, methyl-α-D-glucopyranoside, N-acetylglucosamine, amygdalin, and arbutin. Although the isolates showed good acid phosphatase activity they had weak extracellular phytase activity. This is the first report on the microbial dynamics and involvement of LAB during Kahudi fermentation.

Susceptibility of multidrug resistant enterotoxigenic escherichia coli to saponin extract from phyllanthus niruri

International Nuclear Information System (INIS)

Ajibade, V.A.; Famurewa, O.

2013-01-01

Escherichia coli were isolated from 140 samples of blood, urine, stool and water made up of 15.7%, 42.9% and 30.0% and 25.7% respectively. From the samples, 71.9% enterotoxigenic E. coli (ETEC), 14.3% enteropathogenic E. coli (EPEC), 7.1% enterohemorrhagic E. coil (EHEC) and 7.1% enteroinvasive E. coli (EIEC) occurred as diarrheagenic E. coli. Of the ETEC (240) isolates tested for susceptibility to eight conventional antibiotics. 110 (46.0%) showed resistance to all the tested antimicrobial agents. However, of the resistant strains; 24 (22.0%) were multidrug resistant. These were tested against 3.0 mg/mL of saponin extract from phyllanthus niruri and 13 (55.0%) of these were susceptible to the saponin. The antimicrobial activities of saponin from P. niruri are of interest since the crude extract was effective at concentration of 3.0 mg/ml to multiple resistant isolates of EEC. (author)

Hybrid neural network model for simulating sorbitol synthesis by glucose-fructose oxidoreductase in Zymomonas mobilis CP4

Directory of Open Access Journals (Sweden)

Bravo S.

2004-01-01

Full Text Available A hybrid neural network model for simulating the process of enzymatic reduction of fructose to sorbitol process catalyzed by glucose-fructose oxidoreductase in Zymomonas mobilis CP4 is presented. Data used to derive and validate the model was obtained from experiments carried out under different conditions of pH, temperature and concentrations of both substrates (glucose and fructose involved in the reaction. Sonicated and lyophilized cells were used as source of the enzyme. The optimal pH for sorbitol synthesis at 30º C is 6.5. For a value of pH of 6, the optimal temperature is 35º C. The neural network in the model computes the value of the kinetic relationship. The hybrid neural network model is able to simulate changes in the substrates and product concentrations during sorbitol synthesis under pH and temperature conditions ranging between 5 and 7.5 and 25 and 40º C, respectively. Under these conditions the rate of sorbitol synthesis shows important differences. Values computed using the hybrid neural network model have an average error of 1.7·10-3 mole.

Trehalose and sorbitol alter the kinetic pattern of inactivation of glutamate dehydrogenase during drying in levitated microdroplets.

Science.gov (United States)

Lorenzen, Elke; Lee, Geoffrey

2013-12-01

A single-droplet acoustic levitator was used to determine the drying rate and the kinetics of inactivation of glutamate dehydrogenase in the presence of added trehalose or sorbitol. The solution was also spray dried under the same process condition of drying gas temperature on a bench-top machine. Both trehalose and sorbitol delay the point of onset of enzyme inactivation which lies after the critical point of drying. Both carbohydrates also reduce the apparent rate constant of inactivation calculated during the subsequent inactivation phase. The carbohydrates stabilise, therefore, the enzyme during droplet drying and particle formation mainly during the falling rate drying period. There is no difference between the stabilising effects of the two carbohydrates when examined as levitated single droplets. This suggests the importance of water replacement as a stabilising mechanism in the levitated droplets/particles. On spray drying, the trehalose stabilises the enzyme better than does the sorbitol at a drying gas (outlet) temperature of 60°C. This suggests glass formation with the trehalose but not the sorbitol during the very rapid drying process of small-atomised droplets in the spray dryer. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Fermentative hydrogen production by the newly isolated Enterobacter asburiae SNU-1

Energy Technology Data Exchange (ETDEWEB)

Shin, Jong-Hwan; Hyun Yoon, Jong; Eun Kyoung Ahn; Park, Tai Hyun [School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744 (Korea); Kim, Mi-Sun [Biomass Research Team, Korea Institute of Energy Research, Daejeon 305-343 (Korea); Jun Sim, Sang [Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea)

2007-02-15

A new fermentative hydrogen-producing bacterium was isolated from a domestic landfill and identified as Enterobacter asburiae using 16S rRNA gene sequencing and DNA-DNA hybridization methods. The isolated bacterium, designated as Enterobacter asburiae SNU-1, is a new species that has never been examined as a potential hydrogen-producing bacterium. This study examined the hydrogen-producing ability of Enterobacter asburiae SNU-1. During fermentation, the hydrogen was mainly produced in the stationary phase. The hydrogen yield based on the formate consumption was 0.43 mol hydrogen/mol formate. This strain was able to produce hydrogen over a wide range of pH (4-7.5), with the optimum pH being pH 7. The level of hydrogen production was also affected by the initial glucose concentration, and the optimum value was found to be 25 g glucose/l. The maximum and overall hydrogen productivities were 398 and 174 ml/l/hr, respectively, at pH 7 with an initial glucose concentration of 25 g/l. This strain could produce hydrogen from glucose and many other carbon sources such as fructose, sucrose, and sorbitol. (author)

Kefir: composition and evaluation of in situ antagonistic activity against Staphylococcus aureus and Escherichia coli.

Directory of Open Access Journals (Sweden)

Simone Weschenfelder

Full Text Available ABSTRACT The aim of this study was to investigate whether produced kefir meets the identity and quality standards for fermented milks, to check the possibility of assigning a nutrition declaration, and to evaluate the antagonistic activity of the fermented milk against Staphylococcus aureus and Escherichia coli. Two different formulations of kefir (Kefir 1 and Kefir 2 were prepared to determine the percentage composition, minerals, pH, total lactic acid bacteria, and antagonistic activity against Staphylococcus aureus and Escherichia coli. The results of the physicochemical evaluation indicated a statistically significant difference between the formulations, except for the percentage of lipids, Ca, K, Mg and Na. The formulations met the parameters of identity and quality in the fermented milks under evaluation. Possible nutrition declarations for Kefir 1 are 'source of proteins' and 'reduced calorie', and for Kefir 2, 'high protein content' and 'high zinc content'. The fermented milks showed significant antagonistic activity against the tested microorganisms (> 24 h, with no activity seen after this period. Further studies involving kefir are suggested, exploring its potential as a probiotic food, and its inclusion in the diet of the population.

Consistent evidence to support the use of xylitol- and sorbitol-containing chewing gum to prevent dental caries

DEFF Research Database (Denmark)

Twetman, Svante

2009-01-01

DATA SOURCES: Studies were identified using searches with Medline, the Cochrane Library and Google Scholar. STUDY SELECTION: Studies were screened independently and were included if they evaluated the effect of one or more chewing gums containing at least one polyol (xylitol, sorbitol, mannitol...... randomised controlled trials (RCT) of which four were cluster RCT, nine controlled clinical trials (CCT) and four cohort studies]. Two RCT had a Jadad score of three or higher. The mean preventive fraction for the four main gum types are shown in the table 1, results of all except the sorbitol -mannitol...... blend were statistically significant. Sensitivity analyses confirmed the robustness of the findings. CONCLUSIONS: Although research gaps exist, particularly on optimal dosing and relative polyol efficacy, there is consistent evidence to support the use of xylitol- and sorbitol-containing chewing gum...

Effects of dormancy progression and low-temperature response on changes in the sorbitol concentration in xylem sap of Japanese pear during winter season.

Science.gov (United States)

Ito, Akiko; Sugiura, Toshihiko; Sakamoto, Daisuke; Moriguchi, Takaya

2013-04-01

In order to elucidate which physiological event(s) are involved in the seasonal changes of carbohydrate dynamics during winter, we examined the effects of different low temperatures on the carbohydrate concentrations of Japanese pear (Pyrus pyrifolia (Burm.) Nakai). For four winter seasons, large increases in the sorbitol concentration of shoot xylem sap occurred during mid- to late December, possibly due to the endodormancy completion and low-temperature responses. When trees were kept at 15 °C from 3 November to 3 December in order to postpone the initiation and completion of chilling accumulation that would break endodormancy, sorbitol accumulation in xylem sap was always higher from trees with sufficient chilling accumulation than from trees that received insufficient chilling. However, an additional increase in xylem sap sorbitol occurred around late December in trees regardless of whether their chilling accumulation naturally progressed or was postponed. To examine different temperature effects more closely, we compared the carbohydrate concentrations of trees subjected to either 6 or 0 °C treatment. The sorbitol concentration in xylem sap tremendously increased at 0 °C treatment compared with 6 °C treatment. However, an additional increase in xylem sap sorbitol occurred at both the temperatures when sufficient chilling accumulated with a peak coinciding with the peak expression in shoots of the sorbitol transporter gene (PpSOT2). Interestingly, the total carbohydrate concentration of shoots tremendously increased with exposure to 0 °C compared with exposure to 6 °C, but was not affected by the amount of accumulated chilling. Instead, as chilling accumulated the ratio of sorbitol to total soluble sugars in shoots increased. We presumed that carbohydrates in the shoot tissues may be converted to sorbitol and loaded into the xylem sap so that the sorbitol accumulation patterns were synchronized with the progression of dormancy, whereas the total

Escherichia coli pathotypes in Pakistan from consecutive floods in 2010 and 2011.

Science.gov (United States)

Bokhari, Habib; Shah, Muhammad Ali; Asad, Saba; Akhtar, Sania; Akram, Muhammad; Wren, Brendan W

2013-03-01

This study compares Escherichia coli pathotypes circulating among children in Pakistan during the floods of 2010 and 2011 and from sporadic cases outside flood affected areas. Using multiplex polymerase chain reaction 115 of 205 stool samples (56.29%) were positive for diarrheagenic E. coli from specimens taken during the floods compared with 50 of 400 (12.5%) stool samples being positive for sporadic cases. The E. coli pathotypes were categorized as Enteropathogenic E. coli 33 (28.69%) and 13 (26%), Enterotoxigenic E. coli 29 (25.21%) and 15 (30%), Enteroaggregative E. coli 21 (18.2%) and 18 (36%), Enterohemorrhagic E. coli 5 (4.34%) and 1 (2%) from flood and sporadic cases, respectively. Furthermore, patients co-infected with more than one pathotype were 26 (22.60%) and 3 (6%) from flood and sporadic cases, respectively. The study shows an unexpectedly high rate of isolation of E. coli pathotypes suggesting Pakistan as an endemic region that requires active surveillance particularly during flood periods.

Towards a systems level understanding of the oxygen response of Escherichia coli

NARCIS (Netherlands)

Bettenbrock, K.; Bai, H.; Ederer, M.; Green, J.; Hellingwerf, K.J.; Holcombe, M.; Kunz, S.; Rolfe, M.D.; Sanguinetti, G.; Sawodny, O.; Sharma, P.; Steinsiek, S.; Poole, R.K.

2014-01-01

Escherichia coli is a facultatively anaerobic bacterium. With glucose if no external electron acceptors are available, ATP is produced by substrate level phosphorylation. The intracellular redox balance is maintained by mixed-acid fermentation, that is, the production and excretion of several

Substrate inhibition: Oxidation of D-sorbitol and D-mannitol by potassium periodate in alkaline medium

Science.gov (United States)

Lakshman Kumar, Y.; Venkata Nadh, R.; Radhakrishnamurti, P. S.

2014-05-01

In the oxidation of D-sorbitol and D-mannitol by potassium periodate in alkaline media, substrate inhibition was observed with both substrates, i.e., a decrease in the rate of the reaction was observed with an increase in the concentration of substrate. The substrate inhibition was attributed to the formation of stable complex between the substrate and periodate. The reactions were found to be first order in case of periodate and a positive fractional order with hydroxide ions. Arrhenius parameters were calculated for the oxidation of sorbitol and mannitol by potassium periodate in alkali media.

Polyol specificity of recombinant Arabidopsis thaliana sorbitol dehydrogenase studied by enzyme kinetics and in silico modeling

Directory of Open Access Journals (Sweden)

María Francisca eAguayo

2015-02-01

Full Text Available Polyols are enzymatically-produced plant compounds which can act as compatible solutes during periods of abiotic stress. NAD+-dependent SORBITOL DEHYDROGENASE (SDH, E.C. 1.1.1.14 from Arabidopsis thaliana L. (AtSDH is capable of oxidizing several polyols including sorbitol, ribitol and xylitol. In the present study, enzymatic assays using recombinant AtSDH demonstrated a higher specificity constant for xylitol compared to sorbitol and ribitol, all of which are C2 (S and C4 (R polyols. Enzyme activity was reduced by preincubation with ethylenediaminetetraacetic acid (EDTA, indicating a requirement for zinc ions. In humans, it has been proposed that sorbitol becomes part of a pentahedric coordination sphere of the catalytic zinc during the reaction mechanism. In order to determine the validity of this pentahedric coordination model in a plant SDH, homology modeling and Molecular Dynamics simulations of AtSDH ternary complexes with the three polyols were performed using crystal structures of human and Bemisia argentifolii (Genn. (Hemiptera: Aleyrodidae SDHs as scaffolds. The results indicate that the differences in interaction with structural water molecules correlate very well with the observed enzymatic parameters, validate the proposed pentahedric coordination of the catalytic zinc ion in a plant SDH, and provide an explanation for why AtSDH shows a preference for polyols with a chirality of C2 (S and C4 (R.

The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli O103:H25.

Directory of Open Access Journals (Sweden)

Hildegunn Iversen

Full Text Available Enterohemorrhagic E. coli (EHEC is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424 co-cultured with B. thetaiotaomicron (CCUG 10774 or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes and in the presence of spent medium (44 genes, and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS are located on the Locus of enterocyte effacement (LEE pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5 were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium. These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing

Simultaneous saccharification of inulin and starch using commercial glucoamylase and the subsequent bioconversion to high titer sorbitol and gluconic acid.

Science.gov (United States)

An, Kehong; Hu, Fengxian; Bao, Jie

2013-12-01

A new bioprocess for production of sorbitol and gluconic acid from two low-cost feedstocks, inulin and cassava starch, using a commercially available enzyme was proposed in this study. The commercial glucoamylase GA-L NEW from Genencor was found to demonstrate a high inulinase activity for hydrolysis of inulin into fructose and glucose. The glucoamylase was used to replace the expensive and not commercially available inulinase enzyme for simultaneous saccharification of inulin and starch into high titer glucose and fructose hydrolysate. The glucose and fructose in the hydrolysate were converted into sorbitol and gluconic acid using immobilized whole cells of the recombinant Zymomonas mobilis strain. The high gluconic acid concentration of 193 g/L and sorbitol concentration of 180 g/L with the overall yield of 97.3 % were obtained in the batch operations. The present study provided a practical production method of sorbitol and gluconic acid from low cost feedstocks and enzymes.

Sorbitol dehydration into isosorbide in a molten salt hydrate medium

NARCIS (Netherlands)

Li, J.; Spina, A.; Moulijn, J.A.; Makkee, M.

2013-01-01

The sorbitol conversion in a molten salt hydrate medium (ZnCl2; 70 wt% in water) was studied. Dehydration is the main reaction, initially 1,4- and 3,6-anhydrosorbitol are the main products that are subsequently converted into isosorbide; two other anhydrohexitols, (1,5- and 2,5-), formed are in less

The influence of sorbitol on the production of cellulases and xylanases in an airlift bioreactor.

Science.gov (United States)

Ritter, Carla Eliana Todero; Fontana, Roselei Claudete; Camassola, Marli; da Silveira, Maurício Moura; Dillon, Aldo José Pinheiro

2013-11-01

The production of cellulases and xylanases by Penicillium echinulatum in an airlift bioreactor was evaluated. In batch production, we tested media with isolated or associated cellulose and sorbitol. In fed-batch production, we tested cellulose addition at two different times, 30 h and 48 h. Higher liquid circulation velocities in the downcomer were observed in sorbitol 10 g L(-1) medium. In batch production, higher FPA (filter paper activity) and endoglucanase activities were obtained with cellulose (7.5 g L(-1)) and sorbitol (2.5 g L(-1)), 1.0 U mL(-1) (120 h) and 6.4 U m L(-1) (100 h), respectively. For xylanases, the best production condition was cellulose 10 g L(-1), which achieved 5.5 U mL(-1) in 64 h. The fed-batch process was favorable for obtaining xylanases, but not for FPA and endoglucanases, suggesting that in the case of cellulases, the inducer must be added early in the process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solvent-Free Polymerization of L-Aspartic Acid in the Presence of D-Sorbitol to Obtain Water Soluble or Network Copolymers

Science.gov (United States)

L-aspartic acid was thermally polymerized in the presence of D-sorbitol with the goal of synthesizing new, higher molecular weight water soluble and absorbent copolymers. No reaction occurred when aspartic acid alone was heated at 170 or 200 degrees C. In contrast, heating sorbitol and aspartic ac...

Sorbitol as an efficient reducing agent for laser-induced copper deposition

Science.gov (United States)

Kochemirovsky, V. A.; Logunov, L. S.; Safonov, S. V.; Tumkin, I. I.; Tver'yanovich, Yu. S.; Menchikov, L. G.

2012-10-01

We have pioneered in revealing the fact that sorbitol may be used as an efficient reducing agent in the process of laser-induced copper deposition from solutions; in this case, it is possible to obtain copper lines much higher quality than by using conventional formalin.

Effects of olestra and sorbitol consumption on objective measures of diarrhea: impact of stool viscosity on common gastrointestinal symptoms.

Science.gov (United States)

McRorie, J; Zorich, N; Riccardi, K; Bishop, L; Filloon, T; Wason, S; Giannella, R

2000-02-01

The aim of this study was to determine the effects of olestra and sorbitol consumption on three accepted objective measures of diarrhea (stool output >250 g/day, liquid/watery stools, bowel movement frequency >3/day), and how stool composition influences reports of common gastrointestinal symptoms. A double-blind, placebo-controlled study compared the effects of sorbitol (40 g/day in candy), a poorly absorbed sugar-alcohol with known osmotic effects, with those of olestra (20 or 40 g/day in potato chips), a nonabsorbed fat, on objective measures of stool composition and GI symptoms. Sixty-six subjects resided on a metabolic ward for 12 days: 2 days lead-in, 4 days baseline, 6 days treatment. Sorbitol 40 g/day resulted in loose/liquid stools within 1-3 h of consumption. In contrast, olestra resulted in a dose-responsive stool softening effect after 2-4 days of consumption. Subjects reported "diarrhea" when mean stool apparent viscosity (peak force (PF), g) decreased from a perceived "normal" (mean +/- SE, 1355 +/- 224 g PF; firm stool) to loose (260 +/- 68 g PF) stool. Mean apparent viscosity of stool during treatment: placebo, 1363 +/- 280 g (firm); olestra 20 g/day 743 +/- 65 g (soft); olestra 40 g/day, 563 +/- 105 g (soft); and sorbitol 40 g/day, 249 +/- 53 g (loose). Of the 1098 stool samples collected, 38% (419/1098) were rated by subjects as "diarrhea," yet only 2% of treatment days (all in the sorbitol treatment group) met commonly accepted criteria for a clinical diarrhea. Sorbitol, but not olestra, increased the severity of abdominal cramping, urgency and nausea compared to placebo. Olestra consumption, at levels far in excess of normal snacking conditions, resulted in a gradual stool softening effect after several days of consumption, did not meet any of the three objective measures of diarrhea, and did not increase GI symptoms. Sorbitol consumption, at only 80% of the dose requiring a "laxative effect" information label, resulted in rapid onset loose

Antimicrobial potential of triticale stillage after lactic acid fermentation with Lactobacillus fermentum PL-1

Directory of Open Access Journals (Sweden)

Kujundžić Žužana

2013-01-01

Full Text Available This study is concerned with the testing of antimicrobial activity of triticale stillage obtained after lactic fermentation by Lactobacillus fermentum PL-1. The antimicrobial tests were performed using the disc-diffusion and agar well diffusion methods. It was found that fermented triticale stillage after lactic acid fermentation exhibited an inhibitory effect towards tested Gram positive and Gram negative bacteria: Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis. The triticale stillage without addition of CaCO3 before fermentation showed a stronger antimicrobial effect in comparison with the triticale stillage with added CaCO3. Triticale stillage after lactic acid fermentation did not show any antifungal effect on the growth of tested moulds (Alternaria alternata, Aspergillus versicolor, Penicillium brevicompactum, and Fusarium subglutinans. [Projekat Ministarstva nauke Republike Srbije, br. TR-31017

Blending of soluble corn fiber with pullulan, sorbitol, or fructose attenuates glycemic and insulinemic responses in the dog and affects hydrolytic digestion in vitro.

Science.gov (United States)

de Godoy, M R C; Knapp, B K; Bauer, L L; Swanson, K S; Fahey, G C

2013-08-01

The objective of these experiments was to measure in vitro hydrolytic digestion and glycemic and insulinemic responses of select carbohydrate blends, all containing the novel carbohydrate soluble corn fiber (SCF). Two SCF that varied in their method of production were used to formulate the carbohydrate blends. One set of blends contained a SCF that was spray dried (SCFsd) and then blended with different amounts of either pullulan, sorbitol, or fructose. The other set of blends contained a SCF produced using longer evaporation time (SCF) and then blended with different ratios of pullulan, sorbitol, and fructose. Free sugar concentrations found in the individual SCFsd and SCF substrates were low but varied. Spray-dried soluble corn fiber had a reduced free sugar concentration compared with SCF (2.8 vs. 14.2%). Glucose was the main free sugar found in both SCFsd and SCF but at different concentrations (2.7 vs. 12.7%, respectively). The majority of the SCFsd blends were completely hydrolyzed to their monosaccharide components. Glucose accounted for most of the hydrolyzed monosaccharides for SCFsd and all the SCFsd blends. Hydrolyzed monosaccharide concentrations for the SCF:pullulan:sorbitol:fructose blends followed similar trends to the SCFsd blends where greater percentages of fructose and sorbitol resulted in decreased (P sorbitol. Total released monosaccharides were high in SCFsd blends containing either 50% fructose or sorbitol, but the combination resulted in reduced concentrations of glucose released (P sorbitol:fructose blends also had intermediate to high released monosaccharides as a result of in vitro hydrolytic digestion. All SCF blends resulted in decreased glycemic and insulinemic responses compared with the maltodextrin control (P sorbitol in the blends had the greatest impact on glycemic and insulinemic responses, even at concentrations as low as 5% of the blends. Overall, SCF and their blends may prove beneficial as components of low glycemic

Selective electrocatalytic oxidation of sorbitol to fructose and sorbose.

Science.gov (United States)

Kwon, Youngkook; de Jong, Ed; van der Waal, Jan Kees; Koper, Marc T M

2015-03-01

A new electrocatalytic method for the selective electrochemical oxidation of sorbitol to fructose and sorbose is demonstrated by using a platinum electrode promoted by p-block metal atoms. By the studying a range of C4, C5 and C6 polyols, it is found that the promoter interferes with the stereochemistry of the polyol and thereby modifies its reactivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Economics of membrane occupancy and respiro-fermentation

Science.gov (United States)

Zhuang, Kai; Vemuri, Goutham N; Mahadevan, Radhakrishnan

2011-01-01

The simultaneous utilization of efficient respiration and inefficient fermentation even in the presence of abundant oxygen is a puzzling phenomenon commonly observed in bacteria, yeasts, and cancer cells. Despite extensive research, the biochemical basis for this phenomenon remains obscure. We hypothesize that the outcome of a competition for membrane space between glucose transporters and respiratory chain (which we refer to as economics of membrane occupancy) proteins influences respiration and fermentation. By incorporating a sole constraint based on this concept in the genome-scale metabolic model of Escherichia coli, we were able to simulate respiro-fermentation. Further analysis of the impact of this constraint revealed differential utilization of the cytochromes and faster glucose uptake under anaerobic conditions than under aerobic conditions. Based on these simulations, we propose that bacterial cells manage the composition of their cytoplasmic membrane to maintain optimal ATP production by switching between oxidative and substrate-level phosphorylation. These results suggest that the membrane occupancy constraint may be a fundamental governing constraint of cellular metabolism and physiology, and establishes a direct link between cell morphology and physiology. PMID:21694717

The effect of increasing chitosan on the characteristics of bioplastic from starch talas (Colocasia esculenta) using plasticizer sorbitol

Science.gov (United States)

Ginting, M. H. S.; Lubis, M.; Sidabutar, T.; Sirait, T. P.

2018-03-01

The aims of this research to determine the profile of starch gelatinization, bioplastic and the effect of increasing chitosan and sorbitol to the properties of tensile strength and elongation of break bioplastic. Preparation of bioplastics was used by casting method, that is 30% w/v solution of starch mixed with chitosan solution (0.5 w/v; 1 w/v; 1.5 w/v; 2 w/v; and 2.5 w/v) and plasticizer sorbitol (10 % w/w; 20 % w/w; 30 % w/w; 40 % w/w and 50 % w/w) were heated using a hotplate magnetic stirrer at 750C. The results of Rapid Visco Analyzer (RVA) obtained by starch and bioplastic gelatinization temperature of 72.94°C 77.72°C with peak viscosity 6632 cP and 3476 cP. Analysis of Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) obtained the change a functional group of bioplastic OH at wave number 3765 cm-1 and uneven chitosan distribution, and there is still an empty fraction. The addition of chitosan and sorbitol had an effect on tensile strength and elongation at break, tensile strength and elongation at break the highest of 8.36 MPa and 22.06% in starch composition 30%, 2.5 w/v chitosan and sorbitol 30% w/w.

Utilization starch of jackfruit seed (Artocarpus heterophyllus) as raw material for bioplastics manufacturing using sorbitol as plasticizer and chitosan as filler

Science.gov (United States)

Lubis, M.; Harahap, M. B.; Manullang, A.; Alfarodo; Ginting, M. H. S.; Sartika, M.

2017-01-01

Starch is a natural polymer that can be used for the production of bioplastics because its source is abundant, renewable and easily degraded. Jackfruit seeds can be used as raw material for bioplastics because its contains starch. The aim of this study to determine the characteristics of jackfruit seeds and determine the effect of chitosan and sorbitol on the physicochemical properties of bioplastics from jackfruit seeds. Starch is extracted from jackfruit seeds were then characterized to determine its chemical composition. In the manufacture of bioplastics starch composition jackfruit seeds - chitosan used was 7: 3, 8: 2 and 9: 1 (g/g), while the concentration of sorbitol used was 20%, 25%, 30%, 35%, and 40% by weight dry ingredients. From the analysis of jackfruit seed starch obtained water content of 6.04%, ash content of 1.08%, the starch content of 70.22%, 16.39% amylose content, amylopectin content of 53.83%, 4.68% protein content, fat content 0.54%. The best conditions of starch bioplastics jackfruit seeds obtained at a ratio of starch: chitosan (w/w) = 8: 2 and the concentration of plasticizer sorbitol 25% with tensile strength 13.524 MPa. From the results of FT-IR analysis indicated an increase for the OH group and the group NH on bioplastics due to the addition of chitosan and sorbitol. The results of mechanical tests is further supported by analysis of scanning electron microscopy (SEM) showing jackfruit seed starch has a small granule size with the size of 7.6 μm and in bioplastics with chitosan filler and plasticizer sorbitol their fracture surface is smooth and slightly hollow compared bioplastics without fillers chitosan and plasticizer sorbitol.

Pathogenic Potential to Humans of Bovine Escherichia coli O26, Scotland

Science.gov (United States)

Rosser, Tracy; Allison, Lesley J.; Courcier, Emily; Evans, Judith; McKendrick, Iain J.; Pearce, Michael C.; Handel, Ian; Caprioli, Alfredo; Karch, Helge; Hanson, Mary F.; Pollock, Kevin G.J.; Locking, Mary E.; Woolhouse, Mark E.J.; Matthews, Louise; Low, J. Chris; Gally, David L.

2012-01-01

Escherichia coli O26 and O157 have similar overall prevalences in cattle in Scotland, but in humans, Shiga toxin–producing E. coli O26 infections are fewer and clinically less severe than E. coli O157 infections. To investigate this discrepancy, we genotyped E. coli O26 isolates from cattle and humans in Scotland and continental Europe. The genetic background of some strains from Scotland was closely related to that of strains causing severe infections in Europe. Nonmetric multidimensional scaling found an association between hemolytic uremic syndrome (HUS) and multilocus sequence type 21 strains and confirmed the role of stx2 in severe human disease. Although the prevalences of E. coli O26 and O157 on cattle farms in Scotland are equivalent, prevalence of more virulent strains is low, reducing human infection risk. However, new data on E. coli O26–associated HUS in humans highlight the need for surveillance of non-O157 enterohemorrhagic E. coli and for understanding stx2 phage acquisition. PMID:22377426

Effect of Xylitol on Growth of Streptococcus pneumoniae in the Presence of Fructose and Sorbitol

Science.gov (United States)

Tapiainen, Terhi; Kontiokari, Tero; Sammalkivi, Laura; Ikäheimo, Irma; Koskela, Markku; Uhari, Matti

2001-01-01

Xylitol is effective in preventing acute otitis media by inhibiting the growth of Streptococcus pneumoniae. To clarify this inhibition we used fructose, which is known to block similar growth inhibition observed in Streptococcus mutans. In addition, we evaluated the efficacy of sorbitol in inhibiting the growth of pneumococci, as sorbitol is widely used for indications similar to those for which xylitol is used. The addition of 5% xylitol to the growth medium resulted in marked growth inhibition, an effect which was totally eliminated in the presence of 1, 2.5, or 5% fructose but not in the presence of 1 or 5% glucose, 1% galactose, or 1% sucrose. This finding implies that xylitol-induced inhibition of pneumococcal growth is mediated via the fructose phosphotransferase system in a way similar to that in which mutans group streptococcal growth is inhibited. The addition of sorbitol at concentrations of 1, 2.5, or 5% to the growth medium did not affect the growth of pneumococci and neither inhibited nor enhanced the xylitol-induced growth impairment. Thus, it seems that xylitol is the only commercially used sugar substitute proven to have an antimicrobial effect on pneumococci. PMID:11120960

Sweet taste in apple: the role of sorbitol, individual sugars, organic acids and volatile compounds

Science.gov (United States)

Aprea, Eugenio; Charles, Mathilde; Endrizzi, Isabella; Laura Corollaro, Maria; Betta, Emanuela; Biasioli, Franco; Gasperi, Flavia

2017-03-01

Sweetness is one of the main drivers of consumer preference, and thus is given high priority in apple breeding programmes. Due to the complexity of sweetness evaluation, soluble solid content (SSC) is commonly used as an estimation of this trait. Nevertheless, it has been demonstrated that SSC and sweet taste are poorly correlated. Though individual sugar content may vary greatly between and within apple cultivars, no previous study has tried to investigate the relationship between the amount of individual sugars, or ratios of these, and apple sweetness. In this work, we quantified the major sugars (sucrose, glucose, fructose, xylose) and sorbitol and explored their influence on perceived sweetness in apple; we also related this to malic acid content, SSC and volatile compounds. Our data confirmed that the correlation between sweetness and SSC is weak. We found that sorbitol content correlates (similarly to SSC) with perceived sweetness better than any other single sugar or total sugar content. The single sugars show no differentiable importance in determining apple sweetness. Our predictive model based on partial least squares regression shows that after sorbitol and SSC, the most important contribution to apple sweetness is provided by several volatile compounds, mainly esters and farnesene.

21 CFR 180.25 - Mannitol.

Science.gov (United States)

2010-04-01

... fructose. (2) The fermentation of sugars or sugar alcohols such as glucose, sucrose, fructose, or sorbitol using the yeast Zygosaccharomyces rouxii. (3) A pure culture fermentation of sugars such as fructose...

Photosystem I shows a higher tolerance to sorbitol-induced osmotic stress than photosystem II in the intertidal macro-algae Ulva prolifera (Chlorophyta).

Science.gov (United States)

Gao, Shan; Zheng, Zhenbing; Gu, Wenhui; Xie, Xiujun; Huan, Li; Pan, Guanghua; Wang, Guangce

2014-10-01

The photosynthetic performance of the desiccation-tolerant, intertidal macro-algae Ulva prolifera was significantly affected by sorbitol-induced osmotic stress. Our results showed that photosynthetic activity decreased significantly with increases in sorbitol concentration. Although the partial activity of both photosystem I (PS I) and photosystem II (PS II) was able to recover after 30 min of rehydration, the activity of PS II decreased more rapidly than PS I. At 4 M sorbitol concentration, the activity of PS II was almost 0 while that of PS I was still at about one third of normal levels. Following prolonged treatment with 1 and 2 M sorbitol, the activity of PS I and PS II decreased slowly, suggesting that the effects of moderate concentrations of sorbitol on PS I and PS II were gradual. Interestingly, an increase in non-photochemical quenching occurred under these conditions in response to moderate osmotic stress, whereas it declined significantly under severe osmotic stress. These results suggest that photoprotection in U. prolifera could also be induced by moderate osmotic stress. In addition, the oxidation of PS I was significantly affected by osmotic stress. P700(+) in the thalli treated with high concentrations of sorbitol could still be reduced, as PS II was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), but it could not be fully oxidized. This observation may be caused by the higher quantum yield of non-photochemical energy dissipation in PS I due to acceptor-side limitation (Y(NA)) during rehydration in seawater containing DCMU. © 2014 Scandinavian Plant Physiology Society.

Molecular motions in sucrose-PVP and sucrose-sorbitol dispersions-II. Implications of annealing on secondary relaxations.

Science.gov (United States)

Bhattacharya, Sisir; Bhardwaj, Sunny P; Suryanarayanan, Raj

2014-10-01

To determine the effect of annealing on the two secondary relaxations in amorphous sucrose and in sucrose solid dispersions. Sucrose was co-lyophilized with either PVP or sorbitol, annealed for different time periods and analyzed by dielectric spectroscopy. In an earlier investigation, we had documented the effect of PVP and sorbitol on the primary and the two secondary relaxations in amorphous sucrose solid dispersions (1). Here we investigated the effect of annealing on local motions, both in amorphous sucrose and in the dispersions. The average relaxation time of the local motion (irrespective of origin) in sucrose, decreased upon annealing. However, the heterogeneity in relaxation time distribution as well as the dielectric strength decreased only for β1- (the slower relaxation) but not for β2-relaxations. The effect of annealing on β2-relaxation times was neutralized by sorbitol while PVP negated the effect of annealing on both β1- and β2-relaxations. An increase in local mobility of sucrose brought about by annealing could be negated with an additive.

A physicochemical study of sugar palm (Arenga Pinnata) starch films plasticized by glycerol and sorbitol

Science.gov (United States)

Poeloengasih, Crescentiana D.; Pranoto, Yudi; Hayati, Septi Nur; Hernawan, Rosyida, Vita T.; Prasetyo, Dwi J.; Jatmiko, Tri H.; Apriyana, Wuri; Suwanto, Andri

2016-02-01

The present work explores the physicochemical characteristics of sugar palm starch film for a potential hard capsule purpose. Sugar palm (Arenga pinnata) starch films were plasticized with glycerol or sorbitol in various concentrations (30% up to 50% w/w starch). Their effects on physicochemical properties of the films were investigated. The results showed that sugar palm starch was successfully developed as the main material of film using casting method. Incorporation of both glycerol or sorbitol affected the properties of films in different ways. It was found that thickness and solubility increased as plasticizer concentration increased, whereas retraction ratio, swelling degree and swelling thickness decreased with the increased plasticizer concentration.

L-Cysteine Metabolism and Fermentation in Microorganisms.

Science.gov (United States)

Takagi, Hiroshi; Ohtsu, Iwao

L-Cysteine is an important amino acid both biologically and commercially. Although most amino acids are industrially produced by microbial fermentation, L-cysteine has been mainly produced by protein hydrolysis. Due to environmental and safety problems, synthetic or biotechnological products have been preferred in the market. Here, we reviewed L-cysteine metabolism, including biosynthesis, degradation, and transport, and biotechnological production (including both enzymatic and fermentation processes) of L-cysteine. The metabolic regulation of L-cysteine including novel sulfur metabolic pathways found in microorganisms is also discussed. Recent advancement in biochemical studies, genome sequencing, structural biology, and metabolome analysis has enabled us to use various approaches to achieve direct fermentation of L-cysteine from glucose. For example, worldwide companies began to supply L-cysteine and its derivatives produced by bacterial fermentation. These companies successfully optimized the original metabolism of their private strains. Basically, a combination of three factors should be required for improving L-cysteine fermentation: that is, (1) enhancing biosynthesis: overexpression of the altered cysE gene encoding feedback inhibition-insensitive L-serine O-acetyltransferase (SAT), (2) weakening degradation: knockout of the genes encoding L-cysteine desulfhydrases, and (3) exploiting export system: overexpression of the gene involved in L-cysteine transport. Moreover, we found that "thiosulfate" is much more effective sulfur source than commonly used "sulfate" for L-cysteine production in Escherichia coli, because thiosulfate is advantageous for saving consumption of NADPH and relating energy molecules.

Characteristics of fermented plant beverages in southern Thailand

Directory of Open Access Journals (Sweden)

Charernjiratrakul, W.

2005-05-01

Full Text Available The characteristics of fermented plant beverages based on a sensory test, physico-chemical properties, enumeration of microorganisms present and their microbiological quality were investigated. A total of 19 samples of beverages collected from various sources in southern Thailand were examined. It was found that odor, color and clarity and the presence of Cu, Zn, K and Na were mainly dependent on the types of plant used and the additive of sugar or honey. Therefore, the appearance of the beverages was light brown and dark brown. An ester smell was occasionally detected. The fermented plant beverages had sour flavor that developed during fermentation and a little sweetness from residual sugar. The taste was related to the amounts of organic acid and sugar as measured in the ranges of 0.98-7.13% (pH 2.63-3.72 and 0.21-4.20%, respectively. The levels of alcohols measured as ethanol were between 0.03-3.32% and methanol in a range of 0.019 0.084%. Methanol production was dependent on both the fermentation process and the plant used. Total coliforms and Escherichia coli were not detected in any sample, whereas other microbes were detected in some samples as were total bacterial count, lactic acid bacteria, yeast and mold in amounts that differed depending on the fermentation time and also the level of sanitation of the production process.

Variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de macieira durante a dormência Variations of glucose, frutose and sorbitol content in buds and stems of apple tree during the dormancy period

Directory of Open Access Journals (Sweden)

Ruy Inacio Neiva de Carvalho

2006-12-01

Full Text Available O objetivo deste trabalho foi determinar as variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de um ano de macieira durante o período de dormência. Os ramos da cultivar "Imperial Gala" foram coletados em Porto Amazonas-PR, em intervalos de 21 dias, de abril a agosto (19/04, 10/05, 31/05, 21/06, 12/07, 02/08 e 23/08, e receberam ou não tratamento com frio suplementar de 1.440 horas à temperatura de 4 a 7°C. As análises dos carboidratos foram realizadas em gemas e porções de ramos adjacentes às primeiras por cromatografia líquida de alta eficiência (HPLC. Ocorreu um acúmulo de glucose, frutose e sorbitol nas gemas de macieira durante a dormência. O acúmulo de glucose e frutose nos ramos aconteceu até o início de agosto quando, em seguida, houve redução, enquanto o sorbitol decresceu até junho e, em seguida, elevou-se até o final de agosto. O tratamento com frio ao longo da dormência modificou as variações dos conteúdos de carboidratos nas gemas e ramos de macieira.This research was aimed at evaluating the variations of glucose, frutose and sorbitol content in one year old buds and stems of apple trees during the dormancy period. The stems of cv. Imperial Gala were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd and were treated or not with 1,440 hours of chill (4 to 7°C. The carbohydrates were analysed in buds and stem tissues close to buds by high performance liquid chromatography (HPLC. There was an increase of glucose, frutose and sorbitol content in apple tree buds during the dormancy. An increase of glucose and frutose content in stems occured until August 2nd followed by a significative reduction, while the sorbitol content decreased until June 21st followed by an increase until August 31st. The chill treatment during the dormancy period modified the variations of

Plasma glucagon-like peptide 1 and peptide YY levels are not altered in symptomatic fructose-sorbitol malabsorption

DEFF Research Database (Denmark)

Valeur, Jørgen; Øines, Eliann; Morken, Mette Helvik

2008-01-01

consecutive patients with functional abdominal complaints, referred to our clinic for investigation of self-reported food hypersensitivity, were included in the study and compared with 15 healthy volunteers. All subjects ingested a mixture of 25 g fructose and 5 g sorbitol. Pulmonary hydrogen and methane...... excretion and plasma glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) levels were measured during the next 3 h. Both habitual and post-test symptoms were assessed. RESULTS: Malabsorption of fructose and sorbitol was present in 61% of the patients and 73% of the controls. Nevertheless, the patients...

Production of Starch Based Bioplastic from Cassava Peel Reinforced with Microcrystalline Celllulose Avicel PH101 Using Sorbitol as Plasticizer

Science.gov (United States)

Maulida; Siagian, M.; Tarigan, P.

2016-04-01

The production of starch based bioplastics from cassava peel reeinforced with microcrystalline cellulose using sorbitol as plasticizer were investigated. Physical properties of bioplastics were determined by density, water uptake, tensile strength and Fourier Transform Infrared Spectroscopy. Bioplastics were prepared from cassava peel starch plasticized using sorbitol with variation of 20; 25; 30% (wt/v of sorbitol to starch) reinforced with microcrystalline celllulose (MCC) Avicel PH101 fillers with range of 0 to 6% (wt/wt of MCC to starch). The results showed improvement in tensile strength with higher MCC content up to 9, 12 mpa compared to non-reinforced bioplastics. This could be mainly attributed to the strong hydrogen bonds between MCC and starch. On the contrary, the addition of MCC decreased the elongation at break, density and water uptake. Fourier Transform Infrared Spectroscopy showed the functional groups of bioplastics, which the majority of O-H groups were found at the bioplastics with reinforcing filler MCC that represented substantial hydrogen bonds. The highest tensile strength value was obtained for bioplastic with MCC content 6% and sorbitol content 20%. With good adhesion between MCC and starch the production of bioplastics could be widely used as a substitute for conventional plastics with more benefits to the environment.

Production of Starch Based Bioplastic from Cassava Peel Reinforced with Microcrystalline Celllulose Avicel PH101 Using Sorbitol as Plasticizer

International Nuclear Information System (INIS)

Maulida; Siagian, M; Tarigan, P

2016-01-01

The production of starch based bioplastics from cassava peel reeinforced with microcrystalline cellulose using sorbitol as plasticizer were investigated. Physical properties of bioplastics were determined by density, water uptake, tensile strength and Fourier Transform Infrared Spectroscopy. Bioplastics were prepared from cassava peel starch plasticized using sorbitol with variation of 20; 25; 30% (wt/v of sorbitol to starch) reinforced with microcrystalline celllulose (MCC) Avicel PH101 fillers with range of 0 to 6% (wt/wt of MCC to starch). The results showed improvement in tensile strength with higher MCC content up to 9, 12 mpa compared to non-reinforced bioplastics. This could be mainly attributed to the strong hydrogen bonds between MCC and starch. On the contrary, the addition of MCC decreased the elongation at break, density and water uptake. Fourier Transform Infrared Spectroscopy showed the functional groups of bioplastics, which the majority of O-H groups were found at the bioplastics with reinforcing filler MCC that represented substantial hydrogen bonds. The highest tensile strength value was obtained for bioplastic with MCC content 6% and sorbitol content 20%. With good adhesion between MCC and starch the production of bioplastics could be widely used as a substitute for conventional plastics with more benefits to the environment. (paper)

A mannitol/sorbitol receptor stimulates dietary intake in Tribolium castaneum.

Science.gov (United States)

Takada, Tomoyuki; Sato, Ryoichi; Kikuta, Shingo

2017-01-01

In insects, perception of chemical stimuli is involved in the acceptance or rejection of food. Gustatory receptors (Grs) that regulate external signals in chemosensory organs have been found in many insects. Tribolium castaneum, a major pest of stored products, possesses over 200 Gr genes. An expanded repertoire of Gr genes appears to be required for diet recognition in species that are generalist feeders; however, it remains unclear whether T. castaneum recognizes a suite of chemicals common to many products or whether its feeding is activated by specific chemicals, and whether its Grs are involved in feeding behavior. It is difficult to determine the food preferences of T. castaneum based on dietary intake due to a lack of appropriate methodology. This study established a novel dietary intake estimation method using gypsum, designated the TribUTE (Tribolium Urges To Eat) assay. For this assay, T. castaneum adults were fed a gypsum block without added organic compounds. Sweet preference was determined by adding sweeteners and measuring the amount of gypsum in the excreta. Mannitol was the strongest activator of T. castaneum dietary intake. In a Xenopus oocyte expression, TcGr20 was found to be responsible for mannitol and sorbitol responses, but not for responses to other tested non-volatile compounds. The EC50 values of TcGr20 for mannitol and sorbitol were 72.6 mM and 90.6 mM, respectively, suggesting that TcGr20 is a feasible receptor for the recognition of mannitol at lower concentrations. We used RNAi and the TribUTE assay to examine whether TcGr20 expression was involved in mannitol recognition. The amounts of excreta in TcGr20 dsRNA-injected adults decreased significantly, despite the presence of mannitol, compared to control adults. Taken together, our results indicate that T. castaneum adults recognized mannitol/sorbitol using the TcGr20 receptor, thereby facilitating the dietary intake of these compounds.

A mannitol/sorbitol receptor stimulates dietary intake in Tribolium castaneum.

Directory of Open Access Journals (Sweden)

Tomoyuki Takada

Full Text Available In insects, perception of chemical stimuli is involved in the acceptance or rejection of food. Gustatory receptors (Grs that regulate external signals in chemosensory organs have been found in many insects. Tribolium castaneum, a major pest of stored products, possesses over 200 Gr genes. An expanded repertoire of Gr genes appears to be required for diet recognition in species that are generalist feeders; however, it remains unclear whether T. castaneum recognizes a suite of chemicals common to many products or whether its feeding is activated by specific chemicals, and whether its Grs are involved in feeding behavior. It is difficult to determine the food preferences of T. castaneum based on dietary intake due to a lack of appropriate methodology. This study established a novel dietary intake estimation method using gypsum, designated the TribUTE (Tribolium Urges To Eat assay. For this assay, T. castaneum adults were fed a gypsum block without added organic compounds. Sweet preference was determined by adding sweeteners and measuring the amount of gypsum in the excreta. Mannitol was the strongest activator of T. castaneum dietary intake. In a Xenopus oocyte expression, TcGr20 was found to be responsible for mannitol and sorbitol responses, but not for responses to other tested non-volatile compounds. The EC50 values of TcGr20 for mannitol and sorbitol were 72.6 mM and 90.6 mM, respectively, suggesting that TcGr20 is a feasible receptor for the recognition of mannitol at lower concentrations. We used RNAi and the TribUTE assay to examine whether TcGr20 expression was involved in mannitol recognition. The amounts of excreta in TcGr20 dsRNA-injected adults decreased significantly, despite the presence of mannitol, compared to control adults. Taken together, our results indicate that T. castaneum adults recognized mannitol/sorbitol using the TcGr20 receptor, thereby facilitating the dietary intake of these compounds.

Induction studies with Escherichia coli expressing recombinant interleukin-13 using multi-parameter flow cytometry

DEFF Research Database (Denmark)

Shitu, J. O.; Woodley, John; Wnek, R.

2009-01-01

The expression of interleukin-13 (IL13) following induction with IPTG in Escherichia coli results in metabolic changes as indicated by multi-parameter flow cytometry and traditional methods of fermentation profiling (O-2 uptake rate, CO2 evolution rate and optical density measurements). Induction...

Photocatalysis-assisted water filtration: using TiO2-coated vertically aligned multi-walled carbon nanotube array for removal of Escherichia coli O157:H7.

Science.gov (United States)

Oza, Goldie; Pandey, Sunil; Gupta, Arvind; Shinde, Sachin; Mewada, Ashmi; Jagadale, Pravin; Sharon, Maheshwar; Sharon, Madhuri

2013-10-01

A porous ceramic was coated with vertically aligned multi-walled carbon nanotubes (MWCNTs) by spray pyrolysis. Titanium dioxide (TiO2) nanoparticles were then coated onto this densely aligned MWCNT. The presence of TiO2/MWCNT interfacial arrays was confirmed by X-ray diffraction (XRD), scanning electron microscope-energy dispersive analysis of X-ray (SEM-EDAX) and transmission electron microscope (TEM). This is a novel report in which water loaded with a most dreadful enterohemorrhagic pathogenic strain of Escherichia coli O157:H7 was filtered through TiO2/MWCNT coated porous ceramic filter and then analysed. Bacterial removal performance was found to be significantly lower in control i.e. plain porous ceramic (Paligned MWCNT network. © 2013 Elsevier B.V. All rights reserved.

X-ray crystal structure and small-angle X-ray scattering of sheep liver sorbitol dehydrogenase

Energy Technology Data Exchange (ETDEWEB)

Yennawar, Hemant [Pennsylvania State University, 8 Althouse Laboratory, University Park, PA 16802 (United States); Møller, Magda [Cornell High Energy Synchrotron Source, Ithaca, NY 14853 (United States); University of Copenhagen, DK-2100 Copenhagen (Denmark); Gillilan, Richard [Cornell High Energy Synchrotron Source, Ithaca, NY 14853 (United States); Yennawar, Neela, E-mail: nhy1@psu.edu [Pennsylvania State University, 8 Althouse Laboratory, University Park, PA 16802 (United States)

2011-05-01

The X-ray crystal structure and a small-angle X-ray scattering solution structure of sheep liver sorbitol dehydrogenase have been determined. The details of the interactions that enable the tetramer scaffold to be the functional biological unit have been analyzed. The X-ray crystal structure of sheep liver sorbitol dehydrogenase (slSDH) has been determined using the crystal structure of human sorbitol dehydrogenase (hSDH) as a molecular-replacement model. slSDH crystallized in space group I222 with one monomer in the asymmetric unit. A conserved tetramer that superposes well with that seen in hSDH (despite belonging to a different space group) and obeying the 222 crystal symmetry is seen in slSDH. An acetate molecule is bound in the active site, coordinating to the active-site zinc through a water molecule. Glycerol, a substrate of slSDH, also occupies the substrate-binding pocket together with the acetate designed by nature to fit large polyol substrates. The substrate-binding pocket is seen to be in close proximity to the tetramer interface, which explains the need for the structural integrity of the tetramer for enzyme activity. Small-angle X-ray scattering was also used to identify the quaternary structure of the tetramer of slSDH in solution.

The effect of soil management on the persistence of E. coli and Listeria spp. in manure- amended soils in the Northeast United States

Science.gov (United States)

Introduction: Enterohemorrhagic Escherichia coli and Listeria monocytogenes can contaminate leafy greens through inappropriately managed raw manure applied to soils. Current FDA guidance includes calling for additional scientific data to determine the appropriate interval between application of man...

Occurrence and characterization of Shiga toxin-producing Escherichia coli O157:H7 and other non-sorbitol-fermenting E. coli in cattle and humans in urban areas of Morogoro, Tanzania

DEFF Research Database (Denmark)

Lupindu, Athumani M; Olsen, John Elmerdahl; Ngowi, Helena A

2014-01-01

Escherichia coli strains such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli, enterotoxigenic, attaching, and effacing E. coli, and enteroinvasive E. coli cause diarrhea in humans. Although other serotypes exist, the most commonly reported STEC in outbreaks is O157:H7. A cross-...

Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

Science.gov (United States)

Yang, Shih-Chun; Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

2017-08-01

Food contamination by pathogenic microorganisms has been a serious public health problem and a cause of huge economic losses worldwide. Foodborne pathogenic Escherichia coli (E. coli) contamination, such as that with E. coli O157 and O104, is very common, even in developed countries. Bacterial contamination may occur during any of the steps in the farm-to-table continuum from environmental, animal, or human sources and cause foodborne illness. To understand the causes of the foodborne outbreaks by E. coli and food-contamination prevention measures, we collected and investigated the past 10 years' worldwide reports of foodborne E. coli contamination cases. In the first half of this review article, we introduce the infection and symptoms of five major foodborne diarrheagenic E. coli pathotypes: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli/enterohemorrhagic E. coli (STEC/EHEC), Shigella/enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC). In the second half of this review article, we introduce the foodborne outbreak cases caused by E. coli in natural foods and food products. Finally, we discuss current developments that can be applied to control and prevent bacterial food contamination.

Lactase Non-Persistence Genotyping: Comparison of Two Real-Time PCR Assays and Assessment of Concomitant Fructose/Sorbitol Malabsorption Rates.

Science.gov (United States)

Enko, Dietmar; Pollheimer, Verena; Németh, Stefan; Pühringer, Helene; Stolba, Robert; Halwachs-Baumann, Gabriele; Kriegshäuser, Gernot

2016-01-01

Genetic testing is a standard technique for the diagnosis of primary adult-type hypolactasia, also referred to as lactase non-persistence. The aim of this study was to compare the lactase gene (LCT) C/T-13910 polymorphism genotyping results of two commercially available real-time (RT)-PCR assays in patients referred to our outpatient clinic for primary lactose malabsorption testing. Furthermore, concomitant conditions of fructose/sorbitol malabsorption were assessed. Samples obtained from 100 patients were tested in parallel using the LCT T-13910C ToolSet for Light Cycler (Roche, Rotkreuz, Switzerland) and the LCT-13910C>T RealFast Assay (ViennaLab Diagnostics GmbH, Vienna, Austria). Additionally, patients were also screened for the presence of fructose/sorbitol malabsorption by functional hydrogen (H2)/methane (CH4) breath testing (HMBT). Cohen's Kappa (κ) was used to calculate the agreement between the two genotyping methods. The exact Chi-Square test was performed to compare fructose/sorbitol HMBT with LCT genotyping results. Twenty-one (21.0%) patients had a LCT C/C-13910 genotype suggestive of lactase non-persistence, and 79 (79.0%) patients were identified with either a LCT T/C-13910 or T/T-13910 genotype (i.e., lactase persistence). In all genotype groups, concordance between the two RT-PCR assays was 100%. Cohen's κ demonstrated perfect observed agreement (p sorbitol malabsorption was observed in 13/100 (13.0%) and 25/100 (25.0%) individuals, respectively. Both RT-PCR assays are robust and reliable LCT genotyping tools in a routine clinical setting. Concomitant fructose and/or sorbitol malabsorption should be considered in individuals with suspected lactase-non-persistence. However, standardization of clinical interpretation of laboratory HMBT results is required.

Kombucha fermentation and its antimicrobial activity.

Science.gov (United States)

Sreeramulu, G; Zhu, Y; Knol, W

2000-06-01

Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the "tea fungus" and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacterpylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha.

Placental and colostral transfer of antibodies reactive with enteropathogenic Escherichia coli intimins α, β, or γ

Directory of Open Access Journals (Sweden)

Silvia P.N. Altman

2017-11-01

Full Text Available Objective: Intimins are protein adhesins of enteropathogenic Escherichia coli and enterohemorrhagic E. coli capable of inducing attachment and effacement lesions in enterocytes. Anti-intimin antibodies are important for the protection from enteropathogenic E. coli and enterohemorrhagic E. coli infections because these antibodies inhibit bacterial adhesion and impair the initial step of the pathogenesis. We studied the transfer of maternal anti-intimin antibodies from healthy Brazilian mothers to their newborns through the placenta and colostrum. Methods: Serum immunoglobulin G and secretory immunoglobulin A antibodies against conserved and variable regions of intimins α, β, and γ were analyzed using an enzyme linked-immunosorbent assay in the blood and colostrum from 45 healthy women as well as cord blood serum samples from their newborns. Results: The concentrations of antibodies reactive with α intimin were significantly lower than those of anti-γ and anti-conserved intimin antibodies in the colostrum samples. IgG serum antibodies reactive with all the subtypes of intimins were transferred to the newborns, but the concentrations of anti-conserved intimin serum antibodies were significantly higher in mothers and newborns than concentrations of antibodies against variable regions. The patterns of IgG transfer from mothers to newborns were similar for all anti-intimin antibodies. These values are similar to the percentage transference of total IgG. Conclusions: Anti-intimin antibodies are transferred from mothers to newborns through the placenta, and reinforce the protection provided by breastfeeding against diarrheagenic E. coli infections. Resumo: Objetivo: As Intiminas são adesinas proteicas de Escherichia coli enteropatogênicas e enterohemorrágicas capazes de induzir as lesões “attaching and effacing” nos enterócitos. Anticorpos anti-intiminas são importantes para a proteção contra infecções por E. coli enteropatogênica e

Structural characterization of the thermostable Bradyrhizobium japonicumD-sorbitol dehydrogenase.

Science.gov (United States)

Fredslund, Folmer; Otten, Harm; Gemperlein, Sabrina; Poulsen, Jens Christian N; Carius, Yvonne; Kohring, Gert Wieland; Lo Leggio, Leila

2016-11-01

Bradyrhizobium japonicum sorbitol dehydrogenase is NADH-dependent and is active at elevated temperatures. The best substrate is D-glucitol (a synonym for D-sorbitol), although L-glucitol is also accepted, giving it particular potential in industrial applications. Crystallization led to a hexagonal crystal form, with crystals diffracting to 2.9 Å resolution. In attempts to phase the data, a molecular-replacement solution based upon PDB entry 4nbu (33% identical in sequence to the target) was found. The solution contained one molecule in the asymmetric unit, but a tetramer similar to that found in other short-chain dehydrogenases, including the search model, could be reconstructed by applying crystallographic symmetry operations. The active site contains electron density consistent with D-glucitol and phosphate, but there was not clear evidence for the binding of NADH. In a search for the features that determine the thermostability of the enzyme, the T m for the orthologue from Rhodobacter sphaeroides, for which the structure was already known, was also determined, and this enzyme proved to be considerably less thermostable. A continuous β-sheet is formed between two monomers in the tetramer of the B. japonicum enzyme, a feature not generally shared by short-chain dehydrogenases, and which may contribute to thermostability, as may an increased Pro/Gly ratio.

Survival of Five Strains of Shiga Toxigenic Escherichia coli in a Sausage Fermentation Model and Subsequent Sensitivity to Stress from Gastric Acid and Intestinal Fluid

Directory of Open Access Journals (Sweden)

Tone Mari Rode

2017-01-01

Full Text Available The ability of foodborne pathogens to exhibit adaptive responses to stressful conditions in foods may enhance their survival when passing through the gastrointestinal system. We aimed to determine whether Escherichia coli surviving stresses encountered during a model dry-fermented sausage (DFS production process exhibit enhanced tolerance and survival in an in vitro gastrointestinal model. Salami sausage batters spiked with five E. coli isolates, including enterohaemorrhagic E. coli strains isolated from different DFS outbreaks, were fermented in a model DFS process (20°C, 21 days. Control batters spiked with the same strains were stored at 4°C for the same period. Samples from matured model sausages and controls were thereafter exposed to an in vitro digestion challenge. Gastric exposure (pH 3 resulted in considerably reduced survival of the E. coli strains that had undergone the model DFS process. This reduction continued after entering intestinal challenge (pH 8, but growth resumed after 120 min. When subjected to gastric challenge for 120 min, E. coli that had undergone the DFS process showed about 2.3 log10⁡​ lower survival compared with those kept in sausage batter at 4°C. Our results indicated that E. coli strains surviving a model DFS process exhibited reduced tolerance to subsequent gastric challenge at low pH.

Amino acids production focusing on fermentation technologies – A review

DEFF Research Database (Denmark)

D'Este, Martina; Alvarado-Morales, Merlin; Angelidaki, Irini

2018-01-01

Amino acids are attractive and promising biochemicals with market capacity requirements constantly increasing. Their applicability ranges from animal feed additives, flavour enhancers and ingredients in cosmetic to specialty nutrients in pharmaceutical and medical fields. This review gives...... an overview of the processes applied for amino acids production and points out the main advantages and disadvantages of each. Due to the advances made in the genetic engineering techniques, the biotechnological processes, and in particular the fermentation with the aid of strains such as Corynebacterium...... glutamicum or Escherichia coli, play a significant role in the industrial production of amino acids. Despite the numerous advantages of the fermentative amino acids production, the process still needs significant improvements leading to increased productivity and reduction of the production costs. Although...

Fructose and/or Sorbitol Intolerance in a Subgroup of Lactose Intolerant Patients

Directory of Open Access Journals (Sweden)

SR Mishkin

1994-01-01

Full Text Available The diagnosis and treatment of lactose intolerance often does not resolve all the symptoms of postcibal bloating and flatulence. Included in this study were 104 lactose intolerant patients (71 female, 33 male who complained of residual postcibal discomfort in spite of adherence to and benefit from appropriate measures for their documented lactose intolerance (at least 20 ppm H2 after 25 g lactose as well as appropriate symptomatic discomfort. Clinical characteristics common to this group included: symptomatic diarrhea (12.5%, history of foreign travel (5.8%, endoscopic and pathological evidence of gastritis and helicobacter infection (19.2 and 8.7%, respectively, nonspecific abnormalities of small bowel follow-through (15.4%, Crohn’s disease (8.7% and colonic cliverticulosis (14.4%. Intolerance co fructose (at least 10 ppm H2 after 25 g fructose plus appropriate symptoms or sorbitol (at least 10 ppm H2 after 5 g sorbitol plus appropriate symptoms was documented in 17.3 and 18.3%, respectively. Intolerance to both fructose and sorbicol (administered as separate challenges, more than twice as common as intolerance to either one alone, occurred in 41.4% and was independent of sex. In conclusion, additional carbohydrate intolerances contribute to postcibal discomfort in more than 75% of lactose intolerant patients who remain symptomatic in spite of adherence to appropriate measures for this condition. While 62% of all patients had benefited significantly (greater than 50% from appropriate dietary measures and enzyme replacement for lactose intolerance, only 40% of those who were also fructose intolerant and 47% who were sorbitol intolerant benefited (greater than 50% from appropriate dietary measures (no enzyme replacement yet available for intolerance to these sugars.

Comparison of the fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages.

Science.gov (United States)

Balamurugan, S; Ahmed, Rafath; Gao, Anli; Strange, Phil

2017-10-16

The study examined the relative fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages (DFS). Three separate batches of sausages containing a five-strain cocktail for each serogroup and uninoculated control were manufactured and subjected to identical fermentation, maturation and dry curing conditions. Changes in physicochemical properties and inoculated STEC numbers were enumerated during the DFS production stages and log reduction and log reduction rates were calculated. Inoculation of very high concentrations (8logCFUg -1 ) of STEC in the sausage batter did not significantly (P>0.05) affect the changes in the pH, a w , moisture, protein, fat content compared to the uninoculated DFS. There was a significant (P0.05) from each other. These results indicate that the lethality of DFS production processes observed against E. coli O157:H7 would result in a similar inactivation of the top six non-O157 STEC. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Erythritol Is More Effective Than Xylitol and Sorbitol in Managing Oral Health Endpoints

Directory of Open Access Journals (Sweden)

Peter de Cock

2016-01-01

Full Text Available Objective. To provide a comprehensive overview of published evidence on the impact of erythritol, a noncaloric polyol bulk sweetener, on oral health. Methods. A literature review was conducted regarding the potential effects of erythritol on dental plaque (biofilm, dental caries, and periodontal therapy. The efficacy of erythritol on oral health was compared with xylitol and sorbitol. Results. Erythritol effectively decreased weight of dental plaque and adherence of common streptococcal oral bacteria to tooth surfaces, inhibited growth and activity of associated bacteria like S. mutans, decreased expression of bacterial genes involved in sucrose metabolism, reduced the overall number of dental caries, and served as a suitable matrix for subgingival air-polishing to replace traditional root scaling. Conclusions. Important differences were reported in the effect of individual polyols on oral health. The current review provides evidence demonstrating better efficacy of erythritol compared to sorbitol and xylitol to maintain and improve oral health.

Pt nanocatalysts supported on reduced graphene oxide for selective conversion of cellulose or cellobiose to sorbitol.

Science.gov (United States)

Wang, Ding; Niu, Wenqi; Tan, Minghui; Wu, Mingbo; Zheng, Xuejun; Li, Yanpeng; Tsubaki, Noritatsu

2014-05-01

Pt nanocatalysts loaded on reduced graphene oxide (Pt/RGO) were prepared by means of a convenient microwave-assisted reduction approach with ethylene glycol as reductant. The conversion of cellulose or cellobiose into sorbitol was used as an application reaction to investigate their catalytic performance. Various metal nanocatalysts loaded on RGO were compared and RGO-supported Pt exhibited the highest catalytic activity with 91.5 % of sorbitol yield from cellobiose. The catalytic performances of Pt nanocatalysts supported on different carbon materials or on silica support were also compared. The results showed that RGO was the best catalyst support, and the yield of sorbitol was as high as 91.5 % from cellobiose and 58.9 % from cellulose, respectively. The improvement of catalytic activity was attributed to the appropriate Pt particle size and hydrogen spillover effect of Pt/RGO catalyst. Interestingly, the size and dispersion of supported Pt particles could be easily regulated by convenient adjustment of the microwave heating temperature. The catalytic performance was found to initially increase and then decrease with increasing particle size. The optimum Pt particle size was 3.6 nm. These findings may offer useful guidelines for designing novel catalysts with beneficial catalytic performance for biomass conversion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A polyclonal antibody based immunoassay detects seven subtypes of Shiga toxin 2 produced by Escherichia coli in human and environmental samples.

Directory of Open Access Journals (Sweden)

Xiaohua He

Full Text Available BACKGROUND: Shiga toxin-producing Escherichia coli (STEC are frequent causes of severe human diseases ranging from diarrhea to hemolytic uremic syndrome. The existing strategy for detection of STEC relies on the unique sorbitol-negative fermentation property of the O157 strains, the most commonly identified serotype has been E. coli O157. It is becoming increasingly evident, however, that numerous non-O157 STEC serotypes also cause outbreaks and severe illnesses. It is necessary to have new methods that are capable of detecting all STEC strains. METHODS AND FINDINGS: Here we describe the development of a sandwich ELISA assay for detecting both O157 and non-O157 STECs by incorporating a novel polyclonal antibody (pAb against Stx2. The newly established immunoassay was capable of detecting Stx2a spiked in environmental samples with a limit of detection between 10 and 100 pg/mL in soil and between 100 and 500 pg/mL in feces. When applied to 36 bacterial strains isolated from human and environmental samples, this assay detected Stx2 in all strains that were confirmed to be stx2-positive by real-time PCR, demonstrating a 100% sensitivity and specificity. CONCLUSIONS: The sandwich ELISA developed in this study will enable any competent laboratory to identify and characterize Stx2-producing O157 and non-O157 strains in human and environmental samples, resulting in rapid diagnosis and patient care. The results of epitope mapping from this study will be useful for further development of a peptide-based antibody and vaccine.

One-pot aqueous phase catalytic conversion of sorbitol to gasoline over nickel catalyst

International Nuclear Information System (INIS)

Weng, Yujing; Qiu, Songbai; Xu, Ying; Ding, Mingyue; Chen, Lungang; Zhang, Qi; Ma, Longlong; Wang, Tiejun

2015-01-01

Highlights: • Directly production gasoline (C5–C12 alkanes) from biomass-derived sugar alcohol sorbitol. • Temperature of STG (553–593 K) was lower than that of traditional methanol to gasoline (MTG) (623–773 K). • Gasoline yield of 46.9% and C7–C12 hydrocarbons reached up to 45.5% in the gasoline products. - Abstract: The carbon chain extension and hydrodeoxygenation steps play critical roles in the high-energy-density hydrocarbons production. In this paper, a systematic study had been carried out to investigate one-pot aqueous phase catalytic conversion of sorbitol to gasoline (STG) over bifunctional Ni-based catalysts. Characterization technologies of N 2 physisorption, X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and NH 3 temperature-programmed desorption (NH 3 -TPD) were used to study the textural properties, phase compositions, acid behavior and morphologies of the catalysts. The catalytic performances were tested in a fixed bed reactor. It was found that the physically mixed Ni/HZSM-5 and Ni/silica-gel (mesoporous SG) catalyst realized the carbon chain extension and exhibited excellent performances on hydrodeoxygenation (HDO) reaction (46.9% of gasoline (C5–C12) yield and 45.5% of C7–C12 hydrocarbons in the gasoline products). Especially, the temperature of STG (553–593 K) was lower obviously than that of the traditional methanol to gasoline (MTG) process (623–773 K). It provided a novel transformation of sorbitol to long-chain alkanes by one-pot process over the bifunctional catalyst (Ni@HZSM-5/SG), wherein hydrodeoxygenation, ketonization and aldol condensation steps were integrated

Survival of Escherichia coli O157:H7 in needle-tenderized dry cured Westphalian ham.

Science.gov (United States)

Graumann, Gary H; Holley, Richard A

2007-09-15

Westphalian ham is a dry cured, ready-to-eat product that is manufactured without a lethal heat treatment. Hams are preserved by a process that involves curing, fermenting, smoking and drying, which may take 3 months or more to complete. The process can be accelerated by tenderizing the meat with solid needles, to increase the rate of cure-salt diffusion throughout muscle tissues. In this study, intact hams were immersed in a solution containing a five strain cocktail of Escherichia coli O157:H7 at 8 log cfu/mL, to determine whether needle treatment before cure application would internalize organisms from the surface. In two trials, the survival of E. coli O157:H7 on external surfaces and within deep tissues after needle treatment was followed during the ripening of hams. The injured E. coli O157:H7 cells were recovered by plating samples on pre-poured Tryptic Soy Agar plates which were incubated for 3 to 4 h at 35 degrees C, overlaid with Sorbitol MacConkey Agar containing cefixime and tellurite and re-incubated at 35 degrees C for 48 to 72 h. Inoculated-injected hams initially carried E. coli O157:H7 at numbers of 7.3 and 4.6 log cfu/g E. coli O157:H7 on the surface and inside, respectively. After 112 d of ripening, which included 79 d of drying, no E. coli O157:H7 were detected at the surface of hams following enrichment, whereas in deep tissue the organism was recovered at numbers of 3.1 log cfu/g. The Westphalian ham ripening procedure evidently was not adequate to eliminate E. coli O157:H7 internalized by needle tenderization.

Conversion of biomass-derived sorbitol to glycols over carbon-materials supported Ru-based catalysts

Science.gov (United States)

Guo, Xingcui; Guan, Jing; Li, Bin; Wang, Xicheng; Mu, Xindong; Liu, Huizhou

2015-11-01

Ruthenium (Ru) supported on activated carbon (AC) and carbon nanotubes (CNTs) was carried out in the hydrogenolysis of sorbitol to ethylene glycol (EG) and 1,2-propanediol (1,2-PD) under the promotion of tungsten (WOx) species and different bases. Their catalytic activities and glycols selectivities strongly depended on the support properties and location of Ru on CNTs, owning to the altered metal-support interactions and electronic state of ruthenium. Ru located outside of the tubes showed excellent catalytic performance than those encapsulated inside the nanotubes. Additionally, the introduction of WOx into Ru/CNTs significantly improved the hydrogenolysis activities, and a complete conversion of sorbitol with up to 60.2% 1,2-PD and EG yields was obtained on RuWOx/CNTs catalyst upon addition of Ca(OH)2. Stability study showed that this catalyst was highly stable against leaching and poisoning and could be recycled several times.

Simultaneous hydrolysis and hydrogenation of cellobiose to sorbitol in molten salt hydrate media

NARCIS (Netherlands)

Li, J.; Soares, H.S.M.P.; Moulijn, J.A.; Makkee, M.

2013-01-01

The hydrolysis and hydrogenation of cellobiose (4-O-b-D-glucopyranosyl-D-glucose) in ZnCl2_4H2O solvent was studied to optimize the conditions for conversion of lignocellulose (the most abundant renewable resource) into sorbitol (D-glucitol). Water at neutral pH does not allow hydrolysis of

Preparation and Characterization of HPMC/PVP Blend Films Plasticized with Sorbitol

OpenAIRE

Somashekarappa, H.; Prakash, Y.; Hemalatha, K.; Demappa, T.; Somashekar, R.

2013-01-01

The aim of this present work is to investigate the effect of plasticizers like Sorbitol on microstructural and mechanical properties of hydroxypropyl methylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) blend films. The pure blend and plasticized blend films were prepared by solution casting method and investigated using wide angle X-ray scattering (WAXS) method. WAXS analysis confirms that the plasticizers can enter into macromolecular blend structure and destroy the crystallinity of the f...

Isolation of Lactic Acid Bacteria with High Biological Activity from Local Fermented Dairy Products

OpenAIRE

B. Munkhtsetseg; M. Margad-Erdene; B. Batjargal

2009-01-01

The thirty-two strains of lactic acid bacteria were isolated from the Mongolian traditional fermented dairy products, among them 25 strains show antimicrobial activity against test microorganisms including Escherichia coli , Staphylococcus aureus , Enterococcus faecalis , Pseudom о nas aeruginosa . Protease sensitivity assay demonstrated that the antimicrobial substances produced by isolates А 23, Т 2 are bacterio...

Reproducible Biofilm Cultivation of Chemostat-Grown Escherichia coli and Investigation of Bacterial Adhesion on Biomaterials Using a Non-Constant-Depth Film Fermenter

Science.gov (United States)

Lüdecke, Claudia; Jandt, Klaus D.; Siegismund, Daniel; Kujau, Marian J.; Zang, Emerson; Rettenmayr, Markus; Bossert, Jörg; Roth, Martin

2014-01-01

Biomaterials-associated infections are primarily initiated by the adhesion of microorganisms on the biomaterial surfaces and subsequent biofilm formation. Understanding the fundamental microbial adhesion mechanisms and biofilm development is crucial for developing strategies to prevent such infections. Suitable in vitro systems for biofilm cultivation and bacterial adhesion at controllable, constant and reproducible conditions are indispensable. This study aimed (i) to modify the previously described constant-depth film fermenter for the reproducible cultivation of biofilms at non-depth-restricted, constant and low shear conditions and (ii) to use this system to elucidate bacterial adhesion kinetics on different biomaterials, focusing on biomaterials surface nanoroughness and hydrophobicity. Chemostat-grown Escherichia coli were used for biofilm cultivation on titanium oxide and investigating bacterial adhesion over time on titanium oxide, poly(styrene), poly(tetrafluoroethylene) and glass. Using chemostat-grown microbial cells (single-species continuous culture) minimized variations between the biofilms cultivated during different experimental runs. Bacterial adhesion on biomaterials comprised an initial lag-phase I followed by a fast adhesion phase II and a phase of saturation III. With increasing biomaterials surface nanoroughness and increasing hydrophobicity, adhesion rates increased during phases I and II. The influence of materials surface hydrophobicity seemed to exceed that of nanoroughness during the lag-phase I, whereas it was vice versa during adhesion phase II. This study introduces the non-constant-depth film fermenter in combination with a chemostat culture to allow for a controlled approach to reproducibly cultivate biofilms and to investigate bacterial adhesion kinetics at constant and low shear conditions. The findings will support developing and adequate testing of biomaterials surface modifications eventually preventing biomaterial

Potential of fermented papaya beverage in the prevention of foodborne illness incidence

Directory of Open Access Journals (Sweden)

Koh, S.P.

2017-05-01

Full Text Available Foodborne illness is recognized as an emerging infectious disease. The incidence of foodborne infections is common and the majority cases are undiagnosed or unreported. Apart from some diarrhea or minor gastrointestinal problem, some foodborne pathogenic microbes may cause death, particularly to those people with weakened immune system. In this study, we have developed a new fermented papaya beverage using symbiotic culture of yeast and acetic acid bacteria under controlled biofermentation process. An in-vitro assessment of fermented papaya beverage against few foodborne pathogenic microorganism was conducted to determine its minimum bactericidal concentration (MBC>99. Three types of foodborne pathogen: Escherichia coli O157, Salmonella enterica serovar Typhimurium ATCC 53648, Salmonella enterica serovar Enteritidis (isolated from infectious chicken were selected. From minimum bactericidal concentration (MBC>99 assay, both fermented papaya pulp and leaves beverages have shown 100% killing rate against three selected foodborne pathogenic microbes. Inversely, non-fermented papaya pulp and leaves beverages indicated no inhibition at all. In fact, further dilution of fermented papaya pulp and leaves beverages demonstrated different degree of MBC>99 and brix value, but the pH value remained less than 3.5. These findings indicated the combination of soluble solid compounds presents in both fermented papaya beverage and product acidity play an important role in the inhibition of pathogenic microorganisms. The preliminary promising results of this work have shown that the great potential of fermented papaya beverages as a preventive measure to reduce the incidence of foodborne illness.

Peptidoglycan from Fermentation By-Product Triggers Defense Responses in Grapevine

Science.gov (United States)

Chen, Yang; Takeda, Taito; Aoki, Yoshinao; Fujita, Keiko; Suzuki, Shunji; Igarashi, Daisuke

2014-01-01

Plants are constantly under attack from a variety of microorganisms, and rely on a series of complex detection and response systems to protect themselves from infection. Here, we found that a by-product of glutamate fermentation triggered defense responses in grapevine, increasing the expression of defense response genes in cultured cells, foliar chitinase activity, and resistance to infection by downy mildew in leaf explants. To identify the molecule that triggered this innate immunity, we fractionated and purified candidates extracted from Corynebacterium glutamicum, a bacterium used in the production of amino acids by fermentation. Using hydrolysis by lysozyme, a silkworm larva plasma detection system, and gel filtration analysis, we identified peptidoglycan as inducing the defense responses. Peptidoglycans of Escherichia coli, Bacillus subtilis, and Staphylococcus aureus also generated similar defensive responses. PMID:25427192

Dose response of xylitol and sorbitol for epr retrospective dosimetry with applications to chewing gum

International Nuclear Information System (INIS)

Israelsson, A.; Gustafsson, H.; Lund, E.

2013-01-01

The purpose of this investigation was to study the radiation-induced electron paramagnetic resonance signal in sweeteners xylitol and sorbitol for use in retrospective dosimetry. For both sweeteners and chewing gum, the signal changed at an interval of 1-84 d after irradiation with minimal changes after 4-8 d. A dependence on storage conditions was noticed and the exposure of the samples to light and humidity was therefore minimised. Both the xylitol and sorbitol signals showed linearity with dose in the measured dose interval, 0-20 Gy. The dose-response measurements for the chewing gum resulted in a decision threshold of 0.38 Gy and a detection limit of 0.78 Gy. A blind test illustrated the possibility of using chewing gums as a retrospective dosemeter with an uncertainty in the dose determination of 0.17 Gy (1 SD). (authors)

Yersinia enterocolitica in fermented sausages

Science.gov (United States)

Mitrović, R.; Janković, V.; Baltić, B.; Ivanović, J.

2017-09-01

Different types of food, among them meat, can be the cause of food-borne diseases, and infections are commonly caused by Campylobacter, Salmonella, Yersinia enterocolitica, verotoxic Escherichia coli and Listeria monocytogenes. All these bacteria, depending on a number of factors, including animal species, geographical origin, climatic factors, methods of animal breeding and meat production, could cause disease. Here, we summarise results on production of different groups of sausages produced with or without added starter culture, and contaminated with Y.enterocolitica (control sausages were not contaminated). During the ripening, changes in the microbiological status of the fermented sausages and their physical and chemical properties were monitored. For all tests, standard methods were used. In these fermented sausages, the number of Y. enterocolitica decreased during ripening. The number of Y. enterocolitica was statistically significantly lower in sausages with added starter culture on all days of the study Zoonotic pathogens in meat should be controlled through the complete production chain, from the farms to consumers, in order to reduce the probability of disease in humans. However, the necessary controls in the production chain are not the same for all bacteria.

Outbreak of Non-O157 Shiga Toxin-Producing Escherichia coli Infection from Consumption of Beef Sausage

DEFF Research Database (Denmark)

Ethelberg, S.; Smith, B.; Torpdahl, M.

2009-01-01

We describe an outbreak of Shiga toxin-producing Escherichia coli O26: H11 infection in 20 patients (median age, 2 years). The source of the infection was an organic fermented beef sausage. The source was discovered by using credit card information to obtain and compare customer transaction records...

Antibacterial effect of lactoferricin B on Escherichia coli O157:H7 in ground beef.

Science.gov (United States)

Venkitanarayanan, K S; Zhao, T; Doyle, M P

1999-07-01

The antibacterial activity of lactoferricin B on enterohemorrhagic Escherichia coli O157:H7 in 1% peptone medium and ground beef was studied at 4 and 10 degrees C. In 1% peptone medium, 50 and 100 microg of lactoferricin B per ml reduced E. coli O157:H7 populations by approximately 0.7 and 2.0 log CFU/ml, respectively. Studies comparing the antibacterial effect of lactoferricin B on E. coli O157:H7 in 1% peptone at pH 5.5 and 7.2 did not reveal any significant difference (P > 0.5) at the two pH values. Lactoferricin B (100 microg/g) reduced E. coli O157:H7 population in ground beef by about 0.8 log CFU/g (P 0.5) was observed in the total plate count between treatment and control ground beef samples stored at 4 and 10 degrees C. The antibacterial effect of lactoferricin B on E. coli O157:H7 observed in this study is not of sufficient magnitude to merit its use in ground beef for controlling the pathogen.

From lin-Benzoguanines to lin-Benzohypoxanthines as Ligands for Zymomonas mobilis tRNA-Guanine Transglycosylase: Replacement of Protein-Ligand Hydrogen Bonding by Importing Water Clusters.

NARCIS (Netherlands)

Barandun, L.J.; Immekus, F.; Kohler, P.C.; Tonazzi, S.; Wagner, B.; Wendelspiess, S.; Ritschel, T.; Heine, A.; Kansy, M.; Klebe, G.; Diederich, F.

2012-01-01

The foodborne illness shigellosis is caused by Shigella bacteria that secrete the highly cytotoxic Shiga toxin, which is also formed by the closely related enterohemorrhagic Escherichia coli (EHEC). It has been shown that tRNA-guanine transglycosylase (TGT) is essential for the pathogenicity of

Behavior of Escherichia coli O157:H7 and Listeria monocytogenes during fermentation and storage of camel yogurt.

Science.gov (United States)

Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Ayyash, Mutamed M; Abushelaibi, Aisha; Jaradat, Ziad W; Shaker, Reyad; Al-Taani, Mahmoud; Holley, Richard A

2016-03-01

In addition to its nutritional and therapeutic properties, camel milk has the ability to suppress the growth of a wide range of foodborne pathogens, but there is a lack of information regarding the behavior of these pathogens in products such as yogurt produced from camel milk. The objective of the current study was to investigate the behavior of Listeria monocytogenes and Escherichia coli O157:H7 during manufacture and storage of camel yogurt. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 was fermented at 43° C for 5h using freeze-dried lactic acid bacteria (LAB) starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) and stored at 4 or 10 °C for 14 d. Camel milk inoculated with L. monocytogenes and E. coli O157:H7 without starter culture was also prepared. During fermentation, the numbers of L. monocytogenes and E. coli O157:H7 increased 0.3 and 1.6 log cfu/mL, respectively, in the presence of LAB, and by 0.3 and 2.7 log cfu/mL in the absence of LAB. During storage at 4 or 10 °C, L. monocytogenes increased 0.8 to 1.2 log cfu/mL by 14 d in camel milk without LAB, but in the presence of LAB, the numbers of L. monocytogenes were reduced by 1.2 to 1.7 log cfu/mL by 14 d. Further, E. coli O157:H7 numbers in camel milk were reduced by 3.4 to 3.5 log cfu/mL in the absence of LAB, but E. coli O157:H7 was not detected (6.3 log cfu/mL reduction) by 7d in camel yogurt made with LAB and stored at either temperature. Although camel milk contains high concentrations of natural antimicrobials, L. monocytogenes was able to tolerate these compounds in camel yogurt stored at refrigerator temperatures. Therefore, appropriate care should be taken during production of yogurt from camel milk to minimize the potential for postprocess contamination by this and other foodborne pathogens. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Directory of Open Access Journals (Sweden)

Paulo Díaz-Calderón

2015-12-01

Full Text Available El objetivo de este trabajo fue evaluar el efecto del sorbitol sobre la cinética de relajación estructural de películas de gelatina almacenadas bajo la temperatura de transición vítrea (Tg. Películas de gelatina de bovino y sorbitol fueron preparadas mediante casting en frío. El sorbitol fue agregado en fracciones en peso (Qs de 0,0, 0,06 y 0,10. Las películas fueron acondicionadas en un ambiente de humedad relativa constante (44% utilizando una solución saturada de carbonato de potasio, obteniéndose fracciones de contenido de humedad en peso (Qw de 0,18, 0,16 y 0,18 respectivamente. La entalpía de relajación (∆H fue determinada mediante Calorimetría Diferencial de Barrido (DSC. Las muestras utilizadas en este estudio presentaron valores de Tg de 48ºC (Qs=0,0, 35ºC (Qs=0,06 y 30ºC (Qs=0,10. Luego de eliminar el historial térmico (30ºC sobre Tg, 15min, las muestras fueron almacenadas isotérmicamente a 10ºC bajo Tgonset entre 2 y 80 horas. La adición de sorbitol produjo una reducción signifi cativa (p<0,05 en la cinética de relajación estructural. La linealización del valor de entalpía de relajación (∆H en función del logaritmo del tiempo de almacenamiento mostró una reducción de la pendiente en las muestras plastifi cadas con sorbitol. La reducción en la cinética de relajación estaría relacionada con el efecto de empaquetamiento molecular asociado a la presencia de polioles en matrices en estado vítreo recientemente reportada mediante espectroscopía de positrones (PALS

Amino acids production focusing on fermentation technologies - A review.

Science.gov (United States)

D'Este, Martina; Alvarado-Morales, Merlin; Angelidaki, Irini

Amino acids are attractive and promising biochemicals with market capacity requirements constantly increasing. Their applicability ranges from animal feed additives, flavour enhancers and ingredients in cosmetic to specialty nutrients in pharmaceutical and medical fields. This review gives an overview of the processes applied for amino acids production and points out the main advantages and disadvantages of each. Due to the advances made in the genetic engineering techniques, the biotechnological processes, and in particular the fermentation with the aid of strains such as Corynebacterium glutamicum or Escherichia coli, play a significant role in the industrial production of amino acids. Despite the numerous advantages of the fermentative amino acids production, the process still needs significant improvements leading to increased productivity and reduction of the production costs. Although the production processes of amino acids have been extensively investigated in previous studies, a comprehensive overview of the developments in bioprocess technology has not been reported yet. This review states the importance of the fermentation process for industrial amino acids production, underlining the strengths and the weaknesses of the process. Moreover, the potential of innovative approaches utilizing macro and microalgae or bacteria are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

Simultaneous separation and determination of fructose, sorbitol, glucose and sucrose in fruits by HPLC-ELSD.

Science.gov (United States)

Ma, Chunmei; Sun, Zhen; Chen, Changbao; Zhang, Lili; Zhu, Shuhua

2014-02-15

A high-performance liquid chromatography (HPLC) method with evaporative light scattering detection (ELSD) was optimised for simultaneous determination of fructose, sorbitol, glucose and sucrose in fruits. The analysis was carried out on a Phenomenex Luna 5u NH₂ 100A column (250 mm × 4.60mm, 5 micron) with isocratic elution of acetonitrile:water (82.5:17.5, v/v). Drift tube temperature of the ELSD system was set to 82 °C and nitrogen flow rate was 2.0 L min⁻¹. The regression equation revealed good linear relationship (R = 0.9967-0.9989) within test ranges. The limits of detection (LOD) and quantification (LOQ) for four analytes (peach, apple, watermelon, and cherry fruits) were in the range of 0.07-0.27 and 0.22-0.91 mg L⁻¹, respectively. The proposed HPLC-ELSD method was validated for quantification of sugars in peach, apple, watermelon, and cherry fruits, and the results were satisfactory. The results showed that the contents of the four sugars varied among fruits. While fructose (5.79-104.01 mg g⁻¹) and glucose (9.25-99.62 mg g⁻¹) emerged as common sugars in the four fruits, sorbitol (8.70-19.13 mg g⁻¹) were only found in peach, apple and cherry fruits, and sucrose (15.82-106.39 mg g⁻¹) were in peach, apple and watermelon. There was not detectable sorbitol in watermelon and sucrose in cherry fruits, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analise térmica e microscópica de laminados biodegradáveis obtidos a partir de farinha de mandioca, sorbitol e poli (butileno adipato co-tereftalato PBAT. Thermal and microscopic analysis of biodegradable laminates made from cassava flour, sorbitol and poly (butylene adipate-co-terephthalate PBAT - doi: 10.4025/actascitechnol.v35i4.13183

Directory of Open Access Journals (Sweden)

Henrique Tirolli Rett

2013-10-01

Full Text Available O objetivo deste trabalho foi desenvolver blendas de materiais laminados biodegradáveis, utilizando farinha de mandioca como fonte de amido, fibras naturais, sorbitol como plastificante e PBAT. Primeiro obteve-se peletes de três formulações diferentes e a partir destes, utilizou-se a termoprensagem a alta temperatura como alternativa na formação dos laminados. A caracterização foi feita através de microscopia eletrônica de varredura (MEV e calorimetria diferencia de varredura (CDV. A quantidade se sorbitol que melhor se ajustou à extrusão foi a de 15% (peso/peso; a formulação do laminado mais homogêneo, observada pela microscopia, foi de 55:40:15 (farinha/sorbitol/PBAT. As fibras ficaram dispersas por toda a superfície nos três tratamentos estudados, porém, por dentre eles, observaram-se zonas dispersas das fibras. Conforme se aumentou o teor de farinha, houve aumento no ponto de fusão dos laminados em comparação ao PBAT puro.Blends of biodegradable laminated materials were developed using cassava flour as starch and natural fibers source, sorbitol as a plasticizer and PBAT as a biodegradable polyester. After obtaining pellets from three different formulations, high temperature thermopressure was used to form laminates. The characterization was performed by scanning electron microscopy (SEM and by differential scanning calorimetry (DSC. The amount of sorbitol for the best extrusion process was 15% (weight/weight and the formulation of the best homogeneity observed by microscopy was 55:40:15 (flour/sorbitol/PBAT. Although fibers were dispersed throughout the surface in the three treatments, scattered areas of fibers could be found among them. As rates of flour increased, an increase in the melting point of the laminates occurred when compared to pure PBAT.  

Efficient soluble expression of disulfide bonded proteins in the cytoplasm of Escherichia coli in fed-batch fermentations on chemically defined minimal media.

Science.gov (United States)

Gąciarz, Anna; Khatri, Narendar Kumar; Velez-Suberbie, M Lourdes; Saaranen, Mirva J; Uchida, Yuko; Keshavarz-Moore, Eli; Ruddock, Lloyd W

2017-06-15

The production of recombinant proteins containing disulfide bonds in Escherichia coli is challenging. In most cases the protein of interest needs to be either targeted to the oxidizing periplasm or expressed in the cytoplasm in the form of inclusion bodies, then solubilized and re-folded in vitro. Both of these approaches have limitations. Previously we showed that soluble expression of disulfide bonded proteins in the cytoplasm of E. coli is possible at shake flask scale with a system, known as CyDisCo, which is based on co-expression of a protein of interest along with a sulfhydryl oxidase and a disulfide bond isomerase. With CyDisCo it is possible to produce disulfide bonded proteins in the presence of intact reducing pathways in the cytoplasm. Here we scaled up production of four disulfide bonded proteins to stirred tank bioreactors and achieved high cell densities and protein yields in glucose fed-batch fermentations, using an E. coli strain (BW25113) with the cytoplasmic reducing pathways intact. Even without process optimization production of purified human single chain IgA 1 antibody fragment reached 139 mg/L and hen avidin 71 mg/L, while purified yields of human growth hormone 1 and interleukin 6 were around 1 g/L. Preliminary results show that human growth hormone 1 was also efficiently produced in fermentations of W3110 strain and when glucose was replaced with glycerol as the carbon source. Our results show for the first time that efficient production of high yields of soluble disulfide bonded proteins in the cytoplasm of E. coli with the reducing pathways intact is feasible to scale-up to bioreactor cultivations on chemically defined minimal media.

A comparative study on cellulose nanocrystals extracted from bleached cotton and flax and used for casting films with glycerol and sorbitol plasticisers.

Science.gov (United States)

Csiszár, Emilia; Nagy, Sebestyén

2017-10-15

Cellulose nanocrystals (CNCs) were released from bleached cotton and flax by a sulphuric acid hydrolysis with about 40 and 34% yield, respectively. The rod-like cotton-CNC particles were slightly longer and wider and had a less pronounced aggregation ability in aqueous suspension than the flax-CNC ones. Films were cast from the CNC suspensions with sorbitol and glycerol plasticisers. The concept behind this research was to explore how the plasticisers - with similar structure but different molecular weight - and their concentrations affect the perceptible and measured properties of CNC films. Results revealed that the type of plasticiser determined the morphology and the optical and tensile properties of films. The best quality CNC film with an averaged thickness of 50μm was obtained with 20% sorbitol from cotton-CNC. It was proved that behaviour of sorbitol and glycerol plasticisers in CNC films was very similar to that reported previously for starch films. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surveillance of Virulence Markers and Antibiotic Resistance of Shiga toxin Producing E.coli O157:H7 Strains from Meats Purchase in Shiraz

Directory of Open Access Journals (Sweden)

Mohammad Kargar

2011-09-01

Full Text Available Background: Shiga toxin Producing Escherichia coli O157:H7 is a common pathogen in cattle, which occasional causes some human disease. This bacterium can potentially contaminate meat and clinical cases of E.coli O157:H7 infections are often associated with consumption of undercooked ground beef. Methods: In this cross-sectional study 122 samples of ground meat were collected and after enrichment in specific culture media and evaluation sorbitol fermentation and their β-glucoronidase activity, the isolation of E.coli O157:H7 strains have been confirmed with specific antisera. Then virulence genes verotoxin, intimin and hemolysin with multiplex PCR and antibiotic resistance strains with disk diffusion method have been tested. Results: Out of specimens that have been supplied, 119 sorbitol negative colonies isolated which 3 strains O157:H7 (2.45% with specific antisera confirmed. Out of considered virulence genes, in two cases of these samples (1.64% the stx1 and eaeA genes were seen and also 2 isolated bacteria had resistance to erythromycin, tetracycline, ampicillin, penicillin, clindamicin, cefixime, novobiocin, and gentamicin antibiotics. Conclusion: As this organism lives in intestines of healthy cattle, preventive measures on cattle farms and during meat processing are necessary.

A Novel Aqueous Micellar Two-Phase System Composed of Surfactant and Sorbitol for Purification of Pectinase Enzyme from Psidium guajava and Recycling Phase Components

Science.gov (United States)

Murshid, Fara Syazana; Manap, Mohd Yazid; Hussin, Muhaini

2015-01-01

A novel aqueous two-phase system composed of a surfactant and sorbitol was employed for the first time to purify pectinase from Psidium guajava. The influences of different parameters, including the type and concentration of the surfactant and the concentration and composition of the surfactant/sorbitol ratio, on the partitioning behavior and recovery of pectinase were investigated. Moreover, the effects of system pH and the crude load on purification fold and the yield of purified pectinase were studied. The experimental results indicated that the pectinase was partitioned into surfactant-rich top phase, and the impurities were partitioned into the sorbitol-rich bottom phase with the novel method involving an ATPS composed of 26% (w/w) Triton X-100 and 23% (w/w) sorbitol at 54.2% of the TLL crude load of 20% (w/w) at pH 6.0. The enzyme was successfully recovered by this method with a high purification factor of 15.2 and a yield of 98.3%, whereas the phase components were also recovered and recycled at rates above 96%. This study demonstrated that this novel ATPS method can be used as an efficient and economical alternative to the traditional ATPS for the purification and recovery of the valuable enzyme. PMID:25756051

A novel aqueous micellar two-phase system composed of surfactant and sorbitol for purification of pectinase enzyme from Psidium guajava and recycling phase components.

Science.gov (United States)

Amid, Mehrnoush; Murshid, Fara Syazana; Manap, Mohd Yazid; Hussin, Muhaini

2015-01-01

A novel aqueous two-phase system composed of a surfactant and sorbitol was employed for the first time to purify pectinase from Psidium guajava. The influences of different parameters, including the type and concentration of the surfactant and the concentration and composition of the surfactant/sorbitol ratio, on the partitioning behavior and recovery of pectinase were investigated. Moreover, the effects of system pH and the crude load on purification fold and the yield of purified pectinase were studied. The experimental results indicated that the pectinase was partitioned into surfactant-rich top phase, and the impurities were partitioned into the sorbitol-rich bottom phase with the novel method involving an ATPS composed of 26% (w/w) Triton X-100 and 23% (w/w) sorbitol at 54.2% of the TLL crude load of 20% (w/w) at pH 6.0. The enzyme was successfully recovered by this method with a high purification factor of 15.2 and a yield of 98.3%, whereas the phase components were also recovered and recycled at rates above 96%. This study demonstrated that this novel ATPS method can be used as an efficient and economical alternative to the traditional ATPS for the purification and recovery of the valuable enzyme.

Pharmaceutical protein production by yeast: towards production of human blood proteins by microbial fermentation

DEFF Research Database (Denmark)

Martinez Ruiz, José Luis; Liu, Lifang; Petranovic, Dina

2012-01-01

Since the approval of recombinant insulin from Escherichia coli for its clinical use in the early 1980s, the amount of recombinant pharmaceutical proteins obtained by microbial fermentations has significantly increased. The recent advances in genomics together with high throughput analysis...... of recombinant therapeutics using yeast Saccharomyces cerevisiae as a model platform, and discusses the future potential of this platform for production of blood proteins and substitutes....

Dynamics and diversity of microbial community succession in traditional fermentation of Shanxi aged vinegar.

Science.gov (United States)

Nie, Zhiqiang; Zheng, Yu; Du, Hongfu; Xie, Sankuan; Wang, Min

2015-05-01

The traditional fermentation of Shanxi aged vinegar (SAV), a well-known traditional Chinese vinegar, generally involves the preparation of starter daqu, starch saccharification, alcoholic fermentation (AF) and acetic acid fermentation (AAF). Dynamics and diversity of microbial community succession in daqu and other fermentation stages were investigated by denaturing gradient gel electrophoresis (DGGE). Results showed that eight bacterial genera and four fungal genera were found in daqu. However, Staphylococcus, Saccharopolyspora, Bacillus, Oceanobacillus, Enterobacter, Streptomyces, Eurotium, Monascus and Pichia in daqu were eradicated during AF. Four bacterial genera and three fungal genera were found in this stage. Weissella, Lactobacillus, Streptococcus, Saccharomyces, and Saccharomycopsis were the dominant microorganisms in the late stage of AF. During AAF, four bacterial genera and four fungal genera were found. Weissella, Streptococcus, Klebsiella, Escherichia, and Cladosporium gradually disappeared; the dominant microorganisms were Acetobacter, Lactobacillus, Saccharomycopsis, and Alternaria in the late stage of AAF. Alpha diversity metrics showed that fungal diversity in daqu was greater than that in AF and AAF. By contrast, bacterial diversity decreased from daqu to AF and increased in the first three days of AAF and then decreased. Hence, these results could help understand dynamics of microbial community succession in continuous fermentation of traditional Chinese vinegars. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid conversion of sorbitol to isosorbide in hydrophobic ionic liquids under microwave irradiation.

Science.gov (United States)

Kamimura, Akio; Murata, Kengo; Tanaka, Yoshiki; Okagawa, Tomoki; Matsumoto, Hiroshi; Kaiso, Kouji; Yoshimoto, Makoto

2014-12-01

Sorbitol was effectively converted to isosorbide by treatment with [TMPA][NTf2 ] in the presence of catalytic amounts of TsOH under microwave heating at 180 °C. The reaction completed within 10 min and isosorbide was isolated to about 60%. Ionic liquids were readily recovered by an extraction treatment and reused several times. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of ethanol from thin stillage by metabolically engineered Escherichia coli.

Science.gov (United States)

Gonzalez, Ramon; Campbell, Paul; Wong, Matthew

2010-03-01

Thin stillage is a by-product generated in large amounts during the production of ethanol that is rich in carbon sources like glycerol, glucose and maltose. Unfortunately, the fermentation of thin stillage results in a mixture of organic acids and ethanol and minimum utilization of glycerol, the latter a compound that can represent up to 80% of the available substrates in this stream. We report here the efficient production of ethanol from thin stillage by a metabolically engineered strain of Escherichia coli. Simultaneous utilization of glycerol and sugars was achieved by overexpressing either the fermentative or the respiratory glycerol-utilization pathway. However, amplification of the fermentative pathway (encoded by gldA and dhaKLM) led to more efficient consumption of glycerol and promoted the synthesis of reduced products, including ethanol. A previously constructed strain, EH05, containing mutations that prevented the accumulation of competing by-products (i.e. lactate, acetate, and succinate) and overexpressing the fermentative pathway for glycerol utilization [i.e. strain EH05 (pZSKLMgldA)], efficiently converted thin stillage supplemented with only mineral salts to ethanol at yields close to 85% of the theoretical maximum. Ethanol accounted for about 90% (w/w) of the product mixture. These results, along with the comparable performance of strain EH05 (pZSKLMgldA) in 0.5 and 5 l fermenters, indicate a great potential for the adoption of this process by the biofuels industry.

Increased Furfural Tolerance Due to Overexpression of NADH-Dependent Oxidoreductase FucO in Escherichia coli Strains Engineered for the Production of Ethanol and Lactate▿

OpenAIRE

Wang, X.; Miller, E. N.; Yomano, L. P.; Zhang, X.; Shanmugam, K. T.; Ingram, L. O.

2011-01-01

Furfural is an important fermentation inhibitor in hemicellulose sugar syrups derived from woody biomass. The metabolism of furfural by NADPH-dependent oxidoreductases, such as YqhD (low Km for NADPH), is proposed to inhibit the growth and fermentation of xylose in Escherichia coli by competing with biosynthesis for NADPH. The discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural provided a new approach to improve furfural tolerance. Strains that produced eth...

Intracellular trehalose and sorbitol synergistically promoting cell viability of a biocontrol yeast, Pichia anomala, for aflatoxin reduction.

Science.gov (United States)

Hua, Sui Sheng T; Hernlem, Bradley J; Yokoyama, Wallace; Sarreal, Siov Bouy L

2015-05-01

Pichia anomala (Wickerhamomyces anomalus) WRL-076 was discovered by a visual screening bioassay for its antagonism against Aspergillus flavus. The yeast was shown to significantly inhibit aflatoxin production and the growth of A. flavus. P. anomala is a potential biocontrol agent for reduction of aflatoxin in the food chain. Maintaining the viability of biocontrol agents in formulated products is a great challenge for commercial applications. Four media, NYG, NYGS, NYGT and NYGST are described which support good growth of yeast cells and were tested as storage formulations. Post growth supplement of 5 % trehalose to NYGST resulted in 83 % viable yeast cells after 12 months in cold storage. Intracellular sorbitol and trehalose concentrations were determined by HPLC analysis at the beginning of the storage and at the end of 12 month. Correlation of cell viability to both trehalose and sorbitol suggested a synergistic effect. Bonferroni (Dunn) t Test, Tukey's Studentized Range (HSD) Test and Duncan's Multiple Range Test, all showed that yeast cell viability in samples with both intracellular trehalose and sorbitol were significantly higher than those with either or none, at a 95 % confidence level. DiBAC4(5) and CFDA-AM were used as the membrane integrity fluorescent stains to create a two-color vital staining scheme with red and green fluorescence, respectively. Yeast cells stored in formulations NYG and NYGS with no detectable trehalose, displayed mostly red fluorescence. Yeast cells in NYGST+5T showed mostly green fluorescence.

Freeze-dried snake antivenoms formulated with sorbitol, sucrose or mannitol: comparison of their stability in an accelerated test.

Science.gov (United States)

Herrera, María; Tattini, Virgilio; Pitombo, Ronaldo N M; Gutiérrez, José María; Borgognoni, Camila; Vega-Baudrit, José; Solera, Federico; Cerdas, Maykel; Segura, Alvaro; Villalta, Mauren; Vargas, Mariángela; León, Guillermo

2014-11-01

Freeze-drying is used to improve the long term stability of pharmaceutical proteins. Sugars and polyols have been successfully used in the stabilization of proteins. However, their use in the development of freeze-dried antivenoms has not been documented. In this work, whole IgG snake antivenom, purified from equine plasma, was formulated with different concentrations of sorbitol, sucrose or mannitol. The glass transition temperatures of frozen formulations, determined by Differential Scanning Calorimetry (DSC), ranged between -13.5 °C and -41 °C. In order to evaluate the effectiveness of the different stabilizers, the freeze-dried samples were subjected to an accelerated stability test at 40 ± 2 °C and 75 ± 5% relative humidity. After six months of storage at 40 °C, all the formulations presented the same residual humidity, but significant differences were observed in turbidity, reconstitution time and electrophoretic pattern. Moreover, all formulations, except antivenoms freeze-dried with mannitol, exhibited the same potency for the neutralization of lethal effect of Bothrops asper venom. The 5% (w:v) sucrose formulation exhibited the best stability among the samples tested, while mannitol and sorbitol formulations turned brown. These results suggest that sucrose is a better stabilizer than mannitol and sorbitol in the formulation of freeze-dried antivenoms under the studied conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu

Directory of Open Access Journals (Sweden)

Patience Chisa Obinna-Echem

2014-10-01

Full Text Available This study investigated the ability of Lactobacillus plantarum strains (NGL5 and NGL7 and Candida tropicalis (NGY1 previously identified from akamu-a Nigerian fermented maize food with probiotic L. plantarum LpTx and Saccharomyces boulardii SB20 to ferment ground maize slurries based on pH, acidity, microbial biomass, levels of sugars and organic acids, and their antimicrobial activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli NCTC 11560, Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 using an agar spot assay. L. plantarum strains either as single or mixed starter cultures with the yeasts had growth rates ≥0.15 h-1,with pH significantly (p≤0.05 decreased to ≤3.93 after 12 h and then to ≤3.52 after 72 h and lactic acid >84 mmol L-1. The yeasts had growth rates ≥0.18 h-1 but pH was ≥4.57 with lactic acid levels ≤20.23 mmol L-1 after 72 h in the single culture fermentation. There was no inhibition in modified MRS agar: 0.2% glucose and 0.2% glucose without Tween 80. Inhibition halos in MRS agar varied from 10.6 to 23.9 mm. S. bourladii was more inhibitory towards L. monocytogenes (8.6 mm and B. cereus (5.4 mm than was C. tropicalis (1.1 and 3.3 mm for L. monocytogenes NCTC 7973 and B. cereus NCIMB 11925 respectively (0.9 mm in malt extract agar. This study showed that C. tropicalis was less inhibitory to the pathogens while antimicrobial activities of the L. plantarum strains were mainly due to acidity and the L. plantarum strains either as single or mixed cultures with the yeasts demonstrated strong fermentation ability, with significant decrease in pH which is vital in the choice of starter for product safety.

Carbon-coated ceramic membrane reactor for production of hydrogen via aqueous phase reforming of sorbitol

NARCIS (Netherlands)

Neira d'Angelo, M.F.; Ordomskiy, V.; Schouten, J.C.; Schaaf, van der J.; Nijhuis, T.A.

2014-01-01

Hydrogen was produced by aqueous-phase reforming (APR) of sorbitol in a carbon-on-alumina tubular membrane reactor (4 nm pore size, 7 cm long, 3 mm internal diameter) that allows the hydrogen gas to permeate to the shell side, whereas the liquid remains in the tube side. The hydrophobic nature of

Acute toxicity and genotoxicity study of fermented traditional herb formula Guibi-tang.

Science.gov (United States)

Park, Hwayong; Hwang, Youn-Hwan; Yang, Hye Jin; Kim, Hyun-Kyu; Song, Kyung Seuk; Ma, Jin Yeul

2014-10-28

Guibi-tang (Guipi-tang in Chinese and Kihi-to in Japanese) is a multi-herb traditional medicine commonly prescribed to treat psychoneurosis in East Asia. Although this medicine has been widely used, there is little available information on the safety and toxicity of Guibi-tang, especially on the fermented one. Guibi-tang, composed of 12 herbs, was fermented with bacteria and lyophilized. Single dose acute toxicity in rats was observed for 14 days after administration. Genetic toxicity of fermented Guibi-tang was evaluated on bacterial reverse mutation in Salmonella and Escherichia spp., chromosome aberrations in Chinese hamster ovary cells, and micronucleus formation in mice. Ingredients in FGBT were identified and quantified by high performance liquid chromatography-mass spectrometry. In acute oral toxicity study, behavior, clinical signs and body weight changes were normal observing in all experimental animals. No revertant colonies were found in any bacterial cultures examined. Morphological or numerical anomalies and significant increased number of aberrant metaphases were not observed. Micronucleus assay showed no significant increases in the frequency of inducing micronuclei in any dose examined. Decursinol, decursin, glycyrrhizin, and 6-gingerol in fermented Guibi-tang were identified and quantitated. As a whole, no acute and genotoxic effects were found in all the assays and parameters analyzed. Fermented Guibi-tang was recognized as safe and non-toxic, and therefore can be used for applications of traditional medicine in modern complementary and alternative therapeutics and health care. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentration by electromagnetic sensing.

Science.gov (United States)

Harnsoongnoen, Supakorn; Wanthong, Anuwat

2017-10-01

Magnetic sensing at microwave frequencies for real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentrations is reported. The sensing element was designed based on a coplanar waveguide (CPW) loaded with a split ring resonator (SRR), which was fabricated on a DiClad 880 substrate with a thickness of 1.6mm and relative permittivity (ε r ) of 2.2. The magnetic sensor was connected to a Vector Network Analyzer (VNA) and the electromagnetic interaction between the samples and sensor was analyzed. The magnitude of the transmission coefficient (S 21 ) was used as an indicator to detect the solution sample concentrations ranging from 0.04 to 0.20g/ml. The experimental results confirmed that the developed system using microwaves for the real-time monitoring of sucrose, sorbitol, d-glucose and d-fructose concentrations gave unique results for each solution type and concentration. Moreover, the proposed sensor has a wide dynamic range, high linearity, fast operation and low-cost. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly efficient red fluorescent organic light-emitting diodes by sorbitol-doped PEDOT:PSS

Science.gov (United States)

Zheng, Yan-Qiong; Yu, Jun-Le; Wang, Chao; Yang, Fang; Wei, Bin; Zhang, Jian-Hua; Zeng, Cheng-Hui; Yang, Yang

2018-06-01

This work shows a promising approach to improve device performance by optimizing the electron transport and hole injection layers for tetraphenyldibenzoperiflanthene (DBP):rubrene-based red fluorescent organic light-emitting diodes (OLEDs). We compared the effect of two electron transport layers (ETLs), and found that the rubrene/bathophenanthroline (Bphen) ETL-based OLED showed a much higher external quantum efficiency (EQE) (4.67%) than the Alq3 ETL-based OLED (EQE of 3.08%). The doping ratio of DBP in rubrene was tuned from 1.0 wt% to 4.5 wt%, and the 1.5 wt%-DBP:rubrene-based OLED demonstrated the highest EQE of 5.24% and lowest turn-on voltage of 2.2 V. Atomic force microscopy images indicated that 1.5 wt% DBP-doped rubrene film exhibited a regular strip shape, and this regular surface was favorable to the hole and electron recombination in the emitting layer. Finally, the sorbitol-doped poly(3, 4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was used to further improve the EQE; doping with 6 wt% sorbitol achieved the highest current efficiency of 7.03 cd A‑1 and an EQE of 7.50%. The significantly enhanced performance implies that the hole injection is a limiting factor for DBP:rubrene-based red fluorescent OLEDs.

Ethanol production from lignocellulosic materials. Fermentation and on-line analysis

Energy Technology Data Exchange (ETDEWEB)

Olsson, L.

1994-04-01

The fermentation performance of bacteria, yeast and fungi was investigated in lignocellulosic hydrolysates with the aim of finding microorganisms which both withstand the inhibitors and that have the ability to ferment pentoses. Firstly, the performance of Saccharomyces cidri, Saccharomyces cerevisiae, Lactobacillus brevis, Lactococcus lactis ssp lactis, Escherichia coli and Zymomonas mobilis was investigated in spent sulphite liquor and enzymatic hydrolysate of steam-pretreated willow. Secondly, the performance of natural and recombinant E. coli, Pichia stipitis, recombinant S. cerevisiae, S. cerevisiae in combination with xylose isomerase and Fusarium oxysporum was investigated in a xylose-rich acid hydrolysate of corn cob. Recombinant E. coli was the best alternative for fermentation of lignocellulosic hydrolysates, giving both high yields and productivities. The main drawback was that detoxification was necessary. The kinetics of the fermentation with recombinant E. coli KO11 was investigated in the condensate of steam-pretreated willow. A cost analysis of the ethanol production from willow was made, which predicted an ethanol production cost of 3.9 SEK/l for the pentose fermentation. The detoxification cost constituted 22% of this cost. The monitoring of three monosaccharides and ethanol in lignocellulosic hydro lysates is described. The monosaccharides were determined using immobilized pyranose oxidase in an on-line amperometric analyser. Immobilization and characterization of pyranose oxidase from Phanerochaete chrysosporium is also described. The ethanol was monitored on-line using a micro dialysis probe as an in situ sampling device. The dialysate components were then separated in a column liquid chromatographic system and the ethanol was selectively detected by an amperometric alcohol bio sensor. The determinations with on-line analysis methods agreed well with off-line methods. 248 refs, 4 figs, 12 tabs

Overliming detoxification of pyrolytic sugar syrup for direct fermentation of levoglucosan to ethanol.

Science.gov (United States)

Chi, Zhanyou; Rover, Marjorie; Jun, Erin; Deaton, Mark; Johnston, Patrick; Brown, Robert C; Wen, Zhiyou; Jarboe, Laura R

2013-12-01

The application of pyrolytic sugars for biofuel production through fermentation is challenged by inhibitory contaminant compounds. Inhibition is so severe that only 0.25% sugar syrup can be used. In this study, overliming was tested as a simple detoxification method, using the Escherichia coli KO11+ lgk to directly convert levoglucosan into ethanol. After treatment with at least 14.8 g/L of Ca(OH)2, fermentation with 2% (w/v) pyrolytic sugar syrup was observed with no inhibition of ethanol production. Further investigation of treatment time and temperature showed that 8-16 h of treatment at 20°C, and 1-4 h of treatment at 60°C are necessary to obtain consistent ethanol production. The samples treated with 18.5 g/L Ca(OH)2 at 60°C for 4 h showed no inhibition at 2.5%. Multiple contaminants removed by the overliming treatment were identified. This study demonstrates that overliming is a promising method for detoxification of pyrolytic sugars for fermentation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optimization of sodium hydroxide pretreatment and enzyme loading for efficient hydrolysis of rice straw to improve succinate production by metabolically engineered Escherichia coli KJ122 under simultaneous saccharification and fermentation.

Science.gov (United States)

Sawisit, Apichai; Jampatesh, Surawee; Jantama, Sirima Suvarnakuta; Jantama, Kaemwich

2018-07-01

Rice straw was pretreated with sodium hydroxide (NaOH) before subsequent use for succinate production by Escherichia coli KJ122 under simultaneous saccharification and fermentation (SSF). The NaOH pretreated rice straw was significantly enhanced lignin removal up to 95%. With the optimized enzyme loading of 4% cellulase complex + 0.5% xylanase (endo-glucanase 67 CMC-U/g, β-glucosidase 26 pNG-U/g and xylanase 18 CMC-U/g dry biomass), total sugar conversion reached 91.7 ± 0.8% (w/w). The physicochemical analysis of NaOH pretreated rice straw indicated dramatical changes in its structure, thereby favoring enzymatic saccharification. In batch SSF, succinate production of 69.8 ± 0.3 g/L with yield and productivity of 0.84 g/g pretreated rice straw and 0.76 ± 0.02 g/L/h, respectively, was obtained. Fed-batch SSF significantly improved succinate concentration and productivity to 103.1 ± 0.4 g/L and 1.37 ± 0.07 g/L/h with a comparable yield. The results demonstrated a feasibility of sequential saccharification and fermentation of rice straw as a promising process for succinate production in industrial scale. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fractal aspects of the flow and shear behaviour of free-flowable particle size fractions of pharmaceutical directly compressible excipient sorbitol.

Science.gov (United States)

Hurychová, Hana; Lebedová, Václava; Šklubalová, Zdenka; Dzámová, Pavlína; Svěrák, Tomáš; Stoniš, Jan

Flowability of powder excipients is directly influenced by their size and shape although the granulometric influence of the flow and shear behaviour of particulate matter is not studied frequently. In this work, the influence of particle size on the mass flow rate through the orifice of a conical hopper, and the cohesion and flow function was studied for four free-flowable size fractions of sorbitol for direct compression in the range of 0.080-0.400 mm. The particles were granulometricaly characterized using an optical microscopy; a boundary fractal dimension of 1.066 was estimated for regular sorbitol particles. In the particle size range studied, a non-linear relationship between the mean particle size and the mass flow rate Q10 (g/s) was detected having amaximum at the 0.245mm fraction. The best flow properties of this fraction were verified with aJenike shear tester due to the highest value of flow function and the lowest value of the cohesion. The results of this work show the importance of the right choice of the excipient particle size to achieve the best flow behaviour of particulate material.Key words: flowability size fraction sorbitol for direct compaction Jenike shear tester fractal dimension.

Yeast Derived LysA2 Can Control Bacterial Contamination in Ethanol Fermentation

Directory of Open Access Journals (Sweden)

Jun-Seob Kim

2018-05-01

Full Text Available Contamination of fuel-ethanol fermentations continues to be a significant problem for the corn and sugarcane-based ethanol industries. In particular, members of the Lactobacillaceae family are the primary bacteria of concern. Currently, antibiotics and acid washing are two major means of controlling contaminants. However, antibiotic use could lead to increased antibiotic resistance, and the acid wash step stresses the fermenting yeast and has limited effectiveness. Bacteriophage endolysins such as LysA2 are lytic enzymes with the potential to contribute as antimicrobials to the fuel ethanol industries. Our goal was to evaluate the potential of yeast-derived LysA2 as a means of controlling Lactobacillaceae contamination. LysA2 intracellularly produced by Pichia pastoris showed activity comparable to Escherichia coli produced LysA2. Lactic Acid Bacteria (LAB with the A4α peptidoglycan chemotype (L-Lys-D-Asp crosslinkage were the most sensitive to LysA2, though a few from that chemotype were insensitive. Pichia-expressed LysA2, both secreted and intracellularly produced, successfully improved ethanol productivity and yields in glucose (YPD60 and sucrose-based (sugarcane juice ethanol fermentations in the presence of a LysA2 susceptible LAB contaminant. LysA2 secreting Sacharomyces cerevisiae did not notably improve production in sugarcane juice, but it did control bacterial contamination during fermentation in YPD60. Secretion of LysA2 by the fermenting yeast, or adding it in purified form, are promising alternative tools to control LAB contamination during ethanol fermentation. Endolysins with much broader lytic spectrums than LysA2 could supplement or replace the currently used antibiotics or the acidic wash.

Multiplexed Single Intact Cell Droplet Digital PCR (MuSIC ddPCR) Method for Specific Detection of Enterohemorrhagic E. coli (EHEC) in Food Enrichment Cultures

OpenAIRE

McMahon, Tanis C.; Blais, Burton W.; Wong, Alex; Carrillo, Catherine D.

2017-01-01

Foodborne illness attributed to enterohemorrhagic E. coli (EHEC), a highly pathogenic subset of Shiga toxin-producing E. coli (STEC), is increasingly recognized as a significant public health issue. Current microbiological methods for identification of EHEC in foods often use PCR-based approaches to screen enrichment broth cultures for characteristic gene markers [i.e., Shiga toxin (stx) and intimin (eae)]. However, false positives arise when complex food matrices, such as beef, contain mixtu...

Sub-Lethal Dose of Shiga toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture.

Directory of Open Access Journals (Sweden)

Luciana eD’Alessio

2016-02-01

Full Text Available Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test, and ultrastructural analysis (transmission electron microscope. Intravenous administration of vehicle (control group, sub-lethal dose of 0.5 ηg and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n=6. Blood–Brain Barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

Bioconversion of glycerol for bioethanol production using isolated Escherichia coli SS1

Directory of Open Access Journals (Sweden)

Sheril Norliana Suhaimi

2012-06-01

Full Text Available Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production.

Isolation of Lactic Acid Bacteria with High Biological Activity from Local Fermented Dairy Products

Directory of Open Access Journals (Sweden)

B. Munkhtsetseg

2009-12-01

Full Text Available The thirty-two strains of lactic acid bacteria were isolated from the Mongolian traditional fermented dairy products, among them 25 strains show antimicrobial activity against test microorganisms including Escherichia coli , Staphylococcus aureus , Enterococcus faecalis , Pseudom о nas aeruginosa . Protease sensitivity assay demonstrated that the antimicrobial substances produced by isolates А 23, Т 2 are bacteriocins as their antibacterial activities were eliminated completely after treatment with protease. Identi fi cation of bacteria is being carried out. Among the isolates 22 strains show protease enzyme producing activity. The selected strains isolated from mare’s fermented milk (airag or kumis and yoghurt (tarag show the speci fi c protease activity from 7.9 μ g/ml to 11.9 μ g/ml. The strain T2, isolated from yoghurt exhibited the highest proteolytic activity.

Enhanced production of GDP-L-fucose by overexpression of NADPH regenerator in recombinant Escherichia coli.

Science.gov (United States)

Lee, Won-Heong; Chin, Young-Wook; Han, Nam Soo; Kim, Myoung-Dong; Seo, Jin-Ho

2011-08-01

Biosynthesis of guanosine 5'-diphosphate-L-fucose (GDP-L-fucose) requires NADPH as a reducing cofactor. In this study, endogenous NADPH regenerating enzymes such as glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (Icd), and NADP(+)-dependent malate dehydrogenase (MaeB) were overexpressed to increase GDP-L-fucose production in recombinant Escherichia coli. The effects of overexpression of each NADPH regenerating enzyme on GDP-L-fucose production were investigated in a series of batch and fed-batch fermentations. Batch fermentations showed that overexpression of G6PDH was the most effective for GDP-L-fucose production. However, GDP-L-fucose production was not enhanced by overexpression of G6PDH in the glucose-limited fed-batch fermentation. Hence, a glucose feeding strategy was optimized to enhance GDP-L-fucose production. Fed-batch fermentation with a pH-stat feeding mode for sufficient supply of glucose significantly enhanced GDP-L-fucose production compared with glucose-limited fed-batch fermentation. A maximum GDP-L-fucose concentration of 235.2 ± 3.3 mg l(-1), corresponding to a 21% enhancement in the GDP-L-fucose production compared with the control strain overexpressing GDP-L-fucose biosynthetic enzymes only, was achieved in the pH-stat fed-batch fermentation of the recombinant E. coli overexpressing G6PDH. It was concluded that sufficient glucose supply and efficient NADPH regeneration are crucial for NADPH-dependent GDP-L-fucose production in recombinant E. coli.

Fermented soybean meal improves the growth performance, nutrient digestibility, and microbial flora in piglets

Directory of Open Access Journals (Sweden)

Lin Yuan

2017-03-01

Full Text Available In order to increase nutritive values of soybean meal (SBM, 3 species of microbes were used to ferment SBM. Through a 3 × 3 orthogonal design and parameter measurements of soybean peptide and anti-nutritional factor contents in the fermented soybean meal (FSBM, it was estimated that the best microbial proportion of Bacillus subtilis, Hansenula anomala and Lactobacillus casei was 2:1:2 for SBM fermentation (P  0.05. However, newly-weaned piglets (d 28–38 fed 10% FSBM and different levels of plasma protein obtained higher average daily gain (ADG and feed conversion ratio (FCR, compared with those without FSBM but with 6% plasma protein (P < 0.05. Piglets (d 38–68 fed diets supplemented with FSBM and soybean protein concentrate (SBPC at 3.75% and 7.5% respectively increased nutrient digestibility, fecal enzyme activity and lactic acid bacteria counts, and decreased fecal Escherichia coli counts (P < 0.05, compared with the control. These data indicated that FSBM had positive effects on nutrient digestibility and fecal microflora for piglets.

Systematic Engineering of Escherichia coli for d-Lactate Production from Crude Glycerol.

Science.gov (United States)

Wang, Zei Wen; Saini, Mukesh; Lin, Li-Jen; Chiang, Chung-Jen; Chao, Yun-Peng

2015-11-04

Crude glycerol resulting from biodiesel production is an abundant and renewable resource. However, the impurities in crude glycerol usually make microbial fermentation problematic. This issue was addressed by systematic engineering of Escherichia coli for the production of d-lactate from crude glycerol. First, mgsA and the synthetic pathways of undesired products were eliminated in E. coli, rendering the strain capable of homofermentative production of optically pure d-lactate. To direct carbon flux toward d-lactate, the resulting strain was endowed with an enhanced expression of glpD-glpK in the glycerol catabolism and of a heterologous gene encoding d-lactate dehydrogenase. Moreover, the strain was evolved to improve its utilization of cruder glycerol and subsequently equipped with the FocA channel to export intracellular d-lactate. Finally, the fed-batch fermentation with two-phase culturing was carried out with a bioreactor. As a result, the engineered strain enabled production of 105 g/L d-lactate (99.9% optical purity) from 121 g/L crude glycerol at 40 h. The result indicates the feasibility of our approach to engineering E. coli for the crude glycerol-based fermentation.

Effect of sorbitol, single, and multidose activated charcoal administration on carprofen absorption following experimental overdose in dogs.

Science.gov (United States)

Koenigshof, Amy M; Beal, Matthew W; Poppenga, Robert H; Jutkowitz, L Ari

2015-01-01

To compare the effectiveness of single dose activated charcoal, single dose activated charcoal with sorbitol, and multidose activated charcoal in reducing plasma carprofen concentrations following experimental overdose in dogs. Randomized, four period cross-over study. University research setting. Eight healthy Beagles. A 120 mg/kg of carprofen was administered orally to each dog followed by either (i) a single 2 g/kg activated charcoal administration 1 hour following carprofen ingestion (AC); (ii) 2 g/kg activated charcoal with 3.84 g/kg sorbitol 1 hour following carprofen ingestion (ACS); (iii) 2 g/kg activated charcoal 1 hour after carprofen ingestion and repeated every 6 hours for a total of 4 doses (MD); (iv) no treatment (control). Plasma carprofen concentrations were obtained over a 36-hour period following carprofen ingestion for each protocol. Pharmacokinetic modeling was performed and time versus concentration, area under the curve, maximum plasma concentration, time to maximum concentration, and elimination half-life were calculated and compared among the groups using ANOVA followed by Tukey's multiple comparisons test. Activated charcoal, activated charcoal with sorbitol (ACS), and multiple-dose activated charcoal (MD) significantly reduced the area under the curve compared to the control group. AC and MD significantly reduced the maximum concentration when compared to the control group. MD significantly reduced elimination half-life when compared to ACS and the control group. There were no other significant differences among the treatment groups. Activated charcoal and ACS are as effective as MD in reducing serum carprofen concentrations following experimental overdose in dogs. Prospective studies are warranted to evaluate the effectiveness of AC, ACS, and MD in the clinical setting. © Veterinary Emergency and Critical Care Society 2015.

JNK signaling pathway regulates sorbitol-induced Tau proteolysis and apoptosis in SH-SY5Y cells by targeting caspase-3.

Science.gov (United States)

Olivera Santa-Catalina, Marta; Caballero Bermejo, Montaña; Argent, Ricardo; Alonso, Juan C; Centeno, Francisco; Lorenzo, María J

2017-12-15

Growing evidence suggests that Diabetes Mellitus increases the risk of developing Alzheimer's disease. It is well known that hyperglycemia, a key feature of Diabetes Mellitus, may induce plasma osmolarity disturbances. Both hyperglycemia and hyperosmolarity promote the altered post-translational regulation of microtubule-associated protein Tau. Interestingly, abnormal hyperphosphorylation and cleavage of Tau have been proven to lead to the genesis of filamentous structures referred to as neurofibrillary tangles, the main pathological hallmark of Alzheimer's disease. We have previously described that hyperosmotic stress induced by sorbitol promotes Tau proteolysis and apoptosis in SH-SY5Y cells via caspase-3 activation. In order to gain insights into the regulatory mechanisms of such processes, in this work we explored the intracellular signaling pathways that regulate these events. We found that sorbitol treatment significantly enhanced the activation of conventional families of MAPK in SH-SY5Y cells. Tau proteolysis was completely prevented by JNK inhibition but not affected by either ERK1/2 or p38 MAPK blockade. Moreover, inhibition of JNK, but not ERK1/2 or p38 MAPK, efficiently prevented sorbitol-induced apoptosis and caspase-3 activation. In summary, we provide evidence that JNK signaling pathway is an upstream regulator of hyperosmotic stress-induced Tau cleavage and apoptosis in SH-SY5Y through the control of caspase-3 activation. Copyright © 2017 Elsevier Inc. All rights reserved.

Aging of the Johari-Goldstein relaxation in the glass-forming liquids sorbitol and xylitol

Science.gov (United States)

Yardimci, Hasan; Leheny, Robert L.

2006-06-01

Employing frequency-dependent dielectric susceptibility we characterize the aging in two supercooled liquids, sorbitol and xylitol, below their calorimetric glass transition temperatures. In addition to the alpha relaxation that tracks the structural dynamics, the susceptibility of both liquids possesses a secondary Johari-Goldstein relaxation at higher frequencies. Following a quench through the glass transition, the susceptibility slowly approaches the equilibrium behavior. For both liquids, the magnitude of the Johari-Goldstein relaxation displays a dependence on the time since the quench, or aging time, that is quantitatively very similar to the age dependence of the alpha peak frequency. The Johari-Goldstein relaxation time remains constant during aging for sorbitol while it decreases slightly with age for xylitol. Hence, one cannot sensibly assign a fictive temperature to the Johari-Goldstein relaxation. This behavior contrasts with that of liquids lacking distinct Johari-Goldstein peaks for which the excess wing of the alpha peak tracks the main part of the peak during aging, enabling the assignment of a single fictive temperature to the entire spectrum. The aging behavior of the Johari-Goldstein relaxation time further calls into question the possibility that the relaxation time possesses stronger temperature dependence in equilibrium than is observed in the out-of-equilibrium state below the glass transition.

Structural and functional characterization of cleavage and inactivation of human serine protease inhibitors by the bacterial SPATE protease EspPα from enterohemorrhagic E. coli.

Directory of Open Access Journals (Sweden)

André Weiss

Full Text Available EspPα and EspI are serine protease autotransporters found in enterohemorrhagic Escherichia coli. They both belong to the SPATE autotransporter family and are believed to contribute to pathogenicity via proteolytic cleavage and inactivation of different key host proteins during infection. Here, we describe the specific cleavage and functional inactivation of serine protease inhibitors (serpins by EspPα and compare this activity with the related SPATE EspI. Serpins are structurally related proteins that regulate vital protease cascades, such as blood coagulation and inflammatory host response. For the rapid determination of serpin cleavage sites, we applied direct MALDI-TOF-MS or ESI-FTMS analysis of coincubations of serpins and SPATE proteases and confirmed observed cleavage positions using in-gel-digest of SDS-PAGE-separated degradation products. Activities of both serpin and SPATE protease were assessed in a newly developed photometrical assay using chromogenic peptide substrates. EspPα cleaved the serpins α1-protease inhibitor (α1-PI, α1-antichymotrypsin, angiotensinogen, and α2-antiplasmin. Serpin cleavage led to loss of inhibitory function as demonstrated for α1-PI while EspPα activity was not affected. Notably, EspPα showed pronounced specificity and cleaved procoagulatory serpins such as α2-antiplasmin while the anticoagulatory antithrombin III was not affected. Together with recently published research, this underlines the interference of EspPα with hemostasis or inflammatory responses during infection, while the observed interaction of EspI with serpins is likely to be not physiologically relevant. EspPα-mediated serpin cleavage occurred always in flexible loops, indicating that this structural motif might be required for substrate recognition.

Determination of structural and mechanical properties, diffractometry, and thermal analysis of chitosan and hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol

Directory of Open Access Journals (Sweden)

Jefferson Rotta

2011-06-01

Full Text Available In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v in water and chitosan (2% w/v in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100 of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM, differential scanning calorimetry (DSC, and thermal gravimetric analysis (TGA. The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups.

Determining the probiotic potential of cholesterol-reducing Lactobacillus and Weissella strains isolated from gherkins (fermented cucumber) and south Indian fermented koozh.

Science.gov (United States)

Anandharaj, Marimuthu; Sivasankari, Balayogan; Santhanakaruppu, Rajendran; Manimaran, Muthusamy; Rani, Rizwana Parveen; Sivakumar, Subramaniyan

2015-06-01

This study sought to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from traditionally fermented south Indian koozh and gherkin (cucumber). A total of 51 LAB strains were isolated, among which four were identified as Lactobacillus spp. and three as Weissella spp. The strains were screened for their probiotic potential. All isolated Lactobacillus and Weissella strains were capable of surviving under low pH and bile salt conditions. GI9 and FKI21 were able to survive at pH 2.0 and 0.50% bile salt for 3 h without losing their viability. All LAB strains exhibited inhibitory activity against tested pathogens and were able to deconjugate bile salt. Higher deconjugation was observed in the presence of sodium glycocholate (P Strain FKI21 showed maximum auto-aggregation (79%) and co-aggregation with Escherichia coli MTCC 1089 (68%). Exopolysaccharide production of LAB strains ranged from 68.39 to 127.12 mg/L (P Lactobacillus crispatus and Weissella koreensis, respectively. This is the first study to report isolation of W. koreensis FKI21 from fermented koozh and demonstrates its cholesterol-reducing potential. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Microbiological Safety Assessment of Fermented Cassava Flour “Lafun” Available in Ogun and Oyo States of Nigeria

Directory of Open Access Journals (Sweden)

A. O. Adebayo-Oyetoro

2013-01-01

Full Text Available The microorganisms involved in the fermentation and spoilage of fermented cassava flour were investigated. The water samples used at the different processing sites were also investigated to determine their safety status. There was predominance of Staphylococcus aureus, Aspergillus spp., and Escherichia coli in all samples. Coliforms were observed to be present in all of the processing water. In the fermented cassava flour, the total bacterial count ranged between 4.9×106 cfu/mL from Eleso, Bakatari, and Oja Odan processing sites and 8.10×106 cfu/mL in Eruku processing site. The majority of the microorganisms involved in the spoilage of “lafun” were found to be Aspergillus niger which ranged between 4.6×105 cfu/mL in Eleso and 8.1×105 cfu/mL in Kila. The control sample prepared in the laboratory had a low microbial load compared to samples collected from various sites and markets.

Gastrointestinal ecosystem and immunological responses in E.coli challenged pigs after weaning fed liquid diets containing whey permeate fermented with different lactic acid bacteria

DEFF Research Database (Denmark)

Sugiharto, Sugiharto; Lauridsen, Charlotte; Jensen, Bent Borg

2015-01-01

The objective of this study was to investigate the effect of feeding liquid feed containing whey permeate (WP) fermented with different lactic acid bacteria (LAB) on the microbiota and mucosal immune responses of Escherichia coli F4 inoculated piglets post weaning. The study consisted of 52 weaned...... diet tended (P = 0.069) to lower total coliform and enhanced (P = 0.050) LAB:coliform ratio in GIT digesta. The faecal LAB:coliform ratio was higher (P .... Intestinal immunoglobulin (Ig) A decreased (P liquid feed containing W. viridescens-fermented WP improved the intestinal health...

Contrasting dynamics of fragile and non-fragile polyalcohols through the glass, and dynamical, transitions: A comparison of neutron scattering and dielectric relaxation data for sorbitol and glycerol.

Science.gov (United States)

Migliardo, F; Angell, C A; Magazù, S

2017-01-01

Glycerol and sorbitol are glass-forming hydrogen-bonded systems characterized by intriguing properties which make these systems very interesting also from the applications point of view. The goal of this work is to relate the hydrogen-bonded features, relaxation dynamics, glass transition properties and fragility of these systems, in particular to seek insight into their very different liquid fragilities. The comparison between glycerol and sorbitol is carried out by collecting the elastic incoherent neutron scattering (EINS) intensity as a function of temperature and of the instrumental energy resolution. Intensity data vs temperature and resolution are analyzed in terms of thermal restraint and Resolution Elastic Neutron Scattering (RENS) approaches. The number of OH groups, which are related to the connecting sites, is a significant parameter both in the glass transition and in the dynamical transition. On the other hand, the disordered nature of sorbitol is confirmed by the existence of different relaxation processes. From the applications point of view, glycerol and sorbitol have remarkable bioprotectant properties which make these systems useful in different technological and industrial fields. Furthermore, polyols are rich in glassforming liquid phenomenology and highly deserving of study in their own right. The comparison of EINS and calorimetric data on glycerol and sorbitol helps provide a connection between structural relaxation, dynamical transition, glass transition, and fragility. The evaluation of the inflection point in the elastic intensity behavior as a function of temperature and instrumental energy resolution provides a confirmation of the validity of the RENS approach. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo. Copyright © 2016. Published by Elsevier B.V.

FERMENTATION ACTIVITY OF LACTOSE-FERMENTATION YEAST IN WHEY-MALT WORT

Directory of Open Access Journals (Sweden)

E. V. Greek

2013-04-01

Full Text Available The main parameters of fermentation of whey-malt wort with the use of different strains of lactose-fermentation yeast was investigated experimentally. According to the findings of investigation of fermentive activity for different types of lactose-fermentation microorganisms in whey-malt wort it was found that the most active spirituous fermentation for all parameters was in wort fermented by microorganisms Zygosaccharomyces lactis 868-K and Saccharomyces lactis 95. High capacity for utilization of malt carbohydrates represented by easily metabolized carbohydrates of malt extract was determined. Also organoleptic analysis of fermented whey drinks derived from the renewed mixtures of dry whey and fermented malt and yeast Zygosaccharomyces lactis 868-K and Saccharomyces lactis 95 was carried out. It was found that the drink fermented with yeast Zygosaccharomyces lactis 868-K had intense refreshing flavor of rye bread with fruit tones. Intensity growth of aromatization for complex of sample with microorganisms Saccharomyces lactis 95, indicating high organoleptic indexes of the drink was observed.

Influence of solid state fermentation by Trichoderma spp. on solubility, phenolic content, antioxidant, and antimicrobial activities of commercial turmeric.

Science.gov (United States)

Mohamed, Saleh A; Saleh, Rashad M; Kabli, Saleh A; Al-Garni, Saleh M

2016-05-01

The influence of solid state fermentation (SSF) by Trichoderma spp. on the solubility, total phenolic content, antioxidant, and antibacterial activities of turmeric was determined and compared with unfermented turmeric. The solubility of turmeric was monitored by increase in its phenolic content. The total phenolic content of turmeric extracted by 80% methanol and water after SSF by six species of Trichoderma spp. increased significantly from 2.5 to 11.3-23.3 and from 0.5 to 13.5-20.4 GAE/g DW, respectively. The antioxidant activities of fermented turmeric were enhanced using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS), and ferric ion-reducing antioxidant power (FRAP) assays. The antibacterial activity of fermented turmeric against human-pathogenic bacteria Escherichia coli, Streptococcus agalactiae, Staphylococcus aureus, Entreococcus faecalis, Methicillin-Resistant S. aureus, Klebsiella pneumonia, and Pseudomonas aeruginosae showed a broad spectrum inhibitory effect. In conclusion, the results indicated the potentials of using fermented turmeric as natural antioxidant and antimicrobial material for food applications.

Hyperglycemia Promotes Schwann Cell De-differentiation and De-myelination via Sorbitol Accumulation and Igf1 Protein Down-regulation*

Science.gov (United States)

Hao, Wu; Tashiro, Syoichi; Hasegawa, Tomoka; Sato, Yuiko; Kobayashi, Tami; Tando, Toshimi; Katsuyama, Eri; Fujie, Atsuhiro; Watanabe, Ryuichi; Morita, Mayu; Miyamoto, Kana; Morioka, Hideo; Nakamura, Masaya; Matsumoto, Morio; Amizuka, Norio; Toyama, Yoshiaki; Miyamoto, Takeshi

2015-01-01

Diabetes mellitus (DM) is frequently accompanied by complications, such as peripheral nerve neuropathy. Schwann cells play a pivotal role in regulating peripheral nerve function and conduction velocity; however, changes in Schwann cell differentiation status in DM are not fully understood. Here, we report that Schwann cells de-differentiate into immature cells under hyperglycemic conditions as a result of sorbitol accumulation and decreased Igf1 expression in those cells. We found that de-differentiated Schwann cells could be re-differentiated in vitro into mature cells by treatment with an aldose reductase inhibitor, to reduce sorbitol levels, or with vitamin D3, to elevate Igf1 expression. In vivo DM models exhibited significantly reduced nerve function and conduction, Schwann cell de-differentiation, peripheral nerve de-myelination, and all conditions were significantly rescued by aldose reductase inhibitor or vitamin D3 administration. These findings reveal mechanisms underlying pathological changes in Schwann cells seen in DM and suggest ways to treat neurological conditions associated with this condition. PMID:25998127

Polar silica-based stationary phases. Part II- Neutral silica stationary phases with surface bound maltose and sorbitol for hydrophilic interaction liquid chromatography.

Science.gov (United States)

Rathnasekara, Renuka; El Rassi, Ziad

2017-07-28

Two neutral polyhydroxylated silica bonded stationary phases, namely maltose-silica (MALT-silica) and sorbitol-silica (SOR-silica), have been introduced and chromatographically characterized in hydrophilic interaction liquid chromatography (HILIC) for a wide range of polar compounds. The bonding of the maltose and sorbitol to the silica surface was brought about by first converting bare silica to an epoxy-activated silica surface via reaction with γ-glycidoxypropyltrimethoxysilane (GPTMS) followed by attaching maltose and sorbitol to the epoxy surface in the presence of the Lewis acid catalyst BF 3 .ethereate. Both silica based columns offered the expected retention characteristics usually encountered for neutral polar surface. The retention mechanism is majorly based on solute' differential partitioning between an organic rich hydro-organic mobile phase (e.g., ACN rich mobile phase) and an adsorbed water layer on the surface of the stationary phase although additional hydrogen bonding was also responsible in some cases for solute retention. The MALT-silica column proved to be more hydrophilic and offered higher retention, separation efficiency and resolution than the SOR-silica column among the tested polar solutes such as derivatized mono- and oligosaccharides, weak phenolic acids, cyclic nucleotide monophosphate and nucleotide-5'-monophosphates, and weak bases, e.g., nucleobases and nucleosides. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimization of Fermentation Conditions for the Production of Bacteriocin Fermentate

Science.gov (United States)

2015-03-30

FERMENTATION CONDITIONS FOR THE PRODUCTION OF BACTERIOCIN “ FERMENTATE ” by Anthony Sikes Wayne Muller and Claire Lee March 2015...From - To) October 2010 – November 2013 4. TITLE AND SUBTITLE OPTIMIZATION OF FERMENTATION CONDITIONS FOR THE PRODUCTION OF BACTERIOCIN “ FERMENTATE ...nisin and pediocin. Whey + yeast extract was the best performing whey fermentation media. The nisin producer strain Lactococcus. lactis ssp. lactis was

Alternate economical starchy substrates for the production of 70% sorbitol

Energy Technology Data Exchange (ETDEWEB)

Upadhyay, C.M. (Sarabhai Research Centre, Baroda (India). Industrial Enzymes Dept.); Nehete, P.N. (Sarabhai Research Centre, Baroda (India). Industrial Fermentation Div.); Shah, D.N. (GSFC Research and Development Centre, Fertilizernagar (India). Biotechnology Dept.); Shah, N.K. (Armour Chemicals Pvt. Ltd., Ankleshwar (India)); Shankar, V. (National Chemical Lab., Pune (India). Biochemistry Div.); Kothari, R.M. (Thapar Corporate Research and Development Centre, Patiala (India). Biotechnology Div.)

1991-03-01

In view of the soaring prices of corn and tapioca starch, use of their hydrolysate in the production of 70% sorbitol became less remunerative. Therefore, an economical alternative is explored by using hydrolysates of cereal flours, namely, rice (Oryzae sativa), wheat (Triticum aestivum), jowar (Sorghum vulgare) and bajra (Pennisetum typhoideum). A protocol is devised to (a) prepare their high DE hydrolysates, (b) purify it after saccharification, (c) monitor the chemical chracteristics of concentrated hydrolysate, as feedstock for Raney nickel catalyzed pressure hydrogenation and (d) finally prepare 70% sorbital. Merits and demerits of hydrolysates of these cereal flours are discussed in terms of operational limitations and percentage recovery, the governing factors for their industrial acceptability. Rice flour hydrolysate appears to be an alternative substrate, operationally and economically. (orig.).

Edible Film from Polyblend of Ginger Starch, Chitosan, and Sorbitol as Plasticizer

Science.gov (United States)

Sariningsih, N.; Putra, Y. P.; Pamungkas, W. P.; Kusumaningsih, T.

2018-03-01

Polyblend ginger starch/chitosan based edible film has been succesfully prepared and characterized. The purpose of this research was to produce edible film from polyblend of ginger starch, chitosan, and sorbitol as plasticizer. The resulted edible film were characterized by using FTIR, TGA and UTM. Edible film of ginger starch had OH vibration (3430 cm-1). Besides, edible film had elongation up to 15.63%. The thermal degradation of this material reached 208°C indicating high termal stability. The water uptake of the edible film was 42.85%. It concluded that edible film produce in this research has potential as a packaging.

Conversion of cellulose and cellobiose into sorbitol catalyzed by ruthenium supported on a polyoxometalate/metal-organic framework hybrid.

Science.gov (United States)

Chen, Jinzhu; Wang, Shengpei; Huang, Jing; Chen, Limin; Ma, Longlong; Huang, Xing

2013-08-01

Cellulose and cellobiose were selectively converted into sorbitol over water-tolerant phosphotungstic acid (PTA)/metal- organic-framework-hybrid-supported ruthenium catalysts, Ru-PTA/MIL-100(Cr), under aqueous hydrogenation conditions. The goal was to investigate the relationship between the acid/metal balance of bifunctional catalysts Ru-PTA/MIL-100(Cr) and their performance in the catalytic conversion of cellulose and cellobiose into sugar alcohols. The control of the amount and strength of acid sites in the supported PTA/MIL-100(Cr) was achieved through the effective control of encapsulated-PTA loading in MIL-100(Cr). This design and preparation method led to an appropriately balanced Ru-PTA/MIL-100(Cr) in terms of Ru dispersion and hydrogenation capacity on the one hand, and acid site density of PTA/MIL-100(Cr) (responsible for acid-catalyzed hydrolysis) on the other hand. The ratio of acid site density to the number of Ru surface atoms (nA /nRu ) of Ru-PTA/MIL-100(Cr) was used to monitor the balance between hydrogenation and hydrolysis functions; the optimum balance between the two catalytic functions, that is, 8.84sorbitol of 57.9% at complete conversion of cellulose, and 97.1% yield in hexitols with a selectivity for sorbitol of 95.1% at complete conversion of cellobiose) were obtained using a Ru-PTA/MIL-100(Cr) catalyst with loadings of 3.2 wt % for Ru and 16.7 wt % for PTA. This research thus opens new perspectives for the rational design of acid/metal bifunctional catalysts for biomass conversion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quality and microbiological safety of fermented bovine dairy produced in Federal District, Brazil

Directory of Open Access Journals (Sweden)

Diana Lima dos Reis

2014-12-01

Full Text Available Considering the growing importance of fermented dairy products in the domestic market and the scarcity of data in the Federal District (DF, it was evaluated the quality and microbiological safety of these products in the DF and its adaptation to current standards. The study was conducted in five dairy being collected 105 samples of fermented dairy products corresponding to 21 lots (n = 5 per lot, with 65 samples of yogurt, 20 of curd and 20 of fermented dairy drink. All samples were submitted to a count of aerobic mesophilic, psychrotrophic, coliforms at 35 ° C, Escherichia coli, Staphylococcus coagulase positive, Salmonella spp., molds, yeasts and viable lactic acid bacteria (BAL. The total lots analyzed, 62% were considered acceptable under the Regulatory Instructions n ° 46/2007 and n ° 16/2005. In order of quality, fermented dairy drink was the one with lots more apt to consumption (75% followed by yoghurt (61.5% and, lastly, curd (50%. For samples units, the results showed that: 17% of yoghurt samples, 15% of curd and 20% of fermented dairy drink showed scores above the allowed CT; 11% of yoghurt samples and 30% of fermented dairy drink showed BAL counts below specific minimum limits; and 61% samples of yogurt and curd were 30% of curd was with yeasts and molds counts above permitted. No samples showed the development of E. coli or Salmonella spp. Despite the absence of microbiological hazards in the samples analyzed, the study indicates problems in the production of these products in the DF that may be related to deficiencies in hygienic of the processes, most rigor in the quality controls of dairy and oversight of industries is needed.

PCR approach for rapid detection of Escherichia coli in tempe using a specific primer

Directory of Open Access Journals (Sweden)

Siti Harnina Bintari

2014-12-01

Full Text Available Tempe known as a traditional fermented food originated from Indonesia. It has a unique flavour and texture. It also contains high protein and usually serves to substitute meat, fish, or egg as a complement to rice. The manufacture process of Tempe is quite complex and mostly, the traditional process has not employed the hygienic standard. In the process of Tempe making, there are two critical stages of the whole process; i.e. soaking of soybeans and solid state fermentation by Rhizopus sp. During the process, foodborne pathogen bacteria such as Escherichia coli could contaminate the product of Tempe. The bacterial contamination could be revealed through culture dependent methods which is costly, laborious, and time consuming. Therefore, the culture-independent method such as polymerase chain reaction using a specific primer could be applied to detect target microorganism to save time and labour. In this study, thirty-one Tempe samples collected from different manufacturers in Semarang, Central Java, Indonesia were analysed by PCR. In order to obtain the bacterial genomic DNA, a modified Chelex 100-Microwave method was employed. The results of DNA extraction showed that the method was an applicable method. It gave high quantity and quality of DNA; therefore, it could be applied in the PCR reaction. The DNA samples were employed in PCR for detection of Escherichia coli using Ecoli706F/R. It was found that 27 out of 31 samples were detected having Escherichia coli contamination showed by the presence of the amplified product size 706 bp. The application of this method could significantly reduce costs and time of analysis in the laboratory. Further response after E. coli were detected could be employed, including investigation of the critical factors in Tempe manufacturing process which allowed E. coli contamination.

Electro-Fermentation - Merging Electrochemistry with Fermentation in Industrial Applications.

Science.gov (United States)

Schievano, Andrea; Pepé Sciarria, Tommy; Vanbroekhoven, Karolien; De Wever, Heleen; Puig, Sebastià; Andersen, Stephen J; Rabaey, Korneel; Pant, Deepak

2016-11-01

Electro-fermentation (EF) merges traditional industrial fermentation with electrochemistry. An imposed electrical field influences the fermentation environment and microbial metabolism in either a reductive or oxidative manner. The benefit of this approach is to produce target biochemicals with improved selectivity, increase carbon efficiency, limit the use of additives for redox balance or pH control, enhance microbial growth, or in some cases enhance product recovery. We discuss the principles of electrically driven fermentations and how EF can be used to steer both pure culture and microbiota-based fermentations. An overview is given on which advantages EF may bring to both existing and innovative industrial fermentation processes, and which doors might be opened in waste biomass utilization towards added-value biorefineries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acoustic excitations in glassy sorbitol and their relation with the fragility and the boson peak

Science.gov (United States)

Ruta, B.; Baldi, G.; Scarponi, F.; Fioretto, D.; Giordano, V. M.; Monaco, G.

2012-12-01

We report a detailed analysis of the dynamic structure factor of glassy sorbitol by using inelastic X-ray scattering and previously measured light scattering data [B. Ruta, G. Monaco, F. Scarponi, and D. Fioretto, Philos. Mag. 88, 3939 (2008), 10.1080/14786430802317586]. The thus obtained knowledge on the density-density fluctuations at both the mesoscopic and macroscopic length scale has been used to address two debated topics concerning the vibrational properties of glasses. The relation between the acoustic modes and the universal boson peak (BP) appearing in the vibrational density of states of glasses has been investigated, also in relation with some recent theoretical models. Moreover, the connection between the elastic properties of glasses and the slowing down of the structural relaxation process in supercooled liquids has been scrutinized. For what concerns the first issue, it is here shown that the wave vector dependence of the acoustic excitations can be used, in sorbitol, to quantitatively reproduce the shape of the boson peak, supporting the relation between BP and acoustic modes. For what concerns the second issue, a proper study of elasticity over a wide spatial range is shown to be fundamental in order to investigate the relation between elastic properties and the slowing down of the dynamics in the corresponding supercooled liquid phase.

A single amino acid change (Y318F) in the L-arabitol dehydrogenase (LadA) from Aspergillus niger results in a significant increase in affinity for D-sorbitol

Science.gov (United States)

2009-01-01

Background L-arabitol dehydrogenase (LAD) and xylitol dehydrogenase (XDH) are involved in the degradation of L-arabinose and D-xylose, which are among the most abundant monosaccharides on earth. Previous data demonstrated that LAD and XDH not only differ in the activity on their biological substrate, but also that only XDH has significant activity on D-sorbitol and may therefore be more closely related to D-sorbitol dehydrogenases (SDH). In this study we aimed to identify residues involved in the difference in substrate specificity. Results Phylogenetic analysis demonstrated that LAD, XDH and SDH form 3 distinct groups of the family of dehydrogenases containing an Alcohol dehydrogenase GroES-like domain (pfam08240) and likely have evolved from a common ancestor. Modelling of LadA and XdhA of the saprobic fungus Aspergillus niger on human SDH identified two residues in LadA (M70 and Y318), that may explain the absence of activity on D-sorbitol. While introduction of the mutation M70F in LadA of A. niger resulted in a nearly complete enzyme inactivation, the Y318F resulted in increased activity for L-arabitol and xylitol. Moreover, the affinity for D-sorbitol was increased in this mutant. Conclusion These data demonstrates that Y318 of LadA contributes significantly to the substrate specificity difference between LAD and XDH/SDH. PMID:19674460

Controlling alchohol fermentations

Energy Technology Data Exchange (ETDEWEB)

Leedham, P A; Tubb, R S

1983-09-21

In the initial stages of a fermentation of carbohydrate to EtOH, the growth of the yeast is controlled by monitoring the pH of a fermenting liquid or wort and controlling the supply of O/sub 2/ in accordance with the pH. The temperature of the fermenting liquid is also controlled in dependence upon the pH. The control of the fermentation process is carried out automatically by an apparatus including a fermentation vessel, a pH sensor arranged to provide an output signal representative of the pH of the liquid in the vessel, memory means to store information on the required pH with regard to the fermentation time, means to inject O/sub 2/ into the fermenting liquid and control means to compare the output signal of the pH sensor at a particular time with that of the required pH at that time, and in the event of the pH of the fermenting liquid lagging behind that required, actuate the means to inject O/sub 2/ into the fermenting liquid to increase the O/sub 2/ content of the fermenting liquid.

Enhancing GDP-fucose production in recombinant Escherichia coli by metabolic pathway engineering.

Science.gov (United States)

Zhai, Yafei; Han, Donglei; Pan, Ying; Wang, Shuaishuai; Fang, Junqiang; Wang, Peng; Liu, Xian-wei

2015-02-01

Guanosine 5'-diphosphate (GDP)-fucose is the indispensible donor substrate for fucosyltransferase-catalyzed synthesis of fucose-containing biomolecules, which have been found involving in various biological functions. In this work, the salvage pathway for GDP-fucose biosynthesis from Bacterioides fragilis was introduced into Escherichia coli. Besides, the biosynthesis of guanosine 5'-triphosphate (GTP), an essential substrate for GDP-fucose biosynthesis, was enhanced via overexpression of enzymes involved in the salvage pathway of GTP biosynthesis. The production capacities of metabolically engineered strains bearing different combinations of recombinant enzymes were compared. The shake flask fermentation of the strain expressing Fkp, Gpt, Gmk and Ndk obtained the maximum GDP-fucose content of 4.6 ± 0.22 μmol/g (dry cell mass), which is 4.2 fold that of the strain only expressing Fkp. Through fed-batch fermentation, the GDP-fucose content further rose to 6.6 ± 0.14 μmol/g (dry cell mass). In addition to a better productivity than previous fermentation processes based on the de novo pathway for GDP-fucose biosynthesis, the established schemes in this work also have the advantage to be a potential avenue to GDP-fucose analogs encompassing chemical modification on the fucose residue. Copyright © 2014 Elsevier Inc. All rights reserved.

Lignocellulosic Fermentation of Wild Grass Employing Recombinant Hydrolytic Enzymes and Fermentative Microbes with Effective Bioethanol Recovery

Directory of Open Access Journals (Sweden)

Saprativ P. Das

2013-01-01

Full Text Available Simultaneous saccharification and fermentation (SSF studies of steam exploded and alkali pretreated different leafy biomass were accomplished by recombinant Clostridium thermocellum hydrolytic enzymes and fermentative microbes for bioethanol production. The recombinant C. thermocellum GH5 cellulase and GH43 hemicellulase genes expressed in Escherichia coli cells were grown in repetitive batch mode, with the aim of enhancing the cell biomass production and enzyme activity. In batch mode, the cell biomass (A600 nm of E. coli cells and enzyme activities of GH5 cellulase and GH43 hemicellulase were 1.4 and 1.6 with 2.8 and 2.2 U·mg−1, which were augmented to 2.8 and 2.9 with 5.6 and 3.8 U·mg−1 in repetitive batch mode, respectively. Steam exploded wild grass (Achnatherum hymenoides provided the best ethanol titres as compared to other biomasses. Mixed enzyme (GH5 cellulase, GH43 hemicellulase mixed culture (Saccharomyces cerevisiae, Candida shehatae system gave 2-fold higher ethanol titre than single enzyme (GH5 cellulase single culture (Saccharomyces cerevisiae system employing 1% (w/v pretreated substrate. 5% (w/v substrate gave 11.2 g·L−1 of ethanol at shake flask level which on scaling up to 2 L bioreactor resulted in 23 g·L−1 ethanol. 91.6% (v/v ethanol was recovered by rotary evaporator with 21.2% purification efficiency.

A quantitative study of methanol/sorbitol co-feeding process of a Pichia pastoris Mut+/pAOX1-lacZ strain

Science.gov (United States)

2013-01-01

Background One of the main challenges for heterologous protein production by the methylotrophic yeast Pichia pastoris at large-scale is related to its high oxygen demand. A promising solution is a co-feeding strategy based on a methanol/sorbitol mixture during the induction phase. Nonetheless, a deep understanding of the cellular physiology and the regulation of the AOX1 promoter, used to govern heterologous protein production, during this co-feeding strategy is still scarce. Results Transient continuous cultures with a dilution rate of 0.023 h-1 at 25°C were performed to quantitatively assess the benefits of a methanol/sorbitol co-feeding process with a Mut+ strain in which the pAOX1-lacZ construct served as a reporter gene. Cell growth and metabolism, including O2 consumption together with CO2 and heat production were analyzed with regard to a linear change of methanol fraction in the mixed feeding media. In addition, the regulation of the promoter AOX1 was investigated by means of β-galactosidase measurements. Our results demonstrated that the cell-specific oxygen consumption (qO2) could be reduced by decreasing the methanol fraction in the feeding media. More interestingly, maximal β-galactosidase cell-specific activity (>7500 Miller unit) and thus, optimal pAOX1 induction, was achieved and maintained in the range of 0.45 ~ 0.75 C-mol/C-mol of methanol fraction. In addition, the qO2 was reduced by 30% at most in those conditions. Based on a simplified metabolic network, metabolic flux analysis (MFA) was performed to quantify intracellular metabolic flux distributions during the transient continuous cultures, which further shed light on the advantages of methanol/sorbitol co-feeding process. Finally, our observations were further validated in fed-batch cultures. Conclusion This study brings quantitative insight into the co-feeding process, which provides valuable data for the control of methanol/sorbitol co-feeding, aiming at enhancing biomass and

Production and purification of anti-bacterial biometabolite from wild-type Lactobacillus, isolated from fermented bamboo shoot: future suggestions and a proposed system for secondary metabolite onsite recovery during continuous fermentation.

Science.gov (United States)

Badwaik, Laxmikant S; Borah, Pallab Kumar; Deka, Sankar C

2015-02-01

Wild-type lactobacillus isolated form Khorisa, a fermented bamboo shoot product of Assam, India were evaluated for production anti-bacterial secondary biometabolites, against Staphylococcus aureus. Submerged fermentation technique was used for the production of secondary anti-microbial biometabolite by a single wild-type lactobacillus strain, which tested positive for the release of anti-bacterial factor(s). Crude cell-free supernatant was obtained, followed by extraction in water-immiscible solvents viz., chloroform, hexane, petroleum ether. Chloroform extract of cell-free crude supernatant showed maximum yield (0.054 g/ml) and inhibited all indicator bacterial strains viz., Escherichia coli, Staphylococcus aureus, and Bacillus cereus. Yields of hexane and petroleum ether extract were 0.052 and 0.026 g/ml, respectively. Minimum lethal dose concentration assay of the chloroform extract showed LDmin values at 27, 1.68, and 1.68 mg/ml for E. coli, S. aureus, and B. cereus, respectively. Kill time for all the indicator bacterial strains were less than 12 h. The efficacy of the anti-bacterial substance seemed to depend on the presence of organic acids, particularly lactic acid. Conceptual-based suggestion for the development of an onsite secondary metabolites recovery system during continuous fermentation has also been attempted.

Optimizing strategy for Escherichia coli growth and hydrogen production during glycerol fermentation in batch culture: Effects of some heavy metal ions and their mixtures

International Nuclear Information System (INIS)

Trchounian, Karen; Poladyan, Anna; Trchounian, Armen

2016-01-01

Highlights: • Effects of heavy metals on Escherichia coli were revealed during glycerol fermentation at pH 6.5. • Ni"2"+ + Fe"2"+ (0.05 mM) mixture stimulated up to 1.5-fold bacterial biomass yield. • Ni"2"+ + Fe"3"+ (0.05 mM), Ni"2"+ + Fe"3"+ + Mo"6"+ (0.02 mM) and Fe"3"+ + Mo"6"+ enhanced (up to 3-fold) H_2 production. • Discrimination between Fe"2"+ and Fe"3"+ was important for H_2 production. • Cu"+ and Cu"2"+ (0.1 mM) inhibited H_2 production. - Abstract: Hydrogen (H_2) is well-known effective, ecologically clean and renewable fuel. Bacterial H_2 production is a promising one and its use in industrial level is expected to increase in the nearest future to establish sustainable and renewable energy source. Escherichia coli wild type BW25113 growth yield was shown to be stimulated 1.3–1.5-fold by nickel (Ni"2"+), iron (Fe"2"+, Fe"3"+) ions and by some metal ion mixtures: Ni"2"+ + Fe"2"+ + molybdenum (Mo"6"+), Ni"2"+ + Fe"3"+, Ni"2"+ + Fe"2"+ and Mo"6"+ + Fe"3"+ in low concentrations (<0.05 mM) stimulated the growth during glycerol (10 g L"−"1) fermentation up to stationary phase at pH 6.5; Ni"2"+ + Fe"2"+ mixture showed the maximal effect. However, the same concentrations of these metals and their mixtures had no effects or slightly inhibited bacterial specific growth rate: it was suppressed ∼1.2-fold upon Ni"2"+, Fe"3"+, Mo"6"+ and Ni"2"+ + Mo"6"+ mixture supplementation. H_2 production by E. coli from glycerol was observed with the yield of 0.75 ± 0.02 mmol L"−"1. Moreover, H_2 yield was markedly stimulated 1.7–3-fold in the presence of Ni"2"+ + Fe"3"+, Ni"2"+ + Fe"3"+ + Mo"6"+ and Fe"3"+ + Mo"6"+ mixtures, but not sole metals: maximal stimulation was established by Fe"3"+ + Mo"6"+ mixture with the concentrations of 0.05 mM and 0.02 mM, respectively. While copper (Cu"+, Cu"2"+) ions in low concentration (0.1 mM) had H_2 production suppressing effect. The results point out that some heavy metal ions and their mixtures can stimulate E

Detección de Escherichia coli O157: H7 en carne picada fresca y hamburguesas congeladas Escherichia coli O157: H7 detection in fresh ground beef and hamburgers

Directory of Open Access Journals (Sweden)

M. A. Marzocca

2006-03-01

Full Text Available Escherichia coli O157:H7 es un patógeno emergente asociado a enfermedades transmitidas por alimentos. En el año 1982 fue reconocido por primera vez, en los Estados Unidos, como causante de dos brotes de colitis hemorrágica. Hoy se sabe que la mayoría de los casos de síndrome urémico hemolítico son ocasionados por este microorganismo. El objetivo del trabajo fue detectar su presencia en carne picada fresca y hamburguesas congeladas, muestras obtenidas en puntos de venta de nuestra cadena de supermercados en un total de 37 y 43, respectivamente, en el período comprendido entre abril de 2003 y agosto de 2004. Las mismas fueron procesadas utilizando el caldo selectivo para enriquecimiento EC modificado conteniendo novobiocina, seguido de la aplicación de un método de inmunocaptura (TECRA E. COLI O157 IMMUNOCAPTURE TM ECOICM 20, y posterior aislamiento en agar MacConkey sorbitol suplementado con cefixima y telurito de potasio y un medio cromogénico. Las cepas sospechosas fueron caracterizadas a genotípicamente mediante la detección de los genes de virulencia stx1, stx2, eaeA y EHEC-hlyA por PCR e hibridación con sondas genéticas, b fenotípicamente mediante la determinación del serotipo, sensibilidad a los antimicrobianos por el método de difusión de Kirby-Bauer y producción de Stx por ensayo de citotoxicidad específica en células Vero. Se aisló E. coli O157:H7 en una sola muestra de carne picada fresca (2,7% caracterizada como gen eae (+/stx2/EHEC-hlyA.Escherichia coli O157:H7 is an emergent pathogen associated with food transmitted diseases. In 1982, Escherichia coli 0157:H7 was for the first time identified as the cause of two hemorrhagic colitis outbreaks in the United States. It is now well known that most cases of hemolytic uremic syndrome are caused by these bacteria. The objective of this work was to detect the microorganism in fresh ground beef and hamburgers. From April 2003 to August 2004 samples were taken at sale

Hyperglycemia Promotes Schwann Cell De-differentiation and De-myelination via Sorbitol Accumulation and Igf1 Protein Down-regulation.

Science.gov (United States)

Hao, Wu; Tashiro, Syoichi; Hasegawa, Tomoka; Sato, Yuiko; Kobayashi, Tami; Tando, Toshimi; Katsuyama, Eri; Fujie, Atsuhiro; Watanabe, Ryuichi; Morita, Mayu; Miyamoto, Kana; Morioka, Hideo; Nakamura, Masaya; Matsumoto, Morio; Amizuka, Norio; Toyama, Yoshiaki; Miyamoto, Takeshi

2015-07-10

Diabetes mellitus (DM) is frequently accompanied by complications, such as peripheral nerve neuropathy. Schwann cells play a pivotal role in regulating peripheral nerve function and conduction velocity; however, changes in Schwann cell differentiation status in DM are not fully understood. Here, we report that Schwann cells de-differentiate into immature cells under hyperglycemic conditions as a result of sorbitol accumulation and decreased Igf1 expression in those cells. We found that de-differentiated Schwann cells could be re-differentiated in vitro into mature cells by treatment with an aldose reductase inhibitor, to reduce sorbitol levels, or with vitamin D3, to elevate Igf1 expression. In vivo DM models exhibited significantly reduced nerve function and conduction, Schwann cell de-differentiation, peripheral nerve de-myelination, and all conditions were significantly rescued by aldose reductase inhibitor or vitamin D3 administration. These findings reveal mechanisms underlying pathological changes in Schwann cells seen in DM and suggest ways to treat neurological conditions associated with this condition. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Characterization of fermented black soybean natto inoculated with Bacillus natto during fermentation.

Science.gov (United States)

Hu, Yongjin; Ge, Changrong; Yuan, Wei; Zhu, Renjun; Zhang, Wujiu; Du, Lijuan; Xue, Jie

2010-05-01

To make nutrients more accessible and further increase biological activity, cooked black soybeans were inoculated with Bacillus natto and fermented at 37 degrees C for 48 h. The changes in physiochemical properties of fermented black soybean natto were investigated. The inoculation procedure significantly increased moisture, viscosity, color, polyphenol compounds and anthocyanin, and significantly decreased hardness after 48 h fermentation. Fibrinolytic and caseinolytic protease, beta-glucosidase activities, TCA-soluble nitrogen, and ammonia nitrogen contents in the inoculated samples significantly increased as fermentation time increased. Genistin and daidzin concentrations gradually decreased with increased fermentation time. However, genistein and daidzein increased with fermentation time, which reached 316.8 and 305.2 microg g(-1) during 48 h fermentation, respectively. DPPH radical scavenging activities of the fermented black soybeans increased linearly with fermentation time and concentration. Compared with the soaked black soybeans and cooked black soybeans, the fermented black soybeans with B. natto resulted in higher scavenging activity towards DPPH radicals, which correlated well with the content of total phenols (r = 0.9254, P natto fermented by B. natto has the potential to become a functional food because of its high antioxidant activity.

Effects of sorbitol and glycerol on the structure, dynamics, and stability of Mycobacterium tuberculosis pyrazinamidase

Directory of Open Access Journals (Sweden)

Mehrnoosh Khajehzadeh

2016-01-01

Conclusion: It can be concluded that the native conformation of the enzyme was stabilized in the sorbitol and glycerol and tend to exclude from the PZase surface, forcing the enzyme to keep it in the compactly folded conformation. The glycerol molecules stabilized PZase by decreasing the loops flexibility and then compacting the enzyme structure. It appears that more stability of PZase in glycerol solution correlates with its amphiphilic orientation, which decreases the unfavorable interactions of hydrophobic regions.

SOLID-STATE FERMENTATIVE PRODUCTION AND BIOACTIVITY OF FUNGAL CHITOSAN

Directory of Open Access Journals (Sweden)

Barry Aigbodion Omogbai

2013-10-01

Full Text Available Chitosan production was investigated using a laboratory-scale solid substrate fermentation (SSF technique with four species of fungi: Penicillium expansum, Aspergillus niger, Rhizopus oryzae and Fusarium moniliforme.The peak growth for the organisms was after 16 days. Aspergillus niger had the highest growth with a maximal dry cell biomass of 15.8g/kg after 16 days cultivation on corn straw under solid substrate fermentation. This was closely followed by Rhizopus oryzae (14.6g/kg, Penicillium expansum (13.8g/kg and Fusarium moniliforme (10.6g/kg respectively. The fungus Rhizopus oryzae had the highest chitosan production with a maximum of 8.57g/kg in 16 days under solid substrate fermentation (SSF with a medium containing corn straw. Aspergillus niger showed a modest chitosan yield of 6.8g/kg. Penicillium expansum and Fusarium moniliforme had low chitosan yields of 4.31g/kg and 3.1g/kg respectively. The degree of deacetylation of fungal chitosans ranged between 75.3-91.5% with a viscosity of 3.6-7.2 centipoises (Cp.Chitosan extracted from Rhizopus oryzae was found to have antibacterial activity on some bacterial isolates. At a concentration of 50mg/L, Rhizopus oryzae chitosan paralleled crab chitosan in susceptibility testing against some food-borne bacterial pathogens. Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and Bacillus subtilis showed inhibition rates of 83.2%, 67.9%, 63.8% and 62.4% respectively in response to 50mg/l Rhizopus oryzae chitosan in 24 h. The rate of inhibition (% increased with increase in chitosan concentration.

Estimation of hydrogen production in genetically modified E. coli fermentations using an artificial neural network

Energy Technology Data Exchange (ETDEWEB)

Rosales-Colunga, Luis Manuel; De Leon Rodriguez, Antonio [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Col. Lomas 4a secc, San Luis Potosi, SLP 78216 (Mexico); Garcia, Raul Gonzalez [Centro de Investigacion y Estudios de Posgrado, Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Dr. Manuel Nava 6, San Luis Potosi, SLP 78210 (Mexico)

2010-12-15

Biological hydrogen production is an active research area due to the importance of this gas as an energy carrier and the advantages of using biological systems to produce it. A cheap and practical on-line hydrogen determination is desired in those processes. In this study, an artificial neural network (ANN) was developed to estimate the hydrogen production in fermentative processes. A back propagation neural network (BPNN) of one hidden layer with 12 nodes was selected. The BPNN training was done using the conjugated gradient algorithm and on-line measurements of dissolved CO{sub 2}, pH and oxidation-reduction potential during the fermentations of cheese whey by Escherichia coli {delta}hycA {delta}lacI (WDHL) strain with or without pH control. The correlation coefficient between the hydrogen production determined by gas chromatography and the hydrogen production estimated by the BPNN was 0.955. Results showed that the BPNN successfully estimated the hydrogen production using only on-line parameters in genetically modified E. coli fermentations either with or without pH control. This approach could be used for other hydrogen production systems. (author)

High cell density cultivation of Escherichia coli K4 in a microfiltration bioreactor: a step towards improvement of chondroitin precursor production

Directory of Open Access Journals (Sweden)

De Rosa Mario

2011-02-01

Full Text Available Abstract Background The bacteria Escherichia coli K4 produces a capsular polysaccharide (K4 CPS whose backbone is similar to the non sulphated chondroitin chain. The chondroitin sulphate is one of the major components of the extra-cellular matrix of the vertebrate connective tissues and a high value molecule, widely employed as active principle in the treatment of osteoarthritis. It is usually obtained by extraction from animal tissues, but the risk of virus contaminations, as well as the scarceness of raw material, makes this productive process unsafe and unable to satisfy the growing market demand. In previous studies a new biotechnological process to produce chondroitin from Escherichia coli K4 capsular polysaccharide was investigated and a 1.4 g·L-1 K4 CPS concentration was reached using fed-batch fermentation techniques. In this work, on the trail of these results, we exploited new fermentation strategies to further improve the capsular polysaccharide production. Results The inhibitory effect of acetate on the bacterial cells growth and K4 CPS production was studied in shake flask conditions, while a new approach, that combined the optimization of the feeding profiles, the improvement of aeration conditions and the use of a microfiltration bioreactor, was investigated in three different types of fermentation processes. High polysaccharide concentrations (4.73 ± 0.2 g·L-1, with corresponding average yields (0.13 ± 0.006 gK4 CPS·gcdw-1, were obtained; the increase of K4 CPS titre, compared to batch and fed-batch results, was of 16-fold and 3.3-fold respectively, while average yield was almost 3.5 and 1.4 fold higher. Conclusion The increase of capsular polysaccharide titre confirmed the validity of the proposed fermentation strategy and opened the way to the use of the microfiltration bioreactor for the biotechnological production of chondroitin.

Microbial production of four biodegradable siderophores under submerged fermentation.

Science.gov (United States)

Fazary, Ahmed E; Al-Shihri, Ayed S; Alfaifi, Mohammad Y; Saleh, Kamel A; Alshehri, Mohammed A; Elbehairi, Serag Eldin I; Ju, Yi-Hsu

2016-07-01

Four siderophore analogues were isolated and purified from Escherichia coli, Bacillus spp. ST13, and Streptomyces pilosus microorganisms under some specific submerged fermentation conditions. In order to evaluate the highest production of this siderophore analogues through the growth, a rapid spectrophotometric screening semi-quantitative method was used, in which interestingly the analogues were isolated in its own form not its iron chelate. After chromatographic separation, the chemical structures of the isolated and purified siderophores were illustrated using detailed spectroscopic techniques. The biodegradation studies were done on that four novel isolated and purified siderophores following OECD protocols. In addition, the bioactivities of these siderophores and their iron complexes were examined and evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

Toward intensifying design of experiments in upstream bioprocess development: An industrial Escherichia coli feasibility study.

Science.gov (United States)

von Stosch, Moritz; Hamelink, Jan-Martijn; Oliveira, Rui

2016-09-01

In this study, step variations in temperature, pH, and carbon substrate feeding rate were performed within five high cell density Escherichia coli fermentations to assess whether intraexperiment step changes, can principally be used to exploit the process operation space in a design of experiment manner. A dynamic process modeling approach was adopted to determine parameter interactions. A bioreactor model was integrated with an artificial neural network that describes biomass and product formation rates as function of varied fed-batch fermentation conditions for heterologous protein production. A model reliability measure was introduced to assess in which process region the model can be expected to predict process states accurately. It was found that the model could accurately predict process states of multiple fermentations performed at fixed conditions within the determined validity domain. The results suggest that intraexperimental variations of process conditions could be used to reduce the number of experiments by a factor, which in limit would be equivalent to the number of intraexperimental variations per experiment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1343-1352, 2016. © 2016 American Institute of Chemical Engineers.

A quantitative study of methanol/sorbitol co-feeding process of a Pichia pastoris Mut⁺/pAOX1-lacZ strain.

Science.gov (United States)

Niu, Hongxing; Jost, Laurent; Pirlot, Nathalie; Sassi, Hosni; Daukandt, Marc; Rodriguez, Christian; Fickers, Patrick

2013-04-08

One of the main challenges for heterologous protein production by the methylotrophic yeast Pichia pastoris at large-scale is related to its high oxygen demand. A promising solution is a co-feeding strategy based on a methanol/sorbitol mixture during the induction phase. Nonetheless, a deep understanding of the cellular physiology and the regulation of the AOX1 promoter, used to govern heterologous protein production, during this co-feeding strategy is still scarce. Transient continuous cultures with a dilution rate of 0.023 h(-1) at 25°C were performed to quantitatively assess the benefits of a methanol/sorbitol co-feeding process with a Mut+ strain in which the pAOX1-lacZ construct served as a reporter gene. Cell growth and metabolism, including O2 consumption together with CO2 and heat production were analyzed with regard to a linear change of methanol fraction in the mixed feeding media. In addition, the regulation of the promoter AOX1 was investigated by means of β-galactosidase measurements. Our results demonstrated that the cell-specific oxygen consumption (qO2) could be reduced by decreasing the methanol fraction in the feeding media. More interestingly, maximal β-galactosidase cell-specific activity (>7500 Miller unit) and thus, optimal pAOX1 induction, was achieved and maintained in the range of 0.45 ~ 0.75 C-mol/C-mol of methanol fraction. In addition, the qO2 was reduced by 30% at most in those conditions. Based on a simplified metabolic network, metabolic flux analysis (MFA) was performed to quantify intracellular metabolic flux distributions during the transient continuous cultures, which further shed light on the advantages of methanol/sorbitol co-feeding process. Finally, our observations were further validated in fed-batch cultures. This study brings quantitative insight into the co-feeding process, which provides valuable data for the control of methanol/sorbitol co-feeding, aiming at enhancing biomass and heterologous protein productivities

Inactivation of enterohemorrhagic Escherichia coli in rumen content- or feces-contaminated drinking water for cattle.

Science.gov (United States)

Zhao, Tong; Zhao, Ping; West, Joe W; Bernard, John K; Cross, Heath G; Doyle, Michael P

2006-05-01

Cattle drinking water is a source of on-farm Escherichia coli O157:H7 transmission. The antimicrobial activities of disinfectants to control E. coli O157:H7 in on-farm drinking water are frequently neutralized by the presence of rumen content and manure that generally contaminate the drinking water. Different chemical treatments, including lactic acid, acidic calcium sulfate, chlorine, chlorine dioxide, hydrogen peroxide, caprylic acid, ozone, butyric acid, sodium benzoate, and competing E. coli, were tested individually or in combination for inactivation of E. coli O157:H7 in the presence of rumen content. Chlorine (5 ppm), ozone (22 to 24 ppm at 5 degrees C), and competing E. coli treatment of water had minimal effects (rumen content at water-to-rumen content ratios of 50:1 (vol/wt) and lower. Four chemical-treatment combinations, including (i) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.05% caprylic acid (treatment A); (ii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.1% sodium benzoate (treatment B); (iii) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 0.5% butyric acid (treatment C); and (iv) 0.1% lactic acid, 0.9% acidic calcium sulfate, and 100 ppm chlorine dioxide (treatment D); were highly effective (>3 log CFU/ml reduction) at 21 degrees C in killing E. coli O157:H7, O26:H11, and O111:NM in water heavily contaminated with rumen content (10:1 water/rumen content ratio [vol/wt]) or feces (20:1 water/feces ratio [vol/wt]). Among them, treatments A, B, and C killed >5 log CFU E. coli O157:H7, O26:H11, and O111:NM/ml within 30 min in water containing rumen content or feces, whereas treatment D inactivated approximately 3 to 4 log CFU/ml under the same conditions. Cattle given water containing treatment A or C or untreated water (control) ad libitum for two 7-day periods drank 15.2, 13.8, and 30.3 liters/day, respectively, and cattle given water containing 0.1% lactic acid plus 0.9% acidic calcium sulfate (pH 2.1) drank 18.6 liters/day. The

Biorefinery Concept Development Based on Wheat Flour Milling

Energy Technology Data Exchange (ETDEWEB)

Elliott, Douglas C.; Orth, Rick J.; Werpy, Todd A.; Gao, Johnway; Eakin, David E.; Schmidt, Andrew J.; Neuenschwander, Gary G.; Murry, J; Flagg, Anthony; Lahman, L; Mennel, D; Lin, C J.; Landucci, Ron; Crockett, John; Peterson, Charles L.

2002-09-22

We are developing an innovative process for the recovery of a starch-rich product from millfeed (the low-value byproduct of wheat flour milling); enzymatic processing of the starch to glucose; and the subsequent processes for conversion of that glucose into a value-added product by either a catalytic or a fermentation process. We have completed the development of the starch recovery step with enzymatic processing and the assessment of its economic viability. The processes to use the glucose product as feedstock for catalytic processing and fermentation processing have been tested in the laboratory. Catalytic processing of the glucose from the extracted starch for polyol production is based on catalytic hydrogenation to sorbitol. Alternatively, fermentation of the extracted starch-derived glucose also provides a pathway to value-added chemical products via a platform chemical, lactic acid. The paper includes results from all the processing areas addressed. Starch extraction and glucose generation from wheat milling byproducts are presented with laboratory and scaled-up processing results. Results of fermentation of the glucose product to lactic acid in shaker flask tests are presented, documenting the minimal requirements for nutrient addition. Stirred batch reactor tests of catalytic hydrogenation of the glucose product to sorbitol are presented with a discussion of contaminant effects on the catalyst.

A 1000-L Scale-Up Fermentation of Escherichia Coli Containing PVSEOP7 for Production of Organophosphorus Hydrolase

National Research Council Canada - National Science Library

Lukens, Dennis C; Rastogi, Vipin K; Cheng, Tu-c; DeFrank, Joseph J; Valdes, James J; Kim, Michael H

2003-01-01

.... coli XL1 containing pVSEOP7. The specific OPH activity was monitored during each 20-L batch fermentation culture by assaying several times between the IPTG induction point (OD of 0.4 to 0.5 at 600 nm...

Association of prescription of oral sodium polystyrene sulfonate with sorbitol in an inpatient setting with colonic necrosis: a retrospective cohort study.

Science.gov (United States)

Watson, Maura A; Baker, Thomas P; Nguyen, Annie; Sebastianelli, Mary E; Stewart, Heather L; Oliver, David K; Abbott, Kevin C; Yuan, Christina M

2012-09-01

Colonic necrosis has been reported after sodium polystyrene sulfonate (SPS)/sorbitol use, but the incidence and relative risk (RR) are not established. Retrospective cohort study. 123,391 adult inpatients at a tertiary medical center. Receipt of SPS prescriptions (exposed) or a prescription other than SPS (unexposed internal comparison group) between September 1, 2001, and October 31, 2010. The main outcome measure was tissue-confirmed diagnosis of colonic necrosis, considered SPS-associated if SPS was prescribed 30 or fewer days before tissue accession date. Demographics, serum chemistry test results, hospital location, and International Classification of Diseases, Ninth Revision diagnostic codes. SPS was prescribed to 2,194 inpatients. 82 inpatient colonic necrosis cases were identified. 3 received oral SPS (1 gram per 4 milliliters of 33% sorbitol) 30 or fewer days before the colonic necrosis accession date (3.7% of inpatient colonic necrosis cases). The data were linked with 123,391 individuals who received inpatient prescriptions between the same dates. Colonic necrosis incidence was 0.14% (95% CI, 0.03%-0.40%) in those prescribed SPS versus 0.07% (95% CI, 0.05-0.08%) in those not prescribed SPS (RR, 2.10; 95% CI, 0.68-6.48; P = 0.2). The number needed to harm was 1,395 (95% CI, 298-5,100). Subgroup analysis (age >65 years; estimated glomerular filtration rate, sorbitol prescription was not associated significantly with an increased RR of colonic necrosis in this retrospective cohort analysis. Multivariate analysis would require retrospective clinical cohorts from larger or more than one hospital system(s). Published by Elsevier Inc.

The Quality of Liquid Fermented Products for Alternative Use of Antibiotics for Animal Raising

Energy Technology Data Exchange (ETDEWEB)

Piadang, Nattaya [Office of Atoms for Peace, Bangkok (Thailand)

2006-09-15

The chemical properties of liquid fermented products (LFP) as probiotics substance for alternative uses of antibiotic were studied. The LFP of 235 were sampling from markets and farmers during 2005-2006. The total count of bacteria, fungi, lactic acid bacteria (LAB), Actinomyces and coliform bacteria were conducted. Chemical analysis of LFP showed medium nitrogen (0.01- 0.55%), maximum sugar contents (0.02 - 19.40%), high lactic acid contents (0.34 - 13.01%) and low pH (2.9-5.0). LFPs were free from fecal coliform and Escherichia coil (Ec); but in LAB (1.0 - 1.25x10{sup 7} cfu/ml) and high Actinomyces (1.0 - 7.5 x 10{sup 6} cfu/ml). LFPs inhibited Staphylococcus aureus (Sa), Samonella typhimurium (STM), Escherichia coil (Ec) and Ec 0157 at maximum yield by using Minimal Inhibition Concentration (MIC). But Pseudomonas aeruginosa (Pa) could medium inhibited. Therefore LFP samples are suitable as probiotics for alternative use of antibiotic for animal raising.

The Quality of Liquid Fermented Products for Alternative Use of Antibiotics for Animal Raising

International Nuclear Information System (INIS)

Piadang, Nattaya

2006-09-01

The chemical properties of liquid fermented products (LFP) as probiotics substance for alternative uses of antibiotic were studied. The LFP of 235 were sampling from markets and farmers during 2005-2006. The total count of bacteria, fungi, lactic acid bacteria (LAB), Actinomyces and coliform bacteria were conducted. Chemical analysis of LFP showed medium nitrogen (0.01- 0.55%), maximum sugar contents (0.02 - 19.40%), high lactic acid contents (0.34 - 13.01%) and low pH (2.9-5.0). LFPs were free from fecal coliform and Escherichia coil (Ec); but in LAB (1.0 - 1.25x10 7 cfu/ml) and high Actinomyces (1.0 - 7.5 x 10 6 cfu/ml). LFPs inhibited Staphylococcus aureus (Sa), Samonella typhimurium (STM), Escherichia coil (Ec) and Ec 0157 at maximum yield by using Minimal Inhibition Concentration (MIC). But Pseudomonas aeruginosa (Pa) could medium inhibited. Therefore LFP samples are suitable as probiotics for alternative use of antibiotic for animal raising.

The effect of the addition of sorbitol and glycerol towards the edible film characteristics of the belitung taro starch and the lime leaves as antimicrobial

Science.gov (United States)

Asria, Merry; Elizarni, Samah, dan Selfa Dewati

2015-12-01

Plastics have been generally used for food packaging, but plastics using causing environmental problem for as non biodegradable. Resolving the problem need another alternative packaging that environmental friendly such as the edible film as biodegradable packing material. This research intend to determination the effects of sorbitol and glycerol (concentration of 1%, 2%, 3%, and 4%) as addition to the edible film characteristics from the belitung taro starch (Xanthosoma sagitifolium). Lime leaves (Citrus aurantifolia) extract used as an antimicrobial film (2%, 4%, 6%, 8%, and 10% respectively). From the research obtained that using sorbitol has given more rigid and hard film texture, while glycerol provides more elastic and flexible texture. Sorbitol give best performance at 2% where thickness 0.17 mm; tensile strength 41.60 MPa; yield strength 34.28 MPa; modulus of elasticity 7983.71 MPa; and maximum strain 29,8%. While, glycerol (2%) provides thickness 0.18 mm; tensile strength 35.72 MPa; yield strength 30.78 MPa; modulus of elasticity 9065.90 MPa; and maximum strain 14.4% for best performance. SEM and FTIR analysis applied to determine film surface morphology's characterization and determine the functional groups of the film materials. The addition of lime leaves extract as antimicrobial gives the growth inhibition activity against the Staphylococcus aureus bacteria.

Influence of pre-fermentation cold maceration treatment on aroma compounds of Cabernet Sauvignon wines fermented in different industrial scale fermenters.

Science.gov (United States)

Cai, Jian; Zhu, Bao-Qing; Wang, Yun-He; Lu, Lin; Lan, Yi-Bin; Reeves, Malcolm J; Duan, Chang-Qing

2014-07-01

The influence of pre-fermentation cold maceration (CM) on Cabernet Sauvignon wines fermented in two different industrial-scale fermenters was studied. CM treatment had different effects on wine aroma depending on the types of fermenter, being more effective for automatic pumping-over tank (PO-tank) than automatic punching-down tank (PD-tank). When PO-tank was used, CM-treated wine showed a decrease in some fusel alcohols (isobutanol and isopentanol) and an increase in some esters (especially acetate esters). However, no significant changes were detected in these compounds when PD-tank was used. Ethyl 2-hexenoate and diethyl succinate were decreased, while geranylacetone was increased by the CM treatment in both fermenters. β-Damascenone was increased by the CM treatment in PO-tank fermented wines but decreased in PD-tank fermented wines. The fruity, caramel and floral aroma series were enhanced while chemical series were decreased by the CM treatment in PO-tank fermented wines. The content of (Z)-6-nonen-1-ol in the final wines was positively correlated to CM treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of the {sup 14}C-labeled insecticidal protein Cry1Ab for soil metabolic studies using a recombinant Escherichia coli in small-scale batch fermentations

Energy Technology Data Exchange (ETDEWEB)

Valldor, Petra; Miethling-Graff, Rona; Dockhorn, Susanne; Martens, Rainer; Tebbe, Christoph C. [Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig (Germany). Thuenen Institute (vTI) for Biodiversity

2012-10-15

Insecticidal Cry proteins naturally produced by Bacillus thuringiensis are a major recombinant trait expressed by genetically modified crops. They are released into the soil during and after cropping. The objective of this study was to produce {sup 14}C-labeled Cry1Ab proteins for soil metabolic studies in scope of their environmental risk assessment. Cry1Ab was synthesized as a protoxin by Escherichia coli HB101 pMP in 200-mL liquid batch culture fermentations and purified from inclusion bodies after trypsin digestion. For cultivation, U-{sup 14}C-glycerol was the main carbon source. Inclusion bodies were smaller and Cry1Ab yield was lower when the initial amount of total organic carbon in the cultivation broth was below 6.4 mg C L{sup -1}. Concentrations of 12.6 g {sup 14}C-labeled glycerol L{sup -1} (1 % v/v) resulted in the production of 17.1 mg {sup 14}C-Cry1Ab L{sup -1} cultivation medium. {sup 14}C mass balances showed that approx. 50 % of the label was lost by respiration and 20 % remained in the growth media, while the residual activity was associated with biomass. Depending on the production batch, 0.01 to 0.05 % of the total {sup 14}C originated from Cry1Ab. In the presence of 2.04 MBq {sup 14}C-labeled carbon sources, a specific activity of up to 268 Bq mg{sup -1} {sup 14}C-Cry1Ab was obtained. A more than threefold higher specific activity was achieved with 4.63 MBq and an extended cultivation period of 144 h. This study demonstrates that {sup 14}C-labeled Cry1Ab can be obtained from batch fermentations with E. coli in the presence of a simple {sup 14}C-labeled carbon source. It also provides a general strategy to produce {sup 14}C-labeled proteins useful for soil metabolic studies. (orig.)

GUT FERMENTATION SYNDROME

African Journals Online (AJOL)

boaz

individuals who became intoxicated after consuming carbohydrates, which became fermented in the gastrointestinal tract. These claims of intoxication without drinking alcohol, and the findings on endogenous alcohol fermentation are now called Gut. Fermentation Syndrome. This review will concentrate on understanding ...

Identifying mechanisms by which Escherichia coli O157:H7 subverts interferon-γ mediated signal transducer and activator of transcription-1 activation.

Directory of Open Access Journals (Sweden)

Nathan K Ho

Full Text Available Enterohemorrhagic Escherichia coli serotype O157:H7 is a food borne enteric bacterial pathogen that causes significant morbidity and mortality in both developing and industrialized nations. E. coli O157:H7 infection of host epithelial cells inhibits the interferon gamma pro-inflammatory signaling pathway, which is important for host defense against microbial pathogens, through the inhibition of Stat-1 tyrosine phosphorylation. The aim of this study was to determine which bacterial factors are involved in the inhibition of Stat-1 tyrosine phosphorylation. Human epithelial cells were challenged with either live bacteria or bacterial-derived culture supernatants, stimulated with interferon-gamma, and epithelial cell protein extracts were then analyzed by immunoblotting. The results show that Stat-1 tyrosine phosphorylation was inhibited by E. coli O157:H7 secreted proteins. Using sequential anion exchange and size exclusion chromatography, YodA was identified, but not confirmed to mediate subversion of the Stat-1 signaling pathway using isogenic mutants. We conclude that E. coli O157:H7 subverts Stat-1 tyrosine phosphorylation in response to interferon-gamma through a still as yet unidentified secreted bacterial protein.

Isolation and characteristics of Shiga toxin 2f-producing Escherichia coli among pigeons in Kyushu, Japan.

Directory of Open Access Journals (Sweden)

Koichi Murakami

Full Text Available An increasing number of Shiga toxin 2f-producing Escherichia coli (STEC2f infections in humans are being reported in Europe, and pigeons have been suggested as a reservoir for the pathogen. In Japan, there is very little information regarding carriage of STEC2f by pigeons, prompting the need for further investigation. We collected 549 samples of pigeon droppings from 14 locations in Kyushu, Japan, to isolate STEC2f and to investigate characteristics of the isolates. Shiga toxin stx 2f gene fragments were detected by PCR in 16 (2.9% of the 549 dropping samples across four of the 14 locations. We obtained 23 STEC2f-isolates from seven of the original samples and from three pigeon dropping samples collected in an additional sampling experiment (from a total of seven locations across both sampling periods. Genotypic and phenotypic characteristics were then examined for selected isolates from each of 10 samples with pulsed-field gel electrophoresis profiles. Eight of the stx 2f gene fragments sequenced in this study were homologous to others that were identified in Europe. Some isolates also contained virulence-related genes, including lpfA O26, irp 2, and fyuA, and all of the 10 selected isolates maintained the eae, astA, and cdt genes. Moreover, five of the 10 selected isolates contained sfpA, a gene that is restricted to Shiga toxin-producing E. coli O165:H2 and sorbitol-fermenting Shiga toxin-producing E. coli O157:NM. We document serotypes O152:HNM, O128:HNM, and O145:H34 as STEC2f, which agrees with previous studies on pigeons and humans. Interestingly, O119:H21 was newly described as STEC2f. O145:H34, with sequence type 722, was described in a German study in humans and was also isolated in the current study. These results revealed that Japanese zoonotic STEC2f strains harboring several virulence-related factors may be of the same clonal complexes as some European strains. These findings provide useful information for public health

Fermented Aloreña Table Olives as a Source of Potential Probiotic Lactobacillus pentosus Strains.

Science.gov (United States)

Montoro, Beatriz Pérez; Benomar, Nabil; Lavilla Lerma, Leyre; Castillo Gutiérrez, Sonia; Gálvez, Antonio; Abriouel, Hikmate

2016-01-01

A collection of 31 Lactobacillus pentosus strains isolated from naturally fermented Aloreña green table olives were screened in depth in the present study for their probiotic potential. Several strains could be considered promising probiotic candidates since they showed good growth capacity and survival under simulated gastro-intestinal conditions (acidic pH of 1.5, up to 4% of bile salts and 5 mM of nitrate), good ability to auto-aggregate which may facilitate their adhesion to host cells as multiple aggregates and the subsequent displacement of pathogens. Moreover, co-aggregation of lactobacilli with pathogenic bacteria was shown with Listeria innocua, Staphylococcus aureus, Escherichia coli , and Salmonella Enteritidis as good defense strategy against gut and food pathogens. Furthermore, they exhibited adherence to intestinal and vaginal cell lines, such property could be reinforced by their capacity of biofilm formation which is also important in food matrices such as the olive surface. Their antagonistic activity against pathogenic bacteria by means of acids and plantaricins, and also their different functional properties may determine their efficacy not only in the gastro-intestinal tract but also in food matrices. Besides their ability to ferment several prebiotics, the new evidence in the present study was their capacity to ferment lactose which reinforces their use in different food matrices including dairy as a dietary adjunct to improve lactose digestibility. Lactobacillus pentosus CF2-10N was selected to have the best probiotic profile being of great interest in further studies. In conclusion, spontaneous fermented Aloreña table olives are considered a natural source of potential probiotic L. pentosus to be included as adjunct functional cultures in different fermented foods.

Fermented Aloreña table olives as a source of potential probiotic Lactobacillus pentosus strains

Directory of Open Access Journals (Sweden)

Beatriz Pérez Montoro

2016-10-01

Full Text Available A collection of 31 Lactobacillus pentosus strains isolated from naturally fermented Aloreña green table olives were screened in depth in the present study for their probiotic potential. Several strains could be considered promising probiotic candidates since they showed good growth capacity and survival under simulated gastro-intestinal conditions (acidic pH of 1.5, up to 4% of bile salts and 5 mM of nitrate, good ability to auto-aggregate which may facilitate their adhesion to host cells as multiple aggregates and the subsequent displacement of pathogens. Moreover, co-aggregation of lactobacilli with pathogenic bacteria was shown with Listeria innocua, Staphylococcus aureus, Escherichia coli and Salmonella Enteriditis as good defense strategy against gut and food pathogens. Furthermore, they exhibited adherence to intestinal and vaginal cell lines, such property could be reinforced by their capacity of biofilm formation which is also important in food matrices such as the olive surface. Their antagonistic activity against pathogenic bacteria by means of acids and plantaricins, and also their different functional properties may determine their efficacy not only in the gastro-intestinal tract but also in food matrices. Besides their ability to ferment several prebiotics, the new evidence in the present study was their capacity to ferment lactose which reinforces their use in different food matrices including dairy as a dietary adjunct to improve lactose digestibility. Lactobacillus pentosus CF2-10N was selected to have best probiotic profile being of great interest in further studies. In conclusion, spontaneous fermented Aloreña table olives are considered a natural source of potential probiotic Lb. pentosus to be included as adjunct functional cultures in different fermented foods.

Radiolysis of carbohydrates as studied by ESR and spin-trapping—II. Glycerol- d8 xylitol, dulcitol, d-sorbitol and d-mannitol

Science.gov (United States)

Kuwabara, M.; Zhang, Z.-Y.; Inanami, O.; Yoshii, G.

Studies concerning the radicals produced in glycerol by reactions with OH radicals have been carried out by investigating deuterated glycerol (glycerol-d 8) by spin-trapping with 2-methyl-2-nitrosopropane. Free radicals produced in linear carbohydrates such as xylitol, dulcitol, D-sorbitol and D-mannitol by reactions with OH radicals as well as by direct γ-radiolysis have been also investigated by spin-trapping. The ESR spectra of the spin-trapped radicals were analysed on the basis of the results from ESR and spin-trapping experiments on glycerol and deuterated glycerol, and the formation of three radical species, CHO-CH-, CH 2-CO- and HO-CH-, due to both OH reactions and direct γ-radiolysis was confirmed for all compounds. The presence of a radical, -CO-CH-, was detected for xylitol, D-sorbitol and D-mannitol. General reactions processes induced by OH reactions or γ-radiolysis in the solid state are discussed.

Intestinal Pathogenic Escherichia coli: Insights for Vaccine Development

Directory of Open Access Journals (Sweden)

Maricarmen Rojas-Lopez

2018-03-01

Full Text Available Diarrheal diseases are one of the major causes of mortality among children under five years old and intestinal pathogenic Escherichia coli (InPEC plays a role as one of the large causative groups of these infections worldwide. InPECs contribute significantly to the burden of intestinal diseases, which are a critical issue in low- and middle-income countries (Asia, Africa and Latin America. Intestinal pathotypes such as enteropathogenic E. coli (EPEC and enterotoxigenic E. coli (ETEC are mainly endemic in developing countries, while ETEC strains are the major cause of diarrhea in travelers to these countries. On the other hand, enterohemorrhagic E. coli (EHEC are the cause of large outbreaks around the world, mainly affecting developed countries and responsible for not only diarrheal disease but also severe clinical complications like hemorrhagic colitis and hemolytic uremic syndrome (HUS. Overall, the emergence of antibiotic resistant strains, the annual cost increase in the health care system, the high incidence of traveler diarrhea and the increased number of HUS episodes have raised the need for effective preventive treatments. Although the use of antibiotics is still important in treating such infections, non-antibiotic strategies are either a crucial option to limit the increase in antibiotic resistant strains or absolutely necessary for diseases such as those caused by EHEC infections, for which antibiotic therapies are not recommended. Among non-antibiotic therapies, vaccine development is a strategy of choice but, to date, there is no effective licensed vaccine against InPEC infections. For several years, there has been a sustained effort to identify efficacious vaccine candidates able to reduce the burden of diarrheal disease. The aim of this review is to summarize recent milestones and insights in vaccine development against InPECs.

Principales características y diagnóstico de los grupos patógenos de Escherichia coli Diagnosis and main characteristics of Escherichia coli pathogenic groups

Directory of Open Access Journals (Sweden)

Guadalupe Rodríguez-Angeles

2002-09-01

Full Text Available Escherichia coli coloniza el intestino del hombre pocas horas después del nacimiento y se considera de flora normal, pero hay descritos seis grupos de E. coli productora de diarrea: enterotoxigénica (ETEC, enterohemorrágica (EHEC, enteroinvasiva (EIEC, enteropatógena (EPEC, enteroagregativa (EAEC y de adherencia difusa (DAEC. La bacteria se puede aislar e identificar tradicionalmente con base en sus características bioquímicas o serológicas, pero también se pueden estudiar sus mecanismos de patogenicidad mediante ensayos en cultivos celulares o modelos animales y, más recientemente, empleando técnicas de biología molecular que evidencian la presencia de genes involucrados en dichos mecanismos. La intención del presente trabajo es resaltar la importancia del estudio y diagnóstico de E. coli como patógeno capaz de causar casos aislados o brotes de diarrea, síndrome urémico hemolítico, colitis hemorrágica y cuadros de disentería, principalmente en niños; por esto es necesario conocer mejor a la bacteria y mantener la vigilancia epidemiológica.Escherichia coli colonizes the human intestinal tract within hours of birth and is considered a non-pathogenic member of the normal intestinal flora. However, there are six pathogenic groups that may produce diarrhea: enterotoxigenic (ETEC, enterohemorrhagic (EHEC, enteroinvasive (EIEC, enteropathogenic (EPEC, enteroaggregative (EAEC and diffusely adherent (DAEC groups. E. coli can be isolated and classified using traditional methods, by identifying its biochemical or serum characteristics. The pathogenic mechanisms may be studied in cell cultures and animal model assays, as well as more up to date molecular biology methods for study and diagnosis. The latter have proven that genes are involved in pathogenesis. The objective of the present work is to draw attention to the importance of E. coli as a pathogenic organism. This microorganism is an etiologic agent of sporadic cases of diarrhea

Escherichia coli O157:H7 bacteriophage 241 isolated from an industrial cucumber fermentation at high acidity and salinity

Directory of Open Access Journals (Sweden)

Zhongjing eLu

2015-02-01

Full Text Available A novel phage, 241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH  3.7 and salinity ( 5% NaCl were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7 or the 2 O antigen-negative mutants of O157:H7 strain, 43895per (also lacking H7 antigen and F12 (still expressing H7 antigen. However, the phage was able to lyse a per-complemented strain (43895perComp which expresses O157 antigen. These results indicated that phage 241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3 or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage 241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment.

Best combination of promoter and micellar catalyst for the rapid conversion of sorbitol to glucose

Science.gov (United States)

Mukherjee, Kakali; Ghosh, Aniruddha; Saha, Rumpa; Sar, Pintu; Malik, Susanta; Saha, Bidyut

2014-03-01

Kinetic data for oxidation of D-sorbitol to glucose by hexavalent chromium in aqueous medium and aqueous surfactant medium (SDS, TX-100) have been reported. Effect of promoter such as PA, bipy and phenanthroline on the reaction has been investigated. The reaction is performed under pseudo first order condition with an excess of substrate over the oxidant. The reaction is first order with respect to substrate and oxidant. The micelles have a catalytic effect on the reaction. Combination of phen and TX-100 produces almost twelve times increase in rate of oxidation.

Lactose fermentation by engineered Saccharomyces cerevisiae capable of fermenting cellobiose.

Science.gov (United States)

Liu, Jing-Jing; Zhang, Guo-Chang; Oh, Eun Joong; Pathanibul, Panchalee; Turner, Timothy L; Jin, Yong-Su

2016-09-20

Lactose is an inevitable byproduct of the dairy industry. In addition to cheese manufacturing, the growing Greek yogurt industry generates excess acid whey, which contains lactose. Therefore, rapid and efficient conversion of lactose to fuels and chemicals would be useful for recycling the otherwise harmful acid whey. Saccharomyces cerevisiae, a popular metabolic engineering host, cannot natively utilize lactose. However, we discovered that an engineered S. cerevisiae strain (EJ2) capable of fermenting cellobiose can also ferment lactose. This finding suggests that a cellobiose transporter (CDT-1) can transport lactose and a β-glucosidase (GH1-1) can hydrolyze lactose by acting as a β-galactosidase. While the lactose fermentation by the EJ2 strain was much slower than the cellobiose fermentation, a faster lactose-fermenting strain (EJ2e8) was obtained through serial subcultures on lactose. The EJ2e8 strain fermented lactose with a consumption rate of 2.16g/Lh. The improved lactose fermentation by the EJ2e8 strain was due to the increased copy number of cdt-1 and gh1-1 genes. Looking ahead, the EJ2e8 strain could be exploited for the production of other non-ethanol fuels and chemicals from lactose through further metabolic engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Quality and Composition of Red Wine Fermented with Schizosaccharomyces pombe as Sole Fermentative Yeast, and in Mixed and Sequential Fermentations with Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Felipe Palomero

2014-01-01

Full Text Available This work examines the physiology of Schizosaccharomyces pombe (represented by strain 938 in the production of red wine, as the sole fermentative yeast, and in mixed and sequential fermentations with Saccharomyces cerevisiae 796. For further comparison, fermentations in which Saccharomyces cerevisiae was the sole fermentative yeast were also performed; in these fermentations a commercial lactic acid bacterium was used to perform malolactic fermentation once alcoholic fermentation was complete (unlike S. cerevisiae, the Sc. pombe performs maloalcoholic fermentation and therefore removes malic acid without such help. Relative density, acetic, malic and pyruvic acid concentrations, primary amino nitrogen and urea concentrations, and pH of the musts were measured over the entire fermentation period. In all fermentations in which Sc. pombe 938 was involved, nearly all the malic acid was consumed from an initial concentration of 5.5 g/L, and moderate acetic acid concentrations below 0.4 g/L were formed. The urea content of these wines was notably lower, showing a tenfold reduction when compared with those that were made with S. cerevisiae 796 alone. The sensorial properties of the different final wines varied widely. The wines fermented with Sc. pombe 938 had maximum aroma intensity and quality, and they were preferred by the tasters.

Protein concentrations of sweet soysauces from Rhizopus oryzae and R. oligosporus fermentation without moromi fermentation

Directory of Open Access Journals (Sweden)

NOOR SOESANTI HANDAJANI

2007-07-01

Full Text Available Soy sauce was produce from soybean that fermented with koji/tempeh fungi and thenfermented under salt solution or moromi fermentation. The objectives of this experiment was to compare of protein (total and soluble content of sweet soy sauce that produced from soybean fermented with Rhizopus oryzae and R. oligosporus without moromi fermentation to the sweet soysauce with moromi fermentation one. The total and soluble proteins of sweet soy sauces that produce from soybean without moromi fermentation were higher that sweet soy sauces that produce with moromi fermentation. Soluble protein of sweet soy sauce that produced from soybean fermented with R. oligosporus without moromi fermentation was 8.2% and meet to the highest quality of sweet soy sweet sauce based on Indonesia Industrial Standard. Soluble protein of sweet soy sauce that produced from soybean fermented with R. oryzae without moromi fermentation was 4.1% and meet to the medium quality of sweet soy sweet sauce based on Indonesia Industrial Standard.

Development of lotus root fermented sugar syrup as a functional food supplement/condiment and evaluation of its physicochemical, nutritional and microbiological properties.

Science.gov (United States)

Shukla, Shruti; Park, Juyeon; Park, Jung Hyun; Lee, Jong Suk; Kim, Myunghee

2018-02-01

Lotus ( Nelumbo nucifera ) root has been used as an edible vegetable in East Asia for thousands of years. The present research was aimed to explore the physicochemical, nutritional and microbiological safety of lotus root fermented sugar syrup as a fermented food supplement or condiment for human health benefits. In this study, the physicochemical, nutritional and microbiological safety properties of lotus root syrup fermented with 57° Brix brown sugar at different time periods until 6 months (180 days) was investigated. There was a significant improvement as compared to 57° Brix brown sugar broth (as a control) in the total acceptability and physicochemical properties of lotus root sugar syrup samples such as pH and color improvement. The red color values of 180 days lotus root fermented sugar syrup samples were significantly enhanced (6.85 ± 0.58) when compared with the control (0.20 ± 0.15). In addition, the total protein content was increased from 8.27 ± 0.86 to 392.33 ± 7.19 μg/mL, along with the increase in fermentation time reaching to the level of consumption acceptability. All the lotus root fermented sugar syrup samples were subjected to microbiological analysis. It was found that the coliform, Bacillus cereus , Escherichia coli , Salmonella and Staphylococcus aureus counts were not detected in majority of the samples, confirming the high degree of hygiene processing of lotus root fermented sugar syrup samples for its use as a food supplement or condiment.

Solid substrate fermentation

Energy Technology Data Exchange (ETDEWEB)

Tengerdy, R P

1985-04-01

Solid Substrate Fermentation (SSF) describes the microbiological tranformation of biological materials in their natural state, in contrast with liquid or submerged fermentations which are carried out in dilute solutions or slurries. The most important industrial microorganisms used in SSF are filamentous fungi and the critical factors in their growth are the control of the moisture level and the temperature. Traditionally, most SSFs are conducted in shallow trays (so that heat build up is avoided) and stacked in a moist chamber, however, the modern SSF should be able to mix large amounts of substrate for a uniform fermentation, maximum automization scale-up of the process, continuous operation and fermentation control and a promising new design is the Helical screw fermenter. At the present time SSF is used in the production of foods (e.g. mushrooms and oriental foods) in municipal, agricultural and industrial solid waste disposal and in the production of enzymes and speciality chemicals but it does not seem likely that it will replace prevalent liquid fermentation technologies. 29 references.

Defective quiescence entry promotes the fermentation performance of bottom-fermenting brewer's yeast.

Science.gov (United States)

Oomuro, Mayu; Kato, Taku; Zhou, Yan; Watanabe, Daisuke; Motoyama, Yasuo; Yamagishi, Hiromi; Akao, Takeshi; Aizawa, Masayuki

2016-11-01

One of the key processes in making beer is fermentation. In the fermentation process, brewer's yeast plays an essential role in both the production of ethanol and the flavor profile of beer. Therefore, the mechanism of ethanol fermentation by of brewer's yeast is attracting much attention. The high ethanol productivity of sake yeast has provided a good basis from which to investigate the factors that regulate the fermentation rates of brewer's yeast. Recent studies found that the elevated fermentation rate of sake Saccharomyces cerevisiae species is closely related to a defective transition from vegetative growth to the quiescent (G 0 ) state. In the present study, to clarify the relationship between the fermentation rate of brewer's yeast and entry into G 0 , we constructed two types of mutant of the bottom-fermenting brewer's yeast Saccharomyces pastorianus Weihenstephan 34/70: a RIM15 gene disruptant that was defective in entry into G 0 ; and a CLN3ΔPEST mutant, in which the G 1 cyclin Cln3p accumulated at high levels. Both strains exhibited higher fermentation rates under high-maltose medium or high-gravity wort conditions (20° Plato) as compared with the wild-type strain. Furthermore, G 1 arrest and/or G 0 entry were defective in both the RIM15 disruptant and the CLN3ΔPEST mutant as compared with the wild-type strain. Taken together, these results indicate that regulation of the G 0 /G 1 transition might govern the fermentation rate of bottom-fermenting brewer's yeast in high-gravity wort. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels

Directory of Open Access Journals (Sweden)

Xuefang Guan

Full Text Available ABSTRACT Objective To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. Methods The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. Results The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940 and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v in simulated gastric juice (pH 2.5 for 2 h and in simulated intestinal fluid (pH 8.0 for 3 h. The auto-aggregation rate increased to 87.74% after 24 h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. Conclusion These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health.

Sequential enzymatic saccharification and fermentation of ionic liquid and organosolv pretreated agave bagasse for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Pérez-Pimienta, Jose A. [Univ. Autonoma de Nayarit, Tepic (Mexico); Vargas-Tah, Alejandra [Univ. Nacional Autonoma de Mexico (UNAM), Cuernavaca (Mexico).; López-Ortega, Karla M. [Univ. Autonoma de Nayarit, Tepic (Mexico); Medina-López, Yessenia N. [Univ. Autonoma de Nayarit, Tepic (Mexico); Mendoza-Pérez, Jorge A. [Inst. Politecnico Nacional (IPN), Mexico City (Mexico); Avila, Sayeny [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Singh, Seema [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Simmons, Blake A. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Loaces, Inés [Univ. Nacional Autonoma de Mexico (UNAM), Cuernavaca (Mexico).; Martinez, Alfredo [Univ. Nacional Autonoma de Mexico (UNAM), Cuernavaca (Mexico).

2016-11-16

Agave bagasse (AGB) has gained recognition as a drought-tolerant biofuel feedstock with high productivity in semiarid regions. A comparative analysis of ionic liquid (IL) and organosolv (OV) pretreatment technologies in AGB was performed using a sequential enzymatic saccharification and fermentation (SESF) strategy with cellulolytic enzymes and the ethanologenic Escherichia coli strain MS04. After pretreatment, 86% of xylan and 45% of lignin were removed from OV-AGB, whereas IL-AGB reduced lignin content by 28% and xylan by 50% when compared to the untreated biomass. High glucan ( > 90%) and xylan ( > 83%) conversion was obtained with both pretreated samples. During the fermentation stage (48 h), 12.1 and 12.7 kg of ethanol were produced per 100 kg of untreated AGB for IL and OV, respectively. These comparative analyses showed the advantages of SESF using IL and OV in a biorefinery configuration where a better understanding of AGB recalcitrance is key for future applications.

Citric acid fermentation by gamma ray induced mutants of Aspergillus niger in different carbohydrate media

Energy Technology Data Exchange (ETDEWEB)

Anjuman Ara Begum; Naiyyum Choudhury; Mohammad Serajul Islam (Institute of Food and Radiation Biology, Dacca (Bangladesh))

1990-01-01

A natural isolate of Aspergillus niger, CA16, and two of its second step mutants, 136/40 and 277/30, grown on different sugar substrates gave maximum citric acid yields of 34, 70, and 126 mg/ml respectively in sucrose medium. Combination of two sugars in the medium at 50% of each improved the yields of citric acid for the sucrose: glucose, glucose: sorbitol, glucose: xylose, and xylose: sorbitol combinations with the mutant strains. Inclusion of galactose in combinations decreased the citric acid yield. (author).

Citric acid fermentation by gamma ray induced mutants of Aspergillus niger in different carbohydrate media

International Nuclear Information System (INIS)

Anjuman Ara Begum; Naiyyum Choudhury; Mohammad Serajul Islam

1990-01-01

A natural isolate of Aspergillus niger, CA16, and two of its second step mutants, 136/40 and 277/30, grown on different sugar substrates gave maximum citric acid yields of 34, 70, and 126 mg/ml respectively in sucrose medium. Combination of two sugars in the medium at 50% of each improved the yields of citric acid for the sucrose: glucose, glucose: sorbitol, glucose: xylose, and xylose: sorbitol combinations with the mutant strains. Inclusion of galactose in combinations decreased the citric acid yield. (author)

Metabolic engineering of Escherichia coli for biotechnological production of high-value organic acids and alcohols

Energy Technology Data Exchange (ETDEWEB)

Yu, Chao; Cao, Yujin; Zou, Huibin; Xian, Mo [Chinese Academy of Sciences, Qingdao (China). Key Lab. of Biofuels

2011-02-15

Confronted with the gradual and inescapable exhaustion of the earth's fossil energy resources, the bio-based process to produce platform chemicals from renewable carbohydrates is attracting growing interest. Escherichia coli has been chosen as a workhouse for the production of many valuable chemicals due to its clear genetic background, convenient to be genetically modified and good growth properties with low nutrient requirements. Rational strain development of E. coli achieved by metabolic engineering strategies has provided new processes for efficiently biotechnological production of various high-value chemical building blocks. Compared to previous reviews, this review focuses on recent advances in metabolic engineering of the industrial model bacteria E. coli that lead to efficient recombinant biocatalysts for the production of high-value organic acids like succinic acid, lactic acid, 3-hydroxypropanoic acid and glucaric acid as well as alcohols like 1,3-propanediol, xylitol, mannitol, and glycerol with the discussion of the future research in this area. Besides, this review also discusses several platform chemicals, including fumaric acid, aspartic acid, glutamic acid, sorbitol, itaconic acid, and 2,5-furan dicarboxylic acid, which have not been produced by E. coli until now. (orig.)

Enzymes in Fermented Fish.

Science.gov (United States)

Giyatmi; Irianto, H E

Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

Probiotic fermented dairy products

OpenAIRE

Adnan Tamime; Rajka Božanić; Irena Rogelj

2003-01-01

Fermented dairy products are the most popular vehicle used in theindustry for the implantation of the probiotic microflora in humans. Therefore this paper provides an overview of new knowledge on probiotic fermented dairy products. It involves historical developments, commercial probiotic microorganisms and products, and their therapeutic properties, possibilities of quality improvement of different types of newly developed fermented dairy products together with fermented goat’s milk products.

Ethanol Production by Soy Fiber Treatment and Simultaneous Saccharification and Co-Fermentation in an Integrated Corn-Soy Biorefinery

Directory of Open Access Journals (Sweden)

Jasreen K. Sekhon

2018-05-01

Full Text Available Insoluble fiber (IF recovered from the enzyme-assisted aqueous extraction process (EAEP of soybeans is a fraction rich in carbohydrates and proteins. It can be used to enhance ethanol production in an integrated corn-soy biorefinery, which combines EAEP with traditional corn-based ethanol processing. The present study evaluated IF as a substrate for ethanol production. The effects of treatment of IF (soaking in aqueous ammonia (SAA, liquid hot water (LHW, and enzymatic hydrolysis, primarily simultaneous saccharification and co-fermentation (SSCF, as well as scaling up (250 mL to 60 L on ethanol production from IF alone or a corn and IF slurry were investigated. Enzymatic hydrolysis (pectinase, cellulase, and xylanase, each added at 5% soy solids during simultaneous saccharification and fermentation/SSCF was the best treatment to maximize ethanol production from IF. Ethanol yield almost doubled when SSCF of IF was performed with Saccharomyces cerevisiae and Escherichia coli KO11. Addition of IF in dry-grind corn fermentation increased the ethanol production rate (~31%, but low ethanol tolerance of E. coli KO11 was a limiting factor for employing SSCF in combination corn and IF fermentation. Nonlinear Monod modeling accurately predicted the effect of ethanol concentration on E. coli KO11 growth kinetics by Hanes-Woolf linearization. Collectively, the results from this study suggest a potential of IF as a substrate, alone or in dry-grind corn fermentation, where it enhances the ethanol production rate. IF can be incorporated in the current bioethanol industry with no added capital investment, except enzymes.

Diffuse and enteroaggregative patterns of adherence of Escherichia coli isolated from stools of children in northeastern Brazil

Directory of Open Access Journals (Sweden)

Scaletsky Isabel Cristina Affonso

2001-01-01

Full Text Available Childhood diarrheal diseases remain highly endemic in northeastern Brazil. The attributable fraction of all diarrheal diseases among children less than 2 years of age due to Escherichia coli was examined in a 2-year prospective study in two large urban centers of Brazil. Between May 1997 and June 1999, fecal E. coli isolates from 237 children with diarrhea (217 acute and 20 persistent cases and 231 children without diarrhea (controls attending two hospitals in Northeast Brazil were tested for their pattern of adherence to HEp-2 cells and for colony hybridization with DNA probes specific for the six pathotypes of diarrheagenic E. coli. Enteroinvasive E. coli, enterotoxigenic E. coli and enterohemorrhagic E. coli were not isolated from any children. Diffusely adherent E. coli (DAEC and enteroaggregative E. coli (EAEC were the most frequent isolates with similar frequencies from children with or without diarrhea. Atypical EPEC (EAF-negative strains were isolated with similiar frequency from both cases (5.5% and controls (5.6%. Enteropathogenic E. coli (typical EPEC strains, characterized by localized adherence pattern of adherence, hybridization with the EAF probe, and belonging to the classical O serogroups, were significantly associated with diarrhea (P = 0.03. These E. coli strains associated with diarrhea accounted for 9% of all children with diarrhea. Collectively, in Northeast Brazil, E. coli strains comprise a small proportion of severe diarrhea prevalence in children.

Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7

Science.gov (United States)

Kim, Yong-Guy; Lee, Jin-Hyung; Gwon, Giyeon; Kim, Soon-Il; Park, Jae Gyu; Lee, Jintae

2016-01-01

Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC. PMID:27808174

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

Science.gov (United States)

Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

2015-01-01

Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

EFFECT OF FERMENTED CACAO POD SUPPLEMENTATION ON SHEEP RUMEN MICROBIAL FERMENTATION

Directory of Open Access Journals (Sweden)

S. Wulandari

2015-09-01

Full Text Available The objective of this research was to improve beneficial value of cacao pod as sheep feedingredients comprising up to 50% total feed. This research was conducted in two stages. Stage 1 wascacao pod fermentation. Completely randomized design with 3x3 factorial patterns was used in thisstage, in which factor I was microbial inoculum dosage of 0%, 0.05% and 0.1% and factor II wasincubation period of 0, 3 and 6 days. Result demonstrated that six-day fermentation with 0.05%microbial inoculum could lower cacao NDF, ADF and theobromine. The optimum inoculum dosage andfermentation time from stage 1 was applied to stage 2. Stage 2 was rumen microbial fermentation test.This research administrated 3x3 of latin square design. In period I sheep were fed with CF0 (nonfermentedcomplete feed, in period II sheep were given CF 1 (complete feed containing fermentedcacao pod and in period III sheep were given CF2 (fermented complete feed based cacao pod. Resultdemonstrated that pH value of sheep microbial liquid in treatment of CF0, CF1 and CF2 was in normalpH range and did not affect volatile fatty acids (VFA and ammonia. In conclusion, supplementing up to 50% of feed with complete feed containing fermented or non-fermented cacao pod did not affect theprocess of rumen microbial fermentation.

Selection and characterisation of high ethanol tolerant ...

African Journals Online (AJOL)

15% ethanol tolerance. High level ethanol tolerant Saccharomyces yeast, Orc 6, was investigated for its potential application in ethanologenic fermentations. Data presented in this study revealed that Orc 6 yeast isolate tolerated osmotic stress above 12% (w/v) sorbitol and 15% (w/v) sucrose equivalent of osmotic pressure ...

Fermentation performance optimization in an ectopic fermentation system.

Science.gov (United States)

Yang, Xiaotong; Geng, Bing; Zhu, Changxiong; Li, Hongna; He, Buwei; Guo, Hui

2018-07-01

Ectopic fermentation systems (EFSs) were developed for wastewater treatment. Previous studies have investigated the ability of thermophilic bacteria to improve fermentation performance in EFS. Continuing this research, we evaluated EFS performance using principle component analysis and investigated the addition of different proportions of cow dung. Viable bacteria communities were clustered and identified using BOX-AIR-based repetitive extragenic palindromic-PCR and 16S rDNA analysis. The results revealed optimal conditions for the padding were maize straw inoculated with thermophilic bacteria. Adding 20% cow dung yielded the best pH values (6.94-8.56), higher temperatures, increased wastewater absorption, improved litter quality, and greater microbial quantities. The viable bacteria groups were enriched by the addition of thermophilic consortium, and exogenous strains G21, G14, G4-1, and CR-15 were detected in fermentation process. The proportion of Bacillus species in treatment groups reached 70.37% after fermentation, demonstrating that thermophilic bacteria, especially Bacillus, have an important role in EFS, supporting previous predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

The vapour pressure of water as a function of solute concentration above aqueous solutions of fructose, sucrose, raffinose, erythritol, xylitol, and sorbitol

DEFF Research Database (Denmark)

Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter

2002-01-01

The vapour pressure of water above an aqueous solution of sucrose at T = 298.06 K has been measured for 9 sucrose mole fractions up to 0.12. Vapour pressure measurements have also been made on aqueous solutions of meso-erythritol, xylitol, sorbitol, fructose, and raffinose at T = 317.99 K...

Genotypes and phenotypes of Shiga toxin-producing Escherichia coli (STEC in Abeokuta, Southwestern Nigeria

Directory of Open Access Journals (Sweden)

Olowe OA

2014-10-01

Full Text Available Olugbenga Adekunle Olowe,1 Bukola W Aboderin,1,2 Olayinka O Idris,3 Victor O Mabayoje,4 Oluyinka O Opaleye,1 O Catherine Adekunle,1 Rita Ayanbolade Olowe,1 Paul Akinniyi Akinduti,5 Olusola Ojurongbe1 1Department of Medical Microbiology and Parasitology, College of Health Sciences, Osogbo, Osun State, Nigeria; 2Medical Microbiology Unit, Pathology Department, Federal Medical Centre, Abeokuta, Nigeria; 3Department of Microbiology, College of Sciences, Afe Babalola University, Ado Ekiti, Nigeria; 4Department of Haematology, College of Health Sciences, Ladoke Akintola University, Osogbo, Osun State, Nigeria; 5Department of Medical Microbiology and Parasitology, Olabisi Onabanjo University, Ago-Iwoye, Ogun State, Nigeria Purpose: To characterize the prevalence of hemolytic Shiga toxin-producing Escherichia coli (STEC with a multidrug-resistant pattern in different age groups in Abeokuta, Nigeria. Methods: Nonrepetitive E. coli isolates were collected from 202 subjects with or without evidence of diarrhea. Each isolate was biochemically identified and antimicrobial susceptibility testing was performed using the disk diffusion method. A sorbitol fermentation test of all the E. coli isolates was done and the minimum inhibitory concentration of suspected STEC was measured by the standard broth microdilution method to determine antibiotic resistance. The genotypes of stx1, stx2, and hlyA were determined by polymerase chain reaction assay. Results: The majority of subjects were aged ≥40 years (41.6% and were female (61.9%. Of the 202 subjects, 86.1% had STEC isolates (P<0.05. A high rate of STEC isolates resistant to amoxicillin (90.6%, cefotaxime (77.7%, and cefuroxime (75.7% was observed. Resistance to amoxicillin, gentamicin, and cefotaxime was demonstrated with a minimum inhibitory concentration >16 µg/mL in 13.9%, 11.4%, and 10.4% of the isolates, respectively. The prevalence of stx1, stx2, and hlyA was 13.9%, 6.9%, and 2.0%, respectively; 5.5% of

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

Directory of Open Access Journals (Sweden)

Elham Aslankoohi

Full Text Available Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

Diarrhoeagenic Escherichia coli are not a significant cause of diarrhoea in hospitalised children in Kuwait

Directory of Open Access Journals (Sweden)

Pacsa Alexander S

2009-03-01

Full Text Available Abstract Background The importance of diarrhoeagenic Escherichia coli (DEC infections in the Arabian Gulf including Kuwait is not known. The prevalence of DEC (enterotoxigenic [ETEC], enteropathogenic [EPEC], enteroinvasive [EIEC], enterohemorrhagic [EHEC] and enteroaggregative [EAEC] was studied in 537 children ≤ 5 years old hospitalised with acute diarrhoea and 113 matched controls from two hospitals during 2005–07 by PCR assays using E. coli colony pools. Results The prevalence of DEC varied from 0.75% for EHEC to 8.4% for EPEC (mostly atypical variety in diarrhoeal children with no significant differences compared to that in control children (P values 0.15 to 1.00. Twenty-seven EPEC isolates studied mostly belonged to non-traditional serotypes and possessed β and θ intimin subtypes. A total of 54 DEC isolates from diarrhoeal children and 4 from controls studied for antimicrobial susceptibility showed resistance for older antimicrobials, ampicillin (0 to 100%, tetracycline (33 to 100% and trimethoprim (22.2 to 100%; 43.1% of the isolates were multidrug-resistant (resistant to 3 or more agents. Six (10.4% DEC isolates produced extended spectrum β-lactamases and possessed genetic elements (blaCTX-M, blaTEM and ISEcp1 associated with them. Conclusion We speculate that the lack of significant association of DEC with diarrhoea in children in Kuwait compared to countries surrounding the Arabian Gulf Region may be attributable to high environmental and food hygiene due to high disposable income in Kuwait.

Distinct physiological roles for the two L-asparaginase isozymes of Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Srikhanta, Yogitha N. [Department of Microbiology and Immunology, The University of Melbourne, Victoria 3010 (Australia); Atack, John M.; Beacham, Ifor R. [Institute for Glycomics, Griffith University, Gold Coast, QLD 4222 (Australia); Jennings, Michael P., E-mail: m.jennings@griffith.edu.au [Institute for Glycomics, Griffith University, Gold Coast, QLD 4222 (Australia)

2013-07-05

Highlights: •Escherichia coli contains two L-asparaginase isozymes with distinct localization, kinetics and regulation. •Mutant strains were used to examine the roles of these enzymes in L-asparagine utilization. •We report that L-asparaginase II permits growth on asparagine and glycerol under anaerobic conditions. •We propose that this enzyme is the first step in a co-regulated pathway leading to fumarate. •The pathway is regulated by anaerobiosis and cAMP and provides a terminal elector acceptor. -- Abstract: Escherichia coli expresses two L-asparaginase (EC 3.5.1.1) isozymes: L-asparaginse I, which is a low affinity, cytoplasmic enzyme that is expressed constitutively, and L-asparaginase II, a high affinity periplasmic enzyme that is under complex co-transcriptional regulation by both Fnr and Crp. The distinct localisation and regulation of these enzymes suggest different roles. To define these roles, a set of isogenic mutants was constructed that lacked either or both enzymes. Evidence is provided that L-asparaginase II, in contrast to L-asparaginase I, can be used in the provision of an anaerobic electron acceptor when using a non-fermentable carbon source in the presence of excess nitrogen.

A comparative study of glycerol and sorbitol as co-substrates in methanol-induced cultures of Pichia pastoris: temperature effect and scale-up simulation.

Science.gov (United States)

Berrios, Julio; Flores, María-Olga; Díaz-Barrera, Alvaro; Altamirano, Claudia; Martínez, Irene; Cabrera, Zaida

2017-03-01

The production of recombinant proteins by Pichia pastoris under AOX1 promoter is usually performed using methanol together with either glycerol or sorbitol as co-substrate. Although both co-substrates have been widely used, comparative studies are scarce. In addition, these comparisons have been performed at different specific growth rate (µ) that it is well known that has an important effect on productivity. Thus, the effect of using these co-substrates on the production of Rhyzopus oryzae lipase (ROL) by P. pastoris was compared in continuous cultures growing at the same µ at either 22 or 30 °C. Results show that using glycerol as co-substrate led to higher volumetric productivities, and lower specific and volumetric methanol consumption rates. Scale-up simulation with 10-10,000 L bioreactor sizes indicated that glycerol produced the highest volumetric productivity of ROL with lower aeration requirements. Therefore, glycerol rises as a better option than sorbitol in ROL production.

Structure elucidation and quantification of impurities formed between 6-aminocaproic acid and the excipients citric acid and sorbitol in an oral solution using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy

DEFF Research Database (Denmark)

Schou-Pedersen, Anne Marie V; Cornett, Claus; Nyberg, Nils

2015-01-01

Concentrated solutions containing 6-aminocaproic acid and the excipients citric acid and sorbitol have been studied at temperatures of 50 °C, 60 °C, 70 °C and 80 °C as well as at 20 °C. It has previously been reported that the commonly employed citric acid is a reactive excipient, and it is there......Concentrated solutions containing 6-aminocaproic acid and the excipients citric acid and sorbitol have been studied at temperatures of 50 °C, 60 °C, 70 °C and 80 °C as well as at 20 °C. It has previously been reported that the commonly employed citric acid is a reactive excipient...... and cyclized 6-aminocaproic acid, i.e., caprolactam. No reaction products between d-sorbitol and 6-aminocaproic acid could be observed. 3-Hydroxy-3,4-dicarboxy-butanamide-N-hexanoic acid, dimer and caprolactam were also observed after storage at 20 °C for 3 months. The findings imply that an oral solution of 6...

Quantification of viable bacterial starter cultures of Virgibacillus sp. and Tetragenococcus halophilus in fish sauce fermentation by real-time quantitative PCR.

Science.gov (United States)

Udomsil, Natteewan; Chen, Shu; Rodtong, Sureelak; Yongsawatdigul, Jirawat

2016-08-01

Real-time quantitative polymerase chain reaction (qPCR) methods were developed for the quantification of Virgibacillus sp. SK37 and Tetragenococcus halophilus MS33, which were added as starter cultures in fish sauce fermentation. The PCR assays were coupled with propidium monoazide (PMA) treatment of samples to selectively quantify viable cells and integrated with exogenous recombinant Escherichia coli cells to control variabilities in analysis procedures. The qPCR methods showed species-specificity for both Virgibacillus halodenitrificans and T. halophilus as evaluated using 6 reference strains and 28 strains of bacteria isolated from fish sauce fermentation. The qPCR efficiencies were 101.1% for V. halodenitrificans and 90.2% for T. halophilus. The quantification limits of the assays were 10(3) CFU/mL and 10(2) CFU/mL in fish sauce samples with linear correlations over 4 Logs for V. halodenitrificans and T. halophilus, respectively. The matrix effect was not observed when evaluated using fish sauce samples fermented for 1-6 months. The developed PMA-qPCR methods were successfully applied to monitor changes of Virgibacillus sp. SK37 and T. halophilus MS33 in a mackerel fish sauce fermentation model where culture-dependent techniques failed to quantify the starter cultures. The results demonstrated the usability of the methods as practical tools for monitoring the starter cultures in fish sauce fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Screening and characterization of lactic acid bacterial strains that produce fermented milk and reduce cholesterol levels.

Science.gov (United States)

Guan, Xuefang; Xu, Qingxian; Zheng, Yi; Qian, Lei; Lin, Bin

To screen for and characterize lactic acid bacteria strains with the ability to produce fermented milk and reduce cholesterol levels. The strains were isolated from traditional fermented milk in China. In vitro and in vivo evaluation of cholesterol-reduction were used to identify and verify strains of interest. Characteristics were analyzed using spectrophotometry and plate counting assays. The isolate HLX37 consistently produced fermented milk with strong cholesterol-reducing properties was identified as Lactobacillus plantarum (accession number: KR105940) and was thus selected for further study. The cholesterol reduction by strain HLX37 was 45.84%. The isolates were acid-tolerant at pH 2.5 and bile-tolerant at 0.5% (w/v) in simulated gastric juice (pH 2.5) for 2h and in simulated intestinal fluid (pH 8.0) for 3h. The auto-aggregation rate increased to 87.74% after 24h, while the co-aggregation with Escherichia coli DH5 was 27.76%. Strain HLX37 was intrinsically resistant to antibiotics such as penicillin, tobramycin, kanamycin, streptomycin, vancomycin and amikacin. Compared with rats in the model hyperlipidemia group, the total cholesterol content in the serum and the liver as well as the atherogenic index of rats in the viable fermented milk group significantly decreased by 23.33%, 32.37% and 40.23%, respectively. Fewer fat vacuoles and other lesions in liver tissue were present in both the inactivated and viable fermented milk groups compared to the model group. These studies indicate that strain HLX37 of L. plantarum demonstrates probiotic potential, potential for use as a candidate for commercial use for promoting health. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Application of dynamic flux balance analysis to an industrial Escherichia coli fermentation.

Science.gov (United States)

Meadows, Adam L; Karnik, Rahi; Lam, Harry; Forestell, Sean; Snedecor, Brad

2010-03-01

We have developed a reactor-scale model of Escherichia coli metabolism and growth in a 1000 L process for the production of a recombinant therapeutic protein. The model consists of two distinct parts: (1) a dynamic, process specific portion that describes the time evolution of 37 process variables of relevance and (2) a flux balance based, 123-reaction metabolic model of E. coli metabolism. This model combines several previously reported modeling approaches including a growth rate-dependent biomass composition, maximum growth rate objective function, and dynamic flux balancing. In addition, we introduce concentration-dependent boundary conditions of transport fluxes, dynamic maintenance demands, and a state-dependent cellular objective. This formulation was able to describe specific runs with high-fidelity over process conditions including rich media, simultaneous acetate and glucose consumption, glucose minimal media, and phosphate depleted media. Furthermore, the model accurately describes the effect of process perturbations--such as glucose overbatching and insufficient aeration--on growth, metabolism, and titer. (c) 2009 Elsevier Inc. All rights reserved.

A plant-based oral vaccine to protect against systemic intoxication by Shiga toxin type 2

OpenAIRE

Wen, Sharon X.; Teel, Louise D.; Judge, Nicole A.; O’Brien, Alison D.

2006-01-01

Hemolytic uremic syndrome, the leading cause of kidney failure in children, often follows infection with enterohemorrhagic Escherichia coli and is mediated by the Shiga type toxins, particularly type 2 (Stx2), produced by such strains. The challenge in protecting against this life-threatening syndrome is to stimulate an immune response at the site of infection while also protecting against Shiga intoxication at distal sites such as the kidney. As one approach to meeting this challenge, we sou...

Plant innate immunity against human bacterial pathogens

Directory of Open Access Journals (Sweden)

Maeli eMelotto

2014-08-01

Full Text Available Certain human bacterial pathogens such as the enterohemorrhagic Escherichia coli and Salmonella enterica are not proven to be plant pathogens yet. Nonetheless, under certain conditions they can survive on, penetrate into, and colonize internal plant tissues causing serious food borne disease outbreaks. In this review, we highlight current understanding on the molecular mechanisms of plant responses against human bacterial pathogens and discuss salient common and contrasting themes of plant interactions with phytopathogens or human pathogens.

Acid and alcohol tolerance of Escherichia coli O157:H7 in pulque, a typical Mexican beverage.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Díaz-Cruz, Claudio A; Villarruel-López, Angelica; Del Refugio Torres-Vitela, M; Rangel-Vargas, Esmeralda; Castro-Rosas, Javier

2012-03-01

Pulque is a traditional Mexican fermented alcoholic beverage produced from the nectar of maguey agave plants. No data exist on the behavior of Escherichia coli O157:H7 in agave nectar and pulque. An initial trial was done of the behavior of E. coli O157:H7 during fermentation of nectar from a single producer, a nectar mixture from different producers and "seed" pulque. A second trial simulating artisanal pulque production was done by contaminating fresh nectar with a cocktail of three E. coli O157:H7 strains, storing at 16 ° and 22 °C for 14 h, adding seed pulque and fermenting until pulque was formed. A third trial used pulque from the second trial stored at 22 °C as seed to ferment fresh nectar at 22 °C for 48 h (fermentation cycle). This procedure was repeated for an additional two fermentation cycles. During incubation at 16 ° or 22 °C in the first trial, the E. coli O157:H7 strains multiplied in both the single producer nectar and nectar mixture, reaching maximum concentration at 12h. E. coli O157:H7 cell concentration then decreased slowly, although it survived at least 72 h in both fermented nectars. E. coli O157:H7 did not multiply in the seed pulque but did survive at least 72 h. In the second trial, the numbers of E. coli O157:H7 increased approximately 1.5 log CFU/ml at 22 °C and 1.2 log CFU/ml at 16 °C after 14 h. After seed pulque was added, E. coli O157:H7 concentration decreased to approximately 2 log CFU/ml, and then remained constant until pulque was produced. In the third trial, the E. coli O157:H7 cells multiplied and survived during at least three nectar fermentation cycles. The results suggest that E. coli O157:H7 can develop acid and alcohol tolerance in pulque, and constitutes a public health risk for pulque consumers. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation and properties of 1-tetradecanol/1,3:2,4-di-(3,4-dimethyl) benzylidene sorbitol gelatinous form-stable phase change materials

International Nuclear Information System (INIS)

Tian, Tuo; Song, Jian; Niu, Libo; Feng, Rongxiu

2013-01-01

Graphical abstract: The 1,3:2,4-di-(3,4-dimethyl) benzylidene sorbitol can self-assemble to form three-dimensional network and immobilized the 1-tetradecanol. As a result, the gel-to-sol transition temperature of the composite PCM increased and the 1-tetradecanol leakage decreased. Highlights: ► First used of 1,3:2,4-di-(3,4-dimethyl) benzylidene sorbitol in alcohol-based PCMs. ► A new method of doping with exfoliated graphite is presented. ► A possible mechanism for decreasing leakage has been proposed based on SEM results. ► The prepared composite PCMs showed a high-energy storage density. ► The addition of exfoliated graphite enhanced the thermal conductivity of the PCMs. - Abstract: A 1-tetradecanol (TD)/1,3:2,4-di-(3,4-dimethyl) benzylidene sorbitol (DMDBS) composite was prepared as a novel form-stable phase change material (PCM), and the properties of the composites such as the gel-to-sol transition temperature, the latent heat, the microstructure and the thermal storage performance were characterized. The composite was prepared by impregnating DMDBS into TD and the maximum feasible weight percentage of TD was determined to be 94.2 wt%. The gel-to-sol transition temperature of the composite PCM was 158.3–180.0 °C, which is well above the melting point of 1-tetradecanol. Differential scanning calorimeter (DSC) was used to determine the melting and freezing enthalpies of 1-tetradecanol in the composite PCM and the values are 218.5 and 215.3 J g −1 , respectively. Scanning electron microscopy (SEM) results showed that 1-tetradecanol dispersed in the three-dimensional network formed by DMDBS. The relationship between the amount of DMDBS additive and the leakage was also discussed. The thermal conductivity of the composite PCM was improved by doping with exfoliated graphite

Modulation of guanosine nucleotides biosynthetic pathways enhanced GDP-L-fucose production in recombinant Escherichia coli.

Science.gov (United States)

Lee, Won-Heong; Shin, So-Yeon; Kim, Myoung-Dong; Han, Nam Soo; Seo, Jin-Ho

2012-03-01

Guanosine 5'-triphosphate (GTP) is the key substrate for biosynthesis of guanosine 5'-diphosphate (GDP)-L-fucose. In this study, improvement of GDP-L-fucose production was attempted by manipulating the biosynthetic pathway for guanosine nucleotides in recombinant Escherichia coli-producing GDP-L-fucose. The effects of overexpression of inosine 5'-monophosphate (IMP) dehydrogenase, guanosine 5'-monophosphate (GMP) synthetase (GuaB and GuaA), GMP reductase (GuaC) and guanosine-inosine kinase (Gsk) on GDP-L-fucose production were investigated in a series of fed-batch fermentations. Among the enzymes tested, overexpression of Gsk led to a significant improvement of GDP-L-fucose production. Maximum GDP-L-fucose concentration of 305.5 ± 5.3 mg l(-1) was obtained in the pH-stat fed-batch fermentation of recombinant E. coli-overexpressing Gsk, which corresponds to a 58% enhancement in the GDP-L-fucose production compared with the control strain overexpressing GDP-L-fucose biosynthetic enzymes. Such an enhancement of GDP-L-fucose production could be due to the increase in the intracellular level of GMP.

Antimicrobial activity of lactic acid bacteria isolated from bekasam against staphylococcus aureus ATCC 25923, escherichia coli ATCC 25922, and salmonella sp

Science.gov (United States)

Sari, Melia; Suryanto, Dwi; Yurnaliza

2018-03-01

Bekasam is an Indonesian fermented food made of fish. As a fermented food, this food may contain some beneficial bacteria like lactic acid bacteria (LAB), which usually have antimicrobial properties such as organic acid, hydrogen peroxide, and a bacteriocin. A study on antimicrobial activity of LAB isolated from bekasam against some pathogenic bacteria has been conducted. The purpose of this study was to know the ability of crude bacteriocin produced LAB of bekasam against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Salmonella sp. Bekasam sample was taken from South Sumatera. LAB isolation was done using de Man Rogosa and Sharpe agar. A bacterial colony with clear zone was selected and purified to get a single colony. The antagonistic assay of the LAB was conducted in Muller-Hinton agar Selected isolates with higher clearing zone were assayed for antibacterial effect of their crude bacteriocin of different culture incubation time of 6, 9, and 12 hours. The results showed that the crude extract bacteriocin of isolate MS2 of 9 hours culture incubation time inhibited more in Staphylococcus aureus ATCC 25923 with inhibition zone of 13.1 mm, whereas isolate MS9 of 9 hours culture incubation time inhibited more in Escherichia coli ATCC 25922 and Salmonella sp. with inhibition zone of 12.7 and 7.3 mm, respectively.

Fermentation performance of engineered and evolved xylose-fermenting Saccharomyces cerevisiae strains

DEFF Research Database (Denmark)

Sonderegger, M.; Jeppsson, M.; Larsson, C.

2004-01-01

Lignocellulose hydrolysate is an abundant substrate for bioethanol production. The ideal microorganism for such a fermentation process should combine rapid and efficient conversion of the available carbon sources to ethanol with high tolerance to ethanol and to inhibitory components in the hydrol......Lignocellulose hydrolysate is an abundant substrate for bioethanol production. The ideal microorganism for such a fermentation process should combine rapid and efficient conversion of the available carbon sources to ethanol with high tolerance to ethanol and to inhibitory components...... in the hydrolysate. A particular biological problem are the pentoses, which are not naturally metabolized by the main industrial ethanol producer Saccharomyces cerevisiae. Several recombinant, mutated, and evolved xylose fermenting S. cerevisiae strains have been developed recently. We compare here the fermentation...

Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.

Directory of Open Access Journals (Sweden)

Sinjan Choudhary

Full Text Available We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular.

Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.

Science.gov (United States)

Choudhary, Sinjan; Save, Shreyada N; Kishore, Nand; Hosur, Ramakrishna V

2016-01-01

We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular.

Effective Production of Sorbitol and Mannitol from Sugars Catalyzed by Ni Nanoparticles Supported on Aluminium Hydroxide

Directory of Open Access Journals (Sweden)

Rodiansono Rodiansono

2013-06-01

Full Text Available Effective production of hexitols (sorbitol and mannitol was achieved from sugars by means of nickel nanoparticles supported on aluminium hydroxide (NiNPs/AlOH catalyst. NiNPs/AlOH catalyst was prepared by a simple and benign environmentally procedure using less amount of sodium hydroxide. ICP-AES and XRD analyses confirmed that the NiNPs/AlOH catalysts comprised a large amount of remained aluminium hydroxide (i.e. bayerite and gibbsite. The presence of aluminium hydroxide caused a high dispersion Ni metal species. The average Ni crystallite sizes that derived from the Scherrer`s equation for former R-Ni and NiNPs/AlOH were 8.6 nm and 4.1 nm, respectively. The catalyst exhibited high activity and selectivity both hydrogenolysis of disaccharides (sucrose and cellobiose and monosaccharides (glucose, fructose, and xylose at 403 K for 24 h. The NiNPs/AlOH catalyst was found to be reusable for at least five consecutive runs without any significant loss of activity and selectivity. © 2013 BCREC UNDIP. All rights reservedReceived: 21st December 2012; Revised: 7th February 2013; Accepted: 10th February 2013[How to Cite: Rodiansono, R., Shimazu, S. (2013. Effective Production of Sorbitol and Mannitol from Sug-ars Catalyzed by Ni Nanoparticles Supported on Aluminium Hydroxide. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 40-46. (doi:10.9767/bcrec.8.1.4290.40-46][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4290.40-46] | View in  |

Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

Science.gov (United States)

Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

2016-05-01

Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed.

In vitro batch fecal fermentation comparison of gas and short-chain fatty acid production using "slowly fermentable" dietary fibers.

Science.gov (United States)

Kaur, Amandeep; Rose, Devin J; Rumpagaporn, Pinthip; Patterson, John A; Hamaker, Bruce R

2011-01-01

Sustained colonic fermentation supplies beneficial fermentative by-products to the distal colon, which is particularly prone to intestinal ailments. Blunted/delayed initial fermentation may also lead to less bloating. Previously, we reported that starch-entrapped alginate-based microspheres act as a slowly fermenting dietary fiber. This material was used in the present study to provide a benchmark to compare to other "slowly fermentable" fibers. Dietary fibers with previous reports of slow fermentation, namely, long-chain inulin, psyllium, alkali-soluble corn bran arabinoxylan, and long-chain β-glucan, as well as starch-entrapped microspheres were subjected to in vitro upper gastrointestinal digestion and human fecal fermentation and measured over 48 h for pH, gas, and short-chain fatty acids (SCFA). The resistant fraction of cooked and cooled potato starch was used as another form of fermentable starch and fructooligosaccharides (FOS) served as a fast fermenting control. Corn bran arabinoxylan and long-chain β-glucan initially appeared slower fermenting with comparatively low gas and SCFA production, but later fermented rapidly with little remaining in the final half of the fermentation period. Long-chain inulin and psyllium had slow and moderate, but incomplete, fermentation. The resistant fraction of cooked and cooled potato starch fermented rapidly and appeared similar to FOS. In conclusion, compared to the benchmark slowly fermentable starch-entrapped microspheres, a number of the purported slowly fermentable fibers fermented fairly rapidly overall and, of this group, only the starch-entrapped microspheres appreciably fermented in the second half of the fermentation period. Consumption of dietary fibers, particularly commercial prebiotics, leads to uncomfortable feelings of bloating and flatulence due to their rapid degradation in our large intestine. This article employs claimed potential slowly fermenting fibers and compares their fermentation rates

Acid-producing capacity from sugars and sugar alcohols among Lactobacillus isolates collected in connection with radiation therapy.

Science.gov (United States)

Almståhl, Annica; Rudbäck, Helena; Basic, Amina; Carlén, Anette; Alstad, Torgny

2017-12-01

To investigate the acid-producing capacity from sugars and sugar alcohols of oral Lactobacillus collected in connection with radiation therapy (RT) to the head and neck region. Lactobacillus were collected from the tongue, buccal mucosa and supragingival plaque in 24 patients before, during, and after RT. The acid-producing capacity of Lactobacillus isolates (n=211) was analyzed using a colorimetric fermentation test in microtiter plates. Solutions containing 2% sugars (sucrose, glucose, fructose, lactose) or sugar-alcohols (sorbitol and xylitol) were used. After 24h of incubation, bacterial acid-producing capacity was determined as strong (pH6). Data regarding intake frequency of sugar-rich products and products with sugar-alcohols was collected. The highest acid-producing capacity using the sugars was seen for isolates collected during RT. Sorbitol was fermented to a higher extent during and post RT, especially among isolates from plaque. Lactobacillus fermenting xylitol showed the highest acid-producing capacity during RT (psugar-rich products or sugar-alcohol containing products and Lactobacillus acid-producing capacity, were found. The results suggest that Lactobacillus isolates, collected from the tongue, buccal mucosa and supragingival plaque, have a higher acid-producing capacity using sugars and sugar-alcohols during RT than one year post RT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pre-harvest management controls and intervention options for reducing escherichia coli O157:H7 shedding in cattle

Science.gov (United States)

Cattle can be naturally colonized with enterohemorrhagic E. coli (EHEC; also known as Shiga Toxin Producing E. coli, STEC) in their gastrointestinal tract. In order to further curtail these human illnesses and ensure a safe and wholesome food supply, research into preharvest E. coli O157:H7 and non...

Relationship between fermentation index and other biochemical changes evaluated during the fermentation of Mexican cocoa (Theobroma cacao) beans.

Science.gov (United States)

Romero-Cortes, Teresa; Salgado-Cervantes, Marco Antonio; García-Alamilla, Pedro; García-Alvarado, Miguel Angel; Rodríguez-Jimenes, Guadalupe del C; Hidalgo-Morales, Madeleine; Robles-Olvera, Víctor

2013-08-15

During traditional cocoa processing, the end of fermentation is empirically determined by the workers; consequently, a high variability on the quality of fermented cocoa beans is observed. Some physicochemical properties (such as fermentation index) have been used to measure the degree of fermentation and changes in quality, but only after the fermentation process has concluded, using dried cocoa beans. This would suggest that it is necessary to establish a relationship between the chemical changes inside the cocoa bean and the fermentation conditions during the fermentation in order to standardize the process. Cocoa beans were traditionally fermented inside wooden boxes, sampled every 24 h and analyzed to evaluate fermentation changes in complete bean, cotyledon and dried beans. The value of the fermentation index suggested as the minimal adequate (≥1) was observed at 72 h in all bean parts analyzed. At this time, values of pH, spectral absorption, total protein hydrolysis and vicilin-class globulins of fermented beans suggested that they were well fermented. Since no difference was found between the types of samples, the pH value could be used as a first indicator of the end of the fermentation and confirmed by evaluation of the fermentation index using undried samples, during the process. © 2013 Society of Chemical Industry.

Metabolic engineering of microbial competitive advantage for industrial fermentation processes.

Science.gov (United States)

Shaw, A Joe; Lam, Felix H; Hamilton, Maureen; Consiglio, Andrew; MacEwen, Kyle; Brevnova, Elena E; Greenhagen, Emily; LaTouf, W Greg; South, Colin R; van Dijken, Hans; Stephanopoulos, Gregory

2016-08-05

Microbial contamination is an obstacle to widespread production of advanced biofuels and chemicals. Current practices such as process sterilization or antibiotic dosage carry excess costs or encourage the development of antibiotic resistance. We engineered Escherichia coli to assimilate melamine, a xenobiotic compound containing nitrogen. After adaptive laboratory evolution to improve pathway efficiency, the engineered strain rapidly outcompeted a control strain when melamine was supplied as the nitrogen source. We additionally engineered the yeasts Saccharomyces cerevisiae and Yarrowia lipolytica to assimilate nitrogen from cyanamide and phosphorus from potassium phosphite, and they outcompeted contaminating strains in several low-cost feedstocks. Supplying essential growth nutrients through xenobiotic or ecologically rare chemicals provides microbial competitive advantage with minimal external risks, given that engineered biocatalysts only have improved fitness within the customized fermentation environment. Copyright © 2016, American Association for the Advancement of Science.

Modelling ethanol production from cellulose: separate hydrolysis and fermentation versus simultaneous saccharification and fermentation

NARCIS (Netherlands)

Drissen, R.E.T.; Maas, R.H.W.; Tramper, J.; Beeftink, H.H.

2009-01-01

In ethanol production from cellulose, enzymatic hydrolysis, and fermentative conversion may be performed sequentially (separate hydrolysis and fermentation, SHF) or in a single reaction vessel (simultaneous saccharification and fermentation, SSF). Opting for either is essentially a trade-off between

Alcoholic fermentation of whey

Energy Technology Data Exchange (ETDEWEB)

Beach, A S; Holland, J W

1958-09-10

The lactose of whey and other milk products is rapidly fermented to ethanol by means of Candida pseudotropicalis strain XI. The fermentation is complete in about 12 hours and yields about 45% ethanol based on the weight of lactose. Conditions favoring the fermentation and inhibiting lactic acid production include pH 4.5, 30/sup 0/, and continuous aeration.

Inactivation of bacterial pathogens in yoba mutandabota, a dairy product fermented with the probiotic Lactobacillus rhamnosus yoba.

Science.gov (United States)

Mpofu, Augustine; Linnemann, Anita R; Nout, Martinus J R; Zwietering, Marcel H; Smid, Eddy J; den Besten, Heidy M W

2016-01-18

Mutandabota is a dairy product consumed as a major source of proteins and micronutrients in Southern Africa. In this study the microbial safety of traditional and a variant of mutandabota fermented with the probiotic Lactobacillus rhamnosus yoba (yoba mutandabota) was investigated by challenging the products with five important food pathogens: Listeria monocytogenes, Salmonella spp., Campylobacter jejuni, Escherichia coli O157:H7 and Bacillus cereus. Pasteurized full-fat cow's milk was used for producing traditional and yoba mutandabota, and was inoculated with a cocktail of strains of the pathogens at an inoculum level of 5.5 log cfu/mL. Survival of the pathogens was monitored over a potential consumption time of 24h for traditional mutandabota, and over 24h of fermentation followed by 24h of potential consumption time for yoba mutandabota. In traditional mutandabota (pH3.4 ± 0.1) no viable cells of B. cereus and C. jejuni were detected 3h after inoculation, while L. monocytogenes, E. coli O157:H7 and Salmonella spp. significantly declined (Pfermentation, mainly due to organic acids produced during fermentation. Only Salmonella spp. was able to grow in yoba mutandabota during the first 9h of fermentation, but then decreased in viable plate count. None of the tested pathogens were detected (>3.5 log inactivation) after 3h into potential consumption time of yoba mutandabota. Inactivation of pathogens in mutandabota is of public health significance because food-borne pathogens endanger public health upon consumption of contaminated food, especially in Southern Africa where there are many vulnerable consumers of mutandabota such as children, elderly and immuno-compromised people with HIV/AIDS. The findings of this study demonstrate that mutandabota fermented with L. rhamnosus yoba has antimicrobial properties against the tested pathogens and it is safer compared to the traditional mutandabota. Copyright © 2015 Elsevier B.V. All rights reserved.

Proteomic View of Interactions of Shiga Toxin-Producing Escherichia coli with the Intestinal Environment in Gnotobiotic Piglets.

Directory of Open Access Journals (Sweden)

Rembert Pieper

Full Text Available Shiga toxin (Stx-producing Escherichia coli cause severe intestinal infections involving colonization of epithelial Peyer's patches and formation of attachment/effacement (A/E lesions. These lesions trigger leukocyte infiltration followed by inflammation and intestinal hemorrhage. Systems biology, which explores the crosstalk of Stx-producing Escherichia coli with the in vivo host environment, may elucidate novel molecular pathogenesis aspects.Enterohemorrhagic E. coli strain 86-24 produces Shiga toxin-2 and belongs to the serotype O157:H7. Bacterial cells were scrapped from stationary phase cultures (the in vitro condition and used to infect gnotobiotic piglets via intestinal lavage. Bacterial cells isolated from the piglets' guts constituted the in vivo condition. Cell lysates were subjected to quantitative 2D gel and shotgun proteomic analyses, revealing metabolic shifts towards anaerobic energy generation, changes in carbon utilization, phosphate and ammonia starvation, and high activity of a glutamate decarboxylase acid resistance system in vivo. Increased abundance of pyridine nucleotide transhydrogenase (PntA and PntB suggested in vivo shortage of intracellular NADPH. Abundance changes of proteins implicated in lipopolysaccharide biosynthesis (LpxC, ArnA, the predicted acyltransferase L7029 and outer membrane (OM assembly (LptD, MlaA, MlaC suggested bacterial cell surface modulation in response to activated host defenses. Indeed, there was evidence for interactions of innate immunity-associated proteins secreted into the intestines (GP340, REG3-γ, resistin, lithostathine, and trefoil factor 3 with the bacterial cell envelope.Proteomic analysis afforded insights into system-wide adaptations of strain 86-24 to a hostile intestinal milieu, including responses to limited nutrients and cofactor supplies, intracellular acidification, and reactive nitrogen and oxygen species-mediated stress. Protein and lipopolysaccharide compositions of the OM

Investigation of Listeria, Salmonella, and toxigenic Escherichia coli in various pet foods.

Science.gov (United States)

Nemser, Sarah M; Doran, Tara; Grabenstein, Michael; McConnell, Terri; McGrath, Timothy; Pamboukian, Ruiqing; Smith, Angele C; Achen, Maya; Danzeisen, Gregory; Kim, Sun; Liu, Yong; Robeson, Sharon; Rosario, Grisel; McWilliams Wilson, Karen; Reimschuessel, Renate

2014-09-01

The Veterinary Laboratory Investigation and Response Network (Vet-LIRN), in collaboration with the Food Emergency Response Network (FERN) and its Microbiology Cooperative Agreement Program (MCAP) laboratories, conducted a study to evaluate the prevalence of selected microbial organisms in various types of pet foods. The goal of this blinded study was to help the Center for Veterinary Medicine prioritize potential future pet food-testing efforts. The study also increased the FERN laboratories' screening capabilities for foodborne pathogens in animal feed matrices, since such pathogens may also be a significant health risk to consumers who come into contact with pet foods. Six U.S. Food and Drug Administration FERN MCAP laboratories analyzed approximately 1056 samples over 2 years. Laboratories tested for Salmonella, Listeria, Escherichia coli O157:H7 enterohemorrhagic E. coli, and Shiga toxin-producing strains of E. coli (STEC). Dry and semimoist dog and cat foods purchased from local stores were tested during Phase 1. Raw dog and cat foods, exotic animal feed, and jerky-type treats purchased through the Internet were tested in Phase 2. Of the 480 dry and semimoist samples, only 2 tested positive: 1 for Salmonella and 1 for Listeria greyii. However, of the 576 samples analyzed during Phase 2, 66 samples were positive for Listeria (32 of those were Listeria monocytogenes) and 15 samples positive for Salmonella. These pathogens were isolated from raw foods and jerky-type treats, not the exotic animal dry feeds. This study showed that raw pet foods may harbor food safety pathogens, such as Listeria monocytogenes and Salmonella. Consumers should handle these products carefully, being mindful of the potential risks to human and animal health.

Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth.

Science.gov (United States)

Martínez, M E; Ranilla, M J; Tejido, M L; Ramos, S; Carro, M D

2010-08-01

Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of forage to concentrate (F:C) ratio and type of forage in the diet on ruminal fermentation and microbial protein synthesis. The purpose of the study was to assess how closely fermenters can mimic the dietary differences found in vivo. The 4 experimental diets contained F:C ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Microbial growth was determined in both systems using (15)N as a microbial marker. Rusitec fermenters detected differences between diets similar to those observed in sheep by changing F:C ratio on pH; neutral detergent fiber digestibility; total volatile fatty acid concentrations; molar proportions of acetate, propionate, butyrate, isovalerate, and caproate; and amylase activity. In contrast, Rusitec fermenters did not reproduce the dietary differences found in sheep for NH(3)-N and lactate concentrations, dry matter (DM) digestibility, proportions of isobutyrate and valerate, carboxymethylcellulase and xylanase activities, and microbial growth and its efficiency. Regarding the effect of the type of forage in the diet, Rusitec fermenters detected differences between diets similar to those found in sheep for most determined parameters, with the exception of pH, DM digestibility, butyrate proportion, and carboxymethylcellulase activity. Minimum pH and maximal volatile fatty acid concentrations were reached at 2h and at 6 to 8h postfeeding in sheep and fermenters, respectively, indicating that feed fermentation was slower in fermenters compared with that in sheep. There were differences between systems in the magnitude of most determined parameters. In general, fermenters showed lower lactate concentrations, neutral detergent fiber digestibility, acetate:propionate ratios, and enzymatic activities. On the contrary, fermenters showed greater NH(3)-N concentrations, DM digestibility, and proportions of propionate

Ethanol production in fermentation of mixed sugars containing xylose

Science.gov (United States)

Viitanen, Paul V [West Chester, PA; Mc Cutchen, Carol M [Wilmington, DE; Li,; Xu, [Newark, DE; Emptage, Mark [Wilmington, DE; Caimi, Perry G [Kennett Square, PA; Zhang, Min [Lakewood, CO; Chou, Yat-Chen [Lakewood, CO; Franden, Mary Ann [Centennial, CO

2009-12-08

Xylose-utilizing Z. mobilis strains were found to have improved ethanol production when grown in medium containing mixed sugars including xylose if sorbitol or mannitol was included in the medium. The effect was seen in concentrations of mixed sugars where no growth lag period occurs, as well as in higher sugars concentrations.

Succinic acid production from xylose mother liquor by recombinant Escherichia coli strain.

Science.gov (United States)

Wang, Honghui; Pan, Jiachuan; Wang, Jing; Wang, Nan; Zhang, Jie; Li, Qiang; Wang, Dan; Zhou, Xiaohua

2014-11-02

Succinic acid (1,4-butanedioic acid) is identified as one of important building-block chemicals. Xylose mother liquor is an abundant industrial residue in xylitol biorefining industry. In this study, xylose mother liquor was utilized to produce succinic acid by recombinant Escherichia coli strain SD121, and the response surface methodology was used to optimize the fermentation media. The optimal conditions of succinic acid fermentation were as follows: 82.62 g L -1 total initial sugars, 42.27 g L -1 MgCO 3 and 17.84 g L -1 yeast extract. The maximum production of succinic acid was 52.09 ± 0.21 g L -1 after 84 h with a yield of 0.63 ± 0.03 g g -1 total sugar, approaching the predicted value (53.18 g L -1 ). It was 1.78-fold of the production of that obtained with the basic medium. This was the first report on succinic acid production from xylose mother liquor by recombinant E. coli strains with media optimization using response surface methodology. This work suggested that the xylose mother liquor could be an alternative substrate for the economical production of succinic acid by recombinant E. coli strains.

Functional effects of Japanese style fermented soy sauce (shoyu) and its components.

Science.gov (United States)

Kataoka, Shigehiro

2005-09-01

The functional effects of Japanese style fermented soy sauce (shoyu) have been studied. Soy sauce promotes digestion, because the consumption of a cup of clear soup containing soy sauce enhances gastric juice secretion in humans. Soy sauce possesses antimicrobial activity against bacteria such as Staphylococcus aureus, Shigella flexneri, Vibrio cholera, Salmonella enteritidis, nonpathogenic Escherichia coli and pathogenic E. coli O157:H7. Soy sauce also contains an antihypertensive component. An angiotensin I-converting enzyme inhibitor having antihypertensive effects was found in soy sauce. The active compound was identified as nicotianamine, which comes from soybeans. Soy sauce exhibits anticarcinogenic effects. Giving diets containing soy sauce to mice inhibit benzo[a]pyrene (BP)-induced forestomach neoplasia. The anticarcinogenic compounds in soy sauce were identified. The flavor components of Japanese style fermented soy sauce, such as 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), which is a characteristic flavor component of Japanese style fermented soy sauce and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 4-hydroxy-5-methyl-3(2H)-furanone (HMF) exhibit antioxidant activities and anticarcinogenic effects on BP-induced mice forestomach neoplasia when fed following carcinogen exposure. The feeding of a diet containing 10% soy sauce to male C3H mice for 13 months also reduces the frequency and multiplicity of spontaneous liver tumors. HDMF and HEMF also exhibit anticataract effects in the spontaneous cataract rat (ICR/f rat). Fermented soy sauce contains three tartaric isoflavone derivatives called shoyuflavones. These shoyuflavones were shown to have inhibitory activities against histidine decarboxylase, which produces histamine, a mediator of inflammation, allergy and gastric acid secretion. Soy sauce also exhibits antiplatelet activity. beta-Carbolines were isolated from soy sauce as the active compounds. Soybeans and wheat, which are the

TRADITIONAL FERMENTED FOODS OF LESOTHO

Directory of Open Access Journals (Sweden)

Tendekayi H. Gadaga

2013-06-01

Full Text Available This paper describes the traditional methods of preparing fermented foods and beverages of Lesotho. Information on the preparation methods was obtained through a combination of literature review and face to face interviews with respondents from Roma in Lesotho. An unstructured questionnaire was used to capture information on the processes, raw materials and utensils used. Four products; motoho (a fermented porridge, Sesotho (a sorghum based alcoholic beverage, hopose (sorghum fermented beer with added hops and mafi (spontaneously fermented milk, were found to be the main fermented foods prepared and consumed at household level in Lesotho. Motoho is a thin gruel, popular as refreshing beverage as well as a weaning food. Sesotho is sorghum based alcoholic beverage prepared for household consumption as well as for sale. It is consumed in the actively fermenting state. Mafi is the name given to spontaneously fermented milk with a thick consistency. Little research has been done on the technological aspects, including the microbiological and biochemical characteristics of fermented foods in Lesotho. Some of the traditional aspects of the preparation methods, such as use of earthenware pots, are being replaced, and modern equipment including plastic utensils are being used. There is need for further systematic studies on the microbiological and biochemical characteristics of these these products.

Fermentation of sugar-beet molasses

Energy Technology Data Exchange (ETDEWEB)

Malchenko, A L; Krishtul, F B

1956-08-25

Sugar-beet molasses is fermented with yeast separated from the mash, sterilized, and reactivated. To reduce sugar losses and hasten fermentation, the yeast is removed from the mash as the cells fall to the bottom during the fermentation process.

Structure and equilibria of Ca 2+-complexes of glucose and sorbitol from multinuclear ( 1H, 13C and 43Ca) NMR measurements supplemented with molecular modelling calculations

Science.gov (United States)

Pallagi, A.; Dudás, Cs.; Csendes, Z.; Forgó, P.; Pálinkó, I.; Sipos, P.

2011-05-01

Ca 2+-complexation of D-glucose and D-sorbitol have been investigated with the aid of multinuclear ( 1H, 13C and 43Ca) NMR spectroscopy and ab initio quantum chemical calculations. Formation constants of the forming 1:1 complexes have been estimated from one-dimensional 13C NMR spectra obtained at constant ionic strength (1 M NaCl). Binding sites were identified from 2D 1H- 43Ca NMR spectra. 2D NMR measurements and ab initio calculations indicated that Ca 2+ ions were bound in a tridentate manner via the glycosidic OH, the ethereal oxygen in the ring and the OH on the terminal carbon for the α- and β-anomers of glucose and for sorbitol simultaneous binding of four hydroxide moieties (C1, C2, C4 and C6) was suggested.

Food Technologies: Fermentation

NARCIS (Netherlands)

Nout, M.J.R.

2014-01-01

Fermentation refers to the use of microorganisms to achieve desirable food properties in the fermented food or beverage. Although the word ‘fermentation’ indicates ‘anaerobic metabolism,’ it is also used in a broader sense to indicate all anaerobic and aerobic microbiological and biochemical

Increased furfural tolerance due to overexpression of NADH-dependent oxidoreductase FucO in Escherichia coli strains engineered for the production of ethanol and lactate.

Science.gov (United States)

Wang, X; Miller, E N; Yomano, L P; Zhang, X; Shanmugam, K T; Ingram, L O

2011-08-01

Furfural is an important fermentation inhibitor in hemicellulose sugar syrups derived from woody biomass. The metabolism of furfural by NADPH-dependent oxidoreductases, such as YqhD (low K(m) for NADPH), is proposed to inhibit the growth and fermentation of xylose in Escherichia coli by competing with biosynthesis for NADPH. The discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural provided a new approach to improve furfural tolerance. Strains that produced ethanol or lactate efficiently as primary products from xylose were developed. These strains included chromosomal mutations in yqhD expression that permitted the fermentation of xylose broths containing up to 10 mM furfural. Expression of fucO from plasmids was shown to increase furfural tolerance by 50% and to permit the fermentation of 15 mM furfural. Product yields with 15 mM furfural were equivalent to those of control strains without added furfural (85% to 90% of the theoretical maximum). These two defined genetic traits can be readily transferred to enteric biocatalysts designed to produce other products. A similar strategy that minimizes the depletion of NADPH pools by native detoxification enzymes may be generally useful for other inhibitory compounds in lignocellulosic sugar streams and with other organisms.

Increased Furfural Tolerance Due to Overexpression of NADH-Dependent Oxidoreductase FucO in Escherichia coli Strains Engineered for the Production of Ethanol and Lactate▿

Science.gov (United States)

Wang, X.; Miller, E. N.; Yomano, L. P.; Zhang, X.; Shanmugam, K. T.; Ingram, L. O.

2011-01-01

Furfural is an important fermentation inhibitor in hemicellulose sugar syrups derived from woody biomass. The metabolism of furfural by NADPH-dependent oxidoreductases, such as YqhD (low Km for NADPH), is proposed to inhibit the growth and fermentation of xylose in Escherichia coli by competing with biosynthesis for NADPH. The discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural provided a new approach to improve furfural tolerance. Strains that produced ethanol or lactate efficiently as primary products from xylose were developed. These strains included chromosomal mutations in yqhD expression that permitted the fermentation of xylose broths containing up to 10 mM furfural. Expression of fucO from plasmids was shown to increase furfural tolerance by 50% and to permit the fermentation of 15 mM furfural. Product yields with 15 mM furfural were equivalent to those of control strains without added furfural (85% to 90% of the theoretical maximum). These two defined genetic traits can be readily transferred to enteric biocatalysts designed to produce other products. A similar strategy that minimizes the depletion of NADPH pools by native detoxification enzymes may be generally useful for other inhibitory compounds in lignocellulosic sugar streams and with other organisms. PMID:21685167

Sugaring-out extraction of acetoin from fermentation broth by coupling with fermentation.

Science.gov (United States)

Dai, Jian-Ying; Ma, Lin-Hui; Wang, Zhuang-Fei; Guan, Wen-Tian; Xiu, Zhi-Long

2017-03-01

Acetoin is a natural flavor and an important bio-based chemical which could be separated from fermentation broth by solvent extraction, salting-out extraction or recovered in the form of derivatives. In this work, a novel method named as sugaring-out extraction coupled with fermentation was tried in the acetoin production by Bacillus subtilis DL01. The effects of six solvents on bacterial growth and the distribution of acetoin and glucose in different solvent-glucose systems were explored. The operation parameters such as standing time, glucose concentration, and volume ratio of ethyl acetate to fermentation broth were determined. In a system composed of fermentation broth, glucose (100%, m/v) and two-fold volume of ethyl acetate, nearly 100% glucose was distributed into bottom phase, and 61.2% acetoin into top phase without coloring matters and organic acids. The top phase was treated by vacuum distillation to remove solvent and purify acetoin, while the bottom phase was used as carbon source to produce acetoin in the next batch of fermentation.

Xylose fermentation to ethanol

Energy Technology Data Exchange (ETDEWEB)

McMillan, J.D.

1993-01-01

The past several years have seen tremendous progress in the understanding of xylose metabolism and in the identification, characterization, and development of strains with improved xylose fermentation characteristics. A survey of the numerous microorganisms capable of directly fermenting xylose to ethanol indicates that wild-type yeast and recombinant bacteria offer the best overall performance in terms of high yield, final ethanol concentration, and volumetric productivity. The best performing bacteria, yeast, and fungi can achieve yields greater than 0.4 g/g and final ethanol concentrations approaching 5%. Productivities remain low for most yeast and particularly for fungi, but volumetric productivities exceeding 1.0 g/L-h have been reported for xylose-fermenting bacteria. In terms of wild-type microorganisms, strains of the yeast Pichia stipitis show the most promise in the short term for direct high-yield fermentation of xylose without byproduct formation. Of the recombinant xylose-fermenting microorganisms developed, recombinant E. coli ATTC 11303 (pLOI297) exhibits the most favorable performance characteristics reported to date.

The Brewing Process: Optimizing the Fermentation

Directory of Open Access Journals (Sweden)

Teodora Coldea

2014-11-01

Full Text Available Beer is a carbonated alcoholic beverage obtained by alcoholic fermentation of malt wort boiled with hops. Brown beer obtained at Beer Pilot Station of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca was the result of a recipe based on blond, caramel and black malt in different proportions, water, hops and yeast. This study aimed to monitorize the evolution of wort in primary and secondary alcoholic fermentation in order to optimize the process. Two wort batches were assambled in order to increase the brewing yeast fermentation performance. The primary fermentation was 14 days, followed by another 14 days of secondary fermentation (maturation. The must fermentation monitoring was done by the automatic FermentoStar analyzer. The whole fermentation process was monitorized (temperature, pH, alcohol concentration, apparent and total wort extract.

Copper-zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

Science.gov (United States)

de Almeida, M. R. H.; Barbano, E. P.; de Carvalho, M. F.; Tulio, P. C.; Carlos, I. A.

2015-04-01

The galvanostatic technique was used to analyze the electrodeposition of Cu-Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu-Zn films were whitish golden, light golden, golden/gray depending on the Cu2+/Zn2+ ratios in the electrodeposition bath, deposition current density (jdep) and charge density (qdep). The highest current efficiency was ∼54.0%, at jdep -1.0 mA cm-2 and qdep 0.40 C cm-2 in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jdep. Also, for same jdep the Cu content increased with qdep. Scanning electron microscopy showed that Cu-Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jdep -20.0 mA cm-2 and qdep 10.0 C cm-2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu-Zn electrodeposits obtained at jdep -8.0, -20.0 and -40.0 mA cm-2, in each case, with qdep 2.0 and 10.0 C cm-2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu-Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes.

27 CFR 24.197 - Production by fermentation.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Production by fermentation... fermentation. In producing special natural wine by fermentation, flavoring materials may be added before or during fermentation. Special natural wine produced by fermentation may be ameliorated in the same manner...

Interfacial enhancement of polypropylene composites modified with sorbitol derivatives and siloxane-silsesquioxane resin

Science.gov (United States)

Dobrzyńska-Mizera, Monika; Dutkiewicz, Michał; Sterzyński, Tomasz; Di Lorenzo, Maria Laura

2015-12-01

Composites based on polypropylene (iPP) modified with a sorbitol derivative (NX8000) and siloxane-silsesquioxane resin (SiOPh) containing maleated polypropylene (MAPP) as compatibilizer were prepared by melt extrusion. Calorimetric investigations were carried out using differential scanning calorimetry (DSC), whereas the morphological and mechanical properties were investigated by scanning electron microscopy (SEM) and static tensile tests. DSC measurements revealed no influence of SiOPh and a slight effect of MAPP addition on the crystallization kinetics of polypropylene. Additionally, the introduction of MAPP into the iPP+NX8000+SiOPh composites increased plastic properties of the samples. All the above was attributed to the compatibilizing effect of MAPP which improved interfacial adhesion between iPP, NX8000 and SiOPh. This phenomenon was also confirmed by the SEM images illustrating more homogenous distribution of the filler in the compatibilized samples.

Protein crowding in solution, frozen and freeze-dried states: small-angle neutron and X-ray scattering study of lysozyme/sorbitol/water systems

Science.gov (United States)

Krueger, Susan; Khodadadi, Sheila; Clark, Nicholas; McAuley, Arnold; Cristiglio, Viviana; Theyencheri, Narayanan; Curtis, Joseph; Shalaev, Evgenyi

2015-03-01

For effective preservation, proteins are often stored as frozen solutions or in glassy states using a freeze-drying process. However, aggregation is often observed after freeze-thaw or reconstitution of freeze-dried powder and the stability of the protein is no longer assured. In this study, small-angle neutron and X-ray scattering (SANS and SAXS) have been used to investigate changes in protein-protein interaction distances of a model protein/cryoprotectant system of lysozyme/sorbitol/water, under representative pharmaceutical processing conditions. The results demonstrate the utility of SAXS and SANS methods to monitor protein crowding at different stages of freezing and drying. The SANS measurements of solution samples showed at least one protein interaction peak corresponding to an interaction distance of ~ 90 Å. In the frozen state, two protein interaction peaks were observed by SANS with corresponding interaction distances at 40 Å as well as 90 Å. On the other hand, both SAXS and SANS data for freeze-dried samples showed three peaks, suggesting interaction distances ranging from ~ 15 Å to 170 Å. Possible interpretations of these interaction peaks will be discussed, as well as the role of sorbitol as a cryoprotectant during the freezing and drying process.

Influence of methanol/sorbitol co-feeding rate on pAOX1 induction in a Pichia pastoris Mut+ strain in bioreactor with limited oxygen transfer rate.

Science.gov (United States)

Carly, F; Niu, H; Delvigne, F; Fickers, P

2016-04-01

High Pichia pastoris biomass density could be obtained using high co-feeding rate of methanol and sorbitol in a fed-batch or continuous culture, while further higher feeding rate finally leads to oxygen limitation in bioreactor. In the literature, there is lack of report about AOX1 promoter regulation with regard to dissolved oxygen level (DO). Therefore, in this work, chemostat cultures were performed to investigate the cell growth, metabolism and regulation of the AOX1 promoter (pAOX1) regarding co-feeding rate of optimized methanol/sorbitol mixture (methanol fraction 0.60 C-mol/C-mol) using a P. pastoris Mut+/pAOX1-lacZ strain. The oxygen transfer rates (OTR) in bioreactor were kept in the range of typical values of large bioreactor, i.e., 4-8 g/(L h) if DO equals 30 % saturation or 5-10 g/(L h) if DO nears zero. For DO >0, an increase of the carbon fed led to an increase of pAOX1 induction. By contrast, when dissolved oxygen was completely depleted, methanol accumulated, causing a 30 % decrease of pAOX1 induction. However, this decrease is more likely to be lined to methanol accumulation than to low level of dissolved oxygen (sorbitol co-feeding allowed cells to adapt to oxygen transient limitations that often occur at industrial scale with reduced effect on pAOX1 induction. The optimal feeding rate tested here was 6.6 mmol C (DCW h)(-1) at an OTR of 8.28 g O2(L h)(-1) with over fivefold pAOX1 induction (probably directly associated with target protein productivity) compared with previous work.

Anaerobic xylose fermentation by Spathaspora passalidarum

DEFF Research Database (Denmark)

Hou, Xiaoru

2012-01-01

A cost-effective conversion of lignocellulosic biomass into bioethanol requires that the xylose released from the hemicellulose fraction (20–40% of biomass) can be fermented. Baker’s yeast, Saccharomyces cerevisiae, efficiently ferments glucose but it lacks the ability to ferment xylose. Xylose-fermenting...... yeast such as Pichia stipitis requires accurately controlled microaerophilic conditions during the xylose fermentation, rendering the process technically difficult and expensive. In this study, it is demonstrated that under anaerobic conditions Spathaspora passalidarum showed high ethanol production...

Fermentation of melon seeds for “Ogiri egusi” as affected by fermentation variables using Bacillus subtilis

Directory of Open Access Journals (Sweden)

Ogueke, C. C.

2013-12-01

Full Text Available Aims: Manipulation of fermentation variables during ‘Ogiri egusi’ production using Bacillus subtilis was studied with the view to improving the fermentation process and quality of product. The variables studied were relative humidity (RH, temperature and pore size of wrapping material. Methodology and results: Effect of variables on amino nitrogen, pH and peroxide value was determined on 24 h basis for 96 h. Attempt on optimization of process using response surface method was made. Amino nitrogen increased with fermentation time, the highest value (6.25 mg N/g being obtained from sample fermented at 75% RH, temperature 35 °C and 90 µm pore size of wrapping material. Fermentation attained its peak at 48 h fermentation time. pH increased into the alkaline range within the period, the highest value (7.81 being from sample that gave the highest amount of amino nitrogen. Peroxide values obtained in all samples were far below the recommended value of 30 Meq/kg. However, the highest value (4.16 Keq/kg was obtained in sample fermented at 85% RH, temperature 30 °C and 70 µm pore size of wrapper. Statistical analysis and response surface plots associated with analysis showed that the quadratic effect of variables was significant (p = 0.05. Effects of relative humidity and pore size of wrapping material were also significant and accounted for 99.56% of the amino nitrogen variation. Conclusion, significance and impact study: Manipulation of the fermentation variables significantly improved the process. Thus use of response surface method optimized the fermentation process especially the effects of relative humidity and pore size of wrapping materials. The suggested combination of variables for optimum fermentation is 75% RH, temperature 35 °C and 70 µm pore size of wrapper. This ultimately will improve product quality and reduce fermentation time.

Fermentative hydrogen production by the new marine Pantoea agglomerans isolated from the mangrove sludge

Energy Technology Data Exchange (ETDEWEB)

Zhu, Daling [College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Wang, Guangce [College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Qiao, Hongjin; Cai, Jinling [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)

2008-11-15

A new fermentative hydrogen-producing bacterium was isolated from mangrove sludge and identified as Pantoea agglomerans using light microscopic examination, biological tests and 16S rRNA gene sequence analysis. The isolated bacterium, designated as P. agglomerans BH-18, is a new strain that has never been optimized as a potential hydrogen-producing bacterium. In this study, the culture conditions and the hydrogen-producing ability of P. agglomerans BH-18 were examined. The strain was a salt-tolerant facultative anaerobe with the initial optimum pH value at 8.0-9.0 and temperature at 30 C on cell growth. During fermentation, hydrogen started to evolve when cell growth entered late-exponential phase and was mainly produced in the stationary phase. The strain was able to produce hydrogen over a wide range of initial pH from 5 to 10, with an optimum initial pH of 6. The level of hydrogen production was affected by the initial glucose concentration, and the optimum value was found to be 10 g glucose/l. The maximum hydrogen-producing yield (2246 ml/l) and overall hydrogen production rate (160 ml/l/h) were obtained at an initial glucose concentration of 10 g/l and an initial pH value of 7.2 in marine culture conditions. In particular, the level of hydrogen production was also affected by the salt concentration. Hydrogen production reached a higher level in fresh culture conditions than in marine ones. In marine conditions, hydrogen productivity was 108 ml/l/h at an initial glucose concentration of 20 g/l and pH value of 7.2, whereas, it increased by 27% in fresh conditions. In addition, this strain could produce hydrogen using glucose and many other carbon sources such as fructose, sucrose, sorbitol and so on. As a result, it is possible that P. agglomerans BH-18 is used for biohydrogen production and biological treatment of mariculture wastewater and marine organic waste. (author)

Fermentative alcohol production

Science.gov (United States)

Wilke, Charles R.; Maiorella, Brian L.; Blanch, Harvey W.; Cysewski, Gerald R.

1982-01-01

An improved fermentation process for producing alcohol which includes the combination of vacuum fermentation and vacuum distillation. Preferably, the vacuum distillation is carried out in two phases, one a fermentor proper operated at atmospheric pressure and a flash phase operated at reduced pressure with recycle of fermentation brew having a reduced alcohol content to the fermentor, using vapor recompression heating of the flash-pot recycle stream to heat the flash-pot or the distillation step, and using "water load balancing" (i.e., the molar ratio of water in the fermentor feed is the same as the molar ratio of water in the distillation overhead).

Commercial Biomass Syngas Fermentation

Directory of Open Access Journals (Sweden)

James Daniell

2012-12-01

Full Text Available The use of gas fermentation for the production of low carbon biofuels such as ethanol or butanol from lignocellulosic biomass is an area currently undergoing intensive research and development, with the first commercial units expected to commence operation in the near future. In this process, biomass is first converted into carbon monoxide (CO and hydrogen (H2-rich synthesis gas (syngas via gasification, and subsequently fermented to hydrocarbons by acetogenic bacteria. Several studies have been performed over the last few years to optimise both biomass gasification and syngas fermentation with significant progress being reported in both areas. While challenges associated with the scale-up and operation of this novel process remain, this strategy offers numerous advantages compared with established fermentation and purely thermochemical approaches to biofuel production in terms of feedstock flexibility and production cost. In recent times, metabolic engineering and synthetic biology techniques have been applied to gas fermenting organisms, paving the way for gases to be used as the feedstock for the commercial production of increasingly energy dense fuels and more valuable chemicals.

Influence of aeration in the fermentative activity of Kloeckera apiculata during fermentation of apple juice

International Nuclear Information System (INIS)

Estela Escalante, Waldir D; Rychtera, Mojmir; Melzoch, Karel; Guerrero Ochoa, Manuel R

2012-01-01

The influence of aeration on the fermentative activity of Kloeckera apiculata RIVE 9-2-1 was studied in order to evaluate the production of metabolites of the fermentation. To achieve this, the strain was cultured in Erlenmeyer flasks containing sterilized and aroma removed apple juice, and the chemical compounds produced during fermentation in shaken (200 min-1) and static (without agitation) cultivation were determined. The results showed that the agitation of the culture medium increases production of higher alcohols (till 591.0 mg/L) compared to static cultivation, whereas on the contrary, the production of acetic acid, ethyl acetate and glycerol (260.0 ± 11.0 mg/L, 196.0 ± 10.0 mg/L y 2.6±0.2 g/L) were higher compared to shaken cultivation (222.0 ± 8.0 mg/L, 96.0 ± 4.5 mg/L and 1.8 ± 0.2 g/L) respectively. Batch cultivations carried out in bioreactor with air flux of 25 l/h reported a growth rate μ of 0.17 h-1, production of ethanol (12.5 ± 2.0 g/L) and other compounds typically produced during alcoholic fermentation. The concentration of dissolved oxygen in the fermentation medium affects its metabolism thus; insufficient amounts of oxygen would provoke a respirofermentative metabolism. The best results in terms of organoleptic quality of the fermented beverage regarding to aroma, taste and flavor was obtained when fermented in static cultivation. The control of aeration during fermentation can be used to control the synthesis of chemical compounds of sensory impact in the production of fermented beverages.

Microbiology and optimization of hydrogen fermentation and bioelectricity production

Energy Technology Data Exchange (ETDEWEB)

Makinen, A.

2013-11-01

yield. Pentose fermentation was accompanied by production of acetate, butyrate and formate, while in hexose fermentation the main soluble end product was lactate. In CSTR Hisarkoy enrichment culture produced H{sub 2} from xylose with the maximum average H{sub 2} yield and production rate of 1.97 mol/mol xylose and 7.3 mmol/h/L, respectively, at suboptimal temperature of 45 deg C for meso- and thermophiles. At 45 deg C microbial community consisted of only two bacterial strains affiliated to Clostridium acetobutylicum and Cirtobacter freundii. An exoeletrogenic culture was enriched on xylose from compost sample in MFCs. In enrichment phase electricity production in MFCs was accompanied with ethanol production. The main bacterium responsible of xylose degradation was xylanolytic Ruminobacillus xylanolyticum and the main bacteria responsible for electricity production were denitrifiers Paracoccus pantotrophus, Comamonas denitrificans and Alicycliphilus denitrificans. Anode potential had a significant effect on current production in MFCs. Compost enrichment culture was able to produce electricity from xylose at poised anode potential of 0.4 V vs standard hydrogen electrode (SHE) having the maximum current density and Coulombic efficiency (CE) of 1.65 A/m{sup 2} and 37 %, respectively. Lower anode potentials of 0.1 or -0.2 V vs SHE didn't lead to current production. Optimum operational parameters for bioelectricity production from xylose by compost enrichment culture were without mixing, external resistance of 100 ohm, 0.5 g/L xylose and pH 7. High current density and CE of 1.74 A/m{sup 2} and 82 %, respectively, were obtained. This is the highest CE obtained with xylose in two-chamber MFC reported in the literature. This very efficient exoelectrogenic culture was dominated by Geobacter species, including G. sulfurreducens, which were enriched on anode biofilm. Xylose fermenters, including Escherichia coli, Sphaerochaeta sp. TQ1, and Bacteroides sp. were present in

Anti-inflammatory properties of fermented soy milk with Lactococcus lactis subsp. lactis S-SU2 in murine macrophage RAW264.7 cells and DSS-induced IBD model mice.

Science.gov (United States)

Kawahara, Miho; Nemoto, Maki; Nakata, Toru; Kondo, Saya; Takahashi, Hajime; Kimura, Bon; Kuda, Takashi

2015-06-01

Six lactic acid bacteria strains (four Lactobacillus plantarum strains and one each of Lactococcus lactis subsp. lactis and Pediococcus pentosaceus) have been isolated and shown to possess anti-oxidant activity. In this study, we determined their acid, bile, salt resistance, and adhesion activity on human enterocyte-like HT-29-Luc and Caco-2 cells. An isolate Lc. lactis S-SU2 showed highest bile resistance and adhesion activity compared to type strains. S-SU2 could ferment both 10% skimmed milk and soy milk while the type strain could not ferment soy milk. Soy milk fermented with S-SU2 showed an increased nitric oxide (NO) secretion in the mouse macrophage RAW264.7 cells without bacterial lipopolysaccharide (LPS). Furthermore, the inhibitory effects of the fermented soy milk on Escherichia coli O111 LPS-induced NO secretion were higher than those of fresh soy milk. Inflammatory bowel disease (IBD) was induced in mice fed either 5% (w/v) dextran sodium sulfate (DSS) in drinking water or 50% soy milk in drinking water. Shortening of colon length, breaking of epithelial cells, lowering liver and thymus weights, and enlargement of spleen are some of the characteristics observed in the IBD, which were prevented by the use of soy milk fermented with Lc. lactis S-SU2. Copyright © 2015 Elsevier B.V. All rights reserved.

Research in fermentation

Energy Technology Data Exchange (ETDEWEB)

Mills, A K

1966-01-01

The following aspects of the biochemistry of fermentation were discussed: carbohydrate, amino acid, S, and phosphate metabolisms in the yeast cell; pantothenic acid and biotin as the essential growth factors in yeast metabolisms; effects of different aeration conditions on yeast growth, mitochondria development, and lipid contents. Gas chromatographic studies of fermentation products are also discussed.

Korean traditional fermented soybean products: Jang

Directory of Open Access Journals (Sweden)

Donghwa Shin

2015-03-01

Fermented products are going beyond the boundaries of their use as mere side dishes, and are seeing significant increases in their use as a functional food. Kanjang (fermented soy sauce, Doenjang (fermented soybean paste, and Gochujang (fermented red pepper paste are the most well-known fermented products in Korea. These products occupy an important place in people's daily lives as seasonings and are used in many side dishes. It has been proven through clinical studies that these products have many health benefits, such as their ability to fight cancer and diabetes, and to prevent obesity and constipation.

Fermented Broth in Tyrosinase- and Melanogenesis Inhibition

OpenAIRE

Chin-Feng Chan; Ching-Cheng Huang; Ming-Yuan Lee; Yung-Sheng Lin

2014-01-01

Fermented broth has a long history of applications in the food, pharmaceutical and cosmetic industries. Recently, the use of fermented broth in skin care products is in ascendance. This review investigates the efficacy of fermented broth in inhibiting tyrosinase and melanogenesis. Possible active ingredients and hypopigmentation mechanisms of fermented broth are discussed, and potential applications of fermented broth in the cosmetic industry are also addressed.

Protein modification by fermentation

DEFF Research Database (Denmark)

Barkholt, Helle Vibeke; Jørgensen, P.B.; Sørensen, Anne Dorthe

1998-01-01

The effect of fermentation on components of potential significance for the allergenicity of pea was analyzed. Pea flour was fermented with three lactic acid bacteria, Pediococcus pentosaceus, Lactococcus raffinolactis, and Lactobacillus plantarum, and two fungi, Rhizopus microsporus, var....... oligosporus and Geotrichum candidum. Residual antigenicity against antipea antibodies was reduced to 10% by the three lactic acid bacteria and R. microsporus. Reactions to anti-pea profilin and anti-Bet v I were still detectable after fermentation. The contents of lectin and pea protease inhibitor were...

In silico genomic analyses reveal three distinct lineages of Escherichia coli O157:H7, one of which is associated with hyper-virulence.

Science.gov (United States)

Laing, Chad R; Buchanan, Cody; Taboada, Eduardo N; Zhang, Yongxiang; Karmali, Mohamed A; Thomas, James E; Gannon, Victor Pj

2009-06-29

Many approaches have been used to study the evolution, population structure and genetic diversity of Escherichia coli O157:H7; however, observations made with different genotyping systems are not easily relatable to each other. Three genetic lineages of E. coli O157:H7 designated I, II and I/II have been identified using octamer-based genome scanning and microarray comparative genomic hybridization (mCGH). Each lineage contains significant phenotypic differences, with lineage I strains being the most commonly associated with human infections. Similarly, a clade of hyper-virulent O157:H7 strains implicated in the 2006 spinach and lettuce outbreaks has been defined using single-nucleotide polymorphism (SNP) typing. In this study an in silico comparison of six different genotyping approaches was performed on 19 E. coli genome sequences from 17 O157:H7 strains and single O145:NM and K12 MG1655 strains to provide an overall picture of diversity of the E. coli O157:H7 population, and to compare genotyping methods for O157:H7 strains. In silico determination of lineage, Shiga-toxin bacteriophage integration site, comparative genomic fingerprint, mCGH profile, novel region distribution profile, SNP type and multi-locus variable number tandem repeat analysis type was performed and a supernetwork based on the combination of these methods was produced. This supernetwork showed three distinct clusters of strains that were O157:H7 lineage-specific, with the SNP-based hyper-virulent clade 8 synonymous with O157:H7 lineage I/II. Lineage I/II/clade 8 strains clustered closest on the supernetwork to E. coli K12 and E. coli O55:H7, O145:NM and sorbitol-fermenting O157 strains. The results of this study highlight the similarities in relationships derived from multi-locus genome sampling methods and suggest a "common genotyping language" may be devised for population genetics and epidemiological studies. Future genotyping methods should provide data that can be stored centrally and

In silico genomic analyses reveal three distinct lineages of Escherichia coli O157:H7, one of which is associated with hyper-virulence

Directory of Open Access Journals (Sweden)