WorldWideScience

Sample records for anaerobic acid resistance

  1. Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xuefei; REN Nanqi

    2007-01-01

    In this study,the two-stage upflow anaerobic sludge blanket(UASB)system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater.The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated.The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor.Apparently,these were not the advisable pH levels that common metha nogenic bacteria could accept.The methanogenic bacteria of the system,viz.Methanosarcina barkeri,had some acid resistance and could still degrade methanol at pH 5.0.If the methanogenic bacteria were trained further,their acid resistance would be improved somewhat.Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5.The performance of granular sludge was attributed to its structure,bacteria species,and the distribution of bacterium inside the granule.

  2. Antimicrobial resistance and susceptibility testing of anaerobic bacteria.

    Science.gov (United States)

    Schuetz, Audrey N

    2014-09-01

    Infections due to anaerobic bacteria can be severe and life-threatening. Susceptibility testing of anaerobes is not frequently performed in laboratories, but such testing is important to direct appropriate therapy. Anaerobic resistance is increasing globally, and resistance trends vary by geographic region. An overview of a variety of susceptibility testing methods for anaerobes is provided, and the advantages and disadvantages of each method are reviewed. Specific clinical situations warranting anaerobic susceptibility testing are discussed.

  3. Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

    Science.gov (United States)

    Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

    2006-01-01

    Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

  4. [Distribution and removal of anaerobic antibiotic resistant bacteria during mesophilic anaerobic digestion of sewage sludge].

    Science.gov (United States)

    Tong, Juan; Wang, Yuan-Yue; Wei Yuan, Song

    2014-10-01

    Sewage sludge is one of the major sources that releasing antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG) into the environment since it contains large amount of ARB, but there is little information about the fate of the anaerobic ARB in the anaerobic digestion of sewage sludge. Therefore, the distribution, removal and seasonal changes of tetracycline and β-lactam antibiotics resistant bacteria in the mesophilic egg-shaped digesters of a municipal wastewater treatment plant were investigated for one year in this study. Results showed that there were higher amounts of ARB and higher resistance rate of β-lactam antibiotics than that of tetracycline antibiotics in the sewage sludge. All ARB could be significantly reduced during the mesophilic anaerobic digestion process by 1.48-1.64 log unit (P < 0.05). Notably, the ampicillin and cephalothin resistance rates were significantly increased after anaerobic digestion by 12.0% and 14.3%, respectively (P < 0.05). The distribution of ARB in the sewage sludge had seasonal change characteristics. Except for chlorotetracycline resistant bacteria, there were more ARB in the sewage sludge in cold season than in warm season (P < 0.05). PMID:25693388

  5. Production of aromatic acids during anaerobic digestion of citrus peel

    Energy Technology Data Exchange (ETDEWEB)

    Lane, A.G.

    1980-06-01

    Commercially prepared citrus oils, distilled citrus oils, limonene and the non-volatile fraction of lemon oils were all found to be toxic to the anaerobic digestion process for conversion of citrus waste to methane. Toxicity was characterised by appearance of benzoic, phenylacetic and phenylpropionic acids in the digestion liquors, though these acids were not in themselves toxic. The bulk of the phenylpropionic acid was derived from flavonoids.

  6. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    Volatile fatty acid (VFA) concentration is known as an important indicator to control and optimize anaerobic digestion (AD) process. In this study, an innovative VFA biosensor was developed based on the principle of a microbial desalination cell. The correlation between current densities and VFA...

  7. [Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].

    Science.gov (United States)

    Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang

    2014-04-01

    Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

  8. Anaerobic Biodegradation of Tetrachloroethylene with Acetic Acid as Cometabolism Substrate under Anaerobic Condition

    Institute of Scientific and Technical Information of China (English)

    LI Ye; LIU Fei; CHEN Honghan; SHI Jinhua; WANG Yufan

    2008-01-01

    A series of batch-type experiments with acetate acid as the primary substrate wereperformed using enrichment cultures developed from the anaerobic sludge to investigate the effect ofacetate acid on tetrachloroethylene (PCE) biodegradation. Experimental results indicated that acetateacid was an efficient electron donor in affecting the biotransformability of PCE. Trichloroethylene(TCE) was the primary dehalogenation product, and small amounts of dichloroethylenes (DCEs) werealso detected. No significant further DCEs degradation was detected. PCE degradation rate in theexperiment was 36.6 times faster than background rate in natural groundwater.

  9. Anaerobic conditions improve germination of a gibberellic acid deficient rice

    Science.gov (United States)

    Frantz, Jonathan M.; Bugbee, Bruce

    2002-01-01

    Dwarf plants are useful in research because multiple plants can be grown in a small area. Rice (Oryza sativa L.) is especially important since its relatively simple genome has recently been sequenced. We are characterizing a gibberellic acid (GA) mutant of rice (japonica cv 'Shiokari,' line N-71) that is extremely dwarf (20 cm tall). Unfortunately, this GA mutation is associated with poor germination (70%) under aerobic conditions. Neither exogenous GA nor a dormancy-breaking heat treatment improved germination. However, 95% germination was achieved by germinating the seeds anaerobically, either in a pure N2 environment or submerged in unstirred tap water. The anaerobic conditions appear to break a mild post-harvest dormancy in this rice cultivar. Copyright 2002 Crop Science Society of America.

  10. Triclocarban Influences Antibiotic Resistance and Alters Anaerobic Digester Microbial Community Structure.

    Science.gov (United States)

    Carey, Daniel E; Zitomer, Daniel H; Hristova, Krassimira R; Kappell, Anthony D; McNamara, Patrick J

    2016-01-01

    Triclocarban (TCC) is one of the most abundant organic micropollutants detected in biosolids. Lab-scale anaerobic digesters were amended with TCC at concentrations ranging from the background concentration of seed biosolids (30 mg/kg) to toxic concentrations of 850 mg/kg to determine the effect on methane production, relative abundance of antibiotic resistance genes, and microbial community structure. Additionally, the TCC addition rate was varied to determine the impacts of acclimation time. At environmentally relevant TCC concentrations (max detect = 440 mg/kg), digesters maintained function. Digesters receiving 450 mg/kg of TCC maintained function under gradual TCC addition, but volatile fatty acid concentrations increased, pH decreased, and methane production ceased when immediately fed this concentration. The concentrations of the mexB gene (encoding for a multidrug efflux pump) were higher with all concentrations of TCC compared to a control, but higher TCC concentrations did not correlate with increased mexB abundance. The relative abundance of the gene tet(L) was greater in the digesters that no longer produced methane, and no effect on the relative abundance of the class 1 integron integrase encoding gene (intI1) was observed. Illumina sequencing revealed substantial community shifts in digesters that functionally failed from increased levels of TCC. More subtle, yet significant, community shifts were observed in digesters amended with TCC levels that did not inhibit function. This research demonstrates that TCC can select for a multidrug resistance encoding gene in mixed community anaerobic environments, and this selection occurs at concentrations (30 mg/kg) that can be found in full-scale anaerobic digesters (U.S. median concentration = 22 mg/kg, mean = 39 mg/kg).

  11. Assessment of anaerobic bacterial diversity and its effects on anaerobic system stability and the occurrence of antibiotic resistance genes.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-05-01

    This study evaluated the link between anaerobic bacterial diversity and, the biodegradation of antibiotic combinations and assessed how amending antibiotic combination and increasing concentration of antibiotics in a stepwise fashion influences the development of resistance genes in anaerobic reactors. The biodegradation, sorption and occurrence of the known antibiotic resistance genes (ARGs) of erythromycin and tetracycline were investigated using the processes of UV-HPLC and qPCR analysis respectively. Ion Torrent sequencing was used to detect microbial community changes in response to the addition of antibiotics. The overall results indicated that changes in the structure of a microbial community lead to changes in biodegradation capacity, sorption of antibiotics combinations and occurrence of ARGs. The enhanced biodegradation efficiency appeared to generate variations in the structure of the bacterial community. The results suggested that controlling the ultimate Gram-negative bacterial community, especially Acinetobacter-related populations, may promote the successful biodegradation of antibiotic combinations and reduce the occurrence of ARGs. PMID:26897411

  12. Anaerobic biodegradation of long chain fatty acids : biomethanisation of biomass-associated LCFA as a challenge for the anaerobic treatment of effluents with high lipid/LCFA content

    OpenAIRE

    Pereira, M.A.

    2003-01-01

    Tese de doutoramento em Engenharia Biológica e Química. This work was focused on the anaerobic biodegradation of Long Chain Fatty Acids, especially those that are associated to anaerobic sludge by mechanisms of adsorption, precipitation or entrapment. When continuously fed with oleic acid (EGSB reactors, influent concentrations between 2 and 8 g COD/l and HRT=1 day), suspended and granular anaerobic sludge accumulated palmitic acid. This LCFA was efficiently biomethanised in batch assays, ...

  13. Identification of a conserved protein involved in anaerobic unsaturated fatty acid synthesis in Neiserria gonorrhoeae: implications for facultative and obligate anaerobes that lack FabA

    OpenAIRE

    Isabella, Vincent M.; Clark, Virginia L.

    2011-01-01

    Transcriptome analysis of the facultative anaerobe, Neisseria gonorrhoeae, revealed that many genes of unknown function were induced under anaerobic conditions. Mutation of one such gene, NGO1024, encoding a protein belonging to the 2-nitropropane dioxygenase-like superfamiliy of proteins, was found to result in an inability of gonococci to grow anaerobically. Anaerobic growth of an NG1024 mutant was restored upon supplementation with unsaturated fatty acids (UFA), but not with the saturated ...

  14. Dynamics of the anaerobic process: Effects of volatile fatty acids

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær

    2003-01-01

    both CH4 yield, pH, and gas production and that a unique reaction pattern was seen for the higher VFAs as a result of these pulses. In this study, two thermophilic laboratory reactors were equipped with a novel VFA-sensor for monitoring specific VFAs online. Pulses of VFAs were shown to have a positive......A complex and fast dynamic response of the anaerobic biogas system was observed when the system was subjected to pulses of volatile fatty acids (VFAs). It was shown that a pulse of specific VFAs into a well-functioning continuous stirred tank reactor (CSTR) system operating on cow manure affected...... or inhibition was shown for the degradation of all VFAs tested. Based on the results, it was concluded that measurements of all specific VFAs are important for control purposes and increase and decrease in a specific VFA should always be evaluated in close relationship to the conversion of other VFAs...

  15. Effect of Linear and Non-linear Resistance Exercise on Anaerobic Performance among Young Women

    Directory of Open Access Journals (Sweden)

    Homa Esmaeili

    2015-07-01

    Full Text Available The main goals of strength training are improving muscle strength, power and muscle endurance. The objective of the current study is to compare two popular linear and nonlinear resistance exercises interventions on the anaerobic power.  Previous research has shown differences intervention by the linear and non-linear resistance exercise in performance and strength in male athletes. By the way there are not enough data regarding female subjects. Eighteen young women subjects participated in this study. The subjects were randomly divided in two linear (n=8 and nonlinear (n=10 groups. An 11-week exercise protocol was applied in both groups. The anaerobic power and the body composition variables were measured in the pre and posttests. The results of this research substantiated that there was no difference in the peak anaerobic power between the linear and nonlinear models of the resistance exercise. The results of the current study proved greater improvement in the nonlinear model in contrast to the linear one in two groups at the final phase of the exercise [F(1,16=6.270 , p=0.023]. Greater improvement of the anaerobic power in the undulating group may have been influenced by less overtraining risk in the nonlinear model. The increase of the muscle and lean body mass (LBM directly improved the anaerobic power by increasing the Atp-pc energy system. It was also observed that the nonlinear model of the resistance exercise experienced noticeable improvement in the body composition.  Both linear and non-linear models of resistance exercise improve anaerobic power, but at difference's situation coach and researcher should choose the best method according to type of sport and competition's season.Keywords: Anaerobic power, Energy system, resistance exercise, performance

  16. High rate treatment of terephthalic acid production wastewater in a two-stage anaerobic bioreactor

    NARCIS (Netherlands)

    Kleerebezem, R.; Beckers, J.; Pol, L.W.H.; Lettinga, G.

    2005-01-01

    The feasibility was studied of anaerobic treatment of wastewater generated during purified terephthalic acid (PTA) production in two-stage upflow anaerobic sludge blanket (UASB) reactor system. The artificial influent of the system contained the main organic substrates of PTA-wastewater: acetate, be

  17. Clostridium acetireducens sp nov, a novel amino acid-oxidizing, acetate-reducing anaerobic bacterium

    NARCIS (Netherlands)

    Orlygsson, J; Krooneman, J; Collins, Matthew D.; Pascual, C; Gottschall, JC

    1996-01-01

    Strain 30A(T) (T = type strain), which was isolated from an anaerobic bioreactor fed on waste from a potato starch factory in De Krim, The Netherlands, is a nonmotile, gram-positive, anaerobic, rod-shaped organism that is able to degrade various amino acids, including alanine, leucine, isoleucine, v

  18. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    OpenAIRE

    Samet Azman; Ahmad F. Khadem; Grietje Zeeman; van Lier, Jules B.; Plugge, Caroline M.

    2015-01-01

    Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophili...

  19. Identification of a conserved protein involved in anaerobic unsaturated fatty acid synthesis in Neiserria gonorrhoeae: implications for facultative and obligate anaerobes that lack FabA.

    Science.gov (United States)

    Isabella, Vincent M; Clark, Virginia L

    2011-10-01

    Transcriptome analysis of the facultative anaerobe, Neisseria gonorrhoeae, revealed that many genes of unknown function were induced under anaerobic conditions. Mutation of one such gene, NGO1024, encoding a protein belonging to the 2-nitropropane dioxygenase-like superfamily of proteins, was found to result in an inability of gonococci to grow anaerobically. Anaerobic growth of an NG1024 mutant was restored upon supplementation with unsaturated fatty acids (UFA), but not with the saturated fatty acid palmitate. Gonococcal fatty acid profiles confirmed that NGO1024 was involved in UFA synthesis anaerobically, but not aerobically, demonstrating that gonococci contain two distinct pathways for the production of UFAs, with a yet unidentified aerobic mechanism, and an anaerobic mechanism involving NGO1024. Expression of genes involved in classical anaerobic UFA synthesis, fabA, fabM and fabB, was toxic in gonococci and unable to complement a NGO1024 mutation, suggesting that the chemistry involved in gonococcal anaerobic UFA synthesis is distinct from that of the classical pathway. NGO1024 homologues, which we suggest naming UfaA, form a distinct lineage within the 2-nitropropane dioxygenase-like superfamily, and are found in many facultative and obligate anaerobes that produce UFAs but lack fabA, suggesting that UfaA is part of a widespread pathway involved in UFA synthesis. PMID:21895795

  20. Effect of Linear and Non-linear Resistance Exercise on Anaerobic Performance among Young Women

    OpenAIRE

    Homa Esmaeili; Ali Reza Amani; Taher Afsharnezhad

    2015-01-01

    The main goals of strength training are improving muscle strength, power and muscle endurance. The objective of the current study is to compare two popular linear and nonlinear resistance exercises interventions on the anaerobic power.  Previous research has shown differences intervention by the linear and non-linear resistance exercise in performance and strength in male athletes. By the way there are not enough data regarding female subjects. Eighteen young women subjects participated in th...

  1. Mechanism and controlling strategy of the production and accumulation of propionic acid for anaerobic wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    任南琪; 赵丹; 陈晓蕾; 李建政

    2002-01-01

    The production and accumulation of propionic acid affect significantly anaerobic wastewater treatment system, but the reasons are not approached until now. Based on the results of continuous-flow tests and the analysis of biochemistry and ecology, two mechanisms of producing propionic acid have been put forward. It is demonstrated that the reasons of propionic acid production and accumulation are not caused by higher hydrogen partial pressure. The combination of specific pH value and ORP is the ecological factor affecting propionic acid production, and the equilibrium regulation of NADH/NAD+ ratio in cells is the physiological factor. Meanwhile, it is put forward that using the two-phase anaerobic treatment process and the ethanol type fermentation in anaerobic reactor to avoid propionic acid accumulation are efficient methods.

  2. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  3. Butyric acid from anaerobic fermentation of lignocellulosic biomass hydrolysates by Clostridium sp. strain RPT-4213

    Science.gov (United States)

    A novel Clostridium sp. strain RPT-4213 was found producing butyrate under strict anaerobic conditions. This strain produced 9.47 g L-1 butyric acid from MRS media (0.48 g/g glucose). RPT-4213 was also used to ferment dilute acid pretreated hydrolysates including wheat straw (WSH), corn fiber (CFH...

  4. Influence of lactic acid on the two-phase anaerobic digestion of kitchen wastes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; CAI Wei-min; HE Pin-jing

    2007-01-01

    To evaluate the influence of lactic acid on the methanogenesis, anaerobic digestion of kitchen wastes was firstly conducted in a two-phase anaerobic digestion process, and performance of two digesters fed with lactic acid and glucose was subsequently compared.The results showed that the lactic acid was the main fermentation products of hydrolysis-acidification stage in the two-phase anaerobic digestion process for kitchen wastes. The lactic acid concentration constituted approximately 50% of the chemical oxygen demand (COD) concentration in the hydrolysis-acidification liquid. The maximum organic loading rate was lower in the digester fed with lactic acid than that fed with glucose. Volatile fatty acids (VFAs) and COD removal were deteriorated in the methanogenic reactor fed with to the high concentration of lactic acid fed. It could be concluded that avoiding the presence of the lactic acid is necessary in the hydrolysis-acidification process for the improvement of the two-phase anaerobic digestion process of kitchen wastes.

  5. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment.

    Science.gov (United States)

    Tong, Juan; Liu, Jibao; Zheng, Xiang; Zhang, Junya; Ni, Xiaotang; Chen, Meixue; Wei, Yuansong

    2016-10-01

    The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency. PMID:26970692

  6. In situ volatile fatty acids influence biogas generation from kitchen wastes by anaerobic digestion.

    Science.gov (United States)

    Xu, Zhiyang; Zhao, Mingxing; Miao, Hengfeng; Huang, Zhenxing; Gao, Shumei; Ruan, Wenquan

    2014-07-01

    Anaerobic digestion is considered to be an efficient way of disposing kitchen wastes, which can not only reduce waste amounts, but also produce biogas. However, the excessive accumulation of volatile fatty acids (VFA) caused by high organic loads will inhibit anaerobic digestion intensively. Effects of the VFA composition on biogas generation and microbial community are still required for the investigation under various organic loads of kitchen wastes. Our results showed that the maximum specific methane production was 328.3 ml g TS(-1), and acetic acid was the main inhibitor in methanogenesis. With the increase of organic load, aceticlastic methanogenesis was more sensitive to acetic acid than hydrogenotrophic methanogenesis. Meanwhile, methanogenic microbial community changed significantly, and few species grew well under excessive organic loads. This study provides an attempt to reveal the mechanism of VFA inhibition in anaerobic digestion of kitchen wastes.

  7. Anaerobic oxidation of fatty acids by Clostridium bryantii sp. nov. : a sporeforming, obligately syntrophic bacterium

    OpenAIRE

    Stieb, Marion; Schink, Bernhard

    1985-01-01

    From marine and freshwater mud samples strictly anaerobic, Gram-positive, sporeforming bacteria were isolated which oxidized fatty acids in obligately syntrophic association with H2-utilizing bacteria. Even-numbered fatty acids with up to 10 carbon atoms were degraded to acetate and Hz, odd-numbered fatty acids with up to 11 carbon atoms including 2-methylbutyrate were degraded to acetate, propionate and H2. Neither fumarate, sulfate, thiosulfate, sulfur, nor nitrate were reduced. A marine is...

  8. Preparation of volatile fatty acid (VFA) calcium salts by anaerobic digestion of glucose.

    Science.gov (United States)

    Li, Xiaofen; Swan, Janis E; Nair, Giridhar R; Langdon, Alan G

    2015-01-01

    Many potentially useful intermediates such as hydrogen and volatile fatty acids (VFAs) are formed during the complex anaerobic digestion processes that produce methane from biomass. This study recovers VFAs from an anaerobic digester by a combination of gas stripping and absorption with calcium carbonate slurry. Glucose was used as the model substrate because it is readily available, inexpensive, and easily digested. Sludge from a meatworks anaerobic digester produced methane and carbon dioxide (and sometimes a small amount of hydrogen) when batch-fed with glucose. Conditioning the neutral anaerobic sludge to an acidic pH (below 4.8) was achieved using repeated 1 g L(-1) doses of glucose. After conditioning, mainly VFAs and hydrogen were produced. The intermediate VFAs could be stripped using headspace gas. In subsequent fed-batch digestion/stripping cycles, the pH decreased when glucose was added and then increased when the VFA was gas stripped. The predominant acids formed at low pH values were lactic, butyric, and acetic acids. Lactic acid was converted to VFAs during stripping. The VFA calcium salts recovered were 80% butyrate and 20% acetate with minor quantities of propionate and valerate. PMID:25274086

  9. Energetics and kinetics of anaerobic aromatic and fatty acid degradation

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.

    1992-11-16

    The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, was studied in coculture with Desulfovibrio strain G11. The threshold value for benzoate degradation was dependent on the acetate concentration with benzoate threshold values ranging from 2.4 [mu]M at 20 mM acetate to 30.0 [mu]M at 65 mM acetate. Increasing acetate concentrations also inhibited the rate of benzoate degradation with a apparent K[sub i] for acetate inhibition of 7.0 mM. Lower threshold values were obtained when nitrate rather than sulfate was the terminal electron acceptor. These data are consistent with a thermodynamic explanation for the threshold, and suggest that there is a minimum Gibbs free energy value required for the degradation of benzoate. An acetoacetyl-CoA thiolase has been isolated from Syntrophomonas wolfei; it is apparently a key enzyme controlling the synthesis of poly-B-hydroxyalkanoate from acetyl-CoA in this organism. Kinetic characterization of the acetoacetyl-CoA thiolase from S. wolfei showed that it is similar in its structural, kinetic, and apparent regulatory properties to other biosynthetic acetoacetyl-CoA thiolases from phylogenetically distinct bacteria that synthesize PHA. Intracellular concentrations of CoA and acetyl-CoA are believed to be critical factors regulating the activity of the acetoacetyl-CoA thiolase in S. wolfei. We have also isolated and characterized several new halophilic anaerobic fermentative anaerobes. Phylogenetic analysis indicates that one of these bacteria is a new species in the genus, Haloanaerobium. Two other species appear to be members of the genus, Halobacteroides. Several halophilic acetoclastic methanogenic bacteria have also been isolated and their physiological properties are currently under investigation. We have also isolated an acetate-using dissimilatory iron-reducing bacterium.

  10. Butyric acid from anaerobic fermentation of lignocellulosic biomass hydrolysates by Clostridium tyrobutyricum strain RPT-4213

    Science.gov (United States)

    A newly isolated Clostridium sp. strain RPT-4213 was found to produce butyrate under anaerobic conditions. Fermentations using Lactobacilli MRS Broth produced 9.47 g L-1 butyric acid from glucose (0.48 g/g glucose). However, the strain was not capable of utilizing five carbon sugars. To assess the a...

  11. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  12. Aminomonas paucivorans gen. nov., sp. nov., a mesophilic, anaerobic, amino-acid-utilizing bacterium

    OpenAIRE

    Baena, S.; Fardeau, Marie-Laure; Ollivier, Bernard; Labat, Marc; Thomas, P; Garcia, Jean-Louis; Patel, B.K.C.

    1999-01-01

    A novel, asaccharolytic, amino-acid-degrading bacterium, designated strain GLU-3T, was isolated from an anaerobic lagoon of a dairy wastewater treatment plant. Strain GLU-3T stained Gram-negative and was an obligately anaerobic, non-spore-forming, slightly curved, rod-shaped bacterium (0.3 x 4.0-6.0 micrometers) which existed singly or in pairs. The DNA G+C content was 43 mol%. Optimum growth occurred at 35°C and pH 7.5 on arginine, histidine, threonine and glycine. Acetate was the end-produc...

  13. Mechanism, kinetics and microbiology of inhibition caused by long-chain fatty acids in anaerobic digestion of algal biomass

    OpenAIRE

    Ma, Jingwei; Zhao, Quan-Bao; Laurens, Lieve L. M.; Jarvis, Eric E.; Nagle, Nick J.; Chen, Shulin; Frear, Craig S.

    2015-01-01

    Background Oleaginous microalgae contain a high level of lipids, which can be extracted and converted to biofuel. The lipid-extracted residue can then be further utilized through anaerobic digestion to produce biogas. However, long-chain fatty acids (LCFAs) have been identified as the main inhibitory factor on microbial activity of anaerobic consortium. In this study, the mechanism of LCFA inhibition on anaerobic digestion of whole and lipid-extracted algal biomass was investigated with a ran...

  14. Syntrophomonas zehnderi sp. nov., an anaerobe that degrades long chain fatty acids in co-culture with Methanobacterium formicicum

    NARCIS (Netherlands)

    Sousa, D.Z.; Smidt, H.; Alves, M.M.; Stams, A.J.M.

    2007-01-01

    An anaerobic, mesophilic, syntrophic fatty-acid-oxidizing bacterium, designated strain OL-4T, was isolated as a co-culture with Methanobacterium formicicum DSM 1535NT from an anaerobic expanded granular sludge bed reactor used to treat an oleate-based effluent. Strain OL-4T degraded oleate, a mono-u

  15. Monitoring of volatile fatty acids during anaerobic digestion using a microbial electrochemical sensor

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    resistances were applied, though linear relationships were always observed. Finally, the biosensor was further explored with real AD effluents and the results did not show significant differences with those measured by GC. The simple and efficient biosensor showed promising potential for online, inexpensive...... and reliable measurement of VFA levels during AD and other anaerobic processes. The outcomes will expand the application of bio-electrochemical system application....

  16. Decomposition of Alternative Chirality Amino Acids by Alkaliphilic Anaerobe from Owens Lake, California

    Science.gov (United States)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Hoover, Richard B.

    2009-01-01

    The study of alkaliphilic microbial communities from anaerobic sediments of Owens and Mono Lakes in California led to the isolation of a bacterial strain capable of metabolizing amino acids with alternative chirality. According to the phylogenetic analysis, the anaerobic strain BK1 belongs to the genus Tindallia; however, despite the characteristics of other described species of this genus, the strain BK1 was able to grow on D-arginine and Dlysine. Cell morphology of this strain showed straight, motile, non-spore-forming rods with sizes 0.45 x 1.2-3 microns. Physiological characteristics of the strain showed that it is catalase negative, obligately anaerobic, mesophilic, and obligately alkaliphilic. This isolate is unable to grow at pH 7 and requires CO3 (2-) ions for growth. The strain has chemo-heterotrophic metabolism and is able to ferment various proteolysis products and some sugars. It plays the role of a primary anaerobe within the trophic chain of an anaerobic microbial community by the degradation of complex protein molecules to smaller and less energetic molecules. The new isolate requires NaCl for growth, and can grow within the range of 0.5-13 %, with the optimum at 1 % NaCl (w/v). The temperature range for the growth of the new isolate is 12-40 C with optimum at 35 C. The pH range for the growth of strain BK1 occurs between 7.8 and 11.0 with optimum at 9.5. This paper presents detailed physiological characteristics of the novel isolate from Owens Lake, a unique relic ecosystem of Astrobiological significance, and makes an accent on the ability of this strain to utilize L-amino acids.

  17. Distribution of tetracycline resistance genes in anaerobic treatment of waste sludge: The role of pH in regulating tetracycline resistant bacteria and horizontal gene transfer.

    Science.gov (United States)

    Huang, Haining; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Wan, Rui; Yang, Shouye

    2016-10-01

    Although pH value has been widely regarded as an important factor that affects resource recovery of waste sludge, the potential influence of diverse pHs on the distribution of tetracycline resistance genes (TRGs) during sludge anaerobic treatment is largely unknown. Here we reported that in the range of pH 4-10, 0.58-1.18 log unit increase of target TRGs was observed at pH 4, compared with that at pH 7, while 0.70-1.31 log unit further removal were obtained at pH 10. Mechanism study revealed that varied pHs not only altered the community structures of tetracycline resistant bacteria (TRB), but also changed their relative abundances, benefitting the propagation (acidic pHs) or attenuation (alkaline pHs) of TRB. Further investigation indicated that the amount and gene-possessing abilities of key genetic vectors for horizontal TRGs transfer were greatly promoted at acidic pHs but restricted under alkaline conditions. PMID:27485281

  18. Microbial communities involved in anaerobic degradation of unsaturated or saturated long chain fatty acids

    OpenAIRE

    Sousa, D.Z.; Pereira, M.A.; Stams, A.J.M.; Alves, M. M.; Smidt, H.

    2007-01-01

    Anaerobic long-chain fatty acid (LCFA)-degrading bacteria were identified by combining selective enrichment studies with molecular approaches. Two distinct enrichment cultures growing on unsaturated and saturated LCFAs were obtained by successive transfers in medium containing oleate and palmitate, respectively, as the sole carbon and energy sources. Changes in the microbial composition during enrichment were analyzed by denaturing gradient gel electrophoresis (DGGE) profiling of PCR...

  19. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    Directory of Open Access Journals (Sweden)

    Samet Azman

    2015-03-01

    Full Text Available Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the presence of humic acid. Sodium, potassium, calcium, magnesium and iron salts were tested separately for their efficiency to mitigate humic acid inhibition. All experiments were done under mesophilic conditions (30 °C and at pH 7. Methane production was monitored online, using the Automatic Methane Potential Test System. Methane production, soluble chemical oxygen demand and volatile fatty acid content of the samples were measured to calculate the hydrolysis efficiencies. Addition of magnesium, calcium and iron salts clearly mitigated the inhibitory effects of humic acid and hydrolysis efficiencies reached up to 75%, 65% and 72%, respectively, which were similar to control experiments. Conversely, potassium and sodium salts addition did not mitigate the inhibition and hydrolysis efficiencies were found to be less than 40%. Mitigation of humic acid inhibition via salt addition was also validated by inductively coupled plasma atomic emission spectroscopy analyses, which showed the binding capacity of different cations to humic acid.

  20. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Jin, Xiangdan; Angelidaki, Irini

    2015-01-01

    measured by GC. The simple MDC-based biosensor showed promising potential for online, inexpensive and reliable measurement of VFA levels. The outcomes offer a powerful tool for cost-effective monitoring and optimization of AD process and expand the application of bioelectrochemical system........ Bioelectrochemical systems (e.g. MFC, MDC, MEC et al.) which transfer chemical energy to electricity by degrading organic waste have attracted great interest due to their environmental friendly and sustainability. In this study, to control and optimize AD process, a smart bioelectrochemical system (microbial...... desalination cell, MDC) was built to realize the on-line measuring the concentration of volatile fatty acid (VFA). The correlation between current densities of the biosensor and VFA concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities...

  1. Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid.

    Science.gov (United States)

    Davutluoglu, Orkun I; Seckin, Galip

    2014-01-01

    The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (≈90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover-Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA.

  2. Effects of Dietary Acid Load on Exercise Metabolism and Anaerobic Exercise Performance

    Directory of Open Access Journals (Sweden)

    Susan L. Caciano, Cynthia L. Inman, Elizabeth E. Gockel-Blessing, Edward P. Weiss

    2015-06-01

    Full Text Available Dietary acid load, quantified as the potential renal acid load (PRAL of the diet, affects systemic pH and acid-base regulation. In a previous cross-sectional study, we reported that a low dietary PRAL (i.e. alkaline promoting diet is associated with higher respiratory exchange ratio (RER values during maximal exercise. The purpose of the present study was to confirm the previous findings with a short-term dietary intervention study. Additionally, we sought to determine if changes in PRAL affects submaximal exercise RER (as a reflection of substrate utilization and anaerobic exercise performance. Subjects underwent a graded treadmill exercise test (GXT to exhaustion and an anaerobic exercise performance test on two occasions, once after following a low-PRAL diet and on a separate occasion, after a high-PRAL diet. The diets were continued as long as needed to achieve an alkaline or acid fasted morning urine pH, respectively, with all being 4-9 days in duration. RER was measured during the GXT with indirect calorimetry. The anaerobic performance test was a running time-to-exhaustion test lasting 1-4 min. Maximal exercise RER was lower in the low-PRAL trial compared to the high-PRAL trial (1.10 ± 0.02 vs. 1.20 ± 0.05, p = 0.037. The low-PRAL diet also resulted in a 21% greater time to exhaustion during anaerobic exercise (2.56 ± 0.36 vs. 2.11 ± 0.31 sec, p = 0.044 and a strong tendency for lower RER values during submaximal exercise at 70% VO2max (0.88 ± 0.02 vs. 0.96 ± 0.04, p = 0.060. Contrary to our expectations, a short-term low-PRAL (alkaline promoting diet resulted in lower RER values during maximal-intensity exercise. However, the low-PRAL diet also increased anaerobic exercise time to exhaustion and appears to have shifted submaximal exercise substrate utilization to favor lipid oxidation and spare carbohydrate, both of which would be considered favorable effects in the context of exercise performance.

  3. Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion.

    Science.gov (United States)

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y; Nghiem, L D; Hai, F I; Deng, L J; Wang, J; Wu, Y

    2016-11-01

    The anaerobic digestion process has been primarily utilized for methane containing biogas production over the past few years. However, the digestion process could also be optimized for producing volatile fatty acids (VFAs) and biohydrogen. This is the first review article that combines the optimization approaches for all three possible products from the anaerobic digestion. In this review study, the types and configurations of the bioreactor are discussed for each type of product. This is followed by a review on optimization of common process parameters (e.g. temperature, pH, retention time and organic loading rate) separately for the production of VFA, biohydrogen and methane. This review also includes additional parameters, treatment methods or special additives that wield a significant and positive effect on production rate and these products' yield.

  4. Effects of emulsified octadecanic acids on gas production and cellulolysis by the rumen anaerobic fungus, Piromyces communis M014.

    Science.gov (United States)

    Kim, Chang-H; Lee, Shin J; Ha, Jong K; Kim, Wan Y; Lee, Sung S

    2008-02-01

    Responses of the rumen anaerobic fungus, Piromyces communis M014, to octadecanic long-chain fatty acids (LCFAs) were evaluated by measuring total and hydrogen gas productions, filter paper (FP) cellulose degradation and polysaccharidase enzyme activities. Octadecanic acids (stearic acid, C(18:0); oleic acid, C(18:1); linoleic acid, C(18:2) and linolenic acid, C(18:3)) were emulsified by ultrasonication under anaerobic conditions, and added to the medium at the level of 0.001%. When P. communis M014 was grown in culture with stearic and oleic acids, the cumulative gas production, FP cellulose digestion and enzyme activities were significantly (pinhibited all of the investigated parameters, including cellulose degradation, enzyme activities and gas production, up to 168h incubation. These results indicated that stearic and oleic acids tended to have stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (pinhibition of gas production and cellulase enzyme activity was.

  5. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters

    Science.gov (United States)

    Miller, Jennifer H.; Novak, John T.; Knocke, William R.; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1—a Pseudomonas sp.) and thermophilic (Iso T10—a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457–0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130–0.486, P = 0.075–0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and

  6. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1-a Pseudomonas sp.) and thermophilic (Iso T10-a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457-0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130-0.486, P = 0.075-0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene

  7. Methane Production from Rice Straw Hydrolysate Treated with Dilute Acid by Anaerobic Granular Sludge.

    Science.gov (United States)

    Cheng, Jing-Rong; Liu, Xue-Ming; Chen, Zhi-Yi

    2016-01-01

    The traditional anaerobic digestion process of straw to biogas faces bottlenecks of long anaerobic digestion time, low digestion rate, less gas production, etc., while straw hydrolysate has the potential to overcome these drawbacks. In this study, the dilute sulphuric acid-treated hydrolysate of rice straw (DSARSH) containing high sulfate was firstly proved to be a feasible substrate for methane production under mesophilic digestion by granular sludge within a short digestion time. Batch anaerobic digestion process was operated under different initial chemical oxygen demand (COD) values at temperature of 37 °C with the pH of 8.5. Among the initial COD values ranging from 3000 to 11,000 mg/L, 5000 mg/L was proved to be the most appropriate considering high COD removal efficiency (94.17 ± 1.67 %), CH4 content (65.52 ± 3.12 %), and CH4 yield (0.346 ± 0.008 LCH4/g COD removed) within 120 h. Furthermore, when the studied system operated at the initial COD of 5000 mg/L, the sulfate removal ratio could reach 56.28 %.

  8. Methane Production from Rice Straw Hydrolysate Treated with Dilute Acid by Anaerobic Granular Sludge.

    Science.gov (United States)

    Cheng, Jing-Rong; Liu, Xue-Ming; Chen, Zhi-Yi

    2016-01-01

    The traditional anaerobic digestion process of straw to biogas faces bottlenecks of long anaerobic digestion time, low digestion rate, less gas production, etc., while straw hydrolysate has the potential to overcome these drawbacks. In this study, the dilute sulphuric acid-treated hydrolysate of rice straw (DSARSH) containing high sulfate was firstly proved to be a feasible substrate for methane production under mesophilic digestion by granular sludge within a short digestion time. Batch anaerobic digestion process was operated under different initial chemical oxygen demand (COD) values at temperature of 37 °C with the pH of 8.5. Among the initial COD values ranging from 3000 to 11,000 mg/L, 5000 mg/L was proved to be the most appropriate considering high COD removal efficiency (94.17 ± 1.67 %), CH4 content (65.52 ± 3.12 %), and CH4 yield (0.346 ± 0.008 LCH4/g COD removed) within 120 h. Furthermore, when the studied system operated at the initial COD of 5000 mg/L, the sulfate removal ratio could reach 56.28 %. PMID:26378012

  9. Biodegradability of four phthalic acid esters under anaerobic condition assessed using natural sediment

    Institute of Scientific and Technical Information of China (English)

    Ruttapol Lertsirisopon; Satoshi Soda; Kazunari Sei; Michihiko Ike; Masanori Fujita

    2006-01-01

    Biodegradability of di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP), di-ethylhexyl phthalate (DEHP), and di-isononyl phthalate (DINP) under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters(PAEs)were analyzed by a first-order kinetic model with a lag phase and ranked as DBP>BBP>>DEHP>DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of DINP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.

  10. Effects of dietary Acid load on exercise metabolism and anaerobic exercise performance.

    Science.gov (United States)

    Caciano, Susan L; Inman, Cynthia L; Gockel-Blessing, Elizabeth E; Weiss, Edward P

    2015-06-01

    Dietary acid load, quantified as the potential renal acid load (PRAL) of the diet, affects systemic pH and acid-base regulation. In a previous cross-sectional study, we reported that a low dietary PRAL (i.e. alkaline promoting diet) is associated with higher respiratory exchange ratio (RER) values during maximal exercise. The purpose of the present study was to confirm the previous findings with a short-term dietary intervention study. Additionally, we sought to determine if changes in PRAL affects submaximal exercise RER (as a reflection of substrate utilization) and anaerobic exercise performance. Subjects underwent a graded treadmill exercise test (GXT) to exhaustion and an anaerobic exercise performance test on two occasions, once after following a low-PRAL diet and on a separate occasion, after a high-PRAL diet. The diets were continued as long as needed to achieve an alkaline or acid fasted morning urine pH, respectively, with all being 4-9 days in duration. RER was measured during the GXT with indirect calorimetry. The anaerobic performance test was a running time-to-exhaustion test lasting 1-4 min. Maximal exercise RER was lower in the low-PRAL trial compared to the high-PRAL trial (1.10 ± 0.02 vs. 1.20 ± 0.05, p = 0.037). The low-PRAL diet also resulted in a 21% greater time to exhaustion during anaerobic exercise (2.56 ± 0.36 vs. 2.11 ± 0.31 sec, p = 0.044) and a strong tendency for lower RER values during submaximal exercise at 70% VO2max (0.88 ± 0.02 vs. 0.96 ± 0.04, p = 0.060). Contrary to our expectations, a short-term low-PRAL (alkaline promoting) diet resulted in lower RER values during maximal-intensity exercise. However, the low-PRAL diet also increased anaerobic exercise time to exhaustion and appears to have shifted submaximal exercise substrate utilization to favor lipid oxidation and spare carbohydrate, both of which would be considered favorable effects in the context of exercise performance. Key pointsShort-term (4-9 days) changes in

  11. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Zeikus, J.G.; Jain, M.

    1993-12-31

    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  12. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-01

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

  13. Application of acidic thermal treatment for one- and two-stage anaerobic digestion of sewage sludge.

    Science.gov (United States)

    Takashima, M; Tanaka, Y

    2010-01-01

    The effectiveness of acidic thermal treatment (ATT) was examined in a 106-day continuous experiment, when applied to one- or two-stage anaerobic digestion of sewage sludge (4.3% TS). The ATT was performed at 170 °C and pH 5 for 1 hour (sulfuric acid for lowering pH). The one-stage process was mesophilic at 20 days hydraulic retention time (HRT), and incorporated the ATT as pre-treatment. The two-stage process consisted of a thermophilic digester at 5 days HRT and a mesophilic digester at 15 days HRT, and incorporated the ATT as interstage-treatment. On average, VSS reduction was 48.7% for the one-stage control, 65.8% for the one-stage ATT, 52.7% for the two-stage control and 67.6% for the two-stage ATT. Therefore, VSS reduction was increased by 15-17%, when the ATT was combined in both one- and two-stage processes. In addition, the dewaterability of digested sludge was remarkably improved, and phosphate release was enhanced. On the other hand, total methane production did not differ significantly, and color generation was noted in the digested sludge solutions with the ATT. In conclusion, the anaerobic digestion with ATT can be an attractive alternative for sludge reduction, handling, and phosphorus recovery. PMID:21099053

  14. Sulfate and acid resistant concrete and mortar

    Science.gov (United States)

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

  15. Fatty acid-induced insulin resistance

    DEFF Research Database (Denmark)

    Le Marchand-Brustel, Y; Gual, P; Grémeaux, T;

    2003-01-01

    Insulin resistance, when combined with impaired insulin secretion, contributes to the development of type 2 diabetes. Insulin resistance is characterized by a decrease in the insulin effect on glucose transport in muscle and adipose tissue. Tyrosine phosphorylation of IRS-1 (insulin receptor...... substrate 1) and its binding to PI 3-kinase (phosphoinositide 3-kinase) are critical events in the insulin signalling cascade leading to insulin-stimulated glucose transport. Various studies have implicated lipids as a cause of insulin resistance in muscle. Elevated plasma fatty acid concentrations...... are associated with reduced insulin-stimulated glucose transport activity as a consequence of altered insulin signalling through PI 3-kinase. Modification of IRS-1 by serine phosphorylation could be one of the mechanisms leading to a decrease in IRS-1 tyrosine phosphorylation, PI 3-kinase activity and glucose...

  16. Syntrophic acetate oxidation in two-phase (acid-methane) anaerobic digesters.

    Science.gov (United States)

    Shimada, T; Morgenroth, E; Tandukar, M; Pavlostathis, S G; Smith, A; Raskin, L; Kilian, R E

    2011-01-01

    The microbial processes involved in two-phase anaerobic digestion were investigated by operating a laboratory-scale acid-phase (AP) reactor and analyzing two full-scale, two-phase anaerobic digesters operated under mesophilic (35 °C) conditions. The digesters received a blend of primary sludge and waste activated sludge (WAS). Methane levels of 20% in the laboratory-scale reactor indicated the presence of methanogenic activity in the AP. A phylogenetic analysis of an archaeal 16S rRNA gene clone library of one of the full-scale AP digesters showed that 82% and 5% of the clones were affiliated with the orders Methanobacteriales and Methanosarcinales, respectively. These results indicate that substantial levels of aceticlastic methanogens (order Methanosarcinales) were not maintained at the low solids retention times and acidic conditions (pH 5.2-5.5) of the AP, and that methanogenesis was carried out by hydrogen-utilizing methanogens of the order Methanobacteriales. Approximately 43, 31, and 9% of the archaeal clones from the methanogenic phase (MP) digester were affiliated with the orders Methanosarcinales, Methanomicrobiales, and Methanobacteriales, respectively. A phylogenetic analysis of a bacterial 16S rRNA gene clone library suggested the presence of acetate-oxidizing bacteria (close relatives of Thermacetogenium phaeum, 'Syntrophaceticus schinkii,' and Clostridium ultunense). The high abundance of hydrogen consuming methanogens and the presence of known acetate-oxidizing bacteria suggest that acetate utilization by acetate oxidizing bacteria in syntrophic interaction with hydrogen-utilizing methanogens was an important pathway in the second-stage of the two-phase digestion, which was operated at high ammonium-N concentrations (1.0 and 1.4 g/L). A modified version of the IWA Anaerobic Digestion Model No. 1 (ADM1) with extensions for syntrophic acetate oxidation and weak-acid inhibition adequately described the dynamic profiles of volatile acid production

  17. On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

    Science.gov (United States)

    Colon, Guillermo

    1995-01-01

    The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found

  18. Anaerobic Conversion of Lactic Acid to Acetic Acid and 1,2-Propanediol by Lactobacillus buchneri

    OpenAIRE

    Oude Elferink, S.J.W.H.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S F; FABER, F; Driehuis, F

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lactic acid under anoxic conditions, without requiring an external electron acceptor. Each mole of lactic acid was converted into approximately 0.5 mol of acetic acid, 0.5 mol of 1,2-propanediol, and ...

  19. Enhancement of acidic dye biosorption capacity on poly(ethylenimine) grafted anaerobic granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xue-Fei, E-mail: xfsun06@gmail.com [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Wang, Shu-Guang, E-mail: wsg@sdu.edu.cn [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Cheng, Wen [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Fan, Maohong [School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Tian, Bing-Hui [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Gao, Bao-Yu; Li, Xiao-Ming [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China)

    2011-05-15

    Developing a novel biosorbent with high capacity is crucial to remove dyes from waters in an efficient way. This study demonstrated that porous anaerobic granular sludge could be grafted with polyethylenimine (PEI), which definitely improved the sorption capacity towards Acid Red 18 (AR18) removal. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) study revealed that the PEI modification introduced a large number of amino groups on the surface of sludge, and the amino groups played an important role in the adsorption of dye molecule. Analysis of sorption data using a Boyd plot confirms the film diffusion was the rate-limiting step. The equilibrium data were well fitted Langmuir model, with a maximum AR18 uptake of 520.52 mg/g. Removal of AR18 decreased with the increasing pH and the maximum color removal was observed at pH 2.0. The sorption energy calculated from Dubinin-Radushkevich isotherm was found to be less than 8 for the biosorption of AR 18, which suggested that the biosorption processes of dye molecule onto modified anaerobic granules could be taken place by physical adsorption. Various thermodynamic parameters, such as {Delta}G{sup 0}, {Delta}H{sup 0} and {Delta}S{sup 0}, were also calculated, which indicated that the present system was spontaneous and endothermic process.

  20. The effects of anaerobic training in serum lipids and arachidonic acid metabolites

    Directory of Open Access Journals (Sweden)

    GEORGIOS KIPREOS

    2010-01-01

    Full Text Available Coronary arteries are subjected daily in high shear stress and manifest atherosclerosis very early in life in comparison to other arteries in the human body. Some factors that are implicated in the evolution and progress of this process are the concentration of lipids and arachidonic acid metabolites, such prostacyclin and thromboxane. It has been reported that those who participate in aerobic activities such as walking, cycling, jogging or brisk walking might have normal values of the mentioned chemical substances. On the other hand, it is reported that the effects of anaerobic and strength activities has negative effects on the vascular endothelium, which is essential for the maintenance of hemostatic balance and the local regulation of vascular tone.Therefore, even although extensive research has been conducted in this field, there are crucial gaps in our knowledge. Consequently, the purpose of this brief review is to describe what is known about the effects of anaerobic activities in which the competitive athletes have participated on the following blood parameters: Total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL - C, low density lipoproteins cholesterol (LDL - C, prostacyclin & thromboxane.

  1. Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process.

    Science.gov (United States)

    Zonta, Z; Alves, M M; Flotats, X; Palatsi, J

    2013-03-01

    Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association's Anaerobic Digestion Model N°1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced, providing a plausible explanation of experimental based hypothesis. PMID:23276428

  2. Volatile fatty acids production from anaerobic treatment of cassava waste water: effect of temperature and alkalinity.

    Science.gov (United States)

    Hasan, Salah Din Mahmud; Giongo, Citieli; Fiorese, Mônica Lady; Gomes, Simone Damasceno; Ferrari, Tatiane Caroline; Savoldi, Tarcio Enrico

    2015-01-01

    The production of volatile fatty acids (VFAs), intermediates in the anaerobic degradation process of organic matter from waste water, was evaluated in this work. A batch reactor was used to investigate the effect of temperature, and alkalinity in the production of VFAs, from the fermentation of industrial cassava waste water. Peak production of total volatile fatty acids (TVFAs) was observed in the first two days of acidogenesis. A central composite design was performed, and the highest yield (3400 mg L(-1) of TVFA) was obtained with 30°C and 3 g L(-1) of sodium bicarbonate. The peak of VFA was in 45 h (pH 5.9) with a predominance of acetic (63%) and butyric acid (22%), followed by propionic acid (12%). Decreases in amounts of cyanide (12.9%) and chemical oxygen demand (21.6%) were observed, in addition to the production of biogas (0.53 cm(3) h(-1)). The process was validated experimentally and 3400 g L(-1) of TVFA were obtained with a low relative standard deviation.

  3. Strategies for recovering inhibition caused by long chain fatty acids on anaerobic thermophilic biogas reactors

    DEFF Research Database (Denmark)

    Palatsi, J.; Laureni, M.; Andres, M.V.;

    2009-01-01

    and reducing the bioavailable LCFA concentration, were found to be the best recovery strategies, improving the recovery time from 10 to 2 days, in semi-continuously fed systems. Moreover, acclimatization was introduced by repeated inhibition and process recovery. The subsequent exposure of the anaerobic......Long chain fatty acids (LCFA) concentrations over 1.0 g L1 were inhibiting manure thermophilic digestion, in batch and semi-continuous experiments, resulting in a temporary cease of the biogas production. The aim of the work was to test and evaluate several recovery actions, such as reactor feeding...... patterns, dilution and addition of adsorbents, in order to determine the most appropriate strategy for fast recovery of the reactor activity in manure based plants inhibited by LCFA. Dilution with active inoculum for increasing the biomass/LCFA ratio, or addition of adsorbents for adsorbing the LCFA...

  4. Effect of substrate and cation requirement on anaerobic volatile fatty acid conversion rates at elevated biogas pressure

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Ferrer, I.; Weijma, J.; Lier, van J.B.

    2013-01-01

    This work studied the anaerobic conversion of neutralized volatile fatty acids (VFA) into biogas under Autogenerative High Pressure Digestion (AHPD) conditions. The effects of the operating conditions on the biogas quality, and the substrate utilisation rates were evaluated using 3 AHPD reactors (0.

  5. Activity and viability of methanogens in anaerobic digestion of unsaturated and saturated long-chain fatty acids

    NARCIS (Netherlands)

    Sousa, D.Z.; Salvador, A.F.; Ramos, J.; Guedes, A.P.; Barbosa, S.; Stams, A.J.M.; Alves, M.M.; Pereira, M.A.

    2013-01-01

    Lipids can be anaerobically digested to methane, but methanogens are often considered to be highly sensitive to the long-chain fatty acids (LCFA) deriving from lipids hydrolysis. In this study, the effect of unsaturated (oleate [C18:1]) and saturated (stearate [C18:0] and palmitate [C16:0]) LCFA tow

  6. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water.

  7. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water. PMID:25898079

  8. Characterization of specific membrane fatty acids as chemotaxonomic markers for sulfate-reducing bacteria involved in anaerobic oxidation of methane

    DEFF Research Database (Denmark)

    Elvert, M.; Boetius, A.; Knittel, K.;

    2003-01-01

    and aggregate number in combination with pore water sulfate data provide further evidence of this finding. Using mass balance calculations we present a cell-specific fatty acid pattern most likely displaying a very close resemblance to the still uncultured Desulfosarcina/Desulfococcus species involved in AOM.......Membrane fatty acids were extracted from a sediment core above marine gas hydrates at Hydrate Ridge, NE Pacific. Anaerobic sediments from this environment are characterized by high sulfate reduction rates driven by the anaerobic oxidation of methane (AOM). The assimilation of methane carbon...... into bacterial biomass is indicated by carbon isotope values of specific fatty acids as low as -103parts per thousand. Specific fatty acids released from bacterial membranes include C(16:1omega5c) , C(17:1omega6c) , and cyC(17:0omega5,6) , all of which have been fully characterized by mass spectrometry...

  9. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, March 1992--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    McInerney M.J.

    1995-06-23

    Factors affecting the rate and extent of benzoate degradation by anaerobic syntrophic consortia were studied. Cocultures of a syntrophic benzoate degrader, strain SB, with a hydrogen/formate-using sulfate reducer degraded benzoate to a threshold that depended on the amount of substrate and acetate present. The benzoate threshold was not a function of the inhibition of benzoate degradation capacity by acetate or the toxicity of the undissociated form of acetate. Rather, a critical or minimal Gibb`s free energy value may exist where thermodynamic constraints preclude further benzoate degradation. A sensitive assay to detect low formate concentrations was developed to measure the formate levels when the benzoate threshold was reached. We showed that increased acetate concentrations, even when hydrogen and formate levels are low, affects the extent of benzoate degradation, implicating the importance of interspecies acetate transfer. In addition to benzoate, various saturated and unsaturated fatty acids, 2-methylbutyrate, and methyl esters of fatty acids supported growth in coculture with a hydrogen-using partner. SB is the only syntrophic bacterium known to use both benzoate and fatty acids. Phylogenetic analysis showed that SB clustered with sulfate reducers in the delta subclass of the Proteobacteria. SB grew well in coculture with Desulfoarculus baarsii, a sulfate reducer that uses formate but not hydrogen. This unequivocally shows that SB can grow by interspecies formate transfer.

  10. Synergistic inactivation of anaerobic wastewater biofilm by free nitrous acid and hydrogen peroxide

    International Nuclear Information System (INIS)

    Highlights: ► H2O2 greatly enhances the inactivation of microorganisms in biofilms by FNA. ► About 2-log of inactivation of biofilm microbes was achieved by FNA + H2O2. ► FNA + H2O2 reduced sulfide production and detached biofilm in reactors. -- Abstract: Free nitrous acid (FNA) was recently revealed to be a strong biocide for microbes in anaerobic biofilm, achieving approximately 1-log (90%) inactivation at a concentration of 0.2–0.3 mgHNO2-N/L with an exposure time longer than 6 h. The combined biocidal effects of FNA and hydrogen peroxide (H2O2) on anaerobic wastewater biofilm are investigated in this study. H2O2 greatly enhances the inactivation of microorganisms by FNA. About 2-log (99%) of microbial inactivation was achieved when biofilms were exposed to FNA at 0.2 mgN/L or above and H2O2 at 30 mg/L or above for 6 h or longer. It was found, through response surface methodology and ridge analysis, that FNA is the primary inactivation agent and H2O2 enhances its efficiency. The loss and the subsequent slow recovery of biological activity in biofilm reactors subjected to FNA and H2O2 dosing confirmed that the chemical combination could achieve higher microbial inactivation than with FNA alone. Reaction simulation shows that intermediates of reactions between FNA and H2O2, like peroxynitrite and nitrogen dioxide, would be produced at elevated levels and are likely responsible for the synergism between FNA and H2O2. The combination of FNA and H2O2 could potentially provide an effective solution to sewer biofilm control

  11. Finished leather waste chromium acid extraction and anaerobic biodegradation of the products.

    Science.gov (United States)

    Ferreira, Maria J; Almeida, Manuel F; Pinho, Sílvia C; Santos, Isabel C

    2010-06-01

    Due to the amounts of chromium in the leachate resulting from leather leaching tests, chromium sulfate tanned leather wastes are very often considered hazardous wastes. To overcome this problem, one option could be recovering the chromium and, consequently, lowering its content in the leather scrap. With this objective, chromium leather scrap was leached with sulfuric acid solutions at low temperature also aiming at maximizing chromium removal with minimum attack of the leather matrix. The effects of leather scrap dimension, sulfuric acid and sodium sulfate concentration in the solutions, as well as extraction time and temperature on chromium recovery were studied, and, additionally, organic matrix degradation was evaluated. The best conditions found for chromium recovery were leather scrap conditioning using 25mL of concentrated H(2)SO(4)/L solution at 293 or 313K during 3 or 6days. Under such conditions, 30-60+/-5% of chromium was recovered and as low as 3-6+/-1% of the leather total organic carbon (TOC) was dissolved. Using such treatment, the leather scrap area and volume are reduced and the residue is a more brittle material showing enhanced anaerobic biodegradability. Although good recovery results were achieved, due to the fact that the amount of chromium in eluate exceeded the threshold value this waste was still hazardous. Thus, it needs to be methodically washed in order to remove all the chromium de-linked from collagen.

  12. Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

    Science.gov (United States)

    Liang, Shaobo; McDonald, Armando G; Coats, Erik R

    2015-11-01

    Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. PMID:25708409

  13. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S.F.; Faber, F.; Driehuis, F.

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lac

  14. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion

    Directory of Open Access Journals (Sweden)

    Christopher Neil Lyles

    2014-04-01

    Full Text Available The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11 or a methanogen (M. hungatei. The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  15. Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion.

    Science.gov (United States)

    Lyles, Christopher N; Le, Huynh M; Beasley, William Howard; McInerney, Michael J; Suflita, Joseph M

    2014-01-01

    The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11) or a methanogen (M. hungatei). The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.

  16. Mitigation of Humic Acid Inhibition in Anaerobic Digestion of Cellulose by Addition of Various Salts

    NARCIS (Netherlands)

    Azman, S.; Khadem, A.F.; Zeeman, G.; Van Lier, J.B.; Plugge, C.M.

    2015-01-01

    Humic compounds are inhibitory to the anaerobic hydrolysis of cellulosic biomass. In this study, the impact of salt addition to mitigate the inhibitory effects of humic compounds was investigated. The experiment was conducted using batch tests to monitor the anaerobic hydrolysis of cellulose in the

  17. Chronic exposure to triclosan sustains microbial community shifts and alters antibiotic resistance gene levels in anaerobic digesters.

    Science.gov (United States)

    Carey, Daniel E; Zitomer, Daniel H; Kappell, Anthony D; Choi, Melinda J; Hristova, Krassimira R; McNamara, Patrick J

    2016-08-10

    Triclosan, an antimicrobial chemical found in consumer personal care products, has been shown to stimulate antibiotic resistance in pathogenic bacteria. Although many studies focus on antibiotic resistance pertinent to medical scenarios, resistance developed in natural and engineered environments is less studied and has become an emerging concern for human health. In this study, the impacts of chronic triclosan (TCS) exposure on antibiotic resistance genes (ARGs) and microbial community structure were assessed in lab-scale anaerobic digesters. TCS concentrations from below detection to 2500 mg kg(-1) dry solids were amended into anaerobic digesters over 110 days and acclimated for >3 solid retention time values. Four steady state TCS concentrations were chosen (30-2500 mg kg(-1)). Relative abundance of mexB, a gene coding for a component of a multidrug efflux pump, was significantly higher in all TCS-amended digesters (30 mg kg(-1) or higher) relative to the control. TCS selected for bacteria carrying tet(L) and against those carrying erm(F) at concentrations which inhibited digester function; the pH decrease associated with digester failure was suspected to cause this selection. Little to no impact of TCS was observed on intI1 relative abundance. Microbial communities were also surveyed by high-throughput 16S rRNA gene sequencing. Compared to the control digesters, significant shifts in community structure towards clades containing commensal and pathogenic bacteria were observed in digesters containing TCS. Based on these results, TCS should be included in studies and risk assessments that attempt to elucidate relationships between chemical stressors (e.g. antibiotics), antibiotic resistance genes, and public health. PMID:27291499

  18. Chronic exposure to triclosan sustains microbial community shifts and alters antibiotic resistance gene levels in anaerobic digesters.

    Science.gov (United States)

    Carey, Daniel E; Zitomer, Daniel H; Kappell, Anthony D; Choi, Melinda J; Hristova, Krassimira R; McNamara, Patrick J

    2016-08-10

    Triclosan, an antimicrobial chemical found in consumer personal care products, has been shown to stimulate antibiotic resistance in pathogenic bacteria. Although many studies focus on antibiotic resistance pertinent to medical scenarios, resistance developed in natural and engineered environments is less studied and has become an emerging concern for human health. In this study, the impacts of chronic triclosan (TCS) exposure on antibiotic resistance genes (ARGs) and microbial community structure were assessed in lab-scale anaerobic digesters. TCS concentrations from below detection to 2500 mg kg(-1) dry solids were amended into anaerobic digesters over 110 days and acclimated for >3 solid retention time values. Four steady state TCS concentrations were chosen (30-2500 mg kg(-1)). Relative abundance of mexB, a gene coding for a component of a multidrug efflux pump, was significantly higher in all TCS-amended digesters (30 mg kg(-1) or higher) relative to the control. TCS selected for bacteria carrying tet(L) and against those carrying erm(F) at concentrations which inhibited digester function; the pH decrease associated with digester failure was suspected to cause this selection. Little to no impact of TCS was observed on intI1 relative abundance. Microbial communities were also surveyed by high-throughput 16S rRNA gene sequencing. Compared to the control digesters, significant shifts in community structure towards clades containing commensal and pathogenic bacteria were observed in digesters containing TCS. Based on these results, TCS should be included in studies and risk assessments that attempt to elucidate relationships between chemical stressors (e.g. antibiotics), antibiotic resistance genes, and public health.

  19. Bioelectrochemical reduction of volatile fatty acids in anaerobic digestion effluent for the production of biofuels.

    Science.gov (United States)

    Kondaveeti, Sanath; Min, Booki

    2015-12-15

    This study proves for the first time the feasibility of biofuel production from anaerobic digestion effluent via bioelectrochemical cell operation at various applied cell voltages (1.0, 1.5 and 2.0 V). An increase in cell voltage from 1 to 2 V resulted in more reduction current generation (-0.48 to -0.78 mA) at a lowered cathode potential (-0.45 to -0.84 mV vs Ag/AgCl). Various alcohols were produced depending on applied cell voltages, and the main products were butanol, ethanol, and propanol. Hydrogen and methane production were also observed in the headspace of the cell. A large amount of lactic acid was unexpectedly formed at all conditions, which might be the primary cause of the limited biofuel production. The addition of neutral red (NR) to the system could increase the cathodic reduction current, and thus more biofuels were produced with an enhanced alcohol formation compared to without a mediator.

  20. Sugar and volatile fatty acids dynamic during anaerobic treatment of olive mill wastewater.

    Science.gov (United States)

    Fernandes, L R; Gomes, A C; Lopes, A; Albuquerque, A; Simões, R M

    2016-01-01

    Biogas production has been the main route used to exploit olive mill wastewater (OMW), after pretreatment and/or in combination with other effluents, but more recently the production of chemicals and biopolymers by biotechnological routes has deserved increasing attention by the scientific community. The present paper aims to explore the potential of fresh OMW as a source of volatile fatty acids (VFAs) and biogas. The time profile of VFAs production and the corresponding sugar consumption was followed by high-performance liquid chromatography, in batch anaerobic assays. The experimental results have revealed the very high potential of the OMW for the production of VFAs, mainly due to the high sugar concentration in the effluent (37.8 g/L) and its complete conversion into VFAs, in a time period of 2-3 days. The most abundant VFAs were acetic (48-50%), n-butanoic (12-27%), iso-pentanoic (12-14%) and propanoic (5-13%). The ratio of VFA containing even and odd carbon chains increased with the reduction in the initial chemical oxygen demand concentration of the samples used in the experiments. The conversion of the VFAs to biogas was inhibited at concentrations of 3.5 g/L of VFAs. PMID:26496487

  1. Acetic acid effects on methanogens in the second stage of a two-stage anaerobic system.

    Science.gov (United States)

    Xiao, Keke; Guo, Chenghong; Zhou, Yan; Maspolim, Yogananda; Ng, Wun-Jern

    2016-02-01

    This study reports on biomass tolerance towards high concentrations of acetic acid (HAc) within the system. Biomass from the second stage of a two-stage anaerobic sludge digestion system was used for this study. Microbial community analysis by 454 pyrosequencing highlighted hydrogenotrophic Methanomicrobiales was the predominant archaeal population in the second stage (>99% of the total archaeal community). Second stage biomass degraded HAc up to 4200 mg HAc L(-1) without observable lag phase. However, at HAc-shock loading of 7400 mg HAc L(-1), it showed a one day lag phase associated with decreased biomass activity. After stepwise HAc-acclimation over 27 d, the biomass degraded HAc of up to 8200 mg HAc L(-1) without observable lag phase. The dominance of Methanomicrobiales had remained unchanged in proportion - while the total archaeal population increased during acclimation. This study showed stepwise acclimation could be an approach to accommodate HAc accumulation and hence higher concentrations resulting from an enhanced first stage. PMID:26498097

  2. Fatty Acids Profile during Anaerobic Digestion of Night Soil-Effect of temperature, Calcium Carbonate and Selectively-enriched Inoculum

    OpenAIRE

    S. I. Alam; Singh, L; Maurya, M. S.

    1996-01-01

    Anaerobic biodegradation of night soil was carried out at 5-30 degree centigrade with 1.8-10.62 per cent volatile solids (VS). Biogas production increased with the temperature and VS up to 6.2 per cent. Further increase in VS caused higher Volatile fatty acids (VFA) accumulation resulting in decreased gas production. Acetate and propionate accounted for 62-83 per cent of total VFA. Butyrate to isobutyrate ratio increased with VS. Calcium Carbonate promoted VS degradation, biogas produc...

  3. Anaerobic soil disinfestation and Brassica seed meal amendment alter soil microbiology and system resistance

    Science.gov (United States)

    Brassica seed meal amendments and anaerobic soil disinfestation control a spectrum of soil-borne plant pathogens via a diversity of mechanisms. Transformations in microbial community structure and function in certain instances were determinants of disease control and enhanced plant performance. Fo...

  4. A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The high strength easily biodegradable pollutants(represented by CODE) are strong inhibitors of terephthalic acid(TA) anaerobic biodegradation. At the same time, TA can inhibiteasily biodegradable pollutants removal under anaerobic conditionsto a limited extent. This mutual inhibition could happen and causea low removal efficiency of both TA and CODE, when the effluentfrom TA workshops containing TA and easily biodegradable pollutantsare treated by a single anaerobic reactor system. Based upon thetreatment kinetics analysis of both TA degradation and CODEremoval, a two-stage up-flow anaerobic sludge blanket and up-flowfixed film reactor(UASB-UAFF) system for dealing with this kind ofwastewater was developed and run successfully at laboratory scale.An UASB reactor with the methanogenic consortium as the first stageremoves the easily biodegradable pollutants(CODE). An UAFF reactor as the second stage is mainly in charge of TA degradation. At aHRT 18.5h, the CODE and TA removal rate of the system reached 89.2% and 71.6%, respectively.

  5. Effect of organic loading rate on methane and volatile fatty acids productions from anaerobic treatment of palm oil mill effluent in UASB and UFAF reactors

    OpenAIRE

    Sumate Chaiprapat; Poonsuk Prasertsan; Piyarat Boonsawang; Ronnachai Chaisri

    2007-01-01

    Anaerobic treatment of palm oil mill effluent (POME) with the separation of the acidogenic and methanogenic phase was studied in an up-flow anaerobic sludge blanket (UASB) reactor and an up-flowanaerobic filter (UFAF) reactor. Furthermore, the effect of OLR on methane and volatile fatty acid productions in UASB and UFAF reactors was investigated. In this research, UASB as acidogenic reactor wasused for volatile fatty acid production and UFAF as methanogenic reactor was used for methane produc...

  6. Production of citric acid using its extraction wastewater treated by anaerobic digestion and ion exchange in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-08-01

    In order to solve the problem of extraction wastewater pollution in citric acid industry, an integrated citric acid-methane fermentation process is proposed in this study. Extraction wastewater was treated by mesophilic anaerobic digestion and then used to make mash for the next batch of citric acid fermentation. The recycling process was done for seven batches. Citric acid production (82.4 g/L on average) decreased by 34.1 % in the recycling batches (2nd-7th) compared with the first batch. And the residual reducing sugar exceeded 40 g/L on average in the recycling batches. Pigment substances, acetic acid, ammonium, and metal ions in anaerobic digestion effluent (ADE) were considered to be the inhibitors, and their effects on the fermentation were studied. Results indicated that ammonium, Na(+) and K(+) in the ADE significantly inhibited citric acid fermentation. Therefore, the ADE was treated by acidic cation exchange resin prior to reuse to make mash for citric acid fermentation. The recycling process was performed for ten batches, and citric acid productions in the recycling batches were 126.6 g/L on average, increasing by 1.7 % compared with the first batch. This process could eliminate extraction wastewater discharge and reduce water resource consumption.

  7. Anaerobic waste water treatment: influencing parameters on the acid formation of citric acid production waste - investigation in lab scale and on a large treatment plant

    International Nuclear Information System (INIS)

    Based on the biochemical background of anaerobic waste water treatment processes and on the kinetic criteria the problems of acid formation in one and two stage fermentations are discussed. Chemical analytics play an important role on the control of anaerobic processes. In a separate chapter the significance of different parameters and their application for the control of acidification processes is discussed. Of special importance is an early information on process disturbances and considerations concerning the balancing of the relevant processes. Analytical problems that occur in practice are also dealt with. The practical experience with the large scale wastewater treatment plant, where the described procedures were applied are the main purpose of the thesis. The main influencing parameters on both the lab scale and large scale processes are compared and the influence of important process variables like temperature, pH, load, waste water composition and addition of aerobic and anaerobic sludges on the acid formation is investigated. The results of the work are discussed and compared with results from the literature. In addition a mathematical model dealing with the main pH-dependent equilibrium conditions for acidification reactions was developed on basis of existing models for anaerobic waste water treatment processes. (author)

  8. Resistance development of cystic fibrosis respiratory pathogens when exposed to fosfomycin and tobramycin alone and in combination under aerobic and anaerobic conditions.

    Directory of Open Access Journals (Sweden)

    Gerard McCaughey

    Full Text Available Although antibiotics from different classes are frequently prescribed in combination to prevent the development of resistance amongst Cystic Fibrosis (CF respiratory pathogens, there is a lack of data as to the efficacy of this approach. We have previously shown that a 4:1 (w/w combination of fosfomycin and tobramycin (F:T has excellent activity against CF pathogens with increased activity under physiologically relevant anaerobic conditions. Therefore, the aim of this study was to determine whether F:T could delay or prevent the onset of resistance compared to either fosfomycin or tobramycin alone under aerobic and anaerobic conditions. The frequency of spontaneous mutants arising following exposure to fosfomycin, tobramycin and F:T was determined for clinical Pseudomonas aeruginosa and MRSA isolates under aerobic and anaerobic conditions. The effect of sub-inhibitory concentrations of fosfomycin, tobramycin and F:T on the induction of resistance was also investigated, with the stability of resistance and fitness cost associated with resistance assessed if it developed. P. aeruginosa and MRSA isolates had a lower frequency of spontaneous mutants to F:T compared to fosfomycin and tobramycin under both aerobic and anaerobic conditions. There was a maximum two-fold increase in F:T MICs when P. aeruginosa and MRSA isolates were passaged in sub-inhibitory F:T for 12 days. In contrast, sequential resistance to fosfomycin and tobramycin developed quickly (n = 3 days for both after passage in sub-inhibitory concentrations. Once developed, both fosfomycin and tobramycin resistance was stable and not associated with a biological fitness cost to either P. aeruginosa or MRSA isolates. The results of this study suggest that F:T may prevent the development of resistance compared to fosfomycin or tobramycin alone under aerobic and physiologically relevant anaerobic conditions. F:T may be a potential treatment option in CF patients chronically colonised by MRSA

  9. Comparison of ozone and thermal hydrolysis combined with anaerobic digestion for municipal and pharmaceutical waste sludge with tetracycline resistance genes.

    Science.gov (United States)

    Pei, Jin; Yao, Hong; Wang, Hui; Ren, Jia; Yu, Xiaohua

    2016-08-01

    Biosolids from wastewater treatment plant (WWTP) are environmental reservoirs of antibiotic resistance genes, which attract great concerns on their efficient treatments. Anaerobic digestion (AD) is widely used for sewage sludge treatment but its effectiveness is limited due to the slow hydrolysis. Ozone and thermal hydrolysis pre-treatment were employed to improve AD efficiency and reduce antibiotic-resistant genes in municipal and pharmaceutical waste sludge (MWS and PWS, respectively) in this study. Sludge solubilization achieved 15.75-25.09% and 14.85-33.92% after ozone and thermal hydrolysis, respectively. Both pre-treatments improved cumulative methane production and the enhancements were greater on PWS than MWS. Five tetracycline-resistant genes (tet(A), tet(G), tet(Q), tet(W), tet(X)) and one mobile element (intI1) were qPCR to assess pre-treatments. AD of pre-treated sludge reduced more tet genes than raw sludge for both ozonation and thermal hydrolysis in PWS and MWS. Thermal hydrolysis pre-treatment was more efficient than ozone for reduction after AD. Results of this study help support management options for reducing the spread of antibiotic resistance from biosolids. PMID:27151286

  10. Enhancement of sludge anaerobic biodegradability by combined microwave-H2O2 pretreatment in acidic conditions.

    Science.gov (United States)

    Eswari, Parvathy; Kavitha, S; Kaliappan, S; Yeom, Ick-Tae; Banu, J Rajesh

    2016-07-01

    The aim of this study was to increase the sludge disintegration and reduce the cost of microwave (MW) pretreatment. Thermodynamic analysis of MW hydrolysis revealed the best fit with a first-order kinetic model at a specific energy of 18,600 kJ/kg total solids (TS). Combining H2O2 with MW resulted in a significant increment in solubilization from 30 to 50 % at 18,600 kJ/kg TS. The pH of H2O2-assisted MW-pretreated sludge (MW + H2O2) was in the alkaline range (pH 9-10), and it made the sludge unfavorable for subsequent anaerobic digestion and inhibits methane production. In order to nullify the alkaline effect caused by the MW + H2O2 combination, the addition of acid was considered for pH adjustment. H2O2-assisted MW-pretreated sludge in acidic conditions (MW + H2O2 + acid) showed a maximum methane production of 323 mL/g volatile solids (VS) than others during anaerobic biodegradability. A cost analysis of this study reveals that MW + H2O2 + acid was the most economical method with a net profit of 59.90 €/t of sludge. PMID:27026550

  11. Anaerobes beyond anaerobic digestion

    OpenAIRE

    Sousa, D. Z.; Pereira, M A; Alves, M.M.

    2009-01-01

    Anaerobic microorganisms are widespread in nature. Sediments, gastrointestinal tracks, volcanic vents, geothermal sources are examples of habitats where anaerobic metabolism prevail, in some cases at extreme temperature, pH and pressure conditions. In such microbial ecosystems waste of some is food for others in a true integrated structure. Anaerobic microorganisms are able to use a wide variety of organic and inorganic compounds. Recalcitrant compounds, such as hydrocarbons, a...

  12. Similar PAH fate in anaerobic digesters inoculated with three microbial communities accumulating either volatile fatty acids or methane.

    Directory of Open Access Journals (Sweden)

    Florence Braun

    Full Text Available Urban sludge produced on wastewater treatment plants are often contaminated by organic pollutants such as polycyclic aromatic hydrocarbons (PAH. Their removal under methanogenic conditions was already reported, but the factors influencing this removal remain unclear. Here, we determined the influence of microbial communities on PAH removal under controlled physico-chemical conditions. Twelve mesophilic anaerobic digesters were inoculated with three microbial communities extracted from ecosystems with contrasting pollution histories: a PAH contaminated soil, a PCB contaminated sediment and a low contaminated anaerobic sludge. These anaerobic digesters were operated during 100 days in continuous mode. A sterilised activated sludge, spiked with 13 PAH at concentrations usually encountered in full-scale wastewater treatment plants, was used as substrate. The dry matter and volatile solid degradation, the biogas production rate and composition, the volatile fatty acids (VFA production and the PAH removals were monitored. Bacterial and archaeal communities were compared in abundance (qPCR, in community structure (SSCP fingerprinting and in dominant microbial species (454-pyrosequencing. The bioreactors inoculated with the community extracted from low contaminated anaerobic sludge showed the greater methane production. The PAH removals ranged from 10% to 30%, respectively, for high and low molecular weight PAH, whatever the inoculums tested, and were highly correlated with the dry matter and volatile solid removals. The microbial community structure and diversity differed with the inoculum source; this difference was maintained after the 100 days of digestion. However, the PAH removal was not correlated to these diverse structures and diversities. We hence obtained three functional stable consortia with two contrasted metabolic activities, and three different pictures of microbial diversity, but similar PAH and matter removals. These results confirm

  13. Effect of organic load on decolourization of textile wastewater containing acid dyes in upflow anaerobic sludge blanket reactor

    International Nuclear Information System (INIS)

    Textile wastewater (TW) is one of the most hazardous wastewater for the environment when discharged without proper treatment. Biological treatment technologies have shown encouraging results over the treatment of recalcitrant compounds containing wastewaters. Upflow anaerobic sludge blanket reactor (UASB) was evaluated in terms of colour and the reduction of chemical oxygen demand (COD) with different organic loads using TW containing dyes belonging to different chemical groups. The study was performed using six different dye concentrations (10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 150 mg/L, 300 mg/L) with three COD levels (∼1000 mg/L, ∼2000 mg/L, ∼3000 mg/L). Decolourization, COD removal and reactor stability were monitored. Over 85% of colour removal was observed with all dye concentrations with three organic loads. Acid Red 131 and Acid Yellow 79 were decolourized through biodegradation while Acid Blue 204 was decolourized due to adsorption onto anaerobic granules. COD removal was high in all dye concentrations, regardless of co-substrate levels. The reactor did not show any instability during the study. The activity of granules was not affected by the dyes. Methanothrix like bacteria were the dominant group in granules before introducing TW, however, they were reduced and cocci-shape microorganism increased after the treatment of textile wastewater.

  14. Effect of organic load on decolourization of textile wastewater containing acid dyes in upflow anaerobic sludge blanket reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wijetunga, Somasiri, E-mail: swije2001@yahoo.com [Laboratory of Environmental Biotechnology, School of Biotechnology, Southern Yangtze University, 170 Huihe Road, Wuxi 214036 (China); Li Xiufen [Laboratory of Environmental Biotechnology, School of Biotechnology, Southern Yangtze University, 170 Huihe Road, Wuxi 214036 (China); Jian Chen, E-mail: jchen@sytu.edu.cn [Laboratory of Environmental Biotechnology, School of Biotechnology, Southern Yangtze University, 170 Huihe Road, Wuxi 214036 (China)

    2010-05-15

    Textile wastewater (TW) is one of the most hazardous wastewater for the environment when discharged without proper treatment. Biological treatment technologies have shown encouraging results over the treatment of recalcitrant compounds containing wastewaters. Upflow anaerobic sludge blanket reactor (UASB) was evaluated in terms of colour and the reduction of chemical oxygen demand (COD) with different organic loads using TW containing dyes belonging to different chemical groups. The study was performed using six different dye concentrations (10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 150 mg/L, 300 mg/L) with three COD levels ({approx}1000 mg/L, {approx}2000 mg/L, {approx}3000 mg/L). Decolourization, COD removal and reactor stability were monitored. Over 85% of colour removal was observed with all dye concentrations with three organic loads. Acid Red 131 and Acid Yellow 79 were decolourized through biodegradation while Acid Blue 204 was decolourized due to adsorption onto anaerobic granules. COD removal was high in all dye concentrations, regardless of co-substrate levels. The reactor did not show any instability during the study. The activity of granules was not affected by the dyes. Methanothrix like bacteria were the dominant group in granules before introducing TW, however, they were reduced and cocci-shape microorganism increased after the treatment of textile wastewater.

  15. Continuous High Rate Anaerobic Treatment of Oleic Acid Based Wastewater is Possible after a Step Feeding Start-Up

    OpenAIRE

    Cavaleiro, A. J.; Salvador, A. F.; Alves, J.I.; Alves, M. M.

    2009-01-01

    Mineralization of a synthetic effluent containing 50% COD as oleic acid was achieved in a continuous anaerobic reactor at organic loading rates up to 21 kg COD m−3 day−1, HRT of 9 h, attaining 99% of COD removal efficiency and a methane yield higher than 70%. A maximum specific methane production rate of 1170 ± 170 mg COD-CH4 g VS−1 day−1 was measured during the reactor’s operation. A start-up strategy combining feeding phases and batch degradation phases was applied to promote the developmen...

  16. PHAGE RESISTANT LACTIC ACID BACTERIAL MUTANTS

    DEFF Research Database (Denmark)

    2001-01-01

    Method of obtaining mutated lactic acid bacteria having a reduced susceptibility towards attack by bacteriophages, the method comprising mutating a gene involved in the pyrimidine metabolism, including pyrG encoding CTP synthetase. Such lactic acid bacteria are useful in starter cultures in the p......Method of obtaining mutated lactic acid bacteria having a reduced susceptibility towards attack by bacteriophages, the method comprising mutating a gene involved in the pyrimidine metabolism, including pyrG encoding CTP synthetase. Such lactic acid bacteria are useful in starter cultures...

  17. Accelerated anaerobic dechlorination of DDT in slurry with Hydragric Acrisols using citric acid and anthraquinone-2,6-disulfonate (AQDS).

    Science.gov (United States)

    Liu, Cuiying; Xu, Xianghua; Fan, Jianling

    2015-12-01

    The application of electron donor and electron shuttle substances has a vital influence on electron transfer, thus may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) in anaerobic reaction systems. To evaluate the roles of citric acid and anthraquinone-2,6-disulfonate (AQDS) in accelerating the reductive dechlorination of DDT in Hydragric Acrisols that contain abundant iron oxide, a batch anaerobic incubation experiment was conducted in a slurry system with four treatments of (1) control, (2) citric acid, (3) AQDS, and (4) citric acid+AQDS. Results showed that DDT residues decreased by 78.93%-92.11% of the initial quantities after 20days of incubation, and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane (DDD) was the dominant metabolite. The application of citric acid accelerated DDT dechlorination slightly in the first 8days, while the methanogenesis rate increased quickly, and then the acceleration effect improved after the 8th day while the methanogenesis rate decreased. The amendment by AQDS decreased the Eh value of the reaction system and accelerated microbial reduction of Fe(III) oxides to generate Fe(II), which was an efficient electron donor, thus enhancing the reductive dechlorination rate of DDT. The addition of citric acid+AQDS was most efficient in stimulating DDT dechlorination, but no significant interaction between citric acid and AQDS on DDT dechlorination was observed. The results will be of great significance for developing an efficient in situ remediation strategy for DDT-contaminated sites.

  18. Polycyclic Aromatic Hydrocarbon Affects Acetic Acid Production during Anaerobic Fermentation of Waste Activated Sludge by Altering Activity and Viability of Acetogen.

    Science.gov (United States)

    Luo, Jingyang; Chen, Yinguang; Feng, Leiyu

    2016-07-01

    Till now, almost all the studies on anaerobic fermentation of waste activated sludge (WAS) for bioproducts generation focused on the influences of operating conditions, pretreatment methods and sludge characteristics, and few considered those of widespread persistent organic pollutants (POPs) in sludge, for example, polycyclic aromatic hydrocarbons (PAHs). Herein, phenanthrene, which was a typical PAH and widespread in WAS, was selected as a model compound to investigate its effect on WAS anaerobic fermentation for short-chain fatty acids (SCFAs) accumulation. Experimental results showed that the concentration of SCFAs derived from WAS was increased in the presence of phenanthrene during anaerobic fermentation. The yield of acetic acid which was the predominant SCFA in the fermentation reactor with the concentration of 100 mg/kg dry sludge was 1.8 fold of that in the control. Mechanism exploration revealed that the present phenanthrene mainly affected the acidification process of anaerobic fermentation and caused the shift of the microbial community to benefit the accumulation of acetic acid. Further investigation showed that both the activities of key enzymes (phosphotransacetylase and acetate kinase) involved in acetic acid production and the quantities of their corresponding encoding genes were enhanced in the presence of phenanthrene. Viability tests by determining the adenosine 5'-triphosphate content and membrane potential confirmed that the acetogens were more viable in anaerobic fermentation systems with phenanthrene, which resulted in the increased production of acetic acid. PMID:27267805

  19. Adaptation of anaerobically grown Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans to organic solvents on the level of membrane fatty acid composition

    OpenAIRE

    Duldhardt, Ilka; Gaebel, Julia; Chrzanowski, Lukasz; Nijenhuis, Ivonne; Härtig, Claus; Schauer, Frieder; Heipieper, Hermann J.

    2010-01-01

    Summary The effect of different solvents and pollutants on the cellular fatty acid composition of three bacterial strains: Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans, representatives of diverse predominant anaerobic metabolisms was investigated. As the prevailing adaptive mechanism in cells of T. aromatica and G. sulfurreducens whose cellular fatty acids patterns were dominated by palmitic acid (C16:0) and palmitoleic acid (C16:1cis), the cells reacted by an inc...

  20. THE "CHEMICAL OXYGEN DEMAND / TOTAL VOLATILE ACIDS" RATIO AS AN ANAEROBIC TREATABILITY INDICATOR FOR LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    R. C. Contrera

    2015-03-01

    Full Text Available Abstract In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR. The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

  1. Anaerobic soil disinfestation: Carbon rate effects on tomato plant growth and organic acid production

    Science.gov (United States)

    Anaerobic soil disinfestation (ASD) is a non-chemical soil disinfestation technique proposed for the control of soil-borne pathogens, plant parasitic-nematodes, and weeds in different crops. ASD is applied in three steps: 1) Soil amendment with a labile carbon (C) source; 2) Cover the soil with tota...

  2. Microbial dynamics in anaerobic enrichment cultures degrading di-n-butyl phthalic acid ester

    DEFF Research Database (Denmark)

    Trably, Eric; Batstone, Damien J.; Christensen, Nina;

    2008-01-01

    , a microorganism described previously as an anaerobic benzaldehyde degrader. Within the archaeal community, there was a shift between two different species of the genus Methanosaeta sp., indicating a highly specific impact of DBP or degradation products on archaeal species. RNA-directed probes were designed from...

  3. Adaptation of anaerobically grown Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans to organic solvents on the level of membrane fatty acid composition.

    Science.gov (United States)

    Duldhardt, Ilka; Gaebel, Julia; Chrzanowski, Lukasz; Nijenhuis, Ivonne; Härtig, Claus; Schauer, Frieder; Heipieper, Hermann J

    2010-03-01

    The effect of different solvents and pollutants on the cellular fatty acid composition of three bacterial strains: Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans, representatives of diverse predominant anaerobic metabolisms was investigated. As the prevailing adaptive mechanism in cells of T. aromatica and G. sulfurreducens whose cellular fatty acids patterns were dominated by palmitic acid (C16:0) and palmitoleic acid (C16:1cis), the cells reacted by an increase in the degree of saturation of their membrane fatty acids when grown in the presence of sublethal concentrations of the chemicals. Next to palmitic acid C16:0, the fatty acid pattern of D. multivorans was dominated by anteiso-branched fatty acids which are characteristic for several sulfate-reducing bacteria. The cells responded to the solvents with an increase in the ratio of straight-chain saturated (C14:0, C16:0, C18:0) to anteiso-branched fatty acids (C15:0anteiso, C17:0anteiso, C17:1anteisoΔ9cis). The results show that anaerobic bacteria react with similar mechanisms like aerobic bacteria in order to adapt their membrane to toxic organic solvents. The observed adaptive modifications on the level of membrane fatty acid composition can only be carried out with de novo synthesis of the fatty acids which is strictly related to cell growth. As the growth rates of anaerobic bacteria are generally much lower than in the so far investigated aerobic bacteria, this adaptive response needs more time in anaerobic bacteria. This might be one explanation for the previously observed higher sensitivity of anaerobic bacteria when compared with aerobic ones. PMID:21255320

  4. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    Directory of Open Access Journals (Sweden)

    Young Hee Lee

    2014-09-01

    Full Text Available Two cultivars Buram-3-ho (susceptible and CR-Hagwang (moderate resistant of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum, black spot (Alternaria brassicicola and black rot (Xanthomonas campestris pv. campestris, Xcc diseases in our previous study. Defense-related hormones salicylic acid (SA, jasmonic acid (JA and ethylene led to different transcriptional regulation of pathogenesis-related (PR gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

  5. Fate of antibiotic resistance genes and its drivers during anaerobic co-digestion of food waste and sewage sludge based on microwave pretreatment.

    Science.gov (United States)

    Zhang, Junya; Chen, Meixue; Sui, Qianwen; Wang, Rui; Tong, Juan; Wei, Yuansong

    2016-10-01

    In this study, anaerobic digestion of mono-SS, MW-SS:FW and SS:MW-FW was investigated to understand the fate of ARGs and its drivers. Anaerobic digestion was effective for the reduction of metal resistance genes (MRGs), and could reduce the abundance of blaOXA-1, sulI and tetG, while sulII in co-digestion and blaTEM and ereA only in MW-SS. ARGs reduction could be partly attributed to the reduction of co-selective pressure from heavy metals reflected by MRGs. However, the abundance of mefA/E, ermB, ermF, tetM and tetX increased significantly. Anaerobic co-digestion, especially for MW-SS, could reduce total ARGs abundance compared with mono-SS, and evolution of bacterial community was the main driver for the fate of ARGs. PMID:26988135

  6. A novel anaerobic two-phase system for biohydrogen production and in situ extraction of organic acid byproducts.

    Science.gov (United States)

    Sarma, Saurabh Jyoti; Brar, Satinder Kaur; Le Bihan, Yann; Buelna, Gerardo

    2015-06-01

    Owing to CO2-free emission, hydrogen is considered as a potential green alternative of fossil fuels. Water is the major emission of hydrogen combustion process and gravimetric energy density of hydrogen is nearly three times more than that of gasoline and diesel fuel. Biological hydrogen production, therefore, has commercial significance; especially, when it is produced from low-cost industrial waste-based feedstock. Light independent anaerobic fermentation is simple and mostly studied method of biohydrogen production. During hydrogen production by this method, a range of organic acid byproducts are produced. Accumulation of these byproducts is inhibitory for hydrogen production as it may result in process termination due to sharp decrease in medium pH or by possible metabolic shift. For the first time, therefore, a two-phase anaerobic bioreactor system has been reported for biohydrogen production which involves in situ extraction of different organic acids. Among different solvents, based on biocompatibility oleyl alcohol has been chosen as the organic phase of the two-phase system. An organic:aqueous phase ratio of 1:50 has been found to be optimum for hydrogen production. The strategy was capable of increasing the hydrogen production from 1.48 to 11.65 mmol/L-medium.

  7. Resistance of yeasts to weak organic acid food preservatives.

    Science.gov (United States)

    Piper, Peter W

    2011-01-01

    Carboxylate weak acids are invaluable for large-scale food and beverage preservation. However, in response to safety concerns, there is now desire to reduce the use of these additives. The resistance to these compounds displayed by spoilage yeasts and fungi is a major reason why these preservatives often have to be used in millimolar levels. This chapter summarizes the mechanisms whereby yeasts are rendered resistant to acetate, propionate, sorbate, and benzoate. In baker's yeast (Saccharomyces cerevisiae), resistance to high acetic acid is acquired partly by loss of the plasma membrane aquaglyceroporin that facilitates the passive diffusional entry of undissociated acid into cells (Fps1), and partly through a transcriptional response mediated by the transcription factor Haa1. Other carboxylate preservatives are too large to enter cells through the Fps1 channel but instead penetrate at appreciable rates by passive diffusion across the plasma membrane. In Saccharomyces and Candida albicans though not, it seems, in the Zygosaccharomyces, resistance to the latter acids involves activation of the War1 transcription factor, which in turn generates strong induction of a specific plasma membrane ATP-binding cassette transporter (Pdr12). The latter actively pumps the preservative anion from the cell. Other contributors to weak acid resistance include enzymes that allow preservative degradation, members of the Tpo family of major facilitator superfamily transporters, and changes to the cell envelope that minimize the diffusional entry of the preservative into the cell.

  8. Does high serum uric acid level cause aspirin resistance?

    Science.gov (United States)

    Yildiz, Bekir S; Ozkan, Emel; Esin, Fatma; Alihanoglu, Yusuf I; Ozkan, Hayrettin; Bilgin, Murat; Kilic, Ismail D; Ergin, Ahmet; Kaftan, Havane A; Evrengul, Harun

    2016-06-01

    In patients with coronary artery disease (CAD), though aspirin inhibits platelet activation and reduces atherothrombotic complications, it does not always sufficiently inhibit platelet function, thereby causing a clinical situation known as aspirin resistance. As hyperuricemia activates platelet turnover, aspirin resistance may be specifically induced by increased serum uric acid (SUA) levels. In this study, we thus investigated the association between SUA level and aspirin resistance in patients with CAD. We analyzed 245 consecutive patients with stable angina pectoris (SAP) who in coronary angiography showed more than 50% occlusion in a major coronary artery. According to aspirin resistance, two groups were formed: the aspirin resistance group (Group 1) and the aspirin-sensitive group (Group 2). Compared with those of Group 2, patients with aspirin resistance exhibited significantly higher white blood cell counts, neutrophil counts, neutrophil-to-lymphocyte ratios, SUA levels, high-sensitivity C-reactive protein levels, and fasting blood glucose levels. After multivariate analysis, a high level of SUA emerged as an independent predictor of aspirin resistance. The receiver-operating characteristic analysis provided a cutoff value of 6.45 mg/dl for SUA to predict aspirin resistance with 79% sensitivity and 65% specificity. Hyperuricemia may cause aspirin resistance in patients with CAD and high SUA levels may indicate aspirin-resistant patients. Such levels should thus recommend avoiding heart attack and stroke by adjusting aspirin dosage. PMID:26656902

  9. Sphingolipids contribute to acetic acid resistance in Zygosaccharomyces bailii.

    Science.gov (United States)

    Lindahl, Lina; Genheden, Samuel; Eriksson, Leif A; Olsson, Lisbeth; Bettiga, Maurizio

    2016-04-01

    Lignocellulosic raw material plays a crucial role in the development of sustainable processes for the production of fuels and chemicals. Weak acids such as acetic acid and formic acid are troublesome inhibitors restricting efficient microbial conversion of the biomass to desired products. To improve our understanding of weak acid inhibition and to identify engineering strategies to reduce acetic acid toxicity, the highly acetic-acid-tolerant yeast Zygosaccharomyces bailii was studied. The impact of acetic acid membrane permeability on acetic acid tolerance in Z. bailii was investigated with particular focus on how the previously demonstrated high sphingolipid content in the plasma membrane influences acetic acid tolerance and membrane permeability. Through molecular dynamics simulations, we concluded that membranes with a high content of sphingolipids are thicker and more dense, increasing the free energy barrier for the permeation of acetic acid through the membrane. Z. bailii cultured with the drug myriocin, known to decrease cellular sphingo-lipid levels, exhibited significant growth inhibition in the presence of acetic acid, while growth in medium without acetic acid was unaffected by the myriocin addition. Furthermore, following an acetic acid pulse, the intracellular pH decreased more in myriocin-treated cells than in control cells. This indicates a higher inflow rate of acetic acid and confirms that the reduction in growth of cells cultured with myriocin in the medium with acetic acid was due to an increase in membrane permeability, thereby demonstrating the importance of a high fraction of sphingolipids in the membrane of Z. bailii to facilitate acetic acid resistance; a property potentially transferable to desired production organisms suffering from weak acid stress.

  10. Investigation into the effect of high concentrations of volatile fatty acids in anaerobic digestion on methanogenic communities

    Energy Technology Data Exchange (ETDEWEB)

    Franke-Whittle, Ingrid H., E-mail: ingrid.whittle@uibk.ac.at [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Walter, Andreas [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Ebner, Christian [Abwasserverband Zirl und Umgebung, Meilbrunnen 5, 6170 Zirl (Austria); Insam, Heribert [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria)

    2014-11-15

    Highlights: • Different methanogenic communities in mesophilic and thermophilic reactors. • High VFA levels do not cause major changes in archaeal communities. • Real-time PCR indicated greater diversity than ANAEROCHIP microarray. - Abstract: A study was conducted to determine whether differences in the levels of volatile fatty acids (VFAs) in anaerobic digester plants could result in variations in the indigenous methanogenic communities. Two digesters (one operated under mesophilic conditions, the other under thermophilic conditions) were monitored, and sampled at points where VFA levels were high, as well as when VFA levels were low. Physical and chemical parameters were measured, and the methanogenic diversity was screened using the phylogenetic microarray ANAEROCHIP. In addition, real-time PCR was used to quantify the presence of the different methanogenic genera in the sludge samples. Array results indicated that the archaeal communities in the different reactors were stable, and that changes in the VFA levels of the anaerobic digesters did not greatly alter the dominating methanogenic organisms. In contrast, the two digesters were found to harbour different dominating methanogenic communities, which appeared to remain stable over time. Real-time PCR results were inline with those of microarray analysis indicating only minimal changes in methanogen numbers during periods of high VFAs, however, revealed a greater diversity in methanogens than found with the array.

  11. Metabolic potential of fatty acid oxidation and anaerobic respiration by abundant members of Thaumarchaeota and Thermoplasmata in deep anoxic peat

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Xueju [Georgia Inst. of Technology, Atlanta, GA (United States); Handley, Kim M. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Gilbert, Jack A. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Marine Biological Lab., Woods Hole, MA (United States); Zhejiang Univ., Hangzhou (China); Kostka, Joel E. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2015-05-22

    To probe the metabolic potential of abundant Archaea in boreal peats, we reconstructed two near-complete archaeal genomes, affiliated with Thaumarchaeota group 1.1c (bin Fn1, 8% abundance), which was a genomically unrepresented group, and Thermoplasmata (bin Bg1, 26% abundance), from metagenomic data acquired from deep anoxic peat layers. Each of the near-complete genomes encodes the potential to degrade long-chain fatty acids (LCFA) via β-oxidation. Fn1 has the potential to oxidize LCFA either by syntrophic interaction with methanogens or by coupling oxidation with anaerobic respiration using fumarate as a terminal electron acceptor (TEA). Fn1 is the first Thaumarchaeota genome without an identifiable carbon fixation pathway, indicating that this mesophilic phylum encompasses more diverse metabolisms than previously thought. Furthermore, we report genetic evidence suggestive of sulfite and/or organosulfonate reduction by Thermoplasmata Bg1. In deep peat, inorganic TEAs are often depleted to extremely low levels, yet the anaerobic respiration predicted for two abundant archaeal members suggests organic electron acceptors such as fumarate and organosulfonate (enriched in humic substances) may be important for respiration and C mineralization in peatlands.

  12. An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid.

    Science.gov (United States)

    Li, Xiaoming; Zhao, Jianwei; Wang, Dongbo; Yang, Qi; Xu, Qiuxiang; Deng, Yongchao; Yang, Weiqiang; Zeng, Guangming

    2016-02-01

    Short-chain fatty acid (SCFA) production from waste activated sludge (WAS) anaerobic fermentation is often limited by the slow hydrolysis rate and poor substrate availability, thus a long fermentation time is required. This paper reports a new pretreatment approach, i.e., using free nitrous acid (FNA) to pretreat sludge, for significantly enhanced SCFA production. Experimental results showed the highest SCFA production occurred at 1.8 mg FNA/L with time of day 6, which was 3.7-fold of the blank at fermentation time of day 12. Mechanism studies revealed that FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. It was also found that FNA pretreatment benefited hydrolysis and acidification processes but inhibited the activities of methanogens, thereby promoting the yield of SCFA. In addition, the FNA pretreatment substantially stimulated the activities of key enzymes responsible for hydrolysis and acidification, which were consistent with the improvement of solubilization, hydrolysis and acidification of WAS anaerobic fermentation. PMID:26363316

  13. An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid.

    Science.gov (United States)

    Li, Xiaoming; Zhao, Jianwei; Wang, Dongbo; Yang, Qi; Xu, Qiuxiang; Deng, Yongchao; Yang, Weiqiang; Zeng, Guangming

    2016-02-01

    Short-chain fatty acid (SCFA) production from waste activated sludge (WAS) anaerobic fermentation is often limited by the slow hydrolysis rate and poor substrate availability, thus a long fermentation time is required. This paper reports a new pretreatment approach, i.e., using free nitrous acid (FNA) to pretreat sludge, for significantly enhanced SCFA production. Experimental results showed the highest SCFA production occurred at 1.8 mg FNA/L with time of day 6, which was 3.7-fold of the blank at fermentation time of day 12. Mechanism studies revealed that FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. It was also found that FNA pretreatment benefited hydrolysis and acidification processes but inhibited the activities of methanogens, thereby promoting the yield of SCFA. In addition, the FNA pretreatment substantially stimulated the activities of key enzymes responsible for hydrolysis and acidification, which were consistent with the improvement of solubilization, hydrolysis and acidification of WAS anaerobic fermentation.

  14. Novel acid resistance genes from the metagenome of the Tinto River, an extremely acidic environment.

    Science.gov (United States)

    Guazzaroni, María-Eugenia; Morgante, Verónica; Mirete, Salvador; González-Pastor, José E

    2013-04-01

    Microorganisms that thrive in acidic environments are endowed with specialized molecular mechanisms to survive under this extremely harsh condition. In this work, we performed functional screening of six metagenomic libraries from planktonic and rhizosphere microbial communities of the Tinto River, an extremely acidic environment, to identify genes involved in acid resistance. This approach has revealed 15 different genes conferring acid resistance to Escherichia coli, most of which encoding putative proteins of unknown function or previously described proteins not known to be related to acid resistance. Moreover, we were able to assign function to one unknown and three hypothetical proteins. Among the recovered genes were the ClpXP protease, the transcriptional repressor LexA and nucleic acid-binding proteins such as an RNA-binding protein, HU and Dps. Furthermore, nine of the retrieved genes were cloned and expressed in Pseudomonas putida and Bacillus subtilis and, remarkably, most of them were able to expand the capability of these bacteria to survive under severe acid stress. From this set of genes, four presented a broad-host range as they enhance the acid resistance of the three different organisms tested. These results expand our knowledge about the different strategies used by microorganisms to survive under extremely acid conditions. PMID:23145860

  15. A bioprocess for the remediation of anaerobically digested molasses spentwash from biogas plant and simultaneous production of lactic acid

    Energy Technology Data Exchange (ETDEWEB)

    Shibu, A.R.; Kumar, V.; Wati, L.; Chaudhary, K.; Singh, D. [Department of Microbiology, CCS Haryana Agricultural Univ., Hisar (India); Nigam, P. [Biotechnology Research Group, University of Ulster (United Kingdom)

    1999-04-01

    A bacterial isolate LAB-1 identified as Lactobacillus casei was cultivated in a fermentation medium containing biogas plant effluent. This effluent was generated after anaerobic digestion of molasses spentwash in biogas fermenters. In the bioremediation process of this very dark coloured effluent through the cultivation of L. casei, decrease in effluent`s colour of 49 and 52% and reduction in COD level up to 54 and 57% were achieved using bacterial cells in free and immobilised system, respectively, in 5 days batch cultivation. During this process of bioremediation, a metabolite lactic acid was produced by this bacterial isolate with the yield of 10.9 and 11.3 mg/ml, in free and immobilised cells fermentation, respectively. (orig.) With 3 figs., 2 tabs., 14 refs.

  16. Fatty Acids Profile during Anaerobic Digestion of Night Soil-Effect of temperature, Calcium Carbonate and Selectively-enriched Inoculum

    Directory of Open Access Journals (Sweden)

    S. I. Alam

    1996-01-01

    Full Text Available Anaerobic biodegradation of night soil was carried out at 5-30 degree centigrade with 1.8-10.62 per cent volatile solids (VS. Biogas production increased with the temperature and VS up to 6.2 per cent. Further increase in VS caused higher Volatile fatty acids (VFA accumulation resulting in decreased gas production. Acetate and propionate accounted for 62-83 per cent of total VFA. Butyrate to isobutyrate ratio increased with VS. Calcium Carbonate promoted VS degradation, biogas production and VFA degradation. The increased methanogenic and decreased sulphate-reducing bacteria caused proportional changes in CH4 and H2S gases. Enrichment with H2 oxidising methanogenic consortium is beneficial by enhancing VFA utilisation by two to three fold.

  17. Development of a submerged anaerobic membrane bioreactor for concurrent extraction of volatile fatty acids and biohydrogen production.

    Science.gov (United States)

    Trad, Zaineb; Akimbomi, Julius; Vial, Christophe; Larroche, Christian; Taherzadeh, Mohammad J; Fontaine, Jean-Pierre

    2015-11-01

    The aim of this work was to study an externally-submerged membrane bioreactor for the cyclic extraction of volatile fatty acids (VFAs) during anaerobic fermentation, combining the advantages of submerged and external technologies for enhancing biohydrogen (BioH2) production from agrowaste. Mixing and transmembrane pressure (TMP) across a hollow fiber membrane placed in a recirculation loop coupled to a stirred tank were investigated, so that the loop did not significantly modify the hydrodynamic properties in the tank. The fouling mechanism, due to cake layer formation, was reversible. A cleaning procedure based on gas scouring and backwashing with the substrate was defined. Low TMP, 10(4)Pa, was required to achieve a 3Lh(-1)m(-2) critical flux. During fermentation, BioH2 production was shown to restart after removing VFAs with the permeate, so as to enhance simultaneously BioH2 production and the recovery of VFAs as platform molecules.

  18. Co-occurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in subtropical acidic forest soils.

    Science.gov (United States)

    Meng, Han; Wang, Yong-Feng; Chan, Ho-Wang; Wu, Ruo-Nan; Gu, Ji-Dong

    2016-09-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two new processes of recent discoveries linking the microbial nitrogen and carbon cycles. In this study, 16S ribosomal RNA (rRNA) gene of anammox bacteria and pmoA gene of n-damo bacteria were used to investigate their distribution and diversity in natural acidic and re-vegetated forest soils. The 16S rRNA gene sequences retrieved featured at least three species in two genera known anammox bacteria, namely Candidatus Brocadia anammoxidans, Candidatus Brocadia fulgida, and Candidatus Kuenenia stuttgartiensis while the pmoA gene amplified was affiliated with two species of known n-damo bacteria Candidatus Methylomirabilis oxyfera and a newly established Candidatus Methylomirabilis sp. According to the results, the diversity of anammox bacteria in natural forests was lower than in re-vegetated forests, but no significant difference was observed in n-damo community between them. Quantitative real-time PCR showed that both anammox and n-damo bacteria were more abundant in the lower layer (10-20 cm) than the surface layer (0-5 cm). The abundance of anammox bacteria varied from 2.21 × 10(5) to 3.90 × 10(6) gene copies per gram dry soil, and n-damo bacteria quantities were between 1.69 × 10(5) and 5.07 × 10(6) gene copies per gram dry soil in the two different layers. Both anammox and n-damo bacteria are reported for the first time to co-occur in acidic forest soil in this study, providing a more comprehensive information on more defined microbial processes contributing to C and N cycles in the ecosystems. PMID:27178181

  19. Influence of cyclopropane fatty acids on heat, high pressure, acid and oxidative resistance in Escherichia coli.

    Science.gov (United States)

    Chen, Yuan Yao; Gänzle, Michael G

    2016-04-01

    Heat and high pressure resistant strains of Escherichia coli are a challenge to food safety. This study investigated effects of cyclopropane fatty acids (CFAs) on stress tolerance in the heat- and pressure-resistant strain E. coli AW1.7 and the sensitive strain E. coli MG1655. The role of CFAs was explored by disruption of cfa coding for CFA synthase with an in-frame, unmarked deletion method. Both wild-type strains consumed all the unsaturated fatty acids (C16:1 and C18:1) that were mostly converted to CFAs and a low proportion to saturated fatty acid (C16:0). Moreover, E. coli AW1.7 contained a higher proportion of membrane C19:0 cyclopropane fatty acid than E. coli MG1655 (Phigh pressure and acid treatments in E. coli AW1.7, and E. coli MG1655. E. coli AW1.7 and its Δcfa mutant were more resistant to pressure and heat but less resistant to acid stress than E. coli MG1655. Heat resistance of wild-type strains and their Δcfa mutant was also assessed in beef patties grilled to an internal temperature of 71 °C. After treatment, cell counts of wild type strains were higher than those of the Δcfa mutant strains. In conclusion, CFA synthesis in E. coli increases heat, high pressure and acid resistance, and increases heat resistance in food. This knowledge on mechanisms of stress resistance will facilitate the design of intervention methods for improved pathogen control in food production.

  20. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, November 1993--November 1994

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.

    1994-12-06

    Factors influencing the rate and extent of benzoate degradation by the anaerobic syntrophic consortia were studied. Nonlinear regression analysis showed that the cause of the benzoate threshold was not a diminished benzoate degradation capacity. Analysis of cocultures with hydrogen users that differed in their hydrogen utilization capacities showed that the threshold did not depend on the kinetic properties of the syntrophic partner. These data support a thermodynamic explanation for the threshold, and exclude the possibility that a change in the affinity of the enzyme system due to acetate inhibition caused the threshold. Modeling studies showed that the threshold value could be predicted from the concentrations of the end products, assuming a critical Gibb`s free energy value. This work shows that interspecies acetate transfer is important in controlling the extent of metabolism by syntrophic organisms.

  1. Energetics and kinetics of anaerobic aromatic and fatty acid degradation. Progress report, November 1992--November 1993

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.

    1993-11-12

    The kinetics of benzoate degradation by the anaerobic syntrophic bacterium, Syntrophus buswellii, in coculture with different sulfate reducers was studied with sulfate or nitrate as the electron acceptor. A threshold value for benzoate degradation dependent on the acetate concentration was observed with sulfate, but not nitrate, as the electron acceptor. No threshold was observed in tricultures containing an acetate-using sulfate reducer. The addition of the acetate-using sulfate reducer to cocultures that had degraded benzoate to its threshold value resulted in further degradation of benzoate to levels below the analytical detection limit (ca. 200 nM). These data are consistent with a thermodynamic explanation for the threshold, and exclude the possibility that the threshold was the result of the inhibitory action of the undissociated form of acetate.

  2. The role of anaerobic digestion in controlling the release of tetracycline resistance genes and class 1 integrons from municipal wastewater treatment plants.

    Science.gov (United States)

    Ghosh, Sudeshna; Ramsden, Sara J; LaPara, Timothy M

    2009-09-01

    In this study, the abilities of two anaerobic digestion processes used for sewage sludge stabilization were compared for their ability to reduce the quantities of three genes that encode resistance to tetracycline (tet(A), tet(O), and tet(X)) and one gene involved with integrons (intI1). A two-stage, thermophilic/mesophilic digestion process always resulted in significant decreases in the quantities of tet(X) and intI1, less frequently in decreases of tet(O), and no net decrease in tet(A). The thermophilic stage was primarily responsible for reducing the quantities of these genes, while the subsequent mesophilic stage sometimes caused a rebound in their quantities. In contrast, a conventional anaerobic digestion process rarely caused a significant decrease in the quantities of any of these genes, with significant increases occurring more frequently. Our results demonstrate that anaerobic thermophilic treatment was more efficient in reducing quantities of genes associated with the spread of antibiotic resistance compared to mesophilic digestion. PMID:19597810

  3. Efficient Anaerobic Fermentation of Simple Sugars by Yeast Fuels Resistance Candida spp. Infections to Eradication by Drugs

    Directory of Open Access Journals (Sweden)

    Nedosa I. Valentine

    2011-01-01

    Full Text Available Problem statement: Human systemic Candida infections had proved difficult to eradicate by the medical health care system. Some practitioners and scholars see the problem as being due to drug resistance. For example an author wrote that ‘secondary drug resistance is clearly being encountered in one setting, oropharyngeal candidiasis in patients with advanced Human Immunodeficiency Virus type 1 (HIV-1 infection usually following years or months of azole therapy. Approach: This research work understudied the nutritional strategies of yeast colonies to serve as a guide to understanding the survival strategies of Candida colonies in human Candidiasis. The aim of the research was to make some impute into more effective ways of eradicating human Candida infections. Ethanol was produced biologically by fermentation of sugar by micro-organisms. The yeast Saccaromyces cerevisiae metabolises complex carbohydrates like starch in the absence of oxygen to ethanol, carbon dioxide and water. This study compared the average ethanol yield of hydrolyzed and unhydrolyzed gelatinized cassava starch fermented by Saccharomyces cerevisiae. The starch was hydrolyzed by α and β-amylase enzymes. Fermentation of the starch was done with a 1% innoculums of a 12 h culture of saccharomyces cerevisiae incubated for 48 h under anaerobic conditions. Results: The results of the study showed that there was no starch hydrolysis in the absence of α and β-amylase enzymes. Starch hydrolysis in the presence of α and β-amylase enzyme took 1 h. There was no starch fermentation in the absence of saccharomyces cerevisiae. The ethanol yield of starch which had been hydrolyzed by α and β-amylases prior to fermentation by saccharomyces cerevisae was 28 times higher than the ethanol yield of starch which had not been previously hydrolyzed by α and β-amylases. These results of the study suggest that yeast infections in human and animal tissues produce 28 times more ethanol yield from

  4. Research Advances in the Inhibition of Long Chain Fatty Acid to Methanogenic Activity in Anaerobic Digestion System%长链脂肪酸对厌氧消化产沼的抑制作用研究进展

    Institute of Scientific and Technical Information of China (English)

    赵芳; 李江华; 董滨; 何群彪; 戴玲玲; 戴晓虎

    2012-01-01

    [Objective]To isolate and identify lactobacillus in intestines of Langshan chicken, so as to provide basis for developing new probi-otics for poultry.[Method]The lactobacillus was separated from Langshan chicken intestinal by anaerobic cultivation and then identified by the analysis of physiological, biochemical properties, and the sequence homology and evolution relationship. The bacteria was screened through acid resistance and antimicrobial activity.[Result]Five strains of lactobacillus with potential probiotics of LCr-01, LCr-02, LCe-01 , LCe-02 and LCe-03 were isolated through the physiological and biochemical tests. LCr-01 and LCe-01 were identified as Lactobacillus planta-rum, LCr-02 was identified as Lactobacillus acidophilus, LCe-02 was identified as Lactobacillus delbrueckii, LCe-03 was identified as Lactobacil lus crispatus. And LCr-02 had acid resistance and significant antimicrobial activity.[Conclusion]LCr-02 of five strains lactobacillus had strong acid resistance and significant antimicrobial activity.%综述了长链脂肪酸对厌氧系统产生抑制作用的机理,深入分析了长链脂肪酸抑制作用的影响因素,概述了缓解其抑制作用的方法,并对进一步研究长链脂肪酸在厌氧消化系统中的影响做了建议.

  5. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: enhanced removal of aromatic amines.

    Science.gov (United States)

    Koupaie, E Hosseini; Moghaddam, M R Alavi; Hashemi, S H

    2011-11-15

    The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  6. Development of an Acid Resistant Concrete: A Review

    Directory of Open Access Journals (Sweden)

    Anwar Khitab

    2013-11-01

    Full Text Available This review paper addresses the measures taken to prevent or minimize the deterioration of concrete, which confronts an acidic environment. Primarily, the mechanism of reaction between alkaline concrete and acid is clearly demonstrated. The mechanism of reaction clearly sets guidelines as to how the chances of this disastrous reaction should be minimized or eliminated at all. The suggested preventive measures are two-fold i.e. the improvement of the basic microstructure of concrete and the provision of barriers against acids. Concrete can be made acid resistant using classical as well as novel techniques like nanotechnology.   There exists an immense need that these measures are recognized and implemented by the construction industry to put a stop to huge money losses.

  7. Temperature and solids retention time control microbial population dynamics and volatile fatty acid production in replicated anaerobic digesters

    Science.gov (United States)

    Vanwonterghem, Inka; Jensen, Paul D.; Rabaey, Korneel; Tyson, Gene W.

    2015-02-01

    Anaerobic digestion is a widely used technology for waste stabilization and generation of biogas, and has recently emerged as a potentially important process for the production of high value volatile fatty acids (VFAs) and alcohols. Here, three reactors were seeded with inoculum from a stably performing methanogenic digester, and selective operating conditions (37°C and 55°C 12 day and 4 day solids retention time) were applied to restrict methanogenesis while maintaining hydrolysis and fermentation. Replicated experiments performed at each set of operating conditions led to reproducible VFA production profiles which could be correlated with specific changes in microbial community composition. The mesophilic reactor at short solids retention time showed accumulation of propionate and acetate (42 +/- 2% and 15 +/- 6% of CODhydrolyzed, respectively), and dominance of Fibrobacter and Bacteroidales. Acetate accumulation (>50% of CODhydrolyzed) was also observed in the thermophilic reactors, which were dominated by Clostridium. Under all tested conditions, there was a shift from acetoclastic to hydrogenotrophic methanogenesis, and a reduction in methane production by >50% of CODhydrolyzed. Our results demonstrate that shortening the SRT and increasing the temperature are effective strategies for driving microbial communities towards controlled production of high levels of specific volatile fatty acids.

  8. Synergism and effect of high initial volatile fatty acid concentrations during food waste and pig manure anaerobic co-digestion.

    Science.gov (United States)

    Dennehy, Conor; Lawlor, Peadar G; Croize, Thomas; Jiang, Yan; Morrison, Liam; Gardiner, Gillian E; Zhan, Xinmin

    2016-10-01

    Anaerobic co-digestion of food waste (FW) and pig manure (PM) was undertaken in batch mode at 37°C in order to identify and quantify the synergistic effects of co-digestion on the specific methane yield (SMY) and reaction kinetics. The effects of the high initial volatile fatty acid (VFA) concentrations in PM on synergy observed during co-digestion, and on kinetic modelling were investigated. PM to FW mixing ratios of 1/0, 4/1, 3/2, 2/3, 1/4 and 0/1 (VS basis) were examined. No VFA or ammonia inhibition was observed. The highest SMY of 521±29ml CH4/gVS was achieved at a PM/FW mixing ratio of 1/4. Synergy in terms of both reaction kinetics and SMY occurred at PM/FW mixing ratios of 3/2, 2/3 and 1/4. Initial VFA concentrations did not explain the synergy observed. Throughout the study the conversion of butyric acid was inhibited. Due to the high initial VFA content of PM, conventional first order and Gompertz models were inappropriate for determining reaction kinetics. A dual pooled first order model was found to provide the best fit for the data generated in this study. The optimal mixing ratio in terms of both reaction kinetics and SMY was found at a PM/FW mixing ratio of 1/4. PMID:27389859

  9. Application of horizontal-flow anaerobic immobilized biomass reactor for bioremediation of acid mine drainage.

    Science.gov (United States)

    Rodriguez, R P; Vich, D V; Garcia, M L; Varesche, M B A; Zaiat, M

    2016-06-01

    The production of low-pH effluent with sulfate and metals is one of the biggest environmental concerns in the mining industry. The biological process for sulfate reduction has the potential to become a low-cost solution that enables the recovery of interesting compounds. The present study analyzed such a process in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor, employing ethanol as the carbon and energy source. Results showed that a maximal efficiency in the removal of sulfate and ethanol could only be obtained by reducing the applied sulfate load (225.1 ± 38 g m(-3) d(-1)). This strategy led to over 75% of chemical oxygen demand (COD) and sulfate removal. Among the COD/SO4(2-) studied ratios, 0.67 showed the most promising performance. The effluent's pH has naturally remained between 6.8 and 7.0 and the complete oxidation of the organic matter has been observed. Corrections of the influent pH or effluent recirculation did not show any significant effect on the COD and sulfate removal efficiency. Species closely related to strains of Clostridium sp. and species of Acidaminobacter hydrogenomorfans and Fusibacter paucivorans that can be related to the process of sulfate reduction were found in the HAIB reactors when the initial pH was 5 and the COD/SO4(2-) ratio increased to 1.0. PMID:27280606

  10. The role of acid incubation in rapid immobilization of hydrogen-producing culture in anaerobic upflow column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhen-Peng; Tay, Joo-Hwa [School of Civil and Environmental Engineering, Nanyang Technological University (Singapore); Institute of Environmental Science and Engineering, Nanyang Technological University (Singapore); Show, Kuan-Yeow [Faculty of Science, Engineering and Technology, University Tunku Abdul Rahman, 31900 Kampar, Perak (Malaysia); Liang, David Tee [Institute of Environmental Science and Engineering, Nanyang Technological University (Singapore); Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Su, Ay [Department of Mechanical Engineering, Fuel Cell Center, Yuan-Ze University, Taoyuan 320 (China)

    2008-10-15

    An approach of acidification was examined on formation of hydrogen-producing granules and biofilms in upflow column-shaped reactors. The reactors were fed with synthetic glucose wastewater and operated at 37 C and pH 5.5. The acclimated anaerobic culture was inoculated in four reactors designated R1, R2, R3 and R4, with R3 and R4 filled with granular activated carbon as support medium. To unveil the roles of acidification, microbial culture in R2 and R3 was subject to an acid incubation for 24 h by shifting the culture pH from 5.5 to 2.0. The experimental results suggested that the acidification substantially accelerated microbial granulation, but not biofilm formation. Microbial activities were inhibited by the acid incubation for about 78 h, resulting in the retarded formation of biofilms of the acidified culture. Reducing culture pH resulted in improvement in cell surface physicochemical properties favoring microbial adhesion and immobilization. Zeta potential increased from -25.3 mV to 11.9 mV, hydrophobicity in terms of contact angle improved from 31 to 38 and production of extracellular polymers increased from 66 mg/g-VSS to 136 mg/g-VSS. As a result of the formation of granules and biofilms, high hydrogen production rates of 6.98 and 7.49 L/L h were achieved in granule-based and biofilm-based reactors, respectively. It is concluded that acid incubation is an efficient means to initiate the rapid formation of granules by regulating the surface characteristics of microbial culture. The use of support media as starting nuclei may result in rapid formation of biofilms without the acidification. (author)

  11. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini Koupaie, E., E-mail: ehssan.hosseini.k@gmail.com [Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of); Alavi Moghaddam, M.R., E-mail: alavim@yahoo.com [Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of); Hashemi, S.H., E-mail: h_hashemi@sbu.ac.ir [Environmental Science Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2011-11-15

    Highlights: {yields} Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. {yields} More than 65% of the dye total metabolites was completely mineralized. {yields} Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. {yields} Inhibition of biofilm growth was increased with increasing the initial dye concentration. {yields} Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  12. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

    International Nuclear Information System (INIS)

    Highlights: → Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. → More than 65% of the dye total metabolites was completely mineralized. → Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. → Inhibition of biofilm growth was increased with increasing the initial dye concentration. → Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  13. Altered Cultivar Resistance of Kimchi Cabbage Seedlings Mediated by Salicylic Acid, Jasmonic Acid and Ethylene

    OpenAIRE

    Lee, Young Hee; Kim, Sang Hee; Yun, Byung-Wook; Hong, Jeum Kyu

    2014-01-01

    Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultiva...

  14. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided.

  15. Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts.

    Science.gov (United States)

    Zhou, N; Zhang, J X; Fan, M T; Wang, J; Guo, G; Wei, X Y

    2012-09-01

    The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.

  16. Resistance to antibiotics in Lacid acid bacteria - strain Lactococcus

    Directory of Open Access Journals (Sweden)

    Filipić Brankica

    2015-01-01

    Full Text Available Lactic acid bacteria (LAB are widely used in the food industry, especially in the production of fermented dairy products and meat. The most studied species among Lis Lactococcus lactis. L. lactis strains are of great importance in the production of fermented dairy products such as yogurt, butter, fresh cheese and some kind of semi-hard cheese. Although L. lactis acquired the „Generally Regarded As Safe“ (GRAS status, many investigations indicated that lactococci may act as reservoirs of antibiotic resistance genes, which could be transferred to other bacterial species in human gastrointestinal tract includ­ing pathogens. The genome analysis of L. lactis indicated the presence of at least 40 putative drug transporter genes, and only four multidrug resistance (MDR transporters are functionally characterized: LmrA, LmrP, LmrCD i CmbT. LmrA is the first described MDR transporter in prokaryotes. LmrCD is responsible for resistance to cholate, which is an integral part of human bile and LmrCD is important for intestinal survival of lactococci that are used as probiotics. Secondary multidrug transporter LmrP confers resistance to lincosamides, macrolides, streptogramins and tetracyclines. CmbT protein has an effect on the host cell resistance to lincomycin, sulfadiazine, streptomycin, rifampicin, puromycin and sulfametox­azole. Since the food chain is an important way of transmitting resistance genes in human and animal population, it is of great importance to study the mechanisms of resistance in lactococci and other LAB, intended for the food industry. [Projekat Ministarstva nauke Republike Srbije, br. 173019: Izučavanje gena i molekularnih mehanizama u osnovi probiotičke aktivnosti bakterija mlečne kiseline izolovanih sa područja Zapadnog Balkana

  17. Biochemical and Structural Studies of NADH-Dependent FabG Used To Increase the Bacterial Production of Fatty Acids under Anaerobic Conditions

    OpenAIRE

    Javidpour, Pouya; Pereira, Jose H.; Goh, Ee-Been; McAndrew, Ryan P.; Ma, Suzanne M.; Friedland, Gregory D.; Keasling, Jay D.; Chhabra, Swapnil R; Adams, Paul D.; Beller, Harry R.

    2014-01-01

    Major efforts in bioenergy research have focused on producing fuels that can directly replace petroleum-derived gasoline and diesel fuel through metabolic engineering of microbial fatty acid biosynthetic pathways. Typically, growth and pathway induction are conducted under aerobic conditions, but for operational efficiency in an industrial context, anaerobic culture conditions would be preferred to obviate the need to maintain specific dissolved oxygen concentrations and to maximize the propo...

  18. Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage

    Science.gov (United States)

    Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial ins...

  19. Corrosion behavior of corrosion resistant alloys in stimulation acids

    Energy Technology Data Exchange (ETDEWEB)

    Cheldi, Tiziana [ENI E and P Division, 20097 San Donato Milanese Milano (Italy); Piccolo, Eugenio Lo; Scoppio, Lucrezia [Centro Sviluppo Materiali, via Castel Romano 100, 00128 Rome (Italy)

    2004-07-01

    In the oil and gas industry, selection of CRAs for downhole tubulars is generally based on resistance to corrosive species in the production environment containing CO{sub 2}, H{sub 2}S, chloride and in some case elemental sulphur. However, there are non-production environments to which these materials must also be resistant for either short term or prolonged duration; these environments include stimulation acids, brine and completion fluids. This paper reports the main results of a laboratory study performed to evaluate the corrosion and stress corrosion behaviour to the acidizing treatments of the most used CRAs for production tubing and casing. Laboratory tests were performed to simulate both 'active' and 'spent' acids operative phases, selecting various environmental conditions. The selected steel pipes were a low alloyed steel, martensitic, super-martensitic, duplex 22 Cr, superduplex 25 Cr and super-austenitic stainless steels (25 Cr 35 Ni). Results obtained in the 'active' acid environments over the temperature range of 100-140 deg. C, showed that the blend acids with HCl at high concentration and HCl + HF represented too much severe conditions, where preventing high general corrosion and heavy localised corrosion by inhibition package becomes very difficult, especially for duplex steel pipe, where, in some case, the specimens were completely dissolved into the solution. On the contrary, all steels pipes were successfully protected by inhibitor when organic acid solution (HCOOH + CH{sub 3}COOH) were used. Furthermore, different effectiveness on corrosion protection was showed by the tested inhibitors packages: e.g. in the 90% HCl at 12% + 10 CH{sub 3}COOH acid blend. In 'spent' acid environments, all steel pipes showed to be less susceptible to the localised and general corrosion attack. Moreover, no Sulphide Stress Corrosion Cracking (SSC) was observed. Only one super-austenitic stainless steel U-bend specimen showed

  20. Ciprofloxacin, a quinolone carboxylic acid compound active against aerobic and anaerobic bacteria.

    OpenAIRE

    Chin, N X; Neu, H C

    1984-01-01

    The in vitro activity of ciprofloxacin, a quinolone-carboxylic acid derivative, was compared with those of norfloxacin, cefotaxime, cephalexin, ceftazidime, moxalactam, amoxicillin, and methicillin and other agents, as appropriate. The MICs of ciprofloxacin for 90% of members of the family Enterobacteriaceae and for Pseudomonas aeruginosa, Neisseria spp., and Bacteroides fragilis were between 0.005 and 0.8 micrograms/ml, whereas streptococci and staphylococci were all inhibited by less than o...

  1. The effects of anaerobic training in serum lipids and arachidonic acid metabolites

    OpenAIRE

    GEORGIOS KIPREOS; ALEXANDRA TRIPOLITSIOTI; APOSTOLOS STERGIOULAS

    2010-01-01

    Coronary arteries are subjected daily in high shear stress and manifest atherosclerosis very early in life in comparison to other arteries in the human body. Some factors that are implicated in the evolution and progress of this process are the concentration of lipids and arachidonic acid metabolites, such prostacyclin and thromboxane. It has been reported that those who participate in aerobic activities such as walking, cycling, jogging or brisk walking might have normal values of the mentio...

  2. Pipecolic acid enhances resistance to bacterial infection and primes salicylic acid and nicotine accumulation in tobacco.

    Science.gov (United States)

    Vogel-Adghough, Drissia; Stahl, Elia; Návarová, Hana; Zeier, Juergen

    2013-11-01

    Distinct amino acid metabolic pathways constitute integral parts of the plant immune system. We have recently identified pipecolic acid (Pip), a lysine-derived non-protein amino acid, as a critical regulator of systemic acquired resistance (SAR) and basal immunity to bacterial infection in Arabidopsis thaliana. In Arabidopsis, Pip acts as an endogenous mediator of defense amplification and priming. For instance, Pip conditions plants for effective biosynthesis of the phenolic defense signal salicylic acid (SA), accumulation of the phytoalexin camalexin, and expression of defense-related genes. Here, we show that tobacco plants respond to leaf infection by the compatible bacterial pathogen Pseudomonas syringae pv tabaci (Pstb) with a significant accumulation of several amino acids, including Lys, branched-chain, aromatic, and amide group amino acids. Moreover, Pstb strongly triggers, alongside the biosynthesis of SA and increases in the defensive alkaloid nicotine, the production of the Lys catabolites Pip and α-aminoadipic acid. Exogenous application of Pip to tobacco plants provides significant protection to infection by adapted Pstb or by non-adapted, hypersensitive cell death-inducing P. syringae pv maculicola. Pip thereby primes tobacco for rapid and strong accumulation of SA and nicotine following bacterial infection. Thus, our study indicates that the role of Pip as an amplifier of immune responses is conserved between members of the rosid and asterid groups of eudicot plants and suggests a broad practical applicability for Pip as a natural enhancer of plant disease resistance.

  3. Studies of acid resistance characteristics in multiple drug resistant Salmonella species isolated from tomatoes.

    Science.gov (United States)

    Naushad, Z; Mishra, S H; Musaddiq, M; Ali, Y A

    2013-04-01

    Salmonella species found to have a great potential of causing a variety of diseases ranging from gastroenteritis to enteric fever. Salmonella have been isolated from all food, animals and also found in the vegetables such as tomatoes, spinach etc. Several out breaks of Salmonellosis have been associated with the consumption of raw tomatoes. This is because of the fact that Salmonella attaches to the surface of tomatoes and also present in the interior part due to geotropic transmission via contaminated soil irrigated with contaminated water. .During the life cycle, Salmonella encounters the various environments such as acidic environment (low pH). To overcome such factors, Salmonella has certain adaptable mechanisms. In present 'study total 200 samples of tomatoes were analyzed out of which 10 samples were found to contain Salmonella. All the 10 isolates were then subjected to the antibiotic susceptibility testing and were found to be resistant against several antibiotics. These were subjected to acid resistant tolerance study.

  4. Anaerobic thermophiles.

    Science.gov (United States)

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

    The term "extremophile" was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of "extreme" environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally "hot environments" on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong to the Archaea has definitely

  5. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  6. Ameliorative effects of polyunsaturated fatty acids against palmitic acid-induced insulin resistance in L6 skeletal muscle cells

    Directory of Open Access Journals (Sweden)

    Sawada Keisuke

    2012-03-01

    Full Text Available Abstract Background Fatty acid-induced insulin resistance and impaired glucose uptake activity in muscle cells are fundamental events in the development of type 2 diabetes and hyperglycemia. There is an increasing demand for compounds including drugs and functional foods that can prevent myocellular insulin resistance. Methods In this study, we established a high-throughput assay to screen for compounds that can improve myocellular insulin resistance, which was based on a previously reported non-radioisotope 2-deoxyglucose (2DG uptake assay. Insulin-resistant muscle cells were prepared by treating rat L6 skeletal muscle cells with 750 μM palmitic acid for 14 h. Using the established assay, the impacts of several fatty acids on myocellular insulin resistance were determined. Results In normal L6 cells, treatment with saturated palmitic or stearic acid alone decreased 2DG uptake, whereas unsaturated fatty acids did not. Moreover, co-treatment with oleic acid canceled the palmitic acid-induced decrease in 2DG uptake activity. Using the developed assay with palmitic acid-induced insulin-resistant L6 cells, we determined the effects of other unsaturated fatty acids. We found that arachidonic, eicosapentaenoic and docosahexaenoic acids improved palmitic acid-decreased 2DG uptake at lower concentrations than the other unsaturated fatty acids, including oleic acid, as 10 μM arachidonic acid showed similar effects to 750 μM oleic acid. Conclusions We have found that polyunsaturated fatty acids, in particular arachidonic and eicosapentaenoic acids prevent palmitic acid-induced myocellular insulin resistance.

  7. Development of acid-resistant HEPA filter components

    International Nuclear Information System (INIS)

    Laboratory and in-service tests of various HEPA filter media and separators were conducted to establish their relative resistances to HNO3-HF vapors. Filter medium of glass fiber with Nomex additive and aluminum separators with an epoxy-vinyl coating have performed quite well in the acid environment in the laboratory, and in prototype-filters placed in service in a plenum at Rocky Flats. Proprietary filters with new design and/or components were also tested in service with generally good results

  8. Effect of Omega-3 Fatty Acids Treatment on Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Mogoş Tiberius

    2014-12-01

    Full Text Available Background and aims: Insulin resistance (IR is a common pathogenic factor of several diseases: diabetes mellitus, the metabolic syndrome, arterial hypertension, atherosclerosis, dyslipidemia, etc. There are many therapeutic factors involved in decreasing IR. Among them we mention metformin, pioglitazone, physical activity, weight loss, diet, etc. In the last decade, there are more observations of the influence of polyunsaturated fatty acids on IR. The most powerful seem to be omega-3 fatty acids. In our study, we wanted to asses if the administration of omega-3 fatty acids is involved in modifying IR. Materials and methods: We evaluated 126 diabetic patients with IR from January 2011 until July 2014. The study was open-label and non-randomized. For the determination of IR we used the HOMA-IR method. Results: For both males and females there was a regression of HOMA-IR during the 4 weeks of treatment with omega-3 and also after 2 weeks after stopping the administration of these fatty acids. The decrease of HOMA-IR was statistically significant (p<0.05. The statistic result observed in the next 2 weeks after stopping administration of omega-3 was also significant (p<0.05.

  9. Effects of volatile fatty acids on a thermophilic anaerobic hydrogen fermentation process degrading peptone.

    Science.gov (United States)

    Cheng, S S; Chang, S M; Chen, S T

    2002-01-01

    Hydrogen fermentation using glucose as a single substrate caused abrupt pH drops and the gradual losses of hydrogen producers, which in turn led to system failure. In this study the use of a proteinaceous substrate, peptone, avoided the abrupt pH drops in the reactive system and allowed for further exploration of volatile fatty acids (VFAs) and pH effects on the hydrogen fermentation process. Our results showed that: (1) during the hydrogen fermentation tests, the abrupt pH drops were avoided thus system stability increased due to the production of ammonia from the peptone fermented, (2) pH control was not necessary and the addition of acetate to the process had little effect on the hydrogen fermentation process, (3) at the extreme pHs the addition of acetate either lengthened the lag phase (pH hydrogen production rate (pH > or = 8), and both situations were not desired, and (4) high VFA content in the system sped up the consumption of hydrogen gas. Results of this study suggested that the hydrogen fermentation using the protein-containing substances as substrate was beneficial in maintaining the system pH. As long as the pH was maintained around 6-8, system inhibition due to VFAs accumulation was minimized. Thus, the optimal operation of a hydrogen fermentation process would be achievable via the control of substrate composition at a certain carbohydrate-to-protein ratio.

  10. Uncoupled hydrogen and volatile fatty acids generation in a two-step biotechnological anaerobic process fed with actual site wastewater.

    Science.gov (United States)

    Monti, Matilde; Scoma, Alberto; Martinez, Gonzalo; Bertin, Lorenzo; Fava, Fabio

    2015-05-25

    Among agro-wastes, olive mill wastewater (OMW) truly qualifies as a high impact organic residue due to its biochemical-rich composition and high annual production. In the present investigation, dephenolized OMW (OMWdeph) was employed as the feedstock for a biotechnological two-stage anaerobic process dedicated to the production of biohydrogen and volatile fatty acids (VFAs), respectively. To this end, two identically configured packed-bed biofilm reactors were operated sequentially. In the first, the hydraulic retention time was set to 1 day, whereas in the second it was equal to 5 days. The rationale was to decouple the hydrolysis of the organic macronutrients held by the OMWdeph, so as to quantitatively generate a biogas enriched in H2 (first stage aim), for the acidogenesis of the residual components left after hydrolysis, to then produce a highly concentrated mixture of VFAs (second stage aim). Results showed that the generation of H2 and VFAs was effectively split, with carbohydrates and lipids, respectively, being the main substrates of the two processes. About 250 ml H2 L(-1) day(-1) was produced, corresponding to a yield of 0.36 mol mol(-1) of consumed carbohydrates (expressed as glucose equivalents). The overall concentration of VFAs in the acidogenic process was 13.80 g COD L(-1), so that 2.76 g COD L(-1) day(-1) was obtained. Second generation biorefineries use a selected fraction of an organic waste to conduct a microbiologically-driven pathway towards the generation of one target molecule. With the proposed approach, a greater value of the waste was attained, since the multi-purpose two-stage process did not entail competition for substrates between the first and the second steps. PMID:25174889

  11. Removing volatile fatty acids during the anaerobic treatment of pig sewage; Remocion de acidos grasos volatiles durante el tratamiento anaerobio de aguas residuales porcicolas

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Mendez Novelo, R.; Magana Pietra, A.; Partinez Pereda, P.; Fernandez Villagomez, G. [Facultad de Ingenieria, Universidad Atuonoma de Yucatan. Mexico (Mexico)

    1997-06-01

    This study examined the behaviour of a hybrid anaerobic digester in treating pig farm sewage. The experimental model consisted of a 208-litre UASB reactor at the bottom and a 195-litre high-rate sedimentator at the top. The digester was installed on a pig farm and its efficiency in removing volatile (acetic and propionic) fatty acids (VFA) was determined with hydraulic retention time (HTR) as the critical parameter for evaluating the anaerobic system`s performance. The results obtained with the five different HRTs used during the experiment are reported. The highest removal rates were obtained with an HRT of 2.8 days: 98% in the UASB, 28% in the sedimentator and 98% in the digester as a whole. An HRT of 1 day gave VFA removal rates of 40%, 12% and 50% in the UASB reactor sedimentator and digest respectively. (Author) 16 refs.

  12. Long-chain fatty acids inhibition and adaptation process in anaerobic thermophilic digestion: Batch tests, microbial community structure and mathematical modelling

    DEFF Research Database (Denmark)

    Paltsi, Jordi; Illa, J.; Prenafeta-Boldu, F.X.;

    2010-01-01

    . Population profiles of eubacterial and archaeal 16S rDNA genes revealed that no significant shift on microbial community composition took place upon biomass exposure to LCFA. DNA sequencing of predominant DGGE bands showed close phylogenetic affinity to ribotypes characteristic from specific beta......Biomass samples taken during the continuous operation of thermophilic anaerobic digestors fed with manure and exposed to successive inhibitory pulses of long-chain fatty acids (LCFA) were characterized in terms of specific metabolic activities and 16S rDNA DGGE profiling of the microbial community...... structure. Improvement of hydrogenotrophic and acidogenic (beta-oxidation) activity rates was detected upon successive LCFA pulses, while different inhibition effects over specific anaerobic trophic groups were observed. Bioreactor recovery capacity and biomass adaptation to LCFA inhibition were verified...

  13. Use of anaerobic green fluorescent protein versus green fluorescent protein as reporter in lactic acid bacteria.

    Science.gov (United States)

    Landete, José M; Langa, Susana; Revilla, Concepción; Margolles, Abelardo; Medina, Margarita; Arqués, Juan L

    2015-08-01

    Lactic acid bacteria (LAB) are commonly used in the production of fermented and probiotic foods. Development of molecular tools to discriminate the strains of interest from the endogenous microbiota in complex environments like food or gut is of high interest. Green fluorescent protein (GFP)-like chromophores strictly requires molecular oxygen for maturation of fluorescence, which restrict the study of microorganisms in low-oxygen environments. In this work, we have developed a noninvasive cyan-green fluorescent based reporter system for real-time tracking of LAB that is functional under anoxic conditions. The evoglow-Pp1 was cloned downstream from the promoters D-alanyl-D-alanine carboxypeptidase and elongation factor Tu of Lactobacillus reuteri CECT925 using pNZ8048 and downstream of the lactococcal P1 promoter using pT1NX. The classical gfp was also cloned in pT1NX. These recombinant expression vectors were electroporated into Lactococccus, Lactobacillus, and Enterococcus strains with biotechnological and/or probiotic interests to assess and compare their functionality under different conditions of oxygen and pH. The expression was analyzed by imaging and fluorometric methods as well as by flow cytometry. We demonstrate that reporter systems pNZ:TuR-aFP and pT1-aFP are two versatile molecular markers for monitoring LAB in food and fecal environments without the potential problems caused by oxygen and pH limitations, which could be exploited for in vivo studies. Production of the fluorescent protein did not disturb any important physiological properties of the parental strains, such as growth rate, reuterin, or bacteriocin production. PMID:26129953

  14. In-vitro susceptibility of multiple drug resistant Pseudomonas aeruginosa to organic acids

    Directory of Open Access Journals (Sweden)

    Basavraj S. Nagoba

    2013-06-01

    Full Text Available Objectives: Pseudomonas aeruginosa is a classic opportunistic pathogen with innate resistance to many antibiotics anddisinfectants. Resistance to antimicrobial agents makes it the most noxious organism to eliminate from infection site. Inview of its antimicrobial resistance, an attempt was made to study its susceptibility to various organic acids.Methods: Seven clinical isolates of P. aeruginosa resistant to multiple antibiotics were subjected to in vitro susceptibilityto various organic acids by broth dilution method to find out susceptibility to various organic acids.Results: The isolates of P. aeruginosa resistant to 14 antimicrobials were found susceptible to one percent oxalic acidand trichloroacetic acid, two percent lactic acid and citric acid, and three percent acetic acid. It is interesting to note thatstrains resistant to multiple antibiotics were also found susceptible to organic acids. Oxalic acid and trichloroacetic acidwere found highly effective.Conclusions: Clinical use of oxalic acid, trichloroacetic acid and lactic acid as topical agents to treat superficial pseudomonalinfections caused by difficult strains of P. aeruginosa may be recommended after confirmation of their toxicityand in vivo efficacy in animal models. J Microbiol Infect Dis 2013; 3(2: 67-70Key words: Pseudomonas aeruginosa, Multiple Antibiotic Resistance, Susceptibility to Organic Acids

  15. Silylated Acid Hardened Resist [SAHR] Technology: Positive, Dry Developable Deep UV Resists

    Science.gov (United States)

    Thackeray, James W.; Bohland, John F.; Pavelchek, , Edward K.; Orsula, George W.; McCullough, Andrew W.; Jones, Susan K.; Bobbio, Stephen M.

    1990-01-01

    This paper describes continuing efforts in the development of Acid Hardened Resist (AHR) systems for use in deep UV photolithography. The Silylated AHR (SAHR) process treats a highly absorbing resist, such as XP-8928, with trimethylsilyldiethylamine. The exposed, crosslinked areas show virtually no reactivity with the silylating agent, and the unexposed areas incorporate 10 to 12% by weight silicon in the film. The silicon appears to incorporate from the exterior in a constant concentration, consistent with Case II diffusion. Subsequent dry etching leads to a positive tone image. The contrast is 5, and the photospeed is ~10 mJ/cm2. Resolution of 0.5 μm line/space pairs has been demonstrated, although substantial proximity effects are encountered.

  16. Influence of Wall Teichoic Acid on Lysozyme Resistance in Staphylococcus aureus▿

    OpenAIRE

    Bera, Agnieszka; Biswas, Raja; Herbert, Silvia; Kulauzovic, Emir; Weidenmaier, Christopher; Peschel, Andreas; Götz, Friedrich

    2006-01-01

    Staphylococcus aureus peptidoglycan (PG) is completely resistant to the hydrolytic activity of lysozyme. Here we show that modifications in PG by O acetylation, wall teichoic acid, and a high degree of cross-linking contribute to this resistance.

  17. Arabidopsis YAK1 regulates abscisic acid response and drought resistance.

    Science.gov (United States)

    Kim, Dongjin; Ntui, Valentine Otang; Xiong, Liming

    2016-07-01

    Abscisic acid (ABA) is an important phytohormone that controls several plant processes such as seed germination, seedling growth, and abiotic stress response. Here, we report that AtYak1 plays an important role in ABA signaling and postgermination growth in Arabidopsis. AtYak1 knockout mutant plants were hyposensitive to ABA inhibition of seed germination, cotyledon greening, seedling growth, and stomatal movement. atyak1-1 mutant plants display reduced drought stress resistance, as evidenced by water loss rate and survival rate. Molecular genetic analysis revealed that AtYak1 deficiency led to elevated expression of stomatal-related gene, MYB60, and down-regulation of several stress-responsive genes. Altogether, these results indicate that AtYak1 plays a role as a positive regulator in ABA-mediated drought response in Arabidopsis. PMID:27264339

  18. Helicobacter pylori's cholesterol uptake impacts resistance to docosahexaenoic acid.

    Science.gov (United States)

    Correia, Marta; Casal, Susana; Vinagre, João; Seruca, Raquel; Figueiredo, Ceu; Touati, Eliette; Machado, José C

    2014-05-01

    Helicobacter pylori colonizes half of the world population and is associated with gastric cancer. We have previously demonstrated that docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid known for its anti-inflammatory and antitumor effects, directly inhibits H. pylori growth in vitro and in mice. Nevertheless, the concentration of DHA shown to reduce H. pylori mice gastric colonization was ineffective in vitro. Related to the auxotrophy of H. pylori for cholesterol, we hypothesize that other mechanisms, in addition to DHA direct antibacterial effect, must be responsible for the reduction of the infection burden. In the present study we investigated if DHA affects also H. pylori growth, by reducing the availability of membrane cholesterol in the epithelial cell for H. pylori uptake. Levels of cholesterol in gastric epithelial cells and of cholesteryl glucosides in H. pylori were determined by thin layer chromatography and gas chromatography. The consequences of epithelial cells' cholesterol depletion on H. pylori growth were assessed in liquid cultures. We show that H. pylori uptakes cholesterol from epithelial cells. In addition, DHA lowers cholesterol levels in epithelial cells, decreases its de novo synthesis, leading to a lower synthesis of cholesteryl glucosides by H. pylori. A previous exposition of H. pylori to cholesterol influences the bacterium response to the direct inhibitory effect of DHA. Overall, our results suggest that a direct effect of DHA on H. pylori survival is modulated by its access to epithelial cell cholesterol, supporting the notion that cholesterol enhances the resistance of H. pylori. The cholesterol-dependent resistance of H. pylori to antimicrobial compounds raises new important aspects for the development of new anti-bacterial strategies. PMID:24447914

  19. Monomeric tartrate resistant acid phosphatase induces insulin sensitive obesity.

    Directory of Open Access Journals (Sweden)

    Pernilla Lång

    Full Text Available BACKGROUND: Obesity is associated with macrophage infiltration of adipose tissue, which may link adipose inflammation to insulin resistance. However, the impact of inflammatory cells in the pathophysiology of obesity remains unclear. Tartrate resistant acid phosphatase (TRAP is an enzyme expressed by subsets of macrophages and osteoclasts that exists either as an enzymatically inactive monomer or as an active, proteolytically processed dimer. PRINCIPAL FINDINGS: Using mice over expressing TRAP, we show that over-expression of monomeric, but not the dimeric form in adipose tissue leads to early onset spontaneous hyperplastic obesity i.e. many small fat cells. In vitro, recombinant monomeric, but not proteolytically processed TRAP induced proliferation and differentiation of mouse and human adipocyte precursor cells. In humans, monomeric TRAP was highly expressed in the adipose tissue of obese individuals. In both the mouse model and in the obese humans the source of TRAP in adipose tissue was macrophages. In addition, the obese TRAP over expressing mice exhibited signs of a low-grade inflammatory reaction in adipose tissue without evidence of abnormal adipocyte lipolysis, lipogenesis or insulin sensitivity. CONCLUSION: Monomeric TRAP, most likely secreted from adipose tissue macrophages, induces hyperplastic obesity with normal adipocyte lipid metabolism and insulin sensitivity.

  20. Improved Succinic Acid Production in the Anaerobic Culture of an Escherichia coli pflB ldhA Double Mutant as a Result of Enhanced Anaplerotic Activities in the Preceding Aerobic Culture▿

    OpenAIRE

    Wu, Hui; Li, Zhi-Min; Zhou, Li; Ye, Qin

    2007-01-01

    Escherichia coli NZN111 is a pflB ldhA double mutant which loses its ability to ferment glucose anaerobically due to redox imbalance. In this study, two-stage culture of NZN111 was carried out for succinic acid production. It was found that when NZN111 was aerobically cultured on acetate, it regained the ability to ferment glucose with succinic acid as the major product in subsequent anaerobic culture. In two-stage culture carried out in flasks, succinic acid was produced at a level of 11.26 ...

  1. Effect of polyvinyl alcohol hydrogel as a biocarrier on volatile fatty acids production of a two-stage thermophilic anaerobic membrane bioreactor.

    Science.gov (United States)

    Chaikasem, Supawat; Abeynayaka, Amila; Visvanathan, Chettiyappan

    2014-09-01

    This work studied the effect of polyvinyl alcohol hydrogel (PVA-gel) beads, as an effective biocarrier for volatile fatty acid (VFA) production in hydrolytic reactor of a two-stage thermophilic anaerobic membrane bioreactor (TAnMBR). The two-stage TAnMBR, treating synthetic high strength particulate wastewater with influent chemical oxygen demand (COD) [16.4±0.8 g/L], was operated at 55 °C. Under steady state conditions, the reactor was operated at an organic loading rate of 8.2±0.4 kg COD/m(3) d. Operational performance of the system was monitored by assessing VFA composition and quantity, methane production and COD removal efficiency. Increment of VFA production was observed with PVA-gel addition. Hydrolytic effluent contained large amount of acetic acid and n-butyric acid. However, increase in VFA production adversely affected the methanogenic reactor performance due to lack of methanogenic archaea. PMID:24803272

  2. Fatty-acid metabolism is involved in stress-resistance mechanisms of Caenorhabditis elegans

    OpenAIRE

    Horikawa, Makoto; Sakamoto, Kazuichi

    2009-01-01

    Fatty acids are the major components of the phospholipid bilayer and are involved in several functions of cell membrane. We previously reported that fatty-acid metabolism is involved in the regulation of DAF-2/insulin signal in Caenorhabditis elegans. In this study, we investigate the role of fatty-acid metabolism in stress resistance with respect to daf-16 in nematode. We found that fatty-acid metabolism regulates heat, osmotic, and oxidative-stress resistance in C. elegans. RNA interference...

  3. Toxicity in anaerobic digestion with emphasis on the effect of ammonia, sulfide and long-chain fatty acids on methanogenesis.

    NARCIS (Netherlands)

    Koster, I.W.

    1989-01-01

    The dissertation concerns the problem of toxicity in anaerobic digestion, which to a large extent is the problem of inhibition of methanogenic conversions by chemical compounds. The dissertation begins with an extensive literature review in which the microbiology o

  4. Nonproteinogenic D-amino acids at millimolar concentrations are a toxin for anaerobic microorganisms relevant to early Earth and other anoxic planets.

    Science.gov (United States)

    Nixon, Sophie L; Cockell, Charles S

    2015-03-01

    The delivery of extraterrestrial organics to early Earth provided a potentially important source of carbon and energy for microbial life. Optically active organic compounds of extraterrestrial origin exist in racemic form, yet life on Earth has almost exclusively selected for L- over D-enantiomers of amino acids. Although D-enantiomers of proteinogenic amino acids are known to inhibit aerobic microorganisms, the role of concentrated nonproteinogenic meteoritic D-amino acids on anaerobic metabolisms relevant to early Earth and other anoxic planets such as Mars is unknown. Here, we test the inhibitory effect of D-enantiomers of two nonproteinogenic amino acids common to carbonaceous chondrites, norvaline and α-aminobutyric acid, on microbial iron reduction. Three pure strains (Geobacter bemidjiensis, Geobacter metallireducens, Geopsychrobacter electrodiphilus) and an iron-reducing enrichment culture were grown in the presence of 10 mM D-enantiomers of both amino acids. Further tests were conducted to assess the inhibitory effect of these D-amino acids at 1 and 0.1 mM. The presence of 10 mM D-norvaline and D-α-aminobutyric acid inhibited microbial iron reduction by all pure strains and the enrichment. G. bemidjiensis was not inhibited by either amino acid at 0.1 mM, but D-α-aminobutyric acid still inhibited at 1 mM. Calculations using published meteorite accumulation rates to the martian surface indicate D-α-aminobutyric acid may have reached inhibitory concentrations in little over 1000 years during peak infall. These data show that, on a young anoxic planet, the use of one enantiomer over another may render the nonbiological enantiomer an environmental toxin. Processes that generate racemic amino acids in the environment, such as meteoritic infall or impact synthesis, would have been toxic processes and could have been a selection pressure for the evolution of early racemases. PMID:25695622

  5. A novel fast mass transfer anaerobic inner loop fluidized bed biofilm reactor for PTA wastewater treatment.

    Science.gov (United States)

    Chen, Yingwen; Zhao, Jinlong; Li, Kai; Xie, Shitao

    2016-01-01

    In this paper, a fast mass transfer anaerobic inner loop fluidized bed biofilm reactor (ILFBBR) was developed to improve purified terephthalic acid (PTA) wastewater treatment. The emphasis of this study was on the start-up mode of the anaerobic ILFBBR, the hydraulic loadings and the operation stability. The biological morphology of the anaerobic biofilm in the reactors was also analyzed. The anaerobic column could operate successfully for 46 days due to the pre-aerating process. The anaerobic column had the capacity to resist shock loadings and maintained a high stable chemical oxygen demand (COD) and terephthalic acid removal rates at a hydraulic retention time of 5-10 h, even under conditions of organic volumetric loadings as high as 28.8 kg COD·m(-3).d(-1). The scanning electron microscope analysis of the anaerobic carrier demonstrated that clusters of prokaryotes grew inside of pores and that the filaments generated by pre-aeration contributed to the anaerobic biofilm formation and stability. PMID:27642828

  6. Cross-resistance among cinoxacin, ciprofloxacin, DJ-6783, enoxacin, nalidixic acid, norfloxacin, and oxolinic acid after in vitro selection of resistant populations.

    OpenAIRE

    Barry, A. L.; Jones, R N

    1984-01-01

    Six different gram-negative bacilli were serially transferred through subinhibitory concentrations of seven quinolone derivatives or related organic acids. A gradual, stepwise decrease in susceptibility was noted with all seven drugs, and the resistant cultures demonstrated a concomitant cross-resistance to the other drugs.

  7. Induced resistance by cresotic acid (3-hydroxy-4-methyl methylbenzoic acid) against wilt disease of melon and cotton

    International Nuclear Information System (INIS)

    Cresotic acid (3-hydroxy-4-methylbenzoic acid) was proved be active in controlling wilt diseases of melon and cotton plants grown in the house. Soil drench with 200-1000 ppm cresotic acid induced 62-77 %, 69-79 % and 50-60 % protection against Fusarium oxysporum f.sp melonis (FOM) in melon, Fusarium oxysporum f.sp vasinfectum (FOV) and Verticillium dahliae in cotton, respectively. Since no inhibitory effect of cresotic acid on mycelial growth of these three fungual pathogens was observed in vitro, it is suggested that control of these wilt diseases with cresotic acid resulted from induced resistance. Cresotic acid induced resistance in melon plants not only against race 0, race 1, race 2 and race 1,2, but also against a mixture of these four races of FOM, suggesting a non-race- specific resistance. Level of induced resistance by cresotic acid against FOM depended on inoculum pressure applied to melon plants. At 25 day after inoculation with FOM, percentage protection induced by cresotic acid under low inoculum pressure retained a level of 51 %, while under high inoculum pressure percentage protection decreased to only 10 %. High concentrations of cresotic acid significantly reduced plant growth. Reduction in fresh weight of melon (36-51%) and cotton (42-71%) was obtained with 500-1000 ppm cresotic acid, while only less than 8% reduction occurred with 100-200 ppm. (author)

  8. Anaerobic Process.

    Science.gov (United States)

    Yang, Qian; Ju, Mei-Ting; Li, Wei-Zun; Liu, Le; Wang, Yan-Nan; Chang, Chein-Chi

    2016-10-01

    A review of the literature published in 2015 on the focus of Anaerobic Process. It is divided into the following sections. Pretreatment Organic waste Multiple-stage co-digestion Process Methodology and Technology. PMID:27620085

  9. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  10. Fusidic acid resistance in Staphylococcus aureus nasal carriage strains in nine European countries.

    NARCIS (Netherlands)

    Heijer, C.D.J. den; Bijnen, E.M.E. van; Paget, W.J.; Stobberingh, E.E.

    2014-01-01

    Aim: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. Materials & methods: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by

  11. Fusidic acid resistance in Staphylococcus aureus nasal carriage strains in nine European countries

    NARCIS (Netherlands)

    Heijer, C.D. den; Bijnen, E.M. van; Paget, W.J.; Stobberingh, E.E.

    2014-01-01

    AIM: To evaluate fusidic acid resistance pheno- and geno-typically in nasal carriage Staphylococcus aureus isolated from general practice patients in nine European countries. MATERIALS & METHODS: Phenotypic fusidic acid resistance was determined by disc diffusion and MIC values, and genotypically by

  12. Slagment Cement Improve the Cement Resistance Toward Acids Attack During Acidizing Treatment

    Directory of Open Access Journals (Sweden)

    Nik Khairul Irfan Bin Nik Ab. Lah.

    2013-05-01

    Full Text Available Acidizing treatment in past experience shows several zonal isolation problems after the treatment. This study presents the effect of the acid treatment toward class G cement and slagment cement as the improvement method to improve the cement resistance toward the acid. Lab experiments were conducted by immerge the respective cement cubes into 12% HCl/3% HF solution for 40 min before several analysis were conducted. Based on the result, the mass loss and compressive strength loss of the cement cubes decrease as the curing temperature and pressure increase due to more evenly distributed cement chemical composition crystal in high curing condition as shown in Scanning Electron Microscopy (SEM analysis. From X-Ray Diffraction (XRD and X-Ray Fluorescence (XRF analysis, only the first layer of the cement cubes shows chemical component change due to the reaction between the acid. This study found that, replacing class G cement to slagment cement can reduce the mass loss and compressive strength loss up to 72% and 82%, respectively.

  13. Retinoic acid receptor alpha is associated with tamoxifen resistance in breast cancer

    OpenAIRE

    Johansson, Henrik J; Sanchez, Betzabe C.; Mundt, Filip; Forshed, Jenny; Kovacs, Aniko; Panizza, Elena; Hultin-Rosenberg, Lina; Lundgren, Bo; Martens, Ulf; Máthé, Gyöngyvér; Yakhini, Zohar; Helou, Khalil; Krawiec, Kamilla; Kanter, Lena; Hjerpe, Anders

    2013-01-01

    About one-third of oestrogen receptor alpha-positive breast cancer patients treated with tamoxifen relapse. Here we identify the nuclear receptor retinoic acid receptor alpha as a marker of tamoxifen resistance. Using quantitative mass spectrometry-based proteomics, we show that retinoic acid receptor alpha protein networks and levels differ in a tamoxifen-sensitive (MCF7) and a tamoxifen-resistant (LCC2) cell line. High intratumoural retinoic acid receptor alpha protein levels also correlate...

  14. Resistance to ursodeoxycholic acid-induced growth arrest can also result in resistance to deoxycholic acid-induced apoptosis and increased tumorgenicity

    International Nuclear Information System (INIS)

    There is a large body of evidence which suggests that bile acids increase the risk of colon cancer and act as tumor promoters, however, the mechanism(s) of bile acids mediated tumorigenesis is not clear. Previously we showed that deoxycholic acid (DCA), a tumorogenic bile acid, and ursodeoxycholic acid (UDCA), a putative chemopreventive agent, exhibited distinct biological effects, yet appeared to act on some of the same signaling molecules. The present study was carried out to determine whether there is overlap in signaling pathways activated by tumorogenic bile acid DCA and chemopreventive bile acid UDCA. To determine whether there was an overlap in activation of signaling pathways by DCA and UDCA, we mutagenized HCT116 cells and then isolated cell lines resistant to UDCA induced growth arrest. These lines were then tested for their response to DCA induced apoptosis. We found that a majority of the cell lines resistant to UDCA-induced growth arrest were also resistant to DCA-induced apoptosis, implying an overlap in DCA and UDCA mediated signaling. Moreover, the cell lines which were the most resistant to DCA-induced apoptosis also exhibited a greater capacity for anchorage independent growth. We conclude that UDCA and DCA have overlapping signaling activities and that disregulation of these pathways can lead to a more advanced neoplastic phenotype

  15. Anaerobic biological treatment

    International Nuclear Information System (INIS)

    The Enso-Fenox process has been very successfully used to remove chlorinated phenolic compounds from pulp bleaching effluents. It is a two-stage anaerobic/aerobic process consisting of a nonmethanogenic anaerobic fluidized bed followed by a trickling filter. Studies have been conducted on reductive dechlorination of chlorinated aromatic compounds under anaerobic conditions with chlorinated phenols as the sole carbon and energy source. Approximately 40% of the added chlorophenols was converted to CH4 and CO2. Substrate loading rates were 20 mg/L/d at hydraulic detention times of 2-4 days with 90% substrate conversion efficiency. Reductive dechlorination of mono, di-, tri-, and pentachlorophenols has been demonstrated in anaerobic sewage sludge. The following constituents were tested in the laboratory at their approximate concentrations in coal conversion wastewater (CCWW) and were anaerobically degraded in serum bottles: 1,000 mg/L phenol; 500 mg/L resorcinol; 1,000 mg/L benzoic acid; 500 mg/L p-cresol; 200 mg/L pyridine; 2,000 mg/L benzoic acid; 250 mg/L 40 methylcatechol; 500 mg/L 4-ethylpyridine; and 2,000 mg/L hexanoic acid. A petrochemical may initially exhibit toxicity to an unacclimated population of methane-fermenting bacteria, but with acclimation the toxicity may be greatly reduced or disappear. In addition, the microorganisms may develop the capacity to actually degrade compounds which showed initial toxicity. Since biomass digestion requires a complete consortium of bacteria, it is relevant to study the effect of a given process as well as to individual steps within the process. A toxicant can inhibit the rate-limiting step and/or change the step that is rate-limiting. Both manifestations of toxicity can severely affect the overall process

  16. Effect of calcium chloride on abating inhibition due to volatile fatty acids during the start-up period in anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Kumar, Sunil; Das, Avijit; Srinivas, G Lohit Kumar; Dhar, Hiya; Ojha, Vivek Kumar; Wong, Jonathan

    2016-01-01

    Biomethanation of municipal solid waste (MSW) is a slow process and the yield of biogas is usually low. The present study was carried out to examine the effect of calcium chloride (CaCl2) on anaerobic digestion of MSW. Three anaerobic digesters with different concentrations of CaCl2, namely sample without additives (Control), sample with 2.5 g/L CaCl2 (R1) and sample with 5 g/L CaCl2 (R2) were studied separately and the significant results are presented. From the experimental results, it was observed that pH decreased with an increase in the dosage of CaCl2. Total solids and volatile solids reduction percentage in digester R2 was considerably lower than Control and R1 digesters. The significant positive correlation with small increments in volatile solids and chemical oxygen demand (COD) reduction were observed with an increase in pH. The cumulative biogas production in all the three digesters (Control, R1 and R2) were observed to be 35.38, 46.46 and 37.56 L, respectively. It was also observed that the volatile fatty acids (VFAs) removal efficiency in digester R1 was the best among all the three digesters. A comparison of the effluent characteristics revealed improvement in the overall performance of the digester R1 amended with 2.5 g/L CaCl2 over the other two digesters. PMID:26609893

  17. Exploring the in vitro formation of trimethylarsine sulfide from dimethylthioarsinic acid in anaerobic microflora of mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS

    International Nuclear Information System (INIS)

    Although metabolism of arsenicals to form methylated oxoarsenical species has been extensively studied, less is known about the formation of thiolated arsenical species that have recently been detected as urinary metabolites. Indeed, their presence suggests that the metabolism of ingested arsenic is more complex than previously thought. Recent reports have shown that thiolated arsenicals can be produced by the anaerobic microflora of the mouse cecum, suggesting that metabolism prior to systemic absorption may be a significant determinant of the pattern and extent of exposure to various arsenic-containing species. Here, we examined the metabolism of 34S labeled dimethylthioarsinic acid (34S-DMTAV) by the anaerobic microflora of the mouse cecum using HPLC-ICP-MS and HPLC-ESI-MS/MS to monitor for the presence of various oxo- and thioarsenicals. The use of isotopically enriched 34S-DMTAV made it possible to differentiate among potential metabolic pathways for production of the trimethylarsine sulfide (TMASV). Upon in vitro incubation in an assay containing anaerobic microflora of mouse cecum, 34S-DMTAV underwent several transformations. Labile 34S was exchanged with more abundant 32S to produce 32S-DMTAV, a thiol group was added to yield DMDTAV, and a methyl group was added to yield 34S-TMASV. Because incubation of 34S-DMTAV resulted in the formation of 34S-TMASV, the pathway for its formation must preserve the arsenic-sulfur bond. The alternative metabolic pathway postulated for formation of TMASV from dimethylarsinic acid (DMAV) would proceed via a dimethylarsinous acid (DMAIII) intermediate and would necessitate the loss of 34S label. Structural confirmation of the metabolic product was achieved using HPLC-ESI-MS/MS. The data presented support the direct methylation of DMTAV to TMASV. Additionally, the detection of isotopically pure 34S-TMASV raises questions about the sulfur exchange properties of TMASV in the cecum material. Therefore, 34S-TMASV was incubated and

  18. Ferulic acid reverses ABCB1-mediated paclitaxel resistance in MDR cell lines.

    Science.gov (United States)

    Muthusamy, Ganesan; Balupillai, Agilan; Ramasamy, Karthikeyan; Shanmugam, Mohana; Gunaseelan, Srithar; Mary, Beaulah; Prasad, N Rajendra

    2016-09-01

    Multidrug resistance (MDR) remains a major obstacle in cancer chemotherapy. The use of the dietary phytochemicals as chemosensitizing agents to enhance the efficacy of conventional cytostatic drugs has recently gained the attention as a plausible approach for overcoming the drug resistance. The aim of this study was to investigate whether a naturally occurring diet-based phenolic acid, ferulic acid, could sensitize paclitaxel efficacy in ABCB1 overexpressing (P-glycoprotein) colchicine selected KB Ch(R)8-5 cell line. In vitro drug efflux assays demonstrated that ferulic acid inhibits P-glycoprotein transport function in drug resistant KB Ch(R)8-5 cell lines. However, ferulic acid significantly downregulates ABCB1 expression in a concentration dependent manner. Cytotoxicity assay reveals that ferulic acid decreased paclitaxel resistance in KBCh(R)8-5 and HEK293/ABCB1 cells, which indicates its chemosensitizing potential. Clonogenic cell survival assay and apoptotic morphological staining further confirm the chemosensitizing potential of ferulic acid in drug resistant KB Ch(R)8-5 cell lines. Ferulic acid treatment enhances paclitaxel mediated cell cycle arrest and upregulates paclitaxel-induced apoptotic signaling in KB resistant cells. Hence, it has been concluded that downregulation of ABCB1 and subsequent induction of paclitaxel-mediated cell cycle arrest and apoptotic signaling may be the cause for the chemosensitizing potential of ferulic acid in P-gp overexpressing cell lines. PMID:27262378

  19. Fluoroquinolone Resistance in Anaerobic Bacteria following Exposure to Levofloxacin, Trovafloxacin, and Sparfloxacin in an In Vitro Pharmacodynamic Model

    OpenAIRE

    Ross, Gigi H.; Wright, David H.; Hovde, Laurie Baeker; Peterson, Marnie L.; Rotschafer, John C.

    2001-01-01

    This investigation explored pharmacodynamic characteristics of fluoroquinolones against Bacteroides thetaiotamicron and the potential for development of resistance. An in vitro model was used to generate kill curves with three fluoroquinolones at various area under the concentration-time curve (AUC)/MIC ratios. Concentration-independent killing was observed. Increases in MICs were noted following exposure to fluoroquinolones at AUC/MIC ratios of 6 to 14.

  20. Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males

    Directory of Open Access Journals (Sweden)

    Orem Ihsan

    2009-04-01

    Full Text Available Abstract Background Recent research has indicated that short term administration of glycine propionyl-L-carnitine (GPLC significantly elevates levels of nitric oxide metabolites at rest and in response to reactive hyperaemia. However, no scientific evidence exists that suggests such supplementation enhances exercise performance in healthy, trained individuals. The purpose of this study was to examine the effects of GPLC on the performance of repeated high intensity stationary cycle sprints with limited recovery periods in resistance trained male subjects. Methods In a double-blind, placebo-controlled, cross-over design, twenty-four male resistance trained subjects (25.2 ± 3.6 years participated in two test sessions separated by one week. Testing was performed 90 minutes following oral ingestion of either 4.5 grams GPLC or 4.5 grams cellulose (PL, in randomized order. The exercise testing protocol consisted of five 10-second Wingate cycle sprints separated by 1-minute active recovery periods. Peak (PP and mean values (MP of sprint power output and percent decrement of power (DEC were determined per bout and standardized relative to body masss. Heart rate (HR and blood lactate (LAC were measured prior to, during and following the five sprint bouts. Results Significant main effects (p Conclusion These findings indicate that short-term oral supplementation of GPLC can enhance peak power production in resistance trained males with significantly less LAC accumulation.

  1. Effects of arachidonic acid supplementation on training adaptations in resistance-trained males

    Directory of Open Access Journals (Sweden)

    Greenwood Mike

    2007-11-01

    Full Text Available Abstract Background To determine the impact of AA supplementation during resistance training on body composition, training adaptations, and markers of muscle hypertrophy in resistance-trained males. Methods In a randomized and double blind manner, 31 resistance-trained male subjects (22.1 ± 5.0 years, 180 ± 0.1 cm, 86.1 ± 13.0 kg, 18.1 ± 6.4% body fat ingested either a placebo (PLA: 1 g·day-1 corn oil, n = 16 or AA (AA: 1 g·day-1 AA, n = 15 while participating in a standardized 4 day·week-1 resistance training regimen. Fasting blood samples, body composition, bench press one-repetition maximum (1RM, leg press 1RM and Wingate anaerobic capacity sprint tests were completed after 0, 25, and 50 days of supplementation. Percutaneous muscle biopsies were taken from the vastus lateralis on days 0 and 50. Results Wingate relative peak power was significantly greater after 50 days of supplementation while the inflammatory cytokine IL-6 was significantly lower after 25 days of supplementation in the AA group. PGE2 levels tended to be greater in the AA group. However, no statistically significant differences were observed between groups in body composition, strength, anabolic and catabolic hormones, or markers of muscle hypertrophy (i.e. total protein content or MHC type I, IIa, and IIx protein content and other intramuscular markers (i.e. FP and EP3 receptor density or MHC type I, IIa, and IIx mRNA expression. Conclusion AA supplementation during resistance-training may enhance anaerobic capacity and lessen the inflammatory response to training. However, AA supplementation did not promote statistically greater gains in strength, muscle mass, or influence markers of muscle hypertrophy.

  2. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  3. L-glutamine provides acid resistance for Escherichia coli through enzymatic release of ammonia

    Institute of Scientific and Technical Information of China (English)

    Peilong Lu; Dan Ma; Yuling Chen; Yingying Guo; Guo-Qiang Chen; Haiteng Deng; Yigong Shi

    2013-01-01

    Bacteria,exemplified by enteropathogenic Escherichia coli (E.coli),,rely on elaborate acid resistance systems to survive acidic environment (such as the stomach).Comprehensive understanding of bacterial acid resistance is important for prevention and clinical treatment.In this study,we report a previously uncharacterized type of acid resistance system in E.coli that relies on L-glutamine (Gln),one of the most abundant food-borne free amino acids.Upon uptake into E.coli,Gln is converted to L-glutamate (Glu) by the acid-activated glutaminase YbaS,with concomitant release of gaseous ammonia.The free ammonia neutralizes proton,resulting in elevated intracellular pH under acidic environment.We show that YbaS and the amino acid antiporter GadC,which exchanges extracellular Gln with intracellular Glu,together constitute an acid resistance system that is sufficient for E.coli survival under extremely acidic environment.

  4. Inactivation of fatty acid transport protein 1 prevents fat-induced insulin resistance in skeletal muscle

    OpenAIRE

    Jason K Kim; Gimeno, Ruth E.; Higashimori, Takamasa; Kim, Hyo-Jeong; Choi, Hyejeong; Punreddy, Sandhya; Mozell, Robin L.; TAN, GUO; Stricker-Krongrad, Alain; Hirsch, David J.; Fillmore, Jonathan J.; Liu, Zhen-Xiang; Dong, Jianying; Cline, Gary; Stahl, Andreas

    2004-01-01

    Insulin resistance in skeletal muscle plays a major role in the development of type 2 diabetes and may be causally associated with increases in intramuscular fatty acid metabolites. Fatty acid transport protein 1 (FATP1) is an acyl-CoA synthetase highly expressed in skeletal muscle and modulates fatty acid uptake and metabolism by converting fatty acids into fatty acyl-CoA. To investigate the role of FATP1 in glucose homeostasis and in the pathogenesis of insulin resistance, we examined the e...

  5. Heavy metals removal from acid mine drainage water using biogenic hydrogen sulphide and effluent from anaerobic treatment: Effect of pH

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Rodriguez, A.M. [Departamento de Sistemas Fisicos, Quimicos y Naturales, Facultad de Ciencias Ambientales, Universidad Pablo de Olavide. Carretera de Utrera, km 1. 41013 Sevilla (Spain); Duran-Barrantes, M.M. [Departamento de Ingenieria Quimica, Facultad de Quimica, Universidad de Sevilla, C/Profesor Garcia Gonzalez, s/n, 41071 Sevilla (Spain); Borja, R., E-mail: rborja@cica.es [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de la Grasa, Avda. Padre Garcia Tejero 4, 41012 Sevilla (Spain); Sanchez, E.; Colmenarejo, M.F. [Consejo Superior de Investigaciones Cientificas (CSIC), Centro de Ciencias Medioambientales, C/Serrano, 115-duplicado, 28006 Madrid (Spain); Raposo, F. [Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de la Grasa, Avda. Padre Garcia Tejero 4, 41012 Sevilla (Spain)

    2009-06-15

    Four alternatives (runs A, B, C and D) for heavy metals removal (Fe, Cu, Zn and Al) from acid mine drainage water (AMDW) produced in the mining areas of the Huelva Province, Spain, were evaluated. In run A, the anaerobic effluent from the treatment of acid mine drainage water (cheese whey added as a source of carbon) was mixed with the raw AMDW. The pH increased to 3.5 with the addition of KOH. In run B, biogas with around 30% of hydrogen sulphide obtained in the anaerobic reactor was sparged to the mixture obtained in run A, but in this case at a pH of 5.5. In run C, the pH of the raw AMDW was increased to 3.5 by the addition of KOH solution. Finally, in run D, the pH of the raw AMDW was increased to 5.5 by the addition of KOH solution and further biogas was sparged under the same conditions as in run A. It was found that heavy metal removal was a function of pH. At a pH of 3.5 most of the iron was removed while Zn and Cu were partially removed. At a pH of 5.5 the removal of all metals increased considerably. The best results were obtained in run B where the percentages of removal of Fe, Cu, Zn and Al achieved values of 91.3, 96.1, 79.0 and 99.0%, respectively. According to the experimental results obtained tentative schemas of the flow diagram of the processes were proposed.

  6. The effect of acidic pH and presence of metals as parameters in establishing a sulfidogenic process in anaerobic reactor.

    Science.gov (United States)

    Vieira, Bárbara F; Couto, Pâmela T; Sancinetti, Giselle P; Klein, Bernhard; van Zyl, Dirk; Rodriguez, Renata P

    2016-08-23

    The successful use of anaerobic reactors for bioremediation of acid mine drainage has been shown in systems with neutral pH. However, the choice of an efficient and suitable process for such wastewater must consider the capability of operating at acidic pH and in the presence of metals. This work studies the performance of an anaerobic batch reactor, under conditions of varying initial pH for its efficiencies in sulfate removal and metal precipitation from synthetic acid mine drainage. The chemical oxygen demand/sulfate (COD/SO4(2-)) ratio used was 1.00, with ethanol chosen as the only energy and carbon source. The initial pH of the synthetic drainage was progressively set from 7.0 to 4.0 to make it as close as possible to that of real acid mine drainage. Metals were also added starting with iron, zinc, and finally copper. The effectiveness of sulfate and COD removal from the synthetic acid mine drainage increased as the initial pH was reduced. The sulfate removal increased from 38.5 ± 3.7% to 52.2 ± 3%, while the removal of organic matter started at 91.7 ± 2.4% and ended at 99 ± 1%. These results indicate that the sulfate reducing bacteria (SRB) community adapted to lower pH values. The metal removal observed was 88 ± 7% for iron, 98.0 ± 0.5% for zinc and 99 ± 1% for copper. At this stage, an increase in the sulfate removal was observed, which reaches up to 82.2 ± 5.8%. The kinetic parameters for sulfate removal were 0.22 ± 0.04 h(-1) with Fe, 0.26 ± 0.04 h(-1) with Fe and Zn and 0.44 ± 0.04 h(-1) with Fe, Zn, and Cu. PMID:27222283

  7. Effects of organic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.;

    2010-01-01

    mu m of the contaminated surface was required to reach corrosion rates less than 1 mm/year in salt spray condition. Among the three organic acids examined, acetic acid is the best choice. Oxalic acid can be an alternative while citric acid is not suitable for cleaning AZ31 sheet, because......Organic acids were used to clean AZ31 magnesium alloy sheet and the effect of the cleaning processes on the surface condition and corrosion performance of the alloy was investigated. Organic acid cleanings reduced the surface impurities and enhanced the corrosion resistance. Removal of at least 4...

  8. Hydrogen production from glucose by anaerobes.

    Science.gov (United States)

    Ogino, Hiroyasu; Miura, Takashi; Ishimi, Kosaku; Seki, Minoru; Yoshida, Hiroyuki

    2005-01-01

    Various anaerobes were cultivated in media containing glucose. When 100 mL of thioglycollate medium containing 2.0% (w/v) glucose was used, Clostridium butyricum ATCC 859, NBRC 3315, and NBRC 13949 evolved 227-243 mL of biogas containing about 180 mL of hydrogen in 1 day. Although some strains had some resistance against oxygen, C. butyricum ATCC 859 and 860 did not have it. C. butyricum NBRC 3315 and Enterobacter aerogenes NBRC 13534 produced hydrogen in the presence of glucose or pyruvic acid, and E. aerogenes NBRC 13534 produced hydrogen by not only glucose and pyruvic acid but also dextrin, sucrose, maltose, galactose, fructose, mannose, and mannitol. When a medium containing 0.5% (w/v) yeast extract and 2.0% (w/v) glucose was used, E. aerogenes NBRC 13534 evolved more biogas and hydrogen than C. butyricum NBRC 3315 in the absence of reducing agent.

  9. Production of bio-hydrogen by mesophilic anaerobic fermentation in an acid-phase sequencing batch reactor.

    Science.gov (United States)

    Cheong, Dae-Yeol; Hansen, Conly L; Stevens, David K

    2007-02-15

    The pH and hydraulic retention time (HRT) of an anaerobic sequencing batch reactor (ASBR) were varied to optimize the conversion of carbohydrate-rich synthetic wastewater into bio-hydrogen. A full factorial design using evolutionary operation (EVOP) was used to determine the effect of the factors and to find the optimum condition of each factor required for high hydrogen production rate. Experimental results from 20 runs indicate that a maximum hydrogen production rate of 4,460-5,540 mL/L/day under the volumetric organic loading rate (VOLR) of 75 g-COD/L/day obtained at an observed design point of HRT = 8 h and pH = 5.7. The hydrogen production rate was strongly dependent on the HRT, and the effect was statistically significant (P 0.05) was found for the pH on the hydrogen production rate. When the ASBR conditions were set for a maximum hydrogen production rate, the hydrogen production yield and specific hydrogen production rate were 60-74 mL/g-COD and 330-360 mL/g-VSS/day, respectively. The hydrogen composition was 43-51%, and no methanogenesis was observed. Acetate, propionate, butyrate, valerate, caproate, and ethanol were major liquid intermediate metabolites during runs of this ASBR. The dominant fermentative types were butyrate-acetate or ethanol-acetate, representing the typical anaerobic pathway of Clostridium species. This hydrogen-producing ASBR had a higher hydrogen production rate, compared with that produced using continuous-flow stirred tank reactors (CSTRs). This study suggests that the hydrogen-producing ASBR is a promising bio-system for prolonged and stable hydrogen production.

  10. TRANSCRIPTIONAL REGULATION OF RETINOIC ACID RECEPTOR-BETA IN RETINOIC ACID-SENSITIVE AND ACID-RESISTANT P19-EMBRYOCARCINOMA CELLS

    NARCIS (Netherlands)

    KRUYT, FAE; VANDENBRINK, CE; DEFIZE, LHK; DONATH, MJ; KASTNER, P; KRUIJER, W; CHAMBON, P; VANDERSAAG, PT; Kruyt, Frank

    1991-01-01

    As in other embryocarcinoma (EC) cell lines retinoic acid (RA) rapidly induces expression of the nuclear retinoic acid receptor (RAR) beta in murine P19 EC cells, while RAR-alpha is expressed constitutively. In the RA-resistant P19 EC-derived RAC65 cells, however, there is no such induction and an a

  11. Effect of organic loading rate on methane and volatile fatty acids productions from anaerobic treatment of palm oil mill effluent in UASB and UFAF reactors

    Directory of Open Access Journals (Sweden)

    Sumate Chaiprapat

    2007-05-01

    Full Text Available Anaerobic treatment of palm oil mill effluent (POME with the separation of the acidogenic and methanogenic phase was studied in an up-flow anaerobic sludge blanket (UASB reactor and an up-flowanaerobic filter (UFAF reactor. Furthermore, the effect of OLR on methane and volatile fatty acid productions in UASB and UFAF reactors was investigated. In this research, UASB as acidogenic reactor wasused for volatile fatty acid production and UFAF as methanogenic reactor was used for methane production. Therefore, POME without pH adjustment was used as influent for the UASB reactor. Moreover, the syntheticwastewater with pH adjustment to 6.00 was fed into the UFAF reactor. The inoculum source for both reactors was the combination of POME sludge collected from the CSTR of a POME treatment plant and granulesludge collected from the UASB reactor of a frozen sea food industry treatment plant. During experimental operation, the organic loading rate (OLR was gradually increased from 2.50 to 17.5 g COD/l/day in theUASB reactor and 1.10 to 10.0 g COD/l/day in the UFAF reactor. Consequently, hydraulic retention time (HRT ranged from 20.0 to 2.90 days in the UASB reactor and from 13.5 to 1.50 days in the UFAF reactor.The result showed that the COD removal efficiency from both reactors was greater than 60.0%. In addition, the total volatile fatty acids increased with the increasing OLR. The total volatile fatty acids and acetic acidproduction in the UASB reactor reached 5.50 g/l and 4.90 g/l, respectively at OLR of 17.5 g COD/l/day and HRT of 2.90 days before washout was observed. In the UFAF reactor, the methane and biogas productionincreased with increasing OLR until an OLR of 7.50 g COD/l/day. However, the methane and biogas production significantly decreased when OLR increased up to 10.0 g COD/l/day. Therefore, the optimum OLR inthe laboratory-scale UASB and UFAF reactors were concluded to be 15.5 and 7.50 g COD/l/day, respectively.

  12. Lactivibrio alcoholicus gen. nov., sp. nov., an anaerobic, mesophilic, lactate-, alcohol-, carbohydrate- and amino-acid-degrading bacterium in the phylum Synergistetes.

    Science.gov (United States)

    Qiu, Yan-Ling; Hanada, Satoshi; Kamagata, Yoichi; Guo, Rong-Bo; Sekiguchi, Yuji

    2014-06-01

    A mesophilic, obligately anaerobic, lactate-, alcohol-, carbohydrate- and amino-acid- degrading bacterium, designated strain 7WAY-8-7(T), was isolated from an upflow anaerobic sludge blanket reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain 7WAY-8-7(T) were motile, curved rods (0.7-1.0×5.0-8.0 µm). Spore formation was not observed. The strain grew optimally at 37 °C (range for growth was 25-40 °C) and pH 7.0 (pH 6.0-7.5), and could grow fermentatively on yeast extract, glucose, ribose, xylose, malate, tryptone, pyruvate, fumarate, Casamino acids, serine and cysteine. The main end-products of glucose fermentation were acetate and hydrogen. In co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei DSM 864(T), strain 7WAY-8-7(T) could utilize lactate, glycerol, ethanol, 1-propanol, 1-butanol, L-glutamate, alanine, leucine, isoleucine, valine, histidine, asparagine, glutamine, arginine, lysine, threonine, 2-oxoglutarate, aspartate and methionine. A Stickland reaction was not observed with some pairs of amino acids. Yeast extract was required for growth. Nitrate, sulfate, thiosulfate, elemental sulfur, sulfite and Fe (III) were not used as terminal electron acceptors. The G+C content of the genomic DNA was 61.4 mol%. 16S rRNA gene sequence analysis revealed that the isolate belongs to the uncultured environmental clone clade (called 'PD-UASB-13' in the Greengenes database) in the bacterial phylum Synergistetes, showing less than 90% sequence similarity with closely related described species such as Aminivibrio pyruvatiphilus and Aminobacterium colombiense (89.7% and 88.7%, respectively). The major cellular fatty acids were iso-C(13 : 0), iso-C(15 : 0), anteiso-C(15 : 0), C(18 : 1), C(19 : 1), C(20 : 1) and C(21 : 1). A novel genus and species, Lactivibrio alcoholicus gen. nov., sp. nov. is proposed to accommodate strain 7WAY-8-7(T) ( = JCM 17151(T

  13. Effect of folic acid on homocysteine and insulin resistance of overweight and obese children and adolescents

    Science.gov (United States)

    Dehkordi, Elham Hashemi; Sedehi, Morteza; Shahraki, Zohre Gholipour; Najafi, Reza

    2016-01-01

    Background: Considering the increasing trend of childhood obesity and subsequent burden of the disease in Iran and other countries and importance of early life intervention for achieving sustained effect on health of children and adolescents, this study aimed to investigate the effect of two different dose of folic acid on homocysteine (Hcy) level and insulin resistance of obese children. Materials and Methods: In this randomized, double-blind controlled clinical trial study, 60 obese and overweight children aged 5–12 years were enrolled. Selected obese children randomly allocated in two interventional (1 mg/day folic acid and 5 mg/day folic acid, for 8 weeks) and one control groups. Biochemical measurements including folic acid, Hcy, insulin and insulin resistance were measured between and within groups before and after trial. Results: In each group, 20 obese children were studied. The three groups were age and sex matched. After folic acid administration, mean of Hcy, insulin resistance and insulin decreased significantly in two groups which folic acid administrated with two different doses (P 0.05). Mean differences for Hcy, insulin resistance and insulin, in two intervention groups were significantly higher than the control group (P 0.05). Conclusion: The findings of current trial showed that folic acid in two studied doses could be a safe and effective supplement for obese children to reduce Hcy level and insulin resistance, which consequently could prevent obesity-related complications including cardiovascular and metabolic disorders. PMID:27274503

  14. Arginine-dependent acid-resistance pathway in Shigella boydii

    Science.gov (United States)

    Ability to survive the low pH of the human stomach is considered be an important virulent determinant. Acid tolerance of Shigella boydii 18 CDPH, the strain implicated in an outbreak may have played an important role in surviving the acidic food (bean salad). The strain was capable of inducing arg...

  15. Insulin secretion after dietary supplementation with conjugated linoleic acids and n-3 polyunsaturated fatty acids in normal and insulin-resistant mice.

    OpenAIRE

    Sörhede Winzell, Maria; Pacini, Giovanni; Ahrén, Bo

    2006-01-01

    Insulin secretion after dietary supplementation with conjugated linoleic acids and n-3 polyunsaturated fatty acids in normal and insulin-resistance mice. Am J Physiol Endocrinol Metab 290: E347-E354, 2006. First published September 27, 2005; doi:10.1152/ajpendo.00163.2005.-Conjugated linoleic acids (CLAs) and n-3 polyunsaturated fatty acids (PUFAs) improve insulin sensitivity in insulin-resistant rodents. However, the effects of these fatty acids on insulin secretion are not known but are of ...

  16. Anaerobic workout

    OpenAIRE

    McAdam, Ewan J.

    2010-01-01

    Anaerobic technology cannot directly replace current wastewater treatment processes exclusively. The UASB reactor configuration removes slightly less organic carbon by comparison as the process relies on lamella separation for passive clarification rather than using fine pores like anMBR. By contrast, whilst anMBR can operate as a single unit process for organic carbon removal, the membrane surface has to be cleaned using gas sparging to limit surface deposition, which requires extra energy. ...

  17. Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.

    Directory of Open Access Journals (Sweden)

    Zheng Gong

    Full Text Available Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

  18. Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.

    Science.gov (United States)

    Gong, Zheng; Tang, M Matt; Wu, Xueliang; Phillips, Nancy; Galkowski, Dariusz; Jarvis, Gary A; Fan, Huizhou

    2016-01-01

    Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

  19. Contact Resistance of Tantalum Coatings in Fuel Cells and Electrolyzers using Acidic Electrolytes at Elevated Temperatures

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Christensen, Erik; Barner, Jens H. Von

    2014-01-01

    Tantalum has so far been found to be the only construction material with sufficient corrosion resistance for high temperature polymer electrolyte membrane electrolyzers using acidic electrolytes above 100◦C. In this work the interfacial contact resistances of tantalum plates and tantalum coated...... stainless steel were found to be far below the US Department of Energy target value of 10mcm2. The good contact resistance of tantalum was demonstrated by simulating high temperature polymer electrolyte membrane electrolysis conditions by anodization performed in 85% phosphoric acid at 130◦C, followed...

  20. In vitro selection of rape variants resistant to oxalic acid using haploid stem apexes

    International Nuclear Information System (INIS)

    Mutagenic treatment was made of the haploid stem apexes rape strain '9841' and '9885' with Pingyangmycin. As a result of positive selection with oxalic acid providing selection pressure, variants with significantly higher tolerance to oxalic acid than the original ones were obtained. 3 germplasm with significantly higher resistance to Sclerotinia sclerotiorum than cultivar Hu You 12 were selected from field test

  1. Role of antioxidant enzymes in bacterial resistance to organic acids.

    Science.gov (United States)

    Bruno-Bárcena, Jose M; Azcárate-Peril, M Andrea; Hassan, Hosni M

    2010-05-01

    Growth in aerobic environments has been shown to generate reactive oxygen species (ROS) and to cause oxidative stress in most organisms. Antioxidant enzymes (i.e., superoxide dismutases and hydroperoxidases) and DNA repair mechanisms provide protection against ROS. Acid stress has been shown to be associated with the induction of Mn superoxide dismutase (MnSOD) in Lactococcus lactis and Staphylococcus aureus. However, the relationship between acid stress and oxidative stress is not well understood. In the present study, we showed that mutations in the gene coding for MnSOD (sodA) increased the toxicity of lactic acid at pH 3.5 in Streptococcus thermophilus. The inclusion of the iron chelators 2,2'-dipyridyl (DIP), diethienetriamine-pentaacetic acid (DTPA), and O-phenanthroline (O-Phe) provided partial protection against 330 mM lactic acid at pH 3.5. The results suggested that acid stress triggers an iron-mediated oxidative stress that can be ameliorated by MnSOD and iron chelators. These findings were further validated in Escherichia coli strains lacking both MnSOD and iron SOD (FeSOD) but expressing a heterologous MnSOD from S. thermophilus. We also found that, in E. coli, FeSOD did not provide the same protection afforded by MnSOD and that hydroperoxidases are equally important in protecting the cells against acid stress. These findings may explain the ability of some microorganisms to survive better in acidified environments, as in acid foods, during fermentation and accumulation of lactic acid or during passage through the low pH of the stomach. PMID:20305033

  2. Chemical Acidic Attack Resistance of Lightweight Concrete with Additives

    Directory of Open Access Journals (Sweden)

    Salwa H. Ahmed

    2013-04-01

    Full Text Available  This research was studied the effect of H2SO4(8% , HCl (8% acidic and wastewaterpH= 5.1, SO4= = 850mg/L, Cl-=750 mg/L , TDS = 2500 mg/L( on the lightweight concrete by using limestone as lightweight aggregate and using the foam material (LightCrete. Super plasticizers (SP also used to enhance the properties of the lightweight concrete. Studying the effect of acidic solution and wastewater was done by calculating the percentage of decrease in weight and compressive strength of concrete prisms (100 * 100 * 400 mm, where the small portion of the flexural modulus test was submerged completely in the above solutions,  and the salt rising was observed by immersion (100 mm depth from the second portion of the prism in the above solutions. اظهرت نتائج الفحوصات ان H 2 SO 4 يكون تأثيره اكثر من HCl بالنسبة للنقصان بالوزن على الخرسانة الاعتيادية  بينما يكون تأثير HCl كبير على الخرسانة خفيفة الوزن بأستخدام الركام خفيف الوزن (Limestone وتأثيره اقل من H 2 SO 4 بالنسبة للخرسانة خفيفة الوزن باستخدام المادة الرغوية . Results show that the H2SO4 have influence larger than HCl for the decrease of weight on the normal concrete while the effect of HCl was larger than H2SO4  on lightweight concrete with limestone and its effect was less than H2SO4 on the lightweight concrete with foam. وكذلك تبين ان تأثير H 2 SO 4 على الخرسانة الاعتيادية بالنسبة للنقصان بالمقاومة يكون اقل من تاثير HCl بينما يكون تاثير H 2 SO 4 كبير على الخرسانة خفيفة الوزن الحاوية على المادة الرغوية وتاثيره اقل على الخرسانة خفيفة الوزن الحاوية على SP و Limestone . The results also shown that the effect of H2SO4 on the normal

  3. Protection of NdFeB magnets by corrosion resistance phytic acid conversion film

    Science.gov (United States)

    Nan, Haiyang; Zhu, Liqun; Liu, Huicong; Li, Weiping

    2015-11-01

    Phytic acid conversion film was prepared on NdFeB magnets by dipping the NdFeB into phytic acid solution. The morphology, composition, structure and corrosion resistance of the film were systematically investigated. The results showed that the phytic acid film was effective in improving the corrosion resistance of NdFeB magnets. XRD, TEM and FT-IR analyses revealed that the film was amorphous and had a strong peak of phosphate radical (PO43-). The formation mechanism of the film was also explored by XPS and the potential of zero charge (Epzc) measurement at the solution-metal interface.

  4. Investigation of Nalidixic Acid Resistance Mechanism in Salmonella enterica Using Molecular Simulation Techniques.

    Science.gov (United States)

    Preethi, B; Shanthi, V; Ramanathan, K

    2015-09-01

    The emergence of nalidixic acid-resistant strains of Salmonella typhimurium remains to be a major public health problem. In particular, the substitution of Asn in place of Asp at the 87 loci in the GyrA of S. typhimurium was experimentally stated for nalidixic acid resistance. However, the data on the possible mechanism of nalidixic acid resistance are limited. In this study, I-Mutant2.0 and DUET program were employed to explore the impact of mutation on the stability of GyrA protein. Subsequently, molecular simulation techniques were employed to provide detailed information on the nalidixic acid-resistant associates with the D87N mutation in the GyrA of S. typhimurium. The binding free energy data depicts that nalidixic acid forms stable complex only with native-type GyrA than mutant (D87N) type GyrA protein. Moreover, our results theoretically suggest that hydrogen bonding formed by the Arg91 is certainly responsible for the GyrA of S. typhimurium drug selectivity. It is hoped that these evidences are immensely important for the development of new antibiotic and to overcome the nalidixic acid resistance in the near future. PMID:26208690

  5. Antibiotic Resistance of Probiotic Strains of Lactic Acid Bacteria Isolated from Marketed Foods and Drugs

    Institute of Scientific and Technical Information of China (English)

    CHANG LIU; ZHUO-YANG ZHANG; KE DONG; JIAN-PING YUAN; XIAO-KUI GUO

    2009-01-01

    Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probioties. Methods Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR. Results Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis. Conclusion Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.

  6. Acid Tolerance Response of Anaerobic Sludge with Butyric Acid Stress during the Enhanced Biohydrogen Process%生物产氢过程中厌氧污泥耐酸响应的生物化学机制

    Institute of Scientific and Technical Information of China (English)

    孟影; 张光生; 王爱杰; 严群

    2012-01-01

    During the anaerobic digestion of biomass,large amounts of organic acids were produced. This results in an inhibitory effect on anaerobic microbiology,which in turn inhibits large-scale production of hydrogen. In this study, butyric acid was use as stress on the sludge, and it was found that the production rates of butyric acid, acetic acid and hydrogenwas reached at 400 mmol/mol, 1100 mmol/mol, 3690 mL/mol, respectively, which was higher 110%, 54% and 65% than that of the corresponding values in the control group. Moreover, glutamate acid decarboxylase (GAD) activity, dehydrogenase activity and the content of DNA was in-creased to 11. 6 ,μm/(g · TS · h), 6982. 12 μg TF/(g · TS · h) 14. 72 ng/mL, with an increment of 48%, 50%, 10.7%, respectively, and the content of extracellular polymeric substances (EPS) have improved significantly, loose bound protein, loose bound polysaccharide, tight bound protein and tight bound polysaccharide content were 147%, 34. 8%, 35%, 21. 6% higher than that of the control. The results demonstrate that the appropriate concentration of butyric acid stress on sludge can excite acid tolerance response (Acid tolerance response, ATR) and to improve acid tolerance of sludge, and improve the efficiency of anaerobic hydrogen production.%生物质厌氧发酵产氢过程中积累的大量酸性物质,会对厌氧微生物产生抑制作用,进而制约氢气的持续产生.作者采用不同浓度丁酸对污泥进行胁迫,结果表明:当丁酸胁迫质量浓度为6 g/L时,污泥厌氧发酵过程中丁酸、乙酸以及氢气产量最高,分别达到1 071 mmol/mol,462mmol/mol和3 690 mL/mol,比对照组分别提高了110%,54%和65%;此外,产氢过程中谷氨酸脱羧酶(glutamic acid decarboxylase,GAD)、脱氢酶以及DNA总量活性最高达到11.6μmol/(g·TS·h),6 982.12 μg TF/(g·TS·h),14.72 ng/mL,相对于对照组分别提高了48%,50%,10.7%;同时,经过酸胁迫后,

  7. Long-Term n-Caproic Acid Production from Yeast-Fermentation Beer in an Anaerobic Bioreactor with Continuous Product Extraction.

    Science.gov (United States)

    Ge, Shijian; Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

    2015-07-01

    Multifunctional reactor microbiomes can elongate short-chain carboxylic acids (SCCAs) to medium-chain carboxylic acids (MCCAs), such as n-caproic acid. However, it is unclear whether this microbiome biotechnology platform is stable enough during long operating periods to consistently produce MCCAs. During a period of 550 days, we improved the operating conditions of an anaerobic bioreactor for the conversion of complex yeast-fermentation beer from the corn kernel-to-ethanol industry into primarily n-caproic acid. We incorporated and improved in-line, membrane liquid-liquid extraction to prevent inhibition due to undissociated MCCAs at a pH of 5.5 and circumvented the addition of methanogenic inhibitors. The microbiome accomplished several functions, including hydrolysis and acidogenesis of complex organic compounds and sugars into SCCAs, subsequent chain elongation with undistilled ethanol in beer, and hydrogenotrophic methanogenesis. The methane yield was 2.40 ± 0.52% based on COD and was limited by the availability of carbon dioxide. We achieved an average n-caproate production rate of 3.38 ± 0.42 g L(-1) d(-1) (7.52 ± 0.94 g COD L(-1) d(-1)) with an n-caproate yield of 70.3 ± 8.81% and an n-caproate/ethanol ratio of 1.19 ± 0.15 based on COD for a period of ∼55 days. The maximum production rate was achieved by increasing the organic loading rates in tandem with elevating the capacity of the extraction system and a change in the complex feedstock batch. PMID:25941741

  8. Effects of pH, acidity and alkalinity on the microbiota activity of an anaerobic sludge blanket reactor (UASB treating pigmanure effluents

    Directory of Open Access Journals (Sweden)

    Fabricio Moterani

    2009-12-01

    Full Text Available The anaerobic processes used for treating wastewater have been often applied mainly for optimizing treatment systems. Among many of these systems, the UASB is one of the most successfully used. This type of reactor presents a good condition for microorganisms development, and therefore, for organic matter degradation. As a result, the goal of this research was to evaluate the effect of parameters, such as: temperature, pH, acidity and alkalinity on the microorganisms consortia, acclimatized in an UASB reactor, and simultaneously, observing the sludge morphology through a scanning electronic microscopy (SEM, in order to identify the response of the bacteria consortia under this environmental circumstances. The biomass operated under a mesophilic temperature, varying from 190C to 210C. The maximum concentration of volatile acids was 100 mg L-1, and the volumetric organic loading rate was 59 kgCOD m-3d-1. The total alkalinity concentration values were between 2500 and 5550 mgCaCO3 L-1. The average pH value of the sludge was 7.3. Under these conditions it was observed the development of a well acclimatized granular biomass, composed mainly of filamentous bacteria.

  9. Thermophilic anaerobic co-digestion of sewage sludge with grease waste: Effect of long chain fatty acids in the methane yield and its dewatering properties

    International Nuclear Information System (INIS)

    Highlights: • Thermophilic anaerobic codigestion of sewage sludge and grease waste (GW) doubles methane yield. • High GW doses in the influent leads to instability and LCFA accumulation in the effluent. • GW addition promotes acetoclastic activity whilst worsening the hydrogenothrophic activity. • The mesophilic codigestion with GW performs better than the thermophilic one. - Abstract: Thermophilic co-digestion of sewage sludge with three different doses of trapped grease waste (GW) from the pre-treatment of a WWTP has been assessed in a CSTR bench-scale reactor. After adding 12% and 27% of grease waste (on COD basis), the organic loading rate increased from 2.2 to 2.3 and 2.8 kgCOD m−3 d−1 respectively, and the methane yield increased 1.2 and 2.2 times. Further GW increase (37% on COD basis) resulted in an unstable methane yield and in long chain fatty acids (LCFA) accumulation. Although this inestability, the presence of volatile fatty acids in the effluent was negligible, showing good adaptation to fats of the thermophilic biomass. Nevertheless, the presence of LCFA in the effluent worsens its dewatering properties. Specific methanogenic activity tests showed that the addition of grease waste ameliorates the acetoclastic activity in detriment of the hydrogenotrophic activity, and suggests that the tolerance to LCFA can be further enhanced by slowly increasing the addition of lipid-rich materials

  10. Impact of the substrate loading regime and phosphoric acid supplementation on performance of biogas reactors and microbial community dynamics during anaerobic digestion of chicken wastes.

    Science.gov (United States)

    Belostotskiy, Dmitry E; Ziganshina, Elvira E; Siniagina, Maria; Boulygina, Eugenia A; Miluykov, Vasili A; Ziganshin, Ayrat M

    2015-10-01

    This study evaluates the effects of increasing organic loading rate (OLR) and decreasing hydraulic retention time (HRT) as well as phosphoric acid addition on mesophilic reactors' performance and biogas production from chicken wastes. Furthermore, microbial community composition in reactors was characterized by a 16S rRNA gene-based pyrosequencing analysis. Each step of increasing OLR impacted on the activity of microorganisms what caused a temporary decrease in biogas production. The addition of phosphoric acid resulted in the increased biogas production with values between 361 and 447 mL g(VS)(-1) from day 61 to day 74 compared to control reactor (309-350 mL g(VS)(-1)). With reactors' operation, Bacteroidetes phylotypes were noticeably replaced with Firmicutes representatives, and significant increase of Clostridium sp. was identified. Within Euryarchaeota, Methanosarcina sp. dominated in all analyzed samples, in which high ammonium levels were detected (3.4-4.9 NH4(+)-N g L(-1)). These results can help in better understanding the anaerobic digestion process of simultaneously ammonium/phosphate-rich substrates.

  11. Oxidation-Resistant Coating For Bipolar Lead/Acid Battery

    Science.gov (United States)

    Bolstad, James J.

    1993-01-01

    Cathode side of bipolar substrate coated with nonoxidizable conductive layer. Coating prepared as water slurry of aqueous dispersion of polyethylene copolymer plus such conductive fillers as tin oxide, titanium, tantalum, or tungsten oxide. Applied easily to substrate of polyethylene carbon plastic. As slurry dries, conductive, oxidation-resistant coating forms on positive side of substrate.

  12. The role of dietary acid load and mild metabolic acidosis in insulin resistance in humans.

    Science.gov (United States)

    Williams, Rebecca S; Kozan, Pinar; Samocha-Bonet, Dorit

    2016-05-01

    Type 2 diabetes is increasingly being recognised as a global health crisis (World Health Organisation). Insulin resistance is closely associated with obesity and precedes the development of type 2 diabetes. However, there is now increasing evidence to suggest that diet itself may independently be associated with type 2 diabetes risk. A diet with a high acid load (or high potential renal net acid load, PRAL) can result in a decrease in pH towards the lower end of the normal physiological range, which may in turn lead to the development of insulin resistance. Conversely, reducing dietary acid load (the so called 'alkaline diet') may be protective and prevent the onset of type 2 diabetes. Here, we explore the influence of dietary acid load on the development of mild metabolic acidosis and induction of insulin resistance. Whilst large prospective cohort studies link high dietary acid load or low serum bicarbonate with the development of type 2 diabetes, the effect of a diet with a low acid (or high alkaline) load remains unclear. Further interventional studies are required to investigate the influence of dietary composition on the body's acid/base balance, insulin resistance and incidence of type 2 diabetes. PMID:26363101

  13. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  14. Mycolic Acid Cyclopropanation is Essential for Viability, Drug Resistance, and Cell Wall Integrity of Mycobacterium tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Barkan, Daniel; Liu, Zhen; Sacchettini, James C.; Glickman, Michael S.; (MSKCC); (TAM)

    2009-12-01

    Mycobacterium tuberculosis infection remains a major global health problem complicated by escalating rates of antibiotic resistance. Despite the established role of mycolic acid cyclopropane modification in pathogenesis, the feasibility of targeting this enzyme family for antibiotic development is unknown. We show through genetics and chemical biology that mycolic acid methyltransferases are essential for M. tuberculosis viability, cell wall structure, and intrinsic resistance to antibiotics. The tool compound dioctylamine, which we show acts as a substrate mimic, directly inhibits the function of multiple mycolic acid methyltransferases, resulting in loss of cyclopropanation, cell death, loss of acid fastness, and synergistic killing with isoniazid and ciprofloxacin. These results demonstrate that mycolic acid methyltransferases are a promising antibiotic target and that a family of virulence factors can be chemically inhibited with effects not anticipated from studies of each individual enzyme.

  15. The Pleiotropic Antibacterial Mechanisms of Ursolic Acid against Methicillin-Resistant Staphylococcus aureus (MRSA).

    Science.gov (United States)

    Wang, Chao-Min; Jhan, Yun-Lian; Tsai, Shang-Jie; Chou, Chang-Hung

    2016-01-01

    (1) BACKGROUND: Several triterpenoids were found to act synergistically with classes of antibiotic, indicating that plant-derived chemicals have potential to be used as therapeutics to enhance the activity of antibiotics against multidrug-resistant pathogens. However, the mode of action of triterpenoids against bacterial pathogens remains unclear. The objective of this study is to evaluate the interaction between ursolic acid against methicillin-resistant Staphylococcus aureus (MRSA); (2) METHODS: The ability of ursolic acid to damage mammalian and bacterial membranes was examined. The proteomic response of methicillin-resistant S. aureus in ursolic acid treatment was investigated using two-dimensional (2D) proteomic analysis; (3) RESULTS: Ursolic acid caused the loss of staphylococcal membrane integrity without hemolytic activity. The comparison of the protein pattern of ursolic acid-treated and normal MRSA cells revealed that ursolic acid affected a variety of proteins involved in the translation process with translational accuracy, ribonuclease and chaperon subunits, glycolysis and oxidative responses; (4) CONCLUSION: The mode of action of ursolic acid appears to be the influence on the integrity of the bacterial membrane initially, followed by inhibition of protein synthesis and the metabolic pathway. These findings reflect that the pleiotropic effects of ursolic acid against MRSA make it a promising antibacterial agent in pharmaceutical research. PMID:27399657

  16. Salicylic acid and jasmonic acid are essential for systemic resistance against tobacco mosaic virus in Nicotiana benthamiana.

    Science.gov (United States)

    Zhu, Feng; Xi, De-Hui; Yuan, Shu; Xu, Fei; Zhang, Da-Wei; Lin, Hong-Hui

    2014-06-01

    Systemic resistance is induced by pathogens and confers protection against a broad range of pathogens. Recent studies have indicated that salicylic acid (SA) derivative methyl salicylate (MeSA) serves as a long-distance phloem-mobile systemic resistance signal in tobacco, Arabidopsis, and potato. However, other experiments indicate that jasmonic acid (JA) is a critical mobile signal. Here, we present evidence suggesting both MeSA and methyl jasmonate (MeJA) are essential for systemic resistance against Tobacco mosaic virus (TMV), possibly acting as the initiating signals for systemic resistance. Foliar application of JA followed by SA triggered the strongest systemic resistance against TMV. Furthermore, we use a virus-induced gene-silencing-based genetics approach to investigate the function of JA and SA biosynthesis or signaling genes in systemic response against TMV infection. Silencing of SA or JA biosynthetic and signaling genes in Nicotiana benthamiana plants increased susceptibility to TMV. Genetic experiments also proved the irreplaceable roles of MeSA and MeJA in systemic resistance response. Systemic resistance was compromised when SA methyl transferase or JA carboxyl methyltransferase, which are required for MeSA and MeJA formation, respectively, were silenced. Moreover, high-performance liquid chromatography-mass spectrometry analysis indicated that JA and MeJA accumulated in phloem exudates of leaves at early stages and SA and MeSA accumulated at later stages, after TMV infection. Our data also indicated that JA and MeJA could regulate MeSA and SA production. Taken together, our results demonstrate that (Me)JA and (Me)SA are required for systemic resistance response against TMV. PMID:24450774

  17. Clinically significant anaerobic bacteria isolated from patients in a South African academic hospital: antimicrobial susceptibility testing.

    Science.gov (United States)

    Naidoo, S; Perovic, O; Richards, G A; Duse, A G

    2011-09-27

    BACKGROUND. Increasing resistance to some antimicrobial agents among anaerobic bacteria has made susceptibility patterns less predictable. METHOD. This was a prospective study of the susceptibility data of anaerobic organisms isolated from clinical specimens from patients with suspected anaerobic infections from June 2005 until February 2007. Specimens were submitted to the microbiology laboratory at Charlotte Maxeke Johannesburg Academic Hospital, where microscopy, culture and susceptibility testing were performed the using E test® strip minimum inhibitory concentration method. Results were interpreted with reference to Clinical and Laboratory Standards Institute guidelines for amoxicillin-clavulanate, clindamycin, metronidazole, penicillin, ertapenem, cefoxitin, ceftriaxone, chloramphenicol and piperacillin-tazobactam. RESULTS. One hundred and eighty anaerobic isolates were submitted from 165 patients. The most active antimicrobial agents were chloramphenicol (100% susceptible), ertapenem (97.2%), piperacillin-tazobactam (99.4%) and amoxicillin-clavulanic acid (96.7%). Less active were metronidazole (89.4%), cefoxitin (85%), clindamycin (81.7%), ceftriaxone (68.3%) and penicillin (33.3%). CONCLUSION. Susceptibility testing should be performed periodically to identify emerging trends in resistance and to modify empirical treatment of anaerobic infections.

  18. Protection of 2024-T3 aluminium alloy by corrosion resistant phytic acid conversion coating

    Science.gov (United States)

    Shi, Hongwei; Han, En-Hou; Liu, Fuchun; Kallip, Silvar

    2013-09-01

    The corrosion protection properties of environmentally friendly phytic acid conversion coatings were studied on 2024-T3 aluminium alloy. The films were prepared under acidic conditions with various pH values and characterised by SEM, EDS, ATR-FTIR and electrochemical techniques. The results indicate that the conversion coatings obtained by immersing the alloy in phytic acid solutions at pH from 3 to 5.5 provide excellent corrosion resistance. ATR-FTIR confirms that the film is formed by deposition of reaction products between Al3+ and phosphate groups in phytic acid molecules. The conformation models of the deposition film are proposed.

  19. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment...

  20. Antioxidant enzymes and fatty acid composition as related to disease resistance in postharvest loquat fruit.

    Science.gov (United States)

    Cao, Shifeng; Yang, Zhenfeng; Cai, Yuting; Zheng, Yonghua

    2014-11-15

    Two cultivars of loquat fruit were stored at 20°C for 10days to investigate the relationship between disease resistance, and fatty acid composition and activities of endogenous antioxidant enzymes. The results showed that decay incidence increased with storage time in both cultivars. A significantly lower disease incidence was observed in 'Qingzhong' fruit than in 'Fuyang', suggesting 'Qingzhong' had increased disease resistance. Meanwhile, 'Qingzhong' fruit also had lower levels of superoxide radical and hydrogen peroxide, and lower lipoxygenase activity, but higher levels of linolenic and linoleic acids and higher activities of catalase (CAT) and ascorbate peroxidase (APX) compared with 'Fuyang'. These results suggest that the higher levels of linolenic and linoleic acids and the higher activity of CAT and APX have a role in disease resistance of postharvest loquat fruit.

  1. Effect of phytic acid on the microstructure and corrosion resistance of Ni coating

    Energy Technology Data Exchange (ETDEWEB)

    Meng Guozhe, E-mail: mengguozhe@hrbeu.edu.c [Corrosion and Protection Laboratory, Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Ministry of Education, Harbin 150001 (China)] [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Sun Feilong [Corrosion and Protection Laboratory, Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Ministry of Education, Harbin 150001 (China); Shaoa Yawei [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Zhang Tao; Wang Fuhui [Corrosion and Protection Laboratory, Key Laboratory of Superlight Materials and Surface Technology, Harbin Engineering University, Ministry of Education, Harbin 150001 (China)] [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Dong Chaofang [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China); Li, Xiaogang [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)] [Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083 (China)

    2010-08-01

    In this work, the pure Ni coatings were synthesized on Q235 steel by using reverse pulsed electrodeposition technique in sulphate-based baths with 0, 0.1, 0.2 and 0.3 g/L phytic acid additive. The effect of phytic acid on the microstructure and micro-morphology of the sample was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. And the effect of phytic acid on the corrosion resistance of the sample was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that the addition of phytic acid was in favor of the growth of nano-scale twins (NT) in the interior of grains, which was due to the lowered stacking fault energies of Ni during the electrodeposition, and the typical morphology of pyramidal islands on the surface. The results also demonstrated that the effect of phytic acid was not monotonous with increasing concentration: the passive current density i{sub p} was minimum and the charge transfer resistance R{sub t} was maximum for the sample obtained from the bath with 0.2 g/L phytic acid, indicating that the sample obtained from the bath with 0.2 g/L phytic acid showed the best corrosion resistance.

  2. Effect of phytic acid on the microstructure and corrosion resistance of Ni coating

    International Nuclear Information System (INIS)

    In this work, the pure Ni coatings were synthesized on Q235 steel by using reverse pulsed electrodeposition technique in sulphate-based baths with 0, 0.1, 0.2 and 0.3 g/L phytic acid additive. The effect of phytic acid on the microstructure and micro-morphology of the sample was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. And the effect of phytic acid on the corrosion resistance of the sample was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that the addition of phytic acid was in favor of the growth of nano-scale twins (NT) in the interior of grains, which was due to the lowered stacking fault energies of Ni during the electrodeposition, and the typical morphology of pyramidal islands on the surface. The results also demonstrated that the effect of phytic acid was not monotonous with increasing concentration: the passive current density ip was minimum and the charge transfer resistance Rt was maximum for the sample obtained from the bath with 0.2 g/L phytic acid, indicating that the sample obtained from the bath with 0.2 g/L phytic acid showed the best corrosion resistance.

  3. Glutamine, glutamate, and arginine-based acid resistance in Lactobacillus reuteri.

    Science.gov (United States)

    Teixeira, Januana S; Seeras, Arisha; Sanchez-Maldonado, Alma Fernanda; Zhang, Chonggang; Su, Marcia Shu-Wei; Gänzle, Michael G

    2014-09-01

    This study aimed to determine whether glutamine deamidation improves acid resistance of Lactobacillus reuteri, and to assess whether arginine, glutamine, and glutamate-mediated acid resistance are redundant or complementary mechanisms of acid resistance. Three putative glutaminase genes, gls1, gls2, and gls3, were identified in L. reuteri 100-23. All three genes were expressed during growth in mMRS and wheat sourdough. L. reuteri consistently over-expressed gls3 and the glutamate decarboxylase gadB. L. reuteri 100-23ΔgadB over-expressed gls3 and the arginine deiminase gene adi. Analysis of the survival of L. reuteri in acidic conditions revealed that arginine conversion is effective at pH of 3.5 while glutamine or glutamate conversion were effective at pH of 2.5. Arginine conversion increased the pHin but not ΔΨ; glutamate decarboxylation had only a minor effect on the pHin but increased the ΔΨ. This study demonstrates that glutamine deamidation increases the acid resistance of L. reuteri independent of glutamate decarboxylase activity. Arginine and glutamine/glutamate conversions confer resistance to lactate at pH of 3.5 and phosphate at pH of 2.5, respectively. Knowledge of L. reuteri's acid resistance improves the understanding of the adaptation of L. reuteri to intestinal ecosystems, and facilitates the selection of probiotic and starter cultures.

  4. Skeletal muscle protein anabolic response to resistance exercise and essential amino acids is delayed with aging

    OpenAIRE

    Drummond, Micah J.; Dreyer, Hans C.; Pennings, Bart; Fry, Christopher S.; Dhanani, Shaheen; Dillon, Edgar L.; Sheffield-Moore, Melinda; Volpi, Elena; Rasmussen, Blake B.

    2008-01-01

    Skeletal muscle loss during aging leads to an increased risk of falls, fractures, and eventually loss of independence. Resistance exercise is a useful intervention to prevent sarcopenia; however, the muscle protein synthesis (MPS) response to resistance exercise is less in elderly compared with young subjects. On the other hand, essential amino acids (EAA) increase MPS equally in both young and old subjects when sufficient EAA is ingested. We hypothesized that EAA ingestion following a bout o...

  5. Novel nickel resistance genes from the rhizosphere metagenome of plants adapted to acid mine drainage

    OpenAIRE

    Mirete, Salvador; González de Figueras, Carolina; González-Pastor, José Eduardo

    2007-01-01

    Metal resistance determinants have traditionally been found in cultivated bacteria. To search for genes involved in nickel resistance, we analyzed the bacterial community of the rhizosphere of Erica andevalensis, an endemic heather which grows at the banks of the Tinto River, a naturally metal-enriched and extremely acidic environment in southwestern Spain. 16S rRNA gene sequence analysis of rhizosphere DNA revealed the presence of members of five phylogenetic groups of Bacteria and the two m...

  6. Antimicrobial resistance of coagulase-negative staphylococci and lactic acid bacteria from industrially produced dairy products

    Directory of Open Access Journals (Sweden)

    Nevijo Zdolec

    2013-03-01

    Full Text Available In this research, the susceptibility to clindamycin, tetracycline, amikacin, amoxicillin + clavulanic acid, enrofloxacine, vancomycin, trimethoprim + sulphametoxazol, tobramycin, chloramphenicol, ciprofloxacin, erythromycin, penicillin and trimethoprim was tested in coagulase-negative staphylococci (n=78 and lactic acid bacteria (n=30 by means of disk diffusion test and E-test. The isolates were collected from soft and hard cheeses, butter and brine. All isolates of coagulase-negative staphylococci were susceptible to clindamycin, amikacin, amoxicillin + clavulanic acid, enrofloxacine, vancomycin, chloramphenicol and ciprofloxacin according to CLSI breakpoints. A total of 30 staphylococci isolates (38.46 % were resistant to erythromycin, 18 to penicillin (23.07 %, 4 to tetracycline (5.12 %, and one isolate to trimethoprim, tobramicin and trimethoprim + sulphametoxazol (1.28 %. Among 78 tested staphylococci, 35 of them were resistant to at least one antimicrobial substance (44.87 %. The rate of resistant isolates of different soft cheese types ranged from 22 to 70 %, while resistant staphylococci were absent in hard cheese and brine. The growth of lactic acid bacteria was not influenced by trimethoprim + sulphametoxazol (n=29, vancomycin (n=29, trimethoprim (n=28, amikacin (n=10 and tobramycin (n=10. The results show that significant part of apathogenic microbiota in different dairy products is phenotypically resistant to antimicrobial agents.

  7. The role of humic substances in the anaerobic reductive dechlorination of 2,4-dichlorophenoxyacetic acid by Comamonas koreensis strain CY01

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yibo [College of Life Sciences, South China Normal University, Guangdong Key Lab of Biotechnology for Plant Development, Guangzhou, 510631 (China)] [Guangdong Institute of Eco-environment and Soil Sciences, Guangzhou, 510650 (China)] [College of Life Science and Chemistry, Tianshui Normal University, Tianshui, 741000 (China); Wu Chunyuan [Guangdong Institute of Eco-environment and Soil Sciences, Guangzhou, 510650 (China); Wang Xiaojing, E-mail: wangyb02@163.com [College of Life Sciences, South China Normal University, Guangdong Key Lab of Biotechnology for Plant Development, Guangzhou, 510631 (China); Zhou Shungui, E-mail: sgzhou@soil.gd.cn [Guangdong Institute of Eco-environment and Soil Sciences, Guangzhou, 510650 (China)

    2009-05-30

    The role of the humic model compound, anthraquinone-2,6-disulfonate (AQDS), in the anaerobic reductive dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D) by the Fe(III)- and humic substances (HS)-reducing bacterium, Comamonas koreensis strain CY01 was investigated. The results taken as a whole indicated that (i) strain CY01 could couple glucose oxidation to 2,4-D reductive dechlorination; (ii) reductive dechlorination of 2,4-D by strain CY01 was greatly stimulated by the addition of AQDS; (iii) the transfer of electrons from biogenic AH{sub 2}QDS to 2,4-D was an abiotic process which can take place in the absence of microorganisms; and (iv) AH{sub 2}QDS was reoxidized during the chemical reaction, AQDS can serve again as electron acceptor for microorganisms, thus acting as electron shuttles. All the results suggested that 2,4-D reductive dechlorination by CY01 strain was a biochemical process that oxidizes the electron donors and transfers the electron to the acceptors through redox mediator, AQDS. We proposed the possible mechanism for the HS dependent reduction of 2,4-D. Our results suggested that microbial reduction of HS and subsequent chemical reduction of organic pollutants represent an important path of electron flow in anoxic natural environments. This work is a necessary preliminary step for better understanding the biodegradation of 2,4-D in subsurface soil.

  8. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  9. Development of a SCAR (sequence-characterised amplified region) marker for acid resistance-related gene in Lactobacillus plantarum.

    Science.gov (United States)

    Liu, Shu-Wen; Li, Kai; Yang, Shi-Ling; Tian, Shu-Fen; He, Ling

    2015-03-01

    A sequence characterised amplified region marker was developed to determine an acid resistance-related gene in Lactobacillus plantarum. A random amplified polymorphic DNA marker named S116-680 was reported to be closely related to the acid resistance of the strains. The DNA band corresponding to this marker was cloned and sequenced with the induction of specific designed PCR primers. The results of PCR test helped to amplify a clear specific band of 680 bp in the tested acid-resistant strains. S116-680 marker would be useful to explore the acid-resistant mechanism of L. plantarum and to screen desirable malolactic fermentation strains.

  10. Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

    Science.gov (United States)

    Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

    2016-08-23

    Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis.

  11. Tetradecylthioacetic acid prevents high fat diet induced adiposity and insulin resistance

    DEFF Research Database (Denmark)

    Madsen, Lise; Guerre-Millo, Michéle; Flindt, Esben N;

    2002-01-01

    Tetradecylthioacetic acid (TTA) is a non-beta-oxidizable fatty acid analog, which potently regulates lipid homeostasis. Here we evaluate the ability of TTA to prevent diet-induced and genetically determined adiposity and insulin resistance. In Wistar rats fed a high fat diet, TTA administration...... completely prevented diet-induced insulin resistance and adiposity. In genetically obese Zucker (fa/fa) rats TTA treatment reduced the epididymal adipose tissue mass and improved insulin sensitivity. All three rodent peroxisome proliferator-activated receptor (PPAR) subtypes were activated by TTA...... that a TTA-induced increase in hepatic fatty acid oxidation and ketogenesis drains fatty acids from blood and extrahepatic tissues and that this contributes significantly to the beneficial effects of TTA on fat mass accumulation and peripheral insulin sensitivity....

  12. Abscisic acid-cytokinin antagonism modulates resistance against pseudomonas syringae in Tobacco

    DEFF Research Database (Denmark)

    Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

    2014-01-01

    Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant...... immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction...... of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco...

  13. Enhancing Volatile Fatty Acid by anaerobic digestion using municipal sludge combined with multiple organics%污泥联合不同有机质对厌氧发酵产酸的影响

    Institute of Scientific and Technical Information of China (English)

    李骥延

    2016-01-01

    This paper studied the process of three main organic components(carbohydrates,proteins,lipids)anaerobic digestion with municipal sludge to inhancing Volatile Fatty Acid(VFA)product. According to the text,VFA achieves maximum production when anaerobic digestion com-bined with protein,the maximum yield reaches 14. 52 g/ L and 43. 47% productivity,increasing 218% and 59% respectively compared to sludge solo anaerobic digestion. Sludge combined with lipid produce only 39% yield of VFA compared to sludge solo anaerobic digestion.%研究了城市有机垃圾的三种主要成分(碳水化合物,蛋白质,脂质)与市政污泥联合厌氧发酵产酸的过程,试验结果表明,蛋白类有机质能大幅提高厌氧发酵效率,其后期产酸量达到14.52 g/ L,挥发酸产率43.47%,分别比污泥单独厌氧发酵提高218%和59%;污泥联合脂质厌氧发酵产酸量最低,仅为单独厌氧发酵产酸量的39%。

  14. Characterization and Functional Analysis of Pyrabactin Resistance-Like Abscisic Acid Receptor Family in Rice

    OpenAIRE

    Tian, Xiaojie; Wang, Zhenyu; Li, Xiufeng; Lv, Tianxiao; Liu, Huazhao; Wang, Lizhi; Niu, Hongbin; Bu, Qingyun

    2015-01-01

    Background Abscisic acid (ABA) plays crucial roles in regulating plant growth and development, especially in responding to abiotic stress. The pyrabactin resistance-like (PYL) abscisic acid receptor family has been identified and widely characterized in Arabidopsis. However, PYL families in rice were largely unknown. In the present study, 10 out of 13 PYL orthologs in rice (OsPYL) were isolated and investigated. Results Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) an...

  15. Antibacterial activity of mupirocin (pseudomonic Acid A) against, clinical isolates of methicillin-resistant staphylococcus aureus

    International Nuclear Information System (INIS)

    Colonized patients and health care workers are the main source of spread of methicillin resistant Staphylococcus aureus (MRSA) in hospitals. The elimination of nasal colonized MRSA plays a crucial role in infection control protocols. Mupirocin (pseudomonic acid A) is used for eradication of MRSA nasal carriage. Increasing use of pseudomonic acid A (mupirocin) has led to emergence of resistance. Objective To determine low and high level resistance of MRSA isolates from clinical specimens against mupirocin. Place and duration of study: Study was conducted at Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi from July 2006 to June 2007. Material and methods Three hundred methicillin-resistant Staphylococcus aureus isolates were studied. All clinical specimens were processed for culture and sensitivity. Staphylococcus aureus isolates were tested for methicillin resistance using 1 micro g oxacillin disk. The isolates were further tested by PCR for the presence of mecA gene. Minimum Inhibitory Concentration (MIC) of mupirocin against MRSA isolates was determined using agar dilution technique. Results Out of 300 MRSA isolates, 98% were found to have MlC against mupirocin as smaller than 4 micro g/mL. Remaining 2% isolates revealed low level resistance (MIC greater than 8 micro g/mL to 256 micro g/mL), no high level resistance (MIC greater than 512 micro g/mL) against mupirocin was detected. Conclusions: High level mupirocin resistance has not emerged so far in our setup. Due to increasing use of mupirocin, emergence of resistance against mupirocin among MRSA is a strong possibility. Strategy encompassing rational use of antimicrobials, hospital infection control, surveillance for the detection of mupirocin resistance and judicious use of this agent is required. (author)

  16. ACID RESISTANCE OF FLYASH BASED GEOPOLYMER MORTAR UNDER AMBIENT CURING AND HEAT CURING

    Directory of Open Access Journals (Sweden)

    V.Sreevidya

    2012-02-01

    Full Text Available An Experimental study was conducted to assess the Acid resistance of flyash based geopolymer mortar specimens of size 50x50x50mm with a ratio of flyash to sand as 1:3.The ratio between solution(Sodiumhydroxide and Sodium silicate solution to flyash were 0.376,0.386,0.396 and 0.416. After casting the specimens were subjected to both ambient curing and heat curing. In heat curing the specimens were kept continuously at 60oC for 24 hrs. Durability of specimens was assessed by immersing them in 5% of sulfuric acid and 5%hydrochloric acid for a period of 14 weeks. Evaluation of its resistance in terms of change in weight, compressive strength and visual appearance at regular intervals was carried out. After exposure in the acid solutions for 14 weeks, the samples showed very low weight loss. Results obtained from the present study indicate that Geopolymers are highly resistance to sulfuric acid and hydrochloric acid.

  17. Arabidopsis ENHANCED DISEASE SUSCEPTIBILITY1 promotes systemic acquired resistance via azelaic acid and its precursor 9-oxo nonanoic acid.

    Science.gov (United States)

    Wittek, Finni; Hoffmann, Thomas; Kanawati, Basem; Bichlmeier, Marlies; Knappe, Claudia; Wenig, Marion; Schmitt-Kopplin, Philippe; Parker, Jane E; Schwab, Wilfried; Vlot, A Corina

    2014-11-01

    Systemic acquired resistance (SAR) is a form of inducible disease resistance that depends on salicylic acid and its upstream regulator ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1). Although local Arabidopsis thaliana defence responses activated by the Pseudomonas syringae effector protein AvrRpm1 are intact in eds1 mutant plants, SAR signal generation is abolished. Here, the SAR-specific phenotype of the eds1 mutant is utilized to identify metabolites that contribute to SAR. To this end, SAR bioassay-assisted fractionation of extracts from the wild type compared with eds1 mutant plants that conditionally express AvrRpm1 was performed. Using high-performance liquid chromatography followed by mass spectrometry, systemic immunity was associated with the accumulation of 60 metabolites, including the putative SAR signal azelaic acid (AzA) and its precursors 9-hydroperoxy octadecadienoic acid (9-HPOD) and 9-oxo nonanoic acid (ONA). Exogenous ONA induced SAR in systemic untreated leaves when applied at a 4-fold lower concentration than AzA. The data suggest that in planta oxidation of ONA to AzA might be partially responsible for this response and provide further evidence that AzA mobilizes Arabidopsis immunity in a concentration-dependent manner. The AzA fragmentation product pimelic acid did not induce SAR. The results link the C9 lipid peroxidation products ONA and AzA with systemic rather than local resistance and suggest that EDS1 directly or indirectly promotes the accumulation of ONA, AzA, or one or more of their common precursors possibly by activating one or more pathways that either result in the release of these compounds from galactolipids or promote lipid peroxidation.

  18. Improved Acetic Acid Resistance in Saccharomyces cerevisiae by Overexpression of the WHI2 Gene Identified through Inverse Metabolic Engineering.

    Science.gov (United States)

    Chen, Yingying; Stabryla, Lisa; Wei, Na

    2016-01-29

    Development of acetic acid-resistant Saccharomyces cerevisiae is important for economically viable production of biofuels from lignocellulosic biomass, but the goal remains a critical challenge due to limited information on effective genetic perturbation targets for improving acetic acid resistance in the yeast. This study employed a genomic-library-based inverse metabolic engineering approach to successfully identify a novel gene target, WHI2 (encoding a cytoplasmatic globular scaffold protein), which elicited improved acetic acid resistance in S. cerevisiae. Overexpression of WHI2 significantly improved glucose and/or xylose fermentation under acetic acid stress in engineered yeast. The WHI2-overexpressing strain had 5-times-higher specific ethanol productivity than the control in glucose fermentation with acetic acid. Analysis of the expression of WHI2 gene products (including protein and transcript) determined that acetic acid induced endogenous expression of Whi2 in S. cerevisiae. Meanwhile, the whi2Δ mutant strain had substantially higher susceptibility to acetic acid than the wild type, suggesting the important role of Whi2 in the acetic acid response in S. cerevisiae. Additionally, overexpression of WHI2 and of a cognate phosphatase gene, PSR1, had a synergistic effect in improving acetic acid resistance, suggesting that Whi2 might function in combination with Psr1 to elicit the acetic acid resistance mechanism. These results improve our understanding of the yeast response to acetic acid stress and provide a new strategy to breed acetic acid-resistant yeast strains for renewable biofuel production.

  19. Effect of dilution and L-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

    International Nuclear Information System (INIS)

    In this study, H2 was produced in a two-stage biological process: I) first stage; the dark fermentation of cheese whey wastewater, which is rich in lactose, by mixed anaerobic culture grown at thermophilic temperature in a continuously running fermentor and ii) second stage; the photo-fermentation of the residual medium by R. palustris strain (DSM 127) at 31oC under illumination of 150 W in batch mode, respectively. In the first part of the study, the effluent from the dark fermentation reactor was used either as it is (no dilution) or after dilution with distilled water at varying ratios such as 1/2 , 1/5, 1/10 (1 volume effluent/5 volume distilled water) before used in photo-fermentation experiments. In the second part of the study, L-malic acid at varying amounts was added into the hydrogen production medium in order to have L-malic acid concentrations ranging from 0 to 4 g/l. Non-diluted and pre-diluted mediums with or without L-malic acid addition were also tested for comparison purpose (as controls). Prior to the hydrogen production experiments, all samples were subjected to pH adjustment, (pH 6.7) and sterilized by autoclave at 121oC for 15 min. In regards to the experiments in which the effect of dilution of the effluent from dark fermentation was studied, it was observed that dilution of the effluent from dark fermentation resulted in much better hydrogen productions. Among the dilution rates used, the experiments operated with 1/5 dilution ratio produced the best hydrogen production (241 ml H2/ g CODfed). On the other hand, it was seen that the mixing the effluent with L-malic acid (0 - 4 g/l) at increasing ratios (studied from 0% L-malic acid up to 100% by volume in the mixture) had further positive effect and improved the hydrogen production. The bioreactors containing only L-malic acid media resulted in the best hydrogen production (438 ml H2 / g CODfed). It was found that, undiluted raw cheese whey wastewater effluent from dark hydrogen production

  20. Effect of dilution and L-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Azbar, N.; Tuba, F.; Dokgoz, C. [Bioengineering Dept., Faculty of Engineering, Ege Univ., Izmir (Turkey)], E-mail: nuri.azbar@ege.edu.tr

    2009-07-01

    In this study, H{sub 2} was produced in a two-stage biological process: I) first stage; the dark fermentation of cheese whey wastewater, which is rich in lactose, by mixed anaerobic culture grown at thermophilic temperature in a continuously running fermentor and ii) second stage; the photo-fermentation of the residual medium by R. palustris strain (DSM 127) at 31{sup o}C under illumination of 150 W in batch mode, respectively. In the first part of the study, the effluent from the dark fermentation reactor was used either as it is (no dilution) or after dilution with distilled water at varying ratios such as 1/2 , 1/5, 1/10 (1 volume effluent/5 volume distilled water) before used in photo-fermentation experiments. In the second part of the study, L-malic acid at varying amounts was added into the hydrogen production medium in order to have L-malic acid concentrations ranging from 0 to 4 g/l. Non-diluted and pre-diluted mediums with or without L-malic acid addition were also tested for comparison purpose (as controls). Prior to the hydrogen production experiments, all samples were subjected to pH adjustment, (pH 6.7) and sterilized by autoclave at 121{sup o}C for 15 min. In regards to the experiments in which the effect of dilution of the effluent from dark fermentation was studied, it was observed that dilution of the effluent from dark fermentation resulted in much better hydrogen productions. Among the dilution rates used, the experiments operated with 1/5 dilution ratio produced the best hydrogen production (241 ml H{sub 2}/ g COD{sub fed}). On the other hand, it was seen that the mixing the effluent with L-malic acid (0 - 4 g/l) at increasing ratios (studied from 0% L-malic acid up to 100% by volume in the mixture) had further positive effect and improved the hydrogen production. The bioreactors containing only L-malic acid media resulted in the best hydrogen production (438 ml H{sub 2} / g COD{sub fed}). It was found that, undiluted raw cheese whey wastewater

  1. [Biological profile of tartrate-resistant acid phosphatase as a marker of bone resorption].

    Science.gov (United States)

    Rico, H; Iritia, M; Arribas, I; Revilla, M

    1990-12-01

    Tartrate-resistant serum acid phosphatase was measured in 123 subjects, 80 of which were normal and the rest pathologic, in order to define the profile and value of this parameter as a biological marker of osteoclastic activity. Normal subjects were divided into age groups based on the period where skeletal growth ends (under 20 years), at the age of menopause in women (50 years, between 20 and 50 years) and those over 50 years. There was an increase in tartrate-resistant serum acid phosphatase coinciding with puberty and no sex differences were observed after the 50 year mark, when women showed higher values than men (p less than 0.001). Such tartrate-resistant serum acid phosphatase increase, is reflected as higher values in the 50 year group than in the 20 to 50 year group (p less than 0.001), the only age limit where a negative significant correlation between tartrate-resistant serum acid phosphatase values and age could be observed (p less than 0.05). Values were higher up to the age of 20 years (p less than 0.001) than in any other older age group. Levels increased significantly (p less than 0.001 for both groups) in post-menopausal osteoporosis (n = 20) and in Paget's disease of bone (n = 15), and decreased significantly (p less than 0.05) in imperfect osteogenesis (n = 8), thus revealing its value as a biological marker of osteoclastic activity. PMID:2099535

  2. Acid pre-treatment of sewage anaerobic sludge to increase hydrogen producing bacteria HPB: effectiveness and reproducibility.

    Science.gov (United States)

    Tommasi, T; Sassi, G; Ruggeri, B

    2008-01-01

    The present study is aimed to test the effectiveness and the reproducibility of the acid pre-treatment of sewage sludge to suppress the methanogenic bacteria activity, in order to increase the hydrogen forming bacteria activity, mainly Clostridium species. The treated sludge has been tested on glucose reach medium under mesophilic conditions (35 degrees C), in batch mode to quantify the biological fermentative hydrogen production. In the whole series of experiments, the main components of biogas are hydrogen (52-60%) and carbon dioxide (40-48%); no methane and hydrogen sulphide were present in it. The rate of biogas production reached a maximum of 75 ml/lh. An overall mean hydrogen conversion efficiency was 11.20% on the assumption of maximum of 3 mol H2/mol glucose. Clostridium spp. multiplied ten times after 10 h of fermentation and over that thousand times at the end of fermentation.

  3. Study on the Resistance Induced by Salicylic Acid Against Phytophthora capsici in Pepper (Capsicum annuum)

    Institute of Scientific and Technical Information of China (English)

    MAO Ai-jun; WANG Yong-jian; FENG Lan-xiang; GENG San-sheng; XU Yong

    2005-01-01

    Pepper Phytophthora blight caused by Phytophthora capsici L. is the most destructive disease for reducing pepper yields in the world. Building up varietal resistance and induced resistance to the disease are of agricultural importance. In this paper, the disease resistance induced by salicylic acid (SA) against P. capsici were studied by using four hot pepper lines with different resistant abilities and one P. capsici strain with middle pathogenicity. Results show that SA could induce significantly the resistance of pepper seedlings to P. capsici, but CaC12, KH2PO4 and VAM couldn't. SA at a relative low concentration from 0.15 to 0.3 g L-1 had no antifungal activity in vitro against P. capsici. That means the disease resistant enhancement of the plants treated with SA is due to the induction effect, but not the antifungal effect of SA. About 1 to 5 days internal between SA-treatment and challenge inoculation was sufficient to induce the disease resistance of hot pepper. The resistance could remain more than 20 days after treatment with SA.

  4. Acid ceramidase in prostate cancer radiation therapy resistance and relapse

    Science.gov (United States)

    Cheng, Joseph C.

    Prostate tumor cell escape from ionizing radiation (IR)-induced killing can lead to disease progression and relapse. Sphingolipids such as ceramide and sphingosine 1-phosphate influence signal transduction pathways that regulate stress response in cancer cells. In particular, metabolism of apoptotic ceramide constitutes an important survival adaptation. Assessments of enzyme activity, mRNA, and protein demonstrated preferential upregulation of the ceramide deacylating enzyme acid ceramidase (AC) in irradiated cancer cells. Promoter-reporter and ChIP-qPCR assays revealed AC transcription by activator protein 1 (AP-1) is sensitive to pharmacological inhibition of de novo ceramide biosynthesis, identifying a protective feedback mechanism that mitigates the effects of IR-induced ceramide. Deregulation of c-Jun, in particular, induced marked radiosensitization in vitro and in vivo, which was rescued by ectopic AC over-expression. AC over-expression in prostate cancer clonogens surviving 80 Gray fractionated irradiation was associated with increased radioresistance and proliferation, suggesting a role in radiotherapy failure and relapse. Indeed, immunohistochemical analysis of human prostate cancer tissues revealed higher levels of AC after radiotherapy failure than therapy-naive adenocarcinoma, PIN, or benign tissues. By genetically downregulating AC with small interfering RNA (siRNA), we observed radiosensitization of cells using clonogenic and cytotoxicity assays. Finally, treatment with lysosomotropic small molecule inhibitors of AC, LCL385 or LCL521, induced prostate cancer xenograft radiosensitization and long-term suppression, suggesting AC is a tractable target for adjuvant radiotherapy.

  5. Acidic Barren Slope Profiling using Electrical Resistivity Imaging (ERI) at Ayer Hitam area Johor, Malaysia

    Science.gov (United States)

    Azhar, A. T. S.; Hazreek, Z. A. M.; Aziman, M.; Haimi, D. S.; Hafiz, Z. M.

    2016-04-01

    Recently, non-destructive method such as the electrical resistivity technique has become increasingly popular in engineering, environmental, mining and archeological studies nowadays. This method was popular in subsurface profiling due to its ability to replicate the images of the subsurface indirectly. The soil slope found in Batu Pahat, specifically in Ayer Hitam, is known to be problematic due to its barren condition. This location is believed to contain futile soil due to its difficulty in supporting the growth of vegetations. In the past, acidic barren slope assessment using non-destructive method was rarely being used due to several reasons related to the equipment and knowledge constraints. Hence, this study performed an electrical resistivity imaging using ABEM Terrameter LS in order to investigate the acidic barren slope conditions. Field data acquisition was based on Schlumberger and Wenner arrays while RES2DINV software was used to analyze and generate a 2-D model of the problematic subsurface profile. Based on electrical resistivity results, it was found that the acidic barren slope studied consists of two main zones representing residual soil (electrical resistivity value = 10 - 600 Ωm) and shale (electrical resistivity value = 20 - 2000 Ωm). The results of resistivity value were correlated with the physical mapping and the in situ mackintosh probe test for verification purposes. It was found that the maximum depth of the mackintosh probe test was 1.8 m due to its ground penetration limitation. However, the results of the resistivity section managed to achieve greater depth up to 40 m. Hence, the correlation between electrical resistivity and mackintosh probe results can only be performed at certain depth of the acidic barren slope profile in contrast with the physical mapping which able to define the whole section of the barren soil slope structure. Finally, a good match of electrical resistivity results calibrated with mackintosh and physical

  6. Effects of Boronizing Treatment on Corrosion Resistance of 65Mn Steel in two Acid Mediums

    Science.gov (United States)

    Wang, Hongyu; Zhao, Yufeng; Yuan, Xiaoming; Chen, Kangmin; Xu, Ruihua

    To explore the soil workability of rotary blade suitable for large tilling depth (over 20 cm) manufactured through boronizing treatment, this work focuses on the corrosion behavior of 65Mn steel after boronizing treatment in two acid mediums, i.e. the strong acidic medium that hydrochloric solution and the weak acidic that fertilizer-containing soil, and the comparison with existing technology of general rotary blade (lonnealing after overall quenching). The result shows that the corrosion resistance in the two acid mediums of 65Mn steel after boronizing treatment is remarkably improved. After 168 hours' corrosion in the hydrochloric acid solution, the weight loss of boronizing-status sample is only 27.9% of that of lonnealing-status sample. Moreover, there is no obvious weight loss in boronizing-status sample after 168 hours' corrosion in the fertilizer-containing soil, while the weight of lonnealing-status sample is lighter than the original weight after about 150 hours' corrosion. The improvement of the corrosion resistance lies in the significant reduction of the anodization speed in strong acid medium and the effective prevention of phosphorization reaction in weak acidic medium.

  7. Novel nickel resistance genes from the rhizosphere metagenome of plants adapted to acid mine drainage.

    Science.gov (United States)

    Mirete, Salvador; de Figueras, Carolina G; González-Pastor, Jose E

    2007-10-01

    Metal resistance determinants have traditionally been found in cultivated bacteria. To search for genes involved in nickel resistance, we analyzed the bacterial community of the rhizosphere of Erica andevalensis, an endemic heather which grows at the banks of the Tinto River, a naturally metal-enriched and extremely acidic environment in southwestern Spain. 16S rRNA gene sequence analysis of rhizosphere DNA revealed the presence of members of five phylogenetic groups of Bacteria and the two main groups of Archaea mostly associated with sites impacted by acid mine drainage (AMD). The diversity observed and the presence of heavy metals in the rhizosphere led us to construct and screen five different metagenomic libraries hosted in Escherichia coli for searching novel nickel resistance determinants. A total of 13 positive clones were detected and analyzed. Insights about their possible mechanisms of resistance were obtained from cellular nickel content and sequence similarities. Two clones encoded putative ABC transporter components, and a novel mechanism of metal efflux is suggested. In addition, a nickel hyperaccumulation mechanism is proposed for a clone encoding a serine O-acetyltransferase. Five clones encoded proteins similar to well-characterized proteins but not previously reported to be related to nickel resistance, and the remaining six clones encoded hypothetical or conserved hypothetical proteins of uncertain functions. This is the first report documenting nickel resistance genes recovered from the metagenome of an AMD environment. PMID:17675438

  8. Protecting Cell Walls from Binding Aluminum by Organic Acids Contributes to Aluminum Resistance

    Institute of Scientific and Technical Information of China (English)

    Ya-Ying Li; Yue-Jiao Zhang; Yuan Zhou; Jian-Li Yang; Shao-Jian Zheng

    2009-01-01

    Aluminum-induced secretion of organic acids from the root apex has been demonstrated to be one major AI resistance mechanism in plants. However, whether the organic acid concentration is high enough to detoxify AI in the growth medium is frequently questioned. The genotypes of Al-resistant wheat, Cassia tora L. and buckwheat secrete malate, citrate and oxalate, respectively. In the present study we found that at a 35% inhibition of root elongation, the AI activities in the solution were 10, 20, and 50 μM with the corresponding malate, citrate, and oxalate exudation at the rates of 15, 20 and 21 nmol/cm2 per 12 h, respectively, for the above three plant species. When exogenous organic acids were added to ameliorate Al toxicity, twofold and eightfold higher oxalate and malate concentrations were required to produce the equal effect by citrate. After the root apical cell walls were isolated and preincubated in 1 mM malate, oxalate or citrate solution overnight, the total amount of AI adsorbed to the cell walls all decreased significantly to a similar level, implying that these organic acids own an equal ability to protect the cell walls from binding AI. These findings suggest that protection of cell walls from binding Al by organic acids may contribute significantly to AI resistance.

  9. Crosslinked and Dyed Chitosan Fiber Presenting Enhanced Acid Resistance and Bioactivities

    Directory of Open Access Journals (Sweden)

    Xiao-Qiong Li

    2016-04-01

    Full Text Available The application of biodegradable chitosan fiber for healthy and hygienic textiles is limited due to its poor acid resistance in wet processing and poor antioxidant activity. In order to prepare chitosan fiber with good acid resistance and high antioxidant activity, chitosan fiber was first crosslinked by a water-soluble aziridine crosslinker, and then dyed with natural lac dye consisting of polyphenolic anthraquinone compounds. The main application conditions and crosslinking mechanism of the aziridine crosslinker, the adsorption mechanism and building-up property of lac dye on the crosslinked fiber, and the effects of crosslinking and dyeing on the antioxidant and antibacterial activities of chitosan fiber were studied. The crosslinked fiber exhibited greatly reduced weight loss in acidic solution, and possessed excellent acid resistance. Lac dye displayed a very high adsorption capability on the crosslinked fiber and a high utilization rate under weakly acidic medium. The Langmuir–Nernst isotherm was the best model to describe the adsorption behavior of lac dye, and Langmuir adsorption had great contribution to total adsorption. Lac dyeing imparted good antioxidant activity to chitosan fiber. Crosslinking and dyeing had no impact on the good inherent antibacterial activity of chitosan fiber.

  10. Overexpression of a soybean salicylic acid methyltransferase gene confers resistance to soybean cyst nematode.

    Science.gov (United States)

    Lin, Jingyu; Mazarei, Mitra; Zhao, Nan; Zhu, Junwei J; Zhuang, Xiaofeng; Liu, Wusheng; Pantalone, Vincent R; Arelli, Prakash R; Stewart, Charles N; Chen, Feng

    2013-12-01

    Salicylic acid plays a critical role in activating plant defence responses after pathogen attack. Salicylic acid methyltransferase (SAMT) modulates the level of salicylic acid by converting salicylic acid to methyl salicylate. Here, we report that a SAMT gene from soybean (GmSAMT1) plays a role in soybean defence against soybean cyst nematode (Heterodera glycines Ichinohe, SCN). GmSAMT1 was identified as a candidate SCN defence-related gene in our previous analysis of soybean defence against SCN using GeneChip microarray experiments. The current study started with the isolation of the full-length cDNAs of GmSAMT1 from a SCN-resistant soybean line and from a SCN-susceptible soybean line. The two cDNAs encode proteins of identical sequences. The GmSAMT1 cDNA was expressed in Escherichia coli. Using in vitro enzyme assays, E. coli-expressed GmSAMT1 was confirmed to function as salicylic acid methyltransferase. The apparent Km value of GmSAMT1 for salicylic acid was approximately 46 μM. To determine the role of GmSAMT1 in soybean defence against SCN, transgenic hairy roots overexpressing GmSAMT1 were produced and tested for SCN resistance. Overexpression of GmSAMT1 in SCN-susceptible backgrounds significantly reduced the development of SCN, indicating that overexpression of GmSAMT1 in the transgenic hairy root system could confer resistance to SCN. Overexpression of GmSAMT1 in transgenic hairy roots was also found to affect the expression of selected genes involved in salicylic acid biosynthesis and salicylic acid signal transduction.

  11. Effect of Post Heat Treatment on Corrosion Resistance of Phytic Acid Conversion Coated Magnesium

    Institute of Scientific and Technical Information of China (English)

    R.K. Gupta; K. Mensah-Darkwa; D. Kumar

    2013-01-01

    An environment friendly chemical conversion coating for magnesium was obtained by using a phytic acid solution.The effect of post-coating 1heat treatment on the microstructures and corrosion properties of phytic acid conversion coated magnesium was investigated.It was observed that the microstructure and corrosion resistive properties were improved for the heat treated samples.The corrosion current density for bare magnesium,phytic acid conversion coated magnesium,and post-coating heat treated magnesium was calculated to be 2.48 × 10-5,1.18 × 10-6,and 9.27 × 10-7 A/cm2,respectively.The lowest corrosion current density for the heat treated sample indicated its highest corrosion resistive effect for the magnesium.The maximum corrosion protective nature of the heat treated sample was further confirmed by the largest value of impedance in electrochemical impedance spectroscopy studies.

  12. Free fatty acid-induced hepatic insulin resistance is attenuated following lifestyle intervention in obese individuals with impaired glucose tolerance

    DEFF Research Database (Denmark)

    Haus, Jacob M; Solomon, Thomas; Marchetti, Christine M;

    2010-01-01

    The objective of the study was to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans.......The objective of the study was to examine the effects of an exercise/diet lifestyle intervention on free fatty acid (FFA)-induced hepatic insulin resistance in obese humans....

  13. Gene-related strain variation of Staphylococcus aureus for homologous resistance response to acid stress.

    Science.gov (United States)

    Lee, Soomin; Ahn, Sooyeon; Lee, Heeyoung; Kim, Won-Il; Kim, Hwang-Yong; Ryu, Jae-Gee; Kim, Se-Ri; Choi, Kyoung-Hee; Yoon, Yohan

    2014-10-01

    This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation. PMID:25285500

  14. Improved volatile fatty acids anaerobic production from waste activated sludge by pH regulation: Alkaline or neutral pH?

    Science.gov (United States)

    Ma, Huijun; Chen, Xingchun; Liu, He; Liu, Hongbo; Fu, Bo

    2016-02-01

    In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46mg COD/gVS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14mg COD/gVS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process. PMID:26652215

  15. Influence of Block Copolymer on Formation and Acid Resistant Properties of Hybrid CaCO3 Particles

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-dong; HU Qiao-ling; ZHAO Shi-fang; SHEN Jia-cong

    2009-01-01

    Block copolymer polystyrene-b-poly(acrylic acid)(PS-b-PAA) was used as structural template for the synthesis of CaCO3 microparticles. Through this procedure, acid resistant hybrid CaCO3 micro-spheres were obtained. Acid resistant properties of this type of hybrid CaCO3 were studied. Size mea-surement shows that the acid resistant properties of the hybrid particles are different in different solutions, such as HCI, EDTA, and H2SO4 solutions.

  16. Distribution of antimicrobial-resistant lactic acid bacteria in natural cheese in Japan.

    Science.gov (United States)

    Ishihara, Kanako; Nakajima, Kumiko; Kishimoto, Satoko; Atarashi, Fumiaki; Muramatsu, Yasukazu; Hotta, Akitoyo; Ishii, Satomi; Takeda, Yasuyuki; Kikuchi, Masanori; Tamura, Yutaka

    2013-10-01

    To determine and compare the extent of contamination caused by antimicrobial-resistant lactic acid bacteria (LAB) in imported and domestic natural cheeses on the Japanese market, LAB were isolated using deMan, Rogosa and Sharpe (MRS) agar and MRS agar supplemented with six antimicrobials. From 38 imported and 24 Japanese cheeses, 409 LAB isolates were obtained and their antimicrobial resistance was tested. The percentage of LAB resistant to dihydrostreptomycin, erythromycin, and/or oxytetracycline isolated from imported cheeses (42.1%) was significantly higher than that of LAB resistant to dihydrostreptomycin or oxytetracycline from cheeses produced in Japan (16.7%; P=0.04). Antimicrobial resistance genes were detected in Enterococcus faecalis (tetL, tetM, and ermB; tetL and ermB; tetM) E. faecium (tetM), Lactococcus lactis (tetS), Lactobacillus (Lb.), casei/paracasei (tetM or tetW), and Lb. rhamnosus (ermB) isolated from seven imported cheeses. Moreover, these E. faecalis isolates were able to transfer antimicrobial resistance gene(s). Although antimicrobial resistance genes were not detected in any LAB isolates from Japanese cheeses, Lb. casei/paracasei and Lb. coryniformis isolates from a Japanese farm-made cheese were resistant to oxytetracycline (minimal inhibitory concentration [MIC], 32 µg/mL). Leuconostoc isolates from three Japanese farm-made cheeses were also resistant to dihydrostreptomycin (MIC, 32 to >512 µg/mL). In conclusion, the present study demonstrated contamination with antimicrobial-resistant LAB in imported and Japanese farm-made cheeses on the Japanese market, but not in Japanese commercial cheeses.

  17. Efficacy of phosphatidic acid ingestion on lean body mass, muscle thickness and strength gains in resistance-trained men

    OpenAIRE

    Hoffman Jay R; Stout Jeffrey R; Williams David R; Wells Adam J; Fragala Maren S; Mangine Gerald T; Gonzalez Adam M; Emerson Nadia S; McCormack William P; Scanlon Tyler C; Purpura Martin; Jäger Ralf

    2012-01-01

    Abstract Background Phosphatidic acid (PA) has been reported to activate the mammalian target of rapamycin (mTOR) signaling pathway and is thought to enhance the anabolic effects of resistance training. The purpose of this pilot study was to examine if oral phosphatidic acid administration can enhance strength, muscle thickness and lean tissue accruement during an 8-week resistance training program. Methods Sixteen resistance-trained men were randomly assigned to a group that either consumed ...

  18. Withaferin A protects against palmitic acid-induced endothelial insulin resistance and dysfunction through suppression of oxidative stress and inflammation

    OpenAIRE

    Kalaivani Batumalaie; Muhammad Arif Amin; Dharmani Devi Murugan; Munavvar Zubaid Abdul Sattar; Nor Azizan Abdullah

    2016-01-01

    Activation of inflammatory pathways via reactive oxygen species (ROS) by free fatty acids (FFA) in obesity gives rise to insulin resistance and endothelial dysfunction. Withaferin A (WA), possesses both antioxidant and anti-inflammatory properties and therefore would be a good strategy to suppress palmitic acid (PA)-induced oxidative stress and inflammation and hence, insulin resistance and dysfunction in the endothelium. Effect of WA on PA-induced insulin resistance in human umbilical vein e...

  19. Evolution of internal resistance during formation of flooded lead-acid batteries

    Science.gov (United States)

    White, Chris; Deveau, Justin; Swan, Lukas G.

    2016-09-01

    This study employs experimental techniques to measure the changing internal resistance of flooded, flat-plate lead-acid batteries during container formation, revealing a novel indicator of formation completeness. In order to measure internal resistance during formation, d.c. current pulses are superimposed over the constant formation current at set intervals, while change in voltage is measured. The resulting "pulsed" internal resistance is divided into ohmic and interfacial components by measuring the ohmic resistance with short d.c. pulses as well as with a.c. injection. Various constant-current container formations are carried out using different current levels, plate thicknesses, and pulsing techniques, yielding an array of resistance trends which are explained using Butler-Volmer kinetic theory. Ohmic and interfacial resistance trends are shown both theoretically and experimentally to eventually decay to a predictable steady-state value as the formation proceeds, suggesting that this internal resistance method can be used to detect the completion of the formation. The same principles are shown to apply to recharge cycles as well, but with potentially limited practical implications in comparison to formation.

  20. ANTIBIOTIC RESISTANCE IN LACTIC ACID BACTERIA ISOLATED FROM FERMENTED DAIRY PRODUCTS AND BOZA

    Directory of Open Access Journals (Sweden)

    Gamze Başbülbül

    2015-06-01

    Full Text Available In this study, the resistance of 83 strains of lactic acid bacteria isolated from Turkish cheese, yogurt, kefir and boza samples to 6 antibiotics (gentamicin, tetracycline, chloramphenicol, erythromycin, vancomycin and ciprofloxacin was evaluated. The 83 isolates were identified by 16S rRNA gene sequencing and according to BLAST comparisons with sequences in the data banks, those strains showing the highest similarities with the isolates were Enterococcus faecium (10, Lactococcus lactis subsp. Lactis (10, Lactobacillus fermentum (6, Lactobacillus plantarum (6, Lactobacillus coryniformis (7, Lactobacillus casei (13, Leuconostoc mesenteroides (14, Pediococcus pentosaceus (10, Weisella confusa (7. Antimicrobial resistance of strains to 6 antibiotics was determined using the agar dilution method. The antibiotic resistance among all the isolates was detected against chloramphenicol (31,3 % of the isolates, tetracycline (30,1 %, erythromycin (2,4 %, ciprofloxacin (2,41%, vancomycin (73,5 %, intrinsic resistance. Overall 19,3 % of the isolates showed resistance against multiple antibiotics. Antibiotic resistance genes were studied by PCR and the following genes were detected; tet(M gene in Lactobacillus fermentum (1, Lactobacillus plantarum (1, Pediococcus pentosaceus (5, Enterococcus faecium (2, Weisella confusa (4 and the vancomycin resistance gene van(A in one Weisella confusa strain.

  1. Precision microbiome reconstitution restores bile acid mediated resistance to Clostridium difficile

    Science.gov (United States)

    Buffie, Charlie G.; Bucci, Vanni; Stein, Richard R.; McKenney, Peter T.; Ling, Lilan; Gobourne, Asia; No, Daniel; Liu, Hui; Kinnebrew, Melissa; Viale, Agnes; Littmann, Eric; van den Brink, Marcel R. M.; Jenq, Robert R.; Taur, Ying; Sander, Chris; Cross, Justin R.; Toussaint, Nora C.; Xavier, Joao B.; Pamer, Eric G.

    2015-01-01

    The gastrointestinal tracts of mammals are colonized by hundreds of microbial species that contribute to health, including colonization resistance against intestinal pathogens. Many antibiotics destroy intestinal microbial communities and increase susceptibility to intestinal pathogens. Among these, Clostridium difficile, a major cause of antibiotic-induced diarrhoea, greatly increases morbidity and mortality in hospitalized patients. Which intestinal bacteria provide resistance to C. difficile infection and their in vivo inhibitory mechanisms remain unclear. Here we correlate loss of specific bacterial taxa with development of infection, by treating mice with different antibiotics that result in distinct microbiota changes and lead to varied susceptibility to C. difficile. Mathematical modelling augmented by analyses of the microbiota of hospitalized patients identifies resistance-associated bacteria common to mice and humans. Using these platforms, we determine that Clostridium scindens, a bile acid 7α-dehydroxylating intestinal bacterium, is associated with resistance to C. difficile infection and, upon administration, enhances resistance to infection in a secondary bile acid dependent fashion. Using a workflow involving mouse models, clinical studies, metagenomic analyses, and mathematical modelling, we identify a probiotic candidate that corrects a clinically relevant microbiome deficiency. These findings have implications for the rational design of targeted antimicrobials as well as microbiome-based diagnostics and therapeutics for individuals at risk of C. difficile infection.

  2. Ascorbic acid accumulates as a defense response to Turnip mosaic virus in resistant Brassica rapa cultivars.

    Science.gov (United States)

    Fujiwara, Ayaka; Togawa, Satoko; Hikawa, Takahiro; Matsuura, Hideyuki; Masuta, Chikara; Inukai, Tsuyoshi

    2016-07-01

    We initially observed that Brassica rapa cultivars containing the Turnip mosaic virus (TuMV) resistance gene, Rnt1-1, accumulated a high level of endogenous ascorbic acid (AS) and dehydroascobic acid (DHA) when infected with TuMV. We here hypothesized a possible contribution of an elevated level of AS+DHA (TAA) to the Rnt1-1-mediated resistance, and conducted a series of experiments using B. rapa and Arabidopsis plants. The application of l-galactose (the key substrate in AS synthesis) to a susceptible cultivar could increase the TAA level ~2-fold, and simultaneously lead to some degree of enhanced viral resistance. To confirm some positive correlation between TAA levels and viral resistance, we analyzed two Arabidopsis knockout mutants (ao and vtc1) in the AS pathways; the TAA levels were significantly increased and decreased in ao and vtc1 plants, respectively. While the ao plants showed enhanced resistance to TuMV, vtc1 plants were more susceptible than the control, supporting our hypothesis. When we analyzed the expression profiles of the genes involved in the AS pathways upon TuMV infection, we found that the observed TAA increase was mainly brought about by the reduction of AS oxidation and activation of AS recycling. We then investigated the secondary signals that regulate endogenous TAA levels in response to viral infection, and found that jasmonic acid (JA) might play an important role in TAA accumulation. In conclusion, we reason that the elevated TAA accumulation in B. rapa plants would be at least partly mediated by the JA-dependent signaling pathway and may significantly contribute to viral resistance. PMID:27255930

  3. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. PMID:27058913

  4. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction.

  5. Effects of Dietary n-3 Fatty Acids on Hepatic and Peripheral Insulin Sensitivity in Insulin-Resistant Humans

    OpenAIRE

    Lalia, Antigoni Z; Johnson, Matthew L; Jensen, Michael D.; Hames, Kazanna C.; Port, John D.; Lanza, Ian R.

    2015-01-01

    OBJECTIVE Dietary n-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), prevent insulin resistance and stimulate mitochondrial biogenesis in rodents, but the findings of translational studies in humans are thus far ambiguous. The aim of this study was to evaluate the influence of EPA and DHA on insulin sensitivity, insulin secretion, and muscle mitochondrial function in insulin-resistant, nondiabetic humans using a robust study design and gold-...

  6. Omega 3 fatty acids chemosensitize multidrug resistant colon cancer cells by down-regulating cholesterol synthesis and altering detergent resistant membranes composition

    OpenAIRE

    Gelsomino, Giada; Corsetto, Paola A.; Campia, Ivana; Montorfano, Gigliola; Kopecka, Joanna; Castella, Barbara; Gazzano, Elena; Ghigo, Dario; Rizzo, Angela M; Riganti, Chiara

    2013-01-01

    Background The activity of P-glycoprotein (Pgp) and multidrug resistance related protein 1 (MRP1), two membrane transporters involved in multidrug resistance of colon cancer, is increased by high amounts of cholesterol in plasma membrane and detergent resistant membranes (DRMs). It has never been investigated whether omega 3 polyunsatured fatty acids (PUFAs), which modulate cholesterol homeostasis in dyslipidemic syndromes and have chemopreventive effects in colon cancer, may affect the respo...

  7. Meropenem-clavulanic acid has high in vitro activity against multidrug-resistant Mycobacterium tuberculosis.

    Science.gov (United States)

    Davies Forsman, L; Giske, C G; Bruchfeld, J; Schön, T; Juréen, P; Ängeby, K

    2015-01-01

    We investigated the activity of meropenem-clavulanic acid (MEM-CLA) against 68 Mycobacterium tuberculosis isolates. We included predominantly multi- and extensively drug-resistant tuberculosis (MDR/XDR-TB) isolates, since the activity of MEM-CLA for resistant isolates has previously not been studied extensively. Using Middlebrook 7H10 medium, all but four isolates showed an MIC distribution of 0.125 to 2 mg/liter for MEM-CLA, below the non-species-related breakpoint for MEM of 2 mg/liter defined by EUCAST. MEM-CLA is a potential treatment option for MDR/XDR-TB.

  8. Biodegradation and reversible inhibitory impact of sulfamethoxazole on the utilization of volatile fatty acids during anaerobic treatment of pharmaceutical industry wastewater

    International Nuclear Information System (INIS)

    This study evaluated the chronic impact and biodegradability of sulfamethoxazole under anaerobic conditions. For this purpose, a lab-scale anaerobic sequencing batch reactor was operated in a sequence of different phases with gradually increasing sulfamethoxazole doses of 1 to 45 mg/L. Conventional parameters, such as COD, VFA, and methane generation, were monitored with corresponding antimicrobial concentrations in the reactor and the methanogenic activity of the sludge. The results revealed that anaerobic treatment was suitable for pharmaceutical industry wastewater with concentrations of up to 40 mg/L of sulfamethoxazole. Higher levels exerted toxic effects on the microbial community under anaerobic conditions, causing the inhibition of substrate/COD utilization and biogas generation and leading to a total collapse of the reactor. The adverse long-term impact was quite variable for fermentative bacteria and methanogenic achaea fractions of the microbial community based on changes inflicted on the composition of the residual organic substrate and mRNA expression of the key enzymes. - Highlights: • Chronic impact of sulfamethoxazole was lethal at 45 mg/L on the microbial community. • Sulfamethoxazole was highly biodegradable under anaerobic conditions. • While the COD removal stopped, the sorption of sulfamethoxazole into the sludge increased. • Sulfamethoxazole has a reversible inhibitory effect on acetoclastic methanogens

  9. Biodegradation and reversible inhibitory impact of sulfamethoxazole on the utilization of volatile fatty acids during anaerobic treatment of pharmaceutical industry wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Cetecioglu, Zeynep, E-mail: cetecioglu@itu.edu.tr [Istanbul Technical University, Environmental Engineering Department, 34469 Maslak, Istanbul (Turkey); Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona (Spain); Ince, Bahar [Bogazici University, Institute of Environmental Sciences, Rumelihisarustu - Bebek, 34342 Istanbul (Turkey); Gros, Meritxell; Rodriguez-Mozaz, Sara; Barceló, Damia [Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona (Spain); Ince, Orhan; Orhon, Derin [Istanbul Technical University, Environmental Engineering Department, 34469 Maslak, Istanbul (Turkey)

    2015-12-01

    This study evaluated the chronic impact and biodegradability of sulfamethoxazole under anaerobic conditions. For this purpose, a lab-scale anaerobic sequencing batch reactor was operated in a sequence of different phases with gradually increasing sulfamethoxazole doses of 1 to 45 mg/L. Conventional parameters, such as COD, VFA, and methane generation, were monitored with corresponding antimicrobial concentrations in the reactor and the methanogenic activity of the sludge. The results revealed that anaerobic treatment was suitable for pharmaceutical industry wastewater with concentrations of up to 40 mg/L of sulfamethoxazole. Higher levels exerted toxic effects on the microbial community under anaerobic conditions, causing the inhibition of substrate/COD utilization and biogas generation and leading to a total collapse of the reactor. The adverse long-term impact was quite variable for fermentative bacteria and methanogenic achaea fractions of the microbial community based on changes inflicted on the composition of the residual organic substrate and mRNA expression of the key enzymes. - Highlights: • Chronic impact of sulfamethoxazole was lethal at 45 mg/L on the microbial community. • Sulfamethoxazole was highly biodegradable under anaerobic conditions. • While the COD removal stopped, the sorption of sulfamethoxazole into the sludge increased. • Sulfamethoxazole has a reversible inhibitory effect on acetoclastic methanogens.

  10. A "Whirly" transcription factor is required for salicylic acid-dependent disease resistance in Arabidopsis.

    Science.gov (United States)

    Desveaux, Darrell; Subramaniam, Rajagopal; Després, Charles; Mess, Jean-Nicholas; Lévesque, Caroline; Fobert, Pierre R; Dangl, Jeffery L; Brisson, Normand

    2004-02-01

    Transcriptional reprogramming is critical for plant disease resistance responses; its global control is not well understood. Salicylic acid (SA) can induce plant defense gene expression and a long-lasting disease resistance state called systemic acquired resistance (SAR). Plant-specific "Whirly" DNA binding proteins were previously implicated in defense gene regulation. We demonstrate that the potato StWhy1 protein is a transcriptional activator of genes containing the PBF2 binding PB promoter element. DNA binding activity of AtWhy1, the Arabidopsis StWhy1 ortholog, is induced by SA and is required for both SA-dependent disease resistance and SA-induced expression of an SAR response gene. AtWhy1 is required for both full basal and specific disease resistance responses. The transcription factor-associated protein NPR1 is also required for SAR. Surprisingly, AtWhy1 activation by SA is NPR1 independent, suggesting that AtWhy1 works in conjunction with NPR1 to transduce the SA signal. Our analysis of AtWhy1 adds a critical component to the SA-dependent plant disease resistance response. PMID:14960277

  11. Preparation of acid-resistant magnetic adsorbent for effective removal of p-nitrophenol

    Institute of Scientific and Technical Information of China (English)

    Qing Zhou; Zhe Qin Li; Chen Dong Shuang; Ai Min Li; Meng Qiao Wang; Man Cheng Zhang

    2012-01-01

    Bilayer-silane-coated Fe3O4 nanoparticles with inner layer of tetraethoxy silane (TEOS) and outer layer of vinyltriethoxysilane (VTEO) were generated to enhance their acid resistance.These nanoparticles were copolymerized with vinylbenzyl chloride (VBC)using suspension polymerization,and then post-crosslinked.The resulting hypercrosslinked magnetic resin M150 presented specific bimodal property with large specific surface area of 1109 m2/g.It exhibited more excellent adsorption capacity of pnitrophenol compared to another two magnetic adsorbents Q 150 and MIEX(R).Moreover,the acid stable property of the magnetite in M150 extended its application at low pH value.

  12. Myocardial fatty acid metabolism and lipotoxicity in the setting of insulin resistance.

    Science.gov (United States)

    Kok, Bernard P C; Brindley, David N

    2012-10-01

    Management of diabetes and insulin resistance in the setting of cardiovascular disease has become an important issue in an increasingly obese society. Besides the development of hypertension and buildup of atherosclerotic plaques, the derangement of fatty acid and lipid metabolism in the heart plays an important role in promoting cardiac dysfunction and oxidative stress. This review discusses the mechanisms by which metabolic inflexibility in the use of fatty acids as the preferred cardiac substrate in diabetes produces detrimental effects on mechanical efficiency, mitochondrial function, and recovery from ischemia. Lipid accumulation and the consequences of toxic lipid metabolites are also discussed. PMID:22999246

  13. Comparative Studies of Alternative Anaerobic Digestion Technologies

    OpenAIRE

    Inman, David C.

    2004-01-01

    Washington D.C. Water and Sewage Authority is planning to construct a new anaerobic digestion facility at its Blue Plains WWTP by 2008. The research conducted in this study is to aid the designers of this facility by evaluating alternative digestion technologies. Alternative anaerobic digestion technologies include thermophilic, acid/gas phased, and temperature phased digestion. In order to evaluate the relative merits of each, a year long study evaluated the performance of bench scale dig...

  14. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  15. Valproic Acid Downregulates the Expression of MGMT and Sensitizes Temozolomide-Resistant Glioma Cells

    OpenAIRE

    Chung Heon Ryu; Wan Soo Yoon; Kwang Ywel Park; Seong Muk Kim; Jung Yeon Lim; Ji Sun Woo; Chang Hyun Jeong; Yun Hou; Sin-Soo Jeun

    2012-01-01

    Temozolomide (TMZ) has become a key therapeutic agent in patients with malignant gliomas; however, its survival benefit remains unsatisfactory. Valproic acid (VPA) has emerged as an anticancer drug via inhibition of histone deacetylases (HDACs), but the therapeutic advantages of a combination with VPA and TMZ remain poorly understood. The main aim of the present study was to determine whether an antitumor effect could be potentiated by a combination of VPA and TMZ, especially in TMZ-resistant...

  16. Induction of Systemic Resistance of Benzothiadiazole and Humic Acid in Soybean Plants Against Fusarium Wilt Disease

    OpenAIRE

    Montaser Fawzy ABDEL-MONAIM; Mamdoh Ewis ISMAIL; Morsy, Kadry Mohamed

    2011-01-01

    The ability of benzothiadiazole (BTH) and/or humic acid (HA) used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Alone and in combination the inducers were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations (Minia and New Valley governorates). The test...

  17. Microstructure and corrosion resistance of phytic acid conversion coatings for magnesium alloy

    International Nuclear Information System (INIS)

    In this paper, a new innoxious and pollution-free chemical protective coating for magnesium alloys, phytic acid conversion coating, was prepared. The conversion coatings are found to have high cover ratio and no cracks are found by atomic force microscopes (AFM) and scanning electron microscopy (SEM). The main elements of the conversion coatings are Mg, Al, O, P and C by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The chemical state of the elements in the coatings was also investigated by Fourier transform infrared spectroscopy (FTIR). AES depth profile analysis suggests that the thickness of the conversion coating is about 340 nm. The corrosion resistance of the coatings was evaluated by polarization curves. The results indicate that the corrosion resistance for the conversion coated AZ91D magnesium alloys in 3.5% NaCl solution increases markedly. The mechanisms of corrosion resistance and coatings formation are also discussed.

  18. Microstructure and corrosion resistance of phytic acid conversion coatings for magnesium alloy

    Science.gov (United States)

    Cui, Xiufang; Li, Qingfen; Li, Ying; Wang, Fuhui; Jin, Guo; Ding, Minghui

    2008-12-01

    In this paper, a new innoxious and pollution-free chemical protective coating for magnesium alloys, phytic acid conversion coating, was prepared. The conversion coatings are found to have high cover ratio and no cracks are found by atomic force microscopes (AFM) and scanning electron microscopy (SEM). The main elements of the conversion coatings are Mg, Al, O, P and C by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The chemical state of the elements in the coatings was also investigated by Fourier transform infrared spectroscopy (FTIR). AES depth profile analysis suggests that the thickness of the conversion coating is about 340 nm. The corrosion resistance of the coatings was evaluated by polarization curves. The results indicate that the corrosion resistance for the conversion coated AZ91D magnesium alloys in 3.5% NaCl solution increases markedly. The mechanisms of corrosion resistance and coatings formation are also discussed.

  19. Microstructure and corrosion resistance of phytic acid conversion coatings for magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cui Xiufang [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li Qingfen [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Li Ying; Wang Fuhui [State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Jin Guo [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)], E-mail: jg97721@yahoo.com.cn; Ding Minghui [School of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2008-12-30

    In this paper, a new innoxious and pollution-free chemical protective coating for magnesium alloys, phytic acid conversion coating, was prepared. The conversion coatings are found to have high cover ratio and no cracks are found by atomic force microscopes (AFM) and scanning electron microscopy (SEM). The main elements of the conversion coatings are Mg, Al, O, P and C by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The chemical state of the elements in the coatings was also investigated by Fourier transform infrared spectroscopy (FTIR). AES depth profile analysis suggests that the thickness of the conversion coating is about 340 nm. The corrosion resistance of the coatings was evaluated by polarization curves. The results indicate that the corrosion resistance for the conversion coated AZ91D magnesium alloys in 3.5% NaCl solution increases markedly. The mechanisms of corrosion resistance and coatings formation are also discussed.

  20. Gambogic acid inhibits growth, induces apoptosis, and overcomes drug resistance in human colorectal cancer cells.

    Science.gov (United States)

    Wen, Chuangyu; Huang, Lanlan; Chen, Junxiong; Lin, Mengmeng; Li, Wen; Lu, Biyan; Rutnam, Zina Jeyapalan; Iwamoto, Aikichi; Wang, Zhongyang; Yang, Xiangling; Liu, Huanliang

    2015-11-01

    The emergence of chemoresistance is a major limitation of colorectal cancer (CRC) therapies and novel biologically based therapies are urgently needed. Natural products represent a novel potential anticancer therapy. Gambogic acid (GA), a small molecule derived from Garcinia hanburyi Hook. f., has been demonstrated to be highly cytotoxic to several types of cancer cells and have low toxicity to the hematopoietic system. However, the potential role of GA in colorectal cancer and its ability to overcome the chemotherapeutic resistance in CRC cells have not been well studied. In the present study, we showed that GA directly inhibited proliferation and induced apoptosis in both 5-fluorouracil (5-FU) sensitive and 5-FU resistant colorectal cancer cells; induced apoptosis via activating JNK signaling pathway. The data, therefore, suggested an alternative strategy to overcome 5-FU resistance in CRC and that GA could be a promising medicinal compound for colorectal cancer therapy. PMID:26397804

  1. Antibiotic resistance of lactic acid bacteria isolated from dry-fermented sausages.

    Science.gov (United States)

    Fraqueza, Maria João

    2015-11-01

    Dry-fermented sausages are meat products highly valued by many consumers. Manufacturing process involves fermentation driven by natural microbiota or intentionally added starter cultures and further drying. The most relevant fermentative microbiota is lactic acid bacteria (LAB) such as Lactobacillus, Pediococcus and Enterococcus, producing mainly lactate and contributing to product preservation. The great diversity of LAB in dry-fermented sausages is linked to manufacturing practices. Indigenous starters development is considered to be a very promising field, because it allows for high sanitary and sensorial quality of sausage production. LAB have a long history of safe use in fermented food, however, since they are present in human gastrointestinal tract, and are also intentionally added to the diet, concerns have been raised about the antimicrobial resistance in these beneficial bacteria. In fact, the food chain has been recognized as one of the key routes of antimicrobial resistance transmission from animal to human bacterial populations. The World Health Organization 2014 report on global surveillance of antimicrobial resistance reveals that this issue is no longer a future prediction, since evidences establish a link between the antimicrobial drugs use in food-producing animals and the emergence of resistance among common pathogens. This poses a risk to the treatment of nosocomial and community-acquired infections. This review describes the possible sources and transmission routes of antibiotic resistant LAB of dry-fermented sausages, presenting LAB antibiotic resistance profile and related genetic determinants. Whenever LAB are used as starters in dry-fermented sausages processing, safety concerns regarding antimicrobial resistance should be addressed since antibiotic resistant genes could be mobilized and transferred to other bacteria.

  2. Adipose tissue fatty acid chain length and mono-unsaturation increases with obesity and insulin resistance

    Science.gov (United States)

    Yew Tan, Chong; Virtue, Samuel; Murfitt, Steven; Robert, Lee D.; Phua, Yi Hui; Dale, Martin; Griffin, Julian L.; Tinahones, Francisco; Scherer, Philipp E.; Vidal-Puig, Antonio

    2015-01-01

    The non-essential fatty acids, C18:1n9, C16:0, C16:1n7, C18:0 and C18:1n7 account for over 75% of fatty acids in white adipose (WAT) triacylglycerol (TAG). The relative composition of these fatty acids (FA) is influenced by the desaturases, SCD1-4 and the elongase, ELOVL6. In knock-out models, loss of SCD1 or ELOVL6 results in reduced Δ9 desaturated and reduced 18-carbon non-essential FA respectively. Both Elovl6 KO and SCD1 KO mice exhibit improved insulin sensitivity. Here we describe the relationship between WAT TAG composition in obese mouse models and obese humans stratified for insulin resistance. In mouse models with increasing obesity and insulin resistance, there was an increase in scWAT Δ9 desaturated FAs (SCD ratio) and FAs with 18-carbons (Elovl6 ratio) in mice. Data from mouse models discordant for obesity and insulin resistance (AKT2 KO, Adiponectin aP2-transgenic), suggested that scWAT TAG Elovl6 ratio was associated with insulin sensitivity, whereas SCD1 ratio was associated with fat mass. In humans, a greater SCD1 and Elovl6 ratio was found in metabolically more harmful visceral adipose tissue when compared to subcutaneous adipose tissue. PMID:26679101

  3. Priming of plant resistance by natural compounds. Hexanoic acid as a model

    Directory of Open Access Journals (Sweden)

    Paz eAranega Bou

    2014-10-01

    Full Text Available Some alternative control strategies of currently emerging plant diseases are based on the use of resistance inducers. This review highlights the recent advances made in the characterization of natural compounds that induce resistance by a priming mechanism. These include vitamins, chitosans, oligogalacturonides, volatile organic compounds, azelaic and pipecolic acid, among others. Overall, other than providing novel disease control strategies that meet environmental regulations, natural priming agents are valuable tools to help unravel the complex mechanisms underlying the induced resistance phenomenon. The data presented in this review reflect the novel contributions made from studying these natural plant inducers, with special emphasis placed on hexanoic acid (Hx, proposed herein as a model tool for this research field. Hx is a potent natural priming agent of proven efficiency in a wide range of host plants and pathogens. It can early activate broad-spectrum defenses by inducing callose deposition and the SA and JA pathways. Later it can prime pathogen-specific responses according to the pathogen’s lifestyle. Interestingly, Hx primes redox-related genes to produce an anti-oxidant protective effect, which might be critical for limiting the infection of necrotrophs. Our Hx-induced resistance (Hx-IR findings also strongly suggest that it is an attractive tool for the molecular characterization of the plant alarmed state, with the added advantage of it being a natural compound.

  4. Enhanced disease susceptibility 1 and salicylic acid act redundantly to regulate resistance gene-mediated signaling.

    Directory of Open Access Journals (Sweden)

    Srivathsa C Venugopal

    2009-07-01

    Full Text Available Resistance (R protein-associated pathways are well known to participate in defense against a variety of microbial pathogens. Salicylic acid (SA and its associated proteinaceous signaling components, including enhanced disease susceptibility 1 (EDS1, non-race-specific disease resistance 1 (NDR1, phytoalexin deficient 4 (PAD4, senescence associated gene 101 (SAG101, and EDS5, have been identified as components of resistance derived from many R proteins. Here, we show that EDS1 and SA fulfill redundant functions in defense signaling mediated by R proteins, which were thought to function independent of EDS1 and/or SA. Simultaneous mutations in EDS1 and the SA-synthesizing enzyme SID2 compromised hypersensitive response and/or resistance mediated by R proteins that contain coiled coil domains at their N-terminal ends. Furthermore, the expression of R genes and the associated defense signaling induced in response to a reduction in the level of oleic acid were also suppressed by compromising SA biosynthesis in the eds1 mutant background. The functional redundancy with SA was specific to EDS1. Results presented here redefine our understanding of the roles of EDS1 and SA in plant defense.

  5. Enhanced disease susceptibility 1 and salicylic acid act redundantly to regulate resistance gene-mediated signaling.

    Science.gov (United States)

    Venugopal, Srivathsa C; Jeong, Rae-Dong; Mandal, Mihir K; Zhu, Shifeng; Chandra-Shekara, A C; Xia, Ye; Hersh, Matthew; Stromberg, Arnold J; Navarre, DuRoy; Kachroo, Aardra; Kachroo, Pradeep

    2009-07-01

    Resistance (R) protein-associated pathways are well known to participate in defense against a variety of microbial pathogens. Salicylic acid (SA) and its associated proteinaceous signaling components, including enhanced disease susceptibility 1 (EDS1), non-race-specific disease resistance 1 (NDR1), phytoalexin deficient 4 (PAD4), senescence associated gene 101 (SAG101), and EDS5, have been identified as components of resistance derived from many R proteins. Here, we show that EDS1 and SA fulfill redundant functions in defense signaling mediated by R proteins, which were thought to function independent of EDS1 and/or SA. Simultaneous mutations in EDS1 and the SA-synthesizing enzyme SID2 compromised hypersensitive response and/or resistance mediated by R proteins that contain coiled coil domains at their N-terminal ends. Furthermore, the expression of R genes and the associated defense signaling induced in response to a reduction in the level of oleic acid were also suppressed by compromising SA biosynthesis in the eds1 mutant background. The functional redundancy with SA was specific to EDS1. Results presented here redefine our understanding of the roles of EDS1 and SA in plant defense.

  6. Isoniazid inhibition of mycolic acid synthesis by cell extracts of sensitive and resistant strains of Mycobacterium aurum.

    OpenAIRE

    Quémard, A; Lacave, C; Lanéelle, G

    1991-01-01

    Isonicotinic acid hydrazide (isoniazid; INH) inhibition of mycolic acid synthesis was studied by using cell extracts from both INH-sensitive and -resistant strains of Mycobacterium aurum. The cell extract of the INH-sensitive strain was inhibited by INH, while the preparation from the INH-resistant strain was not. This showed that the INH resistance of mycolic acid synthesis was not due to a difference in drug uptake or the level of peroxidase activity (similar in both extracts). As INH did n...

  7. Volatile fatty acids (VFAs) production from swine manure through short-term dry anaerobic digestion and its separation from nitrogen and phosphorus resources in the digestate.

    Science.gov (United States)

    Huang, Weiwei; Huang, Wenli; Yuan, Tian; Zhao, Ziwen; Cai, Wei; Zhang, Zhenya; Lei, Zhongfang; Feng, Chuanping

    2016-03-01

    The sustainability of an agricultural system depends highly upon the recycling of all useful substances from agricultural wastes. This study explored the feasibility of comprehensive utilization of C, N and P resources in swine manure (SM) through short-term dry anaerobic digestion (AD) followed by dry ammonia stripping, aiming at achieving (1) effective total volatile fatty acids (VFAs) production and separation; (2) ammonia recovery from the digestate; and (3) preservation of high P bioavailability in the solid residue for further applications. Specifically, two ammonia stripping strategies were applied and compared in this work: (I) ammonia stripping was directly performed with the digestate from dry AD of SM (i.e. dry ammonia stripping); and (II) wet ammonia stripping was conducted by using the resultant filtrate from solid-liquid separation of the mixture of digestate and added water. Results showed that dry AD of the tested SM at 55 °C, 20% TS and unadjusted initial pH (8.6) for 8 days produced relatively high concentrations of total VFAs (94.4 mg-COD/g-VS) and ammonia-N (20.0 mg/g-VS) with high potentially bioavailable P (10.6 mg/g-TS) remained in the digestate, which was considered optimal in this study. In addition, high ammonia removal efficiencies of 96.2% and 99.7% were achieved through 3 h' dry and wet stripping (at 55 °C and initial pH 11.0), respectively, while the total VFAs concentration in the digestate/filtrate remained favorably unchanged. All experimental data from the two stripping processes well fitted to the pseudo first-order kinetic model (R(2) = 0.9916-0.9997) with comparable theoretical maximum ammonia removal efficiencies (Aeq, >90%) being obtained under the tested dry and wet stripping conditions, implying that the former was more advantageous due to its much higher volumetric total ammonia-N removal rate thus much smaller reactor volume, less energy/chemicals consumption and no foaming problems. After 8 days' dry AD and 3

  8. Microbial community adaptation influences long-chain fatty acid conversion during anaerobic codigestion of fats, oils, and grease with municipal sludge.

    Science.gov (United States)

    Ziels, Ryan M; Karlsson, Anna; Beck, David A C; Ejlertsson, Jörgen; Yekta, Sepehr Shakeri; Bjorn, Annika; Stensel, H David; Svensson, Bo H

    2016-10-15

    Codigesting fats, oils, and greases with municipal wastewater sludge can greatly improve biomethane recovery at wastewater treatment facilities. Process loading rates of fats, oils, and greases have been previously tested with little knowledge of the digester microbial community structure, and high transient fat loadings have led to long chain fatty acid (LCFA) accumulation and digester upsets. This study utilized recently-developed quantitative PCR assays for syntrophic LCFA-degrading bacteria along with 16S amplicon sequencing to relate changes in microbial community structure to LCFA accumulation during transient loading increases to an anaerobic codigester receiving waste restaurant oil and municipal wastewater sludge. The 16S rRNA gene concentration of the syntrophic β-oxidizing genus Syntrophomonas increased to ∼15% of the Bacteria community in the codigester, but stayed below 3% in the control digester that was fed only wastewater sludge. Methanosaeta and Methanospirillum were the dominant methanogenic genera enriched in the codigester, and together comprised over 80% of the Archaea community by the end of the experimental period. Constrained ordination showed that changes in the codigester Bacteria and Archaea community structures were related to measures of digester performance. Notably, the effluent LCFA concentration in the codigester was positively correlated to the specific loading rate of waste oil normalized to the Syntrophomonas 16S rRNA concentration. Specific loading rates of 0-1.5 × 10(-12) g VS oil/16S gene copies-day resulted in LCFA concentrations below 30 mg/g TS, whereas LCFA accumulated up to 104 mg/g TS at higher transient loading rates. Based on the community-dependent loading limitations found, enhanced biomethane production from high loadings of fats, oils and greases can be achieved by promoting a higher biomass of slow-growing syntrophic consortia, such as with longer digester solids retention times. This work also

  9. Salicylic acid and gentisic acid induce RNA silencing-related genes and plant resistance to RNA pathogens.

    Science.gov (United States)

    Campos, Laura; Granell, Pablo; Tárraga, Susana; López-Gresa, Pilar; Conejero, Vicente; Bellés, José María; Rodrigo, Ismael; Lisón, Purificación

    2014-04-01

    We have observed that treatments with salicylic acid (SA) or gentisic acid (GA) induced resistance to RNA pathogens such as ToMV and CEVd in tomato and Gynura auriantiaca, respectively. Accumulation of SA and GA has been found to occur in plants infected by these pathogens, thus pointing out a possible defence role of both molecules. To study the molecular basis of the observed induced resistance to RNA pathogens the induction of silencing-related genes by SA and GA was considered. For that purpose, we searched for tomato genes which were orthologous to those described in Arabidopsis thaliana, such as AtDCL1, AtDCL2, AtDCL4, AtRDR1, AtRDR2 and AtRDR6, and we tracked their induction in tomato along virus and viroid infections. We observed that CEVd significantly induced all these genes in tomato, with the exception of ToRDR6, being the induction of ToDCL4 the most outstanding. Regarding the ToMV asymptomatic infection, with the exception of ToRDR2, we observed a significant induction of all the indicated silencing-related genes, being ToDCL2 the most induced gene. Subsequently, we analyzed their transcriptional activation by SA and at the time when ToMV was inoculated on plants. ToDCL2, ToRDR1 and ToRDR2 were significantly induced by both SA and GA, whereas ToDCL1 was only induced by SA. Such an induction resulted more effective by SA treatment, which is in agreement with the stronger SA-induced resistance observed. Our results suggest that the observed delay in the RNA pathogen accumulation could be due to the pre-induction of RNA silencing-related genes by SA or GA.

  10. Complete Genome Sequences of Escherichia coli O157:H7 Strains SRCC 1675 and 28RC, Which Vary in Acid Resistance

    Science.gov (United States)

    Baranzoni, Gian Marco; Reichenberger, Erin R.; Kim, Gwang-Hee; Breidt, Frederick; Kay, Kathryn; Oh, Deog-Hwan

    2016-01-01

    The level of acid resistance among Escherichia coli O157:H7 strains varies, and strains with higher resistance to acid may have a lower infectious dose. The complete genome sequences belonging to two strains of Escherichia coli O157:H7 with different levels of acid resistance are presented here. PMID:27469964

  11. Complete genome sequences of Escherichia coli O157:H7 strains SRCC 1675 and 28RC that vary in acid resistance

    Science.gov (United States)

    The level of acid resistance among Escherichia coli O157:H7 strains varies, and strains with higher resistance to acid may have a lower infectious dose. The complete genome sequences belonging to two strains of Escherichia coli O157:H7 with different levels of acid resistance are presented....

  12. Glutamate decarboxylase-dependent acid resistance in Brucella spp.: distribution and contribution to fitness under extremely acidic conditions.

    Science.gov (United States)

    Damiano, Maria Alessandra; Bastianelli, Daniela; Al Dahouk, Sascha; Köhler, Stephan; Cloeckaert, Axel; De Biase, Daniela; Occhialini, Alessandra

    2015-01-01

    Brucella is an expanding genus of major zoonotic pathogens, including at least 10 genetically very close species occupying a wide range of niches from soil to wildlife, livestock, and humans. Recently, we have shown that in the new species Brucella microti, the glutamate decarboxylase (Gad)-dependent system (GAD system) contributes to survival at a pH of 2.5 and also to infection in mice by the oral route. In order to study the functionality of the GAD system in the genus Brucella, 47 isolates, representative of all known species and strains of this genus, and 16 strains of the closest neighbor genus, Ochrobactrum, were studied using microbiological, biochemical, and genetic approaches. In agreement with the genome sequences, the GAD system of classical species was not functional, unlike that of most strains of Brucella ceti, Brucella pinnipedialis, and newly described species (B. microti, Brucella inopinata BO1, B. inopinata-like BO2, and Brucella sp. isolated from bullfrogs). In the presence of glutamate, these species were more acid resistant in vitro than classical terrestrial brucellae. Expression in trans of the gad locus from representative Brucella species in the Escherichia coli MG1655 mutant strain lacking the GAD system restored the acid-resistant phenotype. The highly conserved GAD system of the newly described or atypical Brucella species may play an important role in their adaptation to acidic external and host environments. Furthermore, the GAD phenotype was shown to be a useful diagnostic tool to distinguish these latter Brucella strains from Ochrobactrum and from classical terrestrial pathogenic Brucella species, which are GAD negative.

  13. Emerging nalidixic acid and ciprofloxacin resistance in non-typhoidal Salmonella isolated from patients having acute diarrhoeal disease

    International Nuclear Information System (INIS)

    Non-typhoidal Salmonella are one of the key etiological agents of diarrhoeal disease. The appearence of multiple drung resistance along with resistance to quinolones in this bacterium poses a serious therapeutic problem. We determined the prevalence of nalidixic acid and ciprofloxacin resistance in non-typhodial Salmonella isolated from faecal samples of patients with acute diarroheal disease attending the outpatient and inpatient department of a hospital in Saudi Arabia during the years 1999 to 2002. Non-typhodial Salmonella were isolated from faecal samples. Antimicrobial susceptibility was tested by the disc diffusion test. MICs to nalidixic acid and ciprofloxacinwere determined by the agar dilution method. During the study period , 524 strains of non-typhoidal Salmonella were isolated. Strains belonging to serogroup C1were the commonest (41.4%) followed by serogroups B and D (15.6% and 14.5%, respectively). Resistance to ampicillin was observed in 22.9% and to trimethoprim/sulphamethoxazole in 18.5%of the strains. Nalidixic acid resistance was encounterd in 9.9% and ciprofloxacin esistance in 2.3% of the strains. Resistance to nalidixic acid significantly increased from 0.1% in 1999 to 5.51% in 2002 ( p=0.0007)and ciprofloxacin resistance increased significantly from 0.1% in 1999 to 0.9% in 2002( p=0.0001). MICs to nalidixic acid and ciprofloxacin were determined among 29 nalidixic acid-resistant strains of non-typhoidal salmonella isolated during 2002. The MIC was >256 ug /ml to nalidixic acid and 8 to 16 ug/ml to ciprofloxacin. The increasing rate of antimicrobial resistance encountered among non-tyophoidal Salmonella necessiate the judicious use of these drugs in humans. Moreover, these findings support the concern that the use of quinolones in animal feed may lead to an increasein resistance and should should be restricted. (author)

  14. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher

    2001-07-31

    During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

  15. Valproic Acid Downregulates the Expression of MGMT and Sensitizes Temozolomide-Resistant Glioma Cells

    Directory of Open Access Journals (Sweden)

    Chung Heon Ryu

    2012-01-01

    Full Text Available Temozolomide (TMZ has become a key therapeutic agent in patients with malignant gliomas; however, its survival benefit remains unsatisfactory. Valproic acid (VPA has emerged as an anticancer drug via inhibition of histone deacetylases (HDACs, but the therapeutic advantages of a combination with VPA and TMZ remain poorly understood. The main aim of the present study was to determine whether an antitumor effect could be potentiated by a combination of VPA and TMZ, especially in TMZ-resistant cell lines. A combination of VPA and TMZ had a significantly enhanced antitumor effect in TMZ-resistant malignant glioma cells (T98 and U138. This enhanced antitumor effect correlated with VPA-mediated reduced O6-methylguanine-DNA methyltransferase (MGMT expression, which plays an important role in cellular resistance to alkylating agents. In vitro, the combination of these drugs enhanced the apoptotic and autophagic cell death, as well as suppressed the migratory activities in TMZ-resistant cell lines. Furthermore, in vivo efficacy experiment showed that treatment of combination of VPA and TMZ significantly inhibited tumor growth compared with the monotherapy groups of mice. These results suggest that the clinical efficacy of TMZ chemotherapy in TMZ-resistant malignant glioma may be improved by combination with VPA.

  16. An amino acid substitution (L925V associated with resistance to pyrethroids in Varroa destructor.

    Directory of Open Access Journals (Sweden)

    Joel González-Cabrera

    Full Text Available The Varroa mite, Varroa destructor, is an important pest of honeybees and has played a prominent role in the decline in bee colony numbers over recent years. Although pyrethroids such as tau-fluvalinate and flumethrin can be highly effective in removing the mites from hives, their intensive use has led to many reports of resistance. To investigate the mechanism of resistance in UK Varroa samples, the transmembrane domain regions of the V. destructor voltage-gated sodium channel (the main target site for pyrethroids were PCR amplified and sequenced from pyrethroid treated/untreated mites collected at several locations in Central/Southern England. A novel amino acid substitution, L925V, was identified that maps to a known hot spot for resistance within the domain IIS5 helix of the channel protein; a region that has also been proposed to form part of the pyrethroid binding site. Using a high throughput diagnostic assay capable of detecting the mutation in individual mites, the L925V substitution was found to correlate well with resistance, being present in all mites that had survived tau-fluvalinate treatment but in only 8 % of control, untreated samples. The potential for using this assay to detect and manage resistance in Varroa-infected hives is discussed.

  17. An amino acid substitution (L925V) associated with resistance to pyrethroids in Varroa destructor.

    Science.gov (United States)

    González-Cabrera, Joel; Davies, T G Emyr; Field, Linda M; Kennedy, Peter J; Williamson, Martin S

    2013-01-01

    The Varroa mite, Varroa destructor, is an important pest of honeybees and has played a prominent role in the decline in bee colony numbers over recent years. Although pyrethroids such as tau-fluvalinate and flumethrin can be highly effective in removing the mites from hives, their intensive use has led to many reports of resistance. To investigate the mechanism of resistance in UK Varroa samples, the transmembrane domain regions of the V. destructor voltage-gated sodium channel (the main target site for pyrethroids) were PCR amplified and sequenced from pyrethroid treated/untreated mites collected at several locations in Central/Southern England. A novel amino acid substitution, L925V, was identified that maps to a known hot spot for resistance within the domain IIS5 helix of the channel protein; a region that has also been proposed to form part of the pyrethroid binding site. Using a high throughput diagnostic assay capable of detecting the mutation in individual mites, the L925V substitution was found to correlate well with resistance, being present in all mites that had survived tau-fluvalinate treatment but in only 8 % of control, untreated samples. The potential for using this assay to detect and manage resistance in Varroa-infected hives is discussed.

  18. Antibiotic resistance in lactic acid bacteria isolated from some pharmaceutical and dairy products

    Directory of Open Access Journals (Sweden)

    Gamal Fadl M. Gad

    2014-01-01

    Full Text Available A total of 244 lactic acid bacteria (LAB strains were isolated from 180 dairy and pharmaceutical products that were collected from different areas in Minia governorate, Egypt. LAB were identified phenotypically on basis of morphological, physiological and biochemical characteristics. Lactobacillus isolates were further confirmed using PCR-based assay. By combination of phenotypic with molecular identification Lactobacillus spp. were found to be the dominant genus (138, 76.7% followed by Streptococcus spp. (65, 36.1% and Lactococcus spp. (27, 15%. Some contaminant organisms such as (Staphylococcus spp., Escherichia coli, Salmonella spp., mould and yeast were isolated from the collected dairy samples but pharmaceutical products were free of such contaminants. Susceptibility of LAB isolates to antibiotics representing all major classes was tested by agar dilution method. Generally, LAB were highly susceptible to Beta-lactams except penicillin. Lactobacilli were resistant to vancomycin, however lactococci and streptococci proved to be very susceptible. Most strains were susceptible to tetracycline and showed a wide range of streptomycin MICs. The MICs of erythromycin and clindamycin for most of the LAB were within the normal range of susceptibility. Sixteen Lactobacillus,8 Lactococcus and 8 Streptococcus isolates including all tetracycline and/or erythromycin resistant strains were tested for the presence of tetracycline and/or erythromycin resistant genes [tet(M and/or erm(B]. PCR assays shows that some resistant strains harbor tet(M and/or erm(B resistance genes.

  19. Jasmonic acid induced resistance in grapevines to a root and leaf feeder.

    Science.gov (United States)

    Omer, A D; Thaler, J S; Granett, J; Karban, R

    2000-06-01

    We investigated the effects of induced resistance to the folivore Pacific spider mite, Tetranychus pacificus McGregor (Acari: Tetranychidae), as well as the root-feeding grape phylloxera Daktulosphaira vitifoliae (Fitch) (Homoptera: Phylloxeridae) in grapevines using exogenous applications of the natural plant inducer, jasmonic acid. Foliar jasmonic acid application at concentrations that caused no phytotoxicity significantly reduced the performance of both herbivores. There were less than half as many eggs produced by spider mites feeding on the induced leaves compared with control grapevine leaves. Induction reduced the numbers of phylloxera eggs and nymphal instars by approximately threefold and twofold, respectively, on induced compared with control grapevine roots. The negative demographic effects of jasmonic acid application appeared to be caused by changes in fecundity for the Pacific spider mite, and possibly changes in development rate and fecundity for grape phylloxera. PMID:10902339

  20. Effect of Mineral Admixtures on Resistance to Sulfuric Acid Solution of Mortars with Quaternary Binders

    Science.gov (United States)

    Makhloufi, Zoubir; Bederina, Madani; Bouhicha, Mohamed; Kadri, El-Hadj

    This research consists to study the synergistic action of three mineral additions simultaneously added to the cement. This synergistic effect has a positive effect on the sustainability of limestone mortars. Tests were performed on mortars based on crushed limestone sand and manufactured by five quaternary binders (ordinary Portland cement and CPO mixed simultaneously with filler limestone, blast-furnace and natural pozzolan). The purpose of this research was to identify the resistance of five different mortars to the solution of sulfuric acid. Changes in weight loss and compressive strength measured at 30, 60, 90, 120 and 180 days for each acid solution were studied. We followed up on the change in pH of the sulfuric acid solution at the end of each month up to 180 days.

  1. Influence of inorganic acid pickling on the corrosion resistance of magnesium alloy AZ31 sheet

    DEFF Research Database (Denmark)

    Nwaogu, Ugochukwu Chibuzoh; Blawert, C.; Scharnagl, N.;

    2009-01-01

    of micro-galvanic couples and can therefore increase corrosion attack on these alloys. Due to this influence they should be removed to obtain good corrosion resistance. In this study, the effect of inorganic acid pickling on the corrosion behaviour of a commercial AZ31 magnesium alloy sheet...... was investigated. Sulphuric, nitric and phosphoric acids of different concentrations were used to clean the alloy for various pickling times. The surface morphology, composition and phases were elucidated using scanning electron microscopy, X-ray fluorescence analysis, spark discharge-optical emission spectroscopy......, energy dispersive X-ray spectroscopy and infrared spectroscopy. The effect of surface cleaning on the corrosion properties was studied using salt spray test and electrochemical impedance spectroscopy. The experimental results show that acid pickling reduces the surface impurities and therefore enhances...

  2. Effect of the fatty acid composition of acclimated oenological Lactobacillus plantarum on the resistance to ethanol.

    Science.gov (United States)

    Bravo-Ferrada, B M; Gómez-Zavaglia, A; Semorile, L; Tymczyszyn, E E

    2015-02-01

    The aim of this work was to evaluate the changes due to acclimation to ethanol on the fatty acid composition of three oenological Lactobacillus plantarum strains and their effect on the resistance to ethanol and malic acid consumption (MAC). Lactobacillus plantarum UNQLp 133, UNQLp 65.3 and UNQLp 155 were acclimated in the presence of 6 or 10% v/v ethanol, for 48 h at 28°C. Lipids were extracted to obtain fatty acid methyl esters and analysed by gas chromatography interfaced with mass spectroscopy. The influence of change in fatty acid composition on the viability and MAC in synthetic wine was analysed by determining the Pearson correlation coefficient. Acclimated strains showed a significant change in the fatty composition with regard to the nonacclimated strains. Adaptation to ethanol led to a decrease in the unsaturated/saturated ratio, mainly resulting from an increase in the contribution of short-length fatty acid C12:0 and a decrease of C18:1. The content of C12:0 was related to a higher viability after inoculation of synthetic wine. The MAC increased at higher contents in saturated fatty acid, but its efficiency was strain dependent.

  3. Rapid Molecular Detection of Multidrug-Resistant Tuberculosis by PCR-Nucleic Acid Lateral Flow Immunoassay.

    Directory of Open Access Journals (Sweden)

    Hatairat Kamphee

    Full Text Available Several existing molecular tests for multidrug-resistant tuberculosis (MDR-TB are limited by complexity and cost, hindering their widespread application. The objective of this proof of concept study was to develop a simple Nucleic Acid Lateral Flow (NALF immunoassay as a potential diagnostic alternative, to complement conventional PCR, for the rapid molecular detection of MDR-TB. The NALF device was designed using antibodies for the indirect detection of labeled PCR amplification products. Multiplex PCR was optimized to permit the simultaneous detection of the drug resistant determining mutations in the 81-bp hot spot region of the rpoB gene (rifampicin resistance, while semi-nested PCR was optimized for the S315T mutation detection in the katG gene (isoniazid resistance. The amplification process additionally targeted a conserved region of the genes as Mycobacterium tuberculosis (Mtb DNA control. The optimized conditions were validated with the H37Rv wild-type (WT Mtb isolate and Mtb isolates with known mutations (MT within the rpoB and katG genes. Results indicate the correct identification of WT (drug susceptible and MT (drug resistant Mtb isolates, with the least limit of detection (LOD being 104 genomic copies per PCR reaction. NALF is a simple, rapid and low-cost device suitable for low resource settings where conventional PCR is already employed on a regular basis. Moreover, the use of antibody-based NALF to target primer-labels, without the requirement for DNA hybridization, renders the device generic, which could easily be adapted for the molecular diagnosis of other infectious and non-infectious diseases requiring nucleic acid detection.

  4. Resistance Training in Type 2 Diabetic Patients Improves Uric Acid Levels

    Directory of Open Access Journals (Sweden)

    R. Sousa Moisés S.S.

    2014-12-01

    Full Text Available Resistance training (RT can provide several benefits for individuals with Type 2 diabetes. The aim of this study was to investigate the effects of resistance training on the strength levels and uric acid (UA concentration in individuals with Type 2 diabetes. The study included 68 patients (57.7±9.0 years that participated in an organized program of RT for 12 weeks. The volunteers were divided into two groups: an experimental group (EG; n=34 that performed the resistance training program consisting of seven exercises executed in an alternating order based on segments; and a control group (CG; n=34 that maintained their normal daily life activities. Muscle strength and uric acid were measured both pre- and post-experiment. The results showed a significant increase in strength of the subjects in the EG for all exercises included in the study (p<0.001. Comparing the strength levels of the post-test, intergroup differences were found in supine sitting (p<0.001, leg extension (p<0.001, shoulder press (p<0.001, leg curl (p=0.001, seated row (p<0.001, leg press (p=0.001 and high pulley (p<0.001. The measured uric acid was significantly increased in both experimental and control groups (p<0.001 and p=0.001, respectively. The intergroup comparison showed a significant increase for the EG (p=0.024. We conclude that the training program was effective for strength gains despite an increase in uric acid in Type 2 diabetics.

  5. A new class of IMP dehydrogenase with a role in self-resistance of mycophenolic acid producing fungi

    DEFF Research Database (Denmark)

    Hansen, Bjarne Gram; Genee, Hans Jasper; Kaas, Christian Schrøder;

    2011-01-01

    BACKGROUND: Many secondary metabolites produced by filamentous fungi have potent biological activities, to which the producer organism must be resistant. An example of pharmaceutical interest is mycophenolic acid (MPA), an immunosuppressant molecule produced by several Penicillium species. The ta...

  6. Contribution of mdr1b-type P-glycoprotein to okadaic acid resistance in rat pituitary GH3 cells.

    Science.gov (United States)

    Ritz, V; Marwitz, J; Sieder, S; Ziemann, C; Hirsch-Ernst, K I; Quentin, I; Steinfelder, H J

    1999-08-01

    Okadaic acid as well as other, structurally different, inhibitors of serine/threonine phosphatases 1 and 2A induce apoptosis in pituitary GH3 cells. Incubation with stepwise raised concentrations of okadaic acid resulted in the isolation of cells that were increasingly less sensitive to the cytotoxic effect of this agent. After about 18 months cells were selected that survived at 300 nM okadaic acid, which is about 30 times the initially lethal concentration. This study revealed that a major pharmacokinetic mechanism underlying cell survival was the development of a P-glycoprotein-mediated multidrug resistance (MDR) phenotype. The increase in mRNA levels of the mdr1b P-glycoprotein isoform correlated with the extent of drug resistance. Functional assays revealed that increasing drug resistance was paralleled by a decreased accumulation of rhodamine 123, a fluorescent dye which is a substrate of mdr1-mediated efflux activity. Resistance could be abolished by structurally different chemosensitizers of P-glycoprotein function like verapamil and reserpine but not by the leukotriene receptor antagonist MK571 which is a modulator of the multidrug resistance-associated protein (MRP). Okadaic acid resistance included cross-resistance to other cytotoxic agents that are substrates of mdr1-type P-glycoproteins, like doxorubicin and actinomycin D, but not to non-substrates of mdr1, e.g. cytosine arabinoside. Thus, functional as well as biochemical features support the conclusion that okadaic acid is a substrate of the mdr1-mediated efflux activity in rat pituitary GH3 cells. Maintenance of resistance after withdrawal of okadaic acid as well as metaphase spreads of 100 nM okadaic acid-resistant cells suggested a stable MDR genotype without indications for the occurrence of extrachromosomal amplifications, e.g. double minute chromosomes.

  7. Gastric-resistant isoniazid pellets reduced degradation of rifampicin in acidic medium

    Directory of Open Access Journals (Sweden)

    Fátima Duarte Freire

    2014-12-01

    Full Text Available Isoniazid and rifampicin are considered the first-line medication for preventing and treating tuberculosis. Rifampicin is degraded in the stomach acidic environment, especially when combined with isoniazid, factor contributing to treatment failure. In this study, gastric-resistant isoniazid pellets were obtained to physical contact of this drug with rifampicin and to bypass the stomach´s acidic environment. The pellets were fabricated using the extrusion-spheronization technique. The coating process was conducted in a fluid spray coater using Acrycoat L 100(r solution as the coating agent. The pellets obtained were submitted to a dissolution test in HCl 0.1 N and phosphate buffer media. The results indicated that optimum gastric-resistance was only attained with the highest amount of coating material, with isoniazid almost fully released in phosphate buffer. The amount of rifampicin released from its mixture with non-coated isoniazid pellets in HCl 0.1 N was less than that released from its mixture with the enteric-coated pellets. Acrycoat L 100(r was shown to be an effective enteric/gastric-resistant coating since the stability of rifampicin appeared to be enhanced when physical contact of this drug with isoniazid was prevented at low pH.

  8. Promoter strength of folic acid synthesis genes affects sulfa drug resistance in Saccharomyces cerevisiae.

    Science.gov (United States)

    Iliades, Peter; Berglez, Janette; Meshnick, Steven; Macreadie, Ian

    2003-01-01

    The enzyme dihydropteroate synthase (DHPS) is an important target for sulfa drugs in both prokaryotic and eukaryotic microbes. However, the understanding of DHPS function and the action of antifolates in eukaryotes has been limited due to technical difficulties and the complexity of DHPS being a part of a bifunctional or trifunctional protein that comprises the upstream enzymes involved in folic acid synthesis (FAS). Here, yeast strains have been constructed to study the effects of FOL1 expression on growth and sulfa drug resistance. A DHPS knockout yeast strain was complemented by yeast vectors expressing the FOL1 gene under the control of promoters of different strengths. An inverse relationship was observed between the growth rate of the strains and FOL1 expression levels. The use of stronger promoters to drive FOL1 expression led to increased sulfamethoxazole resistance when para-aminobenzoic acid (pABA) levels were elevated. However, high FOL1 expression levels resulted in increased susceptibility to sulfamethoxazole in pABA free media. These data suggest that up-regulation of FOL1 expression can lead to sulfa drug resistance in Saccharomyces cerevisiae.

  9. Optimal level of Purple Acid Phosphatase5 is required for maintaining complete resistance to Pseudomonas syringae

    Directory of Open Access Journals (Sweden)

    Sridhar eRavichandran

    2015-08-01

    Full Text Available Plants possess an exceedingly complex innate immune system to defend against most pathogens. However, a relative proportion of the pathogens overcome host’s innate immunity and impair plant growth and productivity. We previously showed that mutation in purple acid phosphatase (PAP5 lead to enhanced susceptibility of Arabidopsis to the bacterial pathogen Pseudomonas syringae pv tomato DC3000 (Pst DC3000. Here, we report that an optimal level of PAP5 is crucial for mounting complete basal resistance. Overexpression of PAP5 impaired ICS1, PR1 expression and salicylic acid (SA accumulation similar to pap5 knockout mutant plants. Moreover, plant overexpressing PAP5 was impaired in H2O2 accumulation in response to Pst DC3000. PAP5 is localized in to peroxisomes, a known site of generation of reactive oxygen species for activation of defense responses. Taken together, our results demonstrate that optimal levels of PAP5 is required for mounting resistance against Pst DC3000 as both knockout and overexpression of PAP5 lead to compromised basal resistance.

  10. Modeling spray/puddle dissolution processes for deep-ultraviolet acid-hardened resists

    Science.gov (United States)

    Hutchinson, John M.; Das, Siddhartha; Qian, Qi-De; Gaw, Henry T.

    1993-10-01

    A study of the dissolution behavior of acid-hardened resists (AHR) was undertaken for spray and spray/puddle development processes. The Site Services DSM-100 end-point detection system is used to measure both spray and puddle dissolution data for a commercially available deep-ultraviolet AHR resist, Shipley SNR-248. The DSM allows in situ measurement of dissolution rate on the wafer chuck and hence allows parameter extraction for modeling spray and puddle processes. The dissolution data for spray and puddle processes was collected across a range of exposure dose and postexposure bake temperature. The development recipe was varied to decouple the contribution of the spray and puddle modes to the overall dissolution characteristics. The mechanisms involved in spray versus puddle dissolution and the impact of spray versus puddle dissolution on process performance metrics has been investigated. We used the effective-dose-modeling approach and the measurement capability of the DSM-100 and developed a lumped parameter model for acid-hardened resists that incorporates the effects of exposure, postexposure bake temperature and time, and development condition. The PARMEX photoresist-modeling program is used to determine parameters for the spray and for the puddle process. The lumped parameter AHR model developed showed good agreement with experimental data.

  11. Systemic resistance in Arabidopsis induced by biocontrol bacteria is independent of salicylic acid accumulation and pathogenesis-related gene expression

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Wees, A.C.M. van; Hoffland, E.; Pelt, J.A. van; Loon, L.C. van

    1996-01-01

    Systemic acquired resistance is a pathogen-inducible defense mechanism in plants. The resistant state is dependent on endogenous accumulation of salicylic acid (SA) and is characterized by the activation of genes encoding pathogenesis-related (PR) proteins. Recently, selected nonpathogenic, root-col

  12. Nucleotide precursors prevent folic acid-resistant neural tube defects in the mouse.

    Science.gov (United States)

    Leung, Kit-Yi; De Castro, Sandra C P; Savery, Dawn; Copp, Andrew J; Greene, Nicholas D E

    2013-09-01

    Closure of the neural tube during embryogenesis is a crucial step in development of the central nervous system. Failure of this process results in neural tube defects, including spina bifida and anencephaly, which are among the most common birth defects worldwide. Maternal use of folic acid supplements reduces risk of neural tube defects but a proportion of cases are not preventable. Folic acid is thought to act through folate one-carbon metabolism, which transfers one-carbon units for methylation reactions and nucleotide biosynthesis. Hence suboptimal performance of the intervening reactions could limit the efficacy of folic acid. We hypothesized that direct supplementation with nucleotides, downstream of folate metabolism, has the potential to support neural tube closure. Therefore, in a mouse model that exhibits folic acid-resistant neural tube defects, we tested the effect of specific combinations of pyrimidine and purine nucleotide precursors and observed a significant protective effect. Labelling in whole embryo culture showed that nucleotides are taken up by the neurulating embryo and incorporated into genomic DNA. Furthermore, the mitotic index was elevated in neural folds and hindgut of treated embryos, consistent with a proposed mechanism of neural tube defect prevention through stimulation of cellular proliferation. These findings may provide an impetus for future investigations of supplemental nucleotides as a means to prevent a greater proportion of human neural tube defects than can be achieved by folic acid alone.

  13. Retinoic acid therapy resistance progresses from unilineage to bilineage in HL-60 leukemic blasts.

    Directory of Open Access Journals (Sweden)

    Holly A Jensen

    Full Text Available Emergent resistance can be progressive and driven by global signaling aberrations. All-trans retinoic acid (RA is the standard therapeutic agent for acute promyelocytic leukemia, but 10-20% of patients are not responsive, and initially responsive patients relapse and develop retinoic acid resistance. The patient-derived, lineage-bipotent acute myeloblastic leukemia (FAB M2 HL-60 cell line is a potent tool for characterizing differentiation-induction therapy responsiveness and resistance in t(15;17-negative cells. Wild-type (WT HL-60 cells undergo RA-induced granulocytic differentiation, or monocytic differentiation in response to 1,25-dihydroxyvitamin D3 (D3. Two sequentially emergent RA-resistant HL-60 cell lines, R38+ and R38-, distinguishable by RA-inducible CD38 expression, do not arrest in G1/G0 and fail to upregulate CD11b and the myeloid-associated signaling factors Vav1, c-Cbl, Lyn, Fgr, and c-Raf after RA treatment. Here, we show that the R38+ and R38- HL-60 cell lines display a progressive reduced response to D3-induced differentiation therapy. Exploiting the biphasic dynamic of induced HL-60 differentiation, we examined if resistance-related defects occurred during the first 24 h (the early or "precommitment" phase or subsequently (the late or "lineage-commitment" phase. HL-60 were treated with RA or D3 for 24 h, washed and retreated with either the same, different, or no differentiation agent. Using flow cytometry, D3 was able to induce CD38, CD11b and CD14 expression, and G1/G0 arrest when present during the lineage-commitment stage in R38+ cells, and to a lesser degree in R38- cells. Clustering analysis of cytometry and quantified Western blot data indicated that WT, R38+ and R38- HL-60 cells exhibited decreasing correlation between phenotypic markers and signaling factor expression. Thus differentiation induction therapy resistance can develop in stages, with initial partial RA resistance and moderate vitamin D3 responsiveness

  14. Contribution of cell walls, nonprotein thiols, and organic acids to cadmium resistance in two cabbage varieties.

    Science.gov (United States)

    Sun, Jianyun; Cui, Jin; Luo, Chunling; Gao, Lu; Chen, Yahua; Shen, Zhenguo

    2013-02-01

    To study possible cadmium (Cd) resistance mechanisms in cabbage (Brassica oleracea L.), several parameters of metal uptake, distribution, and complexation were compared between two varieties Chunfeng [CF (Cd-tolerant)] and Lvfeng [LF (Cd-sensitive)]. Results showed that CF contained significantly lower Cd concentrations in leaves and higher Cd concentrations in roots than LF. Approximately 70 to 74 % and 66 to 68 % of Cd taken up by LF and CF, respectively, was transported to shoots. More Cd was bound to the cell walls of leaves, stems, and roots in CF than in LF. The higher capacity of CF to limit Cd uptake into shoots could be explained by immobilization of Cd in root cell walls. Compared with control groups, Cd treatment also significantly increased concentrations of nonprotein thiols, phytochelatins (PCs), and citric acid in the leaves and roots of the two varieties; the increases were more pronounced in CF than in LF. Taken together, the results suggest that the greater Cd resistance in CF than in LF may be attributable to the greater capacity of CF to limit Cd uptake into shoots and complex Cd in cell walls and metal binding ligands, such as PCs and citric acid. However, the contributions of PCs and citric acid to Cd detoxification might be smaller than those in cell walls.

  15. Granule-based anaerobic biofilm enhances propionic acid degradation under high H2 partial pressure%颗粒型厌氧生物膜改善高氢分压下丙酸降解抑制研究

    Institute of Scientific and Technical Information of China (English)

    徐恒; 汪翠萍; 颜锟; 孟尧; 刘晓吉; 王凯军

    2016-01-01

    Different types of granule-based anaerobic biofilm (with and without carriers; conductive andnon-conductive carriers) were adopted to alleviate the inhibition of propionic acid degradationunder high H2 partial pressure. And their performance was monitored and compared, at the beginning and end of biofilm cultivation. Moreover, microbial SEM images and community composition were investigated to analyze mechanisms involved in propionic acid degradation. The results showed that both conductive carbon-felt based biofilm and anaerobic granules were effective at promoting propionic acid degradationunder high H2 partial pressure, with maximum rate of 2.2 and 1.2mmol/h respectively. Propionic acid seemed to be degraded mainly via direct interspecies electron transfer (DIET) between acidogenic bacteria (Thermovirga, Levilinea, Syntrophomonas) and methanogens (Methanosaeta) for carbon-felt based biofilm. Nevertheless, degradation of propionic acid by anaerobic granules was possibly attributed to syntrophic operation of acidogenic bacteria (syntrophobacter) and methanogens (Methanolinea,Methanobacterium).%为了改善氢辅助型原位沼气提纯系统中高氢分压对丙酸降解的抑制,考察了不同颗粒型厌氧生物膜(有无载体、导电和非导电载体)培养初期和末期的丙酸降解性能;并通过微生物形态和群落分析,探讨了颗粒型生物膜丙酸降解机制.结果表明,导电碳毡厌氧生物膜和厌氧颗粒污泥能有效改善高氢分压下丙酸降解抑制问题.其最大丙酸降解速率分别达到2.2,1.2mmol/(L?h).碳毡厌氧生物膜可能主要通过产酸细菌(Thermovirga、Levilinea、Syntrophomonas属)和产甲烷古菌(Methanosaeta属)的电子直接传递(DIET)途径实现丙酸的降解;而厌氧颗粒污泥降解丙酸的途径可能主要依靠产酸细菌(Syntrophobacter属)与嗜氢型甲烷菌(Methanolinea、Methanobacterium属)的共生营养代谢过程.

  16. Characterisation of a cell wall-anchored protein of Staphylococcus saprophyticus associated with linoleic acid resistance

    Directory of Open Access Journals (Sweden)

    King Nathan P

    2012-01-01

    Full Text Available Abstract Background The Gram-positive bacterium Staphylococcus saprophyticus is the second most frequent causative agent of community-acquired urinary tract infections (UTI, accounting for up to 20% of cases. A common feature of staphylococci is colonisation of the human skin. This involves survival against innate immune defenses including antibacterial unsaturated free fatty acids such as linoleic acid which act by disrupting bacterial cell membranes. Indeed, S. saprophyticus UTI is usually preceded by perineal skin colonisation. Results In this study we identified a previously undescribed 73.5 kDa cell wall-anchored protein of S. saprophyticus, encoded on plasmid pSSAP2 of strain MS1146, which we termed S. saprophyticus surface protein F (SssF. The sssF gene is highly prevalent in S. saprophyticus clinical isolates and we demonstrate that the SssF protein is expressed at the cell surface. However, unlike all other characterised cell wall-anchored proteins of S. saprophyticus, we were unable to demonstrate a role for SssF in adhesion. SssF shares moderate sequence identity to a surface protein of Staphylococcus aureus (SasF recently shown to be an important mediator of linoleic acid resistance. Using a heterologous complementation approach in a S. aureus sasF null genetic background, we demonstrate that SssF is associated with resistance to linoleic acid. We also show that S. saprophyticus strains lacking sssF are more sensitive to linoleic acid than those that possess it. Every staphylococcal genome sequenced to date encodes SssF and SasF homologues. Proteins in this family share similar predicted secondary structures consisting almost exclusively of α-helices in a probable coiled-coil formation. Conclusions Our data indicate that SssF is a newly described and highly prevalent surface-localised protein of S. saprophyticus that contributes to resistance against the antibacterial effects of linoleic acid. SssF is a member of a protein family

  17. Surface Resistance of Jute Fibre/Polylactic Acid Biocomposite to Wet Heat

    Science.gov (United States)

    Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

    2016-04-01

    Jute fibre/polylactic acid (PLA) composite is of special interest because both resin and reinforcement come from renewable resources. Thus, it could be a more eco-friendly alternative to glass fibre composite [1] and to conventional wood-based panels made with phenol-formaldehyde resin which present many drawbacks for the workers and the environment [2]. Yet the water affinity of the natural fibres, the susceptibility of PLA towards hydrolysis and the low glass transition of the PLA raise a question about the surface resistance of such composites to wet heat in service condition for a furniture application [3]. In this work, the surface resistance of PLA/jute composite alone and with two different varnishes are investigated in regard to an interior application following the standard test method in accordance to BS EN 18721:2009: "Furniture: assessment of surface resistance to wet heat". It is compared to two common wood based panels, plywood and hardboard. After test, the composite material surface is found to be more affected than plywood and hardboard, but it becomes resistant to wet heat when a layer of biosourced varnish or petrol-based polyurethane varnish are applied on the surface.

  18. Genome Sequence Analysis of the Naphthenic Acid Degrading and Metal Resistant Bacterium Cupriavidus gilardii CR3.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Wang

    Full Text Available Cupriavidus sp. are generally heavy metal tolerant bacteria with the ability to degrade a variety of aromatic hydrocarbon compounds, although the degradation pathways and substrate versatilities remain largely unknown. Here we studied the bacterium Cupriavidus gilardii strain CR3, which was isolated from a natural asphalt deposit, and which was shown to utilize naphthenic acids as a sole carbon source. Genome sequencing of C. gilardii CR3 was carried out to elucidate possible mechanisms for the naphthenic acid biodegradation. The genome of C. gilardii CR3 was composed of two circular chromosomes chr1 and chr2 of respectively 3,539,530 bp and 2,039,213 bp in size. The genome for strain CR3 encoded 4,502 putative protein-coding genes, 59 tRNA genes, and many other non-coding genes. Many genes were associated with xenobiotic biodegradation and metal resistance functions. Pathway prediction for degradation of cyclohexanecarboxylic acid, a representative naphthenic acid, suggested that naphthenic acid undergoes initial ring-cleavage, after which the ring fission products can be degraded via several plausible degradation pathways including a mechanism similar to that used for fatty acid oxidation. The final metabolic products of these pathways are unstable or volatile compounds that were not toxic to CR3. Strain CR3 was also shown to have tolerance to at least 10 heavy metals, which was mainly achieved by self-detoxification through ion efflux, metal-complexation and metal-reduction, and a powerful DNA self-repair mechanism. Our genomic analysis suggests that CR3 is well adapted to survive the harsh environment in natural asphalts containing naphthenic acids and high concentrations of heavy metals.

  19. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.;

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulated...... earlier by Vavilin and Angelidaki (2005) were used to modernize a kinetic scheme and to obtain the corresponding kinetic coefficients. In the new models, hydrolytic microorganisms were included using Contois kinetics for the hydrolysis/acidogenesis degradation of municipal solid waste (MSW). Monod...... kinetics was applied for description of methanogenesis. Both hydrolytic and methanogenic microorganisms were assumed to be inhibited by high volatile fatty acids (VFA) concentration. According to the new distributed models, the mixing level reduction expressed by increasing dimensionless Peclet number may...

  20. Characterization and performance of carbonaceous materials obtained from exhausted sludges for the anaerobic biodecolorization of the azo dye Acid Orange II

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Carbonaceous materials were prepared from exhausted sludge materials. • High surface area and good physicochemical properties were achieved. • Utilization of waste sludge materials and mixed anaerobic cultures were used in a continuous anaerobic UPBR system (upflow packed bed biological reactor). • Effective treatment of dye contaminated wastewater in a cheapest and environmental friendly method was demonstrated. - Abstract: This work presents the preliminary study of new carbonaceous materials (CMs) obtained from exhausted sludge, their use in the heterogeneous anaerobic process of biodecolorization of azo dyes and the comparison of their performance with one commercial active carbon. The preparation of carbonaceous materials was conducted through chemical activation and carbonization. Chemical activation was carried out through impregnation of sludge-exhausted materials with ZnCl2 and the activation by means of carbonization at different temperatures (400, 600 and 800 °C). Their physicochemical and surface characteristics were also investigated. Sludge based carbonaceous (SBC) materials SBC400, SBC600 and SBC800 present values of 13.0, 111.3 and 202.0 m2/g of surface area. Biodecolorization levels of 76% were achieved for SBC600 and 86% for SBC800 at space time (τ) of 1.0 min, similar to that obtained with commercial activated carbons in the continuous anaerobic up-flow packed bed reactor (UPBR). The experimental data fit well to the first order kinetic model and equilibrium data are well represented by the Langmuir isotherm model. Carbonaceous materials show high level of biodecolorization even at very short space times. Results indicate that carbonaceous materials prepared from sludge-exhausted materials have outstanding textural properties and significant degradation capacity for treating textile effluents

  1. The correlation between free fatty acid and insulin resistance in ischemic stroke patients

    Institute of Scientific and Technical Information of China (English)

    刘怀平

    2013-01-01

    Objective To explore the level of free fatty acid (FFA) in ischemic stroke (IS) patients and its correlation with insulin resistance (IR) .Methods This study was case-control study.Patients who were diagnosed with IS were followed up from June,2011 to September,2012in Tianjin Third Central Hospital.The 180 IS patients were divied into large infarct (57) ,middle infarct (63) and small infarct (60) according to the area of infarct.At the same time,60 healthy persons were selected as con-

  2. Estimation of Wear Resistance in Acid Solution of Dental Ceramics by Neural Network

    OpenAIRE

    Lisjak, D.; Čurković, L.; Živko-Babić, J.; Jakovac, M.

    2002-01-01

    It is known that exposure to acid causes damage to the glass surface. The aim of this study was to examine wear resistance, measuring the mass change of dental ceramics after contact with 10-3 mol dm-3 HCl at temperature of 50°C. Four samples of dental ceramics were analyzed: feldspatic ceramic, hydrothermal ceramic, glass ceramic for staining and glass ceramic for layering. The mass concentrations of eluted Na+, K+ and Ca2+ were determined by ion chromatography (IC) and mass concentration...

  3. Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy

    OpenAIRE

    Joy, Jordan M; Gundermann, David M.; Ryan P. Lowery; Jäger, Ralf; McCleary, Sean A; Purpura, Martin; Roberts, Michael D.; Wilson, Stephanie MC; Hornberger, Troy A.; Wilson, Jacob M.

    2014-01-01

    Introduction The lipid messenger phosphatidic acid (PA) plays a critical role in the stimulation of mTOR signaling. However, the mechanism by which PA stimulates mTOR is currently unknown. Therefore, the purpose of this study was to compare the effects of various PA precursors and phospholipids on their ability to stimulate mTOR signaling and its ability to augment resistance training-induced changes in body composition and performance. Methods In phase one, C2C12 myoblasts cells were stimula...

  4. Gender comparisons in anaerobic power and anaerobic capacity tests.

    OpenAIRE

    Maud, P. J.; Shultz, B B

    1986-01-01

    The purpose of the study was to compare anaerobic power and anaerobic capacity test scores between young active men and women. Three performance measures of anaerobic power and two of anaerobic capacity were administered to a sample comprising 52 male and 50 female college students (means age = 21.4 yrs). Results indicated significant differences between men and women in body height, weight and per cent fat, in fat free mass (FFM), anaerobic power, and anaerobic capacity when recorded as gros...

  5. Corrosion resistance of the composite materials: nanocrystalline powder – polymer type in acid environment

    Directory of Open Access Journals (Sweden)

    B. Ziębowicz

    2009-10-01

    Full Text Available Purpose: The paper presents corrosion resistance of composite materials Fe73.5Cu1Nb3Si13.5B9 – PEHD type in sulphuric acid and hydrochloric acid environments.Design/methodology/approach: Composite materials Fe73.5Cu1Nb3Si13.5B9 – PEHD type were manufactured by one-sided uniaxal pressing. The amount of polymer matrix was 2.5%, 5.0%, 7.5%, wt. Powder of the Fe73.5Cu1Nb3Si13.5B9 was made by the high-energy grinding in the shaker type 8000SPEX CertiPrep Mixer/Mill for 1 h, 3 h, 5 h. Composite materials were placed in a corrosive environment and two tests were carried out as specified below: test at the temperature of 25°C, 0.1 M solution of hydrochloric acid HCl, time 348 h; test temperature 25°C, 0.1 M solution of sulphuric acid H2SO4, time 348 h, test temperature 25°C.Findings: Obtained results of corrosion resistance allow to evaluate corrosion wear of composite materials FINEMET (Fe73.5Cu1Nb3Si13.5B9 – PEHD in acidic solutions of 0.1M HCl and 0.1M H2SO4. It was found that the composite materials with 7.5% wt. of polyethylene portion show the best corrosion resistance.Research limitations/implications: Composite materials Fe73.5Cu1Nb3Si13.5B9– PEHD type manufacturing greatly expand the application possibilities of soft magnetic materials nanocrystalline powders however further examination to obtain improved properties of magnetic composite materials and investigations of new machines and devices constructions with these materials elements are still needed.Originality/value: Results allow to complete data concerning composite materials nanocrystalline powder – polymer type which are an attractive alternative for traditional materials with specific magnetic properties. Results are the base for further investigations of the impact of corrosion environment on the magnetic properties such composite materials.

  6. Salicylic acid confers enhanced resistance to Glomerella leaf spot in apple.

    Science.gov (United States)

    Zhang, Ying; Shi, Xiangpeng; Li, Baohua; Zhang, Qingming; Liang, Wenxing; Wang, Caixia

    2016-09-01

    Glomerella leaf spot (GLS) caused by Glomerella cingulata is a newly emergent disease that results in severe defoliation and fruit spots in apple. Currently, there are no effective means to control this disease except for the traditional fungicide sprays. Induced resistance by elicitors against pathogens infection is a widely accepted eco-friendly strategy. In the present study, we investigated whether exogenous application of salicylic acid (SA) could improve resistance to GLS in a highly susceptible apple cultivar (Malus domestica Borkh. cv. 'Gala') and the underlying mechanisms. The results showed that pretreatment with SA, at 0.1-1.0 mM, induced strong resistance against GLS in 'Gala' apple leaves, with SA treated leaves showing significant reduction in lesion numbers and disease index. Concurrent with the enhanced disease resistance, SA treatment markedly increased the total antioxidant capacity (T-AOC) and defence-related enzyme activities, including catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO). As expected, SA treatment also induced the expression levels of five pathogenesis-related (PR) genes including PR1, PR5, PR8, Chitinase and β-1,3-glucanase. Furthermore, the most pronounced and/or rapid increase was observed in leaves treated with SA and subsequently inoculated with G. cingulata compared to the treatment with SA or inoculation with the pathogen. Together, these results suggest that exogenous SA triggered increase in reactive oxygen species levels and the antioxidant system might be responsible for enhanced resistance against G. cingulata in 'Gala' apple leaves. PMID:27139585

  7. Fatty acid profiles from the plasma membrane and detergent resistant membranes of two plant species.

    Science.gov (United States)

    Carmona-Salazar, Laura; El Hafidi, Mohammed; Gutiérrez-Nájera, Nora; Noyola-Martínez, Liliana; González-Solís, Ariadna; Gavilanes-Ruíz, Marina

    2015-01-01

    It is essential to establish the composition of the plant plasma membrane in order to understand its organization and behavior under continually changing environments. Knowledge of the lipid phase, in particular the fatty acid (FA) complex repertoire, is important since FAs determine many of the physical-chemical membrane properties. FAs are constituents of the membrane glycerolipid and sphingolipid backbones and can also be linked to some sterols. In addition, FAs are components of complex lipids that can constitute membrane micro-domains, and the use of detergent-resistant membranes is a common approach to study their composition. The diversity and cellular allocation of the membrane lipids containing FAs are very diverse and the approaches to analyze them provide only general information. In this work, a detailed FA analysis was performed using highly purified plasma membranes from bean leaves and germinating maize embryos and their respective detergent-resistant membrane preparations. The analyses showed the presence of a significant amount of very long chain FAs (containing 28C, 30C and 32C), in both plasma membrane preparations from bean and maize, that have not been previously reported. Herein is demonstrated that a significant enrichment of very long chain saturated FAs and saturated FAs can occur in detergent-resistant membrane preparations, as compared to the plasma membranes from both plant species. Considering that a thorough analysis of FAs is rarely performed in purified plasma membranes and detergent-resistant membranes, this work provides qualitative and quantitative evidence on the contributions of the length and saturation of FAs to the organization of the plant plasma membrane and detergent-resistant membranes.

  8. High Uric Acid Induces Insulin Resistance in Cardiomyocytes In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Li Zhi

    Full Text Available Clinical studies have shown hyperuricemia strongly associated with insulin resistance as well as cardiovascular disease. Direct evidence of how high uric acid (HUA affects insulin resistance in cardiomyocytes, but the pathological mechanism of HUA associated with cardiovascular disease remains to be clarified. We aimed to examine the effect of HUA on insulin sensitivity in cardiomyocytes and on insulin resistance in hyperuricemic mouse model. We exposed primary cardiomyocytes and a rat cardiomyocyte cell line, H9c2 cardiomyocytes, to HUA, then quantified glucose uptake with a fluorescent glucose analog, 2-NBDG, after insulin challenge and detected reactive oxygen species (ROS production. Western blot analysis was used to examine the levels of insulin receptor (IR, phosphorylated insulin receptor substrate 1 (IRS1, Ser307 and phospho-Akt (Ser473. We monitored the impact of HUA on insulin resistance, insulin signaling and IR, phospho-IRS1 (Ser307 and phospho-Akt levels in myocardial tissue of an acute hyperuricemia mouse model established by potassium oxonate treatment. HUA inhibited insulin-induced glucose uptake in H9c2 and primary cardiomyocytes. It increased ROS production; pretreatment with N-acetyl-L-cysteine (NAC, a ROS scavenger, reversed HUA-inhibited glucose uptake induced by insulin. HUA exposure directly increased the phospho-IRS1 (Ser307 response to insulin and inhibited that of phospho-Akt in H9C2 cardiomyocytes, which was blocked by NAC. Furthermore, the acute hyperuricemic mice model showed impaired glucose tolerance and insulin tolerance accompanied by increased phospho-IRS1 (Ser307 and inhibited phospho-Akt response to insulin in myocardial tissues. HUA inhibited insulin signaling and induced insulin resistance in cardiomyocytes in vitro and in vivo, which is a novel potential mechanism of hyperuricemic-related cardiovascular disease.

  9. Design, synthesis, and evaluation of caffeic acid amides as synergists to sensitize fluconazole-resistant Candida albicans to fluconazole.

    Science.gov (United States)

    Dai, Li; Zang, Chengxu; Tian, Shujuan; Liu, Wei; Tan, Shanlun; Cai, Zhan; Ni, Tingjunhong; An, Maomao; Li, Ran; Gao, Yue; Zhang, Dazhi; Jiang, Yuanying

    2015-01-01

    A series of caffeic acid amides were designed, synthesized, and their synergistic activity with fluconazole against fluconazole-resistant Candida albicans was evaluated in vitro. The title caffeic acid amides 3-30 except 26 exhibited potent activity, and the subsequent SAR study was conducted. Compound 3, 5, 21, and 34c, at a concentration of 1.0 μg/ml, decreased the MIC₈₀ of fluconazole from 128.0 μg/ml to 1.0-0.5 μg/ml against the fluconazole-resistant C. albicans. This result suggests that the caffeic acid amides, as synergists, can sensitize drug-resistant fungi to fluconazole. The SAR study indicated that the dihydroxyl groups and the amido groups linking to phenyl or heterocyclic rings are the important pharmacophores of the caffeic acid amides.

  10. Investigation of carbon storage regulation network (csr genes) and phenotypic differences between acid sensitive and resistant Escherichia coli O157:H7 strains

    Science.gov (United States)

    Background: Escherichia coli O157:H7 and related serotype strains have previously been shown to vary in acid resistance, however, little is known about strain specific mechanisms of acid resistance. We examined sensitive and resistant E. coli strains to determine the effects of growth in minimal and...

  11. Modifications in membrane fatty acid composition of Salmonella typhimurium in response to growth conditions and their effect on heat resistance.

    Science.gov (United States)

    Alvarez-Ordóñez, Avelino; Fernández, Ana; López, Mercedes; Arenas, Ricardo; Bernardo, Ana

    2008-04-30

    The effects of growth temperature (in the range 10-45 degrees C) and acidification up to pH 4.5 of the culture medium (Brain Heart Infusion, BHI) with different organic acids (acetic, citric and lactic) and hydrochloric acid on membrane fatty acid composition and heat resistance of Salmonella typhimurium CECT 443 were studied. The heat resistance was maximal in cells grown at 45 degrees C (cells grown in non-acidified BHI showed a D58-value of 0.90 min) and decreased with decreasing growth temperature up to 10 degrees C (D58-value of 0.09 min). The growth of cells in acidified media caused an increase in their heat resistance. In general, acid adapted cells showed D-values of between 1.5 and 2 times higher than the corresponding for non-acid adapted control cells. This cross-protection response, which has important implications in food processing, was not dependent on the pH value and the acid used to acidify the growth medium. A membrane adaptation corresponding to an increase in the unsaturated to saturated fatty acids ratio (UFA/SFA) and membrane fluidity was observed at low growth temperature. Moreover, the acidification of the growth medium caused a decrease in UFA/SFA ratio and in the C18:1 relative concentration, and an increase in cyclopropane fatty acids (CFA) content mainly due to the increase in cyc19 relative concentration. Thus, acid adapted cells showed CFA levels 1.5 times higher than non-acid adapted control cells. A significant proportion of unsaturated fatty acids were converted to their cyclopropane derivatives during acid adaptation. These changes in membrane fatty acid composition result in cells with decreased membrane fluidity. A clear relation between membrane fatty acid composition and heat resistance was observed. In general, D-values were maximum for cells with low UFA/SFA ratio, and, consequently, with low membrane fluidity. Moreover, CFA formation played a major role in protecting acid adapted cells from heat inactivation. However

  12. Hyaluronic acid-bound letrozole nanoparticles restore sensitivity to letrozole-resistant xenograft tumors in mice.

    Science.gov (United States)

    Nair, Hareesh B; Huffman, Steven; Veerapaneni, Poornachand; Kirma, Nameer B; Binkley, Peter; Perla, Rao P; Evans, Dean B; Tekmal, Rajeshwar R

    2011-05-01

    Letrozole is a potent aromatase inhibitor and superior to other defined selective estrogen receptor modulators such as tamoxifen in treating hormone-responsive postmenopausal breast cancer patients. Patients who receive this drug may become insensitive to the effects of estrogen deprivation induced by letrozole. Letrozole has known side effects on bone metabolism due to systemic ablation of estrogen production. The purpose of this study was to examine the therapeutic efficacy of hyaluronic acid-bound letrozole nanoparticles (HA-Letr-NPs) in restoring sensitivity to letrozole-resistant (LTLT-Ca) cells. To target letrozole to LTLT-Ca cells, hyaluronic acid-bound letrozole nanoparticles were prepared by nanoprecipitation using biodegradable PLGA-PEG co-polymer. Binding specificity of HA to CD44 on the cell surface was analyzed in vitro using FITC-CD44 Ab and CD44 siRNA by flow cytometry. Effects on in vitro cytotoxicity and aromatase enzymatic activity of HA-Letr-NPs were performed in MCF-7 breast cancer cells, MCF-7 cells over-expressing aromatase (MCF-7/Aro), and LTLT-Ca cells resistant to letrozole. Preclinical efficacy of HA-Letr-NPs was examined in mice using LTLT-Ca xenograft tumors. HA-Letr-NPs were restricted to a maximum size of 100 nm. The in vitro drug release assay showed that the highest released concentration of letrozole occurred after 23 hours at 37 degrees C in phosphate-buffered saline. HA-Letr-NPs on MCF-7/Aro and LTLT-Ca cells showed an IC50 of 2 microM and 5 microM, respectively. HA-Letr-NPs were more efficacious in inhibiting tumor growth, reducing in vitro cellular and in vivo tumor aromatase enzyme activity more than the corresponding Letr-NPs or letrozole. HA-Letr-NPs restored and maintained a prolonged sensitivity and targeted delivery of letrozole in letrozole-resistant tumors in vivo. PMID:21780370

  13. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    Science.gov (United States)

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure.

  14. Anaerobic digestion of aliphatic polyesters.

    Science.gov (United States)

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry. PMID:27191559

  15. Association between Dietary Acid Load and Insulin Resistance: Tehran Lipid and Glucose Study

    Science.gov (United States)

    Moghadam, Sajjad Khalili; Bahadoran, Zahra; Mirmiran, Parvin; Tohidi, Maryam; Azizi, Fereidoun

    2016-01-01

    In the current study, we investigated the longitudinal association between dietary acid load and the risk of insulin resistance (IR) in the Tehranian adult population. This longitudinal study was conducted on 925 participants, aged 22~80 years old, in the framework of the third (2006~2008) and fourth (2009~2011) phases of the Tehran Lipid and Glucose Study. At baseline, the dietary intake of subjects was assessed using a validated semi-quantitative food frequency questionnaire, and the potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores were calculated at baseline. Fasting serum insulin and glucose were measured at baseline and again after a 3-year of follow-up; IR was defined according to optimal cut-off values. Multiple logistic regression models were used to estimate the risk of IR according to the PRAL and NEAP quartile categories. Mean age and body mass index of the participants were 40.3 years old of 26.4 kg/m2, respectively. Mean PRAL and NEAP scores were −11.2 and 35.6 mEq/d, respectively. After adjustment for potential confounders, compared to the lowest quartile of PRAL and NEAP, the highest quartile was accompanied with increased risk of IR [odds ratio (OR)=2.81, 95% confidence interval (CI)=1.32~5.97 and OR=2.18, 95% CI=1.03 ~4.61, respectively]. Our findings suggest that higher acidic dietary acid-base load, defined by higher PRAL and NEAP scores, may be a risk factor for the development of IR and related metabolic disorders. PMID:27390726

  16. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9...

  17. Anaerobic sludge granulation

    NARCIS (Netherlands)

    Hulshoff Pol, L.W.; Castro Lopes, de S.I.; Lettinga, G.; Lens, P.N.L.

    2004-01-01

    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades
    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades. The initial stage

  18. The effects of a pre-workout supplement containing caffeine, creatine, and amino acids during three weeks of high-intensity exercise on aerobic and anaerobic performance

    OpenAIRE

    Kendall Kristina L; Fukuda David H; Smith Abbie E; Stout Jeffrey R

    2010-01-01

    Abstract Background A randomized, single-blinded, placebo-controlled, parallel design study was used to examine the effects of a pre-workout supplement combined with three weeks of high-intensity interval training (HIIT) on aerobic and anaerobic running performance, training volume, and body composition. Methods Twenty-four moderately-trained recreational athletes (mean ± SD age = 21.1 ± 1.9 yrs; stature = 172.2 ± 8.7 cm; body mass = 66.2 ± 11.8 kg, VO2max = 3.21 ± 0.85 l·min-1, percent body ...

  19. Antibacterial synergy between rosmarinic acid and antibiotics against methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Ekambaram, Sanmuga Priya; Perumal, Senthamil Selvan; Balakrishnan, Ajay; Marappan, Nathiya; Gajendran, Sabari Srinivasan; Viswanathan, Vinodhini

    2016-01-01

    Aim/Background: Medicinal plants have ability to resist microorganisms by synthesizing secondary metabolites such as phenols. Rosmarinic acid (RA) is a phenylpropanoid widely distributed in plants and well known as therapeutic and cosmetic agent. Methicillin-resistant Staphylococcus aureus (MRSA) which is resistant to all kinds of β-lactams, threatens even most potent antibiotics. To improve the efficiency of antibiotics against multi-drug resistant bacteria and to reduce the antibiotic dose, the antibacterial activity and the synergistic effect of RA with standard antibiotics against S. aureus and MRSA was investigated. Materials and Methods: Antibacterial activity of RA against S. aureus and a clinical isolate of MRSA was evaluated by agar well diffusion method. Minimum inhibitory concentration (MIC) of RA was determined by broth dilution method. Synergism of RA with various antibiotics against S. aureus and MRSA was studied by broth checkerboard method and time-kill kinetic assay. Effect of RA on microbial surface components recognizing adhesive matrix molecules (MSCRAMM’s) of S. aureus and MRSA was studied using sodium dodecyl sulfate - polyacrylamide gel electrophoresis. Results: MIC of RA was found to be 0.8 and 10 mg/ml against S. aureus and MRSA, respectively. RA was synergistic with vancomycin, ofloxacin, and amoxicillin against S. aureus and only with vancomycin against MRSA. The time-kill analysis revealed that synergistic combinations were a more effective than individual antibiotics. MSCRAMM’s protein expression of S. aureus and MRSA was markedly suppressed by RA + vancomycin combination rather than RA alone. Conclusion: The synergistic effects of RA with antibiotics were observed against S. aureus and MRSA. RA showed inhibitory effect on the surface proteins MSCRAMM’s. Even though RA was shown to exhibit a synergistic effect with antibiotics, the MIC was found to be higher. Thus, further studies on increasing the efficacy of RA can develop it

  20. Acid diffusion, standing waves, and information theory: a molecular-scale model of chemically amplified resist

    Science.gov (United States)

    Trefonas, Peter, III; Allen, Mary T.

    1992-06-01

    Shannon's information theory is adapted to analyze the photolithographic process, defining the mask pattern as the prior state. Definitions and constraints to the general theory are developed so that the information content at various stages of the lithographic process can be described. Its application is illustrated by exploring the information content within projected aerial images and resultant latent images. Next, a 3-dimensional molecular scale model of exposure, acid diffusion, and catalytic crosslinking in acid-hardened resists (AHR) is presented. In this model, initial positions of photogenerated acids are determined by probability functions generated from the aerial images and the local light intensity in the film. In order to simulate post-exposure baking processes, acids are diffused in a random walk manner, for which the catalytic chain length and the average distance between crosslinks can be set. Crosslink locations are defined in terms of the topologically minimized number required to link different chains. The size and location of polymer chains involved in a larger scale crosslinked network is established and related to polymer solubility. In this manner, the nature of the crosslinked latent image can be established. Good correlation with experimental data is found for the calculated percent insolubilization as a function of dose when the rms acid diffusion length is about 500 angstroms. Information analysis is applied in detail to the specific example of AHR chemistry. The information contained within the 3-D crosslinked latent image is explored as a function of exposure dose, catalytic chain length, average distance between crosslinks. Eopt (the exposure dose which optimizes the information contained within the latent image) was found to vary with catalytic chain length in a manner similar to that observed experimentally in a plot of E90 versus post-exposure bake time. Surprisingly, the information content of the crosslinked latent image remains

  1. Heat-resistance of Hamigera avellanea and Thermoascus crustaceus isolated from pasteurized acid products.

    Science.gov (United States)

    Scaramuzza, Nicoletta; Berni, Elettra

    2014-01-01

    Products containing sugar or fruit derivatives are usually subjected to a pasteurization process that can anyway be ineffective to kill ascospores from heat-resistant molds. Although the most occurring and economically relevant heat-resistant species belong to Byssochlamys, Neosartorya, Talaromyces, and Eupenicillium genera, an increasing number of uncommon heat-resistant isolates have been recently detected as spoiling microorganisms in such products. Since Hamigera spp. and Thermoascus spp. were those more frequently isolated at SSICA, heat resistance of Hamigera avellanea and Thermoascus crustaceus strains from pasteurized acid products was studied in apple juice, in blueberry and grape juice and in a buffered glucose solution. Data obtained from thermal death curves and statistical elaboration of raw data showed that D values of H. avellanea may vary between 11.11 and 66.67 min at 87°C, between 4.67 and 13.51 at 90°C, and between 0.43 and 1.52 min at 95°C. Similarly, D values of T. crustaceus may vary between 18.52 and 90.91 min at 90°C, between 2.79 and 19.23 at 93°C, and between 1.11 and 2.53 min at 95°C. For both strains studied, the z-values calculated from the decimal reduction time curves did not prove to be significantly influenced by the heating medium, that being 4.35°C, 5.39°C or 5.27°C for H. avellanea and 4.42°C, 3.69°C or 3.37°C for T. crustaceus, respectively in apple juice, in blueberry and grape juice or in the buffered glucose solution. Considering the pasteurization treatments industrially applied to fruit-based foods, the variation of thermal parameters does not seem to be a possible way to avoid product spoilage by these two species and only good practices applied to reduce the original load of heat-resistant fungi can help producers to prevent losses in contaminated finished products, as usually happens for other heat resistant molds.

  2. Hydroxyapatite coatings for marble protection: Optimization of calcite covering and acid resistance

    Science.gov (United States)

    Graziani, Gabriela; Sassoni, Enrico; Franzoni, Elisa; Scherer, George W.

    2016-04-01

    Hydroxyapatite (HAP) has a much lower dissolution rate and solubility than calcite, especially in an acidic environment, so it has been proposed for the protection of marble against acidic rain corrosion. Promising results were obtained, but further optimization is necessary as the treated layer is often incomplete, cracked and/or porous. In this paper, several parameters were investigated to obtain a coherent, uncracked layer, and to avoid the formation of metastable, soluble phases instead of HAP: the role of the pH of the starting solution; the effect of organic and inorganic additions, and in particular that of ethanol, as it is reported to adsorb on calcite, hence possibly favoring the growth of the HAP layer. Finally, a double application of the treatment was tested. Results were compared to those obtained with ammonium oxalate treatment, widely investigated for marble protection. Results indicate that adding small amounts of ethanol to the formulation remarkably increases the acid resistance of treated samples, and yields better coverage of the surface without crack formation. The effectiveness of the treatment is further enhanced when a second treatment is applied. The efficacy of ethanol-doped DAP mixtures was found to be remarkably higher than that of ammonium oxalate based treatments.

  3. Human Insulin Resistance Is Associated With Increased Plasma Levels of 12α-Hydroxylated Bile Acids

    Science.gov (United States)

    Haeusler, Rebecca A.; Astiarraga, Brenno; Camastra, Stefania; Accili, Domenico; Ferrannini, Ele

    2013-01-01

    Bile acids (BAs) exert pleiotropic metabolic effects, and physicochemical properties of different BAs affect their function. In rodents, insulin regulates BA composition, in part by regulating the BA 12α-hydroxylase CYP8B1. However, it is unclear whether a similar effect occurs in humans. To address this question, we examined the relationship between clamp-measured insulin sensitivity and plasma BA composition in a cohort of 200 healthy subjects and 35 type 2 diabetic (T2D) patients. In healthy subjects, insulin resistance (IR) was associated with increased 12α-hydroxylated BAs (cholic acid, deoxycholic acid, and their conjugated forms). Furthermore, ratios of 12α-hydroxylated/non–12α-hydroxylated BAs were associated with key features of IR, including higher insulin, proinsulin, glucose, glucagon, and triglyceride (TG) levels and lower HDL cholesterol. In T2D patients, BAs were nearly twofold elevated, and more hydrophobic, compared with healthy subjects, although we did not observe disproportionate increases in 12α-hydroxylated BAs. In multivariate analysis of the whole dataset, controlling for sex, age, BMI, and glucose tolerance status, higher 12α-hydroxy/non–12α-hydroxy BA ratios were associated with lower insulin sensitivity and higher plasma TGs. These findings suggest a role for 12α-hydroxylated BAs in metabolic abnormalities in the natural history of T2D and raise the possibility of developing insulin-sensitizing therapeutics based on manipulations of BA composition. PMID:23884887

  4. 提高太湖蓝藻厌氧发酵产丁酸的预处理方法%Pretreatment Methods to Enhance the Butyric Acid Production by Anaerobic Fermentation on Taihu Lake Blue-Green Algae

    Institute of Scientific and Technical Information of China (English)

    任洪艳; 吕娴; 阮文权

    2011-01-01

    Butyric acid oriented production via anaerobic fermentation is a desirable pathway to the recycling treatment of blue-green algae. In the study four different pretreatment methodsnamely acidalkalineheat and microwave were used to enhance the fermentation. The content of butyric acid and total organic acids produced from pretreated blue-green algae was evaluated. The results indicated that all pretreatments enhanced the t the production of butyric acid and total organic acids. Among of themalkaline pretreatment at pH 10 exhibited the highest production of butyric acid and total organic acids from the blue-green algae feedstockthe value achieved at 4390 mg/L and 5962 mg/L respectively which both doubled as compared to that before pretreatment.%蓝藻厌氧发酵定向产丁酸是蓝藻资源化处置的理想方式.作者选择4种操作简单易行的预处理方法,即酸法、碱法、加热和微波法对蓝藻进行预处理,考察处理后蓝藻厌氧发酵的丁酸和有机酸产量.结果表明,各预处理方法均能不同程度地提高蓝藻厌氧发酵过程中的丁酸产量和有机酸产量.其中蓝藻经过pH 10碱性预处理后调节初始pH 5.0厌氧发酵的丁酸及有机酸产量最高,分别为4390 mg/L和5962 mg/L,比空白提高了近1倍.

  5. Essential metal depletion in an anaerobic reactor.

    NARCIS (Netherlands)

    Osuna, M.B.; Iza, J.M.; Zandvoort, M.H.; Lens, P.N.L.

    2003-01-01

    The effect of the absence of trace elements on the conversion of a mixture of volatile fatty acids by a distillery anaerobic granular sludge was investigated. Two UASB reactors were operated under identical operational conditions except for the influent trace metal concentrations, during 140 days. E

  6. Anaerobic microbial LCFA degradation in bioreactors

    NARCIS (Netherlands)

    Sousa, D.Z.; Pereira, M.A.; Alves, J.I.; Smidt, H.; Stams, A.J.M.; Alves, M.M.

    2008-01-01

    This paper reviews recent results obtained on long-chain fatty acids (LCFA) anaerobic degradation. Two LCFA were used as model substrates: oleate, a mono-unsaturated LCFA, and palmitate, a saturated LCFA, both abundant in LCFA-rich wastewaters. 16S rRNA gene analysis of sludge samples submitted to c

  7. Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery

    Science.gov (United States)

    Feuille, Catherine M.; Starke, Carly Elizabeth C.; Bhagwat, Arvind A.; Stibitz, Scott; Kopecko, Dennis J.

    2016-01-01

    The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues. However, the ECC was selected as a more practical delivery format for both packaging/shipping and vaccine administration ease. We have sought to increase Ty21a acid-resistance to allow for removal from the ECC and immune enhancement. To improve Ty21a acid-resistance, glutamate-dependent acid resistance genes (GAD; responsible for Shigella spp. survival at very low pH) were cloned on a multi-copy plasmid (pGad) under a controllable arabinose-inducible promoter. pGad enhanced acid survival of Ty21a by 5 logs after 3 hours at pH 2.5, when cells were pre-grown in arabinose and under conditions that promote an acid-tolerance response (ATR). For genetically 100% stable expression, we inserted the gad genes into the Ty21a chromosome, using a method that allowed for subsequent removal of a selectable antibiotic resistance marker. Further, both bacterial growth curves and survival assays in cultured human monocytes/macrophages suggest that neither the genetic methods employed nor the resulting acid-resistance conferred by expression of the Gad proteins in Ty21a had any effect on the existing attenuation of this vaccine strain. PMID:27673328

  8. Potent activity of the lichen antibiotic (+)-usnic acid against clinical isolates of vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus

    Science.gov (United States)

    Elo, Hannu; Matikainen, Jorma; Pelttari, Eila

    2007-06-01

    Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci, most notably methicillin-resistant Staphylococcus aureus (MRSA), are serious clinical problems. The antibiotic arsenal available against them is limited, and new mutants worsen the situation. We studied the activity of (+)-usnic acid, an old lichen-derived drug, and its sodium salt against clinical isolates of VRE and MRSA using the agar diffusion and minimal inhibitory concentration (MIC) methods. The acid and, especially, the sodium salt had potent antimicrobial activity against all clinical isolates of VRE and MRSA studied. The MIC values of the sodium salt against VRE strains ranged between 4 and 16 μg/ml (1-day test) and between 4 and 31 μg/ml (2-day test), being below 8 μg/ml for most strains. The salt had potent activity even against those strains that were not inhibited by ampicillin (125 μg/ml), and it never lost its activity after 24 h, in contrast to ampicillin. Thus, in spite of the fact that usnic acid can in some cases cause serious toxicity, it and its salts may be worth considering in clinical practice in cases where other therapies have failed or the microbe is resistant toward other agents.

  9. Protective Effect of Vanillic Acid against Hyperinsulinemia, Hyperglycemia and Hyperlipidemia via Alleviating Hepatic Insulin Resistance and Inflammation in High-Fat Diet (HFD)-Fed Rats

    OpenAIRE

    Wen-Chang Chang; James Swi-Bea Wu; Chen-Wen Chen; Po-Ling Kuo; Hsu-Min Chien; Yuh-Tai Wang; Szu-Chuan Shen

    2015-01-01

    Excess free fatty acid accumulation from abnormal lipid metabolism results in the insulin resistance in peripheral cells, subsequently causing hyperinsulinemia, hyperglycemia and/or hyperlipidemia in diabetes mellitus (DM) patients. Herein, we investigated the effect of phenolic acids on glucose uptake in an insulin-resistant cell-culture model and on hepatic insulin resistance and inflammation in rats fed a high-fat diet (HFD). The results show that vanillic acid (VA) demonstrated the highes...

  10. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  11. Fungal biotransformation of chlorogenic and caffeic acids by Fusarium graminearum: New insights in the contribution of phenolic acids to resistance to deoxynivalenol accumulation in cereals.

    Science.gov (United States)

    Gauthier, Léa; Bonnin-Verdal, Marie-Noelle; Marchegay, Gisèle; Pinson-Gadais, Laetitia; Ducos, Christine; Richard-Forget, Florence; Atanasova-Penichon, Vessela

    2016-03-16

    Fusarium Head Blight and Gibberella Ear Rot, mainly caused by the fungi Fusarium graminearum and Fusarium culmorum, are two of the most devastating diseases of small-grain cereals and maize. In addition to yield loss, these diseases frequently result in contamination of kernels with toxic type B trichothecenes. The potential involvement of chlorogenic acid in cereal resistance to Fusarium Head Blight and Gibberella Ear Rot and to trichothecene accumulation was the focus of this study. The effects of chlorogenic acid and one of its hydrolyzed products, caffeic acid, on fungal growth and type B trichothecenes biosynthesis were studied using concentrations close to physiological amounts quantified in kernels and a set of F. graminearum and F. culmorum strains. Both chlorogenic and caffeic acids negatively impact fungal growth and mycotoxin production, with caffeic acid being significantly more toxic. Inhibitory efficiencies of both phenolic acids were strain-dependent. To further investigate the antifungal and anti "mycotoxin" effect of chlorogenic and caffeic acids, the metabolic fate of these two phenolic acids was characterized in supplemented F. graminearum broths. For the first time, our results demonstrated the ability of F. graminearum to degrade chlorogenic acid into caffeic, hydroxychlorogenic and protocatechuic acids and caffeic acid into protocatechuic and hydroxycaffeic acids. Some of these metabolic products can contribute to the inhibitory efficiency of chlorogenic acid that, therefore, can be compared as a "pro-drug". As a whole, our data corroborate the contribution of chlorogenic acid to the chemical defense that cereals employ to counteract F. graminearum and its production of mycotoxins.

  12. Systematic identification of genes involved in metabolic acid stress resistance in yeast and their potential as cancer targets

    Directory of Open Access Journals (Sweden)

    John J. Shin

    2016-09-01

    Full Text Available A hallmark of all primary and metastatic tumours is their high rate of glucose uptake and glycolysis. A consequence of the glycolytic phenotype is the accumulation of metabolic acid; hence, tumour cells experience considerable intracellular acid stress. To compensate, tumour cells upregulate acid pumps, which expel the metabolic acid into the surrounding tumour environment, resulting in alkalization of intracellular pH and acidification of the tumour microenvironment. Nevertheless, we have only a limited understanding of the consequences of altered intracellular pH on cell physiology, or of the genes and pathways that respond to metabolic acid stress. We have used yeast as a genetic model for metabolic acid stress with the rationale that the metabolic changes that occur in cancer that lead to intracellular acid stress are likely fundamental. Using a quantitative systems biology approach we identified 129 genes required for optimal growth under conditions of metabolic acid stress. We identified six highly conserved protein complexes with functions related to oxidative phosphorylation (mitochondrial respiratory chain complex III and IV, mitochondrial tRNA biosynthesis [glutamyl-tRNA(Gln amidotransferase complex], histone methylation (Set1C–COMPASS, lysosome biogenesis (AP-3 adapter complex, and mRNA processing and P-body formation (PAN complex. We tested roles for two of these, AP-3 adapter complex and PAN deadenylase complex, in resistance to acid stress using a myeloid leukaemia-derived human cell line that we determined to be acid stress resistant. Loss of either complex inhibited growth of Hap1 cells at neutral pH and caused sensitivity to acid stress, indicating that AP-3 and PAN complexes are promising new targets in the treatment of cancer. Additionally, our data suggests that tumours may be genetically sensitized to acid stress and hence susceptible to acid stress-directed therapies, as many tumours accumulate mutations in mitochondrial

  13. Systematic identification of genes involved in metabolic acid stress resistance in yeast and their potential as cancer targets.

    Science.gov (United States)

    Shin, John J; Aftab, Qurratulain; Austin, Pamela; McQueen, Jennifer A; Poon, Tak; Li, Shu Chen; Young, Barry P; Roskelley, Calvin D; Loewen, Christopher J R

    2016-09-01

    A hallmark of all primary and metastatic tumours is their high rate of glucose uptake and glycolysis. A consequence of the glycolytic phenotype is the accumulation of metabolic acid; hence, tumour cells experience considerable intracellular acid stress. To compensate, tumour cells upregulate acid pumps, which expel the metabolic acid into the surrounding tumour environment, resulting in alkalization of intracellular pH and acidification of the tumour microenvironment. Nevertheless, we have only a limited understanding of the consequences of altered intracellular pH on cell physiology, or of the genes and pathways that respond to metabolic acid stress. We have used yeast as a genetic model for metabolic acid stress with the rationale that the metabolic changes that occur in cancer that lead to intracellular acid stress are likely fundamental. Using a quantitative systems biology approach we identified 129 genes required for optimal growth under conditions of metabolic acid stress. We identified six highly conserved protein complexes with functions related to oxidative phosphorylation (mitochondrial respiratory chain complex III and IV), mitochondrial tRNA biosynthesis [glutamyl-tRNA(Gln) amidotransferase complex], histone methylation (Set1C-COMPASS), lysosome biogenesis (AP-3 adapter complex), and mRNA processing and P-body formation (PAN complex). We tested roles for two of these, AP-3 adapter complex and PAN deadenylase complex, in resistance to acid stress using a myeloid leukaemia-derived human cell line that we determined to be acid stress resistant. Loss of either complex inhibited growth of Hap1 cells at neutral pH and caused sensitivity to acid stress, indicating that AP-3 and PAN complexes are promising new targets in the treatment of cancer. Additionally, our data suggests that tumours may be genetically sensitized to acid stress and hence susceptible to acid stress-directed therapies, as many tumours accumulate mutations in mitochondrial respiratory chain

  14. Biologic treatment of wastewater from cassava flour production using vertical anaerobic baffled reactor (VABR

    Directory of Open Access Journals (Sweden)

    Gleyce T Correia

    2008-08-01

    Full Text Available The estimate cassava production in Brazil in 2007 was of 25 million tons (= 15% of the world production and most of it is used in the production of flour. During its processing, waste that can cause environmental inequality is generated, if discharged inappropriately. One of the liquid waste generated, manipueira, is characterized by its high level of organic matter. The anaerobic treatment that uses a vertical anaerobic baffled reactor (VABR inoculated with granulated sludge, is one of the ways of treating this effluent. The anaerobic biodigestion phases are separated in this kind of reactor, allowing greater stability and resistance to load shocks. The VABR was built with a width/height rate of 1:2. The pH, acidity, alkalinity, turbidity and COD removal were analyzed in 6 different regions of the reactor, which was operated with an increasing feeding from ? 2000 to ? 10000 mg COD L?¹ and HRT between 6.0 and 2.5 days. The VABR showed decreasing acidity and turbidity, an increase in alkalinity and pH, and 96% efficiency in COD removal with 3-day HRT and feeding of 3800 mg COD L?¹.

  15. 膨润土改善鸡粪厌氧消化产酸产甲烷特性%Improving production characteristics of methane and organic acid during anaerobic batch digestion of poultry manure by adding bentonite

    Institute of Scientific and Technical Information of China (English)

    潘君廷; 马俊怡; 郜天磊; 邱凌; 刘宏斌

    2016-01-01

    There were approximately 20 billion chickens in the world in 2010, with 23% of the chicken population found in China. In 2009, the rapid development of chicken farms in China resulted in the production of 126 million tons of poultry manure. If managed inappropriately, poultry manure can cause serious environmental problems by polluting water, air, and soil. Anaerobic digestion is a complex bioconversion process that can treat organic waste and generate biogas with a high methane content that can be used as renewable energy, hence reducing the consumption of fossil fuel and curtailing greenhouse gas emissions. Ca2+-betonite is an environmental friendly material and is widely used in compost, heavy metal removal, pollutant adsorption, etc. In order to investigate the effect of betonite addition on anaerobic digestion of poultry manure, an orthogonal experiment L8(23)was conducted to determine amount of poultry manure (organic loading rate (OLR)), amount of bentonite and inoculum concentration on characteristics of methane production and organic acid production during anaerobic batch digestion of poultry manure under mesophilic condition (35±1)℃. The results showed that bentonite addition could significantly increase methane production per VS by 22.72% and 27.72% with 3.0% and 1.5% betonite addition (based on poultry manure total solids), respectively compared to the control group under low OLR condition. Methane production from poultry manure with 3.0% or 1.5% betonite addition had no significant (P>0.05) difference under low OLR condition. Specifically, methane production could be very significantly (P<0.05) increased by adding betonite under high OLR condition. Methane production was increased by 78.68% and 55.41% with 3.0% and 1.5% betonite addition, respectively, compared to the control group under high OLR condition. Methane production from poultry manure with 3.0% or 1.5% betonite addition had significant (P<0.05) difference under high OLR condition. In the

  16. NPM and BRG1 Mediate Transcriptional Resistance to Retinoic Acid in Acute Promyelocytic Leukemia.

    Science.gov (United States)

    Nichol, Jessica N; Galbraith, Matthew D; Kleinman, Claudia L; Espinosa, Joaquín M; Miller, Wilson H

    2016-03-29

    Perturbation in the transcriptional control of genes driving differentiation is an established paradigm whereby oncogenic fusion proteins promote leukemia. From a retinoic acid (RA)-sensitive acute promyelocytic leukemia (APL) cell line, we derived an RA-resistant clone characterized by a block in transcription initiation, despite maintaining wild-type PML/RARA expression. We uncovered an aberrant interaction among PML/RARA, nucleophosmin (NPM), and topoisomerase II beta (TOP2B). Surprisingly, RA stimulation in these cells results in enhanced chromatin association of the nucleosome remodeler BRG1. Inhibition of NPM or TOP2B abrogated BRG1 recruitment. Furthermore, NPM inhibition and targeting BRG1 restored differentiation when combined with RA. Here, we demonstrate a role for NPM and BRG1 in obstructing RA differentiation and implicate chromatin remodeling in mediating therapeutic resistance in malignancies. NPM mutations are the most common genetic change in patients with acute leukemia (AML); therefore, our model may be applicable to other more common leukemias driven by NPM.

  17. Proteomic analysis of salicylic acid induced resistance to Mungbean Yellow Mosaic India Virus in Vigna mungo.

    Science.gov (United States)

    Kundu, Subrata; Chakraborty, Dipjyoti; Pal, Amita

    2011-03-01

    The role of salicylic acid (SA) in inducing resistance to MYMIV infection in Vigna mungo has been elucidated by proteomics. Twenty-nine proteins identified by MALDI-TOF/TOF, predicted to be involved in stress responses, metabolism, photosynthesis, transport and signal transduction, showed increased abundance upon SA treatment. Susceptible plants showed characteristic yellow mosaic symptoms upon MYMIV infection. A concentration dependent decrease in physiological symptoms associated with MYMIV was observed upon exogenous SA treatment prior to viral inoculation; and no visible symptom was observed at 100 μM SA. SA treatment stimulated SOD and GPX activity and inhibited CAT activity thus preventing ROS mediated damage. Significant increase in chlorophyll, protein, carbohydrate, phenolic content and H(2)O(2) were observed. Involvement of calmodulin for transmission of defense signal by SA is suggested. A metabolic reprogramming leading to enhanced synthesis of proteins involved in primary and secondary metabolisms is necessary for SA mediated resistance to MYMIV. Identification of proteins showing increased abundance, involved in photosynthetic process is a significant finding which restores virus-induced degradation of the photosynthetic apparatus and provides enhanced metabolites required for repartition of resources towards defense.

  18. Antagonistic rhizobacteria and jasmonic acid induce resistance against tomato bacterial spot

    Directory of Open Access Journals (Sweden)

    Hélvio Gledson Maciel Ferraz

    2015-12-01

    Full Text Available AbstractTomato bacterial spot on tomato may be caused by four species of Xanthomonas and among them X. gardneri(Xg is the most destructive one, especially in areas irrigated using a center pivot system in Minas Gerais state and the midwest region of Brazil. Due to the ineffectiveness of chemical control and the lack of cultivars with high levels of genetic resistance, this study investigated the potential of three antagonists (Streptomyces setonii (UFV618, Bacillus cereus (UFV592 and Serratia marcescens (UFV252, and the hormone jasmonic acid (JA as a positive control, to reduce bacterial spot symptoms and to potentiate defense enzymes in the leaves of tomato plants infected by Xg. Tomato seeds were microbiolized with each antagonist, and the soil was drenched with these bacteria. The plants were sprayed with JA 48 h before Xginoculation. The final average severity on the tomato plants was reduced by 29.44, 59.26 and 61.33% in the UFV592, UFV618 and JA treatments, respectively. The UFV618 antagonist was as effective as JA in reducing bacterial spot symptoms on tomatoes, which can be explained by the greater activities of defense enzymes that are commonly involved in host resistance against bacterial diseases. These results suggest that JA and the UFV618 antagonist can be used in the integrated management of bacterial spot on tomatoes.

  19. Multifunctional hyaluronic acid modified graphene oxide loaded with mitoxantrone for overcoming drug resistance in cancer

    Science.gov (United States)

    Hou, Lin; Feng, Qianhua; Wang, Yating; Yang, Xiaomin; Ren, Junxiao; Shi, Yuyang; Shan, Xiaoning; Yuan, Yujie; Wang, Yongchao; Zhang, Zhenzhong

    2016-01-01

    Multifunctional nanosheets (HA-GO/Pluronic) with targeted chemo-photothermal properties were successfully developed for controlled delivery of mitoxantrone (MIT) to overcome multidrug resistance (MDR). In vitro release profiles displayed that both an acidic environment and a NIR laser could trigger and accelerate the release of a drug, which ensured nanosheets were stable in blood circulation and released MIT within tumor cells under laser irradiation. HA-GO/Pluronic nanosheets were taken up into MCF-7/ADR cells via receptor-mediated endocytosis, which further facilitated escapement of P-gp efflux. Compared with MIT solution, MIT/HA-GO/Pluronic showed greater cytotoxicity and increase in cellular MIT accumulation in MCF-7/ADR cells. Cell apoptosis and cell cycle arrest studies also revealed that MIT/HA-GO/Pluronic was more potent than MIT/GO/Pluronic and MIT solution. The anticancer efficacy in vivo was evaluated in MCF-7 and MCF-7/ADR-bearing mice, and inhibition of tumors by MIT/HA-GO/Pluronic with NIR laser irradiation was the most effective among all MIT formulations. In summary, the MIT/HA-GO/Pluronic system had striking functions such as P-gp reversible inhibitor and anticancer efficacy, and could present a promising platform for drug-resistant cancer treatment.

  20. Induced resistance against the Asian citrus psyllid, Diaphorina citri, by β-aminobutyric acid in citrus.

    Science.gov (United States)

    Tiwari, Siddharth; Meyer, Wendy L; Stelinski, Lukasz L

    2013-10-01

    β-Aminobutyric acid (BABA) is known to induce resistance to microbial pathogens, nematodes and insects in several host plant/pest systems. The present study was undertaken to determine whether a similar effect of BABA occurred against the Asian citrus psyllid, Diaphorina citri Kuwayama, in citrus. A 25 mM drench application of BABA significantly reduced the number of eggs/plant as compared with a water control, whereas 200 and 100 mM applications of BABA reduced the numbers of nymphs/plant and adults/plants, respectively. A 5 mM foliar application of BABA significantly reduced the number of adults but not eggs or nymphs when compared with a water control treatment. In addition, leaf-dip bioassays using various concentrations (25–500 mM) of BABA indicated no direct toxic effect on 2nd and 5th instar nymphs or adult D. citri. BABA-treated plants were characterized by significantly lower levels of iron, magnesium, phosphorus, sodium, sulfur and zinc as compared with control plants. The expression level of the PR-2 gene (β-1,3-glucanase) in BABA-treated plants that were also damaged by D. citri adult feeding was significantly higher than in plants exposed to BABA, D. citri feeding alone or control plants. Our results indicate the potential for using BABA as a systemic acquired resistance management tool for D. citri.

  1. Role of a single amino acid substitution of VP3 H142D for increased acid resistance of foot-and-mouth disease virus serotype A.

    Science.gov (United States)

    Biswal, Jitendra K; Das, Biswajit; Sharma, Gaurav K; Khulape, Sagar A; Pattnaik, Bramhadev

    2016-04-01

    Foot-and-mouth disease virus (FMDV) particles lose infectivity due to their dissociation into pentamers at pH value below 6.5. After the uptake of FMDV by receptor-mediated endocytosis, the acid-dependent dissociation process is required for the release of FMDV genome inside endosomes. Nevertheless, dissociation of FMDV particles in mildly acidic conditions renders the inactivated FMD vaccine less effective. To improve the acid stability of inactivated FMD vaccine during the manufacturing process, a serotype A IND 40/2000 (in-use vaccine strain) mutant with increased resistance to acid inactivation was generated through reverse genetics approach. Based upon the earlier reports, the crucial amino acid residue, H142 of VP3 capsid protein was substituted separately to various amino acid residues Arg (R), Phe (F), Ala (A), and Asp (D) on the full-genome length cDNA clone. While the H142 → R or H142 → F or H142 → A substitutions resulted in non-infectious FMDV, H142 → D mutation on VP3 protein (H3142D) resulted in the generation of mutant virus with enhanced resistance to acid-induced inactivation. In addition, H3142D substitution did not alter the replication ability and antigenicity of mutant as compared to the parental virus. However, the virus competition experiments revealed that the H3142D substitution conferred a loss of fitness for the mutant virus. Results from this study demonstrate that the H3142D substitution is the molecular determinant of acid-resistant phenotype in FMDV serotype A. PMID:26873406

  2. The effects of a pre-workout supplement containing caffeine, creatine, and amino acids during three weeks of high-intensity exercise on aerobic and anaerobic performance

    Directory of Open Access Journals (Sweden)

    Kendall Kristina L

    2010-02-01

    Full Text Available Abstract Background A randomized, single-blinded, placebo-controlled, parallel design study was used to examine the effects of a pre-workout supplement combined with three weeks of high-intensity interval training (HIIT on aerobic and anaerobic running performance, training volume, and body composition. Methods Twenty-four moderately-trained recreational athletes (mean ± SD age = 21.1 ± 1.9 yrs; stature = 172.2 ± 8.7 cm; body mass = 66.2 ± 11.8 kg, VO2max = 3.21 ± 0.85 l·min-1, percent body fat = 19.0 ± 7.1% were assigned to either the active supplement (GT, n = 13 or placebo (PL, n = 11 group. The active supplement (Game Time®, Corr-Jensen Laboratories Inc., Aurora, CO was 18 g of powder, 40 kcals, and consisted of a proprietary blend including whey protein, cordyceps sinensis, creatine, citrulline, ginseng, and caffeine. The PL was also 18 g of powder, 40 kcals, and consisted of only maltodextrin, natural and artificial flavors and colors. Thirty minutes prior to all testing and training sessions, participants consumed their respective supplements mixed with 8-10 oz of water. Both groups participated in a three-week HIIT program three days per week, and testing was conducted before and after the training. Cardiovascular fitness (VO2max was assessed using open circuit spirometry (Parvo-Medics TrueOne® 2400 Metabolic Measurement System, Sandy, UT during graded exercise tests on a treadmill (Woodway, Pro Series, Waukesha, WI. Also, four high-speed runs to exhaustion were conducted at 110, 105, 100, and 90% of the treadmill velocity recorded during VO2max, and the distances achieved were plotted over the times-to-exhaustion. Linear regression was used to determine the slopes (critical velocity, CV and y-intercepts (anaerobic running capacity, ARC of these relationships to assess aerobic and anaerobic performances, respectively. Training volumes were tracked by summing the distances achieved during each training session for each subject

  3. Long-term fatty liver-induced insulin resistance in orotic acid-induced nonalcoholic fatty liver rats.

    Science.gov (United States)

    Han, Xiuqing; Liu, Chunhua; Xue, Yong; Wang, Jingfeng; Xue, Changhu; Yanagita, Teruyoshi; Gao, Xiang; Wang, Yuming

    2016-01-01

    We investigated whether fatty liver preceded insulin resistance or vice versa using a long-term orotic acid (OA)-induced nonalcoholic fatty liver disease (NAFLD) model without the confounding effects of obesity and hyperlipidemia and explored the role of the liver in insulin resistance. Male Wistar rats were fed with or without OA supplementation for 30, 60, and 90 days. The NAFLD group showed increased liver lipid at 30, 60, and 90 days; glucose intolerance was noted at 60 and 90 days. Furthermore, partial liver proteins and gene expressions related to upstream signaling of insulin were decreased. However, the liver glycogen content was elevated, and gluconeogenesis genes expressions were obviously decreased at 90 days. The occurrence of fatty liver preceded insulin resistance in OA-induced NAFLD without the interference of obesity and hyperlipidemia, and hepatic insulin resistance may not play a conclusive role in insulin resistance in this model. PMID:26775542

  4. Anaerobic treatment of wastewater containing methanol in upflow anaerobic sludge bed (UASB) reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater.However,acetic acid can also be produced from methanol theoretically,which may probably result in an abrupt pH drop and deteriorate the anaerobic process.Therefore,it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater.In this study,an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated.The chemical oxygen demand (COD),acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity.The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops.Volatile fatty acids accumulation was not observed even at strong shock loadings.The microorganisms in the sludge at the end of the test became homogeneous in morphology,which were mainly spherical or spheroidal in shape.

  5. Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics.

    Science.gov (United States)

    Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

    2015-12-22

    Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

  6. Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

    Science.gov (United States)

    Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

    2015-12-01

    Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

  7. Acid resistance and response to pH-induced stress in two Lactobacillus plantarum strains with probiotic potential.

    Science.gov (United States)

    Šeme, H; Gjuračić, K; Kos, B; Fujs, Š; Štempelj, M; Petković, H; Šušković, J; Bogovič Matijašić, B; Kosec, G

    2015-01-01

    Two new Lactobacillus plantarum strains, KR6-DSM 28780 and M5 isolated from sour turnip and traditional dried fresh cheese, respectively, were evaluated for species identity, antibiotic susceptibility, resistance to gastrointestinal conditions and adaptive response to low pH. Resistance mechanisms involved in the adaptation to acid-induced stress in these two strains were investigated by quantitative PCR of the atpA, cfa1, mleS and hisD genes. In addition to absence of antibiotic resistance, the two L. plantarum strains showed excellent survival rates at pH values as low as 2.4. Adaptive response to low pH was clearly observed in both strains; strain KR6 was superior to M5, as demonstrated by its ability to survive during 3 h incubation at pH 2.0 upon adaptation to moderately acidic conditions. In contrast, acid adaptation did not significantly affect the survival rate during simulated passage through the gastrointestinal tract. In both strains, induction of histidine biosynthesis (hisD) was upregulated during the acid adaptation response. In addition, significant upregulation of the cfa1 gene, involved in modulation of membrane fatty acid composition, was observed during the adaptation phase in strain KR6 but not in strain M5. Cells adapted to moderately acidic conditions also showed a significantly increased viability after the lyophilisation procedure, a cross-protection phenomenon providing additional advantage in probiotic application.

  8. 挥发性有机酸对产沼气效果的模拟试验%Simulation experiment of volatility organic acids on biogas-producing characteristics under anaerobic condition

    Institute of Scientific and Technical Information of China (English)

    董保成; 赵立欣; 万小春; 罗娟; 陈羚; 高新星

    2011-01-01

    两相厌氧生物处理工艺在废弃物资源化利用中得到广泛应用.为了摸清产酸相的主要产物在产气过程中的效应,该文利用甲酸、乙酸、丙酸和丁酸等4种有机酸模拟产酸过程中的主要酸化产物,以活性污泥为接种物,设计单因素试验和正交试验,研究了在中温条件下,4种有机酸单一作用条件下和混合作用条件下,甲烷日产气量和累积产气量的变化.结果表明:单一有机酸作底物时,存在一个浓度阈值,高于此值会抑制甲烷产生,低于此值,产气效果随着酸浓度增大而提高;有机酸共同存在时,可以产生协同优势,其中乙酸的产气优势高于丁酸,丙酸具有抑制作用;4种单一酸中,单位浓度下乙酸产气效果最好,甲酸产气量最大,甲酸积累不易对发酵过程产生抑制作用,而丙酸累积最易造成抑制.因此,建议在沼气工程中适当调整产甲酸、乙酸和丁酸较多的发酵物料浓度,从而提高产气效率.%Two-phase anaerobic biological treatment has been widely applied in waste disposal/utilization. In order to study the effects of main products on the biogas-producing process, based on the simulation of four major acidified organic acids (formic acid, acetic acid, propionic acid and butyric acid), the activated sludge was inoculated. Then single factor and orthogonal experiments were designed to study the main and interactive effects of organic acids on dynamics of both daily and accumulative methane production under medium temperature condition. The results showed that there existed a critical threshold of organic acid concentration in single organic acid, where high concentration above the threshold would have inhibited effect on gas production; and gas production got increased with the acid concentration increasing when it below the threshold. There was a significant interactive effect among the four organic acids, and acetic acid had the stronger increasing effect than

  9. Amino acid substitutions in the thymidine kinase gene of induced acyclovir-resistant herpes simplex virus type 1

    Science.gov (United States)

    Hussin, Ainulkhir; Nor, Norefrina Shafinaz Md; Ibrahim, Nazlina

    2013-11-01

    Acyclovir (ACV) is an antiviral drug of choice in healthcare setting to treat infections caused by herpes viruses, including, but not limited to genital herpes, cold sores, shingles and chicken pox. Acyclovir resistance has emerged significantly due to extensive use and misuse of this antiviral in human, especially in immunocompromised patients. However, it remains unclear about the amino acid substitutions in thymidine (TK) gene, which specifically confer the resistance-associated mutation in herpes simplex virus. Hence, acyclovir-resistant HSV-1 was selected at high concentration (2.0 - 4.5 μg/mL), and the TK-gene was subjected to sequencing and genotypic characterization. Genotypic sequences comparison was done using HSV-1 17 (GenBank Accesion no. X14112) for resistance-associated mutation determination whereas HSV-1 KOS, HSV-1 473/08 and HSV clinical isolates sequences were used for polymorphism-associated mutation. The result showed that amino acid substitutions at the non-conserved region (UKM-1: Gln34Lys, UKM-2: Arg32Ser & UKM-5: Arg32Cys) and ATP-binding site (UKM-3: Tyr53End & UKM-4: Ile54Leu) of the TK-gene. These discoveries play an important role to extend another dimension to the evolution of acyclovir-resistant HSV-1 and suggest that selection at high ACV concentration induced ACV-resistant HSV-1 evolution. These findings also expand the knowledge on the type of mutations among acyclovir-resistant HSV-1. In conclusion, HSV-1 showed multiple strategies to exhibit acyclovir resistance, including amino acid substitutions in the TK gene.

  10. Tolerance and accumulation of shikimic acid in response to glyphosate applications in glyphosate-resistant and nonglyphosate-resistant cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Pline, Wendy A; Wilcut, John W; Duke, Stephen O; Edmisten, Keith L; Wells, Randy

    2002-01-30

    Measurement of shikimic acid accumulation in response to glyphosate inhibition of 5-enolpyruvylshikimate-3-phosphate synthase is a rapid and accurate assay to quantify glyphosate-induced damage in sensitive plants. Two methods of assaying shikimic acid, a spectrophotometric and a high-performance liquid chromatography (HPLC) method, were compared for their accuracy of recovering known amounts of shikimic acid spiked into plant samples. The HPLC method recovered essentially 100% of shikimic acid as compared with only 73% using the spectrophotometric method. Relative sensitivity to glyphosate was measured in glyphosate-resistant (GR) and non-GR cotton leaves, fruiting branches, and squares (floral buds) by assaying shikimic acid. Accumulation of shikimic acid was not observed in any tissue, either GR or non-GR, at rates of 5 mM glyphosate or less applied to leaves. All tissues of non-GR plants accumulated shikimic acid in response to glyphosate treatment; however, only fruiting branches and squares of GR plants accumulated a slight amount of shikimic acid. In non-GR cotton, fruiting branches and squares accumulated 18 and 11 times, respectively, more shikimic acid per micromolar of translocated glyphosate than leaf tissue, suggesting increased sensitivity to glyphosate of reproductive tissue over vegetative tissue. GR cotton leaves treated with 80 mM of glyphosate accumulated 57 times less shikimic acid per micromolar of translocated glyphosate than non-GR cotton but only 12.4- and 4-fold less in fruiting branches and squares, respectively. The increased sensitivity of reproductive structures to glyphosate inhibition may be due to a higher demand for shikimate pathway products and may provide an explanation for reports of fruit abortion from glyphosate-treated GR cotton.

  11. ISOLATION OF ANAEROBES IN DEEP SEATED PRESSURE ULCERS USING A NOVEL INNOVATIVE TECHNIQUE OF ANAEROBE ISOLATION

    Directory of Open Access Journals (Sweden)

    Lalbiaktluangi

    2015-12-01

    Full Text Available BACKGROUND Isolation of an anaerobe is usually neglected in hospitals with limited resources due to the expensive and complicated technique of anaerobic isolation methods, which is difficult to arrange in such resource poor settings. Conventionally adopted anaerobic culture methods such as Anaerobic jar, Gas-Pak, Anoxomat or Automated glove-box systems are extremely costly and cumbersome for single unit testing, but not suitable for small scale laboratories. However, anaerobic bacteria are not to be overlooked as they have made a comeback in clinical settings and are even showing resistance to Metronidazole, once thought to be the gold standard bullet against anaerobes. Deep seated pressure ulcers are usually the site where anaerobe causes an infection in synergy with aerobes. AIMS AND OBJECTIVES Isolation of anaerobes in deep seated pressure ulcers using a novel innovative technique and to study their antibiogram profile. MATERIALS AND METHODS Swabs taken from depth of deep seated pressure ulcers were immediately inoculated in Brucella blood agar at bedside and placed in polycarbonate airtight jar for anaerobic incubation using a novel innovative Modified Candle Jar technique. In this technique five grams of grease-free grade zero steel wool were dipped in 50ml freshly prepared acidified copper sulphate solution until the copper colour appeared. Excess solution was drained and the steel wool was moulded into a loose pad to fit on an open Petri plate placed on top of the inoculated Brucella blood agar plates. A white-wax candle was placed at the centre of this plate. A small test tube containing mixture of 0.5g sodium-bicarbonate and 0.5g magnesium carbonate was kept ready to be placed inside the jar, just after placing the inoculated plate and incubated for 48 hours. RESULTS Peptostreptococcus anaerobius and Bacteroides fragilis were successfully isolated from deep seated pressure ulcers by this method. Antibiogram studies were done using the

  12. Influence of soil substrate and ozone plus acid mist on the frost resistance of young Norway spruce.

    Science.gov (United States)

    Senser, M

    1990-01-01

    The needles of clonal Norway spruce grown in environmental chambers on two different soils (an acidic soil 1 and a calcareous soil 2) and exposed to two levels of ozone fumigation (a low level combined with neutral mist = control, and an elevated one combined with acid mist = treatment) were analyzed for their frost hardiness. No effect of ozone was observed on either the development of frost resistance during the hardening phase or on the decrease in frost resistance during the dehardening phase. The preliminary results of Brown et al. (1987) and Barnes and Davidson (1988), which indicated that ozone treatment predisposes plants to winter injury, could thus not be confirmed. Frost resistance was, however, distinctly influenced by the content of the mineral nutrients of the soils. The pronounced K(+) deficiency of the needles of the trees growing on the neutral soil (Alps) had less effect on the development of frost resistance than did the Ca(++) and Mg(++) deficiency of the needles of the trees grown on the acidic soil 1 (Bavarian Forest). The variability of frost resistance between the different clones on soil 1 was partly attributed to fluctuations in the mineral nutrient content of the needles, rather than to a genetic predisposition. PMID:15092284

  13. In vitro and in vivo synergism between amoxicillin and clavulanic acid against ampicillin-resistant Haemophilus influenzae type b.

    OpenAIRE

    Yogev, R; Melick, C; Kabat, W J

    1981-01-01

    Eight strans of ampicillin-resistant beta-lactamase-producing Haemophilus influenzae type b were studied in vitro for synergy between amoxicillin and clavulanic acid. The minimal inhibitory concentrations for amoxicillin alone were 6.25 to 12.5 microgram/ml, and for clavulanic acid alone they were 12.5 to 25 microgram/ml. However, seven of eight strains were inhibited by a combination of 0.36 microgram of amoxicillin and 0.36 microgram of clavulanic acid per ml. Infant rat models of bacteremi...

  14. Structure of a novel multidrug resistance modulator, irciniasulfonic acid, isolated from a marine sponge, Ircinia sp.

    NARCIS (Netherlands)

    A. Kawakami; T. Miyamoto; R. Higuchi; T. Uchiumi; M. Kuwano; R.W.M. van Soest

    2001-01-01

    Irciniasulfonic acid was obtained from a marine sponge of Ircinia sp. Spectroscopic and chemical analyses revealed its structure consists of three different kinds of acids, i.e. common fatty acids, a novel unsaturated branched C-10 fatty acid and an isethionic acid. Irciniasulfonic acid and deacyl i

  15. Association of adiponectin,free fatty acids,and insulin resistance with metabolic syndrome and its components in Uygur Xinjiang

    Institute of Scientific and Technical Information of China (English)

    闫贻忠

    2014-01-01

    Objective To investigate the association of adiponectin(APN),free fatty acids(FFA),and insulin resistance(IR)with metabolic syndrome(MS)and its components.Methods In the baseline survey,the subjects were divided into MS group and the control group based

  16. Glyphosate-resistant and conventional canola (Brassica napus L.)responses to glyphosate and Aminomethylphosphonic Acid (AMPA) treatment

    Science.gov (United States)

    Glyphosate-resistant (GR) canola expresses two transgenes: 1) the microbial glyphosate oxidase gene (gox) encoding the glyphosate oxidase enzyme (GOX) that metabolizes glyphosate to aminomethylphosphonic acid (AMPA) and 2) cp4 that encodes a GR form of the glyphosate target enzyme 5-enolpyruvylshiki...

  17. Acquired resistance of Nocardia brasiliensis to clavulanic acid related to a change in beta-lactamase following therapy with amoxicillin-clavulanic acid.

    Science.gov (United States)

    Steingrube, V A; Wallace, R J; Brown, B A; Pang, Y; Zeluff, B; Steele, L C; Zhang, Y

    1991-01-01

    Previous studies have demonstrated that Nocardia brasiliensis is susceptible to amoxicillin-clavulanic acid and that its beta-lactamases are inhibited in vitro by clavulanic acid. A cardiac transplant patient with disseminated infection caused by N. brasiliensis was treated with this drug combination with good response, but relapsed while still on therapy. The relapse isolate was found to be identical to the initial isolate by using genomic DNA restriction fragment patterns obtained by pulsed field gel electrophoresis, but it was resistant to amoxicillin-clavulanic acid. On isoelectric focusing, the beta-lactamase from the relapse isolate exhibited a shift in the isoelectric point (pI) of its major band from 5.10 to 5.04 compared with the enzyme from the pretreatment isolate. As determined by using values of the amount of beta-lactamase inhibitor necessary to give 50 +/- 5% inhibition of beta-lactamase-mediated hydrolysis of 50 microM nitrocefin, the beta-lactamase of the relapse isolate was also 200-fold more resistant than the enzyme from the pretreatment isolate to clavulanic acid and was more resistant to sulbactam, tazobactam, cloxacillin, and imipenem. The beta-lactamase of the relapse isolate exhibited a 10-fold decrease in hydrolytic activity for cephaloridine and other hydrolyzable cephalosporins compared with that for nitrocefin. Acquired resistance to amoxicillin-clavulanic acid in this isolate of N. brasiliensis appears to have resulted from a mutational change affecting the inhibitor and active site(s) in the beta-lactamase. Images PMID:2039203

  18. Anaerobic infections in the head and neck region.

    Science.gov (United States)

    Tabaqchali, S

    1988-01-01

    Anaerobic bacteria form the predominant flora of the oral cavity, outnumbering facultative organisms by 10-1,000: 1. The type of anaerobic bacteria and their concentration depend on the anatomical site and the degree of anaerobiosis in the different sites in the mouth. Three groups of anaerobic bacteria inhabit the oral cavity; the strict anaerobes, the moderate anaerobes, and the microaerophilic group of organisms. The majority of anaerobic bacterial infections occurring in the region of the mouth, head and neck are caused by the commensal flora. These infections include dental and periodontal disease where the predominant organisms are Bacteroides species, Veillonella, Bifidobacteria, Peptococcus, Peptostreptococcus and Propionibacterium species. More recently, Bacteroides endontalis has been isolated from a periapical abscess of endodontal origin and B. gingivalis, B. intermedius, Haemophilus actinomycetemcomitans and Wollinella species in chronic periodontal disease. Treponema species and other strict anaerobes are seen in smears of severe periodontal disease and acute necrotising gingivitis, but have not yet been isolated in pure culture. Until such time, their role in disease remains uncertain. Fusobacterium nucleatum is specially associated with severe orofacial infections which may extend into the mediastinum. Other anaerobic infections include chronic otitis media, chronic sinusitis and mastoiditis, and brain abscess. Treatment of these conditions should include the use of beta-lactamase resistant antimicrobials, such as clindamycin or one of the nitroimidazoles with penicillin.

  19. Photoproduction of H2 from Cellulose by an Anaerobic Bacterial Coculture

    OpenAIRE

    Odom, James M.; Wall, Judy D.

    1983-01-01

    Cellulomonas sp. strain ATCC 21399 is a facultatively anaerobic, cellulose-degrading microorganism that does not evolve hydrogen but produces organic acids during cellulose fermentation. Rhodopseudomonas capsulata cannot utilize cellulose, but grows photoheterotrophically under anaerobic conditions on organic acids or sugars. This report describes an anaerobic coculture of the Cellulomonas strain with wild-type R. capsulata or a mutant strain lacking uptake hydrogenase, which photoevolves mol...

  20. EFFECT OF ASCORBIC ACID ON DNA SYNTHESIS, INTRACELLULAR ACCUMULATION OF ADM AND ADM RESISTANCE OF TUMOR CELL LINES

    Institute of Scientific and Technical Information of China (English)

    Xie Zuofu; Lin Xiandong; Zhou Dongmei; Lin Sheng

    1998-01-01

    Objective: To determine the effect of ascorbic acid (AA) on DNA synthesis, intracellular accumulation of ADM and ADM resistance of tumor cell lines.Methods: K562, K562/ADM and KB cell lines were used to study the effect of ascorbic acid on DNA synthesis,intracellular accumulation of ADM and ADM resistance by fluid scintillometry, MTT method, spectrofluorophotometry and immunocytochemistry. Results: Results showed that AA was capable of inhibiting DNA synthesis of K562 and K562/ADM in a dose-dependence fashion,but not KB cell line, and significantly reducing ADM sensitivity in K562 and KB cell lines, as well as potentiating obviously ADM resistance in K562/ADM cell line. Conclusion: These effects of AA may be closely correlated with significant elevation of intracellular accumulation of ADM in KB cell line, and significant reduction of that in K562 and K562/ADM cell lines but possibly not correlated with the expression of Pglycoprotein.

  1. Phytol/Phytanic Acid and Insulin Resistance: Potential Role of Phytanic Acid Proven by Docking Simulation and Modulation of Biochemical Alterations

    Science.gov (United States)

    Elmazar, Mohamed M.; El-Abhar, Hanan S.; Schaalan, Mona F.; Farag, Nahla A.

    2013-01-01

    Since activation of PPARγ is the main target for the antidiabetic effect of TZDs, especially when it heterodimerizes with RXR, we aimed to test the potential antidiabetic effect of phytol (250 mg/kg), the natural precursor of phytanic acid, a RXR ligand and/or pioglitazone (5 mg/kg) to diabetic insulin-resistant rats. Regarding the molecular docking simulation on PPARγ, phytanic acid, rather than phytol, showed a binding mode that mimics the crystal orientation of rosiglitazone and pioglitazone, forming H bonds with the same amino acids (S289, H 323, H 449 and Y 473), and the least energy level, which emphasizes their importance for PPARγ molecular recognition, activation, hence antidiabetic activity. In addition, docking on the RXRα/PPARγ heterodimer, revealed that phytanic acid has higher binding affinity and lesser energy score on RXRα, compared to the original ligand, retinoic acid. Phytanic acid binds by 3H bonds and shares retinoic acid in arginine (R 316). These results were further supported biochemically, where oral phytol and/or pioglitazone (5 mg/kg) improved significantly glucose homeostasis, lipid panel, raised serum adiponectin level and lowered TNF-α, reaching in most cases the effect of the 10 mg/kg pioglitazone. The study concluded that the insulin sensitizing/anti-diabetic effect of phytol is mediated by partly from activation of nuclear receptors and heterodimerization of RXR with PPARγ by phytanic acid. PMID:23300941

  2. Clostridium difficile: the anaerobe that made the grade.

    Science.gov (United States)

    Brazier, Jon S

    2012-04-01

    Unlike other anaerobic bacteria of clinical importance, Clostridium difficile has managed to enter into the realm of public awareness. Following the trail blazed by methicillin-resistant Staphylococcus aureus (MRSA), C. difficile has made the transition from being an obscure anaerobic bacterium, mainly of interest to specialist anaerobic microbiologists, to that of an infamous "superbug" responsible for outbreaks of hospital-acquired infection that commonly result in serious disease and death. This report picks out key moments, particularly in the UK, which tracked the rise in both the public and political awareness of this organism. PMID:22293217

  3. The Evaluation of the Role of Beta-Hydroxy Fatty Acids on Chronic Inflammation and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    A. S. Soydan

    2006-01-01

    Full Text Available β-hydroxy fatty acids are a major component of lipid A moiety of lipopolysaccaride. We aimed to investigate the role of free β-hydroxy fatty acids on inflammation, as well as to evaluate their effects on cytokine release from human blood cells, and whether they exist in plasma of patients with chronic inflammatory diseases with/without insulin resistance. Peripheral venous blood was incubated with β-hydroxy lauric and β-hydroxy myristic acids (each 100 ng, 1 μg, 10 μg/mL up to 24 hours. Cytokines were measured from culture media and plasma. Free fatty acids and biochemical parameters were also measured from patients' plasma. Only β-hydroxy lauric acid significantly stimulated interleukin-6 production at 10 μg/mL compared to control (533.9±218.1 versus 438.3±219.6 pg/mL, P<.05. However, free β-hydroxy lauric and myristic acids were not found in patients' plasma. Therefore, free β-hydroxy lauric and myristic acids do not seem to have a role on sterile inflammation in chronic inflammatory diseases associated with insulin resistance.

  4. A single amino acid substitution in isozyme GST mu in Triclabendazole resistant Fasciola hepatica (Sligo strain) can substantially influence the manifestation of anthelmintic resistance.

    Science.gov (United States)

    Fernández, V; Estein, S; Ortiz, P; Luchessi, P; Solana, V; Solana, H

    2015-12-01

    The helminth parasite Fasciola hepatica causes fascioliasis in human and domestic ruminants. Economic losses due to this infection are estimated in U$S 2000-3000 million yearly. The most common method of control is the use of anthelmintic drugs. However, there is an increased concern about the growing appearance of F. hepatica resistance to Triclabendazole (TCBZ), an anthelmintic with activity over adult and young flukes. F. hepatica has eight Glutathione S-Transferase (GST) isozymes, which are enzymes involved in the detoxification of a wide range of substrates through chemical conjugation with glutathione. In the present work we identified and characterized the GST mu gene isolated from the TCBZ-susceptible and TCBZ-resistant F. hepatica strains. Total RNA was transcribed into cDNA by reverse transcription and a 657 bp amplicon corresponding to the GST mu gene was obtained. The comparative genetic analysis of the GST mu gene of the TCBZ susceptible strain (Cullompton) and TCBZ resistant strain (Sligo) showed three nucleotide changes and one amino acid change at position 143 in the GST mu isozyme of the TCBZ-resistant strain. These results have potential relevance as they contribute better understand the mechanisms that generate resistance to anthelmintics.

  5. Efficient anaerobic treatment of synthetic textile wastewater in a UASB reactor with granular sludge enriched with humic acids supported on alumina nanoparticles.

    Science.gov (United States)

    Cervantes, Francisco J; Gómez, Rafael; Alvarez, Luis H; Martinez, Claudia M; Hernandez-Montoya, Virginia

    2015-07-01

    A novel technique to co-immobilize humus-reducing microorganisms and humic substances (HS), supported on γ-Al2O3 nanoparticles (NP), by a granulation process in an upflow anaerobic sludge bed (UASB) reactor is reported in the present work. Larger granules (predominantly between 1 and 1.7 mm) were produced using NP coated with HS compared to those obtained with uncoated NP (mostly between 0.25 and 0.5 mm). The HS-enriched granular biomass was then tested for its capacity to achieve the reductive decolorization of the recalcitrant azo dye, reactive red 2 (RR2), in the same UASB reactor operated with a hydraulic residence time of 12 h and with glucose as electron donor. HS-enriched granules achieved higher decolorization and COD removal efficiencies, as compared to the control reactor operated in the absence of HS, in long term operation and applying high concentrations of RR2 (40-400 mg/L). This co-immobilizing technique could be attractive for its application in UASB reactors for the reductive biotransformation of several contaminants, such as nitroaromatics, poly-halogenated compounds, metalloids, among others.

  6. Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein

    Directory of Open Access Journals (Sweden)

    Stout Jeffrey R

    2010-06-01

    Full Text Available Abstract Regardless of age or gender, resistance training or provision of adequate amounts of dietary protein (PRO or essential amino acids (EAA can increase muscle protein synthesis (MPS in healthy adults. Combined PRO or EAA ingestion proximal to resistance training, however, can augment the post-exercise MPS response and has been shown to elicit a greater anabolic effect than exercise plus carbohydrate. Unfortunately, chronic/adaptive response data comparing the effects of different protein sources is limited. A growing body of evidence does, however, suggest that dairy PRO, and whey in particular may: 1 stimulate the greatest rise in MPS, 2 result in greater muscle cross-sectional area when combined with chronic resistance training, and 3 at least in younger individuals, enhance exercise recovery. Therefore, this review will focus on whey protein supplementation and its effects on skeletal muscle mass when combined with heavy resistance training.

  7. Isoflavone, glyphosate, and aminomethylphosphonic acid levels in seeds of glyphosate-treated, glyphosate-resistant soybean.

    Science.gov (United States)

    Duke, Stephen O; Rimando, Agnes M; Pace, Patrick F; Reddy, Krishna N; Smeda, Reid J

    2003-01-01

    The estrogenic isoflavones of soybeans and their glycosides are products of the shikimate pathway, the target pathway of glyphosate. This study tested the hypothesis that nonphytotoxic levels of glyphosate and other herbicides known to affect phenolic compound biosynthesis might influence levels of these nutraceutical compounds in glyphosate-resistant soybeans. The effects of glyphosate and other herbicides were determined on estrogenic isoflavones and shikimate in glyphosate-resistant soybeans from identical experiments conducted on different cultivars in Mississippi and Missouri. Four commonly used herbicide treatments were compared to a hand-weeded control. The herbicide treatments were (1) glyphosate at 1260 g/ha at 3 weeks after planting (WAP), followed by glyphosate at 840 g/ha at 6 WAP; (2) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied preemergence (PRE), followed by glyphosate at 1260 g/ha at 6 WAP; (3) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by glyphosate at 1260 g/ha at full bloom; and (4) sulfentrazone at 168 g/ha plus chlorimuron at 34 g/ha applied PRE, followed by acifluorfen at 280 g/ha plus bentazon at 560 g/ha plus clethodim at 140 g/ha at 6 WAP. Soybeans were harvested at maturity, and seeds were analyzed for daidzein, daidzin, genistein, genistin, glycitin, glycitein, shikimate, glyphosate, and the glyphosate degradation product, aminomethylphosphonic acid (AMPA). There were no remarkable effects of any treatment on the contents of any of the biosynthetic compounds in soybean seed from either test site, indicating that early and later season applications of glyphosate have no effects on phytoestrogen levels in glyphosate-resistant soybeans. Glyphosate and AMPA residues were higher in seeds from treatment 3 than from the other two treatments in which glyphosate was used earlier. Intermediate levels were found in treatments 1 and 2. Low levels of glyphosate and AMPA were found in treatment 4 and a

  8. Postharvest Treatment with β-Aminobutyric Acid Induces Resistance Against Dry Rot Caused by Fusarium sulphureum in Potato Tuber

    Institute of Scientific and Technical Information of China (English)

    YIN Yan; LI Yong-cai; BI Yang; CHEN Song-jiang; LI Ying-chao; YUAN Li; WANG Yi; WANG Di

    2010-01-01

    The effectiveness of postharvest β-aminobutyric acid(BABA)treatment was studied for inducing resistance against dry rot caused by Fusarium sulphureum in tubers and slices of two potato cultivars(resistant cultivar Shepody and susceptible cultivar Xindaping).The results showed that BABA at 100 mmol L-1 significantly reduced lesion diameter in inoculated both tubers and slices.The chemical at 100 mmol L-1 showed an effective reduction in infection ability of F.sulphureum inoculated 48 and 72 h after treatment in slices of resistant cultivar,and 72 and 96 h in susceptible ones.BABA increased the activitives of peroxidase(POD),polyphenoloxidase(PPO)and phenylalanine ammonialyase(PAL),and accumulated the contents of lignin,flavonoids and phenolics in slices.The resistant cultivar had a stronger resistant response than the susceptible one.These findings suggest that the BABA treatment can induce the resistance in potato tubers,however,the inducing degree depends on the original level of resistance present in each cultivar.

  9. DL-β-aminobutyric acid-induced resistance in soybean against Aphis glycines Matsumura (Hemiptera: Aphididae.

    Directory of Open Access Journals (Sweden)

    Yunpeng Zhong

    Full Text Available Priming can improve plant innate capability to deal with the stresses caused by both biotic and abiotic factors. In this study, the effect of DL-β-amino-n-butyric acid (BABA against Aphis glycines Matsumura, the soybean aphid (SA was evaluated. We found that 25 mM BABA as a root drench had minimal adverse impact on plant growth and also efficiently protected soybean from SA infestation. In both choice and non-choice tests, SA number was significantly decreased to a low level in soybean seedlings drenched with 25 mM BABA compared to the control counterparts. BABA treatment resulted in a significant increase in the activities of several defense enzymes, such as phenylalanine ammonia-lyase (PAL, peroxidase (POX, polyphenol oxidase (PPO, chitinase (CHI, and β-1, 3-glucanase (GLU in soybean seedlings attacked by aphid. Meanwhile, the induction of 15 defense-related genes by aphid, such as AOS, CHS, MMP2, NPR1-1, NPR1-2, and PR genes, were significantly augmented in BABA-treated soybean seedlings. Our study suggest that BABA application is a promising way to enhance soybean resistance against SA.

  10. Effect of amino acid application on induced resistance against citrus canker disease in lime plants

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.

  11. Mycophenolic acid potently inhibits rotavirus infection with a high barrier to resistance development.

    Science.gov (United States)

    Yin, Yuebang; Wang, Yijin; Dang, Wen; Xu, Lei; Su, Junhong; Zhou, Xinying; Wang, Wenshi; Felczak, Krzysztof; van der Laan, Luc J W; Pankiewicz, Krzysztof W; van der Eijk, Annemiek A; Bijvelds, Marcel; Sprengers, Dave; de Jonge, Hugo; Koopmans, Marion P G; Metselaar, Herold J; Peppelenbosch, Maikel P; Pan, Qiuwei

    2016-09-01

    Rotavirus infection has emerged as an important cause of complications in organ transplantation recipients. Immunosuppressants used to prevent alloreactivity can also interfere with virus infection, but the direct effects of the specific type of immunosuppressants on rotavirus infection are still unclear. Here we profiled the effects of different immunosuppressants on rotavirus using a 2D culture model of Caco2 human intestinal cell line and a 3D model of human primary intestinal organoids inoculated with laboratory and patient-derived rotavirus strains. We found that the responsiveness of rotavirus to Cyclosporine A treatment was moderate and strictly regulated in an opposite direction by its cellular targets cyclophilin A and B. Treatment with mycophenolic acid (MPA) resulted in a 99% inhibition of viral RNA production at the clinically relevant concentration (10 μg/ml) in Caco2 cells. This effect was further confirmed in organoids. Importantly, continuous treatment with MPA for 30 passages did not attenuate its antiviral potency, indicating a high barrier to drug resistance development. Mechanistically, the antiviral effects of MPA act via inhibiting the IMPDH enzyme and resulting in guanosine nucleotide depletion. Thus for transplantation patients at risk for rotavirus infection, the choice of MPA as an immunosuppressive agent appears rational. PMID:27468950

  12. Production of resistant starch by extrusion cooking of acid-modified normal-maize starch.

    Science.gov (United States)

    Hasjim, Jovin; Jane, Jay-Lin

    2009-09-01

    The objective of this study was to utilize extrusion cooking and hydrothermal treatment to produce resistant starch (RS) as an economical alternative to a batch-cooking process. A hydrothermal treatment (110 degrees C, 3 d) of batch-cooked and extruded starch samples facilitated propagation of heat-stable starch crystallites and increased the RS contents from 2.1% to 7.7% up to 17.4% determined using AOAC Method 991.43 for total dietary fiber. When starch samples were batch cooked and hydrothermally treated at a moisture content below 70%, acid-modified normal-maize starch (AMMS) produced a greater RS content than did native normal-maize starch (NMS). This was attributed to the partially hydrolyzed, smaller molecules in the AMMS, which had greater mobility and freedom than the larger molecules in the NMS. The RS contents of the batch-cooked and extruded AMMS products after the hydrothermal treatment were similar. A freezing treatment of the AMMS samples at -20 degrees C prior to the hydrothermal treatment did not increase the RS content. The DSC thermograms and the X-ray diffractograms showed that retrograded amylose and crystalline starch-lipid complex, which had melting temperatures above 100 degrees C, accounted for the RS contents.

  13. Pseudomonas aeruginosa inducing rice resistance against Rhizoctonia solani: production of salicylic acid and peroxidases.

    Science.gov (United States)

    Saikia, R; Kumar, R; Arora, D K; Gogoi, D K; Azad, P

    2006-01-01

    Three isolates of Pseudomonas aeruginosa were used for seed treatment of rice; all showed plant growth promoting activity and induced systemic resistance in rice against Rhizoctonia solani G5 and increased seed yield. Production of salicylic acid (Sal) by P. aeruginosa both in vitro and in vivo was quantified with high performance liquid chromatography. All three isolates produced more Sal in King's B broth than in induced roots. Using a split root system, more Sal accumulated in root tissues of bacterized site than in distant roots on the opposite site of the root system after 1 d, but this difference decreased after 3 d. Sal concentration 0-200 g/L showed no inhibition of mycelial growth of R. solani in vitro, while at > or =300 g/L it inhibited it. P. aeruginosa-pretreated rice plants challenged inoculation with R. solani (as pathogen), an additional increase in the accumulation of peroxidase was observed. Three pathogenesis-related peroxidases in induced rice plants were detected; molar mass of these purified peroxidases was 28, 36 and 47 kDa. Purified peroxidase showed antifungal activity against phytopathogenic fungi R. solani, Pyricularia oryzae and Helminthosporium oryzae. PMID:17176755

  14. Induction of systemic resistance of benzothiadiazole and humic Acid in soybean plants against fusarium wilt disease.

    Science.gov (United States)

    Abdel-Monaim, Montaser Fawzy; Ismail, Mamdoh Ewis; Morsy, Kadry Mohamed

    2011-12-01

    The ability of benzothiadiazole (BTH) and/or humic acid (HA) used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Alone and in combination the inducers were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations (Minia and New Valley governorates). The tested treatments significantly reduced damping-off and wilt diseases and increased growth parameters, except the number of branches per plant and also increased seed yield. Application of BTH (0.25 g/L) + HA (4 g/L) was the most potent in this respect. Soybean seed soaking in BTH + HA produced the highest activities of the testes of oxidative enzymes followed by BTH in the four soybean cultivars. HA treatment resulted in the lowest increases of these oxidative enzymes. Similar results were obtained with total phenol but HA increased total phenol more than did BTH in all tested cultivars. PMID:22783118

  15. Characterization of an Arabidopsis-Phytophthora pathosystem: resistance requires a functional PAD2 gene and is independent of salicylic acid, ethylene and jasmonic acid signalling.

    Science.gov (United States)

    Roetschi, A; Si-Ammour, A; Belbahri, L; Mauch, F; Mauch-Mani, B

    2001-11-01

    Arabidopsis accessions were screened with isolates of Phytophthora porri originally isolated from other crucifer species. The described Arabidopsis-Phytophthora pathosystem shows the characteristics of a facultative biotrophic interaction similar to that seen in agronomically important diseases caused by Phytophthora species. In susceptible accessions, extensive colonization of the host tissue occurred and sexual and asexual spores were formed. In incompatible combinations, the plants reacted with a hypersensitive response (HR) and the formation of papillae at the sites of attempted penetration. Defence pathway mutants such as jar1 (jasmonic acid-insensitive), etr1 (ethylene receptor mutant) and ein2 (ethylene-insensitive) remained resistant towards P. porri. However, pad2, a mutant with reduced production of the phytoalexin camalexin, was hyper-susceptible. The accumulation of salicylic acid (SA) and PR1 protein was strongly reduced in pad2. Surprisingly, this lack of SA accumulation does not appear to be the cause of the hyper-susceptibility because interference with SA signalling in nahG plants or sid2 or npr1 mutants had only a minor effect on resistance. In addition, the functional SA analogue benzothiadiazol (BTH) did not induce resistance in susceptible plants including pad2. Similarly, the complete blockage of camalexin biosynthesis in pad3 did not cause susceptibility. Resistance of Arabidopsis against P. porri appears to depend on unknown defence mechanisms that are under the control of PAD2.

  16. Induction of Heat Resistance in Wheat Coleoptiles by 4-Hydroxybenzoic Acid: Connection with the Generation of Reactive Oxygen Species

    Directory of Open Access Journals (Sweden)

    Yastreb T.O.

    2012-08-01

    Full Text Available The effect of 4-hydroxybenzoic acid (4-HBA on resistance of coleoptiles of 4-day-old etiolated seedlings of wheat (Triticum aestivum L., cv. Elegiya to damaging heating (10 min at 43°C and possible dependence of this effect on changes in the activities of enzymes producing and scavenging reactive oxygen species (ROS were investigated. Treatment of coleoptiles with 10 μM 4-HBA resulted in enhancing of superoxide anion-radical generation and maintaining of hydrogen peroxide content there in. Increasing of the rate of ROS production was significantly suppressed by inhibitors of NADPH oxidase (α-naphthol and peroxidase (salicylhydroxamic acid. Under the influence of 4-HBA the activities of superoxide dismutase and apoplastic forms of peroxidase were increased. The activity of oxalate oxidase and catalase has not changed. Exogenous 4-HBA improved coleoptiles heat resistance and its effects were comparable with the influence of salicylic acid. Antioxidant agent BHT (butylhydroxytoluene, inhibitors of NADPH oxidase and peroxidase significantly reduced the increasing of wheat coleoptiles heat resistance, caused by 4-HBA action. It was concluded that 4-HBA influence on coleoptiles heat resistance is realized with the ROS mediation.

  17. Plants on constant alert: elevated levels of jasmonic acid and jasmonate-induced transcripts in caterpillar-resistant maize.

    Science.gov (United States)

    Shivaji, Renuka; Camas, Alberto; Ankala, Arunkanth; Engelberth, Jurgen; Tumlinson, James H; Williams, W Paul; Wilkinson, Jeff R; Luthe, Dawn Sywassink

    2010-02-01

    This study was conducted to determine if constitutive levels of jasmonic acid (JA) and other octadecanoid compounds were elevated prior to herbivory in a maize genotype with documented resistance to fall armyworm (Spodoptera frugiperda) and other lepidopteran pests. The resistant inbred Mp708 had approximately 3-fold higher levels of jasmonic acid (JA) prior to herbivore feeding than the susceptible inbred Tx601. Constitutive levels of cis-12-oxo-phytodienoic acid (OPDA) also were higher in Mp708 than Tx601. In addition, the constitutive expression of JA-inducible genes, including those in the JA biosynthetic pathway, was higher in Mp708 than Tx601. In response to herbivory, Mp708 generated comparatively higher levels of hydrogen peroxide, and had a greater abundance of NADPH oxidase transcripts before and after caterpillar feeding. Before herbivore feeding, low levels of transcripts encoding the maize insect resistance cysteine protease (Mir1-CP) and the Mir1-CP protein were detected consistently. Thus, Mp708 appears to have a portion of its defense pathway primed, which results in constitutive defenses and the ability to mount a stronger defense when caterpillars attack. Although the molecular mechanisms that regulate the constitutive accumulation of JA in Mp708 are unknown, it might account for its enhanced resistance to lepidopteran pests. This genotype could be valuable in studying the signaling pathways that maize uses to response to insect herbivores.

  18. Both the Jasmonic Acid and the Salicylic Acid Pathways Contribute to Resistance to the Biotrophic Clubroot Agent Plasmodiophora brassicae in Arabidopsis.

    Science.gov (United States)

    Lemarié, Séverine; Robert-Seilaniantz, Alexandre; Lariagon, Christine; Lemoine, Jocelyne; Marnet, Nathalie; Jubault, Mélanie; Manzanares-Dauleux, Maria J; Gravot, Antoine

    2015-11-01

    The role of salicylic acid (SA) and jasmonic acid (JA) signaling in resistance to root pathogens has been poorly documented. We assessed the contribution of SA and JA to basal and partial resistance of Arabidopsis to the biotrophic clubroot agent Plasmodiophora brassicae. SA and JA levels as well as the expression of the SA-responsive genes PR2 and PR5 and the JA-responsive genes ARGAH2 and THI2.1 were monitored in infected roots of the accessions Col-0 (susceptible) and Bur-0 (partially resistant). SA signaling was activated in Bur-0 but not in Col-0. The JA pathway was weakly activated in Bur-0 but was strongly induced in Col-0. The contribution of both pathways to clubroot resistance was then assessed using exogenous phytohormone application and mutants affected in SA or JA signaling. Exogenous SA treatment decreased clubroot symptoms in the two Arabidopsis accessions, whereas JA treatment reduced clubroot symptoms only in Col-0. The cpr5-2 mutant, in which SA responses are constitutively induced, was more resistant to clubroot than the corresponding wild type, and the JA signaling-deficient mutant jar1 was more susceptible. Finally, we showed that the JA-mediated induction of NATA1 drove N(δ)-acetylornithine biosynthesis in infected Col-0 roots. The 35S::NATA1 and nata1 lines displayed reduced or enhanced clubroot symptoms, respectively, thus suggesting that in Col-0 this pathway was involved in the JA-mediated basal clubroot resistance. Overall, our data support the idea that, depending on the Arabidopsis accession, both SA and JA signaling can play a role in partial inhibition of clubroot development in compatible interactions with P. brassicae.

  19. Berberine reverses free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM:To investigate the effects and molecular mechanisms of berberine on improving insulin resistance induced by free fatty acids (FFAs) in 3T3-LI adipocytes.METHODS:The model of insulin resistance in 3T3-L1 adipocytes was established by adding palmic acid (0.5 mmol/L) to the culture medium.Berberine treatment was performed at the same time.Glucose uptake rate was determined by the 2-deoxy-[3H]-Dglucose method.The levels of IkB kinase beta (IKKβ)Ser181 phosphorylation,insulin receptor substrate1(IRS-1) Ser307 phosphorylation,expression of IKKβ,IRS-1,nuclear transcription factor kappaB p65 (NF-κB p65),phosphatidylinositol-3-kinase p85(PI-3K p85) and glucose transporter 4 (GLUT4) proteins were detected by Western blotting.The distribution of NF-κB p65 proteins inside the adipocytes was observed through confocal laser scanning microscopy(CLSM).RESULTS:After the intervention of palmic acid for 24 h,the insulin-stimulated glucose transport in 3T3-L1 adipocytes was inhibited by 67%.Meanwhile,the expression of IRS-1 and PI-3K p85 protein was reduced,while the levels of IKKβ Ser181 and IRS-1 Ser307 phosphorylation,and nuclear translocation of NF-κB p65 protein were increased.However,the above indexes,which indicated the existence of insulin resistance,were reversed by berberine although the expression of GLUT4,IKKβ and total NF-κB p65 protein were not changed during this study.CONCLUSION:Insulin resistance induced by FFAs in 3T3-L1 adipocytes can be improved by berberine.Berberine reversed free-fatty-acid-induced insulin resistance in 3T3-L1 adipocytes through targeting IKKβ.

  20. Leptin receptor polymorphisms interact with polyunsaturated fatty acids to augment risk of insulin resistance and metabolic syndrome in adults.

    Science.gov (United States)

    Phillips, Catherine M; Goumidi, Louisa; Bertrais, Sandrine; Field, Martyn R; Ordovas, Jose M; Cupples, L Adrienne; Defoort, Catherine; Lovegrove, Julie A; Drevon, Christian A; Blaak, Ellen E; Gibney, Michael J; Kiec-Wilk, Beata; Karlstrom, Britta; Lopez-Miranda, Jose; McManus, Ross; Hercberg, Serge; Lairon, Denis; Planells, Richard; Roche, Helen M

    2010-02-01

    The leptin receptor (LEPR) is associated with insulin resistance, a key feature of metabolic syndrome (MetS). Gene-fatty acid interactions may affect MetS risk. The objective was to investigate the relationship among LEPR polymorphisms, insulin resistance, and MetS risk and whether plasma fatty acids, a biomarker of dietary fatty acids, modulate this. LEPR polymorphisms (rs10493380, rs1137100, rs1137101, rs12067936, rs1805096, rs2025805, rs3790419, rs3790433, rs6673324, and rs8179183), biochemical measurements, and plasma fatty acid profiles were determined in the LIPGENE-SU.VI.MAX study of MetS cases and matched controls (n = 1754). LEPR rs3790433 GG homozygotes had increased MetS risk compared with the minor A allele carriers [odds ratio (OR) = 1.65; 95% CI: 1.05-2.57; P = 0.028], which may be accounted for by their increased risk of elevated insulin concentrations (OR 2.40; 95% CI: 1.28-4.50; P = 0.006) and insulin resistance (OR = 2.15; 95% CI: 1.18-3.90; P = 0.012). Low (less than median) plasma (n-3) and high (n-6) PUFA status exacerbated the genetic risk conferred by GG homozygosity to hyperinsulinemia (OR 2.92-2.94) and insulin resistance (OR 3.40-3.47). Interestingly, these associations were abolished against a high (n-3) or low (n-6) PUFA background. Importantly, we replicated some of these findings in an independent cohort. Homozygosity for the LEPR rs3790433 G allele was associated with insulin resistance, which may predispose to increased MetS risk. Novel gene-nutrient interactions between LEPR rs3790433 and PUFA suggest that these genetic influences were more evident in individuals with low plasma (n-3) or high plasma (n-6) PUFA. PMID:20032477

  1. Ursolic acid attenuates temozolomide resistance in glioblastoma cells by downregulating O6-methylguanine-DNA methyltransferase (MGMT) expression

    Science.gov (United States)

    Zhu, Zhongling; Du, Shuangshuang; Ding, Fengxia; Guo, Shanshan; Ying, Guoguang; Yan, Zhao

    2016-01-01

    The DNA-alkylating agent temozolomide (TMZ) is an effective chemotherapeutic agent against malignant glioma, including glioblastoma multiforme (GBM). However, the clinical efficacy of TMZ is limited in many patients because of O6-methylguanine-DNA methyltransferase (MGMT)-driven resistance. Thus, new strategies to overcome TMZ resistance are urgently needed. Ursolic acid (UA) is a naturally derived pentacyclic triterpene acid that exerts broad anticancer effects, and shows capability to cross the blood-brain barrier. In this study, we evaluated the possible synergistic effect of TMZ and UA in resistant GBM cell lines. The results showed that UA prevented the proliferation of resistant GBM cells in a concentration-dependent manner. Compared with TMZ or UA treatment alone, the combination treatment of TMZ and UA synergistically enhanced cytotoxicity and senescence in TMZ-resistant GBM cells. This effect was correlated with the downregulation of MGMT. Moreover, experimental results with an in vivo mouse xenograft model showed that the combination treatment of UA and TMZ reduced tumor volumes by depleting MGMT. Therefore, UA as both a monotherapy and a resensitizer, might be a candidate agent for patients with refractory malignant gliomas. PMID:27508051

  2. Arsenic, Anaerobes, and Astrobiology

    Science.gov (United States)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  3. CO2 incorporation and 4-hydroxy-2-methylbenzoic acid formation during anaerobic metabolism of m-cresol by a methanogenic consortium

    International Nuclear Information System (INIS)

    The metabolism of m-cresol by methanogenic cultures enriched from domestic sewage sludge was investigated. In the initial studies, bromoethanesulfonic acid was used to inhibit methane production. This led to the accumulation of 4.0 ± 0.8 mol of acetate per mol of m-cresol metabolized. These results suggested that CO2 incorporation occurred because each molecule of m-cresol contained seven carbon atoms, whereas four molecules of acetate product contained a total of eight carbon atoms. To verify this, [14C]bicarbonate was added to bromoethanesulfonic acid-inhibited cultures, and those cultures yielded [14C]acetate. Of the label recovered as acetate, 89% was found in the carboxyl position. Similar cultures fed [methyl-14C]m-cresol yielded methyl-labeled acetate. A 14C-labeled transient intermediate was detected in cultures given either m-cresol and [14C]bicarbonate or bicarbonate and [methyl-14C]m-cresol. The intermediate was identified as 4-hydroxy-2-methylbenzoic acid. In addition, another metabolite was detected and identified as 2-methylbenzoic acid. This compound appeared to be produced only sporadically, and it accumulated in the medium, suggested that the dehydroxylation of 4-hydroxy-2-methylbenzoic acid led to an apparent dead-end product

  4. Combined Anaerobic-Aerobic Bacterial Degradation of Dyes

    OpenAIRE

    R. Wilfred Sugumar; Sandhya Sadanandan

    2010-01-01

    Wastewaters from the dye baths of a non-formal textile-dyeing unit containing C.I. Acid Orange 7 and C.I. Reactive Red 2 were subjected to degradation in a sequential anaerobic-aerobic treatment process based on mixed culture of bacteria. The technical samples of the dyestuffs and the dye bath wastes were treated in an anaerobic reactor, using an adapted mixed culture of anaerobic microorganisms. The dyestuffs were biotransformed into colourless substituted amine metabolites in the reactor. T...

  5. Failure of combination therapy for Staphylococcus aureus bone infection: a case of in vivo selection with resistance to rifampicin and fusidic acid.

    Science.gov (United States)

    Aubin, Guillaume G; Bémer, Pascale; Guillouzouic, Aurélie; Launay, Elise; Geffroy, Loïc; Touchais, Sophie; Corvec, Stéphane

    2016-09-01

    Staphylococcus aureus is one of the main etiologies of bone and device-related infections. Treatment of these orthopedic infections combines mostly rifampicin with other antibiotics. The recurrence or failure rate after fusidic acid/rifampicin treatment remains low (Staphylococcus aureus bone infection with in vivo selection of rifampicin and fusidic acid resistance. We also report a new mutation in fusA gene involved in fusidic acid resistance. PMID:27194514

  6. Acid-resistance performance of reactive powder concrete%活性粉末混凝土的耐酸性

    Institute of Scientific and Technical Information of China (English)

    何峰; 黄政宇; 易伟建

    2011-01-01

    为了考察活性粉末混凝土在严酷环境下的耐酸性能,试验研究了硫酸溶液和醋酸溶液对活性粉末混凝土强度的影响,并比较研究了硫酸溶液对普通水泥基材料和高强水泥基材料的影响.70d浸泡龄期的试验结果表明:在浸泡早期,3种水泥基材料的耐硫酸性能差别不明显,随着暴露时间的延长,活性粉末混凝土比普通水泥基材料和高强水泥基材料呈现出较好的耐硫酸性能;弱离解的醋酸溶液对活性粉末混凝土的侵蚀作用比强离解的硫酸溶液更强.前者与3种水泥基材料的孔隙率、孔隙结构、抗渗性及抗裂性等因素有关,后者则与醋酸溶液的强扩散性有关.%To investigate acid-resistance performance of reactive powder concrete (RPC) in the harsh environment,the effects of sulfuric acid and acetic acid solutions on the strength of RPC were investigated by test. At the same time, the effects of sulfuric acid solution on the strength of normal cement-based material and high strength cementbased material were studied for reference purposes. The test data of 70 days' exposure ages show that the difference of sulfuric acid-resistance performance of three cement-based materials is not clear in the early ages, RPC has the best sulfuric acid-resistance performance compared tonormal cement-based material and high strength cement-based material with the extended exposure ages, and the aggressive effect of weak dissociation of acetic acid on RPC is greater than that of strong dissociation of sulfuric acid. The former is affected by porosity, pore structure, impermeability and crack resistance of three cement - based materials. The latter is connected with strong diffusivity of acetic acid.

  7. Old Drugs To Treat Resistant Bugs: Methicillin-Resistant Staphylococcus aureus Isolates with mecC Are Susceptible to a Combination of Penicillin and Clavulanic Acid.

    Science.gov (United States)

    Ba, Xiaoliang; Harrison, Ewan M; Lovering, Andrew L; Gleadall, Nicholas; Zadoks, Ruth; Parkhill, Julian; Peacock, Sharon J; Holden, Matthew T G; Paterson, Gavin K; Holmes, Mark A

    2015-12-01

    β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections. PMID:26392513

  8. Old Drugs To Treat Resistant Bugs: Methicillin-Resistant Staphylococcus aureus Isolates with mecC Are Susceptible to a Combination of Penicillin and Clavulanic Acid.

    Science.gov (United States)

    Ba, Xiaoliang; Harrison, Ewan M; Lovering, Andrew L; Gleadall, Nicholas; Zadoks, Ruth; Parkhill, Julian; Peacock, Sharon J; Holden, Matthew T G; Paterson, Gavin K; Holmes, Mark A

    2015-12-01

    β-Lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is mediated by the expression of an alternative penicillin-binding protein 2a (PBP2a) (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA, known as mecC, was identified in MRSA isolates from both humans and animals. In this study, we demonstrate that mecC-encoded PBP2c does not mediate resistance to penicillin. Rather, broad-spectrum β-lactam resistance in MRSA strains carrying mecC (mecC-MRSA strains) is mediated by a combination of both PBP2c and the distinct β-lactamase encoded by the blaZ gene of strain LGA251 (blaZLGA251), which is part of mecC-encoding staphylococcal cassette chromosome mec (SCCmec) type XI. We further demonstrate that mecC-MRSA strains are susceptible to the combination of penicillin and the β-lactam inhibitor clavulanic acid in vitro and that the same combination is effective in vivo for the treatment of experimental mecC-MRSA infection in wax moth larvae. Thus, we demonstrate how the distinct biological differences between mecA- and mecC-encoded PBP2a and PBP2c have the potential to be exploited as a novel approach for the treatment of mecC-MRSA infections.

  9. Mutation of G234 amino acid residue in candida albicans drug-resistance-related protein Rta2p is associated with fluconazole resistance and dihydrosphingosine transport.

    Science.gov (United States)

    Zhang, Shi-Qun; Miao, Qi; Li, Li-Ping; Zhang, Lu-Lu; Yan, Lan; Jia, Yu; Cao, Yong-Bing; Jiang, Yuan-Ying

    2015-01-01

    Widespread and repeated use of azoles has led to the rapid development of drug resistance in Candida albicans. Our previous study found Rta2p, a membrane protein with 7 transmembrane domains, was involved in calcineurin-mediated azole resistance and sphingoid long-chain base release in C. albicans. Conserved amino acids in the transmembrane domain of Rta2p were subjected to site-directed mutagenesis. The sensitivity of C. albicans to fluconazole in vitro was examined by minimum inhibitory concentration and killing assay, and the therapeutic efficacy of fluconazole in vivo was performed by systemic mice candidiasis model. Furthermore, dihydrosphingosine transport activity was detected by NBD labeled D-erythro-dihydrosphingosine uptake and release assay, and the sensitivity to sphingolipid biosynthesis inhibitors. We successfully constructed 14 mutant strains of Rta2p, screened them by minimum inhibitory concentration and found Ca(2+) did not completely induce fluconazole resistance with G158E and G234S mutations. Furthermore, we confirmed that G234S mutant enhanced the therapeutic efficacy of fluconazole against systemic candidiasis and significantly increased the accumulation of dihydrosphingosine by decreasing its release. However, G158E mutant didn't affect drug therapeutic efficacy in vivo and dihydrosphingosine transport in C. albicans. G234 of Rta2p in C. albicans is crucial in calcineurin-mediated fluconazole resistance and dihydrosphingosine transport. PMID:26220356

  10. Fermentation and Anaerobic Respiration by Rhodospirillum rubrum and Rhodopseudomonas capsulata

    OpenAIRE

    Schultz, J E; Weaver, P. F.

    1982-01-01

    Rhodospirillum rubrum and Rhodopseudomonas capsulata were able to grow anaerobically in the dark either by a strict mixed-acid fermentation of sugars or, in the presence of an appropriate electron acceptor, by an energy-linked anaerobic respiration. Both species fermented fructose without the addition of accessory oxidants, but required the initial presence of bicarbonate before fermentative growth could begin. Major products of R. rubrum fermentation were succinate, acetate, propionate, form...

  11. Pretreatment of citrus peel press liquor before anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Lane, A.G.

    1983-02-01

    Centrifugation and aeration were unsuitable pretreatments before anaerobic digestion of press liquors from citrus peel. Non-aerated fermentation without pH control resulted in conversion of sugars to acids and ethyl alcohol with reduction in pH to 2.8 - 3.5. These acidified liquors had a pleasant smell, were stable on storage and were satisfactory feedstock for anaerobic digestion. (Refs. 7).

  12. Anaerobic bacteria in otitis media.

    Science.gov (United States)

    Fulghum, R S; Daniel, H J; Yarborough, J G

    1977-01-01

    Anaerobic bacteria, Peptostrepotococcus intermedius and Propionibacterium acnes, were found in mixed culture specimens from four to ten tested cases of chronic secretory otitis media. These anaerobic bacteria were in a mixed infection flora with aerobic bacteria most often Staphylococcus epidermidis and Cornybacterium sp. which do not fit any established species. The findings of anaerobic bacteria in otitis media is consistent with the sporadic report of the involvement of anaerobic bacteria in otitis media in the literature since 1898.

  13. Anaerobic metabolism in the N-limited green alga Selenastrum minutum. 3. Alanine is the product of anaerobic ammonium assimilation

    International Nuclear Information System (INIS)

    The authors have determined the flow of 15N into free amino acids of the N-limited green alga Selenastrum minutum (Naeg.) Collins after addition of 15NH4+ to aerobic or anaerobic cells. Under aerobic conditions, only a small proportion of the N assimilated was retained in the free amino acid pool. However, under anaerobic conditions almost all assimilated NH4+ accumulates in alanine. This is a unique feature of anaerobic NH4+ assimilation. The pathway of carbon flow to alanine results in the production of ATP and reductant which matches exactly the requirements of NH4+ assimilation. Alanine synthesis is therefore an excellent strategy to maintain energy and redox balance during anaerobic NH4+ assimilation

  14. Salmonella isolated from ready-to-eat pasteurized liquid egg products: Thermal resistance, biochemical profile, and fatty acid analysis.

    Science.gov (United States)

    Gurtler, Joshua B; Hinton, Arthur; Bailey, Rebecca B; Cray, William C; Meinersmann, Richard J; Ball, Takiyah A; Jin, Tony Z

    2015-08-01

    The Egg Products Inspection Act of 1970 requires that egg products in the U.S. must be pasteurized prior to release into commerce. The USDA Food Safety and Inspection Service (FSIS) is responsible for regulating egg products. Salmonellae are infrequently isolated from pasteurized egg products by food manufacturers or the FSIS and may be present as a result of either pasteurization-resistant bacteria or post-processing contamination. In this study, seventeen strains of Salmonella isolated from pasteurized egg products and three heat-resistant control strains were compared for the following attributes: thermal resistance in liquid whole egg (LWE) at 60 °C, enzymatic profiles, and serotyping and phage typing, antibiotic susceptibility, fatty acid analysis and strain morphological variation evaluated by scanning electron microscopy. Isolates were serotyped as Heidelberg (4 isolates), Widemarsh, Mbandaka, Cerro, Thompson, 4,12:i:-, and Enteritidis (8 isolates). All 20 isolates were sensitive to all 14 antibiotics tested for. The D60 values in LWE ranged from 0.34 to 0.58 min. All 20 strains were recovered from LWE inoculated with 8.5 logCFU/mL of Salmonella and pasteurized at 60 °C for 3.5 min; however, some isolates were not recovered from pasteurized LWE that had been inoculated with only 4.5 logCFU/mL Salmonella and treated at 60 °C for 3.5 min. Although some strains exhibited atypical enzymatic activity (e.g., reduction of adonitol, hydrolysis of proline nitroanilide or p-n-p-beta-glucuronide, and nonreduction of melibiose), differences in biochemical reactions could not be correlated with differences in thermal resistance. Furthermore, fatty acid analysis revealed that differences insaturate/unsaturated profiles may be correlated with differences in heat resistance, in two instances. One heat resistant strain (#13, Enteritidis) had the statistically lowest unsaturated/saturate ratio at 39%. However, one heat sensitive strain (#3, serovar 4,12:i:-) had the

  15. Syntrophic interactions improve power production in formic acid fed MFCs operated with set anode potentials or fixed resistances

    KAUST Repository

    Sun, Dan

    2011-10-24

    Formic acid is a highly energetic electron donor but it has previously resulted in low power densities in microbial fuel cells (MFCs). Three different set anode potentials (-0.30, -0.15, and +0.15V; vs. a standard hydrogen electrode, SHE) were used to evaluate syntrophic interactions in bacterial communities for formic acid degradation relative to a non-controlled, high resistance system (1,000Ω external resistance). No current was generated at -0.30V, suggesting a lack of direct formic acid oxidation (standard reduction potential: -0.40V). More positive potentials that allowed for acetic acid utilization all produced current, with the best performance at -0.15V. The anode community in the -0.15V reactor, based on 16S rDNA clone libraries, was 58% Geobacter sulfurreducens and 17% Acetobacterium, with lower proportions of these genera found in the other two MFCs. Acetic acid was detected in all MFCs suggesting that current generation by G. sulfurreducens was dependent on acetic acid production by Acetobacterium. When all MFCs were subsequently operated at an external resistance for maximum power production (100Ω for MFCs originally set at -0.15 and +0.15V; 150Ω for the control), they produced similar power densities and exhibited the same midpoint potential of -0.15V in first derivative cyclic voltammetry scans. All of the mixed communities converged to similar proportions of the two predominant genera (ca. 52% G. sulfurreducens and 22% Acetobacterium). These results show that syntrophic interactions can be enhanced through setting certain anode potentials, and that long-term performance produces stable and convergent communities. © 2011 Wiley Periodicals, Inc.

  16. The effect of dilution and L-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Azbar, Nuri; Cetinkaya Dokgoz, F.Tuba [Ege University, Faculty of Engineering, Bioengineering Department, 35100 Izmir (Turkey)

    2010-05-15

    In this study, H{sub 2} was produced from cheese whey wastewater in a two-stage biological process: i) first stage; thermophilic dark fermentation ii) second stage; the photo fermentation using Rhodopseudomonas palustris strain DSM 127 (R. palustris). The effect of both dilution and addition of L-malic acid on the hydrogen production was investigated. Among the dilution rates used, 1/5 dilution ratio was found to produce the best hydrogen production (349 ml H{sub 2}/g COD{sub fed}). On the other hand, It was seen that the mixing the effluent with L-malic acid at increasing ratios had further positive effect and improved the hydrogen production significantly. It was concluded that dilution of the feeding helps to reduce the nitrogen content and the volatile fatty acid content that might be otherwise harmful to the photo-heterotrophic organisms. Overall hydrogen production yield (for dark + photo fermentation) was found to vary 2 and 10 mol H{sub 2}/mol lactose. Second conclusion is that cheese whey effluent should be mixed with a co-substrate containing L-malic acid such as apple juice processing effluents before fed into the photo fermentation reactor. (author)

  17. Influence of salicylic and succinic acids on antioxidant enzymes activity, heat resistance and productivity of Panicum miliaceum L.

    Directory of Open Access Journals (Sweden)

    Miroshnichenko N.N.

    2011-05-01

    Full Text Available The influence of treatment of millet (Panicum miliaceum L. seeds with the solutions of salicylic and succinic acids on the heat resistance of plantlets and activity of antioxidant enzymes – superoxide dismutase (SOD, catalase and peroxidase – in them have been investigated. In the micro-field experiment the influence of these acids on the millet yield was estimated. The action of salicylic (10 μM and succinic (1 mM acids caused the increase of plantlets resistance to the damaging heating that expressed in the rise of relative quantity of survived plantlets in 5 days after heating at the temperature of 47°С and in the reduced content of lipid peroxidation product malonic dialdehyde during the poststress period. The increase of activity of SOD, catalase and peroxidase took place in millet plantlets under the influence of salicylic and succinic acids. The increase of productivity of millet grain under the action of salicylic and succinic acids on 13,3-52,0 and 6,4-38,8% respectively depending on weather conditions in the field experiments was noted.

  18. NanR, a Transcriptional Regulator That Binds to the Promoters of Genes Involved in Sialic Acid Metabolism in the Anaerobic Pathogen Clostridium perfringens.

    Directory of Open Access Journals (Sweden)

    Blair Therit

    Full Text Available Among many other virulence factors, Clostridium perfringens produces three sialidases NanH, NanI and NanJ. NanH lacks a secretion signal peptide and is predicted to be an intracellular enzyme, while NanI and NanJ are secreted. Previously, we had identified part of an operon encoding NanE (epimerase and NanA (sialic acid lyase enzymes. Further analysis of the entire operon suggests that it encodes a complete pathway for the transport and metabolism of sialic acid along with a putative transcriptional regulator, NanR. The addition of 30 mM N-acetyl neuraminic acid (Neu5Ac to a semi-defined medium significantly enhanced the growth yield of strain 13, suggesting that Neu5Ac can be used as a nutrient. C. perfringens strain 13 lacks a nanH gene, but has NanI- and NanJ-encoding genes. Analysis of nanI, nanJ, and nanInanJ mutants constructed by homologous recombination revealed that the expression of the major sialidase, NanI, was induced by the addition of Neu5Ac to the medium, and that in separate experiments, the same was true of a nanI-gusA transcriptional fusion. For the nanI and nanJ genes, primer extension identified three and two putative transcription start sites, respectively. Gel mobility shift assays using purified NanR and DNA from the promoter regions of the nanI and nanE genes showed high affinity, specific binding by NanR. We propose that NanR is a global regulator of sialic acid-associated genes and that it responds, in a positive feedback loop, to the concentration of sialic acid in the cell.

  19. Comparison of local and systemic induction of acquired disease resistance in cucumber plants treated with benzothiadiazoles or salicylic acid.

    Science.gov (United States)

    Narusaka, Y; Narusaka, M; Horio, T; Ishii, H

    1999-04-01

    The accumulation of chitinase and its involvement in systemic acquired disease resistance was analyzed using acibenzolar-S-methyl and salicylic acid (SA). Resistance against scab (pathogen: Cladosporium cucumerinum) and the accumulation of chitinase were rapidly induced in cucumber plants after treatment with acibenzolar-S-methyl. In contrast, SA protected the plants from C. cucumerinum and the accumulation of chitinase was induced only on the treated leaves. The accumulation of chitinase in response to inoculation with the pathogen was induced more rapidly in cucumber plants previously treated with acibenzolar-S-methyl than in plants pretreated with SA or water. Thus, it appears that a prospective signal(s), that induces systemic resistance, can be transferred from leaves treated with acibenzolar-S-methyl to the untreated upper and lower leaves where systemic resistance is elicited. In contrast, exogenously applied SA is not likely to function as a mobile, systemic resistance-inducing signal, because SA only induces localized acquired resistance. PMID:10394634

  20. Novel gyrA point mutation in a strain of Escherichia coli resistant to fluoroquinolones but not to nalidixic acid.

    OpenAIRE

    Cambau, E.; Bordon, F; Collatz, E; Gutmann, L

    1993-01-01

    We have previously described a clinical isolate of Escherichia coli (Q2) that is highly resistant to fluoroquinolones (MIC of ciprofloxacin, 16 micrograms/ml) but susceptible to nalidixic acid (MIC of nalidixic acid, 4 micrograms/ml) (N. Moniot-Ville, J. Guibert, N. Moreau, J.F. Acar, E. Collatz, and L. Gutmann, Antimicrob. Agents Chemother. 35:519-523, 1991). Transformation of strain Q2 with a plasmid carrying the wild-type gyrA gene from E. coli K-12(pAFF801) resulted in a 32-fold decrease ...

  1. Anaerobic microbial LCFA degradation in bioreactors

    OpenAIRE

    Sousa, D.Z.; Pereira, M.A.; Alves, J.I.; Smidt, Hauke; Stams, A.J.M.; Alves, M. M.

    2008-01-01

    This paper reviews recent results obtained on long-chain fatty acids (LCFA) anaerobic degradation. Two LCFA were used as model substrates: oleate, a mono-unsaturated LCFA, and palmitate, a saturated LCFA, both abundant in LCFA-rich wastewaters. 16S rRNA gene analysis of sludge samples submitted to continuous oleate- and palmitate-feeding followed by batch degradation of the accumulated LCFA demonstrated that bacterial communities were dominated by members of the Clostridiaceae and Sy...

  2. Optimization of the tartrate-resistant acid phosphatase detection by histochemical method

    Science.gov (United States)

    Galvão, M.J.; Santos, A. R.; Ribeiro, M.D.; Ferreira, A.; Nolasco, F.

    2011-01-01

    According to the new kidney disease improving global outcomes (KDIGO) guidelines, the term of renal osteodystrophy, should be used exclusively in reference to the invasive diagnosis of bone abnormalities. Due to the low sensitivity and specificity of biochemical serum markers of bone remodelling, the performance of bone biopsies is highly stimulated in dialysis patients and after kidney transplantation. The tartrate-resistant acid phosphatase (TRACP) is an iso-enzyme of the group of acid phosphatases, which is highly expressed by activated osteoclasts and macrophages. TRACP in osteoclasts is in intracytoplasmic vesicles that transport the products of bone matrix degradation. Being present in activated osteoclasts, the identification of this enzyme by histochemistry in undecalcified bone biopsies is an excellent method to quantify the resorption of bone. Since it is an enzymatic histochemical method for a thermolabile enzyme, the temperature at which it is performed is particularly relevant. This study aimed to determine the optimal temperature for identification of TRACP in activated osteoclasts in undecalcified bone biopsies embedded in methylmethacrylate. We selected 10 cases of undecalcified bone biopsies from hemodialysis patients with the diagnosis of secondary hyperparathyroidism. Sections of 5 µm were stained to identify TRACP at different incubation temperatures (37°, 45°, 60°, 70° and 80°C) for 30 minutes. Activated osteoclasts stained red and trabecular bone (mineralized bone) was contrasted with toluidine blue. This approach also increased the visibility of the trabecular bone resorption areas (Howship lacunae). Unlike what is suggested in the literature and in several international protocols, we found that the best results were obtained with temperatures between 60°C and 70°C. For technical reasons and according to the results of the present study, we recommended that, for an incubation time of 30 min, the reaction should be carried out at 60

  3. Isolation of a thermostable acid phytase from Aspergillus niger UFV-1 with strong proteolysis resistance.

    Science.gov (United States)

    Monteiro, Paulo S; Guimarães, Valéria M; de Melo, Ricardo R; de Rezende, Sebastião T

    2015-03-01

    An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), indicating that it may be a dimer. It presented an optimum temperature of 60 °C and optimum pH of 2.0. The K M for sodium phytate hydrolysis was 30.9 mM, while the k cat and k cat / K M were 1.46 ×10 (5) s (-1) and 4.7 × 10 (6) s (-1) .M (-1) , respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg (2+) , Cd (2+) , K (+) and Ca (2+) , and it was drastically inhibited by F (-) . The enzyme displayed high thermostability, retaining more than 90% activity at 60 °C during 120 h and displayed a t 1/2 of 94.5 h and 6.2 h at 70 °C and 80 °C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 μmol phosphate/mL after 2.5 h of treatment. PMID:26221114

  4. Isolation of a thermostable acid phytase from Aspergillus niger UFV-1 with strong proteolysis resistance

    Directory of Open Access Journals (Sweden)

    Paulo S. Monteiro

    2015-03-01

    Full Text Available An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE, indicating that it may be a dimer. It presented an optimum temperature of 60 °C and optimum pH of 2.0. The KM for sodium phytate hydrolysis was 30.9 mM, while the kcat and kcat/KM were 1.46 ×105 s−1 and 4.7 × 106s−1.M−1, respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg2+, Cd2+, K+ and Ca2+, and it was drastically inhibited by F−. The enzyme displayed high thermostability, retaining more than 90% activity at 60 °C during 120 h and displayed a t1/2 of 94.5 h and 6.2 h at 70 °C and 80 °C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 μmol phosphate/mL after 2.5 h of treatment.

  5. Molecular level understanding of resistance to nalidixic acid in Salmonella enteric serovar typhimurium associates with the S83F sequence type.

    Science.gov (United States)

    Preethi, B; Ramanathan, K

    2016-01-01

    Nalidixic acid is an antibiotic drug used for treatment of Salmonellosis, a gastrointestinal infection. DNA gyrase subunit A (GyrA) of Salmonella typhimurium is the drug target for nalidixic acid. Resistance of GyrA to nalidixic acid, because of a point mutation in S. typhimurium, was recently reported. Substitution of Phe in place of Ser at locus 83 in GyrA of S. typhimurium has been experimentally associated with nalidixic acid resistance. Despite recent efforts, the mechanism of this resistance is not well understood. In this investigation we used computational techniques to address this shortcoming. Our results showed that contact with residue Arg 91 is certainly important for efficient binding of nalidixic acid to the target protein, and that mutation of this residue results in 180° rotation of the antibiotic in its binding pocket, around its own long axis. It is hoped these findings may enable development of new antibiotics against resistant forms of Salmonella. PMID:26329667

  6. Induction of Systematic Resistance in Soybean Plants against Fusarium Wilt Disease by Seed Treatment with Benzothiadiazole and Humic Acid

    OpenAIRE

    Montaser Fawzy ABDEL-MONAIM; Mamdoh Ewis ISMAIL; Morsy, Kadry Mohamed

    2011-01-01

    The ability of benzothiadiazole (BTH), humic acid (HA) and their combination when used as seed soaking to induce systemic resistance against a pathogenic strain of Fusarium oxysporum was examined in four soybean cultivars under greenhouse conditions. Both inducers and their combination were able to protect soybean plants against damping-off and wilt diseases compared with check treatment. These results were confirmed under field conditions in two different locations i. e Minia and New Valley ...

  7. Correlations between the contents of phytic acid and inorganic phosphorous and downy mildew resistance of corn inbred lines

    OpenAIRE

    Pantipa Na Chiangmai*; Phrutiya Nilprapruck; Warapon Bunkoed; Phakatip Yodmingkhwan; Chokechai Aekatasanawan; Mana Kanjanamaneesathian

    2015-01-01

    Seeds of corn inbred lines collected at the National Corn and Sorghum Research Center (NCSRC), Kasetsart University, were analyzed to determine the contents of phytic acid (PA) and inorganic phosphorous (InP). These 28 and 29 inbred lines were cultivated at the NCSRC (in the 2008 late rainy season and 2009 early rainy season) to evaluate their resistance to corn downy mildew caused by Peronosclerospora sorghi. Results showed that the values of the PA, InP contents and downy mildew...

  8. Tartrate resistant acid phosphatase 5a : a potential regulator of adipocyte cell number and differentiation in white adipose tissue

    OpenAIRE

    Patlaka, Christina

    2015-01-01

    Tartrate- resistant acid phosphatase (TRAP) exists in two isoforms, TRAP 5a which is monomeric and TRAP 5b which is a dimer generated by proteolytic cleavage of TRAP 5a, that exhibit different functions and localizations. TRAP 5a is expressed by adipose tissue macrophages and secreted into the extracellular environment and has been shown to lead to hyperplastic insulin- sensitive obesity when over-expressed in mice. In bone, TRAP is suggested to interact with the heparan sulfat...

  9. Anaerobic biotransformation of estrogens

    Energy Technology Data Exchange (ETDEWEB)

    Czajka, Cynthia P. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Londry, Kathleen L. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)]. E-mail: londryk@cc.umanitoba.ca

    2006-08-31

    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-{alpha}-ethynylestradiol (EE2) and 17-{beta}-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 {mu}g L{sup -1} day{sup -1}), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-{alpha}-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-{alpha}-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments.

  10. Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Ahring, Birgitte Kiær

    2007-01-01

    Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work, the therm......Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work...... fermented yielding ethanol of 0.39–0.42 g/g-sugars consumed. Xylose was nearly completely utilized (89–98%) for PCS up to 10% TS, whereas at 15% TS, xylose conversion was lowered to 67%. The reactor was operated continuously for 135 days, and no contamination was seen without the use of any agent...

  11. Amino acid substitution in Cryptococcus neoformans lanosterol 14-α-demethylase involved in fluconazole resistance in clinical isolates.

    Science.gov (United States)

    Bosco-Borgeat, María E; Mazza, Mariana; Taverna, Constanza G; Córdoba, Susana; Murisengo, Omar A; Vivot, Walter; Davel, Graciela

    2016-01-01

    The molecular basis of fluconazole resistance in Cryptococcus neoformans has been poorly studied. A common azole resistance mechanism in Candida species is the acquisition of point mutations in the ERG11 gene encoding the enzyme lanosterol 14-α-demethylase, target of the azole class of drugs. In C. neoformans only two mutations were described in this gene. In order to evaluate other mutations that could be implicated in fluconazole resistance in C. neoformans we studied the genomic sequence of the ERG11 gene in 11 clinical isolates with minimal inhibitory concentration (MIC) values to fluconazole of ≥16μg/ml. The sequencing revealed the G1855A mutation in 3 isolates, resulting in the enzyme amino acid substitution G484S. These strains were isolated from two fluconazole-treated patients. This mutation would not intervene in the susceptibility to itraconazole and voriconazole. PMID:27311753

  12. Corrosion resistance of flaky aluminum pigment coated with cerium oxides/hydroxides in chloride and acidic electrolytes

    Science.gov (United States)

    Niroumandrad, S.; Rostami, M.; Ramezanzadeh, B.

    2015-12-01

    The objective of this study was to enhance the corrosion resistance of lamellar aluminum pigment through surface treatment by cerium oxides/hydroxides. The surface composition of the pigments was studied by energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the pigment was evaluated by conventional hydrogen evolution measurements in acidic solution and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl solution. Results showed that the Ce-rich coating composed of Ce2O3 and CeO2 was precipitated on the pigment surface after immersion in the cerium solution. The corrosion resistance of pigment was significantly enhanced after modification with cerium layer.

  13. Esters of pyrazinoic acid are active against pyrazinamide-resistant strains of Mycobacterium tuberculosis and other naturally resistant mycobacteria in vitro and ex vivo within macrophages.

    KAUST Repository

    Pires, David

    2015-10-05

    Pyrazinamide (PZA) is active against major Mycobacterium tuberculosis species (M. tuberculosis, M. africanum, and M. microti), but not against M. bovis and M. avium. The latter two are mycobacteria species involved in human and cattle tuberculosis and in HIV co-infections, respectively. PZA is a first-line agent for the treatment of human tuberculosis and requires activation by a mycobacterial pyrazinamidase to form the active metabolite pyrazinoic acid (POA). As a result of this mechanism, resistance to PZA as often found in tuberculosis patients is caused by point mutations in pyrazinamidase. In previous work, we have shown that POA esters and amides synthesized in our laboratory were stable in plasma. Although the amides did not present significant activity, the esters were active against sensitive mycobacteria at concentrations 5-to-10 fold lower than those of PZA. Here, we report that these POA derivatives possess antibacterial efficacy in vitro and ex vivo against several species and strains of Mycobacterium with natural or acquired resistance to PZA, including M. bovis and M. avium. Our results indicate that the resistance was probably overcome by cleavage of the prodrugs into POA and a long-chain alcohol. Although it is not possible to rule out that the esters may have intrinsic activity per se, we bring evidence here that long-chain fatty alcohols possess a significant anti-mycobacterial effect against PZA-resistant species and strains and are not mere inactive promoieties. These findings may lead to candidate dual-drugs having enhanced activity against both PZA-susceptible and PZA-resistant isolates and being suitable for clinical development.

  14. Genetic modification of alternative respiration in Nicotiana benthamiana affects basal and salicylic acid-induced resistance to potato virus X

    Directory of Open Access Journals (Sweden)

    Verchot-Lubicz Jeanmarie

    2011-02-01

    Full Text Available Abstract Background Salicylic acid (SA regulates multiple anti-viral mechanisms, including mechanism(s that may be negatively regulated by the mitochondrial enzyme, alternative oxidase (AOX, the sole component of the alternative respiratory pathway. However, studies of this mechanism can be confounded by SA-mediated induction of RNA-dependent RNA polymerase 1, a component of the antiviral RNA silencing pathway. We made transgenic Nicotiana benthamiana plants in which alternative respiratory pathway capacity was either increased by constitutive expression of AOX, or decreased by expression of a dominant-negative mutant protein (AOX-E. N. benthamiana was used because it is a natural mutant that does not express a functional RNA-dependent RNA polymerase 1. Results Antimycin A (an alternative respiratory pathway inducer and also an inducer of resistance to viruses and SA triggered resistance to tobacco mosaic virus (TMV. Resistance to TMV induced by antimycin A, but not by SA, was inhibited in Aox transgenic plants while SA-induced resistance to this virus appeared to be stronger in Aox-E transgenic plants. These effects, which were limited to directly inoculated leaves, were not affected by the presence or absence of a transgene constitutively expressing a functional RNA-dependent RNA polymerase (MtRDR1. Unexpectedly, Aox-transgenic plants infected with potato virus X (PVX showed markedly increased susceptibility to systemic disease induction and virus accumulation in inoculated and systemically infected leaves. SA-induced resistance to PVX was compromised in Aox-transgenic plants but plants expressing AOX-E exhibited enhanced SA-induced resistance to this virus. Conclusions We conclude that AOX-regulated mechanisms not only play a role in SA-induced resistance but also make an important contribution to basal resistance against certain viruses such as PVX.

  15. Diversity of Anaerobic Microorganisms Involved in Long-Chain Fatty Acid Degradation in Methanogenic Sludges as Revealed by RNA-Based Stable Isotope Probing▿

    OpenAIRE

    Hatamoto, Masashi; IMACHI, HIROYUKI; Yashiro, Yuto; Ohashi, Akiyoshi; Harada, Hideki

    2007-01-01

    Long-chain fatty acid (LCFA) degradation is a key step in methanogenic treatment of wastes/wastewaters containing high concentrations of lipids. However, despite the importance of LCFA-degrading bacteria, their natural diversity is little explored due to the limited availability of isolate information and the lack of appropriate molecular markers. We therefore investigated these microbes by using RNA-based stable isotope probing. We incubated four methanogenic sludges (mesophilic sludges MP a...

  16. Evaluation of spectrophotometric and HPLC methods for shikimic acid determination in plants: models in glyphosate-resistant and -susceptible crops.

    Science.gov (United States)

    Zelaya, Ian A; Anderson, Jennifer A H; Owen, Micheal D K; Landes, Reid D

    2011-03-23

    Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and assesses the effectiveness in the detection of shikimic acid in the tissues of glyphosate-treated plants. Furthermore, the study evaluates the versatility of two acid-based shikimic acid extraction methods and assesses the longevity of plant extract samples under different storage conditions. Finally, Spec 1 and Spec 2 are further characterized with respect to (1) the capacity to discern between shikimic acid and chemically related alicyclic hydroxy acids, (2) the stability of the chromophore (t1/2), (3) the detection limits, and (4) the cost and simplicity of undertaking the analytical procedure. Overall, spectrophotometric methods were more cost-effective and simpler to execute yet provided a narrower detection limit compared to HPLC. All three methods were specific to shikimic acid and detected the compound in the tissues of glyphosate-susceptible crops, increasing exponentially in concentration within 24 h of glyphosate application and plateauing at approximately 72 h. Spec 1 estimated more shikimic acid in identical plant extract samples compared to Spec 2 and, likewise, HPLC detection was more effective than spectrophotometric determinations. Given the unprecedented global adoption of glyphosate-resistant crops and concomitant use of glyphosate, an effective and accurate assessment of glyphosate efficacy is important. Endogenous shikimic acid determinations are instrumental in corroborating the efficacy of glyphosate and therefore have numerous applications in herbicide research and related areas of science as well as resolving many commercial issues as a consequence of

  17. Enhanced anaerobic biological treatment of phenolic wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Kindzierski, W.B.

    1989-01-01

    The combined treatment requirements for a high strength phenolic wastewater were examined in batch and semicontinuous anaerobic methanogenic bioassays. Solvent extraction pretreatment and in-situ addition of activated carbon during anaerobic treatment were effective in removing phenol from a coal liquefaction wastewater from the H-coal process. The selective pH adjustment of high strength phenolic wastewater followed by diisopropyl ether extraction reduced the phenolic concentration to non-inhibitory levels, and removed non-phenolic inhibitory compounds. The weakly acid nature of phenol and substituted phenols allows for their selective removal by solvent extraction. Anaerobic bacteria were able to degrade phenol in the solvent extracted wastwater, however, the bacteria exhibited instability under semicontinuous feeding conditions. The addition of activated carbon to the stressed phenol-degrading cultures improved their ability to remove phenol from solution. Further investigation into the role activated carbon performed during anaerobic phenol treatment demonstrated its importance as a biological support, in addition to providing adsorptive capacity for organic (including inhibitory) compounds. The similar study of other support materials (ion exchange resins) which did not possess an adsorptive capacity for organic compounds supported these findings. Excellent agreement was demonstrated among physical evaluation methods, performance bioassays, radiolabelled cell adsorption studies, and scanning electron microscopy observations in judging the value of the materials as biological supports.

  18. Molecular design and genetic optimization of antimicrobial peptides containing unnatural amino acids against antibiotic-resistant bacterial infections.

    Science.gov (United States)

    He, Yongkang; He, Xiaofeng

    2016-09-01

    Antimicrobial peptides (AMPs) have been the focus of intense research towards the finding of a viable alternative to current small-molecule antibiotics, owing to their commonly observed and naturally occurring resistance against pathogens. However, natural peptides have many problems such as low bioavailability and high allergenicity that largely limit the clinical applications of AMPs. In the present study, an integrative protocol that combined chemoinformatics modeling, molecular dynamics simulations, and in vitro susceptibility test was described to design AMPs containing unnatural amino acids (AMP-UAAs). To fulfill this, a large panel of synthetic AMPs with determined activity was collected and used to perform quantitative structure-activity relationship (QSAR) modeling. The obtained QSAR predictors were then employed to direct genetic algorithm (GA)-based optimization of AMP-UAA population, to which a number of commercially available, structurally diverse unnatural amino acids were introduced during the optimization process. Subsequently, several designed AMP-UAAs were confirmed to have high antibacterial potency against two antibiotic-resistant strains, i.e. multidrug-resistant Pseudomonas aeruginosa (MDRPA) and methicillin-resistant Staphylococcus aureus (MRSA), with minimum inhibitory concentration (MIC) < 10 μg/ml. Structural dynamics characterizations revealed that the most potent AMP-UAA peptide is an amphipathic helix that can spontaneously embed into an artificial lipid bilayer and exhibits a strong destructuring tendency associated with the embedding process. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 746-756, 2016.

  19. Withaferin A protects against palmitic acid-induced endothelial insulin resistance and dysfunction through suppression of oxidative stress and inflammation.

    Science.gov (United States)

    Batumalaie, Kalaivani; Amin, Muhammad Arif; Murugan, Dharmani Devi; Sattar, Munavvar Zubaid Abdul; Abdullah, Nor Azizan

    2016-01-01

    Activation of inflammatory pathways via reactive oxygen species (ROS) by free fatty acids (FFA) in obesity gives rise to insulin resistance and endothelial dysfunction. Withaferin A (WA), possesses both antioxidant and anti-inflammatory properties and therefore would be a good strategy to suppress palmitic acid (PA)-induced oxidative stress and inflammation and hence, insulin resistance and dysfunction in the endothelium. Effect of WA on PA-induced insulin resistance in human umbilical vein endothelial cells (HUVECs) was determined by evaluating insulin signaling mechanisms whilst effect of this drug on PA-induced endothelial dysfunction was determined in acetylcholine-mediated relaxation in isolated rat aortic preparations. WA significantly inhibited ROS production and inflammation induced by PA. Furthermore, WA significantly decreased TNF-α and IL-6 production in endothelial cells by specifically suppressing IKKβ/NF-κβ phosphorylation. WA inhibited inflammation-stimulated IRS-1 serine phosphorylation and improved the impaired insulin PI3-K signaling, and restored the decreased nitric oxide (NO) production triggered by PA. WA also decreased endothelin-1 and plasminogen activator inhibitor type-1 levels, and restored the impaired endothelium-mediated vasodilation in isolated aortic preparations. These findings suggest that WA inhibited both ROS production and inflammation to restore impaired insulin resistance in cultured endothelial cells and improve endothelial dysfunction in rat aortic rings. PMID:27250532

  20. Cichoric Acid Reverses Insulin Resistance and Suppresses Inflammatory Responses in the Glucosamine-Induced HepG2 Cells.

    Science.gov (United States)

    Zhu, Di; Wang, Yutang; Du, Qingwei; Liu, Zhigang; Liu, Xuebo

    2015-12-30

    Cichoric acid, a caffeic acid derivative found in Echinacea purpurea, basil, and chicory, has been reported to have bioactive effects, such as anti-inflammatory, antioxidant, and preventing insulin resistance. In this study, to explore the effects of CA on regulating insulin resistance and chronic inflammatory responses, the insulin resistance model was constructed by glucosamine in HepG2 cells. CA stimulated glucosamine-mediated glucose uptake by stimulating translocation of the glucose transporter 2. Moreover, the production of reactive oxygen, the expression of COX-2 and iNOS, and the mRNA levels of TNF-α and IL-6 were attenuated. Furthermore, CA was verified to promote glucosamine-mediated glucose uptake and inhibited inflammation through PI3K/Akt, NF-κB, and MAPK signaling pathways in HepG2 cells. These results implied that CA could increase glucose uptake, improve insulin resistance, and attenuate glucosamine-induced inflammation, suggesting that CA is a potential natural nutraceutical with antidiabetic properties and anti-inflammatory effects. PMID:26592089

  1. 厌氧折流板反应器处理PTA废水及其相分离特性%Terephthalic acid(PTA) wastewater treated by anaerobic baffled reactor and its phase separation characteristics

    Institute of Scientific and Technical Information of China (English)

    杨忠林; 钟中; 韩萍芳; 吕效平

    2012-01-01

    The start-up and phase separation characteristics of the anaerobic baffled reactor (ABR) treating purified terephthalic acid (PTA) wastewater were investigated. Results showed that under these conditions the temperature was (35 ± 1) ℃ , hydraulic retention time was 40 h and volumetric loading rate was 3.60 kg/(m3·d) , the ABR started up successfully and the maximum removal efficiency of COD reached 80% after 62 d operation. The concentration of volatile fatty acids ( VFA) in the different compartments of ABR decreased along the flow direction, In contrast, the content of CH4 , the volatile suspended solid (VSS) , the ratio of VSS and the total suspended solid (TSS) , the specific methane production activities and the coenzyme F420 increased, the significant phase separation characteristics.%对厌氧折流板反应器(ABR)处理精对苯二甲酸(PTA)生产废水的启动及相分离过程进行研究.结果表明:经过62 d的运行,反应器在(35±1)℃、水力停留时间40 h、容积负荷3.60 kg/(m3·d)的条件下,最大COD去除率达到80%以上,ABR启动成功.沿着水流方向,不同格室中挥发性脂肪酸(VFA)浓度依次减小,CH4含量不断增加,且污泥中挥发性悬浮固体浓度(VSS)及其与总悬浮固体浓度(TSS)之比、产甲烷活性和辅酶F420不断增大,ABR中显示出显著的厌氧微生物相分离特性.

  2. Design and exploration of novel boronic acid inhibitors reveals important interactions with a clavulanic acid-resistant sulfhydryl-variable (SHV) β-lactamase.

    Science.gov (United States)

    Winkler, Marisa L; Rodkey, Elizabeth A; Taracila, Magdalena A; Drawz, Sarah M; Bethel, Christopher R; Papp-Wallace, Krisztina M; Smith, Kerri M; Xu, Yan; Dwulit-Smith, Jeffrey R; Romagnoli, Chiara; Caselli, Emilia; Prati, Fabio; van den Akker, Focco; Bonomo, Robert A

    2013-02-14

    Inhibitor resistant (IR) class A β-lactamases pose a significant threat to many current antibiotic combinations. The K234R substitution in the SHV β-lactamase, from Klebsiella pneumoniae , results in resistance to ampicillin/clavulanate. After site-saturation mutagenesis of Lys-234 in SHV, microbiological and biochemical characterization of the resulting β-lactamases revealed that only -Arg conferred resistance to ampicillin/clavulanate. X-ray crystallography revealed two conformations of Arg-234 and Ser-130 in SHV K234R. The movement of Ser-130 is the principal cause of the observed clavulanate resistance. A panel of boronic acid inhibitors was designed and tested against SHV-1 and SHV K234R. A chiral ampicillin analogue was discovered to have a 2.4 ± 0.2 nM K(i) for SHV K234R; the chiral ampicillin analogue formed a more complex hydrogen-bonding network in SHV K234R vs SHV-1. Consideration of the spatial position of Ser-130 and Lys-234 and this hydrogen-bonding network will be important in the design of novel antibiotics targeting IR β-lactamases.

  3. Saturated Fatty Acid Induces Insulin Resistance Partially Through Nucleotide-binding Oligomerization Domain 1 Signaling Pathway in Adipocytes

    Institute of Scientific and Technical Information of China (English)

    Yi-jun Zhou; Yin-si Tang; Yu-ling Song; Ai Li; Hui Zhou; Yan Li

    2013-01-01

    Objective To investigate the potential role of nucleotide-binding oligomerization domain 1 (NOD1), a component of the innate immune system, in mediating lipid-induced insulin resistance in adipocytes. Methods Adipocytes from Toll-like receptor 4 deficiency mice were used for stimulation experiments. The effect of oleate/palmitate mixture on nuclear factor-κB (NF-κB) activation was analyzed by reporter plasmid assay. The release of proinflammatory chemokine/cytokines production was determined by using real-time PCR. Insulin-stimulated glucose uptake was measured by 2-deoxy-D-[3H] glucose uptake assay. Chemokine/cytokine expression and glucose uptake in adipocytes transfected with small interfering RNA (siRNA) targeting NOD1 upon fatty acids treatment were analyzed. Results Oleate/palmitate mixture activated the NF-κB pathway and induced interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 mRNA expressions in adipocytes from mice deficient in Toll-like receptor 4, and these effects were blocked by siRNA targeting NOD1. Furthermore, saturated fatty acids decreased the ability of insulin-stimulated glucose uptake. Importantly, siRNA targeting NOD1 partially reversed saturated fatty acid-induced suppression of insulin-induced glucose uptake. Conclusion NOD1 might play an important role in saturated fatty acid-induced insulin resistance in adipocytes, suggesting a mechanism by which reduced NOD1 activity confers beneficial effects on insulin action.

  4. Feedback-Resistant Acetohydroxy Acid Synthase Increases Valine Production in Corynebacterium glutamicum

    OpenAIRE

    Elišáková, Veronika; Pátek, Miroslav; Holátko, Jiří; Nešvera, Jan; Leyval, Damien; Goergen, Jean-Louis; Delaunay, Stéphane

    2005-01-01

    Acetohydroxy acid synthase (AHAS), which catalyzes the key reactions in the biosynthesis pathways of branched-chain amino acids (valine, isoleucine, and leucine), is regulated by the end products of these pathways. The whole Corynebacterium glutamicum ilvBNC operon, coding for acetohydroxy acid synthase (ilvBN) and aceto hydroxy acid isomeroreductase (ilvC), was cloned in the newly constructed Escherichia coli-C. glutamicum shuttle vector pECKA (5.4 kb, Kmr). By using site-directed mutagenesi...

  5. Role of electrical resistance of electrodes in modeling of discharging and charging of flooded lead-acid batteries

    Science.gov (United States)

    Gandhi, K. S.

    2015-03-01

    Electrical resistance of both the electrodes of a lead-acid battery increases during discharge due to formation of lead sulfate, an insulator. Work of Metzendorf [1] shows that resistance increases sharply at about 65% conversion of active materials, and battery stops discharging once this critical conversion is reached. However, these aspects are not incorporated into existing mathematical models. Present work uses the results of Metzendorf [1], and develops a model that includes the effect of variable resistance. Further, it uses a reasonable expression to account for the decrease in active area during discharge instead of the empirical equations of previous work. The model's predictions are compared with observations of Cugnet et al. [2]. The model is as successful as the non-mechanistic models existing in literature. Inclusion of variation in resistance of electrodes in the model is important if one of the electrodes is a limiting reactant. If active materials are stoichiometrically balanced, resistance of electrodes can be very large at the end of discharge but has only a minor effect on charging of batteries. The model points to the significance of electrical conductivity of electrodes in the charging of deep discharged batteries.

  6. Fermentation and growth response of a primary poultry isolate of Salmonella typhimurium grown under strict anaerobic conditions in continuous culture and amino acid-limited batch culture.

    Science.gov (United States)

    Maciorowski, K G; Nisbet, D J; Ha, S D; Corrier, D E; DeLoach, J R; Ricke, S C

    1997-01-01

    Salmonella typhimurium is a significant hazard to consumer health that is carried asymptomatically in poultry gastrointestinal tracts. Nurmi cultures may prevent Salmonella colonization in young chicks, but the mechanism of competitive exclusion is unclear. Modeling Salmonella's metabolism in pure culture may allow for greater definition in choosing strains for Nurmi cultures. The growth rates and affinity constants of S. typhimurium growing in amino acid-limited conditions were determined in batch culture and compared to primary poultry isolates of cecal strains. Serine and NH4Cl were the best N sources for growth of all organisms tested in this study. The fermentation response of S. typhimurium was also monitored in continuous culture at a slow dilution rate of 0.021 h-1. S. typhimurium was found to adapt to VL media, with trends in protein disappearance, Yglucose, and Yprotein. This may show that amino acid or protein concentrations may be an integral component of the initial establishment of S. typhimurium in the cecum. PMID:9192013

  7. Fermentation and growth response of a primary poultry isolate of Salmonella typhimurium grown under strict anaerobic conditions in continuous culture and amino acid-limited batch culture.

    Science.gov (United States)

    Maciorowski, K G; Nisbet, D J; Ha, S D; Corrier, D E; DeLoach, J R; Ricke, S C

    1997-01-01

    Salmonella typhimurium is a significant hazard to consumer health that is carried asymptomatically in poultry gastrointestinal tracts. Nurmi cultures may prevent Salmonella colonization in young chicks, but the mechanism of competitive exclusion is unclear. Modeling Salmonella's metabolism in pure culture may allow for greater definition in choosing strains for Nurmi cultures. The growth rates and affinity constants of S. typhimurium growing in amino acid-limited conditions were determined in batch culture and compared to primary poultry isolates of cecal strains. Serine and NH4Cl were the best N sources for growth of all organisms tested in this study. The fermentation response of S. typhimurium was also monitored in continuous culture at a slow dilution rate of 0.021 h-1. S. typhimurium was found to adapt to VL media, with trends in protein disappearance, Yglucose, and Yprotein. This may show that amino acid or protein concentrations may be an integral component of the initial establishment of S. typhimurium in the cecum.

  8. Co-administration of glycyrrhizic acid with the antileishmanial drug sodium antimony gluconate (SAG) cures SAG-resistant visceral leishmaniasis.

    Science.gov (United States)

    Bhattacharjee, Amrita; Majumder, Saikat; Majumdar, Suchandra Bhattacharyya; Choudhuri, Soumitra Kumar; Roy, Syamal; Majumdar, Subrata

    2015-03-01

    Since there are very few affordable antileishmanial drugs available, antimonial resistance has crippled antileishmanial therapy, thereby emphasising the need for development of novel therapeutic strategies. This study aimed to evaluate the antileishmanial role of combined therapy with sodium antimony gluconate (SAG) and the triterpenoid glycyrrhizic acid (GA) against infection with SAG-resistant Leishmania (GE1F8R). Combination therapy with GA and SAG successfully limited infection with SAG-resistant Leishmania in a synergistic manner (fractional inhibitory concentration index resistant Leishmania and co-treated with GA and SAG exhibited a significant reduction in hepatic and splenic parasite burden. In probing the mechanism, it was observed that GA treatment suppressed the expression and efflux activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1), two host ABC transporters responsible for antimony efflux from host cells infected with SAG-resistant parasites. This suppression correlated with greater intracellular antimony retention during SAG therapy both in vitro and in vivo, which was reflected in the reduced parasite load. Furthermore, co-administration of GA and SAG induced a shift in the cytokine balance towards a Th1 phenotype by augmenting pro-inflammatory cytokines (such as IL-12, IFNγ and TNFα) and inducing nitric oxide generation in GE1F8R-infected macrophages as well as GE1F8R-infected mice. This study aims to provide an affordable leishmanicidal alternative to expensive antileishmanial drugs such as miltefosine and amphotericin B. Furthermore, this report explores the role of GA as a resistance modulator in MRP1- and P-gp-overexpressing conditions. PMID:25600891

  9. INDUCTION OF ANAEROBIC PROCESSES IN BAIKAL ENDEMICS EULIMNOGAMMARUS VITTATUS (DYB. AND E. VERRUCOSUS (DYB. (AMPHIPODA, CRUSTACEA

    Directory of Open Access Journals (Sweden)

    Timofeyev M.A.

    2006-03-01

    Full Text Available The data confirming the ability of Baikalian endemic species Eulimnogammarus vittatus (Dyb. and E. verrucosus (Dyb. to activate anaerobic glycolysis under hypoxia are presented. The differences in the degree and the rate of lactic acid accumulation and remetabolisation in returning to aerobiosis are noted in the species concerned. On the example of E. vittatus the ability of Baikalian endemics to activate anaerobic lipolysis and process of anaerobic formation of succinate is shown

  10. INDUCTION OF ANAEROBIC PROCESSES IN BAIKAL ENDEMICS EULIMNOGAMMARUS VITTATUS (DYB.) AND E. VERRUCOSUS (DYB.) (AMPHIPODA, CRUSTACEA)

    OpenAIRE

    Timofeyev M.A; Kirichenko K.A.; Rokhin A.V.; Bedulina D.S.; Chernyshova K.P.; Pobezhimova T.P.

    2006-01-01

    The data confirming the ability of Baikalian endemic species Eulimnogammarus vittatus (Dyb.) and E. verrucosus (Dyb.) to activate anaerobic glycolysis under hypoxia are presented. The differences in the degree and the rate of lactic acid accumulation and remetabolisation in returning to aerobiosis are noted in the species concerned. On the example of E. vittatus the ability of Baikalian endemics to activate anaerobic lipolysis and process of anaerobic formation of succinate is shown

  11. Pharmacokinetics of para-Aminosalicylic Acid in HIV-Uninfected and HIV-Coinfected Tuberculosis Patients Receiving Antiretroviral Therapy, Managed for Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis

    OpenAIRE

    de Kock, Lizanne; Sy, Sherwin K.B.; Rosenkranz, Bernd; Diacon, Andreas H; Prescott, Kim; Hernandez, Kenneth R.; Yu, Mingming; Derendorf, Hartmut; Donald, Peter R.

    2014-01-01

    The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis prompted the reintroduction of para-aminosalicylic acid (PAS) to protect companion anti-tuberculosis drugs from additional acquired resistance. In sub-Saharan Africa, MDR/XDR tuberculosis with HIV coinfection is common, and concurrent treatment of HIV infection and MDR/XDR tuberculosis is required. Out of necessity, patients receive multiple drugs, and PAS therapy is frequent; however, n...

  12. Anaerobic bacteria colonizing the lower airways in lung cancer patients

    Directory of Open Access Journals (Sweden)

    Anna Malm

    2011-07-01

    Full Text Available Anaerobes comprise most of the endogenous oropharyngeal microflora, and can cause infections of airways in lung cancer patients who are at high risk for respiratory tract infections. The aim of this study was to determine the frequency and species diversity of anaerobes in specimens from the lower airways of lung cancer patients. Sensitivity of the isolates to conventional antimicrobial agents used in anaerobe therapy was assessed. Respiratory secretions obtained by bronchoscopy from 30 lung cancer patients were cultured onto Wilkins- -Chalgren agar in anaerobic conditions at 37°C for 72–96 hours. The isolates were identified using microtest Api 20A. The minimal inhibitory concentrations for penicillin G, amoxicillin/clavulanate, piperacillin/tazobactam, cefoxitin, imipenem, clindamycin, and metronidazole were determined by E-test. A total of 47 isolates of anaerobic bacteria were detected in 22 (73.3% specimens. More than one species of anaerobe was found in 16 (53.3% samples. The most frequently isolated were Actinomyces spp. and Peptostreptococcus spp., followed by Eubacterium lentum, Veillonella parvula, Prevotella spp., Bacteroides spp., Lactobacillus jensenii. Among antibiotics used in the study amoxicillin/clavulanate and imipenem were the most active in vitro (0% and 2% resistant strains, respectively. The highest resistance rate was found for penicillin G and metronidazole (36% and 38% resistant strains, respectively. The results obtained confirm the need to conduct analyses of anaerobic microflora colonizing the lower respiratory tract in patients with lung cancer to monitor potential etiologic factors of airways infections, as well as to propose efficient, empirical therapy. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 2, pp. 263–266

  13. 腐植酸强化苯酚厌氧发酵降解%Intensification of phenol anaerobic biodegradation by humic acids

    Institute of Scientific and Technical Information of China (English)

    李培良; 王竞; 金若菲; 吕红; 柳广飞; 周集体

    2015-01-01

    在无外加电子受体的条件下,首次研究了腐植酸对活性污泥厌氧降解苯酚的影响.研究结果表明,腐植酸Suwannee River Humic Acid Standard(SR-HA)、Leonardite Humic Acid Standard(L-HA)和Pahokee Peat Humic Acid (PP-HA)作为氧化还原介体能够提高苯酚的厌氧发酵降解效率.其中腐植酸PP-HA对苯酚的厌氧降解表现出了最为明显的强化效果,反应进行36 h后,苯酚去除率提高了18.5%.当单独投加的PP-HA浓度在0至100 mg/L范围内,苯酚的厌氧降解效率随着腐植酸浓度增加而逐渐提高,而浓度大于100 mg/L后,腐植酸对苯酚降解效率的促进作用随着PP-HA浓度的增加逐渐减缓.除此之外,当低浓度的蒽醌-2-磺酸钠(AQS) (0.02 mM)和PP-HA (20 mg/L)在反应体系中共存时,相比于无介体存在的对照组,苯酚厌氧降解效率提高了约1.4倍.产物分析结果表明,乙酸和CH4作为苯酚发酵降解的重要产物被检测出来.最后,在氧化还原介体腐植酸的存在下,初步探讨了苯酚厌氧发酵降解的代谢途径.

  14. Biological hydrolysis and acidification of sludge under anaerobic conditions: The effect of sludge type and origin on the production and composition of olatile fatty acids

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Henze, Mogens

    2008-01-01

    New wastewater treatment processes resulting in considerably reduced sludge production and more effective treatment are needed. This is due to the more stringent legislations controlling discharges of wastewater treatment plants (WWTPs) and existing problems such as high sludge production....... In this study, the feasibility of implementing biological hydrolysis and acidification process on different types of municipal sludge was investigated by batch and semi-continuous experiments. The municipal sludge originated from six major treatment plants located in Denmark were used. The results showed...... that fermentation of primary sludge produced the highest amount of volatile fatty acids (VFAs) and generated significantly higher COD- and VFA-yields compared to the other sludge types regardless of which WWTP the sludge originated from. Fermentation of activated and primary sludge resulted in 1.9–5.6% and 8...

  15. Serum liver fatty acid binding protein levels correlate positively with obesity and insulin resistance in Chinese young adults.

    Directory of Open Access Journals (Sweden)

    Juan Shi

    Full Text Available BACKGROUND: Liver fatty acid-binding protein (FABP1 plays an inconclusive role in adiposity. We investigated the association of serum FABP1 levels with obesity and insulin resistance in Chinese young people under 30 years old. METHODOLOGY AND PRINCIPAL FINDINGS: Cross-sectional analysis including 200 obese and 172 normal-weight subjects matched for age and sex, anthropometric measurements were performed and serum FABP1 and biochemical characteristics were measured. Insulin resistance was determined by homeostasis model assessment of insulin resistance (HOMA-IR and by the insulin sensitivity index (S(i derived from Bergman's minimal model. FABP1 levels in obese subjects were significantly higher than those in normal-weight subjects (p<0.001 and the significance remained after adjustment for age, gender, alanine and aspartate aminotransferases (p<0.001. Serum FABP1 levels were significantly correlated with many metabolic-related parameters, with BMI and triglycerides as the independent determinants. FABP1 levels remained an independent risk factor of insulin resistance assessed by binary S(i (OR = 1.868 per SD unit, 95% CI [1.035-3.373], p = 0.038 after adjustment for age, sex, BMI, waist circumference, systolic blood pressure, serum triacylglycerol, total cholesterol, HDL- and LDL-cholesterol,. FABP1 levels were also elevated with an increasing number of components of the metabolic syndrome (p for trend <0.001. Multiple regression modeling for the MetS and its components demonstrated that hypertriglyceridemia and low HDL-cholesterol were significantly correlated to serum FABP1 levels. CONCLUSIONS AND SIGNIFICANCE: Serum FABP1 correlates positively with obesity and insulin resistance in Chinese young adults. Our data supports the fact that FABP1 might be an important mediator participating in fatty acid metabolism and energy balance.

  16. HIGH-RATE ANAEROBIC TREATMENT OF ALCOHOLIC WASTEWATERS

    Directory of Open Access Journals (Sweden)

    Florencio L.

    1997-01-01

    Full Text Available Modern high-rate anaerobic wastewater treatment processes are rapidly becoming popular for industrial wastewater treatment. However, until recently stable process conditions could not be guaranteed for alcoholic wastewaters containing higher concentrations of methanol. Although methanol can be directly converted into methane by methanogens, under specific conditions it can also be converted into acetate and butyrate by acetogens. The accumulation of volatile fatty acids can lead to reactor instability in a weakly buffered reactor. Since this process was insufficiently understood, the application of high-rate anaerobic reactors was highly questionable. This research investigated the environmental factors that are of importance in the predominance of methylotrophic methanogens over acetogens in a natural mixed culture during anaerobic wastewater treatment in upflow anaerobic sludge bed reactors. Technological and microbiological aspects were investigated. Additionally, the route by which methanol is converted into methane is also presented

  17. Decolourisation of textile wastewater in a submerged anaerobic membrane bioreactor.

    Science.gov (United States)

    Spagni, Alessandro; Casu, Stefania; Grilli, Selene

    2012-08-01

    Azo dye decolourisation can be easily achieved by biological reduction under anaerobic conditions. The aim of this study was to evaluate the applicability of submerged anaerobic membrane bioreactors (SAMBRs) for the decolourisation of dyeing wastewater containing azo dyes. The reactive orange 16 was used as model of an azo dye. The results demonstrated that very high decolourisation (higher than 99%) can be achieved by SAMBRs. Although decolourisation was not significantly influenced by the azo dye concentrations up to 3.2 g L(-1), methane production was greatly inhibited (up to 80-85%). Since volatile fatty acids accumulated in the treatment system with the azo dye concentration increase, methanogenes seem to be the most sensitive microbial populations of the anaerobic ecological community. The results demonstrated that anaerobic process combined with membrane filtration can deal with highly concentrated wastewaters that result from stream separation of industrial discharges.

  18. Characterization of Spartina alterniflora as feedstock for anaerobic digestion

    International Nuclear Information System (INIS)

    Smooth cordgrass (Spartina alterniflora), a saltmarsh plant with high production, was characterized for its potential for use as feedstock for anaerobic digestion processes. The anaerobic digestibility and biogas yield of S. alterniflora were evaluated by anaerobic batch digestion experiments performed at 35 ± 1 C at initial volatile solids (VS) of 6%. The nutrient content analysis indicated that S. alterniflora contained the required nutrition for anaerobic microorganisms, but its high C/N of 58.8, high K and Na contents of 8.1, 22.7 g kg-1, respectively, may be disadvantageous to its anaerobic digestion. The cumulative biogas yield was determined to be 358 L kg-1 VS and the biodegradation efficiency was 45% after 60 days of digestion. The methane content of biogas increased from 53% on day 3 to around 62% after 13 days of digestion. The changes of volatile fatty acids (VFAs) indicated that the acidification of S. alterniflora was propionate-type fermentation with proportion of acetate and propionate ranging from 54.8% to 98.4%, and the hydrolysis of lignocellulose was the rate-limiting step for its anaerobic digestion. The analysis of cations suggested that K+ and Mg2+, with the maximum concentration of 1.35 and 0.43 g L-1 in fermentation liquor, respectively, could be inhibitory to the anaerobic digestion of S. alterniflora. It is concluded that S. alterniflora can be transformed into clean energy by anaerobic digestion and the high contents of K, Na, Ca and Mg may be the inhibitory factors when S. alterniflora is digested by continuous or semi-continuous anaerobic process. (author)

  19. Anaerobic azo dye reduction

    OpenAIRE

    Zee, van der, KG Kristoffer

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo dyes and their breakdown products are toxic and/or mutagenic to life. To remove azo dyes from wastewater, a biological treatment strategy based on anaerobic reduction of the azo dyes, followed by aerobic transfo...

  20. Improvement of glyphosate resistance through concurrent mutations in three amino acids of the Ochrobactrum 5-enopyruvylshikimate-3-phosphate synthase.

    Science.gov (United States)

    Tian, Yong-Sheng; Xu, Jing; Xiong, Ai-Sheng; Zhao, Wei; Fu, Xiao-Yan; Peng, Ri-He; Yao, Quan-Hong

    2011-12-01

    A mutant of 5-enopyruvylshikimate-3-phosphate synthase from Ochrobactrum anthropi was identified after four rounds of DNA shuffling and screening. Its ability to restore the growth of the mutant ER2799 cell on an M9 minimal medium containing 300 mM glyphosate led to its identification. The mutant had mutations in seven amino acids: E145G, N163H, N267S, P318R, M377V, M425T, and P438L. Among these mutations, N267S, P318R, and M425T have never been previously reported as important residues for glyphosate resistance. However, in the present study they were found by site-directed mutagenesis to collectively contribute to the improvement of glyphosate tolerance. Kinetic analyses of these three mutants demonstrated that the effectiveness of these three individual amino acid alterations on glyphosate tolerance was in the order P318R > M425T > N267S. The results of the kinetic analyses combined with a three-dimensional structure modeling of the location of P318R and M425T demonstrate that the lower hemisphere's upper surface is possibly another important region for glyphosate resistance. Furthermore, the transgenic Arabidopsis was obtained to confirm the potential of the mutant in developing glyphosate-resistant crops.

  1. Ultraviolet light and ozone stimulate accumulation of salicylic acid, pathogenesis-related proteins and virus resistance in tobacco

    International Nuclear Information System (INIS)

    In tobacco (Nicotiana tabacum L. cv. Xanthinc), salicylic acid (SA) levels increase in leaves inoculated by necrotizing pathogens and in healthy leaves located above the inoculated site. Systemic SA increase may trigger disease resistance and synthesis of pathogenesis-related proteins (PR proteins). Here we report that ultraviolet (UV)-C light or ozone induced biochemical responses similar to those induced by necrotizing pathogens. Exposure of leaves to UV-C light or ozone resulted in a transient ninefold increase in SA compared to controls. In addition, in UV-light-irradiated plants, SA increased nearly fourfold to 0.77 μg·g−1 fresh weight in leaves that were shielded from UV light. Increased SA levels were accompanied by accumulation of an SA conjugate and by an increase in the activity of benzoic acid 2-hydroxylase which catalyzes SA biosynthesis. In irradiated and in unirradiated leaves of plants treated with UV light, as well as in plants fumigated with ozone, PR proteins 1a and 1b accumulated. This was paralleled by the appearance of induced resistance to a subsequent challenge with tobacco mosaic virus. The results suggest that UV light, ozone fumigation and tobacco mosaic virus can activate a common signal-transduction pathway that leads to SA and PR-protein accumulation and increased disease resistance. (author)

  2. In vitro activity of trovafloxacin against Bacteroides fragilis in mixed culture with either Escherichia coli or a vancomycin- resistant strain of Enterococcus faecium determined by an anaerobic time-kill technique.

    NARCIS (Netherlands)

    L.E.T. Stearne (Lorna); C. Kooi; W.H.F. Goessens (Wil); I.A.J.M. Bakker-Woudenberg (Irma); I.C. Gyssens (Inge)

    2001-01-01

    textabstractTo determine the efficacy of trovafloxacin as a possible treatment for intra-abdominal abscesses, we have developed an anaerobic time-kill technique using different inocula to study the in vitro killing of Bacteroides fragilis in pure culture or in mixed cul

  3. Isolation and characterization of an anaerobic ruminal bacterium capable of degrading hydrolyzable tannins.

    OpenAIRE

    Nelson, K E; A. N. Pell; Schofield, P; Zinder, S

    1995-01-01

    An anaerobic diplococcoid bacterium able to degrade hydrolyzable tannins was isolated from the ruminal fluid of a goat fed desmodium (Desmodium ovalifolium), a tropical legume which contains levels as high as 17% condensed tannins. This strain grew under anaerobic conditions in the presence of up to 30 g of tannic acid per liter and tolerated a range of phenolic monomers, including gallic, ferulic, and p-coumaric acids. The predominant fermentation product from tannic acid breakdown was pyrog...

  4. Efficient methane production from lipid-rich wastewater in high-rate anaerobic treatment

    OpenAIRE

    Cavaleiro, A. J.; Salvador, A. F.; Alves, M. M.

    2008-01-01

    In this work, high rate anaerobic mineralization of a synthetic dairy effluent containing 50% COD as oleic acid was accomplished in two reactors operated in parallel. The anaerobic reactors were able to accommodate organic loading rates up to 21 kg COD m-3 day-1, HRT of 9 hours, attaining 99% of soluble COD removal efficiency and methane yield higher than 70%. Long chain fatty acids (LCFA) accumulated inside the reactor only during the last two phases of operation and palmitic acid was ...

  5. 酸碱预处理对稻草秸秆发酵产氢的影响%Effect of acid and alkaline pretreatment on bio-hydrogen production from rice straw by anaerobic fermentation

    Institute of Scientific and Technical Information of China (English)

    潘晶; 于龙; 王楠

    2012-01-01

    Hydrogen, as a clean energy that can replace conventional fossil fuels, is attracting worldwide attentions. Bio-hydrogen production process with anaerobic fermentation resolves the organic waste by the biological technology to produce hydrogen with simple equipments, easy manipulation and low cost. Effects of acid and alkaline pretreatment on bio-hydrogen production from rice straw by anaerobic sludge fermentation were studied. The results show that H2SO4 pretreatment is the best one. Rice straw with 1% H2SO4 pretreatment, the maximum hydrogen concentration, the highest specific hydrogen production yield rate and the highest hydrogen production yield were respectively 47. 68% 、4. 67 mL/( h · g) and 59. 21 mL/g. With 1 % NaOH pretreatment, the maximum hydrogen concentration, the highest specific hydrogen production yield rate and the highest hydrogen production yield were respectively 41.92% 、3. 24 mL/( h · g) and 42.02 mL/g. The produced volatile fatty acids in the fermentation solutions are mainly ethanol, acetate and butyrate.%随着环保要求的日益严格和化石能源的日益短缺,氢能作为清洁高效的可再生能源受到人们的普遍重视.厌氧发酵生物制氢是利用生物技术分解有机废弃物制备氢气,该工艺设备简单、操作容易、成本低廉等优点.以稻草秸秆为发酵底料,以厌氧活性污泥为接种物,研究酸碱预处理对秸秆发酵产氢的影响.结果表明,H2SO4预处理为最佳的预处理方式;稻草秸秆经1%的H2SO4预处理后发酵气中氢气的最大含量、最高比产氢速率和最高氢气产率分别为47.68%、4.67mL/(h·g)和59.21mL/g;经1%的NaOH预处理后发酵气中氢气的最大含量、最高比产氢速率和最高氢气产率分别为41.92%、3.24mL/(h·g)和42.02mL/g;发酵液相中主要产物为乙醇、乙酸和丁酸.

  6. A new class of IMP dehydrogenase with a role in self-resistance of mycophenolic acid producing fungi

    Directory of Open Access Journals (Sweden)

    Mortensen Uffe H

    2011-09-01

    Full Text Available Abstract Background Many secondary metabolites produced by filamentous fungi have potent biological activities, to which the producer organism must be resistant. An example of pharmaceutical interest is mycophenolic acid (MPA, an immunosuppressant molecule produced by several Penicillium species. The target of MPA is inosine-5'-monophosphate dehydrogenase (IMPDH, which catalyses the rate limiting step in the synthesis of guanine nucleotides. The recent discovery of the MPA biosynthetic gene cluster from Penicillium brevicompactum revealed an extra copy of the IMPDH-encoding gene (mpaF embedded within the cluster. This finding suggests that the key component of MPA self resistance is likely based on the IMPDH encoded by mpaF. Results In accordance with our hypothesis, heterologous expression of mpaF dramatically increased MPA resistance in a model fungus, Aspergillus nidulans, which does not produce MPA. The growth of an A. nidulans strain expressing mpaF was only marginally affected by MPA at concentrations as high as 200 μg/ml. To further substantiate the role of mpaF in MPA resistance, we searched for mpaF orthologs in six MPA producer/non-producer strains from Penicillium subgenus Penicillium. All six strains were found to hold two copies of IMPDH. A cladistic analysis based on the corresponding cDNA sequences revealed a novel group constituting mpaF homologs. Interestingly, a conserved tyrosine residue in the original class of IMPDHs is replaced by a phenylalanine residue in the new IMPDH class. Conclusions We identified a novel variant of the IMPDH-encoding gene in six different strains from Penicillium subgenus Penicillium. The novel IMPDH variant from MPA producer P. brevicompactum was shown to confer a high degree of MPA resistance when expressed in a non-producer fungus. Our study provides a basis for understanding the molecular mechanism of MPA resistance and has relevance for biotechnological and pharmaceutical applications.

  7. Sensory Description of Cultivars (Coffea Arabica L. Resistant to Rust and Its Correlation with Caffeine, Trigonelline, and Chlorogenic Acid Compounds

    Directory of Open Access Journals (Sweden)

    Larissa de Oliveira Fassio

    2016-01-01

    Full Text Available Considering the importance of the chemical compounds in Arabica coffee beans in the definition of the drink sensory quality and authentication of coffee regions, the aim of this study was to evaluate, from principal component analysis—PCA—if there is a relation between the caffeine, trigonelline, and chlorogenic acid (5-CQA content and the sensory attributes of the drink, and in this context, enabling the differentiation of cultivars in two coffee-producing regions of Brazil. We evaluated seven rust-resistant Coffea arabica cultivars, and two rust-susceptible cultivars in two cultivation environments: Lavras, in the southern region of Minas Gerais state, and Patrocinio in the Cerrado region of Minas Gerais. The flavor and acidity were determinant for differentiation of the cultivars and their interaction with the evaluated environments. Cultivars Araponga MG1, Catigua MG2, and Catigua MG1 are the most suitable for the production of specialty coffee in the state of Minas Gerais. A poor correlation was found between caffeine, trigonelline, 5-CQA contents, and fragrance, flavor, acidity, body, and final score attributes. However, these compounds enabled the differentiation of the environments. The PCA indicated superiority in the sensory quality of cultivars resistant to rust, compared to the control, Bourbon Amarelo, and Topázio MG1190.

  8. Study of the resistance of SAMs on aluminium to acidic and basic solutions using dynamic contact angle measurement.

    Science.gov (United States)

    Liakos, Ioannis L; Newman, Roger C; McAlpine, Eoghan; Alexander, Morgan R

    2007-01-30

    We report the development of a method to determine the aqueous stability of self-assembled monolayers (SAMs) using the Wilhelmy plate dynamic contact angle (DCA) experiment. The DCA is measured in solutions over a range of pH values for alkyl carboxylic and alkyl phosphonic acid SAMs formed on magnetron-sputtered aluminum. The change in DCA on repeated immersion is used as a measure of the degradation of the SAMs by hydrolytic attack. The short and intermediate chain length alkyl acids are not stable in water of neutral pH, whereas molecules with the longest alkyl chains show considerably greater stability in neutral and both high and low pH solutions. The packing density inferred from the DCA and the contact angle hysteresis suggests the C18CO2H monolayer to be slightly less well packed than that of the C18P(=O)(OH)2; this is consistent with related friction force microscopy and infrared reflection absorption spectroscopy findings published elsewhere (Foster, T. T.; Alexander, M. R.; Leggett, G. J.; McAlpine, E. Langmuir 2006, 22, 9254-9259). The resistance of the SAMs to acid and alkaline environments is discussed in the context of aluminum oxide solubility, SAM packing density, and the resistance of the interfacial phosphate and carboxylate functionalities to different aqueous conditions. PMID:17241003

  9. [First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología].

    Science.gov (United States)

    Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C

    2011-01-01

    Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown.

  10. [First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología].

    Science.gov (United States)

    Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C

    2011-01-01

    Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown. PMID:21491069

  11. Effect of Copper Addition on Corrosion Resistance of Austenitic Stainless Steel in Highly Concentrated Sulfuric Acid Solution

    International Nuclear Information System (INIS)

    Effect of Cu addition on corrosion resistance of austenitic stainless steel in 18.4N H2SO4 at 80 ∼ 120 .deg. C was investigated through anodic polarization test, cathodic polarization test, long-term immersion test and Auger surface analysis. The addition of 3.2% Cu in the alloy enhanced the corrosion resistance greatly in highly concentrated sulfuric acid by decreasing corrosion current density, current density of hydrogen evolution, critical current density and passivation current density. The dissolution rates of each of the elements in the alloy resembled that of the elements in pure metal form. The reason why Cu improved the corrosion resistance was that cathodic reaction and anodic dissolution in the active region were retarded by the protective surface film now heavily enriched with Cu through selective dissolution of Fe, Ni and Cr. The stainless steel with 18%Cr-21%Ni-3.2%Mo-1.6%W-0.2%N- 3.2%Cu-0.035%C displayed a noticeably better corrosion resistance than the commercial super austenitic stainless steel such as 654SMO and at least as good as Ni-base alloy such as CW12MW in SO42- environment

  12. Effect of Copper Addition on Corrosion Resistance of Austenitic Stainless Steel in Highly Concentrated Sulfuric Acid Solution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soon Tae; Park, Yong Soo [Yonsei University, Seoul (Korea, Republic of); Kim, Hyung Joon [POSCO Technical Research Laboratories, Pohang (Korea, Republic of)

    1999-08-15

    Effect of Cu addition on corrosion resistance of austenitic stainless steel in 18.4N H{sub 2}SO{sub 4} at 80 {approx} 120 .deg. C was investigated through anodic polarization test, cathodic polarization test, long-term immersion test and Auger surface analysis. The addition of 3.2% Cu in the alloy enhanced the corrosion resistance greatly in highly concentrated sulfuric acid by decreasing corrosion current density, current density of hydrogen evolution, critical current density and passivation current density. The dissolution rates of each of the elements in the alloy resembled that of the elements in pure metal form. The reason why Cu improved the corrosion resistance was that cathodic reaction and anodic dissolution in the active region were retarded by the protective surface film now heavily enriched with Cu through selective dissolution of Fe, Ni and Cr. The stainless steel with 18%Cr-21%Ni-3.2%Mo-1.6%W-0.2%N- 3.2%Cu-0.035%C displayed a noticeably better corrosion resistance than the commercial super austenitic stainless steel such as 654SMO and at least as good as Ni-base alloy such as CW12MW in SO{sub 4}{sup 2-} environment.

  13. Anaerobic treatment of phthalates

    OpenAIRE

    Kleerebezem, R.

    1999-01-01

    Phthalic acid isomers (dicarboxy benzenes) play an important role in our human environment as constituents of polyester fibres, films, polyethylene terephthalate (PET) bottles and other plastics. Due to the use and generation of water during phthalic acid production from the corresponding xylenes, a concentrated wastewater is generated. The generated wastewater consists of a mixture of phthalic acid isomers, acetic acid, benzoic acid, and toluic acids. The aim of the work described in this th...

  14. Kinetics of biogas production in Anaerobic Filters.

    Science.gov (United States)

    Krümpel, Johannes; Schäufele, Friedrich; Schneider, Johannes; Jungbluth, Thomas; Zielonka, Simon; Lemmer, Andreas

    2016-01-01

    This study investigates methane production kinetics from individual volatile fatty acids (VFA) in an Upflow Anaerobic Filter (AF). 1gCOD in the form of acetic (HAc), propionic (HPr) or butyric acid (HBu) was injected into the AF while operating at an organic loading rate (OLRCOD) of 3.5gL(-1)d(-1). A new method is introduced to separate gas production of the baseload from the product formation of VFA degradation after the injection. The lag phase, fractional rate of gas production and half-life has been determined for the methane production of the three VFAs. The half-lives were in the order HAcgas production from the C3 acid than from the C4 acid. The results can be used for prediction models for on-demand biogas production, a vital approach that provides the transforming energy market with balancing power. PMID:26492176

  15. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;

    2001-01-01

    requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader......The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...

  16. Implementation of online volatile fatty acids sensor for control and optimization of anaerobic process for low cost biogas production from manure. Project report

    Energy Technology Data Exchange (ETDEWEB)

    Boe, K.; Angelidaki, I.

    2010-10-15

    Proper monitoring and control can improve process stability and enhance process performance for better economy of the biogas plants. Volatile fatty acid (VFA) is the most widely recognized as a direct, relevant measure of stability. Classic on-line measurement of individual VFA is based on filtration, which suffers from fouling when applied with manure slurries. A VFA sensor developed at DTU Environment, based on headspace chromatography technique could avoid the problems from particulate matters. In this work, the sensor had been implemented for online monitoring of the lab-scale and the pilot-scale manure digester. The industrial prototype of the VFA sensor and sample acquisition system has been constructed and implemented at a pilot scale biogas plant, located at Lundtofte, DTU. The VFA sensor has shown very satisfying results in terms of sensitivity and reliability for monitoring the biogas process. Moreover, the online VFA and biogas registration data were used as process indicators for automatic control of the biogas reactor. The results from control experiments confirmed that the combination of biogas production, total VFA concentration and propionate concentration could effectively reflect the dynamic state of the process which was very crucial for automatic control. Due to the standardized analyzing condition (pH<2, temperature>70 deg. C), the sensor responses were not affected by the manure composition (TS, VS or the addition of extra organics), which made these results representative for implementing in the full-scale biogas plant where some industrial organic wastes were added to increase the biogas production. During the project period, the sensor design and construction had been modified and tested several times to improve the robustness. However, the implementation of the sensor in full-scale biogas plant would need some further development such as improvement of mechanical design and further up-scaling depending on the dry solid content in the

  17. Study on the Acid Resistance of Silver Paste%厚膜导体银浆耐酸性研究

    Institute of Scientific and Technical Information of China (English)

    付明; 陈栋; 吕文中; 汪小红

    2011-01-01

    Lead- free glass frits of Bi2O3 - B2O3 - SiO2 materials were developed by high temperature melting and water quenching methods, and the silver conductive paste was prepared by using above glass frits. The effect of the softening point(Tg) and content of glass frits on the acid resistance of silver paste were discussed. The results showed that, the Tg are very important parameter to the acid resistance of silver films. The acid resistance properties of silver films were improved by adding suitable amount of Al2O3 and TiO2. The micro crystallized glass frits were made by adjusting the ratio of ZnO and Al2O3 to precipitate ( ZnAl2O4 ) crystals. The silver paste, which meet the processing conditions and have a excellent acid resistance characteristics ,were prepared by using low Tg lead -free glass.%采用高温熔炼水淬法,制备了Bi2O3-B2O3-SiO2系无铅玻璃料,并利用该玻璃料制得厚膜导体银浆.研究了玻璃料组分及其软化温度(Tg)等对银浆耐酸性的影响.结果表明,玻璃料Tg对银浆的耐酸性能产生直接影响,加入适量TiO2和Al2O3能改善银膜的耐酸性.当玻璃料中ZnO与Al2O3的配比在某些值时,该玻璃料可在一定温度范围内析出锌尖晶石(ZnAl2O4),大大加强了银浆的耐酸性.作者利用无铅玻璃料研制出既能满足一定烧结工艺,又具有优良耐酸性能的厚膜导体银浆.

  18. A Novel Thin Film Resistive Humidity Sensor Based on Soluble Conjugated Polymer: (propionic acid)-co-(propargyl alcohol)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)2 (CoCC(CH3)2OH)2 (PPB). Thin film resistive humidity sensor based on the copolymer doped with HClO-4 was prepared. The impedance of the sensor changed from 103~107 W in 95%~30%RH, and the response of that is very quick (<6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.

  19. Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides

    Science.gov (United States)

    An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. The corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was partially controlled by ...

  20. The potential benefits of creatine and conjugated linoleic acid as adjuncts to resistance training in older adults.

    Science.gov (United States)

    Tarnopolsky, Mark A; Safdar, Adeel

    2008-02-01

    Human aging is associated with a significant reduction in muscle mass (sarcopenia) resulting in muscle weakness and functional limitations in the elderly. Sarcopenia has been associated with mitochondrial dysfunction and the accumulation of mtDNA deletions. Resistance training increases muscle strength and size and can increase mitochondrial capacity and decrease oxidative stress in older adults. Creatine monohydrate (CrM) and conjugated linoleic acid (CLA) have biological effects that could enhance some of the beneficial effects of resistance training in older adults (i.e., up arrow fat-free mass, down arrow total body fat). We have completed two resistance-training studies with CrM alone and CrM+CLA supplementation in older adults to evaluate the independent effects of exercise and dietary supplements, as well as their interactive effects. Our studies, and several others, have found that CrM enhanced the resistance exercise mediated gains in fat-free mass and strength. More recently, we found that the addition of CLA also lead to a significant reduction of body fat after six months of resistance training in older adults. Older adults have fewer wild-type mtDNA copies and higher amounts of mtDNA deletions as compared with younger adults in mature skeletal muscle; however, these deletions are not seen in the satellite cell-derived myoblast cultures. These findings, and the fact that mtDNA deletions are lower and wild-type mtDNA copy number is higher after resistance training in older adults, suggests that activation of satellite cells secondary to resistance exercise-induced muscle damage can dilute or "shift" the proportion of mtDNA genotype towards that of a younger adult. Recent evidence suggests that CrM supplementation in combination with strength training can enhance satellite cell activation and total myonuclei number per muscle fiber in young men. Future studies are required to determine whether the mitochondrial adaptations to resistance exercise in older

  1. Improvement of anaerobic digestion of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Dohanyos, Michael; Zabranska, Jana; Kutil, Josef; Jenicek, Pavel

    2003-07-01

    Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of process conditions is frequently used pretreatment of input sludge and increase of process temperature. Thermophilic process brings a higher solids reduction and biogas production, the high resistance to foaming, no problems with odour, the higher effect of destroying pathogens and the improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in lysate centrifuge was proved in full-scale conditions causing increase of biogas production. The rapid thermal conditioning of digested sludge is acceptable method of particulate matter disintegration and solubilization. (author)

  2. Burdock fructooligosaccharide induces fungal resistance in postharvest Kyoho grapes by activating the salicylic acid-dependent pathway and inhibiting browning.

    Science.gov (United States)

    Sun, Fei; Zhang, Pengying; Guo, Moran; Yu, Wenqian; Chen, Kaoshan

    2013-05-01

    Burdock fructooligosaccharide (BFO) is a natural elicitor from Arcitum lappa. The effects of BFO in controlling postharvest disease in grape, apple, banana, kiwi, citrus, strawberry, and pear were investigated. The disease index, decay percentage, and area under the disease progress curve indicated that BFO has general control effects on postharvest disease of fruits. Kyoho grapes were studied to elucidate the mechanism of BFO in boosting the resistance of grapes to Botrytis cinerea infection. BFO treatment induced upregulation of the npr1, pr1, pal, and sts genes, and inhibited the total phenol content decrease, which activated chitinase and β-1,3-glucanase. These results indicated that the salicylic acid-dependent signalling pathway was induced. The delayed colour change and peroxidase and polyphenoloxidase activity suggested that BFO delayed grape browning. The reduced respiration rate, weight loss, and titratable acidity prolonged the shelf life of postharvest grapes. BFO is a promising elicitor in postharvest disease control.

  3. Corrosion Resistance of Electroless Ni-Cu-P Ternary Alloy Coatings in Acidic and Neutral Corrosive Mediums

    Directory of Open Access Journals (Sweden)

    Mbouillé Cissé

    2010-01-01

    Full Text Available Electroless Ni-Cu-P alloy coatings were deposited on the ordinary steel substrate in an acidic hypophosphite-type plating bath. These coatings were characterized by a scanning electron microscope (SEM and an X-ray diffraction. The micrograph shows that coating presents a nodular aspect and is relatively homogeneous and very smooth. The EDX analysis shows that the coating contains 12 wt.% of phosphorus element with a predominance of nickel element. In addition, the anticorrosion properties of the Ni-Cu-P coatings in 1 M HCl, 1 M H2SO4, and 3% NaCl solutions were investigated using Tafel polarization curves, electrochemical impedance spectroscopy, and SEM/EDX analysis. The result showed a marginal improvement in corrosion resistance in 3% NaCl solution compared to acidic medium. It also showed that the corrosion mechanism depends on the nature of the solution.

  4. Identification and Characterization of Mutations Conferring Resistance to d-Amino Acids in Bacillus subtilis

    OpenAIRE

    Leiman, Sara A.; Richardson, Charles; Foulston, Lucy; Elsholz, Alexander K.W.; First, Eric A.; Losick, Richard

    2015-01-01

    Bacteria produce d-amino acids for incorporation into the peptidoglycan and certain nonribosomally produced peptides. However, d-amino acids are toxic if mischarged on tRNAs or misincorporated into protein. Common strains of the Gram-positive bacterium Bacillus subtilis are particularly sensitive to the growth-inhibitory effects of d-tyrosine due to the absence of d-aminoacyl-tRNA deacylase, an enzyme that prevents misincorporation of d-tyrosine and other d-amino acids into nascent proteins. ...

  5. Aluminium resistance requires resistance to acid stress: a case study with spinach that exudes oxalate rapidly when exposed to Al stress.

    Science.gov (United States)

    Yang, Jian Li; Zheng, Shao Jian; He, Yun Feng; Matsumoto, Hideaki

    2005-04-01

    Spinach is a vegetable with a high oxalate concentration in its tissues. Oxalate efflux from spinach (Spinacia oleracea L. cv. Quanneng) roots was rapidly stimulated (within 30 min) by aluminium (Al) treatment. The efflux was constant within 6 h, but increased with increasing Al concentration. The efflux was confined to the root tip (0-5 mm), which showed a 5-fold greater efflux than the root zone distal to the tip (5-10 mm). Oxalate efflux could not be triggered by treatment with the trivalent cation lanthanum or by phosphorus deficiency, indicating that the efflux was specific to the Al treatment. All this evidence suggested that spinach possesses Al-resistance mechanisms. However, spinach was found to be as sensitive to Al toxicity as the Al-sensitive wheat line ES8, which had no Al-dependent organic acids efflux. The Al accumulated in the apical 5 mm of the roots of spinach which was also similar to that in the Al-sensitive wheat after 24 h treatment with 50 microM AlCl(3), indicating a non-exclusion mechanism. In addition, root elongation in spinach was significantly inhibited at pH 4.5, compared with that at pH 6.5. Based on this evidence, it is concluded that the sensitivity to acid stress in spinach could mask the potential role for oxalate to protect the plant roots from Al toxicity.

  6. Downy mildew (Peronospora parasitica) resistance genes in Arabidopsis vary in functional requirements for NDR1, EDS1, NPR1 and salicylic acid accumulation.

    Science.gov (United States)

    McDowell, J M; Cuzick, A; Can, C; Beynon, J; Dangl, J L; Holub, E B

    2000-06-01

    To better understand the genetic requirements for R gene-dependent defense activation in Arabidopsis, we tested the effect of several defense response mutants on resistance specified by eight RPP genes (for resistance to Peronospora parasitica) expressed in the Col-0 background. In most cases, resistance was not suppressed by a mutation in the SAR regulatory gene NPR1 or by expression of the NahG transgene. Thus, salicylic acid accumulation and NPR1 function are not necessary for resistance mediated by these RPP genes. In addition, resistance conferred by two of these genes, RPP7 and RPP8, was not significantly suppressed by mutations in either EDS1 or NDR1. RPP7 resistance was also not compromised by mutations in EIN2, JAR1 or COI1 which affect ethylene or jasmonic acid signaling. Double mutants were therefore tested. RPP7 and RPP8 were weakly suppressed in an eds1-2/ndr1-1 background, suggesting that these RPP genes operate additively through EDS1, NDR1 and as-yet-undefined signaling components. RPP7 was not compromised in coi1/npr1 or coi1/NahG backgrounds. These observations suggest that RPP7 initiates resistance through a novel signaling pathway that functions independently of salicylic acid accumulation or jasmonic acid response components.

  7. Influence of jasmonic acid as potential activator of induced resistance against Karnal bunt in developing spikes of wheat

    Indian Academy of Sciences (India)

    Mihir K Mandal; Dinesh Pandey; Shalini Purwar; U S Singh; Anil Kumar

    2006-12-01

    Induction of defense response against Karnal bunt (KB) by suppressing the pathogenesis was observed upon exogenous application of jasmonic acid (JA) as evident from decrease in the coefficient of infection and overall response value in both susceptible and resistant varieties of wheat. The ultra-structural changes during disease progression showed the signs of programmed cell death (PCD). However, JA strengthened the defense barrier by enhancing the lignifications of cell walls as observed in spikes of both varieties by histochemical analysis. Compared to the plants inoculated with pathogen alone, plants of resistant line (RJP) first treated with JA followed by inoculation with pathogen showed more lignifications and extracellular deposition of other metabolites on cells, which is supposed to prevent mycelial invasions. Contrary to this, susceptible (SJP) lines also showed lignifications but the invasion was more compared to resistant line. Induction of protease activity was higher in resistant variety than its corresponding susceptible variety. The protease activity induced during the colonization of the pathogen and its proliferation inside the host system gets inhibited by JA treatment as demonstrated by the quantitative and in-gel protease assay. The results indicate the role of JA signalling in inhibiting the proteases due to expression of certain protease inhibitor genes. SDS-PAGE analysis shows differential gene expression through induction and/or suppression of different proteins in wheat spikes of resistant and susceptible varieties under the influence of JA. Thus, exogenously applied JA provides the conditioning effect prior to the challenge of infection and induces defense against KB probably by maintaining a critical balance between proteases and protease inhibitors and/or coordinating induction of different families of new proteins.

  8. Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Alatriste-Mondragon, Felipe; Iranpour, R.;

    2003-01-01

    Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants. Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge. To date, many studies exist on the anaerobic biodegradation rates of PAE, especially...... of the easily biodegradable ones, whereas the higher molecular weight PAE have reported to be non-biodegradable under methanogenic conditions. Furthermore, there is no information on the effect of the PAE on the performance of the anaerobic digesters treating sludge. In this study, the anaerobic biodegradation...... of di-n-butyl phthalate (DBP), di-ethyl phthalate (DEP) and di-ethylhexyl phthalate (DEHP) was investigated and their relative rates of anaerobic degradation were calculated. Also, the biological removal of PAE during the anaerobic digestion of sludge in bench-scale digesters was investigated using DBP...

  9. The Lys234Arg Substitution in the Enzyme SHV-72 Is a Determinant for Resistance to Clavulanic Acid Inhibition▿

    Science.gov (United States)

    Mendonça, Nuno; Manageiro, Vera; Robin, Frédéric; Salgado, M. José; Ferreira, Eugénia; Caniça, Manuela; Bonnet, Richard

    2008-01-01

    The new β-lactamase SHV-72 was isolated from clinical Klebsiella pneumoniae INSRA1229, which exhibited the unusual association of resistance to the amoxicillin-clavulanic acid combination (MIC, 64 μg/ml) and susceptibility to cephalosporins, aztreonam, and imipenem. SHV-72 (pI 7.6) harbored the three amino acid substitutions Ile8Phe, Ala146Val, and Lys234Arg. SHV-72 had high catalytic efficiency against penicillins (kcat/Km, 35 to 287 μM−1·s−1) and no activity against oxyimino β-lactams. The concentration of clavulanic acid necessary to inhibit the enzyme activity by 50% was 10-fold higher for SHV-72 than for SHV-1. Molecular-dynamics simulation suggested that the Lys234Arg substitution in SHV-72 stabilized an atypical conformation of the Ser130 side chain, which moved the Oγ atom of Ser130 around 3.5 Å away from the key Oγ atom of the reactive serine (Ser70). This movement may therefore decrease the susceptibility to clavulanic acid by preventing cross-linking between Ser130 and Ser70. PMID:18316518

  10. Structure and properties of moisture-resistant konjac glucomannan films coated with shellac/stearic acid coating.

    Science.gov (United States)

    Wei, Xueqin; Pang, Jie; Zhang, Changfeng; Yu, Chengcheng; Chen, Han; Xie, Bingqing

    2015-03-15

    A series of moisture-resistant konjac glucomannan films were prepared by coating shellac/stearic acid emulsion on deacetylated konjac glucomannan films (dKGM). The effect of stearic acid content on structure and properties of the coated films were investigated by field emission scanning electron microscopy (FE SEM), Fourier transform infrared spectroscopy (FT-IR), ultraviolet spectroscopy (UV), water vapor permeability (WVP), water uptake, water contact angle, and tensile testing. The results revealed that shellac in the coating adhered intimately to the surface of dKGM film, and provided a substrate for the dispersion of stearic acid which played an important role in enhancement of the moisture barrier properties and mechanical properties of the coated films. The WVP of the coated films decreased from 2.63×10(-11) to 0.37×10(-11)g/(msPa) and the water contact angle increased from 68° to 101.2° when stearic acid content increased from 0wt% to 40wt%, showing the potential applications in food preservation. PMID:25542116

  11. Insulin resistance is associated with altered amino acid metabolism and adipose tissue dysfunction in normoglycemic women

    OpenAIRE

    Petri Wiklund; Xiaobo Zhang; Satu Pekkala; Reija Autio; Lingjia Kong; Yifan Yang; Sirkka Keinänen-Kiukaanniemi; Markku Alen; Sulin Cheng

    2016-01-01

    Insulin resistance is associated adiposity, but the mechanisms are not fully understood. In this study, we aimed to identify early metabolic alterations associated with insulin resistance in normoglycemic women with varying degree of adiposity. One-hundred and ten young and middle-aged women were divided into low and high IR groups based on their median HOMA-IR (0.9 ± 0.4 vs. 2.8 ± 1.2). Body composition was assessed using DXA, skeletal muscle and liver fat by proton magnetic resonance spectr...

  12. Modeling the combined effects of pH, temperature and ascorbic acid concentration on the heat resistance of Alicyclobacillus acidoterrestis.

    Science.gov (United States)

    Bahçeci, K Savaş; Acar, Jale

    2007-12-15

    In this study, thermal inactivation parameters (D- and z-values) of Alicyclobacillus acidoterrestris spores in McIlvaine buffers at different pH, apple juice and apple nectar produced with and without ascorbic acid addition were determined. The effects of pH, temperature and ascorbic acid concentration on D-values of A. acidoterrestris spores were also investigated using response surface methodology. A second order polynomial equation was used to describe the relationship between pH, temperature, ascorbic acid concentration and the D-values of A. acidoterrestris spores. Temperature was the most important factor on D-values, and its effect was three times higher than those of pH. Although the statistically significant, heat resistance of A. acidoterrestris spores was not so influenced from the ascorbic acid within the concentration studied. D-values in apple juice and apple nectars were higher than those in buffers as heating medium at similar pH. The D-values ranged from 11.1 (90 degrees C) to 0.7 min (100 degrees C) in apple juice, 14.1 (90 degrees C) to 1.0 min (100 degrees C) in apple nectar produced with ascorbic acid addition, and 14.4 (90 degrees C) to 1.2 min (100 degrees C) in apple nectar produced without ascorbic acid addition. However, no significant difference in z-values was observed among spores in the juices and buffers at different pH, and it was between 8.2 and 9.2 degrees C. The results indicated that the spores of A. acidoterrestris may survive in fruit juices and nectars after pasteurization treatment commonly applied in the food industry.

  13. Molecular Characterization of Intrinsic and Acquired antibiotic resistance in lactic Acid bacteria and Bifidobacteria

    NARCIS (Netherlands)

    Ammor, M.S.; Flórez, A.B.; Hoek, van A.H.A.M.; Reyes-Gavilan, de los C.G.; Aarts, H.J.M.; Margolles, A.; Mayo, B.

    2008-01-01

    The minimum inhibitory concentrations (MICs) of 6 different antibiotics (chloramphenicol, clindamycin, erythromycin, streptomycin, tetracycline and vancomycin) were determined for 143 strains of lactic acid bacteria and bifidobacteria using the Etest. Different MICs were found for different species

  14. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Carlos, E-mail: carllosmendez@gmail.com; Esquerre, Karla, E-mail: karlaesquerre@ufba.br; Matos Queiroz, Luciano, E-mail: lmqueiroz@ufba.br

    2015-01-15

    Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

  15. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    Science.gov (United States)

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. PMID:27372134

  16. Two-phase anaerobic digestion of coffee wet wastewater: Effect of recycle on anaerobic process performance

    Directory of Open Access Journals (Sweden)

    Yans Guardia Puebla

    2014-01-01

    Full Text Available The present work shows the results of the two-phase anaerobic digestion assessment for the treatment of coffee wet wastewater. The effect of recycle on the anaerobic digestion process was studied. Twooverall organic loading rate (OLR values of 4,2 and 5,7 kgCOD·m -3 ·d -1 , with same overall hydraulic retention time (HRT of 21,5 h was evaluated.In a two-phase system wereapplied two recycle rate of 0,4 and 1,0, of the effluent of an UASB-UAF methanogenic hybrid reactor towards an UASB acidogenic reactor. In the anaerobic system with a recycle rate of 1,0 the total chemical oxygen demand (COD removal was 90%. The introduction of the recycle decreased the concentration of total volatile fatty acids (VFA, but it did not affect their composition, suggesting that the degradation pattern did not change. The presence of the acidogenic reactor in the two-phase system improved the stability of the anaerobic digestion process and increased the efficiency of methanogenic digester.

  17. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    Science.gov (United States)

    Hassan, Siti; Dahlan, Irvan

    2013-09-01

    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  18. Role of Antioxidant Enzymes in Bacterial Resistance to Organic Acids

    OpenAIRE

    Bruno-Bárcena, Jose M.; Azcárate-Peril, M. Andrea; Hassan, Hosni M.

    2010-01-01

    Growth in aerobic environments has been shown to generate reactive oxygen species (ROS) and to cause oxidative stress in most organisms. Antioxidant enzymes (i.e., superoxide dismutases and hydroperoxidases) and DNA repair mechanisms provide protection against ROS. Acid stress has been shown to be associated with the induction of Mn superoxide dismutase (MnSOD) in Lactococcus lactis and Staphylococcus aureus. However, the relationship between acid stress and oxidative stress is not well under...

  19. Acid resistant lipase as replacement therapy in chronic pancreatic exocrine insufficiency: a study in dogs.

    OpenAIRE

    S. M. Griffin; Alderson, D.; Farndon, J R

    1989-01-01

    Conventional treatment of pancreatic steatorrhoea in man has been unsatisfactory because 90% of the lipase content of therapy is inactivated by acid in the stomach and large doses of replacement treatment are needed to provide adequate supplementation. An acid stable agent (fungal lipase) was investigated in the treatment of pancreatic deficiency steatorrhoea in 11 pancreatectomised dogs maintained on a fixed dietary intake of fat and treated with pancreatin or fungal lipase. Ten grams (60,00...

  20. Fatty acid nitroalkenes induce resistance to ischemic cardiac injury by modulating mitochondrial respiration at complex II

    OpenAIRE

    Koenitzer, Jeffrey R; Gustavo Bonacci; Woodcock, Steven R.; Chen-Shan Chen; Nadiezhda Cantu-Medellin; Kelley, Eric E.; Schopfer, Francisco J.

    2016-01-01

    Nitro-fatty acids (NO2-FA) are metabolic and inflammatory-derived electrophiles that mediate pleiotropic signaling actions. It was hypothesized that NO2-FA would impact mitochondrial redox reactions to induce tissue-protective metabolic shifts in cells. Nitro-oleic acid (OA-NO2) reversibly inhibited complex II-linked respiration in isolated rat heart mitochondria in a pH-dependent manner and suppressed superoxide formation. Nitroalkylation of Fp subunit was determined by BME capture and the s...