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. METRONIDAZOLE RESISTANCE IN ANAEROBES ISOLATED FROM CHRONIC PERIODONTITIS CASES

    Directory of Open Access Journals (Sweden)

    Sushma Narayan

    2016-01-01

    Full Text Available Periodontitis is the most frequent oral health problem in the world. The infection is primarily caused by anaerobic microorganisms. Metronidazole is the most commonly used drug to treat the infection but recently the anaerobes have shown the resistance to this drug. Therefore, the present study was undertaken to isolate and identify the anaerobes associated with periodontitis and study their susceptibility pattern to the Metronidazole. Total 90 samples were collected from chronic periodontitis cases. Anaerobes were isolated in 71% of periodontitis cases. Gram positive organisms were more predominantly isolated than Gram negative organisms. The Gram negative anaerobes were found to be 100% sensitive to Metronidazole while Gram positive anaerobes showed 8% resistance to Metronidazole.

  5. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures.

    Science.gov (United States)

    Oliver, Christy E; Beier, Ross C; Hume, Michael E; Horrocks, Shane M; Casey, Thomas A; Caton, Joel S; Nisbet, David J; Smith, David J; Krueger, Nathan A; Anderson, Robin C

    2010-04-01

    Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by

  6. Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment.

    Science.gov (United States)

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Yuan, Zhiguo

    2016-05-01

    In some wastewater treatment plants (WWTPs), the ever increasing production of sludge with the expanding population overloaded the anaerobic digestion which compromises the sludge reduction efficiency. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, to a very limited extent. This study verified the effectiveness of free nitrous acid (FNA i.e. HNO2) pre-treatment on enhancing full-scale ADS degradation in post anaerobic digestion. The ADS collected from a full-scale WWTP was subject to FNA treatment at concentrations of 0.77, 1.54, 2.31, 3.08, and 3.85 mg N/L for 24 h followed by biochemical methane potential tests. The FNA treatment at all concentrations resulted in an increase (from 1.5-3.1 % compared to the control) in sludge reduction with the highest improvement achieved at 0.77 mg HNO2-N/L. The FNA treatment at this concentration also resulted in the highest increase in methane production (40 %) compared to the control. The economic analysis indicates that FNA treatment is economically attractive for enhancing post anaerobic digestion of full-scale ADS.

  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. 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

    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...... 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...... and the history of the reactor process. It should be pointed out that the observed dynamics of VFA responses were based on hourly measurements, meaning that the response duration was much lower than the hydraulic retention time, which exceeds several days in anaerobic CSTR systems....

  10. 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...... concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities and VFA levels from 1 to 30 mM (0.04 to 8.50 mA/m2, R2=0.97) and then from 30 to 200 mM (8.50 to 10.80 mA/m2, R2=0.95). The detection range was much broader than that of other existing...... and reliable measurement of VFA levels during AD and other anaerobic processes....

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

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Jin, Xiangdan; Angelidaki, Irini

    2015-01-01

    Due to increasing environmental concerns of using fossil fuels and decreasing in their reserves, the promotion of renewable energy technologies is crucial. Anaerobic digestion (AD), a well-developed technology converting organic waste into biogas, is gaining increased attention in recent years...... 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...

  12. 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).

  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. 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.

  15. Resistance to freshwater exposure in White Sea Littorina spp. I: Anaerobic metabolism and energetics.

    Science.gov (United States)

    Sokolova, I M; Bock, C; Pörtner, H O

    2000-03-01

    Anaerobic metabolism and changes in the osmotic concentration of extravisceral fluid were studied in the White Sea periwinkles (Littorina littorea, Littorina saxatilis and Littorina obtusata) during freshwater exposure. Resistance to hypoosmotic stress increased in the order: L. obtusata Littorina spp. to extreme hypoosmotic stress may be related to their different abilities to reduce metabolic rate and ATP turnover during sustained anoxia. Species-specific variations in anaerobic capacity of Littorina spp. are discussed in relation to their vertical distribution, size and ecology.

  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. 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; 李建政; 赵丹; 陈晓蕾

    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.

  19. Acid resistance of starch granules

    Energy Technology Data Exchange (ETDEWEB)

    Nara, S.; Sakakura, M.; Komiya, T.

    1983-08-01

    When potato starch was hydrolyzed to form Naegeli amylodextrin by 16% sulfuric acid at 30/sup 0/C, only the amorphous portion of the starch granules was deteriorated. The crystallinity of Naegeli amylodextrin showing the hydrolysis ratio of 0.22 was 1.28 times as large as that of original starch. The hydrolysis process at above 45/sup 0/C was given by two exponential equations. The value of acid resistance portion (C/sub 0/) at 30 and 38/sup 0/C was 100%, while the values at 45, 50 and 55/sup 0/C were 67, 38 and 18%, respectively. The high value of C/sub 0/ generally showed the high acid resistance in the various starches. Sweet potato and waxy rice starches were more easily hydrolysed than other starches, although they gave the relatively high value of C/sub 0/. Thus, it was slightly more difficult for low acid resistance portion of potato starch to be hydrolyzed than for that of other starches. Moreover, that of waxy rice was easily hydrolyzed.

  20. 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.

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

    Science.gov (United States)

    Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2012-04-01

    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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Effect of dietary arsonic acids on performance characteristics of swine waste anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Brumm, M.C.; Sutton, A.L.; Jones, D.D.

    1980-01-01

    A completely random design experiment was conducted to determine the effect of dietary arsonic acids on the performance of laboratory swine waste anaerobic digesters. Fortified corn-soybean meal diets containing no arsonic acids (control), 100 ppm arsanilic acid or 75 ppm roxarsone were fed to growing-finishing pigs. Fresh waste (including urine) from all treatments were collected daily for 74 days and loaded at a rate of 2.4 kg volatile solids/cubic meter into nine 25-L anaerobic digesters heated to 34 degrees with continuous agitation and total gas collection. After a 60-day acclimation period, daily gas production and composition and nutrient composition data were obtained from the anaerobic digesters. Inclusion of the arsonic acids in swine diets reduced dry matter and volatile solids content. Dietary arsonic acids also increased NH4+-N. Alky. was high in all the digesters; however, arsonic acids decreased alky. Dietary arsonic acids reduced the ratio of CH4 to CO2 in the gas compared to the control. Significant amounts of As accumulated in the digesters. Alcohol, ethanol, and propanol concentrations were increased by roxarsone, and arsanilic acid increased the PrCO2H concentrations over the percentage in both the roxarsone and control digesters.

  7. The impacts of triclosan on anaerobic community structures, function, and antimicrobial resistance.

    Science.gov (United States)

    McNamara, Patrick J; LaPara, Timothy M; Novak, Paige J

    2014-07-01

    Triclosan is a widespread antimicrobial agent that accumulates in anaerobic digesters used to treat the residual solids generated at municipal wastewater treatment plants; there is very little information, however, about how triclosan impacts microbial communities in anaerobic digesters. We investigated how triclosan impacts the community structure, function and antimicrobial resistance genes in lab-scale anaerobic digesters. Previously exposed (to triclosan) communities were amended with 5, 50, and 500 mg/kg of triclosan, corresponding to the median, 95th percentile, and 4-fold higher than maximum triclosan concentration that has been detected in U.S. biosolids. Triclosan amendment caused all of the Bacteria and Archaea communities to structurally diverge from that of the control cultures (based on ARISA). At the end of the experiment, all triclosan-amended Archaea communities had diverged from the control communities, regardless of the triclosan concentration added. In contrast, over time the Bacteria communities that were amended with lower concentrations of triclosan (5 mg/kg and 50 mg/kg) initially diverged and then reconverged with the control community structure. Methane production at 500 mg/kg was nearly half the methane production in control cultures. At 50 mg/kg, a large variability in methane production was observed, suggesting that 50 mg/kg may be a tipping point where function begins to fail in some communities. When previously unexposed communities were exposed to 500 mg triclosan/kg, function was maintained, but the abundance of a gene encoding for triclosan resistance (mexB) increased. This research suggests that triclosan could inhibit methane production in anaerobic digesters if concentrations were to increase and may also select for resistant Bacteria. In both cases, microbial community composition and exposure history alter the influence of triclosan.

  8. 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

    in enrichment cultures degrading phthalic acid esters under methanogenic conditions. A selection pressure was applied by adding DBP at 10 and 200 mg L(-1) in semi-continuous anaerobic reactors. The microbial dynamics were monitored using single strand conformation polymorphism (SSCP). While only limited abiotic...

  9. 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.

  10. Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene

    Science.gov (United States)

    Bradley, P.M.; Chapelle, F.H.; Lovley, D.R.

    1998-01-01

    Anaerobic oxidation of [1,2-14C]vinyl chloride and [1,2- 14C]dichloroethene to 14CO2 under humic acid-reducing conditions was demonstrated. The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought.

  11. Effect of humic acid in leachate on specific methanogenic activity of anaerobic granular sludge.

    Science.gov (United States)

    Guo, Mengfei; Xian, Ping; Yang, Longhui; Liu, Xi; Zhan, Longhui; Bu, Guanghui

    2015-01-01

    In order to find out the effects of humic acid (HA) in anaerobic-treated landfill leachate on granular sludge, the anaerobic biodegradability of HA as well as the influences of HA on the total cumulative methane production, the anaerobic methanization process and the specific methanogenic activity (SMA) of granular sludge are studied in this paper. Experimental results show that as a non-biodegradable organic pollutant, HA is also difficult to be decomposed by microbes in the anaerobic reaction process. Presence of HA and changes in the concentration have no significant influences on the total cumulative methane production and the anaerobic methanization process of granular sludge. Besides, the total cumulative methane production cannot reflect the inhibition of toxics on the methanogenic activity of granular sludge on the premise of sufficient reaction time. Results also show that HA plays a promoting role on SMA of granular sludge. Without buffering agent the SMA value increased by 19.2% on average due to the buffering and regulating ability of HA, while with buffering agent the SMA value increased by 5.4% on average due to the retaining effect of HA on the morphology of the sludge particles. However, in the presence of leachate the SMA value decreased by 27.6% on average, because the toxic effect of the toxics in the leachate on granular sludge is much larger than the promoting effect of HA.

  12. 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

    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 ...

  13. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale mu

  14. Anaerobic biodegradation of oleic and palmitic acids: evidence of mass transfer limitations caused by long chain fatty acid accumulation onto the anaerobic sludge.

    Science.gov (United States)

    Pereira, M A; Pires, O C; Mota, M; Alves, M M

    2005-10-05

    Palmitic acid was the main long chain fatty acids (LCFA) that accumulated onto the anaerobic sludge when oleic acid was fed to an EGSB reactor. The conversion between oleic and palmitic acid was linked to the biological activity. When palmitic acid was fed to an EGSB reactor it represented also the main LCFA that accumulated onto the sludge. The way of palmitic acid accumulation was different in the oleic and in the palmitic acid fed reactors. When oleic acid was fed, the biomass-associated LCFA (83% as palmitic acid) were mainly adsorbed and entrapped in the sludge that became "encapsulated" by an LCFA layer. However, when palmitic acid was fed, the biomass-associated LCFA (the totality as palmitic acid) was mainly precipitated in white spots like precipitates in between the sludge, which remained "non-encapsulated." The two sludges were compared in terms of the specific methanogenic activity (SMA) in the presence of acetate, propionate, butyrate, and H(2)CO(2), before and after the mineralization of similar amounts of biomass-associated LCFA (4.6 and 5.2 g COD-LCFA/g of volatile suspended solids (VSS), for the oleic and palmitic acid fed sludge, respectively). The "non-encapsulated," sludge exhibited a considerable initial methanogenic activity on all the tested substrates, with the single exception of butyrate. However, with the "encapsulated" sludge only methane production from ethanol and H(2)/CO(2) was detected, after a lag phase of about 50 h. After mineralization of the biomass-associated LCFA, both sludges exhibited activities of similar order of magnitude in the presence of the same individual substrates and significantly higher than before. The results evidenced that LCFA accumulation onto the sludge can create a physical barrier and hinder the transfer of substrates and products, inducing a delay on the initial methane production. Whatever the mechanism, metabolic or physical, that is behind this inhibition, it is reversible, being eliminated after the

  15. Anaerobic Fermentation for Production of Carboxylic Acids as Bulk Chemicals from Renewable Biomass.

    Science.gov (United States)

    Wang, Jufang; Lin, Meng; Xu, Mengmeng; Yang, Shang-Tian

    Biomass represents an abundant carbon-neutral renewable resource which can be converted to bulk chemicals to replace petrochemicals. Carboxylic acids have wide applications in the chemical, food, and pharmaceutical industries. This chapter provides an overview of recent advances and challenges in the industrial production of various types of carboxylic acids, including short-chain fatty acids (acetic, propionic, butyric), hydroxy acids (lactic, 3-hydroxypropionic), dicarboxylic acids (succinic, malic, fumaric, itaconic, adipic, muconic, glucaric), and others (acrylic, citric, gluconic, pyruvic) by anaerobic fermentation. For economic production of these carboxylic acids as bulk chemicals, the fermentation process must have a sufficiently high product titer, productivity and yield, and low impurity acid byproducts to compete with their petrochemical counterparts. System metabolic engineering offers the tools needed to develop novel strains that can meet these process requirements for converting biomass feedstock to the desirable product.

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

    OpenAIRE

    Flotats Ripoll, Xavier

    2013-01-01

    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) a...

  18. Modeling anaerobic digestion of blue algae: stoichiometric coefficients of amino acids acidogenesis and thermodynamics analysis.

    Science.gov (United States)

    Yuan, Xian-Zheng; Shi, Xiao-Shuang; Yuan, Chun-Xin; Wang, Yu-Ping; Qiu, Yan-Ling; Guo, Rong-Bo; Wang, Li-Sheng

    2014-02-01

    In order to facilitate the application of Anaerobic Digestion Model No. 1 (ADM1), an approach for a detailed calculation of stoichiometric coefficients for amino acids acidogenesis during the anaerobic digestion of blue algae is presented. The simulation results obtained support the approach by good predictions of the dynamic behavior of cumulative methane production, pH values as well as the concentrations of acetate, propionate, butyrate, valerate and inorganic nitrogen. The sensitivity analysis based on Monte Carlo simulation showed that the stoichiometric coefficients for amino acids acidogenesis had high sensitivities to the outputs of the model. The model further indicated that the Gibbs free energies from the uptake of long-chain fatty acids (LCFA), valerate and butyrate were positive through the digestion, while the free energies for other components were negative. During the digestion, the cumulative heat productions from microbial activities and methane were 77.69 kJ and 185.76 kJ, respectively. This result suggested that proper heat preservation of anaerobic digesters could minimize the external heating needs due to the heat produced from microbial activities.

  19. Anaerobic degradation of purified terephthalic acid wastewater using a novel, rapid mass-transfer circulating fluidized bed.

    Science.gov (United States)

    Feng, Yangyang; Lu, Beibei; Jiang, Yu; Chen, Yinwen; Shen, Shubao

    2012-01-01

    The anaerobic treatability of purified terephthalic acid (PTA) wastewater in a novel, rapid mass-transfer fluidized bed reactor using brick particles as porous carrier materials was investigated. The reactor operation was stable after a short 34 day start-up period, with chemical oxygen demand (COD) removal efficiency between 65 and 75%, terephthalate (TA) removal efficiency between 60% and 70%, and system organic loading rate (OLR) increasing from 7.37 to 18.52 kg COD/m(3) d. The results demonstrate that the reactor is very efficient, and requires a low hydraulic retention time (HRT) of 8 h to remove both TA and COD from the high-concentration PTA wastewater. The system also has high resistance capacity to varied OLR.

  20. 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.

  1. Nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria with C2/C3 fatty acid in upflow anaerobic sludge blanket reactors.

    Science.gov (United States)

    Liang, Yuhai; Li, Dong; Zhang, Xiaojing; Zeng, Huiping; Yang, Yin; Zhang, Jie

    2015-10-01

    In anaerobic ammonium oxidation (Anammox) process, a harsh ratio of nitrite to ammonia in influent was demanded, and the max nitrogen removal efficiency could only achieve to 89%, both of which limited the development of Anammox. The aim of this work was to study the nitrate removal by organotrophic anaerobic ammonium oxidizing bacteria (AAOB) with C2/C3 fatty acid in upflow anaerobic sludge blanket (UASB) reactors. In this study, organotrophic AAOB was successfully enriched by adding acetate and propionate with the total organic carbon to nitrogen (TOC/N) ratio of 0.1. In the condition of low substrate, the TN removal efficiency reached 90%, with the effluent TN of around 11.8 mg L(-1). After the addition of acetate and propionate, the predominant species in Anammox granular sludge transformed to Candidatus Jettenia that belonging to organotrophic AAOB from the Candidatus Kuenenia relating to general AAOB.

  2. Progress in engineering acid stress resistance of lactic acid bacteria.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-02-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of fermented foods, and are considered as probiotic due to their health-promoting effect. However, LAB encounter various environmental stresses both in industrial fermentation and application, among which acid stress is one of the most important survival challenges. Improving the acid stress resistance may contribute to the application and function of probiotic action to the host. Recently, the advent of genomics, functional genomics and high-throughput technologies have allowed for the understanding of acid tolerance mechanisms at a systems level, and many method to improve acid tolerance have been developed. This review describes the current progress in engineering acid stress resistance of LAB. Special emphasis is placed on engineering cellular microenvironment (engineering amino acid metabolism, introduction of exogenous biosynthetic capacity, and overproduction of stress response proteins) and maintaining cell membrane functionality. Moreover, strategies to improve acid tolerance and the related physiological mechanisms are also discussed.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  9. Neutral fat hydrolysis and long-chain fatty acid oxidation during anaerobic digestion of slaughterhouse wastewater.

    Science.gov (United States)

    Masse, L; Massé, D I; Kennedy, K J; Chou, S P

    2002-07-05

    Neutral fat hydrolysis and long-chain fatty acid (LCFA) oxidation rates were determined during the digestion of slaughterhouse wastewater in anaerobic sequencing batch reactors operated at 25 degrees C. The experimental substrate consisted of filtered slaughterhouse wastewater supplemented with pork fat particles at various average initial sizes (D(in)) ranging from 60 to 450 microm. At the D(in) tested, there was no significant particle size effect on the first-order hydrolysis rate. The neutral fat hydrolysis rate averaged 0.63 +/- 0.07 d(-1). LCFA oxidation rate was modelled using a Monod-type equation. The maximum substrate utilization rate (kmax) and the half-saturation concentration (Ks) averaged 164 +/- 37 mg LCFA/L/d and 35 +/- 31 mg LCFA/L, respectively. Pork fat particle degradation was mainly controlled by LCFA oxidation rate and, to a lesser extent, by neutral fat hydrolysis rate. Hydrolysis pretreatment of fat-containing wastewaters and sludges should not substantially accelerate their anaerobic treatment. At a D(in) of 450 microm, fat particles were found to inhibit methane production during the initial 20 h of digestion. Inhibition of methane production in the early phase of digestion was the only significant effect of fat particle size on anaerobic digestion of pork slaughterhouse wastewater. Soluble COD could not be used to determine the rate of lipid hydrolysis due to LCFA adsorption on the biomass.

  10. 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.

  11. 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

    innovatively which was separated from the anode chamber by an anion exchange membrane. The detection range can be broadened as only part of the ionized VFAs can transport through the membrane and the biofilm can be protected from inhibitors and toxicants. The correlation between current densities and VFA......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 bulk substrate was dosed into the middle chamber...

  12. Bio-electrolytic sensor for rapid monitoring of volatile fatty acids in anaerobic digestion process

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Li, Xiaohu; Zhao, Nannan;

    2017-01-01

    This study presents an innovative biosensor that was developed on the basis of a microbial electrolysis cell for fast and reliable measurement of volatile fatty acids (VFA) during anaerobic digestion (AD) process. The bio-electrolytic sensor was first tested with synthetic wastewater containing...... to monitor VFA concentrations in a lab-scale AD reactor for a month. The VFA measurements from the sensor correlated well with those from GC analysis which proved the accuracy of the system. Since hydrogen was produced in the cathode as byproduct during monitoring, the system could be energy self...

  13. 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.

  14. 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

    2016-07-22

    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.

  15. Development of antimicrobial resistance in the normal anaerobic microbiota during one year after administration of clindamycin or ciprofloxacin.

    Science.gov (United States)

    Rashid, Mamun-Ur; Weintraub, Andrej; Nord, Carl Erik

    2015-02-01

    Thirty healthy subjects (15 males and 15 females) were randomly assigned in three groups and clindamycin (150 mg qid) or ciprofloxacin (500 mg bid) or placebo was given for a 10-day period. Skin, nasal, saliva, faeces samples were collected at day - 1, day 11, 1 month, 2 months, 4 months and 12 months post administration for microbiological analysis. Ciprofloxacin or clindamycin had no impact on the anaerobic skin microbiota and the proportions of antibiotic resistant anaerobic bacteria were similar as in the placebo group. Ciprofloxacin had impact on the Propionibacterium acnes in the nasal microbiota that normalized after 1 month, however, ciprofloxacin-resistant P. acnes strains increased at month 2 and month 12. Clindamycin had no impact on the nasal microbiota. In the oropharyngeal microbiota, a higher proportion of ciprofloxacin resistant Veillonella was found, it lasting up to 12 months post dosing. In the clindamycin group, clindamycin-resistant Prevotella spp. were found in increased proportions compared to placebo at various time points except month 4 in the saliva samples. The relative proportion of ciprofloxacin-resistant Bifidobacteria increased in the faecal samples on day 11, 1 month, 4 months and 12 months post dosing compared to placebo. The proportion of clindamycin-resistant Bacteroides spp. increased at 1, 2, 4 and 12 months post dosing compared to placebo in the faecal samples. No Clostridium difficile was recovered from any of the samples from any of the volunteers at any visit. The concentrations of ciprofloxacin or clindamycin in the faeces were higher than the MICs for most of the organisms present in the normal microbiota. No obvious correlation between the groups in resistant patterns for anaerobic bacteria was observed. In conclusion, based on the microbiological data of the microbiota as well as the results of the bioassays for ciprofloxacin and clindamycin concentrations in the faecal samples, oral administration of ciprofloxacin

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

    Science.gov (United States)

    Liu, Siqing; Bischoff, Kenneth M; Leathers, Timothy D; Qureshi, Nasib; Rich, Joseph O; Hughes, Stephen R

    2013-09-01

    A novel Clostridium tyrobutyricum 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), corn stover (CSH), rice hull (RHH), and switchgrass (SGH). Results indicated that 50% WSH with a Clostridia medium (Ct) produced the most butyric acid (8.06 g L(-1), 0.46 g/g glucose), followed by 50% SGH with Ct (6.01 g L(-1), 0.44 g/g glucose), however, 50% CSH Ct showed growth inhibition. RPT-4213 was then used in pH-controlled bioreactor fermentations using 60% WSH and SGH, with a dilute (0.5×) Ct medium, resulting 9.87 g L(-1) butyric acid in WSH (yield 0.44 g/g) and 7.05 g L(-1) butyric acid in SGH (yield 0.42 g/g). The titer and productivity could be improved through process engineering.

  18. 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.

  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. 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.

  1. Distribution of antibiotic resistance genes (ARGs) in anaerobic digestion and land application of swine wastewater.

    Science.gov (United States)

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

    2016-06-01

    Swine farm and the adjacent farmland are hot spots of ARGs. However, few studies have investigated the on-site occurrence of ARGs distributed in the process of anaerobic digestion (AD) followed by land application of swine wastewater. Two typical swine farms, in southern and northern China respectively, with AD along with land application were explored on ARG distributions. ARGs were highly abundant in raw swine wastewater, AD effectively reduced the copy number of all detected ARGs (0.21-1.34 logs removal), but the relative abundance with different resistance mechanisms showed distinctive variation trends. The reduction efficiency of ARGs was improved by stable operational temperature and longer solid retention time (SRT) of AD. ARGs in soil characterized the contamination from the irrigation of the digested liquor. The total ARGs quantity in soil fell down by 1.66 logs in idle period of winter compared to application period of summer in the northern region, whereas the total amount was steady with whole-year application in south. Some persistent (sul1 and sul2) and elevated ARGs (tetG and ereA) in AD and land application need more attention.

  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. Influence of volatile fatty acid concentration stability on anaerobic degradation of linear alkylbenzene sulfonate.

    Science.gov (United States)

    Okada, Dagoberto Y; Delforno, Tiago P; Esteves, Andressa S; Polizel, Juliana; Hirasawa, Julia S; Duarte, Iolanda C S; Varesche, Maria B A

    2013-10-15

    Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is usually found in wastewaters. Despite the greater LAS removal rate related to a lower concentrations of volatile fatty acids (VFA), the influence of different ranges of VFA on LAS degradation is not known. LAS degradation was evaluated in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors at different ranges of VFA concentrations. The reactors were fed with a synthetic wastewater containing LAS (14 mg/L). A greater LAS removal rate (40-80%) was related to the lower and narrower range of acetic acid concentration (1-22 mg/L) in the EGSB reactor. In the UASB reactor, the acetic acid concentrations presented a wider range (2-45 mg/L), and some low LAS removal rates (around 20-25%) were observed even at low acetic acid concentrations (<10 mg/L). The high recirculation rate in the EGSB reactor improved substrate-biomass contact, which resulted in a narrower range of VFA and greater LAS removal rate.

  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. 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.

  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. 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.

  8. Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge.

    Science.gov (United States)

    Appels, Lise; Van Assche, Ado; Willems, Kris; Degrève, Jan; Van Impe, Jan; Dewil, Raf

    2011-03-01

    Anaerobic digestion is generally considered to be an economic and environmentally friendly technology for treating waste activated sludge, but has some limitations, such as the time it takes for the sludge to be digested and also the ineffectiveness of degrading the solids. Various pre-treatment technologies have been suggested to overcome these limitations and to improve the biogas production rate by enhancing the hydrolysis of organic matter. This paper studies the use of peracetic acid for disintegrating sludge as a pre-treatment of anaerobic digestion. It has been proved that this treatment effectively leads to a solubilisation of organic material. A maximum increase in biogas production by 21% is achieved. High dosages of PAA lead to a decrease in biogas production. This is due to the inhibition of the anaerobic micro-organisms by the high VFA-concentrations. The evolution of the various VFAs during digestion is studied and the observed trends support this hypothesis.

  9. 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.

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

    OpenAIRE

    Contrera,R. C.; K. C. da Cruz Silva; G. H. Ribeiro Silva; D. M. Morita; Zaiat,M.; V. Schalch

    2015-01-01

    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 ...

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

    NARCIS (Netherlands)

    Elferink, SJWHO; Krooneman, J; Gottschal, JC; Spoelstra, SF; 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

  12. Volatile fatty acid degradation kinetics in anaerobic process; Cinetica de la degradacion de acidos grasos volatiles en procesos anaerobios

    Energy Technology Data Exchange (ETDEWEB)

    Riscado, S.; Osuna, B.; Iza, J.; Ruiz, E. [Universidad del Pais Vasco. Bilbao (Spain)

    1998-10-01

    While searching for the optimal substrate load for anaerobic toxicity assays, the inhibition caused by the propionic acid has been addressed. Lab scale experiments have been carried out to assess the effects of different loads and acid ratios. Results bad been subjected to kinetic analysis and show the degradation follows a first order kinetic, and acetic is easier to degrade than propionic acid. The optimal load for a 100 ml vial assay is composed of 158 mg COD of the 3:1:1 HAc:HPr:HBu mixture. (Author) 9 refs.

  13. 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.

  14. Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jong, T.; Parry, D.L. [Charles Darwin University, Darwin, NT (Australia). Faculty for Educational Health & Science

    2006-07-15

    The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l{sup -1} lactate. Sulfate reduction rates of 553-1052 mmol m{sup -3} d{sup -1} were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min{sup -1}. When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m{sup -3} d{sup -1} after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters.

  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. Fatty Acids, Obesity and Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Peter Arner

    2015-04-01

    Full Text Available Objective: Although elevated free fatty acid (FFA levels in obesity have been considered to be of importance for insulin resistance, a recent meta-analysis suggested normal FFA levels in obese subjects. We investigated fasting circulating FFA and glycerol levels in a large cohort of non-obese and obese subjects. Methods: Subjects recruited for a study on obesity genetics were investigated in the morning after an overnight fast (n = 3,888. Serum FFA (n = 3,306, plasma glycerol (n = 3,776, and insulin sensitivity index (HOMA-IR,n = 3,469 were determined. Obesity was defined as BMI ≥ 30 kg/m2 and insulin resistance as HOMA-IR ≥ 2.21. Results: In obese subjects, circulating FFA and glycerol levels were higher than in non-obese individuals (by 26% and 47%, respectively; both p Conclusion: Circulating FFA and glycerol levels are markedly elevated in obesity but only marginally influenced by insulin resistance and type 2 diabetes. Whether these differences persist during diurnal variations in circulating FFA/glycerol, remains to be established.

  17. 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.

  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. Determination of some aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography with conductimetric detection on a weakly acidic cation-exchange resin column.

    Science.gov (United States)

    Ito, Kazuaki; Takayama, Yohichi; Ikedo, Mikaru; Mori, Masanobu; Taoda, Hiroshi; Xu, Qun; Hu, Wenzhi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2004-06-11

    The determination of seven aliphatic carboxylic acids, formic, acetic, propionic, isobutyric, n-butyric, isovaleric and n-valeric acids in anaerobic digestion process waters was examined using ion-exclusion chromatography with conductimetric detection. The analysis of these biologically important carboxylic acids is necessary as a measure for evaluating and controlling the process. The ion-exclusion chromatography system employed consisted of polymethacrylate-based weakly acidic cation-exchange resin columns (TSKgel OApak-A or TSKgel Super IC-A/C). weakly acidic eluent (benzoic acid), and conductimetric detection. Particle size and cation-exchange capacity were 5 microm and 0.1 meq./ml for TSKgel OApak-A and 3 microm and 0.2 meq./ml for TSKgel Super IC-A/C, respectively. A dilute eluent (1.0-2.0 mM) of benzoic acid was effective for the high resolution and highly conductimetric detection of the carboxylic acids. The good separation of isobutyric and n-butyric acids was performed using the TSKgel Super IC-A/C column (150 mm x 6.0 mm i.d. x 2). The simple and good chromatograms were obtained by the optimized ion-exclusion chromatography conditions for real samples from mesophilic anaerobic digestors, thus the aliphatic carboxylic acids were successfully determined without any interferences.

  20. 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.

  1. Robinsoniella peoriensis: A model anaerobic commensal bacterium for acquisition of antibiotic resistance?

    Science.gov (United States)

    Background: R. peoriensis was characterized in our laboratories from swine manure and feces as a Gram-positive, anaerobic bacterium. Since then strains of this species have been identified from a variety of mammalian and other gastrointestinal (GI) tracts, suggesting it is a member of the commensal ...

  2. 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...

  3. 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.

  4. [Regulating acid stress resistance of lactic acid bacteria--a review].

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-07-04

    As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

  5. Startup of anaerobic fluidized bed reactors with acetic acid as the substrate.

    Science.gov (United States)

    Hsu, Y; Shieh, W K

    1993-02-05

    The startup of anaerobic fluidized bed reactors, which use Manville R-633 beads as the growth support media, acetate enriched bacterial culture as the inoculum, and acetic acid as the sole substrate, is studied. Tow startup strategies are evaluated: one based on maximum and stable substrate utilization and another based on maximum substrate loading controlled by reactor pH. The startup process is characterized using a number of operational parameters.The reactors again excellent total organic carbon (TOC) removal (i.e., > 97% at a feed concentration of 5000 mg TOC/L) and stable methane production (i.e., 0.90 L CH(4)/g TOC, where TOC(r) is TOC removed) at a early stage of the startup process, regardless of the strategies applied. The loading can be increased rapidly without the danger of being overloaded. Significant losses of growth support media and biomass caused by gas effervescence at higher loadings limits the maximum loading that can be safely applied during startup process.A high reactor immobilized biomass inventory is achievable using the porous growth support media (e.g., Manville 633 beads). A rapid increase in loading creates a substrate rich environment that yields more viable reactor biomass. Both substrate utilization rate (batch and continuous) and immobilized biomass inventory stabilize concomitantly at the late stage of the startup process, indicating the attainment of steady-state conditions in reactors. Therefore, they are better parameters that TOC removal and methane production for characterizing the entire startup process of aerobic fluidized bed reactor.The strategy based on maximum substrate loading controlled by reactor pH significantly shortens the startup time. In this case, the reactor attains steady-state conditions approximately 140 days after startup. On the other hand, a startup time of 200 days is required when the strategy based maximum substrate utilization is adopted.

  6. Antibiotic resistance of Escherichia coli in leachates from municipal solid waste landfills: comparison between semi-aerobic and anaerobic operations.

    Science.gov (United States)

    Threedeach, Simanata; Chiemchaisri, Wilai; Watanabe, Toru; Chiemchaisri, Chart; Honda, Ryo; Yamamoto, Kazuo

    2012-06-01

    A bacterial susceptibility test to 31 antibiotics was conducted on the 80 isolated Escherichia coli from the leachates of the landfills in two different operations: semi-aerobic (SL) and anaerobic (AL) landfills. The average population of E. coli from SL and AL leachates were 2.2 × 10(4) and 9.4 × 10(3)CFU/100ml, respectively. Between 80.8% and 87.5% of the E. coli isolated from both leachates as resistant to the tested antibiotics and high resistances were found to doxycycline (53.8-68.8%), cephalothin (57.5-61.3%), tetracycline (51.3-67.5%) and minocycline (37.5-46.3%). The percentages of isolates resistant to most antibiotics were higher in the AL leachate. The exception was nitrofurantoin to which the isolates from the SL were highly resistant. E. coli from both sources showed similarly high susceptibilities (90-100%) to aminoglycosides, quinolones, chloramphenicol, sulfonamide and some new beta-lactams. The difference in available oxygen in landfills could affect E. coli susceptibility to antibiotics in leachates.

  7. 30 CFR 7.48 - Acid resistance test.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Acid resistance test. 7.48 Section 7.48 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.48 Acid resistance test....

  8. Influence of two-phase anaerobic digestion on fate of selected antibiotic resistance genes and class I integrons in municipal wastewater sludge

    DEFF Research Database (Denmark)

    Wu, Ying; Cui, Erping; Zuo, Yiru

    2016-01-01

    The response of representative antibiotic resistance genes (ARGs) to lab-scale two-phase (acidogenic/methanogenic phase) anaerobic digestion processes under thermophilic and mesophilic conditions was explored. The associated microbial communities and bacterial pathogens were characterized by 16S r...

  9. 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

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

    Science.gov (United States)

    Braun, Florence; Hamelin, Jérôme; Bonnafous, Anaïs; Delgenès, Nadine; Steyer, Jean-Philippe; Patureau, Dominique

    2015-01-01

    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 that PAH removal

  11. Analysis of proteins responsive to acetic acid in Acetobacter: molecular mechanisms conferring acetic acid resistance in acetic acid bacteria.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro

    2008-06-30

    Acetic acid bacteria are used for industrial vinegar production because of their remarkable ability to oxidize ethanol and high resistance to acetic acid. Although several molecular machineries responsible for acetic acid resistance in acetic acid bacteria have been reported, the entire mechanism that confers acetic acid resistance has not been completely understood. One of the promising methods to elucidate the entire mechanism is global analysis of proteins responsive to acetic acid by two-dimensional gel electrophoresis. Recently, two proteins whose production was greatly enhanced by acetic acid in Acetobacter aceti were identified to be aconitase and a putative ABC-transporter, respectively; furthermore, overexpression or disruption of the genes encoding these proteins affected acetic acid resistance in A. aceti, indicating that these proteins are involved in acetic acid resistance. Overexpression of each gene increased acetic acid resistance in Acetobacter, which resulted in an improvement in the productivity of acetic acid fermentation. Taken together, the results of the proteomic analysis and those of previous studies indicate that acetic acid resistance in acetic acid bacteria is conferred by several mechanisms. These findings also provide a clue to breed a strain having high resistance to acetic acid for vinegar fermentation.

  12. 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.

  13. 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.

  14. 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...

  15. Effect Of Imposed Anaerobic Conditions On Metals Release From Acid-Mine Drainage Contaminated Streambed Sediments

    Science.gov (United States)

    Remediation of streams influenced by mine-drainage may require removal and burial of metal-containing bed sediments. Burial of aerobic sediments into an anaerobic environment may release metals, such as through reductive dissolution of metal oxyhydroxides. Mining-impacted aerob...

  16. 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.

  17. 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.

  18. 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.

  19. Study of the anaerobic decomposition of valeric acid using variable stoichiometry and thermodynamic control

    OpenAIRE

    Fluvià Sabio, Sergi

    2014-01-01

    The stoichiometry of biological decomposition reactions of many organic compounds depends on the environmental conditions and the relative concentrations of reactants and products, making that, often the calculation models based on constant stoichiometric coefficients are not able to describe experimental values. This is the case of proteins in anaerobic medium, for which an effective and realistic method for expressing the dynamics of aminoacids reactions has not been found yet. A methodolog...

  20. Formic Acid: Development of an Analytical Method and Use as Process Indicator in Anaerobic Systems

    Science.gov (United States)

    1992-03-01

    proteins . First these organic constituents are hydrolyzed and liquified by extracellular enzymes into a soluble form that can pass through the bacterial...organic matter. Mackie and Bryant (1990) correlated the rate of protein synthesis with cell growth and substrate degradation. Their purpose was to mrnitor...when it was added to anaerobic systems, it was rapidly depleted; in most cases in a matter of minutes. In a study of whey waste, Chartrain and Zeikus

  1. Outer membrane mutants of Salmonella typhimurium LT2 have lipopolysaccharide-dependent resistance to the bactericidal activity of anaerobic human neutrophils.

    Science.gov (United States)

    Okamura, N; Spitznagel, J K

    1982-06-01

    The capacity of neutrophil polymorphonuclear granulocytes (PMNs) to phagocytize bacteria under anaerobic as well as aerobic conditions afforded the opportunity to compare the bactericidal activities of oxygen-independent and oxygen-dependent antimicrobial mechanisms in human PMNs challenged with Salmonella typhimurium LT2 and its lipopolysaccharide mutants (outer membrane mutants). Anaerobic human PMNs challenged with either opsonized LT2 or serum-treated zymosan failed to produce detectable superoxide anion (O2-) or to reduce nitroblue tetrazolium, although aerobic PMNs readily produced O2- in response to such challenge. Anaerobic PMNs killed these bacteria in an ordered fashion that appeared to be dependent on their lipopolysaccharide chemotype. As the carbohydrate content of the mutant lipopolysaccharide decreased, the bacteria became less resistant to the oxygen-independent bactericidal activity. The results resembled the ordered resistance to oxygen-independent killing observed with LT2 and its mutants in PMN-free systems with PMN granule proteins. Studies on the kinetics of killing showed these to be less rapid in anaerobic as compared with aerobic conditions. Opsonization increased the rate of phagocytosis, but such factors as opsonization and the rate of phagocytosis did not appear to affect intraleukocytic bactericidal capacity in that the resultant proportion of bacteria remaining viable after ingestion was similar regardless of which serum was used (normal serum, C6-deficient serum, C8-deficient serum, or no serum at all). The results are consistent with an active and substantial participation by oxygen-independent systems in the antimicrobial effects of neutrophils.

  2. Evaluating enhanced sulfate reduction and optimized volatile fatty acids (VFA) composition in anaerobic reactor by Fe (III) addition.

    Science.gov (United States)

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-17

    Anaerobic reactors with ferric iron addition have been experimentally demonstrated to be able to simultaneously improve sulfate reduction and organic matter degradation during sulfate-containing wastewater treatment. In this work, a mathematical model is developed to evaluate the impact of ferric iron addition on sulfate reduction and organic carbon removal as well as the volatile fatty acids (VFA) composition in anaerobic reactor. The model is successfully calibrated and validated using independent long-term experimental data sets from the anaerobic reactor with Fe (III) addition under different operational conditions. The model satisfactorily describes the sulfate reduction, organic carbon removal and VFA production. Results show Fe (III) addition induces the microbial reduction of Fe (III) by iron reducing bacteria (IRB), which significantly enhances sulfate reduction by sulfate reducing bacteria (SRB) and subsequently changes the VFA composition to acetate-dominating effluent. Simultaneously, the produced Fe (II) from IRB can alleviate the inhibition of undissociated H2S on microorganisms through iron sulfide precipitation, resulting in further improvement of the performance. In addition, the enhancement on reactor performance by Fe (III) is found to be more significantly favored at relatively low organic carbon/SO4(2-) ratio (e.g., 1.0) than at high organic carbon/SO4(2-) ratio (e.g., 4.5). The Fe (III)-based process of this work can be easily integrated with a commonly used strategy for phosphorus recovery, with the produced sulfide being recovered and then deposited into conventional chemical phosphorus removal sludge (FePO4) to achieve FeS precipitation for phosphorus recovery while the required Fe (III) being acquired from the waste ferric sludge of drinking water treatment process, to enable maximum resource recovery/reuse while achieving high-rate sulfate removal.

  3. 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...

  4. 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.

  5. 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.

  6. Recent investigations and updated criteria for the assessment of antibiotic resistance in food lactic acid bacteria.

    Science.gov (United States)

    Clementi, Francesca; Aquilanti, Lucia

    2011-12-01

    The worldwide use, and misuse, of antibiotics for about sixty years in the so-called antibiotic era, has been estimated in some one to ten million tons, a relevant part of which destined for non-therapeutic purposes such as growth promoting treatments for livestock or crop protection. As highly adaptable organisms, bacteria have reacted to this dramatic change in their environment by developing several well-known mechanisms of antibiotic resistance and are becoming increasingly resistant to conventional antibiotics. In recent years, commensal bacteria have become a cause of concern since they may act as reservoirs for the antibiotic resistance genes found in human pathogens. In particular, the food chain has been considered the main route for the introduction of animal and environment associated antibiotic resistant bacteria into the human gastrointestinal tract (GIT) where these genes may be transferred to pathogenic and opportunistic bacteria. As fundamental microbial communities in a large variety of fermented foods and feed, the anaerobe facultative, aerotolerant lactic acid bacteria (LAB) are likely to play a pivotal role in the resistance gene exchange occurring in the environment, food, feed and animal and human GIT. Therefore their antibiotic resistance features and their genetic basis have recently received increasing attention. The present article summarises the results of the latest studies on the most typical genera belonging to the low G + C branch of LAB. The evolution of the criteria established by European regulatory bodies to ensure a safe use of microorganisms in food and feed, including the assessment of their antibiotic resistance is also reviewed.

  7. 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.

  8. 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.

  9. Research progress on resistance of predominant periodontal anaerobes%牙周优势厌氧菌耐药性的研究进展

    Institute of Scientific and Technical Information of China (English)

    何俊霖

    2012-01-01

    Periodontal anaerobes are the main factors causing periodontitis. With the misuse of antibiotics in clinical treatment, the resistance of periodontal anaerobes is increasingly serious. In this review, we briefly dis-cribed periodontal anaerobic strains, discussed their mechanism of drug resistance and antibiotic sensitivity and analysis and detection of drug resistance genes. It was expected to provide scientific evidences for use of antimicrobial drugs and the development of new antimicrobial agents.%牙周厌氧菌是造成牙周炎的丰要因素.随着临床治疗中抗生素的滥用,牙周厌氧菌的耐约情况亦愈发普遍.本文就牙周优势厌氧菌及其耐药现状、耐药机制和耐药基因等研究进展作一综述,以期为临床合理使用抗菌药物和新抗菌药物的研发提供依据.

  10. Identification of sulfate reducers and Syntrophobacter sp. in anaerobic granular sludge by fatty-acid biomarkers and 16S rRNA probing

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.; Boschker, H.T.S.; Stams, A.J.M.

    1998-01-01

    The sulfate-reducing bacterial sludge population in anaerobic bioreactors, treating different types of wastewater in the presence or absence of sulfate, was evaluated by polar-lipid fatty acid (PLFA) analyses, and by 16S rRNA dot-blot hybridizations using specific 16S rRNA- targeted oligonucleotide

  11. Identification of sulfate reducers and Syntrophobacter sp. in anaerobic granular sludge by fatty-acid biomarkers and 16S rRNA probing

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.; Boschker, H.T.S.; Stams, A.J.M.

    1998-01-01

    The sulfate-reducing bacterial sludge population in anaerobic bioreactors, treating different types of wastewater in the presence or absence of sulfate, was evaluated by polar-lipid fatty acid (PLFA) analyses, and by 16S rRNA dot-blot hybridizations using specific 16S rRNA-targeted oligonucleotide p

  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

    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 communit...

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

    Science.gov (United States)

    Lindeboom, Ralph E F; Ferrer, Ivet; Weijma, Jan; van Lier, Jules B

    2013-12-01

    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 (0.6 L); feeding a concentration of acetate and VFA (1-10 g COD/L) corresponding to an expected pressure increase of 1-20 bar. The biogas composition improved with pressure up to 4.5 bar (>93% CH4), and stabilized at 10 and 20 bar. Both, acetotrophic and hydrogenotrophic methanogenic activity was observed. Substrate utilisation rates of 0.2, 0.1 and 0.1 g CODCH4/g VSS/d for acetate, propionate and butyrate were found to decrease by up to 50% with increasing final pressure. Most likely increased Na(+)-requirement to achieve CO2 sequestration at higher pressure rather than end-product inhibition was responsible.

  14. Removal of volatile fatty acids and ammonia recovery from unstable anaerobic digesters with a microbial electrolysis cell.

    Science.gov (United States)

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-11-01

    Continuous assays with a microbial electrolysis cell (MEC) fed with digested pig slurry were performed to evaluate its stability and robustness to malfunction periods of an anaerobic digestion (AD) reactor and its feasibility as a strategy to recover ammonia. When performing punctual pulses of volatile fatty acids (VFA) in the anode compartment of the MEC, simulating a malfunction of the AD process, an increase in the current density was produced (up to 14 times, reaching values of 3500mAm(-2)) as a result of the added chemical oxygen demand (COD), especially when acetate was used. Furthermore, ammonium diffusion from the anode to the cathode compartment was enhanced and the removal efficiency achieved up to 60% during daily basis VFA pulses. An AD-MEC combined system has proven to be a robust and stable configuration to obtain a high quality effluent, with a lower organic and ammonium content.

  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. Biological upgrading of volatile fatty acids, key intermediates for the valorization of biowaste through dark anaerobic fermentation.

    Science.gov (United States)

    Singhania, Reeta Rani; Patel, Anil Kumar; Christophe, Gwendoline; Fontanille, Pierre; Larroche, Christian

    2013-10-01

    VFAs can be obtained from lignocellulosic agro-industrial wastes, sludge, and various biodegradable organic wastes as key intermediates through dark fermentation processes and synthesized through chemical route also. They are building blocks of several organic compounds viz. alcohol, aldehyde, ketones, esters and olefins. These can serve as alternate carbon source for microbial biolipid, biohydrogen, microbial fuel cells productions, methanisation, and for denitrification. Organic wastes are the substrate for VFA platform that is of zero or even negative cost, giving VFA as intermediate product but their separation from the fermentation broth is still a challenge; however, several separation technologies have been developed, membrane separation being the most suitable one. These aspects will be reviewed and results obtained during anaerobic treatment of slaughterhouse wastes with further utilisation of volatile fatty acids for yeast cultivation have been discussed.

  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.

  19. 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.

  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. An inducible fusaric acid tripartite efflux pump contributes to the fusaric acid resistance in Stenotrophomonas maltophilia.

    Directory of Open Access Journals (Sweden)

    Rouh-Mei Hu

    Full Text Available BACKGROUND: Fusaric acid (5-butylpicolinic acid, a mycotoxin, is noxious to some microorganisms. Stenotrophomonas maltophilia displays an intrinsic resistance to fusaric acid. This study aims to elucidate the mechanism responsible for the intrinsic fusaric acid resistance in S. maltophilia. METHODOLOGY: A putative fusaric acid resistance-involved regulon fuaR-fuaABC was identified by the survey of the whole genome sequence of S. maltophilia K279a. The fuaABC operon was verified by reverse transcriptase-PCR. The contribution of the fuaABC operon to the antimicrobial resistance was evaluated by comparing the antimicrobials susceptibility between the wild-type strain and fuaABC knock-out mutant. The regulatory role of fuaR in the expression of the fuaABC operon was assessed by promoter transcription fusion assay. RESULTS: The fuaABC operon was inducibly expressed by fusaric acid and the inducibility was fuaR dependent. FuaR functioned as a repressor of the fuaABC operon in absence of a fusaric acid inducer and as an activator in its presence. Overexpression of the fuaABC operon contributed to the fusaric acid resistance. SIGNIFICANCE: A novel tripartite fusaric acid efflux pump, FuaABC, was identified in this study. Distinct from the formally classification, the FuaABC may constitute a new type of subfamily of the tripartite efflux pump.

  3. Acetic acid fermentation of acetobacter pasteurianus: relationship between acetic acid resistance and pellicle polysaccharide formation.

    Science.gov (United States)

    Kanchanarach, Watchara; Theeragool, Gunjana; Inoue, Taketo; Yakushi, Toshiharu; Adachi, Osao; Matsushita, Kazunobu

    2010-01-01

    Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains.

  4. 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.

  5. Transcription factors FabR and FadR regulate both aerobic and anaerobic pathways for unsaturated fatty acid biosynthesis in Shewanella oneidensis

    Directory of Open Access Journals (Sweden)

    Qixia eLuo

    2014-12-01

    Full Text Available As genes for type II fatty acid synthesis are essential to the growth of Escherichia coli, its sole (anaerobic pathway has significant potential as a target for novel antibacterial drug, and has been extensively studied. Despite this, we still know surprisingly little about fatty acid synthesis in bacteria because this anaerobic pathway in fact is not widely distributed. In this study, we show a novel model of unsaturated fatty acid (UFA synthesis in Shewanella, emerging human pathogens in addition to well-known metal reducers. We identify both anaerobic and aerobic UFA biosynthesis pathways in the representative species, S. oneidensis. Uniquely, the bacterium also contains two regulators FabR and FadR, whose counterparts in other bacteria control the anaerobic pathway. However, we show that in S. oneidensis these two regulators are involved in regulation of both pathways, in either direct or indirect manner. Overall, our results indicate that the UFA biosynthesis and its regulation are far more complex than previously expected, and S. oneidensis serves as a good research model for further work.

  6. Amino acids conferring herbicide resistance in tobacco acetohydroxyacid synthase.

    Science.gov (United States)

    Le, Dung Tien; Choi, Jung-Do; Tran, Lam-Son Phan

    2010-01-01

    Acetohydroxyacid synthase (AHAS) (EC 4.1.3.18) is a target of commercially available herbicides such as sulfonylurea, imidazolinone, and triazolopyrimidine. In plants and microorganisms, AHAS catalyzes the first common reaction in the biosynthesis pathways leading to leucine, isoleucine and valine. Intensive studies using different approaches - including site-directed mutagenesis, molecular modeling and structural analysis - on plant AHAS-s have contributed to the understanding of the herbicide-AHAS interaction. Knowledge of the critical roles of amino acid residues of plant AHAS in conferring herbicide resistance will enable the creation of new herbicide-tolerant AHAS which could be used to develop herbicide-resistant transgenic plants. Moreover, such information will also elucidate design strategies for more efficient herbicides that could also kill weeds resistant to previously used AHAS-inhibiting herbicides. In this review, we summarize the results of intensive searches for amino acid residues and their substitutions that confer herbicide resistance in tobacco AHAS.

  7. Free fatty acid oxidation in insulin resistance and obesity

    OpenAIRE

    Abel, E. Dale

    2010-01-01

    The growing worldwide epidemic of obesity and diabetes portends a significant increase in cardiovascular disease. Obesity is associated with insulin resistance, and there is growing evidence that these conditions independently increase the risk of heart failure. Changes in myocardial substrate utilization develop in obesity and insulin resistance, and are characterized by increased fatty acid oxidation and utilization, and decreased glucose utilization. This paper will review the evidence for...

  8. 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.

  9. Effects of oxytetracycline on archaeal community, and tetracycline resistance genes in anaerobic co-digestion of pig manure and wheat straw.

    Science.gov (United States)

    Wang, Xiaojuan; Pan, Hongjia; Gu, Jie; Qian, Xun; Gao, Hua; Qin, Qingjun

    2016-12-01

    In this study, the effects of different concentrations of oxytetracycline (OTC) on biogas production, archaeal community structure, and the levels of tetracycline resistance genes (TRGs) were investigated in the anaerobic co-digestion products of pig manure and wheat straw. PCR denaturing gradient gel electrophoresis analysis and real-time quantitative polymerase chain reaction (RT-qPCR) (PCR) were used to detect the archaeal community structure and the levels of four TRGs: tet(M), tet(Q), tet(W), and tet(C). The results showed that anaerobic co-digestion with OTC at concentrations of 60, 100, and 140 mg/kg (dry weight of pig manure) reduced the cumulative biogas production levels by 9.9%, 10.4%, and 14.1%, respectively, compared with that produced by the control, which lacked the antibiotic. The addition of OTC substantially modified the structure of the archaeal community. Two orders were identified by phylogenetic analysis, that is, Pseudomonadales and Methanomicrobiales, and the methanogen present during anaerobic co-digestion with OTC may have been resistant to OTC. The abundances of tet(Q) and tet(W) genes increased as the OTC concentration increased, whereas the abundances of tet(M) and tet(C) genes decreased as the OTC concentration increased.

  10. 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.

  11. 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

  12. Effects of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part II: Oleic acid toxicity and biodegradability.

    Science.gov (United States)

    Alves, M M; Vieira, J A; Pereira, R M; Pereira, M A; Mota, M

    2001-01-01

    Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic fixed-bed units. When treating an oleate based effluent, the sludge from the bioreactor that was acclimated with lipids during the first operation period, showed a higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) compared with the sludge fed with a non-fat substrate (IC50 = 80 mg/l). This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l. When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g. stearate that was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day. This suggests the possibility of using adsorption-degradation cycles for the treatment of LCFA based effluents. Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.

  13. 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.

  14. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    Science.gov (United States)

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-01-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal. PMID:28216654

  15. Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

    Science.gov (United States)

    Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

    2017-02-01

    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

  16. 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.

  17. 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)

  18. 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

    2016-04-02

    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 (Pacid 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.

  19. 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

  20. 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

    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 feedi...

  1. 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.

  2. A Simple Method for the Detection of Long-Chain Fatty Acids in an Anaerobic Digestate Using a Quartz Crystal Sensor

    Directory of Open Access Journals (Sweden)

    Takuro Kobayashi

    2016-12-01

    Full Text Available In anaerobic digestion (AD, long-chain fatty acids (LCFAs produced by hydrolysis of lipids, exhibit toxicity against microorganisms when their concentration exceeds several millimolar. An absorption detection system using a quartz crystal microbalance (QCM was developed to monitor the LCFA concentration during an anaerobic digester’s operation treating oily organic waste. The dissociation of the LCFAs considerably improved the sensor response and, moreover, enabled it to specifically detect LCFA from the mixture of LCFA and triglyceride. Under alkaline conditions, the frequency-shift rates of the QCM sensor linearly increased in accordance with palmitic acid concentration in the range of 0–100 mg/L. Frequency changes caused by anaerobic digestate samples were successfully measured after removing suspended solids and adjusting the pH to 10.7. Finally, the QCM measurements for digestate samples demonstrated that frequency-shift rates are highly correlated with LCFA concentrations, which confirmed that the newly developed QCM sensor is helpful for LCFA monitoring in terms of rapidness and usability.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Anaerobic lactic acid degradation during ensilage of whole crop maize inoculated with lactobacillus buchneri inhibits yeast growth and improves aerobic stability

    Science.gov (United States)

    Driehuis; Elferink; Spoelstra

    1999-10-01

    Aerobic deterioration of silages is initiated by (facultative) aerobic micro-organisms, usually yeasts, that oxidize the preserving organic acids. In this study, a Lactobacillus buchneri strain isolated from maize silage was evaluated for its potential as a bacterial inoculant that enhances aerobic stability of silages. In four experiments, chopped whole crop maize (30-43% dry matter (DM)) was inoculated with Lact. buchneri and ensiled in laboratory silos. Uninoculated silages served as controls. Analysis of silages treated with Lact. buchneri at levels of 103-106 cfu g-1 after about 3 months of anaerobic storage showedthat acetic acid and 1-propanol contents increased with inoculum levels above 104 cfu g-1,whereas lactic acid decreased. Propionic acid, silage pH and DM loss increased withinoculum levels above 105 cfu g-1. Time course experiments with maize inoculated with Lact. buchneri at 4 x 104-2 x 105 cfu g-1 showed that up to 7-14 d after ensiling, Lact. buchneri had no effect on silage characteristics. Thereafter, the lactic acid content of the inoculated silages declined and, simultaneously, acetic acid and, to a lesser extent, propionic acid and 1-propanol, accumulated. Inoculation reduced survival of yeasts during the anaerobic storage phase and inhibited yeast growth when the silage was exposed to O2, resulting in a substantial improvement in aerobic stability. The results indicate that the use of Lact. buchneri as a silage inoculant can enhance aerobic stability by inhibition of yeasts. The ability of the organism to ferment lactic acid to acetic acid appears to be an important underlying principle of this effect.

  9. Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ge-Fu; Wu, Peng; Wei, Qun-Shan; Lin, Jian-yi; Liu, Hai-Ning [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Gao, Yan-Li [China University of Geosciences, Wuhan 430074 (China)

    2010-08-15

    Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H{sub 2}) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m{sup 3} d, hydraulic retention time (HRT) of 6 h and temperature of (35 {+-} 1) C, when the pH value, alkalinity and oxidation-reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO{sub 3}/L, and -220 to -250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H{sub 2} volume content was estimated to be 48-53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H{sub 2} production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H{sub 2} production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H{sub 2} production from high-strength chemical wastewater. (author)

  10. 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

  11. The role of zero valent iron on the fate of tetracycline resistance genes and class 1 integrons during thermophilic anaerobic co-digestion of waste sludge and kitchen waste.

    Science.gov (United States)

    Gao, Pin; Gu, Chaochao; Wei, Xin; Li, Xiang; Chen, Hong; Jia, Hanzhong; Liu, Zhenhong; Xue, Gang; Ma, Chunyan

    2017-03-15

    Activated sludge has been identified as a potential significant source of antibiotic resistance genes (ARGs) to the environment. Anaerobic digestion is extensively used for sludge stabilization and resource recovery, and represents a crucial process for controlling the dissemination of ARGs prior to land application of digested sludge. The objective of this study is to investigate the effect of zero valent iron (Fe(0)) on the attenuation of seven representative tetracycline resistance genes (tet, tet(A), tet(C), tet(G), tet(M), tet(O), tet(W), and tet(X)), and the integrase gene intI1 during thermophilic anaerobic co-digestion of waste sludge and kitchen waste. Significant decrease (P  0.05) were found for all gene targets between digesters with Fe(0) dosages of 5 and 60 g/L. A first-order kinetic model favorably described the trends in concentrations of tet and intI1 gene targets during thermophilic anaerobic digestion with or without Fe(0). Notably, tet genes encoding different resistance mechanisms behaved distinctly in anaerobic digesters, although addition of Fe(0) could enhance their reduction. The overall results of this research suggest that thermophilic anaerobic digestion with Fe(0) can be a potential alternative technology for the attenuation of tet and intI1 genes in waste sludge.

  12. 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.

  13. The dynamics of acetic acid in the anaerobic treatment of abattoir sewage; Dinamica del acido acetico en la depuracion anaerobia de aguas residuales de mataderos

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Acosta Viana, K. [Universidad Autonoma de Yucatan. Mexico (Mexico)

    1999-05-01

    The purpose of this experiment was to examine the production and consumption of acetic acid during the anaerobic treatment of sewage from a municipal abattoir. The experiment studied a 20-litre UASB reactor under three hydraulic retention time (HRT) conditions-4 days, 2.5 days and 1.6 days-measuring the acetic acid concentration in the reactor in fluent and effluent. The results obtained during the experiment with the three different HRTs are reported. The highest percentages of acetic acid removed ( an average of 44%) were obtained with an HRT of 4 days. The amount of acetic acid removed with and HRT of 2.5 days was 27%. (Author) 18 refs.

  14. 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.

  15. 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.

  16. Influence of two-phase anaerobic digestion on fate of selected antibiotic resistance genes and class I integrons in municipal wastewater sludge.

    Science.gov (United States)

    Wu, Ying; Cui, Erping; Zuo, Yiru; Cheng, Weixiao; Rensing, Christopher; Chen, Hong

    2016-07-01

    The response of representative antibiotic resistance genes (ARGs) to lab-scale two-phase (acidogenic/methanogenic phase) anaerobic digestion processes under thermophilic and mesophilic conditions was explored. The associated microbial communities and bacterial pathogens were characterized by 16S rRNA gene sequencing. A two-phase thermophilic digestion reduced the presence of tetA, tetG, tetX, sul1, ermB, dfrA1, dfrA12 and intI1 exhibiting 0.1-0.72 log unit removal; in contrast, tetO, tetW, sul3, ermF and blaTEM even increased relative to the feed, and sul2 showed no significant decrease. The acidogenic phase of thermophilic digestion was primarily responsible for reducing the quantity of these genes, while the subsequent methanogenic phase caused a rebound in their quantity. In contrast, a two-phase mesophilic digestion process did not result in reducing the quantity of all ARGs and intI1 except for ermB and blaTEM. ARGs patterns were correlated with Proteobacteria and Actinobacteria during the two-phase anaerobic digestion.

  17. 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.

  18. 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

    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.

  19. 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 ...

  20. 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

  1. 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.

  2. Cultured hypothalamic neurons are resistant to inflammation and insulin resistance induced by saturated fatty acids.

    Science.gov (United States)

    Choi, Sun Ju; Kim, Francis; Schwartz, Michael W; Wisse, Brent E

    2010-06-01

    Hypothalamic inflammation induced by high-fat feeding causes insulin and leptin resistance and contributes to the pathogenesis of obesity. Since in vitro exposure to saturated fatty acids causes inflammation and insulin resistance in many cultured cell types, we determined how cultured hypothalamic neurons respond to this stimulus. Two murine hypothalamic neuronal cell cultures, N43/5 and GT1-7, were exposed to escalating concentrations of saturated fatty acids for up to 24 h. Harvested cells were evaluated for activation of inflammation by gene expression and protein content. Insulin-treated cells were evaluated for induction of markers of insulin receptor signaling (p-IRS, p-Akt). In both hypothalamic cell lines, inflammation was induced by prototypical inflammatory mediators LPS and TNFalpha, as judged by induction of IkappaBalpha (3- to 5-fold) and IL-6 (3- to 7-fold) mRNA and p-IkappaBalpha protein, and TNFalpha pretreatment reduced insulin-mediated p-Akt activation by 30% (P saturated fatty acids on nonneuronal cells.

  3. Complete genome sequence of the bile-resistant pigment- producing anaerobe Alistipes finegoldii type strain (AHN2437T)

    Energy Technology Data Exchange (ETDEWEB)

    Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Stackebrandt, Erko [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Munk, Christine [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Hammon, Nancy [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Gronow, Sabine [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute

    2013-01-01

    Alistipes finegoldii Rautio et al. 2003 is one of five species of Alistipes with a validly pub- lished name: family Rikenellaceae, order Bacteroidetes, class Bacteroidia, phylum Bacteroidetes. This rod-shaped and strictly anaerobic organism has been isolated mostly from human tissues. Here we describe the features of the type strain of this species, together with the complete genome sequence, and annotation. A. finegoldii is the first member of the genus Alistipes for which the complete genome sequence of its type strain is now available. The 3,734,239 bp long single replicon genome with its 3,302 protein-coding and 68 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  4. Overexpression of ESBP6 improves lactic acid resistance and production in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sugiyama, Minetaka; Akase, Shin-Pei; Nakanishi, Ryota; Kaneko, Yoshinobu; Harashima, Satoshi

    2016-10-01

    Polylactic acid plastics are receiving increasing attention for the control of atmospheric CO2 emissions. Lactic acid, the building block for polylactic acid, is produced by fermentation technology from renewable carbon sources. The yeast Saccharomyces cerevisiae, harboring the lactate dehydrogenases gene (LDH), produces lactic acid at a large scale due to its strong acid resistance, to its simple nutritional requirements and to its ease of genetic engineering. Since improvement of lactic acid resistance is correlated with an increase of lactic acid production under non-neutralizing condition, we isolated a novel gene that enhances lactic acid resistance using a multi-copy yeast genomic DNA library. In this study, we identified the ESBP6 gene, which increases lactic acid resistance when overexpressed and which encodes a protein with similarity to monocarboxylate permeases. Although ESBP6 was not induced in response to lactic acid stress, it caused weak but reproducible sensitivity to lactic acid when disrupted. Furthermore, intracellular pH in the ESBP6 overexpressing strain was higher than that in the wild-type strain under lactic acid stressed condition, suggesting that Esbp6 plays some roles in lactic acid adaptation response. The ESBP6 overexpressing strain carrying the LDH gene induced 20% increase in lactic acid production compared with the wild-type strain carrying the LDH gene under non-neutralizing conditions. These results indicate that overexpression of ESBP6 provides a novel and useful tool to improve lactic acid resistance and lactic acid production in yeast.

  5. Arabidopsis YAK1 regulates abscisic acid response and drought resistance

    KAUST Repository

    Kim, Dongjin

    2016-06-06

    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. © 2016 Federation of European Biochemical Societies.

  6. Features of a Clostridium, strain CV-AA1, an obligatory anaerobic bacterium producing acetic acid from methanol.

    Science.gov (United States)

    Adamse, A D; Velzeboer, C T

    1982-01-01

    Isolation and characterization of a new, obligatory, anaerobic, methylotrophic, homoacetogenic bacterium is described. This bacterium is a mesophilic, motile, slightly curved rod that demonstrated a negative Gram reaction, formed spherical, (sub)terminal spores and performed a homoacetic fermentation with methanol, a CO2-2H2-gas mixture, glucose or fructose, respectively, as the substrate. The methanol fermentation proceeded only when a suitable amount of NaHCO3 was available in the nutrient solution supplied.

  7. 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.

  8. Palmitic acid but not palmitoleic acid induces insulin resistance in a human endothelial cell line by decreasing SERCA pump expression.

    Science.gov (United States)

    Gustavo Vazquez-Jimenez, J; Chavez-Reyes, Jesus; Romero-Garcia, Tatiana; Zarain-Herzberg, Angel; Valdes-Flores, Jesus; Manuel Galindo-Rosales, J; Rueda, Angelica; Guerrero-Hernandez, Agustin; Olivares-Reyes, J Alberto

    2016-01-01

    Palmitic acid is a negative regulator of insulin activity. At the molecular level, palmitic acid reduces insulin stimulated Akt Ser473 phosphorylation. Interestingly, we have found that incubation with palmitic acid of human umbilical vein endothelial cells induced a biphasic effect, an initial transient elevation followed by a sustained reduction of SERCA pump protein levels. However, palmitic acid produced a sustained inhibition of SERCA pump ATPase activity. Insulin resistance state appeared before there was a significant reduction of SERCA2 expression. The mechanism by which palmitic acid impairs insulin signaling may involve endoplasmic reticulum stress, because this fatty acid induced activation of both PERK, an ER stress marker, and JNK, a kinase associated with insulin resistance. None of these effects were observed by incubating HUVEC-CS cells with palmitoleic acid. Importantly, SERCA2 overexpression decreased the palmitic acid-induced insulin resistance state. All these results suggest that SERCA pump might be the target of palmitic acid to induce the insulin resistance state in a human vascular endothelial cell line. Importantly, these data suggest that HUVEC-CS cells respond to palmitic acid-exposure with a compensatory overexpression of SERCA pump within the first hour, which eventually fades out and insulin resistance prevails.

  9. 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.

  10. Abscisic acid enhances resistance to Alternaria solani in tomato seedlings.

    Science.gov (United States)

    Song, Weiwei; Ma, Xinrong; Tan, Hong; Zhou, Jinyan

    2011-07-01

    The plant hormone abscisic acid (ABA) is an important regulator in many aspects of plant growth and development, as well as stress resistance. Here, we investigated the effects of exogenous ABA application on the interaction between tomato (Solanum lycopersicon L.) and Alternaria solani (early blight). Foliar spraying of 7.58 μM ABA was effective in reducing disease severity in tomato plants. Previously, increased activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) were observed in exogenous ABA-treated tomato leaves. Moreover, these enzyme activities were maintained at higher levels in ABA-pretreated and A. solani challenged tomato plants. Tomato defense genes, such as PR1, β-1, 3-glucanase (GLU), PPO, POD, and superoxide dismutase (SOD), were rapidly and significantly up-regulated by exogenous ABA treatment. Furthermore, a subsequent challenge of ABA-pretreated plants with the pathogen A. solani resulted in higher expression of defense genes, compared to water-treated or A. solani inoculated plants. Therefore, our results suggest that exogenous ABA could enhance disease resistance against A. solani infection in tomato through the activation of defense genes and via the enhancement of defense-related enzymatic activities.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  16. 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.

  17. 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.

  18. 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.

  19. Development of antibiotic resistance genes in microbial communities during long-term operation of anaerobic reactors in the treatment of pharmaceutical wastewater.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2015-10-15

    Biological treatment processes offer the ideal conditions in which a high diversity of microorganisms can grow and develop. The wastewater produced during these processes is contaminated with antibiotics and, as such, they provide the ideal setting for the acquisition and proliferation of antibiotic resistance genes (ARGs). This research investigated the occurrence and variation in the ARGs found during the one-year operation of the anaerobic sequencing batch reactors (SBRs) used to treat pharmaceutical wastewater that contained combinations of sulfamethoxazole-tetracycline-erythromycin (STE) and sulfamethoxazole-tetracycline (ST). The existence of eighteen ARGs encoding resistance to sulfamethoxazole (sul1, sul2, sul3), erythromycin (ermA, ermF, ermB, msrA, ereA), tetracycline (tetA, tetB, tetC, tetD, tetE, tetM, tetS, tetQ, tetW, tetX) and class Ι integron gene (intΙ 1) in the STE and ST reactors was investigated by quantitative real-time PCR. Due to the limited availability of primers to detect ARGs, Illumina sequencing was also performed on the sludge and effluent of the STE and ST reactors. Although there was good reactor performance in the SBRs, which corresponds to min 80% COD removal efficiency, tetA, tetB, sul1, sul2 and ermB genes were among those ARGs detected in the effluent from STE and ST reactors. A comparison of the ARGs acquired from the STE and ST reactors revealed that the effluent from the STE reactor had a higher number of ARGs than that from the ST reactor; this could be due to the synergistic effects of erythromycin. According to the expression of genes results, microorganisms achieve tetracycline and erythromycin resistance through a combination of three mechanisms: efflux pumping protein, modification of the antibiotic target and modifying enzymes. There was also a significant association between the presence of the class 1 integron and sulfamethoxazole resistance genes.

  20. 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.

  1. 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.

  2. The acid-base resistant zone in three dentin bonding systems.

    Science.gov (United States)

    Inoue, Go; Nikaido, Toru; Foxton, Richard M; Tagami, Junji

    2009-11-01

    An acid-base resistant zone has been found to exist after acid-base challenge adjacent to the hybrid layer using SEM. The aim of this study was to examine the acid-base resistant zone using three different bonding systems. Dentin disks were applied with three different bonding systems, and then a resin composite was light-cured to make dentin disk sandwiches. After acid-base challenge, the polished surfaces were observed using SEM. For both one- and two-step self-etching primer systems, an acid-base resistant zone was clearly observed adjacent to the hybrid layer - but with differing appearances. For the wet bonding system, the presence of an acid-base resistant zone was unclear. This was because the self-etching primer systems etched the dentin surface mildly, such that the remaining mineral phase of dentin and the bonding agent yielded clear acid-base resistant zones. In conclusion, the acid-base resistant zone was clearly observed when self-etching primer systems were used, but not so for the wet bonding system.

  3. 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...

  4. Flow Injection Analysis of Acid and Base using Thermo-Sensitive Resistance Coils

    OpenAIRE

    1995-01-01

    A flow injection analysis of acid-base by detecting neutralization heat is proposed. A injected sample (acid or base), combined with a carrier (deionized water), was mixed with a reagent (base or acid) stream. A change in the solution temperature was detected by passing the solution, immediately after mixing, through a stainless steel capillary tube around which a thermo-sensitive resistance was coiled. The temperature of carrier was used as a reference Hydrochloric acid solutions of 0.003 to...

  5. 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.

  6. 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.

  7. 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.

  8. 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,

  9. 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...

  10. 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.

  11. ENHANCED DISEASE SUSCEPTIBILITY 1 and SALICYLIC ACID act redundantly to regulate resistance gene-mediated signaling

    Science.gov (United States)

    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), ...

  12. Relationship between insulin resistance and amino acids in women and men

    OpenAIRE

    Seibert, Ryan; Abbasi, Fahim; Hantash, Feras M.; Caulfield, Michael P; Reaven, Gerald; Sun H. Kim

    2015-01-01

    Insulin resistance has been associated with higher plasma amino acid (AA) concentrations, but majority of studies have used indirect measures of insulin resistance. Our main objective was to define the relationship between plasma AA concentrations and a direct measure of insulin resistance in women and men. This was a cross-sectional study of 182 nondiabetic individuals (118 women and 64 men) who had measurement of 24 AAs and steady-state plasma glucose (SSPG) concentration (insulin resistanc...

  13. 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...

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. Quantitative analysis of growth and volatile fatty acid production by the anaerobic ruminal bacterium Megasphaera elsdenii T81

    Science.gov (United States)

    Megaspheara elsdenii T81 grew on either DL-lactate or D-glucose at similar rates (0.85 per h), but displayed major differences in the fermentation of these substrates. Lactate was fermented at up to 210-mM concentration to yield acetic, propionic, butyric, and valeric acids. The bacterium was able t...

  19. 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.

  20. 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.

  1. 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%。

  2. Enhanced expression of aconitase raises acetic acid resistance in Acetobacter aceti.

    Science.gov (United States)

    Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

    2004-06-15

    Acetobacter spp. are used for industrial vinegar production because of their high ability to oxidize ethanol to acetic acid and high resistance to acetic acid. Two-dimensional gel electrophoretic analysis of a soluble fraction of Acetobacter aceti revealed the presence of several proteins whose production was enhanced, to various extents, in response to acetic acid in the medium. A protein with an apparent molecular mass of 100 kDa was significantly enhanced in amount by acetic acid and identified to be aconitase by NH2-terminal amino acid sequencing and subsequent gene cloning. Amplification of the aconitase gene by use of a multicopy plasmid in A. aceti enhanced the enzymatic activity and acetic acid resistance. These results showed that aconitase is concerned with acetic acid resistance. Enhancement of the aconitase activity turned out to be practically useful for acetic acid fermentation, because the A. aceti transformant harboring multiple copies of the aconitase gene produced a higher concentration of acetic acid with a reduced growth lag-time.

  3. 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.

  4. 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.

  5. Surface and line-edge roughness in acid-breakable resin-based positive resist

    Science.gov (United States)

    Sakamizu, Toshio; Shiraishi, Hiroshi

    2003-06-01

    A positive chemical amplification resist based on acid-catalyzed fragmentation of acetal groups in its main-chain has been developed as a means for reducing line-edge roughness. The resist consists of an acid-generator, an acid-diffusion controller and an acid-breakable (AB) resin that is synthesized through a co-condensation reaction between polyphenol and aromatic multi-functional vinylether compound. The effects of the fractionation of AB resins on resin properties and line-edge roughness (LER) are evaluated. Although AB resins have wide molecular-weight distributions, the density of acetal groups in this AB resin is found to be almost constant except in the lower molecular-weight components. The resist with a fractionated resin from which such components removed provides the high resolution of 60-nm line-and-space (L/S) patterns with fairly low LER. AFM analysis shows the surface roughness (SR) for the resist with the fractionated resin is smaller than that for a resist using non-fractionated AB resin, and that the SR value is not altered throughout the range of exposure doses up to just below the beginning of dissolution. By using the fractionated AB resin, the AB resin-based resist (ABR) is capable of forming sub-100 nm L/S patterns with less than 5 nm of LER (3σ).

  6. Effects of different free fatty acids on insulin resistance in rats

    Institute of Scientific and Technical Information of China (English)

    Ping Han; Yong-Yan Zhang; Yan Lu; Bing He; Wei Zhang; Fei Xia

    2008-01-01

    BACKGROUND:Much evidence demonstrates that elevated free fatty acids (FFAs) are associated with insulin resistance. However, it is not clear whether different FFAs can cause different degrees of peripheral insulin resistance. This study aimed to investigate the effects of short-term elevation of FFAs on hepatic and peripheral insulin action, and determine whether FFAs with different degrees of saturation have differential effects on hepatic insulin resistance. METHODS:Intralipid+heparin (IH, polyunsaturated fatty acids), oleate (OLE), lard oil+heparin (LOH), and saline (SAL) were separately infused intravenously for 7 hours in normal Wistar rats. During the last 2 hours of the fat/saline infusion, a hyperinsulinemic-euglycemic clamping was performed with [6-3H] glucose tracer. Plasma glucose was measured using the glucose oxygenase method. Plasma insulin and C-peptide were determined by radioimmunoassays. Plasma FFAs were measured using a colorimetric method. RESULTS:Compared with infusion of SAL, plasma FFA levels were signiifcantly elevated by infusions of IH, OLE, and LOH (P CONCLUSIONS:Short-term elevation of FFAs can induce hepatic and peripheral insulin resistance. Polyunsaturated fatty acids induced less hepatic insulin resistance than monounsaturated or saturated fatty acids. However, IH, OLE, and LOH infusions induced similar peripheral insulin resistance.

  7. 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.

  8. Plant Adaptation to Acid Soils: The Molecular Basis for Crop Aluminum Resistance.

    Science.gov (United States)

    Kochian, Leon V; Piñeros, Miguel A; Liu, Jiping; Magalhaes, Jurandir V

    2015-01-01

    Aluminum (Al) toxicity in acid soils is a significant limitation to crop production worldwide, as approximately 50% of the world's potentially arable soil is acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring resistance to Al toxicity has been a focus of intense research interest in the decade since the last article on crop acid soil tolerance was published in this journal. An impressive amount of progress has been made during that time that has greatly increased our understanding of the diversity of Al resistance genes and mechanisms, how resistance gene expression is regulated and triggered by Al and Al-induced signals, and how the proteins encoded by these genes function and are regulated. This review examines the state of our understanding of the physiological, genetic, and molecular bases for crop Al tolerance, looking at the novel Al resistance genes and mechanisms that have been identified over the past ten years. Additionally, it examines how the integration of molecular and genetic analyses of crop Al resistance is starting to be exploited for the improvement of crop plants grown on acid soils via both molecular-assisted breeding and biotechnology approaches.

  9. 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.

  10. Synergetic stress of acids and ammonium on the shift in the methanogenic pathways during thermophilic anaerobic digestion of organics.

    Science.gov (United States)

    Lü, Fan; Hao, Liping; Guan, Dongxing; Qi, Yujiao; Shao, Liming; He, Pinjing

    2013-05-01

    Combined effects of acids and ammonium on functional pathway and microbial structure during organics methanization were investigated by stable isotopic method and quantitative PCR. The results showed that the stress from acids and ammonium was synergetic, resulted in different inhibition for acetoclastic and hydrogenotrophic methanogenesis and syntrophic acetate oxidation, leading to pathway shift. Methane production from acetate was affected more by acetate than by ammonium until the ammonium concentration reached 6-7 g-N/L. When the ammonium concentration exceeded 6 g-N/L, ammonium inhibition was strengthened by the increased concentration of acetate. At a low acetate concentration (50 mmol/L), acetoclastic methanogenesis dominated, regardless of ammonium concentration. At higher acetate concentrations (150 and 250 mmol/L) and at low-medium ammonium levels (1-4 g-N/L), acetate was mainly degraded by acetoclastic methanogenesis, while residual acetate was degraded by a combination of acetoclastic methanogenesis and the syntrophic reaction of syntrophic acetate oxidization and hydrogenotrophic methanogenesis with the latter dominating at 250 mmol/L acetate. At high ammonium levels (6-7 g-N/L), the degradation of acetate in the 150 mmol/L treatment was firstly through a combination of acetoclastic methanogenesis and the syntrophic pathway and then gradually shifted to the syntrophic pathway, while the degradation of acetate in the 250 mmol/L treatment was completely by the syntrophic pathway.

  11. Toxicants inhibiting anaerobic digestion: a review.

    Science.gov (United States)

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  12. 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

  13. Method for rapid detection and identification of chaetomium and evaluation of resistance to peracetic acid.

    Science.gov (United States)

    Nakayama, Motokazu; Hosoya, Kouichi; Tomiyama, Daisuke; Tsugukuni, Takashi; Matsuzawa, Tetsuhiro; Imanishi, Yumi; Yaguchi, Takashi

    2013-06-01

    In the beverage industry, peracetic acid has been increasingly used as a disinfectant for the filling machinery and environment due to merits of leaving no residue, it is safe for humans, and its antiseptic effect against fungi and endospores of bacteria. Recently, Chaetomium globosum and Chaetomium funicola were reported resistant to peracetic acid; however, little is known concerning the detail of peracetic acid resistance. Therefore, we assessed the peracetic acid resistance of the species of Chaetomium and related genera under identical conditions and made a thorough observation of the microstructure of their ascospores by transmission electron microscopy. The results of analyses revealed that C. globosum and C. funicola showed the high resistance to peracetic acid (a 1-D antiseptic effect after 900 s and 3-D antiseptic effect after 900 s) and had thick cell walls of ascospores that can impede the action mechanism of peracetic acid. We also developed specific primers to detect the C. globosum clade and identify C. funicola by using PCR to amplify the β-tubulin gene. PCR with the primer sets designed for C. globosum (Chae 4F/4R) and C. funicola (Cfu 2F/2R) amplified PCR products specific for the C. globosum clade and C. funicola, respectively. PCR with these two primer sets did not detect other fungi involved in food spoilage and environmental contamination. This detection and identification method is rapid and simple, with extremely high specificity.

  14. 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.

  15. 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.

  16. Relationship between insulin resistance and amino acids in women and men.

    Science.gov (United States)

    Seibert, Ryan; Abbasi, Fahim; Hantash, Feras M; Caulfield, Michael P; Reaven, Gerald; Kim, Sun H

    2015-05-01

    Insulin resistance has been associated with higher plasma amino acid (AA) concentrations, but majority of studies have used indirect measures of insulin resistance. Our main objective was to define the relationship between plasma AA concentrations and a direct measure of insulin resistance in women and men. This was a cross-sectional study of 182 nondiabetic individuals (118 women and 64 men) who had measurement of 24 AAs and steady-state plasma glucose (SSPG) concentration (insulin resistance) using the insulin suppression test. Fourteen out of 24 AA concentrations were significantly (P women; only glycine was lower in men. Majority of these AAs were positively associated with SSPG; only glycine concentration was negatively associated. Glutamic acid, isoleucine, leucine, and tyrosine concentrations had the strongest correlation with SSPG (r ≥ 0.4, P women and men, independent of obesity, and similar to traditional markers of insulin resistance (e.g., glucose, triglyceride, high-density lipoprotein cholesterol). Compared with women, men tended to have a more unfavorable AA profile with higher concentration of AAs associated with insulin resistance and less glycine. However, the strength of association between a direct measurement of insulin resistance and AA concentrations were similar between sexes and equivalent to several traditional markers of insulin resistance.

  17. PeaT1-induced systemic acquired resistance in tobacco follows salicylic acid-dependent pathway.

    Science.gov (United States)

    Zhang, Wei; Yang, Xiufen; Qiu, Dewen; Guo, Lihua; Zeng, Hongmei; Mao, Jianjun; Gao, Qiufeng

    2011-04-01

    Systemic acquired resistance (SAR) is an inducible defense mechanism which plays a central role in protecting plants from pathogen attack. A new elicitor, PeaT1 from Alternaria tenuissima, was expressed in Escherichia coil and characterized with systemic acquired resistance to tobacco mosaic virus (TMV). PeaT1-treated plants exhibited enhanced systemic resistance with a significant reduction in number and size of TMV lesions on wild tobacco leaves as compared with control. The quantitative analysis of TMV CP gene expression with real-time quantitative PCR showed there was reduction in TMV virus concentration after PeaT1 treatment. Similarly, peroxidase (POD) activity and lignin increased significantly after PeaT1 treatment. The real-time quantitative PCR revealed that PeaT1 also induced the systemic accumulation of pathogenesis-related gene, PR-1a and PR-1b which are the markers of systemic acquired resistance (SAR), NPR1 gene for salicylic acid (SA) signal transduction pathway and PAL gene for SA synthesis. The accumulation of SA and the failure in development of similar level of resistance as in wild type tobacco plants in PeaT1 treated nahG transgenic tobacco plants indicated that PeaT1-induced resistance depended on SA accumulation. The present work suggested that the molecular mechanism of PeaT1 inducing disease resistance in tobacco was likely through the systemic acquired resistance pathway mediated by salicylic acid and the NPR1 gene.

  18. Gene quantification by the NanoGene assay is resistant to inhibition by humic acids.

    Science.gov (United States)

    Kim, Gha-Young; Wang, Xiaofang; Ahn, Hosang; Son, Ahjeong

    2011-10-15

    NanoGene assay is a magnetic bead and quantum dot nanoparticles based gene quantification assay. It relies on a set of probe and signaling probe DNAs to capture the target DNA via hybridization. We have demonstrated the inhibition resistance of the NanoGene assay using humic acids laden genomic DNA (gDNA). At 1 μg of humic acid per mL, quantitiative PCR (qPCR) was inhibited to 0% of its quantification capability whereas NanoGene assay was able to maintain more than 60% of its quantification capability. To further increase the inhibition resistance of NanoGene assay at high concentration of humic acids, we have identified the specific mechanisms that are responsible for the inhibition. We examined five potential mechanisms with which the humic acids can partially inhibit our NanoGene assay. The mechanisms examined were (1) adsorption of humic acids on the particle surface; (2) particle aggregation induced by humic acids; (3) fluorescence quenching of quantum dots by humic acids during hybridization; (4) humic acids mimicking of target DNA; and (5) nonspecific binding between humic acids and target gDNA. The investigation showed that no adsorption of humic acids onto the particles' surface was observed for the humic acids' concentration. Particle aggregation and fluorescence quenching were also negligible. Humic acids also did not mimic the target gDNA except 1000 μg of humic acids per mL and hence should not contribute to the partial inhibition. Four of the above mechanisms were not related to the inhibition effect of humic acids particularly at the environmentally relevant concentrations (captured by the probe and signaling DNA.

  19. 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.

  20. Ammonium Metabolism Enzymes Aid Helicobacter pylori Acid Resistance

    OpenAIRE

    2014-01-01

    The gastric pathogen Helicobacter pylori possesses a highly active urease to support acid tolerance. Urea hydrolysis occurs inside the cytoplasm, resulting in the production of NH3 that is immediately protonated to form NH4+. This ammonium must be metabolized or effluxed because its presence within the cell is counterproductive to the goal of raising pH while maintaining a viable proton motive force (PMF). Two compatible hypotheses for mitigating intracellular ammonium toxicity include (i) th...

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

    Directory of Open Access Journals (Sweden)

    Chao-Min Wang

    2016-07-01

    Full Text Available (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.

  2. 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.

  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. 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.

  5. Characterization of the epidemic European fusidic acid-resistant impetigo clone of Staphylococcus aureus.

    Science.gov (United States)

    O'Neill, A J; Larsen, A R; Skov, R; Henriksen, A S; Chopra, I

    2007-05-01

    Resistance to the antibiotic fusidic acid in European strains of Staphylococcus aureus causing impetigo has increased in recent years. This increase appears to have resulted from clonal expansion of a strain we have designated the epidemic European fusidic acid-resistant impetigo clone (EEFIC), which carries the fusidic acid resistance determinant fusB on its chromosome. To understand better the properties of the EEFIC responsible for its success, we have performed detailed phenotypic and genotypic characterization of this clone. Molecular typing revealed the EEFIC to be ST123, spa type t171, and agr type IV and therefore unrelated to earlier prevalent fusB(+) strains found in the United Kingdom. EEFIC strains exhibited resistance to fusidic acid, penicillin, and, in some cases, erythromycin, which are all used in the treatment of impetigo. PCR analysis of the EEFIC and complete DNA sequencing of the 39.3 Kb plasmid it harbors identified genes encoding several toxins previously implicated in impetigo (exfoliative toxins A and B and EDIN-C). The location of fusB was mapped on the chromosome and found to be associated with a novel 16.6-kb genomic island integrated downstream of groEL. Although this element is related to classical staphylococcal pathogenicity islands, it does not encode any known virulence factors and consequently has been designated SaRI(fusB) (for "S. aureus resistance island carrying fusB").

  6. 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.

  7. Small noncoding RNA GcvB is a novel regulator of acid resistance in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jin Ye

    2009-04-01

    Full Text Available Abstract Background The low pH environment of the human stomach is lethal for most microorganisms; but not Escherichia coli, which can tolerate extreme acid stress. Acid resistance in E. coli is hierarchically controlled by numerous regulators among which are small noncoding RNAs (sncRNA. Results In this study, we individually deleted seventy-nine sncRNA genes from the E. coli K12-MG1655 chromosome, and established a single-sncRNA gene knockout library. By systematically screening the sncRNA mutant library, we show that the sncRNA GcvB is a novel regulator of acid resistance in E. coli. We demonstrate that GcvB enhances the ability of E. coli to survive low pH by upregulating the levels of the alternate sigma factor RpoS. Conclusion GcvB positively regulates acid resistance by affecting RpoS expression. These data advance our understanding of the sncRNA regulatory network involved in modulating acid resistance in E. coli.

  8. Acid-resistant organic coatings for the chemical industry: a review

    DEFF Research Database (Denmark)

    Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria Grundahl

    2017-01-01

    Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or......, in combination with fiber reinforcement, to replace them. However, degradation mechanisms of organic coatings in acid service are not thoroughly understood and relevant quantitative investigations are scarce. This review describes the uses and limitations of acid-resistant coatings in the chemical industry...... knowledge on chemical and physical degradation mechanisms is required, and that improvements in resistance to elevated temperatures and abrasion would decrease the risk of use and increase the potential application areas of organic coatings exposed to acidic environments in the chemical industry....

  9. 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...

  10. Activation of the Glutamic Acid-Dependent Acid Resistance System in Escherichia coli BL21(DE3) Leads to Increase of the Fatty Acid Biotransformation Activity.

    Science.gov (United States)

    Woo, Ji-Min; Kim, Ji-Won; Song, Ji-Won; Blank, Lars M; Park, Jin-Byung

    The biosynthesis of carboxylic acids including fatty acids from biomass is central in envisaged biorefinery concepts. The productivities are often, however, low due to product toxicity that hamper whole-cell biocatalyst performance. Here, we have investigated factors that influence the tolerance of Escherichia coli to medium chain carboxylic acid (i.e., n-heptanoic acid)-induced stress. The metabolic and genomic responses of E. coli BL21(DE3) and MG1655 grown in the presence of n-heptanoic acid indicated that the GadA/B-based glutamic acid-dependent acid resistance (GDAR) system might be critical for cellular tolerance. The GDAR system, which is responsible for scavenging intracellular protons by catalyzing decarboxylation of glutamic acid, was inactive in E. coli BL21(DE3). Activation of the GDAR system in this strain by overexpressing the rcsB and dsrA genes, of which the gene products are involved in the activation of GadE and RpoS, respectively, resulted in acid tolerance not only to HCl but also to n-heptanoic acid. Furthermore, activation of the GDAR system allowed the recombinant E. coli BL21(DE3) expressing the alcohol dehydrogenase of Micrococcus luteus and the Baeyer-Villiger monooxygenase of Pseudomonas putida to reach 60% greater product concentration in the biotransformation of ricinoleic acid (i.e., 12-hydroxyoctadec-9-enoic acid (1)) into n-heptanoic acid (5) and 11-hydroxyundec-9-enoic acid (4). This study may contribute to engineering E. coli-based biocatalysts for the production of carboxylic acids from renewable biomass.

  11. Role of hepatocyte S6K1 in palmitic acid-induced endoplasmic reticulum stress, lipotoxicity, insulin resistance and in oleic acid-induced protection.

    Science.gov (United States)

    Pardo, Virginia; González-Rodríguez, Águeda; Muntané, Jordi; Kozma, Sara C; Valverde, Ángela M

    2015-06-01

    The excess of saturated free fatty acids, such as palmitic acid, that induces lipotoxicity in hepatocytes, has been implicated in the development of non-alcoholic fatty liver disease also associated with insulin resistance. By contrast, oleic acid, a monounsaturated fatty acid, attenuates the effects of palmitic acid. We evaluated whether palmitic acid is directly associated with both insulin resistance and lipoapoptosis in mouse and human hepatocytes and the impact of oleic acid in the molecular mechanisms that mediate both processes. In human and mouse hepatocytes palmitic acid at a lipotoxic concentration triggered early activation of endoplasmic reticulum (ER) stress-related kinases, induced the apoptotic transcription factor CHOP, activated caspase 3 and increased the percentage of apoptotic cells. These effects concurred with decreased IR/IRS1/Akt insulin pathway. Oleic acid suppressed the toxic effects of palmitic acid on ER stress activation, lipoapoptosis and insulin resistance. Besides, oleic acid suppressed palmitic acid-induced activation of S6K1. This protection was mimicked by pharmacological or genetic inhibition of S6K1 in hepatocytes. In conclusion, this is the first study highlighting the activation of S6K1 by palmitic acid as a common and novel mechanism by which its inhibition by oleic acid prevents ER stress, lipoapoptosis and insulin resistance in hepatocytes.

  12. Plant resistance mechanisms to air pollutants: rhythms in ascorbic acid production during growth under ozone stress

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.H. (Climate Stress Laboratory, USDA, ARS, Beltsville, MD (United States))

    1991-01-01

    Relationships between ozone (O3) tolerance and leaf ascorbic acid concentrations in O3-susceptible (O3-S) 'Hark' and O3-resistant (O3-R) 'Hood' soybean, Glycine max (L.) Merr., cultivars were examined with high-performance liquid chromatography (HPLC). Leaf samples were analyzed at 4 intervals during a 24 h period. Soybean cultivars grown in the greenhouse with charcoal filtered (CF) and nonfiltered (NF) air showed daily oscillations in ascorbic acid production. Highest ascorbic acid levels in leaves during light coincided with highest concentrations of photochemical oxidants in the atmosphere at 2:00 p.m. The resistant genotype produced more ascorbic acid in its trifoliate leaves than did the corresponding susceptible genotype. Under CF air (an O3-reduced environment) O3-S and O3-R cultivars showed rhythms in ascorbic acid production. In NF air (an O3 stress environment) the O3-R cultivar alone showed rhythms in ascorbic acid production. Results indicated that superior O3 tolerance in the Hood soybean cultivar (compared with Hark) was associated with a greater increase in endogenous levels of ascorbic acid. Ascorbic acid may scavenge free radicals and thereby protect cells from injury by O3 or other oxyradical products. Plants defend themselves against photochemical oxidant stress, such as O3, by several mechanisms. Experimental evidence indicates that antioxidant defense systems existing in plant tissues may function to protect cellular components from deleterious effects of photochemical oxidants through endogenous and exogenous controls.

  13. Chemical Changes Associated with Increased Acid Resistance of Er:YAG Laser Irradiated Enamel

    Directory of Open Access Journals (Sweden)

    Jennifer Manuela Díaz-Monroy

    2014-01-01

    Full Text Available Background. An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. Purpose. To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n=12. Group I (control; Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm2, 200 mJ (25.5 J/cm2, and 300 mJ (38.2 J/cm2, respectively. Results. There were significant differences in composition of irradiated groups (with the exception of chlorine and in the amount of calcium released. Conclusions. Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution.

  14. 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 c...... 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.......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...

  15. 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.

  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.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  17. 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.

  18. 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.

  19. 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.

  20. Anaerobic bacteria, the colon and colitis.

    Science.gov (United States)

    Roediger, W E

    1980-02-01

    Anaerobic bacteria constitute more than 90% of the bacteria in the colon. An anaerobic environment is needed to maintain their growth and the production of short-chain fatty acids by these bacteria from carbohydrates. Short-chain fatty acids are rapidly absorbed and essential for metabolic as well as functional welfare of the colonic mucosa. The importance of these acids in water absorption and in the patogenesis of colitis is discussed in relation to the concept of "energy deficiency diseases" of the colonic mucosa.

  1. Salvianolic acid A shows selective cytotoxicity against multidrug-resistant MCF-7 breast cancer cells.

    Science.gov (United States)

    Wang, Xin; Wang, Chunyan; Zhang, Longjiang; Li, Yanjun; Wang, Shouju; Wang, Jiandong; Yuan, Caiyun; Niu, Jia; Wang, Chengsheng; Lu, Guangming

    2015-02-01

    Multidrug resistance (MDR) is a major cause for incurable breast cancer. Salvianolic acid A (SAA), the hydrophilic polyphenolic derivative of Salvia miltiorrhiza Bunge (Danshen/Red Sage), was examined for cytotoxicities to MDR MCF-7 human breast cancer cells and their parental counterparts. We have shown that SAA inhibited proliferation, caused cell cycle arrest at the S phase, and induced apoptosis dose dependently to the two kinds of cancer cells. However, the resistant cells were significantly susceptible to the inhibition of SAA compared with the parental cells. SAA increased the level of reactive oxygen species (ROS) by 6.2-fold in the resistant cells, whereas the level of SAA-induced ROS changed only by 1.6-fold in their parental counterparts. Thus, the data showed that the selective cytotoxicity resulted from the hypersensitivity of the resistant cells to the strongly elevated ROS by SAA. In addition, SAA-triggered apoptosis was associated with increased caspase-3 activity, disrupted mitochondrial membrane potential, downregulated Bcl-2 expression, and upregulated Bax expression in the resistant cells. Moreover, SAA downregulated the level of P-glycoprotein, which was overexpressed in the resistant cells. This indicated that SAA modulated MDR. Furthermore, SAA showed higher antitumor activity than did doxorubicin in xenografts established from the resistant cells. The present work raised a possibility that SAA might be considered a potential choice to overcome MDR for the selective susceptibility of the resistant breast cancer cells to SAA treatment.

  2. 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.

  3. 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

  4. Palmitoleic acid prevents palmitic acid-induced macrophage activation and consequent p38 MAPK-mediated skeletal muscle insulin resistance.

    Science.gov (United States)

    Talbot, Nicola A; Wheeler-Jones, Caroline P; Cleasby, Mark E

    2014-08-05

    Obesity and saturated fatty acid (SFA) treatment are both associated with skeletal muscle insulin resistance (IR) and increased macrophage infiltration. However, the relative effects of SFA and unsaturated fatty acid (UFA)-activated macrophages on muscle are unknown. Here, macrophages were treated with palmitic acid, palmitoleic acid or both and the effects of the conditioned medium (CM) on C2C12 myotubes investigated. CM from palmitic acid-treated J774s (palm-mac-CM) impaired insulin signalling and insulin-stimulated glycogen synthesis, reduced Inhibitor κBα and increased phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase in myotubes. p38 MAPK inhibition or siRNA partially ameliorated these defects, as did addition of tumour necrosis factor-α blocking antibody to the CM. Macrophages incubated with both FAs generated CM that did not induce IR, while palmitoleic acid-mac-CM alone was insulin sensitising. Thus UFAs may improve muscle insulin sensitivity and counteract SFA-mediated IR through an effect on macrophage activation.

  5. 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.

  6. Splice form variant and amino acid changes in MDR49 confers DDT resistance in transgenic Drosophila.

    Science.gov (United States)

    Seong, Keon Mook; Sun, Weilin; Clark, John M; Pittendrigh, Barry R

    2016-03-22

    The ATP-binding cassette (ABC) transporters represent a superfamily of proteins that have important physiological roles in both prokaryotes and eukaryotes. In insects, ABC transporters have previously been implicated in insecticide resistance. The 91-R strain of Drosophila melanogaster has been intensely selected with DDT over six decades. A recent selective sweeps analysis of 91-R implicated the potential role of MDR49, an ABC transporter, in DDT resistance, however, to date the details of how MDR49 may play a role in resistance have not been elucidated. In this study, we investigated the impact of structural changes and an alternative splicing event in MDR49 on DDT-resistance in 91-R, as compared to the DDT susceptible strain 91-C. We observed three amino acid differences in MDR49 when 91-R was compared with 91-C, and only one isoform (MDR49B) was implicated in DDT resistance. A transgenic Drosophila strain containing the 91-R-MDR49B isoform had a significantly higher LD50 value as compared to the 91-C-MDR49B isoform at the early time points (6 h to 12 h) during DDT exposure. Our data support the hypothesis that the MDR49B isoform, with three amino acid mutations, plays a role in the early aspects of DDT resistance in 91-R.

  7. Segmental pulmonary vascular resistances during oleic acid lung injury in rabbits.

    Science.gov (United States)

    Maarek, J M; Grimbert, F

    1994-10-01

    We studied in isolated rabbit lungs the effects of oleic acid (OA) injury on the segmental distribution of vascular resistance. Vascular occlusion pressures were measured in control and OA-injured preparations over 90 min. Capillary filtration coefficient KF,C increased from 0.61 (+/- 0.10) to 0.91 (+/- 0.14) g.min-1.mmHg-1.(100 g)-1 in OA-injured lungs whereas it remained constant in control lungs. Total pulmonary vascular resistance changed little in both control and OA-injured lungs. OA injury resulted in a 15% increase of the double occlusion capillary pressure. In addition, the contribution of the microvascular to the total vascular resistance rose from 8% to 22%. The increase in microvascular resistance was significant 15 min after OA on the arteriolar side and became significant 30 min later on the venular side. Oleic acid injury does not change the total pulmonary vascular resistance but alters the distribution of segmental resistances in the isolated rabbit lung, thereby contributing to the accumulation of lung water in this model of low pressure permeability edema.

  8. Fusidic acid-resistant Staphylococcus aureus in impetigo contagiosa and secondarily infected atopic dermatitis.

    Science.gov (United States)

    Alsterholm, Mikael; Flytström, Ingela; Bergbrant, Ing-Marie; Faergemann, Jan

    2010-01-01

    Fusidic acid-resistant Staphylococcus aureus (FRSA) has been identified as a causative agent in outbreaks of impetigo and its emergence has been associated with increased use of topical fusidic acid. The frequency of FRSA in atopic dermatitis (AD) has been less extensively investigated. The aim of this study was to investigate the bacterial spectrum and frequency of FRSA in patients with impetigo or secondarily infected AD. A prospective study in our clinic in 2004 to 2008 included 38 patients with impetigo and 37 with secondarily infected AD. S. aureus was the predominant finding in all groups (bullous impetigo 92% (12/13), impetigo 76% (19/25) and secondarily infected AD 89% (33/37)). Seventy-five percent of S. aureus were fusidic acid resistant in bullous impetigo, 32% in impetigo and 6.1% in secondarily infected AD (bullous impetigo vs. AD p impetigo vs. AD p impetigo or secondarily infected AD seen at the clinic during the first and last year of the prospective study. In the first year 33% (19/58) of the S. aureus isolates were fusidic acid-resistant in impetigo and 12% (5/43) in secondarily infected AD (p impetigo and 2.2% (1/45) for AD (p impetigo than in AD. FRSA levels were persistently low in AD. Continued restrictive use of topical fusidic acid is advised to limit an increase in FRSA levels in dermatology patients.

  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. 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.

  11. Use of Ekibastuzsk coal ash as a filler for acid resistant plaster

    Energy Technology Data Exchange (ETDEWEB)

    Korsakov, F.F.; Isichenko, I.I.; Kabanov, G.A.

    1981-01-01

    Acid resistant plasters are used extensively at thermal power plants for protection of gas conduits, ash traps with spouts and hydraulic valves, and the internal surfaces of smoke pump housings. The surface being protected is preliminarily cleaned and a No. 16-20 steel grid attached to the surface by electrial welding. In producing the acid resistant plaster, 14-17 parts by weight of sodium silicofluoride are added to 100 parts by weight of sodium water glass; the remainder consists of andesite or diabase meal to the required consistency. The water glass fulfills the role of a binder; the sodium silicofluoride accelerates solidification of the water glass and the andesite and diabase meal serve as fillers. We found, tested in the laboratory and used successfully (under experimental-industrial conditions) a substitute for andesite and diabase meal. This substitute was ash of Ekibastuzsk coal, which was not only comparable to the meal in regard to quality of the acid resistant plaster, but even exceeded andesite and diabase meal in regard to several qualitative indicators. At the present time, a formula is being developed for an acid resistant plaster produced on the basis of water glass, sodium silicofluoride and ash of Ekibastuzsk coal. In order to verify the possibility of using other ashes instead of andesite and diabase meal, we also tested, under laboratory conditions, acid resistant plasters using ash from thermal power plants (TPP's) also burning Karagandinsk, Kuuchekinsk, Kuznetsk and Kansko-Achinsk coals. In compositions produced with polymer binders, Kansko-Achinsk coal ash was one of the best fillers, providing the most favorable physico-mechanical properties of the composition.

  12. 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.

  13. 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....

  14. Leptin receptor polymorphisms interact with polyunsaturated fatty acids to augment risk of insulin resistance and metabolic syndrome in adults

    Science.gov (United States)

    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, andMetSrisk and whether plasma fatty acids,...

  15. 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.

  16. 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

  17. Resistance to herbicides inhibiting the biosynthesis of very-long-chain fatty acids.

    Science.gov (United States)

    Busi, Roberto

    2014-09-01

    Herbicides that act by inhibiting the biosynthesis of very-long-chain fatty acids (VLCFAs) have been used to control grass weeds in major crops throughout the world for the past 60 years. VLCFA-inhibiting herbicides are generally highly selective in crops, induce similar symptoms in susceptible grasses and can be found within the herbicide groups classified by the HRAC as K3 and N. Even after many years of continuous use, only 12 grass weed species have evolved resistance to VLCFA-inhibiting herbicides. Here, the cases of resistance that have evolved in major grass weed species belonging to the Avena, Echinochloa and Lolium genera in three different agricultural systems are reviewed. In particular we explore the possible reasons why VLCFA herbicides have been slow to select resistant weeds, outline the herbicide mode of action and discuss the resistance mechanisms that are most likely to have been selected.

  18. 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

  19. 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.

  20. 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.

  1. 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 ...

  2. Mid-gestational serum uric acid concentration effect on neonate birth weight and insulin resistance in pregnant women

    OpenAIRE

    Nasri, Khadijeh; Razavi, Maryamsadat; Rezvanfar, Mohammad Reza; Mashhadi, Esmat; Chehrei, Ali; Mohammadbeigi, Abolfazl

    2015-01-01

    Objective To investigate the relationship between mid-gestational serum uric acid and birth weight in diabetic pregnant women with or without insulin resistance. Methods: In a prospective cohort study, fasting uric acid, blood glucose, and serum insulin were measured in 247 pregnant women between 20-22 weeks of gestational period. Insulin resistance was estimated using the homeostasis model assessment-insulin resistance (HOMA-IR). Stratification analysis and independent t-test was used to ass...

  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.

  4. 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.

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

    Science.gov (United States)

    Cetecioglu, Zeynep; Ince, Bahar; Gros, Meritxell; Rodriguez-Mozaz, Sara; Barceló, Damia; Ince, Orhan; Orhon, Derin

    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.

  6. 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.

  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. Jasmonic acid involves in grape fruit ripening and resistant against Botrytis cinerea.

    Science.gov (United States)

    Jia, Haifeng; Zhang, Cheng; Pervaiz, Tariq; Zhao, Pengcheng; Liu, Zhongjie; Wang, Baoju; Wang, Chen; Zhang, Lin; Fang, Jinggui; Qian, Jianpu

    2016-01-01

    Fruit ripening is a complex process that is regulated by a signal network. Whereas the regulatory mechanism of abscisic acid has been studied extensively in non-climacteric fruit, little is know about other signaling pathways involved in this process. In this study, we performed that plant hormone jasmonic acid plays an important role in grape fruit coloring and softening by increasing the transcription levels of several ripening-related genes, such as the color-related genes PAL1, DFR, CHI, F3H, GST, CHS, and UFGT; softening-related genes PG, PL, PE, Cell, EG1, and XTH1; and aroma-related genes Ecar, QR, and EGS. Lastly, the fruit anthocyanin, phenol, aroma, and cell wall materials were changed. Jasmonic acid positively regulated its biosynthesis pathway genes LOS, AOS, and 12-oxophytodienoate reductase (OPR) and signal pathway genes COI1 and JMT. RNA interference of grape jasmonic acid pathway gene VvAOS in strawberry fruit appeared fruit un-coloring phenotypes; exogenous jasmonic acid rescued this phenotypes. On the contrary, overexpression of grape jasmonic acid receptor VvCOI1 in the strawberry fruit accelerated the fruit-ripening process and induced some plant defense-related gene expression level. Furthermore, jasmonic acid treatment or strong jasmonic acid signal pathway in strawberry fruit make the fruit resistance against Botrytis cinerea.

  9. 谷氨酸棒状杆菌厌氧产丁二酸的发酵条件%Influence of lactate dehydrogenase gene knockout on anaerobic production of succinic acid by Corynebacterium glutamicum

    Institute of Scientific and Technical Information of China (English)

    贾全栋; 刘学胜; 郭燕风; 徐建中; 张伟国

    2014-01-01

    考察谷氨酸棒状杆菌ATCC13032Δldh厌氧产丁二酸的发酵条件。结果发现:补加NaHCO3的效果最好,并且考察了NaHCO3浓度对葡萄糖转化速率及丁二酸生成速率的影响。运用代谢流分析方法分析了乳酸脱氢酶基因敲除对谷氨酸棒状杆菌厌氧代谢的影响,发现乳酸脱氢酶基因敲除导致磷酸烯醇式丙酮酸生成丁二酸的流量提高了214�3%,流向乳酸的流量变为0;分批厌氧转化36 h生成41�2 g/L丁二酸,产率45�0%。%The conversion conditions of Corynebacterium glutamicum ATCC13032Δldh under anaerobic condition were investigated.The optimal carbonates were bicarbonate,and the rate of sugar consumption and succinic acid production were influenced by bicarbonate concentration�The effects of lactate dehydrogenase deletion in Corynebacterium glutamicum under anaerobic metabolism were investigated by the metabolic flux analysis and the metabolic flux to the succinic acid synthesis pathway increased by 214�3%, while the metabolic flux to lactic acid synthesis pathway became zero�Succinic acid concentration reached 41�2 g/L within 36 h and the yield of succinic acid was 45.0%.

  10. Superhydrophobic copper surfaces fabricated by fatty acid soaps in aqueous solution for excellent corrosion resistance

    Science.gov (United States)

    Xu, Wenlong; Hu, Yuanyuan; Bao, Wenda; Xie, Xiaoyu; Liu, Yiran; Song, Aixin; Hao, Jingcheng

    2017-03-01

    A simple and safe one-step immersion method was developed to obtain the stable superhydrophobic copper surfaces with excellent corrosion resistance ability using fatty acids in water-medium instead of ethanol. An organic alkali, N,N-dimethylcyclohexylamine (DMCHA), was chosen to solve the poor solubility of fatty acids in water and the high Krafft point of carboxylate salts with inorganic counterions. The superhydrophobic property can be realized in a much quicker process (7.5 min) in aqueous solution than in ethanol (more than 2 d), which is universally feasible for the fabrication of superhydrophobic metal surfaces in industry scale, thereby greatly increasing the safety in industrial manufacture.

  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. Plasminogen activator inhibitor-1, free fatty acids, and insulin resistance in patients with myocardial infarction

    Directory of Open Access Journals (Sweden)

    Gruzdeva O

    2013-08-01

    Full Text Available Olga Gruzdeva, Evgenya Uchasova, Yulia Dyleva, Ekaterina Belik, Ekaterina Shurygina, Olga Barbarash Research Institute for Complex Issues of Cardiovascular Diseases under the Siberian Branch of the Russian Academy of Medical Sciences, Kemerovo, Russian Federation Background: Insulin resistance is known to be a common feature of type 2 diabetes mellitus and is regarded as an important mechanism in the pathogenesis of this disease. The key pathogenetic mechanisms of insulin resistance progression are free fatty acids metabolism impairment and enhanced activity of plasminogen activator inhibitor 1. Both free fatty acids and plasminogen activator inhibitor 1 are recognized as risk factors for coronary heart disease. Methods: The patients were divided into two groups: group 1 included 65 non-diabetic myocardial infarction patients and group 2 enrolled 60 diabetic myocardial infarction patients. The control group consisted of 30 sex- and age-matched volunteers. The concentration of serum free fatty acids, glucose, C-peptide, and insulin were measured on the 1st and 12th days of the study. All the patients had their postprandial glycemia, insulin, and C-peptide concentrations measured 2 hours after a standard carbohydrate breakfast containing 360 kcal (protein 20 g, carbohydrate 57 g, and fat 9 g. Results: Free fatty acids levels in group 1 and in group 2 exceeded the control group values by 7-fold and 11-fold, respectively. Plasminogen activator inhibitor 1 concentration was 2.5-fold higher in group 1 and 4.6-fold higher in group 2 compared to the control group on the 1st day from the myocardial infarction onset. In addition, plasminogen activator inhibitor 1 concentration was significantly reduced in both groups on the 12th day from the myocardial infarction onset; however, it did not achieve the control group values. Conclusion: Increased postprandial glucose level, insulinemia, and elevated levels of free fatty acids and plasminogen activator

  13. Resistance and Tolerance to Tropodithietic Acid, an Antimicrobial in Aquaculture, Is Hard To Select▿ †

    OpenAIRE

    Porsby, Cisse Hedegaard; Webber, Mark A.; Nielsen, Kristian Fog; Piddock, Laura J. V.; Gram, Lone

    2011-01-01

    The antibacterial compound tropodithietic acid (TDA) is produced by bacteria of the marine Roseobacter clade and is thought to explain the fish probiotic properties of some roseobacters. The aim of the present study was to determine the antibacterial spectrum of TDA and the likelihood of development of TDA resistance. A bacterial extract containing 95% TDA was effective against a range of human-pathogenic bacteria, including both Gram-negative and Gram-positive bacteria. TDA was bactericidal ...

  14. Dumb and dumber--the potential waste of a useful antistaphylococcal agent: emerging fusidic acid resistance in Staphylococcus aureus.

    Science.gov (United States)

    Howden, Benjamin P; Grayson, M Lindsay

    2006-02-01

    Fusidic acid has activity against a range of pathogens but has mainly been used to treat staphylococcal infections. Fusidic acid monotherapy, especially topical preparations, has been strongly associated with the emergence of fusidic acid resistance among both methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus. Key resistance determinants include mutations in the fusA gene, which encodes elongation factor G, and plasmid-mediated resistance (i.e., acquisition of resistance gene fusB). Clonal outbreaks of fusidic acid-resistant S. aureus have been noted throughout the United Kingdom and Europe, such that the efficacy of fusidic acid is threatened. Fusidic acid in combination with other agents, such as rifampicin, has proven effective for difficult-to-treat MRSA infections and provides a convenient oral alternative to oxazolidinones. Ensuring that systemic fusidic acid is always used in combination and that the use of topical fusidic acid is either abolished or restricted will be vital if we are to prevent the loss of this potentially useful agent.

  15. 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.

  16. 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.

  17. Genetic evidence of a causal effect of insulin resistance on branched-chain amino acid levels

    DEFF Research Database (Denmark)

    Mahendran, Yuvaraj; Jonsson, Anna; Have, Christian T

    2017-01-01

    AIMS/HYPOTHESIS: Fasting plasma levels of branched-chain amino acids (BCAAs) are associated with insulin resistance, but it remains unclear whether there is a causal relation between the two. We aimed to disentangle the causal relations by performing a Mendelian randomisation study using genetic...... variants associated with circulating BCAA levels and insulin resistance as instrumental variables. METHODS: We measured circulating BCAA levels in blood plasma by NMR spectroscopy in 1,321 individuals from the ADDITION-PRO cohort. We complemented our analyses by using previously published genome...... variable for insulin resistance. A GRS of three variants increasing circulating BCAA levels was used as an instrumental variable for circulating BCAA levels. RESULTS: Fasting plasma BCAA levels were associated with higher HOMA-IR in ADDITION-PRO (β 0.137 [95% CI 0.08, 0.19] p = 6 × 10(-7)). However...

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

    Science.gov (United States)

    Fraqueza, Maria João

    2015-11-06

    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.

  19. 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.

  20. 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.

  1. 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.

  2. Palmitic acid induces central leptin resistance and impairs hepatic glucose and lipid metabolism in male mice.

    Science.gov (United States)

    Cheng, Licai; Yu, Yinghua; Szabo, Alexander; Wu, Yizhen; Wang, Hongqin; Camer, Danielle; Huang, Xu-Feng

    2015-05-01

    The consumption of diets rich in saturated fat largely contributes to the development of obesity in modern societies. A diet high in saturated fats can induce inflammation and impair leptin signaling in the hypothalamus. However, the role of saturated fatty acids on hypothalamic leptin signaling, and hepatic glucose and lipid metabolism remains largely undiscovered. In this study, we investigated the effects of intracerebroventricular (icv) administration of a saturated fatty acid, palmitic acid (PA, C16:0), on central leptin sensitivity, hypothalamic leptin signaling, inflammatory molecules and hepatic energy metabolism in C57BL/6J male mice. We found that the icv administration of PA led to central leptin resistance, evidenced by the inhibition of central leptin's suppression of food intake. Central leptin resistance was concomitant with impaired hypothalamic leptin signaling (JAK2-STAT3, PKB/Akt-FOXO1) and a pro-inflammatory response (TNF-α, IL1-β, IL-6 and pIκBa) in the mediobasal hypothalamus and paraventricular hypothalamic nuclei. Furthermore, the pre-administration of icv PA blunted the effect of leptin-induced decreases in mRNA expression related to gluconeogenesis (G6Pase and PEPCK), glucose transportation (GLUT2) and lipogenesis (FAS and SCD1) in the liver of mice. Therefore, elevated central PA concentrations can induce pro-inflammatory responses and leptin resistance, which are associated with disorders of energy homeostasis in the liver as a result of diet-induced obesity.

  3. Characterization and performance of carbonaceous materials obtained from exhausted sludges for the anaerobic biodecolorization of the azo dye Acid Orange II

    Energy Technology Data Exchange (ETDEWEB)

    Athalathil, S.; Stüber, F.; Bengoa, C.; Font, J. [Departament d’Enginyeria Quimica, ETSEQ, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya (Spain); Fortuny, A. [Departament d’Enginyeria Quimica, EPSEVG, Universitat Politecnica de Catalunya, Av. Victor Balaguer s/n, 08800 Vilanova i la Geltru, Catalunya (Spain); Fabregat, A., E-mail: azael.fabregat@urv.cat [Departament d’Enginyeria Quimica, ETSEQ, Universitat Rovira i Virgili, Av. Paisos Catalans 26, 43007 Tarragona, Catalunya (Spain)

    2014-02-01

    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 ZnCl{sub 2} 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 m{sup 2}/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.

  4. 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....

  5. 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.

  6. 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.

  7. Stearidonic and γ-linolenic acids in echium oil improves glucose disposal in insulin resistant monkeys.

    Science.gov (United States)

    Kavanagh, K; Flynn, D M; Jenkins, K A; Wilson, M D; Chilton, F H

    2013-07-01

    Echium oil (EO) contains stearidonic acid (18:4), a n-3 polyunsaturated fatty acids (PUFAs), and gamma-linolenic acids (18:3), a n-6 PUFA that can be converted to long chain (LC)-PUFAs. We aimed to compare a safflower oil (SO)-enriched diet to EO- and fish oil (FO)-enriched diets on circulating and tissue PUFAs levels and glycemic, inflammatory, and cardiovascular health biomarkers in insulin resistant African green monkeys. In a Latin-square cross-over study, eight monkeys consumed matched diets for 6 weeks with 3-week washout periods. Monkeys consuming FO had significantly higher levels of n-3 LC-PUFAs and EO supplementation resulted in higher levels of circulating n-3 LC-PUFAs and a significant increase in dihomo-gamma linolenic acid (DGLA) in red blood cells and muscle. Glucose disposal was improved after EO consumption. These data suggest that PUFAs in EO supplementation have the capacity to alter circulating, RBC and muscle LC-PUFA levels and improve glucose tolerance in insulin-resistant monkeys.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Combining disulfiram and poly(l-glutamic acid)-cisplatin conjugates for combating cisplatin resistance.

    Science.gov (United States)

    Song, Wantong; Tang, Zhaohui; Shen, Na; Yu, Haiyang; Jia, Yanjie; Zhang, Dawei; Jiang, Jian; He, Chaoliang; Tian, Huayu; Chen, Xuesi

    2016-06-10

    A poly(l-glutamic acid) graft polyethylene glycol-cisplatin complex (PGA-CisPt) performs well in reducing the toxicity of free cisplatin and greatly enhances the accumulation and retention of cisplatin in solid tumors. However, there is a lack of effective treatment options for cisplatin-resistant tumors. A major reason for this is the dense PEG shell, which ensures that the PGA-CisPt maintains a long retention time in the blood that may result in it bypassing the tumor cells or failing to be endocytosed within the tumor microenvironment. Consequently, the cisplatin from PGA-CisPt is released to the extracellular space in the presence of cisplatin-resistant tumor cells and the resistant problem to free cisplatin still valid. Therefore, we devised a strategy to combat the resistance of cisplatin in the tumor microenvironment using nanoparticles-loaded disulfiram (NPs-DSF) as a modulator. In vitro, cisplatin, in combination with DSF, had a synergistic effect and decreased cell survival rate of cisplatin-resistant A549DDP cells. This effect was also observed when combining PGA-CisPt with NPs-DSF. Similarly, in Balb/C nude mice with A549DDP xenografts, NPs-DSF improved PGA-CisPt effectiveness in inhibiting tumor growth while maintaining low toxicity. Our data demonstrate that DSF reduces intracellular glutathione (GSH) levels, inhibits NFκB activity, and modulates the expression of apoptosis-related proteins Bcl-2 and Bax, thereby improves the effectiveness of cisplatin in resistant cell lines. Here, we provide a promising method for overcoming cisplatin resistance in tumors, while maintaining the in vivo benefits of the PGA-CisPt complex.

  15. Escherichia coli O157:H7 Glutamate- and Arginine-dependent Acid Resistance Systems Protect Against Oxidative Stress During Extreme Acid Challenge

    Science.gov (United States)

    To investigate the protection that several known Escherichia coli O157:H7 acid resistance systems provide against oxidative stress, the addition of diamide or hydrogen peroxide were used concomitant with acid challenge at pH 2.5 to determine bacterial survival. Diamide and hydrogen peroxide both de...

  16. 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.

  17. Resistance to benzalkonium chloride, peracetic acid and nisin during formation of mature biofilms by Listeria monocytogenes.

    Science.gov (United States)

    Saá Ibusquiza, P; Herrera, J J R; Cabo, M L

    2011-05-01

    Increase of resistance to the application of benzalkonium chloride (BAC), peracetic acid (PA) and nisin during biofilm formation at 25 °C by three strains of Listeria monocytogenes (CECT 911, CECT 4032, CECT 5873 and BAC-adapted CECT 5873) in different scenarios was compared. For this purpose, resistance after 4 and 11-days of biofilm formation was quantified in terms of lethal dose 90% values (LD(90)), determined according with a dose-response logistic mathematical model. Microscopic analyses after 4 and 11-days of L. monocytogenes biofilm formation were also carried out. Results demonstrated a relation between the microscopic structure and the resistance to the assayed biocides in matured biofilms. The worst cases being biofilms formed by the strain 4032 (in both stainless steel and polypropylene), which showed a complex "cloud-type" structure that correlates with the highest resistance of this strain against the three biocides during biofilm maturation. However, that increase in resistance and complexity appeared not to be dependent on initial bacterial adherence, thus indicating mature biofilms rather than planctonic cells or early-stage biofilms must be considered when disinfection protocols have to be optimized. PA seemed to be the most effective of the three disinfectants used for biofilms. We hypothesized both its high oxidizing capacity and low molecular size could suppose an advantage for its penetration inside the biofilm. We also demonstrated that organic material counteract with the biocides, thus indicating the importance of improving cleaning protocols. Finally, by comparing strains 5873 and 5873 adapted to BAC, several adaptative cross-responses between BAC and nisin or peracetic acid were identified.

  18. Organic acids enhance bioavailability of tetracycline in water to Escherichia coli for uptake and expression of antibiotic resistance.

    Science.gov (United States)

    Zhang, Yingjie; Boyd, Stephen A; Teppen, Brian J; Tiedje, James M; Li, Hui

    2014-11-15

    Tetracyclines are a large class of antimicrobials used most extensively in livestock feeding operations. A large portion of tetracyclines administered to livestock is excreted in manure and urine which is collected in waste lagoons. Subsequent land application of these wastes introduces tetracyclines into the soil environment, where they could exert selective pressure for the development of antibiotic resistance genes in bacteria. Tetracyclines form metal-complexes in natural waters, which could reduce their bioavailability for bacterial uptake. We hypothesized that many naturally-occurring organic acids could effectively compete with tetracyclines as ligands for metal cations, hence altering the bioavailability of tetracyclines to bacteria in a manner that could enhance the selective pressure. In this study, we investigated the influence of acetic acid, succinic acid, malonic acid, oxalic acid and citric acid on tetracycline uptake from water by Escherichia coli bioreporter construct containing a tetracycline resistance gene which induces the emission of green fluorescence when activated. The presence of the added organic acid ligands altered tetracycline speciation in a manner that enhanced tetracycline uptake by E. coli. Increased bacterial uptake of tetracycline and concomitant enhanced antibiotic resistance response were quantified, and shown to be positively related to the degree of organic acid ligand complexation of metal cations in the order of citric acid > oxalic acid > malonic acid > succinic acid > acetic acid. The magnitude of the bioresponse increased with increasing aqueous organic acid concentration. Apparent positive relation between intracellular tetracycline concentration and zwitterionic tetracycline species in aqueous solution indicates that (net) neutral tetracycline is the species which most readily enters E. coli cells. Understanding how naturally-occurring organic acid ligands affect tetracycline speciation in solution, and how speciation

  19. Reprogramming of fatty acid and oxylipin synthesis in rhizobacteria-induced systemic resistance in tomato.

    Science.gov (United States)

    Mariutto, Martin; Fauconnier, Marie-Laure; Ongena, Marc; Laloux, Morgan; Wathelet, Jean-Paul; du Jardin, Patrick; Thonart, Philippe; Dommes, Jacques

    2014-03-01

    The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme of the oxylipin pathway, the lipoxygenase (LOX), leading to a faster accumulation of its product, the free 13-hydroperoxy octadecatrienoic acid (13-HPOT), 2 days after Botrytis cinerea inoculation. In the present study, we further investigated the stimulation of the oxylipin pathway: metabolites and enzymes of the pathway were analyzed to understand the fate of the 13-HPOT in ISR. Actually the stimulation began upstream the LOX: free linolenic acid accumulated faster in P. putida BTP1-treated plants than in control. Downstream, the LOX products 13-fatty acid hydroperoxides esterified to galactolipids and phospholipids were more abundant in bacterized plants than in control before infection. These metabolites could constitute a pool that will be used after pathogen attack to produce free fungitoxic metabolites through the action of phospholipase A2, which is enhanced in bacterized plants upon infection. Enzymatic branches which can use as substrate the fatty acid hydroperoxides were differentially regulated in bacterized plants in comparison to control plants, so as to lead to the accumulation of the most fungitoxic compounds against B. cinerea. Our study, which is the first to demonstrate the accumulation of an esterified defense metabolite during rhizobacteria-mediated induced systemic resistance, showed that the oxylipin pathway is differentially regulated. It suggests that this allows the plant to prepare to a future infection, and to respond faster and in a more effective way to B. cinerea invasion.

  20. 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.

  1. Further characterization of three Yersinia enterocolitica strains with a nalidixic acid-resistant phenotype isolated from humans with diarrhea.

    Science.gov (United States)

    Drummond, Niall; Stephan, Roger; Haughton, Pippa; Murphy, Brenda P; Fanning, Séamus

    2013-08-01

    Antimicrobial-resistant bacteria pose a threat to public health. Three Yersinia enterocolitica strains cultured from patients presenting with diarrhea and resistant to nalidixic acid were studied. Target gene mutations in gyrA alone were identified as part of the genetic basis for this phenotype. Efflux activity was also noted, since the presence of the efflux pump inhibitor, phenylalanine-arginine-β-naphthylamide, increased susceptibility to nalidixic acid.

  2. 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.

  3. 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.

  4. 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.

  5. Characterization of a Pipecolic Acid Biosynthesis Pathway Required for Systemic Acquired Resistance.

    Science.gov (United States)

    Ding, Pingtao; Rekhter, Dmitrij; Ding, Yuli; Feussner, Kirstin; Busta, Lucas; Haroth, Sven; Xu, Shaohua; Li, Xin; Jetter, Reinhard; Feussner, Ivo; Zhang, Yuelin

    2016-10-01

    Systemic acquired resistance (SAR) is an immune response induced in the distal parts of plants following defense activation in local tissue. Pipecolic acid (Pip) accumulation orchestrates SAR and local resistance responses. Here, we report the identification and characterization of SAR-DEFICIENT4 (SARD4), which encodes a critical enzyme for Pip biosynthesis in Arabidopsis thaliana Loss of function of SARD4 leads to reduced Pip levels and accumulation of a Pip precursor, Δ(1)-piperideine-2-carboxylic acid (P2C). In Escherichia coli, expression of the aminotransferase ALD1 leads to production of P2C and addition of SARD4 results in Pip production, suggesting that a Pip biosynthesis pathway can be reconstituted in bacteria by coexpression of ALD1 and SARD4. In vitro experiments showed that ALD1 can use l-lysine as a substrate to produce P2C and P2C is converted to Pip by SARD4. Analysis of sard4 mutant plants showed that SARD4 is required for SAR as well as enhanced pathogen resistance conditioned by overexpression of the SAR regulator FLAVIN-DEPENDENT MONOOXYGENASE1. Compared with the wild type, pathogen-induced Pip accumulation is only modestly reduced in the local tissue of sard4 mutant plants, but it is below detection in distal leaves, suggesting that Pip is synthesized in systemic tissue by SARD4-mediated reduction of P2C and biosynthesis of Pip in systemic tissue contributes to SAR establishment.

  6. The Emerging Role of Branched-Chain Amino Acids in Insulin Resistance and Metabolism

    Directory of Open Access Journals (Sweden)

    Mee-Sup Yoon

    2016-07-01

    Full Text Available Insulin is required for maintenance of glucose homeostasis. Despite the importance of insulin sensitivity to metabolic health, the mechanisms that induce insulin resistance remain unclear. Branched-chain amino acids (BCAAs belong to the essential amino acids, which are both direct and indirect nutrient signals. Even though BCAAs have been reported to improve metabolic health, an increased BCAA plasma level is associated with a high risk of metabolic disorder and future insulin resistance, or type 2 diabetes mellitus (T2DM. The activation of mammalian target of rapamycin complex 1 (mTORC1 by BCAAs has been suggested to cause insulin resistance. In addition, defective BCAA oxidative metabolism might occur in obesity, leading to a further accumulation of BCAAs and toxic intermediates. This review provides the current understanding of the mechanism of BCAA-induced mTORC1 activation, as well as the effect of mTOR activation on metabolic health in terms of insulin sensitivity. Furthermore, the effects of impaired BCAA metabolism will be discussed in detail.

  7. 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.

  8. Pomegranate seed oil, a rich source of punicic acid, prevents diet-induced obesity and insulin resistance in mice.

    NARCIS (Netherlands)

    Vroegrijk, I.O.; Diepen, J.A. van; Berg, S.; Westbroek, I.; Keizer, H.; Gambelli, L.; Hontecillas, R.; Bassaganya-Riera, J.; Zondag, G.C.; Romijn, J.A.; Havekes, L.M.; Voshol, P.J.

    2011-01-01

    BACKGROUND: Pomegranate seed oil has been shown to protect against diet induced obesity and insulin resistance. OBJECTIVE: To characterize the metabolic effects of punicic acid on high fat diet induced obesity and insulin resistance. DESIGN: High-fat diet or high-fat diet with 1% Pomegranate seed oi

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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.

  14. Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens

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    Joseph R. Pittman

    2015-10-01

    Full Text Available The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance. To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C, low pH (pH 2.8, and oxidative stress (15 mM H2O2. In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth.

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

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    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

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

    Science.gov (United States)

    Jensen, Holly A; Bunaciu, Rodica P; Ibabao, Christopher N; Myers, Rebecca; Varner, Jeffrey D; Yen, Andrew

    2014-01-01

    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 (unilineage

  17. 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.

  18. Characterisation of a cell wall-anchored protein of Staphylococcus saprophyticus associated with linoleic acid resistance

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    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

  19. 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.

  20. 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.

  1. 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...

  2. Dietary Docosahexaenoic Acid and Eicosapentaenoic Acid Influence Liver Triacylglycerol and Insulin Resistance in Rats Fed a High-Fructose Diet

    Directory of Open Access Journals (Sweden)

    Gabriela Salim de Castro

    2015-04-01

    Full Text Available This study aimed to examine the benefits of different amounts of omega-3 (n-3 polyunsaturated fatty acids from fish oil (FO on lipid metabolism, insulin resistance and gene expression in rats fed a high-fructose diet. Male Wistar rats were separated into two groups: Control (C, n = 6 and Fructose (Fr, n = 32, the latter receiving a diet containing 63% by weight fructose for 60 days. After this period, 24 animals from Fr group were allocated to three groups: FrFO2 (n = 8 receiving 63% fructose and 2% FO plus 5% soybean oil; FrFO5 (n = 8 receiving 63% fructose and 5% FO plus 2% soybean oil; and FrFO7 (n = 8 receiving 63% fructose and 7% FO. Animals were fed these diets for 30 days. Fructose led to an increase in liver weight, hepatic and serum triacylglycerol, serum alanine aminotransferase and HOMA1-IR index. These alterations were reversed by 5% and 7% FO. FO had a dose-dependent effect on expression of genes related to hepatic β-oxidation (increased and hepatic lipogenesis (decreased. The group receiving the highest FO amount had increased markers of oxidative stress. It is concluded that n-3 fatty acids may be able to reverse the adverse metabolic effects induced by a high fructose diet.

  3. [Tartrate-resistant acid phosphatase in free-living Amoeba proteus].

    Science.gov (United States)

    Sopina, V A

    2002-01-01

    Tartrate-resistant acid phosphatase (TRAP) of Amoeba proteus (strain B) was represented by 3 of 6 bands (= electromorphs) revealed after disc-electrophoresis in polyacrylamide gels with the use of 2-naphthyl phosphate as a substrate at pH 4.0. The presence of MgCl2, CaCl2 or ZnCl2 (50 mM) in the incubation mixture used for gel staining stimulated activities of all 3 TRAP electromorphs or of two of them (in the case of ZnCl2). When gels were treated with MgCl2, CaCl2 or ZnCl2 (10 and 100 mM, 30 min) before their staining activity of TRAP electromorphs also increased. But unlike 1 M MgCl2 or 1 M CaCl2, 1 M ZnCl2 partly inactivated two of the three TRAP electromorphs. EDTA and EGTA (5 mM), and H2O2 (10 mM) completely inhibited TRAP electromorphs after gel treatment for 10, 20 and 30 min, resp. Of 5 tested ions (Mg2+, Ca2+, Fe2+, Fe3+ and Zn2+), only the latter reactivated the TRAP electromorphs previously inactivated by EDTA or EGTA treatment. In addition, after EDTA inactivation, TRAP electromorphs were reactivated better than after EGTA. The resistance of TRAP electromorphs to okadaic acid and phosphatase inhibitor cocktail 1 used in different concentrations is indicative of the absence of PP1 and PP2A among these electromorphs. Mg2+, Ca2+ and Zn2+ dependence of TRAP activity, and the resistance of its electromorphs to vanadate and phosphatase inhibitor cocktail 2 prevents these electromorphs from being classified as PTP. It is suggested that the active center of A. proteus TRAP contains zinc ion, which is essential for catalytic activity of the enzyme. Thus, TRAP of these amoebae is metallophosphatase showing phosphomonoesterase activity in acidic medium. This metalloenzyme differs from both mammalian tartrate-resistant PAPs and tartrate-resistant metallophosphatase of Rana esculenta.

  4. 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-

  5. Hypochlorous acid via peroxynitrite activates protein kinase Cθ and insulin resistance in adipocytes

    OpenAIRE

    Zhou, Jun; Wang, Qilong; Ding, Ye; Zou, Ming-hui

    2015-01-01

    We recently reported that genetic deletion of myeloperoxidase (MPO) alleviates obesity-related insulin resistance in mice in vivo. How MPO impairs insulin sensitivity in adipocytes is poorly characterized. As hypochlorous acid (HOCl) is a principal oxidant product generated by MPO, we evaluated the effects of HOCl on insulin signaling in adipocytes differentiated from 3T3-L1 cells. Exposure of 3T3-L1 adipocytes to exogenous HOCl (200 μmol/l) attenuated insulin-stimulated 2-deoxyglucose uptake...

  6. 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.

  7. Performance and microbial community variations of anaerobic digesters under increasing tetracycline concentrations

    KAUST Repository

    Xiong, Yanghui

    2017-04-01

    The impact of different concentrations of tetracycline on the performance of anaerobic treatment was evaluated. Results revealed that for all of the tested tetracycline concentrations, no major sustained impact on methane production was observed. Instead, a significant increase in propionic acid was observed in the reactor subjected to the highest concentration of tetracycline (20 mg/L). Microbial community analyses suggest that an alternative methanogenic pathway, specifically that of methanol-utilizing methanogens, may be important for ensuring the stability of methane production in the presence of high tetracycline concentrations. In addition, the accumulation of propionate was due to an increase in volatile fatty acids (VFA)-producing bacteria coupled with a reduction in propionate utilizers. An increase in the abundance of tetracycline resistance genes associated with ribosomal protection proteins was observed after 30 days of exposure to high concentrations of tetracycline, while other targeted resistance genes showed no significant changes. These findings suggest that anaerobic treatment processes can robustly treat wastewater with varying concentrations of antibiotics while also deriving value-added products and minimizing the dissemination of associated antibiotic resistance genes.

  8. 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.

  9. 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.

  10. Resistance and tolerance to tropodithietic acid, an antimicrobial in aquaculture, is hard to select.

    Science.gov (United States)

    Porsby, Cisse Hedegaard; Webber, Mark A; Nielsen, Kristian Fog; Piddock, Laura J V; Gram, Lone

    2011-04-01

    The antibacterial compound tropodithietic acid (TDA) is produced by bacteria of the marine Roseobacter clade and is thought to explain the fish probiotic properties of some roseobacters. The aim of the present study was to determine the antibacterial spectrum of TDA and the likelihood of development of TDA resistance. A bacterial extract containing 95% TDA was effective against a range of human-pathogenic bacteria, including both Gram-negative and Gram-positive bacteria. TDA was bactericidal against Salmonella enterica serovar Typhimurium SL1344 and Staphylococcus aureus NCTC 12493 and killed both growing and nongrowing cells. Several experimental approaches were used to select mutants resistant to TDA or subpopulations of strains with enhanced tolerance to TDA. No approach (single exposures to TDA extract administered via different methods, screening of a transposon library for resistant mutants, or prolonged exposure to incremental concentrations of TDA) resulted in resistant or tolerant strains. After more than 300 generations exposed to sub-MIC and MIC concentrations of a TDA-containing extract, strains tolerant to 2× the MIC of TDA for wild-type strains were selected, but the tolerance disappeared after one passage in medium without TDA extract. S. Typhimurium mutants with nonfunctional efflux pump and porin genes had the same TDA susceptibility as wild-type strains, suggesting that efflux pumps and porins are not involved in innate tolerance to TDA. TDA is a promising broad-spectrum antimicrobial in part due to the fact that enhanced tolerance is difficult to gain and that the TDA-tolerant phenotype appears to confer only low-level resistance and is very unstable.

  11. 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.

  12. mRNA biomarkers selection based on Partial Least Square algorithm in order to further predict Bacillus weihenstephanensis acid resistance.

    Science.gov (United States)

    Desriac, Noémie; Coroller, Louis; Jannic, Frederic; Postollec, Florence; Sohier, Danièle

    2015-02-01

    In order to integrate omics data to quantitative microbiological risk assessment in foods, gene expressions may serve as bacterial behaviour biomarkers. In this study an integrative approach encompassing predictive modelling and mRNAs quantifications, was followed to select molecular biomarkers to further predict the acid resistance of Bacillus weihenstephanensis. A multivariate analysis was performed to correlate the acid bacterial resistance and the gene expression of vegetative cells with or without exposure to stressing conditions. This mathematical method provides the advantage to take gene expressions and their interactions into account. The use of the Partial Least Squares algorithm allowed the selection of nine genes as acid resistance biomarkers among thirty targeted genes. According to their involvement in the general acid stress response of Bacillus, these genes were assigned to three different biological modules namely, metabolic rearrangements, general stress response and oxidative stress response. The oxidative stress response appeared as the major activated biological module in B. weihenstephanensis cells submitted to acid stress conditions. Furthermore, as a firstly described model, the developed concept showed promising results to further be used to predict bacterial resistance using gene expression. Thus, this study underlines the possibility to integrate the bacterial physiology state, using omics biomarkers, into bacterial behaviour modelling and provide mechanistic understanding in acid bacterial resistance mechanisms.

  13. Partial characterization of chayotextle starch-based films added with ascorbic acid encapsulated in resistant starch.

    Science.gov (United States)

    Martínez-Ortiz, Miguel A; Vargas-Torres, Apolonio; Román-Gutiérrez, Alma D; Chavarría-Hernández, Norberto; Zamudio-Flores, Paul B; Meza-Nieto, Martín; Palma-Rodríguez, Heidi M

    2017-02-03

    Chayotextle starch was modified by subjecting it to a dual treatment with acid and heating-cooling cycles. This caused a decrease in the content of amylose, which showed values of 30.22%, 4.80%, 3.27% and 3.57% for native chayotextle starch (NCS), starch modified by acid hydrolysis (CMS), and CMS with one (CMS1AC) and three autoclave cycles (CMS3AC), respectively. The percentage of crystallinity showed an increase of 36.9%-62% for NCS and CMS3AC. The highest content of resistant starch (RS) was observed in CMS3AC (37.05%). The microcapsules were made with CMS3AC due to its higher RS content; the total content of ascorbic acid of the microcapsules was 82.3%. The addition of different concentrations of CMS3AC microcapsules (0%, 2.5%, 6.255% and 12.5%) to chayotextle starch-based films (CSF) increased their tensile strength and elastic modulus. The content of ascorbic acid and RS in CSF was ranged from 0% to 59.4% and from 4.84% to 37.05% in the control film and in the film mixed with CMS3AC microcapsules, respectively. Water vapor permeability (WVP) values decreased with increasing concentrations of microcapsules in the films. Microscopy observations showed that higher concentrations of microcapsules caused agglomerations due their poor distribution in the matrix of the films.

  14. Antibacterial activity of 2-alkynoic fatty acids against multidrug-resistant bacteria.

    Science.gov (United States)

    Sanabria-Ríos, David J; Rivera-Torres, Yaritza; Maldonado-Domínguez, Gamalier; Domínguez, Idializ; Ríos, Camille; Díaz, Damarith; Rodríguez, José W; Altieri-Rivera, Joanne S; Ríos-Olivares, Eddy; Cintrón, Gabriel; Montano, Nashbly; Carballeira, Néstor M

    2014-02-01

    The first study aimed at determining the structural characteristics needed to prepare antibacterial 2-alkynoic fatty acids (2-AFAs) was accomplished by synthesizing several 2-AFAs and other analogs in 18-76% overall yields. Among all the compounds tested, the 2-hexadecynoic acid (2-HDA) displayed the best overall antibacterial activity against Gram-positive Staphylococcus aureus (MIC=15.6 μg/mL), Staphylococcus saprophyticus (MIC=15.5 μg/mL), and Bacillus cereus (MIC=31.3 μg/mL), as well as against the Gram-negative Klebsiella pneumoniae (7.8 μg/mL) and Pseudomonas aeruginosa (MIC=125 μg/mL). In addition, 2-HDA displayed significant antibacterial activity against methicillin-resistant S. aureus (MRSA) ATCC 43300 (MIC=15.6 μg/mL) and clinical isolates of MRSA (MIC=3.9 μg/mL). No direct relationship was found between the antibacterial activity of 2-AFAs and their critical micelle concentration (CMC) suggesting that the antibacterial properties of these fatty acids are not mediated by micelle formation. It was demonstrated that the presence of a triple bond at C-2 and the carboxylic acid moiety in 2-AFAs are important for their antibacterial activity. 2-HDA has the potential to be further evaluated for use in antibacterial formulations.

  15. 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.

  16. 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.

  17. Dicarboxylic acids with limited numbers of hydrocarbons stabilize cell membrane and increase osmotic resistance in rat erythrocytes.

    Science.gov (United States)

    Mineo, Hitoshi; Amita, Nozomi; Kawawake, Megumi; Higuchi, Ayaka

    2013-11-01

    We examined the effect of dicarboxylic acids having 0 to 6 hydrocarbons and their corresponding monocarboxylic or tricarboxylic acids in changing the osmotic fragility (OF) in rat red blood cells (RBCs). Malonic, succinic, glutaric and adipic acids, which are dicarboxylic acids with 1, 2, 3 and 4 straight hydrocarbons located between two carboxylic groups, decreased the OF in a concentration-dependent manner. Other long-chain dicarboxylic acids did not change the OF in rat RBCs. The benzoic acid derivatives, isophthalic and terephthalic acids, but not phthalic acid, decreased the OF in a concentration-dependent manner. Benzene-1,2,3-tricarboxylic acid, but not benzene-1,3,5-tricarboxylic acid, also decreased the OF in rat RBCs. On the other hand, monocarboxylic acids possessing 2 to 7 straight hydrocarbons and benzoic acid increased the OF in rat RBCs. In short-chain dicarboxylic acids, a limited number of hydrocarbons between the two carboxylic groups are thought to form a V- or U-shaped structure and interact with phospholipids in the RBC membrane. In benzene dicarboxylic and tricarboxylic acids, a part of benzene nucleus between the two carboxylic groups is thought to enter the plasma membrane and act on acyl-chain in phospholipids in the RBC membrane. For dicarboxylic and tricarboxylic acids, limited numbers of hydrocarbons in molecules are speculated to enter the RBC membrane with the hydrophilic carboxylic groups remaining outside, stabilizing the structure of the cell membrane and resulting in an increase in osmotic resistance in rat RBCs.

  18. Anaerobic lipid degradation through acidification and methanization.

    Science.gov (United States)

    Kim, Ijung; Kim, Sang-Hyoun; Shin, Hang-Sik; Jung, Jin-Young

    2010-01-01

    In biological wastewater treatment high lipid concentration is known to inhibit microorganisms and cause active biomass flotation. To reduce lipid inhibition, a two-phase anaerobic system, consisting of an anaerobic sequencing batch reactor (ASBR) and an upflow anaerobic sludge blanket (UASB) reactor, was applied to synthetic dairy wastewater. During 153 days of operation, the two-phase system showed stable performance in lipid degradation. In the ASBR, a 13% lipid removal efficiency and 10% double bond removal efficiency were maintained. In the UASB, the chemical oxygen demand (COD), lipid and volatile fatty acid (VFA) removal efficiencies were more than 80%, 70% and 95%, respectively, up to organic loading rate 6.5 g COD/L/day. There were no operational problems such as serious scum formation or sludge washout. Protein degradation occurred prior to degradation during acidogenesis.

  19. 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

  20. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  1. 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...

  2. Inhibitory effects of gallic acid ester derivatives on Saccharomyces cerevisiae multidrug resistance protein Pdr5p.

    Science.gov (United States)

    Pereira Rangel, Luciana; Fritzen, Márcio; Yunes, Rosendo Augusto; Leal, Paulo César; Creczynski-Pasa, Tânia Beatriz; Ferreira-Pereira, Antônio

    2010-05-01

    Overexpression of the Saccharomyces cerevisiae ABC transporter Pdr5p confers resistance to a range of structurally unrelated xenobiotics. This property allows Pdr5p to be used as a target for novel multidrug resistance reversal reagents or chemosensitizers. Herein, we report the effects of gallic acid derivatives with substitutions either on the ester moiety or in the benzene ring on the activity of Pdr5p. Compounds with a longer side chain (8-16 carbons) resulted in greater inhibition of Pdr5p ATPase. Derivatives with side chains of 8-12 carbons that retained hydroxyl groups on the benzene ring extensively inhibited Pdr5p ATPase activity. These compounds almost completely inhibited the efflux of the Pdr5p fluorescent substrate Rhodamine 6G and at 25 muM chemosensitized the Pdr5p-overexpressing strain AD124567 to fluconazole (0.4 mg mL(-1)). Gallic acid derivatives may be a new class of Pdr5p inhibitors.

  3. 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

  4. 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

  5. A new steel with good low-temperature sulfuric acid dew point corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, X.Q.; Li, X.G. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Key Laboratory of Corrosion and Protection (Ministry of Education), Beijing (China); Sun, F.L. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Lv, S.J. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Equipment and Power Department, Shijiazhuang Refine and Chemical Company Limited, SINOPEC, Shijiazhuang (China)

    2012-07-15

    In this work, new steels (1, 2, and 3) were developed for low-temperature sulfuric acid dew point corrosion. The mass loss rate, macro- and micro-morphologies and compositions of corrosion products of new steels in 10, 30, and 50% H{sub 2}SO{sub 4} solutions at its corresponding dew points were investigated by immersion test, scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). The results indicated that mass loss rate of all the tested steels first strongly increased and then decreased as H{sub 2}SO{sub 4} concentration increased, which reached maximum at 30%. Corrosion resistance of 2 steel is the best among all specimens due to its fine and homogeneous morphologies of corrosion products. The electrochemical corrosion properties of new steels in 10 and 30% H{sub 2}SO{sub 4} solutions at its corresponding dew points were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that corrosion resistance of 2 steel is the best among all the experimental samples due to its lowest corrosion current density and highest charge transfer resistance, which is consistent with the results obtained from immersion tests. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. The necrotic signal induced by mycophenolic acid overcomes apoptosis-resistance in tumor cells.

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    Gwendaline Guidicelli

    Full Text Available BACKGROUND: The amount of inosine monophosphate dehydrogenase (IMPDH, a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP, is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42. METHODOLOGY/PRINCIPAL FINDINGS: Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA-mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL-overexpressing cells. All tested cells remained sensitive to MPA-mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers. CONCLUSIONS/SIGNIFICANCE: These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells.

  7. Impact of restricted amoxicillin/clavulanic acid use on Escherichia coli resistance--antibiotic DU90% profiles with bacterial resistance rates: a visual presentation.

    Science.gov (United States)

    Mimica Matanovic, Suzana; Bergman, Ulf; Vukovic, Dubravka; Wettermark, Björn; Vlahovic-Palcevski, Vera

    2010-10-01

    High use of amoxicillin/clavulanic acid (AMC) at the University Hospital Osijek (Croatia) contributed to high rates of resistance in Enterobacteriaceae, in particular Escherichia coli (50%). Thus, in order to decrease bacterial resistance, AMC use was restricted. We present results of the restriction on resistance amongst antibiotics accounting for 90% of antibiotic use [drug utilisation 90% (DU90%)]. Data were analysed on antibiotic use and microbiological susceptibility of E. coli during two 9-month periods, before and after the restriction of AMC use. Drug use was presented as numbers of defined daily doses (DDDs) and DDDs/100 bed-days. Resistance of E. coli to antibiotics was presented as percentages of isolated strains in the DU90% segment. Use of AMC was 16 DDDs/100 bed-days or 30% of all antibiotics before the intervention. Use of AMC fell to 2 DDDs/100 bed-days or 4% after the intervention, and resistance of E. coli fell from 37% to 11%. In conclusion, restricted use of AMC resulted in a significant decrease of E. coli resistance. DU90% resistance profiles are simple and useful tools in highlighting problems in antibiotic use and resistance but may also be useful in long-term follow-up of antibiotic policy.

  8. Invited review: anaerobic fermentation of dairy food wastewater.

    Science.gov (United States)

    Hassan, A N; Nelson, B K

    2012-11-01

    Dairy food wastewater disposal represents a major environmental problem. This review discusses microorganisms associated with anaerobic digestion of dairy food wastewater, biochemistry of the process, factors affecting anaerobic digestion, and efforts to develop defined cultures. Anaerobic digestion of dairy food wastewater offers many advantages over other treatments in that a high level of waste stabilization is achieved with much lower levels of sludge. In addition, the process produces readily usable methane with low nutrient requirements and no oxygen. Anaerobic digestion is a series of complex reactions that broadly involve 2 groups of anaerobic or facultative anaerobic microorganisms: acidogens and methanogens. The first group of microorganisms breaks down organic compounds into CO(2) and volatile fatty acids. Some of these organisms are acetogenic, which convert long-chain fatty acids to acetate, CO(2), and hydrogen. Methanogens convert the acidogens' products to methane. The imbalance among the different microbial groups can lead not only to less methane production, but also to process failure. This is due to accumulation of intermediate compounds, such as volatile fatty acids, that inhibit methanogens. The criteria used for evaluation of the anaerobic digestion include levels of hydrogen and volatile fatty acids, methane:carbon ratio, and the gas production rate. A steady state is achieved in an anaerobic digester when the pH, chemical oxygen demand of the effluent, the suspended solids of the effluent, and the daily gas production remain constant. Factors affecting efficiency and stability of the process are types of microorganisms, feed C:N ratio, hydraulic retention time, reactor design, temperature, pH control, hydrogen pressure, and additives such as manure and surfactants. As anaerobic digesters become increasingly used in dairy plants, more research should be directed toward selecting the best cultures that maximize methane production from dairy

  9. 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.

  10. Acid-Breakable Resin-Based Chemical Amplification Positive Resist for Electron-Beam Mastering: Design and Lithographic Performance

    Science.gov (United States)

    Sakamizu, Toshio; Shiraishi, Hiroshi

    2004-07-01

    A positive chemical amplification resist based on acid-catalyzed fragmentation of acetal groups in its main chain has been developed as a means of reducing line-edge roughness. The resist consists of an acid generator, an acid-diffusion controller and an acid-breakable (AB) resin that is synthesized through a co-condensation reaction between polyphenol and aromatic multifunctional vinylether compound. The effects of the fractionation of AB resins on resin properties and line-edge roughness (LER) are evaluated. Although AB resins have wide molecular weight distributions, the density of acetal groups in this AB resin is found to be almost constant except in the lower molecular weight components. The resist with a fractionated resin from which such components are removed provides high-resolution patterns (70-nm-wide pit) with fairly low LER. AFM analysis shows that the surface roughness (SR) of the resist with the fractionated resin is smaller than that of a resist using nonfractionated AB resin, and that the SR value is not altered throughout the range of exposure doses up to just below the start of dissolution. By using the fractionated AB resin, the AB resin-based resist (ABR) is capable of forming sub-100 nm L/S patterns with less than 5 nm of LER (3σ).

  11. Phosphoric acid-etching promotes bond strength and formation of acid-base resistant zone on enamel.

    Science.gov (United States)

    Li, N; Nikaido, T; Alireza, S; Takagaki, T; Chen, J-H; Tagami, J

    2013-01-01

    This study examined the effect of phosphoric acid (PA) etching on the bond strength and acid-base resistant zone (ABRZ) formation of a two-step self-etching adhesive (SEA) system to enamel. An etch-and-rinse adhesive (EAR) system Single Bond (SB) and a two-step SEA system Clearfil SE Bond (SE) were used. Human teeth were randomly divided into four groups according to different adhesive treatments: 1) SB; 2) SE; 3) 35% PA etching→SE primer→SE adhesive (PA/SEp+a); (4) 35% PA etching→SE adhesive (PA/SEa). Microshear bond strength to enamel was measured and then statistically analyzed using one-way analysis of variance and the Tukey honestly significant difference test. The failure mode was recorded and analyzed by χ( 2 ) test. The etching pattern of the enamel surface was observed with scanning electron microscope (SEM). The bonded interface was exposed to a demineralizing solution (pH=4.5) for 4.5 hours and then 5% sodium hypochlorite with ultrasonication for 30 minutes. After argon-ion etching, the interfacial ultrastructure was observed using SEM. The microshear bond strength to enamel of the SE group was significantly lower (p<0.05) than that of the three PA-etched groups, although the latter three were not significantly different from one another. The ABRZ was detected in all the groups. In morphological observation, the ABRZ in the three PA-etched groups were obviously thicker compared with the SE group with an irregular wave-shaped edge.

  12. 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

  13. 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

  14. Isolation and Identification of Alicyclobacillus with High Dipicolinic Acid and Heat Resistant Proteins from Mango Juice

    Directory of Open Access Journals (Sweden)

    Hamid Reza Akhbariyoon

    2016-10-01

    Full Text Available Background and Objectives: Microbial spoilage of juices and industries related with Alicyclobacillus are considerable international issues. This spore-forming bacterium causes changes in juices odor and taste. The isolation and identification of Alicyclobacillus contamination in juice producing and packaging industries has an essential role in the prevention and control of this type of spoilage bacterium in HACCP (Hazard analysis and critical control points manner.Materials and Methods: A thermo-acidophilic, non-pathogenic and sporeforming bacterium was isolated from mango juice. Preliminary identification of the isolates was based on morphological, biochemical and physiological properties. Identification at species level was made by PCR amplification. The influence of temperature in the range of 25-65°C in the growth of bacterium and in the range of 80-120°C in spore-resistant and heat resistant proteins was investigated and compared with other spore producing bacteria.Results and Conclusion: Phylogenetic analysis of the 16S rRNA gene sequencing indicated that the isolated strain constituted a distinct lineage in the Alicyclobacillus cluster and submitted to NCBI with access number Alicyclobacillus HRM-5 KM983424.1. The spores resisted 110°C for 3 h, and produced 28% dipicolinic acid more comparable to Bacillus licheniformis. Also they could produce 0.69 mg heat resistance protein after 1.5 h treatment in 100°C. The results showed that this strain could have biotechnological applications.Conflict of interests: The authors declare no conflict of interest.

  15. 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.

  16. [Production of hydrolases by lactic acid bacteria and bifidobacteria and their antibiotic resistance].

    Science.gov (United States)

    Novik, G I; Astanovich, N I; Riabaia, N E

    2007-01-01

    It was demonstrated that bifidobacteria and lactic acid bacteria B. adolescentis and Lactobacillus sp. synthesized extracellular enzymes cleaving glycoside bonds in the molecules of dextran, pectic acid, and soluble starch. The maximal production of extracellular beta-galactosidase by B. adolescentis 91-BIM and 94-BIM at a rate of 0.08 and 0.03 U/mg h was observed during the exponential growth phase at 5 and 12 h of cultivation, respectively. The cultures of bifidobacteria retained 60-70% of beta-galactosidase and alpha-amylase activities after six months of storage. The bifidobacterium strains studied were resistant to amphotericin and aminoglycosides (gentamicin, kanamycin, and netromycin). The lactam antibiotics (ampicillin, benzylpenicillin, bicillin 3, bicillin 5, and carbenicillin), the preparations inhibiting protein synthesis at the level of ribosomes (lincomycin), RNA polymerase inhibitors (rifampin), cephalosporin, and Maxipime inhibited the growth of bifidobacteria. Rifampin, erythromycin, amphotericin, Maxipime, Fortum, doxycycline, levomycetin, streptomycin, and the aminoglycosides netromycin, gentamicin, and kanamycin did not have an effect on the growth of Lactobacillus sp., whereas semisynthetic derivatives of penicillin, carbenicillin and ampicillin, inhibited its growth as well as Oxamp and lincomycin. The lactam antibiotics benzylpenicillin, bicillin 3, and bicillin 5 inhibited the growth of lactic acid bacilli by 30-90%.

  17. Nanoleakage in Hybrid Layer and Acid-Base Resistant Zone at the Adhesive/Dentin Interface.

    Science.gov (United States)

    Nikaido, Toru; Nurrohman, Hamid; Takagaki, Tomohiro; Sadr, Alireza; Ichinose, Shizuko; Tagami, Junji

    2015-10-01

    The aim of interfacial nanoleakage evaluation is to gain a better understanding of degradation of the adhesive-dentin interface. The acid-base resistant zone (ABRZ) is recognized at the bonded interface under the hybrid layer (HL) in self-etch adhesive systems after an acid-base challenge. The purpose of this study was to evaluate nanoleakage in HL and ABRZ using three self-etch adhesives; Clearfil SE Bond (SEB), Clearfil SE One (SEO), and G-Bond Plus (GBP). One of the three adhesives was applied on the ground dentin surface and light cured. The specimens were longitudinally divided into two halves. One half remained as the control group. The others were immersed in ammoniacal silver nitrate solution, followed by photo developing solution under fluorescent light. Following this, the specimens were subjected to acid-base challenges with an artificial demineralization solution (pH4.5) and sodium hypochlorite, and prepared in accordance with common procedures for transmission electron microscopy (TEM) examination. The TEM images revealed silver depositions in HL and ABRZ due to nanoleakage in all the adhesives; however, the extent of nanoleakage was material dependent. Funnel-shaped erosion beneath the ABRZ was observed only in the all-in-one adhesive systems; SEO and GBP, but not in the two-step self-etch adhesive system; SEB.

  18. Effects of Organic Acids Addition on the Anaerobic Fermentation of Glycerol by Klebsiella Pneumoniae%有机酸对肺炎克雷伯杆菌厌氧代谢甘油的影响

    Institute of Scientific and Technical Information of China (English)

    薛学东; 李伟; 李志敏; 周利; 夏月兰; 叶勤

    2011-01-01

    在肺炎克雷伯杆菌厌氧发酵甘油生产1,3-丙二醇的过程中,大量的副产物,特别是乳酸和乙醇等副产物的生成,导致1,3-丙二醇的浓度和得率下降.为了进一步了解有机酸加入后菌体的代谢情况,在菌体生长期同时加入柠檬酸、琥珀酸和延胡索酸三种有机酸的混合液,使其浓度达到3.8 mmol.L-1·5L罐发酵结果显示,产物的生成发生显著变化.同时,发酵动力学分析表明,有机酸加入后,甘油的比消耗速率和1,3-丙二醇的比生成速率显著提高,而乳酸和乙醇的比生成速率则明显下降.进一步对甘油代谢过程中的碳流分配分析表明,有机酸加入后,甘油进入还原途径的碳流比例由0.45显著增加为0.62,氧化途径的碳流比例由0.53减为0.35.%During the anaerobic fermentation of glycerol to produce 1,3-propanediol by Klebsiella pneumoniae, a lot of by-products (especially lactic acid and ethanol) are formed simultaneously, which lowers the final 1,3-propanediol concentration in the fermentation liquid and the yield of 1,3-propanediol. In order to get the further information of cell metabolism with organic acids addition, the anaerobic fed-back fermentation of glycerol with addition of organic acid mixture (mixture of citrate, succinate and fumarate acids, the concentration of each acid is 3.8 mmol·L-1) in the cell growth period was conducted in a 5 L reactor. The results show that the formation of the products changes significantly when the organic acid mixture was added. At the same time, the kinetic performance analysis of the fermentation indicates that, with the addition of the organic acid mixture, the specific rates of glycerol consumption and 1,3-propanediol formation increase significantly, while the specific formation rates of lactic acid and ethanol decrease sharply. The further analysis of the total carbon flow distribution of glycerol metabolism indicates that, with the addition of the organic acid mixture

  19. 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

  20. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen

    2009-03-01

    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  1. Pre-harvest application of oxalic acid increases quality and resistance to Penicillium expansum in kiwifruit during postharvest storage.

    Science.gov (United States)

    Zhu, Yuyan; Yu, Jie; Brecht, Jeffrey K; Jiang, Tianjia; Zheng, Xiaolin

    2016-01-01

    Kiwifruit (Actinidia deliciosa cv. Bruno) fruits were sprayed with 5mM oxalic acid (OA) at 130, 137, and 144 days after full blossom, and then harvested at commercial maturity [soluble solid content (SSC) around 10.0%] and stored at room temperature (20 ± 1 °C). Pre-harvest application of OA led to fruit with higher ascorbic acid content at harvest, slowed the decreases in fruit firmness and ascorbic acid content and increase in SSC during storage, and also decreased the natural disease incidence, lesion diameter, and patulin accumulation in fruit inoculated with Penicillium expansum, indicating that the OA treatment increased quality and induced disease resistance in kiwifruit. It was suggested that the increase in activities of defense-related enzymes and in levels of substances related to disease resistance might collectively contribute to resistance in kiwifruit against fungi such as P. expansum in storage.

  2. Effects of Peracetic Acid on the Corrosion Resistance of Commercially Pure Titanium (grade 4).

    Science.gov (United States)

    Raimundo, Lariça B; Orsi, Iara A; Kuri, Sebastião E; Rovere, Carlos Alberto D; Busquim, Thaís P; Borie, Eduardo

    2015-01-01

    The aim of this study was to evaluate the corrosion resistance of pure titanium grade 4 (cp-Ti-4), subjected to disinfection with 0.2% and 2% peracetic acid during different immersion periods using anodic potentiodynamic polarization test in acid and neutral artificial saliva. Cylindrical samples of cp-Ti-4 (5 mm x 5 mm) were used to fabricate 24 working electrodes, which were mechanically polished and divided into eight groups (n=3) for disinfection in 2% and 0.2% peracetic acid for 30 and 120 min. After disinfection, anodic polarization was performed in artificial saliva with pH 4.8 and 6.8 to assess the electrochemical behavior of the electrodes. A conventional electrochemical cell, constituting a reference electrode, a platinum counter electrode, and the working electrode (cp-Ti specimens) were used with a scanning rate of 1 mV/s. Three curves were obtained for each working electrode, and corrosion was characterized by using scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Data of corrosion potential (Ecorr) and passive current (Ipass) obtained by the polarization curves were analyzed statistically by Student's t-test (a=0.05). The statistical analysis showed no significant differences (p>0.05) between artificial saliva types at different concentrations and periods of disinfection, as well as between control and experimental groups. No surface changes were observed in all groups evaluated. In conclusion, disinfection with 0.2% and 2% peracetic acid concentrations did not cause corrosion in samples manufactured with cp-Ti-4.

  3. Nordihydroguaiaretic acid enhances the activities of aminoglycosides against methicillin- sensitive and resistant Staphylococcus aureus in vitro and in vivo

    OpenAIRE

    Edward eCunningham-Oakes; Odel eSoren; Caroline eMoussa; Getika eRathor; Yingjun eLiu; Anthony eCoates; Yanmin eHu

    2015-01-01

    Infections caused by methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) are prevalent. MRSA infections are difficult to treat and there are no new classes of antibiotics produced to the market to treat infections caused by the resistant bacteria. Therefore, using antibiotic enhancers to rescue existing classes of antibiotics is an attractive strategy. Nordihydroguaiaretic acid (NDGA) is an antioxidant compound found in extracts from plant Larrea Tridentata. ...

  4. Nordihydroguaiaretic acid enhances the activities of aminoglycosides against methicillin- sensitive and resistant Staphylococcus aureus in vitro and in vivo

    OpenAIRE

    Cunningham-Oakes, Edward; Soren, Odel; Moussa, Caroline; Rathor, Getika; Liu, Yingjun; Coates, Anthony; Hu, Yanmin

    2015-01-01

    Infections caused by methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are prevalent. MRSA infections are difficult to treat and there are no new classes of antibiotics produced to the market to treat infections caused by the resistant bacteria. Therefore, using antibiotic enhancers to rescue existing classes of antibiotics is an attractive strategy. Nordihydroguaiaretic acid (NDGA) is an antioxidant compound found in extracts from plant Larrea Trid...

  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. Impact of fertilizing with raw or anaerobically digested sewage sludge on the abundance of antibiotic-resistant coliforms, antibiotic resistance genes, and pathogenic bacteria in soil and on vegetables at harvest.

    Science.gov (United States)

    Rahube, Teddie O; Marti, Romain; Scott, Andrew; Tien, Yuan-Ching; Murray, Roger; Sabourin, Lyne; Zhang, Yun; Duenk, Peter; Lapen, David R; Topp, Edward

    2014-11-01

    The consumption of crops fertilized with human waste represents a potential route of exposure to antibiotic-resistant fecal bacteria. The present study evaluated the abundance of bacteria and antibiotic resistance genes by using both culture-dependent and molecular methods. Various vegetables (lettuce, carrots, radish, and tomatoes) were sown into field plots fertilized inorganically or with class B biosolids or untreated municipal sewage sludge and harvested when of marketable quality. Analysis of viable pathogenic bacteria or antibiotic-resistant coliform bacteria by plate counts did not reveal significant treatment effects of fertilization with class B biosolids or untreated sewage sludge on the vegetables. Numerous targeted genes associated with antibiotic resistance and mobile genetic elements were detected by PCR in soil and on vegetables at harvest from plots that received no organic amendment. However, in the season of application, vegetables harvested from plots treated with either material carried gene targets not detected in the absence of amendment. Several gene targets evaluated by using quantitative PCR (qPCR) were considerably more abundant on vegetables harvested from sewage sludge-treated plots than on vegetables from control plots in the season of application, whereas vegetables harvested the following year revealed no treatment effect. Overall, the results of the present study suggest that producing vegetable crops in ground fertilized with human waste without appropriate delay or pretreatment will result in an additional burden of antibiotic resistance genes on harvested crops. Managing human exposure to antibiotic resistance genes carried in human waste must be undertaken through judicious agricultural practice.

  7. 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.

  8. Spontaneous bacteriocin resistance in Listeria monocytogenes as a susceptibility screen for identifying different mechanisms of resistance and modes of action by bacteriocins of lactic acid bacteria.

    Science.gov (United States)

    Macwana, Sunita; Muriana, Peter M

    2012-01-01

    A practical system was devised for grouping bacteriocins of lactic acid bacteria (LAB) based on mode of action as determined by changes in inhibitory activity to spontaneously-acquired bacteriocin resistance (Bac(R)). Wild type Listeria monocytogenes 39-2 was sensitive to five bacteriocins produced by 3 genera of LAB: pediocin PA-1 and pediocin Bac3 (Pediococcus), lacticin FS97 and lacticin FS56 (Lactococcus), and curvaticin FS47 (Lactobacillus). A spontaneous Bac(R) derivative of L. monocytogenes 39-2 obtained by selective recovery against lacticin FS56 provided complete resistance to the bacteriocin made by Lactococcus lactis FS56. The lacticin FS56-resistant strain of L. monocyotgenes 39-2 was also cross-resistant to curvaticin FS47 and pediocin PA-1, but not to lacticin FS97 or pediocin Bac3. The same pattern of cross-resistance was also observed with Bac(R) isolates obtained with L. monocytogenes Scott A-2. A spontaneous mutation that renders a strain cross-resistant to different bacteriocins indicates that they share a common mechanism of resistance due to similar modes of action of the bacteriocins. Spontaneous resistance was acquired to other bacteriocins (in aggregate) by following the same procedure against which the Bac(R) strain was still sensitive. In subsequent challenge assays, mixtures of bacteriocins of different modes of action provided greater inhibition than mixtures of bacteriocins of the same mode of action (as determined by our screening method). This study identifies a methodical approach to classify bacteriocins into functional groups based on mechanism of resistance (i.e., mode of action) that could be used for identifying the best mixture of bacteriocins for use as biopreservatives.

  9. 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

  10. 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.

  11. 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.

  12. Lipoteichoic acid synthesis inhibition in combination with antibiotics abrogates growth of multidrug-resistant Enterococcus faecium.

    Science.gov (United States)

    Paganelli, Fernanda L; van de Kamer, Tim; Brouwer, Ellen C; Leavis, Helen L; Woodford, Neil; Bonten, Marc J M; Willems, Rob J L; Hendrickx, Antoni P A

    2017-03-01

    Enterococcus faecium is a multidrug-resistant (MDR) nosocomial pathogen causing significant morbidity in debilitated patients. New antimicrobials are needed to treat antibiotic-resistant E. faecium infections in hospitalised patients. E. faecium incorporates lipoteichoic acid (LTA) (1,3-polyglycerol-phosphate linked to glycolipid) in its cell wall. The small-molecule inhibitor 1771 [2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate] specifically blocks the activity of Staphylococcus aureus LtaS synthase, which polymerises 1,3-glycerolphosphate into LTA polymers. Here we characterised the effects of the small-molecule inhibitor 1771 on the growth of E. faecium isolates, alone (28 strains) or in combination with the antibiotics vancomycin, daptomycin, ampicillin, gentamicin or linezolid (15 strains), and on biofilm formation (16 strains). Inhibition of LTA synthesis at the surface of the cell by compound 1771 in combination with current antibiotic therapy abrogates enterococcal growth in vitro but does not affect mature E. faecium biofilms. Targeting LTA synthesis may provide new possibilities to treat MDR E. faecium infections.

  13. Acyl Ghrelin Induces Insulin Resistance Independently of GH, Cortisol, and Free Fatty Acids

    Science.gov (United States)

    Vestergaard, Esben T.; Jessen, Niels; Møller, Niels; Jørgensen, Jens Otto Lunde

    2017-01-01

    Ghrelin produced in the gut stimulates GH and ACTH secretion from the pituitary and also stimulates appetite and gastric emptying. We have shown that ghrelin also induces insulin resistance via GH-independent mechanisms, but it is unknown if this effect depends on ambient fatty acid (FFA) levels. We investigated the impact of ghrelin and pharmacological antilipolysis (acipimox) on insulin sensitivity and substrate metabolism in 8 adult hypopituitary patients on stable replacement with GH and hydrocortisone using a 2 × 2 factorial design: Ghrelin infusion, saline infusion, ghrelin plus short-term acipimox, and acipimox alone. Peripheral and hepatic insulin sensitivity was determined with a hyperinsulinemic euglycemic clamp in combination with a glucose tracer infusion. Insulin signaling was assayed in muscle biopsies. Peripheral insulin sensitivity was reduced by ghrelin independently of ambient FFA concentrations and was increased by acipimox independently of ghrelin. Hepatic insulin sensitivity was increased by acipimox. Insulin signaling pathways in skeletal muscle were not consistently regulated by ghrelin. Our data demonstrate that ghrelin induces peripheral insulin resistance independently of GH, cortisol, and FFA. The molecular mechanisms remain elusive, but we speculate that ghrelin is a hitherto unrecognized direct regulator of substrate metabolism. We also suggest that acipimox per se improves hepatic insulin sensitivity. PMID:28198428

  14. 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.

  15. Hypochlorous acid via peroxynitrite activates protein kinase Cθ and insulin resistance in adipocytes.

    Science.gov (United States)

    Zhou, Jun; Wang, Qilong; Ding, Ye; Zou, Ming-Hui

    2015-02-01

    We recently reported that genetic deletion of myeloperoxidase (MPO) alleviates obesity-related insulin resistance in mice in vivo. How MPO impairs insulin sensitivity in adipocytes is poorly characterized. As hypochlorous acid (HOCl) is a principal oxidant product generated by MPO, we evaluated the effects of HOCl on insulin signaling in adipocytes differentiated from 3T3-L1 cells. Exposure of 3T3-L1 adipocytes to exogenous HOCl (200 μmol/l) attenuated insulin-stimulated 2-deoxyglucose uptake, GLUT4 translocation, and insulin signals, including tyrosine phosphorylation of insulin receptor substrate 1 (IRS1) and phosphorylation of Akt. Furthermore, treatment with HOCl induced phosphorylation of IRS1 at serine 307, inhibitor κB kinase (IKK), c-Jun NH2-terminal kinase (JNK), and phosphorylation of PKCθ (PKCθ). In addition, genetic and pharmacological inhibition of IKK and JNK abolished serine phosphorylation of IRS1 and impairment of insulin signaling by HOCl. Furthermore, knockdown of PKCθ using siRNA transfection suppressed phosphorylation of IKK and JNK and consequently attenuated the HOCl-impaired insulin signaling pathway. Moreover, activation of PKCθ by peroxynitrite was accompanied by increased phosphorylation of IKK, JNK, and IRS1-serine 307. In contrast, ONOO(-) inhibitors abolished HOCl-induced phosphorylation of PKCθ, IKK, JNK, and IRS1-serine 307, as well as insulin resistance. Finally, high-fat diet (HFD)-induced insulin resistance was associated with enhanced phosphorylation of PKCθ, IKK, JNK, and IRS1 at serine 307 in white adipose tissues from WT mice, all of which were not found in Mpo knockout mice fed HFDs. We conclude that HOCl impairs insulin signaling pathway by increasing ONOO(-) mediated phosphorylation of PKCθ, resulting in phosphorylation of IKK/JNK and consequent serine phosphorylation of IRS1 in adipocytes.

  16. 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.

  17. L-Ascorbic acid can abrogate SVCT-2-dependent cetuximab resistance mediated by mutant KRAS in human colon cancer cells.

    Science.gov (United States)

    Jung, Soo-A; Lee, Dae-Hee; Moon, Jai-Hee; Hong, Seung-Woo; Shin, Jae-Sik; Hwang, Ih Yeon; Shin, Yu Jin; Kim, Jeong Hee; Gong, Eun-Yeung; Kim, Seung-Mi; Lee, Eun Young; Lee, Seul; Kim, Jeong Eun; Kim, Kyu-Pyo; Hong, Yong Sang; Lee, Jung Shin; Jin, Dong-Hoon; Kim, TaeWon; Lee, Wang Jae

    2016-06-01

    Colon cancer patients with mutant KRAS are resistant to cetuximab, an antibody directed against the epidermal growth factor receptor, which is an effective clinical therapy for patients with wild-type KRAS. Numerous combinatorial therapies have been tested to overcome the resistance to cetuximab. However, no combinations have been found that can be used as effective therapeutic strategies. In this study, we demonstrate that L-ascorbic acid partners with cetuximab to induce killing effects, which are influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human colon cancer cells with a mutant KRAS. L-Ascorbic acid treatment of human colon cancer cells that express a mutant KRAS differentially and synergistically induced cell death with cetuximab in a SVCT-2-dependent manner. The ectopic expression of SVCT-2 induced sensitivity to L-ascorbic acid treatment in human colon cancer cells that do not express SVCT-2, whereas the knockdown of endogenous SVCT-2 induced resistance to L-ascorbic acid treatment in SVCT-2-positive cells. Moreover, tumor regression via the administration of L-ascorbic acid and cetuximab in mice bearing tumor cell xenografts corresponded to SVCT-2 protein levels. Interestingly, cell death induced by the combination of L-ascorbic acid and cetuximab resulted in both apoptotic and necrotic cell death. These cell death mechanisms were related to a disruption of the ERK pathway and were represented by the impaired activation of RAFs and the activation of the ASK-1-p38 pathway. Taken together, these results suggest that resistance to cetuximab in human colon cancer patients with a mutant KRAS can be bypassed by L-ascorbic acid in an SVCT-2-dependent manner. Furthermore, SVCT-2 in mutant KRAS colon cancer may act as a potent marker for potentiating L-ascorbic acid co-treatment with cetuximab.

  18. Anaerobic degradation of linear alkylbenzene sulfonate.

    Science.gov (United States)

    Mogensen, Anders S; Haagensen, Frank; Ahring, Birgitte K

    2003-04-01

    Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C12 LAS), which show that C12 LAS was biodegradable under methanogenic conditions. Sorption of C12 LAS on sewage sludge was described with a Freundlich isotherm. The C12 LAS sorption was determined with different concentrations of total solids (TS). In the semi-continuously stirred tank reactor, 18% of the added C12 LAS was bioavailable and 20% was biotransformed when spiking with 100 mg/L of C12 LAS and a TS concentration of 14.2 mg/L. Enhanced bioavailability of C12 LAS was obtained in an upflow anaerobic sludge blanket (UASB) reactor inoculated with granular sludge and sewage sludge. Biodegradation under thermophilic conditions was 37% with LAS as sole carbon source. Benzaldehyde was produced in the UASB reactor during LAS transformation.

  19. 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...

  20. Resistance to herbicides caused by single amino acid mutations in acetyl-CoA carboxylase in resistant populations of grassy weeds.

    Science.gov (United States)

    Jang, SoRi; Marjanovic, Jasmina; Gornicki, Piotr

    2013-03-01

    Eleven spontaneous mutations of acetyl-CoA carboxylase have been identified in many herbicide-resistant populations of 42 species of grassy weeds, hampering application of aryloxyphenoxypropionate, cyclohexadione and phenylpyrazoline herbicides in agriculture. IC(50) shifts (resistance indices) caused by herbicide-resistant mutations were determined using a recombinant yeast system that allows comparison of the effects of single amino acid mutations in the same biochemical background, avoiding the complexity inherent in the in planta experiments. The effect of six mutations on the sensitivity of acetyl-CoA carboxylase to nine herbicides representing the three chemical classes was studied. A combination of partially overlapping binding sites of the three classes of herbicides and the structure of their variable parts explains cross-resistance among and between the three classes of inhibitors, as well as differences in their specificity. Some degree of resistance was detected for 51 of 54 herbicide/mutation combinations. Introduction of new herbicides targeting acetyl-CoA carboxylase will depend on their ability to overcome the high degree of cross-resistance already existing in weed populations.

  1. 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.

  2. 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.

  3. 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.

  4. Clinical outcomes in typhoid fever: adverse impact of infection with nalidixic acid-resistant Salmonella typhi

    Directory of Open Access Journals (Sweden)

    Kabra SK

    2005-05-01

    Full Text Available Abstract Background Widespread use of fluoroquinolones has resulted in emergence of Salmonella typhi strains with decreased susceptibility to fluoroquinolones. These strains are identifiable by their nalidixic acid-resistance. We studied the impact of infection with nalidixic acid-resistant S. typhi (NARST on clinical outcomes in patients with bacteriologically-confirmed typhoid fever. Methods Clinical and laboratory features, fever clearance time and complications were prospectively studied in patients with blood culture-proven typhoid fever, treated at a tertiary care hospital in north India, during the period from November 2001 to October 2003. Susceptibility to amoxycillin, co-trimoxazole, chloramphenicol, ciprofloxacin and ceftriaxone were tested by disc diffusion method. Minimum inhibitory concentrations (MIC of ciprofloxacin and ceftriaxone were determined by E-test method. Results During a two-year period, 60 patients (age [mean ± SD]: 15 ± 9 years; males: 40 [67%] were studied. All isolates were sensitive to ciprofloxacin and ceftriaxone by disc diffusion and MIC breakpoints. However, 11 patients had clinical failure of fluoroquinolone therapy. Infections with NARST isolates (47 [78%] were significantly associated with longer duration of fever at presentation (median [IQR] 10 [7-15] vs. 4 [3-6] days; P = 0.000, higher frequency of hepatomegaly (57% vs. 15%; P = 0.021, higher levels of aspartate aminotransferase (121 [66–235] vs. 73 [44–119] IU/L; P = 0.033, and increased MIC of ciprofloxacin (0.37 ± 0.21 vs. 0.17 ± 0.14 μg/mL; P = 0.005, as compared to infections with nalidixic acid-susceptible isolates. All 11 patients with complications were infected with NARST isolates. Total duration of illness was significantly longer in patients who developed complications than in patients who did not (22 [14.8–32] vs. 12 [9.3–20.3] days; P = 0.011. Duration of prior antibiotic intake had a strong positive correlation with the

  5. Clinical outcomes in typhoid fever: adverse impact of infection with nalidixic acid-resistant Salmonella typhi

    Science.gov (United States)

    Kadhiravan, Tamilarasu; Wig, Naveet; Kapil, Arti; Kabra, SK; Renuka, K; Misra, Anoop

    2005-01-01

    Background Widespread use of fluoroquinolones has resulted in emergence of Salmonella typhi strains with decreased susceptibility to fluoroquinolones. These strains are identifiable by their nalidixic acid-resistance. We studied the impact of infection with nalidixic acid-resistant S. typhi (NARST) on clinical outcomes in patients with bacteriologically-confirmed typhoid fever. Methods Clinical and laboratory features, fever clearance time and complications were prospectively studied in patients with blood culture-proven typhoid fever, treated at a tertiary care hospital in north India, during the period from November 2001 to October 2003. Susceptibility to amoxycillin, co-trimoxazole, chloramphenicol, ciprofloxacin and ceftriaxone were tested by disc diffusion method. Minimum inhibitory concentrations (MIC) of ciprofloxacin and ceftriaxone were determined by E-test method. Results During a two-year period, 60 patients (age [mean ± SD]: 15 ± 9 years; males: 40 [67%]) were studied. All isolates were sensitive to ciprofloxacin and ceftriaxone by disc diffusion and MIC breakpoints. However, 11 patients had clinical failure of fluoroquinolone therapy. Infections with NARST isolates (47 [78%]) were significantly associated with longer duration of fever at presentation (median [IQR] 10 [7-15] vs. 4 [3-6] days; P = 0.000), higher frequency of hepatomegaly (57% vs. 15%; P = 0.021), higher levels of aspartate aminotransferase (121 [66–235] vs. 73 [44–119] IU/L; P = 0.033), and increased MIC of ciprofloxacin (0.37 ± 0.21 vs. 0.17 ± 0.14 μg/mL; P = 0.005), as compared to infections with nalidixic acid-susceptible isolates. All 11 patients with complications were infected with NARST isolates. Total duration of illness was significantly longer in patients who developed complications than in patients who did not (22 [14.8–32] vs. 12 [9.3–20.3] days; P = 0.011). Duration of prior antibiotic intake had a strong positive correlation with the duration of fever at

  6. Impact of the E540V amino acid substitution in GyrB of Mycobacterium tuberculosis on quinolone resistance.

    Science.gov (United States)

    Kim, Hyun; Nakajima, Chie; Yokoyama, Kazumasa; Rahim, Zeaur; Kim, Youn Uck; Oguri, Hiroki; Suzuki, Yasuhiko

    2011-08-01

    Amino acid substitutions conferring resistance to quinolones in Mycobacterium tuberculosis have generally been found within the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase (GyrA) rather than the B subunit of DNA gyrase (GyrB). To clarify the contribution of an amino acid substitution, E540V, in GyrB to quinolone resistance in M. tuberculosis, we expressed recombinant DNA gyrases in Escherichia coli and characterized them in vitro. Wild-type and GyrB-E540V DNA gyrases were reconstituted in vitro by mixing recombinant GyrA and GyrB. Correlation between the amino acid substitution and quinolone resistance was assessed by the ATP-dependent DNA supercoiling assay, quinolone-inhibited supercoiling assay, and DNA cleavage assay. The 50% inhibitory concentrations of eight quinolones against DNA gyrases bearing the E540V amino acid substitution in GyrB were 2.5- to 36-fold higher than those against the wild-type enzyme. Similarly, the 25% maximum DNA cleavage concentrations were 1.5- to 14-fold higher for the E540V gyrase than for the wild-type enzyme. We further demonstrated that the E540V amino acid substitution influenced the interaction between DNA gyrase and the substituent(s) at R-7, R-8, or both in quinolone structures. This is the first detailed study of the contribution of the E540V amino acid substitution in GyrB to quinolone resistance in M. tuberculosis.

  7. 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.

  8. Putrescine production via the ornithine decarboxylation pathway improves the acid stress survival of Lactobacillus brevis and is part of a horizontally transferred acid resistance locus.

    Science.gov (United States)

    Romano, Andrea; Ladero, Victor; Alvarez, Miguel A; Lucas, Patrick M

    2014-04-03

    Decarboxylation pathways are widespread among lactic acid bacteria; their physiological role is related to acid resistance through the regulation of the intracellular pH and to the production of metabolic energy via the generation of a proton motive force and its conversion into ATP. These pathways include, among others, biogenic amine (BA) production pathways. BA accumulation in foodstuffs is a health risk; thus, the study of the factors involved in their production is of major concern. The analysis of several lactic acid bacterial strains isolated from different environments, including fermented foods and beverages, revealed that the genes encoding these pathways are clustered on the chromosome, which suggests that these genes are part of a genetic hotspot related to acid stress resistance. Further attention was devoted to the ornithine decarboxylase pathway, which affords putrescine from ornithine. Studies were performed on three lactic acid bacteria belonging to different species. The ODC pathway was always shown to be involved in cytosolic pH alkalinisation and acid shock survival, which were observed to occur with a concomitant increase in putrescine production.

  9. 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.

  10. Study of wet etching thin films of indium tin oxide in oxalic acid by monitoring the resistance

    Energy Technology Data Exchange (ETDEWEB)

    Mammana, Suelene S., E-mail: ssmammana@abinfo.com.br [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil); Greatti, Alessandra; Luiz, Francis H.; Costa, Francisca I. da; Mammana, Alaide P. [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil); Calligaris, Guilherme A.; Cardoso, Lisandro P. [Institute of Physics Gleb Wataghin, State University of Campinas-UNICAMP, CEP 13083-859, Campinas, SP (Brazil); Mammana, Carlos I.Z.; Engelsen, Daniel den [Brazilian Association for Informatics - ABINFO, Rua Deusdete Martins Gomes 163, CEP 13084-723, Campinas, SP (Brazil)

    2014-09-30

    We describe a study on wet etching of thin films of indium tin oxide (ITO) using a simple method by monitoring the resistance of the thin film in aqueous solutions of oxalic acid and hydrochloric acid. Generally three different regimes can be distinguished during etching ITO in acids: (1) initial etching, which is slow, (2) a fast etching phase and (3) slow etching stage at the end. These regimes are explained in terms of a porosity–roughness model. This porosity model has been confirmed largely by X-ray reflection measurements at grazing incidence, roughness measurements and scanning electron microscopy (SEM). A reliable method for monitoring the resistance during etching has been developed. This method is based on a 2-strips measuring jig with a very low series contact resistance. The activation energy of the etch rate of ITO films was found to be 80 ± 5 kJ/mol for oxalic acid and 56 ± 5 kJ/mol for HCl. SEM analyses in the final stage of the etching process indicate an enrichment of Sn in the residual film material. These observations are explained in terms of preferential etching of In{sub 2}O{sub 3}. X-ray analyses showed that the density of the ITO film decreased by etching. By adding ferric chloride to the oxalic acid solution we could accelerate the etch rate substantially. - Highlights: • Etching of indium tin oxide thin films by monitoring the resistance. • Oxalic acid has 2–3 times lower etch rate than concentrated HCl. • The etch rate in oxalic acid can be accelerated substantially by adding FeCl{sub 3}. • The proposed etching model for indium tin oxide was confirmed by X-ray analysis and scanning electron microscopy. • Energy Dispersive X-ray Spectroscopy analyses showed preferential etching of In{sub 2}O{sub 3}, enriching the film with SnO{sub 2}.

  11. Antibiotic resistance and multidrug-resistant efflux pumps expression in lactic acid bacteria isolated from pozol, a nonalcoholic Mayan maize fermented beverage.

    Science.gov (United States)

    Wacher-Rodarte, Maria Del Carmen; Trejo-Muñúzuri, Tanya Paulina; Montiel-Aguirre, Jesús Fernando; Drago-Serrano, Maria Elisa; Gutiérrez-Lucas, Raúl L; Castañeda-Sánchez, Jorge Ismael; Sainz-Espuñes, Teresita

    2016-05-01

    Pozol is a handcrafted nonalcoholic Mayan beverage produced by the spontaneous fermentation of maize dough by lactic acid bacteria. Lactic acid bacteria (LAB) are carriers of chromosomal encoded multidrug-resistant efflux pumps genes that can be transferred to pathogens and/or confer resistance to compounds released during the fermentation process causing food spoiling. The aim of this study was to evaluate the antibiotic sensibility and the transcriptional expression of ABC-type efflux pumps in LAB isolated from pozol that contributes to multidrug resistance. Analysis of LAB and Staphylococcus (S.) aureus ATCC 29213 and ATCC 6538 control strains to antibiotic susceptibility, minimal inhibitory concentration (MIC), and minimal bactericidal concentration (MBC) to ethidium bromide were based in "standard methods" whereas the ethidium bromide efflux assay was done by fluorometric assay. Transcriptional expression of efflux pumps was analyzed by RT-PCR. LAB showed antibiotic multiresistance profiles, moreover, Lactococcus (L.) lactis and Lactobacillus (L.) plantarum displayed higher ethidium bromide efflux phenotype than S. aureus control strains. Ethidium bromide resistance and ethidium bromide efflux phenotypes were unrelated with the overexpression of lmrD in L. lactics, or the underexpression of lmrA in L. plantarum and norA in S. aureus. These findings suggest that, moreover, the analyzed efflux pumps genes, other unknown redundant mechanisms may underlie the antibiotic resistance and the ethidium bromide efflux phenotype in L. lactis and L. plantarum. Phenotypic and molecular drug multiresistance assessment in LAB may improve a better selection of the fermentation starter cultures used in pozol, and to control the antibiotic resistance widespread and food spoiling for health safety.

  12. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  13. Systemic resistance in citrus to Tetranychus urticae induced by conspecifics is transmitted by grafting and mediated by mobile amino acids.

    Science.gov (United States)

    Agut, Blas; Gamir, Jordi; Jaques, Josep A; Flors, Victor

    2016-10-01

    Recent research suggests that systemic signalling and communication between roots and leaves plays an important role in plant defence against herbivores. In the present study, we show that the oviposition of the two-spotted spider mite Tetranychus urticae in the systemic leaves of citrus rootstock Citrus aurantium (sour orange) was reduced by 50% when a lower leaf was previously infested with conspecifics. Metabolomic and gene expression analysis of the root efflux revealed a strong accumulation of glutamic acid (Glu) that triggered the expression of the citrus putative glutamate receptor (GRL) in the shoots. Additionally, uninfested sour orange systemic leaves showed increased expression of glutamate receptors and higher amounts of jasmonic acid (JA) and 12-oxo-phytodienoic acid in plants that were previously infested. Glu perception in the shoots induced the JA pathway, which primed LOX-2 gene expression when citrus plants were exposed to a second infestation. The spider mite-susceptible citrus rootstock Cleopatra mandarin (C. unshiu) also expressed systemic resistance, although the resistance was less effective than the resistance in sour orange. Surprisingly, the mobile signal in Cleopatra mandarin was not Glu, which suggests a strong genotype-dependency for systemic signalling in citrus. When the cultivar Clemenules (C. clementina) was grafted onto sour orange, there was a reduction in symptomatic leaves and T. urticae populations compared to the same cultivar grafted onto Cleopatra mandarin. Thus, systemic resistance is transmitted from the roots to the shoots in citrus and is dependent on rootstock resistance.

  14. Mixed species biofilms of Listeria monocytogenes and Lactobacillus plantarum show enhanced resistance to benzalkonium chloride and peracetic acid

    NARCIS (Netherlands)

    Veen, van der S.; Abee, T.

    2011-01-01

    We investigated the formation of single and mixed species biofilms of Listeria monocytogenes strains EGD-e and LR-991, with Lactobacillus plantarum WCFS1 as secondary species, and their resistance to the disinfectants benzalkonium chloride and peracetic acid. Modulation of growth, biofilm formation,

  15. 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...

  16. 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

  17. Nicotiflorin, rutin and chlorogenic acid: phenylpropanoids involved differently in quantitative resistance of potato tubers to biotrophic and necrotrophic pathogens.

    Science.gov (United States)

    Kröner, Alexander; Marnet, Nathalie; Andrivon, Didier; Val, Florence

    2012-08-01

    Physiological and molecular mechanisms underlying quantitative resistance of plants to pathogens are still poorly understood, but could depend upon differences in the intensity or timing of general defense responses. This may be the case for the biosynthesis of phenolics which are known to increase after elicitation by pathogens. We thus tested the hypothesis that differences in quantitative resistance were related to differential induction of phenolics by pathogen-derived elicitors. Five potato cultivars (Solanum tuberosum, L.) spanning a range of quantitative resistance were treated with a concentrated culture filtrate (CCF) of Phytophthora infestans or purified lipopolysaccharides (LPS) from Pectobacterium atrosepticum. The kinetic of phenolics accumulation was followed and a set of typical phenolics was identified: chlorogenic acid, phenolamides and flavonols including rutin (quercetin-3-O-rutinoside) and nicotiflorin (kaempferol-3-O-rutinoside). Our results showed that CCF but not LPS induced differential accumulation of major phenolics among cultivars. Total phenolics were related with resistance to P. atrosepticum but not to P. infestans. However, nicotiflorin was inversely related with resistance to both pathogens. Rutin, but not nicotiflorin, inhibited pathogen growth in vitro at physiological concentrations. These data therefore suggest that (i) several phenolics are candidate markers for quantitative resistance in potato, (ii) some of these are pathogen specific although they are produced by a general defense pathway, (iii) resistance marker molecules do not necessarily have antimicrobial activity, and (iv) the final content of these target molecules-either constitutive or induced-is a better predictor of resistance than their inducibility by pathogen elicitors.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Resistance of essential fatty acid-deficient rats to endotoxin-induced increases in vascular permeability

    Energy Technology Data Exchange (ETDEWEB)

    Li, E.J.; Cook, J.A.; Spicer, K.M.; Wise, W.C.; Rokach, J.; Halushka, P.V. (Medical Univ. of South Carolina, Charleston (USA))

    1990-06-01

    Resistance to endotoxin in essential fatty acid-deficient (EFAD) rats is associated with reduced synthesis of certain arachidonic acid metabolites. It was hypothesized that EFAD rats would manifest decreased vascular permeability changes during endotoxemia as a consequence of reduced arachidonic acid metabolism. To test this hypothesis, changes in hematocrit (HCT) and mesenteric localization rate of technetium-labeled human serum albumin (99mTc-HSA) and red blood cells (99mTc-RBC) were assessed in EFAD and normal rats using gamma-camera imaging. Thirty minutes after Salmonella enteritidis endotoxin, EFAD rats exhibited less hemoconcentration as determined by % HCT than normal rats. Endotoxin caused a less severe change in permeability index in the splanchnic region in EFAD rats than in normal rats (1.2 +/- 0.6 x 10(-3)min-1 vs. 4.9 +/- 1.7 x 10(-3)min-1 respectively, P less than 0.05). In contrast to 99mTc-HSA, mesenteric localization of 99mTc-RBC was not changed by endotoxin in control or EFAD rats. Supplementation with ethyl-arachidonic acid did not enhance susceptibility of EFAD rats to endotoxin-induced splanchnic permeability to 99mTc-HSA. Leukotrienes have been implicated as mediators of increased vascular permeability in endotoxin shock. Since LTC3 formation has been reported to be increased in EFA deficiency, we hypothesized that LTC3 may be less potent than LTC4. Thus the effect of LTC3 on mean arterial pressure and permeability was compared to LTC4 in normal rats. LTC3-induced increases in peak mean arterial pressure were less than LTC4 at 10 micrograms/kg (39 +/- 5 mm Hg vs. 58 +/- 4 mm Hg respectively, P less than 0.05) and at 20 micrograms/kg (56 +/- 4 mm Hg vs. 75 +/- 2 mm Hg respectively, P less than 0.05). LY171883 (30 mg/kg), an LTD4/E4 receptor antagonist, attenuated the pressor effect of LTC4, LTD4, and LTC3.

  3. 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)

  4. High-fat diets rich in medium- versus long-chain fatty acids induce distinct patterns of tissue specific insulin resistance

    NARCIS (Netherlands)

    Vogel-van den Bosch, J. de; Berg, S.A.A. van den; Bijland, S.; Voshol, P.J.; Havekes, L.M.; Romijn, H.A.; Hoeks, J.; Beurden, D. van; Hesselink, M.K.C.; Schrauwen, P.; Dijk, K.W. van

    2011-01-01

    Excess dietary long-chain fatty acid (LCFA) intake results in ectopic lipid accumulation and insulin resistance. Since medium-chain fatty acids (MCFA) are preferentially oxidized over LCFA, we hypothesized that diets rich in MCFA result in a lower ectopic lipid accumulation and insulin resistance co

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Effects of phosphatidic acid supplementation on muscle thickness and strength in resistance-trained men.

    Science.gov (United States)

    Gonzalez, Adam M; Sell, Katie M; Ghigiarelli, Jamie J; Kelly, Christopher F; Shone, Edward W; Accetta, Matthew R; Baum, Jamie B; Mangine, Gerald T

    2017-04-01

    The purpose of this study was to investigate the effects of phosphatidic acid (PA) supplementation on muscle thickness and strength following an 8 week supervised resistance-training program. Fifteen resistance trained men (22.8 ± 3.5 years; 80.6 ± 8.7 kg; 178.1 ± 5.6 cm; 14.6% ± 8.8% body fat) were randomly assigned to a group that either consumed 750 mg of PA or a placebo (PL). Testing was carried out before (PRE) and after (POST) training/supplementation for muscle thickness and strength. Muscle thickness of the rectus femoris (RF), vastus lateralis (VL), biceps brachii (BB), and triceps brachii (TB) muscles were measured via ultrasonography, along with 1 repetition maximum (1RM) of squat, deadlift, and bench press. Analysis of covariance (ANCOVA), using PRE values as the covariate, did not reveal any group differences for measures of muscle thickness in the RF (PA: 3.6% ± 5.2%; PL: 3.2% ± 4.2%, p = 0.97), VL (PA: 23.4% ± 18.1%, PL: 12.5% ± 15.4%, p = 0.37), BB (PA: 3.7% ± 6.4%, PL: 9.6% ± 12.4%, p = 0.86), or TB (PA: 15.1% ± 17.9%, PL: 10.7% ± 19.3%, p = 0.79). Likewise, no group differences were observed in changes in squat (PA: 8.4% ± 4.1%, PL: 8.1% ± 4.2%, p = 0.79), deadlift (PA: 10.1% ± 10.1%, PL: 8.9% ± 9.5%, p = 0.66), or bench press (PA: 5.7% ± 5.5%, PL: 5.1% ± 3.0%, p = 0.76) exercises. Collectively, however, all participants experienced significant (p muscle thickness and strength. Results of this study suggest that PA supplementation, in combination with a 3 days·week(-1) resistance-training program for 8 weeks, did not have a differential effect compared with PL on changes in muscle thickness or 1RM strength.

  10. Polyacrylic acid-coated iron oxide nanoparticles for targeting drug resistance in mycobacteria.

    Science.gov (United States)

    Padwal, Priyanka; Bandyopadhyaya, Rajdip; Mehra, Sarika

    2014-12-23

    The emergence of drug resistance is a major problem faced in current tuberculosis (TB) therapy, representing a global health concern. Mycobacterium is naturally resistant to most drugs due to export of the latter outside bacterial cells by active efflux pumps, resulting in a low intracellular drug concentration. Thus, development of agents that can enhance the effectiveness of drugs used in TB treatment and bypass the efflux mechanism is crucial. In this study, we present a new nanoparticle-based strategy for enhancing the efficacy of existing drugs. To that end, we have developed poly(acrylic acid) (PAA)-coated iron oxide (magnetite) nanoparticles (PAA-MNPs) as efflux inhibitors and used it together with rifampicin (a first line anti-TB drug) on Mycobacterium smegmatis. PAA-MNPs of mean diameter 9 nm interact with bacterial cells via surface attachment and are then internalized by cells. Although PAA-MNP alone does not inhibit cell growth, treatment of cells with a combination of PAA-MNP and rifampicin exhibits a synergistic 4-fold-higher growth inhibition compared to rifampicin alone. This is because the combination of PAA-MNP and rifampicin results in up to a 3-fold-increased accumulation of rifampicin inside the cells. This enhanced intracellular drug concentration has been explained by real-time transport studies on a common efflux pump substrate, ethidium bromide (EtBr). It is seen that PAA-MNP increases the accumulation of EtBr significantly and also minimizes the EtBr efflux in direct proportion to the PAA-MNP concentration. Our results thus illustrate that the addition of PAA-MNP with rifampicin may bypass the innate drug resistance mechanism of M. smegmatis. This generic strategy is also found to be successful for other anti-TB drugs, such as isoniazid and fluoroquinolones (e.g., norfloxacin), only when stabilized, coated nanoparticles (such as PAA-MNP) are used, not PAA or MNP alone. We hence establish coated nanoparticles as a new class of efflux

  11. Influence of temperature and hydraulic retention on the production of volatile fatty acids during anaerobic fermentation of cow manure and maize silage.

    Science.gov (United States)

    Cavinato, Cristina; Da Ros, Cinzia; Pavan, Paolo; Bolzonella, David

    2017-01-01

    The aim of this study was to verify the efficiency of a separate hydrolysis step by testing different working temperatures (37-55°C) and hydraulic retention times (two, four and six days) and by evaluating readily biodegradable carbon production. The fermentation products included primarily acetic, propionic and butyric acids. These acids can be easily converted into biogas or can be recovered in a biorefinery approach, for example, to produce polyhydroxyalkanoates. The optimal condition was found by applying an organic loading rate of 17.9gTVSm(-3) with a four-day retention time at 37°C for an acidification yield of 183.2gCODVFAkgVSfed(-1).

  12. Relationship between acid tolerance and cell membrane in Bifidobacterium, revealed by comparative analysis of acid-resistant derivatives and their parental strains grown in medium with and without Tween 80.

    Science.gov (United States)

    Yang, Xu; Hang, Xiaomin; Zhang, Min; Liu, Xianglong; Yang, Hong

    2015-06-01

    The acid tolerance is particularly important for bifidobacteria to function as probiotics because they usually encounter acidic environments in food products and gastrointestinal tract passage. In this study, two acid-resistant derivatives Bifidobacterium longum JDY1017dpH and Bifidobacterium breve BB8dpH, which displayed a stable acid-resistant phenotype, were generated. The relationship between acid tolerance and cell membrane was investigated by comparing the two acid-resistant derivatives and their parental strains grown in medium with and without Tween 80. The fold increase in acid tolerance of the two acid-resistant derivatives relative to their parental strains was much higher when cells were grown in medium with Tween 80 (10(4) ~ 10(5)-fold) than without Tween 80 (181- and 245-fold). Moreover, when cells were grown in medium with Tween 80, the two acid-resistant derivatives exhibited more C18:1 and cycC19:0, higher mean fatty acid chain length, lower membrane fluidity, and higher expression of cfa gene encoding cyclopropane fatty acid synthase than their parental strains. No significant differences in cell membrane were observed between the two acid-resistant derivatives and their parental strains when cells were grown in medium without Tween 80. The present study revealed that, when cells were grown in medium with Tween 80, the significant fold increase in acid tolerance of the two acid-resistant derivatives was mainly ascribed to the pronounced changes in cell membrane compared with their parental strains. Results presented here could provide a basis for developing new strategies of cell membrane modification to enhance acid tolerance in bifidobacteria.

  13. Overexpression of ubiquitin and amino acid permease genes in association with antimony resistance in Leishmania tropica field isolates.

    Science.gov (United States)

    Kazemi-Rad, Elham; Mohebali, Mehdi; Khadem-Erfan, Mohammad Bagher; Hajjaran, Homa; Hadighi, Ramtin; Khamesipour, Ali; Rezaie, Sassan; Saffari, Mojtaba; Raoofian, Reza; Heidari, Mansour

    2013-08-01

    The mainstay therapy against leishmaniasis is still pentavalent antimonial drugs; however, the rate of antimony resistance is increasing in endemic regions such as Iran. Understanding the molecular basis of resistance to antimonials could be helpful to improve treatment strategies. This study aimed to recognize genes involved in antimony resistance of Leishmania tropica field isolates. Sensitive and resistant L. tropica parasites were isolated from anthroponotic cutaneous leishmaniasis patients and drug susceptibility of parasites to meglumine antimoniate (Glucantime®) was confirmed using in vitro assay. Then, complementary DNA-amplified fragment length polymorphism (cDNA-AFLP) and real-time reverse transcriptase-PCR (RT-PCR) approaches were utilized on mRNAs from resistant and sensitive L. tropica isolates. We identified 2 known genes, ubiquitin implicated in protein degradation and amino acid permease (AAP3) involved in arginine uptake. Also, we identified 1 gene encoding hypothetical protein. Real-time RT-PCR revealed a significant upregulation of ubiquitin (2.54-fold), and AAP3 (2.86-fold) (P<0.05) in a resistant isolate compared to a sensitive one. Our results suggest that overexpression of ubiquitin and AAP3 could potentially implicated in natural antimony resistance.

  14. 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.

  15. Foaming phenomenon in bench-scale anaerobic digesters.

    Science.gov (United States)

    Siebels, Amanda M; Long, Sharon C

    2013-04-01

    The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Sulphuric Acid Resistant of Self Compacted Geopolymer Concrete Containing Slag and Ceramic Waste

    Directory of Open Access Journals (Sweden)

    Shafiq I.

    2017-01-01

    Full Text Available Malaysia is a one of the developing countries where the constructions of infrastructure is still ongoing, resulting in a high demand for concrete. In order to gain sustainability factors in the innovations for producing concrete, geopolymer concrete containing granulated blast-furnace slag and ceramics was selected as a cement replacement in concrete for this study. Since Malaysia had many ceramic productions and uses, the increment of the ceramic waste will also be high. Thus, a new idea to reuse this waste in construction materials have been tested by doing research on this waste. Furthermore, a previous research stated that Ordinary Portland Cement concrete has a lower durability compared to the geopolymer concrete. Geopolymer binders have been reported as being acid resistant and thus are a promising and alternative binder for sewer pipe manufacture. Lack of study regarding the durability of the geopolymer self-compacting concrete was also one of the problems. The waste will be undergoing a few processes in the laboratory in order to get it in the best form before undergoing the next process as a binder in geopolymer concrete. This research is very significant in order to apply the concept of sustainability in the construction field. In addition, the impact of this geopolymer binder is that it emits up to nine times less CO2 than Portland Cement.

  4. Research on bio-production of short-chain fatty acids from excess sludge during anaerobic digestion%污水厂污泥厌氧消化产短链脂肪酸研究进展

    Institute of Scientific and Technical Information of China (English)

    高鹏; 张栋; 贾舒婷; 董滨; 戴晓虎

    2013-01-01

    Bio-production of short-chain fatty acids (SCFAs) under anaerobic digestion can be an important way to recycle excess sludge. SCFAs could be used to generate methane,to remove nitrogen and phosphorous from wastewater as carbon sources added in wastewater treatment plants(WWTP), and to make valuable products,such as PHA etc. This paper reviewed the mechanism of acidogenesis process during sludge anaerobic digestion,focusing on the most important impact factors such as the sludge characteristics,fermentative temperature,pH value,carbon to nitrogen ratio(C/N),hydraulic retention time(HRT) and the solids retention time(SRT). These impact factors could affect the SCFAs production by changing the substrates characteristics,microbial activities and the reaction time between substrates and microbes. Temperature and pH value obtained more attention in recent research and it was reported that higher fermentation temperatures and alkaline conditions were more suitable for the acidogenesis process. It is important to investigate the suitable fermentative conditions for excess sludge to maximize SCFAs production under anaerobic digestion. The relationship among the impact factors and adjusting the impact factors to control of SCFs production can become a promising research direction in future.%污泥厌氧消化产短链脂肪酸是实现污泥资源化的重要途径,短链脂肪酸不仅是产甲烷的底物、污水脱氮除磷的碳源,而且可以作为原料产生一系列高附加值的产品。本文介绍了污泥厌氧消化产有机酸的机理,重点阐述了污泥性质、温度、pH 值、碳氮比(C/N)、水力停留时间(HRT)和固体停留时间(SRT)等影响污泥厌氧消化产酸的主要因素及研究进展,指出这些因素通过改变底物性质、微生物活性及二者接触反应时间等对产酸过程产生影响,其中温度和pH值是研究热点,目前大多数研究者认为高温和碱性条件更有利于污泥产

  5. 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.

  6. New amino acid changes in drug resistance sites and HBsAg in hepatitis B virus genotype H.

    Science.gov (United States)

    Fernández-Galindo, D A; Sánchez-Ávila, F; Bobadilla-Morales, L; Gómez-Quiróz, P; Bueno-Topete, M; Armendáriz-Borunda, J; Sánchez-Orozco, L V

    2015-06-01

    Long-term treatment with retrotranscriptase (RT) inhibitors eventually leads to the development of drug resistance. Drug-related mutations occur naturally and these can be found in hepatitis B virus (HBV) carriers who have never received antiviral therapy. HBsAg are overlapped with RT domain, thus nucleot(s)ide analogues (NAs) resistance mutations and naturally-occurring mutations can cause amino acid changes in the HBsAg. Twenty-two patients with chronic hepatitis B were enrolled; three of them were previously treated with NAs and 19 were NAs-naïve treated. HBV reverse transcriptase region was sequenced; genotyping and analysis of missense mutations were performed in both RT domain and HBsAg. There was predominance of genotype H. Drug mutations were present in 18.2% of patients. Classical lamivudine resistance mutations (rtM204V/rtL180M) were present in one naïve-treatment patient infected with genotype G. New amino acid changes were identified in drug resistance sites in HBV strains from patients infected with genotype H; rtQ215E was present in two naïve-NAs treatment patients and rtI169M was identified in a patient previously treated with lamivudine. Mutations at sites rt169, rt204, and rt215 resulted in the Y161C, I195M, and C206W mutations at HBsAg. Also, new amino acid changes were identified in B-cell and T-cell epitopes and were more frequent in HBsAg compared to RT domain. In conclusion, new amino acid changes at antiviral resistance sites, B-cell and T-cell epitopes in HBV genotype H were identified in Mexican patients.

  7. 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.

  8. 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

  9. The Epoxyeicosatrienoic Acid Pathway Enhances Hepatic Insulin Signaling and is Repressed in Insulin-Resistant Mouse Liver*

    Science.gov (United States)

    Schäfer, Alexander; Neschen, Susanne; Kahle, Melanie; Sarioglu, Hakan; Gaisbauer, Tobias; Imhof, Axel; Adamski, Jerzy; Hauck, Stefanie M.; Ueffing, Marius

    2015-01-01

    Although it is widely accepted that ectopic lipid accumulation in the liver is associated with hepatic insulin resistance, the underlying molecular mechanisms have not been well characterized. Here we employed time resolved quantitative proteomic profiling of mice fed a high fat diet to determine which pathways were affected during the transition of the liver to an insulin-resistant state. We identified several metabolic pathways underlying altered protein expression. In order to test the functional impact of a critical subset of these alterations, we focused on the epoxyeicosatrienoic acid (EET) eicosanoid pathway, whose deregulation coincided with the onset of hepatic insulin resistance. These results suggested that EETs may be positive modulators of hepatic insulin signaling. Analyzing EET activity in primary hepatocytes, we found that EETs enhance insulin signaling on the level of Akt. In contrast, EETs did not influence insulin receptor or insulin receptor substrate-1 phosphorylation. This effect was mediated through the eicosanoids, as overexpression of the deregulated enzymes in absence of arachidonic acid had no impact on insulin signaling. The stimulation of insulin signaling by EETs and depression of the pathway in insulin resistant liver suggest a likely role in hepatic insulin resistance. Our findings support therapeutic potential for inhibiting EET degradation. PMID:26070664

  10. Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli.

    Science.gov (United States)

    Dwivedi, Gaurav Raj; Tiwari, Nimisha; Singh, Aastha; Kumar, Akhil; Roy, Sudeep; Negi, Arvind Singh; Pal, Anirban; Chanda, Debabrata; Sharma, Ashok; Darokar, Mahendra P

    2016-03-01

    The purpose of the present study was to study the synergy potential of gallic acid-based derivatives in combination with conventional antibiotics using multidrug resistant cultures of Escherichia coli. Gallic acid-based derivatives significantly reduced the MIC of tetracycline against multidrug resistant clinical isolate of E. coli. The best representative, 3-(3',4,'5'-trimethoxyphenyl)-4,5,6-trimethoxyindanone-1, an indanone derivative of gallic acid, was observed to inhibit ethidium bromide efflux and ATPase which was also supported by in silico docking. This derivative extended the post-antibiotic effect and decreased the mutation prevention concentration of tetracycline. This derivative in combination with TET was able to reduce the concentration of TNFα up to 18-fold in Swiss albino mice. This derivative was nontoxic and well tolerated up to 300 mg/kg dose in subacute oral toxicity study in mice. This is the first report of gallic acid-based indanone derivative as drug resistance reversal agent acting through ATP-dependent efflux pump inhibition.

  11. Growth temperature alters Salmonella Enteritidis heat/acid resistance, membrane lipid composition and stress/virulence related gene expression.

    Science.gov (United States)

    Yang, Yishan; Khoo, Wei Jie; Zheng, Qianwang; Chung, Hyun-Jung; Yuk, Hyun-Gyun

    2014-02-17

    The influence of growth temperature (10, 25, 37, and 42 °C) on the survival of Salmonella Enteritidis in simulated gastric fluid (SGF; pH=2.0) and during heat treatment (54, 56, 58, and 60 °C), on the membrane fatty acid composition, as well as on stress-/virulence-related gene expression was studied. Cells incubated at temperatures lower or higher than 37 °C did not increase their acid resistance, with the maximum D-value of 3.07 min in cells grown at 37 °C; while those incubated at higher temperature increased their heat resistance, with the maximum D60 °C-values of 1.4 min in cells grown at 42 °C. A decrease in the ratio of unsaturated to saturated fatty acids was observed as the growth temperature increased. Compared to the control cells grown at 37 °C, the expression of rpoS was 16.5- and 14.4-fold higher in cells cultivated at 10 and 25 °C, respectively; while the expression of rpoH was 2.9-fold higher in those cultivated at 42 °C. The increased expression of stress response gene rpoH and the decreased ratio of unsaturated to saturated fatty acids correlated with the greater heat resistance of bacteria grown at 42 °C; while the decreased expression of stress response gene rpoS at 42 °C might contribute to the decrease in acid resistance. Virulence related genes-spvR, hilA, avrA-were induced in cells cultivated at 42 °C, except sefA which was induced in the control cells. This study indicates that environmental temperature may affect the virulence potential of S. Enteritidis, thus temperature should be well controlled during food storage.

  12. 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.

  13. Modeling of two-phase anaerobic process treating traditional Chinese medicine wastewater with the IWA Anaerobic Digestion Model No. 1.

    Science.gov (United States)

    Chen, Zhaobo; Hu, Dongxue; Zhang, Zhenpeng; Ren, Nanqi; Zhu, Haibo

    2009-10-01

    The aim of the study was to implement a mathematical model to simulate two-phase anaerobic digestion (TPAD) process which consisted of an anaerobic continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket (UASB) reactor in series treating traditional Chinese medicine (TCM) wastewater. A model was built on the basis of Anaerobic Digestion Model No. 1 (ADM1) while considering complete mixing model for the CSTR, and axial direction discrete model and mixed series connection model for the UASB. The mathematical model was implemented with the simulation software package MATLABTM/Simulinks. System performance, in terms of COD removal, volatile fatty acids (VFA) accumulation and pH fluctuation, was simulated and compared with the measured values. The simulation results indicated that the model built was able to well predict the COD removal rate (-4.8-5.0%) and pH variation (-2.9-1.4%) of the UASB reactor, while failed to simulate the CSTR performance. Comparing to the measured results, the simulated acetic acid concentration of the CSTR effluent was underpredicted with a deviation ratios of 13.8-23.2%, resulting in an underprediction of total VFA and COD concentrations despite good estimation of propionic acid, butyric acid and valeric acid. It is presumed that ethanol present in the raw wastewater was converted into acetic acid during the acidification process, which was not considered by the model. Additionally, due to the underprediction of acetic acid the pH of CSTR effluent was overestimated.

  14. 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.

  15. 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.

  16. 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 Ca2+ 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

  17. 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.

  18. 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

    2015-08-03

    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

  19. Targeted metabolomic analysis reveals the association between the postprandial change in palmitic acid, branched-chain amino acids and insulin resistance in young obese subjects.

    Science.gov (United States)

    Liu, Liyan; Feng, Rennan; Guo, Fuchuan; Li, Ying; Jiao, Jundong; Sun, Changhao

    2015-04-01

    Obesity is the result of a positive energy balance and often leads to difficulties in maintaining normal postprandial metabolism. The changes in postprandial metabolites after an oral glucose tolerance test (OGTT) in young obese Chinese men are unclear. In this work, the aim is to investigate the complex metabolic alterations in obesity provoked by an OGTT using targeted metabolomics. We used gas chromatography-mass spectrometry and ultra high performance liquid chromatography-triple quadrupole mass spectrometry to analyze serum fatty acids, amino acids and biogenic amines profiles from 15 control and 15 obese subjects at 0, 30, 60, 90 and 120 min during an OGTT. Metabolite profiles from 30 obese subjects as independent samples were detected in order to validate the change of metabolites. There were the decreased levels of fatty acid, amino acids and biogenic amines after OGTT in obesity. At 120 min, percent change of 20 metabolites in obesity has statistical significance when comparing with the controls. The obese parameters was positively associated with changes in arginine and histidine (Ppalmitic acid (PA), branched-chain amino acids (BCAAs) and phenylalanine between 1 and 120 min were positively associated with fasting insulin and HOMA-IR (all P<0.05) in the obese group. The postprandial metabolite of PA and BCAAs may play important role in the development and onset of insulin resistance in obesity. Our findings offer new insights in the complex physiological regulation of the metabolism during an OGTT in obesity.

  20. 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.

  1. Role of the multidrug resistance regulator MarA in global regulation of the hdeAB acid resistance operon in Escherichia coli.

    Science.gov (United States)

    Ruiz, Cristian; McMurry, Laura M; Levy, Stuart B

    2008-02-01

    MarA, a transcriptional regulator in Escherichia coli, affects functions such as multiple-antibiotic resistance (Mar) and virulence. Usually an activator, MarA is a repressor of hdeAB and other acid resistance genes. We found that, in wild-type cells grown in LB medium at pH 7.0 or pH 5.5, repression of hdeAB by MarA occurred only in stationary phase and was reduced in the absence of H-NS and GadE, the main regulators of hdeAB. Moreover, repression of hdeAB by MarA was greater in the absence of GadX or Lrp in exponential phase at pH 7.0 and in the absence of GadW or RpoS in stationary phase at pH 5.5. In turn, MarA enhanced repression of hdeAB by H-NS and hindered activation by GadE in stationary phase and also reduced the activity of GadX, GadW, RpoS, and Lrp on hdeAB under some conditions. As a result of its direct and indirect effects, overexpression of MarA prevented most of the induction of hdeAB expression as cells entered stationary phase and made the cells sevenfold more sensitive to acid challenge at pH 2.5. These findings show that repression of hdeAB by MarA depends on pH, growth phase, and other regulators of hdeAB and is associated with reduced resistance to acid conditions.

  2. Anaerobic Nitrogen Fixers on Mars

    Science.gov (United States)

    Lewis, B. G.

    2000-07-01

    The conversion of atmospheric nitrogen gas to the protein of living systems is an amazing process of nature. The first step in the process is biological nitrogen fixation, the transformation of N2 to NH3. The phenomenon is crucial for feeding the billions of our species on Earth. On Mars, the same process may allow us to discover how life can adapt to a hostile environment, and render it habitable. Hostile environments also exist on Earth. For example, nothing grows in coal refuse piles due to the oxidation of pyrite and marcasite to sulfuric acid. Yet, when the acidity is neutralized, alfalfa and soybean plants develop root nodules typical of symbiotic nitrogen fixation with Rhizobium species possibly living in the pyritic material. When split open, these nodules exhibited the pinkish color of leghemoglobin, a protein in the nodule protecting the active nitrogen-fixing enzyme nitrogenase against the toxic effects of oxygen. Although we have not yet obtained direct evidence of nitrogenase activity in these nodules (reduction of acetylene to ethylene, for example), these findings suggested the possibility that nitrogen fixation was taking place in this hostile, non-soil material. This immediately raises the possibility that freeliving anaerobic bacteria which fix atmospheric nitrogen on Earth, could do the same on Mars.

  3. 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

    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....... 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...... of fermentation for full-scale application was roughly estimated based on the experiments performed in semi-continuous reactors. The results revealed that even though the VFA production of primary sludge was higher compared to activated sludge, substantial amounts of VFA could be produced by fermentation...

  4. 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.

  5. Effects of β-Hydroxy-β-methylbutyrate Free Acid Ingestion and Resistance Exercise on the Acute Endocrine Response

    Directory of Open Access Journals (Sweden)

    Jeremy R. Townsend

    2015-01-01

    Full Text Available Objective. To examine the endocrine response to a bout of heavy resistance exercise following acute β-hydroxy-β-methylbutyrate free acid (HMB-FA ingestion. Design. Twenty resistance trained men were randomized and consumed either 1 g of HMB-FA (BetaTor or placebo (PL 30 min prior to performing an acute heavy resistance exercise protocol. Blood was obtained before (PRE, immediately after (IP, and 30 min after exercise (30P. Circulating concentrations of testosterone, growth hormone (GH, insulin-like growth factor (IGF-1, and insulin were assayed. Data were analyzed with a repeated measures ANOVA and area under the curve (AUC was analyzed by the trapezoidal rule. Results. The resistance exercise protocol resulted in significant elevations from PRE in testosterone P<0.01, GH P<0.01, and insulin P=0.05 at IP, with GH P<0.01 and insulin P<0.01 remaining elevated at 30P. A significant interaction was noted between groups in the plasma GH response at IP, which was significantly higher following HMB-FA compared to PL P<0.01. AUC analysis revealed an elevated GH and IGF-1 response in the HMB-FA group compared to PL. Conclusion. HMB-FA prior to resistance exercise augments the GH response to high volume resistance exercise compared to PL. These findings provide further support for the potential anabolic benefits associated with HMB supplementation.

  6. [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.

  7. Comparison of endogenous metabolism during long-term anaerobic starvation of nitrite/nitrate cultivated denitrifying phosphorus removal sludges.

    Science.gov (United States)

    Wang, Yayi; Zhou, Shuai; Wang, Hong; Ye, Liu; Qin, Jian; Lin, Ximao

    2015-01-01

    Denitrifying phosphorus removal (DPR) by denitrifying phosphorus-accumulating organisms (DPAOs) is a promising approach for reducing energy and carbon usage. However, influent fluctuations or interruptions frequently expose the DPAOs biomass to starvation conditions, reducing biomass activity and amount, and ultimately degrading the performance of DPR. Therefore, a better understanding of the endogenous metabolism and recovery ability of DPAOs is urgently required. In the present study, anaerobic starvation (12 days) and recovery were investigated in nitrite- and nitrate-cultivated DPAOs at 20 ± 1 °C. The cell decay rates in nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were 0.008 day⁻¹ and 0.007 day⁻¹, respectively, being 64% and 68% lower than those of nitrate-DPAOs sludges. Nitrite-DPAOs sludges also recovered more rapidly than nitrate-DPAOs sludge after 12 days of starvation. The maintenance energy of nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were approximately 31% and 34% lower, respectively, than those of nitrate-DPAOs sludges. Glycogen and polyphosphate (poly-P) sequentially served as the main maintenance energy sources in both nitrite-and nitrate-DPAOs sludges. However, the transformation pathway of the intracellular polymers during starvation differed between them. Nitrate-DPAOs sludge used extracellular polymeric substances (EPS) (mainly polysaccharides) as an additional maintenance energy source during the first 3 days of starvation. During this phase, EPS appeared to contribute to 19-27% of the ATP production in nitrate-DPAOs, but considerably less to the cell maintenance of nitrite-DPAOs. The high resistance of nitrite-DPAOs to starvation might be attributable to frequent short-term starvation and exposure to toxic substances such as nitrite/free nitrous acids in the parent nitrite-fed reactor. The strong resistance of nitrite-DPAOs sludge to anaerobic starvation may be exploited in P removal

  8. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;

    2001-01-01

    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...... 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...

  9. 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

  10. 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...

  11. Anaerobic mineralization of toluene by enriched sediments with quinones and humus as terminal electron acceptors

    NARCIS (Netherlands)

    Cervantes, F.J.; Dijksma, W.; Duong-Dac, T.; Ivanova, A.; Lettinga, G.; Field, J.A.

    2001-01-01

    The anaerobic microbial oxidation of toluene to CO2 coupled to humus respiration was demonstrated by use of enriched anaerobic sediments from the Amsterdam petroleum harbor (APH) and the Rhine River. Both highly purified soil humic acids (HPSHA) and the humic quinone moiety model compound anthraquin

  12. 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.

  13. 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.

  14. Chemical mutagenesis of Gluconobacter frateurii to construct methanol-resistant mutants showing glyceric acid production from methanol-containing glycerol.

    Science.gov (United States)

    Sato, Shun; Kitamoto, Dai; Habe, Hiroshi

    2014-02-01

    To produce glyceric acid (GA) from methanol-containing glycerol, resistance to methanol of Gluconobacter frateurii NBRC103465 was improved by chemical mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine. The obtained mutant Gf398 produced 6.3 g/L GA in 5% (v/v) methanol-containing 17% (w/v) glycerol medium, in which the wild-type strain neither grew nor produced GA.

  15. 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...

  16. Induction of YdeO, a regulator for acid resistance genes, by ultraviolet irradiation in Escherichia coli.

    Science.gov (United States)

    Yamanaka, Yuki; Ishihama, Akira; Yamamoto, Kaneyoshi

    2012-01-01

    YdeO, an AraC-type transcription factor, is an important regulator in the induction of acid-resistance genes in Escherichia coli. In this study, we found that ydeO expression was induced 20 min after exposure to UV irradiation. This required the evgA and gadE genes in vivo. YdeO, induced by UV, controls the expression of a total of 21 genes. This accompanies SOS response in E. coli.

  17. 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...... 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...... 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...

  18. Differential control of cholesterol and fatty acid biosynthesis in sensitive and multidrug-resistant LoVo tumor cells.

    Science.gov (United States)

    Santini, Maria Teresa; Napolitano, Mariarosaria; Ferrante, Antonella; Rainaldi, Gabriella; Arancia, Giuseppe; Bravo, Elena

    2003-01-01

    Multidrug resistance (MDR) describes the decrease in sensitivity of tumor cells to a wide variety of cytotoxic compounds. Although a central role has been ascribed to the P-glycoprotein (Pgp) pump in MDR, lipids also appear to be extremely important. However, their precise role in MDR is not yet fully understood. It was the aim of the present paper to gain a deeper understanding of intracellular lipid equilibrium in both sensitive and MDR tumor cells. In particular, intracellular cholesterol biosynthesis and cholesterol esterification were examined in LoVo-sensitive and Pgp-overexpressing resistant cells. The data presented seem to suggest that the higher synthesis of cholesteryl ester and triglyceride observed in resistant with respect to wild-type cells is due to a greater production of fatty acids in these cells. The results are discussed in view of the possible roles of sterol regulatory element-binding proteins and Pgp in these phenomena.

  19. A novel aspartic acid protease gene from pineapple fruit (Ananas comosus): cloning, characterization and relation to postharvest chilling stress resistance.

    Science.gov (United States)

    Raimbault, Astrid-Kim; Zuily-Fodil, Yasmine; Soler, Alain; Cruz de Carvalho, Maria H

    2013-11-15

    A full-length cDNA encoding a putative aspartic acid protease (AcAP1) was isolated for the first time from the flesh of pineapple (Ananas comosus) fruit. The deduced sequence of AcAP1 showed all the common features of a typical plant aspartic protease phytepsin precursor. Analysis of AcAP1 gene expression under postharvest chilling treatment in two pineapple varieties differing in their resistance to blackheart development revealed opposite trends. The resistant variety showed an up-regulation of AcAP1 precursor gene expression whereas the susceptible showed a down-regulation in response to postharvest chilling treatment. The same trend was observed regarding specific AP enzyme activity in both varieties. Taken together our results support the involvement of AcAP1 in postharvest chilling stress resistance in pineapple fruits.

  20. 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.

  1. 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

  2. A novel small acid soluble protein variant is important for spore resistance of most Clostridium perfringens food poisoning isolates.

    Directory of Open Access Journals (Sweden)

    Jihong Li

    2008-05-01

    Full Text Available Clostridium perfringens is a major cause of food poisoning (FP in developed countries. C. perfringens isolates usually induce the gastrointestinal symptoms of this FP by producing an enterotoxin that is encoded by a chromosomal (cpe gene. Those typical FP strains also produce spores that are extremely resistant to food preservation approaches such as heating and chemical preservatives. This resistance favors their survival and subsequent germination in improperly cooked, prepared, or stored foods. The current study identified a novel alpha/beta-type small acid soluble protein, now named Ssp4, and showed that sporulating cultures of FP isolates producing resistant spores consistently express a variant Ssp4 with an Asp substitution at residue 36. In contrast, Gly was detected at Ssp4 residue 36 in C. perfringens strains producing sensitive spores. Studies with isogenic mutants and complementing strains demonstrated the importance of the Asp 36 Ssp4 variant for the exceptional heat and sodium nitrite resistance of spores made by most FP strains carrying a chromosomal cpe gene. Electrophoretic mobility shift assays and DNA binding studies showed that Ssp4 variants with an Asp at residue 36 bind more efficiently and tightly to DNA than do Ssp4 variants with Gly at residue 36. Besides suggesting one possible mechanistic explanation for the highly resistant spore phenotype of most FP strains carrying a chromosomal cpe gene, these findings may facilitate eventual development of targeted strategies to increase killing of the resistant spores in foods. They also provide the first indication that SASP variants can be important contributors to intra-species (and perhaps inter-species variations in bacterial spore resistance phenotypes. Finally, Ssp4 may contribute to spore resistance properties throughout the genus Clostridium since ssp4 genes also exist in the genomes of other clostridial species.

  3. 高产琥珀酸重组大肠杆菌的构建及厌氧发酵%Construction and anaerobic fermentation of genetically engineered Escherichia coli for the production of succinic acid

    Institute of Scientific and Technical Information of China (English)

    赵锦芳; 华渤文; 王永泽; 赵筱; 王金华

    2013-01-01

    In this study, metabolic pathway engineering using Red recombinase system was performed on Escherichia coli W, a wild type strain, for the production of succinic acid. In order to eliminate the by-product formation of E. coli fermentation, five genes leading for production of lactate (ldhA) , formate. (pflB) ethanol (adhE) , and acetate (poxB and ackA) were deleted from the chromosome. The resulting mutant was then further selected through a-daptive (metabolic) evolution for improved anaerobic growth. The evolved strain WS100 could produce succinate as the major fermentation product. In a 15 L fermentation under anaerobic condition using mineral salt medium, WS100 produced 70. 13 g/L succinate from 100 g/L glucose in 72 h, with a volumetric productivity of 0. 98 g/( L · h) and a yield of 76% based on sugar metabolism. Although small amount of acetate and lactate were still produced as the minor by - products, there was no detectable production of formate and ethanol. This result demonstrated the great potential of the engineered E. coli WS100 for fermentative production of succinic acid at large scale.%以野生型大肠杆菌Escherichia coli W为出发菌株,利用Red同源重组系统分别敲除了乳酸脱氢酶基因(ldhA)、乙醇脱氢酶基因(adhE)、丙酮酸甲酸裂解酶基因(pflB)、丙酮酸氧化酶基因(poxB)和乙酸激酶基因(ackA),再通过无氧生长进化筛选过程,构建得到在厌氧条件下能有效生长,并以琥珀酸为主要发酵产物的重组大肠杆菌WS100(△ldhA,△adhE,△pflB,△poxB,△ackA).利用15 L发酵罐进行厌氧发酵测定显示,经72 h发酵,菌体密度OD600最大值可提高至6.48,琥珀酸产量达到70.13 g/L,琥珀酸的生产强度为0.98 g/(L· h),葡萄糖-琥珀酸转化率为76%.发酵液中副产物含量低,乙酸含量为5.34 g/L,乳酸产量仅为0.15 g/L,未检测到甲酸和乙醇生成.结果表明,厌氧条件下,该工程菌可有效利用低营养成分的无机盐培养基,在

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Benzoylsalicylic acid isolated from seed coats of Givotia rottleriformis induces systemic acquired resistance in tobacco and Arabidopsis.

    Science.gov (United States)

    Kamatham, Samuel; Neela, Kishore Babu; Pasupulati, Anil Kumar; Pallu, Reddanna; Singh, Surya Satyanarayana; Gudipalli, Padmaja

    2016-06-01

    Systemic acquired resistance (SAR), a whole plant defense response to a broad spectrum of pathogens, is characterized by a coordinated expression of a large number of defense genes. Plants synthesize a variety of secondary metabolites to protect themselves from the invading microbial pathogens. Several studies have shown that salicylic acid (SA) is a key endogenous component of local and systemic disease resistance in plants. Although SA is a critical signal for SAR, accumulation of endogenous SA levels alone is insufficient to establish SAR. Here, we have identified a new acyl derivative of SA, the benzoylsalicylic acid (BzSA) also known as 2-(benzoyloxy) benzoic acid from the seed coats of Givotia rottleriformis and investigated its role in inducing SAR in tobacco and Arabidopsis. Interestingly, exogenous BzSA treatment induced the expression of NPR1 (Non-expressor of pathogenesis-related gene-1) and pathogenesis related (PR) genes. BzSA enhanced the expression of hypersensitivity related (HSR), mitogen activated protein kinase (MAPK) and WRKY genes in tobacco. Moreover, Arabidopsis NahG plants that were treated with BzSA showed enhanced resistance to tobacco mosaic virus (TMV) as evidenced by reduced leaf necrosis and TMV-coat protein levels in systemic leaves. We, therefore, conclude that BzSA, hitherto unknown natural plant product, is a new SAR inducer in plants.

  9. 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)

  10. Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise.

    Science.gov (United States)

    Moberg, Marcus; Apró, William; Ekblom, Björn; van Hall, Gerrit; Holmberg, Hans-Christer; Blomstrand, Eva

    2016-06-01

    Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mammalian target of rapamycin complex 1 (mTORC1) signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA, and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA, or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise, and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6 kinase 1 (S6K1) was greater than at rest in all four trials (PlaceboBCAABCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P BCAA.

  11. 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.

  12. 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 sol