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1

Genera and species in acetic acid bacteria.  

PubMed

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically. PMID:18199517

Yamada, Yuzo; Yukphan, Pattaraporn

2008-06-30

2

Correlation between acetic acid resistance and characteristics of PQQ-dependent ADH in acetic acid bacteria.  

PubMed

In this study, we compared the growth properties and molecular characteristics of pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) among highly acetic acid-resistant strains of acetic acid bacteria. Gluconacetobacter europaeus exhibited the highest resistance to acetic acid (10%), whereas Gluconacetobacter intermedius and Acetobacter pasteurianus resisted up to 6% of acetic acid. In media with different concentrations of acetic acid, the maximal acetic acid production rate of Ga. europaeus slowly increased, but specific growth rates decreased concomitant with increased concentration of acetic acid in medium. The lag phase of A. pasteurianus was twice and four times longer in comparison to the lag phases of Ga. europaeus and Ga. intermedius, respectively. PQQ-dependent ADH activity was twice as high in Ga. europaeus and Ga. intermedius as in A. pasteurinus. The purified enzymes showed almost the same specific activity to each other, but in the presence of acetic acid, the enzyme activity decreased faster in A. pasteurianus and Ga. intermedius than in Ga. europaeus. These results suggest that high ADH activity in the Ga. europaeus cells and high acetic acid stability of the purified enzyme represent two of the unique features that enable this species to grow and stay metabolically active at extremely high concentrations of acetic acid. PMID:16133326

Trcek, Janja; Toyama, Hirohide; Czuba, Jerzy; Misiewicz, Anna; Matsushita, Kazunobu

2006-04-01

3

Characterization of acetic acid bacteria in "traditional balsamic vinegar".  

PubMed

This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with concentrated cooked must. On the contrary, ethanol concentration of the cooked and fermented must is less significant for acetic acid bacteria growth. A tentative identification of the isolated strains was done by 16S-23S-5S rDNA PCR/RFLP technique and the isolated strains were clustered: 32 strains belong to Gluconacetobacter xylinus group, two strains to Acetobacter pasteurianus group and one to Acetobacter aceti. PMID:16214251

Gullo, Maria; Caggia, Cinzia; De Vero, Luciana; Giudici, Paolo

2006-02-01

4

Recent advances in nitrogen-fixing acetic acid bacteria.  

PubMed

Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects, as well as their association with different plants and contribution through BNF are described as an overview. PMID:18177965

Pedraza, Raúl O

2008-06-30

5

Acetic acid bacteria isolated from grapes of South Australian vineyards.  

PubMed

Acetic acid bacteria (AAB) diversity from healthy, mould-infected and rot-affected grapes collected from three vineyards of Adelaide Hills (South Australia) was analyzed by molecular typing and identification methods. Nine different AAB species were identified from the 624 isolates recovered: Four species from Gluconobacter genus, two from Asaia and one from Acetobacter were identified by the analysis of 16S rRNA gene and 16S-23S rRNA gene internal transcribed spacer. However, the identification of other isolates that were assigned as Asaia sp. and Ameyamaea chiangmaiensis required more analysis for a correct species classification. The species of Gluconobacter cerinus was the main one identified; while one genotype of Asaia siamensis presented the highest number of isolates. The number of colonies recovered and genotypes identified was strongly affected by the infection status of the grapes; the rot-affected with the highest number. However, the species diversity was similar in all the cases. High AAB diversity was detected with a specific genotype distribution for each vineyard. PMID:24681711

Mateo, E; Torija, M J; Mas, A; Bartowsky, E J

2014-05-16

6

Acetic Acid Bacteria, Newly Emerging Symbionts of Insects?  

PubMed Central

Recent research in microbe-insect symbiosis has shown that acetic acid bacteria (AAB) establish symbiotic relationships with several insects of the orders Diptera, Hymenoptera, Hemiptera, and Homoptera, all relying on sugar-based diets, such as nectars, fruit sugars, or phloem sap. To date, the fruit flies Drosophila melanogaster and Bactrocera oleae, mosquitoes of the genera Anopheles and Aedes, the honey bee Apis mellifera, the leafhopper Scaphoideus titanus, and the mealybug Saccharicoccus sacchari have been found to be associated with the bacterial genera Acetobacter, Gluconacetobacter, Gluconobacter, Asaia, and Saccharibacter and the novel genus Commensalibacter. AAB establish symbiotic associations with the insect midgut, a niche characterized by the availability of diet-derived carbohydrates and oxygen and by an acidic pH, selective factors that support AAB growth. AAB have been shown to actively colonize different insect tissues and organs, such as the epithelia of male and female reproductive organs, the Malpighian tubules, and the salivary glands. This complex topology of the symbiosis indicates that AAB possess the keys for passing through body barriers, allowing them to migrate to different organs of the host. Recently, AAB involvement in the regulation of innate immune system homeostasis of Drosophila has been shown, indicating a functional role in host survival. All of these lines of evidence indicate that AAB can play different roles in insect biology, not being restricted to the feeding habit of the host. The close association of AAB and their insect hosts has been confirmed by the demonstration of multiple modes of transmission between individuals and to their progeny that include vertical and horizontal transmission routes, comprising a venereal one. Taken together, the data indicate that AAB represent novel secondary symbionts of insects.

Crotti, Elena; Rizzi, Aurora; Chouaia, Bessem; Ricci, Irene; Favia, Guido; Alma, Alberto; Sacchi, Luciano; Bourtzis, Kostas; Mandrioli, Mauro; Cherif, Ameur; Bandi, Claudio; Daffonchio, Daniele

2010-01-01

7

Acetic acid bacteria in traditional balsamic vinegar: phenotypic traits relevant for starter cultures selection.  

PubMed

This review focuses on acetic acid bacteria in traditional balsamic vinegar process. Although several studies are available on acetic acid bacteria ecology, metabolism and nutritional requirements, their activity as well as their technological traits in homemade vinegars as traditional balsamic vinegar is not well known. The basic technology to oxidise cooked grape must to produce traditional balsamic vinegar is performed by the so called "seed-vinegar" that is a microbiologically undefined starter culture obtained from spontaneous acetification of previous raw material. Selected starter cultures are the main technological improvement in order to innovate traditional balsamic vinegar production but until now they are rarely applied. To develop acetic acid bacteria starter cultures, selection criteria have to take in account composition of raw material, acetic acid bacteria metabolic activities, applied technology and desired characteristics of the final product. For traditional balsamic vinegar, significative phenotypical traits of acetic acid bacteria have been highlighted. Basic traits are: ethanol preferred and efficient oxidation, fast rate of acetic acid production, tolerance to high concentration of acetic acid, no overoxidation and low pH resistance. Specific traits are tolerance to high sugar concentration and to a wide temperature range. Gluconacetobacter europaeus and Acetobacter malorum strains can be evaluated to develop selected starter cultures since they show one or more suitable characters. PMID:18177968

Gullo, Maria; Giudici, Paolo

2008-06-30

8

Acetic acid bacteria and the production and quality of wine vinegar.  

PubMed

The production of vinegar depends on an oxidation process that is mainly performed by acetic acid bacteria. Despite the different methods of vinegar production (more or less designated as either "fast" or "traditional"), the use of pure starter cultures remains far from being a reality. Uncontrolled mixed cultures are normally used, but this review proposes the use of controlled mixed cultures. The acetic acid bacteria species determine the quality of vinegar, although the final quality is a combined result of technological process, wood contact, and aging. This discussion centers on wine vinegar and evaluates the effects of these different processes on its chemical and sensory properties. PMID:24574887

Mas, Albert; Torija, María Jesús; García-Parrilla, María del Carmen; Troncoso, Ana María

2014-01-01

9

Population dynamics of acetic acid bacteria during traditional wine vinegar production.  

PubMed

The population dynamics of acetic acid bacteria in traditional vinegar production was determined in two independent vinegar plants at both the species and strain level. The effect of barrels made of four different woods upon the population dynamics was also determined. Acetic acid bacteria were isolated on solid media and the species were identified by RFLP-PCR of 16S rRNA genes and confirmed by 16S rRNA gene sequencing, while strains were typed by ERIC-PCR and (GTG)(5)-rep-PCR. The most widely isolated species was Acetobacter pasteurianus, which accounted for 100% of all the isolates during most of the acetification. Gluconacetobacter europaeus only appeared at any notable level at the end of the process in oak barrels from one vinegar plant. The various A. pasteurianus strains showed a clear succession as the concentration of acetic acid increased. In both vinegar plants the relative dominance of different strains was modified as the concentrations of acetic acid increased, and strain diversity tended to reduce at the end of the process. PMID:20117853

Vegas, Carlos; Mateo, Estibaliz; González, Angel; Jara, Carla; Guillamón, José Manuel; Poblet, Montse; Torija, Ma Jesús; Mas, Albert

2010-03-31

10

Effect of different fertilization treatments on indole-3-acetic acid producing bacteria in soil  

Microsoft Academic Search

Purpose  Soil microorganisms directly affect the growth of plants. Especially, plant growth-promoting rhizobacteria (PGPR) play an\\u000a important role in plant growth. There are many studies about the effects of different fertilization treatments on soil microbial\\u000a community structure; however, the effects on PGPR, including indole-3-acetic acid (IAA)-producing bacteria have not been previously\\u000a reported. The objective of this study is to determine the

Chao-Lei Yuan; Cheng-Xiang Mou; Wen-Liang Wu; Yan-Bin Guo

2011-01-01

11

Rapid identification of acetic acid bacteria using MALDI-TOF mass spectrometry fingerprinting.  

PubMed

Acetic acid bacteria (AAB) are widespread microorganisms characterized by their ability to transform alcohols and sugar-alcohols into their corresponding organic acids. The suitability of matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF MS) for the identification of cultured AAB involved in the industrial production of vinegar was evaluated on 64 reference strains from the genera Acetobacter, Gluconacetobacter and Gluconobacter. Analysis of MS spectra obtained from single colonies of these strains confirmed their basic classification based on comparative 16S rRNA gene sequence analysis. MALDI-TOF analyses of isolates from vinegar cross-checked by comparative sequence analysis of 16S rRNA gene fragments allowed AAB to be identified, and it was possible to differentiate them from mixed cultures and non-AAB. The results showed that MALDI-TOF MS analysis was a rapid and reliable method for the clustering and identification of AAB species. PMID:23182036

Andrés-Barrao, Cristina; Benagli, Cinzia; Chappuis, Malou; Ortega Pérez, Ruben; Tonolla, Mauro; Barja, François

2013-03-01

12

Growth inhibitory effect of grape phenolics against wine spoilage yeasts and acetic acid bacteria.  

PubMed

This paper investigates the in vitro antimicrobial potential of 15 grape phenolic compounds of various chemical classes (phenolic acids, stilbenes and flavonoids) using the broth microdilution method against yeasts and acetic acid bacteria frequently occurring in deteriorated wine. Pterostilbene (MICs=32-128 ?g/mL), resveratrol (MICs=256-512 ?g/mL) and luteolin (MICs=256-512 ?g/mL) are among six active compounds that possessed the strongest inhibitory effects against all microorganisms tested. In the case of phenolic acids, myricetin, p-coumaric and ferulic acids exhibited selective antimicrobial activity (MICs=256-512 ?g/mL), depending upon yeasts and bacteria tested. In comparison with potassium metabisulphite, all microorganisms tested were more susceptible to the phenolics. The results revealed the antibacterial and antiyeast effects against wine spoilage microorganisms of several highly potent phenolics naturally occurring in grapes. These findings also provide arguments for further investigation of stilbenes as prospective compounds reducing the need for the use of sulphites in winemaking. PMID:23334100

Pastorkova, E; Zakova, T; Landa, P; Novakova, J; Vadlejch, J; Kokoska, L

2013-02-15

13

Acetic Acid Bacteria Genomes Reveal Functional Traits for Adaptation to Life in Insect Guts  

PubMed Central

Acetic acid bacteria (AAB) live in sugar rich environments, including food matrices, plant tissues, and the gut of sugar-feeding insects. By comparing the newly sequenced genomes of Asaia platycodi and Saccharibacter sp., symbionts of Anopheles stephensi and Apis mellifera, respectively, with those of 14 other AAB, we provide a genomic view of the evolutionary pattern of this bacterial group and clues on traits that explain the success of AAB as insect symbionts. A specific pre-adaptive trait, cytochrome bo3 ubiquinol oxidase, appears ancestral in AAB and shows a phylogeny that is congruent with that of the genomes. The functional properties of this terminal oxidase might have allowed AAB to adapt to the diverse oxygen levels of arthropod guts.

Chouaia, Bessem; Gaiarsa, Stefano; Crotti, Elena; Comandatore, Francesco; Degli Esposti, Mauro; Ricci, Irene; Alma, Alberto; Favia, Guido; Bandi, Claudio; Daffonchio, Daniele

2014-01-01

14

Utilization of Vinegar for Isolation of Cellulose Producing Acetic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Wastes of traditionally fermented Turkish vinegar were used in the isolation of cellulose producing acetic acid bacteria. Waste material was pre-enriched in Hestrin-Schramm medium and microorganisms were isolated by plating dilution series on HS agar plates The isolated strains were subjected to elaborate biochemical and physiological tests for identification. Test results were compared to those of reference strains Gluconacetobacter xylinus DSM 46604, Gluconacetobacter hansenii DSM 5602 and Gluconacetobacter liquefaciens DSM 5603. Seventeen strains, out of which only three were found to secrete the exopolysaccharide cellulose. The highest cellulose yield was recorded as 0.263+/-0.02 g cellulose L-1 for the strain AS14 which resembled Gluconacetobacter hansenii in terms of biochemical tests.

Aydin, Y. Andelib; Aksoy, Nuran Deveci

2010-06-01

15

Diversity of acetic acid bacteria present in healthy grapes from the Canary Islands.  

PubMed

The identification of acetic acid bacteria (AAB) from sound grapes from the Canary Islands is reported in the present study. No direct recovery of bacteria was possible in the most commonly used medium, so microvinifications were performed on grapes from Tenerife, La Palma and Lanzarote islands. Up to 396 AAB were isolated from those microvinifications and identified by 16S rRNA gene sequencing and phylogenetic analysis. With this method, Acetobacter pasteurianus, Acetobacter tropicalis, Gluconobacter japonicus and Gluconacetobacter saccharivorans were identified. However, no discrimination between the closely related species Acetobacter malorum and Acetobacter cerevisiae was possible. As previously described, 16S-23S rRNA gene internal transcribed spacer (ITS) region phylogenetic analysis was required to classify isolates as one of those species. These two species were the most frequently occurring, accounting for more than 60% of the isolates. For typing the AAB isolates, both the Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR and (GTG)5-PCR techniques gave similar resolution. A total of 60 profiles were identified. Thirteen of these profiles were found in more than one vineyard, and only one profile was found on two different islands (Tenerife and La Palma). PMID:21903289

Valera, Maria José; Laich, Federico; González, Sara S; Torija, Maria Jesús; Mateo, Estibaliz; Mas, Albert

2011-11-15

16

Dynamics and biodiversity of populations of lactic acid bacteria and acetic acid bacteria involved in spontaneous heap fermentation of cocoa beans in Ghana.  

PubMed

The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as "Weissella ghanaensis," was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named "Acetobacter senegalensis" (A. tropicalis-like) and "Acetobacter ghanaensis" (A. syzygii-like). PMID:17277227

Camu, Nicholas; De Winter, Tom; Verbrugghe, Kristof; Cleenwerck, Ilse; Vandamme, Peter; Takrama, Jemmy S; Vancanneyt, Marc; De Vuyst, Luc

2007-03-01

17

Strain typing of acetic acid bacteria responsible for vinegar production by the submerged elaboration method.  

PubMed

Strain typing of 103 acetic acid bacteria isolates from vinegars elaborated by the submerged method from ciders, wines and spirit ethanol, was carried on in this study. Two different molecular methods were utilised: pulsed field gel electrophoresis (PFGE) of total DNA digests with a number of restriction enzymes, and enterobacterial repetitive intergenic consensus (ERIC) - PCR analysis. The comparative study of both methods showed that restriction fragment PFGE of SpeI digests of total DNA was a suitable method for strain typing and for determining which strains were present in vinegar fermentations. Results showed that strains of the species Gluconacetobacter europaeus were the most frequent leader strains of fermentations by the submerged method in the studied vinegars, and among them strain R1 was the predominant one. Results showed as well that mixed populations (at least two different strains) occurred in vinegars from cider and wine, whereas unique strains were found in spirit vinegars, which offered the most stressing conditions for bacterial growth. PMID:20832673

Fernández-Pérez, Rocío; Torres, Carmen; Sanz, Susana; Ruiz-Larrea, Fernanda

2010-12-01

18

Gluconobacter as Well as Asaia Species, Newly Emerging Opportunistic Human Pathogens among Acetic Acid Bacteria ? †  

PubMed Central

Acetic acid bacteria (AAB) are broadly used in industrial food processing. Among them, members of the genera Asaia, Acetobacter, and Granulibacter were recently reported to be human opportunistic pathogens. We isolated AAB from clinical samples from three patients and describe here the clinical and bacteriological features of these cases. We report for the first time (i) the isolation of a Gluconobacter sp. from human clinical samples; (ii) the successive isolation of different AAB, i.e., an Asaia sp. and two unrelated Gluconobacter spp., from a cystic fibrosis patient; and (iii) persistent colonization of the respiratory tract by a Gluconobacter sp. in this patient. We reviewed the main clinical features associated with AAB isolation identified in the 10 documented reports currently available in the literature. Albeit rare, infections as well as colonization with AAB are increasingly reported in patients with underlying chronic diseases and/or indwelling devices. Clinicians as well as medical microbiologists should be aware of these unusual opportunistic pathogens, which are difficult to detect during standard medical microbiological investigations and which are multiresistant to antimicrobial agents. Molecular methods are required for identification of genera of AAB, but the results may remain inconclusive for identification to the species level.

Alauzet, Corentine; Teyssier, Corinne; Jumas-Bilak, Estelle; Gouby, Anne; Chiron, Raphael; Rabaud, Christian; Counil, Francois; Lozniewski, Alain; Marchandin, Helene

2010-01-01

19

Characterization of acetic acid bacteria in traditional acetic acid fermentation of rice vinegar (komesu) and unpolished rice vinegar (kurosu) produced in Japan.  

PubMed

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with Acetobacter pasteurianus. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation. PMID:11157275

Nanda, K; Taniguchi, M; Ujike, S; Ishihara, N; Mori, H; Ono, H; Murooka, Y

2001-02-01

20

Characterization of Acetic Acid Bacteria in Traditional Acetic Acid Fermentation of Rice Vinegar (Komesu) and Unpolished Rice Vinegar (Kurosu) Produced in Japan  

PubMed Central

Bacterial strains were isolated from samples of Japanese rice vinegar (komesu) and unpolished rice vinegar (kurosu) fermented by the traditional static method. Fermentations have never been inoculated with a pure culture since they were started in 1907. A total of 178 isolates were divided into groups A and B on the basis of enterobacterial repetitive intergenic consensus-PCR and random amplified polymorphic DNA fingerprinting analyses. The 16S ribosomal DNA sequences of strains belonging to each group showed similarities of more than 99% with Acetobacter pasteurianus. Group A strains overwhelmingly dominated all stages of fermentation of both types of vinegar. Our results indicate that appropriate strains of acetic acid bacteria have spontaneously established almost pure cultures during nearly a century of komesu and kurosu fermentation.

Nanda, Kumiko; Taniguchi, Mariko; Ujike, Satoshi; Ishihara, Nobuhiro; Mori, Hirotaka; Ono, Hisayo; Murooka, Yoshikatsu

2001-01-01

21

Acetate oxidation to CO 2 in anaerobic bacteria via a novel pathway not involving reactions of the citric acid cycle  

Microsoft Academic Search

In several sulfate-reducing bacteria capable of complete oxidation of acetate (or acetyl CoA), the citric acid cycle is not operative. No 2-oxoglutarate dehydrogenase activity was found in these organisms, and the labelling pattern of oxaloacetate excludes its synthesis via 2-oxo-glutarate. These sulfate-reducers contained, however, high activities of the enzymes carbon monoxide dehydrogenase and formate dehydrogenase and catalyzed an isotope exchange

Rolf Schauder; Bernhard Eikmanns; Rudolf K. Thauer; Fritz Widdel; Georg Fuchs

1986-01-01

22

Identification of acetic acid bacteria isolated from Indonesian sources, especially of isolates classified in the genus Gluconobacter.  

PubMed

Sixty-four strains of acetic acid bacteria were isolated from Indonesian sources such as fruits, flowers, and fermented foods by the enrichment culture at pH 3.5. Forty-five strains were routinely identified as Acetobacter strains because of their oxidation of acetate and lactate to carbon dioxide and water and their Q-9 isoprenolog, corresponding to 70% of all the 64 acetic acid bacteria isolated. Eight isolates were identified as Gluconacetobacter strains because of their oxidation of acetate and lactate and their Q-10 isoprenolog, occupying 13% of all the isolates. The remaining 11 isolates, accommodated in the genus Gluconobacter because of no oxidation of acetate and lactate and because of their Q-10 isoprenolog, accounted for 17% of all the isolates. They were divided into two groups based on DNA base compositions. One comprised the seven isolates, which had high G1C contents of DNA ranging from 60.3 to 63.5 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter oxydans at values of 64-94% of DNA relatedness. The other comprised the remaining four isolates, which had low G+C contents of DNA ranging from 57.5 to 57.7 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter frateurii at values of 63-77% of DNA relatedness. The high values of DNA relatedness, 84 to 96%, were obtained between the type strains of Gluconobacter cerinus and Gluconobacter asaii. PMID:12501398

Yamada, Yuzo; Hosono, Reiko; Lisdyanti, Puspita; Widyastuti, Yantyati; Saono, Susono; Uchimura, Tai; Komagata, Kazuo

1999-02-01

23

Genetic characteristics of cellulose-forming acetic acid bacteria identified phenotypically as Gluconacetobacter xylinus.  

PubMed

Gluconacetobacter xylinus (=Acetobacter xylinum) shows variety in acid formation from sugars and sugar-alcohols. Toyosaki et al. proposed new subspecies of G. xylinus (=Acetobacter xylinum) subsp. sucrofermentans in point of acid formation from sucrose and a homology index of 58.2% with the type strain of G. xylinus subsp. xylinus in DNA-DNA hybridization experiments. We tried DNA-DNA hybridization to clarify relationship between acid formation from sugars and classification of G. xylinus. The G + C contents of G. xylinus showed 60.1-62.4 mol% with a range of 2.3 mol%. When type strains of G. xylinus subsp. xylinus, G. xylinus subsp. sucrofermentans, and IFO 3288 forming acid from sucrose, were used as probes, the DNAs from three strains showed 67-100%, 64-89%, and 60-100% similarity to those from sixteen strains including bacteria that form acid from sucrose or not. These results show that homology indexes do not reflect differences of acid formation from sucrose. As a results, the species G. xylinus was proved to be genetically homogeneous. PMID:10830489

Tanaka, M; Murakami, S; Shinke, R; Aoki, K

2000-04-01

24

Gluconacetobacter medellinensis sp. nov., cellulose- and non-cellulose-producing acetic acid bacteria isolated from vinegar.  

PubMed

The phylogenetic position of a cellulose-producing acetic acid bacterium, strain ID13488, isolated from commercially available Colombian homemade fruit vinegar, was investigated. Analyses using nearly complete 16S rRNA gene sequences, nearly complete 16S-23S rRNA gene internal transcribed spacer (ITS) sequences, as well as concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, allocated the micro-organism to the genus Gluconacetobacter, and more precisely to the Gluconacetobacter xylinus group. Moreover, the data suggested that the micro-organism belongs to a novel species in this genus, together with LMG 1693(T), a non-cellulose-producing strain isolated from vinegar by Kondo and previously classified as a strain of Gluconacetobacter xylinus. DNA-DNA hybridizations confirmed this finding, revealing a DNA-DNA relatedness value of 81?% between strains ID13488 and LMG 1693(T), and values <70?% between strain LMG 1693(T) and the type strains of the closest phylogenetic neighbours. Additionally, the classification of strains ID13488 and LMG 1693(T) into a single novel species was supported by amplified fragment length polymorphism (AFLP) and (GTG)5-PCR DNA fingerprinting data, as well as by phenotypic data. Strains ID13488 and LMG 1693(T) could be differentiated from closely related species of the genus Gluconacetobacter by their ability to produce 2- and 5-keto-d-gluconic acid from d-glucose, their ability to produce acid from sucrose, but not from 1-propanol, and their ability to grow on 3?% ethanol in the absence of acetic acid and on ethanol, d-ribose, d-xylose, sucrose, sorbitol, d-mannitol and d-gluconate as carbon sources. The DNA G+C content of strains ID13488 and LMG 1693(T) was 58.0 and 60.7 mol%, respectively. The major ubiquinone of LMG 1693(T) was Q-10. Taken together these data indicate that strains ID13488 and LMG 1693(T) represent a novel species of the genus Gluconacetobacter for which the name Gluconacetobacter medellinensis sp. nov. is proposed. The type strain is LMG 1693(T) (?=?NBRC 3288(T)?=?Kondo 51(T)). PMID:22729025

Castro, Cristina; Cleenwerck, Ilse; Trcek, Janja; Zuluaga, Robin; De Vos, Paul; Caro, Gloria; Aguirre, Ricardo; Putaux, Jean-Luc; Gañán, Piedad

2013-03-01

25

Application of culture culture-independent molecular biology based methods to evaluate acetic acid bacteria diversity during vinegar processing.  

PubMed

Acetic acid bacteria (AAB) are considered fastidious microorganisms because they are difficult to isolate and cultivate. Different molecular approaches were taken to detect AAB diversity, independently of their capacity to grow in culture media. Those methods were tested in samples that originated during traditional vinegar production. Bacterial diversity was assessed by analysis of 16S rRNA gene, obtained by PCR amplifications of DNA extracted directly from the acetification container. Bacterial composition was analyzed by RFLP-PCR of 16S rRNA gene, Temporal Temperature Gradient Gel Electrophoresis (TTGE) separation of amplicons containing region V3-V5 of 16S rRNA gene and cloning of those amplicons. TTGE bands and clones were grouped based on their electrophoretic pattern similarity and sequenced to be compared with reference strains. The main microorganism identified in vinegar was Acetobacter pasteurianus, which at the end of the acetification process was considered to be the only microorganism present. The diversity was the highest at 2% acetic acid, where indefinite species of Gluconacetobacter xylinus/europaeus/intermedius were also present. PMID:18571262

Ilabaca, Carolina; Navarrete, Paola; Mardones, Pamela; Romero, Jaime; Mas, Albert

2008-08-15

26

Occurrence of indole-3-acetic Acid-producing bacteria on pear trees and their association with fruit russet.  

PubMed

ABSTRACT A relatively high percentage of epiphytic bacteria on pear leaf and fruit surfaces had the ability to produce indole-3-acetic acid (IAA) in culture media supplemented with tryptophan. While over 50% of the strains produced at least small amounts of IAA in culture, about 25% of the strains exhibited high IAA production as evidenced by both colorimetric and high-performance liquid chromatography analysis of culture supernatants. A majority of the strains that produced high amounts of IAA were identified as Erwinia herbicola (Pantoea agglomerans), while some strains of Pseudomonas syringae, Pseudomonas viridiflava, Pseudomonas fluorescens, Pseudomonas putida, and Rahnella aquaticus that produced high amounts of IAA also were found on pear. Fruit russeting was significantly increased in 39 out of 46 trials over an 8-year period in which IAA-producing bacteria were applied to trees compared with control trees. A linear relationship was observed between fruit russet severity and the logarithm of the population size of different IAA-producing bacteria on trees in the 30 days after inoculation, when normalized for the amount of IAA produced by each strain in culture. On average, the severity of fruit russet was only about 77% that on control trees when trees were treated at the time of bloom with Pseudomonas fluorescens strain A506, which does not produce IAA. Both total bacterial populations on pear in the 30-day period following full bloom and fruit russet severity varied greatly from year to year and in different commercial orchards over a 10-year period. There was a strong linear correlation between the logarithm of total bacterial population sizes and fruit russet severity. PMID:18944847

Lindow, S E; Desurmont, C; Elkins, R; McGourty, G; Clark, E; Brandl, M T

1998-11-01

27

Genus-specific profile of acetic acid bacteria by 16S rDNA PCR-DGGE.  

PubMed

An effective method for grouping acetic acid bacteria (AAB) genera was defined and evaluated as a tool for preliminary screening of the major AAB species involved in vinegar production. Acetobacter, Gluconobacter, Gluconacetobacter, Asaia, Neoasaia, Saccharibacter, Frateuria and Kozakia AAB strains were screened on the basis of the 16S rDNA sequences using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique. The DGGE profile of all the strains tested, consisted of one single band of approximately 330 bp for each strain and allowed their clustering. The results obtained clearly reflected in silico phylogenetic analysis of the AAB species used in this study, in fact, the species with a higher 16S rDNA sequence homology showed a similar electrophoretic profile. In particular almost all the species belonging to the genus Gluconacetobacter showed a DGGE pattern nearly identical and well distinct from all the other AAB genera. Furthermore by PCR-DGGE it was possible to clearly group the species more frequently recovered from vinegar fermentation which are mainly distributed in the genera Acetobacter, Gluconobacter and Gluconacetobacter. PMID:17919758

De Vero, Luciana; Giudici, Paolo

2008-06-30

28

Aromatic amino acid aminotransferase activity and indole-3-acetic acid production by associative nitrogen-fixing bacteria.  

PubMed

In this work, we report the detection of aromatic amino acid aminotransferase (AAT) activity from cell-free crude extracts of nine strains of N(2)-fixing bacteria from three genera. Using tyrosine as substrate, AAT activity ranged in specific activity from 0.084 to 0.404 micromol min(-1)mg(-1). When analyzed under non-denaturating PAGE conditions; and using tryptophan, phenylalanine, tyrosine, and histidine as substrates Pseudomonas stutzeri A15 showed three isoforms with molecular mass of 46, 68 and 86 kDa, respectively; Azospirillum strains displayed two isoforms which molecular mass ranged from 44 to 66 kDa and Gluconacetobacter strains revealed one enzyme, which molecular mass was estimated to be much more higher than those of Azospirillum and P. stutzeri strains. After SDS-PAGE, some AAT activity was lost, indicating a differential stability of proteins. All the strains tested produced IAA, especially with tryptophan as precursor. Azospirillum strains produced the highest concentrations of IAA (16.5-38 microg IAA/mg protein), whereas Gluconacetobacter and P. stutzeri strains produced lower concentrations of IAA ranging from 1 to 2.9 microg/mg protein in culture medium supplemented with tryptophan. The IAA production may enable bacteria promote a growth-promoting effect in plants, in addition to their nitrogen fixing ability. PMID:15043864

Pedraza, Raúl Osvaldo; Ramírez-Mata, Alberto; Xiqui, Ma Luisa; Baca, Beatriz Eugenia

2004-04-01

29

Novel nitrogen-fixing acetic acid bacteria, Gluconacetobacter johannae sp. nov. and Gluconacetobacter azotocaptans sp. nov., associated with coffee plants.  

PubMed

Diazotrophic bacteria were isolated, in two different years, from the rhizosphere and rhizoplane of coffee (Coffea arabica L.) plants cultivated in Mexico; they were designated as type DOR and type SAd isolates. They showed characteristics of the family Acetobacteraceae, having some features in common with Gluconacetobacter (formerly Acetobacter) diazotrophicus, the only known N2-fixing species of the acetic acid bacteria, but they differed from this species with regard to several characteristics. Type DOR isolates can be differentiated phenotypically from type SAd isolates. Type DOR isolates and type SAd isolates can both be differentiated from Gluconacetobacter diazotrophicus by their growth features on culture media, their use of amino acids as nitrogen sources and their carbon-source usage. These results, together with the electrophoretic mobility patterns of metabolic enzymes and amplified rDNA restriction analysis, suggested that the type DOR and type SAd isolates represent two novel N2-fixing species. Comparative analysis of the 16S rRNA sequences revealed that strains CFN-Cf55T (type DOR isolate) and CFN-Ca54T (type SAd isolate) were closer to Gluconacetobacter diazotrophicus (both strains had sequence similarities of 98.3%) than to Gluconacetobacter liquefaciens, Gluconacetobacter sacchari (similarities < 98%) or any other acetobacteria. Strain CFN-Cf55T exhibited low levels of DNA-DNA reassociation with type SAd isolates (mean 42%) and strain CFN-Ca54T exhibited mean DNA-DNA reassociation of 39.5% with type DOR isolates. Strains CFN-Cf55T and CFN-Ca54T exhibited very low DNA reassociation levels, 7-21%, with other closely related acetobacterial species. On the basis of these results, two novel N2-fixing species are proposed for the family Acetobacteraceae, Gluconacetobacter johannae sp. nov. (for the type DOR isolates), with strain CFN-Cf55T (= ATCC 700987T = DSM 13595T) as the type strain, and Gluconacetobacter azotocaptans sp. nov. (for the type SAd isolates), with strain CFN-Ca54T (= ATCC 70098ST = DSM 13594T) as the type strain. PMID:11491326

Fuentes-Ramírez, L E; Bustillos-Cristales, R; Tapia-Hernández, A; Jiménez-Salgado, T; Wang, E T; Martínez-Romero, E; Caballero-Mellado, J

2001-07-01

30

Acetate Production by Methanogenic Bacteria  

PubMed Central

Methanosarcina barkeri MS and 227 and Methanosarcina mazei S-6 produced acetate when grown on H2-CO2, methanol, or trimethylamine. Marked differences in acetate production by the two bacterial species were found, even though methane and cell yields were nearly the same. M. barkeri produced 30 to 75 ?mol of acetate per mmol of CH4 formed, but M. mazei produced only 8 to 9 ?mol of acetate per mmol of CH4.

Westermann, Peter; Ahring, Birgitte K.; Mah, Robert A.

1989-01-01

31

Identification and characterization of thermotolerant acetic acid bacteria strains isolated from coconut water vinegar in Sri Lanka.  

PubMed

From the pellicle formed on top of brewing coconut water vinegar in Sri Lanka, three Acetobacter strains (SL13E-2, SL13E-3, and SL13E-4) that grow at 42?°C and four Gluconobacter strains (SL13-5, SL13-6, SL13-7, and SL13-8) grow at 37?°C were identified as Acetobacter pasteurianus and Gluconobacter frateurii, respectively. Acetic acid production by the isolated Acetobacter strains was examined. All three strains gave 4% acetic acid from 6% initial ethanol at 37?°C, and 2.5% acetic acid from 4% initial ethanol at 40?°C. Compared with the two other strains, SL13E-4 showed both slower growth and slower acetic acid production. As well as the thermotolerant SKU1108 strain, the activities of the alcohol dehydrogenase and the aldehyde dehydrogenase of SL13E-2 and SL13E-4 were more stable than those of the mesophilic strain. The isolated strains were used to produce coconut water vinegar at higher temperatures than typically used for vinegar production. PMID:25036846

Perumpuli, P A B N; Watanabe, Taisuke; Toyama, Hirohide

2014-03-01

32

Growth/no growth models describing the influence of pH, lactic and acetic acid on lactic acid bacteria developed to determine the stability of acidified sauces.  

PubMed

Growth/no growth models were developed for two spoilage bacteria typical for acidified sauces, L. plantarum and L. fructivorans. Influencing factors embedded in the model are also those typically encountered in these acidified sauces. The pH was varied between 3.0 and 5.0 (5 levels), and the acetic and lactic acid concentration ranged from 0 to 3% (6 levels). Modified MRS broth was inoculated at a high inoculation level (10(6) CFU/ml), incubated at 30 degrees C and growth was assessed by optical density measurements. All combinations of environmental conditions were tested in twelvefold yielding precise values for the probability of growth. Data were modelled by means of ordinary logistic regression. A comparison was made between a model containing the total acid concentrations as explanatory variables, on the one hand, and a model differentiating between the dissociated and undissociated concentrations, on the other hand. Results showed that (i) L. plantarum and L. fructivorans behave differently, resulting in a clearly distinct growth/no growth interface, (ii) there was no great difference between the established models with different explanatory variables, (iii) in some cases, growth/no growth boundaries at very low probabilities (which are more practical in industry) show illogical behaviour. The results of this study were also compared with the CIMSCEE code, which is often used by food producers to determine the stability of their acidified food products. PMID:17868939

Vermeulen, A; Devlieghere, F; Bernaerts, K; Van Impe, J; Debevere, J

2007-11-01

33

Occurrence of enzymes involved in biosynthesis of indole-3-acetic acid from indole-3-acetonitrile in plant-associated bacteria, Agrobacterium and Rhizobium.  

PubMed Central

The occurrence of a hitherto unknown pathway involving the action of two enzymes, a nitrile hydratase and an amidase for the biosynthesis of indole-3-acetic acid was discovered in phytopathogenic bacteria Agrobacterium tumefaciens and in leguminous bacteria Rhizobium. The nitrile hydratase acting on indole-3-acetonitrile was purified to homogeneity through only two steps from the cell-free extract of A. tumefaciens. The molecular mass of the purified enzyme estimated by HPLC was about 102 kDa, and the enzyme consisted of four subunits identical in molecular mass. The enzyme exhibited a broad absorption spectrum in the visible range with absorption maxima at 408 nm and 705 nm, and it contained cobalt and iron. The enzyme stoichiometrically catalyzed the hydration of indole-3-acetonitrile into indole-3-acetamide with a specific activity of 13.7 mol per min per mg and a Km of 7.9 microM. Images Fig. 1

Kobayashi, M; Suzuki, T; Fujita, T; Masuda, M; Shimizu, S

1995-01-01

34

Growth of Brassica juncea under chromium stress: influence of siderophores and indole 3 acetic acid producing rhizosphere bacteria.  

PubMed

Plant growth promoting rhizobacterial (PGPR) strains A3 and S32 have been shown to promote the growth of Brassica juncea under chromium stress which has been related to the microbial production of siderophores and indole 3 acetic acid (IAA). The aim of the present study is to evaluate the importance of siderophores and IAA producing PGPR on the growth of Brassica juncea under chromium stress. The production of IAA and siderophores were observed in the strains A3 and S32, respectively. Both PGPR strains promote the growth of Brassica juncea under chromium stress. The maximum growth was observed in plants inoculated with siderophores producing strain 32. Both the bacterial inoculum did not influence the uptake of chromium by plants. The present observation showed that PGPR isolates A3 and S32 are capable of protecting the plants against the inhibitory effects of chromium by producing the siderophores and IAA. PMID:16459559

Rajkumar, M; Lee, Kui Jae; Lee, Wang Hyu; Banu, J Rajesh

2005-10-01

35

Metabolic Activity of Fatty Acid-Oxidizing Bacteria and the Contribution of Acetate, Propionate, Butyrate, and CO2 to Methanogenesis in Cattle Waste at 40 and 60?C  

PubMed Central

The quantitative contribution of fatty acids and CO2 to methanogenesis was studied by using stirred, 3-liter bench-top digestors fed on a semicontinuous basis with cattle waste. The fermentations were carried out at 40 and 60°C under identical loading conditions (6 g of volatile solids per liter of reactor volume per day, 10-day retention time). In the thermophilic digestor, acetate turnover increased from a prefeeding level of 16 ?M/min to a peak (49 ?M/min) 1 h after feeding and then gradually decreased. Acetate turnover in the mesophilic digestor increased from 15 to 40 ?M/min. Propionate turnover ranged from 2 to 5.2 and 1.5 to 4.5 ?M/min in the thermophilic and mesophilic digestors, respectively. Butyrate turnover (0.7 to 1.2 ?M/min) was similar in both digestors. The proportion of CH4 produced via the methyl group of acetate varied with time after feeding and ranged from 72 to 75% in the mesophilic digestor and 75 to 86% in the thermophilic digestor. The contribution from CO2 reduction was 24 to 29% and 19 to 27%, respectively. Propionate and butyrate turnover accounted for 20% of the total CH4 produced. Acetate synthesis from CO2 was greatest shortly after feeding and was higher in the thermophilic digestor (0.5 to 2.4 ?M/min) than the mesophilic digestor (0.3 to 0.5 ?M/min). Counts of fatty acid-degrading bacteria were related to their turnover activity.

Mackie, Roderick I.; Bryant, Marvin P.

1981-01-01

36

Genome sequences of the high-acetic acid-resistant bacteria Gluconacetobacter europaeus LMG 18890T and G. europaeus LMG 18494 (reference strains), G. europaeus 5P3, and Gluconacetobacter oboediens 174Bp2 (isolated from vinegar).  

PubMed

Bacteria of the genus Gluconacetobacter are usually involved in the industrial production of vinegars with high acetic acid concentrations. We describe here the genome sequence of three Gluconacetobacter europaeus strains, a very common bacterial species from industrial fermentors, as well as of a Gluconacetobacter oboediens strain. PMID:21441523

Andrés-Barrao, Cristina; Falquet, Laurent; Calderon-Copete, Sandra P; Descombes, Patrick; Ortega Pérez, Ruben; Barja, François

2011-05-01

37

Analysis of several methods for the extraction of high quality DNA from acetic acid bacteria in wine and vinegar for characterization by PCR-based methods.  

PubMed

Acetic acid bacteria (AAB) are fastidious microorganisms with poor recovery in culture. Culture-independent methods are currently under examination. Good DNA extraction is a strict requirement of these methods. We compared five methods for extracting the DNA of AAB directly from wine and vinegar samples. Four matrices (white wine, red wine, superficial vinegar and submerged vinegar) contaminated with two AAB strains belonging to Acetobacter pasteurianus and Gluconacetobacter hansenii were assayed. To improve the yield and quality of the extracted DNA, a sample treatment (washing with polyvinyl pyrrolidone or NaCl) was also tested. DNA quality was measured by amplification of the 16S rRNA gene with conventional PCR. DNA recovery rate was assessed by real-time PCR. DNA amplification was always successful with the Wizard method though DNA recovery was poor. A CTAB-based method and NucleoSpin protocol extracted the highest DNA recoveries from wine and vinegar samples. Both of these methods require treatment to recover suitable DNA for amplification with maximum recovery. Both may therefore be good solutions for DNA extraction in wine and vinegar samples. DNA extraction of Ga hansenii was more effective than that of A. pasteurianus. The fastest and cheapest method we evaluated (the Thermal shock protocol) produced the worst results both for DNA amplification and DNA recovery. PMID:18950887

Jara, C; Mateo, E; Guillamón, J M; Torija, M J; Mas, A

2008-12-10

38

Effects of growth medium on matrix-assisted laser desorption-ionization time of flight mass spectra: a case study of acetic acid bacteria.  

PubMed

The effect of the growth medium used on the matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectra generated and its consequences for species and strain level differentiation of acetic acid bacteria (AAB) were determined by using a set of 25 strains. The strains were grown on five different culture media that yielded a total of more than 600 mass spectra, including technical and biological replicates. The results demonstrate that the culture medium can have a profound effect on the mass spectra of AAB as observed in the presence and varying signal intensities of peak classes, in particular when culture media do not sustain optimal growth. The observed growth medium effects do not disturb species level differentiation but strongly affect the potential for strain level differentiation. The data prove that a well-constructed and robust MALDI-TOF mass spectrometry identification database should comprise mass spectra of multiple reference strains per species grown on different culture media to facilitate species and strain level differentiation. PMID:24362425

Wieme, Anneleen D; Spitaels, Freek; Aerts, Maarten; De Bruyne, Katrien; Van Landschoot, Anita; Vandamme, Peter

2014-02-01

39

Pyruvate-associated Acid resistance in bacteria.  

PubMed

Glucose confers acid resistance on exponentially growing bacteria by repressing formation of the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex and consequently activating acid resistance genes. Therefore, in a glucose-rich growth environment, bacteria are capable of resisting acidic stresses due to low levels of cAMP-CRP. Here we reveal a second mechanism for glucose-conferred acid resistance. We show that glucose induces acid resistance in exponentially growing bacteria through pyruvate, the glycolysis product. Pyruvate and/or the downstream metabolites induce expression of the small noncoding RNA (sncRNA) Spot42, and the sncRNA, in turn, activates expression of the master regulator of acid resistance, RpoS. In contrast to glucose, pyruvate has little effect on levels of the cAMP-CRP complex and does not require the complex for its effects on acid resistance. Another important difference between glucose and pyruvate is that pyruvate can be produced by bacteria. This means that bacteria have the potential to protect themselves from acidic stresses by controlling glucose-derived generation of pyruvate, pyruvate-acetate efflux, or reversion from acetate to pyruvate. We tested this possibility by shutting down pyruvate-acetate efflux and found that the resulting accumulation of pyruvate elevated acid resistance. Many sugars can be broken into glucose, and the subsequent glycolysis generates pyruvate. Therefore, pyruvate-associated acid resistance is not confined to glucose-grown bacteria but is functional in bacteria grown on various sugars. PMID:24795365

Wu, Jianting; Li, Yannan; Cai, Zhiming; Jin, Ye

2014-07-15

40

Cytenamide acetic acid solvate  

PubMed Central

In the crystal structure of the title compound (systematic name: 5H-dibenzo[a,d]cyclo­hepta­triene-5-carboxamide ethanoic acid solvate), C16H13NO·C2H4O2, the cytenamide and solvent mol­ecules form a hydrogen-bonded R 2 2(8) dimer motif, which is further connected to form a centrosymmetric double ring motif arrangement. The cycloheptene ring adopts a boat conformation and the dihedral angle between the least-squares planes through the two aromatic rings is 54.7?(2)°.

Johnston, Andrea; Florence, Alastair J.; Fabianni, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.

2008-01-01

41

Influence of Turning and Environmental Contamination on the Dynamics of Populations of Lactic Acid and Acetic Acid Bacteria Involved in Spontaneous Cocoa Bean Heap Fermentation in Ghana  

Microsoft Academic Search

The influence of turning and environmental contamination on six spontaneous cocoa bean heap fermenta- tions performed in Ghana was studied through a multiphasic approach, encompassing both microbiological (culture-dependent and culture-independent techniques) and metabolite target analyses. A sensory analysis of chocolate made from the fermented, dried beans was performed as well. Only four clusters were found among the isolates of acetic

Nicholas Camu; Angel Gonzalez; Tom De Winter; Ann Van Schoor; Katrien De Bruyne; Peter Vandamme; Jemmy S. Takrama; Solomon K. Addo; Luc De Vuyst

2008-01-01

42

Investigation on isobaric vapor liquid equilibrium for acetic acid + water + ( n-propyl acetate or iso-butyl acetate)  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+n-propyl acetate, acetic acid+iso-butyl acetate, acetic acid+water+n-propyl acetate, acetic acid+water+iso-butyl acetate are measured at 101.33kPa with a modified Rose still. The nonideal behavior in vapor phase caused by the association of acetic acid are corrected by the chemical theory and Hayden–O’Connell method, and analyzed by calculating the second virial coefficients and

Chundong Zhang; Hui Wan; Lijun Xue; Guofeng Guan

2011-01-01

43

Carbohydrate metabolism in lactic acid bacteria  

Microsoft Academic Search

The term “lactic acid bacteria” is discussed. An overview of the following topics is given: main pathways of homo- and heterofermentation of hexoses, i.e. glycolysis, bifidus pathway, 6-phosphogluconate pathway; uptake and dissimilation of lactose (tagatose pathway); fermentation of pentoses and pentitols; alternative fates of pyruvate, i.e. splitting to formate and acetate, CO2 and acetate or formation of acetoin and diacetyl;

Otto Kandler

1983-01-01

44

Contribution of acetate to butyrate formation by human faecal bacteria.  

PubMed

Acetate is normally regarded as an endproduct of anaerobic fermentation, but butyrate-producing bacteria found in the human colon can be net utilisers of acetate. The butyrate formed provides a fuel for epithelial cells of the large intestine and influences colonic health. [1-(13)C]Acetate was used to investigate the contribution of exogenous acetate to butyrate formation. Faecalibacterium prausnitzii and Roseburia spp. grown in the presence of 60 mm-acetate and 10 mm-glucose derived 85-90 % butyrate-C from external acetate. This was due to rapid interchange between extracellular acetate and intracellular acetyl-CoA, plus net acetate uptake. In contrast, a Coprococcus-related strain that is a net acetate producer derived only 28 % butyrate-C from external acetate. Different carbohydrate-derived energy sources affected butyrate formation by mixed human faecal bacteria growing in continuous or batch cultures. The ranking order of butyrate production rates was amylopectin > oat xylan > shredded wheat > inulin > pectin (continuous cultures), and inulin > amylopectin > oat xylan > shredded wheat > pectin (batch cultures). The contribution of external acetate to butyrate formation in these experiments ranged from 56 (pectin) to 90 % (xylan) in continuous cultures, and from 72 to 91 % in the batch cultures. This is consistent with a major role for bacteria related to F. prausnitzii and Roseburia spp. in butyrate formation from a range of substrates that are fermented in the large intestine. Variations in the dominant metabolic type of butyrate producer between individuals or with variations in diet are not ruled out, however, and could influence butyrate supply in the large intestine. PMID:15182395

Duncan, Sylvia H; Holtrop, Grietje; Lobley, Gerald E; Calder, A Graham; Stewart, Colin S; Flint, Harry J

2004-06-01

45

Oxidative reaction of oxindole-3-acetic acids.  

PubMed

The oxindole-3-acetic acids, oxidative metabolites of indole-3-acetic acid, were isolated from a byproduct of a corn starch manufacturing plant, and were further converted to the 3-hydroxyl derivatives in the presence of metal ion. The mechanical study was followed by a chemical analysis including other byproducts, and suggested the presence of an intermediate that had a radical at the C-3 position of oxindole-3-acetic acids. PMID:14519969

Niwa, Toshio; Ishii, Sayuri; Hiramatsu, Atsushi; Osawa, Toshihiko

2003-09-01

46

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

47

Metabolic activity of fatty acid-oxidizing bacteria and the contribution of acetate, propionate, butyrate, and CO/sub 2/ to methanogenesis in cattle waste at 40 and 60/sup 0/C  

SciTech Connect

The quantitative contribution of fatty acids and CO/sub 2/ to methanogenesis was studied by using stirred, 3-liter bench-top digestors fed on a semicontinuous basis with cattle waste. The fermentations were carried out at 40 and 60/sup 0/C under identical loading conditions. In the thermophilic digestor, acetate turnover increased from a prefeeding level of 16 ..mu..M/min to a peak (49 ..mu..M/min. Acetate turnover in the mesophilic digester increased fron 15 to 40 ..mu..M/min. Propionate turnover ranged from 2 to 5.2 and 1.5 to 4.5 ..mu..M/min in the thermophilic and mesophilic digestors, respectively. Butyrate turnover (0.7 to 1.2 ..mu..M/min) was similar in both digestors. The proportion of CH/sub 4/ produced via the methyl group of acetate varied with time after feeding and ranged from 72 to 75% in the mesophilic digestor and 75 to 86% in the thermophilic digestor. The contribution from CO/sub 2/ reduction was 24 to 19% and 19 to 27%, respectively. Propionate and butyrate turnover accounted for 20% of the total CH/sub 4/ produced. Counts of fatty acid-degrading bacteria were related to their turnover activity.

Mackie, R.I.; Bryant, M.P.

1981-06-01

48

Acetate utilization and butyryl coenzyme A (CoA):acetate-CoA transferase in butyrate-producing bacteria from the human large intestine.  

PubMed

Seven strains of Roseburia sp., Faecalibacterium prausnitzii, and Coprococcus sp. from the human gut that produce high levels of butyric acid in vitro were studied with respect to key butyrate pathway enzymes and fermentation patterns. Strains of Roseburia sp. and F. prausnitzii possessed butyryl coenzyme A (CoA):acetate-CoA transferase and acetate kinase activities, but butyrate kinase activity was not detectable either in growing or in stationary-phase cultures. Although unable to use acetate as a sole source of energy, these strains showed net utilization of acetate during growth on glucose. In contrast, Coprococcus sp. strain L2-50 is a net producer of acetate and possessed detectable butyrate kinase, acetate kinase, and butyryl-CoA:acetate-CoA transferase activities. These results demonstrate that different functionally distinct groups of butyrate-producing bacteria are present in the human large intestine. PMID:12324374

Duncan, Sylvia H; Barcenilla, Adela; Stewart, Colin S; Pryde, Susan E; Flint, Harry J

2002-10-01

49

Atmospheric oxidation pathways of acetic acid.  

PubMed

One of the most abundant carboxylic acids measured in the atmosphere is acetic acid (CH(3)C(O)OH), present in rural, urban, and remote marine environments in the low-ppb range. Acetic acid concentrations are not well reproduced in global 3-D atmospheric models because of the poor inventory of sources and sinks to model its global distribution. To understand the complete oxidation of acetic acid in the atmosphere initiated by OH radicals, ab initio calculations are performed to describe in detail the energetics of the reaction potential energy surface (PES). The proposed reaction mechanism suggests that the CH(3)C(O)OH + OH reaction takes place via three pathways: the addition of OH to the central carbon, the abstraction of a methyl hydrogen, and the abstraction of an acidic hydrogen. The PES is characterized by prereactive H-complexes, transition states, and more interestingly unique radical-mediated isomerization reactions. From the analysis of the energetics, acetic acid atmospheric oxidation will proceed mainly via the abstraction of the acidic hydrogen, consistent with previous experimental and theoretical studies. The major byproducts from each pathway are identified. Glyoxylic acid is suggested to be a major byproduct of the atmospheric oxidation of acetic acid. The atmospheric fate of glyoxylic acid is discussed. PMID:16571046

Rosado-Reyes, Claudette M; Francisco, Joseph S

2006-04-01

50

Bacteria contributing to behaviour of radiocarbon in sodium acetate.  

PubMed

An acetate-utilising bacterium was isolated and identified from deionised water that was used for flooding of paddy soils in this study's batch culture experiments. Bacteria in the deionised water samples formed colonies on agar plates containing [1,2-(14)C] sodium acetate, and the autoradiograms showed that all the colonies were positive for (14)C utilisation. Then one of the acetate-utilising bacteria was isolated. The isolate was characterised by phylogenetic analysis, cell morphology, Gram staining and growth at 30 °C. Phylogenetic analysis based on 16S rRNA sequencing showed that the isolate belonged to the genus Burkholderia. The bacterium was gram-negative rods and grew at 30 °C under aerobic conditions. Based on these characteristics, the isolate was identified as Burkholderia gladioli. Because B. gladioli is often found in soil, water and the rhizosphere, attention must be paid to the relationships between bacteria and the behaviour of (14)C to for the safety assessment of geological disposal of transuranic waste. PMID:21561944

Ishii, Nobuyoshi; Uchida, Shigeo

2011-07-01

51

Dynamic Protonation Equilibrium of Solvated Acetic Acid  

SciTech Connect

For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

2007-04-13

52

Quick identification of acetic acid bacteria based on nucleotide sequences of the 16S-23S rDNA internal transcribed spacer region and of the PQQ-dependent alcohol dehydrogenase gene.  

PubMed

Acetic acid bacteria (AAB) are well known for oxidizing different ethanol-containing substrates into various types of vinegar. They are also used for production of some biotechnologically important products, such as sorbose and gluconic acids. However, their presence is not always appreciated since certain species also spoil wine, juice, beer and fruits. To be able to follow AAB in all these processes, the species involved must be identified accurately and quickly. Because of inaccuracy and very time-consuming phenotypic analysis of AAB, the application of molecular methods is necessary. Since the pairwise comparison among the 16S rRNA gene sequences of AAB shows very high similarity (up to 99.9%) other DNA-targets should be used. Our previous studies showed that the restriction analysis of 16S-23S rDNA internal transcribed spacer region is a suitable approach for quick affiliation of an acetic acid bacterium to a distinct group of restriction types and also for quick identification of a potentially novel species of acetic acid bacterium (Trcek & Teuber 2002; Trcek 2002). However, with the exception of two conserved genes, encoding tRNAIle and tRNAAla, the sequences of 16S-23S rDNA are highly divergent among AAB species. For this reason we analyzed in this study a gene encoding PQQ-dependent ADH as a possible DNA-target. First we confirmed the expression of subunit I of PQQ-dependent ADH (AdhA) also in Asaia, the only genus of AAB which exhibits little or no ADH-activity. Further we analyzed the partial sequences of adhA among some representative species of the genera Acetobacter, Gluconobacter and Gluconacetobacter. The conserved and variable regions in these sequences made possible the construction of A. acetispecific oligonucleotide the specificity of which was confirmed in PCR-reaction using 45 well-defined strains of AAB as DNA-templates. The primer was also successfully used in direct identification of A. aceti from home made cider vinegar as well as for revealing the misclassification of strain IFO 3283 into the species A. aceti. PMID:16261863

Trcek, Janja

2005-10-01

53

Cytenamide trifluoro-acetic acid solvate  

PubMed Central

Cytenamide forms a 1:1 solvate with trifluoro­acetic acid (systematic name: 5H-dibenzo[a,d]cyclo­hepta­triene-5-carboxamide trifluoro­acetic acid solvate), C16H13NO·C2HF3O2. The compound crystallizes with one mol­ecule of cytenamide and one of trifluoro­acetic acid in the asymmetric unit; these are linked by O—H?O and N—H?O hydrogen bonds to form an R 2 2(8) motif. The trifluoro­methyl group of the solvent mol­ecule displays rotational disorder over two sites, with site-occupancy factors of 0.964?(4) and 0.036?(4).

Johnston, Andrea; Florence, Alastair J.; Fabbiani, Francesca J. A.; Shankland, Kenneth; Bedford, Colin T.; Bardin, Julie

2008-01-01

54

Polypyrrole based strong acid catalyst for acetalization  

NASA Astrophysics Data System (ADS)

Novel polypyrrole based acid catalyst has been synthesized through the neutralization reaction of polypyrrole and sulfuric acid. The polypyrrole based acid owned the acidity as high as 6.0 mmol/g, which was much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel solid acid were investigated through the acetalization. The results showed that the novel solid acid held high activities for the reactions. Furthermore, the recycled activities of the catalyst indicated that the solid acid owned high stability during the catalytic process and little acid sites dropped from polypyrrole. The high acidity and stability made the novel polypyrrole based acid hold great potential for the green chemical processes.

Liang, Xuezheng; Cheng, Yuxiao; Qi, Chenze

2011-09-01

55

Heteropolysaccharides from lactic acid bacteria  

Microsoft Academic Search

Microbial exopolysaccharides are biothickeners that can be added to a wide variety of food products, where they serve as viscosifying, stabilizing, emulsifying or gelling agents. Numerous exopolysaccharides with different composition, size and structure are synthesized by lactic acid bacteria. The heteropolysaccharides from both mesophilic and thermophilic lactic acid bacteria have received renewed interest recently. Structural analysis combined with rheological studies

Luc De Vuyst; Bart Degeest

1999-01-01

56

Indole-3-acetic acid in plant-microbe interactions.  

PubMed

Indole-3-acetic acid (IAA) is an important phytohormone with the capacity to control plant development in both beneficial and deleterious ways. The ability to synthesize IAA is an attribute that many bacteria including both plant growth-promoters and phytopathogens possess. There are three main pathways through which IAA is synthesized; the indole-3-pyruvic acid, indole-3-acetamide and indole-3-acetonitrile pathways. This chapter reviews the factors that effect the production of this phytohormone, the role of IAA in bacterial physiology and in plant-microbe interactions including phytostimulation and phytopathogenesis. PMID:24445491

Duca, Daiana; Lorv, Janet; Patten, Cheryl L; Rose, David; Glick, Bernard R

2014-07-01

57

Experimental study of the hydrothermal reactivity of organic acids and acid anions: II. Acetic acid, acetate, and valeric acid  

NASA Astrophysics Data System (ADS)

Organic acids and acid anions occur in substantial concentrations in many aqueous geologic fluids and are thought to take part in a variety of geochemical processes ranging from the transport of metals in ore-forming fluids to the formation of natural gas to serving as a metabolic energy source for microbes in subsurface habitats. The widespread occurrence of organic acids and their potential role in diverse geologic processes has led to numerous experimental studies of their thermal stability, yet there remain substantial gaps in our knowledge of the factors that control the rates and reaction pathways for the decomposition of these compounds under geologic conditions. In order to address some of these uncertainties, a series of laboratory experiments were conducted to examine the behavior of organic acids and acid anions under hydrothermal conditions in the presence of minerals. Reported here are results of experiments where aqueous solutions of acetic acid, sodium acetate, or valeric acid ( n-pentanoic acid) were heated at 325°C, 350 bars in the presence of the mineral assemblages hematite + magnetite + pyrite, pyrite + pyrrhotite + magnetite, and hematite + magnetite. The results indicate that aqueous acetic acid and acetate decompose by a combination of two reaction pathways: decarboxylation and oxidation. Both reactions are promoted by minerals, with hematite catalyzing the oxidation reaction while magnetite catalyzes decarboxylation. The oxidation reaction is much faster, so that oxidation dominates the decomposition of acetic acid and acetate when hematite is present. In contrast to previous reports that acetate decomposed more slowly than acetic acid, we found that acetate decomposed at slightly faster rates than the acid in the presence of minerals. Although longer-chain monocarboxylic acids are generally thought to decompose by decarboxylation, valeric acid appeared to decompose primarily by "deformylation" to 1-butene plus formic acid. Subsequent decomposition of 1-butene and formic acid generated a variety of short-chain (?C 4) hydrocarbons and moncarboxylic acids as well as CO 2. Valeric acid decomposition proceeded more rapidly (by a factor of 2) in the presence of hematite-magnetite-pyrite than with the other mineral assemblages, with the greater reaction rate apparently attributable to the effects of fluid chemistry. Valeric acid was observed to decompose at a substantially faster rate than acetic acid under similar conditions. The results suggest that decomposition of aqueous monocarboxylic acids may make a significant contribution to the conversion of petroleum to light hydrocarbons in natural gas and thermal fluids.

McCollom, Thomas M.; Seewald, Jeffrey S.

2003-10-01

58

Dissimilatory Amino Acid Metabolism in Human Colonic Bacteria  

Microsoft Academic Search

The abilities of slurries of human faecal bacteria to ferment 20 different amino acids were investigated in batch culture incubations. Ammonia, short chain fatty acids, and in some cases, amines, were the principal products of dissimilatory metabolism. The types of SCFA produced were dependent on the chemical compositions of the test substrates. Thus, acetate and butyrate were formed from the

E. A Smith; G. T Macfarlane

1997-01-01

59

Validation of the (GTG)(5)-rep-PCR fingerprinting technique for rapid classification and identification of acetic acid bacteria, with a focus on isolates from Ghanaian fermented cocoa beans.  

PubMed

Amplification of repetitive bacterial DNA elements through the polymerase chain reaction (rep-PCR fingerprinting) using the (GTG)(5) primer, referred to as (GTG)(5)-PCR fingerprinting, was found a promising genotypic tool for rapid and reliable speciation of acetic acid bacteria (AAB). The method was evaluated with 64 AAB reference strains, including 31 type strains, and 132 isolates from Ghanaian, fermented cocoa beans, and was validated with DNA:DNA hybridization data. Most reference strains, except for example all Acetobacter indonesiensis strains and Gluconacetobacter liquefaciens LMG 1509, grouped according to their species designation, indicating the usefulness of this technique for identification to the species level. Moreover, exclusive patterns were obtained for most strains, suggesting that the technique can also be used for characterization below species level or typing of AAB strains. The (GTG)(5)-PCR fingerprinting allowed us to differentiate four major clusters among the fermented cocoa bean isolates, namely A. pasteurianus (cluster I, 100 isolates), A. syzygii- or A. lovaniensis-like (cluster II, 23 isolates), and A. tropicalis-like (clusters III and IV containing 4 and 5 isolates, respectively). A. syzygii-like and A. tropicalis-like strains from cocoa bean fermentations were reported for the first time. Validation of the method and indications for reclassifications of AAB species and existence of new Acetobacter species were obtained through 16S rRNA sequencing analyses and DNA:DNA hybridizations. Reclassifications refer to A. aceti LMG 1531, Ga. xylinus LMG 1518, and Ga. xylinus subsp. sucrofermentans LMG 18788(T). PMID:17920717

De Vuyst, Luc; Camu, Nicholas; De Winter, Tom; Vandemeulebroecke, Katrien; Van de Perre, Vincent; Vancanneyt, Marc; De Vos, Paul; Cleenwerck, Ilse

2008-06-30

60

Acetic acid vapor levels associated with facial prosthetics  

SciTech Connect

The use of Silastic Medical Adhesive Type A in the fabrication of facial prostheses may cause health hazards to the patient and the operator because of acetic acid emissions. Caution must be exercised to remove acetic acid vapors from the air and unliberated acetic acid from material applied directly to the skin.

McElroy, T.H.; Guerra, O.N.; Lee, S.A.

1985-01-01

61

Atmospheric formic and acetic acids: An overview  

NASA Astrophysics Data System (ADS)

Interest in the role of organic acids as chemical constituents in troposphere has been growing rapidly over the past couple of decades. In addition to their presence in the atmosphere in a variety of phases, organic acids are important constituents of the global troposphere and contribute a large fraction (˜25%) to the nonmethane hydrocarbon atmospheric mixture. They contribute significantly to the acidity of precipitation and cloud water, especially in remote regions. In this review, we consider the information presently available on concentration distribution of formic and acetic acids in multiple phases and their sources in different geographical locations, i.e., midlatitude continental, tropical continental and marine sites. Photochemical reactions (i.e., ozone-olefin reaction, isoprene oxidation, gas phase reaction of formaldehyde with HO2, and aqueous phase oxidation of formaldehyde) are important sources of these acids. In midlatitude continental regions, possible sources of formic and acetic acids, in addition to photochemical reactive vehicular emission, are direct emission from vegetation and biomass burning. In tropical continental sites, direct emission from vehicles, ants, soil, vegetation, and biomass burning are the important source of these species. The probable sources at marine locations are photochemical reactions, biogenic emissions, and long-range transport from continental sites.

Khare, Puja; Kumar, N.; Kumari, K. M.; Srivastava, S. S.

1999-05-01

62

Separating acetic acid from furol (furfural) by electrodialysis method  

SciTech Connect

Furfural production by hydrolysis of fibrous plant materials is accompanied by formation of acetic acid in amounts depending on the material used. The amount of acetic formed in the hydrolysis of the fruit shell of oil-tea camellia (Camellia oleosa) (an oilseed-bearing tree) is equal to the amount of furfural. The acetic acid can be separated from the furfural and concentrated to 10% by electrodialysis. A smaller amount of furfural is separated with acetic acid.

Guan, S.F.; Li, C.S. Ye, S.T.; Shen, S.Y.; Wang, Y.T.; Yu, S.H.

1981-01-01

63

Putative ABC Transporter Responsible for Acetic Acid Resistance in Acetobacter aceti  

PubMed Central

Two-dimensional gel electrophoretic analysis of the membrane fraction of Acetobacter aceti revealed the presence of several proteins that were produced in response to acetic acid. A 60-kDa protein, named AatA, which was mostly induced by acetic acid, was prepared; aatA was cloned on the basis of its NH2-terminal amino acid sequence. AatA, consisting of 591 amino acids and containing ATP-binding cassette (ABC) sequences and ABC signature sequences, belonged to the ABC transporter superfamily. The aatA mutation with an insertion of the neomycin resistance gene within the aatA coding region showed reduced resistance to acetic acid, formic acid, propionic acid, and lactic acid, whereas the aatA mutation exerted no effects on resistance to various drugs, growth at low pH (adjusted with HCl), assimilation of acetic acid, or resistance to citric acid. Introduction of plasmid pABC101 containing aatA under the control of the Escherichia coli lac promoter into the aatA mutant restored the defect in acetic acid resistance. In addition, pABC101 conferred acetic acid resistance on E. coli. These findings showed that AatA was a putative ABC transporter conferring acetic acid resistance on the host cell. Southern blot analysis and subsequent nucleotide sequencing predicted the presence of aatA orthologues in a variety of acetic acid bacteria belonging to the genera Acetobacter and Gluconacetobacter. The fermentation with A. aceti containing aatA on a multicopy plasmid resulted in an increase in the final yield of acetic acid.

Nakano, Shigeru; Fukaya, Masahiro; Horinouchi, Sueharu

2006-01-01

64

Temperature effect on acetate and propionate consumption by sulfate-reducing bacteria in saline wastewater.  

PubMed

Seawater toilet flushing, seawater intrusion in the sewerage, and discharge of sulfate-rich industrial effluents elevates sulfate content in wastewater. The application of sulfate-reducing bacteria (SRB) in wastewater treatment is very beneficial; as for example, it improves the pathogen removal and reduces the volume of waste sludge, energy requirement and costs. This paper evaluates the potential to apply biological sulfate reduction using acetate and propionate to saline sewage treatment in moderate climates. Long-term biological sulfate reduction experiments at 10 and 20 °C were conducted in a sequencing batch reactor with synthetic saline domestic wastewater. Subsequently, acetate and propionate (soluble organic carbon) conversion rate were determined in both reactors, in the presence of either or both fatty acids. Both acetate and propionate consumption rates by SRB were 1.9 times lower at 10 °C than at 20 °C. At 10 °C, propionate was incompletely oxidized to acetate. At 10 °C, complete removal of soluble organic carbon requires a significantly increased hydraulic retention time as compared to 20 °C. The results of the study showed that biological sulfate reduction can be a feasible and promising process for saline wastewater treatment in moderate climate. PMID:24463759

van den Brand, T P H; Roest, K; Brdjanovic, D; Chen, G H; van Loosdrecht, M C M

2014-05-01

65

Determination of Indole Acetic Acid by the Salkowsky Reaction  

Microsoft Academic Search

RECENTLY attention has been focused on the reaction of indole acetic acid with ferric ions. Cohen et al.1 have shown that indole acetic acid forms a chelate with iron at acid pH and this has been confirmed by Recaldin and Heath2. The latter state that at pH 2.6 iron slowly decomposes the indole acetic acid in the solution. The oxidation

A. M. Mayer

1958-01-01

66

Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.  

ERIC Educational Resources Information Center

Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

Donahue, Craig J.; Panek, Mary G.

1985-01-01

67

Indole-3-acetic Acid in Douglas Fir  

PubMed Central

We sought evidence for the occurrence and seasonal variation of indole-3-acetic acid (IAA) in shoots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco). Collections obtained in December and June were extracted with methanol and diethyl ether. Extracts were purified by solvent partitioning and with Sephadex LH-20. Qualitative and quantitative information was acquired by gas-liquid chromatography of methyl, trimethylsilyl, or both derivatives of plant extract components. Analysis was performed with polar (XE-60) and moderately polar (Hi-Eff-8-BP) stationary phases. Results from three collections demonstrated that IAA does occur in Douglas fir and that amounts vary seasonally. Mass analysis of the proposed endogenous IAA peak from two representative extracts supported gas-liquid chromatography data and established the presence of IAA in Douglas fir.

Deyoe, David R.; Zaerr, Joe B.

1976-01-01

68

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays  

NASA Technical Reports Server (NTRS)

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

69

Oxidation of Indole-3-Acetic Acid to Oxindole-3-Acetic Acid by an Enzyme Preparation from Zea mays1  

PubMed Central

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, Dennis M.; Bandurski, Robert S.

1988-01-01

70

Recovery of acetic acid from waste streams by extractive distillation.  

PubMed

Wastes have been considered to be a serious worldwide environmental problem in recent years. Because of increasing pollution, these wastes should be treated. However, industrial wastes can contain a number of valuable organic components. Recovery of these components is important economically. Using conventional distillation techniques, the separation of acetic acid and water is both impractical and uneconomical, because it often requires large number of trays and a high reflux ratio. In practice special techniques are used depending on the concentration of acetic acid. Between 30 and 70% (w/w) acetic acid contents, extractive distillation was suggested. Extractive distillation is a multicomponent-rectification method similar in purpose to azeotropic distillation. In extractive distillation, to a binary mixture which is difficult or impossible to separate by ordinary means, a third component termed an entrainer is added which alters the relative volatility of the original constituents, thus permitting the separation. In our department acetic acid is used as a solvent during the obtaining of cobalt(III) acetate from cobalt(II) acetate by an electrochemical method. After the operation, the remaining waste contains acetic acid. In thiswork, acetic acid which has been found in this waste was recovered by extractive distillation. Adiponitrile and sulfolane were used as high boiling solvents and the effects of solvent feed rate/solution feed rate ratio and type were investigated. According to the experimental results, it was seem that the recovery of acetic acid from waste streams is possible by extractive distillation. PMID:12862234

Demiral, H; Yildirim, M Ercengiz

2003-01-01

71

Adverse Effect on Bacteria of Peritoneal Dialysis Solutions that Contain Acetate  

Microsoft Academic Search

Peritoneal dialysis solutions which contained 43 mEq per litre of acetate had a greater antibacterial effect than those containing lactate. Bacteria were isolated from 15 separate clinical infections, each caused by Escherichia coli, Pseudomonas sp., or Staphylo-coccus aureus. Incubation in the dialysate made with acetate substantially reduced the number of viable organisms from all but one of the 45 isolates.

James A. Richardson; Kenneth A. Borchardt

1969-01-01

72

Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures  

Microsoft Academic Search

A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the

E. A. Campanella

2006-01-01

73

Acetic acid production by Dekkera\\/Brettanomyces yeasts  

Microsoft Academic Search

Yeast belonging to the genera Brettanomyces and Dekkera are noted for spoiling cellar and bottled wine through the production of haze, turbidity and acetic acid. However, I was unable to find information on the use of these yeasts for the expressed purpose of acetic acid production. Sixty yeast strains belonging to these, and several other genera, from the ARS Culture

S. N. Freer

2002-01-01

74

Cloud Point Extraction of Acetic Acid from Aqueous Solution  

Microsoft Academic Search

A new acetic acid separation method was developed through a successful combination of cloud point extraction and complex extraction technology (CPE-SE), where an acetic acid complex compound formed and was solubilized in a surfactant micelle solution, instead of an organic solvent, and then concentrated into one phase by a phase separation process of the CPE technology. Since no organic solvent

Bingjia Yao; Li Yang

2009-01-01

75

Asaia bogorensis gen. nov., sp. nov., an unusual acetic acid bacterium in the alpha-Proteobacteria.  

PubMed

Eight Gram-negative, aerobic, rod-shaped and peritrichously flagellated strains were isolated from flowers of the orchid tree (Bauhinia purpurea) and of plumbago (Plumbago auriculata), and from fermented glutinous rice, all collected in Indonesia. The enrichment culture approach for acetic acid bacteria was employed, involving use of sorbitol medium at pH 3.5. All isolates grew well at pH 3.0 and 30 degrees C. They did not oxidize ethanol to acetic acid except for one strain that oxidized ethanol weakly, and 0.35% acetic acid inhibited their growth completely. However, they oxidized acetate and lactate to carbon dioxide and water. The isolates grew well on mannitol agar and on glutamate agar, and assimilated ammonium sulfate for growth on vitamin-free glucose medium. The isolates produced acid from D-glucose, D-fructose, L-sorbose, dulcitol and glycerol. The quinone system was Q-10. DNA base composition ranged from 59.3 to 61.0 mol% G + C. Studies of DNA relatedness showed that the isolates constitute a single species. Phylogenetic analysis based on their 16S rRNA gene sequences indicated that the isolates are located in the acetic acid bacteria lineage, but distant from the genera Acetobacter, Gluconobacter, Acidomonas and Gluconacetobacter. On the basis of the above characteristics, the name Asaia bogorensis gen. nov., sp. nov. is proposed for these isolates. The type strain is isolate 71T (= NRIC 0311T = JCM 10569T). PMID:10758893

Yamada, Y; Katsura, K; Kawasaki, H; Widyastuti, Y; Saono, S; Seki, T; Uchimura, T; Komagata, K

2000-03-01

76

Genetics of Lactic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

77

Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings  

NASA Technical Reports Server (NTRS)

Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

1986-01-01

78

Oxidation of indole-3-acetic acid and oxindole-3-acetic acid to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glucopyranoside in Zea mays seedlings  

NASA Technical Reports Server (NTRS)

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7'-O-beta-D-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid --> Oxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid --> 7-Hydroxyoxindole-3-acetic acid-glucoside.

Nonhebel, H. M.; Bandurski, R. S.

1984-01-01

79

Oxidation of Indole-3-acetic Acid and Oxindole-3-acetic Acid to 2,3-Dihydro-7-hydroxy-2-oxo-1H Indole-3-acetic Acid-7?-O-?-d-Glucopyranoside in Zea mays Seedlings 1  

PubMed Central

Radiolabeled oxindole-3-acetic acid was metabolized by roots, shoots, and caryopses of dark grown Zea mays seedlings to 2,3-dihydro-7-hydroxy-2-oxo-1H indole-3-acetic acid-7?-O-?-d-glycopyranoside with the simpler name of 7-hydroxyoxindole-3-acetic acid-glucoside. This compound was also formed from labeled indole-3-acetic acid supplied to intact seedlings and root segments. The glucoside of 7-hydroxyoxindole-3-acetic acid was also isolated as an endogenous compound in the caryopses and shoots of 4-day-old seedlings. It accumulates to a level of 4.8 nanomoles per plant in the kernel, more than 10 times the amount of oxindole-3-acetic acid. In the shoot it is present at levels comparable to that of oxindole-3-acetic acid and indole-3-acetic acid (62 picomoles per shoot). We conclude that 7-hydroxyoxindole-3-acetic acid-glucoside is a natural metabolite of indole-3-acetic acid in Z. mays seedlings. From the data presented in this paper and in previous work, we propose the following route as the principal catabolic pathway for indole-3-acetic acid in Zea seedlings: Indole-3-acetic acid ? Oxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid ? 7-Hydroxyoxindole-3-acetic acid-glucoside.

Nonhebel, Heather M.; Bandurski, Robert S.

1984-01-01

80

Computerized image analysis for acetic acid induced intraepithelial lesions  

NASA Astrophysics Data System (ADS)

Cervical Intraepithelial Neoplasia (CIN) exhibits certain morphologic features that can be identified during a visual inspection exam. Immature and dysphasic cervical squamous epithelium turns white after application of acetic acid during the exam. The whitening process occurs visually over several minutes and subjectively discriminates between dysphasic and normal tissue. Digital imaging technologies allow us to assist the physician analyzing the acetic acid induced lesions (acetowhite region) in a fully automatic way. This paper reports a study designed to measure multiple parameters of the acetowhitening process from two images captured with a digital colposcope. One image is captured before the acetic acid application, and the other is captured after the acetic acid application. The spatial change of the acetowhitening is extracted using color and texture information in the post acetic acid image; the temporal change is extracted from the intensity and color changes between the post acetic acid and pre acetic acid images with an automatic alignment. The imaging and data analysis system has been evaluated with a total of 99 human subjects and demonstrate its potential to screening underserved women where access to skilled colposcopists is limited.

Li, Wenjing; Ferris, Daron G.; Lieberman, Rich W.

2008-04-01

81

Acetic Acid, the Active Component of Vinegar, Is an Effective Tuberculocidal Disinfectant  

PubMed Central

ABSTRACT Effective and economical mycobactericidal disinfectants are needed to kill both Mycobacterium tuberculosis and non-M. tuberculosis mycobacteria. We found that acetic acid (vinegar) efficiently kills M. tuberculosis after 30 min of exposure to a 6% acetic acid solution. The activity is not due to pH alone, and propionic acid also appears to be bactericidal. M. bolletii and M. massiliense nontuberculous mycobacteria were more resistant, although a 30-min exposure to 10% acetic acid resulted in at least a 6-log10 reduction of viable bacteria. Acetic acid (vinegar) is an effective mycobactericidal disinfectant that should also be active against most other bacteria. These findings are consistent with and extend the results of studies performed in the early and mid-20th century on the disinfectant capacity of organic acids. IMPORTANCE  Mycobacteria are best known for causing tuberculosis and leprosy, but infections with nontuberculous mycobacteria are an increasing problem after surgical or cosmetic procedures or in the lungs of cystic fibrosis and immunosuppressed patients. Killing mycobacteria is important because Mycobacterium tuberculosis strains can be multidrug resistant and therefore potentially fatal biohazards, and environmental mycobacteria must be thoroughly eliminated from surgical implements and respiratory equipment. Currently used mycobactericidal disinfectants can be toxic, unstable, and expensive. We fortuitously found that acetic acid kills mycobacteria and then showed that it is an effective mycobactericidal agent, even against the very resistant, clinically important Mycobacterium abscessus complex. Vinegar has been used for thousands of years as a common disinfectant, and if it can kill mycobacteria, the most disinfectant-resistant bacteria, it may prove to be a broadly effective, economical biocide with potential usefulness in health care settings and laboratories, especially in resource-poor countries.

Cortesia, Claudia; Vilcheze, Catherine; Bernut, Audrey; Contreras, Whendy; Gomez, Keyla; de Waard, Jacobus; Jacobs, William R.; Kremer, Laurent; Takiff, Howard

2014-01-01

82

40 CFR 721.10448 - Acetic acid, hydroxy- methoxy-, methyl ester, reaction products with substituted alkylamine...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Acetic acid, hydroxy- methoxy-, methyl...Substances § 721.10448 Acetic acid, hydroxy- methoxy-, methyl...identified generically as acetic acid, hydroxymethoxy-, methyl...substance according to the average number molecular weight section...

2013-07-01

83

The antibacterial activity and stability of acetic acid.  

PubMed

Acetic acid has been shown to have good antibacterial activity against micro-organisms such as Pseudomonas aeruginosa. This study examined the activity against a range of bacterial pathogens and also assessed any reduction in antibacterial activity due to evaporation or inactivation by organic material in dressings. Acetic acid was active at dilutions as low as 0.166% and the activity was not reduced by evaporation nor by inactivation by cotton swabs. Burn injuries are a major problem in countries with limited resources. Acetic acid is an ideal candidate for use in patients who are treated in those parts of the world. PMID:23747099

Fraise, A P; Wilkinson, M A C; Bradley, C R; Oppenheim, B; Moiemen, N

2013-08-01

84

Ultrasonic Relaxation in Aqueous Acetic Acid Solutions.  

National Technical Information Service (NTIS)

Ultrasonic absorption measurements have been made in aqueous acetic solutions at 15 to 85 MHz using pulse echo and pulse send-receive techniques. A weighted nonlinear regression method has been developed for the computation of the relaxation parameters. A...

L. G. Jackopin E. Yeager

1971-01-01

85

Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.  

PubMed

The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain. PMID:19376463

Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

2009-06-01

86

Phosphatidic Acid Synthesis in Bacteria  

PubMed Central

Membrane phospholipid synthesis is a vital facet of bacterial physiology. Although the spectrum of phospholipid headgroup structures produced by bacteria is large, the key precursor to all of these molecules is phosphatidic acid (PtdOH). Glycerol-3-phosphate derived from the glycolysis via glycerol-phosphate synthase is the universal source for the glycerol backbone of PtdOH. There are two distinct families of enzymes responsible for the acylation of the 1-position of glycerol-3-phosphate. The PlsB acyltransferase was discovered in Escherichia coli, and homologs are present in many eukaryotes. This protein family primarily uses acyl-acyl carrier protein (ACP) endproducts of fatty acid synthesis as acyl donors, but may also use acyl-CoA derived from exogenous fatty acids. The second protein family, PlsY, is more widely distributed in bacteria and utilizes the unique acyl donor, acyl-phosphate, which is produced from acyl-ACP by the enzyme PlsX. The acylation of the 2-position is carried out by members of the PlsC protein family. All PlsCs use acyl-ACP as the acyl donor, although the PlsCs of the ?-proteobacteria also may use acyl-CoA. Phospholipid headgroups are precursors in the biosynthesis of other membrane-associated molecules and the diacylglycerol product of these reactions is converted to PtdOH by one of two distinct families of lipid kinases. The central importance of the de novo and recycling pathways to PtdOH in cell physiology suggest these enzymes are suitable targets for the development of antibacterial therapeutics in Gram-positive pathogens. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.

Yao, Jiangwei; Rock, Charles O.

2012-01-01

87

Molecular Analysis of Arsenate-Reducing Bacteria within Cambodian Sediments following Amendment with Acetate? ‡  

PubMed Central

The health of millions is threatened by the use of groundwater contaminated with sediment-derived arsenic for drinking water and irrigation purposes in Southeast Asia. The microbial reduction of sorbed As(V) to the potentially more mobile As(III) has been implicated in release of arsenic into groundwater, but to date there have been few studies of the microorganisms that can mediate this transformation in aquifers. With the use of stable isotope probing of nucleic acids, we present evidence that the introduction of a proxy for organic matter (13C-labeled acetate) stimulated As(V) reduction in sediments collected from a Cambodian aquifer that hosts arsenic-rich groundwater. This was accompanied by an increase in the proportion of prokaryotes closely related to the dissimilatory As(V)-reducing bacteria Sulfurospirillum strain NP-4 and Desulfotomaculum auripigmentum. As(V) respiratory reductase genes (arrA) closely associated with those found in Sulfurospirillum barnesii and Geobacter uraniumreducens were also detected in active bacterial communities utilizing 13C-labeled acetate in microcosms. This study suggests a direct link between inputs of organic matter and the increased prevalence and activity of organisms which transform As(V) to the potentially more mobile and thus hazardous As(III) via dissimilatory As(V) reduction.

Lear, G.; Song, B.; Gault, A. G.; Polya, D. A.; Lloyd, J. R.

2007-01-01

88

Conversion of acetic acid to methane by thermophiles: Progress report.  

National Technical Information Service (NTIS)

The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isola...

S. Zinder

1991-01-01

89

SOLVENT EXTRACTION OF WASTEWATERS FROM ACETIC-ACID MANUFACTURE  

EPA Science Inventory

Solvent extraction was evaluated as a potential treatment method for wastewaters generated during the manufacture of acetic acid. Possible goals for an extraction process were considered. For the wastewater samples studied, extraction appeared to be too expensive to be practical ...

90

Hydrothermal production of formic and acetic acids from syringol  

Microsoft Academic Search

The production of formic and acetic acids (or salts) by hydrothermal oxidation of syringol, a model compound for lignin, was\\u000a investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6%\\u000a and 11.3% at the reaction condition of 0.5 mol\\/L NaOH, 120% H2O2 supply and 280 °C. These results will inform studies

Lu-ting Pan; Zheng Shen; Lei Wu; Ya-lei Zhang; Xue-fei Zhou; Fang-ming Jin

2010-01-01

91

Inhibition of citrus fungal pathogens by using lactic acid bacteria.  

PubMed

The effect of lactic acid bacteria (LAB) on pathogenic fungi was evaluated and the metabolites involved in the antifungal effect were characterized. Penicillium digitatum (INTA 1 to INTA 7) and Geotrichum citri-aurantii (INTA 8) isolated from decayed lemon from commercial packinghouses were treated with imazalil and guazatine to obtain strains resistant to these fungicides. The most resistant strains (4 fungal strains) were selected for evaluating the antifungal activity of 33 LAB strains, among which only 8 strains gave positive results. The antifungal activity of these LAB strains was related to the production of lactic acid, acetic acid, and phenyllactic acid (PLA). A central composite design and the response surface methodology were used to evaluate the inhibitory effect of the organic acids produced by the LAB cultures. The antifungal activity of lactic acid was directly related to its concentration; however, acetic acid and PLA showed a peak of activity at 52.5 and 0.8 mM, respectively, with inhibition rates similar to those obtained with Serenade((R)) (3.0 ppm) imazalil (50 ppm) and guazatine (50 ppm). Beyond the peak of activity, a reduction in effectiveness of both acetic acid and PLA was observed. Comparing the inhibition rate of the organic acids, PLA was about 66- and 600-fold more effective than acetic acid and lactic acid, respectively. This study presents evidences on the antifungal effect of selected LAB strains and their end products. Studies are currently being undertaken to evaluate the effectiveness in preventing postharvest diseases on citrus fruits. PMID:20722936

Gerez, C L; Carbajo, M S; Rollán, G; Torres Leal, G; Font de Valdez, G

2010-08-01

92

Lactic Acid Bacteria in the Gut  

Microsoft Academic Search

From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped, gram-positive, polyphyletic bacteria. The vast majority of the LAB belong to the phylum

M. Stolaki; Vos de W. M; M. Kleerebezem; E. G. Zoetendal

2012-01-01

93

Energy transduction in lactic acid bacteria  

Microsoft Academic Search

In the discovery of some general principles of energy transduction, lactic acid bacteria have played an important role. In this review, the energy transducing processes of lactic acid bacteria are discussed with the emphasis on the major developments of the past 5 years. This work not only includes the biochemistry of the enzymes and the bioenergetics of the processes, but

Bert Poolman

1993-01-01

94

Proteolytic systems in lactic acid bacteria  

Microsoft Academic Search

The proteolytic systems of lactic acid bacteria are important as a means of making protein and peptide N available for growth and as part of the curing or maturation processes which give foods their characteristic rheological and organoleptic properties. The proteolytic systems of lactic acid bacteria are described in relation to their growth and their functions in protein-rich foods. Their

Barry A. Law; Jens Kolstad; Pekka Varmanen; Bert Poolman I; Wil N. Konings

1983-01-01

95

Tetrazole acetic acid: tautomers, conformers, and isomerization.  

PubMed

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol(-1) energy range and should be appreciably populated at the sublimation temperature (?330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol(-1)) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol(-1)). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm(-1), where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm(-1), transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed. PMID:24527914

Araujo-Andrade, C; Reva, I; Fausto, R

2014-02-14

96

Tetrazole acetic acid: Tautomers, conformers, and isomerization  

NASA Astrophysics Data System (ADS)

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol-1 energy range and should be appreciably populated at the sublimation temperature (˜330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol-1) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol-1). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm-1, where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm-1, transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed.

Araujo-Andrade, C.; Reva, I.; Fausto, R.

2014-02-01

97

Antagonism between osmophilic lactic Acid bacteria and yeasts in brine fermentation of soy sauce.  

PubMed

Brine fermentation by osmophilic lactic acid bacteria and yeasts for long periods of time is essential to produce a good quality of shoyu (Japanese fermented soy sauce). It is well known that lactic acid fermentation by osmophilic lactic acid bacteria results in the depression of alcoholic fermentation by osmophilic yeasts, but the nature of the interaction between osmophilic lactic acid bacteria and yeasts in brine fermentation of shoyu has not been revealed. The inhibitory effect of osmophilic lactic acid bacteria on the growth of osmophilic yeasts was investigated. It was recognized that osmophilic shoyu yeasts such as Saccharomyces rouxii and Torulopsis versatilis were inhibited by a metabolite produced by osmophilic lactic acid bacteria (belonging to Pediococcus halophilus) in brine fermentation of shoyu. The primary inhibitor was considered to be acetic acid, although lactic acid was slightly inhibitory. PMID:16345625

Noda, F; Hayashi, K; Mizunuma, T

1980-09-01

98

Liquid-liquid equilibria of the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorene (3,5,5-trimethyl-2-cyclohexen-1-one)  

SciTech Connect

Liquid-liquid equilibria for the ternary systems water + acetic acid + ethyl acetate and water + acetic acid + isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) were measured over the temperature range (283 to 313) K. The results were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models; experimental data were successfully reproduced. The UNIQUAC model was the most accurate in correlating the overall equilibrium composition of the studied systems. Also the NRTL model satisfactorily predicted the equilibrium composition. Isophorone experimentally resulted in a better extraction capacity for acetic acid and in a lower miscibility with water.

Colombo, A.; Battilana, P.; Ragaini, V.; Bianchi, C.L. [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry] [Milan Univ. (Italy). Dept. of Physical Chemistry and Electrochemistry; Carvoli, G. [Chemial S.p.A., Cavaglia (Italy)] [Chemial S.p.A., Cavaglia (Italy)

1999-01-01

99

Catalysis of the Carbonylation of Alcohols to Carboxylic Acids Including Acetic Acid Synthesis from Methanol.  

ERIC Educational Resources Information Center

Monsanto's highly successful synthesis of acetic acid from methanol and carbon monoxide illustrates use of new starting materials to replace pretroleum-derived ethylene. Outlines the fundamental aspects of the acetic acid process and suggests ways of extending the synthesis to higher carboxylic acids. (JN)

Forster, Denis; DeKleva, Thomas W.

1986-01-01

100

Stress responses in lactic acid bacteria  

Microsoft Academic Search

Lactic acid bacteria (LAB) constitute a heterogeneous group of bacteria that are traditionally used to produce fermented foods. The industrialization of food bio-transformations increased the economical importance of LAB, as they play a crucial role in the development of the organoleptique and hygienic quality of fermented products. Therefore, the reliability of starter strains in terms of quality and functional properties

Maarten van de Guchte; Pascale Serror; Christian Chervaux; Tamara Smokvina; Stanislav D. Ehrlich; Emmanuelle Maguin

2002-01-01

101

CARCINOGENICITY OF THE CHLORINATED ACETIC ACIDS  

EPA Science Inventory

Dichloroacetic Acid (DCAA) and trichloroacetic acid (TCAA) comprise a major fraction of the reaction products formed when water containing a variety of precursor humic materials is chlorinated. Both DCAA and TCAA administered in the drinking water increased the incidence of hepat...

102

Biosynthesis of myristic acid in luminescent bacteria. [Vibrio harveyi  

SciTech Connect

In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with (/sup 14/C) acetate in a nutrient-depleted medium accumulated substantial tree (/sup 14/C)fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with (/sup 14/C)acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition.

Byers, D.M.

1987-05-01

103

21 CFR 184.1005 - Acetic acid.  

Code of Federal Regulations, 2013 CFR

...64-19-7) is known as ethanoic acid. It occurs naturally in plant and animal tissues. It is produced by fermentation of...170.3(n)(24) of this chapter; 0.6 percent for meat products as defined in § 170.3(n)(29) of this...

2013-04-01

104

Acidophilic, Heterotrophic Bacteria of Acidic Mine Waters  

PubMed Central

Obligately acidophilic, heterotrophic bacteria were isolated both from enrichment cultures developed with acidic mine water and from natural mine drainage. The bacteria were grouped by the ability to utilize a number of organic acids as sole carbon sources. None of the strains were capable of chemolithotrophic growth on inorganic reduced iron and sulfur compounds. All bacteria were rod shaped, gram negative, nonencapsulated, motile, capable of growth at pH 2.6 but not at pH 6.0, catalase and oxidase positive, strictly aerobic, and capable of growth on citric acid. The bacteria were cultivatable on solid nutrient media only if agarose was employed as the hardening agent. Bacterial densities in natural mine waters ranged from approximately 20 to 250 cells per ml, depending upon source and culture medium. Ferric hydrates and stream vegetation contained from 1,500 to over 7 × 106 cells per g. Images

Wichlacz, Paul L.; Unz, Richard F.

1981-01-01

105

The impact of acetate metabolism on yeast fermentative performance and wine quality: reduction of volatile acidity of grape musts and wines.  

PubMed

Acetic acid is the main component of the volatile acidity of grape musts and wines. It can be formed as a by-product of alcoholic fermentation or as a product of the metabolism of acetic and lactic acid bacteria, which can metabolize residual sugars to increase volatile acidity. Acetic acid has a negative impact on yeast fermentative performance and affects the quality of certain types of wine when present above a given concentration. In this mini-review, we present an overview of fermentation conditions and grape-must composition favoring acetic acid formation, as well the metabolic pathways leading to its formation and degradation by yeast. The negative effect of acetic acid on the fermentative performance of Saccharomyces cerevisiae will also be covered, including its role as a physiological inducer of apoptosis. Finally, currently available wine deacidification processes and new proposed solutions based on zymological deacidification by select S. cerevisiae strains will be discussed. PMID:20931186

Vilela-Moura, Alice; Schuller, Dorit; Mendes-Faia, Arlete; Silva, Rui D; Chaves, Susana R; Sousa, Maria João; Côrte-Real, Manuela

2011-01-01

106

Acetic acid: Microwave spectra, internal rotation and substitution structure  

Microsoft Academic Search

The internal rotation splittings in the microwave spectrum of acetic acid have been re-examined, using both principal axis method (PAM) and internal axis method (IAM) treatments. It is shown how individual terms in the PAM equation can be correlated to the first terms in an expansion of the corresponding IAM formula. When centrifugal distortion was allowed for, both methods reproduced

B. P. van Eijck; J. van Opheusden; M. M. M. van Schaik; E. van Zoeren

1981-01-01

107

Mass Spectral and Electric Deflection Study of Acetic Acid Clusters.  

National Technical Information Service (NTIS)

Acetic acid clusters, (CH3COOH)n, up to n = 10, were produced in a supersonic beam expansion and analyzed in a molecular beam quadrupole mass spectrometer. A general mechanism for their mass spectral fragmentation was deduced. Polarity of the first four c...

R. Sivert I. Cadez J. Van Doren A. W. Castleman

1984-01-01

108

Occurrence and metabolism of 7-hydroxy-2-indolinone-3-acetic acid in Zea mays  

NASA Technical Reports Server (NTRS)

7-Hydroxy-2-indolinone-3-acetic acid was identified as a catabolite of indole-3-acetic acid in germinating kernels of Zea mays and found to be present in amounts of ca 3.1 nmol/kernel. 7-Hydroxy-2-indolinone-3-acetic acid was shown to be a biosynthetic intermediate between 2-indolinone-3-acetic acid and 7-hydroxy-2-indolinone-3-acetic acid-7'-O-glucoside in both kernels and roots of Zea mays. Further metabolism of 7-hydroxy-2-[5-3H]-indolinone-3-acetic acid-7'-O-glucoside occurred to yield tritiated water plus, as yet, uncharacterized products.

Lewer, P.; Bandurski, R. S.

1987-01-01

109

3-Acet-oxy-2-naphthoic acid.  

PubMed

In the title compound, C(13)H(10)O(4), an analog of acetyl-salicylic acid, the naphthalene unit is twisted slightly due to ortho disubstitution [dihedral angle between conjugated rings system in the naphthalene unit = 2.0?(2)°]. The mean planes of the carb-oxy-lic and ester groups are almost coplanar and perpendicular, respectively, to the mean plane of the conjugated aromatic system, making dihedral angles of 8.9?(3) and 89.3?(1)°. In the crystal, mol-ecules are paired through their carb-oxy-lic groups by the typical centrosymmetric O-H?O inter-actions with R(2) (2)(8) hydrogen-bond motifs. In addition, several weak C-H?O inter-molecular contacts are also observed. Finally, the mol-ecules are stacked along crystallographic [100] and [010] directions. PMID:21589033

Souza, Bruno S; Vitto, Ramon; Nome, Faruk; Kirby, Anthony J; Bortoluzzi, Adailton J

2010-01-01

110

[Conversion of acetic acid to methane by thermophiles  

SciTech Connect

The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

Zinder, S.H.

1993-01-01

111

Review: Bacteriocins of Lactic Acid Bacteria  

Microsoft Academic Search

During the last few years, a large number of new bacteriocins produced by lactic acid bacteria (LAB) have been identified and characterized. LAB-bacteriocins comprise a heterogeneous group of physicochemically diverse ribosomally-synthesized peptides or proteins showing a narrow or broad antimicrobial activity spectrum against Gram-positive bacteria. Bacteriocins are classified into separate groups such as the lantibiotics (Class I); the small (<10

L. M. Cintas; M. P. Casaus; C. Herranz; I. F. Nes; P. E. Hernández

2001-01-01

112

Acetic Acid Bacterial Biota of the Pink Sugar Cane Mealybug, Saccharococcus sacchari, and Its Environs  

PubMed Central

Saccharococcus sacchari is the primary colonizer of the developing “sterile” tissue between the leaf sheath and stem of sugar cane. The honeydew secreted by the mealybugs is acidic (about pH 3) and supports an atypical epiphytic microbiota dominated by acetobacter-like bacteria and acidophilic yeast species. However, Erwinia and Leuconostoc species predominate within the leaf sheath pocket region when the mealybugs die out. The unidentified acetobacters were readily isolated from S. sacchari throughout its life cycle and from other genera of mealybugs on sugar cane and various other plants, both above and below ground. No other insect present on sugar cane was a significant vector of acetic acid bacteria. The major factors restricting microbial diversity within the environs of mealybugs were considered to be yeast activity along with bacterial production of acetic acid, ketogluconic acids, and gamma-pyrones, in association with their lowering of pH. The microbial products may aid in suppressing the attack by the parasitic mold Aspergillus parasiticus on mealybugs but could act as attractants for the predatory fruit fly Cacoxenus perspicax.

Ashbolt, Nicholas J.; Inkerman, Peter A.

1990-01-01

113

Toughening of poly(lactic acid) by ethylene- co-vinyl acetate copolymer with different vinyl acetate contents  

Microsoft Academic Search

The well-known bio-based and biocompostable poly(lactic acid), PLA, suffers from brittleness and a low heat distortion temperature. In this paper, we address a possible route to make PLA tough(er) by blending with ethylene-co-vinyl acetate (EVA) with different vinyl acetate contents. The compatibility and phase morphology of the PLA\\/EVA blends was controlled by the ratio of vinyl acetate and ethylene in

P. Ma; D. G. Hristova-Bogaerds; J. G. P. Goossens; Y. Zhang; P. J. Lemstra

2012-01-01

114

First insights into the syntrophic acetate-oxidizing bacteria - a genetic study  

PubMed Central

Syntrophic acetate-oxidizing bacteria have been identified as key organisms for efficient biogas production from protein-rich materials. They normally grow as lithotrophs or heterotrophs, producing acetate through the Wood–Ljungdahl pathway, but when growing in syntrophy with methanogens, they reportedly reverse this pathway and oxidize acetate to hydrogen and carbon dioxide. However, the biochemical and regulatory mechanisms behind the shift and the way in which the bacteria regain energy remain unknown. In a genome-walking approach, starting with degenerated primers, we identified those gene clusters in Syntrophaceticus schinkii, Clostridium ultunense, and Tepidanaerobacter acetatoxydans that comprise the formyltetrahydrofolate synthetase gene (fhs), encoding a key enzyme of the Wood–Ljungdahl pathway. We also discovered that the latter two harbor two fhs alleles. The fhs genes are phylogenetically separated and in the case of S. schinkii functionally linked to sulfate reducers. The T. acetatoxydans fhs1 cluster combines features of acetogens, sulfate reducers, and carbon monoxide oxidizers and is organized as a putative operon. The T. acetatoxydans fhs2 cluster encodes Wood–Ljungdahl pathway enzymes, which are also known to be involved in C1 carbon metabolism. Isolation of the enzymes illustrated that both formyltetrahydrofolate synthetases of T. acetatoxydans were functionally active. However, only fhs1 was expressed, confirming bidirectional usage of the pathway.

Muller, Bettina; Sun, Li; Schnurer, Anna

2013-01-01

115

Structured catalysts for photo-Fenton oxidation of acetic acid  

Microsoft Academic Search

In this work photo-Fenton oxidation of acetic acid, was carried out on perovskites based structured catalysts, in the presence or in the absence of low amounts of Pt. Homogeneous photo-Fenton reaction by ferrioxalate complex has been also performed. The comparison of homogeneous and heterogeneous photo-Fenton oxidation indicates that the use of a heterogeneous structured catalyst greatly improves the total organic

Diana Sannino; Vincenzo Vaiano; Paolo Ciambelli; Lyubov A. Isupova

2011-01-01

116

Adaptive cytoprotection against acetic acid induced colonic injury in rats  

Microsoft Academic Search

Background and aims: The phenomenon of prostaglandin dependent adaptive cytoprotection has been well established in the stomach and duodenum but not in the colon. This study investigated whether it also occurs in the colon. Methods: Fisher rats received intracolonic administration (0.5 ml) of saline or acetic acid at low concentrations (0.01-5%) followed by high concentration (25%) at various intervals (10-720

Toru Kono; Masashi Yoneda; Kei Ohara; Tokiyoshi Ayabe; Naoyuki Chisato; Yutaka Kohgo; Shinichi Kasai; Akira Terano; Yvette Taché

2001-01-01

117

Potential energy surfaces for proton abstractions from acetic acid  

Microsoft Academic Search

The abstractions of hydrogen from both carbon and oxygen in acetic acid by hydride, fluoride, and hydroxide anions have been studied using ab initio electronic structure calculations. Molecular structures were optimized at the Hartree-Fock level of theory using the 6-31++G(d,p) basis set. For energetics, the 6-311++G(d,p) basis set was used, with second- and fourth-order perturbation theory corrections, for both minima

Mark S. Gordon; David R. Gano; Eugene Curtiss

1996-01-01

118

Photocatalytic oxidation and decomposition of acetic acid on titanium silicalite.  

PubMed

Transient reaction of adsorbed monolayers of acetic acid was used to characterize the photocatalytic properties of titanium silicalite zeolites (TS-1). The TS-1 zeolites having Si/Ti ratios of 5, 12.5, and 50 are effective catalysts at room temperature for both photocatalytic oxidation (PCO) and decomposition (PCD) of acetic acid. The rates of PCO are higher than the rates of PCD for each catalyst. Acetic acid oxidized photocatalytically in 0.2% O2 to form gas-phase CO2 and CH4 and adsorbed H2O on the TS-1 catalysts, whereas no CH4 formed on Degussa P25 TiO2. Isotope labeling showed that, on both TiO2 and TS-1 catalysts, the alpha-carbon formed CO2 whereas the beta-carbon formed CH4 and CO2. The rates of oxidation of the two carbons have different dependencies on UV intensity. The catalysts with higher Si/Ti ratios adsorbed significantly more acetic acid, and the PCO rates per gram of titanium are highest on the TS-1 catalyst with the lowest Ti content, apparently because a larger fraction of the Ti atoms are surface atoms on this catalyst. During PCD in an inert atmosphere, CO2, CH4, and C2H6 formed on TiO2 and on the catalyst with a Si/Ti ratio of 5, but C2H6 was not detected on the other catalysts. The CO2/CH4 selectivity during PCD increased with increasing Si/Ti ratio. The first step in PCO and PCD on TS-1 catalysts appears to be similar and involves formation of a CH3 radical. PMID:11347941

Lee, G D; Tuan, V A; Falconer, J L

2001-03-15

119

40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Acetic acid, [(5-chloro-8-quinolinyl...Specific Chemical Substances § 721.304 Acetic acid, [(5-chloro-8-quinolinyl...The chemical substance identified as acetic acid,...

2010-07-01

120

40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Acetic acid, [(5-chloro-8-quinolinyl...Specific Chemical Substances § 721.304 Acetic acid, [(5-chloro-8-quinolinyl...The chemical substance identified as acetic acid,...

2009-07-01

121

Probiotic Spectra of Lactic Acid Bacteria (LAB)  

Microsoft Academic Search

Lactic acid bacteria (LAB) and their probio-active cellular substances exert many beneficial effects in the gastrointestinal tract. LAB prevent adherence, establishment, and replication of several enteric mucosal pathogens through several antimicrobial mechanisms. LAB also release various enzymes into the intestinal lumen and exert potential synergistic effects on digestion and alleviate symptoms of intestinal malabsoption. Consumption of LAB fermented dairy products

A. S. Naidu; W. R. Bidlack; R. A. Clemens

1999-01-01

122

The proteotytic systems of lactic acid bacteria  

Microsoft Academic Search

Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The proteolytic system consists of an extracellularly located serine-proteinase, transport systems specific for di-tripeptides and oligopeptides (> 3

Edmund R. S. Kunji; Igor Mierau; Anja Hagting; Bert Poolman; Wil N. Konings

1996-01-01

123

Lactic acid bacteria in fish: a review  

Microsoft Academic Search

Fish are continuously exposed to a wide range of microorganisms present in the environment, and the microbiota of fish have been the subject of several reviews. This review evaluates lactic acid bacteria in fish, and focuses on the several investigations that have demonstrated that Streptococcus, Leuconostoc, Lactobacillus, and Carnobacterium belong to the normal microbiota of the gastrointestinal tract in healthy

Einar Ringø; François-Joël Gatesoupe

1998-01-01

124

Production of Menaquinones by Lactic Acid Bacteria  

Microsoft Academic Search

Lactic acid bacteria were examined for their ability to produce quinone compounds, which may include dietary sources of menaquinones. Isoprenyl quinones in bacterial cells grown in a synthetic medium were extracted and analyzed by thin layer chromatography. Lactococcus lactis ssp. cremoris (three strains), Lacto- coccus lactis ssp. lactis (two strains), and Leuconostoc lactis were selected as high producers of quinone

Takashi Morishita; Natsuko Tamura; Takashi Makino; Satoshi Kudo

1999-01-01

125

Production of conjugated fatty acids by lactic acid bacteria.  

PubMed

Conjugated fatty acids have attracted much attention as a novel type of biologically beneficial functional lipid. Some isomers of conjugated linoleic acid (CLA) reduce carcinogenesis, atherosclerosis, and body fat. Considering the use of CLA for medicinal and nutraceutical purposes, a safe isomer-selective process is required. The introduction of biological reactions for CLA production could be an answer. We screened microbial reactions useful for CLA production, and found several unique reactions in lactic acid bacteria. Lactic acid bacteria produced CLA from linoleic acid. The produced CLA comprised a mixture of cis-9,trans-11-octadecadienoic acid (18:2) and trans-9,trans-11-18:2. Lactobacillus plantarum AKU 1009a was selected as a potential CLA producer. Using washed cells of L. plantarum AKU 1009a as a catalyst, CLA production from linoleic acid reached 40 mg/ml under the optimized conditions. The CLA-producing reaction was found to consist of two successive reactions, i.e., hydration of linoleic acid to 10-hydroxy-12-octadecenoic acid and dehydrating isomerization of the hydroxy fatty acid to CLA. On the basis of these results, the transformation of hydroxy fatty acids by lactic acid bacteria was investigated. Lactic acid bacteria transformed ricinoleic acid (12-hydroxy-cis-9-octadecenoic acid) to CLA (a mixture of cis-9,trans-11-18:2 and trans-9,trans-11-18:2). Castor oil, which is rich in the triacylglycerol form of ricinoleic acid, was also found to act as a substrate for CLA production by lactic acid bacteria with the aid of lipase-catalyzed triacylglycerol hydrolysis. L. plantarum AKU 1009a produced conjugated trienoic fatty acids from alpha- and gamma-linolenic acid. The trienoic fatty acids produced from alpha-linolenic acid were identified as cis-9,trans-11,cis-15-octadecatrienoic acid (18:3) and trans-9,trans-11,cis-15-18:3. Those produced from gamma-linolenic were cis-6,cis-9,trans-11-18:3 and cis-6,trans-9,trans-11-18:3. The conjugated trienoic fatty acids produced from alpha- and gamma-linolenic acid were further saturated by L. plantarum AKU 1009a to trans-10,cis-15-18:2 and cis-6,trans-10-18:2, respectively. PMID:16310724

Ogawa, Jun; Kishino, Shigenobu; Ando, Akinori; Sugimoto, Satoshi; Mihara, Kousuke; Shimizu, Sakayu

2005-10-01

126

The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses  

PubMed Central

Aim Sodium acetate (NaAcetate) has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA) administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1) 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial); or 2) a hay/grain meal alone (Control trial). Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse.

Waller, Amanda; Lindinger, Michael I

2007-01-01

127

Production of acetic acid from methanol by thermophilic Methanosarcina sp.: Acetate production as an index in abnormal methane fermentation  

Microsoft Academic Search

Production of approximately 80–160 ?mol of acetic acid was observed in 1% (w\\/w) methanol culture media (10 ml) of thermophilic Methanosarcina sp. from which essential nutrients such as salts of NH4+, PO43?, K+, Ca2+ and Mg2+ were removed. Similar acetic acid production was found when methane gas formation was controlled to approximately 50% by means of inhibitors of methyl group

Makoto Yamaguchi; Kiyoshi Minami

1998-01-01

128

Ultrafine cellulose fibers produced by Asaia bogorensis, an acetic acid bacterium.  

PubMed

The ability to synthesize cellulose by Asaia bogorensis, a member of the acetic acid bacteria, was studied in two substrains, AJ and JCM. Although both strains have identical 16S rDNA sequence, only the AJ strain formed a solid pellicle at the air-liquid interface in static culture medium, and we analyzed this pellicle using a variety of techniques. In the presence of cellulase, glucose and cellobiose were released from the pellicle suggesting that it is made of cellulose. Field emission electron microscopy allowed the visualization of a 3D knitted structure with ultrafine microfibrils (approximately 5-20 nm in width) in cellulose from A. bogorensis compared with the 40-100 nm wide microfibrils observed in cellulose isolated from Gluconacetobacter xylinus, suggesting differences in the mechanism of cellulose biosynthesis or organization of cellulose synthesizing sites in these two related bacterial species. Identifying these differences will lead to a better understanding of cellulose biosynthesis in bacteria. PMID:21650167

Kumagai, Akio; Mizuno, Masahiro; Kato, Naoto; Nozaki, Kouichi; Togawa, Eiji; Yamanaka, Shigeru; Okuda, Kazuo; Saxena, Inder M; Amano, Yoshihiko

2011-07-11

129

Peptidases and amino acid catabolism in lactic acid bacteria  

Microsoft Academic Search

The conversion of peptides to free amino acids and their subsequent utilization is a central metabolic activity in prokaryotes. At least 16 peptidases from lactic acid bacteria (LAB) have been characterized biochemically and\\/or genetically. Among LAB, the peptidase systems of Lactobacillus helveticus and Lactococcus lactis have been examined in greatest detail. While there are homologous enzymes common to both systems,

Jeffrey E. Christensen; Edward G. Dudley; Jeffrey A. Pederson; James L. Steele

1999-01-01

130

Formation of biologically relevant carboxylic acids during the gamma irradiation of acetic acid  

NASA Technical Reports Server (NTRS)

Irradiation of aqueous solutions of acetic acid with gamma rays produced several carboxylic acids in small yield. Their identification was based on the technique of gas chromatography combined with mass spectrometry. Some of these acids are Krebs Cycle intermediates. Their simultaneous formation in experiments simulating the primitive conditions on the earth suggests that metabolic pathways may have had their origin in prebiotic chemical processes.

Negron-Mendoza, A.; Ponnamperuma, C.

1976-01-01

131

Production of Formic Acid and Acetic Acid by Hydrothermal Oxidation of Alkali Lignin  

NASA Astrophysics Data System (ADS)

The production of formic acid and acetic acid by hydrothermal oxidation of alkali lignin, a kind of biomasses, was investigated using a batch reactor with H2O2 oxidant. Experiments were performed over a wide range of conditions with temperature varying from 260 to 320° C, oxygen supply varying from 60% to 120%, and reaction time varying from 30 to 150 s. The highest yield of formic acid was 4.9% at 280° C for 120 s with the additive ratio of H2O2 100%. The highest value of acetic acid was 12.3% at 300° C for 120 s with the additive ratio of H2O2 100%. Based on the intermediate products identified by GC/MS and HPLC, reaction pathways of alkali lignin are discussed. It was found that maleic acid and fumaric acid were two primary unsaturated intermediate products. The production of formic acid and acetic acid were come from the oxidative decomposition of intermediate products in the oxidation process. Increasing the formation of saturated dicarboxylic acids and glutaconic acid would enhance the acetic acid yield.

Zeng, Xu; Jin, Fangming; Cao, Jianglin; Yin, Guodong; Zhang, Yalei; Zhao, Jianfu

2010-11-01

132

Kinetic Modeling of Esterification of Ethylene Glycol with Acetic Acid  

NASA Astrophysics Data System (ADS)

The reaction kinetics of the esterification of ethylene glycol with acetic acid in the presence of cation exchange resin has been studied and kinetic models based on empirical and Langmuir approach has been developed. The Langmuir based model involving eight kinetic parameters fits experimental data much better compared to empirical model involving four kinetic parameters. The effect of temperature and catalyst loading on the reaction system has been analyzed. Further, the activation energy and frequency factor of the rate constants for Langmuir based model has been estimated.

Yadav, Vishnu P.; Mukherjee, Rudra Palash; Bantraj, Kandi; Maity, Sunil K.

2010-10-01

133

Indole 3-acetic acid production by ectomycorrhizal fungi.  

PubMed

Ability of 8 ectomycorrhizal fungi to synthesise indole 3-acetic acid from L-tryptophan and their growth rate were studied. Differences in the levels of IAA synthesis and biomass production among the 8 mycorrhizal fungi were observed. A positive correlation was recorded between IAA level and mycelial growth. The synthesis of IAA and mycelial biomass were maximum on 30th day after incubation. Pisolithus tinctorius and Laccaria laccata exhibited higher amounts of IAA production than other fungi, whereas Amanita muscaria and Rhizopogon luteolus showed least quantity of IAA. PMID:1521864

Gopinathan, S; Raman, N

1992-02-01

134

Pediocin production by recombinant lactic acid bacteria  

Microsoft Academic Search

Production of the anti-listerial bacteriocin, pediocin, by lactic acid bacteria (LAB) transformed with the cloning vector pPC418 (Ped+, 9.1 kb) was influenced by composition of media and incubation temperature. Maximum pediocin production, tested against Listeria innocua, by electrotransformants of Lactococcus lactis ssp. lactis was measured in tryptone\\/lactose\\/yeast extract medium after 24 h growth at 30 °C, while incubation at 40 °C was optimum for

G. A. Somkuti; D. H. Steinberg

2003-01-01

135

High efficiency recombineering in lactic acid bacteria  

PubMed Central

The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to Gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lactic acid bacteria. Mutations were incorporated in the chromosome of Lactobacillus reuteri and Lactococcus lactis without selection at frequencies ranging between 0.4% and 19%. Whole genome sequence analysis showed that ssDNA recombineering is specific and not hypermutagenic. To highlight the utility of ssDNA recombineering we reduced the intrinsic vancomymycin resistance of L. reuteri >100-fold. By creating a single amino acid change in the d-Ala-d-Ala ligase enzyme we reduced the minimum inhibitory concentration for vancomycin from >256 to 1.5?µg/ml, well below the clinically relevant minimum inhibitory concentration. Recombineering thus allows high efficiency mutagenesis in lactobacilli and lactococci, and may be used to further enhance beneficial properties and safety of strains used in medicine and industry. We expect that this work will serve as a blueprint for the adaptation of ssDNA recombineering to other Gram-positive bacteria.

van Pijkeren, Jan-Peter; Britton, Robert A.

2012-01-01

136

Clostridium strain which produces acetic acid from waste gases  

DOEpatents

A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 4 figs.

Gaddy, J.L.

1997-01-14

137

Lactic acid bacteria of meat and meat products  

Microsoft Academic Search

When the growth of aerobic spoilage bacteria is inhibited, lactic acid bacteria may become the dominant component of the microbial flora of meats. This occurs with cured meats and with meats packaged in films of low gas permeability. The presence of a flora of psychrotrophic lactic acid bacteria on vacuum-packaged fresh chilled meats usually ensures that shelf-life is maximal. When

Aubrey F. Egan

1983-01-01

138

Bacteriocins of lactic acid bacteria: Their potentials as food biopreservative  

Microsoft Academic Search

Numerous strains of lactic acid bacteria used in the fermentation of foods are known to produce bacteriocins. In general, bacteriocins are a group of proteinaceous antimicrobial substances that inhibit the growth of closely related bacteria. However, some bacteriocins produced by lactic acid bacteria (LAB) exhibit a relatively broad antimicrobial spectrum and are active against several food?spoilage and health?threatening microorganisms. Many

Wang June Kim

1993-01-01

139

Nanoporous In2O3-based cataluminescence sensor for acetic acid vapor  

Microsoft Academic Search

In the present paper, we reported a cataluminescence (CTL) sensor using nanoporous In2O3 as sensing material to determine trace acetic acid in air. The proposed sensor showed high sensitivity and selectivity to acetic acid at optimal temperature of 293degC. Quantitative analysis was performed at a wavelength of 440 nm. The linear range of CTL intensity versus concentration of acetic acid

Xiaoan Cao; Yanqin Hu; Ying Tao

2008-01-01

140

Degradation of acetic acid with sulfate radical generated by persulfate ions photolysis  

Microsoft Academic Search

The photolysis of S2O82- was studied for the removal of acetic acid in aqueous solution and compared with the H2O2\\/UV system. The SO4- radicals generated from the UV irradiation of S2O82- ions yield a greater mineralization of acetic acid than the OH radicals. Acetic acid is oxidized by SO4- radicals without significant formation of intermediate by-products. Increasing system pH results

Justine Criquet; Nathalie Karpel Vel Leitner

2009-01-01

141

Spectrophotometric Dissociation Field Effect Kinetics of Aqueous Acetic Acid and Bromocresol Green.  

National Technical Information Service (NTIS)

The acid-base dissociation kinetics of dilute aqueous acetic acid at 25C have been investigated using a square-wave dissociation field effect apparatus with spectrophotometric detection. The acetic acid equilibrium was coupled to that of a somewhat slower...

E. M. Eyring J. J. Auborn P. Warrick

1971-01-01

142

Determination of Monochloroacetic Acid and Dichloroacetic Acid for Quality Control of Acetic Acid Chlorination Industry by Ion Chromatography  

Microsoft Academic Search

An ion chromatographic method is described for the purpose of quality control in the process of monochloroacetic acid production. Using 2.5 mM NaOH–10% methanol as eluent, the simultaneous determination of acetic acid, monochloroacetic acid, dichloroacetic acid, and Cl? was obtained in a single run. Monochloroacetic acid and dichloroacetic acid showed good linearity in the range 0.1–20 and 0.15–20 ?g\\/ml and

Feng Qu; Shifen Mou

1999-01-01

143

Leaching of spent lead acid battery paste components by sodium citrate and acetic acid.  

PubMed

A sustainable method, with minimal pollution and low energy cost in comparison with the conventional smelting methods, is proposed for treating components of spent lead-acid battery pastes in aqueous organic acid(s). In this study, PbO, PbO2, and PbSO4, the three major components in a spent lead paste, were individually reacted with a mixture of aqueous sodium citrate and acetic acid solution. Pure lead citrate precursor of Pb3(C6H5O7)2 · 3H2O is the only product crystallized in each leaching experiment. Conditions were optimized for individual lead compounds which were then used as the basis for leaching real industrial spent paste. In this work, efficient leaching process is achieved and raw material cost is reduced by using aqueous sodium citrate and acetic acid, instead of aqueous sodium citrate and citric acid as reported in a pioneering hydrometallurgical method earlier. Acetic acid is not only cheaper than citric acid but is also more effective in aiding dissolution of the lead compounds thus speeding up the leaching process in comparison with citric acid. Lead citrate is readily crystallized from the aqueous solution due to its low solubility and can be combusted to directly produce leady oxide as a precursor for making new battery pastes. PMID:23500418

Zhu, Xinfeng; He, Xiong; Yang, Jiakuan; Gao, Linxia; Liu, Jianwen; Yang, Danni; Sun, Xiaojuan; Zhang, Wei; Wang, Qin; Kumar, R Vasant

2013-04-15

144

Antimould activity of sourdough lactic acid bacteria: identification of a mixture of organic acids produced by Lactobacillus sanfrancisco CB1  

Microsoft Academic Search

Sourdough lactic acid bacteria, cultivated in wheat flour hydrolysate, produced antimould compounds. The antimould activity\\u000a varied greatly among the strains and was mainly detected within obligately heterofermentative Lactobacillus spp. Among these, Lb. sanfrancisco CB1 had the largest spectrum. It inhibited moulds related to bread spoilage such as Fusarium, Penicillium, Aspergillus and Monilia. A mixture of acetic, caproic, formic, propionic, butyric

A. Corsetti; M. Gobbetti; J. Rossi; P. Damiani

1998-01-01

145

Acetic acid and aromatics units planned in China  

SciTech Connect

The Shanghai Wujing Chemical Complex (SWCC; Shanghai) is proceeding with construction of an acetic acid plant. The 100,000-m.t./year until will use BP Chemicals carbonylation technology, originally developed by Monsanto. John Brown has been selected by China National Technical Import Corp. (CNTIC) to supply the plant, Chinese sources say. The UK contractor, which competed against Mitsui Engineering Shipbuilding (Tokyo) and Lurgi (Frankfurt), has built a similar plant for BP in the UK, although using different technology. The new plant will require 54,000 m.t./year of methanol, which is available onsite. Carbon monoxide will be delivered from a new plant. The acetic acid unit will joint two other acetic plants in China supplied some time ago by Uhde (Dortmund). SWCC is due to be integrated with two adjacent complexes to form Shanghai Pacific Chemical. Meanwhile, four groups are competing to supply a UOP-process aromatics complex for Jilin Chemical Industrial Corp. They are Toyo Engineering, Lurgi, Lucky/Foster Wheeler, and Eurotechnica. The complex will include plants with annual capacities for 115,000 m.t. of benzene, 90,000 m.t. of ortho-xylene, 93,000 m.t. of mixed xylenes, and 20,000 m.t. of toluene. The plants will form part of a $2-billion petrochemical complex based on a 300,000-m.t./year ethylene plant awarded last year to a consortium of Samsung Engineering and Linde. Downstream plants will have annual capacities for 120,000 m.t. of linear low-density polyethylene, 80,000 m.t. of ethylene oxide, 100,000 m.t. of ethylene glycol, 80,000 m.t. of phenol, 100,000 m.t. of acrylonitrile, 20,000 m.t. of sodium cyanide, 40,000 m.t. of phthalic anhydride, 40,000 m.t. of ethylene propylene rubber, 20,000 m.t. of styrene butadiene styrene, and 30,000 m.t. of acrylic fiber.

Alperowicz, N.

1993-01-27

146

Esters of Indole-3-Acetic Acid from Avena Seeds 1  

PubMed Central

The present studies showed that about 80% of the indole-3-acetic acid extractable from Avena kernels by aqueous acetone was esterified to polymers precipitable by ammonium sulfate and ethanol or acetone. The polymers were positively charged, being adsorbed to cation exchange columns at a pH of 3, or below, and eluted at a pH greater than 4. The polymers were heterogeneous with respect to size, about 5,000 to 20,000 daltons, and charge, exhibiting apparent pKa values of 4.2 and 4.7. The polymer fractions contained esterified IAA, anthrone-reactive material that liberated glucose upon acid hydrolysis, phenolic compounds, and peptidic material with a high proportion of hydrophobic amino acids. Since the esterified IAA was unstable, establishing polymer purity was not possible, and the designation IAA-glucoprotein fraction was adopted. Dehusked Avena kernels contained 8 mg/kg total IAA of which 5.5% was free and 94.5% esterified. IAA bound through a peptidic linkage was present, but in only trace amounts.

Percival, Frank W.; Bandurski, Robert S.

1976-01-01

147

Polyunsaturated fatty acid production by marine bacteria.  

PubMed

Polyunsaturated fatty acids are important in maintaining human health. Limitations associated with current sources of ?-3 fatty acids and ?-6 fatty acids, from animal and plant sources, have led to increased interest in microbial production. Marine bacteria may provide a suitable alternative, although the isolation of production strains and the identification of operating conditions must be addressed before manufacturing processes become economically viable. Marine isolate 560 was identified as an eicosapentaenoic acid (EPA) producer via GC/MS. The isolate was initially identified as Vibrio cyclitrophicus by 16S rRNA sequencing. Statistically based experimental designs were applied to the optimisation of medium components and environmental factors for the production of EPA. A Plackett-Burman design was used to screen for the effect of temperature, pH, and media components. Subsequently, the concentrations of NaCl, yeast extract, and peptone, identified as significant factors, were optimised using a central composite design. The predicted optimal combination of media components for maximum EPA production (4.8 mg/g dry weight) was determined as 7.9 g/l peptone, 16.2 g/l NaCl, and 6.2 g/l yeast extract. On transfer of this process to bioreactor cultivation, where a range of pH and DO values were tested, the maximum amount of EPA produced increased to 7.5 mg/g dry weight and 10 % of the total fatty acid. PMID:23525832

Abd Elrazak, Ahmed; Ward, Alan C; Glassey, Jarka

2013-11-01

148

Exopolysaccharides from sourdough lactic acid bacteria.  

PubMed

The use of sourdough improves the quality and increases the shelf life of bread. The positive effects are associated with metabolites produced by lactic acid bacteria (LAB) during sourdough fermentation, including organic acids, exopolysaccharides (EPS), and enzymes. EPS formed during sourdough fermentation by glycansucrase activity from sucrose influence the viscoelastic properties of the dough and beneficially affect the texture and shelf life (in particular, starch retrogradation) of bread. Accordingly, EPS have the potential to replace hydrocolloids currently used as bread improvers and meet so the consumer demands for a reduced use of food additives. In this review, the current knowledge about the functional aspects of EPS formation by sourdough LAB especially in baking applications is summarized. PMID:24499068

Galle, Sandra; Arendt, Elke K

2014-01-01

149

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares  

Microsoft Academic Search

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing

R. Ghorbani; J. Ghasemi; B. Abdollahi

2006-01-01

150

Endohyphal Bacterium Enhances Production of Indole-3-Acetic Acid by a Foliar Fungal Endophyte  

PubMed Central

Numerous plant pathogens, rhizosphere symbionts, and endophytic bacteria and yeasts produce the important phytohormone indole-3-acetic acid (IAA), often with profound effects on host plants. However, to date IAA production has not been documented among foliar endophytes -- the diverse guild of primarily filamentous Ascomycota that live within healthy, above-ground tissues of all plant species studied thus far. Recently bacteria that live within hyphae of endophytes (endohyphal bacteria) have been detected, but their effects have not been studied previously. Here we show not only that IAA is produced in vitro by a foliar endophyte (here identified as Pestalotiopsis aff. neglecta, Xylariales), but that IAA production is enhanced significantly when the endophyte hosts an endohyphal bacterium (here identified as Luteibacter sp., Xanthomonadales). Both the endophyte and the endophyte/bacterium complex appear to rely on an L-tryptophan dependent pathway for IAA synthesis. The bacterium can be isolated from the fungus when the symbiotic complex is cultivated at 36°C. In pure culture the bacterium does not produce IAA. Culture filtrate from the endophyte-bacterium complex significantly enhances growth of tomato in vitro relative to controls and to filtrate from the endophyte alone. Together these results speak to a facultative symbiosis between an endophyte and endohyphal bacterium that strongly influences IAA production, providing a new framework in which to explore endophyte-plant interactions.

Hoffman, Michele T.; Gunatilaka, Malkanthi K.; Wijeratne, Kithsiri; Gunatilaka, Leslie; Arnold, A. Elizabeth

2013-01-01

151

Distribution of D-amino acids in vinegars and involvement of lactic acid bacteria in the production of D-amino acids.  

PubMed

Levels of free D-amino acids were compared in 11 vinegars produced from different sources or through different manufacturing processes. To analyze the D- and L-amino acids, the enantiomers were initially converted into diastereomers using pre-column derivatization with o-phthaldialdehyde plus N-acethyl-L-cysteine or N-tert-butyloxycarbonyl-L-cysteine. This was followed by separation of the resultant fluorescent isoindol derivatives on an octadecylsilyl stationary phase using ultra-performance liquid chromatography. The analyses showed that the total D-amino acid level in lactic fermented tomato vinegar was very high. Furthermore, analysis of the amino acids in tomato juice samples collected after alcoholic, lactic and acetic fermentation during the production of lactic fermented tomato vinegar showed clearly that lactic fermentation is responsible for the D-amino acids production; marked increases in D-amino acids were seen during lactic fermentation, but not during alcoholic or acetic fermentation. This suggests lactic acid bacteria have a greater ability to produce D-amino acids than yeast or acetic acid bacteria. PMID:24422181

Mutaguchi, Yuta; Ohmori, Taketo; Akano, Hirofumi; Doi, Katsumi; Ohshima, Toshihisa

2013-01-01

152

Gluconacetobacter maltaceti sp. nov., a novel vinegar producing acetic acid bacterium.  

PubMed

Comparison of HaeIII- and HpaII-restriction profiles of PCR-amplified 16S-23S rDNA ITS regions of Gluconacetobacter sp. LMG 1529(T) and SKU 1109 with restriction profiles of reference strains of acetic acid bacteria described by Tr?ek and Teuber [34] revealed the same but unique restriction profiles for LMG 1529(T) and SKU 1109. Further analyses of nearly complete 16S rRNA gene sequences, nearly complete 16S-23S rDNA ITS sequences, as well as concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, allocated both strains to a single phylogenetic cluster well separated from the other species of the genus Gluconacetobacter. DNA-DNA hybridizations confirmed their novel species identity by 73% DNA-DNA relatedness between both strains, and values below the species level (<70%) between SKU 1109 and the type strains of the closest phylogenetic neighbors. The classification of strains LMG 1529(T) and SKU 1109 into a single novel species was confirmed also by AFLP and (GTG)(5)-PCR DNA fingerprinting data, as well as by phenotypic data. Strains LMG 1529(T) and SKU 1109 can be differentiated from their closely related Gluconacetobacter species, Gluconacetobacter entanii and Gluconacetobacter hansenii, by their ability to form 2-keto-d-gluconic acid from d-glucose, their ability to use d-mannitol, d-gluconate and glycerol as carbon source and form acid from d-fructose, and their ability to grow without acetic acid. The major fatty acid of LMG 1529(T) and SKU 1109 is C(18:1?7c) (60.2-64.8%). The DNA G+C content of LMG 1529(T) and SKU 1109 is 62.5 and 63.3mol% respectively. The name Gluconacetobacter maltaceti sp. nov. is proposed. The type strain is LMG 1529(T) (=NBRC 14815(T)=NCIMB 8752(T)). PMID:23273842

Slapšak, Nina; Cleenwerck, Ilse; De Vos, Paul; Tr?ek, Janja

2013-02-01

153

[Advances in functional genomics studies underlying acetic acid tolerance of Saccharomyces cerevisiae].  

PubMed

Industrial microorganisms are subject to various stress conditions, including products and substrates inhibitions. Therefore, improvement of stress tolerance is of great importance for industrial microbial production. Acetic acid is one of the major inhibitors in the cellulosic hydrolysates, which affects seriously on cell growth and metabolism of Saccharomyces cerevisiae. Studies on the molecular mechanisms underlying adaptive response and tolerance of acetic acid of S. cerevisiae benefit breeding of robust strains of industrial yeast for more efficient production. In recent years, more insights into the molecular mechanisms underlying acetic acid tolerance have been revealed through analysis of global gene expression and metabolomics analysis, as well as phenomics analysis by single gene deletion libraries. Novel genes related to response to acetic acid and improvement of acetic acid tolerance have been identified, and novel strains with improved acetic acid tolerance were constructed by modifying key genes. Metal ions including potassium and zinc play important roles in acetic acid tolerance in S. cerevisiae, and the effect of zinc was first discovered in our previous studies on flocculating yeast. Genes involved in cell wall remodeling, membrane transport, energy metabolism, amino acid biosynthesis and transport, as well as global transcription regulation were discussed. Exploration and modification of the molecular mechanisms of yeast acetic acid tolerance will be done further on levels such as post-translational modifications and synthetic biology and engineering; and the knowledge obtained will pave the way for breeding robust strains for more efficient bioconversion of cellulosic materials to produce biofuels and bio-based chemicals. PMID:25007573

Zhao, Xinqing; Zhang, Mingming; Xu, Guihong; Xu, Jianren; Bai, Fengwu

2014-03-01

154

Atmospheric geochemistry of formic and acetic acids at a mid-latitude temperate site  

NASA Technical Reports Server (NTRS)

Tropospheric concentrations of formic and acetic acids in the gas, the aerosol, and the rainwater phases were determined in samples collected 1-2 m above ground level at an open field site in eastern Virginia. These acids were found to occur principally (98 percent or above) in the gas phase, with a marked annual seasonality, averaging 1890 ppt for formate and 1310 ppt for acetate during the growing season, as compared to 695 ppt and 700 ppt, respectively, over the nongrowing season. The data support the hypothesis that biogenic emissions from vegatation are important sources of atmospheric formic and acetic acid during the local growing season. The same time trends were observed for precipitation, although with less defined seasonality. The relative increase of the acetic acid/formic acid ratio during the nongrowing season points to the dominance of anthropogenic inputs of acetic acid from motor vehicles and biomass combustion in the wintertime.

Talbot, R. W.; Beecher, K. M.; Harriss, R. C.; Cofer, R. W., III

1988-01-01

155

Biogenic amines in wines: role of lactic acid bacteria  

Microsoft Academic Search

Biogenic amines have undesirable physiological effects when absorbed at too high a concentration. Several kinds of food and beverages contain biogenic amines. Lactic acid bacteria can decarboxylate amino acids. Since winemaking involves the growth of lactic acid bacteria for malolactic fermentation, biogenic amines may occur. However, not all bacterial strains carry these activities. In the same wine-producing area, some wines

Aline Lonvaud-Funel

2001-01-01

156

Phase preference by active, acetate-utilizing bacteria at the rifle, CO integrated field research challenge site.  

PubMed

Previous experiments at the Rifle, Colorado Integrated Field Research Challenge (IFRC) site demonstrated that field-scale addition of acetate to groundwater reduced the ambient soluble uranium concentration. In this report, sediment samples collected before and after acetate field addition were used to assess the active microbes via (13)C acetate stable isotope probing on 3 phases [coarse sand, fines (8-approximately 150 ?m), groundwater (0.2-8 ?m)] over a 24-day time frame. TRFLP results generally indicated a stronger signal in (13)C-DNA in the "fines" fraction compared to the sand and groundwater. Before the field-scale acetate addition, a Geobacter-like group primarily synthesized (13)C-DNA in the groundwater phase, an alpha Proteobacterium primarily grew on the fines/sands, and an Acinetobacter sp. and Decholoromonas-like OTU utilized much of the (13)C acetate in both groundwater and particle-associated phases. At the termination of the field-scale acetate addition, the Geobacter-like species was active on the solid phases rather than the groundwater, while the other bacterial groups had very reduced newly synthesized DNA signal. These findings will help to delineate the acetate utilization patterns of bacteria in the field and can lead to improved methods for stimulating distinct microbial populations in situ. PMID:21226528

Kerkhof, Lee J; Williams, Ken H; Long, Philip E; McGuinness, Lora R

2011-02-15

157

1 H and 13 C NMR observation of the reaction of acetic acid with titanium isopropoxide  

Microsoft Academic Search

Hydrogen and carbon NMR spectroscopy have been used to investigate the chemical modification process of titanium isopropoxide by acetic acid. The spectra confirm the belief that the titanium isopropoxide exchanges isopropyl groups with modifying acetate groups to form a molecule with approximate stoichiometry Ti(OiPr)2(OAc)2. This stoichiometry results even when enough acetic acid is present in solution to allow for significantly

Dunbar P Birnie III; Norbert J. Bendzko

1999-01-01

158

Acetic acid: Microwave spectra, internal rotation and substitution structure  

NASA Astrophysics Data System (ADS)

The internal rotation splittings in the microwave spectrum of acetic acid have been re-examined, using both principal axis method (PAM) and internal axis method (IAM) treatments. It is shown how individual terms in the PAM equation can be correlated to the first terms in an expansion of the corresponding IAM formula. When centrifugal distortion was allowed for, both methods reproduced the A-type frequencies within experimental error. For the E-type lines the r.m.s. deviation was 1.64 MHz in the PAM (using Wv? ( n) -terms with n = 1, 2, …, 14, d, e, f) and 0.70 MHz in the IAM. To derive the substitution structure eight isotopic species were studied. The inertial moments of the molecules with various degrees of methyl group deuteration are not consistent with each other, so these data could not be fully used. Therefore, the structure was derived with the assumption of a cylindrically symmetric methyl group, although there is some evidence that the HCH angles differ by a few degrees. The geometry, which is in agreement with earlier electron diffraction results, is compared with the substitution structures of other carboxylic acids.

van Eijck, B. P.; van Opheusden, J.; van Schaik, M. M. M.; van Zoeren, E.

1981-04-01

159

A comparison of the esterification of acetic acid with methanol using heterogeneous versus homogeneous acid catalysis  

Microsoft Academic Search

To investigate the similarities and differences between heterogeneous and homogeneous catalyzed esterification, the kinetics of acetic acid esterification with methanol were investigated using a commercial Nafion\\/silica nanocomposite catalyst (SAC-13) and H2SO4, respectively. Reactions were carried out in an isothermal well-mixed batch reactor at 60?°C. Organic base titration, TGA, and elemental sulfur analysis were carried out to estimate the acid site

Yijun Liu; Edgar Lotero; James G. Goodwin

2006-01-01

160

Polymerization of vinyl acetate in fatty acids and properties of poly (vinyl alcohols) derived from the poly (vinyl acetates)  

Microsoft Academic Search

Polymerization of vinyl acetate (VAc) in various fatty acids (carbon numbers 4–18) was carried out. Chain transfer constants to the acids were determined to be 20–35×10-4, from which the constant to a methylene group was obtained to be 0.73×10-4. Viscometry in aqueous solution of derived poly (vinyl alcohol) (PVA) showed the usual behavior in terms of Huggins’ constant obtained by

Takeshi Ishijima; Yoshiki Mizumori; Kenji Kikuchi; Atsushi Suzuki; Takuji Okaya

2005-01-01

161

Beneficial effects of lactic acid bacteria on human beings.  

PubMed

Lactic acid bacteria are a diverse group of bacteria that produce lactic acid as their major fermented product. Most of them are normal flora of human being and animals and produce myriad beneficial effects for human beings include, alleviation of lactose intolerance, diarrhea, peptic ulcer, stimulation of immune system, antiallergic effects, antifungal actions, preservation of food, and prevention of colon cancer. This review highlights the potential species of Lactic acid bacteria responsible for producing these effects. It has been concluded that lactic acid bacteria are highly beneficial microorganisms for human beings and are present abundantly in dairy products so their use should be promoted for good human health. PMID:21162695

Masood, Muhammad Irfan; Qadir, Muhammad Imran; Shirazi, Jafir Hussain; Khan, Ikram Ullah

2011-02-01

162

21 CFR 862.1390 - 5-Hydroxyindole acetic acid/serotonin test system.  

Code of Federal Regulations, 2010 CFR

...acid/serotonin in urine. Measurements of 5-hydroxyindole acetic acid/serotonin are used in the diagnosis and treatment of carcinoid tumors of endocrine tissue. (b) Classification. Class I (general controls). The device is exempt from the...

2010-04-01

163

21 CFR 862.1390 - 5-Hydroxyindole acetic acid/serotonin test system.  

Code of Federal Regulations, 2010 CFR

...acid/serotonin in urine. Measurements of 5-hydroxyindole acetic acid/serotonin are used in the diagnosis and treatment of carcinoid tumors of endocrine tissue. (b) Classification. Class I (general controls). The device is exempt from the...

2009-04-01

164

Ethenzamide-gentisic acid-acetic acid (2/1/1)  

PubMed Central

In the title co-crystal solvate, 2-ethoxy­benzamide–2,5-dihydroxy­benzoic acid–ethanoic acid (2/1/1), 2C9H11NO2·C7H6O4·C2H4O2, two nonsteroidal anti-inflammatory drugs, ethenzamide (systematic name: 2-ethoxy­benzamide) and gentisic acid (systematic name: 2,5-dihydroxy­benzoic acid), together with acetic acid (systematic name: ethanoic acid) form a four-component mol­ecular assembly held together by N—H?O and O—H?O hydrogen bonds. This assembly features two symmetry-independent mol­ecules of ethenzamide, forming supra­molecular acid–amide heterosynthons with gentisic acid and acetic acid. These heterosynthons involve quite strong O—H?O [O?O = 2.5446?(15) and 2.5327?(15)?Å] and less strong N—H?O [N?O = 2.9550?(17) and 2.9542?(17)?Å] hydrogen bonds. The overall crystal packing features several C—H?O and ?–? stacking inter­actions [centroid–centroid distance = 3.7792?(11)?Å].

Aitipamula, Srinivasulu; Chow, Pui Shan; Tan, Reginald B.H.

2010-01-01

165

Kozakia baliensis gen. nov., sp. nov., a novel acetic acid bacterium in the alpha-proteobacteria.  

PubMed

Four bacterial strains were isolated from palm brown sugar and ragi collected in Bali and Yogyakarta, Indonesia, by an enrichment culture approach for acetic acid bacteria. Phylogenetic analysis based on 16S rRNA gene sequences showed that the four isolates constituted a cluster separate from the genera Acetobacter, Gluconobacter, Acidomonas, Gluconacetobacter and Asaia with a high bootstrap value in a phylogenetic tree. The isolates had high values of DNA-DNA similarity (78-100%) between one another and low values of the similarity (7-25%) to the type strains of Acetobacter aceti, Gluconobacter oxydans, Gluconacetobacter liquefaciens and Asaia bogorensis. The DNA base composition of the isolates ranged from 56.8 to 57.2 mol% G+C with a range of 0-4 mol%. The major quinone was Q-10. The isolates oxidized acetate and lactate to carbon dioxide and water, but the activity was weak, as with strains of Asaia bogorensis. The isolates differed from Asaia bogorensis strains in phenotypic characteristics. The name Kozakia baliensis gen. nov., sp. nov., is proposed for the four isolates. Strain Yo-3T (= NRIC 0488T = JCM 11301T = IFO 16664T = DSM 14400T) was isolated from palm brown sugar collected in Bali, Indonesia, and was designated as the type strain. PMID:12054243

Lisdiyanti, Puspita; Kawasaki, Hiroko; Widyastuti, Yantyati; Saono, Susono; Seki, Tatsuji; Yamada, Yuzo; Uchimura, Tai; Komagata, Kazuo

2002-05-01

166

Radioimmunoassay of 5-hydroxyindole acetic acid using an iodinated derivative  

SciTech Connect

A radioimmunoassay for the main catabolite of serotonin, 5-hydroxyindole acetic acid (5-HIAA), was developed by using specific antibodies and iodinated derivative. The synthesis of a /sup 125/I-iodinated analog was performed by coupling 5-HIAA to (125I-)glycyl-tyrosine without any contact between 5-HIAA and iodine or chloramine T. It was purified on a G25 Sephadex column and diluted in citrate buffer up to 2.5 X 10(5) cpm/ml. Antibodies were obtained by coupling 5-HIAA to human serum albumin with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and tested by equilibrium dialysis. After the third immunogen injection, the four rabbits gave antisera capable of binding 50% of iodinated 5-HIIA-glycyl-tyrosine at 1/2000 final dilution. A chemical conversion of the biological samples gives to the antigen molecules a better resemblance to the immunogen, thus conferring a 100-fold gain in specificity and sensitivity. This assay allows 5-HIAA to be determined in small amounts of tissue, blood, cerebrospinal fluid or perfusate without purification with a sensitivity threshold below 0.1 ng. Some applications in cat and rat are presented.

Puizillout, J.J.; Delaage, M.A.

1981-06-01

167

Metabolic regulation of the plant hormone indole-3-acetic acid  

SciTech Connect

The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.

Jerry D. Cohen

2009-11-01

168

IR plus vacuum ultraviolet spectroscopy of neutral and ionic organic acid molecules and clusters: acetic acid.  

PubMed

Infrared (IR) vibrational spectroscopy of acetic acid (A) neutral and ionic monomers and clusters, employing vacuum ultraviolet (VUV), 10.5 eV single photon ionization of supersonically expanded and cooled acetic acid samples, is presented and discussed. Molecular and cluster species are identified by time of flight mass spectroscopy: the major mass features observed are A(n)H(+) (n=1-9), ACOOH(+) (VUV ionization) without IR radiation present, and A(+) with both IR and VUV radiation present. The intense feature ACOOH(+) arises from the cleavage of (A)(2) at the beta-CC bond to generate ACOOH(+)+CH(3) following ionization. The vibrational spectrum of monomeric acetic acid (2500-7500 cm(-1)) is measured by nonresonant ionization detected infrared (NRID-IR) spectroscopy. The fundamentals and overtones of the CH and OH stretches and some combination bands are identified in the spectrum. Mass selected IR spectra of neutral and cationic acetic acid clusters are measured in the 2500-3800 cm(-1) range employing nonresonant ionization dip-IR and IR photodissociation (IRPD) spectroscopies, respectively. Characteristic bands observed at approximately 2500-2900 cm(-1) for the cyclic ring dimer are identified and tentatively assigned. For large neutral acetic acid clusters A(n)(n>2), spectra display only hydrogen bonded OH stretch features, while the CH modes (2500-2900 cm(-1)) do not change with cluster size n. The IRPD spectra of protonated (cationic) acetic acid clusters A(n)H(+) (n=1-7) exhibit a blueshift of the free OH stretch with increasing n. These bands finally disappear for n> or =6, and one broad and weak band due to hydrogen bonded OH stretch vibrations at approximately 3350 cm(-1) is detected. These results indicate that at least one OH group is not involved in the hydrogen bonding network for the smaller (n< or =5) A(n)H(+) species. The disappearance of the free OH stretch feature at n> or =6 suggests that closed cyclic structures form for A(n)H(+) for the larger clusters (n> or =6). PMID:17115753

Hu, Y J; Fu, H B; Bernstein, E R

2006-11-14

169

Ameyamaea chiangmaiensis gen. nov., sp. nov., an acetic acid bacterium in the alpha-Proteobacteria.  

PubMed

Two isolates, AC04(T) and AC05, were isolated from the flowers of red ginger collected in Chiang Mai, Thailand. In phylogenetic trees based on 16S rRNA gene sequences, the two isolates were included within a lineage comprised of the genera Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Neoasaia, Granulibacter, and Tanticharoenia, and they formed an independent cluster along with the type strain of Tanticharoenia sakaeratensis. The calculated pair-wise sequence similarities of isolate AC04(T) were 97.8-92.5% to the type strains of the type species of the 11 genera of acetic acid bacteria. The DNA base composition was 66.0-66.1 mol % G+C with a range of 0.1 mol %. A single-stranded, labeled DNA from isolate AC04(T) presented levels of DNA-DNA hybridization of 100, 85, 4, and 3% respectively to DNAs from isolates AC04(T) and AC05 and the type strains of Tanticharoenia sakaeratensis and Gluconacetobacter liquefaciens. The two isolates were unique morphologically in polar flagellation and physiologically in intense acetate oxidation to carbon dioxide and water and weak lactate oxidation. The intensity in acetate oxidation almost equaled that of the type strain of Acetobacter aceti. The two isolates had Q-10. Isolate AC04(T) was discriminated from the type strains of the type species of the 11 genera by 16S rRNA gene restriction analysis using restriction endonucleases TaqI and Hin6I. The unique phylogenetic, genetic, morphological, physiological, and biochemical characteristics obtained indicate that the two isolates can be classified into a separate genus, and Ameyamaea chiangmaiensis gen. nov., sp. nov. is proposed. The type strain is isolate AC04(T) (=BCC 15744(T), =NBRC 103196(T)), which has a DNA G+C content of 66.0 mol %. PMID:19809199

Yukphan, Pattaraporn; Malimas, Taweesak; Muramatsu, Yuki; Takahashi, Mai; Kaneyasu, Mika; Potacharoen, Wanchern; Tanasupawat, Somboon; Nakagawa, Yasuyoshi; Hamana, Koei; Tahara, Yasutaka; Suzuki, Ken-ichiro; Tanticharoen, Morakot; Yamada, Yuzo

2009-10-01

170

Beneficial Effect of Acetic Acid on the Xylose Utilization and Bacterial Cellulose Production by Gluconacetobacter xylinus.  

PubMed

In this work, acetic acid was found as one promising substrate to improve xylose utilization by Gluconacetobacter xylinus CH001. Also, with the help of adding acetic acid into medium, the bacterial cellulose (BC) production by G. xylinus was increased significantly. In the medium containing 3 g l(-1) acetic acid, the optimal xylose concentration for BC production was 20 g l(-1). In the medium containing 20 g l(-1) xylose, the xylose utilization and BC production by G. xylinus were stimulated by acetic acid within certain concentration. The highest BC yield (1.35 ± 0.06 g l(-1)) was obtained in the medium containing 20 g l(-1) xylose and 3 g l(-1) acetic acid after 14 days. This value was 6.17-fold higher than the yield (0.21 ± 0.01 g l(-1)) in the medium only containing 20 g l(-1) xylose. The results analyzed by FE-SEM, FTIR, and XRD showed that acetic acid affected little on the microscopic morphology and physicochemical characteristics of BC. Base on the phenomenon observed, lignocellulosic acid hydrolysates (xylose and acetic acid are main carbon sources present in it) could be considered as one potential substrate for BC production. PMID:24891733

Yang, Xiao-Yan; Huang, Chao; Guo, Hai-Jun; Xiong, Lian; Luo, Jun; Wang, Bo; Chen, Xue-Fang; Lin, Xiao-Qing; Chen, Xin-De

2014-09-01

171

Production of indole-3-acetic acid and gibberellins A 1 and A 3 by Acetobacter diazotrophicus and Herbaspirillum seropedicae in chemically-defined culture media  

Microsoft Academic Search

The characterization by capillary gas chromatography-mass spectrometry of the plant hormones indole-3-acetic acid and the gibberellins GA1 and GA3 from chemically-defined cultures of Acetobacter diazotrophicus and Herbaspirillum seropedicae is reported. Both bacteria are endophytic in gramineae species where they promote growth and yield. Quantification was also done by selected ion monitoring with [17,17-2H2]-Gibberellin A1, [17,17-2H2]-Gibberellin A3 and [13C6]-indole-3-acetic acid as

Fabiola Bastián; Ana Cohen; Patricia Piccoli; Virgina Luna; Rita Baraldi; Rubén Bottini

1998-01-01

172

Occurrence of a furan fatty acid in marine bacteria.  

PubMed

A fatty acid containing a furan ring was detected in the cellular lipids of marine bacteria, Shewanella putrefaciens, Marinomonas comunis, Enterobacter agglomerans, Pseudomonas fluorescens, etc., which were isolated from the intestinal liquor of fishes. Analytical data indicated that the fatty acid was 10,13-epoxy-11-methyloctadeca-10, 12-dienoic acid. Therefore, we propose that furan fatty acids detected in marine fish are derived not only from marine plants but also from intestinal bacteria of fishes. PMID:7548190

Shirasaka, N; Nishi, K; Shimizu, S

1995-10-01

173

Fermentation of Fructooligosaccharides by Lactic Acid Bacteria and Bifidobacteria  

Microsoft Academic Search

Lactic acid bacteria and bifidobacteria were screened of their ability to ferment fructooligosaccharides (FOS) on MRS agar. Of 28 strains of lactic acid bacteria and bifidobacteria examined, 12 of 16 Lactobacillus strains and 7 of 8 Bifidobacterium strains fermented FOS. Only strains that gave a positive reaction by the agar method reached high cell densities in broth containing FOS.

Handan Kaplan; Robert W. Hutkins

2000-01-01

174

The sourdough microflora: Interactions of lactic acid bacteria and yeasts  

Microsoft Academic Search

Sourdough bread is a traditional product with great potential. This can only be achieved if the interactions between the lactic acid bacteria and yeasts that populate the sourdough are understood. The trophic and non-trophic interactions between sourdough lactic acid bacteria and yeasts are reviewed with particular emphasis on the metabolism of the carbohydrates and nitrogen compounds, the production of CO2

M Gobbetti

1998-01-01

175

Purification of bacteriocins of lactic acid bacteria: problems and pointers  

Microsoft Academic Search

Bacteriocins of lactic acid bacteria have been widely studied in recent years. However, there are relatively few studies that describe their biochemical structure. This may be due to the many challenges associated with the purification of these antimicrobial peptides. This review focuses on the purification procedures used with bacteriocins of lactic acid bacteria and conveys some of the problems associated

Verna Carolissen-Mackay; Gottlieb Arendse; John W. Hastings

1997-01-01

176

Lactic acid bacteria of foods and their current taxonomy  

Microsoft Academic Search

Application of molecular genetic techniques to determine the relatedness of food-associated lactic acid bacteria has resulted in significant changes in their taxonomic classification. During the 1980s the genus Streptococcus was separated into the three genera Enterococcus, Lactococcus and Streptococcus. The lactic acid bacteria associated with foods now include species of the genera Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus,

Michael E. Stiles; Wilhelm H. Holzapfel

1997-01-01

177

Modulation of Endogenous Indole-3-Acetic Acid Biosynthesis in Bacteroids within Medicago sativa Nodules.  

PubMed

To evaluate the dose-response effects of endogenous indole-3-acetic acid (IAA) on Medicago plant growth and dry weight production, we increased the synthesis of IAA in both free-living and symbiosis-stage rhizobial bacteroids during Rhizobium-legume symbiosis. For this purpose, site-directed mutagenesis was applied to modify an 85-bp promoter sequence, driving the expression of iaaM and tms2 genes for IAA biosynthesis. A positive correlation was found between the higher expression of IAA biosynthetic genes in free-living bacteria and the increased production of IAA under both free-living and symbiotic conditions. Plants nodulated by RD65 and RD66 strains, synthetizing the highest IAA concentration, showed a significant (up to 73%) increase in the shoot fresh weight and upregulation of nitrogenase gene, nifH, compared to plants nodulated by the wild-type strain. When these plants were analyzed by confocal microscopy, using an anti-IAA antibody, the strongest signal was observed in bacteroids of Medicago sativa RD66 (Ms-RD66) plants, even when they were located in the senescent nodule zone. We show here a simple system to modulate endogenous IAA biosynthesis in bacteria nodulating legumes suitable to investigate which is the maximum level of IAA biosynthesis, resulting in the maximal increase of plant growth. PMID:24814784

Bianco, C; Senatore, B; Arbucci, S; Pieraccini, G; Defez, R

2014-07-15

178

Amino acid catabolic pathways of lactic acid bacteria.  

PubMed

Lactic acid bacteria (LAB) constitute a diverse group of Gram positive obligately fermentative microorganisms which include both beneficial and pathogenic strains. LAB generally have complex nutritional requirements and therefore they are usually associated with nutrient-rich environments such as animal bodies, plants and foodstuffs. Amino acids represent an important resource for LAB and their utilization serves a number of physiological roles such as intracellular pH control, generation of metabolic energy or redox power, and resistance to stress. As a consequence, the regulation of amino acid catabolism involves a wide set of both general and specific regulators and shows significant differences among LAB. Moreover, due to their fermentative metabolism, LAB amino acid catabolic pathways in some cases differ significantly from those described in best studied prokaryotic model organisms such as Escherichia coli or Bacillus subtilis. Thus, LAB amino acid catabolism constitutes an interesting case for the study of metabolic pathways. Furthermore, LAB are involved in the production of a great variety of fermented products so that the products of amino acid catabolism are also relevant for the safety and the quality of fermented products. PMID:16893752

Fernández, María; Zúñiga, Manuel

2006-01-01

179

Acetic Acid Production by an Electrodialysis Fermentation Method with a Computerized Control System  

PubMed Central

In acetic acid fermentation by Acetobacter aceti, the acetic acid produced inhibits the production of acetic acid by this microorganism. To alleviate this inhibitory effect, we developed an electrodialysis fermentation method such that acetic acid is continuously removed from the broth. The fermentation unit has a computerized system for the control of the pH and the concentration of ethanol in the fermentation broth. The electrodialysis fermentation system resulted in improved cell growth and higher productivity over an extended period; the productivity exceeded that from non-pH-controlled fermentation. During electrodialysis fermentation in our system, 97.6 g of acetic acid was produced from 86.0 g of ethanol; the amount of acetic acid was about 2.4 times greater than that produced by non-pH-controlled fermentation (40.1 g of acetic acid produced from 33.8 g of ethanol). Maximum productivity of electrodialysis fermentation in our system was 2.13 g/h, a rate which was 1.35 times higher than that of non-pH-controlled fermentation (1.58 g/h).

Nomura, Yoshiyuki; Iwahara, Masayoshi; Hongo, Motoyoshi

1988-01-01

180

Corrosion inhibition of indole-3-acetic acid on mild steel in 0.5 M HCl  

Microsoft Academic Search

Corrosion inhibition of indole-3-acetic acid on mild steel in acidic medium (0.5M HCl) containing the desired amount of inhibitor has been investigated at different temperatures by using potentiodynamic polarization, electrochemical impedance spectroscopy, and polarization resistance measurements. The experimental results showed that corrosion potential shifted toward a more negative potential region in the presence of indole-3-acetic acid than that of blank

Gül?en Avci

2008-01-01

181

Indole-3-Acetic Acid Biosynthesis in Colletotrichum gloeosporioides f. sp. aeschynomene  

PubMed Central

We characterized the biosynthesis of indole-3-acetic acid by the mycoherbicide Colletotrichum gloeosporioides f. sp. aeschynomene. Auxin production was tryptophan dependent. Compounds from the indole-3-acetamide and indole-3-pyruvic acid pathways were detected in culture filtrates. Feeding experiments and in vitro assay confirmed the presence of both pathways. Indole-3-acetamide was the major pathway utilized by the fungus to produce indole-3-acetic acid in culture.

Robinson, M.; Riov, J.; Sharon, A.

1998-01-01

182

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7 ? †  

PubMed Central

Microbiological safety has been a critical issue for acid and acidified foods since it became clear that acid-tolerant pathogens such as Escherichia coli O157:H7 can survive (even though they are unable to grow) in a pH range of 3 to 4, which is typical for these classes of food products. The primary antimicrobial compounds in these products are acetic acid and NaCl, which can alter the intracellular physiology of E. coli O157:H7, leading to cell death. For combinations of acetic acid and NaCl at pH 3.2 (a pH value typical for non-heat-processed acidified vegetables), survival curves were described by using a Weibull model. The data revealed a protective effect of NaCl concentration on cell survival for selected acetic acid concentrations. The intracellular pH of an E. coli O157:H7 strain exposed to acetic acid concentrations of up to 40 mM and NaCl concentrations between 2 and 4% was determined. A reduction in the intracellular pH was observed for increasing acetic acid concentrations with an external pH of 3.2. Comparing intracellular pH with Weibull model predictions showed that decreases in intracellular pH were significantly correlated with the corresponding times required to achieve a 5-log reduction in the number of bacteria.

Hosein, Althea M.; Breidt, Frederick; Smith, Charles E.

2011-01-01

183

5-Fluoroindole-3-acetic acid: a prodrug activated by a peroxidase with potential for use in targeted cancer therapy  

Microsoft Academic Search

Indole-3-acetic acid and some derivatives are oxidized by horseradish peroxidase, forming a radical-cation that rapidly fragments (eliminating CO2) to form cytotoxic products. No toxicity is seen when either indole-3-acetic acid or horseradish peroxidase is incubated alone at concentrations that together form potent cytotoxins. Unexpectedly, 5-fluoroindole-3-acetic acid, which is oxidized by horseradish peroxidase compound I 10-fold more slowly than indole-3-acetic acid,

Lisa K Folkes; Olga Greco; Gabi U Dachs; Michael R. L Stratford; Peter Wardman

2002-01-01

184

Migration of ethylene glycol from polyethylene terephthalate bottles into 3% acetic acid.  

PubMed

Migration of ethylene glycol (EG) from polyethylene terephthalate (PET) bottles into the food simulate 3% acetic acid was studied using 32 fluid oz PET bottles filled with 3% acetic acid and stored at 32 degrees C for 6 months. Final concentration of EG in the 3% acetic acid migration solution was about 100 ppb, which is equivalent to about 94 microgram EG/bottle. A gas-liquid chromatographic procedure for quantitating EG was developed which is capable of measuring EG levels as low as 50 ppb in the migration solution. PMID:6448834

Kashtock, M; Breder, C V

1980-03-01

185

Biosynthesis of the Halogenated Auxin, 4-Chloroindole-3-Acetic Acid1[W][OA  

PubMed Central

Seeds of several agriculturally important legumes are rich sources of the only halogenated plant hormone, 4-chloroindole-3-acetic acid. However, the biosynthesis of this auxin is poorly understood. Here, we show that in pea (Pisum sativum) seeds, 4-chloroindole-3-acetic acid is synthesized via the novel intermediate 4-chloroindole-3-pyruvic acid, which is produced from 4-chlorotryptophan by two aminotransferases, TRYPTOPHAN AMINOTRANSFERASE RELATED1 and TRYPTOPHAN AMINOTRANSFERASE RELATED2. We characterize a tar2 mutant, obtained by Targeting Induced Local Lesions in Genomes, the seeds of which contain dramatically reduced 4-chloroindole-3-acetic acid levels as they mature. We also show that the widespread auxin, indole-3-acetic acid, is synthesized by a parallel pathway in pea.

Tivendale, Nathan D.; Davidson, Sandra E.; Davies, Noel W.; Smith, Jason A.; Dalmais, Marion; Bendahmane, Abdelhafid I.; Quittenden, Laura J.; Sutton, Lily; Bala, Raj K.; Le Signor, Christine; Thompson, Richard; Horne, James; Reid, James B.; Ross, John J.

2012-01-01

186

Theophylline-7-acetic acid derivatives with amino acids as anti-tuberculosis agents.  

PubMed

A series of amides were synthesized by condensation of theophylline-7-acetic acid and eight commercially available amino acid methyl ester hydrochlorides. Consecutive hydrolysis of six of the amido-esters resulted in the formation of corresponding amido-acids. The newly synthesized compounds were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv. The activity varied depending on the amino acid fragments and in seven cases exerted excellent values with MICs 0.46-0.26?M. Assessment of the cytotoxicity revealed that the compounds were not cytotoxic against the human embryonal kidney cell line HEK-293T. The theophylline-7-acetamides containing amino acid moieties appear to be promising lead compounds for the development of antimycobacterial agents. PMID:24878196

Voynikov, Yulian; Valcheva, Violeta; Momekov, Georgi; Peikov, Plamen; Stavrakov, Georgi

2014-07-15

187

Pervaporation of acetic acid\\/water mixtures through carbon molecular sieve-filled PDMS membranes  

Microsoft Academic Search

The pervaporation process for acetic\\/water has been investigated with carbon molecular sieve (CMS)-filled polydimethylsiloxane (PDMS) membranes. The effects of feed temperature, feed acetic acid concentration and CMS content on the performance of the membranes have been studied. It is found that the addition of CMS can improve pervaporation behavior of PDMS membranes to some extent and greatly increases the strength

Lei Li; Zeyi Xiao; Zhibing Zhang; Shujuan Tan

2004-01-01

188

Effect of Acetic Acid Supplementation on Egg Quality Characteristics of Commercial Laying Hens during Hot Season  

Microsoft Academic Search

This study was conducted to determine the effects of acetic acid supplement at four levels (control, 200, 400 and 600-ppm in drinking water) on egg production and quality in commercial Brown Leghorn reared birds during the hot season (32°C). One hundred and sixty 30 week-old laying birds were randomly divided into 4 groups and subjected to four levels of acetic

I. T. Kadim; W. Al-Marzooqi; O. Mahgoub; A. Al-Jabri; S. K. Al-Waheebi

2008-01-01

189

Scaleable Production and Separation of Fermentation-Derived Acetic Acid. Final CRADA report.  

National Technical Information Service (NTIS)

Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic const...

S. W. Snyder

2010-01-01

190

Lactic acid bacteria from fermented table olives.  

PubMed

Table olives are one of the main fermented vegetables in the world. Olives can be processed as treated or natural. Both have to be fermented but treated green olives have to undergo an alkaline treatment before they are placed in brine to start their fermentation. It has been generally established that lactic acid bacteria (LAB) are responsible for the fermentation of treated olives. However, LAB and yeasts compete for the fermentation of natural olives. Yeasts play a minor role in some cases, contributing to the flavour and aroma of table olives and in LAB development. The main microbial genus isolated in table olives is Lactobacillus. Other genera of LAB have also been isolated but to a lesser extent. Lactobacillus plantarum and Lactobacillus pentosus are the predominant species in most fermentations. Factors influencing the correct development of fermentation and LAB, such as pH, temperature, the amount of NaCl, the polyphenol content or the availability of nutrients are also reviewed. Finally, current research topics on LAB from table olives are reviewed, such as using starters, methods of detection and identification of LAB, their production of bacteriocins, and the possibility of using table olives as probiotics. PMID:22475936

Hurtado, Albert; Reguant, Cristina; Bordons, Albert; Rozès, Nicolas

2012-08-01

191

Acute intestinal injury induced by acetic acid and casein: prevention by intraluminal misoprostol  

SciTech Connect

Acute injury was established in anesthetized rabbits by intraluminal administration of acetic acid with and without bovine casein, into loops of distal small intestine. Damage was quantified after 45 minutes by the blood-to-lumen movement of {sup 51}Cr-labeled ethylenediaminetetraacetic acid (EDTA) and fluorescein isothiocyanate-tagged bovine serum albumin as well as luminal fluid histamine levels. The amount of titratable acetic acid used to lower the pH of the treatment solutions to pH 4.0 was increased by the addition of calcium gluconate. Luminal acetic acid caused a 19-fold increase in {sup 51}Cr-EDTA accumulation over saline controls; casein did not modify this effect. In saline controls, loop fluid histamine levels bordered on the limits of detection (1 ng/g) but were elevated 19-fold by acetic acid exposure and markedly increased (118-fold) by the combination of acid and casein. Intraluminal misoprostol (3 or 30 micrograms/mL), administered 30 minutes before acetic acid, significantly attenuated the increase in epithelial permeability (luminal {sup 51}Cr-EDTA, fluorescein isothiocyanate-bovine serum albumin accumulation) and histamine release (P less than 0.05). Diphenhydramine, alone or in combination with cimetidine, and indomethacin (5 mg/kg IV) were not protective. It is concluded that exposure of the epithelium to acetic acid promotes the transepithelial movement of casein leading to enhanced mast cell activation and mucosal injury. Damage to the epithelial barrier can be prevented by misoprostol.

Miller, M.J.; Zhang, x.J.; Gu, x.A.; Clark, D.A. (Department of Pediatrics, Louisiana State University School of Medicine, New Orleans (USA))

1991-07-01

192

Determination of formic-acid and acetic acid concentrations formed during hydrothermal treatment of birch wood and its relation to colour, strength and hardness  

Microsoft Academic Search

Formation of benzyl esters from acetic and formic acids during heat treatment of birch at 160–200°C has been studied by gas chromatography. High concentrations of formic and acetic acids formed by the wood itself during hydrothermal treatment were found. The concentrations of acids increased with both treatment time and temperature. The maximum formic- and acetic acid concentrations found at 180°C

Bror Sundqvist; Olov Karlsson; Ulla Westermark

2006-01-01

193

Antimicrobial activity of lactic acid bacteria isolated from minced beef meat against some pathogenic bacteria  

Microsoft Academic Search

In this study we achieved to isolate and identify Lactic Acid Bacteria (LAB) from minced beef meat by using de Man Rogosa and Sharpe agar (MRS) medium. The influence of antimicrobial activities were obtained by using the agar well diffusion method (Muller Hinton Agar) against some members of gram positive and gram negative pathogenic bacteria involved ( Escherichia coli, Pseudomonas

M. A. H. Al-Allaf; A. M. M. Al-Rawi; A. T. Al-Mola

194

Metabolic Regulation of the Plant Hormone Indole-3-Acetic Acid, (Final Report).  

National Technical Information Service (NTIS)

The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research question...

J. D. Cohen

2009-01-01

195

Apical dominance and the levels of indole acetic acid in Phaseolus lateral buds  

Microsoft Academic Search

Combined gas chromatography-mass spectrometry procedures have been used to establish that the indole acetic acid levels of lateral buds from Phaseolus seedlings rise following removal of the shoot apex.

J. R. Hillman; V. B. Math; G. C. Medlow

1977-01-01

196

Methods of Synthesizing and Using Derivatives of (2-(2-Aminioethoxy)Ethoxy) Acetic Acid.  

National Technical Information Service (NTIS)

A synthetic reaction to produce (2-(2-aminoethoxy)ethoxy) acetic acid (AEEA) derivatives. This synthetic reaction does not require isolation and purification of intermediates. The AEEA derivatives can be used to synthesize high load polystyrene-polyethyle...

J. V. Aldrich V. Kumar

2005-01-01

197

Isobaric vapor–liquid equilibria for water + acetic acid + ( N-methyl pyrrolidone or N-methyl acetamide)  

Microsoft Academic Search

Isobaric vapor–liquid equilibria (VLE) data for acetic acid+N-methyl pyrrolidone, acetic acid+N-methyl acetamide, water+acetic acid+N-methyl pyrrolidone, and water+acetic acid+N-methyl acetamide systems have been measured at 101.33kPa using a recirculating still. The nonideality of the vapor phase caused by the association of the acetic acid has been corrected by the chemical theory and Hayden–O’Connell method. The experimental binary data have been correlated

Weixian Chang; Hui Wan; Guofeng Guan; Huqing Yao

2006-01-01

198

Complexation of chitosan with acetic acid according to Fourier transform Raman spectroscopy data  

NASA Astrophysics Data System (ADS)

The results of the interaction between the protonated chitosan (CHI) macromolecule and the acetate ion in dilute acetic acid solutions were studied by Fourier transform Raman spectroscopy and quantum-chemical modeling. The complexation of CHI with the acetate ion showed itself as the 934 cm-1 band in the Raman spectrum, which suggests the formation of [CHI+ · CH3COO-] type ion pairs. It was concluded that a comparative analysis of the integrated intensities of the Raman bands in the range 880-940 cm-1 makes it possible to judge about the relative content of hydrated acetate ions, CHI macromolecules of the [CHI+ · CH3COO-] complex, and acetic acid molecules not involved in CHI protonation.

Mikhailov, G. P.; Tuchkov, S. V.; Lazarev, V. V.; Kulish, E. I.

2014-06-01

199

Importance of lactic acid bacteria in Asian fermented foods  

PubMed Central

Lactic acid bacteria play important roles in various fermented foods in Asia. Besides being the main component in kimchi and other fermented foods, they are used to preserve edible food materials through fermentation of other raw-materials such as rice wine/beer, rice cakes, and fish by producing organic acids to control putrefactive microorganisms and pathogens. These bacteria also provide a selective environment favoring fermentative microorganisms and produce desirable flavors in various fermented foods. This paper discusses the role of lactic acid bacteria in various non-dairy fermented food products in Asia and their nutritional and physiological functions in the Asian diet.

2011-01-01

200

Modification of maize starch by thermal processing in glacial acetic acid  

Microsoft Academic Search

Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods were used to determine if corn starch–glacial acetic acid mixtures can be melted and thermally processed at reasonable temperatures. DSC studies showed that the melting temperature of dry starch was reduced from about 280 to 180°C in the presence of >30% acetic acid. Glass transition temperatures varied from 110 to 40°C

R. L Shogren

2000-01-01

201

ANTI-INFLAMMATORY ACTIVITY OF PHYCOCYANIN EXTRACT IN ACETIC ACID-INDUCED COLITIS IN RATS  

Microsoft Academic Search

The anti-inflammatory effect of c -phycocyanin extract was studied in acetic acid-induced colitis in rats. Phycocyanin (150, 200 and 300 mg kg?1p.o.) was administered 30 min before induction of colitis with enema of 1 ml of 4% acetic acid per rat. Twenty-four hours later myeloperoxidase (MPO) activity was determined as well as histopathological and ultrastructural studies were carried out in

RICARDO GONZÁLEZ; SANDRA RODRÍGUEZ; ADDYS GONZÁLEZ; DIADELIS REMIREZ; NELSON MERINO

1999-01-01

202

Polycarboxylic acids containing acetal functions: calcium sequestering compounds based on oxidized carbohydrates  

Microsoft Academic Search

A number of polycarboxylic acids containing acetal functions have been prepared by a two-step oxidation of carbohydrates.\\u000a Their calcium sequestering behavior is compared with that of a series of model polycarboxylic acids. It is found that calcium\\u000a sequestration by oxidized carbohydrates is less than that by corresponding ether polycarboxylates, since (a) acetal oxygens\\u000a have a lower coordinating power than ether

M. S. Nieuwenhuizen; A. P. G. Kieboom; H. van Bekkum

1983-01-01

203

Control of magnesia–alumina properties by acetic acid in sol–gel synthesis  

Microsoft Academic Search

Sol–gel synthesis was used to prepare oxides of aluminum and magnesium from mixtures of Al(O–s-Bu)3 and Mg(O–Et)2, with the atomic ratio of Al to Mg being 4. The hydrolysis and condensation reactions were controlled by acetic acid in the absence of added water; the ratio R of acetic acid to aluminum alkoxide (R=[CH3COOH]\\/[Al(O–s-Bu)3]) was varied from 1 to 6. The

Saloua Rezgui; Bruce C Gates

1997-01-01

204

Accelerated ripening of Dhakki dates by artificial means: ripening by acetic acid and sodium chloride  

Microsoft Academic Search

The effectiveness of sodium chloride and acetic acid for initiation\\/acceleration of the ripening of Dhakki dates has been investigated. Each treatment was applied individually and\\/or in combined form at different proportions varying from 0.25% to 3.5% and 0.25% to 2.5% for sodium chloride and acetic acid respectively. Dhakki dates at the Doka stage were immersed in treatment solutions for 5min

Shahzada A. Saleem; Ahmad K. Baloch; Musa Kaleem Baloch; Waqar A. Baloch; Abdul Ghaffoor

2005-01-01

205

Large prebiotic molecules in space: photo-physics of acetic acid and its isomers  

Microsoft Academic Search

An increasing number of large molecules have been positively identified in\\u000aspace. Many of these molecules are of biological interest and thus provide\\u000ainsight into prebiotic organic chemistry in the protoplanetary nebula. Among\\u000athese molecules, acetic acid is of particular importance due to its structural\\u000aproximity to glycine, the simplest amino acid. We compute electronic and\\u000avibrational properties of acetic

Fabrizio Puletti; Giuliano Malloci; Giacomo Mulas; Cesare Cecchi-Pestellini

2009-01-01

206

Chromoendoscopy of gastric adenoma using an acetic acid indigocarmine mixture  

PubMed Central

AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy. METHODS: A total of 54 lesions in 45 patients diagnosed as gastric adenoma by forceps biopsy were prospectively enrolled in this study and treated by endoscopic submucosal dissection (ESD) between January 2011 and January 2012. AIM-chromoendoscopy (AIM-CE) was performed followed by ESD. AIM solution was sprinkled and images were recorded every 30 s for 3 min. Clinical characteristics such as tumor size (< 2 cm, ? 2 cm), surface color in white light endoscopy (WLE) (whitish, normochromic or reddish), macroscopic appearance (flat or elevated, depressed), and reddish change in AIM-CE were selected as valuables. RESULTS: En bloc resection was achieved in all 54 cases, with curative resection of fifty two lesions (96.3%). Twenty three lesions (42.6%) were diagnosed as well-differentiated adenocarcinoma and the remaining 31 lesions (57.4%) were gastric adenoma. All adenocarcinoma lesions were well-differentiated tubular adenocarcinomas and were restricted within the mucosal layer. The sensitivity of reddish color change in AIM-CE is significantly higher than that in WLE (vs tumor size ? 2 cm, P = 0.016, vs normochromic or reddish surface color, P = 0.046, vs depressed macroscopic type, P = 0.0030). On the other hand, no significant differences were found in the specificity and accuracy. In univariate analysis, normochromic or reddish surface color in WLE (OR = 3.7, 95%CI: 1.2-12, P = 0.022) and reddish change in AIM-CE (OR = 14, 95%CI: 3.8-70, P < 0.001) were significantly related to diagnosis of early gastric cancer (EGC). In multivariate analysis, only reddish change in AIM-CE (OR = 11, 95%CI: 2.3-66, P = 0.0022) was a significant factor associated with diagnosis of EGC. CONCLUSION: AIM-CE may have potential for screening EGC in patients initially diagnosed as gastric adenoma by forceps biopsy.

Kono, Yoshiyasu; Takenaka, Ryuta; Kawahara, Yoshiro; Okada, Hiroyuki; Hori, Keisuke; Kawano, Seiji; Yamasaki, Yasushi; Takemoto, Koji; Miyake, Takayoshi; Fujiki, Shigeatsu; Yamamoto, Kazuhide

2014-01-01

207

Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria  

PubMed Central

Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 106 acetate-utilizing manganese-reducing cells cm?3 in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

2012-01-01

208

Iontophoretic enhancement of leuprolide acetate by fatty acids, limonene, and depilatory lotions through porcine epidermis.  

PubMed

The effect of chemical enhancers (e.g., fatty acids, limonene, depilatory lotions) and iontophoresis was investigated on the in vitro permeability of leuprolide acetate through porcine epidermis. Franz diffusion cells and Scepter iontophoretic power source were used for the percutaneous absorption studies. Anodal iontophoresis was performed at 0.2 mA/cm2 current density. Fatty acids used were palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3) acids. The passive and iontophoretic flux were significantly (p < 0.05) greater through fatty acids-treated porcine epidermis in comparison to the control (untreated epidermis) for leuprolide acetate. The passive and iontophoretic permeability of leuprolide acetate increased with increasing number of cis double bonds. Among the fatty acids tested, linolenic acid (C18:3) exhibited the maximum permeability of leuprolide acetate during passive (51.42 x 10(-4) cm/hr) and iontophoretic (318.98 x 10(-4) cm/hr) transport. The passive and iontophoretic flux of leuprolide acetate were significantly (p < 0.05) greater through the limonene and depilatory lotion treated epidermis in comparison to their respective control. In conclusion, iontophoresis in combination with chemical enhancers synergistically increased (p < 0.05) the in vitro permeability of leuprolide acetate through porcine epidermis. PMID:15581070

Rastogi, Sumeet K; Singh, Jagdish

2004-11-01

209

Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.  

PubMed

The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid. PMID:24206724

Majzoobi, Mahsa; Beparva, Paniz

2014-03-15

210

Antimutagenic and immuno-stimulatory properties of lactic acid bacteria  

Microsoft Academic Search

Statistically significant antigenotoxic activity was exerted by six of nine strains of lactic acid bacteria tested (Lactobacillus delbrueckii subsp. bulgaricus, Staphylococcus carnosus, Streptococcus thermophilus, L. rhamnosus, Enterococcus faecium and En. faecalis) against nitrovin and 2-aminofluorene in Salmonella typhimurium TA100 and TA97. The mutagenic activity of both mutagens was substantially decreased by viable bacteria; cells heated to 100°C for 15 min

L. Ebringer; M. Feren?ík; N. Lahitová; L. Ka?áni; D. Michálková

1995-01-01

211

The fraction of cells that resume growth after acetic acid addition is a strain-dependent parameter of acetic acid tolerance in Saccharomyces cerevisiae.  

PubMed

High acetic acid tolerance of Saccharomyces cerevisiae is a relevant phenotype in industrial biotechnology when using lignocellulosic hydrolysates as feedstock. A screening of 38 S. cerevisiae strains for tolerance to acetic acid revealed considerable differences, particularly with regard to the duration of the latency phase. To understand how this phenotype is quantitatively manifested, four strains exhibiting significant differences were studied in more detail. Our data show that the duration of the latency phase is primarily determined by the fraction of cells within the population that resume growth. Only this fraction contributed to the exponential growth observed after the latency phase, while all other cells persisted in a viable but non-proliferating state. A remarkable variation in the size of the fraction was observed among the tested strains differing by several orders of magnitude. In fact, only 11 out of 10(7)  cells of the industrial bioethanol production strain Ethanol Red resumed growth after exposure to 157 mM acetic acid at pH 4.5, while this fraction was 3.6 × 10(6) (out of 10(7)  cells) in the highly acetic acid tolerant isolate ATCC 96581. These strain-specific differences are genetically determined and represent a valuable starting point to identify genetic targets for future strain improvement. PMID:24645649

Swinnen, Steve; Fernández-Niño, Miguel; González-Ramos, Daniel; van Maris, Antonius J A; Nevoigt, Elke

2014-06-01

212

Genetics of the proteolytic system of lactic acid bacteria  

Microsoft Academic Search

The proteolytic system of lactic acid bacteria is of eminent importance for the rapid growth of these organisms in protein-rich media. The combined action of proteinases and peptidases provides the cell with small peptides and essential amino acids. The amino acids and peptides thus liberated have to be translocated across the cytoplasmic membrane. To that purpose, the cell contains specific

Jan Kok

1990-01-01

213

Conjugated linoleic acid production from linoleic acid by lactic acid bacteria  

Microsoft Academic Search

After screening 14 genera of lactic acid bacteria, Lactobacillus plantarum AKU 1009a was selected as a potential strain for CLA production from linoleic acid. Washed cells of L. plantarum with high levels of CLA production were obtained by cultivation in a nutrient medium with 0.06% (wt\\/vol) linoleic acid (cis-9,cis-12-octadecadienoic acid). Under the optimal reaction conditions with the free form of

Shigenobu Kishino; Jun Ogawa; Yoriko Omura; Kenji Matsumura; Sakayu Shimizu

2002-01-01

214

Photoproduction of H 2 from acetate by syntrophic cocultures of green sulfur bacteria and sulfur-reducing bacteria  

Microsoft Academic Search

The marine green sulfur bacterium Chlorobium vibrioforme strain 1930 produced H2 and elemental sulfur from sulfide or thiosulfate under N limitation in the light. H2 production depended on nitrogenase and occurred only in the absence of ammonia. Methionine sulfoximine, an inhibitor of glutamine synthetase, prevented the switch-off by ammonia. In defined syntrophic cocultures of the acetate-oxidizing, sulfur-reducing bacterium Desulfuromonas acetoxidans

Rolf Warthmann; Heribert Cypionka; Norbert Pfennig

1992-01-01

215

Synthesis and in vitro transdermal penetration enhancing activity of lactam N-acetic acid esters.  

PubMed

A homologous series of N-acetic acid esters of 2-pyrrolidinone and 2-piperidinone has been prepared and evaluated for its ability to enhance the skin content and flux of hydrocortisone 21-acetate in hairless mouse skin in vitro. Enhancement ratios (ER) were determined for flux (J), 24-hour diffusion cell receptor cell concentrations (Q24), and 24-h full-thickness mouse skin steroid content (SC) and compared to control values (no enhancer present). In addition, in an attempt to abrogate toxicity, these dermal penetration enhancers were designed to have the potential for biodegradation by dermal esterases. 2-Oxopyrrolidine-alpha acetic acid dodecyl ester (5) showed the highest enhancement ratios for J (ER 67.33) and Q24 (ER 180.66). 2-Oxopiperidine-alpha-acetic acid decyl ester (10) showed a high Q24 (ER 162.07) but a lower J (ER 12.67). 2-Oxopyrrolidine-alpha-acetic acid decyl ester (3) showed the highest enhancement ratio for SC (ER 8.7). The ER Q24 for 3, 5 and 10, as well as other lactam N-acetic acid esters in this work, were significantly higher than the ER found using Azone as enhancer. PMID:8683439

Michniak, B B; Player, M R; Sowell, J W

1996-02-01

216

Performance of dairy cows fed high levels of acetic acid or ethanol.  

PubMed

Ethanol and acetic acid are common end products from silages. The main objective of this study was to determine whether high concentrations of ethanol or acetic acid in total mixed ration would affect performance in dairy cows. Thirty mid-lactation Holstein cows were grouped in 10 blocks and fed one of the following diets for 7 wk: (1) control (33% Bermuda hay + 67% concentrates), (2) ethanol [control diet + 5% ethanol, dry matter (DM) basis], or (3) acetic acid (control diet + 5% acetic acid, DM basis). Ethanol and acetic acid were diluted in water (1:2) and sprayed onto total mixed rations twice daily before feeding. An equal amount of water was mixed with the control ration. To adapt animals to these treatments, cows were fed only half of the treatment dose during the first week of study. Cows fed ethanol yielded more milk (37.9 kg/d) than those fed the control (35.8 kg/d) or acetic acid (35.3 kg/d) diets, mainly due to the higher DM intake (DMI; 23.7, 22.2, and 21.6 kg/d, respectively). The significant diet × week interaction for DMI, mainly during wk 2 and 3 (when acetic acid reached the full dose), was related to the decrease in DMI observed for the acetic acid treatment. There was a diet × week interaction in excretion of milk energy per DMI during wk 2 and 3, due to cows fed acetic acid sustained milk yield despite lower DMI. Energy efficiency was similar across diets. Blood metabolites (glucose, insulin, nonesterified fatty acids, ethanol, and ?-glutamyl transferase activity) and sensory characteristics of milk were not affected by these treatments. Animal performance suggested similar energy value for the diet containing ethanol compared with other diets. Rumen conversion of ethanol to acetate and a concomitant increase in methane production might be a plausible explanation for the deviation of the predicted energy value based on the heat of combustion. Therefore, the loss of volatile compounds during the drying process in the laboratory should be considered when calculating energy content of fermented feedstuffs. PMID:23141834

Daniel, J L P; Amaral, R C; Sá Neto, A; Cabezas-Garcia, E H; Bispo, A W; Zopollatto, M; Cardoso, T L; Spoto, M H F; Santos, F A P; Nussio, L G

2013-01-01

217

Inhibition of phorbol myristate acetate and phytohemagglutinin stimulation of human lymphocytes by 13-cis-retinoic acid and ethyl etrinoate  

Microsoft Academic Search

Summary The retinol analogues 13-cis-retinoic acid and ethyl etrinoate inhibit the mitogenic activity of phorbol myristate acetate and phytohemagglutinin on human lymphocytes. This inhibitory effect is greater against the stimulation with phorbol myristate acetate than with phytohemagglutinin.

L. F. Skinnider; K. Giesbrecht

1981-01-01

218

Adsorptive Membranes vs. Resins for Acetic Acid Removal from Biomass Hydrolysates  

SciTech Connect

Acetic acid is a compound commonly found in hemicellulosic hydrolysates. This weak acid strongly influences the bioconversion of sugar containing hydrolysates. Previous investigators have used anion exchange resins for acetic acid removal from different hemicellulosic hydrolysates. In this study, the efficiency of an anion exchange membrane was compared to that of an anion exchange resin, for acetic acid removal from a DI water solution and an acidic hemicellulose hydrolysate pretreated using two different methods. Ion exchange membranes and resins have very different geometries. Here the performance of membranes and resins is compared using two dimensionless parameters, the relative mass throughput and chromatographic bed number. The relative mass throughput arises naturally from the Thomas solution for ion exchange. The results show that the membrane exhibit better performance in terms of capacity, and loss of the desired sugars. In addition acetic acid may be eluted at a higher concentration from the membrane thus leading to the possibility of recovery and re-use of the acetic acid.

Han, B.; Carvalho, W.; Canilha, L.; da Silva, S. S.; e Silva, J. B. A.; McMillan, J. D.; Wickramasinghe, S. R.

2006-01-01

219

Microbiological preservation of cucumbers for bulk storage using acetic acid and food preservatives.  

PubMed

Microbial growth did not occur when cucumbers were preserved without a thermal process by storage in solutions containing acetic acid, sodium benzoate, and calcium chloride to maintain tissue firmness. The concentrations of acetic acid and sodium benzoate required to ensure preservation were low enough so that stored cucumbers could be converted to the finished product without the need to wash out and discard excess acid or preservative. Since no thermal process was required, this method of preservation would be applicable for storing cucumbers in bulk containers. Acid tolerant pathogens died off in less than 24 h with the pH, acetic acid, and sodium benzoate concentrations required to assure the microbial stability of cucumbers stored at 30 degrees C. Potassium sorbate as a preservative in this application was not effective. Yeast growth was observed when sulfite was used as a preservative. PMID:19241560

Pérez-Díaz, I M; McFeeters, R F

2008-08-01

220

Conductometric simultaneous determination of acetic acid, monochloroacetic acid and trichloroacetic acid using orthogonal signal correction-partial least squares.  

PubMed

A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing technique used to remove the information unrelated to the target variables is studied. The calibration model was build using conductometric titrations data of 16 mixtures of three acids. The concentration matrix was designed by a orthogonal design. The root mean squares error of prediction (RMSEP) for acetic acid, monochloroacetic acid and trichloroacetic acid with and without OSC were 0.08, 0.30 and 0.08, and 0.15, 0.40 and 0.18, respectively. The results obtained by OSC-PLS are better than the PLS and this indicate the successful application of the OSC filter as a good preprocessing method in multivariate calibration methods. The proposed procedure allows the simultaneous determination of these acids, in the synthetic mixtures. PMID:16236436

Ghorbani, R; Ghasemi, J; Abdollahi, B

2006-04-17

221

Microwave Spectroscopy and Proton Transfer Dynamics in the Formic Acid-Acetic Acid Dimer  

NASA Astrophysics Data System (ADS)

The rotational spectrum of the doubly hydrogen-bonded {hetero} dimer formed between formic acid and acetic acid has been recorded between 4 and 18 GHz using a pulsed-nozzle Fourier transform microwave spectrometer. Each rigid-molecule rotational transition is split into four as a result of two concurrent tunnelling motions, one being proton transfer between the two acid molecules, and the other the torsion/rotation of the methyl group within the acetic acid. We present a full assignment of the spectrum for {J} = 1 to {J} = 7 for these four torsion/tunnelling states. Spectra have been observed for the main isotopic species, with deuterium substitution at the C of the formic acid and all 13C species in natural abundance, The observed transitions are fitted to within a few kilohertz using a molecule-fixed effective rotational Hamiltonian for the separate {A} and {E} vibrational species of the G12 permutation-inversion group which is applicable to this complex. To reduce the effects of internal angular momentum, a non-principal axis system is used throughout. Interpretation of the internal motion uses an internal-vibration and overall rotation scheme, and full sets of rotational and centrifugal distortion constants are determined. The proton tunnelling rates and the internal angular momentum of the methyl group in the {E} states is interpreted in terms of a dynamical model which involves coupled proton transfer and internal rotation. The resulting potential energy surface not only describes these internal motions, but can also explain the observed shifts in rotational constants between {A} and {E} species, and the deviations of the tunnelling frequencies from the expected 2:1 ratio. It also permits the determination of spectral constants free from the contamination effects of the internal dynamics. M.C.D. Tayler, B. Ouyang and B.J. Howard, J. Chem. Phys., {134}, 054316 (2011).

Howard, B. J.; Steer, E.; Page, F.; Tayler, M.; Ouyang, B.; Leung, H. O.; Marshall, M. D.; Muenter, J. S.

2012-06-01

222

Radiofrequency Thermal Ablation: Increase in Lesion Diameter with Continuous Acetic Acid Infusion  

SciTech Connect

Purpose. To evaluate the influence of continuous infusion of acetic acid 50% during radiofrequency ablation (RFA) on the size of the thermal lesion produced. Methods. Radiofrequency (RF) was applied to excised bovine liver by using an expandable needle electrode with 10 retractable tines (LeVeen Needle Electrode, RadioTherapeutics, Sunnyvale, CA) connected to a commercially available RF generator (RF 2000, RadioTherapeutics, Sunnyvale, CA). Experiments were performed using three different treatment modalities: RF only (n = 15), RF with continuous saline 0.9% infusion (n = 15), and RF with continuous acetic acid 50% infusion (n = 15). RF duration, power output, tissue impedance, and time to a rapid rise in impedance were recorded. The ablated lesions were evaluated both macroscopically and histologically. Results. The ablated lesions appeared as spherical or ellipsoid, well-demarcated pale areas with a surrounding brown rim with both RF only and RF plus saline 0.9% infusion. In contrast, thermolesions generated with RF in combination with acetic acid 50% infusion were irregular in shape and the central portion was jelly-like. Mean diameter of the coagulation necrosis was 22.3 {+-} 2.1 mm (RF only), 29.2 {+-} 4.8 mm (RF + saline 0.9%) and 30.7 {+-} 5.7 mm (RF + acetic acid 50%), with a significant increase in the RF plus saline 0.9% and RF plus acetic acid 50% groups compared with RF alone. Time to a rapid rise in impedance was significantly prolonged in the RF plus saline 0.9% and RF plus acetic acid 50% groups compared with RF alone. Conclusions. A combination of RF plus acetic acid 50% infusion is able to generate larger thermolesions than RF only or RF combined with saline 0.9% infusion.

Lubienski, Andreas [Ruprecht-Karls-University Heidelberg, Department of Diagnostic Radiology (Germany)], E-mail: lubienski@radiologie.uni-luebeck.de; Duex, Markus [Hospital Northwest Frankfurt, Department of Radiology (Germany); Lubienski, Katrin; Grenacher, Lars; Kauffmann, Guenter [Ruprecht-Karls-University Heidelberg, Department of Diagnostic Radiology (Germany)

2005-12-15

223

A case report of a chemical burn due to the misuse of glacial acetic acid.  

PubMed

As young and elastic skin is what everyone dreams of, various measures have been implemented including chemical, laser resurfacing and dermabrasion to improve the condition of ageing skin. However, the high cost of these procedures prevents the poor from having access to treatment. Glacial acetic acid is widely used as a substitute for chemical peeling because it is readily easily available and affordable. However, its use can result in a number of serious complications. A 28-year-old female patient was admitted to our hospital with deep second-degree chemical burns on her face caused by the application of a mixture of glacial acetic acid and flour for chemical peeling. During a 6-month follow-up, hypertrophic scarring developed on the both nasolabial folds despite scar management. Glacial acetic acid is a concentrated form of the organic acid, which gives vinegar its sour taste and pungent smell, and it is also an important reagent during the production of organic compounds. Unfortunately, misleading information regarding the use of glacial acetic acid for chemical peeling is causing serious chemical burns. Furthermore, there is high possibility of a poor prognosis, which includes inflammation, hypertrophic scar formation and pigmentation associated with its misuse. Therefore, we report a case of facial chemical burning, due to the misuse of glacial acetic acid, and hope that this report leads to a better understanding regarding the use of this reagent. PMID:20708991

Yoo, Jun-Ho; Roh, Si-Gyun; Lee, Nae-Ho; Yang, Kyung-Moo; Moon, Ji-Hyun

2010-12-01

224

Metabolite Profiles of Lactic Acid Bacteria in Grass Silage?  

PubMed Central

The metabolite production of lactic acid bacteria (LAB) on silage was investigated. The aim was to compare the production of antifungal metabolites in silage with the production in liquid cultures previously studied in our laboratory. The following metabolites were found to be present at elevated concentrations in silos inoculated with LAB strains: 3-hydroxydecanoic acid, 2-hydroxy-4-methylpentanoic acid, benzoic acid, catechol, hydrocinnamic acid, salicylic acid, 3-phenyllactic acid, 4-hydroxybenzoic acid, (trans, trans)-3,4-dihydroxycyclohexane-1-carboxylic acid, p-hydrocoumaric acid, vanillic acid, azelaic acid, hydroferulic acid, p-coumaric acid, hydrocaffeic acid, ferulic acid, and caffeic acid. Among these metabolites, the antifungal compounds 3-phenyllactic acid and 3-hydroxydecanoic acid were previously isolated in our laboratory from liquid cultures of the same LAB strains by bioassay-guided fractionation. It was concluded that other metabolites, e.g., p-hydrocoumaric acid, hydroferulic acid, and p-coumaric acid, were released from the grass by the added LAB strains. The antifungal activities of the identified metabolites in 100 mM lactic acid were investigated. The MICs against Pichia anomala, Penicillium roqueforti, and Aspergillus fumigatus were determined, and 3-hydroxydecanoic acid showed the lowest MIC (0.1 mg ml?1 for two of the three test organisms).

Broberg, Anders; Jacobsson, Karin; Strom, Katrin; Schnurer, Johan

2007-01-01

225

Effects of humic acids on the growth of bacteria  

NASA Astrophysics Data System (ADS)

The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

2010-03-01

226

Exogenous treatment with indole-3-acetic acid and salicylic acid alleviates cadmium toxicity in wheat seedlings.  

PubMed

The seedlings of wheat were grown in the presence of CdCl2 (500 or 1000 ?M Cd), were applied with 500 ?M of indole-3-acetic acid (IAA) or 500 ?M salicylic acid (SA) as seed soaking and were sampled at 56 days after sowing. The plants exposed to Cd exhibited a substantial decline in growth, pigment content, relative water content (RWC) activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) and leaf structure. However, pretreatment with IAA or SA mitigated the stress generated by Cd and markedly improved the aforesaid parameters. The Cd increased proline content, electrolyte leakage and plant Cd content. However, the IAA or SA treatment attenuated the adverse effects of Cd on these attributes. The results showed that pretreatment with IAA or SA enhanced the antioxidant defense activities in Cd stressed wheat, thus alleviating Cd induced oxidative damage and enhancing Cd tolerance and leaf anatomy. PMID:23684274

Agami, Ramadan A; Mohamed, Gamal F

2013-08-01

227

A laboratory study of the effect of acetic acid vapor on atmospheric copper corrosion  

SciTech Connect

A study was made of the copper corrosion rate and corrosion products originated by the action of acetic acid vapor at 100% relative humidity. Copper plates were exposed to an acetic acid contaminated atmosphere for a period of 21 days. Five acetic vapor concentration levels were used. The copper corrosion rate was in the range of 1 to 23 mg/dm{sup 2} day. The corrosion-product layers were characterized using electrochemical, X-ray powder diffraction, Fourier transform infrared spectrometry, and scanning electron microscopy techniques. Thermal and calorimetric studies were also performed. Some of the compounds identified were cuprite (Cu{sub 2}O), copper acetate hydrate [Cu(CH{sub 3}COO){sub 2}{center_dot}2H{sub 2}O], and copper hydroxide acetate [Cu{sub 4}(OH)(CH{sub 3}COO){sub 7}{center_dot}2H{sub 2}O]. This last compound was also characterized. The thickness of the patina layers was 4 to 8 nm for amorphous cuprite, 11 to 48 nm for cuprite, and 225 nm for copper acetate. The patina, in which the cementation process of different corrosion-product layers plays an important role, is formed by the reaction of acetic vapor with copper through porous cuprite paths.

Lopez-Delgado, A.; Cano, E.; Bastidas, J.M.; Lopez, F.A. [Centro Nacional de Investigaciones Metalurgicas, Madrid (Spain)

1998-12-01

228

Psychrotrophic, lactic acid-producing bacteria from anoxic waters in Ace Lake, Antarctica; Carnobacterium funditum sp. nov. and Carnobacterium alterfunditum sp. nov  

Microsoft Academic Search

Heterofermentative, lactic acid-producing, gram-positive, motile bacteria were isolated from the waters of Ace Lake, Antarctica. All strains produced virtually only l(+)lactic acid from d(+)glucose. d(-)ribose was fermented to lactic, acetic, and formic acids, and ethanol. Cell walls contained meso-diaminopimaleic acid. The strains did not grow at 30°C and were psychrotrophic. Whole cells contained 18:1cis 9 as a major component of

P. D. Franzmann; P. Höpfl; N. Weiss; B. J. Tindall

1991-01-01

229

Large prebiotic molecules in space: photophysics of acetic acid and its isomers  

NASA Astrophysics Data System (ADS)

An increasing number of large molecules have been positively identified in space. Many of these molecules are of biological interest and thus provide insight into prebiotic organic chemistry in the protoplanetary nebula. Among these molecules, acetic acid is of particular importance due to its structural proximity to glycine, the simplest amino acid. We compute electronic and vibrational properties of acetic acid and its isomers, methyl formate and glycolaldehyde, using density functional theory. From the computed photoabsorption cross-sections, we obtain the corresponding photoabsorption rates for solar radiation at 1au and find them in good agreement with previous estimates. We also discuss glycolaldehyde diffuse emission in Sgr B2(N), as opposite to emissions from methyl formate and acetic acid that appear to be concentrated in the compact region Sgr B2(N-LMH).

Puletti, Fabrizio; Malloci, Giuliano; Mulas, Giacomo; Cecchi-Pestellini, Cesare

2010-03-01

230

Purification and Partial Characterization of a Glucan Containing Indole-3-acetic Acid 1  

PubMed Central

The “bound auxin” of Zea mays, first described by Berger and Avery (Amer. J. Bot. 1944; 31: 199-203) has been purified and partially characterized. It is an indole-3-acetic acid-containing, high molecular weight, lipophilic cellulosicglucan. The indole-3-acetic acid is in ester linkage as evidenced by indoleacetamide formation upon ammonolysis. The glucan is of variable chain length and comprises, in general, 35 to 50 per cent of the dry weight of the compound. The glucosidic residues are ? 1 ? 4 linked and are hydrolyzed by cellulase. Mild acid hydrolysis produces cellobiose and cellotriose. Other components, as yet unidentified, of the compound are described.

Piskornik, Zdzislaw; Bandurski, Robert S.

1972-01-01

231

Heterogeneous photocatalytic synthesis of methane from acetic acid: new Kolbe reaction pathway  

Microsoft Academic Search

The heterogeneous photocatalytic decomposition of acetic acid on n-type TiOâ to yield almost exclusively methane and carbon dioxide is reported. Probable reaction mechanisms are discussed. It is assumed that the TiOâ powder acts in a dual function causing the photooxidation of acetate and the reduction of intermediately formed methyl radicals. This property is not found at metal electrodes under usual

Bernhard Kraeutler; Allen J. Bard

1978-01-01

232

Hydrogen production by catalytic steam reforming of acetic acid, a model compound of biomass pyrolysis liquids  

Microsoft Academic Search

An environmentally friendly and cost-competitive way of producing hydrogen is the catalytic steam reforming of biomass pyrolysis liquids, known as bio-oil, which can be separated into two fractions: ligninic and aqueous. Acetic acid has been identified as one of the major organic acids present in the latter, and catalytic steam reforming has been studied for this model compound. Three different

F. Bimbela; M. Oliva; J. Ruiz; L. García; J. Arauzo

2007-01-01

233

Volatile acetic acid and formaldehyde emission from plywood treated with boron compound  

Microsoft Academic Search

The effects of plywood on formaldehyde and volatile acetic acid emissions treated with borax and boric acid were investigated. The treated plywood samples were manufactured by using two different methods; each veneer was first impregnated by a dipping method before the first group of plywood was manufactured. The second group of plywood panels was produced by adding preservatives (borax, boric

S. Colak; G. Colakoglu

2004-01-01

234

Extraction equilibria of acetic and propionic acids from dilute aqueous solution by several solvents  

SciTech Connect

Extraction equilibria of acetic acid and propionic acid with hexane solutions of trioctyl amine, trioctyl phosphine oxide, and tributyl phosphate were studied. The species formed in the systems were estimated, and the distribution coefficients and the equilibrium constants for these species were evaluated.s

Fahim, M.A. (Univ. of United Arab Emirates, Al-Ain (United Arab Emirates))

1992-10-01

235

Environmental Risk Limits for Ethylene Diamine Tetra Acetic acid (EDTA)  

Microsoft Academic Search

In this report maximum permissible concentration (MPC) and negligible\\u000aconcentration (NC) in water are derived for Ethylene Diamine Tetra Acetic\\u000aacid (EDTA; CAS No. 64-02-8, EINECS No. 200-573-9), based on the EU\\u000arisk assessment report for this compound. The Maximum Permissible\\u000aConcentration (MPC) for the water compartment is 2.2 mg\\/l, and the\\u000aNegligible Concentration (NC) is 0.022 mg\\/l. Calculation of

Kalf DF; Hoop van den MAGT; Rila JP; Posthuma C; Traas TP

2007-01-01

236

Coproduction of acetic acid and electricity by application of microbial fuel cell technology to vinegar fermentation.  

PubMed

The coproduction of a useful material and electricity via a novel application of microbial fuel cell (MFC) technology to oxidative fermentation was investigated. We focused on vinegar production, i.e., acetic acid fermentation, as an initial and model useful material that can be produced by oxidative fermentation in combination with MFC technology. The coproduction of acetic acid and electricity by applying MFC technology was successfully demonstrated by the simultaneous progress of acetic acid fermentation and electricity generation through a series of repeated batch fermentations. Although the production rate of acetic acid was very small, it increased with the number of repeated batch fermentations that were conducted. We obtained nearly identical (73.1%) or larger (89.9%) acetic acid yields than that typically achieved by aerated fermentation (75.8%). The open-cycle voltages measured before and after fermentation increased with the total fermentation time and reached a maximum value of 0.521 V prior to the third batch fermentation. The maximum current and power densities measured in this study (19.1 ?A/cm² and 2.47 ?W/cm², respectively) were obtained after the second batch fermentation. PMID:23518569

Tanino, Takanori; Nara, Youhei; Tsujiguchi, Takuya; Ohshima, Takayuki

2013-08-01

237

Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose  

PubMed Central

Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v) we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP). To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA) such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L.

Macias, Miguel Macias; Manso, Antonio Garcia; Orellana, Carlos Javier Garcia; Velasco, Horacio Manuel Gonzalez; Caballero, Ramon Gallardo; Chamizo, Juan Carlos Peguero

2013-01-01

238

Bacteriocins from Lactic Acid Bacteria: Production, Purification, and Food Applications  

Microsoft Academic Search

In fermented foods, lactic acid bacteria (LAB) display numerous antimicrobial activities. This is mainly due to the production of organic acids, but also of other compounds, such as bacteriocins and antifungal peptides. Several bacteriocins with industrial potential have been purified and characterized. The kinetics of bacteriocin production by LAB in relation to process factors have been studied in detail through

Luc De Vuyst; Frédéric Leroy

2007-01-01

239

Genesis of Acetate and Methane by Gut Bacteria of Nutritionally Diverse Termites  

Microsoft Academic Search

The evolution of different feeding guilds in termites is paralleled by differences in the activity of their gut microbiota. In wood-feeding termites, carbon dioxide-reducing acetogenic bacteria were found to generally outprocess carbon dioxide-reducing methanogenic bacteria for reductant (presumably hydrogen) generated during microbial fermentation in the hindgut. By contrast, acetogenesis from hydrogen and carbon dioxide was of little significance in fungus-growing

Alain Brauman; Matthew D. Kane; Marc Labat; John A. Breznak

1992-01-01

240

Microarray-based transcriptome of Listeria monocytogenes adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.  

PubMed

Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies. PMID:22913877

Tessema, Girum Tadesse; Møretrø, Trond; Snipen, Lars; Heir, Even; Holck, Askild; Naterstad, Kristine; Axelsson, Lars

2012-09-01

241

Lantibiotics produced by lactic acid bacteria: structure, function and applications  

Microsoft Academic Search

Lantibiotics are a diverse group of heavily modified antimicrobial and\\/or signalling peptides produced by a wide range of bacteria, including a variety of lactic acid bacteria. Based on their diverse structures and mode of action, at least six separate lantibiotic subgroups can be suggested, but all subgroups are characterized by significant post-translational modifications, which include the formation of (ß-methyl)lanthionines, among

Denis Twomey; R. P. Ross; Maire Ryan; Billy Meaney; C. Hill

2002-01-01

242

[Determination of five halogenated acetic acids in water using ion chromatography].  

PubMed

The five halogenated acetic acids (HAAs), monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), trichloro acetic acid (TCAA), monobromoacetic acid (MBAA), dibromoacetic acid (DBAA), were separated on an IonPac AS19 column specially designed for oxyhalides, and the separating conditions were optimized. DCAA and nitrite were separated by controlling the temperature. TCAA and sulfate were well separated rapidly by the concentration gradient of mobile phase. The interfering of carbonate (bicarbonate) was eliminated by the method of neutralization vacuum exhausting gas. The experimental results showed that the five HAAs, nitrite, bromide, nitrate, sulfate, etc. can be separated and detected simultaneously, and the detection limits of the DCAA and TCAA were 2.50 microg/L and 3.75 microg/L respectively, and the linearity ranges were from 10.0 to 2000.0 microg/L with the correlation coefficients of 0.999. The method is satisfied for the determination of drinking water. PMID:18438039

Gui, Jianye; Zhang, Lin

2008-01-01

243

Remediation of acid mine drainage with sulfate reducing bacteria  

SciTech Connect

Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

Hauri, J.F.; Schaider, L.A. [Assumption College, Worcester, MA (USA)

2009-02-15

244

Use of acetic and citric acids to control Salmonella Typhimurium in tahini (sesame paste).  

PubMed

Since tahini and its products have been linked to Salmonella illness outbreaks and product recalls in recent years, this study assessed the ability of Salmonella Typhimurium to survive or grow in commercial tahini and when hydrated (10% w/v in water), treated with 0.1%-0.5% acetic or citric acids, and stored at 37, 21 and 10 °C for 28 d. S. Typhimurium survived in commercial tahini up to 28 d but was reduced in numbers from 1.7 to 3.3 log10 CFU/ml. However, in the moist or hydrated tahini, significant growth of S. Typhimurium occurred at the tested temperatures. Acetic and citric acids at ?0.5% reduced S. Typhimurium by 2.7-4.8 log10 CFU/ml and 2.5-3.8 log10 CFU/ml, respectively, in commercial tahini at 28 d. In hydrated tahini the organic acids were more effective. S. Typhimurium cells were not detected in the presence of 0.5% acetic acid after 7 d or with 0.5% citric acid after 21 d at the tested temperatures. The ability of S. Typhimurium to grow or survive in commercial tahini and products containing hydrated tahini may contribute to salmonellosis outbreaks; however, use of acetic and citric acids in ready-to-eat foods prepared from tahini can significantly minimize the risk associated with this pathogen. PMID:24929724

Al-Nabulsi, Anas A; Olaimat, Amin N; Osaili, Tareq M; Shaker, Reyad R; Zein Elabedeen, Noor; Jaradat, Ziad W; Abushelaibi, Aisha; Holley, Richard A

2014-09-01

245

Inhibition of microbial xylitol production by acetic acid and its relation with fermentative parameters.  

PubMed

Precipitated sugarcane bagasse hemicellulosic hydrolysate containing acetic acid was fermented by Candida guilliermondii FTI20037 under different operational conditions (pH 4.0 and 7.0, three aeration rates). At pH 7.0 and kLa of 10 (0.75 vvm) and 22.5/h (3.0 vvm) the acetic acid had not been consumed until the end of the fermentations, whereas at the same pH and kLa of 35/h (4.5 vvm) the acid was rapidly consumed and acetic acid inhibition was not important. On the other hand, fermentations at an initial pH of 4.0 and kLa of 22.5 and 35/h required less time for the acid uptake than fermentations at kLa of 10/h. The acetic acid assimilation by the yeast indicates the ability of this strain to ferment in partially detoxified medium, making possible the utilization of the sugarcane bagasse hydrolysate in this bio-process. The effects on xylitol yield and production are reported. PMID:10849838

Morita, T A; Silva, S S

2000-01-01

246

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients.  

PubMed

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance of the method in drug delivery systems are discussed. PMID:8541297

Clerc, S; Barenholz, Y

1995-12-13

247

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients  

Microsoft Academic Search

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance

Stéphane Clerc; Yechezkel Barenholz

1995-01-01

248

A Possible Source of Error in the Chemical Detection of Indolyl Acetic Acid in Plants  

Microsoft Academic Search

DURING investigations on the growth substances of fruits of cacao and bananas (Musa spp.), it was of interest to find that a substance was present in seeded bananas which gave a pink colour with ferric chloride\\/perchloric acid or p-dimethyl amino-benz-aldehyde\\/hydrochloric acid, corresponding to the RF of indolyl acetic acid and to the zone of bioassay using the wheat coleoptile straight-growth

R. Nichols

1958-01-01

249

Characteristics of isolated lactic acid bacteria and their effectiveness to improve stylo (Stylosanthes guianensis Sw.) silage quality at various temperatures.  

PubMed

Two lactic acid bacteria (LAB) strains, Pediococcus pentosaceus SC1 and Lactobacillus paraplantarum SC2 isolated from king grass silage, were characterized and their effectiveness to improve the silage fermentation quality of stylo (Stylosanthes guianensis Sw.) was studied. Strain SC1 was able to grow at a high temperature of 45°C, while SC2 did not. SC2 normally grew at a low pH of 4.0, while SC1 could not. These two strains and a commercial inoculant of LAB (L. plantarum, LP) were used as additives to stylo silage preparation at various temperatures (20°C, 30°C and 40°C). All LAB inoculants significantly (P < 0.05) reduced the pH value and ammonia-N content, and increased the ratio of lactic acid to acetic acid and quality score compared with the control. In addition, inoculating LAB strains markedly (P < 0.05) reduced butyric acid content at the temperatures of 30°C and 40°C. Compared to SC2 and LP strains, strain SC1 was the most effective for improving stylo silage quality at 20°C, indicated by the increase in lactic acid, ratio of lactic acid to acetic acid and quality score. At 30°C and 40°C, there were no significant differences among SC1, SC2 and LP treatments in pH values, contents of acetic acid, butyric acid and ammonia-N (P > 0.05). PMID:22339693

Liu, Qinhua; Chen, Mingxia; Zhang, Jianguo; Shi, Shangli; Cai, Yimin

2012-02-01

250

An Explanation of the Inhibition of Root Growth Caused by Indole-3-Acetic Acid 1  

PubMed Central

Low concentrations of indole-3-acetic acid inhibit the growth of pea root sections by inducing the formation of the growth regulator, ethylene gas. Ethylene is produced within 15 to 30 minutes after indole-3-acetic acid is applied and roots begin to swell immediately after they are exposed to the gas. Carbon dioxide competitively inhibits ethylene action in roots, impedes their geotropic response, and partially reinstates auxin inhibited growth. It is concluded that ethylene participates in the geotropic response of roots, but not that of stems. Images

Chadwick, Arthur V.; Burg, Stanley P.

1967-01-01

251

Metal-organic frameworks of vanadium as catalysts for conversion of methane to acetic acid.  

PubMed

A catalytic system combining the high activity of homogeneous catalysts and the ease of use of heterogeneous catalysts for methane activation is reported. The vanadium-containing metal-organic frameworks (MOFs) MIL-47 and MOF-48 are found to have high catalytic activity and chemical stability. They convert methane selectively to acetic acid with 70% yield (490 TON) based on K(2)S(2)O(8) as an oxidant. Isotopic labeling experiments showed that two methane molecules are converted to the produced acetic acid. The MOF catalysts are reusable and remain catalytically active for several recycling steps without losing their crystalline structures. PMID:21766786

Phan, Anh; Czaja, Alexander U; Gándara, Felipe; Knobler, Carolyn B; Yaghi, Omar M

2011-08-15

252

Mechanisms leading to oligomers and SOA through aqueous photooxidation: insights from OH radical oxidation of acetic acid and methylglyoxal  

NASA Astrophysics Data System (ADS)

Previous experiments have demonstrated that the aqueous OH radical oxidation of methylglyoxal produces low volatility products including pyruvate, oxalate and oligomers. These products are found predominantly in the particle phase in the atmosphere, suggesting that methylglyoxal is a precursor of secondary organic aerosol (SOA). Acetic acid plays a central role in the aqueous oxidation of methylglyoxal and it is a ubiquitous product of gas phase photochemistry, making it a potential "aqueous" SOA precursor in its own right. However, the fate of acetic acid upon aqueous-phase oxidation is not well understood. In this research, acetic acid (20 ?M-10 mM) was oxidized by OH radicals, and pyruvic acid and methylglyoxal experimental samples were analyzed using new analytical methods, in order to better understand the formation of SOA from acetic acid and methylglyoxal. Glyoxylic, glycolic, and oxalic acids formed from acetic acid and OH radicals. In contrast to the aqueous OH radical oxidation of methylglyoxal, the aqueous OH radical oxidation of acetic acid did not produce succinic acid and oligomers. This suggests that the methylgloxal-derived oligomers do not form through the acid catalyzed esterification pathway proposed previously. Using results from these experiments, radical mechanisms responsible for oligomer formation from methylglyoxal oxidation in clouds and wet aerosols are proposed. The importance of acetic acid/acetate as an SOA precursor is also discussed. We hypothesize that this and similar chemistry is central to the daytime formation of oligomers in wet aerosols.

Tan, Y.; Lim, Y. B.; Altieri, K. E.; Seitzinger, S. P.; Turpin, B. J.

2012-01-01

253

Purification of bacteriocins of lactic acid bacteria: problems and pointers.  

PubMed

Bacteriocins of lactic acid bacteria have been widely studied in recent years. However, there are relatively few studies that describes their biochemical structure. This study may be due to the many challenges associated with the purification of these antimicrobial peptides. This review focuses on the purification procedures used with bacteriocins of lactic acid bacteria and conveys some of the problems associated with this process as well as some of the lessons learned. An improvement in the efficiency of the purification process should contribute significantly to research at the understanding of the biochemical nature of bacteriocins. PMID:9029252

Carolissen-Mackay, V; Arendse, G; Hastings, J W

1997-01-01

254

Formic and acetic acid over the central Amazon region, Brazil 1. Dry season  

SciTech Connect

We have determined the atmospheric concentrations of formic and acetic acid in the gas phase, in aerosols, and in rain during the dry season (July--August 1985) in the Amazonia region of Brazil. At ground level the average concentrations of gas phase formic and acetic acid were 1.6 +- 0.6 and 2.2 +- 1.0 ppb, respectively. The diurnal behavior of both acids at ground level and their vertical distribution in the forest canopy point to the existence of vegetative sources as well as to production by chemical reactions in the atmosphere. Dry deposition of the gaseous acids appears to be a major sink. The concentrations of formic and acetic acid in the gas phase were about 2 orders of magnitude higher than concentrations of the corresponding species in the atmospheric aerosol. About 50--60%/sub 0/ of the aerosol (total) formate and acetate were in the size fraction below 1.0 ..mu..m diameter.

Andreae, M.O.; Talbot, R.W.; Andreae, T.W.; Harriss, R.C.

1988-02-20

255

Influence of 5-Methyltryptophan-Resistant Bradyrhizobium japonicum on Soybean Root Nodule Indole-3-Acetic Acid Content †  

PubMed Central

Bradyrhizobium japonicum mutants resistant to 5-methyltryptophan were isolated. Some of these mutants were found to accumulate indole-3-acetic acid (IAA) and tryptophan in culture. In greenhouse studies, nodules from control plants inoculated with wild-type bradyrhizobia contained 0.04, 0.10, and 0.58 ?g of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules?1, respectively. Nodules from plants inoculated with 5-methyltryptophan-resistant bradyrhizobia contained 0.94, 1.30, and 10.6 ?g of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules?1, respectively. This manyfold increase in nodule IAA content indicates that the Bradyrhizobium inoculum can have a considerable influence on the endogenous IAA level of the nodule. Further, these data imply that much of the IAA that accumulated in the high-IAA-containing nodules was of bacterial rather than plant origin. These high-IAA-producing 5-methyltryptophan-resistant bacteria were poor symbiotic nitrogen fixers. Plants inoculated with these bacteria had a lower nodule mass and fixed less nitrogen per gram of nodule than did plants inoculated with wild-type bacteria.

Hunter, William J.

1987-01-01

256

Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor  

SciTech Connect

Acetate was produced from whey lactose in batch and fed-batch fermentations using co-immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45-L column reactor, with liquid circulated through a 5-L stirred-tank fermentor. Industrial-grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentations were used to keep lactate concentration low and to adapt cells to high-concentration acetate. The final acetate concentration obtained in the fed-batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous-bed reactor volume. The cells isolated from the fibrous-bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate-tolerant strains occurred. This cocultured fermentation process could be used to produce a low-cost acetate deicer from whey permeate and acid whey.

Huang, Y.; Yang, S.T. [Ohio State Univ., Columbus, OH (United States). Dept. of Chemical Engineering] [Ohio State Univ., Columbus, OH (United States). Dept. of Chemical Engineering

1998-11-20

257

Enzymological studies of one-carbon reactions in the pathway of acetate utilization by methanogenic bacteria  

SciTech Connect

Several enzymes in the pathway of acetate conversion to methane and carbon dioxide have been purified from Methanosarcina thermophila. The mechanisms of these enzymes are under investigation utilizing biochemical, biophysical and molecular genetic approaches. Acetate kinase and phosphotransacetylase catalyzes the activation of acetate to acetyl-CoA. The primary structure of these enzymes will be determined through cloning and sequencing of the genes. Two protein components of the CO dehydrogenase complex are under investigations. The metal centers of each component have been characterized using EPR. Cloning and sequencing of the genes for the two subunits of each component is in progress. Results indicate that the Ni/Fe-S component cleaves the C-C and C-S bonds of acetyl-CoA followed by oxidation of the carbonyl group to carbon dioxide and transfer of the methyl group to the Co/Fe-S component. The enzymes and cofactors involved in transfer of the methyl group from the Co/Fe-S component to coenzyme M will be purified and characterized. Ferredoxin is an electron acceptor for the Ni/Fe-S component and also serves to reductively reactivate methylreductase which catalyzes the demethylation of methyl coenzyme M to methane. This ferredoxin is being characterized utilizing EPR and RR spectroscopic methods to determine the properties of the Fe-S centers. Genes encoding this and other ferredoxins have been cloned and sequenced to determine the primary structures. Carbonic anhydrase is being purified and characterized to determine the function of this enzyme in the pathway.

Ferry, J.G.

1991-01-01

258

Enzymological studies of one-carbon reactions in the pathway of acetate utilization by methanogenic bacteria  

SciTech Connect

Several enzymes in the pathway of acetate conversion to methane and carbon dioxide have been purified from Methanosarcina thermophila. The mechanisms of these enzymes are under investigation utilizing biochemical, biophysical and molecular genetic approaches. Acetate kinase and phosphotransacetylase catalyzes the activation of acetate to acetyl-CoA. The primary structure of these enzymes will be determined through cloning and sequencing of the genes. Two protein components of the CO dehydrogenase complex are under investigations. The metal centers of each component have been characterized using EPR. Cloning and sequencing of the genes for the two subunits of each component is in progress. Results indicate that the Ni/Fe-S component cleaves the C-C and C-S bonds of acetyl-CoA followed by oxidation of the carbonyl group to carbon dioxide and transfer of the methyl group to the Co/Fe-S component. The enzymes and cofactors involved in transfer of the methyl group from the Co/Fe-S component to coenzyme M will be purified and characterized. Ferredoxin is an electron acceptor for the Ni/Fe-S component and also serves to reductively reactivate methylreductase which catalyzes the demethylation of methyl coenzyme M to methane. This ferredoxin is being characterized utilizing EPR and RR spectroscopic methods to determine the properties of the Fe-S centers. Genes encoding this and other ferredoxins have been cloned and sequenced to determine the primary structures. Carbonic anhydrase is being purified and characterized to determine the function of this enzyme in the pathway.

Ferry, J.G.

1991-12-31

259

Lipidomic profiling of Saccharomyces cerevisiae and Zygosaccharomyces bailii reveals critical changes in lipid composition in response to acetic acid stress.  

PubMed

When using microorganisms as cell factories in the production of bio-based fuels or chemicals from lignocellulosic hydrolysate, inhibitory concentrations of acetic acid, released from the biomass, reduce the production rate. The undissociated form of acetic acid enters the cell by passive diffusion across the lipid bilayer, mediating toxic effects inside the cell. In order to elucidate a possible link between lipid composition and acetic acid stress, the present study presents detailed lipidomic profiling of the major lipid species found in the plasma membrane, including glycerophospholipids, sphingolipids and sterols, in Saccharomyces cerevisiae (CEN.PK 113_7D) and Zygosaccharomyces bailii (CBS7555) cultured with acetic acid. Detailed physiological characterization of the response of the two yeasts to acetic acid has also been performed in aerobic batch cultivations using bioreactors. Physiological characterization revealed, as expected, that Z. bailii is more tolerant to acetic acid than S. cerevisiae. Z. bailii grew at acetic acid concentrations above 24 g L(-1), while limited growth of S. cerevisiae was observed after 11 h when cultured with only 12 g L(-1) acetic acid. Detailed lipidomic profiling using electrospray ionization, multiple-reaction-monitoring mass spectrometry (ESI-MRM-MS) showed remarkable changes in the glycerophospholipid composition of Z. bailii, including an increase in saturated glycerophospholipids and considerable increases in complex sphingolipids in both S. cerevisiae (IPC 6.2×, MIPC 9.1×, M(IP)2C 2.2×) and Z. bailii (IPC 4.9×, MIPC 2.7×, M(IP)2C 2.7×), when cultured with acetic acid. In addition, the basal level of complex sphingolipids was significantly higher in Z. bailii than in S. cerevisiae, further emphasizing the proposed link between lipid saturation, high sphingolipid levels and acetic acid tolerance. The results also suggest that acetic acid tolerance is associated with the ability of a given strain to generate large rearrangements in its lipid profile. PMID:24023914

Lindberg, Lina; Santos, Aline Xs; Riezman, Howard; Olsson, Lisbeth; Bettiga, Maurizio

2013-01-01

260

Transporters and receptors for short-chain fatty acids as the molecular link between colonic bacteria and the host.  

PubMed

The mutually beneficial relationship between colonic bacteria and the host has been recognized but the molecular aspects of the relationship remain poorly understood. Dietary fiber is critical to this relationship. The short-chain fatty acids acetate, propionate and butyrate, generated by bacterial fermentation of dietary fiber, serve as messengers between colonic bacteria and the host. The beneficial effects of these bacterial metabolites in colon include, but are not limited to, suppression of inflammation and prevention of cancer. Recent studies have identified the plasma membrane transporter SLC5A8 and the cell-surface receptors GPR109A and GPR43 as essential for the biologic effects of short-chain fatty acids in colon. These three proteins coded by the host genome provide the molecular link between colonic bacteria and the host. PMID:23978504

Ganapathy, Vadivel; Thangaraju, Muthusamy; Prasad, Puttur D; Martin, Pamela M; Singh, Nagendra

2013-12-01

261

Combined sorption\\/transport of sodium dodecyl sulfate and hydrochloric acid in a blend of cellulose acetate butyrate with cellulose acetate hydrogen phthalate  

Microsoft Academic Search

The transport of hydrochloric acid (0.001–0.1 M) and sodium dodecyl sulfate (0.001–0.1 M) has been measured through a membrane consisting of a blend of cellulose acetate butyrate and cellulose acetate hydrogen phthalate. The cellulose derivative blend is suggested to suffer an alteration in the degree of hydrophobicity when in equilibrium with sodium dodecyl sulfate (SDS) through hemimicelle formation. An increase

Artur J. M. Valente; Hugh D. Burrows; Alexandre Ya. Polishchuk; Maria G. Miguel; Victor M. M. Lobo

2004-01-01

262

Production of eicosapentaenoic acid from marine bacteria.  

PubMed

A marine bacterium, judged as a new species close to Shewanella putrefaciens, was isolated from the intestinal contents of the Pacific mackerel. The isolated strain SCRC-2378 produced eicosapentaenoic acid (EPA) as the sole polyunsaturated fatty acid, which amounted to 24-40% of the total fatty acid in the cell, which corresponded to 2% of dry cell weight. Under the optimal growth conditions (pH 7.0, 20 degrees C, and grown aerobically for 12-18 h), the yield of SCRC-2738 reached 15 g of dry cells/L or 2 x 10(10) viable cells/mL. EPA existed as phospholipid and was found in the sn-2 position of phosphatidylethanolamine and phosphatidylglycerol. The 38 kbp (1,000 base pairs) genome DNA fragment was cloned from SCRC-2738 and expressed in Escherichia coli, which resulted in the production of EPA. The nucleotide sequence of the 38 kbp DNA fragment was determined. The DNA fragment contains eight open reading frames, and three of them possess homology with enzymes involved in fatty acid synthesis. Thus, it may be possible that these EPA biosynthesis genes are applied for EPA production in yeasts or higher plants, and offer a new method for EPA synthesis as new foods containing EPA. PMID:8729138

Yazawa, K

1996-03-01

263

Calibration and intercomparison of acetic acid measurements using proton transfer reaction mass spectrometry (PTR-MS)  

NASA Astrophysics Data System (ADS)

Acetic acid is one of the most abundant organic acids in the ambient atmosphere, with maximum mixing ratios reaching into the tens of parts per billion by volume (ppbv) range. The identities and associated magnitudes of the major sources and sinks for acetic acid are poorly characterized, due in part to the limitation in available measurement techniques. This paper demonstrates that Proton Transfer Reaction Mass Spectrometry (PTR-MS) can reliably quantify acetic acid vapor in ambient air. Three different PTR-MS configurations were calibrated at low ppbv mixing ratios using permeation tubes, which yielded calibration factors between 7.0 and 10.9 normalized counts per second per ppbv (ncps ppbv-1) at a drift tube field strength of 132 townsend (Td). Detection limits ranged from 0.06 to 0.32 ppbv with dwell times of 5 s. These calibration factors showed negligible humidity dependence. Using the experimentally determined calibration factors, PTR-MS measurements of acetic acid during the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) campaign were validated against results obtained using Mist Chambers coupled with Ion Chromatography (MC/IC). An orthogonal least squares linear regression of paired data yielded a slope of 1.14 ± 0.06 (2?), an intercept of 0.049 ± 20 (2?) ppbv, and an R2 of 0.78. The median mixing ratio of acetic acid on Appledore Island, ME during the ICARTT campaign was 0.530 ± 0.025 ppbv with a minimum of 0.075 ± 0.004 ppbv, and a maximum of 3.555 ± 0.171 ppbv.

Haase, K. B.; Keene, W. C.; Pszenny, A. A. P.; Mayne, H. R.; Talbot, R. W.; Sive, B. C.

2012-07-01

264

[Concentrations and acidity contributions of acetate and formate in precipitation at 14 stations of China].  

PubMed

To investigate the concentrations of organic acids in precipitation in China and their contributions to the total acidity of precipitation, samples were taken at 14 stations of regional representativeness in 2007 and analyzed for acetate and formate using ion chromatography. In this paper, data of acetate and formate in precipitation at 14 stations are presented, wet depositions of these organic acids are calculated, and contributions of them to the total free acidity (TFA) of precipitation are estimated. Based on the measurements, the mean concentrations of formate at different stations were in the range of 0.96-3.43 micromol/L, and those of acetate in the range of 0-5.13 micromol/L, close to the levels at remote sites in other countries and at the lower ends of concentration ranges from previous measurements in China. Comparisons indicate that the concentrations of the organic acids at remote sites are lower than those at sites in the vicinity of urban areas. The annual wet depositions of formate and acetate were estimated to be in the ranges of 0.38-4.18 mmol/(m2 x a) and 0.06-5.87 mmol/(m2 x a), respectively, with larger depositions in southern China and smaller depositions in northern China. The relative contributions of the two organic acids to the TFA of precipitation were estimated to be in the range of 0.02%-51.6%, with an overall average of 2.95%. This suggests that although acid rain in China is mainly caused by emissions of sulfur and nitrogen oxides, organic acids can significantly contribute to the acidification of precipitation in some regions and during some periods, hence need to be included in observational studies of acid rain. PMID:20527162

He, Xiao-huan; Xu, Xiao-bin; Yu, Xiao-lan; Tang, Jie

2010-04-01

265

Variations in the energy metabolism of biotechnologically relevant heterofermentative lactic acid bacteria during growth on sugars and organic acids.  

PubMed

Heterofermentative lactic acid bacteria (LAB) such as Leuconostoc, Oenococcus, and Lactobacillus strains ferment pentoses by the phosphoketolase pathway. The extra NAD(P)H, which is produced during growth on hexoses, is transferred to acetyl-CoA, yielding ethanol. Ethanol fermentation represents the limiting step in hexose fermentation, therefore, part of the extra NAD(P)H is used to produce erythritol and glycerol. Fructose, pyruvate, citrate, and O2 can be used in addition as external electron acceptors for NAD(P)H reoxidation. Use of the external acceptors increases the growth rate of the bacteria. The bacteria are also able to ferment organic acids like malate, pyruvate, and citrate. Malolactic fermentation generates a proton potential by substrate transport. Pyruvate fermentation sustains growth by pyruvate disproportionation involving pyruvate dehydrogenase. Citrate is fermented in the presence of an additional electron donor to acetate and lactate. Thus, heterofermentative LAB are able to use a variety of unusual fermentation reactions in addition to classical heterofermentation. Most of the reactions are significant for food biotechnology/microbiology. PMID:16826375

Zaunmüller, T; Eichert, M; Richter, H; Unden, G

2006-09-01

266

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

Microsoft Academic Search

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M +

B. R. DeMark; P. D. Klein

1981-01-01

267

Indole3-acetic acid increases glutamine utilization by high peroxidase activity-presenting leukocytes  

Microsoft Academic Search

Indole-3-acetic acid (IAA) is toxic for human tumor cells and in association with horseradish peroxidase (HRP) can be used as a new prodrug\\/enzyme combination for targeted cancer therapy. The toxic effect of IAA on neutrophils, macrophages and lymphocytes is associated with cell peroxidase activity, which is high in neutrophils and low in lymphocytes. The effect of IAA on glucose and

Mariza P De Melo; Tania C Pithon-Curi; Rui Curi

2004-01-01

268

Seasonal Allergic Rhinitic and Normal Subjects Respond Differentially to Nasal Provocation with Acetic Acid Vapor  

Microsoft Academic Search

Individuals with seasonal allergic rhinitis (SAR) show a more marked nasal obstructive response (increases in nasal airways resistance or NAR) after provocation with chlorine gas (Cl2) than do nonrhinitic (NR) controls. We were interested in learning whether similar differential respon- siveness was apparent after provocation with acetic acid vapor. Sixteen nonsmoking, nonasth- matic subjects, aged 21-63 yr, equally divided by

Dennis shusterman; Alice Tarun; Mary Alice Murphy; John Morris

2005-01-01

269

New N- and O-arylations with phenylboronic acids and cupric acetate  

Microsoft Academic Search

A new method of arylating N?H and O?H containing compounds at room temperature with phenylboronic acids and cupric acetate in the presence of a tertiary amine promoter is described. Substrates include phenols, amines, anilines, amides, imides, ureas, carbamates, and sulfonamides.

Dominic M. T Chan; Kevin L Monaco; Ru-Ping Wang; Michael P Winters

1998-01-01

270

Kinetics of hydroxyapatite dissolution in acetic, lactic, and phosphoric acid solutions  

Microsoft Academic Search

Summary The present study was undertaken in an attempt to relate the kinetics of hydroxyapatite dissolution to solution parameters, under experimental conditions relevant to the dental caries process. Thus, the dissolution of hydroxyapatite was studied in acetic, lactic, and dilute phosphoric acid solutions having initial pH values from 4 to 6. Rates of dissolution and the corresponding degree of saturation

H. C. Margolis; E. C. Moreno

1992-01-01

271

Divergent effects of flavone acetic acid on established versus developing tumour blood flow  

Microsoft Academic Search

Flavone Acetic Acid (FAA) exerts much of its effect by reducing tumour blood flow. Previous studies on FAA-induced changes in blood flow have used established tumours with a functional microvasculature. Using radioactive Xenon(133Xe) clearance to monitor local blood flow we show that the effects of FAA are dependent on the presence of this functional microvasculature with no evidence that FAA

V Mahadevan; IR Hart

1991-01-01

272

Karplus-type relationship for quadrupole coupling constants and asymmetry parameters for substituted acetic acids  

SciTech Connect

The deuterium quadrupole coupling constant for the methyl group in acetic acid dimer was calculated as a function of the torsion angle about the carbon-carbon bond. The results show that when a deuteron approaches either of the negatively charged oxygen atoms, the quadrupole coupling constant for the deuteron is reduced by as much as 4.2 kHz. Both the calculated quadrupole coupling constant, e/sup 2/q/sub zz/Q/h, and asymmetry parameter, eta, are fitted with a Karplus-type equation: e/sup 2/q/sub zz/Q/h = A - 0.5491 cos theta - 1.7859 cos 2theta; eta = 0.0491 + 0.0058 cos theta - 0.0081 cos 2theta. Adiabatic demagnetization in the laboratory frame spectroscopy at 77 K for (4-chlorophenyl)(2,2-/sup 2/H/sub 2/)acetic acid showed two inequivalent deuteron sites that, on the basis of deuterium double transitions, are demonstrated to be due to two deuterium sites bound to the same carbon atom. The solid-state structure of (4-chlorophenyl)acetic acid was determined by single-crystal X-ray diffraction. The ADLF and structural data for (4-chlorophenyl)(2,2-/sup 2/H/sub 2/) acetic acid were used to obtain a preliminary value for the A parameter as 170.767 kHz.

Jackisch, M.A.; Jarrett, W.L.; Guo, K.; Fronczek, F.R.; Butler, L.G.

1988-01-20

273

Effects of Trimetazidine on Acetic Acid-Induced Colitis in Female Swiss Rats  

Microsoft Academic Search

Induction of colitis by acetic acid (A A) in the rat is widely used experimental model of inflammatory bowel disease (IBD) and ulcerations. AA as an irritant induces colitis involving infiltration of colonic mucosa with neutrophils and increased production of inflammatory mediators, such as hydrogen peroxide (H 2 O 2 ), nitric oxide (NO), myeloperoxidase activity (MPO), and tumor necrosis

Filiz Kuralay; Co?kun Yildiz; Omer Ozutemiz; Huray Islekel; Sezer Caliskan; Basak Bingol; Sermin Ozkal

2003-01-01

274

Selection of tropical lactic acid bacteria for enhancing the quality of maize silage.  

PubMed

The objective of this study was to select lactic acid bacteria (LAB) strains isolated from silage and assess their effect on the quality of maize silage. The LAB strains were inoculated into aqueous extract obtained from maize to evaluate their production of metabolites and pH reduction. The ability to inhibit the pathogenic and silage-spoilage microorganisms' growth was evaluated. Nine LAB strains that showed the best results were assessed in polyvinyl chloride experimental silos. The inoculation of the LAB strains influenced the concentration of lactic and acetic acids and the diversity of Listeria. The inoculation of silages with Lactobacillus buchneri (UFLA SLM11 and UFLA SLM103 strains) resulted in silages with greater LAB populations and improvements after aerobic exposure. The UFLA SLM11 and SLM103 strains identified as L. buchneri showed to be promising in the treatment of maize silage. PMID:24119815

Santos, A O; Ávila, C L S; Schwan, R F

2013-12-01

275

Amino Acid Transport Systems in Biotechnologically Relevant Bacteria  

Microsoft Academic Search

Besides metabolic pathways and regulatory networks, transport reactions are also pivotal for understanding\\u000a amino acid metabolism and production in bacteria. Apart from substrate uptake, this refers to product (amino\\u000a acid) excretion as well as product re-uptake. Both the mechanistic (kinetic and energetic) as well as structural\\u000a properties of these transport systems are relevant for understanding their significance and for providing

Kay Marin; Reinhard Krämer

276

Two-peptide bacteriocins produced by lactic acid bacteria  

Microsoft Academic Search

Bacteriocins from lactic acid bacteria are ribosomally produced peptides (usually 30–60 amino acids) that display potent antimicrobial activity against certain other Gram-positive organisms. They function by disruption of the membrane of their targets, mediated in at least some cases by interaction of the peptide with a chiral receptor molecule (e.g., lipid II or sugar PTS proteins). Some bacteriocins are unmodified

Sylvie Garneau; Nathaniel I Martin; John C Vederas

2002-01-01

277

Exopolysaccharides from lactic acid bacteria: perspectives and challenges  

Microsoft Academic Search

Some lactic acid bacteria (LAB) secrete a polysaccharide polymer. This extracellular polysaccharide, or ‘exopolysaccharide’ (EPS), is economically important because it can impart functional effects to foods and confer beneficial health effects. LAB have a ‘Generally Recognized As Safe’ (GRAS) classification and are likely candidates for the production of functional EPSs. Current challenges are to improve the productivity of EPSs from

Alan D. Welman; Ian S. Maddox

2003-01-01

278

Taxonomy and physiology of probiotic lactic acid bacteria  

Microsoft Academic Search

The current taxonomy of probiotic lactic acid bacteria is reviewed with special focus on the genera Lactobacillus, Bifidobacterium and Enterococcus. The physiology and taxonomic position of species and strains of these genera were investigated by phenotypic and genomic methods. In total, 176 strains, including the type strains, have been included. Phenotypic methods applied were based on biochemical, enzymatical and physiological

Günter Klein; Alexander Pack; Christine Bonaparte; Gerhard Reuter

1998-01-01

279

Glycerol metabolism and bitterness producing lactic acid bacteria in cidermaking  

Microsoft Academic Search

Several lactic acid bacteria were isolated from bitter tasting ciders in which glycerol was partially removed. The degradation of glycerol via glycerol dehydratase pathway was found in 22 out of 67 isolates. The confirmation of glycerol degradation by this pathway was twofold: showing their glycerol dehydratase activity and detecting the presence of the corresponding gene by a PCR method. 1,3-propanediol

G. Garai-Ibabe; I. Ibarburu; I. Berregi; O. Claisse; A. Lonvaud-Funel; A. Irastorza; M. T. Dueñas

2008-01-01

280

Modification of azo dyes by lactic acid bacteria  

Microsoft Academic Search

Aim: The ability of Lactobacillus casei and Lactobacillus paracasei to modify the azo dye, tartrazine, was recently documented as the result of the investigation on red coloured spoilage in acidified cucumbers. Fourteen other lactic acid bacteria (LAB) were screened for their capability to modify the food colouring tartrazine and other azo dyes of relevance for the textile industry. Methods and

I. M. Pérez-Díaz; R. F. McFeeters

2009-01-01

281

Systems solutions by lactic acid bacteria: from paradigms to practice  

PubMed Central

Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications.

2011-01-01

282

Heterologous production of bacteriocins by lactic acid bacteria  

Microsoft Academic Search

Over the last two decades, bacteriocins produced by lactic acid bacteria (LAB) have been the subject of considerable research and industrial interest due to their potential as food biopreservatives. The development of heterologous expression systems for such antimicrobial compounds may offer a number of advantages over native systems, such as facilitating the control of bacteriocin gene expression or achieving higher

J. M. Rodr??guez; M. I. Mart??nez; N. Horn; H. M. Dodd

2003-01-01

283

Polyphasic characterization of the lactic acid bacteria in kefir  

Microsoft Academic Search

The lactic acid bacteria of kefir were isolated and characterized using phenotypical, biochemical, and genotypical methods. Polyphasic analyses of results permitted the identification of the microflora to the strain level. The genus Lactobacillus was represented by the species Lb. kefir and Lb. kefiranofaciens. Both subspecies of Lactococcus lactis (lactis and cremoris) were isolated. Leuconostoc mesenteroides subsp. cremoris was also found.The

Isabelle Mainville; Normand Robert; Byong Lee; Edward R. Farnworth

2006-01-01

284

The use of static and dynamic physical property measurements to infer structural properties of associated liquids: Acetic acid–water  

Microsoft Academic Search

The anomalies which occur in most static and dynamic physical property measurements on solutions of water in acetic acid can be used with critical analysis to infer associative molecular structures. The anomalies indicate significant structural changes. Proton magnetic resonance chemical shifts for acetic acid–water solutions show a significant structural change occurring in the region of equal molar concentration. Literature values

Robert W. Sims; M. Robert Willicott III; R. R. Inners

1979-01-01

285

The use of static and dynamic physical property measurements to infer structural properties of associated liquids: Acetic acid-water  

Microsoft Academic Search

The anomalies which occur in most static and dynamic physical property measurements on solutions of water in acetic acid can be used with critical analysis to infer associative molecular structures. The anomalies indicate significant structural changes. Proton magnetic resonance chemical shifts for acetic acid-water solutions show a significant structural change occurring in the region of equal molar concentration. Literature values

Robert W. Sims; M. Robert Willicott III; R. R. Inners

1979-01-01

286

Computer aided design of reactive distillation processes for the treatment of waste waters polluted with acetic acid  

Microsoft Academic Search

A theoretical study of reactive distillation processes to remove acetic acid from its 30wt% aqueous solution by esterification with n-butanol is presented. Two different column structures were identified rendering theoretically close to 100 percent conversion of acetic acid. A model capable of precisely predicting the potential phase split is used. Total costs for the new processes are estimated and compared

Jignesh Gangadwala; G. Radulescu; Achim Kienle; K. Sundmacher

2007-01-01

287

Stimulation of fatty acid synthesis by 4?-phorbol-12-myristate-13-acetate in isolated rat hepatocytes  

Microsoft Academic Search

The tumor-promoting agent 4?-phorbol-12-myristate-13-acetate (TPA) is shown to be a potent stimulator of fatty acid synthesis\\u000a in isolated rat hepatocytes. The maximal effect of TPA is seen at 10?6 M, and the concentration for half-maximal effect is ca. 10?8 M. Stimulation of fatty acid synthesis by TPA is shown not to require the presence of extracellular Ca++. TPA produces a

Takahide Nomura; Masakatsu Tachibana; Hiroko Nomura; Yasumichi Hagino

1986-01-01

288

Interaction of ethylene with indole-3-acetic acid in regulation of rooting in pea cuttings  

Microsoft Academic Search

Cuttings of pea (Pisum sativum L. cv Marma) were treated with 1-aminocyclopropane-l-carboxylic acid (ACC). This treatment caused increased ethylene production and reduction of root formation. The effect of 0.1 mM ACC on the level of endogenous indole-3-acetic acid (IAA) in the rooting zone and in the shoot apex was analyzed by gas chromatography-single ion monitoring mass spectrometry or by high

A.-C. Nordstrom; L. Eliasson

1993-01-01

289

One carbon metabolism in anaerobic bacteria: organic acid and methane production. Final technical report  

SciTech Connect

Organic acids (i.e acetate and butyrate) and methane are respectively important as a chemical commodity and a fuel source for industry. Both of these products can be generated via bacterial fermentation of single carbon compounds (i.e, H/sub 2//CO/sub 2/, HCOOH, CO CH/sub 3/OH) derived from syngas or the pyrolysis of either coals-peats or renewable biomass. This research aims to understand the pathways and regulation of one carbon metabolism in acidogenic and methanogenic bacteria by detailed physiological and biochemical studies. These investigations will characterize and compare formate, methanol, H/sub 2//CO/sub 2/, CO, and acetate metabolism of Methanosarcina barkeri with that of Butyribacterium methylotrophicum. The research will focus on: elucidation of the function of formate dehydrogenase and carbon monoxide dehydrogenase; the catabolic routes and biochemical mechanisms for transformation of single carbon compounds and acetate; and, the regulation of single carbon metabolism during growth on multiple C/sub 1/ substrates or on multicarbon substrates. 8 refs.

Zeikus, J.G.

1985-01-01

290

Cellulose esterification with fatty acids and acetic anhydride in lithium chloride\\/ N,N -dimethylacetamide medium  

Microsoft Academic Search

Homogeneous esterification of cellulose with saturated fatty acids (n-octanoic to n-octadecanoic) was accomplished with acetic anhydride co-reactant in lithium chloride\\/N,N-dimethylacetamide (LiCl\\/DMAc) medium. Cellulose mixed triesters (CMT) were obtained after 5 h at 130°C with an average of\\u000a 2.2 acetyl groups and 0.8 fatty substituents per anhydroglucose unit. A mixed acetic-fatty anhydride, formed in situ, accounts for the grafting of the

C. Vaca-Garcia; S. Thiebaud; M. E. Borredon; G. Gozzelino

1998-01-01

291

In vaginal fluid, bacteria associated with bacterial vaginosis can be suppressed with lactic acid but not hydrogen peroxide  

PubMed Central

Background Hydrogen peroxide (H2O2) produced by vaginal lactobacilli is generally believed to protect against bacteria associated with bacterial vaginosis (BV), and strains of lactobacilli that can produce H2O2 are being developed as vaginal probiotics. However, evidence that led to this belief was based in part on non-physiological conditions, antioxidant-free aerobic conditions selected to maximize both production and microbicidal activity of H2O2. Here we used conditions more like those in vivo to compare the effects of physiologically plausible concentrations of H2O2 and lactic acid on a broad range of BV-associated bacteria and vaginal lactobacilli. Methods Anaerobic cultures of seventeen species of BV-associated bacteria and four species of vaginal lactobacilli were exposed to H2O2, lactic acid, or acetic acid at pH 7.0 and pH 4.5. After two hours, the remaining viable bacteria were enumerated by growth on agar media plates. The effect of vaginal fluid (VF) on the microbicidal activities of H2O2 and lactic acid was also measured. Results Physiological concentrations of H2O2 (< 100 ?M) failed to inactivate any of the BV-associated bacteria tested, even in the presence of human myeloperoxidase (MPO) that increases the microbicidal activity of H2O2. At 10 mM, H2O2 inactivated all four species of vaginal lactobacilli but only one of seventeen species of BV-associated bacteria. Moreover, the addition of just 1% vaginal fluid (VF) blocked the microbicidal activity of 1 M H2O2. In contrast, lactic acid at physiological concentrations (55-111 mM) and pH (4.5) inactivated all the BV-associated bacteria tested, and had no detectable effect on the vaginal lactobacilli. Also, the addition of 10% VF did not block the microbicidal activity of lactic acid. Conclusions Under optimal, anaerobic growth conditions, physiological concentrations of lactic acid inactivated BV-associated bacteria without affecting vaginal lactobacilli, whereas physiological concentrations of H2O2 produced no detectable inactivation of either BV-associated bacteria or vaginal lactobacilli. Moreover, at very high concentrations, H2O2 was more toxic to vaginal lactobacilli than to BV-associated bacteria. On the basis of these in vitro observations, we conclude that lactic acid, not H2O2, is likely to suppress BV-associated bacteria in vivo.

2011-01-01

292

Surface Binding of Aflatoxin B1 by Lactic Acid Bacteria  

PubMed Central

Specific lactic acid bacterial strains remove toxins from liquid media by physical binding. The stability of the aflatoxin B1 complexes formed with 12 bacterial strains in both viable and nonviable (heat- or acid-treated) forms was assessed by repetitive aqueous extraction. By the fifth extraction, up to 71% of the total aflatoxin B1 remained bound. Nonviable bacteria retained the highest amount of aflatoxin B1. Lactobacillus rhamnosus strain GG (ATCC 53103) and L. rhamnosus strain LC-705 (DSM 7061) removed aflatoxin B1 from solution most efficiently and were selected for further study. The accessibility of bound aflatoxin B1 to an antibody in an indirect competitive inhibition enzyme-linked immunosorbent assay suggests that surface components of these bacteria are involved in binding. Further evidence is the recovery of around 90% of the bound aflatoxin from the bacteria by solvent extraction. Autoclaving and sonication did not release any detectable aflatoxin B1. Variation in temperature (4 to 37°C) and pH (2 to 10) did not have any significant effect on the amount of aflatoxin B1 released. Binding of aflatoxin B1 appears to be predominantly extracellular for viable and heat-treated bacteria. Acid treatment may permit intracellular binding. In all cases, binding is of a reversible nature, but the stability of the complexes formed depends on strain, treatment, and environmental conditions.

Haskard, Carolyn A.; El-Nezami, Hani S.; Kankaanpaa, Pasi E.; Salminen, Seppo; Ahokas, Jorma T.

2001-01-01

293

Enhanced biofuel production through coupled acetic acid and xylose consumption by engineered yeast.  

PubMed

The anticipation for substituting conventional fossil fuels with cellulosic biofuels is growing in the face of increasing demand for energy and rising concerns of greenhouse gas emissions. However, commercial production of cellulosic biofuel has been hampered by inefficient fermentation of xylose and the toxicity of acetic acid, which constitute substantial portions of cellulosic biomass. Here we use a redox balancing strategy to enable efficient xylose fermentation and simultaneous in situ detoxification of cellulosic feedstocks. By combining a nicotinamide adenine dinucleotide (NADH)-consuming acetate consumption pathway and an NADH-producing xylose utilization pathway, engineered yeast converts cellulosic sugars and toxic levels of acetate together into ethanol under anaerobic conditions. The results demonstrate a breakthrough in making efficient use of carbon compounds in cellulosic biomass and present an innovative strategy for metabolic engineering whereby an undesirable redox state can be exploited to drive desirable metabolic reactions, even improving productivity and yield. PMID:24105024

Wei, Na; Quarterman, Josh; Kim, Soo Rin; Cate, Jamie H D; Jin, Yong-Su

2013-01-01

294

Formic and acetic acid over the central Amazon region, Brazil. I - Dry season  

NASA Technical Reports Server (NTRS)

The concentrations of formic and acetic acids in the gas phase, atmospheric aerosol, and rainwater samples collected in Amazonia at ground level and in the atmosphere during the Amazon Boundary Layer Experiment in July/August 1985 were analyzed by ion exchange chromatography. The diurnal behavior of both acids at ground level and their vertical distribution in the forest canopy point to the existence of vegetative sources as well as to production by chemical reactions in the atmosphere. The concentrations of formic and acetic acids in the gas phase were about 2 orders of magnitude higher than the corresponding concentrations in the atmospheric aerosol. In rainwater, the total formate and acetate represented about one half of the anion equivalents, in contrast to less than 10 percent of the soluble anionic equivalents contributed by these acids in the atmospheric aerosol. The observed levels of these ions in rainwater are considered to be the result of a combination of chemical reactions in hydrometeors and the scavenging of the gaseous acids by cloud droplets.

Andreae, M. O.; Andreae, T. W.; Talbot, R. W.; Harriss, R. C.

1988-01-01

295

Carriers for abscisic acid and indole-3-acetic acid in primary roots: their regional localisation and thermodynamic driving forces  

Microsoft Academic Search

A carrier for the uptake of abscisic acid (ABA) is present in the tips and elongating zones of primary roots of both leguminous (runner bean, French bean, pea) and non-leguminous (sunflower, maize) seedlings. No ABA carrier was present in more mature root regions. For indole-3-acetic acid both carrier-mediated uptake and a 2,3,5-triiodobenzoate-sensitive efflux component are present in growing and in

M. C. Astle; P. H. Rubery

1983-01-01

296

Observation of SERS of picolinic acid and nicotinic acid using cellulose acetate films doped with Ag fine particles  

NASA Astrophysics Data System (ADS)

Surface enhanced Raman (SER) spectra of picolinic acid and nicotinic acid were observed using cellulose acetate (CA) films doped with Ag fine particles. The spectra obtained match those reported for silver colloids though some differences in SER band intensity were observed. The ease of preparation and handling of the CA film method renders it more useful than the colloid method for the observation of SER spectra.

Imai, Yoshika; Kurokawa, Yoichi; Hara, Masaru; Fukushima, Michiko

1997-10-01

297

Molecular Biology and Genetics of the Acetate-Utilizing Methanogenic Bacteria  

SciTech Connect

Methane biosynthesis by the Methanosarcina species, in contrast to other methanogens, occurs from the full range of methanogenic substrates that include acetate, methanol, tri-methyl, di-methyl, and methyl-amine, methyl-sulfides, and in limited instances, H2/CO2. The Methanosarcina are also versatile in their ability to adapt and grow in habitats of varying osmolarity ranging from fresh water environments, marine environments, and to hyper saline environments (ca to 1.2 M NaCl). To facilitate studies that address the biochemistry, molecular biology and physiology of these organisms, we have constructed a whole-genome microarray to identify classes of differentially expressed genes in M. mazei strain Goe1. We propose to further identify and examine how genes and their proteins involved in the synthesis and transport of osmolytes in the cell are regulated. These compounds include N-epsilon-acetyl-beta-lysine, alpha-glutamate, betaine, and potassium whose levels within the cell are modulated in order to provide appropriate osmotic balance. We will identify differentially expressed genes involved in hydrogen and carbon dioxide sequestration since M. mazei strain Goe1 is currently the only practical model for such study. Finally, we will explore the essential roles of two metals, molybdate and tungstate, in methanogen regulation and metabolism of these environmentally essential organsims. The above studies will advance our general understanding of how methanogens respond to their environmental signals, and adapt by adjusting their physiology to thrive in changing anaerobic habitats whether natural or man-made.

Robert P. Gunsalus

2003-07-21

298

Acetate-utilizing bacteria at an oxic-anoxic interface in the Baltic Sea.  

PubMed

Pelagic redoxclines represent chemical gradients of elevated microbial activities. While chemolithoautotrophic microorganisms in these systems are well known as catalysts of major biogeochemical cycles, comparable knowledge on heterotrophic organisms is scarce. Thus, in this study, identity and biogeochemical involvement of active heterotrophs were investigated in stimulation experiments and activity measurements based on samples collected from pelagic redoxclines of the central Baltic Sea in 2005 and 2009. In the 2009 samples, (13)C-acetate 16S rRNA stable isotope probing (16S rRNA-SIP) identified gammaproteobacteria affiliated with Colwellia sp. and Neptunomonas sp. in addition to epsilonproteobacteria related to Arcobacter spp. as active heterotrophs at the oxic-anoxic interface layer. Incubations from sulfidic waters were dominated by two phylogenetic subgroups of Arcobacter. In the 2005 samples, organics, manganese(IV), and iron(III) were added to the sulfidic waters, followed by the determination of metal reduction and identification of the stimulated organisms. Here, the same Arcobacter and Colwellia subgroups were stimulated as in 2009, with Arcobacter predominating in samples, in which manganese(IV) reduction was highest. Our results offer new insights into the heterotrophic bacterial assemblage of Baltic Sea pelagic redoxclines and suggest Arcobacter spp. as a heterotroph with presumed relevance also for manganese cycling. PMID:23521397

Berg, Carlo; Beckmann, Sabrina; Jost, Günter; Labrenz, Matthias; Jürgens, Klaus

2013-08-01

299

Conversion of oleic acid to 10-hydroxystearic acid by two species of ruminal bacteria  

Microsoft Academic Search

Bacteria able to convert oleic acid to 10-hydroxystearic acid were isolated from the ovine rumen. The solid hydroxy fatty acid produced from bacterial fermentations containing oleic acid was recovered by filtration, extraction into ether and crystallisation. The identity of the product was confirmed by HPLC and gas chromatography\\/mass spectrometry. One 10-hydroxystearic-acid-producing bacterial group was represented by two strains of an

J. A. Hudson; C. A. M. MacKenzie; K. N. Joblin

1995-01-01

300

Iron dissolution of dust source materials during simulated acidic processing: the effect of sulfuric, acetic, and oxalic acids.  

PubMed

Atmospheric organic acids potentially display different capacities in iron (Fe) mobilization from atmospheric dust compared with inorganic acids, but few measurements have been made on this comparison. We report here a laboratory investigation of Fe mobilization of coal fly ash, a representative Fe-containing anthropogenic aerosol, and Arizona test dust, a reference source material for mineral dust, in pH 2 sulfuric acid, acetic acid, and oxalic acid, respectively. The effects of pH and solar radiation on Fe dissolution have also been explored. The relative capacities of these three acids in Fe dissolution are in the order of oxalic acid > sulfuric acid > acetic acid. Oxalate forms mononuclear bidentate ligand with surface Fe and promotes Fe dissolution to the greatest extent. Photolysis of Fe-oxalate complexes further enhances Fe dissolution with the concomitant degradation of oxalate. These results suggest that ligand-promoted dissolution of Fe may play a more significant role in mobilizing Fe from atmospheric dust compared with proton-assisted processing. The role of atmospheric organic acids should be taken into account in global-biogeochemical modeling to better access dissolved atmospheric Fe deposition flux at the ocean surface. PMID:23883276

Chen, Haihan; Grassian, Vicki H

2013-09-17

301

Fed-batch fermentation with and without on-line extraction for propionic and acetic acid production by Propionibacterium acidipropionici.  

PubMed

Fed-batch propionic and acetic acid fermentations were performed in semi-defined laboratory medium and in corn steep liquor with Propionibacterium acidipropionici strain P9. On average, over four experiments, 34.5 milligrams propionic acid and 12.8 milligrams acetic acid were obtained in about 146 h in laboratory medium with 79 milligrams glucose added over five feeding periods. The highest concentration of propionic acid, 45 milligrams, was obtained when the glucose concentration was not allowed to drop to zero. In corn steep liquor 35 milligrams propionic acid and 11 milligrams acetic acid were produced in 108 h from 59.4 milligrams total lactic acid provided as seven feedings of corn steep liquor. Extractive fed-batch fermentations were conducted in semi-defined medium using either flat-sheet-supported liquid membranes or hollow-fiber membrane extraction to remove organic acids from the culture medium. As operated during the course of the fermentation, these systems extracted 25% and 22% of the acetic acid and 36.5% and 44.5% of the propionic acid, respectively, produced in the fermentation. Total amounts of acids produced were about the same as in comparable nonextractive fermentations: 30-37 milligrams propionic acid and 13 milligrams acetic acid were produced in 150 h. Limitations on acid production can be attributed to limited substrate feed, not to failure of the extraction system. PMID:8867628

Ozadali, F; Glatz, B A; Glatz, C E

1996-02-01

302

Novel wine yeast with mutations in YAP1 that produce less acetic acid during fermentation.  

PubMed

Acetic acid, a byproduct formed during yeast alcoholic fermentation, is the main component of volatile acidity (VA). When present in high concentrations in wine, acetic acid imparts an undesirable 'vinegary' character that results in a significant reduction in quality and sales. Previously, it has been shown that saké yeast strains resistant to the antifungal cerulenin produce significantly lower levels of VA. In this study, we used a classical mutagenesis method to isolate a series of cerulenin-resistant strains, derived from a commercial diploid wine yeast. Four of the selected strains showed a consistent low-VA production phenotype after small-scale fermentation of different white and red grape musts. Specific mutations in YAP1, a gene encoding a transcription factor required for oxidative stress tolerance, were found in three of the four low-VA strains. When integrated into the genome of a haploid wine strain, the mutated YAP1 alleles partially reproduced the low-VA production phenotype of the diploid cerulenin-resistant strains, suggesting that YAP1 might play a role in (regulating) acetic acid production during fermentation. This study offers prospects for the development of low-VA wine yeast starter strains that could assist winemakers in their effort to consistently produce wine to definable quality specifications. PMID:23146134

Cordente, Antonio G; Cordero-Bueso, Gustavo; Pretorius, Isak S; Curtin, Christopher D

2013-02-01

303

A Glutamic Acid-Producing Lactic Acid Bacteria Isolated from Malaysian Fermented Foods  

PubMed Central

l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently ?-amino butyric acid (GABA) as a bioactive compound.

Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B.; Saari, Nazamid

2012-01-01

304

Kinetic analysis on formation of poly(3-hydroxybutyrate) from acetic acid by Ralstonia eutropha under chemically defined conditions  

Microsoft Academic Search

  Batch cultures of Ralstonia eutropha in chemically defined media with acetic acid (HAc) as the sole carbon source were conducted to investigate acetate utilization,\\u000a formation of poly(3-hydroxybutyrate) (PHB) and growth of active biomass (ABM) under different carbon to nitrogen (C\\/N) weight\\u000a ratios. The specific acetate utilization rate based on ABM approached 0.16 g\\/g ABM h?1, which was not affected very

J Wang; J Yu

2001-01-01

305

Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts  

SciTech Connect

The influence of the factors acetic acid, furfural, and p-hydroxybenzoic acid on the ethanol yield (Y{sub EtOH}) of Saccharomyces cerevisiae, bakers` yeast, S. cerevisiae ATCC 96581, and Candida shehatae NJ 23 was investigated using a 2{sup 3}-full factorial design with 3 centerpoints. The results indicated that acetic acid inhibited the fermentation by C. shehatae NJ 23 markedly more than by bakers` yeast, whereas no significant difference in tolerance towards the compounds was detected between the S. cerevisiae strains. Furfural and the lignin derived compound p-hydroxybenzoic acid did not affect any of the yeasts at the cell mass concentration used. The results indicated that the linear model was not adequate to describe the experimental data. Based on the results from the 2{sup 3}-full factorial experiment, an extended experiment was designed based on a central composite design to investigate the influence of the factors on the specific growth rate ({mu}), biomass yield (Y{sub x}), volumetric ethanol productivity (Q{sub EtOH}), and Y{sub EtOH}. Bakers` yeast was chosen in the extended experiment due to its better tolerance towards acetic acid, which makes it a more interesting organism for use in industrial fermentations of lignocellulosic hydrolysates.

Palmqvist, E.; Grage, H.; Meinander, N.Q.; Hahn-Haegerdal, B. [Univ. of Lund (Sweden)

1999-04-05

306

Modified alginate and chitosan for lactic acid bacteria immobilization.  

PubMed

Beads with enhanced-stability acid media, which were based on alginate and chitosan functionalized by succinylation (increasing the anionic charges able to retain protons) or by acylation (improving matrix hydrophobicity), were developed for immobilization of bacterial cells. Beads (3 mm diameter) formed by ionotropic gelation with CaCl(2) presented good mechanical characteristics. After 30 min incubation of viable free Lactobacillus rhamnosus cells in simulated gastric fluid (pH 1.5), we noticed that the level of viable bacteria was undetectable. Bacterial immobilization in native-alginate-based beads generated a viable-cell count of 22-26%, whereas, when entrapped in succinylated alginate and chitosan beads, the percentage of viable cells was of 60 and 66%, respectively. Best viability (87%) was found for bacteria immobilized in N -palmitoylaminoethyl alginate, which affords a high protective effect, probably due to long alkyl pendants that improve the beads' hydrophobicity, limiting hydration in the acidic environment. PMID:15154848

Le-Tien, Canh; Millette, Mathieu; Mateescu, Mircea-Alexandru; Lacroix, Monique

2004-06-01

307

DNA fingerprinting of lactic acid bacteria in sauerkraut fermentations.  

PubMed

Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics. PMID:17921264

Plengvidhya, Vethachai; Breidt, Fredrick; Lu, Zhongjing; Fleming, Henry P

2007-12-01

308

Uncoupling by Acetic Acid Limits Growth of and Acetogenesis by Clostridium thermoaceticum  

PubMed Central

When cells of the anaerobic thermophile Clostridium thermoaceticum grow in batch culture and homoferment glucose to acetic acid, the pH of the medium decreases until growth and then acid production cease, at about pH 5. We postulated that the end product of fermentation limits growth by acting as an uncoupling agent. Thus, when the pH of the medium is low, the cytoplasm of the cells becomes acidified below a tolerable pH. We have therefore measured the internal pH of growing cells and compared these values with those of nongrowing cells incubated in the absence of acetic acid. Growing cells maintained an interior about 0.6 pH units more alkaline than the exterior throughout most of batch growth (i.e., ?pH = 0.6). We also measured the transmembrane electrical potential (??), which decreased from 140 mV at pH 7 at the beginning of growth to 80 mV when the medium had reached pH 5. The proton motive force, therefore, was 155 mV at pH 7, decreasing to 120 mV at pH 5. When further fermentation acidified the medium below pH 5, both the ?pH and the ?? collapsed, indicating that these cells require an internal pH of at least 5.5 to 5.7. Cells harvested from stationary phase and suspended in citrate-phosphate buffer maintained a ?pH of 1.5 at external pH 5.0. This ?pH was dissipated by acetic acid (at the concentrations found in the growth medium) and other weak organic acids, as well as by ionophores and inhibitors of glycolysis and of the H+-ATPase. Nongrowing cells had a ?? which ranged from about 116 mV at external pH 7 to about 55 mV at external pH 5 and which also was sensitive to ionophores. Since acetic acid, in its un-ionized form, diffuses passively across the cytoplasmic membrane, it effectively renders the membrane permeable to protons. It therefore seems unlikely that mutations at one or a few loci would result in C. thermoaceticum cells significantly more acetic acid tolerant than their parental type.

Baronofsky, Jerald J.; Schreurs, Wilhelmus J. A.; Kashket, Eva R.

1984-01-01

309

DFT computation and experimental analysis of vibrational and electronic spectra of phenoxy acetic acid herbicides  

NASA Astrophysics Data System (ADS)

An absolute vibrational analysis has been attempted on the basis of experimental FTIR and NIR-FT Raman spectra with calculated vibrational wavenumbers and intensities of phenoxy acetic acids. The equilibrium geometry, bonding features and harmonic vibrational wavenumbers have been calculated with the help of B3LYP method with Dunning correlation consistent basis set aug-cc-pVTZ. The electronic structures of molecular fragments were described in terms of natural bond orbital analysis, which shows intermolecular Osbnd H⋯O and intramolecular Csbnd H⋯O hydrogen bonds. The electronic absorption spectra with different solvents have been investigated in combination with time-dependent density functional theory calculation. The pKa values of phenoxy acetic acids were compared.

Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

2013-05-01

310

Identification of acetate-oxidizing bacteria in a coastal marine surface sediment by RNA-stable isotope probing in anoxic slurries and intact cores.  

PubMed

We investigated the terminal electron-accepting pathways and the acetate-oxidizing bacteria in surface sediment (0-5 mm depth) of Aarhus Bay, Denmark, in anoxic slurry and intact core incubations. In the intact cores, oxygen, nitrate, oxides of manganese and iron, and sulfate were all available and likely all used as electron acceptors by the microbial community, whereas microbial iron and sulfate reduction dominated in the slurries. The availability of electron acceptors clearly affected which organisms were labeled by 16S rRNA-stable isotope probing (SIP). Members of the Oceanospirillaceae were identified as (13) C-acetate oxidizers in both types of incubations, but bacteria related to Colwellia and Arcobacter oxidized acetate in the intact core, while members of the Desulfuromonadales and Acidithiobacillaceae did so in the slurry incubation. Desulfuromonadales sequences also dominated 16S rRNA gene clone libraries from the highest positive dilution of the acetate-oxidizing most probable number cultures with manganese and iron oxides. Thus, members of Desulfuromonadales are likely important for acetate oxidation coupled to iron and manganese reduction in situ, while the identified Gammaproteobacteria and affiliates of Arcobacter may utilize oxygen, nitrate and manganese oxides. Our study further highlights some of the biases that are associated with the use of RNA-SIP as well as slurry and intact core incubations. PMID:23289443

Vandieken, Verona; Thamdrup, Bo

2013-05-01

311

Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria  

PubMed Central

Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

Kaur, Baljinder; Kumar, Balvir

2013-01-01

312

Pharmacological activity of 2% aqueous acetic acid extract of Alhagi maurorum roots  

Microsoft Academic Search

A 2% aqueous acetic acid extract of Alhagi maurorum powdered roots was examined for its pharmacological activity and showed the following results: (1) Administration of the extract intraperitoneally into mice decreased the body temperature in a dose dependent manner. The decreases ranged from 2.5 to 7.3°C. (2) Treatment of the frog rectus abdominis muscle with the extract in doses of

M. S. Marashdah; A. I. Farraj

2010-01-01

313

5,6-Dimethylxanthenone-4Acetic Acid (DMXAA): a New Biological Response Modifier for Cancer Therapy  

Microsoft Academic Search

The investigational anti-cancer drug5,6-dimethylxanthenone-4-acetic acid(DMXAA) was developed by the AucklandCancer Society Research Centre (ACSRC). Ithas recently completed Phase I trials inNew Zealand and UK under the direction ofthe Cancer Research Campaign's Phase I\\/IIClinical Trials Committee. As a biologicalresponse modifier, pharmacological andtoxicological properties of DMXAA areremarkably different from most conventionalchemotherapeutic agents. Induction ofcytokines (particularly tumour necrosisfactor (TNF-a), serotonin and nitricoxide (NO)),

Shufeng Zhou; Philip Kestell; Bruce C. Baguley; James W. Paxton

2002-01-01

314

Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from Azolla.  

PubMed

Arthrobacter species, isolated from the leaf cavities and the microsporocarps of the aquatic fern species Azolla pinnata and Azolla filiculoides, produced indole-3-acetic acid (IAA) in culture when the precursor tryptophan was added to the medium. No IAA production was detected in the absence of tryptophan. Maximum IAA formation was obtained in the first 2 d of incubation. Part of the tryptophan was transformed to N alpha-acetyl-L-tryptophan. PMID:1564446

Forni, C; Riov, J; Grilli Caiola, M; Tel-Or, E

1992-02-01

315

Influence of the carrier on steam reforming of acetic acid over Ru-based catalysts  

Microsoft Academic Search

The reaction of steam reforming of acetic acid (HAc), a model compound of pyrolysis-oil, over ruthenium catalysts supported on Al2O3 and MgO\\/Al2O3 carriers has been investigated employing transient and steady-state techniques. Main objective is the establishment of the reaction network over a wide temperature range and the elucidation of the role of MgO on intrinsic catalytic activity. It has been

Aristides C. Basagiannis; Xenophon E. Verykios

2008-01-01

316

Recent developments in the selective oxidation of propane to acrylic and acetic acids  

Microsoft Academic Search

The oxidation of propane to acrylic and acetic acids has been studied using a Mo1Nb0.08Sb0.25V0.3 mixed oxide catalyst, calcined and activated before reaction under different conditions (T=500 or 600°C in atmospheres of N2, static air, and flowing air (dry or with water or ammonia addition)). Catalytic testing was performed at 400°C in a plug flow microreactor and the characterisation of

J. C. Védrine; E. K. Novakova; E. G. Derouane

2003-01-01

317

Direct catalytic conversion of methane to acetic acid in an aqueous medium  

Microsoft Academic Search

ALTHOUGH methane is the most-abundant of alkanes, hazards of handling and distribution prevent known methane reserves1,2 from being fully exploited. Moreover, it is the least reactive alkane, so whereas selective conversion to more useful chemical products would be of great value, it is difficult to achieve. A useful target molecule for methane conversion is acetic acid, but existing approaches to

Minren Lin; Ayusman Sen

1994-01-01

318

Acetic acid conditioning stimulus induces long-lasting antinociception of somatic inflammatory pain  

Microsoft Academic Search

A wide variety of noxious stimuli are known to induce a powerful inhibition of pain sensation evoked at a remote region of the body. Here we show that an intraperitoneal acetic acid (AA) conditioning stimulus produces long-lasting inhibition of formalin-evoked somatic inflammatory pain behavior in mice. This novel long-lasting antinociception was completely blocked by the 5-hydroxytryptamine type 2A\\/2C (5-HT2A\\/2C) receptor

Takashi Kurihara; Takahiro Nonaka; Tsutomu Tanabe

2003-01-01

319

On the unusual IR spectra of the acetic acid-trimethylamine complex in low temperature matrices  

NASA Astrophysics Data System (ADS)

Usually the stretching vibration of the A-H group in hydrogen-bonded complexes gives an intense, broad absorption in the IR spectrum. However in a few complexes it has proved difficult to detect this absorption in low temperature matrices. In this work the Ratajczak-Yaremko vibrational model of the hydrogen bond has been applied to simulate the IR spectrum obtained for one such complex: the acetic acid-trimethylamine, ACA-TMA, hydrogen bonded complex isolated in an argon matrix.

Ratajczak, Henryk; Wierzejewska, Maria; Barnes, Austin J.; Yaremko, Anatoly M.; Virko, Serdej V.

2014-06-01

320

Alkaline pre-treatment of rice hulls for hydrothermal production of acetic acid  

Microsoft Academic Search

To solve the blockage caused by silica during the hydrothermal conversion of rice hulls into acetic acid in a continuous-flow reactor, the removal of silica from rice hulls and the retainment of organics by alkaline extraction were carried out in a range of pH values from 5 to 12 and temperatures from 30 to 85°C. It was found that the

Yamin Hsieh; Yingxun Du; Fangming Jin; Zhouyu Zhou; Heiji Enomoto

2009-01-01

321

Definitive identification of indole-3-acetic acid and abscisic acid in shoots of Coleus blumei by gas chromatography-mass spectrometry  

Microsoft Academic Search

Mass spectra provide definitive identification of indole-3-acetic acid and abscisic acid in shoots of Coleus blumei, a species used for studying the hormone control of plant development since the early 1930s.

Clifford E. LaMotte; Xiaoyue Li; William P. Jacobs

1998-01-01

322

Reductions of aldehydes and ketones with a readily available N-heterocyclic carbene borane and acetic acid  

PubMed Central

Summary Acetic acid promotes the reduction of aldehydes and ketones by the readily available N-heterocyclic carbene borane, 1,3-dimethylimidazol-2-ylidene borane. Aldehydes are reduced over 1–24 h at room temperature with 1 equiv of acetic acid and 0.5 equiv of the NHC-borane. Ketone reductions are slower but can be accelerated by using 5 equiv of acetic acid. Aldehydes can be selectively reduced in the presence of ketones. On a small scale, products are isolated by evaporation of the reaction mixture and direct chromatography.

Lamm, Vladimir; Pan, Xiangcheng

2013-01-01

323

Preyssler-Structured Tungstophosphoric Acid Catalyst on Functionalized Silica for Esterification of n Butanol with Acetic Acid  

Microsoft Academic Search

The Preyssler-structured tungstophosphoric acid catalyst supported on functionalized silica (Preyssler\\/F-silica) was prepared\\u000a by means of grafting technique with amine group as coupling media, and its catalytic behavior was investigated in the esterification\\u000a of n-butanol with acetic acid. The catalyst was characterized by infra-red spectroscopy, UV–Vis spectroscopy, Hammett indicator\\u000a and N2 adsorption techniques. Catalysts prepared directly by impregnating Preyssler acid on

Shanshan Wu; Weihong Zhang; Jun Wang; Xiaoqian Ren

2008-01-01

324

Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi.  

PubMed

This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibition of P. expansum infection in wounds of Golden Delicious apples. Four strains (TC97, AC318, TM319, and FF441) reduced the fungal rot diameter of the apples by 20%; only Weissella cibaria strain TM128 decreased infection levels by 50%. Cell-free supernatants of selected antagonistic bacteria were studied to determine the nature of the antimicrobial compounds produced. Organic acids were the preferred mediators of inhibition but hydrogen peroxide was also detected when strains BC48, TM128, PM141 and FF441 were tested against E. carotovora. While previous reports of antifungal activity by LAB are scarce, our results support the potential of LAB as biocontrol agents against postharvest rot. PMID:19204894

Trias, Rosalia; Bañeras, Lluís; Montesinos, Emilio; Badosa, Esther

2008-12-01

325

Dykellic Acid Inhibits Phorbol Myristate Acetate-induced Matrix Metalloproteinase- 9 Expression by Inhibiting Nuclear Factor B Transcriptional Activity1  

Microsoft Academic Search

Proteolytic degradation of the extracellular matrix and tumor metas- tasis correlate with expression of endopeptidases known as matrix metal- loproteinases (MMPs). Expression of MMPs is regulated by cytokines and signal transduction pathways, including those activated by phorbol my- ristate acetate. We found that dykellic acid, a fungal metabolite, signifi- cantly inhibits the phorbol myristate acetate-induced increase in MMP-9 expression and

Ju-Hyung Woo; Jong-Wook Park; Sung-Hee Lee; Young-Ho Kim; In Kyu Lee; Edward Gabrielson; Sang-Han Lee; Ho-Jae Lee; Yung-Hee Kho; Taeg Kyu Kwon

2003-01-01

326

Chemical Behaviour of Zirconium Oxychloride Octahydrate and Acetic Acid in Precursor Solution for Zirconia Film Formation on Glass  

Microsoft Academic Search

Precursor solutions for zirconia films on soda lime silica glass substrate were prepared from zirconium oxychloride octahydrate (ZOO) and acetic acid (HOAC) maintaining the mol ratios, [HOAC]\\/[ZOO] = 2, 4, 6, 8 and 10. A characteristic UV absorption band at ~280 nm in the ~120 h aged precursor solutions was identified for acetate group of the zirconium acetato complexed species.

Sunirmal Jana; K. Biswas

1997-01-01

327

Preparation of macroporous lime from natural lime by swelling method with acetic acid for high-temperature desulfurization  

Microsoft Academic Search

To develop a highly active calcium oxide high-temperature desulfurization sorbent, a method of preparation of macroporous calcium oxides from lime was studied. This method is composed of two steps: swelling of the lime and calcination of the swelled sample. Swelling occurred when lime was exposed to the vapor of acetic acid. The swelling resulted from calcium acetate formation in the

Eiji Sasaoka; Norimasa Sada

1998-01-01

328

Pervaporation characteristics of polyetherimide\\/?-alumina composite membrane for a quaternary equilibrium mixture of acetic acid-ethanol-ethyl acetate-water  

Microsoft Academic Search

Polyetherimide\\/?-alumina composite membrane has been prepared by dipping method for further reactor application. Separation\\u000a factors and permeances for a quaternary acetic acid-ethanol-ethyl acetate-water equilibrium feed mixture have been measured\\u000a on the composite membrane in the range of temperature from 303 K up to 343 K and space time from 27 sec to 27,000 sec at a\\u000a permeate-side pressure of 2.67?10-3

Byoung-Gi Park

2004-01-01

329

Nitric oxide: its production in host-cell-infiltrated EMT6 spheroids and its role in tumour cell killing by flavone-8-acetic acid and 5,6-dimethylxanthenone-4-acetic acid  

Microsoft Academic Search

Flavone-8-acetic acid (FAA) and its more dose-potent analogue 5,6-dimethylxanthenone-4-acetic acid (5,6-MeXAA), appear to exert their antitumour effects through vascular and other host-mediated mechanisms and are known to induce the synthesis of nitric oxide by murine macrophages. We investigated the role of nitric oxide in the cytotoxic effects of these drugs in host-cell-infiltrated spheroids. EMT6 murine mammary adenocarcinoma cells were grown

Lindy L. Thomsen; Bruce C. Baguleyl; W. R. Wilson

1992-01-01

330

Synthesis of Saturated Long Chain Fatty Acids from Sodium Acetate-1-C14 by Mycoplasma1  

PubMed Central

Three strains of Mycoplasma, M. laidlawii A and B, and Mycoplasma sp. A60549, were grown in broth containing sodium acetate-1-C14. The methyl esters of the phospholipid fatty acids of harvested radioactive cells were prepared and identified by comparison of their mobilities to known radioactive fatty acid methyl esters by use of a modified reversed-phase partition-thin layer chromatographic technique. No radioactive methyl oleate or methyl linoleate was detected. Compounds migrating as radioactive methyl myristate, stearate, palmitate, and, with less certainty, laurate and octanoate were detected. The qualitative findings for all three organisms appeared similar. M. laidlawii B synthesized a radioactive substance, presumably a saturated fatty acid detected as the methyl ester derivative, which migrated in a position intermediate to methyl myristate-1-C14 and methyl palmitate-1-C14. This work indicates that M. laidlawii A and B and Mycoplasma sp. A60549 are capable, in a complex medium containing fatty acids, of synthesizing saturated but not unsaturated fatty acids entirely or in part from acetate. Images

Pollack, J. D.; Tourtellotte, M. E.

1967-01-01

331

Metabolism of Indole-3-Acetic Acid by Pericarp Discs from Immature and Mature Tomato (Lycopersicon esculentum Mill) 1  

PubMed Central

[1?-14C, 13C6]Indole-3-acetic acid was infiltrated into immature pericarp discs from fruits of tomato (Lycopersicon esculentum Mill., cv Moneymaker). After a 24-h incubation period the discs were extracted with methanol and the partially purified extract was analyzed by reversed-phase high-performance liquid chromatography-radiocounting. Five metabolite peaks (1-5) were detected and subsequently analyzed by combined high-performance liquid chromatography-frit-fast atom bombardment-mass spectrometry. The metabolite 4 fraction was found to contain [13C6]-indole-3-acetylaspartic acid, and analysis of metabolite 5 identified [13C6]indole-3-acetyl-?-d-glucose. The other metabolites could not be identified, but alkaline hydrolysis studies and gel permeation chromatography indicated that metabolites 1 and 3 were both amide conjugates with a molecular weight of approximately 600. Studies with radiolabeled indole-3-acetic acid, indole-3-acetylaspartic acid, and indole-3-acetyl-?-d-glucose demonstrated that in immature pericarp indole-3-acetic acid is deactivated primarily via metabolism to indole-3-acetylaspartic acid, which is further converted to metabolites 1, 2, and 3. In mature, pink pericarp discs, indole-3-acetic acid is converted more extensively to its glucosyl conjugate. Conjugation of indole-3-acetic acid to indole-3-acetylaspartic acid appears to be dependent upon protein synthesis because it is inhibited by cycloheximide. In contrast, cycloheximide has little effect on the further conversion of indole-3-acetylaspartic acid to metabolites 1, 2, and 3.

Catala, Carmen; Ostin, Anders; Chamarro, Jesus; Sandberg, Goran; Crozier, Alan

1992-01-01

332

Preservation of acidified cucumbers with a natural preservative combination of fumaric acid and allyl isothiocyanate that target lactic acid bacteria and yeasts.  

PubMed

Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but spoilage then occurred due to growth of fermentative yeasts, which produced ethanol in the cucumbers. Allyl isothiocyanate (2 mM) prevented growth of Zygosaccharomyces globiformis, which has been responsible for commercial pickle spoilage, as well as the yeasts that were present on fresh cucumbers. However, allyl isothiocyanate did not prevent growth of Lactobacillus plantarum. When these compounds were added in combination to acidified cucumbers, the cucumbers were successfully preserved as indicated by the fact that neither yeasts or lactic acid bacteria increased in numbers nor were lactic acid or ethanol produced by microorganisms when cucumbers were stored at 30 degrees C for at least 2 mo. This combination of 2 naturally occurring preservative compounds may serve as an alternative approach to the use of sodium benzoate or sodium metabisulfite for preservation of acidified vegetables without a thermal process. PMID:20546411

Pérez-Díaz, I M; McFeeters, R F

2010-05-01

333

Restoration of Normal Glutamic Acid Transport in Vitamin B6-Deficient Lactobacillus Plantarum by Acetate, Ammonium, and Vitamin B6.  

National Technical Information Service (NTIS)

A vitamin B6-deficiency in Lactobacillus plantarum markedly reduces the amount of glutamate and other amino acids which can be taken up and accumulated from buffered solutions. The capacity for glutamate accumulation is restored to normal levels when acet...

J. T. Holden

1964-01-01

334

Efficient Synthesis of Primary Amides from Carboxylic Acids using N,N?-Carbonyldiimidazole and Ammonium Acetate in Ionic Liquid  

Microsoft Academic Search

A novel and efficient method for the conversion of carboxylic acids to primary amides using N,N?-carbonyldiimidazole in combination with ammonium acetate\\/triethyl amine system in [BMIM]BF4 is developed.

Kwan Soo Lee; Kee D. Kim

2011-01-01

335

Vapor–liquid equilibria for water + acetic acid + ( N, N-dimethylformamide or dimethyl sulfoxide) at 13.33 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data of the systems acetic acid+N,N-dimethylformamide (DMF), acetic acid+dimethyl sulfoxide (DMSO), DMSO+water, water+acetic acid+DMF, and water+acetic acid+DMSO have been measured at 13.33kPa by using an improved Rose equilibrium still. The association of acetic acid in vapor phase has been considered, and the nonideality of vapor phase was accounted for using the Hayden–O’Connell (HOC) method. The experimental

Yong Peng; Lijuan Ping; Shengli Lu; Jianwei Mao

2009-01-01

336

Growth and Metabolism of Lactic Acid Bacteria during and after Malolactic Fermentation of Wines at Different pH  

PubMed Central

Commercially produced red wines were adjusted to pH 3.0, 3.2, 3.5, 3.7, or 4.0 and examined during and after malolactic fermentation for growth of lactic acid bacteria and changes in the concentrations of carbohydrates, organic acids, amino acids, and acetaldehyde. With one exception, Leuconostoc oenos conducted the malolactic fermentation in all wines and was the only species to occur in wines at pH below 3.5. Malolactic fermentation by L. oenos was accompanied by degradation of malic, citric, and fumaric acids and production of lactic and acetic acids. The concentrations of arginine, histidine, and acetaldehyde also decreased at this stage, but the behavior of hexose and pentose sugars was complicated by other factors. Pediococcus parvulus conducted the malolactic fermentation in one wine containing 72 mg of total sulfur dioxide per liter. Fumaric and citric acids were not degraded during this malolactic fermentation, but hexose sugars were metabolized. P. parvulus and species of Lactobacillus grew after malolactic fermentation in wines with pH adjusted above 3.5. This growth was accompanied by the utilization of wine sugars and production of lactic and acetic acids.

Davis, C. R.; Wibowo, D. J.; Lee, T. H.; Fleet, G. H.

1986-01-01

337

Current taxonomy of phages infecting lactic acid bacteria  

PubMed Central

Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp., and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species.

Mahony, Jennifer; van Sinderen, Douwe

2013-01-01

338

Development of Mucosal Vaccines Based on Lactic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

339

Industrial production of amino acids by coryneform bacteria.  

PubMed

In the 1950s Corynebacterium glutamicum was found to be a very efficient producer of L-glutamic acid. Since this time biotechnological processes with bacteria of the species Corynebacterium developed to be among the most important in terms of tonnage and economical value. L-Glutamic acid and L-lysine are bulk products nowadays. L-Valine, L-isoleucine, L-threonine, L-aspartic acid and L-alanine are among other amino acids produced by Corynebacteria. Applications range from feed to food and pharmaceutical products. The growing market for amino acids produced with Corynebacteria led to significant improvements in bioprocess and downstream technology as well as in molecular biology. During the last decade big efforts were made to increase the productivity and to decrease the production costs. This review gives an overview of the world market for amino acids produced by Corynebacteria. Significant improvements in bioprocess technology, i.e. repeated fed batch or continuous production are summarised. Bioprocess technology itself was improved furthermore by application of more sophisticated feeding and automatisation strategies. Even though several amino acids developed towards commodities in the last decade, side aspects of the production process like sterility or detection of contaminants still have increasing relevance. Finally one focus of this review is on recent developments in downstream technology. PMID:12948636

Hermann, Thomas

2003-09-01

340

Mutants of the pentose-fermenting yeast Pachysolen tannophilus tolerant to hardwood spent sulfite liquor and acetic acid.  

PubMed

A strain development program was initiated to improve the tolerance of the pentose-fermenting yeast Pachysolen tannophilus to inhibitors in lignocellulosic hydrolysates. Several rounds of UV mutagenesis followed by screening were used to select for mutants of P. tannophilus NRRL Y2460 with improved tolerance to hardwood spent sulfite liquor (HW SSL) and acetic acid in separate selection lines. The wild type (WT) strain grew in 50 % (v/v) HW SSL while third round HW SSL mutants (designated UHW301, UHW302 and UHW303) grew in 60 % (v/v) HW SSL, with two of these isolates (UHW302 and UHW303) being viable and growing, respectively, in 70 % (v/v) HW SSL. In defined liquid media containing acetic acid, the WT strain grew in 0.70 % (w/v) acetic acid, while third round acetic acid mutants (designated UAA301, UAA302 and UAA303) grew in 0.80 % (w/v) acetic acid, with one isolate (UAA302) growing in 0.90 % (w/v) acetic acid. Cross-tolerance of HW SSL-tolerant mutants to acetic acid and vice versa was observed with UHW303 able to grow in 0.90 % (w/v) acetic acid and UAA302 growing in 60 % (v/v) HW SSL. The UV-induced mutants retained the ability to ferment glucose and xylose to ethanol in defined media. These mutants of P. tannophilus are of considerable interest for bioconversion of the sugars in lignocellulosic hydrolysates to ethanol. PMID:24122119

Harner, Nicole K; Bajwa, Paramjit K; Habash, Marc B; Trevors, Jack T; Austin, Glen D; Lee, Hung

2014-01-01

341

Dissociation constant of acetic acid in N-methylpropionamide from 5 to 55°C and related thermodynamic quantities  

Microsoft Academic Search

The dissociation constant of acetic acid in N-methylpropionamide (NMP) has been determined at 11 temperatures from 5 to 55°C by measurement of the electromotive force of cells without liquid junction containing hydrogen gas electrodes and silver-silver chloride electrodes. The pK at 25°C was found to be 7.995 (molal scale) as compared with 4.756 in water; thus, acetic acid is much

Edgar S. Etz; R. A. Robinson; Roger G. Bates

1972-01-01

342

Lactic acid bacteria with health claims—interactions and interference with gastrointestinal flora  

Microsoft Academic Search

Lactic acid bacteria in foods have a long history of safe use. Members of the genera Lactococcus and Lactobacillus have a ‘generally-recognised-as-safe’ status, whilst members of the genera Streptococcus and Enterococcus and some other genera of lactic acid bacteria contain opportunistic pathogens. New species and more specific strains of probiotic bacteria are constantly being identified. Prior to incorporating new strains

Tiina Mattila-Sandholm; Jaana Mättö; Maria Saarela

1999-01-01

343

Influence of heated vegetable oils and ??tocopheryl acetate supplementation on ??tocopherol, fatty acids and lipid peroxidation in chicken muscle  

Microsoft Academic Search

1. Chicks were fed on diets containing fresh, heated or ??tocopheryl acetate?supplemented heated vegetable oils. The effects on ??tocopherol status, and on the fatty acid composition and oxidative stability of thigh and breast muscle were determined.2. Plasma ??tocopherol was significantly correlated with ??tocopherol concentrations in thigh and breast muscle.3. The fatty acid profiles of muscle lipids reflected dietary fatty acid

P. J. A. Sheehy; P. A. Morrissey; A. Flynn

1993-01-01

344

Development of a kinetic model for the esterification of acetic acid with methanol in the presence of a homogeneous acid catalyst  

Microsoft Academic Search

The esterification kinetics of acetic acid with methanol in the presence of hydrogen iodide as a homogeneous acid catalyst was studied with isothermal batch experiments at 30–60°C. The catalyst concentration was varied between 0.05 and 10.0 wt%. The experiments revealed that besides the main reaction, the esterification of acetic acid, a side reaction appeared: the catalyst, hydrogen iodide, was esterified

Robert Rönnback; Tapio Salmi; Antti Vuori; Heikki Haario; Juha Lehtonen; Anna Sundqvist; Esko Tirronen

1997-01-01

345

Ability of Thermophilic Lactic Acid Bacteria To Produce Aroma Compounds from Amino Acids  

PubMed Central

Although a large number of key odorants of Swiss-type cheese result from amino acid catabolism, the amino acid catabolic pathways in the bacteria present in these cheeses are not well known. In this study, we compared the in vitro abilities of Lactobacillus delbrueckii subsp. lactis, Lactobacillus helveticus, and Streptococcus thermophilus to produce aroma compounds from three amino acids, leucine, phenylalanine, and methionine, under mid-pH conditions of cheese ripening (pH 5.5), and we investigated the catabolic pathways used by these bacteria. In the three lactic acid bacterial species, amino acid catabolism was initiated by a transamination step, which requires the presence of an ?-keto acid such as ?-ketoglutarate (?-KG) as the amino group acceptor, and produced ?-keto acids. Only S. thermophilus exhibited glutamate dehydrogenase activity, which produces ?-KG from glutamate, and consequently only S. thermophilus was capable of catabolizing amino acids in the reaction medium without ?-KG addition. In the presence of ?-KG, lactobacilli produced much more varied aroma compounds such as acids, aldehydes, and alcohols than S. thermophilus, which mainly produced ?-keto acids and a small amount of hydroxy acids and acids. L. helveticus mainly produced acids from phenylalanine and leucine, while L. delbrueckii subsp. lactis produced larger amounts of alcohols and/or aldehydes. Formation of aldehydes, alcohols, and acids from ?-keto acids by L. delbrueckii subsp. lactis mainly results from the action of an ?-keto acid decarboxylase, which produces aldehydes that are then oxidized or reduced to acids or alcohols. In contrast, the enzyme involved in the ?-keto acid conversion to acids in L. helveticus and S. thermophilus is an ?-keto acid dehydrogenase that produces acyl coenzymes A.

Helinck, Sandra; Le Bars, Dominique; Moreau, Daniel; Yvon, Mireille

2004-01-01

346

Inhibitory Effect of Curcumin, Chlorogenic Acid, Caffeic Acid, and Ferulic Acid on Tumor Promotion in Mouse Skin by 12-O-Tetradecanoylphorbol-13-acetate  

Microsoft Academic Search

The effects of topically applied curcumin, chlorogenic acid, caffeic acid, and ferulic acid on 12-O-tetradecanoylphorbol-13-acetate (TPA)- induced epidermal ornithine decarboxylase activity, epidermal DNA syn thesis, and the promotion of skin tumors were evaluated in female CD-I mice. Topical application of 0.5, 1, 3, or 10 iano\\\\ of curcumin inhibited by 31, 46, 84, or 98%, respectively, the induction of epidermal

Mou-Tuan Huang; Robert C. Smart; Ching-Quo Wong; Allan H. Conney

347

Genomic reconstruction of transcriptional regulatory networks in lactic acid bacteria  

PubMed Central

Background Genome scale annotation of regulatory interactions and reconstruction of regulatory networks are the crucial problems in bacterial genomics. The Lactobacillales order of bacteria collates various microorganisms having a large economic impact, including both human and animal pathogens and strains used in the food industry. Nonetheless, no systematic genome-wide analysis of transcriptional regulation has been previously made for this taxonomic group. Results A comparative genomics approach was used for reconstruction of transcriptional regulatory networks in 30 selected genomes of lactic acid bacteria. The inferred networks comprise regulons for 102 orthologous transcription factors (TFs), including 47 novel regulons for previously uncharacterized TFs. Numerous differences between regulatory networks of the Streptococcaceae and Lactobacillaceae groups were described on several levels. The two groups are characterized by substantially different sets of TFs encoded in their genomes. Content of the inferred regulons and structure of their cognate TF binding motifs differ for many orthologous TFs between the two groups. Multiple cases of non-orthologous displacements of TFs that control specific metabolic pathways were reported. Conclusions The reconstructed regulatory networks substantially expand the existing knowledge of transcriptional regulation in lactic acid bacteria. In each of 30 studied genomes the obtained regulatory network contains on average 36 TFs and 250 target genes that are mostly involved in carbohydrate metabolism, stress response, metal homeostasis and amino acids biosynthesis. The inferred networks can be used for genetic experiments, functional annotations of genes, metabolic reconstruction and evolutionary analysis. All reconstructed regulons are captured within the Streptococcaceae and Lactobacillaceae collections in the RegPrecise database (http://regprecise.lbl.gov).

2013-01-01

348

Fermentation of aqueous plant seed extracts by lactic acid bacteria  

SciTech Connect

The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

Schafner, D.W.; Beuchat, R.L.

1986-05-01

349

Rapid identification, by use of the LTQ Orbitrap hybrid FT mass spectrometer, of antifungal compounds produced by lactic acid bacteria.  

PubMed

Fungal contamination of food causes health and economic concerns. Several species of lactic acid bacteria (LAB) have antifungal activity which may inhibit food spoilage fungi. LAB have GRAS (generally recognised as safe) status, allowing them to be safely integrated into food systems as natural food preservatives. A method is described herein that enables rapid screening of LAB cultures for 25 known antifungal compounds associated with LAB. This is the first chromatographic method developed which enables the rapid identification of a wide range of antifungal compounds by a single method with a short analysis time (23 min). Chromatographic separation was achieved on a Phenomenex Gemini C18 100A column (150 mm?×?2.0 mm; 5 ?m) by use of a mobile-phase gradient prepared from (A) water containing acetic acid (0.1%) and (B) acetonitrile containing acetic acid (0.1%), at a flow rate of 0.3 µL min(-1). The gradient involved a progressive ramp from 10-95% acetonitrile over 13 min. The LC was coupled to a hybrid LTQ Orbitrap XL fourier-transform mass spectrometer (FTMS) operated in negative ionisation mode. High mass accuracy data (<3 ppm) obtained by use of high resolution (30,000 K) enabled unequivocal identification of the target compounds. This method allows comprehensive profiling and comparison of different LAB strains and is also capable of the identification of additional compounds produced by these bacteria. PMID:22526638

Brosnan, Brid; Coffey, Aidan; Arendt, Elke K; Furey, Ambrose

2012-07-01

350

Production, recovery and purification of bacteriocins from lactic acid bacteria  

Microsoft Academic Search

Bacteriocins produced by lactic acid bacteria are a heterogeneous group of peptide inhibitors which include lantibiotics\\u000a (class I, e.g. nisin), small heat-stable peptides (class II, e.g. pediocin AcH\\/PA1) and large heat-labile proteins (class\\u000a III, e.g. helveticin J). Many bacteriocins belonging to the first two groups can be successfully used to inhibit undesirable\\u000a microorganisms in foods, but only nisin is produced

E. Parente; A. Ricciardi

1999-01-01

351

Attractiveness to mexican fruit flies of combinations of acetic acid with ammonium\\/amino attractants with emphasis on effects of hunger  

Microsoft Academic Search

Ammonium acetate was more attractive than other ammonium salts to Mexican fruit flies (Anastrepha ludens) in an orchard test. We hypothesized that acetic acid enhanced the attractiveness of ammonia in the orchard test and that acetic acid may similarly enhance attractiveness of AMPu, an attractant consisting of a mixture of ammonium bicarbonate or ammonium carbonate, methylamine HCl, and putrescine. In

D. C. Robacker; D. S. Moreno; A. B. Demilo

1996-01-01

352

Functional fermented whey-based beverage using lactic acid bacteria.  

PubMed

Whey protein concentrate (WPC) is employed as functional food ingredient because of its nutritional value and emulsifying properties. However, the major whey protein beta-lactoglobulin (BLG) is the main cause of milk allergy. The aim of this study was to formulate a fermented whey beverage using selected lactic acid bacteria and WPC35 (WPC containing 35% of proteins) to obtain a fermented product with low lactose and BLG contents and high essential amino acid concentration. Cell viability, lactose consumption, lactic acid production, proteolytic activity, amino acid release and BLG degradation by the selected strains Lactobacillus acidophilus CRL 636, Lactobacillus delbrueckii subsp. bulgaricus CRL 656 and Streptococcus thermophilus CRL 804, as single or mixed (SLaB) cultures were evaluated in WPC35 (10%, w/v) incubated at 37 degrees C for 24h. Then, the fermented WPC35 was mixed with peach juice and calcium lactate (2%, w/v) and stored at 10 degrees C for 28 days. During fermentation, single cultures grew 1.7-3.1 log CFU/ml and produced 25.1-95.0 mmol/l of lactic acid as consequence of lactose consumption (14.0-41.8 mmol/l) after 12h fermentation. L. delbrueckii subsp. bulgaricus CRL 656 was the most proteolytic strain (626 microg/ml Leu) and released the branched-chain essential amino acids Leu (16 microg/ml), Ile (27 microg/ml) and Val (43 microg/ml). All strains were able to degrade BLG in a range of 41-85% after 12h incubation. The starter culture SLaB grew 3.0 log CFU/ml, showed marked pH reduction, produced 122.0 mmol/l of lactic acid, displayed high proteolytic activity (484 microg/ml Leu) releasing Leu (13 microg/ml), Ile (18 microg/ml) and Val (35 microg/ml), and hydrolyzed 92% of BLG. The addition of calcium lactate to WPC35 maintained the drink pH stable during shelf life; no contamination was detected during this period. After 28 days, a decrease in cell viability of all strains was observed being more pronounced for L. delbrueckii subsp. bulgaricus CRL 656 and L. acidophilus CRL 636 (2.3 and 1.9 log CFU/ml, respectively). The results showed that WPC fermentation by rationally selected lactic acid bacteria might be used for developing functional beverages with improved characteristics such as reduced BLG content and increased branched-chain essential amino acids. PMID:20483186

Pescuma, Micaela; Hébert, Elvira María; Mozzi, Fernanda; de Valdez, Graciela Font

2010-06-30

353

Magnesium ion-independent ribonucleic acid depolymerases in bacteria  

PubMed Central

The distribution of ribonucleases among bacteria has been determined from the examination of a wide variety of species. Bacteria that had been growing rapidly on a solid medium were harvested, treated with acetone and incubated in the presence of EDTA between pH4 and pH9. The ribonuclease activity was determined from the rate at which acid-soluble nucleotides were released. Out of nearly 200 strains examined, about 30 did not contain a detectable ribonuclease. The pH optima of ribonucleases in the remainder were sufficiently distinctive to suggest a use in taxonomy. Escherichia coli B was examined in more detail to determine the factors responsible for variations in the ribonuclease content of this bacterium. Growth rate had little influence on ribonuclease content when a complex medium containing no readily assimilable carbohydrate was used; the addition of glucose resulted in a marked increase in ribonuclease and a dependence of enzyme content on growth rate. An increase in the concentration of sodium chloride in the medium decreased the ribonuclease content of bacteria growing on it.

Wade, H. E.; Robinson, H. K.

1966-01-01

354

Diversity of lactic acid bacteria of the bioethanol process  

PubMed Central

Background Bacteria may compete with yeast for nutrients during bioethanol production process, potentially causing economic losses. This is the first study aiming at the quantification and identification of Lactic Acid Bacteria (LAB) present in the bioethanol industrial processes in different distilleries of Brazil. Results A total of 489 LAB isolates were obtained from four distilleries in 2007 and 2008. The abundance of LAB in the fermentation tanks varied between 6.0 × 105 and 8.9 × 108 CFUs/mL. Crude sugar cane juice contained 7.4 × 107 to 6.0 × 108 LAB CFUs. Most of the LAB isolates belonged to the genus Lactobacillus according to rRNA operon enzyme restriction profiles. A variety of Lactobacillus species occurred throughout the bioethanol process, but the most frequently found species towards the end of the harvest season were L. fermentum and L. vini. The different rep-PCR patterns indicate the co-occurrence of distinct populations of the species L. fermentum and L. vini, suggesting a great intraspecific diversity. Representative isolates of both species had the ability to grow in medium containing up to 10% ethanol, suggesting selection of ethanol tolerant bacteria throughout the process. Conclusions This study served as a first survey of the LAB diversity in the bioethanol process in Brazil. The abundance and diversity of LAB suggest that they have a significant impact in the bioethanol process.

2010-01-01

355

The Partitioning of Acetic, Formic, and Phosphoric Acids Between Liquid Water and Steam  

SciTech Connect

The chemical carryover of impurities and treatment chemicals from the boiler to the steam phase, and ultimately to the low-pressure turbine and condenser, can be quantified based on laboratory experiments preformed over ranges of temperature, pH, and composition. The two major assumptions are that thermodynamic equilibrium is maintained and no deposition, adsorption or decomposition occurs. The most recent results on acetic, formic and phosphoric acids are presented with consideration of the effects of hydrolysis and dimerization reactions. Complications arising from thermal decomposition of the organic acids are discussed. The partitioning constants for these acids and other solutes measured in this program have been incorporated into a simple thermodynamic computer code that calculates the effect of chemical and mechanical carryover on the composition of the condensate formed to varying extents in the water/steam cycle.

Gruszkiewicz, M.S.; Marshall, S.L.; Palmer, D.A.; Simonson, J.M.

1999-06-22

356

Okadaic acid: an additional non-phorbol-12-tetradecanoate-13-acetate-type tumor promoter.  

PubMed Central

Okadaic acid is a polyether compound of a C38 fatty acid, isolated from a black sponge, Halichondria okadai. Previous studies showed that okadaic acid is a skin irritant and induces ornithine decarboxylase (OrnDCase; 3-hydroxyl-L-glutamate 1-carboxy-lyase, EC 4.1.1.17) in mouse skin 4 hr after its application to the skin. This induction was strongly inhibited by pretreatment of the skin with 13-cis-retinoic acid. A two-stage carcinogenesis experiment in mouse skin initiated by a single application of 100 micrograms of 7,12-dimethylbenz[a]anthracene (DMBA) and followed by application of 10 micrograms of okadaic acid twice a week revealed that okadaic acid is a potent additional tumor promoter: tumors developed in 93% of the mice treated with DMBA and okadaic acid by week 16. In contrast, tumors were found in only one mouse each in the groups treated with DMBA alone or okadaic acid alone. An average of 2.6 tumors per mouse was found in week 30 in the group treated with DMBA and okadaic acid. Unlike phorbol 12-tetradecanoate 13-acetate (TPA), teleocidin, and aplysiatoxin, okadaic acid did not inhibit the specific binding of [3H]TPA to a mouse skin particulate fraction when added up to 100 microM or activate calcium-activated, phospholipid-dependent protein kinase (protein kinase C) in vitro when added up to 1.2 microM. Therefore, the actions of okadaic acid and phorbol ester may be mediated in different ways. These results show that okadaic acid is a non-TPA-type tumor promoter in mouse skin carcinogenesis.

Suganuma, M; Fujiki, H; Suguri, H; Yoshizawa, S; Hirota, M; Nakayasu, M; Ojika, M; Wakamatsu, K; Yamada, K; Sugimura, T

1988-01-01

357

Toxicokinetics and Oral Bioavailability of Halogenated Acetic Acids Mixtures in Naive and GSTzeta-Depleted Rats  

SciTech Connect

Pharmacokinetics of halogenated acetic acid (HAA) mixtures in native and GSTzeta depleted rats was investigated. Rats were administered orally or i.v. to Mixture-1 (monobromo- dichloro-, chlorodibromo-, tribromo- acetic acids) or Mixture-2 (bromochloro-, dibromo-, trichloro- bromodichloro- acetic acids) at a dose of 25 ?mol/kg HAA and blood samples collected up to 36 h. GSTzeta depleted rats were also orally dosed with each mixture and euthanized at 0.25, 0.5, 1, 2 and 4 h to determine tissue distribution. In Mixture-1, GSTzeta depletion only affected the pharmacokinetics of DCAA, which increased the elimination t? from 9 min to 1.3 h. After oral administration, DCAA exhibited a complex time-course plasma profile with secondary peaks appearing long after completion of the initial absorption phase. This phenomenon coincided with elevated DCA levels in the lower portion of the GI tract compared to CDBAA and TBAA. For Mixture-2, all di-HAAs were eliminated extremely rapidly from plasma in both na?ve and GSTzeta depleted animals (t? was 4-11 min in na?ve and 11-24 min in GSTzeta depleted rats), t? of BDCAA and TCAA was 3.5 and 12 h in na?ve and 2.3 and 7.5 h in GSTzeta depleted rats. The primary difference in the pharmacokinetics among HAAs when administered as mixture was the total body clearance (Clb) which was reduced compared to after individual administration. These results suggest competitive interactions between tri- and di-HAAs beyond what would be predicted from individual HAA studies. For di-HAAs, the total dose is important as clearance is dose dependent due to competition for GSTzeta. When considering HAAs dosimetry, importance should be placed on both the components of the mixture and prior exposure history to di-HAAs.

Saghir, Shakil A.; Schultz, Irv R.

2005-04-01

358

Biosynthesis of Indole-3-Acetic Acid by the Pine Ectomycorrhizal Fungus Pisolithus tinctorius  

PubMed Central

Previous work has indicated that anatomical and morphological changes (stunting and dichotomy) in roots of various conifers may be influenced by plant-growth-regulating substances secreted by mycorrhizae. Indole-3-acetic acid (IAA) has been tentatively identified as a major auxin produced by some selected ectomycorrhizae. We report the isolation and detection of IAA as a secondary metabolite from Pisolithus tinctorius by thin-layer chromatography, high-performance liquid chromatography (HPLC), enzyme-linked immunosorbent (monoclonal antibody) assay (ELISA), and unequivocal identification by gas chromatography-mass spectrometry (GC-MS). The thin-layer chromatography methods for auxin isolation described here are novel, with the use of heptane-acetone-glacial acetic acid as the migrating solvent and formaldehyde, H2SO4, and vanadate in detection. The acidic extract of the culture supernatant was methylated with ethereal diazomethane to detect IAA as methyl-3-IAA by HPLC, ELISA, and GC-MS. The quantitative amount of IAA detected ranged from 4 to 5 ?mol liter?1 by HPLC and ELISA. Another unidentified metabolite was detected by GC-MS with a typical indole nucleus (m/z = 130), indicating that it could be an intermediate in auxin metabolism. Plant response (Pseudotsuga menziesii, Douglas fir) was monitored upon inoculation of P. tinctorius and l-tryptophan. There was a consistent increase in plant height and stem diameter as a result of the two treatments, with statistical differences in dry weights of the shoots and roots. Images

Frankenberger, W. T.; Poth, M.

1987-01-01

359

Kinetics of the • OH-radical initiated reactions of acetic acid and its deuterated isomers  

Microsoft Academic Search

Kinetics of the •OH-initiated reactions of acetic acid and its deuterated isomers have been investigated performing simulation chamber experiments\\u000a at T = 300 ± 2 K. The following rate constant values have been obtained (± 1?, in cm3 molecule?1 s?1): k\\u000a 1(CH3C(O)OH + •OH) = (6.3 ± 0.9) × 10?13, k\\u000a 2(CH3C(O)OD + •OH) = (1.5 ± 0.3) × 10?13,

Emese Szabó; Jérémy Tarmoul; Alexandre Tomas; Christa Fittschen; Sándor Dóbé; Patrice Coddeville

2009-01-01

360

New tetrazole-1-acetic acid esters for enzymatic synthesis of cefazolin  

Microsoft Academic Search

The enzymatic synthesis of cefazolin (CEZ) using esters of tetrazole-1-acetic acid (TzAA esters) with saturated lower alcohols\\u000a is reported. The optimum ratios of acyl-donor:acyl-acceptor in the enzymatic synthesis were determined. It is shown that a\\u000a threefold molar excess of acyl-donor for about 165 min, a conversion rate of about 55% is obtained with these TzAA esters.\\u000a The syntheses were carried

M. Kostadinov; A. Nikolov; N. Tsoneva; N. Petkov

1992-01-01

361

A new CO 2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid  

Microsoft Academic Search

A new disposal process for anthropogenic CO2 via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps:(1)CaSiO3+2CH3COOH?Ca2++2CH3COO?+H2O+SiO2(2)Ca2++2CH3COO?+CO2+H2O?CaCO3?+2CH3COOHStep (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions

M. Kakizawa; A. Yamasaki; Y. Yanagisawa

2001-01-01

362

Indole-3-Acetic Acid Biosynthesis in the Mutant Maize orange pericarp, a Tryptophan Auxotroph.  

PubMed

The maize mutant orange pericarp is a tryptophan auxotroph, which results from mutation of two unlinked loci of tryptophan synthase B. This mutant was used to test the hypothesis that tryptophan is the precursor to the plant hormone indole-3-acetic acid (IAA). Total IAA in aseptically grown mutant seedlings was 50 times greater than in normal seedlings. In mutant seedlings grown on media containing stable isotopelabeled precursors, IAA was more enriched than was tryptophan. No incorporation of label into IAA from tryptophan could be detected. These results establish that IAA can be produced de novo without tryptophan as an intermediate. PMID:17731524

Wright, A D; Sampson, M B; Neuffer, M G; Michalczuk, L; Slovin, J P; Cohen, J D

1991-11-15

363

Simultaneous determination of 2-naphthoxyacetic acid and indole-3-acetic acid by first derivation synchronous fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

A simple, rapid, sensitive and selective method for simultaneously determining 2-naphthoxyacetic acid (BNOA) and Indole-3-Acetic Acid (IAA) in mixtures has been developed using derivation synchronous fluorescence spectroscopy based on their synchronous fluorescence. The synchronous fluorescence spectra were obtained with ?? = 100 nm in a pH 8.5 NaH2PO4-NaOH buffer solution, and the detected wavelengths of quantitative analysis were set at 239 nm for BNOA and 293 nm for IAA respectively. The over lapped fluorescence spectra were well separated by the synchronous derivative method. Under optimized conditions, the limits of detection (LOD) were 0.003 ?g/mL for BNOA and 0.012 ?g/mL for IAA. This method is simple and expeditious, and it has been successfully applied to the determination of 2-naphthoxyacetic acid and indole-3-acetic acid in fruit juice samples with satisfactory results. The samples were only filtrated through a 0.45 ?m membrane filter, which was free from the tedious separation procedures. The obtaining recoveries were in the range of 83.88-87.43% for BNOA and 80.76-86.68% for IAA, and the relative standard deviations were all less than 5.0%. Statistical comparison of the results with high performance liquid chromatography Mass Spectrometry (HPLC-MS) method revealed good agreement and proved that there were no significant difference in the accuracy and precision between these two methods.

Liu, Xiangxiang; Wan, Yiqun

2013-07-01

364

Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage  

PubMed Central

Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage.

Wu, Jing-jing; Du, Rui-ping; Gao, Min; Sui, Yao-qiang; Xiu, Lei; Wang, Xiao

2014-01-01

365

Techno-economic Analysis for the Thermochemical Conversion of Lignocellulosic Biomass to Ethanol via Acetic Acid Synthesis  

SciTech Connect

Biomass is a renewable energy resource that can be converted into liquid fuel suitable for transportation applications. As a widely available biomass form, lignocellulosic biomass can have a major impact on domestic transportation fuel supplies and thus help meet the Energy Independence and Security Act renewable energy goals (U.S. Congress 2007). This study performs a techno-economic analysis of the thermo chemical conversion of biomass to ethanol, through methanol and acetic acid, followed by hydrogenation of acetic acid to ethanol. The conversion of syngas to methanol and methanol to acetic acid are well-proven technologies with high conversions and yields. This study was undertaken to determine if this highly selective route to ethanol could provide an already established economically attractive route to ethanol. The feedstock was assumed to be wood chips at 2000 metric ton/day (dry basis). Two types of gasification technologies were evaluated: an indirectly-heated gasifier and a directly-heated oxygen-blown gasifier. Process models were developed and a cost analysis was performed. The carbon monoxide used for acetic acid synthesis from methanol and the hydrogen used for hydrogenation were assumed to be purchased and not derived from the gasifier. Analysis results show that ethanol selling prices are estimated to be $2.79/gallon and $2.81/gallon for the indirectly-heated gasifier and the directly-heated gasifier systems, respectively (1stQ 2008$, 10% ROI). These costs are above the ethanol market price for during the same time period ($1.50 - $2.50/gal). The co-production of acetic acid greatly improves the process economics as shown in the figure below. Here, 20% of the acetic acid is diverted from ethanol production and assumed to be sold as a co-product at the prevailing market prices ($0.40 - $0.60/lb acetic acid), resulting in competitive ethanol production costs.

Zhu, Yunhua; Jones, Susanne B.

2009-04-01

366

High temperature stimulates acetic acid accumulation and enhances the growth inhibition and ethanol production by Saccharomyces cerevisiae under fermenting conditions.  

PubMed

Cellular responses of Saccharomyces cerevisiae to high temperatures of up to 42 °C during ethanol fermentation at a high glucose concentration (i.e., 100 g/L) were investigated. Increased temperature correlated with stimulated glucose uptake to produce not only the thermal protectant glycerol but also ethanol and acetic acid. Carbon flux into the tricarboxylic acid (TCA) cycle correlated positively with cultivation temperature. These results indicate that the increased demand for energy (in the form of ATP), most likely caused by multiple stressors, including heat, acetic acid, and ethanol, was matched by both the fermentation and respiration pathways. Notably, acetic acid production was substantially stimulated compared to that of other metabolites during growth at increased temperature. The acetic acid produced in addition to ethanol seemed to subsequently result in adverse effects, leading to increased production of reactive oxygen species. This, in turn, appeared to cause the specific growth rate, and glucose uptake rate reduced leading to a decrease of the specific ethanol production rate far before glucose depletion. These results suggest that adverse effects from heat, acetic acid, ethanol, and oxidative stressors are synergistic, resulting in a decrease of the specific growth rate and ethanol production rate and, hence, are major determinants of cell stability and ethanol fermentation performance of S. cerevisiae at high temperatures. The results are discussed in the context of possible applications. PMID:24706214

Woo, Ji-Min; Yang, Kyung-Mi; Kim, Sae-Um; Blank, Lars M; Park, Jin-Byung

2014-07-01

367

Isolation, screening and identification of lactic acid bacteria from traditional food fermentation processes and culture collections  

Microsoft Academic Search

This study describes a search for lactic acid bacteria capable of exo?polysaccharide production or exhibiting antimicrobial or proteolytic activities. About 400 lactic acid bacteria were isolated from traditional fermented foods (sour dough, sausages, table olives, cheese and other dairy products). Together with almost 200 lactic acid bacterial strains obtained from culture collections, these strains were screened for exo?polysaccharide production, bacteriocin

Dick J. C. van den Berg; Annelies Smits; Bruno Pot; Aat M. Ledeboer; Karel Kersters; John M. A. Verbake; C. Theo Verrips

1993-01-01

368

The kinetics of process dependent ammonia inhibition of methanogenesis from acetic acid.  

PubMed

Advanced anaerobic digestion processes aimed at improving the methanization of sewage sludge may be potentially impaired by the production of inhibitory compounds (e.g. free ammonia). The result of methanogenic inhibition is relatively high effluent concentrations of acetic acid and other soluble organics, as well as reduced methane yields. An extreme example of such an advanced process is the thermal hydrolytic pretreatment of sludge prior to high solids digestion (THD). Compared to a conventional mesophilic anaerobic digestion process (MAD), THD operates in a state of constant inhibition driven by high free ammonia concentrations, and elevated pH values. As such, previous investigations of the kinetics of methanogenesis from acetic acid under uninhibited conditions do not necessarily apply well to the modeling of extreme processes such as THD. By conducting batch ammonia toxicity assays using biomass from THD and MAD reactors, we compared the response of these communities over a broad range of ammonia inhibition. For both processes, increased inhibitor concentrations resulted in a reduction of biomass growth rate (r(max) = ?(max)?X) and a resulting decrease in the substrate half saturation coefficient (K(S)). These two parameters exhibited a high degree of correlation, suggesting that for a constant transport limited system, the K(S) was mostly a linear function of the growth rate. After correcting for reactor pH and temperature, we found that the THD and MAD biomass were both able to perform methanogenesis from acetate at high free ammonia concentrations (equivalent to 3-5 g/L total ammonia nitrogen), albeit at less than 30% of their respective maximum rates. The reduction in methane production was slightly less pronounced for the THD biomass than for MAD, suggesting that the long term exposure to ammonia had selected for a methanogenic pathway less dependent on those organisms most sensitive to ammonia inhibition (i.e. aceticlastic methanogens). PMID:23062786

Wilson, Christopher Allen; Novak, John; Takacs, Imre; Wett, Bernhard; Murthy, Sudhir

2012-12-01

369

Influence of ripening container on the lactic acid bacteria population in Tulum cheese  

Microsoft Academic Search

The objective of the present study was to investigate the influence of container material (plastic or goat-skin bag) on the\\u000a growth of lactic acid bacteria in Tulum cheese during 9 months of ripening. The lactic acid bacteria in Tulum cheeses were\\u000a periodically counted on MRS and M17 agars throughout ripening. Results showed that the highest counts of lactic acid bacteria\\u000a on

S. Cakmakci; E. Dagdemir; A. A. Hayaloglu; M. Gurses; E. Gundogdu

2008-01-01

370

Comparative genomics of enzymes in flavor-forming pathways from amino acids in lactic acid bacteria  

Microsoft Academic Search

Lactic acid bacteria (LAB) have been widely used as starter or nonstarter cultures in the dairy industry for over a thousand years. They play an essential role in flavor formation during the fermentation of dairy products. Several metabolic routes can lead to the formation of flavor compounds when LAB are growing in milk. One of the main precursors for flavor

Mengjin Liu; Arjen Nauta; Christof Francke; Roland J. Siezen

2008-01-01

371

Insights into the evolution of sialic acid catabolism among bacteria  

PubMed Central

Background Sialic acids comprise a family of nine-carbon amino sugars that are prevalent in mucus rich environments. Sialic acids from the human host are used by a number of pathogens as an energy source. Here we explore the evolution of the genes involved in the catabolism of sialic acid. Results The cluster of genes encoding the enzymes N-acetylneuraminate lyase (NanA), epimerase (NanE), and kinase (NanK), necessary for the catabolism of sialic acid (the Nan cluster), are confined 46 bacterial species, 42 of which colonize mammals, 33 as pathogens and 9 as gut commensals. We found a putative sialic acid transporter associated with the Nan cluster in most species. We reconstructed the phylogenetic history of the NanA, NanE, and NanK proteins from the 46 species and compared them to the species tree based on 16S rRNA. Within the NanA phylogeny, Gram-negative and Gram-positive bacteria do not form distinct clades. NanA from Yersinia and Vibrio species was most closely related to the NanA clade from eukaryotes. To examine this further, we reconstructed the phylogeny of all NanA homologues in the databases. In this analysis of 83 NanA sequences, Bacteroidetes, a human commensal group formed a distinct clade with Verrucomicrobia, and branched with the Eukaryotes and the Yersinia/Vibrio clades. We speculate that pathogens such as V. cholerae may have acquired NanA from a commensal aiding their colonization of the human gut. Both the NanE and NanK phylogenies more closely represented the species tree but numerous incidences of incongruence are noted. We confirmed the predicted function of the sialic acid catabolism cluster in members the major intestinal pathogens Salmonella enterica, Vibrio cholerae, V. vulnificus, Yersinia enterocolitica and Y. pestis. Conclusion The Nan cluster among bacteria is confined to human pathogens and commensals conferring them the ability to utilize a ubiquitous carbon source in mucus rich surfaces of the human body. The Nan region shows a mosaic evolution with NanA from Bacteroidetes, Vibrio and Yersinia branching closely together with NanA from eukaryotes.

Almagro-Moreno, Salvador; Boyd, E Fidelma

2009-01-01

372

?-(Acetic acid)-di-?-chlorido-bis[tri-phenyl-tellurium(IV)] monohydrate  

PubMed Central

The asymmetric unit of the title compound, C38H34Cl2O2Te2·H2O, contains two independent TeIV cations, each coordinated by three phenyl ligands, two Cl? anions and one acetic acid mol­ecule in a distorted octa­hedral C3Cl2O geometry; the longer Te?Cl distances ranging from 3.2007?(11) to 3.4407?(11)?Å and the longer Te?O distances of 3.067?(3) and 3.113?(3)?Å indicate the weak bridge coordination. The Cl? anion and acetic acid mol­ecule bridge the two independent TeIV cations, forming the dimeric complex mol­ecule, in which the Te?Te separation is 3.7314?(4)?Å. In the crystal, the water molecules of crystallization link the TeIV complex mol­ecules into chains running along the b-axis direction via O—H?O and O—H?Cl hydrogen bonds.

Hu, Feng; Xu, Chao; Shi, Hua-Tian; Chen, Qun; Zhang, Qian-Feng

2013-01-01

373

Azithromycin and erythromycin ameliorate the extent of colonic damage induced by acetic acid in rats  

SciTech Connect

Ulcerative colitis is a common inflammatory bowel disease (IBD) of unknown etiology. Recent studies have revealed the role of some microorganisms in the initiation and perpetuation of IBD. The role of antibiotics in the possible modulation of colon inflammation is still uncertain. In this study, we evaluated the effects of two macrolides, namely azithromycin and erythromycin, at different doses on the extent and severity of ulcerative colitis caused by intracolonic administration of 3% acetic acid in rats. The lesions and the inflammatory response were assessed by histology and measurement of myeloperoxidase (MPO) activity, nitric oxide synthetase (NOS) and tumor necrosis factor alpha (TNF{alpha}) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNF{alpha} was detected in the colonic tissues. Administration of either azithromycin or erythromycin at different dosage (10, 20 and 40 mg/kg orally, daily for 5 consecutive days) significantly (P < 0.05) reduced the colonic damage, MPO and NOS activities as well as TNF{alpha} level. This reduction was highly significant with azithromycin when given at a dose of 40 mg/kg. It is concluded that azithromycin and erythromycin may have a beneficial therapeutic role in ulcerative colitis.

Mahgoub, Afaf [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia)]. E-mail: afaf_mahgoub@yahoo.com; El-Medany, Azza [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Mustafa, Ali [Department of Pharmacology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Arafah, Maha [Department of Pathology, College of Medicine, King Saud University, Riyadh 11461 (Saudi Arabia); Moursi, Mahmoud [Central Laboratories, Ministry of Health, Riyadh (Saudi Arabia)

2005-05-15

374

Transgenically enhanced expression of indole-3-acetic Acid confers hypervirulence to plant pathogens.  

PubMed

ABSTRACT Fusarium oxysporum and F. arthrosporioides, pathogenic on Orobanche aegyptiaca, were transformed with two genes of the indole-3-acetamide (IAM) pathway leading to indole-3-acetic acid (IAA) to attempt to enhance virulence. Transgenic F. oxysporum lines containing both the tryptophan-2-monooxyngenase (iaaM) and indole-3-acetamide hydrolase (iaaH) genes produced significantly more IAA than the wild type. IAM accumulated in culture extracts of F. oxysporum containing iaaM alone. F. arthrosporioides containing only iaaM accumulated IAM and an unidentified indole. Some transformants of F. oxysporum expressing only the iaaM gene also produced more IAA than the wild type. Sub-threshold levels (that barely infect Orobanche) of transgenic F. oxysporum expressing both genes and of F. arthrosporioides expressing iaaM were more effective in suppressing the number and size of Orobanche shoots than the wild type on tomato plants grown in soil mixed with Orobanche seed. Stimulating an auxin imbalance enhanced pathogen virulence by affecting the host in a manner similar to low doses of auxin herbicides such as 2,4-dichlorophenoxy acetic acid. PMID:18944254

Cohen, Barry A; Amsellem, Ziva; Maor, Rudy; Sharon, Amir; Gressel, Jonathan

2002-06-01

375

Amonia gas: an improved reagent for chemical ionization mass spectrometry of bile acid methyl ester acetates  

SciTech Connect

The ammonia chemical ionization mass spectra of 28 methyl ester acetate derivatives of bile acids and related compounds have been determined by gas-liquid chromatography-mass spectrometry. Advantages of ammonia ionization over the previously studied isobutane ionization include a 130 to 270% enhancement in the sensitivity of base peak monitoring, and direct determination of molecular weight from the base peak (M + NH/sub 4//sup +/) in the mass spectrum of any of the derivatives. Minor ions in the ammonia spectra also allow selective detection of 3-keto compounds and can indicate unsaturation or double bond conjugation in the molecule. The significance of these studies for the detection and quantitation of bile acids is discussed. 2 tables.

DeMark, B.R.; Klein, P.D.

1981-01-01

376

An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids  

NASA Technical Reports Server (NTRS)

During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH3COOH) were intercompared in central Virginia. HCOOH and CH3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH-impregnated quartz filters, K2CO3 and NaCO3-impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters using both hi-vol and lo-vol systems to measure particulate phase concentrations. Performances of the mist chamber and K2CO3-impregnated filter techniques were evaluated using zero air and ambient air spiked with HCOOH(g) and CH3COOH(g), and formaldehyde from permeation sources. The advantages and drawbacks of these methods are reported and discussed.

Keene, William C.; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold

1989-01-01

377

Biorefining of wheat straw using an acetic and formic acid based organosolv fractionation process.  

PubMed

To assess the potential of acetic and formic acid organosolv fractionation of wheat straw as basis of an integral biorefinery concept, detailed knowledge on yield, composition and purity of the obtained streams is needed. Therefore, the process was performed, all fractions extensively characterized and the mass balance studied. Cellulose pulp yield was 48% of straw dry matter, while it was 21% and 27% for the lignin and hemicellulose-rich fractions. Composition analysis showed that 67% of wheat straw xylan and 96% of lignin were solubilized during the process, resulting in cellulose pulp of 63% purity, containing 93% of wheat straw cellulose. The isolated lignin fraction contained 84% of initial lignin and had a purity of 78%. A good part of wheat straw xylan (58%) ended up in the hemicellulose-rich fraction, half of it as monomeric xylose, together with proteins (44%), minerals (69%) and noticeable amounts of acids used during processing. PMID:24508905

Snelders, Jeroen; Dornez, Emmie; Benjelloun-Mlayah, Bouchra; Huijgen, Wouter J J; de Wild, Paul J; Gosselink, Richard J A; Gerritsma, Jort; Courtin, Christophe M

2014-03-01

378

Liquid-liquid equilibria of the ternary system water + acetic acid + 1-hexanol  

SciTech Connect

The recovery of organic acids from dilute solutions resulting from fermentation processes is important and many solvents have been tried to improve such recovery. Liquid-liquid equilibria for the ternary system water + acetic acid + 1-hexanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. The UNIQUAC and UNIFAC models satisfactorily predicted the equilibrium compositions.

Fahim, M.A. [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering] [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering; Al-Muhtaseb, S.A.; Al-Nashef, I.M. [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [U.A.E. Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1997-01-01

379

A novel kinetic model for polysaccharide dissolution during atmospheric acetic acid pretreatment of sugarcane bagasse.  

PubMed

Acetic acid (AcH) pretreatment of sugarcane bagasse with the catalysis of sulfuric acid (SA) could greatly enhance the enzymatic digestibility of cellulose. However, polysaccharide dissolution happened inevitably during the pretreatment. It was found that the simplest model, which assumes that the total polysaccharides were reactive to be dissolved, could not well describe the kinetic behavior of polysaccharide dissolution. A novel pseudo-homogenous kinetic model was thus developed by introducing a parameter termed as "potential dissolution degree" (?(d)) based on the multilayered structure of cell wall. It was found that solid xylan and glucan dissolutions were a first-order reaction with respect to the dissolvable fraction. Due to the delignification action of AcH, polysaccharide dissolutions were enhanced in AcH media compared with those in aqueous system. Acetylizations of cellulose and sugars were also observed, and AcH concentration showed a significant influence on the degree of acetylization. PMID:24215769

Zhao, Xuebing; Morikawa, Yuichi; Qi, Feng; Zeng, Jing; Liu, Dehua

2014-01-01

380

Piperidine Acetic Acid Based ?-Secretase Modulators Directly Bind to Presenilin-1  

PubMed Central

A?42 is believed to play a causative role in Alzheimer’s disease (AD) pathogenesis. ?-Secretase modulators (GSMs) are actively being pursued as potential AD therapeutics because they selectively alter the cleavage site of the amyloid precursor protein (APP) to reduce the formation of A?42. However, the binding partner of acid based GSMs was unresolved until now. We have developed clickable photoaffinity probes based on piperidine acetic acid GSM-1 and identified PS1 as the target within the ?-secretase complex. Furthermore, we provide evidence that allosteric interaction of GSMs with PS1 results in a conformational change in the active site of the ?-secretase complex leading to the observed modulation of ?-secretase activity.

2011-01-01

381

Effect of the temperature of dehydration of zeolite on sorption of acetic acid from organic solvents with water  

SciTech Connect

This paper measures the sorption of acetic acid from carbon tetrachloride, toluene, acetone, and water on NaX zeolite dehydrated in air at the temperatures of 370, 470, and 670 K and on nondehydrated zeolite. It was found that the capacity of the sorbent with respect to acetic acid increases in hydrophobic solvents (CCl/sub 4/ and toluene) with a decrease in the degree of dehydration and decreases in hydrophilic acetone. The capacity of the sorbent, the intensity, rate, and relative sorption of acetic acid from aqueous solutions are almost independent of the degree of dehydration of the zeolite. The efficiency of sorption purification of carboxylic acid from organic solvents is primarily predetermined by the intensity of sorption isotherms obtained.

Akhmadeev, V.Y.; Levitskaya, G.D.; Oshchapovskii, V.V.; Shevchuk, I.A.; Tatomyr, Y.T.

1985-05-20

382

Nickel, copper and zinc complexes of (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid  

Microsoft Academic Search

An ester of an imine containing dicarboxylic acid (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid methyl ester was prepared by the reaction of methylbromoacetate with 5-methyl-thiazol-2-ylamine. Base hydrolysis of this ester with sodium hydroxide gives the corresponding disodium salt of the diacid. The disodium salt of (2-methoxycarbonylmethylimino-5-methyl-thiazol-3-yl)-acetic acid (Na2L) forms a mononuclear hexacoordinated complex [Ni(L)(H2O)3]2H2O] with nickel, whereas it forms a pentacoordinated coordination polymer with

W. Marjit Singh; Jubaraj B. Baruah

2008-01-01

383

Stoichiometry of oxygen consumption and sugar, organic acid and amino acid utilization in salivary sediment and pure cultures of oral bacteria.  

PubMed

In each of 23 numerically or metabolically significant oral micro-organisms, and in each of the salivary sediments of 10 humans, oxygen uptake was determined quantitatively with various sugar and organic and amino acid substrates. With relatively few exceptions, the salivary sediments rapidly consumed oxygen with the array of substrates (23) tested. On the other hand, the individual pure cultures oxidized fewer substrates and did so selectively from this menu. The observation that the Gram-positive bacteria readily used oxygen when sugar substrates were provided, but were unable to use oxygen with all but one of the organic and none of the amino acids was significant. The Gram-negative bacteria, in contrast, used oxygen poorly with the sugars but most readily with many of the organic and amino acids, was significant. Only two of the Gram-positive but most of the Gram-negative micro-organisms tested showed oxygen uptake with L(+)-lactate; the Gram-negative bacteria were also active with D(-)-lactate, formate and succinate. Propionate was also tested and showed oxygen uptake only with the Gram-negative micro-organism, Neisseria subflava; acetate showed none or almost none with all of the examined bacteria. Where oxygen consumption occurred with the various pure or mixed cultures and substrates tested, the quantities of oxygen consumed were less than theoretically possible. For example, they ranged on average in the sediment results from 1.78 mumol oxygen per mumol of L(+)-lactate catabolized to 5.17 mumol oxygen per mumol of lactose. This was consistent with substrate oxidation by the oral bacteria being less than complete as in aerobic glycolysis, and with compounds other than water and carbon dioxide (such as acetate) being prominent amongst the end-products produced. The pure-culture oxygen data and other reports from this laboratory have made it possible to propose a speculative scheme as to which bacterial species might be involved in the various metabolic pathways used when different substrates are catabolized and oxidized by the mixed bacteria in salivary sediment or dental plaque. Also, it made it possible to suggest which bacteria and substrates are likely to be involved in the oxygen depletion that enables plaque to achieve anaerobiosis. PMID:9031704

Traudt, M; Kleinberg, I

1996-10-01

384

Rates of net assimilation and respiration of amino acids by marine bacteria  

Microsoft Academic Search

The selectivity of amino acid assimilation by marine bacteria was examined using seven kinds of14C-amino acids and the acid hydrolysate of14C-labelled proteins. It was found that the net assimilation and respiration by marine bacteria followed MICHAELIS-MENTEN kinetics for all of amino acids used in our experiments. Maximum velocities of amino acids were 0.01 to 0.19?g carbon\\/hour per 2×107 cells for

Yoshiaki Maita; Mitsuru Yanada; Akira Rikuta

1974-01-01

385

[Effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca].  

PubMed

To get the tolerability and consumption of Klebsiella oxytoca on major inhibitors in lignocelluloses hydrolysate, we studied the effect of acetic acid, furfural and 5-hydroxymethylfurfural on production of 2,3-butanediol by Klebsiella oxytoca. The metabolites of furfural and 5-hydroxymethylfurfural were measured. The results show that when acetic acid, furfural and 5-hydroxymethylfurfural was individually added, tolerance threshold for Klebsiella oxytoca was 30 g/L, 4 g/L and 5 g/L, respectively. Acetic acid was likely used as substrate to produce 2,3-butanediol. The yield of 2,3-butanediol increased when acetic acid concentration was lower than 30 g/L. In the fermentation, more than 70% 5-hydroxymethylfurfural was converted to 2,5-furandimethanol. All furfural and the rest of 5-hydroxymethylfurfural were metabolized by Klebsiella oxytoca. It showed that in the detoxification process of 2,3-butanediol production using lignocelluloses hydrolysate, furfural should be given priority to remove and a certain concentration of acetic acid is not need to removal. PMID:23789276

Wu, Jing; Cheng, Keke; Li, Wenying; Feng, Jie; Zhang, Jian'an

2013-03-01

386

Broad and complex antifungal activity among environmental isolates of lactic acid bacteria.  

PubMed

More than 1200 isolates of lactic acid bacteria isolated from different environments were screened for antifungal activity in a dual-culture agar plate assay. Approximately 10% of the isolates showed inhibitory activity and 4% showed strong activity against the indicator mould Aspergillus fumigatus. The antifungal spectra for 37 isolates with strong activity and five isolates with low or no activity were determined. Several of the strains showed strong inhibitory activity against the moulds A. fumigatus, Aspergillus nidulans, Penicillium commune and Fusarium sporotrichioides, and also against the yeast Rhodotorula mucilaginosa. Penicillium roqueforti and the yeasts Pichia anomala and Kluyveromyces marxianus were not inhibited. Several isolates showed reduced antifungal activity after storage and handling. The majority of the fungal inhibitory isolates were identified by 16S rDNA sequencing as Lactobacillus coryniformis. Lactobacillus plantarum and Pediococcus pentosaceus were also frequently identified among the active isolates. The degree of fungal inhibition was not only related to production of lactic or acetic acid. In addition, antifungal cyclic dipeptides were identified after HPLC separation and several other active fractions were found suggesting a highly complex nature of the antifungal activity. PMID:12594034

Magnusson, Jesper; Ström, Katrin; Roos, Stefan; Sjögren, Jörgen; Schnürer, Johan

2003-02-14

387

A Comparison of Two Methods Used for Measuring Antagonistic Activity of Lactic Acid Bacteria  

Microsoft Academic Search

2 Abstract: In this research, we have aimed to determine antagonistic effects of various lactic acid bacteria against Gram (+) and Gram (-) bacteria with a comparison of disc diffusion and spot-on-lawn method. In spot-on-lawn method, P. aeruginosa ATCC 27853 was the most sensitive of the tested bacteria, followed by E. coli ATCC 25927 and P. aeruginosa ATCC 10145. On

Bilge Hilal Cadirci; Sumru Citak

2005-01-01

388

Lactic acid bacteria as adjuvants for sublingual allergy vaccines.  

PubMed

We compared immunomodulatory properties of 11 strains of lactic acid bacteria as well as their capacity to enhance sublingual immunotherapy efficacy in a murine asthma model. Two types of bacterial strains were identified, including: (i) potent inducers of IL-12p70 and IL-10 in dendritic cells, supporting IFN-gamma and IL-10 production in CD4+ T cells such as Lactobacillus helveticus; (ii) pure Th1 inducers such as L. casei. Sublingual administration in ovalbumin-sensitized mice of L. helveticus, but not L. casei, reduced airways hyperresponsiveness, bronchial inflammation and proliferation of specific T cells in cervical lymph nodes. Thus, probiotics acting as a Th1/possibly Treg, but not Th1 adjuvant, potentiate tolerance induction via the sublingual route. PMID:20175969

Van Overtvelt, Laurence; Moussu, Helene; Horiot, Stéphane; Samson, Sandrine; Lombardi, Vincent; Mascarell, Laurent; van de Moer, Ariane; Bourdet-Sicard, Raphaëlle; Moingeon, Philippe

2010-04-01

389

Biomonitoring of 2-(2-alkoxyethoxy)ethanols by analysing urinary 2-(2-alkoxyethoxy)acetic acids.  

PubMed

2-Methoxyacetic and 2-ethoxyacetic acids are well known toxic metabolites of 2-alkoxyethanols. The use of 2-alkoxyethanols is now restricted, and the regulations have forced manufacturers to find substitutive solvents, 2-(2-alkoxyethoxy)ethanols. 2-(2-Alkoxyethoxy)ethanols resemble 2-alkoxyethanols, and their most hazardous similarity is their ability to metabolize to the 2-(2-alkoxyethoxy)acetic acids. In the present study, floor lacquerers' (n = 22) inhalation and total exposure to 2-(2-alkoxy)ethoxyethanols was measured. The measurements of inhalation exposure were done with charcoal tubes, and total exposure was biomonitored by urinalysis of 2-(2-alkoxyethoxy)acetic acids. The 8h inhalation exposures of floor lacquerers to 2-(2-methoxyethoxy)ethanol (DEGME), 2-(2-ethoxyethoxy)ethanol (DEGEE) and 2-(2-butoxyethoxy)ethanol (DEGBE) were in average 0.23 +/- 0.07 ppm (average+/-S.D., n = 3), 0.08 +/- 0.07 ppm (n = 16), and 0.05 +/- 0.03 ppm (n = 16), respectively. The excretions of 2-(2-methoxyethoxy)acetic acid (MEAA), 2-(2-ethoxyethoxy)acetic acid (EEAA) and 2-(2-butoxyethoxy)acetic acid (BEAA) were in average 4.9 +/- 4.3 mmol/mol creatinine, 9.3 +/- 8.0 mmol/mol creatinine and 9.2 +/- 7.4 mmol/mol creatinine, respectively. A linear relationship was found between the urinary 2-(2-alkoxyethoxy)acetic acid concentrations and the preceding 8-h occupational exposure to 2-(2-alkoxyethoxy)ethanol. PMID:15705492

Laitinen, J; Pulkkinen, J

2005-03-28

390

Production of ?-Amino Butyric Acid in Tea Leaves wit Treatment of Lactic Acid Bacteria  

NASA Astrophysics Data System (ADS)

Lactic acid bacteria was searched for producing termented tea that contained a lot of ?-amino butyric acid(GABA). Also examined were the growth condition, GABA production and changes in catechin contents in the tea leaves. Lactobacillus brevis L12 was found to be suitable for the production of fermented tea since it gave as much GABA as gabaron tea when tea leaves being suspended with water at 10% and incubated for 4 days at 25°C. The amount of GABA produced was more than calculated based upon the content of glutamic acid in tea leaves. It is probable to assume that glutamate derived from glutamine and theanine is converted into GABA.

Watanabe, Yuko; Hayakawa, Kiyoshi; Ueno, Hiroshi

391

Hydrogen production from steam reforming of acetic acid over Cu-Zn supported calcium aluminate.  

PubMed

Hydrogen can be produced by catalytic steam reforming (CSR) of biomass-derived oil. Typically bio oil contains 12-14% acetic acid; therefore, this acid was chosen as model compound for reforming of biooil with the help of a Cu-Zn/Ca-Al catalyst for high yield of H(2) with low CH(4) and CO content. Calcium aluminate support was prepared by solid-solid reaction at 1350°C. X-ray diffraction indicates 12CaO·7Al(2)O(3) as major, CaA(l4)O(7) and Ca(5)A(l6)O(14) as minor phases. Cu and Zn were loaded onto the support by wet-impregnation at 10 and 1wt.%, respectively. The catalysts were characterized by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy TEM and the surface area for both support and Cu-Zn were 10.5 and 5.8m(2)/g, respectively. CSR was carried out in a tubular fixed bed reactor (I.D.=19mm) at temperatures between 600 and 800°C with 3-g loadings and (H(2)O/acetic acid) wt. ratio of 9:1. Significantly high (80%) yield of hydrogen was obtained over Cu-Zn/Ca-Al catalyst, as incorporation of Zn enhanced the H(2) yield by reducing deactivation of the catalyst. The coke formation on the support (Ca-12/Al-7) surface was negligible due to the presence of excess oxygen in the 12CaO·7Al(2)O(3) phase. PMID:22944490

Mohanty, Pravakar; Patel, Madhumita; Pant, Kamal K

2012-11-01

392

Azospirillum brasilense Produces the Auxin-Like Phenylacetic Acid by Using the Key Enzyme for Indole-3-Acetic Acid Biosynthesis  

PubMed Central

An antimicrobial compound was isolated from Azospirillum brasilense culture extracts by high-performance liquid chromatography and further identified by gas chromatography-mass spectrometry as the auxin-like molecule, phenylacetic acid (PAA). PAA synthesis was found to be mediated by the indole-3-pyruvate decarboxylase, previously identified as a key enzyme in indole-3-acetic acid (IAA) production in A. brasilense. In minimal growth medium, PAA biosynthesis by A. brasilense was only observed in the presence of phenylalanine (or precursors thereof). This observation suggests deamination of phenylalanine, decarboxylation of phenylpyruvate, and subsequent oxidation of phenylacetaldehyde as the most likely pathway for PAA synthesis. Expression analysis revealed that transcription of the ipdC gene is upregulated by PAA, as was previously described for IAA and synthetic auxins, indicating a positive feedback regulation. The synthesis of PAA by A. brasilense is discussed in relation to previously reported biocontrol properties of A. brasilense.

Somers, E.; Ptacek, D.; Gysegom, P.; Srinivasan, M.; Vanderleyden, J.

2005-01-01

393

Engineering efficient xylose metabolism into an acetic acid-tolerant Zymomonas mobilis strain by introducing adaptation-induced mutations.  

PubMed

The impact of the two adaptation-induced mutations in an improved xylose-fermenting Zymomonas mobilis strain was investigated. The chromosomal mutation at the xylose reductase gene was critical to xylose metabolism by reducing xylitol formation. Together with the plasmid-borne mutation impacting xylose isomerase activity, these two mutations accounted for 80 % of the improvement achieved by adaptation. To generate a strain fermenting xylose in the presence of high acetic acid concentrations, we transferred the two mutations to an acetic acid-tolerant strain. The resulting strain fermented glucose + xylose (each at 5 % w/v) with 1 % (w/v) acetic acid at pH 5.8 to completion with an ethanol yield of 93.4 %, outperforming other reported strains. This work demonstrated the power of applying molecular understanding in strain improvement. PMID:22669340

Agrawal, Manoj; Wang, Yun; Chen, Rachel Ruizhen

2012-10-01

394

Metal-organic coordination architectures of azole heterocycle ligands bearing acetic acid groups: Synthesis, structure and magnetic properties  

NASA Astrophysics Data System (ADS)

Four new coordination complexes with azole heterocycle ligands bearing acetic acid groups, [Co( L1) 2] n ( 1) , [Cu L1N 3] n ( 2), [Cu( L2) 2·0.5C 2H 5OH·H 2O] n ( 3) and [Co( L2) 2] n ( 4) (here, H L1=1H-imidazole-1-yl-acetic acid, H L2=1H-benzimidazole-1-yl-acetic acid) have been synthesized and structurally characterized. Single-crystal structure analysis shows that 3 and 4 are 2D complexes with 4 4-sql topologies, while another 2D complex 1 has a (4 3) 2(4 6)-kgd topology. And 2 is a 3D complex composed dinuclear ?1,1-bridging azido Cu II entities with distorted rutile topology. The magnetic properties of 1 and 2 have been studied.

Hu, Bo-Wen; Zhao, Jiong-Peng; Yang, Qian; Hu, Tong-Liang; Du, Wen-Ping; Bu, Xian-He

2009-10-01

395

Amino acid profiles of lactic acid bacteria, isolated from kefir grains and kefir starter made from them  

Microsoft Academic Search

The characteristics of cell growth, lactic acid production, amino acid release and consumption by single-strain cultures of lactic acid bacteria (isolated from kefir grains), and by a multiple-strain kefir starter prepared from them, were studied. The change in the levels of free amino acids was followed throughout the kefir process: single-strain kefir bacteria and the kefir starter (Lactococcus lactis C15–1%+Lactobacillus

Emilina Simova; Zhelyasko Simov; Dora Beshkova; Ginka Frengova; Zhechko Dimitrov; Zdravko Spasov

2006-01-01

396

Native lignin structure of Miscanthus x giganteus and its changes during acetic and formic acid fractionation.  

PubMed

Milled wood lignin (MWL) and acetic and formic acid lignin (AL and FL) from Miscanthus x giganteus bark were produced, respectively, before and after organosolv fractionations under optimal conditions, in terms of organic and hydrochloric acid concentrations, liquid/wood ratio, and reaction time. In order to study the M. x giganteus native lignin structure and its modifications during the fractionation process, the lignins were studied by two-dimensional heteronuclear single quantum coherence (2D-(HSQC)), (13)C- and (31)P nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR), size-exclusion chromatography (SEC) both before and after thioacidolysis, and elemental analysis. In addition, chemical composition analysis was performed on ash, Klason lignin, and carbohydrate content. The analyses demonstrated that M. x giganteus native lignin (MWL) is highly acylated at the C(gamma) of the lignin side chain (46%), possibly with p-coumarate and/or acetate groups. This is newsworthy since several earlier studies showed that acylation at the gamma-carbon commonly occurs in C(3) and CAM grasses, whereas M. x giganteus is a C(4) grass. Furthermore, M. x giganteus showed a low S/G ratio (0.7) and a predominance of beta-O-4' linkages (up to 93% of all linkages). AL and FL lose part of these linkages during organosolv fractionation (up to 21 and 32%, respectively). The p-coumarate groups resist fractionation processes and are still present in high quantities in AL and FL. During the fractionation process, lignin is acetylated (acetic acid process) and condensed, with the G units condensing more than S units. M. x giganteus MWL contains a high content of carbohydrates (22.8%), suggesting that it is a lignin-carbohydrate complex (LCC). AL and FL showed low carbohydrate contents because of the breaking down of the LCC structures. AL and FL have high molecular weights and low polydispersities, and are high in phenolic content, qualities that make these suitable for different applications. These results suggest that refinement of M. x giganteus via organosolv processes could potentially turn this grass into a valuable source of both fiber and lignin. PMID:19552425

Villaverde, Juan José; Li, Jiebing; Ek, Monica; Ligero, Pablo; de Vega, Alberto

2009-07-22

397

Suppressing glucose uptake and acetic acid production increases membrane protein overexpression in Escherichia coli  

PubMed Central

Background The production of integral membrane spanning proteins (IMP's) constitutes a bottleneck in pharmaceutical development. It was long considered that the state-of-the-art was to produce the proteins as inclusion bodies using a powerful induction system. However, the quality of the protein was compromised and the production of a soluble protein that is incorporated into the membrane from which it is extracted is now considered to be a better method. Earlier research has indicated that a slower rate of protein synthesis might overcome the tendency to form inclusion bodies. We here suggest the use of a set of E. coli mutants characterized by a slower rate of growth and protein synthesis as a tool for increasing the amount of soluble protein in high- throughput protein production processes. Results A set of five IMP's was chosen which were expressed in three mutants and the corresponding WT cell (control). The mutations led to three different substrate uptake rates, two of which were considerably slower than that of the wild type. Using the mutants, we were able to express three out of the five membrane proteins. Most successful was the mutant growing at 50% of the wild type growth rate. A further effect of a low growth rate is a low acetic acid formation, and we believe that this is a possible reason for the better production. This hypothesis was further supported by expression from the BL21(DE3) strain, using the same plasmid. This strain grows at a high growth rate but nevertheless yields only small amounts of acetic acid. This strain was also able to express three out of the five IMP's, although at lower quantities. Conclusions The use of mutants that reduce the specific substrate uptake rate seems to be a versatile tool for overcoming some of the difficulties in the production of integral membrane spanning proteins. A set of strains with mutations in the glucose uptake system and with a lower acetic acid formation were able to produce three out of five membrane proteins that it was not possible to produce with the corresponding wild type.

2011-01-01

398

The use of acetic acid as a source of carbon by cultured Chondrus crispus (Gigartinales, Rhodophyta) stackhouse  

Microsoft Academic Search

When growing seaweeds in tanks, pH and carbon source supply have to be controlled in order to maximize photosynthesis. pH can be controlled either by adding various inorganic acids which requires the extra addition of carbon, or by combining pH control and carbon source with for instance CO2 or an organic acid such as acetic acid (CH3COOH). We have found

Mireille A. Amat; Jean-Paul Braud

1993-01-01

399

Bio-available amino acids extraction from soil by demineralized water and 0.5 M ammonium acetate.  

PubMed

The extraction and comparison of soil bio-available amino acids using either demineralised water (DEMI H(2)O) or 0.5 M ammonium acetate (0.5 M AAc) solution is reported. Results show that the extraction by 0.5 M AAc is a better method to assess the concentration of bio-available amino acids in soil than DEMI H(2)O due to higher extraction efficiency and better amino acid protection against microbial degradation during processing. PMID:15838591

Formánek, P; Klejdus, B; Vranová, V

2005-06-01

400

Study of polydimethylsiloxane/aromatic polyamide laminated membranes for separation of acetic acid/water mixtures by pervaporation process  

SciTech Connect

Separation of acetic acid/water mixtures by pervaporation was attempted over a range of compositions using polydimethylsiloxane (PDMS), aromatic polyamide (PA), and laminated polydimethylsiloxane-aromatic polyamide membranes. PDMS membranes are hydrophobic and acetic acid selective, whereas PA membranes are hydrophilic and water selective. When PDMS and PA membranes were laminated, with PDMS on the top side and in contact with the feed, water selectivity of the bottom PA membrane was intensified. On the other hand, when the PA membrane was on the top side and in contact with the feed, the selectivity was lowered. 10 refs., 4 figs.

Deng, S.; Sourirajan, S.; Matsuura, T. (Univ. of Ottawa (Canada))

1994-06-01

401

Isotopic composition of Murchison organic compounds: Intramolecular carbon isotope fractionation of acetic acid. Simulation studies of cosmochemical organic syntheses  

NASA Technical Reports Server (NTRS)

Recently, in our laboratories, samples of Murchison acetic acid were decarboxylated successfully and the carbon isotopic composition was measured for the methane released by this procedure. These analyses showed significant differences in C-13/C-12 ratios for the methyl and carboxyl carbons of the acetic acid molecule, strongly suggesting that more than one carbon source may be involved in the synthesis of the Murchison organic compounds. On the basis of this finding, laboratory model systems simulating cosmochemical synthesis are being studied, especially those processes capable of involving two or more starting carbon sources.

Yuen, G. U.; Cronin, J. R.; Blair, N. E.; Desmarais, D. J.; Chang, S.

1991-01-01

402

Continuous cultivation of photosynthetic bacteria for fatty acids production.  

PubMed

In the present work, we introduced a novel approach for microbial fatty acids (FA) production. Photosynthetic bacteria, Rhodobacter sphaeroides KD131, were cultivated in a continuous-flow, stirred-tank reactor (CFSTR) at various substrate (lactate) concentrations. At hydraulic retention time (HRT) 4d, cell concentration continuously increased from 0.97 g dcw/L to 2.05 g dcw/L as lactate concentration increased from 30 mM to 60mM. At 70 mM, however, cell concentration fluctuated with incomplete substrate degradation. By installing a membrane unit to CFSTR, a stable performance was observed under much higher substrate loading (lactate 100mM and HRT 1.5d). A maximum cell concentration of 16.2g dcw/L, cell productivity of 1.9 g dcw/L/d, and FA productivity of 665 mg FA/L/d were attained, and these values were comparable with those achieved using microalgae. The FA content of R. sphaeroides was around 35% of dry cell weight, mainly composed of vaccenic acid (C18:1, omega-7). PMID:24055970

Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon; Kang, Seoktae; Kim, Mi-Sun

2013-11-01

403

One-component thioxanthone acetic acid derivative photoinitiator for free radical polymerization.  

PubMed

Acetic acid-based thioxanthone (TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate (MMA) in the absence and presence of a tertiary amine (MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses ?-?* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 ?s at 630 nm. PMID:24372104

Esen, Duygu S; Temel, Gokhan; Balta, Demet K; Allonas, Xavier; Arsu, Nergis

2014-01-01

404

Photoinduced excited state proton rearrangement of 6-hydroxyquinoline along a hydrogen-bonded acetic acid wire  

NASA Astrophysics Data System (ADS)

6-Hydroxyquinoline (6-HQ) in benzene emits normal fluorescence around 357 nm. In the presence of acetic acid (HOAc), it exhibits two more bands at ˜419 nm and a large Stokes shifted one at ˜583 nm with decreased intensity of the normal fluorescence. It appears to form (1:1) and (1:2) complexes-(1:2) 6-HQ/HOAc undergoes an excited state proton rearrangement ( via HOAc wire) resulting in keto tautomer (emitting at ˜583 nm). This appears to be in line with recent findings where ammonia wires facilitate proton/hydrogen translocation (Science, 302, 1736, 2003). However, (1:1) 6-HQ/HOAc exhibits intermediate emission (˜419 nm) presumably due to ESIPT.

Mehata, Mohan Singh

2007-03-01

405

[Effect of detergents on the hydroxylation of indolyl-3-acetic acid by an Aspergillus niger culture].  

PubMed

A possibility to increase the hydroxylating activity of Aspergillus niger IBFM F-212 under the action of detergents was studied during transformation of indolyl-3-acetic acid (IAA). The following non-ionogenic surface-active compounds were mainly used: Tweens, Spans, polyethyleneglycol (PEG-400). The effect of the detergents was studied at the stages of growth, transformation and preincubation. At the stage of growth, the best effect was produced by Tween-80. At the stages of transformation and preincubation, the hydroxylating activity increased 1.5 times under the action of a number of Spans and PEG-400. No total positive effect of the detergents on the enzyme activity was found at the stages of growth and transformation. The results suggest that the cellular permeability changes under the action of detergents and the hydroxylating activity of the culture increases as the result. PMID:7412617

Baklashova, T G; Koshcheenko, K A

1980-01-01

406

Liquid-liquid equilibria of the ternary system water + acetic acid + 2-methyl-2-butanol  

SciTech Connect

Liquid-liquid equilibria for the ternary system water + acetic acid + 2-methyl-2-butanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UJNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. The UNIFAC model satisfactorily predicted the equilibrium compositions.

Fahim, M.A.; Al-Muhtaseb, S.A. [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1996-11-01

407

Electron transport chains of lactic acid bacteria - walking on crutches is part of their lifestyle  

PubMed Central

A variety of lactic acid bacteria contain rudimentary electron transport chains that can be reconstituted by the addition of heme and menaquinone to the growth medium. These activated electron transport chains lead to higher biomass production and increased robustness, which is beneficial for industrial applications, but a major concern when dealing with pathogenic lactic acid bacteria.

Brooijmans, Rob; Hugenholtz, Jeroen

2009-01-01

408

Lactic acid bacteria in the quality improvement and depreciation of wine  

Microsoft Academic Search

The winemaking process includes two main steps: lactic acid bacteria are responsible for the malolactic fermentation which follows the alcoholic fermentation by yeasts. Both types of microorganisms are present on grapes and on cellar equipment. Yeasts are better adapted to growth in grape must than lactic acid bacteria, so the alcoholic fermentation starts quickly. In must, up to ten lactic

Aline Lonvaud-Funel

1999-01-01

409

Lactic acid bacteria as functional starter cultures for the food fermentation industry  

Microsoft Academic Search

The production of fermented foods is based on the use of starter cultures, for instance lactic acid bacteria that initiate rapid acidification of the raw material. Recently, new starter cultures of lactic acid bacteria with an industrially important functionality are being developed. The latter can contribute to the microbial safety or offer one or more organoleptic, technological, nutritional, or health

Frédéric Leroy; Luc De Vuyst

2004-01-01

410

Potential of phenolic compounds for controlling lactic acid bacteria growth in wine  

Microsoft Academic Search

Lactic acid bacteria are important in enology since they undergo the malolactic fermentation, a process which main effect is the reduction of wine acidity and is almost indispensable in red wine-making. However, if this process is not well controlled during the elaboration of wine, alterations in wine quality due to bacteria metabolic activity can happen. Polyphenols are wine natural components

A. García-Ruiz; B. Bartolomé; A. J. Martínez-Rodríguez; E. Pueyo; P. J. Martín-Álvarez; M. V. Moreno-Arribas

2008-01-01

411

Improving the Quality of Fermented Camel Sausage by Controlling Undesirable Microorganisms with Selected Lactic Acid Bacteria  

Microsoft Academic Search

Main objectives of the present work was to study the possibility of preserving ground camel meat by a biological procedure using lactic acid bacteria to encourage an extended shelf-life of fresh meat in hot areas. Lactic acid bacteria isolated from natural fermented foodstuffs were selected for their antimicrobial activity, and used in sausage making from camel meat. Fresh meat purchased

I. KALALOU; M. FAID; T. A. AHAMI

412

Screening of species-specific lactic acid bacteria for veal calves multi-strain probiotic adjuncts  

Microsoft Academic Search

The selection of promising specific species of lactic acid bacteria with potential probiotic characteristics is of particular interest in producing multi species-specific probiotic adjuncts in veal calves rearing. The aim of the present work was to select and evaluate in vitro the functional activity of lactic acid bacteria, Bifidobacterium longum and Bacillus coagulans strains isolated from veal calves in order to

Barbara Ripamonti; Alessandro Agazzi; Carla Bersani; Paola De Dea; Chiara Pecorini; Silvia Pirani; Raffaella Rebucci; Giovanni Savoini; Simone Stella; Alberta Stenico; Erica Tirloni; Cinzia Domeneghini

2011-01-01

413

THE USE OF ACETIC ACID IONTOPHORESIS IN THE MANAGEMENT OF A SOFT TISSUE INJURY  

PubMed Central

Background: Contusions are common injuries that occur in athletics. If repeated, complications like myositis ossificans can occur. This case describes the examination and treatment of an athlete with an acute soft tissue injury. Objective: To describe the treatment approach used with a hockey player who sustained a soft tissue injury in his upper extremity. Case Description: A 19 year old male sustained a soft tissue injury to his upper arm while playing hockey. The athlete complained of pain rated a 2-3 out of 10. He had a well circumscribed, firm, 8 by 5 centimeter palpable mass present along the lateral arm, and was able to passively flex his elbow from 56° to 135°, demonstrating a 56° loss of elbow extension. Functionally, he was able to perform most activities of daily living, but he was unable to play hockey. Over 29 days, the athlete was treated one time with pulsed ultrasound and ice and nine times with iontophoresis using a 2% acetic acid solution. Additionally, the athlete performed pain-free active range of motion exercises for the elbow. Outcome: Following treatment, the athlete's pain resolved, the palpable mass disappeared, and his passive range of motion at the elbow was 0° to 135°. Most importantly, the athlete was able to resume playing hockey. Discussion: Acetic acid iontophoresis may be a successful intervention for soft tissue injuries of the upper extremity. In this case, it appeared helpful in decreasing the athlete's impairments and contributed to quicker resumption of all functional activities in less time than previously reported in the literature using traditional treatment interventions.

Ebaugh, David

2010-01-01

414

Pickled egg production: effect of brine acetic Acid concentration and packing conditions on acidification rate.  

PubMed

U.S. federal regulations require that acidified foods must reach a pH of 4.6 or lower within 24 h of packaging or be kept refrigerated until then. Processes and formulations should be designed to satisfy this requirement, unless proper studies demonstrate the safety of other conditions. Our objective was to determine the effect of brine acetic acid concentration and packing conditions on the acidification rate of hard-boiled eggs. Eggs were acidified (60/40 egg-to-brine ratio) at various conditions of brine temperature, heat treatment to filled jars, and postpacking temperature: (i) 25°C/none/25°C (cold fill), (ii) 25°C/none/2°C (cold fill/refrigerated), (iii) 85°C/none/25°C (hot fill), and (iv) 25°C/100°C for 16 min/25°C (water bath). Three brine concentrations were evaluated (7.5, 4.9, and 2.5% acetic acid) and egg pH values (whole, yolk, four points within egg) were measured from 4 to 144 h, with eggs equilibrating at pH 3.8, 4.0, and 4.3, respectively. Experiments were conducted in triplicate, and effects were considered significant when P < 0.05. Multiple linear regression analysis was conducted to evaluate the effect on pH values at the center of the yolk. Regression analysis showed that brine concentration of 2.5% decreased the acidification rate, while packing conditions of the hot fill trial increased it. Inverse prediction was used to determine the time for the center of the yolk and the total yolk to reach a pH value of 4.6. These results demonstrate the importance of conducting acidification studies with proper pH measurements to determine safe conditions to manufacture commercially stable pickled eggs. PMID:24780334

Acosta, Oscar; Gao, Xiaofan; Sullivan, Elizabeth K; Padilla-Zakour, Olga I

2014-05-01

415

Comparison of the high-pressure and low-temperature structures of ethanol and acetic acid  

NASA Astrophysics Data System (ADS)

We have determined the high-pressure crystal structures of ethanol and acetic acid, including the positions of the hydrogen atoms, using a combination of single-crystal x-ray-diffraction techniques and ab initio pseudopotential calculations. We find that in the high-pressure structure of ethanol the molecules are arranged in infinite hydrogen-bonded chains that adopt a structural conformation that is distinctly different from that of the low-temperature form. The hydrogen-bond lengths and bond angles within the chains are equal by symmetry and, as the molecules also have an alternating alignment to the chains, the molecular chains are relatively unstrained. It is proposed that this uniformity and lack of strain within the chains enables ethanol to crystallize much more readily than methanol at high pressure. For acetic acid we find that the molecules are also arranged in infinite hydrogen-bonded chains that are essentially identical to those in the low-temperature structure. However, they adopt markedly different relative orientations, which leads to a more efficient molecular packing and a radically different methyl-methyl contact motif between adjacent molecular chains. The calculated enthalpies of the high-pressure and low-temperature structures show that the high-pressure phase is the most energetically favorable. We find a relatively small 0.056 eV/molecule enthalpy difference between the two structures and this is reflected in the very low freezing pressure of approximately 0.2 GPa at room temperature compared to the freezing temperature of 16 °C at ambient pressure.

Allan, David R.; Clark, Stewart J.

1999-09-01

416

Effect of lactic acid bacteria on growth of Staphylococcus aureus.  

PubMed

Cultures of lactic acid bacteria, mostly from foods, were tested for their effect on the growth of Staphylococcus aureus in Trypticase Soy Broth (BBL). Some of the effectors, e.g., Streptococcus faecalis, S. faecium, Lactobacillus lactis, L. brevis, and Leuconostoc mesenteroides, stimulated growth of S. aureus during early hours of growth, especially at higher temperatures of incubation, but most cultures were inhibitory, and some (S. faecium and L. mesenteroides) were even killing by the time of attainment of the maximal phase of growth of the Staphylococcus. Low-temperature meat lactobacilli and Leuconostoc dextranicum inhibited S. aureus at 10, 15, 20, and 25 C throughout its growth. Streptococcus faecalis var. liquefaciens inhibited at these temperatures and at 30 and 37 C, as well. When the ratio of effectors to staphylococci in the inoculum was 100:1, the three enterococci, the meat Lactobacillus, and L. dextranicum prevented the attainment of 5 x 10(6) staphylococci per milliliter at 15 C, and all but the meat Lactobacillus did so at 22 C. A ratio of 1:1 accomplished similar results at 15 C, except that S. aureus was only delayed for 12 hr by S. faecalis. A ratio of 1:100 usually was ineffective. In general, the more effector bacteria there were in the inoculum, the greater was the overall inhibition (or stimulation) of S. aureus. Inhibition was most effective at 10 or 15 C, less so at 20 or 25 C, and least at 30 or 37 C, whereas stimulation during early growth was greater at the higher temperatures. Results with different strains of the effectors and with two strains of S. aureus were similar, for the most part. PMID:4959983

Kao, C T; Frazier, W C

1966-03-01

417

Enhancement of organic solar cells efficiency with acetic acid modulated poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) buffer layers.  

PubMed

Bulk-heterojunction organic solar cells (OSCs) based on poly(3-hexylthiophene) as a donor material and (6.6) phenyl-C61-butyric acid methyl ester as an acceptor material were investigated using a poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) buffer layer that was modulated with acetic acid. The 1.71 x 10(-1) omega x cm resistivity of the pristine PEDOT:PSS film decreased to 2.29 x 10(-2) omega x cm when acetic acid was applied. This modified PEDOT:PSS buffer layer improved the power conversion efficiency (PCE) of OSCs by reducing their already low series resistance and contact resistance. The PCE of OSCs in which the PEDOT:PSS buffer layers had been treated with acetic acid was 2.91%, an improvement over the 1.82% PCE for cells with pristine PEDOT:PSS layers. We optimized the ratio of acetic acid and PEDOT:PSS solution for high PCE of OSCs in this manuscript. The value of this modification method for hole transporting layer is clearly demonstrated and be applicable to other organic devices. PMID:24758027

Oh, Sang Hoon; Heo, Seung Jin; Kim, Hyun Jae

2014-07-01

418

Diversity of human colonic butyrate-producing bacteria revealed by analysis of the butyryl-CoA:acetate CoA-transferase gene.  

PubMed

Butyrate-producing bacteria play an important role in the human colon, supplying energy to the gut epithelium and regulating host cell responses. In order to explore the diversity and culturability of this functional group, we designed degenerate primers to amplify butyryl-CoA:acetate CoA-transferase sequences from faecal samples provided by 10 healthy volunteers. Eighty-eight per cent of amplified sequences showed >98% DNA sequence identity to CoA-transferases from cultured butyrate-producing bacteria, and these fell into 12 operational taxonomic units (OTUs). The four most prevalent OTUs corresponded to Eubacterium rectale, Roseburia faecis, Eubacterium hallii and an unnamed cultured species SS2/1. The remaining 12% of sequences, however, belonged to 20 OTUs that are assumed to come from uncultured butyrate-producing strains. Samples taken after ingestion of inulin showed significant (P=0.019) increases in Faecalibacterium prausnitzii. Because several of the dominant butyrate producers differ in their DNA % G+C content, analysis of thermal melt curves obtained for PCR amplicons of the butyryl-CoA:acetate CoA-transferase gene provides a convenient and rapid qualitative assessment of the major butyrate producing groups present in a given sample. This type of analysis therefore provides an excellent source of information on functionally important groups within the colonic microbial community. PMID:19807780

Louis, Petra; Young, Pauline; Holtrop, Grietje; Flint, Harry J

2010-02-01

419

Selective activation of vitamin D receptor by lithocholic acid acetate, a bile acid derivative  

Microsoft Academic Search

The vitamin D receptor (VDR), a member of the nuclear receptor superfamily, mediates the biological ac- tions of the active form of vitamin D, 1 ? ,25-dihydroxyvita- min D 3 . It regulates calcium homeostasis, immunity, cellular differentiation, and other physiological processes. Recently, VDR was found to respond to bile acids as well as other nu- clear receptors, farnesoid X

Ryutaro Adachi; Yoshio Honma; Hiroyuki Masuno; Katsuyoshi Kawana; Iichiro Shimomura; Sachiko Yamada; Makoto Makishima

2004-01-01

420

Mannitol production by lactic acid bacteria grown in supplemented carob syrup.  

PubMed

Detailed kinetic and physiological characterisation of eight mannitol-producing lactic acid bacteria, Leuconostoc citreum ATCC 49370, L. mesenteroides subsp. cremoris ATCC19254, L. mesenteroides subsp. dextranicum ATCC 19255, L. ficulneum NRRL B-23447, L. fructosum NRRL B-2041, L. lactis ATCC 19256, Lactobacillus intermedius NRRL 3692 and Lb. reuteri DSM 20016, was performed using a carob-based culture medium, to evaluate their different metabolic capabilities. Cultures were thoroughly followed for 30 h to evaluate consumption of sugars, as well as production of biomass and metabolites. All strains produced mannitol at high yields (>0.70 g mannitol/g fructose) and volumetric productivities (>1.31 g/l h), and consumed fructose and glucose simultaneously, but fructose assimilation rate was always higher. The results obtained enable the studied strains to be divided mainly into two groups: one for which glucose assimilation rates were below 0.78 g/l h (strains ATCC 49370, ATCC 19256 and ATCC 19254) and the other for which they ranged between 1.41 and 1.89 g/l h (strains NRRL B-3692, NRRL B-2041, NRRL B-23447 and DSM 20016). These groups also exhibited different mannitol production rates and yields, being higher for the strains with faster glucose assimilation. Besides mannitol, all strains also produced lactic acid and acetic acid. The best performance was obtained for L. fructosum NRRL B-2041, with maximum volumetric productivity of 2.36 g/l h and the highest yield, stoichiometric conversion of fructose to mannitol. PMID:20820868

Carvalheiro, Florbela; Moniz, Patrícia; Duarte, Luís C; Esteves, M Paula; Gírio, Francisco M

2011-01-01