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1

Comparison of Dry Medium Culture Plates for Mesophilic Aerobic Bacteria in Milk, Ice Cream, Ham, and Codfish Fillet Products  

PubMed Central

This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products. PMID:24551829

Park, Junghyun; Kim, Myunghee

2013-01-01

2

Comparison of dry medium culture plates for mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products.  

PubMed

This study was performed to compare the performance of Sanita-Kun dry medium culture plate with those of traditional culture medium and Petrifilm dry medium culture plate for the enumeration of the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet. Mesophilic aerobic bacteria were comparatively evaluated in milk, ice cream, ham, and codfish fillet using Sanita-Kun aerobic count (SAC), Petrifilm aerobic count (PAC), and traditional plate count agar (PCA) media. According to the results, all methods showed high correlations of 0.989~1.000 and no significant differences were observed for enumerating the mesophilic aerobic bacteria in the tested food products. SAC method was easier to perform and count colonies efficiently as compared to the PCA and PAC methods. Therefore, we concluded that the SAC method offers an acceptable alternative to the PCA and PAC methods for counting the mesophilic aerobic bacteria in milk, ice cream, ham, and codfish fillet products. PMID:24551829

Park, Junghyun; Kim, Myunghee

2013-12-01

3

Growth parameters of escherichia coli O157:H7, salmonella and listeria monocytogenes and aerobic mesophilic bacteria of apple cider amended with nisin-EDTA  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of nisin (0 or 300 IU), Ethylenediamine Tetraacetic Acid (EDTA, 20 mM) and (nisin 300 IU+ EDTA 20 mM) on growth parameters; including lag period (LP) and growth rate (GR) of Escherichia coli O157:H7, L. monocytogenes and Salmonella spp. in the presence or absence of aerobic mesophilic bac...

4

Effect of chlorine, sodium chloride, trisodium phosphate, and ultraviolet radiation on the reduction of Yersinia enterocolitica and mesophilic aerobic bacteria from eggshell surface.  

PubMed

Eggshell sanitizing practices are necessary to improve microbiological safety of fresh hen eggs and their products. In this work, the effects of 100 mg/liter free chlorine (chl), 3% sodium chloride (NaCl), 1, 5, and 12% trisodium phosphate (TSP) in wash solutions, and UVR (ultraviolet radiation; 4.573 microW/cm2) were studied at different times on uninoculated and Yersinia enterocolitica-inoculated eggs. On uninoculated eggs, the best results were obtained with 100 mg/liter chlorine and UV exposure for >25 min, with reductions of 1.28 and 1.60 log cycles, respectively, compared to the average bacterial count (4.55 log CFU/egg) on the control (untreated eggs). On Y. enterocolitica-inoculated eggs, highest reductions of the average bacterial count (7.35 log CFU/egg) were obtained with 5 and 12% TSP and 100 mg/liter chl. The decrease obtained with 12% TSP (3.74-log reduction) was significantly higher (P < 0.05) than those obtained with the remaining treatments. Y. enterocolitica was more resistant to UVR than the eggshell natural mesophilic aerobic microflora, except when low inoculum (4.39 log CFU/egg) was assayed. Changes in eggshell microstructure were measured by the blue lake staining method. The presence of Yersinia and Salmonella in eggshell natural flora was also investigated. PMID:11601717

Favier, G L; Escudero, M E; de Guzman, A M

2001-10-01

5

Aerobic Anoxygenic Phototrophic Bacteria  

PubMed Central

The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the ?-1, ?-3, and ?-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

Yurkov, Vladimir V.; Beatty, J. Thomas

1998-01-01

6

DESTRUCTION BY ANAEROBIC MESOPHILIC AND THERMOPHILIC DIGESTION OF VIRUSES AND INDICATOR BACTERIA INDIGENOUS TO DOMESTIC SLUDGES  

EPA Science Inventory

In raw sludges and in mesophilically and thermophilically digested anaerobic sludges, large variations in numbers of viruses occurred over narrow ranges of numbers of fecal coliforms, total coliforms, and fecal streptococci, demonstrating that the bacteria are poor quantitative r...

7

Cellulose degradation by one mesophilic strain Caulobacter sp. FMC1 under both aerobic and anaerobic conditions.  

PubMed

Caulobacteria are presumed to be responsible for considerable mineralization of organic material in aquatic environments. In this study, a facultative, mesophilic and cellulolytic bacterium Caulobacter sp. FMC1 was isolated from sediments which were taken from a shallow freshwater lake and then enriched with amendment of submerged macrophyte for three months. This strain seemed to evolve a capacity to adapt redox-fluctuating environments, and could degrade cellulose both aerobically and anaerobically. Cellulose degradation percentages under aerobic and anaerobic conditions were approximately 27% and 10% after a 240-h incubation in liquid mediums containing 0.5% cellulose, respectively. Either cellulose or cellobiose alone was able to induce activities of endoglucanase, exoglucanase, and ?-1,4-glucosidase. Interestingly, ethanol was produced as the main fermentative product under anaerobic incubation on cellulose. These results could improve our understanding about cellulose-degrading process in aquatic environments, and were also useful in optimizing cellulose bioconversion process for bioethanol production. PMID:23357088

Song, Na; Cai, Hai-Yuan; Yan, Zai-Sheng; Jiang, He-Long

2013-03-01

8

[The phylogenetic diversity of aerobic organotrophic bacteria from the Dagan high-temperature oil field].  

PubMed

The distribution and species diversity of aerobic organotrophic bacteria in the Dagan high-temperature oil field (China), which is exploited via flooding, have been studied. Twenty-two strains of the most characteristic thermophilic and mesophilic aerobic organotrophic bacteria have been isolated from the oil stratum. It has been found that, in a laboratory, the mesophilic and thermophilic isolates grow in the temperature, pH, and salinity ranges characteristic of the injection well near-bottom zones or of the oil stratum, respectively, and assimilate a wide range of hydrocarbons, fatty acids, lower alcohols, and crude oil, thus exhibiting adaptation to the environment. Using comparative phylogenetic 16S rRNA analysis, the taxonomic affiliation of the isolates has been established. The aerobic microbial community includes gram-positive bacteria with a high and low G+C content of DNA, and gamma and beta subclasses of Proteobacteria. The thermophilic bacteria belong to the genera Geobacillus and Thermoactinomyces, and the mesophilic strains belong to the genera Bacillus, Micrococcus, Cellulomonas, Pseudomonas, and Acinetobacter. The microbial community of the oil stratum is dominated by known species of the genus Geobacillus (G. subterraneus, G. stearothermophilus, and G. thermoglucosidasius) and a novel species "Geobacillus jurassicus." A number of novel thermophilic oil-oxidizing bacilli have been isolated. PMID:16119855

Nazina, T N; Sokolova, D Sh; Shestakova, N M; Grigor'ian, A A; Mikha?lova, E M; Babich, T L; Lysenko, A M; Turova, T P; Poltaraus, A B; Feng, Tsin'syan; Ni, Fangtian; Beliaev, S S

2005-01-01

9

Isolation of aerobic bacteria from the placenta.  

PubMed

Cultures for aerobic bacteria were prepared from 353 placentas. Specimens were taken from the chorion after removing the amnion. The specimens were immersed into Stuart transport medium. Microscopic examination of the placenta and cultures from the throat and ear of newborns were also done. The rate of positive bacterial cultures was 16%. Chorioamnionitis was found in 15%. The proportion of chorioamnionitis caused by aerobic bacteria was 44%. The rate of positive bacterial cultures from the placenta in the group of newborns with clinical signs of intrauterine infection was 63%. Bacteria can be present on the chorionic plate without any histological evidence of chorioamnionitis. Bacteriological examination of the placenta is therefore mandatory when amniotic fluid infection is suspected. PMID:6817588

Kovalovszki, L; Villįnyi, Z; Pataki, I; Veszelowvsky, I; Nagy, Z B

1982-01-01

10

Comparison of sludge digestion under aerobic and anaerobic conditions with a focus on the degradation of proteins at mesophilic temperature.  

PubMed

Aerobic and anaerobic digestion are popular methods for the treatment of waste activated sludge. However, the differences in degradation of sludge during aerobic and anaerobic digestion remain unclear. In this study, the sludge degradation during aerobic and anaerobic digestion was investigated at mesophilic temperature, focused on protein based on the degradation efficiency and degree of humification. The duration of aerobic and anaerobic digestion was about 90 days. The final degradation efficiency of volatile solid was 66.1 ± 1.6% and 66.4 ± 2.4% under aerobic and anaerobic conditions, respectively. The final degradation efficiency of protein was 67.5 ± 1.4% and 65.1 ± 2.6% under aerobic and anaerobic conditions, respectively. The degradation models of volatile solids were consistent with those of protein under both aerobic and anaerobic conditions. The solubility of protein under aerobic digestion was greater than that under anaerobic digestion. Moreover, the humification index of dissolved organic matter of aerobic digestion was greater than that during anaerobic digestion. PMID:23685650

Shao, Liming; Wang, Tianfeng; Li, Tianshui; Lü, Fan; He, Pinjing

2013-07-01

11

Aerobic culture of anaerobic bacteria using antioxidants: a preliminary report.  

PubMed

Antioxidants have been shown to help the growth of anaerobic bacteria. We were able to grow six anaerobe species (including Fusobacterium necrophorum and Ruminococcus gravus) and seven aerobic species all aerobically in Schaedler agar tubes and agar plates with high doses of ascorbic acid and/or glutathione. This may deeply change strategies for culturing bacteria. PMID:24820294

La Scola, B; Khelaifia, S; Lagier, J-C; Raoult, D

2014-10-01

12

Biology of Moderately Halophilic Aerobic Bacteria  

PubMed Central

The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

Ventosa, Antonio; Nieto, Joaquķn J.; Oren, Aharon

1998-01-01

13

Rapid identification of dairy mesophilic and thermophilic sporeforming bacteria using DNA high resolution melt analysis of variable 16S rDNA regions.  

PubMed

Due to their ubiquity in the environment and ability to survive heating processes, sporeforming bacteria are commonly found in foods. This can lead to product spoilage if spores are present in sufficient numbers and where storage conditions favour spore germination and growth. A rapid method to identify the major aerobic sporeforming groups in dairy products, including Bacillus licheniformis group, Bacillus subtilis group, Bacillus pumilus group, Bacillus megaterium, Bacillus cereus group, Geobacillus species and Anoxybacillus flavithermus was devised. This method involves real-time PCR and high resolution melt analysis (HRMA) of V3 (~70 bp) and V6 (~100 bp) variable regions in the 16S rDNA. Comparisons of HRMA curves from 194 isolates of the above listed sporeforming bacteria obtained from dairy products which were identified using partial 16S rDNA sequencing, allowed the establishment of criteria for differentiating them from each other and several non-sporeforming bacteria found in samples. A blinded validation trial on 28 bacterial isolates demonstrated complete accuracy in unambiguous identification of the 7 different aerobic sporeformers. The reliability of HRMA method was also verified using boiled extractions of crude DNA, thereby shortening the time needed for identification. The HRMA method described in this study provides a new and rapid approach to identify the dominant mesophilic and thermophilic aerobic sporeforming bacteria found in a wide variety of dairy products. PMID:23743474

Chauhan, Kanika; Dhakal, Rajat; Seale, R Brent; Deeth, Hilton C; Pillidge, Christopher J; Powell, Ian B; Craven, Heather; Turner, Mark S

2013-07-15

14

Diversity Surveys and Evolutionary Relationships of aoxB Genes in Aerobic Arsenite-Oxidizing Bacteria? †  

PubMed Central

A new primer set was designed to specifically amplify ca. 1,100 bp of aoxB genes encoding the As(III) oxidase catalytic subunit from taxonomically diverse aerobic As(III)-oxidizing bacteria. Comparative analysis of AoxB protein sequences showed variable conservation levels and highlighted the conservation of essential amino acids and structural motifs. AoxB phylogeny of pure strains showed well-discriminated taxonomic groups and was similar to 16S rRNA phylogeny. Alphaproteobacteria-, Betaproteobacteria-, and Gammaproteobacteria-related sequences were retrieved from environmental surveys, demonstrating their prevalence in mesophilic As-contaminated soils. Our study underlines the usefulness of the aoxB gene as a functional marker of aerobic As(III) oxidizers. PMID:18502920

Quéméneur, Marianne; Heinrich-Salmeron, Audrey; Muller, Daniel; Ličvremont, Didier; Jauzein, Michel; Bertin, Philippe N.; Garrido, Francis; Joulian, Catherine

2008-01-01

15

Simplified technique for identification of the aerobic spore-forming bacteria by phenotype.  

PubMed

The use of modern research approaches of genetics, biochemistry and molecular biology has led to progress in bacterial taxonomy. Systematic study of the aerobic spore-forming bacteria has resulted in the realignment of the genus Bacillus into several new genera. In the meantime, the identification process has become more difficult for the non-specialist in Bacillus taxonomy. This paper presents a key for the simplified phenotypic identification of the mesophilic, aerobic, spore-forming bacteria belonging to the genera Bacillus, Paenibacillus, Brevibacillus, Aneurinibacillus, Geobacillus and Virgibacillus. A total of 81 species were included and 115 morphological and physiological tests were analysed for their discriminative efficiency. This key is practical for rough but quick identification of aerobic spore-forming bacteria isolated from nature. Such preliminary identification will be helpful for the selection of reference strains and methods for more precise identification using the newest techniques. The reliability of the proposed identification key was tested on 100 cultures from the Ukrainian Collection of Microorganisms. The developed identification key is represented in interactive mode on a website (http://www/imv.kiev.ua/key/). PMID:11491334

Reva, O N; Sorokulova, I B; Smirnov, V V

2001-07-01

16

Conversion of cellulose to ethanol by mesophilic bacteria. Progress report and third year budget  

SciTech Connect

Much of our research has dealt with eight strains of obligately anaerobic bacteria that we isolated from various natural environments as described in last year's progress report. These eight strains (referred to as C strains) are strains of mesophilic, spore-forming, rod-shaped bacteria that ferment cellulose with production of ethanol. We determined quantitatively the fermentation products formed by C strains from cellulose and various other carbohydrates. In all cases ethanol was produced, as well as acetate, CO/sub 2/ and H/sub 2/. The C strains utilized, for ethanol production and growth, a variety of cellulosic substrates ranging from paper to alpha-cellulose. Enzymatic assays and growth studies showed that C strains possessed a celluloase system consisting of endoglucanase, exoglucanase, and cellobiase components. Studies indicated that growth substrates have a regulatory effect(s) on components of the cellulase system of the C strains. another experimental approach is aimed at cloning cellobiase, endoglucanase and exoglucanase genes from the C strains into a suitable vector plasmid and, eventually, at introducing the plasmid into cells of Zymomonas mobilis. The objective of this part of our research is to obtain a Z. mobilis strain capable of fermenting cellobiose and/or cellulose. Plasmids that contained DNA inserts were used to transform E. coli C600 recA. E. coli transformants that had acquired the cellobiase gene were obtained by this procedure. At present, we are attempting to introduce into Z. mobilis cells the vector plasmid purified from the E. coli transformants. In another series of experiments, we have used a new selective procedure to isolate four additional strains of mesophilic, obligately anaerobic, cellulolytic bacteria from natural environments.

Canale-Parola, E.

1982-11-24

17

Interaction of aerobic soil bacteria with plutonium(VI)  

Microsoft Academic Search

We studied the interaction of Pu(VI) with Pseudomonas stutzeri ATCC 17588 and Bacillus sphaericus ATCC 14577, representatives of the main aerobic groups of soil bacteria present in the upper soil layers. The accumulation studies have shown that these soil bacteria accumulate high amounts of Pu(VI). The sorption efficiency toward Pu(VI) decreased with increasing biomass concentration due to increased agglomeration of

Petra J. Panak; Heino Nitsche

2000-01-01

18

Characterization of aerobic spore-forming bacteria associated with industrial dairy processing environments and product spoilage.  

PubMed

Due to changes in the design of industrial food processing and increasing international trade, highly thermoresistant spore-forming bacteria are an emerging problem in food production. Minimally processed foods and products with extended shelf life, such as milk products, are at special risk for contamination and subsequent product damages, but information about origin and food quality related properties of highly heat-resistant spore-formers is still limited. Therefore, the aim of this study was to determine the biodiversity, heat resistance, and food quality and safety affecting characteristics of aerobic spore-formers in the dairy sector. Thus, a comprehensive panel of strains (n=467), which originated from dairy processing environments, raw materials and processed foods, was compiled. The set included isolates associated with recent food spoilage cases and product damages as well as isolates not linked to product spoilage. Identification of the isolates by means of Fourier-transform infrared spectroscopy and molecular methods revealed a large biodiversity of spore-formers, especially among the spoilage associated isolates. These could be assigned to 43 species, representing 11 genera, with Bacillus cereus s.l. and Bacillus licheniformis being predominant. A screening for isolates forming thermoresistant spores (TRS, surviving 100°C, 20 min) showed that about one third of the tested spore-formers was heat-resistant, with Bacillus subtilis and Geobacillus stearothermophilus being the prevalent species. Strains producing highly thermoresistant spores (HTRS, surviving 125°C, 30 min) were found among mesophilic as well as among thermophilic species. B. subtilis and Bacillus amyloliquefaciens were dominating the group of mesophilic HTRS, while Bacillus smithii and Geobacillus pallidus were dominating the group of thermophilic HTRS. Analysis of spoilage-related enzymes of the TRS isolates showed that mesophilic strains, belonging to the B. subtilis and B. cereus groups, were strongly proteolytic, whereas thermophilic strains displayed generally a low enzymatic activity and thus spoilage potential. Cytotoxicity was only detected in B. cereus, suggesting that the risk of food poisoning by aerobic, thermoresistant spore-formers outside of the B. cereus group is rather low. PMID:23973839

Lücking, Genia; Stoeckel, Marina; Atamer, Zeynep; Hinrichs, Jörg; Ehling-Schulz, Monika

2013-09-01

19

Biodegradation of Asphalt Cement-20 by Aerobic Bacteria  

PubMed Central

Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-degrading bacterium, Acinetobacter calcoaceticus NAV2, excretes an emulsifier which is capable of emulsifying the saturate and naphthene aromatic fractions of asphalt cement-20. This emulsifier is not denatured by phenol. PMID:16347928

Pendrys, John P.

1989-01-01

20

Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation.  

PubMed

The bacterial oxidation of nitrite to nitrate is a key process of the biogeochemical nitrogen cycle. Nitrite-oxidizing bacteria are considered a highly specialized functional group, which depends on the supply of nitrite from other microorganisms and whose distribution strictly correlates with nitrification in the environment and in wastewater treatment plants. On the basis of genomics, physiological experiments, and single-cell analyses, we show that Nitrospira moscoviensis, which represents a widely distributed lineage of nitrite-oxidizing bacteria, has the genetic inventory to utilize hydrogen (H2) as an alternative energy source for aerobic respiration and grows on H2 without nitrite. CO2 fixation occurred with H2 as the sole electron donor. Our results demonstrate a chemolithoautotrophic lifestyle of nitrite-oxidizing bacteria outside the nitrogen cycle, suggesting greater ecological flexibility than previously assumed. PMID:25170152

Koch, Hanna; Galushko, Alexander; Albertsen, Mads; Schintlmeister, Arno; Gruber-Dorninger, Christiane; Lücker, Sebastian; Pelletier, Eric; Le Paslier, Denis; Spieck, Eva; Richter, Andreas; Nielsen, Per H; Wagner, Michael; Daims, Holger

2014-08-29

21

Aerobic and microaerophilic bacteria isolated from Psoroptes cuniculi.  

PubMed

The bacterial flora of Psoroptes cuniculi removed from nine naturally infested rabbits was investigated. Mites were collected in sterile glass tubes; half of the mites were surface sterilised, the others were not. All mites were crushed using sterile glass pestles, placed in Buffered Peptone Broth, smeared on to several culture media, by glass rods, and incubated at 37 degrees C for 48 hours, aerobically and/or in 5% CO2. Representative colonies were removed and streaked on to several selective media. Different colour changes of the selective media used, macro and microscopic morphology, ability to grow aerobically, Gram staining, and several biochemical tests evaluated with API test strips, were used for bacterial identification. Staphylococcus aureus, Serratia marcescens and S. odorifera were the bacteria isolated from surface sterilised mites. PMID:12701376

Perrucci, S; Rossi, G

2002-12-01

22

Phylogenetic Diversity of Aerobic Saprotrophic Bacteria Isolated from the Daqing Oil Field  

Microsoft Academic Search

A diverse and active microbial community in the stratal waters of the Daqing oil field (China), which is exploited with the use of water-flooding, was found to contain aerobic chemoheterotrophic bacteria (including hydrocarbon-oxidizing ones) and anaerobic fermentative, sulfate-reducing, and methanogenic bacteria. The aerobic bacteria were most abundant in the near-bottom zones of injection wells. Twenty pure cultures of aerobic saprotrophic

T. N. Nazina; A. A. Grigor'yan; Yan-Fen Xue; D. Sh. Sokolova; E. V. Novikova; T. P. Tourova; A. B. Poltaraus; S. S. Belyaev; M. V. Ivanov

2002-01-01

23

Stability of the ‘L12 stalk’ in ribosomes from mesophilic and (hyper)thermophilic Archaea and Bacteria  

PubMed Central

The ribosomal stalk complex, consisting of one molecule of L10 and four or six molecules of L12, is attached to 23S rRNA via protein L10. This complex forms the so-called ‘L12 stalk’ on the 50S ribosomal subunit. Ribosomal protein L11 binds to the same region of 23S rRNA and is located at the base of the ‘L12 stalk’. The ‘L12 stalk’ plays a key role in the interaction of the ribosome with translation factors. In this study stalk complexes from mesophilic and (hyper)thermophilic species of the archaeal genus Methanococcus and from the Archaeon Sulfolobus solfataricus, as well as from the Bacteria Escherichia coli, Geobacillus stearothermophilus and Thermus thermophilus, were overproduced in E.coli and purified under non-denaturing conditions. Using filter-binding assays the affinities of the archaeal and bacterial complexes to their specific 23S rRNA target site were analyzed at different pH, ionic strength and temperature. Affinities of both archaeal and bacterial complexes for 23S rRNA vary by more than two orders of magnitude, correlating very well with the growth temperatures of the organisms. A cooperative effect of binding to 23S rRNA of protein L11 and the L10/L124 complex from mesophilic and thermophilic Archaea was shown to be temperature-dependent. PMID:17053098

Shcherbakov, D.; Dontsova, M.; Tribus, M.; Garber, M.; Piendl, W.

2006-01-01

24

Mesophilic and Psychrotrophic Bacteria from Meat and Their Spoilage Potential In Vitro and in Beef ?  

PubMed Central

Mesophilic and psychrotrophic populations from refrigerated meat were identified in this study, and the spoilage potential of microbial isolates in packaged beef was evaluated by analyzing the release of volatile organic compounds (VOC) by gas chromatography-mass spectrometry (GC/MS). Fifty mesophilic and twenty-nine psychrotrophic isolates were analyzed by random amplified polymorphic DNA-PCR, and representative strains were identified by 16S rRNA gene sequencing. Carnobacterium maltaromaticum and C. divergens were the species most frequently found in both mesophilic and psychrotrophic populations. Acinetobacter baumannii, Buttiauxella spp. and Serratia spp. were identified among the mesophilic isolates, while Pseudomonas spp. were commonly identified among the psychrotrophs. The isolates were further characterized for their growth at different temperatures and their proteolytic activity in vitro on meat proteins extracts at 7°C. Selected proteolytic strains of Serratia proteamaculans, Pseudomonas fragi, and C. maltaromaticum were used to examine their spoilage potential in situ. Single strains of these species and mixtures of these strains were used to contaminate beef chops that were packed and stored at 7°C. At time intervals up to 1 month, viable counts were determined, and VOC were identified by GC/MS. Generally, the VOC concentrations went to increase during the storage of the contaminated meats, and the profiles of the analyzed meat changed dramatically depending on the contaminating microbial species. About 100 volatiles were identified in the different contaminated samples. Among the detected volatiles, some specific molecules were identified only when the meat was contaminated by a specific microbial species. Compounds such as 2-ethyl-1-hexanol, 2-buten-1-ol, 2-hexyl-1-octanol, 2-nonanone, and 2-ethylhexanal were detectable only for C. maltaromaticum, which also produced the highest number of aldehydes, lactones, and sulfur compounds. The highest number of alcohols and ketons were detected in the headspace of meat samples contaminated by P. fragi, whereas the highest concentrations of some alcohols, such as 1-octen-3-ol, and some esters, such as isoamyl acetate, were produced by S. proteamaculans. In conclusion, different microbial species can contribute to meat spoilage with release of different volatile compounds that concur to the overall quality decrease of spoiling meat. PMID:19201980

Ercolini, Danilo; Russo, Federica; Nasi, Antonella; Ferranti, Pasquale; Villani, Francesco

2009-01-01

25

Mesophilic and psychrotrophic bacteria from meat and their spoilage potential in vitro and in beef.  

PubMed

Mesophilic and psychrotrophic populations from refrigerated meat were identified in this study, and the spoilage potential of microbial isolates in packaged beef was evaluated by analyzing the release of volatile organic compounds (VOC) by gas chromatography-mass spectrometry (GC/MS). Fifty mesophilic and twenty-nine psychrotrophic isolates were analyzed by random amplified polymorphic DNA-PCR, and representative strains were identified by 16S rRNA gene sequencing. Carnobacterium maltaromaticum and C. divergens were the species most frequently found in both mesophilic and psychrotrophic populations. Acinetobacter baumannii, Buttiauxella spp. and Serratia spp. were identified among the mesophilic isolates, while Pseudomonas spp. were commonly identified among the psychrotrophs. The isolates were further characterized for their growth at different temperatures and their proteolytic activity in vitro on meat proteins extracts at 7 degrees C. Selected proteolytic strains of Serratia proteamaculans, Pseudomonas fragi, and C. maltaromaticum were used to examine their spoilage potential in situ. Single strains of these species and mixtures of these strains were used to contaminate beef chops that were packed and stored at 7 degrees C. At time intervals up to 1 month, viable counts were determined, and VOC were identified by GC/MS. Generally, the VOC concentrations went to increase during the storage of the contaminated meats, and the profiles of the analyzed meat changed dramatically depending on the contaminating microbial species. About 100 volatiles were identified in the different contaminated samples. Among the detected volatiles, some specific molecules were identified only when the meat was contaminated by a specific microbial species. Compounds such as 2-ethyl-1-hexanol, 2-buten-1-ol, 2-hexyl-1-octanol, 2-nonanone, and 2-ethylhexanal were detectable only for C. maltaromaticum, which also produced the highest number of aldehydes, lactones, and sulfur compounds. The highest number of alcohols and ketons were detected in the headspace of meat samples contaminated by P. fragi, whereas the highest concentrations of some alcohols, such as 1-octen-3-ol, and some esters, such as isoamyl acetate, were produced by S. proteamaculans. In conclusion, different microbial species can contribute to meat spoilage with release of different volatile compounds that concur to the overall quality decrease of spoiling meat. PMID:19201980

Ercolini, Danilo; Russo, Federica; Nasi, Antonella; Ferranti, Pasquale; Villani, Francesco

2009-04-01

26

Methylophilus flavus sp. nov. and Methylophilus luteus sp. nov., aerobic, methylotrophic bacteria associated with plants.  

PubMed

Novel yellow, obligately methylotrophic and restricted facultatively methylotrophic bacteria, respectively designated strains Ship(T) and Mim(T), with the ribulose monophosphate pathway of C(1) assimilation are described. Cells were strictly aerobic, Gram-negative, asporogenous, non-motile rods that multiply by binary fission, were mesophilic and neutrophilic and synthesized indole-3-acetic acid and exopolysaccharide. The predominant cellular fatty acids were C(16?:?0) and C(16?:?1). The major ubiquinone was Q-8. The predominant phospholipids were phosphatidylethanolamine and phosphatidylglycerol; diphosphatidylglycerol was absent. The two strains lacked ?-ketoglutarate dehydrogenase and glutamate dehydrogenase. They assimilated ammonium via the glutamate cycle enzymes glutamine synthetase and glutamate synthase. The DNA G+C contents of strains Ship(T) and Mim(T) were 50.7 and 54.5 mol% (T(m)), respectively. The level of 16S rRNA gene sequence similarity between these strains was very high (99.8?%) but they shared a low level of DNA-DNA relatedness (44?%). Based on 16S rRNA gene sequence analysis and low levels of DNA-DNA relatedness with the type strains of recognized species of the genus Methylophilus (31-36?%), strains Ship(T) and Mim(T) are considered to represent novel species of the genus Methylophilus, for which the names Methylophilus flavus sp. nov. (type strain Ship(T) =DSM 23073(T) =VKM B-2547(T) =CCUG 58411(T)) and Methylophilus luteus sp. nov. (type strain Mim(T) =DSM 22949(T) =VKM B-2548(T) =CCUG 58412(T)) are proposed. PMID:20023062

Gogleva, Anna A; Kaparullina, Elena N; Doronina, Nina V; Trotsenko, Yuri A

2010-11-01

27

Occurrence of aerobic nitrogen fixing bacteria in wetland and dryland plants  

Microsoft Academic Search

We recently suggested that N2-fixing bacteria other than Azospirillum are present in greater abundance in the roots of wetland rice (2). Using a low concentration of tryptic soy agar, we isolated aerobic heterotrophic bacteria that required low levels of combined nitrogen for nitrogenase activity from wetland rice roots (1). In a liquid medium under batch culture conditions, the bacteria were

Wilfredo L. Barraquio; Iwao Watanabe

1981-01-01

28

Nitrososphaera viennensis gen. nov., sp. nov., an aerobic and mesophilic, ammonia-oxidizing archaeon from soil and a member of the archaeal phylum Thaumarchaeota  

PubMed Central

A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76T, was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6–0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76T had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76T had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76T is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85?% 16S rRNA gene sequence identity with the closest cultivated relative ‘Candidatus Nitrosopumilus maritimus’ SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81?% 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. ‘Korarchaeota’ and ‘Aigarchaeota’). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76T. The type strain of Nitrososphaera viennensis is strain EN76T (?=?DSM 26422T?=?JMC 19564T). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov. PMID:24907263

Stieglmeier, Michaela; Klingl, Andreas; Alves, Ricardo J. E.; Rittmann, Simon K.-M. R.; Melcher, Michael; Leisch, Nikolaus

2014-01-01

29

Combined mesophilic anaerobic and thermophilic aerobic digestion process for high-strength food wastewater to increase removal efficiency and reduce sludge discharge.  

PubMed

In this study, a process that combines the mesophilic anaerobic digestion (MAD) process with thermophilic aerobic digestion (TAD) for high-strength food wastewater (FWW) treatment was developed to examine the removal of organic matter and methane production. All effluent discharged from the MAD process was separated into solid and liquid portions. The liquid part was discarded and the sludge part was passed to the TAD process for further degradation. Then, the digested sludge from the TAD process was recycled back to the MAD unit to achieve low sludge discharge from the combined process. The reactor combination was operated in two phases: during Phase I, 40 d of total hydraulic retention time (HRT) was applied; during Phase II, 20 d was applied. HRT of the TAD process was fixed at 5 d. For a comparison, a control process (single-stage MAD) was operated with the same HRTs of the combined process. Our results indicated that the combined process showed over 90% total solids, volatile solids and chemical oxygen demand removal efficiencies. In addition, the combined process showed a significantly higher methane production rate than that of the control process. Consequently, the experimental data demonstrated that the combined MAD-TAD process was successfully employed for high-strength FWW treatment with highly efficient organic matter reduction and methane production. PMID:24759540

Jang, H M; Park, S K; Ha, J H; Park, J M

2014-01-01

30

Evaluation of the petrifilm aerobic count plate for enumeration of aerobic marine bacteria from seawater and Caulerpa lentillifera.  

PubMed

The enumeration and evaluation of the activity of marine bacteria are important in the food industry. However, detection of marine bacteria in seawater or seafood has not been easy. The Petrifilm aerobic count plate (ACP) is a ready-to-use alternative to the traditional enumeration media used for bacteria associated with food. The purpose of this study was to evaluate the usefulness of a simple detection and enumeration method utilizing the Petrifilm ACP for enumeration of aerobic marine bacteria from seawater and an edible seaweed, Caulerpa lentillifera. The efficiency of enumeration of total aerobic marine bacteria on Petrifilm ACP was compared with that using the spread plate method on marine agar with 80 seawater and 64 C. lentillifera samples. With sterile seawater as the diluent, a close correlation was observed between the method utilizing Petrifilm ACP and that utilizing the conventional marine agar (r=0.98 for seawater and 0.91 for C. lentillifera). The Petrifilm ACP method was simpler and less time-consuming than the conventional method. These results indicate that Petrifilm ACP is a suitable alternative to conventional marine agar for enumeration of marine microorganisms in seawater and C. lentillifera samples. PMID:20819367

Kudaka, Jun; Horii, Toru; Tamanaha, Koji; Itokazu, Kiyomasa; Nakamura, Masaji; Taira, Katsuya; Nidaira, Minoru; Okano, Sho; Kitahara, Akio

2010-08-01

31

Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide-  

E-print Network

Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide uranium [U(VI)] mediated by the intrinsic phosphatase acti- vities of naturally occurring bacteria such as uranium (U), technetium (Tc) and other toxic metals [e.g. cadmium (Cd), lead (Pb), chromium (Cr

Skolnick, Jeff

32

Studying the Life Cycle of Aerobic Endospore-forming Bacteria in Soil  

Microsoft Academic Search

\\u000a Members of the genus Bacillus are commonly isolated from soils, with members of the Bacillus cereus group being prevalent. Our knowledge of the ecology of B. cereus and other aerobic spore-forming bacteria in soil is far from complete. We have developed an in terra approach to study soil-associated aerobes, using filter-sterilized soil extracted soluble organic matter (SESOM). B. cereus is

Volker S. Brözel; Yun Luo; Sebastien Vilain

33

Developments in the Taxonomy of Aerobic, Endospore-forming Bacteria  

Microsoft Academic Search

\\u000a \\u000a Bacillus holds an important place in the history of bacteriology. With observations upon Bacillus subtilis and its spores Cohn discredited the theory of spontaneous generation, and with his demonstration of the life history of B. anthracis in 1876 Robert Koch proved the germ theory of disease and founded medical bacteriology. Later, Bacillus became defined as a genus of aerobic, endospore-forming

Niall A. Logan; Gillian Halket

34

Variable carbon isotope fractionation expressed by aerobic CH4-oxidizing bacteria  

E-print Network

Variable carbon isotope fractionation expressed by aerobic CH4-oxidizing bacteria Alexis S Engineering, Texas A&M University, College Station, TX 77843-3136, USA d Center for Isotope Geochemistry 2005; accepted in revised form 5 December 2005 Abstract Carbon isotope fractionation factors reported

Alvarez-Cohen, Lisa

35

Aerobic Anoxygenic Photosynthesis in Roseobacter Clade Bacteria from Diverse Marine Habitats  

Microsoft Academic Search

The marine Roseobacter clade comprises several genera of marine bacteria related to the uncultured SAR83 cluster, the second most abundant marine picoplankton lineage. Cultivated representatives of this clade are physiologically heterogeneous, and only some have the capability for aerobic anoxygenic photosynthesis, a process of potentially great ecological importance in the world's oceans. In an attempt to correlate phylogeny with ecology,

Martin Allgaier; Heike Uphoff; Andreas Felske; Irene Wagner-Dobler

2003-01-01

36

Time-dependent changes in viable numbers and activities of aerobic heterotrophic bacteria in subsurface samples  

Microsoft Academic Search

Vadose and saturated zone sediment cores from depths to 212 m were obtained from the U.S. Department of Energy's Hanford Site in south-central Washington by cable tool drilling, and volcanic ashfall tuff samples were obtained from tunnels 400 m beneath the surface of Rainier Mesa at DOE's Nevada Test Site (NTS) in southern Nevada. Numbers of viable aerobic heterotrophic bacteria

J. K. Fredrickson; S. W. Li; F. J. Brockman; D. L. Haldeman; P. S. Amy; D. L. Balkwill

1995-01-01

37

Molecular diversity of thermophilic cellulolytic and hemicellulolytic bacteria  

Microsoft Academic Search

Many thermophilic bacteria belong to groups with deep phylogenetic lineages and ancestral forms were established before the occurrence of eucaryotes that produced cellulose and hemicellulose. Thus they may have acquired their ?-glycanase genes from more recent mesophilic bacteria. Most research has focussed on extremely thermophilic eubacteria growing above 65°C under anaerobic conditions. Only recently have aerobic cellulolytic thermophiles been described

Peter L Bergquist; Moreland D Gibbs; Daniel D Morris; V. S. Junior Te'o; David J Saul; Hugh W Morgan

1999-01-01

38

Interaction between cyanobacteria and aerobic heterotrophic bacteria in the degradation of hydrocarbons  

Microsoft Academic Search

Four strains of aerobic heterotrophic bacteria were isolated on crude oil with the aim to test whether their presence and activity might support the growth of cyanobacteria in oil-polluted microbial mats and whether the cyanobacterial exudates might play a role in stimulating their degradative activities. The strains were phylogenetically related to known oil-degrading species from the genera Marinobacter, Pseudomonas and Sphingomonas. Three

Raeid M. M. Abed

2010-01-01

39

GC-MS structural characterization of fatty acids from marine aerobic anoxygenic phototrophic bacteria  

Microsoft Academic Search

The FA composition of 12 strains of marine aerobic anoxygenic phototrophic bacteria belonging to the genera Erythrobacter, Roseobacter, and Citromicrobium was investigated. GC-MS analyses of different types of derivatives were performed to determine the structures of the main\\u000a FA present in these organisms. All the analyzed strains contained the relatively rare 11-methyloctadec-12-enoic acid, and\\u000a three contained 12-methyl-octadec-11-enoic acid, which has

J.-F. Rontani; S. Christodoulou; M. Koblizek

2005-01-01

40

Isolation and characterization of aerobic thermophilic bacteria from the savusavu hot springs in fiji.  

PubMed

The relative isolation and unique physical properties of the Savusavu Hot Springs in Fiji may yield unique thermophiles. This study was conducted to determine the presence of aerobic thermophilic bacteria in these hot springs. A total of 104 thermophilic bacterial isolates were characterized and using Thermus and Bacillus strains as controls, 58% of the isolates were identified as Anoxybacillus flavithermus, 19% as Geobacillus stearothermophilus/Bacillus licheniformis, 10% as Thermus sp. TG153 and 10% as Thermus sp. TG206. Four isolates were unique in their molecular patterns suggesting there may be novel bacteria in the Savusavu hot springs. PMID:21558730

Narayan, Vinay V; Hatha, Mohamed A; Morgan, Hugh W; Rao, Dhana

2008-01-01

41

Murata [eds.], Aerobic photosynthetic bacteria. Japan Scientific IMHOFF, J. F. 1992. Taxonomy, phyologeny, and general ecology of  

E-print Network

Ā­2495. , C. L. VAN DOVER, R. A. NIEDERMAN, AND P. G. FAL- KOWSKI. 2000. Bacterial photosynthesis in surface. Distribution of aerobic bacteria which contain bacteriochlorophyll a. Appl. Environ. Microbiol. 38: 43

Vincent, Warwick F.

42

Fluorescence studies on the stability, flexibility and substrate-induced conformational changes of acetate kinases from psychrophilic and mesophilic bacteria.  

PubMed

The acetate kinase from the Antarctic psychrophilic Shewanella sp. AS-11 (SAK) has a significantly higher catalytic efficiency at low temperatures when compared with that from mesophilic Escherichia coli K-12 (EAK). To examine the stability and conformational flexibility of SAK and EAK, steady state intrinsic fluorescence studies were performed. EAK contains only one Trp at a position 46, while SAK contains two Trps at positions 46 and 388. From the fluorescence emission spectra, quenching with acrylamide, Cs(+) and I(-) at different temperatures and denaturation with guanidine-HCl, it was revealed that the SAK bears more flexible and unstable structure than that of EAK. Substrate-induced conformational changes reflect that SAK reached transition state through more conformational changes than EAK. In combination of our thermodynamic studies on the enzymatic reaction and present research findings, it can be concluded that these structural features of SAK may contribute to its high catalytic efficiency at low temperatures. PMID:22481532

Tang, Md Abul Kashem; Motoshima, Hiroyuki; Watanabe, Keiichi

2012-04-01

43

Biodegradation of nonlignocellulosic substances I: system for complete decomposition of garbage using sawdust and aerobic soil bacteria  

Microsoft Academic Search

A system for effective garbage decomposition using sawdust and aerobic soil bacteria was examined. The machinery used in this\\u000a process, the garbage automatic decomposer-extinguisher (GADS), is composed of a container with an automatic mechanical mixer\\u000a and a drain for liquid formed by the decomposition of garbage. The aerobic soil bacteria, cultivated in sawdust, degrades\\u000a garbage within the container. The GADE

Minoru Terazawa; Sakae Horisawa; Yutaka Tamai; Kenzo Yamashita

1999-01-01

44

[Aniline removal by aerobic granules and high-efficiency aniline-degrading bacteria].  

PubMed

Aerobic granules were successfully cultivated with aniline as the sole source of carbon and nitrogen. This system could effectively degrade aniline as high as 6 000 mg/L. Two aniline-degrading strains which were named as adx1 and adx3, were isolated and purified from the aerobic granular sludge. The degradation characteristics of these two bacteria were different. The strain adxl possessed a relatively higher degradation rate of aniline, while the strain adx3 could stand up to a higher concentration of aniline than the strain adx1. The degrading process of these two strains followed the Haldane kinetic model. The maximum aniline biodegradation rates of adx1 and adx3 were up to 0.924 g/(g x h) and 0.645 g/(g x h), respectively. The maximum specific growth rates were as high as 0.487 g/(g x h) and 0.440 g/(g x h), respectively. Identification by 16S rDNA gene sequence analysis showed that adx1 and adx3 were Pseudomonas sp. and Achromobacter sp., which was consistent with the identification by the bands 1 and 4 in the PCR-DGGE profile of the aerobic aniline-degrading granules. Therefore, it could be proposed that the strains adx1 and adx3 were one of the main functional microorganisms inhabited in the aerobic granules. PMID:20063750

Xiang, Zheng-Xin; Zhang, Li-Li; Chen, Jian-Meng

2009-11-01

45

Influence of bovine lactoferrin on the growth of selected probiotic bacteria under aerobic conditions.  

PubMed

Bovine lactoferrin (bLf) is a natural glycoprotein, and it shows broad-spectrum antimicrobial activity. However, reports on the influences of bLf on probiotic bacteria have been mixed. We examined the effects of apo-bLf (between 0.25 and 128 mg/mL) on both aerobic and anaerobic cultures of probiotics. We found that bLf had similar effects on the growth of probiotics under aerobic or anaerobic conditions, and that it actively and significantly (at concentrations of >0.25 mg/mL) retarded the growth rate of Bifidobacterium bifidum (ATCC 29521), B. longum (ATCC 15707), B. lactis (BCRC 17394), B. infantis (ATCC 15697), Lactobacillus reuteri (ATCC 23272), L. rhamnosus (ATCC 53103), and L. coryniformis (ATCC 25602) in a dose-dependent manner. Otherwise, minimal inhibitory concentrations (MICs) were 128 or >128 mg/mL against B. bifidum, B. longum, B. lactis, L. reuteri, and L. rhamnosus (ATCC 53103). With regard to MICs, bLf showed at least four-fold lower inhibitory effect on probiotics than on pathogens. Intriguingly, bLf (>0.25 mg/mL) significantly enhanced the growth of Rhamnosus (ATCC 7469) and L. acidophilus (BCRC 14065) by approximately 40-200 %, during their late periods of growth. Supernatants produced from aerobic but not anaerobic cultures of L. acidophilus reduced the growth of Escherichia coli by about 20 %. Thus, bLf displayed a dose-dependent inhibitory effect on the growth of most probiotic strains under either aerobic or anaerobic conditions. An antibacterial supernatant prepared from the aerobic cultures may have significant practical use. PMID:24916115

Chen, Po-Wen; Ku, Yu-We; Chu, Fang-Yi

2014-10-01

46

The effect of bacteria, enzymes and inulin on fermentation and aerobic stability of corn silage  

PubMed Central

Background and Objectives Ensiling is a conservation method for forage crops. It is based on the fact that anaerobe lactic acid bacteria (LAB) convert watersoluble carbohydrates into organic acids. Therefore, pH decreases and the forage is preserved. The aim of this study was to isolate special kinds of lactic acid bacteria from silage and to study the effect of bacteria, inulin and enzymes as silage additives on the fermentation and aerobic stability of the silage. Materials and Methods The heterofermentative LAB were isolated from corn silages in Broujerd, Iran and biochemically characterized. Acid tolerance was studied by exposure to acidic PBS and growth in bile salt was measured by the spectrophotometric method. Results The results of molecular analysis using 16SrDNA sequences showed that the isolates belonged to Lactobacillus and Enterococcus genera. To enhance stability in acidic environment and against bile salts, microencapsulation with Alginate and Chitosan was used. The Lactobacillus plantarum strains were used as control. The inoculants (1 × 107 cfu/g) alone or in combination with inulin or in combination with enzymes were added to chopped forages and ensiled in 1.5-L anaerobic jars. Conclusion Combination of the isolates Lactobacillus and Enterococcus with inulin and enzymes can improve the aerobic stability of corn silage. PMID:23205249

Peymanfar, S; Kermanshahi, RK

2012-01-01

47

Dynamic of functional microbial groups during mesophilic composting of agro-industrial wastes and free-living (N2)-fixing bacteria application.  

PubMed

Although several reports are available concerning the composition and dynamics of the microflora during the composting of municipal solid wastes, little is known about the microbial diversity during the composting of agro-industrial refuse. For this reason, the first parts of this study included the quantification of microbial generic groups and of the main functional groups of C and N cycle during composting of agro-industrial refuse. After a generalized decrease observed during the initial phases, a new bacterial growth was observed in the final phase of the process. Ammonifiers and (N2)-fixing aerobic groups predominated outside of the piles whereas, nitrate-reducing group increased inside the piles during the first 23days of composting. Ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), showed an opposite trend of growth since ammonia oxidation decreased with the increase of the nitrite oxidation activity. Pectinolytics, amylolytics and aerobic cellulolytic were present in greater quantities and showed an upward trend in both the internal and external part of the heaps. Several free-living (N2)-fixing bacteria were molecularly identify as belonging especially to uncommon genera of nitrogen-fixing bacteria as Stenotrophomonas, Xanthomonas, Pseudomonas, Klebsiella, Alcaligenes, Achromobacter and Caulobacter. They were investigated for their ability to fix atmospheric nitrogen to employ as improvers of quality of compost. Some strains of Azotobacter chrococcum and Azotobacter salinestris were also tested. When different diazotrophic bacterial species were added in compost, the increase of total N ranged from 16% to 27% depending on the selected microbial strain being used. Such microorganisms may be used alone or in mixtures to provide an allocation of plant growth promoting rhizobacteria in soil. PMID:23647951

Pepe, Olimpia; Ventorino, Valeria; Blaiotta, Giuseppe

2013-07-01

48

Quantification of syntrophic fatty acid-{beta}-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization  

SciTech Connect

Small-subunit rRNA sequences were obtained for two saturated fatty acid-{beta}-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S.wolfei LYB was closely related to S.wolfei subsp. solfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA of different groups within the family Syntrophomonadaceae, which contains all currently known saturated fatty acid-{beta}-oxidizing syntrophic bacteria, were developed and characterized. The probes were designed to be specific at the family, genus, and species levels and were characterized by temperature-of-dissociation and specificity studies. To demonstrate the usefulness of the probes for the detection and quantification of saturated fatty acid-{beta}-oxidizing syntrophic bacteria in methanogenic environments, the microbial community structure of a sample from a full-scale biogas plant was determined. Hybridization results with probes for syntrophic bacteria and methanogens were compared to specific methanogenic activities and microbial numbers determined with most-probable-number estimates. Most of the methanogenic rRNA was comprised of Methanomicrobiales rRNA, suggesting that members of this order served as the main hydrogen-utilizing microorganisms. Between 0.2 and 1% of the rRNA was attributed to the Syntrophomonadaceae, or which the majority was accounted for by the genus Syntrophomonas.

Hansen, K.H.; Ahring, B.K.; Raskin, L.

1999-11-01

49

Diversity and function of aerobic culturable bacteria in the intestine of the sea cucumber Holothuria leucospilota.  

PubMed

Sea cucumbers play an important role in nutrient cycling of marine ecosystems by consuming sediments and moving sand, thus occupying a similar niche to earthworms in terrestrial ecosystems. However, our understanding of microbial diversity and functions associated with sea cucumbers is meager. Here, we isolated 141 bacterial strains under aerobic conditions using various media from the intestine of Holothuria leucospilota, a common sea cucumber in Japanese warm waters. By partial 16S rRNA gene sequences of the isolates, the isolates were tentatively affiliated with 55 described species. Among them, 23 species were common between 2 individuals of H. leucospilota. High diversity was observed in the genera Bacillus and Vibrio, which are often found in marine sediments, marine animals and other various environments. Most isolates showed various polysaccharide degradation activities and were able to grow under or were tolerant of anaerobic condition. We suggest that these aerobically isolated bacteria can play a role in digestion of detritus in aerobic and/or anaerobic regions of the intestine. PMID:23337580

Zhang, Xiaochi; Nakahara, Tomomi; Miyazaki, Masayuki; Nogi, Yuichi; Taniyama, Shigeto; Arakawa, Osamu; Inoue, Tetsushi; Kudo, Toshiaki

2012-01-01

50

Quantification of syntrophic fatty acid-Ī²-oxidizing bacteria in a mesophilic biogas reactor by oligonucleotide probe hybridization  

Microsoft Academic Search

Small-subunit rRNA sequences were obtained for two saturated fatty acid-Ī²-oxidizing syntrophic bacteria, Syntrophomonas sapovorans and Syntrophomonas wolfei LYB, and sequence analysis confirmed their classification as members of the family Syntrophomonadaceae. S.wolfei LYB was closely related to S.wolfei subsp. solfei, but S. sapovorans did not cluster with the other members of the genus Syntrophomonas. Five oligonucleotide probes targeting the small-subunit rRNA

KAARE H. HANSEN; BIRGITTE K. AHRING; LUTGARDE RASKIN

1999-01-01

51

Comparative antimicrobial susceptibility of aerobic and facultative bacteria from community-acquired bacteremia to ertapenem in Taiwan  

Microsoft Academic Search

BACKGROUND: Ertapenem is a once-a-day carbapenem and has excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The susceptibility of isolates of community-acquired bacteremia to ertapenem has not been reported yet. The present study assesses the in vitro activity of ertapenem against aerobic and facultative bacterial pathogens isolated from patients with community-acquired bacteremia by determining and comparing

Sai-Cheong Lee; Shie-Shian Huang; Chao-Wei Lee; Ning Lee; Wen-Bin Shieh; LK Siu

2007-01-01

52

Diverse Arrangement of Photosynthetic Gene Clusters in Aerobic Anoxygenic Phototrophic Bacteria  

PubMed Central

Background Aerobic anoxygenic photototrophic (AAP) bacteria represent an important group of marine microorganisms inhabiting the euphotic zone of the ocean. They harvest light using bacteriochlorophyll (BChl) a and are thought to be important players in carbon cycling in the ocean. Methodology/Principal Findings Aerobic anoxygenic phototrophic (AAP) bacteria represent an important part of marine microbial communities. Their photosynthetic apparatus is encoded by a number of genes organized in a so-called photosynthetic gene cluster (PGC). In this study, the organization of PGCs was analyzed in ten AAP species belonging to the orders Rhodobacterales, Sphingomonadales and the NOR5/OM60 clade. Sphingomonadales contained comparatively smaller PGCs with an approximately size of 39 kb whereas the average size of PGCs in Rhodobacterales and NOR5/OM60 clade was about 45 kb. The distribution of four arrangements, based on the permutation and combination of the two conserved regions bchFNBHLM-LhaA-puhABC and crtF-bchCXYZ, does not correspond to the phylogenetic affiliation of individual AAP bacterial species. While PGCs of all analyzed species contained the same set of genes for bacteriochlorophyll synthesis and assembly of photosynthetic centers, they differed largely in the carotenoid biosynthetic genes. Spheroidenone, spirilloxanthin, and zeaxanthin biosynthetic pathways were found in each clade respectively. All of the carotenoid biosynthetic genes were found in the PGCs of Rhodobacterales, however Sphingomonadales and NOR5/OM60 strains contained some of the carotenoid biosynthetic pathway genes outside of the PGC. Conclusions/Significance Our investigations shed light on the evolution and functional implications in PGCs of marine aerobic anoxygenic phototrophs, and support the notion that AAP are a heterogenous physiological group phylogenetically scattered among Proteobacteria. PMID:21949847

Zheng, Qiang; Zhang, Rui; Koblķžek, Michal; Boldareva, Ekaterina N.; Yurkov, Vladimir; Yan, Shi; Jiao, Nianzhi

2011-01-01

53

Increased salinity improves the thermotolerance of mesophilic nitrification.  

PubMed

Nitrification is a well-studied and established process to treat ammonia in wastewater. Although thermophilic nitrification could avoid cooling costs for the treatment of warm wastewaters, applications above 40 °C remain a significant challenge. This study tested the effect of salinity on the thermotolerance of mesophilic nitrifying sludge (34 °C). In batch tests, 5 g NaCl L(-1) increased the activity of aerobic ammonia-oxidizing bacteria (AerAOB) by 20-21 % at 40 and 45 °C. For nitrite-oxidizing bacteria (NOB), the activity remained unaltered at 40 °C, yet decreased by 83 % at 45 °C. In a subsequent long-term continuous reactor test, temperature was increased from 34 to 40, 42.5, 45, 47.5 and 50 °C. The AerAOB activity showed 65 and 37 % higher immediate resilience in the salt reactor (7.5 g NaCl L(-1)) for the first two temperature transitions and lost activity from 45 °C onwards. NOB activity, in contrast to the batch tests, was 37 and 21 % more resilient in the salt reactor for the first two transitions, while no difference was observed for the third temperature transition. The control reactor lost NOB activity at 47.5 °C, while the salt reactor only lost activity at 50 °C. Overall, this study demonstrates salt amendment as a tool for a more efficient temperature transition for mesophilic sludge (34 °C) and eventually higher nitrification temperatures. PMID:24526362

Courtens, Emilie N P; Boon, Nico; De Schryver, Peter; Vlaeminck, Siegfried E

2014-05-01

54

New aerobic ammonium-dependent obligately oxalotrophic bacteria: description of Ammoniphilus oxalaticus gen. nov., sp. nov. and Ammoniphilus oxalivorans gen. nov., sp. nov.  

PubMed

The genus Ammoniphilus is proposed for aerobic endospore-forming Gram-variable rod-shaped bacteria, which are ammonium-dependent, obligately oxalotrophic and haloalkalitolerant, oxidase- and catalase-positive, mesophilic and motile by peritrichous flagella. Cell wall contained two electron-dense layers. The external layer consists of a chain of electron-dense granules morphologically resembling the cellulosomes of Clostridium thermocellum. Two species are described, Ammoniphilus oxalaticus gen. nov., sp. nov. and Ammoniphilus oxalivorans gen. nov., sp. nov. The type strains of these species are strains RAOx-1 (= DSM 11538) and RAOx-FS (= DSM 11537), respectively. Ammoniphilus strains were isolated from the rhizosphere of sorrel (Rumex acetosa) and from decaying wood. The strains require a high concentration of ammonium ions and use oxalate as the sole organic source of carbon and energy for growth; no growth factors were required. Growth occurred at pH 6.8-9.5. The optimum temperature and pH for growth were 28-30 degrees C and 8.0-8.5. All strains grew in a saturated solution of ammonium oxalate, and tolerated 3% NaCl. Whole-cell hydrolysates contain meso-diaminopimelic acid and glucose. The menaquinone of the strains was MK 7, and the major cellular fatty acids were 12-methyl tetradecanoic, cis-hexadec-9-enoic and hexadecanoic acids. The G + C content of the DNA was 45-46 mol% for A. oxalaticus and 42 mol% for A. oxalivorans. The almost complete 16S rDNA sequence of three strains of the two species of Ammoniphilus shows that the genus falls into the radiation of the Clostridium-Bacillus subphylum of Gram-positive bacteria. The closest phylogenetic neighbour of Ammoniphilus is Oxalophagus oxalicus. The DNA-DNA hybridization value between strains RAOx-1 and RAOx-FS was 39.7%. PMID:9542085

Zaitsev, G M; Tsitko, I V; Rainey, F A; Trotsenko, Y A; Uotila, J S; Stackebrandt, E; Salkinoja-Salonen, M S

1998-01-01

55

Characterisation of aerobically grown non-spore-forming bacteria from paper mill pulps containing recycled fibres.  

PubMed

A total of 179 non-spore-forming bacteria aerobically growing on Nutrient Agar, Plate Count Agar or in specific enrichment conditions for salmonella, campylobacteria, listeria, yersinia or staphylococci, were isolated from 16 untreated paper mill pulps. After phenotypical screening the isolates were characterised by automated ribotyping and partial sequencing of the 16S rRNA gene. They could be divided into seven taxonomical classes representing 63 taxa (species): actinobacteria (11 species), bacilli (7), flavobacteria (3) alphaproteobacteria (10), betaproteobacteria (5), gammaproteobacteria (25) and sphingobacteria (2). Most of the gammaproteobacteria were enterobacteria, mainly species of the genera Enterobacter (7 species, 7 samples/3 mills) and Klebsiella (5 species, 6 samples/3 mills). Other commonly occurring bacteria were most closely related to Microbacterium barkeri (7 samples/3 mills), Cloacibacterium normanense (6 samples/2 mills), Pseudoxanthomonas taiwanensis (5 samples/2 mills) and Sphingobacterium composti (5 samples/1 mill). Sporadic isolates of Listeria innocua, L. monocytogenes, Enterococcus casseliflavus and Staphylococcus warneri were detected, from which only L. monocytogenes is considered to be a food pathogen. No isolates of the genera Campylobacter, Salmonella or Yersinia were detected. The detected bacteria may be harmful in process control, but the load of food pathogens with recycled fibres to paper machines is insignificant. Faecal contamination of the pulp samples was not indicated. PMID:18820960

Suihko, Maija-Liisa; Skyttä, Eija

2009-01-01

56

Aerobic and anaerobic de-epoxydation of mycotoxin deoxynivalenol by bacteria originating from agricultural soil.  

PubMed

One hundred and fifty soil samples collected from different crop fields in southern Ontario, Canada were screened to obtain microorganisms capable of transforming deoxynivalenol (DON) to de-epoxy DON (dE-DON). Microbial DON to dE-DON transformation (i.e. de-epoxydation) was monitored by using liquid chromatography-ultraviolet-mass spectrometry (LC-UV-MS). The effects of growth substrates, temperature, pH, incubation time and aerobic versus anaerobic conditions on the ability of the microbes to de-epoxydize DON were evaluated. A mixed microbial culture from one composite soil sample showed 100% DON to dE-DON biotransformation in mineral salts broth (MSB) after 144 h of incubation. Treatments of the culture with selective antibiotics followed an elevated temperature (50°C) for 1.5 h considerably reduced the microbial diversity. Partial 16S-rRNA gene sequence analysis of the bacteria in the enriched culture indicated the presence of at least six bacterial genera, namely Serratia, Clostridium, Citrobacter, Enterococcus, Stenotrophomonas and Streptomyces. The enriched culture completely de-epoxydized DON after 60 h of incubation. Bacterial de-epoxydation of DON occurred at pH 6.0-7.5, and a wide array of temperatures (12-40°C). The culture showed rapid de-epoxydation activity under aerobic conditions compared to anaerobic conditions. This is the first report on microbial DON to dE-DON transformation under aerobic conditions and moderate temperatures. The culture could be used to detoxify DON contaminated feed and might be a potential source for gene(s) for DON de-epoxydation. PMID:22806774

Islam, Rafiqul; Zhou, Ting; Young, J Christopher; Goodwin, Paul H; Pauls, K Peter

2012-01-01

57

Dynamic and distribution of ammonia-oxidizing bacteria communities during sludge granulation in an anaerobic–aerobic sequencing batch reactor  

Microsoft Academic Search

The structure dynamic of ammonia-oxidizing bacteria (AOB) community and the distribution of AOB and nitrite-oxidizing bacteria (NOB) in granular sludge from an anaerobic–aerobic sequencing batch reactor (SBR) were investigated. A combination of process studies, molecular biotechniques and microscale techniques were employed to identify and characterize these organisms. The AOB community structure in granules was substantially different from that of the

Zhang Bin; Chen Zhe; Qiu Zhigang; Jin Min; Chen Zhiqiang; Chen Zhaoli; Li Junwen; Wang Xuan; Wang Jingfeng

2011-01-01

58

Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.  

PubMed

In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid. PMID:25416587

Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

2014-11-22

59

Analyses of Spatial Distributions of Sulfate-Reducing Bacteria and Their Activity in Aerobic Wastewater Biofilms  

PubMed Central

The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O2, H2S, NO2?, NO3?, NH4+, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells (approximately 109 to 1010 cells per cm3 of biofilm) were evenly distributed throughout the biofilm, even in the oxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations (approximately 108 to 109 cells per cm3). The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 ?m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 ?m), which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate. PMID:10543829

Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

1999-01-01

60

Isolation of optically targeted single bacteria by application of fluidic force microscopy to aerobic anoxygenic phototrophs from the phyllosphere.  

PubMed

In their natural environment, bacteria often behave differently than they do under laboratory conditions. To gain insight into the physiology of bacteria in situ, dedicated approaches are required to monitor their adaptations and specific behaviors under environmental conditions. Optical microscopy is crucial for the observation of fundamental characteristics of bacteria, such as cell shape, size, and marker gene expression. Here, fluidic force microscopy (FluidFM) was exploited to isolate optically selected bacteria for subsequent identification and characterization. In this study, bacteriochlorophyll-producing bacteria, which can be visualized due to their characteristic fluorescence in the infrared range, were isolated from leaf washes. Bacterial communities from the phyllosphere were investigated because they harbor genes indicative of aerobic anoxygenic photosynthesis. Our data show that different species of Methylobacterium express their photosystem in planta, and they show a distinct pattern of bacteriochlorophyll production under laboratory conditions that is dependent on supplied carbon sources. PMID:23770907

Stiefel, Philipp; Zambelli, Tomaso; Vorholt, Julia A

2013-08-01

61

Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria  

NASA Astrophysics Data System (ADS)

Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and food production for human thus rely on local Martian resources. A tree growing subsystem will also give an interesting feature to Martian agriculture. In addition to producing excess oxygen, trees’ rigid body will provide structural material, which can be used for habitat construction. The combination of hyper-thermophilic aerobic composting, plant cultivation, and tree growing with utilizing in-situ natural local resources available on Mars can provide important elements which can enable space agriculture on Mars.

Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

62

Production of Wax Esters during Aerobic Growth of Marine Bacteria on Isoprenoid Compounds  

PubMed Central

This paper describes the production of isoprenoid wax esters during the aerobic degradation of 6,10,14-trimethylpentadecan-2-one and phytol by four bacteria (Acinetobacter sp. strain PHY9, Pseudomonas nautica [IP85/617], Marinobacter sp. strain CAB [DSMZ 11874], and Marinobacter hydrocarbonoclasticus [ATCC 49840]) isolated from the marine environment. Different pathways are proposed to explain the formation of these compounds. In the case of 6,10,14-trimethylpentadecan-2-one, these esters result from the condensation of some acidic and alcoholic metabolites produced during the biodegradation, while phytol constitutes the alcohol moiety of most of the esters produced during growth on this isoprenoid alcohol. The amount of these esters formed increased considerably in N-limited cultures, in which the ammonium concentration corresponds to conditions often found in marine sediments. This suggests that the bacterial formation of isoprenoid wax esters might be favored in such environments. Although conflicting evidence exists regarding the stability of these esters in sediments, it seems likely that, under some conditions, bacterial esterification can enhance the preservation potential of labile compounds such as phytol. PMID:9872783

Rontani, Jean-Francois; Bonin, Patricia C.; Volkman, John K.

1999-01-01

63

In Vitro Activities of Membrane-Active Peptides against Gram-Positive and Gram-Negative Aerobic Bacteria  

Microsoft Academic Search

Four peptides, cecropin P1, magainin II, indolicidin, and ranalexin, were evaluated against 202 clinical isolates of gram-positive and gram-negative aerobic bacteria by a microbroth dilution method. The gram- negative isolates were more susceptible to cecropin P1. Ranalexin was the most active compound against the gram-positive strains. The bactericidal activity of each peptide was equivalent to, or 1 dilution above, the

A. GIACOMETTI; O. CIRIONI; G. GREGANTI; M. QUARTA; G. SCALISE

1998-01-01

64

Induction of bphA, Encoding Biphenyl Dioxygenase, in Two Polychlorinated Biphenyl-Degrading Bacteria, Psychrotolerant Pseudomonas Strain Cam1 and Mesophilic Burkholderia Strain LB400  

Microsoft Academic Search

We investigated induction of biphenyl dioxygenase in the psychrotolerant polychlorinated biphenyl (PCB) degrader Pseudomonas strain Cam-1 and in the mesophilic PCB degrader Burkholderia strain LB400. Using a counterselectable gene replacement vector, we inserted a lacZ-Gmr fusion cassette between chromosomal genes encoding the large subunit (bphA) and small subunit (bphE) of biphenyl dioxygenase in Cam-1 and LB400, generating Cam-10 and LB400-1,

EMMA R. MASTER; WILLIAM W. MOHN

2001-01-01

65

Culturing Aerobic and Anaerobic Bacteria and Mammalian Cells with a Microfluidic Differential Oxygenator  

E-print Network

In this manuscript, we report on the culture of anaerobic and aerobic species within a disposable multilayer polydimethylsiloxane (PDMS) microfluidic device with an integrated differential oxygenator. A gas-filled microchannel ...

Lam, Raymond H. W.

66

Variable carbon isotope fractionation expressed by aerobic CH 4-oxidizing bacteria  

NASA Astrophysics Data System (ADS)

Carbon isotope fractionation factors reported for aerobic bacterial oxidation of CH 4(?) range from 1.003 to 1.039. In a series of experiments designed to monitor changes in the carbon isotopic fractionation of CH 4 by Type I and Type II methanotrophic bacteria, we found that the magnitude of fractionation was largely due to the first oxidation step catalyzed by methane monooxygenase (MMO). The most important factor that modulates the (?) is the fraction of the total CH 4 oxidized per unit time, which strongly correlates to the cell density of the growth cultures under constant flow conditions. At cell densities of less than 0.1 g/L, fractionation factors greater than 1.03 were observed, whereas at cell densities greater than 0.5 g/L the fractionation factors decreased to as low as 1.002. At low cell densities, low concentrations of MMO limit the amount of CH 4 oxidized, while at higher cell densities, the overall rates of CH 4 oxidation increase sufficiently that diffusion of CH 4 from the gaseous to dissolved state and into the cells is likely the rate-determining step. Thus, the residual CH 4 is more fractionated at low cell densities, when only a small fraction of the total CH 4 has been oxidized, than at high cell densities, when up to 40% of the influent CH 4 has been utilized. Therefore, since Rayleigh distillation behavior is not observed, ? 13C values of the residual CH 4 cannot be used to infer the amount oxidized in either laboratory or field-studies. The measured (?) was the same for both Type I and Type II methanotrophs expressing particulate or soluble MMO. However, large differences in the ? 13C values of biomass produced by the two types of methanotrophs were observed. Methylosinus trichosporium OB3b (Type II) produced biomass with ? 13C values about 15‰ higher than the dissimilated CO 2, whereas Methylomonas methanica (Type I) produced biomass with ? 13C values only about 6‰ higher than the CO 2. These effects were independent of the magnitude of the initial carbon isotope fractionation caused by MMO and were relatively constant despite changing ratios of assimilatory to dissimilatory carbon transformation by the organisms. This suggests that the difference in biomass carbon isotopes is primarily due to differences in the fractionation effect at the formaldehyde branch point in the metabolic pathway, rather than assimilation of CO 2 by Type II methanotrophs.

Templeton, Alexis S.; Chu, Kung-Hui; Alvarez-Cohen, Lisa; Conrad, Mark E.

2006-04-01

67

Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice  

PubMed Central

A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB) and organic acids (oxalic & malic) on phosphate (P) solubilization from phosphate rock (PR) and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30?mM), and PSB strain (Bacillus sp.) were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20?mM along with PSB16 significantly increased soluble soil P (28.39?mg kg?1), plant P uptake (0.78?P pot?1), and plant biomass (33.26?mg). Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10?cfu g?1) compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH. PMID:24288473

Jusop, Shamshuddin; Naher, Umme Aminun; Othman, Radziah; Razi, Mohd Ismail

2013-01-01

68

Evidence for propagation of aerobic bacteria in particles suspended in gaseous atmospheres. [Terrestrial microorganism contamination of Jupiter atmosphere  

NASA Technical Reports Server (NTRS)

One factor involved in the possibility that airborne microbes might contaminate the Jovian atmosphere is whether microbes have the capacity to propagate in air. Prior to these studies, the evidence was that the airborne state was lethal to microbes. An aerosol of aerobic bacteria was mixed with another containing C-14-glucose, and the presence of C-14-CO2 was subsequently detected, which indicates that the airborne cells were metabolically active. In the same type of experiment, it was shown that thymidine was incorporated into the acid-insoluble fraction of samples, indicating the formation of DNA. It was also shown, both by an increase in the numbers of viable cells and a parallel increase in particle numbers, that at least two new generations of cells could occur. Evidence for propagation of anaerobic bacteria has so far been negative.

Dimmick, R. L.; Chatigny, M. A.; Wolochow, H.; Straat, P.

1977-01-01

69

Phylogenetic analysis of nitric oxide reductase gene homologues from aerobic ammonia-oxidizing bacteria  

E-print Network

-oxidizing bacteria Karen L. Casciotti *,1 , Bess B. Ward Department of Geosciences, Princeton University, Princeton) are climatically important trace gases that are produced by both nitrifying and den- itrifying bacteria-oxidizing bacteria, including Nitrosomonas and Nitrosococcus species (i.e., both b- and c-Proteobacterial ammonia

Ward, Bess

70

Dispersal of Aerobic Endospore-forming Bacteria from Soil and Agricultural Activities to Food and Feed  

Microsoft Academic Search

\\u000a For specific aerobic endospore-formers, the soil route of contamination or dispersal is the start of what is sometimes a long\\u000a series of events or processes in the agro-food chain that eventually leads to important problems or concerns for food safety\\u000a and\\/or quality. In the dairy sector, Bacillus cereus is the most important pathogen or spoilage organism that, through the faecal

Marc Heyndrickx

71

Comparison of Growth Rates of Aerobic Anoxygenic Phototrophic Bacteria and Other Bacterioplankton Groups in Coastal Mediterranean Waters?  

PubMed Central

Growth is one of the basic attributes of any living organism. Surprisingly, the growth rates of marine bacterioplankton are only poorly known. Current data suggest that marine bacteria grow relatively slowly, having generation times of several days. However, some bacterial groups, such as the aerobic anoxygenic phototrophic (AAP) bacteria, have been shown to grow much faster. Two manipulation experiments, in which grazing, viruses, and resource competition were reduced, were conducted in the coastal Mediterranean Sea (Blanes Bay Microbial Observatory). The growth rates of AAP bacteria and of several important phylogenetic groups (the Bacteroidetes, the alphaproteobacterial groups Roseobacter and SAR11, and the Gammaproteobacteria group and its subgroups the Alteromonadaceae and the NOR5/OM60 clade) were calculated from changes in cell numbers in the manipulation treatments. In addition, we examined the role that top-down (mortality due to grazers and viruses) and bottom-up (resource availability) factors play in determining the growth rates of these groups. Manipulations resulted in an increase of the growth rates of all groups studied, but its extent differed largely among the individual treatments and among the different groups. Interestingly, higher growth rates were found for the AAP bacteria (up to 3.71 day?1) and for the Alteromonadaceae (up to 5.44 day?1), in spite of the fact that these bacterial groups represented only a very low percentage of the total prokaryotic community. In contrast, the SAR11 clade, which was the most abundant group, was the slower grower in all treatments. Our results show that, in general, the least abundant groups exhibited the highest rates, whereas the most abundant groups were those growing more slowly, indicating that some minor groups, such the AAP bacteria, very likely contribute much more to the recycling of organic matter in the ocean than what their abundances alone would predict. PMID:21724878

Ferrera, Isabel; Gasol, Josep M.; Sebastiįn, Marta; Hojerovį, Eva; Koblķžek, Michal

2011-01-01

72

Aerobic bacteria from mucous membranes, ear canals, and skin wounds of feral cats in Grenada, and the antimicrobial drug susceptibility of major isolates  

Microsoft Academic Search

In a 2-year period 54 feral cats were captured in Grenada, West Indies, and a total of 383 samples consisting of swabs from rectum, vagina, ears, eyes, mouth, nose and wounds\\/abscesses, were cultured for aerobic bacteria and campylobacters. A total of 251 bacterial isolates were obtained, of which 205 were identified to species level and 46 to genus level. A

Harry Hariharan; Vanessa Matthew; Jacqueline Fountain; Alicia Snell; Devin Doherty; Brittany King; Eran Shemer; Simone Oliveira; Ravindra N. Sharma

2011-01-01

73

Comparative analysis of the diversity of aerobic spore-forming bacteria in raw milk from organic and conventional dairy farms.  

PubMed

Bacterial contamination of raw milk can originate from different sources: air, milking equipment, feed, soil, faeces and grass. It is hypothesized that differences in feeding and housing strategies of cows may influence the microbial quality of milk. This assumption was investigated through comparison of the aerobic spore-forming flora in milk from organic and conventional dairy farms. Laboratory pasteurized milk samples from five conventional and five organic dairy farms, sampled in late summer/autumn and in winter, were plated on a standard medium and two differential media, one screening for phospholipolytic and the other for proteolytic activity of bacteria. Almost 930 isolates were obtained of which 898 could be screened via fatty acid methyl ester analysis. Representative isolates were further analysed using 16S rRNA gene sequencing and (GTG)(5)-PCR. The majority of aerobic spore-formers in milk belonged to the genus Bacillus and showed at least 97% 16S rRNA gene sequence similarity with type strains of Bacillus licheniformis, Bacillus pumilus, Bacillus circulans, Bacillus subtilis and with type strains of species belonging to the Bacillus cereus group. About 7% of all isolates may belong to possibly new spore-forming taxa. Although the overall diversity of aerobic spore-forming bacteria in milk from organic vs. conventional dairy farms was highly similar, some differences between both were observed: (i) a relatively higher number of thermotolerant organisms in milk from conventional dairy farms compared to organic farms (41.2% vs. 25.9%), and (ii) a relatively higher number of B. cereus group organisms in milk from organic (81.3%) and Ureibacillus thermosphaericus in milk from conventional (85.7%) dairy farms. One of these differences, the higher occurrence of B. cereus group organisms in milk from organic dairy farms, may be linked to differences in housing strategy between the two types of dairy farming. However, no plausible clarification was found for the relatively higher number of thermotolerant organisms and the higher occurrence of U. thermosphaericus in milk from conventional dairy farms. Possibly this is due to differences in feeding strategy but no decisive indications were found to support this assumption. PMID:18406093

Coorevits, An; De Jonghe, Valerie; Vandroemme, Joachim; Reekmans, Rieka; Heyrman, Jeroen; Messens, Winy; De Vos, Paul; Heyndrickx, Marc

2008-06-01

74

Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria  

NASA Astrophysics Data System (ADS)

Manned Mars exploration requires recycle of materials to support human life A conceptual design is developed for space agriculture which is driven by the biologically regenerative function Hyper-thermophilic aerobic composting bacterial ecology is the core of materials recycling system to process human metabolic waste and inedible biomass and convert them to fertilizer for plants cultivation A photosynthetic reaction of plants will be driven by solar energy Water will be recycled by cultivation of plants and passing it through plant bodies Sub-surface water and atmospheric carbon dioxide are the natural resource available on Mars and these resources will be converted to oxygen and foods We envision that the agricultural system will be scaled up by importing materials from Martian environment Excess oxygen will be obtained from growing trees for structural and other components Minor elements including N P K and other traces will be introduced as fertilizers or nutrients into the agricultural materials circulation Nitrogen will be collected from Martian atmosphere We will assess biological fixation of nitrogen using micro-organisms responsible in Earth biosphere Hyper-thermophilic aerobic bacterial ecology is effective to convert waste materials into useful forms to plants This microbial technology has been well established on ground for processing sewage and waste materials For instance the hyper-thermophilic bacterial system is applied to a composting machine in a size of a trash box in home kitchen Since such a home electronics

Kanazawa, S.; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.; Space Agriculture Task Force, J.

75

Occurrence and activity of sulphate reducing bacteria in aerobic activated sludge systems.  

PubMed

In the sewage or wastewater treatment plant, biological sulphate reduction can occur spontaneously or be applied beneficially for its treatment. The results of this study can be applied to control SRB in the sewage and WWTP. Therefore, population diversity analyses of SRB for nine activated sludge wastewater treatment plants (WWTP) in the Netherlands and the effect of long-term (months) oxygen exposures on the SRB activity were carried out. T-RFLP and clone sequencing analyses of winter and summer samples revealed that (1) all WWTP have a similar SRB population, (2) there is no seasonal impact (10-20 °C) on the SRB population present in the WWTP and (3) Desulfobacter postgatei, Desulfovibrio desulfuricans and Desulfovibrio intestinalis were the most common and dominant SRB species observed in these samples, and origin from the sewage. Short term activity tests demonstrated that SRB were not active in the aerobic WWTP, but while flushed with N2-gas SRB became slightly active after 3 h. In a laboratory reactor at a dissolved oxygen concentration of <2 %, sulphate reduction occurred and 89 % COD removal was achieved. SRB grew in granules, in order to protect themselves for oxygen exposures. SRB are naturally present in aerobic WWTP, which is due to the formation of granules. PMID:25649202

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

2015-03-01

76

Colonization by aerobic bacteria in karst: Laboratory and in situ experiments  

USGS Publications Warehouse

Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton.

Personne, J.-C.; Poty, F.; Mahler, B.J.; Drogue, C.

2004-01-01

77

Lipid composition and vertical distribution of bacteria in aerobic sediments of the Venezuela Basin  

NASA Astrophysics Data System (ADS)

Box cores of surface (0 to 30-cm) sediments from carbonate, hemipelagic, and turbidite sediment types of the deep (3493 to 5039-m) Venezuelan Basin were analyzed to investigate the relationship between the vertical distribution of bacteria, lipids, lipid phosphate, and grain size. The polar lipid fraction was isolated chromatographically and quantified by flame-ionization detection using the Iatroscan TH-10 analyzer. Total bacterial abundance was measured by epifluorescence microscopy in sediments (0 to 20-cm) from the carbonate and turbidite sediments. In all three sediment types investigated, both total and polar lipid concentrations decreased with increasing depth in the sediment. The highest total and polar lipid concentrations were at the sediment-water interface (0 to 2-cm) of hemipelagic sediments (62.0 and 25.7 ?g g -1 dry sediment, respectively) followed by the carbonate and turbidite sediments. A similar decline in lipid phosphate was also observed. Bacterial abundance was > 5 × 10 8 bacteria (per gram dry sediment) at the sediment surface in both sediments examined and over 1 × 10 7 bacteria 20 cm below the sediment-water interface. Polar lipid and lipid phosphate concentrations did not appear to correlate with estimates of bacterial biomass, even in regions where bacteria were apparently the only organisms present.

Harvey, H. Rodger; Richardson, Michael D.; Patton, John S.

1984-04-01

78

Distribution of aerobic bacteria, protozoa, algae, and fungi in deep subsurface sediments  

Microsoft Academic Search

The distribution of microorganisms in deep subsurface profiles was determined at three sites at the Savannah River Plant, Aiken, South Carolina. Acridine orange direct counts (AODC) of bacteria were highest in surface soil samples and declined to the 10 to 10 per gram range in the subsurface, but then did not decline further with depth. In the subsurface, AODC values

J. L. Sinclair; W. C. Ghiorse

1989-01-01

79

Contribution of Aerobic Photoheterotrophic Bacteria to the Carbon Cycle in the Ocean  

Microsoft Academic Search

The vertical distribution of bacteriochlorophyll a, the numbers of infrared fluorescent cells, and the variable fluorescence signal at 880 nanometers wave- length, all indicate that photosynthetically competent anoxygenic phototrophic bacteria are abundant in the upper open ocean and comprise at least 11% of the total microbial community. These organisms are facultative photohetero- trophs, metabolizing organic carbon when available, but are

Zbigniew S. Kolber; F. Gerald Plumley; Andrew S. Lang; J. Thomas Beatty; Robert E. Blankenship; Cindy L. VanDover; Costantino Vetriani; Michal Koblizek; Christopher Rathgeber; Paul G. Falkowski

2001-01-01

80

Population of aerobic heterotrophic nitrogen-fixing bacteria associated with wetland and dryland rice  

Microsoft Academic Search

Nitrogen-fixing activity and populations of nitrogen-fixing bacteria associated with two varieties of rice grown in dryland and wetland conditions were measured at various growth stages during the dry season. Acetylene reduction activities were measured both in the field and for the hydroponically grown rice, which was transferred from the field to water culture 1 day before assay. The activities measured

W. L. Barraquio; M. R. De Guzman; M. Barrion; I. Watanahe

1982-01-01

81

Effect of selected monoterpenes on methane oxidation, denitrification, and aerobic metabolism by bacteria in pure culture.  

PubMed

Selected monoterpenes inhibited methane oxidation by methanotrophs (Methylosinus trichosporium OB3b, Methylobacter luteus), denitrification by environmental isolates, and aerobic metabolism by several heterotrophic pure cultures. Inhibition occurred to various extents and was transient. Complete inhibition of methane oxidation by Methylosinus trichosporium OB3b with 1.1 mM (-)-alpha-pinene lasted for more than 2 days with a culture of optical density of 0.05 before activity resumed. Inhibition was greater under conditions under which particulate methane monooxygenase was expressed. No apparent consumption or conversion of monoterpenes by methanotrophs was detected by gas chromatography, and the reason that transient inhibition occurs is not clear. Aerobic metabolism by several heterotrophs was much less sensitive than methanotrophy was; Escherichia coli (optical density, 0.01), for example, was not affected by up to 7.3 mM (-)-alpha-pinene. The degree of inhibition was monoterpene and species dependent. Denitrification by isolates from a polluted sediment was not inhibited by 3.7 mM (-)-alpha-pinene, gamma-terpinene, or beta-myrcene, whereas 50 to 100% inhibition was observed for isolates from a temperate swamp soil. The inhibitory effect of monoterpenes on methane oxidation was greatest with unsaturated, cyclic hydrocarbon forms [e.g., (-)-alpha-pinene, (S)-(-)-limonene, (R)-(+)-limonene, and gamma-terpinene]. Lower levels of inhibition occurred with oxide and alcohol derivatives [(R)-(+)-limonene oxide, alpha-pinene oxide, linalool, alpha-terpineol] and a noncyclic hydrocarbon (beta-myrcene). Isomers of pinene inhibited activity to different extents. Given their natural sources, monoterpenes may be significant factors affecting bacterial activities in nature. PMID:9464387

Amaral, J A; Ekins, A; Richards, S R; Knowles, R

1998-02-01

82

Aerobic Bacteria Cultured fromtheMouthoftheAmerican Opossum(Didelphis virginiana) withReference to  

Microsoft Academic Search

uri. Otherisolates included Neisseria spp., Acinetobacter calcoaceticus subsp. lwoffii, Aeromonas hydrophila, Citro- bacter freundii, Escherichia coli, Eikenella corrodens, Fla- vobacterium spp., Haemophilus spp., Oerskovia spp., Pseu- domonas spp.(not Pseudomonas aeruginosa), Bacillus spp., andCorynebacterium spp.Alphastreptococci wereabun- dantincultures fromallanimals. Bacillus spp.fromsix opossums exhibited moderate growth. Little growth ofE. coli wasdetected infive ofsevensubjects. Theremaining bacteria wereeachpresent inonlyoneortwoanimals exhibiting little growth. Eikenella corrodens (twoanimals)

Bacteria Associated; WILLIAMC. DALSEY

1990-01-01

83

Aerobic degradation of a mixture of azo dyes in a packed bed reactor having bacteria-coated laterite pebbles.  

PubMed

A microbial consortium capable of aerobic degradation of a mixture of azo dyes consisting of two isolated strains (RRL,TVM) and one known strain of Pseudomonas putida (MTCC 1194) was immobilized on laterite stones. The amount of bacterial biomass attached to the laterite stones was 8.64 g per 100 g of the stone on a dry weight basis. The packed bed reactor was filled with these stones and had a total capacity of 850 mL and a void volume of 210 mL. The feed consisted of an equal mixture of seven azo dyes both in water as well as in a simulated textile effluent, at a pH of 9.0 and a salinity of 900 mg/L. The dye concentrations of influent were 25, 50, and 100 microg/mL. The residence time was varied between 0.78 and 6.23 h. It was found that at the lowest residence time 23.55, 45.73, and 79.95 microg of dye was degraded per hour at an initial dye concentration of 25, 50, and 100 microg, respectively. The pH was reduced from 9.0 to 7.0. Simulated textile effluent containing 50 microg/mL dye was degraded by 61.7%. Analysis of degradation products by TLC and HPLC showed that the dye mixture was degraded to nontoxic smaller molecules. The bacteria-coated pebbles were stable, there was no washout even after 2 months, and the reactor was found to be suitable for the aerobic degradation of azo dyes. PMID:12675610

Senan, Resmi C; Shaffiqu, T S; Roy, J Jegan; Abraham, T Emilia

2003-01-01

84

Evaluation of an optical microbiological method for rapidly estimating populations of aerobic bacteria, coliforms, and Escherichia coli from ground pork.  

PubMed

The BioSys optical methods for estimating populations of aerobic bacteria, coliforms, and Escherichia coli from ground pork were evaluated. Ground pork samples were analyzed immediately, after temperature abuse at 25 degrees C for various periods of time, or after temperature abuse and dilution by mixing with pork that was prepared by grinding whole muscles that had the outer portion excised using a sterile scalpel. Each ground pork sample was tested using standard methods such as aerobic plate counts (APC), violet red bile (VRB) agar plate counts (coliforms), and three-tube most probable numbers (MPN--E. coli). Each sample was tested using the BioSys for total viable counts (TVC) by placing 2 ml of ground pork homogenate (25 g into 225 ml of sterile 1% buffered peptone water) into 8 ml of nutrient medium containing brom-cresol purple in a test vial and monitoring at 35 degrees C. Coliforms were enumerated by placing 5 ml of ground pork homogenate into 5 ml of coliform medium (CM) in a test vial and monitoring at 35 degrees C. E. coli were enumerated by placing 5 ml of ground pork homogenate into 5 ml of double-strength CM with 2% dextrose in a test vial and monitoring at 42 degrees C. The correlation coefficients for the regression lines comparing APC to BioSys TVC detection times (DT), VRB to BioSys coliform DT, and MPN to BioSys E. coli DT were -0.95, -0.94, and -0.93, and the line equations were logl0 CFU/ml = 8.94 - 0.40(DT), log10 CFU/ml = 8.77 - 0.43(DT), and log10 CFU/ml = 8.96 - 0.81(DT), respectively. These methods may allow pork producers to monitor equipment surfaces and products in less than 16 h and obtain microbiological results prior to shipment. PMID:11347998

Russell, S M

2001-05-01

85

Complete Genome Sequence of the Aerobic Marine Methanotroph Methylomonas methanica MC09  

SciTech Connect

Methylomonas methanica MC09 is a mesophilic, halotolerant, aerobic, methanotrophic member of the Gammaproteobacteria, isolated from coastal seawater. Here we present the complete genome sequence of this strain, the first available from an aerobic marine methanotroph.

Boden, Rich [University of Warwick, UK; Cunliffe, Michael [University of Warwick, UK; Scanlan, Julie [University of Warwick, UK; Moussard, Helene [University of Warwick, UK; Kits, K. Dimitri [University of Alberta, Edmondton, Canada; Klotz, Martin G [University of Louisville, Louisville; Jetten, MSM [Radboud University Nijmegen, The Netherlands; Vuilleumier, Stephane [University of Strasbourg; Han, James [U.S. Department of Energy, Joint Genome Institute; Peters, Lin [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Teshima, Hazuki [Los Alamos National Laboratory (LANL); Tapia, Roxanne [Los Alamos National Laboratory (LANL); Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Stein, Lisa Y. [University of Alberta, Edmondton, Canada; Murrell, Collin [University of Warwick, UK

2011-01-01

86

Population Changes in Enteric Bacteria and Other Microorganisms During Aerobic Thermophilic Windrow Composting1  

PubMed Central

Composting of wastes from swine feeding operations was studied. The effects of the frequency of turning the wastes and addition of straw to improve the physical structure were studied to determine the most effective technique to rapidly increase the temperature and, consequently, destroy coliforms and Salmonella. Four different treatments were studied; the results showed that, with addition of 5% (wt/wt) straw and mechanical turning of the compost 20 times per week, the temperature reached 60 C within 3 days and enteric bacteria were destroyed within 14 days. Images PMID:4203338

Savage, Jacob; Chase, Theodore; Macmillan, James D.

1973-01-01

87

Formation of Polyhydroxyalkanoate in Aerobic Anoxygenic Phototrophic Bacteria and Its Relationship to Carbon Source and Light Availability?  

PubMed Central

Aerobic anoxygenic phototrophic bacteria (AAPB) are unique players in carbon cycling in the ocean. Cellular carbon storage is an important mechanism regulating the nutrition status of AAPB but is not yet well understood. In this paper, six AAPB species (Dinoroseobacter sp. JL1447, Roseobacter denitrificans OCh 114, Roseobacter litoralis OCh 149, Dinoroseobacter shibae DFL 12T, Labrenzia alexandrii DFL 11T, and Erythrobacter longus DSMZ 6997) were examined, and all of them demonstrated the ability to form the carbon polymer polyhydroxyalkanoate (PHA) in the cell. The PHA in Dinoroseobacter sp. JL1447 was identified as poly-beta-hydroxybutyrate (PHB) according to evidence from Fourier transform infrared spectroscopy, differential scanning calorimetry, and 1H nuclear magnetic resonance spectroscopy examinations. Carbon sources turned out to be critical for PHA production in AAPB. Among the eight media tested with Dinoroseobacter sp. JL1447, sodium acetate, giving a PHA production rate of 72%, was the most productive carbon source, followed by glucose, with a 68% PHA production rate. Such PHA production rates are among the highest recorded for all bacteria. The C/N ratio of substrates was verified by the experiments as another key factor in PHA production. In the case of R. denitrificans OCh 114, PHA was not detected when the organism was cultured at C/N ratios of <2 but became apparent at C/N ratios of >3. Light is also important for the formation of PHA in AAPB. In the case of Dinoroseobacter sp. JL1447, up to a one-quarter increase in PHB production was observed when the culture underwent growth in a light-dark cycle compared to growth completely in the dark. PMID:21908634

Xiao, Na; Jiao, Nianzhi

2011-01-01

88

Enzyme activities of aerobic lignocellulolytic bacteria isolated from wet tropical forest soils.  

PubMed

Lignocellulolytic bacteria have promised to be a fruitful source of new enzymes for next-generation lignocellulosic biofuel production. Puerto Rican tropical forest soils were targeted because the resident microbes decompose biomass quickly and to near-completion. Isolates were initially screened based on growth on cellulose or lignin in minimal media. 75 Isolates were further tested for the following lignocellulolytic enzyme activities: phenol oxidase, peroxidase, ?-d-glucosidase, cellobiohydrolase, ?-xylopyranosidase, chitinase, CMCase, and xylanase. Cellulose-derived isolates possessed elevated ?-d-glucosidase, CMCase, and cellobiohydrolase activity but depressed phenol oxidase and peroxidase activity, while the contrary was true of lignin isolates, suggesting that these bacteria are specialized to subsist on cellulose or lignin. Cellobiohydrolase and phenol oxidase activity rates could classify lignin and cellulose isolates with 61% accuracy, which demonstrates the utility of model degradation assays. Based on 16S rRNA gene sequencing, all isolates belonged to phyla dominant in the Puerto Rican soils, Proteobacteria, Firmicutes, and Actinobacteria, suggesting that many dominant taxa are capable of the rapid lignocellulose degradation characteristic of these soils. The isolated genera Aquitalea, Bacillus, Burkholderia, Cupriavidus, Gordonia, and Paenibacillus represent rarely or never before studied lignolytic or cellulolytic species and were undetected by metagenomic analysis of the soils. The study revealed a relationship between phylogeny and lignocellulose-degrading potential, supported by Kruskal-Wallis statistics which showed that enzyme activities of cultivated phyla and genera were different enough to be considered representatives of distinct populations. This can better inform future experiments and enzyme discovery efforts. PMID:24238986

Woo, Hannah L; Hazen, Terry C; Simmons, Blake A; DeAngelis, Kristen M

2014-02-01

89

Effect of gamma Irradiation on the Microflora of Freshwater Fish: II. Generic Identification of Aerobic Bacteria from Yellow Perch Fillets.  

PubMed

Studies on the generic identification of bacteria isolated from nonirradiated and irradiated (0.3 and 0.6 Mrad) yellow perch fillets during the course of microbial spoilage have been conducted. After the enumeration and tabulation of macrocolonies on petri dish cultures obtained from fillets, isolates were examined and keyed out essentially according to modified morphological and biochemical protocols of Shewan. Identification was further confirmed through reference to Bergey's Manual. Data obtained from each isolate were coded and recorded on IBM cards to facilitate identification. Total aerobic microbial plate counts obtained from nonirradiated perch before storage ranged from 10 to 10 microorganisms per gram of fish. Organisms isolated from these fillets, in order of decreasing number, consisted of Achromobacter, Alcaligenes, Pseudomonas, Brevibacterium, Micrococcus, Flavobacterium, Bacillus, Sarcina, Microbacterium, Corynebacterium, yeasts, Lactobacillus, Vibrio, Aeromonas, and a few Proteus and Escherichia cells. During storage and as spoilage progressed, the flora shifted and the pseudomonads became predominant. Irradiation of fillets to 0.3 and 0.6 Mrad reduced the aforementioned flora to the Achromobacter-Alcaligenes group, which constituted the residual flora throughout fillet storage. PMID:16349702

Kazanas, N

1966-11-01

90

Microbiologically influenced corrosion of 304 stainless steel by aerobic Pseudomonas NCIMB 2021 bacteria: AFM and XPS study.  

PubMed

Microbiologically influenced corrosion (MIC) of stainless steel 304 by a marine aerobic Pseudomonas bacterium in a seawater-based medium was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM was used to observe in situ the proliferation of a sessile Pseudomonas cell by binary fission. The development of a biofilm on the coupon surface and the extent of corrosion damage beneath the biofilm after various exposure times were also characterized by AFM. Results showed that the biofilm formed on the coupon surface increased in thickness and heterogeneity with time, and thus resulting in the occurrence of extensive micro-pitting corrosion; whilst the depth of pits increased linearly with time. The XPS results confirmed that the colonization of Pseudomonas bacteria on the coupon surface induced subtle changes in the alloy elemental composition in the outermost layer of surface films. The most significant feature resulting from microbial colonization on the coupon surface was the depletion of iron (Fe) and the enrichment of chromium (Cr) content as compared to a control coupon exposed to the sterile medium, and the enrichment of Cr increased with time. These compositional changes in the main alloying elements may be correlated with the occurrence of extensive micropitting corrosion on the surface. PMID:17582747

Yuan, S J; Pehkonen, S O

2007-09-01

91

Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide- and metal-contaminated subsurface soils.  

PubMed

In this study, the immobilization of toxic uranium [U(VI)] mediated by the intrinsic phosphatase activities of naturally occurring bacteria isolated from contaminated subsurface soils was examined. The phosphatase phenotypes of strains belonging to the genera, Arthrobacter, Bacillus and Rahnella, previously isolated from subsurface soils at the US Department of Energy's (DOE) Oak Ridge Field Research Center (ORFRC), were determined. The ORFRC represents a unique, extreme environment consisting of highly acidic soils with co-occurring heavy metals, radionuclides and high nitrate concentrations. Isolates exhibiting phosphatase-positive phenotypes indicative of constitutive phosphatase activity were subsequently tested in U(VI) bioprecipitation assays. When aerobically grown in synthetic groundwater (pH 5.5) amended with 10 mM glycerol-3-phosphate (G3P), phosphatase-positive Bacillus and Rahnella spp. strains Y9-2 and Y9602 liberated sufficient phosphate to precipitate 73% and 95% of total soluble U added as 200 microM uranyl acetate respectively. In contrast, an Arthrobacter sp. X34 exhibiting a phosphatase-negative phenotype did not liberate phosphate from G3P or promote U(VI) precipitation. This study provides the first evidence of U(VI) precipitation via the phosphatase activity of naturally occurring Bacillus and Rahnella spp. isolated from the acidic subsurface at the DOE ORFRC. PMID:17991039

Martinez, Robert J; Beazley, Melanie J; Taillefert, Martial; Arakaki, Adrian K; Skolnick, Jeffrey; Sobecky, Patricia A

2007-12-01

92

Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden  

PubMed Central

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gram-negative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2–8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6 reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6 (MIC 8.6–17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2 and Co+2 but were extremely sensitive to Hg+2 followed by Cd+2, Mn+2 and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6 in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6 present in mine seepage when grown in mine seepage supplemented with VB concentrate. PMID:24159321

Dey, Satarupa; Paul, A.K.

2013-01-01

93

The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions  

NASA Astrophysics Data System (ADS)

M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for understanding natural mechanisms in soil and will be useful for the development of new soil models in laboratory. Thus, by means of «cascade filtration» method there've been made some results on true size, quantity and biomass of bacteria. Development of a bacteria in various soil horizons and their layers in aerobic and anaerobic conditions and calculations of biomass of bacteria in upper layer horizon A and lower layer horizon B have also become the subjects of the studies. It was identified that the quantity of bacteria in aerobic conditions increase during the microbial succession while bacteria sized 230 and 380 nm were dominating. In anaerobic conditions the process of connecting cells sized 170 nm and bacteria is observed. Biomass of bacteria is higher in anaerobic conditions in upper layer horizon A because of elevated variety of bacteria. In horizon B in anaerobic conditions it is of maximum because of anaerobic situation in situ. Thus, distribution of bacteria's size depends on aeration of soil. That helps to acknowledge the receipt of theory of a great number of researchers about that fact that the size of bacteria in the soil in anaerobic conditions decrease under stress-factors. This work touches upon such a poorly investigated subject as nanobacteria in the soil. But this knowledge plays a significant role in land reclamation oil-cut and prognostication pollution of the soil by pathogenic bacteria.

Gorbacheva, M.

2012-04-01

94

Effect of NaCl-tolerant lactic acid bacteria and NaCl on the fermentation characteristics and aerobic stability of silage.  

PubMed

NaCl-tolerant lactic acid bacteria (LAB) strains LC-10 (Lactobacillus casei) and LP-15 (Lact. plantarum) and NaCl were used as additives to sorghun (Sorghum bicolor). Numbers of LAB were significantly (P < 0.05) higher in all the additive-treated silages than in the control silage at an early stage of ensiling. During the fermentation process, addition of NaCl or LAB effectively inhibited the growth of aerobic bacteria and clostridia, but not yeasts. All the additive-treated silages had significantly (P < 0.05) lower pH, ammonia nitrogen content, dry matter loss and gas production but significantly (P < 0.05) higher lactic acid content and residual water soluble carbohydrates compared with the control silage. The improvement in silage quality was in the order: LAB > NaCl > control. Yeast counts were high in all additive-based silages and they increased during the exposure of the silages to air. As a result, these silages suffered aerobic deterioration, whereas the control silage was stable. The results confirmed that the NaCl or LAB improved fermentation quality but did not prevent aerobic deterioration of the silage. PMID:9351210

Cai, Y; Ohmomo, S; Ogawa, M; Kumai, S

1997-09-01

95

Biochemistry and biotechnology of mesophilic and thermophilic nitrile metabolizing enzymes  

Microsoft Academic Search

Mesophilic nitrile-degrading enzymes are widely dispersed in the Bacteria and lower orders of the eukaryotic kingdom. Two\\u000a distinct enzyme systems, a nitrilase catalyzing the direct conversion of nitriles to carboxylic acids and separate but cotranscribed\\u000a nitrile hydratase and amidase activities, are now well known. Nitrile hydratases are metalloenzymes, incorporating FeIII or CoII ions in thiolate ligand networks where they function

Don Cowan; Rebecca Cramp; Rui Pereira; Dan Graham; Qadreyah Almatawah

1998-01-01

96

Mesophilic lactobacilli in Fiore Sardo cheese: PCR-identification and evolution during cheese ripening  

Microsoft Academic Search

The mesophilic lactobacilli colonizing Fiore Sardo ewe's milk cheese were characterized. They seemed to be the dominant non-starter lactic acid bacteria composing its natural microflora, with a viable cell number varying from 105CFUg?1 (1-day-old cheese) to 108CFUg?1 (30-day-old cheese) and then slowly decreasing up to 104CFUg?1 after 7 months’ ripening. Considering the relevance of mesophilic lactobacilli in affecting the cheese

Luisa Mannu; Roberta Comunian; Maria Francesca Scintu

2000-01-01

97

Effect of applying lactic acid bacteria isolated from forage crops on fermentation characteristics and aerobic deterioration of silage.  

PubMed

Two selected strains, Lactobacillus casei FG 1 and Lactobacillus plantarum FG 10 that were isolated from forage crops were used as additives at 1.0 x 10(5) cfu/g of fresh matter to alfalfa, Italian ryegrass, and sorghum, and their effect on fermentation characteristics and aerobic deterioration of silage was studied. The three silages treated with strains FG 1 or FG 10 were well preserved; had significantly lower pH values, butyric acid, propionic acid, and ammonia N concentrations, gas production, and dry matter losses; and had significantly higher contents of residual water-soluble carbohydrates and lactic acid than did the respective control silages. Yeast counts were high in all treated silages and increased rapidly during aerobic exposure. As a result, treated silages spoiled faster upon aerobic exposure than did the respective control silages. Most yeasts isolated from deteriorated silages showed high tolerance to lactic acid but low tolerance to butyric acid, and they were able to grow at low pH conditions and assimilate lactic acid. The results confirmed that L. casei and L. plantarum improved fermentation quality but did not inhibit the growth of silage yeast or aerobic deterioration of the silage. PMID:10194670

Cai, Y; Benno, Y; Ogawa, M; Kumai, S

1999-03-01

98

ISOLATIONS OF AEROBIC BACTERIA FROM WILD DESERT BIGHORN SHEEP (OVIS CANADENSIS NELSON! AND 0. C. MEX!CANA) IN ARIZONA  

Microsoft Academic Search

Nasal, pharyngeal, cervical and vaginal swab specimens were obtained from 74 desert bighorn sheep for the purpose of investigating the normal aerobic bacterial flora of wild sheep. A total of 281 isolates was obtained and identified by standard microbiologic tests. One hundred seven of these isolates were gram positive and included Bacillus sp. (36%.), Staphylococcus epiderrnidis (8%), S. aureus (4%),

M. M. Marshall; J. Glenn Songer; C. J. Chilelli

99

Thermophilic aerobic biological wastewater treatment  

Microsoft Academic Search

The following review article will serve to elucidate the existing state-of-the-art and breadth of technical understanding related to thermophilic aerobic biological wastewater treatment. The advantages of this technology include rapid biodegradation rates, low sludge yields, and excellent process stability. Substrate utilization rates reported in the technical literature are 3–10 times greater than that observed with analogous mesophilic processes, and sludge

Timothy M LaPara; James E Alleman

1999-01-01

100

Se (IV) triggers faster Te (IV) reduction by soil isolates of heterotrophic aerobic bacteria: formation of extracellular SeTe nanospheres.  

PubMed

BackgroundSelenium and Tellurium have many common chemical properties as both belong to group 16 of the periodic table. High toxicities of Se and Te oxyanions cause environmental problems in contaminated soils and waters. Three strains (C4, C6 and C7) of selenite reducing and nanoparticle forming aerobic bacteria which were isolated from agricultural soils of India containing high concentrations of Se were investigated after 3.5 months of freeze-storage for their resistance against the toxic oxyanion tellurite and its reduction to non toxic elemental form Te0 as well as nanoparticles formation.ResultsStrains C4, C6 and C7 reduced tellurite at maximum reduction rates of 2.3, 1.5 and 2.1 mg Te (IV)/L/d, respectively and produced extracellular Te0 nanospheres as revealed from SEM-EDX analysis. Production of extracellular Te nanospheres has been described seldom. Further, concurrent reduction of both selenite and tellurite by bacteria was examined as these toxic oxyanions are often present together in natural environments, mine tailings or wastewater from copper refining. Interestingly, bioreduction of 100 mg/L selenite in shake flasks was not much affected by the presence of 10 mg/L tellurite but tellurite reduction rate increased 13 fold with selenite in the medium. The concurrent reduction of these oxyanions resulted in rarely described bioformation of extracellular nanoparticles composed of both Se and Te, reported first time for aerobically growing heterotrophic non-halophilic bacterial cultures. Duganella violacienigra, the closely related strain to C4 was also found to be resistant to oxyanions of Se and Te.ConclusionsSelenite reducing heterotrophic non-halophilic aerobic bacteria revived from 3.5 months freeze storage could successfully reduce toxic tellurite to non toxic elemental form and produced extracellular nanospheres during detoxification. Presence of relatively less toxic selenite in the medium triggers bioreduction of more toxic tellurite leading to formation of extracellular SeTe nanospheres which are sought by solar and optical recording media industry because of their excellent photovoltaic and optical properties. The bacterial cultures investigated in this study could be exploited commercially to remediate not only selenite and tellurite-contaminated soil and water but also for green synthesis of extracellular Se, Te and Seæ+æTe nanospheres. PMID:25425453

Bajaj, Mini; Winter, Josef

2014-11-26

101

Iodide accumulation by aerobic bacteria isolated from subsurface sediments of a 129I-contaminated aquifer at the Savannah River site, South Carolina.  

PubMed

(129)I is of major concern because of its mobility in the environment, excessive inventory, toxicity (it accumulates in the thyroid), and long half-life (?16 million years). The aim of this study was to determine if bacteria from a (129)I-contaminated oxic aquifer at the F area of the U.S. Department of Energy's Savannah River Site, SC, could accumulate iodide at environmentally relevant concentrations (0.1 ?M I(-)). Iodide accumulation capability was found in 3 out of 136 aerobic bacterial strains isolated from the F area that were closely related to Streptomyces/Kitasatospora spp., Bacillus mycoides, and Ralstonia/Cupriavidus spp. Two previously described iodide-accumulating marine strains, a Flexibacter aggregans strain and an Arenibacter troitsensis strain, accumulated 2 to 50% total iodide (0.1 ?M), whereas the F-area strains accumulated just 0.2 to 2.0%. Iodide accumulation by FA-30 was stimulated by the addition of H(2)O(2), was not inhibited by chloride ions (27 mM), did not exhibit substrate saturation kinetics with regard to I(-) concentration (up to 10 ?M I(-)), and increased at pH values of <6. Overall, the data indicate that I(-) accumulation likely results from electrophilic substitution of cellular organic molecules. This study demonstrates that readily culturable, aerobic bacteria of the F-area aquifer do not accumulate significant amounts of iodide; however, this mechanism may contribute to the long-term fate and transport of (129)I and to the biogeochemical cycling of iodine over geologic time. PMID:21278282

Li, Hsiu-Ping; Brinkmeyer, Robin; Jones, Whitney L; Zhang, Saijin; Xu, Chen; Schwehr, Kathy A; Santschi, Peter H; Kaplan, Daniel I; Yeager, Chris M

2011-03-01

102

Iodide Accumulation by Aerobic Bacteria Isolated from Subsurface Sediments of a 129I-Contaminated Aquifer at the Savannah River Site, South Carolina ?  

PubMed Central

129I is of major concern because of its mobility in the environment, excessive inventory, toxicity (it accumulates in the thyroid), and long half-life (?16 million years). The aim of this study was to determine if bacteria from a 129I-contaminated oxic aquifer at the F area of the U.S. Department of Energy's Savannah River Site, SC, could accumulate iodide at environmentally relevant concentrations (0.1 ?M I?). Iodide accumulation capability was found in 3 out of 136 aerobic bacterial strains isolated from the F area that were closely related to Streptomyces/Kitasatospora spp., Bacillus mycoides, and Ralstonia/Cupriavidus spp. Two previously described iodide-accumulating marine strains, a Flexibacter aggregans strain and an Arenibacter troitsensis strain, accumulated 2 to 50% total iodide (0.1 ?M), whereas the F-area strains accumulated just 0.2 to 2.0%. Iodide accumulation by FA-30 was stimulated by the addition of H2O2, was not inhibited by chloride ions (27 mM), did not exhibit substrate saturation kinetics with regard to I? concentration (up to 10 ?M I?), and increased at pH values of <6. Overall, the data indicate that I? accumulation likely results from electrophilic substitution of cellular organic molecules. This study demonstrates that readily culturable, aerobic bacteria of the F-area aquifer do not accumulate significant amounts of iodide; however, this mechanism may contribute to the long-term fate and transport of 129I and to the biogeochemical cycling of iodine over geologic time. PMID:21278282

Li, Hsiu-Ping; Brinkmeyer, Robin; Jones, Whitney L.; Zhang, Saijin; Xu, Chen; Schwehr, Kathy A.; Santschi, Peter H.; Kaplan, Daniel I.; Yeager, Chris M.

2011-01-01

103

Multicenter Evaluation of the Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Gram-Positive Aerobic Bacteria  

PubMed Central

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261

Burnham, Carey-Ann D.; Bythrow, Maureen; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Procop, Gary W.; Richter, Sandra S.; Sercia, Linda; Westblade, Lars F.; Ferraro, Mary Jane; Branda, John A.

2013-01-01

104

INACTIVATION OF ENTERIC PATHOGENS DURING AEROBIC DIGESTION OF WASTEWATER SLUDGE  

EPA Science Inventory

The effects of aerobic and anaerobic digestion on enteric viruses, enteric bacteria, total aerobic bacteria, and intestinal parasites were studied under laboratory and field conditions. Under laboratory conditions, the temperature of the sludge digestion was the major factor infl...

105

Comparison of two transport systems available in Japan (TERUMO kenkiporter II and BBL Port-A-Cul) for maintenance of aerobic and anaerobic bacteria.  

PubMed

The kenkiporter II (KP II) transport system is commonly used in many hospitals in Japan for transporting bacterial specimens to microbiology laboratories. Recently, the BBL Port-A-Cul (PAC) fluid vial became available. However, no reports thus far have compared the effectiveness of these two transport systems. We chose 4 aerobic and facultative anaerobic bacteria as well as 8 anaerobic organisms, and prepared three strains of each bacterium in culture media for placement into PAC and KP II containers. We compared the effectiveness of each transport system for preserving each organism at 6, 24, and 48 h after inoculation at room temperature. Thirty-six strains out of 12 bacteria were used in this study. The PAC system yielded better recovery in quantity of organisms than the KP II system at 6, 24 and 48 h. More strains were significantly recovered with the PAC system than with the KP II at 24 h (36/36 vs. 23/36, P < 0.001) and 48 h (30/36 vs. 12/36, P < 0.001). The PAC system was better in the recovery of viable organisms counted at 24 and 48 h after inoculation compared with the KP II system. The PAC system may be recommended for the transfer of bacterial specimens in clinical settings. PMID:24462420

Fujimoto, Daichi; Takegawa, Hiroshi; Doi, Asako; Sakizono, Kenji; Kotani, Yoko; Miki, Kanji; Naito, Takuya; Niki, Marie; Miyamoto, Junko; Tamai, Koji; Nagata, Kazuma; Nakagawa, Atsushi; Tachikawa, Ryo; Otsuka, Kojiro; Katakami, Nobuyuki; Tomii, Keisuke

2014-01-01

106

Dai nippon printing co., ltd, Medi-Ca AC for enumeration of aerobic bacteria. Performance tested method 041302.  

PubMed

A ready-made dry medium method for aerobic count, the MediCa AC method, was compared to the AOAC Official Method 966.23, Microbiological Methods, for seven different heat-processed meat matrixes: cooked roast beef, Chinese barbecued pork (barbecued pork seasoned with honey-based sauce), bacon, cooked ham, frankfurter (made from beef and pork), and boiled and cooked pork sausage. The 95% confidence interval for the mean difference between the two methods at each contamination level for each matrix fell within the range of -0.50 to 0.50, and no statistical difference was observed at all three contamination levels for five matrixes. These results demonstrate that the Medi-Ca AC method is a reasonable alternative to the AOAC 966.23 method for cooked meat products. PMID:25051632

Okochi, Norihiko; Yamazaki, Mamoru; Kiso, Shoichi; Kinoshita, Mai; Okita, Yurie; Kazama, Keisuke; Saito, Rui

2014-01-01

107

Effect of Time and Sand Abrasion on Recovery of Aerobic Bacteria, Escherichia coli, and Coliforms from Broiler Carcasses  

Technology Transfer Automated Retrieval System (TEKTRAN)

An experiment was conducted to determine the effect of rinse time and a sand abrasion on bacteria from whole broiler carcass rinses (WCR). Twelve eviscerated broiler carcasses were obtained from a commercial processing plant prior to chilling. Six carcasses were rinsed in 400 mL of 2.0% buffered pe...

108

Aerobic Biodegradation of Methyl tert-Butyl Ether by Aquifer Bacteria from Leaking Underground Storage Tank Sites  

PubMed Central

The potential for aerobic methyl tert-butyl ether (MTBE) degradation was investigated with microcosms containing aquifer sediment and groundwater from four MTBE-contaminated sites characterized by oxygen-limited in situ conditions. MTBE depletion was observed for sediments from two sites (e.g., 4.5 mg/liter degraded in 15 days after a 4-day lag period), whereas no consumption of MTBE was observed for sediments from the other sites after 75 days. For sediments in which MTBE was consumed, 43 to 54% of added [U-14C]MTBE was mineralized to 14CO2. Molecular phylogenetic analyses of these sediments indicated the enrichment of species closely related to a known MTBE-degrading bacterium, strain PM1. At only one site, the presence of water-soluble gasoline components significantly inhibited MTBE degradation and led to a more pronounced accumulation of the metabolite tert-butyl alcohol. Overall, these results suggest that the effects of oxygen and water-soluble gasoline components on in situ MTBE degradation will vary from site to site and that phylogenetic analysis may be a promising predictor of MTBE biodegradation potential. PMID:11722940

Kane, S. R.; Beller, H. R.; Legler, T. C.; Koester, C. J.; Pinkart, H. C.; Halden, R. U.; Happel, A. M.

2001-01-01

109

Enrichment and characterization of a bacteria consortium capable of heterotrophic nitrification and aerobic denitrification at low temperature.  

PubMed

Nitrogen removal in wastewater treatment plants is usually severely inhibited under cold temperature. The present study proposes bioaugmentation using psychrotolerant heterotrophic nitrification-aerobic denitrification consortium to enhance nitrogen removal at low temperature. A functional consortium has been successfully enriched by stepped increase in DO concentration. Using this consortium, the specific removal rates of ammonia and nitrate at 10 °C reached as high as 3.1 mg N/(gSSh) and 9.6 mg N/(gSSh), respectively. PCR-DGGE and clone library analysis both indicated a significant reduction in bacterial diversity during enrichment. Phylogenetic analysis based on nearly full-length 16S rRNA genes showed that Alphaproteobacteria, Deltaproteobacteria and particularly Bacteroidetes declined while Gammaproteobacteria (all clustered into Pseudomonas sp.) and Betaproteobacteria (mainly Rhodoferax ferrireducens) became dominant in the enriched consortium. It is likely that Pseudomonas spp. played a major role in nitrification and denitrification, while R. ferrireducens and its relatives utilized nitrate as both electron acceptor and nitrogen source. PMID:23131636

Yao, Shuo; Ni, Jinren; Chen, Qian; Borthwick, Alistair G L

2013-01-01

110

Low Probability of Initiating nirS Transcription Explains Observed Gas Kinetics and Growth of Bacteria Switching from Aerobic Respiration to Denitrification  

PubMed Central

In response to impending anoxic conditions, denitrifying bacteria sustain respiratory metabolism by producing enzymes for reducing nitrogen oxyanions/-oxides (NOx) to N2 (denitrification). Since denitrifying bacteria are non-fermentative, the initial production of denitrification proteome depends on energy from aerobic respiration. Thus, if a cell fails to synthesise a minimum of denitrification proteome before O2 is completely exhausted, it will be unable to produce it later due to energy-limitation. Such entrapment in anoxia is recently claimed to be a major phenomenon in batch cultures of the model organism Paracoccus denitrificans on the basis of measured e?-flow rates to O2 and NOx. Here we constructed a dynamic model and explicitly simulated actual kinetics of recruitment of the cells to denitrification to directly and more accurately estimate the recruited fraction (). Transcription of nirS is pivotal for denitrification, for it triggers a cascade of events leading to the synthesis of a full-fledged denitrification proteome. The model is based on the hypothesis that nirS has a low probability (, h?1) of initial transcription, but once initiated, the transcription is greatly enhanced through positive feedback by NO, resulting in the recruitment of the transcribing cell to denitrification. We assume that the recruitment is initiated as [O2] falls below a critical threshold and terminates (assuming energy-limitation) as [O2] exhausts. With ?=?0.005 h?1, the model robustly simulates observed denitrification kinetics for a range of culture conditions. The resulting (fraction of the cells recruited to denitrification) falls within 0.038–0.161. In contrast, if the recruitment of the entire population is assumed, the simulated denitrification kinetics deviate grossly from those observed. The phenomenon can be understood as a ‘bet-hedging strategy’: switching to denitrification is a gain if anoxic spell lasts long but is a waste of energy if anoxia turns out to be a ‘false alarm’. PMID:25375393

Hassan, Junaid; Bergaust, Linda L.; Wheat, I. David; Bakken, Lars R.

2014-01-01

111

Low probability of initiating nirS transcription explains observed gas kinetics and growth of bacteria switching from aerobic respiration to denitrification.  

PubMed

In response to impending anoxic conditions, denitrifying bacteria sustain respiratory metabolism by producing enzymes for reducing nitrogen oxyanions/-oxides (NOx) to N2 (denitrification). Since denitrifying bacteria are non-fermentative, the initial production of denitrification proteome depends on energy from aerobic respiration. Thus, if a cell fails to synthesise a minimum of denitrification proteome before O2 is completely exhausted, it will be unable to produce it later due to energy-limitation. Such entrapment in anoxia is recently claimed to be a major phenomenon in batch cultures of the model organism Paracoccus denitrificans on the basis of measured e(-)-flow rates to O2 and NOx. Here we constructed a dynamic model and explicitly simulated actual kinetics of recruitment of the cells to denitrification to directly and more accurately estimate the recruited fraction (Fden). Transcription of nirS is pivotal for denitrification, for it triggers a cascade of events leading to the synthesis of a full-fledged denitrification proteome. The model is based on the hypothesis that nirS has a low probability (rden, h(-1)) of initial transcription, but once initiated, the transcription is greatly enhanced through positive feedback by NO, resulting in the recruitment of the transcribing cell to denitrification. We assume that the recruitment is initiated as [O2] falls below a critical threshold and terminates (assuming energy-limitation) as [O2] exhausts. With rden?=?0.005 h(-1), the model robustly simulates observed denitrification kinetics for a range of culture conditions. The resulting Fden (fraction of the cells recruited to denitrification) falls within 0.038-0.161. In contrast, if the recruitment of the entire population is assumed, the simulated denitrification kinetics deviate grossly from those observed. The phenomenon can be understood as a 'bet-hedging strategy': switching to denitrification is a gain if anoxic spell lasts long but is a waste of energy if anoxia turns out to be a 'false alarm'. PMID:25375393

Hassan, Junaid; Bergaust, Linda L; Wheat, I David; Bakken, Lars R

2014-11-01

112

Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.  

PubMed

The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. PMID:19959355

Dumas, C; Perez, S; Paul, E; Lefebvre, X

2010-04-01

113

Aerobic Metabolism 1 AEROBIC RESPIRATION  

E-print Network

Aerobic Metabolism 1 AEROBIC RESPIRATION 1 Review; In the last set of notes we learned some of the basic types of reactions involved in cellular work and energy conservation. Recall that we focused on it aerobic respiration. In these notes we will consider the specific processes that use O2 plus high

Prestwich, Ken

114

Characterization of subterranean bacteria in the Hungarian Upper Permian Siltstone (Aleurolite) Formation.  

PubMed

The main purpose of this work was to study the microbiology of the Hungarian Upper Permian Siltstone (Aleurolite) Formation, to assess the safety of future underground repositories for nuclear waste. Sixty-seven air, groundwater, technical water, rock, and surface samples were collected aseptically from different depths. The number of aerobic and anaerobic isolates was 277. The mesophilic minimum and maximum CFU counts of the air samples were 1.07-5.84 x 10(2).mL-1 (aerobic) and 0.22-1.04 x 10(2).mL-1 (anaerobic), respectively; those of the water samples were 0.39-1.25 x 10(5).mL-1 (aerobic) and 0.36-3.9 x 10(3).mL-1 (anaerobic); those of the technical water samples were 0.27-5.03 x 10(6).mL-1 (aerobic) and 4 x 10(5)-->10(6).mL-1 (anaerobic); and those of the aleurolite samples were 2.32 x 10(2)-2.47 x 10(5).g-1 (aerobic) and 0.45-9.5 x 10(2).g-1 (anaerobic). In the groundwater, the thermophilic aerobic bacteria count was 0-2.4 x 10(2).mL-1 and the thermophilic anaerobic bacteria count was 0.43-4.6 x 10(4).mL-1. The gases produced by the 16 gas-forming isolates were CO2 (aerobic isolates), and CO2 and H2 (anaerobic isolates). About 20% of the aerobic isolates produced siderophores. The proportions of organic acid producers were lowest in aerobic and anaerobic isolates from the aleurolite, 13% and 14%, respectively. The highest proportions of acid producers in the aerobic and anaerobic isolates from the air samples were 63% and 54%. Altogether 160 of the aerobic isolates and 52 of the anaerobic isolates were spore formers. The radiosensitivity of the aerobic isolates was also determined; the D10 values of the sporeformers ranged between 0.8-2.44 kGy. Our results indicate that the sulfate-reducing bacteria and the production of complexing agents (siderophores) may contribute to the mobilization of radionuclides from underground repositories. As well, microbial gas production can influence the environmental conditions. The variability in bacterial radiotolerance indicates the biodiversity at this potential disposal site. These facts must be considered during the planning of a nuclear waste repository. PMID:10913978

Farkas, G; Gazsó, L G; Diósi, G

2000-06-01

115

Adaptation of mesophilic anaerobic sewage fermentor populations to thermophilic temperatures  

SciTech Connect

Thermophilic (50/sup 0/ ) and obligately thermophilic (60/sup 0/C) anaerobic carbohydrate- and protein-digesting and methanogenic bacterial populations were enumerated in a mesophilic (35/sup 0/C) fermentor anaerobically digesting municipal primary sludge. Of the total population in the mesophilic fermentor, 9% were thermophiles and 1% were obligate thermophiles. Of these 10%, the percentages of bacteria (thermophiles and obligate thermophiles, respectively) able to use specific substrates were as follows: bacteria able to digest albumin, casein, starch, and mono- and disaccharides, 30 and 10%; pectin degraders, 10 and 0.2%; cellulose degraders, 2 and 0.06%; methanogens that grow with H/sub 2/ and CO/sub 2/, methanol, and dimethylamine, 9 and 1%; methanogens that grow with formate, 8 and 5%; and methanogens that grow with acetate, 25 and less than 0.8%. Shortly after the temperature was elevated from 35 to 50 or 60 degrees C, the digestion of albumin, casein, starch, and mono- and disaccharides was detected, and methane was produced from H/sub 2/ and CO/sub 2/. Methane produced from acetate was not delayed at 50 degrees C, but was delayed by 29 days at 60 degrees C. Methane produced from formate was delayed by 3 days, from methanol by 7 days, and from dimethylamine by 5 days at 50 and 60 degrees C. A 10- and 20-day acclimation period was required for hydrolysis of pectin and cellulose, respectively, at 50 degrees C. Digestion of pectin required 20 days and cellulose longer than 85 days when the temperature was elevated abruptly from 35 to 60 degrees C. The acclimation period for the digestion of pectin and cellulose at 60 degrees C was shortened to 3 and 15 days, respectively, by seeding with a small amount of a culture acclimated to 50 degrees C. The data suggest that enrichment of cellulolytic, pectinolytic, and acetate-utilizing bacteria is crucial for the digestion of sewage sludge at 60 degrees C. (Refs. 17).

Chen, M.

1983-04-01

116

Lab scale experiments using a submerged MBR under thermophilic aerobic conditions for the treatment of paper mill deinking wastewater.  

PubMed

This paper describes the results of laboratory experiments using a thermophilic aerobic MBR (TMBR) at 50 °C. An innovative use of submerged flat-sheet MBR modules to treat circuit wastewater from the paper industry was studied. Two experiments were conducted with a flux of 8-13 L/m(2)/h without chemical membrane cleaning. COD and BOD(5) elimination rates were 83% and 99%, respectively. Calcium was reduced from 110 to 180 mg/L in the inflow to 35-60 mg/L in the permeate. However, only negligible membrane scaling occurred. The observed sludge yield was very low and amounted to 0.07-0.29 g MLSS/g COD(eliminated). Consequently, the nutrient supply of ammonia and phosphate can be lower compared to a mesophilic process. Molecular-biological FISH analysis revealed a likewise high diversity of microorganisms in the TMBR compared to the mesophilic sludge used for start-up. Furthermore, ammonia-oxidising bacteria were detected at thermophilic operation. PMID:22595101

Simstich, Benjamin; Beimfohr, Claudia; Horn, Harald

2012-10-01

117

Searching for Mesophilic Thermotogales Bacteria: “Mesotogas” in the Wild? †  

PubMed Central

All cultivated Thermotogales are thermophiles or hyperthermophiles. However, optimized 16S rRNA primers successfully amplified Thermotogales sequences from temperate hydrocarbon-impacted sites, mesothermic oil reservoirs, and enrichment cultures incubated at <46°C. We conclude that distinct Thermotogales lineages commonly inhabit low-temperature environments but may be underreported, likely due to “universal” 16S rRNA gene primer bias. PMID:20495053

Nesbų, Camilla L.; Kumaraswamy, Rajkumari; Dlutek, Marlena; Doolittle, W. Ford; Foght, Julia

2010-01-01

118

Survival of Aerobic and Anaerobic Bacteria in Purulent Clinical Specimens Maintained in the Copan Venturi Transystem and Becton Dickinson Port-a-Cul Transport Systems  

Microsoft Academic Search

Protection of anaerobic bacteria from exposure to oxygen during the transport of clinical specimens to the laboratory is crucial for the survival of these organisms. Because the use of swabs may encourage collection of superficial specimens that represent colonizing bacteria instead of the etiologic agents found deeper in the infected tissues, aspirates have always been preferable to swab systems for

DIANE M. CITRON; YUMI A. WARREN; MARIE K. HUDSPETH; ELLIE J. C. GOLDSTEIN

2000-01-01

119

Comparison of the BACTEC MYCO/F Lytic bottle to the isolator tube, BACTEC Plus Aerobic F/bottle, and BACTEC Anaerobic Lytic/10 bottle and comparison of the BACTEC Plus Aerobic F/bottle to the Isolator tube for recovery of bacteria, mycobacteria, and fungi from blood.  

PubMed

The BACTEC MYCO/F Lytic blood culture bottle (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is designed to optimize the recovery of fungi and mycobacteria; however, this bottle also supports the growth of most aerobic bacteria. We compared the MYCO/F Lytic bottle with two other BACTEC bottles and the Isolator system for the recovery of bacteria as well as fungi and mycobacteria from blood. A total of 6,108 blood culture sets were inoculated with blood obtained from adult patients. Twenty-five to 28 ml of blood collected by a phlebotomy team for each blood culture set was randomly distributed into each of four blood culture receptacles: the Isolator tube (Wampole Laboratories, Cranbury, N.J.) and three BACTEC bottles: the MYCO/F Lytic bottle, the BACTEC Plus Aerobic/F bottle, and the BACTEC Anaerobic Lytic/10 bottle. The sediment from the Isolator tube was inoculated onto chocolate agar (CA), brain heart infusion agar (BHI), and Sabouraud dextrose agar (SDA) and into a BACTEC 13A bottle. Incubation durations were as follows: MYCO/F Lytic bottle, 42 days; Plus Aerobic/F bottle, 5 days; Anaerobic Lytic/10 bottle, 5 days; sediment from Isolator tube on CA, 3 days; sediment from Isolator tube on BHI, 30 days; sediment from Isolator tube on SDA, 30 days; and sediment from Isolator tube in a BACTEC 13A bottle, 42 days. Two isolates of Histoplasma capsulatum were recovered from the Isolator tube only. Three isolates of Mycobacterium tuberculosis complex were recovered: two isolates from the MYCO/F Lytic bottle only and one isolate from the Isolator tube (whose sediment was inoculated into the BACTEC 13A bottle) only. Two isolates of Cryptococcus neoformans were recovered: one from the MYCO/F Lytic bottle only and the other from the MYCO/F Lytic bottle and the Isolator tube (whose sediment was inoculated into the BACTEC 13A bottle). For potential pathogens overall, there was a statistical difference in recovery that favored the Isolator system over the MYCO/F Lytic bottle (P = 0.0015), including statistically significant differences for Staphylococcus aureus (P = 0.0001) and Streptococcus pneumoniae (P = 0.0313). However, there was no statistically significant difference between the two blood culture systems when detection of bloodstream infection was considered. The time to detection for all potential pathogens combined was less for the MYCO/F Lytic bottle than for the Isolator system (P = 0.0004). Overall, the potential pathogen recovery was greater for the BACTEC Plus Aerobic/F bottle than for either the Isolator system (P = 0.0003) or the MYCO/F Lytic bottle (P = 0.0001). However, the BACTEC Plus Aerobic/F bottle did not recover M. tuberculosis, H. capsulatum, or C. neoformans isolates. The combination of the Isolator system and MYCO/F Lytic bottle may be useful as a selective blood culture method to optimize the recovery of fungi and mycobacteria from blood. Compared with the manual Isolator system, the MYCO/F Lytic system has the advantage of less preanalytic processing and continuous automated monitoring of bottles for growth by the BACTEC 9240 instrument. PMID:11724848

Vetter, E; Torgerson, C; Feuker, A; Hughes, J; Harmsen, S; Schleck, C; Horstmeier, C; Roberts, G; Cockerill, F

2001-12-01

120

Antibacterial action of essential oils of Artemisia as an ecological factor. I. Antibacterial action of the volatile oils of Artemisia tridentata and Artemisia nova on aerobic bacteria.  

PubMed

Bacterial response to increasing amounts of the volatile oils varies significantly according to species of bacteria tested. Among the four species examined, Escherichia coli was the most resistant to the oils, followed by Neisseria sicca, Bacillus subtilis, and Staphylococcus aureus. The oils of Artemisia tridentata seem to have the same degree of antibacterial action as oils obtained from A. nova. PMID:4963443

Nagy, J G; Tengerdy, R P

1967-07-01

121

Effect of sand and shaking duration on the recovery of aerobic bacteria, coliforms, and Escherichia coli from prechill broiler whole carcass rinsates.  

Technology Transfer Automated Retrieval System (TEKTRAN)

An experiment was conducted to determine the effect of added sand and shaking duration on the recovery of bacteria from broiler carcasses using the whole carcass rinse (WCR) method. In each of 4 replications, 12 eviscerated broiler carcasses were obtained from a commercial processing plant prior to ...

122

Removal of polychlorinated dioxins by semi-aerobic fed-batch composting with biostimulation of "Dehalococcoides".  

PubMed

A semi-aerobic, mesophilic, fed-batch composting (FBC) reactor loaded with household garbage was used to remove polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs). The reactor was packed with woodchips as the solid matrix and PCDD/F-contaminated soil or flyash and then operated at a waste-loading rate of 0.5 kg (wet wt) day(-1). All congeners of PCDD/Fs (initial concentration, 200-830 pmol g(-1) [dry wt]) were totally reduced during the over period of operation, with a half reduction time of 4 months. Direct cell counting and respiratory quinone profiling showed that the reactors at the fully acclimated stage harbored a high population density of bacteria (10(11) g(-1) [dry wt]) with members of the Actinobacteria predominating. Real-time quantitative PCR showed that the population of "Dehalococcoides" and its phylogenetic relatives of Chloroflexi as the possible dechlorinators varied between at the order of 10(7) to 10(8) g(-1) (dry wt). A "Dehalococcoides"-containing dechlorinating culture from the soil-treating reactor was successfully enriched with a model PCDD/F compound, fthalide. 16S rRNA gene-targeted PCR-denaturated gradient gel electrophoresis and clone library analyses showed that this culture comprised at least three major phylogenetic groups of bacteria, Acidaminobacter, "Dehalococcoides," and Rhizobium. These results suggest that the semi-aerobic FBC process is applicable for the bioremediation of PCDD/Fs and possibly other haloorganic compounds with the biostimulation of "Dehalococcoides" and its relatives as the potent dechlorinators. PMID:20159573

Narihiro, Takashi; Kaiya, Shinichi; Futamata, Hiroyuki; Hiraishi, Akira

2010-03-01

123

A molecular comparison of culturable aerobic heterotrophic bacteria and 16S rDNA clones derived from a deep subsurface sediment  

Microsoft Academic Search

Culture-based techniques have traditionally been the primary tools utilized for studying the microbiology of terrestrial subsurface environments. Recently, nucleic acid-based methods have been employed to further characterize the microbial diversity in subsurface sediments and rocks, but the results have not been related to individual bacteria cultivated from the same environment. Restriction fragment length profiles of 16S rRNA genes derived from

Darrell P Chandler; Shu-Mei Li; Christina M Spadoni; Gwendolyn R Drake; David L Balkwill; Jim K Fredrickson; Fred J Brockman

1997-01-01

124

Genotypic identification of some lactic acid bacteria by amplified fragment length polymorphism analysis and investigation of their potential usage as starter culture combinations in Beyaz cheese manufacture.  

PubMed

In this study, 2 different starter culture combinations were prepared for cheesemaking. Starter culture combinations were formed from 8 strains of lactic acid bacteria. They were identified as Lactococcus lactis ssp. lactis (2 strains), Lactobacillus plantarum (5 strains), and Lactobacillus paraplantarum (1 strain) by amplified fragment length polymorphism analysis. The effects of these combinations on the physicochemical and microbiological properties of Beyaz cheeses were investigated. These cheeses were compared with Beyaz cheeses that were produced with a commercial starter culture containing Lc. lactis ssp. lactis and Lc. lactis ssp. cremoris as control. All cheeses were ripened in brine at 4 degrees C for 90 d. Dry matter, fat in dry matter, titratable acidity, pH, salt in dry matter, total N, water-soluble N, and ripening index were determined. Sodium dodecyl sulfate-PAGE patterns of cheeses showed that alpha(S)-casein and beta-casein degraded slightly during the ripening period. Lactic acid bacteria, total mesophilic aerobic bacteria, yeast, molds, and coliforms were also counted. All analyses were repeated twice during d 7, 30, 60, and 90. The starter culture combinations were found to be significantly different from the control group in pH, salt content, and lactobacilli, lactococci, and total mesophilic aerobic bacteria counts, whereas the cheeses were similar in fat, dry matter content, and coliform, yeast, and mold counts. The sensory analysis of cheeses indicated that textural properties of control cheeses presented somewhat lower scores than those of the test groups. The panelists preferred the tastes of treatment cheeses, whereas cheeses with starter culture combinations and control cheeses had similar scores for appearance and flavor. These results indicated that both starter culture combinations are suitable for Beyaz cheese production. PMID:20059897

Karahan, A G; Ba?yi?it Kiliē, G; Kart, A; Sanlidere Alo?lu, H; Oner, Z; Aydemir, S; Erku?, O; Harsa, S

2010-01-01

125

Enumeration of Free-Living Aerobic N2-Fixing H2-Oxidizing Bacteria by Using a Heterotrophic Semisolid Medium and Most-Probable-Number Technique  

PubMed Central

A heterotrophic semisolid medium was used with two sensitive assay methods, C2H2 reduction and O2-dependent tritium uptake, to determine nitrogenase and hydrogenase activities, respectively. Organisms known to be positive for both activities showed hydrogenase activity in both the presence and absence of 1% C2H2, and thus, it was possible to test a single culture for both activities. Hydrogen uptake activity was detected for the first time in N2-fixing strains of Pseudomonas stutzeri. The method was then applied to the most-probable-number method of counting N2-fixing and H2-oxidizing bacteria in some natural systems. The numbers of H2-oxidizing diazotrophs were considerably higher in soil surrounding nodules of white beans than they were in the other systems tested. This observation is consistent with reports that the rhizosphere may be an important ecological niche for H2 transformation. PMID:16347643

Barraquio, Wilfredo L.; Dumont, Ann; Knowles, Roger

1988-01-01

126

Isolation, Characterization, and Polyaromatic Hydrocarbon Degradation Potential of Aerobic Bacteria from Marine Macrofaunal Burrow Sediments and Description of Lutibacterium anuloederans gen. nov., sp. nov., and Cycloclasticus spirillensus sp. nov.†  

PubMed Central

Two new polyaromatic hydrocarbon-degrading marine bacteria have been isolated from burrow wall sediments of benthic macrofauna by using enrichments on phenanthrene. Strain LC8 (from a polychaete) and strain M4-6 (from a mollusc) are aerobic and gram negative and require sodium chloride (>1%) for growth. Both strains can use 2- and 3-ring polycyclic aromatic hydrocarbons as their sole carbon and energy sources, but they are nutritionally versatile. Physiological and phylogenetic analyses based on 16S ribosomal DNA sequences suggest that strain M4-6 belongs to the genus Cycloclasticus and represents a new species, Cycloclasticus spirillensus sp. nov. Strain LC8 appears to represent a new genus and species, Lutibacterium anuloederans gen. nov., sp. nov., within the Sphingomonadaceae. However, when inoculated into sediment slurries with or without exogenous phenanthrene, only L. anuloederans appeared to sustain a significant phenanthrene uptake potential throughout a 35-day incubation. In addition, only L. anuloederans appeared to enhance phenanthrene degradation in heavily contaminated sediment from Little Mystic Cove, Boston Harbor, Boston, Mass. PMID:11722910

Chung, W. K.; King, G. M.

2001-01-01

127

Trends of Antibiotic Resistance in Mesophilic and Psychrotrophic Bacterial Populations during Cold Storage of Raw Milk  

PubMed Central

Psychrotrophic bacteria in raw milk are most well known for their spoilage potential and cause significant economic losses in the dairy industry. Despite their ability to produce several exoenzyme types at low temperatures, psychrotrophs that dominate the microflora at the time of spoilage are generally considered benign bacteria. It was recently reported that raw milk-spoiling Gram-negative-psychrotrophs frequently carried antibiotic resistance (AR) features. The present study evaluated AR to four antibiotics (ABs) (gentamicin, ceftazidime, levofloxacin, and trimethoprim-sulfamethoxazole) in mesophilic and psychrotrophic bacterial populations recovered from 18 raw milk samples, after four days storage at 4°C or 6°C. Robust analysis of variance and non parametric statistics (e.g., REGW and NPS) revealed that AR prevalence among psychrotrophs, for milk samples stored at 4°C, often equalled the initial levels and equalled or increased during the cold storage at 6°C, depending on the AB. The study performed at 4°C with an intermediate sampling point at day 2 suggested that (1) different psychrotrophic communities with varying AR levels dominate over time and (2) that AR (determined from relative amounts) was most prevalent, transiently, after 2-day storage in psychrotrophic or mesophilic populations, most importantly at a stage where total counts were below or around 105?CFU/mL, at levels at which the milk is acceptable for industrial dairy industrial processes. PMID:23724333

Munsch-Alatossava, Patricia; Gauchi, Jean-Pierre; Chamlagain, Bhawani; Alatossava, Tapani

2012-01-01

128

Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions  

SciTech Connect

This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

Coyne, P.; Smith, G. [New Mexico State Univ., Las Cruces, NM (United States)

1995-08-15

129

Diversity and variability of methanogens during the shift from mesophilic to thermohilic conditions while biogas production.  

PubMed

Anaerobic digestion (AD) is the most popular path of organic waste disposal. It is often used in wastewater treatment plants for excessive sludge removal. Methanogenic fermentation had usually been performed under mesophilic conditions, but in the past few years the thermophilic processes have become more popular due to economics and sludge sanitation. Methanogens, the group of microorganisms responsible for methane production, are thought to be sensitive to temperature change and it has already been proven that the communities performing methanogenesis under mesophilic and thermophilic conditions differ. But in most cases the research performed on methanogen diversity and changeability was undertaken in two separate anaerobic chambers for meso- and thermophilic conditions. It is also known that there is a group of microorganisms performing AD which are insensitive to temperature. Also the linkage between digester performance and its microbial content and community changeability is still not fully understood. That is why in this experiment we analyzed the bacterial community performing methanogenesis in a pilot scale anaerobic chamber during the shift from mesophilic to thermophilic conditions to point at the group of temperature tolerant microorganisms and their performance. The research was performed with PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis). It occurred that the community biodiversity decreased together with a temperature increase. The changes were coherent for both the total bacteria community and methanogens. These bacterial shifts were also convergent with biogas production-it decreased in the beginning of the thermophilic phase with the bacterial biodiversity decrease and increased when the community seemed to be restored. DGGE results suggest that among a wide variety of microorganisms involved in AD there is a GC-rich group relatively insensitive towards temperature change, able to adapt quickly to shifts in temperature and perform AD effectively. The studies of this microbial group could be a step forward in developing more efficient anaerobic digestion technology. PMID:25218710

Ziembi?ska-Buczy?ska, A; Banach, A; Bacza, T; Pieczykolan, M

2014-12-01

130

Ammonia oxidation kinetics determine niche separation of nitrifying Archaea and Bacteria  

E-print Network

LETTERS Ammonia oxidation kinetics determine niche separation of nitrifying Archaea and Bacteria. Stahl1 The discovery of ammonia oxidation by mesophilic and thermo- philic Crenarchaeota or their contribution to nitrification8 . Here we report oligotrophic ammonia oxidation kinetics and cellular

de la Torre, JosƩ R.

131

Reduction of Antibiotic-Resistant Bacteria Present in Food Animal Manures by Composting and Anaerobic Digestion  

E-print Network

Reduction of Antibiotic-Resistant Bacteria Present in Food Animal Manures by Composting digestion and composting at mesophilic or moderate temperature significantly reduced the antimicrobial resistance in animal manure. The most effective treatment was composting at thermophilic or high temperature

Jones, Michelle

132

Teaching Aerobic Fitness Concepts.  

ERIC Educational Resources Information Center

Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

Sander, Allan N.; Ratliffe, Tom

2002-01-01

133

Diversity, Localization, and Physiological Properties of Filamentous Microbes Belonging to Chloroflexi Subphylum I in Mesophilic and Thermophilic Methanogenic Sludge Granules  

PubMed Central

We previously reported that the thermophilic filamentous anaerobe Anaerolinea thermophila, which is the first cultured representative of subphylum I of the bacterial phylum Chloroflexi, not only was one of the predominant constituents of thermophilic sludge granules but also was a causative agent of filamentous sludge bulking in a thermophilic (55°C) upflow anaerobic sludge blanket (UASB) reactor in which high-strength organic wastewater was treated (Y. Sekiguchi, H. Takahashi, Y. Kamagata, A. Ohashi, and H. Harada, Appl. Environ. Microbiol. 67:5740-5749, 2001). To further elucidate the ecology and function of Anaerolinea-type filamentous microbes in UASB sludge granules, we surveyed the diversity, distribution, and physiological properties of Chloroflexi subphylum I microbes residing in UASB granules. Five different types of mesophilic and thermophilic UASB sludge were used to analyze the Chloroflexi subphylum I populations. 16S rRNA gene cloning-based analyses using a 16S rRNA gene-targeted Chloroflexi-specific PCR primer set revealed that all clonal sequences were affiliated with the Chloroflexi subphylum I group and that a number of different phylotypes were present in each clone library, suggesting the ubiquity and vast genetic diversity of these populations in UASB sludge granules. Subsequent fluorescence in situ hybridization (FISH) of the three different types of mesophilic sludge granules using a Chloroflexi-specific probe suggested that all probe-reactive cells had a filamentous morphology and were widely distributed within the sludge granules. The FISH observations also indicated that the Chloroflexi subphylum I bacteria were not always the predominant populations within mesophilic sludge granules, in contrast to thermophilic sludge granules. We isolated two mesophilic strains and one thermophilic strain belonging to the Chloroflexi subphylum I group. The physiological properties of these isolates suggested that these populations may contribute to the degradation of carbohydrates and other cellular components, such as amino acids, in the bioreactors. PMID:16269791

Yamada, Takeshi; Sekiguchi, Yuji; Imachi, Hiroyuki; Kamagata, Yoichi; Ohashi, Akiyoshi; Harada, Hideki

2005-01-01

134

Identification of hopanoid, sterol, and tetrahymanol production in the aerobic methanotroph Methylomicrobium alcaliphilum 20Z  

NASA Astrophysics Data System (ADS)

Correlating the occurrence of molecular biosignatures preserved in the rock record with specific microbial taxa is a compelling strategy for studying microbial life in the context of the Earth's distant past. Polycyclic triterpenoids, including the hopanes and steranes, comprise classes of biomarkers that are readily detected in a variety of ancient sediments and are clearly recognized as the diagenetic products of modern day bacterial hopanoids and eukaryotic sterols. Thus, based on the distribution of these lipids in extant microbes, the occurrence of their diagenetic products in the rock record is often utilized as evidence for the existence of specific bacterial and eukaryotic taxa in ancient ecosystems. However, questions have arisen about our understanding of the taxonomic distribution of many of these molecular biomarkers in extant microbes. This is prompting reassessments of the use of polycyclic triterpenoids as geological proxies for microbial taxa, especially in the light of the poorly defined issue of microbial diversity. Recently, significant effort has been put forth to better understand the biosynthesis, function, and regulation of these lipid molecules in a variety of modern organisms so that a more informed interpretation of their occurrence in the rock record can be reached. Here we report the unprecedented production of three different classes of polycyclic triterpenoid biomarker lipids in one bacterium. Methylomicrobium alcaliphilum 20Z, a member of the Gammaproteobacteria, is a halotolerant alkaliphilic aerobic methanotroph previously isolated from a moderately saline soda lake in Tuva (Central Asia). In this study, M. alcaliphilum is shown to produce C-3 methylated and unmethylated aminohopanoids commonly associated with other mesophilic aerobic methanotrophs. In addition, this organism is also able to produce 4,4-dimethyl sterols and surprisingly, the gammacerane triterpenoid tetrahymanol. Previously, tetrahymanol production has only been observed in freshwater and marine ciliates (such as Tetrahymena thermophila) and two bacteria unrelated to aerobic methanotrophs, Rhodopseudomonas and Bradyrhizobium. Utilizing comparative genomics we identified the oxidosqualene cyclase gene required for sterol biosynthesis as well as two copies of the squalene hopene cyclase gene necessary for hopanoid biosynthesis in the M. alcaliphilum genome. To determine if one or both copies of the squalene hopene cyclase gene were necessary for aminohopanoid or tetrahymanol production, shc gene deletions were constructed and the subsequent mutants were analyzed for impaired hopanoid production. The occurrence of sterols, hopanoids and gammacerane lipids in one bacterium not only provides a unique system in which to study the biosynthesis and function of each lipid class but also to investigate any potential functional and evolutionary relationship these three lipid classes may share. In turn, these studies provide information necessary to properly interpret the occurrence of these molecules in the rock record.

Welander, P. V.; Summons, R. E.

2013-12-01

135

Comparison of the microbial communities in solid-state anaerobic digestion (SS-AD) reactors operated at mesophilic and thermophilic temperatures.  

PubMed

The microbiomes involved in liquid anaerobic digestion process have been investigated extensively, but the microbiomes underpinning solid-state anaerobic digestion (SS-AD) are poorly understood. In this study, microbiome composition and temporal succession in batch SS-AD reactors, operated at mesophilic or thermophilic temperatures, were investigated using Illumina sequencing of 16S rRNA gene amplicons. A greater microbial richness and evenness were found in the mesophilic than in the thermophilic SS-AD reactors. Firmicutes accounted for 60 and 82 % of the total Bacteria in the mesophilic and in the thermophilic SS-AD reactors, respectively. The genus Methanothermobacter dominated the Archaea in the thermophilic SS-AD reactors, while Methanoculleus predominated in the mesophilic SS-AD reactors. Interestingly, the data suggest syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis as an important pathway for biogas production during the thermophilic SS-AD. Canonical correspondence analysis (CCA) showed that temperature was the most influential factor in shaping the microbiomes in the SS-AD reactors. Thermotogae showed strong positive correlation with operation temperature, while Fibrobacteres, Lentisphaerae, Spirochaetes, and Tenericutes were positively correlated with daily biogas yield. This study provided new insight into the microbiome that drives SS-AD process, and the findings may help advance understanding of the microbiome in SS-AD reactors and the design and operation of SS-AD systems. PMID:25194839

Li, Yueh-Fen; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Li, Yebo; Yu, Zhongtang

2015-01-01

136

Essential Oils Against Foodborne Pathogens and Spoilage Bacteria in Minced Meat  

PubMed Central

Abstract The antimicrobial activity of essential oils of oregano, thyme, basil, marjoram, lemongrass, ginger, and clove was investigated in vitro by agar dilution method and minimal inhibitory concentration (MIC) determination against Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative strains (Escherichia coli and Salmonella Enteritidis). MIC90% values were tested against bacterial strains inoculated experimentally in irradiated minced meat and against natural microbiota (aerobic or facultative, mesophilic, and psychrotrophic bacteria) found in minced meat samples. MIC90% values ranged from 0.05%v/v (lemongrass oil) to 0.46%v/v (marjoram oil) to Gram-positive bacteria and from 0.10%v/v (clove oil) to 0.56%v/v (ginger oil) to Gram-negative strains. However, the MIC90% assessed on minced meat inoculated experimentally with foodborne pathogen strains and against natural microbiota of meat did not show the same effectiveness, and 1.3 and 1.0 were the highest log CFU/g reduction values obtained against tested microorganisms. PMID:19580445

Barbosa, Lidiane Nunes; Rall, Vera Lucia Mores; Fernandes, Ana Angélica Henrique; Ushimaru, Priscila Ikeda; da Silva Probst, Isabella

2009-01-01

137

Potential of nitrogen gas (N2) to control psychrotrophs and mesophiles in raw milk.  

PubMed

Pure N(2) gas was introduced in the headspace of test bottles containing raw milk that were then stored at either 6.0, 7.0, or 12.0 degrees C. Treatment with N(2) significantly reduced the growth of total bacteria, and the growth of bacterial subgroups such as psychrotrophs, enterobacteria, protease- and lipase-producing bacteria, and Listeria spp, and completely excluded Bacillus cereus growth on MYP plates. The inhibitory effect was maximal at 6.0 degrees C, and bacterial growth could be halted at this temperature for 11 days. At 12.0 degrees C, N(2) was able to inhibit growth during the first 48 h. No alarming or undesirable effects, such as the excessive growth of anaerobes or lactobacilli, were observed during the course of the study. The same treatments also halted the growth of one bacterial isolate in pure culture that expressed multiresistance to antibiotics. The continuous flushing of raw milk with pure N(2) gas in a so-called open system that allows gas exchanges with the environment positively impacted the microbiological quality of the raw milk at a temperature range of 6.0-12.0 degrees C. This procedure should therefore be considered as a possible complementary method to refrigeration in controlling bacterial growth and the spoilage potential of both psychrotrophs and mesophiles in raw milk. PMID:19398315

Munsch-Alatossava, Patricia; Gursoy, Oguz; Alatossava, Tapani

2010-02-28

138

Resistance Versus Aerobic Exercise  

PubMed Central

OBJECTIVE In type 1 diabetes, small studies have found that resistance exercise (weight lifting) reduces HbA1c. In the current study, we examined the acute impacts of resistance exercise on glycemia during exercise and in the subsequent 24 h compared with aerobic exercise and no exercise. RESEARCH DESIGN AND METHODS Twelve physically active individuals with type 1 diabetes (HbA1c 7.1 ± 1.0%) performed 45 min of resistance exercise (three sets of seven exercises at eight repetitions maximum), 45 min of aerobic exercise (running at 60% of Vo2max), or no exercise on separate days. Plasma glucose was measured during and for 60 min after exercise. Interstitial glucose was measured by continuous glucose monitoring 24 h before, during, and 24 h after exercise. RESULTS Treatment-by-time interactions (P < 0.001) were found for changes in plasma glucose during and after exercise. Plasma glucose decreased from 8.4 ± 2.7 to 6.8 ± 2.3 mmol/L (P = 0.008) during resistance exercise and from 9.2 ± 3.4 to 5.8 ± 2.0 mmol/L (P = 0.001) during aerobic exercise. No significant changes were seen during the no-exercise control session. During recovery, glucose levels did not change significantly after resistance exercise but increased by 2.2 ± 0.6 mmol/L (P = 0.023) after aerobic exercise. Mean interstitial glucose from 4.5 to 6.0 h postexercise was significantly lower after resistance exercise versus aerobic exercise. CONCLUSIONS Resistance exercise causes less initial decline in blood glucose during the activity but is associated with more prolonged reductions in postexercise glycemia than aerobic exercise. This might account for HbA1c reductions found in studies of resistance exercise but not aerobic exercise in type 1 diabetes. PMID:23172972

Yardley, Jane E.; Kenny, Glen P.; Perkins, Bruce A.; Riddell, Michael C.; Balaa, Nadia; Malcolm, Janine; Boulay, Pierre; Khandwala, Farah; Sigal, Ronald J.

2013-01-01

139

Treatments using hot water instead of lactic acid reduce levels of aerobic bacteria and Enterobacteriaceae and reduce the prevalence of Escherichia coil O157:H7 on preevisceration beef carcasses.  

PubMed

Lactic acid has become the most commonly used organic acid for treatment of postevisceration beef carcasses. Many processors have also implemented 2% lactic acid washes on preevisceration carcasses. We previously demonstrated that hot water washing and steam vacuuming are effective carcass interventions. Because of the effectiveness of hot water, we compared its use with that of lactic acid as a preevisceration wash in a commercial setting. A commercial hot water carcass wash cabinet applying 74 degrees C (165 degrees F) water for 5.5 s reduced both aerobic plate counts and Enterobacteriaceae counts by 2.7 log CFU/100 cm2 on preevisceration carcasses. A commercial lactic acid spray cabinet that applied 2% L-lactic acid at approximately 42 degrees C (105 to 110 degrees F) to preevisceration carcasses reduced aerobic plate counts by 1.6 log CFU/100 cm2 and Enterobacteriaceae counts by 1.0 log CFU/100 cm2. When the two cabinets were in use sequentially, i.e., hot water followed by lactic acid, aerobic plate counts were reduced by 2.2 log CFU/100 cm2 and Enterobacteriaceae counts were reduced by 2.5 log CFU/100 cm2. Hot water treatments reduced Escherichia coli O157:H7 prevalence by 81%, and lactic acid treatments reduced E. coli O157:H7 prevalence by 35%, but the two treatments in combination produced a 79% reduction in E. coli O157:H7, a result that was no better than that achieved with hot water alone. These results suggest that hot water would be more beneficial than lactic acid for decontamination of preevisceration beef carcasses. PMID:16924903

Bosilevac, Joseph M; Nou, Xiangwu; Barkocy-Gallagher, Genevieve A; Arthur, Terrance M; Koohmaraie, Mohammad

2006-08-01

140

UASB performance and microbial adaptation during a transition from mesophilic to thermophilic treatment of palm oil mill effluent.  

PubMed

The treatment of palm oil mill effluent (POME) by an upflow anaerobic sludge bed (UASB) at organic loading rates (OLR) between 2.2 and 9.5 g COD l(-1) day(-1) was achieved by acclimatizing the mesophilic (37 °C) microbial seed to the thermophilic temperature (57 °C) by a series of stepwise temperature shifts. The UASB produced up to 13.2 l biogas d(-1) with methane content on an average of 76%. The COD removal efficiency ranged between 76 and 86%. Microbial diversity of granules from the UASB reactor was also investigated. The PCR-based DGGE analysis showed that the bacterial population profiles significantly changed with the temperature transition from mesophilic to thermophilic conditions. In addition, the results suggested that even though the thermophilic temperature of 57 °C was suitable for a number of hydrolytic, acidogenic and acetogenic bacteria, it may not be suitable for some Methanosaeta species acclimatized from 37 °C. Specifically, the bands associated with Methanosaeta thermophila PT and Methanosaeta harundinacea can be detected during the four consecutive operation phases of 37 °C, 42 °C, 47 °C and 52 °C, but their corresponding bands were found to fade out at 57 °C. The DGGE analysis predicted that the temperature transition can result in significant methanogenic biomass washout at 57 °C. PMID:22466006

Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn

2012-07-30

141

Reactive Blue 4 decolorization under mesophilic and thermophilic anaerobic treatments.  

PubMed

Anaerobic decolorization of anthraquinone dye represented by Reactive Blue 4 (RB4) was studied to evaluate the factors involved in dye-reducing behaviors such as dye concentration, co-substrate, treatment temperature, salt content, and dye-reducing microbial consortia. The experiment was conducted using digested sludge treated under mesophilic (35 degrees C) and thermophilic (55 degrees C) conditions. The results indicated that the thermophilic treatment gave higher potential for this dye decolorization compared with the mesophilic one. A reduced form of RB4 did not show an auto-oxidizing reaction but treated RB4 dye was shown in light yellow color, the intensity of which was related to the initial concentration of the dye used in the treatments. Starch, which showed similar decolorizing efficiency under thermophilic conditions, could be used as a co-substrate instead of glucose for the purpose of operating cost reduction. Due to the high content of salt contained in dye wastewater, the effect of salt (NaCl) was investigated. Results showed that decolorization could be accelerated with a concentration of NaCl lower than 200 mM, but the decolorization was inhibited by high concentrations of salt. The presence of RB4 inhibited methane productivity, while total organic carbon (TOC) reduction was similar to control, without dye addition. Increasing the temperature accelerated the decolorizing potential and TOC reduction. The evaluation of dye-reducing microbial consortia was done with acidogen and methanogen inhibitors which acidogenesis microorganism was dominant in RB4 decolorization. PMID:18543115

Boonyakamol, A; Imai, T; Chairattanamanokorn, P; Higuchi, T; Sekine, M; Ukita, M

2009-03-01

142

Structural differences between thermophilic and mesophilic membrane proteins  

PubMed Central

The evolutionary adaptations of thermophilic water-soluble proteins required for maintaining stability at high temperature have been extensively investigated. Little is known about the adaptations in membrane proteins, however. Here, we compare many properties of mesophilic and thermophilic membrane protein structures, including side-chain burial, packing, hydrogen bonding, transmembrane kinks, loop lengths, hydrophobicity, and other sequence features. Most of these properties are quite similar between mesophiles and thermophiles although we observe a slight increase in side-chain burial and possibly a slight decrease in the frequency of transmembrane kinks in thermophilic membrane protein structures. The most striking difference is the increased hydrophobicity of thermophilic transmembrane helices, possibly reflecting more stringent hydrophobicity requirements for membrane partitioning at high temperature. In agreement with prior work examining transmembrane sequences, we find that thermophiles have an increase in small residues (Gly, Ala, Ser, and Val) and a strong suppression of Cys. We also find a relative dearth of most strongly polar residues (Asp, Asn, Glu, Gln, and Arg). These results suggest that in thermophiles, there is significant evolutionary pressure to offload destabilizing polar amino acids, to decrease the entropy cost of side chain burial, and to eliminate thermally sensitive amino acids. PMID:23001966

Meruelo, Alejandro D; Han, Seong Kyu; Kim, Sanguk; Bowie, James U

2012-01-01

143

Hydrogen production from food waste in anaerobic mesophilic and thermophilic acidogenesis  

Microsoft Academic Search

Hydrogen production from food waste by the mesophilic and thermophilic acidogenic culture acclimated with food waste at 5 days HRT for the effect of pH and volatile solid (VS) concentrations was evaluated. The biogas produced from the thermophilic acidogenic culture was free of methane at all tested pH and VS concentrations, but methane was detected from the mesophilic acidogenic culture

Hang-Sik Shin; Jong-Ho Youn; Sang-Hyoun Kim

2004-01-01

144

Corrosion inhibition of mild steel by aerobic biofilm  

Microsoft Academic Search

Mild steel electrodes were incubated in phosphate-buffered basal salt solution (BSS) having two different aerobic bacteria, viz. Pseudomonas alcaligenes and Pseudomonas cichorii. In the medium containing P. cichorii, significant reduction in the corrosion rate was observed due to the surface reaction leading to the formation of corrosion inhibiting bacterial biofilm. With a view to understand the mechanism of microbially influenced

Shobhana Chongdar; G. Gunasekaran; Pradeep Kumar

2005-01-01

145

Aerobic and anaerobic cecal bacterial flora of commercially processed broilers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Differences in the bacterial flora of aerobic and anaerobic cultures of broiler ceca collected from a commercial poultry processing facility were determined. Bacterial isolates from cecal cultures were selected based on the ability of the bacteria to grow in media supplemented with lactate and succ...

146

Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).  

PubMed

Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086

Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

2014-07-01

147

Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester)  

PubMed Central

Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days. PMID:25026086

Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

2014-01-01

148

Micromorphology of Gram-negative hydrogen bacteria  

Microsoft Academic Search

The cell morphology, the arrangement and fine structure of flagella and the piliation of the following Gram-negative aerobic hydrogen bacteria have been studied: Alcaligenes eutrophus, Alcaligenes paradoxus, Alcaligenes ruhlandii, Pseudomonas flava, Pseudomonas pseudoflava, Pseudomonas palleronii, Pseudomonas facilis, Aquaspirillum autotrophicum, Paracoccus denitrificans, Corynebacterium autotrophicum, and strains MA 2 and SA 35. The identity of the bacteria was examined by their substrate

M. Aragno; Anna Walther-Mauruschat; F. Mayer; H. G. Schlegel

1977-01-01

149

Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io  

NASA Technical Reports Server (NTRS)

Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.

Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

2001-01-01

150

Psychrophilic and mesophilic fungi in frozen food products.  

PubMed

The mold flora of certain frozen pastries and chicken pies was investigated. Molds were determined qualitatively or quantitatively, or both, by preparing pour plates of the blended product and incubating the plates at various temperatures. The mesophilic fungal flora developed on plates incubated at 10 and 20 C, whereas psychrophilic fungi were obtained on plates incubated at 0 and 5 C. About 2,000 cultures of fungi, representing about 100 different species, were isolated from various products. Four different brands of blueberry, two brands of cherry pastries, two brands of apple, and one brand of raspberry pastries were examined. In addition, two brands of chicken pies were studied. Blueberry pastries had a much higher total fungal population than the other products, although different brands of blueberry pastries varied considerably. Blueberry pastries had from 347 to 1,586 psychrophilic fungi per g. Cherry pastries had about 70 to 110 psychrophiles per g, and apple pastries had 19 to 92 psychrophiles per g. Chicken pies contained very few psychrophilic fungi, about 15 per g. Aureobasidium pullulans was recovered most frequently. About 90% of the psychrophilic fungi found in blueberry products was A. pullulans. Depending upon the brand of cherry pastry, either Phoma spp. or A. pullulans was the most common fungus present. Apple pastries also displayed brand variation, but were unique in having many mesophilic aspergilli. This genus was generally absent from other products. The Penicillium content of apple pastries was also rather high; 50% of the psychrophilic flora was represented by this genus. The psychrophilic fungal flora of chicken pies was composed primarily of penicillia (50%) and Chrysosporium pannorum (46%). PMID:13927344

KUEHN, H H; GUNDERSON, M F

1963-07-01

151

Experimental Evolution of a Facultative Thermophile from a Mesophilic Ancestor  

PubMed Central

Experimental evolution via continuous culture is a powerful approach to the alteration of complex phenotypes, such as optimal/maximal growth temperatures. The benefit of this approach is that phenotypic selection is tied to growth rate, allowing the production of optimized strains. Herein, we demonstrate the use of a recently described long-term culture apparatus called the Evolugator for the generation of a thermophilic descendant from a mesophilic ancestor (Escherichia coli MG1655). In addition, we used whole-genome sequencing of sequentially isolated strains throughout the thermal adaptation process to characterize the evolutionary history of the resultant genotype, identifying 31 genetic alterations that may contribute to thermotolerance, although some of these mutations may be adaptive for off-target environmental parameters, such as rich medium. We undertook preliminary phenotypic analysis of mutations identified in the glpF and fabA genes. Deletion of glpF in a mesophilic wild-type background conferred significantly improved growth rates in the 43-to-48°C temperature range and altered optimal growth temperature from 37°C to 43°C. In addition, transforming our evolved thermotolerant strain (EVG1064) with a wild-type allele of glpF reduced fitness at high temperatures. On the other hand, the mutation in fabA predictably increased the degree of saturation in membrane lipids, which is a known adaptation to elevated temperature. However, transforming EVG1064 with a wild-type fabA allele had only modest effects on fitness at intermediate temperatures. The Evolugator is fully automated and demonstrates the potential to accelerate the selection for complex traits by experimental evolution and significantly decrease development time for new industrial strains. PMID:22020511

Blaby, Ian K.; Lyons, Benjamin J.; Wroclawska-Hughes, Ewa; Phillips, Grier C. F.; Pyle, Tyler P.; Chamberlin, Stephen G.; Benner, Steven A.; Lyons, Thomas J.

2012-01-01

152

Taxonomy of Aerobic Marine Eubacteria  

PubMed Central

Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are discussed. Images PMID:4552999

Baumann, Linda; Baumann, Paul; Mandel, M.; Allen, Richard D.

1972-01-01

153

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

154

Glucose-sensing proteins from mesophilic and thermophilic bacteria as new tools in diabetes monitoring  

NASA Astrophysics Data System (ADS)

We developed a new method of glucose sensing using inactive forms of glucose oxidase from Aspergillus niger and glucose dehydrogenase from the thermophilic microorganism Thermoplasma acidophilum. Glucose oxidase was rendered inactive by removal of the FAD cofactor. The resulting apo- glucose oxidase still binds glucose as observed from a decrease in its intrinsic tryptophan fluorescence. 8- Anilino-1-naphthalene sulfonic acid (ANS) was found to bind spontaneously to apo-glucose oxidase as seen from an enhancement of the ANS fluorescence. The steady state intensity of the bound ANS decreased 25% upon binding of glucose, and the mean lifetime of the bound ANS decreased about 40%. These spectral changes occurred with a midpoint from 10 to 20 mM glucose, which is comparable to the Ko of holo-glucose oxidase. These results suggest that apo- glucose oxidase can be used as a reversible non-consuming sensor for glucose.

D'Auria, S.; Rossi, Mose; Lakowicz, Joseph R.

2001-05-01

155

Antimicrobial susceptibility and extended-spectrum beta-lactamase rates in aerobic gram-negative bacteria causing intra-abdominal infections in Vietnam: report from the Study for Monitoring Antimicrobial Resistance Trends (SMART 2009-2011).  

PubMed

Treatment options for multidrug-resistant pathogens remain problematic in many regions and individual countries, warranting ongoing surveillance and analysis. Limited antimicrobial susceptibility information is available for pathogens from Vietnam. This study determined the bacterial susceptibility of aerobic gram-negative pathogens of intra-abdominal infections among patients in Vietnam during 2009-2011. A total of 905 isolates were collected from 4 medical centers in this investigation as part of the Study for Monitoring Antimicrobial Resistance Trends. Antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) rates among the appropriate species were determined by a central laboratory using Clinical and Laboratory Standards Institute methods. Among the species collected, Escherichia coli (48.1% ESBL-positive) and Klebsiella pneumoniae (39.5% ESBL-positive) represented the majority (46.4%) of the isolates submitted for this study. Ertapenem MIC90 values were lowest for these 2 species at 0.12 and 0.25?g/mL and remained unchanged for ESBL-positive isolates. Imipenem MIC90 values were also the same for all isolates and ESBL-positive strains at 0.25 and 0.5?g/mL, respectively. Ertapenem MIC90 values for additional species with sufficient numbers for analysis, including Enterobacter cloacae, Proteus mirabilis, Acinetobacter baumannii, and Pseudomonas aeruginosa, were 1, 0.06, >4, and >4?g/mL, respectively. Analysis of beta-lactamases in a subset of 132 phenotypically ESBL-positive Enterobacteriaceae demonstrated that CTX-M variants, particularly CTX-M-27 and CTX-M-15, were the predominant enzymes. High resistance rates in Vietnam hospitals dictate continuous monitoring as antimicrobial inactivating enzymes continue to spread throughout Asia and globally. PMID:24923210

Biedenbach, Douglas J; Bouchillon, Samuel K; Hoban, Daryl J; Hackel, Meredith; Phuong, Doan Mai; Nga, Tran Thi Thanh; Phuong, Nguyen Tran My; Phuong, Tran Thi Lan; Badal, Robert E

2014-08-01

156

Methylobacillus arboreus sp. nov., and Methylobacillus gramineus sp. nov., novel non-pigmented obligately methylotrophic bacteria associated with plants.  

PubMed

Two newly isolated obligate methanol-utilizing bacteria (strains Iva(T) and Lap(T)) with the ribulose monophosphate pathway of C(1) assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, motile rods multiplying by binary fission, mesophilic and neutrophilic, synthesize indole-3-acetate. The prevailing cellular fatty acids are straight-chain saturated C(16:0) and unsaturated C(16:1) acids. The major ubiquinone is Q-8. The predominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. Ammonia is assimilated by glutamate dehydrogenase. The DNA G+C contents of strains Iva(T) and Lap(T) are 54.0 and 50.5mol% (T(m)), respectively. Based on 16S rRNA gene sequence analysis and DNA-DNA relatedness (38-45%) with type strains of the genus Methylobacillus, the novel isolates are classified as the new species of this genus and named Methylobacillus arboreus Iva(T) (VKM B-2590(T), CCUG 59684(T), DSM 23628(T)) and Methylobacillus gramineus Lap(T) (VKM B-2591(T), CCUG 59687(T), DSM 23629(T)). The GenBank accession numbers for the 16S rRNA gene and mxaF gene sequences of the strains Iva(T) and Lap(T) are GU937479, GU937478 and HM030736, HM030735, respectively. PMID:21640537

Gogleva, Anna A; Kaparullina, Elena N; Doronina, Nina V; Trotsenko, Yuri A

2011-11-01

157

Psychrophilic and mesophilic fungi in fruit-filled pastries.  

PubMed

Surveys of the mold flora of frozen blueberry and cherry pastries were undertaken. Molds were enumerated by preparing pour plates of the blended product and incubating the plates at 0, 5, 10, and 20 C. In this manner, the total fungal content of the product could be ascertained from the 10 and 20 C plates, and the psychrophilic fungal population was represented by those fungi which grew at 0 and 5 C. The pastry portion, or crust, of the blueberry material was sampled separately from the filling portion. Certain differences in fungal flora were apparent. Aureobasidium pullulans was the dominant fungus in crust at all temperatures of isolation. However, Penicillium thomii proved to be the most common mesophilic fungus in the filling portion, and A. pullulans was the most common psychrophile in the filling. Aspergilli were quite common in the crust, but, in general, were absent from the fruit filling. Cherry pastries had a much smaller total fungal flora than did the blueberry product. However, A. pullulans again was the most prevalent fungus in cherry pastries at all temperatures of isolation. Certain differences in fungal flora were apparent in the two fruit products. Phoma spp. were almost completely absent in blueberries, but represented the second most common fungus in cherry pastries. Blueberry filling had 440 psychrophilic fungi per gram of sample (at 0 C), blueberry crust had 65 per gram, and cherry pastries had 77 per gram. PMID:14460237

KUEHN, H H; GUNDERSON, M F

1962-07-01

158

Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.  

PubMed

Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production. PMID:24837280

Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

2014-10-01

159

Bacterial Diversity and Sulfur Cycling in a Mesophilic Sulfide-Rich Spring  

PubMed Central

An artesian sulfide- and sulfur-rich spring in southwestern Oklahoma is shown to sustain an extremely rich and diverse microbial community. Laboratory incubations and autoradiography studies indicated that active sulfur cycling is occurring in the abundant microbial mats at Zodletone spring. Anoxygenic phototrophic bacteria oxidize sulfide to sulfate, which is reduced by sulfate-reducing bacterial populations. The microbial community at Zodletone spring was analyzed by cloning and sequencing 16S rRNA genes. A large fraction (83%) of the microbial mat clones belong to sulfur- and sulfate-reducing lineages within ?-Proteobacteria, purple sulfur ?-Proteobacteria, ?-Proteobacteria, Chloroflexi, and filamentous Cyanobacteria of the order Oscillatoria as well as a novel group within ?-Proteobacteria. The 16S clone library constructed from hydrocarbon-exposed sediments at the source of the spring had a higher diversity than the mat clone library (Shannon-Weiner index of 3.84 compared to 2.95 for the mat), with a higher percentage of clones belonging to nonphototrophic lineages (e.g., Cytophaga, Spirochaetes, Planctomycetes, Firmicutes, and Verrucomicrobiae). Many of these clones were closely related to clones retrieved from hydrocarbon-contaminated environments and anaerobic hydrocarbon-degrading enrichments. In addition, 18 of the source clones did not cluster with any of the previously described microbial divisions. These 18 clones, together with previously published or database-deposited related sequences retrieved from a wide variety of environments, could be clustered into at least four novel candidate divisions. The sulfate-reducing community at Zodletone spring was characterized by cloning and sequencing a 1.9-kb fragment of the dissimilatory sulfite reductase (DSR) gene. DSR clones belonged to the Desulfococcus-Desulfosarcina-Desulfonema group, Desulfobacter group, and Desulfovibrio group as well as to a deeply branched group in the DSR tree with no representatives from cultures. Overall, this work expands the division-level diversity of the bacterial domain and highlights the complexity of microbial communities involved in sulfur cycling in mesophilic microbial mats. PMID:12957951

Elshahed, Mostafa S.; Senko, John M.; Najar, Fares Z.; Kenton, Stephen M.; Roe, Bruce A.; Dewers, Thomas A.; Spear, John R.; Krumholz, Lee R.

2003-01-01

160

An ancient divergence among the bacteria. [methanogenic phylogeny  

NASA Technical Reports Server (NTRS)

The 16S ribosomal RNZs from two species of met methanogenic bacteria, the mesophile Methanobacterium ruminantium and the thermophile Methanobacterium thermoautotrophicum, have been characterized in terms of the oligonucleotides produced by digestion with T1 ribonuclease. These two organisms are found to be sufficiently related that they can be considered members of the same genus or family. However, they bear only slight resemblance to 'typical' Procaryotic genera; such as Escherichia, Bacillus and Anacystis. The divergence of the methanogenic bacteria from other bacteria may be the most ancient phylogenetic event yet detected - antedating considerably the divergence of the blue green algal line for example, from the main bacterial line.

Balch, W. E.; Magrum, L. J.; Fox, G. E.; Wolfe, R. S.; Woese, C. R.

1977-01-01

161

The twin arginine translocation system is essential for aerobic growth and full virulence of Burkholderia thailandensis.  

PubMed

The twin arginine translocation (Tat) system in bacteria is responsible for transporting folded proteins across the cytoplasmic membrane, and in some bacteria, Tat-exported substrates have been linked to virulence. We report here that the Tat machinery is present in Burkholderia pseudomallei, B. mallei, and B. thailandensis, and we show that the system is essential for aerobic but not anaerobic growth. Switching off of the Tat system in B. thailandensis grown anaerobically resulted in filamentous bacteria, and bacteria showed increased sensitivity to some ?-lactam antibiotics. In Galleria mellonella and zebrafish infection models, the Tat conditional mutant was attenuated. The aerobic growth-restricted phenotype indicates that Tat substrates may play a functional role in oxygen-dependent energy conservation. In other bacteria, aerobic growth restriction in Tat mutants has been attributed to the inability to translocate PetA, the Rieske iron-sulfur protein which forms part of the quinol-cytochrome c oxidoreductase complex. Here, we show that PetA is not responsible for aerobic growth restriction in B. thailandensis. However, we have identified an operon encoding 2 proteins of unknown function (BTH_I2176 and BTH_I2175) that play a role in aerobic growth restriction, and we present evidence that BTH_I2176 is Tat translocated. PMID:24214943

Wagley, Sariqa; Hemsley, Claudia; Thomas, Rachael; Moule, Madeleine G; Vanaporn, Muthita; Andreae, Clio; Robinson, Matthew; Goldman, Stan; Wren, Brendan W; Butler, Clive S; Titball, Richard W

2014-01-01

162

Exercise, Animal Aerobics, and Interpretation?  

ERIC Educational Resources Information Center

Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

Oliver, Valerie

1996-01-01

163

Aerobic granulation: advances and challenges.  

PubMed

Aerobic granulation was developed in overcoming the problem of biomass washout often encountered in activated sludge processes. The novel approach to developing fluffy biosolids into dense and compact granules offers a new dimension for wastewater treatment. Compared with conventional biological flocs, aerobic granules are characterized by well-defined shape and compact buildup, superior biomass retention, enhanced microbial functions, and resilient to toxicity and shock loading. This review provides an up-to-date account on development in aerobic granulation and its applications. Granule characterization, factors affecting granulation, and response of granules to various environmental and operating conditions are discussed. Maintaining granule of adequate structural stability is one of the main challenges for practical applications of aerobic granulation. This paper also reviews recent advances in addressing granule stability and storage for use as inoculums, and as biomass supplement to enhance treatment efficiency. Challenges and future work of aerobic granulation are also outlined. PMID:22383048

Show, Kuan-Yeow; Lee, Duu-Jong; Tay, Joo-Hwa

2012-07-01

164

Comparison of laboratory-scale thermophilic biofilm and activated sludge processes integrated with a mesophilic activated sludge process  

Microsoft Academic Search

A combined thermophilic–mesophilic wastewater treatment was studied using a laboratory-scale thermophilic activated sludge process (ASP) followed by mesophilic ASP or a thermophilic suspended carrier biofilm process (SCBP) followed by mesophilic ASP, both systems treating diluted molasses (dilution factor 1:500 corresponding GF\\/A-filtered COD (CODfilt) of 1900±190 mgl?1). With hydraulic retention times (HRTs) of 12–18 h the thermophilic ASP and thermophilic SCBP

J. Suvilampi; A. Lehtomäki; J. Rintala

2003-01-01

165

Corrosion inhibition by aerobic biofilms on SAE 1018 steel  

Microsoft Academic Search

Carbon steel (SAE 1018) samples were exposed to complex liquid media containing either the aerobic bacterium Pseudomonas fragi or the facultative anaerobe Escherichia coli DH5?. Compared to sterile controls, mass loss was consistently 2- to 10-fold lower in the presence of these bacteria which\\u000a produce a protective biofilm. Increasing the temperature from 23?C to 30?C resulted in a 2- to

A. Jayaraman; J. C. Earthman; T. K. Wood

1997-01-01

166

Aerobic microbial manufacture of nanoscale selenium: exploiting nature’s bio-nanomineralization potential  

Microsoft Academic Search

The potential of the environment to yield organisms that can produce functional bionanominerals is demonstrated by selenium-tolerant,\\u000a aerobic bacteria isolated from a seleniferous rhizosphere soil. An isolate, NS3, was identified as a Bacillus species (EU573774.1) based on morphological and 16S rRNA characterization. This strain reduced Se(IV) under aerobic conditions\\u000a to produce amorphous ? Se(0) nanospheres. A room-temperature washing treatment was

N. Tejo Prakash; Neetu Sharma; Ranjana Prakash; Kuldeep K. Raina; Jonathan Fellowes; Carolyn I. Pearce; Jonathan R. Lloyd; Richard A. D. Pattrick

2009-01-01

167

The role of autolysis of lactic acid bacteria in the ripening of cheese  

Microsoft Academic Search

The importance of autolysis of lactic acid bacteria in cheese ripening is evident from the literature. However, the mechanisms and the consequences still require investigation. The consequences of autolysis of mesophilic starters in Cheddar cheese are discussed and highlights from current physiological and genetic studies on starter autolysis are presented. The relative merits of measuring starter autolysis in cheese by

V. L. Crow; T. Coolbear; P. K. Gopal; F. G. Martley; L. L. McKay; H. Riepe

1995-01-01

168

The detrital food chain based on seaweeds. I. Bacteria associated with the surface of Laminaria fronds  

Microsoft Academic Search

The bacteria associated with the surface of fronds of the sublittoral brown alga Laminaria longicruris were investigated over a 13-month period on the coast of Nova Scotia (Canada). A psychrophilic population was found to be associated with the frond during the winter and a mesophilic population with the decaying frond during the summer. Numbers of psychrophiles varied inversely with ambient

R. A. Laycock

1974-01-01

169

[The aerobic air microflora in airplanes on various international routes].  

PubMed

Aerobic microflora (bacteria, fungi), in the cock pits of the TAROM company (Boeing 707 and Il 62 M) airships flying on various international routes and airports was studied during November 1988-January 1989. 157-8,800 bacteria and 78-1,336 fungi per m3 air were recorded. Except for Staphylococcus aureus (hemolytic and non hemolytic) the greatest part of the isolated microorganisms was nonpathogenic for man: Bacillus, Corynebacterium, Neisseria, Staphylococcus epidermidis, Sarcina, Aspergillus, Penicillium etc. Several airships on the Asian airports contained a higher amount of bacteria and fungi but not higher than in the living rooms. Likewise, in high altitude flights, the microorganism amount was less than on the ground. The taxonomic spectrum of the bacteria and fungi isolated was almost identical on all the 9 international airports, thus suggesting the homogeneous and international character of saprophyte and pathogenic air microflora by means of the passenger and goods air flights. PMID:2616999

N?stoiu, I; R?duic?, C; Soitu, V; Gavril?, I

1989-01-01

170

Ribosomes, polyribosomes, and deoxyribonucleic acid from thermophilic mesophilic, and psychrophilic clostridia.  

PubMed

Analysis of deoxyribonucleic acid (DNA) from four species of Clostridium, including two thermophiles, a mesophile, and a psychrophile, revealed no obvious relationship between growth temperature and DNA base composition. The melting temperatures (T(m)) of the DNA from the four species varied no more among the thermophilic, mesophilic, and psychrophilic species than among many related mesophilic species. Characterization of ribosomes from the clostridia by means of optical rotatory dispersion yielded similar spectra in common with other unrelated organisms. Only small differences were noted in the base composition of ribosomal ribonucleic acid (RNA) and in the amino acid composition of ribosomal proteins, including half-cystine content, as determined by cysteic acid analysis, and accessible sulfhydryl groups, as determined by titration with dithiobis (2-nitrobenzoic acid). Except for the two thermophiles, the ribosomal protein electrophoretic patterns were dissimilar. No unusual thermal stability was manifested in the T(m) values of thermophile ribosomal RNA. However, thermophile ribosome T(m) values (69 C) were higher than were mesophile and psychrophile T(m) values (64 C). Ribosomes from the four clostridial species were also examined in regard to the effect of heat on their functional integrity, measured by their activity in poly U-directed (14)C-phenylaline incorporation, and their gross physical integrity, measured by sucrose gradient analysis. The T(d, 5) values (temperature which produces 50% inactivation after 5 min) was found to be 70 and 72 C for the two thermophiles C. tartarivorum and C. thermosaccharolyticum, respectively; 57 C for a mesophile, C. pasteurianum; and 53 C for a psychrophile, Clostridium sp. strain 69. At 55 C, little effect was seen on the thermophile ribosomes, but the mesophile ribosomes lost 90% of their activity in 1 hr, and psychrophile ribosomes lost 100% of their activity within 10 min. According to sucrose gradient profiles, heating at 55 C results in dissociation of mesophile ribosomes and aggregation of psychrophile ribosomes. Thermophile S-100 fractions were also more thermostable than were mesophile or psychrophile S-100 fractions. The T(d, 5) values were 69 C for C. tartarivorum and C. thermosaccharolyticum S-100 and 41 C for C. pasteurianum and Clostridium sp. strain 69 S-100. The effect of heat on the endogenous incorporation of (14)C-valine by polysomes was also examined. In the case of thermophile polysomes, the extent of incorporation at 55 and 37 C was about equal. In the case of mesophile and psychrophile polysomes, the extent at 55 C was 44 and 39%, respectively, of the value at 37 C. The initial rates of incorporation in all four cases were greater at 55 C than at 37 C. PMID:4688140

Irwin, C C; Akagi, J M; Himes, R H

1973-01-01

171

Fermentation of Wood-dust by Cellulose Bacteria  

Microsoft Academic Search

IN this laboratory, fermentation of birch, aspen and pine-dusts has been investigated by enrichment cultures of thermophilic1, and recently also of mesophilic2, cellulose bacteria. he Tfiner the wood was ground, the more of the cellulose was fermented. In the best cases, a fermentation of about 70 per cent of cellulose in wood was obtained with the leaf-tree dust at 60°

Artturi I. Virtanen

1946-01-01

172

Aerobic granular sludge: recent advances.  

PubMed

Aerobic granulation, a novel environmental biotechnological process, was increasingly drawing interest of researchers engaging in work in the area of biological wastewater treatment. Developed about one decade ago, it was exciting research work that explored beyond the limits of aerobic wastewater treatment such as treatment of high strength organic wastewaters, bioremediation of toxic aromatic pollutants including phenol, toluene, pyridine and textile dyes, removal of nitrogen, phosphate, sulphate and nuclear waste and adsorption of heavy metals. Despite this intensive research the mechanisms responsible for aerobic granulation and the strategy to expedite the formation of granular sludge, and effects of different operational and environmental factors have not yet been clearly described. This paper provides an up-to-date review on recent research development in aerobic biogranulation technology and applications in treating toxic industrial and municipal wastewaters. Factors affecting granulation, granule characterization, granulation hypotheses, effects of different operational parameters on aerobic granulation, response of aerobic granules to different environmental conditions, their applications in bioremediations, and possible future trends were delineated. The review attempts to shed light on the fundamental understanding in aerobic granulation by newly employed confocal laser scanning microscopic techniques and microscopic observations of granules. PMID:18573633

Adav, Sunil S; Lee, Duu-Jong; Show, Kuan-Yeow; Tay, Joo-Hwa

2008-01-01

173

Treatment of phenolics, aromatic hydrocarbons, and cyanide-bearing wastewater in individual and combined anaerobic, aerobic, and anoxic bioreactors.  

PubMed

Studies were conducted on a mixture of pollutants commonly found in coke oven wastewater (CWW) to evaluate the biodegradation of various pollutants under anaerobic, aerobic, and anoxic conditions. The removal of the pollutants was monitored during individual bioreactor operation and using a combination of bioreactors operating in anaerobic-aerobic-anoxic sequence. While studying the performance of individual reactors, it was observed that cyanide removal (83.3 %) was predominant in the aerobic bioreactor, while much of the chemical oxygen demand (COD) (69 %) was consumed in the anoxic bioreactor. With the addition of cyanide, the COD removal efficiency was affected in all the bioreactors, and several intermediates were detected. While treating synthetic CWW using the combined bioreactor system, the overall COD removal efficiency was 86.79 % at an OLR of 2.4 g COD/L/day and an HRT of 96 h. The removal efficiency of 3,5-xylenol and cyanide, with inlet concentration of 150 and 10 mg/L, was found to be 91.8 and 93.6 % respectively. It was found that the impact of xylenol on the performance of the bioreactors was less than cyanide toxicity. Molecular analysis using T-RFLP revealed the dominance of strictly aerobic, mesophilic proteobacterium, Bosea minatitlanensis, in the aerobic bioreactor. The anoxic bioreactor was dominant with Rhodococcus pyridinivorans, known for its remarkable aromatic decomposing activity, while an unclassified Myxococcales bacterium was identified as the predominant bacterial species in the anaerobic bioreactor. PMID:25267355

Sharma, Naresh K; Philip, Ligy

2015-01-01

174

Comparison of mesophilic and thermophilic anaerobic digestion of sugar beet pulp: performance, dewaterability and foam control.  

PubMed

Digestion of sugar beet pulp was assessed in relation to biogas and methane production, foaming potential, and digestate dewaterability. Four 4-litre working volume digesters were operated mesophilically (37±0.5 °C) and four thermophilically (55±0.5 °C) over three hydraulic retention times. Digesters were operated in duplicate at organic loading rates (OLR) of 4 and 5 g volatile solids l(-1) day(-1) without water addition. Thermophilic digestion gave higher biogas and methane productivity than mesophilic and was able to operate at the higher OLR, where mesophilic digestion showed signs of instability. Digestate dewaterability was assessed using capillary suction time and frozen image centrifugation. The occurrence of, or potential for, stable foam formation was assessed using a foaming potential test. Thermophilic operation allowed higher loadings to be applied without loss of performance, and gave a digestate with superior dewatering characteristics and very little foaming potential. PMID:24291796

Suhartini, Sri; Heaven, Sonia; Banks, Charles J

2014-01-01

175

Effect of high temperature on bacterial community dynamics in anaerobic acidogenesis using mesophilic sludge inoculum.  

PubMed

In this study, we investigated the microbial community dynamics in thermal acidogenesis using mesophilic sludge. From the result of optimization with a response surface methodology, the acidogenic optimum conditions predicted were a hydraulic retention time of 2.0 days and 51 degrees C. Denaturing gradient gel electrophoresis (DGGE) profiles shows that the monitored bacterial community present consists of Pseudomonas mendocina, Bacillus halodurans, Clostridium hastiforme, Gracilibacter thermotolerans, and Thermomonas haemolytica. Among these, B. halodurans, G. thermotolerans, and T. haemolytica are reported to ferment carbohydrates thermotolerantly. In contrast, P. mendocina disappeared in the acidogenesis process because of its mesophilicity. In addition, C. hastiforme, G. thermotolerans originating from mesophilic anaerobic sludge were detected in the thermal acidogenesis. Based on this finding, we inferred that most thermophiles detected as DGGE bands could grow catalyzing carbohydrates metabolism in swine wastewater to produce volatile fatty acids thermotolerantly. PMID:19362824

Kim, Woong; Hwang, Kwanghyun; Shin, Seung Gu; Lee, Seungyong; Hwang, Seokhwan

2010-01-01

176

Clinical microbiology of coryneform bacteria.  

PubMed Central

Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed. PMID:8993861

Funke, G; von Graevenitz, A; Clarridge, J E; Bernard, K A

1997-01-01

177

Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor  

NASA Technical Reports Server (NTRS)

Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

1995-01-01

178

Differentiation of Methanosaeta concilii and Methanosarcina barkeri in Anaerobic Mesophilic Granular Sludge by Fluorescent In Situ Hybridization and Confocal Scanning Laser Microscopy†  

PubMed Central

Oligonucleotide probes, designed from genes coding for 16S rRNA, were developed to differentiate Methanosaeta concilii, Methanosarcina barkeri, and mesophilic methanogens. All M. concilii oligonucleotide probes (designated MS1, MS2, and MS5) hybridized specifically with the target DNA, but MS5 was the most specific M. concilii oligonucleotide probe. Methanosarcina barkeri oligonucleotide probes (designated MB1, MB3, and MB4) hybridized with different Methanosarcina species. The MB4 probe specifically detected Methanosarcina barkeri, and the MB3 probe detected the presence of all mesophilic Methanosarcina species. These new oligonucleotide probes facilitated the identification, localization, and quantification of the specific relative abundance of M. concilii and Methanosarcina barkeri, which play important roles in methanogenesis. The combined use of fluorescent in situ hybridization with confocal scanning laser microscopy demonstrated that anaerobic granule topography depends on granule origin and feeding. Protein-fed granules showed no layered structure with a random distribution of M. concilii. In contrast, a layered structure developed in methanol-enriched granules, where M. barkeri growth was induced in an outer layer. This outer layer was followed by a layer composed of M. concilii, with an inner core of M. concilii and other bacteria. PMID:10224023

Rocheleau, Sylvie; Greer, Charles W.; Lawrence, John R.; Cantin, Christiane; Laramée, Louise; Guiot, Serge R.

1999-01-01

179

Use of mild irradiation doses to control pathogenic bacteria on meat trimmings for production of patties aiming at provoking minimal changes in quality attributes.  

PubMed

The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5 kGy) and to reduce the risk of pathogen presence without altering the quality attributes of bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ?2.5 kGy are used, reductions of 2 log CFU/g of L. monocytogenes and 5 log CFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high. PMID:25042241

Xavier, Ma de la Paz; Dauber, Cecilia; Mussio, Paula; Delgado, Enrique; Maquieira, Ana; Soria, Alejandra; Curuchet, Ana; Mįrquez, Rosa; Méndez, Carlos; López, Tomįs

2014-11-01

180

Aerobic and anaerobic microorganisms in tubercles of the Columbus, Ohio, water distribution system.  

PubMed Central

Aerobic and anaerobic microorganisms were enumerated in tubercles collected from sections of the water distribution pipeline in the Columbus, Ohio, metropolitan area. Coliform bacteria were not detected in the tubercles examined. Sulfate-reducing bacteria were detected in 80% of the samples. Nitrate-reducing heterotrophs were present in all samples. The results, including plate counts of aerobic heterotrophs, indicated variation in bacterial densities depending on the tubercle sample and fraction examined. The associations among the viable counts obtained by the different culture methods were analyzed statistically, using three methods (Pearson, Spearman, and Kendall). PMID:7138010

Tuovinen, O H; Hsu, J C

1982-01-01

181

Enhancement of microbial quality and inactivation of pathogenic bacteria by gamma irradiation of ready-to-cook Iranian barbecued chicken  

NASA Astrophysics Data System (ADS)

Ready-to-cook Iranian barbecued chicken consists of cubed chicken breast, lemon juice, salt, red pepper, onion, saffron and vegetable oil with an overall pH value of about 5.5. This product is sometimes consumed under-cooked, hence it may pose health hazards to consumers when contaminated with food-borne pathogens. In this study, the effect of gamma irradiation (0, 1.5, 3 and 4.5 kGy) on the microbial quality of ready-to-cook (RTC) barbecued chicken samples stored at 4 °C for 15 days was investigated. Moreover, the effectiveness of irradiation for inactivating Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella typhimurium inoculated into the samples was also studied. Irradiation of the samples resulted in dose dependent reduction in counts of aerobic mesophilic bacteria, yeasts and molds, Enterobacteriaceae and lactic acid bacteria. Among the microbial flora, yeasts and molds and Enterobacteriaceae were more sensitive to irradiation and got completely eliminated at dose of 3 kGy. D10 values of L. monocytogenes, E. coli O157:H7 and S. typhimurium inoculated into the samples were 0.680, 0.397 and 0.601 kGy, respectively. An irradiation dose of 3 kGy reduced the counts of E. coli O157:H7 to an undetectable level in RTC barbecued chicken but was ineffective on elimination of L. monocytogenes and S. typhimurium. However, none of the food-borne pathogens were detected in the samples irradiated at 4.5 kGy. This study showed that irradiation had no undesirable effects on the initial sensory attributes of barbecued chicken. At the end of the storage period, irradiated samples were more acceptable compared to non-irradiated ones.

Fallah, Aziz A.; Siavash Saei-Dehkordi, S.; Rahnama, Mohammad

2010-10-01

182

Petroleum hydrocarbon-degrading bacteria in the Galveston Bay system  

E-print Network

Dr. E. T. Park A seasonal survey of aerobic heterotrophic and petro- leum hydrocarbon-degrading bacterial populations of the Galveston Bay system was conducted. Aerobic hetrotrophic bacteria ranged from 1. 82 x 10 to 3. 32 x 10 CFU/ml 2 5 water... environmental parameters. Hydrocarbon-degrading bacteria were found in all parts of the bay system. The total number of hydrocarbon-degrading bacteria ranged from less than 3. 0 to 9. 25 x 102/ml water and from less than 3. 0 x 1. 10 to 1. 10 x 10 /ml wet...

Schropp, Steven James

2012-06-07

183

Effect of Increasing Total Solids Contents on Anaerobic Digestion of Food Waste under Mesophilic Conditions: Performance and Microbial Characteristics Analysis  

PubMed Central

The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies. PMID:25051352

Jin, Jingwei; Dai, Xiaohu

2014-01-01

184

Exopolysaccharide-producing mesophilic lactic cultures for preparation of fat-free Dahi - an Indian fermented milk.  

PubMed

Forty seven exopolysaccharide (EPS) producing mesophilic lactic acid bacteria have been isolated from Dahi and raw milk and selected cultures were evaluated for their influence on rheological and sensory properties of fat-free Dahi. Two isolates namely B-6 and KT-24 that showed promising technological attributes were identified as Lc. lactis subsp. lactis strains. B-6 produced 184+/-2 mg/l EPS in deproteinized whey medium compared with 193+/-1 mg/l by KT-24. EPS produced by B-6 was a heteropolysaccharide (consisting of glucose and mannose, 1:7 x 4) with molecular weight of 3.0x104 Da whereas KT-24 EPS was a homopolysaccharide (rhamnose) having molecular weight of 4.5x104 Da. Both EPS producing cultures showed significant changes in rheological and sensory properties of fat-free Dahi. Dahi prepared by these cultures was more viscous, adhesive, sticky, showed lower susceptibility to whey separation, and received higher sensory scores than Dahi prepared with non-EPS producing culture. PMID:19121242

Behare, Pradip; Singh, Rameshwar; Singh, Rudrapratap P

2009-02-01

185

Bacteria Museum  

NSDL National Science Digital Library

Who knew that bacteria had their own virtual museum? Here, visitors will "learn that not all bacteria are harmful, how they are used in industry, that they belong to the oldest living creatures on Earth", and many more interesting facts to discover about the diverse world of bacteria. The "Bacterial Species Files" tab at the top of the page, allows visitors to look up information on 40 different specific bacteria, from Anthrax to Yersinia enterocolitica. The information provided for each bacterium includes photographs, consumer guides, fact sheets, and scientific links. Visitors will find that the "Main Exhibits" tab addresses the basics about bacteria, as well as "Pathogenic Bacteria", "Evolution", "How We Fight Bacteria", and "Food and Water Safety". Visitors will surely enjoy the "Good Bacteria in Food" link found in the Food and Water Safety section, as it explains how some foods benefit from good bacteria, such as Swiss cheese, sausage, sauerkraut, chocolate, and coffee.

186

Complete Genome Sequence of the Subsurface, Mesophilic Sulfate-Reducing Bacterium Desulfovibrio aespoeensis Aspo-2  

PubMed Central

Desulfovibrio aespoeensis Aspo-2, DSM 10631T, is a mesophilic, hydrogenotrophic sulfate-reducing bacterium sampled from a 600-m-deep subsurface aquifer in hard rock under the island of Äspö in southeastern Sweden. We report the genome sequence of this bacterium, which is a 3,629,109-bp chromosome; plasmids were not found. PMID:24874683

Bengtsson, Andreas; Edlund, Johanna; Rabe, Lisa; Hazen, Terry; Chakraborty, Romy; Goodwin, Lynne; Shapiro, Nicole

2014-01-01

187

Mesophilic biogas production from fruit and vegetable waste in a tubular digester  

Microsoft Academic Search

A semi-continuously mixed mesophilic tubular anaerobic digester was tested for the conversion of fruit and vegetable waste (FVW) into biogas. The effect of hydraulic retention time (HRT) and the feed concentration on the extent of the degradation of the waste was examined. Varying the HRT between 12 and 20 days had no effect on the fermentation stability and pH remained

H Bouallagui; R Ben Cheikh; L Marouani; M Hamdi

2003-01-01

188

[The comparative characteristics of the antibiotic sensitivity of psychrophilic and mesophilic aeromonads].  

PubMed

The general regularities of the antibiotic susceptibility of psychrophilic and mesophilic aeromonads were determined. The antibioticograms were in general similar. Still, there was observed a higher susceptibility of Aeromonas salmonicida to tetracycline, chloramphenicol and rifampicin, as well as a larger number of strains susceptible to semisynthetic broad spectrum penicillins (ampicillin and carbenicillin) and cephazoline. The susceptibility to aminoglycosides was lower. PMID:8085887

Shenderovich, V A; Gorelov, A L; Stoliarova, L G; Vlasova, I V; Solov'eva, V E; Kha?tovich, A B

1993-01-01

189

COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC DIGESTION - PHASE II. STEADY STATE STUDIES  

EPA Science Inventory

A study of the relative performance of anaerobic digestion systems under mesophilic and thermophilic conditions was conducted. Fifty liter laboratory scale digesters were fed primary sludge from the Allentown, PA Waste Water Treatment Plant. Long-term, steady-state performance da...

190

COMPARATIVE EVALUATION OF MESOPHILIC AND THERMOPHILIC ANAEROBIC DIGESTION. PHASE 2. STEADY STATE STUDIES  

EPA Science Inventory

A study was conducted of the relative performance of anaerobic digestion systems under mesophilic and thermophilic conditions. Fifty liter laboratory scale digesters were fed primary sludge from the Allentown, PA Waste Water Treatment Plant. Long-term, steady-state performance da...

191

Kinetic characterization of thermophilic and mesophilic anaerobic digestion for coffee grounds and waste activated sludge.  

PubMed

This study was conducted to characterize the kinetics of an anaerobic process (hydrolysis, acetogenesis, acidogenesis and methanogenesis) under thermophilic (55°C) and mesophilic (35°C) conditions with coffee grounds and waste activated sludge (WAS) as the substrates. Special focus was given to the kinetics of propionic acid degradation to elucidate the accumulation of VFAs. Under the thermophilic condition, the methane production rate of all substrates (WAS, ground coffee and raw coffee) was about 1.5times higher than that under the mesophilic condition. However, the effects on methane production of each substrate under the thermophilic condition differed: WAS increased by 35.8-48.2%, raw coffee decreased by 76.3-64.5% and ground coffee decreased by 74.0-57.9%. Based on the maximum reaction rate (Rmax) of each anaerobic stage obtained from the modified Gompertz model, acetogenesis was found to be the rate-limiting step for coffee grounds and WAS. This can be explained by the kinetics of propionate degradation under thermophilic condition in which a long lag-phase (more than 18days) was observed, although the propionate concentration was only 500mg/L. Under the mesophilic condition, acidogenesis and hydrolysis were found to be the rate-limiting step for coffee grounds and WAS, respectively. Even though reducing the particle size accelerated the methane production rate of coffee grounds, but did not change the rate-limiting step: acetogenesis in thermophilic and acidogenesis in mesophilic. PMID:25534040

Li, Qian; Qiao, Wei; Wang, Xiaochang; Takayanagi, Kazuyuki; Shofie, Mohammad; Li, Yu-You

2015-02-01

192

Occurrence and antibiotic resistance of mesophilic Aeromonas in three riverine freshwaters of Marrakech, Morocco.  

PubMed

In order to evaluate the impact of pollution and sewage on the occurrence and antibiotic resistance of mesophilic aeromonads in riverine freshwaters of Marrakech, samples were collected from three rivers (Oukaimeden, Ourika, and Tensift) upstream and downstream from the principal bordering villages. During a 2-year study, indicators of pollution increased dramatically in the downstream waters. Bacterial indicators (faecal coliforms and faecal streptococci) correlated with mesophilic aeromonads only in heavily polluted waters. In low and moderately polluted sources, densities of mesophilic aeromonads were independent of water quality indicators and did not correlate statistically with faecal indicators. Average counts of Aeromonas in low and heavily polluted waters were 2.5 x 10(3) and 2.1 x 10(6) colony forming units per 100 ml, respectively. The biochemical identification of 841 isolates indicated a predominance of A. caviae in heavily and moderately polluted water and sediment. A. hydrophila was dominant only in low polluted waters and when the temperature was below 12 degrees C. High densities of A. sobria were found in low, moderately polluted, or cleaned waters and when the water temperature was above 18 degrees C. All selected isolates (total = 841) were tested for antibiotic susceptibility against 21 antibiotics. Antibiotic resistance frequencies recorded were: ampicillin and amoxicillin, 100%; novobiocin, 96%; cefalotin, 81%; colistin, 72%; sulfamethoxazole, 40%; cefamandole, 37%; polymyxin B, 23%; trimethoprim, 17%; erythromycin, 15%; streptomycin, 8%; amoxicillin-clavulanate, 5%. Resistance to cefotaxime, kanamycin, gentamycin, chloramphenicol, tetracycline, oxytetracycline, nalidixic acid, rifampicin, or trimethoprim-sulfameth-oxazole was found to be <5%. Antibiotic resistance rates did vary according to the source of a strain"s isolation, and high numbers of antibiotic resistant strains were recorded in polluted samples. Since no correlation between mesophilic aeromonads and conventional faecal pollution indicators was observed in low or moderately polluted waters, and since these freshwaters are used for domestic supply, we propose the use of mesophilic aeromonads as complementary water pollution indicators to ensure the safety of water. PMID:12805714

Imziln, B

2001-12-01

193

Molecular interactions within the halophilic, thermophilic, and mesophilic prokaryotic ribosomal complexes: clues to environmental adaptation.  

PubMed

Using the available crystal structures of 50S ribosomal subunits from three prokaryotic species: Escherichia coli (mesophilic), Thermus thermophilus (thermophilic), and Haloarcula marismortui (halophilic), we have analyzed different structural features of ribosomal RNAs (rRNAs), proteins, and of their interfaces. We have correlated these structural features with the environmental adaptation strategies of the corresponding species. While dense intra-rRNA packing is observed in thermophilic, loose intra-rRNA packing is observed in halophilic (both compared to mesophilic). Interestingly, protein-rRNA interfaces of both the extremophiles are densely packed compared to that of the mesophilic. The intersubunit bridge regions are almost devoid of cavities, probably ensuring the proper formation of each bridge (by not allowing any loosely packed region nearby). During rRNA binding, the ribosomal proteins experience some structural transitions. Here, we have analyzed the intrinsically disordered and ordered regions of the ribosomal proteins, which are subjected to such transitions. The intrinsically disordered and disorder-to-order transition sites of the thermophilic and mesophilic ribosomal proteins are simultaneously (i) highly conserved and (ii) slowly evolving compared to rest of the protein structure. Although high conservation is observed at such sites of halophilic ribosomal proteins, but slow rate of evolution is absent. Such differences between thermophilic, mesophilic, and halophilic can be explained from their environmental adaptation strategy. Interestingly, a universal biophysical principle evident by a linear relationship between the free energy of interface formation, interface area, and structural changes of r-proteins during assembly is always maintained, irrespective of the environmental conditions. PMID:24697502

Mallik, Saurav; Kundu, Sudip

2015-03-01

194

Growth of aerobic bacteria on alkali-solubilized lignite  

SciTech Connect

Coal contains a complex mixture of organic compounds, the variety of which depends on the particular type of coal. There is a general agreement that coal is composed of a macromolecular fraction and a lower-mol-wt fraction that are noncovalently associated with each other. Huttinger and Michenfelder have proposed a structural unit for the macromolecular portion of a lignite coal that comprises 2 and 3-ring fused aromatics, paraffin, terpene, cycloaliphatics, hydrocarbon bridges, several carboxyl moieties, straight-chain saturated hydrocarbons, branched-chain hydrocarbons, sulfur heterocyclics, ether linkages, alcohol groups, nitrogen heterocyclics, and chelated metals. Low-mol-wt compounds found in coal can be separated from macromolecules by extraction with organic solvents, such as tetrahydrofuran. Low-mol-wt organic compounds that have been revealed by such extractions include straight-chain (C{sub 13}-C{sub 33}), branched, and cyclic alkanes; aryl and aryl alkyl compounds with 1-6 rings; and phenolic compounds. In low-ranked coals, branched alkanes predominate over straight chain. This report describes the enrichment for, and isolation of, microorganisms that are capable of modifying lignite.

Polman, J.K.; Breckenridge, C.R.; Dugan, P.R.; Quigley, D.R. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1991-12-31

195

Cellulose synthesized by Enterobacter sp. FY-07 under aerobic and anaerobic conditions.  

PubMed

Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. In static cultivation at 30 °C for 72 h under anoxic, oxygen-limited and aerated conditions, cellulose production exceeded 5 g/l, which indicated that oxygen was not essential for production of BC by Enterobacter sp. FY-07. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis showed that the microstructure of the BC was similar to that produced by aerobic bacteria such as Gluconacetobacter xylinum BCRC12335 and Acetobacter sp. V6. The crystallinity index of the BC was 63.3%. Water-holding capacity (approximately 11000%) and rehydration ratio (24.4%) were superior to those reported for BC produced by the aerobic bacteria G. xylinum BCRC12335 and Acetobacter sp. V6. These results will facilitate static submerged fermentation for the production of BC. PMID:23073085

Ma, Ting; Ji, Kaihua; Wang, Wei; Wang, Jinghong; Li, Zhaoyu; Ran, Haitao; Liu, Bin; Li, Guoqiang

2012-12-01

196

Comparative investigation on microbial community and electricity generation in aerobic and anaerobic enriched MFCs.  

PubMed

This study compared the difference in microbial community and power generation capacity of air-cathode MFCs enriched under anode aerobic and anaerobic conditions. Results showed that MFCs successfully started with continuous air inputting to anode chamber. The aerobic enriched MFC produced comparable and even more electricity with the fuels of acetate, glucose and ethanol compared to the anaerobic MFC when returning to anaerobic condition. The two MFCs showed a slightly different microbial community for anode biofilms (a similarity of 77%), but a highly similar microbial community (a similarity of 97%) for anolyte microbes. The anode biofilm of aerobic enriched MFC showed the presence of some specific bacteria closely related to Clostridium sticklandii, Leucobacter komagatae and Microbacterium laevaniformans. The anaerobic enriched MFC found the presence of a large number of yeast Trichosporon sp. This research demonstrates that it is possible to enrich oxygen-tolerant anode respiring bacteria through purposely aeration in anode chamber. PMID:23196248

Quan, Xiang-chun; Quan, Yan-ping; Tao, Kun; Jiang, Xiao-man

2013-01-01

197

Aerobic granulation in a sequencing batch reactor for the treatment of piggery wastewater.  

PubMed

This study investigated the formation of aerobic granules fed with digested piggery wastewater. After 42 days of cultivation, small yellow granules with mean diameter of 0.4 mm were first observed in the reactor. Scanning electron microscope pictures showed the granules were compact, round structures with clear outer shapes and mainly composed of filamentous bacteria. Maximum chemical oxygen demand and ammonia removal ratios were 90.1 and 91.7%, respectively. The Monod equation, which was used to describe ammonium utilization, yielded a maximum rate of 6.25 mg (g volatile suspended solids)(-1) h(-1). The measurement of extracellular polymeric substances (EPS) content and three-dimensional excitation and emission matrix results showed that the EPS concentration increased during the granulation process. Fluorescence in situ hybridization analysis showed significant amounts of nitrifying bacteria in the aerobic granules. Results in this study provide insights to the treatment of piggery wastewater using aerobic granular sludge. PMID:23581239

Zhang, Dalei; Wang, Yanan; Li, Hongwei; Wang, Shaoran; Jing, Yumei

2013-03-01

198

Onsite Wastewater Treatment Systems: Aerobic Treatment Unit  

E-print Network

. Onsite wastewater treatment systems Single-compartment trash tank Chlorinator Aerobic treatment unit Spray heads Pump tank Bruce Lesikar Professor and Extension Agricultural Engineer The Texas A&M System Aerobic treatment units, which are certified...

Lesikar, Bruce J.

2008-10-31

199

Identification of tandemly repeated type VI cellulose-binding domains in an endoglucanase from the aerobic soil bacterium Cellvibrio mixtus  

Microsoft Academic Search

Cellulose-binding domains (CBD) play a pivotal role during plant cell wall hydrolysis by cellulases and xylanases from aerobic\\u000a soil bacteria. Recently we?have reported the molecular characterisation of a single-domain endoglucanase from Cellvibrio mixtus, suggesting that some cellulases produced by this aerobic bacterium preferentially hydrolyse soluble cellulosic substrates.\\u000a Here we describe the complete nucleotide sequence of a second cellulase gene, celB,

C. M. G. A. Fontes; J. H. Clarke; G. P. Hazlewood; T. H. Fernandes; H. J. Gilbert; L. M. A. Ferreira

1998-01-01

200

Species Diversity and Substrate Utilization Patterns of Thermophilic Bacterial Communities in Hot Aerobic Poultry and Cattle Manure Composts  

Microsoft Academic Search

This study investigated the species diversity and substrate utilization patterns of culturable thermophilic bacterial communities\\u000a in hot aerobic poultry and cattle manure composts by coupling 16S rDNA analysis with Biolog data. Based on the phylogenetic\\u000a relationships of 16S rDNA sequences, 34 thermophilic (grown at 60°C) bacteria isolated during aerobic composting of poultry\\u000a manure and cattle manure were classified as Bacillus

Chao-Min Wang; Ching-Lin Shyu; Shu-Peng Ho; Shiow-Her Chiou

2007-01-01

201

Arthritis and Aerobic Exercise: A Review.  

ERIC Educational Resources Information Center

Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

Ike, Robert W.; And Others

1989-01-01

202

Radiosensitivity of subterranean bacteria in the Hungarian upper permian siltstone formation  

Microsoft Academic Search

The main purpose of this work was to study the radioresistance of subterranean aerobic and anaerobic isolates from the Hungarian Upper Permian Siltstone (Aleurolite) Formation, in order to assess the safety of potential sites of future underground repositories for nuclear waste. A total of 93 isolates were studied. The radiosensitivities of these aerobic and anaerobic bacteria isolates were determined: the

Gyöngyi Farkas; L. G. Gazsó; G. Diósi

2002-01-01

203

Anaerobic and Aerobic Beer Aging  

Microsoft Academic Search

Šavel J., Košin P., Brož A. (2010): Anaerobic and aerobic beer aging . Czech J. Food Sci., 28: 18-26. Yellow, orange, red and brown pigments are formed by air oxidation of single polyphenols or by thermal degradation of sugars to caramels. Caramels increase their colours during anaerobic heating or decrease them by air oxidation. Epicatechin and caramel undergo reversible redox

Budweiser Budvar

2010-01-01

204

Na-alginate, and for comparative pur-poses, pectin were fed to faecal bacteria cul-  

E-print Network

Na-alginate, and for comparative pur- poses, pectin were fed to faecal bacteria cul- tured enrichment. Pectine decreased Fusobacterium sp populations whereas algi- nate selected for aerobes microorganisms. Bifidobacterial numbers were increased by alginate and decreased by pectine, however

Paris-Sud XI, UniversitƩ de

205

Aerobic bacterial flora of addled raptor eggs in Saskatchewan.  

PubMed

In south-central Saskatchewan, Canada, in 1986, 1987 and 1989, the aerobic bacterial flora was evaluated from 75 unhatched raptor eggs of three species: 42 of the Swainson's hawk (Buteo Swainsoni), 21 of the ferruginous hawk (Buteo regalis), and 12 of the great horned owl (Bubo virginianus). In addled Swainson's hawk eggs, the most common bacterial genera were Enterobacter (18 eggs), Escherichia (12), and Streptococcus (10). Seven great horned owl eggs and six ferruginous hawk eggs also contained Escherichia coli. Salmonella spp. were not isolated. These bacteria were interpreted as secondary contaminants and not the primary cause of reproductive failure. PMID:9131569

Houston, C S; Saunders, J R; Crawford, R D

1997-04-01

206

Mass culture of magnetic bacteria and their application to flow type immunoassays  

Microsoft Academic Search

Isolated helical magnetotactic bacteria were cultured in a medium containing succinate, nitrate, and ferric malate as carbon, nitrogen, and iron sources, respectively. The magnetotactic bacteria could grow aerobically. The cells which grew aerobically had oxidase activity. An initial inoculum of 105 cells\\/ml was used. Stationary phase was reached 1.4×109 cells\\/ml after 4-5 days growth. When the cells were disrupted using

T. Matsunaga; F. Tadokoro; N. Nakamura

1990-01-01

207

Description of Mariniphaga anaerophila gen. nov., sp. nov., a facultatively aerobic marine bacterium isolated from tidal flat sediment, reclassification of the Draconibacteriaceae as a later heterotypic synonym of the Prolixibacteraceae and description of the family Marinifilaceae fam. nov.  

PubMed

A mesophilic, chemoheterotrophic bacterium, strain Fu11-5(T), was isolated from tidal-flat sediment from Tokyo Bay, Chiba, Japan. Cells of strain Fu11-5(T) were facultatively aerobic, Gram-negative, non-sporulating, non-motile and rod-shaped (1.9-6.9 µm long). Strain Fu11-5(T) grew optimally at 35-37 °C and pH 6.5-7.0 and with 1-2?% (w/v) NaCl. Oxygen and l-cysteine were used as an alternative electron acceptor and donor, respectively. Strain Fu11-5(T) also grew fermentatively on some pentoses, hexoses and disaccharides and soluble starch. Succinic acid was the major end product from d-glucose. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain Fu11-5(T) was affiliated with the order Bacteroidales, and its nearest neighbours were members of the genera Meniscus, Prolixibacter, Sunxiuqinia, Mangrovibacterium and Draconibacterium, with 87-91?% sequence similarity. Cell morphology, optimum growth temperature and utilization of sugars of strain Fu11-5(T) distinguished the strain from phylogenetically related bacteria. On the basis of its phenotypic features and phylogenetic position, a novel genus and species are proposed to accommodate strain Fu11-5(T), with the name Mariniphaga anaerophila gen. nov., sp. nov. The type strain of Mariniphaga anaerophila is strain Fu11-5(T) (?=?JCM 18693(T)?=?NBRC 109408(T)?=?DSM 26910(T)). We also propose to combine the family Draconibacteriaceae into the family Prolixibacteraceae as a later heterotypic synonym and to place the distinct sublineage of the genus Marinifilum in the family Marinifilaceae fam. nov. PMID:25096325

Iino, Takao; Mori, Koji; Itoh, Takashi; Kudo, Takuji; Suzuki, Ken-Ichiro; Ohkuma, Moriya

2014-11-01

208

Comparative study of laboratory-scale thermophilic and mesophilic activated sludge processes  

Microsoft Academic Search

Laboratory-scale mesophilic (20–35°C) and thermophilic (55°C) activated sludge processes (ASPs) treating diluted molasses wastewater were compared in effluent quality, removal of different COD fractions, sludge yield, floc size, and sludge settleability. The effect of polyaluminium chloride (PAC) with high cationic charge on sludge settleability and effluent quality was also studied. In the ASPs, the hydraulic retention time was 12h in

J. Suvilampi; A. Lehtomäki; J. Rintala

2005-01-01

209

Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Catalytic mechanisms of thermophilic-mesophilic enzymes may differ. Black-Right-Pointing-Pointer Product release is rate-determining for thermophilic IGPS at low temperatures. Black-Right-Pointing-Pointer But at higher temperatures, proton transfer from the general acid is rate-limiting. Black-Right-Pointing-Pointer Rate-determining step is different still for mesophilic IGPS. Black-Right-Pointing-Pointer Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 Degree-Sign C for thermophilic IGPS, near its adaptive temperature (75 Degree-Sign C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO{sub 2} release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.

Zaccardi, Margot J.; Mannweiler, Olga [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States); Boehr, David D., E-mail: ddb12@psu.edu [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)

2012-02-10

210

Anaerobic and aerobic degradation of pyridine by a newly isolated denitrifying bacterium.  

PubMed Central

New denitrifying bacteria that could degrade pyridine under both aerobic and anaerobic conditions were isolated from industrial wastewater. The successful enrichment and isolation of these strains required selenite as a trace element. These isolates appeared to be closely related to Azoarcus species according to the results of 16S rRNA sequence analysis. An isolated strain, pF6, metabolized pyridine through the same pathway under both aerobic and anaerobic conditions. Since pyridine induced NAD-linked glutarate-dialdehyde dehydrogenase and isocitratase activities, it is likely that the mechanism of pyridine degradation in strain pF6 involves N-C-2 ring cleavage. Strain pF6 could degrade pyridine in the presence of nitrate, nitrite, and nitrous oxide as electron acceptors. In a batch culture with 6 mM nitrate, degradation of pyridine and denitrification were not sensitively affected by the redox potential, which gradually decreased from 150 to -200 mV. In a batch culture with the nitrate concentration higher than 6 mM, nitrite transiently accumulated during denitrification significantly inhibited cell growth and pyridine degradation. Growth yield on pyridine decreased slightly under denitrifying conditions from that under aerobic conditions. Furthermore, when the pyridine concentration used was above 12 mM, the specific growth rate under denitrifying conditions was higher than that under aerobic conditions. Considering these characteristics, a newly isolated denitrifying bacterium, strain pF6, has advantages over strictly aerobic bacteria in field applications. PMID:9212408

Rhee, S K; Lee, G M; Yoon, J H; Park, Y H; Bae, H S; Lee, S T

1997-01-01

211

Mesophilic and thermophilic anaerobic co-digestion of rendering plant and slaughterhouse wastes.  

PubMed

Co-digestion of rendering and slaughterhouse wastes was studied in laboratory scale semi-continuously fed continuously stirred tank reactors (CSTRs) at 35 and 55 °C. All in all, 10 different rendering plant and slaughterhouse waste fractions were characterised showing high contents of lipids and proteins, and methane potentials of 262-572 dm(3)CH(4)/kg volatile solids(VS)(added). In mesophilic CSTR methane yields of ca 720 dm(3) CH(4)/kg VS(fed) were obtained with organic loading rates (OLR) of 1.0 and 1.5 kg VS/m(3) d, and hydraulic retention time (HRT) of 50 d. For thermophilic process, the lowest studied OLR of 1.5 kg VS/m(3) d, turned to be unstable after operation of 1.5 HRT, due to accumulating ammonia, volatile fatty acids (VFAs) and probably also long chain fatty acids (LCFAs). In conclusion, mesophilic process was found to be more feasible for co-digestion than thermophilic process, methane yields being higher and process more stable in mesophilic conditions. PMID:22074907

Bayr, Suvi; Rantanen, Marianne; Kaparaju, Prasad; Rintala, Jukka

2012-01-01

212

Performance comparison between mesophilic and thermophilic anaerobic reactors for treatment of palm oil mill effluent.  

PubMed

The anaerobic digestion of palm oil mill effluent (POME) was carried out under mesophilic (37°C) and thermophilic (55°C) conditions without long-time POME storage in order to compare the performance of each condition in the field of Sumatra Island, Indonesia. The anaerobic treatment system was composed of anaerobic hybrid reactor and anaerobic baffled filter. Raw POME was pretreated by screw decanter to reduce suspended solids and residual oil. The total COD removal rate of 90-95% was achieved in both conditions at the OLR of 15kg[COD]/m(3)/d. The COD removal in thermophilic conditions was slightly better, however the biogas production was much higher than that in the mesophilic one at high OLR. The organic contents in pretreated POME were highly biodegradable in mesophilic under the lower OLRs. The biogas production was 13.5-20.0l/d at the 15kg[COD]/m(3)/d OLR, and the average content of carbon dioxide was 5-35% in both conditions. PMID:24797939

Jeong, Joo-Young; Son, Sung-Min; Pyon, Jun-Hyeon; Park, Joo-Yang

2014-08-01

213

A single aromatic core mutation converts a designed "primitive" protein from halophile to mesophile folding.  

PubMed

The halophile environment has a number of compelling aspects with regard to the origin of structured polypeptides (i.e., proteogenesis) and, instead of a curious niche that living systems adapted into, the halophile environment is emerging as a candidate "cradle" for proteogenesis. In this viewpoint, a subsequent halophile-to-mesophile transition was a key step in early evolution. Several lines of evidence indicate that aromatic amino acids were a late addition to the codon table and not part of the original "prebiotic" set comprising the earliest polypeptides. We test the hypothesis that the availability of aromatic amino acids could facilitate a halophile-to-mesophile transition by hydrophobic core-packing enhancement. The effects of aromatic amino acid substitutions were evaluated in the core of a "primitive" designed protein enriched for the 10 prebiotic amino acids (A,D,E,G,I,L,P,S,T,V)-having an exclusively prebiotic core and requiring halophilic conditions for folding. The results indicate that a single aromatic amino acid substitution is capable of eliminating the requirement of halophile conditions for folding of a "primitive" polypeptide. Thus, the availability of aromatic amino acids could have facilitated a critical halophile-to-mesophile protein folding adaptation-identifying a selective advantage for the incorporation of aromatic amino acids into the codon table. PMID:25297559

Longo, Liam M; Tenorio, Connie A; Kumru, Ozan S; Middaugh, C Russell; Blaber, Michael

2015-01-01

214

Structure, Stability, and Folding of Ribonuclease H1 from the Moderately Thermophilic Chlorobium tepidum: Comparison with Thermophilic and Mesophilic Homologues†  

PubMed Central

Proteins from thermophilic organisms are able to function under conditions that render a typical mesophilic protein inactive. Pairwise comparisons of homologous mesophilic and thermophilic proteins can help to identify the energetic features of a protein’s energy landscape that lead to such thermostability. Previous studies of bacterial ribonucleases H (RNases H) from the thermophile Thermus thermophilus and the mesophile Escherichia coli revealed that the thermostability arises in part from an unusually low change in heat capacity upon unfolding (?Cp) for the thermophilic protein. Here, we have further examined how nearly identical proteins can adapt to different thermal constraints by adding a moderately thermophilic homologue to the previously characterized mesophilic and thermophilic pair. We identified a putative RNase H from Chlorobium. tepidum and demonstrated that it is an active RNase H and adopts the RNase H fold. The moderately thermophilic protein has a melting temperature (Tm) similar to that of the mesophilic homologue yet also has a surprisingly low ?Cp, like the thermophilic homologue. This new RNase H folds through a pathway similar to that of the previously studied RNases H. These results suggest that lowering the ?Cp may be a general strategy for achieving thermophilicity for some protein families and implicate the folding core as the major contributor to this effect. It should now be possible to design RNases H that display the desired thermophilic or mesophilic properties, as defined by their ?Cp values, and therefore fine-tune the energy landscape in a predictable fashion. PMID:19408959

Ratcliff, Kathleen; Corn, Jacob; Marqusee, Susan

2010-01-01

215

Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures.  

PubMed

Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25°C for thermophilic IGPS, near its adaptive temperature (75°C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO2 release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards. PMID:22274606

Zaccardi, Margot J; Mannweiler, Olga; Boehr, David D

2012-02-10

216

Performance evaluation of a completely stirred anaerobic reactor treating pig manure at a low range of mesophilic conditions  

SciTech Connect

Highlights: • The biogas process can run stably at 20 °C at extremely low OLR after long-term acclimation of bacteria. • A biogas plant running at 28 °C seems as efficient as that operated at 38 °C at low OLR of 1.3 g ODM L{sup ?1} d{sup ?1}. • Lower temperature operation is inadvisable for the commercial biogas plant running at rather high OLR. • The estimated sludge yield at 28 °C is higher than that at 38 °C. - Abstract: Many Chinese biogas plants run in the lower range of mesophilic conditions. This study evaluated the performance of a completely stirred anaerobic reactor treating pig manure at different temperatures (20, 28 and 38 °C). The start-up phase of the reactor at 20 °C was very long and extremely poor performance was observed with increasing organic loading rate (OLR). At an OLR of 4.3 g ODM L{sup ?1} d{sup ?1}, methane production at 28 °C was comparable (3% less) with that at 38 °C, but the risk of acidification was high at 28 °C. At low OLR (1.3 g ODM L{sup ?1} d{sup ?1}), the biogas process appeared stable at 28 °C and gave same methane yields as compared to the reactor operating at 38 °C. The estimated sludge yield at 28 °C was 0.065 g VSS g{sup ?1} COD{sub removed,} which was higher than that at 38 °C (0.016 g VSS g{sup ?1} COD{sub removed})

Guo, Jianbin, E-mail: jianbinguo@gmail.com [Department of Environmental Engineering, Tsinghua University, Beijing 100084 (China); Dong, Renjie [College of Engineering, China Agricultural University, P.O. Box 184, Beijing 100083 (China); Clemens, Joachim [Institute of Crop Science and Resource Reservation (INRES), University of Bonn, Karlrobert-Kreiten-Strasse 13, 53115 Bonn (Germany); Wang, Wei [Department of Environmental Engineering, Tsinghua University, Beijing 100084 (China)

2013-11-15

217

[The aerobic bacterial intestinal flora of various wintering geese species].  

PubMed

The aerobic fecal flora of wintering Brent Goos (Branta bernicla), Barnacle Goose (Branta leucopsis), Greylag Goose (Anser anser), White-fronted Goose (Anser albifrons), Pink-footed Goose (Anser brachyrhynchus), and Bean Goose (Anser fabalis) was studied. There were no specific differences between the various geese. Bacterial counts were in the range of 10(5)-10(7) CPU per gram of feces. Neither pathogenic bacteria nor rotavirus could be detected in the fecal samples of the wintering geese, so that a contamination of the environment with those pathogenic organisms could be excluded. The majority of the isolated bacteria belonged to the genera Bacillus and Pseudomonas; enterobacteria and streptococci were less common. The observations are discussed regarding their epidemiological and ecological significance. PMID:7136353

Holländer, R

1982-07-01

218

Aerobic granules cultivated and operated in continuous-flow bioreactor under particle-size selective pressure.  

PubMed

A novel method based on the selective pressure of particle size (particle-size cultivation method, PSCM) was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity (settling-velocity cultivation method, SVCM). Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids (MLSS) in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrification and phosphorus removal, but lower settling velocity. Under long term operation of more than 30days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand (COD), NH4(+)-N, total nitrogen (TN) and total phosphorus (TP) removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors. PMID:25458675

Liu, Hongbo; Xiao, Hang; Huang, Shuai; Ma, Huijun; Liu, He

2014-11-01

219

Bacteria Transformation  

NSDL National Science Digital Library

Students construct paper recombinant plasmids to simulate the methods genetic engineers use to create modified bacteria. They learn what role enzymes, DNA and genes play in the modification of organisms. For the particular model they work on, they isolate a mammal insulin gene and combine it with a bacteria's gene sequence (plasmid DNA) for production of the protein insulin.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

220

Isolation and characterization of quinoline-degrading bacteria from subsurface sediments.  

PubMed Central

Two gram-negative, motile bacteria isolated from deep subsurface sediments mineralized the nitrogen-containing polyaromatic hydrocarbon quinoline under aerobic conditions and transformed quinoline to soluble intermediates under anaerobic conditions. Many aromatic compounds were also able to serve as the sole source of carbon and energy under aerobic conditions. Rapid aerobic mineralization of quinoline at concentrations as low as 0.002 microgram ml-1 indicates that these organisms possess a high-affinity uptake and utilization system, which may reflect the oligotrophic nature of deep subsurface environments. Both bacteria harbored four plasmids of identical size, ranging from 50 to 440 kilobases. Images PMID:2729977

Brockman, F J; Denovan, B A; Hicks, R J; Fredrickson, J K

1989-01-01

221

Anaerobic degradation and carbon isotopic fractionation of alkylbenzenes in crude oil by sulphate-reducing bacteria  

Microsoft Academic Search

A mesophilic enrichment culture of sulphate-reducing bacteria isolated from the water phase of a North Sea oil tank using oil from the same tank as sole source of carbon and energy specifically depletes certain C1–C5 alkylbenzenes in crude oil during growth. The enrichment culture grows on oils of different origin and composition resulting in similar patterns of alkylbenzene depletion. Two

Heinz Wilkes; Chris Boreham; Gerda Harms; Karsten Zengler; Ralf Rabus

2000-01-01

222

Isolation and biological characteristics of aerobic marine magnetotactic bacterium YSC-1  

NASA Astrophysics Data System (ADS)

Magnetotactic bacteria have become a hot spot of research in microbiology attracting intensive interest of researchers in multiple disciplinary fields. However, the studies were limited in few fastidious bacteria. The objective of this study aims at isolating new marine magnetic bacteria and better comprehension of magnetotactic bacteria. In this study, an aerobic magnetotactic bacterium YSC-1 was isolated from sediments in the Yellow Sea Cold Water Mass (YSCWM). In TEM, magnetic cells have one or several circular magnetosomes in diameter of 100nm, and consist of Fe and Co shown on energy dispersive X-ray spectrum. The biological and physiological characteristics of this bacterium were also described. The colour of YSC-1 colony is white in small rod. The gram stain is negative. Results showed that Strain YSC-1 differs from microaerophile magnetotactic bacteria MS-1 and WD-1 in biology.

Gao, Jun; Pan, Hongmiao; Yue, Haidong; Song, Tao; Zhao, Yong; Chen, Guanjun; Wu, Longfei; Xiao, Tian

2006-12-01

223

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 PMID:16345777

Wichlacz, Paul L.; Unz, Richard F.

1981-01-01

224

Simulation of wastewater treatment by aerobic granules in a sequencing batch reactor based on cellular automata.  

PubMed

In the present paper, aerobic granules were developed in a sequencing batch reactor (SBR) using synthetic wastewater, and 81 % of granular rate was obtained after 15-day cultivation. Aerobic granules have a 96 % BOD removal to the wastewater, and the reactor harbors a mount of biomass including bacteria, fungi and protozoa. In view of the complexity of kinetic behaviors of sludge and biological mechanisms of the granular SBR, a cellular automata model was established to simulate the process of wastewater treatment. The results indicate that the model not only visualized the complex adsorption and degradation process of aerobic granules, but also well described the BOD removal of wastewater and microbial growth in the reactor. Thus, CA model is suitable for simulation of synthetic wastewater treatment. This is the first report about dynamical and visual simulation of treatment process of synthetic wastewater in a granular SBR. PMID:24696379

Benzhai, Hai; Lei, Liu; Ge, Qin; Yuwan, Peng; Ping, Li; Qingxiang, Yang; Hailei, Wang

2014-10-01

225

Conventional mesophilic vs. thermophilic anaerobic digestion: a trade-off between performance and stability?  

PubMed

A long-term comparative study using continuously-stirred anaerobic digesters (CSADs) operated at mesophilic and thermophilic temperatures was conducted to evaluate the influence of the organic loading rate (OLR) and chemical composition on process performance and stability. Cow manure was co-digested with dog food, a model substrate to simulate a generic, multi-component food-like waste and to produce non-substrate specific, composition-based results. Cow manure and dog food were mixed at a lower - and an upper co-digestion ratio to produce a low-fiber, high-strength substrate, and a more recalcitrant, lower-strength substrate, respectively. Three increasing OLRs were evaluated by decreasing the CSADs hydraulic retention time (HRT) from 20 to 10 days. At longer HRTs and lower manure-to-dog food ratio, the thermophilic CSAD was not stable and eventually failed as a result of long-chain fatty acid (LCFA) accumulation/degradation, which was triggered by the compounded effects of temperature on reaction rates, mixing intensity, and physical state of LCFAs. At shorter HRTs and upper manure-to-dog food ratio, the thermophilic CSAD marginally outperformed the biomethane production rates and substrate stabilization of the mesophilic CSAD. The increased fiber content relative to lipids at upper manure-to-dog food ratios improved the stability and performance of the thermophilic process by decreasing the concentration of LCFAs in solution, likely adsorbed onto the manure fibers. Overall, results of this study show that stability of the thermophilic co-digestion process is highly dependent on the influent substrate composition, and particularly for this study, on the proportion of manure to lipids in the influent stream. In contrast, mesophilic co-digestion provided a more robust and stable process regardless of the influent composition, only with marginally lower biomethane production rates (i.e., 7%) for HRTs as short as 10 days (OLR = 3 g VS/L-d). PMID:24530545

Labatut, Rodrigo A; Angenent, Largus T; Scott, Norman R

2014-04-15

226

Net energy production associated with pathogen inactivation during mesophilic and thermophilic anaerobic digestion of sewage sludge.  

PubMed

The potential for anaerobic digester energy production must be balanced with the sustainability of reusing the resultant biosolids for land application. Mesophilic, thermophilic, temperature-phased, and high temperature (60 or 70 °C) batch pre-treatment digester configurations have been systematically evaluated for net energy production and pathogen inactivation potential. Energy input requirements and net energy production were modeled for each digester scheme. First-order inactivation rate coefficients for Escherichia coli, Enterococcus faecalis and bacteriophage MS-2 were measured at each digester temperature and full-scale pathogen inactivation performance was estimated for each indicator organism and each digester configuration. Inactivation rates were found to increase dramatically at temperatures above 55 °C. Modeling full-scale performance using retention times based on U.S. EPA time and temperature constraints predicts a 1-2 log inactivation in mesophilic treatment, and a 2-5 log inactivation in 50-55 °C thermophilic and temperature-phased treatments. Incorporating a 60 or 70 °C batch pre-treatment phase resulted in dramatically higher potency, achieving MS-2 inactivation of 14 and 16 logs respectively, and complete inactivation (over 100 log reduction) of E. coli and E. faecalis. For temperatures less than 70 °C, viability staining of thermally-treated E. coli showed significantly reduced inactivation relative to standard culture enumeration. Due to shorter residence times in thermophilic reactors, the net energy production for all digesters was similar (less than 20% difference) with the 60 or 70 °C batch treatment configurations producing the most net energy and the mesophilic treatment producing the least. Incorporating a 60 or 70 °C pre-treatment phase can dramatically increase pathogen inactivation performance without decreasing net energy capture from anaerobic digestion. Energy consumption is not a significant barrier against improving the pathogen quality of biosolids. PMID:21764416

Ziemba, Christopher; Peccia, Jordan

2011-10-15

227

Microbial Composition and Structure of Aerobic Granular Sewage Biofilms?  

PubMed Central

Aerobic activated sludge granules are dense, spherical biofilms which can strongly improve purification efficiency and sludge settling in wastewater treatment processes. In this study, the structure and development of different granule types were analyzed. Biofilm samples originated from lab-scale sequencing batch reactors which were operated with malthouse, brewery, and artificial wastewater. Scanning electron microscopy, light microscopy, and confocal laser scanning microscopy together with fluorescence in situ hybridization (FISH) allowed insights into the structure of these biofilms. Microscopic observation revealed that granules consist of bacteria, extracellular polymeric substances (EPS), protozoa and, in some cases, fungi. The biofilm development, starting from an activated sludge floc up to a mature granule, follows three phases. During phase 1, stalked ciliated protozoa of the subclass Peritrichia, e.g., Epistylis spp., settle on activated sludge flocs and build tree-like colonies. The stalks are subsequently colonized by bacteria. During phase 2, the ciliates become completely overgrown by bacteria and die. Thereby, the cellular remnants of ciliates act like a backbone for granule formation. During phase 3, smooth, compact granules are formed which serve as a new substratum for unstalked ciliate swarmers settling on granule surfaces. These mature granules comprise a dense core zone containing bacterial cells and EPS and a loosely structured fringe zone consisting of either ciliates and bacteria or fungi and bacteria. Since granules can grow to a size of up to several millimeters in diameter, we developed and applied a modified FISH protocol for the study of cryosectioned biofilms. This protocol allows the simultaneous detection of bacteria, ciliates, and fungi in and on granules. PMID:17704280

Weber, S. D.; Ludwig, W.; Schleifer, K.-H.; Fried, J.

2007-01-01

228

Composting of explosives and propellant contaminated soils under thermophilic and mesophilic conditions  

Microsoft Academic Search

Summary Composting was investigated as a bioremediation technology for clean-up of sediments contaminated with explosives and propellants. Two field demonstrations were conducted, the first using 2,4,6-trinitrotoluene (TNT), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and N-methyl-N,2,4,6-tetranitroaniline (tetryl) contaminated sediment, and the second using nitrocellulose (NC) contaminated soil. Tests were conducted in thermophilic and mesophilic aerated static piles. Extractable TNT was reduced from 11840

Richard T. Williams; P. Scott Ziegenfuss; Wayne E. Sisk

1992-01-01

229

Local entropy difference upon a substrate binding of a psychrophilic ?-amylase and a mesophilic homologue  

NASA Astrophysics Data System (ADS)

Psychrophilic ?-amylase from the antarctic bacterium pseudoalteromonashaloplanktis (AHA) and its mesophilic homologue, porcine pancreatic ?-amylase (PPA) are theoretically investigated with molecular dynamics (MD) simulations. We carried out 240-ns MD simulations for four systems, AHA and PPA with/without the bound substrate, and examined protein conformational entropy changes upon the substrate binding. We developed an analysis that decomposes the entropy changes into contributions of individual amino acids, and successfully identified protein regions responsible for the entropy changes. The results provide a molecular insight into the structural flexibilities of those enzymes related to the temperature dependences of the enzymatic activity.

Kosugi, Takahiro; Hayashi, Shigehiko

2011-01-01

230

Biosorption of heavy metals by bacteria isolated from activated sludge  

Microsoft Academic Search

Twelve aerobic bacteria from activated sludge were isolated and identified. These included both Gram-positive (e.g., Bacillus) and Gram-negative (e.g., Pseudomonas) bacteria. The biosorption capacity of these strains for three different heavy metals (copper, nickel, and lead) was determined\\u000a at pH 5.0 and initial metal concentration of 100 mg\\/L. Among these 12 isolates, Pseudomonas pseudoalcaligenes was selected for further investigation owing

Wa C. Leung; Hong Chua; Waihung Lo

2001-01-01

231

Degradation of Phthalic Acids by Denitrifying, Mixed Cultures of Bacteria  

PubMed Central

Mixed cultures of bacteria, enriched from aquatic sediments, grew anaerobically on all three isomers of phthalic acid. Each culture grew anaerobically on only one isomer and also grew aerobically on the same isomer. Pure cultures were isolated from the phthalic acid (o-phthalic acid) and isophthalic acid (m-phthalic acid) enrichments that grew aerobically on phthalic and isophthalic acids. Cell suspension experiments indicated that protocatechuate is an intermediate of aerobic catabolism. Pure cultures which grew aerobically on terephthalic acid (p-phthalic acid) could not be isolated from the enrichments, and neither could pure cultures that grew anaerobically on any of the isomers. Cell suspension experiments suggested that separate pathways exist for the aerobic and anaerobic oxidation of phthalic acids. Each enrichment culture used only one phthalic acid isomer under anaerobic conditions, but all isomers were simultaneously adapted for the anaerobic catabolism of benzoate. Cells grown anaerobically on a phthalic acid immediately attacked the isomer under anaerobic conditions, whereas there was a lag before aerobic breakdown occurred, and, for phthalic and terephthalic acids, chloramphenicol stopped aerobic adaptation but had no effect on anaerobic catabolism. This work suggests that phthalic acids are biodegradable in anaerobic environments. PMID:16345769

Aftring, R. Paul; Chalker, Bruce E.; Taylor, Barrie F.

1981-01-01

232

Measuring aerobic fitness in divers.  

PubMed

The editorial by Bosco, Paoli and Camporesi in the last issue of this journal provides an interesting overview of some of the factors that are either known or suspected to be important in the physiological health of divers. The part pertinent to our paper concerns the meaning and use of metabolic equivalents (MET). Our goal was to estimate the metabolic effort required for a substantial sample of recreational dives. Computing MET values based on an assumed resting oxygen consumption rate of 3.5 millilitres of oxygen per kilogram body mass per minute is well established. Most pointedly, MET is used in the Recreational Scuba Training Council (RSTC) Guidelines for Recreational Scuba Diver's Physical Examination found in the Medical Statement documentation. Given the increasingly widespread use of the RSTC assessment, it makes the most sense to be consistent. Concerns over whether or not a more appropriate index value could be used are moot. Anyone wishing to compute a different base for 1.0 MET can simply crossmultiply and divide. The question to be answered is not what level of aerobic capacity is desirable for divers, the answer to that is the higher the better. The critical question is what constitutes a reasonable minimum threshold aerobic capacity consistent with operational safety. The authors mention the often invoked 13 MET capacity identified as a threshold for US Navy divers. What is typically ignored, however, is the fact that the Navy has far more applicants for dive school than posts to be filled, making very stringent selection standards feasible even if not truly operationally necessary. It is not at all clear that this is a reasonable threshold for the broader diving community. Despite this, the RSTC documentation adheres to the traditional position. "Formalized stress testing is encouraged if there is any doubt regarding physical performance capability. The suggested minimum criteria for stress testing in such cases is at least 13 METS [sic]. Failure to meet the exercise criteria would be of significant concern." This is contrary to the available data. A review of 14 studies in which the aerobic capacity of divers was measured found that mean aerobic fitness ranged from 37-57 mL?kg?¹?min?¹ (10.6-16.3 MET). The lowest individual scores were below 5.0 MET. The threshold of 13 MET was exceeded by the group mean in only six of the 14 studies described. This certainly does not support 13 MET as a meaningful threshold for participation. Our current work was intended as a simple effort to begin to assess the aerobic demands of recreational diving. It is our hope to promote discussion that is willing to risk the heresy of challenging conventional wisdom and to stimulate additional research. We certainly agree with the authors and feel strongly that enhanced in-water evaluation of physical fitness is desirable to establish diver readiness. We would not, however, refer to this as a "medical examination" since it is likely that it will largely be dive professionals and not clinicians that conduct the evaluations. PMID:25311329

Pollock, Neal W; Buzzacott, Peter

2014-09-01

233

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia.  

PubMed

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD(+)/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R; Cook, Gregory M

2014-08-01

234

An obligately aerobic soil bacterium activates fermentative hydrogen production to survive reductive stress during hypoxia  

PubMed Central

Oxygen availability is a major factor and evolutionary force determining the metabolic strategy of bacteria colonizing an environmental niche. In the soil, conditions can switch rapidly between oxia and anoxia, forcing soil bacteria to remodel their energy metabolism accordingly. Mycobacterium is a dominant genus in the soil, and all its species are obligate aerobes. Here we show that an obligate aerobe, the soil actinomycete Mycobacterium smegmatis, adopts an anaerobe-type strategy by activating fermentative hydrogen production to adapt to hypoxia. This process is controlled by the two-component system DosR-DosS/DosT, an oxygen and redox sensor that is well conserved in mycobacteria. We show that DosR tightly regulates the two [NiFe]-hydrogenases: Hyd3 (MSMEG_3931-3928) and Hyd2 (MSMEG_2719-2718). Using genetic manipulation and high-sensitivity GC, we demonstrate that Hyd3 facilitates the evolution of H2 when oxygen is depleted. Combined activity of Hyd2 and Hyd3 was necessary to maintain an optimal NAD+/NADH ratio and enhanced adaptation to and survival of hypoxia. We demonstrate that fermentatively-produced hydrogen can be recycled when fumarate or oxygen become available, suggesting Mycobacterium smegmatis can switch between fermentation, anaerobic respiration, and aerobic respiration. Hydrogen metabolism enables this obligate aerobe to rapidly meet its energetic needs when switching between microoxic and anoxic conditions and provides a competitive advantage in low oxygen environments. PMID:25049411

Berney, Michael; Greening, Chris; Conrad, Ralf; Jacobs, William R.; Cook, Gregory M.

2014-01-01

235

The effects of wilting and storage temperatures on the fermentation quality and aerobic stability of stylo silage.  

PubMed

In order to clarify the ensiling characteristics of stylo (Stylosanthes guianensis Swartz), the effects of wilting (no wilting, light wilting and heavy wilting) and storage temperatures (10°C, 20°C, 30°C and 40°C) on the fermentation quality and aerobic stability of stylo silage were investigated. Wilting had no significant influence on the contents of crude protein, ether extract and acid detergent fiber, and numbers of lactic acid bacteria, aerobic bacteria, yeasts and mold (P > 0.05). Heavy wilted material, wilted for 12 h, had higher neutral detergent fiber content and lower water-soluble carbohydrate content than unwilted and light wilted materials (P < 0.05). Wilting and storage temperatures had significant effects on pH value, acetic acid, butyric acid and NH(3) -N contents of stylo silage (P < 0.01 or P < 0.05). Wilting tended to reduce acetic acid and NH(3) -N contents and improve the fermentation quality of stylo silage. In all the silages, no wilting silage ensiled at 30°C had the highest butyric acid content (P < 0.05). High temperature of 40°C markedly restricted the growth of lactic acid bacteria and aerobic bacteria in silage, irrespective of wilting. The wilted silage or silage stored at low temperature had poor aerobic stability. PMID:21794013

Liu, Qinghua; Zhang, Jianguo; Shi, Shangli; Sun, Qizhong

2011-08-01

236

Comparative In Vitro Activities of GAR936 against Aerobic and Anaerobic Animal and Human Bite Wound Pathogens  

Microsoft Academic Search

GAR-936 is a new semisynthetic glycylcycline with a broad antibacterial spectrum, including tetracycline- resistant strains. The in vitro activities of GAR-936, minocycline, doxycycline, tetracycline, moxifloxacin, penicillin G, and erythromycin were determined by agar dilution methods against 268 aerobic and 148 anaerobic strains of bacteria (including Pasteurella, Eikenella, Moraxella, Bergeyella, Neisseria, EF-4, Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Staphylococcus, Streptococcus, Enterococcus, Corynebacterium, Propi-

ELLIE J. C. GOLDSTEIN; DIANE M. CITRON; C. VRENI MERRIAM; YUMI WARREN; KERIN TYRRELL

2000-01-01

237

STANDARDIZING AEROBIC INCUBATION METHODS: IS IT POSSIBLE?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A single silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at seven USDA-ARS locations u...

238

STANDARDIZING AEROBIC INCUBATION METHODS: IS IT POSSIBLE?  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A single silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at six USDA-ARS locations usi...

239

Aerobic Fitness: What Are We Measuring?  

Microsoft Academic Search

Aerobic fitness depends upon the components of oxygen delivery and the oxidative mechanisms of the exercising muscle. Peak oxygen uptake is recognised as the best single criterion of aerobic fitness but it is strongly correlated with body size. Methods of controlling for body size are discussed and it is demonstrated how inappropriate use of ratio scaling has clouded our understanding

N. Armstrong; J. Welsman

2007-01-01

240

Aerobic Fitness for the Moderately Retarded.  

ERIC Educational Resources Information Center

Intended for physical education teachers, the booklet offers ideas for incorporating aerobic conditioning into programs for moderately mentally retarded students. An explanation of aerobic fitness and its benefits is followed by information on initiating a fitness program with evaluation of height, weight, body fat, resting heart rate, and…

Bauer, Dan

1981-01-01

241

Enrichment, Isolation and Some Properties of Methane-utilizing Bacteria  

Microsoft Academic Search

SUMMARY More than IOO Gram-negative, strictly aerobic, methane-utilizing bacteria were isolated. All used only methane and methanol of the substrates tested for growth. The organisms were classified into five groups on the basis of mor- phology, fine structure, and type of resting stage formed (exospores and different types of cysts) and into subgroups on other properties. Methods of enrichment, isolation

R. Whittenbury; K. C. Phillips; J. F. Wilkinson

1970-01-01

242

Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs?  

PubMed Central

Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses. PMID:22196374

2011-01-01

243

Integrated anaerobic-aerobic fixed-film reactor for slaughterhouse wastewater treatment.  

PubMed

An integrated anaerobic-aerobic fixed-film pilot-scale reactor with arranged media was fed during 166 days with slaughterhouse wastewater. Operation temperature was 25 degrees C and the anaerobic-aerobic volume ratio was decreased from 4:1 to 3:2 and finally to 2:3. Overall organic matter removal efficiencies of 93% were achieved for an average organic loading rate of 0.77 kg COD/m3 d, and nitrogen removal efficiencies of 67% were achieved for nitrogen loading rates of 0.084 kg N/m3 d. The high internal recirculation associated to the air-lift effect linked to the aeration of a part of the reactor section caused high mixing between the anaerobic and aerobic zones, so that most organic matter was removed aerobically. The nitrification process achieved an efficiency of 91% for nitrogen loads of 0.15 kg N/m3 d when the anaerobic-aerobic volume ratio was 2:3 and was limited by dissolved oxygen concentration below 3 mg/l. The influence of the heterotrophic biomass growing in the outer biofilm was checked. Denitrification only implied the 12-34% of the total nitrogen removal and was limited by dissolved oxygen concentration in the anaerobic zone above 0.5 mg/l caused by the mixing regime. Most removed nitrogen was employed in synthesis of heterotrophic bacteria. PMID:15766966

Del Pozo, R; Diez, V

2005-03-01

244

Clostridium bornimense sp. nov., isolated from a mesophilic, two-phase, laboratory-scale biogas reactor.  

PubMed

A novel anaerobic, mesophilic, hydrogen-producing bacterium, designated strain M2/40(T), was isolated from a mesophilic, two-phase, laboratory-scale biogas reactor fed continuously with maize silage supplemented with 5% wheat straw. 16S rRNA gene sequence comparison revealed an affiliation to the genus Clostridium sensu stricto (cluster I of the clostridia), with Clostridium cellulovorans as the closest characterized species, showing 93.8% sequence similarity to the type strain. Cells of strain M2/40(T) were rods to elongated filamentous rods that showed variable Gram staining. Optimal growth occurred at 35 °C and at pH 7. Grown on glucose, the main fermentation products were H2, CO2, formate, lactate and propionate. The DNA G+C content was 29.6 mol%. The major fatty acids (>10?%) were C(16?:?0), summed feature 10 (C(18?:?1)?11c/?9t/?6t and/or unknown ECL 17.834) and C(18?:?1)?11c dimethylacetal. Based on phenotypic, chemotaxonomic and phylogenetic differences, strain M2/40(T) represents a novel species within the genus Clostridium, for which we propose the name Clostridium bornimense sp. nov. The type strain is M2/40(T) (?=?DSM 25664(T)?=?CECT 8097(T)). PMID:24860110

Hahnke, Sarah; Striesow, Jutta; Elvert, Marcus; Mollar, Xavier Prieto; Klocke, Michael

2014-08-01

245

Mesophilic and thermophilic anaerobic laboratory-scale digestion of Nannochloropsis microalga residues.  

PubMed

This paper studies methane production using a marine microalga, Nannochloropsis sp. residue from biodiesel production. Residue cake from Nannochloropsis, oils wet-extracted, had a methane potential of 482LCH4kg(-1) volatile solids (VS) in batch assays. However, when dry-extracted, the methane potential of residue cake was only 194LCH4kg(-1) VS. In semi-continuous reactor trials with dry-extracted residue cake, a thermophilic reactor produced 48% higher methane yield (220LCH4kg(-1)VS) than a mesophilic reactor (149LCH4kg(-1)VS). The thermophilic reactor was apparently inhibited due to ammonia with organic loading rate (OLR) of 2kgVSm(-3)d(-1) (hydraulic retention time (HRT) 46d), whereas the mesophilic reactor performed with OLR of 3kgVSm(-3)d(-1) (HRT 30d). Algal salt content did not inhibit digestion. Additional methane (18-33% of primary digester yield) was produced during 100d post-digestion. PMID:24462882

Kinnunen, H V; Koskinen, P E P; Rintala, J

2014-03-01

246

Methanotrophic bacteria.  

PubMed Central

Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehyde assimilation, whereas type II methanotrophs, which employ the serine pathway for formaldehyde assimilation, form a coherent cluster within the beta subdivision of the Proteobacteria. Methanotrophic bacteria are ubiquitous. The growth of type II bacteria appears to be favored in environments that contain relatively high levels of methane, low levels of dissolved oxygen, and limiting concentrations of combined nitrogen and/or copper. Type I methanotrophs appear to be dominant in environments in which methane is limiting and combined nitrogen and copper levels are relatively high. These bacteria serve as biofilters for the oxidation of methane produced in anaerobic environments, and when oxygen is present in soils, atmospheric methane is oxidized. Their activities in nature are greatly influenced by agricultural practices and other human activities. Recent evidence indicates that naturally occurring, uncultured methanotrophs represent new genera. Methanotrophs that are capable of oxidizing methane at atmospheric levels exhibit methane oxidation kinetics different from those of methanotrophs available in pure cultures. A limited number of methanotrophs have the genetic capacity to synthesize a soluble methane monooxygenase which catalyzes the rapid oxidation of environmental pollutants including trichloroethylene. PMID:8801441

Hanson, R S; Hanson, T E

1996-01-01

247

Temperatibacter marinus gen. nov., sp. nov., a mesophilic bacterium isolated from surface seawater and description of Temperatibacteraceae fam. nov. in the class Alphaproteobacteria.  

PubMed

A Gram-stain-negative, motile, mesophilic, aerobic, rod-shaped bacterium, strain 5-11(T), was isolated from surface seawater at Muroto city, Kochi prefecture, Japan. The strain exhibited a narrow growth temperature range of 20-30 °C. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain fell within the order Kordiimonadales in the class Alphaproteobacteria and was related most closely to the genus Kordiimonas (up to 91.2?% similarity to the type strains of species of the genus) but branched deeply from species of Kordiimonas. The major fatty acids were iso-C17?:?1?9c, iso-C15?:?0, and C16?:?1?7c and/or iso-C15?:?0 2-OH. Ubiquinone-10 (Q-10) was detected as the sole isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and one unidentified aminolipid. Although strains of Kordiimonas have been shown to contain unidentified glycolipids, they were not detected from strain 5-11(T). The DNA G+C content of strain 5-11(T) was 44.3 mol%, a value that was lower than those of strains of Kordiimonas (50-58 mol%) and was relatively low for the members of the class Alphaproteobacteria. On the basis of phenotypic, genotypic and chemotaxonomic data, it is proposed that strain 5-11(T) represents a novel species of a new genus, Temperatibacter marinus gen. nov., sp. nov., within a new family Temperatibacteraceae fam. nov. The type strain of Temperatibacter marinus is 5-11(T) (?=?NBRC 110045(T)?=?LMG 28278(T)). PMID:24944335

Teramoto, Maki; Nishijima, Miyuki

2014-09-01

248

Methyloligella halotolerans gen. nov., sp. nov. and Methyloligella solikamskensis sp. nov., two non-pigmented halotolerant obligately methylotrophic bacteria isolated from the Ural saline environments.  

PubMed

Two newly isolated halotolerant obligately methylotrophic bacteria (strains C2(T) and SK12(T)) with the serine pathway of C1 assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, non-motile rods, forming rosettes, multiplying by binary fission. Mesophilic and neutrophilic, accumulate intracellularly compatible solute ectoine and poly-?-hydroxybutyrate. The novel strains are able to grow at 0 up to 16% NaCl (w/v), optimally at 3-5% NaCl. The major cellular fatty acids are C18:1?7c and C19:0cyc and the prevailing quinone is Q-10. The predominant phospholipids are phosphatidylcholine, phosphatidylglycerol, phosphatidyldimethylethanolamine and phosphatidylethanolamine. Assimilate NH4(+) by glutamate dehydrogenase and via the glutamate cycle (glutamine synthetase and glutamate synthase). The DNA G+C contents of strains C2(T) and SK12(T) are 60.9 and 60.5 mol% (Tm), respectively. 16S rRNA gene sequence similarity between the two new isolates are 99% but below 94% with other members of the Alphaproteobacteria thus indicating that they can be assigned to a novel genus Methyloligella. Rather low level of DNA-DNA relatedness (53%) between the strains C2(T) and SK12(T) indicates that they represent two separate species of the new genus, for which the names Methyloligella halotolerans gen. nov., sp. nov. and Methyloligella solikamskensis sp. nov. are proposed. The type strain of Methyloligella halotolerans is C2(T) (=VKM B-2706(T)=CCUG 61687(T)=DSM 25045(T)) and the type strain of Methyloligella solikamskensis is SK12(T) (=VKM B-2707(T)=CCUG 61697(T)=DSM 25212(T)). PMID:23351489

Doronina, Nina V; Poroshina, Maria N; Kaparullina, Elena N; Ezhov, Vladimir A; Trotsenko, Yuri A

2013-05-01

249

Pseudomonas aeruginosa aerobic fatty acid desaturase DesB is important for virulence factor production  

Microsoft Academic Search

Unsaturated fatty acids (UFAs) play a pivotal role in maintaining a functional cellular membrane in response to changes in\\u000a environmental factors. Unlike in other gram-negative bacteria, in Pseudomonas aeruginosa, UFA synthesis is governed by 2 pathways: (1) the anaerobic FabAB-mediated pathway and (2) the aerobic inducible DesA\\/DesB\\u000a desaturase pathway. Although fatty acids are functional constituents of several known virulence factors,

Herbert P. Schweizer; Kyoung-Hee Choi

2011-01-01

250

Importance of biofilm formation for corrosion inhibition of SAE 1018 steel by axenic aerobic biofilms  

Microsoft Academic Search

  To investigate if corrosion inhibition by aerobic biofilms is a general phenomenon, carbon steel (SAE 1018) coupons were\\u000a exposed to a complex liquid medium (Luria–Bertani) and seawater-mimicking medium (VNSS) containing fifteen different pure-culture\\u000a bacterial suspensions representing seven genera. Compared to sterile controls, the mass loss in the presence of these bacteria\\u000a (which are capable of developing a biofilm to various

A Jayaraman; E T Cheng; J C Earthman; T K Wood

1997-01-01

251

High rate aerobic treatment of brewery wastewater using the jet loop reactor  

Microsoft Academic Search

An aerobic Jet Loop Reactor (JLR) activated sludge process of 541. volume was used to investigate its suitability for the treatment of industrial wastewaters, specifically brewery wastewater. A loading rate of 50 kg COD\\/m3·d was achieved with 97% COD removal for a period of 5 weeks and although the settleability was found to be acceptable non-flocculating motile bacteria caused the

James C. Bloor; G. K. Anderson; A. R. Willey

1995-01-01

252

Magnetotactic Bacteria  

Microsoft Academic Search

Bacteria with motility directed by the local geomagnetic field have been observed in marine sediments. These magnetotactic microorganisms possess flagella and contain novel structured particles, rich in iron, within intracytoplasmic membrane vesicles. Conceivably these particles impart to cells a magnetic moment. This could explain the observed migration of these organisms in fields as weak as 0.5 gauss.

Richard Blakemore

1975-01-01

253

Aerobic Bacterial Microbiota Isolated from the Cloaca of the European Pond Turtle (Emys orbicularis) in Poland.  

PubMed

Abstract We conducted a comparative analysis of the aerobic cloacal bacteria of European pond turtles (Emys orbicularis) living in their natural environment and juvenile turtles reared under controlled conditions in a breeding center. We included 130 turtles in the study. The aerobic bacteria isolated from the cloaca of the juvenile turtles were less diverse and more prevalent than the bacteria isolated from free-living adults. We isolated 17 bacterial species from juvenile captive turtles, among which the dominant species were Cellulomonas flavigena (77/96), Enterococcus faecalis (96/96), Escherichia coli (58/96), and Proteus mirabilis (41/96). From the adult, free-living turtles, we isolated 36 bacterial species, some of which are a potential threat to public health (e.g., Salmonella enterica serovars Newport, Daytona, and Braenderup; Listeria monocytogenes; Yersinia enterocolitica; Yersinia ruckeri; Klebsiella pneumoniae; Vibrio fluvialis; and Serratia marcescens), and pathogens that are etiologic agents of diseases of ectothermic animals (e.g., Aeromonas sobria, Aeromonas caviae, Hafnia alvei, Edwardsiella tarda, and Citrobacter braakii; the last two species were isolated from both groups of animals). The cloacal bacterial biota of the European pond turtle was characterized by numerous species of bacteria, and its composition varied with turtle age and environmental conditions. The small number of isolated bacteria that are potential human pathogens may indicate that the European pond turtle is of relatively minor importance as a threat to public health. PMID:25380369

Nowakiewicz, Aneta; Zió?kowska, Gra?yna; Zi?ba, Przemys?aw; Dziedzic, Barbara Majer; Gnat, Sebastian; Wójcik, Mariusz; Dziedzic, Roman; Kostruba, Anna

2015-01-01

254

Genome Sequence of the Mesophilic Thermotogales Bacterium Mesotoga prima MesG1.Ag.4.2 Reveals the Largest Thermotogales Genome To Date  

SciTech Connect

Here we describe the genome of Mesotoga prima MesG1.Ag4.2, the first genome of a mesophilic Thermotogales bacterium. Mesotoga prima was isolated from a polychlorinated biphenyl (PCB)-dechlorinating enrichment culture from Baltimore Harbor sediments. Its 2.97 Mb genome is considerably larger than any previously sequenced Thermotogales genomes, which range between 1.86 and 2.30 Mb. This larger size is due to both higher numbers of protein-coding genes and larger intergenic regions. In particular, the M. prima genome contains more genes for proteins involved in regulatory functions, for instance those involved in regulation of transcription. Together with its closest relative, Kosmotoga olearia, it also encodes different types of proteins involved in environmental and cell-cell interactions as compared with other Thermotogales bacteria. Amino acid composition analysis of M. prima proteins implies that this lineage has inhabited low-temperature environments for a long time. A large fraction of the M. prima genome has been acquired by lateral gene transfer (LGT): a DarkHorse analysis suggests that 766 (32%) of predicted protein-coding genes have been involved in LGT after Mesotoga diverged from the other Thermotogales lineages. A notable example of a lineage-specific LGT event is a reductive dehalogenase gene - a key enzyme in dehalorespiration, indicating M. prima may have a more active role in PCB dechlorination than was previously assumed.

Zhaxybayeva, Olga [Dartmouth College; Swithers, Kristen S [University of Connecticut, Storrs; Foght, Julia [University of Alberta, Edmondton, Canada; Green, Anna G. [University of Connecticut; Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Teshima, Hazuki [Los Alamos National Laboratory (LANL); Han, James [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Dlutek, Marlena [Dalhousie University, Halifax, Nova Scotia, CANADA; Doolittle, W. Ford [Dalhousie University, Halifax, Nova Scotia, CANADA; Noll, Kenneth M [University of Connecticut, Storrs; Nesbo, Camilla [University of Oslo, Norway

2012-01-01

255

Identifying risk factors for eggshell contamination by Bacillus cereus group bacteria in French laying farms.  

PubMed

1. The growth of Bacillus cereus group bacteria often limits the shelf-life of pasteurised liquid egg products and is also a putative toxin producer. This study was performed to better understand the route of contamination by B. cereus in egg products by studying the factors affecting eggshell contamination on-farm. 2. Eggs were collected in warm and cold seasons in 50 conventional laying farms in Western France. Egg surfaces were analysed for the presence of B. cereus group bacteria, environmental measurements were recorded and production practices were identified through a questionnaire filled out by the farmers. 3. A total of 44% of the farms were contaminated by mesophilic and 10% by psychrotrophic B. cereus group bacteria. No significant effect of the season was observed, whatever the thermal type. Several procedures were associated with reduced eggshell contamination by mesophilic bacteria, including the limitation of dust formation from manure and feeding and efficient disinfection of the silo, houses and the sanitary wall between houses. 4. The research highlights the need to promote prevention strategies, from farm to fork, for the control of eggshell and putative subsequent egg product contamination by B. cereus group bacteria. PMID:23650940

Kone, A Z; Jan, S; Le Marechal, C; Grosset, N; Gautier, M; Puterflam, J; Baron, F

2013-06-01

256

Adaptation of aerobic respiration to low O2 environments  

PubMed Central

Aerobic respiration in bacteria, Archaea, and mitochondria is performed by oxygen reductase members of the heme-copper oxidoreductase superfamily. These enzymes are redox-driven proton pumps which conserve part of the free energy released from oxygen reduction to generate a proton motive force. The oxygen reductases can be divided into three main families based on evolutionary and structural analyses (A-, B- and C-families), with the B- and C-families evolving after the A-family. The A-family utilizes two proton input channels to transfer protons for pumping and chemistry, whereas the B- and C-families require only one. Generally, the B- and C-families also have higher apparent oxygen affinities than the A-family. Here we use whole cell proton pumping measurements to demonstrate differential proton pumping efficiencies between representatives of the A-, B-, and C-oxygen reductase families. The A-family has a coupling stoichiometry of 1 H+/e-, whereas the B- and C-families have coupling stoichiometries of 0.5 H+/e-. The differential proton pumping stoichiometries, along with differences in the structures of the proton-conducting channels, place critical constraints on models of the mechanism of proton pumping. Most significantly, it is proposed that the adaptation of aerobic respiration to low oxygen environments resulted in a concomitant reduction in energy conservation efficiency, with important physiological and ecological consequences. PMID:21844375

Han, Huazhi; Hemp, James; Pace, Laura A.; Ouyang, Hanlin; Ganesan, Krithika; Roh, Jung Hyeob; Daldal, Fevzi; Blanke, Steven R.; Gennis, Robert B.

2011-01-01

257

Aerobic biotransformation of polybrominated diphenyl ethers (PBDEs) by bacterial isolates  

PubMed Central

Polybrominated diphenyl ethers (PBDEs) are flame retardants that have been used in consumer products and furniture for three decades. Currently, very little is known about their fate in the environment and specifically about their susceptibility to aerobic biotransformation. Here, we investigated the ability of the polychlorinated biphenyl (PCB) degrading bacteria Rhodococcus jostii RHA1 and Burkholderia xenovorans LB400 to transform mono- through hexa-BDEs at ppb levels. We also tested the PBDE transforming abilities of related strain Rhodococcus sp. RR1 and the ether-degrading Pseudonocardia dioxanivorans CB1190. The two PCB-degrading strains transformed all of the mono- through penta-BDEs and strain LB400 transformed one of the hexa-BDEs. The extent of transformation was inversely proportional to the degree of bromination. Strains RR1 and CB1190 were only able to transform the less brominated mono- and di- BDE congeners. RHA1 released stoichiometric quantities of bromide while transforming mono- and tetra-BDE congeners. LB400 instead converted most of a mono-BDE to a hydroxylated mono-BDE. This is the first report of aerobic transformation of tetra-, penta- and hexa-BDEs as well as the first report of stoichiometric release of bromide during PBDE transformation. PMID:19731666

Robrock, Kristin R.; Coelhan, Mehmet; Sedlak, David; Alvarez-Cohen, Lisa

2009-01-01

258

Survey of petroleum-degrading bacteria in coastal waters of Sunderban Biosphere Reserve  

Microsoft Academic Search

A survey of petroleum-degrading bacteria was carried out in the Indian part of deltaic Sunderbans to evaluate the distribution of the naturally occurring petroleum-degrading aerobic bacteria. Bacteriological analysis of surface water samples collected from five different locations in the Hooghly–Matla river mouth showed that, depending on the location, 0.08–2.0% of the heterotrophic bacteria culturable in marine agar medium could degrade

Subarna Roy; Dipak Hens; Debabrata Biswas; Dipa Biswas; Ranajit Kumar

2002-01-01

259

Phylogenetic profiling of culturable bacteria associated with early phase of mushroom composting assessed by amplified rDNA restriction analysis  

Microsoft Academic Search

The edible mushroom Agaricus bisporus is grown commercially on composted manure\\/straw mixtures. Mushroom composting is a fermentation process in which various\\u000a groups of microorganisms play important roles at different stages of composting. The present study was conducted to explore\\u000a the mesophilic bacterial diversity in the early phase of mushroom composting. Morphologically all the isolated bacteria were\\u000a either Gram-positive rods, cocci

Ajay Veer Singh; Abhinay Sharma; Bhavdish N. Johri

260

Seven N-terminal Residues of a Thermophilic Xylanase Are Sufficient to Confer Hyperthermostability on Its Mesophilic Counterpart  

PubMed Central

Xylanases, and especially thermostable xylanases, are increasingly of interest for the deconstruction of lignocellulosic biomass. In this paper, the termini of a pair of xylanases, mesophilic SoxB and thermophilic TfxA, were studied. Two regions in the N-terminus of TfxA were discovered to be potentially important for the thermostability. By focusing on Region 4, it was demonstrated that only two mutations, N32G and S33P cooperated to improve the thermostability of mesophilic SoxB. By introducing two potential regions into SoxB in combination, the most thermostable mutant, M2-N32G-S33P, was obtained. The M2-N32G-S33P had a melting temperature (Tm) that was 25.6°C higher than the Tm of SoxB. Moreover, M2-N32G-S33P was even three-fold more stable than TfxA and had a Tm value that was 9°C higher than the Tm of TfxA. Thus, for the first time, the mesophilic SoxB “pupil” outperformed its thermophilic TfxA “master” and acquired hyperthermostability simply by introducing seven thermostabilizing residues from the extreme N-terminus of TfxA. This work suggested that mutations in the extreme N-terminus were sufficient for the mesophilic xylanase SoxB to acquire hyperthermostability. PMID:24498158

Zhang, Shan; He, Yongzhi; Yu, Haiying; Dong, Zhiyang

2014-01-01

261

Aerobic thermophilic treatment of farm slurry and food wastes  

Microsoft Academic Search

The review discusses the aerobic treatments for farm slurry and food wastes and concentrates in particular on the thermophilic aerobic treatments. Methods are discussed under the heading of chemical, physical and other treatments. From those methods considered, the most suitable physical–microbiological treatment are aerobic thermophilic treatments. The main problem faced in aerobic thermophilic treatments could be the foaming formation during

Mohammed Mohaibes; Helvi Heinonen-Tanski

2004-01-01

262

Monofermentation of grass silage under mesophilic conditions: measurements and mathematical modeling with ADM 1.  

PubMed

In this paper experimental data from grass fermentation and simulation results with the Anaerobic Digestion Model (ADM) No. 1 are described. Two laboratory reactors were operated under mesophilic conditions with volumetric loading rates in between 0.3 and 2.5 kg(VS)/(m(3) x d). Two different kinds of grass silage were used as substrates, resulting in an average specific biogas production of 600 L/kg(VS). The ADM 1 was calibrated both manually and with the help of a Genetic Algorithm in Matlab/Simulink. Results from calibration indicate that the NH3 inhibition constant used to model the inhibition of acetate uptake is three to five times higher compared with digested activated sludge. The hydrogen inhibition constants applied for propionate and valerate/butyrate uptake are around two orders of magnitude lower than for sludge digestion. PMID:18977132

Wichern, Marc; Gehring, Tito; Fischer, Katrin; Andrade, Diana; Lübken, Manfred; Koch, Konrad; Gronauer, Andreas; Horn, Harald

2009-02-01

263

Column bioleaching of uranium embedded in granite porphyry by a mesophilic acidophilic consortium.  

PubMed

A mesophilic acidophilic consortium was enriched from acid mine drainage samples collected from several uranium mines in China. The performance of the consortium in column bioleaching of low-grade uranium embedded in granite porphyry was investigated. The influences of several chemical parameters on uranium extraction in column reactor were also investigated. A uranium recovery of 96.82% was achieved in 97 days column leaching process including 33 days acid pre-leaching stage and 64 days bioleaching stage. It was reflected that indirect leaching mechanism took precedence over direct. Furthermore, the bacterial community structure was analyzed by using Amplified Ribosomal DNA Restriction Analysis. The results showed that microorganisms on the residual surface were more diverse than that in the solution. Acidithiobacillus ferrooxidans was the dominant species in the solution and Leptospirillum ferriphilum on the residual surface. PMID:21316943

Qiu, Guanzhou; Li, Qian; Yu, Runlan; Sun, Zhanxue; Liu, Yajie; Chen, Miao; Yin, Huaqun; Zhang, Yage; Liang, Yili; Xu, Lingling; Sun, Limin; Liu, Xueduan

2011-04-01

264

High resolution structure of the large ribosomal subunit from a Mesophilic Eubacterium  

SciTech Connect

We describe the high resolution structure of the large ribosomal subunit from Deinococcus radiodurans (D50S), a gram-positive mesophile suitable for binding of antibiotics and functionally relevant ligands. The over-all structure of D50S is similar to that from the archae bacterium Haloarcula marismortui (H50S); however, a detailed comparison revealed significant differences, for example, in the orientation of nucleotides in peptidyl transferase center and in the structures of many ribosomal proteins. Analysis of ribosomal features involved in dynamic aspects of protein biosynthesis that are partially or fully disordered in H50S revealed the conformations of intersubunit bridges in unbound subunits, suggesting how they may change upon subunit association and how movements of the L1-stalk may facilitate the exit of tRNA.

Harms, Joerg; Schluenzen, Frank; Zarivach, Raz; Bashan, Anat; Gat, Sharon; Agmon, Ilana; Bartels, Heike; Franceschi, Francois; Yonath, Ada (Weizmann Inst Israel); (Mac Planck Germany); (Max Planck Germany)

2009-10-07

265

Dry anaerobic digestion of food waste under mesophilic conditions: performance and methanogenic community analysis.  

PubMed

The performance of dry anaerobic digestion (AD) of food waste was investigated under mesophilic conditions and the methanogenic community was investigated using 454 pyrosequencing. Stable dry AD was achieved by hydraulic retention time (HRT) control without the addition of alkali agents. The average CH4 production rate, CH4 content, and volatile solid reduction rate were 2.51±0.17m(3)/m(3)/d, 66±2.1%, and 65.8±1.22%, respectively, at an HRT of 40d. The methanogenic community of the seed sludge experienced a significant reduction in genus diversity from 18 to 4 and a dominant methanogenic shift from hydrogenotrophic to acetoclastic groups after the acclimation under dry condition. Almost all sequences of the dry anaerobic digester were closely related with those of Methanosarcina thermophila with similarity of 96.4-99.1%. The experimental results would serve as useful information to understand the dry AD system. PMID:23347929

Cho, Si-Kyung; Im, Wan-Taek; Kim, Dong-Hoon; Kim, Moon-Hwan; Shin, Hang-Sik; Oh, Sae-Eun

2013-03-01

266

Structures of mesophilic and extremophilic citrate synthases reveal rigidity and flexibility for function.  

PubMed

Citrate synthase (CS) catalyses the entry of carbon into the citric acid cycle and is highly-conserved structurally across the tree of life. Crystal structures of dimeric CSs are known in both "open" and "closed" forms, which differ by a substantial domain motion that closes the substrate-binding clefts. We explore both the static rigidity and the dynamic flexibility of CS structures from mesophilic and extremophilic organisms from all three evolutionary domains. The computational expense of this wide-ranging exploration is kept to a minimum by the use of rigidity analysis and rapid all-atom simulations of flexible motion, combining geometric simulation and elastic network modeling. CS structures from thermophiles display increased structural rigidity compared with the mesophilic enzyme. A CS structure from a psychrophile, stabilized by strong ionic interactions, appears to display likewise increased rigidity in conventional rigidity analysis; however, a novel modified analysis, taking into account the weakening of the hydrophobic effect at low temperatures, shows a more appropriate decreased rigidity. These rigidity variations do not, however, affect the character of the flexible dynamics, which are well conserved across all the structures studied. Simulation trajectories not only duplicate the crystallographically observed symmetric open-to-closed transitions, but also identify motions describing a previously unidentified antisymmetric functional motion. This antisymmetric motion would not be directly observed in crystallography but is revealed as an intrinsic property of the CS structure by modeling of flexible motion. This suggests that the functional motion closing the binding clefts in CS may be independent rather than symmetric and cooperative. PMID:24948467

Wells, Stephen A; Crennell, Susan J; Danson, Michael J

2014-10-01

267

Bacteria and Foodborne Illness  

MedlinePLUS

... Some parasites and chemicals also cause foodborne illnesses. Bacteria Bacteria are tiny organisms that can cause infections of the GI tract. Not all bacteria are harmful to humans. Some harmful bacteria may ...

268

Conditioning and Aerobics for Older Americans.  

ERIC Educational Resources Information Center

A class designed for the maintenance and gradual improvement of senior citizens' physical fitness includes relaxation training, flexibility and stretching exercises, interval training activities (designed as a link between less strenuous exercise and more strenuous activities), and aerobic exercises. (CJ)

Hansen, Joyce

1980-01-01

269

The Energetics of Aerobic versus Anaerobic Respiration.  

ERIC Educational Resources Information Center

Background information, laboratory procedures, and a discussion of the results of an experiment designed to investigate the difference in energy gained from the aerobic and anaerobic oxidation of glucose are presented. Sample experimental and calculated data are included. (CW)

Champion, Timothy D.; Schwenz, Richard W.

1990-01-01

270

Aerobic dynamic feeding as a strategy for in situ accumulation of polyhydroxyalkanoate in aerobic granules.  

PubMed

Aerobic dynamic feeding (ADF) strategy was applied in sequencing batch reactor (SBR) to accumulate polyhydroxyalkanoate (PHA) in aerobic granules. The aerobic granules were able to remove 90% of the COD from palm oil mill effluent (POME). The volatile fatty acids (VFAs) in the POME are the sole source of the PHA accumulation. In this work, 100% removal of propionic and butyric acids in the POME were observed. The highest amount of PHA produced in aerobic granules was 0.6833mgPHA/mgbiomass. The PHA formed was identified as a P (hydroxybutyrate-co-hydroxyvalerate) P (HB-co-HV). PMID:24725384

Gobi, K; Vadivelu, V M

2014-06-01

271

A comparative study on the alternating mesophilic and thermophilic two-stage anaerobic digestion of food waste.  

PubMed

An alternating mesophilic and thermophilic two stage anaerobic digestion (AD) process was conducted. The temperature of the acidogenic (A) and methanogenic (M) reactors was controlled as follows: System 1 (S1) mesophilic A-mesophilic M; (S2) mesophilic A-thermophilic M; and (S3) thermophilic A-mesophilic M. Initially, the AD reactor was acclimatized and inoculated with digester sludge. Food waste was added with the soluble chemical oxygen demand (SCOD) concentrations of 41.4-47.0 g/L and volatile fatty acids of 2.0-3.2 g/L. Based on the results, the highest total chemical oxygen demand removal (86.6%) was recorded in S2 while S3 exhibited the highest SCOD removal (96.6%). Comparing S1 with S2, total solids removal increased by 0.5%; S3 on the other hand decreased by 0.1 % as compared to S1. However, volatile solids (VS) removal in S1, S2, and S3 was 78.5%, 81.7%, and 79.2%, respectively. S2 also exhibited the highest CH4 content, yield, and production rate of 70.7%, 0.44 L CH4/g VSadded, and 1.23 L CH4/(L·day), respectively. Bacterial community structure revealed that the richness, diversity, evenness, and dominance of S2 were high except for the archaeal community. The terminal restriction fragments dendrogram also revealed that the microbial community of the acidogenic and methanogenic reactors in S2 was distinct. Therefore, S2 was the best among the systems for the operation of two-stage AD of food waste in terms of CH4 production, nutrient removal, and microbial community structure. PMID:25079836

Ventura, Jey-R Sabado; Lee, Jehoon; Jahng, Deokjin

2014-06-01

272

Bacterial Diversity and Function of Aerobic Granules Engineered in a Sequencing Batch Reactor for Phenol Degradation  

PubMed Central

Aerobic granules are self-immobilized aggregates of microorganisms and represent a relatively new form of cell immobilization developed for biological wastewater treatment. In this study, both culture-based and culture-independent techniques were used to investigate the bacterial diversity and function in aerobic phenol- degrading granules cultivated in a sequencing batch reactor. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes demonstrated a major shift in the microbial community as the seed sludge developed into granules. Culture isolation and DGGE assays confirmed the dominance of ?-Proteobacteria and high-G+C gram-positive bacteria in the phenol-degrading aerobic granules. Of the 10 phenol-degrading bacterial strains isolated from the granules, strains PG-01, PG-02, and PG-08 possessed 16S rRNA gene sequences that matched the partial sequences of dominant bands in the DGGE fingerprint belonging to the aerobic granules. The numerical dominance of strain PG-01 was confirmed by isolation, DGGE, and in situ hybridization with a strain-specific probe, and key physiological traits possessed by PG-01 that allowed it to outcompete and dominate other microorganisms within the granules were then identified. This strain could be regarded as a functionally dominant strain and may have contributed significantly to phenol degradation in the granules. On the other hand, strain PG-08 had low specific growth rate and low phenol degradation ability but showed a high propensity to autoaggregate. By analyzing the roles played by these two isolates within the aerobic granules, a functional model of the microbial community within the aerobic granules was proposed. This model has important implications for rationalizing the engineering of ecological systems. PMID:15528543

Jiang, He-Long; Tay, Joo-Hwa; Maszenan, Abdul Majid; Tay, Stephen Tiong-Lee

2004-01-01

273

A simple model for diauxic growth of denitrifying bacteria.  

PubMed

A simple model has been formulated to simulate diauxic growth of denitrifying bacteria. It is capable of fitting the experimental results of batch growth experiments with Pseudomonas denitrificans under various conditions. It successfully predicts the observed lags when a pure culture of this bacterium switches from oxygen to nitrate as terminal electron acceptor. The model includes the effect of carbon substrate limitation and length of aerobic phase and does not run into problems when switching from anoxic to aerobic conditions, unlike prior models of diauxic growth. PMID:15899290

Casasśs, Anna I; Hamilton, Ryan K; Svoronos, Spyros A; Koopman, Ben

2005-05-01

274

Subgingival bacteria--comparison of culture results in dogs and cats with gingivitis.  

PubMed

Aerobic and anaerobic subgingival bacteria were cultured and identified from 49 dogs and 40 cats with spontaneous gingivitis. The most common organisms were gram-negative anaerobes (37% of canine isolates and 39% of feline isolates) and gram-positive aerobes (36% of canine isolates and 29% of feline isolates). No major differences were found between the subgingival floras of dogs and cats with gingivitis. PMID:9693642

Harvey, C E; Thornsberry, C; Miller, B R

1995-12-01

275

[Surface layers of methanotrophic bacteria].  

PubMed

Structural and functional characteristics of the regular glycoprotein layers in prokaryotes are analyzed with a special emphasis on aerobic methanotrophic bacteria. S-layers are present at the surfaces of Methylococcus, Methylothermus, and Methylomicrobium cells. Different Methylomicrobium species either synthesize S-layers with planar (p2, p4) symmetry or form cup-shaped or conicalstructures with hexagonal (p6) symmetry. A unique, copper-binding polypeptide 'CorA'/MopE (27/45 kDa), which is coexpressed with the diheme periplasmic cytochrome c peroxidase 'CorB'/Mca (80 kDa) was found in Methylomicrobium album BG8, Methylomicrobium alcaliphilum 20Z, and Methylococcus capsulatus Bath. This tandem of the surface proteins is functionally analogous to a new siderophore, methanobactin. Importantly, no 'CorA'/MopE homologue was found in methanotrophs not forming S-layers. The role of surface proteins in copper metabolism and initial methane oxidation is discussed. PMID:25509389

Khmelenina, V N; Suzina, N E; Trotsenko, Iu A

2013-01-01

276

Aerobic Excercise and Research Opportunities to Benefit Impaired Children. (Project AEROBIC). Final Report.  

ERIC Educational Resources Information Center

The final report summarizes accomplishments of Project AEROBIC (Aerobic Exercise and Research Opportunities to Benefit Impaired Children), which provided a physical education exercise program for severely, profoundly, and multiply handicapped children aged 10-21. Activities are outlined for the 3 year period and include modification of exercise…

Idaho Univ., Moscow.

277

Modelling of the acid base properties of two thermophilic bacteria at different growth times  

NASA Astrophysics Data System (ADS)

Acid-base titrations and electrophoretic mobility measurements were conducted on the thermophilic bacteria Anoxybacillus flavithermus and Geobacillus stearothermophilus at two different growth times corresponding to exponential and stationary/death phase. The data showed significant differences between the two investigated growth times for both bacterial species. In stationary/death phase samples, cells were disrupted and their buffering capacity was lower than that of exponential phase cells. For G. stearothermophilus the electrophoretic mobility profiles changed dramatically. Chemical equilibrium models were developed to simultaneously describe the data from the titrations and the electrophoretic mobility measurements. A simple approach was developed to determine confidence intervals for the overall variance between the model and the experimental data, in order to identify statistically significant changes in model fit and thereby select the simplest model that was able to adequately describe each data set. Exponential phase cells of the investigated thermophiles had a higher total site concentration than the average found for mesophilic bacteria (based on a previously published generalised model for the acid-base behaviour of mesophiles), whereas the opposite was true for cells in stationary/death phase. The results of this study indicate that growth phase is an important parameter that can affect ion binding by bacteria, that growth phase should be considered when developing or employing chemical models for bacteria-bearing systems.

Heinrich, Hannah T. M.; Bremer, Phil J.; McQuillan, A. James; Daughney, Christopher J.

2008-09-01

278

Corn silage management: effects of maturity, inoculation, and mechanical processing on pack density and aerobic stability.  

PubMed

Three experiments were conducted to evaluate the effects of inoculation, maturity, and mechanical processing of corn silage on aerobic stability and pack density. Corn silage was stored in 20-L mini silos for the three aerobic stability experiments. Corn silage was stored in 80-L mini silos for the three pack-density experiments. The wet pack density of corn silage tended to decrease as maturity advanced in all of the pack-density experiments, and processed corn silage had a greater wet pack density compared with unprocessed corn silage in two of the three 20-L mini silo experiments. Aerobic stability, measured as the number of hours to reach 1.7 degrees C above ambient, was greater for processed corn silage in two of the three 20-L mini silo experiments, and was greater for inoculated corn silage across the three 20-L mini silo experiments. Inoculation of corn silage with lactic acid producing bacteria tended to improve aerobic stability of corn silage more than maturity and mechanical processing. PMID:11913704

Johnson, L M; Harrison, J H; Davidson, D; Mahanna, W C; Shinners, K; Linder, D

2002-02-01

279

Nitrate?reducing and ammonium?oxidizing bacteria in the vadose zone of the chalk aquifer of England  

Microsoft Academic Search

The vadose zone of the Chalk aquifer from two sites of different land use was found to contain large numbers of nitrate?reducing and ammonium?oxidizing bacteria. Relationships between the type of bacteria and nitrogen compounds produced showed that denitrification was occurring beneath the permanent grassland site, whereas the vadose zone beneath the fertilized arable site was essentially aerobic and little attenuation

K. Whitelaw; J. F. Rees

1980-01-01

280

Comparison of the SimPlate total plate count method with Petrifilm, Redigel, conventional pour-plate methods for enumerating aerobic microorganisms in foods.  

PubMed

The SimPlate Total Plate Count (TPC) method, developed by IDEXX Laboratories, Inc., is designed to determine the most probable number of aerobic microorganisms in foods. The 24-h test was compared to the conventional plate count agar (PCA) method, the Petrifilm Aerobic Count plates, and the Redigel Total Count procedure for enumerating microflora in 751 food samples. Results using the SimPlate TPC method were highly correlated (r > or = 0.96) with results from other test methods. Slopes (0.96-0.97) were not significantly different from 1, and y intercepts (-0.03-0.08) were not different from O. The SimPlate has a high counting range (> 1600 most probable number per single dilution), thus requiring fewer dilutions of samples compared to other methods evaluated. Some foods, e.g., raw liver, wheat flour, and nuts, contain enzymes that gave false-positive reactions on SimPlates. Overall, however, the SimPlate TPC method is a suitable alternative to conventional PCA, Petrifilm, and Redigel methods for estimating populations of mesophilic aerobic microorganisms in a wide range of foods. PMID:9708246

Beuchat, L R; Copeland, F; Curiale, M S; Danisavich, T; Gangar, V; King, B W; Lawlis, T L; Likin, R O; Okwusoa, J; Smith, C F; Townsend, D E

1998-01-01

281

Bosea minatitlanensis sp. nov., a strictly aerobic bacterium isolated from an anaerobic digester.  

PubMed

A strictly aerobic, mesophilic bacterium, strain AMX 51(T), was isolated from anaerobic digester sludge. Cells were Gram-negative, motile, non-sporulating, straight to curved rods with one polar flagellum. The isolate had phenotypic traits of the genus Bosea, including cellular fatty acid and substrate utilization profiles. Physiological characteristics and antibiotic susceptibility were determined. Phylogenetic analysis revealed that strain AMX 51(T) was a member of the alpha-Proteobacteria, most closely related to Bosea thiooxidans DSM 9653(T) (similarity of 98.88 %). Methylobacterium organophilum JCM 2833(T), Methylobacterium mesophilicum JCM 2829(T), Afipia clevelandensis DSM 7315(T), Afipia felis DSM 7326(T), Afipia broomeae DSM 7327(T), Blastobacter denitrificans LMG 8443(T) and Bradyrhizobium japonicum DSM 30131(T) showed significant 16S rRNA gene sequence similarities to strain AMX 51(T). The DNA G+C composition of strain AMX 51(T) was 68.5 mol%. DNA-DNA hybridization analysis revealed 44.2 and 15.1 % relatedness between strain AMX 51(T) and the respective type strains of Bosea thiooxidans and A. felis. Overall results suggest that strain AMX 51(T) (=DSM 13099(T)=ATCC 700918(T)=CIP 106457(T)) represents a novel species of the genus Bosea; the name Bosea minatitlanensis sp. nov. is proposed. PMID:13130002

Ouattara, Aboubakar S; Assih, Essokazi A; Thierry, Sébastien; Cayol, Jean-Luc; Labat, Marc; Monroy, Oscar; Macarie, Hervé

2003-09-01

282

Evaluation of performance in a combined UASB and aerobic contact oxidation process treating acrylic wastewater.  

PubMed

The lab-scale and full-scale performance of a combined mesophilic up-flow anaerobic sludge blanket (UASB) and aerobic contact oxidation (ACO) process for treating acrylic wastewater was studied. During lab-scale experiment, the overwhelmed volumetric load for UASB was above 6?kg chemical oxygen demand (COD) ·(m(-3)·d(-1)) since COD removal efficiency dropped dramatically from 73% at 6?kg COD·(m(-3)·d(-1)) to 61% at 7?kg COD·(m(-3)·d(-1)) and 53% at 8?kg COD·(m(-3)·d(-1)). Further results showed that an up-flow fluid velocity of 0.5?m?h(-1) for UASB obtained a highest COD removal efficiency of 75%, and the optimum COD volumetric load for the corresponding ACO was 1.00?kg COD·(m(-3)·d(-1)). Based on the configuration of the lab-scale experiment, a full-scale application with an acrylic wastewater treatment capacity of 8?m(3)?h(-1) was constructed and operated at a volumetric load of 5.5?kg COD·(m(-3)·d(-1)), an up-flow fluid velocity of 0.5?m?h(-1) for UASB and a volumetric load of 0.9?kg COD·(m(-3)·d(-1)) for ACO; and the final effluent COD was around 740?mg?L(-1). The results suggest that a combined UASB-ACO process is promising for treating acrylic wastewater. PMID:25204720

Li, Anfeng; Dong, Na; He, Manni; Pan, Tao

2015-04-01

283

[Short-cut nitrification of landfill leachate by aerobic moving-bed biofilm reactor].  

PubMed

Short-cut nitrification process was studied to remove the ammonium nitrogen from the anaerobically pretreated leachate using aerobic moving-bed biofilm reactor (MBBR) at ambient temperature. The effect of DO concentration, pH and C/N ratio on the ammonium removal efficiency and nitrite accumulation rate was investigated, respectively. Experimental results showed that, more than 70% of ammonium removal efficiency and about 90% of nitrite accumulation rate could be achieved when the reaction conditions were controlled as follows: HRT at 24 hours, DO concentration at 2 mg x L(-1), pH at 8 and C/N ratio less than 3. Batch experiments showed that the quantity and activity of ammonia oxidizing bacteria were much higher than those of nitrite oxidizing bacteria. MBBR could effectively remove ammonium nitrogen from leachate and easily obtain a stable nitrite accumulation rate due to the selective immobilization and accumulation of ammonia oxidizing bacteria on the bio-carrier. PMID:17633176

Du, Yue; Chen, Sheng; Sun, De-zhi

2007-05-01

284

Microbiological quality of freshwater prawns during storage  

Microsoft Academic Search

Microbiological quality analysis of freshwater prawns from three sampling sites in Peninsular Malaysia viz: Site 1- Kg. Jumbang, Negri Sembilan; Site 2- Kg. Cangkat Tin, Perak and Site 3- Kg. Cenderiang, Perak for total mesophilic and psychrophilic aerobic counts, proteolytic bacterial counts, histamine producing bacteria, cadaverine producing bacteria and putrescine producing bacteria in the prawns and pond water for the

Abu Bakar; M. Basri

2008-01-01

285

Anaerobic biodegradation of explosives and related compounds by sulfate-reducing and methanogenic bacteria : a review.  

SciTech Connect

In recent years, research on microbial degradation of explosives and nitroaromatic compounds has increased. Most studies of the microbial metabolism of nitroaromatic compounds have used aerobic microorganisms. Ecological observations suggest that sulfate-reducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Few review papers exist, and those deal mainly with aerobic bacterial degradation of explosives; none deals with anaerobic bacteria. In this paper, we review the anaerobic metabolic processes in the degradation of explosives and nitroaromatic compounds under sulfate-reducing and methanogenic conditions.

Boopathy, R.; Kulpa, C. F.; Manning, J.; Environmental Research; Univ. of Notre Dame

1998-01-01

286

Occurrence and reactivation of viable but non-culturable E. coli in sewage sludge after mesophilic and thermophilic anaerobic digestion.  

PubMed

The occurrence and reactivation of viable but non-culturable (VBNC) Escherichia coli after different anaerobic digestions and the subsequent dewatering and storage were evaluated and compared. Culturable E. coli in digested sludge increased by two to four orders of magnitudes immediately after dewatering. However, counts of both the total and viable E. coli indicated that the increase of E. coli was attributed to its reactivation from the VBNC state to the culturable state. The VBNC pathogen incidences of thermophilic digestion were two to three orders of magnitude higher than those of mesophilic digestion. Accordingly, culturable E. coli in thermophilic, digested sludge after storage were one order of magnitude higher than mesophilic digestion. Anaerobic digestion thus mainly alters the culturable state of pathogens rather than killing them; therefore the biological safety of digested sludge, especially temperature-phased anaerobic digestion, should be carefully assessed. PMID:24101245

Fu, Bo; Jiang, Qian; Liu, Hongbo; Liu, He

2014-02-01

287

Novel genes for nitrite reductase and Amo-related proteins indicate a role of uncultivated mesophilic crenarchaeota in nitrogen cycling  

Microsoft Academic Search

Summary Mesophilic crenarchaeota are frequently found in ter- restrial and marine habitats worldwide, but despite their considerable abundance the physiology of these as yet uncultivated archaea has remained unknown. From a 1.2 Gb large-insert environmental fosmid library of a calcareous grassland soil, a 43 kb genomic fragment was isolated with a ribosomal RNA that shows its affiliation to group 1.1b

Alexander H. Treusch; Sven Leininger; Arnulf Kletzin; Stephan C. Schuster; Christa Schleper

2005-01-01

288

Denitrification and nitric oxide reduction in an aerobic toluene-treating biofilter  

SciTech Connect

The presence of significant denitrification activity in an aerobic toluene-treating biofilter was demonstrated under batch and flow-through conditions. N{sub 2}O concentrations of 9.2 ppm{sub v} were produced by denitrifying bacteria in the presence of 15% acetylene, in a flow-through system with a bulk gas phase O{sub 2} concentration of >17%. The carbon source for denitrification was not toluene but a byproduct or metabolite of toluene catabolism. Denitrification conditions were successfully used for the reduction of 60 ppm{sub v} nitric oxide to 15 ppm{sub v} at a flow rate of 3 L/min (EBRT of 3 min) in a fully aerated, 17%/v/v O{sub 2} (superficially aerobic) biofilter. Higher NO removal efficiency (97%) was obtained by increasing the toluene supply to the biofilter.

Plessis, C.A. du; Kinney, K.A.; Schroeder, E.D.; Chang, D.P.Y.; Scow, K.M. [Univ. of California, Davis, CA (United States)] [Univ. of California, Davis, CA (United States)

1998-05-20

289

Comparative performance between temperature-phased and conventional mesophilic two-phased processes in terms of anaerobically produced bioenergy from food waste.  

PubMed

Comparative evaluation of bioenergy production from food waste was carried out with both a temperature-phased and a conventional mesophilic two-phased process at different organic loading rates (OLRs). No methane was detected in the temperature-phased thermophilic-acidogenic fermenter at all the OLRs tested. However, a significant amount of methane content was detected in the conventional two-phased mesophilic-acidogenic fermenter, with increments depending on the organic loading rate [from 17% at 3 g VS L(-1) day(-1) to 25% at 8 g VS L(-1) day(-1) (VS, volatile solid)]. Acetate and butyrate were the main volatile fatty acids (VFAs) in the temperature-phased thermophilic-acidogenic fermenter; conversely propionate was a major VFA in the conventional two-phased mesophilic-acidogenic fermenter. Through the chemical oxygen demand (COD) balance of both temperature-phased and conventional mesophilic two-phased processes, the fraction of the feed-COD converted to the hydrogen-COD in the thermophilic-acidogenic fermenter within the former process was estimated from 7.9 to 9.3%, with a peak at ORL of 6 g VS L(-1) day(-1), whereas it was quantified from 0.3 to 0.9% in the mesophilic-acidogenic fermenter within the latter one. Moreover, the fraction of the feed-COD converted to the methane-COD in the mesophilic-acidogenic fermenter within the conventional two-phased process ranged from 5.4 to 7.9%. On the other hand, conversion of the feed-COD to the methane-COD in the mesophilic-methanogenic fermenter of both temperature-phased and conventional mesophilic two-phased processes ranged from 66.2 to 72.3% and from 63.5 to 70.5%, respectively, with decrements related to the increase of organic loading rate. PMID:15751393

Youn, Jong-Ho; Shin, Hang-Sik

2005-02-01

290

Mesophilic and Thermophilic Conditions Select for Unique but Highly Parallel Microbial Communities to Perform Carboxylate Platform Biomass Conversion  

PubMed Central

The carboxylate platform is a flexible, cost-effective means of converting lignocellulosic materials into chemicals and liquid fuels. Although the platform's chemistry and engineering are well studied, relatively little is known about the mixed microbial communities underlying its conversion processes. In this study, we examined the metagenomes of two actively fermenting platform communities incubated under contrasting temperature conditions (mesophilic 40°C; thermophilic 55°C), but utilizing the same inoculum and lignocellulosic feedstock. Community composition segregated by temperature. The thermophilic community harbored genes affiliated with Clostridia, Bacilli, and a Thermoanaerobacterium sp, whereas the mesophilic community metagenome was composed of genes affiliated with other Clostridia and Bacilli, Bacteriodia, ?-Proteobacteria, and Actinobacteria. Although both communities were able to metabolize cellulosic materials and shared many core functions, significant differences were detected with respect to the abundances of multiple Pfams, COGs, and enzyme families. The mesophilic metagenome was enriched in genes related to the degradation of arabinose and other hemicellulose-derived oligosaccharides, and the production of valerate and caproate. In contrast, the thermophilic community was enriched in genes related to the uptake of cellobiose and the transfer of genetic material. Functions assigned to taxonomic bins indicated that multiple community members at either temperature had the potential to degrade cellulose, cellobiose, or xylose and produce acetate, ethanol, and propionate. The results of this study suggest that both metabolic flexibility and functional redundancy contribute to the platform's ability to process lignocellulosic substrates and are likely to provide a degree of stability to the platform's fermentation processes. PMID:22761870

Hollister, Emily B.; Forrest, Andrea K.; Wilkinson, Heather H.; Ebbole, Daniel J.; Tringe, Susannah G.; Malfatti, Stephanie A.; Holtzapple, Mark T.; Gentry, Terry J.

2012-01-01

291

Mesophilic anaerobic digestion with high-temperature microwave pretreatment and importance of inoculum acclimation.  

PubMed

Thickened waste activated sludge (TWAS) was pretreated with microwave irradiation to temperatures higher than the boiling point (between 110 and 175 degrees C) using different microwave intensities. Biochemical methane potential (BMP) assays demonstrated that, although mesophilic anaerobic digestion (MAD) inoculum used was acclimated for 4 months with microwave pretreated TWAS (to 175 degrees C), acute methanogenic inhibition was observed. Additionally, the microwave conditions applied increased the soluble chemical oxygen demand (sCOD)-to-total COD (tCOD) ratio; however, no significant enhancement in the rate or extent of TWAS stabilization was observed for the microwave-pretreated samples. Microwave pretreatment to between 110 and 175 degrees C at lower microwave intensity with a better acclimated MAD inoculum (acclimatized for an additional 3 months) resulted in minimal methanogenic inhibition (improved acclimation) and improved the rate and extent of TWAS biodegradation, as determined by volatile solids removal and biogas production (microwave applied at lower microwave intensity). The TWAS pretreated to 175 degrees C produced 31 +/- 6% more biogas than the control (raw TWAS) by the 18th day of the BMP test, whereas the highest improvement observed from the first set of BMP experiments was 13 +/- 1%. PMID:21751714

Toreci, Isil; Droste, Ronald L; Kennedy, Kevin J

2011-06-01

292

Mesophilic Actinomycetes in the natural and reconstructed sand dune vegetation zones of Fraser Island, Australia.  

PubMed

The natural coastal habitat of Fraser Island located in the State of Queensland, Australia, has been disturbed in the past for mining of the mineral sand ilmenite. Currently, there is no information available on whether these past mining disturbances have affected the distribution, diversity, and survival of beneficial soil microorganisms in the sand dunes of the island. This in turn could deleteriously affect the success of the natural regeneration, plant growth, and establishment on the sand dunes. To support ongoing restoration efforts at sites like these mesophilic actinomycetes were isolated using conventional techniques, with particular emphasis on the taxa previously reported to produce plant-growth-promoting substances and providing support to mycorrhizal fungi, were studied at disturbed sites and compared with natural sites. In the natural sites, foredunes contained higher densities of micromonosporae replaced by increasing numbers of streptomycete species in the successional dune and finally leading to complex actinomycete communities in the mature hind dunes. Whereas in the disturbed zones affected by previous mining activities, which are currently being rehabilitated, no culturable actinomycete communities were detected. These findings suggest that the paucity of beneficial microflora in the rehabilitated sand dunes may be limiting the successful colonization by pioneer plant species. Failure to establish a cover of plant species would result in the mature hind dune plants being exposed to harsh salt and climatic conditions. This could exacerbate the incidence of wind erosion, resulting in the destabilization of well-defined and vegetated successional dunal zones. PMID:17578635

Kurtböke, D I; Neller, R J; Bellgard, S E

2007-08-01

293

Effect of chitosan on UASB treating POME during a transition from mesophilic to thermophilic conditions.  

PubMed

The effects of chitosan addition on treatment of palm oil mill effluent were investigated using two lab-scale upflow anaerobic sludge bed (UASB) reactors: (1) with chitosan addition at the dosage of 2 mg chitosan per g volatile suspended solids on the first day of the operation (R1), (2) without chitosan addition (the control, R2). The reactors were inoculated with mesophilic anaerobic sludge which was acclimatized to a thermophilic condition with a stepwise temperature increase of 5 °C from 37 to 57 °C. The OLR ranged from 2.23 to 9.47 kg COD m(-3) day(-1). The difference in biogas production rate increased from non-significant to 18% different. The effluent volatile suspended solids of R1 was 65 mg l(-1) lower than that of R2 on Day 123. 16S rRNA targeted denaturing gradient gel electrophoresis (DGGE) fingerprints of microbial community indicated that some methanogens in the genus Methanosaeta can be detected in R1 but not in R2. PMID:21316949

Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn

2011-04-01

294

Mesotoga prima gen. nov., sp. nov., the first described mesophilic species of the Thermotogales.  

PubMed

A novel mesophilic member of the Thermotogales, strain MesG1.Ag.4.2, was isolated from sediments from Baltimore Harbor, MD, USA. The strain grew optimally at 37 °C with a doubling time of 16.5 h on xylose. Carbohydrates and proteinaceous compounds supported growth and pentoses were preferred over hexoses. The strain was strictly anaerobic and growth was slightly stimulated by thiosulfate, sulfite, and elemental sulfur. The G + C content of its genomic DNA was 45.3 mol%. Strain MesG1.Ag.4.2 and Kosmotoga olearia lipids were analyzed. Strain MesG1.Ag.4.2 contained no long-chain dicarboxylic acids and its major phospholipid was lyso-phosphatidylserine. Long-chain dicarboxylic acids were found in K. olearia and its major phospholipid was cardiolipin, a lipid not yet reported in Thermotogales species. Phylogenetic analyses of its two 16S rRNA genes placed strain MesG1.Ag.4.2 within the bacterial order Thermotogales. Based on the phylogenetic analyses and its low optimal growth temperature, it is proposed that the strain represents a novel species of a new genus within the family Thermotogaceae, order Thermotogales. The name Mesotoga prima gen. nov., sp. nov. is proposed. The type strain of M. prima is MesG1.Ag.4.2 (= DSM 24739 = ATCC BAA-2239). PMID:22411358

Nesbų, Camilla L; Bradnan, Danielle M; Adebusuyi, Abigail; Dlutek, Marlena; Petrus, Amanda K; Foght, Julia; Doolittle, W Ford; Noll, Kenneth M

2012-05-01

295

Treatment of spent wash in anaerobic mesophilic suspended growth reactor (AMSGR).  

PubMed

Approximately 400 KL of spent wash or vinasse per annum is generated at an average COD concentration of 100,000 mg/l, by over 250 distilleries in India. There is an urgent need to develop, assess and use ecofriendly methods for the disposal of this high strength wastewater. Therefore, an attempt was made to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 L laboratory scale anaerobic mesophilic suspended growth reactor. After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 16.9 L at an Organic Loading Rate (OLR) of 38 g COD/L. A 500% increase in the Volatile Fatty Acid (VFA) concentration (2150 mg/L) was observed, when the OLR was increased from 38 to 39 g COD/L. During the souring phase the removal of COD, Total Solids (TS) and Volatile Solids (VS) were in the order of 52%, 40% and 46% respectively. The methane content in the biogas varied from 65% to 75%. PMID:16850887

Banu, J Rajesh; Kaliappan, S; Rajkumar, M; Beck, Dieter

2006-01-01

296

Aerobic stability and in vitro fiber digestibility of microbially inoculated corn and sorghum silages.  

PubMed

Silage deteriorates readily when exposed to air, resulting in DM losses. Inoculation of silage with lactic acid bacteria may aid fermentation, but effects on aerobic stability are unclear. Two experiments were conducted to determine the effect of commercial bacterial inoculants on aerobic stability and in vitro fiber digestibility of silage. Corn (Zea mays L.; Exp. 1) or sorghum (Sorghum bicolor [L.] Moench; Exp. 2) forage (30% DM) was inoculated (1.1 x 10(5) colony forming units/g of fresh forage) with lactic acid bacteria (Pioneer brand 1174 on corn, Pioneer brand 1129 on sorghum) or bacterial inoculant plus an antifungal agent (potassium sorbate at .5 mg/g of fresh forage) and ensiled in 19-L microsilos. Corn was ensiled for 40 or 186 d and sorghum was ensiled for 30 or 160 d (five microsilos per treatment per ensiling time combination). Silages were exposed to air for 7 to 9 d after opening, and temperature was monitored daily. Water-soluble carbohydrates, pH, NDF, ADF, and in vitro digestibility of NDF and ADF were determined before and after ensiling and on exposed silages. Inoculation reduced (P < .05) silage pH in both corn and sorghum but did not prevent aerobic deterioration of the silages. Temperatures during aerobic exposure of silages did not differ (P > .05) between uninoculated and inoculated silages. Inoculant treatment did not affect (P > .05) concentrations or digestibility of NDF in corn; however, NDF and ADF concentration and in vitro digestibility of NDF increased (P < .05) with time of ensiling in sorghum silage, and in vitro ADF digestibility increased (P < .05) with time of ensiling in corn silage. PMID:8382675

Sanderson, M A

1993-02-01

297

Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes  

NASA Astrophysics Data System (ADS)

Life evolved and flourished in the absence of molecular oxygen (O2). As the O2 content of the atmosphere rose to the present level of 21% beginning about two billion years ago, anaerobic metabolism was gradually supplanted by aerobic metabolism. Anaerobic environments have persisted on Earth despite the transformation to an oxidized state because of the combined influence of water and organic matter. Molecular oxygen diffuses about 104 times more slowly through water than air, and organic matter supports a large biotic O2 demand that consumes the supply faster than it is replaced by diffusion. Such conditions exist in wetlands, rivers, estuaries, coastal marine sediments, aquifers, anoxic water columns, sewage digesters, landfills, the intestinal tracts of animals, and the rumen of herbivores. Anaerobic microsites are also embedded in oxic environments such as upland soils and marine water columns. Appreciable rates of aerobic respiration are restricted to areas that are in direct contact with air or those inhabited by organisms that produce O2.Rising atmospheric O2 reduced the global area of anaerobic habitat, but enhanced the overall rate of anaerobic metabolism (at least on an area basis) by increasing the supply of electron donors and acceptors. Organic carbon production increased dramatically, as did oxidized forms of nitrogen, manganese, iron, sulfur, and many other elements. In contemporary anaerobic ecosystems, nearly all of the reducing power is derived from photosynthesis, and most of it eventually returns to O2, the most electronegative electron acceptor that is abundant. This photosynthetically driven redox gradient has been thoroughly exploited by aerobic and anaerobic microorganisms for metabolism. The same is true of hydrothermal vents (Tunnicliffe, 1992) and some deep subsurface environments ( Chapelle et al., 2002), where thermal energy is the ultimate source of the reducing power.Although anaerobic habitats are currently a small fraction of Earth's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

2003-12-01

298

Enrichment and Characterization of an Autotrophic Ammonia-Oxidizing Archaeon of Mesophilic Crenarchaeal Group I.1a from an Agricultural Soil?†  

PubMed Central

Soil nitrification is an important process for agricultural productivity and environmental pollution. Though one cultivated representative of ammonia-oxidizing Archaea from soil has been described, additional representatives warrant characterization. We describe an ammonia-oxidizing archaeon (strain MY1) in a highly enriched culture derived from agricultural soil. Fluorescence in situ hybridization microscopy showed that, after 2 years of enrichment, the culture was composed of >90% archaeal cells. Clone libraries of both 16S rRNA and archaeal amoA genes featured a single sequence each. No bacterial amoA genes could be detected by PCR. A [13C]bicarbonate assimilation assay showed stoichiometric incorporation of 13C into Archaea-specific glycerol dialkyl glycerol tetraethers. Strain MY1 falls phylogenetically within crenarchaeal group I.1a; sequence comparisons to “Candidatus Nitrosopumilus maritimus” revealed 96.9% 16S rRNA and 89.2% amoA gene similarities. Completed growth assays showed strain MY1 to be chemoautotrophic, mesophilic (optimum at 25°C), neutrophilic (optimum at pH 6.5 to 7.0), and nonhalophilic (optimum at 0.2 to 0.4% salinity). Kinetic respirometry assays showed that strain MY1's affinities for ammonia and oxygen were much higher than those of ammonia-oxidizing bacteria (AOB). The yield of the greenhouse gas N2O in the strain MY1 culture was lower but comparable to that of soil AOB. We propose that this new soil ammonia-oxidizing archaeon be designated “Candidatus Nitrosoarchaeum koreensis.” PMID:22003023

Jung, Man-Young; Park, Soo-Je; Min, Deullae; Kim, Jin-Seog; Rijpstra, W. Irene C.; Sinninghe Damsté, Jaap S.; Kim, Geun-Joong; Madsen, Eugene L.; Rhee, Sung-Keun

2011-01-01

299

Tracing organic compounds in aerobically altered methane-derived carbonate pipes (Gulf of Cadiz, SW Iberia)  

NASA Astrophysics Data System (ADS)

The primary geochemical process at methane seeps is anaerobic oxidation of methane (AOM), performed by methanotrophic archaea and sulfate-reducing bacteria (SRB). The molecular fingerprints (biomarkers) of these chemosynthetic microorganisms can be preserved in carbonates formed through AOM. However, thermal maturity and aerobic degradation can change the original preserved compounds, making it difficult to establish the relation between AOM and carbonate precipitation. Here we report a study of amino acid and lipid abundances in carbonate matrices of aerobically altered pipes recovered from the seafloor of the Gulf of Cadiz (SW Iberian Peninsula). This area is characterized by a complex tectonic regime that supports numerous cold seeps. Studies so far have not determined whether the precipitation of carbonate pipes in the Gulf of Cadiz is a purely chemical process or whether microbial communities are involved. Samples from this site show signs of exposure to oxygenated waters and of aerobic alteration, such as oxidation of authigenic iron sulfides. In addition, the degradation index, calculated from the relative abundance of preserved amino acids, indicates aerobic degradation of organic matter. Although crocetane was the only lipid identified from methanotrophic archaea, the organic compounds detected (n-alkanes, regular isoprenoids and alcohols) are compatible with an origin from AOM coupled with bacterial sulfate reduction (BSR) and subsequent aerobic degradation. We establish a relation among AOM, BSR and pipe formation in the Gulf of Cadiz through three types of analysis: (1) stable carbon and oxygen isotopic composition of carbonate minerals; (2) carbonate microfabrics; and (3) mineralogical composition. Our results suggest that carbonate pipes may form through a process similar to the precipitation of vast amounts of carbonate pavements often found at cold seeps. Our approach suggests that some organic compound patterns, in combination with additional evidence of AOM and BSR, may help indicate the source of altered methane-derived carbonates commonly occurring in ancient and modern deposits.

Merinero, Raśl; Ruiz-Bermejo, Marta; Menor-Salvįn, César; Lunar, Rosario; Martķnez-Frķas, Jesśs

2012-07-01

300

The Lomagundi Event Marks Post-Pasteur Point Evolution of Aerobic Respiration: A Hypothesis  

NASA Astrophysics Data System (ADS)

All published early Earth carbon cycle models assume that aerobic respiration is as ancient as oxygenic photosynthesis. However, aerobic respiration shuts down at oxygen concentrations below the Pasteur Point, (.01 of the present atmospheric level, PAL). As geochemical processes are unable to produce even local oxygen concentrations above .001 PAL, it follows that aerobic respiration could only have evolved after oxygenic photosynthesis, implying a time gap. The evolution of oxygen reductase-utilizing metabolisms presumably would have occupied this interval. During this time the PS-II-generated free oxygen would have been largely unavailable for remineralization of dissolved organic carbon and so would have profoundly shifted the burial ratio of organic/inorganic carbon. We argue that the sequential geological record of the Makganyene (Snowball?) glaciation (2.3-2.22), the exessively aerobic Hekpoort and coeval paleosols, the Lomagundi-Jatuli carbon isotopic excursion (ending 2.056 Ga), and the deposition of concentrated, sedimentary organic carbon (shungite) mark this period of a profoundly unbalanced global carbon cycle. The Kopp et al. (2005) model for oxyatmoversion agrees with phylogenetic evidence for the radiation of cyanobacteria followed closely by the radiation of gram-negative lineages containing magnetotactic bacteria, which depend upon vertical oxygen gradients. These organisms include delta-Proteobacteria from which the mitochondrial ancestor originated. The Precambrian carbon cycle was rebalanced after a series of biological innovations allowed utilization of the high redox potential of free oxygen. Aerobic respiration in mitochondria required the evolution of a unique family of Fe-Cu oxidases, one of many factors contributing to the >210 Myr delay between the Makganyene deglaciation and the end of the Lomagundi-Jatuli event. We speculate that metalliferious fluids associated with the eruption of the Bushveld complex facilitated evolution of these proteins, allowing mitochondrial endosymbiosis and ending the Lomagundi-Jatuli event at 2.056 Ga.

Raub, T. D.; Kirschvink, J. L.; Nash, C. Z.; Raub, T. M.; Kopp, R. E.; Hilburn, I. A.

2009-05-01

301

Growth, natural relationships, cellular fatty acids and metabolic adaptation of sulfate-reducing bacteria that utilize long-chain alkanes under anoxic conditions  

Microsoft Academic Search

Natural relationships, improvement of anaerobic growth on hydrocarbons, and properties that may provide clues to an understanding\\u000a of oxygen-independent alkane metabolism were studied with two mesophilic sulfate-reducing bacteria, strains Hxd3 and Pnd3.\\u000a Strain Hxd3 had been formerly isolated from an oil tank; strain Pnd3 was isolated from marine sediment. Strains Hxd3 and Pnd3\\u000a grew under strictly anoxic conditions on n-alkanes

Frank Aeckersberg; Fred A. Rainey; Friedrich Widdel

1998-01-01

302

Influence of hydraulic retention time on partial nitrification of continuous-flow aerobic granular-sludge reactor.  

PubMed

This study investigated the effects of hydraulic retention time (HRT) at 12 h, 7.2 h and 2.4 h on partial nitrification efficiency of continuous-flow aerobic granular reactors (CFAGRs) with mature aerobic granules (500 +/- 20mg l-1). At HRT 12 h and 7.2h, the removal efficiency of both ammonia-nitrogen (NH4+ - N) and nitrite accumulation rate were exceeding 90%. At HRT 2.4 h, NH4+ - N removal efficiency was reduced but most of the conversion efficiency to nitrite was only slightly reduced. At HRT < 2.4 h, washout of aerobic granules occurred. In all tests conducted herein, the chemical oxygen demand removal efficiencies exceeded 90%. The clone library results noted the presence of ammonia-oxidizing bacteria belonged to beta-Proteobacteria subclass, including 94% of Nitrosomonas europaea and 6% of Nitrosomonas sp. The polymerase chain reaction and denaturing gradient gel electrophoresis results suggested that Alpha proteobacterium, Pseudoxanthomonas mexicana strain, Sphaerotilus natans and Uncultured gamma proteobacterium were responsible for the aerobic granular stability and processing performance. The present CFAGR successfully implemented continuous partial nitrification using aerobic granules at low HRT. PMID:24956768

Wan, Chunli; Yang, Xue; Lee, Duu-Jong; Sun, Supu; Liu, Xiang; Zhang, Peng

2014-08-01

303

Monitoring of growth and physiological activities of biofilm during succession on polystyrene from activated sludge under aerobic and anaerobic conditions.  

PubMed

The present research work monitored the successive biofilm development and its catabolic role in the degradation of polystyrene (PS). PS material was artificially colonized with biofilm by incubating it with activated sludge under aerobic and anaerobic conditions. Biofilm formation was monitored by gravimetric weight analysis, spectrophotometric absorbance technique, heterotrophic plate count, and scanning electron microscopy under aerobic and anaerobic conditions. The wet weight (1.59 and 1.17 g) and dry weight (0.41 and 0.08 g) of a biofilm showed a significant constant increase under aerobic and anaerobic conditions, respectively, from first till 9 weeks of incubation. Plate count of the selected bacteria (Escherichia coli, Salmonella typhimurium, Shigella dysenteriae, Pseudomonas aeruginosa) considerably declined (90-99 %) in the biofilm after seventh and fifth weeks of incubation under aerobic and anaerobic conditions, respectively, indicating a positive shift from pathogenic to beneficial microbial community. While most probable number index of fecal coliforms and E. coli in the sludge showed more reduction (98 and 99 %) under aerobic as compare to anaerobic conditions (86 and 91 %) after 9 weeks of biofilm formation on PS cubes. Correspondingly, the decreasing levels of chemical oxygen demand and biochemical oxygen demand (up to 73 %) showed signs of sludge digestion. Scanning electron microscope coupled with energy dispersive X-ray spectroscope revealed nature of PS media containing high carbon content. However, biofilm development proved to be involved in the biochemical transformation of the PS medium as indicated by Fourier transform infrared spectroscopy. PMID:23361646

Naz, Iffat; Batool, Syeda Ain-ul; Ali, Naeem; Khatoon, Nazia; Atiq, Niama; Hameed, Abdul; Ahmed, Safia

2013-08-01

304

Effects of hexavalent chromium on performance and microbial community of an aerobic granular sequencing batch reactor.  

PubMed

The performance and microbial community of an aerobic granular sequencing batch reactor (GSBR) were investigated at different hexavalent chromium (Cr(VI)) concentrations. The COD and NH4 (+)-N removal efficiencies decreased with the increase in Cr(VI) concentration from 0 to 30 mg/L. The specific oxygen utilization rate (SOUR) decreased from 34.86 to 12.18 mg/(g mixed liquor suspended sludge (MLSS)·h) with the increase in Cr(VI) concentration from 0 to 30 mg/L. The specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) decreased with the increase in Cr(VI) concentration, whereas the SNRR was always higher than the sum of SAOR and SNOR at 0-30 mg/L Cr(VI). The scanning electron micrographs (SEM) showed some undefined particles on the surface of filamentous bacteria that might be the chelation of chromium and macromolecular organics at 30 mg/L Cr(VI). The denaturing gradient gel electrophoresis (DGGE) profiles revealed that some microorganisms adapting to high Cr(VI) concentration gradually became the predominant bacteria, while others without Cr(VI)-tolerance capacity tended to deplete or weaken. Some bacteria could tolerate the toxicity of high Cr(VI) concentration in the aerobic GSBR, such as Propionibacteriaceae bacterium, Ochrobactrum anthropi, and Micropruina glycogenica. PMID:25318421

Wang, Zichao; Gao, Mengchun; She, Zonglian; Jin, Chunji; Zhao, Yangguo; Yang, Shiying; Guo, Liang; Wang, Sen

2014-10-17

305

Nitrogen-converting communities in aerobic granules at different hydraulic retention times (HRTs) and operational modes.  

PubMed

This study determined how the activity and number of nitrogen-converting microorganisms varied with changes in hydraulic retention time (HRT) and the operating regime of aerobic granular sequencing batch reactors (GSBRs) treating high-nitrogen wastewater. Continuously aerated (O-mode) GSBRs were operated at HRTs of 10-, 13- and 19-h. Then the same reactors were operated at identical HRTs but the cycles started with an anoxic phase (A/O mode). To investigate the microbial communities, DNA- and RNA-based relative real-time PCR was used. In all experimental reactors ammonium was fully removed with a removal rate up to 75 mg N-NH4 (+)/(L·h), and nitrification efficiency was above 90 %. The efficiency of the removal of oxidized nitrogen forms decreased with the lengthening of HRT. The study found that variable oxic conditions (A/O mode) in the GSBR cycle stimulated the simultaneous activity of ammonium oxidizing bacteria (AOB), N2O-reducers, and Anammox bacteria in aerobic granules. With both modes, the activity of nitrogen-converting bacteria was highest with a 13-h HRT. Shortening HRT, resulted in higher chemical oxygen demand and nitrogen loadings, which favored the growth of Anammox microorganisms in granules and caused a decrease in the number of AOB. With all HRTs, the number of Anammox microorganisms was about 1.5-times higher in A/O mode than in O mode. PMID:25367416

Cydzik-Kwiatkowska, Agnieszka; Wojnowska-Bary?a, Irena

2015-01-01

306

Back To Bacteria.  

ERIC Educational Resources Information Center

Explores new research about bacteria. Discusses bacterial genomes, archaea, unusual environments, evolution, pathogens, bacterial movement, biofilms, bacteria in the body, and a bacterial obsession. Contains 29 references. (JRH)

Flannery, Maura C.

1997-01-01

307

Effect of elevated salt concentrations on the aerobic granular sludge process: linking microbial activity with microbial community structure  

Microsoft Academic Search

The long- and short-term effects of salt on biological nitrogen and phosphorus removal processes were studied in an aerobic granular sludge reactor. The microbial community structure was investigated by PCR-denaturing gradient gel electrophoresis (DGGE) on 16S rRNA and amoA genes. PCR products obtained from genomic DNA and from rRNA after reverse transcription were compared to determine the presence of bacteria

J. P. Bassin; M. Pronk; G. Muyzer; R. Kleerebezem; M. Dezotti; M. C. M. Loosdrecht

2011-01-01

308

alk B homologs in thermophilic bacteria of the genus Geobacillus  

Microsoft Academic Search

Screening for alkane hydroxylase genes (alkB) was performed in thermophilic aerobic bacteria of the genus Geobacillus. Total DNAs were isolated from the biomass of 11 strains grown on a mixture of saturated C10–C20 hydrocarbons. Fragments of alkB genes were amplified by PCR with degenerate oligonucleotide primers, and the PCR products were cloned and sequenced. For\\u000a the first time, a set

T. P. Tourova; T. N. Nazina; E. M. Mikhailova; T. A. Rodionova; A. N. Ekimov; A. V. Mashukova; A. B. Poltaraus

2008-01-01

309

[Phylogenetic analysis of bacteria of extreme ecosystems].  

PubMed

Phylogenetic analysis of aerobic chemoorganotrophic bacteria of the two extreme regions (Dead Sea and West Antarctic) was performed on the basis of the nucleotide sequences of the 16S rRNA gene. Thermotolerant and halotolerant spore-forming bacteria 7t1 and 7t3 of terrestrial ecosystems Dead Sea identified as Bacillus licheniformis and B. subtilis subsp. subtilis, respectively. Taking into account remote location of thermotolerant strain 6t1 from closely related strains in the cluster Staphylococcus, 6t1 strain can be regarded as Staphylococcus sp. In terrestrial ecosystems, Galindez Island (Antarctic) detected taxonomically diverse psychrotolerant bacteria. From ornithogenic soil were isolated Micrococcus luteus O-1 and Microbacterium trichothecenolyticum O-3. Strains 4r5, 5r5 and 40r5, isolated from grass and lichens, can be referred to the genus Frondihabitans. These strains are taxonomically and ecologically isolated and on the tree diagram form the joint cluster with three isolates Frondihabitans sp., isolated from the lichen Austrian Alps, and psychrotolerant associated with plants F. cladoniiphilus CafT13(T). Isolates from black lichen in the different stationary observation points on the south side of a vertical cliff identified as: Rhodococcus fascians 181n3, Sporosarcina aquimarina O-7, Staphylococcus sp. 0-10. From orange biofilm of fouling on top of the vertical cliff isolated Arthrobacter sp. 28r5g1, from the moss-- Serratia sp. 6r1g. According to the results, Frondihabitans strains most frequently encountered among chemoorganotrophic aerobic bacteria in the Antarctic phytocenoses. PMID:25007437

Romanovskaia, V A; Parfenova, V V; Bel'kova, N L; Sukhanova, E V; Gladka, G V; Tashireva, A A

2014-01-01

310

Biosorption kinetics of cadmium(II) on aerobic granular sludge  

Microsoft Academic Search

Aerobic granules have excellent settle ability and high-porosity structure. This study investigated the feasibility of aerobic granules as a novel type of biosorbent, for cadmium removal from industrial wastewater. Batch tests were carried out at different initial Cd2+ and granule concentrations. Based on experimental data, a kinetic model was developed to describe Cd2+ biosorption by aerobic granules. Results showed that

Yu Liu; Shu-Fang Yang; Hui Xu; Kok-How Woon; Yue-Mei Lin; Joo-Hwa Tay

2003-01-01

311

Developmental plasticity in aerobic performance in deer mice ( Peromyscus maniculatus)  

Microsoft Academic Search

While several studies have examined the abiotic effects of altitude (low ambient temperatures and hypoxia) on the aerobic performance of small mammals, few have explored the effects of development and maturation at different altitudes on aerobic performance as adults. We examined the basal metabolism and aerobic performance of deer mice (Peromyscus maniculatus) under four different developmental and testing regimes: (1)

K. A. Hammond; M. A. Chappell; D. M. Kristan

2002-01-01

312

AEROBIC DENITRIFICATION: IMPLICATIONS FOR NITROGEN FATE MODELING  

EPA Science Inventory

In the Mississippi, as well as most nitrogen-degraded rivers and streams, NO3- is the dominant N species and therefore understanding its biogeochemical behavior is critical for accurate nitrogen fate modeling. To our knowledge this is the first work to report aerobic denitrificat...

313

Media for the aerobic growth of campylobacter  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of agar and sodium bicarbonate (NaHCO3) concentration on aerobic growth of Campylobacter in a fumarate-pyruvate medium was examined. The broth medium was supplemented with 0.0 to 0.2% agar and inoculated with 106 CFU/ml of Campylobacter coli 33559, Campylobacter fetus 27349, Campylobacter...

314

Aerobic respiration in pelagic marine sediments  

Microsoft Academic Search

Analyses for dissolved oxygen, nitrate and total CO 2 in the interstitial water have been combined with solid phase sediment analyses of carbon and nitrogen to calculate the rates of reaction and stoichiometry of decomposing organic matter in central Equatorial Pacific pelagic sediments. The diagenesis is dominated by aerobic respiration and nitrification. Organic carbon and total nitrogen decrease exponentially with

Varis Grundmanis; James W. Murray

1982-01-01

315

Aerobic Exercise Prescription for Rheumatoid Arthritics.  

ERIC Educational Resources Information Center

The use of exercise as a general treatment for rheumatoid arthritics (RA) has included range of motion, muscular strength, water exercise and rest therapy while virtually ignoring possible benefits of aerobic exercise. The purposes of this project were to examine the guidelines for exercise prescription in relation to this special population and…

Evans, Blanche W.; Williams, Hilda L.

316

Ecophysiological Characteristics of Obligate Methanotrophic Bacteria and Methane Oxidation In Situ  

NASA Technical Reports Server (NTRS)

Most of the obligate methane-oxidizing bacteria (MOB) described to date are neutrophilic mesophiles that grow optimally in dilute media. Kinetic analyses generally indicate that bacterial methane uptake occurs by transport systems with a K(sub m) greater than l micronM. These and other properties of MOB are inconsistent with characteristics of methane oxidation in situ. The inconsistencies indicate a need for greater attention to the ecophysiological characteristics of isolates and the design of enrichment and isolation schemes which emphasize ecologically relevant parameters (e.g., low temperature, limited and diverse substrate availability, low water potential).

King, Gary M.

1993-01-01

317

Submerged filter biotreatment of hazardous leachate in aerobic, anaerobic, and anaerobic\\/aerobic systems  

Microsoft Academic Search

Aerobic, anaerobic and anaerobic\\/aerobic biotreatment of an industrial hazardous waste landfill leachate was evaluated in bench scale biofilm reactor systems operated under steady-and non-steady-state conditions. The leachate contained volatile and semi-volatile organics that exceeded the best-demonstrated-available-technology (BDAT) standard established for multi-source leachate wastewater under the Resources Conservation and Recovery Act (RCRA). The influent leachate stream was continuously applied to three

1995-01-01

318

Peroxide-Sensing Transcriptional Regulators in Bacteria  

PubMed Central

The ability to maintain intracellular concentrations of toxic reactive oxygen species (ROS) within safe limits is essential for all aerobic life forms. In bacteria, as well as other organisms, ROS are produced during the normal course of aerobic metabolism, necessitating the constitutive expression of ROS scavenging systems. However, bacteria can also experience transient high-level exposure to ROS derived either from external sources, such as the host defense response, or as a secondary effect of other seemingly unrelated environmental stresses. Consequently, transcriptional regulators have evolved to sense the levels of ROS and coordinate the appropriate oxidative stress response. Three well-studied examples of these are the peroxide responsive regulators OxyR, PerR, and OhrR. OxyR and PerR are sensors of primarily H2O2, while OhrR senses organic peroxide (ROOH) and sodium hypochlorite (NaOCl). OxyR and OhrR sense oxidants by means of the reversible oxidation of specific cysteine residues. In contrast, PerR senses H2O2 via the Fe-catalyzed oxidation of histidine residues. These transcription regulators also influence complex biological phenomena, such as biofilm formation, the evasion of host immune responses, and antibiotic resistance via the direct regulation of specific proteins. PMID:22797754

Mongkolsuk, Skorn

2012-01-01

319

Petrimonas sulfuriphila gen. nov., sp. nov., a mesophilic fermentative bacterium isolated from a biodegraded oil reservoir.  

PubMed

A mesophilic, anaerobic, fermentative bacterium, strain BN3(T), was isolated from a producing well of a biodegraded oil reservoir in Canada. Cells were Gram-negative, non-motile rods that did not form spores. The temperature range for growth was 15-40 degrees C, with optimum growth at 37-40 degrees C. The strain grew with up 4 % NaCl, with optimum growth in the absence of NaCl. Tryptone was required for growth. Yeast extract and elemental sulfur stimulated growth. Growth was also enhanced during fermentation of glucose, arabinose, galactose, maltose, mannose, rhamnose, lactose, ribose, fructose, sucrose, cellobiose, lactate, mannitol and glycerol. Acetate, hydrogen and CO(2) were produced during glucose fermentation. Elemental sulfur and nitrate were used as electron acceptors and were reduced to sulfide and ammonium, respectively. The G + C content of the genomic DNA was 40.8 mol%. Phylogenetic analyses of the 16S rRNA gene sequence indicated that the strain was a member of the phylum 'Bacteroidetes', distantly related to the genera Bacteroides and Tannerella (similarity values of less than 90 %). The chemotaxonomic data (fatty acids, polar lipids and quinones composition) also indicated that strain BN3(T) could be clearly distinguished from its closest cultivated relatives. This novel organism possesses phenotypic, chemotaxonomic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, it is proposed that this isolate should be described as a member of a novel species of a new genus, Petrimonas gen. nov., of which Petrimonas sulfuriphila sp. nov. is the type species. The type strain is BN3(T) (= DSM 16547(T) = JCM 12565(T)). PMID:15879242

Grabowski, Agnčs; Tindall, Brian J; Bardin, Véronique; Blanchet, Denis; Jeanthon, Christian

2005-05-01

320

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions.  

PubMed

With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO(2) emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH(4) production yield (MPY) and VS reduction achieved in this condition were 5.0m(3)/m(3)/d, 0.25 m(3) CH(4)/g COD(added), and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m(3)/m(3)/d, MPY of 0.26 m(3) CH(4)/g COD(added), and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes. PMID:21684733

Kim, Dong-Hoon; Oh, Sae-Eun

2011-01-01

321

Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.  

PubMed

Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. PMID:23116231

Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

2012-12-01

322

Bacteria in the transfer catheter tip influence the live-birth rate after in vitro fertilization  

Microsoft Academic Search

Objective: To assess the impact of individual bacteria isolated from the vagina and tip of the embryo transfer catheter on live-birth rates.Design: Prospective clinical study.Setting: Infertility outpatient clinic of a university hospital.Patient(s): Ninety-one women undergoing IVF-ET.Intervention(s): Cultures were obtained from the vagina for aerobic and anaerobic bacteria at the time of both sonographic egg retrieval and embryo transfer and from

Donald E Moore; Michael R Soules; Nancy A Klein; Victor Y Fujimoto; Kathy J Agnew; David A Eschenbach

2000-01-01

323

Effects of Storage in an Anaerobic Transport System on Bacteria in Known Polymicrobial Mixtures and in Clinical Specimens  

PubMed Central

An anaerobic transport system (ATS) which provides for catalytic removal of oxygen was evaluated by using in vitro-prepared polymicrobial mixtures of logphase bacteria and clinical specimens. Inoculated swabs were stored at room temperature in (i) aerobic, (ii) anaerobic glove box, and (iii) ATS environments, and bacteria were quantitated after 2, 24, 48, and 72 h. Bacteria in a three-part mixture of Bacteroides fragilis, Peptostreptococcus anaerobius, and Escherichia coli and in a five-part mixture of B. fragilis, P. anaerobius, Fusobacterium nucleatum, Staphylococcus epidermidis, and Pseudomonas aeruginosa survived 72 h of storage in the ATS and anaerobic glove box environments, but the anaerobic species were inactivated in the aerobic storage except for B. fragilis in pure culture or in the three-part mixture. Changes in relative proportions among the species in a mixture were least in the ATS and anaerobic glove box environments and greatest during the aerobic storage, particularly in the five-part mixture. Bacteria present in pure or mixed culture in clinical specimens generally survived 72 h of storage in the ATS. These data indicate that changes in relative proportions occur with prolonged storage even under anaerobic conditions, but that the ATS would be most effective for preserving anaerobic bacteria and preventing drastic concentration changes and overgrowth of facultative and aerobic bacteria. Images PMID:370142

Hill, Gale B.

1978-01-01

324

Laboratory experiments on the weathering of iron meteorites and carbonaceous chondrites by iron-oxidizing bacteria  

NASA Astrophysics Data System (ADS)

Batch culture experiments were performed to investigate the weathering of meteoritic material by iron-oxidizing bacteria. The aerobic, acidophilic iron oxidizer (A. ferrooxidans) was capable of oxidizing iron from both carbonaceous chondrites (Murchison and Cold Bokkeveld) and iron meteorites (York and Casas Grandes). Preliminary iron isotope results clearly show contrasted iron pathways during oxidation with and without bacteria suggesting that a biological role in meteorite weathering could be distinguished isotopically. Anaerobic iron-oxidizers growing under pH-neutral conditions oxidized iron from iron meteorites. These results show that rapid biologicallymediated alteration of extraterrestrial materials can occur in both aerobic and anaerobic environments. These results also demonstrate that iron can act as a source of energy for microorganisms from both iron and carbonaceous chondrites in aerobic and anaerobic conditions with implications for life on the early Earth and the possible use of microorganisms to extract minerals from asteroidal material.

Gronstal, A.; Pearson, V.; Kappler, A.; Dooris, C.; Anand, M.; Poitrasson, F.; Kee, T. P.; Cockell, C. S.

2009-03-01

325

5-Aminolaevulinic acid (ALA) induced formation of different fluorescent porphyrins: A study of the biosynthesis of porphyrins by bacteria of the human digestive tract  

Microsoft Academic Search

Aminolaevulinic acid (ALA) induces porphyrin formation in almost all living cells. The fluorescence spectra of porphyrins produced from a variety of 31 bacterial strains from the human oral cavity and other parts of digestive tract have been examined. Many of the bacteria exposed to ALA were able to induce protoporphyrin IX (PpIX) fluorescence, but under aerobic condition some bacteria can

Wieland Dietel; Roy Pottier; Wolfgang Pfister; Peter Schleier; Karen Zinner

2007-01-01

326

Ammonia Oxidizing Bacteria Community Dynamics in a Pilot-Scale Wastewater Treatment Plant  

Microsoft Academic Search

BackgroundChemoautotrophic ammonia oxidizing bacteria (AOB) have the metabolic ability to oxidize ammonia to nitrite aerobically. This metabolic feature has been widely used, in combination with denitrification, to remove nitrogen from wastewater in wastewater treatment plants (WWTPs). However, the relative influence of specific deterministic environmental factors to AOB community dynamics in WWTP is uncertain. The ecological principles underlying AOB community dynamics

Xiaohui Wang; Xianghua Wen; Yu Xia; Ma Hu; Fang Zhao; Kun Ding

2012-01-01

327

In Vitro Activities of OPT-80 and Comparator Drugs against Intestinal Bacteria  

PubMed Central

The activities of OPT-80 against 453 intestinal bacteria were compared with those of seven other drugs. OPT-80 showed good activity against most clostridia, staphylococci, and enterococci, but streptococci, aerobic and facultative gram-negative rods, anaerobic gram-negative rods, and Clostridium ramosum were resistant. Poor activity against anaerobic gram-negative rods may maintain colonization resistance. PMID:15561877

Finegold, Sydney M.; Molitoris, Denise; Vaisanen, Marja-Liisa; Song, Yuli; Liu, Chengxu; Bolańos, Mauricio

2004-01-01

328

Reductive dechlorination of Tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions.  

PubMed Central

Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 mumol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 mumol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 to -150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions. PMID:1892393

Kästner, M

1991-01-01

329

Methane oxidation in a crude oil contaminated aquifer: Delineation of aerobic reactions at the plume fringes  

USGS Publications Warehouse

High resolution direct-push profiling over short vertical distances was used to investigate CH4 attenuation in a petroleum contaminated aquifer near Bemidji, Minnesota. The contaminant plume was delineated using dissolved gases, redox sensitive components, major ions, carbon isotope ratios in CH4 and CO2, and the presence of methanotrophic bacteria. Sharp redox gradients were observed near the water table. Shifts in ??13CCH4 from an average of - 57.6??? (?? 1.7???) in the methanogenic zone to - 39.6??? (?? 8.7???) at 105 m downgradient, strongly suggest CH4 attenuation through microbially mediated degradation. In the downgradient zone the aerobic/anaerobic transition is up to 0.5 m below the water table suggesting that transport of O2 across the water table is leading to aerobic degradation of CH4 at this interface. Dissolved N2 concentrations that exceeded those expected for water in equilibrium with the atmosphere indicated bubble entrapment followed by preferential stripping of O2 through aerobic degradation of CH4 or other hydrocarbons. Multivariate and cluster analysis were used to distinguish between areas of significant bubble entrapment and areas where other processes such as the infiltration of O 2 rich recharge water were important O2 transport mechanisms. ?? 2011 Elsevier B.V. All rights reserved.

Amos, R.T.; Bekins, B.A.; Delin, G.N.; Cozzarelli, I.M.; Blowes, D.W.; Kirshtein, J.D.

2011-01-01

330

Clinical comparison of the isolator and BacT/Alert aerobic blood culture systems.  

PubMed

The performance characteristics of the Isolator (Wampole Laboratories, Cranbury, N.J.) and the BacT/Alert (Organon Teknika Corporation, Durham, N.C.) aerobic blood culture systems were compared for 6,009 blood culture sets obtained from patients with suspected bloodstream infections. The BacT/Alert aerobic bottle [BTA(O2)] was continuously agitated while it was incubated in 5% CO2 at 36 degrees C; culture plates prepared from the Isolator tube [I(O2)] were incubated in 5% CO2 at 37 degrees C. From 394 blood cultures, 416 clinically significant isolates of bacteria and yeasts were recovered. The overall yields for BTA(O2) and I(O2) were not significantly different (319 versus 336; P = 0.20). I(O2) recovered significantly more staphylococcus (P < 0.05) and yeast isolates (P < 0.01). BTA(O2) recovered significantly more aerobic and facultatively anaerobic gram-negative bacilli (P < 0.05). In blood culture sets which produced growth of the same organisms in both the BTA(O2) and I(O2) systems, the BTA(O2) system detected growth sooner, but more rapid identification was possible with the I(O2) system by virtue of earlier isolation of colonies on solid media. PMID:7665647

Hellinger, W C; Cawley, J J; Alvarez, S; Hogan, S F; Harmsen, W S; Ilstrup, D M; Cockerill, F R

1995-07-01

331

Is it possible to stabilize a thermophilic protein further using sequences and structures of mesophilic proteins: a theoretical case study concerning DgAS.  

PubMed

Incorporating structural elements of thermostable homologs can greatly improve the thermostability of a mesophilic protein. Despite the effectiveness of this method, applying it is often hampered. First, it requires alignment of the target mesophilic protein sequence with those of thermophilic homologs, but not every mesophilic protein has a thermophilic homolog. Second, not all favorable features of a thermophilic protein can be incorporated into the structure of a mesophilic protein. Furthermore, even the most stable native protein is not sufficiently stable for industrial applications. Therefore, creating an industrially applicable protein on the basis of the thermophilic protein could prove advantageous. Amylosucrase (AS) can catalyze the synthesis of an amylose-like polysaccharide composed of only ?-1,4-linkages using sucrose as the lone energy source. However, industrial development of AS has been hampered owing to its low thermostability. To facilitate potential industrial applications, the aim of the current study was to improve the thermostability of Deinococcus geothermalis amylosucrase (DgAS) further; this is the most stable AS discovered to date. By integrating ideas from mesophilic AS with well-established protein design protocols, three useful design protocols are proposed, and several promising substitutions were identified using these protocols. The successful application of this hybrid design method indicates that it is possible to stabilize a thermostable protein further by incorporating structural elements of less-stable homologs. PMID:23575217

Liu, Ming; He, Hongqiu; Su, Jiguo

2013-01-01

332

Is it possible to stabilize a thermophilic protein further using sequences and structures of mesophilic proteins: a theoretical case study concerning DgAS  

PubMed Central

Incorporating structural elements of thermostable homologs can greatly improve the thermostability of a mesophilic protein. Despite the effectiveness of this method, applying it is often hampered. First, it requires alignment of the target mesophilic protein sequence with those of thermophilic homologs, but not every mesophilic protein has a thermophilic homolog. Second, not all favorable features of a thermophilic protein can be incorporated into the structure of a mesophilic protein. Furthermore, even the most stable native protein is not sufficiently stable for industrial applications. Therefore, creating an industrially applicable protein on the basis of the thermophilic protein could prove advantageous. Amylosucrase (AS) can catalyze the synthesis of an amylose-like polysaccharide composed of only ?-1,4-linkages using sucrose as the lone energy source. However, industrial development of AS has been hampered owing to its low thermostability. To facilitate potential industrial applications, the aim of the current study was to improve the thermostability of Deinococcus geothermalis amylosucrase (DgAS) further; this is the most stable AS discovered to date. By integrating ideas from mesophilic AS with well-established protein design protocols, three useful design protocols are proposed, and several promising substitutions were identified using these protocols. The successful application of this hybrid design method indicates that it is possible to stabilize a thermostable protein further by incorporating structural elements of less-stable homologs. PMID:23575217

2013-01-01

333

Genomics of Aerobic Cellulose Utilization Systems in Actinobacteria  

PubMed Central

Cellulose degrading enzymes have important functions in the biotechnology industry, including the production of biofuels from lignocellulosic biomass. Anaerobes including Clostridium species organize cellulases and other glycosyl hydrolases into large complexes known as cellulosomes. In contrast, aerobic actinobacteria utilize systems comprised of independently acting enzymes, often with carbohydrate binding domains. Numerous actinobacterial genomes have become available through the Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. We identified putative cellulose-degrading enzymes belonging to families GH5, GH6, GH8, GH9, GH12, GH48, and GH51 in the genomes of eleven members of the actinobacteria. The eleven organisms were tested in several assays for cellulose degradation, and eight of the organisms showed evidence of cellulase activity. The three with the highest cellulase activity were Actinosynnema mirum, Cellulomonas flavigena, and Xylanimonas cellulosilytica. Cellobiose is known to induce cellulolytic enzymes in the model organism Thermobifida fusca, but only Nocardiopsis dassonvillei showed higher cellulolytic activity in the presence of cellobiose. In T. fusca, cellulases and a putative cellobiose ABC transporter are regulated by the transcriptional regulator CelR. Nine organisms appear to use the CelR site or a closely related binding site to regulate an ABC transporter. In some, CelR also regulates cellulases, while cellulases are controlled by different regulatory sites in three organisms. Mining of genome data for cellulose degradative enzymes followed by experimental verification successfully identified several actinobacteria species which were not previously known to degrade cellulose as cellulolytic organisms. PMID:22723998

Anderson, Iain; Abt, Birte; Lykidis, Athanasios; Klenk, Hans-Peter; Kyrpides, Nikos; Ivanova, Natalia

2012-01-01

334

Distributions of putative aerobic methanotrophs in diverse pelagic marine environments.  

PubMed

Aerobic methane oxidization in the pelagic ocean serves an important role in limiting methane release to the atmosphere, yet little is known about the identity and distribution of bacteria that mediate this process. The distribution of putative methane-oxidizing marine groups, OPU1, OPU3 and Group X, was assessed in different ocean provinces using a newly developed fingerprinting method (monooxygenase intergenic spacer analysis (MISA)) in combination with pmoA clone library analysis and quantitative PCR (qPCR). The distribution of these three distinct monooxygenase groups, previously reported from pelagic marine environments, was examined in 39 samples including active methane seeps in the Gulf of Mexico and Santa Monica Bay, submarine canyon heads along the California continental margin, an oligotrophic subtropical gyre and areas proximal to a hydrothermal vent in the North Fiji back-arc basin. OPU1 and OPU3 were widely and similarly distributed within the meso- and bathypelagic zone (110 to approximately 2000 m water depth) and showed a >50-fold greater abundance near methane seeps relative to non-seep sites. In contrast, Group X was predominantly recovered from samples along the California margin, at both seep and non-seep sites. All three phylotypes were below detection in the epipelagic zone to depths of 100 m. Several additional deeply branching monooxygenase sequences were also identified in this study, indicating the presence of uncharacterized groups of microorganisms potentially involved in the cycling of methane or ammonium. PMID:20147984

Tavormina, Patricia L; Ussler, William; Joye, Samantha B; Harrison, Benjamin K; Orphan, Victoria J

2010-05-01

335

Aerobic residential onsite sewage systems: an evaluation of treated-effluent quality.  

PubMed

This retrospective cohort study used existing data to evaluate the quality of effluent from three of the most common types of onsite residential aerobic treatment sewage systems (Multi-Flo, Norweco, and Whitewater) installed in Kitsap County, Washington. Five-day biochemical oxygen demand (BOD5), total suspended solids (TSS), and fecal-coliform-bacteria parameters were used to determine performance. Although most (77 percent) of the systems were less than one year old at the time of sampling, over a third failed to meet NSF certification standards for BOD5 and TSS in effluent (< 30 milligrams per liter [mg/L]). Over two-thirds of systems failed to meet Washington State Board of Health Treatment Standard 2 criteria for BOD5 and TSS (< 10 mg/L). Furthermore, an average of 59 percent of the systems failed to meet state standards for fecal coliform (< 800 fecal coliform bacteria per 100 milliliters). PMID:14556365

Maxfield, Meliss; Daniell, William E; Treser, Charles D; VanDerslice, Jim

2003-10-01

336

High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: A pilot scale study  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer High temperatures were tested in single and two-stage anaerobic digestion of waste activated sludge. Black-Right-Pointing-Pointer The increased temperature demonstrated the possibility of improving typical yields of the conventional mesophilic process. Black-Right-Pointing-Pointer The temperature phased anaerobic digestion process (65 + 55 Degree-Sign C) showed the best performances with yields of 0.49 m{sup 3}/kgVS{sub fed}. Black-Right-Pointing-Pointer Ammonia and phosphate released from solids destruction determined the precipitation of struvite in the reactor. - Abstract: The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35 Degree-Sign C), thermophilic (55 Degree-Sign C) and temperature phased (65 + 55 Degree-Sign C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m{sup 3}d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m{sup 3}/kgVS{sub fed} at 35, 55, and 65 + 55 Degree-Sign C, respectively. The extreme thermophilic reactor working at 65 Degree-Sign C showed a high hydrolytic capability and a specific yield of 0.33 gCOD (soluble) per gVS{sub fed}. The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile fatty acids of 20 and 9 g/l, respectively. Acetic and propionic acids were the main compounds found in the acids mixture. Because of the improved digestion efficiency, organic nitrogen and phosphorus were solubilised in the bulk. Their concentration, however, did not increase as expected because of the formation of salts of hydroxyapatite and struvite inside the reactor.

Bolzonella, David, E-mail: david.bolzonella@univr.it [University of Verona, Department of Biotechnology, Strada Le Grazie, 15, 37134 Verona (Italy); Cavinato, Cristina, E-mail: cavinato@unive.it [University of Venice, Department of Environmental Sciences, Computer Science and Statistics, Dorsoduro 2137, 30123 Venice (Italy); Fatone, Francesco, E-mail: francesco.fatone@univr.it [University of Verona, Department of Biotechnology, Strada Le Grazie, 15, 37134 Verona (Italy); Pavan, Paolo, E-mail: pavan@unive.it [University of Venice, Department of Environmental Sciences, Computer Science and Statistics, Dorsoduro 2137, 30123 Venice (Italy); Cecchi, Franco, E-mail: franco.cecchi@univr.it [University of Verona, Department of Biotechnology, Strada Le Grazie, 15, 37134 Verona (Italy)

2012-06-15

337

Bacillus acidicola sp. nov., a novel mesophilic, acidophilic species isolated from acidic Sphagnum peat bogs in Wisconsin  

Microsoft Academic Search

A mesophilic, acidophilic, spore-forming bacterium, strain 105-2T, was isolated from an acidic Sphagnum peat bog in Wisconsin, USA. Strain 105-2T has 16S rRNA gene sequence similarity to Bacillus sporothermodurans DSM 10599T and Bacillus oleronius DSM 9356T of 97?4 and 97?8%, respectively. The primary lipoquinone is MK-7 and the major fatty acids are 15:0 iso, 15:0 anteiso and 17:0 anteiso. The

Richard A. Albert

2005-01-01

338

Microbial communities of aerobic granules: granulation mechanisms.  

PubMed

Aerobic granulation is an advanced biological wastewater treatment technology. This study for the first time identified the microbial communities of sliced samples of mature granules by polymerase chain reaction (PCR) amplification and denaturing gradient gel electrophoresis (DGGE) technique and those of whole growing granules by high-throughput sequencing technique. The sliced sample study revealed that mature granules have a spherical core with anaerobic Rhodocyclaceae covered by an outer spherical shell with both aerobic and anaerobic strains. The growing granule study showed that the flocculated flocs were first transited to young granules with increased abundances of Flavobacteriaceae, Xanthomonadaceae, Rhodobacteraceae and Microbacteriaceae, then the abundances of anaerobic strains were increased owing to the formation of anaerobic core. Since the present granules were cultivated from flocculated flocs, the microbial community data suggested that granules were formed via a deterministic rather than via a random aggregation-disintegration mechanism. PMID:25063977

Lv, Yi; Wan, Chunli; Lee, Duu-Jong; Liu, Xiang; Tay, Joo-Hwa

2014-10-01

339

Aerobic metabolism underlies complexity and capacity  

PubMed Central

The evolution of biological complexity beyond single-celled organisms was linked temporally with the development of an oxygen atmosphere. Functionally, this linkage can be attributed to oxygen ranking high in both abundance and electronegativity amongst the stable elements of the universe. That is, reduction of oxygen provides for close to the largest possible transfer of energy for each electron transfer reaction. This suggests the general hypothesis that the steep thermodynamic gradient of an oxygen environment was permissive for the development of multicellular complexity. A corollary of this hypothesis is that aerobic metabolism underwrites complex biological function mechanistically at all levels of organization. The strong contemporary functional association of aerobic metabolism with both physical capacity and health is presumably a product of the integral role of oxygen in our evolutionary history. Here we provide arguments from thermodynamics, evolution, metabolic network analysis, clinical observations and animal models that are in accord with the centrality of oxygen in biology. PMID:17947307

Koch, Lauren G; Britton, Steven L

2008-01-01

340

Aerobic Biodegradation of N-Nitrosodimethylamine (NDMA)  

E-print Network

- ance in the environment is related to the release of rocket fuel and to chlorine-based disinfection or biochemistry involved. This study shows that bacteria expressing monooxygenase en- zymes functionally similar sidechain monooxygenase were not capable of NDMA degradation. In addition, bacteria expressing aromatic

Wood, Thomas K.

341

Skeletal muscle mitochondria: the aerobic gate?  

PubMed

At an animal's maximum aerobic capacity (VO2max), the O2 flowing through the respiratory system is consumed by a functionally exclusive sink, skeletal muscle mitochondria. Thus, O2 consumption will never exceed the muscles O2 demand. If the system is ideally designed, structures upstream to the skeletal muscle O2 sink must be built to insure adequate O2 delivery to the working muscle. There are a number of structure-function solutions available to supply the demanded O2 to the muscle; these have been found to vary, often ontogenetically, with hypoxia, training, etc. But there is one relationship that is invariant: Total O2 uptake can be predicted by the total (active) skeletal muscle mitochondrial volume. In aerobic and sedentary animals, across a range of body sizes, maximum (in vivo) mitochondrial O2 consumption is constant among mammals (at approximately 2000 O2 molecules per square micron of inner mitochondrial membrane per second). Because the volume of mitochondria is one of the most plastic of all respiratory structures, we interpret this relationship as suggesting that skeletal muscle mitochondria alone sets the demand for O2 and, thus, the volume of skeletal muscle mitochondria dictates an animal's maximum aerobic capacity. PMID:3289318

Lindstedt, S L; Wells, D J

1988-01-01

342

Modeling aerobic biodegradation in the capillary fringe.  

PubMed

Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone. PMID:25548946

Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

2015-02-01

343

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions  

SciTech Connect

Highlights: > High-solids (dry) anaerobic digestion is attracting a lot of attention these days. > One reactor was fed with food waste (FW) and paper waste. > Maximum biogas production rate of 5.0 m{sup 3}/m{sup 3}/d was achieved at HRT 40 d and 40% TS. > The other reactor was fed with FW and livestock waste (LW). > Until a 40% LW content increase, the reactor exhibited a stable performance. - Abstract: With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO{sub 2} emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH{sub 4} production yield (MPY) and VS reduction achieved in this condition were 5.0 m{sup 3}/m{sup 3}/d, 0.25 m{sup 3} CH{sub 4}/g COD{sub added}, and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m{sup 3}/m{sup 3}/d, MPY of 0.26 m{sup 3} CH{sub 4}/g COD{sub added}, and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.

Kim, Dong-Hoon [Wastes Energy Research Center, Korea Institute of Energy Research, 102, Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Oh, Sae-Eun, E-mail: saeun@hanbat.ac.kr [Department of Environmental Engineering, Hanbat National University, San 16-1, Duckmyoung-dong, Yuseong-gu, Daejeon (Korea, Republic of)

2011-09-15

344

Determinants for the improved thermostability of a mesophilic family 11 xylanase predicted by computational methods  

PubMed Central

Background Xylanases have drawn much attention owing to possessing great potential in various industrial applications. However, the applicability of xylanases, exemplified by the production of bioethanol and xylooligosaccharides (XOSs), was bottlenecked by their low stabilities at higher temperatures. The main purpose of this work was to improve the thermostability of AuXyn11A, a mesophilic glycoside hydrolase (GH) family 11 xylanase from Aspergillus usamii E001, by N-terminus replacement. Results A hybrid xylanase with high thermostability, named AEXynM, was predicted by computational methods, and constructed by substituting the N-terminal 33 amino acids of AuXyn11A with the corresponding 38 ones of EvXyn11TS, a hyperthermostable family 11 xylanase. Two AuXyn11A- and AEXynM-encoding genes, Auxyn11A and AExynM, were then highly expressed in Pichia pastoris GS115, respectively. The specific activities of two recombinant xylanases (reAuXyn11A and reAEXynM) were 10,437 and 9,529 U mg-1. The temperature optimum and stability of reAEXynM reached 70 and 75°C, respectively, much higher than those (50 and 45°C) of reAuXyn11A. The melting temperature (Tm) of reAEXynM, measured using the Protein Thermal Shift (PTS) method, increased by 34.0°C as compared with that of reAuXyn11A. Analyzed by HPLC, xylobiose and xylotriose as the major hydrolytic products were excised from corncob xylan by reAEXynM. Additionally, three single mutant genes from AExynM (AExynMC5T, AExynMP9S, and AExynMH14N) were constructed by site-directed mutagenesis as designed theoretically, and expressed in P. pastoris GS115, respectively. The thermostabilities of three recombinant mutants clearly decreased as compared with that of reAEXynM, which demonstrated that the three amino acids (Cys5, Pro9, and His14) in the replaced N-terminus contributed mainly to the high thermostability of AEXynM. Conclusions This work highly enhanced the thermostability of AuXyn11A by N-terminus replacement, and further verified, by site-directed mutagenesis, that Cys5, Pro9, and His14 contributed mainly to the improved thermostability. It will provide an effective strategy for improving the thermostabilities of other enzymes. PMID:24393334

2014-01-01

345

Antibiotic resistance among bacteria isolated from seawater and penguin fecal samples collected near Palmer Station, Antarctica.  

PubMed

Antibiotic resistance in aquatic bacteria has increased steadily as a consequence of the widespread use of antibiotics, but practice and international treaty should have limited antibiotic contamination in Antarctica. We estimated antibiotic resistance in microorganisms isolated from the Antarctic marine waters and a penguin rookery, for 2 reasons: (i) as a measure of human impact and (ii) as a potential "snapshot" of the preantibiotic world. Samples were taken at 4 established sampling sites near Palmer Station, which is situated at the southern end of the Palmer Archipelago (64 degrees 10'S, 61 degrees 50'W). Sites were chosen to provide different potentials for human contamination. Forty 50 mL samples of seawater were collected and colony-forming units (CFU)/mL were determined at 6 and 20 degrees C. For this study, presumed psychrophiles (growth at 6 degrees C) were assumed to be native to Antarctic waters, whereas presumed mesophiles (growth at 20 degrees C but not at 6 degrees C) were taken to represent introduced organisms. The 20-6 degrees C CFU/mL ratio was used as a measure of the relative impact to the ecosystem of presumably introduced organisms. This ratio was highest at the site nearest to Palmer Station and decreased with distance from it, suggesting that human presence has impacted the natural microbial flora of the site. The frequency of resistance to 5 common antibiotics was determined in each group of isolates. Overall drug resistance was higher among the presumed mesophiles than the presumed psychrophiles and increased with proximity to Palmer Station, with the presumed mesophiles showing higher frequencies of single and multiple drug resistance than the psychrophile population. The frequency of multidrug resistance followed the same pattern. It appears that multidrug resistance is low among native Antarctic bacteria but is increased by human habitation. PMID:19190699

Miller, Robert V; Gammon, Katharine; Day, Martin J

2009-01-01

346

Discrimination between mesophilic and psychrotolerant strains in the Bacillus cereus group based on the PstI digestion of the pycA gene.  

PubMed

A simple and rapid assay for the detection of Bacillus weihenstephanensis isolates and other psychrotolerant strains in the Bacillus cereus group was developed. It is based on the presence of a nucleotide substitution at position 795 on the housekeeping pycA gene in all B. weihenstephanensis strains. This mutation creates a PstI recognition site. It is absent in mesophilic strains in the B. cereus group. The pycA gene is amplified by PCR and the amplicons submitted to PstI digestions. In mesophilic strains, a single band of 1,718 bp in length is visualised on an agarose gel. In B. weihenstephanensis strains and in all other psychrotolerant strains from the B. cereus group, the amplicons are cleaved and two bands of 1,175 and 543 bp, respectively, are visualised. This method could be used for the screening of B. cereus collections and for the identification of psychrotolerant and mesophilic isolates from different environments. PMID:23475137

Soufiane, Brahim; Cōté, Jean-Charles

2013-08-01

347

Aerobic methanotrophic communities at the Red Sea brine-seawater interface.  

PubMed

The central rift of the Red Sea contains 25 brine pools with different physicochemical conditions, dictating the diversity and abundance of the microbial community. Three of these pools, the Atlantis II, Kebrit and Discovery Deeps, are uniquely characterized by a high concentration of hydrocarbons. The brine-seawater interface, described as an anoxic-oxic (brine-seawater) boundary, is characterized by a high methane concentration, thus favoring aerobic methane oxidation. The current study analyzed the aerobic free-living methane-oxidizing bacterial communities that potentially contribute to methane oxidation at the brine-seawater interfaces of the three aforementioned brine pools, using metagenomic pyrosequencing, 16S rRNA pyrotags and pmoA library constructs. The sequencing of 16S rRNA pyrotags revealed that these interfaces are characterized by high microbial community diversity. Signatures of aerobic methane-oxidizing bacteria were detected in the Atlantis II Interface (ATII-I) and the Kebrit Deep Upper (KB-U) and Lower (KB-L) brine-seawater interfaces. Through phylogenetic analysis of pmoA, we further demonstrated that the ATII-I aerobic methanotroph community is highly diverse. We propose four ATII-I pmoA clusters. Most importantly, cluster 2 groups with marine methane seep methanotrophs, and cluster 4 represent a unique lineage of an uncultured bacterium with divergent alkane monooxygenases. Moreover, non-metric multidimensional scaling (NMDS) based on the ordination of putative enzymes involved in methane metabolism showed that the Kebrit interface layers were distinct from the ATII-I and DD-I brine-seawater interfaces. PMID:25295031

Abdallah, Rehab Z; Adel, Mustafa; Ouf, Amged; Sayed, Ahmed; Ghazy, Mohamed A; Alam, Intikhab; Essack, Magbubah; Lafi, Feras F; Bajic, Vladimir B; El-Dorry, Hamza; Siam, Rania

2014-01-01

348

Microbial diversity differences within aerobic granular sludge and activated sludge flocs.  

PubMed

In this study, we investigated during 400 days the microbial community variations as observed from 16S DNA gene DGGE banding patterns from an aerobic granular sludge pilot plant as well as the from a full-scale activated sludge treatment plant in Epe, the Netherlands. Both plants obtained the same wastewater and had the same relative hydraulic variations and run stable over time. For the total bacterial population, a similarity analysis was conducted showing that the community composition of both sludge types was very dissimilar. Despite this difference, general bacterial population of both systems had on average comparable species richness, entropy, and evenness, suggesting that different bacteria were sharing the same functionality. Moreover, multi-dimensional scaling analysis revealed that the microbial populations of the flocculent sludge system moved closely around the initial population, whereas the bacterial population in the aerobic granular sludge moved away from its initial population representing a permanent change. In addition, the ammonium-oxidizing community of both sludge systems was studied in detail showing more unevenness than the general bacterial community. Nitrosomonas was the dominant AOB in flocculent sludge, whereas in granular sludge, Nitrosomonas and Nitrosospira were present in equal amounts. A correlation analysis of process data and microbial data from DGGE gels showed that the microbial diversity shift in ammonium-oxidizing bacteria clearly correlated with fluctuations in temperature. PMID:23064482

Winkler, M-K H; Kleerebezem, R; de Bruin, L M M; Verheijen, P J T; Abbas, B; Habermacher, J; van Loosdrecht, M C M

2013-08-01

349

Presence of aerobic micro-organisms and their influence on basic semen parameters in infertile men.  

PubMed

Urogenital tract infections in males are one of the significant etiological factors in infertility. In this prospective study, 72 patients with abnormal semen parameters or any other symptoms of urogenital tract infection were examined. Semen analysis according to the WHO 2010 manual was performed together with microbial assessment: aerobic bacteria culture, Chlamydia antigen test, Candida culture, Ureaplasma and Mycoplasma-specific culture. In total, 69.4% of semen samples were positive for at least one micro-organism. Ureaplasma sp. was the most common micro-organism found in 33% of semen samples of infertile patients with suspected male genital tract infection. The 2nd most common micro-organisms were Enterococcus faecalis (12.5%) and Escherichia coli (12.5%), followed by Staphylococcus aureus (7%), Chlamydia trachomatis (7%) and Candida sp. (5.6%). Generally, bacteria were sensitive to at least one of the antibiotics tested. No statistically significant relationship was observed between the presence of aerobic micro-organisms in semen and basic semen parameters: volume, pH, concentration, total count, motility, vitality and morphology. PMID:25209133

Filipiak, E; Marchlewska, K; Oszukowska, E; Walczak-Jedrzejowska, R; Swierczynska-Cieplucha, A; Kula, K; Slowikowska-Hilczer, J

2014-09-11

350

Bacteria isolated from amoebae/bacteria consortium  

DOEpatents

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, Richard L. (Clinton, TN)

1995-01-01

351

Bacteria isolated from amoebae/bacteria consortium  

DOEpatents

New protozoan derived microbial consortia and method for their isolation are provided. Consortia and bacteria isolated therefrom are useful for treating wastes such as trichloroethylene and trinitrotoluene. Consortia, bacteria isolated therefrom, and dispersants isolated therefrom are useful for dispersing hydrocarbons such as oil, creosote, wax, and grease.

Tyndall, R.L.

1995-05-30

352

Heme and menaquinone induced electron transport in lactic acid bacteria  

PubMed Central

Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. Conclusion We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species. PMID:19480672

Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen

2009-01-01

353

Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 {sup o}C  

SciTech Connect

Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 {sup o}C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 {sup o}C and 55 {sup o}C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH{sub 4}/kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5 L vs. 3-3.5 L CH{sub 4}/kg COD.day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future.

Ferrer, Ivet, E-mail: ivet.ferrer@upc.ed [Environmental Engineering Division, Department of Hydraulic, Maritime and Environmental Engineering. Technical University of Catalonia, C/ Jordi Girona 1-3, E-08034 Barcelona (Spain); Palatsi, Jordi [GIRO Technological Centre, Rambla Pompeu Fabra 1, E-08100 Mollet del Valles, Barcelona (Spain); Campos, Elena [Laboratory of Environmental Engineering, Centre UdL-IRTA, Rovira Roure 191, E-25198 Lleida (Spain); Flotats, Xavier [GIRO Technological Centre, Rambla Pompeu Fabra 1, E-08100 Mollet del Valles, Barcelona (Spain); Department of Agrifood Engineering and Biotechnology, Technical University of Catalonia, Parc Mediterrani de la Tecnologia Edifici D-4, E-08860 Castelldefels, Barcelona (Spain)

2010-10-15

354

Sustainable organic loading rate and energy recovery potential of mesophilic anaerobic membrane bioreactor for municipal wastewater treatment.  

PubMed

The overall performance of a mesophilic anaerobic membrane bioreactor (AnMBR) for synthetic municipal wastewater treatment was investigated under a range of organic loading rate (OLR). A very steady and high chemical oxygen demand (COD) removal (around 98%) was achieved over a broad range of volumetric OLR of 0.8-10 gCOD/L/d. The sustainable volumetric and sludge OLR satisfying a permeate COD below 50 mg/L for general reuse was 6 gCOD/L/d and 0.63 gCOD/gMLVSS (mixed liquor volatile suspended solids)/d, respectively. At a high sludge OLR of over 0.6 gCOD/gMLVSS/d, the AnMBR achieved high methane production of over 300 ml/gCOD (even approaching the theoretical value of 382 ml/gCOD). A low biomass production of 0.015-0.026 gMLVSS/gCOD and a sustainable flux of 6L/m(2)/h were observed. The integration of a heat pump and forward osmosis into the mesophilic AnMBR process would be a promising way for net energy recovery from typical municipal wastewater in a temperate area. PMID:24926606

Wei, Chun-Hai; Harb, Moustapha; Amy, Gary; Hong, Pei-Ying; Leiknes, TorOve

2014-08-01

355

Anaerobic co-digestion of steam-treated Quercus serrata chips and sewage sludge under mesophilic and thermophilic conditions.  

PubMed

The biodegradation of Quercus serrata chips was evaluated by anaerobic digestion under various steam explosion conditions. In continuous experiments, untreated chips (W?) and chips steam-treated at less than 1.0 MPa (W?) and 2.0 MPa (W?) were co-digested with sewage sludge (S? and S?) taken from two different wastewater treatment plants. The apparent methane yield of W? and W? co-digested with S? (thermophilic) was 261 dm(3)/kgVS (volatile solids) and 248 dm(3)/kgVS, respectively. The apparent methane yield of W? co-digested with S? was 258 dm(3)/kgVS (mesophilic) and 271 dm(3)/kgVS (thermophilic). Methane production was inhibited by W? due to components released during hydrolysis. The methane conversion ratio of pretreated chips obtained in batch experiments varied from 40.5% to 53.8% (mesophilic) and from 49.0% to 63.7% (thermophilic). The methane conversion ratio increased with decreasing acid-soluble lignin content in the chips. PMID:24926605

Wang, Feng; Hidaka, Taira; Sakurai, Kensuke; Tsumori, Jun

2014-08-01

356

Identification of trigger factors selecting for polyphosphate- and glycogen-accumulating organisms in aerobic granular sludge sequencing batch reactors.  

PubMed

Nutrient removal performances of sequencing batch reactors using granular sludge for intensified biological wastewater treatment rely on optimal underlying microbial selection. Trigger factors of bacterial selection and nutrient removal were investigated in these novel biofilm systems with specific emphasis on polyphosphate- (PAO) and glycogen-accumulating organisms (GAO) mainly affiliated with Accumulibacter and Competibacter, respectively. In a first dynamic reactor operated with stepwise changes in concentration and ratio of acetate and propionate (Ac/Pr) under anaerobic feeding and aerobic starvation conditions and without wasting sludge periodically, propionate favorably selected for Accumulibacter (35% relative abundance) and stable production of granular biomass. A Plackett-Burman multifactorial experimental design was then used to screen in eight runs of 50 days at stable sludge retention time of 15 days for the main effects of COD concentration, Ac/Pr ratio, COD/P ratio, pH, temperature, and redox conditions during starvation. At 95% confidence level, pH was mainly triggering direct Accumulibacter selection and nutrient removal. The overall PAO/GAO competition in granular sludge was statistically equally impacted by pH, temperature, and redox factors. High Accumulibacter abundances (30-47%), PAO/GAO ratios (2.8-8.4), and phosphorus removal (80-100%) were selected by slightly alkaline (pH > 7.3) and lower mesophilic (<20 °C) conditions, and under full aeration during fixed 2-h starvation. Nitrogen removal by nitrification and denitrification (84-97%) was positively correlated to pH and temperature. In addition to alkalinity, non-limited organic conditions, 3-carbon propionate substrate, sludge age control, and phase length adaptation under alternating aerobic-anoxic conditions during starvation can lead to efficient nutrient-removing granular sludge biofilm systems. PMID:24200006

Weissbrodt, David G; Schneiter, Guillaume S; Fürbringer, Jean-Marie; Holliger, Christof

2013-12-01

357

Can sludge dewatering reactivate microorganisms in mesophilically digested anaerobic sludge? Case of belt filter versus centrifuge.  

PubMed

The anaerobic digestion process that successfully reduces the organic content of sludge is one of the most common alternatives to meet pathogen reduction requirements for particular classes of biosolids. However, recently it was reported that, much higher densities of indicator bacteria were measured in dewatered cake samples compared to samples collected after anaerobic digestion. Additionally, this increase was commonly observed after centrifugation but not after belt filter dewatering. Several hypotheses were tested to explain this occurrence; however, much of the attention was given to the reactivation of the indicator bacteria which might enter a viable but non-culturable state (VBNC) during digestion. The objective of this research is to examine sludge samples from 5 different full-scale treatment plants in order to observe the effect of dewatering processes on the reactivation potential of indicator bacteria. The bacterial enumerations were performed by both Standard Culturing Methods (SCM) and quantitative polymerase chain (qPCR) on samples collected after digestion and dewatering. Results obtained by SCM indicated that in two investigated treatment plants operating belt filter dewatering, an average 0.6 log decrease was observed after the dewatering process. However, 0.7-1.4 log increases were observed immediately after centrifuge dewatering for the other three treatment plants. On the other hand, qPCR results gave 0.1-1.9 log higher numbers compared to SCM. Comparative evaluation of results obtained by two analytical methods for five treatment plants indicates that the differences observed might be originating from both reactivation of VBNC bacteria and amplification of DNA from dead cells found in the sludge. PMID:23141737

Erkan, M; Sanin, F D

2013-01-01

358

Bacteria Inactivation During Lithotripsy  

NASA Astrophysics Data System (ADS)

The influence of extracorporeal and intracorporeal lithotripsy on the viability of bacteria contained inside artificial kidney stones was investigated in vitro. Two different bacteria were exposed to the action of one extracorporeal shock wave generator and four intracorporeal lithotripters.

del Sol Quintero, Marķa; Mora, Ulises; Gutiérrez, Jorge; Mues, Enrique; Castańo, Eduardo; Fernįndez, Francisco; Loske, Achim M.

2006-09-01

359

Bleach vs. Bacteria  

MedlinePLUS

... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

360

Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese.  

PubMed

Four mathematical models were developed and validated for simultaneous growth of mesophilic lactic acid bacteria from added cultures and Listeria monocytogenes, during chilled storage of cottage cheese with fresh- or cultured cream dressing. The mathematical models include the effect of temperature, pH, NaCl, lactic- and sorbic acid and the interaction between these environmental factors. Growth models were developed by combining new and existing cardinal parameter values. Subsequently, the reference growth rate parameters (?ref at 25°C) were fitted to a total of 52 growth rates from cottage cheese to improve model performance. The inhibiting effect of mesophilic lactic acid bacteria from added cultures on growth of L. monocytogenes was efficiently modelled using the Jameson approach. The new models appropriately predicted the maximum population density of L. monocytogenes in cottage cheese. The developed models were successfully validated by using 25 growth rates for L. monocytogenes, 17 growth rates for lactic acid bacteria and a total of 26 growth curves for simultaneous growth of L. monocytogenes and lactic acid bacteria in cottage cheese. These data were used in combination with bias- and accuracy factors and with the concept of acceptable simulation zone. Evaluation of predicted growth rates of L. monocytogenes in cottage cheese with fresh- or cultured cream dressing resulted in bias-factors (Bf) of 1.07-1.10 with corresponding accuracy factor (Af) values of 1.11 to 1.22. Lactic acid bacteria from added starter culture were on average predicted to grow 16% faster than observed (Bf of 1.16 and Af of 1.32) and growth of the diacetyl producing aroma culture was on average predicted 9% slower than observed (Bf of 0.91 and Af of 1.17). The acceptable simulation zone method showed the new models to successfully predict maximum population density of L. monocytogenes when growing together with lactic acid bacteria in cottage cheese. 11 of 13 simulations of L. monocytogenes growth were within the acceptable simulation zone, which demonstrated good performance of the empirical inter-bacterial interaction model. The new set of models can be used to predict simultaneous growth of mesophilic lactic acid bacteria and L. monocytogenes in cottage cheese during chilled storage at constant and dynamic temperatures. The applied methodology is likely to be applicable for safety prediction of other types of fermented and unripened dairy products where inhibition by lactic acid bacteria is important for growth of pathogenic microorganisms. PMID:25086348

Ųstergaard, Nina Bjerre; Eklöw, Annelie; Dalgaard, Paw

2014-10-01

361

cbb3-type cytochrome c oxidases, aerobic respiratory enzymes, impact the anaerobic life of Pseudomonas aeruginosa PAO1.  

PubMed

For bacteria, many studies have focused on the role of respiratory enzymes in energy conservation; however, their effect on cell behavior is poorly understood. Pseudomonas aeruginosa can perform both aerobic respiration and denitrification. Previous studies demonstrated that cbb3-type cytochrome c oxidases that support aerobic respiration are more highly expressed in P. aeruginosa under anoxic conditions than are other aerobic respiratory enzymes. However, little is known about their role under such conditions. In this study, it was shown that cbb3 oxidases of P. aeruginosa PAO1 alter anaerobic growth, the denitrification process, and cell morphology under anoxic conditions. Furthermore, biofilm formation was promoted by the cbb3 oxidases under anoxic conditions. cbb3 oxidases led to the accumulation of nitric oxide (NO), which is produced during denitrification. Cell elongation induced by NO accumulation was reported to be required for robust biofilm formation of P. aeruginosa PAO1 under anoxic conditions. Our data show that cbb3 oxidases promote cell elongation by inducing NO accumulation during the denitrification process, which further leads to robust biofilms. Our findings show that cbb3 oxidases, which have been well studied as aerobic respiratory enzymes, are also involved in denitrification and influence the lifestyle of P. aeruginosa PAO1 under anoxic conditions. PMID:25182494

Hamada, Masakaze; Toyofuku, Masanori; Miyano, Tomoki; Nomura, Nobuhiko

2014-11-01

362

Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.  

PubMed

Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO?-N/L, aerobic P-uptake and oxidation of intercellular poly-?-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO?-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite. PMID:23771179

Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

2014-02-01

363

D/H fractionation in lipids of facultative and obligate denitrifying and sulfate reducing bacteria  

NASA Astrophysics Data System (ADS)

The hydrogen isotopic composition of lipids has been shown to vary broadly in both cultured bacteria and in environmental samples. Culturing studies have indicated that this variability may primarily reflect metabolism; however, the limited number of organisms studied thus far prevents application of these trends to interpretation of environmental samples. Here we report D/H fractionations in anaerobic bacteria, including both facultative and obligate anaerobic organisms with a range of electron donors, acceptors, and metabolic pathways. Experiments using the metabolically flexible alphaproteobacterium Paracoccus denitrificans probe particular central metabolic pathways using a range of terminal electron acceptors. While a large range of ?D values has been observed during aerobic metabolism, denitrifying cultures produce a more limited range in ?D values that are more similar to each other than the corresponding aerobic culture. Data from the sulfate reducing bacteria Desulfobacterium autotrophicum and Desulfobacter hydrogenophilus indicate that chemolithoautotrophy and anaerobic heterotrophy can produce similar ?D values, and are similar between bacteria despite differing metabolic pathways. These results suggest that the fractionation of D/H depends both on the specific metabolic pathway and the electron acceptor. While this is not inconsistent with previous studies, it suggests the simple correspondence between ?D and metabolism previously understood from aerobic bacteria is not universally applicable.

Osburn, M. R.; Sessions, A. L.

2012-12-01

364

Communication in Bacteria  

Microsoft Academic Search

Bacteria communicate with one another using chemical signal molecules. As in higher organisms, the information supplied by these molecules is critical for synchronizing the activities of large groups of cells. In bacteria, chemical communication involves producing, re- leasing, detecting, and responding to small hormone-like molecules termed autoinducers. This process, termed quorum sensing, allows bacteria to monitor the environment for other

Christopher M. Waters; Bonnie L. Bassler

365

CHAPTER IV-2 BACTERIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Entomopathogenic bacteria provide an alternative to chemical pesticides used in insect control programs. Today, the principal microbial insecticides utilize spore forming bacteria or toxins produced by these bacteria as their active ingredients, either in formulations or by incorporation of toxin g...

366

Mathematical modeling of aerobic granular sludge: a review.  

PubMed

Aerobic granulation may play an important role in the field of wastewater treatment due to the advantages of aerobic granules compared to the conventional sludge flocs, such as denser structure, better settleability and ensured solid-effluent separation, higher biomass concentration, and greater ability to withstand shock loadings, which is promising for a full-scale implementation. As an aid for this implementation, mathematical modeling would be an invaluable tool. In this paper, the existing mathematical models available in literature concerning aerobic granule systems are reviewed, including the modeling of the dynamic facets of the aerobic granulation process, the mass transfer and detachment in aerobic granules, the granule-based sequencing batch reactor, the fate of microbial products in granules, and the multi-scale modeling of aerobic granular sludge. An overview of the parameters used in the aerobic granular modeling approaches is also presented. Our growing knowledge on mathematical modeling of aerobic granule might facilitate the engineering and optimization of aerobic granular sludge technology as one of the most promising techniques in the biological wastewater treatment. PMID:20728529

Ni, Bing-Jie; Yu, Han-Qing

2010-01-01

367

Self-Assembling Amphiphilic Siderophores from Marine Bacteria  

NASA Astrophysics Data System (ADS)

Most aerobic bacteria secrete siderophores to facilitate iron acquisition. Two families of siderophores were isolated from strains belonging to two different genera of marine bacteria. The aquachelins, from Halomonas aquamarina strain DS40M3, and the marinobactins, from Marinobacter sp. strains DS40M6 and DS40M8, each contain a unique peptidic head group that coordinates iron(III) and an appendage of one of a series of fatty acid moieties. These siderophores have low critical micelle concentrations (CMCs). In the absence of iron, the marinobactins are present as micelles at concentrations exceeding their CMC; upon addition of iron(III), the micelles undergo a spontaneous phase change to form vesicles. These observations suggest that unique iron acquisition mechanisms may have evolved in marine bacteria.

Martinez, J. S.; Zhang, G. P.; Holt, P. D.; Jung, H.-T.; Carrano, C. J.; Haygood, M. G.; Butler, Alison

2000-02-01

368

Biotransformation of phytosterols under aerobic conditions.  

PubMed

Phytosterols are plant-derived sterols present in pulp and paper wastewater and have been implicated in the endocrine disruption of aquatic species. Bioassays were performed to assess the effect of an additional carbon source and/or solubilizing agent on the aerobic biotransformation of a mixture of three common phytosterols (?-sitosterol, stigmasterol and campesterol). The aerobic biotransformation of the phytosterol mixture by a mixed culture developed from a pulp and paper wastewater treatment system was examined under three separate conditions: with phytosterols as the sole added carbon source, with phytosterols and dextrin as an additional carbon source, and with phytosterols added with ethanol as an additional carbon source and solubilizing agent. Significant phytosterol removal was not observed in assays set up with phytosterol powder, either with or without an additional carbon source. In contrast, all three phytosterols were aerobically degraded when added as a dissolved solution in ethanol. Thus, under the experimental conditions of this study, the bioavailability of phytosterols was limited without the presence of a solubilizing agent. The total phytosterol removal rate was linear for the first six days before re-spiking, with a rate of 0.47 mg/L-d (R(2) = 0.998). After the second spiking, the total phytosterol removal rate was linear for seven days, with a rate of 0.32 mg/L-d (R(2) = 0.968). Following the 7th day, the phytosterol removal rate markedly accelerated, suggesting two different mechanisms are involved in phytosterol biotransformation, more likely related to the production of enzyme(s) involved in phytosterol degradation, induced under different cell growth conditions. ?-sitosterol was preferentially degraded, as compared to stigmasterol and campesterol, although all three phytosterols fell below detection limits by the 24th day of incubation. PMID:24747138

Dykstra, Christy M; Giles, Hamilton D; Banerjee, Sujit; Pavlostathis, Spyros G

2014-07-01

369

Bacteria Are Everywhere!  

NSDL National Science Digital Library

Students are introduced to the concept of engineering biological organisms and studying their growth to be able to identify periods of fast and slow growth. They learn that bacteria are found everywhere, including on the surfaces of our hands. Student groups study three different conditions under which bacteria are found and compare the growth of the individual bacteria from each source. In addition to monitoring the quantity of bacteria from differ conditions, they record the growth of bacteria over time, which is an excellent tool to study binary fission and the reproduction of unicellular organisms.

AMPS GK-12 Program,

370

Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors  

PubMed Central

This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m?3·d?1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

2014-01-01

371

Nitrogen removal over nitrite by aeration control in aerobic granular sludge sequencing batch reactors.  

PubMed

This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m-3·d-1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

2014-07-01

372

Induced cooperation between marine nitrifiers and anaerobic ammonium-oxidizing bacteria by incremental exposure to oxygen.  

PubMed

In oxygen-limited marine ecosystems cooperation between marine nitrifiers and anaerobic ammonium-oxidizing (anammox) bacteria is of importance to nitrogen cycling. Strong evidence for cooperation between anammox bacteria and nitrifiers has been provided by environmental studies but little is known about the development of such communities, the effects of environmental parameters and the physiological traits of their constituents. In this study, a marine laboratory model system was developed. Cooperation between marine nitrifiers and anammox bacteria was induced by incremental exposure of a marine anammox community dominated by Scalindua species to oxygen in a bioreactor set-up under high ammonium (40 mM influent) conditions. Changes in the activities of the relevant functional groups (anammox bacteria, aerobic ammonia oxidizers and nitrite oxidizers) were monitored by batch tests. Changes in community composition were followed by Fluorescence in situ Hybridization (FISH) and by amplification and sequencing of 16S rRNA and amoA genes. A co-culture of Scalindua sp., an aerobic ammonia-oxidizing Nitrosomonas-like species, and an aerobic (most likely Nitrospira sp.) nitrite oxidizer was obtained. Aerobic ammonia oxidizers became active immediately upon exposure to oxygen and their numbers increased 60-fold. Crenarchaea closely related to the ammonia-oxidizer Candidatus 'Nitrosopumilus maritimus' were detected in very low numbers and their contribution to nitrification was assumed negligible. Activity of anammox bacteria was not inhibited by the increased oxygen availability. The developed marine model system proved an effective tool to study the interactions between marine anammox bacteria and nitrifiers and their responses to changes in environmentally relevant conditions. PMID:20956064

Yan, Jia; Op den Camp, Huub J M; Jetten, Mike S M; Hu, Yong Y; Haaijer, Suzanne C M

2010-11-01

373

Effect of solvents on obligately anaerobic bacteria.  

PubMed

Growth of Acetobacterium woodii and Clostridium sporogenes was studied in the presence of water-immiscible solvents. Nitrogen purging, vacuum distillation or distillation under nitrogen were all suitable as methods to remove oxygen from the solvents, since growth rates and yields of A. woodii were unaffected in the presence of tetradecane which had been degassed by these methods. Varying the solvent volume from 20% to 80% of the culture volume had little effect on growth rate of A. woodii. A.woodii was relatively sensitive to organic solvents since growth was inhibited by alkanes with logP(octanol/water) values below 7.1. C. sporogenes was less solvent sensitive, since it grew without inhibition when the logP of the solvent was > or = 6.6. Nevertheless, both A. woodii and C. sporogenes were more sensitive to solvent polarity than aerobic bacteria. PMID:18083050

Rodriguez Martinez, Maria Fernanda; Kelessidou, Niki; Law, Zoe; Gardiner, John; Stephens, Gill

2008-02-01

374

Toxicity effect of phenol on aerobic granules.  

PubMed

Aerobic granular sludge cultivated in a pilot-scale sequencing batch reactor, through mechanical separation using metal sieves, was categorized into five size categories of0.09 (flocs), 0.35, 0.82, 1.65 and 2.54 mm in mean diameter. Granule microbial activiy of each size category and the activity of the sludge flocs were determined after exposure to phenol (0-3000 mg L(-1)) at various exposure times of 4, 12, and 24 hours. The microbial activity reduction follows a linear relationship with the increase in phenol concentration for both granules and sludge flocs. The C50 value, i.e., the phenol concentration causing 50% inhibition of the microbial activity, decreased significantly with the exposure time, but it increased with granule size. The C50 increased by 18% from 1273 mg L(-1) for sludge flocs to 1497 mg L(-1) for granules of size 2.54 mm at an exposure time of 24 hours. The results indicated that the granular structure could protect the microbial cells from phenol toxicity. The application of aerobic granules in wastewater treatment could provide an improved ability to tolerate toxic chemical shock, particularly at longer exposure times. PMID:19213468

Liu, Q S; Liu, Y; Show, K Y; Tay, J H

2009-01-01

375

The primary aerobic biodegradation of gasoline hydrocarbons.  

PubMed

We describe the primary aerobic biodegradation of an unleaded, unoxygenated, regular gasoline by inocula from unacclimated fresh and sea water, and from a domestic sewage treatment plant. Biodegradation was rapid and complete in all inocula, with an overall median "half-life", at approximately 70 ppm gasoline and low levels of inorganic nutrients, of 5 days. The biodegradation of 131 individual hydrocarbons in the gasoline followed a relatively consistent pattern. The larger n-alkanes and iso-alkanes, and simple and alkylated aromatic compounds were the most readily degraded compounds, followed by the smaller n-alkanes and isoalkanes and the naphthenes. The last compounds to be degraded were butane, iso-butane, and 2,2-dimethylbutane, but even these disappeared with an apparent half-life of <30 days. The fact that the aqueous concentration of many of the individual components was in the sub ppb level is a remarkable demonstration of the ability of unadapted indigenous aerobic microorganisms to respond to and effectively biodegrade gasoline range hydrocarbons. PMID:17539543

Prince, Roger C; Parkerton, Thomas F; Lee, Carolyn

2007-05-01

376

Characterization and aerobic biodegradation of selected monoterpenes  

SciTech Connect

Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M. [Georgia Institute of Technology, Atlanta, GA (United States)

1996-12-31

377

Microbial Removal of Atmospheric Carbon Tetrachloride in Bulk Aerobic Soils?  

PubMed Central

Atmospheric concentrations of carbon tetrachloride (CCl4) were removed by bulk aerobic soils from tropical, subtropical, and boreal environments. Removal was observed in all tested soil types, indicating that the process was widespread. The flux measured in field chamber experiments was 0.24 ± 0.10 nmol CCl4 (m2 day)?1 (average ± standard deviation [SD]; n = 282). Removal of CCl4 and removal of methane (CH4) were compared to explore whether the two processes were linked. Removal of both gases was halted in laboratory samples that were autoclaved, dry heated, or incubated in the presence of mercuric chloride (HgCl2). In marl soils, treatment with antibiotics such as tetracycline and streptomycin caused partial inhibition of CCl4 (50%) and CH4 (76%) removal, but removal was not affected in soils treated with nystatin or myxothiazol. These data indicated that bacteria contributed to the soil removal of CCl4 and that microeukaryotes may not have played a significant role. Amendments of methanol, acetate, and succinate to soil samples enhanced CCl4 removal by 59%, 293%, and 72%, respectively. Additions of a variety of inhibitors and substrates indicated that nitrification, methanogenesis, or biological reduction of nitrate, nitrous oxide, or sulfate (e.g., occurring in possible anoxic microzones) did not play a significant role in the removal of CCl4. Methyl fluoride inhibited removal of CH4 but not CCl4, indicating that CH4 and CCl4 removals were not directly linked. Furthermore, CCl4 removal was not affected in soils amended with copper sulfate or methane, supporting the results with MeF and suggesting that the observed CCl4 removal was not significantly mediated by methanotrophs. PMID:21724884

Mendoza, Y.; Goodwin, K. D.; Happell, J. D.

2011-01-01

378

Sexual Dimorphism in Primate Aerobic Capacity: A Phylogenetic Test  

PubMed Central

Male intrasexual competition should favour increased male physical prowess. This should in turn result in greater aerobic capacity in males than in females (i.e., sexual dimorphism), and a correlation between sexual dimorphism in aerobic capacity and the strength of sexual selection among species. However, physiological scaling laws predict that aerobic capacity should be lower per unit body mass in larger than in smaller animals, potentially reducing or reversing the sex difference and its association with measures of sexual selection. We used measures of hematocrit and red blood cell (RBC) counts from 45 species of primates to test four predictions related to sexual selection and body mass: (i) on average, males should have higher aerobic capacity than females, (ii) aerobic capacity should be higher in adult than juvenile males, (iii) aerobic capacity should increase with increasing sexual selection, but also that (iv) measures of aerobic capacity should covary negatively with body mass. For the first two predictions we used a phylogenetic paired t-test developed for this study. We found support for predictions (i) and (ii). For prediction (iii), however, we found a negative correlation between the degree of sexual selection and aerobic capacity, which was opposite to our prediction. Prediction (iv) was generally supported. We also investigated whether substrate use, basal metabolic rate, and agility influenced physiological measures of oxygen transport, but we found only weak evidence for a correlation between RBC count and agility. PMID:20406346

Lindenfors, Patrik; Revell, Liam J.; Nunn, Charles L.

2010-01-01

379

The Effectiveness of Aerobic Exercise Instruction for Totally Blind Women.  

ERIC Educational Resources Information Center

A multifaceted method (involving verbal and hands-on training) was used to teach aerobic exercises to 3 totally blind women (ages 24-37). All three women demonstrated positive gains in their performance, physical fitness, and attitudes toward participating in future mainstream aerobic exercise classes. (DB)

Ponchillia, S. V.; And Others

1992-01-01

380

Water aerobics in pregnancy: cardiovascular response, labor and neonatal outcomes  

Microsoft Academic Search

BACKGROUND: To evaluate the association between water aerobics, maternal cardiovascular capacity during pregnancy, labor and neonatal outcomes. METHODS: A randomized, controlled clinical trial was carried out in which 34 pregnant women were allocated to a water aerobics group and 37 to a control group. All women were submitted to submaximal ergometric tests on a treadmill at 19, 25 and 35

Erica P Baciuk; Rosa I Pereira; Jose G Cecatti; Angelica F Braga; Sergio R Cavalcante

2008-01-01

381

Characterization and evaluation of aerobic granules in sequencing batch reactor  

Microsoft Academic Search

In order to investigate the aerobic granules cultured under alternating aerobic and anoxic conditions, a sequencing batch reactor (SBR) was operated without the presence of a carrier material. Nitrification and denitrification occurred alternately in the SBR operation, with an increased nitrification efficiency of up to 97% and a high chemical oxygen demand (COD) removal efficiency of up to 95%. It

Am Jang; Young-Han Yoon; In S. Kim; Kwang-Soo Kim; Paul L. Bishop

2003-01-01

382

Modelling of moisture-dependent aerobic degradation of solid waste  

Microsoft Academic Search

In landfill, high temperature levels come from aerobic reactions inside the waste surface layer. They are known to make anaerobic processes more reliable, by partial removal of easily biodegradable substrates. Aerobic biodegradation of the main components of biodegradable matter (paper and cardboard waste, food and yard waste) is considered. In this paper, two models which take into account the effect

S. Pommier; D. Chenu; M. Quintard; X. Lefebvre

2008-01-01

383

ORIGINAL PAPER Characterization of multiple novel aerobic polychlorinated  

E-print Network

ORIGINAL PAPER Characterization of multiple novel aerobic polychlorinated biphenyl (PCB of bioremediation as an effective tool for cleanup of PCB-contaminated soils. Keywords Aerobic biodegradation Ɓ and Sciences, Indiana University, Bloomington, IN 47405, USA 123 Biodegradation (2008) 19:145Ā­159 DOI 10.1007/s

Craft, Christopher B.

384

Inhibition of aerobic respiration and dissimilatory perchlorate reduction using cyanide  

E-print Network

Inhibition of aerobic respiration and dissimilatory perchlorate reduction using cyanide Yanguang reduction and aerobic respiration was examined using pure cultures of Azospira sp. KJ. Cyanide reduction; Respiration pathway 1. Introduction Perchlorate (ClOĆ? 4 ) has been detected in impacted ground

385

Bacillus acidicola sp. nov., a novel mesophilic, acidophilic species isolated from acidic Sphagnum peat bogs in Wisconsin.  

PubMed

A mesophilic, acidophilic, spore-forming bacterium, strain 105-2(T), was isolated from an acidic Sphagnum peat bog in Wisconsin, USA. Strain 105-2(T) has 16S rRNA gene sequence similarity to Bacillus sporothermodurans DSM 10599(T) and Bacillus oleronius DSM 9356(T) of 97.4 and 97.8%, respectively. The primary lipoquinone is MK-7 and the major fatty acids are 15:0 iso, 15:0 anteiso and 17:0 anteiso. The predominant polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and a glycolipid. The DNA G+C content was found to be 43.2 mol%. The phenotypic, chemotaxonomic and molecular analyses identified strain 105-2(T) as a novel Bacillus species, for which the name Bacillus acidicola is proposed. The type strain is 105-2(T) (=DSM 14745(T)=ATCC BAA-366(T)=NRRL B-23453(T)). PMID:16166720

Albert, Richard A; Archambault, Julieta; Rosselló-Mora, Ramón; Tindall, Brian J; Matheny, Mike

2005-09-01

386

Cereulide formation by Bacillus weihenstephanensis and mesophilic emetic Bacillus cereus at temperature abuse depends on pre-incubation conditions.  

PubMed

Emetic toxin (cereulide) formation was recently identified in a psychrotolerant species, Bacillus weihenstephanensis [Thorsen, L., Hansen, B.M., Nielsen, K.F., Hendriksen, N.B., Phipps, R.K., Budde, B.B., 2006. Characterization of emetic Bacillus weihenstephanensisis, a new cereulide-producing bacterium. Applied and Environmental Microbiology, 72, 5118-5121.]. Although recent findings indicated B. weihenstephanensis as a cereulide producer only limited information is available regarding environmental conditions affecting cereulide production. In the present study a model agar system was used to compare cereulide production during surface growth of B. weihenstephanensis MC67, and two well known mesophilic cereulide producing Bacillus cereus strains, NC7401 and NS117. Cereulide production was quantified by use of Liquid-Chromatography Mass Spectrometry/Mass Spectrometry. Cereulide production of B. weihenstephanensis MC67 occurred in stationary growth phase, as previously observed for B. cereus, and biomass formation and cereulide formation showed a linear correlation. During incubation at 5 degrees C for 1, 2 and 3 weeks growth was inhibited and as a consequence no detectable cereulide production occurred for any of the three strains. Similar results were obtained for the mesophilic B. cereus strains when incubated at 8 degrees C, whereas B. weihenstephanensis MC67 grew to stationary phase and produced 0.002 microg cereulide/cm(2) agar surface in 1 week. Raising the temperature from 5 degrees C to 25 degrees C for 24 h after 1 week of incubation resulted in growth to stationary phase and production of variable levels of cereulide. B. weihenstephanensis MC67 produced 6.18 microg cereulide/cm(2), B. cereus NS117 0.91 microg cereulide/cm(2) and B. cereus NC7401 0.09 microg cereulide/cm(2). Similar levels of cereulide was produced by the mesophilic strains when raising the temperature from 8 degrees C (instead of from 5 degrees C) to 25 degrees C for 24 h, while a considerably lower level was produced by B. weihenstephanensis MC67 (0.10 microg cereulide /cm(2)). If the temperature was raised from 5 degrees C and 8 degrees C to 25 degrees C for 24 h after an increased incubation time for 2 and 3 weeks, all three strains produced considerably less cereulide. B. weihenstephanensis MC67 produced 100-6000 times less and the mesophilic B. cereus strains produced 9-40 times less cereulide. These results can partly be explained by differences in the growth at the temperature abuse. Effect of chill storage on cereulide production at temperature abuse has not been investigated previously. Results of the present study indicate that storage at 5 and 8 degrees C will not lead to emetic intoxications, however the time at, and choice of chill temperature will determine the amount of cereulide produced in a temperature abuse situation. These results are of relevance for the safety of chilled foods of extended durability. PMID:19428136

Thorsen, Line; Budde, Birgitte Bjųrn; Henrichsen, Lars; Martinussen, Torben; Jakobsen, Mogens

2009-08-31

387

Progressive Degradation of Crude Oil n-Alkanes Coupled to Methane Production under Mesophilic and Thermophilic Conditions  

PubMed Central

Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus) and Firmicutes (mainly consisting of Desulfotomaculum) were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, “Shengli Cluster” and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes. PMID:25409013

Cheng, Lei; Shi, Shengbao; Li, Qiang; Chen, Jianfa; Zhang, Hui; Lu, Yahai

2014-01-01

388

"Hot cores" in proteins: Comparative analysis of the apolar contact area in structures from hyper/thermophilic and mesophilic organisms  

PubMed Central

Background A wide variety of stabilizing factors have been invoked so far to elucidate the structural basis of protein thermostability. These include, amongst the others, a higher number of ion-pairs interactions and hydrogen bonds, together with a better packing of hydrophobic residues. It has been frequently observed that packing of hydrophobic side chains is improved in hyperthermophilic proteins, when compared to their mesophilic counterparts. In this work, protein crystal structures from hyper/thermophilic organisms and their mesophilic homologs have been compared, in order to quantify the difference of apolar contact area and to assess the role played by the hydrophobic contacts in the stabilization of the protein core, at high temperatures. Results The construction of two datasets was carried out so as to satisfy several restrictive criteria, such as minimum redundancy, resolution and R-value thresholds and lack of any structural defect in the collected structures. This approach allowed to quantify with relatively high precision the apolar contact area between interacting residues, reducing the uncertainty due to the position of atoms in the crystal structures, the redundancy of data and the size of the dataset. To identify the common core regions of these proteins, the study was focused on segments that conserve a similar main chain conformation in the structures analyzed, excluding the intervening regions whose structure differs markedly. The results indicated that hyperthermophilic proteins underwent a significant increase of the hydrophobic contact area contributed by those residues composing the alpha-helices of the structurally conserved regions. Conclusion This study indicates the decreased flexibility of alpha-helices in proteins core as a major factor contributing to the enhanced termostability of a number of hyperthermophilic proteins. This effect, in turn, may be due to an increased number of buried methyl groups in the protein core and/or a better packing of alpha-helices with the rest of the structure, caused by the presence of hydrophobic beta-branched side chains. PMID:18312638

Paiardini, Alessandro; Sali, Riccardo; Bossa, Francesco; Pascarella, Stefano

2008-01-01

389

The backbone structure of the thermophilic Thermoanaerobacter tengcongensis ribose binding protein is essentially identical to its mesophilic E. coli homolog  

PubMed Central

Background Comparison of experimentally determined mesophilic and thermophilic homologous protein structures is an important tool for understanding the mechanisms that contribute to thermal stability. Of particular interest are pairs of homologous structures that are structurally very similar, but differ significantly in thermal stability. Results We report the X-ray crystal structure of a Thermoanaerobacter tengcongensis ribose binding protein (tteRBP) determined to 1.9 Å resolution. We find that tteRBP is significantly more stable (appTm value ~102°C) than the mesophilic Escherichia coli ribose binding protein (ecRBP) (appTm value ~56°C). The tteRBP has essentially the identical backbone conformation (0.41 Å RMSD of 235/271 C? positions and 0.65 Å RMSD of 270/271 C? positions) as ecRBP. Classification of the amino acid substitutions as a function of structure therefore allows the identification of amino acids which potentially contribute to the observed thermal stability of tteRBP in the absence of large structural heterogeneities. Conclusion The near identity of backbone structures of this pair of proteins entails that the significant differences in their thermal stabilities are encoded exclusively by the identity of the amino acid side-chains. Furthermore, the degree of sequence divergence is strongly correlated with structure; with a high degree of conservation in the core progressing to increased diversity in the boundary and surface regions. Different factors that may possibly contribute to thermal stability appear to be differentially encoded in each of these regions of the protein. The tteRBP/ecRBP pair therefore offers an opportunity to dissect contributions to thermal stability by side-chains alone in the absence of large structural differences. PMID:18373848

Cuneo, Matthew J; Tian, Yaji; Allert, Malin; Hellinga, Homme W

2008-01-01

390

[Start-up, formation and microbial community analysis of aerobic granules in SABR for treatment of organic wastewater containing aniline and chloroanilines].  

PubMed

The granulation of aerobic sludges for high-rate biodegradation of organic wastewater containing aniline and chloroanilines was investigated in a laboratory-scale sequencing airlift bioreactor ( SABR). Aerobic granules were observed in 15 days after start-up in SABR. After subsequent 83 days, SABR was operated sequentially in superficial air velocity of 2.4cm/s, COD loadings of 1.0-3.6kg/(m3 x d) and (chloro-) anilines loadings increased stepwise to 1kg/(m3 x d), a steady-state performance of aerobic granular SABR was achieved at last, as evidenced by high and stable COD and (chloro-) anilines removal efficiencies of above 90% and 99.9%, respectively. Mature granules with median size of 0.45-2.5mm, minimal settling velocity of 62. 1m/h, and SVI of 56mL/g were developed. Aerobic granular sludge displayed noteworthy SOUR, specific (chloro-) anilines degradation rates, PN content and PN/PS ratio in EPS extracts as 154mgDO/(gVSS x h), 0.18g/(gVSS x d), 28.0 +/- 1.9mg/gVSS and 6.5mg/mg respectively, indicating that they had high activity and ability to withstand high (chloro-) anilines loadings. Phylogenetic analysis of (chloro-) anilines-degrading aerobic granules indicated that beta-, gamma-Proteobacteria and Flavobacteria were dominant classes and the predominance bacteria were closely related to Pseudomonas sp. and Flavo-bacterium sp. Compared to chloroanilines-degrading aerobic granules, the population diversity was higher in the aniline and chloroaniline-degrading aerobic granules. PMID:17944367

Zhu, Liang; Xu, Xiang-yang; Cao, Dan-feng; Luo, Wei-guo; Yang, Yan-ni

2007-08-01

391

Aerobic ammonium oxidation in the oxycline and oxygen minimum zone of the eastern tropical South Pacific off northern Chile (˜20°S)  

NASA Astrophysics Data System (ADS)

Aerobic NH 4+ oxidation rates were measured along the strong oxygen gradient associated with the oxygen minimum zone (OMZ) of the eastern tropical South Pacific off northern Chile (˜20°S) during 2000, 2003, and 2004. This process was examined by comparing NH 4+ rates of change during dark incubations, with and without the addition of allylthiourea, a classical inhibitor of the ammonia monooxygenase enzyme of ammonium-oxidizing bacteria. The contribution of aerobic NH 4+ oxidation in dark carbon fixation and NO 2- rates of change were also explored. Thirteen samples were retrieved from the oxycline (252 to ?5 ?M O 2; 15 to ˜65 m depth) and three from the oxygen minimum core (?5 ?M O 2; 100-200 m depth). Aerobic NH 4+ oxidation rates were mainly detected in the upper part (15-30 m depth) of the oxycline, with rates ranging from 0.16 to 0.79 ?M d -1, but not towards the oxycline base (40-65 m depth). In the oxygen minimum core, aerobic NH 4+ oxidation was in the upper range and higher than in the upper part of the oxycline (0.70 and 1.0 ?M d -1). Carbon fixation rates through aerobic NH 4+ oxidation ranged from 0.18 to 0.43 ?g C L -1 d -1 and contributed between 33% and 57% of the total dark carbon fixation, mainly towards the oxycline base and, in a single experiment, in the upper part of the oxycline. NO 2- consumption was high (up to 10 ?M d -1) towards the oxycline base and OMZ core, but was significantly reduced in experiments amended with allylthiourea, indicating that aerobic NH 4+ oxidation could contribute between 8% and 76% of NO 2- production, which in turn could be available for denitrifiers. Overall, these results support the important role of aerobic NH 4+ oxidizers in the nitrogen and carbon cycling in the OMZ and at its upper boundary.

Molina, Verónica; Farķas, Laura

2009-07-01

392

The intracellular bacteria Chlamydia hijack peroxisomes and utilize their enzymatic capacity to produce bacteria-specific phospholipids.  

PubMed

Chlamydia trachomatis is an obligate intracellular pathogen responsible for loss of eyesight through trachoma and for millions of cases annually of sexually transmitted diseases. The bacteria develop within a membrane-bounded inclusion. They lack enzymes for several biosynthetic pathways, including those to make some phospholipids, and exploit their host to compensate. Three-dimensional fluorescence microscopy demonstrates that small organelles of the host, peroxisomes, are translocated into the Chlamydia inclusion and are found adjacent to the bacteria. In cells deficient for peroxisome biogenesis the bacteria are able to multiply and give rise to infectious progeny, demonstrating that peroxisomes are not essential for bacterial development in vitro. Mass spectrometry-based lipidomics reveal the presence in C. trachomatis of plasmalogens, ether phospholipids whose synthesis begins in peroxisomes and have never been described in aerobic bacteria before. Some of the bacterial plasmalogens are novel structures containing bacteria-specific odd-chain fatty acids; they are not made in uninfected cells nor in peroxisome-deficient cells. Their biosynthesis is thus accomplished by the metabolic collaboration of peroxisomes and bacteria. PMID:24465954

Boncompain, Gaelle; Müller, Constanze; Meas-Yedid, Vannary; Schmitt-Kopplin, Philippe; Lazarow, Paul B; Subtil, Agathe

2014-01-01

393

[Distribution of potentially nitrogen-fixing bacteria and its relationship with physicochemical parameters in soils with three vegetation types in the southern Colombian Amazon region].  

PubMed

Potentially nitrogen-fixing microaerobic and aerobic bacteria were isolated from several Colombian Amazon soils (forest, pastures and chagras) and two landscapes (floodable and non floodable areas). The abundance and distribution of bacteria were evaluated, as well as their relationship with soil physical and chemical characteristics. Landscape had a direct influence on the abundance of the microaerobic bacteria, with higher numbers in forest and pasture soils in non-floodable zones. The aerobic isolates (N=51) were grouped into 19 morphologies, with the highest numbers found in forest soil in floodable zones. A higher number of aerobic morphologies was shared among forest sites (Nonmetric Multidimensional Scaling and Analysis of Similarity p<0.05), and 40% of the distribution was explained by lime percentage and Al concentration. PMID:20073324

Mantilla-Paredes, Andrea J; Cardona, Gladys I; Peńa-Venegas, Clara P; Murcia, Uriel; Rodrķguez, Mariana; Zambrano, Maria M

2009-12-01

394

The Photosynthetic Apparatus and Its Regulation in the Aerobic Gammaproteobacterium Congregibacter litoralis gen. nov., sp. nov  

PubMed Central

Background There is accumulating evidence that in some marine environments aerobic bacteriochlorophyll a-producing bacteria represent a significant part of the microbial population. The interaction of photosynthesis and carbon metabolism in these interesting bacteria is still largely unknown and requires further investigation in order to estimate their contribution to the marine carbon cycle. Methodology/Principal Findings Here, we analyzed the structure, composition and regulation of the photosynthetic apparatus in the obligately aerobic marine gammaproteobacterium KT71T. Photoheterotrophically grown cells were characterized by a poorly developed lamellar intracytoplasmic membrane system, a type 1 light-harvesting antenna complex and a photosynthetic reaction center associated with a tetraheme cytochrome c. The only photosynthetic pigments produced were bacteriochlorophyll a and spirilloxanthin. Under semiaerobic conditions KT71T cells expressing a photosynthetic apparatus showed a light-dependent increase of growth yield in the range of 1.3–2.5 fold. The expression level of the photosynthetic apparatus depended largely on the utilized substrate, the intermediary carbon metabolism and oxygen tension. In addition, pigment synthesis was strongly influenced by light, with blue light exerting the most significant effect, implicating that proteins containing a BLUF domain may be involved in regulation of the photosynthetic apparatus. Several phenotypic traits in KT71T could be identified that correlated with the assumed redox state of growing cells and thus could be used to monitor the cellular redox state under various incubation conditions. Conclusions/Significance In a hypothetical model that explains the regulation of the photosynthetic apparatus in strain KT71T we propose that the expression of photosynthesis genes depends on the cellular redox state and is maximal under conditions that allow a balanced membrane redox state. So far, bacteria capable of an obligately aerobic, photosynthetic metabolism constitute a unique phenotype within the class Gammaproteobacteria, so that it is justified to propose a new genus and species, Congregibacter litoralis gen. nov, sp. nov., represented by the type strain KT71T (?=?DSM 17192T?=?NBRC 104960T). PMID:19287491

Spring, Stefan; Lünsdorf, Heinrich; Fuchs, Bernhard M.; Tindall, Brian J.

2009-01-01

395

Bacteria TMDL Projects  

E-print Network

of the projects are listed below. ? Peach CreekWater Quality Improvement Project ? Monitoring and Educational Programs Focused on Bacteria and Nutrient Runoff on Dairy Operations in the LeonWatershed ? Development of the Plum CreekWPP ? Impact of Proper... Star Healthy Streams * ? Environmental Management of Grazing Lands * *TWRI-managed projects More information on the initiative is available at www.tsswcb.state.tx.us/managementprogram/ initiatives/bacteria. Bacteria Projects Across the State...

Wythe, Kathy

2007-01-01

396

Introduction to Bacteria  

NSDL National Science Digital Library

This science site has students research how bacteria move, where they live, and how they reproduce; learn how bacteria can be helpful or harmful; and create a design illustrating what they have learned about bacteria. Included in the lesson plan are the objectives, needed materials and Web sites, procedures, discussion questions, evaluation, extensions, suggested reading, and vocabulary. Teachers can link to Teaching Tools to create custom worksheets, puzzles, and quizzes. A printable version of the lesson plan can be downloaded. The video Bacteria, Viruses and Allergies can be purchased and comprehension questions and answers can be downloaded.

Discoveryschool.com; Fenichel, Marilyn

2007-12-12

397

Effects of humic substances on the bioavailability and aerobic biodegradation of polychlorinated biphenyls in a model soil.  

PubMed

The very high hydrophobicity of polychlorinated biphenyls (PCBs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradability of PCBs in heavily contaminated soils can be significantly enhanced by soil treatment with surface-active agents. In this work, the effects of naturally occurring surfactants such as humic substances (HS) on the aerobic biodegradation of PCBs in a model soil were studied. The soil was amended with biphenyl (4 g/kg), Fenclor 42 (1,000 mg/kg), the aerobic PCB-biodegrading bacterial co-culture ECO3 (inoculum: 10(8)CFU/mL), and treated in aerobic batch slurry-phase conditions (17.5% w/v) with and without the addition of HS at the rates of 1.5 and 3.0% (w/w). Low PCBs biodegradation and dechlorination yields were observed in the HS-free microcosms, probably as a result of the rapid disappearance of inoculated bacteria. The presence of HS influenced significantly the activity of the specialized biomass and the biodegradation of PCBs in the microcosms. The microcosms that received HS at the 1.5% rate showed a higher persistence of the specialized bacteria and yields of PCB biodegradation and dechlorination about 150 and 100%, respectively, larger than those found for the HS-free microcosms. Lower stimulating effects were observed in the microcosms added with the HS at 3.0% rate. These effects were attributed to an increased solubilization of PCBs in the hydrophobic domains of the humic supramolecular associations and to a different accessibility of PCBs by the specialized bacteria at the different rates of HS addition. Although the slurry-phase treatment generally showed a decrease of the original soil ecotoxicity, the addition of the originally non-toxic HS decreased soil ecotoxicity for the Collembola animal biomarker and increased that towards the Lepidium sativum vegetal biomarker. PMID:11753927

Fava, Fabio; Piccolo, Alessandro

2002-01-20

398

Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates  

NASA Astrophysics Data System (ADS)

A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (?13C - 5.2 to - 10.9‰) compared to groundwater (?13C - 39.5‰) at the on-site location. Soil gas CO2 isotope analysis at both locations showed that CO2 was highly isotopically depleted (?13C - 28.8 to - 33.3‰), compared to soil gas CO2 data originating from natural sediment organic matter (?13C = - 14.7 to - 21.3‰). The soil gas CO2 ?13C values were consistent with near-water table VC groundwater ?13C values (- 36.8 to - 39.5‰), suggesting CO2 originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO2 concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour biodegradation rates were independent of substrate (VC and/or oxygen) concentration. The high correlation (R = 0.962 to 0.975) between CO2 concentrations and temperature suggested that aerobic biodegradation of VC was controlled by bacterial activity that was regulated by the temperature within the vadose zone. When assessing a contaminated site for possible vapour intrusion into buildings, accounting for environmental conditions for aerobic biodegradation of VC in the vadose zone should improve the assessment of environmental risk of VC intrusion into buildings, enabling better identification and prioritisation of contaminated sites to be remediated.

Patterson, B. M.; Aravena, R.; Davis, G. B.; Furness, A. J.; Bastow, T. P.; Bouchard, D.

2013-10-01

399

Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates.  

PubMed

A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (?¹³C -5.2 to -10.9‰) compared to groundwater (?¹³C -39.5‰) at the on-site location. Soil gas CO? isotope analysis at both locations showed that CO? was highly isotopically depleted (?¹³C -28.8 to -33.3‰), compared to soil gas CO? data originating from natural sediment organic matter (?¹³C= -14.7 to -21.3‰). The soil gas CO2 ?¹³C values were consistent with near-water table VC groundwater ?¹³C values (-36.8 to -39.5‰), suggesting CO? originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE)) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO? concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour biodegradation rates were independent of substrate (VC and/or oxygen) concentration. The high correlation (R=0.962 to 0.975) between CO? concentrations and temperature suggested that aerobic biodegradation of VC was controlled by bacterial activity that was regulated by the temperature within the vadose zone. When assessing a contaminated site for possible vapour intrusion into buildings, accounting for environmental conditions for aerobic biodegradation of VC in the vadose zone should improve the assessment of environmental risk of VC intrusion into buildings, enabling better identification and prioritisation of contaminated sites to be remediated. PMID:23999077

Patterson, B M; Aravena, R; Davis, G B; Furness, A J; Bastow, T P; Bouchard, D

2013-10-01

400

Maximal Aerobic Power versus Performance in Two Aerobic Endurance Tests among Young and Old Adults  

Microsoft Academic Search

Background: Aerobic fitness is of great value for reducing risk of mortality and cardiovascular diseases. Objective: This study evaluated the performance in and correlations between a new test (five-minute pyramid test, 5MPT), the six-minute walk-test (6MWT) and maximal oxygen uptake (VO2max) among old and young adults. Methods: Forty-four habitually active adults (females and males), 23 old (64–79 years) and 21

Eva A. Andersson; Gunilla Lundahl; Liliane Wecke; Ida Lindblom; Johnny Nilsson

2011-01-01

401

Culturable Aerobic and Facultative Anaerobic Intestinal Bacterial Flora of Black Cobra (Naja naja karachiensis) in Southern Pakistan  

PubMed Central

Using morphological analysis and biochemical testing, here for the first time, we determined the culturable gut bacterial flora (aerobes and facultative anaerobes) in the venomous Black Cobra (Naja naja karachiensis) from South Asia. The findings revealed that these snakes inhabit potentially pathogenic bacteria including Serratia marcescens, Pseudomonas aeruginosa, Shewanella putrefaciens, Aeromonas hydrophila, Salmonella sp., Moraxella sp., Bacillus sp., Ochrobactrum anthropi, and Providencia rettgeri. These findings are of concern, as injury from snake bite can result in wound infections and tissue necrosis leading to sepsis/necrotizing fasciitis and/or expose consumers of snake meat/medicine in the community to infections. PMID:25002979

Iqbal, Junaid; Sagheer, Mehwish; Tabassum, Nazneen; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

2014-01-01

402

Culturable Aerobic and Facultative Anaerobic Intestinal Bacterial Flora of Black Cobra (Naja naja karachiensis) in Southern Pakistan.  

PubMed

Using morphological analysis and biochemical testing, here for the first time, we determined the culturable gut bacterial flora (aerobes and facultative anaerobes) in the venomous Black Cobra (Naja naja karachiensis) from South Asia. The findings revealed that these snakes inhabit potentially pathogenic bacteria including Serratia marcescens, Pseudomonas aeruginosa, Shewanella putrefaciens, Aeromonas hydrophila, Salmonella sp., Moraxella sp., Bacillus sp., Ochrobactrum anthropi, and Providencia rettgeri. These findings are of concern, as injury from snake bite can result in wound infections and tissue necrosis leading to sepsis/necrotizing fasciitis and/or expose consumers of snake meat/medicine in the community to infections. PMID:25002979

Iqbal, Junaid; Sagheer, Mehwish; Tabassum, Nazneen; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

2014-01-01

403

Aerobic methanotrophy within the pelagic redox-zone of the Gotland Deep (central Baltic Sea)  

NASA Astrophysics Data System (ADS)

Water column samples taken in summer 2008 from the stratified Gotland Deep (central Baltic Sea) showed a strong gradient in dissolved methane concentrations from high values in the saline deep water (max. 504 nM) to low concentrations in the less dense, brackish surface water (about 4 nM). The steep methane-gradient (between 115 and 135 m water depth) within the redox-zone, which separates the anoxic deep part from the oxygenated surface water (oxygen concentration 0-0.8 mL L-1), implies a methane consumption rate of 0.28 nM d-1. The process of microbial methane oxidation within this zone was evident by a shift of the stable carbon isotope ratio of methane between the bottom water (?13C CH4 = -82.4‰ and the redox-zone (?13C CH4 = -38.7‰. Water column samples between 80 and 119 m were studied to identify the microorganisms responsible for the methane turnover in that depth interval. Notably, methane monooxygenase gene expression analyses for water depths covering the whole redox-zone demonstrated that accordant methanotrophic activity was probably due to only one phylotype of the aerobic type I methanotrophic bacteria. An imprint of these organisms on the particular organic matter was revealed by distinctive lipid biomarkers showing bacteriohopanepolyols and lipid fatty acids characteristic for aerobic type I methanotrophs (e.g., 35-aminobacteriohopane-30,31,32,33,34-pentol), corroborating their role in aerobic methane oxidation in the redox-zone of the central Baltic Sea.

Schmale, O.; Blumenberg, M.; Kießlich, K.; Jakobs, G.; Berndmeyer, C.; Labrenz, M.; Thiel, V.; Rehder, G.

2012-12-01

404

Upper limb aerobic training improves aerobic fitness and all-out performance of America's Cup grinders.  

PubMed

This research on "America's Cup" grinders investigated the effects of a specific eight-week long-arm cranking ergometer (ACE) training on upper body (UB) aerobic fitness (ventilatory threshold - Tvent, respiratory compensation point- RCP, -oxygen uptake peak - [Formula: see text]O2peak) and high intensity working capacity. The training consisted of sessions carried out for 20-30 mins, three times per week, at an intensity between the UB-Tvent and UB-RCP, and replaced part of a typical lower limb aerobic training whilst maintaining the usual weekly schedule of callisthenics, resistance training and sailing. Seven sailors, including four grinders and three mastmen (age 30 ± 5.5 years, height 1.9 ± 0.04 m, body mass 102 ± 3.6 kg), were evaluated through both an ACE cardiopulmonary maximal exercise test (CPET) and an ACE all-out up to exhaustion exercise test, before and after the ACE training. UB aerobic fitness improved significantly: UB-[Formula: see text]O2peak increased from 4.29 ± 0.442 to 4.52 ± 0.522 l·min(-1) (6.4 ± 3.66%), [Formula: see text]O2 at UB-Tvent from 2.42 ± 0.282 to 2.97 ± 0.328 l·min(-1) (22.8 ± 5.09%) and [Formula: see text]O2 at UB-RCP from 3.25 ± 0.402 to 3.75 ± 0.352 l·min(-1) (16.1 ± 10.83%). Peak power at the ACE CPET increased from 351 ± 27.5 to 387 ± 33.5 W (10.5 ± 6.93%). The all-out test total mechanical work increased from 28.9 ± 2.35 to 40.1 ± 3.76 kJ (72.1 ± 4.67%). In conclusion, a high intensity aerobic ACE training can be effective in improving grinding performance by increasing UB aerobic fitness and all-out working capacity. PMID:25357134

Adami, Paolo Emilio; Delussu, Anna Sofia; Rodio, Angelo; Squeo, Maria Rosaria; Corsi, Loretta; Quattrini, Filippo Maria; Fattorini, Luigi; Bernardi, Marco

2014-10-30

405

Effect of topical antimicrobial treatment on aerobic bacteria in the stratum corneum of human skin.  

PubMed

The efficacy of antimicrobial agents applied topically to the skin surface in eradicating coagulase-negative staphylococci (CNS) residing in the stratum corneum underlying the surface was examined. Glabrous skin was sampled with a 26-cm2 contact plate containing Trypticase soy agar. Five antiseptic solutions and four antimicrobial ointments were evaluated. The antiseptic solutions (10% povidone-iodine, 2% aqueous iodine, 2% tincture of iodine, 70% ethanol, and 0.5% chlorhexidine-ethanol) were applied for 15 s with a gauze sponge. The antimicrobial ointments (iodophor, silver sulfadiazine, mupirocin, and a triple-antibiotic ointment containing neomycin, polymyxin, and bacitracin) were applied and covered for 6 h with gauze. After treatment, the surface was sampled, 15 to 25 keratinized layers were subsequently removed by sequential stripping with cellophane tape, and the stratum corneum was sampled. All agents were effective in eradicating CNS from the surface (80 of 88 trials). However, only 2% iodine (17 of 20 trials), iodophor (8 of 12), mupirocin (6 of 10), and the triple-antibiotic ointment (9 of 11) eradicated CNS from the stratum corneum reliably (greater than or equal to 50% of trials). The stratum corneum was repopulated with resident flora within 24 h of treatment with 2% iodine (4 of 4 trials), iodophor (6 of 7), or mupirocin (5 of 6), but repopulation occurred in only 1 of 7 trials with the triple-antibiotic ointment. Topical treatment of skin with antimicrobial agents usually eradicates CNS from the skin surface but may not eradicate CNS from the stratum corneum. Only the triple-antibiotic ointment eradicated CNS from the stratum corneum and prevented repopulation with resident flora. PMID:2069368

Hendley, J O; Ashe, K M

1991-04-01

406

Pattern of aerobic bacteria with antimicrobial susceptibility causing community acquired urinary tract infection.  

PubMed

Since antibiotic resistance among uropathogens have gradually been rising, so it is important to have knowledge about the pattern and antimicrobial susceptibility to choose the correct treatment regimen. A cross sectional study was carried out in the Department of Microbiology, Mymensingh Medical College between July 2007 to June 2008 to determine the prevalence, relationship between pyuria and urine culture and antibiotic resistance pattern among the bacterial isolates of community acquired UTI (CUTI). A total of 100 urine samples were subjected to microscopy and culture. Antimicrobial susceptibility of isolates was done by disk diffusion method according to Clinical and Laboratory Standard Institute (CLSI) 2007. Of the total samples, 45(45%) were culture positive and among them female were more (71.1%) than the male (28.9%). The predominant age group was 15-29. Having pus cell >5/HPF, 93.3% culture positive patients showed significant pyuria. The isolated microorganisms were Escherichia coli (73%) followed by Staphylococcus saprophyticus (11.1%), Klebsiella spp (6.7%), Enterobacter spp (4.4%), Pseudomonas aeruginosa (2.2%) and Proteus spp (2.2%). All the bacterial isolates were sensitive to imipenem, while they showed variation in sensitivity to other commonly used antibiotics. Imipenem, nitrofurantoin and gentamicin were found to be effective for Gram-negative isolates and imipenem, azithromycin, vancomycin, ceftazidime for Gram-positive isolates. Our study emphasized over the changing etiology and emergence of drug resistance of the UTI within our country. PMID:19623138

Parvin, U S; Hossain, M A; Musa, A K; Mahamud, C; Islam, M T; Haque, N; Muhammad, N; Khan, S I; Mahmud, N U

2009-07-01

407

Aerobic spore-forming bacteria and chemical composition of some Nigerian fermented soup condiments.  

PubMed

A total of 97 strains of spore-forming Bacillus were isolated from 45 samples of three Nigerian fermented condiments, obtained from retail markets located in Southwestern Nigeria. The isolates were identified as B. subtilis (33%), B. pumilus (19%), B. licheniformis (22%), B. brevis (9%), B. megaterium (12%) and B. polymyxa (5%). The microbial load of the condiments showed that the average count of spore-formers was between 107 to 109 cfu/g. The moisture contents of iru, ugba and ogiri were 57.18%, 46.32% and 42.34%, respectively, while the protein contents were 18.26%, 17.17% and 17.96%. The percentage fat was 29.88%, 40.25% and 44.14% for iru, ugba and ogiri. The ash content ranged from 5.8 to 6.1%; a 0.1% titratable acidity and pH values above 7.0 were obtained for the three condiments. PMID:10898480

Sanni, A I; Ayerno, G S; Sakyi-Dawson, E; Sefa-Dedeh, S

2000-01-01

408

Aerobic and anaerobic bacteria in subgingival and supragingival plaques of adult patients with periodontal disease  

Microsoft Academic Search

Purpose: Clinical, epidemiological and microbiological examinations of adult patients with periodontal disease. Material and methods: The study of population consisted of 21 subjects (13 female and 8 male) aged 38-58 years, treated in the Outpatient Department of Periodontology. Dental examinations were performed at an artificial light and using a WHO periodontometer, a mirror and a probe. Periodontal status was assessed

Daniluk T; Tokajuk G; Cylwik-Rokicka D; Stokowska W

2006-01-01

409

Aerobic bacteria in the oral cavity of patients with removable dentures  

Microsoft Academic Search

Purpose: Determination of bacterial composition in the oral cavity of patients with removable dentures and with own dentition (without dentures). Material and methods: Bacteriological investigations were performed in 55 patients from the department of inter- nal medicine (32 diabetic patients) and 40 patients treated in surgical department (25 patients with malignancy). Pal- ate mucosa and tongue dorsa swabs were collected

Daniluk T; Fiedoruk K; Cylwik-Rokicka D; Tokajuk G; Stokowska W

2006-01-01

410

Bacteria turn tiny gears  

SciTech Connect

Swarms of bacteria turn two 380-micron long gears, opening the possibility of building hybrid biological machines at the microscopic scale. Read more at Wired: http://www.wired.com/wiredscience/2009/12/bacterial-micro-machine/#more-15684 or Scientific American: http://www.scientificamerican.com/article.cfm?id=brownian-motion-bacteria

None

2009-01-01

411

Laboratory evaluation of bioaugmentation for aerobic treatment of RDX in groundwater.  

PubMed

The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km(+). All three strains were transported through the columns and eluted ahead of the conservative bromide tracer, although the total breakthrough varied by strain. The introduced cells responded to biostimulation with fructose (18 mg L(-1), 0.1 mM) by degrading dissolved RDX (0.5 mg L(-1), 2.3 µM). The strains retained RDX-degrading activity for at least 6 months following periods of starvation when no fructose was supplied to the column. Post-experiment analysis of the soil indicated that the residual cells were distributed along the length of the column. When the strains were grown to densities relevant for field-scale application, the cells remained viable and able to degrade RDX for at least 3 months when stored at 4 °