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Sample records for coli tryptophanase cold

  1. Structure of Escherichia coli tryptophanase.

    PubMed

    Ku, Shao Yang; Yip, Patrick; Howell, P Lynne

    2006-07-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the alpha-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the alpha-proton of the substrate for beta-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal. PMID:16790938

  2. Structure of Escherichia Coli Tryptophanase

    SciTech Connect

    Ku,S.; Yip, P.; Howell, P.

    2006-01-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the {alpha}-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the {alpha}-proton of the substrate for {beta}-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal.

  3. A structural view of the dissociation of Escherichia coli tryptophanase.

    PubMed

    Green, Keren; Qasim, Nasrin; Gdaelvsky, Garik; Kogan, Anna; Goldgur, Yehuda; Parola, Abraham H; Lotan, Ofra; Almog, Orna

    2015-12-01

    Tryptophanase (Trpase) is a pyridoxal 5'-phosphate (PLP)-dependent homotetrameric enzyme which catalyzes the degradation of L-tryptophan. Trpase is also known for its cold lability, which is a reversible loss of activity at low temperature (2°C) that is associated with the dissociation of the tetramer. Escherichia coli Trpase dissociates into dimers, while Proteus vulgaris Trpase dissociates into monomers. As such, this enzyme is an appropriate model to study the protein-protein interactions and quaternary structure of proteins. The aim of the present study was to understand the differences in the mode of dissociation between the E. coli and P. vulgaris Trpases. In particular, the effect of mutations along the molecular axes of homotetrameric Trpase on its dissociation was studied. To answer this question, two groups of mutants of the E. coli enzyme were created to resemble the amino-acid sequence of P. vulgaris Trpase. In one group, residues 15 and 59 that are located along the molecular axis R (also termed the noncatalytic axis) were mutated. The second group included a mutation at position 298, located along the molecular axis Q (also termed the catalytic axis). Replacing amino-acid residues along the R axis resulted in dissociation of the tetramers into monomers, similar to the P. vulgaris Trpase, while replacing amino-acid residues along the Q axis resulted in dissociation into dimers only. The crystal structure of the V59M mutant of E. coli Trpase was also determined in its apo form and was found to be similar to that of the wild type. This study suggests that in E. coli Trpase hydrophobic interactions along the R axis hold the two monomers together more strongly, preventing the dissociation of the dimers into monomers. Mutation of position 298 along the Q axis to a charged residue resulted in tetramers that are less susceptible to dissociation. Thus, the results indicate that dissociation of E. coli Trpase into dimers occurs along the molecular Q axis. PMID

  4. Inhibition of the Induced Formation of Tryptophanase in Escherichia coli by Near-Ultraviolet Radiation

    PubMed Central

    Swenson, P. A.; Setlow, R. B.

    1970-01-01

    Induced formation of tryptophanase in Escherichia coli B/r is temporarily inhibited by near-ultraviolet (UV) irradiation. The inhibition is greater when irradiation is at 5 C than when at room temperature. Hence, the inhibition is the result of a photochemical, rather than photoenzymatic, alteration of some cellular component. The action spectrum has a peak in the region of 334 nm and is similar to that for growth delay. However, inhibition of tryptophanase formation is more sensitive to near-UV irradiation than are growth, respiration, and the induced formation of β-galactosidase. Thus, for tryptophanase the lack of formation cannot be due to general inhibition of metabolism. Pyridoxal phosphate absorbs in the near-UV region of the spectrum and is a cofactor for tryptophanase, but this enzyme in induced cells is not inactivated by near UV-radiations. An experiment in which toluene-treated suspensions from irradiated and unirradiated cells were mixed showed that irradiation does not cause the formation of an inhibitor of tryptophanase activity. The possibility remains that the absorption of radiant energy by pyridoxal phosphate interferes with the synthesis of tryptophanase. PMID:4914082

  5. CsrA and TnaB coregulate tryptophanase activity to promote exotoxin-induced killing of Caenorhabditis elegans by enteropathogenic Escherichia coli.

    PubMed

    Bhatt, Shantanu; Anyanful, Akwasi; Kalman, Daniel

    2011-09-01

    Enteropathogenic Escherichia coli(EPEC) requires the tnaA-encoded enzyme tryptophanase and its substrate tryptophan to synthesize diffusible exotoxins that kill the nematode Caenorhabditis elegans. Here, we demonstrate that the RNA-binding protein CsrA and the tryptophan permease TnaB coregulate tryptophanase activity, through mutually exclusive pathways, to stimulate toxin-mediated paralysis and killing of C. elegans. PMID:21705596

  6. Cloning, nucleotide sequences, and overexpression in Escherichia coli of tandem copies of a tryptophanase gene in an obligately symbiotic thermophile, Symbiobacterium thermophilum.

    PubMed Central

    Hirahara, T; Suzuki, S; Horinouchi, S; Beppu, T

    1992-01-01

    Symbiobacterium thermophilum, a thermophilic bacterium, is a thermostable tryptophanase producer that can grow only in coculture with a specific Bacillus strain. Two thermostable tryptophanase genes, tna-1 and tna-2, that are located close to each other were cloned into Escherichia coli from S. thermophilum by the DNA-probing method. The nucleotide and deduced amino acid sequences indicate that Tna1 and Tna2 share 92% identical amino acids in a total of 453 amino acids. By means of DNA manipulation with E. coli host-vector systems, Tna1 and Tna2 were produced in very large amounts in enzymatically active forms. Comparison of the NH2-terminal amino acid sequences and the enzymatic properties of the tryptophanases purified from the original S. thermophilum strain and these two tryptophanases from recombinant E. coli cells suggest that in S. thermophilum, only Tna2 is produced and tna-1 is silent. Notwithstanding the great similarity in amino acid sequence between Tna1 and Tna2, the two enzymes differ markedly in activation energy for catalysis and thermostability. Images PMID:1339259

  7. Characterization of tryptophanase from Vibrio cholerae.

    PubMed

    Nuidate, Taiyeebah; Tansila, Natta; Chomchuen, Piraporn; Phattaranit, Phattiphong; Eangchuan, Supachok; Vuddhakul, Varaporn

    2015-01-01

    Tryptophanase (Trpase) is a pyridoxal phosphate (PLP)-dependent enzyme responsible for the production of indole, an important intra- and interspecies signaling molecule in bacteria. In this study, the tnaA gene of Vibrio cholerae coding for VcTrpase was cloned into the pET-20b(+) vector and expressed in Escherichia coli BL21(DE3) tn5:tnaA. Using Ni(2+)-nitrilotriacetic acid (NTA) chromatography, VcTrpase was purified, and it possessed a molecular mass of ∼49 kDa with specific absorption peaks at 330 and 435 nm and a specific activity of 3 U/mg protein. The VcTrpase had an 80 % homology to the Trpase of Haemophilus influenzae and E. coli, but only around 50 % identity to the Trpase of Proteus vulgaris and Porphyromonas gingivalis. The optimum conditions for the enzyme were at pH 9.0 and 45 °C. Recombinant VcTrpase exhibited analogous kinetic reactivity to the EcTrpase with K m and k cat values of 0.612 × 10(-3) M and 5.252 s(-1), respectively. The enzyme catalyzed S-methyl-L-cysteine and S-benzyl-L-cysteine degradation, but not L-phenylalanine and L-serine. Using a site-directed mutagenesis technique, eight residues (Thr52, Tyr74, Arg103, Asp137, Arg230, Lys269, Lys270, and His463) were conserved for maintaining enzyme catalysis. All amino acid substitutions at these sites either eliminated or remarkably diminished Trpase activity. These sites are thus potential targets for the design of drugs to control the V. cholerae Trpase and to further investigate its functions. PMID:25253268

  8. The tryptophanase gene cluster of Haemophilus influenzae type b: evidence for horizontal gene transfer.

    PubMed

    Martin, K; Morlin, G; Smith, A; Nordyke, A; Eisenstark, A; Golomb, M

    1998-01-01

    Among strains of Haemophilus influenzae, the ability to catabolize tryptophan (as detected by indole production) varies and is correlated with pathogenicity. Tryptophan catabolism is widespread (70 to 75%) among harmless respiratory isolates but is nearly universal (94 to 100%) among strains causing serious disease, including meningitis. As a first step in investigating the relationship between tryptophan catabolism and virulence, we have identified genes in pathogenic H. influenzae which are homologous to the tryptophanase (tna) operon of Escherichia coli. The tna genes are located on a 3.1-kb fragment between nlpD and mutS in the H. influenzae type b (Eagan) genome, are flanked by 43-bp direct repeats of an uptake signal sequence downstream from nlpD, and appear to have been inserted as a mobile unit within this sequence. The organization of this insertion is reminiscent of pathogenicity islands. The tna cluster is found at the same map location in all indole-positive strains of H. influenzae surveyed and is absent from reference type d and e genomes. In contrast to H. influenzae, most other Haemophilus species lack tna genes. Phylogenetic comparisons suggest that the tna cluster was acquired by intergeneric lateral transfer, either by H. influenzae or a recent ancestor, and that E. coli may have acquired its tnaA gene from a related source. Genomes of virulent H. influenzae resemble those of pathogenic enterics in having an island of laterally transferred DNA next to mutS. PMID:9422600

  9. Cold Plasma Inactivates Salmonella and Escherichia coli O157:H7 on Fresh Produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This presentation will summarize recent advances in cold plasma technology at the USDA’s Eastern Regional Research Center. Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the surfaces of golden delicious apples. ...

  10. Crystal structure of CspA, the major cold shock protein of Escherichia coli.

    PubMed

    Schindelin, H; Jiang, W; Inouye, M; Heinemann, U

    1994-05-24

    The major cold shock protein of Escherichia coli, CspA, produced upon a rapid downshift in growth temperature, is involved in the transcriptional regulation of at least two genes. The protein shares high homology with the nucleic acid-binding domain of the Y-box factors, a family of eukaryotic proteins involved in transcriptional and translational regulation. The crystal structure of CspA has been determined at 2-A resolution and refined to R = 0.187. CspA is composed of five antiparallel beta-strands forming a closed five-stranded beta-barrel. The three-dimensional structure of CspA is similar to that of the major cold shock protein of Bacillus subtilis, CspB, which has recently been determined at 2.45-A resolution. However, in contrast to CspB, no dimer is formed in the crystal. The surface of CspA is characteristic for a protein interacting with single-stranded nucleic acids. Due to the high homology of the bacterial cold shock proteins with the Y-box factors, E. coli CspA and B. subtilis CspB define a structural framework for the common cold shock domain. PMID:8197194

  11. Biologically Synthesized Gold Nanoparticles Ameliorate Cold and Heat Stress-Induced Oxidative Stress in Escherichia coli.

    PubMed

    Zhang, Xi-Feng; Shen, Wei; Gurunathan, Sangiliyandi

    2016-01-01

    Due to their unique physical, chemical, and optical properties, gold nanoparticles (AuNPs) have recently attracted much interest in the field of nanomedicine, especially in the areas of cancer diagnosis and photothermal therapy. Because of the enormous potential of these nanoparticles, various physical, chemical, and biological methods have been adopted for their synthesis. Synthetic antioxidants are dangerous to human health. Thus, the search for effective, nontoxic natural compounds with effective antioxidative properties is essential. Although AuNPs have been studied for use in various biological applications, exploration of AuNPs as antioxidants capable of inhibiting oxidative stress induced by heat and cold stress is still warranted. Therefore, one goal of our study was to produce biocompatible AuNPs using biological methods that are simple, nontoxic, biocompatible, and environmentally friendly. Next, we aimed to assess the antioxidative effect of AuNPs against oxidative stress induced by cold and heat in Escherichia coli, which is a suitable model for stress responses involving AuNPs. The response of aerobically grown E. coli cells to cold and heat stress was found to be similar to the oxidative stress response. Upon exposure to cold and heat stress, the viability and metabolic activity of E. coli was significantly reduced compared to the control. In addition, levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and leakage of proteins and sugars were significantly elevated, and the levels of lactate dehydrogenase activity (LDH) and adenosine triphosphate (ATP) significantly lowered compared to in the control. Concomitantly, AuNPs ameliorated cold and heat-induced oxidative stress responses by increasing the expression of antioxidants, including glutathione (GSH), glutathione S-transferase (GST), super oxide dismutase (SOD), and catalase (CAT). These consistent physiology and biochemical data suggest that AuNPs can ameliorate cold and heat stress

  12. Cold plasma reduction of Salmonella and Escherichia coli 0157:H7 on almonds using ambient pressure gases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of raw nuts, including almonds, is a food safety concern. Cold plasma is a novel antimicrobial intervention that can eliminate foodborne pathogens. The objective of this work was to evaluate the efficacy of rapid cold plasma treatments in eliminating Salmonella and Escherichia coli O15...

  13. Assignment of ozone-sensitive tryptophan residue in tryptophanase by a dual-monitoring high-performance liquid chromatography system

    SciTech Connect

    Ida, N.; Tokushige, M.

    1985-02-01

    Tryptophanase purified from Escherichia coli B/1t7-A is inactivated by mild ozonization following pseudo-first-order kinetics. Previous data from the authors suggest that one out of two tryptophan residues (Trp's) in the enzyme subunit is preferentially oxidized concomitant with the ozone inactivation and has a direct interaction with the coenzyme, pyridoxal phosphate. To determine which Trp is more susceptible to ozonization and interacts with PLP, the native and ozonized enzyme proteins were cleaved by trypsin and the two Trp-containing peptides were analyzed by reverse-phase HPLC equipped with a dual-monitoring system consisting of an uv and a fluorescence monitor connected in tandem for selective detection of Trp-containing peptides. This device facilitated rapid detection and quantitation of the Trp-containing peptides which decreased upon ozonization. The results showed that Trp preferentially oxidized upon ozonization and involved in the interaction with PLP was the one in peptide T-15 rather than that in T-23, which Kagamiyama et al. originally designated.

  14. Analysis of the tryptophanase expression in Symbiobacterium thermophilum in a coculture with Geobacillus stearothermophilus.

    PubMed

    Watsuji, Tomo-O; Takano, Hideaki; Yamabe, Tomoya; Tamazawa, Satoshi; Ikemura, Hiroka; Ohishi, Takanori; Matsuda, Tohyo; Shiratori-Takano, Hatsumi; Beppu, Teruhiko; Ueda, Kenji

    2014-12-01

    The tryptophanase-positive Symbiobacterium thermophilum is a free-living syntrophic bacterium that grows effectively in a coculture with Geobacillus stearothermophilus. Our studies have shown that S. thermophilum growth depends on the high CO2 and low O2 condition established by the precedent growth of G. stearothermophilus. The use of an anoxic atmosphere containing high CO2 allows S. thermophilum to grow independently of G. stearothermophilus, but the cellular yield is ten times lower than that achieved in the coculture. In this study, we characterized the coculture-dependent expression and activity of tryptophanase in S. thermophilum. S. thermophilum cells accumulated a marked amount of indole in a coculture with G. stearothermophilus, but not in the bacterium's pure culture irrespective of the addition of tryptophan. S. thermophilum cells accumulated indole in its pure culture consisting of conditioned medium (medium supplied with culture supernatant of G. stearothermophilus). Proteomic analysis identified the protein specifically produced in the S. thermophilum cells grown in conditioned medium, which was a tryptophanase encoded by tna2 (STH439). An attempt to isolate the tryptophanase-inducing component from the culture supernatant of G. stearothermophilus was unsuccessful, but we did discover that the indole accumulation occurs when 10 mM bicarbonate is added to the medium. RT-PCR analysis showed that the addition of bicarbonate stimulated transcription of tna2. The transcriptional start site, identified within the tna2 promoter, was preceded by the -24 and -12 consensus sequences specified by an alternative sigma factor, σ(54). The evidence suggests that the transcription of some genes involved in amino acid metabolism is σ(54)-dependent, and that a bacterial enhancer-binding protein containing a PAS domain controls the transcription under the presence of high levels of bicarbonate. PMID:25200839

  15. Flexible enantioselectivity of tryptophanase attributable to benzene ring in heterocyclic moiety of d-tryptophan.

    PubMed

    Shimada, Akihiko; Ozaki, Haruka

    2012-01-01

    The invariance principle of enzyme enantioselectivity must be absolute because it is absolutely essential to the homochiral biological world. Most enzymes are strictly enantioselective, and tryptophanase is one of the enzymes with extreme absolute enantioselectivity for L-tryptophan. Contrary to conventional knowledge about the principle, tryptophanase becomes flexible to catalyze D-tryptophan in the presence of diammonium hydrogenphosphate. Since D-amino acids are ordinarily inert or function as inhibitors even though they are bound to the active site, the inhibition behavior of D-tryptophan and several inhibitors involved in this process was examined in terms of kinetics to explain the reason for this flexible enantioselectivity in the presence of diammonium hydrogenphosphate. Diammonium hydrogenphosphate gave tryptophanase a small conformational change so that D-tryptophan could work as a substrate. As opposed to other D-amino acids, D-tryptophan is a very bulky amino acid with a benzene ring in its heterocyclic moiety, and so we suggest that this structural feature makes the catalysis of D-tryptophan degradation possible, consequently leading to the flexible enantioselectivity. The present results not only help to understand the mechanism of enzyme enantioselectivity, but also shed light on the origin of homochirality. PMID:25382167

  16. Inactivation of Escherichia coli ATCC 11775 in fresh produce using atmospheric pressure cold plasma

    NASA Astrophysics Data System (ADS)

    Bermudez-Aguirre, Daniela; Wemlinger, Erik; Barbosa-Canovas, Gustavo; Pedrow, Patrick; Garcia-Perez, Manuel

    2011-10-01

    Food-borne outbreaks are associated with the presence of pathogenic bacteria in food products such as fresh produce. One of the target microorganisms is Escherichia coli which exhibits resistance to being inactivated with conventional disinfection methods for vegetables. Atmospheric pressure cold plasma (APCP) was tested to disinfect three vegetables with challenge surfaces, lettuce, carrots and tomatoes. The produce was inoculated with the bacteria to reach an initial microbial concentration of 107 cfu/g. Vegetables were initially exposed to the APCP discharges from a needle array at 5.7 kV RMS in argon, processing times of 0.5, 3 and 5 min. Initial results indicate that microbial decontamination is effective on the lettuce (1.2 log reduction) when compared with other vegetables. To claim disinfection, a 3 log reduction or more is needed, which makes APCP treatment very promising technology for decontamination of produce. We propose that with method refinements full disinfection can be achieved using APCP.

  17. Optimization of cold-adapted alpha-galactosidase expression in Escherichia coli.

    PubMed

    Golotin, V A; Balabanova, L A; Noskova, Yu A; Slepchenko, L V; Bakunina, I Yu; Vorobieva, N S; Terenteva, N A; Rasskazov, V A

    2016-07-01

    α-Galactosidase (α-PsGal) of the cold-adapted marine bacterium Pseudoalteromonas sp. KMM 701 was cloned into the pET-40b(+) vector to study its properties and to develop an effective method for modifying human B-erythrocytes into O-blood group. The use of heat-shock as a pre-induction treatment, IPTG concentration of 0.2 mM and post-induction cultivation at 18 °C for 20 h in the developed MX-medium allowed increasing the recombinant Escherichia coli Rosetta (DE3)/40Gal strain productivity up to 30 times and the total soluble α-PsGal yield up to 40 times. PMID:27033343

  18. Tryptophanase-catalyzed L-tryptophan synthesis from D-serine in the presence of diammonium hydrogen phosphate.

    PubMed

    Shimada, Akihiko; Ozaki, Haruka; Saito, Takeshi; Noriko, Fujii

    2009-06-01

    Tryptophanase, an enzyme with extreme absolute stereospecificity for optically active stereoisomers, catalyzes the synthesis of l-tryptophan from l-serine and indole through a beta-substitution mechanism of the ping-pong type, and has no activity on d-serine. We previously reported that tryptophanase changed its stereospecificity to degrade d-tryptophan in highly concentrated diammonium hydrogen phosphate, (NH(4))(2)HPO(4) solution. The present study provided the same stereospecific change seen in the d-tryptophan degradation reaction also occurs in tryptophan synthesis from d-serine. Tryptophanase became active to d-serine to synthesize l-tryptophan in the presence of diammonium hydrogen phosphate. This reaction has never been reported before. d-serine seems to undergo beta-replacement via an enzyme-bonded alpha-aminoacylate intermediate to yield l-tryptophan. PMID:19582219

  19. Cold Plasma Inactivates Salmonella Stanley and Escherichia coli O157:H7 Inoculated on Golden Delicious Apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley on agar plates and inoculated onto the surfaces of golden delicious apples. This novel sanitizing technology inactivated both pathogens on agar plates, with higher flow rate (40 ...

  20. Heterologous expression of antifreeze protein gene AnAFP from Ammopiptanthus nanus enhances cold tolerance in Escherichia coli and tobacco.

    PubMed

    Deng, Long-Qun; Yu, Hao-Qiang; Liu, Yan-Ping; Jiao, Pei-Pei; Zhou, Shu-Feng; Zhang, Su-Zhi; Li, Wan-Chen; Fu, Feng-Ling

    2014-04-10

    Antifreeze proteins are a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival under the subzero environments. Ammopiptanthus nanus is the unique evergreen broadleaf bush endemic to the Mid-Asia deserts. It survives at the west edge of the Tarim Basin from the disappearance of the ancient Mediterranean in the Tertiary Period. Its distribution region is characterized by the arid climate and extreme temperatures, where the extreme temperatures range from -30 °C to 40 °C. In the present study, the antifreeze protein gene AnAFP of A. nanus was used to transform Escherichia coli and tobacco, after bioinformatics analysis for its possible function. The transformed E. coli strain expressed the heterologous AnAFP gene under the induction of isopropyl β-D-thiogalactopyranoside, and demonstrated significant enhancement of cold tolerance. The transformed tobacco lines expressed the heterologous AnAFP gene in response to cold stress, and showed a less change of relative electrical conductivity under cold stress, and a less wilting phenotype after 16 h of -3 °C cold stress and thawing for 1h than the untransformed wild-type plants. All these results imply the potential value of the AnAFP gene to be used in genetic modification of commercially important crops for improvement of cold tolerance. PMID:24502990

  1. De novo Synthesis and Assembly of rRNA into Ribosomal Subunits during Cold Acclimation in Escherichia coli.

    PubMed

    Piersimoni, Lolita; Giangrossi, Mara; Marchi, Paolo; Brandi, Anna; Gualerzi, Claudio O; Pon, Cynthia L

    2016-04-24

    During the cold adaptation that follows a cold stress, bacterial cells undergo many physiological changes and extensive reprogramming of their gene expression pattern. Bulk gene expression is drastically reduced, while a set of cold shock genes is selectively and transiently expressed. The initial stage of cold acclimation is characterized by the establishment of a stoichiometric imbalance of the translation initiation factors (IFs)/ribosomes ratio that contributes to the preferential translation of cold shock transcripts. Whereas de novo synthesis of the IFs following cold stress has been documented, nothing was known concerning the activity of the rrn operons during the cold acclimation period. In this work, we focus on the expression of the rrn operons and the fate of rRNA after temperature downshift. We demonstrate that in Escherichia coli, rRNA synthesis does not stop during the cold acclimation phase, but continues with greater contribution of the P2 compared to the P1 promoter and all seven rrn operons are active, although their expression levels change with respect to pre-stress conditions. Eight hours after the 37°→10°C temperature downshift, the newly transcribed rRNA represents up to 20% of total rRNA and is preferentially found in the polysomes. However, with respect to the de novo synthesis of the IFs, both rRNA transcription and maturation are slowed down drastically by cold stress, thereby accounting in part for the stoichiometric imbalance of the IFs/ribosomes. Overall, our data indicate that new ribosomes, which are possibly suitable to function at low temperature, are slowly assembled during cold acclimation. PMID:26953262

  2. Development of a Cold-Adapted Pseudoalteromonas Expression System for the Pseudoalteromonas Proteins Intractable for the Escherichia coli System.

    PubMed

    Yu, Zi-Chao; Tang, Bai-Lu; Zhao, Dian-Li; Pang, Xiuhua; Qin, Qi-Long; Zhou, Bai-Cheng; Zhang, Xi-Ying; Chen, Xiu-Lan; Zhang, Yu-Zhong

    2015-01-01

    Although the Escherichia coli expression system is the most commonly used expression system, some proteins are still difficult to be expressed by this system, such as proteins with high thermolability and enzymes that cannot mature by autoprocessing. Therefore, it is necessary to develop alternative expression systems. In this study, a cold-adapted Pseudoalteromonas expression system was developed. A shuttle vector was constructed, and a conjugational transfer system between E. coli and psychrophilic strain Pseudoalteromonas sp. SM20429 was established. Based on the shuttle vector, three reporter vectors were constructed to compare the strength of the cloned promoters at low temperature. The promoter of xylanase gene from Pseudoalteromonas sp. BSi20429 was chosen due to its high activity at 10-15°C. An expression vector pEV containing the chosen promoter, multiple cloning sites and a His tag was constructed for protein expression and purification. With pEV as expression vector and SM20429 as the host, a cold-adapted protease, pseudoalterin, which cannot be maturely expressed in E. coli, was successfully expressed as an active extracellular enzyme when induced by 2% oat spelt xylan at 15°C for 48 h. Recombinant pseudoalterin purified from the culture by Ni affinity chromatography had identical N-terminal sequence, similar molecular mass and substrate specificity as the native pseudoalterin. In addition, another two cold-adapted enzymes were also successfully expressed by this system. Our results indicate that this cold-adapted Pseudoalteromonas expression system will provide an alternative choice for protein expression, especially for the Pseudoalteromonas proteins intractable for the E. coli system. PMID:26333173

  3. Role of the ribosome-associated protein PY in the cold-shock response of Escherichia coli

    PubMed Central

    Di Pietro, Fabio; Brandi, Anna; Dzeladini, Nadire; Fabbretti, Attilio; Carzaniga, Thomas; Piersimoni, Lolita; Pon, Cynthia L; Giuliodori, Anna Maria

    2013-01-01

    Protein Y (PY) is an Escherichia coli cold-shock protein which has been proposed to be responsible for the repression of bulk protein synthesis during cold adaptation. Here, we present in vivo and in vitro data which clarify the role of PY and its mechanism of action. Deletion of yfiA, the gene encoding protein PY, demonstrates that this protein is dispensable for cold adaptation and is not responsible for the shutdown of bulk protein synthesis at the onset of the stress, although it is able to partially inhibit translation. In vitro assays reveal that the extent of PY inhibition changes with different mRNAs and that this inhibition is related to the capacity of PY of binding 30S subunits with a fairly strong association constant, thus stimulating the formation of 70S monomers. Furthermore, our data provide evidence that PY competes with the other ribosomal ligands for the binding to the 30S subunits. Overall these results suggest an alternative model to explain PY function during cold shock and to reconcile the inhibition caused by PY with the active translation observed for some mRNAs during cold shock. PMID:23420694

  4. Inactivation of Shiga toxin-producing Escherichia coli O104:H4 using cold atmospheric pressure plasma.

    PubMed

    Baier, Matthias; Janssen, Traute; Wieler, Lothar H; Ehlbeck, Jörg; Knorr, Dietrich; Schlüter, Oliver

    2015-09-01

    From cultivation to the end of the post-harvest chain, heat-sensitive fresh produce is exposed to a variety of sources of pathogenic microorganisms. If contaminated, effective gentle means of sanitation are necessary to reduce bacterial pathogen load below their infective dose. The occurrence of rare or new serotypes raises the question of their tenacity to inactivation processes. In this study the antibacterial efficiency of cold plasma by an atmospheric pressure plasma-jet was examined against the Shiga toxin-producing outbreak strain Escherichia coli O104:H4. Argon was transformed into non-thermal plasma at a power input of 8 W and a gas flow of 5 L min(-1). Basic tests were performed on polysaccharide gel discs, including the more common E. coli O157:H7 and non-pathogenic E. coli DSM 1116. At 5 mm treatment distance and 10(5) cfu cm(-2) initial bacterial count, plasma reduced E. coli O104:H4 after 60 s by 4.6 ± 0.6 log, E. coli O157:H7 after 45 s by 4.5 ± 0.6 log, and E. coli DSM 1116 after 30 s by 4.4 ± 1.1 log. On the surface of corn salad leaves, gentle plasma application at 17 mm reduced 10(4) cfu cm(-2) of E. coli O104:H4 by 3.3 ± 1.1 log after 2 min, whereas E. coli O157:H7 was inactivated by 3.2 ± 1.1 log after 60 s. In conclusion, plasma treatment has the potential to reduce pathogens such as E. coli O104:H4 on the surface of fresh produce. However, a serotype-specific adaptation of the process parameters is required. PMID:25782617

  5. Massive presence of the Escherichia coli 'major cold-shock protein' CspA under non-stress conditions.

    PubMed

    Brandi, A; Spurio, R; Gualerzi, C O; Pon, C L

    1999-03-15

    The most characteristic event of cold-shock activation in Escherichia coli is believed to be the de novo synthesis of CspA. We demonstrate, however, that the cellular concentration of this protein is > or = 50 microM during early exponential growth at 37 degrees C; therefore, its designation as a major cold-shock protein is a misnomer. The cspA mRNA level decreases rapidly with increasing cell density, becoming virtually undetectable by mid-to-late exponential growth phase while the CspA level declines, although always remaining clearly detectable. A burst of cspA expression followed by a renewed decline ensues upon dilution of stationary phase cultures with fresh medium. The extent of cold-shock induction of cspA varies as a function of the growth phase, being inversely proportional to the pre-existing level of CspA which suggests feedback autorepression by this protein. Both transcriptional and post-transcriptional controls regulate cspA expression under non-stress conditions; transcription of cspA mRNA is under the antagonistic control of DNA-binding proteins Fis and H-NS both in vivo and in vitro, while its decreased half-life with increasing cell density contributes to its rapid disappearance. The cspA mRNA instability is due to its 5' untranslated leader and is counteracted in vivo by the cold-shock DeaD box RNA helicase (CsdA). PMID:10075935

  6. Escherichia coli out in the cold: Dissemination of human-derived bacteria into the Antarctic microbiome.

    PubMed

    Power, Michelle L; Samuel, Angelingifta; Smith, James J; Stark, Jonathon S; Gillings, Michael R; Gordon, David M

    2016-08-01

    Discharge of untreated sewage into Antarctic environments presents a risk of introducing non-native microorganisms, but until now, adverse consequences have not been conclusively identified. Here we show that sewage disposal introduces human derived Escherichia coli carrying mobile genetic elements and virulence traits with the potential to affect the diversity and evolution of native Antarctic microbial communities. We compared E. coli recovered from environmental and animal sources in Antarctica to a reference collection of E. coli from humans and non-Antarctic animals. The distribution of phylogenetic groups and frequency of 11 virulence factors amongst the Antarctic isolates were characteristic of E. coli strains more commonly associated with humans. The rapidly emerging E. coli ST131 and ST95 clones were found amongst the Antarctic isolates, and ST95 was the predominant E. coli recovered from Weddell seals. Class 1 integrons were found in 15% of the Antarctic E. coli with 4 of 5 identified gene cassette arrays containing antibiotic resistance genes matching those common in clinical contexts. Disposing untreated sewage into the Antarctic environment does disseminate non-native microorganisms, but the extent of this impact and implications for Antarctic ecosystem health are, as yet, poorly understood. PMID:27179324

  7. Cold Stress Makes Escherichia coli Susceptible to Glycopeptide Antibiotics by Altering Outer Membrane Integrity.

    PubMed

    Stokes, Jonathan M; French, Shawn; Ovchinnikova, Olga G; Bouwman, Catrien; Whitfield, Chris; Brown, Eric D

    2016-02-18

    A poor understanding of the mechanisms by which antibiotics traverse the outer membrane remains a considerable obstacle to the development of novel Gram-negative antibiotics. Herein, we demonstrate that the Gram-negative bacterium Escherichia coli becomes susceptible to the narrow-spectrum antibiotic vancomycin during growth at low temperatures. Heterologous expression of an Enterococcus vanHBX vancomycin resistance cluster in E. coli confirmed that the mechanism of action was through inhibition of peptidoglycan biosynthesis. To understand the nature of vancomycin permeability, we screened for strains of E. coli that displayed resistance to vancomycin at low temperature. Surprisingly, we observed that mutations in outer membrane biosynthesis suppressed vancomycin activity. Subsequent chemical analysis of lipopolysaccharide from vancomycin-sensitive and -resistant strains confirmed that suppression was correlated with truncations in the core oligosaccharide of lipopolysaccharide. These unexpected observations challenge the current understanding of outer membrane permeability, and provide new chemical insights into the susceptibility of E. coli to glycopeptide antibiotics. PMID:26853624

  8. Atmospheric cold plasma inactivation of Escherichia coli, Salmonella enterica serovar Typhimurium and Listeria monocytogenes inoculated on fresh produce.

    PubMed

    Ziuzina, D; Patil, S; Cullen, P J; Keener, K M; Bourke, P

    2014-09-01

    Atmospheric cold plasma (ACP) represents a potential alternative to traditional methods for non-thermal decontamination of foods. In this study, the antimicrobial efficacy of a novel dielectric barrier discharge ACP device against Escherichia coli, Salmonella enterica Typhimurium and Listeria monocytogenes inoculated on cherry tomatoes and strawberries, was examined. Bacteria were spot inoculated on the produce surface, air dried and sealed inside a rigid polypropylene container. Samples were indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (70 kVRMS) air ACP and subsequently stored at room temperature for 24 h. ACP treatment for 10, 60 and 120 s resulted in reduction of Salmonella, E. coli and L. monocytogenes populations on tomato to undetectable levels from initial populations of 3.1, 6.3, and 6.7 log10 CFU/sample, respectively. However, an extended ACP treatment time was necessary to reduce bacterial populations attached on the more complex surface of strawberries. Treatment time for 300 s resulted in reduction of E. coli, Salmonella and L. monocytogenes populations by 3.5, 3.8 and 4.2 log10 CFU/sample, respectively, and also effectively reduced the background microflora of tomatoes. PMID:24929725

  9. Decolonisation of MRSA, S. aureus and E. coli by Cold-Atmospheric Plasma Using a Porcine Skin Model In Vitro

    PubMed Central

    Maisch, Tim; Shimizu, Tetsuji; Li, Yang-Fang; Heinlin, Julia; Karrer, Sigrid; Morfill, Gregor; Zimmermann, Julia L.

    2012-01-01

    In the last twenty years new antibacterial agents approved by the U.S. FDA decreased whereas in parallel the resistance situation of multi-resistant bacteria increased. Thus, community and nosocomial acquired infections of resistant bacteria led to a decrease in the efficacy of standard therapy, prolonging treatment time and increasing healthcare costs. Therefore, the aim of this work was to demonstrate the applicability of cold atmospheric plasma for decolonisation of Gram-positive (Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-sensitive Staphylococcus aureus) and Gram-negative bacteria (E. coli) using an ex vivo pig skin model. Freshly excised skin samples were taken from six month old female pigs (breed: Pietrain). After application of pure bacteria on the surface of the explants these were treated with cold atmospheric plasma for up to 15 min. Two different plasma devices were evaluated. A decolonisation efficacy of 3 log10 steps was achieved already after 6 min of plasma treatment. Longer plasma treatment times achieved a killing rate of 5 log10 steps independently from the applied bacteria strains. Histological evaluations of untreated and treated skin areas upon cold atmospheric plasma treatment within 24 h showed no morphological changes as well as no significant degree of necrosis or apoptosis determined by the TUNEL-assay indicating that the porcine skin is still vital. This study demonstrates for the first time that cold atmospheric plasma is able to very efficiently kill bacteria applied to an intact skin surface using an ex vivo porcine skin model. The results emphasize the potential of cold atmospheric plasma as a new possible treatment option for decolonisation of human skin from bacteria in patients in the future without harming the surrounding tissue. PMID:22558091

  10. Cold plasma inactivates Salmonella Stanley and Escherichia coli O157:H7 inoculated on golden delicious apples.

    PubMed

    Niemira, Brendan A; Sites, Joseph

    2008-07-01

    Cold plasma generated in a gliding arc was applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley on agar plates and inoculated onto the surfaces of Golden Delicious apples. This novel sanitizing technology inactivated both pathogens on agar plates, with higher flow rate (40 liters/min) observed to be more efficacious than were lower flow rates (20 liters/min), irrespective of treatment time (1 or 2 min). Golden Delicious apples were treated with various flow rates (10, 20, 30, or 40 liters/min) of cold plasma for various times (1, 2, or 3 min), applied to dried spot inoculations. All treatments resulted in significant (P < 0.05) reductions from the untreated control, with 40 liters/min more effective than were lower flow rates. Inactivation of Salmonella Stanley followed a time-dependent reduction for all flow rates. Reductions after 3 min ranged from 2.9 to 3.7 log CFU/ml, close to the limit of detection. For E. coli O157:H7, 40 liters/min gave similar reductions for all treatment times, 3.4 to 3.6 log CFU/ml. At lower flow rates, inactivation was related to exposure time, with 3 min resulting in reductions of 2.6 to 3 log CFU/ml. Temperature increase of the treated apples was related to exposure time for all flow rates. The maximum temperature of any plasma-treated apple was 50.8 degrees C (28 degrees C above ambient), after 20 liters/min for 3 min, indicating that antimicrobial effects were not the result of heat. These results indicate that cold plasma is a nonthermal process that can effectively reduce human pathogens inoculated onto fresh produce. PMID:18680933

  11. Observation of Solvent Penetration during Cold Denaturation of E. coli Phosphofructokinase-2

    PubMed Central

    Ramírez-Sarmiento, César A.; Baez, Mauricio; Wilson, Christian A.M.; Babul, Jorge; Komives, Elizabeth A.; Guixé, Victoria

    2013-01-01

    Phosphofructokinase-2 is a dimeric enzyme that undergoes cold denaturation following a highly cooperative N2 2I mechanism with dimer dissociation and formation of an expanded monomeric intermediate. Here, we use intrinsic fluorescence of a tryptophan located at the dimer interface to show that dimer dissociation occurs slowly, over several hours. We then use hydrogen-deuterium exchange mass spectrometry experiments, performed by taking time points over the cold denaturation process, to measure amide exchange throughout the protein during approach to the cold denatured state. As expected, a peptide corresponding to the dimer interface became more solvent exposed over time at 3°C; unexpectedly, amide exchange increased throughout the protein over time at 3°C. The rate of increase in amide exchange over time at 3°C was the same for each region and equaled the rate of dimer dissociation measured by tryptophan fluorescence, suggesting that dimer dissociation and formation of the cold denatured intermediate occur without appreciable buildup of folded monomer. The observation that throughout the protein amide exchange increases as phosphofructokinase-2 cold denatures provides experimental evidence for theoretical predictions that cold denaturation primarily occurs by solvent penetration into the hydrophobic core of proteins in a sequence-independent manner. PMID:23708365

  12. Synthesis of deuterium-labelled halogen derivatives of L-tryptophan catalysed by tryptophanase.

    PubMed

    Winnicka, Elżbieta; Szymańska, Jolanta; Kańska, Marianna

    2016-06-01

    The isotopomers of halogen derivatives of l-tryptophan (l-Trp) (4'-F-, 7'-F-, 5'-Cl- and 7'-Br-l-Trp), specifically labelled with deuterium in α-position of the side chain, were obtained by enzymatic coupling of the corresponding halogenated derivatives of indole with S-methyl-l-cysteine in (2)H2O, catalysed by enzyme tryptophanase (EC 4.1.99.1). The positional deuterium enrichment of the resulting tryptophan derivatives was controlled using (1)H NMR. In accordance with the mechanism of the lyase reaction, a 100% deuterium labelling was observed in the α-position; the chemical yields were between 23 and 51%. Furthermore, β-F-l-alanine, synthesized from β-F-pyruvic acid by the l-alanine dehydrogenase reaction, has been tested as a coupling agent to obtain the halogenated deuterium-labelled derivatives of l-Trp. The chemical yield (∼30%) corresponded to that as observed with S-methyl-l-cysteine but the deuterium label was only 63%, probably due to the use of a not completely deuterated incubation medium. PMID:26586366

  13. Probing bactericidal mechanisms induced by cold atmospheric plasmas with Escherichia coli mutants

    SciTech Connect

    Perni, Stefano; Shama, Gilbert; Hobman, J. L.; Lund, P. A.; Kershaw, C. J.; Hidalgo-Arroyo, G. A.; Penn, C. W.; Deng, X. T.; Walsh, J. L.; Kong, M. G.

    2007-02-12

    Mechanisms of plasma-induced microbial inactivation have commonly been studied with physicochemical techniques. In this letter, Escherichia coli K-12 and its {delta}recA, {delta}rpoS, and {delta}soxS mutants are employed to discriminate effects of UV photons, OH radicals, and reactive oxygen species produced in atmospheric discharges. This microbiological approach exploits the fact that these E. coli mutants are defective in their resistance against various external stresses. By interplaying bacterial inactivation kinetics with optical emission spectroscopy, oxygen atoms are identified as a major contributor in plasma inactivation with minor contributions from UV photons, OH radicals, singlet oxygen metastables, and nitric oxide.

  14. Probing bactericidal mechanisms induced by cold atmospheric plasmas with Escherichia coli mutants

    NASA Astrophysics Data System (ADS)

    Perni, Stefano; Shama, Gilbert; Hobman, J. L.; Lund, P. A.; Kershaw, C. J.; Hidalgo-Arroyo, G. A.; Penn, C. W.; Deng, X. T.; Walsh, J. L.; Kong, M. G.

    2007-02-01

    Mechanisms of plasma-induced microbial inactivation have commonly been studied with physicochemical techniques. In this letter, Escherichia coli K-12 and its ΔrecA, ΔrpoS, and ΔsoxS mutants are employed to discriminate effects of UV photons, OH radicals, and reactive oxygen species produced in atmospheric discharges. This microbiological approach exploits the fact that these E. coli mutants are defective in their resistance against various external stresses. By interplaying bacterial inactivation kinetics with optical emission spectroscopy, oxygen atoms are identified as a major contributor in plasma inactivation with minor contributions from UV photons, OH radicals, singlet oxygen metastables, and nitric oxide.

  15. Short pulse cold plasma treatment reduces Salmonella and E. coli O157:H7 on almonds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of dry nuts, including almonds is a food safety concern. A nonthermal method for reducing or eliminating is a desirable tool for producers and processors. Cold plasma is a novel antimicrobial intervention that can eliminate foodborne pathogens on produce. A key consideration for any tr...

  16. Expanded Monomeric Intermediate upon Cold and Heat Unfolding of Phosphofructokinase-2 from Escherichia coli

    PubMed Central

    Baez, Mauricio; Wilson, Christian A.M.; Ramírez-Sarmiento, César A.; Guixé, Victoria; Babul, Jorge

    2012-01-01

    Folding studies have been focused mainly on small, single-domain proteins or isolated single domains of larger proteins. However, most of the proteins present in biological systems are composed of multiple domains, and to date, the principles that underlie its folding remain elusive. The unfolding of Pfk-2 induced by GdnHCl has been described by highly cooperative three-state equilibrium (N2↔2I↔2U). This is characterized by a strong coupling between the subunits’ tertiary structure and the integrity of the dimer interface because “I” represents an unstructured and expanded monomeric intermediate. Here we report that cold and heat unfolding of Pfk-2 resembles the N2↔2I step of chemically induced unfolding. Moreover, cold unfolding appears to be as cooperative as that induced chemically and even more so than its heat-unfolding counterpart. Because Pfk-2 is a large homodimer of 66 kDa with a complex topology consisting of well-defined domains, these results are somewhat unexpected considering that cold unfolding has been described as a special kind of perturbation that decouples the cooperative unfolding of several proteins. PMID:23200052

  17. Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus

    PubMed Central

    Han, L.; Patil, S.; Milosavljević, V.; Cullen, P. J.

    2015-01-01

    Atmospheric cold plasma (ACP) is a promising nonthermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen-containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. Identification of ROS and an understanding of their role are important for advancing ACP applications for a range of complex microbiological issues. In this study, the inactivation efficacy of in-package high-voltage (80 kV [root mean square]) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed in which reactive species were found to either react primarily with the cell envelope or damage intracellular components. Escherichia coli was inactivated mainly by cell leakage and low-level DNA damage. Conversely, Staphylococcus aureus was mainly inactivated by intracellular damage, with significantly higher levels of intracellular ROS observed and little envelope damage. However, for both bacteria studied, increasing treatment time had a positive effect on the intracellular ROS levels generated. PMID:26519396

  18. Overproduction of anti-Tn antibody MLS128 single-chain Fv fragment in Escherichia coli cytoplasm using a novel pCold-PDI vector.

    PubMed

    Subedi, Ganesh P; Satoh, Tadashi; Hanashima, Shinya; Ikeda, Akemi; Nakada, Hiroshi; Sato, Reiko; Mizuno, Mamoru; Yuasa, Noriyuki; Fujita-Yamaguchi, Yoko; Yamaguchi, Yoshiki

    2012-03-01

    Overproduction of recombinant proteins in Escherichia coli is often hampered by their failure to fold correctly, leading to their accumulation within inclusion bodies. To overcome the problem, a variety of techniques aimed at soluble expression have been developed including low temperature expression and/or fusion of soluble tags and chaperones. However, a general protocol for bacterial expression of disulfide bond-containing proteins has hitherto not been established. Single chain Fv fragments (scFvs) are disulfide bond-containing proteins often difficult to express in soluble forms in E. coli. We here examine in detail the E. coli expression of a scFv originating from an anti-carbohydrate MLS128 antibody as a model system. We combine three techniques: (1) tagging scFv with thioredoxin, DsbC and protein disulfide isomerase (PDI), (2) expressing the proteins at low temperature using the pCold vector system, and (3) using Origami E. coli strains with mutations in the thioredoxin reductase and glutathione reductase genes. We observed a high expression level of soluble MLS128-scFv in the Origami strain only when PDI is used as a tag. The recombinant protein retains full binding activity towards synthetic carbohydrate antigens. The developed "pCold-PDI" vector has potential for overproduction of other scFvs and disulfide-containing proteins in the Origami strains. PMID:22245752

  19. Cold plasma inactivation of internalised bacteria and biofilms for Salmonella enterica serovar Typhimurium, Listeria monocytogenes and Escherichia coli.

    PubMed

    Ziuzina, Dana; Han, Lu; Cullen, Patrick J; Bourke, Paula

    2015-10-01

    Microbial biofilms and bacteria internalised in produce tissue may reduce the effectiveness of decontamination methods. In this study, the inactivation efficacy of in-package atmospheric cold plasma (ACP) afterglow was investigated against Salmonella Typhimurium, Listeria monocytogenes and Escherichia coli in the forms of planktonic cultures, biofilms formed on lettuce and associated bacteria internalised in lettuce tissue. Prepared lettuce broth (3%) was inoculated with bacteria resulting in a final concentration of ~7.0 log10 CFU/ml. For biofilm formation and internalisation, lettuce pieces (5 × 5 cm) were dip-inoculated in bacterial suspension of ~7.0 log10 CFU/ml for 2 h and further incubated for 0, 24 and 48 h at either 4 °C or room temperature (~22 °C) in combination with light/dark photoperiod or at 4 °C under dark conditions. Inoculated samples were sealed inside a rigid polypropylene container and indirectly exposed (i.e. placed outside plasma discharge) to a high voltage (80 kVRMS) air ACP with subsequent storage for 24 h at 4 °C. ACP treatment for 30s reduced planktonic populations of Salmonella, L. monocytogenes and E. coli suspended in lettuce broth to undetectable levels. Depending on storage conditions, bacterial type and age of biofilm, 300 s of treatment resulted in reduction of biofilm populations on lettuce by a maximum of 5 log10 CFU/sample. Scanning electron and confocal laser microscopy pointed to the incidence of bacterial internalisation and biofilm formation, which influenced the inactivation efficacy of ACP. Measured intracellular reactive oxygen species (ROS) revealed that the presence of organic matter in the bacterial suspension might present a protective effect against the action of ROS on bacterial cells. This study demonstrated that high voltage in-package ACP could be a potential technology to overcome bacterial challenges associated with food produce. However, the existence of biofilms and internalised bacteria should be

  20. Differences in inactivation of Escherichia coli O157:H7 strains in ground beef following repeated high pressure processing treatments and cold storage.

    PubMed

    Zhou, Yijing; Karwe, Mukund V; Matthews, Karl R

    2016-09-01

    High pressure processing (HPP) is a safe non-thermal processing method to effectively improve food safety. In this study, HPP treatment followed by cold storage was investigated to reduce Escherichia coli O157:H7 in ground beef. Experiments were conducted using ground beef contaminated with six E. coli O157:H7 strains one at a time or as a cocktail. Control and inoculated ground beef samples were HPP at 25 °C, 35 °C, and 45 °C, at 400 MPa and pre-determined number of pressure cycles totaling a holding time of 15 min. Optimum HPP parameters were 25 °C, 400 MPa at five pressure cycles of 3 min each which achieved a 5-log reduction of E. coli O157:H7 in ground beef. Storing HPP processed ground beef at 4 °C or -20 °C further decreased (P < 0.05) the E. coli O157:H7 population. An effective HPP treatment (5-log reduction) was developed that could be used post-processing to reduce the risk associated with E. coli O157:H7 contamination in ground beef. PMID:27217352

  1. Interrelated Effects of Cold Shock and Osmotic Pressure on the Permeability of the Escherichia coli Membrane to Permease Accumulated Substrates1

    PubMed Central

    Leder, Irwin G.

    1972-01-01

    Permease studies are generally carried out by incubating cells in growth medium with labeled substrate, collecting the cells on microporous membrane filters, and washing them free from extracellular radioactivity with ice-cold medium. Studies of thiomethylgalactoside, valine, and galactose accumulation indicate that in several strains of Escherichia coli the bacterial membrane is exquisitely sensitive to isosmotic cold shock. Substrate pools formed at 25 C may suffer almost total loss if the cells are rapidly chilled to approximately 0 C during sampling. In glycerol-grown cells, this rapid efflux of substrate is prevented or minimized if the cells are subjected at the moment of cold shock to a simultaneous hyperosmotic transition. Because of this protective effect, the apparent size of a permease accumulated substrate pool is extremely sensitive to the osmotic composition of the incubation medium and may appear to be increased as much as 10-fold when the osmolarity is reduced from approximately 0.3 to 0.1 osmolar. These differences vanish when sampling and washing are carried out with medium at room temperature. It is suggested that isosmotic cold shock causes crystallization of the liquid-like lipids within the membrane. The hydrophilic channels created in this process would facilitate the rapid efflux of permease accumulated substrates. The imposition of a simultaneous hyperosmotic transition by dehydrating the cell periphery would cause increased lipid interaction, thus preserving the integrity of the cells membrane. PMID:4591477

  2. Survival and Reduction of Shiga Toxin-Producing Escherichia coli in a Fresh Cold-Pressed Juice Treated with Antimicrobial Plant Extracts.

    PubMed

    Hatab, Shaimaa; Athanasio, Renata; Holley, Richard; Rodas-Gonzalez, Argenis; Narvaez-Bravo, Claudia

    2016-08-01

    This study was conducted to evaluate the survival of 7 Shiga-toxigenic Escherichia coli (STEC) in fresh cold-pressed juice and the antimicrobial efficacy of 4 essential oils (EO: achillea, rosemary, sage, and thyme). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each EO was determined using microdilution assays evaluated at pH levels 4 and 7; as well as at 4 and 25 °C; daily for up to 5 d. Results indicated that 5 of 7 serotypes survived well in cold-pressed raw juice for at least 4 d at 4 °C and pH 3.5 with no significant (P > 0.05) reduction in viability. The EO showed varying degrees of antimicrobial activity against the 7 STEC. The MIC and MBCs were lowest for thyme (2 μg/L) and highest for sage (15 to 25 μg/L). The antimicrobial activity was enhanced at low pH and temperature. Data showed that although the top 7 STEC could survive low pH and temperature in vitro and in cold-pressed juices, EO, especially from thyme and rosemary, reduced STEC to an undetectable level at 4 °C, suggesting that they could be used as natural antimicrobials in juice. PMID:27399584

  3. Thermal inactivation of acid, cold, heat, starvation, and desiccation stress-adapted Escherichia coli O157:H7 in moisture-enhanced nonintact beef.

    PubMed

    Shen, Cangliang; Geornaras, Ifigenia; Belk, Keith E; Smith, Gary C; Sofos, John N

    2011-04-01

    This study was conducted to compare thermal inactivation of stress-adapted and nonadapted Escherichia coli O157:H7 in nonintact beef moisture enhanced with different brine formulations and cooked to 65°C. Coarsely ground beef was mixed with acid, cold, heat, starvation, or desiccation stress-adapted or nonadapted rifampin-resistant E. coli O157:H7 (eight-strain mixture, 5 to 6 log CFU/g) and a brine solution for a total moisture enhancement level of 10%. The brine treatments included distilled water (control), sodium chloride (0.5% NaCl) plus sodium tripolyphosphate (0.25% STP), or NaCl + STP combined with cetylpyridinium chloride (0.2% CPC), lactic acid (0.3% LA), or sodium metasilicate (0.2% SM). The treated meat was extruded into bags (15 cm diameter), semifrozen (-20°C for 4.5 h), and cut into 2.54-cm (1-in.)-thick portions. Samples were individually vacuum packaged, frozen (-20°C for 42 h), and tempered at 4°C for 2.5 h before cooking. Partially thawed (-1.8 ± 0.4°C) samples were pan broiled to an internal temperature of 65°C. Pathogen counts of partially thawed (before cooking) samples moisture enhanced with brines containing CPC, LA, or SM were 0.7 to 1.1, 0.0 to 0.4, and 0.2 to 0.4 log CFU/g, respectively, lower than those of the control. Compared with microbial count reductions obtained after pan broiling of beef inoculated with nonadapted E. coli O157:H7 cells, count reductions during cooking of meat inoculated with cold and desiccation stress-adapted, acid stress-adapted, and heat and starvation stress-adapted cells indicated sensitization, cross protection, and no effect, respectively, of these stresses on the pathogen during subsequent exposure to heat. Among all stressed cultures, CPC-treated samples (0.8 to 3.6 log CFU/g) and LA-treated samples (0.8 to 3.5 log CFU/g) had the lowest numbers of E. coli O157:H7 survivors after cooking. PMID:21477465

  4. Cold plasma rapid decontamination of food contact surfaces contaminated with Salmonella and Escherichia coli 0157:H7

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cross-contamination of fresh produce from persistent pathogen reservoirs is a known risk factor in processing environments. Industry requires a waterless, zero-contact, chemical-free method for removing pathogens from food-contact surfaces. Cold plasma was tested for its ability to remove biofilms f...

  5. Extracellular secretion of Pseudoalteromonas sp. cold-adapted esterase in Escherichia coli in the presence of Pseudoalteromonas sp. components of ABC transport system.

    PubMed

    Długołecka, Anna; Cieśliński, Hubert; Turkiewicz, Marianna; Białkowska, Aneta M; Kur, Józef

    2008-12-01

    Recently we described identification and characterization of GDSL esterase EstA from psychrotrophic bacterium Pseudoalteromonas sp. 643A. Attempts to obtain heterologous overexpression of this enzyme in Escherichia coli system were not satisfactory. The EstA protein was expressed as inclusion bodies, most of that were inactive after purification step, and the recovery of esterolytic activity was very low after refolding. Based on the sequence analysis we found that the esterase EstA gene is clustered with three genes encoding components of ABC transport system. These genes, designated abc1, abc2, and abc3 encode an ATP-binding protein (ABC1) and two permease proteins (ABC2 and ABC3). In present study, to obtain larger amounts of the active cold-adapted EstA esterase from Pseudoalteromonas sp. 643A, we designed a two-plasmid E. coli expression system where the gene encoding EstA enzyme was cloned into pET30b(+) expression vector and three genes encoding components of ABC transport system were cloned into pACYC-pBAD vector. It was shown that the created expression system was useful for extracellular production of active EstA enzyme which was purified from the culture medium. In the presence of all the three transporter proteins the secretion of EstA was at the highest level. When one or two of these components were missing, EstA secretion was also possible, but not so effective. It indicates that ABC2 and ABC3 proteins of Pseudoalteromonas sp. 643A could be replaced with their homologous proteins of E. coli. PMID:18700165

  6. Production of anteiso-branched fatty acids in Escherichia coli; next generation biofuels with improved cold-flow properties.

    PubMed

    Haushalter, Robert W; Kim, Woncheol; Chavkin, Ted A; The, Lionadi; Garber, Megan E; Nhan, Melissa; Adams, Paul D; Petzold, Christopher J; Katz, Leonard; Keasling, Jay D

    2014-11-01

    Microbial fermentation is emerging as an increasingly important resource for the production of fatty acids to serve as precursors for renewable diesel as well as detergents, lubricants and other industrial chemicals, as an alternative to traditional sources of reduced carbon such as petroleum. A major disadvantage of fuels derived from biological sources is their undesirable physical properties such as high cloud and pour points, and high viscosity. Here we report the development of an Escherichia coli strain that efficiently produces anteiso-branched fatty acids, which can be converted into downstream products with lower cloud and pour points than the mixtures of compounds produced via the native metabolism of the cell. This work addresses a serious limitation that must be overcome in order to produce renewable biodiesel and oleochemicals that perform as well as their petroleum-based counterparts. PMID:25250846

  7. Differences in properties between human alphaA- and alphaB-crystallin proteins expressed in Escherichia coli cells in response to cold and extreme pH.

    PubMed Central

    Takeuchi, Satoru; Mandai, Yumi; Otsu, Akiko; Shirakawa, Taro; Masuda, Katsuyoshi; Chinami, Masanobu

    2003-01-01

    It has been reported that alphaA-crystallin has greater protective effects against apoptosis in lens epithelial cells than alphaB-crystallin [Andley, Song, Wawrousek, Fleming and Bassnett (2000) J. Biol. Chem. 275, 36823-36831]. Because the alphaA-crystallin proteins are specifically expressed in the vertebrate lens, we examine the non-specific properties of both alphaA- and alphaB-crystallins in an Escherichia coli system. E. coli cells were transformed with the inducible protein expression vector pET-11a, harbouring the gene for either human alphaA- or alphaB-crystallin, and two other control plasmids, pET-1la vector alone or pGEX-2T vector encoding GST (glutathione S-transferase). These cells were exposed to various stress conditions, such as cold-shock at 4 degrees C or extremely low or high pH environments (pH 4.7 or pH 8.0) for 6 h, and survival of the host cells and the solubility of the expressed target proteins in the cytosol were examined. Under these stress conditions, the cells expressing alphaB-crystallin protein demonstrated significantly improved survival when compared with the other cells, and the expressed protein in the cytosol was almost soluble, in contrast with the alphaA-crystallin protein. Differences in the amino acid sequence between the proteins in a phenylalanine-rich region next to the N-terminal consensus alpha-crystallin domain was considered to be responsible for chaperone activity and cell survival. PMID:12826011

  8. Acquisition of double-stranded DNA-binding ability in a hybrid protein between Escherichia coli CspA and the cold shock domain of human YB-1.

    PubMed

    Wang, N; Yamanaka, K; Inouye, M

    2000-11-01

    Escherichia coli CspA, a major cold shock protein, is dramatically induced upon temperature downshift. As it binds co-operatively to single-stranded DNA (ssDNA) and RNA without apparent sequence specificity, it has been proposed that CspA acts as an RNA chaperone to facilitate transcription and translation at low temperature. CspA consists of a five-stranded beta-barrel structure containing two RNA-binding motifs, RNP1 and RNP2. Eukaryotic Y-box proteins, such as human YB-1, are a family of nucleic acid-binding proteins that share a region of high homology with CspA (43% identity), termed the cold shock domain (CSD). Their cellular functions are very diverse and are associated with growth-related processes. Here, we replaced the six-residue loop region of CspA between the beta3 and beta4 strands with the corresponding region of the CSD of human YB-1 protein. The resulting hybrid protein became capable of binding to double-stranded DNA (dsDNA) in addition to ssDNA and RNA. The dsDNA-binding ability of an RNP1 point mutant (F20L) of the hybrid was almost unchanged. On the other hand, the dsDNA-binding ability of the hybrid protein was abolished in high salt concentrations in contrast to its ssDNA-binding ability. These results indicate that the loop region between the beta3 and beta4 strands of Y-box proteins, which is a little longer and more basic than that of CspA, plays an important role in their binding to dsDNA. PMID:11069676

  9. Efficacy of a novel prebiotic and a commercial probiotic in reducing mortality and production losses due to cold stress and Escherichia coli challenge of broiler chicks 1.

    PubMed

    Huff, G R; Huff, W E; Rath, N C; El-Gohary, F A; Zhou, Z Y; Shini, S

    2015-05-01

    Prebiotics consisting of resistant starch may alter intestinal ecology, thus modulating inflammation and increasing intestinal health through increased cecal production of short-chain fatty acids (SCFA). Probiotics may directly alter the intestinal microbiome, resulting in the same effects. We hypothesize that adding prebiotics and probiotics to feed may protect the gut of young chicks under stress. Studies 1, 2, and 3 evaluated treatments in a cold stress (CS) and Escherichia coli (EC) oral challenge to 430 day-old broiler chicks for 3 wk. In study 1, prebiotics were administered as 15% of the diet during the first week only and consisted of the following: Hi-Maize resistant starch (HM), potato starch (PS), or raw potato (RP). In studies 2 and 3, the PS treatment was identical to study 1, and an additional probiotic treatment (PRO) was administered in feed and water. In study 1, PS protected BW during the first week and decreased the mortality of CS/EC-challenged birds during the first week and wk 3, while RP decreased the mortality of warm-brooded birds challenged with EC during the first week. In study 2, PS decreased and PRO increased the main effect mean (MEM) of the first week BW. PS and PRO numerically decreased the feed conversion ratio (FCR) by 23 and 29 points, respectively, in CS/EC-challenged birds with no effects on mortality. In study 3, PS decreased and PRO increased the first week and wk 3 MEM BW. PS numerically increased FCR by 16 points, while PRO decreased FCR by 2 points. Both PS and PRO tended to increase overall mortality, and PRO significantly increased mortality in the CS/EC challenge. These results suggest that the effects of PS may be too variable in this challenge model for further study; however, the PRO treatment improved production values and may have potential as an alternative to antibiotics during the first weeks after hatch. PMID:25743418

  10. Escherichia coli (E. coli)

    MedlinePlus

    ... so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the ... at CDC Foodborne disease Travelers' Health: Safe Food & Water Healthy Swimming E. coli Infection & Farm ... Word file Microsoft Excel file Audio/Video file Apple ...

  11. Cold Sores

    MedlinePlus

    ... delivered directly to your desktop! more... What Are Cold Sores? Article Chapters What Are Cold Sores? Cold ... January 2012 Previous Next Related Articles: Canker and Cold Sores Aloe Vera May Help Relieve Mouth Sores ...

  12. Genome-scale thermodynamic analysis of Escherichia coli metabolism.

    PubMed

    Henry, Christopher S; Jankowski, Matthew D; Broadbelt, Linda J; Hatzimanikatis, Vassily

    2006-02-15

    Genome-scale metabolic models are an invaluable tool for analyzing metabolic systems as they provide a more complete picture of the processes of metabolism. We have constructed a genome-scale metabolic model of Escherichia coli based on the iJR904 model developed by the Palsson Laboratory at the University of California at San Diego. Group contribution methods were utilized to estimate the standard Gibbs free energy change of every reaction in the constructed model. Reactions in the model were classified based on the activity of the reactions during optimal growth on glucose in aerobic media. The most thermodynamically unfavorable reactions involved in the production of biomass in E. coli were identified as ATP phosphoribosyltransferase, ATP synthase, methylene-tetra-hydrofolate dehydrogenase, and tryptophanase. The effect of a knockout of these reactions on the production of biomass and the production of individual biomass precursors was analyzed. Changes in the distribution of fluxes in the cell after knockout of these unfavorable reactions were also studied. The methodologies and results discussed can be used to facilitate the refinement of the feasible ranges for cellular parameters such as species concentrations and reaction rate constants. PMID:16299075

  13. E. Coli

    MedlinePlus

    ... E. coli is short for the medical term Escherichia coli . The strange thing about these bacteria — and lots ... cause a very serious infection. Someone who has E. coli infection may have these symptoms: bad stomach cramps and ...

  14. Common cold

    MedlinePlus

    ... are the most common reason that children miss school and parents miss work. Parents often get colds ... other children. A cold can spread quickly through schools or daycares. Colds can occur at any time ...

  15. Common Cold

    MedlinePlus

    ... coughing - everyone knows the symptoms of the common cold. It is probably the most common illness. In ... people in the United States suffer 1 billion colds. You can get a cold by touching your ...

  16. Cold Stress

    MedlinePlus

    ... be at risk of cold stress. Extreme cold weather is a dangerous situation that can bring on ... the country. In regions relatively unaccustomed to winter weather, near freezing temperatures are considered factors for cold ...

  17. Cold intolerance

    MedlinePlus

    ... intolerance is an abnormal sensitivity to a cold environment or cold temperatures. ... can be a symptom of a problem with metabolism. Some people (often very thin women) do not tolerate cold environments because they have very little body fat and ...

  18. Common Cold

    MedlinePlus

    ... News & Events Volunteer NIAID > Health & Research Topics > Common Cold Skip Website Tools Website Tools Print this page ... Help people who are suffering from the common cold by volunteering for NIAID clinical studies on ClinicalTrials. ...

  19. Catabolite repression in Escherichia coli. A study of two hypotheses

    PubMed Central

    Moses, V.; Yudkin, M. D.

    1968-01-01

    1. Two hypotheses to account for general catabolite repression of the lactose enzymes in Escherichia coli were tested: the dilution model of Palmer & Moses (1967), and the specific catabolite repressor model of Loomis & Magasanik (1965, 1967). 2. The dilution model predicts that in mutants lacking the i–o regulation system the differential rate of β-galactosidase synthesis should increase when amino acid-synthesizing enzymes are repressed by the presence of amino acids in the medium. It also predicts that with such mutants the total absence of Pi from the medium should not result in the complete cessation of β-galactosidase synthesis that is observed with wild-type cells. 3. Neither prediction was confirmed experimentally, and it is concluded that this model cannot explain catabolite repression. 4. The specific repressor hypothesis depends on the properties of a strain of E. coli carrying the CR− mutation. It requires both that cells of this genotype should be totally resistant to general catabolite repression and that this resistance should be specific for the lactose enzymes. 5. In fact the synthesis of β-galactosidase by CR− cells, though showing resistance to catabolite repression by growth on glucose, was found to be repressed in several other circumstances. 6. Two other inducible enzymes, l-tryptophanase and d-serine deaminase, also showed resistance to repression by glucose in CR− cells. 7. It is concluded that this model, too, does not account for general catabolite repression. 8. Strains carrying deletions at either end of the lactose operon that extend into the structural genes of the operon continue to exhibit catabolite repression. 9. These experiments appear to eliminate the possibility that catabolite repression operates at the level of DNA transcription, and suggest that repression affects instead the translation of messenger RNA into protein. PMID:4881142

  20. Dextran Sodium Sulfate-Induced Inflammation Alters the Expression of Proteins by Intestinal Escherichia coli Strains in a Gnotobiotic Mouse Model

    PubMed Central

    Schumann, Sara; Alpert, Carl; Engst, Wolfram; Loh, Gunnar

    2012-01-01

    To identify Escherichia coli proteins involved in adaptation to intestinal inflammation, mice were monoassociated with the colitogenic E. coli strain UNC or with the probiotic E. coli strain Nissle. Intestinal inflammation was induced by treating the mice with 3.5% dextran sodium sulfate (DSS). Differentially expressed proteins in E. coli strains collected from cecal contents were identified by 2-dimensional difference gel electrophoresis. In both strains, acute inflammation led to the downregulation of pathways involved in carbohydrate breakdown and energy generation. Accordingly, DSS-treated mice had lower concentrations of bacterial fermentation products in their cecal contents than control mice. Differentially expressed proteins also included the Fe-S cluster repair protein NfuA, the tryptophanase TnaA, and the uncharacterized protein YggE. NfuA expression was 3-fold higher in E. coli strains from DSS-treated than from control mice. Reporter experiments confirmed the induction of nfuA in response to iron deprivation, mimicking Fe-S cluster destruction by inflammation. YggE expression, which has been reported to reduce the intracellular level of reactive oxygen species, was 4- to 8-fold higher in E. coli Nissle than in E. coli UNC. This was confirmed by in vitro reporter gene assays indicating that Nissle is better equipped to cope with oxidative stress than UNC. Nissle isolated from DSS-treated and control mice had TnaA levels 4- to 7-fold-higher than those of UNC. Levels of indole resulting from the TnaA reaction were higher in control animals associated with E. coli Nissle. Because of its anti-inflammatory effect, indole is hypothesized to be involved in the extension of the remission phase in ulcerative colitis described for E. coli Nissle. PMID:22210207

  1. Cold plasma decontamination of foods.

    PubMed

    Niemira, Brendan A

    2012-01-01

    Cold plasma is a novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables. This flexible sanitizing method uses electricity and a carrier gas, such as air, oxygen, nitrogen, or helium; antimicrobial chemical agents are not required. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization process. A wide array of cold plasma systems that operate at atmospheric pressures or in low pressure treatment chambers are under development. Reductions of greater than 5 logs can be obtained for pathogens such as Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus. Effective treatment times can range from 120 s to as little as 3 s, depending on the food treated and the processing conditions. Key limitations for cold plasma are the relatively early state of technology development, the variety and complexity of the necessary equipment, and the largely unexplored impacts of cold plasma treatment on the sensory and nutritional qualities of treated foods. Also, the antimicrobial modes of action for various cold plasma systems vary depending on the type of cold plasma generated. Optimization and scale up to commercial treatment levels require a more complete understanding of these chemical processes. Nevertheless, this area of technology shows promise and is the subject of active research to enhance efficacy. PMID:22149075

  2. Common cold

    MedlinePlus

    ... often causes a runny nose, nasal congestion, and sneezing. You may also have a sore throat, cough, ... symptoms are: Nasal congestion Runny nose Scratchy throat Sneezing Adults and older children with colds generally have ...

  3. Cold Intolerance

    MedlinePlus

    ... from the Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors © Cold Intolerance Many polio ... index of Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors © Back to top Contact ...

  4. Altered expression level of Escherichia coli proteins in response to treatment with the antifouling agent zosteric acid sodium salt.

    PubMed

    Villa, Federica; Remelli, William; Forlani, Fabio; Vitali, Alberto; Cappitelli, Francesca

    2012-07-01

    Zosteric acid sodium salt is a powerful antifouling agent. However, the mode of its antifouling action has not yet been fully elucidated. Whole cell proteome of Escherichia coli was analysed to study the different protein patterns expressed by the surface-exposed planktonic cells without and with sublethal concentrations of the zosteric acid sodium salt. Proteomic analysis revealed that at least 27 proteins showed a significant (19 upregulated and 8 downregulated, P < 0.001) altered expression level in response to the antifoulant. The proteomic signatures of zosteric acid sodium salt-treated cells are characterized by stress-associated (e.g. AhpC, OsmC, SodB, GroES, IscU, DnaK), motility-related (FliC), quorum-sensing-associated (LuxS) and metabolism/biosynthesis-related (e.g. PptA, AroA, FabD, FabB, GapA) proteins. Consistent with the overexpression of LuxS enzyme, the antifouling agent increased autoinducer-2 (AI-2) concentration by twofold. Moreover, treated cells experienced a statistically significant but modest increase of reactive oxygen species (+ 23%), tryptophanase (1.2-fold) and indole (1.2-fold) synthesis. Overall, our data suggest that zosteric acid sodium salt acts as environmental cue leading to global stress on E. coli cells, which favours the expression of various protective proteins, the AI-2 production and the synthesis of flagella, to escape from adverse conditions. PMID:22176949

  5. Rational elicitation of cold-sensitive phenotypes.

    PubMed

    Baliga, Chetana; Majhi, Sandipan; Mondal, Kajari; Bhattacharjee, Antara; VijayRaghavan, K; Varadarajan, Raghavan

    2016-05-01

    Cold-sensitive phenotypes have helped us understand macromolecular assembly and biological phenomena, yet few attempts have been made to understand the basis of cold sensitivity or to elicit it by design. We report a method for rational design of cold-sensitive phenotypes. The method involves generation of partial loss-of-function mutants, at either buried or functional sites, coupled with selective overexpression strategies. The only essential input is amino acid sequence, although available structural information can be used as well. The method has been used to elicit cold-sensitive mutants of a variety of proteins, both monomeric and dimeric, and in multiple organisms, namely Escherichia coli, Saccharomyces cerevisiae, and Drosophila melanogaster This simple, yet effective technique of inducing cold sensitivity eliminates the need for complex mutations and provides a plausible molecular mechanism for eliciting cold-sensitive phenotypes. PMID:27091994

  6. Cold injuries.

    PubMed

    Long, William B; Edlich, Richard F; Winters, Kathryne L; Britt, L D

    2005-01-01

    Exposure to cold can produce a variety of injuries that occur as a result of man's inability to adapt to cold. These injuries can be divided into localized injury to a body part, systemic hypothermia, or a combination of both. Body temperature may fall as a result of heat loss by radiation, evaporation, conduction, and convection. Hypothermia or systemic cold injury occurs when the core body temperature has decreased to 35 degrees C (95 degrees F) or less. The causes of hypothermia are either primary or secondary. Primary, or accidental, hypothermia occurs in healthy individuals inadequately clothed and exposed to severe cooling. In secondary hypothermia, another illness predisposes the individual to accidental hypothermia. Hypothermia affects multiple organs with symptoms of hypothermia that vary according to the severity of cold injury. The diagnosis of hypothermia is easy if the patient is a mountaineer who is stranded in cold weather. However, it may be more difficult in an elderly patient who has been exposed to a cold environment. In either case, the rectal temperature should be checked with a low-reading thermometer. The general principals of prehospital management are to (1) prevent further heat loss, (2) rewarm the body core temperature in advance of the shell, and (3) avoid precipitating ventricular fibrillation. There are two general techniques of rewarming--passive and active. The mechanisms of peripheral cold injury can be divided into phenomena that affect cells and extracellular fluids (direct effects) and those that disrupt the function of the organized tissue and the integrity of the circulation (indirect effects). Generally, no serious damage is seen until tissue freezing occurs. The mildest form of peripheral cold injury is frostnip. Chilblains represent a more severe form of cold injury than frostnip and occur after exposure to nonfreezing temperatures and damp conditions. Immersion (trench) foot, a disease of the sympathetic nerves and blood

  7. E. Coli and Pregnancy

    MedlinePlus

    ... care provider. What is E. coli? E. coli (Escherichia coli) is a bacterium that lives in your colon ( ... 10):1411-1413. Jones B, et al. 2004. Escherichia coli: a growing problem in early onset neonatal sepsis. ...

  8. E. Coli Infection

    MedlinePlus

    ... is E. coli? E. coli is short for Escherichia coli -- bacteria (germs) that cause severe cramps and diarrhea. E. ... and especially in people who have another illness. E. coli infection is more common during the summer months and ...

  9. COLD TRAP

    DOEpatents

    Milleron, N.

    1963-03-12

    An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)

  10. E. coli

    MedlinePlus

    ... sure that ground beef has reached a safe internal temperature of 160° F. Wash hands before preparing food, after diapering infants, and after contact with cows, sheep, or goats, their food or treats, or their living environment . General Information E. coli Infections (NIH MedlinePlus) Trusted ...

  11. Escherichia Coli

    ERIC Educational Resources Information Center

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  12. Project COLD.

    ERIC Educational Resources Information Center

    Kazanjian, Wendy C.

    1982-01-01

    Describes Project COLD (Climate, Ocean, Land, Discovery) a scientific study of the Polar Regions, a collection of 35 modules used within the framework of existing subjects: oceanography, biology, geology, meterology, geography, social science. Includes a partial list of topics and one activity (geodesic dome) from a module. (Author/SK)

  13. Cold Sores

    MedlinePlus

    ... causes oral herpes, or cold sores. Type 1 herpes virus infects more than half of the U.S. population by the time they reach their 20s. Type 2 usually affects the genital area Some people have no symptoms from the ...

  14. Hot, Cold, and Really Cold.

    ERIC Educational Resources Information Center

    Leyden, Michael

    1997-01-01

    Describes a physics experiment investigating temperature prediction and the relationship between the physical properties of heat units, melting, dissolving, states of matter, and energy loss. Details the experimental setup, which requires hot and cold water, a thermometer, and ice. Notes that the experiment employs a deliberate counter-intuitive…

  15. Chilling Out with Colds

    MedlinePlus

    ... most common cold virus, but more than 200 viruses can cause colds. Because there are so many, ... to help you feel better. Take that, cold viruses! continue How Kids Catch Colds Mucus (say: MYOO- ...

  16. Coping with Cold Sores

    MedlinePlus

    ... Here's Help White House Lunch Recipes Coping With Cold Sores KidsHealth > For Kids > Coping With Cold Sores ... sore." What's that? Adam wondered. What Is a Cold Sore? Cold sores are small blisters that is ...

  17. COLD TRAPS

    DOEpatents

    Thompson, W.I.

    1958-09-30

    A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

  18. E. coli enteritis

    MedlinePlus

    Traveler's diarrhea - E. coli ; Food poisoning - E. coli ; E. coli diarrhea; Hamburger disease ... infected. The most common symptom is sudden, severe diarrhea that is often bloody. Other symptoms may include: ...

  19. Cold symptoms (image)

    MedlinePlus

    Colds are caused by a virus and can occur year-round. The common cold generally involves a runny nose, nasal congestion, and ... symptoms include sore throat, cough, and headache. A cold usually lasts about 7 days, with perhaps a ...

  20. Colds and flus - antibiotics

    MedlinePlus

    Antibiotics - colds and flu ... treat infections that are caused by a virus. Colds and flu are caused by viruses. If you ... Hamilton A. Treatments for symptoms of the common cold. Am Fam Physician. 2013;88(12):Online. PMID: ...

  1. Vitamin C and colds

    MedlinePlus

    Colds and vitamin C ... belief that vitamin C can cure the common cold , research about this claim is conflicting. Large doses ... vitamin C may help reduce how long a cold lasts, but they do not appear to protect ...

  2. Cough & Cold Medicine Abuse

    MedlinePlus

    ... I Help a Friend Who Cuts? Cough & Cold Medicine Abuse KidsHealth > For Teens > Cough & Cold Medicine Abuse ... DXM Why Do People Use Cough and Cold Medicines to Get High? There's an ingredient in many ...

  3. Cold Atoms

    NASA Astrophysics Data System (ADS)

    Bellac, Michel Le

    2014-11-01

    This chapter and the following one address collective effects of quantum particles, that is, the effects which are observed when we put together a large number of identical particles, for example, electrons, helium-4 or rubidium-85 atoms. We shall see that quantum particles can be classified into two categories, bosons and fermions, whose collective behavior is radically different. Bosons have a tendency to pile up in the same quantum state, while fermions have a tendency to avoid each other. We say that bosons and fermions obey two different quantum statistics, the Bose-Einstein and the Fermi-Dirac statistics, respectively. Temperature is a collective effect, and in Section 5.1 we shall explain the concept of absolute temperature and its relation to the average kinetic energy of molecules. We shall describe in Section 5.2 how we can cool atoms down thanks to the Doppler effect, and explain how cold atoms can be used to improve the accuracy of atomic clocks by a factor of about 100. The effects of quantum statistics are prominent at low temperatures, and atom cooling will be used to obtain Bose-Einstein condensates at low enough temperatures, when the atoms are bosons.

  4. Cold energy

    NASA Astrophysics Data System (ADS)

    Wallace, John P.

    2015-12-01

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  5. Cold energy

    SciTech Connect

    Wallace, John P.

    2015-12-04

    Deviations in Q for resonant superconducting radio frequency niobium accelerator cavities are generally correlated with resistivity loss mechanisms. Field dependent Qs are not well modeled by these classical loss mechanisms, but rather can represent a form of precision cavity surface thermometry. When the field dependent Q variation shows improvement with increasing B field level the classical treatment of this problem is inadequate. To justify this behavior hydrogen as a ubiquitous impurity in niobium, which creates measurable property changes, even at very low concentrations is typically considered the cause of such anomalous behavior. This maybe the case in some instances, but more importantly any system operating with a highly coherent field with a significant time dependent magnetic component at near 2° K will have the ability to organize the remaining free spins within the London penetration depth to form a coupled energy reservoir in the form of low mass spin waves. The niobium resonant cavities are composed of a single isotope with a large nuclear spin. When the other loss mechanisms are stripped away this may be the gain medium activated by the low level residual magnetic fields. It was found that one resonant cavity heat treatment produced optimum surface properties and then functioned as a MASER extracting energy from the 2° K thermal bath while cooling the cavity walls. The cavity operating in this mode is a simulator of what can take place in the wider but not colder universe using the cosmic microwave background (CMB) as a thermal source. The low mass, long lifetimes, and the scale of the magnetic spin waves on the weakly magnetized interstellar medium allows energy to be stored that is many orders of magnitude colder than the cosmic microwave background. A linear accelerator cavity becomes a tool to explore the properties of the long wave length magnetic spin waves that populate this cold low energy regime.

  6. Diarrheagenic Escherichia coli

    PubMed Central

    Nataro, James P.; Kaper, James B.

    1998-01-01

    Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler’s diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (enteropathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens. PMID:9457432

  7. Action of sodium deoxycholate on Escherichia coli

    SciTech Connect

    D'Mello, A.; Yotis, W.W.

    1987-08-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

  8. E. Coli Infections

    MedlinePlus

    ... adults with weak immune systems. You can get E. coli infections by eating foods containing the bacteria. Symptoms of ... pool contaminated with human waste. Most cases of E. coli infection get better without treatment in 5 to 10 ...

  9. Cold plasma technologies for the inactivation of human pathogens on fresh and fresh-cut produce

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research in cold plasma processing at the USDA’s Eastern Regional Research Center is focused on developing this technology into an effective tool to improve the safety of a variety of foods. Cold plasma applied to outbreak strains of Escherichia coli O157:H7 and Salmonella Stanley inoculated on the ...

  10. Cold Stress and the Cold Pressor Test

    ERIC Educational Resources Information Center

    Silverthorn, Dee U.; Michael, Joel

    2013-01-01

    Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This…

  11. Cold knife cone biopsy

    MedlinePlus

    A cold knife cone biopsy (conization) is surgery to remove a sample of abnormal tissue from the cervix. The ... Cold knife cone biopsy is done to detect cervical cancer or early changes that lead to cancer. ...

  12. Cold wave lotion poisoning

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002693.htm Cold wave lotion poisoning To use the sharing features on this page, please enable JavaScript. Cold wave lotion is a hair care product used ...

  13. Cold knife cone biopsy

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003910.htm Cold knife cone biopsy To use the sharing features on this page, please enable JavaScript. A cold knife cone biopsy (conization) is surgery to remove ...

  14. Cold Sores (Orofacial Herpes)

    MedlinePlus

    ... rash and rashes clinical tools newsletter | contact Share | Cold Sores (Orofacial Herpes) Information for adults A A ... face, known as orofacial herpes simplex, herpes labialis, cold sores, or fever blisters, is a common, recurrent ...

  15. Cold and Cough Medicines

    MedlinePlus

    ... What can you do for your cold or cough symptoms? Besides drinking lots of fluids and getting ... medicines. There are lots of different cold and cough medicines, and they do different things. Nasal decongestants - ...

  16. Cold and Cough Medicines

    MedlinePlus

    ... What can you do for your cold or cough symptoms? Besides drinking plenty of fluids and getting ... medicines. There are lots of different cold and cough medicines, and they do different things. Nasal decongestants - ...

  17. Exercising in Cold Weather

    MedlinePlus

    ... www.nia.nih.gov/Go4Life Exercising in Cold Weather Exercise has benefits all year, even during winter. ... activities when it’s cold outside: l Check the weather forecast. If it’s very windy or cold, exercise ...

  18. Cold Fronts in Cold Dark Matter Clusters

    NASA Astrophysics Data System (ADS)

    Nagai, Daisuke; Kravtsov, Andrey V.

    2003-04-01

    Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters. These features, called cold fronts, are characterized by an increase in surface brightness by a factor >~2 over 10-50 kpc accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM) if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging subcluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the amplitude of gas density and temperature gradients across the front. Our results indicate that cold fronts are nonequilibrium transient phenomena and can be observed for a period of less than a billion years. We show that the velocity and density fields of gas surrounding the cold front can be very irregular, which would complicate analyses aiming to put constraints on the physical conditions of the ICM in the vicinity of the front.

  19. Cough and Cold Medicine Abuse

    MedlinePlus

    ... and Cold Medicine Abuse DrugFacts: Cough and Cold Medicine Abuse Email Facebook Twitter Revised May 2014 Some ... diverted for abuse. How Are Cough and Cold Medicines Abused? Cough and cold medicines are usually consumed ...

  20. Why Being Cold Might Foster a Cold

    MedlinePlus

    ... These cells produce essential immune system proteins called interferons that respond to a cold virus. The cells ... several degrees below core body temperature, virus-fighting interferons were less able to do their job. The ...

  1. A cAMP-independent carbohydrate-driven mechanism inhibits tnaA expression and TnaA enzyme activity in Escherichia coli.

    PubMed

    Li, Gang; Young, Kevin D

    2014-09-01

    When Escherichia coli is grown in a medium lacking glucose or another preferred carbohydrate, the concentration of cAMP-cAMP receptor protein (cAMP-CRP) increases, and this latter complex regulates the expression of more than 180 genes. To respond rapidly to changes in carbohydrate availability, E. coli must maintain a suitable intracellular concentration of cAMP by either exporting or degrading excess cAMP. Currently, cAMP export via the TolC protein is thought to be more efficient at reducing these levels than is CpdA-mediated degradation of cAMP. Here, we compared the contributions of TolC and CpdA by measuring the expression of cAMP-regulated genes that encode tryptophanase (TnaA) and β-galactosidase. In the presence of exogenous cAMP, a tolC mutant produced intermediate levels of these enzymes, suggesting that cAMP levels were held in check by CpdA. Conversely, a cpdA mutant produced much higher amounts of these enzymes, indicating that CpdA was more efficient than TolC at reducing cAMP levels. Surprisingly, expression of the tnaA gene halted rapidly when glucose was added to cells lacking both TolC and CpdA, even though under these conditions cAMP could not be removed by either pathway and tnaA expression should have remained high. This result suggests the existence of an additional mechanism that eliminates intracellular cAMP or terminates expression of some cAMP-CRP-regulated genes. In addition, adding glucose and other carbohydrates rapidly inhibited the function of pre-formed TnaA, indicating that TnaA is regulated by a previously unknown carbohydrate-dependent post-translational mechanism. PMID:25061041

  2. Regulation of the Escherichia coli tna operon: nascent leader peptide control at the tnaC stop codon.

    PubMed Central

    Konan, K V; Yanofsky, C

    1997-01-01

    Expression of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and by tryptophan-induced transcription antitermination at Rho-dependent termination sites in the leader region of the operon. Tryptophan induction is dependent on translation of a short leader peptide coding region, tnaC, that contains a single, crucial tryptophan codon. Recent studies suggest that during induction, the TnaC leader peptide acts in cis on the translating ribosome to inhibit its release at the tnaC stop codon. In the present study we use a tnaC-UGA-'lacZ construct lacking the tnaC-tnaA spacer region to analyze the effect of TnaC synthesis on the behavior of the ribosome that translates tnaC. The tnaC-UGA-'lacZ construct is not expressed significantly in the presence or absence of inducer. However, it is expressed in the presence of UGA suppressors, or when the structural gene for polypeptide release factor 3 is disrupted, or when wild-type tRNATrP is overproduced. In each situation, tnaC-UGA-'lacZ expression is reduced appreciably by the presence of inducing levels of tryptophan. Replacing the tnaC UGA stop codon with a sense codon allows considerable expression, which is also reduced, although to a lesser extent, by the addition of tryptophan. Inhibition by tryptophan is not observed when Trp codon 12 of tnaC is changed to a Leu codon. Overexpression of tnaC in trans from a multicopy plasmid prevents inhibition of expression by tryptophan. These results support the hypothesis that the TnaC leader peptide acts in cis to alter the behavior of the translating ribosome. PMID:9045840

  3. How cold is cold dark matter?

    SciTech Connect

    Armendariz-Picon, Cristian; Neelakanta, Jayanth T. E-mail: jtneelak@syr.edu

    2014-03-01

    If cold dark matter consists of particles, these must be non-interacting and non-relativistic by definition. In most cold dark matter models however, dark matter particles inherit a non-vanishing velocity dispersion from interactions in the early universe, a velocity that redshifts with cosmic expansion but certainly remains non-zero. In this article, we place model-independent constraints on the dark matter temperature to mass ratio, whose square root determines the dark matter velocity dispersion. We only assume that dark matter particles decoupled kinetically while non-relativistic, when galactic scales had not entered the horizon yet, and that their momentum distribution has been Maxwellian since that time. Under these assumptions, using cosmic microwave background and matter power spectrum observations, we place upper limits on the temperature to mass ratio of cold dark matter today (away from collapsed structures). These limits imply that the present cold dark matter velocity dispersion has to be smaller than 54 m/s. Cold dark matter has to be quite cold, indeed.

  4. Pathogenic Escherichia coli.

    PubMed

    Kaper, James B; Nataro, James P; Mobley, Harry L

    2004-02-01

    Few microorganisms are as versatile as Escherichia coli. An important member of the normal intestinal microflora of humans and other mammals, E. coli has also been widely exploited as a cloning host in recombinant DNA technology. But E. coli is more than just a laboratory workhorse or harmless intestinal inhabitant; it can also be a highly versatile, and frequently deadly, pathogen. Several different E. coli strains cause diverse intestinal and extraintestinal diseases by means of virulence factors that affect a wide range of cellular processes. PMID:15040260

  5. Human responses to cold.

    PubMed

    Rintamäki, Hannu

    2007-01-01

    The thermoneutral ambient temperature for naked and resting humans is ca. 27 degrees C. Exposure to cold stimulates cold receptors of the skin which causes cold thermal sensations and stimulation of the sympathetic nervous system. Sympathetic stimulation causes vasoconstriction in skin, arms and legs. Diminished skin and extremity blood flow increases the thermal insulation of superficial tissues more than 300% corresponding to 0.9 clo (0.13 degrees C x m(-2) x W(-1)). With thermoregulatory vasoconstriction/ vasodilatation the body heat balance can be maintained within a range of ca. 4 degrees C, the middle of the range being at ca. 21 degrees C when light clothing is used. Below the thermoneutral zone metabolic heat production (shivering) is stimulated and above the zone starts heat loss by evaporation (sweating). Cold induced vasoconstriction increases blood pressure and viscosity and decreases plasma volume consequently increasing cardiac work. Cold induced hypertensive response can be counteracted by light exercise, while starting heavy work in cold markedly increases blood pressure. Under very cold conditions the sympathetic stimulation opens the anastomoses between arterioles and venules which increases skin temperatures markedly but temporarily, especially in finger tips. Adaptation to cold takes ca. 2 weeks, whereafter the physiological responses to cold are attenuated and cold exposure is subjectively considered less stressful. PMID:17929604

  6. Arabidopsis COLD SHOCK DOMAIN PROTEIN2 is a RNA chaperone that is regulated by cold and developmental signals

    SciTech Connect

    Sasaki, Kentaro; Kim, Myung-Hee; Imai, Ryozo

    2007-12-21

    Bacterial cold shock proteins (CSPs) are RNA chaperones that unwind RNA secondary structures. Arabidopsis COLD SHOCK DOMAIN PROTEIN2 (AtCSP2) contains a domain that is shared with bacterial CSPs. Here we showed that AtCSP2 binds to RNA and unwinds nucleic acid duplex. Heterologous expression of AtCSP2 complemented cold sensitivity of an Escherichia coli csp quadruple mutant, indicating that AtCSP2 function as a RNA chaperone in E. coli. AtCSP2 mRNA and protein levels increased during cold acclimation, but the protein accumulation was most prominent after 10 days of cold treatment. AtCSP2 promoter::GUS transgenic plants revealed that AtCSP2 is expressed only in root and shoot apical regions during vegetative growth but is expressed in reproductive organs such as pollens, ovules and embryos. These data indicated that AtCSP2 is involved in developmental processes as well as cold adaptation. Localization of AtCSP2::GFP in nucleolus and cytoplasm suggested different nuclear and cytosolic RNA targets.

  7. Cold pool dissipation

    NASA Astrophysics Data System (ADS)

    Grant, Leah D.; Heever, Susan C.

    2016-02-01

    The mechanisms by which sensible heat fluxes (SHFs) alter cold pool characteristics and dissipation rates are investigated in this study using idealized two-dimensional numerical simulations and an environment representative of daytime, dry, continental conditions. Simulations are performed with no SHFs, SHFs calculated using a bulk formula, and constant SHFs for model resolutions with horizontal (vertical) grid spacings ranging from 50 m (25 m) to 400 m (200 m). In the highest resolution simulations, turbulent entrainment of environmental air into the cold pool is an important mechanism for dissipation in the absence of SHFs. Including SHFs enhances cold pool dissipation rates, but the processes responsible for the enhanced dissipation differ depending on the SHF formulation. The bulk SHFs increase the near-surface cold pool temperatures, but their effects on the overall cold pool characteristics are small, while the constant SHFs influence the near-surface environmental stability and the turbulent entrainment rates into the cold pool. The changes to the entrainment rates are found to be the most significant of the SHF effects on cold pool dissipation. SHFs may also influence the timing of cold pool-induced convective initiation by altering the environmental stability and the cold pool intensity. As the model resolution is coarsened, cold pool dissipation is found to be less sensitive to SHFs. Furthermore, the coarser resolution simulations not only poorly but sometimes wrongly represent the SHF impacts on the cold pools. Recommendations are made regarding simulating the interaction of cold pools with convection and the land surface in cloud-resolving models.

  8. Cold fusion, Alchemist's dream

    SciTech Connect

    Clayton, E.D.

    1989-09-01

    In this report the following topics relating to cold fusion are discussed: muon catalysed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalysed cold fusion; vibrational mechanisms in excited states of D{sub 2} molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D{sub 2} fusion at low energies; fusion of deuterons into {sup 4}He; secondary D+T fusion within the hydrogenated metal lattice; {sup 3}He to {sup 4}He ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of {sup 3}He/{sup 4}He.

  9. Pathogenic Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli, a member of the Enterobacteriaceae family, is a part of the normal flora of the intestinal tract of humans and a variety of animals. E. coli strains are classified on the basis of antigenic differences in two surface components (serotyping), the somatic antigen (O) of the lipopoly...

  10. PATHOGENIC ESCHERICHIA COLI

    EPA Science Inventory

    Escherichia coli is a bacterial species which inhabits the gastrointestinal tract of man and warm-blooded animals. Because of the ubiquity of this bacterium in the intestinal flora, it serves as an important indicator organism of fecal contamination. E. coli, aside from serving a...

  11. Cold stress and the cold pressor test.

    PubMed

    Silverthorn, Dee U; Michael, Joel

    2013-03-01

    Temperature and other environmental stressors are known to affect blood pressure and heart rate. In this activity, students perform the cold pressor test, demonstrating increased blood pressure during a 1- to 2-min immersion of one hand in ice water. The cold pressor test is used clinically to evaluate autonomic and left ventricular function. This activity is easily adapted to an inquiry format that asks students to go to the scientific literature to learn about the test and then design a protocol for carrying out the test in classmates. The data collected are ideal for teaching graphical presentation of data and statistical analysis. PMID:23471256

  12. Cold shock and cold acclimation proteins in the psychrotrophic bacterium Arthrobacter globiformis SI55.

    PubMed Central

    Berger, F; Morellet, N; Menu, F; Potier, P

    1996-01-01

    The psychrotrophic bacterium Arthrobacter globiformis SI55 was grown at 4 and 25 degrees C, and the cell protein contents were analyzed by two-dimensional electrophoresis. Cells subjected to cold shocks of increasing magnitude were also analyzed. Correspondence analysis of protein appearance distinguished four groups of physiological significance. Group I contained cold shock proteins (Csps) overexpressed only after a large temperature downshift. Group II contained Csps with optimal expression after mild shocks. Group III contained proteins overexpressed after all cold shocks. These last proteins were also overexpressed in cells growing at 4 degrees C and were considered to be early cold acclimation proteins (Caps). Group IV contained proteins which were present at high concentrations only in 4 degrees C steady-state cells and appeared to be late Caps. A portion of a gene very similar to the Escherichia coli cspA gene (encoding protein CS7.4) was identified. A synthetic peptide was used to produce an antibody which detected a CS7.4-like protein (A9) by immunoblotting two-dimensional electrophoresis gels of A. globiformis SI55 total proteins. Unlike mesophilic microorganisms, this CS7.4-like protein was still produced during prolonged growth at low temperature, and it might have a particular adaptive function needed for balanced growth under harsh conditions. However, A9 was induced at high temperature by chloramphenicol, suggesting that CS7.4-like proteins have a more general role than their sole implication in cold acclimation processes. PMID:8655472

  13. Cold Sores (HSV-1)

    MedlinePlus

    ... Help a Friend Who Cuts? Cold Sores (HSV-1) KidsHealth > For Teens > Cold Sores (HSV-1) Print A A A Text Size What's in ... person's lips, are caused by herpes simplex virus-1 (HSV-1) . But they don't just show ...

  14. Liquid metal cold trap

    DOEpatents

    Hundal, Rolv

    1976-01-01

    A cold trap assembly for removing impurities from a liquid metal being provided with a hole between the incoming impure liquid metal and purified outgoing liquid metal which acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly.

  15. Primary cold agglutinin disease.

    PubMed

    Mondal, Prabodh Chandra; Chakraborty, Partha Pratim; Bera, Mitali

    2011-07-01

    A 4-year-old girl presented with severe pallor and intermittent passage of cola-coloured urine. Routine investigations were suggestive of auto-immune haemolytic anaemia. Red cell agglutination was observed in peripheral smear and patient's serum was positive for cold agglutinins. Thorough work-up ruled out secondary cold agglutinin disease. Patient was treated successfully with corticosteroids. PMID:22315851

  16. Cold fusion research

    SciTech Connect

    1989-11-01

    I am pleased to forward to you the Final Report of the Cold Fusion Panel. This report reviews the current status of cold fusion and includes major chapters on Calorimetry and Excess Heat, Fusion Products and Materials Characterization. In addition, the report makes a number of conclusions and recommendations, as requested by the Secretary of Energy.

  17. Hypothermia: A Cold Weather Hazard

    MedlinePlus

    ... Weather Hazard Heath and Aging Hypothermia: A Cold Weather Hazard What Are The Signs Of Hypothermia? Taking ... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ...

  18. E. Coli Infections

    MedlinePlus

    ... You can also get the infection by swallowing water in a swimming pool contaminated with human waste. Most cases of E. coli infection get better without treatment in 5 to 10 days. NIH: National Institute ...

  19. [Enterohemorrhagic E. coli (EHEC)].

    PubMed

    Goto, Tetsushi; Shirano, Michinori

    2012-08-01

    Escherichia coli (E. coli) is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless. Some strains however, such as enterohemorrhagic E. coli (EHEC), can cause severe foodborne disease. It is transmitted to humans primarily through consumption of contaminated foods, such as raw meal. EHEC produces toxins, known as verotoxins. EHEC that induces bloody diarrhea leads to HUS in 10% of cases. The clinical manifestations of post-diarrheal HUS include acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia. The verocytotoxin can directly damage renal and endothelial cells. Thrombocytopenia occurs as platelets are consumed by clotting. Hemolytic anemia results from intravascular fibrin deposition, increased fragility of red blood cells, and fragmentation. PMID:22894069

  20. Recurrent Escherichia coli bacteremia.

    PubMed Central

    Maslow, J N; Mulligan, M E; Arbeit, R D

    1994-01-01

    Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-field gel electrophoresis (PFGE) and ribotyping and for the presence of E. coli virulence factors. For each of four patients, the index and recurrent episodes of bacteremia represented the same strain as defined by PFGE, and the strains were found to carry one or more virulence factors. The remaining patient, with two episodes of bloodstream infection separated by a 4-year interval, was infected with two isolates that did not carry any virulence factors and that were clonally related by ribotype analysis but differed by PFGE. All five patients had either a local host defense defect (three patients) or impaired systemic defenses (one patient) or both (one patient). Thus, recurrent E. coli bacteremia is likely to represent a multifactorial process that occurs in patients with impaired host defenses who are infected with virulent isolates. Images PMID:7910828

  1. Febrile/cold agglutinins

    MedlinePlus

    ... diagnose certain infections and find the cause of hemolytic anemia (a type of anemia that occurs when red ... or cold agglutinins can help explain why the hemolytic anemia is occurring and direct treatment.

  2. Antimicrobial effects of three tropical plant extracts on Staphylococcus aureus, Escherichia coli and Candida albicans.

    PubMed

    Okigbo, R N; Mmeka, E C

    2008-01-01

    Antimicrobial activities of the leaf extracts of Cymbopogon citatrus (lemongrass) and Vernonia amygdalina (bitter leaf) and the seed extracts of Garcinia kola (bitter kola) were carried out. G. kola had effect only on Staphylococcus aureus and Escherichia coli with no inhibition on Candida albicans. Ethanol, cold water and hot water extracts of Vernonia amygdalina and Cymbopogon citratus showed inhibition on the three organism but G. kola ethanol, cold water and hot water extracts only inhibited S. aureus and E. coli with no inhibition on Candida albicans. The organism's susceptibility varied with more inhibition to S. aureus and least to Candida albicans. PMID:20161941

  3. Teaching in a Cold Environment.

    ERIC Educational Resources Information Center

    Ewert, Alan

    1979-01-01

    Designed to help teachers deal with students in a cold environment, this article explains cold physiology and fundamental laws of heat; describes 14 common cold injuries and their current treatment; and lists a number of useful teaching techniques for cold environments. (SB)

  4. Teaching in a Cold Environment.

    ERIC Educational Resources Information Center

    Ewert, Alan

    Instructors who teach outdoors in an environment so cold as to cause injury must satisfy program objectives while avoiding cold injury to themselves and students, help students focus on learning instead of discomfort, and alleviate some students' intense fear of the cold. Dealing with the cold successfully requires a thorough knowledge of:…

  5. Cold moderators at ORNL

    SciTech Connect

    Lucas, A. T.

    1997-09-01

    The Advanced Neutron Source (ANS) cold moderators were not an 'Oak Ridge first', but would have been the largest both physically and in terms of cold neutron flux. Two cold moderators were planned each 410 mm in diameter and containing about 30L of liquid deuterium. They were to be completely independent of each other. A modular system design was used to provide greater reliability and serviceability. When the ANS was terminated, up–grading of the resident High Flux Isotope Reactor (HFIR) was examined and an initial study was made into the feasibility of adding a cold source. Because the ANS design was modular, it was possible to use many identical design features. Sub-cooled liquid at 4 bar abs was initially chosen for the HFIR design concept, but this was subsequently changed to 15 bar abs to operate above the critical pressure. As in the ANS, the hydrogen will operate at a constant pressure throughout the temperature range and a completely closed loop with secondary containment was adopted. The heat load of 2 kW made the heat flux comparable with that of the ANS. Subsequent studies into the construction of cryogenic moderators for the proposed new Synchrotron Neutron source indicated that again many of the same design concepts could be used. By connecting the two cold sources together in series, the total heat load of 2 kW is very close to that of the HFIR allowing a very similar supercritical hydrogen system to be configured. The two hydrogen moderators of the SNS provide a comparable heat load to the HFIR moderator. It is subsequently planned to connect the two in series and operate from a single cold loop system, once again using supercritical hydrogen. The spallation source also provided an opportunity to re-examine a cold pellet solid methane moderator operating at 20K.

  6. "Cold training" affects rat liver responses to continuous cold exposure.

    PubMed

    Venditti, Paola; Napolitano, Gaetana; Barone, Daniela; Di Meo, Sergio

    2016-04-01

    Continuous exposure of homeothermic animals to low environmental temperatures elicits physiological adaptations necessary for animal survival, which are associated to higher generation of pro-oxidants in thermogenic tissues. It is not known whether intermittent cold exposure (cold training) is able to affect tissue responses to continuous cold exposure. Therefore, we investigated whether rat liver responses to continuous cold exposure of 2 days are modified by cold training (1h daily for 5 days per week for 3 consecutive weeks). Continuous cold increased liver oxidative metabolism by increasing tissue content of mitochondrial proteins and mitochondrial aerobic capacity. Cold training did not affect such parameters, but attenuated or prevented the changes elicited by continuous cold exposure. Two-day cold exposure increased lipid hydroperoxide and protein-bound carbonyl levels in homogenates and mitochondria, whereas cold training decreased such effects although it decreased only homogenate protein damage in control rats. The activities of the antioxidant enzymes GPX and GR and H2O2 production were increased by continuous cold exposure. Despite the increase in GPX and GR activities, livers from cold-exposed rats showed increased susceptibility to in vitro oxidative challenge. Such cold effects were decreased by cold training, which in control rats reduced only H2O2 production and susceptibility to stress. The changes of PGC-1, NRF-1, and NRF-2 expression levels were consistent with those induced by cold exposure and cold training in mitochondrial protein content and antioxidant enzyme activities. However, the mechanisms by which cold training attenuates the effects of the continuous cold exposure remain to be elucidated. PMID:26808664

  7. Massive cold cloud clusters

    NASA Astrophysics Data System (ADS)

    Toth, L. Viktor; Marton, Gabor; Zahorecz, Sarolta

    2015-08-01

    The all-sky Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015) allows an almost unbiased study of the early phases of star-formation in our Galaxy. Several thousand of the clumps have also distance estimates allowing a mass, and density determination. The nature of Planck clumps varies from IRDCs to tiny nearby cold clouds with masses ranging from one to several tens of thousands solar masses. Some of the clumps are embedded in GMCs, others are isolated. Some are close or even very close to OB associations, while others lay far from any UV luminous objects.The small scale clustering of these objects was studied with the improved Minimum Spanning Tree method of Cartwright & Whitworth identifying groups in 3D space. As a result also massive cold cloud clusters were identified. We analyse the MST structures, and discuss their relation to ongoing and future massive star formation.

  8. Cold-responsive gene regulation during cold acclimation in plants.

    PubMed

    Lissarre, Mickael; Ohta, Masaru; Sato, Aiko; Miura, Kenji

    2010-08-01

    Regulation of the transcriptome is necessary for plants to acquire cold tolerance, and cold induces several genes via a cold signaling pathway. The transcription factors CBF/DREB1 (C-repeat binding factor/dehydration responsive element binding1) and ICE1 (inducer of CBF expression1) have important roles in the regulation of cold-responsive gene expression. ICE1 is post-translationally regulated by ubiquitylation-mediated proteolysis and sumoylation. This mini-review highlights some recent studies on plant cold signaling. The relationships among cold signaling, salicylic acid accumulation and stomatal development are also discussed. PMID:20699657

  9. Genetic recombination. [Escherichia coli

    SciTech Connect

    Stahl, F.W.

    1987-02-01

    The molecular pathways of gene recombination are explored and compared in studies of the model organisms, Escherichia coli and phase lambda. In the discussion of data from these studies it seems that recombination varies with the genetic idiosyncrasies of the organism and may also vary within a single organism.

  10. Role of Ribosome Release in Regulation of tna Operon Expression in Escherichia coli

    PubMed Central

    Konan, Kouacou Vincent; Yanofsky, Charles

    1999-01-01

    Expression of the degradative tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. In cultures growing in the absence of added tryptophan, transcription of the structural genes of the tna operon is limited by Rho-dependent transcription termination in the leader region of the operon. Tryptophan induction prevents this Rho-dependent termination, and requires in-frame translation of a 24-residue leader peptide coding region, tnaC, that contains a single, crucial, Trp codon. Studies with a lacZ reporter construct lacking the spacer region between tnaC and the first major structural gene, tnaA, suggested that tryptophan induction might involve cis action by the TnaC leader peptide on the ribosome translating the tnaC coding region. The leader peptide was hypothesized to inhibit ribosome release at the tnaC stop codon, thereby blocking Rho’s access to the transcript. Regulatory studies with deletion constructs of the tna operon of Proteus vulgaris supported this interpretation. In the present study the putative role of the tnaC stop codon in tna operon regulation in E. coli was examined further by replacing the natural tnaC stop codon, UGA, with UAG or UAA in a tnaC-stop codon-tnaA′-′lacZ reporter construct. Basal level expression was reduced to 20 and 50% when the UGA stop codon was replaced by UAG or UAA, respectively, consistent with the finding that in E. coli translation terminates more efficiently at UAG and UAA than at UGA. Tryptophan induction was observed in strains with any of the stop codons. However, when UAG or UAA replaced UGA, the induced level of expression was also reduced to 15 and 50% of that obtained with UGA as the tnaC stop codon, respectively. Introduction of a mutant allele encoding a temperature-sensitive release factor 1, prfA1, increased basal level expression 60-fold when the tnaC stop codon was UAG and 3-fold when this stop codon was UAA; basal level

  11. Cold War Propaganda.

    ERIC Educational Resources Information Center

    Bennett, Paul W.

    1988-01-01

    Briefly discusses the development of Cold War propaganda in the United States, Canada, and the USSR after 1947. Presents two movie reviews and a Canadian magazine advertisement of the period which illustrate the harshness of propaganda used by both sides in the immediate postwar years. (GEA)

  12. Cold Facts about Viruses.

    ERIC Educational Resources Information Center

    Pea, Celeste; Sterling, Donna R.

    2002-01-01

    Provides ways for students to demonstrate their understanding of scientific concepts and skills. Describes a mini-unit around the cold in which students can relate humans to viruses. Includes activities and a modified simulation that provides questions to guide students. Discusses ways that allows students to apply prior knowledge, take ownership…

  13. Breeding Cold Hardy Begonias

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hardy begonia cultivars have potential as a new crop for Southern nurseries. Current begonia breeding efforts are focused on sections Begonia and Pritzelia. Diverse begonia germplasm has been collected to study fertility and hardiness.To date cold hardy germplasm which has produced viable seeds inc...

  14. Recent Cold War Studies

    ERIC Educational Resources Information Center

    Pineo, Ronn

    2003-01-01

    Cold War historiography has undergone major changes since the 1991 collapse of the Soviet Union. For two years (1992-1993) the principal Soviet archives fell open to scholars, and although some of the richest holdings are now once again closed, new information continues to find its way out. Moreover, critical documentary information has become…

  15. Teaching "In Cold Blood."

    ERIC Educational Resources Information Center

    Berbrich, Joan D.

    1967-01-01

    The Truman Capote nonfiction novel, "In Cold Blood," which reflects for adolescents the immediacy of the real world, illuminates (1) social issues--capital punishment, environmental influence, and the gap between the "haves" and "have-nots," (2) moral issues--the complexity of man's nature, the responsibility of one man for another, and the place…

  16. Titanium Cold Spray Coatings

    NASA Astrophysics Data System (ADS)

    Ajaja, Jihane; Goldbaum, Dina; Chromik, Richard; Yue, Stephen; Rezaeian, Ahmad; Wong, Wilson; Irissou, Eric; Legoux, Jean-Gabriel

    Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical properties similar to a traditional bulk material. Vickers hardness testing and nanoindentation were used as micro-and nano-scale measurement techniques to characterize the mechanical properties of titanium coatings, deposited at different deposition conditions, and bulk Ti. The mechanical properties of bulk titanium and titanium coatings were measured over a range of length scales, with the indentation size effect examined with Meyer's law. Hardness measurements are shown to be affected by material porosity, microstructure and coating particle bonding mechanism. Hard-ness measurements showed that Ti coatings deposited at higher gas pressures and temperatures demonstrate an indentation load response similar to bulk Ti. Key words: titanium, cold spray, Vickers hardness, nanoindentation, indentation size effect, microstructure, mechanical properties

  17. Diffraction by cold atoms

    NASA Astrophysics Data System (ADS)

    Strauch, F.; Gomer, V.; Schadwinkel, H.; Ueberholz, B.; Haubrich, D.; Meschede, D.

    1998-01-01

    We have observed diffraction of a laser probe beam by a trapped sample of cold atoms. The effect is only visible in the vicinity of a resonance line. The observed diffraction pattern arises from interference of the incident and scattered light wave, allowing reconstruction of geometric properties of the trapped sample from the holographic record.

  18. Heating up cold agglutinins.

    PubMed

    Stone, Marvin J

    2010-10-28

    In this issue of Blood, Berentsen and coworkers describe a high response rate which is durable in some patients who receive combination fludarabine and rituximab for chronic cold agglutinin disease (CAD). If confirmed, this is a significant advance in therapy for a frequently difficult clinical problem. PMID:21030565

  19. Cold agglutinin disease.

    PubMed

    Swiecicki, Paul L; Hegerova, Livia T; Gertz, Morie A

    2013-08-15

    Cold agglutinin disease is a rare and poorly understood disorder affecting 15% of patients with autoimmune hemolytic anemia. We reviewed the clinical and pathologic features, prognosis, and management in the literature and describe our institutional experience to improve strategies for accurate diagnosis and treatment. Retrospective analysis identified 89 patients from our institution with cold agglutinin disease from 1970 through 2012. Median age at symptom onset was 65 years (range, 41 to 83 years), whereas the median age at diagnosis was 72 years (range, 43 to 91 years). Median survival of all patients was 10.6 years, and 68 patients (76%) were alive 5 years after the diagnosis. The most common symptom was acrocyanosis (n = 39 [44%]), and many had symptoms triggered by cold (n = 35 [39%]) or other factors (n = 20 [22%]). An underlying hematologic disorder was detected in 69 patients (78%). Thirty-six patients (40%) received transfusions during their disease course, and 82% received drug therapy. Rituximab was associated with the longest response duration (median, 24 months) and the lowest proportion of patients needing further treatment (55%). Our institution's experience and review of the literature confirms that early diagnostic evaluation and treatment improves outcomes in cold agglutinin disease. PMID:23757733

  20. Out in the cold.

    PubMed

    Bates, Jane

    2016-05-01

    Every now and then, you say something to a patient and wonder whether you should have kept quiet. On this occasion, a female patient and I were indulging in a moment of shared empathy over an annoying symptom we both experience - permanently cold feet. PMID:27154099

  1. Cold spray nozzle design

    DOEpatents

    Haynes, Jeffrey D.; Sanders, Stuart A.

    2009-06-09

    A nozzle for use in a cold spray technique is described. The nozzle has a passageway for spraying a powder material, the passageway having a converging section and a diverging section, and at least the diverging section being formed from polybenzimidazole. In one embodiment of the nozzle, the converging section is also formed from polybenzimidazole.

  2. Expert Cold Structure Development

    NASA Astrophysics Data System (ADS)

    Atkins, T.; Demuysere, P.

    2011-05-01

    The EXPERT Program is funded by ESA. The objective of the EXPERT mission is to perform a sub-orbital flight during which measurements of critical aero- thermodynamic phenomena will be obtained by using state-of-the-art instrumentation. As part of the EXPERT Flight Segment, the responsibility of the Cold Structure Development Design, Manufacturing and Validation was committed to the Belgian industrial team SONACA/SABCA. The EXPERT Cold Structure includes the Launcher Adapter, the Bottom Panel, the Upper Panel, two Cross Panels and the Parachute Bay. An additional Launcher Adapter was manufactured for the separation tests. The selected assembly definition and manufacturing technologies ( machined parts and sandwich panels) were dictated classically by the mass and stiffness, but also by the CoG location and the sensitive separation interface. Used as support for the various on-board equipment, the Cold Structure is fixed to but thermally uncoupled from the PM 1000 thermal shield. It is protect on its bottom panel by a thermal blanket. As it is a protoflight, analysis was the main tool for the verification. Low level stiffness and modal analysis tests have also been performed on the Cold Structure equipped with its ballast. It allowed to complete its qualification and to prepare SONACA/SABCA support for the system dynamic tests foreseen in 2011. The structure was finally coated with a thermal control black painting and delivered on time to Thales Alenia Space-Italy end of March 201.

  3. Cold plasma - a non-thermal processing technology to inactivate human pathogens on foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma is a novel non-thermal food processing technology, suitable for application to fresh and fresh-cut fruits and vegetables. Reductions of 3-5 logs have been achieved against human pathogens such as Salmonella and E. coli O157:H7 on fresh produce and against phytopathogens and spoilage orga...

  4. Thermoregulatory modeling for cold stress.

    PubMed

    Xu, Xiaojiang; Tikuisis, Peter

    2014-07-01

    Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview. PMID:24944030

  5. Prescription Drugs and Cold Medicines

    MedlinePlus

    ... Abuse » Prescription Drugs & Cold Medicines Prescription Drugs & Cold Medicines Email Facebook Twitter What is Prescription Drug Abuse: ... treatment of addiction. Read more Safe Disposal of Medicines Disposal of Unused Medicines: What You Should Know ( ...

  6. Imaging with cold neutrons

    NASA Astrophysics Data System (ADS)

    Lehmann, E. H.; Kaestner, A.; Josic, L.; Hartmann, S.; Mannes, D.

    2011-09-01

    Neutrons for imaging purposes are provided mainly from thermal beam lines at suitable facilities around the world. The access to cold neutrons is presently limited to very few places only. However, many challenging options for imaging with cold neutrons have been found out, given by the interaction behavior of the observed materials with neutrons in the cold energy range (3-10 Å). For absorbing materials, the interaction probability increases proportionally with the wavelength with the consequence of more contrast but less transmission with cold neutrons. Many materials are predominantly scattering neutrons, in particular most of crystalline structural materials. In these cases, cold neutrons play an important role by covering the energy range of the most important Bragg edges given by the lattice planes of the crystallites. This particular behavior can be used for at least two important aspects—choosing the right energy of the initial beam enables to have a material more or less transparent, and a direct macroscopic visualization of the crystalline structure and its change in a manufacturing process. Since 2006, PSI operates its second beam line for neutron imaging, where cold neutrons are provided from a liquid deuterium cold source (operated at 25 K). It has been designed to cover the most current aspects in neutron imaging research with the help of high flexibility. This has been done with changeable inlet apertures, a turbine based velocity selector, two beam positions and variable detector systems, satisfying the demands of the individual investigation. The most important detection system was found to be a micro-tomography system that enables studies in the presently best spatial resolution. In this case, the high contrast from the sample interaction process and the high detection probability for the cold neutrons combines in an ideal combination for the best possible performance. Recently, it was found out that the energy selective studies might become a

  7. Unwinding activity of cold shock proteins and RNA metabolism.

    PubMed

    Phadtare, Sangita

    2011-01-01

    Temperature downshift from 37 °C to 15 °C results in the exertion of cold shock response in Escherichia coli, which induces cold shock proteins, such as CsdA. Previously, we showed that the helicase activity of CsdA is critical for its function in the cold acclimation of cells and its primary role is mRNA degradation. Only RhlE (helicase), CspA (RNA chaperone) and RNase R (exoribonuclease) were found to complement the cold shock function of CsdA. RNase R has two independent activities, helicase and ribonuclease, only helicase being essential for the functional complementation of CsdA. Here, we discuss the significance of above findings as these emphasize the importance of the unwinding activity of cold-shock-inducible proteins in the RNA metabolism at low temperature, which may be different than that at 37 °C. It requires assistance of proteins to destabilize the secondary structures in mRNAs that are stabilized upon temperature downshift, hindering the activity of ribonucleases. PMID:21445001

  8. Human whole body cold adaptation.

    PubMed

    Daanen, Hein A M; Van Marken Lichtenbelt, Wouter D

    2016-01-01

    Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold. PMID:27227100

  9. Human whole body cold adaptation

    PubMed Central

    Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

    2016-01-01

    ABSTRACT Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold. PMID:27227100

  10. Health problems in cold work.

    PubMed

    Mäkinen, Tiina M; Hassi, Juhani

    2009-07-01

    Cold in- and outdoor work can result in different adverse effects on human health. Health problems decrease performance and work productivity and increase the occurrence of accidents and injuries. Serious health problems can also result in absence from work due to sick leave or hospitalization. At its worst, work in cold conditions could be associated with deaths due to cold-related accidents or a sudden health event. Musculoskeletal complaints, like pain, aches etc. are common in indoor cold work. Breathing cold air while working may lead to respiratory symptoms, which can decrease performance in cold. The symptoms are usually worsened by exercise and ageing, being more common in persons having a respiratory disease. Cardiovascular complaints and related performance decrements could be especially pronounced during work in cold weather and involving physical exercise, especially among those with an underlying cardiovascular disease. The article also reviews the current information related to diabetes, skin disorders and diseases, as well as cold injuries and accidents occurring in cold work. Increasing awareness and identifying workplace- and individual-related cold risks is the first step in proper cold risk management. Following this, the susceptible population groups need customized advice on proper prevention and protection in cold work. PMID:19531906

  11. Remedies for Common Cold Symptoms

    PubMed Central

    Miller, Penny F.

    1991-01-01

    Individuals suffering from intolerable symptoms of the common cold can now be advised of safe and effective products for symptomatic relief. This article describes and discusses four categories of drugs used to treat the common cold. To simplify the product selection process for family physicians, suggestions are included for possible ingredients for treatments of specific cold symptoms. PMID:21234087

  12. When blood runs cold: cold agglutinins and cardiac surgery.

    PubMed

    Findlater, Rhonda R; Schnell-Hoehn, Karen N

    2011-01-01

    Cold agglutinins are particular cold-reactive antibodies that react with red blood cells when the blood temperature drops below normal body temperature causing increased blood viscosity and red blood cell clumping. Most individuals with cold agglutinins are not aware of their presence, as these antibodies have little effect on daily living, often necessitating no treatment. However, when those with cold agglutinins are exposed to hypothermic situations or undergo procedures such as cardiopulmonary bypass with hypothermia during cardiac surgery, lethal complications of hemolysis, microvascular occlusion and organ failure can occur. By identifying those suspected of possessing cold agglutinins through a comprehensive nursing assessment and patient history, cold agglutinin screening can be performed prior to surgery to determine a diagnosis of cold agglutinin disease. With a confirmed diagnosis of cold agglutinin disease, the plan of care can be focused on measures to maintain the patient's blood temperature above the thermal amplitude throughout their hospitalization including the use of normothermic cardiopulmonary bypass with warm myocardial preservation techniques to prevent these fatal complications. Using a case report approach, the authors review the mechanism, clinical manifestations, detection and nursing management of a patient with cold agglutinins undergoing scheduled cardiac surgery. Cold agglutinin disease is rare. However, the risk to patients warrants an increased awareness of cold agglutinins and screening for those who are suspected of carrying these antibodies. PMID:21630629

  13. Radial cold trap

    DOEpatents

    Grundy, Brian R.

    1981-01-01

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

  14. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  15. Cold nuclear fusion

    SciTech Connect

    Tsyganov, E. N.

    2012-02-15

    Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.

  16. Clumpy cold dark matter

    NASA Technical Reports Server (NTRS)

    Silk, Joseph; Stebbins, Albert

    1993-01-01

    A study is conducted of cold dark matter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass dark matter cores in globular clusters and in galactic nuclei. Results from terrestrial dark matter detection experiments may be affected by clumpiness in the Galactic halo.

  17. Cold Stowage Flight Systems

    NASA Technical Reports Server (NTRS)

    Campana, Sharon E.; Melendez, David T.

    2011-01-01

    The International Space Station (ISS) provides a test bed for researchers to perform science experiments in a variety of fields, including human research, life sciences, and space medicine. Many of the experiments being conducted today require science samples to be stored and transported in a temperature controlled environment. NASA provides several systems which aid researchers in preserving their science. On orbit systems provided by NASA include the Minus Eighty Laboratory freezer for ISS (MELFI), Microgravity Experiment Research Locker Incubator (MERLIN), and Glacier. These freezers use different technologies to provide rapid cooling and cold stowage at different temperature levels on board ISS. Systems available to researchers during transportation to and from ISS are MERLIN, Glacier, and Coldbag. Coldbag is a passive cold stowage system that uses phase change materials to maintain temperature. Details of these current technologies are provided along with operational experience gained to date. This paper discusses the capability of the current cold stowage hardware and how it may continue to support NASA s mission on ISS and in future exploration missions.

  18. Cold Stowage Flight Systems

    NASA Technical Reports Server (NTRS)

    Campana, Sharon

    2010-01-01

    The International Space Station (ISS) provides a test bed for researchers to perform science experiments in a variety of fields, including human research, life sciences, and space medicine. Many of the experiments being conducted today require science samples to be stored and transported in a temperature controlled environment. NASA provides several systems which aide researchers in preserving their science. On orbit systems provided by NASA include the Minus Eighty Laboratory freezer for ISS (MELFI), Microgravity Experiment Research Locker Incubator (MERLIN), and Glacier. These freezers use different technologies to provide rapid cooling and cold stowage at different temperature levels on board ISS. Systems available to researchers during transportation to and from ISS are MERLIN, Glacier, and Coldbag. Coldbag is a passive cold stowage system that uses phase change materials. Details of these current technologies will be provided along with operational experience gained to date. With shuttle retirement looming, NASA has protected the capability to provide a temperature controlled environment during transportation to and from the ISS with the use of Glacier and Coldbags, which are compatible with future commercial vehicles including SpaceX's Dragon Capsule, and Orbital s Cygnus vehicle. This paper will discuss the capability of the current cold stowage hardware and how it may continue to support NASA s mission on ISS and in future exploration missions.

  19. New insights into Escherichia coli metabolism: carbon scavenging, acetate metabolism and carbon recycling responses during growth on glycerol

    PubMed Central

    2012-01-01

    Background Glycerol has enhanced its biotechnological importance since it is a byproduct of biodiesel synthesis. A study of Escherichia coli physiology during growth on glycerol was performed combining transcriptional-proteomic analysis as well as kinetic and stoichiometric evaluations in the strain JM101 and certain derivatives with important inactivated genes. Results Transcriptional and proteomic analysis of metabolic central genes of strain JM101 growing on glycerol, revealed important changes not only in the synthesis of MglB, LamB and MalE proteins, but also in the overexpression of carbon scavenging genes: lamB, malE, mglB, mglC, galP and glk and some members of the RpoS regulon (pfkA, pfkB, fbaA, fbaB, pgi, poxB, acs, actP and acnA). Inactivation of rpoS had an important effect on stoichiometric parameters and growth adaptation on glycerol. The observed overexpression of poxB, pta, acs genes, glyoxylate shunt genes (aceA, aceB, glcB and glcC) and actP, suggested a possible carbon flux deviation into the PoxB, Acs and glyoxylate shunt. In this scenario acetate synthesized from pyruvate with PoxB was apparently reutilized via Acs and the glyoxylate shunt enzymes. In agreement, no acetate was detected when growing on glycerol, this strain was also capable of glycerol and acetate coutilization when growing in mineral media and derivatives carrying inactivated poxB or pckA genes, accumulated acetate. Tryptophanase A (TnaA) was synthesized at high levels and indole was produced by this enzyme, in strain JM101 growing on glycerol. Additionally, in the isogenic derivative with the inactivated tnaA gene, no indole was detected and acetate and lactate were accumulated. A high efficiency aromatic compounds production capability was detected in JM101 carrying pJLBaroGfbrtktA, when growing on glycerol, as compared to glucose. Conclusions The overexpression of several carbon scavenging, acetate metabolism genes and the absence of acetate accumulation occurred in JM101

  20. The Isis cold moderators

    SciTech Connect

    Allen, G. M.; Broome, T. A.; Burridge, R. A.; Cragg, D.; Hall, R.; Haynes, D.; Hirst, J.; Hogston, J. R.; Jones, H. H.; Sexton, J.; Wright, P.

    1997-09-01

    ISIS is a pulsed spallation neutron source where neutrons are produced by the interaction of a 160 kW proton beam of energy 800 MeV in a water-cooled Tantalum Target. The fast neutrons produced are thermalized in four moderators: two ambient water, one liquid methane operating at 100K and a liquid hydrogen moderator at 20 K. This paper gives a description of the construction of both cold moderator systems, details of the operating experience and a description of the current development program.

  1. Paroxysmal cold hemoglobinuria.

    PubMed

    Shanbhag, Satish; Spivak, Jerry

    2015-06-01

    Paroxysmal cold hemoglobinuria is a rare cause of autoimmune hemolytic anemia predominantly seen as an acute form in young children after viral illnesses and in a chronic form in some hematological malignancies and tertiary syphilis. It is a complement mediated intravascular hemolytic anemia associated with a biphasic antibody against the P antigen on red cells. The antibody attaches to red cells at colder temperatures and causes red cell lysis when blood recirculates to warmer parts of the body. Treatment is mainly supportive and with red cell transfusion, but immunosuppressive therapy may be effective in severe cases. PMID:26043386

  2. Emerging Enteropathogenic Escherichia coli Strains?

    PubMed Central

    Irino, Kinue; Girão, Dennys M.; Girão, Valéria B.C.; Guth, Beatriz E.C.; Vaz, Tânia M.I.; Moreira, Fabiana C.; Chinarelli, Silvia H.; Vieira, Mônica A.M.

    2004-01-01

    Escherichia coli strains of nonenteropathogenic serogroups carrying eae but lacking the enteropathogenic E. coli adherence factor plasmid and Shiga toxin DNA probe sequences were isolated from patients (children, adults, and AIDS patients) with and without diarrhea in Brazil. Although diverse in phenotype and genotype, some strains are potentially diarrheagenic. PMID:15504277

  3. Characterization of Two Dinoflagellate Cold Shock Domain Proteins

    PubMed Central

    Beauchemin, Mathieu; Roy, Sougata; Pelletier, Sarah; Averback, Alexandra; Lanthier, Frederic

    2016-01-01

    ABSTRACT Roughly two-thirds of the proteins annotated as transcription factors in dinoflagellate transcriptomes are cold shock domain-containing proteins (CSPs), an uncommon condition in eukaryotic organisms. However, no functional analysis has ever been reported for a dinoflagellate CSP, and so it is not known if they do in fact act as transcription factors. We describe here some of the properties of two CSPs from the dinoflagellate Lingulodinium polyedrum, LpCSP1 and LpCSP2, which contain a glycine-rich C-terminal domain and an N-terminal cold shock domain phylogenetically related to those in bacteria. However, neither of the two LpCSPs act like the bacterial CSP, since they do not functionally complement the Escherichia coli quadruple cold shock domain protein mutant BX04, and cold shock does not induce LpCSP1 and LpCSP2 to detectable levels, based on two-dimensional gel electrophoresis. Both CSPs bind to RNA and single-stranded DNA in a nonspecific manner in electrophoretic mobility shift assays, and both proteins also bind double-stranded DNA nonspecifically, albeit more weakly. These CSPs are thus unlikely to act alone as sequence-specific transcription factors. IMPORTANCE Dinoflagellate transcriptomes contain cold shock domain proteins as the major component of the proteins annotated as transcription factors. We show here that the major family of cold shock domain proteins in the dinoflagellate Lingulodinium do not bind specific sequences, suggesting that transcriptional control is not a predominant mechanism for regulating gene expression in this group of protists. PMID:27303711

  4. Cold Atom Magnetometers

    NASA Astrophysics Data System (ADS)

    Eto, Yujiro; Sadrove, Mark; Hirano, Takuya

    Detection of weak magnetic fields with high spatial resolution is an important technology for various applications such as biological imaging, detection of MRI signals and fundamental physics. Cold atom magnetometry enables 10-11 T/ Hz sqrt{text{Hz}} sensitivities at the micron scale, that is, at the scale of a typical biological cell size. This magnetometry takes advantage of unique properties of atomic gaseous Bose-Einstein condensates with internal spin degrees of freedom. In this chapter, we first overview various state-of-the-art magnetometers, addressing their sensitivities and spatial resolutions. Then we describe properties of spinor condensates, ultracold atom magnetometers, and the latest research developments achieved in the FIRST project, especially for the detection of alternate current magnetic fields using a spin-echo-based magnetometer. We also discuss future prospects of the magnetometers.

  5. Cold isopressing method

    DOEpatents

    Chen, Jack C.; Stawisuck, Valerie M.; Prasad, Ravi

    2003-01-01

    A cold isopressing method in which two or more layers of material are formed within an isopressing mold. One of the layers consists of a tape-cast film. The layers are isopressed within the isopressing mold, thereby to laminate the layers and to compact the tape-cast film. The isopressing mold can be of cylindrical configuration with the layers being coaxial cylindrical layers. The materials used in forming the layers can contain green ceramic materials and the resultant structure can be fired and sintered as necessary and in accordance with known methods to produce a finished composite, ceramic structure. Further, such green ceramic materials can be of the type that are capable of conducting hydrogen or oxygen ions at high temperature with the object of utilizing the finished composite ceramic structure as a ceramic membrane element.

  6. The status of cold fusion

    NASA Astrophysics Data System (ADS)

    Storms, E.

    This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

  7. Cloning, expression and structural stability of a cold-adapted ß-Galactosidase from Rahnella sp.R3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel gene was isolated for the first time from a psychrophilic gram-negative bacterium Rahnella sp.R3. It encoded a cold-adapted ß-galactosidase (R-ß-Gal). Recombinant R-ß-Gal was expressed in Escherichia coli BL21 (DE3), purified, and characterized. R-ß-Gal belongs to the glycosyl hydrolase fami...

  8. Thiophene metabolism by E. coli

    SciTech Connect

    Clark, D.P.

    1990-01-01

    The objective of this project is to investigate the mechanism of degradation of sulfur containing heterocyclic molecules by mutants of Escherichia coli K-12. We previously isolated multiple mutants of E. coli which were selected for improved oxidation of furan and thiophene derivatives. We have focused on the thdA mutation in our subsequent research as it appears to be of central importance in thiophene oxidation. We hope that analysis of the thd gene of E. coli will lead to improvement of our thiophene metabolizing bacterial strains.

  9. Thiophene metabolism by E. coli

    SciTech Connect

    Clark, D.P.

    1990-01-01

    The objective of this project is to investigate the mechanism of degradation of sulfur containing heterocyclic molecules such as those found in coal, by mutants of Escherichia coli K-12. We previously isolated multiple mutants of E. coli which were selected for improved oxidation of furan and thiophene derivatives. We have focused on the thdA mutation in our subsequent research as it appears to be of central importance in thiophene oxidation. We hope that analysis of the thd genes of E. coli will lead to improvement of our thiophene metabolizing bacterial strains. 1 tab.

  10. Bacteriophage-based rapid and sensitive detection of Escherichia coli O157:H7 isolates from ground beef

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated efficacy of bacteriophage-based detection technology to detect Escherichia coli O157:H7 from ground beef. The assay involved 8 h enrichment of cold stressed beef samples in presence of antimicrobials followed by capture of the pathogen on O157:H7-specific immunomagnetic beads and sp...

  11. Common cold - how to treat at home

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000466.htm Common cold - how to treat at home To use the ... green snot, and sneezing Sore throat Treating your Cold Treating your symptoms will not make your cold ...

  12. Cold-Weather Sports and Your Family

    MedlinePlus

    ... 5 Things to Know About Zika & Pregnancy Cold-Weather Sports and Your Family KidsHealth > For Parents > Cold- ... once the weather turns frosty. Beating the Cold-Weather Blahs Once a chill is in the air, ...

  13. Cold dark matter halos

    NASA Astrophysics Data System (ADS)

    Dubinski, John Joseph

    The dark halos arising in the Cold Dark Matter (CDM) cosmology are simulated to investigate the relationship between the structure and kinematics of dark halos and galaxies. Realistic cosmological initial conditions and tidal field boundary conditions are used in N-body simulations of the collapse of density peaks to form dark halos. The core radii of dark halos are no greater than the softening radius, rs = 1.4 kpc. The density profiles can be fit with an analytical Hernquist (1990) profile with an effective power law which varies between -1 in the center to -4 at large radii. The rotation curves of dark halos resemble the flat rotation curves of spiral galaxies in the observed range, 1.5 approximately less than r approximately less than 30 kpc. The halos are strongly triaxial and very flat with (c/a) = 0.50 and (b/a) = 0.71. The distribution of ellipticities for dark halos reaches a maximum at epsilon = 0.5 in contrast to the distribution for elliptical galaxies which peaks at epsilon = 0.2 suggesting that ellipticals are much rounder than dark halos. Dark halos are generally flatter than their progenitor density peaks. The final shape and orientation of a dark halo are largely determined by tidal torquing and are sensitive to changes in the strength and orientation of a tidal field. Dark halos are pressure supported objects with negligible rotational support as indicated by the mean dimensionless spin, lamda = 0.042 +/- 0.024. The angular momentum vector tends to align with the true minor axis of dark halos. Elliptical galaxies have a similar behavior implied by the observation of the tendency for alignment of the rotation vector and the apparent minor axis. The origin of this behavior may be traced to the tendency for tidal torques to misalign with the major axis of a density peak. Tidal torques are found to isotropize the velocity ellipsoids of dark halos at large radii, contrary to the expectation of radially anisotropic velocity ellipsoids in cold collapse

  14. Cold quark matter

    SciTech Connect

    Kurkela, Aleksi; Romatschke, Paul; Vuorinen, Aleksi

    2010-05-15

    We perform an O({alpha}{sub s}{sup 2}) perturbative calculation of the equation of state of cold but dense QCD matter with two massless and one massive quark flavor, finding that perturbation theory converges reasonably well for quark chemical potentials above 1 GeV. Using a running coupling constant and strange quark mass, and allowing for further nonperturbative effects, our results point to a narrow range where absolutely stable strange quark matter may exist. Absent stable strange quark matter, our findings suggest that quark matter in (slowly rotating) compact star cores becomes confined to hadrons only slightly above the density of atomic nuclei. Finally, we show that equations of state including quark matter lead to hybrid star masses up to M{approx}2M{sub {center_dot},} in agreement with current observations. For strange stars, we find maximal masses of M{approx}2.75M{sub {center_dot}}and conclude that confirmed observations of compact stars with M>2M{sub {center_dot}}would strongly favor the existence of stable strange quark matter.

  15. Cold fusion studies

    NASA Astrophysics Data System (ADS)

    Hembree, D. M.; Burchfield, L. A.; Fuller, E. L., Jr.; Perey, F. G.; Mamantov, G.

    1990-06-01

    A series of experiments designed to detect the by-products expected from deuterium fusion occurring in the palladium and titanium cathodes of heavy water, D2O, electrolysis cells is reported. The primary purpose of this account is to outline the integrated experimental design developed to test the cold fusion hypothesis and to report preliminary results that support continuing the investigation. Apparent positive indicators of deuterium fusion were observed, but could not be repeated or proved to originate from the electrochemical cells. In one instance, two large increases in the neutron count rate, the largest of which exceeded the background by 27 standard deviations, were observed. In a separate experiment, one of the calorimetry cells appeared to be producing approximately 18 percent more power that the input value, but thermistor failure prevented an accurate recording of the event as a function of time. In general, the tritium levels in most cells followed the slow enrichment expected from the electrolysis of D2O containing a small amount of tritium. However, after 576 hours of electrolysis, one cell developed a tritium concentration approximately seven times greater than expected level.

  16. Pneumatosis coli in a dog.

    PubMed

    Russell, Nicholas J; Tyrrell, Dayle; Irwin, Peter J; Beck, Catherine

    2008-01-01

    A 17-year-old, castrated male Maltese was presented with chronic polyphagia and a 2-week history of tenesmus, diarrhea, hematochezia, weight loss, and ribbon-like feces. Pneumatosis coli was diagnosed by abdominal radiography. Concurrent hyperadrenocorticism was suspected. The clinical signs of colorectal disease resolved within 2 days of initiating a lowresidue diet and oral metronidazole. Pneumatosis coli should be considered as a differential diagnosis for colorectal disease in dogs. PMID:18175797

  17. Versatile cold atom target apparatus

    SciTech Connect

    Goetz, Simone; Hoeltkemeier, Bastian; Hofmann, Christoph S.; Litsch, Dominic; DePaola, Brett D.; Weidemueller, Matthias

    2012-07-15

    We report on a compact and transportable apparatus that consists of a cold atomic target at the center of a high resolution recoil ion momentum spectrometer. Cold rubidium atoms serve as a target which can be operated in three different modes: in continuous mode, consisting of a cold atom beam generated by a two-dimensional magneto-optical trap, in normal mode in which the atoms from the beam are trapped in a three-dimensional magneto-optical trap (3D MOT), and in high density mode in which the 3D MOT is operated in dark spontaneous optical trap configuration. The targets are characterized using photoionization.

  18. Plants in a cold climate.

    PubMed Central

    Smallwood, Maggie; Bowles, Dianna J

    2002-01-01

    Plants are able to survive prolonged exposure to sub-zero temperatures; this ability is enhanced by pre-exposure to low, but above-zero temperatures. This process, known as cold acclimation, is briefly reviewed from the perception of cold, through transduction of the low-temperature signal to functional analysis of cold-induced gene products. The stresses that freezing of apoplastic water imposes on plant cells is considered and what is understood about the mechanisms that plants use to combat those stresses discussed, with particular emphasis on the role of the extracellular matrix. PMID:12171647

  19. Nonfreezing cold-induced injuries.

    PubMed

    Imray, C H E; Richards, P; Greeves, J; Castellani, J W

    2011-03-01

    Non-freezing cold injury (NFCI) is the Cinderella of thermal injuries and is a clinical syndrome that occurs when tissues are exposed to cold temperatures close to freezing point for sustained periods. NFCI is insidious in onset, often difficult to recognize and problematic to treat, and yet the condition accounts for significant morbidity in both military and civilians who work in cold conditions. Consequently recognition of those at risk, limiting their exposure and the appropriate and timely use of suitable protective equipment are essential steps in trying to reduce the impact of the condition. This review addresses the issues surrounding NFCI. PMID:21465916

  20. Mechanisms of acid resistance in enterohemorrhagic Escherichia coli.

    PubMed Central

    Lin, J; Smith, M P; Chapin, K C; Baik, H S; Bennett, G N; Foster, J W

    1996-01-01

    Enterohemorrhagic strains of Escherichia coli must pass through the acidic gastric barrier to cause gastrointestinal disease. Taking into account the apparent low infectious dose of enterohemorrhagic E. coli, 11 O157:H7 strains and 4 commensal strains of E. coli were tested for their abilities to survive extreme acid exposures (pH 3). Three previously characterized acid resistance systems were tested. These included an acid-induced oxidative system, an acid-induced arginine-dependent system, and a glutamate-dependent system. When challenged at pH 2.0, the arginine-dependent system provided more protection in the EHEC strains than in commensal strains. However, the glutamate-dependent system provided better protection than the arginine system and appeared equally effective in all strains. Because E. coli must also endure acid stress imposed by the presence of weak acids in intestinal contents at a pH less acidic than that of the stomach, the ability of specific acid resistance systems to protect against weak acids was examined. The arginine- and glutamate-dependent systems were both effective in protecting E. coli against the bactericidal effects of a variety of weak acids. The acids tested include benzoic acid (20 mM; pH 4.0) and a volatile fatty acid cocktail composed of acetic, propionic, and butyric acids at levels approximating those present in the intestine. The oxidative system was much less effective. Several genetic aspects of E. coli acid resistance were also characterized. The alternate sigma factor RpoS was shown to be required for oxidative acid resistance but was only partially involved with the arginine- and glutamate-dependent acid resistance systems. The arginine decarboxylase system (including adi and its regulators cysB and adiY) was responsible for arginine-dependent acid resistance. The results suggest that several acid resistance systems potentially contribute to the survival of pathogenic E. coli in the different acid stress environments of

  1. Long-term survival of Escherichia coli in lightweight aggregate filter media of constructed wastewater treatment wetlands.

    PubMed

    Paruch, A M

    2011-01-01

    A laboratory scale experiment on the survival of Escherichia coli in samples of filter media from a horizontal subsurface flow constructed wetland treating domestic wastewater was performed. A concentration of E. coli was examined in samples collected from a wetland filter filled with lightweight aggregates (LWA). All samples testing positive for E. coli contamination were used to examine the effect of storage time on the survival of E. coli at three temperature regimes: cold (4°C), mild (10°C) and warm (22°C). It was found that the mild storage condition favoured the growth and survival of E. coli in the tested LWA media. The growth in samples of the uppermost layer of the media lasted for 5.5 months, during which E. coli reached a maximum concentration of 6.4×10(3) MPN/100 g dry matter in the media. It was also observed that E. coli had a greater capacity to survive for extended periods of time in samples collected from the upper layer of the LWA filter compared to samples taken from the deeper layers. The survival of E. coli in the shallowest samples of the wetland filter was remarkably long and unexpected, lasting for a period of over 14 months. PMID:21278480

  2. Enterohemorrhagic Escherichia coli Adhesins.

    PubMed

    McWilliams, Brian D; Torres, Alfredo G

    2014-06-01

    Adhesins are a group of proteins in enterohemorrhagic Escherichia coli (EHEC) that are involved in the attachment or colonization of this pathogen to abiotic (plastic or steel) and biological surfaces, such as those found in bovine and human intestines. This review provides the most up-to-date information on these essential adhesion factors, summarizing important historical discoveries and analyzing the current and future state of this research. In doing so, the proteins intimin and Tir are discussed in depth, especially regarding their role in the development of attaching and effacing lesions and in EHEC virulence. Further, a series of fimbrial proteins (Lpf1, Lpf2, curli, ECP, F9, ELF, Sfp, HCP, and type 1 fimbria) are also described, emphasizing their various contributions to adherence and colonization of different surfaces and their potential use as genetic markers in detection and classification of different EHEC serotypes. This review also discusses the role of several autotransporter proteins (EhaA-D, EspP, Saa and Sab, and Cah), as well as other proteins associated with adherence, such as flagella, EibG, Iha, and OmpA. While these proteins have all been studied to varying degrees, all of the adhesins summarized in this article have been linked to different stages of the EHEC life cycle, making them good targets for the development of more effective diagnostics and therapeutics. PMID:26103974

  3. Sunlight inactivation of Escherichia coli in waste stabilization microcosms in a sahelian region (Ouagadougou, Burkina Faso).

    PubMed

    Maïga, Ynoussa; Denyigba, Kokou; Wethe, Joseph; Ouattara, Aboubakar Sidiki

    2009-02-01

    Experiments on sunlight inactivation of Escherichia coli were conducted from November 2006 to June 2007 in eight outdoors microcosms with different depths filled with maturation pond wastewater in order to determine pond depth influence on sunlight inactivation of E. coli. The long-term aim was to maximize sunlight inactivation of waterborne pathogens in waste stabilization ponds (WSPs) in sahelian regions where number of sunny days enable longer exposure of wastewater to sunlight. The inactivation was followed during daylight from 8.00 h to 17.00 h and during the night. Sunlight inactivation rates (K(S)), as a function of cumulative global solar radiation (insolation), were 16 and 24 times higher than the corresponding dark inactivation (K(D)) rates, respectively in cold and warm season. In warm season, E. coli was inactivated far more rapidly. Inactivation of E. coli follows the evolution of radiation during the day. In shallow depth microcosms, E. coli was inactivated far more rapidly than in high depth microcosms. The physical chemical parameters [pH, dissolved oxygen (DO)] of microcosms water were higher in shallow depth microcosms than in high depth microcosms suggesting a synergistic effect of sunlight and these parameters to damage E. coli. To increase the efficiency of the elimination of waterborne bacteria, the use of maturation ponds with intermediate depths (0.4m) would be advisable in view of the high temperatures and thus evaporation recorded in sahelian regions. PMID:19084427

  4. Metabolomic and transcriptomic stress response of Escherichia coli

    PubMed Central

    Jozefczuk, Szymon; Klie, Sebastian; Catchpole, Gareth; Szymanski, Jedrzej; Cuadros-Inostroza, Alvaro; Steinhauser, Dirk; Selbig, Joachim; Willmitzer, Lothar

    2010-01-01

    Environmental fluctuations lead to a rapid adjustment of the physiology of Escherichia coli, necessitating changes on every level of the underlying cellular and molecular network. Thus far, the majority of global analyses of E. coli stress responses have been limited to just one level, gene expression. Here, we incorporate the metabolite composition together with gene expression data to provide a more comprehensive insight on system level stress adjustments by describing detailed time-resolved E. coli response to five different perturbations (cold, heat, oxidative stress, lactose diauxie, and stationary phase). The metabolite response is more specific as compared with the general response observed on the transcript level and is reflected by much higher specificity during the early stress adaptation phase and when comparing the stationary phase response to other perturbations. Despite these differences, the response on both levels still follows the same dynamics and general strategy of energy conservation as reflected by rapid decrease of central carbon metabolism intermediates coinciding with downregulation of genes related to cell growth. Application of co-clustering and canonical correlation analysis on combined metabolite and transcript data identified a number of significant condition-dependent associations between metabolites and transcripts. The results confirm and extend existing models about co-regulation between gene expression and metabolites demonstrating the power of integrated systems oriented analysis. PMID:20461071

  5. Cold nuclear fusion

    NASA Astrophysics Data System (ADS)

    Tsyganov, E. N.; Bavizhev, M. D.; Buryakov, M. G.; Dabagov, S. B.; Golovatyuk, V. M.; Lobastov, S. P.

    2015-07-01

    If target deuterium atoms were implanted in a metal crystal in accelerator experiments, a sharp increase in the probability of DD-fusion reaction was clearly observed when compared with the reaction's theoretical value. The electronic screening potential, which for a collision of free deuterium atoms is about 27 eV, reached 300-700 eV in the case of the DD-fusion in metallic crystals. These data leads to the conclusion that a ban must exist for deuterium atoms to be in the ground state 1s in a niche filled with free conduction electrons. At the same time, the state 2p whose energy level is only 10 eV above that of state 1s is allowed in these conditions. With anisotropy of 2p, 3p or above orbitals, their spatial positions are strictly determined in the lattice coordinate system. When filling out the same potential niches with two deuterium atoms in the states 2p, 3p or higher, the nuclei of these atoms can be permanently positioned without creating much Coulomb repulsion at a very short distance from each other. In this case, the transparency of the potential barrier increases dramatically compared to the ground state 1s for these atoms. The probability of the deuterium nuclei penetrating the Coulomb barrier by zero quantum vibration of the DD-system also increases dramatically. The so-called cold nuclear DD-fusion for a number of years was registered in many experiments, however, was still rejected by mainstream science for allegedly having no consistent scientific explanation. Finally, it received the validation. Below, we outline the concept of this explanation and give the necessary calculations. This paper also considers the further destiny of the formed intermediate state of 4He∗.

  6. Trapping cold molecular hydrogen.

    PubMed

    Seiler, Ch; Hogan, S D; Merkt, F

    2011-11-14

    Translationally cold H(2) molecules excited to non-penetrating |M(J)| = 3 Rydberg states of principal quantum number in the range 21-37 have been decelerated and trapped using time-dependent inhomogeneous electric fields. The |M(J)| = 3 Rydberg states were prepared from the X (1)Σ(+)(u)(v = 0, J = 0) ground state using a resonant three-photon excitation sequence via the B (1)Σ(+)(u)(v = 3, J = 1) and I (1)Π(g) (v = 0, J = 2) intermediate states and circularly polarized laser radiation. The circular polarization of the vacuum ultraviolet radiation used for the B ← X transition was generated by resonance-enhanced four-wave mixing in xenon and the degree of circular polarization was determined to be 96%. To analyse the deceleration and trapping experiments, the Stark effect in Rydberg states of molecular hydrogen was calculated using a matrix diagonalization procedure similar to that presented by Yamakita et al., J. Chem. Phys., 2004, 121, 1419. Particular attention was given to the prediction of zero-field positions of low-l states and of avoided crossings between Rydberg-Stark states with different values of |M(J)|. The calculated Stark maps and probabilities for diabatic traversal of the avoided crossings were used as input to Monte-Carlo particle-trajectory simulations. These simulations provide a quantitatively satisfactory description of the experimental data and demonstrate that particle loss caused by adiabatic traversals of avoided crossings between adjacent |M(J)| = 3 Stark states of H(2) is small at principal quantum numbers beyond n = 25. The main source of trap losses was found to be from collisional processes. Predissociation following the absorption of blackbody radiation is estimated to be the second most important trap-loss mechanism at room temperature, and trap loss by spontaneous emission is negligible under our experimental conditions. PMID:21818497

  7. Flu and Colds: In Depth

    MedlinePlus

    ... Allergy and Infectious Diseases Web site . What the Science Says About Complementary Health Approaches for the Flu ... tea Oscillococcinum Vitamin C Vitamin D What the Science Says About Complementary Health Approaches for Colds The ...

  8. Garlic for the common cold.

    PubMed

    Lissiman, Elizabeth; Bhasale, Alice L; Cohen, Marc

    2014-01-01

    Background Garlic is alleged to have antimicrobial and antiviral properties that relieve the common cold, among other beneficial effects. There is widespread usage of garlic supplements. The common cold is associated with significant morbidity and economic consequences. On average, children have six to eight colds per year and adults have two to four.Objectives To determine whether garlic (Allium sativum) is effective for the prevention or treatment of the common cold, when compared to placebo, no treatment or other treatments.Search methods We searched CENTRAL (2014, Issue 7),OLDMEDLINE (1950 to 1965),MEDLINE (January 1966 to July week 5, 2014), EMBASE(1974 to August 2014) and AMED (1985 to August 2014).Selection criteria Randomised controlled trials of common cold prevention and treatment comparing garlic with placebo, no treatment or standard treatment.Data collection and analysis Two review authors independently reviewed and selected trials from searches, assessed and rated study quality and extracted relevant data.Main results In this updated review, we identified eight trials as potentially relevant from our searches. Again, only one trial met the inclusion criteria.This trial randomly assigned 146 participants to either a garlic supplement (with 180 mg of allicin content) or a placebo (once daily)for 12 weeks. The trial reported 24 occurrences of the common cold in the garlic intervention group compared with 65 in the placebo group (P value < 0.001), resulting in fewer days of illness in the garlic group compared with the placebo group (111 versus 366). The number of days to recovery from an occurrence of the common cold was similar in both groups (4.63 versus 5.63). Only one trial met the inclusion criteria, therefore limited conclusions can be drawn. The trial relied on self reported episodes of the common cold but was of reasonable quality in terms of randomisation and allocation concealment. Adverse effects included rash and odour. Authors' conclusions

  9. Escherichia coli and the Emergence of Molecular Biology.

    PubMed

    Ullmann, Agnes

    2011-12-01

    The creation of the "Phage group" by M. Delbrück, S. E. Luria, and A. D. Hershey in 1940 at Cold Spring Harbor played a crucial role in the development of molecular biology. In the 1940s, working with Escherichia coli and its viruses, Luria and Delbrück discovered the spontaneous nature of bacterial mutations and Hershey described recombination in bacteriophages and demonstrated with M. Chase that the genetic material that infects bacteria is DNA. At the same time, S. Benzer defined the structure of a functional genetic unit and J. Lederberg and E. Tatum discovered sexual recombination between bacteria. Some years later, Lederberg's group discovered extrachromosomal particles, the plasmids, and a novel way of genetic transfer through bacteriophages, called transduction. In 1949, at the Pasteur Institute in Paris, A. Lwoff uncovered the mechanism of lysogeny. Shortly afterwards, F. Jacob and E. Wollman unraveled the mechanism of the sexual process in E. coli and established the circularity of the bacterial chromosome. In the 1960s, J. Monod and F. Jacob, by genetic analysis of the E. coli lactose system, proposed the operon model for gene regulation and introduced the concept of messenger RNA. The elucidation of the double helix structure of DNA in 1953 by F. Crick and J. Watson had major consequences: the establishment of the copying mechanism (Meselson and Stahl), the discovery of the nature of the genetic code (S. Brenner) leading to its deciphering. E. coli and its phages were instrumental in the development of recombinant DNA technology based on the discovery of the restriction-modification system by W. Arber. PMID:26442505

  10. [Cloning and expression of endoglucanase of marine cold-adapted bacteria Pseudoalteromonas sp. MB-1].

    PubMed

    You, Yin-wei; Wang, Tian-hong

    2005-02-01

    The cold-adapted gram-negative rod bacterium MB-1 which could secret cellulase was screened from mud of the bottom of the Huanghai. According to the sequence of 16S rDNA, this bacterium screened was identified as one species of Pseudoalteromonas and was named as Pseudoalteromonas sp. MB-1. The gene celA encoding cold-adapted endogluanase was cloned and then jointed to pGEX-4T-1 to construct expression plasmid pGEX-celA which was expressed in E. coli BL21. Analysis to the supernatant of E. coli sonicate revealed that the concentration of GST-CelA was about 78.5 mg/L. Properties of the fusion enzyme of GST-CelA including the optimum temperature at 35 degrees C and the optimum pH about 7.2, showed that this fusion enzyme still belonged to cold-adapted enzyme and neutral enzyme. The result lays solid base for the fundamental theory and application research on cold-adapted cellulase from Pseudoalteromonas sp. MB-1. PMID:15847183

  11. Expression, purification and characterization of cold shock protein A of Corynebacterium pseudotuberculosis.

    PubMed

    Lindae, Antje; Eberle, Raphael J; Caruso, Icaro P; Coronado, Monika A; de Moraes, Fabio R; Azevedo, Vasco; Arni, Raghuvir K

    2015-08-01

    The gram-positive bacterium Corynebacterium pseudotuberculosis is the causative agent of different diseases that cause dramatically reduced yields of wool and milk, and results in weight loss, carcass condemnation and also death mainly in sheep, equids, cattle and goats and therefore globally results in considerable economical loss. Cold shock proteins are conserved in many bacteria and eukaryotic cells and they help to restore normal cell functions after cold shock in which some appear to have specific functions at normal growth temperature as well. Cold shock protein A from C. pseudotuberculosis was expressed in Escherichia coli and purified. The thermal unfolding/refolding process characterized by circular dichroism, differential scanning calorimetry and NMR spectroscopy techniques indicated that the refolding process was almost completely reversible. PMID:25907380

  12. Spectroscopy with cold and ultra-cold neutrons

    NASA Astrophysics Data System (ADS)

    Abele, Hartmut; Jenke, Tobias; Konrad, Gertrud

    2015-05-01

    We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the R×B drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron β-decay. We aim for a precision on the 10-4 level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.

  13. Caffeine and the common cold.

    PubMed

    Smith, A; Thomas, M; Perry, K; Whitney, H

    1997-01-01

    An experiment was carried out to determine whether caffeinated and decaffeinated coffee removed the malaise (reduced alertness, slower psychomotor performance) associated with having a common cold. One hundred volunteers were tested when healthy and 46 returned to the laboratory when they developed colds. Those subjects who remained healthy were then recalled as a control group. On the second visit subjects carried out two sessions, one pre-drink and another an hour after the drink. Subjects were randomly assigned to one of the following three conditions, caffeinated coffee (1.5 mg/kg caffeine/body weight), decaffeinated coffee or fruit juice. Subjects with colds reported decreased alertness and were slower at performing psychomotor tasks. Caffeine increased the alertness and performance of the colds subjects to the same level as the healthy group and decaffeinated coffee also led to an improvement. These results suggest that drugs which increase alertness can remove the malaise associated with the common cold, and that increased stimulation of the sensory afferent nerves may also be beneficial. PMID:9443519

  14. Cold air systems: Sleeping giant

    SciTech Connect

    MacCracken, C.D. )

    1994-04-01

    This article describes how cold air systems help owners increase the profits from their buildings by reducing electric costs and improving indoor air quality through lower relative humidity levels. Cold air distribution involves energy savings, cost savings, space savings, greater comfort, cleaner air, thermal storage, tighter ducting, coil redesign, lower relative humidities, retrofitting, and improved indoor air quality (IAQ). It opens a door for architects, engineers, owners, builders, environmentalists, retrofitters, designers, occupants, and manufacturers. Three things have held up cold air's usage: multiple fan-powered boxes that ate up the energy savings of primary fans. Cold air room diffusers that provided inadequate comfort. Condensation from ducts, boxes, and diffusers. Such problems have been largely eliminated through research and development by utilities and manufacturers. New cold air diffusers no longer need fan powered boxes. It has also been found that condensation is not a concern so long as the ducts are located in air conditioned space, such as drop ceilings or central risers, where relative humidity falls quickly during morning startup.

  15. Mathematical modeling of cold cap

    SciTech Connect

    Pokorny, Richard; Hrma, Pavel R.

    2012-10-13

    The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional (1D) mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.

  16. Shiga Toxin Producing Escherichia coli.

    PubMed

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli. PMID:26004641

  17. Experimental evolution of E. coli

    NASA Astrophysics Data System (ADS)

    Zhang, Mengshi

    The evolution from unicellular to multicellular behavior is an essential step in the history of life. Our aim is to investigate the emergence of collective behavior in the model organism Escherichia coli (E. coli) and its selection advantages, such as better utilization of public goods. Our preliminary results suggest that the evolution of collective behavior may be a natural response to stressed conditions. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: mengshi0928@gmail.com.

  18. Serogroups of Escherichia coli from drinking water.

    PubMed

    Ramteke, P W; Tewari, Suman

    2007-07-01

    Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli, ETEC) and 0113 (Shiga-toxin producing E. coli, STEC). All the pathogenic serotypes showed resistance to bacitracin and multiple heavy metal ions. Resistance to streptomycin and cotrimazole was detected in two strains whereas resistance to cephaloridine, polymixin-B and ampicillin was detected in one strain each. Transfer of resistances to drugs and metallic ions was observed in 9 out of 12 strains studied. Resistances to bacitracin were transferred in all nine strains. Among heavy metals resistance to As(3+) followed by Cr(6+) were transferred more frequently. PMID:17057960

  19. Predictors and risk factors for the intestinal shedding of Escherichia coli O157 among working donkeys (Equus asinus) in Nigeria

    PubMed Central

    Jedial, Jesse T.; Shittu, Aminu; Tambuwal, Faruk M.; Abubakar, Mikail B.; Garba, Muhammed K.; Kwaga, Jacob P.; Fasina, Folorunso O.

    2015-01-01

    Objectives Escherichia coli are an important group of bacteria in the normal gastrointestinal system but can sometimes cause infections in domestic animals and man. Donkeys are routinely used as multipurpose animal but details of burdens of potentially infectious bacteria associated with it are limited. The prevalence and associations between intestinal shedding of E. coli O157 and animal characteristics and management factors were studied among 240 randomly selected working donkeys in north-western Nigeria. Design Four local government areas, of Sokoto State in north-western Nigeria were recruited in this study. A multistage randomised cluster design was used to select subjects and donkey owners within selected zones. Confirmation of infection was based on bacterial culture, isolation and biochemical test for E. coli O157 from faecal samples. Results Of the total bacteria isolated, 203 of the 329 (61.70 per cent) were E. coli, 76 of which was E. coli serotype O157. A multivariable logistic regression model was used to examine the relation between intestinal shedding of E. coli O157 and selected variables. The analysis yielded five potential predictors of shedding: soft faeces in donkeys, Akaza and Fari ecotypes of donkey were positive predictors while maize straw as feed and sampling during the cold dry period were negative predictors. Conclusions This study concludes that controlling intestinal shedding of E. coli O157 among working donkeys in Nigeria is possible using the identified predictors in planning appropriate interventions to reduced human risk of infection. PMID:26392892

  20. COLD-SAT dynamic model

    NASA Technical Reports Server (NTRS)

    Adams, Neil S.; Bollenbacher, Gary

    1992-01-01

    This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

  1. COLD-SAT dynamic model

    NASA Astrophysics Data System (ADS)

    Adams, Neil S.; Bollenbacher, Gary

    1992-12-01

    This report discusses the development and underlying mathematics of a rigid-body computer model of a proposed cryogenic on-orbit liquid depot storage, acquisition, and transfer spacecraft (COLD-SAT). This model, referred to in this report as the COLD-SAT dynamic model, consists of both a trajectory model and an attitudinal model. All disturbance forces and torques expected to be significant for the actual COLD-SAT spacecraft are modeled to the required degree of accuracy. Control and experimental thrusters are modeled, as well as fluid slosh. The model also computes microgravity disturbance accelerations at any specified point in the spacecraft. The model was developed by using the Boeing EASY5 dynamic analysis package and will run on Apollo, Cray, and other computing platforms.

  2. Gene cloning of cold-adapted isocitrate lyase from a psychrophilic bacterium, Colwellia psychrerythraea, and analysis of amino acid residues involved in cold adaptation of this enzyme.

    PubMed

    Sato, Yuhya; Watanabe, Seiya; Yamaoka, Naoto; Takada, Yasuhiro

    2008-01-01

    The gene (icl) encoding cold-adapted isocitrate lyase (ICL) of a psychrophilic bacterium, Colwellia psychrerythraea, was cloned and sequenced. Open reading frame of the gene was 1,587 bp in length and corresponded to a polypeptide composed of 528 amino acids. The deduced amino acid sequence showed high homology with that of cold-adapted ICL from other psychrophilic bacterium, C. maris (88% identity), but the sequential homology with that of the Escherichia coli ICL was low (28% identity). Primer extension analysis revealed that transcriptional start site for the C. psychrerythraea icl gene was guanine, located at 87 bases upstream of translational initiation codon. The expression of this gene in the cells of an E. coli mutant defective in ICL was induced by not only low temperature but also acetate. However, cis-acting elements for cold-inducible expression known in the several other bacterial genes were absent in the promoter region of the C. psychrerythraea icl gene. The substitution of Ala214 for Ser in the C. psychrerythraea ICL introduced by point mutation resulted in the increased thermostability and lowering of the specific activity at low temperature, indicating that Ala214 is important for psychrophilic properties of this enzyme. PMID:17965824

  3. Molecular Ecology of Waterborne E. coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli is a common inhabitant of surface and ground waters in the developed and developing worlds. The majority of the E coli present in water are not particularly pathogenic to humans; however, there are E coli present in small proportion, that possess virulence genes that allow them to c...

  4. Antihydrogen Formation using Cold Plasmas

    SciTech Connect

    Madsen, N.; Bowe, P.D.; Hangst, J.S.; Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A.; Amsler, C.; Johnson, I.; Pruys, H.; Regenfus, C.; Bonomi, G.; Bouchta, A.; Doser, M.; Kellerbauer, A.; Landua, R.; Cesar, C.L.; Charlton, M.; Joergensen, L.V.

    2004-10-20

    Antihydrogen, the antimatter counterpart of the hydrogen atom, can be formed by mixing cold samples of antiprotons and positrons. In 2002 the ATHENA collaboration succeeded in the first production of cold antihydrogen. By observing and imaging the annihilation products of the neutral, non-confined, antihydrogen atoms annihilating on the walls of the trap we can observe the production in quasi-real-time and study the dynamics of the formation mechanism. The formation mechanism strongly influences the final state of the formed antihydrogen atoms, important for future spectroscopic comparison with hydrogen. This paper briefly summarizes the current understanding of the antihydrogen formation in ATHENA.

  5. EXTRAINTESTINAL PATHOGENIC ESCHERICHIA COLI (EXPEC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extraintestinal pathogenic Escherichia coli (ExPEC) possess virulence traits that allow them to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgic...

  6. Avionics Box Cold Plate Damage Prevention

    NASA Technical Reports Server (NTRS)

    Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

    2012-01-01

    Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

  7. Images of the Cold War.

    ERIC Educational Resources Information Center

    Chomsky, Noam

    1989-01-01

    The conventional U.S. picture traces the Cold War to Soviet violation of wartime agreements, while the U.S.S.R. defends its actions as responses to American violations and foreign adventurism. An understanding of how ideology is shaped by national self-interest will help students see beyond propaganda and myth in interpreting past and current…

  8. Cold War Geopolitics: Embassy Locations.

    ERIC Educational Resources Information Center

    Vogeler, Ingolf

    1995-01-01

    Asserts that the geopolitics of the Cold War can be illustrated by the diplomatic ties among countries, particularly the superpowers and their respective allies. Describes a classroom project in which global patterns of embassy locations are examined and compared. Includes five maps and a chart indicating types of embassy locations. (CFR)

  9. "Stone Cold": Worthy of Study?

    ERIC Educational Resources Information Center

    Douthwaite, Alison

    2015-01-01

    This article draws on my experiences of teaching "Stone Cold" to respond to a blog post suggesting that the novel holds little educational value. I argue that the novel's narrative style helps to foster criticality while its subject matter can help students see the relevance of literature to the world around them. Relating this to…

  10. Cold plasma decontamination of foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma is a novel nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. This flexible sanitizing method uses electricity and a carrier gas such as air, oxygen, nitrogen or helium; antimicrobi...

  11. The Cold Blooded Killer: Hypothermia.

    ERIC Educational Resources Information Center

    Keller, Rosanne

    Part of a series of home literacy readers with conversational text and sketches, this booklet depicts the subarctic Alaskan environment where cold makes extreme demands on body metabolism. Body temperature must be maintained above 80F (26.7C). A condition of too little body-heat is termed hypo- ('deficit') thermia ('heat'). Hypothermia is the…

  12. Lupus - the cold, hard facts.

    PubMed

    Wong, N W K; Ng, Vt-Y; Ibrahim, S; Slessarev, M; Chandran, V

    2014-07-01

    Systemic lupus erythematosus (SLE) is a multisystem chronic disease with a multitude of clinical presentations. We review and synthesize how an environmental insult (exposure to extreme cold for a short duration) and endogenous (antiphospholipid antibody syndrome, SLE vasculitis) insults in a susceptible young female with lupus (peripheral arterial disease, smoking, SLE) led to a perfect storm resulting in catastrophic injuries (frostbite). PMID:24699313

  13. Advances in cold plasma technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogens continue to be an issue on a variety of commodities, prompting research into novel interventions. Cold plasma is a nonthermal food processing technology which uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry and fruits and vegetables. The prim...

  14. EDITORIAL: Cold Quantum GasesEditorial: Cold Quantum Gases

    NASA Astrophysics Data System (ADS)

    Vassen, W.; Hemmerich, A.; Arimondo, E.

    2003-04-01

    This Special Issue of Journal of Optics B: Quantum and Semiclassical Optics brings together the contributions of various researchers working on theoretical and experimental aspects of cold quantum gases. Different aspects of atom optics, matter wave interferometry, laser manipulation of atoms and molecules, and production of very cold and degenerate gases are presented. The variety of subjects demonstrates the steadily expanding role associated with this research area. The topics discussed in this issue, extending from basic physics to applications of atom optics and of cold atomic samples, include: bulletBose--Einstein condensation bulletFermi degenerate gases bulletCharacterization and manipulation of quantum gases bulletCoherent and nonlinear cold matter wave optics bulletNew schemes for laser cooling bulletCoherent cold molecular gases bulletUltra-precise atomic clocks bulletApplications of cold quantum gases to metrology and spectroscopy bulletApplications of cold quantum gases to quantum computing bulletNanoprobes and nanolithography. This special issue is published in connection with the 7th International Workshop on Atom Optics and Interferometry, held in Lunteren, The Netherlands, from 28 September to 2 October 2002. This was the last in a series of Workshops organized with the support of the European Community that have greatly contributed to progress in this area. The scientific part of the Workshop was managed by A Hemmerich, W Hogervorst, W Vassen and J T M Walraven, with input from members of the International Programme Committee who are listed below. The practical aspects of the organization were ably handled by Petra de Gijsel from the Vrije Universiteit in Amsterdam. The Workshop was funded by the European Science Foundation (programme BEC2000+), the European Networks 'Cold Quantum Gases (CQG)', coordinated by E Arimondo, and 'Cold Atoms and Ultraprecise Atomic Clocks (CAUAC)', coordinated by J Henningsen, by the German Physical Society (DFG), by

  15. Cold atmospheric plasma for local infection control and subsequent pain reduction in a patient with chronic post-operative ear infection

    PubMed Central

    Isbary, G; Shimizu, T; Zimmermann, J L; Thomas, H M; Morfill, G E; Stolz, W

    2013-01-01

    Following surgery of cholesteatoma, a patient developed a chronic infection of the external auditory canal, including extended-spectrum β-lactamase producing Escherichia coli, which caused severe pain. The application of cold atmospheric plasma resulted in a significant reduction in pain and clearance of bacterial carriage, allowing antibiotics and analgesics to be ceased. PMID:25356328

  16. Combustion heated cold sealed TEC

    SciTech Connect

    Yarygin, V.I.; Klepikov, V.V.; Meleta, Y.A.; Mikheyev, A.S.; Yarygin, D.V.; Wolff, L.R.

    1997-12-31

    The development of a thermionic domestic boiler system using natural gas, which as performed under an ECS-project in 1992 to 1994 by a Russian-Dutch team of researchers, will be continued again. Thanks to financial support on the part of the Netherlands Organization for Scientific Research (NWO), the major effort in 1997 to 1999 will be focused on the development, manufacture and testing of an improved, easier to fabricate, more repairable and less expensive combustion heated TEC with a longer life-time. The achievement of the aim of this project will make it possible to expand the field of the terrestrial thermionics application and to embark on the commercialization stage. This report discusses the concept of the combustion heated Cold Seal TEC. A Cold Seal TEC will be developed and tested, in which the rubber O-ring seal will electrically insulate the hot shell from the collector heat pipe. The Cold Seal TEC will use a noble gas + cesium as the working medium (the idea of such a TEC was first proposed in 1973 by Professor Musa from Romania). In its cold state, the cesium will short circuit the emitter and the collector. During operation, the interelectrode space will be filled with cesium vapor. The upper part of a Cold Seal TEC will be filled with a noble gas. This noble gas will prevent the O-ring seal from being attacked by the cesium. The TEC output characteristics will be considerably improved by using electrode materials that were developed earlier in the course of an ECS-project for the development of low temperature TEC electrodes.

  17. Cold denaturation of monoclonal antibodies

    PubMed Central

    Lazar, Kristi L; Patapoff, Thomas W

    2010-01-01

    The susceptibility of monoclonal antibodies (mAbs) to undergo cold denaturation remains unexplored. In this study, the phenomenon of cold denaturation was investigated for a mAb, mAb1, through thermodynamic and spectroscopic analyses. tryptophan fluorescence and circular dichroism (CD) spectra were recorded for the guanidine hydrochloride (GuHCl)-induced unfolding of mAb1 at pH 6.3 at temperatures ranging from −5 to 50°C. A three-state unfolding model incorporating the linear extrapolation method was fit to the fluorescence data to obtain an apparent free energy of unfolding, ΔGu, at each temperature. CD studies revealed that mAb1 exhibited polyproline II helical structure at low temperatures and at high GuHCl concentrations. the Gibbs-Helmholtz expression fit to the ΔGu versus temperature data from fluorescence gave a ΔCp of 8.0 kcal mol−1 K−1, a maximum apparent stability of 23.7 kcal mol−1 at 18°C, and an apparent cold denaturation temperature (TCD) of −23°C. ΔGu values for another mAb (mAb2) with a similar framework exhibited less stability at low temperatures, suggesting a depressed protein stability curve and a higher relative TCD. Direct experimental evidence of the susceptibility of mAb1 and mAb2 to undergo cold denaturation in the absence of denaturant was confirmed at pH 2.5. thus, mAbs have a potential to undergo cold denaturation at storage temperatures near −20°C (pH 6.3), and this potential needs to be evaluated independently for individual mAbs. PMID:20093856

  18. Clinical implications of enteroadherent Escherichia coli.

    PubMed

    Arenas-Hernández, Margarita M P; Martínez-Laguna, Ygnacio; Torres, Alfredo G

    2012-10-01

    Pathogenic Escherichia coli that colonize the small intestine primarily cause gastrointestinal illness in infants and travelers. The main categories of pathogenic E. coli that colonize the epithelial lining of the small intestine are enterotoxigenic E. coli, enteropathogenic E. coli, and enteroaggregative E. coli. These organisms accomplish their pathogenic process by a complex, coordinated multistage strategy, including nonintimate adherence mediated by various adhesins. These so called "enteroadherent E. coli" categories subsequently produce toxins or effector proteins that are either secreted to the milieu or injected to the host cell. Finally, destruction of the intestinal microvilli results from the intimate adherence or the toxic effect exerted over the epithelia, resulting in water secretion and diarrhea. In this review, we summarize the current state of knowledge regarding these enteroadherent E. coli strains and the present clinical understanding of how these organisms colonize the human intestine and cause disease. PMID:22798032

  19. Clinical Implications of Enteroadherent Escherichia coli

    PubMed Central

    Arenas-Hernández, Margarita M.P.; Martínez-Laguna, Ygnacio; Torres, Alfredo G.

    2012-01-01

    Pathogenic Escherichia coli that colonize the small intestine primarily cause gastrointestinal illness in infants and travelers. The main categories of pathogenic E. coli that colonize the epithelial lining of the small intestine are enterotoxigenic E. coli enteropathogenic E. coli and enteroaggregative E. coli. These organisms accomplish their pathogenic process by a complex, coordinated multistage strategy, including non-intimate adherence mediated by various adhesins. These so called “enteroadherent E. coli ” categories subsequently produced toxins or effector proteins that are either secreted to the milieu or injected to the host cell. Finally, destruction of the intestinal microvilli results from the intimate adherence or the toxic effect exerted over the epithelia, resulting in water secretion and diarrhea. In this review, we summarize the current state of knowledge regarding these enteroadherent E. coli strains and the present clinical understanding of how these organisms colonize the human intestine and cause disease. PMID:22798032

  20. Infection strategies of enteric pathogenic Escherichia coli

    PubMed Central

    Clements, Abigail; Young, Joanna C.; Constantinou, Nicholas; Frankel, Gad

    2012-01-01

    Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection. PMID:22555463

  1. Assessment of sodium hypochlorite and acidified sodium chlorite as antimicrobial agents to inhibit growth of Escherichia coli O157:H7 and natural microflora on shredded carrots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of cold tap water, sodium hypochlorite (200 ppm) and acidified sodium chlorite (100, 250, 500 and 1000 ppm) washes on survival and growth of Escherichia coli O157:H7 inoculated onto shredded carrots was determined after treatment and 7 and 14 days of storage. Growth of total mesophilic...

  2. Helium Find Thaws the Cold Fusion Trail.

    ERIC Educational Resources Information Center

    Pennisi, E.

    1991-01-01

    Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

  3. Herpes Simplex (Cold Sores and Genital Herpes)

    MedlinePlus

    ... Select a Language: Fact Sheet 508 Herpes Simplex (Cold Sores and Genital Herpes) WHAT IS HERPES? HSV ... virus 1 (HSV1) is the common cause of cold sores (oral herpes) around the mouth. HSV2 normally ...

  4. Gut Microbiota Orchestrates Energy Homeostasis during Cold.

    PubMed

    Chevalier, Claire; Stojanović, Ozren; Colin, Didier J; Suarez-Zamorano, Nicolas; Tarallo, Valentina; Veyrat-Durebex, Christelle; Rigo, Dorothée; Fabbiano, Salvatore; Stevanović, Ana; Hagemann, Stefanie; Montet, Xavier; Seimbille, Yann; Zamboni, Nicola; Hapfelmeier, Siegfried; Trajkovski, Mirko

    2015-12-01

    Microbial functions in the host physiology are a result of the microbiota-host co-evolution. We show that cold exposure leads to marked shift of the microbiota composition, referred to as cold microbiota. Transplantation of the cold microbiota to germ-free mice is sufficient to increase insulin sensitivity of the host and enable tolerance to cold partly by promoting the white fat browning, leading to increased energy expenditure and fat loss. During prolonged cold, however, the body weight loss is attenuated, caused by adaptive mechanisms maximizing caloric uptake and increasing intestinal, villi, and microvilli lengths. This increased absorptive surface is transferable with the cold microbiota, leading to altered intestinal gene expression promoting tissue remodeling and suppression of apoptosis-the effect diminished by co-transplanting the most cold-downregulated strain Akkermansia muciniphila during the cold microbiota transfer. Our results demonstrate the microbiota as a key factor orchestrating the overall energy homeostasis during increased demand. PMID:26638070

  5. Vitamin C and the Common Cold Revisited.

    ERIC Educational Resources Information Center

    Travis, H. Richard

    1984-01-01

    Various studies indicate that Vitamin C does not prevent or cure a cold, but it may ameliorate symptoms in some individuals. The development of a balanced life-style is more effective towards cold prevention. (DF)

  6. Tips to Protect Workers in Cold Environments

    MedlinePlus

    ... Anti-Retaliation Tips To Protect Workers In Cold Environments Prolonged exposure to freezing or cold temperatures may ... 321-OSHA. Freedom of Information Act | Privacy & Security Statement | Disclaimers | Important Web Site Notices | International | Contact Us ...

  7. Cold moderators for pulsed neutron sources

    SciTech Connect

    Carpenter, J.M.

    1990-01-01

    This paper reviews cold moderators in pulsed neutron sources and provides details of the performance of different cold moderator materials and configurations. Analytical forms are presented which describe wavelength spectra and emission time distributions. Several types of cooling arrangements used in pulsed source moderators are described. Choices of materials are surveyed. The author examines some of the radiation damage effects in cold moderators, including the phenomenon of burping'' in irradiated cold solid methane. 9 refs., 15 figs., 4 tabs.

  8. The cold equation of state of tantalum

    SciTech Connect

    Greeff, Carl W; Rudin, Sven P; Corckett, Scott D; Wills, John M

    2009-01-01

    In high-pressure isentropic compression experiments (ICE), the pressure is dominated by the cold curve. In order to obtain an accurate semi-empirical cold curve for Ta, we calculate the thermal pressure from ab initio phonon and electronic excitation spectra. The cold curve is then inferred from ultrasonic and shock data. Our empirical cold pressure is compared to density functional calculations and found to be closer to GGA results at low pressure and to approach LDA at high pressure.

  9. Control and regulation of the cellular responses to cold shock: the responses in yeast and mammalian systems

    PubMed Central

    Al-Fageeh, Mohamed B.; Smales, C. Mark

    2006-01-01

    Although the cold-shock response has now been studied in a number of different organisms for several decades, it is only in the last few years that we have begun to understand the molecular mechanisms that govern adaptation to cold stress. Notably, all organisms from prokaryotes to plants and higher eukaryotes respond to cold shock in a comparatively similar manner. The general response of cells to cold stress is the elite and rapid overexpression of a small group of proteins, the so-called CSPs (cold-shock proteins). The most well characterized CSP is CspA, the major CSP expressed in Escherichia coli upon temperature downshift. More recently, a number of reports have shown that exposing yeast or mammalian cells to sub-physiological temperatures (<30 or <37 °C respectively) invokes a co-ordinated cellular response involving modulation of transcription, translation, metabolism, the cell cycle and the cell cytoskeleton. In the present review, we summarize the regulation and role of cold-shock genes and proteins in the adaptive response upon decreased temperature with particular reference to yeast and in vitro cultured mammalian cells. Finally, we present an integrated model for the co-ordinated responses required to maintain the viability and integrity of mammalian cells upon mild hypothermic cold shock. PMID:16792527

  10. Is It a Cold or an Allergy?

    MedlinePlus

    ... C AT I O N S IS IT A Cold OR AN Allergy  ? COLD Common Slight Sometimes Rare or never Usual Common Common Common Rare 3 to 14 days Cold ■■ Antihistamines ■■ Decongestants ■■ Nonsteroidal anti-inflammatory medicines ■■ Wash your ...

  11. Cold tolerance encoded in one SNP.

    PubMed

    Manishankar, Prabha; Kudla, Jörg

    2015-03-12

    Cold tolerance fundamentally affects world crop harvest. Ma et al. now identify a single-nucleotide polymorphism in a gene called COLD1 that confers cold tolerance in japonica rice. This study reveals important insights into agronomical traits that are essential for human nutrition. PMID:25768901

  12. Catching a Cold When It's Warm

    MedlinePlus

    ... our exit disclaimer . Subscribe Catching a Cold When It’s Warm What’s the Deal with Summertime Sniffles? Most ... be more unfair than catching a cold when it’s warm? How can cold symptoms arise when it’s ...

  13. Thiophene metabolism by E. coli

    SciTech Connect

    Clark, D.P.

    1991-01-01

    The objective of this project is to investigate the mechanism of degradation of sulfur-containing heterocyclic molecules by mutant strains of Escherichia coli K-12. We have previously isolated multiple mutants of E. coli which had gained the capacity to oxidize thiophene compounds and their furan analogs. We have focused on the thdA mutation in our subsequent research, as this appears to be in a regulatory gene central to the thiophene/furan oxidation system. The thdF gene appears to be more directly involved in the oxidation reactions, whereas thdC and thdD are apparently required for increased protection against the toxic effects of thiophene and furan compounds. 4 tabs.

  14. 77 FR 43117 - Meeting of the Cold War Advisory Committee for the Cold War Theme Study

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-23

    ... National Park Service Meeting of the Cold War Advisory Committee for the Cold War Theme Study AGENCY... with the Federal Advisory Committee Act, 5 U.S.C. Appendix, that the Cold War Advisory Committee for the Cold War Theme Study will conduct a teleconference meeting on August 3, 2012. Members of...

  15. Equestrian cold panniculitis in women.

    PubMed

    Beacham, B E; Cooper, P H; Buchanan, C S; Weary, P E

    1980-09-01

    We describe four patients with panniculitis attributable to a combination of cold exposure and equestrian activities. All were young, healthy women who rode horses for at least two consecutive hours per day throughout the winter. Initially, several small, erythematosus, pruritic papules appeared on the superior-lateral portions of one or both thighs. During one week, the lesions progressed to indurated, red-to-violaceous,tender plaques and nodules. Studies for cryofibrinogens and cryoglobulins were negative. The histologic picture was that of a panniculitis with prominent inflammation of veins most notable at the dermal-subcutaneus fat junction. Cold panniculitis is not limited to infancy and childhood. The distribution of lesions in our patients may have been caused, in part, by the use of tight-fitting, uninsulated riding pants. Such attire may have slowed blood flow through the skin, thereby further reducing tissue temperature. PMID:7191239

  16. Cold dark matter heats up.

    PubMed

    Pontzen, Andrew; Governato, Fabio

    2014-02-13

    A principal discovery in modern cosmology is that standard model particles comprise only 5 per cent of the mass-energy budget of the Universe. In the ΛCDM paradigm, the remaining 95 per cent consists of dark energy (Λ) and cold dark matter. ΛCDM is being challenged by its apparent inability to explain the low-density 'cores' of dark matter measured at the centre of galaxies, where centrally concentrated high-density 'cusps' were predicted. But before drawing conclusions, it is necessary to include the effect of gas and stars, historically seen as passive components of galaxies. We now understand that these can inject heat energy into the cold dark matter through a coupling based on rapid gravitational potential fluctuations, explaining the observed low central densities. PMID:24522596

  17. Ultra-cold molecule production.

    SciTech Connect

    Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

    2005-12-01

    The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled.

  18. Cold Spots in Protein Binding.

    PubMed

    Shirian, Jason; Sharabi, Oz; Shifman, Julia M

    2016-09-01

    Understanding the energetics and architecture of protein-binding interfaces is important for basic research and could potentially facilitate the design of novel binding domains for biotechnological applications. It is well accepted that a few key residues at binding interfaces (binding hot spots) are responsible for contributing most to the free energy of binding. In this opinion article, we introduce a new concept of 'binding cold spots', or interface positions occupied by suboptimal amino acids. Such positions exhibit a potential for affinity enhancement through various mutations. We give several examples of cold spots from different protein-engineering studies and argue that identification of such positions is crucial for studies of protein evolution and protein design. PMID:27477052

  19. Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

    NASA Astrophysics Data System (ADS)

    Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

    2009-03-01

    The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

  20. Cold Air Plasma To Decontaminate Inanimate Surfaces of the Hospital Environment

    PubMed Central

    Claro, Tânia; O'Connor, Niall; Cafolla, Anthony A.; Stevens, Niall T.; Daniels, Stephen; Humphreys, Hilary

    2014-01-01

    The hospital environment harbors bacteria that may cause health care-associated infections. Microorganisms, such as multiresistant bacteria, can spread around the patient's inanimate environment. Some recently introduced biodecontamination approaches in hospitals have significant limitations due to the toxic nature of the gases and the length of time required for aeration. This study evaluated the in vitro use of cold air plasma as an efficient alternative to traditional methods of biodecontamination of hospital surfaces. Cultures of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli, and Acinetobacter baumannii were applied to different materials similar to those found in the hospital environment. Artificially contaminated sections of marmoleum, mattress, polypropylene, powder-coated mild steel, and stainless steel were then exposed to a cold air pressure plasma single jet for 30 s, 60 s, and 90 s, operating at approximately 25 W and 12 liters/min flow rate. Direct plasma exposure successfully reduced the bacterial load by log 3 for MRSA, log 2.7 for VRE, log 2 for ESBL-producing E. coli, and log 1.7 for A. baumannii. The present report confirms the efficient antibacterial activity of a cold air plasma single-jet plume on nosocomial bacterially contaminated surfaces over a short period of time and highlights its potential for routine biodecontamination in the clinical environment. PMID:24441156

  1. Cold cathode vacuum discharge tube

    DOEpatents

    Boettcher, Gordon E.

    1998-01-01

    A cold cathode vacuum discharge tube, and method for making same, with an interior surface of the trigger probe coated with carbon deposited by carbon vapor deposition (CVD) or diamond-like carbon (DLC) deposition. Preferably a solid graphite insert is employed in the probe-cathode structure in place of an aluminum bushing employed in the prior art. The CVD or DLC probe face is laser scribed to allow resistance trimming to match available trigger voltage signals and to reduce electrical aging.

  2. A Cold Strontium Ion Source

    NASA Astrophysics Data System (ADS)

    Erickson, Christopher J.; Lyon, Mary; Blaser, Kelvin; Harper, Stuart; Durfee, Dallin

    2010-03-01

    We present a cold ion source for strontium 87. The source is based off of a standard Low-Velocity-Intense-Source (LVIS) for strontium using permanent magnets in place of anti-Helmholtz coils. Atoms from the LVIS are then ionized in a two photon process as they pass a 20kV anode plate. The result is a mono-energetic beam of ions whose velocity is tunable. Applications for the ions include spectroscopy and ion interferometry.

  3. Acclimatization to cold in humans

    NASA Technical Reports Server (NTRS)

    Kaciuba-Uscilko, Hanna; Greenleaf, John E.

    1989-01-01

    This review focuses on the responses and mechanisms of both natural and artificial acclimatization to a cold environment in mammals, with specific reference to human beings. The purpose is to provide basic information for designers of thermal protection systems for astronauts during intra- and extravehicular activities. Hibernation, heat production, heat loss, vascular responses, body insulation, shivering thermogenesis, water immersion, exercise responses, and clinical symptoms and hypothermia in the elderly are discussed.

  4. Cold Atoms and Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Steck, Daniel A.

    2013-12-01

    Recent experiments have focused on realizing and studying asymmetric potential barriers for ultracold atoms. Practically speaking, asymmetric barriers, or "atomtronic diodes", open up newmethods for controlling cold atoms, and possibly methods for laser cooling atoms and molecules that are not amenable to present laser-cooling techniques. More fundamentally, asymmetric barriers are interesting as realizations of the textbook statistical-mechanics scenario of Maxwell's demon. This chapter reviews experimental progress in this area, as well as some related practical and theoretical issues.

  5. Contamination of Hospital Water Supplies in Gilan, Iran, with Legionella pneumophila, Escherichia coli, and Pseudomonas aeruginosa

    PubMed Central

    Ahmadi Jalali Moghadam, Masoumeh; Honarmand, Hamidreza; Asfaram Meshginshahr, Sajad

    2015-01-01

    This study is designed to determine the contamination degree of hospital water supplies with Pseudomonas aeruginosa, Legionella pneumophila, and E. coli in Gilan, Iran. Samples were collected directly into sterile containers and concentrated by centrifuge. Half part of any sample transferred to yeast extract broth and the second part transferred to Trypticase Soy Broth and incubated for 3 days. DNA was extracted by using commercial kit. Four rounds of PCR were performed as follows: multiplex PCR for detecting Pseudomonas aeruginosa, Integron 1, and Metallo-β-lactamases gene; PCR for detecting Legionella pneumophila and mip gene separately; PCR for detecting E. coli; and another PCR for detecting whole bacterial presence. Contamination rates of cold, warm, and incubator water samples with P. aeruginosa, were 16.6%, 37.5%, and 6.8% consequently. Degrees of contamination with L. pneumophila were 3.3%, 9.3%, and 10.9% and with E. coli were zero, 6.2%, and zero. Total bacterial contamination of cold, warm, and incubator water samples was 93.3%, 84.4%, and 89.0% consequently. Metallo-β-lactamases gene was found in 20.0% of all samples. Contamination degree with P. aeruginosa was considerable and with L. pneumophila was moderate. Metallo-β-lactamases gene was found frequently indicating widespread multiple drug resistance bacteria. We suggest using new decontamination method based on nanotechnology. PMID:26448745

  6. Functional expression of a valencene dioxygenase from Pleurotus sapidus in E. coli.

    PubMed

    Zelena, Kateryna; Krings, Ulrich; Berger, Ralf G

    2012-03-01

    Valencene dioxygenase (ValOx) from the edible basidiomycete Pleurotus sapidus converted the sesquiterpene (+)-valencene to the valuable grapefruit flavour (+)-nootkatone and to nootkatols through intermediate hydroperoxides. Expression of the enzyme was carried out in the cytosol and periplasm of Escherichia coli. The heterologous production led to high yields of inclusion bodies. The poor yield of soluble recombinant protein was improved by various strategies including cold shock expression, chaperone co-expression, and employment of mutant E. coli strains. Up to 60 mg of the biologically active, soluble ValOx was produced by cold shock under control of the cspA promoter at 8 °C in the BL21(DE3)Star strain and co-expression of the E. coli trigger factor. The recombinant enzyme, purified using the N-terminal His tag, showed the catalytic properties of the wild-type enzyme, as was confirmed by the LC-MS analysis of hydroperoxide intermediates and GC-MS analysis of the volatile products. PMID:22264428

  7. Axion cold dark matter revisited

    NASA Astrophysics Data System (ADS)

    Visinelli, L.; Gondolo, P.

    2010-01-01

    We study for what specific values of the theoretical parameters the axion can form the totality of cold dark matter. We examine the allowed axion parameter region in the light of recent data collected by the WMAP5 mission plus baryon acoustic oscillations and supernovae [1], and assume an inflationary scenario and standard cosmology. We also upgrade the treatment of anharmonicities in the axion potential, which we find important in certain cases. If the Peccei-Quinn symmetry is restored after inflation, we recover the usual relation between axion mass and density, so that an axion mass ma = (85 ± 3) μeV makes the axion 100% of the cold dark matter. If the Peccei-Quinn symmetry is broken during inflation, the axion can instead be 100% of the cold dark matter for ma < 15 meV provided a specific value of the initial misalignment angle θi is chosen in correspondence to a given value of its mass ma. Large values of the Peccei-Quinn symmetry breaking scale correspond to small, perhaps uncomfortably small, values of the initial misalignment angle θi.

  8. Micro-Kelvin cold molecules.

    SciTech Connect

    Strecker, Kevin E.; Chandler, David W.

    2009-10-01

    We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

  9. The COLD-SAT program

    NASA Technical Reports Server (NTRS)

    Bailey, William J.

    1990-01-01

    The Cryogenic On-Orbit Liquid Depot Storage, Acquisition and Transfer (COLD-SAT) satellite is an experimental spacecraft launched from an expendable launch vehicle which is designed to investigate the systems and technologies required for efficient and reliable management of cryogenic fluid in the reduced-gravity space environment. Future applications such as Space Station, Space Transportation Vehicle (STV), external tank (ET), aft cargo carrier (ACC) propellant scavenging, storage depots, and lunar and interplanetary missions, among others, have provided the impetus to pursue this technology in a timely manner to support the design efforts. A refined conceptual approach has been developed and an overview of the COLD-SAT program is described which includes the following: (1) a definition of the technology needs and the accompanying experimental six-month baseline mission; (2) a description of the experiment subsystem, major features, and rationale for satisfaction of primary and secondary experiment requirements using LH2 as the test fluid; and (3) a presentation of the conceptual design of the COLD-SAT spacecraft subsystems which support the on-orbit experiment with emphasis on those areas which posed the greatest technical challenge.

  10. Mars: Always Cold, Sometimes Wet?

    NASA Technical Reports Server (NTRS)

    Lee, Pascal; McKay, Christoper P.

    2003-01-01

    A synthesis of a diverse suite of observations of H2O-related landforms that are possible Mars analogs from terrestrial polar regions (Devon Island in the Arctic; the Dry Valleys of Antarctica) put into question any requirement for extended episode(s) of warm and wet climate in Mars past. Geologically transient episodes of localized H2O cycling, forced by exogenic impacts, enhanced endogenic heat flow, and/or orbit-driven short-term local environmental change under an otherwise cold, low pressure (=10(exp 2) mbar) global climate, may be sufficient to account for the martian surface's exposed record of aqueous activity. A Mars that was only sometimes locally warm and wet while remaining climatically cold throughout its history is consistent with results (difficulties) encountered in modeling efforts attempting to support warm martian climate hypotheses. Possible analogs from terrestrial cold climate regions for the recent gully features on Mars also illustrate how transient localized aqueous activity might, under specific circumstances, also occur on Mars under the present frigid global climatic regime.