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591.
Tschapek B Pittelkow M Sohn-Bösser L Holtmann G Smits SH Gohlke H Bremer E Schmitt L 《Journal of molecular biology》2011,411(1):36-67
The substrate binding protein AfProX from the Archaeoglobus fulgidus ProU ATP binding cassette transporter is highly selective for the compatible solutes glycine betaine (GB) and proline betaine, which confer thermoprotection to this hyperthermophilic archaeon. A detailed mutational analysis of the substrate binding site revealed the contribution of individual amino acids for ligand binding. Replacement of Arg149 by an Ala residue displayed the largest impact on substrate binding. The structure of a mutant AfProX protein (substitution of Tyr111 with Ala) in complex with GB was solved in the open liganded conformation to gain further insight into ligand binding. In this crystal structure, GB is bound differently compared to the GB closed liganded structure of the wild-type AfProX protein. We found that a network of amino acid side chains communicates the presence of GB toward Arg149, which increases ligand affinity and induces domain closure of AfProX. These results were corroborated by molecular dynamics studies and support the view that Arg149 finalizes the high-affinity state of the AfProX substrate binding protein. 相似文献
592.
Massimo Milan Morgan Smits Giulia Dalla Rovere Silvia Iori Angela Zampieri Lisa Carraro Camillo Martino Chiara Papetti Andrea Ianni Nicola Ferri Marco Iannaccone Tomaso Patarnello Romina Brunetta Claudio Ciofi Lisa Grotta Giuseppe Arcangeli Luca Bargelloni Barbara Cardazzo Giuseppe Martino 《Molecular ecology》2019,28(19):4486-4499
Mass mortalities due to disease outbreaks have recently affected a number of major taxa in marine ecosystems. Climate‐ and pollution‐induced stress may compromise host immune defenses, increasing the risk of opportunistic diseases. Despite growing evidence that mass mortality events affecting marine species worldwide are strongly influenced by the interplay of numerous environmental factors, the reductionist approaches most frequently used to investigate these factors hindered the interpretation of these multifactorial pathologies. In this study, we propose a broader approach based on the combination of RNA‐sequencing and 16S microbiota analyses to decipher the factors underlying mass mortality in the striped venus clam, Chamelea gallina, along the Adriatic coast. On one hand, gene expression profiling and functional analyses of microbial communities showed the over‐expression of several genes and molecular pathways involved in xenobiotic metabolism, suggesting potential chemical contamination in mortality sites. On the other hand, the down‐regulation of several genes involved in immune and stress response, and the over‐representation of opportunistic pathogens such as Vibrio and Photobacterium spp. indicates that these microbial species may take advantage of compromised host immune pathways and defense mechanisms that are potentially affected by chemical exposure, resulting in periodic mortality events. We propose the application of our approach to interpret and anticipate the risks inherent in the combined effects of pollutants and microbes on marine animals in today's rapidly changing environment. 相似文献
593.
van Beilen JB Neuenschwander M Smits TH Roth C Balada SB Witholt B 《Journal of bacteriology》2002,184(6):1722-1732
Rubredoxins (Rds) are essential electron transfer components of bacterial membrane-bound alkane hydroxylase systems. Several Rd genes associated with alkane hydroxylase or Rd reductase genes were cloned from gram-positive and gram-negative organisms able to grow on n-alkanes (Alk-Rds). Complementation tests in an Escherichia coli recombinant containing all Pseudomonas putida GPo1 genes necessary for growth on alkanes except Rd 2 (AlkG) and sequence comparisons showed that the Alk-Rds can be divided in AlkG1- and AlkG2-type Rds. All alkane-degrading strains contain AlkG2-type Rds, which are able to replace the GPo1 Rd 2 in n-octane hydroxylation. Most strains also contain AlkG1-type Rds, which do not complement the deletion mutant but are highly conserved among gram-positive and gram-negative bacteria. Common to most Rds are the two iron-binding CXXCG motifs. All Alk-Rds possess four negatively charged residues that are not conserved in other Rds. The AlkG1-type Rds can be distinguished from the AlkG2-type Rds by the insertion of an arginine downstream of the second CXXCG motif. In addition, the glycines in the two CXXCG motifs are usually replaced by other amino acids. Mutagenesis of residues conserved in either the AlkG1- or the AlkG2-type Rds, but not between both types, shows that AlkG1 is unable to transfer electrons to the alkane hydroxylase mainly due to the insertion of the arginine, whereas the exchange of the glycines in the two CXXCG motifs only has a limited effect. 相似文献
594.
Esther J. Smits Antti J. Tolonen Luc Cluitmans Mark van Gils Bernard A. Conway Rutger C. Zietsma Klaus L. Leenders Natasha M. Maurits 《PloS one》2014,9(5)
Objective
To assess whether standardized handwriting can provide quantitative measures to distinguish patients diagnosed with Parkinson''s disease from age- and gender-matched healthy control participants.Design
Exploratory study. Pen tip trajectories were recorded during circle, spiral and line drawing and repeated character ‘elelelel’ and sentence writing, performed by Parkinson patients and healthy control participants. Parkinson patients were tested after overnight withdrawal of anti-Parkinsonian medication.Setting
University Medical Center Groningen, tertiary care, the Netherlands.Participants
Patients with Parkinson''s disease (n = 10; mean age 69.0 years; 6 male) and healthy controls (n = 10; mean age 68.1 years; 6 male).Interventions
Not applicable.Main Outcome Measures
Movement time and velocity to detect bradykinesia and the size of writing to detect micrographia. A rest recording to investigate the presence of a rest-tremor, by frequency analysis.Results
Mean disease duration in the Parkinson group was 4.4 years and the patients were in modified Hoehn-Yahr stages 1–2.5. In general, Parkinson patients were slower than healthy control participants. Median time per repetition, median velocity and median acceleration of the sentence task and median velocity of the elel task differed significantly between Parkinson patients and healthy control participants (all p<0.0014). Parkinson patients also wrote smaller than healthy control participants and the width of the ‘e’ in the elel task was significantly smaller in Parkinson patients compared to healthy control participants (p<0.0014). A rest-tremor was detected in the three patients who were clinically assessed as having rest-tremor.Conclusions
This study shows that standardized handwriting can provide objective measures for bradykinesia, tremor and micrographia to distinguish Parkinson patients from healthy control participants. 相似文献595.
Joost L. M. Jongen Helwin Smits Tiziana Pederzani Malik Bechakra Mehdi Hossaini Sebastiaan K. Koekkoek Frank J. P. M. Huygen Chris I. De Zeeuw Jan C. Holstege Elbert A. J. Joosten 《PloS one》2014,9(10)
Nerve injury may cause neuropathic pain, which involves hyperexcitability of spinal dorsal horn neurons. The mechanisms of action of spinal cord stimulation (SCS), an established treatment for intractable neuropathic pain, are only partially understood. We used Autofluorescent Flavoprotein Imaging (AFI) to study changes in spinal dorsal horn metabolic activity. In the Seltzer model of nerve-injury induced pain, hypersensitivity was confirmed using the von Frey and hotplate test. 14 Days after nerve-injury, rats were anesthetized, a bipolar electrode was placed around the affected sciatic nerve and the spinal cord was exposed by a laminectomy at T13. AFI recordings were obtained in neuropathic rats and a control group of naïve rats following 10 seconds of electrical stimulation of the sciatic nerve at C-fiber strength, or following non-noxious palpation. Neuropathic rats were then treated with 30 minutes of SCS or sham stimulation and AFI recordings were obtained for up to 60 minutes after cessation of SCS/sham. Although AFI responses to noxious electrical stimulation were similar in neuropathic and naïve rats, only neuropathic rats demonstrated an AFI-response to palpation. Secondly, an immediate, short-lasting, but strong reduction in AFI intensity and area of excitation occurred following SCS, but not following sham stimulation. Our data confirm that AFI can be used to directly visualize changes in spinal metabolic activity following nerve injury and they imply that SCS acts through rapid modulation of nociceptive processing at the spinal level. 相似文献
596.
Metabolism of Styrene Oxide and 2-Phenylethanol in the Styrene-Degrading Xanthobacter Strain 124X 总被引:4,自引:14,他引:4 下载免费PDF全文
S. Hartmans J. P. Smits M. J. van der Werf F. Volkering J. A. M. de Bont 《Applied microbiology》1989,55(11):2850-2855
Styrene oxide and 2-phenylethanol metabolism in the styrene-degrading Xanthobacter sp. strain 124X was shown to proceed via phenylacetaldehyde and phenylacetic acid. In cell extracts 2-phenylethanol was oxidized by a phenazine methosulfate-dependent enzyme, probably a pyrroloquinoline quinone enzyme. Xanthobacter sp. strain 124X also contains a novel enzymatic activity designated as styrene oxide isomerase. Styrene oxide isomerase catalyzes the isomerization of styrene oxide to phenylacetaldehyde. The enzyme was partially purified and shown to have a very high substrate specificity. Of the epoxides tested, styrene oxide was the only substrate transformed. The initial step in styrene metabolism in Xanthobacter sp. strain 124X is oxygen dependent and probably involves oxidation of the aromatic nucleus. 相似文献
597.
Transcriptome‐wide comparison of selenium hyperaccumulator and nonaccumulator Stanleya species provides new insight into key processes mediating the hyperaccumulation syndrome 下载免费PDF全文
598.
599.
Tim Kamber Theo H. M. Smits Fabio Rezzonico Brion Duffy 《Trees - Structure and Function》2012,26(1):227-238
The bacterial plant pathogen Erwinia amylovora causes fire blight, a major disease threat to pome fruit production worldwide with further impact on a wide-range of Rosaceae species. Important factors contributing to the development of the disease were discovered in the last decades. Comparative genomics of the genera Erwinia and Pantoea is coming into focus with the recent availability of complete genome sequences. Insights from comparative genomics now position us to answer fundamental questions regarding the evolution of E. amylovora as a successful pathogen and the critical elements for biocontrol activity of Pantoea spp. This trove of new data promises to reveal novel determinants and to understand interactive pathways for virulence, host range and ecological fitness. The ultimate aim is now to apply genomics and identify the pathogen Achilles heels and antagonist mechanisms of action as targets for designing innovative control strategies for fire blight. 相似文献
600.
Erik F.J. Oosterwerff N. D. Fagel T. Slagboom J. G. P. Tijssen J. P. Herrman P. C. Smits M. J. Suttorp E. Ronner G. J. Laarman M. S. Patterson G. Amoroso M. A. Vink R. J. van der Schaaf F. W. A. Verheugt R. K. Riezebos 《Netherlands heart journal》2016,24(3):173-180