scholarly journals Occurrence of Tn4371-Related Mobile Elements and Sequences in (Chloro)biphenyl-Degrading Bacteria

2001 ◽  
Vol 67 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Dirk Springael ◽  
Annemie Ryngaert ◽  
Christophe Merlin ◽  
Ariane Toussaint ◽  
Max Mergeay
Keyword(s):  
Ralstonia Eutropha ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Mobile Elements ◽  
The Other ◽  
Integrase Gene ◽  
Other Hand ◽  
Catabolic Genes ◽  
Transfer Genes ◽  
Degrading Bacteria

ABSTRACT Tn4371, a 55-kb transposable element involved in the degradation and biphenyl or 4-chlorobiphenyl identified inRalstonia eutropha A5, displays a modular structure including a phage-like integrase gene (int), aPseudomonas-like (chloro)biphenyl catabolic gene cluster (bph), and RP4- and Ti-plasmid-like transfer genes (trb) (C. Merlin, D. Springael, and A. Toussaint, Plasmid 41:40–54, 1999). Southern blot hybridization was used to examine the presence of different regions of Tn4371 in a collection of (chloro)biphenyl-degrading bacteria originating from different habitats and belonging to different bacterial genera. Tn4371-related sequences were never detected on endogenous plasmids. Although the gene probes containing only bph sequences hybridized to genomic DNA from most strains tested, a limited selection of strains, all β-proteobacteria, displayed hybridization patterns similar to the Tn4371 bph cluster. Homology between Tn4371 and DNA of two of those strains, originating from the same area as strain A5, extended outside the catabolic genes and covered the putative transfer region of Tn4371. On the other hand, none of the (chloro)biphenyl degraders hybridized with the outer left part of Tn4371 containing the int gene. Thebph catabolic determinant of the two strains displaying homology to the Tn4371 transfer genes and a third strain isolated from the A5 area could be mobilized to a R. eutropha recipient, after insertion into an endogenous or introduced IncP1 plasmid. The mobilized DNA of those strains included all Tn4371 homologous sequences previously identified in their genome. Our observations show that the bph genes present on Tn4371 are highly conserved between different (chloro)biphenyl-degrading hosts, isolated globally but belonging mainly to the β-proteobacteria. On the other hand, Tn4371-related mobile elements carrying bphgenes are apparently only found in isolates from the environment that provided the Tn4371-bearing isolate A5.

scholarly journals Efficient Degradation of 2,4,6-Trichlorophenol Requires a Set of Catabolic Genes Related to tcp Genes from Ralstonia eutropha JMP134(pJP4)

2003 ◽  
Vol 69 (12) ◽  
pp. 7108-7115 ◽  
Author(s):  
V. Matus ◽  
M. A. Sánchez ◽  
M. Martínez ◽  
B. González
Keyword(s):  
Sole Carbon Source ◽  
Ralstonia Eutropha ◽  
The Other ◽  
Aerobic Bacteria ◽  
Bacterial Strains ◽  
Gene Sequences ◽  
Catabolic Pathway ◽  
Liquid Cultures ◽  
Catabolic Genes ◽  
Maleylacetate Reductase

ABSTRACT 2,4,6-Trichlorophenol (2,4,6-TCP) is a hazardous pollutant. Several aerobic bacteria are known to degrade this compound. One of these, Ralstonia eutropha JMP134(pJP4), a well-known, versatile chloroaromatic compound degrader, is able to grow in 2,4,6-TCP by converting it to 2,6-dichlorohydroquinone, 6-chlorohydroxyquinol, 2-chloromaleylacetate, maleylacetate, and β-ketoadipate. Three enzyme activities encoded by tcp genes, 2,4,6-TCP monooxygenase (tcpA), 6-chlorohydroxyquinol 1,2-dioxygenase (tcpC), and maleylacetate reductase (tcpD), are involved in this catabolic pathway. Here we provide evidence that all these tcp genes are clustered in the R. eutropha JMP134(pJP4) chromosome, forming the putative catabolic operon tcpRXABCYD. We studied the presence of tcp-like gene sequences in several other 2,4,6-TCP-degrading bacterial strains and found two types of strains. One type includes strains belonging to the Ralstonia genus and possessing a set of tcp-like genes, which efficiently degrade 2,4,6-TCP and therefore grow in liquid cultures containing this chlorophenol as a sole carbon source. The other type includes strains belonging to the genera Pseudomonas, Sphingomonas, or Sphingopixis, which do not have tcp-like gene sequences and degrade this pollutant less efficiently and which therefore grow only as small colonies on plates with 2,4,6-TCP. Other than strain JMP134, none of the bacterial strains whose genomes have been sequenced possesses a full set of tcp-like gene sequences.

Year-Round Screening of Noncommercial and Commercial Oysters for the Presence of Human Pathogenic Viruses

2005 ◽  
Vol 68 (9) ◽  
pp. 1853-1859 ◽  
Author(s):  
F. LODDER-VERSCHOOR ◽  
A. M. de RODA HUSMAN ◽  
H. H. J. L. van den BERG ◽  
A. STEIN ◽  
H. M. L. van PELT-HEERSCHAP ◽  
...  
Keyword(s):  
Hepatitis A ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Pancreatic Tissue ◽  
The Other ◽  
Fecal Indicators ◽  
Rt Pcr ◽  
Somatic Coliphages ◽  
Pathogenic Viruses ◽  
Commercial Harvesting

Consumption of virus-contaminated shellfish has caused numerous outbreaks of gastroenteritis and hepatitis worldwide. In The Netherlands, oysters are cultured and imported both for consumption and export; therefore, the presence of noroviruses, rotaviruses, astroviruses, hepatitis A viruses, and enteroviruses was determined in 64 commercial and noncommercial oyster samples. Oysters were collected monthly for 13 months from four different harvesting areas in the Oosterschelde Delta. Oyster samples were classified by determining Escherichia coli levels according to the standards set by the Councils Directive (91/492/EEC). Two of 36 commercial and 2 of 28 noncommercial oyster samples were B-classified and therefore not ready for consumption. All other oyster samples were A-classified. For the detection of viral RNA, 150 mg of hepatopancreatic tissue was subjected to the Qiagen RNeasy Mini Kit, followed by reverse transcriptase (RT)–PCR and Southern blot hybridization. Enterovirus RNA was detected in 14 of 64 oyster samples, of which 4 were from noncommercial oyster harvesting areas and 10 were from commercial harvesting areas. None of the other human pathogenic viruses were detected. The levels of somatic coliphages and F-specific phages were also determined in all 64 oyster samples, with some samples containing high phage levels (>50 PFU/g of hepatopancreatic tissue), but with most samples containing low phage levels (<50 PFU/g of hepato-pancreatic tissue). However, independent of these high or low phage levels, enterovirus RNA could be detected. Thus, commercial oysters can be contaminated with pathogenic viruses, and monitoring only fecal indicators might not sufficiently protect human health.

scholarly journals Class 1 integron element in Thai Acinetobacter baumannii reveals a linkage to the European clone I

2012 ◽  
Vol 1 (1) ◽  
pp. 24-28
Author(s):  
B Thapa ◽  
C Tribuddharat ◽  
S Srifuengfung ◽  
C Dhiraputra
Keyword(s):  
Acinetobacter Baumannii ◽  
Blot Hybridization ◽  
Variable Region ◽  
Southern Blot Hybridization ◽  
Multidrug Resistant ◽  
Dot Blot ◽  
Class 1 Integron ◽  
Integrase Gene ◽  
Class 1 ◽  
Resistance Island

BACKGROUND: Class 1 integron element is innate to most of the multidrug resistant Acinetobacter baumannii and its spread is common among international clones worldwide. The aim of this study was to document the presence of blaVEB-1 harboring class 1 integron element and its gene cassettes in Thai A. baumannii in relation to A. baumannii European clone I, AYE strain. MATERIALS AND METHODS: Thirty seven carbapenem resistant A. baumannii isolates identified in routine microbiology laboratory of Siriraj Hospital, Bangkok were studied. The dot blot hybridization was performed to detect class 1 integron element integrase gene. PCR was used to amplify blaVEB-1, arr2, cmlA, blaOXA-10 resistance cassettes, and variable region of class 1 integron element. blaVEB-1 gene was localized by southern blot hybridization. RESULTS: The prevalence of class 1 integron element was 86.48% in the isolates studied. The blaVEB-1 was present in 7 isolates however the location of blaVEB-1 gene was different in different isolate. Four isolates (Ab03-168, Ab04-28, Ab08-20, and Ab08-22) harbored calss 1 integron element variable region sized 5.5 kb as described in strain AYE. However, blaVEB-1 was only amplified from Ab03-168. The cassette organization in this isolate was 5’CS-aadB-blaVEB-1-arr2-cmlA-blaOXA- 10-aadA1-3’CS. The class 1 integron element similar to the element identified in genomic resistance island, AbaRI of European clone I, AYE was identified in Thai A. baumannii. CONCLUSIONS: blaVEB-1 harboring class 1 integron element with minor cassette variation was identified in Thai A. baumanni isolate which might suggest the spread of this resistant cassette or the spread of the European clone I in Thailand. Monitoring of the global spread of multi-resistant A. baumannii is mandatory to control the spread of resistant genes and this multi-resistant pathogen. DOI: http://dx.doi.org/10.3126/ijim.v1i1.6715Int J Infect Microbiol 2012;1(1):24-28

Distribution of exchanges upon homologous recombination of exogenous DNA in Xenopus laevis oocytes.

Genetics ◽  
1994 ◽  
Vol 138 (2) ◽  
pp. 445-457 ◽  
Author(s):  
D Carroll ◽  
C W Lehman ◽  
S Jeong-Yu ◽  
P Dohrmann ◽  
R J Dawson ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
The Other ◽  
Patch Repair ◽  
Xenopus Laevis Oocytes ◽  
Direct Repeats ◽  
Exogenous Dna ◽  
Single Base Pair ◽  
Recombination Pathway

Abstract Homologous recombination between DNA molecules injected into Xenopus oocyte nuclei was investigated by examining the recovery of information from differentially marked parental sequences. The injected recombination substrate was a linear DNA with terminal direct repeats of 1246 bp; one repeat differed from the other by eight single base-pair substitutions, distributed throughout the region of homology, each of which created or destroyed a restriction enzyme site. Recombination products were recovered and analyzed for their content of the diagnostic sites, either directly by Southern blot-hybridization or after cloning in bacteria. The majority (76%) of the cloned products appeared to be the result of simple exchanges-i.e., there was one sharp transition from sequences derived from one parent to sequences derived from the other. These simple exchanges were concentrated near the ends of the homologous interval and, thus, near the sites of the original molecular ends. Placing marked sites on only one side of the homologous overlap showed that marker recovery was governed largely by the positions of the molecular ends and not by the markers themselves. When a terminal nonhomology was present at one end of the substrate, the yield of recombinants was sharply decreased, but the pattern of exchanges was not affected, suggesting that products from end-blocked substrates arise by the same recombination pathway. Because of considerable evidence supporting a nonconservative, resection-annealing mechanism for recombination in oocytes, we interpret the distribution of exchanges as resulting from long-patch repair of extensive heteroduplex intermediates.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

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