scholarly journals The Left End of IS2: a Compromise between Transpositional Activity and an Essential Promoter Function That Regulates the Transposition Pathway

2004 ◽  
Vol 186 (3) ◽  
pp. 858-865 ◽  
Author(s):  
Leslie A. Lewis ◽  
Edruge Cylin ◽  
Ho Kyung Lee ◽  
Robert Saby ◽  
Wilson Wong ◽  
...  
Keyword(s):  
Second Step ◽  
Inverted Repeats ◽  
Sequence Information ◽  
Linear Element ◽  
Strong Promoter ◽  
Transpositional Activity ◽  
Hybrid Promoter ◽  
Optimal Function ◽  
Replicative Transposition ◽  
Novel Variation

ABSTRACT Cut-and-paste (simple insertion) and replicative transposition pathways are the two classical paradigms by which transposable elements are mobilized. A novel variation of cut and paste, a two-step transposition cycle, has recently been proposed for insertion sequences of the IS3 family. In IS2 this variation involves the formation of a circular, putative transposition intermediate (the minicircle) in the first step. Two aspects of the minicircle may involve its proposed role in the second step (integration into the target). The first is the presence of a highly reactive junction formed by the two abutted ends of the element. The second is the assembly at the minicircle junction of a strong hybrid promoter which generates higher levels of transposase. In this report we show that IS2 possesses a highly reactive minicircle junction at which a strong promoter is assembled and that the promoter is needed for the efficient completion of the pathway. We show that the sequence diversions which characterize the imperfect inverted repeats or ends of this element have evolved specifically to permit the formation and optimal function of this promoter. While these sequence diversions eliminate catalytic activity of the left end (IRL) in the linear element, sufficient sequence information essential for catalysis is retained by the IRL in the context of the minicircle junction. These data confirm that the minicircle is an essential intermediate in the two-step transposition pathway of IS2.

scholarly journals Characterization of IS18, an Element Capable of Activating the Silent aac(6′)-Ij Gene ofAcinetobacter sp. 13 Strain BM2716 by Transposition

1998 ◽  
Vol 42 (10) ◽  
pp. 2759-2761 ◽  
Author(s):  
Eric Rudant ◽  
Patrice Courvalin ◽  
Thierry Lambert
Keyword(s):  
Resistance Gene ◽  
Insertion Sequence ◽  
Resistant Mutant ◽  
Open Reading Frame ◽  
Inverted Repeats ◽  
Aminoglycoside Resistance ◽  
Reading Frame ◽  
Terminal Inverted Repeats ◽  
Hybrid Promoter

ABSTRACT Insertion sequence IS18 was detected by analysis of the spontaneous aminoglycoside resistant mutant Acinetobactersp. 13 strain BM2716-1. Insertion of the element upstream from the silent acetyltransferase gene aac(6′)-Ij created a hybrid promoter that putatively accounts for the expression of the aminoglycoside resistance gene. The 1,074-bp IS18 element contained partially matched (20 out of 26 bases) terminal inverted repeats, one of which overlapped the 3′ end of a 935-bp open reading frame potentially encoding a protein related to the transposases of the IS30 family. IS18 was found in 6 out of 29 strains of Acinetobacter sp. 13 but not in 10 strains each of A. baumannii and A. haemolyticus.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

XRF and PIXE Analysis of light and Dark Adapted Ocular Tissue

1982 ◽  
Vol 40 ◽  
pp. 190-191
Author(s):  
B. J. Panessa ◽  
H. W. Kraner ◽  
J. B. Warren ◽  
K. W. Jones
Keyword(s):  
Trace Metals ◽  
Pigment Epithelium ◽  
Nerve Impulse ◽  
Light Response ◽  
Ocular Tissue ◽  
Emission Spectrometry ◽  
Retinol Dehydrogenase ◽  
Pixe Analysis ◽  
X Ray ◽  
Optimal Function

During photoexcitation the retina requires specific electrolytes and trace metals for optimal function (Na, Mg, Cl, K, Ca, S, P, Cu and Zn). According to Hagins (1981), photoexcitation and generation of a nerve impulse involves the movement of Ca from the rhodopsin-ladened membranes of the rod outer segment (ROS) to the plasmalemma, which in turn decreases the in-flow of Na into the photoreceptor, resulting in hyperpolarization. In toad isolated retinas, the presence of Ba has been found to increase the amplitude and prolong the delay of the light response (Brown and Flaming, 1978). Trace metals such as Cu, Zn and Se are essential for the activity of the metalloenzymes of the retina and retina pigment epithelium (RPE) (i.e. carbonic anhydrase, retinol dehydrogenase, tyrosinase, glutathione peroxidase, superoxide dismutase...). Therefore the content and fluctuations of these elements in the retina and choroid are of fundamental importance for the maintenance of vision. This paper presents elemental data from light and dark adapted frog ocular tissues examined by electron beam induced x-ray microanalysis, x-ray fluorescence spectrometry (XRF) and proton induced x-ray emission spectrometry (PIXE).

The application of video-enhanced constrast/differential interference constrast microscopy in conjunction with whole mount electron microscopy to the study of organelle transport

1988 ◽  
Vol 46 ◽  
pp. 66-67
Author(s):  
J. H. Hayden
Keyword(s):  
Electron Microscopy ◽  
Rana Pipiens ◽  
Silver Film ◽  
Immunofluorescence Microscopy ◽  
Organelle Transport ◽  
Linear Element ◽  
Whole Mount ◽  
Carbon Coated ◽  
Linear Elements ◽  
Dic Microscopy

In a previous study, Allen video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with immunofluorescence microscopy to demonstrate that organelles and vesicle move in either direction along linear elements composed of microtubules. However, this study was limited in that the number of microtubules making up a linear element could not be determined. To overcome this limitation, we have used AVEC-DIC microscopy in conjunction with whole mount electron microscopy.Keratocytes from Rana pipiens were grown on glass coverslips as described elsewhere. Gold London Finder grids were Formvar- and carbon coated, and sterilized by exposure to ultraviolet light. It is important to select a Formvar film that gives a grey reflection when it is floated on water. A silver film is too thick and will detract from the image in the light microscope.

The Application of Protein A-Gold Immunocytochemistry to Studies of Protein Secretion

1985 ◽  
Vol 43 ◽  
pp. 426-429
Author(s):  
George H. Herbener ◽  
Antonio Nanci ◽  
Moise Bendayan
Keyword(s):  
Tissue Section ◽  
Colloidal Gold ◽  
Unit Area ◽  
Protein A ◽  
Extracellular Proteins ◽  
Gold Complex ◽  
Second Step ◽  
Igg Antibodies ◽  
Tissue Sections ◽  
Antigenic Sites

Protein A-gold immunocytochemistry is a two-step, post-embedding labeling procedure which may be applied to tissue sections to localize intra- and extracellular proteins. The key requisite for immunocytochemistry is the availability of the appropriate antibody to react in an immune response with the antigenic sites on the protein of interest. During the second step, protein A-gold complex is reacted with the antibody. This is a non- specific reaction in that protein A will combine with most IgG antibodies. The ‘label’ visualized in the electron microscope is colloidal gold. Since labeling is restricted to the surface of the tissue section and since colloidal gold is particulate, labeling density, i.e., the number of gold particles per unit area of tissue section, may be quantitated with ease and accuracy.

Perception of Sequence Information

2005 ◽  
Author(s):  
An Oskarsson ◽  
Reid Hastie ◽  
Gary H. McClelland ◽  
Leaf Van Boven
Keyword(s):  
Sequence Information

Drawing enhances item information but undermines sequence information in memory.

2019 ◽  
Vol 45 (4) ◽  
pp. 689-699 ◽  
Author(s):  
Tanya R. Jonker ◽  
Jeffrey D. Wammes ◽  
Colin M. MacLeod
Keyword(s):  
Item Information ◽  
Sequence Information

Thrombolysis in Arterial Occlusion

1999 ◽  
Vol 82 (S 01) ◽  
pp. 109-111 ◽  
Author(s):  
Raymond Verhaeghe
Keyword(s):  
Clinical Practice ◽  
Thrombolytic Therapy ◽  
Hemorrhagic Stroke ◽  
Surgical Intervention ◽  
Bypass Graft ◽  
Surgical Techniques ◽  
Arterial Occlusion ◽  
Second Step ◽  
Severe Bleeding ◽  
Initial Management

SummaryIntra-arterial thrombolytic therapy has replaced systemic intravenous infusion of thrombolytic agents as a treatment modality for arterial occlusion in the limbs. Several catheter-guided techniques and various infusion methods and schemes have been developed. At present there is no scientific proof of definite superiority of any agent in terms of efficacy or safety but clinical practice favours the use of urokinase or alteplase. Studies which compared thrombolysis to surgical intervention suggest that thrombolytic therapy is an appropriate initial management in patients with acute occlusion of a native leg artery or a bypass graft. Underlying causative lesions are treated in a second step by endovascular or open surgical techniques. Severe bleeding is the most feared complication: the risk of hemorrhagic stroke is 1-2%.

Pediatric Replantation after Traumatic Amputation at the Distal Forearm: Rehabilitation Protocol and Outcomes

2020 ◽  
Author(s):  
Nicholas C. Oleck ◽  
Radhika Malhotra ◽  
Haripriya S. Ayyala ◽  
Ramazi O. Datiashvili
Keyword(s):  
Operating Room ◽  
Multidisciplinary Team ◽  
Distal Forearm ◽  
Left Forearm ◽  
Traumatic Amputation ◽  
Postoperative Rehabilitation ◽  
Rehabilitation Protocol ◽  
Microsurgical Technique ◽  
Optimal Function ◽  
And Function

AbstractMajor limb replantation is a formidable task, especially in the pediatric setting. While meticulous microsurgical technique is required in the operating room, the authors aim to highlight the importance of postoperative rehabilitation therapy for optimal function. We highlight the case of a 12-year-old boy who suffered complete traumatic amputation through the distal left forearm. The limb was successfully replanted with successful restoration of sensation and function with the aid of intensive postoperative occupational therapy. A multidisciplinary team is of paramount importance to maximize function of a replanted upper extremity.

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