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1

Measurement of background translocation frequencies in individuals with clones  

SciTech Connect

In the leukemia case the unseparated B and T lymphocytes had a high translocation frequency even after 0.0014, respectively. After purging all clones from the data, the translocation frequencies for Bio 8 and Bio 23 were 0.00750.0014 and 0.0073 metaphases were scored for chromosomal aberrations,, specifically reciprocal translocations, using fluorescence in situ hybridization (FISH). Metaphase spreads were used from two healthy, unexposed individuals (not exposed to radiation, chemotherapy or radiotherapy) and one early B- precursor acute lymphocytic leukemia (ALL) patient (metaphase spreads from both separated T lymphocytes and unseparated B and T lymphocytes were scored). All three individuals had an abnormally high translocation frequency. The high translocation frequencies resulted from clonal expansion of specific translocated chromosomes. I show in this thesis that by purging (discounting or removing) clones from the data of unexposed individuals, one can obtain true background translocation frequencies. In two cases, Bio 8 and Bio 23, the measured translocation frequency for chromosomes 1, 2 and 4 was 0.0124 purging all of the clones from the data. This high translocation frequency may be due to a low frequency of some clones and may not be recognized. The separated T lymphocytes had a higher translocation frequency than expected.

Wade, M.J.

1996-08-01

2

Measurement of background translocation frequencies in individuals with clones.  

National Technical Information Service (NTIS)

In the leukemia case the unseparated B and T lymphocytes had a high translocation frequency even after 0.0014, respectively. After purging all clones from the data, the translocation frequencies for Bio 8 and Bio 23 were 0.00750.0014 and 0.0073 metaphases...

M. J. Wade

1996-01-01

3

High dietary antioxidant intakes are associated with decreased chromosome translocation frequency in airline pilots1234  

PubMed Central

Background: Dietary antioxidants may protect against DNA damage induced by endogenous and exogenous sources, including ionizing radiation (IR), but data from IR-exposed human populations are limited. Objective: The objective was to examine the association between the frequency of chromosome translocations, as a biomarker of cumulative DNA damage, and intakes of vitamins C and E and carotenoids in 82 male airline pilots. Design: Dietary intakes were estimated by using a self-administered semiquantitative food-frequency questionnaire. Translocations were scored by using fluorescence in situ hybridization with whole chromosome paints. Negative binomial regression was used to estimate rate ratios and 95% CIs, adjusted for potential confounders. Results: Significant and inverse associations were observed between translocation frequency and intakes of vitamin C, ?-carotene, ?-cryptoxanthin, and lutein-zeaxanthin from food (P < 0.05). Translocation frequency was not associated with the intake of vitamin E, ?-carotene, or lycopene from food; total vitamin C or E from food and supplements; or vitamin C or E or multivitamin supplements. The adjusted rate ratios (95% CI) for ?median compared with

Petersen, Martin R; Sigurdson, Alice J; Sampson, Laura A; Ward, Elizabeth M

2009-01-01

4

Stability of the translocation frequency following whole-body irradiation measured in rhesus monkeys  

NASA Technical Reports Server (NTRS)

Chromosome translocations are persistent indicators of prior exposure to ionizing radiation and the development of 'chromosome painting' to efficiently detect translocations has resulted in a powerful biological dosimetry tool for radiation dose reconstruction. However, the actual stability of the translocation frequency with time after exposure must be measured before it can be used reliably to obtain doses for individuals exposed years or decades previously. Human chromosome painting probes were used here to measure reciprocal translocation frequencies in cells from two tissues of 8 rhesus monkeys (Macaca mulatta) irradiated almost three decades previously. Six of the monkeys were exposed in 1965 to whole-body (fully penetrating) radiation and two were unexposed controls. The primates were irradiated as juveniles to single doses of 0.56, 1.13, 2.00, or 2.25 Gy. Blood lymphocytes (and skin fibroblasts from one individual) were obtained for cytogenetic analysis in 1993, near the end of the animals' lifespans. Results show identical dose-response relationships 28 y after exposure in vivo and immediately after exposure in vitro. Because chromosome aberrations are induced with identical frequencies in vivo and in vitro, these results demonstrate that the translocation frequencies induced in 1965 have not changed significantly during the almost three decades since exposure. Finally, our emerging biodosimetry data for individual radiation workers are now confirming the utility of reciprocal translocations measured by FISH in radiation dose reconstruction.

Lucas, J. N.; Hill, F. S.; Burk, C. E.; Cox, A. B.; Straume, T.

1996-01-01

5

Increased Frequency of Chromosome Translocations Associated with Diagnostic X-Ray Examinations  

PubMed Central

Informative studies of cancer risks associated with medical radiation are difficult to conduct owing to low radiation doses, poor recall of diagnostic X rays, and long intervals before cancers occur. Chromosome aberrations have been associated with increased cancer risk and translocations are a known radiation biomarker. Seventy-nine U.S. radiologic technologists were selected for blood collection, and translocations were enumerated by whole chromosome painting. We developed a dose score to the red bone marrow for medical radiation exposure from X-ray examinations reported by the technologists that they received as patients. Using Poisson regression, we analyzed translocations in relation to the dose scores. Each dose score unit approximated 1 mGy. The estimated mean cumulative red bone marrow radiation dose score was 42 (range 1–265). After adjustment for age, occupational radiation, and radiotherapy for benign conditions, translocation frequencies significantly increased with increasing red bone marrow dose score with an estimate of 0.007 translocations per 100 CEs per score unit (95% CI, 0.002 to 0.013; P = 0.01). Chromosome damage has been linked with elevated cancer risk, and we found that cumulative radiation exposure from medical X-ray examinations was associated with increased numbers of chromosome translocations.

Bhatti, Parveen; Doody, Michele M.; Preston, Dale L.; Kampa, Diane; Ron, Elaine; Weinstock, Robert W.; Simon, Steven; Edwards, Alan A.; Sigurdson, Alice J.

2009-01-01

6

A biophysical model for estimating the frequency of radiation-induced mutations resulting from chromosomal translocations  

NASA Astrophysics Data System (ADS)

Gene mutations can be induced by radiation as a result of chromosomal translocations. A biophysical model is developed to estimate the frequency of this type of mutation induced by low-LET radiation. Mutations resulting from translocations are assumed to be formed by misrejoining of two DNA double strand breaks (DSB), one within the gene and one on a different chromosome. The chromosome containing the gene is assumed to occupy a spherical territory and does not overlap spatially with other chromosomes. Misrejoining between two DSB can occur only if the two DSB are closer than an interaction distance at the time of their induction. Applying the model to mutations of the hprt gene induced in G0 human lymphocyte cells by low-LET radiation, it is calculated that mutations resulting from translocations account for about 14% of the total mutations. The value of the interaction distance is determined to be 0.6 ?m by comparing with the observed frequency of translocations in the X-chromosome.

Wu, Honglu; Durante, Marco

7

Translocation frequencies and chromosomal proximities for selected mouse chromosomes in primary B lymphocytes.  

PubMed

Chromosome positions within the nucleus of mammalian cells are nonrandom and it is assumed that chromosomal neighborhoods affect the probability of translocations. Four chromosomes can be involved in c-myc-activating chromosomal translocations in mouse plasmacytoma (PCT): the c-myc gene on mouse chromosome 15 can be juxtaposed to either one of the immunoglobulin (Ig) loci on chromosomes 12 (IgH), 16 (Ig?), or 6 (Ig?). In the BALB/c mouse, the translocation between chromosomes 12 and 15, T(12;15), is most common (90%) while the other two possible translocations, T(6;15) and T(16;15), are much less common (<10%). In contrast, in the BALB/cRb6.15 mouse, T(6;15) is found with the same frequency as T(12;15). We, therefore, examined the distance between chromosomes 15 and 12, 6, and 16 in primary mouse B lymphocytes in order to examine the effect of the chromosome proximity on the translocation frequency. We performed three-dimensional fluorescent in situ hybridization (3D-FISH) with chromosome paints. We acquired three-dimensional image stacks with 90 slices per stack and used constrained iterative deconvolution. The nucleus and chromosomes were segmented from this image stack and the interchromosomal distances were measured. Chromosomes 6 and 15 were found in close proximity in BALB/cRb6.15 mice (82%), whereas they did not share this neighborhood relationship in BALB/c mice. No other chromosome combinations showed such a high percentage of close proximities in either mouse strain. Chromosome positions contribute to translocation frequencies in mouse PCTs. The BALB/cRb6.15 mouse data argue for a proximity relationship of chromosomes that engage in illegitimate recombination. These positions are not, however, the only contributing factor as the T(12;15) translocation preference in BALB/c mice could not be supported by significantly elevated proximity of chromosomes 12 and 15 versus 12 and 16 or 12 and 6. Moreover, while there is a significant increase in T(6;15) in BALB/cRb6.15 mice, T(12;15) still occurs in this mouse strain. PMID:21387545

Righolt, Christiaan H; Wiener, Francis; Taylor-Kashton, Cheryl; Harizanova, Jana; Vermolen, Bart J; Garini, Yuval; Young, Ian T; Mai, Sabine

2011-04-01

8

Ultra-low-frequency background radiation of the Galaxy.  

NASA Astrophysics Data System (ADS)

The paper examines the lowest frequency observations of the galactic radio noise published by Brown (1973) and their relationship to the properties of the local interstellar medium. We find that the Razin cut-off frequency in the warm gas is about 0.3MHz and nearly constant, which provides a sharp decrease of the galactic spectrum at f<0.6MHz. The synchrotron emissivity in the tenuous (coronal) gas is found to be much less than that in the warm gas, while it is responsible for the observed excess of the emission at 0.13frequencies if we accept the fluctuation level found from pulsar scintillations and some realistic distribution of the mean plasma density. Compton emission on small scale magnetic and electric fields is shown to be unimportant in the specified conditions. We conclude that new observations at lower frequencies are required to obtain further important knowledge on free electron inhomogeneous distribution in the very local interstellar medium.

Fleishman, G. D.; Tokarev, Yu. V.

1995-01-01

9

Background  

Cancer.gov

Extensive evidence has demonstrated that 24-hour dietary recalls provide the highest quality, least biased dietary data. Traditional 24-hour recalls, however, are expensive and impractical for large-scale research because they rely on trained interviewers and multiple administrations to estimate usual intakes. As a result, researchers often make use of food frequency questionnaires, which are less expensive but contain substantial error.

10

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host  

PubMed Central

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis.

Alaish, Samuel M.; Smith, Alexis D.; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P.; Cross, Alan S

2013-01-01

11

Gut microbiota, tight junction protein expression, intestinal resistance, bacterial translocation and mortality following cholestasis depend on the genetic background of the host.  

PubMed

Failure of the intestinal barrier is a characteristic feature of cholestasis. We have previously observed higher mortality in C57BL/6J compared with A/J mice following common bile duct ligation (CBDL). We hypothesized the alteration in gut barrier function following cholestasis would vary by genetic background. Following one week of CBDL, jejunal TEER was significantly reduced in each ligated mouse compared with their sham counterparts; moreover, jejunal TEER was significantly lower in both sham and ligated C57BL/6J compared with sham and ligated A/J mice, respectively. Bacterial translocation to mesenteric lymph nodes was significantly increased in C57BL/6J mice vs. A/J mice. Four of 15 C57BL/6J mice were bacteremic; whereas, none of the 17 A/J mice were. Jejunal IFN-? mRNA expression was significantly elevated in C57BL/6J compared with A/J mice. Western blot analysis demonstrated a significant decrease in occludin protein expression in C57BL/6J compared with A/J mice following both sham operation and CBDL. Only C57BL/6J mice demonstrated a marked decrease in ZO-1 protein expression following CBDL compared with shams. Pyrosequencing of the 16S rRNA gene in fecal samples showed a dysbiosis only in C57BL/6J mice following CBDL when compared with shams. This study provides evidence of strain differences in gut microbiota, tight junction protein expression, intestinal resistance and bacterial translocation which supports the notion of a genetic predisposition to exaggerated injury following cholestasis. PMID:23652772

Alaish, Samuel M; Smith, Alexis D; Timmons, Jennifer; Greenspon, Jose; Eyvazzadeh, Daniel; Murphy, Ebony; Shea-Donahue, Terez; Cirimotich, Shana; Mongodin, Emmanuel; Zhao, Aiping; Fasano, Alessio; Nataro, James P; Cross, Alan

2013-01-01

12

The critical frequency of the large-scale vortices and the background turbulence in desert area  

NASA Astrophysics Data System (ADS)

Based on the analysis of the experimental data obtained in a desert area, this study investigated the variations of the critical frequency discriminating the large-scale vortices and the background turbulence with the distance above the ground surface and the inflow velocity. The results show that the critical frequency decreases with the reciprocal of the wall-normal distance and increases linearly with the inflow velocity. The effect of the surface properties were also considered in this study, and finally the fitting formula of the critical frequency with respect to the wall-normal distance and the inflow velocity was given.

Wang, Guohua; Bo, Tianli; Zhang, Jinghong; Zhu, Dezhen; Zheng, Xiaojing

2014-06-01

13

The temperature of the cosmic microwave background radiation at a frequency of 10 GHz  

Microsoft Academic Search

We have measured the temperature of the cosmic microwave background radiation (CMBR) at a frequency of 10 GHz (wavelength 3.0 cm) as part of a larger effort to determine the spectrum of the CMBR in the Rayleigh-Jeans region. The instrument used is a superheterodyne Dicke-switched radiometer. We have repeated the measurement over four summers with successively improved techniques and equipment.

A. Kogut; M. Bersanelli; G. de Amici; S. D. Friedman; M. Griffith; B. Grossan; S. Levin; G. F. Smoot; C. Witebsky

1988-01-01

14

Position and frequency shifts induced by massive modes of the gravitational wave background in alternative gravity  

SciTech Connect

Alternative theories of gravity predict the presence of massive scalar, vector, and tensor gravitational wave modes in addition to the standard massless spin 2 graviton of general relativity. The deflection and frequency shift effects on light from distant sources propagating through a stochastic background of gravitational waves, containing such modes, differ from their counterparts in general relativity. Such effects are considered as a possible signature for alternative gravity in attempts to detect deviations from Einstein's gravity by astrophysical means.

Bellucci, Stefano [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044 Frascati (Italy); Capozziello, Salvatore; De Laurentis, Mariafelicia [Dip. di Scienze Fisiche, Universita di Napoli 'Federico II' and INFN Sez. di Napoli, Compl. Universitario Monte S. Angelo, Ed. N, Via Cinthia, I-80126 Napoli (Italy); Faraoni, Valerio [Physics Department, Bishop's University, Sherbrooke, Quebec, Canada J1M 1Z7 (Canada)

2009-05-15

15

Short Segment Frequency Equalization: A Simple and Effective Alternative Treatment of Background Models in Motif Discovery  

NASA Astrophysics Data System (ADS)

One of the most important pattern recognition problems in bioinformatics is the de novo motif discovery. In particular, there is a large room of improvement in motif discovery from eukaryotic genome, where the sequences have complicated background noise. The short segment frequency equalization (SSFE) is a novel treatment method to incorporate Markov background models into de novo motif discovery algorithms, namely Gibbs sampling. Despite its apparent simplicity, SSFE shows a large performance improvement over the current method ( Q/P scheme) when tested on artificial DNA datasets with Markov background of human and mouse. Furthermore, SSFE shows a better performance than other methods including much more complicated and sophisticated method, Weeder 1.3, when tested with several biological datasets from human promoters.

Shida, Kazuhito

16

Multi-frequency survey of background radiations of the Universe. The "Cosmological Gene" project. First results  

NASA Astrophysics Data System (ADS)

The results of the first stage of the "Cosmological Gene" project of the Russian Academy of Sciences are reported. These results consist in the accumulation of multi-frequency data in 31 frequency channels in the wavelength interval 1-55 cm with maximum achievable statistical sensitivity limited by the noise of background radio sources at all wavelengths exceeding 1.38 cm. The survey region is determined by constraints 00 h < RA < 24 h and 40°30' < DEC < 42°30'. The scientific goals of the project are refined in view of recent proposals to use cosmological background radiation data for the development of a unified physical theory. Experimental data obtained with the RATAN-600 radio telescope are used to refine the contribution of the main "screens" located between the observer and the formation epoch of cosmic background radiation ( z = 1100). Experimental data for synchrotron radiation and free-free noise on scales that are of interest for the anisotropy of cosmic microwave background are reported as well as the contribution of these noise components in millimeter-wave experiments to be performed in the nearest years. The role of dipole radio emission of fullerene-type dust nanostructures is shown to be small. The most precise estimates of the role of background radio sources with inverted spectra are given and these sources are shown to create no serious interference in experiments. The average spectral indices of the weakest sources of the NVSS and FIRST catalogs are estimated. The "saturation" data for all wavelengths allowed a constraint to be imposed on the Sunyaev-Zeldovich noise (the SZ noise) at all wavelengths, and made it possible to obtain independent estimates of the average sky temperature from sources, substantially weaker than those listed in the NVSS catalog. These estimates are inconsistent with the existence of powerful extragalactic synchrotron background associated with radio sources. Appreciable "quadrupole" anisotropy in is detected in the distribution of the spectral index of the synchrotron radiation of the Galaxy, and this anisotropy should be taken into account when estimating the polarization of the cosmic microwave background on small l. All the results are compared to the results obtained by foreign researchers in recent years.

Parijskij, Yu. N.; Mingaliev, M. G.; Nizhel'Skii, N. A.; Bursov, N. N.; Berlin, A. B.; Grechkin, A. A.; Zharov, V. I.; Zhekanis, G. V.; Majorova, E. K.; Semenova, T. A.; Stolyarov, V. A.; Tsybulev, P. G.; Kratov, D. V.; Udovitskii, R. Yu.; Khaikin, V. B.

2011-10-01

17

Towards a High Temporal Frequency Grass Canopy Thermal IR Model for Background Signatures  

NASA Technical Reports Server (NTRS)

In this paper, we present our first results towards understanding high temporal frequency thermal infrared response from a dense plant canopy and compare the application of our model, driven both by slowly varying, time-averaged meteorological conditions and by high frequency measurements of local and within canopy profiles of relative humidity and wind speed, to high frequency thermal infrared observations. Previously, we have employed three-dimensional ray tracing to compute the intercepted and scattered radiation fluxes and for final scene rendering. For the turbulent fluxes, we employed simple resistance models for latent and sensible heat with one-dimensional profiles of relative humidity and wind speed. Our modeling approach has proven successful in capturing the directional and diurnal variation in background thermal infrared signatures. We hypothesize that at these scales, where the model is typically driven by time-averaged, local meteorological conditions, the primary source of thermal variance arises from the spatial distribution of sunlit and shaded foliage elements within the canopy and the associated radiative interactions. In recent experiments, we have begun to focus on the high temporal frequency response of plant canopies in the thermal infrared at 1 second to 5 minute intervals. At these scales, we hypothesize turbulent mixing plays a more dominant role. Our results indicate that in the high frequency domain, the vertical profile of temperature change is tightly coupled to the within canopy wind speed In the results reported here, the canopy cools from the top down with increased wind velocities and heats from the bottom up at low wind velocities. .

Ballard, Jerrell R., Jr.; Smith, James A.; Koenig, George G.

2004-01-01

18

A measurement of the low frequency spectrum of the cosmic microwave background radiation  

SciTech Connect

As part of a larger effort to measure the spectrum of the Cosmic Background Radiation (CBR) at low frequencies, the intensity of the CBR has been measured at a frequency of 1.410 GHz. The measurement was made by comparing the power received from the sky with the power received from a specially designed cooled calibration target with known properties. Sources of radiation other than the CBR were then identified and subtracted to calculate the antenna temperature of the CBR at 1.410 GHz. The instrument used to measure the CBR was a total-power microwave radiometer with a 25 MHz bandwidth centered at 1.410 GHz. The radiometer had a noise temperature of 80 K, and sufficient data were taken that radiometer noise did not contribute significantly to the total measurement error. The sources of error were predominantly systematic in nature, and the largest error was due to uncertainty in the reflection characteristics of the cold-load calibrator. Identification and subtraction of signals from the Galaxy (0.7 K) and the Earth's atmosphere (0.8 K) were also significant parts of the data reduction and error analysis. The brightness temperature of the Cosmic Background Radiation at 1.410 GHz is 222. +- 0.55 Kelvin. The spectrum of the CBR, as determined by this measurement and other published results, is consistent with a blackbody spectrum of temperature 2.741 +- 0.016. Constraints on the amount by which the CBR spectrum deviates from Planck spectrum are used to place limits on energy releases early in the history of the universe. 55 refs., 25 figs., 8 tabs.

Levin, S.M.

1987-04-01

19

Upper bounds on the low-frequency stochastic gravitational wave background from pulsar timing observations: current limits and future prospects  

Microsoft Academic Search

Using a statistically rigorous analysis method, we place limits on the\\u000aexistence of an isotropic stochastic gravitational wave background using pulsar\\u000atiming observations. We consider backgrounds whose characteristic strain\\u000aspectra may be described as a power-law dependence with frequency. Such\\u000abackgrounds include an astrophysical background produced by coalescing\\u000asupermassive black-hole binary systems and cosmological backgrounds due to\\u000arelic gravitational waves

F. A. Jenet; G. B. Hobbs; W. van Straten; R. N. Manchester; M. Bailes; J. P. W. Verbiest; R. T. Edwards; A. W. Hotan; J. M. Sarkissian; S. M. Ord

2006-01-01

20

Prepulse Inhibition of Acoustic Startle Reflex as a Function of the Frequency Difference between Prepulse and Background Sounds in Mice  

PubMed Central

Background Prepulse inhibition (PPI) depicts the effects of a weak sound preceding strong acoustic stimulus on acoustic startle response (ASR). Previous studies suggest that PPI is influenced by physical parameters of prepulse sound such as intensity and preceding time. The present study characterizes the impact of prepulse tone frequency on PPI. Methods Seven female C57BL mice were used in the present study. ASR was induced by a 100 dB SPL white noise burst. After assessing the effect of background sounds (white noise and pure tones) on ASR, PPI was tested by using prepulse pure tones with the background tone of either 10 or 18 kHz. The inhibitory effect was assessed by measuring and analyzing the changes in the first peak-to-peak magnitude, root mean square value, duration and latency of the ASR as the function of frequency difference between prepulse and background tones. Results Our data showed that ASR magnitude with pure tone background varied with tone frequency and was smaller than that with white noise background. Prepulse tone systematically reduced ASR as the function of the difference in frequency between prepulse and background tone. The 0.5 kHz difference appeared to be a prerequisite for inducing substantial ASR inhibition. The frequency dependence of PPI was similar under either a 10 or 18 kHz background tone. Conclusion PPI is sensitive to frequency information of the prepulse sound. However, the critical factor is not tone frequency itself, but the frequency difference between the prepulse and background tones.

Basavaraj, Sidhesh; Yan, Jun

2012-01-01

21

Calibration of low-frequency radio telescopes using the galactic background radiation  

NASA Astrophysics Data System (ADS)

We consider the calibration of flux densities of radio bursts from decametric to kilometric wavelengths using ground-based and space-based data. The method we derive is applicable to low-frequency radio telescopes where galactic background radiation is the principal contribution to system temperature. It can be particularly useful for telescopes of low angular resolution observing spectra of radio bursts from the Sun and the planets because absolute calibration of these telescopes is very difficult with conventional techniques. Here we apply the method to observations from about 7 to 47 MHz that were made on the ground with the Bruny Island Radio Spectrometer located in Tasmania, Australia, and those from about 20 kHz to 13.8 MHz were made with the radio experiment WAVES on the WIND spacecraft. The spectrum of the galactic background radiation from <1 to >30 MHz has been carefully measured with low-resolution telescopes, starting more than a decade ago. We use this known spectrum to calibrate both BIRS and WAVES on an absolute scale. The accuracy we achieve is about a factor of two, whereas the flux densities of solar and planetary radio sources vary by many orders of magnitude. Our method permits inter-calibration of ground-based and space-based observations, and allows corrections to be made for instrumental uncertainties on both radio experiments. In addition, on the ground, it allows the spectra to be corrected for ionospheric absorption and partial ground reflections. As an application we show the spectrum of a solar type III burst observed from 47 MHz to 20 kHz. Its flux density was largest, S~ 10-17 W m-2 Hz-1, at about 3 MHz, while at 60 kHz and at 47 MHz it was lower by a factor of about 300.

Dulk, G. A.; Erickson, W. C.; Manning, R.; Bougeret, J.-L.

2001-01-01

22

Efficient induction of Wheat-agropyron cristatum 6P translocation lines and GISH detection.  

PubMed

The narrow genetic background restricts wheat yield and quality improvement. The wild relatives of wheat are the huge gene pools for wheat improvement and can broaden its genetic basis. Production of wheat-alien translocation lines can transfer alien genes to wheat. So it is important to develop an efficient method to induce wheat-alien chromosome translocation. Agropyroncristatum (P genome) carries many potential genes beneficial to disease resistance, stress tolerance and high yield. Chromosome 6P possesses the desirable genes exhibiting good agronomic traits, such as high grain number per spike, powdery mildew resistance and stress tolerance. In this study, the wheat-A. cristatum disomic addition was used as bridge material to produce wheat-A. cristatum translocation lines induced by (60)Co-?irradiation. The results of genomic in situ hybridization showed that 216 plants contained alien chromosome translocation among 571 self-pollinated progenies. The frequency of translocation was 37.83%, much higher than previous reports. Moreover, various alien translocation types were identified. The analysis of M2 showed that 62.5% of intergeneric translocation lines grew normally without losing the translocated chromosomes. The paper reported a high efficient technical method for inducing alien translocation between wheat and Agropyroncristatum. Additionally, these translocation lines will be valuable for not only basic research on genetic balance, interaction and expression of different chromosome segments of wheat and alien species, but also wheat breeding programs to utilize superior agronomic traits and good compensation effect from alien chromosomes. PMID:23874966

Song, Liqiang; Jiang, Lili; Han, Haiming; Gao, Ainong; Yang, Xinming; Li, Lihui; Liu, Weihua

2013-01-01

23

Efficient Induction of Wheat-Agropyron cristatum 6P Translocation Lines and GISH Detection  

PubMed Central

The narrow genetic background restricts wheat yield and quality improvement. The wild relatives of wheat are the huge gene pools for wheat improvement and can broaden its genetic basis. Production of wheat-alien translocation lines can transfer alien genes to wheat. So it is important to develop an efficient method to induce wheat-alien chromosome translocation. Agropyroncristatum (P genome) carries many potential genes beneficial to disease resistance, stress tolerance and high yield. Chromosome 6P possesses the desirable genes exhibiting good agronomic traits, such as high grain number per spike, powdery mildew resistance and stress tolerance. In this study, the wheat-A. cristatum disomic addition was used as bridge material to produce wheat-A. cristatum translocation lines induced by 60Co-?irradiation. The results of genomic in situ hybridization showed that 216 plants contained alien chromosome translocation among 571 self-pollinated progenies. The frequency of translocation was 37.83%, much higher than previous reports. Moreover, various alien translocation types were identified. The analysis of M2 showed that 62.5% of intergeneric translocation lines grew normally without losing the translocated chromosomes. The paper reported a high efficient technical method for inducing alien translocation between wheat and Agropyroncristatum. Additionally, these translocation lines will be valuable for not only basic research on genetic balance, interaction and expression of different chromosome segments of wheat and alien species, but also wheat breeding programs to utilize superior agronomic traits and good compensation effect from alien chromosomes.

Song, Liqiang; Jiang, Lili; Han, Haiming; Gao, Ainong; Yang, Xinming; Li, Lihui; Liu, Weihua

2013-01-01

24

Measuring the background ionic emission of tungsten monocrystals used in quantum frequency standards  

Microsoft Academic Search

1.The main source of ion current spikes in the polycrystalline background emission consists of grain boundaries as the most defective area in the metal.2.Monocrystalline emission is stable over the entire temperature range, and this is due to the absence of grain boundaries and a uniform distribution of admixtures. The noise produced by background emission of the detectors' monocrystalline tapes with

Yu. G. Abashev; N. N. Raskatov; I. V. Chernyshev

1973-01-01

25

Multi-frequency measurements of the NVSS foreground sources in the cosmic background imager fields. I. Data release  

Microsoft Academic Search

Context: We present the results of the flux density measurements at 4.85 GHz and 10.45 GHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope. Aims: The initial motivation was the need to identify the NVSS radio sources that could potentially contribute significant contaminating flux in the frequency range at which the Cosmic Background Imager

E. Angelakis; A. Kraus; A. C. S. Readhead; J. A. Zensus; R. Bustos; T. P. Krichbaum; A. Witzel; T. J. Pearson

2009-01-01

26

Effects of fast-acting high-frequency compression on the intelligibility of speech in steady and fluctuating background sounds.  

PubMed

This study examines whether speech intelligibility in background sounds can be improved for persons with loudness recruitment by the use of fast-acting compression applied at high frequencies, when the overall level of the sounds is held constant by means of a slow-acting automatic gain control (AGC) system and when appropriate frequency-response shaping is applied. Two types of fast-acting compression were used in the high-frequency channel of a two-channel system: a compression limiter with a 10:1 compression ratio and with a compression threshold about 9 dB below the peak level of the signal in the high-frequency channel; and a wide dynamic range compressor with a 2:1 compression ratio and with the compression threshold about 24 dB below the peak level of the signal in the high-frequency channel. A condition with linear processing in the high-frequency channel was also used. Speech reception thresholds (SRTs) were measured for two background sounds: a steady speech-shaped noise and a single male talker. All subjects had moderate-to-severe sensorineural hearing loss. Three different types of speech material were used: the adaptive sentence lists (ASL), the Bamford-Kowal-Bench (BKB) sentence lists and the Boothroyd word lists. For the steady background noise, the compression generally led to poorer performance than for the linear condition, although the deleterious effect was only significant for the 10:1 compression ratio. For the background of a single talker, the compression had no significant effect except for the ASL sentences, where the 10:1 compression gave significantly better performance than the linear condition. Overall, the results did not show any clear benefits of the fast-acting compression, possibly because the slow-acting AGC allowed the use of gains in the linear condition that were markedly higher than would normally be used with linear hearing aids. PMID:9307821

Stone, M A; Moore, B C; Wojtczak, M; Gudgin, E

1997-08-01

27

Production and identification of wheat-Agropyron cristatum 6P translocation lines.  

PubMed

The narrow genetic background of wheat is the primary factor that has restricted the improvement of crop yield in recent years. The kernel number per spike is the most important factor of the many potential characteristics that determine wheat yield. Agropyron cristatum (L.) Gaertn., a wild relative of wheat, has the characteristics of superior numbers of florets and kernels per spike, which are controlled by chromosome 6P. In this study, the wheat-A. cristatum disomic addition and substitution lines were used as bridge materials to produce wheat-A. cristatum 6P translocation lines induced by gametocidal chromosomes and irradiation. The results of genomic in situ hybridization showed that the frequency of translocation induced by gametocidal chromosomes was 5.08%, which was higher than the frequency of irradiated hybrids (2.78%) and irradiated pollen (2.12%). The fluorescence in situ hybridization results of the translocation lines showed that A. cristatum chromosome 6P could be translocated to wheat ABD genome, and the recombination frequency was A genome > B genome > D genome. The alien A. cristatum chromosome 6P was translocated to wheat homoeologous groups 1, 2, 3, 5 and 6. We obtained abundant translocation lines that possessed whole-arm, terminal, segmental and intercalary translocations. Three 6PS-specific and four 6PL-specific markers will be useful to rapidly identify and trace the translocated fragments. The different wheat-A. cristatum 6P translocation lines obtained in this study can provide basic materials for analyzing the alien genes carried by chromosome 6P. The translocation line WAT33-1-3 and introgression lines WAI37-2 and WAI41-1, which had significant characteristics of multikernel (high numbers of kernels per spike), could be utilized as novel germplasms for high-yield wheat breeding. PMID:20490543

Luan, Yang; Wang, Xiaoguang; Liu, Weihua; Li, Chunye; Zhang, Jinpeng; Gao, Ainong; Wang, Yandong; Yang, Xinming; Li, Lihui

2010-07-01

28

Low Frequency measurment of the Spectrum of the Cosmic BackgroundRadiation  

SciTech Connect

We have made measurements of the cosmic background radiation spectrum at 5 wavelengths (0.33, 0.9, 3, 6.3, and 12 cm) using radiometers with wavelength-scaled corrugated horn antennas having very low sidelobes. A single large-mouth (0.7 m diameter) liquid-helium-cooled absolute reference load was used for all five radiometers. The results of the observations are consistent with previous measurements and represent a significant improvement in accuracy.

Smoot, G.F.; De Amici, G.; Friedman, S.D.; Witebsky, C.; Mandolesi, N.; Partridge, R.b.; Sironi, G.; Danese, L.; De Zotti, G.

1983-06-01

29

A study of resonance structures with different frequency scales in the spectrum of background extremely low-frequency noise at middle latitudes  

NASA Astrophysics Data System (ADS)

Using the data of continuous monitoring of low-frequency background noise at the station "Novaya Zhizn" (Nizhny Novgorod Province, Russia) for 2006-2010, we studied a new spectral structure appearing in quasi-harmonic oscillations of the noise intensity with frequency scales a factor of 3 to 4 smaller than the scales of an ordinary spectral resonance structure. The features of the fine spectral structure were studied, i.e., frequency of occurrence, diurnal dynamics, and the frequency bandwidth. The features of an ordinary resonance structure were also studied in the "fine structure" appearance and the transition solar-activity periods (2010-2011). Using the calculations of the low-frequency magnetic fields propagating in a spherically horizontally inhomogeneous Earth-ionosphere waveguide, we analyzed the possible influence of the nonlocal ionospheric properties on the magnetic-component spectra in the range 0.1-20 Hz. It is shown that the influence of the nonlocal ionospheric properties on the extremely low-frequency spectra can be observed in the presence of an ionospheric horizontal inhomogeneity due to different shapes of the ionospheric-parameter profiles along the radio-wave propagation path.

Ermakova, E. N.; Polyakov, S. V.; Semenova, N. V.

2012-05-01

30

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements.  

PubMed

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ?MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors. PMID:22852677

Dobbs, M A; Lueker, M; Aird, K A; Bender, A N; Benson, B A; Bleem, L E; Carlstrom, J E; Chang, C L; Cho, H-M; Clarke, J; Crawford, T M; Crites, A T; Flanigan, D I; de Haan, T; George, E M; Halverson, N W; Holzapfel, W L; Hrubes, J D; Johnson, B R; Joseph, J; Keisler, R; Kennedy, J; Kermish, Z; Lanting, T M; Lee, A T; Leitch, E M; Luong-Van, D; McMahon, J J; Mehl, J; Meyer, S S; Montroy, T E; Padin, S; Plagge, T; Pryke, C; Richards, P L; Ruhl, J E; Schaffer, K K; Schwan, D; Shirokoff, E; Spieler, H G; Staniszewski, Z; Stark, A A; Vanderlinde, K; Vieira, J D; Vu, C; Westbrook, B; Williamson, R

2012-07-01

31

Multi-frequency measurements of the NVSS foreground sources in the Cosmic Background Imager fields. I. Data release  

Microsoft Academic Search

We present the results of the flux density measurements at 4.85 GHz and 10.45\\u000aGHz of a sample of 5998 NVSS radio sources with the Effelsberg 100 m telescope.\\u000aThe initial motivation was the need to identify the NVSS radio sources that\\u000acould potentially contribute significant contaminating flux in the frequency\\u000arange at which the Cosmic Background Imager experiment operated.

E. Angelakis; A. Kraus; A. C. S. Readhead; J. A. Zensus; R. Bustos; T. P. Krichbaum; A. Witzel; T. J. Pearson

2009-01-01

32

Spatial frequency characteristics at image decision-point locations for observers with different radiological backgrounds in lung nodule detection  

NASA Astrophysics Data System (ADS)

Aim: The goal of the study is to determine the spatial frequency characteristics at locations in the image of overt and covert observers' decisions and find out if there are any similarities in different observers' groups: the same radiological experience group or the same accuracy scored level. Background: The radiological task is described as a visual searching decision making procedure involving visual perception and cognitive processing. Humans perceive the world through a number of spatial frequency channels, each sensitive to visual information carried by different spatial frequency ranges and orientations. Recent studies have shown that particular physical properties of local and global image-based elements are correlated with the performance and the level of experience of human observers in breast cancer and lung nodule detections. Neurological findings in visual perception were an inspiration for wavelet applications in vision research because the methodology tries to mimic the brain processing algorithms. Methods: The wavelet approach to the set of postero-anterior chest radiographs analysis has been used to characterize perceptual preferences observers with different levels of experience in the radiological task. Psychophysical methodology has been applied to track eye movements over the image, where particular ROIs related to the observers' fixation clusters has been analysed in the spaces frame by Daubechies functions. Results: Significance differences have been found between the spatial frequency characteristics at the location of different decisions.

Pietrzyk, Mariusz W.; Manning, David J.; Dix, Alan; Donovan, Tim

2009-02-01

33

Array painting reveals a high frequency of balanced translocations in breast cancer cell lines that break in cancer-relevant genes.  

PubMed

Chromosome translocations in the common epithelial cancers are abundant, yet little is known about them. They have been thought to be almost all unbalanced and therefore dismissed as mostly mediating tumour suppressor loss. We present a comprehensive analysis by array painting of the chromosome translocations of breast cancer cell lines HCC1806, HCC1187 and ZR-75-30. In array painting, chromosomes are isolated by flow cytometry, amplified and hybridized to DNA microarrays. A total of 200 breakpoints were identified and all were mapped to 1 Mb resolution on bacterial artificial chromosome (BAC) arrays, then 40 selected breakpoints, including all balanced breakpoints, were further mapped on tiling-path BAC arrays or to around 2 kb resolution using oligonucleotide arrays. Many more of the translocations were balanced at 1 Mb resolution than expected, either reciprocal (eight in total) or balanced for at least one participating chromosome (19 paired breakpoints). Second, many of the breakpoints were at genes that are plausible targets of oncogenic translocation, including balanced breaks at CTCF, EP300/p300 and FOXP4. Two gene fusions were demonstrated, TAX1BP1-AHCY and RIF1-PKD1L1. Our results support the idea that chromosome rearrangements may play an important role in common epithelial cancers such as breast cancer. PMID:18084325

Howarth, K D; Blood, K A; Ng, B L; Beavis, J C; Chua, Y; Cooke, S L; Raby, S; Ichimura, K; Collins, V P; Carter, N P; Edwards, P A W

2008-05-22

34

Array painting reveals a high frequency of balanced translocations in breast cancer cell lines that break in cancer-relevant genes  

PubMed Central

Chromosome translocations in the common epithelial cancers are abundant, yet little is known about them. They have been thought to be almost all unbalanced and therefore dismissed as mostly mediating tumour suppressor loss. We present a comprehensive analysis by array painting of the chromosome translocations of breast cancer cell lines HCC1806, HCC1187 and ZR-75-30. In array painting, chromosomes are isolated by flow cytometry, amplified and hybridized to DNA microarrays. A total of 200 breakpoints were identified and all were mapped to 1Mb resolution on BAC arrays, then 40 selected breakpoints, including all balanced breakpoints, were further mapped on tiling-path BAC arrays or to around 2kb resolution using oligonucleotide arrays. Many more of the translocations were balanced at 1Mb resolution than expected, either reciprocal (eight in total) or balanced for at least one participating chromosome (19 paired breakpoints). Secondly, many of the breakpoints were at genes that are plausible targets of oncogenic translocation, including balanced breaks at CTCF, EP300/p300, and FOXP4. Two gene fusions were demonstrated, TAX1BP1-AHCY and RIF1-PKD1L1. Our results support the idea that chromosome rearrangements may play an important role in common epithelial cancers such as breast cancer.

Howarth, KD; Blood, KA; Ng, BL; Beavis, JC; Chua, Y; Cooke, SL; Raby, S; Ichimura, K; Collins, VP; Carter, NP; Edwards, PAW

2008-01-01

35

A Measurement of the Temperature of the Cosmic MicrowaveBackground at a Frequency of 7.5 GHz  

SciTech Connect

We have measured the intensity of the cosmic microwave background (CMB) at a frequency of 7.5 GHz (wavelength 4.0 cm) using a ground-based, total power radiometer calibrated at the horn aperture by an external cryogenic reference target. The radiometer measured the difference in antenna temperature between the reference target and the zenith sky from a dry, high-altitude site. Subtraction of foreground signals (primarily atmospheric and galactic emission) measured with the same instrument leaves the CMB as the residual. The radiometer measured the atmospheric antenna temperature by correlating the signal change with the airmass in the beam during tip scans. The small galactic signal was subtracted based on extrapolation from lower frequencies, and was checked by differential drift scans. The limiting uncertainty in the CMB measurement was the effect of ground radiation in the antenna sidelobes during atmospheric measurements. The thermodynamic temperature of the CMB at 7.5 GHz is 2.59 {+-} 0.07 K (68% confidence level).

Kogut, A.; Bensadoun, M.; De Amici, Giovanni; Levin, S.; Smoot,George F.; Witebsky, C.

1989-06-01

36

The Pontin series of recombinant alien translocations in bread wheat: single translocations integrating combinations of Bdv2, Lr19 and Sr25 disease-resistance genes from Thinopyrum intermedium and Th. ponticum.  

PubMed

Two bread wheat lines each with a translocation on chromosome 7DL from either Thinopyrum intermedium (TC5 and TC14) or Thinopyrum ponticum (T4m), were hybridized in a ph1b mutant background to enhance recombination between the two translocated chromosomal segments. The frequency of recombinants was high in lines derived from the larger and similar-sized translocations (TC5/T4m), but much lower when derived from different-sized translocations (TC14/T4m). Recombinant translocations contained combinations of resistance genes Bdv2, Lr19 and Sr25 conferring resistance to Barley yellow dwarf virus (BYDV), leaf rust and stem rust, respectively. Their genetic composition was identified using bioassays and molecular markers specific for the two progenitor Thinopyrum species. This set of 7DL Th. ponticum/intermedium recombinant translocations was termed the Pontin series. In addition to Thinopyrum markers, the size of the translocation was estimated with the aid of wheat markers mapped on each of the 7DL deletion bins. Bioassays for BYDV, leaf rust and stem rust were performed under greenhouse and field conditions. Once separated from ph1b background, the Pontin recombinant translocations were stable and showed normal inheritance in successive backcrosses. The reported Pontin translocations integrate important resistance genes in a single linkage block which will allow simultaneous selection of disease resistance. Combinations of Bdv2 + Lr19 or Lr19 + Sr25 in both long and short translocations, are available to date. The smaller Pontins, comprising only 20 % of the distal portion of 7DL, will be most attractive to breeders. PMID:23807636

Ayala-Navarrete, L I; Mechanicos, A A; Gibson, J M; Singh, D; Bariana, H S; Fletcher, J; Shorter, S; Larkin, Philip J

2013-10-01

37

Different Frequency in the Recovery of Crossover Products from Male and Female Gametes of Plants Hypoploid for B-a Translocations in Maize  

PubMed Central

The percentage of crossovers is consistently higher in plants hypoploid for six B-A translocations when crossed as males than when crossed as females; in most instances, this excess of male crossing over exceeds that found in control crosses (involving normal chromosomes). Thus, there seems to be something about the hypoploid condition that is responsible for the higher percentage of male crossovers. Several explanations for this "hypoploid effect" are possible, but none has been demonstrated to be responsible for the phenomenon.

Robertson, D. S.

1984-01-01

38

Low frequency association of the t(2;5)(p23;q35) chromosomal translocation with CD30+ lymphomas from American and Asian patients. A reverse transcriptase-polymerase chain reaction study.  

PubMed Central

Although cytogenetic data suggest that the t(2;5)-(p23;q35) translocation occurs in many cases of CD30+ lymphomas, the exact frequency of this event is still unknown. To clarify this issue and its epidemiological characteristics, we examined 37 formalin-fixed, paraffin-embedded specimens of CD30+ lymphomas from the United States and Hong Kong by reverse transcriptase-polymerase chain reaction (RT-PCR) for the status of the NPM and ALK genes, which are typically juxtaposed by the t(2;5) translocation. Thirty-four cases were classified as anaplastic large cell lymphomas (ALCL), 2 cases as non-anaplastic large cell lymphomas (LCL), and 1 case as the small cell variant of CD30+ lymphoma. The t(2;5) translocation was detected in 6 cases (16%), including 3 of 18 American patients and 3 of 19 cases from Hong Kong. All cases had a 185-bp NPM RT-PCR product as detected by Southern blot analysis, indicating adequate preservation of mRNA. The 6 positive cases were among 4 of 34 adult lymphomas, as compared with 2 of 3 childhood cases. Five of 17 T-lineage cases were t(2;5)-positive, compared with 1 of 15 B-lineage cases and none of the 5 null-cell or mixed lineage cases. Our results therefore show that t(2;5) occurs at a low frequency among CD30+ lymphomas, at least in our adult-dominated series. Images Figure 1 Figure 2

Lopategui, J. R.; Sun, L. H.; Chan, J. K.; Gaffey, M. J.; Frierson, H. F.; Glackin, C.; Weiss, L. M.

1995-01-01

39

Production and identification of wheat - Agropyron cristatum (1.4P) alien translocation lines.  

PubMed

The P genome of Agropyron Gaertn., a wild relative of wheat, contains an abundance of desirable genes that can be utilized as genetic resources to improve wheat. In this study, wheat - Aegilops cylindrica Host gametocidal chromosome 2C addition lines were crossed with wheat - Agropyron cristatum (L.) Gaertn. disomic addition line accession II-21 with alien recombinant chromosome (1.4)P. We successfully induced wheat - A. cristatum alien chromosomal translocations for the first time. The frequency of translocation in the progeny was 3.75%, which was detected by molecular markers and genomic in situ hybridization (GISH). The translocation chromosomes were identified by dual-color GISH /fluorescence in situ hybridization (FISH). The P genomic DNA was used as probe to detect the (1.4)P chromosome fragment, and pHvG39, pAs1, or pSc119.2 repeated sequences were used as probes to identify wheat translocated chromosomes. The results showed that six types of translocations were identified in the three wheat - A. cristatum alien translocation lines, including the whole arm or terminal portion of a (1.4)P chromosome. The (1.4)P chromosome fragments were translocated to wheat chromosomes 1B, 2B, 5B, and 3D. The breakpoints were located at the centromeres of 1B and 2B, the pericentric locations of 5BS, and the terminals of 5BL and 3DS. In addition, we obtained 12 addition-deletion lines that contained alien A. cristatum chromosome (1.4)P in wheat background. All of these wheat - A. cristatum alien translocation lines and addition-deletion lines would be valuable for identifying A. cristatum chromosome (1.4)P-related genes and providing genetic resources and new germplasm accessions for the genetic improvement of wheat. The specific molecular markers of A. cristatum (1.4)P chromosome have been developed and used to track the (1.4)P chromatin. PMID:20555436

Liu, Wei-Hua; Luan, Yang; Wang, Jing-Chang; Wang, Xiao-Guang; Su, Jun-Ji; Zhang, Jin-Peng; Yang, Xin-Ming; Gao, Ai-Nong; Li, Li-Hui

2010-06-01

40

Theoretical background for continental- and global-scale full-waveform inversion in the time-frequency domain  

Microsoft Academic Search

We propose a new approach to full seismic waveform inversion on continental and global scales. This is based on the time-frequency transform of both data and synthetic seismograms with the use of time- and frequency-dependent phase and envelope misfits. These misfits allow us to provide a complete quantification of the differences between data and synthetics while separating phase and amplitude

Andreas Fichtner; Brian L. N. Kennett; Heiner Igel; Hans-Peter Bunge

2008-01-01

41

Counterrotation of the globe in macular translocation  

Microsoft Academic Search

Background: Macular translocation is a new treatment option in age-related maculopathy. The aim of this study was to report experience\\u000a with the handling of the sensory problems concerning subjective cyclorotation and binocularity that arise with this technique.\\u000a Methods: The data of 33 patients who had undergone macular translocation and counterrotation of the globe by muscle surgery in a first\\u000a operation,

Julia Fricke; Antje Neugebauer; Heike Nobis; Karl U. Bartz-Schmidt; W. Rüßmann

2000-01-01

42

Analysis of Chromosomal Translocations  

Microsoft Academic Search

\\u000a Chromosomal translocations were the first target for the specific detection of residual tumor cells in bone marrow and peripheral\\u000a blood. Some types of leukemia are regularly or generally associated with translocations. In chronic myelogenous leukemia (CML)\\u000a and a proportion of patients with acute lymphoblastic leukemia (ALL), the t(9;22)(q34;q11) translocation leads to the fusion\\u000a of the ABL gene with part of

Andreas Hochhaus

43

Relative contribution of off- and on-frequency spectral components of background noise to the masking of unprocessed and vocoded speech  

PubMed Central

The present study examined the relative influence of the off- and on-frequency spectral components of modulated and unmodulated maskers on consonant recognition. Stimuli were divided into 30 contiguous equivalent rectangular bandwidths. The temporal fine structure (TFS) in each “target” band was either left intact or replaced with tones using vocoder processing. Recognition scores for 10, 15 and 20 target bands randomly located in frequency were obtained in quiet and in the presence of all 30 masker bands, only the off-frequency masker bands, or only the on-frequency masker bands. The amount of masking produced by the on-frequency bands was generally comparable to that produced by the broadband masker. However, the difference between these two conditions was often significant, indicating an influence of the off-frequency masker bands, likely through modulation interference or spectral restoration. Although vocoder processing systematically lead to poorer consonant recognition scores, the deficit observed in noise could often be attributed to that observed in quiet. These data indicate that (i) speech recognition is affected by the off-frequency components of the background and (ii) the nature of the target TFS does not systematically affect speech recognition in noise, especially when energetic masking and?or the number of target bands is limited.

Apoux, Frederic; Healy, Eric W.

2010-01-01

44

The adult polyglucosan body disease mutation GBE1 c.1076A>C occurs at high frequency in persons of Ashkenazi Jewish background.  

PubMed

Mutations of the glycogen branching enzyme gene, GBE1, result in glycogen storage disease (GSD) type IV, an autosomal recessive disorder having multiple clinical forms. One mutant allele of this gene, GBE1 c.1076A>C, has been reported in Ashkenazi Jewish cases of an adult-onset form of GSD type IV, adult polyglucosan body disease (APBD), but no epidemiological analyses of this mutation have been performed. We report here the first epidemiological study of this mutation in persons of Ashkenazi Jewish background and find that this mutation has a gene frequency of 1 in 34.5 (95% CI: 0.0145-0.0512), similar to the frequency of the common mutation causing Tay-Sachs disease among Ashkenazi Jews. This finding reveals APBD to be another monogenic disorder that occurs with increased frequency in persons of Ashkenazi Jewish ancestry. PMID:22943850

Hussain, Abrar; Armistead, Joy; Gushulak, Lara; Kruck, Christa; Pind, Steven; Triggs-Raine, Barbara; Natowicz, Marvin R

2012-09-21

45

Theoretical background for continental- and global-scale full-waveform inversion in the time-frequency domain  

NASA Astrophysics Data System (ADS)

We propose a new approach to full seismic waveform inversion on continental and global scales. This is based on the time-frequency transform of both data and synthetic seismograms with the use of time- and frequency-dependent phase and envelope misfits. These misfits allow us to provide a complete quantification of the differences between data and synthetics while separating phase and amplitude information. The result is an efficient exploitation of waveform information that is robust and quasi-linearly related to Earth's structure. Thus, the phase and envelope misfits are usable for continental- and global-scale tomography, that is, in a scenario where the seismic wavefield is spatially undersampled and where a 3-D reference model is usually unavailable. Body waves, surface waves and interfering phases are naturally included in the analysis. We discuss and illustrate technical details of phase measurements such as the treatment of phase jumps and instability in the case of small amplitudes. The Fréchet kernels for phase and envelope misfits can be expressed in terms of their corresponding adjoint wavefields and the forward wavefield. The adjoint wavefields are uniquely determined by their respective adjoint-source time functions. We derive the adjoint-source time functions for phase and envelope misfits. The adjoint sources can be expressed as inverse time-frequency transforms of a weighted phase difference or a weighted envelope difference. In a comparative study, we establish connections between the phase and envelope misfits and the following widely used measures of seismic waveform differences: (1) cross-correlation time-shifts; (2) relative rms amplitude differences; (3) generalized seismological data functionals and (4) the L2 distance between data and synthetics used in time-domain full-waveform inversion. We illustrate the computation of Fréchet kernels for phase and envelope misfits with data from an event in the West Irian region of Indonesia, recorded on the Australian continent. The synthetic seismograms are computed for a heterogeneous 3-D velocity model of the Australian upper mantle, with a spectral-element method. The examples include P body waves, Rayleigh waves and S waves, interfering with higher-mode surface waves. All the kernels differ from the more familar kernels for cross-correlation time-shifts or relative rms amplitude differences. The differences arise from interference effects, 3-D Earth's structure and waveform dissimilarities that are due to waveform dispersion in the heterogeneous Earth.

Fichtner, Andreas; Kennett, Brian L. N.; Igel, Heiner; Bunge, Hans-Peter

2008-11-01

46

Computational and theoretical insights into protein and peptide translocation.  

PubMed

Biological processes such as protein degradation and mitochondrial protein import require protein passage, or translocation, across narrow pores. In addition to its biological significance, protein translocation through biological or engineered nanopores offers a powerful analytic tool for biophysics and nanotechnology. This mini-review discusses the physical mechanisms of protein translocation, as revealed by computational and theoretical studies. A simple, simulation-based model of translocation is presented, which provides a comprehensive description of this process and allows one to estimate experimentally observable quantities such as the dwell time of a protein inside the pore and the frequency of translocation events. Limitations of this model are further described and possible strategies to overcome them are outlined. Recent simulation studies are beginning to provide insights into the physical mechanisms that drive protein translocation in living systems, which are also discussed here. PMID:24370258

Makarov, Dmitrii E

2014-03-01

47

X-autosome translocations in amenorrhoea: a report of a three way translocation from Indian population.  

PubMed

Chromosomal translocations have been reported in a number of women undergoing cytogenetic studies for amenorrhoea and gonadal dysgenesis. This study was taken up to emphasize the role of X chromosome and to know the frequency of X-autosomal translocations in women with amenorrhoea in Indian population. Cytogenetic analysis was carried out in 1567 subjects referred for amenorrhoea during the period 2002-2012. GTG-banding was performed from peripheral blood lymphocyte cultures to detect the chromosome abnormalities in all the cases. The karyotype results revealed 43.6% cases with chromosomal abnormalities (n?=?683 of 1567 cases). The X-autosomal translocations was found in 2.64% (n?=?18 of 683 cases). The common chromosomes involved with X were chromosomes 2, 4, 14 and 20. The translocations involved both p and q arms of the X chromosome.The break point "q26" of X was observed in the majority of the cases. Two interesting cases are discussed: one with three way translocation and another with two translocations. A high number of primary amenorrhoea (PA) and secondary amenorrhoea (SA) cases were involved in X-auto translocation which clearly reveals that chromosomal analysis plays an important role in the evaluation of amenorrhoea. PMID:24456032

Shetty, Dhanlaxmi L; Kadam, Akshay P; Koppaka, Neeraja T; Dalvi, Rupa C; Chavan, Deepak S; Das, Bibu R; Mandava, Swarna

2014-04-01

48

Two-photon interference using background-free quantum frequency conversion of single photons emitted by an InAs quantum dot.  

PubMed

We show that quantum frequency conversion (QFC) can overcome the spectral distinguishability common to inhomogeneously broadened solid-state quantum emitters. QFC is implemented by combining single photons from an InAs/GaAs quantum dot (QD) at 980 nm with a 1550 nm pump laser in a periodically poled lithium niobate (PPLN) waveguide to generate photons at 600 nm with a signal-to-background ratio exceeding 100:1. Photon correlation and two-photon interference measurements confirm that both the single photon character and wave packet interference of individual QD states are preserved during frequency conversion. Finally, we convert two spectrally separate QD transitions to the same wavelength in a single PPLN waveguide and show that the resulting field exhibits nonclassical two-photon interference. PMID:23083286

Ates, Serkan; Agha, Imad; Gulinatti, Angelo; Rech, Ivan; Rakher, Matthew T; Badolato, Antonio; Srinivasan, Kartik

2012-10-01

49

International study of factors affecting human chromosome translocations  

PubMed Central

Chromosome translocations in peripheral blood lymphocytes of normal, healthy humans increase with age, but the effects of gender, race, and cigarette smoking on background translocation yields have not been examined systematically. Further, the shape of the relationship between age and translocation frequency (TF) has not been definitively determined. We collected existing data from sixteen laboratories in North America, Europe, and Asia on TFs measured in peripheral blood lymphocytes by fluorescence in situ hybridization whole chromosome painting among 1933 individuals. In Poisson regression models, age, ranging from newborns (cord blood) to 85 years, was strongly associated with TF and this relationship showed significant upward curvature at older ages vs. a linear relationship (p <0.001). Ever smokers had significantly higher TFs than non-smokers (rate ratio (RR) = 1.19, 95% confidence interval (CI), 1.09–1.30) and smoking modified the effect of age on TFs with a steeper age-related increase among ever smokers compared to non-smokers (p<0.001). TFs did not differ by gender. Interpreting an independent effect of race was difficult owing to laboratory variation. Our study is three times larger than any pooled effort to date, confirming a suspected curvilinear relationship of TF with age. The significant effect of cigarette smoking has not been observed with previous pooled studies of TF in humans. Our data provide stable estimates of background TF by age, gender, race, and smoking status and suggest an acceleration of chromosome damage above age 60 and among those with a history of smoking cigarettes.

Sigurdson, Alice J.; Ha, Mina; Hauptmann, Michael; Bhatti, Parveen; Sram, Radim J.; Beskid, Olena; Tawn, E. Janet; Whitehouse, Caroline A.; Lindholm, Carita; Nakano, Mimako; Kodama, Yoshiaki; Nakamura, Nori; Vorobtsova, Irena; Oestreicher, Ursula; Stephan, Gunther; Yong, Lee C.; Bauchinger, Manfred; Schmid, Ernst; Chung, Hai Won; Darroudi, Firouz; Roy, Laurence; Voisin, Phillipe; Barquinero, Joan F.; Livingston, Gordon; Blakey, David; Hayata, Isamu; Zhang, Wei; Wang, Chunyan; Bennett, L. Michelle; Littlefield, L. Gayle; Edwards, Alan A.; Kleinerman, Ruth A.; Tucker, James D.

2009-01-01

50

Molecular analysis of nondisjunction in mice heterozygous for a Robertsonian translocation.  

PubMed Central

A Robertsonian translocation results in a metacentric chromosome produced by the fusion of two acrocentric chromosomes. Rb heterozygous mice frequently generate aneuploid gametes and embryos, providing a good model for studying meiotic nondisjunction. We intercrossed mice heterozygous for a (7.18) Robertsonian translocation and performed molecular genotyping of 1812 embryos from 364 litters with known parental origin, strain, and age. Nondisjunction events were scored and factors influencing the frequency of nondisjunction involving chromosomes 7 and 18 were examined. We concluded the following: 1. The frequency of nondisjunction among 1784 embryos (3568 meioses) was 15.9%. 2. Nondisjunction events were distributed nonrandomly among progeny. This was inferred from the distribution of the frequency of trisomics and uniparental disomics (UPDs) among all litters. 3. There was no evidence to show an effect of maternal or paternal age on the frequency of nondisjunction. 4. Strain background did not play an appreciable role in nondisjunction frequency. 5. The frequency of nondisjunction for chromosome 18 was significantly higher than that for chromosome 7 in males. 6. The frequency of nondisjunction for chromosome 7 was significantly higher in females than in males. These results show that molecular genotyping provides a valuable tool for understanding factors influencing meiotic nondisjunction in mammals.

Underkoffler, Lara A; Mitchell, Laura E; Localio, A Russell; Marchegiani, Shannon M; Morabito, Justin; Collins, Joelle N; Oakey, Rebecca J

2002-01-01

51

From spermatocytes to sperm: meiotic behaviour of human male reciprocal translocations  

Microsoft Academic Search

BACKGROUND: Human male translocation carriers may present alterations in the meiotic process due to the presence of the translocated chromosomes. The aim of this work was to study the mechanisms that affect meiotic segregation in translocation carriers by analysing different stages of the meiotic process. METHODS: Meiotic studies using fluorescence in-situ hybridization on both spermatocytes and sperm nuclei were performed

M. Oliver-Bonet; J. Navarro; M. Codina-Pascual; C. Abad; M. Guitart; J. Egozcue; J. Benet

2004-01-01

52

Translocated effectors of Yersinia  

PubMed Central

Summary Currently, all known translocated effectors of Yersinia are delivered into host cells by type III secretion systems (T3SSs). Pathogenic Yersinia maintain the plasmid-encoded Ysc T3SS for the specific delivery of the well-studied Yop effectors. New horizons for effector biology have opened with the discovery of the Ysps of Y. enterocolitica Biovar 1B, which are translocated into host cells by the chromosome-endoded Ysa T3SS. The reported arsenal of effectors is likely to expand since genomic analysis has revealed gene-clusters in some Yersinia that code for other T3SSs. These efforts also revealed possible type VI secretion (T6S) systems, which may indicate translocation of effectors occurs by multiple mechanisms.

Matsumoto, Hiroyuki; Young, Glenn M.

2009-01-01

53

Problem-Elephant Translocation: Translocating the Problem and the Elephant?  

PubMed Central

Human-elephant conflict (HEC) threatens the survival of endangered Asian elephants (Elephas maximus). Translocating “problem-elephants” is an important HEC mitigation and elephant conservation strategy across elephant range, with hundreds translocated annually. In the first comprehensive assessment of elephant translocation, we monitored 16 translocations in Sri Lanka with GPS collars. All translocated elephants were released into national parks. Two were killed within the parks where they were released, while all the others left those parks. Translocated elephants showed variable responses: “homers” returned to the capture site, “wanderers” ranged widely, and “settlers” established home ranges in new areas soon after release. Translocation caused wider propagation and intensification of HEC, and increased elephant mortality. We conclude that translocation defeats both HEC mitigation and elephant conservation goals.

Fernando, Prithiviraj; Leimgruber, Peter; Prasad, Tharaka; Pastorini, Jennifer

2012-01-01

54

Structural differences in reciprocal translocations  

Microsoft Academic Search

Interchange segment sizes and the sizes of chromosome imbalance arising from the different modes of meiotic segregation were measured in a selected sample of 20 reciprocal translocations (Rcp). The Rcp were selected by two modes of ascertainment: (I) neonates with an unbalanced form of the translocation, and (II) couples with recurrent spontaneous abortions without evidence of full-term translocation aneuploid offspring.

A. Daniel

1979-01-01

55

Protein Translocation Across Biological Membranes  

NSDL National Science Digital Library

This article provides a review of progress made in the study of protein translocation. Subcellular compartments have unique protein compositions, yet protein synthesis only occurs in the cytosol and in mitochondria and chloroplasts. How do proteins get where they need to go? The first steps are targeting to an organelle and efficient translocation across its limiting membrane. Given that most transport systems are exquisitely substrate specific, how are diverse protein sequences recognized for translocation? Are they translocated as linear polypeptide chains or after folding? During translocation, how are diverse amino acyl side chains accommodated? What are the proteins and the lipid environment that catalyze transport and couple it to energy? How is translocation coordinated with protein synthesis and folding, and how are partially translocated transmembrane proteins released into the lipid bilayer? We review here the marked progress of the past 35 years and salient questions for future work.

William Wickner (Dartmouth Medical School;Department of Biological Chemistry); Randy Schekman (University of California;Howard Hughes Medical Institute and Department of Molecular and Cell Biology)

2005-12-02

56

Causes of oncogenic chromosomal translocation  

PubMed Central

Non-random chromosomal translocations are frequently associated with a variety of cancers, especially hematologic malignancies and childhood sarcomas In addition to their diagnostic utility, chromosomal translocations are increasingly being used in the clinic to guide therapeutic decisions. However, the mechanisms which cause these translocations remain poorly understood. Illegitimate V(D)J recombination, class switch recombination, homologous recombination, non-homologous end joining, and genome fragile sites all have potential roles in the production of non-random chromosomal translocations. In addition, mutations in DNA repair pathways have been implicated in the production of chromosomal translocations in humans, mice, and yeast. Although initially quite surprising, the identification of these same oncogenic chromosomal translocations in peripheral blood from healthy individuals strongly suggests that the translocation is not sufficient to induce malignant transformation, and that complementary mutations are required to produce a frank malignancy.

Aplan, Peter D.

2006-01-01

57

Clinical significance of translocation.  

PubMed Central

The gastrointestinal tract, besides being the organ responsible for nutrient absorption, is also a metabolic and immunological system, functioning as an effective barrier against endotoxin and bacteria in the intestinal lumen. The passage of viable bacteria from the gastrointestinal tract through the epithelial mucosa is called bacterial translocation. Equally important may be the passage of bacterial endotoxin through the mucosal barrier. This article reviews the evidence that translocation of both endotoxin and bacteria is of clinical significance. It summarises recent published works indicating that translocation of endotoxin in minute amounts is a physiological important phenomenon to boost the reticuloendothelial system (RES), especially the Kupffer cells, in the liver. Breakdown of both the mucosal barrier and the RES capacity results in systemic endotoxaemia. Systemic endotoxaemia results in organ dysfunction, impairs the mucosal barrier, the clotting system, the immune system, and depresses Kupffer cell function. If natural defence mechanisms such as lipopolysaccharide binding protein, high density lipoprotein, in combination with the RES, do not respond properly, dysfunction of the gut barrier results in bacterial translocation. Extensive work on bacterial translocation has been performed in animal models and occurs notably in haemorrhagic shock, thermal injury, protein malnutrition, endotoxaemia, trauma, and intestinal obstruction. It is difficult to extrapolate these results to humans and its clinical significance is not clear. The available data show that the resultant infection remains important in the development of sepsis, especially in the critically ill patient. Uncontrolled infection is, however, neither necessary nor sufficient to account for the development of multiple organ failure. A more plausible sequelae is that bacterial translocation is a later phenomenon of multiple organ failure, and not its initiator. It is hypothesized that multiple organ failure is more probably triggered by the combination of tissue damage and systemic endotoxaemia. Endotoxaemia, as seen in trauma patients especially during the first 24 hours, in combination with tissue elicits a systemic inflammation, called Schwartzmann reaction. Interferon gamma, a T cell produced cytokine, is thought to play a pivotal part in the pathogenesis of this reaction. This reaction might occur only if the endotoxin induced cytokines like tumour necrosis factor and interleukin 1, act on target cells prepared by interferon gamma. After exposure to interferon gamma target cells become more sensitive to stimuli like endotoxin, thus boosting the inflammatory cycle. Clearly, following this line of reasoning, minor tissue damage or retroperitoneal haematoma combined with systemic endotoxaemia could elicit this reaction. The clinically observed failure of multiple organ systems might thus be explained by the interaction of tissue necrosis and high concentrations of endotoxin because of translocation. Future therapeutic strategies could therefore focus more on binding endotoxin in the gut before the triggering event, for example before major surgery. Such a strategy could be combined with the start of early enteral feeding, which has been shown in animal studies to have a beneficial effect on intestinal mucosal barrier function and in traumatized patients to reduce the incidence of septic complications.

Van Leeuwen, P A; Boermeester, M A; Houdijk, A P; Ferwerda, C C; Cuesta, M A; Meyer, S; Wesdorp, R I

1994-01-01

58

Foliar Absorption and Phloem Translocation  

NSDL National Science Digital Library

Herbicides must be absorbed into plants in order to be effective. Herbicide absorption can occur through leaves, roots or both. The process by which herbicides kill weeds, called mode of action, requires herbicide absorption and may also require herbicide movement or translocation within the plant. Translocation means that the herbicide moves from the site of absorption to some other plant part. Foliar applied herbicides that have the necessary characteristics to move in the phloem will translocate to areas of the plant that are actively growing; however, not all foliar-applied herbicides move from the leaves that intercepted the spray solution. Herbicides that are absorbed but not translocated are calledcontact herbicides, while herbicides that translocate to shoot or root meristems are called systemic herbicides. Absorption and translocation of xylem mobile herbicides will be discussed in another lesson.

59

Translocations in epithelial cancers  

PubMed Central

Genomic translocations leading to the expression of chimeric transcripts characterize several hematologic, mesenchymal and epithelial malignancies. While several gene fusions have been linked to essential molecular events in hematologic malignancies, the identification and characterization of recurrent chimeric transcripts in epithelial cancers has been limited. However, the recent discovery of the recurrent gene fusions in prostate cancer has sparked a revitalization of the quest to identify novel rearrangements in epithelial malignancies. Here, the molecular mechanisms of gene fusions that drive several epithelial cancers and the recent technological advances that increase the speed and reliability of recurrent gene fusion discovery are explored.

Chad Brenner, J.; Chinnaiyan, Arul M.

2009-01-01

60

Reciprocal translocations in Saccharomyces cerevisiae formed by nonhomologous end joining.  

PubMed Central

Reciprocal translocations are common in cancer cells, but their creation is poorly understood. We have developed an assay system in Saccharomyces cerevisiae to study reciprocal translocation formation in the absence of homology. We induce two specific double-strand breaks (DSBs) simultaneously on separate chromosomes with HO endonuclease and analyze the subsequent chromosomal rearrangements among surviving cells. Under these conditions, reciprocal translocations via nonhomologous end joining (NHEJ) occur at frequencies of approximately 2-7 x 10(-5)/cell exposed to the DSBs. Yku80p is a component of the cell's NHEJ machinery. In its absence, reciprocal translocations still occur, but the junctions are associated with deletions and extended overlapping sequences. After induction of a single DSB, translocations and inversions are recovered in wild-type and rad52 strains. In these rearrangements, a nonrandom assortment of sites have fused to the DSB, and their junctions show typical signs of NHEJ. The sites tend to be between open reading frames or within Ty1 LTRs. In some cases the translocation partner is formed by a break at a cryptic HO recognition site. Our results demonstrate that NHEJ-mediated reciprocal translocations can form in S. cerevisiae as a consequence of DSB repair.

Yu, Xin; Gabriel, Abram

2004-01-01

61

Multi-frequency polarimetry of the Galactic radio background around 350 MHz. I. A region in Auriga around l = 161 deg, b = 16 deg  

NASA Astrophysics Data System (ADS)

With the Westerbork Synthesis Radio Telescope (WSRT), multi-frequency polarimetric images were taken of the diffuse radio synchrotron background in a ~ 5 deg times 7 deg region centered on (l,b) = (161 deg ,16 deg ) in the constellation of Auriga. The observations were done simultaneously in 5 frequency bands, from 341 MHz to 375 MHz, and have a resolution of ~ 5.0arcminx5 .0arcmin cosec delta . The polarized intensity P and polarization angle phi show ubiquitous structure on arcminute and degree scales, with polarized brightness temperatures up to about 13 K. On the other hand, no structure at all is observed in total intensity I to an rms limit of 1.3 K, indicating that the structure in the polarized radiation must be due to Faraday rotation and depolarization mostly in the warm component of the nearby Galactic interstellar medium (ISM). Different depolarization processes create structure in polarized intensity P. Beam depolarization creates ``depolarization canals'' of one beam wide, while depth depolarization is thought to be responsible for creating most of the structure on scales larger than a beam width. Rotation measures (RM) can be reliably determined, and are in the range -17 <~ RM <~ 10 rad m-2 with a non-zero average RM0 ~ -3.4 rad m-2. The distribution of RMs on the sky shows both abrupt changes on the scales of the beam and a gradient in the direction of positive Galactic longitude of ~ 1 rad m-2 per degree. The gradient and average RM are consistent with a regular magnetic field of ~ 1 mu G which has a pitch angle of p = -14 deg. There are 13 extragalactic sources in the field for which RMs could be derived, and those have |RM| <~ 13 rad m-2, with an estimated intrinsic source contribution of ~ 3.6 rad m-2. The RMs of the extragalactic sources show a gradient that is about 3 times larger than the gradient in the RMs of the diffuse emission and that is approximately in Galactic latitude. This difference is ascribed to a vastly different effective length of the line of sight. The RMs of the extragalactic sources also show a sign reversal which implies a reversal of the magnetic field across the region on scales larger than about ten degrees. The observations are interpreted in terms of a simple single-cell-size model of the warm ISM which contains gas and magnetic fields, with a polarized background. The observations are best fitted with a cell size of 10 to 20 pc and a ratio of random to regular magnetic fields Bran/Breg ~ 0.7+/-0.5. The polarization horizon, beyond which most diffuse polarized emission is depolarized, is estimated to be at a distance of about 600 pc.

Haverkorn, M.; Katgert, P.; de Bruyn, A. G.

2003-06-01

62

Polymer translocation facilitated by Chaperones  

NASA Astrophysics Data System (ADS)

We study translocation of biopolymers through a nanopore in a membrane facilitated by attractive binding particles (Chaperones) using Langevin dynamics simulation. Specifically we study how the density and attractive strength of these bindings particles affect the chain conformations at the trans side and mean first passage time (MFPT). We also consider model larger chaperone that can bind reversibly on the multiple units of the translocating chain. Finally, we consider translocation of heteropolymers and how a specific sequence affect the translocation process. We discuss relevance of our studies in biological translocation processes.^1R. Zandi, D. Reguera, J. Rudnick and W. M. Gelbart, Proc. Natl. Acad. Sci. USA 100 8649 (2003).^2W. Sung and P. J. Park, Phys. Rev. Lett. 77, 783 (1996).

Bhattacharya, Aniket; Ala-Nissila, Tapio; Sung, Wokyung

2011-03-01

63

Macromolecular mechanisms of protein translocation.  

PubMed

When macromolecules such as proteins are forced to translocate through a narrow pore, their conformational entropy is reduced, resulting in a free energy barrier. This free energy barrier is additionally modulated by protein-pore interactions. Furthermore, the driving force of the translocation such as the electrochemical potential gradient and electroosmotic flow navigates the transport of the protein through the free energy landscape. Depending on the specifics of the protein-pore system and the driving force, the details of the translocation process and their statistical properties such as the average translocation time can vary significantly. Nevertheless, there are a few fundamental physical concepts that underly the ubiquitous phenomenon of polymer translocation, which are reviewed here. PMID:24370256

Muthukumar, M

2014-03-01

64

The translocator protein.  

PubMed

The translocator protein (TSPO) is expressed at low levels in the healthy human brain and is markedly upregulated in response to brain injury and inflammation. This increase in TSPO expression is correlated to the extent of microglial activation, making the measurement of TSPO density a useful indicator of active brain disease. Several classes of TSPO radioligands have therefore been developed and evaluated for use in PET, to track the progression and severity of neuroinflammatory disease. TSPO is also overexpressed in cancer and peripheral inflammation, making TSPO PET ligands possible candidates for the imaging of a multitude of pathologies. However, we currently possess a limited understanding about the molecular structure of TSPO and about the interaction of ligands with the protein. Furthermore, the incomplete characterization of multiple TSPO binding sites and the role of TSPO polymerization suggest that current interpretation of PET data may require further refinement. PMID:21498529

Scarf, Alana M; Kassiou, Michael

2011-05-01

65

Trigenomic chromosomes by recombination of Thinopyrum intermedium and Th. ponticum translocations in wheat  

Microsoft Academic Search

Rusts and barley yellow dwarf virus (BYDV) are among the main diseases affecting wheat production world wide for which wild\\u000a relatives have been the source of a number of translocations carrying resistance genes. Nevertheless, along with desirable\\u000a traits, alien translocations often carry deleterious genes. We have generated recombinants in a bread wheat background between\\u000a two alien translocations: TC5, ex-Thinopyrum (Th)

L. Ayala-Navarrete; H. S. Bariana; R. P. Singh; J. M. Gibson; A. A. Mechanicos; P. J. Larkin

2007-01-01

66

On the low-frequency EMI response of coincident loops over a conductive and permeable soil and corresponding background reduction schemes  

Microsoft Academic Search

The performance of metal detectors (low-frequency electromagnetic induction (EMI) devices) employed for landmine and ordnance detection is well known to be adversely affected by the soil response, a fact which is, however, not very often considered in the scientific literature. We have, therefore, started from the analytical model of a frequency domain coincident loop system over a homogeneous half-space to

Claudio Bruschini

2004-01-01

67

Translocation in Colored Light 1  

PubMed Central

The translocation of 14C-photosynthate in detached blades of sugarcane was studied under illumination from red, green, blue, and cool-white fluorescent lamps; under far-red illumination from the sun, and from incandescent lamps; and in total darkness. The percentage of basipetal translocation and the accumulation against the concentration gradient were stimulated by light from the red or blue lamps more than by green or cool-white fluorescent illumination. Basipetal translocation took place equally well in red light lacking blue irradiation and in blue light. Since the action spectrum for light-induced change in viscosity is a typical blue-type spectrum, the effect of light upon translocation is not due merely to changes in the physicochemical properties of protoplasm. Basipetal translocation took place in red light lacking blue irradiation better than in cool-white fluorescent light, which may suggest a red stimulation of translocation. Illumination in the far-red region of the spectrum did not support basipetal translocation but acted like total darkness. Because of the wide emission characteristics of the fluorescent lamps employed, it is impossible to decide whether a chlorophyll-like system or some other pigment is involved in the light stimulation of phototranslocation. Whatever the activating wavelength and whatever the pigment system involved, these results show that the phototranslocation of sucrose in the phloem is influenced by the quality of illumination.

Hartt, Constance E.

1966-01-01

68

Abdominal radiation causes bacterial translocation  

SciTech Connect

The purpose of this study was to determine if a single dose of radiation to the rat abdomen leads to bacterial translocation into the mesenteric lymph nodes (MLN). A second issue addressed was whether translocation correlates with anatomic damage to the mucosa. The radiated group (1100 cGy) which received anesthesia also was compared with a control group and a third group which received anesthesia alone but no abdominal radiation. Abdominal radiation lead to 100% positive cultures of MLN between 12 hr and 4 days postradiation. Bacterial translocation was almost nonexistent in the control and anesthesia group. Signs of inflammation and ulceration of the intestinal mucosa were not seen until Day 3 postradiation. Mucosal damage was maximal by Day 4. Bacterial translocation onto the MLN after a single dose of abdominal radiation was not apparently dependent on anatomical, histologic damage of the mucosa.

Guzman-Stein, G.; Bonsack, M.; Liberty, J.; Delaney, J.P.

1989-02-01

69

Diplopia after limited macular translocation surgery  

Microsoft Academic Search

Purpose: Full macular translocation surgery relocates the fovea away from choroidal neovascularization, inducing significant postoperative torsional diplopia. In “limited macular translocation,” a saline-induced retinal detachment is followed by scleral imbrication with mattress sutures and spontaneous retinal reattachment. In this study, diplopia was characterized in patients treated with limited macular translocation. Methods: Two surgeons performed retinal translocation surgery on 250 patients

Angela N. Buffenn; Eugene de Juan; Gildo Fujii; David G. Hunter

2001-01-01

70

Translocation junctions in TCF3-PBX1 acute lymphoblastic leukemia/lymphoma cluster near transposable elements  

PubMed Central

Background Hematolymphoid neoplasms frequently harbor recurrent genetic abnormalities. Some of the most well recognized lesions are chromosomal translocations, and many of these are known to play pivotal roles in pathogenesis. In lymphoid malignancies, some translocations result from erroneous V(D)J-type events. However, other translocation junctions appear randomly positioned and their underlying mechanisms are not understood. Results We tested the hypothesis that genomic repeats, including both simple tandem and interspersed repeats, are involved in chromosomal translocations arising in hematopoietic malignancies. Using a database of translocation junctions and RepeatMasker annotations of the reference genome assembly, we measured the proximity of translocation sites to their nearest repeat. We examined 1,174 translocation breakpoints from 10 classifications of hematolymphoid neoplasms. We measured significance using Student’s t-test, and we determined a false discovery rate using a random permutation statistics technique. Conclusions Most translocations showed no propensity to involve genomic repeats. However, translocation junctions at the transcription factor 3 (TCF3)/E2A immunoglobulin enhancer binding factors E12/E47 (E2A) locus clustered within, or in proximity to, transposable element sequences. Nearly half of reported TCF3 translocations involve a MER20 DNA transposon. Based on this observation, we propose this sequence is important for the oncogenesis of TCF3-PBX1 acute lymphoblastic leukemia.

2013-01-01

71

Lower Frequency of Insulin Pump Treatment in Children and Adolescents of Turkish Background with Type 1 Diabetes: Analysis of 21,497 Patients in Germany  

PubMed Central

Abstract Aim This study investigated insulin pump therapy in pediatric patients with type 1 diabetes and Turkish origin compared with those without migration background in Germany. Subjects and Methods Using a nationwide documentation program, we estimated the prevalence of insulin pump therapy in patients<20 years of age with Turkish origin and those without migration background. Logistic regression was used to adjust for age, sex, diabetes duration, body mass index SD score (BMI-SDS), glycated hemoglobin, number of outpatient visits, number of daily blood glucose self-measurements, and area-based socioeconomic conditions. Results In 1,695 pediatric type 1 diabetes patients with Turkish background and 19,802 patients without migration background (respectively: 51.2% and 53.0% boys; mean age, 12.4±4.1 and 12.6±4.2 years; mean diabetes duration, 4.7±3.9 and 5.3±4.0 years), fully adjusted prevalences of insulin pump therapy were 18.5% and 30.9%, respectively (odds ratio 0.51, 95% confidence interval 0.43–0.60, P<0.001). Age, sex, BMI-SDS, outpatient visits, and blood glucose self-control were significantly associated with the prevalence of insulin pump therapy but did not alter the difference substantially. Conclusions The prevalence of insulin pump therapy is roughly half among pediatric diabetes patients with Turkish background compared with those without migration background. Several covariates could not explain this difference. Individual characteristics or access barriers within the healthcare system may play a role. Further research is needed.

Razum, Oliver; Rosenbauer, Joachim; Bachle, Christina; Hungele, Andreas; Monkemoller, Kirsten; Muller-Godeffroy, Esther; Heidtmann, Bettina; Kapellen, Thomas; Scheuing, Nicole; Holl, Reinhard W.

2012-01-01

72

Nonequilibrium Dynamics of Polymer Translocation  

NASA Astrophysics Data System (ADS)

When a flexible chain is pulled or sucked, it can initially respond only locally, and sequential nonequilibrium processes with large conformational distortion follow in line with the propagation of tensile force along the chain backbone. This is a generic dynamical response property of polymers, the understanding of which provides us with a viewpoint to capture an essential aspect of the driven translocation process. In the meeting, I will summarize a basic framework to analyze the nonequilibrium dynamics of driven translocation process alongside of recent progresses. [4pt] References:[0pt] T. Sakaue, Phys. Rev. E, 76, 021803 (2007) ``Nonequilibrium dynamics of polymer translocation and straightening''[0pt] T. Sakaue, Phys. Rev. E, 81, 041808 (2010) ``Sucking genes into pores: Insight into driven translocation''[0pt] T. Saito and T. Sakaue, Eur. Phys. J. E, 34, 145 (2011) ``Dynamical diagram and scaling in polymer driven translocation''[0pt] T. Saito and T. Sakaue, Phys. Rev. E, 85, 061803 (2012) ``Process time distribution of driven polymer transport''

Sakaue, Takahiro

2013-03-01

73

Root Absorption and Xylem Translocation  

NSDL National Science Digital Library

Overview: Herbicides must be absorbed into plants inorder to be effective. Plant roots and below ground shoots have fewbarriers to herbicide absorption; however, interactions with soilparticles and soil organic matter have significant impacts on theamount of herbicide available for plant absorption. Plant roots andbelow ground shoots (hypocotyls or coleoptiles) are lipophilic bynature and do not have thick, waxy cuticles like leaves. Lipophilic andhydrophilic herbicides reach the root surface by bulk transport in soilwater; however, there are a few examples of herbicides that reach theroot as a vapor or gas. Soil-applied herbicides can translocate to theshoot or remain in the root system. Soil-applied herbicides translocateto the shoot in the xylem and tend to accumulate in mature leaves thattranspire the most water. The lipophilic/hydrophilic nature of theherbicide will determine if the herbicide translocates to the shoot.Absorption and translocation of phloem-mobile herbicides will bediscussed in another lesson.

74

Recent Translocation Results Using Navigation Satellites.  

National Technical Information Service (NTIS)

Translocation, as applied by users of the Navy Navigation Satellite System (NNSS), is a procedure used to position one receiver with respect to another using data acquired simultaneously by both receivers. The translocation process minimizes the effect of...

F. M. Gloeckler

1972-01-01

75

Adaptive background model  

NASA Astrophysics Data System (ADS)

An adaptive background model aiming at outdoor vehicle detection is presented in this paper. This model is an improved model of PICA (pixel intensity classification algorithm), it classifies pixels into K-distributions by color similarity, and then a hypothesis that the background pixel color appears in image sequence with a high frequency is used to evaluate all the distributions to determine which presents the current background color. As experiments show, the model presented in this paper is a robust, adaptive and flexible model, which can deal with situations like camera motions, lighting changes and so on.

Lu, Xiaochun; Xiao, Yijun; Chai, Zhi; Wang, Bangping

2007-11-01

76

Cosmic microwave background radiation  

Microsoft Academic Search

The cosmic microwave background radiation (CMBR) is widely interpreted as the thermal afterglow of a hot big bang. Measurements of the CMBR intensity as a function of frequency constrain the history of cosmic energetics. Measurements of the anisotropy in the CMBR temperature provide a snapshot of the distribution of fluctuations in the gravitational potential at the earliest stages of cosmic

Lyman Page; David Wilkinson

1999-01-01

77

Effect of fundamental-frequency and sentence-onset differences on speech-identification performance of young and older adults in a competing-talker background.  

PubMed

This study investigated the benefits of differences between sentences in fundamental frequency (F0) and temporal onset for sentence pairs among listener groups differing in age and hearing sensitivity. Two experiments were completed with the primary difference between experiments being the way in which the stimuli were presented. Experiment 1 used blocked stimulus presentation, which ultimately provided redundant acoustic cues to mark the target sentence in each pair, whereas Experiment 2 sampled a slightly more restricted stimulus space, but in a completely randomized presentation order. For both experiments, listeners were required to detect a cue word ("Baron") for the target sentence in each pair and to then identify the target words (color, number) that appeared later in the target sentence. Results of Experiment 1 showed that F0 or onset separation cues were beneficial to both cue-word detection and color-number identification performance. There were no significant differences across groups in the ability to detect the cue word, but groups differed in their ability to identify the correct color-number words. Elderly adults with impaired hearing had the greatest difficulty with the identification task despite the application of spectral shaping to restore the audibility of the speech stimuli. For the most part, the primary results of Experiment 1 were replicated in Experiment 2, although, in the latter experiment, all older adults, whether they had normal or impaired hearing, performed worse than young adults with normal hearing. From Experiment 2, the benefits received for a difference in F0 between talkers of 6 semitones were equivalent to those received for an onset asynchrony of 300 ms between sentences and, for such conditions, the combination of both sound-segregation cues resulted in an additive benefit. PMID:22978898

Lee, Jae Hee; Humes, Larry E

2012-09-01

78

RASSF1A methylation is predictive of poor prognosis in female breast cancer in a background of overall low methylation frequency.  

PubMed

Breast cancer (BC) is the most common cancer worldwide. The Kingdom of Saudi Arabia is no exception, with ever increasing incidence rates. An interesting feature of this disease is the relatively young age of the affected women. The average age in the present cohort of 100 sporadic cases of invasive ductal carcinomas was 45 years, with a median of 46 years (range between 19-81 years). In an effort to understand the molecular signature of BC in the Saudi population, we undertook this study to profile the methylation events in a series of key genes including Ras association (RalGDS/AF-6) domain family member 1 isoform a (RASSF1A), hypermethylated in cancer 1 (HIC1), cyclin-dependent kinase inhibitor 2A (CDKN2A), retinoic acid receptor beta (RARB2), estrogen receptor 1 (ESR1), progesterone receptor (PGR), paired-like homeodomain 2 (PITX2), secreted frizzled-related protein 1 (SFRP1), myogenic differentiation 1 (MYOD1), and slit homolog 2 (SLIT2), using MethyLight analysis in archival tumour samples. Interestingly, the overall methylation levels were low in this cohort, with only 84% of the cases displaying methylation in one or more of the analysed genes. The frequency of RASSF1A methylation was the highest (65%), while there was almost complete absence of methylation of the ESR1 and the CDH1 genes (1% and 3%, respectively). Several statistically significant correlations were identified between specific methylation events and clinical parameters which gained more significance when analysis was limited to the estrogen receptor positive samples. Although there was no significant correlations between any methylation event and disease-specific survival, methylation of MYOD1 or RASSF1A was associated with lower disease-free survival and increased chance of disease recurrence. Furthermore, multivariate (Cox) regression analysis identified RASSF1A as an independent predictor of poor prognosis in terms of disease-free survival in this cohort. Our findings provide further evidence on the usefulness of RASSF1A methylation status as an informative prognostic biomarker in BC in a Saudi population. PMID:21868547

Buhmeida, Abdelbaset; Merdad, Adnan; Al-Maghrabi, Judah; El-Maghrabi, Joudah; Al-Thobaiti, Fatima; Ata, Manar; Bugis, Ayman; Syrjänen, Kari; Abuzenadah, Adel; Chaudhary, Adeel; Gari, Mamdooh; Al-Qahtani, Mohammed; Dallol, Ashraf

2011-09-01

79

PARP1 is required for chromosomal translocations  

PubMed Central

Chromosomal translocations are common contributors to malignancy, yet little is known about the precise molecular mechanisms by which they are generated. Sequencing translocation junctions in acute leukemias revealed that the translocations were likely mediated by a DNA double-strand break repair pathway termed nonhomologous end-joining (NHEJ). There are major 2 types of NHEJ: (1) the classical pathway initiated by the Ku complex, and (2) the alternative pathway initiated by poly ADP-ribose polymerase 1 (PARP1). Recent reports suggest that classical NHEJ repair components repress translocations, whereas alternative NHEJ components were required for translocations. The rate-limiting step for initiation of alternative NHEJ is the displacement of the Ku complex by PARP1. Therefore, we asked whether PARP1 inhibition could prevent chromosomal translocations in 3 translocation reporter systems. We found that 2 PARP1 inhibitors or repression of PARP1 protein expression strongly repressed chromosomal translocations, implying that PARP1 is essential for this process. Finally, PARP1 inhibition also reduced both ionizing radiation–generated and VP16-generated translocations in 2 cell lines. These data define PARP1 as a critical mediator of chromosomal translocations and raise the possibility that oncogenic translocations occurring after high-dose chemotherapy or radiation could be prevented by treatment with a clinically available PARP1 inhibitor.

Wray, Justin; Williamson, Elizabeth A.; Singh, Sudha B.; Wu, Yuehan; Cogle, Christopher R.; Weinstock, David M.; Zhang, Yu; Lee, Suk-Hee; Zhou, Daohong; Shao, Lijian; Hauer-Jensen, Martin; Pathak, Rupak; Klimek, Virginia; Nickoloff, Jac A.

2013-01-01

80

Diagnostic X-ray examinations and increased chromosome translocations: evidence from three studies  

Microsoft Academic Search

Controversy regarding potential health risks from increased use of medical diagnostic radiologic examinations has come to\\u000a public attention. We evaluated whether chromosome damage, specifically translocations, which are a potentially intermediate\\u000a biomarker for cancer risk, was increased after exposure to diagnostic X-rays, with particular interest in the ionizing radiation\\u000a dose–response below the level of approximately 50 mGy. Chromosome translocation frequency data from

Parveen Bhatti; Lee C. Yong; Michele M. Doody; Dale L. Preston; Diane M. Kampa; Marilyn J. Ramsey; Elizabeth M. Ward; Alan A. Edwards; Elaine Ron; James D. Tucker; Alice J. Sigurdson

2010-01-01

81

Facilitated Translocation of Polypeptides Through A Single Nanopore  

PubMed Central

The transport of polypeptides through nanopores is a key process in biology and medical biotechnology. Despite its critical importance, the underlying kinetics of polypeptide translocation through protein nanopores is not yet comprehensively understood. Here, we present a simple two-barrier, one-well kinetic model for the translocation of short positively charged polypeptides through a single transmembrane protein nanopore that is equiped with negatively charged rings, simply called traps. We demonstrate that the presence of these traps within the interior of the nanopore dramatically alters the free energy landscape for the partitioning of the polypeptide into the nanopore interior, as revealed by significant modifications in the activation free energies required for the transitions of the polypeptide from one state to other. Our kinetic model permits the calculation of the relative and absolute exit frequencies of the short cationic polypeptides through either opening of the nanopore. Moreover, this approach enabled quantitative assessment of the kinetics of translocation of the polypeptides through a protein nanopore, which is strongly dependent on several factors, including the nature of the translocating polypeptide, the position of the traps, the strength of the polypeptide-attractive trap interactions and the applied transmembrane voltage.

Bikwemu, Robert; Wolfe, Aaron J.; Xing, Xiangjun; Movileanu, Liviu

2011-01-01

82

Toponomics method for the automated quantification of membrane protein translocation  

PubMed Central

Background Intra-cellular and inter-cellular protein translocation can be observed by microscopic imaging of tissue sections prepared immunohistochemically. A manual densitometric analysis is time-consuming, subjective and error-prone. An automated quantification is faster, more reproducible, and should yield results comparable to manual evaluation. The automated method presented here was developed on rat liver tissue sections to study the translocation of bile salt transport proteins in hepatocytes. For validation, the cholestatic liver state was compared to the normal biological state. Results An automated quantification method was developed to analyze the translocation of membrane proteins and evaluated in comparison to an established manual method. Firstly, regions of interest (membrane fragments) are identified in confocal microscopy images. Further, densitometric intensity profiles are extracted orthogonally to membrane fragments, following the direction from the plasma membrane to cytoplasm. Finally, several different quantitative descriptors were derived from the densitometric profiles and were compared regarding their statistical significance with respect to the transport protein distribution. Stable performance, robustness and reproducibility were tested using several independent experimental datasets. A fully automated workflow for the information extraction and statistical evaluation has been developed and produces robust results. Conclusions New descriptors for the intensity distribution profiles were found to be more discriminative, i.e. more significant, than those used in previous research publications for the translocation quantification. The slow manual calculation can be substituted by the fast and unbiased automated method.

2011-01-01

83

DNA Ligase III Promotes Alternative Nonhomologous End-Joining during Chromosomal Translocation Formation  

PubMed Central

Nonhomologous end-joining (NHEJ) is the primary DNA repair pathway thought to underlie chromosomal translocations and other genomic rearrangements in somatic cells. The canonical NHEJ pathway, including DNA ligase IV (Lig4), suppresses genomic instability and chromosomal translocations, leading to the notion that a poorly defined, alternative NHEJ (alt-NHEJ) pathway generates these rearrangements. Here, we investigate the DNA ligase requirement of chromosomal translocation formation in mouse cells. Mammals have two other DNA ligases, Lig1 and Lig3, in addition to Lig4. As deletion of Lig3 results in cellular lethality due to its requirement in mitochondria, we used recently developed cell lines deficient in nuclear Lig3 but rescued for mitochondrial DNA ligase activity. Further, zinc finger endonucleases were used to generate DNA breaks at endogenous loci to induce translocations. Unlike with Lig4 deficiency, which causes an increase in translocation frequency, translocations are reduced in frequency in the absence of Lig3. Residual translocations in Lig3-deficient cells do not show a bias toward use of pre-existing microhomology at the breakpoint junctions, unlike either wild-type or Lig4-deficient cells, consistent with the notion that alt-NHEJ is impaired with Lig3 loss. By contrast, Lig1 depletion in otherwise wild-type cells does not reduce translocations or affect microhomology use. However, translocations are further reduced in Lig3-deficient cells upon Lig1 knockdown, suggesting the existence of two alt-NHEJ pathways, one that is biased toward microhomology use and requires Lig3 and a back-up pathway which does not depend on microhomology and utilizes Lig1.

Wong, Sunnie Yan-Wai; Katyal, Sachin; Gao, Yankun; McKinnon, Peter J.; Lou, Jacqueline; Zhang, Lei; Li, James; Rebar, Edward J.; Gregory, Philip D.; Holmes, Michael C.; Jasin, Maria

2011-01-01

84

Long-term outcomes following full macular translocation surgery in neovascular age-related macular degeneration  

Microsoft Academic Search

Background\\/aimsLong-term data of macular translocation for choroidal neovascularisation (CNV) secondary to age-related macular degeneration is lacking. Therefore, we describe the 3-year acuity outcomes.MethodsThis is a retrospective, interventional case series consisting of 40 consecutive patients who underwent translocation between 2003 and 2008. Best-corrected visual acuity (BCVA) at the most recent follow-up visit was compared to that of the 1 year and

Fred K Chen; Praveen J Patel; Gurmit S Uppal; Adnan Tufail; Peter J Coffey; Lyndon Da Cruz

2010-01-01

85

Tasmanian low frequency Galactic background surveys  

NASA Technical Reports Server (NTRS)

The results of LF (2-20-MHz) radio-astronomy observations obtained in Tasmania during solar-minimum winters since 1956 are briefly summarized. The low ionospheric f0F2 values (near 1 MHz) occurring in Tasmania in these periods are noted; the 2000-ft-diameter Llanherne array used for Galactic mapping at 2-20 MHz is described; the techniques employed are discussed; and sample maps are shown.

Cane, H. V.

1987-01-01

86

The cellular etiology of chromosome translocations  

PubMed Central

Chromosome translocations are the most severe form of genome defect. Translocations represent the end product of a series of cellular mistakes and they form after cells suffer multiple DNA double strand breaks (DSBs), which evade the surveillance mechanisms that usually eliminate them. Rather than being accurately repaired, translocating DSBs are misjoined to form aberrant fusion chromosomes. Although translocations have been extensively characterized using cytological methods and their pathological relevance in cancer and numerous other diseases is well established, how translocations form in the context of the intact cell nucleus is poorly understood. A combination of imaging approaches and biochemical methods to probe genome architecture and chromatin structure suggest that the spatial organization of the genome and features of chromatin, including sequence properties, higher order chromatin structure and histone modifications, are key determinants of translocation formation.

Roukos, Vassilis; Burman, Bharat; Misteli, Tom

2013-01-01

87

Outcome of preimplantation genetic diagnosis of translocations  

Microsoft Academic Search

Objective: To review 35 cases of preimplantation genetic diagnosis (PGD) of translocations with several methods, including telomeric probes.Design: Retrospective study.Setting: Clinical IVF laboratory.Patient(s): Thirty-five couples with one partner carrying a chromosomal translocation.Intervention(s): PGD of translocation after polar-body or embryo biopsy.Main Outcome Measure(s): Pregnancy outcome.Result(s): Several trends were observed. First, PGD can achieve a statistically significant reduction in spontaneous abortion, from

Santiago Munné; Mireia Sandalinas; Tomas Escudero; Jingly Fung; Luca Gianaroli; Jacques Cohen

2000-01-01

88

DNA translocation through grapheme nanopores  

NASA Astrophysics Data System (ADS)

We report on DNA translocations through nanopores created in graphene membranes. Devices consist of nanometer-thick graphene membranes with electron-beam sculpted nanopores. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore.

Merchant, Christopher A.; Healy, Ken; Wanunu, Meni; Ray, Vishva; Peterman, Neil; Bartel, John; Fischbein, Michael D.; Venta, Kim; Luo, Zhengtang; Johnson, A. T. Charlie; Drndic, Marija

2011-03-01

89

Population demographics and genetic diversity in remnant and translocated populations of sea otters  

USGS Publications Warehouse

The effects of small population size on genetic diversity and subsequent population recovery are theoretically predicted, but few empirical data are available to describe those relations. We use data from four remnant and three translocated sea otter (Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variation. Metochondrial (mt)DNA haplotype diversity was correlated with the number of years at minimum population size (r = -0.741, p = 0.038) and minimum population size (r = 0.709, p = 0.054). We found no relation between population growth and haplotype diversity, altough growth was significantly greater in translocated than in remnant populations. Haplotype diversity in populations established from two sources was higher than in a population established from a single source and was higher than in the respective source populations. Haplotype frequencies in translocated populations of founding sizes of 4 and 28 differed from expected, indicating genetic drift and differential reproduction between source populations, whereas haplotype frequencies in a translocated population with a founding size of 150 did not. Relations between population demographics and genetic characteristics suggest that genetic sampling of source and translocated populations can provide valuable inferences about translocations.

Bodkin, J. L.; Ballachey, B. E.; Cronin, M. A.; Scribner, K. T.

1999-01-01

90

Effects of gravity wave dissipation on the thermosphere and ionosphere from deep convection: Excitation of secondary gravity waves, and large-scale changes to the background neutral wind, temperature, plasma frequency, and TEC  

NASA Astrophysics Data System (ADS)

In this talk, we discuss how the propagation and dissipation of gravity waves in the thermosphere affect both the thermosphere and ionosphere. We then discuss the propagation and dissipation of gravity waves excited by deep convection. We show that secondary gravity waves are excited by both the body forcing and the heating/cooling which accompany the dissipation of these gravity waves in the thermosphere. We show new global simulation results which model the gravity wave effects in the thermosphere and ionosphere from deep convection over the entire Earth for a 13 day period during the recent extreme solar minimum. We find that large-scale changes in the background neutral wind, temperature, plasma frequency, and TEC accompany the dissipation of these convectively-generated gravity waves.

Vadas, S. L.; Liu, H.

2012-12-01

91

Insulin Phosphorylates Tyrosine Residue 464 of Tub and Translocates Tubby into the Nucleus in HIRcB Cells  

PubMed Central

Background The tubby protein has a motif that might be relevant for its action in the insulin signaling pathway. Previous studies have indicated that tubby undergoes phosphorylation on tyrosine residues in response to several stimuli and is known to localize in the nucleus as well as in the plasma membrane. However, the relationship between phosphorylation and nuclear translocation is not well understood. Here, we report that insulin directly phosphorylates tubby, which translocates into the nucleus. Methods The effects of insulin on Tubby were performed with Western blot. The immunoprecipitation and confocal microscopy were performed to prove phosphorylation and nuclear translocation. Results Mutation study reveals that tyrosine residue 464 of tubby gene (Tub) is a phosphorylation site activated by insulin. In addition, major portions of tubby protein in the plasma membrane are translocated into the nucleus after insulin treatment. Tyrosine kinase inhibitor pretreatment blocked insulin-induced tubby translocation, suggesting that phosphorylation is important for nuclear translocation. Moreover, mutant tyrosine residue 464 did not translocate into the nucleus in respond to insulin. These findings demonstrate that insulin phosphorylates tyrosine residue 464 of Tub, and this event is important for insulin-induced tubby nuclear translocation. Conclusion Insulin phosphorylates tyrosine residue 464 of Tub and translocates tubby into the nuclei of HIRcB cells.

Kim, Jin Wook; Kim, Hyeon Soo; Kim, Sang Dae

2014-01-01

92

Role of the translocation partner in protection against AID-dependent chromosomal translocations.  

PubMed

Chromosome translocations between Ig (Ig) and non-Ig genes are frequently associated with B-cell lymphomas in humans and mice. The best characterized of these is c-myc/IgH translocation, which is associated with Burkitt's lymphoma. These translocations are caused by activation-induced cytidine deaminase (AID), which produces double-strand DNA breaks in both genes. c-myc/IgH translocations are rare events, in part because ATM, p53, and p19 actively suppress them. To further define the mechanism of protection against the accumulation of cells that bear c-myc/IgH translocation, we assayed B cells from mice that carry mutations in cell-cycle and apoptosis regulator proteins that act downstream of p53. We find that PUMA, Bim, and PKCdelta are required for protection against c-myc/IgH translocation, whereas Bcl-XL and BAFF enhance c-myc/IgH translocation. Whether these effects are general or specific to c-myc/IgH translocation and whether AID produces dsDNA breaks in genes other than c-myc and Ig is not known. To examine these questions, we developed an assay for translocation between IgH and Igbeta, both of which are somatically mutated by AID. Igbeta/IgH, like c-myc/IgH translocations, are AID-dependent, and AID is responsible for lesions on IgH and the non-IgH translocation partners. However, ATM, p53, and p19 do not protect against Igbeta/IgH translocations. Instead, B cells are protected against Igbeta/IgH translocations by a BAFF- and PKCdelta-dependent pathway. We conclude that AID-induced double-strand breaks in non-Ig genes other than c-myc lead to their translocation, and that at least two nonoverlapping pathways protect against translocations in primary B cells. PMID:19966290

Jankovic, Mila; Robbiani, Davide F; Dorsett, Yair; Eisenreich, Thomas; Xu, Yang; Tarakhovsky, Alexander; Nussenzweig, Andre; Nussenzweig, Michel C

2010-01-01

93

Gold nanoparticle translocation dynamics and electrical detection of single particle diffusion using solid-state nanopores.  

PubMed

This paper describes the use of gold nanoparticles to study particle translocation dynamics through silicon nitride solid-state nanopores. Gold nanoparticles were dispersed in 20 mM KCl solution containing nonionic surfactant Triton X-100 and their translocation was studied at different applied voltages. The use of low electrolyte concentration resulted in current enhancement upon particle translocation. The counterion cloud around the nanoparticles is proposed to be the reason for current enhancement phenomena because associated counterion cloud is believed to increase the ion density inside the pore during particle translocation. Further, single particle diffusion events were also recorded at 0 mV voltage bias and 0 pA background ionic current with high signal-to-noise ratio as the particles moved down their concentration gradient. The ability of nanopore sensors to detect single particle diffusion can be extended to field-free analysis of biomolecules in their native state and at or near physiological salt concentrations. PMID:23885645

Goyal, Gaurav; Freedman, Kevin J; Kim, Min Jun

2013-09-01

94

Bacterial translocation from the gastrointestinal tract  

Microsoft Academic Search

Bacterial translocation is defined as the passage of viable indigenous bacteria from the gastrointestinal tract to extraintestinal sites, such as the mesenteric-lymph-node complex, liver, spleen and bloodstream. Three major mechanisms promote bacterial translocation: intestinal bacterial overgrowth, deficiencies in host immune defenses and increased permeability or damage to the intestinal mucosal barrier.

Rodney D. Berg

1995-01-01

95

Remembering the city: translocality and the senses  

Microsoft Academic Search

This article explores how the postcolonial cities of Kolkata and London are remembered across space and time through the translocal memories of a religious minority, followers of the Hindu reform sect, known as the Brahmo Samaj. London Brahmos represent a miniscule translocal community, historically located in the urban culture of Kolkata and yet with a long tradition of travel and

Shompa Lahiri

2011-01-01

96

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Rodent heritable translocation assays. 798.5460 Section 798...Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This...which manifests as balanced reciprocal translocations in progeny descended from...

2009-07-01

97

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Rodent heritable translocation assays. 798.5460 Section 798...Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This...which manifests as balanced reciprocal translocations in progeny descended from...

2010-07-01

98

RNA polymerase stalls in a post-translocated register and can hyper-translocate  

PubMed Central

Exonuclease (Exo) III was used to probe translocation states of RNA polymerase (RNAP) ternary elongation complexes (TECs). Escherichia coli RNAP stalls primarily in a post-translocation register that makes relatively slow excursions to a hyper-translocated state or to a pre-translocated state. Tagetitoxin (TGT) strongly inhibits hyper-translocation and inhibits backtracking, so, as indicated by Exo III mapping, TGT appears to stabilize both the pre- and probably a partially post-translocation state of RNAP. Because the pre-translocated to post-translocated transition is slow at many template positions, these studies appear inconsistent with a model in which RNAP makes frequent and rapid (i.e., millisecond phase) oscillations between pre- and post-translocation states. Nine nucleotides (9-nt) and 10-nt TECs, and TECs with longer nascent RNAs, have distinct translocation properties consistent with a 9–10 nt RNA/DNA hybrid. RNAP mutant proteins in the bridge helix and trigger loop are identified that inhibit or stimulate forward and backward translocation.

Nedialkov, Yuri A.; Nudler, Evgeny; Burton, Zachary F.

2012-01-01

99

Electrically facilitated translocation of protein through solid nanopore  

PubMed Central

Nanopores have been proven as versatile single-molecule sensors for individual unlabeled biopolymer detection and characterization. In the present work, a relative large nanopore with a diameter of about 60 nm has been used to detect protein translocation driven by a series of applied voltages. Compared with previous studied small nanopores, a distinct profile of protein translocation through a larger nanopore has been characterized. First, a higher threshold voltage is required to drive proteins into the large nanopore. With the increase of voltages, the capture frequency of protein into the nanopore has been markedly enhanced. And the distribution of current blockage events is characterized as a function of biased voltages. Due to the large dimension of the nanopore, the adsorption and desorption phenomenon of proteins observed with a prolonged dwell time has been weakened in our work. Nevertheless, the protein can still be stretched into an unfolded state by increased electric forces at high voltages. In consideration of the high throughput of the large nanopore, a couple of proteins passing through the nanopore simultaneously occur at high voltage. As a new feature, the feasibility and specificity of a nanopore with distinct geometry have been demonstrated for sensing protein translocation, which broadly expand the application of nanopore devices.

2014-01-01

100

Electrically facilitated translocation of protein through solid nanopore.  

PubMed

Nanopores have been proven as versatile single-molecule sensors for individual unlabeled biopolymer detection and characterization. In the present work, a relative large nanopore with a diameter of about 60 nm has been used to detect protein translocation driven by a series of applied voltages. Compared with previous studied small nanopores, a distinct profile of protein translocation through a larger nanopore has been characterized. First, a higher threshold voltage is required to drive proteins into the large nanopore. With the increase of voltages, the capture frequency of protein into the nanopore has been markedly enhanced. And the distribution of current blockage events is characterized as a function of biased voltages. Due to the large dimension of the nanopore, the adsorption and desorption phenomenon of proteins observed with a prolonged dwell time has been weakened in our work. Nevertheless, the protein can still be stretched into an unfolded state by increased electric forces at high voltages. In consideration of the high throughput of the large nanopore, a couple of proteins passing through the nanopore simultaneously occur at high voltage. As a new feature, the feasibility and specificity of a nanopore with distinct geometry have been demonstrated for sensing protein translocation, which broadly expand the application of nanopore devices. PMID:24661490

Wu, Lingzhi; Liu, Hang; Zhao, Wenyuan; Wang, Lei; Hou, Chuanrong; Liu, Quanjun; Lu, Zuhong

2014-01-01

101

Electrically facilitated translocation of protein through solid nanopore  

NASA Astrophysics Data System (ADS)

Nanopores have been proven as versatile single-molecule sensors for individual unlabeled biopolymer detection and characterization. In the present work, a relative large nanopore with a diameter of about 60 nm has been used to detect protein translocation driven by a series of applied voltages. Compared with previous studied small nanopores, a distinct profile of protein translocation through a larger nanopore has been characterized. First, a higher threshold voltage is required to drive proteins into the large nanopore. With the increase of voltages, the capture frequency of protein into the nanopore has been markedly enhanced. And the distribution of current blockage events is characterized as a function of biased voltages. Due to the large dimension of the nanopore, the adsorption and desorption phenomenon of proteins observed with a prolonged dwell time has been weakened in our work. Nevertheless, the protein can still be stretched into an unfolded state by increased electric forces at high voltages. In consideration of the high throughput of the large nanopore, a couple of proteins passing through the nanopore simultaneously occur at high voltage. As a new feature, the feasibility and specificity of a nanopore with distinct geometry have been demonstrated for sensing protein translocation, which broadly expand the application of nanopore devices.

Wu, Lingzhi; Liu, Hang; Zhao, Wenyuan; Wang, Lei; Hou, Chuanrong; Liu, Quanjun; Lu, Zuhong

2014-03-01

102

Construction of comparative genetic maps of two 4Bs.4Bl-5Rl translocations in bread wheat (Triticum aestivum L.).  

PubMed

The physical length of the rye segment of a 4BS.4BL-5RL translocation derived from the Cornell Wheat Selection 82a1-2-4-7 in a Triticum aestivum 'Chinese Spring' background was measured using genomic in situ hybridization (GISH) and found to be 16% of the long arm. The size of this translocation was similar to previously published GISH measurements of another 4BS.4BL-5RL translocation in a Triticum aestivum 'Viking' wheat background. Molecular maps of both 4BS.4BL-5RL translocations for 2 different wheat backgrounds were developed using RFLP analysis. The locations of the translocation breakpoints of the 2 4BS.4BL-5RL translocations were similar even though they arose in different populations. This suggests a unique property of the region at or near the translocation breakpoint that could be associated with their similarity and spontaneous formation. These segments of rye chromosome 5 also contain a gene for copper efficiency that improves the wheat's ability to cope with low-copper soils. Genetic markers in these maps can also be used to screen for copper efficiency in bread wheat lines derived from the Cornell Wheat Selection 82a1 2-4-7. PMID:16936781

Leach, R C; Dundas, I S; Houben, A

2006-07-01

103

Direct segregation analysis of reciprocal translocations: a study of 283 sperm karyotypes from four carriers.  

PubMed Central

Using the technique of in vitro human-hamster fertilization, sperm of four men heterozygous for 4 reciprocal translocations--t(4;17),t(5;13),t(6;7), and t(9;18)--was studied. Frequencies of numerical abnormalities unrelated to the translocations range from 8.3% to 13.3%, and the incidence of imbalances ranges from 23.0% to 66.0%. Results are pooled with data from the nine other reciprocal translocations reported elsewhere, and the combined data demonstrate that male meiotic segregation is not random: whatever the type of translocation may be, the distribution of imbalances in sperm is constant, with approximately 72.0% adjacent 1, 18.5% adjacent 2, and 9.5% 3:1 segregations. The same prevalence of adjacent 1 segregations as that reported at term for translocations of paternal origin is observed. There is a strong postzygotic elimination process; for a given translocation it affects selectively the maximum-imbalance zygotes so that imbalanced segregations observed at term are always predetermined. Images Figure 4 Figure 2 Figure 3 Figure 5

Pellestor, F; Sele, B; Jalbert, H; Jalbert, P

1989-01-01

104

Double Translocation: An Interesting Family History  

PubMed Central

Double balanced translocations are particularly rare and the risk of a fetus with an unbalanced chromosomal anomaly is greater than for single translocation carriers. In this present case, we describe an interesting family history which included three generations. A couple, married for 4 years, was referred to the genetic clinic due to infertility and family chromosome anomalies. A GTG-band chromosome analysis indicated that the male partner’s karyotype was 45,XY, t(3;18)(q11;ptel)t(13;14)(q10;q10). The same double balanced translocation was found in two others family members.

Uysal, A; Uludag, A; S?lan, F; Ercelen, N; Zafer, C; Ozdemir, O

105

Polymer translocation: the effect of backflow.  

PubMed

We investigate the effect of backflow on the translocation dynamics of short, flexible polymer chains threading through a small hole in a wall. We find that hydrodynamic interactions between polymer beads play an important role in determining the translocation time distribution: as a monomer moves through the hole it sets up a flow field which transfers momentum to neighboring monomers, thus helping them to move in the same direction. Translocation times are calculated by using the velocity-Verlet algorithm to solve the equations of motion of a polymer which moves in a fluid described by the stochastic rotation algorithm, a particle-based Navier-Stokes solver. PMID:16392945

Ali, I; Yeomans, J M

2005-12-15

106

Polymer translocation induced by bad solvent  

NASA Astrophysics Data System (ADS)

We report Langevin dynamics simulation studies of a translocating homopolymer through a nano pore induced by different existing solvent conditions at the cis and trans compartments of the pore. Specifically, we study the mean first passage time as a function of the chain length N and determine the scaling exponent ˜N^?. We also look at the mean force experienced by the chain and its conformations as a function of the translocated segments. Our studies also reveal detail picture of the translocation process which may provide insights relevant for the entry of a DNA into a host cell.

Lorscher, Christopher; Bhattacharya, Aniket; Ala-Nissila, Tapio

2009-03-01

107

DNA translocation through a periodically patterned nanoprobe  

NASA Astrophysics Data System (ADS)

The Al Nano apertures surrounded by periodic patterns on the pyramidal structures were fabricated. The nanometric size aperture with ~ 100 nm diameter surrounded by equidistant elliptic groove patterns presented greater transmission than the aperture with circular groove patterns. The translocation of ?-DNA through these fabricated nanostructures was tested using electrically biased techniques. We observed the strong fluorescent optical signal from the translocated DNA through the nanoprobe with a charge coupled device camera. The optical force driven DNA translocation though a nanoprobe surrounded with elliptically patterned grooves is under investigation.

Choi, Seong Soo; Park, Myoung Jin; Park, Nam kyou; Park, Seung Min; Lee, Luke

2013-05-01

108

Evidence of Microbial Translocation Associated with Perturbations in T Cell and Antigen-Presenting Cell Homeostasis in Hookworm Infections  

PubMed Central

Background Microbial translocation (MT) is the process by which microbes or microbial products translocate from the intestine to the systemic circulation. MT is a common cause of systemic immune activation in HIV infection and is associated with reduced frequencies of CD4+ T cells; no data exist, however, on the role of MT in intestinal helminth infections. Methods We measured the plasma levels of MT markers, acute-phase proteins, and pro- and anti - inflammatory cytokines in individuals with or without hookworm infections. We also estimated the absolute counts of CD4+ and CD8+ T cells as well as the frequencies of memory T cell and dendritic cell subsets. Finally, we also measured the levels of all of these parameters in a subset of individuals following treatment of hookworm infection. Results Our data suggest that hookworm infection is characterized by increased levels of markers associated with MT but not acute-phase proteins nor pro-inflammatory cytokines. Hookworm infections were also associated with increased levels of the anti – inflammatory cytokine – IL-10, which was positively correlated with levels of lipopolysaccharide (LPS). In addition, MT was associated with decreased numbers of CD8+ T cells and diminished frequencies of particular dendritic cell subsets. Antihelmintic treatment of hookworm infection resulted in reversal of some of the hematologic and microbiologic alterations. Conclusions Our data provide compelling evidence for MT in a human intestinal helminth infection and its association with perturbations in the T cell and antigen-presenting cell compartments of the immune system. Our data also reveal that at least one dominant counter-regulatory mechanism i.e. increased IL-10 production might potentially protect against systemic immune activation in hookworm infections.

George, Palakkal Jovvian; Anuradha, Rajamanickam; Kumar, Nathella Pavan; Kumaraswami, Vasanthapuram; Nutman, Thomas B.; Babu, Subash

2012-01-01

109

Chromosomal translocations are a common phenomenon in Arabidopsis thaliana T-DNA insertion lines  

PubMed Central

SUMMARY Ordered collections of Arabidopsis thaliana lines containing mapped T-DNA insertions have become an important resource for plant scientists performing genetic studies. Previous reports have indicated that T-DNA insertion lines can have chromosomal translocations associated with the T-DNA insertion site, but the prevalence of these rearrangements has not been well documented. To determine the frequency with which translocations are present in a widely-used collection of T-DNA insertion lines, we analyzed 64 independent lines from the Salk T-DNA mutant collection. Chromosomal translocations were detected in 12 of the 64 lines surveyed (19%). Two assays were used to screen the T-DNA lines for translocations: pollen viability and genome-wide genetic mapping. Although the measurement of pollen viability is an indirect screen for the presence of a translocation, all 11 of the T-DNA lines showing an abnormal pollen phenotype were found to contain a translocation when analyzed using genetic mapping. A normal pollen phenotype does not, however, guarantee the absence of a translocation. We observed one T-DNA line with normal pollen that nevertheless had a translocation based on genetic mapping results. One additional phenomenon that we observed through our genetic mapping experiments was that the T-DNA junctions on the 5?- and 3?-sides of a targeted gene can genetically separate from each other in some cases. Two of the lines in our survey displayed this ‘T-DNA borders separate’ phenomenon. Experimental procedures for efficiently screening T-DNA lines for the presence of chromosomal abnormalities are presented and discussed.

Clark, Katie A.; Krysan, Patrick J.

2011-01-01

110

Reciprocal translocations in myelodysplastic syndromes and chronic myelomonocytic leukemias: review of 5,654 patients with an evaluable karyotype.  

PubMed

The infrequency of translocations in myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemias (CMML) makes their identification and reporting interesting for the recognition of the recurrent ones and the genes involved in these neoplasias. The aims of this study were to identify new translocations associated with MDS and CMML and to establish their frequency in a cohort of 8,016 patients from the Spanish Group of MDS database. The karyotype was evaluable in 5,654 (70%) patients. Among those, 2,014 (36%) had chromosomal abnormalities, including 213 (10%) translocations identified in 195 patients. The translocations were balanced in 183 (86%) cases and unbalanced in 30 (14%) cases. All chromosomes were found to be involved in translocations, with the single exception of the Y chromosome. The chromosomes most frequently involved were in decreasing frequency: 3, 1, 7, 2, 11, 5, 12, 6, and 17. Translocations were found in karyotypes as the unique chromosomal abnormality (33%), associated with another chromosomal abnormality (11%), as a part of a complex karyotype (17%), and as a part of a monosomal karyotype (38%). There were 155 translocations not previously described in MDS or CMML and nine of them appeared to be recurrent. PMID:23686965

Costa, Dolors; Muñoz, Concha; Carrió, Ana; Nomdedeu, Meritxell; Calvo, Xavier; Solé, Francesc; Luño, Elisa; Cervera, José; Vallespí, Teresa; Berneaga, Daniela; Gómez, Cándida; Arias, Amparo; Such, Esperanza; Sanz, Guillermo; Grau, Javier; Insunza, Andrés; Calasanz, María J; Ardañaz, María T; Hernández, Jesús M; Azaceta, Gemma; Álvarez, Sara; Sánchez, Joaquín; Martín, María L; Bargay, Joan; Gómez, Valle; Cervero, Carlos Javier; Allegue, María J; Collado, Rosa; Campo, Elias; Nomdedeu, Benet

2013-08-01

111

Gene Translocations in Musculoskeletal Neoplasms  

PubMed Central

Establishing the best diagnosis for musculoskeletal neoplasms requires a multidisciplinary approach using clinical, radiographic, and histologic analyses. Despite this rigorous approach, establishing accurate diagnoses and prognoses remains challenging. Improved diagnostic methods are expected as unique molecular signals for specific bone and soft tissue cancers are identified. We performed a systematic review of the best available evidence to explore three major applications of molecular genetics that will best benefit clinical management of musculoskeletal neoplasms: diagnostic, prognostic, and therapeutic applications. The specific questions addressed in this systematic review are: (1) What sets of histopathologic sarcoma subtypes will benefit from molecular evaluation and diagnosis? (2) What molecular methods are best applied to histopathologic sarcomas to distinguish between major subtypes? (3) How do the molecular patterns discovered on genetic diagnosis affect prognosis of certain sarcomas? (4) Which sarcoma translocations can benefit from an improved response and outcome using existing and forthcoming pharmacogenetic approaches targeting molecular events? This review summarizes recent advances in molecular genetics that are available and will soon be available to clinicians to better predict outcomes and subsequently help make future treatment decisions. Level of Evidence: Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Krishnan, Balaji; Khanna, Gaurav

2008-01-01

112

K(+) , Na(+) , and Mg(2+) on DNA translocation in silicon nitride nanopores.  

PubMed

In this work, we report on how salt concentration and cation species affect DNA translocation in voltage-biased silicon nitride nanopores. The translocation of dsDNA in linear, circular, and supercoiled forms was measured in salt solutions containing KCl, NaCl, and MgCl(2) . As the KCl concentrations were decreased from 1 to 0.1 M, the time taken by a DNA molecule to pass through a nanopore was shorter and the frequency of the translocation in a folded configuration was reduced, suggesting an increase in DNA electrophoretic mobility and DNA persistence length. When the salt concentration was kept at 1 M, but replacing K(+) with Na(+) , longer DNA translocation times (t(d) ) were observed. The addition of low concentrations of MgCl(2) with 1.6 M KCl resulted in longer t(d) and an increased frequency of supercoiled DNA molecules in a branched form. These observations were consistent with the greater counterion charge screening ability of Na(+) and Mg(2+) as compared to K(+) . In addition, we demonstrated that dsDNA molecules indeed translocated through a ?10 nm nanopore by PCR amplification and gel electrophoresis. We also compared the dependence of DNA mobility and conformation on KCl concentration and cation species measured at single molecule level by silicon nitride nanopores with existing bulk-based experimental results and theoretical predictions. PMID:23147752

Uplinger, James; Thomas, Brian; Rollings, Ryan; Fologea, Daniel; McNabb, David; Li, Jiali

2012-12-01

113

Simulation of Polymer Translocation through Protein Channels.  

National Technical Information Service (NTIS)

A modeling algorithm is presented to compute simultaneously polymer conformations and ionic current, as single polymer molecules undergo translocation through protein channels. The method is based on a combination of Langevin dynamics for coarse-grained m...

M. Muthukumar C. Y. Kong

2005-01-01

114

The influence of hydrogen peroxide and histamine on lung permeability and translocation of iridium nanoparticles in the isolated perfused rat lung  

Microsoft Academic Search

BACKGROUND: Translocation of ultrafine particles (UFP) into the blood that returns from the lungs to the heart has been forwarded as a mechanism for particle-induced cardiovascular effects. The objective of this study was to evaluate the role of the endothelial barrier in the translocation of inhaled UFP from the lung into circulation. METHODS: The isolated perfused rat lung (IPRL) was

James J Meiring; Paul JA Borm; Karim Bagate; Manuela Semmler; Jürgen Seitz; Shinji Takenaka; Wolfgang G Kreyling

2005-01-01

115

Factors predisposing to adjacent 2 and 3:1 disjunctions: study of 161 human reciprocal translocations  

Microsoft Academic Search

Reciprocal translocations produce imbalances by three types of disjunction which are, in decreasing frequency, adjacent 1, 3:1, and adjacent 2. Adjacent 1 disjunction produces duplication deficiencies of inverse topography to those of adjacent 2. The imbalanced chromosome segments in one of these types are balanced in the other. The disjunction 3:1 produces pure trisomies and monosomies. The following situations predispose

P Jalbert; B Sele

1979-01-01

116

Human chromosome variation with two Robertsonian translocations  

Microsoft Academic Search

A woman was found to have 42 autosomes due to engagement of both chromosomes 14 in Robertsonian rearrangements, one with a chromosome 21 and the other with a chromosome 22: t(14q21q) and t(14q22q). The two translocations appear monocentric and by silver staining have no rRNA activity. The t(14q21q) translocation is familial and was ascertained through a nephew with Down syndrome,

Rodman Morgan; Helen Bixenman; Frederick Hecht

1985-01-01

117

Health risk assessment of the translocation of wild animals  

Microsoft Academic Search

Summary Potential health risks are always associated with the translocation of wild animals. A formal assessment of these health risks should be conducted in advance of each translocation, and the results of the risk assessment should be incorporated into decisions as to whether or not the translocation should occur or whether changes in the translocation protocol could substantially reduce health

F. A. Leighton

2002-01-01

118

Translocation of DNA across bacterial membranes.  

PubMed Central

DNA translocation across bacterial membranes occurs during the biological processes of infection by bacteriophages, conjugative DNA transfer of plasmids, T-DNA transfer, and genetic transformation. The mechanism of DNA translocation in these systems is not fully understood, but during the last few years extensive data about genes and gene products involved in the translocation processes have accumulated. One reason for the increasing interest in this topic is the discussion about horizontal gene transfer and transkingdom sex. Analyses of genes and gene products involved in DNA transfer suggest that DNA is transferred through a protein channel spanning the bacterial envelope. No common model exists for DNA translocation during phage infection. Perhaps various mechanisms are necessary as a result of the different morphologies of bacteriophages. The DNA translocation processes during conjugation, T-DNA transfer, and transformation are more consistent and may even be compared to the excretion of some proteins. On the basis of analogies and homologies between the proteins involved in DNA translocation and protein secretion, a common basic model for these processes is presented.

Dreiseikelmann, B

1994-01-01

119

Probiotic supplementation reduces the risk of bacterial translocation in experimental short bowel syndrome  

Microsoft Academic Search

Background\\/Purpose: Probiotics are live organisms that survive passage through the gastrointestinal tract and have beneficial effects on the host. Lactobacillus and Bifidobacterium have been recommended for cholesterol lowering, acute diarrhea, prevention of cancer, or inflammatory bowel disease. On the other hand, after massive bowel resection, bacterial overgrowth is frequent and favors bacterial translocation (BT). The possible beneficial effects of Bifidobacterium

I. Eizaguirre; N. Garcia Urkia; A. B. Asensio; I. Zubillaga; P. Zubillaga; C. Vidales; J. M. Garcia-Arenzana; P. Aldazabal

2002-01-01

120

Translocation involving 1p and 17q is a recurrent genetic alteration of human neuroblastoma cells  

SciTech Connect

Human neuroblastoma cells often are monosomic for the distal portion of 1p (1p36). The authors report that the deleted 1p material in cells of neuroblastoma lines is preferentially replaced by material from chromosome 17, resulting from an unbalanced 1;17 translocation. Chromosome 17 often acquires instability, followed by the integration of fragments into various marker chromosomes. As a consequence, 17q material can increase over 17p material. The nonrandom frequency of 1;17 translocations appears to indicate an as-yet-undefined contribution to neuroblastoma development. 35 refs., 4 figs., 1 tab.

Savelyeva, L.; Corvi, R.; Schwab, M. (German Cancer Research Center, Heidelberg (Germany))

1994-08-01

121

Laboratory evalution of a translocation double heterozygote for genetic control of Aedes aegypti.  

PubMed

Two pure translocation homozygote stocks, T1/T1 and T3/T3, were used to produce a double translocation heterozygote system designated T1/T3, employing T1/T1 as the male and T3/T3 as the female parent. The double heterozygote showed 73 % sterility when mated to wild females. Tests on mating competitiveness, recombination frequency in the differential segment, insemination rate and inheritance of sterility after release, for four generations in laboratory cages, have been carried out to evaluate the efficiency of this strain as an agent for a population control programme. PMID:24317745

Uppal, D K; Curtis, C F; Soni, V K

1978-07-01

122

Hanford Site background: Part 3, Groundwater background.  

National Technical Information Service (NTIS)

This report presents and interprets groundwater background data collected from the unconfined aquifer beneath the Hanford Site, a U.S. Department of Energy complex located near Richland, Washington. Characterization of background composition is an importa...

1997-01-01

123

Molecular studies of free and translocation trisomy  

SciTech Connect

Twenty cases of trisomy 13 were examined with molecular markers to determine the origin of the extra chromosome. Six cases had translocation trisomy: two de novo rob(13q;14q), one paternally derived rob(13q;14q), two de novo t(13q;13q), and one mosaic de novo t(13q;14q), one paternally derived rob(13q;14q), two de novo t(13q;13q), and one mosaic de novo t(13q;13q)r(13). Eighteen of nineteen informative patients were consistant with a maternal origin of the extra chromosome. Lack of a third allele at any locus in any of the three t(13q;13q) cases indicate that all were most likely isochromosomes of post-meiotic origin. In addition, two free trisomy cases were compatible with a somatic origin. Two mosaic free trisomy-13 cases, however, were both consistent with a maternal meiotic origin. The patient with a paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13;14) carrier and most trisomies are maternal in origin, this result should not be surprising; however it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. One balanced (non-trisomic) case with a non-mosaic 45,-13,-13,+t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologs, as has been found for all homologous Robertsonian translocations so far investigated. It is therefore also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. We cannot therefore infer anything about the origin of the chromosomes 13 and 14 involved in the two cases with de novo t(13q;14q) plus a maternally derived trisomy 13.

Robinson, W.P.; Bernasconi, F.; Lefort, G. [Univ. of Zuerich (Switzerland)] [and others

1994-09-01

124

Bacterial translocation: the influence of dietary variables.  

PubMed Central

Transmucosal passage of bacteria in critically ill patients may lead to a significant incidence of systemic sepsis. This has attracted much clinical interest, as it has been shown that malnutrition in itself, impairs various aspects of barrier function. Bacterial translocation is increased in animal models where nutrients are given by the parenteral route, while enteral feeding reverses this. Translocation is also considerably increased in response to a non-lethal endotoxin challenge, if there is pre-existing protein energy malnutrition. Similar results have been obtained where the insult is caused by the inflammatory agent, zymosan. Dietary fibre reduces the deleterious effects of either agent on translocation, although the type of fibre is important. Bulk forming but non-fermentable fibres are more effective than easily fermentable types (for example, pectin). Glutamine was not effective in preventing elemental diet induced bacterial translocation. Thus, although fermentable fibre and glutamine have positive effects on mucosal mass, they do not affect translocation. Enteral nutrition thus seems to be superior to parenteral nutrition in maintaining the functional barrier of the gut. A clearer understanding of the physiology of these effects may lead to use of specifically modified enteral diets in the critically ill patient. Images Figure 1

Deitch, E A

1994-01-01

125

Telomerase Deficiency Affects the Formation of Chromosomal Translocations by Homologous Recombination in Saccharomyces cerevisiae  

PubMed Central

Telomerase is a ribonucleoprotein complex required for the replication and protection of telomeric DNA in eukaryotes. Cells lacking telomerase undergo a progressive loss of telomeric DNA that results in loss of viability and a concomitant increase in genome instability. We have used budding yeast to investigate the relationship between telomerase deficiency and the generation of chromosomal translocations, a common characteristic of cancer cells. Telomerase deficiency increased the rate of formation of spontaneous translocations by homologous recombination involving telomere proximal sequences during crisis. However, telomerase deficiency also decreased the frequency of translocation formation following multiple HO-endonuclease catalyzed DNA double-strand breaks at telomere proximal or distal sequences before, during and after crisis. This decrease correlated with a sequestration of the central homologous recombination factor, Rad52, to telomeres determined by chromatin immuno-precipitation. This suggests that telomerase deficiency results in the sequestration of Rad52 to telomeres, limiting the capacity of the cell to repair double-strand breaks throughout the genome. Increased spontaneous translocation formation in telomerase-deficient yeast cells undergoing crisis is consistent with the increased incidence of cancer in elderly humans, as the majority of our cells lack telomerase. Decreased translocation formation by recombinational repair of double-strand breaks in telomerase-deficient yeast suggests that the reemergence of telomerase expression observed in many human tumors may further stimulate genome rearrangement. Thus, telomerase may exert a substantial effect on global genome stability, which may bear significantly on the appearance and progression of cancer in humans.

Meyer, Damon H.; Bailis, Adam M.

2008-01-01

126

Factors predisposing to adjacent 2 and 3:1 disjunctions: study of 161 human reciprocal translocations.  

PubMed Central

Reciprocal translocations produce imbalances by three types of disjunction which are, in decreasing frequency, adjacent 1, 3:1, and adjacent 2. Adjacent 1 disjunction produces duplication deficiencies of inverse topography to those of adjacent 2. The imbalanced chromosome segments in one of these types are balanced in the other. The disjunction 3:1 produces pure trisomies and monosomies. The following situations predispose to adjacent 2 disjunction: translocations between the long arms of two acrocentric chromosomes or between one of these and that of a No 9 chromosome; centric segments, either short or carrying a heterochromatic zone (9qh); a balanced translocation in the mother. The factors predisposing to the disjunction adjacent 2 operate by selection, or directly on the meiotic configuration. Some of them (shortness of the interstitial segment, shortness of the short arms of translocation chromosomes) act in both these ways. Their influence is probably responsible for the repetitive and exclusive character of this disjunction. The conditions for the occurrence of the 3:1 disjunctions seem less strict than those for adjacent 2, although they should be of the same nature (involvement of acrocentrics or a chromosome 9 in the translocation, maternal origin). Images

Jalbert, P; Sele, B

1979-01-01

127

Engineering human tumour-associated chromosomal translocations with the RNA-guided CRISPR-Cas9 system.  

PubMed

Cancer-related human chromosomal translocations are generated through the illegitimate joining of two non-homologous chromosomes affected by double-strand breaks (DSB). Effective methodologies to reproduce precise reciprocal tumour-associated chromosomal translocations are required to gain insight into the initiation of leukaemia and sarcomas. Here we present a strategy for generating cancer-related human chromosomal translocations in vitro based on the ability of the RNA-guided CRISPR-Cas9 system to induce DSBs at defined positions. Using this approach we generate human cell lines and primary cells bearing chromosomal translocations resembling those described in acute myeloid leukaemia and Ewing's sarcoma at high frequencies. FISH and molecular analysis at the mRNA and protein levels of the fusion genes involved in these engineered cells reveal the reliability and accuracy of the CRISPR-Cas9 approach, providing a powerful tool for cancer studies. PMID:24888982

Torres, R; Martin, M C; Garcia, A; Cigudosa, Juan C; Ramirez, J C; Rodriguez-Perales, S

2014-01-01

128

Analyzing disease risks associated with translocations.  

PubMed

Translocations of species are expected to be used increasingly to counter the undesirable effects of anthropogenic changes to ecosystems, including loss of species. Methods to assess the risk of disease associated with translocations have been compiled in a comprehensive manual of disease-risk analysis for movement of domestic animals. We used this manual to devise a qualitative method for assessing the probability of the occurrence of disease in wild animals associated with translocations. We adapted the method such that we considered a parasite (any agent of infectious or noninfectious disease) a hazard if it or the host had crossed an ecological or geographical barrier and was novel to the host. We included in our analyses hazards present throughout the translocation pathway derived from the interactions between host immunity and the parasite, the effect of parasites on populations, the effect of noninfectious disease agents, and the effect of stressors on host-parasite interactions. We used the reintroduction of Eurasian Cranes (Grus grus) to England to demonstrate our method. Of the 24 hazards identified, 1 was classified as high risk (coccidia) and 5 were medium risk (highly pathogenic avian influenza virus, Mycobacterium avium, Aspergillus fumigatus, tracheal worms [Syngamus sp. and Cyathostoma sp.], and Tetrameres spp.). Seventeen other hazards were considered low or very low risk. In the absence of better information on the number, identity, distribution, and pathogenicity of parasites of wild animals, there is uncertainty in the risk of disease to translocated animals and recipient populations. Surveys of parasites in source and destination populations and detailed health monitoring after release will improve the information available for future analyses of disease risk. We believe our method can be adapted to assess the risks of disease in other translocated populations. PMID:22533691

Sainsbury, Anthony W; Vaughan-Higgins, Rebecca J

2012-06-01

129

A recurrent translocation is mediated by homologous recombination between HERV-H elements  

PubMed Central

Background Chromosome rearrangements are caused by many mutational mechanisms; of these, recurrent rearrangements can be particularly informative for teasing apart DNA sequence-specific factors. Some recurrent translocations are mediated by homologous recombination between large blocks of segmental duplications on different chromosomes. Here we describe a recurrent unbalanced translocation casued by recombination between shorter homologous regions on chromosomes 4 and 18 in two unrelated children with intellectual disability. Results Array CGH resolved the breakpoints of the 6.97-Megabase (Mb) loss of 18q and the 7.30-Mb gain of 4q. Sequencing across the translocation breakpoints revealed that both translocations occurred between 92%-identical human endogenous retrovirus (HERV) elements in the same orientation on chromosomes 4 and 18. In addition, we find sequence variation in the chromosome 4 HERV that makes one allele more like the chromosome 18 HERV. Conclusions Homologous recombination between HERVs on the same chromosome is known to cause chromosome deletions, but this is the first report of interchromosomal HERV-HERV recombination leading to a translocation. It is possible that normal sequence variation in substrates of non-allelic homologous recombination (NAHR) affects the alignment of recombining segments and influences the propensity to chromosome rearrangement.

2012-01-01

130

Background removal procedure for rapid scan EPR  

Microsoft Academic Search

In rapid scan EPR the changing magnetic field creates a background signal with components at the scan frequency and its harmonics. The amplitude of the background signal increases with scan width and is more significant for weak EPR signals such as are obtained in the presence of magnetic field gradients. A procedure for distinguishing this background from the EPR signal

Mark Tseitlin; Tomasz Czechowski; Richard W. Quine; Sandra S. Eaton; Gareth R. Eaton

2009-01-01

131

Impaired DNA replication prompts deletions within palindromic sequences, but does not induce translocations in human cells  

PubMed Central

Palindromic regions are unstable and susceptible to deletion in prokaryotes and eukaryotes possibly due to stalled or slow replication. In the human genome, they also appear to become partially or completely deleted, while two palindromic AT-rich repeats (PATRR) contribute to known recurrent constitutional translocations. To explore the mechanism that causes the development of palindrome instabilities in humans, we compared the incidence of de novo translocations and deletions at PATRRs in human cells. Using a highly sensitive PCR assay that can detect single molecules, de novo deletions were detected neither in human somatic cells nor in sperm. However, deletions were detected at low frequency in cultured cell lines. Inhibition of DNA replication by administration of siRNA against the DNA polymerase alpha 1 (POLA1) gene or introduction of POLA inhibitors increased the frequency. This is in contrast to PATRR-mediated translocations that were never detected in similar conditions but were observed frequently in human sperm samples. Further deletions were found to take place during both leading- and lagging-strand synthesis. Our data suggest that stalled or slow replication induces deletions within PATRRs, but that other mechanisms might contribute to PATRR-mediated recurrent translocations in humans.

Kurahashi, Hiroki; Inagaki, Hidehito; Kato, Takema; Hosoba, Eriko; Kogo, Hiroshi; Ohye, Tamae; Tsutsumi, Makiko; Bolor, Hasbaira; Tong, Maoqing; Emanuel, Beverly S.

2009-01-01

132

Stat1 Nuclear Translocation by Nucleolin upon Monocyte Differentiation  

PubMed Central

Background Members of the signal transducer and activator of transcription (Stat) family of transcription factors traverse the nuclear membrane through a specialized structure, called the nuclear pore complex (NPC), which represents a selective filter for the import of proteins. Karyophilic molecules can bind directly to a subset of proteins of the NPC, collectively called nucleoporins. Alternatively, the transport is mediated via a carrier molecule belonging to the importin/karyopherin superfamily, which transmits the import into the nucleus through the NPC. Methodology/Principal Findings In this study, we provide evidence for an alternative Stat1 nuclear import mechanism, which is mediated by the shuttle protein nucleolin. We observed Stat1-nucleolin association, nuclear translocation and specific binding to the regulatory DNA element GAS. Using expression of nucleolin transgenes, we found that the nuclear localization signal (NLS) of nucleolin is responsible for Stat1 nuclear translocation. We show that this mechanism is utilized upon differentiation of myeloid cells and is specific for the differentiation step from monocytes to macrophages. Conclusions/Significance Our data add the nucleolin-Stat1 complex as a novel functional partner for the cell differentiation program, which is uniquely poised to regulate the transcription machinery via Stat1 and nuclear metabolism via nucleolin.

Jerke, Uwe; Tkachuk, Sergey; Kiyan, Julia; Stepanova, Victoria; Kusch, Angelika; Hinz, Michael; Dietz, Rainer; Haller, Hermann; Fuhrman, Bianca; Dumler, Inna

2009-01-01

133

Evidence for separate translocation pathways in determining cadmium accumulation in grain and aerial plant parts in rice  

PubMed Central

Background Cadmium (Cd) translocation and accumulation in the grain and aerial plant parts of rice (Oryza sativa L.) is an important aspect of food safety and phytoextraction in areas with contaminated soil. Because control of Cd translocation and accumulation is likely to be determined by the plants genetics, the Cd contents of grain and the aerial parts of rice may be manipulated to improve food safety and for phytoextraction ability. This study studied Cd translocation and accumulation and their genetic control in aerial parts of rice to provide a starting point for improving food safety and phytoextraction in Cd-contaminated soils. Results In the japonica rice cultivar "Nipponbare", Cd accumulated in leaves and culms until heading, and in culms and ears after heading. Two quantitative trait loci (QTLs) from indica cv. "Kasalath", qcd4-1 and qcd4-2, affect Cd concentrations in upper plant parts just before heading. Three near-isogenic lines (NILs) with qcd4-1 and qcd4-2 were selected from the "Nipponbare" background, and were analyzed for the effects of each QTL, and for interactions between the two QTLs. From the results compared between "Nipponbare" and each NIL, neither QTL influenced total Cd accumulation in aerial parts at 5 days after heading, but the interaction between two QTLs increased Cd accumulation. At 35 days after heading, qcd4-2 had increased Cd accumulation in the aerial plant parts and decreased translocation from leaves other than flag leaf, but interaction between the two QTLs increased translocation from leaves. NILqcd4-1,2 accumulated higher concentrations of Cd in brown rice than "Nipponbare". Conclusion Three types of Cd translocation and accumulation patterns demonstrated by NILs suggested that the accumulation of Cd in leaves and culms before heading, and translocation from them after heading are responsible for Cd accumulation in grain. Cd translocation from roots to culms and ears after heading may direct Cd to the aerial organs without influencing brown rice accumulation.

Kashiwagi, Takayuki; Shindoh, Kumiko; Hirotsu, Naoki; Ishimaru, Ken

2009-01-01

134

Improving the Efficiency of Mitotic Chromosome Analysis for Translocations.  

National Technical Information Service (NTIS)

The Heritable Translocation Assay (HTA) tests the offspring of treated male parents for heritable cytogenetic damage. Translocation heterozygotes (TH) can be ascertained by reduced fertility or sterility. During spermatogenesis, the meiotic chromosomes ca...

S. M. Morris

1981-01-01

135

Translocation pathways for inhaled asbestos fibers  

Microsoft Academic Search

We discuss the translocation of inhaled asbestos fibers based on pulmonary and pleuro-pulmonary interstitial fluid dynamics. Fibers can pass the alveolar barrier and reach the lung interstitium via the paracellular route down a mass water flow due to combined osmotic (active Na+ absorption) and hydraulic (interstitial pressure is subatmospheric) pressure gradient. Fibers can be dragged from the lung interstitium by

G Miserocchi; G Sancini; F Mantegazza; Gerolamo Chiappino

2008-01-01

136

Common Principles of Protein Translocation Across Membranes  

Microsoft Academic Search

Most major systems that transport proteins across a membrane share the following features: an amino-terminal transient signal sequence on the transported protein, a targeting system on the cis side of the membrane, a hetero-oligomeric transmembrane channel that is gated both across and within the plane of the membrane, a peripherally attached protein translocation motor that is powered by the hydrolysis

Gottfried Schatz; Bernhard Dobberstein

1996-01-01

137

Carbon and nitrogen translocation between seagrass ramets  

Microsoft Academic Search

The spatial scale and the magnitude of carbon and nitrogen translocation was examined in 5 tropical (Cymodocea serrulata, Halophila stipulacea, Halodule uninervis, Thalassodendron ciliatum, Thalassia hemprichii) and 3 temperate (Cymodocea nodosa, Posidonia oceanica, Zostera noltii) seagrass species using (13)Carbon (C-13) and 15 Nitrogen (N-15) as tracers in experiments conducted in situ, Seagrass leaf and rhizome production during the study period

N. Marbà; M. A. Hemminga; M. A. Mateo; C. M. Duarte; Y. E. M. Maas; J. Terrados; E. Gacia

2002-01-01

138

EF-G and EF4: translocation and back-translocation on the bacterial ribosome.  

PubMed

Ribosomes translate the codon sequence of an mRNA into the amino acid sequence of the corresponding protein. One of the most crucial events is the translocation reaction, which involves movement of both the mRNA and the attached tRNAs by one codon length and is catalysed by the GTPase elongation factor G (EF-G). Interestingly, recent studies have identified a structurally related GTPase, EF4, that catalyses movement of the tRNA2-mRNA complex in the opposite direction when the ribosome stalls, which is known as back-translocation. In this Review, we describe recent insights into the mechanistic basis of both translocation and back-translocation. PMID:24362468

Yamamoto, Hiroshi; Qin, Yan; Achenbach, John; Li, Chengmin; Kijek, Jaroslaw; Spahn, Christian M T; Nierhaus, Knud H

2014-02-01

139

Polynomial-time Algorithm for Computing Translocation Distance Between Genomes  

Microsoft Academic Search

this paper we study the translocation distance problem,modeling the evolution of genomes evolving by translocations.Translocation distance problem was recently studied for the firsttime by Kececioglu and Ravi, who gave a 2-approximation algorithmfor computing translocation distance. In this paper we provea duality theorem leading to a polynomial time algorithm for computingtranslocation distance for the case when the orientation ofthe genes are

Sridhar Hannenhalli

1996-01-01

140

Infertility in human males with autosomal translocations: meiotic study of a 14;22 Robertsonian translocation  

Microsoft Academic Search

Pachytene analysis was undertaken in a male patient heterozygous for a 14q22q Robertsonian translocation. The relatively low rate of XY autosome association led us to examine the relationships existing between the chromosomes involved in the translocation, the rate of XY-autosome association and the degree of spermatogenic failure. Cytogenetic investigations in infertile men and the results of the meiotic studies suggest

M. R. Guichaoua; B. Quack; R. M. Speed; B. Noel; A. C. Chandley; J. M. Luciani

1990-01-01

141

Geographic Translocation of Bats: Known and Potential Problems  

PubMed Central

Natural, accidental, and intentional translocation of bats, both intra- and intercontinentally, has been documented. Some bats have been translocated while incubating infectious diseases, including rabies or related lyssavirus infections; others have escaped confinement en route to or at their destinations, while others have been released deliberately. Known events and potential consequences of bat translocation are reviewed, including a proposed solution to the attendant problems.

2003-01-01

142

Analyse Statistique d'Une Base de Donnees de Translocations Reciproques (Statistical Analysis of a Reciprocal Translocations Data Base).  

National Technical Information Service (NTIS)

Attempts made in using logistical regression analysis to predict the nonalternative segregation of the chromosomes of couples carrying reciprocal translocation babies are reported. One out of 600 babies have a reciprocal translocation which results in an ...

C. Cans O. Cohen C. Lavergne

1992-01-01

143

Mutant Huntingtin: Nuclear translocation and cytotoxicity mediated by GAPDH  

PubMed Central

The pathophysiology of Huntington’s disease reflects actions of mutant Huntingtin (Htt) (mHtt) protein with polyglutamine repeats, whose N-terminal fragment translocates to the nucleus to elicit neurotoxicity. We establish that the nuclear translocation and associated cytotoxicity of mHtt reflect a ternary complex of mHtt with GAPDH and Siah1, a ubiquitin-E3-ligase. Overexpression of GAPDH or Siah1 enhances nuclear translocation of mHtt and cytotoxicity, whereas GAPDH mutants that cannot bind Siah1 prevent translocation. Depletion of GAPDH or Siah1 by RNA interference diminishes nuclear translocation of mHtt.

Bae, Byoung-Il; Hara, Makoto R.; Cascio, Matthew B.; Wellington, Cheryl L.; Hayden, Michael R.; Ross, Christopher A.; Ha, Hyo Chol; Li, Xiao-Jiang; Snyder, Solomon H.; Sawa, Akira

2006-01-01

144

A Novel de novo Balanced Reciprocal Translocation t(18;22) Associated with Recurrent Miscarriages: A Case Report  

PubMed Central

Background Recurrent miscarriage is a major concern in the couples with reproductive problems. The chromosomal abnormalities, mainly balanced rearrangements are reported in variable phenotypes and the prevalence of them is 2-8% in such couples. Case Presentation In this study, the clinical, cytogenetic and molecular cytogenetic evaluations were performed on a couple with RM. The cytogenetic analysis of the husband revealed a balanced reciprocal translocation of t(18;22)(q21.1;q12) whereas wife had a normal karyotype of 46,XX. Further spectral karyotyping was performed to rule out the involvement of any other chromosomal aberrations present in the genome. Additional whole chromosome paint FISH (Fluorescence in situ hybridization) with paint probes 18 and 22 confirmed the translocation. Conclusion To our knowledge, this is the first report of a novel (18;22) translocation with unique breakpoints and their association with RM. The reciprocal translocations provide a good opportunity for the identification of disease associated genes. However, in recurrent miscarriages, most of them do not disrupt any gene at the breakpoint but can lead to unbalanced gametes and hence poor reproductive outcome like RM or birth of a child with malformations and intellectual disability. The translocation breakpoints might be risk factors for RM. Moreover, the impact of the balanced translocations in association with RM is discussed in this report.

Dutta, Usha R.; Ponnala, Rajitha; Dalal, Ashwin

2014-01-01

145

Stiff filamentous virus translocations through solid-state nanopores.  

PubMed

The ionic conductance through a nanometer-sized pore in a membrane changes when a biopolymer slides through it, making nanopores sensitive to single molecules in solution. Their possible use for sequencing has motivated numerous studies on how DNA, a semi-flexible polymer, translocates nanopores. Here we study voltage-driven dynamics of the stiff filamentous virus fd with experiments and simulations to investigate the basic physics of polymer translocations. We find that the electric field distribution aligns an approaching fd with the nanopore, promoting its capture, but it also pulls fd sideways against the membrane after failed translocation attempts until thermal fluctuations reorient the virus for translocation. fd is too stiff to translocate in folded configurations. It therefore translocates linearly, exhibiting a voltage-independent mobility and obeying first-passage-time statistics. Surprisingly, lengthwise Brownian motion only partially accounts for the translocation velocity fluctuations. We also observe a voltage-dependent contribution whose origin is only partially determined. PMID:24932700

McMullen, Angus; de Haan, Hendrick W; Tang, Jay X; Stein, Derek

2014-01-01

146

Translocation of Thorotrast in the body.  

PubMed

To investigate whether there is a permanent translocation of Thorotrast in the body, the liver of male Lewis rats was removed 4 weeks after injection of Thorotrast (300 microliters) and replaced by a donor liver. In half of the animals the spleen was removed as well. Measuring the 232Th content in the donor liver at different times after implantation demonstrated a permanent transport of 232Th into the surrogate organ. After 231 days a 232Th depot of about 1.1 mg was found, representing about 3% of the total body burden. The additional removal of the spleen resulted in a significantly lower transport of 232Th into the implanted liver. Histological examinations of the donated livers revealed increasing local concentration of Thorotrast granules, leading to the development of conglomerates. A comparable translocation of Thorotrast was verified in two humans who required liver transplantation more than 40 years after Thorotrast injection. PMID:8184016

Spiethoff, A; Wesch, H; Wegener, K; Hanisch, E; Kaul, A

1994-06-01

147

Origin of translocation barriers for polyelectrolyte chains  

PubMed Central

For single-file translocations of a charged macromolecule through a narrow pore, the crucial step of arrival of an end at the pore suffers from free energy barriers, arising from changes in intrachain electrostatic interaction, distribution of ionic clouds and solvent molecules, and conformational entropy of the chain. All contributing factors to the barrier in the initial stage of translocation are evaluated by using the self-consistent field theory for the polyelectrolyte and the coupled Poisson–Boltzmann description for ions without radial symmetry. The barrier is found to be essentially entropic due to conformational changes. For moderate and high salt concentrations, the barriers for the polyelectrolyte chain are quantitatively equivalent to that of uncharged self-avoiding walks. Electrostatic effects are shown to increase the free energy barriers, but only slightly. The degree of ionization, electrostatic interaction strength, decreasing salt concentration, and the solvent quality all result in increases in the barrier.

Kumar, Rajeev; Muthukumar, M.

2009-01-01

148

Regulating DNA translocation through functionalized soft nanopores  

NASA Astrophysics Data System (ADS)

Nanopores have emerged as promising next-generation devices for DNA sequencing technology. The two major challenges in such devices are: (i) find an efficient way to raise the DNA capture rate prior to funnelling a nanopore, and (ii) reduce the translocation velocity inside it so that single base resolution can be attained efficiently. To achieve these, a novel soft nanopore comprising a solid-state nanopore and a functionalized soft layer is proposed to regulate the DNA electrokinetic translocation. We show that, in addition to the presence of an electroosmotic flow (EOF), which reduces the DNA translocation velocity, counterion concentration polarization (CP) occurs near the entrance of the nanopore. The latter establishes an enrichment of the counterion concentration field, thereby electrostatically enhancing the capture rate. The dependence of the ionic current on the bulk salt concentration, the soft layer properties, and the length of the nanopore are investigated. We show that if the salt concentration is low, the ionic current depends largely upon the length of the nanopore, and the density of the fixed charge of the soft layer, but not upon its degree of softness. On the other hand, if it is high, ionic current blockade always occurs, regardless of the levels of the other parameters. The proposed soft nanopore is capable of enhancing the performance of DNA translocation while maintaining its basic signature of the ionic current at high salt concentration. The results gathered provide the necessary information for designing devices used in DNA sequencing.Nanopores have emerged as promising next-generation devices for DNA sequencing technology. The two major challenges in such devices are: (i) find an efficient way to raise the DNA capture rate prior to funnelling a nanopore, and (ii) reduce the translocation velocity inside it so that single base resolution can be attained efficiently. To achieve these, a novel soft nanopore comprising a solid-state nanopore and a functionalized soft layer is proposed to regulate the DNA electrokinetic translocation. We show that, in addition to the presence of an electroosmotic flow (EOF), which reduces the DNA translocation velocity, counterion concentration polarization (CP) occurs near the entrance of the nanopore. The latter establishes an enrichment of the counterion concentration field, thereby electrostatically enhancing the capture rate. The dependence of the ionic current on the bulk salt concentration, the soft layer properties, and the length of the nanopore are investigated. We show that if the salt concentration is low, the ionic current depends largely upon the length of the nanopore, and the density of the fixed charge of the soft layer, but not upon its degree of softness. On the other hand, if it is high, ionic current blockade always occurs, regardless of the levels of the other parameters. The proposed soft nanopore is capable of enhancing the performance of DNA translocation while maintaining its basic signature of the ionic current at high salt concentration. The results gathered provide the necessary information for designing devices used in DNA sequencing. Electronic supplementary information (ESI) available: Details of the theoretical derivation, numerical implementation, code validation, and the results of the normalized DNA translational velocity for the case of Fig. 5. See DOI: 10.1039/c2nr30102d

Yeh, Li-Hsien; Zhang, Mingkan; Qian, Shizhi; Hsu, Jyh-Ping

2012-03-01

149

Simulation of polymer translocation through protein channels  

NASA Astrophysics Data System (ADS)

A modeling algorithm is presented to compute simultaneously polymer conformations and ionic current, as single polymer molecules undergo translocation through protein channels. The method is based on a combination of Langevin dynamics for coarse-grained models of polymers and the Poisson-Nernst-Planck formalism for ionic current. For the illustrative example of ssDNA passing through the -hemolysin pore, vivid details of conformational fluctuations of the polymer inside the vestibule and -barrel compartments of the protein pore, and their consequent effects on the translocation time and extent of blocked ionic current are presented. In addition to yielding insights into several experimentally reported puzzles, our simulations offer experimental strategies to sequence polymers more efficiently.

Muthukumar, M.; Kong, C. Y.

2006-04-01

150

Immunohistochemical screening and fluorescence in situ hybridization confirmation of ALK translocation in lung adenocarcinoma and its clinicopathological significance: a single-center large-scale investigation of Chinese patients.  

PubMed

Anaplastic lymphoma kinase (ALK) translocation-positive adenocarcinoma of the lung is a newly recognized molecular subgroup. Limited data on the clinicopathological features of this entity in the Chinese population are available. We performed immunohistochemical staining for the ALK protein and fluorescence in situ hybridization detection of the ALK translocation. We enrolled 793 Chinese patients with lung adenocarcinoma and identified 54 ALK translocation-positive patients (6.8%) in the group. Compared with the entire group of patients, ALK translocation-positive patients were younger (P < .01) and more likely to be nonsmokers (P = .017), but presented with a higher percentage of advanced-stage disease (P = .022) and lymph node metastases (P = .006). ALK translocation-positive patients more commonly exhibited poorly differentiated tumor histology and a predominantly solid tumor growth pattern relative to the ALK translocation-negative patients. Morphologically, ALK translocation was associated with extracellular mucus secretion, a mucinous cribriform structure, and signet ring cell (SRC) components. ALK translocation was present in 42.5% and 34.0% of adenocarcinomas with SRC components or wild-type EGFR, respectively. ALK translocation, occurring at a frequency of 6.8% in Chinese patients, defines a unique molecular subgroup of lung tumors. Fluorescence in situ hybridization should be performed in each case of lung adenocarcinoma with SRC components or wild-type EGFR to identify ALK translocation-positive patients. PMID:24775606

Wang, Wei-Ya; Liang, Dong-Ni; Yao, Wen-Qing; Wu, Wei-Lu; Li, Jin-Nan; Chen, Min; Liao, Dian-Ying; Zhang, Mei; Li, Gan-di

2014-07-01

151

Incontinentia pigmenti and X-autosome translocations  

Microsoft Academic Search

Incontinentia pigmenti (IP) is a rare X-linked disease with marked female-to-female transmission and a dominant pattern of inheritance. Reports of six unrelated females with IP and X-autosomal translocations, all with the X breakpoint at Xp11, and an additional report of a female with IP and a 45,X\\/46,X,r(X) karyotype suggests that this may be the locus for the IP gene. When

John A. Crolla; Simone Gilgenkrantz; Jean de Grouchy; Tadashi Kajii; Martin Bobrow

1989-01-01

152

Extremely low frequency magnetic fields in residences in Germany. Distribution of measurements, comparison of two methods for assessing exposure, and predictors for the occurrence of magnetic fields above background level  

Microsoft Academic Search

We examined the results of 1,835 magnetic field measurements in German residences conducted between November 1997 and September\\u000a 1999. The measurements were part of an epidemiological study on the relationship between magnetic fields and childhood leukemia.\\u000a We performed a fixed-location measurement of the magnetic field at 50 Hz and 16 2\\/3 Hz (frequency of the German railway system)\\u000a over 24

Joachim Schüz; Jan-Peter Grigat; Bernd Störmer; Gerd Rippin; Karl Brinkmann; Jörg Michaelis

2000-01-01

153

Electrokinetic particle translocation through a nanopore.  

PubMed

Nanoparticle electrophoretic translocation through a single nanopore induces a detectable change in the ionic current, which enables the nanopore-based sensing for various bio-analytical applications. In this study, a transient continuum-based model is developed for the first time to investigate the electrokinetic particle translocation through a nanopore by solving the Nernst-Planck equations for the ionic concentrations, the Poisson equation for the electric potential and the Navier-Stokes equations for the flow field using an arbitrary Lagrangian-Eulerian (ALE) method. When the applied electric field is relatively low, a current blockade is expected. In addition, the particle could be trapped at the entrance of the nanopore when the electrical double layer (EDL) adjacent to the charged particle is relatively thick. When the electric field imposed is relatively high, the particle can always pass through the nanopore by electrophoresis. However, a current enhancement is predicted if the EDL of the particle is relatively thick. The obtained numerical results qualitatively agree with the existing experimental results. It is also found that the initial orientation of the particle could significantly affect the particle translocation and the ionic current through a nanopore. Furthermore, a relatively high electric field tends to align the particle with its longest axis parallel to the local electric field. However, the particle's initial lateral offset from the centerline of the nanopore acts as a minor effect. PMID:21229154

Ai, Ye; Qian, Shizhi

2011-03-01

154

Iron translocation by free fatty acids.  

PubMed Central

Organic extracts of cigarette smoke and uncombusted tobacco contain substances capable of translocating iron from aqueous solutions into immiscible organic solvents. Such extracts will also effect the organic solvation of iron present in ferruginous forms of asbestos such as amosite and crocidolite (Qian and Eaton, Arch Biochem Biophys 1989, 275:280). These substances, previously detected by their iron-translocating properties, have now been purified and identified by mass spectroscopy as saturated fatty acids, predominantly stearic and palmitic acids. Organic extracts of tobacco smoke, as well as the pure fatty acids, also transfer ferrous iron into both isolated red cell membranes and intact human erythrocytes. The increased membrane iron may enhance cellular susceptibility to exogenous oxidants; erythrocyte membranes subject to fatty acid-mediated iron accumulation show elevated peroxidation of endogenous polyunsaturated fatty acids. These observations may help explain the phlogistic effects of tobacco use and suggest, in a broader context, that free fatty acids may act as physiologic and pathologic mediators of metal translocation.

Qian, M. W.; Eaton, J. W.

1991-01-01

155

The Cosmological Background Radiation  

Microsoft Academic Search

This book provides an introduction to the physics, astrophysics and cosmology of the cosmic microwave background radiation. Adopting the Standard Big Bang model of the universe, the authors cover topics including the origin of the background, intrinsic fluctuations, and the universe and background radiation after recombination. Finally they present measurement of the radiation and its anisotropies, along with a review

Marc Lachièze-Rey; Edgard Gunzig

1999-01-01

156

Translocation capture sequencing: a method for high throughput mapping of chromosomal rearrangements.  

PubMed

Chromosomal translocations require formation and joining of DNA double strand breaks (DSBs). These events disrupt the integrity of the genome and are involved in producing leukemias, lymphomas and sarcomas. Translocations are frequent, clonal and recurrent in mature B cell lymphomas, which bear a particularly high DNA damage burden by virtue of activation-induced cytidine deaminase (AID) expression. Despite the ubiquity of genomic rearrangements, the forces that underlie their genesis are not well understood. Here, we provide a detailed description of a new method for studying these events, translocation capture sequencing (TC-Seq). TC-Seq provides the means to document chromosomal rearrangements genome-wide in primary cells, and to discover recombination hotspots. Demonstrating its effectiveness, we successfully estimate the frequency of c-myc/IgH translocations in primary B cells, and identify hotspots of AID-mediated recombination. Furthermore, TC-Seq can be adapted to generate genome-wide rearrangement maps in any cell type and under any condition. PMID:22033343

Oliveira, Thiago Y; Resch, Wolfgang; Jankovic, Mila; Casellas, Rafael; Nussenzweig, Michel C; Klein, Isaac A

2012-01-31

157

Breakpoint Mapping and Array CGH in Translocations: Comparison of a Phenotypically Normal and an Abnormal Cohort  

PubMed Central

We report the analyses of breakpoints in 31 phenotypically normal and 14 abnormal carriers of balanced translocations. Our study assesses the differences between balanced translocations in normal carriers and those in abnormal carriers, focusing on the presence of genomic imbalances at the breakpoints or elsewhere in the genome, presence of cryptic chromosome rearrangements, and gene disruption. Our hypothesis is that all four features will be associated with phenotypic abnormalities and absent or much less frequent in a normal population. In the normal cohort, we identified neither genomic imbalances at the breakpoints or elsewhere in the genome nor cryptic chromosome rearrangements. In contrast, we identified candidate disease-causing imbalances in 4/14 abnormal patients. These were three breakpoint associated deletions and three deletions unrelated to the breakpoints. All six de novo deletions originated on the paternally inherited chromosome. Additional complexity was also present in one of these cases. Gene disruption by the breakpoints was present in 16/31 phenotypically normal individuals and in 5/14 phenotypically abnormal patients. Our results show that translocations in phenotypically abnormal patients are molecularly distinct from those in normal individuals: the former are more likely to be associated with genomic imbalances at the breakpoints or elsewhere and with chromosomal complexity, whereas the frequency of gene disruption is similar in both normal and abnormal translocation carriers.

Baptista, Julia; Mercer, Catherine; Prigmore, Elena; Gribble, Susan M.; Carter, Nigel P.; Maloney, Viv; Thomas, N. Simon; Jacobs, Patricia A.; Crolla, John A.

2008-01-01

158

Prompt colonization of the hepaticojejunostomy and translocation of bacteria to liver after bile duct reconstruction  

Microsoft Academic Search

Background\\/Purpose: Ascending cholangitis is one of the most common and earliest complications after bile duct reconstruction (BDR), particularly in patients with biliary atresia. To elucidate if the local factors such as the hepaticoje-junostomy (HPJ) was responsible for the infection and the level of HPJ would affect the incidence of bacterial translocation (BT) to liver, this study was conducted.Methods: Fourteen piglets

Jiin-Haur Chuang; Wei-Jen Chen; Shin-Yi Lee; Nyuk-Kong Chang

1998-01-01

159

Macular translocation with 360° retinotomy for management of retinal pigment epithelial tear: long-term results  

Microsoft Academic Search

BackgroundTo determine long-term functional and morphological changes after full macular translocation (FMT) with 360° retinotomy in patients with retinal pigment epithelium (RPE) tears, in light of the increasing number of reports of this complication following vascular endothelial growth factor (VEGF)-modulating therapy.MethodsWe retrospectively reviewed a consecutive series of six patients with RPE tears secondary to neovascular age-related macular degeneration who underwent

A. Polito; M. Cereda; F. Romanelli; G. Pertile

2010-01-01

160

Improvement in near visual function after macular translocation surgery with 360-degree peripheral retinectomy  

Microsoft Academic Search

Background Information is limited on how specific near-vision skills are impacted by therapies such as macular translocation surgery with 360-degree retinectomy (MT360) for age-related macular degeneration (AMD). Methods Standardized tests of near vision were given to 25 consecutive patients with AMD who met entry criteria for this study, preoperatively and 6 and 12 months after MT360. Tests included: near acuity

Cynthia A. Toth; Deborah J. Lapolice; Avie D. Banks; Sandra S. Stinnett

2004-01-01

161

Probiotics prevent bacterial translocation and improve intestinal barrier function in rats following chronic psychological stress  

PubMed Central

Background and aim Chronic psychological stress, including water avoidance stress (WAS), induces intestinal mucosal barrier dysfunction and impairs mucosal defences against luminal bacteria. The aim of this study was to determine the ability of a defined probiotic regimen to prevent WAS induced intestinal pathophysiology. Methods Male rats were subjected to either WAS or sham stress for one hour per day for 10 consecutive days. Additional animals received seven days of Lactobacillus helveticus and L rhamnosus in the drinking water prior to stress and remained on these probiotics for the duration of the study. Rats were then sacrificed, intestinal segments assessed in Ussing chambers, and mesenteric lymph nodes cultured to determine bacterial translocation. Results All animals remained healthy for the duration of the study. Chronic WAS induced excess ion secretion (elevated baseline short circuit current) and barrier dysfunction (increased conductance) in both the ileum and colon, associated with increased bacterial adhesion and penetration into surface epithelial cells. Approximately 70% of rats subjected to WAS had bacterial translocation to mesenteric lymph nodes while there was no bacterial translocation in controls. Probiotic pretreatment alone had no effect on intestinal barrier function. However, WAS induced increased ileal short circuit current was reduced with probiotics whereas there was no impact on altered conductance. Pretreatment of animals with probiotics also completely abrogated WAS induced bacterial adhesion and prevented translocation of bacteria to mesenteric lymph nodes. Conclusion These findings indicate that probiotics can prevent chronic stress induced intestinal abnormalities and, thereby, exert beneficial effects in the intestinal tract.

Zareie, M; Johnson-Henry, K; Jury, J; Yang, P-C; Ngan, B-Y; McKay, D M; Soderholm, J D; Perdue, M H; Sherman, P M

2006-01-01

162

Fibroblast growth factor receptor 2 translocations in intrahepatic cholangiocarcinoma.  

PubMed

Patients with cholangiocarcinoma often present with locally advanced or metastatic disease. There is a need for effective therapeutic strategies for advanced stage cholangiocarcinoma. Recently, FGFR2 translocations have been identified as a potential target for tyrosine kinase inhibitor therapies. This study evaluated 152 cholangiocarcinomas and 4 intraductal papillary biliary neoplasms of the bile duct for presence of FGFR2 translocations by fluorescence in situ hybridization and characterized the clinicopathologic features of cases with FGFR2 translocations. Thirteen (10 women, 3 men; 8%) of 156 biliary tumors harbored FGFR2 translocations, including 12 intrahepatic cholangiocarcinomas (12/96; 13%) and 1 intraductal papillary neoplasm of the bile duct. Histologically, cholangiocarcinomas with FGFR2 translocations displayed prominent intraductal growth (62%) or anastomosing tubular glands with desmoplasia (38%). Immunohistochemically, the tumors with FGFR2 translocations frequently showed weak and patchy expression of CK19 (77%). Markers of the stem cell phenotype in cholangiocarcinoma, HepPar1 and CK20, were negative in all cases. The median cancer-specific survival for patients whose tumors harbored FGFR2 translocations was 123 months compared to 37 months for cases without FGFR2 translocations (P = .039). This study also assessed 100 cholangiocarcinomas for ERBB2 amplification and ROS1 translocations. Of the cases tested, 3% and 1% were positive for ERBB2 amplification and ROS1 translocation, respectively. These results confirm that FGFR2, ERRB2, and ROS1 alterations are potential therapeutic targets for intrahepatic cholangiocarcinoma. PMID:24837095

Graham, Rondell P; Barr Fritcher, Emily G; Pestova, Ekaterina; Schulz, John; Sitailo, Leonid A; Vasmatzis, George; Murphy, Stephen J; McWilliams, Robert R; Hart, Steven N; Halling, Kevin C; Roberts, Lewis R; Gores, Gregory J; Couch, Fergus J; Zhang, Lizhi; Borad, Mitesh J; Kipp, Benjamin R

2014-08-01

163

The effect of glucagon-like peptide 2 on intestinal permeability and bacterial translocation in acute necrotizing pancreatitis  

Microsoft Academic Search

Background: Acute pancreatitis (AP) initiates a generalized inflammatory response that increases intestinal permeability and promotes bacterial translocation (BT). Impairment of the intestinal epithelial barrier is known to promote BT. Glucagon-like peptide 2 (GLP-2), a 33 residue peptide hormone, is a key regulator of the intestinal mucosa by stimulating epithelial growth. The purpose of this study was to determine whether GLP-2

George J Kouris; Qiang Liu; H Rossi; Goldie Djuricin; Paulo Gattuso; C Nathan; Robert A Weinstein; Richard A Prinz

2001-01-01

164

Background Removal Procedure for Rapid Scan EPR  

PubMed Central

In rapid scan EPR the changing magnetic field creates a background signal with components at the scan frequency and its harmonics. The amplitude of the background signal increases with scan width and is more significant for weak EPR signals such as are obtained in the presence of magnetic field gradients. A procedure for distinguishing this background from the EPR signal is proposed, mathematically described, and tested for various experimental conditions.

Tseitlin, Mark; Czechowski, Tomasz; Quine, Richard W.; Eaton, Sandra S.; Eaton, Gareth R.

2009-01-01

165

The Cosmic Background Explorer.  

ERIC Educational Resources Information Center

Outlines the Cosmic Background Explorer (COBE) mission to measure celestial radiation. Describes the instruments used and experiments involving differential microwave radiometers, and a far infrared absolute spectrophotometer. (YP)

Gulkis, Samuel; And Others

1990-01-01

166

Millisecond dynamics of RNA polymerase II translocation at atomic resolution  

PubMed Central

Transcription is a central step in gene expression, in which the DNA template is processively read by RNA polymerase II (Pol II), synthesizing a complementary messenger RNA transcript. At each cycle, Pol II moves exactly one register along the DNA, a process known as translocation. Although X-ray crystal structures have greatly enhanced our understanding of the transcription process, the underlying molecular mechanisms of translocation remain unclear. Here we use sophisticated simulation techniques to observe Pol II translocation on a millisecond timescale and at atomistic resolution. We observe multiple cycles of forward and backward translocation and identify two previously unidentified intermediate states. We show that the bridge helix (BH) plays a key role accelerating the translocation of both the RNA:DNA hybrid and transition nucleotide by directly interacting with them. The conserved BH residues, Thr831 and Tyr836, mediate these interactions. To date, this study delivers the most detailed picture of the mechanism of Pol II translocation at atomic level.

Silva, Daniel-Adriano; Weiss, Dahlia R.; Pardo Avila, Fatima; Da, Lin-Tai; Levitt, Michael; Wang, Dong; Huang, Xuhui

2014-01-01

167

Conductivity in an anisotropic background  

SciTech Connect

By using the gauge/gravity duality, we investigate the dual field theories of the anisotropic backgrounds, which are exact solutions of Einstein-Maxwell-dilaton theory with a Liouville potential. When we turn on the bulk gauge field fluctuation A{sub x} with a nontrivial dilaton coupling, the AC conductivity of this dual field theory is proportional to the frequency with an exponent depending on parameters of the anisotropic background. In some parameter regions, we find that this conductivity can have the negative exponent like the strange metal. In addition, we also investigate another U(1) gauge field fluctuation, which is not coupled with a dilaton field. We classify all possible conductivities of this system and find that the exponent of the conductivity is always positive.

Lee, Bum-Hoon [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Center for Quantum Spacetime (CQUeST), Sogang University, Seoul 121-742 (Korea, Republic of); Nam, Siyoung [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Pang, Da-Wei; Park, Chanyong [Center for Quantum Spacetime (CQUeST), Sogang University, Seoul 121-742 (Korea, Republic of)

2011-03-15

168

Bacterial translocation after cold stress in young and old mice.  

PubMed

Spontaneous translocation of the normal intestinal flora was observed in higher rate in old mice being in a state of thymus involution than in young ones. The proportion of bacterial translocation 24 and 48 h after cold stress increased in both young and old mice, the increase of translocation as compared to controls was larger in case of young mice than in old ones. The distribution of isolated bacterial strains according to Gram stain also differed in young and old groups. PMID:2100901

Anderlik, P; Szeri, I; Bános, Z; Barna, Z

1990-01-01

169

Iron uptake and translocation by macrocystis pyrifera  

SciTech Connect

Parameters of iron uptake have been determined for blade tissue of Macrocystis pyrifera (L.) C. Ag. These include the effects of iron concentration, light, various inhibitors, and blade type. All experiments were conducted in the defined artificial seawater Aquil. Iron uptake is light independent, energy dependent, and dependent on the reduction from Fe/sup 3+/ to Fe/sup 2+/. Iron is concentrated in the sieve tube exudate; exudate analysis revealed the presence of other micronutrients. Iron and other micronutrient translocation is discussed.

Manley, S.L.

1981-10-01

170

Microbial Translocation Across the GI Tract*  

PubMed Central

The lumen of the gastrointestinal (GI) tract is home to an enormous quantity of different bacterial species, our microbiota, that thrive in an often symbiotic relationship with the host. Given that the healthy host must regulate contact between the microbiota and its immune system to avoid overwhelming systemic immune activation, humans have evolved several mechanisms to attenuate systemic microbial translocation (MT) and its consequences. However, several diseases are associated with the failure of one or more of these mechanisms, with consequent immune activation and deleterious effects on health. Here, we discuss the mechanisms underlying MT, diseases associated with MT, and therapeutic interventions that aim to decrease it.

Brenchley, Jason M.; Douek, Daniel C.

2012-01-01

171

Molecular motors for DNA translocation in prokaryotes  

PubMed Central

DNA transport is an essential life process. From chromosome separation during cell division or sporulation, to DNA virus ejection or encapsidation, to horizontal gene transfer, it is ubiquitous in all living organisms. Directed DNA translocation is often energetically unfavorable and requires an active process that uses energy, namely the action of molecular motors. In this review we present recent advances in the understanding of three molecular motors involved in DNA transport in prokaryotes, paying special attention to recent studies using single-molecule techniques. We first discuss DNA transport during cell division, then packaging of DNA in phage capsids, and then DNA import during bacterial transformation.

Allemand, Jean-Francois; Maier, Berenike; Smith, Douglas E.

2012-01-01

172

Correlators in nontrivial backgrounds  

SciTech Connect

Operators in N=4 super Yang-Mills theory with an R-charge of O(N{sup 2}) are dual to backgrounds which are asymtotically AdS{sub 5}xS{sup 5}. In this article we develop efficient techniques that allow the computation of correlation functions in these backgrounds. We find that (i) contractions between fields in the string words and fields in the operator creating the background are the field theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free field theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations.

Mello Koch, Robert de [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa); Stellenbosch Institute for Advanced Studies, Stellenbosch (South Africa); Ives, Norman; Stephanou, Michael [National Institute for Theoretical Physics, Department of Physics and Centre for Theoretical Physics, University of the Witwatersrand, Wits, 2050 (South Africa)

2009-01-15

173

A translocation motif in relaxase TrwC specifically affects recruitment by its conjugative type IV secretion system.  

PubMed

Type IV secretion system (T4SS) substrates are recruited through a translocation signal that is poorly defined for conjugative relaxases. The relaxase TrwC of plasmid R388 is translocated by its cognate conjugative T4SS, and it can also be translocated by the VirB/D4 T4SS of Bartonella henselae, causing DNA transfer to human cells. In this work, we constructed a series of TrwC variants and assayed them for DNA transfer to bacteria and human cells to compare recruitment requirements by both T4SSs. Comparison with other reported relaxase translocation signals allowed us to determine two putative translocation sequence (TS) motifs, TS1 and TS2. Mutations affecting TS1 drastically affected conjugation frequencies, while mutations affecting either motif had only a mild effect on DNA transfer rates through the VirB/D4 T4SS of B. henselae. These results indicate that a single substrate can be recruited by two different T4SSs through different signals. The C terminus affected DNA transfer rates through both T4SSs tested, but no specific sequence requirement was detected. The addition of a Bartonella intracellular delivery (BID) domain, the translocation signal for the Bartonella VirB/D4 T4SS, increased DNA transfer up to 4% of infected human cells, providing an excellent tool for DNA delivery to specific cell types. We show that the R388 coupling protein TrwB is also required for this high-efficiency TrwC-BID translocation. Other elements apart from the coupling protein may also be involved in substrate recognition by T4SSs. PMID:23995644

Alperi, Anabel; Larrea, Delfina; Fernández-González, Esther; Dehio, Christoph; Zechner, Ellen L; Llosa, Matxalen

2013-11-01

174

A Translocation Motif in Relaxase TrwC Specifically Affects Recruitment by Its Conjugative Type IV Secretion System  

PubMed Central

Type IV secretion system (T4SS) substrates are recruited through a translocation signal that is poorly defined for conjugative relaxases. The relaxase TrwC of plasmid R388 is translocated by its cognate conjugative T4SS, and it can also be translocated by the VirB/D4 T4SS of Bartonella henselae, causing DNA transfer to human cells. In this work, we constructed a series of TrwC variants and assayed them for DNA transfer to bacteria and human cells to compare recruitment requirements by both T4SSs. Comparison with other reported relaxase translocation signals allowed us to determine two putative translocation sequence (TS) motifs, TS1 and TS2. Mutations affecting TS1 drastically affected conjugation frequencies, while mutations affecting either motif had only a mild effect on DNA transfer rates through the VirB/D4 T4SS of B. henselae. These results indicate that a single substrate can be recruited by two different T4SSs through different signals. The C terminus affected DNA transfer rates through both T4SSs tested, but no specific sequence requirement was detected. The addition of a Bartonella intracellular delivery (BID) domain, the translocation signal for the Bartonella VirB/D4 T4SS, increased DNA transfer up to 4% of infected human cells, providing an excellent tool for DNA delivery to specific cell types. We show that the R388 coupling protein TrwB is also required for this high-efficiency TrwC-BID translocation. Other elements apart from the coupling protein may also be involved in substrate recognition by T4SSs.

Alperi, Anabel; Larrea, Delfina; Fernandez-Gonzalez, Esther; Dehio, Christoph; Zechner, Ellen L.

2013-01-01

175

The hydrophilic translocator for Vibrio parahaemolyticus, T3SS2, is also translocated.  

PubMed

The pathogenesis of the diarrheal disease caused by Vibrio parahaemolyticus, a leading cause of seafood-associated enteritis worldwide, is dependent upon a type III secretion system, T3SS2. This apparatus enables the pathogen to inject bacterial proteins (effectors) into the cytosol of host cells and thereby modulate host processes. T3SS effector proteins transit into the host cell via a membrane pore (translocon) typically formed by 3 bacterial proteins. We have identified the third translocon protein for T3SS2: VopW, which was previously classified as an effector protein for a homologous T3SS in V. cholerae. VopW is a hydrophilic translocon protein; like other such proteins, it is not inserted into the host cell membrane but is required for insertion of the two hydrophobic translocators, VopB2 and VopD2, that constitute the membrane channel. VopW is not required for secretion of T3SS2 effectors into the bacterial culture medium; however, it is essential for transfer of these proteins into the host cell cytoplasm. Consequently, deletion of vopW abrogates the virulence of V. parahaemolyticus in several animal models of diarrheal disease. Unlike previously described hydrophilic translocators, VopW is itself translocated into the host cell cytoplasm, raising the possibility that it functions as both a translocator and an effector. PMID:22585964

Zhou, Xiaohui; Ritchie, Jennifer M; Hiyoshi, Hirotaka; Iida, Tetsuya; Davis, Brigid M; Waldor, Matthew K; Kodama, Toshio

2012-08-01

176

Translocation as a species conservation tool: Status and strategy  

USGS Publications Warehouse

Surveys of recent (1973 to 1986) intentional releases of native birds and mammals to the wild in Australia, Canada, Hawaii, New Zealand, and the United States, were conducted to document current activities, identify factors associated with success, and suggest guidelines for enhancing future work. Nearly 700 translocations were conducted each year. Native game species constituted percent of translocations and were more successful (86 percent) than were translocations of threatened, endangered, or sensitive species (46 percent). Knowledge of habitat quality, location of release area within the species range, number of animals released, program length, and reproductive traits, allowed currect classification of 81 percent of observed translocations as successful or not.

Griffith, B.; Scott, J.M.; Carpenter, J.W.; Reed, C.

1989-01-01

177

Direct Observation of Translocation in Individual DNA Polymerase Complexes*  

PubMed Central

Complexes of phi29 DNA polymerase and DNA fluctuate on the millisecond time scale between two ionic current amplitude states when captured atop the ?-hemolysin nanopore in an applied field. The lower amplitude state is stabilized by complementary dNTP and thus corresponds to complexes in the post-translocation state. We have demonstrated that in the upper amplitude state, the DNA is displaced by a distance of one nucleotide from the post-translocation state. We propose that the upper amplitude state corresponds to complexes in the pre-translocation state. Force exerted on the template strand biases the complexes toward the pre-translocation state. Based on the results of voltage and dNTP titrations, we concluded through mathematical modeling that complementary dNTP binds only to the post-translocation state, and we estimated the binding affinity. The equilibrium between the two states is influenced by active site-proximal DNA sequences. Consistent with the assignment of the upper amplitude state as the pre-translocation state, a DNA substrate that favors the pre-translocation state in complexes on the nanopore is a superior substrate in bulk phase for pyrophosphorolysis. There is also a correlation between DNA sequences that bias complexes toward the pre-translocation state and the rate of exonucleolysis in bulk phase, suggesting that during DNA synthesis the pathway for transfer of the primer strand from the polymerase to exonuclease active site initiates in the pre-translocation state.

Dahl, Joseph M.; Mai, Ai H.; Cherf, Gerald M.; Jetha, Nahid N.; Garalde, Daniel R.; Marziali, Andre; Akeson, Mark; Wang, Hongyun; Lieberman, Kate R.

2012-01-01

178

Three Translocations Involving C- or G-group Chromosomes  

PubMed Central

Three translocations each involving C or G chromosomes are reported. A familial translocation t(Cq+; Eq?) was identified to be rcp(6;18) (q2;q1) and two malformed children were then found to have a 46,XY(or XX),?6, +der(6) constitution. One of the carrier's pregnancy in this family was monitored by amniocentesis and a fetus was identified as being a male translocation carrier (balanced). Two other translocations were identified as rcp(11;14) (q12 or 13;q32?) and t(17;22) (p12 or 13?;q11?), respectively. Images

Nakagome, Yasuo; Iinuma, Kazuso; Matsui, Ichiro

1973-01-01

179

Chromosome translocations measured by fluorescence in-situ hybridization: A promising biomarker  

SciTech Connect

A biomarker for exposure and risk assessment would be most useful if it employs an endpoint that is highly quantitative, is stable with time, and is relevant to human risk. Recent advances in chromosome staining using fluorescence in situ hybridization (FISH) facilitate fast and reliable measurement of reciprocal translocations, a kind of DNA damage linked to both prior exposure and risk. In contrast to other biomarkers available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time post exposure, has a rather small inter-individual variability, and can be measured accurately at the low levels. Here, the authors discuss results from their studies demonstrating that chromosome painting can be used to reconstruct radiation dose for workers exposed within the dose limits, for individuals exposed a long time ago, and even for those who have been diagnosed with leukemia but not yet undergone therapy.

Lucas, J.N.; Straume, T.

1995-10-01

180

The protein translocation systems in plants - composition and variability on the example of Solanum lycopersicum  

PubMed Central

Background Protein translocation across membranes is a central process in all cells. In the past decades the molecular composition of the translocation systems in the membranes of the endoplasmic reticulum, peroxisomes, mitochondria and chloroplasts have been established based on the analysis of model organisms. Today, these results have to be transferred to other plant species. We bioinformatically determined the inventory of putative translocation factors in tomato (Solanum lycopersicum) by orthologue search and domain architecture analyses. In addition, we investigated the diversity of such systems by comparing our findings to the model organisms Saccharomyces cerevisiae, Arabidopsis thaliana and 12 other plant species. Results The literature search end up in a total of 130 translocation components in yeast and A. thaliana, which are either experimentally confirmed or homologous to experimentally confirmed factors. From our bioinformatic analysis (PGAP and OrthoMCL), we identified (co-)orthologues in plants, which in combination yielded 148 and 143 orthologues in A. thaliana and S. lycopersicum, respectively. Interestingly, we traced 82% overlap in findings from both approaches though we did not find any orthologues for 27% of the factors by either procedure. In turn, 29% of the factors displayed the presence of more than one (co-)orthologue in tomato. Moreover, our analysis revealed that the genomic composition of the translocation machineries in the bryophyte Physcomitrella patens resemble more to higher plants than to single celled green algae. The monocots (Z. mays and O. sativa) follow more or less a similar conservation pattern for encoding the translocon components. In contrast, a diverse pattern was observed in different eudicots. Conclusions The orthologue search shows in most cases a clear conservation of components of the translocation pathways/machineries. Only the Get-dependent integration of tail-anchored proteins seems to be distinct. Further, the complexity of the translocation pathway in terms of existing orthologues seems to vary among plant species. This might be the consequence of palaeoploidisation during evolution in plants; lineage specific whole genome duplications in Arabidopsis thaliana and triplications in Solanum lycopersicum.

2013-01-01

181

Background stratospheric aerosol layer  

SciTech Connect

Balloonborne aerosol particle counter measurements are used in studying the stratospheric sulfate layer at Laramie, Wyoming, during 1978 and 1979, a 2-year volcanically quiescent period in which the layer appears to have been in a near equilibrium background state. Subtracting the background aerosol concentration from data obtained during an earlier volcanically active period indicates that the actual decay rate of volcanic aerosol is over 30% faster than one would obtain without this correction. At background, the aerosol size distribution is found to remain remarkably constant between the tropopause and an altitude of approx.25 km, with a sudden transition to a distribution dominated by smaller particles above this altitude. The observations, in some respects, compare favorably with equilibrium one-dimensional stratospheric aerosol models and thus to some extent support the concept of relatively inert tropospheric sulfurous gases, such as carbonyl sulfide and carbon disulfide, as the main background stratospheric aerosol sulfur source. Models which incorporate sulfur chemistry are apparently not able to predict the observed variation of particle size with altitude. The 2-year background period is not long enough in itself to establish long-term trends. The eruption of Mt. St. Helens in May 1980 has considerably disrupted the background stratospheric aerosol which will probably not recover for several years. A comparison of the 1978--79 observations with Junge's original measurements made some 20 years earlier, also during a period void of volcanic perturbations, does not preclude a long-term increase in the background stratospheric aerosol level.

Hofmann, D.J.; Rosen, J.M.

1981-01-01

182

Association between simple sequence repeat-rich chromosome regions and intergenomic translocation breakpoints in natural populations of allopolyploid wild wheats  

PubMed Central

Background and Aims Repetitive DNA sequences are thought to be involved in the formation of chromosomal rearrangements. The aim of this study was to analyse the distribution of microsatellite clusters in Aegilops biuncialis and Aegilops geniculata, and its relationship with the intergenomic translocations in these allotetraploid species, wild genetic resources for wheat improvement. Methods The chromosomal localization of (ACG)n and (GAA)n microsatellite sequences in Ae. biuncialis and Ae. geniculata and in their diploid progenitors Aegilops comosa and Aegilops umbellulata was investigated by sequential in situ hybridization with simple sequence repeat (SSR) probes and repeated DNA probes (pSc119·2, Afa family and pTa71) and by dual-colour genomic in situ hybridization (GISH). Thirty-two Ae. biuncialis and 19 Ae. geniculata accessions were screened by GISH for intergenomic translocations, which were further characterized by fluorescence in situ hybridization and GISH. Key Results Single pericentromeric (ACG)n signals were localized on most U and on some M genome chromosomes, whereas strong pericentromeric and several intercalary and telomeric (GAA)n sites were observed on the Aegilops chromosomes. Three Ae. biuncialis accessions carried 7Ub–7Mb reciprocal translocations and one had a 7Ub–1Mb rearrangement, while two Ae. geniculata accessions carried 7Ug–1Mg or 5Ug–5Mg translocations. Conspicuous (ACG)n and/or (GAA)n clusters were located near the translocation breakpoints in eight of the ten translocated chromosomes analysed, SSR bands and breakpoints being statistically located at the same chromosomal site in six of them. Conclusions Intergenomic translocation breakpoints are frequently mapped to SSR-rich chromosomal regions in the allopolyploid species examined, suggesting that microsatellite repeated DNA sequences might facilitate the formation of those chromosomal rearrangements. The (ACG)n and (GAA)n SSR motifs serve as additional chromosome markers for the karyotypic analysis of UM genome Aegilops species.

Molnar, Istvan; Cifuentes, Marta; Schneider, Annamaria; Benavente, Elena; Molnar-Lang, Marta

2011-01-01

183

Melanotic Xp11 translocation renal cancer: report of a case with a unique intratumoral sarcoid-like reaction  

PubMed Central

Background Melanotic Xp11 translocation renal cancer is a rare tumor belonging to the family of microphthalmia-associated transcription factor (MiTF)/transcription factor E (TFE) neoplasms. This tumor family also includes alveolar soft part sarcoma, perivascular epithelioid cell neoplasms, Xp11 translocation renal cell carcinoma, and melanoma. To date, six confirmed melanotic Xp11 translocation cancers (five renal, one ovarian) have been reported in the literature. Case Report Here, we report the clinical, histologic, immunohistochemical, and molecular features of a unique melanotic Xp11 translocation renal cancer arising in a 34-year-old African-American female. Histologically, the tumor was composed of epithelioid tumor cells arranged in a nested pattern. The cells had clear to eosinophilic granular cytoplasm, vesicular nuclear chromatin, and prominent nucleoli. Multifocal intracytoplasmic deposits of granular brown melanin pigment were identified and confirmed by Fontana-Masson stain. An unusual histologic feature, not previously reported in melanotic Xp11 translocation renal cancer, was a sarcoid-like granulomatous reaction consisting of tight epithelioid granulomas with lymphocytic cuffing, numerous giant cells, and calcifications. Nuclear transcription factor E3 expression was identified by immunohistochemistry and TFE3 rearrangement was confirmed by fluorescence in situ hybridization. Additional immunohistochemical findings included immunoreactivity for HMB45, cathepsin K, and progesterone receptor; negative staining was seen with actin, desmin, cytokeratins, epithelial membrane antigen, CD10, vimentin, and PAX-8. The patient is currently free of disease, two years following initial clinicoradiologic presentation and twenty-two months following partial nephrectomy without additional therapy. Conclusion This report further expands the spectrum of morphologic and clinical findings previously described in melanotic Xp11 translocation renal cancer, a distinctive tumor showing overlapping features between Xp11 translocation renal cell carcinoma, melanoma, and perivascular epithelioid cell neoplasms. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7225796341180634

2014-01-01

184

The cosmic neutrino background  

NASA Technical Reports Server (NTRS)

The cosmic neutrino background is expected to consist of relic neutrinos from the big bang, of neutrinos produced during nuclear burning in stars, of neutrinos released by gravitational stellar collapse, and of neutrinos produced by cosmic ray interactions with matter and radiation in the interstellar and intergalactic medium. Formation of baryonic dark matter in the early universe, matter-antimatter annihilation in a baryonic symmetric universe, and dark matter annihilation could have also contributed significantly to the cosmic neutrino background. The purpose of this paper is to review the properties of these cosmic neutrino backgrounds, the indirect evidence for their existence, and the prospects for their detection.

Dar, Arnon

1991-01-01

185

Over half of breakpoints in gene pairs involved in cancer-specific recurrent translocations are mapped to human chromosomal fragile sites  

PubMed Central

Background Gene rearrangements such as chromosomal translocations have been shown to contribute to cancer development. Human chromosomal fragile sites are regions of the genome especially prone to breakage, and have been implicated in various chromosome abnormalities found in cancer. However, there has been no comprehensive and quantitative examination of the location of fragile sites in relation to all chromosomal aberrations. Results Using up-to-date databases containing all cancer-specific recurrent translocations, we have examined 444 unique pairs of genes involved in these translocations to determine the correlation of translocation breakpoints and fragile sites in the gene pairs. We found that over half (52%) of translocation breakpoints in at least one gene of these gene pairs are mapped to fragile sites. Among these, we examined the DNA sequences within and flanking three randomly selected pairs of translocation-prone genes, and found that they exhibit characteristic features of fragile DNA, with frequent AT-rich flexibility islands and the potential of forming highly stable secondary structures. Conclusion Our study is the first to examine gene pairs involved in all recurrent chromosomal translocations observed in tumor cells, and to correlate the location of more than half of breakpoints to positions of known fragile sites. These results provide strong evidence to support a causative role for fragile sites in the generation of cancer-specific chromosomal rearrangements.

Burrow, Allison A; Williams, Laura E; Pierce, Levi CT; Wang, Yuh-Hwa

2009-01-01

186

Multistep protein unfolding during nanopore translocation  

NASA Astrophysics Data System (ADS)

Cells are divided into compartments and separated from the environment by lipid bilayer membranes. Essential molecules are transported back and forth across the membranes. We have investigated how folded proteins use narrow transmembrane pores to move between compartments. During this process, the proteins must unfold. To examine co-translocational unfolding of individual molecules, we tagged protein substrates with oligonucleotides to enable potential-driven unidirectional movement through a model protein nanopore, a process that differs fundamentally from extension during force spectroscopy measurements. Our findings support a four-step translocation mechanism for model thioredoxin substrates. First, the DNA tag is captured by the pore. Second, the oligonucleotide is pulled through the pore, causing local unfolding of the C terminus of the thioredoxin adjacent to the pore entrance. Third, the remainder of the protein unfolds spontaneously. Finally, the unfolded polypeptide diffuses through the pore into the recipient compartment. The unfolding pathway elucidated here differs from those revealed by denaturation experiments in solution, for which two-state mechanisms have been proposed.

Rodriguez-Larrea, David; Bayley, Hagan

2013-04-01

187

Cryptopleurine--an inhibitor of translocation.  

PubMed

Ribosomes from a cryptopleurine-resistant mutant of yeast were analyzed to determine the subunit localization of the resistance alteration. As was previously reported (Grant, P., Sanchez, L., and Jiminez, A. (1974), J. Bacteriol. 120, 1308), in vitro resistance of polyphenylalanine synthesis to cryptopleurine was conferred by 40S subunits from the mutant. Binding studies with sensitive ribosomes were carried out in order to identify the subunit binding site for cryptopleurine. Over the range of concentrations which inhibited polyphenylalanine synthesis, binding was proportional to concentration, so that a unique binding site could not be detected. Furthermore, binding to isolated subunits was about fourfold greater than to 80S ribosomes, suggesting that non-specific binding was sensitive to the condition of the particles. Model systems were developed in order to determine which step of the elongation cycle was inhibited by cryptopleurine. Elongation factor 1 dependent binding of Phe-tRNA to ribosomes was not inhibited by cryptopleurine concentrations, which inhibited polyphenylalanine synthesis. The initial rate of N-acetylphenylalanylpuromycin formation was inhibited when 10(-5) M cryptopleurine was added prior to translocation, but not when added after. Little inhibition was observed in either case when mutant ribosomes were used. These results suggest that cryptopleurine primarily inhibited translocation. PMID:791357

Bucher, K; Skogerson, L

1976-11-01

188

The archaeal twin-arginine translocation pathway.  

PubMed

The twin-arginine translocation (Tat) pathway is a system with the unique ability to export proteins in a fully folded conformation. Its main components are TatA, TatB and TatC, all of which are required for Tat-dependent export. The Tat pathway is found in several Archaea, and in most of them a moderate number of predicted Tat-dependent substrates are present. Putative substrates include those binding cofactors such as iron-sulphur clusters and molybdopterin. In these Archaea, the role of the Tat pathway seems to be similar to that of bacteria: the export of a small subset of proteins that fold before translocation across the cytoplasmic membrane. The exception to this is the Tat system of the halophilic archaeon Halobacterium sp. NRC-1. In this organism, the majority of extra-cytoplasmic proteins are predicted to use the Tat pathway, which is, most likely, a specific adaptation to its particular lifestyle in highly saline conditions. PMID:12773183

Hutcheon, G W; Bolhuis, A

2003-06-01

189

Evolutionary Effects of Translocations in Bacterial Genomes  

PubMed Central

It has become clear that different genome regions need not evolve uniformly. This variation is particularly evident in bacterial genomes with multiple chromosomes, in which smaller, secondary chromosomes evolve more rapidly. We previously demonstrated that substitution rates and gene dispensability were greater on secondary chromosomes in many bacterial genomes. In Vibrio, the secondary chromosome is replicated later during the cell cycle, which reduces the effective dosage of these genes and hence their expression. More rapid evolution of secondary chromosomes may therefore reflect weaker purifying selection on less expressed genes. Here, we test this hypothesis by relating substitution rates of orthologs shared by multiple Burkholderia genomes, each with three chromosomes, to a study of gene expression in genomes differing by a major reciprocal translocation. This model predicts that expression should be greatest on chromosome 1 (the largest) and least on chromosome 3 (the smallest) and that expression should tend to decline within chromosomes from replication origin to terminus. Moreover, gene movement to the primary chromosome should associate with increased expression, and movement to secondary chromosomes should result in reduced expression. Our analysis supports each of these predictions, as translocated genes tended to shift expression toward their new chromosome neighbors despite inevitable cis-acting regulation of expression. This study sheds light on the early dynamics of genomes following rearrangement and illustrates how secondary chromosomes in bacteria may become evolutionary test beds.

Cooper, Vaughn S.

2012-01-01

190

Extremely low frequency magnetic fields in residences in Germany. Distribution of measurements, comparison of two methods for assessing exposure, and predictors for the occurrence of magnetic fields above background level.  

PubMed

We examined the results of 1,835 magnetic field measurements in German residences conducted between November 1997 and September 1999. The measurements were part of an epidemiological study on the relationship between magnetic fields and childhood leukemia. We performed a fixed-location measurement of the magnetic field at 50 Hz and 16 2/3 Hz (frequency of the German railway system) over 24 h in the child's bedroom in the residence of each study participant. In addition, we conducted a second 24 h-measurement in the living room at 50 Hz, and spot measurements while walking through all rooms of the respective dwelling. Median 50 Hz magnetic fields above 0.2 muT were found to be infrequent in Germany (only 1.4% of all residences). Fields produced by high-voltage power lines (123-420 kV) were lower than expected: the median magnetic field was above 0.2 muT in only 8 (32.0%) of 25 residences located 50 m or closer to a high-voltage power line indicating that power lines in Germany are usually run well below the maximum power load. We found that magnetic fields were correlated with the type of residence and higher magnetic fields were measured in apartment buildings. There was also some evidence for a positive correlation between magnetic fields and traffic density and an inverse association between magnetic fields and family net income. The 24 h-magnetic field measurements correlated well with the spot measurements (r>0.7). However, when dichotomized with a cut-off point of 0.2 muT, there was only a poor agreement between the two measurement methods. A loss of the strength of the association after categorization was also observed when comparing the arithmetic mean and median of the same 24 h-measurement. In summary, these analyses give a valuable overview of magnetic field distributions in German residences. PMID:11200967

Schüz, J; Grigat, J P; Störmer, B; Rippin, G; Brinkmann, K; Michaelis, J

2000-12-01

191

Building Background Knowledge  

NSDL National Science Digital Library

Too often, students enter our classrooms with insufficient knowledge of physical science. As a result, they have a difficult time understanding content in texts, lectures, and laboratory activities. This lack of background knowledge can have an impact on

Ross, Donna; Fisher, Douglas; Grant, Maria

2010-01-01

192

Background and Statistics  

MedlinePLUS

Background & Statistics FAQ About Homeless Veterans Homeless Veterans Facts Demographics of Homeless Veterans Incarcerated Veterans Research Briefs Sources FAQ ... VETERANS In May 2007, the Bureau of Justice Statistics released a special report on incarcerated veterans. The ...

193

Background Oriented Schlieren Demonstrations.  

National Technical Information Service (NTIS)

In this project report we present the application of a novel schlieren technique for two different tests. The optical method is referred to as 'Background Oriented Schlieren' (BOS) in the following. Additionally the differences between BOS and an extensio...

H. Richard M. Raffel

2000-01-01

194

Relativistic plasma in a homogeneous cosmological background  

NASA Astrophysics Data System (ADS)

The linearized theory of a relativistic plasma in a radiation background, proposed recently by Holcomb and Tajima, is extended for a more general background with the metric components being an arbitrary power function of time (~tn). It is noted that the electric field falls off faster and the redshift of the electromagnetic radiation frequency is also greater in a more rapidly expanding background universe. The dispersion relation for the transverse vibration of the electromagnetic field, however, appears to be independent of the parameter n. The wave equation for the electric field is solved for a de Sitter background also.

Banerjee, A.; Chatterjee, S.; Sil, A.; Banerjee, N.

1994-07-01

195

Cadmium uptake and translocation in seedlings of near isogenic lines of durum wheat that differ in grain cadmium accumulation  

PubMed Central

Background Cadmium (Cd) concentrations in durum wheat (Triticum turgidum L. var durum) grain grown in North American prairie soils often exceed proposed international trade standards. To understand the physiological processes responsible for elevated Cd accumulation in shoots and grain, Cd uptake and translocation were studied in seedlings of a pair of near-isogenic durum wheat lines, high and low for Cd accumulation in grain. Results In short-term studies (<3 h) using 109Cd-labelled nutrient solutions, there were no differences between lines in time- or concentration-dependent 109Cd accumulation by roots. In contrast, rates of 109Cd translocation from roots to shoots following longer exposure (48–60 h) were 1.8-fold higher in the high Cd-accumulating line, despite equal whole-plant 109Cd accumulation in the lines. Over the same period, the 109Cd concentration in root-pressure xylem exudates was 1.7 to 1.9-fold higher in the high Cd-accumulating line. There were no differences between the lines in 65Zn accumulation or partitioning that could account for the difference between lines in 109Cd translocation. Conclusion These results suggest that restricted root-to-shoot Cd translocation may limit Cd accumulation in durum wheat grain by directly controlling Cd translocation from roots during grain filling, or by controlling the size of shoot Cd pools that can be remobilised to the grain.

Harris, Neil S; Taylor, Gregory J

2004-01-01

196

Allopurinol and glutamine attenuate bacterial translocation in chronic portal hypertensive and common bile duct ligated growing rats.  

PubMed Central

BACKGROUND: Spontaneous bacterial infections and septicaemia result in morbidity and mortality in patients with portal hypertension and obstructive jaundice. AIM: The aim of this study in rats was to investigate the incidence of bacterial translocation in portal hypertension and obstructive jaundice, and to evaluate the effects of allopurinol and glutamine. METHODS: Rats were subjected to sham laparotomy (SL), portal hypertension (PH) by calibrated stenosis of the portal vein, and common bile duct ligation (CBDL). Animals of each group were either treated with allopurinol (50 mg/kg twice a week), glutamine (1 g/kg/d), and allopurinol and glutamine. RESULTS: After four weeks, significant bacterial translocation in the untreated PH and CBDL rats occurred. Intestinal mucosal malondialdehyde concentrations (MDA), as an indicator for lipid peroxidation, and myeloperoxidase activity (MPO) released from activated neutrophils were also significantly increased (p < 0.01). Allopurinol and glutamine in PH and CBDL rats improved bacterial translocation, and decreased MDA and MPO values (p < 0.01). CONCLUSION: In PH and CBDL rats significant bacterial translocation, ileal mucosal lipid peroxidation, and neutrophil derived MPO activity occurred. Allopurinol and glutamine significantly reduced bacterial translocation, as well as ileal mucosal MDA and MPO activities. Images Figure 3 Figure 4

Schimpl, G; Pesendorfer, P; Steinwender, G; Feierl, G; Ratschek, M; Hollwarth, M E

1996-01-01

197

Translocation and fidelity of Escherichia coli RNA polymerase  

PubMed Central

Exonuclease (exo) III was used as a probe of the Escherichia coli RNA polymerase (RNAP) ternary elongation complex (TEC) downstream border. In the absence of NTPs, RNAP appears to stall primarily in a post-translocated state and to return slowly to a pre-translocated state. Exo III mapping, therefore, appears inconsistent with an unrestrained thermal ratchet model for translocation, in which RNAP freely and rapidly oscillates between pre- and post-translocated positions. The forward translocation state is made more stable by lowering the pH and/or by elevating the salt concentration, indicating a probable role of protonated histidine(s) in regulating accurate NTP loading and translocation. Because the post-translocated TEC can be strongly stabilized by NTP addition, NTP analogs were ranked for their ability to preserve the post-translocation state, giving insight into RNAP fidelity. Effects of NTPs (and analogs) and analysis of chemically modified RNA 3? ends demonstrate that patterns of exo III mapping arise from intrinsic and subtle alterations at the RNAP active site, far from the site of exo III action.

Nedialkov, Yuri A.; Burton, Zachary F.

2013-01-01

198

Adsorption-driven translocation of polymer chain into nanopores  

NASA Astrophysics Data System (ADS)

The polymer translocation into nanopores is generally facilitated by external driving forces, such as electric or hydrodynamic fields, to compensate for entropic restrictions imposed by the confinement. We investigate the dynamics of translocation driven by polymer adsorption to the confining walls that is relevant to chromatographic separation of macromolecules. By using the self-consistent field theory, we study the passage of a chain trough a small opening from cis to trans compartments of spherical shape with adsorption potential applied in the trans compartment. The chain transfer is modeled as the Fokker-Plank diffusion along the free energy landscape of the translocation pass represented as a sum of the free energies of cis and trans parts of the chain tethered to the pore opening. We investigate how the chain length, the size of trans compartment, the magnitude of adsorption potential, and the extent of excluded volume interactions affect the translocation time and its distribution. Interplay of these factors brings about a variety of different translocation regimes. We show that excluded volume interactions within a certain range of adsorption potentials can cause a local minimum on the free energy landscape, which is absent for ideal chains. The adsorption potential always leads to the decrease of the free energy barrier, increasing the probability of successful translocation. However, the translocation time depends non-monotonically of the magnitude of adsorption potential. Our calculations predict the existence of the critical magnitude of adsorption potential, which separates favorable and unfavorable regimes of translocation.

Yang, Shuang; Neimark, Alexander V.

2012-06-01

199

Studies of DNA Translocation Dynamics Using Asymmetrical Nanopores  

NASA Astrophysics Data System (ADS)

Despite extensive studies of DNA translocations through voltage-biased solid-state nanopores, the influence of the DNA coil on the translocation dynamics remains poorly understood. We investigated this issue experimentally by controlling the separation between the DNA coil and the nanopore. We studied lambda DNA translocations through devices comprising a 400 nm-high, 2500 nm-wide, disc-shaped cavity bounded from above by a 20 nm-thin silicon nitride membrane with a 10 nm wide nanopore in the center, and from below by at 400 nm-thick silicon nitride membrane with a 300 nm-wide opening in the center. The asymmetric nanopore-cavity structure introduced an 800 nm gap between the initial DNA coil and the nanopore when a molecule translocated from below, but no gap when it translocated from above. Translocation times were longer and the integrated charge deficit was larger for molecules translocating from below. These results are explained by the viscous drag on the DNA outside the pore, whose importance relative to the drag inside the pore we quantify. We outline a consistent model of DNA translocation speeds that depends on the initial configuration of the DNA coil, similar to the velocity fluctuation model of Lu et al.

Liu, Xu; Dipetrillo, Karri; Chan, Jason; Stein, Derek

2012-02-01

200

Gene-tagged chromosome translocations in eleven stocks of mice  

Microsoft Academic Search

Summary  The cytogenetic problems of correlating linkage groups in the house mouse with their chromosomes, and of establishing the\\u000a chromosomal independence of known linkage groups, call for the use of numerous genetically tagged translocations. Eleven new\\u000a translocations have been induced and tagged; they involve linkage groups I, II, III, V, VIII, IX and XI.

T. G. Cartes; Mary F. Lyon; Rita J. S. Phillips

1955-01-01

201

Chromosomal Translocation and Segmental Duplication in Cryptococcus neoformans  

Microsoft Academic Search

Large chromosomal events such as translocations and segmental duplications enable rapid adaptation to new environments. Here we marshal genomic, genetic, meiotic mapping, and physical evidence to demonstrate that a chromosomal translocation and segmental duplication occurred during construction of a congenic strain pair in the fungal human pathogen Cryptococcus neoformans. Two chromosomes underwent telomere-telomere fusion, generating a dicentric chromosome that broke

James A. Fraser; Johnny C. Huang; Read Pukkila-Worley; J. Andrew Alspaugh; Thomas G. Mitchell; Joseph Heitman

2005-01-01

202

Molecular dynamics study on DNA oligonucleotide translocation through carbon nanotubes  

Microsoft Academic Search

Molecular dynamics simulations are performed to study the translocation of a DNA oligonucleotide in a carbon nanotube (CNT) channel consisting of CNTs of two different diameters. A strong gravitational acceleration field is applied to the DNA molecule and water solvent as an external driving force for the translocation. It is observed that both the CNT channel size and the strength

Q. X. Pei; C. G. Lim; Y. Cheng; Huajian Gao

2008-01-01

203

Unitarity and singular backgrounds  

NASA Astrophysics Data System (ADS)

We compute the graviton Kaluza-Klein spectrum on a gravity-dilaton background with a naked singularity for all possible boundary conditions at the singularity which are consistent with unitary evolution. We apply methods from nonrelativistic quantum mechanics with singular Schrödinger potentials. In general, the spectrum contains a tachyon, a sign of instability. Only for a particular boundary condition at the singularity is the spectrum free of tachyons. In this case, the lowest-lying graviton mode is massless. We argue that this result will also hold for other backgrounds with similar geometry near the curvature singularity. We complete our study with a brief discussion on radion perturbations and the Higgs mechanism on this singular background.

Brouzakis, Nikolaos; Quiros, Mariano

2013-11-01

204

Range-wide success of red-cockaded woodpecker translocations.  

SciTech Connect

Edwards, John W.; Costa, Ralph. 2004. Range-wide success of red-cockaded woodpecker translocations. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 6. Translocation. Pp 307-311. Abstract: Red-cockaded woodpeckers (Picoides borealis) have declined range-wide during the past century, suffering from habitat loss and the effects of fire exclusion in older southern pine forests. Red-cockaded woodpecker translocations are a potentially important tool in conservation efforts to reestablish red-cockaded woodpeckers in areas from which they have been extirpated. Currently, translocations are critical in ongoing efforts to save and restore the many existing small populations. We examined the effects of demographic and environmental factors on the range-wide success of translocations between 1989 and 1995.

Edwards, John W.; Costa, Ralph

2004-12-31

205

Strandwise translocation of a DNA glycosylase on undamaged DNA  

SciTech Connect

Base excision repair of genotoxic nucleobase lesions in the genome is critically dependent upon the ability of DNA glycosylases to locate rare sites of damage embedded in a vast excess of undamaged DNA, using only thermal energy to fuel the search process. Considerable interest surrounds the question of how DNA glycosylases translocate efficiently along DNA while maintaining their vigilance for target damaged sites. Here, we report the observation of strandwise translocation of 8-oxoguanine DNA glycosylase, MutM, along undamaged DNA. In these complexes, the protein is observed to translocate by one nucleotide on one strand while remaining untranslocated on the complementary strand. We further report that alterations of single base-pairs or a single amino acid substitution (R112A) can induce strandwise translocation. Molecular dynamics simulations confirm that MutM can translocate along DNA in a strandwise fashion. These observations reveal a previously unobserved mode of movement for a DNA-binding protein along the surface of DNA.

Qi, Yan; Nam, Kwangho; Spong, Marie C.; Banerjee, Anirban; Sung, Rou-Jia; Zhang, Michael; Karplus, Martin; Verdine, Gregory L. (Harvard)

2012-05-14

206

The Cosmic Background Explorer  

NASA Technical Reports Server (NTRS)

The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

1990-01-01

207

Cosmic Microwave Background  

NSDL National Science Digital Library

In this lesson, students explore the cosmic microwave background to understand why it permeates the universe and why it peaks as microwave radiation. Students should be able to explain that the origin of the background radiation is the uniform thermal radiation of the big bang and that the radiation produced was evenly distributed around the small early universe, causing it to permeate today's universe. This activity is part of the Cosmic Times teachers guide and is intended to be used in conjunction with the 1965 Cosmic Times Poster.

208

Micro-Evolution in Grasshoppers Mediated by Polymorphic Robertsonian Translocations  

PubMed Central

This review focuses on grasshoppers that are polymorphic for Robertsonian translocations because in these organisms the clarity of meiotic figures allows the study of both chiasma distribution and the orientation of trivalents and multivalents in metaphase I. Only five species of such grasshoppers were found in the literature, and all of them were from the New World: Oedaleonotus enigma (Scudder) (Orthoptera: Acrididae), Leptysma argentina Bruner, Dichroplus pratensis Bruner, Sinipta dalmani Stål, and Cornops aquaticum Bruner. A general feature of these species (except O. enigma) is that fusion carriers suffer a marked reduction of proximal and interstitial (with respect to the centromere) chiasma frequency; this fact, along with the reduction in the number of linkage groups with the consequent loss of independent segregation, produces a marked decrease of recombination in fusion carriers. This reduction in recombination has led to the conclusion that Robertsonian polymorphic grasshopper species share some properties with inversion polymorphic species of Drosophila, such as the central-marginal pattern (marginal populations are monomorphic, central populations are highly polymorphic). This pattern might be present in D. pratensis, which is certainly the most complex Robertsonian polymorphism system in the present study. However, L. argentina and C. aquaticum do not display this pattern. This issue is open to further research. Since C. aquaticum is soon to be released in South Africa as a biological control, the latitudinal pattern found in South America may repeat there. This experiment's outcome is open and deserves to be followed.

Colombo, Pablo C.

2013-01-01

209

Adaptive control is enhanced by background estimation  

Microsoft Academic Search

To allow for simultaneous real-time identification of background as well as the parameters of an autoregressive moving average model with exogenous inputs (ARMAX model) during adaptive control, a floating identifier (FI) approach is developed which may be used with most recursive identification algorithms. This method separates input and output data into low- and high-frequency components. The high-frequency components are used

William Donald Timmons; Howard J. Chizeck; Peter G. Katona

1991-01-01

210

Fetal irradiation of rats induces persistent translocations in mammary epithelial cells similar to the level after adult irradiation, but not in hematolymphoid cells.  

PubMed

In both humans and mice, fetal exposure to radiation fails to induce a persistent increase in the frequency of chromosome aberrations in blood lymphocytes. Such a low-level response to radiation exposure is counterintuitive in view of the generally accepted belief that a fetus is sensitive to radiation. To determine if this is a general phenomenon, both mammary epithelial cells and spleen cells were studied in rats. Fetuses of 17.5 days postcoitus were irradiated with 2 Gy of gamma rays, and mammary tissues were removed 6-45 weeks later. Subsequently, short-term cultures were established to detect translocations using the two-color FISH method. The results showed that translocation frequencies were not only elevated in rats irradiated as fetuses, but were also almost as high as those in rats that were irradiated as adults (12 weeks old, pregnant mothers or young virgins) and examined 6-45 weeks later. There was no evidence of higher sensitivity in fetal cells with respect to the induction of translocations. In contrast, translocation frequencies in spleen cells were not elevated in adult rats irradiated as fetuses but were increased after irradiation of adults as previously seen in mouse spleen cells and human T lymphocytes. In the case of irradiation of adult rats, the induced translocation frequencies were similar between spleen cells and mammary epithelial cells. If we take translocation frequency as a surrogate marker of potential carcinogenic effect of radiation, the current results suggest that fetal irradiation can induce persistent potential carcinogenic damage in mammary stem/progenitor cells but this does not contribute to the increased risk of cancer since it has been reported that irradiation of fetal rats of the SD strain does not increase the risk of mammary cancers. Possible reasons for this discrepancy are discussed. PMID:24512615

Nakano, Mimako; Nishimura, Mayumi; Hamasaki, Kanya; Mishima, Shuji; Yoshida, Mitsuaki; Nakata, Akifumi; Shimada, Yoshiya; Noda, Asao; Nakamura, Nori; Kodama, Yoshiaki

2014-02-01

211

Targets, backgrounds, and discrimination  

Microsoft Academic Search

The present volume discusses a model-based aircraft identification technique, target intensity and angle scintillations, spatiotemporal nonstationary scene generation, an overview of the Strategic Scene Generation Model (SSGM), nuclear backgrounds for SSGM, and an atmospheric and transmittance code for 50-300 km altitudes. Also discussed are a data base for airborne target signatures, the auroral module of the Strategic High Altitude Radiance

J. S. Accetta; G. H. Kelley

1992-01-01

212

The Cosmic Background Radiation  

Microsoft Academic Search

We review the current status of experimental data for spectral distortions and angular anisotropies of the cosmic microwave background, as well as discussing the relevant physical processes. This is one of a number of new articles in astrophysics and cosmology which will appear in the 1996 Review of Particle Properties (Phys. Rev. D. in press). Other relevant reviews include: \\

G. F. Smoot; D. Scott

1996-01-01

213

The other backgrounds  

Microsoft Academic Search

The significance of the cosmic microwave background or CMB (3K, ther- mal, relict, black body, isotropic, etc) radiation in confirming a hot big bang model of the early Universe and in setting precise values of many of the parameters of that model is widely known and has recently been enhanced by the results of three years of operation of the

Virginia Trimble

2006-01-01

214

Iran: The Background.  

National Technical Information Service (NTIS)

The set is composed of three reports which are also available individually from NTIS. The set was assembled to provide scholars and other interested persons with historical background to the U.S.-Iran crisis of 1979-80. ;Titles included in the set are: IR...

1979-01-01

215

Translocation as a tool for mitigating conflict with leopards in human-dominated landscapes of India.  

PubMed

We examined the efficacy of a translocation program in which large numbers of leopards (Panthera pardus fusca) were trapped in human-dominated landscapes where livestock attacks were common and human attacks rare and released into adjoining forested areas in an attempt to reduce leopard presence and mitigate conflicts at the capture site. In the year starting in February of 2001, 29 leopards were captured in the human-dominated rural landscape of the Junnar region (4275 km(2) , 185 people/km(2) ), Maharashtra, India, and released an average of 39.5 km away in adjoining forests. Eleven leopards were also relocated to the same forests from other districts. Prior to the large-scale translocation program, an average of four leopard attacks on humans occurred each year between 1993 and 2001. After the translocation program was initiated, the average increased substantially to 17 attacks. Linear and logistic models showed that attack frequency increased in Junnar following nearby releases of leopards and decreased when leopards were removed for releases far away; that attacks became more lethal when the number of leopards introduced from other districts increased; and that attacks were most likely to occur in the regions where the largest number of leopards had been introduced from other areas. These results suggest that leopards did not stay at the release sites and that translocation induced attacks on people. Potential explanations for these results include increased aggression induced by stress of the translocation process, movement through unfamiliar human-dominated landscapes following release, and loss of fear of humans due to familiarity with humans acquired during captivity. Our results show that reactive solutions to attacks on humans by leopards, such as translocation, could in fact increase human-leopard conflict. Measures to reduce human-carnivore conflicts may include more effective compensation procedures to pay livestock owners for the loss of animals to predation by carnivores, providing better methods of protection for livestock, and encouraging greater social acceptance of the presence of carnivores in human-dominated landscapes. PMID:21054526

Athreya, Vidya; Odden, Morten; Linnell, John D C; Karanth, K Ullas

2011-02-01

216

Defective double-strand DNA break repair and chromosomal translocations by MYC overexpression.  

PubMed

DNA repair mechanisms are essential for the maintenance of genomic integrity. Disruption of gene products responsible for DNA repair can result in chromosomal damage. Improperly repaired chromosomal damage can result in the loss of chromosomes or the generation of chromosomal deletions or translocations, which can lead to tumorigenesis. The MYC protooncogene is a transcription factor whose overexpression is frequently associated with human neoplasia. MYC has not been previously implicated in a role in DNA repair. Here we report that the overexpression of MYC disrupts the repair of double-strand DNA breaks, resulting in a several-magnitude increase in chromosomal breaks and translocations. We found that MYC inhibited the repair of gamma irradiation DNA breaks in normal human cells and blocked the repair of a single double-strand break engineered to occur in an immortal cell line. By spectral karyotypic analysis, we found that MYC even within one cell division cycle resulted in a several-magnitude increase in the frequency of chromosomal breaks and translocations in normal human cells. Hence, MYC overexpression may be a previously undescribed example of a dominant mutator that may fuel tumorigenesis by inducing chromosomal damage. PMID:12909717

Karlsson, Asa; Deb-Basu, Debabrita; Cherry, Athena; Turner, Stephanie; Ford, James; Felsher, Dean W

2003-08-19

217

Dialysis dose and frequency  

Microsoft Academic Search

Background. From the beginning of the dialysis era, the issue of optimal dialysis dose and frequency has been a central topic in the delivery of dialysis treatment. Methods. We undertook a discussion to achieve a consensus on key points relating to dialysis dose and frequency, focusing on the relationships with clinical and patient outcomes. Results. Traditionally, dialysis adequacy has been

Francesco Locatelli; Umberto Buoncristiani; Bernard Canaud; Hans Kohler; Thierry Petitclerc; Pietro Zucchelli; Ospedale A. Manzoni; CHU Montpellier; Schwerpunkt Nephrologie

2004-01-01

218

Crystal structure of the Yersinia enterocolitica type III secretion chaperone SycD in complex with a peptide of the minor translocator YopD  

PubMed Central

Background Type III secretion systems are used by Gram-negative bacteria as “macromolecular syringes” to inject effector proteins into eukaryotic cells. Two hydrophobic proteins called translocators form the necessary pore in the host cell membrane. Both translocators depend on binding to a single chaperone in the bacterial cytoplasm to ensure their stability and efficient transport through the secretion needle. It was suggested that the conserved chaperones bind the more divergent translocators via a hexapeptide motif that is found in both translocators and conserved between species. Results We crystallized a synthetic decapeptide from the Yersinia enterocolitica minor type III secretion translocator YopD bound to its cognate chaperone SycD and determined the complex structure at 2.5?Å resolution. The structure of peptide-bound SycD is almost identical to that of apo SycD with an all helical fold consisting of three tetratricopeptide repeats (TPRs) and an additional C-terminal helix. Peptide-bound SycD formed a kinked head-to-head dimer that had previously been observed for the apo form of SycD. The homodimer interface comprises both helices of the first tetratricopeptide repeat. The YopD peptide bound in extended conformation into a mainly hydrophobic groove on the concave side of SycD. TPRs 1 and 2 of SycD form three hydrophobic pockets that accommodated the conserved hydrophobic residues at position 1, 3 and 6 of the translocator hexapeptide sequence. Two tyrosines that are highly conserved among translocator chaperones contribute to the hydrophobic patches but also form hydrogen bonds to the peptide backbone. Conclusions The interaction between SycD and YopD is very similar to the binding of the Pseudomonas minor translocator PopD to its chaperone PcrH and the Shigella major translocator IpaB to its chaperone IpgC. This confirms the prediction made by Kolbe and co-workers that a hexapeptide with hydrophobic residues at three positions is a conserved chaperone binding motif. Because the hydrophobic groove on the concave side of translocator chaperones is involved in binding of the major and the minor translocator, simultaneous binding of both translocators to a single type III secretion class II chaperone appears unlikely.

2012-01-01

219

Chromosome Segregation Analysis in Human Embryos Obtained from Couples Involving Male Carriers of Reciprocal or Robertsonian Translocation  

PubMed Central

The objective of this study was to investigate the frequency and type of chromosome segregation patterns in cleavage stage embryos obtained from male carriers of Robertsonian (ROB) and reciprocal (REC) translocations undergoing preimplantation genetic diagnosis (PGD) at our reproductive center. We used FISH to analyze chromosome segregation in 308 day 3 cleavage stage embryos obtained from 26 patients. The percentage of embryos consistent with normal or balanced segregation (55.1% vs. 27.1%) and clinical pregnancy (62.5% vs. 19.2%) rates were higher in ROB than the REC translocation carriers. Involvement of non-acrocentric chromosome(s) or terminal breakpoint(s) in reciprocal translocations was associated with an increase in the percent of embryos consistent with adjacent 1 but with a decrease in 3?1 segregation. Similar results were obtained in the analysis of nontransferred embryos donated for research. 3?1 segregation was the most frequent segregation type in both day 3 (31%) and spare (35%) embryos obtained from carriers of t(11;22)(q23;q11), the only non-random REC with the same breakpoint reported in a large number of unrelated families mainly identified by the birth of a child with derivative chromosome 22. These results suggest that chromosome segregation patterns in day 3 and nontransferred embryos obtained from male translocation carriers vary with the type of translocation and involvement of acrocentric chromosome(s) or terminal breakpoint(s). These results should be helpful in estimating reproductive success in translocation carriers undergoing PGD.

Chung, Jin-Tae; Tan, Seang Lin; Holzer, Hananel; Ao, Asangla

2012-01-01

220

Diffuse UV Background Radiation  

NASA Astrophysics Data System (ADS)

The diffuse UV sky is expected to glow with significant amounts of starlight that is scattered from the interstellar dust. The albedo and scattering pattern of the dust in the ultraviolet are both well established, and are both fairly independent of wavelength from 912 Å to 3000 Å. We present 1943 Voyager spectra of the diffuse cosmic background radiation from 500 Å to 1200 Å, and we compare their brightnesses, and their distribution on the sky, to those observed (Murthy et al., ApJ 724, 1389, 2010) from the GALEX mission at longer wavelengths (1530 Å). Significant differences appear, suggesting that background radiation components in addition to dust-scattered starlight may be present in both spectral regions.

Conn Henry, Richard; Murthy, J.

2012-01-01

221

Background illumination simulator  

SciTech Connect

This patent describes a testing apparatus for testing and evaluating the performance of laser seeking warheads for missiles, under simulated weather conditions. It comprises support means for supporting a warhead seeker; laser means for generating a laser beam and for directing a laser beam towards the seeker; a diffusion screen interposed between the seeker support means and the laser means for diffusing the laser beam; a collimating lens interposed between the diffusion screen and the seeker support means for collimating the diffused laser beam and for directing the collimated laser beam onto a warhead seeker, supported in the seeker support; background illuminator means for illuminating the seeker support and a seeker disposed therein, supported for movement into and out of an operating position between the diffusion means and the collimating lens for providing background lighting in simulation of weather lighting conditions; and control means for controlling the intensity of the light provided by the illuminator means to simulate various weather conditions.

Towry, E.R.

1992-05-12

222

Executive summary: Background  

NASA Technical Reports Server (NTRS)

Background information on, and the objectives of, the NASA Global Biology Research Program are given. The following issues were addressed: (1) geographic distribution of wetland parameters, (2) the processes of wetland material fluxes, and (3) the relation of local fluxes with global processes. Wetland inventorying and categorizing, gas-phase exchanges with the atmosphere, material exchange with the aquatic environment, and material storage in wetland sediments were identified as topics requiring further research.

1983-01-01

223

Forced Translocation of Polymer through Nanopore: Deterministic Model and Simulations  

NASA Astrophysics Data System (ADS)

We propose a new theoretical model of forced translocation of a polymer chain through a nanopore. We assume that DNA translocation at high fields proceeds too fast for the chain to relax, and thus the chain unravels loop by loop in an almost deterministic way. So the distribution of translocation times of a given monomer is controlled by the initial conformation of the chain (the distribution of its loops). Our model predicts the translocation time of each monomer as an explicit function of initial polymer conformation. We refer to this concept as ``fingerprinting''. The width of the translocation time distribution is determined by the loop distribution in initial conformation as well as by the thermal fluctuations of the polymer chain during the translocation process. We show that the conformational broadening ?t of translocation times of m-th monomer ?tm^1.5 is stronger than the thermal broadening ?tm^1.25 The predictions of our deterministic model were verified by extensive molecular dynamics simulations

Wang, Yanqian; Panyukov, Sergey; Liao, Qi; Rubinstein, Michael

2012-02-01

224

Characterization of Robertsonian translocations by using fluorescence in situ hybridization.  

PubMed

Fluorescence in situ hybridization with five biotin-labeled probes (three alphoid probes, a probe specific for beta-satellite sequences in all acrocentric chromosomes, and an rDNA probe) was used to characterize 30 different Robertsonian translocations, including three t(13;13); one t(15;15), four t(21;21), three t(13;14), two t(13;15), two (13;21), two t(13;22), one t(14;15), eight t(14;21), two t(14;22), and two t(21;22). Of 8 de novo homologous translocations, only one t(13;13) chromosome was interpreted as dicentric, while 19 of 22 nonhomologous Robertsonian translocations were dicentric. The three monocentric nonhomologous translocations included both of the t(13;21) and one t(21;22). Two of 26 translocations studied using the beta-satellite probe showed a positive signal, while rDNA was undetectable in 10 cases studied. These results indicate that most homologous Robertsonian translocations appear monocentric, while the bulk of nonhomologous translocations show two alphoid signals. A majority of the breakpoints localized using this analysis seem to be distal to the centromere and just proximal to the beta-satellite and nuclear-organizing regions. PMID:1729886

Wolff, D J; Schwartz, S

1992-01-01

225

Absence of Anaplastic Lymphoma Kinase Translocations in Signet Ring Cell Carcinomas of the Upper Gastrointestinal Tract  

PubMed Central

ABSTRACT BACKGROUND: Anaplastic lymphoma kinase (ALK) fusion oncogenes are present in multiple cancer types. The inversion of echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) genes on chromosome 2 is present in a subset of patients with non-small-cell lung cancer (NSCLC). ALK-rearranged lung cancers demonstrate a significantly higher incidence of signet ring cell histology than do ALK-negative tumors. Based on the histologic similarities of ALK-rearranged NSCLC and signet ring cell carcinomas (SRCCs) of the gastrointestinal tract, we hypothesized that SRCC of the upper gastrointestinal (GI) tract may also harbor ALK translocations. METHODS: Thirty-five formalin-fixed, paraffin-embedded (FFPE) diagnostic tissue specimens of SRCC or poorly differentiated adenocarcinoma with greater than 10% signet ring cell features originating from the upper GI tract were obtained and confirmed by a board-certified, GI pathologist. SRCC specimens were analyzed by fluorescence in situ hybridization (FISH) analysis, with an ALK (2p23) break-apart probe. RESULTS: The FISH analysis revealed no evidence of ALK translocation. All 35 (100%) SRCC specimens showed intact ALK FISH signals. CONCLUSIONS: These data indicate that, despite histologic similarities between SRCC of the upper GI tract and ALK-positive NSCLC, ALK translocations are unlikely to be a significant contributor to the molecular etiology of SRCC. Further genomic investigations are ongoing.

Miller, Jill; Peng, Zhihua; Wilcox, Rebecca; Evans, Mark; Ades, Steven

2014-01-01

226

?-PCR, A Simple Method to Detect Translocations and Insertion/Deletion Mutations.  

PubMed

PCR detection of chromosomal translocations and small insertion/deletion mutations is challenging when potential amplicon size varies greatly. Molecular diagnostic laboratories face such difficulties with the BCL2-IGH translocation in follicular lymphoma and with internal tandem duplication mutation of the FLT3 gene in leukemia, where breakpoints are widely distributed, mutations may be multiple, signal strength is low, and background noise is elevated. We developed a strategy, called ?-PCR, that ensures PCR specificity and identifies individual breakpoints. ?-PCR uses two forward primers (external and internal) and a reverse primer simultaneously. The internal primer functions as a probe with a defined distance ? from the external primer. For follicular lymphoma, we prepared upstream, BCL2-specific primers for potential breakpoints to pair with a common, downstream VLJH primer. Multiplexed PCR amplicons are sized by capillary electrophoresis. Each of the upstream pairs has a defined interval separating them that uniquely identifies the breakpoint. The presence of two amplicons with a defined size difference confirms validity of the rearrangement and identity of the specific breakpoint, even if signal strength is low. By testing 40 follicular lymphoma and 12 control specimens from formalin-fixed, paraffin-embedded (FFPE) blocks, we showed that multiplex ?-PCR is a simple, sensitive strategy to identify translocations with multiple breakpoints or partners. The strategy was also applied to detect minor leukemic clones with internal tandem duplication mutations and could have broader applications for other insertion/deletion and duplication mutations. PMID:21227398

Lin, Ming-Tseh; Tseng, Li-Hui; Rich, Roy G; Hafez, Michael J; Harada, Shuko; Murphy, Kathleen M; Eshleman, James R; Gocke, Christopher D

2011-01-01

227

Can hunting of translocated nuisance Canada geese reduce local conflicts?  

USGS Publications Warehouse

Resident Canada geese (Branta canadensis) nest or reside in the temperate latitudes of North America. In past years, translocation-the capture and subsequent release of geese at distant locations-has been used to establish resident goose populations and to reduce nuisance problems. However, with new special hunting seasons designed to target resident Canada geese, we can now evaluate translocation as a management tool when hunting is allowed at release sites. We selected 2 study sites, representative of urban and suburban locations with nuisance resident geese, in central and western New York, USA. In June 2003, we translocated 80 neck-banded adult geese, 14 radiomarked adult females, and 83 juveniles 150 km east and southwest from urban and suburban problem sites in western New York to state-owned Wildlife Management Areas. At these same capture sites, we used 151 neck-banded adult geese, 12 radiomarked females, and 100 juveniles as controls to compare dispersal movements and harvest vulnerability to translocated geese. All observations (n = 45) of translocated radiomarked geese were <20 km from release sites, in areas where hunting was permitted. Only 25 of 538 observations (4.6%) of radiomarked geese at control sites were in areas open to hunting. The remainder of observations occurred at nonhunting locations within 10 km of control sites. More translocated adult geese (23.8%) were harvested than control geese (6.6%; ??2 = 72.98, P = 0.0009). More translocated juvenile geese were harvested (22.9%) than juvenile controls (5.0%; ??2 = 72.30, P = 0.0005). Only 7 (8.8%) translocated adult geese returned to the original capture sites during Canada goose hunting seasons. Translocation of adult and juvenile geese in family groups may alleviate nuisance problems at conflict sites through increased harvest, reducing the number of birds returning in subsequent years.

Holevinski, R. A.; Malecki, R. A.; Curtis, P. D.

2006-01-01

228

Translocation of signalling proteins to the plasma membrane revealed by a new bioluminescent procedure  

PubMed Central

Background Activation by extracellular ligands of G protein-coupled (GPCRs) and tyrosine kinase receptors (RTKs), results in the generation of second messengers that in turn control specific cell functions. Further, modulation/amplification or inhibition of the initial signalling events, depend on the recruitment onto the plasma membrane of soluble protein effectors. High throughput methodologies to monitor quantitatively second messenger production, have been developed over the last years and are largely used to screen chemical libraries for drug development. On the contrary, no such high throughput methods are yet available for the other aspect of GPCRs regulation, i.e. protein translocation to the plasma membrane, despite the enormous interest of this phenomenon for the modulation of receptor downstream functions. Indeed, to date, the experimental procedures available are either inadequate or complex and expensive. Results Here we describe the development of a novel conceptual approach to the study of cytosolic proteins translocation to the inner surface of the plasma membrane. The basis of the technique consists in: i) generating chimeras between the protein of interests and the calcium (Ca2+)-sensitive, luminescent photo-protein, aequorin and ii) taking advantage of the large Ca2+ concentration [Ca2+] difference between bulk cytosolic and the sub-plasma membrane rim. Conclusion This approach, that keeps unaffected the translocation properties of the signalling protein, can in principle be applied to any protein that, upon activation, moves from the cytosol to the plasma membrane. Thus, not only the modulation of GPCRs and RTKs can be investigated in this way, but that of all other proteins that can be recruited to the plasma membrane also independently of receptor activation. Moreover, its automated version, which can provide information about the kinetics and concentration-dependence of the process, is also applicable to high throughput screening of drugs affecting the translocation process.

2011-01-01

229

The Extragalactic Radio Background  

NASA Technical Reports Server (NTRS)

The existence of an isotropic component of the high-latitude radio sky has been recognized for nearly fifty years, but has typically been assumed to be Galactic in origin. We use recent radio observations to test whether the observed high-latitude component could originate within either an extended Galactic halo or a more local "bubble" structure. The lack of significant polarization from the isotropic component, combined with the lack of significant correlation with the Galactic far-infrared emission, rule out an origin within the Galaxy. We conclude that an extragalactic origin is the only viable alternative for the bulk of the isotropic high-latitude emission. The extragalactic component is 2-3 times brighter than local (Galactic) emission towards the Galactic poles and is consistent with a power law in frequency with amplitude T(sub r) = 24.1 plus or minus 2.1 K and spectral index beta = -2.599 plus or minus 0.036 evaluated at reference frequency 310 MHz.

Kogut, A.; Fixsen, D. J.; Levin, S. M.; Limon, M.; Lubin, P. M.; Seiffert, M.; Singal, J.; Villela, T.; Wollack, E.; Wuensche, C. A.

2011-01-01

230

De Novo microdeletion on an inherited Robertsonian translocation chromosome: A cause for dysmorphism in the apparently balanced translocation carrier  

SciTech Connect

Robertsonian translocations are usually ascertained through abnormal children, making proposed phenotypic effects of apparently balanced translocations difficult to study in an unbiased way. From molecular genetic studies, though, some apparently balanced rearrangments are now known to be associated with phenotypic abnormalities resulting from uniparental disomy. Molecular explanations for other cases in which abnormality is seen in a balanced translocation carrier are being sought. In the present paper, an infant is described who has retarded growth, developmental delay, gross muscular hypotonia, slender habitus, frontal bossing, micrognathia, hooked nose, abundant wispy hair, and blue sclerae. Cytogenetically, she appeared to be a carrier of a balanced, paternally derived 14;21 Robertsonian translocation. Analysis of DNA polymorphisms showed that she had no paternal allele at the D14S13 locus (14q32). Study of additional DNA markers within 14q32 revealed that her previously undescribed phenotype results from an interstitial microdeletion within 14q32. Fluorescent in situ hybridization was used to show that this microdeletion had occurred de novo on the Robertsonian translocation chromosome. These observations may reactivate old suspicions of a causal association between Robertsonian translocations and de novo rearrangements in offspring; a systematic search for similar subcytogentic rearrangements in other families, in which there are phenotypically abnormal children with apparently balanced translocations, may be fruitful. The clinical and molecular genetic data presented also define a new contiguous gene syndrome due to interstitial 14q32 deletion. 42 refs., 4 figs., 1 tab.

Bonthron, D.T.; Smith, S.J.L.; Fantes, J.; Gosden, C.M.

1993-09-01

231

Adaptive control is enhanced by background estimation.  

PubMed

The automated control of physiological variables must often contend with an unknown and time-varying background (i.e., the output level corresponding to no input). To allow for simultaneous real-time identification of background as well as the parameters of an autoregressive moving average model with exogenous inputs (ARMAX model) during adaptive control, a "floating identifier" (FI) approach was developed which may be used with most recursive identification algorithms. This method separates input and output data into low- and high-frequency components. The high-frequency components are used to identify the ARMAX model parameters and the low-frequency components to identify background. This approach was evaluated in computer simulations and animal experiments comparing an adaptive controller coupled to the FI with the same controller coupled to two other standard least squares identifiers. In the animal experiments, sodium nitroprusside was used to control mean arterial pressure of anesthetized dogs in the presence of background changes. Results showed that with the FI, the controller performed satisfactorily, while with the other identifiers, it sometimes failed. It is concluded that the FI approach is useful when applying ARMAX-based adaptive controllers to systems in which a change in background is likely. PMID:2066141

Timmons, W D; Chizeck, H J; Katona, P G

1991-03-01

232

Backgrounds Data Center  

NASA Astrophysics Data System (ADS)

The Backgrounds Data Center (BDC) is the designated archive for backgrounds data collected by Ballistic Missile Defense Organization (BMDO) programs, some of which include ultraviolet sensors. Currently, the BDC holds ultraviolet data from the IBSS, UVPI, UVLIM, and FUVCAM sensors. The BDC will also be the prime archive for Midcourse Space Experiment (MSX) data and is prepared to negotiate with program managers to handle other datasets. The purpose of the BDC is to make data accessible to users and to assist them in analyzing it. The BDC maintains the Science Catalog Information Exchange System (SCIES) allowing remote users to log in, read or post notices about current programs, search the catalogs for datasets of interest, and submit orders for data. On-site facilities are also available for the analysis of data, and consist of VMS and UNIX workstations with access to software analysis packages such as IDL, IRAF, and Khoros. Either on-site or remotely, users can employ the BDC-developed graphical user interface called the Visual Interface for Space and Terrestrial Analysis (VISTA) to generate catalog queries and to display and analyze data. SCIES and VISTA permit nearly complete access to BDC services and capabilities without the need to be physically present at the data center.

Snyder, William A.; Gursky, Herbert; Heckathorn, Harry M.; Lucke, Bob L.; Dorland, Bryan N.; Kessel, R. A.; Berg, S. L.; Dombrowski, E. G.

1994-09-01

233

The Backgrounds Data Center  

NASA Technical Reports Server (NTRS)

The Strategic Defense Initiative Organization has created data centers for midcourse, plumes, and backgrounds phenomenologies. The Backgrounds Data Center (BDC) has been designated as the prime archive for data collected by SDIO programs. The BDC maintains a Summary Catalog that contains 'metadata,' that is, information about data, such as when the data were obtained, what the spectral range of the data is, and what region of the Earth or sky was observed. Queries to this catalog result in a listing of all data sets (from all experiments in the Summary Catalog) that satisfy the specified criteria. Thus, the user can identify different experiments that made similar observations and order them from the BDC for analysis. On-site users can use the Science Analysis Facility (SAFE for this purpose. For some programs, the BDC maintains a Program Catalog, which can classify data in as many ways as desired (rather than just by position, time, and spectral range as in the Summary Catalog). For example, data sets could be tagged with such diverse parameters as solar illumination angle, signal level, or the value of a particular spectral ratio, as long as these quantities can be read from the digital record or calculated from it by the ingest program. All unclassified catalogs and unclassified data will be remotely accessible.

Snyder, W. A.; Gursky, H.; Heckathorn, H. M.; Lucke, R. L.; Berg, S. L.; Dombrowski, E. G.; Kessel, R. A.

1993-01-01

234

Energy-dependent intracellular translocation of proparathormone.  

PubMed

We previously suggested that after synthesis, proparathormone is transferred from rough endoplasmic reticulum to the Golgi region where its conversion to parathormone occurs. We have attempted to define more closely this transfer process. In the first type of study, bovine parathyroid slices were incubated with [3H]leucine for 10 min and then radioisotope labeling was restricted by addition of a large excess of nonradioactive leucine. Under these conditions, more than 90% of the initially labeled proparathormone was converted to parathormone in 40 min. Lowered temperature in the chase period markedly inhibited the conversion. Several chemical agents were employed individually in the chase period to examine their effect on the conversion process. Antimycin A, dinitrophenol, oligomycin, and anaerobiosis (N2) inhibited the conversion, whereas sodium flouride and cycloheximide had no effect. In the second type of study, parathyroid slices were incubated with [3H]leucine for the entire incubation period. Lowered temperature and inhibitors of energy metabolism and microtubular function all lengthened the interval (lag) between the initial synthesis of [3H]parathormone. Cycloheximide, Tris, and chloroquine decreased the rates of protein synthesis and conversion, respectively, but none had any effect on the lag. We interpret the lag to represent the time of transit for proparathormone from rough endoplasmic reticulum to the Golgi region. We conclude that this transfer process is independent of the synthesis of the prohormone and its conversion to the hormone. Moreover, this translocation requires metabolic energy and appears to be mediated by microtubules. PMID:556615

Chu, L L; MacGregor, R R; Cohn, D V

1977-01-01

235

Bacterial Translocation - Impact on the Adipocyte Compartment  

PubMed Central

Over the last decade it became broadly recognized that adipokines and thus the fat tissue compartment exert a regulatory function on the immune system. Our own group described the pro-inflammatory function of the adipokine leptin within intestinal inflammation in a variety of animal models. Following-up on this initial work, the aim was to reveal stimuli and mechanisms involved in the activation of the fat tissue compartment and the subsequent release of adipokines and other mediators paralleled by the infiltration of immune cells. This review will summarize the current literature on the possible role of the mesenteric fat tissue in intestinal inflammation with a focus on Crohn’s disease (CD). CD is of particular interest in this context since the transmural intestinal inflammation has been associated with a characteristic hypertrophy of the mesenteric fat, a phenomenon called “creeping fat.” The review will address three consecutive questions: (i) What is inducing adipocyte activation, (ii) which factors are released after activation and what are the consequences for the local fat tissue compartment and infiltrating cells; (iii) do the answers generated before allow for an explanation of the role of the mesenteric fat tissue within intestinal inflammation? With this review we will provide a working model indicating a close interaction in between bacterial translocation, activation of the adipocytes, and subsequent direction of the infiltrating immune cells. In summary, the models system mesenteric fat indicates a unique way how adipocytes can directly interact with the immune system.

Kruis, Tassilo; Batra, Arvind; Siegmund, Britta

2013-01-01

236

Multiscale model of platelet translocation and collision  

NASA Astrophysics Data System (ADS)

The tethering of platelets on the injured vessel surface mediated by glycoprotein Ib? (GPIb?) - Von Willebrand factor (vWF) bonds, as well as the interaction between flowing platelets and adherent platelets, are two key events that take place immediately following blood vessel injury. This early-stage platelet deposition and accumulation triggers the initiation of hemostasis, a self-defensive mechanism to prevent the body from excessive blood loss. To understand and predict this complex process, one must integrate experimentally determined information on the mechanics and biochemical kinetics of participating receptors over very small time frames (1-1000 ?s) and length scales (10-100 nm), to collective phenomena occurring over seconds and tens of microns. In the present study, a unique three dimensional multiscale computational model, Platelet Adhesive Dynamics (PAD), was applied to elucidate the unique physics of (i) a non-spherical, disk-shaped platelet interacting and tethering onto the damaged vessel wall followed by (ii) collisional interactions between a flowing platelet with a downstream adherent platelet. By analyzing numerous simulations under different physiological conditions, we conclude that the platelet's unique spheroid-shape provides heterogeneous, orientation-dependent translocation (rolling) behavior which enhances cell-wall interactions. We also conclude that platelet-platelet near field interactions are critical for cell-cell communication during the initiation of microthrombi. The PAD model described here helps to identify the physical factors that control the initial stages of platelet capture during this process.

Wang, Weiwei; Mody, Nipa A.; King, Michael R.

2013-07-01

237

Unbalanced jumping translocation involving 3q in myeloproliferative disease.  

PubMed

An 87-year-old woman was diagnosed with unclassified myeloproliferative disease having an acquired jumping translocation with the long arm of chromosome 3 translocating to the short arm telomeric region of chromosome 8 (major clone) and the long arm telomeric region of chromosome 10 (minor clone). Each abnormal clone was also associated with an extra copy of chromosome 8. Although there was no evidence of transformation to an acute leukemia, the patient deteriorated until her demise 7 months after disease presentation. There have been fewer than 70 cases of acquired jumping translocations reported in the literature. To our knowledge, this is the first acquired jumping translocation case to be reported in a patient with myeloproliferative disease. PMID:18509766

McGrattan, Peter; Humphreys, Mervyn; Hull, Donald

2009-01-01

238

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2013 CFR

...identified cytologically through analysis of diakinesis metaphase...fatalities which would prevent a meaningful evaluation) or shall be the...and subsequent cytological analysis of suspect progeny; the...translocation. (ii) Cytological analysis. For...

2013-07-01

239

Sequence Dependence of DNA Translocation through a Nanopore  

NASA Astrophysics Data System (ADS)

We investigate the dynamics of DNA translocation through a nanopore using 2D Langevin dynamics simulations, focusing on the dependence of the translocation dynamics on the details of DNA sequences. The DNA molecules studied in this work are built from two types of bases A and C, which have been shown previously to have different interactions with the pore. We study DNA with repeating blocks AnCn for various values of n and find that the translocation time depends strongly on the block length 2n as well as on the orientation of which base enters the pore first. Thus, we demonstrate that the measurement of translocation dynamics of DNA through a nanopore can yield detailed information about its structure. We have also found that the periodicity of the block sequences is contained in the periodicity of the residence time of the individual nucleotides inside the pore.

Luo, Kaifu; Ala-Nissila, Tapio; Ying, See-Chen; Bhattacharya, Aniket

2008-02-01

240

Dominant-Lethal Mutation and Heritable Translocation Tests in Mice.  

National Technical Information Service (NTIS)

The spontaneous occurrence of chromosome breakage-related genetic anomalies in humans is estimated to be 0.24%, not including spontaneous abortions. More balanced reciprocal translocations are being discovered among mentally handicapped individuals. Chrom...

W. M. Generoso

1980-01-01

241

Haploinsufficiency of Activation-Induced Deaminase for Antibody Diversification and Chromosome Translocations both In Vitro and In Vivo  

PubMed Central

The humoral immune response critically relies on the secondary diversification of antibodies. This diversification takes places through somatic remodelling of the antibody genes by two molecular mechanisms, Class Switch Recombination (CSR) and Somatic Hypermutation (SHM). The enzyme Activation Induced Cytidine Deaminase (AID) initiates both SHM and CSR by deaminating cytosine residues on the DNA of immunoglobulin genes. While crucial for immunity, AID-catalysed deamination is also the triggering event for the generation of lymphomagenic chromosome translocations. To address whether restricting the levels of AID expression in vivo contributes to the regulation of its function, we analysed mice harbouring a single copy of the AID gene (AID+/?). AID+/? mice express roughly 50% of normal AID levels, and display a mild hyperplasia, reminiscent of AID deficient mice and humans. Moreover, we found that AID+/? cells have an impaired competence for CSR and SHM, which indicates that AID gene dose is limiting for its physiologic function. We next evaluated the impact of AID reduction in AID+/? mice on the generation of chromosome translocations. Our results show that the frequency of AID-promoted c-myc/IgH translocations is reduced in AID+/? mice, both in vivo and in vitro. Therefore, AID is haploinsufficient for antibody diversification and chromosome translocations. These findings suggest that limiting the physiologic levels of AID expression can be a regulatory mechanism that ensures an optimal balance between immune proficiency and genome integrity.

Sernandez, Isora V.; de Yebenes, Virginia G.; Dorsett, Yair; Ramiro, Almudena R.

2008-01-01

242

Complex Variant 15;17 Translocations in Acute Promyelocytic Leukemia  

Microsoft Academic Search

Complex variant 15;17 translocations are increasingly recognized in acute promyelocytic leukemia (APL). We report a novel three-way translocation in APL involving chromosomes 15, 17, and X in the form of t(X;17;15)(q13;q12;q21). Southern blot analysis showed retinoic acid receptor ? (RARA) gene rearrangement at intron 2. Clinical and morphologic findings are typical of APL, and a complete remission was attained with

T. S. K Wan; C. S Chim; C. K So; L. C Chan; S. K Ma

1999-01-01

243

Controlled translocation of DNA segments through nanoelectrode gaps  

SciTech Connect

Molecular dynamics simulations show that electrophoresis of DNA segments through a nanoscale electrode gap can be controlled by applying appropriate biased voltages in the transmembrane direction. The translocation velocities are dependent on both the DNA molecular weight and nucleotide structure. Application of alternating driving fields results in oscillatory motion of DNA inside the gap. Interruption of the driving field can effectively pause the translocation of DNA segments. Results from this work are useful for designing novel sequencing devices.

Zhao, Xiongce [ORNL; Payne, Christina M [Vanderbilt University; Cummings, Peter T [ORNL

2008-01-01

244

Meiotic analysis of two human reciprocal X-autosome translocations  

Microsoft Academic Search

Two cases of human reciprocal X-autosome translocation, t(X;12) and t(X;2), are described in sterile males, along with meiotic findings. Each carrier had inherited the translocation from his mother. Both showed azoospermia and germ-cell maturation arrest at the primary spermatocyte level, with most cells being arrested at the pachytene stage. A few metaphase I (MI) divisions were found, with occasional metaphase

B. Quack; R. M. Speed; J. M. Luciarni; B. Noel; M. Guichaoua; A. C. Chandley

1988-01-01

245

Diphtheria toxin translocation across cellular membranes is regulated by sphingolipids  

Microsoft Academic Search

Diphtheria toxin is translocated across cellular membranes when receptor-bound toxin is exposed to low pH. To study the role of sphingolipids for toxin translocation, both a mutant cell line lacking the first enzyme in de novo sphingolipid synthesis, serine palmitoyltransferase, and a specific inhibitor of the same enzyme, myriocin, were used. The serine palmitoyltransferase-deficient cell line (LY-B) was found to

Bjørn Spilsberg; Kentaro Hanada; Kirsten. Sandvig

2005-01-01

246

Molecular studies of translocations and trisomy involving chromosome 13  

SciTech Connect

Twenty-four cases of trisomy 13 and one case with disomy 13, but a de novo dic(13,13)(p12p12) chromosome, were examined with molecular markers to determine the origin of the extra (or rearranged) chromosome. Twenty-one of 23 informative patients were consistent with a maternal origin of the extra chromosome. Lack of a third allele at any locus in both paternal origin cases indicate a somatic duplication of the paternal chromosome occurred. Five cases had translocation trisomy. The patient with a paternal rob(13q14q) had a maternal meiotic origin of the trisomy; thus, the paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13q14q) carrier and most trisomies are maternal in origin, this result should not be surprising; however, it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. Lack of a third allele at any locus in one of the three t(13q13q) cases indicates that it was most likely an isochromosome of postmeiotic origin, whereas the other two cases showed evidence of recombination. One balanced (nontrisomic) case with a nonmosaic 45, -13, -13, +t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologues, as has been found for all balanced homologous Robertsonian translocations so far investigated. Thus, it is also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. Despite a maternal origin of the trisomy, we cannot therefore infer anything about the parental origin of the chromosomes 13 and 14 involved in the translocation in the de novo t(13q14q) case nor for the two t(13;13) chromosomes showing a meiotic origin of the trisomy. 30 refs., 1 fig., 2 tabs.

Robinson, W.P.; Bernasconi, F.; Dutly, F.; Schinzel, A.A. [Univ. of British Columbia, Vancouver (Canada)] [and others] [Univ. of British Columbia, Vancouver (Canada); and others

1996-01-11

247

Driven translocation of a polymer: Fluctuations at work  

NASA Astrophysics Data System (ADS)

The impact of thermal fluctuations on the translocation dynamics of a polymer chain driven through a narrow pore has been investigated theoretically and by means of extensive molecular dynamics (MD) simulation. The theoretical consideration is based on the so-called velocity Langevin (V-Langevin) equation which determines the progress of the translocation in terms of the number of polymer segments, s(t), that have passed through the pore at time t due to a driving force f. The formalism is based only on the assumption that, due to thermal fluctuations, the translocation velocity v=?(t) is a Gaussian random process as suggested by our MD data. With this in mind we have derived the corresponding Fokker-Planck equation (FPE) which has a nonlinear drift term and diffusion term with a time-dependent diffusion coefficient D(t). Our MD simulation reveals that the driven translocation process follows a super diffusive law with a running diffusion coefficient D(t)?t? where ?<1. This finding is then used in the numerical solution of the FPE which yields an important result: For comparatively small driving forces fluctuations facilitate the translocation dynamics. As a consequence, the exponent ? which describes the scaling of the mean translocation time with the length N of the polymer, ?N? is found to diminish. Thus, taking thermal fluctuations into account, one can explain the systematic discrepancy between theoretically predicted duration of a driven translocation process, considered usually as a deterministic event, and measurements in computer simulations. In the nondriven case, f=0, the translocation is slightly subdiffusive and can be treated within the framework of fractional Brownian motion (fBm).

Dubbeldam, J. L. A.; Rostiashvili, V. G.; Milchev, A.; Vilgis, T. A.

2013-03-01

248

Discrepancy between GLUT4 translocation and glucose uptake after ischemia  

Microsoft Academic Search

Objective: Low-flow ischemia results in glucose transporter translocation and in increased glucose uptake. After total ischemia in rat heart, we found no increase in glucose uptake. Here we test the hypothesis that total ischemia is associated with decreased activation of GLUT4 despite translocation. Methods: Isolated working hearts (n=70, Sprague–Dawley rats) were perfused for 70 min at physiological workload with Krebs–Henseleit

Vlad Zaha; Roland Nitschke; Heike Göbel; Ulrich Fischer-Rasokat; Christoph Zechner; Torsten Doenst

2005-01-01

249

Specificity of streptolysin O in cytolysin-mediated translocation  

Microsoft Academic Search

Summary Cytolysin-mediated translocation (CMT) is a recently described process in the Gram-positive pathogen Streptococcus pyogenes that translocates an effector protein of streptococcal origin into the cytoplasm of a host cell. At least two proteins participate in CMT, the pore-forming molecule streptolysin O (SLO) and an effector protein with the characteristics of a signal transduction protein, the Streptococcus pyogenes NAD-glycohydrolase (SPN).

Michael A. Meehl; Michael G. Caparon

2004-01-01

250

Translocating Adult Pacific Lamprey within the Columbia River Basin: State of the Science  

Microsoft Academic Search

The Pacific lamprey (Entosphenus tridentatus) is in decline in the Columbia River Basin, and translocating adult lamprey to bypass difficult migration corridors has been implemented since 2000. We describe and report results from two current translocation programs, provide context for use of translocation, and discuss potential benefits, risks, and uncertainties. Both translocation programs appear to have increased the number of

David L. Ward; Benjamin J. Clemens; David Clugston; Aaron D. Jackson; Mary L. Moser; Chris Peery; David P. Statler

2012-01-01

251

Holography for Schrödinger backgrounds  

NASA Astrophysics Data System (ADS)

We discuss holography for Schrödinger solutions of both topologically massive gravity in three dimensions and massive vector theories in ( d + 1) dimensions. In both cases the dual field theory can be viewed as a d-dimensional conformal field theory (two dimensional in the case of TMG) deformed by certain operators that respect the Schrödinger symmetry. These operators are irrelevant from the viewpoint of the relativistic conformal group but they are exactly marginal with respect to the non-relativistic conformal group. The spectrum of linear fluctuations around the background solutions corresponds to operators that are labeled by their scaling dimension and the lightcone momentum k v . We set up the holographic dictionary and compute 2-point functions of these operators both holographically and in field theory using conformal perturbation theory and find agreement. The counterterms needed for holographic renormalization are non-local in the v lightcone direction.

Guica, Monica; Skenderis, Kostas; Taylor, Marika; van Rees, Balt C.

2011-02-01

252

Background level care.  

PubMed

The framework enabled by the International Caries Detection and Assessment System to allow appropriate, patient-centred caries management includes a frequently encountered scenario in which a comprehensive assessment of the teeth and the patient reveals no lesions in need of active preventive or operative care. The issue addressed here is: what background care is appropriate for patients attending a dental practice for routine caries care who, at present, appear to have no active or progressing caries lesions? It is proposed that, in addition to the use of criteria for lesion extent, treatment planning systems should also express the results of lesion assessments in terms of background level care (BLC), preventive treatment options and operative treatment options. The specific treatment options recommended for specific lesions and patients will depend upon a variety of other factors, including lesion activity, monitoring lesion behaviour over time and a range of other prognostic factors. Over recent decades, there has been comparatively little focus on appropriate BLC in a general practice setting. There are a range of issues around the need to support caries prevention and health maintenance from a behavioural and patient-focussed perspective. Even if a patient is deemed to be at low risk of future caries at a particular examination, there is a need for maintenance care. Intrinsic issues which need to be managed for both patients and their caries lesions in this patient group are: (1) the possibility of a change in caries risk status and (2) the impact of incorrect lesion assessments/diagnoses. PMID:19494681

Pitts, N B

2009-01-01

253

Genic Heterozygosity and Variation in Permanent Translocation Heterozygotes of the OENOTHERA BIENNIS Complex  

PubMed Central

Genic heterozygosity and variation were studied in the permanent translocation heterozygotes Oenothera biennis I, Oe. biennis II, Oe. biennis III, Oe. strigosa, Oe. parviflora I, Oe. parviflora II, and in the related bivalent formers Oe. argillicola and Oe. hookeri. From variation at 20 enzyme loci, we find that translocation heterozygosity for the entire chromosome complex is accompanied by only moderate levels of genic heterozygosity: 2.8% in Oe. strigosa, 9.5% in Oe. biennis and 14.9% in Oe. parviflora. Inbred garden strains of Oe. argillicola exhibited 8% heterozygosity; neither garden nor wild strains of Oe. hookeri displayed heterozygosity and only a single allozyme genotype was found. The mean number of alleles per locus is only 1.30 in Oe. strigosa, 1.40 in Oe. biennis, and 1.55 in Oe. parviflora, compared to 1.40 in Oe. argillicola. Clearly, the ability to accumulate and/or retain heterozygosity and variability has not been accompanied by extraordinary levels of either. Clinal variation is evident at some loci in each ring-former. A given translocation complex may vary geographically in its allozymic constitution. From gene frequencies, Oe. biennis I, II, and III, Oe. strigosa and Oe. hookeri are judged to be very closely related, whereas Oe. argillicola seems quite remote; Oe. parviflora is intermediate to the two phylads. Gene frequencies also suggest that Oe. argillicola diverged from the Euoenothera progenitor about 1,000,000 years ago, whereas most of the remaining evolution in the complex has occurred within the last 150,000 years.

Levy, Morris; Levin, Donald A.

1975-01-01

254

Isochromosome Yp and jumping translocation of Yq resulting in five cell lines in an infertile male: a case report and review of the literature  

PubMed Central

Background Jumping translocations are a rare type of mosaicism in which the same portion of one donor chromosome is translocated to several recipient chromosomes. Constitutional forms of jumping translocations are rare, and the 48 cases reported to date have been associated with both normal and abnormal phenotypes. Concurrence of isochromosome (i) of one arm and translocation of the other is also rare, with seven reported cases. We describe a unique case involving concurrence of i(Yp) and a jumping translocation of Yq to the telomere of chromosomes 12q and 17q, which resulted in five cell lines. Case presentation The patient, an otherwise healthy 35-year-old man, was referred for cytogenetic studies because of absolute azoospermia. He had elevated levels of follicle stimulating hormone and luteinizing hormone, consistent with abnormal spermatogenesis, and decreased levels of free testosterone and inhibin B. G-banded chromosome analysis revealed a mosaic male karyotype involving five abnormal cell lines. One of the cell lines showed loss of chromosome Y and presence of i(Yp) as the sole abnormality. Three cell lines exhibited jumping translocation: two involved 17qter, and the other involved 12qter as the recipient and Yq as the common donor chromosome. One of the cell lines with der(17) additionally showed i(Yp). The other der(17) and der(12) cell lines had a missing Y chromosome. All five cell lines were confirmed by FISH. Subtelomric FISH study demonstrated no loss of chromosome material from the recipient chromosomes at the translocation junctions. Conclusions We postulate that a postzygotic pericentromeric break of the Y chromosome led to formation of isochromosome Yp, whereas Yq formed a jumping translocation through recombination between its internal telomere repeats and telomeric repeats of recipient chromosomes. This in turn led to either pairing or an exchange at the complimentary sequences. Such translocation junctions appear to be unstable and to result in a jumping translocation. Cryptic deletion or disruption of AZF (azoospermic factor) genes at Yq11 during translocation or defective pairing of X and Y chromosomes during meiosis, with abnormal sex vesicle formation and consequent spermatogenetic arrest, might be the main cause of the azoospermia in our patient.

2013-01-01

255

Translocation of the Palila, an endangered Hawaiian honeycreeper  

USGS Publications Warehouse

The Palila Loxioides bailleui is an endangered Hawaiian honeycreeper that is restricted to high-elevation dry woodlands on Mauna Kea volcano, Hawaii. Palila are absent or occur in small numbers throughout most of their historic range because of habitat loss, predation and avian disease. The Paula's habitat is regenerating as a result of feral ungulate control, but the species is likely to be slow in recolonizing former ranges because of strong site tenacity. In March 1993, we translocated 35 Palila to Kanakaleonui on the eastern slope of Mauna Kea to determine whether we could speed recovery by releasing adult birds in new areas where predators were controlled. At least two pairs of translocated Palila successfully nested at the release site during their first breeding season, and two other pairs constructed nests. The density of Palila at Kanakaleonui in the three years following the translocation was higher than that before translocation. Approximately half of the translocated birds remained at the release site for 2-6 weeks and then homed back to their capture site, >20 km away. Translocations of adult birds and release of captive-reared juvenile Palila, in combination with additional habitat restoration, may be an effective management tool for speeding the recovery of this species.

Fancy, S. G.

1997-01-01

256

Dynamics of polymer translocation rectified by attractive binding particles  

NASA Astrophysics Data System (ADS)

We study translocation of flexible homopolymer chains through a nanopore in presence of attractive particles those bind reversibly on the trans part of the chain and responsible for successful translocation using Langevin dynamics simulation. We study the mean first passage time (MFPT) as a function of the density ?att and strength ?att of the attractive particles respectively and find that it is qualitatively different compared to the results obtained for straight(rigid) chains^1. Further, we find the average translocation time ˜N^1.5 which is faster than the lower bound predicted by simple one dimensional Langevin equation. Finally, we find that for certain combination of ?att and ?att the translocation is most efficient. We interpret it as a resonant assisted activated translocation. We discuss relevance of our studies in biological translocation processes.^1R. Zandi, D. Reguera, J. Rudnick and W. M. Gelbart, Proc. Natl. Acad. Sci. USA 100 8649 (2003).^2W. Sung and P. J. Park, Phys. Rev. Lett. 77, 783 (1996).

Bhattacharya, Aniket; Lorscher, Christopher; Ala-Nissila, Tapio; Sung, Wokyung

2010-03-01

257

Millisecond dynamics of RNA polymerase II translocation at atomic resolution.  

PubMed

Transcription is a central step in gene expression, in which the DNA template is processively read by RNA polymerase II (Pol II), synthesizing a complementary messenger RNA transcript. At each cycle, Pol II moves exactly one register along the DNA, a process known as translocation. Although X-ray crystal structures have greatly enhanced our understanding of the transcription process, the underlying molecular mechanisms of translocation remain unclear. Here we use sophisticated simulation techniques to observe Pol II translocation on a millisecond timescale and at atomistic resolution. We observe multiple cycles of forward and backward translocation and identify two previously unidentified intermediate states. We show that the bridge helix (BH) plays a key role accelerating the translocation of both the RNA:DNA hybrid and transition nucleotide by directly interacting with them. The conserved BH residues, Thr831 and Tyr836, mediate these interactions. To date, this study delivers the most detailed picture of the mechanism of Pol II translocation at atomic level. PMID:24753580

Silva, Daniel-Adriano; Weiss, Dahlia R; Pardo Avila, Fátima; Da, Lin-Tai; Levitt, Michael; Wang, Dong; Huang, Xuhui

2014-05-27

258

Surface modification of graphene nanopores for protein translocation.  

PubMed

Studies of DNA translocation through graphene nanopores have revealed their potential for DNA sequencing. Here we report a study of protein translocation through chemically modified graphene nanopores. A transmission electron microscope (TEM) was used to cut nanopores with diameters between 5 and 20 nm in multilayer graphene prepared by chemical vapor deposition (CVD). After oxygen plasma treatment, the dependence of the measured ionic current on salt concentration and pH was consistent with a small surface charge induced by the formation of carboxyl groups. While translocation of gold nanoparticles (10 nm) was readily detected through such treated pores of a larger diameter, translocation of the protein ferritin was not observed either for oxygen plasma treated pores, or for pores modified with mercaptohexadecanoic acid. Ferritin translocation events were reliably observed after the pores were modified with the phospholipid-PEG (DPPE-PEG750) amphiphile. The ion current signature of translocation events was complex, suggesting that a series of interactions between the protein and pores occurs during the process. PMID:24231385

Shan, Y P; Tiwari, P B; Krishnakumar, P; Vlassiouk, I; Li, W Z; Wang, X W; Darici, Y; Lindsay, S M; Wang, H D; Smirnov, S; He, J

2013-12-13

259

Polymer translocation in a double-force arrangement.  

PubMed

Using Langevin dynamics simulations, we investigate the translocation dynamics of an externally driven polymer chain through a nanopore, where a pulling force F is exerted on the first monomer whilst there is an opposing force F(E) < F within the pore. Such a double-force arrangement has been proposed recently to allow better dynamical control of the translocation process in order to sequence biopolymers. We find that in the double-force arrangement translocation becomes slower as compared to the case under a single monomer pulling force of magnitude F-F(E), but scaling of the translocation time as a function of the chain length tau approximately N2 does not change. The waiting time tau(m) for monomer m to exit the pore is found to be a monotonically increasing function of the bead number almost until m approximately N , which indicates relatively well-defined slowing down and control of the chain velocity during translocation. We also study the waiting time distributions for the beads in the chain, and characterize in detail fluctuations in the bead positions and their transverse position coordinates during translocation. These data should be useful in estimating position-dependent sequencing errors in double-force experiments. PMID:19326157

Ollila, S T T; Luo, K F; Ala-Nissila, T; Ying, S-C

2009-04-01

260

Bcl-XL translocation in renal tubular epithelial cells in vitro protects distal cells from oxidative stress  

Microsoft Academic Search

Bcl-XL translocation in renal tubular epithelial cells in vitro protects distal cells from oxidative stress.BackgroundThe molecular pathogenesis of different sensitivities of the renal proximal and distal tubular cell populations to ischemic injury, including ischemia-reperfusion (IR)-induced oxidative stress, is not well-defined. An in vitro model of oxidative stress was used to compare the survival of distal [Madin-Darby canine kidney (MDCK)] and

Leila Cuttle; Xiao-Ju Zhang; Zoltan H. Endre; Clay Winterford; Glenda C. Gobe

2001-01-01

261

Fusion of the NUP98 gene with the LEDGF/p52 gene defines a recurrent acute myeloid leukemia translocation  

PubMed Central

Background The NUP98 gene is involved in multiple rearrangements in haematological malignancy. The leukemic cells in an acute myeloid leukemia (AML) patient with a t(9;11)(p22;p15) were recently shown to have a fusion between the NUP98 gene and the LEDGF gene but it was not demonstrated that this fusion was recurrent in other leukaemia patients with the same translocation. Results We used RT-PCR to analyse the leukemic cells from an AML patient who presented with a cytogenetically identical translocation as the sole chromosomal abnormality. A NUP98-LEDGF fusion transcript was observed and confirmed by sequencing. The reciprocal transcript was also observed. The fusion transcript was not detectable during remission and recurred at relapse. The breakpoints in the NUP98 and LEDGF genes were different to those previously reported. The NUP98 breakpoint occurs in the intron between exons 8 and 9. It is the most 5' breakpoint reported in a translocation involving the NUP98 gene. All of the LEDGF gene is included in the fusion except for exon 1 which codes for the first 24 amino terminal amino acids. Conclusions Our results show that fusion of the NUP98 and LEDGF genes is a new recurrent translocation in AML.

Hussey, Damian J; Moore, Sarah; Nicola, Mario; Dobrovic, Alexander

2001-01-01

262

Gaussianity of LISA's confusion backgrounds  

SciTech Connect

Data analysis for the proposed Laser Interferometer Space Antenna (LISA) will be complicated by the huge number of sources in the LISA band. In the frequency band {approx}10{sup -4}-2x10{sup -3} Hz, galactic white dwarf binaries (GWDBs) are sufficiently dense in frequency space that it will be impossible to resolve most of them, and ''confusion noise'' from the unresolved Galactic binaries will dominate over instrumental noise in determining LISA's sensitivity to other sources in that band. Confusion noise from unresolved extreme-mass-ratio inspirals (EMRIs) could also contribute significantly to LISA's total noise curve. To date, estimates of the effect of LISA's confusion noise on matched-filter searches and their detection thresholds have generally approximated the noise as Gaussian, based on the central limit theorem. However in matched-filter searches, the appropriate detection threshold for a given class of signals may be located rather far out on the tail of the signal-to-noise probability distribution, where a priori it is unclear whether the Gaussian approximation is reliable. Using the Edgeworth expansion and the theory of large deviations, we investigate the probability distribution of the usual matched-filter detection statistic, far out on the tail of the distribution. We apply these tools to four somewhat idealized versions of LISA data searches: searches for EMRI signals buried in GWDB confusion noise, and searches for massive black hole binary signals buried in (i) GWDB noise, (ii) EMRI noise, and (iii) a sum of EMRI noise and Gaussian noise. Assuming reasonable short-distance cutoffs in the populations of confusion sources (since the very closest and hence strongest sources will be individually resolvable), modifications to the appropriate detection threshold, due to the non-Gaussianity of the confusion noise, turn out to be quite small for realistic cases. The smallness of the correction is partly due to the fact that these three types of sources evolve on quite different time scales, so no single background source closely resembles any search template. We also briefly discuss other types of LISA searches where the non-Gaussianity of LISA's confusion backgrounds could perhaps have a much greater impact on search reliability and efficacy.

Racine, Etienne [Department of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125 (United States); Cutler, Curt [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)

2007-12-15

263

Inhibition of Intestinal Bacterial Translocation with Rifaximin Modulates Lamina propria Monocytic Cells Reactivity and Protects against Inflammation in a Rodent Model of Colitis  

Microsoft Academic Search

Background: A modification of the intestinal flora and an increased bacterial translocation is a common finding in patients with inflammatory bowel disease as well as in animal model of colitis. Rifaximin, a non-absorbable derivative of rifamycin, is an effective antibiotic that acts by inhibiting bacterial ribonucleic acid synthesis. Aims: In the present study, we investigated the effect of the administration

Stefano Fiorucci; Eleonora Distrutti; Andrea Mencarelli; Miriam Barbanti; Ernesto Palazzini; Antonio Morelli

2002-01-01

264

Specific chromosomal IG translocations have different prognoses in chronic lymphocytic leukemia  

PubMed Central

Background Chromosomal translocations are usually analyzed as a single entity, and are associated with a poor outcome in chronic lymphocytic leukemia. Translocations involving immunoglobulin genes are recurrent, but uncommon (<5%), and their individual prognosis is not clear. The two most frequent partners are BCL2 (18q21) and BCL3 (19q13). Designs and methods Herein, 75 cases are reported of chronic lymphocytic leukemia and t(14;18) (BCL2-CLLs). Our series benefits from morphological, immunological and cytogenetical reviews. The IGHV status analyses were performed by referring laboratories. Comparison was made with our previously published series of chronic lymphocytic leukemia patients with t(14;19) (BCL3-CLLs, n=29). Results Compared with BCL3-CLLs, lymphocytosis was lower in BCL2-CLLs (p<0.008), and splenomegaly was less frequent (p<0.0001). There were more “typical” morphologies (p<0.005) and Matutes scores >4 (p<0.001) in the BCL2-CLLs group, and less CD38 expression (p<0.04). More variant BCL2-translocations were observed (t(18;22), n=11; 2t(2;18), n=2; p<0.02), and BCL2-translocation was frequently single (p<0.002). Complex karyotypes (p<0.02), trisomy 12 (p<0.03), 6q deletion (p<0.002) and TP53 deletion (p<0.02) were less frequent in BCL2-CLLs, whereas 13q deletion was more frequent (p<0.005). The IGHV gene was frequently mutated in BCL2-CLLs (p<0.0001). Treatment-free survival was longer in BCL2-CLLs (p<0.0001). Conclusions BCL2-CLL.S express CD5 and lack expression of CD38, and have a Matutes score ?4, frequent trisomy 12, no ATM and 6q deletions, and a mutated IGHV status. Compared to BCL3-CLLs, BCL2-CLLs are much less aggressive; indicating that identifying individual translocations and cytogenetic partners would allow improved patient stratification.

Nguyen-Khac, Florence; Chapiro, Elise; Lesty, Claude; Grelier, Aurore; Luquet, Isabelle; Radford-Weiss, Isabelle; Lefebvre, Christine; Fert-Ferrer, Sandra; Callet-Bauchu, Evelyne; Lippert, Eric; Raggueneau, Victoria; Michaux, Lucienne; Barin, Carole; Collonge-Rame, Marie-Agnes; Mugneret, Francine; Eclache, Virginie; Taviaux, Sylvie; Dastugue, Nicole; Richebourg, Steven; Struski, Stephanie; Talmant, Pascaline; Baranger, Laurence; Gachard, Nathalie; Gervais, Carine; Quilichini, Benoit; Settegrana, Catherine; Maloum, Karim; Davi, Frederic; Merle-Beral, Helene

2011-01-01

265

Computer simulation of viral-assembly and translocation  

NASA Astrophysics Data System (ADS)

We investigated four different problems using coarse grained computational models : self-assembly of single stranded (ss) DNA virus, ejection dynamics of double stranded(ds) DNA from phages, translocation of ssDNA through MspA protein pore, and segmental dynamics of a polymer translocating through a synthetic nanopore. In the first part of the project, we investigated the self-assembly of a virus with and without its genome. A coarse-grained model was proposed for the viral subunit proteins and its genome (ssDNA). Langevin dynamics simulation, and replica exchange method were used to determine the kinetics and energetics of the self-assembly process, respectively. The self-assembly follows a nucleation-growth kind of mechanism. The ssDNA plays a crucial role in the self-assembly by acting as a template and enhancing the local concentration of the subunits. The presence of the genome does not changes the mechanism of the self-assembly but it reduces the nucleation time and enhances the growth rate by almost an order of magnitude. The second part of the project involves the investigation of the dynamics of the ejection of dsDNA from phages. A coarse-grained model was used for the phage and dsDNA. Langevin dynamics simulation was used to investigate the kinetics of the ejection. The ejection is a stochastic process and a slow intermediate rate kinetics was observed for most ejection trajectories. We discovered that the jamming of the DNA at the pore mouth at high packing fraction and for a disordered system is the reason for the intermediate slow kinetics. The third part of the project involves translocation of ssDNA through MspA protein pore. MspA protein pore has the potential for genome sequencing because of its ability to clearly distinguish the four different nucleotides based on their blockade current, but it is a challenge to use this pore for any practical application because of the very fast traslocation time. We resolved the state of DNA translocation reported in the recent experimental work . We also investigated two methods for slowing down the translocation process: pore mutation and use of alternating voltage. Langevin dynamics simulation and Poisson Nernst Planck solver were used for the investigation. We demonstrated that mutation of the protein pore or applying alternating voltage is not a perfect solution for increasing translocation time deterministically. Both strategies resulted in enhanced average translocation time as well as the width of the translocation time distribution. The increase in the width of the translocation time distribution is undesired. In the last part of the project, we investigated the applicability of the polyelectrolyte theory in the computer simulation of polyelectrolyte translocation through nanopores. We determined that the Debye Huckel approximation is acceptable for most translocation simulations as long as the coarse grained polymer bead size is comparable or larger than the Debye length. We also determined that the equilibrium translocation theory is applicable to the polyelectrolyte translocation through a nanopore under biasing condition. The unbiased translocation behavior of a polyelectrolyte chain is qualitatively different from the Rouse model predictions, except for the case where the polyelectrolyte is very small compared to the nanopore.

Mahalik, Jyoti Prakash

266

The effects of gopher tortoise (Gopherus polyphemus) translocation on movements, reproductive activity, and body condition of resident and translocated individuals in Central Florida  

Microsoft Academic Search

Human-caused destruction of xeric habitats in Florida that support gopher tortoises (Gopherus polyphemus Daudin) is occurring at a rapid rate. One conservation strategy that has been used for numerous taxa is translocation. The effects of translocation on the health, reproductive activity, and movements of translocated and resident telemetered individuals was evaluated for a population of gopher tortoises in central-Florida from

Susannah Christina Riedl

2006-01-01

267

Integrable Background Geometries  

NASA Astrophysics Data System (ADS)

This work has its origins in an attempt to describe systematically the integrable geometries and gauge theories in dimensions one to four related to twistor theory. In each such dimension, there is a nondegenerate integrable geometric structure, governed by a nonlinear integrable differential equation, and each solution of this equation determines a background geometry on which, for any Lie group G, an integrable gauge theory is defined. In four dimensions, the geometry is selfdual conformal geometry and the gauge theory is selfdual Yang-Mills theory, while the lower-dimensional structures are nondegenerate (i.e., non-null) reductions of this. Any solution of the gauge theory on a k-dimensional geometry, such that the gauge group H acts transitively on an ?-manifold, determines a (k+?)-dimensional geometry (k+??4) fibering over the k-dimensional geometry with H as a structure group. In the case of an ?-dimensional group H acting on itself by the regular representation, all (k+?)-dimensional geometries with symmetry group H are locally obtained in this way. This framework unifies and extends known results about dimensional reductions of selfdual conformal geometry and the selfdual Yang-Mills equation, and provides a rich supply of constructive methods. In one dimension, generalized Nahm equations provide a uniform description of four pole isomonodromic deformation problems, and may be related to the {SU}(?) Toda and dKP equations via a hodograph transformation. In two dimensions, the {Diff}(S^1) Hitchin equation is shown to be equivalent to the hyperCR Einstein-Weyl equation, while the {SDiff}(?^2) Hitchin equation leads to a Euclidean analogue of Plebanski's heavenly equations. In three and four dimensions, the constructions of this paper help to organize the huge range of examples of Einstein-Weyl and selfdual spaces in the literature, as well as providing some new ! ones. The nondegenerate reductions have a long ancestry. More ! recently , degenerate or null reductions have attracted increased interest. Two of these reductions and their gauge theories (arguably, the two most significant) are also described.

Calderbank, David M. J.

2014-03-01

268

Understanding Publication Bias in Reintroduction Biology by Assessing Translocations of New Zealand's Herpetofauna.  

PubMed

The intentional translocation of animals is an important tool for species conservation and ecosystem restoration, but reported success rates are low, particularly for threatened and endangered species. Publication bias further distorts success rates because the results of successful translocations may be more likely to be published than failed translocations. We conducted the first comprehensive review of all published and unpublished translocations of herpetofauna in New Zealand to assess publication bias. Of 74 translocations of 29 species in 25 years, 35 have been reported in the published literature, and the outcomes of 12 have been published. Using a traditional definition of success, publication bias resulted in a gross overestimate of translocation success rates (41.7% and 8.1% for published and all translocations, respectively), but bias against failed translocations was minimal (8.3% and 6.8%, respectively). Publication bias against translocations with uncertain outcomes, the vast majority of projects, was also strong (50.0% and 85.1% for published and all translocations, respectively). Recent translocations were less likely to be published than older translocations. The reasons behind translocations were related to publication. A greater percentage of translocations for conservation and research were published (63.3% and 40.0%, respectively) than translocations for mitigation during land development (10.0%). Translocations conducted in collaboration with a university were more frequently published (82.7% and 24.4%, respectively). To account for some of this publication bias, we reassessed the outcome of each translocation using a standardized definition of success, which takes into consideration the species' life history and the time since release. Our standardized definition of translocation success provided a more accurate summary of success rates and allows for a more rigorous evaluation of the causes of translocation success and failure in large-scale reviews. Entendiendo el Sesgo de Publicaciones en la Biología de la Reintroducción Mediante el Estudio de Traslocaciones de la Herpetofauna de Nueva Zelanda. PMID:24606604

Miller, Kimberly A; Bell, Trent P; Germano, Jennifer M

2014-08-01

269

Incipient Genome Differentiation in Gossypium. III. Comparison of Chromosomes of G. HIRSUTUM and Asiatic Diploids Using Heterozygous Translocations  

PubMed Central

Hybrids between upland cotton (G. hirsutum, genome constitution 2AhDh) and either A-genome or D-genome diploid species exhibit 26 paired and 13 unpaired chromosomes at metaphase I. The Ah and Dh genomes are therefore considered homoeologous with those of the respective diploids. Previous studies, nevertheless, revealed a low level of ("incipient") differentiation between Dh and various diploid D genomes. The diploid A genomes have been regarded as more closely homologous to Ah on the basis of low preferential pairing and autotetraploid segregation ratios in allohexaploids.—The present study addressed the following questions: Are the diploid A genomes differentiated from Ah in meiotic homology? If so, is the differentiation manifested equally by all 13 chromosomes or is it localized in certain chromosomes?—Three diploid A-genome lines representing G. herbaceum and G. arboreum were hybridized by in ovulo culture of embryos (1) with a standard line of G. hirsutum, which differs from G. herbaceum by two and from G. arboreum by three naturally occurring reciprocal translocations involving chromosomes 1–5, and (2) with six lines homozygous for experimental translocations involving chromosomes 6, 7, 10, 11, 12 and 13. Chiasma frequencies in hybrids were compared with those in appropriate G. hirsutum controls. In every comparison overall chiasma frequencies were slightly lower in the hybrids. Therefore Ah appears to be differentiated from the diploid A genomes. No localized differentiation was detected in chromosomes marked by experimental translocations. The differentiation may be localized mainly in chromosomes 4 and 5.

Menzel, Margaret Y.; Hasenkampf, Clare A.; Stewart, James McD.

1982-01-01

270

Myc translocations in B cell and plasma cell neoplasms.  

PubMed

Chromosomal translocations that join the cellular oncogene Myc (c-myc) with immunoglobulin (Ig) heavy-chain (Igh) or light-chain (Igk, Igl) loci are widely believed to be the crucial initiating oncogenic events in the development of B cell and plasma cell neoplasms in three mammalian species: Burkitt lymphoma (BL) in human beings, plasmacytoma (PCT) in mice, and immunocytoma in rats. Among the Myc-Ig translocations found in these neoplasms, mouse PCT T(12;15)(Igh-Myc) is of special interest because it affords a uniquely useful model system to study the fundamental outstanding questions on the mechanisms, genetics, and biological consequences of Myc translocations. Mouse T(12;15) is the direct counterpart of the human BL t(8;14)(q24;q32) translocation and thus of great relevance for human cancer. Mouse T(12;15) is the only cancer-associated translocation in mice that occurs with high incidence, spontaneity, and cell-type specificity. Due to the development of PCR methods for the detection of the underlying reciprocal Myc-Igh junction fragments, it is now known that mouse T(12;15) can be a dynamic process that begins with the genetic exchange of Myc and the Igh switch mu region (Smu), progresses by class switch recombination (CSR) just 3' of the translocation break site, and then undergoes further clonal diversification by micro-deletions in the junction flanks. The molecular pathway that subverts CSR to mediate trans-chromosomal joining of Myc and Smu (translocation origin) and secondary modification of Myc-Igh junctions (translocation "remodeling") has not been elucidated, but recent evidence indicates that it includes CSR factors, such as the activation-induced cytidine deaminase (AID), that may also be involved in the ongoing neoplastic progression of the translocation-bearing tumor precursor. Transgenic mouse models of T(12;15)/t(8;14), including newly developed "iMyc" gene-insertion mice, will be useful in elucidating the role of these CSR factors in the progression of Myc-induced B cell tumors. PMID:16815105

Janz, Siegfried

2006-09-01

271

[ISPpy1, a novel mobile element of the ancient Psychrobacter maritimus permafrost strain: translocations in Escherichia coli K-12 cells and formation of composite transposons].  

PubMed

It was shown that IS element ISPpyl isolated earlier in the permafrost strain Psychrobacter maritimus MR29-12 has a high level of functional activity in cells of the heterologous host Escherichia coli K-12. ISPpyl can be translocated in E. coli cells by itself and mobilize adjacent genes and can also form composite transposons flanked by two copies of this element. Apart from translocations between different plasmids, the composite ISPpyl-containing transposon Tn5080a is capable of translocation from the plasmid into the E. coli chromosome with high frequency and from the chromosome into the plasmid. Among products of Tn5080a transposition into plasmid R388, simple insertions were predominantly formed together with cointegrates. Upon mobilization of adjacent genes with the use of one ISPpyl copy, only cointegrates arise. PMID:22679779

Petrova, M A; Gorlenko, Zh M; Scherbatova, N A; Mindlin, S Z

2012-03-01

272

Two translocations of chromosome 15q associated with dyslexia  

PubMed Central

Developmental dyslexia is characterised by difficulties in learning to read. As reading is a complex cognitive process, multiple genes are expected to contribute to the pathogenesis of dyslexia. The genetics of dyslexia has been a target of molecular studies during recent years, but so far no genes have been identified. However, a locus for dyslexia on chromosome 15q21 (DYX1) has been established in previous linkage studies. We have identified two families with balanced translocations involving the 15q21-q22 region. In one family, the translocation segregates with specific dyslexia in three family members. In the other family, the translocation is associated with dyslexia in one family member. We have performed fluorescence in situ hybridisation (FISH) studies to refine the position of the putative dyslexia locus further. Our results indicate that both translocation breakpoints on 15q map within an interval of approximately 6-8 Mb between markers D15S143 and D15S1029, further supporting the presence of a locus for specific dyslexia on 15q21.???Keywords: dyslexia; reading disability; chromosome 15; translocation

Nopola-Hemmi, J.; Taipale, M.; Haltia, T.; Lehesjoki, A.; Voutilainen, A.; Kere, J.

2000-01-01

273

A somatic origin of homologous Robertsonian translocations and isochromosomes  

SciTech Connect

One t(14q 14q), three t(15q 15q), two t(21q21q), and two t(22q22q) nonmosaic, apparently balanced, de novo Robertsonian translocation cases were investigated with polymorphic markers to establish the origin of the translocated chromosomes. Four cases had results indicative of an isochromosome: one t(14q14q) case with mild mental retardation and maternal uniparental disomy (UPD) for chromosome 14, one t(15q15q) case with the Prader-Willi syndrome and UPD(15), a phenotypically normal carrier of t(22q22q) with maternal UPD(22), and a phenotypically normal t(21q21q) case of paternal UPD(21). All UPD cases showed complete homozygosity throughout the involved chromosome, which is supportive of a postmeiotic origin. In the remaining four cases, maternal and paternal inheritance of the involved chromosome was found, which unambiguously implies a somatic origin. One t(15q15q) female had a child with a ring chromosome 15, which was also of probable postmeiotic origin as recombination between grandparental haplotypes had occurred prior to ring formation. UPD might be expected to result from de novo Robertsonian translocations of meiotic origin; however, all de novo homologous translocation cases, so far reported, with UPD of chromosomes 14, 15, 21, or 22 have been isochromosomes. These data provide the first direct evidence that nonmosaic Robertsonian translocations, as well as isochromosomes, are commonly the result of a mitotic exchange. 75 refs., 1 fig., 4 tabs.

Robinson, W.P.; Bernasconi, F.; Schinzel, A.A. (Univ. of Zurich (Switzerland)); Basaran, S.; Yueksel-Apak, M. (Univ. of Istanbul (Turkey)); Neri, G. (Universita Cattolica, Rome (Italy)); Serville, F. (Hopital d'Enfants Pellegrin, Bordeaux (France)); Balicek, P.; Haluza, R. (Univ. Hospital of Hradeck Kralove, Hradec Kralove (Czech Republic)); Farah, L.M.S. (Escuola Paulista de Medicina, Sao Paulo (Brazil)) (and others)

1994-02-01

274

Stiff Filamentous Virus Translocations through Solid-State Nanopores  

NASA Astrophysics Data System (ADS)

We present experimental results of filamentous virus translocations through a solid-state nanopore. A nanopore can easily detect fd virus due to its linear shape and high linear charge density. With a width of 6.6 nm, a monodisperse length of 880 nm, and a long persistence length of 2.2,m, fd is a model stiff polymer for testing theories of translocation dynamics. The distribution of measured ionic current blockade amplitudes indicates that fd virus does not fold during translocation. The mean fd translocation time was linearly proportional to the applied voltage in the range 75 mV to 500 mV. The dispersion in translocation times was much greater for fd virus than expected from Brownian motion or the conformation-dependent fluid drag. Possible explanations for the observed dispersion will be discussed in light of its dependence on voltage and the salt concentration. This work was supported by NSF Grant CBET0846505 and the Brown University IMNI.

McMullen, Angus; Stein, Derek; Tang, Jay

2013-03-01

275

Botulinum Neurotoxin Devoid of Receptor Binding Domain Translocates Active Protease  

PubMed Central

Clostridium botulinum neurotoxin (BoNT) causes flaccid paralysis by disabling synaptic exocytosis. Intoxication requires the tri-modular protein to undergo conformational changes in response to pH and redox gradients across endosomes, leading to the formation of a protein-conducting channel. The ?50 kDa light chain (LC) protease is translocated into the cytosol by the ?100 kDa heavy chain (HC), which consists of two modules: the N-terminal translocation domain (TD) and the C-terminal Receptor Binding Domain (RBD). Here we exploited the BoNT modular design to identify the minimal requirements for channel activity and LC translocation in neurons. Using the combined detection of substrate proteolysis and single-channel currents, we showed that a di-modular protein consisting only of LC and TD was sufficient to translocate active protease into the cytosol of target cells. The RBD is dispensable for cell entry, channel activity, or LC translocation; however, it determined a pH threshold for channel formation. These findings indicate that, in addition to its individual functions, each module acts as a chaperone for the others, working in concert to achieve productive intoxication.

Fischer, Audrey; Mushrush, Darren J.; Lacy, D. Borden; Montal, Mauricio

2008-01-01

276

Strandwise translocation of a DNA glycosylase on undamaged DNA.  

PubMed

Base excision repair of genotoxic nucleobase lesions in the genome is critically dependent upon the ability of DNA glycosylases to locate rare sites of damage embedded in a vast excess of undamaged DNA, using only thermal energy to fuel the search process. Considerable interest surrounds the question of how DNA glycosylases translocate efficiently along DNA while maintaining their vigilance for target damaged sites. Here, we report the observation of strandwise translocation of 8-oxoguanine DNA glycosylase, MutM, along undamaged DNA. In these complexes, the protein is observed to translocate by one nucleotide on one strand while remaining untranslocated on the complementary strand. We further report that alterations of single base-pairs or a single amino acid substitution (R112A) can induce strandwise translocation. Molecular dynamics simulations confirm that MutM can translocate along DNA in a strandwise fashion. These observations reveal a previously unobserved mode of movement for a DNA-binding protein along the surface of DNA. PMID:22219368

Qi, Yan; Nam, Kwangho; Spong, Marie C; Banerjee, Anirban; Sung, Rou-Jia; Zhang, Michael; Karplus, Martin; Verdine, Gregory L

2012-01-24

277

Enzyme-modulated DNA translocation through a nanopore.  

PubMed

We present a Langevin dynamics simulation study of enzyme-modulated translocation of a single-stranded DNA molecule through a cylindrical nanopore. The toroidal-shaped enzyme placed along the axis of the pore, threads a DNA molecule at a constant rate. As a result of this controlled release process, the length of DNA available for translocation varies with time. We examine the effect of time-dependent conformational entropy of the DNA on the translocation process. In addition, we also examine the effects of both the separation between the exonuclease and the pore, and the rate at which DNA is released by the enzyme. Our results indicate that the separation distance primarily influences the entry of the DNA into the pore. The length of the DNA released by the exonuclease that is most likely to enter the pore is nearly equal to separation distance between the pore and the exonuclease despite the flexibility of the polymer. However, the speed at which the DNA translocates through the nanopore is solely determined by the rate at which the exonuclease releases the DNA. We find that the translocation velocity is directly proportional to the rate of release. PMID:19958025

Panwar, Ajay S; Muthukumar, M

2009-12-30

278

Twin-Arginine Translocation Pathway in Streptomyces lividans  

PubMed Central

The recently discovered bacterial twin-arginine translocation (Tat) pathway was investigated in Streptomyces lividans, a gram-positive organism with a high secretion capacity. The presence of one tatC and two hcf106 homologs in the S. lividans genome together with the several precursor proteins with a twin-arginine motif in their signal peptide suggested the presence of the twin-arginine translocation pathway in the S. lividans secretome. To demonstrate its functionality, a tatC deletion mutant was constructed. This mutation impaired the translocation of the Streptomyces antibioticus tyrosinase, a protein that forms a complex with its transactivator protein before export. Also the chimeric construct pre-TorA-23K, known to be exclusively secreted via the Tat pathway in Escherichia coli, could be translocated in wild-type S. lividans but not in the tatC mutant. In contrast, the secretion of the Sec-dependent S. lividans subtilisin inhibitor was not affected. This study therefore demonstrates that also in general in Streptomyces spp. the Tat pathway is functional. Moreover, this Tat pathway can translocate folded proteins, and the E. coli TorA signal peptide can direct Tat-dependent transport in S. lividans.

Schaerlaekens, Kristien; Schierova, Michaela; Lammertyn, Elke; Geukens, Nick; Anne, Jozef; Van Mellaert, Lieve

2001-01-01

279

Detection of Kinase Translocation Using Microfluidic Electroporative Flow Cytometry  

PubMed Central

Directed localization of kinases within cells is important for their activation and involvement in signal transduction. Detection of these events has been largely carried out based on imaging of a low number of cells and subcellular fractionation/Western blotting. These conventional techniques either lack the high throughput desired for probing an entire cell population or provide only the average behaviors of cell populations without information from single cells. Here we demonstrate a new tool, referred to as microfluidic electroporative flow cytometry, to detect the translocation of an EGFP-tagged tyrosine kinase, Syk, to the plasma membrane in B cells at the level of the cell population. We combine electroporation with flow cytometry and observe the release of intracellular kinase out of the cells during electroporation. We found that the release of the kinase was strongly influenced by its subcellular localization. Cells stimulated through the antigen receptor have a fraction of the kinase at the plasma membrane and retain more kinase after electroporation than do cells without stimulation and translocation. We are able to differentiate a cell population with translocation from one without it with the information collected from individual cells of the entire population. This technique potentially allows detection of protein translocation at the single cell level. Due to the frequent involvement of kinase translocations in disease processes such as oncogenesis, our approach will have utility for kinase-related drug discovery and tumor diagnosis and staging.

Wang, Jun; Bao, Ning; Paris, Leela L.; Wang, Hsiang-Yu; Geahlen, Robert L.; Lu, Chang

2009-01-01

280

Background Lamb waves in the Earth's atmosphere  

NASA Astrophysics Data System (ADS)

Lamb waves of the Earth's atmosphere in the millihertz band have been considered as transient phenomena excited only by large events [e.g. the major volcanic eruption of Krakatoa in 1833, the impact of Siberian meteorite in 1908, the testing of large nuclear tests and the huge earthquakes, Garrett1969]. In a case of the solid Earth, observation of background free oscillations in the millihertz band-now known as Earth's background free oscillations or seismic hum, has been firmly established. Above 5 mHz, their dominant excitation sources are oceanic infragravity waves. At 3.7 and 4.4 mHz an elasto-acoustic resonance between the solid Earth and the atmosphere was observed [Nishida et al., 2000]. These seismic observations show that the contribution of atmospheric disturbances to the seismic hum is dominant below 5 mHz. Such contribution implies background excitations of acoustic-gravity waves in this frequency range. For direct detection of the background acoustic-gravity waves, our group conducted observations using an array of barometers [Nishida et al. 2005]. However, the spatial scale of the array of about 10 km was too small to detect acoustic modes below 10 mHz. Since then, no direct observations of these waves have been reported. In 2011, 337 high-resolution microbarometers were installed on a continental scale at USArray Transportable Array. The large and dense array enables us to detect the background atmospheric waves. Here, we show the first evidence of background Lamb waves in the Earth's atmosphere from 0.2 to 10 mHz, based on the array analysis of microbarometer data from the USArray in 2012. The observations suggest that the excitation sources are atmospheric disturbances in the troposphere. Theoretically, their energy in the troposphere tunnels into the thermosphere at a resonant frequency via thermospheric gravity wave, where the observed amplitudes indeed take a local minimum. The energy leak through the frequency window could partly contribute to thermospheric wave activity. Tropospheric disturbances exciting background Lamb waves may also be responsible for seismic hum at frequencies below 5 mHz.

Nishida, K.; Kobayashi, N.; Fukao, Y.

2013-12-01

281

Recovery of a marked translocation strain that will facilitate the isolation of balancer chromosomes in the Mediterranean fruit fly, Ceratitis capitata.  

PubMed

The results of two screens for mutations and chromosomal aberrations in Ceratitis capitata are presented. Three dominant mutations were recovered, including Sb, which is associated with a homozygous lethal translocation between the third and fifth chromosomes, T(3;5)Sb, with the fifth chromosome breakpoint adjacent to y. The T(3;5)Sb chromosome is maintained by selecting for Sb in a T(3;5)Sb, w2 Sb y2 wp/w2 y2 wp stock and can be used to distinguish between other chromosomes carrying differential combinations of the recessive markers w2 y2 wp. The ability to isolate particular marked chromosomes is essential in order to recover an inversion-based balancer chromosome. In addition to the recovery of dominant mutations, gamma-ray induced somatic mosaics of w2 and y2 and zygotic w mosaics were found. The generation of zygotic mosaics following mutagenesis can give mutants with a mosaic germ line that fail to breed true in the first generation. A screen of 22,830 irradiated chromosomes failed to recover variegating alleles of w, although such alleles might be recovered in a larger screen. The high frequency of dominant mutations and the instability at the w locus in our stocks implies a background level of dysgenic activity. These results have implications for the construction and long-term maintenance of genetically modified strains. PMID:9644834

Gubb, D; Zacharopoulou, A; Livadaras, Y; Gourzi, P; Roote, J; Savakis, C

1998-04-01

282

Matrix-driven translocation of cells and nonliving particles.  

PubMed

Cells of metazoan organisms produce and react to complex macromolecular microenvironments known as extracellular matrices. Assembly in vitro of native, compositionally nonuniform collagen-fibronectin matrices caused translocation of certain types of cells or polystyrene-latex beads from regions lacking fibronectin into regions containing it. The translocation process was not due to diffusion, convection, or electrostatic distribution effects, but may depend on nonequilibrium phenomena at the interface of contiguous collagen matrices formed in the presence and absence of fibronectin or particles. Extracellular matrix formation alone was sufficient to drive translocation by a biophysical process that may play a role in cellular migration during embryogenesis, as well as in other types of tissue reorganization such as inflammation, wound healing, and tumor invasion. PMID:4001925

Newman, S A; Frenz, D A; Tomasek, J J; Rabuzzi, D D

1985-05-17

283

Insights into Buforin II Membrane Translocation from Molecular Dynamics Simulations  

PubMed Central

Buforin II is a histone-derived antimicrobial peptide that readily translocates across lipid membranes without causing significant membrane permeabilization. Previous studies showed that mutating the sole proline of buforin II dramatically decreases its translocation. As well, researchers have proposed that the peptide crosses membranes in a cooperative manner through forming transient toroidal pores. This paper reports molecular dynamics simulations designed to investigate the structure of buforin II upon membrane entry and evaluate whether the peptide is able to form toroidal pore structures. These simulations showed a relationship between protein-lipid interactions and increased structural deformations of the buforin N-terminal region promoted by proline. Moreover, simulations with multiple peptides show how buforin II can embed deeply into membranes and potentially form toroidal pores. Together, these simulations provide structural insight into the translocation process for buforin II in addition to providing more general insight into the role proline can play in antimicrobial peptides.

Elmore, Donald E.

2012-01-01

284

Nanocolonies and diagnostics of oncological diseases associated with chromosomal translocations.  

PubMed

This paper reviews chromosomal abnormalities observed in oncological diseases, the history of discovery of chromosomal translocations (a widespread type of chromosomal abnormalities), and statistical data showing a correlation between translocations and emergence of oncological diseases (in particular leukemia). The importance of detection of minimal residual disease (MRD) in treatment of leukemia associated with translocations is discussed along with methods of MRD diagnosis, followed by description of a novel diagnostic procedure for the detection of single chimeric mRNA molecules serving as MRD markers. This procedure includes a number of improvements, of which the most important is the use of a PCR version of the method of nanocolonies (other names are molecular colonies, polonies) that provides for the determination of the absolute titer of RNA tumor markers, excludes false positive results in the detection of chimeric molecules, and significantly exceeds other methods in the sensitivity of MRD detection. PMID:21418000

Chetverina, E V; Chetverin, A B

2010-12-01

285

Crystallographic snapshot of cellulose synthesis and membrane translocation  

PubMed Central

Cellulose, the most abundant biological macromolecule, is an extracellular, linear polymer of glucose molecules. It represents an essential component of plant cell walls but is also found in algae and bacteria. In bacteria, cellulose production frequently correlates with the formation of biofilms, a sessile, multicellular growth form. Cellulose synthesis and transport across the inner bacterial membrane is mediated by a complex of the multi-spanning catalytic BcsA subunit and the membrane-anchored, periplasmic BcsB protein. Here we present the crystal structure of a complex of BcsA and BcsB from Rhodobacter sphaeroides containing a translocating polysaccharide. The structure of the BcsA-B translocation intermediate reveals the architecture of the cellulose synthase, demonstrates how BcsA forms a cellulose-conducting channel, and suggests a model for the coupling of cellulose synthesis and translocation in which the nascent polysaccharide is extended by one glucose molecule at a time.

Morgan, Jacob L.W.; Strumillo, Joanna; Zimmer, Jochen

2012-01-01

286

Probing nanoparticle translocation across the permeable endothelium in experimental atherosclerosis  

PubMed Central

Therapeutic and diagnostic nanomaterials are being intensely studied for several diseases, including cancer and atherosclerosis. However, the exact mechanism by which nanomedicines accumulate at targeted sites remains a topic of investigation, especially in the context of atherosclerotic disease. Models to accurately predict transvascular permeation of nanomedicines are needed to aid in design optimization. Here we show that an endothelialized microchip with controllable permeability can be used to probe nanoparticle translocation across an endothelial cell layer. To validate our in vitro model, we studied nanoparticle translocation in an in vivo rabbit model of atherosclerosis using a variety of preclinical and clinical imaging methods. Our results reveal that the translocation of lipid–polymer hybrid nanoparticles across the atherosclerotic endothelium is dependent on microvascular permeability. These results were mimicked with our microfluidic chip, demonstrating the potential utility of the model system.

Kim, YongTae; Lobatto, Mark E.; Kawahara, Tomohiro; Lee Chung, Bomy; Mieszawska, Aneta J.; Sanchez-Gaytan, Brenda L.; Fay, Francois; Senders, Max L.; Calcagno, Claudia; Becraft, Jacob; Tun Saung, May; Gordon, Ronald E.; Stroes, Erik S. G.; Ma, Mingming; Farokhzad, Omid C.; Fayad, Zahi A.; Mulder, Willem J. M.; Langer, Robert

2014-01-01

287

Translocation of a forced polymer chain through a crowded channel  

NASA Astrophysics Data System (ADS)

We construct a coarse-grained model in terms of the multiple particles collision (MPC) method to study the translocation dynamics of a linear polymer through a crowded channel full of fixed obstacles. The influences of a crowded environment are focused on. We explore the power-law dependence of the polymer mobility coefficient on its length and on the crowded environment. It is shown that the crowded environment may benefit the length-dependent separation of polymer chains. The exponents characterizing the power-law behavior are discussed to distinguish different dynamical regimes. The properties of the translocating polymer, such as trajectory, moving configuration, and radius of gyration, are investigated. The influences of the radius of obstacles and hydrodynamics interaction on the translocating process are also studied. We believe our studies can shed light on the understanding of complex transport processes in many biological systems.

Chen, Jiang-Xing; Zhu, Jin-Xing; Ma, Yu-Qiang; Cao, Jian-Shu

2014-04-01

288

Chromosomal Translocation and Segmental Duplication in Cryptococcus neoformans†  

PubMed Central

Large chromosomal events such as translocations and segmental duplications enable rapid adaptation to new environments. Here we marshal genomic, genetic, meiotic mapping, and physical evidence to demonstrate that a chromosomal translocation and segmental duplication occurred during construction of a congenic strain pair in the fungal human pathogen Cryptococcus neoformans. Two chromosomes underwent telomere-telomere fusion, generating a dicentric chromosome that broke to produce a chromosomal translocation, forming two novel chromosomes sharing a large segmental duplication. The duplication spans 62,872 identical nucleotides and generated a second copy of 22 predicted genes, and we hypothesize that this event may have occurred during meiosis. Gene disruption studies of one embedded gene (SMG1) corroborate that this region is duplicated in an otherwise haploid genome. These findings resolve a genome project assembly anomaly and illustrate an example of rapid genome evolution in a fungal genome rich in repetitive elements.

Fraser, James A.; Huang, Johnny C.; Pukkila-Worley, Read; Alspaugh, J. Andrew; Mitchell, Thomas G.; Heitman, Joseph

2005-01-01

289

Prenatal diagnosis of an autosomal translocation with regular trisomy 21.  

PubMed

The coincidence of trisomy 21 and a structural rearrangement is very rare, and even it has not been reported as a prenatal diagnosis yet. In this article, we present an autosomal translocation carrier fetus with trisomy 21: 47,XX,+21, t(3;8)(p21;q24). Although the coincidence of reciprocal translocation and trisomy may be seen in reciprocal translocation carrier families, de novo cases are extremely rare. The presented case is diagnosed by amniocentesis, which was performed because of abnormal fetal ultrasonographic findings and increased trisomy 21 risk at maternal serum screening test. The postmortem pathologic examination of the fetus revealed that the findings of hypertelorism and right lung with two lobes are interesting novel findings of our cases associated with the breakpoints 3p21 and 8q24. PMID:23301917

Tunca, Yusuf; Deveci, M Salih; Koc, Altug; Kaya, Halide; Alanbay, Ibrahim; Coksuer, Hakan; Dede, Murat

2013-06-01

290

Infrared Target/Background Discrimination - Background Spectral Modeling.  

National Technical Information Service (NTIS)

This report discusses the development of statistical models for signals in the background radiance distribution. Techniques for analyzing multispectral line scan data are developed and demonstrated on background data obtained by the Environmental Research...

L. J. Pinson P. M. Goggans

1978-01-01

291

A balanced translocation truncates Neurotrimin in a family with intracranial and thoracic aortic aneurysm  

PubMed Central

Background Balanced chromosomal rearrangements occasionally have strong phenotypic effects, which may be useful in understanding pathobiology. However, conventional strategies for characterizing breakpoints are laborious and inaccurate. We present here a proband with a thoracic aortic aneurysm and a balanced translocation t(10;11)(q23.2;q24.2). Our purpose was to sequence the chromosomal breaks in this family to reveal a novel candidate gene for aneurysm. Methods and results Intracranial and thoracic aortic aneurysms appear to run in the family in an autosomal dominant manner: After exploring the family history, we observed that the proband’s two siblings both died from cerebral hemorrhage, and the proband’s parent and parent’s sibling died from aortic rupture. After application of a genome-wide paired-end DNA sequencing method for breakpoint mapping, we demonstrate that this translocation breaks intron 1 of a splicing isoform of Neurotrimin (NTM) at 11q25 in a previously implicated candidate region for intracranial (IAs) and aortic aneurysms (AAs) (OMIM 612161). Conclusions Our results demonstrate the feasibility of genome-wide paired-end sequencing for the characterization of balanced rearrangements and identification of candidate genes in patients with potentially disease-associated chromosome rearrangements. The family samples were gathered as a part of our recently launched National Registry of Reciprocal Balanced Translocations and Inversions in Finland (n=2575), and we believe that such a registry will be a powerful resource for the localization of chromosomal aberrations, which can bring insight into the etiology of related phenotypes.

Luukkonen, Tiia; Poyhonen, Minna; Palotie, Aarno; Ellonen, Pekka; Lagstrom, Sonja; Lee, Joseph H; Terwilliger, Joseph D; Salonen, Riitta; Varilo, Teppo

2014-01-01

292

Bacterial DNA translocation holds increased insulin resistance and systemic inflammatory levels in morbid obese patients.  

PubMed

Background: Morbidly obese patients show several common comorbidities associated with immunological alterations such as a sustained low-level proinflammatory profile. Bacterial product translocation is frequent in inflammation-related diseases and may aggravate patients' clinical outcome. Design: Consecutively admitted morbidly obese patients who presented indications for bariatric surgery were studied. Before surgery, patients were subjected to a modified fasting diet. Patients underwent surgery by sleeve gastrectomy or laparoscopic Roux-en-Y gastric bypass. Clinical and analytical parameters were recorded. Blood samples were collected at baseline, at the end of a 3-month modified fasting period, and 3, 6, and 12 months after surgery. Serum cytokine and endotoxin levels were evaluated by flow cytometry and ELISA, respectively. Bacterial DNA was identified in blood by broad-range PCR of prokaryote 16SrRNA gene and partial sequencing analysis. Results: Fifty-eight patients were included in the study. All patients showed a significantly reduced weight and body mass index at each time-point. Postoperative mortality was null. Bacterial DNA translocation rate was 32.8% (19 of 58) at baseline; 13.8% (8 of 58) after the modified fasting period; and 13.8% (8 of 58), 1.8% (1 of 58), and 5.2% (3 of 58) at 3, 6, and 12 months after surgery. Proinflammatory cytokines, serum endotoxin levels, and insulin resistance remained increased in patients with bacterial DNA despite weight loss and were individually affected by the appearance/clearance of bacterial DNA in blood. Multivariate analyses revealed bacterial DNA as an independent significant factor, explaining the systemic cytokine response and the insulin resistance levels in the studied population. Conclusion: Bacterial DNA translocation holds increased insulin resistance and systemic inflammatory levels in morbidly obese patients despite significant weight loss. PMID:24735424

Ortiz, Sergio; Zapater, Pedro; Estrada, José Luis; Enriquez, Pablo; Rey, Monica; Abad, Angel; Such, José; Lluis, Félix; Francés, Rubén

2014-07-01

293

Changes in gut bacterial populations and their translocation into liver and ascites in alcoholic liver cirrhotics  

PubMed Central

Background The liver is the first line of defence against continuously occurring influx of microbial-derived products and bacteria from the gut. Intestinal bacteria have been implicated in the pathogenesis of alcoholic liver cirrhosis. Escape of intestinal bacteria into the ascites is involved in the pathogenesis of spontaneous bacterial peritonitis, which is a common complication of liver cirrhosis. The association between faecal bacterial populations and alcoholic liver cirrhosis has not been resolved. Methods Relative ratios of major commensal bacterial communities (Bacteroides spp., Bifidobacterium spp., Clostridium leptum group, Enterobactericaea and Lactobacillus spp.) were determined in faecal samples from post mortem examinations performed on 42 males, including cirrhotic alcoholics (n?=?13), non-cirrhotic alcoholics (n?=?15), non-alcoholic controls (n?=?14) and in 7 healthy male volunteers using real-time quantitative PCR (RT-qPCR). Translocation of bacteria into liver in the autopsy cases and into the ascites of 12 volunteers with liver cirrhosis was also studied with RT-qPCR. CD14 immunostaining was performed for the autopsy liver samples. Results Relative ratios of faecal bacteria in autopsy controls were comparable to those of healthy volunteers. Cirrhotics had in median 27 times more bacterial DNA of Enterobactericaea in faeces compared to the healthy volunteers (p?=?0.011). Enterobactericaea were also the most common bacteria translocated into cirrhotic liver, although there were no statistically significant differences between the study groups. Of the ascites samples from the volunteers with liver cirrhosis, 50% contained bacterial DNA from Enterobactericaea, Clostridium leptum group or Lactobacillus spp.. The total bacterial DNA in autopsy liver was associated with the percentage of CD14 expression (p?=?0.045). CD14 expression percentage in cirrhotics was significantly higher than in the autopsy controls (p?=?0.004). Conclusions Our results suggest that translocation of intestinal bacteria into liver may be involved as a one factor in the pathogenesis of alcoholic liver cirrhosis.

2014-01-01

294

Gate effects on DNA translocation through silicon dioxide nanopore  

NASA Astrophysics Data System (ADS)

The effects of gate voltage on the translocation of DNA molecules through a nanopore are studied. A twenty-fold increase in the translocation time is observed with a positive gate voltage applied, without changing too much of the ionic current. The amplitude of the current blockage by the DNA molecules was reduced by roughly the same factor. At the same time, the number of the blocking events decreases significantly. The applied gate voltage also modulates the scatter plot of the amplitude of the current blockage against the dwell time. The observations are consistent with the recent theoretical results.

Yen, Pei-chun; Wang, Chung-hsuan; Hwang, Gwo-Jen; Chou, Y. C.

2012-03-01

295

Thoracic empyema due to bacterial translocation in acute appendicitis.  

PubMed

Appendicitis and thoracic empyema are rarely presented together. Herein, we present a thoracic empyema due to bacterial translocation in a patient, after she underwent appendicectomy for nonperforated acute appendicitis. Postoperative third day, thoracic empyema was revealed clinically and radiologically. Tube thoracostomy and antibiotherapy were performed. Despite all these therapy, her symptoms went on, and abdominal ultrasonography revealed multilocular collections and formations of abscess in the abdomen. All abscesses were drained by nonvascular interventional radiologic methods. We believe that simultaneous occurence of thoracic empyema and formations of abscess were occured due to bacterial translocation. PMID:23581268

Tokat, Arif Osman; Karasu, Sezgin; Barlas, Aziz Mutlu; Akgün, Yusuf Akif

2013-01-01

296

Free energy evaluation in polymer translocation via Jarzynski equality  

NASA Astrophysics Data System (ADS)

We perform, with the help of cloud computing resources, extensive Langevin simulations, which provide free energy estimates for unbiased three-dimensional polymer translocation. We employ the Jarzynski equality in its rigorous setting, to compute the variation of the free energy in single monomer translocation events. In our three-dimensional Langevin simulations, the excluded-volume and van der Waals interactions between beads (monomers and membrane atoms) are modeled through a repulsive Lennard-Jones (LJ) potential and consecutive monomers are subject to the Finite-Extension Nonlinear Elastic (FENE) potential. Analysing data for polymers with different lengths, the free energy profile is noted to have interesting finite-size scaling properties.

Mondaini, Felipe; Moriconi, L.

2014-05-01

297

Construction and Uses of New Compound B-A-A Maize Chromosome Translocations  

PubMed Central

Maize B-A translocations result from reciprocal interchanges between a supernumerary B chromosome and an arm of an essential A chromosome. Because of the frequent nondisjunction of the B centromere at the second pollen mitosis, B-A translocations have been used to locate genes to chromosome arms and to study the dosage effects of specific A segments. Compound B-A translocations (B-A-A translocations) are created by bringing together a simple B-A translocation with an A-A translocation in which breakpoints in the A-A and B-A translocations are in the same arm. Recombination in the region of shared homology of these A chromosome segments creates a B-A-A translocation. Success in creating and testing for a new B-A-A translocation requires that the B-A translocation be proximal to the A-A translocation and that the A-A translocation be proximal to the tester locus. The breakpoints of most of the A-A translocations have been cytologically defined by earlier investigators. Previous investigators have produced 16 B-A-A translocations and one B-A-A-A translocation, which collectively define 35 A chromosome breakpoints. We have enlarged this group by creating 64 new B-A-A translocations. We present a summary of the total of 81 B-A-A translocations showing their distribution among the chromosome arms and the 163 cytologically defined chromosome segments delimited by them. We also illustrate the method of construction of these B-A-A stocks and their uses.

Sheridan, William F.; Auger, Donald L.

2006-01-01

298

Radar Background Signal Reduction Study.  

National Technical Information Service (NTIS)

This report summarizes a study whose objective was to identify materials and/or techniques to reduce radar background signals for ground plane radar cross section (RCS) ranges. Background signal reduction is essential for improving the accuracy of RCS mea...

E. F. Knott C. J. Ray M. S. West R. J. Wohlers

1980-01-01

299

Pregalactic Cosmic Gravitational Wave Background.  

National Technical Information Service (NTIS)

An outline is given that estimates the expected gravitational wave background, based on plausible pregalactic sources. Some cosmologically significant limits can be put on incoherent gravitational wave background arising from pregalactic cosmic evolution....

R. A. Matzner

1989-01-01

300

Infrared Background and Target Measurement.  

National Technical Information Service (NTIS)

This thesis describes measurements of IR background radiance. To provide background radiance values for the development of the AN/SAR - 8 (IRSTD) system, the radiance of clouds and buildings was measured using the AGA Thermovision 780. The measurement val...

A. Manolopoulos

1985-01-01

301

Mitotic Crossing over and Nondisjunction in Translocation Heterozygotes of Aspergillus  

PubMed Central

To analyze mitotic recombination in translocation heterozygotes of A. nidulans two sets of well-marked diploids were constructed, homo- or heterozygous for the reciprocal translocations T1(IL;VIIR) or T2(IL;VIIIR) and heterozygous for selective markers on IL. It was found that from all translocation heterozygotes some of the expected mitotic crossover types could be selected. Such crossovers are monosomic for one translocated segment and trisomic for the other and recovery depends on the relative viabilities of these unbalanced types. The obtained segregants show characteristically reduced growth rates and conidiation dependent on sizes and types of mono- and trisomic segments, and all spontaneously produce normal diploid sectors. Such secondary diploid types either arose in one step of compensating crossing over in the other involved arm, or—more conspicuously—in two steps of nondisjunction via a trisomic intermediate.—In both of the analyzed translocations the segments translocated to IL were extremely long, while those translocated from IL were relatively short. The break in I for T1(I;VII) was located distal to the main selective marker in IL, while that of T2(I;VIII) had been mapped proximal but closely linked to it. Therefore, as expected, the selected primary crossover from the two diploids with T2( I;VIII) in coupling or in repulsion to the selective marker, showed the same chromosomal imbalance and poor growth. These could however be distinguished visually because they spontaneously produced different trisomic intermediates in the next step, in accordance with the different arrangement of the aneuploid segments. On the other hand, from diploids heterozygous for T1( I;VII) mitotic crossovers could only be selected when the selective markers were in coupling with the translocation; these crossovers were relatively well-growing and produced frequent secondary segregants of the expected trisomic, 2n+VII, type. For both translocations it was impossible to recover the reciprocal crossover types (which would be trisomic for the distal segments of I and monosomic for most of groups VII or VIII) presumably because these were too inviable to form conidia.—In addition to the selected segregants of expected types a variety of unexpected ones were isolated. The conditions of selection used favour visual detection of aneuploid types, even if these produce only a few conidial heads and are not at a selective advantage. For T2(I;VIII) these "non-selected" unbalanced segregants were mainly "reciprocal" crossovers of the same phenotype and imbalance as the selected ones. For T1(I;VII) two quite different types were obtained, both possibly originating with loss of the small VII–I translocation chromosome. One was isolated when the selective marker in repulsion to T1(I;VII) was used and, without being homo- or hemizygous for the selective marker, it produced stable sectors homozygous for this marker. The other was obtained from both coupling and repulsion diploids and showed a near-diploid genotype; it produced practically only haploid stable sectors of the type expected from monosomics, 2n–1 for the short translocation chromosome.

Kafer, Etta

1976-01-01

302

Fast Lighting Independent Background Subtraction  

Microsoft Academic Search

This paper describes a simple method of fast background subtraction based upon disparity verification that is invariant to arbitrarily rapid run-time changes in illumination. Using two or more cameras, the method requires the off-line construction of disparity fields mapping the primary background images. At runtime, segmentation is performed by checking background image to each of the additional auxiliary color intensity

Yuri Ivanov; Aaron Bobick; John Liu

2000-01-01

303

Frequency Generating Source: Frequency Synthesizers.  

National Technical Information Service (NTIS)

A mode of fractional frequency harmonic generation obtained by the modulation of a square wave reference signal is considered. The produced spectrum exhibits a particular structure. The longer the fractional part of the frequency of the modulating wave is...

N. Yahyabey S. Hassani

1992-01-01

304

Tic62: a protein family from metabolism to protein translocation  

PubMed Central

Background The function and structure of protein translocons at the outer and inner envelope membrane of chloroplasts (Toc and Tic complexes, respectively) are a subject of intensive research. One of the proteins that have been ascribed to the Tic complex is Tic62. This protein was proposed as a redox sensor protein and may possibly act as a regulator during the translocation process. Tic62 is a bimodular protein that comprises an N-terminal module, responsible for binding to pyridine nucleotides, and a C-terminal module which serves as a docking site for ferredoxin-NAD(P)-oxido-reductase (FNR). This work focuses on evolutionary analysis of the Tic62-NAD(P)-related protein family, derived from the comparison of all available sequences, and discusses the structure of Tic62. Results Whereas the N-terminal module of Tic62 is highly conserved among all oxyphototrophs, the C-terminal region (FNR-binding module) is only found in vascular plants. Phylogenetic analyses classify four Tic62-NAD(P)-related protein subfamilies in land plants, closely related to members from cyanobacteria and green sulphur bacteria. Although most of the Tic62-NAD(P)-related eukaryotic proteins are localized in the chloroplast, one subgroup consists of proteins without a predicted transit peptide. The N-terminal module of Tic62 contains the structurally conserved Rossman fold and probably belongs to the extended family of short-chain dehydrogenases-reductases. Key residues involved in NADP-binding and residues that may attach the protein to the inner envelope membrane of chloroplasts or to the Tic complex are proposed. Conclusion The Tic62-NAD(P)-related proteins are of ancient origin since they are not only found in cyanobacteria but also in green sulphur bacteria. The FNR-binding module at the C-terminal region of the Tic62 proteins is probably a recent acquisition in vascular plants, with no sequence similarity to any other known motifs. The presence of the FNR-binding domain in vascular plants might be essential for the function of the protein as a Tic component and/or for its regulation.

Balsera, Monica; Stengel, Anna; Soll, Jurgen; Bolter, Bettina

2007-01-01

305

Translocation t(11;14) and survival of patients with light chain (AL) amyloidosis  

PubMed Central

Background Light chain amyloidosis is a rare plasma cell dyscrasia. Interphase fluorescence in situ hybridization (FISH) coupled to cytoplasmic staining of specific Ig (cIg-FISH) on bone marrow plasma cells has become well established in the initial evaluation of multiple myeloma, a related disorder. Little, however, is known about cytogenetic abnormalities in patients with light chain amyloidosis. Design and Methods We reviewed 56 patients with light chain amyloidosis who had cIg-FISH performed as part of their routine clinical testing using the standard screening panel employed in multiple myeloma at our institution. Results Seventy percent of patients had abnormal cIg-FISH, with the most common abnormalities being IgH translocations [48%] – including t(11;14) [39%], and t(14;16) [2%] – and del13/del13q [30%]. No t(4;14) or deletions of 17p (p53) were observed. Patients with t(11;14) had the lowest levels of clonal plasma cells, and those with del13 had the highest. The risk of death for patients harboring the t(11;14) translocation was 2.1 (CI 1.04–6.4), which on multivariate analysis was independent of therapy. Conclusions Although preliminary, our data would suggest that cIg-FISH testing is important in patients with light chain amyloidosis and that t(11;14) is an adverse prognostic factor in these patients.

Bryce, Alan H.; Ketterling, Rhett P.; Gertz, Morie A.; Lacy, Martha; Knudson, Ryan A.; Zeldenrust, Steven; Kumar, Shaji; Hayman, Suzanne; Buadi, Francis; Kyle, Robert A.; Greipp, Philip R.; Lust, John A.; Russell, Stephen; Rajkumar, S. Vincent; Fonseca, Rafael; Dispenzieri, Angela

2009-01-01

306

EGF regulates tyrosine phosphorylation and membrane-translocation of the scaffold protein Tks5  

PubMed Central

Background Tks5/FISH is a scaffold protein comprising of five SH3 domains and one PX domain. Tks5 is a substrate of the tyrosine kinase Src and is required for the organization of podosomes/invadopodia implicated in invasion of tumor cells. Recent data have suggested that a close homologue of Tks5, Tks4, is implicated in the EGF signaling. Results Here, we report that Tks5 is a component of the EGF signaling pathway. In EGF-treated cells, Tks5 is tyrosine phosphorylated within minutes and the level of phosphorylation is sustained for at least 2 hours. Using specific kinase inhibitors, we demonstrate that tyrosine phosphorylation of Tks5 is catalyzed by Src tyrosine kinase. We show that treatment of cells with EGF results in plasma membrane translocation of Tks5. In addition, treatment of cells with LY294002, an inhibitor of PI 3-kinase, or mutation of the PX domain reduces tyrosine phosphorylation and membrane translocation of Tks5. Conclusions Our results identify Tks5 as a novel component of the EGF signaling pathway.

2013-01-01

307

Coal dust alters ?-naphthoflavone-induced aryl hydrocarbon receptor nuclear translocation in alveolar type II cells  

PubMed Central

Background Many polycyclic aromatic hydrocarbons (PAHs) can cause DNA adducts and initiate carcinogenesis. Mixed exposures to coal dust (CD) and PAHs are common in occupational settings. In the CD and PAH-exposed lung, CD increases apoptosis and causes alveolar type II (AT-II) cell hyperplasia but reduces CYP1A1 induction. Inflammation, but not apoptosis, appears etiologically associated with reduced CYP1A1 induction in this mixed exposure model. Many AT-II cells in the CD-exposed lungs have no detectable CYP1A1 induction after PAH exposure. Although AT-II cells are a small subfraction of lung cells, they are believed to be a potential progenitor cell for some lung cancers. Because CYP1A1 is induced via ligand-mediated nuclear translocation of the aryl hydrocarbon receptor (AhR), we investigated the effect of CD on PAH-induced nuclear translocation of AhR in AT-II cells isolated from in vivo-exposed rats. Rats received CD or vehicle (saline) by intratracheal (IT) instillation. Three days before sacrifice, half of the rats in each group started daily intraperitoneal injections of the PAH, ?-naphthoflavone (BNF). Results Fourteen days after IT CD exposure and 1 day after the last intraperitoneal BNF injection, AhR immunofluorescence indicated that proportional AhR nuclear expression and the percentage of cells with nuclear AhR were significantly increased in rats receiving IT saline and BNF injections compared to vehicle controls. However, in CD-exposed rats, BNF did not significantly alter the nuclear localization or cytosolic expression of AhR compared to rats receiving CD and oil. Conclusion Our findings suggest that during particle and PAH mixed exposures, CD alters the BNF-induced nuclear translocation of AhR in AT-II cells. This provides an explanation for the modification of CYP1A1 induction in these cells. Thus, this study suggests that mechanisms for reduced PAH-induced CYP1A1 activity in the CD exposed lung include not only the effects of inflammation on the lung as a whole, but also reduced PAH-associated nuclear translocation of AhR in an expanded population of AT-II cells.

Ghanem, Mohamed M; Battelli, Lori A; Law, Brandon F; Castranova, Vincent; Kashon, Michael L; Nath, Joginder; Hubbs, Ann F

2009-01-01

308

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise.  

PubMed

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background. PMID:9291610

Eckstein, M P; Ahumada, A J; Watson, A B

1997-09-01

309

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise  

NASA Technical Reports Server (NTRS)

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

1997-01-01

310

Gene flow and endangered species translocations: a topic revisited  

Microsoft Academic Search

Understanding the evolutionary role of gene flow is pivotal to the conservation of endangered populations. Gene flow can be enhanced through population translocations that are conducted to maintain genetic variation and combat the negative consequences of inbreeding depression (two of the major concerns in the conservation of subdivided or isolated populations). While researchers have given extensive consideration to the idea

Andrew Storfer

1999-01-01

311

Chromosomal Translocation in a Child with SLI and Apraxia.  

ERIC Educational Resources Information Center

This case study of a 5-year-old boy diagnosed with a specific expressive language impairment with verbal apraxia reports on chromosomal, neurological, speech/language, cognitive, and play evaluations. Evaluation found a chromosomal translocation and a severe expressive speech-language deficit but good nonverbal cognitive and communicative skills.…

Weistuch, Lucille; Schiff-Myers, Naomi B.

1996-01-01

312

Inhibition of adenine nucleotide translocator by lipid peroxidation products  

Microsoft Academic Search

Our previous data showed that aldehydic lipid peroxidation products, interacting with mitochondrial membrane lipids, could alter the physicochemical status of the membrane. This study was initiated to examine the interaction of these aldehydes with a major mitochondrial protein, the adenine nucleotide translocator (ANT). Our findings showed that the transporting activity of ANT in intact mitochondria was inhibited by two unsaturated

Juan Juan Chen; Helen Bertrand; Byung Pal Yu

1995-01-01

313

The impact of translocations and gene fusions on cancer causation  

Microsoft Academic Search

Chromosome aberrations, in particular translocations and their corresponding gene fusions, have an important role in the initial steps of tumorigenesis; at present, 358 gene fusions involving 337 different genes have been identified. An increasing number of gene fusions are being recognized as important diagnostic and prognostic parameters in malignant haematological disorders and childhood sarcomas. The biological and clinical impact of

Bertil Johansson; Fredrik Mertens; Felix Mitelman

2007-01-01

314

DNA Translocating Through a Carbon Nanotube Can Increase Ionic Current  

PubMed Central

DNA translocation through a narrow, single-walled carbon nanotube can be accompanied by large increases of ion current, recently observed in contrast to the ion current blockade. We use molecular dynamics simulations to show large electro-osmotic flow can be turned into a large net current via ion-selective filtering by a DNA molecule inside the carbon nanotube.

Park, Jae Hyun; He, Jin; Gyarfas, Brett; Lindsay, Stuart; Krstic, Predrag S.

2012-01-01

315

Impact of actin on adhesion and translocation of Enterococcus faecalis.  

PubMed

This study focuses on the impact of actin on adhesion and translocation of Enterococcus (E.) faecalis OG1RF, E. faecalis Symbioflor(®), and E. faecalis V583. Insight into the role of actin aggregation in the mediation of bacterial adhesion and translocation was provided by a two-chamber translocation assay, which employed Ptk6 cells. Determination of translocation rates, cytochalasin D treatment, and laser scanning confocal microscopic observation revealed actin as a predominant brace for enterococci to pass through the epithelial cell layer. As the three enterococci had moderate adhesion ability to actin, actin-binding proteins were isolated and characterized by LC-MS/MS. The isolated proteins were identified as pyruvate formate lyase, enolase, glyceraldehyde-3-phosphate dehydrogenase, and GroEL. All these proteins belong to two major groups of moonlighting proteins, i.e., proteins, which display additional functions other than their described major biochemical catalysis. Both groups of moonlight proteins were determined to be associated with epithelial cell binding. PMID:24362949

Peng, Zhen; Krey, Viktoria; Wei, Hua; Tan, Qianglai; Vogelmann, Roger; Ehrmann, Matthias A; Vogel, Rudi F

2014-02-01

316

Mitochondrial translocation of Nur77 mediates cardiomyocyte apoptosis  

PubMed Central

Aims The cascade of events leading to compromised mitochondrial integrity in response to stress is mediated by various combinatorial interactions of pro- and anti-apoptotic molecules. Nur77, an immediate early gene that encodes a nuclear orphan receptor, translocates from the nucleus to mitochondria to induce cytochrome c release and apoptosis in cancer cells in response to various pro-apoptotic treatments. However, the role of Nur77 in the cardiac setting is still unclear. The objective of this study is to determine the physiological relevance and pathophysiological importance of Nur77 in cardiomyocytes. Methods and results Myocardial Nur77 is upregulated following cardiomyopathic injury and, while expressed in the postnatal myocardium, declines in level within weeks after birth. Nur77 is localized predominantly in cardiomyocyte nuclei under normal conditions where it is not apoptotic, but translocates to mitochondria in response to oxidative stress both in vitro and in vivo. Mitochondrial localization of Nur77 induces cytochrome c release and typical morphological features of apoptosis, including chromatin condensation and DNA fragmentation. Knockdown of Nur77 rescued hydrogen peroxide-induced cardiomyocyte apoptosis. Conclusion Translocation of Nur77 from the nucleus to the mitochondria in cardiomyocytes results in the loss of mitochondrial integrity and subsequent apoptosis in response to ischaemia/reperfusion injury. Our findings identify Nur77 as a novel mediator of cardiomyocyte apoptosis and warrants further investigation of mitochondrial Nur77 translocation as a mechanism to control cell death in the treatment of ischaemic heart diseases.

Cheng, Zhaokang; Volkers, Mirko; Din, Shabana; Avitabile, Daniele; Khan, Mohsin; Gude, Natalie; Mohsin, Sadia; Bo, Tao; Truffa, Silvia; Alvarez, Roberto; Mason, Matt; Fischer, Kimberlee M.; Konstandin, Mathias H.; Zhang, Xiao-kun; Heller Brown, Joan; Sussman, Mark A.

2011-01-01

317

Translocation and depuration of 137 Cs in tea plants  

Microsoft Academic Search

Translocation and percent distribution of137Cs in different parts of the tea plant have been investigated from the foliar aborption and root uptake in Chemobyl contaiminated soil during 1987–1994. The results showed that the transfer of the radionuclide from soil to the plant occurred only in the roots during this long period. On the other hand, the present data confirmed that

S. Topcuo?lu; N. Güngör; A. Köse; A. Varinlio?lu

1997-01-01

318

Human reciprocal translocations: is the unbalanced mode at birth predictable?  

Microsoft Academic Search

Two methods of prediction for the risk of unbalance at birth were tested on a large data base of reciprocal translocation (1376 families): the pachyten diagram predictive method (PDPmethod) and the discriminant method (Dmethod). These method succeeded in correctly predicting the segregation mode in 66% of the data for the PDPmethod and in 80% of the data for the Dmethod.

Christine Cans; Olivier Cohen; Marie-Ange Mermet; Jacques Demongeot; Pierre Jalbert

1993-01-01

319

Cartographic study: Breakpoints in 1574 families carrying human reciprocal translocations  

Microsoft Academic Search

Reciprocal translocations (rcp) are among the most common constitutional chromosomal aberrations in man. Using a European database of 1574 families carrying autosomal rep, a cartographic study was done on the breakpoints involved. The breakpoints are non-randomly distributed along the different chromosomes, indicating hot spots. Breakpoints of rep that result in descendants that are unbalanced chromosomally at birth are more frequent

Olivier Cohen; Christine Cans; Jean Louis Gilardi; Hubert Roth; Marie-Ange Mermet; Pierre Jalbert; Jacques Demongeot; Martine Cuillel

1996-01-01

320

Reciprocal translocation versus centric fusion between two No. 13 chromosomes  

Microsoft Academic Search

The centric fusion, or Robertsonian, type of translocation has been considered as a fusion of the entire long arms of two acrocentric chromosomes preceded by breakage of the centric heterochromatin. Reunion of the long arms is considered to include the centromeres, only one of which is visible by conventional staining methods. Prior to the development of the current banding techniques

Lillian Y. F. Hsu; Hyon J. Kim; Eva Sujansky; B. Kousseff; K. Hirschhorn

1973-01-01

321

Diphtheria toxin translocation across cellular membranes is regulated by sphingolipids  

SciTech Connect

Diphtheria toxin is translocated across cellular membranes when receptor-bound toxin is exposed to low pH. To study the role of sphingolipids for toxin translocation, both a mutant cell line lacking the first enzyme in de novo sphingolipid synthesis, serine palmitoyltransferase, and a specific inhibitor of the same enzyme, myriocin, were used. The serine palmitoyltransferase-deficient cell line (LY-B) was found to be 10-15 times more sensitive to diphtheria toxin than the genetically complemented cell line (LY-B/cLCB1) and the wild-type cell line (CHO-K1), both when toxin translocation directly across the plasma membrane was induced by exposing cells with surface-bound toxin to low pH, and when the toxin followed its normal route via acidified endosomes into the cytosol. Toxin binding was similar in these three cell lines. Furthermore, inhibition of serine palmitoyltransferase activity by addition of myriocin sensitized the two control cell lines (LY-B/cLCB1 and CHO-K1) to diphtheria toxin, whereas, as expected, no effect was observed in cells lacking serine palmitoyltransferase (LY-B). In conclusion, diphtheria toxin translocation is facilitated by depletion of membrane sphingolipids.

Spilsberg, Bjorn [Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway); Hanada, Kentaro [Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640 (Japan); Sandvig, Kirsten [Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway)]. E-mail: ksandvig@radium.uio.no

2005-04-08

322

DNA translocation through low-noise glass nanopores.  

PubMed

The effect of electron irradiation-induced shrinking on glass nanocapillaries with diameters ranging from 75 to 14 nm was analyzed by measuring the conductance characteristics with and without DNA translocation. We have investigated nanocapillary shrinking with a scanning electron microscope from several perspectives to understand the geometry of the shrunken nanocapillary. On the basis of this observation, the conductance was modeled with respect to the nanocapillary diameter, which allowed reproducing the experimental results. We then translocated DNA through the shrunken nanocapillaries and measured higher conductance drops for smaller diameters, reaching 1.7 nS for the 14 nm diameter nanocapillary. A model taking into account the conical shape of the shrunken nanocapillaries also supported this dependence. Next, we calculated the noise in the form of the standard deviation of the ionic conductance (between 0.04 and 0.15 nS) to calculate a signal-to-noise ratio (SNR) and compared it with nanopores embedded in 20 nm thick silicon nitride membranes. This shows that although nanocapillaries have smaller signal amplitudes due to their conical shape, they benefit from a lower noise. The glass nanocapillaries have a good SNR of about 25 compared with the SNR of 15 for smaller sized nanopores in silicon nitride membranes. The ability to use a modified model of nanopores to mimic the block conductance by DNA translocation provides a theoretical framework to support experimental results from translocating polymers such as DNA. PMID:24274458

Steinbock, Lorenz J; Bulushev, Roman D; Krishnan, Swati; Raillon, Camille; Radenovic, Aleksandra

2013-12-23

323

Training Captive-Bred or Translocated Animals to Avoid Predators  

Microsoft Academic Search

Animal reintroductions and translocations are potentially important interventions to save species from extinction, but most are unsuccessful. Mortality due to predation is a principal cause of failure. Animals that have been isolated from predators, either throughout their lifetime or over evolutionary time, may no longer express appropriate antipredator behavior. For this reason, conservation biologists are beginning to include antipredator training

Andrea S. Griffin; Daniel T. Blumstein; Christopher S. Evans

2000-01-01

324

Bacterial translocation in the rat model of lectin induced diarrhoea.  

PubMed Central

Red kidney beans were fed to weanling Long-Evans rats to cause diarrhoea (mean (SD) faecal wet weight: 2.66 (0.73) g/day in six rats fed beans v 1.12 (0.47) g/day in six control rats, p < 0.01) and increased faecal energy loss (4.87 (0.41) v 2.14 (0.23) kcal/day, p < 0.01). In addition, the rats fed beans had heavier small intestines (80.6 (4.6) v 51.9 (8.4) g/kg body weight, p < 0.01), heavier mesenteric lymph nodes (0.72 (0.27) v 0.08 (0.08) g/kg body weight, p < 0.05), and translocation of indigenous intestinal bacteria, Citrobacter Spp and Escherichia coli, to the mesenteric lymph nodes. (Translocation positive, that is, > 100 colonies per g of nodal tissue: 75% v 0%, p < 0.005.) These data suggest that diarrhoea induced by red kidney beans is a suitable model for studies of an important cause of persistent diarrhoea--that is, systemic complications. This rat model of lectin induced diarrhoea with translocation of intraluminal enteric bacteria into mesenteric lymph nodes should be useful in understanding the well known septicaemic complications associated with prolonged diarrhoea in infants and small children and in studies on factors that may modify or prevent bacterial translocation.

Shoda, R; Mahalanabis, D; Wahed, M A; Albert, M J

1995-01-01

325

Applying ICC? to DNA translocation: Effect of dielectric boundaries  

NASA Astrophysics Data System (ADS)

The translocation process of a single DNA molecule through a synthetic nanopore is investigated with the help of ICC, a fast and accurate algorithm which allows to take into account dielectric boundary forces (DBF) in molecular dynamics simulations. We show that dielectric contrast between water and membrane material is responsible for a remarkably high free energy barrier at low salt concentrations.

Kesselheim, Stefan; Sega, Marcello; Holm, Christian

2011-01-01

326

HSP70 inhibits Bax translocation during Photofrin-PDT apoptosis  

NASA Astrophysics Data System (ADS)

Apoptosis is an important cellular event that plays a key role in therapy of many diseases. The mechanisms of the initiation and regulation of photodynamic therapy (PDT) -induced apoptosis is complex. Some PDT-associated apoptosis pathways involved plasma membrane death receptors, mitochondria, lysosomes and endoplasmic reticulum (ER). Our previous study found that Photofrin were localized primarily in mitochondria, the primary targets of Photofrin-PDT. The key role of Bax in the mitochondrion-mediated apoptosis has been demonstrated in many systems. In order to determine the role of Bax in the mitochondrion-mediated apoptosis induced by Photofrin-PDT, we used the CFP/GFP-Bax plasmid to monitor the dynamics of Bax activation and translocation after PDT treatment. With laser scanning confocal microscopy, we found that PDT induced Bax translocation from the cytosol to mitochondria; however, with cells over-expressing YFP-HSP70 plasmids, Bax translocation was not detected. Thus, for Photofrin-PDT, Bax activation and translocation were inhibited by HSP70, not influence the cell death.

Zhou, Feifan; Chen, Wei R.; Song, Sheng

2009-02-01

327

Functional significance of differential eNOS translocation.  

PubMed

Nitric oxide (NO) regulates flow and permeability. ACh and platelet-activating factor (PAF) lead to endothelial NO synthase (eNOS) phosphorylation and NO release. While ACh causes only vasodilation, PAF induces vasoconstriction and hyperpermeability. The key differential signaling mechanisms for discriminating between vasodilation and hyperpermeability are unknown. We tested the hypothesis that differential translocation may serve as a regulatory mechanism of eNOS to determine specific vascular responses. We used ECV-304 cells permanently transfected with eNOS-green fluorescent protein (ECVeNOS-GFP) and demonstrated that the agonists activate eNOS and reproduce their characteristic endothelial permeability effects in these cells. We evaluated eNOS localization by lipid raft analysis and immunofluorescence microscopy. After PAF and ACh, eNOS moves away from caveolae. eNOS distributes both in the plasma membrane and Golgi in control cells. ACh (10(-5) M, 10(-4) M) translocated eNOS preferentially to the trans-Golgi network (TGN) and PAF (10(-7) M) preferentially to the cytosol. We suggest that PAF-induced eNOS translocation preferentially to cytosol reflects a differential signaling mechanism related to changes in permeability, whereas ACh-induced eNOS translocation to the TGN is related to vasodilation. PMID:16679407

Sánchez, Fabiola A; Savalia, Nirav B; Durán, Ricardo G; Lal, Brajesh K; Boric, Mauricio P; Durán, Walter N

2006-09-01

328

Functional significance of differential eNOS translocation  

PubMed Central

Nitric oxide (NO) regulates flow and permeability. ACh and platelet-activating factor (PAF) lead to endothelial NO synthase (eNOS) phosphorylation and NO release. While ACh causes only vasodilation, PAF induces vasoconstriction and hyperpermeability. The key differential signaling mechanisms for discriminating between vasodilation and hyperpermeability are unknown. We tested the hypothesis that differential translocation may serve as a regulatory mechanism of eNOS to determine specific vascular responses. We used ECV-304 cells permanently transfected with eNOS-green fluorescent protein (ECVeNOS-GFP) and demonstrated that the agonists activate eNOS and reproduce their characteristic endothelial permeability effects in these cells. We evaluated eNOS localization by lipid raft analysis and immunofluorescence microscopy. After PAF and ACh, eNOS moves away from caveolae. eNOS distributes both in the plasma membrane and Golgi in control cells. ACh (10?5 M, 10?4 M) translocated eNOS preferentially to the trans-Golgi network (TGN) and PAF (10?7 M) preferentially to the cytosol. We suggest that PAF-induced eNOS translocation preferentially to cytosol reflects a differential signaling mechanism related to changes in permeability, whereas ACh-induced eNOS translocation to the TGN is related to vasodilation.

Sanchez, Fabiola A.; Savalia, Nirav B.; Duran, Ricardo G.; Lal, Brajesh K.; Boric, Mauricio P.; Duran, Walter N.

2006-01-01

329

Oncogene Translocations and Non-Hodgkin Lymphoma (NHL)  

Cancer.gov

A colloboration with several large population-based cohorts to determine whether the prevalence or level of t14;18 is associated with risk of NHL and to investigate the clonal relationship between translocation-bearing cells and subsequent tumors

330

Polymer translocation through a nanopore studied by Langevin dynamics  

NASA Astrophysics Data System (ADS)

Polymer translocation through a nanopore has gained considerable attention in recent years, due to its potential application in DNA-sequencing. The design of a corresponding device requires a full understanding of the translocation dynamics. The scaling of polymer translocation time ? with polymer chain length N is an important measure of the underlying dynamics. A recent experimentootnotetextA. J. Storm et al., arXiv q-bio/0404041 (2004). has uncovered a scaling behavior ?N^1.26 that differs from the linear law observed in other experiments. To explain this newly-observed scaling behavior, we have employed Langevin dynamics simulations. Using a bead--spring model for the polymer chain and a membrane composed of one layer of hard-sphere particles, we have studied a wide range of chain lengths 20 <=N <=640, for different friction coefficients ?. A crossover scaling behavior was found for ?, which is controlled by both N and ?. We explain the measured scaling behavior from the chain conformations and instantaneous translocation velocities.

Guo, Lei

2005-03-01

331

Dynamics of DNA translocation through an attractive nanopore  

NASA Astrophysics Data System (ADS)

We investigate the dynamics of single-stranded DNA translocation through a nanopore driven by an external force using Langevin dynamics simulations in two dimensions to study how the translocation dynamics depend on the details of the DNA sequences. We consider a coarse-grained model of DNA built from two bases A and C , having different base-pore interactions, e.g., a strong (weak) attractive force between the pore and the base A (C) inside the pore. From a series of studies on hetero-DNAs with repeat units AmCn , we find that the translocation time decreases exponentially as a function of the volume fraction fC of the base C . For longer A sequences with fC?0.5 , the translocation time strongly depends on the orientation of DNA, namely which base enters the pore first. Our studies clearly demonstrate that for a DNA of certain length N with repeat units AmCn , the pattern exhibited by the waiting times of the individual bases and their periodicity can unambiguously determine the values of m , n , and N , respectively. Therefore, a prospective experimental realization of this phenomenon may lead to fast and efficient sequence detection.

Luo, Kaifu; Ala-Nissila, Tapio; Ying, See-Chen; Bhattacharya, Aniket

2008-12-01

332

DNA Translocation through a Peridically Patterned Pyramidal Probe  

NASA Astrophysics Data System (ADS)

The Al nanoapertures surrounded by periodic patterns on the pyramid were fabricated. The nanosize aperture surrounded by equidistant elliptic groove patterns presented greater transmission than the aperture with circular groove patterns. The translocation of ?-DNA through these fabricated nanostructures was examined.

Choi, Seong Soo; Park, Myoung Jin; Kyoo Park, Nam; Park, Seung Min; Lee, Luke

2013-03-01

333

Accumulation and translocation of 198Hg in four crop species.  

PubMed

The uptake and transport of mercury (Hg) through vegetation play an important role in the biogeochemical cycling of Hg. However, quantitative information regarding Hg translocation in plants is poorly understood. In the present study, Hg uptake, accumulation, and translocation in 4 crops-rice (Oryza.sativa?L.), wheat (Triticum?L.), corn (Zea mays L.), and oilseed rape (Brassica campestris L.)-grown in Hoagland solution were investigated using a stable isotope ((198)Hg) tracing technique. The distribution of (198)Hg in root, stem, and leaf after uptake was quantified, and the release of (198)Hg into the air from crop leaf was investigated. It was found that the concentration of Hg accumulated in the root, stem, and leaf of rice increased linearly with the spiked (198)Hg concentration. The uptake equilibrium constant was estimated to be 2.35?mol Hg/g dry weight in rice root per mol/L Hg remaining in the Hoagland solution. More than 94% of (198)Hg uptake was accumulated in the roots for all 4 crops examined. The translocation to stem and leaf was not significant because of the absence of Hg(2+) complexes that facilitate Hg transport in plants. The accumulated (198)Hg in stem and leaf was not released from the plant at air Hg(0) concentration ranging from 0?ng/m(3) to 10?ng/m(3). Transfer factor data analysis showed that Hg translocation from stems to leaves was more efficient than that from roots to stems. PMID:24173818

Cui, Liwei; Feng, Xinbin; Lin, Che-Jen; Wang, Xinming; Meng, Bo; Wang, Xun; Wang, Heng

2014-02-01

334

Nuclear translocation of the cytoplasmic domain of HB-EGF induces gastric cancer invasion  

PubMed Central

Background Membrane-anchored heparin-binding epidermal growth factor-like growth factor (proHB-EGF) yields soluble HB-EGF, which is an epidermal growth factor receptor (EGFR) ligand, and a carboxy-terminal fragment of HB-EGF (HB-EGF-CTF) after ectodomain shedding. We previously reported that HB-EGF-CTF and unshed proHB-EGF which has the cytoplasmic domain of proHB-EGF (HB-EGF-C), translocate from the plasma membrane to the nucleus and regulate cell cycle after shedding stimuli. However, the significance of nuclear exported HB-EGF-C in human gastric cancer is unclear. Methods We investigated the relationship between intracellular localization of HB-EGF-C and clinical outcome in 96 gastric cancer patients treated with gastrectomy. Moreover, we established stable gastric cancer cell lines overexpressing wild-type HB-EGF (wt-HB-EGF) and mutated HB-EGF (HB-EGF-mC), which prevented HB-EGF-C nuclear translocation after shedding. Cell motility between these 2 gastric cancer cell lines was investigated using a transwell invasion assay and a wound healing assay. Results Of the 96 gastric cancer cases, HB-EGF-C immunoreactivity was detected in both the nucleus and cytoplasm in 19 cases (19.8?%) and in the cytoplasm only in 25 cases (26.0?%). The nuclear immunoreactivity of HB-EGF-C was significantly increased in stage pT3/4 tumors compared with pT1/2 tumors (T1/2 vs. T3/4: 11.1?% vs. 36.4?%, P?translocation induce gastric cancer growth, whereas HB-EGF-C nuclear translocation independently plays a critical role in gastric cancer invasion. The present study demonstrated that HB-EGF-C nuclear translocation might be crucial in gastric cancer invasion. HB-EGF-C nuclear translocation may offer a prognostic marker and a new molecular target for gastric cancer therapy.

2012-01-01

335

Modification of the DNA content in translocated regions of Drosophila polytene chromosomes  

Microsoft Academic Search

The DNA content of translocated polytene chromosome regions in Drosophila melanogaster is affected by heterochromatic position effect. Microdensitometric studies on wm258-21 translocation heterozygotes showed (Hartmann-Goldstein and Cowell, 1976; Cowell and Hartmann Goldstein, 1980) that band region 3D1-E2, adjacent to the breakpoint, contained less DNA than the homologous non-translocated region whereas the neighbouring 3C1-10 region contained more DNA than its non-translocated

J. K. Cowell; I. J. Hartmann-Goldstein

1980-01-01

336

Optimal adaptive management for the translocation of a threatened species.  

PubMed

Active adaptive management (AAM) is an approach to wildlife management that acknowledges our imperfect understanding of natural systems and allows for some resolution of our uncertainty. Such learning may be characterized by risky strategies in the short term. Experimentation is only considered acceptable if it is expected to be repaid by increased returns in the long term, generated by an improved understanding of the system. By setting AAM problems within a decision theory framework, we can find this optimal balance between achieving our objectives in the short term and learning for the long term. We apply this approach to managing the translocation of the bridled nailtail wallaby (Onychogalea fraenata), an endangered species from Queensland, Australia. Our task is to allocate captive-bred animals, between two sites or populations to maximize abundance at the end of the translocation project. One population, at the original site of occupancy, has a known growth rate. A population potentially could be established at a second site of suitable habitat, but we can only learn the growth rate of this new population by monitoring translocated animals. We use a mathematical programming technique called stochastic dynamic programming, which determines optimal management decisions for every possible management trajectory. We find optimal strategies under active and passive adaptive management, which enables us to examine the balance between learning and managing directly. Learning is more often optimal when we have less prior information about the uncertain population growth rate at the new site, when the growth rate at the original site is low, and when there is substantial time remaining in the translocation project. Few studies outside the area of optimal harvesting have framed AAM within a decision theory context. This is the first application to threatened species translocation. PMID:19323207

Rout, Tracy M; Hauser, Cindy E; Possingham, Hugh P

2009-03-01

337

Rab10 in insulin-stimulated GLUT4 translocation.  

PubMed

In fat and muscle cells, insulin stimulates the movement to and fusion of intracellular vesicles containing GLUT4 with the plasma membrane, a process referred to as GLUT4 translocation. Previous studies have indicated that Akt [also known as PKB (protein kinase B)] phosphorylation of AS160, a GAP (GTPase-activating protein) for Rabs, is required for GLUT4 translocation. The results suggest that this phosphorylation suppresses the GAP activity and leads to the elevation of the GTP form of one or more Rabs required for GLUT4 translocation. Based on their presence in GLUT4 vesicles and activity as AS160 GAP substrates, Rabs 8A, 8B, 10 and 14 are candidate Rabs. Here, we provide further evidence that Rab10 participates in GLUT4 translocation in 3T3-L1 adipocytes. Among Rabs 8A, 8B, 10 and 14, only the knockdown of Rab10 inhibited GLUT4 translocation. In addition, we describe the subcellular distribution of Rab10 and estimate the fraction of Rab10 in the active GTP form in vivo. Approx. 5% of the total Rab10 was present in GLUT4 vesicles isolated from the low-density microsomes. In both the basal and the insulin state, 90% of the total Rab10 was in the inactive GDP state. Thus, if insulin increases the GTP form of Rab10, the increase is limited to a small portion of the total Rab10. Finally, we report that the Rab10 mutant considered to be constitutively active (Rab10 Q68L) is a substrate for the AS160 GAP domain and, hence, cannot be used to deduce rigorously the function of Rab10 in its GTP form. PMID:18076383

Sano, Hiroyuki; Roach, William G; Peck, Grantley R; Fukuda, Mitsunori; Lienhard, Gustav E

2008-04-01

338

Identification of rye chromosomes: the Giemsa banding pattern and the translocation tester set  

Microsoft Academic Search

The Giemsa banding pattern is given for eleven reciprocal translocations of rye, Secale cereale L., together involving all chromosomes at least once, and one telocentric substitution. It is possible to correlate the identification system based on the Giemsa pattern with that based on the translocation tester set. The location of the translocation break points could be determined very exactly for

J. M. de Vries; J. Sybenga

1976-01-01

339

Logistic regression model to estimate the risk of unbalanced offspring in reciprocal translocations  

Microsoft Academic Search

The aim of this study was to estimate the risk of viable unbalanced offspring for a parental carrier of reciprocal translocation. On a large computerized database of reciprocal translocations we used logistic regression to model this risk. The status of the progeny is the outcome variable. Explanatory covariates are cytogenetic characteristics of the translocation, age and sex of the parental

Christine Cans; Olivier Cohen; Christian Lavergne; Marie-Ange Mermet; Jacques Demongeot; Pierre Jalbert

1993-01-01

340

Translocation as a conservation tool: site fidelity and movement of repatriated gopher tortoises (Gopherus polyphemus)  

Microsoft Academic Search

Efforts to evaluate the efficacy of translocation as a conservation tool have mostly been inadequate, particularly for reptiles and amphibians, leading many biologists to discount translocation as a viable management option. Nevertheless, with two-thirds of the world's tortoise and freshwater turtle species at risk, translocation may be one of the few remaining options for re-establishing extirpated populations and reconnecting fragmented

Tracey D. Tuberville; Erin E. Clark; Kurt A. Buhlmann; J. Whitfield Gibbons

2005-01-01

341

Reverse DNA translocation through a solid-state nanopore by magnetic tweezers  

Microsoft Academic Search

Voltage-driven DNA translocation through nanopores has attracted wide interest for many potential applications in molecular biology and biotechnology. However, it is intrinsically difficult to control the DNA motion in standard DNA translocation processes in which a strong electric field is required in drawing DNA into the pore, but it also leads to uncontrollable fast DNA translocation. Here we explore a

Hongbo Peng; Xinsheng Sean Ling

2009-01-01

342

Factors affecting the success of translocations of the black-faced impala in Namibia  

Microsoft Academic Search

This study analysed 21 translocations of the vulnerable black-faced impala (Aepyceros melampus petersi) to 20 Namibian game farms that occurred between 1970 and 2001, seeking characteristics of the translocated populations and the release sites that significantly correlated with the success of the translocations. Characteristics considered were: initial population size; presence of cheetah and leopard; area; habitat type; occurrence within the

Tammie K. Matson; Anne W. Goldizen; Peter J. Jarman

2004-01-01

343

The dual-frequency scatterometer reexamined  

NASA Technical Reports Server (NTRS)

The utility of dual frequency scatterometers in measuring ocean wave directional spectra can be increased by adding third frequency to the system. The background which effectively limits signal detectability in dual frequency operation can be made a part of the signal through the addition of this third frequency. Signal detectability is limited only by system thermal noise and space based operation becomes more feasible.

Plant, W. J.; Reeves, A. B.

1984-01-01

344

Pleiotropic effects of the twin-arginine translocation system on biofilm formation, colonization, and virulence in Vibrio cholerae  

PubMed Central

Background The Twin-arginine translocation (Tat) system serves to translocate folded proteins, including periplasmic enzymes that bind redox cofactors in bacteria. The Tat system is also a determinant of virulence in some pathogenic bacteria, related to pleiotropic effects including growth, motility, and the secretion of some virulent factors. The contribution of the Tat pathway to Vibrio cholerae has not been explored. Here we investigated the functionality of the Tat system in V. cholerae, the etiologic agent of cholera. Results In V. cholerae, the tatABC genes function in the translocation of TMAO reductase. Deletion of the tatABC genes led to a significant decrease in biofilm formation, the ability to attach to HT-29 cells, and the ability to colonize suckling mouse intestines. In addition, we observed a reduction in the output of cholera toxin, which may be due to the decreased transcription level of the toxin gene in tatABC mutants, suggesting an indirect effect of the mutation on toxin production. No obvious differences in flagellum biosynthesis and motility were found between the tatABC mutant and the parental strain, showing a variable effect of Tat in different bacteria. Conclusion The Tat system contributes to the survival of V. cholerae in the environment and in vivo, and it may be associated with its virulence.

2009-01-01

345

Cosmic Microwave Background Polarization and Inflation  

NASA Technical Reports Server (NTRS)

Measurements of the cosmic microwave background (CMB) offer a means to explore the universe at a very early epoch. Specifically, if the universe went through a brief period of exponential expansion called inflation as current data suggest, gravitational waves from this period would polarize the CMB in a specific pattern. At GSFC, we are currently working towards two experiments that work in concert to measure this polarization pattern in search of evidence for inflation. The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization at frequencies between 40 and 150 GHz from the Atacama Desert in Chile. The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment that will make similar measurements at frequencies between 200 and 600 GHz.

Chuss, David T.

2011-01-01

346

Optical detection of DNA translocation through silicon nanopore by ultraviolet light  

NASA Astrophysics Data System (ADS)

In this paper, we propose a new optical detection scheme for nanopore-based DNA sequencing with high resolution towards eventual base identification. We use ultraviolet light for excitation of a fluorescent probe attached to DNA and a nanopore in the silicon membrane that has a significantly large refractive index and an extinction coefficient at ultraviolet wavelengths. In this study, numerical electromagnetic simulation revealed that the z-polarization component (perpendicular to the membrane plane) of the electric field was dominant near the nanopore and generated a large electric field gradient at the nanopore exit, typically with a decay length of 2 nm for a nanopore with diameter of 7 nm. The large extinction coefficient contributed to reduction in background noise coming from fluorophore-labeled DNA strands that remain behind the membrane (the cis side of the membrane). We observed a high signal-to-noise ratio of single DNA translocation events under the application of an electric field.

Yamazaki, Hirohito; Kimura, Shinji; Tsukahara, Mutsumi; Esashika, Keiko; Saiki, Toshiharu

2014-04-01

347

Voltage-driven translocation behaviors of IgG molecule through nanopore arrays  

PubMed Central

Nanopore-based biosensing has attracted more and more interests in the past years, which is also regarded as an emerging field with major impact on bio-analysis and fundamental understanding of nanoscale interactions down to single-molecule level. In this work, the voltage-driven translocation properties of goat antibody to human immunoglobulin G (IgG) are investigated using nanopore arrays in polycarbonate membranes. Obviously, the background ionic currents are modulated by IgG molecules for their physical place-holding effect. However, the detected ionic currents do ‘not’ continuously decrease as conceived; the currents first decrease, then increase, and finally stabilize with increasing IgG concentration. To understand this phenomenon, a simplified model is suggested, and the calculated results contribute to the understanding of the abnormal phenomenon in the actual ionic current changing tendency.

2013-01-01

348

Xp 11.2 translocation renal carcinoma in young adults; recently classified distinct subtype  

PubMed Central

Background XP11.2 renal translocation carcinomas are often encountered in paediatric group of patients where they are believed to be rather indolent. They are rare but more aggressive in young adults. They are slow growing, sometimes without characteristic symptoms and their biologic behaviour is uncertain. Case report We report two cases of this type of tumour in Slovenian young adult males with long and unusual history. Tumours were confirmed imunohistologically by positive reaction for CD10, P504S and TFE3. Conclusions According to the indications in the literature prognosis of these tumours in young adults depends upon the stage. It seems that cysts, haematomas and necrosis around the kidney are often encountered in these tumours. In advanced stage with lymph nodes involvement or distant metastases, the prognosis is poor. Surgery seems to be basic mode of therapy.

Kmetec, Andrej; Jeruc, Jera

2014-01-01

349

Discriminability measures for predicting readability of text on textured backgrounds  

NASA Technical Reports Server (NTRS)

Several discriminability measures were examined for their ability to predict reading search times for three levels of text contrast and a range of backgrounds (plain, a periodic texture, and four spatial-frequency-filtered textures created from the periodic texture). Search times indicate that these background variations only affect readability when the text contrast is low, and that spatial frequency content of the background affects readability. These results were not well predicted by the single variables of text contrast (Spearman rank correlation = -0.64) and background RMS contrast (0.08), but a global masking index and a spatial-frequency-selective masking index led to better predictions (-0.84 and -0.81, respectively). c2000 Optical Society of America.

Scharff, L. F.; Hill, A. L.; Ahumada, A. J. Jr; Watson, A. B. (Principal Investigator)

2000-01-01

350

Cosmic Background Explorer (COBE): Emergency support  

NASA Technical Reports Server (NTRS)

The Cosmic Background Explorer (COBE) Mission will measure the diffuse radiation from the universe in the wavelength band 1 micron to 9.6 mm. The band includes the 3 K cosmic background radiation, the known relic of the primeval cosmic explosion. The COBE satellite will be launched from the Western Space and Missile Center (EWSMC) via a Delta launch vehicle into a circular parking orbit of about 300 km. COBE will be placed into a 900-km altitude circular orbit. Coverage will be provided by the Deep Space Network (DSN) for COBE emergencies that would prevent communications via the normal channels of the Tracking and Data Relay Satellite System (TDRSS). Emergency support will be provided by the DSN 26-m subnetwork. Information is given in tabular form for DSN network support, frequency assignments, telemetry, and command.

Stanford, R.; Mattson, R.

1991-01-01

351

Balanced nonacrocentric whole-arm reciprocal translocations: A de novo case and literature review  

SciTech Connect

We report a new de novo case of a balanced whole-arm reciprocal translocation, detected at prenatal diagnosis for late maternal age. A review of previous cases indicates there is a risk of chromosomally abnormal liveborn offspring when a parent is a carrier of this type of translocation, particularly when the translocated region is a small chromosomal segment. Due to the limited number of cases, exact reproductive risks are not available. This is the second example of such a translocation of chromosomes 1 and 5, raising the possibility of nonrandom involvement of certain chromosomes in balanced nonacrocentric whole-arm reciprocal translocations. 18 refs., 1 fig., 1 tab.

Farrell, S.A.; Fan, Y.S. [Credit Valley Hospital, Ontario (Canada)

1995-02-13

352

Entropic effects in formation of chromosome territories: towards understanding of radiation-induced gene translocation frequency  

NASA Astrophysics Data System (ADS)

A detailed understanding of structural organization of biological target, such as geometry of an inter-phase chromosome, is an essential prerequisite for gaining deeper insight into relationship between radiation track structure and radiation-induced biological damage [1]. In particular, coupling of biophysical models aimed to describe architecture of chromosomes and their positioning in a cell nucleus [2-4] with models of local distribution of ionizations caused by passing projectiles, are expected to result in more accurate estimates of aberration induction caused by radiation. There is abundant experimental evidence indicating that arrangements of chromosomes in eukaryotic cell nucleus is non-random and has been evolutionary conserved in specific cell types. Moreover, the radial position of a given chromosome territory (CT) within the cell nucleus has been shown to correlate with its size and gene density. Usually it is assumed that chromosomal geometry and positioning result from the action of specific forces acting locally, such as hydrogen bonds, electrostatic, Van der Waals or hydrophobic interactions operating between nucleosomes and within their interiors. However, it is both desirable and instructive to learn to what extend organization of inter-phase chromosomes is affected by nonspecific entropic forces. In this study we report results of a coarse-grained analysis of a chromatin structure modeled by two distinct approaches. In the first method, we adhere to purely statistical analysis of chromatin packing within a chromosome territory. On the basis of the polymer theory, the chromatin fiber of diameter 30nm is approximated by a chain of spheres, each corresponding to about 30 kbp. Random positioning of the center of the domain is repeated for 1000 spherical nuclei. Configuration of the domain is determined by a random packing of a polymer (a string of identical beads) in estimated fraction of space occupied by a chromosome of a given length and mass. The degree of condensation of the chromatin fiber is modeled by changing length of the string: e.g. loosening of the structure is achieved by distributing the chromosome mass into a higher number of smaller beads and tighter configuration corresponds to a lower number of fragments (balls) with a bigger radius. Additionally, for each configuration, a degree of possible overlapping between domains is assumed. This procedure effectively intensifies loosening/tightening of the chromosome structure by changing the radial dimension of the domain while keeping a constant volume of the polymer chain. Such a positioning model is confronted with a minimalistic molecular dynamics model [5] on a similar structure, in which a chain of beads becomes connected by entropic spring energy and subjected to thermal fluctuations. Comparison of both Monte Carlo models allows to discuss variability of possible configurations as observed in static and dynamic models of chromosome territories along with the effect of compaction and relative arrangements of territorial polymer structures. Acknowledgements: Project is operated within the Foundation for Polish Science International Ph.D. Projects Programme co-financed by the European Regional Development Fund covering, under the agreement no. MPD/2009/6, the Jagiellonian University International Ph.D. Studies in Physics of Complex Systems. References: [1] F. Ballarini, M. Biaggi, and A. Ottolenghi, Radiation Protection Dosimetry 99, 175 (2002). [2] M. Nicodemi and A. Prisco, Biophysical Journal 96, 2168 (2009). [3] P. Cook and D. Marenduzzo, Journal of Cell Biology 186, 825 (2009). [4] M. Tark-Dame, R. van Driel, and D. Heermann, Journal of Cell Science 124, 839 (2011). [5] W. Swope, H. Andersen, P. Berens, and K. Wilson, J. Chem. Phys. 76, 637 (1982).

Gudowska-Nowak, Ewa; Ritter, Sylvia; Durante, Marco; Deperas-Standylo, Joanna; Ciesla, Michal

2012-07-01

353

Background reduction in cryogenic detectors  

SciTech Connect

This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.

Bauer, Daniel A.; /Fermilab

2005-04-01

354

The cosmic microwave background radiation  

Microsoft Academic Search

The discovery of the cosmic microwave background radiation is discussed beginning with radio astronomical measuring techniques, followed by the history of the detection of background radiation, and a summary of some of its properties. Attention is given to the design and operation of a radiotelescope, its antenna and radiometer, exhibiting its advantages, including the ability to measure a collecting area

R. W. Wilson

1979-01-01

355

The cosmic microwave background radiation  

Microsoft Academic Search

We summarize the theoretical and observational status of the study of the Cosmic Microwave Background radiation. Its thermodynamic spectrum is a robust prediction of the Hot Big Bang cosmology and has been confirmed observationally. There are now 75 observations of Cosmic Microwave Background anisotropy, which we present in a table with references. We discuss the theoretical origins of these anisotropies

Eric Gawiser; Joseph Silk

2000-01-01

356

Simulation of HEAO 3 Background.  

National Technical Information Service (NTIS)

A Monte Carlo technique for modeling background in space-based gamma- ray telescopes has been developed. The major background components included in this modeling technique are the diffuse cosmic gamma-ray flux, the Earth's atmospheric flux, the decay of ...

B. F. Phlips B. L. Graham J. D. Kurfess R. A. Kroeger

2007-01-01

357

Frequency-Shift Hearing Aid  

NASA Technical Reports Server (NTRS)

Proposed hearing aid maps spectrum of speech into band of lower frequencies at which ear remains sensitive. By redirecting normal speech frequencies into frequency band from 100 to 1,500 Hz, hearing aid allows people to understand normal conversation, including telephone calls. Principle operation of hearing aid adapted to other uses such as, clearing up noisy telephone or radio communication. In addition, loud-speakers more easily understood in presence of high background noise.

Weinstein, Leonard M.

1994-01-01

358

Low background counting at the LBNL low background facility  

SciTech Connect

The Low Background Facility (LBF) at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to end-users in two unique facilities: locally within a carefully-constructed, low background laboratory space; and a satellite underground station (600 m.w.e) in Oroville, CA. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic and anthropogenic products, as well as active screening via neutron activation analysis for specific applications. A general overview of the facilities, services, and capabilities will be discussed. Recent activities will also be presented, including the recent installation of a 3? muon veto at the surface facility, cosmogenic activation studies of TeO{sub 2} for CUORE, and environmental monitoring of Fukushima fallout.

Thomas, K. J.; Norman, E. B. [Department of Nuclear Engineering, University of California, Berkeley, CA 94720, United States and Nuclear Science Division, Lawrence Berkeley Laboratory, CA 94720 (United States)] [Department of Nuclear Engineering, University of California, Berkeley, CA 94720, United States and Nuclear Science Division, Lawrence Berkeley Laboratory, CA 94720 (United States); Smith, A. R.; Chan, Y. D.; Hurley, D. L. [Nuclear Science Division, Lawrence Berkeley Laboratory, CA 94720 (United States)] [Nuclear Science Division, Lawrence Berkeley Laboratory, CA 94720 (United States); Wang, B. S. [Department of Nuclear Engineering, University of California, Berkeley, CA 94720 (United States)] [Department of Nuclear Engineering, University of California, Berkeley, CA 94720 (United States)

2013-08-08

359

Low background counting at the LBNL low background facility  

NASA Astrophysics Data System (ADS)

The Low Background Facility (LBF) at the Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California provides low background gamma spectroscopy services to end-users in two unique facilities: locally within a carefully-constructed, low background laboratory space; and a satellite underground station (600 m.w.e) in Oroville, CA. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic and anthropogenic products, as well as active screening via neutron activation analysis for specific applications. A general overview of the facilities, services, and capabilities will be discussed. Recent activities will also be presented, including the recent installation of a 3? muon veto at the surface facility, cosmogenic activation studies of TeO2 for CUORE, and environmental monitoring of Fukushima fallout.

Thomas, K. J.; Smith, A. R.; Chan, Y. D.; Norman, E. B.; Wang, B. S.; Hurley, D. L.

2013-08-01

360

Genetic variation in chromosomal translocation breakpoint and immune function genes and risk of non-Hodgkin lymphoma  

Microsoft Academic Search

Background  Tumor necrosis factor (TNF) and interleukin 10 (IL10) are promising candidate susceptibility genes for non-Hodgkin lymphoma (NHL). Chromosomal translocation breakpoint genes\\u000a are of interest, given their documented involvement in lymphoma progression.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  We analyzed 11 polymorphisms in BCL2, CCND1, MYC, TNF, and IL10 in a large, population-based, Danish-Swedish case–control study including 2,449 NHL cases and 1,980 controls. Relative risk\\u000a of NHL

Pia Fernberg; Ellen T. Chang; Kristina Duvefelt; Henrik Hjalgrim; Sandra Eloranta; Karina Meden Sørensen; Anna Porwit; Keith Humphreys; Mads Melbye; Karin Ekström Smedby

2010-01-01

361

Shuttling and translocation of heterotrimeric G proteins and Ras  

PubMed Central

Heterotrimeric G proteins (???) and Ras proteins are activated by cell-surface receptors that sense extracellular signals. Both sets of proteins were traditionally thought to be constrained to the plasma membrane and some intracellular membranes. Live-cell-imaging experiments have now shown that these proteins are mobile inside a cell, shuttling continually between the plasma membrane and intracellular membranes in the basal state, maintaining these proteins in dynamic equilibrium in different membrane compartments. Furthermore, on receptor activation, a family of G protein ?? subunits translocates rapidly and reversibly to the Golgi and endoplasmic reticulum enabling direct communication between the extracellular signal and intracellular membranes. A member of the Ras family has similarly been shown to translocate on activation. Although the impact of this unexpected intracellular movement of signaling proteins on cell physiology is likely to be distinct, there are striking similarities in the properties of these two families of signal-transducing proteins.

Saini, Deepak K.; Chisari, Mariangela; Gautam, N.

2011-01-01

362

Molecular dynamics study of DNA translocation through graphene nanopores  

NASA Astrophysics Data System (ADS)

A molecular dynamics simulation method is used to study the translocation of a single strand DNA through nanopores opened on graphene membranes. Simulation results uncover that the translocation time for four DNA strands (20G, 20A, 20T, and 20C) is proportional to the size of the four DNA bases. However, the change of the ionic current is caused not only by the physical blockade of the DNA, but also induced by the change of the ion distribution once the negatively charged DNA enters the nanopore. An electric double layer will be formed and causes higher cation and lower anion concentration near the DNA strand surface, which makes the ionic current blockade not sensitive to the base size for a single-layer graphene nanopore. Increasing the graphene membrane thickness can enhance the DNA physical blockage effect on ionic current and improve the nanopore sensitivity to the four DNA bases.

Li, Jiapeng; Zhang, Yan; Yang, Juekuan; Bi, Kedong; Ni, Zhonghua; Li, Deyu; Chen, Yunfei

2013-06-01

363

Finite-size scaling in unbiased translocation dynamics  

NASA Astrophysics Data System (ADS)

Finite-size scaling arguments naturally lead to the introduction of a coordinate-dependent diffusion coefficient in a Fokker–Planck description of the late-stage dynamics of unbiased polymer translocation through a membrane pore. The solution for the probability density function of the chemical coordinate matches the initial-stage subdiffusive regime and takes into account the equilibrium entropic drive. We find precise scaling relations connecting the subdiffusion exponent to the divergence with the polymer length of the translocation time, and also to the singularity of the probability density function at the absorbing boundaries. Quantitative comparisons with numerical simulation data in d = 2 strongly support the validity of the model and of the predicted scalings.

Brandani, Giovanni; Baldovin, Fulvio; Orlandini, Enzo; Stella, Attilio L.

2014-05-01

364

Variant translocations (9; 11): Identification of the critical genetic rearrangement  

SciTech Connect

The t(9;11)(p22;q23) is a recurring abnormality in acute nonlymphocytic leukemia. The analysis of complex 9;11 translocations will aid in the identification of the conserved chromosomal junction or the critical genetic alteration created by the rearrangement; however, variant translocations involving chromosomes {number sign}9 and {number sign}11 have not been reported. The authors have identified such variants in two patients who had acute myelomonocytic leukemia and acute monocytic leukemia, characterized by a t(9;11;18)(p22;q23;q12) and a t(9;11;13)(p22;q23;q34), respectively. The conserved junction resulting from these rearrangements is created by the translation of chromosomal material from 9p to 11q.

Harris, B.N.; Davis, E.M.; Le Beau, M.M.; Bitter, M.A.; Kaminer, L.S.; Rowley, J.D. (Univ. of Chicago, IL (United States)); Morgan, E. (Children's Memorial Hospital, Chicago, IL (United States))

1988-01-01

365

Regulation of Neuronal Protein Trafficking and Translocation by SUMOylation  

PubMed Central

Post-translational modifications of proteins are essential for cell function. Covalent modification by SUMO (small ubiquitin-like modifier) plays a role in multiple cell processes, including transcriptional regulation, DNA damage repair, protein localization and trafficking. Factors affecting protein localization and trafficking are particularly crucial in neurons because of their polarization, morphological complexity and functional specialization. SUMOylation has emerged as a major mediator of intranuclear and nucleo-cytoplasmic translocations of proteins involved in critical pathways such as circadian rhythm, apoptosis and protein degradation. In addition, SUMO-regulated re-localization of extranuclear proteins is required to sustain neuronal excitability and synaptic transmission. Thus, SUMOylation is a key arbiter of neuronal viability and function. Here, we provide an overview of recent advances in our understanding of regulation of neuronal protein localization and translocation by SUMO and highlight exciting areas of ongoing research.

Berndt, Anja; Wilkinson, Kevin A.; Henley, Jeremy M.

2012-01-01

366

Systematic analysis of 95 reciprocal translocations of autosomes  

Microsoft Academic Search

The statistical analysis of 95 cases of reciprocal translocations involving autosomes detected among about 10,000 patients studied with the R-banding technique gives the following information:1.An excess of break points exists for chromosome arms 4p, 9p, 10q, 21q, and 22q and a deficiency for 1p, 2p, and 6q. Furthermore, there are relatively more break points in the small arms than in

A. Aurias; M. Prieur; B. Dutrillaux; J. Lejeune

1978-01-01

367

Soft tissue tumors associated with EWSR1 translocation  

Microsoft Academic Search

The Ewing sarcoma breakpoint region 1 (EWSR1; also known as EWS) represents one of the most commonly involved genes in sarcoma translocations. In fact, it is involved in a broad variety\\u000a of mesenchymal lesions which includes Ewing's sarcoma\\/peripheral neuroectodermal tumor, desmoplastic small round cell tumor,\\u000a clear cell sarcoma, angiomatoid fibrous histiocytoma, extraskeletal myxoid chondrosarcoma, and a subset of myxoid liposarcoma.

Salvatore Romeo; Angelo P. Dei Tos

2010-01-01

368

A STOCHASTIC MODEL OF POLYMER TRANSLOCATION DYNAMICS THROUGH BIOMEMBRANES  

Microsoft Academic Search

IntroductionThe biological systems described as soft matterin mesoscopic level manifest, in contrast to hard(condensed) matter, a number of characteristics,their complexity, flexibility and fluctuations. Dueto these, there arise at physiological temperaturesa variety of conformational and dynamic transitions,which seem to be essential for biological functions.Here we investigate the stochastic dynamicsof polymer translocation through a membrane,where the fluctuations in mesoscopic...

P. J. PARK; W. SUNG

369

Respiration-driven proton translocation in micrococcus denitrificans  

Microsoft Academic Search

The polarity and stoichiometry of respiration-driven proton translocation was studied by electrometric and spectrophotometric techniques inMicrococcus denitrificans in the context of the energy transduction mechanism in bacterial oxidative phosphorylation.1.Protons are ejected through the plasma membrane during respiratory pulses and thereafter diffuse slowly back.2.In presence of ionic species mobile across the membrane (K+-valinomycin, K+-gramicidin, or SCN-), limiting?H+\\/O quotients of 8 were

Peter Scholes; Peter Mitchell

1970-01-01

370

Repetitive telomeric sequences in chromosomal translocations involving chromosome 21  

SciTech Connect

Telomeres perform key functions in maintaining chromosome integrity. In some structural rearrangements the structure and polymorphism in human telomeres may play a significant role. However, of all the telomeric and subtelomeric sequences, only the terminal TTAGGG repeats are believed essential for telomere function. During the course of a study on the role of telomere structure and polymorphism in chromosomal rearrangements observed in families referred for prenatal diagnosis, we studied three cases in which chromosome 21 was involved. Repetitive TTAGGG sequences for all human chromosomes were used as probes (Oncor). Case 1, a de novo cryptic translocation (2;21) was initially identified as monosomy 21 in a child with psychomotor delay and mild dysmorphism. Using a cosmid probe specific for region 21q22.3 and whole chromosome 21 specific painting probe, the long arm of 21 was found on the short arm of chromosome 2 with an interstitial telomere at the breakpoint junction. All the cells were monosomic for 21pter{yields}q21. Case 2 is a familial (19;21) translocation. GTG-banding and FISH with a satellite probe showed no apparent loss of material at the end of either 19q or 21q, with an interstitial telomere at the fusion site of the two intact chromosomes. In case 3, a four generation reciprocal (20;21) translocation, there was no interstitial telomere. The persistence of an interstitial telomere is a relatively rare event which can now be observed with in situ hybridization. Its study may lead to a better understanding of the dynamics of translocations and of chromosome imbalance.

Qu, J.; Dallaire, L.; Fetni, R. [Universite de Montreal, Quebec (Canada)] [and others

1994-09-01

371

Subcellular distribution and translocation of radionuclides in plants  

SciTech Connect

The subcellular distribution of radionuclides in Glycine max Merr. (soybean) and Cucumis sativus L. (cucumber) and translocation of plant absorbed radionuclides with growth in soybean were studied. More than 60% of cellular incorporated Rb{sup {minus}83}, Sr{sup {minus}85}, Mn{sup {minus}54}, Nb{sup {minus}95}, and Se{sup {minus}75} remained in the supernatant fraction; 55% and 20% of Cr{sup {minus}51} was bound to soybean and cucumber cell wall fractions, respectively; 70% or more of Be{sup {minus}7}, Y{sup {minus}88}, and Fe{sup {minus}59} was fixed in the chloroplast fraction; and approx. 10% of Sc{sup {minus}46}, Fe{sup {minus}59}, V{sup {minus}48}, and As were fixed in the mitochondrial fraction. Translocation of nuclides within the soybean plant at different stages of growth has been determined. Vanadium, Y{sup {minus}88}, Be{sup {minus}7}, Se{sup {minus}75}, Nb{sup {minus}95}, Sc{sup {minus}46}, Cr{sup {minus}51}, and Zr{sup {minus}88} were predominantly accumulated in the root. Although the total percentage of plant uptake of Sc{sup {minus}46}, Zr{sup {minus}88}, Nb{sup {minus}95}, Sc{sup {minus}46}, and Cr{sup {minus}51} was high, because of low mobility and translocation to shoot, their accumulation in the fruit fraction was negligible. The translocation of mobile nuclides in plants was demonstrated clearly by Rb{sup {minus}83}, Zn{sup {minus}65}, and Fe{sup {minus}59}. Data on the nuclide fraction mobilized from vegetative parts into edible parts was used to assess the percentage of accumulated radionuclides in plants that may reach humans through beans.

Gouthu, S.; Weginwar, R.; Arie, Tsutomu; Ambe, Shizuko; Ozaki, Takuo; Enomoto, Shuichi; Ambe, Fumitoshi; Yamaguchi, Isamu

1999-09-01

372

DNA translocating through a carbon nanotube can increase ionic current.  

PubMed

Translocation of DNA through a narrow, single-walled carbon nanotube can be accompanied by large increases in ion current, recently observed in contrast to the ion current blockade. We use molecular dynamics simulations to show that large electro-osmotic flow can be turned into a large net current via ion-selective filtering by a DNA molecule inside the carbon nanotube. PMID:23090315

Park, Jae Hyun; He, Jin; Gyarfas, Brett; Lindsay, Stuart; Krsti?, Predrag S

2012-11-16

373

Poison domains block transit of translocated substrates via the Legionella pneumophila Icm/Dot system.  

PubMed

Legionella pneumophila uses the Icm/Dot type 4B secretion system (T4BSS) to deliver translocated protein substrates to the host cell, promoting replication vacuole formation. The conformational state of the translocated substrates within the bacterial cell is unknown, so we sought to determine if folded substrates could be translocated via this system. Fusions of L. pneumophila Icm/Dot-translocated substrates (IDTS) to dihydrofolate reductase (DHFR) or ubiquitin (Ub), small proteins known to fold rapidly, resulted in proteins with low translocation efficiencies. The folded moieties did not cause increased aggregation of the IDTS and did not impede interaction with the adaptor protein complex IcmS/IcmW, which is thought to form a soluble complex that promotes translocation. The translocation defect was alleviated with a Ub moiety harboring mutations known to destabilize its structure, indicating that unfolded proteins are preferred substrates. Real-time analysis of translocation, following movement during the first 30 min after bacterial contact with host cells, revealed that the folded moiety caused a kinetic defect in IDTS translocation. Expression of an IDTS fused to a folded moiety interfered with the translocation of other IDTS, consistent with it causing a blockage of the translocation channel. Furthermore, the folded protein fusions also interfered with intracellular growth, consistent with inefficient or impaired translocation of proteins critical for L. pneumophila intracellular growth. These studies indicate that substrates of the Icm/Dot T4SS are translocated to the host cytosol in an unfolded conformation and that folded proteins are stalled within the translocation channel, impairing the function of the secretion system. PMID:23798536

Amyot, Whitney M; deJesus, Dennise; Isberg, Ralph R

2013-09-01

374

Poison Domains Block Transit of Translocated Substrates via the Legionella pneumophila Icm/Dot System  

PubMed Central

Legionella pneumophila uses the Icm/Dot type 4B secretion system (T4BSS) to deliver translocated protein substrates to the host cell, promoting replication vacuole formation. The conformational state of the translocated substrates within the bacterial cell is unknown, so we sought to determine if folded substrates could be translocated via this system. Fusions of L. pneumophila Icm/Dot-translocated substrates (IDTS) to dihydrofolate reductase (DHFR) or ubiquitin (Ub), small proteins known to fold rapidly, resulted in proteins with low translocation efficiencies. The folded moieties did not cause increased aggregation of the IDTS and did not impede interaction with the adaptor protein complex IcmS/IcmW, which is thought to form a soluble complex that promotes translocation. The translocation defect was alleviated with a Ub moiety harboring mutations known to destabilize its structure, indicating that unfolded proteins are preferred substrates. Real-time analysis of translocation, following movement during the first 30 min after bacterial contact with host cells, revealed that the folded moiety caused a kinetic defect in IDTS translocation. Expression of an IDTS fused to a folded moiety interfered with the translocation of other IDTS, consistent with it causing a blockage of the translocation channel. Furthermore, the folded protein fusions also interfered with intracellular growth, consistent with inefficient or impaired translocation of proteins critical for L. pneumophila intracellular growth. These studies indicate that substrates of the Icm/Dot T4SS are translocated to the host cytosol in an unfolded conformation and that folded proteins are stalled within the translocation channel, impairing the function of the secretion system.

Amyot, Whitney M.; deJesus, Dennise

2013-01-01

375

Single Strand DNA Molecules Translocation through Nanoelectrode Gaps  

SciTech Connect

Molecular dynamics simulations were performed to investigate the translocation of single-strand DNA through nanoscale electrode gaps under the action of a constant driving force. The application behind this theoretical study is a proposal to use nanoelectrodes as a screening gap as part of a rapid genomic sequencing device. Preliminary results from a series of simulations using various gap widths and driving forces suggest that the narrowest electrode gap that a single-strand DNA can pass is {approx}1.5 nm. The minimum force required to initiate the translocation within nanoseconds is {approx}0.3 nN. Simulations using DNA segments of various lengths indicate that the minimum initiation force is insensitive to the length of DNA. However, the average threading velocity of DNA varies appreciably from short to long DNA segments. We attribute such variation to the different nature of drag force experienced by the short and long DNA segments in the environment. It is found that DNA molecules deform significantly to fit in the shape of the nanogap during the translocation

Lee, James Weifu [ORNL; Zhao, Xiongce [ORNL; Cummings, Peter T [ORNL

2007-01-01

376

Coliphage HK022 Nun protein inhibits RNA polymerase translocation.  

PubMed

The Nun protein of coliphage HK022 arrests RNA polymerase (RNAP) in vivo and in vitro at pause sites distal to phage ? N-Utilization (nut) site RNA sequences. We tested the activity of Nun on ternary elongation complexes (TECs) assembled with templates lacking the ? nut sequence. We report that Nun stabilizes both translocation states of RNAP by restricting lateral movement of TEC along the DNA register. When Nun stabilized TEC in a pretranslocated register, immediately after NMP incorporation, it prevented binding of the next NTP and stimulated pyrophosphorolysis of the nascent transcript. In contrast, stabilization of TEC by Nun in a posttranslocated register allowed NTP binding and nucleotidyl transfer but inhibited pyrophosphorolysis and the next round of forward translocation. Nun binding to and action on the TEC requires a 9-bp RNA-DNA hybrid. We observed a Nun-dependent toe print upstream to the TEC. In addition, mutations in the RNAP ?' subunit near the upstream end of the transcription bubble suppress Nun binding and arrest. These results suggest that Nun interacts with RNAP near the 5' edge of the RNA-DNA hybrid. By stabilizing translocation states through restriction of TEC lateral mobility, Nun represents a novel class of transcription arrest factors. PMID:24853501

Vitiello, Christal L; Kireeva, Maria L; Lubkowska, Lucyna; Kashlev, Mikhail; Gottesman, Max

2014-06-10

377

Detection of Kinase Translocation Using Microfluidic Electroporative Flow Cytometry  

NASA Astrophysics Data System (ADS)

Translocation of a protein between different subcellular compartments is a common event during signal transduction in living cells. Detection of these events has been largely carried out based on imaging of a low number of cells and subcellular fractionation/Western blotting. These conventional techniques either lack the high throughput desired for probing an entire cell population or provide only the average behaviors of cell populations without information from single cells. Here we demonstrate a new tool, referred to as microfluidic electroporative flow cytometry, to detect the translocation of an EGFP-tagged tyrosine kinase, Syk, to the plasma membrane in B cells at the level of the cell population. We combine electroporation with flow cytometry and observe the release of intracellular kinase out of the cells during electroporation. We found that the release of the kinase was strongly influenced by its subcellular localization. Cells stimulated through the antigen receptor have a fraction of the kinase at the plasma membrane and retain more kinase after electroporation than do cells without stimulation and translocation. This tool will have utility for kinase-related drug discovery and tumor diagnosis and staging.

Lu, Chang; Wang, Jun; Bao, Ning; Paris, Leela; Wang, Hsiang-Yu; Geahlen, Robert

2008-03-01

378

C- to N-terminal translocation of preproteins into mitochondria.  

PubMed Central

Nuclear-encoded mitochondrial matrix proteins in most cases contain N-terminal targeting signals and are imported in a linear N- to C-terminal (N-->C) fashion. We asked whether import can also occur in a C- to N-terminal direction (C-->N). We placed targeting signals at the C-terminus of passenger proteins. Import did occur in this 'backwards' fashion. It paralleled that of the 'normal' N-->C mechanism in terms of efficiency, rate, energetic requirements and ability to mediate unfolding and refolding during and following import of protein containing a folded domain. Furthermore, this reaction was mediated by the TIM17-23 machinery. The import pathway taken by certain inner-membrane proteins contains elements of such a C-->N translocation pathway, as they are targeted to mitochondria by internal targeting signals. These internal targeting signals appear to form loop structures together with neighbouring transmembrane segments, and penetrate the inner membrane in a membrane-potential-dependent manner. The dimeric TIM17-23 complex, together with mt-Hsp70, acts on both sides of the loop structure to facilitate their translocation into the matrix. On one side of the loop import occurs in the common N-->C direction, whereas the translocation of the other side involves the novel C-->N import direction. We conclude therefore that the mitochondrial import machinery displays no preference for the directionality of the import process.

Folsch, H; Gaume, B; Brunner, M; Neupert, W; Stuart, R A

1998-01-01

379

Twin-arginine-dependent translocation of folded proteins  

PubMed Central

Twin-arginine translocation (Tat) denotes a protein transport pathway in bacteria, archaea and plant chloroplasts, which is specific for precursor proteins harbouring a characteristic twin-arginine pair in their signal sequences. Many Tat substrates receive cofactors and fold prior to translocation. For a subset of them, proofreading chaperones coordinate maturation and membrane-targeting. Tat translocases comprise two kinds of membrane proteins, a hexahelical TatC-type protein and one or two members of the single-spanning TatA protein family, called TatA and TatB. TatC- and TatA-type proteins form homo- and hetero-oligomeric complexes. The subunits of TatABC translocases are predominantly recovered from two separate complexes, a TatBC complex that might contain some TatA, and a homomeric TatA complex. TatB and TatC coordinately recognize twin-arginine signal peptides and accommodate them in membrane-embedded binding pockets. Advanced binding of the signal sequence to the Tat translocase requires the proton-motive force (PMF) across the membranes and might involve a first recruitment of TatA. When targeted in this manner, folded twin-arginine precursors induce homo-oligomerization of TatB and TatA. Ultimately, this leads to the formation of a transmembrane protein conduit that possibly consists of a pore-like TatA structure. The translocation step again is dependent on the PMF.

Frobel, Julia; Rose, Patrick; Muller, Matthias

2012-01-01

380

Compositions and methods for detecting gene rearrangements and translocations  

DOEpatents

Disclosed is a series of nucleic acid probes for use in diagnosing and monitoring certain types of leukemia using, e.g., Southern and Northern blot analyses and fluorescence in situ hybridization (FISH). These probes detect rearrangements, such as translocations involving chromosome band 11q23 with other chromosomes bands, including 4q21, 6q27, 9p22, 19p13.3, in both dividing leukemic cells and interphase nuclei. The breakpoints in all such translocations are clustered within an 8.3 kb BamHI genomic region of the MLL gene. A novel 0.7 kb BamH1 cDNA fragment derived from this gene detects rearrangements on Southern blot analysis with a single BamHI restriction digest in all patients with the common 11q23 translocations and in patients with other 11q23 anomalies. Northern blot analyses are presented demonstrating that the MLL gene has multiple transcripts and that transcript size differentiates leukemic cells from normal cells. Also disclosed are MLL fusion proteins, MLL protein domains and anti-MLL antibodies.

Rowley, Janet D. (Chicago, IL); Diaz, Manuel O. (Chicago, IL)

2000-01-01

381

Muscular dystrophy in girls with X;autosome translocations.  

PubMed

Twenty known cases of X;autosome translocations with breakpoints at Xp21 associated with Duchenne or Becker muscular dystrophy in girls are reviewed. The variable severity described for different persons may reflect differences in X inactivation or in the nature of the genomic target disrupted. High resolution cytogenetic studies on 12 cases indicate breakpoints on the X chromosome at Xp21.1 or Xp21.2. Translocation chromosomes from several of these cases have been isolated in human/mouse somatic cell hybrids. Molecular heterogeneity in the breakpoint positions has been established by probing DNA from these hybrids with a range of cloned sequences known to be located within, or closely linked to, the Duchenne region. The minimum separation between the most distal and the most proximal breakpoints is 176 kb suggesting that, if a single gene is involved, it must be large. Alternatively, the translocations may affect different genes, or confer alterations to regulatory sequences which operate at a distance. PMID:3806636

Boyd, Y; Buckle, V; Holt, S; Munro, E; Hunter, D; Craig, I

1986-12-01

382

Impacts of Neuroscience: Background Paper.  

National Technical Information Service (NTIS)

The background paper surveys the scientific basis of research on the nervous system, identifies several medical applications, examines some of the social effects, and discusses some of the difficult ethical and political issues that may arise from discove...

1984-01-01

383

US ITER background summary papers.  

National Technical Information Service (NTIS)

The following brief summaries were prepared by members of the US ITER Home Team to provide background information on the ITER CDA design and in several instances to provide personal observations and suggestions regarding continuation of the ITER Conceptua...

J. N. Doggett C. A. Flanagan D. E. Post J. C. Wesley

1991-01-01

384

Characterisation of Background Biological Aerosol.  

National Technical Information Service (NTIS)

Sampling of ambient air using a glass cyclone system for fluorescence background determination is described. Weekly samples over 12 hour sampling periods are taken at the University College Galway 5 atmospheric research field station at Mace Head, on the ...

S. G. Jennings C. M. Kenny

1997-01-01

385

Nongeometric fluxes as supergravity backgrounds  

NASA Astrophysics Data System (ADS)

We consider examples of D=4 string theory vacua which, although globally nongeometric, admit a local description in terms of D=10 supergravity backgrounds. We analyze such backgrounds and find that the supersymmetry spinors vary nontrivially along the internal manifold, reproducing the interpolating supergravity solutions found by Frey and Graña. Finally, we propose a simple, local expression for nongeometric fluxes in terms of the internal spinors of the compactification.

Marchesano, Fernando; Schulgin, Waldemar

2007-08-01

386

Nongeometric fluxes as supergravity backgrounds  

SciTech Connect

We consider examples of D=4 string theory vacua which, although globally nongeometric, admit a local description in terms of D=10 supergravity backgrounds. We analyze such backgrounds and find that the supersymmetry spinors vary nontrivially along the internal manifold, reproducing the interpolating supergravity solutions found by Frey and Grana. Finally, we propose a simple, local expression for nongeometric fluxes in terms of the internal spinors of the compactification.

Marchesano, Fernando [ASC, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Schulgin, Waldemar [Max Planck Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany)

2007-08-15

387

Unbalanced translocation in a mother and her son in one of two 5;10 translocation families  

SciTech Connect

We present two families with different distal long arm 5;10 translocations. In one family the propositus and his mother inherited the same derived chromosome 10 from the maternal grandfather who has a balanced t(5;10)(q35.3;q26.13). The phenotype of both the affected patients is milder and only partially overlaps with that of previous cases of distal 10q deletion. Other previously reported cases of transmitted imbalance are also remarkable for mild phenotype, occurrence of deletions rather than duplications and a strong bias toward maternal as opposed to paternal transmission. In the second family, the propositus inherited a derived chromosome 10 from his mother who carries a balanced t(5;10)(q35.1;q26.3) translocation; his clinical manifestations are consistent with an emerging phenotype for distal 5q duplications. 30 refs., 6 figs., 2 tabs.

John, C.K.; Barber, I.; Collinson, M.N. [Salisbury District Hospital (United Kingdom)] [and others

1996-03-01

388

Molecular breakpoint cloning and gene expression studies of a novel translocation t(4;15)(q27;q11.2) associated with Prader-Willi syndrome  

Microsoft Academic Search

BACKGROUND: Prader-Willi syndrome (MIM #176270; PWS) is caused by lack of the paternally-derived copies, or their expression, of multiple genes in a 4 Mb region on chromosome 15q11.2. Known mechanisms include large deletions, maternal uniparental disomy or mutations involving the imprinting center. De novo balanced reciprocal translocations in 5 reported individuals had breakpoints clustering in SNRPN intron 2 or exon

Birgitt Schüle; Mohammed Albalwi; Emma Northrop; David I Francis; Margaret Rowell; Howard R Slater; RJ McKinlay Gardner; Uta Francke

2005-01-01

389

Adenosine Transporter ENT4 Is a Direct Target of EWS\\/WT1 Translocation Product and Is Highly Expressed in Desmoplastic Small Round Cell Tumor  

Microsoft Academic Search

BackgroundDesmoplastic Small Round Cell Tumor (DSRCT) is a highly aggressive malignancy that affects mainly adolescents and young adults. A defining characteristic of DSRCT is a specific chromosomal translocation, t(11;22)(p13;q12), that fuses EWS with WT1, leading to a production of two isoforms of chimeric transcription factor, EWS\\/WT1(?KTS) and EWS\\/WT1(+KTS). The chimeric proteins are thought to play critical roles in various stages

Hongjie Li; Gromoslaw A. Smolen; Lisa F. Beers; Li Xia; William Gerald; Joanne Wang; Daniel A. Haber; Sean Bong Lee; Dong-Yan Jin

2008-01-01

390

Antibiotics that bind to the A site of the large ribosomal subunit can induce mRNA translocation.  

PubMed

In the absence of elongation factor EF-G, ribosomes undergo spontaneous, thermally driven fluctuation between the pre-translocation (classical) and intermediate (hybrid) states of translocation. These fluctuations do not result in productive mRNA translocation. Extending previous findings that the antibiotic sparsomycin induces translocation, we identify additional peptidyl transferase inhibitors that trigger productive mRNA translocation. We find that antibiotics that bind the peptidyl transferase A site induce mRNA translocation, whereas those that do not occupy the A site fail to induce translocation. Using single-molecule FRET, we show that translocation-inducing antibiotics do not accelerate intersubunit rotation, but act solely by converting the intrinsic, thermally driven dynamics of the ribosome into translocation. Our results support the idea that the ribosome is a Brownian ratchet machine, whose intrinsic dynamics can be rectified into unidirectional translocation by ligand binding. PMID:23249745

Ermolenko, Dmitri N; Cornish, Peter V; Ha, Taekjip; Noller, Harry F

2013-02-01

391

Mitochondrial translocation of cofilin is required for allyl isothiocyanate-mediated cell death via ROCK1/PTEN/PI3K signaling pathway  

PubMed Central

Background Cofilin is a member of the actin depolymerizing factor (ADF)/cofilin family, which regulates actin dynamics. Increasing evidence suggests that mitochondrial translocation of cofilin appears necessary for the regulation of apoptosis. Results We report that allyl isothiocyanate (AITC) potently induces mitochondria injury and apoptosis. These events were accompanied by a loss of polymerized filamentous actin (F-actin) and increase in unpolymerized globular actin (G-actin). AITC also induces dephosphorylation of cofilin through activation of PP1 and PP2A. Only dephosphorylated cofilin binds to G-actin and translocates to mitochondria during AITC-mediated apoptosis. Mechanistic study revealed that interruption of ROCK1/PTEN/PI3K signaling pathway plays a critical role in AITC-mediated dephosphorylation and mitochondrial translocation of cofilin and apoptosis. Our in vivo study also showed that AITC-mediated inhibition of tumor growth of mouse leukemia xenograft model is in association with dephosphorylation of cofilin. Conclusions These findings support a model in which induction of apoptosis by AITC stems primarily from activation of ROCK1 and PTEN, and inactivation of PI3K, leading in turn to activation of PP1 and PP2A, resulting in dephosphorylation of cofilin, which binds to G-actin and translocates to mitochondria, culminating in the dysfunction of mitochondria, release of cytochrome c and apoptosis.

2013-01-01

392

Induction of Chromosomal Translocations in Mouse and Human Cells Using Site-Specific Endonucleases  

PubMed Central

Reciprocal chromosomal translocations are early and essential events in the malignant transformation of several tumor types, yet the precise mechanisms that mediate translocation formation are poorly understood. We review here the development of approaches to induce and recover translocations between two targeted DNA double-strand breaks (DSBs) in mammalian chromosomes. Using mouse cells, we find that nonhomologous end-joining readily mediates translocation formation between two DSBs generated by site-specific endonucleases. Translocations occur much less frequently, however, than intrachromosomal repair of a single DSB. Translocation junctions obtained with this approach have similar end modifications to translocation junctions found in human tumors, including deletions, insertions, and repair at short stretches of homology. These modifications are more extensive than repair junctions at a single DSB, suggesting that different factors may be involved in translocation formation and repair of a single DSB. Finally, we describe a novel approach to induce translocations in human cells. Translocation model systems provide an opportunity to study the involvement of mammalian DNA repair and signaling factors in the etiology of chromosomal rearrangements.

Weinstock, David M.; Brunet, Erika; Jasin, Maria

2012-01-01

393

Fitness costs of neighborhood disruption in translocations of a solitary mammal.  

PubMed

Translocation is used to reestablish wild populations of animals, but translocation projects often do not meet their objectives because postrelease mortality of animals is high. One reason for translocation failure is that the behavioral or ecological requirements of released animals are unmet. Maintaining founder-group social relationships during release can affect reestablishment of social species. Solitary territorial species with stable neighbors (restricted dispersal and lifetime occupation of a home range) of the same species may also benefit from the maintenance of these social relationships during translocation. We translocated Stephens' kangaroo rats (Dipodomys stephensi), a solitary species listed as endangered under the U.S. Endangered Species Act, with and without neighboring kangaroo rats. We compared the settlement (establishment of a stable home range) decisions and fitness of kangaroo rats between the 2 treatments. Kangaroo rats translocated with neighbors traveled shorter distances before establishing territories, had higher survival rates, and had significantly higher reproductive success than kangaroo rats translocated without neighbors. Number of offspring was 24-fold higher for kangaroo rats translocated with neighbors than those translocated without neighbors. Differences in behavior following release may partially explain differences in survival between the 2 groups. Immediately following release, animals translocated with neighbors fought less and spent significantly more time foraging and digging burrows than animals translocated without neighbors. Our results indicate that even for solitary species, maintaining relationships among members of a translocated group of animals can influence translocation success. This study is the first empirical demonstration of the fitness consequences of disrupting social relationships among territorial neighbors. PMID:21978094

Shier, Debra M; Swaisgood, Ronald R

2012-02-01

394

Task-Dependent and Independent Synchronous Activity of Monkey Hippocampal Neurons in Real and Virtual Translocation  

PubMed Central

Previous neurophysiological and behavioral studies relate hippocampal functions to place learning and memory, and encoding of task (or context)-specific information. Encoding of both task-specific information and own location is essential for episodic memory and for animals to navigate to reward-related places. It is suggested that different neural circuits with different assemblies of different hippocampal neurons are created in different environments or behavioral contexts for the hippocampal formation (HF) to encode and retrieve episodic memory. To investigate whether synchronous activity of hippocampal neurons, suggesting functional connectivity between those neurons, is task and position dependent, multiple single unit activities were recorded during performance of real and virtual translocation (VT) tasks. The monkey moved to one of four reward areas by driving a cab (real translocation) or by moving a pointer on a monitor. Of 163 neuron pairs, significant peaks in cross-correlograms (CCGs) were observed in 98 pairs. Most CCGs had positive peaks within 50?ms. Task-dependent cross-correlations (CCRs) were observed in 44% of the neuron pairs, and similarly observed in both the real and VT tasks. These CCRs were frequently observed in pyramidal vs. pyramidal neuron pairs with positive peak and peak shift. However, no consistent patterns of peak polarity, peak shift, and neuronal types were seen in task-independent CCRs. There was no significant difference in frequency of CCG peaks between real and VT tasks. These results suggest that the task-dependent information may be encoded by interaction among pyramidal neurons, and the common information across tasks may be encoded by interaction among pyramidal neurons and interneurons in the HF. These neuronal populations could provide a neural basis for episodic memory to disambiguously guide animals to places associated with reward in different situations.

Hori, Etsuro; Tabuchi, Eiichi; Matsumura, Nobuhisa; Ono, Taketoshi; Nishijo, Hisao

2011-01-01

395

Voltage-Driven Translocation of DNA through a High Throughput Conical Solid-State Nanopore  

PubMed Central

Nanopores have become an important tool for molecule detection at single molecular level. With the development of fabrication technology, synthesized solid-state membranes are promising candidate substrates in respect of their exceptional robustness and controllable size and shape. Here, a 30–60 (tip-base) nm conical nanopore fabricated in 100 nm thick silicon nitride (Si3N4) membrane by focused ion beam (FIB) has been employed for the analysis of ?-DNA translocations at different voltage biases from 200 to 450 mV. The distributions of translocation time and current blockage, as well as the events frequencies as a function of voltage are investigated. Similar to previously published work, the presence and configurations of ?-DNA molecules are characterized, also, we find that greater applied voltages markedly increase the events rate, and stretch the coiled ?-DNA molecules into linear form. However, compared to 6–30 nm ultrathin solid-state nanopores, a threshold voltage of 181 mV is found to be necessary to drive DNA molecules through the nanopore due to conical shape and length of the pore. The speed is slowed down ?5 times, while the capture radius is ?2 fold larger. The results show that the large nanopore in thick membrane with an improved stability and throughput also has the ability to detect the molecules at a single molecular level, as well as slows down the velocity of molecules passing through the pore. This work will provide more motivations for the development of nanopores as a Multi-functional sensor for a wide range of biopolymers and nano materials.

Liu, Quanjun; Wu, Hongwen; Wu, Lingzhi; Xie, Xiao; Kong, Jinglin; Ye, Xiaofeng; Liu, Liping

2012-01-01

396

Background simulations and shielding calculations  

SciTech Connect

Key improvements in the sensitivity of the underground particle astrophysics experiments can only be achieved if the radiation causing background events in detectors is well understood and proper measures are taken to suppress it. The background radiation arising from radioactivity and cosmic-ray muons is discussed here together with the methods of its suppression. Different shielding designs are considered to attenuate gamma-rays and neutrons coming from radioactivity in rock and lab walls. Purity of materials used in detector construction is analysed and the background event rates due to the presence of radioactive isotopes in detector components are discussed. Event rates in detectors caused by muon-induced neutrons with and without active veto systems are presented leading to the requirements for the depth of an underground laboratory and the efficiency of the veto system.

Kudryavtsev, Vitaly A. [Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH (United Kingdom)

2011-04-27

397

Exotic branes and nongeometric backgrounds.  

PubMed

When string or M theory is compactified to lower dimensions, the U-duality symmetry predicts so-called exotic branes whose higher-dimensional origin cannot be explained by the standard string or M-theory branes. We argue that exotic branes can be understood in higher dimensions as nongeometric backgrounds or U folds, and that they are important for the physics of systems which originally contain no exotic charges, since the supertube effect generically produces such exotic charges. We discuss the implications of exotic backgrounds for black hole microstate (non-)geometries. PMID:20867363

de Boer, Jan; Shigemori, Masaki

2010-06-25

398

Detector Background at Muon Colliders  

SciTech Connect

Physics goals of a Muon Collider (MC) can only be reached with appropriate design of the ring, interaction region (IR), high-field superconducting magnets, machine-detector interface (MDI) and detector. Results of the most recent realistic simulation studies are presented for a 1.5-TeV MC. It is shown that appropriately designed IR and MDI with sophisticated shielding in the detector have a potential to substantially suppress the background rates in the MC detector. The main characteristics of backgrounds are studied.

Mokhov, N.V.; Striganov, S.I.; /Fermilab

2011-09-01

399

HMGB1 neutralization is associated with bacterial translocation during acetaminophen hepatotoxicity  

PubMed Central

Background Acetaminophen (APAP) hepatotoxicity is associated with a high rate of gram-negative enteric bacterial infection; however, the underlying mechanism is still unknown. APAP overdose induces massive hepatocyte necrosis, necrotic tissue releases high mobility group B1 (HMGB1) and exogenous HMGB1 is able to induce gut bacterial translocation (BT) in normal mice; therefore, it is possible that HMGB1 mediates gut BT in APAP hepatotoxicity. This study aims to test this hypothesis by using anti-HMGB1 neutralizing antibody to treat APAP overdose for 24-48 hours. Methods Male C57BL/6 mice were intraperitoneally (i.p.) injected with a single dose of APAP (350 mg/kg dissolved in 1 mL sterile saline). 2 hrs after APAP injection, the APAP challenged mice were randomized to receive treatment with either anti-HMGB1 antibody (400 ?g per dose) or non-immune (sham) IgG every 24 h for a total of 2 doses. Results 24 and 48 hrs after APAP challenge, anti-HMGB1 treatment instead of sham IgG therapy significantly decreased serum HMGB1 concentrations and reduced BT by 85%; serum HMGB1 levels were positively correlated with the amount of BT; anti-HMGB1 therapy decreased hepatic BT at 48 h, which was associated with better recovered liver structure and better restored hepatic immune system that was shown by enhanced hepatic mRNA expression of TNF-?, IL-6 and extensive proliferation of inflammatory and reticuloendothelial cells; however, anti-HMGB1 treatment did not decrease gut mucosal permeability as compared to the sham IgG therapy at either 24 or 48 hrs. Conclusion HMGB1 neutralization is associated with bacterial translocation during APAP hepatotoxicity.

2014-01-01

400

Aquaporin-1 Translocation and Degradation Mediates the Water Transportation Mechanism of Acetazolamide  

PubMed Central

Background Diuretic agents are widely used on the treatment of water retention related diseases, among which acetazolamide (AZA) acts originally as a carbonic anhydrase (CA) inhibitor. Aquaporin-1 (AQP1) being located in renal proximal tubules is required for urine concentration. Previously our lab has reported AZA putatively modulated AQP1. Aim of this study is to testify our hypothesis that regulating AQP1 may mediate diuretic effect of AZA. Methodology/Principal Findings For in vivo study, we utilized Sprague Dawley rats, as well as AQP1 knock-out (AQP1?/?) mice to examine urine volume, and human kidney-2 (HK-2) cell line was used for in vitro mechanism study. In our present study we found that AZA decreased CAs activity initially but the activity gradually recovered. Contrarily, diuretic effect was consistently significant. AQP1 protein expression was significantly decreased on day 7 and 14. By utilizing AQP1?/? mice, we found diuretic effect of AZA was cancelled on day 14, while urine volume continuously increased in wild-type mice. Surface plasmon resonance (SPR) results indicated AQP1 was physiologically bound by myosin heavy chain (MHC), immunoprecipitation and immunofluorescence results confirmed this protein interaction. In vitro study results proved AZA facilitated AQP1 translocation onto cell membrane by promoting interaction with MHC, dependent on ERK/ myosin light chain kinase (MLCK) pathway activation. MHC inhibitor BDM and ERK inhibitor U0126 both abolished above effect of AZA. Eventually AZA induced AQP1 ubiquitination, while proteasome inhibitor MG132 reversed AZA's down-regulating effect upon AQP1. Conclusions/Significance Our results identified AZA exerted diuretic effect through an innovative mechanism by regulating AQP1 and verified its inhibitory mechanism was via promoting MHC-dependent translocation onto cell membrane and then ubiquitin mediated degradation, implicating a novel mechanism and target for diuretic agent discovering.

Gao, Junwei; Han, Jing; Pan, Xueyang; Pan, Yan; Tie, Lu; Li, Xuejun

2012-01-01

401

Effects of infliximab on bacterial translocation in experimental acute necrotizing pancreatitis  

PubMed Central

Background & objectives: Translocation of bacteria from the gut is an important factor in the development of septic complications and mortality in acute pancreatitis (AP). The present study was designed to assess the effects of infliximab treatment on bacterial translocation (BT) in experimental acute necrotizing pancreatitis. Methods: Male Sprague-Dawley rats (n=45) were allocated into three groups. AP was induced in group II (positive control, n=15) and group III (Infliximab; n=15) by retrograde injection of taurocholate into the common biliopancreatic duct. Group I rats (Sham; n=15) received normal saline infusion into the common biliopancreatic duct as placebo. Groups I and II were treated by normal saline and group III was treated with infliximab intraperitoneally on 6, 30 and 54 h after induction of pancreatitis. All surviving animals were killed 60 h after the induction of pancreatitis, and specimens were collected for amylase measurement as well as histopathologic and microbiologic examinations. Results: Oedema, acinar cell necrosis, inflammatory infiltration, haemorrhage, fat necrosis and perivascular inflammation in group III rats were decreased with infliximab treatment when compared with group II (P<0.001). BT to mesentery lymph node in groups I, II and III were 20, 100 and 46 per cent, respectively. BT to peritoneum and pancreas in group III was lower than group II (P<0.05). Interpretation & conclusions: Infliximab administration resulted in beneficial effects on BT and histopathologic changes in the experimental necrotizing pancreatitis. Whether anti-TNF therapy has a role in prevention of complications of ANP needs to be established.

Aydin, Sezai; Isik, A. Turan; Unal, Bulent; Comert, Bilgin; Ozyurt, Mustafa; Deveci, Salih; Ozgur, Gokhan; Cengiz, Omer; Tasci, Ilker; Mas, M. Refik

2012-01-01

402

Tyrosine kinase chromosomal translocations mediate distinct and overlapping gene regulation events  

PubMed Central

Background Leukemia is a heterogeneous disease commonly associated with recurrent chromosomal translocations that involve tyrosine kinases including BCR-ABL, TEL-PDGFRB and TEL-JAK2. Most studies on the activated tyrosine kinases have focused on proximal signaling events, but little is known about gene transcription regulated by these fusions. Methods Oligonucleotide microarray was performed to compare mRNA changes attributable to BCR-ABL, TEL-PDGFRB and TEL-JAK2 after 1 week of activation of each fusion in Ba/F3 cell lines. Imatinib was used to control the activation of BCR-ABL and TEL-PDGFRB, and TEL-JAK2-mediated gene expression was examined 1 week after Ba/F3-TEL-JAK2 cells were switched to factor-independent conditions. Results Microarray analysis revealed between 800 to 2000 genes induced or suppressed by two-fold or greater by each tyrosine kinase, with a subset of these genes commonly induced or suppressed among the three fusions. Validation by Quantitative PCR confirmed that eight genes (Dok2, Mrvi1, Isg20, Id1, gp49b, Cxcl10, Scinderin, and collagen V?1(Col5a1)) displayed an overlapping regulation among the three tested fusion proteins. Stat1 and Gbp1 were induced uniquely by TEL-PDGFRB. Conclusions Our results suggest that BCR-ABL, TEL-PDGFRB and TEL-JAK2 regulate distinct and overlapping gene transcription profiles. Many of the genes identified are known to be involved in processes associated with leukemogenesis, including cell migration, proliferation and differentiation. This study offers the basis for further work that could lead to an understanding of the specificity of diseases caused by these three chromosomal translocations.

2011-01-01

403

Serotonin transporter (SERT) and translocator protein (TSPO) expression in the obese ob/ob mouse  

PubMed Central

Background An ever growing body of evidences is emerging concerning metabolism hormones, neurotransmitters or stress-related biomarkers as effective modulators of eating behavior and body weight in mammals. The present study sought at examining the density and affinity of two proteins related to neurotransmission and cell metabolism, the serotonin transporter SERT and the cholesterol import-benzodiazepine site TSPO (translocator protein), in a rodent leptin-lacking mutant, the obese ob/ob mouse. Binding studies were thus carried out in brain or peripheral tissues, blood platelets (SERT) and kidneys (TSPO), of ob/ob and WT mice supplied with a standard diet, using the selective radiochemical ligands [3H]-paroxetine and [3H]-PK11195. Results We observed comparable SERT number or affinity in brain and platelets of ob/ob and WT mice, whilst a significantly higher [3H]-PK11195 density was reported in the brain of ob/ob animals. TSPO binding parameters were similar in the kidneys of all tested mice. By [3H]-PK11195 autoradiography of coronal hypothalamic-hippocampal sections, an increased TSPO signal was detected in the dentate gyrus (hippocampus) and choroids plexus of ob/ob mice, without appreciable changes in the cortex or hypothalamic-thalamic regions. Conclusions These findings show that TSPO expression is up-regulated in cerebral regions of ob/ob leptin-deficient mice, suggesting a role of the translocator protein in leptin-dependent CNS trophism and metabolism. Unchanged SERT in mutant mice is discussed herein in the context of previous literature as the forerunner to a deeper biochemical investigation.

2011-01-01

404

Stabilization of Dicentric Translocations through Secondary Rearrangements Mediated by Multiple Mechanisms in S. cerevisiae  

PubMed Central

Background The gross chromosomal rearrangements (GCRs) observed in S. cerevisiae mutants with increased rates of accumulating GCRs include predicted dicentric GCRs such as translocations, chromosome fusions and isoduplications. These GCRs resemble the genome rearrangements found as mutations underlying inherited diseases as well as in the karyotypes of many cancers exhibiting ongoing genome instability Methodology/Principal Findings The structures of predicted dicentric GCRs were analyzed using multiple strategies including array-comparative genomic hybridization, pulse field gel electrophoresis, PCR amplification of predicted breakpoints and sequencing. The dicentric GCRs were found to be unstable and to have undergone secondary rearrangements to produce stable monocentric GCRs. The types of secondary rearrangements observed included: non-homologous end joining (NHEJ)-dependent intramolecular deletion of centromeres; chromosome breakage followed by NHEJ-mediated circularization or broken-end fusion to another chromosome telomere; and homologous recombination (HR)-dependent non-reciprocal translocations apparently mediated by break-induced replication. A number of these GCRs appeared to have undergone multiple bridge-fusion-breakage cycles. We also observed examples of chromosomes with extensive ongoing end decay in mec1 tlc1 mutants, suggesting that Mec1 protects chromosome ends from degradation and contributes to telomere maintenance by HR. Conclusions/Significance HR between repeated sequences resulting in secondary rearrangements was the most prevalent pathway for resolution of dicentric GCRs regardless of the structure of the initial dicentric GCR, although at least three other resolution mechanisms were observed. The resolution of dicentric GCRs to stable rearranged chromosomes could in part account for the complex karyotypes seen in some cancers.

Pennaneach, Vincent; Kolodner, Richard D.

2009-01-01

405

Cytogenetic and molecular characteristics of 25 Chilean patients with a variant Ph translocation.  

PubMed

Chronic myeloid leukemia (CML) is characterized by the presence of the Philadelphia chromosome (Ph), which results from a balanced translocation between chromosomes 9 and 22, the t(9;22)(q34;q11.2). In 5-10% of the cases, variants of the Ph (vPh) are detected, involving various breakpoints in addition to 9q34 and 22q11.2. Deletions on the der(9) and der(22) can be detected in approximately 10-15% of CML patients. The frequency of a deletion of the der(9) in vPh CML is variable. Most studies have shown high frequencies (30-45%) in this subgroup. We report the cytogenetic evaluation of 25 vPh cases, which represents 6.8% of the CML cases diagnosed at one institution in 20 years. The breakpoints of the partners of the vPh in our patients agree with those reported previously, except for a novel 18q23. We found a low incidence of deletions of the der(9) (10%) and der(22) (5%) in these patients, contrasting with sever