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1

BCL2 translocation frequency rises with age in humans  

SciTech Connect

The background frequency of t(14;18) (q32;q21) chromosomal translocations at the locus associated with B-cell leukemia/lymphoma-2 (BCL2) was determined from a survey of the peripheral blood lymphocytes (PBLs) of 53 living individuals and from tissues of 31 autopsies by using a nested PCR assay. The translocation was detected in 55% of PBLs and 35% of autopsied spleens with a frequency of between less than 1 to 853 translocations per million cells. Translocations copurified with B lymphocytes. The frequency of translocations significantly increased with age in PBLs and spleens, as does human risk for lymphoma. Average translocation frequency was more than 40 times greater in the spleen and 13 times greater in the peripheral blood in the oldest individuals (61 yr and older) compared with the youngest individuals (20 yr or younger). Particular t(14;18)-bearing clones persisted over a period of 5 months in two individuals. These findings demonstrate that clones harboring the oncogenic t(14;18) chromosomal translocation are commonly present in normal humans, that such clones are long-lived, and that they rise in frequency with age. A multihit model of lymphomagenesis involving t(14;18) translocation followed by antigen stimulation is proposed. 49 refs., 8 figs., 1 tab.

Liu, Y.; Hernandez, A.M.; Shibata, D.; Cortopassi, G.A. [Univ. of Southern California, Los Angeles, CA (United States)

1994-09-13

2

BCL2 translocation frequency rises with age in humans.  

PubMed Central

The background frequency of t(14;18) (q32;q21) chromosomal translocations at the locus associated with B-cell leukemia/lymphoma-2 (BCL2) was determined from a survey of the peripheral blood lymphocytes (PBLs) of 53 living individuals and from tissues of 31 autopsies by using a nested PCR assay. The translocation was detected in 55% of PBLs and 35% of autopsied spleens with a frequency of between less than 1 to 853 translocations per million cells. Translocations copurified with B lymphocytes. The frequency of translocations significantly increased with age in PBLs and spleens, as does human risk for lymphoma. Average translocation frequency was more than 40 times greater in the spleen and 13 times greater in the peripheral blood in the oldest individuals (61 yr and older) compared with the youngest individuals (20 yr or younger). Particular t(14;18)-bearing clones persisted over a period of 5 months in two individuals. These findings demonstrate that clones harboring the oncogenic t(14;18) chromosomal translocation are commonly present in normal humans, that such clones are long-lived, and that they rise in frequency with age. A multihit model of lymphomagenesis involving t(14;18) translocation followed by antigen stimulation is proposed. Images

Liu, Y; Hernandez, A M; Shibata, D; Cortopassi, G A

1994-01-01

3

BCL2 Translocation Frequency Rises with Age in Humans  

Microsoft Academic Search

The background frequency of t(14;18) (q32;q21) chromosomal translocations at the locus associated with B-cell leukemia\\/lymphoma-2 (BCL2) was determined from a survey of the peripheral blood lymphocytes (PBLs) of 53 living individuals and from tissues of 31 autopsies by using a nested PCR assay. The translocation was detected in 55% of PBLs and 35% of autopsied spleens with a frequency of

Yafei Liu; Antonio M. Hernandez; Darryl Shibata; Gino A. Cortopassi

1994-01-01

4

Reciprocal translocations in cattle: frequency estimation.  

PubMed

Chromosomal anomalies, like Robertsonian and reciprocal translocations, represent a big problem in cattle breeding as their presence induces, in the carrier subjects, a well-documented fertility reduction. In cattle, reciprocal translocations (RCPs, a chromosome abnormality caused by an exchange of material between non-homologous chromosomes) are considered rare as to date only 19 reciprocal translocations have been described. In cattle, it is common knowledge that the Robertsonian translocations represent the most common cytogenetic anomalies, and this is probably due to the existence of the endemic 1;29 Robertsonian translocation. However, these considerations are based on data obtained using techniques that are unable to identify all reciprocal translocations, and thus, their frequency is clearly underestimated. The purpose of this work is to provide a first realistic estimate of the impact of RCPs in the cattle population studied, trying to eliminate the factors that have caused an underestimation of their frequency so far. We performed this work using a mathematical as well as a simulation approach and, as biological data, we considered the cytogenetic results obtained in the last 15 years. The results obtained show that only 16% of reciprocal translocations can be detected using simple Giemsa techniques, and consequently, they could be present in no <0.14% of cattle subjects, a frequency five times higher than that shown by de novo Robertsonian translocations. This data is useful to open a debate about the need to introduce a more efficient method to identify RCP in cattle. PMID:22963362

De Lorenzi, L; Morando, P; Planas, J; Zannotti, M; Molteni, L; Parma, P

2012-01-13

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

High frequency of t(14;18) translocation in salivary gland lymphomas from Sjogren's syndrome patients  

PubMed Central

Sjogren's syndrome (SS) is a chronic autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands. These patients have a markedly increased frequency of developing non- Hodgkin's lymphoma in their salivary glands and cervical lymph nodes. Translocations of proto-oncogene bcl-2 t(14;18) were observed in five of seven SS-associated lymphomas by Southern blot analysis. Using primers specific for chromosomes 14 and 18, translocation of the proto- oncogene bcl-2 was detected by polymerase chain reaction (PCR) in all five lymphomas positive by Southern blot analysis. Among SS patients lacking clinical evidence of coexistent lymphoma, no bcl-2 translocations were detected in 50 consecutive salivary gland biopsies. Of particular interest, pre-lymphoma biopsies were available from the seven SS patients who subsequently developed lymphoma and these DNA samples lacked detectable t(14;18) translocations even though they exhibited oligoclonal rearrangements of their immunoglobulin genes. We conclude that the great sensitivity of PCR can help us in detecting early onset of lymphoma in SS patients and aid in understanding the transition from autoimmunity to lymphoma.

1991-01-01

8

Fundamental frequency and speech intelligibility in background noise  

PubMed Central

Speech reception in noise is an especially difficult problem for listeners with hearing impairment as well as for users of cochlear implants (CIs). One likely cause of this is an inability to ‘glimpse’ a target talker in a fluctuating background, which has been linked to deficits in temporal fine-structure processing. A fine-structure cue that has the potential to be beneficial for speech reception in noise is fundamental frequency (F0). A challenging problem, however, is delivering the cue to these individuals. The benefits to speech intelligibility of F0 for both listeners with hearing impairment and users of CIs are reviewed, as well as various methods of delivering F0 to these listeners.

Brown, Christopher A.; Bacon, Sid P.

2009-01-01

9

Determination of the optimal excitation frequency range in background flows.  

PubMed

The chaotization of a vortical flow caused by a nonstationary incident flow is studied by the examples of several dynamically consistent models. It is shown that for relatively small values of excitation amplitude, the chaotization of such flows and, correspondingly, chaotic transport of passive scalars is determined by a small number of nonlinear resonances with frequencies close to the excitation frequency. Hence, the analysis of locations and overlaps of these resonances in the considered models makes it possible to derive fairly good estimates of excitation frequencies that are optimal for the chaotic transport. PMID:18377058

Izrailsky, Yu G; Koshel, K V; Stepanov, D V

2008-03-01

10

Background frequencies for residue variability estimates: BLOSUM revisited  

Microsoft Academic Search

BACKGROUND: Shannon entropy applied to columns of multiple sequence alignments as a score of residue conservation has proven one of the most fruitful ideas in bioinformatics. This straightforward and intuitively appealing measure clearly shows the regions of a protein under increased evolutionary pressure, highlighting their functional importance. The inability of the column entropy to differentiate between residue types, however, limits

I. Mihalek; I. Res; Olivier Lichtarge

2007-01-01

11

The origin of recurrent translocations in recombining lymphocytes: a balance between break frequency and nuclear proximity.  

PubMed

Translocations occur through the aberrant joining of large stretches of non-contiguous chromosomal regions. The substrates for these illegitimate rearrangements can arise as a result of damage incurred during normal cellular processes, such as transcription and replication, or through the action of genotoxic agents. In lymphocytes many translocations bear signs of having originated from abnormalities introduced during programmed recombination. Although recombination is tightly controlled at different levels, mistakes can occur leading to cytogenetic anomalies that include deletions, insertions, amplifications and translocations, which are an underlying cause of leukemias and lymphomas. In this review we focus on recent studies that provide insight into the origins of translocations that arise during the two lymphocyte specific programmed recombination events: V(D)J and class switch recombination (CSR). PMID:23478218

Rocha, Pedro P; Skok, Jane A

2013-03-13

12

Routine diagnostic X-ray examinations and increased frequency of chromosome translocations among U.S. radiologic technologists.  

PubMed

The U.S. population has nearly one radiographic examination per person per year, and concern about cancer risks associated with medical radiation has increased. Radiologic technologists were surveyed to determine whether their personal cumulative exposure to diagnostic X-rays was associated with increased frequencies of chromosome translocations, an established radiation biomarker and possible intermediary suggesting increased cancer risk. Within a large cohort of U.S. radiologic technologists, 150 provided a blood sample for whole chromosome painting and were interviewed about past X-ray examinations. The number and types of examinations reported were converted to a red bone marrow (RBM) dose score with units that approximated 1 mGy. The relationship between dose score and chromosome translocation frequency was assessed using Poisson regression. The estimated mean cumulative RBM radiation dose score was 49 (range, 0-303). After adjustment for age, translocation frequencies significantly increased with increasing RBM dose score with an estimate of 0.004 translocations per 100 cell equivalents per score unit (95% confidence interval, 0.002-0.007; P < 0.001). Removing extreme values or adjustment for gender, cigarette smoking, occupational radiation dose, allowing practice X-rays while training, work with radioisotopes, and radiotherapy for benign conditions did not affect the estimate. Cumulative radiation exposure from routine X-ray examinations was associated independently with increased chromosome damage, suggesting the possibility of elevated long-term health risks, including cancer. The slope estimate was consistent with expectation based on cytogenetic experience and atomic bomb survivor data. PMID:18974125

Sigurdson, Alice J; Bhatti, Parveen; Preston, Dale L; Doody, Michele Morin; Kampa, Diane; Alexander, Bruce H; Petibone, Dayton; Yong, Lee C; Edwards, Alan A; Ron, Elaine; Tucker, James D

2008-11-01

13

ROUTINE DIAGNOSTIC X-RAY EXAMINATIONS AND INCREASED FREQUENCY OF CHROMOSOME TRANSLOCATIONS AMONG U. S. RADIOLOGIC TECHNOLOGISTS  

PubMed Central

The U.S. population has nearly one radiographic examination per person per year and concern about cancer risks associated with medical radiation has increased. Radiologic technologists were surveyed to determine whether their personal cumulative exposure to diagnostic x-rays was associated with increased frequencies of chromosome translocations, an established radiation biomarker and possible intermediary suggesting increased cancer risk. Within a large cohort of U. S. radiologic technologists, 150 provided a blood sample for whole chromosome painting and were interviewed about past x-ray examinations. The number and types of examinations reported were converted to a red bone marrow (RBM) dose score with units that approximated 1 mGy. The relationship between dose score and chromosome translocation frequency was assessed using Poisson regression. The estimated mean cumulative RBM radiation dose score was 49 (range 0 – 303). After adjustment for age, translocation frequencies significantly increased with increasing RBM dose score with an estimate of 0.004 translocations per 100 cell equivalents per score unit (95% confidence interval 0.002 to 0.007; P < 0.001). Removing extreme values or adjustment for gender, cigarette smoking, occupational radiation dose, allowing practice x-rays while training, work with radioisotopes, and radiotherapy for benign conditions did not affect the estimate. Cumulative radiation exposure from routine x-ray examinations was associated independently with increased chromosome damage, suggesting the possibility of elevated long-term health risks, including cancer. The slope estimate was consistent with expectation based on cytogenetic experience and atomic bomb survivor data.

Sigurdson, Alice J.; Bhatti, Parveen; Preston, Dale L.; Doody, Michele Morin; Kampa, Diane; Alexander, Bruce H.; Petibone, Dayton; Yong, Lee C.; Edwards, Alan A.; Ron, Elaine; Tucker, James D.

2008-01-01

14

Massless scalar field quasi-normal frequencies of Schwarzschild black hole in the quintessence background  

NASA Astrophysics Data System (ADS)

We evaluate the massless scalar field quasi-normal frequencies of Schwarzschild black hole in the quintessence background, using the third-order WKB approximation method. Results show that quintessence decreases the oscillation frequency while increases the damping time of the scalar field. Moreover, with the increase of the quintessential state parameter ? q (the ratio of the pressure to the energy density), the imaginary parts' absolute values of the quasi-normal frequencies increase monotonously. This indicates that the scalar field decays more rapidly in the larger ? q quintessence state, which agrees with the cases of other perturbation fields for black holes in the quintessence background. For the special case of SdS black hole ( ? q =-1), the oscillation frequency and the damping rate increase with the decrease of the normalization factor c (corresponding to the cosmological constant ? in SdS black hole).

Guo, Guanghai

2013-09-01

15

Modifications to the cosmic 21-cm background frequency spectrum by scattering via electrons in galaxy clusters  

SciTech Connect

The cosmic 21-cm background frequency spectrum related to the spin-flip transition of neutral hydrogen present during and before the era of reionization is rich in features associated with physical processes that govern transitions between the two spin states. The intervening electrons in foreground galaxy clusters inversely Compton scatter the 21-cm background spectrum and modify it just as the cosmic microwave background (CMB) spectrum is modified by inverse-Compton scattering. Towards typical galaxy clusters at low redshifts, the resulting modification is a few tenths milli-Kelvin correction to the few tens milli-Kelvin temperature of 21-cm signal relative to that of the cosmic microwave background blackbody spectrum. The modifications are mostly associated with sharp changes in the cosmic 21-cm background spectrum such as due to the onset of a Lyman-{alpha} radiation field or heating of neutral gas. Though low-frequency radio interferometers that are now planned for 21-cm anisotropy measurements are insensitive to the mean 21-cm spectrum, differential observations of galaxy clusters with these interferometers can be utilized to indirectly establish global features in the 21-cm frequency spectrum. We discuss the feasibility to detect the spectrum modified by clusters and find that, for upcoming interferometers, while a detection towards an individual cluster is challenging, one can average signals over a number of clusters, selected based on the strength of the Sunyave-Zel'dovich effect at high radio frequencies involving CMB scattering alone, to establish the mean 21-cm spectrum.

Cooray, Asantha [Department of Physics and Astronomy, 4186 Frederick Reines Hall, University of California, Irvine, California 92697 (United States)

2006-05-15

16

Modifications to the cosmic 21-cm background frequency spectrum by scattering via electrons in galaxy clusters  

NASA Astrophysics Data System (ADS)

The cosmic 21-cm background frequency spectrum related to the spin-flip transition of neutral hydrogen present during and before the era of reionization is rich in features associated with physical processes that govern transitions between the two spin states. The intervening electrons in foreground galaxy clusters inversely Compton scatter the 21-cm background spectrum and modify it just as the cosmic microwave background (CMB) spectrum is modified by inverse-Compton scattering. Towards typical galaxy clusters at low redshifts, the resulting modification is a few tenths milli-Kelvin correction to the few tens milli-Kelvin temperature of 21-cm signal relative to that of the cosmic microwave background blackbody spectrum. The modifications are mostly associated with sharp changes in the cosmic 21-cm background spectrum such as due to the onset of a Lyman-? radiation field or heating of neutral gas. Though low-frequency radio interferometers that are now planned for 21-cm anisotropy measurements are insensitive to the mean 21-cm spectrum, differential observations of galaxy clusters with these interferometers can be utilized to indirectly establish global features in the 21-cm frequency spectrum. We discuss the feasibility to detect the spectrum modified by clusters and find that, for upcoming interferometers, while a detection towards an individual cluster is challenging, one can average signals over a number of clusters, selected based on the strength of the Sunyave-Zel’dovich effect at high radio frequencies involving CMB scattering alone, to establish the mean 21-cm spectrum.

Cooray, Asantha

2006-05-01

17

Theta Frequency Background Tunes Transmission but Not Summation of Spiking Responses  

PubMed Central

Hippocampal neurons are known to fire as a function of frequency and phase of spontaneous network rhythms, associated with the animal's behaviour. This dependence is believed to give rise to precise rate and temporal codes. However, it is not well understood how these periodic membrane potential fluctuations affect the integration of synaptic inputs. Here we used sinusoidal current injection to the soma of CA1 pyramidal neurons in the rat brain slice to simulate background oscillations in the physiologically relevant theta and gamma frequency range. We used a detailed compartmental model to show that somatic current injection gave comparable results to more physiological synaptically driven theta rhythms incorporating excitatory input in the dendrites, and inhibitory input near the soma. We systematically varied the phase of synaptic inputs with respect to this background, and recorded changes in response and summation properties of CA1 neurons using whole-cell patch recordings. The response of the cell was dependent on both the phase of synaptic inputs and frequency of the background input. The probability of the cell spiking for a given synaptic input was up to 40% greater during the depolarized phases between 30–135 degrees of theta frequency current injection. Summation gain on the other hand, was not affected either by the background frequency or the phasic afferent inputs. This flat summation gain, coupled with the enhanced spiking probability during depolarized phases of the theta cycle, resulted in enhanced transmission of summed inputs during the same phase window of 30–135 degrees. Overall, our study suggests that although oscillations provide windows of opportunity to selectively boost transmission and EPSP size, summation of synaptic inputs remains unaffected during membrane oscillations.

Parameshwaran, Dhanya; Bhalla, Upinder S.

2013-01-01

18

Background frequency, information content, and the scoring matrix in sequence alignment  

NASA Astrophysics Data System (ADS)

Sequence alignment tools for protein/DNA sequences have been widely used to find homologous biosequences over the past few decades. In these automated procedures, the target similarity between the two sequences compared is largely determined by the scoring matrix used. Theoretically, each matrix element of the scoring matrix is a log-odd ratio, i.e., the logarithm of the target frequency over the background frequency. In real alignment applications, however, the theoretical criterion is often overlooked. In this talk, we will present a sensible solution to forcibly maintain the theoretical criterion. We will also discuss the information content of the scoring matrix.

Yu, Yi-Kuo; Altschul, Stephen

2003-03-01

19

Low-frequency measurements of the CMB (cosmic microwave background) spectrum  

SciTech Connect

As part of an extended program to characterize the spectrum of the cosmic microwave background (CMB) at low frequencies, we have performed multiple measurements from a high-altitude site in California. On average, these measurements suggest a CMB temperature slightly lower than measurements at higher frequencies. Atmospheric conditions and the encroachment of civilization are now significant limitations from our present observing site. In November 1989, we will make new measurements from the South Pole Amnudsen-Scott Station at frequencies 0.82 1.5, 2.5, 3.8, 7.5, and 90 GHz. We discuss recent measurements and indicate improvements from a polar observing site. 11 refs., 2 figs.

Kogut, A.; Bensadoun, M.; De Amici, G.; Levin, S.; Limon, M.; Smoot, G. (Lawrence Berkeley Lab., CA (USA)); Sironi, G. (Milan Univ. (Italy). Dipt. di Fisica); Bersanelli, M.; Bonelli, G. (Consiglio Nazionale delle Ricerche, Milan (Italy))

1989-10-01

20

Toward a high-temporal-frequency grass canopy thermal IR model for background signatures  

NASA Astrophysics Data System (ADS)

In this paper, we present our first results towards understanding high temporal frequency thermal infrared response from a dense grass canopy. The model is driven by slowly varying, time-averaged meteorological conditions and by high frequency measurements of local and within canopy profiles of relative humidity and wind speed, and compared to high frequency thermal infrared observations. Previously, we have employed three-dimensional ray tracing to compute the intercepted and scattered solar and IR radiation fluxes and for final scene rendering. For the turbulent fluxes, simple resistance models for latent and sensible heat with one-dimensional profiles of relative humidity and wind speed are used. 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 sec to 5 min 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.

2004-08-01

21

Cosmological and Astrophysical Information Content in the Low Radio Frequency 21-cm Background from High Redshifts  

NASA Astrophysics Data System (ADS)

We will discuss the prospects for extracting cosmological and astrophysical parameters from the low radio frequency 21-cm background due to the spin-flip transition of neutral Hydrogen during and prior to the reionization of the Universe with radio interferometric arrays such as LOFAR and SKA We will discuss the measurement of the angular power spectrum of 21-cm anistropies, which exists due to inhomogeneities in the neutral Hydrogen density field, the gas temperature field, the intensity of the Lyman-alpha radiation from first luminous sources that emit UV photons, and the gas velocity. We consider the general case where fluctuations are induced by a variety of sources during the era of reionization. We attempt to extract parameters that describe both the underlying mass power spectrum and the global cosmology, as well as a set of simplified astrophysical parameters that connect fluctuations in the dark matter to those that govern 21-cm fluctuations by marginalizing over a model for the foregrounds at low radio frequencies. In this general description, we find large degeneracies between cosmological parameters and astrophysical parameters, though such degeneracies are not present when strong assumptions are made with respect to the spin temperature relative to the CMB temperature. Some of the parameter degeneracies are broken when 21-cm measurements are combined with information from the CMB, such as anisotropy and polarization measurements with Planck. For upcoming low frequency radio interferometers, the overall improvement on the cosmological parameter estimates when combined with Planck is not significant; we suggest that low radio frequency 21-cm measurements are, at best, suitable to understand certain astrophysical details during the era of recombination, but neither the shape of the power spectrum nor the global cosmological parameters.

Cooray, A.

2006-08-01

22

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

23

Haplotypic Background of a Private Allele at High Frequency in the Americas  

PubMed Central

Recently, the observation of a high-frequency private allele, the 9-repeat allele at microsatellite D9S1120, in all sampled Native American and Western Beringian populations has been interpreted as evidence that all modern Native Americans descend primarily from a single founding population. However, this inference assumed that all copies of the 9-repeat allele were identical by descent and that the geographic distribution of this allele had not been influenced by natural selection. To investigate whether these assumptions are satisfied, we genotyped 34 single nucleotide polymorphisms across ?500 kilobases (kb) around D9S1120 in 21 Native American and Western Beringian populations and 54 other worldwide populations. All chromosomes with the 9-repeat allele share the same haplotypic background in the vicinity of D9S1120, suggesting that all sampled copies of the 9-repeat allele are identical by descent. Ninety-one percent of these chromosomes share the same 76.26 kb haplotype, which we call the “American Modal Haplotype” (AMH). Three observations lead us to conclude that the high frequency and widespread distribution of the 9-repeat allele are unlikely to be the result of positive selection: 1) aside from its association with the 9-repeat allele, the AMH does not have a high frequency in the Americas, 2) the AMH is not unusually long for its frequency compared with other haplotypes in the Americas, and 3) in Latin American mestizo populations, the proportion of Native American ancestry at D9S1120 is not unusual compared with that observed at other genomewide microsatellites. Using a new method for estimating the time to the most recent common ancestor (MRCA) of all sampled copies of an allele on the basis of an estimate of the length of the genealogy descended from the MRCA, we calculate the mean time to the MRCA of the 9-repeat allele to be between 7,325 and 39,900 years, depending on the demographic model used. The results support the hypothesis that all modern Native Americans and Western Beringians trace a large portion of their ancestry to a single founding population that may have been isolated from other Asian populations prior to expanding into the Americas.

Schroeder, Kari B.; Jakobsson, Mattias; Crawford, Michael H.; Schurr, Theodore G.; Boca, Simina M.; Conrad, Donald F.; Tito, Raul Y.; Osipova, Ludmilla P.; Tarskaia, Larissa A.; Zhadanov, Sergey I.; Wall, Jeffrey D.; Pritchard, Jonathan K.; Malhi, Ripan S.; Smith, David G.; Rosenberg, Noah A.

2009-01-01

24

Haplotypic background of a private allele at high frequency in the Americas.  

PubMed

Recently, the observation of a high-frequency private allele, the 9-repeat allele at microsatellite D9S1120, in all sampled Native American and Western Beringian populations has been interpreted as evidence that all modern Native Americans descend primarily from a single founding population. However, this inference assumed that all copies of the 9-repeat allele were identical by descent and that the geographic distribution of this allele had not been influenced by natural selection. To investigate whether these assumptions are satisfied, we genotyped 34 single nucleotide polymorphisms across approximately 500 kilobases (kb) around D9S1120 in 21 Native American and Western Beringian populations and 54 other worldwide populations. All chromosomes with the 9-repeat allele share the same haplotypic background in the vicinity of D9S1120, suggesting that all sampled copies of the 9-repeat allele are identical by descent. Ninety-one percent of these chromosomes share the same 76.26 kb haplotype, which we call the "American Modal Haplotype" (AMH). Three observations lead us to conclude that the high frequency and widespread distribution of the 9-repeat allele are unlikely to be the result of positive selection: 1) aside from its association with the 9-repeat allele, the AMH does not have a high frequency in the Americas, 2) the AMH is not unusually long for its frequency compared with other haplotypes in the Americas, and 3) in Latin American mestizo populations, the proportion of Native American ancestry at D9S1120 is not unusual compared with that observed at other genomewide microsatellites. Using a new method for estimating the time to the most recent common ancestor (MRCA) of all sampled copies of an allele on the basis of an estimate of the length of the genealogy descended from the MRCA, we calculate the mean time to the MRCA of the 9-repeat allele to be between 7,325 and 39,900 years, depending on the demographic model used. The results support the hypothesis that all modern Native Americans and Western Beringians trace a large portion of their ancestry to a single founding population that may have been isolated from other Asian populations prior to expanding into the Americas. PMID:19221006

Schroeder, Kari B; Jakobsson, Mattias; Crawford, Michael H; Schurr, Theodore G; Boca, Simina M; Conrad, Donald F; Tito, Raul Y; Osipova, Ludmilla P; Tarskaia, Larissa A; Zhadanov, Sergey I; Wall, Jeffrey D; Pritchard, Jonathan K; Malhi, Ripan S; Smith, David G; Rosenberg, Noah A

2009-02-12

25

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

26

Dependence of the resonant electromagnetic background frequencies in the frequency range of the alfven ionospheric resonator on the level of the solar activity  

NASA Astrophysics Data System (ADS)

In the work, variations of the resonant electromagnetic background frequencies in the frequency range of the ionospheric Alfven resonator are investigated. An algorithm of automatic determination of the resonant characteristics of registered signals is presented. It is established that the variations of the resonant frequencies are determined on 75% by their seasonal changes; the relative contribution of the 11-year period caused by the solar activity does not exceed 15%.

Kolesnik, A. G.; Kolesnik, S. A.; Kolmakov, A. A.; Chernyshev, I. V.

2011-02-01

27

Basal and induced micronucleus frequencies in human lymphocytes with different GST and NAT2 genetic backgrounds  

Microsoft Academic Search

Basal and induced frequencies of genetic damage can be modulated by different host factors, including genes involved in phase II metabolism. Since polymorphic variants in the glutathione S-transferase (GST) and N-acetyl transferase (NAT) genes have been associated with cancer risk, we explored the possible links between GSTM1, GSTP1, GSTT1 and NAT2 variants and the frequency of micronuclei (MN) in human

Alba Hernández; Noel Xamena; Sara Gutiérrez; Antonia Velázquez; Amadeu Creus; Jordi Surrallés; Pere Galofré; Ricardo Marcos

2006-01-01

28

Atypical background somatic mutant frequencies at the HPRT locus in children and adults with Down syndrome  

Microsoft Academic Search

People with Down syndrome are 10–30 fold more likely to develop leukemia than the normal population. To date, little is known regarding the molecular mechanisms underlying this phenomenon. We have previously demonstrated that the spontaneous somatic mutant frequency (Mf) at a reporter gene, hypoxanthine-guanine phosphoribosyl transferase (HPRT), from a normal population showed a strict age dependency with an exponential increase

B. A. Finette; B. Rood; T. Poseno; P. Vacek; S. Pueschel; A. C. Homans

1998-01-01

29

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

30

Human perception of acoustic models of spatial sound translocation on the background of hearing and production of verbal signals (ontogenetic aspect)  

Microsoft Academic Search

Studied in the work was human perception of acoustic signals changing in amplitude on the background of production and hearing of syllables composed, from the ontogenetic viewpoint, of the “earliest” and the “latest” consonants and vowels —[pa] and [ly], as well as on the background of noise. It was shown that on the background of the syllable pronunciation their recognition

A. I. Vartanyan; T. I. Tokareva; N. K. Lange

2004-01-01

31

Type II solar radio burst with reverse frequency drift against the background of a noise storm  

SciTech Connect

On November 19, 1975, a type II radio burst was observed in which the drift of the radiation in the meter wavelength range from low to high frequencies was accompanied by gradual cessation of the noise storm. This phenomenon is interpreted as the result of the interaction of a shock wave, propagating in the direction of increasing electron density, with the source of the noise storm.

Korolev, O.S.; Fomichev, V.V.; Chertok, I.M.

1979-03-01

32

Nuclear background affects frequency dynamics of mitochondrial DNA variants in Drosophila simulans  

Microsoft Academic Search

Transplasmic lines, in which the original mitochondrial DNA (mtDNA) had been completely replaced by the mtDNA of the donor, were constructed to test for selection on mtDNA variants and to investigate the effects of nuclear-cytoplasmic interactions in Drosophila simulans. These lines were used to set up 12 experimental populations putting in competition two mtDNA variants with two different starting frequencies.

Loredana Nigro

1994-01-01

33

Propagation of the two-frequency coherence function in an inhomogeneous background random medium  

Microsoft Academic Search

The spatial and temporal structures of time-dependent signals can be appreciably affected by random changes of the parameters of the medium characteristic of almost all geophysical environments. The dispersive properties of random media cause distortions in the propagating signal, particularly in pulse broadening and time delay. When there is also spatial variation of the background refractive index, the observer can

Alexander Kalugin; Alexander Bronshtein; Reuven Mazar

2004-01-01

34

Translocal spatiality  

Microsoft Academic Search

•Instead of exploring the global\\/local logic of glocalization, this case study specifically concentrates on a form of local-to-local spatial dynamics. The spatial history of Hong Kong underground bandrooms is exploited to illustrate the translocal reproduction of spatiality. While the construction of this space was translocally inspired by music subculture from abroad, local spatiality absorbs transborder subcultural energies and re-channels them

Eric Kit-wai Ma

2002-01-01

35

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

36

Wave number refraction and frequency modulation of medium scale gravity waves in 3-dimensional time-dependent background flows  

NASA Astrophysics Data System (ADS)

Going beyond the frame of classical vertical column thinking the inclusion of horizontal gradients of a background flow in the description of gravity waves (GWs) can have important impacts on GW propagation and its action back on that type of flows. The horizontal wave number and the wave-related horizontal pseudo-momentum can be refracted to different scales and azimuth directions which may lead to substantial changes in regions of dissipative pseudo-momentum deposition and therefore mean flow forcing. In this sense wave number refraction can have a remote effect in a distant dissipation region. Additionally, the time dependence of a background flow may lead to changes in the absolute, or sometimes called ground-based, frequency of the GWs moving through it. For periodic background flows a periodic frequency modulation is excited. Beside the conservative transient forcing the periodicity of frequency also changes the background flow forcing in dissipation regions. This effect does not appear in the commonly used approximation of an instantaneously adjusting GW train. In our contribution we use a sophisticated ray tracing method to infer the effects of the time dependence and horizontal gradients of diurnal solar-thermal tides plus a realistic 3-dimensional steady mean flow on the propagation of medium scale gravity waves in the middle atmosphere. Strongest wave number refraction and frequency modulation effects occur for slowly propagating GWs. Due to large tidal wind variations in the upper mesosphere most parts of the assumed GW spectrum are slowed down in critical layer type regions. Then, the combined action of horizontal wave number refraction and frequency modulation induce changes in the horizontal phase speed which may exceed orders of magnitude compared to the initial phase speed. The phase speed variations have the tendency to follow the shape of the tidal background wind. This effect leads to less critical layer filtering of GWs and therefore decreased periodic background flow forcing due to momentum flux divergences as compared to a classical vertical column parametrization of instantaneously adjusting GW trains.

Senf, Fabian; Achatz, Ulrich

2010-05-01

37

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

38

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

39

Signal photon flux and background noise in a coupling electromagnetic detecting system for high-frequency gravitational waves  

SciTech Connect

A coupling system among Gaussian-type microwave photon flux, a static magnetic field, and fractal membranes (or other equivalent microwave lenses) can be used to detect high-frequency gravitational waves (HFGWs) in the microwave band. We study the signal photon flux, background photon flux, and the requisite minimal accumulation time of the signal in the coupling system. Unlike the pure inverse Gertsenshtein effect (G effect) caused by the HFGWs in the gigahertz band, the electromagnetic (EM) detecting scheme proposed by China and the U.S. HFGW groups is based on the composite effect of the synchroresonance effect and the inverse G effect. The key parameter in the scheme is the first-order perturbative photon flux (PPF) and not the second-order PPF; the distinguishable signal is the transverse first-order PPF and not the longitudinal PPF; the photon flux focused by the fractal membranes or other equivalent microwave lenses is not only the transverse first-order PPF but the total transverse photon flux, and these photon fluxes have different signal-to-noise ratios at the different receiving surfaces. Theoretical analysis and numerical estimation show that the requisite minimal accumulation time of the signal at the special receiving surfaces and in the background noise fluctuation would be {approx}10{sup 3}-10{sup 5} seconds for the typical laboratory condition and parameters of h{sub rms}{approx}10{sup -26}-10{sup -30}/{radical}(Hz) at 5 GHz with bandwidth {approx}1 Hz. In addition, we review the inverse G effect in the EM detection of the HFGWs, and it is shown that the EM detecting scheme based only on the pure inverse G effect in the laboratory condition would not be useful to detect HFGWs in the microwave band.

Li Fangyu; Yang Nan; Fang Zhenyun; Wen Hao [Department of Physics, Chongqing University, Chongqing 400044 (China); Baker, Robert M. L. Jr. [GRAWAVE registered LLC, 8123 Tuscany Avenue, Playa del Rey, California 90293 (United States); Stephenson, Gary V. [Seculine Consulting, P.O. Box 925, Redondo Beach, California 90277 (United States)

2009-09-15

40

Acoustic monitoring of background internal waves with the use of the correlation method for measuring the frequency shifts of interference maxima  

NASA Astrophysics Data System (ADS)

A numerical experiment is carried out to demonstrate the reconstruction of the frequency spectrum of background internal waves with the use of the correlation method for measuring the frequency shifts of interference maxima. The method is based on monitoring the behavior of the frequency shift for the maximum of the cross-correlation function of signal spectra received at different instants of time. The noise immunity of the correlation method is analyzed in comparison with the direct method based on monitoring the frequency shift of a chosen maximum of the interference pattern.

Kuz'kin, V. M.; Pereselkov, S. A.

2011-07-01

41

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

2013-06-27

42

Investigation of radio frequency discharges and Langmuir probe diagnostic methods in a fast flowing electronegative background gas  

Microsoft Academic Search

Discharges in a flowing background gas are used to produce charged and excited atomic and molecular species for numerous applications including etching semiconductors, pumping gas discharge lasers, and a variety of other applications (Pinhero and others, 1998). The effect of a flowing background gas on the charged and excited neutral species generation by an RF discharge in a flow tube

Nathaniel P. Lockwood

2007-01-01

43

High relative frequency of oral squamous cell carcinoma in Yemen: Qat and tobacco chewing as its aetiological background  

Microsoft Academic Search

To study the association of qat chewing with the occurrence of oral cancer, the frequency of oral cancer among whole body cancers and the patients' histories of tobacco consumption and qat chewing were examined in Yemen where qat chewing has been most popular. All primary malignant tumors listed in the surgical pathology files at Al-Thawra Hospital, University of Sana'a, in

Faleh A. Sawair; Ammar Al-Mutwakel; Kamal Al-Eryani; Ameera Al-Surhy; Satoshi Maruyama; Jun Cheng; Ali Al-Sharabi; Takashi Saku

2007-01-01

44

Frequency-dependent seed size selection on Cryptocarya alba (Mol.) Looser (Lauraceae): testing the effect of background  

Microsoft Academic Search

Seed size affects the probability of seed predation. Large seeds should be preferred over small seeds but the selective responses of seed predators may also be frequency-dependent. Seed predators may prefer the most common seed sizes (apostatic selection), the rarest ones (antiapostatic selection) or even be unresponsive to the size of seeds. More- over, seed density may further modify the

J. L. CELIS-DIEZ; R. O. BUSTAMANTE

2005-01-01

45

Translocation Renal Cell Carcinomas in Adults: A Single Institution Experience  

PubMed Central

Translocation renal cell carcinoma is a newly recognized subtype of renal cell carcinoma (RCC) with chromosomal translocations involving TFE3 (Xp11.2) or, less frequently, TFEB (6p21). Xp11 translocation RCC was originally described as a pediatric neoplasm representing 20–40% of pediatric RCCs with a much lower frequency in the adult population. TFEB translocation RCC is very rare, with approximately 10 cases reported in the literature. Here, we describe the clinicopathological features of adult translocation RCC from a single institution. Utilizing tissue microarray (TMA), immunohistochemistry, cytogenetic examination, and FISH, we identified 6 (~5%) cases of TFE3 translocation RCC and 1 (<1%) case of TFEB translocation RCC in 121 consecutive adult renal cell carcinoma cases between 2001 and 2009. Our results suggest that weak TFE3 staining of a significant proportion of RCC cases may due to expression of the full length TFE3 protein rather than the chimeric fusion protein resulting from chromosomal translocation.

Zhong, Minghao; De Angelo, Patricia; Osborne, Lisa; Mondolfi, Paniz; Geller, Matthew; Yang, Youfeng; Linehan, W. Marston; Merino, Maria J.; Cordon-Cardo, Carlos; Cai, Dongming

2012-01-01

46

Wave number refraction and frequency modulation of medium scale gravity waves in 3-dimensional time-dependent background flows  

Microsoft Academic Search

Going beyond the frame of classical vertical column thinking the inclusion of horizontal gradients of a background flow in the description of gravity waves (GWs) can have important impacts on GW propagation and its action back on that type of flows. The horizontal wave number and the wave-related horizontal pseudo-momentum can be refracted to different scales and azimuth directions which

Fabian Senf; Ulrich Achatz

2010-01-01

47

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

PubMed

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. PMID:20968378

Apoux, Frédéric; Healy, Eric W

2010-10-01

48

High relative frequency of oral squamous cell carcinoma in Yemen: qat and tobacco chewing as its aetiological background.  

PubMed

To study the association of qat chewing with the occurrence of oral cancer, the frequency of oral cancer among whole body cancers and the patients' histories of tobacco consumption and qat chewing were examined in Yemen where qat chewing has been most popular. All primary malignant tumors listed in the surgical pathology files at Al-Thawra Hospital, University of Sana'a, in the year 2004 were analyzed, and the patients' histories of tobacco consumption and qat chewing were examined. A total of 649 cases of primary malignant tumors (348, 53.6% males and 301, 46.4% females) were extracted. Oral cancer was the most frequent body cancer in both males (17.2%) and females (19.6%). Squamous cell carcinoma (SCC) was the most frequent oral cancer (84%), and the tongue (42%), gingiva (23%) and buccal mucosa (20%) were the most common sites. Among the 119 patients with oral cancer, information on chewing habits and smoking was obtained in 92 patients (77.3%). There were 70 tobacco chewers (76.1%), 55 qat chewers (59.8%), and 22 smokers (23.9%). Simultaneous chewing of tobacco and qat was found in 48 cases (52.2%). The present survey has disclosed for the first time that oral SCC is the most frequent cancer in this study area in Yemen, and that the high relative frequency of oral SCC may be related to the habits of chewing tobacco and qat. PMID:17479382

Sawair, Faleh A; Al-Mutwakel, Ammar; Al-Eryani, Kamal; Al-Surhy, Ameera; Maruyama, Satoshi; Cheng, Jun; Al-Sharabi, Ali; Saku, Takashi

2007-06-01

49

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

2012-08-25

50

Possible interchromosomal effect in embryos generated by gametes from translocation carriers  

Microsoft Academic Search

BACKGROUND: The incidence of abnormal pregnancies in carriers of balanced translocations depends strictly on the chromosomes involved in the translocations. The aim of this study was to verify whether conventional aneuploidy screening could be advantageously combined with preimplantation genetic diagnosis (PGD) for translocations. METHODS: Twenty-eight carriers of Robertsonian and reciprocal translocations underwent 43 PGD cycles; specific probes were used to

L. Gianaroli; M. C. Magli; A. P. Ferraretti; S. Munne; B. Balicchia; T. Escudero; A. Crippa

2002-01-01

51

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

2012-10-04

52

Chromosome translocations: a biomarker for retrospective biodosimetry.  

PubMed Central

We discuss here the results from our studies demonstrating that simple translocations detected by chromosome painting can be used to reconstruct radiation doses for workers exposed within the dose limits and for individuals with past exposure. To be useful, a biomarker for exposure and risk assessment should employ an end point that is highly quantitative, stable over time, and relevant to human risk. Recent advances in chromosome staining using fluorescence in situ hybridization facilitate fast and reliable measurement of simple translocations, a type of DNA damage linked both to prior clastogenic exposure and to risk. In contrast to other biomarkers available, the frequency of simple translocations in individuals exposed to whole-body radiation is stable over time postexposure, has little interindividual variability, and can be measured accurately at low frequencies.

Lucas, J N

1997-01-01

53

Single cell translocations in couples with multiple spontaneous abortions  

Microsoft Academic Search

Single cell translocations have been previously reported to occur in normal lymphocyte cultures. Comparison of the frequency of these in 140 individuals referred for a history of multiple miscarriages and 415 individuals referred for other reasons showed a significantly greater number of single cell translocations in the former group. This group also had a significantly greater number of other types

Michael D. Higgins; Catherine G. Palmer

1987-01-01

54

Chromosomal translocations and palindromic AT-rich repeats  

PubMed Central

Repetitive DNA sequences constitute 30% of the human genome, and are often sites of genomic rearrangement. Recently, it has been found that several constitutional translocations, especially those that involve chromosome 22, take place utilizing palindromic sequences on 22q11 and on the partner chromosome. Analysis of translocation junction fragments shows that the breakpoints of such palindrome-mediated translocations are localized at the center of palindromic AT-rich repeats (PATRRs). The presence of PATRRs at the breakpoints, indicates a palindrome-mediated mechanism involved in the generation of these constitutional translocations. Identification of these PATRR-mediated translocations suggests a universal pathway for gross chromosomal rearrangement in the human genome. De novo occurrences of PATRR-mediated translocations can be detected by PCR in normal sperm samples but not somatic cells. Polymorphisms of various PATRRs influence their propensity for adopting a secondary structure, which in turn affects de novo translocation frequency. We propose that the PATRRs form an unstable secondary structure, which leads to double-strand breaks at the center of the PATRR. The double-strand breaks appear to be followed by a non-homologous end-joining repair pathway, ultimately leading to the translocations. This review considers recent findings concerning the mechanism of meiosis-specific, PATRR-mediated translocations.

Kato, Takema; Kurahashi, Hiroki; Emanuel1, Beverly S.

2012-01-01

55

Simulations of Polymer Translocation  

NASA Astrophysics Data System (ADS)

Transport of molecules across membranes is an essential mechanism for life processes. These molecules are often long, and the pores in the membranes are too narrow for the molecules to pass through as a single unit. In such circumstances, the molecules have to squeeze -- i.e., translocate -- themselves through the pores. DNA, RNA and proteins are such naturally occuring long molecules in a variety of biological processes. Understandably, the process of translocation has been an active topic of current research: not only because it is a cornerstone of many biological processes, but also due to its relevance for practical applications. Translocation is a complicated process in living organisms -- the presence of chaperone molecules, pH, chemical potential gradients, and assisting molecular motors strongly influence its dynamics. Consequently, the translocation process has been empirically studied in great variety in biological literature. Study of translocation as a biophysical process is more recent. Herein, the polymer is simplified to a sequentially connected string of N monomers as it passes through a narrow pore on a membrane. The quantities of interest are the typical time scale for the polymer to leave a confining cell (the ``escape of a polymer from a vesicle'' time scale), and the typical time scale the polymer spends in the pore (the ``dwell'' time scale) as a function of N and other parameters like membrane thickness, membrane adsorption, electrochemical potential gradient, etc. Our research is focused on computer simulations of translocation. Since our main interest is in the scaling properties, we use a highly simplified description of the translocation process. The polymer is described as a self-avoiding walk on a lattice, and its dynamics consists of single-monomer jumps from one lattice site to another neighboring one. Since we have a very efficient program to simulate such polymer dynamics, which we decribe in Chapter 2, we can perform long simulations in which long polymers creep through tiny pores. In Chapter 3 we study pore blockage times for a translocating polymer of length N, driven by a field E across te pore. In three dimensions we find that the typical time the pore remains blocked during a translocation event scales as N^{1.37}/E We show that the scaling behavior stems from the polymer dynamics at the immediate vicinity of the pore -- in particular, the memory effects in the polymer chain tension imbalance across the pore. Chapter 4 studies the unbiased translocation of a polymer with length N, surrounded by equally long polymers, through a narrow pore in a membrane. We show that in dense polymeric systems a relaxation time exists that scales as N^{2.65}, much longer than the Rouse time N^2. If the polymers are well entangled, we find that the mean dwell times scales as N^{3.3}, while for shorter, less entangled polymers, we measure dwell times scaling as N^{2.7}. In Chapter 5 we study the translocation of an RNA molecule, pulled through a nanopore by an optical tweezer, as a method to determine its secondary structure. The resolution with which the elements of the secondary structure can be determined is limited by thermal fluctuations, ruling out single-nucleotide resolution under normal experimental conditions.

Vocks, H.

2008-07-01

56

Translocation through environments with time dependent mobility  

NASA Astrophysics Data System (ADS)

We consider single particle and polymer translocation where the frictional properties experienced from the environment are changing in time. This work is motivated by the interesting frequency responsive behaviour observed when a polymer is passing through a pore with an oscillating width. In order to explain this better we construct general diffusive and non-diffusive frequency response of the gain in translocation time for a single particle in changing environments and look at some specific variations. For two state confinement, where the particle either has constant drift velocity or is stationary, we find exact expressions for both the diffusive and non-diffusive gain. We then apply this approach to polymer translocation under constant forcing through a pore with a sinusoidally varying width. We find good agreement for small polymers at low frequency oscillation with deviations occurring at longer lengths and higher frequencies. Unlike periodic forcing of a single particle at constant mobility, constant forcing with time dependent mobility is amenable to exact solution through manipulation of the Fokker-Planck equation.

Cohen, Jack A.; Chaudhuri, Abhishek; Golestanian, Ramin

2012-11-01

57

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

58

DNA damage defines sites of recurrent chromosomal translocations in B lymphocytes  

PubMed Central

Recurrent chromosomal translocations underlie both haematopoietic and solid tumours. Their origin has been ascribed to selection of random rearrangements, targeted DNA damage, or frequent nuclear interactions between translocation partners; however, the relative contribution of each of these elements has not been measured directly or on a large scale. Here we examine the role of nuclear architecture and frequency of DNA damage in the genesis of chromosomal translocations by measuring these parameters simultaneously in cultured mouse B lymphocytes. In the absence of recurrent DNA damage, translocations between Igh or Myc and all other genes are directly related to their contact frequency. Conversely, translocations associated with recurrent site-directed DNA damage are proportional to the rate of DNA break formation, as measured by replication protein A accumulation at the site of damage. Thus, non-targeted rearrangements reflect nuclear organization whereas DNA break formation governs the location and frequency of recurrent translocations, including those driving B-cell malignancies.

Hakim, Ofir; Resch, Wolfgang; Yamane, Arito; Klein, Isaac; Kieffer-Kwon, Kyong-Rim; Jankovic, Mila; Oliveira, Thiago; Bothmer, Anne; Voss, Ty C.; Ansarah-Sobrinho, Camilo; Mathe, Ewy; Liang, Genqing; Cobell, Jesse; Nakahashi, Hirotaka; Robbiani, Davide F.; Nussenzweig, Andre; Hager, Gordon L.; Nussenzweig, Michel C.; Casellas, Rafael

2012-01-01

59

DNA damage defines sites of recurrent chromosomal translocations in B lymphocytes.  

PubMed

Recurrent chromosomal translocations underlie both haematopoietic and solid tumours. Their origin has been ascribed to selection of random rearrangements, targeted DNA damage, or frequent nuclear interactions between translocation partners; however, the relative contribution of each of these elements has not been measured directly or on a large scale. Here we examine the role of nuclear architecture and frequency of DNA damage in the genesis of chromosomal translocations by measuring these parameters simultaneously in cultured mouse B lymphocytes. In the absence of recurrent DNA damage, translocations between Igh or Myc and all other genes are directly related to their contact frequency. Conversely, translocations associated with recurrent site-directed DNA damage are proportional to the rate of DNA break formation, as measured by replication protein A accumulation at the site of damage. Thus, non-targeted rearrangements reflect nuclear organization whereas DNA break formation governs the location and frequency of recurrent translocations, including those driving B-cell malignancies. PMID:22314321

Hakim, Ofir; Resch, Wolfgang; Yamane, Arito; Klein, Isaac; Kieffer-Kwon, Kyong-Rim; Jankovic, Mila; Oliveira, Thiago; Bothmer, Anne; Voss, Ty C; Ansarah-Sobrinho, Camilo; Mathe, Ewy; Liang, Genqing; Cobell, Jesse; Nakahashi, Hirotaka; Robbiani, Davide F; Nussenzweig, Andre; Hager, Gordon L; Nussenzweig, Michel C; Casellas, Rafael

2012-02-07

60

[Efficient production of wheat alien translocation lines and characterization by molecular cytogenetics].  

PubMed

The Triticum aestivum-Leymus mollis and T. aestivum-Thinopyrum intermedium translocation lines were induced by gametocidal chromosome 3C derived from Aegilops triuncialis and gamma-ray irradiated pollens of a T. aestivum-Th. intermedium addition line TAI-14 with a lower dosage (10Gy), respectively. By genomic in situ hybridization (GISH) analysis, three T. aestivum-L. mollis translocation lines (WM-10, WM-43 and WM-47) and three deletion lines (WM-18, WM-43 and WM-44) were selected from 59 F2 plants derived from a cross combination of T. aestivum-L. mollis substitution line M8724-8-13 x T. aestivum-Ae. triunicalis 3C chromosome addition line. The frequency of translocation lines produced and total frequency of chromosome structural variation occurred were 5.08% and 8.47%, respectively. Two of the three translocation lines, WM-10 and WM-43 all were heterozygous translocation lines carrying one T. aestivum-L. mollis Robertsonian translocation chromosome, but the translocation chromosome in the two lines were different in morphology. The other one, WM-47 was a double heterozygous translocation with two different translocation chromosomes. By the C-banding, one of the three translocation lines was identified, the translocation chromosome consisted of 7DL of wheat and a chromosome arm of L. mollis. In addition, wheat chromosome deletions were observed in some plants. In another cross combination involved in common wheat and T. aestivum-Th. intermedium addition line, two alien terminal non-Robertsonian translocation lines (WI-21 and WI-68) were identified from 69 F2 plants by C-banding and GISH, and the percentage of translocation line was 2.90%. By C-banding analysis, the translocation chromosomes involved in wheat chromosomes 3A and 4A in the two lines, respectively. These results indicate that inducing wheat alien translocation line by gametocidal chromosome and irradiated pollens all are efficient methods. PMID:14579529

Wang, Xian-Ping; Chu, Jing-Hua; Zhang, Xiang-Qi

2003-07-01

61

Chromosome translocations in wild populations of tetraploid emmer wheat in Israel and Turkey.  

PubMed

Translocation frequencies (as compared to the standard chromosome arrangement typified by that in 'Chinese Spring') in 9 or more genotypes from each of 15 populations of Triticum dicoccoides in Israel were determined. Data also were obtained from 2 genotypes of the southernmost population (Jaba). A single population from Turkey was also investigated. There were 119 genotypes with translocations in the sample of 171 genotypes investigated (70%). The frequency of translocations in different populations varied from 0.27 to 1.00, and all populations had 1 or more genotypes with one or more translocations. Some populations such as Qazrin appeared to be homogeneous for translocations, but most populations were heterogeneous. A sample of 17 genotypes from 12 of the populations were crossed with the Langdon D-genome disomic substitutions to determine the identity of the chromosomes involved in the translocations. There were nine genotypes with translocations and with the exception of a 2A/2B translocation, none of them involved the same chromosomes. The B-genome chromosomes were involved in translocations more frequently than the A-genome chromosomes. Translocation frequencies (TF) of the various populations were correlated with environmental variables, primarily with water availability and humidity, and possibly also with soil type. In general, TF was higher in peripheral populations in the ecologically heterogeneous frontiers of species distribution than in the central populations located in the catchment area of the upper Jordan valley. PMID:24169905

Joppa, L R; Nevo, E; Beiles, A

1995-10-01

62

Mechanisms Underlying Stage-1 TRPL Channel Translocation in Drosophila Photoreceptors  

PubMed Central

Background TRP channels function as key mediators of sensory transduction and other cellular signaling pathways. In Drosophila, TRP and TRPL are the light-activated channels in photoreceptors. While TRP is statically localized in the signaling compartment of the cell (the rhabdomere), TRPL localization is regulated by light. TRPL channels translocate out of the rhabdomere in two distinct stages, returning to the rhabdomere with dark-incubation. Translocation of TRPL channels regulates their availability, and thereby the gain of the signal. Little, however, is known about the mechanisms underlying this trafficking of TRPL channels. Methodology/Principal Findings We first examine the involvement of de novo protein synthesis in TRPL translocation. We feed flies cycloheximide, verify inhibition of protein synthesis, and test for TRPL translocation in photoreceptors. We find that protein synthesis is not involved in either stage of TRPL translocation out of the rhabdomere, but that re-localization to the rhabdomere from stage-1, but not stage-2, depends on protein synthesis. We also characterize an ex vivo eye preparation that is amenable to biochemical and genetic manipulation. We use this preparation to examine mechanisms of stage-1 TRPL translocation. We find that stage-1 translocation is: induced with ATP depletion, unaltered with perturbation of the actin cytoskeleton or inhibition of endocytosis, and slowed with increased membrane sterol content. Conclusions/Significance Our results indicate that translocation of TRPL out of the rhabdomere is likely due to protein transport, and not degradation/re-synthesis. Re-localization from each stage to the rhabdomere likely involves different strategies. Since TRPL channels can translocate to stage-1 in the absence of ATP, with no major requirement of the cytoskeleton, we suggest that stage-1 translocation involves simple diffusion through the apical membrane, which may be regulated by release of a light-dependent anchor in the rhabdomere.

Lieu, Minh-Ha; Vallejos, Maximiliano J.; Michael, Emily; Tsunoda, Susan

2012-01-01

63

Charged polymer membrane translocation  

NASA Astrophysics Data System (ADS)

We study the process of charged polymer translocation, driven by an external electric potential, through a narrow pore in a membrane. We assume that the number of polymer segments, m, having passed the entrance pore mouth, is a slow variable governing the translocation process. Outside the pore the probability that there is an end segment at the entrance pore mouth, is taken as the relevant parameter. In particular we derive an expression for the free energy as a function of m, F(m). F(m) is used in the Smoluchowski equation in order to obtain the flux of polymers through the pore. In the low voltage regime we find a thresholdlike behavior and exponential dependence on voltage. Above this regime the flux depends linearly on the applied voltage. At very high voltages the process is diffusion limited and the flux saturates to a constant value. The model accounts for all features of the recent experiments by Henrickson [et al.] [Phys. Rev. Lett. 85, 3057 (2000)] for the flux of DNA molecules through an alpha-hemolysin pore as a function of applied voltage.

Ambjornsson, T.; Apell, S. P.; Konkoli, Z.; Di Marzio, E. A.; Kasianowicz, J. J.

2002-08-01

64

Background Information  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Background Information ... These have been labeled to remove fluid from patients suffering from volume overload. ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

65

Autosomal Translocations Causing Male Sterility and Viable Aneuploidy in the Mouse  

Microsoft Academic Search

In previous experiments on the induction of translocations in the mouse tests were usually confined to the sons of treated animals. In the present experiment daughters of irradiated males were studied, with a view to finding the frequency of X-linked translocations and of autosomal aberrations causing male sterility. The treated males were given 600 rad X-rays to the hind part

Mary F. Lyon; R. Meredith

1966-01-01

66

Detection of chemical agents in the atmosphere by open-path FT-IR spectroscopy under conditions of background interference: I. High-frequency flashes.  

PubMed

Open-path FT-IR spectra were measured while fireworks were emitting smoke and incandescent particles into the infrared beam. These conditions were designed to simulate the appearance of smoke and explosions in a battlefield. Diethyl ether was used to simulate the vapor-phase spectra of G agents such as sarin. The measured interferograms were corrected by a high-pass filter and were rejected when interfering features were of such high frequency that they could not be removed by application of this filter. The concentration of diethyl ether was calculated correctly by partial least squares regression in the absence of fireworks but significant errors were encountered when the spectra of the oxide particles were not included in the calibration set. Target factor analysis allowed the presence of the analyte to be detected even when the incandescent particles were present in the beam. PMID:20401469

Shao, Limin; Roske, Christopher W; Griffiths, Peter R

2010-04-18

67

XP11.2 Translocation renal cell carcinoma: Clinical experience of Taipei Veterans General Hospital  

Microsoft Academic Search

BackgroundXp11.2 translocation renal cell carcinoma (RCC), a recently recognized distinct subtype of RCC, is characterized by various translocations, all involving the TFE3 transcription factor gene. These rare cancers occur predominantly in children and young adults and comprise about one-third of pediatric RCCs. In the present study, we review the clinical course of Xp11.2 translocation renal cell carcinoma in our institution.

Chia-Chen Hung; Chin-Chen Pan; Chih-Chieh Lin; Alex T. L. Lin; Kuang-Kuo Chen; Yen-Hwa Chang

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

Event distributions of polymer translocation  

NASA Astrophysics Data System (ADS)

We present event distributions for the polymer translocation obtained by extensive Langevin dynamics simulations. Such distributions have not been reported previously and they provide new understanding of the stochastic characteristics of the process. We extract at a high length scale resolution distributions of polymer segments that continuously traverse through a nanoscale pore. The obtained log-normal distributions together with the characteristics of polymer translocation suggest that it is describable as a multiplicative stochastic process. In spite of its clear out-of-equilibrium nature the forced translocation is surprisingly similar to the unforced case. We find forms for the distributions almost unaltered with a common cut-off length. We show that the individual short-segment and short-time movements inside the pore give the scaling relations ?˜N? and ?˜f-? for the polymer translocation.

Linna, R. P.; Kaski, K.

2012-04-01

70

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

71

Serological Markers for Inflammatory Bowel Disease in AIDS Patients with Evidence of Microbial Translocation  

Microsoft Academic Search

BackgroundBreakdown of the gut mucosal barrier during chronic HIV infection allows translocation of bacterial products such as lipopolysaccharides (LPS) from the gut into the circulation. Microbial translocation also occurs in inflammatory bowel disease (IBD). IBD serological markers are useful in the diagnosis of IBD and to differentiate between Crohn's disease (CD) and ulcerative colitis (UC). Here, we evaluate detection of

Anupa Kamat; Petronela Ancuta; Richard S. Blumberg; Dana Gabuzda; Derya Unutmaz

2010-01-01

72

Direct and Acclimatory Responses of Dark Respiration and Translocation to Temperature  

Microsoft Academic Search

Background and Aims Accounting for the acclimation of respiration of plants to temperature remains a major problem in analysis of carbon balances of plants and ecosystems. Translocation of carbohydrates out of leaves in the dark requires energy from respiration. In this study relationships between the responses of leaf respiration and translocation to temperature are examined. † Methods Direct and

JAMES A. B UNCE

2007-01-01

73

Downside risk of wildlife translocation.  

PubMed

Translocation has been used successfully by wildlife professionals to enhance or reintroduce populations of rare or extirpated wildlife, provide hunting or wildlife viewing opportunities, farm wild game, and reduce local human-wildlife conflicts. However, accidental and intentional translocations may have multiple unintended negative consequences, including increased stress and mortality of relocated animals, negative impacts on resident animals at release sites, increased conflicts with human interests, and the spread of diseases. Many wildlife professionals now question the practice of translocation, particularly in light of the need to contain or eliminate high profile, economically important wildlife diseases and because using this technique may jeopardize international wildlife disease management initiatives to control rabies in raccoons, coyotes, and foxes in North America. Incidents have been documented where specific rabies variants (Texas gray fox, canine variant in coyotes, and raccoon) have been moved well beyond their current range as a result of translocation, including the emergence of raccoon rabies in the eastern United States. Here, we review and discuss the substantial challenges of curtailing translocation in the USA, focusing on movement of animals by the public, nuisance wildlife control operators, and wildlife rehabilitators. PMID:18634483

Chipman, R; Slate, D; Rupprecht, C; Mendoza, M

2008-01-01

74

Three-Dimensional Genome Architecture Influences Partner Selection for Chromosomal Translocations in Human Disease  

PubMed Central

Chromosomal translocations are frequent features of cancer genomes that contribute to disease progression. These rearrangements result from formation and illegitimate repair of DNA double-strand breaks (DSBs), a process that requires spatial colocalization of chromosomal breakpoints. The “contact first” hypothesis suggests that translocation partners colocalize in the nuclei of normal cells, prior to rearrangement. It is unclear, however, the extent to which spatial interactions based on three-dimensional genome architecture contribute to chromosomal rearrangements in human disease. Here we intersect Hi-C maps of three-dimensional chromosome conformation with collections of 1,533 chromosomal translocations from cancer and germline genomes. We show that many translocation-prone pairs of regions genome-wide, including the cancer translocation partners BCR-ABL and MYC-IGH, display elevated Hi-C contact frequencies in normal human cells. Considering tissue specificity, we find that translocation breakpoints reported in human hematologic malignancies have higher Hi-C contact frequencies in lymphoid cells than those reported in sarcomas and epithelial tumors. However, translocations from multiple tissue types show significant correlation with Hi-C contact frequencies, suggesting that both tissue-specific and universal features of chromatin structure contribute to chromosomal alterations. Our results demonstrate that three-dimensional genome architecture shapes the landscape of rearrangements directly observed in human disease and establish Hi-C as a key method for dissecting these effects.

Mirny, Leonid A.

2012-01-01

75

HMGB1 cytoplasmic translocation in patients with acute liver failure  

PubMed Central

Background High-mobility group box 1 (HMGB1) is a late mediator of lethal systemic inflammation. Acute liver failure (ALF) has been shown to trigger systemic inflammation in clinical and animal studies. To evaluate the possibility of HMGB1 cytoplasmic translocation in ALF, we determined whether HMGB1 is released in hepatocytes and end organ in patients with liver failure/injury. Methods HepG2 cell were stimulated with LPS or TNF-?, the increase of HMGB1 extracellularly in the culture medium and intracellularly in various cellular fractions were determined by western blot or immunocytochemistry. To observe sub-cellular location of HMGB1 in hepatocytes, liver specimens were obtained from 6 patients with ALF caused by HBV infection, 10 patients with chronic viral hepatitis B, 6 healthy controls, as well as animals model of ALF by intraperitoneal administration of D-GalN (600 mg/kg) and LPS (0.5 mg/kg). Results In HepG2 cell culture, LPS or TNF actively induced HMGB1 cytoplasmic translocation and release in a time- and dose-dependent fashion. In animal model of ALF, cytoplasmic HMGB1 translocation was observed in hepatocyts as early as 3 hours post onset of ALF. In patients with ALF caused by HBV infection, cytoplasmic HMGB1 translocation was similarly observed in some hepatocytes of the liver specimen. Conclusions Cytoplasmic HMGB1 translocation may occur during ALF, which may potentially contribute to the pathogenesis of liver inflammatory diseases.

2011-01-01

76

Translocation. Incidental phenomenon or true pathology?  

PubMed Central

OBJECTIVE: This study was conducted to determine if reduction of early postburn endotoxemia influences the cytokine cascade, clinical manifestations of sepsis, and mortality rate. SUMMARY BACKGROUND DATA: Translocational endotoxemia has been demonstrated postburn in animals and humans. Endotoxin is known to induce the cytokine cascade, which leads to the clinical manifestations of sepsis. Whether reduction of postburn endotoxemia could influence the induction of cytokines has not been demonstrated. METHODS: In a prospective, randomized study, 76 burn patients were given polymyxin intravenously or served as control subjects. Polymyxin B was given intravenously for 1 week postburn in doses designed to neutralize circulating endotoxemia. RESULTS: In the polymyxin group, there was a statistically significant reduction in the plasma endotoxin concentration. There was, however, no reduction in the sepsis score or the interleukin-6 levels, and no differences in mortality rates were seen between the two groups. CONCLUSIONS: Early postburn translocational endotoxemia can be treated with anti-endotoxin agents such as polymyxin B. This, however, does not influence the cytokine cascade or the mortality rate. The systemic inflammatory response syndrome is caused by cytokine induction from the injury and is unaffected by a reduction in the plasma endotoxin concentration.

Munster, A M; Smith-Meek, M; Dickerson, C; Winchurch, R A

1993-01-01

77

Translocation renal cell carcinomas in adults: a single-institution experience.  

PubMed

Translocation renal cell carcinoma is a newly recognized subtype of renal cell carcinoma (RCC) with chromosomal translocations involving TFE3 (Xp11.2) or, less frequently, TFEB (6p21). Xp11 translocation RCC was originally described as a pediatric neoplasm representing 20% to 40% of pediatric RCCs, with a much lower frequency in the adult population. TFEB translocation RCC is very rare, with approximately 10 cases reported in the literature. Here, we describe the clinicopathologic features of adult translocation RCC from a single institution. Using tissue microarray, immunohistochemistry, cytogenetic examination, and fluorescence in situ hybridization, we identified 6 (?5%) cases of TFE3 translocation RCC and 1 (<1%) case of TFEB translocation RCC in 121 consecutive adult RCC cases between 2001 and 2009. Our results suggest that weak TFE3 staining of a significant proportion of RCC cases may be because of expression of the full-length TFE3 protein rather than the chimeric fusion protein resulting from chromosomal translocation. PMID:22446944

Zhong, Minghao; De Angelo, Patricia; Osborne, Lisa; Paniz-Mondolfi, Alberto E; Geller, Matthew; Yang, Youfeng; Linehan, W Marston; Merino, Maria J; Cordon-Cardo, Carlos; Cai, Dongming

2012-05-01

78

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

79

Linkage map construction involving a reciprocal translocation.  

PubMed

This paper is concerned with a novel statistical-genetic approach for the construction of linkage maps in populations obtained from reciprocal translocation heterozygotes of barley (Hordeum vulgare L.). Using standard linkage analysis, translocations usually lead to 'pseudo-linkage': the mixing up of markers from the chromosomes involved in the translocation into a single linkage group. Close to the translocation breakpoints recombination is severely suppressed and, as a consequence, ordering markers in those regions is not feasible. The novel strategy presented in this paper is based on (1) disentangling the "pseudo-linkage" using principal coordinate analysis, (2) separating individuals into translocated types and normal types and (3) separating markers into those close to and those more distant from the translocation breakpoints. The methods make use of a consensus map of the species involved. The final product consists of integrated linkage maps of the distal parts of the chromosomes involved in the translocation. PMID:21153624

Farré, A; Benito, I Lacasa; Cistué, L; de Jong, J H; Romagosa, I; Jansen, J

2010-12-14

80

Facilitated translocation of polypeptides through a single nanopore  

NASA Astrophysics Data System (ADS)

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 equipped 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 the 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

2010-11-01

81

Anomalous dynamics of polymer translocation  

NASA Astrophysics Data System (ADS)

We study the passage times of a translocating polymer of length N in three dimensions, while it passes through a narrow pore. We show that the behavior of the polymer stems from the polymer dynamics at the immediate vicinity of the pore --- in particular, the memory effects in the polymer chain tension imbalance across the pore. We take as a reaction coordinate the number s of the monomer residing in the pore. in the case of unbiased translocation, these memory effects cause the mobility of s to be anomalous diffusion for times up to the Rouse time N˜N^1+2? or Zimm time N˜N^3?, without or with hydrodynamics, respectively. Here, ? is the Flory exponent. Beyond this time, the dynamics becomes ordinary diffusion. As a consequence, the pore blockade time scales with length as ?d˜N^2+?. If a force of sufficient strength is pulling on one end, the pore blockade time scales as ?d˜N^2 in the absence of hydrodynamics. If a voltage is applied across the pore, which drives the charged polymer, the pore blockade time scales as ?d˜N^(1+2?)/(1+?) without, and ?d˜N^3?/(1+?) with hydrodynamics. In these cases, the pore blockade time decreases inversely with force and field strength, respectively. Our theoretical framework is substantiated with high-precision computer simulations. We will show that memory effects similar to those governing translocation, also play a role in the dynamics of dense polymer solutions and polymer melts.

Barkema, Gerard

2009-03-01

82

Glutamine deprivation facilitates tumour necrosis factor induced bacterial translocation in Caco-2 cells by depletion of enterocyte fuel substrate  

Microsoft Academic Search

Background and aims: Factors that induce luminal bacteria to cross the intestinal epithelium following injury remain poorly defined. The aim of this study was to investigate the interaction between glutamine metabolism, energy supply, and inflammatory mediators in determining the translocation of non-pathogenic bacteria across cultured enterocytes.Methods: The effect of tumour necrosis factor ? (TNF-?) on translocation of Escherichia coli C25

E C Clark; S D Patel; P R Chadwick; G Warhurst; A Curry; G L Carlson

2003-01-01

83

Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model  

Microsoft Academic Search

BACKGROUND: Experimental studies provide evidence that inhaled nanoparticles may translocate over the airspace epithelium and cause increased cellular inflammation. Little is known, however, about the dependence of particle size or material on translocation characteristics, inflammatory response and intracellular localization. RESULTS: Using a triple cell co-culture model of the human airway wall composed of epithelial cells, macrophages and dendritic cells we

Barbara Rothen-Rutishauser; Christian Mühlfeld; Fabian Blank; Claudia Musso; Peter Gehr

2007-01-01

84

Meiotic segregation of rare Robertsonian translocations: sperm analysis of three t(14q;22q) cases  

Microsoft Academic Search

BACKGROUND: The t(14;22) remains one of the rare Robertsonian translocations observed in human, with an occurrence estimated at 1.2%. Three cases of rare Robertsonian translocation t(14;22) were investigated for meiotic segregation in sperm samples from male carriers using the fluorescent in situ hybridization (FISH) procedure. The three carriers included two men with an abnormal semen analysis and one with normal

K. Moradkhani; J. Puechberty; S. Bhatt; P. Vago; L. Janny; G. Lefort; S. Hamamah; P. Sarda; F. Pellestor

2006-01-01

85

Translocation of Copolymers through a Nanopore  

NASA Astrophysics Data System (ADS)

Translocation of copolymers (AB, ABA, BAB, ABAB, random, etc.), consisting of hydrophilic (monomer A) and hydrophobic (monomer B) groups, threading a nanopore is studied by using a three-dimensional dynamic Monte Carlo simulation. We focus on the orientation of a copolymer, namely the monomer A enters the pore first or the monomer B first. We find that there are two characteristic translocation times and waiting time distributions associated with translocation of these copolymers.

Matsuyama, Akihiko; Ohno, Kyoko; Nishiono, Makoto

2013-02-01

86

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

87

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

88

A De Novo Case of Floating Chromosomal Polymorphisms by Translocation in Quasipaa boulengeri (Anura, Dicroglossidae)  

PubMed Central

Very few natural polymorphisms involving interchromosomal reciprocal translocations are known in amphibians even in vertebrates. In this study, thirty three populations, including 471 individuals of the spiny frog Quasipaa boulengeri, were karyotypically examined using Giemsa stain or FISH. Five different karyomorphs were observed. The observed heteromorphism was autosomal but not sex-related, as the same heteromorphic chromosomes were found both in males and females. Our results indicated that the variant karyotypes resulted from a mutual interchange occurring between chromosomes 1 and 6. The occurrence of a nearly whole-arm translocation between chromosome no. 1 and no. 6 gave rise to a high frequency of alternate segregation and probably resulted in the maintenance of the translocation polymorphisms in a few populations. The translocation polymorphism is explained by different frequencies of segregation modes of the translocation heterozygote during meiosis. Theoretically, nine karyomorphs should be investigated, however, four expected karyotypes were not found. The absent karyomorphs may result from recessive lethal mutations, position effects, duplications and deficiencies. The phylogenetic inference proved that all populations of Q. boulengeri grouped into a monophyletic clade. The mutual translocation likely evolved just once in this species and the dispersal of the one karyomorph (type IV) can explain the chromosomal variations among populations.

Qing, Liyan; Xia, Yun; Zheng, Yuchi; Zeng, Xiaomao

2012-01-01

89

A de novo case of floating chromosomal polymorphisms by translocation in Quasipaa boulengeri (Anura, Dicroglossidae).  

PubMed

Very few natural polymorphisms involving interchromosomal reciprocal translocations are known in amphibians even in vertebrates. In this study, thirty three populations, including 471 individuals of the spiny frog Quasipaa boulengeri, were karyotypically examined using Giemsa stain or FISH. Five different karyomorphs were observed. The observed heteromorphism was autosomal but not sex-related, as the same heteromorphic chromosomes were found both in males and females. Our results indicated that the variant karyotypes resulted from a mutual interchange occurring between chromosomes 1 and 6. The occurrence of a nearly whole-arm translocation between chromosome no. 1 and no. 6 gave rise to a high frequency of alternate segregation and probably resulted in the maintenance of the translocation polymorphisms in a few populations. The translocation polymorphism is explained by different frequencies of segregation modes of the translocation heterozygote during meiosis. Theoretically, nine karyomorphs should be investigated, however, four expected karyotypes were not found. The absent karyomorphs may result from recessive lethal mutations, position effects, duplications and deficiencies. The phylogenetic inference proved that all populations of Q. boulengeri grouped into a monophyletic clade. The mutual translocation likely evolved just once in this species and the dispersal of the one karyomorph (type IV) can explain the chromosomal variations among populations. PMID:23056254

Qing, Liyan; Xia, Yun; Zheng, Yuchi; Zeng, Xiaomao

2012-10-03

90

Translocation Capture Sequencing: A Method for High Throughput Mapping of Chromosomal Rearrangements  

PubMed Central

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.

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

2012-01-01

91

Haloarchaeal Protein Translocation via the Twin Arginine Translocation Pathway  

SciTech Connect

Protein transport across hydrophobic membranes that partition cellular compartments is essential in all cells. The twin arginine translocation (Tat) pathway transports proteins across the prokaryotic cytoplasmic membranes. Distinct from the universally conserved Sec pathway, which secretes unfolded proteins, the Tat machinery is unique in that it secretes proteins in a folded conformation, making it an attractive pathway for the transport and secretion of heterologously expressed proteins that are Sec-incompatible. During the past 7 years, the DOE-supported project has focused on the characterization of the diversity of bacterial and archaeal Tat substrates as well as on the characterization of the Tat pathway of a model archaeon, Haloferax volcanii, a member of the haloarchaea. We have demonstrated that H. volcanii uses this pathway to transport most of its secretome.

Pohlschroder Mechthild

2009-02-03

92

Complications associated with limited macular translocation  

Microsoft Academic Search

PURPOSE: To report the ocular complications associated with the limited macular translocation procedure.METHODS: Retrospective review of 153 consecutive eyes of 151 patients that had the limited macular translocation procedure for subfoveal choroidal neovascularization between April 1996 and February 1999. The major study variables investigated included the incidence of specific ocular complications and their impact on visual acuity at 3 months

Gildo Y Fujii; Dante J Pieramici; Mark S Humayun; Andrew P Schachat; Sandra M Reynolds; Michele Melia; Eugene De Juan

2000-01-01

93

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

94

Translocations among Antibody Genes in Human Cancer  

Microsoft Academic Search

The characteristic chromosomal translocations that occur in certain human malignancies offer opportunities to understand how two gene systems can affect one another when they are accidentally juxtaposed. In the case of Burkitt lymphoma, such a translocation joins the cellular oncogene, c-myc, to a region encoding one of the immunoglobulin genes. In at least one example, the coding sequence of the

Philip Leder; Jim Battey; Gilbert Lenoir; Christopher Moulding; William Murphy; Huntington Potter; Timothy Stewart; Rebecca Taub

1983-01-01

95

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...types of translocations: (A) Translocations between non-homologous chromosomes in which at least one of the breaks occurs close...chain of four chromosomes held together by chiasmata in paired homologous regions. Some translocation carriers can be identified...

2010-07-01

96

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...types of translocations: (A) Translocations between non-homologous chromosomes in which at least one of the breaks occurs close...chain of four chromosomes held together by chiasmata in paired homologous regions. Some translocation carriers can be identified...

2009-07-01

97

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

2013-08-14

98

Earth's Background Free Oscillations  

NASA Astrophysics Data System (ADS)

Earth's background free oscillations, known as Earth's hum, were discovered in 1998. Excited modes of the oscillations are almost exclusively fundamental spheroidal and toroidal modes from 2 to 20 mHz. Seasonal variations in the source distribution suggest that the dominant sources are ocean infragravity waves in the shallow and deep oceans. A probable excitation mechanism is random shear traction acting on the sea bottom owing to linear topographic coupling of the infragravity waves. Excitation by pressure sources on Earth's surface is also significant for a frequency below 5 mHz. A possible pressure source is atmospheric turbulence, which can cause observed resonant oscillations between the solid modes and atmospheric acoustic modes.

Nishida, Kiwamu

2013-05-01

99

Relative rates at which dominant-lethal mutations and heritable translocations are induced by alkylating chemicals in postmeiotic male germ cells of mice  

Microsoft Academic Search

There is a close relationship between the rates at which dominant lethal mutations and heritable translocations are induced by ethyl methanesulfonate (EMS) or triethylenemelamine (TEM) in male postmeiotic germ cells. This relationship does not hold for isopropyl methanesulfonate (IMS), which induced only negigible frequencies of heritable translocations at doses that induced high levels of dominant lethal mutations. Nor does IMS

W. M. Generoso; S. W. Huff; K. T. Cain

1979-01-01

100

The unfolding story of anthrax toxin translocation  

PubMed Central

Summary The essential cellular functions of secretion and protein degradation require a molecular machine to unfold and translocate proteins either across a membrane or into a proteolytic complex. Protein translocation is also critical for microbial pathogenesis, namely bacteria can use translocase channels to deliver toxic proteins into a target cell. Anthrax toxin (Atx), a key virulence factor secreted by Bacillus anthracis, provides a robust biophysical model to characterize transmembrane protein translocation. Atx is comprised of three proteins: the translocase component, protective antigen (PA); and two enzyme components, lethal factor (LF) and edema factor (EF). Atx forms an active holotoxin complex containing a ring-shaped PA oligomer bound to multiple copies of LF and EF. These complexes are endocytosed into mammalian host cells, where PA forms a protein-conducting translocase channel. The proton motive force unfolds and translocates LF and EF through the channel. Recent structure and function studies have shown that LF unfolds during translocation in a force-dependent manner via a series of metastable intermediates. Polypeptide-binding clamps located throughout the PA channel catalyze substrate unfolding and translocation by stabilizing unfolding intermediates through the formation of a series of interactions with various chemical groups and ?-helical structure presented by the unfolding polypeptide during translocation.

Thoren, Katie L.; Krantz, Bryan A.

2011-01-01

101

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

102

Computer simulations and theory of protein translocation.  

PubMed

The translocation of proteins through pores is central to many biological phenomena, such as mitochondrial protein import, protein degradation, and delivery of protein toxins to their cytosolic targets. Because proteins typically have to pass through constrictions that are too narrow to accommodate folded structures, translocation must be coupled to protein unfolding. The simplest model that accounts for such co-translocational unfolding assumes that both translocation and unfolding are accomplished by pulling on the end of the polypeptide chain mechanically. In this Account, we describe theoretical studies and computer simulations of this model and discuss how the time scales of translocation depend on the pulling force and on the protein structure. Computationally, this is a difficult problem because biologically or experimentally relevant time scales of translocation are typically orders of magnitude slower than those accessible by fully atomistic simulations. For this reason, we explore one-dimensional free energy landscapes along suitably defined translocation coordinates and discuss various approaches to their computation. We argue that the free energy landscape of translocation is often bumpy because confinement partitions the protein's configuration space into distinct basins of attraction separated by large entropic barriers. Favorable protein-pore interactions and nonnative interactions within the protein further contribute to the complexity. Computer simulations and simple scaling estimates show that forces of just 2-6 pN are often sufficient to ensure transport of unstructured polypeptides, whereas much higher forces are typically needed to translocate folded protein domains. The unfolding mechanisms found from simulations of translocation are different from those observed in the much better understood case of atomic force microscopy (AFM) pulling studies, in which proteins are unraveled by stretching them between their N- and C-termini. In contrast to AFM experiments, single-molecule experimental studies of protein translocation have just started to emerge. We describe one example of a collaborative study, in which dwell times of beta-hairpin-forming peptides inside the alpha-hemolysin pore were both measured experimentally and estimated using computer simulations. Analysis of the simulated trajectories has explained the experimental finding that more stable hairpins take, on the average, longer to traverse the pore. Despite the insight we have gained, the general relationship between the structure of proteins and their resistance to mechanically driven co-translocational unfolding remains poorly understood. Future theoretical progress likely will be made in conjunction with single-molecule experiments and will require realistic models to account for specific protein-pore interactions and for solvent effects. PMID:19072704

Makarov, Dmitrii E

2009-02-17

103

Markovian description of unbiased polymer translocation  

NASA Astrophysics Data System (ADS)

We perform, with the help of cloud computing resources, extensive Langevin simulations which provide compelling evidence in favor of a general Markovian framework for unbiased three-dimensional polymer translocation. Our statistical analysis consists of careful evaluations of (i) two-point correlation functions of the translocation coordinate and (ii) the empirical probabilities of complete polymer translocation (taken as a function of the initial number of monomers on a given side of the membrane). We find good agreement with predictions derived from the Markov chain approach recently addressed in the literature by the present authors.

Mondaini, Felipe; Moriconi, L.

2012-10-01

104

[Macular translocation--first experience].  

PubMed

The age related macular degeneration (ARMD) is the most common cause of the central visual acuity loss in persons of age more than 60 years in the well developed countries. Rotation of the macula is nowadays a progressive method of choice of treatment of the exsudative form of ARMD. The aim of this surgical technique is to relocate the neuroretinal epithelium of the central region of the retina to a position situated outside the border of the subfoveolar lesion. Three eyes of three patients (2 woman and one man) were operated on during the period between March and May 2001 at the Department of Ophthalmology of the School of Medicine, Charles University in Pilsen. The method used was the scleral imbrication, which belongs to methods designated as "limited translocation". The mean age of the patients was 62 years and the follow up period was 2 years. After the surgery the relocation of the fovea was observed in all three eyes. In two eyes, the postoperative period was complicated by tractional retinal detachment that occurred three weeks after the surgery as a consequence of progressive proliferative vitreoretinopathy (PVR). Both eyes with the retinal detachment were re-operated. In both of them, the repeated pars plana vitrectomy, epiretinal membranes removal with relaxing retinectomy was performed and after maximal mobilization of the retina, the silicone oil implantation followed. In the second patient, the postoperative period was complicated by elevation of the intraocular pressure and a radial retinal fold running from the encircling buckle indentation up to the macula. Slightly improved function was noticed only in the first patient after following cataract surgery with intraocular lens implantation. In the two other eyes, as noticed at the last follow up check, the postoperative complications caused severe decrease of the central visual acuity although the retina remained attached. Macular translocation procedure is in stage of development and its surgical techniques are being further modified. The risk of postoperative complications with profound loss of central visual acuity corresponds to the level of the technical difficulty and extent of surgical intervention. PMID:15369259

Dolezalová, J; Rusnák, S

2004-07-01

105

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

106

Severe Hypospadias Associated with Robertsonian Translocation  

Microsoft Academic Search

In this study, we report a 3-year-old boy with severe scrotal hypospadias with Robertsonian translocation [45,XY,t(13q;14q)]. The patient was born at term with a low birth weight and hypospadias. There was no endocrinological abnormality. His father also has a balanced 13–14 Robertsonian translocation. Two-stage hypospadias repair was carried out. The presence of this chromosomal anomaly and hypospadias are unique to

Nizamettin Kilic; Emin Balkan; Halil Saglam; Tahsin Yakut; Hasan Dogruyol

2005-01-01

107

Ratcheting up protein translocation with anthrax toxin  

PubMed Central

Energy-consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine-catalyzed biopolymer transport have revealed that these machines are equipped with molecular parts, including adjustable clamps, levers, and adaptors, which interact favorably with substrate polypeptides. Biological nanomachines that catalyze protein transport, known as translocases, often require that their substrate proteins unfold before translocation. An unstructured protein chain is likely entropically challenging to bind, push, or pull in a directional manner, especially in a way that produces an unfolding force. A number of ingenious solutions to this problem are now evident in the anthrax toxin system, a model used to study protein translocation. Here we highlight molecular ratchets and current research on anthrax toxin translocation. A picture is emerging of proton-gradient-driven anthrax toxin translocation, and its associated ratchet mechanism likely applies broadly to other systems. We suggest a cyclical thermodynamic order-to-disorder mechanism (akin to a heat-engine cycle) is central to underlying protein translocation: peptide substrates nonspecifically bind to molecular clamps, which possess adjustable affinities; polypeptide substrates compress into helical structures; these clamps undergo proton-gated switching; and the substrate subsequently expands regaining its unfolded state conformational entropy upon translocation.

Feld, Geoffrey K; Brown, Michael J; Krantz, Bryan A

2012-01-01

108

Translocation of imperiled species under changing climates.  

PubMed

Conservation translocation of species varies from restoring historic populations to managing the relocation of imperiled species to new locations. We review the literature in three areas--translocation, managed relocation, and conservation decision making--to inform conservation translocation under changing climates. First, climate change increases the potential for conflict over both the efficacy and the acceptability of conservation translocation. The emerging literature on managed relocation highlights this discourse. Second, conservation translocation works in concert with other strategies. The emerging literature in structured decision making provides a framework for prioritizing conservation actions--considering many possible alternatives that are evaluated based on expected benefit, risk, and social-political feasibility. Finally, the translocation literature has historically been primarily concerned with risks associated with the target species. In contrast, the managed relocation literature raises concerns about the ecological risk to the recipient ecosystem. Engaging in a structured decision process that explicitly focuses on stakeholder engagement, problem definition and specification of goals from the outset will allow creative solutions to be developed and evaluated based on their expected effectiveness. PMID:23574620

Schwartz, Mark W; Martin, Tara G

2013-04-10

109

Translocation of polymers in a lattice model.  

PubMed

Voltage-driven polymer translocation is studied by means of a stochastic lattice model. The model incorporates voltage drop over the membrane as a bias in the hopping rate through the pore and exhibits the two main ingredients of the translocation process: driven motion through the pore and diffusive supply of chain length towards the pore on the cis-side and the drift away from the pore on the trans-side. The translocation time is either bias limited or diffusion limited. In the bias-limited regime the translocation time is inversely proportional to the voltage drop over the membrane. In the diffusion-limited regime the translocation time is independent of the applied voltage, but it is rather sensitive to the motion rules of the model. We find that the whole regime is well described by a single curve determined by the initial slope and the saturation value. The dependence of these parameters on the length of the chain, the motion rules and the repton statistics are established. Repulsion of reptons as well as the increase of chain length decrease the throughput of the polymer through the pore. As for free polymers, the inclusion of a mechanism for hernia creations/annihilations leads to the cross-over from Rouse-like behaviour to reptation. For the experimentally most relevant case (Rouse dynamics) the bimodal power law dependence of the translocation time on the chain length is found. PMID:22699389

Zurek, S; Ko?mider, M; Drzewi?ski, A; van Leeuwen, J M J

2012-06-15

110

Ratcheting up protein translocation with anthrax toxin.  

PubMed

Energy-consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine-catalyzed biopolymer transport have revealed that these machines are equipped with molecular parts, including adjustable clamps, levers, and adaptors, which interact favorably with substrate polypeptides. Biological nanomachines that catalyze protein transport, known as translocases, often require that their substrate proteins unfold before translocation. An unstructured protein chain is likely entropically challenging to bind, push, or pull in a directional manner, especially in a way that produces an unfolding force. A number of ingenious solutions to this problem are now evident in the anthrax toxin system, a model used to study protein translocation. Here we highlight molecular ratchets and current research on anthrax toxin translocation. A picture is emerging of proton-gradient-driven anthrax toxin translocation, and its associated ratchet mechanism likely applies broadly to other systems. We suggest a cyclical thermodynamic order-to-disorder mechanism (akin to a heat-engine cycle) is central to underlying protein translocation: peptide substrates nonspecifically bind to molecular clamps, which possess adjustable affinities; polypeptide substrates compress into helical structures; these clamps undergo proton-gated switching; and the substrate subsequently expands regaining its unfolded state conformational entropy upon translocation. PMID:22374876

Feld, Geoffrey K; Brown, Michael J; Krantz, Bryan A

2012-03-30

111

Translocation of ?-helix chains through a nanopore  

NASA Astrophysics Data System (ADS)

The translocation of ?-helix chains through a nanopore is studied through Langevin dynamics simulations. The ?-helix chains exhibit several different characteristics about their average translocation times and the ?-helix structures when they transport through the nanopores under the driving forces. First, the relationship between average translocation times ? and the chain length N satisfies the scaling law, ?~N?, and the scaling exponent ? depends on the driving force f for the small forces while it is close to the Flory exponent (?) in the other force regions. For the chains with given chain lengths, it is observed that the dependence of the average translocation times can be expressed as ?~f-1/2 for the small forces while can be described as ?~f in the large force regions. Second, for the large driving force, the average number of ?-helix structures Nh decreases first and then increases in the translocation process. The average waiting time of each bead, especially of the first bead, is also dependent on the driving forces. Furthermore, an elasticity spring model is presented to reasonably explain the change of the ?-helix number during the translocation and its elasticity can be locally damaged by the large driving forces. Our results demonstrate the unique behaviors of ?-helix chains transporting through the pores, which can enrich our insights into and knowledge on biopolymers transporting through membranes.

Yang, Zhiyong; Li, Shiben; Zhang, Linxi; Ur Rehman, Ateeq; Liang, Haojun

2010-10-01

112

Cosmic microwave background theory.  

PubMed

A long-standing goal of theorists has been to constrain cosmological parameters that define the structure formation theory from cosmic microwave background (CMB) anisotropy experiments and large-scale structure (LSS) observations. The status and future promise of this enterprise is described. Current band-powers in -space are consistent with a DeltaT flat in frequency and broadly follow inflation-based expectations. That the levels are approximately (10(-5))2 provides strong support for the gravitational instability theory, while the Far Infrared Absolute Spectrophotometer (FIRAS) constraints on energy injection rule out cosmic explosions as a dominant source of LSS. Band-powers at 100 suggest that the universe could not have re-ionized too early. To get the LSS of Cosmic Background Explorer (COBE)-normalized fluctuations right provides encouraging support that the initial fluctuation spectrum was not far off the scale invariant form that inflation models prefer: e.g., for tilted Lambda cold dark matter sequences of fixed 13-Gyr age (with the Hubble constant H0 marginalized), ns = 1.17 +/- 0.3 for Differential Microwave Radiometer (DMR) only; 1.15 +/- 0.08 for DMR plus the SK95 experiment; 1.00 +/- 0.04 for DMR plus all smaller angle experiments; 1.00 +/- 0.05 when LSS constraints are included as well. The CMB alone currently gives weak constraints on Lambda and moderate constraints on Omegatot, but theoretical forecasts of future long duration balloon and satellite experiments are shown which predict percent-level accuracy among a large fraction of the 10+ parameters characterizing the cosmic structure formation theory, at least if it is an inflation variant. PMID:9419321

Bond, J R

1998-01-01

113

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

114

Somatic inactivation of Tp53 in hematopoietic stem cells or thymocytes predisposes mice to thymic lymphomas with clonal translocations.  

PubMed

TP53 protects cells from transformation by responding to stresses including aneuploidy and DNA double-strand breaks (DSBs). TP53 induces apoptosis of lymphocytes with persistent DSBs at antigen receptor loci and other genomic loci to prevent these lesions from generating oncogenic translocations. Despite this critical function of TP53, germline Tp53(-/-) mice succumb to immature T-cell (thymic) lymphomas that exhibit aneuploidy and lack clonal translocations. However, Tp53(-/-) mice occasionally develop B lineage lymphomas and Tp53 deletion in pro-B cells causes lymphomas with oncogenic immunoglobulin (Ig) locus translocations. In addition, human lymphoid cancers with somatic TP53 inactivation often harbor oncogenic IG or T-cell receptor (TCR) locus translocations. To determine whether somatic Tp53 inactivation unmasks translocations or alters the frequency of B lineage tumors in mice, we generated and analyzed mice with conditional Tp53 deletion initiating in hematopoietic stem cells (HSCs) or in lineage-committed thymocytes. Median tumor-free survival of each strain was similar to the lifespan of Tp53(-/-) mice. Mice with HSC deletion of Tp53 predominantly succumbed to thymic lymphomas with clonal translocations not involving Tcr loci; however, these mice occasionally developed mature B-cell lymphomas that harbored clonal Ig translocations. Deletion of Tp53 in thymocytes caused thymic lymphomas with aneuploidy and/or clonal translocations, including oncogenic Tcr locus translocations. Our data demonstrate that the developmental stage of Tp53 inactivation affects karyotypes of lymphoid malignancies in mice where somatic deletion of Tp53 initiating in thymocytes is sufficient to cause thymic lymphomas with oncogenic translocations. PMID:24036547

Demicco, Amy; Yang-Iott, Katherine; Bassing, Craig H

2013-09-09

115

Measuring peptide translocation into large unilamellar vesicles  

PubMed Central

There is an active interest in peptides that readily cross cell membranes without the assistance of cell membrane receptors1. Many of these are referred to as cell-penetrating peptides, which are frequently noted for their potential as drug delivery vectors1-3. Moreover, there is increasing interest in antimicrobial peptides that operate via non-membrane lytic mechanisms4,5, particularly those that cross bacterial membranes without causing cell lysis and kill cells by interfering with intracellular processes6,7. In fact, authors have increasingly pointed out the relationship between cell-penetrating and antimicrobial peptides1,8. A firm understanding of the process of membrane translocation and the relationship between peptide structure and its ability to translocate requires effective, reproducible assays for translocation. Several groups have proposed methods to measure translocation into large unilamellar lipid vesicles (LUVs).9-13 LUVs serve as useful models for bacterial and eukaryotic cell membranes and are frequently used in peptide fluorescent studies14,15. Here, we describe our application of the method first developed by Matsuzaki and co-workers to consider antimicrobial peptides, such as magainin and buforin II16,17. In addition to providing our protocol for this method, we also present a straightforward approach to data analysis that quantifies translocation ability using this assay. The advantages of this translocation assay compared to others are that it has the potential to provide information about the rate of membrane translocation and does not require the addition of a fluorescent label, which can alter peptide properties18, to tryptophan-containing peptides. Briefly, translocation ability into lipid vesicles is measured as a function of the Foster Resonance Energy Transfer (FRET) between native tryptophan residues and dansyl phosphatidylethanolamine when proteins are associated with the external LUV membrane (Figure 1). Cell-penetrating peptides are cleaved as they encounter uninhibited trypsin encapsulated with the LUVs, leading to disassociation from the LUV membrane and a drop in FRET signal. The drop in FRET signal observed for a translocating peptide is significantly greater than that observed for the same peptide when the LUVs contain both trypsin and trypsin inhibitor, or when a peptide that does not spontaneously cross lipid membranes is exposed to trypsin-containing LUVs. This change in fluorescence provides a direct quantification of peptide translocation over time.

Spinella, Sara A.; Nelson, Rachel B.; Elmore, Donald E.

2012-01-01

116

Gravitational wave background in inflationary models  

NASA Astrophysics Data System (ADS)

The generation of a gravitational wave (GW) background is a generic feature of inflationary models. This background, of quantum origin, covers a huge range of frequencies and is undistinguishable today on large cosmological scales from a classical stochastic background. We review some of its properties in different models including more sophisticated Broken Scale Invariance (BSI) models. .

Polarski, David

2001-02-01

117

Chemical mutagenesis testing in Drosophila. I. Comparison of positive and negative control data for sex-linked recessive lethal mutations and reciprocal translocations in three laboratories  

SciTech Connect

As part of the validation phase of the Drosophila melanogaster segment of the National Toxicology Program, a comparison has been made of positive and negative controls for sex-linked recessive lethal mutations and reciprocal translocations from three laboratories. This comparison involves approximately 700,000 spontaneous recessive lethal mutation tests, 70,000 spontaneous translocation tests, and screens for genetic damage induced by N-nitrosodimethylamine and ..beta..-propiolactone. Spontaneous frequencies for lethal mutations and translocations were homogeneous in the laboratories regardless of solvent or broods sampled. Inhomogeneity was observed in induced frequencies among laboratories, but the variation was no greater than that found within a laboratory.

Woodruff, R.C.; Mason, J.M.; Valencia, R.; Zimmering, S.

1984-01-01

118

Serotonin transporter (SERT) and translocator protein (TSPO) expression in the obese ob\\/ob mouse  

Microsoft Academic Search

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

Gino Giannaccini; Laura Betti; Lionella Palego; Andrea Pirone; Lara Schmid; Mario Lanza; Laura Fabbrini; Caterina Pelosini; Margherita Maffei; Ferruccio Santini; Aldo Pinchera; Antonio Lucacchini

2011-01-01

119

Chromosome territories, X;Y translocation and Premature Ovarian Failure: is there a relationship?  

Microsoft Academic Search

BACKGROUND: Premature ovarian failure (POF) is a secondary hypergonadotrophic amenorrhea occurring before the age of 40 and affecting 1-3% of females. Chromosome anomalies account for 6-8% of POF cases, but only few cases are associated with translocations involving X and Y chromosomes. This study shows the cytogenetic and molecular analysis of a POF patient came to our attention as she

Sara Lissoni; Simona Baronchelli; Nicoletta Villa; Valeria Lucchini; Enrico Betri; Pietro Cavalli; Leda Dalprà

2009-01-01

120

Translocation of Inhaled Ultrafine Manganese Oxide Particles to the Central Nervous System  

Microsoft Academic Search

BACKGROUND: Studies in monkeys with intranasally instilled gold ultrafine particles (UFPs; < 100 nm) and in rats with inhaled carbon UFPs suggested that solid UFPs deposited in the nose travel along the olfactory nerve to the olfactory bulb. METHODS: To determine if olfactory translocation occurs for other solid metal UFPs and assess potential health effects, we exposed groups of rats

Alison Elder; Robert Gelein; Vanessa Silva; Tessa Feikert; Lisa Opanashuk; Janet Carter; Russell Potter; Andrew Maynard; Yasuo Ito; Jacob Finkelstein; Günter Oberdörster

2006-01-01

121

Extragalactic Background Radiation  

NASA Astrophysics Data System (ADS)

Contents; Preface; List of participants; 1. Introduction P. J. E. Peebles; 2. Extragalactic gamma-ray background N. Gehrels and C. Cheung; 3. The X-ray background (observations) G. Zamorani; 4. Extragalactic ultraviolet background radiation R. C. Henry and J. Murthy; 5. Ultraviolet background (theory) P. Jakobsen; 6. The optical extragalactic background radiation J. A. Tyson; 7. Infrared background (observations) M. G. Hauser; 8. The infrared background (theory) C. J. Lonsdale; 9. Microwave background radiation (observations) J. C. Mather; 10. Detection of degree scale anisotropy P. M. Lubin; 11. Cosmic microwave background anisotropies and structure formation in the universe N. Vittorio; The radio background emission - the long and short of it M. S. Longair; 13. The radio background: radio-loud galaxies at high and low redshifts J. A. Peacock; 14. Conference summary M. J. Rees.

Calzetti, Daniela; Livio, Mario; Madau, Piero

1995-01-01

122

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

123

Chromosomal translocations are guided by the spatial organization of the genome  

PubMed Central

SUMMARY The extent to which the three dimensional organization of the genome contributes to chromosomal translocations is an important question in cancer genomics. We now have generated a high resolution Hi-C spatial organization map of the G1-arrested mouse pro-B cell genome and mapped translocations from target DNA double strand breaks (DSBs) within it via high throughput genome-wide translocation sequencing. RAG endonuclease-cleaved antigen-receptor loci are dominant translocation partners for target DSBs regardless of genomic position, reflecting high frequency DSBs at these loci and their co-localization in a fraction of cells. To directly assess spatial proximity contributions, we normalized genomic DSBs via ionizing-radiation. Under these conditions, translocations were highly enriched in cis along single chromosomes containing target DSBs and within other chromosomes and sub-chromosomal domains in a manner directly related to pre-existing spatial proximity. Our studies reveal the power of combining two high-throughput genomic methods to address long-standing questions in cancer biology.

Zhang, Yu; McCord, Rachel Patton; Ho, Yu-Jui; Lajoie, Bryan R.; Hildebrand, Dominic G.; Simon, Aline C.; Becker, Michael S.; Alt, Frederick W.; Dekker, Job

2012-01-01

124

The 3q27 and 18q21 translocations for follicular lymphoma and diffuse large B-cell lymphoma in the rituximab era.  

PubMed

The 3q27 and 18q21 chromosomal translocations are major hallmarks in B-cell lymphoma. We aimed to determine the frequencies of these translocations in follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) and to evaluate their prognostic impact in the rituximab era. This study included 98 FL and 93 DLBCL patients whose abnormal karyotypes had been detected using G-banding. Patients uniformly underwent R-CHOP therapy : doxorubicin, cyclophosphamide, vincristine, prednisolone, and rituximab ; survivors were followed up for 29 months (median). The 3q27 and 18q21 translocations were detected in 14 and 77 FL patients and 14 and 22 DLBCL patients, respectively. Overall survival (OS) and progression-free survival (PFS) did not differ significantly between the groups with 3q27, 18q21, concurrent 3q27 and 18q21 translocations, and other chromosomal abnormalities for FL and DLBCL. There were no significant differences in OS and PFS between patients with 3q27 translocation-positive FL and those with 3q27 translocation-positive DLBCL or between the patients with 18q21 translocation-positive FL and those with 18q21 translocation-positive DLBCL. The presence of 3q27 and 18q21 translocations did not correlate with the clinical outcomes of FL or DLBCL patients following R-CHOP treatment. PMID:23995106

Watanabe, Reina; Tomita, Naoto; Matsumoto, Chihiro; Hattori, Yukako; Matsuura, Shiro; Takasaki, Hirotaka; Hashimoto, Chizuko; Fujita, Hiroyuki; Fujisawa, Shin; Ishigatsubo, Yoshiaki

2013-01-01

125

Frequency Spectrum.  

National Technical Information Service (NTIS)

Uses a pictorial representation of the frequency spectrum to identify power frequencies, audio frequencies, radio frequencies, VhF, UhF, and microwaves. Given a specific wavelength, calculates the frequency. Given either frequency or wavelength, calculate...

1994-01-01

126

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

2012-04-25

127

Translocation pathways for inhaled asbestos fibers.  

PubMed

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 pulmonary lymph flow (primary translocation) wherefrom they can reach the blood stream and subsequently distribute to the whole body (secondary translocation). Primary translocation across the visceral pleura and towards pulmonary capillaries may also occur if the asbestos-induced lung inflammation increases pulmonary interstitial pressure so as to reverse the trans-mesothelial and trans-endothelial pressure gradients. Secondary translocation to the pleural space may occur via the physiological route of pleural fluid formation across the parietal pleura; fibers accumulation in parietal pleura stomata (black spots) reflects the role of parietal lymphatics in draining pleural fluid. Asbestos fibers are found in all organs of subjects either occupationally exposed or not exposed to asbestos. Fibers concentration correlates with specific conditions of interstitial fluid dynamics, in line with the notion that in all organs microvascular filtration occurs from capillaries to the extravascular spaces. Concentration is high in the kidney (reflecting high perfusion pressure and flow) and in the liver (reflecting high microvascular permeability) while it is relatively low in the brain (due to low permeability of blood-brain barrier). Ultrafine fibers (length < 5 mum, diameter < 0.25 mum) can travel larger distances due to low steric hindrance (in mesothelioma about 90% of fibers are ultrafine). Fibers translocation is a slow process developing over decades of life: it is aided by high biopersistence, by inflammation-induced increase in permeability, by low steric hindrance and by fibers motion pattern at low Reynolds numbers; it is hindered by fibrosis that increases interstitial flow resistances. PMID:18218073

Miserocchi, G; Sancini, G; Mantegazza, F; Chiappino, Gerolamo

2008-01-24

128

Pregnancy outcome in carriers of Robertsonian translocations.  

PubMed

Robertsonian translocation carriers are at increased risk for infertility, spontaneous abortions, or chromosomally unbalanced offspring. Reproductive counseling of these carriers is challenging. We performed a retrospective analysis of all prenatal diagnoses from Robertsonian translocation carriers during the time period January 1, 1992 through December 31, 2007. Data on the carriers and the results of their prenatal analyses were retrieved as well as data on their previous pregnancies. We identified 28 female and 20 male carriers of Robertsonian translocations and results on 79 prenatal samples were obtained. Among female carriers, 10.3% of chorionic villus sampling and 5.9% of amniocentesis results were unbalanced, whereas for male carriers, this was 3.6% and 0%, respectively. When considering all pregnancies involving carriers, 52.7% of those to female carriers and 61.8% of those to male carriers led to the birth of a healthy child. Male carriers in whom the translocation was ascertained because of infertility or recurrent miscarriages appear to be at higher risk, whereas carriers in whom ascertainment was because of a family history are at lower risk. We conclude that pregnancies of Robertsonian translocation carriers are at increased risk for chromosomal imbalance, and prenatal chromosomal testing should be discussed. More than half of the pregnancies led to the birth of a healthy child, but prediction of which couples will be successful in obtaining a pregnancy with or without assisted reproductive technologies and/or embryo selection remains difficult. The reason for ascertainment of the translocation should be taken into account when counseling these couples. The possibility of preimplantation genetic diagnosis should also be discussed with the couples. PMID:21910218

Keymolen, Kathelijn; Van Berkel, Kim; Vorsselmans, Anniek; Staessen, Catherine; Liebaers, Inge

2011-09-09

129

Doppler translocation and orbit relaxation techniques  

NASA Astrophysics Data System (ADS)

Satellite Doppler observations made in the translocation mode and processed by short arc and orbit relaxation techniques can lead to substantial improvements in relative positioning accuracies over those achieved by individual position determinations. The assessment of the relative merits of different mathematical solution models is a difficult task which can be solved by comparing the models to an 'absolute' standard. This has been done by using satellite Doppler observations made at nine stations forming part of the Edinburgh-Malvern-Dover precise traverse. The Doppler data obtained along this traverse in the translocation mode were processed by the new Nottingham orbit relaxation program as well as by other commercially available short arc programs.

Ashkenazi, V.; Sykes, R. M.

1980-01-01

130

Hyaluronan synthase mediates dye translocation across liposomal membranes  

PubMed Central

Background Hyaluronan (HA) is made at the plasma membrane and secreted into the extracellular medium or matrix by phospolipid-dependent hyaluronan synthase (HAS), which is active as a monomer. Since the mechanism by which HA is translocated across membranes is still unresolved, we assessed the presence of an intraprotein pore within HAS by adding purified Streptococcus equisimilis HAS (SeHAS) to liposomes preloaded with the fluorophore Cascade Blue (CB). Results CB translocation (efflux) was not observed with mock-purified material from empty vector control E. coli membranes, but was induced by SeHAS, purified from membranes, in a time- and dose-dependent manner. CB efflux was eliminated or greatly reduced when purified SeHAS was first treated under conditions that inhibit enzyme activity: heating, oxidization or cysteine modification with N-ethylmaleimide. Reduced CB efflux also occurred with SeHAS K48E or K48F mutants, in which alteration of K48 within membrane domain 2 causes decreased activity and HA product size. The above results used liposomes containing bovine cardiolipin (BCL). An earlier study testing many synthetic lipids found that the best activating lipid for SeHAS is tetraoleoyl cardiolipin (TO-CL) and that, in contrast, tetramyristoyl cardiolipin (TM-CL) is an inactivating lipid (Weigel et al, J. Biol. Chem. 281, 36542, 2006). Consistent with the effects of these CL species on SeHAS activity, CB efflux was more than 2-fold greater in liposomes made with TO-CL compared to TM-CL. Conclusions The results indicate the presence of an intraprotein pore in HAS and support a model in which HA is translocated to the exterior by HAS itself.

2012-01-01

131

Bacterial translocation and changes in the intestinal microbiome in mouse models of liver disease  

PubMed Central

Background & Aims Intestinal dysbiosis and bacterial translocation is common in patients with advanced liver disease, and there is strong evidence that the translocation of bacteria and their products across the epithelial barrier drives experimental liver disease progression. The aims of our study were to investigate dynamics of bacterial translocation and changes in the enteric microbiome in early stages of liver disease. Methods Cholestatic liver injury was induced by ligation of the common bile duct (BDL) and toxic liver injury by injection of carbon tetrachloride (CCl4) in mice. Results Increased intestinal permeability and bacterial translocation occurred one day following liver injury in both disease models. This was accompanied by decreased intestinal expression of the tight junction protein occludin. Although BDL resulted in a rapid onset of intestinal bacterial overgrowth, bacterial overgrowth was observed in mice injected with CCl4 only in advanced stages of liver fibrosis. To further assess the qualitative changes in the intestinal microbiome, massively parallel pyrosequencing of 16S rRNA genes revealed minor microbial changes following BDL, while CCl4 administration resulted in a relative abundance of Firmicutes and Actinobacteria compared with oil injected mice. Four different liver disease models (cholestasis, toxic, alcohol, obesity) show few similarities in their intestinal microbiome. Conclusions Acute liver injury is associated with an early onset of increased intestinal permeability and bacterial translocation that precede changes in the microbiome. The enteric microbiome differs with respect to the etiology of liver disease.

Fouts, Derrick E.; Torralba, Manolito; Nelson, Karen E.; Brenner, David A.; Schnabl, Bernd

2012-01-01

132

Acetaminophen: Background and Overview  

Center for Biologics Evaluation and Research (CBER)

Text Version1 Acetaminophen: Background and Overview Gerald J. Dal Pan, MD, MHS ... Page 86. 86 Background 1953 NDA 08-717 (acetaminophen tablet) ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

133

IR Background Suppression Studies.  

National Technical Information Service (NTIS)

A brief description of the background suppression scheme is described, and results obtained using the defocussing technique are presented. It has been demonstrated that a background suppression ratio of two orders of magnitudes can be obtained.

O. Shepherd W. P. Reidy T. F. Zehnpfennig G. A. Vanasse A. T. Stair

1977-01-01

134

Meiotic segregation analysis of a 14;21 Robertsonian translocation carrier by fluorescence in situ hybridization.  

PubMed

Meiotic segregation of chromosomes 14 and 21 in sperm from a 14;21 Robertsonian translocation carrier was analyzed with dual-color FISH using two locus-specific DNA probes (Tel 14q and LSI 21). The frequency of normal or chromosomally balanced sperm, resulting from alternate segregation, was 88.42%. The frequency of unbalanced sperm, resulting from adjacent segregation, was 11.25%. These observed frequencies deviated significantly from the theoretical frequencies (33.33% and 66.67%, respectively) based on random chromosome segregation, with sperm resulting from alternate segregation being preferentially produced in the translocation carrier. With respect to the chromosomally unbalanced sperm, the frequency of 21q disomic sperm was 2.45%, which is in agreement with the frequencies of unbalanced fetuses or offspring at the time of amniocentesis or at term (0-4.3%) reported by others. Although the frequency of 14 or 21 nullisomic sperm should be theoretically equal to that of 14q or 21q disomic sperm in both the carrier and controls, the frequency of nullisomic sperm was significantly higher than that of disomic sperm in the carrier (P=0.0009 for chromosome 14, P<0.0001 for chromosome 21) but not in the controls (P=0.091 for chromosome 14, P=0.74 for chromosome 21). This evidence suggests the occurrence of maturation arrest during spermatogenesis of the carrier. PMID:10746560

Honda, H; Miharu, N; Samura, O; He, H; Ohama, K

2000-02-01

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

Familial transmission of a translocation Y\\/14  

Microsoft Academic Search

A translocation of heterochromatic material, brightly fluorescent after actinomycin D-DAPI staining, to the short arm of chromosome 14 was prenatally detected during cytogenetic examination of cells obtained by amniocentesis on the indication of advanced maternal age. Besides this abnormal chromosome, 43 autosomes and two X chromosomes were present. Silver staining made clear that an active nucleolus-organizing region was included in

C. H. C. M. Buys; G. J. P. A. Anders; J. M. M. Borkent-Ypma; J. A. M. Blenkers-Platter; A. Y. Hoek-van der Veen

1979-01-01

137

Phylogenetic analyses of proton-translocating transhydrogenases.  

PubMed

The proton-translocating nicotinamide nucleotide transhydrogenases (TH) provide a simple model for understanding chemically coupled transmembrane proton translocation. To further our understanding of TH structure-function relationships, we have identified all sequenced homologous of these vectorial enzymes and have conducted sequence comparison studies. The NAD-binding domains of TH are homologous to bacterial alanine dehydrogenases (ADH) and eukaryotic saccharopine dehydrogenases (SDH) as well as N5(carboxyethyl)-L-ornithine synthase of Lactococcus lactis and dipicolinate synthase of Bacillus subtilis. A multiple alignment, a phylogenetic tree, and two signature sequences for this family, designated the TH-ADH-SDH or TAS superfamily, have been derived. Additionally, the TH family has been characterized. Phylogenetic analyses suggested that these proteins have evolved without inter-system shuffling. However, interdomain splicing-fusion events have occurred during the evolution of several of these systems. Analyses of the multiple alignment for the TH family revealed that domain conservation occurs in the order: NADP-binding domain (domain III) > NAD-binding domain (domain I) > proton-translocating transmembrane domain (domain II). A topologic model for the proton-translocating transmembrane domain consistent with published data is presented, and a possible involvement of specific transmembrane alpha-helical segments in channel formation is suggested. PMID:10587945

Studley, W K; Yamaguchi, M; Hatefi, Y; Saier, M H

1999-01-01

138

Polymer translocation out of planar confinements  

NASA Astrophysics Data System (ADS)

Polymer translocation in three dimensions out of planar confinements is studied in this paper. Three membranes are located at z = -h, z = 0 and z = h1. These membranes are impenetrable, except for the middle one at z = 0, which has a narrow pore. A polymer with length N is initially sandwiched between the membranes placed at z = -h and z = 0 and translocates through this pore. We consider strong confinement (small h), where the polymer is essentially reduced to a two-dimensional polymer, with a radius of gyration scaling as Rg(2D)~N?2D here, ?2D = 0.75 is the Flory exponent in two dimensions. The polymer performs Rouse dynamics. On the basis of theoretical analysis and high-precision simulation data, we show that in the unbiased case h = h1, the dwell time ?d scales as N2+?2D, in perfect agreement with our previously published theoretical framework. For h_1=\\infty , the situation is equivalent to field-driven translocation in two dimensions. We show that in this case ?d scales as N2?2D, in agreement with several existing numerical results in the literature. This result violates the earlier reported lower bound N1+? for ?d for field-driven translocation. We argue, on the basis of energy conservation, that the actual lower bound for ?d is N2? and not N1+?. Polymer translocation in such theoretically motivated geometries thus resolves some of the most fundamental issues that have been the subject of much heated debate in recent times.

Panja, Debabrata; Barkema, Gerard T.; Ball, Robin C.

2008-02-01

139

Jumping Translocations of 3q in Acute Promyelocytic Leukemia  

Microsoft Academic Search

Jumping translocation is a rare phenomenon, seldom reported to occur in cancer. A complex four-way translocation involving chromosomes 3, 9, 15, and 17 was identified in the chromosome study on a patient with a history of an acute promyelocytic leukemia (APL). In the follow-up studies, the same complex rearrangement exhibited a jumping translocation between chromosomes 3 and 9 in one

Jacqueline R Batanian; Cherie H Dunphy; Donna A Wall

1999-01-01

140

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

141

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

142

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

143

Chromosome translocations in T. scripta: the dose-rate effect and in vivo lymphocyte radiation response.  

PubMed

Using a whole-chromosome FISH painting probe we previously developed for chromosome 1 of the yellow-bellied slider turtle (Trachemys scripta), we investigated the dose-rate effect for radiation-induced symmetrical translocations in T. scripta fibroblasts and lymphocytes. The dose rate below which no reduction in effect per unit dose is observed with further dose protraction was approximately 23 cGy h(-1). We estimated the whole-genome spontaneous background level of complete, apparently simple symmetrical translocations in T. scripta lymphocytes to be approximately 1.20 x 10(-3)/cell projected from aberrations occurring in chromosome 1. Similar spontaneous background levels reported for humans are some 6- to 25-fold higher, ranging from about 6 x 10(-3) to 3.4 x 10(-2) per cell. This relatively low background level for turtles would be a significant advantage for resolution of effects at low doses and dose rates. We also chronically irradiated turtles over a range of doses from 0-8 Gy delivered at approximately 5.5 cGy h(-1) and constructed a lymphocyte dose-response curve for complete, apparently simple symmetrical translocations suitable for use with animals chronically exposed to radiation in contaminated environments. The best-fitting calibration curve (not constrained through the zero dose estimate) was of the form Y(as) = c + aD + bD(2), where Y(as) was the number of apparently simple symmetrical translocations per cell, D was the dose (Gy), a = (0.0058 +/- 0.0009), b = (-0.00033 +/- 0.00011), and c = (0.0015 +/- 0.0013). With additional whole-chromosome probes to improve sensitivity, environmental biodosimetry using stable chromosome translocations could provide a practical and genetically relevant measurement end point for ecological risk assessments and biomonitoring programs. PMID:11121217

Ulsh, B A; Whicker, F W; Congdon, J D; Bedford, J S; Hinton, T G

2001-01-01

144

Background stratospheric aerosol layer  

Microsoft Academic Search

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

D. J. Hofmann; J. M. Rosen

1981-01-01

145

GLAST Background Model.  

National Technical Information Service (NTIS)

In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles tha...

E. Grove F. Longo J. F. Ormes T. Burnett W. Atwood

2007-01-01

146

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

147

FISH analysis of translocations in lymphocytes of children exposed to the Chernobyl fallout: preferential involvement of chromosome 10  

Microsoft Academic Search

Using whole-chromosome painting probes, we have analyzed the frequency of translocations of chromosomes 1, 3, and 10 in peripheral lymphocytes of 20 Gomel (Belarus) children, including both thyroid tumor affected and healthy individuals. Gomel was one of the most heavily radiocontaminated areas due to fallout from the Chernobyl nuclear power plant disaster. As controls, 14 healthy children from Pisa (Italy)

R. Scarpato; A. Lori; G. Panasiuk; R. Barale

1997-01-01

148

Polymer translocation under time-dependent driving forces: Resonant activation induced by attractive polymer-pore interactions  

NASA Astrophysics Data System (ADS)

We study the driven translocation of polymers under time-dependent driving forces using N-particle Langevin dynamics simulations. We consider the force to be either sinusoidally oscillating in time or dichotomic noise with exponential correlation time, to mimic both plausible experimental setups and naturally occurring biological conditions. In addition, we consider both the case of purely repulsive polymer-pore interactions and the case with additional attractive polymer-pore interactions, typically occurring inside biological pores. We find that the nature of the interaction fundamentally affects the translocation dynamics. For the non-attractive pore, the translocation time crosses over to a fast translocation regime as the frequency of the driving force decreases. In the attractive pore case, because of a free energy well induced inside the pore, the translocation time can be a minimum at the optimal frequency of the force, the so-called resonant activation. In the latter case, we examine the effect of various physical parameters on the resonant activation, and explain our observations using simple theoretical arguments.

Ikonen, Timo; Shin, Jaeoh; Sung, Wokyung; Ala-Nissila, Tapio

2012-05-01

149

Translocation and encapsulation of siRNA inside carbon nanotubes  

NASA Astrophysics Data System (ADS)

We report spontaneous translocation of small interfering RNA (siRNA) inside carbon nanotubes (CNTs) of various diameters and chirality using all atom molecular dynamics simulations with explicit solvent. We use umbrella sampling method to calculate the free energy landscape of the siRNA entry and translocation event. Free energy profiles show that siRNA gains free energy while translocating inside CNT, and barrier for siRNA exit from CNT ranges from 40 to 110 kcal/mol depending on CNT chirality and salt concentration. The translocation time ? decreases with the increase of CNT diameter with a critical diameter of 24 A? for the translocation. In contrast, double strand DNA of the same sequence does not translocate inside CNT due to large free energy barrier for the translocation. This study helps in understanding the nucleic acid transport through nanopores at microscopic level and may help designing carbon nanotube based sensor for siRNA.

Mogurampelly, Santosh; Maiti, Prabal K.

2013-01-01

150

Models of post-translational protein translocation.  

PubMed Central

Organellar Hsp-70 is required for post-translational translocation into the endoplasmic reticulum and mitochondria. The functional role played by Hsp-70 is unknown. However, two operating principles have been suggested. The power stroke model proposes that Hsp-70 undergoes a conformational change, which pulls the precursor protein through the translocation pore, whereas, in the Brownian ratchet model, the role of Hsp-70 is simply to block backsliding through the pore. A mathematical analysis of both mechanisms is presented and reveals that qualitative differences between the models occur in the behavior of the mean velocity and effective diffusion coefficient as a function of Hsp-70 concentration. An experimental method is proposed for measuring these two quantities that only relies on current experimental techniques.

Elston, T C

2000-01-01

151

Mechanical Design of Translocating Motor Proteins  

Microsoft Academic Search

Translocating motors generate force and move along a biofilament track to achieve diverse functions including gene transcription,\\u000a translation, intracellular cargo transport, protein degradation, and muscle contraction. Advances in single molecule manipulation\\u000a experiments, structural biology, and computational analysis are making it possible to consider common mechanical design principles\\u000a of these diverse families of motors. Here, we propose a mechanical parts list

Wonmuk Hwang; Matthew J. Lang

2009-01-01

152

Chondrodysplasia punctata with X;Y translocation  

Microsoft Academic Search

We have studied a family in which the mother and her son were carriers of an X;Y translocation, der(X)t(X;Y) (p22.3;q11). The mother was of slightly short stature and had mildly short upper extremities. The son had epiphyseal punctate calcifications, mildly short extremities, a flattened nasal bridge, and mental retardation (chondrodysplasia punctata). The extra bands on the short arm of the

Kazunaga Agematsu; Kenichi Koike; Hironori Morosawa; Yutaka Nakahori; Yasuo Nakagome; Taro Akabane

1988-01-01

153

The GLAST Background Model  

SciTech Connect

In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

Ormes, J.F.; /Denver U.; Atwood, W.; /UC, Santa Cruz; Burnett, T.; /Washington U., Seattle; Grove, E.; /Naval Research Lab, Wash., D.C.; Longo, F.; /INFN, Pisa; McEnery, J.; /NASA, Goddard; Mizuno, T.; /Hiroshima U.; Ritz, S.; /NASA, Goddard

2007-10-17

154

The GLAST Background Model  

SciTech Connect

In order to estimate the ability of the GLAST/LAT to reject unwanted background of charged particles, optimize the on-board processing, size the required telemetry and optimize the GLAST orbit, we developed a detailed model of the background particles that would affect the LAT. In addition to the well-known components of the cosmic radiation, we included splash and reentrant components of protons, electrons (e+ and e-) from 10 MeV and beyond as well as the albedo gamma rays produced by cosmic ray interactions with the atmosphere. We made estimates of the irreducible background components produced by positrons and hadrons interacting in the multilayered micrometeorite shield and spacecraft surrounding the LAT and note that because the orbital debris has increased, the shielding required and hence the background are larger than were present in EGRET. Improvements to the model are currently being made to include the east-west effect.

Ormes, J. F. [University of Denver (United States); Atwood, W. [University of California at Santa Cruz (United States); Burnett, T. [University of Washington (United States); Grove, E. [Naval Research Laboratory (United States); Longo, F. [Instituto Nazionale di Fisica Nucleare (INFN)-Pisa (Italy); McEnery, J.; Ritz, S. [NASA Goddard Space Flight Center (United States); Mizuno, T. [Hiroshima University (Japan)

2007-07-12

155

Rapid Aquaporin Translocation Regulates Cellular Water Flow  

PubMed Central

The control of cellular water flow is mediated by the aquaporin (AQP) family of membrane proteins. The structural features of the family and the mechanism of selective water passage through the AQP pore are established, but there remains a gap in our knowledge of how water transport is regulated. Two broad possibilities exist. One is controlling the passage of water through the AQP pore, but this only has been observed as a phenomenon in some plant and microbial AQPs. An alternative is controlling the number of AQPs in the cell membrane. Here, we describe a novel pathway in mammalian cells whereby a hypotonic stimulus directly induces intracellular calcium elevations through transient receptor potential channels, which trigger AQP1 translocation. This translocation, which has a direct role in cell volume regulation, occurs within 30 s and is dependent on calmodulin activation and phosphorylation of AQP1 at two threonine residues by protein kinase C. This direct mechanism provides a rationale for the changes in water transport that are required in response to constantly changing local cellular water availability. Moreover, because calcium is a pluripotent and ubiquitous second messenger in biological systems, the discovery of its role in the regulation of AQP translocation has ramifications for diverse physiological and pathophysiological processes, as well as providing an explanation for the rapid regulation of water flow that is necessary for cell homeostasis.

Conner, Matthew T.; Conner, Alex C.; Bland, Charlotte E.; Taylor, Luke H. J.; Brown, James E. P.; Parri, H. Rheinallt; Bill, Roslyn M.

2012-01-01

156

Xp11 translocation renal cell carcinoma.  

PubMed

Xp11 translocation renal cell carcinoma (RCC) is a group of neoplasms characterised by translocations involving a breakpoint at Xp11.2. The resulting gene fusions involve the TFE3 transcription factor gene and multiple reported genes, including the same one (ASPL) found in the characteristic gene fusion of alveolar soft part sarcoma. Xp11 translocation RCCs likely comprise a significant proportion of paediatric RCCs. While uncommon on a percentage basis in adults, adult cases may outnumber paediatric cases due to the much higher overall incidence of RCC in the adult population. The only known risk factor for its development is prior exposure to chemotherapy. The most distinctive histological pattern is a neoplasm with both clear cells and papillary architecture, often with abundant psammoma bodies. Immunohistochemistry typically reveals minimal reactivity to cytokeratins, epithelial membrane antigen (EMA) or vimentin. The most sensitive and specific immunohistochemical markers for these neoplasms are TFE3 protein and cathepsin-K. Clinical outcome data are still premature at this time. However, children with regional nodal metastases but without haematogenous spread have a favourable short-term prognosis. Adults often present with aggressive tumours with widespread systemic metastases and these patients have a poor clinical outcome. Regardless, the tumour can metastasise decades after its initial presentation, so long-term follow-up is necessary. A recently reported melanotic neoplasm with overt melanin pigment may represent a new subset of TFE3 related cancers. PMID:20438411

Ross, Hillary; Argani, Pedram

2010-06-01

157

Translocation of Crohn's disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers  

PubMed Central

Background Crohn's disease is common in developed nations where the typical diet is low in fibre and high in processed food. Primary lesions overlie Peyer's patches and colonic lymphoid follicles where bacterial invasion through M-cells occurs. We have assessed the effect of soluble non-starch polysaccharide (NSP) and food emulsifiers on translocation of Escherichia coli across M-cells. Methods To assess effects of soluble plant fibres and food emulsifiers on translocation of mucosa-associated E coli isolates from Crohn's disease patients and from non-Crohn's controls, we used M-cell monolayers, generated by co-culture of Caco2-cl1 and Raji B cells, and human Peyer's patches mounted in Ussing chambers. Results E coli translocation increased across M-cells compared to parent Caco2-cl1 monocultures; 15.8-fold (IQR 6.2–32.0) for Crohn's disease E coli (N=8) and 6.7-fold (IQR 3.7–21.0) for control isolates (N=5). Electron microscopy confirmed E coli within M-cells. Plantain and broccoli NSP markedly reduced E coli translocation across M-cells at 5?mg/ml (range 45.3–82.6% inhibition, p<0.01); apple and leek NSP had no significant effect. Polysorbate-80, 0.01% vol/vol, increased E coli translocation through Caco2-cl1 monolayers 59-fold (p<0.05) and, at higher concentrations, increased translocation across M-cells. Similarly, E coli translocation across human Peyer's patches was reduced 45±7% by soluble plantain NSP (5?mg/ml) and increased 2-fold by polysorbate-80 (0.1% vol/vol). Conclusions Translocation of E coli across M-cells is reduced by soluble plant fibres, particularly plantain and broccoli, but increased by the emulsifier Polysorbate-80. These effects occur at relevant concentrations and may contribute to the impact of dietary factors on Crohn's disease pathogenesis.

Roberts, Carol L; Keita, Asa V; Duncan, Sylvia H; O'Kennedy, Niamh; Soderholm, Johan D; Rhodes, Jonathan M

2010-01-01

158

Translocation of Rac correlates with NADPH oxidase activation. Evidence for equimolar translocation of oxidase components.  

PubMed

Activation of the superoxide-generating NADPH oxidase system of human neutrophils involves the assembly of several neutrophil components, some located on the plasma membrane and others in the cytosol. It has recently been established that one of the required components for NADPH oxidase activity is the GTP-binding protein Rac. To further investigate the role of Rac in the NADPH oxidase system, studies were carried out to determine its subcellular distribution in resting and activated human neutrophils. In resting cells, Rac and an associated guanine nucleotide regulatory factor, GDP dissociation inhibitor (GDI), were located only in the cytosol, along with other known oxidase factors, p47-phox and p67-phox. After activation of neutrophils with phorbol 12-myristate 13-acetate or formyl-methionyl-leucyl-phenylalanine, Rac was translocated from the cytosol to the plasma membrane, and this translocation corresponded temporally with the translocation of p47-phox and p67-phox and with the generation of superoxide. GDI remained localized to the cytosol, suggesting activation of the oxidase involved dissociation of the Rac-GDI complex prior to Rac translocation. Determination of the quantities of cytosolic factors associated with the plasma membrane indicated that Rac, p47-phox, and p67-phox are translocated to the plasma membrane simultaneously in equimolar amounts, but that the membrane-associated cytochrome b was present at 3-4-fold molar excess. These findings suggest that Rac may play a role in assembly of the active NADPH oxidase complex. PMID:8407934

Quinn, M T; Evans, T; Loetterle, L R; Jesaitis, A J; Bokoch, G M

1993-10-01

159

Reciprocal translocations in somatic and germ cells of mice chronically exposed by inhalation to ethylene oxide: implications for risk assessment  

PubMed Central

Groups of male B6C3F1 mice were exposed by inhalation to 0, 25, 50, 100 or 200 p.p.m. ethylene oxide (EO) for up to 48 weeks (6 hours/day, 5 days/week). Animals were sacrificed at 6, 12, 24 and 48 weeks after the start of the exposure for analyses of reciprocal translocations in peripheral blood lymphocytes and germ cells. The frequency of the total chromosomal aberrations in the peripheral blood lymphocytes was significantly increased at the 100 and 200 p.p.m. exposure concentrations at the 12-week time point, at 50, 100 and 200 p.p.m. at the 24-week time point and at all EO concentrations at the 48-week time point. The frequency of stable reciprocal translocations, which can be used as biomarkers, was increased (P?translocation frequencies at the 6-week time point in the peripheral blood lymphocytes. The exposure–response curves were non-linear when the frequencies of translocations were plotted against EO exposure durations or against EO exposure concentrations. There was no effect of exposure concentration rate on reciprocal translocation frequency. Reciprocal translocations induced in spermatogonial stem cells (observed at the sprematocyte stage) showed significant increases in translocation frequencies over controls at all EO concentrations at 48 weeks. However, increases were small and they did not occur in a dose-responsive manner. The statistically significant increase observed at 12 weeks in the spermatocytes was equivocal. This study provides low-level chronic exposure somatic cytogenetic data generated in mice that can be used to support the shape of the tumour dose–response in rodents and humans The germ cell cytogenetic data are discussed in terms of its relevance for a threshold response for genetic effects at low exposures.

Donner, E. Maria; Wong, Brian A.; James, R. Arden; Preston, R. Julian

2010-01-01

160

Determination of RNA orientation during translocation through a biological nanopore.  

PubMed

We investigate single-molecule electrophoretic translocation of A(50), C(50), A(25)C(50), and C(50)A(25) RNA molecules through the alpha-hemolysin transmembrane protein pore. We observe pronounced bilevel current blockages during translocation of A(25)C(50) and C(50)A(25) molecules. The two current levels observed during these bilevel blockages are very similar to the characteristic current levels observed during A(50) and C(50) translocation. From the temporal ordering of the two levels within the bilevel current blockages, we infer whether individual A(25)C(50) and C(50)A(25) molecules pass through the pore in a 3'-->5' or 5'-->3' orientation. Correlation between the level of current obstruction and the inferred A(25)C(50) or C(50)A(25) orientation indicates that 3'-->5' translocation of a poly C segment causes a significantly deeper current obstruction than 5'-->3' translocation. Our analysis also suggests that the 3' ends of C(50) and A(25)C(50) RNA molecules are more likely to initiate translocation than the 5' ends. Orientation dependent differences in a smaller current blockage that immediately precedes many translocation events suggest that this blockage also contains information about RNA orientation during translocation. These findings emphasize that the directionality of polynucleotide molecules is an important factor in translocation and demonstrate how structure within ionic current signals can give new insights into the translocation process. PMID:16214857

Butler, Tom Z; Gundlach, Jens H; Troll, Mark A

2005-10-07

161

Translocation of surface-localized effectors in type III secretion.  

PubMed

Pathogenic Yersinia species suppress the host immune response by using a plasmid-encoded type III secretion system (T3SS) to translocate virulence proteins into the cytosol of the target cells. T3SS-dependent protein translocation is believed to occur in one step from the bacterial cytosol to the target-cell cytoplasm through a conduit created by the T3SS upon target cell contact. Here, we report that T3SS substrates on the surface of Yersinia pseudotuberculosis are translocated into target cells. Upon host cell contact, purified YopH coated on Y. pseudotuberculosis was specifically and rapidly translocated across the target-cell membrane, which led to a physiological response in the infected cell. In addition, translocation of externally added YopH required a functional T3SS and a specific translocation domain in the effector protein. Efficient, T3SS-dependent translocation of purified YopH added in vitro was also observed when using coated Salmonella typhimurium strains, which implies that T3SS-mediated translocation of extracellular effector proteins is conserved among T3SS-dependent pathogens. Our results demonstrate that polarized T3SS-dependent translocation of proteins can be achieved through an intermediate extracellular step that can be reconstituted in vitro. These results indicate that translocation can occur by a different mechanism from the assumed single-step conduit model. PMID:21220342

Akopyan, Karen; Edgren, Tomas; Wang-Edgren, Helen; Rosqvist, Roland; Fahlgren, Anna; Wolf-Watz, Hans; Fallman, Maria

2011-01-10

162

Differences in uptake and translocation of selenate and selenite by the weeping willow and hybrid willow  

Microsoft Academic Search

Background, aim, and scope  Due to its essentiality, deficiency, and toxicity to living organisms and the extensive use in industrial activities, selenium\\u000a (Se) has become an element of global environmental and health concern. Se removal from contaminated sites using physical,\\u000a chemical, and engineering techniques is quite complicated and expensive. The goal of this study was to investigate uptake\\u000a and translocation of

Xiao-Zhang Yu; Ji-Dong Gu

2008-01-01

163

Expression pattern of a nuclear encoded mitochondrial arginine-ornithine translocator gene from Arabidopsis  

Microsoft Academic Search

BACKGROUND: Arginine and citrulline serve as nitrogen storage forms, but are also involved in biosynthetic and catabolic pathways. Metabolism of arginine, citrulline and ornithine is distributed between mitochondria and cytosol. For the shuttle of intermediates between cytosol and mitochondria transporters present on the inner mitochondrial membrane are required. Yeast contains a mitochondrial translocator for ornithine and arginine, Ort1p\\/Arg11p. Ort1p\\/Arg11p is

Elisabetta Catoni; Marcelo Desimone; Melanie Hilpert; Daniel Wipf; Reinhard Kunze; Anja Schneider; U. I. Flugge; Karin Schumacher; Wolf B Frommer

2003-01-01

164

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

165

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

166

Matching Background Color  

NSDL National Science Digital Library

This chapter introduces an especially important subject in the concealment of animals--countershading. One observes many animals with colors that match the general color of their usual backgrounds. Many leaf-eating insects appear green, for example, making them relatively inconspicuous against their normal background of leaves. The manner of coloration that will provide such a color match is not as obvious as one might imagine. It depends significantly on the nature of the lighting. The inquiry-based activities included in this section effectively illustrate this concept.

Ipsen, David; Gillfillan, Gretchen L.; Judy Diamond (Revised New Edition); Judy Scotchmoor (Revised New Edition); Stebbins, Robert

2008-04-01

167

China: Background Notes Series.  

ERIC Educational Resources Information Center

Concise background information on the People's Republic of China is provided. The publication begins with a profile of the country, outlining the people, geography, economy, and membership in international organizations. The bulk of the document then discusses in more detail China's people, geography, history, government, education, economy, and…

Reams, Joanne Reppert

168

Foregrounding the Background.  

ERIC Educational Resources Information Center

Argues that when introductory activities to the classics begin with background information, it can upstage or confine the life of the story, and shows little faith in the students as readers or in the literature itself. Suggests sometimes letting the literature begin, and then helping students make sense of it. Discusses examples from "To Kill a…

Robbins, Bruce

1998-01-01

169

Building Background Knowledge  

ERIC Educational Resources Information Center

|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 their ability to ask questions and wonder--both key components of inquiry. In this article,…

Fisher, Douglas; Ross, Donna; Grant, Maria

2010-01-01

170

Taiwan: Background Notes Series.  

ERIC Educational Resources Information Center

|Concise background information on Taiwan is provided. The publication begins with a profile of Taiwan, discussing the people, geography, political establishment, and economy. A map of the country is provided. The bulk of the publication then provides more detailed information on Taiwan's people, geography, history, administration, political…

Reams, Joanne Reppert

171

Background Level Care  

Microsoft Academic Search

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

N. B. Pitts

2009-01-01

172

Cosmic background radiation  

Microsoft Academic Search

We summarise the current status of cosmic microwave background spectrum and\\u000aanisotropy measurements, and their theoretical interpretation. This is the\\u000aupdate of the mini-review for the 1997 web-version of the Review of Particle\\u000aProperties.

George Smoot; Douglas Scott

2000-01-01

173

Diffuse UV Background  

NASA Astrophysics Data System (ADS)

We propose a LEGACY project, with the aim of characterizing the diffuse ultraviolet background radiation. In order to achieve maximum impact, we propose to observe exclusively targets for which we already have in hand Voyager diffuse - background spectra (shortward of Lyman alpha). Our Voyager spectroscopy will allow powerful insight into the interpretation and meaning of the deep GALEX images longward of Lyman alpha that we propose (here) to obtain. There is good evidence that a substantial portion of the diffuse UV background at moderate and high Galactic latitudes is exotic in its origin - that is, that the radiation is not simply diffuse galactic light plus the integrated light of distant galaxies. We propose to find clues to the nature and physical origin of the diffuse ultraviolet background radiation in as comprehensive a manner as can be accomplished using GALEX. But in the course of carrying out the proposed work, we will also be creating a permanent GALEX archive of well-chosen deep images that are supported by spectroscopy - images valuable for a wide range of purposes beyond those that we propose. To speed this broader use, we waive all data rights.

Henry, Richard

174

Effects of Genomic Length on Translocation of Hepatitis B Virus Polymerase-Linked Oligomer  

PubMed Central

Accurate translocation of the polymerase-linked oligomer to the acceptor site (DR1*) in reverse transcription is crucial for maintaining the correct size of the hepatitis B virus (HBV) genome. Various sizes of foreign sequences were inserted at different sites of the HBV genome, and their effects on accurate translocation of polymerase-linked oligomer to DR1* were tested. Three types of replicate DNA products were observed in these insertion mutants: RC (relaxed circle) and type I and type II DL (duplex linear) DNA. Our results indicated that the minus strand of RC and type I DL form was elongated from DR1*, while the minus strand of the type II DL form was elongated from multiple internal acceptor sites (IAS), such as IAS2. These IASs were also found to be used by wild-type HBV but with a very low frequency. Mutation of IAS2 by base substitution abrogated polymerase-linked oligomer transferring to IAS2, demonstrating that base pairing also plays an important role in the function of IAS2 as a polymerase-linked oligomer acceptor site. Data obtained from our insertion mutants also demonstrate that the distance between the polymerase-linked oligomer priming site and the acceptor is important. The polymerase-linked oligomer prefers to translocate to an acceptor, DR1* or IAS2, which are ca. 3.2 kb apart. However, it will translocate to both DR1* and IAS2 if they are not located 3.2 kb apart. These results suggest that the polymerase-linked oligomer may be able to scan bidirectionally for appropriate acceptor sites at a distance of 3.2 kb. A model is proposed to discuss the possible mechanism of polymerase-linked oligomer translocation.

Ho, Tsung-Chuan; Jeng, King-Song; Hu, Cheng-Po; Chang, Chungming

2000-01-01

175

Effects of genomic length on translocation of hepatitis B virus polymerase-linked oligomer.  

PubMed

Accurate translocation of the polymerase-linked oligomer to the acceptor site (DR1*) in reverse transcription is crucial for maintaining the correct size of the hepatitis B virus (HBV) genome. Various sizes of foreign sequences were inserted at different sites of the HBV genome, and their effects on accurate translocation of polymerase-linked oligomer to DR1* were tested. Three types of replicate DNA products were observed in these insertion mutants: RC (relaxed circle) and type I and type II DL (duplex linear) DNA. Our results indicated that the minus strand of RC and type I DL form was elongated from DR1*, while the minus strand of the type II DL form was elongated from multiple internal acceptor sites (IAS), such as IAS2. These IASs were also found to be used by wild-type HBV but with a very low frequency. Mutation of IAS2 by base substitution abrogated polymerase-linked oligomer transferring to IAS2, demonstrating that base pairing also plays an important role in the function of IAS2 as a polymerase-linked oligomer acceptor site. Data obtained from our insertion mutants also demonstrate that the distance between the polymerase-linked oligomer priming site and the acceptor is important. The polymerase-linked oligomer prefers to translocate to an acceptor, DR1* or IAS2, which are ca. 3.2 kb apart. However, it will translocate to both DR1* and IAS2 if they are not located 3.2 kb apart. These results suggest that the polymerase-linked oligomer may be able to scan bidirectionally for appropriate acceptor sites at a distance of 3.2 kb. A model is proposed to discuss the possible mechanism of polymerase-linked oligomer translocation. PMID:10982345

Ho, T C; Jeng, K S; Hu, C P; Chang, C

2000-10-01

176

Genomic Hallmarks of Genes Involved in Chromosomal Translocations in Hematological Cancer  

PubMed Central

Reciprocal chromosomal translocations (RCTs) leading to the formation of fusion genes are important drivers of hematological cancers. Although the general requirements for breakage and fusion are fairly well understood, quantitative support for a general mechanism of RCT formation is still lacking. The aim of this paper is to analyze available high-throughput datasets with computational and robust statistical methods, in order to identify genomic hallmarks of translocation partner genes (TPGs). Our results show that fusion genes are generally overexpressed due to increased promoter activity of 5? TPGs and to more stable 3?-UTR regions of 3? TPGs. Furthermore, expression profiling of 5? TPGs and of interaction partners of 3? TPGs indicates that these features can help to explain tissue specificity of hematological translocations. Analysis of protein domains retained in fusion proteins shows that the co-occurrence of specific domain combinations is non-random and that distinct functional classes of fusion proteins tend to be associated with different components of the gene fusion network. This indicates that the configuration of fusion proteins plays an important role in determining which 5? and 3? TPGs will combine in specific fusion genes. It is generally accepted that chromosomal proximity in the nucleus can explain the specific pairing of 5? and 3? TPGS and the recurrence of hematological translocations. Using recently available data for chromosomal contact probabilities (Hi-C) we show that TPGs are preferentially located in early replicated regions and occupy distinct clusters in the nucleus. However, our data suggest that, in general, nuclear position of TPGs in hematological cancers explains neither TPG pairing nor clinical frequency. Taken together, our results support a model in which genomic features related to regulation of expression and replication timing determine the set of candidate genes more likely to be translocated in hematological tissues, with functional constraints being responsible for specific gene combinations.

Shugay, Mikhail; Ortiz de Mendibil, Inigo; Vizmanos, Jose L.; Novo, Francisco J.

2012-01-01

177

Refinement of background environmental monitoring measurements using meteorological frequency distribution  

SciTech Connect

Since the Radiological Environmental Monitoring Program's inception in 1969, the direct radiation monitoring network around the Oyster Creek nuclear generating station has incorporated both monthly and quarterly thermoluminescent dosimetry (TLD). In 1988, the environmental controls department of GPU Nuclear decided to eliminate the monthly TLD network for scientific and economic reasons. The most obvious scientific basis on which to designate TLD stations is by meteorology. It would be the plume path that dictates off-site direct radiation contribution from the plant and not simply distance from the site. Through meteorological and statistical analysis of existing TLD results, the appropriate basis for designating TLD stations has been accomplished that will provide the most accurate and comprehensive data on environmental measurement of releases from Oyster Creek.

Schwartz, P.E. (GPU Nuclear Corp., Forked River, NJ (United States))

1991-01-01

178

Commensal microflora induce host defense and decrease bacterial translocation in burn mice through toll-like receptor 4  

Microsoft Academic Search

BACKGROUND: Major burn is associated with decreased gut barrier function and increased bacterial translocation (BT). This study is to investigate whether commensal microflora induce host defense and decrease BT in burn mice. METHODS: First, we treated Wild type (WT) mice with antibiotics in drinking water for 4 weeks to deplete gut commensal microflora. At week 3, drinking water was supplemented

Lee-Wei Chen; Wei-Jung Chang; Pei-Hsuan Chen; Ching-Mei Hsu

2010-01-01

179

The invariant phenylalanine of precursor proteins discloses the importance of Omp85 for protein translocation into cyanelles  

Microsoft Academic Search

BACKGROUND: Today it is widely accepted that plastids are of cyanobacterial origin. During their evolutionary integration into the metabolic and regulatory networks of the host cell the engulfed cyanobacteria lost their independency. This process was paralleled by a massive gene transfer from symbiont to the host nucleus challenging the development of a retrograde protein translocation system to ensure plastid functionality.

Tobias Wunder; Roman Martin; Wolfgang Löffelhardt; Enrico Schleiff; Jürgen M Steiner

2007-01-01

180

Increased membrane-associated protein kinase C activity and translocation in blood platelets from bipolar affective disorder patients  

Microsoft Academic Search

Background: recent investigations have suggested that the phosphoinositide (PI) signal transduction system may be involved in the pathophysiology of bipolar affective disorders. Earlier studies in our laboratory have implicated altered PKC-mediated phosphorylation in bipolar affective disorder and in the clinical action of lithium. In the present study, we compared PKC activity and its translocation in platelets from subjects with bipolar

Hoau-Yan Wang; Philip Markowitz; Douglas Levinson; Ashiwel S Undie; Eitan Friedman

1999-01-01

181

Hypomethylation and expression of BEX2, IGSF4 and TIMP3 indicative of MLL translocations in Acute Myeloid Leukemia  

Microsoft Academic Search

BACKGROUND: Translocations of the Mixed Lineage Leukemia (MLL) gene occur in a subset (5%) of acute myeloid leukemias (AML), and in mixed phenotype acute leukemias in infancy - a disease with extremely poor prognosis. Animal model systems show that MLL gain of function mutations may contribute to leukemogenesis. Wild-type (wt) MLL possesses histone methyltransferase activity and functions at the level

Sonja Röhrs; Wilhelm G Dirks; Claus Meyer; Rolf Marschalek; Michaela Scherr; Robert Slany; Andrew Wallace; Hans G Drexler; Hilmar Quentmeier

2009-01-01

182

Anomalous zipping dynamics and forced polymer translocation  

NASA Astrophysics Data System (ADS)

We investigate by means of Monte Carlo simulations the zipping and unzipping dynamics of two polymers connected at one end and subject to an attractive interaction between complementary monomers. In zipping, the polymers are quenched from a high temperature equilibrium configuration to a low temperature state, such that the two strands zip up by closing up a 'Y'-fork. In unzipping, the polymers are brought from a low temperature double-stranded configuration to high temperatures, such that the two strands separate. Simulations show that the unzipping time, ?u, scales as a function of the polymer length as ?u ~ L, while the zipping is characterized by the anomalous dynamics ?z ~ L? with ? = 1.37(2). This exponent is in good agreement with simulation results and theoretical predictions for the scaling of the translocation time of a forced polymer passing through a narrow pore. We find that the exponent ? is robust against variations of parameters and temperature, whereas the scaling of ?z as a function of the driving force shows the existence of two different regimes: the weak forcing (?z ~ 1/F) and strong forcing (?z independent of F) regimes. The crossover region is possibly characterized by a non-trivial scaling in F, matching the prediction of recent theories of polymer translocation. Although the geometrical setups are different, zipping and translocation share thus the same type of anomalous dynamics. Systems where this dynamics could be experimentally investigated include DNA (or RNA) hairpins: our results imply an anomalous dynamics for the hairpins' closing times, but not for the opening times.

Ferrantini, A.; Carlon, E.

2011-02-01

183

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

2013-08-30

184

Saccharomyces cerevisiae ATM orthologue suppresses break-induced chromosome translocations  

Microsoft Academic Search

Chromosome translocations are frequently associated with many types of blood-related cancers and childhood sarcomas. Detection of chromosome translocations assists in diagnosis, treatment and prognosis of these diseases; however, despite their importance to such diseases, the molecular mechanisms leading to chromosome translocations are not well understood. The available evidence indicates a role for non-homologous end joining (NHEJ) of DNA double-strand breaks

Kihoon Lee; Yu Zhang; Sang Eun Lee

2008-01-01

185

Target detection against narrow band noise backgrounds.  

PubMed

We studied the detectability of narrow band random noise targets embedded in narrow band random noise backgrounds as a function of differences in center frequency, spatial frequency bandwidth and orientation bandwidth between target and the immediately adjacent background. Unlike most target detection experiments the targets were not added to the background; they replaced the underlying background texture. Simulations showed that target detection probabilities could be accounted for by a simple transformation on the summed outputs of a two layer filter model similar to the complex channels model proposed by Graham, Beck and Sutter (Graham, N., Beck, J., & Sutter, A. (1992). Vision Research, 32, 719-743). Subsequently, the model was tested on the detection of camouflaged vehicle targets with encouraging results. PMID:10343801

Cannon, M W; Reese, G J; Fullenkamp, S C

1999-06-01

186

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

187

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

188

Mandibular Ewing sarcoma with chromosomal translocation t(21;22)(q22;q12).  

PubMed

Ewing sarcoma (ES) is a primary bone malignant neoplasm and is the second most common primary malignancy of the bone found in childhood and adolescence after osteosarcoma. ES has an annual frequency in the population younger than 20 years of approximately 2.9 per million. ES occurs most frequently in the long bones of the extremities and pelvis and very rarely in the jaw. Recently, it was revealed that chromosomal translocation t(11;22)(q24;q12), which fuses the EWS gene on chromosome 22 and the FLI-1 gene on chromosome 11, occurs in most cases of ES. We report here a rare case of mandibular ES in a 10-year-old child with chromosomal translocation t(21;22)(q22;q12) in which the EWS gene is fused with the ERG gene on chromosome 21. PMID:23851834

Shibasaki, Maiko; Iwai, Toshinori; Maegawa, Jiro; Inayama, Yoshiaki; Yokosuka, Tomoko; Yokota, Shumpei; Ohta, Shinsuke; Matsui, Yoshiro; Mitsudo, Kenji; Tohnai, Iwai

2013-07-01

189

A prevalent Y;15 translocation in the Ethiopian Beta Israel community in Israel.  

PubMed

We describe 7 cases of abnormal karyotypes involving chromosomes Y and 15 in Ethiopian Beta Israel patients: 46,XX, der(15)t(Y;15)(q12;p12) and 46,XY,der(15)t(Y;15)(q12;p12). Six cases were incidentally found in amniocentesis performed for various indications; the indication for karyotyping in 1 case was recurrent abortions. To the best of our knowledge, this is the first report of this translocation in a specific ethnic group. We conclude that the derivative chromosome 15 with chromosome Y is probably a normal variant in Ethiopian Beta Israel occurring at an estimated frequency of 4/74 (5.4%). The prenatal diagnosis of this translocation in this population probably does not require further parental testing. PMID:22327880

Chen-Shtoyerman, R; Josefsberg Ben-Yehoshua, S; Nissani, R; Rosensaft, J; Appelman, Z

2012-02-11

190

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

191

Racial differences in the incidence of mesenchymal tumors associated with EWSR1 translocation  

PubMed Central

Background The incidence of Ewing sarcoma varies by race, with very low rates among persons of African and East Asian ancestry. The incidence by race of other mesenchymal tumors that also harbor EWSR1 translocations has not been studied. Methods The SEER database was queried to find cases of mesenchymal tumors associated with EWSR1 translocations: Ewing sarcoma; clear cell sarcoma; extraskeletal myxoid chondrosarcoma; myxoid liposarcoma; desmoplastic small round cell tumor and myoepithelial tumor. Age-adjusted incidence rates were calculated for white, African-American, and Asian/Native American populations and compared statistically. Results Ewing sarcoma was significantly less common in the African-American and Asian/Native American populations compared to the white population, with incidence rate ratios of 0.12 (95% confidence interval 0.08 – 0.20; p < 0.001) and 0.54 (95% confidence interval 0.41 – 0.69; p < 0.001), respectively. Desmoplastic small round cell tumor was significantly more common in the African-American population compared to the white population (incidence rate ratio 3.0; 95% confidence interval 1.62 – 5.49; p < 0.001). Myxoid liposarcoma was significantly less common in the Asian/Native American population compared to the white population (incidence rate ratio 0.72; 95% confidence interval 0.56 – 0.92; p-value 0.006). The incidence rates for extraskeletal myxoid chondrosarcoma, myoepithelial tumors, and clear cell sarcoma did not differ significantly by race. Conclusions Tumors associated with EWSR1 translocation are not uniformly more common in people of European ancestry. Impact The relationship between race and EWSR1 somatic translocation is complex. Future studies investigating the genetic epidemiology of EWSR1 translocated tumors are required.

Worch, Jennifer; Cyrus, Jobin; Goldsby, Robert; Matthay, Katherine K.; Neuhaus, John; DuBois, Steven G.

2011-01-01

192

Secretory immunoglobulin A, intestinal mucin, and mucosal permeability in nutritionally induced bacterial translocation in rats.  

PubMed Central

OBJECTIVE. The authors investigated the role of mucin and secretory immunoglobulin A (slgA) in a model of nutritionally induced bacterial translocation. BACKGROUND. Parenteral and certain elemental diets have been shown to impair intestinal barrier function, whereas fiber has been shown to protect against nutritionally induced bacterial translocation. However, the factors responsible for these phenomenon have not been fully determined. METHODS. Intestinal mucin levels, mucosal protein content, slgA, intestinal morphology, and permeability to horseradish peroxidase, bacterial translocation, and intestinal bacterial population levels were measured in rats 7 days after receiving total parenteral nutrition (TPN) solution (28% glucose, 4.25% amino acids; 307 kcal/kg/day) enterally (ORAL-TPN) or parenterally (IV-TPN) with or without enteral bulk fiber supplementation. Chow-fed rats served as control subjects. RESULTS. The incidence of bacterial translocation in the ORAL-TPN and IV-TPN groups was reduced significantly by the provision of fiber (p < 0.05). Mucosal protein, slgA, and insoluble mucin levels were decreased in the jejunum of the ORAL-TPN and IV-TPN groups, with mucosal protein levels being decreased to a greater extent than slgA or mucin. Although similar decreases in these parameters were observed in the fiber-fed groups, fiber appeared to improve intestinal barrier function as measured by horseradish peroxidase permeability. CONCLUSIONS. The provision of bulk-forming fiber improves intestinal barrier function as measured by peroxidase permeability and bacterial translocation, but does not restore mucosal protein content, intestinal mucin, or slgA levels to normal. Images Figure 2. Figure 3. Figure 4. Figure 5.

Spaeth, G; Gottwald, T; Specian, R D; Mainous, M R; Berg, R D; Deitch, E A

1994-01-01

193

The clinical significance of the FUS-CREB3L2 translocation in low-grade fibromyxoid sarcoma  

Microsoft Academic Search

Background  Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue neoplasm with a deceptively benign histological appearance. Local\\u000a recurrences and metastases can manifest many years following excision. The FUS-CREB3L2 gene translocation, which occurs commonly in LGFMS, may be detected by reverse-transcriptase polymerase chain reaction (RT-PCR)\\u000a and fluorescence in situ hybridisation (FISH). We assessed the relationship between clinical outcome and translocation test\\u000a result

Barry Rose; George S Tamvakopoulos; Kamaljit Dulay; Robin Pollock; John Skinner; Timothy Briggs; Steven Cannon

2011-01-01

194

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

195

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

196

[Transplantation of the intestines and bacterial translocation].  

PubMed

Infections, sepsis and multiple organ failure syndrome are associated with high morbidity and mortality in human and experimental small bowel transplantation (SBTx). These complications are attributed to bacterial translocation demonstrated in animal and human studies. Bacterial translocation (BT) is defined as the passage of viable bacteria from the intestinal lumen to other tissues or organs. BT has been associated with different clinical and experimental situations, hemorrhagic shock, trauma, bowel obstruction, immunodepression, total parenteral nutrition, antibiotics. Although BT has been investigated in several small and large animal models of SBTx, precise information on the mechanisms involved are not available. It is possible that the operative procedure by itself may promote BT for the interaction of a number of factors such as preservation, ischemia/reperfusion, abnormal motility, lymphatic disruption and aberrant systemic venous drainage, acute or chronic rejection and antibiotic therapy. Furthermore, the potent immunosuppressive therapy used in these patients may augment the deleterious effects caused by BT. In this review we examined the existing literature concerning BT with particular regard to intestinal transplantation, to better understand the alterations in the symbiotic relationship between immunocompromised host and his gut microflora after SBTx. PMID:10812777

Sileri, P; Rastellini, C; Dicuonzo, G; Gaspari, A; Benedetti, E; Cicalese, L

2000-04-01

197

Microbial Translocation in Chronic Liver Diseases  

PubMed Central

The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products (i.e., LPS, lipopeptides) from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. The most recent evidence suggests that microbial translocation (MT) may occur not only in cirrhosis, but also in the early stage of several liver diseases, including alcoholic hepatopathy and nonalcoholic fatty liver disease. Different mechanisms, such as small intestinal bacterial overgrowth, increased permeability of intestinal mucosa, and impaired immunity, may favor MT. Furthermore, MT has been implicated in the pathogenesis of the complications of cirrhosis, which are a significant cause of morbidity and mortality in cirrhotic subjects. Therapeutic strategies aiming at modulating the gut microflora and reducing MT have focused on antibiotic-based options, such as selective intestinal decontamination, and nonantibiotic-based options, such as prokinetics and probiotics. In particular, probiotics may represent an attractive strategy, even though the promising results of experimental models and limited clinical studies need to be confirmed in larger randomized trials.

Pinzone, Marilia Rita; Celesia, Benedetto Maurizio; Di Rosa, Michele; Cacopardo, Bruno; Nunnari, Giuseppe

2012-01-01

198

Evaluation of translocation criteria: case study with trumpeter swans ( Cygnus buccinator)  

Microsoft Academic Search

Translocations are a common conservation technique; however, the feasibility and success of translocations are evaluated rarely. We translocated 57 trumpeter swans (Cygnus buccinator) from Idaho to Utah during 1996 to encourage migration to more southern wintering areas. We evaluated the feasibility and success of the translocation by studying biological and socio-political criteria prior to and during the translocation. Lack of

Katharina A. M Engelhardt; John A Kadlec; Victoria L Roy; James A Powell

2000-01-01

199

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

200

Comparison of male and female meiotic segregation patterns in translocation heterozygotes: a case study in an animal model (Sus scrofa domestica L.)  

Microsoft Academic Search

BACKGROUND: The comparison of male and female meiotic segregation patterns for individuals carrying identi- cal reciprocal translocations has been rarely reported in mammalian species. The main comparative study invol- ving males and females with comparable genetic background has been performed in the mouse. Swine is another relevant animal model species for meiotic studies. Here we present the segregation patterns determined

A. Pinton; T. Faraut; M. Yerle; J. Gruand; F. Pellestor; A. Ducos

2005-01-01

201

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

202

A novel background model for real-time vehicle detection  

Microsoft Academic Search

A real-time background model initiation and maintenance algorithm for video surveillance is proposed. In order to detect foreground objects, firstly, the initial background scene is statically learned using the frequency of the pixel intensity values during training period. The frequency ratios of the intensity values for each pixel at the same position in the frames are calculated; the intensity values

Baisheng Clien; Yunqi Lei; Wangwei Li

2004-01-01

203

Frequency curves  

USGS Publications Warehouse

This manual describes graphical and mathematical procedures for preparing frequency curves from samples of hydrologic data. It also discusses the theory of frequency curves, compares advantages of graphical and mathematical fitting, suggests methods of describing graphically defined frequency curves analytically, and emphasizes the correct interpretations of a frequency curve.

Riggs, H. C.

1968-01-01

204

Cosmic microwave background polarization  

NASA Astrophysics Data System (ADS)

Cosmic microwave background (CMB) anisotropy is our richest source of cosmological information; the standard cosmological model was largely established thanks to study of the temperature anisotropies. By the end of the decade, the Planck satellite will close this important chapter and move us deeper into the new frontier of polarization measurements. Numerous ground-based and balloon-borne experiments are already forging into this new territory. Besides providing new and independent information on the primordial density perturbations and cosmological parameters, polarization measurements offer the potential to detect primordial gravity waves, constrain dark energy and measure the neutrino mass scale. A vigorous experimental program is underway worldwide and heading towards a new satellite mission dedicated to CMB polarization.

Bartlett, James G.

2006-05-01

205

Microbial translocation in the pathogenesis of HIV infection and AIDS.  

PubMed

In pathogenic simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) infections, the translocation of microbial products from the gastrointestinal (GI) tract to portal and systemic circulation has been proposed as a major driver of the chronic immune activation that is associated with disease progression. Consistently, microbial translocation is not present in nonpathogenic SIV infections of natural host species. In vivo studies demonstrated that HIV/SIV-associated microbial translocation results from a series of immunopathological events occurring at the GI mucosa: (i) early and severe mucosal CD4(+) depletion, (ii) mucosal immune hyperactivation/persistent inflammation; (iii) damage to the integrity of the intestinal epithelium with enterocyte apoptosis and tight junction disruption; and (iv) subverted the gut microbiome, with a predominance of opportunistic bacteria. Direct in situ evidence of microbial translocation has been provided for SIV-infected rhesus macaques showing translocated microbial products in the intestinal lamina propria and distant sites. While the mechanisms by which microbial translocation causes immune activation remain controversial, a key pathogenic event appears to be innate immunity activation via Toll-like receptors and other pathogen recognition receptors. Accumulating clinical observations suggest that microbial translocation might affect HIV disease progression, response to therapy, and non-AIDS comorbidities. Given its detrimental effect on overall immunity, several interventions to prevent/block microbial translocation are currently under investigation as novel therapeutic agents for HIV/AIDS. PMID:23297256

Marchetti, Giulia; Tincati, Camilla; Silvestri, Guido

2013-01-01

206

Dominant-lethal mutation and heritable translocation tests in mice  

Microsoft Academic Search

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. Chromosome breakage can result in chromosome loss, which often leads to embryonic lethality and occassionally to viable aneuploids, or to viable reciprocal translocations and inversions. In mice, transmitted chromosome breakage

Generoso

1980-01-01

207

Host species-specific translocation of Escherichia coli.  

PubMed

The purpose of this paper is to investigate the rate of translocation of Escherichia coli strains in different experimental/animal models. Four proficient translocating E. coli strains isolated from mesenteric lymph nodes (MLNs) and/or the blood of rats (strains KIC-1 and KIC-2), from a fatal case of pancreatitis (HMLN-1) and from pigs (PC-1 isolated in this study) were tested for their ability to translocate across two host species and the Caco-2 cell line as a model of the human gut epithelium. HMLN-1 was found in the MLNs of all 15 pigs tested. This strain, however, did not translocate in any rats and only colonised the caecum of four rats in small numbers. HMLN-1 and PC-1 were the dominant translocating strains in Caco-2 cells compared to KIC-1 and KIC-2, which were found to translocate at a lower rate in pigs and in Caco-2 cells. The rate of translocation of PC-1 in rats was also very low compared to KIC-1 and KIC-2. We suggest that, in studies aiming to investigate the mechanism of translocation of E. coli strains isolated from humans, rats may not be an appropriate animal model and that the Caco-2 cells or pigs are more suitable in vitro and in vivo models, respectively. PMID:19437050

Katouli, M; Ramos, N L; Nettelbladt, C G; Ljungdahl, M; Robinson, W; Ison, H M; Brauner, A; Möllby, R

2009-05-13

208

DNA double-strand break repair and chromosome translocations  

Microsoft Academic Search

Translocations are genetic aberrations that occur when a broken fragment of a chromosome is erroneously rejoined to another chromosome. The initial event in the creation of a translocation is the formation of a DNA double-strand break (DSB), which can be induced both under physiological situations, such as during the development of the immune system, or by exogenous DNA damaging agents.

Sheba Agarwal; Agnieszka A. Tafel; Roland Kanaar

2006-01-01

209

Sulfur dioxide inhibition of translocation in bean plants  

Microsoft Academic Search

Exposure of the source leaf of bean (Phaseolus vulgaris L. cv. Black Valentine) for 2 hours to 2.9 microliters per liter SOâ inhibited the net photosynthetic rate an average of 75% and, simultaneously, the translocation rate an average of 45%. Calculations indicated that the experimentally determined translocation rates from SOâ-stressed leaves were lower than were the rates expected on the

K. H. Teh; C. A. Swanson

1982-01-01

210

Butterfly takes flight: the translocal circulation of creative practice  

Microsoft Academic Search

This article analyses the relationship between artistic practice and mobility through a focus on the translocal circulation of theatre. It works against the assumption that art and its creative practices are tied to particular contexts. Instead I suggest that examining translocal connection provides a framework through which to consider how practices of art-making are emplaced and differentiated, whilst also encompassing

Amanda Rogers

2011-01-01

211

Factors Influencing Success of Greenback Cutthroat Trout Translocations  

Microsoft Academic Search

Native subspecies of cutthroat trout Oncorhynchus clarki have declined drastically because of the introduction of nonnative salmonids, overharvesting, and habitat degradation. Conservation of most declining subspecies will include establishing new populations through translocation of genetically pure fish. Recovery of greenback cutthroat trout O. clarki stomias has been ongoing for 25 years, so the attempted translocations of this subspecies provide unique

Amy L. Harig; Kurt D. Fausch; Michael K. Young

2000-01-01

212

Frequent chromosomal translocations induced by DNA double-strand breaks  

Microsoft Academic Search

The faithful repair of DNA damage such as chromosomal double-strand breaks (DSBs) is crucial for genomic integrity. Aberrant repair of these lesions can result in chromosomal rearrangements, including translocations, which are associated with numerous tumours. Models predict that some translocations arise from DSB-induced recombination in differentiating lymphoid cell types or from aberrant repair of DNA damage induced by irradiation or

Christine Richardson; Maria Jasin

2000-01-01

213

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

214

Visual Outcomes Following Macular Translocation With 360° Peripheral Retinectomy  

Microsoft Academic Search

Objective: To evaluate visual outcomes following macu- lar translocation with 360° peripheral retinectomy in pa- tients with subfoveal choroidal neovascularization sec- ondary to age-related macular degeneration. Methods: In a prospective study, 15 consecutive pa- tients with large subfoveal choroidal neovascularization underwent macular translocation with 360° peripheral retinectomy and silicone oil tamponade. Preoperative and postoperative photographs and fluorescein angiograms were obtained

James C. Lai; Deborah J. Lapolice; Sandra S. Stinnett; Carsten H. Meyer; Luz M. Arieu; Melissa A. Keller; Cynthia A. Toth

2002-01-01

215

Proton translocation by bacteriorhodopsin and heme-copper oxidases  

Microsoft Academic Search

Proton translocation is the means by which free energy is conserved from oxygen reduction by the respiratory heme-copper oxidases and from sunlight by bacteriorhodopsin. Three-dimensional structures at atomic resolution of both proteins have aided functional studies of the proton translocation mechanism. A comparison reveals common structural and functional features that may be unique to the primary proton pumps in biology.

Mårten Wikström

1998-01-01

216

Micro-evolution in grasshoppers mediated by polymorphic robertsonian translocations.  

PubMed

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. PMID:23909914

Colombo, Pablo C

2013-01-01

217

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

218

Meiotic Behaviour and Spermatogenesis in Male Mice Heterozygous for Translocation Types Also Occurring in Man.  

National Technical Information Service (NTIS)

In this thesis a start was made with meiotic observations of mouse translocation types - a Robertsonian translocation and a translocation between a metacentric and an acrocentric chromosome - which also occur in man. As an exogeneous factor of possible in...

J. H. Nijhoff

1981-01-01

219

Strandwise translocation of a DNA glycosylase on undamaged DNA  

PubMed Central

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.

2012-01-01

220

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

221

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

222

Translocation events in a single-walled carbon nanotube  

NASA Astrophysics Data System (ADS)

Translocation of DNA oligomers through a single-walled carbon nanotube was demonstrated recently. Translocation events are accompanied by giant current pulses, the origin of which remains obscure. Here, we show that the introduction of a nucleotide, guanosine triphosphate, alone into the input reservoir of a carbon nanotube nanofluidic device also gives giant current pulses. Taken together with data on oligomer translocation, these new results suggest that the pulse width has a nonlinear, power-law dependence on the number of nucleotides in a DNA molecule. We have also measured the time for the onset of DNA translocation pulses after bias reversal, finding that the time for the onset of translocation is directly proportional to the period of the bias reversal.

He, Jin; Liu, Hao; Pang, Pei; Cao, Di; Lindsay, Stuart

2010-11-01

223

Biological aerosol background characterization  

NASA Astrophysics Data System (ADS)

To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

Blatny, Janet; Fountain, Augustus W., III

2011-05-01

224

Cosmic Microwave Background  

NASA Astrophysics Data System (ADS)

Large plasma redshifts of photons in hot, sparse plasma are given by ln ( 1+z )=3.326ot 10-25ot int_0^R N_eot dx., provided the wavelength ? ? ?_0.5 =3.185ot 10-6ot ( 1+1.296ot 10^5ot B^2/Ne )ot ? N_e/T cm, where Ne is the electron density in cm-3, T the temperature in K, R the distance in cm to the emitter, and B the magnetic field in Gauss. The cut-off at ? _0.5 means that the redshift is 50% of its full value. The theory is based on an overlooked interaction of photons with hot sparse electron plasma. It has been overlooked, because the necessary conditions (high temperature and low densities over extended dimensions) cannot be created in the laboratory. The plasma redshifts help explain: the heating of the transition to the corona, the coronal heating, solar redshifts (which invalidate the equivalence principle), galactic redshifts, the heating of galactic corona, the redshifts of white dwarfs and quasars, the cosmological redshifts, and the recently discovered dimming of distant super nova. This presentation will show how plasma redshift also helps explain the cosmic microwave background.

Brynjolfsson, Ari

2003-04-01

225

Human balanced translocation and mouse gene inactivation implicate Basonuclin 2 in distal urethral development  

PubMed Central

We studied a man with distal hypospadias, partial anomalous pulmonary venous return, mild limb-length inequality and a balanced translocation involving chromosomes 9 and 13. To gain insight into the etiology of his birth defects, we mapped the translocation breakpoints by high-resolution comparative genomic hybridization (CGH), using chromosome 9- and 13-specific tiling arrays to analyze genetic material from a spontaneously aborted fetus with unbalanced segregation of the translocation. The chromosome 13 breakpoint was ?400?kb away from the nearest gene, but the chromosome 9 breakpoint fell within an intron of Basonuclin 2 (BNC2), a gene that encodes an evolutionarily conserved nuclear zinc-finger protein. The BNC2/Bnc2 gene is abundantly expressed in developing mouse and human periurethral tissues. In all, 6 of 48 unrelated subjects with distal hypospadias had nine novel nonsynonymous substitutions in BNC2, five of which were computationally predicted to be deleterious. In comparison, two of 23 controls with normal penile urethra morphology, each had a novel nonsynonymous substitution in BNC2, one of which was predicted to be deleterious. Bnc2?/? mice of both sexes displayed a high frequency of distal urethral defects; heterozygotes showed similar defects with reduced penetrance. The association of BNC2 disruption with distal urethral defects and the gene's expression pattern indicate that it functions in urethral development.

Bhoj, Elizabeth J; Ramos, Purita; Baker, Linda A; Cost, Nicholas; Nordenskjold, Agneta; Elder, Frederick F; Bleyl, Steven B; Bowles, Neil E; Arrington, Cammon B; Delhomme, Brigitte; Vanhoutteghem, Amandine; Djian, Philippe; Zinn, Andrew R

2011-01-01

226

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

227

A DNA-translocating Snf2 molecular motor: Saccharomyces cerevisiae Rdh54 displays processive translocation and extrudes DNA loops.  

PubMed

We have used total internal reflection fluorescence microscopy (TIRFM) to investigate the characteristics of the yeast homologous recombination factor Rdh54 on DNA. Our results demonstrate translocation of Rdh54 on DNA and extrusion of DNA loops by Rdh54 in an ATP hydrolysis-dependent manner. The translocating Rdh54 was highly processive and displayed a variety of behavior, including variations in translocation rate and distance, pauses, and reversals. We provide evidence that the DNA loops generated encompass an average of 6 kb, and Rdh54 often abruptly releases the extruded DNA. Rdh54 forms a multimeric complex, which we speculate has at least two functionally distinct DNA-binding sites, one of which enables translocation while the other remains anchored to another DNA locale. Our work, together with other recent studies, suggests that translocation-coupled DNA loop extrusion is a common mechanistic feature among the Snf2-family of chromatin-remodeling proteins. PMID:17467735

Prasad, Tekkatte Krishnamurthy; Robertson, Ragan B; Visnapuu, Mari-Liis; Chi, Peter; Sung, Patrick; Greene, Eric C

2007-04-05

228

Chromosome segregation analysis in human embryos obtained from couples involving male carriers of reciprocal or Robertsonian translocation.  

PubMed

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. PMID:23029381

Yilmaz, Ahmet; Zhang, Xiao Yun; Chung, Jin-Tae; Tan, Seang Lin; Holzer, Hananel; Ao, Asangla

2012-09-27

229

Biological dosimetry in a group of radiologists by the analysis of dicentrics and translocations.  

PubMed

The results of a cytogenetic study carried out in a group of nine radiologists are presented. Chromosome aberrations were detected by fluorescence plus Giemsa staining and fluorescence in situ hybridization. Dose estimates were obtained by extrapolating the yield of dicentrics and translocations to their respective dose-effect curves. In seven individuals, the 95% confidence limits of the doses estimated by dicentrics did not include 0 Gy. The 99 dicentrics observed in 17,626 cells gave a collective estimated dose of 115 mGy (95% confidence limits 73-171). For translocations, five individuals had estimated doses that were clearly higher than the total accumulated recorded dose. The 82 total apparently simple translocations observed in 9722 cells gave a collective estimated dose of 275 mGy (132-496). The mean genomic frequencies (x100 +/- SE) of complete and total apparently simple translocations observed in the group of radiologists (1.91 +/- 0.30 and 2.67 +/- 0.34, respectively) were significantly higher than those observed in a matched control group (0.53 +/- 0.10 and 0.87 +/- 0.13, P < 0.01 in both cases) and in another occupationally exposed matched group (0.79 +/- 0.12 and 1.14 +/-0.14, P < 0.03 and P < 0.01, respectively). The discrepancies observed between the physically recorded doses and the biologically estimated doses indicate that the radiologists did not always wear their dosimeters or that the dosimeters were not always in the radiation field. PMID:16238438

Montoro, A; Rodríguez, P; Almonacid, M; Villaescusa, J I; Verdú, G; Caballín, M R; Barrios, L; Barquinero, J F

2005-11-01

230

Frequency Synthesizer.  

National Technical Information Service (NTIS)

Dual phase lock loops are used to provide a rapid switching, low power, low spurious and fine resolution frequency synthesizer for various radio applications. The first phase lock loop provides for coarse frequency adjustment, and the second phase lock lo...

E. J. Nossen

1978-01-01

231

DNA Translocation Governed by Interactions with Solid-State Nanopores  

PubMed Central

We investigate the voltage-driven translocation dynamics of individual DNA molecules through solid-state nanopores in the diameter range 2.7–5 nm. Our studies reveal an order of magnitude increase in the translocation times when the pore diameter is decreased from 5 to 2.7 nm, and steep temperature dependence, nearly threefold larger than would be expected if the dynamics were governed by viscous drag. As previously predicted for an interaction-dominated translocation process, we observe exponential voltage dependence on translocation times. Mean translocation times scale with DNA length by two power laws: for short DNA molecules, in the range 150–3500 bp, we find an exponent of 1.40, whereas for longer molecules, an exponent of 2.28 dominates. Surprisingly, we find a transition in the fraction of ion current blocked by DNA, from a length-independent regime for short DNA molecules to a regime where the longer the DNA, the more current is blocked. Temperature dependence studies reveal that for increasing DNA lengths, additional interactions are responsible for the slower DNA dynamics. Our results can be rationalized by considering DNA/pore interactions as the predominant factor determining DNA translocation dynamics in small pores. These interactions markedly slow down the translocation rate, enabling higher temporal resolution than observed with larger pores. These findings shed light on the transport properties of DNA in small pores, relevant for future nanopore applications, such as DNA sequencing and genotyping.

Wanunu, Meni; Sutin, Jason; McNally, Ben; Chow, Andrew; Meller, Amit

2008-01-01

232

Does translocation influence physiological stress in the desert tortoise?  

USGS Publications Warehouse

Wildlife translocation is increasingly used to mitigate disturbances to animals or habitat due to human activities, yet little is known about the extent to which translocating animals causes stress. To understand the relationship between physiological stress and translocation, we conducted a multiyear study (2007–2009) using a population of desert tortoises (Gopherus agassizii) near Fort Irwin, California. Blood samples were collected from adult tortoises in three treatment groups (resident, translocated and control) for 1 year prior to and 2 years after translocation. Samples were analyzed by radioimmunoassay for plasma total corticosterone (CORT), a glucocorticoid hormone commonly associated with stress responses in reptiles. CORT values were analyzed in relation to potential covariates (animal sex, date, behavior, treatment, handling time, air temperature, home-range size, precipitation and annual plant production) among seasons and years. CORT values in males were higher than in females, and values for both varied monthly throughout the activity season and among years. Year and sex were strong predictors of CORT, and translocation explained little in terms of CORT. Based on these results, we conclude that translocation does not elicit a physiological stress response in desert tortoises.

Drake, K. K.; Nussear, K. E.; Esque, T. C.; Barber, A. M.; Vittum, K. M.; Medica, P. A.; Tracy, C. R.; Hunter, K. W.

2012-01-01

233

Translocation of gut flora and its role in sepsis.  

PubMed

Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and the internal organs. Sometimes instead of bacteria, inflammatory compounds are responsible for clinical symptoms as in systemic inflammatory response syndrome (SIRS). The difference between sepsis and SIRS is that pathogenic bacteria are isolated from patients with sepsis but not with those of SIRS. Bacterial translocation occurs more frequently in patients with intestinal obstruction and in immunocompromised patients and is the cause of subsequent sepsis. Factors that can trigger bacterial translocation from the gut are host immune deficiencies and immunosuppression, disturbances in normal ecological balance of gut, mucosal barrier permeability, obstructive jaundice, stress, etc. Bacterial translocation occurs through the transcellular and the paracellular pathways and can be measured both directly by culture of mesenteric lymph nodes and indirectly by using labeled bacteria, peripheral blood culture, detection of microbial DNA or endotoxin and urinary excretion of non-metabolisable sugars. Bacterial translocation may be a normal phenomenon occurring on frequent basis in healthy individuals without any deleterious consequences. But when the immune system is challenged extensively, it breaks down and results in septic complications at different sites away from the main focus. The factors released from the gut and carried in the mesenteric lymphatics but not in the portal blood are enough to cause multi-organ failure. Thus, bacterial translocation may be a promoter of sepsis but not the initiator. This paper reviews literature on the translocation of gut flora and its role in causing sepsis. PMID:24064638

Vaishnavi, C

234

Sites of Absorption and Translocation of Iron in Barley Roots  

PubMed Central

Absorption and translocation of labeled Fe were measured at various locations along the length of intact seminal axes and lateral roots of iron-sufficient (+Fe) and iron-stressed (?Fe) barley (Hordeum vulgare) plants. In seminal axes of +Fe plants, rates of translocation were very much higher in a zone 1 to 4 cm from the root tip than elsewhere in the root. Lateral roots of high rates of translocation were also restricted to a narrow band of maturing or recently matured cells. In ?Fe plants the patterns of uptake and translocation were essentially the same as in +Fe plants but the rates were 7- to 10-fold higher. The amount of labeled Fe bound to the root itself was not increased by Fe stress and its distribution along the root seemed inversely related to the ability to translocate Fe. Microautoradiographic studies showed that most of the iron bound to roots was held in an extracellular peripheral band in which iron seemed to be precipitated. This process may be assisted by microbial colonies but did not depend on them since it was seen, although to a lesser extent, in sterile roots. In zones from which iron was translocated there was evidence that internal root tissues became labeled readily, but as translocation declined with distance from the root tip, radial penetration of Fe appeared to become progressively less. The results are discussed in relation to possible changes in the pH or redox potential of the surface of the root. ImagesFIG. 5

Clarkson, David T.; Sanderson, John

1978-01-01

235

Sizing the Protein Translocation Pathway of Colicin Ia Channels  

PubMed Central

The bacterial toxin colicin Ia forms voltage-gated channels in planar lipid bilayers. The toxin consists of three domains, with the carboxy-terminal domain (C-domain) responsible for channel formation. The C-domain contributes four membrane-spanning segments and a 68-residue translocated segment to the open channel, whereas the upstream domains and the amino-terminal end of the C-domain stay on the cis side of the membrane. The isolated C-domain, lacking the two upstream domains, also forms channels; however, the amino terminus and one of the normally membrane-spanning segments can move across the membrane. (This can be observed as a drop in single-channel conductance.) In longer carboxy-terminal fragments of colicin Ia that include ?169 residues upstream from the C-domain, the entire upstream region is translocated. Presumably, a portion of the C-domain creates a pathway for the polar upstream region to move through the membrane. To determine the size of this translocation pathway, we have attached “molecular stoppers,” small disulfide-bonded polypeptides, to the amino terminus of the C-domain, and determined whether they could be translocated. We have found that the translocation rate is strongly voltage dependent, and that at voltages ?90 mV, even a 26-Å stopper is translocated. Upon reduction of their disulfide bonds, all of the stoppers are easily translocated, indicating that it is the folded structure, rather than some aspect of the primary sequence, that slows translocation of the stoppers. Thus, the pathway for translocation is ?26 Å in diameter, or can stretch to this value. This is large enough for an ?-helical hairpin to fit through.

Kienker, Paul K.; Jakes, Karen S.; Blaustein, Robert O.; Miller, Christopher; Finkelstein, Alan

2003-01-01

236

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

237

June 29, 2012: Background Materials  

Center for Biologics Evaluation and Research (CBER)

... Drug Administration. -. June 29, 2012: Background Materials. -. June 29, 2012: Background Information Memo. -. -. -. Page Last ... More results from www.fda.gov/advisorycommittees/committeesmeetingmaterials/riskcommunicationadvisorycommittee

238

Translocator Receptor Blockade Reduces Prostate Tumor Growth  

PubMed Central

Statement of Translational Relevance Although benzodiazepines have been used clinically for over 50 years, their application as a form of cancer therapy is largely unexplored. Here we show that lorazepam, a benzodiazepine commonly prescribed to treat anxiety disorders and acts on both central and peripheral receptors, inhibits prostate cancer cell growth and survival. Our studies further elucidate the mechanism by which Translocator Protein (TSPO) antagonists alter cancer cell function. Antagonists for TSPO are already used in the clinic for other indications and demonstrate very minor side effects. Because lorazepam is a commonly prescribed FDA-approved drug, the translation of our preclinical results to the prostate cancer patient population could be readily achieved. Our studies could lead to a significant change in the management of prostate cancer by providing a treatment option with minimal toxicity for use after failure of androgen-deprivation therapy and could ultimately prevent prostate cancer deaths. Purpose The transmembrane molecule, Translocator Protein (TSPO) has been implicated in the progression of epithelial tumors. TSPO gene expression is high in tissues involved in steroid biosynthesis, neurodegenerative disease and in cancer and overexpression has been shown to contribute to pathologic conditions including cancer progression in several different models. The goal of our study was to examine the expression and biological relevance of TSPO in prostate cancer and demonstrate that the commonly prescribed benzodiazepine lorazepam, a ligand for TSPO, exhibits anti-cancer properties. Experimental Design Immunohistochemical analysis using tissue microarrays was used to determine the expression profile of TSPO in human prostate cancer tissues. To demonstrate the effect of benzodiazepines (lorazepam and PK11195) in prostate cancer, we utilized cell proliferation assays, apoptosis ELISA, prostate cancer xenograft study, and immunohistochemistry. Results TSPO expression is increased in prostatic intraepithelial neoplasia, primary prostate cancer, and metastases compared to normal prostate tissue and benign prostatic hyperplasia. Furthermore, TSPO expression correlates with disease progression, as TSPO levels increased with increasing Gleason sum and stage with prostate cancer metastases demonstrating the highest level of expression among all tissues examined. Functionally, we have demonstrated that lorazepam has anti-proliferative and pro-apoptotic properties in vitro and in vivo. Additionally, we have shown that TSPO overexpression in nontumorigenic cells conferred susceptibility to lorazepam-induced growth inhibition. Conclusion These data suggest that blocking TSPO function in tumor cells induces cell death and denotes a survival role for TSPO in prostate cancer and provide the first evidence for the use of benzodiazepines in prostate cancer therapeutics.

Fafalios, Arlee; Akhavan, Ardavan; Parwani, Anil V.; Bies, Robert R.; McHugh, Kevin J.; Pflug, Beth R.

2009-01-01

239

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

240

Mechanical design of translocating motor proteins.  

PubMed

Translocating motors generate force and move along a biofilament track to achieve diverse functions including gene transcription, translation, intracellular cargo transport, protein degradation, and muscle contraction. Advances in single molecule manipulation experiments, structural biology, and computational analysis are making it possible to consider common mechanical design principles of these diverse families of motors. Here, we propose a mechanical parts list that include track, energy conversion machinery, and moving parts. Energy is supplied not just by burning of a fuel molecule, but there are other sources or sinks of free energy, by binding and release of a fuel or products, or similarly between the motor and the track. Dynamic conformational changes of the motor domain can be regarded as controlling the flow of free energy to and from the surrounding heat reservoir. Multiple motor domains are organized in distinct ways to achieve motility under imposed physical constraints. Transcending amino acid sequence and structure, physically and functionally similar mechanical parts may have evolved as nature's design strategy for these molecular engines. PMID:19452133

Hwang, Wonmuk; Lang, Matthew J

2009-05-19

241

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

242

Ion-translocating properties of calcifiable proteolipids  

SciTech Connect

De novo formation of calcium hydroxyapatite in biological systems occurs on membrane surfaces through specific interactions of Ca, Pi, phospholipids, calcifiable proteolipids, and ion flux to and from the nucleating site. This paper reports an in vitro model demonstrating an ion transport function for calcifiable proteolipid. Bacterionema matruchotii proteolipid was incubated with a radiolabeled H+-channel inhibitor, 14C-dicyclohexyl-carbodiimide, and binding characterized by displacement studies with DCCD or ethyldimethylaminopropylcarbodiimide. A carboxyl binding site was suggested by displacement of DCCD by the nucleophile, glycine ethyl ester. The displacement studies indicated that proteolipid bound DCCD via carboxyl group interaction in a hydrophobic region of the protein. SDS-polyacrylamide gel electrophoresis showed that all label was associated with a single band of 8500 Mr. No non-specific binding of 14C-DCCD to phospholipids occurred, since all bound label was associated with protein following Sephadex LH-20 chromatography of crude proteolipid. Phospholipid liposomes were prepared containing bacteriorhodopsin and proteolipid or proteolipid-14C-DCCD, via cholate dialysis. Transmembrane pH changes established by the bacteriorhodopsin H+ pump were measured in the presence and absence of added proteolipid. Proteolipid had an effect similar to those of uncouplers such as tetraphenylboron. Both the rate and extent of proton translocation increased following addition of proteolipid to BR-liposomes. 14C-DCCD abolished the proteolipid-augmented ion transport. When tetraphenylboron was used to abolish the transmembrane electrical potential, calcifiable proteolipid did not augment proton transport.

Swain, L.D.; Boyan, B.D.

1988-03-01

243

COMMUNICATION: Resonant activation in polymer translocation: new insights into the escape dynamics of molecules driven by an oscillating field  

NASA Astrophysics Data System (ADS)

The translocation of molecules across cellular membranes or through synthetic nanopores is strongly affected by thermal fluctuations. In this work we study how the dynamics of a polymer in a noisy environment changes when the translocation process is driven by an oscillating electric field. An improved version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics, by taking into account the harmonic interactions between adjacent monomers and the excluded-volume effect by introducing a Lennard-Jones potential between all beads. A bending recoil torque has also been included in our model. The polymer dynamics is simulated in a two-dimensional domain by numerically solving the Langevin equations of motion. Thermal fluctuations are taken into account by introducing a Gaussian uncorrelated noise. The mean first translocation time of the polymer centre of inertia shows a minimum as a function of the frequency of the oscillating forcing field. This finding represents the first evidence of the resonant activation behaviour in the dynamics of polymer translocation.

Pizzolato, N.; Fiasconaro, A.; Persano Adorno, D.; Spagnolo, B.

2010-09-01

244

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

245

Sperm analysis by FISH in a case of t(17; 22) (q11; q12) balanced translocation: case report.  

PubMed

Individual sperm from men with balanced translocations have different chromosomal contents. Thus, an estimation of the overall sperm chromosomal imbalance of such patients could help to give the couple an adapted genetic counselling. We report here the study of a balanced translocation carrier, t(17;22) (q11;q12) whose reproductive history reported four miscarriages. Moreover, he had an abnormal semen analysis with oligoteratozoospermia. The meiotic segregation pattern was examined in 700 sperm, using fluorescence in-situ hybridization (FISH). Nineteen percent of the sperm had balanced translocations or were normal. All other sperm were unbalanced (81%) and their distribution was observed as follows: the frequencies of adjacent 1, adjacent 2 and 3:1 segregations were 12.9, 5.8 and 46.8% respectively. Among the segregations scored, 13.7% were related to second meiotic division abnormalities. Less than 2% of the total sperm scored were not explained. The 3:1 segregation was present at a very high rate, which is very unusual. In cases of balanced translocations, we believe that no general features can be drawn. Thus, the FISH technique may be very helpful for genetic counselling, which remains an important step and must be done with care. PMID:11821272

Geneix, Aimé; Schubert, Benoît; Force, André; Rodet, Karen; Briançon, Georges; Boucher, Daniel

2002-02-01

246

Resonant activation in polymer translocation: new insights into the escape dynamics of molecules driven by an oscillating field.  

PubMed

The translocation of molecules across cellular membranes or through synthetic nanopores is strongly affected by thermal fluctuations. In this work we study how the dynamics of a polymer in a noisy environment changes when the translocation process is driven by an oscillating electric field. An improved version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics, by taking into account the harmonic interactions between adjacent monomers and the excluded-volume effect by introducing a Lennard-Jones potential between all beads. A bending recoil torque has also been included in our model. The polymer dynamics is simulated in a two-dimensional domain by numerically solving the Langevin equations of motion. Thermal fluctuations are taken into account by introducing a Gaussian uncorrelated noise. The mean first translocation time of the polymer centre of inertia shows a minimum as a function of the frequency of the oscillating forcing field. This finding represents the first evidence of the resonant activation behaviour in the dynamics of polymer translocation. PMID:20686190

Pizzolato, N; Fiasconaro, A; Adorno, D Persano; Spagnolo, B

2010-08-04

247

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

PubMed Central

Controversy regarding potential health risks from increased use of medical diagnostic radiologic examinations has come to public attention. We evaluated whether chromosome damage, specifically translocations, which are a potentially intermediate biomarker for cancer risk, was increased after exposure to diagnostic X-rays, with particular interest in the ionizing radiation dose–response below the level of approximately 50 mGy. Chromosome translocation frequency data from three separately conducted occupational studies of ionizing radiation were pooled together. Studies 1 and 2 included 79 and 150 medical radiologic technologists, respectively, and study 3 included 83 airline pilots and 50 university faculty members (total = 155 women and 207 men; mean age = 62 years, range 34–90). Information on personal history of radiographic examinations was collected from a detailed questionnaire. We computed a cumulative red bone marrow (RBM) dose score based on the numbers and types of X-ray examinations reported with 1 unit approximating 1 mGy. Poisson regression analyses were adjusted for age and laboratory method. Mean RBM dose scores were 49, 42, and 11 for Studies 1–3, respectively (overall mean = 33.5, range 0–303). Translocation frequencies significantly increased with increasing dose score (P < 0.001). Restricting the analysis to the lowest dose scores of under 50 did not materially change these results. We conclude that chromosome damage is associated with low levels of radiation exposure from diagnostic X-ray examinations, including dose scores of approximately 50 and lower, suggesting the possibility of long-term adverse health effects.

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

2011-01-01

248

Characterization of DNA Translocation and Detection in Functionalized Nanopores  

NASA Astrophysics Data System (ADS)

Functionalized nanopores have been used in selective detective of DNA. While the interaction between a bare nanopore and a DNA has been analyzed extensively, little is know for that of a functionalized nanopore. This work focuses on studying the DNA translocation dynamics and mechanism of DNA sequencing in a functionalized nanopore through a coarse-grained molecular dynamics model. Physical properties of chemically modified nanopores, i.e., the effective pore diameter under different bias voltages are characterized. The DNA translocation dynamics under different nanopore coatings and different bias voltages are studied. The simulation results reveal that molecular selective translocation larges lies on the flexibility and orientation of the coating molecules and their interaction with the translocating DNA. This research supports rational designs of DNA transportation- and manipulation-based diagnostic systems.

Liu, Yaling; Ramachandran, Abhijit

2010-03-01

249

Characterization of DNA Translocation and Detection in Functionalized Nanopores  

NASA Astrophysics Data System (ADS)

Functionalized nanopores have been used in selective detective of DNA. While the interaction between a bare nanopore and a DNA has been analyzed extensively, little is know for that of a functionalized nanopore. This work focuses on studying the DNA translocation dynamics and mechanism of DNA sequencing in a functionalized nanopore through a coarse-grained molecular dynamics model. Physical properties of chemically modified nanopores, i.e., the effective pore diameter under different bias voltages are characterized. The DNA translocation dynamics under different nanopore coatings and different bias voltages are studied. The simulation results reveal that molecular selective translocation larges lies on the flexibility and orientation of the coating molecules and their interaction with the translocating DNA. This research supports rational designs of DNA transportation- and manipulation-based diagnostic systems.

Liu, Yaling; Ramachandran, Abhijit; Guo, Qingjiang

2011-03-01

250

Elucidating the Role of Translocator Protein in Prostate Cancer.  

National Technical Information Service (NTIS)

Purpose: To determine the functional role of Translocator Protein (TSPO) in prostate cancer progression. Scope: To demonstrate the effect of TSPO ligands in prostate cancer, we utilized cell proliferation assays, apoptosis ELISAs, and a prostate cancer mo...

A. Fafalios B. R. Pflug

2009-01-01

251

Kinetics of Motor Protein Translocation on Single Stranded DNA  

PubMed Central

The translocation of nucleic acid motor proteins along DNA or RNA can be studied in ensemble experiments by monitoring either the kinetics of the arrival of the protein at a specific site on the nucleic acid filament (generally one end of the filament) or the kinetics of ATP hydrolysis by the motor protein during translocation. The pre-steady state kinetic data collected in ensemble experiments can be analyzed by simultaneous global non-linear least squares (NLLS) analysis using a simple sequential “n-step” mechanism to obtain estimates of the rate-limiting step(s) in the translocation cycle, the average “kinetic step-size”, and efficiency of coupling ATP binding and hydrolysis to translocation.

Wooten, Lake; Tomko, Eric J.

2013-01-01

252

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Genetic Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This test detects transmitted...

2013-07-01

253

Leaf Structure and Translocation in Sugar Beet 1  

PubMed Central

Anatomical and ultrastructural details of a translocating 10-cm leaf of sugar beet (Beta vulgaris L. var. Klein Wanzleben) were correlated with translocation rate data. The minor veins were found to be 13 times as extensive as the major veins and measure 70 cm/cm2 leaf lamina. Measurements disclosed that a 33-? length of minor vein services 29 mesophyll cells with the result that translocate moves an average of 73 ? or 2.2 cell diameters during transport from mesophyll cells to a minor vein. High-resolution, freeze-dry autoradiography revealed that assimilates accumulate in organelle-rich cells of the minor vein phloem. Correlation of phloem volume and loading rate for minor veins yielded an uptake rate of 735 ?moles of sucrose per g fresh weight of phloem. The arrangement and structural features of minor veins appeared to be consistent with the concept that vein loading precedes translocation. Images

Geiger, D. R.; Cataldo, D. A.

1969-01-01

254

Pore-blockade times for field-driven polymer translocation  

NASA Astrophysics Data System (ADS)

We study pore-blockade times for a translocating polymer of length N, driven by a field E across the pore in three dimensions. The polymer performs Rouse dynamics, i.e., we consider polymer dynamics in the absence of hydrodynamical interactions. We find that the typical time for which the pore remains blocked during a translocation event scales as ~N(1+2?)/(1+?)/E, where \

Vocks, Henk; Panja, Debabrata; Barkema, Gerard T.; Ball, Robin C.

2008-03-01

255

Chromosomal segregation in spermatozoa of 14 Robertsonian translocation carriers  

Microsoft Academic Search

Male carriers of Robertsonian (Rob) translocations can have fertility problems associated with low sperm counts and abnormal sperm morphology. In this study, spermatozoa from 14 Rob translocation carriers, seven der(13;14), two der(13;15), two der(14;15), two der(14;21) and one der(21;22), were tested by fluorescence in-situ hybridization (FISH) for the chromosomes involved, to study meiotic segregation behaviour. It was shown that in

Gonul Ogur; Elvire Van Assche; Walter Vegetti; Greta Verheyen; Herman Tournaye; Maryse Bonduelle; André Van Steirteghem; Inge Liebaers

2006-01-01

256

DNA Translocation Governed by Interactions with Solid-State Nanopores  

Microsoft Academic Search

We investigate the voltage-driven translocation dynamics of individual DNA molecules through solid-state nanopores in the diameter range 2.7–5nm. Our studies reveal an order of magnitude increase in the translocation times when the pore diameter is decreased from 5 to 2.7nm, and steep temperature dependence, nearly threefold larger than would be expected if the dynamics were governed by viscous drag. As

Meni Wanunu; Jason Sutin; Ben McNally; Andrew Chow; Amit Meller

2008-01-01

257

Proton translocation by bacteriorhodopsin and heme-copper oxidases.  

PubMed

Proton translocation is the means by which free energy is conserved from oxygen reduction by the respiratory heme-copper oxidases and from sunlight by bacteriorhodopsin. Three-dimensional structures at atomic resolution of both proteins have aided functional studies of the proton translocation mechanism. A comparison reveals common structural and functional features that may be unique to the primary proton pumps in biology. PMID:9729741

Wikström, M

1998-08-01

258

Effect of salinity on translocation of assimilates in french bean  

Microsoft Academic Search

The effect of sodium chloride and sodium sulphate salinities on the rate of translocation of photosynthates in french bean\\u000a at the pod filling stage was investigated. Both salt treatments exerted a negative influence on the translocation of photosynthetic\\u000a assimilates and in this respect the NaCl treatment was more detrimental than that of Na2SO4. The transport of radioactivity from the source

V. N. Bhivare; P. D. Chavan

1987-01-01

259

Cryptic translocation t(5;18) in familial mental retardation  

Microsoft Academic Search

A cryptic translocation t(5;18)(qter;qter) was detected in a large family, using a FISH-based approach combining subtelomeric probes to allow the subtelomeric regions of most chromosome ends to be analysed for deletions and balanced or unbalanced translocations. Unbalanced karyotypes (duplication 5qter\\/deficiency 18qter) resulted in a previously undescribed association of moderate to severe mental retardation, microcephaly, pre- and postnatal growth retardation, distinct

Annick Vogels; Koen Devriendt; Joris R Vermeesch; Roeland Van Dael; Peter Marynen; Paul Dewaele; Jozef Hageman; Maureen Holvoet; Jean-Pierre Fryns

2000-01-01

260

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

261

DNA translocation through protein and synthetic nano pores  

NASA Astrophysics Data System (ADS)

DNA translocation through narrow protein channels is recognized as an important process in biology. Recently it has attracted lot of attention in the biophysical community following several experiments on DNA translocation through protein nano-pores, and more recently, through synthetic silicon nano-pores. A fundamental understanding is needed for various biological processes, e.g., entry and exit of a DNA in and out of a cell, efficient separation methods for macromolecules, and, possibly fast DNA sequencing. In this talk I will be presenting results for the DNA translocation using a coarse-grained model for an idealized DNA as well as the pore. I will consider several scenarios for the DNA translocation. First, I will show scaling of translocation time of a homopolymer as it escapes from the trans side to the cis side of an idealized thin membrane. Then I will consider DNA dynamics subject to a driving force inside the pore. Next, I will consider heteropolymer threading through a nano-pore. Specifically we will consider both highly ordered and completely random sequences of the chain and relate specific sequences to the distribution of the translocation time and the residence time inside the pore. These studies also will include effects due to different environment on either side of the pore, specific DNA-pore interactions located at selective sites, etc.. I will discuss relevance of these simulation results to recent experiments and theoretical models. A. Milchev, K. Binder, and Aniket Bhattacharya, J. Chem. Phys. 121, 6042 (2004).

Bhattacharya, Aniket

2007-03-01

262

Dominant-lethal mutation and heritable translocation tests in mice  

SciTech Connect

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. Chromosome breakage can result in chromosome loss, which often leads to embryonic lethality and occassionally to viable aneuploids, or to viable reciprocal translocations and inversions. In mice, transmitted chromosome breakage effects may be measured by using dominant-lethal mutations, heritable translocations, heritable inversions, sex-chromosome loss, and chromosome breakage and rearrangement scored cytologically in early embryos. The dominant-lethal mutation and the heritable translocation tests are the most widely used tests. The heritable translocation procedure described here applies only to the induction of translocations in male germ cells. The use of treated females in the dominant-lethal test has its drawback too. When the fertility of treated female is reduced or when embryonic lethality is observed, it is difficult to ascertain whether these effects are attributable to true genetic damage or to physiological imbalances in the treated females. Therefore the dominant-lethal test as it is used in practical testing has almost exclusively employed the treatment of males. This is not to say that treatment of females has no advantages whatsoever. On the contrary, there is a good example of a case whereby dominant-lethal effects of the test compound was unequivocably demonstrated in treated females but not in treated males.

Generoso, W.M.

1980-01-01

263

Dermatoglyphs in carriers of a balanced 15;21 translocation.  

PubMed Central

Cytogenetic and dermatoglyphic features were studied in a large family with an inherited 15;21 translocation. Of 35 healthy members of the family, 21 carried the translocation chromosome and 14 were chromosomally normal. There were six members with Down's syndrome who had the translocation. Dermatoglyphic studies showed that carriers of this balanced translocation had the following peculiarities significantly more often than the general population. On the hands, they had ulnar loops on the fingertips, symmetrical high terminations of the A line, symmetrical ulnar loops on the hypothenar areas, distal loops in the 3rd interdigital areas, open fields in the 4th interdigital areas, axial triradii in the distal position, and single transverse palmar creases (Sydney lines). On the feet, they had small distal loops on the hallucal area and distal loops in the 4th interdigital areas. The translocation carriers also had significantly more often than non-carrier relatives symmetrical high terminations of the A line, open fields in the 4th interdigital areas, distal axial triradii, and Sydney lines. On the feet, they had small distal loops on the hallucal areas, distal loops in the 4th interdigital areas, and tibial loops on the proximal hypothenar areas. The data obtained from this study, and especially the values of the Walker and general indices, indicate that some of the dermatoglyphic stigmata of Down's syndrome are directly associated with the 15;21 translocation carrier state and can therefore be used for predicting that state.

Rodewald, A; Zankl, M; Zankl, H; Zang, K D

1980-01-01

264

The role of translocation in recovery of woodland caribou populations.  

PubMed

Maintenance of viable populations of many endangered species will require conservation action in perpetuity. Efforts to conserve these species are more likely to be successful if their reliance on conservation actions is assessed at the population level. Woodland caribou (Rangifer tarandus caribou) were extirpated recently from Banff National Park, Canada, and translocations of caribou to Banff and neighboring Jasper National Park are being considered. We used population viability analysis to assess the relative need for and benefits from translocation of individuals among caribou populations. We measured stochastic growth rates and the probability of quasi extinction of four populations of woodland caribou with and without translocation. We used two vital rates in our analysis: mean adult female survival and mean number of calves per breeding-age female as estimates of mean fecundity. We isolated process variance for each vital rate. Our results suggested the Tonquin caribou population in Jasper is likely to remain viable without translocation, but that translocation is probably insufficient to prevent eventual extirpation of the two other populations in Jasper. Simulated reintroductions of caribou into Banff resulted in a 53-98% probability of >8 females remaining after 20 years, which suggests translocation may be an effective recovery tool for some caribou populations. PMID:21091770

Decesare, Nicholas J; Whittington, Jesse; Hebblewhite, Mark; Robinson, Hugh; Bradley, Mark; Neufeld, Lalenia; Musiani, Marco

2010-11-17

265

Protein kinase C translocation in human blood platelets  

SciTech Connect

Protein kinase C (PKC) activity and translocation in response to the phorbol ester, phorbol 12-myristate, 13-acetate (PMA), serotonin (5-HT) and thrombin was assessed in human platelets. Stimulation with PMA and 5-HT for 10 minutes or thrombin for 1 minute elicited platelet PKC translocation from cytosol to membrane. The catecholamines, norepinephrine or epinephrine at 10 {mu}M concentrations did not induce redistribution of platelet PKC. Serotonin and the specific 5-HT{sub 2} receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-amino-propane (DOI) but not the 5-HT{sub 1A} or 5-HT{sub 1B} agonists, ({plus minus}) 8-hydroxy-dipropylamino-tetralin (8-OH-DPAT) or 5-methoxy-3-3-(1,2,3,6-tetrahydro-4-pyridin) 1H-indole succinate (RU 24969) induced dose-dependent PKC translocations. Serotonin-evoked PKC translocation was blocked by selective 5-HT{sub 2} receptor antagonists, ketanserin and spiroperidol. These results suggest that, in human platelets, PMA, thrombin and 5-HT can elicit PKC translocation from cytosol to membrane. Serotonin-induced PKC translocation in platelets is mediated via 5-HT{sub 2} receptors.

Wang, Hoauyan; Friedman, E. (Medical College of Pennsylvania, Philadelphia (USA))

1990-01-01

266

Background  

Center for Drug Evaluation (CDER)

Text Version... with cardiovascular disease or risk factors for cardiovascular ... patients are at greater risk for serious ... PI contains numerous other risks associated with ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

267

Background  

Center for Drug Evaluation (CDER)

Text Version... Problem: You placed a pivotal study under 5.3.1.1, and now you realize it needs to be under 5.3.5.1 y • Solution: – Delete out all the leaf IDs that ... More results from www.fda.gov/downloads/drugs/developmentapprovalprocess

268

Background  

Center for Biologics Evaluation and Research (CBER)

Text Version... 11217 CAR.GD2z Activated T cells vs Neuroblastoma. EBV-CTLs. ... 13296 CAR.CD19.CD28z vs Activated T cells CD19+ Lymphoma. CAR.CD19z. ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

269

Alpha-Lipoic Acid Attenuates Cisplatin-Induced Tubulointerstitial Injuries through Inhibition of Mitochondrial Bax Translocation in Rats  

Microsoft Academic Search

Background: Renal tubule cell apoptosis plays a pivotal role in cisplatin-induced nephrotoxicity. ?-Lipoic acid (LA), a thiol antioxidant, is well known to be cytoprotective in various cell death models through its involvement in the death receptor apoptosis pathway. However, we hypothesized that LA would attenuate cisplatin-induced nephrotoxicity through inhibition of mitochondrial bax translocation in rats. Methods and Materials: Sprague-Dawley rats

Young Mo Lee; So Yon Bae; Nam Hee Won; Heui Jung Pyo; Young Joo Kwon

2009-01-01

270

Translocation of Crohn's disease Escherichia coli across M-cells: contrasting effects of soluble plant fibres and emulsifiers  

Microsoft Academic Search

BackgroundCrohn's disease is common in developed nations where the typical diet is low in fibre and high in processed food. Primary lesions overlie Peyer's patches and colonic lymphoid follicles where bacterial invasion through M-cells occurs. We have assessed the effect of soluble non-starch polysaccharide (NSP) and food emulsifiers on translocation of Escherichia coli across M-cells.MethodsTo assess effects of soluble plant

Carol L Roberts; Åsa V Keita; Sylvia H Duncan; Niamh OKennedy; Johan D Söderholm; Jonathan M Rhodes; Barry J Campbell

2010-01-01

271

Effect of the cGMP pathway on AQP2 expression and translocation: potential implications for nephrogenic diabetes insipidus  

Microsoft Academic Search

BACKGROUND: Arginine vasopressin (AVP) binding to the V2 receptor (V2R) in renal collecting duct principal cells induces a cAMP signalling cascade resulting in the activation of protein kinase A (PKA), translocation of aquaporin-2 (AQP2) to the apical membrane and an increase in AQP2 expression. Consequently, concentration of urine is initiated. X-linked nephrogenic diabetes insipidus (NDI), characterized by the inability to

M. Boone; M. L. A. Kortenoeven; J. H. Robben; P. M. T. Deen

2010-01-01

272

Campylobacter fetus translocation across Caco-2 cell monolayers.  

PubMed

Campylobacter fetus is a recognized pathogen of cattle and sheep, though human infection has also been reported. Ingestion of contaminated food or water is a proposed route of transmission for both humans and animals. The subsequent detection of the organism from extra-intestinal and systemic locations implies an ability to translocate across epithelial barriers. To determine how C. fetus disseminates from the intestine, Caco-2 cells cultured on porous membrane supports, were used as model intestinal epithelial cell monolayers. C. fetus was found to translocate equally well in both apical-to-basolateral and basolateral-to-apical directions for up to 24 h without altering Caco-2 cell monolayer permeability as assessed by transepithelial resistance and absence of paracellular diffusion of FITC-inulin. Using modified antibiotic protection assays, C. fetus was also observed to invade and subsequently egress from Caco-2 cells. Caco-2 cell invasion and translocation occurred independently of C. fetus S layer expression. Scanning and transmission electron microscopy revealed the presence of C. fetus associated with both apical and basal surfaces as well as in intracellular locations. C. fetus was, however, never observed in paracellular locations nor associated with Caco-2 cells junctions. Neither C. fetus invasion nor translocation across Caco-2 cell monolayers was impacted by latrunculin A, though translocation was enhanced in the presence of cytochalasin D which disrupted tight junctions. Tubulin cytoskeleton disrupting agents, colchicine and vinblastine, did inhibit C. fetus translocation though entry into Caco-2 cells remained unaffected. Together, translocation without disrupting monolayer integrity, invasion and egression from Caco-2 cells, electron microscopy observations and the requirement of a functional tubulin cytoskeleton for translocation, support a transcellular mechanism of C. fetus translocation across Caco-2 cell monolayers. The ability to invade and subsequently egress would contribute to establishment of an infecting C. fetus population in the host, while the demonstrated ability to translocate across model intestinal epithelial barriers accounts for the observed in vivo recovery of C. fetus from extra-intestinal locations. PMID:20600794

Baker, N T; Graham, L L

2010-06-23

273

Investigation of a Background Suppression Transimpedance Amplifier for Photovoltaic Detectors.  

National Technical Information Service (NTIS)

The current generation of transimpedance amplifier based detector systems are limited by opamp saturation when operating at a high gain or in the presence of a large background signal. To eliminate saturation, an amplifier that is frequency dependent is d...

F. J. Metzger

1992-01-01

274

Beam induced backgrounds: CDF experience  

SciTech Connect

We summarize the experiences of the Collider Detector at Fermilab (CDF) experiment in the presence of backgrounds originating from the counter circulating beams in the Fermilab Tevatron. These backgrounds are measured and their sources identified. Finally, we outline the strategies employed to reduce the effects of these backgrounds on the experiment.

Tesarek, R.J.; /Fermilab

2008-05-01

275

Reductions in Platelet 18-kDa Translocator Protein Density Are Associated with Adult Separation Anxiety in Patients with Bipolar Disorder  

Microsoft Academic Search

Background: Recent studies indicate that adult separation anxiety disorder is a discrete diagnostic entity and worthy of attention. Previously, we found a significant association between platelet expression of the 18-kDa translocator protein (TSPO) and adult separation anxiety in patients with panic disorder or major depression. The aim of this study was to explore whether adult separation anxiety might be a

Marianna Abelli; Beatrice Chelli; Barbara Costa; Lisa Lari; Alessandra Cardini; Camilla Gesi; Matteo Muti; Antonio Lucacchini; Claudia Martini; Giovanni B. Cassano; Stefano Pini

2010-01-01

276

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

Microsoft Academic Search

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.

Allison A Burrow; Laura E Williams; Yuh-Hwa Wang

2009-01-01

277

TFG, a target of chromosome translocations in lymphoma and soft tissue tumors, fuses to GPR128 in healthy individuals  

PubMed Central

Background The formation of fusion genes plays roles in both oncogenesis and evolution by facilitating the acquisition of novel functions. Here we describe the first example of a human polymorphic in-frame fusion of two unrelated genes associated with a copy number variant. Design and Methods Array comparative genomic hybridization was used to identify cryptic oncogenic fusion genes. Fusion gene structure and origin was examined using molecular biological and computational methods. Phenotype associations were examined using PopGen cohorts. Results Targeted array comparative genomic hybridization to identify cryptic oncogenic fusion genes in patients with atypical myeloproliferative neoplasms identified a 111 kb amplification with breakpoints within the TRK-fused gene (TFG, a target of translocations in lymphoma and thyroid tumors) and G-protein-coupled receptor 128 (GPR128) resulting in an expressed in-frame TFG-GPR128 fusion transcript. The fusion gene was also identified in healthy individuals at a frequency of 0.02 (3/120). Normally both genes are in identical orientations with TFG immediately downstream of GPR128. In individuals with a copy number variant amplification, one or two copies of the TFG-GPR128 fusion are found between the two parental genes. The breakpoints share a region of microhomology, and haplotype and microsatellite analysis indicate a single ancestral origin. Analysis of PopGen cohorts showed no obvious phenotype association. An in silico search of EST databases found no other copy number variant amplification-associated fusion transcripts, suggesting that this is an uncommon event. Conclusions The finding of a polymorphic gene fusion in healthy individuals adds another layer to the complexity of human genome variation and emphasizes the importance of careful discrimination of oncogenic changes found in tumor samples from non-pathogenic normal variation.

Chase, Andrew; Ernst, Thomas; Fiebig, Andreas; Collins, Andrew; Grand, Francis; Erben, Philipp; Reiter, Andreas; Schreiber, Stefan; Cross, Nicholas C.P.

2010-01-01

278

Difference in the ratio of dominant-lethal mutations to heritable translocations produced in mouse spermatids and fully mature sperm after treatment with triethylenemelamine (TEM)  

SciTech Connect

The relative induction of dominant-lethal mutations and heritable translocations in triethylenemelamine-treated male postmeiotic germ cells of mice was determined depending on the stage treated. Males were mated either 11.5 to 14.5 days after treatment (middle spermatids) or less than 2.5 hours after treatment (fully mature sperm). Results clearly showed that, even though similar levels of dominant-lethal mutations were induced in fully mature sperm and in middle spermatids, the frequency of heritable translocations induced in mature sperm was markedly lower than that induced in middle spermatids. This observation was used, together with earlier ones, to suggest a mechanism by which dominant-lethal mutations and heritable translocations are produced following chemical treatment of male postmeiotic germ cels.

Generoso, W.M.; Cain, K.T.; Cornett, C.V.; Russell, E.W.; Hellwig, C.S.; Horton, C.Y.

1982-04-01

279

Xp11.2 translocation renal cell carcinoma.  

PubMed

Xp11.2 translocation renal cell carcinomas (RCCs), a recently recognized distinct subtype, are rare tumors predominantly reported in young patients. They comprise at least one-third of pediatric RCCs, and only few adult cases have been reported. They are characterized by various translocations involving chromosome Xp11.2, all resulting in gene fusions involving the transcription factor E3 (TFE3) gene. In recent years, at least 6 different Xp11.2 translocation RCCs have been identified and characterized at the molecular level. These include a distinctive RCC that bears a translocation with the identical chromosomal breakpoints (Xp11.2, 17q25) and identical resulting ASPL-TFE3 gene fusion as alveolar soft part sarcoma. They typically have papillary or nested architecture and are composed of cells with voluminous, clear, or eosinophilic cytoplasm. Their most distinctive immunohistochemical feature is nuclear labeling for TFE3 protein. Although only limited data are available so far, they are believed to be rather indolent, but there have been increasing, recent reports of an aggressive clinical course in adult cases. The consistent immunohistochemical staining for TFE3 in all RCC with unusual histology, regardless of patient age, is likely to expand the spectrum of Xp11.2 translocation RCC with respect to age, clinical behavior, and molecular abnormalities. PMID:20073616

Armah, Henry B; Parwani, Anil V

2010-01-01

280

Intracellular calcium modulates the nuclear translocation of calsenilin.  

PubMed

Calsenilin, which was originally identified as a presenilin interacting protein, has since been shown to be involved in the processing of presenilin(s), the modulation of amyloid beta-peptide (Abeta) levels and apoptosis. Subsequent to its original identification, calsenilin was shown to act as a downstream regulatory element antagonist modulator (and termed DREAM), as well as to interact with and modulate A-type potassium channels (and termed KChIP3). Calsenilin is primarily a cytoplasmic protein that must translocate to the nucleus to perform its function as a transcriptional repressor. This study was designed to determine the cellular events that modulate the translocation of calsenilin from the cytoplasm to the nucleus. The nuclear translocation of calsenilin was found to be enhanced following serum deprivation. A similar effect was observed when cells were treated with pharmacological agents that directly manipulate the levels of intracellular calcium (caffeine and the calcium ionophore A23187), suggesting that the increased levels of calsenilin in the nucleus are mediated by changes in intracellular calcium. A calsenilin mutant that was incapable of binding calcium retained the ability to translocate to the nucleus. Taken together, these findings indicate that the level of intracellular calcium can modulate the nuclear translocation of calsenilin and that this process does not involve the direct binding of calcium to calsenilin. PMID:15086516

Zaidi, Nikhat F; Thomson, Emma E; Choi, Eun-Kyoung; Buxbaum, Joseph D; Wasco, Wilma

2004-05-01

281

Translocation and Endocytosis for Cell-penetrating Peptide Internalization  

PubMed Central

Cell-penetrating peptides (CPPs) share the property of cellular internalization. The question of how these peptides reach the cytoplasm of cells is still widely debated. Herein, we have used a mass spectrometry-based method that enables quantification of internalized and membrane-bound peptides. Internalization of the most used CPP was studied at 37 °C (endocytosis and translocation) and 4 °C (translocation) in wild type and proteoglycan-deficient Chinese hamster ovary cells. Both translocation and endocytosis are internalization pathways used by CPP. The choice of one pathway versus the other depends on the peptide sequence (not the number of positive changes), the extracellular peptide concentration, and the membrane components. There is no relationship between the high affinity of these peptides for the cell membrane and their internalization efficacy. Translocation occurs at low extracellular peptide concentration, whereas endocytosis, a saturable and cooperative phenomenon, is activated at higher concentrations. Translocation operates in a narrow time window, which implies a specific lipid/peptide co-import in cells.

Jiao, Chen-Yu; Delaroche, Diane; Burlina, Fabienne; Alves, Isabel D.; Chassaing, Gerard; Sagan, Sandrine

2009-01-01

282

Enzyme-modulated DNA Translocation through a Nanopore  

PubMed Central

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.

Panwar, Ajay S.; Muthukumar, M.

2009-01-01

283

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

284

Influence of polymer-pore interaction on the translocation of a polymer through a nanopore  

NASA Astrophysics Data System (ADS)

The translocation of a bond fluctuation polymer through an interacting nanopore is studied using dynamic Monte Carlo simulation. A driving force F is applied only for monomers inside the pore. The influence of polymer-pore interaction on the scaling relation ?˜N? is studied for both unbiased and biased translocations, with ? the translocation time and N the polymer length. Results show that the exponent ? is dependent on the polymer-pore interaction. For a noninteracting pore, we find ?=2.48 for unbiased translocation and ?=1.35 for strong biased translocation; for strong attraction, we find ?=2.35 for unbiased translocation and ?=1.22 for strong biased translocation. The unbiased translocation corresponds to the low-NF regime whereas the strong biased translocation corresponds to the high-NF regime.

Luo, Meng-Bo; Cao, Wei-Ping

2012-09-01

285

Timing of Canopy Closure Influences Carbon Translocation and Seed Production of an Understorey Herb, Trillium apetalon (Trilliaceae)  

PubMed Central

Background and Aims The light availability on a temperate, deciduous-forest floor varies greatly, reflecting the seasonal leaf dynamics of the canopy trees. The growth and/or reproductive activity of understorey plants should be influenced by the length of the high-irradiance period from snowmelt to canopy closure. The aim of the present study was to clarify how spring-blooming species regulate the translocation of photosynthetic products to current reproduction and storage organs during a growing season in accordance with the changing light conditions. Methods Growth pattern, net photosynthetic rate, seed production, and shoot and flower production in the next year of Trillium apetalon were compared between natural and experimentally shaded conditions. Furthermore, translocation of current photosynthetic products within plants was assessed by a labelled carbon-chase experiment. Key Results During the high-irradiance period, plants showed high photosynthetic ability, in which current products were initially used for shoot growth, then reserved in the rhizome. Carbon translocation to developing fruit occurred after canopy closure, but this was very small due to low photosynthetic rates under the darker conditions. The shading treatment in the early season advanced the time of carbon translocation to fruit, but reduced seed production in the current year and flower production of the next year. Conclusions Carbon translocation to the storage organ had priority over seed production under high-irradiance conditions. A shortened bright period due to early canopy closure effectively restricts carbon assimilation, which greatly reduces subsequent reproductive output owing to low photosynthetic products for fruit development and small carbon storage for future reproduction. As populations of this species are maintained by seedling recruitment, acceleration of canopy closure timing may influence the maintenance and dynamics of populations.

Ida, Takashi Y.; Kudo, Gaku

2008-01-01

286

Textured backgrounds alter perceived speed.  

PubMed

Both the luminance contrast of an object, and the nature of the background texture over which it moves, are known to influence its perceived speed. In this study the effect of object contrast upon perceived speed was investigated for targets moving across textured patterns of various contrasts. Experiment 1 showed a strong effect of contrast for objects moving over homogenous backgrounds, that was reduced or abolished if the object moved over a textured background. A further experiment suggested that this reduction may be the result of an increase in target visibility, perhaps as a result of additional 'second order' motion signals produced by motion over texture backgrounds. A final experiment suggested that two processes were occurring: (1) higher contrast backgrounds appeared to increase the perceived speeds of all objects; and (2) that higher contrast backgrounds eliminated the contrast induced changes in perceived speed. PMID:10824266

Blakemore, M R; Snowden, R J

2000-01-01

287

Uptake and translocation of hexachlorobenzene: Oilpumpkin and sunflower  

SciTech Connect

The uptake of hexachlorobenzene (HCB) and its translocation to seeds were studied with oil pumpkin and sunflower plants. Open air pot experiments were conducted with soil treated with different amounts of HCB. 14C-labelled HCB was used in solution culture experiments with young plants to investigate the distribution of HCB within the plants. During the experiments the contaminant was taken up by the root system of pumkin plant and translocated intensity to the reproductive organs. Autoradiographic pictures of crossections of stems and young fruits confirm this. Such translocation mechanism was not found in sunflower. Nevertheless it can be assumed that under field conditions the uptake of vaporized HCB from contamination soil by foliage and fruits of oil pumpkin is the main pathway of contamination.

NONE

1993-10-01

288

Resistance to glyphosate from altered herbicide translocation patterns.  

PubMed

Glyphosate-resistant weeds have evolved as a result of the intensive use of glyphosate for weed control. An alteration in the way glyphosate is translocated within the plant has been identified as a mechanism of glyphosate resistance in populations of Lolium rigidum Gaud., L. multiflorum Lam. and Conyza canadensis (L.) Cronq. In these resistant plants, glyphosate becomes concentrated in the leaves rather than being translocating throughout the plant. This type of resistance is inherited as a single dominant or semi-dominant allele. Resistance due to reduced translocation appears to be a common mechanism of resistance in L. rigidum and C. canadensis, probably because it provides a greater level of resistance than other mechanisms. This type of glyphosate resistance also appears to reduce the fitness of plants that carry it. This may influence how glyphosate resistance can be managed. PMID:18080284

Preston, Christopher; Wakelin, Angela M

2008-04-01

289

Eld's deer translocated to human-inhabited areas become nocturnal.  

PubMed

As human populations expand and nonhuman animals decline, understanding the interactions between people and wildlife is essential. For endangered species, appreciating the effect of human disturbance can be important for their conservation. However, a human disturbance angle is often absent from ecological research, despite growing evidence of the negative impact of nonfatal human interference. Here, we monitored Hainan Eld's deer living within a reserve and translocated animals living amongst villagers. We show that translocated deer deviated from a crepuscular activity pattern and became increas-. ingly nocturnal, and most active when villagers were not. It appears that translocated deer adapted over time to human disturbance and this pattern is similar to that of other species during periods of hunting. People do not pose an actual threat to Eld's deer, but their presence triggered a response akin to predator avoidance and may be interfering with broader aspects of their biology and conservation. PMID:21404824

Pan, Duo; Teng, Liwei; Cui, Fangjie; Zeng, Zhigao; Bravery, Benjamin D; Zhang, Qiong; Song, Yanling

2011-02-01

290

Crystallographic snapshot of cellulose synthesis and membrane translocation.  

PubMed

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 membrane-integrated 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-BcsB 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. PMID:23222542

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

2012-12-09

291

A translocated mitochondrial cytochrome b pseudogene in voles (Rodentia: Microtus)  

PubMed

A full-length cytochrome b pseudogene was found in rodents; it has apparently been translocated from a mitochondrion to the nuclear genome in the subfamily Arvicolinae. The pseudogene (psi cytb) differed from its mitochondrial counterpart at 201 of 1143 sites (17.6%) and by four indels. Cumulative evidence suggests that the pseudogene has been translocated to the nucleus. Phylogenetic reconstruction indicates that the pseudogene arose before the diversification of M. arvalis/M. rossiaemeridionalis from M. oeconomus, but after the divergence of the peromyscine/sigmodontine/ arvicoline clades some approximately 10 MYA. Published rates of divergence between mitochondrial genes and their nuclear pseudogenes suggest that the translocation of this mitochondrial gene to the nuclear genome occurred some 6 MYA, in agreement with the phylogenetic evidence. PMID:10093228

DeWoody, J A; Chesser, R K; Baker, R J

1999-03-01

292

Evaluating Translocation Gene Fusions by SNP Array Data  

PubMed Central

Somatic cell genetic alterations are a hallmark of tumor development and progression. Although various technologies have been developed and utilized to identify genetic aberrations, identifying genetic translocations at the chromosomal level is still a challenging task. High density SNP microarrays are useful to measure DNA copy number variation (CNV) across the genome. Utilizing SNP array data of cancer cell lines and patient samples, we evaluated the CNV and copy number breakpoints for several known fusion genes implicated in tumorigenesis. This analysis demonstrated the potential utility of SNP array data for the prediction of genetic aberrations via translocations based on identifying copy number breakpoints within the target genes. Genome-wide analysis was also performed to identify genes harboring copy number breakpoints across 820 cancer cell lines. Candidate oncogenes were identified that are linked to potential translocations in specific cancer cell lines.

Liu, Hong; Zilberstein, Asher; Pannier, Pascal; Fleche, Frederic; Arendt, Christopher; Lengauer, Christoph; Hahn, Chang S.

2012-01-01

293

Dynamics of polymer translocation into a circular nanocontainer through a nanopore  

NASA Astrophysics Data System (ADS)

Using Langevin dynamics simulations, we investigate the dynamics of polymer translocation into a circular nanocontainer through a nanopore under a driving force F. We observe that the translocation probability initially increases and then saturates with increasing F, independent of ?, which is the average density of the whole chain in the nanocontainer. The translocation time distribution undergoes a transition from a Gaussian distribution to an asymmetric distribution with increasing ?. Moreover, we find a nonuniversal scaling exponent of the translocation time as chain length, depending on ? and F. These results are interpreted by the conformation of the translocated chain in the nanocontainer and the time of an individual segment passing through the pore during translocation.

Zhang, Kehong; Luo, Kaifu

2012-05-01

294

Finnish Disease Heritage I: characteristics, causes, background.  

PubMed

This review of the Finnish Disease Heritage (FDH), a group of rare hereditary diseases that are overrepresented in Finland, includes the following topics: FDH characteristics, causes and background, primary theory, revis(it)ed theory, consanguineous marriages in Finland, internal migration of the 1500s, family series for further FDH studies, geography and population structure as a basis for FDH, geography of individual diseases, the structure of FDH families, family structure in individual diseases, Finnish gene mutations, linkage disequilibrium and haplotypes, age of gene mutations, frequencies of disease genes and carriers, and a short description of the possible future of FDH. PMID:12627295

Norio, Reijo

2003-03-08

295

Stochastic background from inspiralling double neutron stars  

SciTech Connect

We review the contribution of extra galactic inspiralling double neutron stars, to the LISA astrophysical gravitational wave foreground. Using recent fits of the star formation rate, we show that sources beyond z{sub *}=0.005 contribute to a truly continuous background, which may dominate the LISA instrumental noise in the range 3{approx_equal}10{sup -4}-1x10{sup -2} Hz and overwhelm the galactic WD-WD confusion noise at frequencies larger than {nu}{sub o}{approx_equal}2x10{sup -3}.

Regimbau, Tania [Dpt. ARTEMIS, Observatoire de la Cote d'Azur, BP 429 06304 Nice (France)

2007-02-15

296

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

297

Voltage-Driven DNA Translocations through a Nanopore  

NASA Astrophysics Data System (ADS)

We measure current blockade and time distributions for single-stranded DNA polymers during voltage-driven translocations through a single ?-hemolysin pore. We use these data to determine the velocity of the polymers in the pore. Our measurements imply that, while polymers longer than the pore are translocated at a constant speed, the velocity of shorter polymers increases with decreasing length. This velocity is nonlinear with the applied field. Based on this data, we estimate the effective diffusion coefficient and the energy penalty for extending a molecule into the pore.

Meller, Amit; Nivon, Lucas; Branton, Daniel

2001-04-01

298

First Pregnancies After Preconception Diagnosis of Translocations of Maternal Origin  

Microsoft Academic Search

Objective: To develop an approach to preimplantation diagnosis of translocations that would not require the use of specific DNA probes for each translocation type.Design: Retrospective analysis.Setting: Clinic.Patient(s): Two patients with 45XX,der(13;14)(q10;q10) karyotypes and one patient with a 46XX,t(4;14)(p15;q24) karyotype.Intervention(s): Based on the observation that first polar body chromosomes remain at the metaphase stage for a few hours after oocyte retrieval,

Santiago Munné; Richard Scott; David Sable; Jacques Cohen

1998-01-01

299

Lattice QCD in Background Fields  

SciTech Connect

Electromagnetic properties of hadrons can be computed by lattice simulations of QCD in background fields. We demonstrate new techniques for the investigation of charged hadron properties in electric fields. Our current calculations employ large electric fields, motivating us to analyze chiral dynamics in strong QED backgrounds, and subsequently uncover surprising non-perturbative effects present at finite volume.

William Detmold, Brian Tiburzi, Andre Walker-Loud

2009-06-01

300

Background adaptive multispectral band selection  

Microsoft Academic Search

AN initial automated band selection algorithm suitable for real-time application with tunable multispectral cameras is presented for multispectral target detection. The method and algorithm were developed from analyses of several background and target signatures collected from a field test using the prototype Tunable Filter Multispectral Camera (TFMC). Target and background data from TFMC imagery were analyzed to determine the detection

Frank J. Crosby; John H. Holloway; V. Todd Holmes; Arthur C. Kenton

2001-01-01

301

Background Television and Reading Performance.  

ERIC Educational Resources Information Center

|Tests G. Armstrong's and B. Greenberg's model of the effect of background television on cognitive performance, applied to reading comprehension and memory. Finds significant deleterious effects of background television, stronger and more consistent effects when testing immediately after reading, and more consistently negative effects resulting…

Armstrong, G. Blake; And Others

1991-01-01

302

Background estimation in experimental spectra  

SciTech Connect

A general probabilistic technique for estimating background contributions to measured spectra is presented. A Bayesian model is used to capture the defining characteristics of the problem, namely, that the background is smoother than the signal. The signal is allowed to have positive and/or negative components. The background is represented in terms of a cubic spline basis. A variable degree of smoothness of the background is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity and allows uncertainties in the background to be estimated. Our technique is demonstrated on a particle induced x-ray emission spectrum from a geological sample and an Auger spectrum from iron, which contains signals with both positive and negative components. (c) 2000 The American Physical Society.

Fischer, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association D-85740 Garching bei Muenchen, (Germany); Hanson, K. M. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association D-85740 Garching bei Muenchen, (Germany); Los Alamos National Laboratory, MS P940, Los Alamos, New Mexico 87545 (United States); Dose, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association D-85740 Garching bei Muenchen (Germany); Linden, W. von der [Institut fuer Theoretische Physik, Technische Universitaet Graz, Petersgasse 16, A-8010 Graz, (Austria)

2000-02-01

303

Geochemical background - an environmental perspective  

NASA Astrophysics Data System (ADS)

This article presents the concept of geochemical background from an environmental perspective. The idea of establishing the typical concentrations of elements in various environmental compartments, proposed by exploratory geochemists almost 50 years ago was important for the detection of anomalous element concentrations, thus providing a basic tool in the search for new mineral deposits. At present, the knowledge of the geochemical background of hazardous elements is essential for: defining pollution, identifying the source of contamination, and for establishing reliable environmental quality criteria for soils, sediments and surface waters. The article presents geochemical methods of evaluation of anthropogenic influence on the environment and discusses the problem of defining and understanding the term "geochemical background" and related terms in environmental sciences. It also briefly presents methods of geochemical background evaluation based on the results of environmental sample analyses. It stresses the role of geochemical background in our understanding of environmental pollution and pollution prevention.

Ga?uszka, Agnieszka; Migaszewski, Zdzis?aw M.

2011-01-01

304

The SWI/SNF protein ATRX co-regulates pseudoautosomal genes that have translocated to autosomes in the mouse genome  

PubMed Central

Background Pseudoautosomal regions (PAR1 and PAR2) in eutherians retain homologous regions between the X and Y chromosomes that play a critical role in the obligatory X-Y crossover during male meiosis. Genes that reside in the PAR1 are exceptional in that they are rich in repetitive sequences and undergo a very high rate of recombination. Remarkably, murine PAR1 homologs have translocated to various autosomes, reflecting the complex recombination history during the evolution of the mammalian X chromosome. Results We now report that the SNF2-type chromatin remodeling protein ATRX controls the expression of eutherian ancestral PAR1 genes that have translocated to autosomes in the mouse. In addition, we have identified two potentially novel mouse PAR1 orthologs. Conclusion We propose that the ancestral PAR1 genes share a common epigenetic environment that allows ATRX to control their expression.

Levy, Michael A; Fernandes, Andrew D; Tremblay, Deanna C; Seah, Claudia; Berube, Nathalie G

2008-01-01

305

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

306

Earth and Atmosphere Shine Backgrounds.  

National Technical Information Service (NTIS)

The report reviews current knowledge of earth and atmosphere shine background radiation. Field measurements accomplished up to 1968 are summarized with references, quoted measurement data and effective spectral radiance values. The relation of the several...

A. J. Grobecker

1968-01-01

307

BACKGROUND INFORMATION FOR THE PEDIATRIC ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Meeting Background Materials Blinatumomab (AMG 103) Page 1 AVAILABLE FOR PUBLIC DISCLOSURE WITHOUT REDACTION ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

308

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

309

Low background techniques in XMASS  

SciTech Connect

The XMASS project aims to detect pp and {sup 7}Be solar neutrinos, neutrino-less double beta decay, and dark matter searches using ultra-pure liquid xenon. The first stage of XMASS project is concentrated on dark matter searches using 800 kg liquid xenon detector which requires low background and low threshold. Several techniques applied to XMASS detector for low background will be presented.

Takeda, Atsushi [Kamioka Observatory, ICRR, University of Tokyo, 456 Higashi-Mozumi, Kamioka-cho, Hida, Gifu, 506-1205 (Japan)

2011-04-27

310

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

311

Perfluorocarbon background concentrations in Europe  

Microsoft Academic Search

Five studies of the background level of several perfluorocarbon compounds in Europe are here presented together with measurements from the European Tracer Experiment (ETEX). The tracers used during the two ETEX tracer releases were the perfluorocarbons (PFCs); perfluoromethylcyclohexane (C7F14, PMCH) and perfluoromethylcyclopentane (C6F12, PMCP). Their background concentrations were detected by using both passive and active sampling techniques, to define the

Anne Grete Straume; Russel N. Dietz; Katrin Nodop

1998-01-01

312

Force-Driven Translocation of a Polymer through a Nanopore  

NASA Astrophysics Data System (ADS)

We study the far from equilibrium translocation of a DNA molecule through a nanopore. The pore is much narrower than the DNA, so the electrically driven DNA undergoes dramatic deformations during its passage. Using an idealized model in which the DNA is assumed to be a very long and flexible homopolymer driven by a force exerted only in the pore, we modify a previously developed method by introducing the concept of ``iso-flux trumpet''. We show that although the speed of the process is determined by the friction of the trailing part with the solvent, friction dissipates a small portion of the work performed by the electric field on the polymer, and the work is mostly dissipated by the irreversible stretching and destretching of the polymer squeezed into the small pore. Moreover, due to such stretches essentially caused by the membrane, a net heat transfer occurs during translocation from the post-translocation to the pre-translocation side of the membrane. The current theory can be improved by accounting for the nonzero field outside the pore and by considering the coupling between electric and hydrodynamic fields. The forces exerted by such fields on the DNA bulk not only alter the passage dynamics, but also introduce deformations on the initial conformation of the polymer.

Rowghanian, Payam; Grosberg, Alexander

2012-02-01

313

Peptide translocators with engineered dehydration-prone hydrogen bonds  

NASA Astrophysics Data System (ADS)

The unfavorable crossing of cell membranes by water-soluble peptides poses a challenge to peptide-based drug delivery. Thus the authors engineered a conformational switch that modulates cellular translocation. The peptide design hinges on dehydration propensities of hydrogen bonds that form to mitigate polar-group internalization penalties and is experimentally corroborated through cell-internalization assays.

Maddipati, Sridhar; Fernández, Ariel

2007-02-01

314

Female Pressure: A translocal feminist youth-oriented cultural network  

Microsoft Academic Search

This article explores the potentials and limitations of Female Pressure, a collective of female DJs, music producers and club organizers that makes use of mailing lists, social networking platforms and a database to form a translocal feminist network. The article's empirical sections are based on the analysis of the two Female Pressure mailing lists, complemented by the analysis of the

Rosa Reitsamer

2012-01-01

315

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

316

Dynamics of growth, carbon and nutrient translocation in Zizania latifolia  

Microsoft Academic Search

We studied the seasonal resource dynamics between organs of wild rice (Zizania latifolia (Griseb.) Turcz. ex Stapf.) to obtain a better understanding of its growth dynamics, carbon and nutrient translocation. The results of observation from January 2002 to February 2004 showed the shoot density markedly increased after emergence of shoots at the end of March until May (up to 800ind\\/m2).

Takashi Asaeda; Kian Siong

2008-01-01

317

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

318

Protein translocation into and across the chloroplastic envelope membranes  

Microsoft Academic Search

Post-translational protein import into chloroplasts follows a common route characterised by the need for nucleoside-triphosphates at various steps and two distinct protein import machineries at the outer and inner envelope membrane, respectively. Several subunits of these complexes have been elucidated. In contrast, protein translocation into the chloroplastic outer envelope uses distinct and various but poorly characterised insertion pathways. A topological

J. Soll; R. Tien

1998-01-01

319

Acrocentric p-arm satellite III DNA and Robertsonian Translocations  

SciTech Connect

Although all of the acrocentric chromosomes (13, 14, 15, 21 and 22) have been observed to undergo Robertsonian Translocation, the most frequent exchanges are between chromosomes 13 and 14, and between 14 and 21, with the translocation breakpoint demonstrated to occur in the proximal short arm region. It is thought that common sequences on different subsets of non-homologous acrocentric chromosomes may allow particular pairs of chromosomes to interact more frequently and predispose the chromosomes to Robertsonian Translocations. We have indentified ten new human acrocentric p-arm satellite III DNA sequences, with the following interchromosomal distribution: (1) five sequences on all the acrocentric chromosomes; (2) two sequences on chromosomes 13, 14 and 21; (3) two sequences on chromosomes 14 and 22; (4) one sequence on chromosomes 13 and 21. This provides the first evidence of complex sharing of sequences on the short arm of these chromosomes. Identical distribution profiles as observed for groups 2, 3 and 4 have also been seen in the centromeric alpha-satellite DNA of these chromosomes, suggesting the concerted evolution of two different types of DNA on the short arm and the centromeric regions of the acrocentric chromosomes. Of particular interest are the group 2 sequences which we postulate to be responsible for the t(13q14q) and t(14q21q) translocation events.

Choo, K.H.A.; McQuillan, C.; Trowell, H.E. [Murdoch Institute for Research into Birth Defects, Victoria (Australia)] [and others

1994-09-01

320

Clinical manifestations of familial 13;18 translocation.  

PubMed Central

Female first cousins, aged 21 and 2 1/2 years, with many of the characteristic features of trisomy 18, were found to have identical unbalanced translocations, 46,XX,--13, + der(13)t(13;18) (p13;q12)mat. Clinical features of another cousin, two uncles, and an aunt suggested that they, too, had a partial trisomy 18 phenotype. The long survival and normal menstrual and secondary sexual development in one case are remarkable. A heritable balanced translocation, 46,XX or XY, t(13;18) (p13;q12), was detected in the mothers of the cases, a sib, an aunt, and two uncles. Translocation carriers had abnormalities in gonadal structure or function, with aspermia in males and polycystic ovaries with infertility in several females, suggesting that some gene controlling reproductive development occurs on the long arm of chromosome 18, with normal function interrupted at the breakpoint. Balanced translocation carriers may also be at greater risk for both benign and malignant neoplasms, which included acute leukaemia in an uncle and adenocarcinoma of the stomach at an early age in the grandmother. Although aetiological laboratory studies identified no premalignant state, the clinical findings suggest a defect that may predispose to cytogenetic abnormalities and malignancy. Images

Blattner, W A; Kistenmacher, M L; Tsai, S; Punnett, H H; Giblett, E R

1980-01-01

321

The protective role of gastric acidity in neonatal bacterial translocation  

Microsoft Academic Search

The acid environment of the stomach serves as an important defense against intestinal colonization by potentially pathogenic bacteria. The purpose of this study was to examine the effect of increased gastric pH on bacterial translocation in a neonatal rabbit model. Fifty-nine rabbit pups were delivered by cesarean section and randomly divided into normal acid (NA) and reduced acid (RA) groups.

John E Dinsmore; Richard J Jackson; Samuel D Smith

1997-01-01

322

Functional nanoparticles translocation into cell and adhesion force curve analysis.  

PubMed

The aim of this research is to investigate the cell translocation of two functional nanoparticles (barium sulfate (BaSO4NPs), europium (III) doped gadolinium oxide nanoparticles (Gd2O3@EuNPs)) into A549 cells by Bio-Atomic Force Microscopy (Bio-AFM). Successful cell translocation of these two nanoparticles are ensured from the measurement of changes in the cell surface roughness and interaction (extension), retraction forces from the vertical deflection of tip towards substrate surfaces through force-distance curve slope analysis. Measurement of typical adhesion forces (i.e., extension and retraction) between the tip-substrate (0.0963 and 1.155 nN), tip-A549 cell substrate (0.1177 and 2.468 nN), tip-Gd2O3@EuNPs/A549 substrate (0.0785 and 0.4276 nN) and tip-BaSO4NPs/A549 substrate (0.518 and 6.838 nN) confirms the successful cell translocation of functional nanoparticles into A549 cells. Further the nanoscale resolution of topographical height and 3D images evinces the surface characteristics of normal A549 cells and nanoparticles translocated A549 cells. PMID:23421137

Lee, Haisung; Veerapandian, Murugan; Kim, Byung Tae; Yun, Kyusik; Seo, Soo-Won

2012-10-01

323

Driven DNA translocation through thin and long nanopores  

NASA Astrophysics Data System (ADS)

We utilize Brownian dynamics simulation to study polymer translocation through a nanopore driven by an electric field using a coarse-grained bead-spring model for the translocating DNA. We study mean translocation time as a function of the chain length N, the width w of the pore, and external bias F. Unlike many previous studies, we critically examine the scaling of as a function of the ratio N/w and F. For a thin pore, our preliminary results indicate that the mean translocation time ˜N^2?, where ? is the Flory exponent, although the slope shows a weak but non-negligible dependence on the external bias F for the chain lengths considered so far. Our simulation results are consistent with experiments done in solid-state nanopore^*,+.^*Work done in collaboration with Heath Morrison, Prof. Kurt Binder and Prof. Andrey Milchev.^+ A. J. Storm, C. Storm, J. Chen, H. Zandbergen, J-F Joanny, C. Dekker, Nano Letters, 5, 1193 (2005).

Bhattacharya, Aniket; Morrison, William H.

2006-03-01

324

Dephosphorylation by calcineurin regulates translocation of Drp1 to mitochondria  

Microsoft Academic Search

Changes in mitochondrial morphology that occur during cell cycle, differentiation, and death are tightly regulated by the balance between fusion and fission processes. Excessive fragmentation can be caused by inhibition of the fusion machinery and is a common consequence of dysfunction of the organelle. Here, we show a role for calcineurin-dependent translocation of the profission dynamin related protein 1 (Drp1)

G. M. Cereghetti; A. Stangherlin; O. Martins de Brito; C. R. Chang; C. Blackstone; P. Bernardi; L. Scorrano

2008-01-01

325

Endotoxin in the gut and chylomicrons: translocation or transportation?  

Microsoft Academic Search

The intestine contains trillions of microorganisms and massive amounts of endotoxin, which if absorbed from the intestinal lumen into the body would result in over- whelming septic shock and death. Recently there has been an increasing appreciation of the role of gut microorganisms and their translocation into the systemic circulation in pro- moting metabolic disorders including obesity and insulin resistance,

Carl Grunfeld; Kenneth R. Feingold

2008-01-01

326

Transcription factors and translocations in lymphoid and myeloid leukemia  

Microsoft Academic Search

Chromosomal translocations involving transcription factors and aberrant expression of transcription factors are frequently associated with leukemogenesis. Transcription factors are essential in maintaining the regulation of cell growth, development, and differentiation in the hematopoietic system. Alterations in the mechanisms that normally control these functions can lead to hematological malignancies. Further characterization of the molecular biology of leukemia will enhance our ability

HN Crans; KM Sakamoto

2001-01-01

327

Spontaneous Abortions Are Reduced After Preconception Diagnosis of Translocations  

Microsoft Academic Search

Purpose:Preimplantation genetic diagnosis of translocations has seldom been attempted. Recently, a genetic test based on analyzing polar bodies at the methaphase stage, following fluorescent in situ hybridization with commercially available whole-chromosome painting DNA probes has been presented. Here we report the use of this method in seven couples in whom the female was a carrier of one of these balanced

Santiago Munné; Larry Morrison; Jingly Fung; Carmen Márquez; Ulli Weier; Muhterem Bahçe; David Sable; Larry Grundfeld; Bill Schoolcraft; Richard Scott; Jacques Cohen

1998-01-01

328

Campylobacter fetus translocation across Caco-2 cell monolayers  

Microsoft Academic Search

Campylobacter fetus is a recognized pathogen of cattle and sheep, though human infection has also been reported. Ingestion of contaminated food or water is a proposed route of transmission for both humans and animals. The subsequent detection of the organism from extra-intestinal and systemic locations implies an ability to translocate across epithelial barriers. To determine how C. fetus disseminates from

N. T. Baker; L. L. Graham

2010-01-01

329

SEX CHROMOSOME TRANSLOCATIONS IN THE EVOLUTION OF REPRODUCTIVE ISOLATION  

Microsoft Academic Search

Haldane's rule states that in organisms with differentiated sex chromo- somes, hybrid sterility or inviability is generally expressed more frequently in the heterogametic sex. This observation has been variously explained as due to either genic or chromosomal imbalance. The fixation probabilities and mean times to fixation of sex-chromosome translocations of the type necessary to explain Haldane's rule on the basis

MARTIN L. TRACEY

1972-01-01

330

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

331

Scaling exponents of forced polymer translocation through a nanopore.  

PubMed

We investigate several properties of a translocating homopolymer through a thin pore driven by an external field present inside the pore only using Langevin Dynamics (LD) simulations in three dimensions (3D). Motivated by several recent theoretical and numerical studies that are apparently at odds with each other, we estimate the exponents describing the scaling with chain length (N) of the average translocation time , the average velocity of the center of mass , and the effective radius of gyration during the translocation process defined as approximately Nalpha, approximately N(-delta), and Rg approximately Nnu respectively, and the exponent of the translocation coordinate (s-coordinate) as a function of the translocation time approximately tbeta. We find alpha = 1.36 +/- 0.01, beta = 1.60+/- 0.01 for approximately taubeta and beta = 1.44 +/- 0.02 for approximately taubeta, delta = 0.81 +/- 0.04, and nu congruent with nu = 0.59 +/- 0.01, where nu is the equilibrium Flory exponent in 3D. Therefore, we find that approximately N1.36 is consistent with the estimate of approximately /. However, as observed previously in Monte Carlo (MC) calculations by Kantor and Kardar (Y. Kantor, M. Kardar, Phys. Rev. E 69, 021806 (2004)) we also find the exponent alpha = 1.36 +/- 0.01 < 1 + nu. Further, we find that the parallel and perpendicular components of the gyration radii, where one considers the "cis" and "trans" parts of the chain separately, exhibit distinct out-of-equilibrium effects. We also discuss the dependence of the effective exponents on the pore geometry for the range of N studied here. PMID:19669181

Bhattacharya, A; Morrison, W H; Luo, K; Ala-Nissila, T; Ying, S-C; Milchev, A; Binder, K

2009-08-08

332

Scaling exponents of forced polymer translocation through a nanopore  

NASA Astrophysics Data System (ADS)

We investigate several properties of a translocating homopolymer through a thin pore driven by an external field present inside the pore only using Langevin Dynamics (LD) simulations in three dimensions (3D). Motivated by several recent theoretical and numerical studies that are apparently at odds with each other, we estimate the exponents describing the scaling with chain length (Nof the average translocation time ensuremath , the average velocity of the center of mass ensuremath < vCM> , and the effective radius of gyration ensuremath < {R}_g> during the translocation process defined as ensuremath ˜ N? , ensuremath < vCM > ˜ N-? , and ensuremath {R}g ˜ Nbar?} respectively, and the exponent of the translocation coordinate (s -coordinate) as a function of the translocation time ensuremath < s^2(t)>˜ t? . We find ensuremath ?=1.36 ± 0.01 , ensuremath ?=1.60 ± 0.01 for ensuremath < s^2(t)>˜ ?? and ensuremath bar{?=1.44 ± 0.02 for ensuremath ˜?bar?} , ensuremath ?=0.81 ± 0.04 , and ensuremath bar{???=0.59 ± 0.01 , where ? is the equilibrium Flory exponent in 3D. Therefore, we find that ensuremath ˜ N1.36 is consistent with the estimate of ensuremath ˜< Rg >/< vCM > . However, as observed previously in Monte Carlo (MC) calculations by Kantor and Kardar (Y. Kantor, M. Kardar, Phys. Rev. E 69, 021806 (2004)) we also find the exponent ? = 1.36 ± 0.01 < 1 + ?. Further, we find that the parallel and perpendicular components of the gyration radii, where one considers the “cis” and “trans” parts of the chain separately, exhibit distinct out-of-equilibrium effects. We also discuss the dependence of the effective exponents on the pore geometry for the range of N studied here. in here

Bhattacharya, A.; Morrison, W. H.; Luo, K.; Ala-Nissila, T.; Ying, S.-C.; Milchev, A.; Binder, K.

2009-08-01

333

Bid is not required for Bax translocation during UV-induced apoptosis  

Microsoft Academic Search

UV irradiation triggers apoptosis through both the membrane death receptor and the intrinsic apoptotic signaling pathways. Bax, a member of the Bcl-2 family of proteins, translocates from the cytosol to the mitochondrial membrane during UV-induced apoptosis, but the regulation of Bax translocation by UV irradiation remains elusive. In this study, we show that Bax translocation, caspase-3 activation and cell death

Yinyuan Wu; Da Xing; Wei R. Chen; Xichao Wang

2007-01-01

334

Fish Pathogen Screening and Its Influence on the Likelihood of Accidental Pathogen Introduction during Fish Translocations  

Microsoft Academic Search

Fish translocations are an important tool in fisheries management, yet translocating fish carries the risk of introducing unwanted pathogens. Although pathogen screening can be a useful tool for managing the risk associated with fish translocations, screening cannot eliminate this risk. This paper addresses these problems by demonstrating that two elements must be considered when designing efficient and effective aquatic pathogen

Eli P. Fenichel; Jean I. Tsao; Michael Jones; Graham J. Hickling

2008-01-01

335

Partial trisomy 7p associated with familial 7p;22q translocation  

Microsoft Academic Search

A newly described partial trisomy of the short arm of chromosome number 7 is reported in a familial translocation between 7 and 22. The unbalanced translocation was found in one family member, the propositus, and the balanced form in 5 other members. The possibility of this translocation being a rare telomeric attachment previously undescribed in humans is discussed. Prominent clinical

L M Larson; W A Wasdahl; S M Jalal

1977-01-01

336

The feeding ecology of translocated howler monkeys, {\\\\it Alouatta pigra\\\\\\/}, in Belize  

Microsoft Academic Search

The feeding ecology of translocated black howler monkeys (Alouatta pigra) was studied in Belize, Central America. Data collection began in March 1994, in the Community Baboon Sanctuary (CBS), in northern Belize. In May 1994, two troops were translocated to the Cockscomb Basin Wildlife Sanctuary (CBWS), in southern Belize and studied for 12 months. Two troops translocated previously into CBWS and

Scott Charles Silver

1998-01-01

337

GENETIC LINKAGE IN SOYBEAN: CLASSICAL GENETIC LINKAGE GROUPS 6 AND 8, AND TRANSLOCATION BREAKPOINTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Reciprocal chromosome translocations are important for locating genes to linkage groups (LGs). Identifying the chromosomes involved in translocations is necessary for the isolation of tester sets. Our objectives were 1) to determine the location of translocation breakpoints by testing linkage with l...

338

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

339

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

340

Cre Reporter System To Monitor the Translocation of Type III Secreted Proteins into Host Cells  

Microsoft Academic Search

Central to the study of type III secretion systems is the availability of reporter systems to monitor bacterial protein translocation into host cells. We report here the development of a bacteriophage P1 Cre recombinase-based system to monitor the translocation of bacterial proteins into mammalian cells. Bacteriophage P1 Cre recombinase fused to the secretion and translocation signals of Salmonella enterica serovar

Gabriel Briones; Dirk Hofreuter; Jorge E. Galan

2006-01-01

341

Cigarette smoking during pregnancy: chromosome translocations and phenotypic susceptibility in mothers and newborns  

PubMed Central

The effects of maternal cigarette smoking during pregnancy on structural chromosome aberrations were evaluated in peripheral lymphocytes from 239 mothers and their 241 newborns to determine whether smoking during pregnancy, genetic susceptibility, and race are associated with chromosome aberrations including translocations. Demographic information and cigarette smoking data were obtained via questionnaire. There were 119 Caucasian Americans, 118 African Americans, and 2 Asian Americans. The average maternal age was 24.9 ± 5.8 (mean ± S.D.) years. Thirty-nine percent of the Caucasian Americans and 45.4% of the African Americans self-reported that they were active smokers during the index pregnancy. The average number of cigarettes smoked per day was 2.65 ± 5.75 and 1.37 ± 3.17 for Caucasian and African American mothers, respectively. Peripheral blood lymphocytes from the mother and from the fetal side of the placenta were evaluated for chromosome aberrations by whole chromosome painting and for genetic susceptibility using an in vitro bleomycin challenge assay. Spontaneous translocation frequencies in both maternal and newborn lymphocytes were not associated with cigarette smoking, socio-economic status, or education. The absence of a smoking effect may be attributable to the low level of cigarette usage in these subjects. The average bleomycin-induced damage in the maternal and newborn populations was 0.37 ± 0.27 and 0.15 ± 0.14 breaks per cell, respectively, a difference that was highly significant (p < 0.0001). In newborns there was a positive association between bleomycin sensitivity and the frequencies of aberrations as measured by chromosome painting: p ? 0.0007 for dicentrics and fragments, and p ? 0.002 for translocations. Caucasian American newborns demonstrated a significant association between dicentrics and fragments as measured by painting, and bleomycin sensitivity (p ? 0.0002), but no such association was observed for African American newborns. The results of this study indicate that while differences were observed between African Americans and Caucasian Americans, race does not appear to be a major contributor to chromosome damage in newborns or their mothers. However, peripheral lymphocytes in pregnant women are more susceptible to genetic damage than peripheral lymphocytes in newborns.

Bennett, L. Michelle; Wang, Yun; Ramsey, Marilyn J.; Harger, Gail F.; Bigbee, William L.; Tucker, James D.

2012-01-01

342

Molecular analysis of DiGeorge Syndrome-related translocation breakpoints in 22q11.2  

SciTech Connect

22q11 demonstrates a high frequency of disease-specific rearrangements. Several of the rearrangements are associated with developmental abnormalities such as DiGeorge Syndrome (DGS), Velocardiofacial Syndrome (VCFS), Cat Eye Syndrome (CES) and Supernumerary der(22)t(11;22) Syndrome. DGS and VCFS involve deletions of 22q11.2 resulting from unbalanced translocations or microdeletions. In contrast, CES and Supernumerary der(22)t(11;22) Syndrome result from duplications of this region via inter- or intra- chromosomal exchange. Although the molecular mechanism giving rise to these rearrangements has yet to be elucidated, the presence of known 22q11 repetitive elements are likely to be involved. GM5878 is a 46,XY,t(10;22) cell line from a balanced translocation carrier father of an unbalanced DGS patient. GM0980 is a cell line from a patient with features of DGS/VCFS with an unbalanced karyotype. Using FISH cosmids, we have localized these translocation breakpoints near pH160b (D22S66) which maps to the center of the DiGeorge chromosomal region (DGCR). To further localize the breakpoint of GM5878, overlapping cosmids spanning this region were used as probes for FISH. Use of additional overlapping cosmids allowed the sublocalization of the breakpoint to a 10kb region. A 4.8 kb BglII fragment predicted to cross the breakpoint was isolated. When this fragment was used as a probe to normal and GM5878 DNA, novel bands were detected in GM5878 DNA digested with EcoRI and BglII. Similar analysis of the GM0980 breakpoint is being pursued. Full molecular characterization of these translocations is in progress using inverse PCR to clone the junctional fragments for sequencing. Detailed analysis of the region may reveal molecular features which make this a rearrangement prone area of the genome and help elucidate its relationship to human cytogenetic disease.

Chieffo, C.; Barnoski, B.L.; Emanuel, B.S. [Children`s Hospital of Philadelphia, PA (United States)] [and others

1994-09-01

343

Backgrounds in the NPDGamma Experiment  

NASA Astrophysics Data System (ADS)

The NPDGamma experiment, which measures the parity-violating directional gamma asymmetry in neutron-proton capture, completed its first run cycle in June at the Fundamental Neutron Physics Beamline at the Oak Ridge Spallation Neutron Source. In the experiment intense polarized low-energy neutron beam interacts with liquid para-hydrogen target. Gamma rays from the capture reaction are detected by 48 CsI(Tl) detectors with the 3? acceptance angle. The goal of the experiment is to measure the asymmetry with precision of 1 x10-8. The polarized neutrons also interact with other materials in the beam windows and the walls of the target vessel producing a background to the signal that dilutes the PV gamma asymmetry and these materials (primarily Aluminum) could, in principle, have their own PV asymmetries. Therefore, it is important to study the backgrounds and their contributions to measured signals. I will discuss the detected backgrounds and their effect on NPDGamma.

Kucuker Dogan, Serpil

2012-10-01

344

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

345

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

346

Exotic Branes and Nongeometric Backgrounds  

SciTech Connect

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.

Boer, Jan de; Shigemori, Masaki [Institute for Theoretical Physics, University of Amsterdam Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)

2010-06-25

347

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

348

Background television and reading performance  

Microsoft Academic Search

An experiment was conducted testing Armstrong and Greenberg's (1990) model of the effect of background television on cognitive performance, as it applies to reading comprehension and memory. Subjects completed a cued?recall test of the content of an expository prose passage read under quiet conditions or concurrently with the presence of one of two types of television content (prime?time drama versus

G. Blake Armstrong; Greg A. Boiarsky

1991-01-01

349

Simulation of HEAO 3 background  

NASA Astrophysics Data System (ADS)

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, and decay of nuclei produced by spallation of cosmic rays, trapped protons and their secondaries, the decay of nuclei produced by neutron capture, and the de-excitation of excited states produced by inelastic scattering of neutrons. The method for calculating the nuclear activation and decay component of the background combines the low Earth orbit proton and neutron spectra, the spallation cross sections from Alice91 [2], nuclear decay data from the National Nuclear Data Center's (NNDC) Evaluated Nuclear Structure Data File (ENSDF) database [3], and three-dimensional gamma-ray and beta transport with Electron Gamma-ray Shower version 4 (EGS4) [4] using MORSE combinatorial geometry. This Monte Carlo code handles the following decay types: electron capture, ?-, ?+, meta-stable isotope and short lived intermediate states, and isotopes that have branchings to both ?- and ?+. Actual background from the HEAO 3 space instrument are used to validate the code.

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

1997-05-01

350

Simulation of HEAO 3 background  

SciTech Connect

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, and decay of nuclei produced by spallation of cosmic rays, trapped protons and their secondaries, the decay of nuclei produced by neutron capture, and the de-excitation of excited states produced by inelastic scattering of neutrons. The method for calculating the nuclear activation and decay component of the background combines the low Earth orbit proton and neutron spectra, the spallation cross sections from Alice91, nuclear decay data from the National Nuclear Data Center's (NNDC) Evaluated Nuclear Structure Data File (ENSDF) database, and three-dimensional gamma-ray and beta transport with Electron Gamma-ray Shower version 4 (EGS4) using MORSE combinatorial geometry. This Monte Carlo code handles the following decay types: electron capture, {beta}{sup -}, {beta}{sup +}, meta-stable isotope and short lived intermediate states, and isotopes that have branchings to both {beta}{sup -} and {beta}{sup +}. Actual background from the HEAO 3 space instrument are used to validate the code.

Graham, B. L. [George Mason University, Fairfax, Virginia (United States); Phlips, B. F. [USRA, Washington, District of Columbia (United States); Kroeger, R. A.; Kurfess, J. D. [Naval Research Laboratory, Washington, District of Columbia (United States)

1997-05-10

351

Mathematical background of Parrondo's paradox  

NASA Astrophysics Data System (ADS)

Parrondo's paradox states that there are losing gambling games which, when being combined stochastically or in a suitable deterministic way, give rise to winning games. Here we investigate the probabilistic background. We show how the properties of the equilibrium distributions of the Markov chains under consideration give rise to the paradoxical behavior, and we provide methods how to find the best a priori strategies.

Behrends, Ehrhard

2004-05-01

352

A Little Background Music, Please.  

ERIC Educational Resources Information Center

Background music could be used to provide a pleasant beginning for the school day, to help keep students quiet and relaxed in the school cafeteria at lunchtime, and to provide a midafternoon lift for bored and tired children. The most effective music pleases children without overly exciting them through jarring rhythms and loud dynamics. (nine…

Giles, Martha Mead

1991-01-01

353

The Cosmic Microwave Background Radiation  

NSDL National Science Digital Library

This online article, from Cosmic Horizons: Astronomy at the Cutting Edge, provides an overview of how scientists are working to explain the origin of the universe. Specifically, it discusses the two major theories about the origin of the universe (Big Bang and Steady State), the search for microwave background radiation, and the discovery of the first observational evidence to support the Big Bang theory.

354

Generation of plasmacytomas with the chromosomal translocation t(12;15) in interleukin 6 transgenic mice.  

PubMed Central

The mechanisms through which pristane or mineral oil can induce plasmacytomas in BALB/c or NZB mice are not fully understood, but involvement of interleukin 6 (IL-6), a growth factor for plasmacytomas and myelomas, has been strongly suggested. To clarify the role of IL-6 in plasmacytomagenesis, a human IL-6 cDNA was introduced into mouse germ lines under the transcriptional control of the murine major histocompatibility complex class I (H-2Ld) promoter. IL-6 transgenic mice of C57BL/6 origin developed a massive plasmacytosis but not plasmacytomas. However, introduction of BALB/c genetic background into IL-6 transgenic mice could generate monoclonal transplantable plasmacytomas with the chromosomal translocation t(12;15). These results provide firm evidence of the critical role of IL-6 in the plasmacytoma development. Images

Suematsu, S; Matsusaka, T; Matsuda, T; Ohno, S; Miyazaki, J; Yamamura, K; Hirano, T; Kishimoto, T

1992-01-01

355

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

2013-09-01

356

Human mast cell degranulation and preformed TNF secretion require mitochondrial translocation to exocytosis sites: Relevance to atopic dermatitis  

PubMed Central

Background Mast cells derive from hematopoietic cell precursors and participate in tissue allergic, immune, and inflammatory processes. They secrete many mediators, including preformed TNF, in response to allergic, neuropeptide, and environmental triggers. However, regulation of mast cell degranulation is not well understood. Objective We investigated the role of mitochondrial dynamics in degranulation of human cultured mast cells. Methods Human umbilical cord blood–derived mast cells (hCBMCs) and Laboratory of Allergic Diseases 2 (LAD2) mast cells were examined by confocal and differential interference contrast microscopy during activation by IgE/antigen and substance P (SP). Mast cells in control and atopic dermatitis (AD) skin were evaluated by transmission electron microscopy. LAD2 cells were pretreated with mitochondrial division inhibitor, a dynamin-related protein 1 (Drp1) inhibitor, and small interfering RNA for Drp1, which is necessary for mitochondrial fission and translocation. Calcineurin and Drp1 gene expression was analyzed in stimulated LAD2 cells and AD skin biopsies. Results Stimulation of hCBMCs with IgE/antigen or LAD2 cells with SP leads to rapid (30 minutes) secretion of preformed TNF. Degranulation is accompanied by mitochondrial translocation from a perinuclear location to exocytosis sites. Extracellular calcium depletion prevents these effects, indicating calcium requirement. The calcium-dependent calcineurin and Drp1 are activated 30 minutes after SP stimulation. Reduction of Drp1 activity by mitochondrial division inhibitor and decrease of Drp1 expression using small interfering RNA inhibit mitochondrial translocation, degranulation, and TNF secretion. Mitochondrial translocation is also evident by transmission electron microscopy in skin mast cells from AD biopsies, in which gene expression of calcineurin, Drp1, and SP is higher than in normal skin. Conclusion Human mast cell degranulation requires mitochondrial dynamics, also implicated in AD. (J Allergy Clin Immunol 2011;127:1522-31.)

Zhang, Bodi; Alysandratos, Konstantinos-Dionysios; Angelidou, Asimenia; Asadi, Shahrzad; Sismanopoulos, Nikolaos; Delivanis, Danae-Anastasia; Weng, Zuyi; Miniati, Alexandra; Vasiadi, Magdalini; Katsarou-Katsari, Alexandra; Miao, Benchun; Leeman, Susan E.; Kalogeromitros, Dimitrios; Theoharides, Theoharis C.

2012-01-01

357

Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model  

PubMed Central

Background Experimental studies provide evidence that inhaled nanoparticles may translocate over the airspace epithelium and cause increased cellular inflammation. Little is known, however, about the dependence of particle size or material on translocation characteristics, inflammatory response and intracellular localization. Results Using a triple cell co-culture model of the human airway wall composed of epithelial cells, macrophages and dendritic cells we quantified the entering of fine (1 ?m) and nano-sized (0.078 ?m) polystyrene particles by laser scanning microscopy. The number distribution of particles within the cell types was significantly different between fine and nano-sized particles suggesting different translocation characteristics. Analysis of the intracellular localization of gold (0.025 ?m) and titanium dioxide (0.02–0.03 ?m) nanoparticles by energy filtering transmission electron microscopy showed differences in intracellular localization depending on particle composition. Titanium dioxide nanoparticles were detected as single particles without membranes as well as in membrane-bound agglomerations. Gold nanoparticles were found inside the cells as free particles only. The potential of the different particle types (different sizes and different materials) to induce a cellular response was determined by measurements of the tumour necrosis factor-? in the supernatants. We measured a 2–3 fold increase of tumour necrosis factor-? in the supernatants after applying 1 ?m polystyrene particles, gold nanoparticles, but not with polystyrene and titanium dioxide nanoparticles. Conclusion Quantitative laser scanning microscopy provided evidence that the translocation and entering characteristics of particles are size-dependent. Energy filtering transmission electron microscopy showed that the intracellular localization of nanoparticles depends on the particle material. Both particle size and material affect the cellular responses to particle exposure as measured by the generation of tumour necrosis factor-?.

Rothen-Rutishauser, Barbara; Muhlfeld, Christian; Blank, Fabian; Musso, Claudia; Gehr, Peter

2007-01-01

358

The clinical significance of the FUS-CREB3L2 translocation in low-grade fibromyxoid sarcoma  

PubMed Central

Background Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft-tissue neoplasm with a deceptively benign histological appearance. Local recurrences and metastases can manifest many years following excision. The FUS-CREB3L2 gene translocation, which occurs commonly in LGFMS, may be detected by reverse-transcriptase polymerase chain reaction (RT-PCR) and fluorescence in situ hybridisation (FISH). We assessed the relationship between clinical outcome and translocation test result by both methods. Methods We report genetic analysis of 23 LGFMS cases and clinical outcomes of 18 patients with mean age of 40.6 years. During follow-up (mean 24.8 months), there were no cases of local recurrence or metastasis. One case was referred with a third recurrence of a para-spinal tumour previously incorrectly diagnosed as a neurofibroma. Results Results showed 50% of cases tested positive for the FUS-CREB3L2 translocation by RT-PCR and 81.8% by FISH, suggesting FISH is more sensitive than RT-PCR for confirming LGFMS diagnosis. Patients testing positive by both methods tended to be younger and had larger tumours. Despite this, there was no difference in clinical outcome seen during short and medium-term follow-up. Conclusions RT-PCR and FISH for the FUS-CREB3L2 fusion transcript are useful tools for confirming LGFMS diagnosis, but have no role in predicting medium-term clinical outcome. Due to the propensity for late recurrence or metastasis, wide excision is essential, and longer-term follow-up is required. This may identify a difference in long-term clinical outcome between translocation-positive and negative patients.

2011-01-01

359

Out-of-equilibrium characteristics of a forced translocating chain through a nanopore  

NASA Astrophysics Data System (ADS)

Polymer translocation through a nanopore in a thin membrane is studied using a coarse-grained bead-spring model and Langevin dynamics simulation with a particular emphasis to explore out of equilibrium characteristics of the translocating chain. We analyze the out of equilibrium chain conformations both at the cis and the trans side separately either as a function of the time during the translocation process or as as function of the monomer index m inside the pore. A detailed picture of translocation emerges by monitoring the center of mass of the translocating chain, longitudinal and transverse components of the gyration radii and the end to end vector. We observe that polymer configurations at the cis side are distinctly different from those at the trans side. During the translocation and immediately afterwards, the chain is clearly out of equilibrium, as different parts of the chain are characterized by a series of effective Flory exponents. We further notice that immediately after the translocation the last set of beads that have just translocated take a relatively compact structure compared to the first set of beads that translocated earlier and the chain immediately after translocation is described by an effective Flory exponent 0.45±0.01 . The analysis of these results is further strengthened by looking at the conformations of chain segments of equal length as they cross from the cis to the trans side, We discuss implications of these results to the theoretical estimates and numerical simulation studies of the translocation exponent reported by various groups.

Bhattacharya, Aniket; Binder, Kurt

2010-04-01

360

First-passage-time analysis of DNA translocation in solid-state nanopores  

NASA Astrophysics Data System (ADS)

We report a DNA translocation experiment using solid-state nanopores and 48 kb lambda DNA samples. As reported previously, the DNA translocation dynamics in such standard solid-state nanopore experiments appear to be complex and multiple folded translocation pathways are observable. We use the translocation events with little or no detectable folded structures to construct a distribution function for the DNA translocation times. We find that the translocation time distribution can be fitted using the first-passage-time probability density function derived by Schrodinger for 1-D Brownian motion with a drift. The voltage dependence of the extracted DNA drift velocity shows excellent agreement with the Stokes' law at high voltages. Deviation from the Stokes' law is found at low voltages, but can be attributed to a systematic error in how different types of folded DNA translocations are sorted.

Ling, Daniel; Ling, Xinsheng

2012-02-01

361

Hematotropic parasites of translocated raccoons in the southeast.  

PubMed

Ninety-four raccoons (Procyon lotor) from 6 southeastern states were examined for hematotropic parasites, to evaluate the carrier potential of these animals as they relate to translocation and release for hunting purposes. Four species of hematotropic parasites were identified, viz, Babesia procyonis, Haemobartonella procyoni, Hepatozoon procyonis, and Trypanosoma cruzi. Lesions in infected raccoons were associated only with H procyonis. Babesia procyonis was enzootic in populations of raccoons used as sources for exportation and in raccoons resident in typical release areas. Haemobartonella procyoni, H procyonis, and T cruzi were prevalent only in locales of raccoon origin. Due to the potential pathogenicity of H procyonis and T cruzi in raccoons or other hosts, the practice of translocating raccoons from enzootic to nonenzootic areas was considered biologically hazardous. PMID:104938

Schaffer, G D; Hanson, W L; Davidson, W R; Nettles, V F

1978-11-01

362

Intermediate states during mRNA-tRNA translocation.  

PubMed

Recent studies support the notion that the pre-translocation (PRE) ribosomal complex functions, at least in part, as a Brownian machine, stochastically fluctuating among multiple conformations and transfer RNA (tRNA) binding configurations. Apart from the relatively more energetically stable conformational states of the PRE complex, termed macrostate I (MS I) and macrostate II (MS II), several additional intermediate states have been recently discovered. Structural and kinetic analyses of these states, made possible by cryogenic-electron microscopy (cryo-EM), X-ray crystallography, and single-molecule fluorescence resonance energy transfer (smFRET), have provided important insights into the translocation process, which is now understood to proceed, at least in the first step of the process, as a Brownian machine that is transiently stabilized in the 'productive' MS II conformation by the binding of the translocase elongation factor G (EF-G). PMID:22906732

Frank, Joachim

2012-08-17

363

Post-translational translocation into the endoplasmic reticulum.  

PubMed

Proteins destined for the endomembrane system of eukaryotic cells are typically translocated into or across the membrane of the endoplasmic reticulum and this process is normally closely coupled to protein synthesis. However, it is becoming increasingly apparent that a significant proportion of proteins are targeted to and inserted into the ER membrane post-translationally, that is after their synthesis is complete. These proteins must be efficiently captured and delivered to the target membrane, and indeed a failure to do so may even disrupt proteostasis resulting in cellular dysfunction and disease. In this review, we discuss the mechanisms by which various protein precursors can be targeted to the ER and either inserted into or translocated across the membrane post-translationally. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum. PMID:23266354

Johnson, Nicholas; Powis, Katie; High, Stephen

2012-12-20

364

Mechanism of DNA Translocation in a Replicative Hexameric Helicase  

SciTech Connect

The E1 protein of papillomavirus is a hexameric ring helicase belonging to the AAA + family. The mechanism that couples the ATP cycle to DNA translocation has been unclear. Here we present the crystal structure of the E1 hexamer with single-stranded DNA discretely bound within the hexamer channel and nucleotides at the subunit interfaces. This structure demonstrates that only one strand of DNA passes through the hexamer channel and that the DNA-binding hairpins of each subunit form a spiral 'staircase' that sequentially tracks the oligonucleotide backbone. Consecutively grouped ATP, ADP and apo configurations correlate with the height of the hairpin, suggesting a straightforward DNA translocation mechanism. Each subunit sequentially progresses through ATP, ADP and apo states while the associated DNA-binding hairpin travels from the top staircase position to the bottom, escorting one nucleotide of single-stranded DNA through the channel. These events permute sequentially around the ring from one subunit to the next.

Enemark,E.; Joshua-Tor, L.

2006-01-01

365

Markov chain modeling of polymer translocation through pores.  

PubMed

We solve the Chapman-Kolmogorov equation and study the exact splitting probabilities of the general stochastic process which describes polymer translocation through membrane pores within the broad class of Markov chains. Transition probabilities, which satisfy a specific balance constraint, provide a refinement of the Chuang-Kantor-Kardar relaxation picture of translocation, allowing us to investigate finite size effects in the evaluation of dynamical scaling exponents. We find that (i) previous Langevin simulation results can be recovered only if corrections to the polymer mobility exponent are taken into account and (ii) the dynamical scaling exponents have a slow approach to their predicted asymptotic values as the polymer's length increases. We also address, along with strong support from additional numerical simulations, a critical discussion which points in a clear way the viability of the Markov chain approach put forward in this work. PMID:21950882

Mondaini, Felipe; Moriconi, L

2011-09-21

366

Faithful after break-up: suppression of chromosomal translocations.  

PubMed

Chromosome integrity in response to chemically or radiation-induced chromosome breaks and the perturbation of ongoing replication forks relies on multiple DNA repair mechanisms. However, repair of these lesions may lead to unwanted chromosome rearrangement if not properly executed or regulated. As these types of chromosomal alterations threaten the cell's and the organism's very own survival, multiple systems are developed to avoid or at least limit break-induced chromosomal rearrangements. In this review, we highlight cellular strategies for repressing DNA break-induced chromosomal translocations in multiple model systems including yeast, mouse, and human. These pathways select proper homologous templates or broken DNA ends for the faithful repair of DNA breaks to avoid undesirable chromosomal translocations. PMID:19547915

Lee, Sang Eun; Myung, Kyungjae

2009-06-23

367

Translocation-associated Salivary Gland Tumors: A Review and Update.  

PubMed

In recent years the discovery of translocations and the fusion oncogenes that they result in has changed the way diagnoses are made in the salivary gland. These genetic aberrations are recurrent and reproducible and at the very least serve as powerful diagnostic tools in salivary gland diagnosis and salivary gland classification. They also show promise as prognostic markers and hopefully as targets of therapy. Many of these fusions have been found in other tumor types that show little to no overlap with their salivary gland counterparts, but effectively they are specific within the salivary gland. In this review the 5 tumors currently known to harbor translocations will be discussed, namely pleomorphic adenoma, mucoepidermoid carcinoma, adenoid cystic carcinoma, mammary analog secretory carcinoma, and hyalinizing clear cell carcinoma. The discovery and implications of each fusion will be highlighted and how they have helped reshape the current classification of salivary gland tumors. PMID:24113307

Weinreb, Ilan

2013-11-01

368

Translocation (5; 11) in a conjunctival MALT lymphoma  

PubMed Central

Lymphoma is the most frequent malignant tumor of the ocular adnexa with the most common histologic type being extranodal marginal zone B-cell lymphoma (EMZL) of mucosa-associated lymphoid tissue (MALT lymphoma). Here we report a case of a 28 year-old male who presented with a left conjunctival mass of one year duration. A diagnosis of primary MALT lymphoma of the conjunctiva was made based on morphologic and immunopheno-typic studies. Chromosome analysis revealed a male karyotype with a translocation t (5;11) (q33;p11.2) as the primary chromosomal abnormality, which, to the best of our knowledge, is the first reported translocation in MALT lym-phomas and ocular MALT lymphomas as well.

Clement, Cecilia G; Potluri, Venkateswara R; Gonzales, John; Qian, You-Wen

2011-01-01

369

Cryptic translocation t(5;18) in familial mental retardation.  

PubMed

A cryptic translocation t(5;18)(qter;qter) was detected in a large family, using a FISH-based approach combining subtelomeric probes to allow the subtelomeric regions of most chromosome ends to be analysed for deletions and balanced or unbalanced translocations. Unbalanced karyotypes (duplication 5qter/deficiency 18qter) resulted in a previously undescribed association of moderate to severe mental retardation, microcephaly, pre- and postnatal growth retardation, distinct facial dysmorphism, narrow auditory canals, genital hypoplasia, left heart hypoplasia in one patient and severe behaviour difficulties in another. Some of the features observed in affected individuals are characteristic of known syndromes involving either 18q (growth deficiency, nystagmus, narrow auditory canals, genital hypoplasia, behaviour problems in 18q deletion syndrome) or 5q (umbilical and inguinal hernias, congenital heart defects in distal 5q trisomy). PMID:11164192

Vogels, A; Devriendt, K; Vermeesch, J R; Van Dael, R; Marynen, P; Dewaele, P; Hageman, J; Holvoet, M; Fryns, J P

370

Sinuous antennas for cosmic microwave background polarimetry  

NASA Astrophysics Data System (ADS)

We are developing antenna-coupled Transition Edge Sensor (TES) bolometers to be used in the focal planes of telescopes mapping Cosmic Microwave Background (CMB) polarization anisotropies. These detectors will be both dual-polarized and ultra-wide band, each containing several frequency channels. Arrays of such detectors could realize mapping speeds nearly an order of magnitude higher than previously deployed technology while naturally facilitating foreground removal. For such detectors to be useful, the antennas must have a high gain and a low cross-polarization. We have designed a novel modification of DuHamel's Sinuous antenna that couples to a contacting lens and is driven by integrated microstrip feed-lines. The integrated feed lines allow the antenna to interface with microstrip circuits and bolometers in a way that is planar and scalable to kilo-pixel arrays. We have demonstrated the polarization and beam properties with scale model antennas that operate at 1-12 GHz.

O'Brient, Roger; Edwards, Jennifer; Arnold, Kam; Engargiola, Greg; Holzapfel, William; Lee, Adrian T.; Myers, Michael; Quealy, Erin; Rebeiz, Gabriel; Richards, Paul; Spieler, Helmuth; Tran, Huan

2008-08-01

371

Observer models for statistically-defined backgrounds  

NASA Astrophysics Data System (ADS)

Investigation of human signal-detection performance for noise- limited tasks with statistically defined signal or image parameters represents a step towards clinical realism. However, the ideal observer procedure is then usually nonlinear, and analysis becomes mathematically intractable. Two linear but suboptimal observer models, the Hotelling observer and the non- prewhitening (NPW) matched filter, have been proposed for mathematical convenience. Experiments by Rolland and Barrett involving detection of signals in white noise superimposed on statistically defined backgrounds showed that the Hotelling model gave a good fit while the simple NPW matched filter gave a poor fit. It will be shown that the NPW model can be modified to fit their data by adding a spatial frequency filter of shape similar to the human contrast sensitivity function. The best fit is obtained using an eye filter model, E(f) equals f1.3 exp(-cf2) with c selected to give a peak at 4 cycles per degree.

Burgess, Arthur E.

1994-04-01

372

Background stratospheric aerosol reference model  

NASA Astrophysics Data System (ADS)

In this analysis, a reference background stratospheric aerosol optical model is developed based on the nearly global SAGE 1 satellite observations in the non-volcanic period from March 1979 to February 1980. Zonally averaged profiles of the 1.0 micron aerosol extinction for the tropics and the mid- and high-altitudes for both hemispheres are obtained and presented in graphical and tabulated form for the different seasons. In addition, analytic expressions for these seasonal global zonal means, as well as the yearly global mean, are determined according to a third order polynomial fit to the vertical profile data set. This proposed background stratospheric aerosol model can be useful in modeling studies of stratospheric aerosols and for simulations of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing.

McCormick, M. P.; Wang, P.

1989-12-01

373

WFC3/UVIS Sky Backgrounds  

NASA Astrophysics Data System (ADS)

This report summarizes the on-orbit background levels present in WFC3/UVIS full-frame images. The results are based on nearly all standard readout images taken since the installation of WFC3 on HST in May 2009, with a relatively small number of exclusions e.g. images with obvious anomalous backgrounds (such as extended targets filling the field of view) or those taken with the quad filters (different bandpass in each amp). Comparisons are provided to estimates from the Exposure Time Calculator (ETC). We anticipate these results to be helpful in fine-tuning the level of post-flash required to achieve the optimum balance of charge transfter efficiency (CTE) loss mitigation versus noise penalty. Observers considering the use of post-flash should refer to the White Paper (MacKenty & Smith 2012) on the CTE WWW page (http://www.stsci.edu/hst/wfc3/ins_performance/CTE/).

Baggett, Sylvia; Anderson, Jay

2012-06-01

374

MiniCLEAN surface backgrounds  

Microsoft Academic Search

MiniCLEAN is a dark matter experiment using 150kg fiducial mass of liquid cryogen (argon or neon) to search for Weakly Interacting Massive Particles (WIMPs). MiniCLEAN seeks to detect scintillation photons from WIMP-induced argon recoils. A potentially dominant background is from alpha decays on the inner surfaces of the containment vessel. Such events can mimic the prompt signal characteristic of nuclear

Boqian Wang; Richard Schnee

2011-01-01

375

The cosmic infrared background experiment  

Microsoft Academic Search

The extragalactic background, based on absolute measurements reported by DIRBE and IRTS at 1.2 and 2.2?m, exceeds the brightness derived from galaxy counts by up to a factor 5. Furthermore, both DIRBE and the IRTS report fluctuations in the near-infrared sky brightness that appear to have an extra-galactic origin, but are larger than expected from local (z=1–3) galaxies. These observations

James Bock; John Battle; Asantha Cooray; Mitsunobu Kawada; Brian Keating; Andrew Lange; Dae-Hea Lee; Toshio Matsumoto; Shuji Matsuura; Soojong Pak; Tom Renbarger; Ian Sullivan; Kohji Tsumura; Takehiko Wada; Toyoki Watabe

2006-01-01

376

Anisotropies of cosmic microwave background  

NASA Astrophysics Data System (ADS)

Cosmic microwave background (CMB) anisotropies have been recognized as one of the most important observational quantities to understand the early stage of our universe. Here it is shown that temperature fluctuations of CMB contain rich information, i.e., cosmological parameters, geometry of the universe, initial condition of the density perturbations and more. The impact by recent observations of BOOMERanG and MAXIMA is also mentioned.

Sugiyama, Naoshi

2001-07-01

377

Embryological background for fetal surgery.  

PubMed

Congenital malformations are one of the main topics, which must be addressed in the 21st century. Fetal surgery is expected to become a routine procedure for malformed fetal patients in the near future. This paper presents some important aspects of the embryological background required for fetal surgery and shows normal human embryos between the 4th and the 8th week of development. PMID:11754144

Park, H W

2001-12-01

378

Electromagnetic scattering in polarizable backgrounds  

Microsoft Academic Search

We develop a fully vectorial formalism for the investigation of electromagnetic scattering in polarizable backgrounds, i.e., where the scatterers are not in vacuum but situated in a medium with a dielectric permittivity different from unity. Our approach is based on the Green's tensor technique and the corresponding Green's tensors for two-dimensional ~2D! and three-dimensional ~3D! systems are developed. The analysis

Olivier J. F. Martin; Nicolas B. Piller

1998-01-01

379

Child with Sotos phenotype and a 5:15 translocation  

SciTech Connect

The authors report on a 4-year-old girl with Sotos phenotype and a de novo balanced translocation between the long arms of chromosome 5 and chromosome 15 [46,XX,t(5,15)(q35;q22)]. They suggest a relationship between genetic material at 5q35 or 15q22 and the expression of an autosomal dominant gene. 18 refs., 2 figs.

Maround, C.; Schmerler, S.; Hutcheon, R.G. [St. Joseph`s Hospital and Medical Center, Paterson, NJ (United States)

1994-04-15

380

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

381

The uptake, translocation and release of phosphorus by Elodea densa  

Microsoft Academic Search

Short-term (16 h) laboratory studies of 32P uptake by Elodea densa rooted in sediment demonstrated both foliar and root uptake, and that translocation occurred acropetally and basipetally.\\u000a Root absorption is projected to provide 83–85% of total phosphorus uptake during 12–16 h photoperiod days. Measured foliar\\u000a uptake and excretion rates suggest that there would be no net leakage of phosphorus into

J. O. Gabrielson; M. A. Perkins; E. B. Welch

1984-01-01

382

An investigation of bidirectional translocation in the Phloem.  

PubMed

Patterns of (14) CO(2) , assimilate movement in Vicia jaba plants having 7 nodes were studied. Bidirectional translocation occurred throughout most of the stem length when tracer was applied to leaves of various ages. To determine whether this bidirectional translocation occurs within single sieve tubes, a O.1 % solution of the fluorescent dye K-fluorescein was applied to a lightly scraped area on the stem in the middle of a young internode. After one hour the dye was present short distances above and below the treated area. Free-hand sections of the internode showed the dye to be localized in the traces of the larger leaves below tbe treated area and in the traces of the younger leaves above the treated area. The dye was never present in the same bundle both above and below the treated area, indicating that each bundle and sieve tube translocated the dye in only one direction. These results were confirmed using Phaseolus vulgaris, Vinca rosea, and Pelargonium hortum. A similar study in which petioles of young Ecballium elaterium leaves were treated showed that usually the phloem of one bundle translocated the dye in only one direction but in some cases the external phloem of the bicollateral bundles carried the dye toward the stem while the internal phloem carried the dye toward the blade. When longer time intervals were used in all these experiments, the dye sometimes appeared in the same phloem areas both above and below the treated area. This is explained by a lateral transfer of tracer within the phloem, either through secondary phloem or through bundle anastomoses at the nodes. PMID:20925674

Peterson, C; Currier, H B

1969-01-01

383

Dominant-lethal mutations and heritable translocations in mice  

Microsoft Academic Search

Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of

Generoso

1983-01-01

384

Kinetic characteristics of photoassimilate translocation in Alaria esculenta (Laminariales, Phaeophyceae)  

Microsoft Academic Search

The kinetics of translocation of 14C-labeled photoassimilate were studied in the kelp, Alaria esculenta (L.) Grev., using a Geiger-Müller detector-probe to measure radioactivity in the source and sink regions of dumbbell-shaped explants cut from blades. Rapid tracer efflux from the source occurred for 4 days following a pulse of [14C]bicarbonate, with 40–60% of the initial activity remaining in the source

Richard G. Buggeln; Steven Lucken

1979-01-01

385

The identification of rye trisomics by translocations and Giemsa staining  

Microsoft Academic Search

By the Giemsa C-banding of six rye (Secale cereale) trisomics and by crossing them to translocation tester stocks it was possible to identify the trisomics and the tester stocks so that their correspondence to the wheat homoeologous groups could be established. The Heines Hellkorn trisomics 1\\/23, 4\\/11, 4\\/9, 1\\/19, 1\\/21 and 3\\/23 were found to correspond to Sears' Chinese Spring\\/Imperial

F. J. Zeller; G. Kimber; Bikram S. Gill

1977-01-01

386

Centromeric inactivation in a dicentric human Y;21 translocation chromosome  

Microsoft Academic Search

.?  A de novo dicentric Y;21 (q11.23;p11) translocation chromosome with one of its two centromeres inactive has provided the opportunity\\u000a to study the relationship between centromeric inactivation, the organization of alphoid satellite DNA and the distribution\\u000a of CENP-C. The proband, a male with minor features of Down’s syndrome, had a major cell line with 45 chromosomes including\\u000a a single copy of

Andrew M. Fisher; Lihadh Al-Gazali; T. Pramathan; Roger Quaife; Annette E. Cockwell; John C. K. Barber; William C. Earnshaw; Joyce Axelman; Barbara R. Migeon; Chris Tyler-Smith

1997-01-01

387

Human gene mapping using an X\\/autosome translocation  

Microsoft Academic Search

Human fibroblasts containing a translocation between the X chromosome and chromosome 15 were fused with the 6-thioguanine-resistant mouse cell line, IR. Resulting hybrids, selected in HAT medium, retained the X\\/15 chromosome. Hybrids which were counterselected in 6-thioguanine lost this chromosome. The X-linked markers glucose-6-phosphate dehydrogenase (G6PD), phosphoglycerate kinase (PGK), and hypoxanthine phosphoribosyl transferase (HPRT), and the non-X-linked markers pyruvate kinase

E. Solomon; M. Bobrow; P. N. Goodfellow; W. F. Bodmer; D. M. Swallow; S. Povey; B. Noël

1976-01-01

388

Seaside transportation--from structure to function of translocation machines.  

PubMed

The EMBO conference 'From Structure to Function of Translocation Machines' took place in April 2013 in Dubrovnik, Croatia. The meeting brought together a mix of established and aspiring researchers to discuss a wealth of unpublished data and ideas in a lively scientific programme of talks designed to shatter the established dogma. From new ways to envisage known protein transport pathways to a brand new and totally unconventional protein transport system, surprises were part and parcel of this excellent EMBO conference. PMID:23764920

Lithgow, Trevor; Waksman, Gabriel

2013-06-14

389

Backgrounds and characteristics of arsonists.  

PubMed

The aim of this study was to gain more insight in the backgrounds and characteristics of arsonists. For this, the psychiatric, psychological, personal, and criminal backgrounds of all arsonists (n=25), sentenced to forced treatment in the maximum security forensic hospital "De Kijvelanden", were compared to the characteristics of a control group of patients (n=50), incarcerated at the same institution for other severe crimes. Apart from DSM-IV Axis I and Axis II disorders, family backgrounds, level of education, treatment history, intelligence (WAIS scores), and PCL-R scores were included in the comparisons. Furthermore, the apparent motives for the arson offences were explored. It was found that arsonists had more often received psychiatric treatment, prior to committing their index offence, and had a history of severe alcohol abuse more often in comparison to the controls. The arsonists turned out to be less likely to suffer from a major psychotic disorder. Both groups did not differ significantly on the other variables, among which the PCL-R total scores and factor scores. Exploratory analyses however, did suggest that arsonists may differentiate from non-arsonists on three items of the PCL-R, namely impulsivity (higher scores), superficial charm (lower scores), and juvenile delinquency (lower scores). Although the number of arsonists with a major psychotic disorder was relatively low (28%), delusional thinking of some form was judged to play a role in causing arson crimes in about half of the cases (52%). PMID:20434774

Labree, Wim; Nijman, Henk; van Marle, Hjalmar; Rassin, Eric

390

Kinetic mechanism of translocation and dNTP binding in individual DNA polymerase complexes.  

PubMed

Complexes formed between phi29 DNA polymerase (DNAP) and DNA fluctuate discretely between the pre-translocation and post-translocation states on the millisecond time scale. The translocation fluctuations can be observed in ionic current traces when individual complexes are captured atop the ?-hemolysin nanopore in an electric field. The presence of complementary 2'-deoxynucleoside triphosphate (dNTP) shifts the equilibrium across the translocation step toward the post-translocation state. Here we have determined quantitatively the kinetic relationship between the phi29 DNAP translocation step and dNTP binding. We demonstrate that dNTP binds to phi29 DNAP-DNA complexes only after the transition from the pre-translocation state to the post-translocation state; dNTP binding rectifies the translocation but it does not directly drive the translocation. Based on the measured time traces of current amplitude, we developed a method for determining the forward and reverse translocation rates and the dNTP association and dissociation rates, individually at each dNTP concentration and each voltage. The translocation rates, and their response to force, match those determined for phi29 DNAP-DNA binary complexes and are unaffected by dNTP. The dNTP association and dissociation rates do not vary as a function of voltage, indicating that force does not distort the polymerase active site and that dNTP binding does not directly involve a displacement in the translocation direction. This combined experimental and theoretical approach and the results obtained provide a framework for separately evaluating the effects of biological variables on the translocation transitions and their effects on dNTP binding. PMID:23705688

Lieberman, Kate R; Dahl, Joseph M; Mai, Ai H; Cox, Ashley; Akeson, Mark; Wang, Hongyun

2013-06-07

391

Single-molecule studies of bacterial protein translocation.  

PubMed

In prokaryotes, a large share of the proteins are secreted from the cell through a process that requires their translocation across the cytoplasmic membrane. This process is mediated by the universally conserved Sec system with homologues in the endoplasmic reticulum and thylakoid membranes of eukaryotes. The Sec system also facilitates the membrane insertion of integral membrane proteins, an essential step along their folding pathway. In bacteria, the Sec system consists of the protein-conducting channel (SecYEG) that associates with soluble components, such as the motor protein SecA or translating ribosomes, and with integral membrane proteins, such as the heterotrimeric complex termed SecDFyajC and the YidC insertase. Over the past three decades, biochemical and structural studies have provided a comprehensive view of protein translocation, but the exact mechanistic details of this process remain to be resolved. For a number of other biomolecular systems, single-molecule biophysical analysis has efficiently complemented the conventional biochemical studies conducted in bulk, with high-sensitivity measurements probing the structure and dynamics of individual molecules in vitro and in vivo. Here, we review recent advances in studies of protein translocation employing single-molecule techniques with the aim of resolving molecular mechanisms, thereby providing a new and detailed view of the process. PMID:24024480

Kedrov, Alexej; Kusters, Ilja; Driessen, Arnold J M

2013-09-19

392

Dieldrin uptake and translocation in plants growing in hydroponic medium.  

PubMed

It has been known that the Cucurbitaceae family takes up a large amount of persistent organic pollutants from soils and that the translocation of those compounds in cucurbits is higher than those in non-cucurbits. To understand the persistent organic pollutant uptake mechanisms of plant species, we compared the dieldrin absorption and transportation potentials of several plants in hydroponic medium. Sorghum (Sorghum vulgare Moench), sunflower (Helianthus annuus L.), soybean (Glycine max), komatsuna (Brassica rapa var. peruviridis), white-flowered gourd (Lagenaria siceraria var. hispida), cucumber (Cucumis sativus L.), and zucchini (Cucurbita pepo L.) were grown in a dieldrin-added hydroponic medium for 10 d, and then the amount of dieldrin in their shoots and roots was measured. All of the roots contained dieldrin, whereas only the cucurbits (white-flowered gourd, cucumber, and zucchini) contained considerable amounts of dieldrin in their shoots. The dieldrin uptake to the roots depended on the concentration of the n-hexane soluble components in the roots, regardless of whether the dieldrin in the roots was translocated to shoots or not. The dieldrin uptake from the solution to the roots was thought to be due to a passive response, such as adsorption on the roots. The translocation of dieldrin from the roots to the shoots was probably through the xylems. The amounts of dieldrin in the shoots per transpiration rates were higher for cucurbits than for non-cucurbits. It seems likely that cucurbits have uptake mechanisms for hydrophobic organic chemicals. PMID:20821429

Murano, Hirotatsu; Otani, Takashi; Seike, Nobuyasu; Sakai, Mizuki

2010-01-01

393

Aminoglycoside activity observed on single pre-translocation ribosome complexes  

PubMed Central

Aminoglycoside-class antibiotics bind directly to ribosomal RNA, imparting pleiotropic effects on ribosome function. Despite in-depth structural investigations of aminoglycoside–RNA oligonucleotide and aminoglycoside-ribosome interactions, mechanisms explaining the unique ribosome inhibition profiles of chemically similar aminoglycosides remain elusive. Here, using single-molecule fluorescence resonance energy transfer (smFRET) methods, we show that high-affinity aminoglycoside binding to the conserved decoding site region of the functional pre-translocation ribosome complex specifically remodels the nature of intrinsic dynamic processes within the particle. The extents of these effects, which are distinct for each member of the aminoglycoside class, strongly correlate with their inhibition of EF-G–catalyzed translocation. Neomycin, a 4,5-linked amino-glycoside, binds with lower affinity to one or more secondary binding sites, mediating distinct structural and dynamic perturbations that further enhance translocation inhibition. These new insights help explain why closely related aminoglycosides elicit pleiotropic translation activities and demonstrate the potential utility of smFRET as a tool for dissecting the mechanisms of antibiotic action.

Feldman, Michael B; Terry, Daniel S; Altman, Roger B; Blanchard, Scott C

2010-01-01

394

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

395

Aminoglycoside activity observed on single pre-translocation ribosome complexes  

PubMed Central

Aminoglycoside-class antibiotics bind directly to ribosomal RNA, imparting pleiotropic effects on ribosome function. Despite in-depth structural investigations of aminoglycoside–RNA oligonucleotide and aminoglycoside-ribosome interactions, mechanisms explaining the unique ribosome inhibition profiles of chemically similar aminoglycosides remain elusive. Here, using single-molecule fluorescence resonance energy transfer (smFRET) methods, we show that high-affinity aminoglycoside binding to the conserved decoding site region of the functional pre-translocation ribosome complex specifically remodels the nature of intrinsic dynamic processes within the particle. The extents of these effects, which are distinct for each member of the aminoglycoside class, strongly correlate with their inhibition of EF-G–catalyzed translocation. Neomycin, a 4,5-linked aminoglycoside, binds with lower affinity to one or more secondary binding sites, mediating distinct structural and dynamic perturbations that further enhance translocation inhibition. These new insights help explain why closely related aminoglycosides elicit pleiotropic translation activities and demonstrate the potential utility of smFRET as a tool for dissecting the mechanisms of antibiotic action.

Feldman, Michael B; Terry, Daniel S; Altman, Roger B; Blanchard, Scott C

2013-01-01

396

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

397

An emerging consensus on aquaporin translocation as a regulatory mechanism.  

PubMed

Water passes through cell membranes relatively slowly by diffusion. In order to maintain water homeostasis, the rapid and specific regulation of cellular water flow is mediated by the aquaporin (AQP) family of membrane protein water channels. The wide range of tissues that are known to express AQPs is reflected by their involvement in many physiological processes and diseases; thirteen human AQPs have been identified to date and the majority are highly specific for water while others show selectivity for water, glycerol and other small solutes. Receptor mediated translocation, via hormone activation, is an established method of AQP regulation, especially for AQP2. There is now an emerging consensus that the rapid and reversible translocation of other AQPs from intracellular vesicles to the plasma membrane, triggered by a range of stimuli, confers altered membrane permeability thereby acting as a regulatory mechanism. This review examines the molecular components that may enable such AQP regulation; these include cytoskeletal proteins, kinases, calcium and retention or localization signals. Current knowledge on the dynamic regulation of sub-cellular AQP translocation in response to a specific trigger is explored in the context of the regulation of cellular water flow. PMID:23170905

Conner, Alex C; Bill, Roslyn M; Conner, Matthew T

2012-11-21

398

Domain motions of hyaluronan lyase underlying processive hyaluronan translocation.  

PubMed

Hyaluronan lyase (Hyal) is a surface enzyme occurring in many bacterial organisms including members of Streptococcus species. Streptococcal Hyal primarily degrades hyaluronan-substrate (HA) of the extracellular matrix. This degradation appears to facilitate the spread of this bacterium throughout host tissues. Unlike purely endolytic degradation of its other substrates, unsulfated chondroitin or some chondroitin sulfates, the degradation of HA by Hyal proceeds by processive exolytic cleavage of one disaccharide at a time following an initial endolytic cut. Molecular dynamics (MD) studies of Hyal from Streptococcus pneumoniae are presented that address the enzyme's molecular mechanism of action and the role of domain motions for processive functionality. The analysis of extensive sub-microsecond MD simulations of this enzyme action on HA-substrates of different lengths and the connection between the domain dynamics of Hyal and the translocation of the HA-substrate reveals that opening/closing and twisting domain motions of the Hyal are intimately linked to processive HA degradation. Enforced simulations confirmed this finding as the domain motions in SpnHyal were found to be induced by enforced substrate translocation. These results establish the dynamic interplay between Hyal flexibility and substrate translocation and provide insight into the processive mechanism of Hyal. PMID:19089975

Joshi, Harshad V; Jedrzejas, Mark J; de Groot, Bert L

2009-07-01

399

Small bowel transplantation promotes bacterial overgrowth and translocation.  

PubMed

Alterations in the symbiotic relationship between immunocompromised hosts and their resident gut microflora may lead to serious complications following small bowel transplantation (SBT). This study examined the effects of SBT and cyclosporine (CsA) immunosuppression on gut bacterial populations and translocation to the mesenteric lymph nodes. Sixty adult male meat-fed Lewis rats were divided into six groups: normal controls, CsA alone (24 mg/kg im qod), CsA carrier vehicle alone, isografts, isografts given CsA, and allografts given CsA. Rats were killed after 3 weeks and segments of small bowel and colon were harvested for quantitative tissue culture. Mesenteric lymph nodes and blood were cultured to identify translocation. Transplantation alone led to an increase in gram-negative aerobes from 2.6 to 4.6 colony forming units/100 mg tissue (P less than 0.05) in the distal ileum (transplanted segment). Eighty-four percent of transplanted animals receiving CsA had bacteria recovered from their mesenteric lymph nodes compared to none in controls (P less than 0.001) and 20% in isografts not receiving CsA (P less than 0.02). Intestinal transplantation alone appears to promote gram-negative overgrowth while the addition of CsA therapy facilitates translocation to the mesenteric lymph nodes and may predispose to gut-associated sepsis following SBT. PMID:1943089

Browne, B J; Johnson, C P; Edmiston, C E; Hlava, M A; Moore, G H; Roza, A M; Telford, G L; Adams, M B

1991-12-01

400

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

401

Dominant-lethal mutations and heritable translocations in mice  

SciTech Connect

Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of these two endpoints appears to be determined by the stability of alkylation products with the chromosomes. If the reaction products are intact in the male chromosomes at the time of sperm entry, they may be repaired in fertilized eggs. If repair is not effected and the alkylation products persist to the time of pronuclear chromosome replication, they lead to chromatid-type aberrations and eventually to dominant-lethality. The production of heritable translocations, on the other hand, requires a transformation of unstable alkylation products into suitable intermediate lesions. The process by which these lesions are converted into chromosome exchange within the male genome takes place after sperm enters the egg but prior to the time of pronuclear chromosome replication (i.e., chromosome-type). Thus, dominant-lethal mutations result from both chromatid- and chromosome-type aberrations while heritable translocations result primarily from the latter type. DNA target sites associated with the production of these two endpoints are discussed.

Generoso, W.M.

1983-01-01

402

Accuracy, lesion bypass, strand displacement and translocation by DNA polymerases.  

PubMed Central

The structures of DNA polymerases from different families show common features and significant differences that shed light on the ability of these enzymes to accurately copy DNA and translocate. The structure of a B family DNA polymerase from phage RB69 exhibits an active-site closing conformational change in the fingers domain upon forming a ternary complex with primer template in deoxynucleoside triphosphate. The rotation of the fingers domain alpha-helices by 60 degrees upon dNTP binding is analogous to the changes seen in other families of polymerases. When the 3' terminus is bound to the editing 3' exonuclease active site, the orientation of the DNA helix axis changes by 40 degrees and the thumb domain re-orients with the DNA. Structures of substrate and product complexes of T7 RNA polymerase, a structural homologue of T7 DNA polymerase, show that family polymerases use the rotation conformational change of the fingers domain to translocate down the DNA. The fingers opening rotation that results in translocation is powered by the release of the product pyrophosphate and also enables the Pol I family polymerases to function as a helicase in displacing the downstream non-template strand from the template strand.

Steitz, Thomas A; Yin, Y Whitney

2004-01-01

403

Bacterial translocation from the gut impairs systemic immunity.  

PubMed

The goal of this study was to determine the influence of bacterial translocation on systemic immunity, since bacteria and their products play a major role in the development and maintenance of the host's immune system. To test this hypothesis, we measured the blastogenic response of mononuclear cells harvested from the blood, spleen, Peyer's patches, and mesenteric lymph nodes of control and Escherichia coli C25 monoassociated mice to a battery of mitogens. The E. coli C25 monoassociation model was used because this bacterial translocation model is not associated with experimental manipulations that are likely to affect the systemic immune system. The mitogenic response of lymphocytes isolated from the E. coli C25 monoassociated mice was significantly depressed compared to the control groups (p less than 0.01). Since the biologic significance of depressed in vitro mitogen responsiveness is difficult to determine, we assessed the ability of the mice to control a bacterial challenge using an in vivo Staphylococcus aureus abscess model. It appears that the observed changes in mitogen responsiveness may be of biologic significance, since the ability of the E. coli C25 monoassociated mice to control the injected S. aureus was impaired (p less than 0.01). These results suggest that an association exists between bacterial translocation and decreased systemic immune responsiveness. PMID:2000558

Deitch, E A; Xu, D Z; Qi, L; Berg, R D

1991-03-01

404

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

405

Stochastic gravitational-wave background from cosmological supernovae  

SciTech Connect

Based on new developments in the understanding of supernovae (SNe) as gravitational-wave (GW) sources we estimate the GW background from all cosmic SNe. For a broad range of frequencies around 1 Hz, this background is crudely comparable to the GW background expected from standard inflationary models. While our estimate remains uncertain within several orders of magnitude, the SN GW background may become detectable by second-generation space-based interferometers such as the proposed Big Bang Observatory (BBO). By the same token, the SN GWs may become a foreground for searches of the inflationary GWs, in particular, for sub-Hz frequencies where the SN background is Gaussian and where the BBO will be most sensitive. SN simulations lasting far beyond the usual cutoff of about 1 s are needed for more robust predictions in the sub-Hz frequency band. An even larger GW background can arise from a hypothetical early population of massive stars, although their GW source strength as well as their abundance are currently poorly understood.

Buonanno, Alessandra; Sigl, Guenter [GReCO, Institut d'Astrophysique de Paris, C.N.R.S., 98 bis boulevard Arago, F-75014 Paris (France); AstroParticule et Cosmologie (APC), 11, place Marcelin Berthelot, F-75005 Paris (France); Raffelt, Georg G. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 Munich (Germany); Janka, Hans-Thomas; Mueller, Ewald [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)

2005-10-15

406

Non-thermal cosmic backgrounds from blazars: the contribution to the CMB, X-ray and gamma-ray backgrounds  

Microsoft Academic Search

We present a new assessment of the contribution of the blazar population to the extragalactic background radiation across the electromagnetic spectrum. Our calculations rely on deep blazar radio counts that we have derived by combining several radio and multi-frequency surveys. We show that blazar emission integrated over cosmic time gives rise to a considerable broad-band non-thermal cosmic background that in

P. Giommi; S. Colafrancesco; E. Cavazzuti; M. Perri; C. Pittori

2006-01-01

407

Background concentrations of reactive gases and the impacts of long-range transport at the Jinsha regional atmospheric background station  

Microsoft Academic Search

Lorentz curve fittings are applied to frequency distributions of the concentrations of O3, CO, NO\\u000a x\\u000a and SO2 recorded at the Jinsha regional atmospheric background station (JSH) from June 2006 to July 2007, and the peak concentrations\\u000a of these species for the different seasons are obtained. The peak concentrations are considered to be representative of different\\u000a background levels for certain

WeiLi Lin; XiaoBin Xu; JunYing Sun; XiWen Liu; Ying Wang

408

Insulin translocates PKC? and phorbol esters induce and persistently translocate PKC ? 2 in BC3H-1 myocytes  

Microsoft Academic Search

Initial studies suggested that insulin increases diacylglycerol and activates protein kinase C (PKC) in BC3H-1 myocytes. In these earlier studies, insulin was found to translocate PKC-?, but the presence of PKC-? was not appreciated. More recently, the presence of PKC-? was documented, but PKC-? was not detected, and it was questioned whether insulin activates PKC in BC3H-1 myocytes [Stumpo, D.J.,

Mary L. Standaert; Antoine Avignon; Thomas Arnold; Sherene I. Saba-Siddique; Denise R. Cooper; James Watson; Xiaopeng Zhou; Lamar Galloway; Robert V. Farese

1996-01-01

409

DNA sequencing using fluorescence background electroblotting membrane  

DOEpatents

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through said smino groups contained on the surface thereof. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to said target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membrances may be reprobed numerous times.

Caldwell, Karin D. (Salt Lake City, UT); Chu, Tun-Jen (Salt Lake City, UT); Pitt, William G. (Orem, UT)

1992-01-01

410

DNA sequencing using fluorescence background electroblotting membrane  

DOEpatents

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through amino groups contained on the surface. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to the target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membranes may be reprobed numerous times. No Drawings

Caldwell, K.D.; Chu, T.J.; Pitt, W.G.

1992-05-12

411

Isolation and analysis of the 21q+ chromosome in the acute myelogenous leukemia 8;21 translocation: evidence that c-mos is not translocated.  

PubMed Central

Acute myelogenous leukemia (AML), subgroup M2, is associated with a nonrandom chromosomal translocation, t(8;21)(q22,q22). The oncogene c-mos also has been localized to the q22 band on chromosome 8. There is also evidence that genes on chromosome 21 may be important in the development of leukemia. To determine whether the c-mos oncogene has been translocated in AML-M2 with this translocation and to isolate DNA sequences and genes from these two chromosomes that may be important in malignancy, we constructed somatic cell hybrids between a Chinese hamster ovary cell (CHO) mutant defective in glycine metabolism and myeloblasts with an 8;21 translocation from a patient with AML. We isolated the 21q+ chromosome of this translocation in a somatic cell hybrid and showed that the c-mos oncogene had not been translocated to chromosome 21, ruling out the possibility that translocation of c-mos to chromosome 21 is necessary for development of AML-M2. In addition, there was no detectable rearrangement of the c-mos locus within a 12.4-kilobase region surrounding the gene, indicating that rearrangement of the coding region of the gene itself or alteration of proximal 5' or 3' flanking sequences is not involved. We used this hybrid to determine whether specific DNA sequences and biochemical markers from chromosomes 8 and 21 had been translocated in this case. Images

Drabkin, H A; Diaz, M; Bradley, C M; Le Beau, M M; Rowley, J D; Patterson, D

1985-01-01

412

Voltage-driven translocation of DNA through a high throughput conical solid-state nanopore.  

PubMed

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 (Si(3)N(4)) 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. PMID:23029365

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

2012-09-24

413

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

414

Out of Equilibrium Characteristics of a Forced Translocating Chain through a Nanopore  

NASA Astrophysics Data System (ADS)

Polymer translocation through a nano-pore in a thin membrane is studied using Langevin dynamics simulation with a particular emphasis to explore out of equilibrium characteristics of the translocating chain. We analyze the chain conformations both at the cis and the trans side separately. A detail picture of translocation emerges by monitoring the center of mass of the translocating chain, longitudinal and transverse components of the gyration radii and the end-to-end vector. We observe that polymer configurations at the cis side are distinctly different from those at the trans side. During the translocation, and immediately afterwards, different parts of the chain are characterized by a series of effective Flory exponents. We further notice that immediately after the translocation the last set of beads that have just translocated take a relatively compact structure compared to the first set of beads that translocated earlier and the translocation dynamics can be described as a propagating defect. We discuss implications of these results to the theoretical estimates and numerical simulation studies of the translocation exponent reported by various groups.

Binder, Kurt; Bhattacharya, Aniket

2010-03-01

415

All G protein ?? complexes are capable of translocation on receptor activation.  

PubMed

Heterotrimeric G proteins transduce signals sensed by transmembrane G protein coupled receptors (GPCRs). A subfamily of G protein ?? subunit types has been shown to selectively translocate from the plasma membrane to internal membranes on receptor activation. Using 4D imaging we show here that G?? translocation is not restricted to some subunit types but rather all 12 members of the family of mammalian ? subunits are capable of supporting ?? translocation. Translocation kinetics varies widely depending on the specific ? subunit type, with t(1/2) ranging from 10s to many minutes. Using fluorescence complementation, we show that the ? and ? subunits translocate as ?? dimers with kinetics determined by the ? subunit type. The expression patterns of endogenous ? subunit types in HeLa cells, hippocampal neurons and cardiomyocytes are distinctly different. Consistent with these differences, the ?? translocation rates vary widely. ?? translocation rates exhibit the same ? subunit dependent trends regardless of the specific receptor type or cell type showing that the translocation rates are intrinsic to the ? subunit types. ?? complexes with widely different rates of translocation had differential effects on muscarinic stimulation of GIRK channel activity. These results show that G protein ?? translocation is a general response to activation of GPCRs and may play a role in regulating signaling activity. PMID:22538369

Ajith Karunarathne, W K; O'Neill, Patrick R; Martinez-Espinosa, Pedro L; Kalyanaraman, Vani; Gautam, N

2012-04-19

416

Effect of Potassium Deficiency upon Translocation of 14C in Detached Blades of Sugarcane 1  

PubMed Central

The translocation of radioactive photosynthate was studied in blades detached from plants which had been grown in nutrient solution with and without potassium. Basipetal translocation decreased in the blades of plants deprived of potassium, even when deficiency symptoms were not visible. In such slightly potassium-deficient leaves, translocation was decreased in the light but not in the dark. More severe potassium deficiency decreased translocation both in darkness and in light. Potassium deficiency decreased translocation at light intensities giving no difference in rate of photosynthesis between plus and minus potassium leaves and even at light intensities at which there was no net fixation of carbon dioxide. At all levels of deficiency, the relative decrease in translocation was greater than the relative decrease in photosynthesis. Translocation was affected at potassium deficiency levels which had no effect upon photosynthesis. Potassium deficiency decreased translocation relatively more than it decreased moisture content. There was a much better correlation between the decrease in potassium and translocation than between the decrease in moisture and translocation. An experiment with radioactive phosphorus indicated an upset in phosphorylation in the stems of potassium-deficient plants.

Hartt, Constance E.

1970-01-01

417

Effect of Potassium Deficiency upon Translocation of C in Detached Blades of Sugarcane.  

PubMed

The translocation of radioactive photosynthate was studied in blades detached from plants which had been grown in nutrient solution with and without potassium. Basipetal translocation decreased in the blades of plants deprived of potassium, even when deficiency symptoms were not visible. In such slightly potassium-deficient leaves, translocation was decreased in the light but not in the dark. More severe potassium deficiency decreased translocation both in darkness and in light. Potassium deficiency decreased translocation at light intensities giving no difference in rate of photosynthesis between plus and minus potassium leaves and even at light intensities at which there was no net fixation of carbon dioxide. At all levels of deficiency, the relative decrease in translocation was greater than the relative decrease in photosynthesis. Translocation was affected at potassium deficiency levels which had no effect upon photosynthesis.Potassium deficiency decreased translocation relatively more than it decreased moisture content. There was a much better correlation between the decrease in potassium and translocation than between the decrease in moisture and translocation.An experiment with radioactive phosphorus indicated an upset in phosphorylation in the stems of potassium-deficient plants. PMID:16657300

Hartt, C E

1970-02-01

418

The Arabidopsis translocator protein ( At TSPO) is regulated at multiple levels in response to salt stress and perturbations in tetrapyrrole metabolism  

Microsoft Academic Search

Background  The translocator protein 18 kDa (TSPO), previously known as the peripheral-type benzodiazepine receptor (PBR), is important\\u000a for many cellular functions in mammals and bacteria, such as steroid biosynthesis, cellular respiration, cell proliferation,\\u000a apoptosis, immunomodulation, transport of porphyrins and anions. Arabidopsis thaliana contains a single TSPO\\/PBR-related gene with a 40 amino acid N-terminal extension compared to its homologs in bacteria or

Emilia Balsemão-Pires; Yvon Jaillais; Bradley JSC Olson; Leonardo R Andrade; James G Umen; Joanne Chory; Gilberto Sachetto-Martins

2011-01-01

419

Sec61?, a subunit of the Sec61 protein translocation channel at the Endoplasmic Reticulum, is involved in the transport of Gurken to the plasma membrane.  

PubMed Central

Background Protein translocation across the membrane of the Endoplasmic Reticulum (ER) is the first step in the biogenesis of secretory and membrane proteins. Proteins enter the ER by the Sec61 translocon, a proteinaceous channel composed of three subunits, ?, ? and ?. While it is known that Sec61? forms the actual channel, the function of the other two subunits remains to be characterized. Results In the present study we have investigated the function of Sec61? in Drosophila melanogaster. We describe its role in the plasma membrane traffic of Gurken, the ligand for the Epidermal Growth Factor (EGF) receptor in the oocyte. Germline clones of the mutant allele of Sec61? show normal translocation of Gurken into the ER and transport to the Golgi complex, but further traffic to the plasma membrane is impeded. The defect in plasma membrane traffic due to absence of Sec61? is specific for Gurken and is not due to a general trafficking defect. Conclusion Based on our study we conclude that Sec61?, which is part of the ER protein translocation channel affects a post-ER step during Gurken trafficking to the plasma membrane. We propose an additional role of Sec61? beyond protein translocation into the ER.

Kelkar, Anshuman; Dobberstein, Bernhard

2009-01-01

420

Attenuation of half-tone background detail from fingermark images using digital image processing techniques  

Microsoft Academic Search

Frequency domain processing of fingermark images is valuable for reducing interfering periodic backgrounds. The success of the processing and the quality of the results depend upon a number of factors including structure and chosen processing method. This paper shows that in some circumstances it is possible to determine the most appropriate frequency domain filter for attenuation of interfering backgrounds using

Pacila M. Fabrizi; Simon K. Bramble; G. R. Jackson

1995-01-01

421

Recognizing foreground-background interaction  

NASA Astrophysics Data System (ADS)

Can the background affect a foreground target in distant, low-quality imagery? If it does, it might occur in our mind, or perhaps it may represent a snapshot of our early vision. An affirmative answer, one way or another, may affect our current understanding of this phenomena and potentially for related applications. How can we be sure about this in the psycho-physical sense? We begin with the physiology of our brain's homeostasis, of which an isothermal equil