Characterization of the internal IRES element of the zebrafish connexin55.5 reveals functional implication of the polypyrimidine tract binding protein

<p>Abstract</p> <p>Background</p> <p>Connexin55.5 (Cx55.5) is a gap junction protein with horizontal cell-restricted expression in zebrafish accumulating at dendritic sites within the receptor-horizontal cell complex in form of hemichannels where light-dependent plasticity occurs. This connexin is the first example of a gap junction protein processed to form two protein isoforms from a monocistronic message by an IRES mediated process. The nuclear occurrence of a carboxy-terminal fragment of this protein provides evidence that this gap junction protein may participate in a putative cytoplasmic to nuclear signal transfer.</p> <p>Results</p> <p>We characterized the IRES element of Cx55.5 in terms of sequence elements necessary for its activity and protein factor(s), which may play a role for its function. Two stretches of polypyrimidine tracts designated PPT1 and PPT2 which influence the IRES activity of this neuronal gap junction protein were identified. Selective deletion of PPT1 results in an appreciable decrease of the IRES activity, while the deletion of PPT2 results in a complete loss. RNA-EMSA and UV-cross linking experiments showed that protein complexes bind to this IRES element, of which the polypyrimidine tract binding protein (PTB) was identified as one of the interacting partners with influence on IRES activity. These results indicate that PTB conveys a role in the regulation of the IRES activity of Cx55.5.</p> <p>Conclusion</p> <p>Our findings indicate that the activity of the IRES element of the neuronal gap junction protein Cx55.5 is subject of regulation through flanking polypyrimidine tracts, and that the non-canonical trans-activation factor PTB plays an essential role in this process. This observation is of considerable importance and may provide initial insight into molecular-functional relationships of electrical coupling in horizontal cells.</p

Power Dynamics of State Institutions in Pakistan, Discourse Analysis of Bureaucracy and the Legislature (1971-1977)

The Parliament of Pakistan from 1971 to 1977 was the first Parliament of present day Pakistan and the first bicameral Parliament in the history of the state. Therefore this Parliament seemed to have developed as a powerful institution in contrast to other institutions of the state. The mutual confrontation between the two major institutions of the state namely the bureaucracy and the parliament in order to get thedriving position of the state will be the focus of this study. It will discuss the mutual relationship of the institutions of bureaucracy and the parliament in the presence of more powerful institution of Chief Executive at the time. The paper will try to analyze the influence and powers of the parliament which was apparently strong but in fact was weaker than bureaucracy. The functions of parliamentary institution were highlighted and projected to be stronger than those of bureaucracy but in fact the real functionary was the bureaucracy. The key sources of the paper are the parliamentary debates, reliable works of research, statements of various key players and various documents from the Pakistani, British and US archives.&nbsp

Estimation of volatile organic compounds in farmed and wild rohu, Labeo rohita

Volatile organic compounds in farmed and wild rohu, Labeo rohita, were extracted by Likens-Nickerson concurrent distillation apparatus. The farmed raised rohu of two weight categories designated as FW1 (1001-1200g) and FW2 (501-700g) were procured from the Fish Seed Hatchery, Faisalabad. Concurrently, wild rohu of two weight categories designated as WW1 (1001-1200g) and WW2 (501-700g) were captured with gillnet from the Trimu Head. Quantitative and qualitative estimation was made by gas chromatography. In farmed and wild L. rohita of the weight group FW1 and WW1, 14 and 6 volatile compounds were extracted, respectively. In weight group FW1, six compounds were identified as 3-methyl-1-butanol, 3-hexene-1-ol, heptanal, 3-octanol, decanal and 2-undecanone. In weight group WW1, out of six compounds three were identified as heptanal, 1-octen-3-ol, 2-nonanone. In weight categories FW2 and WW2, 14 and 13 volatile compounds were detected, respectively. In weight category FW2, out of 14 compounds, 3-hexene-1-ol, heptanal, 3-octanol, 2-undecanone and decanal were identified. In weight category WW2, out of 13 compounds, 7 were identified as 3-methyl-1-butanol, 2-heptanone, heptanal, 3-octanol, 2-nonanone, decanal and 2-undecanone. The analysis of variance for retention time and concentration of volatile compounds showed no significant difference (p>0.05). The correlation coefficient between retention time and concentration was significant (p< 0.05)

Movement for the Restoration of Democracy (MRD): Reflection and Resistance against Dictatorial Regime in Punjab

The Movement for Restoration of Democracy (MRD) emerged when General Zia-ul-Haq could not fulfill the promise of conducting elections and prolonged his dictatorial regime instead of fulfilling his promise. He drew his power from a controlled system of government. In those circumstances, the democrats formed an alliance against the martial law administration. They neglected their internal differences and focused on their goal to achieve freedom of expression and liberty which was snubbed by the regime. MRD main demands were the restoration of democracy, under 1973 Constitution, conduction of election and handing over the system of administration to representatives of people. MRD continued struggled till the end of dictatorial regime in 1988

EUV Emission and Scattered Light Diagnostics of Equatorial Coronal Holes as Seen by Hinode/EIS

Spectroscopic diagnostics of solar coronal plasmas critically depends on the uncertainty in the measured line intensities. One of the main sources of uncertainty is instrumental scattered light, which is potentially most important in low-brightness areas. In the solar corona, such areas include polar and equatorial coronal holes, which are the source regions of the solar wind; instrument-scattered light must thus pose a significant obstacle to studies of the source regions of the solar wind. In this paper we investigate the importance of instrument-scattered light on observations of equatorial coronal holes made by the Hinode/EIS spectrometer in two different phases of the solar cycle. We find that the instrument-scattered light is significant at all temperatures, and in both regions it amounts to approximately 10% of the average intensity of the neighboring quiet Sun regions. Such contribution dominates the measured intensity for spectral lines formed at temperatures larger than Log T = 6.15 K, and has deep implications for spectroscopic diagnostics of equatorial coronal hole plasmas and studies of the source regions of a large portion of the solar wind which reaches Earth. Our results suggest that the high temperature tail of in the coronal hole plasma distribution with temperature, however small, is an artifact due to the presence of scattered light.Comment: 11 pages, 6 figure

Performance Analysis of Relay-Assisted Device-to-Device Communication

Outage and Success performances of an amplify-and-forward relay-assisted D2D communication system over a κ-μ shadowed fading wireless link are presented here. Co-channel interference (CCI) is assumed to affect the D2D signals at relay and destination nodes. The system is analyzed with two scenarios, namely, with diversity combining and without diversity combining. Selection combining (SC) based diversity scheme is incorporated at the D2D receiver to combat fading conditions. The expressions for success and outage probabilities are presented by using the characteristic function approach. The expressions are functions of path-loss exponents, wireless link length between relay and D2D source node, wireless link length between the receiver node and relay, distances between interferers and the relay node, CCI distances from various devices of the system, fading channel. The numerical analysis for various scenarios is presented and analyzed

Performance Analysis of Relay-Assisted Device-to-Device Communication

Outage and Success performances of an amplify-and-forward relay-assisted D2D communication system over a κ-μ shadowed fading wireless link are presented here. Co-channel interference (CCI) is assumed to affect the D2D signals at relay and destination nodes. The system is analyzed with two scenarios, namely, with diversity combining and without diversity combining. Selection combining (SC) based diversity scheme is incorporated at the D2D receiver to combat fading conditions. The expressions for success and outage probabilities are presented by using the characteristic function approach. The expressions are functions of path-loss exponents, wireless link length between relay and D2D source node, wireless link length between the receiver node and relay, distances between interferers and the relay node, CCI distances from various devices of the system, fading channel. The numerical analysis for various scenarios is presented and analyzed

IRES-mediated translation of the carboxy-terminal domain of the horizontal cell specific connexin Cx55.5 in vivo and in vitro

<p>Abstract</p> <p>Background</p> <p>Changes of the interneuronal coupling mediated by electrical synapse proteins in response to light adaptation and receptive field shaping are a paramount feature in the photoreceptor/horizontal cell/bipolar cell (PRC/HC/BPC) complex of the outer retina. The regulation of these processes is not fully understood at the molecular level but they may require information transfer to the nucleus by locally generated messengers. Electrical synapse proteins may comprise a feasible molecular determinant in such an information-laden signalling pathway.</p> <p>Results</p> <p>Connexin55.5 (Cx55.5) is a connexin with horizontal cell-restricted expression in zebrafish accumulating at dendritic sites within the PRC/HC/BPC complex in form of hemichannels where light-dependent plasticity occurs. Here we provide evidence for the generation of a carboxy-terminal domain of Cx55.5. The protein product is translated from the Cx55.5 mRNA by internal translation initiation from an in-frame ATG codon involving a putative internal ribosome entry site (IRES) element localized in the coding region of Cx55.5. This protein product resembling an 11 kDa domain of Cx55.5 is partially located in the nucleus <it>in vivo </it>and <it>in vitro</it>.</p> <p>Conclusion</p> <p>Our results demonstrate the generation of a second protein from the coding region of Cx55.5 by an IRES mediated process. The nuclear occurrence of a fraction of this protein provides first evidence that this electrical synapse protein may participate in a putative cytoplasmic to nuclear signal transfer. This suggests that Cx55.5 could be involved in gene regulation making structural plasticity at the PRC/HC/BPC complex feasible.</p

Efectos inducidos por el hábitat sobre mutaciones y perfil de ácidos grasos en carpas mrigala que habitan en el fondo del río Chenab

Fish from the river Chenab were analyzed for DNA damage by the Comet and Micronucleus assays. The fatty acid profile was determined by gas chromatography using a Flame Ionization Detector. Atomic absorption spectrophotometry showed significant (p < 0.05) levels of contamination due to Cd, Hg, Cu, Mn, Zn, Pb, Cr, Sn and phenols in the fish habitat. The Comet assay revealed significant (p < 0.05) DNA damage in Cirrhinus mrigala of 37.29±2.51%, 34.96±2.53% and 38.80±2.42% in the comet tail, in the tail moment of 23.48±3.90, 19.78±4.26 and 14.30±1.82, in the olive moment of 16.22±2.04, 13.83±1.96 10.99±0.90, respectively, from three experimental sites. The micronucleus assay showed a high frequency of single micronucleus induction of 44.80±3.73, double induction of 06.20±0.97 and nuclear abnormalities of 09.60±1.72, as calculated in a thousand cells. C8:0, C12:0, C20:0, C16:1(n-7), C16:1(n-9), C20:1(n-9), C18:2(n-6), C18:4(n-3), C20:5(n-3), C22:4(n-6) fatty acids were found missing in the fish with a higher intensity of DNA damage but were found in optimal amounts both in farmed and wild fish from non polluted habitats. A highly significant (p < 0.01) correlation was also found in saturated, unsaturated fatty acids and DNA damage and habitat. The present study revealed that the habitat of even lower intensity pollutions not only induce DNA damage but also confiscate essential fatty acids of the omega series and reduce the amount of unsaturated fatty acids for which fish is preferred over other animals.Los daños en el ADN de los peces del río Chenab se analizaron mediante la técnica del “ensayo del cometa” y el ensayo de micronúcleos. El perfil de ácidos grasos se determinó mediante cromatografía de gases con detector de ionización de llama. La espectrofotometría de absorción atómica mostró diferencias significativas (p < 0.05) de los niveles de contaminación por Cd, Hg, Cu, Mn, Zn, Pb, Cr, Sn y fenoles en el hábitat de los peces. El ensayo del cometa mostró daños significativos (p < 0,05) en el ADN de las carpas mrigala de tres sitios experimentales: 37,29±2,51%, 34,96±2,53 y 38,80±2,42% del ADN en la cola del cometa, momento de la cola con 23,48±3,90, 19,78±4,26 y 14,30±1,82% y cola media con 16,22±2,04, 13,83±1,96 10,99±0,90. Los ensayos de micronúcleos mostraron una alta frecuencia de inducción de micronúcleos como única 44,80±3,73, 06,20±0,97 y doble anomalías nucleares 09,60±1,72 calculados en miles de células. C8:0, C12:0, C20:0, C16:1(n-7), C16:1 (n-9), C20:1(n-9), C18:2(n-6), C18:4(n-3), C20:5(n-3) y C22:4(n-6) se mostraron como ácidos grasos que faltan en el pescado que tiene una mayor intensidad de daño en el ADN, aunque se encuentran en cantidades óptimas, tanto en los peces de piscifactoría como en los salvajes donde no hay hábitats contaminados. Se encontró una correlación altamente significativa (p < 0,01) también en ácidos saturados, ácidos grasos insaturados, daño del ADN y hábitat. El presente estudio reveló que la intensidad de la contaminación del hábitat aún en la más baja no sólo induce daño en el ADN, sino también en la composición de los ácidos grasos de la serie omega y de los ácidos grasos insaturados, para los que se prefiere ingerir pescado a otros animales