Search

Your search keyword '"Ray, D. S."' showing total 218 results
Start Over Author "Ray, D. S."
218 results on '"Ray, D. S."'

1. Bohr Sommerfeld quantisation and molecular potentials

Author

Bhattacharjee, Shayak, Ray, D. S., and Bhattacharjee, J. K.

Subjects
Mathematical Physics
Abstract

We use the Bohr Sommerfeld quantization rule along with a perturbative evaluation of the action intergral to find exact energy levels for the P\"oschl-Teller potential (both hyperbolic and trigonometric forms), the Morse potential, and the Rosen Morse potential. Combining perturbation theory with the simplest asymptotic evaluation of the action integral allows us to obtain all the energy levels of the Lennard-Jones potential with an accuracy greater than 0.1 per cent and serves to confirm that the perturbation results for P\"oschl-Teller and Morse Potentials are exact., Comment: Use of perturbation theory and Bohr Sommerfeld quantisation to find energy eigenvalues of some potentials; Journal of Mathematical Chemistry online first Oct. 18, 2011

Published
2011

3. A semiclassical theory of quantum noise in open chaotic systems

Author

Bag, B. C., Chaudhuri, S., Chaudhuri, J. Ray, and Ray, D. S.

Subjects
Nonlinear Sciences - Chaotic Dynamics, Condensed Matter - Statistical Mechanics, Quantum Physics
Abstract

We consider the quantum evolution of classically chaotic systems in contact with surroundings. Based on $\hbar$-scaling of an equation for time evolution of the Wigner's quasi-probability distribution function in presence of dissipation and thermal diffusion we derive a semiclassical equation for quantum fluctuations. This identifies an early regime of evolution dominated by fluctuations in the curvature of the potential due to classical chaos and dissipation. A stochastic treatment of this classical fluctuations leads us to a Fokker-Planck equation which is reminiscent of Kramers' equation for thermally activated processes. This reveals an interplay of three aspects of evolution of quantum noise in weakly dissipative open systems; the reversible Liouville flow, the irreversible chaotic diffusion which is characteristic of the system itself, and irreversible dissipation induced by the external reservoir. It has been demonstrated that in the dissipation-free case a competition between Liouville flow in the contracting direction of phase space and chaotic diffusion sets a critical width in the Wigner function for quantum fluctuations. We also show how the initial quantum noise gets amplified by classical chaos and ultimately equilibrated under the influence of dissipation. We establish that there exists a critical limit to the expansion of phase space. The limit is determined by chaotic diffusion and dissipation. Making use of appropriate quantum-classical correspondence we verify the semiclassical analysis by the fully quantum simulation in a chaotic quartic oscillator., Comment: Plain Latex, 27 pages, 6 ps figure, To appear in Physica D

Published
1998
Full Text
View/download PDF

4. Theory of Adiabatic fluctuations : third-order noise

Author

Banik, S. K., Chaudhuri, J. R., and Ray, D. S.

Subjects
Condensed Matter - Statistical Mechanics
Abstract

We consider the response of a dynamical system driven by external adiabatic fluctuations. Based on the `adiabatic following approximation' we have made a systematic separation of time-scales to carry out an expansion in $\alpha |\mu|^{-1}$, where $\alpha$ is the strength of fluctuations and $|\mu|$ is the damping rate. We show that probability distribution functions obey the differential equations of motion which contain third order terms (beyond the usual Fokker-Planck terms) leading to non-Gaussian noise. The problem of adiabatic fluctuations in velocity space which is the counterpart of Brownian motion for fast fluctuations, has been solved exactly. The characteristic function and the associated probability distribution function are shown to be of stable form. The linear dissipation leads to a steady state which is stable and the variances and higher moments are shown to be finite., Comment: Plain Latex, no figures, 28 pages; to appear in J. Phys. A

Published
1998
Full Text
View/download PDF

5. Linear systems with adiabatic fluctuations

Author

Banik, S. K. and Ray, D. S.

Subjects
Condensed Matter - Statistical Mechanics
Abstract

We consider a dynamical system subjected to weak but adiabatically slow fluctuations of external origin. Based on the ``adiabatic following'' approximation we carry out an expansion in \alpha/|\mu|, where \alpha is the strength of fluctuations and 1/|\mu| refers to the time scale of evolution of the unperturbed system to obtain a linear differential equation for the average solution. The theory is applied to the problems of a damped harmonic oscillator and diffusion in a turbulent fluid. The result is the realization of `renormalized' diffusion constant or damping constant for the respective problems. The applicability of the method has been critically analyzed., Comment: Plain Latex, no figure, 21 pages

Published
1998
Full Text
View/download PDF

12. Instability and pattern formation in reaction-diffusion systems: A higher order analysis.

Author

Riaz, Syed Shahed, Sharma, Rahul, Bhattacharyya, S. P., and Ray, D. S.

Subjects
REACTION-diffusion equations, NONLINEAR theories, CHEMICAL reactions, SOLUTION (Chemistry), MOLECULAR association
Abstract

We analyze the condition for instability and pattern formation in reaction-diffusion systems beyond the usual linear regime. The approach is based on taking into account perturbations of higher orders. Our analysis reveals that nonlinearity present in the system can be instrumental in determining the stability of a system, even to the extent of destabilizing one in a linearly stable parameter regime. The analysis is also successful to account for the observed effect of additive noise in modifying the instability threshold of a system. The analytical study is corroborated by numerical simulation in a standard reaction-diffusion system. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

14. TRANSPLANTATION CLINICAL 1

Author

Schachtner, T., primary, Reinke, P., additional, Dorje, C., additional, Mjoen, G., additional, Midtvedt, K., additional, Strom, E. H., additional, Oyen, O., additional, Jenssen, T., additional, Reisaeter, A. V., additional, Smedbraaten, Y. V., additional, Sagedal, S., additional, Fagerland, M. W., additional, Hartmann, A., additional, Thiel, S., additional, Zulkarnaev, A., additional, Vatazin, A., additional, Vincenti, F., additional, Harel, E., additional, Kantor, A., additional, Thurison, T., additional, Hoyer-Hansen, G., additional, Craik, C., additional, Kute, V. B., additional, Shah, P. S., additional, Vanikar, A. V., additional, Modi, P. R., additional, Shah, P. R., additional, Gumber, M. R., additional, Patel, H. V., additional, Engineer, D. P., additional, Shah, V. R., additional, Rizvi, J., additional, Trivedi, H. L., additional, Malheiro, J., additional, Dias, L., additional, Martins, L. S., additional, Fonseca, I., additional, Pedroso, S., additional, Almeida, M., additional, Castro-Henriques, A., additional, Cabrita, A., additional, Costa, C., additional, Ritta, M., additional, Sinesi, F., additional, Sidoti, F., additional, Mantovani, S., additional, Di Nauta, A., additional, Messina, M., additional, Cavallo, R., additional, Verflova, A., additional, Svobodova, E., additional, Slatinska, J., additional, Slavcev, A., additional, Pokorna, E., additional, Viklicky, O., additional, Yagan, J., additional, Chandraker, A., additional, Diena, D., additional, Tognarelli, G., additional, Ranghino, A., additional, Bussolino, S., additional, Fop, F., additional, Segoloni, G. P., additional, Biancone, L., additional, Leone, F., additional, Mauro, M. V., additional, Gigliotti, P., additional, Lofaro, D., additional, Greco, F., additional, Perugini, D., additional, Papalia, T., additional, Perri, A., additional, Vizza, D., additional, Giraldi, C., additional, Bonofilgio, R., additional, Luis-Lima, S., additional, Marrero, D., additional, Gonzalez-Rinne, A., additional, Torres, A., additional, Salido, E., additional, Jimenez-Sosa, A., additional, Aldea-Perona, A., additional, Gonzalez-Posada, J. M., additional, Perez-Tamajon, L., additional, Rodriguez-Hernandez, A., additional, Negrin-Mena, N., additional, Porrini, E., additional, Pihlstrom, H., additional, Dahle, D. O., additional, Holdaas, H., additional, Von Der Lippe, N., additional, Waldum, B., additional, Brekke, F., additional, Amro, A., additional, Os, I., additional, Klin, P., additional, Sanabria, H., additional, Bridoux, P., additional, De Francesco, J., additional, Fortunato, R. M., additional, Raffaele, P., additional, Kong, J., additional, Son, S. H., additional, Kwon, H. Y., additional, Whang, E. J., additional, Choi, W. Y., additional, Yoon, C. S., additional, Thanaraj, V., additional, Theakstone, A., additional, Stopper, K., additional, Ferraro, A., additional, Bhattacharjya, S., additional, Devonald, M., additional, Williams, A., additional, Mella, A., additional, Gallo, E., additional, Di Vico, M. C., additional, Pagani, F., additional, Gai, M., additional, Cho, H. J., additional, Nho, K. W., additional, Park, S.-K., additional, Kim, S. B., additional, Yoshida, K., additional, Ishii, D., additional, Ohyama, T., additional, Kohguchi, D., additional, Takeuchi, Y., additional, Varga, A., additional, Sandor, B., additional, Kalmar-Nagy, K., additional, Toth, A., additional, Toth, K., additional, Szakaly, P., additional, Kildushevsky, A., additional, Fedulkina, V., additional, Kantaria, R., additional, Staeck, O., additional, Halleck, F., additional, Rissling, O., additional, Naik, M., additional, Neumayer, H.-H., additional, Budde, K., additional, Khadzhynov, D., additional, Bhadauria, D., additional, Kaul, A., additional, Prasad, N., additional, Sharma, R. K., additional, Sezer, S., additional, Bal, Z., additional, Erkmen Uyar, M., additional, Guliyev, O., additional, Erdemir, B., additional, Colak, T., additional, Ozdemir, N., additional, Haberal, M., additional, Caliskan, Y., additional, Yazici, H., additional, Artan, A. S., additional, Oto, O. A., additional, Aysuna, N., additional, Bozfakioglu, S., additional, Turkmen, A., additional, Yildiz, A., additional, Sever, M. S., additional, Yagisawa, T., additional, Nukui, A., additional, Kimura, T., additional, Nannmoku, K., additional, Kurosawa, A., additional, Sakuma, Y., additional, Miki, A., additional, Damiano, F., additional, Ligabue, G., additional, De Biasi, S., additional, Granito, M., additional, Cossarizza, A., additional, Cappelli, G., additional, Henriques, A. C., additional, Davide, J., additional, Von During, M. E., additional, Jenssen, T. G., additional, Bollerslev, J., additional, Godang, K., additional, Asberg, A., additional, Bachelet, T., additional, Martinez, C., additional, Bello, A., additional, Kejji, S., additional, Couzi, L., additional, Guidicelli, G., additional, Lepreux, S., additional, Visentin, J., additional, Congy-Jolivet, N., additional, Rostaing, L., additional, Taupin, J.-L., additional, Kamar, N., additional, Merville, P., additional, Ozdemir, H., additional, Yildirim, S., additional, Tutal, E., additional, Sayin, B., additional, Ozdemir Acar, N., additional, Banasik, M., additional, Boratynska, M., additional, Koscielska-Kasprzak, K., additional, Kaminska, D., additional, Bartoszek, D., additional, Mazanowska, O., additional, Krajewska, M., additional, Zmonarski, S., additional, Chudoba, P., additional, Dawiskiba, T., additional, Protasiewicz, M., additional, Halon, A., additional, Sas, A., additional, Kaminska, M., additional, Klinger, M., additional, Stefanovic, N., additional, Cvetkovic, T., additional, Velickovic - Radovanovic, R., additional, Jevtovic - Stoimenov, T., additional, Vlahovic, P., additional, Rungta, R., additional, Das, P., additional, Ray, D. S., additional, Gupta, S., additional, Kolonko, A., additional, Szotowska, M., additional, Kuczera, P., additional, Chudek, J., additional, Wiecek, A., additional, Sikora-Grabka, E., additional, Adamczak, M., additional, Madej, P., additional, Amanova, A., additional, Kendi Celebi, Z., additional, Bakar, F., additional, Caglayan, M. G., additional, Keven, K., additional, Massimetti, C., additional, Imperato, G., additional, Zampi, G., additional, De Vincenzi, A., additional, Fabbri, G. D. D., additional, Brescia, F., additional, Feriozzi, S., additional, Filipov, J. J., additional, Zlatkov, B. K., additional, Dimitrov, E. P., additional, Svinarov, D. A., additional, Poesen, R., additional, De Vusser, K., additional, Evenepoel, P., additional, Kuypers, D., additional, Naesens, M., additional, Meijers, B., additional, Kocak, H., additional, Yilmaz, V. T., additional, Yilmaz, F., additional, Uslu, H. B., additional, Aliosmanoglu, I., additional, Ermis, H., additional, Dinckan, A., additional, Cetinkaya, R., additional, Ersoy, F. F., additional, Suleymanlar, G., additional, Oliveira, J.-C., additional, Santos, J., additional, Lobato, L., additional, Mendonca, D., additional, Watarai, Y., additional, Yamamoto, T., additional, Tsujita, M., additional, Hiramitsu, T., additional, Goto, N., additional, Narumi, S., additional, Kobayashi, T., additional, Line, P.-D., additional, Housawi, A., additional, House, A., additional, Ng, C., additional, Denesyk, K., additional, Rehman, F., additional, Moist, L., additional, Musetti, C., additional, Battista, M., additional, Izzo, C., additional, Guglielmetti, G., additional, Airoldi, A., additional, Stratta, P., additional, Cena, T., additional, Quaglia, M., additional, Fenoglio, R., additional, Cagna, D., additional, Amoroso, A., additional, Palmisano, A., additional, Degli Antoni, A. M., additional, Vaglio, A., additional, Piotti, G., additional, Cremaschi, E., additional, Buzio, C., additional, Maggiore, U., additional, Lee, M.-C., additional, Hsu, B.-G., additional, Zalamea Jarrin, F., additional, Sanchez Sobrino, B., additional, Lafuente Covarrubias, O., additional, Karsten Alvarez, S., additional, Dominguez Apinaniz, P., additional, Llopez Carratala, R., additional, Portoles Perez, J., additional, Yildirim, T., additional, Yilmaz, R., additional, Turkmen, E., additional, Altindal, M., additional, Arici, M., additional, Altun, B., additional, Erdem, Y., additional, Dounousi, E., additional, Mitsis, M., additional, Naka, K., additional, Pappas, H., additional, Lakkas, L., additional, Harisis, H., additional, Pappas, K., additional, Koutlas, V., additional, Tzalavra, I., additional, Spanos, G., additional, Michalis, L., additional, Siamopoulos, K., additional, Iwabuchi, T., additional, Nanmoku, K., additional, Yasunaru, S., additional, Yoshikawa, M., additional, Kitamura, K., additional, Fuji, H., additional, Fujisawa, M., additional, Nishi, S., additional, Carta, P., additional, Zanazzi, M., additional, Buti, E., additional, Larti, A., additional, Caroti, L., additional, Di Maria, L., additional, Minetti, E. E., additional, Shi, Y., additional, Luo, L., additional, Cai, B., additional, Wang, T., additional, Zou, Y., additional, Wang, L., additional, Kim, Y., additional, Kim, H. S., additional, Choi, B. S., additional, Park, C. W., additional, Yang, C. W., additional, Kim, Y.-S., additional, Chung, B. H., additional, Baek, C. H., additional, Kim, M., additional, Kim, J.-S., additional, Yang, W. S., additional, Han, D. J., additional, Mikolasevic, I., additional, Racki, S., additional, Lukenda, V., additional, Persic, M. P., additional, Colic, M., additional, Devcic, B., additional, Orlic, L., additional, Gurlek Demirci, B., additional, Say N, C. B., additional, Ozdemir Acar, F. N., additional, Vali, S., additional, Ismal, K., additional, Sahay, M., additional, Civiletti, F., additional, Cantaluppi, V., additional, Medica, D., additional, Mazzeo, A. T., additional, Assenzio, B., additional, Mastromauro, I., additional, Deambrosis, I., additional, Giaretta, F., additional, Fanelli, V., additional, Mascia, L., additional, Gkirdis, I., additional, Bechlioulis, A., additional, Evangelou, D., additional, Zarzoulas, F., additional, Kotsia, A., additional, Balafa, O., additional, Tzeltzes, G., additional, Nakas, G., additional, Kalaitzidis, R., additional, Katsouras, C., additional, Uyanik, S., additional, Toprak, S. K., additional, Ilhan, O., additional, Ekmen Uyar, M., additional, Hernandez Vargas, H., additional, Artamendi Larranaga, M., additional, Ramalle Gomara, E., additional, Gil Catalinas, F., additional, Bello Ovalle, A., additional, Pimentel Guzman, G., additional, Coloma Lopez, A., additional, Sierra Carpio, M., additional, Gil Paraiso, A., additional, Dall Anesse, C., additional, Beired Val, I., additional, Huarte Loza, E., additional, Choy, B. Y., additional, Kwan, L., additional, Mok, M., additional, Chan, T. M., additional, Yamakawa, T., additional, Kobayashi, A., additional, Yamamoto, I., additional, Mafune, A., additional, Nakada, Y., additional, Tannno, Y., additional, Tsuboi, N., additional, Yamamoto, H., additional, Yokoyama, K., additional, Ohkido, I., additional, Yokoo, T., additional, Luque, Y., additional, Anglicheau, D., additional, Rabant, M., additional, Clement, R., additional, Kreis, H., additional, Sartorius, A., additional, Noel, L.-H., additional, Timsit, M.-O., additional, Legendre, C., additional, Rancic, N., additional, Vavic, N., additional, Dragojevic-Simic, V., additional, Katic, J., additional, Jacimovic, N., additional, Kovacevic, A., additional, Mikov, M., additional, Veldhuijzen, N. M. H., additional, Rookmaaker, M. B., additional, Van Zuilen, A. D., additional, Nquyen, T. Q., additional, Boer, W. H., additional, Sahtout, W., additional, Ghezaiel, H., additional, Azzebi, A., additional, Ben Abdelkrim, S., additional, Guedri, Y., additional, Mrabet, S., additional, Nouira, S., additional, Ferdaws, S., additional, Amor, S., additional, Belarbia, A., additional, Zellama, D., additional, Mokni, M., additional, Achour, A., additional, Parikova, A., additional, Hanzal, V., additional, Fronek, J., additional, Orandi, B. J., additional, James, N. T., additional, Montgomery, R. A., additional, Desai, N. M., additional, Segev, D. L., additional, Fontana, F., additional, Ballestri, M., additional, and Magistroni, R., additional

Published
2014
Full Text
View/download PDF

15. Transplantation - clinical studies II

Author

Marques, I. B., primary, Silva, R. d. M., additional, Moraes, C. E., additional, Azevedo, L. S., additional, Nahas, W. C., additional, David-Neto, E., additional, Furmanczyk-Zawiska, A., additional, Baczkowska, T., additional, Chmura, A., additional, Szmidt, J., additional, Durlik, M., additional, Joslin, J., additional, Blaker, P., additional, White, B., additional, Marinaki, A., additional, Sanderson, J., additional, Goldsmith, D. J., additional, Medani, S., additional, Traynor, C., additional, Mohan, P., additional, Little, D., additional, Conlon, P., additional, Molina, M., additional, Gonzalez, E., additional, Gutierrez, E., additional, Sevillano, A., additional, Polanco, N., additional, Morales, E., additional, Hernandez, A., additional, Praga, M., additional, Morales, J. M., additional, Andres, A., additional, Park, S. J., additional, Kim, T. H., additional, Kim, Y. W., additional, Kim, Y. H., additional, Kang, S. W., additional, Kujawa-Szewieczek, A., additional, Szotowska, M., additional, Kuczera, P., additional, Chudek, J., additional, Wiecek, A., additional, Kolonko, A., additional, Mahrova, A., additional, Svagrova, K., additional, Bunc, V., additional, Stollova, M., additional, Teplan, V., additional, Hundt, F., additional, van Heteren, P., additional, Woitas, R., additional, Cavallo, M. C., additional, Sepe, V., additional, Conte, F., additional, Albrizio, P., additional, Bottazzi, A., additional, Geraci, P. M., additional, Alpay, N., additional, Gumber, M. R., additional, Kute, V. B., additional, Vanikar, A. V., additional, Patel, H. V., additional, Shah, P. R., additional, Engineer, D. P., additional, Trivedi, H. L., additional, Golebiewska, J. E., additional, Debska-Slizien, A., additional, Rutkowski, B., additional, Matias, P., additional, Martins, A. R., additional, Raposo, L., additional, Jorge, C., additional, Weigert, A., additional, Birne, R., additional, Bruges, M., additional, Adragao, T., additional, Almeida, M., additional, Mendes, M., additional, Machado, D., additional, Masin-Spasovska, J., additional, Dohcev, S., additional, Stankov, O., additional, Stavridis, S., additional, Saidi, S., additional, Dejanova, B., additional, Rambabova-Busletic, I., additional, Dejanov, P., additional, Spasovski, G., additional, Nho, K. W., additional, Han, D. J., additional, Park, S.-K., additional, Kim, S. B., additional, Fenoglio, R., additional, Lazzarich, E. E., additional, Cagna, D., additional, Cena, T., additional, Conti, N., additional, Quaglia, M., additional, Radin, E., additional, Izzo, C., additional, Stratta, P., additional, Oh, I. H., additional, Park, J.-S., additional, Lee, C. H., additional, Kang, C. M., additional, Kim, G.-H., additional, Leone, F., additional, Lofaro, D., additional, Gigliotti, P., additional, Lupinacci, S., additional, Toteda, P., additional, Vizza, D., additional, Perri, A., additional, Papalia, T., additional, Bonofiglio, R., additional, di Loreto, P., additional, de Silvestro, L., additional, Montanaro, D., additional, Martino, F., additional, Sandrini, S., additional, Minetti, E., additional, Cabiddu, G., additional, Yildirim, T., additional, Yilmaz, R., additional, Turkmen, E., additional, Abudalal, A., additional, Altindal, M., additional, Ertoy-Baydar, D., additional, Erdem, Y., additional, Panuccio, V., additional, Tripepi, R., additional, Parlongo, G., additional, Versace, M. C., additional, Politi, R., additional, Zoccali, C., additional, Mallamaci, F., additional, Porrini, E., additional, Silva, I., additional, Diaz, J., additional, Ibernon, M., additional, Moreso, F., additional, Benitez, R., additional, Delgado Mallen, P., additional, Osorio, J., additional, Lauzurica, R., additional, Torres, A., additional, Ersoy, A., additional, Koca, N., additional, Gullu Koca, T., additional, Kirhan, E., additional, Sarandol, E., additional, Ersoy, C., additional, Dirican, M., additional, Milne, J., additional, Suter, V., additional, Mikhail, A., additional, Akalin, H., additional, Dizdar, O., additional, Pascual, J., additional, Torio, A., additional, Garcia, C., additional, Hernandez, J., additional, Perez-Saez, M. J., additional, Mir, M., additional, Anna, F., additional, Crespo, M., additional, Carta, P., additional, Zanazzi, M., additional, Antognoli, G., additional, Di Maria, L., additional, Caroti, L., additional, Ray, D. S., additional, Mukherjee, K., additional, Bohidar, N. P., additional, Pattanaik, A., additional, Das, P., additional, Thukral, S., additional, Kimura, T., additional, Yagisawa, T., additional, Ishikawa, N., additional, Sakuma, Y., additional, Fujiwara, T., additional, Nukui, A., additional, Gavela, E. E., additional, Sancho, A. A., additional, Kanter, J. J., additional, Avila, A. A., additional, Beltran, S. S., additional, Pallardo, L. L., additional, Dawoud, F. G., additional, Aithal, V., additional, Majernikova, M., additional, Rosenberger, J., additional, Prihodova, L., additional, Nagyova, I., additional, Jarcuskova, M., additional, Roland, R., additional, Groothoff, J. W., additional, van Dijk, J. P., additional, van Agteren, M., additional, de Weerd, A., additional, van de Wetering, J., additional, IJzermans, J., additional, Betjes, M., additional, Weimar, W., additional, Popoola, J., additional, Reed, A., additional, Tavarro, R., additional, Chryssanthopoulou, C., additional, MacPhee, I., additional, Mayor, M., additional, Franco, S., additional, Jara, P., additional, Ayala, R., additional, Orue, M. G., additional, Martinez, A., additional, Martinez, M., additional, Wasmouth, N., additional, Arik, G., additional, Yasar, A., additional, Yilmaz, S., additional, Arici, M., additional, Bihari Bansal, S., additional, Pokhariyal, S., additional, Jain, S., additional, Sethi, S., additional, Ahlawat, R., additional, Kher, V., additional, Martins, L. S., additional, Aguiar, P., additional, Dias, L., additional, Fonseca, I., additional, Henriques, A. C., additional, Cabrita, A., additional, Davide, J., additional, Sparkes, T. M., additional, Trofe-Clark, J., additional, Reese, P. P., additional, Jakobowski, D., additional, Goral, S., additional, Doll, S. L., additional, Abt, P. L., additional, Sawinski, D., additional, MBloom, R. D., additional, Knap, B., additional, Lukac, J., additional, Lukin, M., additional, Majcen, I., additional, Pavlovec, F., additional, Kandus, A., additional, Bren, A. F., additional, Kong, J. M., additional, Jeong, J. H., additional, Ahn, J., additional, Lee, D. R., additional, Son, S. H., additional, Kim, B. C., additional, Choi, W. Y., additional, Whang, E. J., additional, Czajka, B., additional, Malgorzewicz, S., additional, Panizo, N., additional, Rengel, M. A., additional, Vega, A., additional, Abad, S., additional, Tana, L., additional, Arroyo, D., additional, Rodriguez-Ferrero, M., additional, Perez de Jose, A., additional, Lopez-Gomez, J. M., additional, Koutroutsos, K., additional, Sackey, J., additional, Paolini, L., additional, Ramkhelawon, R., additional, Chowrimootoo, M., additional, Whelan, D., additional, Slatinska, J., additional, Honsova, E., additional, Wohlfahrtova, M., additional, Slimackova, E., additional, Rajnochova, S. B., additional, Viklicky, O., additional, Yankovoy, A., additional, Smith, I. S. J., additional, Wylie, E., additional, Ruiz-Esteban, P., additional, Lopez, V., additional, Garcia-Frias, P., additional, Cabello, M., additional, Gonzalez-Molina, M., additional, Vozmediano, C., additional, Hernandez, D., additional, Pavlovic, J., additional, Radivojevic, D., additional, Lezaic, V., additional, Simic-Ogrizovic, S., additional, Lausevic, M., additional, Naumovic, R., additional, Sakhuja, V., additional, Gundlapalli, S., additional, Rathi, M., additional, Jha, V., additional, Kohli, H. S., additional, Sharma, A., additional, Minz, M., additional, Nimgirova, A., additional, Esayan, A., additional, Kayukov, I., additional, Zuyeva, E., additional, Bilen, Y., additional, Cankaya, E., additional, Keles, M., additional, Gulcan, E., additional, Turkeli, M., additional, Albayrak, B., additional, Uyanik, A., additional, Yildirim, R., additional, Molitor, N., additional, Praktiknjo, M., additional, Abeygunaratne, T. N., additional, Balasubramanian, S., additional, Baker, R., additional, Nicholson, T., additional, Toprak, O., additional, Sari, Y., additional, Keceli, S., additional, Kurt, H., additional, Rocha, A., additional, Malheiro, J., additional, Pedroso, S., additional, Henriques, A., additional, Nihei, C., additional, Bacelar Marques, I., additional, Seguro, C. A., additional, Mate, G., additional, Martin, N., additional, Colon, L., additional, Casellas, L., additional, Garangou, D., additional, de la Torre, M., additional, Torguet, P., additional, Garcia, I., additional, Calabia, J., additional, Valles, M., additional, Pruthi, R., additional, Calestani, M., additional, Leydon, G., additional, Ravanan, R., additional, Roderick, P., additional, Korkmaz, S., additional, and Gulten, S., additional

Published
2013
Full Text
View/download PDF

16. Time-dependent perturbation theory in quantum mechanics and the renormalization group.

Author

Bhattacharj, J. K. and Ray, D. S.

Subjects
*TIME-dependent perturbation theory, *QUANTUM mechanics, *RENORMALIZATION group, *QUANTUM field theory, *RESONANCE
Abstract

Time-dependent perturbation theory in quantum mechanics is divergent at long times when the perturbation induces a resonance between two eigenstates of the unperturbed Hamiltonian. Divergences in perturbation theory are also common in quantum field theory and in critical phenomena. The renormalization group (RG) was designed to deal with these divergences. In the last two decades, this procedure has been extended to dynamical systems where the perturbation theory diverges in the long-time limit. In this article, we first review the connection between RG in the context of field theory and RG in the context of dynamical systems. We then show that the long-time divergence in the resonant situation in the time-dependent perturbation theory in quantum mechanics can be removed by using a RG-aided calculational scheme. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

27. The Crithidia fasciculata RNH1 gene encodes both nuclear and mitochondrial isoforms of RNase H.

Author

Engel, M L, Hines, J C, and Ray, D S

Abstract

The Crithidia fasciculata RNH1 gene encodes an RNase H, an enzyme that specifically degrades the RNA strand of RNA-DNA hybrids. The RNH1 gene is contained within an open reading frame (ORF) predicted to encode a protein of 53.7 kDa. Previous work has shown that RNH1 expresses two proteins: a 38 kDa protein and a 45 kDa protein which is enriched in kinetoplast extracts. Epitope tagging of the C-terminus of the RNH1 gene results in localization of the protein to both the kinetoplast and the nucleus. Translation of the ORF beginning at the second in-frame methionine codon predicts a protein of 38 kDa. Insertion of two tandem stop codons between the first ATG codon and the second in-frame ATG codon of the ORF results in expression of only the 38 kDa protein and the protein localizes specifically to the nucleus. Mutation of the second methionine codon to a valine codon prevents expression of the 38 kDa protein and results in exclusive production of the 45 kDa protein and localization of the protein only in the kinetoplast. These results suggest that the kinetoplast enzyme results from processing of the full-length 53.7 kDa protein. The nuclear enzyme appears to result from translation initiation at the second in-frame ATG codon. This is the first example in trypanosomatids of the production of nuclear and mitochondrial isoforms of a protein from a single gene and is the only eukaryotic gene in the RNase HI gene family shown to encode a mitochondrial RNase H.

Published
2001
Full Text
View/download PDF

30. Identification of cis and trans elements involved in the cell cycle regulation of multiple genes in Crithidia fasciculata.

Author

Mahmood, R, Hines, J C, and Ray, D S

Abstract

Transcripts of several DNA replication genes, including the RPA1 and TOP2 genes, encoding the large subunit of nuclear replication protein A and the kinetoplast topoisomerase II, accumulate periodically during the cell cycle in the trypanosomatid Crithidia fasciculata. An octamer consensus sequence, CAUAGAAG, present in the 5' untranslated regions (UTR) of these mRNAs is required for periodic accumulation of the TOP2 and RPA1 transcripts and also for binding of a nuclear factor(s) to the 5' UTR RNAs of these genes. We show here that insertion of multiple (six) copies of this octamer sequence (6x octamer) into the 5' UTR of a reporter gene confers periodic accumulation on its transcript. Competition experiments and UV cross-linking studies show that the 6x octamer RNA and TOP2 5' UTR RNA bind to the same nuclear factor(s). Single-nucleotide substitutions in the 6x octamer that abolish the RNA gel shift also prevent cyclic accumulation of the reporter gene transcript. A protein termed cycling element binding protein, purified by affinity chromatography using 6x octamer RNA as a ligand, binds to RNAs containing wild-type octamers and not to those with mutant octamers. These results define a small sequence element in C. fasciculata mRNAs required for their cell cycle regulation and report the identification and purification of a putative regulatory protein that binds specifically to these elements.

Published
1999

32. Replication of the plasmid pBR322 under the control of a cloned replication origin from the single-stranded DNA phage M13.

Author

Cleary, J M and Ray, D S

Abstract

The replication origins of viral and complementary strands of bacteriophage M13 DNA are contained within a 507-nucleotide intergenic region of the viral genome. Chimeric plasmids have been constructed by inserting restriction endonuclease fragments of the M13 intergenic region into the plasmid pBR322. Replication of these hybrid plasmids, under conditions not permissive for the plasmid replicon, depends on specific segments of the M13 origin region and on the presence of M13 helper virus. Thus M13-infected polA- Escherichia coli can be transformed to ampicillin resistance by hybrid plasmids that have a functional M13 origin. Cells transformed to drug resistance by plasmids bearing M13 origin sequences contain the duplex chimeric DNA at high copy number but do not accumulate significant amounts of single-stranded plasmid DNA. Rare transducing phages carrying single-stranded chimeric DNA are produced and can be detected by their ability to transduce cells to ampicillin resistance. Plasmids containing a 270-nucleotide fragment from the gene II-proximal half of the intergenic region produce transformants at high frequency under nonpermissive conditions. A central Hae III fragment, Hae III-G, containing the nucleotide sequence coding for the RNA primer for the complementary strand and the nicking site for gene II protein, is sufficient for plasmid replication in M13-infected polA- cells but not for high frequency transformation. Additional sequence information on the gene II side of the Hae III-G fragment is necessary for efficient transformation by the plasmid DNA.

Published
1980
Full Text
View/download PDF

33. Degradation of the viral strand of phiX174 parental replicative-form DNA in a rep- host

Author

Bowman, K L and Ray, D S

Abstract

A progressive degradation of the parental viral strand label is observed upon infection of a Rep- mutant of Escherichia coli by 32P-labeled phiX174. Very little parental label remains in the RF (replicative form) by 47 min after infection. Concomitant with this degradation, replicative intermediates are formed which sediment at 21s, the rate of RF I (supercoiled-closed circular DNA), in a neutral sucrose gradient but which denature and sediment in alkaline gradients as single strands of unit size and larger. These denaturable 21s replicative intermediates have been shown previously to be RF molecules containing an elongated viral strand. Addition of chloramphenicol at 7 min after infection at 30 mug/ml, a concentration sufficient to block RF leads to SS (single strand) synthesis but not RF leads to RF synthesis in a wild-type host cell, reduced the amount of viral strand elongation but did not prevent viral strand degradation. The addition of chloramphenicol at 150 mug/ml at 7 min after infection totally prevents both the degradation of the parental label and the formation of the replicative intermediates with elongated tails. We infer that degradation of the viral strand requires the gene A-mediated nicking of the viral strand but not the concomitant elongation of the viral strand.

Published
1975
Full Text
View/download PDF

34. Replication of bacteriophage M13 IX. Requirement of the Escherichia coli dnaG function for M13 duplex DNA replication

Author

Ray, D S, Dueber, J, and Suggs, S

Abstract

Temperature-shift experiments with an Escherichia coli dnaG strain indicate a requirement for the dnaG function for M13 phage production only at an early stage of infection. Mutant cells infected at nonpermissive temperature form the parental RF (SS leads to RF) but do not replicate further. A shift to nonpermissive temperature after infection inhibits RF leads to RF replication but not RF leads to SS synthesis. The synthesis of both strands of the duplex RF was inhibited equally after a temperature shift during RF leads to RF replication. We infer that the dnaG protein is required for M13 production only during RF replication and that it is required for the synthesis of both strands of the RF.

Published
1975
Full Text
View/download PDF

35. Identification of ColE1 DNA sequences that direct single strand-to-double strand conversion by a phi X174 type mechanism.

Author

Nomura, N, Low, R L, and Ray, D S

Abstract

A DNA single-strand initiation sequence, named rriA (called rri-1 previously), was detected in the origin region (Hae II fragment E) of the ColE1 plasmid [Nomura, N. & Ray, D. S. (1980) Proc. Natl. Acad. Sci. USA 77, 6566-6570]. Another site, called rriB, has been found on the opposite strand of Hae II fragment C. Both rriA and rriB (i) direct conversion of chimeric M13 phage single-stranded DNA to parental replicative form DNA in vivo by a rifampicin-resistant mechanism that is dependent on the dnaG and dnaB gene products, (ii) provide effector sites of dATP hydrolysis by primosomal protein n', and (iii) require the same primosomal proteins as phi X174 DNA for directing the in vitro conversion that rriA is the DNA sequence that determines the mechanism of lagging strand synthesis of ColE1 DNA and that the mechanism of discontinuous synthesis involves the primosomal proteins utilized in the in vitro conversion of phi X174 single strands to the double-stranded replicative form.

Published
1982
Full Text
View/download PDF

39. Replication of bacteriophage M13. XV. Location of the specific nick in M13 replicative form II accumulated in Escherichia coli polAex1

Author

Nomura, N and Ray, D S

Abstract

M13 replicative form II (RFII) DNA was prepared from Escherichia coli RS5052 (polAex1) cells in the late stage of infection, and the DNA sequence at the discontinuity was examined. The data presented here suggest that the single discontinuity in the late stage of infection RFII maps at the same position as the gene II protein nicking site on fd RFI which was determined in vitro (Meyer et al., Nature (London) 278:365-367, 1979) and has a 5' terminal nucleotide sequence identical to that at the nick produced by gene II protein in vitro. The discontinuity in the in vivo RFII appears to be a single break in the phosphodiester backbone, leaving a 3' OH terminus. RFII molecules containing a gap, i.e., missing nucleotides at the site of discontinuity, were not detected.

Published
1980
Full Text
View/download PDF

40. A clear-plaque mutation of bacteriophage M13 affects the regulation of viral DNA synthesis

Author

Farber, M B and Ray, D S

Abstract

A clear-plaque mutation (c2) of bacteriophage M13 has been shown to affect the regulation of viral DNA synthesis. This mutation increases the amount of the duplex replicative form DNA per cell while decreasing the synthesis of viral single strands. The relative synthesis of the M13 gene 5 protein is approximately half that observed in wild-type infections, suggesting that the effect of the c2 mutation on the regulation of viral DNA synthesis is a result of reduced expression of gene 5.

Published
1980
Full Text
View/download PDF

41. Deletion analysis of the cloned replication origin region from bacteriophage M13

Author

Cleary, J M and Ray, D S

Abstract

A cloned 270-nucleotide fragment from the origin region of the M13 duplex replicative form DNA confers an M13-dependent replication mechanism upon the plasmid vector pBR322. This M13 insert permits M13 helper-dependent replication of the hybrid plasmid in polA cells which are unable to replicate the pBR322 replicon alone. Using in vitro techniques, we have constructed several plasmids containing deletions in the M13 DNa insert. The endpoints of these deletions have been determined by DNA sequence analysis and correlated with the transformation and replication properties of each plasmid. Characterization of these deletion plasmids allows the following conclusions. (i) The initiation site for M13 viral strand replication is required for helper-dependent propagation of the chimeric plasmid. (ii) A DNA sequence in the M13 insert, localized between 89 and 129 nucleotides from the viral strand initiation site, is necessary for efficient transformation of polA cells. A chimeric plasmid containing the viral strand initiation site, but lacking this additional 40 nucleotide M13 sequence, transforms helper-infected cells at a frequency approximately 10(4)-fold less than that of plasmids containing this additional DNA segment. (iii) The entire M13 complementary strand origin can be deleted without affecting M13-dependent transformation by the hybrid plasmids. We propose a model in which replication of one strand of duplex chimera initiates by nicking at the gene II protein nicking site in the viral strand of the M13 insert, followed by asymmetric single-strand synthesis. Initiation of the complementary strand possibly occurs within plasmid sequences.

Published
1981
Full Text
View/download PDF

42. Replication of bacteriophage M13. XIV. Differential inhibition of the replication of M13 and M13 miniphage in a mutant of Escherichia coli defective in the 5' leads to 3' exonuclease associated with DNA polymerase I

Author

Chen, T C and Ray, D S

Abstract

Previous studies have shown that M13 single-strand synthesis is inhibited at nonpermissive temperature in Escherichia coli polAexl, a temperature-sensitive mutant defective in the 5' leads to 3' exonuclease activity of polymerase I (T.-C. Chen and D. S. Ray, J. Mol. Biol. 106:589-604, 1976). Under these conditions the formation of covalently closed replicative form (RF) molecules is greatly reduced, and miniature forms of RF accumulate. We show here that the accumulation of mini-RFs is the consequence of a differential inhibition of the replication of unit-length phage and preexisting miniphage rather than a de novo production of miniphage. Mini-RFs do not accumulate even after as many as nine cycles of growth in the mutant host infected only with unit-length phage. Mixed infections of the mutant host with plaque-purified unit-length phage and a single cloned miniphage show that discontinuities in the mini-RFs are joined with higher efficiency than are those contained in unit-length RFs. After a shift to nonpermissive temperature during single-strand synthesis in cells infected with plaque-purified phage alone, M13 RFs are found largely as RFII molecules (RF form having one or more single-strand discontinuities) containing only a single discontinuity in the viral strand. The inability of the accumulated unit-length RFII molecules to actively replicate may reflect the presence of either a bound protein or RNA primer on the 5' terminus of the viral strand and provides further support for the existence of distinct initiation and termination events in the synthesis of the viral strand.

Published
1978
Full Text
View/download PDF

43. Functional half-lives of bacteriophage m13 gene 5 and gene 8 messages

Author

Lica, L and Ray, D S

Abstract

The half-lives of the M13 gene 5 and gene 8 messages were determined by measuring the decay in the rate of synthesis of the gene 5 and gene 8 proteins after inhibition of new RNA chain initiations with rifampin. The gene 5 and gene 8 messages decay with half-lives of approximately 2.5 and 5 min, respectively. We found no evidence of a functional M13 message with a half-life as long as that reported for hybridizable mRNA.

Published
1976
Full Text
View/download PDF

44. Periodic expression of nuclear and mitochondrial DNA replication genes during the trypanosomatid cell cycle.

Author

Pasion, S G, Brown, G W, Brown, L M, and Ray, D S

Abstract

In trypanosomatids, DNA replication in the nucleus and in the single mitochondrion (or kinetoplast) initiates nearly simultaneously, suggesting that the DNA synthesis (S) phases of the nucleus and the mitochondrion are coordinately regulated. To investigate the basis for the temporal link between nuclear and mitochondrial DNA synthesis phases the expression of the genes encoding DNA ligase I, the 51 and 28 kDa subunits of replication protein A, dihydrofolate reductase and the mitochondrial type II topoisomerase were analyzed during the cell cycle progression of synchronous cultures of Crithidia fasciculata. These DNA replication genes were all expressed periodically, with peak mRNA levels occurring just prior to or at the peak of DNA synthesis in the synchronized cultures. A plasmid clone (pdN-1) in which TOP2, the gene encoding the mitochondrial topoisomerase, was disrupted by the insertion of a NEO drug-resistance cassette was found to express both a truncated TOP2 mRNA and a truncated topoisomerase polypeptide. The truncated mRNA was also expressed periodically coordinate with the expression of the endogenous TOP2 mRNA indicating that cis elements necessary for periodic expression are contained within cloned sequences. The expression of both TOP2 and nuclear DNA replication genes at the G1/S boundary suggests that regulated expression of these genes may play a role in coordinating nuclear and mitochondrial S phases in trypanosomatids.

Published
1994

45. Expression of a DNA strand initiation sequence of ColE1 plasmid in a single-stranded DNA phage.

Author

Nomura, N and Ray, D S

Abstract

In order to investigate initiation of H-strand (lagging strand) replication of the plasmid ColE1, the origin region fragment (Hae II-E) of ColE1 was inserted into the intergenic region of filamentous DNA phage M13 and cloned. A site capable of promoting DNA strand initiation on a single-stranded DNA template has been detected on the L-strand (leading strand) of the cloned fragment. The site, named rri-1 rifampicin-resistant initiation), directs conversion of chimeric phage single-stranded DNA to parental replicative form in the presence of rifampicin, which blocks the function of the complementary strand origin of M13. The function of rri-1 is dependent on both the dnaG and dnaB gene products. It is postulated that rri-1 might be an initiation site for synthesis of the lagging DNA strand during unidirectional replication of ColE1 DNA.

Published
1980
Full Text
View/download PDF

46. Cloning and expression of the Escherichia coli replication origin in a single-stranded DNA phage.

Author

Kaguni, J, LaVerne, L S, and Ray, D S

Abstract

The Escherichia coli DNA replication origin (oriC) and the adjacent asparagine synthetase gene (asnA) have been inserted into the duplex replicative form DNA of the single-stranded phage vector M13Goril. By in vitro recombination, the entire oriC asnA-containing plasmid pJS5 was inserted into M13Gori1 in both possible orientations. Both phage types transduce the asnA gene and confer upon the M13 vector the ability to replicate as a plasmid in the E. coli mutant rep3. In rep+ hosts, these phages undergo single-stranded DNA synthesis and viral morphogenesis.

Published
1979
Full Text
View/download PDF

47. Selective cloning of a DNA single-strand initiation determinant from phi X174 replicative-form DNA

Author

Strathearn, M D, Low, R L, and Ray, D S

Abstract

An M13 phage deletion mutant, M13 delta E101, developed as a vector for selecting DNA sequences that direct DNA strand initiation on a single-stranded template, has been used for cloning restriction enzyme digests of phi X174 replicative-form DNA. Initiation determinants, detected on the basis of clear-plaque formation by the chimeric phage, were found only in restriction fragments containing the unique effector site in phi X174 DNA for the Escherichia coli protein n' dATPase (ATPase). Furthermore, these sequences were functional only when cloned in the orientation in which the phi X174 viral strand was joined to the M13 viral strand. A 181-nucleotide viral strand fragment containing this initiation determinant confers a phi X174-type complementary-strand replication mechanism on M13 chimeras. The chimeric phage is converted to the parental replicative form in vivo by a mechanism resistant to rifampin, a specific inhibitor of the normal RNA polymerase-dependent mechanism of M13. In vitro, the chimeric single-stranded DNA promotes the assembly of a functional multiprotein priming complex, or primosome, identical to that utilized by intact phi X174 viral strand DNA. Chimeric phage containing the sequence complementary to the 181-nucleotide viral strand sequence shows no initiation capability, either in vivo or in vitro.

Published
1984
Full Text
View/download PDF

48. Novobiocin Affinity Purification of a Mitochondrial Type II Topoisomerase from the Trypanosomatid Crithidia fasciculata

Author

Melendy, T and Ray, D S

Abstract

A mitochondrial type II DNA topoisomerase (topoIImt) has been purified to near homogeneity from the trypanosomatid Crithidia fasciculata. A rapid purification procedure has been developed based on the affinity of the enzyme for novobiocin, a competitive inhibitor of the ATP-binding moiety of type II topoisomerases. The purified enzyme is capable of ATP-dependent catenation and decatenation of kinetoplast DNA networks as well as catalyzing the relaxation of supercoiled DNA. topoIImt exists as a dimer of a 132-kDa polypeptide. Immunoblots of whole cell lysates show a single predominant band that comigrates with the 132-kDa polypeptide, indicating that the 264-kDa homodimer represents the intact form of the enzyme. Localization of the enzyme within the single mitochondrion of C. fasciculata(Melendy, T., Sheline, C., and Ray, D. S. (1988) Cell, in press) suggests an important role for topoIImt in kinetoplast DNA replication.

Published
1989
Full Text
View/download PDF

49. Sequences within the 5' untranslated region regulate the levels of a kinetoplast DNA topoisomerase mRNA during the cell cycle

Author

Pasion, S G, Hines, J C, Ou, X, Mahmood, R, and Ray, D S

Abstract

Gene expression in trypanosomatids appears to be regulated largely at the posttranscriptional level and involves maturation of mRNA precursors by trans splicing of a 39-nucleotide miniexon sequence to the 5' end of the mRNA and cleavage and polyadenylation at the 3' end of the mRNA. To initiate the identification of sequences involved in the periodic expression of DNA replication genes in trypanosomatids, we have mapped splice acceptor sites in the 5' flanking region of the TOP2 gene, which encodes the kinetoplast DNA topoisomerase, and have carried out deletion analysis of this region on a plasmid-encoded TOP2 gene. Block deletions within the 5' untranslated region (UTR) identified two regions (-608 to -388 and -387 to -186) responsible for periodic accumulation of the mRNA. Deletion of one or the other of these sequences had no effect on periodic expression of the mRNA, while deletion of both regions resulted in constitutive expression of the mRNA throughout the cell cycle. Subcloning of these sequences into the 5' UTR of a construct lacking both regions of the TOP2 5' UTR has shown that an octamer consensus sequence present in the 5' UTR of the TOP2, RPA1, and DHFR-TS mRNAs is required for normal cycling of the TOP2 mRNA. Mutation of the consensus octamer sequence in the TOP2 5' UTR in a plasmid construct containing only a single consensus octamer and that shows normal cycling of the plasmid-encoded TOP2 mRNA resulted in substantial reduction of the cycling of the mRNA level. These results imply a negative regulation of TOP2 mRNA during the cell cycle by a mechanism involving redundant elements containing one or more copies of a conserved octamer sequence within the 5' UTR of TOP2 mRNA.

Published
1996
Full Text
View/download PDF

50. Mutational mechanisms by which an inactive replication origin of bacteriophage M13 is turned on are similar to mechanisms of activation of ras proto-oncogenes

Author

Kim, M H and Ray, D S

Abstract

M13 viral strand synthesis is initiated by nicking of the viral strand of the duplex replicative form by the M13 gene II initiator protein at a specific site within a sequence of about 40 base pairs having dyad symmetry. Efficient replication of the M13 viral strand also requires the presence of an adjacent sequence of ca. 100 base pairs. Together these sequences constitute the minimal origin for M13 viral strand synthesis. A pBR322 derivative having a 182-base-pair insert of M13 DNA contains a functional M13 viral strand origin and, when provided with M13 gene functions in trans, replicates under conditions nonpermissive for the parent plasmid. Chimeric plasmids containing deletions within the sequence flanking the viral strand origin are unable to replicate under these conditions. We isolated spontaneous mutants of M13 based on their ability to activate replication of such plasmids. The mutations found in these strains, as well as several produced by oligonucleotide-directed mutagenesis, all result in the substitution of any of at least four different amino acids for a specific glycine residue near the amino-terminal end of the initiator protein. Other studies have shown that overproduction of the wild-type initiator protein also restores replication. These alternate mechanisms are discussed in terms of their striking similarity to the mechanisms of activation of the ras proto-oncogenes which can be activated either by increased expression of the wild-type protein or by substitution of any of several amino acids for a glycine residue near the amino terminus.

Published
1985
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results