Bioinformatic and in vitro characterization of primase-polymerase enzymes from viruses that infect actinobacterial hosts

Primase-polymerases (prim-pols) are enzymes that exhibit primase, polymerase, and potential helicase-like activities by way of a bifunctional N-terminal prim-pol domain and a C-terminal ATPase domain. Presented is a multifaceted analysis of prim-pols encoded by actinophages, or viruses that infect Actinobacterial hosts. The aims of this study are to bioinformatically characterize all identifiable actinophage-encoded prim-pols and to biochemically characterize the prim-pol encoded by mycobacteriophage Larva, including determining protein-protein interactions between Larva’s prim-pol and host Mycobacterium smegmatis proteins using a bacterial two-hybrid system. Bioinformatic analyses reveal nearly 600 actinophages encoding prim-pols that span a variety of host types, genome sizes, conserved domains, and encoded genetic metabolism proteins. A novel class of truncated prim-pols that contain an intact prim-pol domain but lack any additional C-terminal domain has been identified. Most phages encoding truncated prim-pols also encode a separate protein resembling the ATPase domain of full-length prim-pols. Interestingly, the C-terminal functional domains of full-length prim-pols vary from phage to phage aside from a conserved nucleotide binding motif. The C-terminal domains of prim-pols allow them to be grouped more narrowly than by their N-terminal prim-pol domain alone. To begin to understand the importance of prim-pols in actinophage DNA replication, a detailed characterization has been performed of a prim-pol from mycobacteriophage Larva, which is the virus’ only encoded DNA polymerase. Larva’s prim-pol exhibits Mg2+-dependent primase/polymerase activity on an unprimed ssDNA substrate in the presence of dNTPs. It also binds multiple DNA substrates and translocates on ssDNA in the presence of ATP. CRISPR interference silencing of prim-pol is lethal to Larva, indicating it is essential for viral survival. Bacterial two-hybrid analysis reveals interactions between Larva’s prim-pol and at least five M. smegmatis proteins, including transcription and nucleic acid synthesis proteins. Based on these results, it is hypothesized that despite sharing a conserved prim-pol domain, actinophage-encoded prim-pols fulfill a variety of functions in the replication of phage DNA, some critical to viral survival, depending on the domain organization of the proteins’ C-termini and on the phages’ individual genomic architectures

On Hopf algebra structures over free operads

The operad Lie can be constructed as the operad of primitives Prim As from the operad As of associative algebras. This is reflected by the theorems of Friedrichs, Poincare'-Birkhoff-Witt and Cartier-Milnor-Moore. We replace As by families of free operads P, which include the operad Mag freely generated by a noncommutative non-associative binary operation and the operad of Stasheff polytopes. We obtain Poincare'-Birkhoff-Witt type theorems and collect information about the operads Prim P, e.g. in terms of characteristic functions.Comment: 25pages, uses elsart.cls, paper extracted from habilitation thesis (math.RA/0407074), revised (more details in sections 2,3,4, and 6

RELATIONSHIP MARKETING OF SERVICES: AN ANALYSIS OF SERVICE QUALITY AND SERVICE ENCOUNTERS THROUGH RELATIONAL NORMS -A DYADIC APPROACH BETWEEN BANK ACCOUNT MANAGERS AND SMES -

The combined pressures of desintermediation, deregulation, and industrial restructuring have helped to redefine the nature and importance of bank-client relationships (Schell, 1996). Directors or treasurers of companies often recognize that their relationship is with the bank account manager, rather than with the bank (Wood & al., 1995). This is the reason why the role played by the service provider as the individual who manages the relationship between the firm and the buyer is of special importance (Czepiel, 1990). The essentially social nature of service encounters, a short-term phenomenon, provides the occasions in which buyer and seller negotiate the terms of their exchange relationship, a long-term phenomenon. Defined as the mutual recognition of special status between exchange partners, exchange relationships ensure efficiency for the buyer, as they mitigate market volatility for the seller. Understanding how economic exchange is played out against a background of social exchange can yield important insights, which can then be implemented by undertaking specific actions. One implication is that research must include both customer and provider perceptions and perspectives as the focal unit (Czepiel, 1990). Moreover, each purchase decision takes into account not only the immediate cost/benefit analysis but also the relationship past history and the possible future as well (Dwyer et al. 1987; Macneil, 1980). This paper aims, through exploratory research, (conducted on 13 dyads, 13 SMEs and their account managers) to analyze long-term relationships through a new framework to get a better understanding of how customers evaluate service quality, service encounters, and on how they decide whether or not to repatronize. It also aims to extend and develop the understanding of service quality perceptions and development. More specifically, this exploratory research has focused on four different objectives: • the author wanted to get a better in-depth knowledge of the banks' SME market; • there was a need to identify the main components of the creation and development of the relationship between a bank and its clients; • there was a need to confirm the reality of the relational norms as defined by Macneil; • finally, the author needed to get some verbatim for an upcoming questionnaire as well as identifying some potential difficulties for future research implementation. After a brief review of the theoretical background, this article presents the methodology used for this study. Then, there will be a presentation of the results of the two content analyses we have conducted. Finally the conclusion will present the limits of this work and research avenues will be drawn.relationship marketing; service quality; service encounters; relational norms; Macneil

Secondary to primary ratio and the continuous acceleration

A general formula for the sec/prim ratio, independently of any details of the propagation and acceleration model is presented. In the limit of equal fragmentation paths for primaries and secondaries, this ratio at a given momentum nucleon is proportional only to the mean path of the observed primaries at that moment. It is shown that it is unlikely to get a decreasing sec/prim ratio with energy if an acceleration process takes place during particle propagation in the interstellar medium (ISM)

LONG-TERM RELATIONSHIP TERMINATION MODEL: A STUDY OF THE ANTECEDENTS OF THE SERVICE ENCOUNTER EVALUATION AND OF THE MAINTENANCE/TERMINATION DECISION

This paper describes the objectives, the marketing issues, the methodology and the anticipated contribution of our doctoral research. The main focus is on identifying and understanding the antecedents of long term relationship dissolutionbusiness relationship termination; dissolution; service encounter evaluation