Roles of heavy and light chains in IgM polymerization.

IgM antibodies are secreted as multisubunit polymers that consist of as many as three discrete polypeptides: mu heavy chains, light (L) chains, and joining (J) chains. We wished to determine whether L chains that are required to confer secretory competence on immunoglobulin molecules must be present for IgM to polymerize--that is, for intersubunit disulfide bonds to form between mu chains. Using a L-chain-loss variant of an IgM-secreting hybridoma, we demonstrated that mu chains were efficiently polymerized independent of L chains, in a manner similar to that observed for conventional microL complexes, and that the mu polymers incorporated J chain. These mu polymers were not secreted but remained associated with the endoplasmic reticulum-resident chaperone BiP (GRP78). This finding is consistent with the endoplasmic reticulum being the subcellular site of IgM polymerization. We conclude that mu chain alone has the potential to direct the polymerization of secreted IgM, a process necessary but not sufficient for IgM to attain secretory competence.

Roles of nitric oxide in tumor growth.

A subclone of the human colon adenocarcinoma cell line DLD-1, which grew reproducibly as subcutaneous tumors in nude mice, was isolated. Such cells, when engineered to generate nitric oxide (NO) continuously, grew more slowly in vitro than the wild-type parental cells. This growth retardation was reversed by the addition of N-iminoethyl-L-ornithine. In nude mice, however, the tumors from these cells grew faster than those derived from wild-type cells and were markedly more vascularized, suggesting that NO may act as part of a signaling cascade for neovascularization. Recent observations that the generation of NO in human breast and gynecological cancers correlates positively with tumor grade are consistent with this hypothesis. We suggest that NO may have a dual pro- and antitumor action, depending on the local concentration of the molecule.

Sights for Sounds: The Roles of Illuminated Initials in Italian Music Manuscripts

The scholarship on illuminated initials is substantial, yet there is a significant absence of information when discussing the initials found in music manuscripts specifically. In this paper, I endeavor to supplement the current scholarship by focusing my research on music manuscripts produced in Italy between 1250 and 1500 A.D. in order to provide examples of the relationships between image, music, and text in the context of use. I use mainly iconographic research methods, though a considerable amount of background information is reliant on the research of other authors in the field of medieval philosophy and theology. Through my research I have concluded that the use of illuminated initials in medieval Italian music manuscripts enhances the function of the manuscript by providing another layer of understanding which audience members could use to aid them in their meditation, prayer, and in the performance of the music.

The Plasmodium serine-type SERA proteases display distinct expression patterns and non-essential in vivo roles during life cycle progression of the malaria parasite

Parasite proteases play key roles in several fundamental steps of the Plasmodium life cycle, including haemoglobin degradation, host cell invasion and parasite egress. Plasmodium exit from infected host cells appears to be mediated by a class of papain-like cysteine proteases called 'serine repeat antigens' (SERAs). A SERA subfamily, represented by Plasmodium falciparum SERA5, contains an atypical active site serine residue instead of a catalytic cysteine. Members of this SERAser subfamily are abundantly expressed in asexual blood stages, rendering them attractive drug and vaccine targets. In this study, we show by antibody localization and in vivo fluorescent tagging with the red fluorescent protein mCherry that the two P. berghei serine-type family members, PbSERA1 and PbSERA2, display differential expression towards the final stages of merozoite formation. Via targeted gene replacement, we generated single and double gene knockouts of the P. berghei SERAser genes. These loss-of-function lines progressed normally through the parasite life cycle, suggesting a specialized, non-vital role for serine-type SERAs in vivo. Parasites lacking PbSERAser showed increased expression of the cysteine-type PbSERA3. Compensatory mechanisms between distinct SERA subfamilies may thus explain the absence of phenotypical defect in SERAser disruptants, and challenge the suitability to develop potent antimalarial drugs based on specific inhibitors of Plasmodium serine-type SERAs.

Affective Commitment and Job Satisfaction among Non-family Employees: Investigating the Roles of Justice Perceptions and Psychological Ownership

Due to numerous characteristics often attributed to family firms, they constitute a unique context for non-family employees’ justice perceptions. These are linked to non-family employees’ pro-organizational attitudes and behaviors, which are essential for family firms’ success. Even though scholarly interest in non-family employees’ justice perceptions has increased, more research is still needed, also because the mechanism connecting justice perceptions and favorable outcomes is not fully understood yet. We address this gap by explicitly investigating non-family employees’ justice perceptions and by introducing psychological ownership as a mediator in the relationships between justice perceptions (distributive and procedural) and common work attitudes (affective commitment and job satisfaction). Our analysis of a sample of 310 non-family employees from Germany and German-speaking Switzerland reveals that psychological ownership mediates the relationships between distributive justice and affective commitment as well as job satisfaction. This represents valuable contributions to family business research, organizational justice and psychological ownership literature, and to practice.

Advances in Research on Semantic Roles

Especially in functional-typological linguistics, semantic roles have been studied thoroughly, because they constitute a good starting point for any study on argument marking due to their semantically defined nature. However, the very concept of semantic roles is far from being without problems, and there is still no consensus on how the roles are best defined. In this volume, the notion will be discussed from novel perspectives with the aim of providing new insights into our understanding of semantic roles. Two of the papers deal with semantic role clusters, one with semantic roles in verbless constructions, one with diachrony of semantic roles and two with individual semantic roles that have not been studied in too much detail in previous studies. The book may not offer answers to all questions the readers may have, but at least it raises interesting further questions relevant to arriving at a better understanding of semantic roles.

Measuring up : questions and answers about state roles in educational accountability.

Cover title.

A second census of Finnegans wake; an index of the characters and their roles. Rev. and expanded from the first Census.

Mode of access: Internet.

Bond financing and transportation infrastructure: exploring concepts and roles.

Mode of access: Internet.

Social security and the changing roles of men and women /

Summary (31 p.) inserted at end

Federal librarians in the 21st century : changing roles in the electronic age : summary report on conference proceedings : Wednesday, September 15, 1993, Mumford Room, James Madison Memorial Building, Library of Congress.

Shipping list no.: 94-0074-P.