Restriction-modification gene complexes as selfish gene entities: Roles of a regulatory system in their establishment, maintenance, and apoptotic mutual exclusion

We have reported some type II restriction-modification (RM) gene complexes on plasmids resist displacement by an incompatible plasmid through postsegregational host killing. Such selfish behavior may have contributed to the spread and maintenance of RM systems. Here we analyze the role of regulatory genes (C), often found linked to RM gene complexes, in their interaction with the host and the other RM gene complexes. We identified the C gene of EcoRV as a positive regulator of restriction. A C mutation eliminated postsegregational killing by EcoRV. The C system has been proposed to allow establishment of RM systems in new hosts by delaying the appearance of restriction activity. Consistent with this proposal, bacteria preexpressing ecoRVC were transformed at a reduced efficiency by plasmids carrying the EcoRV RM gene complex. Cells carrying the BamHI RM gene complex were transformed at a reduced efficiency by a plasmid carrying a PvuII RM gene complex, which shares the same C specificity. The reduction most likely was caused by chromosome cleavage at unmodified PvuII sites by prematurely expressed PvuII restriction enzyme. Therefore, association of the C genes of the same specificity with RM gene complexes of different sequence specificities can confer on a resident RM gene complex the capacity to abort establishment of a second, incoming RM gene complex. This phenomenon, termed “apoptotic mutual exclusion,” is reminiscent of suicidal defense against virus infection programmed by other selfish elements. pvuIIC and bamHIC genes define one incompatibility group of exclusion whereas ecoRVC gene defines another.

Conservation of fibroblast growth factor function in lens regeneration

In urodele amphibians, lens induction during development and regeneration occurs through different pathways. During development, the lens is induced from the mutual interaction of the ectoderm and the optic vesicle, whereas after lentectomy the lens is regenerated through the transdifferentiation of the iris-pigmented epithelial cells. Given the known role of fibroblast growth factors (FGFs) during lens development, we examined whether or not the expression and the effects of exogenous FGF during urodele lens regeneration were conserved. In this paper, we describe expression of FGF-1 and its receptors, FGFR-2 (KGFR and bek variants) and FGFR-3, in newts during lens regeneration. Expression of these genes was readily observed in the dedifferentiating pigmented epithelial cells, and the levels of expression were high in the lens epithelium and the differentiating fibers and lower in the retina. These patterns of expression implied involvement of FGFs in lens regeneration. To further elucidate this function, we examined the effects of exogenous FGF-1 and FGF-4 during lens regeneration. FGF-1 or FGF-4 treatment in lentectomized eyes resulted in the induction of abnormalities reminiscent to the ones induced during lens development in transgenic mice. Effects included transformation of epithelial cells to fiber cells, double lens regeneration, and lenses with abnormal polarity. These results establish that FGF molecules are key factors in fiber differentiation, polarity, and morphogenesis of the lens during regeneration even though the regenerating lens is induced by a different mechanism than in lens development. In this sense, FGF function in lens regeneration and development should be regarded as conserved. Such conservation should help elucidate the mechanisms of lens regeneration in urodeles and its absence in higher vertebrates.

Solution structure of DFF40 and DFF45 N-terminal domain complex and mutual chaperone activity of DFF40 and DFF45

Apoptotic DNA fragmentation is mediated by a caspase-activated DNA fragmentation factor (DFF)40. Expression and folding of DFF40 require the presence of DFF45, which also acts as a nuclease inhibitor before DFF40 activation by execution caspases. The N-terminal domains (NTDs) of both proteins are homologous, and their interaction plays a key role in the proper functioning of this two-component system. Here we report that the NTD of DFF45 alone is unstructured in solution, and its folding is induced upon binding to DFF40 NTD. Therefore, folding of both proteins regulates the formation of the DFF40/DFF45 complex. The solution structure of the heterodimeric complex between NTDs of DFF40 and DFF45 reported here shows that the mutual chaperoning includes the formation of an extensive network of intermolecular interactions that bury a hydrophobic cluster inside the interface, surrounded by intermolecular salt bridges.

Historical overview: Searching for replication help in all of the rec places

For several decades, research into the mechanisms of genetic recombination proceeded without a complete understanding of its cellular function or its place in DNA metabolism. Many lines of research recently have coalesced to reveal a thorough integration of most aspects of DNA metabolism, including recombination. In bacteria, the primary function of homologous genetic recombination is the repair of stalled or collapsed replication forks. Recombinational DNA repair of replication forks is a surprisingly common process, even under normal growth conditions. The new results feature multiple pathways for repair and the involvement of many enzymatic systems. The long-recognized integration of replication and recombination in the DNA metabolism of bacteriophage T4 has moved into the spotlight with its clear mechanistic precedents. In eukaryotes, a similar integration of replication and recombination is seen in meiotic recombination as well as in the repair of replication forks and double-strand breaks generated by environmental abuse. Basic mechanisms for replication fork repair can now inform continued research into other aspects of recombination. This overview attempts to trace the history of the search for recombination function in bacteria and their bacteriophages, as well as some of the parallel paths taken in eukaryotic recombination research.

How Language and Stereotypes Affect the Help-Seeking Behaviors of Victims of Female-on-Female Sexual Assault

While much attention has been paid to the experiences of the female victims of male-perpetrated sexual assault, relatively little attention has been paid to the experiences of female-on-female sexual assault. However, female-on-female sexual assault can and does occur within lesbian and queer communities. What literature there is on the topic demonstrates that gender stereotypes, as well as stereotypes about the lesbian and queer communities, play a role in the decision process to seek help. This paper seeks to analyze the role of language and stereotypes in the help-seeking behaviors of victims of female-on-female sexual assault, using Relational Frame Theory as a framework.

Once Upon a Time in Therapy: Crafting Therapeutic Narratives to Help Familiarize Children with the Therapeutic Process.

Young children often harbor misconceptions about psychotherapy and the role of psychologists. These misconceptions are ignited by rumors and misinformation that are provided to the child by a variety of sources and can compromise both the effectiveness of therapy and the therapeutic dyad. In this paper we explore how recent trends in patient engagement in child psychotherapy, cultural dynamics between patients and practitioners, and children's lack of knowledge surrounding mental health services can negatively impact therapy. Wednesday Afternoons with Dr. J. (WADJ) is a whimsical fictional therapeutic narrative created to inform children about aspects of the therapeutic process while providing adults with tangible structure surrounding how to talk to children about mental healthcare. The advantages of utilizing this narrative to prime children for therapy are discussed, as are methods for promoting the narrative to the greater community.

Asking For Help: Vulnerability within Consultative Assessment A Couples Therapy Example.

In many different ways psychologists are challenged to evaluate their work and be accountable when therapy is not progressing. One time honored approach to addressing the lack of progress is to seek formal psychological assessment to gain a better diagnostic understanding as well as treatment recommendations. The perspective on the purpose of the assessment seems to have changed however. Historically, the presumption was that there was some kind of pathology that the clinician was not seeing, where currently the perspective seems to be shifting more towards a focus on what might not be working in the therapeutic process. This shift in focus has led to new styles of collaborative and consultative assessment such as Therapeutic Assessment. Therapeutic Assessment was developed by Stephen Finn and has shown a great deal of promise helping clients and therapists gain valuable insight and move toward meaningful life changes (1998). Amidst the promise of consultative assessment also lie potential challenges for the referring clinician. This paper will explore the nature of consultative relationships in the field of mental health and the current thoughts about the advantages and challenges of these relationships. Using a case study format, it will discuss and illustrate issues of professional vulnerability that can arise during these relationships and postulate that a similar vulnerability could be present during a consultative assessment. Recommendations are made for maximizing the success of this type of assessment, and ideas for future research are reviewed. Through the lens of a couples Therapeutic Assessment case, this paper will examine what it is about this unique kind of professional relationship that garners such powerful potential and pitfalls.

How online applications can help to achieve integral learning

The development of transversal competencies provides an integral education. However, its practical implementation among different subjects is not a trivial task. There are several issues that should be previously solved in an optimal way to take advantage of the synergy among subjects. Main issues are: i) the need for a common space for the documents management, ii) the availability of the document everywhere and anytime, and iii) the possibility to collaborate in the documents edition tasks. It was implemented a virtual portfolio for the students which allows the assessment of all the subjects in a global way. To this goal we used the Google apps due to its free access, availability and suitability for the collaborative editing tasks.

Short nomenclator or vocabular in English and Hebrew: composed alphabetically for the use and benefit of my pupils in particular and for the advantage of those who are desirous to obtain the knowledge of the Hebrew tongue in general, which may be that great help to understand not only ye sacred oracles in their original, but even any Jewish author (so far as concern owns) as also it may give great insight in ye tongue to those, as to compose it, a work altogether new, [ca. 1735]

Headed on the first page with the words "Nomenclatura hebraica," this handwritten volume is a vocabulary with the Hebrew word in the left column, and the English translation on the right. While the book is arranged in sections by letter, individual entries do not appear in strict alphabetical order. The small vocabulary varies greatly and includes entries like enigma, excommunication, and martyr, as well as cucumber and maggot. There are translations of the astrological signs at the end of the volume. Poem written at the bottom of the last page in different hand: "Women when good the best of saints/ that bright seraphick lovely/ she, who nothing of an angel/ wants but truth & immortality./ Verse 2: Who silken limbs & charming/ face. Keeps nature warm."