Increased diversification rates follow shifts to bisexuality in liverworts

Shifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts. We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests. We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present. Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism

Actin's propensity for dynamic filament patterning

Actin, through its various forms of assembly, provides the basic framework for cell motility, cell shape and intracellular organization in all eukaryotic cells. Many other cellular processes, for example endocytosis and cytokinesis, are also associated with dynamic changes of the actin cytoskeleton. Important prerequisites for actin's functional diversity are its intrinsic ability to rapidly assemble and disassemble filaments and its spatially and temporally well-controlled supramolecular organization. A large number of proteins that interact with actin, collectively referred to as actin-binding proteins (ABPs), carefully orchestrate different scenarios. Since its isolation in 1994 [Machesky, L.M. et al. (1994) J. Cell Biol. 127, 107-115], the Arp2/3 complex containing the actin-related proteins Arp2 and Arp3 has evolved to be one of the main players in the assembly and maintenance of many actin-based structures in the cell (for review see [Borths, E.L. and Welch, M.D. (2002) Structure 10, 131-135; May, R.C. (2001) Cell Mol. Life Sci. 58, 1607-1626; Pollard, T.D. et al. (2000) Rev. Biophys. Biomol. Struct. 29, 545-576; Welch, M.D. (1999) Trends Cell Biol. 11, 423-427]). In particular, when it comes to the assembly of the intricate branched actin network at the leading edge of lamellipodia, the Arp2/3 complex seems to have received all the attention in recent years. In parallel, but not so much in the spotlight, several reports showed that actin on its own can assume different conformations [Bubb, M.R. et al. (2002) J. Biol. Chem. 277, 20999-21006; Schoenenberger, C.-A. et al. (1999) Microsc. Res. Tech. 47, 38-50; Steinmetz, M.O. et al. (1998) J. Mol. Biol. 278, 793-811; Steinmetz, M.O. et al. (1997) J. Cell Biol. 138, 559-574; Millonig, R., Salvo, H. and Aebi, U. (1988) J. Cell Biol. 106, 785-796] through which it drives its supramolecular patterning, and which ultimately generate its functional diversity

Lay involvement in the analysis of qualitative data in health services research:A descriptive study

Plain English summary: There is a consensus that patients and the public should be involved in research in a meaningful way. However, to date, lay people have been mostly involved in developing research ideas and commenting on patient information.We previously published a paper describing our experience with lay partners conducting observations in a study of how patients in hospital are involved with their medicines. In a later part of the same study, lay partners were also involved in analysing interviews that a researcher had conducted with patients, carers and healthcare professionals about patient and carer involvement with medicines in hospital. We therefore wanted to build on our previous paper and report on our experiences with lay partners helping to conduct data analysis. We therefore interviewed the lay members and researchers involved in the analysis to find out their views.Both lay members and researchers reported that lay partners added value to the study by bringing their own perspectives and identifying further areas for the researcher to look for in the interviews. In this way researchers and lay partners were able to work together to produce a richer analysis than would have been possible from either alone. Abstract: Background It is recognised that involving lay people in research in a meaningful rather than tokenistic way is both important and challenging. In this paper, we contribute to this debate by describing our experiences of lay involvement in data analysis.MethodsWe conducted semi-structured interviews with the lay partners and researchers involved in qualitative data analysis in a wider study of inpatient involvement in medication safety. The interviews were transcribed verbatim and coded using open thematic analysis.ResultsWe interviewed three lay partners and the three researchers involved. These interviews demonstrated that the lay members added value to the analysis by bringing their own perspectives; these were systematically integrated into the analysis by the lead researcher to create a synergistic output. Some challenges arose, including difficulties in recruiting a diverse range of members of the public to carry out the role; however there were generally fewer challenges in data analysis than there had been with our previous experience of lay partners' involvement in data collection.ConclusionsLay members can add value to health services research by being involved in qualitative data analysis