The proper assembly and operation of the mitotic spindle is essential to ensure the accurate segregation of chromosomes and to position the cytokinetic furrow during cell division in eukaryotes. Not only are dynamic microtubules required but also the concerted actions of multiple motor proteins are necessary to effect spindle pole separation, chromosome alignment, chromatid segregation, and spindle elongation. Although a number of motor proteins are known to play a role in mitosis, there remains a limited understanding of their full range of functions and the details by which they interact with other spindle components. The kinesin-5 (BimC/Eg5) family of motors is largely considered essential to drive spindle pole separation during the initial and latter stages of mitosis. We have deleted the gene encoding the kinesin-5 member in Dictyostelium, (kif13), and find that, in sharp contrast with results found in vertebrate, fly, and yeast organisms, kif13(-) cells continue to grow at rates indistinguishable from wild type. Phenotype analysis reveals a slight increase in spindle elongation rates in the absence of Kif13. More importantly, there is a dramatic, premature separation of spindle halves in kif13(-) cells, suggesting a novel role of this motor in maintaining spindle integrity at the terminal stages of division.
‘Post-truth’ was not a new concept when it was selected as the international word of the year (2016) by Oxford Dictionaries. In the context of communications research, scholars were discussing journalism in the ‘post-factual’ age some thirty years ago (Ettema 1987). In the digital era, journalistic practice itself has changed; stories are generated by a multiplicity of actors in a participative and interactive way. This paper contemplates the nature of journalists’ information practices in the 21st century and relates these to the roles of information and social media in civil society. The methodology draws on the findings of pilot research studies investigating journalists’ information practices in the digital realm (Martin 2014; 2015) and investigates the pressures of verification. The author posits that that we are ostensibly living in a ‘post-truth’ society largely due to the impact of changes in the news milieu in the digital age. With so many diverse voices in the mix, it is increasingly difficult for citizens to separate fact from fiction; journalists thus have a role as verifiers. It is crucial for information consumers (citizenry) to have the requisite skills and knowledge to critically evaluate media content and deal with information and communication overload.
Social media now plays a pivotal role in how broadcast media engages with their audiences. This paper contemplates the nature of our digital media culture, the diversity of actors involved and how the role of the journalist has evolved. The methodology includes examining the findings of a pilot research study investigating journalists' information practices in the digital realm. Two theoretical frameworks from the discipline of Information Science are introduced to reorient research practices. The findings reveal digital journalism facilitates richer and more expansive storytelling, with connectivity between experts, journalists and the public. The author posits that the citizeninformant is reconceptualised in the news milieu.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.