Identification of Chromosomal Genes in Yersinia pestis that Influence Type III Secretion and Delivery of Yops into Target Cells

Pathogenic Yersinia species possess a type III secretion system, which is required for the delivery of effector Yop proteins into target cells during infection. Genes encoding the type III secretion machinery, its substrates, and several regulatory proteins all reside on a 70-Kb virulence plasmid. Genes encoded in the chromosome of yersiniae are thought to play important roles in bacterial perception of host environments and in the coordinated activation of the type III secretion pathway. Here, we investigate the contribution of chromosomal genes to the complex regulatory process controlling type III secretion in Yersinia pestis. Using transposon mutagenesis, we identified five chromosomal genes required for expression or secretion of Yops in laboratory media. Four out of the five chromosomal mutants were defective to various extents at injecting Yops into tissue culture cells. Interestingly, we found one mutant that was not able to secrete in vitro but was fully competent for injecting Yops into host cells, suggesting independent mechanisms for activation of the secretion apparatus. When tested in a mouse model of plague disease, three mutants were avirulent, whereas two strains were severely attenuated. Together these results demonstrate the importance of Y. pestis chromosomal genes in the proper function of type III secretion and in the pathogenesis of plague

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

The arts in the lives of Australian veterinarians: a preliminary study

Objective: To assess the role of the arts in the lives of those veterinary students and veterinarians who could be found to be active in one or more of the arts. Procedure: Veterinary students and veterinarians active in the arts were sought by advertisement and personal contact. Respondents each completed a questionnaire, which was analysed using SAS. Results: Of the 55 respondents (43 veterinarians; 12 students), 73% were involved in music, 31% in theatre, 27% in writing and 15% art, but for more than 80% this occupied no more than 10 hours/week, about one quarter of the time for veterinary work. Although most would like to spend more time on the artistic activity, this was generally limited by the need to earn an income from veterinary work. Music and drama provided satisfaction, variety, and relaxation while catering to creative needs. A creative outlet and satisfaction was very important for writers as well, but they also valued the intellectual stimulation. A complex relationship existed between the artistic and the veterinary activities, but the nature of this relationship varied both between type of artistic activity, and the person concerned. Conclusions: Veterinary science and the arts can complement one another with each making important contributions to the person and the artistic field involved, even though limitations of time for the arts may cause frustration

Natural Law

In early modern moral and political philosophy, the term “natural law” referred to a universal moral norm which human beings are able to recognize by using their natural faculties, without the supernatural information offered by the Bible, and which is, in one way or another, connected to human nature. Natural law had been a standard topic already in medieval philosophy, but the idea of such a universal norm received new significance as Europeans confronted and colonized non-Christian people, the Christian church itself was divided into rival confessional groups, and independent territorial states became the dominant form of political organization in Europe. As a result of these developments, the character, content and implications of natural law were widely debated in early modern scholarly literature. Even though all this was done by using concepts adopted from medieval scholasticism, early modern natural law should not be seen as a unified and evolving philosophical tradition, but rather as a series of attempts to redefine a collectively shared moral and legal vocabulary in order to justify what were often quite dissimilar political aims (see, e.g., Haakonssen and Seidler 2016; Westerman 1998; Hochstrasser 2000; Hunter 2011; Stolleis 2008).Peer reviewe

Sociability

How are individuals able to establish peaceful and enduring societies? Although the problem of sociability has been a recurrent concern for moral and political philosophers since antiquity, the early modern period marks an important shift in the conceptualization of human sociability. Moral skepticism, numerous ferocious wars, and the rise of sovereign states prompted the novel needed to study the normative and psychological underpinnings of social order. From the sixteenth century onward, sociability began to function as a bridge concept that was applied to theories of morality and moral psychology, political philosophy, history, international relations, and political economy (see, e.g., Piirimäe and Schmidt 2015; Sagar 2018; Ahnert and Manning 2011; Fiorillo and Grunert 2009; Vollhardt 2001). This entry introduces the early modern conceptions of sociability by focusing on the debate concerning the question how are men turned into social and political animals. Is sociability natural for human beings, or is it merely an artificial device that restrains and motivates the actions of naturally unsociable individuals? During the course of the early modern period, the notion of sociability as an innate inclination that could provide sufficient foundations for mutual sociability in large societies was questioned. As a result, the view of man as a naturally social and political being was gradually replaced by the idea of sociability as an artificial product of historically situated societies.Peer reviewe