First Report of \u3ci\u3eYersinia ruckeri\u3c/i\u3e Biotype 2 in the USA

A polyphasic characterization of atypical isolates of Yersinia ruckeri (causative agent of enteric redmouth disease in trout) obtained from hatchery-reared brown trout Salmo trutta in South Carolina was performed. The Y. ruckeri isolates were biochemically and genetically distinct from reference cultures, including the type strain, but were unequivocally ascribed to the species Y. ruckeri, based on API 20E, VITEK, fatty acid methyl ester profiles, and 16S rRNA gene sequencing analysis. These isolates were nonmotile and unable to hydrolyze Tween 20/80 and were therefore classified as Y. ruckeri biotype 2. Genetic fingerprint typing of the isolates via enterobacterial repetitive intergenic consensus (amplified by polymerase chain reaction) and fragment length polymorphism showed biotype 2 as a homogeneous group distinguishable from other Y. ruckeri isolates. This is the first report of Y. ruckeri biotype 2 in the USA

A New Species of \u3ci\u3eSprirorchis\u3c/i\u3e MacCallum, 1918, (Digenea: Schistosomatoidea) and \u3ci\u3eSpirorchis scripta\u3c/i\u3e Stunkard, 1923, Infecting River Cooter, \u3ci\u3ePseudemys concinna\u3c/i\u3e (Le Conte, 1830), (Testudines: Emydidae) in the Pascagoula River, Mississippi, U.S.A., Including an Updated Phylogeny for \u3ci\u3eSpirorchis\u3c/i\u3e spp.

River cooters (Pseudemys concinna [Le Conte, 1830]) from the Pascagoula River (30°37′07.67″N; 88°36′44.53″W; Mississippi, U.S.A.) were infected by Spirorchis scripta Stunkard, 1923, and Spirorchis testiplexus n. sp. The new species resembles Spirorchis artericola (Ward, 1921) Stunkard, 1921, and Spirorchis innominatus Ward, 1921 (type species), by having a median esophageal diverticulum, ceca that extend slightly posterior to the genitalia, 10 testes, and a testicular column that extends anteriad to near the cecal bifurcation. Based on a comparative morphological study of existing type materials, vouchers, and published descriptions of similar congeners, S. testiplexus is unique by the combination of having a proportionally wider body, laterally directed cecal diverticula, deeply lobed testes, a testicular column that fills the intercecal space, and an external seminal vesicle that occupies the space between the posterior-most testis and the ovary and that passes dorsal or dorsolateral to the ovary. The large-subunit rDNA (28S) Bayesian inference phylogenetic analysis (including 16 turtle blood fluke species of 7 genera) showed a strongly supported monophyletic Spirorchis MacCallum, 1918, grouping sister to Spirhapalum siamensis Tkach, Snyder, and Vaughn, 2009

Drosophila Models of Cell Polarity and Cell Competition in Tumourigenesis

Cell competition is an important surveillance mechanism that measures relative fitness between cells in a tissue during development, homeostasis, and disease. Specifically, cells that are >less fit> (losers) are actively eliminated by relatively >more fit> (winners) neighbours, despite the less fit cells otherwise being able to survive in a genetically uniform tissue. Originally described in the epithelial tissues of Drosophila larval imaginal discs, cell competition has since been shown to occur in other epithelial and non-epithelial Drosophila tissues, as well as in mammalian model systems. Many genes and signalling pathways have been identified as playing conserved roles in the mechanisms of cell competition. Among them are genes required for the establishment and maintenance of apico-basal cell polarity: the Crumbs/Stardust/Patj (Crb/Sdt/Patj), Bazooka/Par-6/atypical Protein Kinase C (Baz/Par-6/aPKC), and Scribbled/Discs large 1/Lethal (2) giant larvae (Scrib/Dlg1/L(2)gl) modules. In this chapter, we describe the concepts and mechanisms of cell competition, with emphasis on the relationship between cell polarity proteins and cell competition, particularly the Scrib/Dlg1/L(2)gl module, since this is the best described module in this emerging field.JELM is supported by Australian Research Council (Grant DP170102549), NFL is supported by a La Trobe University PhD student scholarship, and HER is supported by funds from the School for Molecular Science at La Trobe University

The legacy of Drosophila imaginal discs

The study of Drosophila imaginal discs has contributed to a number of discoveries in developmental and cellular biology. In addition to the elucidation of the role of tissue compartments and organ-specific master regulator genes during development, imaginal discs have also become well established as models for studying cellular interactions and complex genetic pathways. Here, we review key discoveries resulting from investigations of these epithelial precursor organs, ranging from cell fate determination and transdetermination to tissue patterning. Furthermore, the design of increasingly sophisticated genetic tools over the last decades has added value to the use of imaginal discs as model systems. As a result of tissue-specific genetic screens, several components of developmentally regulated signaling pathways were identified and epistasis revealed the levels at which they function. Discs have been widely used to assess cellular interactions in their natural tissue context, contributing to a better understanding of growth regulation, tissue regeneration, and cancer. With the continuous implementation of novel tools, imaginal discs retain significant potential as model systems to address emerging questions in biology and medicine