The Stromal Processing Peptidase of Chloroplasts is Essential in Arabidopsis, with Knockout Mutations Causing Embryo Arrest after the 16-Cell Stage

Stromal processing peptidase (SPP) is a metalloendopeptidase located in the stroma of chloroplasts, and it is responsible for the cleavage of transit peptides from preproteins upon their import into the organelle. Two independent mutant Arabidopsis lines with T-DNA insertions in the SPP gene were analysed (spp-1 and spp-2). For both lines, no homozygous mutant plants could be detected, and the segregating progeny of spp heterozygotes contained heterozygous and wild-type plants in a ratio of 2∶1. The siliques of heterozygous spp-1 and spp-2 plants contained many aborted seeds, at a frequency of ∼25%, suggesting embryo lethality. By contrast, transmission of the spp mutations through the male and female gametes was found to be normal, and so gametophytic effects could be ruled out. To further elucidate the timing of the developmental arrest, mutant and wild-type seeds were cleared and analysed by Nomarski microscopy. A significant proportion (∼25%) of the seeds in mutant siliques exhibited delayed embryogenesis compared to those in wild type. Moreover, the mutant embryos never progressed normally beyond the 16-cell stage, with cell divisions not completing properly thereafter. Heterozygous spp mutant plants were phenotypically indistinguishable from the wild type, indicating that the spp knockout mutations are completely recessive and suggesting that one copy of the SPP gene is able to produce sufficient SPP protein for normal development under standard growth conditions

Sonographische Befunde bei zwei Zwergziegen mit metastasierendem Gallengangskarzinom

In dieser Arbeit werden die Befunde von 2 Zwergziegen mit metastasierendem Gallengangskarzinom beschrieben. Klinisch standen bei der Ziege 1 eine birnenförmige Umfangsvermehrung des Abdomens, bei der Zwergziege 2 Strangurie und Pollakisurie im Vordergrund. Bei beiden Tieren waren die Aktivitäten der Leberenzyme stark erhöht. Bei der sonographischen Untersuchung wurden in der Leber multiple, rundliche, echogene Herde festgestellt, die teilweise von einem echoarmen Randsaum umgeben waren. Aufgrund der sonographischen Befunde wurde die Verdachtsdiagnose einer tumorösen Lebererkrankung gestellt. Die Sektion ergab bei beiden Zwergziegen das Vorliegen eines intrahepatischen Gallengangskarzinoms mit Metastasierung. This case study describes 2 miniature goats with metastatic bile duct carcinoma. The main clinical sign was a pear-shaped abdomen due to abdominal distension in case 1 and stranguria and pollakiuria in case 2. Liver enzyme activity was markedly elevated in both goats, and ultrasonographic examination showed multiple round echoic structures that were partly surrounded by a hypoechoic zone. A tentative diagnosis of liver tumour was made based on the sonographic findings, and a final diagnosis of intrahepatic bile duct carcinoma was made post mortem

Cérémonie de remise des prix Latsis universitaires à Uni Dufour, le 17 octobre 2017. Allocution d'Anne Emery-Torracinta, conseillère d’État.

Cérémonie de remise des prix Latsis universitaires à Uni Dufour, le 17 octobre 2017. Allocution d'Anne Emery-Torracinta, conseillère d’État