Modularity and integration in the skull of canis lupus (Linnaeus 1758): a geometric morphometrics study on domestic dogs and wolves

Domestic dogs stand out due to an enormous morphological variation of their skulls, which clearly surpasses the variation found in wolves. A frequent phenomenon among this variation is the occurrence of disproportions between skull modules which appear much more frequent and more pronounced in domestic dogs than in wolves. This phenomenon led up to the hypothesis that the integration of the skull modules in domestic dogs is degraded when compared to the wolf. Moreover, it was hypothesized that the patterns of covariation of skull modules were altered through artificial selection. In a first study, this hypothesis was tested using geometric morphometrics on 196 CT scanned dog and wolf skulls. The results point to an unchanged integration strength of the skull modules in domestic dogs. Also the covariation pattern of skull modules is very similar to that of wolves. Through this surprising result, the hypothesis for a second study was formed. The temporomandibular joint of dogs is highly diverse when compared to the joint of wolves. The reasons for this phenomenon have not been explored before. If the high integration in the domestic dog skull does also apply to the temporomandibular joint, the shape of the joint should be predictable on the basis of skull geometry. Also this hypothesis was tested using geometric morphometrics with a sample of 274 CT scanned skulls. The results showed that certain characteristics of the temporomandibular joint can be traced back to overall skull geometry (foremost relative muzzle length, skull flexion and size). Exceptions from this pattern are frequent though, and dogs with very similar skulls can have differently formed jaw joints. This points to a certain degree of structural independence of the jaw joint from the rest of the skull. The observed covariation patterns closely resemble patterns found in primates and humans, other carnivores and even pigeons, which suggests a highly conserved developmental program

Molecular architecture of the human protein deacetylase Sirt1 and its regulation by AROS and resveratrol

Sirtuins are NAD+-dependent protein deacetylases regulating metabolism, stress responses and ageing processes. Among the seven mammalian Sirtuins, Sirt1 is the physiologically best-studied isoform. It regulates nuclear functions such as chromatin remodelling and gene transcription, and it appears to mediate beneficial effects of a low calorie diet which can partly be mimicked by the Sirt1 activating polyphenol resveratrol. The molecular details of Sirt1 domain architecture and regulation, however, are little understood. It has a unique N-terminal domain and CTD (C-terminal domain) flanking a conserved Sirtuin catalytic core and these extensions are assumed to mediate Sirt1-specific features such as homo-oligomerization and activation by resveratrol. To analyse the architecture of human Sirt1 and functions of its N- and C-terminal extensions, we recombinantly produced Sirt1 and Sirt1 deletion constructs as well as the AROS (active regulator of Sirt1) protein. We then studied Sirt1 features such as molecular size, secondary structure and stimulation by small molecules and AROS. We find that Sirt1 is monomeric and has extended conformations in its flanking domains, likely disordered especially in the N-terminus, resulting in an increased hydrodynamic radius. Nevertheless, both termini increase Sirt1 deacetylase activity, indicating a regulatory function. We also find an unusual but defined conformation for AROS protein, which fails, however, to stimulate Sirt1. Resveratrol, in contrast, activates the Sirt1 catalytic core independent of the terminal domains, indicating a binding site within the catalytic core and suggesting that small molecule activators for other isoforms might also exist

Personalarbeit im demografischen Wandel: eine Befragung kleiner und mittlerer Unternehmen der Gesundheitswirtschaft und der maritimen Wirtschaft in Norddeutschland

Im Rahmen des Verbundprojekts „PerDemo – Personalarbeit im demografischen Wandel“ wurde eine telefonische Befragung von Personalverantwortlichen in Unternehmen durchgeführt. Es sollte herausgefunden werden, inwieweit sich kleine und mittlere Unternehmen (KMU) der Gesundheitswirtschaft und der maritimen Wirtschaft in den norddeutschen Bundesländern Schleswig-Holstein, Hamburg und Mecklenburg-Vorpommern mit den Herausforderungen des demografischen Wandels konfrontiert sehen und welche Maßnahmen zur Bewältigung und Gestaltung des demografischen Wandels auf betrieblicher Ebene bereits umgesetzt werden. Gleichzeitig sollte ermittelt werden, inwieweit ein Zusammenhang zwischen dem Alter der Belegschaften und der betrieblichen Innovationsfähigkeit besteht

Rediscovery of the Conus conspersus Reeve, 1844 holotype

Fenzan, William J., Dublanka, Mario, Curth, Stefan (2022): Rediscovery of the Conus conspersus Reeve, 1844 holotype. Zootaxa 5154 (4): 496-500, DOI: https://doi.org/10.11646/zootaxa.5154.4.