Title of the PhD thesis
Breaking down Barriers: Understanding the Role of Anaerobic Bacteria in the Skin

Description
Atopic eczema (AE) is an inflammatory skin disorder that is increasing in prevalence (Williams H., et al. 2008; Asher MI., et al. 2006). Most of the research done on this topic has focused on the disturbance of the aerobic microbial layer above the stratum corneum, but inflammation may be caused by the loss of anaerobic microbes lying beneath that skin layer (Nakatsuji T, et al 2013).  The stratum corneum is fractured in patients with AE, and this allows oxygen to reach and disrupt the environment where the anaerobic bacteria live (Tabata N, et al 1998; Nakatsuji, T et al 2013). It has been shown that skin microbiome diversity is lower in AE patients, and the diversity is significantly lower in perforated skin than with it intact. Though this change might solely result from an increase in S. aureus, it also implies the possibility that the size of the anaerobic microbiome may be drastically reduced, which indeed may be the cause of AE (Gong J, et al 2006; Reiger M, et al 2016). Anaerobic bacteria are known to have pH reducing metabolites, such as short chain fatty acids, and, compared to the healthy controls, in AE patients the skin pH is increased (Jang et al 2015).  In this project, we aim to isolate, characterize, and define the role of anaerobic bacteria in the skin, and to determine their relationship to the development of AE.

Title of the PhD thesis
Nutritional interventions controlling brown adipose tissue activity

Description
Brown adipose tissue (BAT) is the main site of non-shivering thermogenesis in mammals. Heat produced by BAT upon adrenergic stimulation is essential for the survival of small rodents and hibernators in a cold environment, but also contributes to diet-induced thermogenesis. Uncoupling protein 1 (UCP1) is ubiquitously expressed in the inner membrane of BAT mitochondria and mediates the uncoupling of fuel consumption from ATP production to dissipate energy as heat. Since BAT has a crucial role in energy balance regulation, ongoing research emphasizes its therapeutic potential to battle the global epidemics of obesity and type 2 diabetes. The recent discovery of functional BAT in healthy adults has raised great interest in increasing energy expenditure by enhancing BAT thermogenesis. Previous pharmacological approaches targeting BAT through sympathomimetics have failed due to detrimental cardiovascular side effects. We aim to identify novel nutritional interventions either mediating the activation of brown fat by non-sympathetic pathways, or facilitating the endogenous sympathetic activation.

Title of the PhD thesis
Enteroendocrine cells and regulation of feeding behavior

Description
Enteroendocrine cells (EECs) are a key component of the gut epithelium. They interact with the external gut environment and play an active role in the homeostasis of the animal. They release different molecules, from neuropeptides to hormones, that affect their immediate surroundings or travel along the animal to reach distal regions. EECs can respond to a variety of stimuli, such as food presence in the gut, integrity of the epithelium and the composition of the microbiota, by expression of different receptors. However, whether and how EECs modulate animal behavior, such as feeding related decisions, has not been studied at sufficient detail, although it could have broad implications in behavior and metabolism.

Title of the PhD Thesis
Assessment of microbiota in small niches by sequencing

Description
Routinely, modern high-throughput sequencing is used to identify bacteria within feces or skin samples by their 16S rRNA genes. Small niches, for example crypts or mucus of the gut, are of greater interest as focus points for bacteria-host interactions. In this project, methods are developed to assess the microbial communities even if small numbers of bacteria are present. Furthermore, 16S rRNA sequencing is improved to gain higher resolution for species determination.

Publications

• Hücker SM, Vanderhaeghen S, Abellan-Schneyder I, Scherer S, Neuhaus K (2018). The novel anaerobiosis-responsive overlapping gene ano is overlapping antisense to the annotated gene ECs2385 of Escherichia coli O157:H7 Sakai. Front Microbiol. 9:931.
• Hücker SM, Vanderhaeghen S, Abellan-Schneyder I, Wecko R, Simon S, Scherer S, Neuhaus K (2018). A novel short L-arginine responsive protein-coding gene (laoB) antiparallel overlapping to a CadC-like transcriptional regulator in Escherichia coli O157:H7 Sakai originated by overprinting. BMC Evol Biol. 18(1):21.