Impact of Protein Aggregates on Sporulation and Germination of Bacillus subtilis

In order to improve our general understanding of protein aggregate (PA) management and impact in bacteria, different model systems and processes need to be investigated. As such, we developed an inducible synthetic PA model system to investigate PA dynamics in the Gram-positive model organism Bacillus subtilis. This confirmed previous observations that PA segregation in this organism seems to follow the Escherichia coli paradigm of nucleoid occlusion governing polar localization and asymmetric segregation during vegetative growth. However, our findings also revealed that PAs can readily persist throughout the entire sporulation process after encapsulation in the forespore during sporulation. Moreover, no deleterious effects of PA presence on sporulation, germination and spore survival against heat or UV stress could be observed. Our findings therefore indicate that the sporulation process is remarkably robust against perturbations by PAs and misfolded proteins.

Tuning riboflavin derivatives for photodynamic inactivation of pathogens

The development of effective pathogen reduction strategies is required due to the rise in antibiotic-resistant bacteria and zoonotic viral pandemics. Photodynamic inactivation (PDI) of bacteria and viruses is a potent reduction strategy that bypasses typical resistance mechanisms. Naturally occurring riboflavin has been widely used in PDI applications due to efficient light-induced reactive oxygen species (ROS) release. By rational design of its core structure to alter (photo)physical properties, we obtained derivatives capable of outperforming riboflavin's visible light-induced PDI against E. coli and a SARS-CoV-2 surrogate, revealing functional group dependency for each pathogen. Bacterial PDI was influenced mainly by guanidino substitution, whereas viral PDI increased through bromination of the flavin. These observations were related to enhanced uptake and ROS-specific nucleic acid cleavage mechanisms. Trends in the derivatives' toxicity towards human fibroblast cells were also investigated to assess viable therapeutic derivatives and help guide further design of PDI agents to combat pathogenic organisms.

[Morbus Behçet or inflammatory bowel disease--a diagnostic and therapeutic dilemma]

We present the case of a 43-year old caucasian male suffering from a condition initially diagnosed as colitis ulcerosa. For 2 years Azathioprine and anti-TNF-alpha antibodies were used for treatment without convincing benefit but with serious adverse events. After the first occurrence of complex accompanying symptoms like oral and scrotal ulcerations, arthritis and scratch-induced skin lesions the differential diagnosis of a Morbus Adamantiades-Behçet with intestinal evolvement was considered. After introduction of a parenteral Ciclosporin medication, which was later switched to Tacrolimus and Azathioprin, a remission could be achieved that lasted for several months. When a drug-induced acute kidney injury occurred, the regime was changed to Golimumab and a delayed but significant improvement was achieved. To separate Morbus Adamantiades-Behçet from inflammatory bowel disease is of some difficulty, demands interdisciplinary cooperation and is the basis for a successful therapy.