Untersuchungen des Effektes vom Licht und reaktiven Sauerstoffspezies auf Archaea in humanen Hautproben

Ammoniak oxidierende Archaea (AOA) machen bis zu 1 % des Mikrobioms der menschlichen Haut aus und spielen möglicherweise eine Rolle für die Hautgesundheit, in dem ein saures Mileu erhalten wird, und Immunreaktionen durch diese Organismen ausgelöst werden können. Bisher wurden zwar mehrere Studien zur Funktion und Interaktion mit dem menschlichen Körper durchgeführt, jedoch wurde in keiner früheren Studie die Wirkung einer medizinischen Behandlung auf diese Mikroorganismen untersucht.In dieser Arbeit sollte die Wirkung des von Repuls R7-rtbl erzeugten Lichts auf die Archaea der menschlichen Haut in Photobiomodulationsbehandlungen in vitro untersucht werden. Zu diesem Zweck wurde das Ammoniak oxidierende Archaeon Nitrososphaera viennensis bei allen Wellenlängen bestrahlt, die von Repuls R7-rtbl bereitgestellt werden. Darüber hinaus wurde in dieser Studie die Auswirkungen der durch photodynamische Therapie (PDT) erzeugten reaktiven Sauerstoffspezies auf das Wachstum von N. viennensis und Nitrosocosmicus franklandianus untersucht, Dies geschah unter Verwendung von Methylenblau als Photosensibilisator.Die Ergebnisse unterstützten die Hypothese der AOA-Photoinhibition durch Licht, wobei N. viennensis durch tägliche Bestrahlung für 2 Stunden mit kontinuierlichem blauem Licht (433 [nm], 342 [μE/m2.s]) und teilweise durch kontinuierliches violettes Licht (rot 635 [nm] + blau 433 [nm] bei 931[μE/m2.s]) gehemmt wurde. Im Gegensatz dazu hatten das pulsierende und das kontinuierliche rote Licht 635 [nm] bei 744 [μE/m2.s] keinen Einfluss auf das Zellwachstum.Die Forschungsergebnisse aus den PDT-Experimenten zeigten, dass N. viennensis die PDT mit 20 [μM] Methylenblau (MB) nicht überstehen konnte, wohl aber mit 8 [μM] MB. Interessanterweise überlebte N. franklandianus die PDT mit (2, 5, 8, 20 [μM]) MB, wenn Natriumpyruvat im Medium enthalten war, während der Organismus ohne Natriumpyruvat die PDT mit 8 und 20 [μM]) MB nicht überlebte.Ammonia oxidizing archaea (AOA) constitute up to 1% of the human skin microbiome and play a possible role in skin health by maintaining an acidic milieu and triggering immune responses. Several studies were performed to understand their function and interaction with the host environment, however, no previous study has investigated the effect of medical treatment on these microorganisms.In this thesis, we aimed to investigate the effect of the light produced by a Repuls R7-rtbl device on the human skin archaea during photobiomodulation treatment in vitro. For this goal, the ammonia-oxidizing archaeon Nitrosospharea viennensis was irradiated with different wavelengths provided by Repuls R7-rtbl and the effect on the growth was monitored. Moreover, this study attempted to discover the effect of reactive oxygen species produced by the photodynamic therapy (PDT) on N. viennensis and Nitrosocosmicus franklandianus using methylene blue as a photosensitizer in vitro.The results supported the hypothesis, that AOA are sensitive to photoinhibition by light. N. viennensis was inhibited by daily irradiation for 2 hours with continuous blue light (433 [nm], 342 [μE/m2.s]) and partially by continuous violet light (red 635 [nm] + blue 433 [nm] at 931 [μE/m2.s]). In contrast, pulsing and continuous red lights 635 [nm] at 744 [μE/m2. s] had no effect on cell growth.The results from the PDT experiments showed that N. viennensis could not survive the PDT with 20 [μM] methylene blue (MB), but tolerated it 8 [μM]. Interestingly, N. franklandianus survived the PDT with (2, 5, 8, 20 [μM]) MB when sodium pyruvate was included in the medium, whereas without sodium pyruvate it could not survive the PDT with 8 and 20 [μM]) MB

Analysis of biomass productivity and physiology of Nitrososphaera viennensis grown in continuous culture

Microbial ammonia oxidation is the first and usually rate limiting step in nitrification and is therefore an important step in the global nitrogen cycle. Ammonia-oxidizing archaea (AOA) play an important role in nitrification. Here, we report a comprehensive analysis of biomass productivity and the physiological response of Nitrososphaera viennensis to different ammonium and carbon dioxide (CO2) concentrations aiming to understand the interplay between ammonia oxidation and CO2 fixation of N. viennensis. The experiments were performed in closed batch in serum bottles as well as in batch, fed-batch, and continuous culture in bioreactors. A reduced specific growth rate (μ) of N. viennensis was observed in batch systems in bioreactors. By increasing CO2 gassing μ could be increased to rates comparable to that of closed batch systems. Furthermore, at a high dilution rate (D) in continuous culture (≥ 0.7 of μmax) the biomass to ammonium yield (Y(X/NH3)) increased up to 81.7% compared to batch cultures. In continuous culture, biofilm formation at higher D prevented the determination of Dcrit. Due to changes in Y(X/NH3) and due to biofilm, nitrite concentration becomes an unreliable proxy for the cell number in continuous cultures at D towards μmax. Furthermore, the obscure nature of the archaeal ammonia oxidation prevents an interpretation in the context of Monod kinetics and thus the determination of KS. Our findings indicate that the physiological response of N. viennensis might be regulated with different enzymatic make-ups, according to the ammonium catalysis rate. We reveal novel insights into the physiology of N. viennensis that are important for biomass production and the biomass yield of AOA. Moreover, our study has implications to the field of archaea biology and microbial ecology by showing that bioprocess technology and quantitative analysis can be applied to decipher environmental factors affecting the physiology and productivity of AOA.</jats:p

Data_Sheet_1_Analysis of biomass productivity and physiology of Nitrososphaera viennensis grown in continuous culture.docx

Microbial ammonia oxidation is the first and usually rate limiting step in nitrification and is therefore an important step in the global nitrogen cycle. Ammonia-oxidizing archaea (AOA) play an important role in nitrification. Here, we report a comprehensive analysis of biomass productivity and the physiological response of Nitrososphaera viennensis to different ammonium and carbon dioxide (CO2) concentrations aiming to understand the interplay between ammonia oxidation and CO2 fixation of N. viennensis. The experiments were performed in closed batch in serum bottles as well as in batch, fed-batch, and continuous culture in bioreactors. A reduced specific growth rate (μ) of N. viennensis was observed in batch systems in bioreactors. By increasing CO2 gassing μ could be increased to rates comparable to that of closed batch systems. Furthermore, at a high dilution rate (D) in continuous culture (≥ 0.7 of μmax) the biomass to ammonium yield (Y(X/NH3)) increased up to 81.7% compared to batch cultures. In continuous culture, biofilm formation at higher D prevented the determination of Dcrit. Due to changes in Y(X/NH3) and due to biofilm, nitrite concentration becomes an unreliable proxy for the cell number in continuous cultures at D towards μmax. Furthermore, the obscure nature of the archaeal ammonia oxidation prevents an interpretation in the context of Monod kinetics and thus the determination of KS. Our findings indicate that the physiological response of N. viennensis might be regulated with different enzymatic make-ups, according to the ammonium catalysis rate. We reveal novel insights into the physiology of N. viennensis that are important for biomass production and the biomass yield of AOA. Moreover, our study has implications to the field of archaea biology and microbial ecology by showing that bioprocess technology and quantitative analysis can be applied to decipher environmental factors affecting the physiology and productivity of AOA.</p

Hyaluronic Acid Induction Promotes the Differentiation of Human Neural Crest-like Cells into Periodontal Ligament Stem-like Cells

Periodontal ligament (PDL) stem-like cells (PDLSCs) are promising for regeneration of the periodontium because they demonstrate multipotency, high proliferative capacity, and the potential to regenerate bone, cementum, and PDL tissue. However, the transplantation of autologous PDLSCs is restricted by limited availability. Since PDLSCs are derived from neural crest cells (NCs) and NCs persist in adult PDL tissue, we devised to promote the regeneration of the periodontium by activating NCs to differentiate into PDLSCs. SK-N-SH cells, a neuroblastoma cell line that reportedly has NC-like features, seeded on the extracellular matrix of PDL cells for 2 weeks, resulted in the significant upregulation of PDL marker expression. SK-N-SH cell-derived PDLSCs (SK-PDLSCs) presented phenotypic characteristics comparable to induced pluripotent stem cell (iPSC)-derived PDLSCs (iPDLSCs). The expression levels of various hyaluronic acid (HA)-related genes were upregulated in iPDLSCs and SK-PDLSCs compared with iPSC-derived NCs and SK-N-SH cells, respectively. The knockdown of CD44 in SK-N-SH cells significantly inhibited their ability to differentiate into SK-PDLSCs, while low-molecular HA (LMWHA) induction enhanced SK-PDLSC differentiation. Our findings suggest that SK-N-SH cells could be applied as a new model to induce the differentiation of NCs into PDLSCs and that the LMWHA–CD44 relationship is important for the differentiation of NCs into PDLSCs

Pancreatic surgery outcomes: multicentre prospective snapshot study in 67 countries

Background: Pancreatic surgery remains associated with high morbidity rates. Although postoperative mortality appears to have improved with specialization, the outcomes reported in the literature reflect the activity of highly specialized centres. The aim of this study was to evaluate the outcomes following pancreatic surgery worldwide. Methods: This was an international, prospective, multicentre, cross-sectional snapshot study of consecutive patients undergoing pancreatic operations worldwide in a 3-month interval in 2021. The primary outcome was postoperative mortality within 90 days of surgery. Multivariable logistic regression was used to explore relationships with Human Development Index (HDI) and other parameters. Results: A total of 4223 patients from 67 countries were analysed. A complication of any severity was detected in 68.7 per cent of patients (2901 of 4223). Major complication rates (Clavien–Dindo grade at least IIIa) were 24, 18, and 27 per cent, and mortality rates were 10, 5, and 5 per cent in low-to-middle-, high-, and very high-HDI countries respectively. The 90-day postoperative mortality rate was 5.4 per cent (229 of 4223) overall, but was significantly higher in the low-to-middle-HDI group (adjusted OR 2.88, 95 per cent c.i. 1.80 to 4.48). The overall failure-to-rescue rate was 21 per cent; however, it was 41 per cent in low-to-middle- compared with 19 per cent in very high-HDI countries. Conclusion: Excess mortality in low-to-middle-HDI countries could be attributable to failure to rescue of patients from severe complications. The authors call for a collaborative response from international and regional associations of pancreatic surgeons to address management related to death from postoperative complications to tackle the global disparities in the outcomes of pancreatic surgery (NCT04652271; ISRCTN95140761)

Pancreatic surgery outcomes: multicentre prospective snapshot study in 67 countries

Background: Pancreatic surgery remains associated with high morbidity rates. Although postoperative mortality appears to have improved with specialization, the outcomes reported in the literature reflect the activity of highly specialized centres. The aim of this study was to evaluate the outcomes following pancreatic surgery worldwide.Methods: This was an international, prospective, multicentre, cross-sectional snapshot study of consecutive patients undergoing pancreatic operations worldwide in a 3-month interval in 2021. The primary outcome was postoperative mortality within 90 days of surgery. Multivariable logistic regression was used to explore relationships with Human Development Index (HDI) and other parameters.Results: A total of 4223 patients from 67 countries were analysed. A complication of any severity was detected in 68.7 percent of patients (2901 of 4223). Major complication rates (Clavien-Dindo grade at least IIIa) were 24, 18, and 27 percent, and mortality rates were 10, 5, and 5 per cent in low-to-middle-, high-, and very high-HDI countries respectively. The 90-day postoperative mortality rate was 5.4 per cent (229 of 4223) overall, but was significantly higher in the low-to-middle-HDI group (adjusted OR 2.88, 95 per cent c.i. 1.80 to 4.48). The overall failure-to-rescue rate was 21 percent; however, it was 41 per cent in low-to-middle-compared with 19 per cent in very high-HDI countries.Conclusion: Excess mortality in low-to-middle-HDI countries could be attributable to failure to rescue of patients from severe complications. The authors call for a collaborative response from international and regional associations of pancreatic surgeons to address management related to death from postoperative complications to tackle the global disparities in the outcomes of pancreatic surgery (NCT04652271; ISRCTN95140761)