Evolutionary alternatives examined with three examples: Amino acids, coiled coils and strategies of iron-cycling bacteria

The questions of why things are the way they are and if they could have been any different are frequently occupying the minds of us human beings. One way out is provided by the assumption of contingency, the view that long-term development is mainly dependent on the results of many random events. However, I argue that from a scientific point of view, fundamentally revolving around skepticism and the search for underlying patterns, contingency does not provide a comfortable answer and should always be perceived as a preliminary resort. This thesis revolves around the investigation of evolutionary alternatives related to case studies at three different levels of biological complexity. Key aspects of evolutionary alternatives are the pool of available elements to choose from, the pressures which lead to the preference for the selection of certain choices over others, and the conditions under which these selections comprise a viable or even optimal choice for the organism(s)

A disulfide bridge in the calcium binding site of a polyester hydrolase increases its thermal stability and activity against polyethylene terephthalate

Elevated reaction temperatures are crucial for the efficient enzymatic degradation of polyethylene terephthalate (PET). A disulfide bridge was introduced to the polyester hydrolase TfCut2 to substitute its calcium binding site. The melting point of the resulting variant increased to 94.7°C (wild-type TfCut2: 69.8 °C) and its half-inactivation temperature to 84.6 °C (TfCut2: 67.3 °C). The variant D204C-E253C-D174R obtained by introducing further mutations at vicinal residues showed a temperature optimum between 75 and 80 °C compared to 65 and 70 °C of the wild-type enzyme. The variant caused a weight loss of PET films of 25.0 +/- 0.8% (TfCut2: 0.3 +/-0.1%) at 70 °C after a reaction time of 48 h. The results demonstrate that a highly efficient and calcium-independent thermostable polyester hydrolase can be obtained by replacing its calcium binding site with a disulfide bridge

Genome-wide study of association and interaction with maternal cytomegalovirus infection suggests new schizophrenia loci

Genetic and environmental components as well as their interaction contribute to the risk of schizophrenia, making it highly relevant to include environmental factors in genetic studies of schizophrenia. This study comprises genome-wide association (GWA) and follow-up analyses of all individuals born in Denmark since 1981 and diagnosed with schizophrenia as well as controls from the same birth cohort. Furthermore, we present the first genome-wide interaction survey of single nucleotide polymorphisms (SNPs) and maternal cytomegalovirus (CMV) infection. The GWA analysis included 888 cases and 882 controls, and the follow-up investigation of the top GWA results was performed in independent Danish (1396 cases and 1803 controls) and German-Dutch (1169 cases, 3714 controls) samples. The SNPs most strongly associated in the single-marker analysis of the combined Danish samples were rs4757144 in ARNTL (P=3.78 × 10 -6) and rs8057927 in CDH13 (P=1.39 × 10 -5). Both genes have previously been linked to schizophrenia or other psychiatric disorders. The strongest associated SNP in the combined analysis, including Danish and German-Dutch samples, was rs12922317 in RUNDC2A (P=9.04 × 10 -7). A region-based analysis summarizing independent signals in segments of 100 kb identified a new region-based genome-wide significant locus overlapping the gene ZEB1 (P=7.0 × 10 -7). This signal was replicated in the follow-up analysis (P=2.3 × 10 -2). Significant interaction with maternal CMV infection was found for rs7902091 (P SNP × CMV =7.

A disulfide bridge in the calcium binding site of a polyester hydrolase increases its thermal stability and activity against polyethylene terephthalate

Elevated reaction temperatures are crucial for the efficient enzymatic degradation of polyethylene terephthalate (PET). A disulfide bridge was introduced to the polyester hydrolase TfCut2 to substitute its calcium binding site. The melting point of the resulting variant increased to 94.7°C (wild-type TfCut2: 69.8 °C) and its half-inactivation temperature to 84.6 °C (TfCut2: 67.3 °C). The variant D204C-E253C-D174R obtained by introducing further mutations at vicinal residues showed a temperature optimum between 75 and 80 °C compared to 65 and 70 °C of the wild-type enzyme. The variant caused a weight loss of PET films of 25.0 +/- 0.8% (TfCut2: 0.3 +/-0.1%) at 70 °C after a reaction time of 48 h. The results demonstrate that a highly efficient and calcium-independent thermostable polyester hydrolase can be obtained by replacing its calcium binding site with a disulfide bridge

A disulfide bridge in the calcium binding site of a polyester hydrolase increases its thermal stability and activity against polyethylene terephthalate

Elevated reaction temperatures are crucial for the efficient enzymatic degradation of polyethylene terephthalate (PET). A disulfide bridge was introduced to the polyester hydrolase TfCut2 to substitute its calcium binding site. The melting point of the resulting variant increased to 94.7°C (wild-type TfCut2: 69.8 °C) and its half-inactivation temperature to 84.6 °C (TfCut2: 67.3 °C). The variant D204C-E253C-D174R obtained by introducing further mutations at vicinal residues showed a temperature optimum between 75 and 80 °C compared to 65 and 70 °C of the wild-type enzyme. The variant caused a weight loss of PET films of 25.0 +/- 0.8% (TfCut2: 0.3 +/-0.1%) at 70 °C after a reaction time of 48 h. The results demonstrate that a highly efficient and calcium-independent thermostable polyester hydrolase can be obtained by replacing its calcium binding site with a disulfide bridge

Importance of cerebrospinal fluid analysis in the era of McDonald 2010 criteria: a German-Austrian retrospective multicenter study in patients with a clinically isolated syndrome

The majority of patients presenting with a first clinical symptom suggestive of multiple sclerosis (MS) do not fulfill the MRI criteria for dissemination in space and time according to the 2010 revision of the McDonald diagnostic criteria for MS and are thus classified as clinically isolated syndrome (CIS). To re-evaluate the utility of cerebrospinal fluid (CSF) analysis in the context of the revised McDonald criteria from 2010, we conducted a retrospective multicenter study aimed at determining the prevalence and predictive value of oligoclonal IgG bands (OCBs) in patients with CIS. Patients were recruited from ten specialized MS centers in Germany and Austria. We collected data from 406 patients; at disease onset, 44/406 (11 %) fulfilled the McDonald 2010 criteria for MS. Intrathecal IgG OCBs were detected in 310/362 (86 %) of CIS patients. Those patients were twice as likely to convert to MS according to McDonald 2010 criteria as OCB-negative individuals (hazard ratio = 2.1, p = 0.0014) and in a shorter time period of 25 months (95 % CI 21-34) compared to 47 months in OCB-negative individuals (95 % CI 36-85). In patients without brain lesions at first attack and presence of intrathecal OCBs (30/44), conversion rate to MS was 60 % (18/30), whereas it was only 21 % (3/14) in those without OCBs. Our data confirm that in patients with CIS the risk of conversion to MS substantially increases if OCBs are present at onset. CSF analysis definitely helps to evaluate the prognosis in patients who do not have MS according to the revised McDonald criteria

Update on the profile of the EUSTAR cohort: an analysis of the EULAR Scleroderma Trials and Research group database

Objectives Systemic sclerosis (SSc) is a rare disease requiring multicentre collaboration to reveal comprehensive details of disease-related causes for morbidity and mortality.Methods The European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) group initiated a database to prospectively gather key data of patients with SSc using a minimal essential dataset that was reorganised in 2008 introducing new items. Baseline visit data of patients who were registered between 2004 and 2011 were analysed using descriptive statistics.Results In June 2011, 7655 patients (2838 with diffuse cutaneous (dc) and 4481 with limited cutaneous (lc) SSc who fulfilled the American College of Rheumatology diagnostic criteria had been registered in 174 centres, mainly European. The most prominent hallmarks of disease were Raynaud's phenomenon (96.3%), antinuclear antibodies (93.4%) and a typical capillaroscopic pattern (90.9%). Scleroderma was more common on fingers and hands than on any other part of the skin. Proton pump inhibitors (65.2%), calcium channel blockers (52.7%), and corticosteroids (45.3%) were most often prescribed. Among the immunosuppressant agents, cyclophosphamide was used more often in dcSSc than in lcSSc.Conclusions The EUSTAR database provides an abundance of information on the true clinical face of SSc that will be helpful in improving the classification of SSc and its subsets and for developing more specific therapeutic recommendations