The gene coding for benzoate-para-hydroxylase (bphA) of Aspergillus niger was cloned using differential hybridisation techniques and complementation of mutants deficient in this enzyme activity. The nucleotide sequence of the gene was determined, the presence of two introns was shown and the transcription start and termination sites were determined. The structure of the mRNA upstream from the long open reading frame (ORF) is unusual. It contains two small, overlapping ORFs whose function is unknown. Comparison of the deduced amino acid sequence of the protein with the sequences present in the databanks, indicated a significant similarity of BPH to the superfamily of cytochrome P450 enzymes. Further analysis revealed that this protein is a member of a new P450 gene family designated P450LIII. The gene is designated CYP53. To increase the BPH activity of A. niger, multiple copies of the bphA gene were introduced into the genome of a recipient strain by transformation. Although increased intracellular levels of the BPH protein could be detected, the BPH enzyme activity was decreased, suggesting titration of another essential component.

Background A comprehensive medical history is needed to establish and ensure a high standard in dental care; however, it is challenging to draw clinical consequences on the variety of potential diseases and medications, especially for dental students. Aim of this observational study was to investigate, whether undergraduate dental students using an analog anamnesis tool for risk classification would be more confident and have more knowledge in risk classification than other students in the same year of study. Methods A cohort of 48 fifth year dental students was included and allocated into two groups based on their curriculum-related division (group A: n = 25, group B: n = 23). Group A received a teaching event and provision of an analog anamnesis tool for risk classification; group B received neither a teaching event nor the anamnesis tool. At baseline and after two weeks (follow-up), questionnaires regarding self-perceived confidence with risk classification, questions on different disease, medications and lifestyle factors and a task with 15 medical histories of prepared patient cases were applied. The data was statistically analyzed using Mann–Whitney or Wilcoxon test. Results In group comparison of the differences between baseline and follow-up regarding self-perceived confidence, significantly higher improvement was noted in group A compared to group B for all questions (p < 0.05). With regard to knowledge, the group comparison revealed that the differences in all of the four tasks were significantly higher in group A compared to group B (pi ≤ 0.01). Thereby, the different tasks in group A differed between baseline and follow-up as follows: Risk of complications: 49.04 ± 13.59 vs. 67.96 ± 17.22, p < 0.01, Risk of oral diseases: 48.77 ± 13.57 vs. 63.44 ± 16.78, p = 0.01, Indication of antibiotic prophylaxis: 75.70 ± 13.45 vs. 87.97 ± 10.37, p < 0.01 and the Medical history task on 15 patient cases: 58.45 ± 4.74 vs. 71.47 ± 9.54, p < 0.01. Conclusion The applied analog anamnesis tool supported an increase in students´ confidence with issues related to at-risk patients alongside with their knowledge in risk classification. The applied anamnesis tool can be recommended for improving teaching of risk management for undergraduate dental students.

Mass developments of toxic cyanobacteria have increased in frequency due to global warming and eutrophication. Such cyanobacterial blooms impact whole freshwater ecosystems, especially reducing the abundance of herbivory species of the genus Daphnia. These negative effects on Daphnia have frequently been attributed to cyanobacterial secondary metabolites, among them hepatotoxic microcystins and protease inhibitors. Protease inhibitors inhibit major digestive proteases in the gut of Daphnia which results in reduced fitness, that is, population growth. To date evidence for local adaptation of Daphnia to cyanobacteria is confined to microcystin‐producing cyanobacteria and based on comparison of individual clones from different populations but lacks evidence from multiclone microcosm experiments. In the present study, D. magna clones from a Swedish lake where they coexist with the microcystin‐free Microcystis sp. strain BM25 were compared to clones from a Polish population without cyanobacteria, first in single‐clone experiments and subsequently in a multiclonal experimental population. The Swedish clones were assumed to be locally adapted to this protease inhibitor‐producing cyanobacterium and indeed showed higher population growth rates, a proxy for fitness, and dominated the population in the presence of dietary Microcystis sp. BM25, but not in the absence of this cyanobacterium. The results indicate an adaptive tolerance of the Swedish population and point at local adaptation to locally co‐occurring protease inhibitor‐producing cyanobacteria.

Mass developments of toxin-producing cyanobacteria are frequently observed in freshwater ecosystems due to eutrophication and global warming. These mass developments can partly be attributed to cyanobacterial toxins, such as protease inhibitors (PIs), which inhibit digestive serine proteases of Daphnia, the major herbivore of phytoplankton and cyanobacteria. To date, mechanisms of this inhibition in the gut of the crustacean Daphnia magna are not known. Here, we characterize a single serine protease, chymotrypsin 448 (CT448), which is present in the gut of the crustacean D. magna. Sequence alignments with human serine proteases revealed that CT448 has a putative N-terminal pro-peptide which is extended compared to the mammalian homologs and within this pro-peptide two N-linked glycosylation motifs were found. CT448 was heterologously expressed in Sf21 insect cells using a baculovirus expression system for optimized protein production and secretion into the medium. The protein was purified via a one-step affinity chromatography, which resulted in a protein yield of 3.45 mg/l medium. The inactive precursor (zymogen) could be activated by tryptic digestion. This is the first example of a recombinant expression of an active crustacean serine protease, which functions in the gut of a Daphnia. Proteomic identification of protease cleavage sites (PICS) and hydrolysation of various synthetic substrates showed that CT448 is a chymotrypsin-like elastase. In this study, we confirm that CT448 is a target of cyanobacterial protease inhibitors. Local evolutionary modifications of CT448 might render this proteolytic enzyme less susceptible against cyanobacterial secondary metabolites and might improve the fitness of Daphnia during cyanobacterial blooms.

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