Multilocus Sequence Typing von Borrelia burgdorferi sensu stricto und Borrelia afzelii Stämmen aus Europa und den USA: Populationsstruktur, Pathogenität und Patientensymptomatik

To understand the epidemiological and ecological context of vector borne diseases, precise typing of causative agents is necessary. Multilocus sequence typing (MLST) is a method in molecular biology for the fast, economic and unambiguous characterization of bacteria and other organisms. Lyme borreliosis (LB) is the most common tick borne disease in the Northern hemisphere caused by species of the Borrelia burgdorferi sensu lato complex. To better understand the epidemiological and clinical context of two Borrelia species frequently reported in LB, 133 Borrelia (B.) burgdorferi sensu stricto (s. s.) and Borrelia (B.) afzelii strains from patients and ticks in Europe were typed via MLST. MLST data from additional 744 B. burgdorferi s. s. and B. afzelii strains were downloaded from the MLST data bank. The population structure, clinical manifestations and human pathogenicity of B. afzelii in Europe as well as B. burgdorferi s. s. in Europe and the USA were compared. In addition, the invasiveness of sequence types (ST) and clonal complexes (CC) were analyzed in both species. Special attention was paid to the clinical manifestation of neuroborreliosis. Analysis of the population structure confirmed the hypothesis that B. afzelii shows a greater heterogeneity of ST (98 ST from n = 198 strains) compared to B. burgdorferi s. s. (112 ST from n = 677 strains). Moreover there was a greater prevalence of B. afzelii (ticks: 41.3 %, patients: 52.7 %) than B. burgdorferi s. s. (ticks: 13.2 %, patients: 13.7 %) in Europe. B. burgdorferi s. s. populations from Europe and the USA showed an overlap of two sequence types (ST1 and ST3) in patient isolates while there was no overlap of STs in ticks. Thus, it was hypothesized that the patients in Europe carrying ST1 or ST3 may have acquired their infection in the USA. B. burgdorferi s. s. infections in Europe were found to be more often associated with disseminated symptoms (93 %) and neuroborreliosis (odds ratio: 3.0) than B. afzelii infections (42 %) in Europe and B. burgdorferi s. s. infections in the USA (42 %), respectively it was noticed that some ST and CC might have greater human pathogenity than others (cf. ST1, ST3 and CC4 in Hanincova et al. 2013). Modern typing systems have already generated a huge data base for bacterial analyses. Nevertheless, further studies based on our data would be required to verify the differences of ST and CC in human pathogenicity and to get appropriate statistical data about differences of ST in Europe and the USA. In this context, our data can be relevant for further vaccine development

Multilocus Sequence Typing von Borrelia burgdorferi sensu stricto und Borrelia afzelii Stämmen aus Europa und den USA: Populationsstruktur, Pathogenität und Patientensymptomatik

To understand the epidemiological and ecological context of vector borne diseases, precise typing of causative agents is necessary. Multilocus sequence typing (MLST) is a method in molecular biology for the fast, economic and unambiguous characterization of bacteria and other organisms. Lyme borreliosis (LB) is the most common tick borne disease in the Northern hemisphere caused by species of the Borrelia burgdorferi sensu lato complex. To better understand the epidemiological and clinical context of two Borrelia species frequently reported in LB, 133 Borrelia (B.) burgdorferi sensu stricto (s. s.) and Borrelia (B.) afzelii strains from patients and ticks in Europe were typed via MLST. MLST data from additional 744 B. burgdorferi s. s. and B. afzelii strains were downloaded from the MLST data bank. The population structure, clinical manifestations and human pathogenicity of B. afzelii in Europe as well as B. burgdorferi s. s. in Europe and the USA were compared. In addition, the invasiveness of sequence types (ST) and clonal complexes (CC) were analyzed in both species. Special attention was paid to the clinical manifestation of neuroborreliosis. Analysis of the population structure confirmed the hypothesis that B. afzelii shows a greater heterogeneity of ST (98 ST from n = 198 strains) compared to B. burgdorferi s. s. (112 ST from n = 677 strains). Moreover there was a greater prevalence of B. afzelii (ticks: 41.3 %, patients: 52.7 %) than B. burgdorferi s. s. (ticks: 13.2 %, patients: 13.7 %) in Europe. B. burgdorferi s. s. populations from Europe and the USA showed an overlap of two sequence types (ST1 and ST3) in patient isolates while there was no overlap of STs in ticks. Thus, it was hypothesized that the patients in Europe carrying ST1 or ST3 may have acquired their infection in the USA. B. burgdorferi s. s. infections in Europe were found to be more often associated with disseminated symptoms (93 %) and neuroborreliosis (odds ratio: 3.0) than B. afzelii infections (42 %) in Europe and B. burgdorferi s. s. infections in the USA (42 %), respectively it was noticed that some ST and CC might have greater human pathogenity than others (cf. ST1, ST3 and CC4 in Hanincova et al. 2013). Modern typing systems have already generated a huge data base for bacterial analyses. Nevertheless, further studies based on our data would be required to verify the differences of ST and CC in human pathogenicity and to get appropriate statistical data about differences of ST in Europe and the USA. In this context, our data can be relevant for further vaccine development

The carbon concentrating mechanism in Chlamydomonas reinhardtii: Finding the missing pieces

The photosynthetic, unicellular green alga, Chlamydomonas reinhardtii, lives in environments that often contain low concentrations of CO2 and HCO3-, the utilizable forms of inorganic carbon (Ci). C. reinhardtii possesses a carbon concentrating mechanism (CCM) which can provide suitable amounts of Ci for growth and development. This CCM is induced when the CO2 concentration is at air levels or lower and is comprised of a set of proteins that allow the efficient uptake of Ci into the cell as well as its directed transport to the site where Rubisco fixes CO2 into biomolecules. While several components of the CCM have been identified in recent years, the picture is still far from complete. To further improve our knowledge of the CCM, we undertook a mutagenesis project where an antibiotic resistance cassette was randomly inserted into the C. reinhardtii genome resulting in the generation of 22,000 mutants. The mutant collection was screened using both a published PCR-based approach (Gonzalez-Ballester et al. 2011) and a phenotypic growth screen. The PCR-based screen did not rely on a colony having an altered growth phenotype and was used to identify colonies with disruptions in genes previously identified as being associated with the CCM-related gene. Eleven independent insertional mutations were identified in eight different genes showing the usefulness of this approach in generating mutations in CCM-related genes of interest as well as identifying new CCM components. Further improvements of this method are also discussed. © 2014 Springer Science+Business Media Dordrecht

Trans-Atlantic exchanges have shaped the population structure of the Lyme disease agent Borrelia burgdorferi sensu stricto

The origin and population structure of Borrelia burgdorferi sensu stricto (s.s.), the agent of Lyme disease, remain obscure. This tick-transmitted bacterial species occurs in both North America and Europe. We sequenced 17 European isolates (representing the most frequently found sequence types in Europe) and compared these with 17 North American strains. We show that trans-Atlantic exchanges have occurred in the evolutionary history of this species and that a European origin of B. burgdorferi s. s. is marginally more likely than a USA origin. The data further suggest that some European human patients may have acquired their infection in North America. We found three distinct genetically differentiated groups: i) the outgroup species Borrelia bissettii, ii) two divergent strains from Europe, and iii) a group composed of strains from both the USA and Europe. Phylogenetic analysis indicated that different genotypes were likely to have been introduced several times into the same area. Our results demonstrate that irrespective of whether B. burgdorferi s. s. originated in Europe or the USA, later trans-Atlantic exchange(s) have occurred and have shaped the population structure of this genospecies. This study clearly shows the utility of next generation sequencing to obtain a better understanding of the phylogeography of this bacterial species

COVID-19-Impfung senkt das Risiko für Infektion, schwere Krankheitsverläufe und Tod

Im Mai 2021 kam es in einem Alten- und Pflegeheim in der Oberpfalz zu einem SARS-CoV-2-Aus-bruch mit einer hohen Anzahl von Impfdurchbrüchen, woraufhin serologische Untersuchungen und epidemiologische Daten der Bewohnerinnen und Bewohner und dem Pflegepersonal ausgewertet wurden. Ziel dieser Untersuchung war es, das Risiko von Hospitalisierung und Tod bei Geimpften im Vergleich zu Ungeimpften darzustellen.Peer Reviewe

Effects of microcompartmentation on flux distribution and metabolic pools in Chlamydomonas reinhardtii chloroplasts

Cells and organelles are not homogeneous but include microcompartments that alter the spatiotemporal characteristics of cellular processes. The effects of microcompartmentation on metabolic pathways are however difficult to study experimentally. The pyrenoid is a microcompartment that is essential for a carbon concentrating mechanism (CCM) that improves the photosynthetic performance of eukaryotic algae. Using Chlamydomonas reinhardtii, we obtained experimental data on photosynthesis, metabolites, and proteins in CCM-induced and CCM-suppressed cells. We then employed a computational strategy to estimate how fluxes through the Calvin-Benson cycle are compartmented between the pyrenoid and the stroma. Our model predicts that ribulose-1,5-bisphosphate (RuBP), the substrate of Rubisco, and 3-phosphoglycerate (3PGA), its product, diffuse in and out of the pyrenoid, respectively, with higher fluxes in CCM-induced cells. It also indicates that there is no major diffusional barrier to metabolic flux between the pyrenoid and stroma. Our computational approach represents a stepping stone to understanding microcompartmentalized CCM in other organisms

Influenza matrix protein M1

Die Aufklärung der Prozesse, die zur Zusammensetzung des Influenza A Virus führen, ist Bestandteil für die Bekämpfung dieser Infektionskrankheit. Der Viruspartikel setzt sich aus einer Hülle, der darunter liegenden Matrix und dem Genom zusammen. Das Genom ist als Bündel aus acht Ribunucleoproteinkomplexen organisiert. Die Hülle besteht aus einer Membran, die mit Sphingomyelin und Cholesterol angereichert ist und den darin eingebetteten Membranproteinen Hämagglutinin, Neuraminidase und dem Protonenkanal M2. Die unter der Hülle liegende Matrix wird von einem einzigen Influenzaprotein formiert: Dem Matrixprotein M1. Es spielt eine Schlüsselrolle im Replikationszyklus des Virus in der Zelle. Es interagiert mit dem genetischen Material, mit den Membranproteinen und der Lipidmembran der Hülle. Die vorliegende Arbeit gibt Auskunft, welche Lipide eine Rolle in der M1-MembranWechselwirkung spielen. Die Liste der identifizierten Lipide umfasst neben dem bereits bekannten Phosphatidylserin auch Phosphatidylglycerol und Phosphatidsäure. Verschiedene Phosphatidylinositole konnten ebenfalls identifiziert werden. Als stärkster M1 Bindungspartner trat dabei Phosphatidylinositol-4-Phosphat zutage. Weitere auf Mutanten basierende Untersuchungen zeigten, dass der membranbindende Bereich nicht auf eine einzelne Domäne in M1 festgelegt werden kann. Die N-terminale M1-Domäne mit ihrem Oberflächen-exponierten, positiv geladenen Areal und die C-terminale Domäne interagierten mit Modellmembranen. Das Resultat dieser Interaktionen konnte mittels mikroskopischer Untersuchungen an gigantischen unilamellaren Vesikeln dokumentiert werden. Für M1 und für eine Mutante, die nur aus der N-terminalen M1-Domäne besteht, konnte eine von anderen viralen Proteinen unabhängige homooligomere Organisation auf der Membran gezeigt werden. Diese M1-Cluster könnten während der Zusammensetzung des Viruspartikels als Fundament für die Eingliederung aller weiteren viralen Komponenten dienen.about the assembly process of the influenza A virus particle is essential for the development of effective approaches for prevention and treatment of this virus infection. The virus particle consists of an envelope, an underlying matrix, and the encapsulated genome. The genetic material is organized as bundle of eight ribonucleoprotein complexes that encode for eleven proteins. The envelope consists of a lipid bilayer that is enriched in sphingomyelin and cholesterol. The viral spike proteins, hemagglutinin and neuraminidase, as well as the proton channel M2 are embedded into this membrane. The matrix can be found below the envelope. It is formed by one single protein, the matrix protein M1. M1 plays a crucial role during the replication of the virus in the cell. It interacts with the genetic material, with the envelope proteins and with the lipid bilayer of the envelope. The results of this study reveal in detail which lipids are targeted by M1. The set of identified lipids contains phosphatylglycerol and phosphatidic acids as new binding partners, beside the known phophatidylserine. Additionally, several phosphatidylinositols were identified. Phosphatidylinositol-4-phosphate was the strongest binding partner from this group. Mutant-based analysis revealed that M1 owns more than one membrane binding site. The positively charged area in the N-terminal and the C-terminal domain mediated membrane association of the respective mutant protein. The final constitution of M1 on the membrane was characterized by confocal fluorescence microscopy on giant unilamellar vesicles. Full length M1 and a mutant that consisted only of the N-terminal part of M1 showed lateral clustering of homooligomers on the vesicle surface. The clusters formed independently of any other viral component. A function as fundament for the incorporation of the other viral components can be assumed for these clusters

Detection of the new SARS-CoV-2 variants of concern B.1.1.7 and B.1.351 in five SARS-CoV-2 rapid antigen tests (RATs), Germany, March 2021.

SARS-CoV-2 variants of concern (VOC) should not escape molecular surveillance. We investigated if SARS-CoV-2 rapid antigen tests (RATs) could detect B.1.1.7 and B.1.351 VOCs in certain laboratory conditions. Infectious cell culture supernatants containing B.1.1.7, B.1.351 or non-VOC SARS-CoV-2 were respectively diluted both in DMEM and saliva. Dilutions were analysed with Roche, Siemens, Abbott, nal von minden and RapiGEN RATs. While further studies with appropriate real-life clinical samples are warranted, all RATs detected B.1.1.7 and B.1.351, generally comparable to non-VOC strain

Members of a small family of nodulin-like genes are regulated under iron deficiency in roots of Arabidopsis thaliana

The analysis of rapid responses in the transcriptome of Arabidopsis roots to a decreased iron (Fe) supply was studied using DNA microarrays and revealed candidate genes with putative roles in Fe homeostasis. In addition to the frequently reported induction of gene activity in response to Fe deficiency, the expression of a number of putative cationic metal transporters was found to rapidly decrease in response to Fe deficiency. In this report we have investigated a small family of five nodulin-like genes that show protein sequence similarity to AtVIT1 and likely have a function in regulation of Fe homeostasis. DNA microarray analysis showed a rapid decrease in transcript abundance for nodulin-like1 (At1g21140), nodulin-like2 (At1g76800), and nodulin-like21 (At3g25190). This decrease was significant after 6 h of Fe deficiency and persisted at least to 72 h. Nodulin-like3 (At3g43630) and Nodulin-like4 (At3g43660) did not respond to the Fe concentration in the microarray analysis. The nodulin-like family encoded presumptive membrane proteins with five calculated transmembrane domains, and all members had significant protein sequence homology to the vacuolar Fe transporters AtVIT1 and ScCCC1p. Homologs of all five nodulin-like genes were found in both di- and monocotyledon plants, as well as in Physcomitrella and Chlamydomonas. Promoter-beta-glucuronidase (GUS) assays showed expression of the nodulin-like1 gene in roots, hypocotyls, and expanded cotyledons of two-week-old Arabidopsis seedlings with the greatest activity associated with the vascular bundle and the root stele. In the absence of Fe, GUS activity was greatly reduced and was only weakly visible in the stele and vascular bundle. In an attempt to identify the function of these nodulin-like proteins, we isolated knockout mutants for nodulin-like3 and nodulin-like21 from available T-DNA insertion lines. Although these mutants did not show dramatic changes in growth or in their ability to grow on Fe-deficient media or media containing from 5 to 120 mu M Fe, the nodulin-like3 mutant had a significantly higher Fe concentration in the shoots and both nodulin-like3 and nodulin-like21 mutants had significantly decreased Fe in the roots. These results were taken as an indication, that some members of this nodulin-like family were directly involved in Fe homeostasis in plants. (C) 2011 Elsevier Masson SAS. All rights reserved