Processing of Plasmodium falciparum Merozoite Surface Protein MSP1 activates a Spectrin-binding function enabling parasite egress from RBCs

The malaria parasite Plasmodium falciparum replicates within erythrocytes, producing progeny merozoites that are released from infected cells via a poorly understood process called egress. The most abundant merozoite surface protein, MSP1, is synthesized as a large precursor that undergoes proteolytic maturation by the parasite protease SUB1 just prior to egress. The function of MSP1 and its processing are unknown. Here we show that SUB1-mediated processing of MSP1 is important for parasite viability. Processing modifies the secondary structure of MSP1 and activates its capacity to bind spectrin, a molecular scaffold protein that is the major component of the host erythrocyte cytoskeleton. Parasites expressing an inefficiently processed MSP1 mutant show delayed egress, and merozoites lacking surface-bound MSP1 display a severe egress defect. Our results indicate that interactions between SUB1-processed merozoite surface MSP1 and the spectrin network of the erythrocyte cytoskeleton facilitate host erythrocyte rupture to enable parasite egress

Monte Carlo-based Development of a Shield and Total Background Estimation for the COBRA Experiment

The COBRA experiment aims for the measurement of the neutrinoless double beta decay and thus for the determination the effective Majorana mass of the neutrino. To be competitive with other next-generation experiments the background rate has to be in the order of 10e−3 counts/kg/keV/yr, which is a challenging criterion. This thesis deals with the development of a shield design and the calculation of the expected total background rate for the large scale COBRA experiment containing 13824 6cm³ CdZnTe detectors. For the development of a shield single-layer and multi-layer shields were investigated and a shield design was optimized concerning high-energy muon-induced neutrons. As the best design the combination of 10cm boron doped polyethylene as outermost layer, 20cm lead and 10cm copper as innermost layer were determined. It showed the best performance regarding neutron attenuation as well as (n,γ) self-shielding effects leading to a negligible background rate of less than 2·10e−6 counts/kg/keV/yr. Additionally, the shield with a thickness of 40cm is compact and cost- effective. In the next step the expected total background rate was computed taking into account individual setup parts and various background sources including natural and man-made radioactivity,cosmic ray-induced background and thermal neutrons. Furthermore, a comparison of measured data from the COBRA demonstrator setup with Monte Carlo data was usedto calculate reliable contamination levels of the single setup parts. The calculation was performed conservatively to prevent an underestimation. In addition, the contributionto the total background rate regarding the individual detector parts and background sources was investigated. The main portion arise from the Delrin support structure,the Glyptal lacquer followed by the circuit board of the high voltage supply. Most background events originate from α particles with a quantity of 99% in total. Regardingsurface events a contribution of 26.8% was determined. Altogether, a background of less than 54·10e−3 counts/kg/keV/yr was determined showing the potential of the COBRAexperiment

Tetrahydrobiopteryna, kofaktor śródbłonkowej syntazy tlenku azotu, chroni odległe obszary miokardium przed apoptozą po wywołanym doświadczalnie zawale serca w warunkach in vivo

Background: Following myocardial infarction (MI), apoptosis occurs early in the remote myocardium and contributes to the processes of myocardial remodelling. Increased nitrosative stress is a well-known and potent inductor of myocardial apopto¬sis. Excess activation of endothelial nitric oxide synthase (eNOS) increases its uncoupling potential and results in nitrosative stress via formation of peroxynitrite. However, the pathophysiological role of eNOS signalling in the remote myocardium after MI is as yet undefined. Aim: The impact of eNOS activation on pro- and anti-apoptotic signalling in the remote myocardium and the influence of pretreatment with the eNOS cofactor tetrahydrobiopterin (BH4) on eNOS activation, nitrosative stress level, and apoptosis induction and execution were studied in a rat MI model in vivo. Results: Twenty-four hours after anterior MI, eNOS activity in animals treated with left anterior descending coronary artery ligation (LIG) significantly increased in the posterior left ventricular (LV) myocardium as did protein nitrosylation when com¬pared to sham treatment. This was paralleled by induction of apoptosis via the extrinsic and intrinsic pathways. Moreover, anti-apoptotic signalling via protein kinase B/Akt and glycogen synthase-kinase 3 beta was suppressed. Notably, pretreatment with the eNOS cofactor BH4 reduced eNOS activation, prevented excess protein nitrosylation, blunted apoptosis induction, facilitated anti-apoptotic signalling, and eventually prevented apoptosis execution. Conclusions: Here we showed that 24 h after experimental MI in rats in vivo, apoptosis was induced in the posterior non-in¬farcted LV wall. Evidence is presented that pretreatment with the eNOS cofactor BH4 resulted in less nitrosative stress and weakened apoptotic processes, although the stabilisers contained did participate in this phenomenon. Because apoptosis is a crucial component of myocardial remodelling, influencing eNOS signalling might be an interesting pharmacological target for the development of novel anti-remodelling therapies.Wstęp: Apoptoza w odległych rejonach miokardium występuje wcześnie po zawale serca (MI) i przyczynia się do remodelingu mięśnia sercowego. Zwiększenie stresu nitrozacyjnego jest znanym silnym czynnikiem wywołującym apoptozę miokardium. Nadmierna aktywacja śródbłonkowej syntazy tlenku azotu (eNOS) zwiększa jej rozprzęganie i powoduje stres nitrozacyjny w wyniku syntezy peroksynitrytu. Jednak nie poznano dotychczas patofizjologicznej roli eNOS w przesyłaniu sygnałów do odległych rejonów miokardium po MI. Cel: Celem niniejszej pracy było przeanalizowanie wpływu aktywacji eNOS na przekazywanie sygnałów pro- i anty-apop¬tycznych w odległych rejonach miokardium oraz wpływu wstępnego leczenia kofaktorem, tetrahydrobiopteryną (BH4) na aktywację NOS, poziom stresu nitrozacyjnego oraz indukowanie i przebieg apoptozy w szczurzym modelu in vivo zawału serca. Wyniki: Dwadzieścia cztery godziny po zawale ściany przedniej stwierdzono istotne zwiększenie w porównaniu z wartościami obserwowanymi w grupie kontrolnej w zakresie aktywności eNOS w miokardium tylnej ściany lewej komory u zwierząt, u których podwiązano gałąź międzykomorową przednią lewej tętnicy wieńcowej, podobnie jak w przypadku nitrozylacji białek. Jednocześnie zaobserwowano indukcję apoptozy zarówno w mechanizmie zewnątrz-, jak i wewnątrzpochodnym. Ponadto zahamowane zostało przekazywanie sygnałów anty-apoptotycznych za pośrednictwem ścieżki sygnałowej kinazy proteinowej B/Akt i kinazy syntazy glikogenu 3 beta. Warto zaznaczyć, że podanie wcześniej kofaktora eNOS, BH4, zmniejszyło aktywację eNOS, zapobiegło nadmiernej nitrozylacji białek, stłumiło indukcję apoptozy, ułatwiło przekazywanie sygnałów anty-apoptotycznych i zatrzymało proces apoptozy. Wnioski: Wykazano, że 24 godziny po wywołanym eksperymentalnie MI u szczurów in vivo nastąpiła indukcja apoptozy w tylnej ścianie lewej komory nieobjętej zawałem. Przedstawiono dowody naukowe potwierdzające, że wcześniejsze podanie kofaktora eNOS, BH4, spowodowało zmniejszenie stresu nitrozacyjnego i osłabienie procesów apoptozy, chociaż zawarte w nim stabilizatory miały w tym swój udział. Ze względu na to, że apoptoza jest ważnym elementem remodelingu miokar¬dium, oddziaływanie na ścieżkę sygnałową eNOS może być interesującym celem leczenia w opracowywaniu nowych terapii przeciwdziałających remodelingowi

Cell cycle, oncogenic and tumor suppressor pathways regulate numerous long and macro non-protein-coding RNAs

Background: The genome is pervasively transcribed but most transcripts do not code for proteins, constituting non-protein-coding RNAs. Despite increasing numbers of functional reports of individual long non-coding RNAs (lncRNAs), assessing the extent of functionality among the non-coding transcriptional output of mammalian cells remains intricate. In the protein-coding world, transcripts differentially expressed in the context of processes essential for the survival of multicellular organisms have been instrumental in the discovery of functionally relevant proteins and their deregulation is frequently associated with diseases. We therefore systematically identified lncRNAs expressed differentially in response to oncologically relevant processes and cell-cycle, p53 and STAT3 pathways, using tiling arrays. Results: We found that up to 80% of the pathway-triggered transcriptional responses are non-coding. Among these we identified very large macroRNAs with pathway-specific expression patterns and demonstrated that these are likely continuous transcripts. MacroRNAs contain elements conserved in mammals and sauropsids, which in part exhibit conserved RNA secondary structure. Comparing evolutionary rates of a macroRNA to adjacent protein-coding genes suggests a local action of the transcript. Finally, in different grades of astrocytoma, a tumor disease unrelated to the initially used cell lines, macroRNAs are differentially expressed. Conclusions: It has been shown previously that the majority of expressed non-ribosomal transcripts are non-coding. We now conclude that differential expression triggered by signaling pathways gives rise to a similar abundance of non-coding content. It is thus unlikely that the prevalence of non-coding transcripts in the cell is a trivial consequence of leaky or random transcription events

A mass casualty incident of infectious diseases at the port of Hamburg: an analysis of organizational structures and emergency concepts

Background!#!The project 'ARMIHN' (Adaptive Resiliency Management in Port) focuses on strengthening the capability to act in a mass casualty incident (MCI) due to an outbreak of infectious diseases (MCI-ID). In addition to the current threat from the COVID-19 pandemic and associated outbreaks on cruise ships, previous MCI-ID were especially caused by pathogens such as Influenza virus or Norovirus. The first step was, to get an overview of processes and resources using the example of the Port of Hamburg, and to show the associated interaction of involved parties. This will serve as a basis for developing an operational strategy and offers the opportunity to optimize current work processes.!##!Methods!#!A selective literature research using specified key words was performed and existing MCI concepts were received from local authorities. Identified structures and processes were analyzed in a multiple step process and also brought together through discussions in workshops with involved organizations and other experts. Additionally, the distances between the nearest rescue stations and selected hospitals from the Port of Hamburg were analyzed.!##!Results!#!The current available concepts are proven, but an adaptation to an MCI-ID shows opportunities for a further cross-organizational development. The organizational structure of an MCI-ID in the Port of Hamburg was described, including a large number of involved organizations (n = 18). There are 17 involved fire and rescue stations and the port can be reached from these locations within 6 to 35 min. Based on their specialist expertise, 14 of the 31 listed clinics were selected.!##!Conclusion!#!The purpose of the study was to provide an analysis of the current situation and show how involved parties would cope an MCI. A description of processes and resources at the Port of Hamburg will be used when designing a management plan for responding to an MCI-ID