Nitric oxide and proteoglycan biosynthesis by human articular chondrocytes in alginate culture

AbstractInterleukin-1α and β induced the production of large amounts of nitric oxide by normal, human articular chondrocytes in alginate culture; at the same time the biosynthesis of proteoglycan was strongly suppressed. In a dose-dependent manner, NG-monomethyl-l-arginine both inhibited nitric oxide formation and relieved the suppression of proteoglycan synthesis. However concentrations of NG-monomethyl-l-arginine which completely prevented nitric oxide production only partially restored proteoglycan biosynthesis, even at low doses of interleukin-1 where suppression of proteoglycan synthesis was modest. The organic donor of nitric oxide, S-nitrosyl-acetyl-d,l- penicillamine also inhibited proteoglycan biosynthesis, but not as extensively as interleukin-1. These data suggest that interleukin-1 suppresses synthesis of the cartilaginous matrix through more than one mechanism, at least one of which is dependent upon the production of nitric oxide

Digital quantum simulation of spin models with circuit quantum electrodynamics

Systems of interacting quantum spins show a rich spectrum of quantum phases and display interesting many-body dynamics. Computing characteristics of even small systems on conventional computers poses significant challenges. A quantum simulator has the potential to outperform standard computers in calculating the evolution of complex quantum systems. Here, we perform a digital quantum simulation of the paradigmatic Heisenberg and Ising interacting spin models using a two transmon-qubit circuit quantum electrodynamics setup. We make use of the exchange interaction naturally present in the simulator to construct a digital decomposition of the model-specific evolution and extract its full dynamics. This approach is universal and efficient, employing only resources which are polynomial in the number of spins and indicates a path towards the controlled simulation of general spin dynamics in superconducting qubit platforms.Comment: 12 pages, 9 figure

Age-Dependent Dissimilarity of the Nasopharyngeal and Middle Ear Microbiota in Children With Acute Otitis Media.

Acute bacterial otitis media is usually caused by otopathogens ascending to the middle ear from the nasopharynx (NP). However, it is unknown if the nasopharyngeal microbiota of children with acute otitis media (AOM) can serve as an age-dependent or independent proxy for the microbial communities of the middle ear fluid (MEF) as there is a lack of 16S rRNA amplicon sequencing studies simultaneously analyzing the microbial communities of the two sites. Within this study, we performed 16S rRNA next generation sequencing on a total of 286 nasopharyngeal swabs (NPSs) collected between 2004 and 2013 within a Swiss national AOM surveillance program from children (0-6 years) with AOM. In addition, 42/286 children had spontaneous tympanic membrane perforation and, therefore, those MEF could also be analyzed. We found that alpha [Richness, Shannon diversity index (SDI) and Evenness] and beta diversity measurements of the nasopharyngeal bacterial microbiota showed a clear dependency of the increasing age of the children. In more detail, bacterial richness and personalized profiles (measured by beta dispersion) were higher and more frequent in older children, respectively. Dissimilarity values based on the binary distance matrix of the microbiota patterns of the NP and the MEF also correlated with increasing age. In general, positive (PPV) and negative predictive values (NPV) of the most abundant operational taxonomic units (OTUs) in the NP were moderately and well predictive for their presence in the MEF, respectively. This data is crucial to better understand polymicrobial infections and therefore AOM pathogenesis

Reusability of filtering facepiece respirators after decontamination through drying and germicidal UV irradiation.

During pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators. Disposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm <sup>2</sup> after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10-300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests. No viable phage particles were recovered from any of the respirators after decontamination (log reduction in virus titre >3), and no reduction in chemical or physical properties (SEM, particle penetrations <5%-6%) were observed. Increasing the UVGI dose 10-fold led to chemical alterations of the respirator filtration media (FTIR) but did not affect the physical properties (particle penetration), which was unaltered even at 3000 mJ/cm <sup>2</sup> (50 cycles). When respirators had been used by healthcare workers and undergone decontamination, they had particle penetration significantly greater than never donned respirators. This decontamination procedure is an attractive method for respirators in case of shortages during a SARS pandemic. A successful implementation requires a careful design and particle penetration performance control tests over the successive reuse cycles

Reference materials (RMs) for analysis of the human factor II (prothrombin) gene G20210A mutation

The Scientific Committee of Molecular Biology Techniques (C-MBT) in Clinical Chemistry of the IFCC has initiated a joint project in co-operation with the European Commission, Joint Research Centre, Institute of Reference Materials and Measurements to develop and produce plasmid-type reference materials (RMs) for the analysis of the human prothrombin gene G20210A mutation. Although DNA tests have a high impact on clinical decision-making and the number of tests performed in diagnostic laboratories is high, issues of quality and quality assurance exist, and currently only a few RMs for clinical genetic testing are available. A gene fragment chosen was produced that spans all primer annealing sites published to date. Both the wild-type and mutant alleles of this gene fragment were cloned into a pUC18 plasmid and two plasmid RMs were produced. In addition, a mixture of both plasmids was produced to mimic the heterozygous genotype. The present study describes the performance of these reference materials in a commutability study, in which they were tested by nine different methods in 13 expert laboratories. This series of plasmid RMs are, to the best of our knowledge, the first plasmid-type clinical genetic RMs introduced worldwid

Sperm competition-induced plasticity in the speed of spermatogenesis

Background: Sperm competition between rival ejaculates over the fertilization of ova typically selects for the production of large numbers of sperm. An obvious way to increase sperm production is to increase testis size, and most empirical work has focussed on this parameter. Adaptive plasticity in sperm production rate could also arise due to variation in the speed with which each spermatozoon is produced, but whether animals can respond to relevant environmental conditions by modulating the kinetics of spermatogenesis in this way has not been experimentally investigated. Results: Here we demonstrate that the simultaneously hermaphroditic flatworm Macrostomum lignano exhibits substantial plasticity in the speed of spermatogenesis, depending on the social context: worms raised under higher levels of sperm competition produce sperm faster. Conclusions: Our findings overturn the prevailing view that the speed of spermatogenesis is a static property of a genotype, and demonstrate the profound impact that social environmental conditions can exert upon a key developmental process. We thus identify, to our knowledge, a novel mechanism through which sperm production rate is maximised under sperm competition

Palmitoylation mediates membrane association of hepatitis E virus ORF3 protein and is required for infectious particle secretion.

Hepatitis E virus (HEV) is a positive-strand RNA virus encoding 3 open reading frames (ORF). HEV ORF3 protein is a small, hitherto poorly characterized protein involved in viral particle secretion and possibly other functions. Here, we show that HEV ORF3 protein forms membrane-associated oligomers. Immunoblot analyses of ORF3 protein expressed in cell-free vs. cellular systems suggested a posttranslational modification. Further analyses revealed that HEV ORF3 protein is palmitoylated at cysteine residues in its N-terminal region, as corroborated by 3H-palmitate labeling, the investigation of cysteine-to-alanine substitution mutants and treatment with the palmitoylation inhibitor 2-bromopalmitate (2-BP). Abrogation of palmitoylation by site-directed mutagenesis or 2-BP treatment altered the subcellular localization of ORF3 protein, reduced the stability of the protein and strongly impaired the secretion of infectious particles. Moreover, selective membrane permeabilization coupled with immunofluorescence microscopy revealed that HEV ORF3 protein is entirely exposed to the cytosolic side of the membrane, allowing to propose a model for its membrane topology and interactions required in the viral life cycle. In conclusion, palmitoylation determines the subcellular localization, membrane topology and function of HEV ORF3 protein in the HEV life cycle

A microfluidics-based method for measuring neuronal activity in Drosophila chemosensory neurons

Monitoring neuronal responses to defined sensory stimuli is a powerful and widely used approach for understanding sensory coding in the nervous system. However, providing precise, stereotypic and reproducible cues while concomitantly recording neuronal activity remains technically challenging. Here we describe the fabrication and use of a microfluidics system that allows precise temporally restricted stimulation of Drosophila chemosensory neurons with an array of different chemical cues. The system can easily be combined with genetically encoded calcium sensors, and it can measure neuronal activity at single-cell resolution in larval sense organs and in the proboscis or leg of the adult fly. We describe the design of the master mold, the production of the microfluidic chip and live imaging using the calcium sensor GCaMP, expressed in distinct types of Drosophila chemosensory neurons. Fabrication of the master mold and microfluidic chips requires basic skills in photolithography and takes ~2 weeks; the same devices can be used repeatedly over several months. Flies can be prepared for measurements in minutes and imaged for up to 1 h

Intra-specific variation of sperm length in the malaria vector Anopheles gambiae: males with shorter sperm have higher reproductive success

<p>Abstract</p> <p>Background</p> <p>Intra-specific variation in sperm length influences male reproductive success in several species of insects. In males of the malaria vector <it>Anopheles gambiae</it>, sperm length is highly variable but the significance of this variation is unknown. Understanding what determines the reproductive success of male mosquitoes is critical for controlling malaria, and in particular for replacing natural populations with transgenic, malaria-resistant mosquitoes.</p> <p>Methods</p> <p>A laboratory population of <it>A. gambiae </it>males was tested for intra-specific variation in sperm length. A full-sib quantitative genetic design was used to test for a genetic component of sperm length in <it>A. gambiae </it>males and estimate its heritability. This study also tested for a relationship between sperm length and male reproductive success in <it>A. gambiae</it>. Male reproductive success was measured as the proportions of inseminated and ovipositing females.</p> <p>Results</p> <p>There was intra-specific variation of sperm length in <it>A. gambiae</it>. There was no significant genetic variation in sperm length and its heritability was low (h²= 0.18) compared to other insects. Sperm length was correlated with male body size (measured as wing length). Males with short sperm had significantly higher reproductive success than males with long sperm and this was independent of body size.</p> <p>Conclusion</p> <p>This is the first study to demonstrate intra-specific variation in sperm length in <it>A. gambiae </it>and that males with short sperm have higher reproductive success. That sperm length influences female oviposition is important for any strategy considering the release of transgenic males.</p