PPTC7 antagonizes mitophagy by promoting BNIP3 and NIX degradation via SCFFBXL4.

Mitophagy must be carefully regulated to ensure that cells maintain appropriate numbers of functional mitochondria. The SCFFBXL4 ubiquitin ligase complex suppresses mitophagy by controlling the degradation of BNIP3 and NIX mitophagy receptors, and FBXL4 mutations result in mitochondrial disease as a consequence of elevated mitophagy. Here, we reveal that the mitochondrial phosphatase PPTC7 is an essential cofactor for SCFFBXL4-mediated destruction of BNIP3 and NIX, suppressing both steady-state and induced mitophagy. Disruption of the phosphatase activity of PPTC7 does not influence BNIP3 and NIX turnover. Rather, a pool of PPTC7 on the mitochondrial outer membrane acts as an adaptor linking BNIP3 and NIX to FBXL4, facilitating the turnover of these mitophagy receptors. PPTC7 accumulates on the outer mitochondrial membrane in response to mitophagy induction or the absence of FBXL4, suggesting a homoeostatic feedback mechanism that attenuates high levels of mitophagy. We mapped critical residues required for PPTC7-BNIP3/NIX and PPTC7-FBXL4 interactions and their disruption interferes with both BNIP3/NIX degradation and mitophagy suppression. Collectively, these findings delineate a complex regulatory mechanism that restricts BNIP3/NIX-induced mitophagy.

Targeted Preparation and NMR Spectroscopic Characterization of Lys11-Linked Ubiquitin Trimers.

Ubiquitylation refers to the attachment of mono- or poly-ubiquitin molecules to a substrate protein. To shield ubiquitin chains against potential hydrolysis, a facile, click-chemistry based approach was recently established for the generation of site-specifically conjugated ubiquitin dimers relying on triazole-linkage. Here, the preparation of such ubiquitin chains was advanced by the generation of homotypic Lys11-linked ubiquitin trimers considering an isotopic labeling scheme in a moiety-wise manner. The structural and dynamical impact on the ubiquitin unit at proximal, central, or distal position that is potentially invoked by the respective other two moieties was systematically probed by heteronuclear high-resolution NMR spectroscopic approaches. As a result, conjugating a third ubiquitin moiety to the proximal or distal site of a ubiquitin dimer does not alter structural and dynamical characteristics as it has been seen for ubiquitin dimers. This observation suggests that recognition of a homotypically assembled ubiquitin chain by a potential substrate is primarily done by screening the length of a ubiquitin chain rather than relying on subtle changes in structure or dynamic properties of single ubiquitin moieties composing the chain.

Biochemical and Structural Consequences of NEDD8 Acetylation.

Similar to ubiquitin, the ubiquitin-like protein NEDD8 is not only conjugated to other proteins but is itself subject to posttranslational modifications including lysine acetylation. Yet, compared to ubiquitin, only little is known about the biochemical and structural consequences of site-specific NEDD8 acetylation. Here, we generated site-specifically mono-acetylated NEDD8 variants for each known acetylation site by genetic code expansion. We show that, in particular, acetylation of K11 has a negative impact on the usage of NEDD8 by the NEDD8-conjugating enzymes UBE2M and UBE2F and that this is likely due to electrostatic and steric effects resulting in conformational changes of NEDD8. Finally, we provide evidence that p300 acts as a position-specific NEDD8 acetyltransferase.

Jacobian-free variational method for computing connecting orbits in nonlinear dynamical systems.

One approach for describing spatiotemporal chaos is to study the unstable invariant sets embedded in the chaotic attractor of the system. While equilibria, periodic orbits, and invariant tori can be computed using existing methods, the numerical identification of heteroclinic and homoclinic connections between them remains challenging. We propose a robust matrix-free variational method for computing connecting orbits between equilibrium solutions. Instead of a common shooting-based approach, we view the identification of a connecting orbit as a minimization problem in the space of smooth curves in the state space that connect the two equilibria. In this approach, the deviation of a connecting curve from an integral curve of the vector field is penalized by a non-negative cost function. Minimization of the cost function deforms a trial curve until, at a global minimum, a connecting orbit is obtained. The method has no limitation on the dimension of the unstable manifold at the origin equilibrium and does not suffer from exponential error amplification associated with time-marching a chaotic system. Owing to adjoint-based minimization techniques, no Jacobian matrices need to be constructed. Therefore, the memory requirement scales linearly with the size of the problem, allowing the method to be applied to high-dimensional dynamical systems. The robustness of the method is demonstrated for the one-dimensional Kuramoto-Sivashinsky equation.

Predicting chaotic statistics with unstable invariant tori.

It has recently been speculated that long-time average quantities of hyperchaotic dissipative systems may be approximated by weighted sums over unstable invariant tori embedded in the attractor, analogous to equivalent sums over periodic orbits, which are inspired by the rigorous periodic orbit theory and which have shown much promise in fluid dynamics. Using a new numerical method for converging unstable invariant two-tori in a chaotic partial differential equation (PDE), and exploiting symmetry breaking of relative periodic orbits to detect those tori, we identify many quasiperiodic, unstable, invariant two-torus solutions of a modified Kuramoto-Sivashinsky equation. The set of tori covers significant parts of the chaotic attractor and weighted averages of the properties of the tori-with weights computed based on their respective stability eigenvalues-approximate average quantities for the chaotic dynamics. These results are a step toward exploiting higher-dimensional invariant sets to describe general hyperchaotic systems, including dissipative spatiotemporally chaotic PDEs.

Sediment Soot Radiocarbon Indicates that Recent Pollution Controls Slowed Fossil Fuel Emissions in Southeastern China.

Fossil fuel (FF) combustion emissions account for a large, but uncertain, amount of the soot in the atmosphere, play an important role in climate change, and adversely affect human health. However, historical estimates of FF contributions to air pollution are limited by uncertainties in fuel usage and emission factors. Here, we constrained FF soot emissions from southeastern China over the past 110 years, based on a novel radiocarbon method applied to sedimentary soot. The reconstructed soot accumulations reflect the integrated effects of increased FF use caused by economic development and reductions in emissions due to pollution controls. A sharp increase in FF soot started in 1950 as southeastern China industrialized and developed economically, but decreased FF soot fluxes in recent years suggest that pollution controls reduced soot emissions. We compare FF soot history to changes in CO2 emissions, industrial and economic activities, and pollution controls and show that FF soot fluxes are more readily controlled than atmospheric CO2. Our independent FF soot record provides insights into the effects of economic development and controls on air pollution and the environmental impacts from the changes in soot emissions.

Invariant tori in dissipative hyperchaos.

One approach to understand the chaotic dynamics of nonlinear dissipative systems is the study of non-chaotic yet dynamically unstable invariant solutions embedded in the system's chaotic attractor. The significance of zero-dimensional unstable fixed points and one-dimensional unstable periodic orbits capturing time-periodic dynamics is widely accepted for high-dimensional chaotic systems, including fluid turbulence, while higher-dimensional invariant tori representing quasiperiodic dynamics have rarely been considered. We demonstrate that unstable 2-tori are generically embedded in the hyperchaotic attractor of a dissipative system of ordinary differential equations; tori can be numerically identified via bifurcations of unstable periodic orbits and their parameteric continuation and characterization of stability properties are feasible. As higher-dimensional tori are expected to be structurally unstable, 2-tori together with periodic orbits and equilibria form a complete set of relevant invariant solutions on which to base a dynamical description of chaos.

Multipath lens for eye-safe optical wireless communications.

This article considers the design and use of multipath lenses (MPLs) for optical wireless communications (OWC). The MPL increases the maximum permissible exposure (MPE) for eye safety and allows for an increase of transmission power of small-sized emitters like laser diodes (LDs). A prototype of a freeform MPL has been fabricated and characterized. The MPL allows an increase of the optical transmission power by 13 dB, which corresponds to an improvement in the maximum range by a factor of 4.5. The lens transforms the elliptical emission pattern of an edge-emitting LD into a rectangular field-of-view (FOV) with homogenous power distribution. The transmission efficiency through the MPL is 0.905.

Complement regulation in tenocytes under the influence of leukocytes in an indirect co-culture model.

INTRODUCTION: The present in vitro study was undertaken to learn about the effects of leukocytes on tenocytes in respect to complement regulation simulating an inflammatory scenario of the traumatized tissue. METHODS: Human hamstring tendon-derived tenocyte monolayers were co-cultured indirectly with human leukocytes (either Peripheral Blood Mononuclear Cells [PBMCs] or neutrophils) using a transwell system with/without (+ /wo) 10 ng/ml tumor necrosis factor α (TNFα) for 4 and 24 h. Tenocyte and leukocyte cell survival was assessed by live-dead assay. Tenocyte gene expression of TNFα, the anaphylatoxin receptor C5aR and the cytoprotective complement regulatory proteins (CRP) CD46, CD55 and CD59 was monitored using qPCR. TNFα was detected in the culture supernatants using ELISA. RESULTS: C5aR gene expression was significantly induced by TNFα after 4 h, but impaired in the presence of leukocytes + TNFα after 24 h. At 4 h, PBMCs activated by TNFα induced the CRP CD46 gene expression. However, CD55 was significantly suppressed after 24 h by neutrophils + /woTNFα. Leukocytes activated by TNFα decreased also significantly the gene expression of the more downstream acting CRP CD59 after 4 h. TNFα gene expression and ELISA analysis revealed an amplified TNFα expression/release in tenocyte co-cultures with PBMC + /woTNFα, probably contributing to complement regulation. CONCLUSION: TNFα might represent a crucial soluble mediator exerting diverse time-dependent effects on tenocyte complement regulation.

Nondestructive Prediction of the Buckling Load of Imperfect Shells.

From soda cans to space rockets, thin-walled cylindrical shells are abundant, offering exceptional load carrying capacity at relatively low weight. However, the actual load at which any shell buckles and collapses is very sensitive to imperceptible defects and cannot be predicted, which challenges the of such structures. Consequently, probabilistic descriptions in terms of empirical design rules are used and designing reliable structures requires the use of conservative strength estimates. We introduce a nonlinear description where finite-amplitude perturbations trigger buckling. Drawing from the analogy between imperfect shells which buckle and imperfect pipe flow which becomes turbulent, we experimentally show that lateral probing of cylindrical shells reveals their strength nondestructively. A new ridge-tracking method is applied to commercial cylinders with a hole showing that when the location where buckling nucleates is known we can accurately predict the buckling load of each individual shell, within ±5%. Our study provides a new promising framework to understand shell buckling, and more generally, imperfection-sensitive instabilities.

Pain Response to Open Label Placebo in Induced Acute Pain in Healthy Adult Males.

BACKGROUND: Open label placebos with patient education are effective in reducing chronic pain, and recent studies on their effect on pain have established interest in this field. Nevertheless, data on their effect on acute pain are scarce, and on hyperalgesia and allodynia, absent. This study assessed the effect of open label placebos on acute pain in healthy adult males and the influence of placebo education. METHODS: Thirty-two healthy males were included in this prospective, randomized, assessor-blinded crossover, single-center study assessing pain intensities (via numeric rating scale), area of hyperalgesia (von Frey filament), and allodynia (dry cotton swab) in a pain model utilizing intracutaneous electrical stimulation. The authors compared the effect of intravenous open label placebo on pain compared to no treatment. The authors further examined the effect of placebo on hyperalgesia and allodynia, and the influence of education (short vs. detailed) before placebo application. Saliva cortisol concentrations were also measured. RESULTS: Pain ratings (median, first to third quartile) were 21% lower during placebo treatment compared to no treatment, 4.0 (3.2 to 4.9) versus 5.1 (4.7 to 5.4), respectively (P = 0.001). The areas of hyperalgesia and allodynia were lower during placebo treatment compared to no treatment (hyperalgesia, 30 cm [17 to 47] vs. 55 cm [42 to 68], P = 0.003; allodynia, 24 cm [11 to 39] vs. 45 cm [31 to 62], P = 0.007). This corresponds to reductions of 47%. The extent of placebo education had no effect on pain. Saliva cortisol decreased significantly over time and was under the limit of detectability in the majority of participants in postbaseline measurements in both treatment branches. Baseline cortisol was not associated with the placebo effect or strength applied of current to reach defined pain ratings. CONCLUSIONS: Open label placebos might play a role in multimodal analgesic concepts.

High-Resolution Historical Record of Plant Protection Product Deposition Documented by Target and Nontarget Trend Analysis in a Swiss Lake under Anthropogenic Pressure.

A multiproxy workflow was used to assess >60 plant protection products (PPPs) in sediment samples from a Swiss lake under heavy agricultural pressure. The results show the appearance of PPPs for the first time in the early 1960s with an overall detection of 34 PPPs and with herbicides and fungicides found in equal proportions. Paleolimnological data [e.g., chronology, hyperspectral imaging of sedimentary green pigments, and semiquantitative elemental composition (µXRF scans)] suggest that PPP concentrations and fluxes to the sediment over time are not related to land surface processes such as soil erosion or lake biogeochemistry but are attributed mainly to PPP application (inferred from sales) or regulatory measures (bans). Additional compounds with similar sources of contamination as the target PPPs captured by nontarget trend analysis (≥2000 unknown profiles) reveal significant inputs of contaminants to the lake starting in the 1970s, followed by a decrease of contamination at the beginning of the 1990s and a constant increase by ∼28% of the unknown compounds since the year 2000. An ecological risk assessment conducted on detected PPPs indicates that since the 1980s, the sediment quality is insufficient with risk quotient values displaying maximum levels in the most recent sediments (∼2010) despite bans of specific PPPs and environmental regulations.

Uremic Toxins and Ciprofloxacin Affect Human Tenocytes In Vitro.

Tendinopathy is a rare but serious complication of quinolone therapy. Risk factors associated with quinolone-induced tendon disorders include chronic kidney disease accompanied by the accumulation of uremic toxins. Hence, the present study explored the effects of the representative uremic toxins phenylacetic acid (PAA) and quinolinic acid (QA), both alone and in combination with ciprofloxacin (CPX), on human tenocytes in vitro. Tenocytes incubated with uremic toxins +/- CPX were investigated for metabolic activity, vitality, expression of the dominant extracellular tendon matrix (ECM) protein type I collagen, cell-matrix receptor ß1-integrin, proinflammatory interleukin (IL)-1ß, and the ECM-degrading enzyme matrix metalloproteinase (MMP)-1. CPX, when administered at high concentrations (100 mM), suppressed tenocyte metabolism after 8 h exposure and at therapeutic concentrations after 72 h exposure. PAA reduced tenocyte metabolism only after 72 h exposure to very high doses and when combined with CPX. QA, when administered alone, led to scarcely any cytotoxic effect. Combinations of CPX with PAA or QA did not cause greater cytotoxicity than incubation with CPX alone. Gene expression of the pro-inflammatory cytokine IL-1ß was reduced by CPX but up-regulated by PAA and QA. Protein levels of type I collagen decreased in response to high CPX doses, whereas PAA and QA did not affect its synthesis significantly. MMP-1 mRNA levels were increased by CPX. This effect became more pronounced in the form of a synergism following exposure to a combination of CPX and PAA. CPX was more tenotoxic than the uremic toxins PAA and QA, which showed only distinct suppressive effects.

[Opioid crisis: What now? A pain specialist's point of view]. / Die Opioid Krise ­ was nun?

Opioid crisis: What now? A pain specialist's point of view Abstract. In acute pain, opioids in combination with co-analgesics can be useful and indicated. It is important to evaluate and to treat every single patient individually. Therefore, experienced patient guidance is crucial in pain treatment to reduce the risk of side effects and inappropriate long-term opioid use. The indication and doses for opioids need continuous re-evaluation. Ineffective treatments with opioids have to be tapered. Furthermore, opioid prescription should always be limited in time with a plan to taper it to prevent misuse or even addiction. Alternative medical and non-medical treatment options are important as well. The following text gives advice on how to approach a patient with pain and contains a manual on how to handle opioids in different settings.

Magnetization Dynamics of an Individual Single-Crystalline Fe-Filled Carbon Nanotube.

The magnetization dynamics of individual Fe-filled multiwall carbon-nanotubes (FeCNT), grown by chemical vapor deposition, are investigated by microresonator ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) microscopy and corroborated by micromagnetic simulations. Currently, only static magnetometry measurements are available. They suggest that the FeCNTs consist of a single-crystalline Fe nanowire throughout the length. The number and structure of the FMR lines and the abrupt decay of the spin-wave transport seen in BLS indicate, however, that the Fe filling is not a single straight piece along the length. Therefore, a stepwise cutting procedure is applied in order to investigate the evolution of the ferromagnetic resonance lines as a function of the nanowire length. The results show that the FeCNT is indeed not homogeneous along the full length but is built from 300 to 400 nm long single-crystalline segments. These segments consist of magnetically high quality Fe nanowires with almost the bulk values of Fe and with a similar small damping in relation to thin films, promoting FeCNTs as appealing candidates for spin-wave transport in magnonic applications.

Expanding the DOPA Universe with Genetically Encoded, Mussel-Inspired Bioadhesives for Material Sciences and Medicine.

Catechols are a biologically relevant group of aromatic diols that have attracted much attention as mediators of adhesion of "bio-glue" proteins in mussels of the genus Mytilus. These organisms use catechols in the form of the noncanonical amino acid l-3,4-dihydroxyphenylalanine (DOPA) as a building block for adhesion proteins. The DOPA is generated post-translationally from tyrosine. Herein, we review the properties, natural occurrence, and reactivity of catechols in the design of bioinspired materials. We also provide a basic description of the mussel's attachment apparatus, the interplay between its different molecules that play a crucial role in adhesion, and the role of post-translational modifications (PTMs) of these proteins. Our focus is on the microbial production of mussel foot proteins with the aid of orthogonal translation systems (OTSs) and the use of genetic code engineering to solve some fundamental problems in the bioproduction of these bioadhesives and to expand their chemical space. The major limitation of bacterial expression systems is their intrinsic inability to introduce PTMs. OTSs have the potential to overcome these challenges by replacing canonical amino acids with noncanonical ones. In this way, PTM steps are circumvented while the genetically programmed precision of protein sequences is preserved. In addition, OTSs should enable spatiotemporal control over the complex adhesion process, because the catechol function can be masked by suitable chemical protection. Such caged residues can then be noninvasively unmasked by, for example, UV irradiation or thermal treatment. All of these features make OTSs based on genetic code engineering in reprogrammed microbial strains new and promising tools in bioinspired materials science.

Artificially Linked Ubiquitin Dimers Characterised Structurally and Dynamically by NMR Spectroscopy.

As one of the most prevalent post-translational modifications in eukaryotic cells, ubiquitylation plays vital roles in many cellular processes, such as protein degradation, DNA metabolism, and cell differentiation. Substrate proteins can be tagged by distinct types of polymeric ubiquitin (Ub) chains, which determine the eventual fate of the modified protein. A facile, click chemistry based approach for the efficient generation of linkage-defined Ub chains, including Ub dimers, was recently established. Within these chains, individual Ub moieties are connected through a triazole linkage, rather than the natural isopeptide bond. Herein, it is reported that the conformation of an artificially K48-linked Ub dimer resembles that of the natively linked dimer, with respect to structural and dynamic characteristics, as demonstrated by means of high-resolution NMR spectroscopy. Thus, it is proposed that artificially linked Ub dimers, as generated by this approach, represent potent tools for studying the inherently different properties and functions of distinct Ub chains.

At-line multi-angle light scattering detector for faster process development in enveloped virus-like particle purification.

At-line static light scattering and fluorescence monitoring allows direct in-process tracking of fluorescent virus-like particles. We have demonstrated this by coupling at-line multi-angle light scattering and fluorescence detectors to the downstream processing of enveloped virus-like particles. Since light scattering intensity is directly proportional to particle concentration, our strategy allowed a swift identification of product containing fractions and rapid process development. Virus-like particles containing the Human Immunodeficiency Virus-1 Gag protein fused to the Green Fluorescence protein were produced in Human Embryonic Kidney 293 cells by transient transfection. A single-column anion-exchange chromatography method was used for direct capture and purification. The majority of host-cell protein impurities passed through the column without binding. Virus-like particles bound to the column were eluted by linear or step salt gradients. Particles recovered in the step gradient purification were characterized by nanoparticle tracking analysis, size exclusion chromatography coupled to multi-angle light scattering and fluorescence detectors and transmission electron microscopy. A total recovery of 66% for the fluorescent particles was obtained with a 50% yield in the main product peak. Virus-like particles were concentrated 17-fold to final a concentration of 4.45 × 1010 particles/mL. Simple buffers and operation make this process suitable for large scale purposes.

Prophylactic intra-aortic balloon counterpulsation before surgical myocardial revascularization in patients with acute myocardial infarction.

INTRODUCTION: Prophylactic intra-aortic balloon counterpulsation (pIABC) is recommended for high-risk patients undergoing coronary artery bypass grafting (CABG) surgery. Criteria for high-risk patients benefiting from pIABC are unclear. This study aimed to specifically describe the effect of pIABC on outcomes of patients with acute myocardial infarction (AMI) undergoing CABG. METHODS: In 178 of 484 AMI patients (non-ST-segment elevation myocardial infarction [NSTEMI] or ST-segment elevation myocardial infarction [STEMI] ≤5 days before surgery) without cardiogenic shock who underwent CABG between 2008 and 2013, pIABC was initiated preoperatively. After propensity score matching, the outcomes of 400 patients were analyzed (pIABC: 150; Control: 250). RESULTS: After propensity score matching, baseline and operative characteristics were balanced between the groups except for a higher rate of patients with a left ventricular ejection fraction (LVEF)≤30% in the pIABC group (26% vs. Control: 13%; p=0.032). Seven point two percent (7.2%) of the control patients received an IABP intraoperatively or postoperatively. Postoperative extracorporeal life support (ECLS) was only needed in the control group (1.2% vs. 0%; p=0.01). Postoperative plasma curves of troponin I, creatine kinase (CK) and creatine kinase isoform MB (CK-MB) levels were reduced in the pIABC group compared with the control group. In-hospital mortality was reduced in the pIABC group (3.3% vs. control: 6.4%; p=0.18). After multivariate adjustment for other preoperative risk factors, pIABC was significantly protective concerning in-hospital mortality (HR 0.56; 95%-CI 0.023-0.74; p=0.021). Mortality (pIABC vs. control) was more affected in patients with preoperative LVEF≤30% (2/36 (5.6%) vs. 6/31 (19%); heart rate (HR) 0.25; 95%-CI 0.046-1.3; p=0.13) compared with LVEF>30% (3/114 (2.6%) vs. 10/219 (4.6%); HR 0.56; 95%-CI 0.15-2.1; p=0.55). Long-term survival did not differ between the groups. CONCLUSIONS: pIABC in CABG for AMI is associated with reduced perioperative cardiac injury and in-hospital mortality. Long-term survival is not affected.

Photoactivatable Mussel-Based Underwater Adhesive Proteins by an Expanded Genetic Code.

Marine mussels exhibit potent underwater adhesion abilities under hostile conditions by employing 3,4-dihydroxyphenylalanine (DOPA)-rich mussel adhesive proteins (MAPs). However, their recombinant production is a major biotechnological challenge. Herein, a novel strategy based on genetic code expansion has been developed by engineering efficient aminoacyl-transfer RNA synthetases (aaRSs) for the photocaged noncanonical amino acid ortho-nitrobenzyl DOPA (ONB-DOPA). The engineered ONB-DOPARS enables in vivo production of MAP type 5 site-specifically equipped with multiple instances of ONB-DOPA to yield photocaged, spatiotemporally controlled underwater adhesives. Upon exposure to UV light, these proteins feature elevated wet adhesion properties. This concept offers new perspectives for the production of recombinant bioadhesives.