Visual Abstract

Visual Abstract

Visual Abstract

The Internet is full of cats—and in this case, malware-delivering fake cat websites used for very targeted search engine optimization.

Last month, Sophos X-Ops reported several MDR cases where threat actors exploited a vulnerability in Veeam backup servers. We continue to track the activities of this threat cluster, which recently included deployment of a new ransomware. The vulnerability, CVE-2024-40711, was used as part of a threat activity cluster we named STAC 5881. Attacks leveraged compromised […]

Yi Liu
Dec 1, 2020; 19:1968-1985
Research

Litong Nie
Dec 1, 2020; 19:2015-2029
Research

Peter Lasch
Dec 1, 2020; 19:2125-2138
Technological Innovation and Resources

Ryan J Lumpkin
Dec 2, 2020; 0:RA120.002414v1-mcp.RA120.002414
Research

Adult progenitor cell populations typically exist in a quiescent state within a controlled niche environment. However, various stresses or forms of damage can disrupt this state, which often leads to dysfunction and aging. We built a glucocorticoid (GC)-induced liver damage model of mice, found that GC stress induced liver damage, leading to consequences for progenitor cells expansion. However, the mechanisms by which niche factors cause progenitor cells proliferation are largely unknown. We demonstrate that, within the liver progenitor cells niche, Galectin-3 (Gal-3) is responsible for driving a subset of progenitor cells to break quiescence. We show that GC stress causes aging of the niche, which induces the up-regulation of Gal-3. The increased Gal-3 population increasingly interacts with the progenitor cell marker CD133, which triggers focal adhesion kinase (FAK)/AMP-activated kinase (AMPK) signaling. This results in the loss of quiescence and leads to the eventual stemness exhaustion of progenitor cells. Conversely, blocking Gal-3 with the inhibitor TD139 prevents the loss of stemness and improves liver function. These experiments identify a stress-dependent change in progenitor cell niche that directly influence liver progenitor cell quiescence and function.

Protein biosynthesis is fundamental to cellular life and requires the efficient functioning of the translational machinery. At the center of this machinery is the ribosome, a ribonucleoprotein complex that depends heavily on Mg2+ for structure. Recent work has indicated that other metal cations can substitute for Mg2+, raising questions about the role different metals may play in the maintenance of the ribosome under oxidative stress conditions. Here, we assess ribosomal integrity following oxidative stress both in vitro and in cells to elucidate details of the interactions between Fe2+ and the ribosome and identify Mn2+ as a factor capable of attenuating oxidant-induced Fe2+-mediated degradation of rRNA. We report that Fe2+ promotes degradation of all rRNA species of the yeast ribosome and that it is bound directly to RNA molecules. Furthermore, we demonstrate that Mn2+ competes with Fe2+ for rRNA-binding sites and that protection of ribosomes from Fe2+-mediated rRNA hydrolysis correlates with the restoration of cell viability. Our data, therefore, suggest a relationship between these two transition metals in controlling ribosome stability under oxidative stress.

Kinases are critical components of intracellular signaling pathways and have been extensively investigated with regard to their roles in cancer. p21-activated kinase-1 (PAK1) is a serine/threonine kinase that has been previously implicated in numerous biological processes, such as cell migration, cell cycle progression, cell motility, invasion, and angiogenesis, in glioma and other cancers. However, the signaling network linked to PAK1 is not fully defined. We previously reported a large-scale yeast genetic interaction screen using toxicity as a readout to identify candidate PAK1 genetic interactions. En masse transformation of the PAK1 gene into 4,653 homozygous diploid Saccharomyces cerevisiae yeast deletion mutants identified ∼400 candidates that suppressed yeast toxicity. Here we selected 19 candidate PAK1 genetic interactions that had human orthologs and were expressed in glioma for further examination in mammalian cells, brain slice cultures, and orthotopic glioma models. RNAi and pharmacological inhibition of potential PAK1 interactors confirmed that DPP4, KIF11, mTOR, PKM2, SGPP1, TTK, and YWHAE regulate PAK1-induced cell migration and revealed the importance of genes related to the mitotic spindle, proteolysis, autophagy, and metabolism in PAK1-mediated glioma cell migration, drug resistance, and proliferation. AKT1 was further identified as a downstream mediator of the PAK1-TTK genetic interaction. Taken together, these data provide a global view of PAK1-mediated signal transduction pathways and point to potential new drug targets for glioma therapy.

Protein quality control is maintained by a number of integrated cellular pathways that monitor the folding and functionality of the cellular proteome. Defects in these pathways lead to the accumulation of misfolded or faulty proteins that may become insoluble and aggregate over time. Protein aggregates significantly contribute to the development of a number of human diseases such as amyotrophic lateral sclerosis, Huntington's disease, and Alzheimer's disease. In vitro, imaging-based, cellular studies have defined key biomolecular components that recognize and clear aggregates; however, no unifying method is available to quantify cellular aggregates, limiting our ability to reproducibly and accurately quantify these structures. Here we describe an ImageJ macro called AggreCount to identify and measure protein aggregates in cells. AggreCount is designed to be intuitive, easy to use, and customizable for different types of aggregates observed in cells. Minimal experience in coding is required to utilize the script. Based on a user-defined image, AggreCount will report a number of metrics: (i) total number of cellular aggregates, (ii) percentage of cells with aggregates, (iii) aggregates per cell, (iv) area of aggregates, and (v) localization of aggregates (cytosol, perinuclear, or nuclear). A data table of aggregate information on a per cell basis, as well as a summary table, is provided for further data analysis. We demonstrate the versatility of AggreCount by analyzing a number of different cellular aggregates including aggresomes, stress granules, and inclusion bodies caused by huntingtin polyglutamine expansion.

Type I and III interferons induce expression of the “myxovirus resistance proteins” MxA in human cells and its ortholog Mx1 in murine cells. Human MxA forms cytoplasmic structures, whereas murine Mx1 forms nuclear bodies. Whereas both HuMxA and MuMx1 are antiviral toward influenza A virus (FLUAV) (an orthomyxovirus), only HuMxA is considered antiviral toward vesicular stomatitis virus (VSV) (a rhabdovirus). We previously reported that the cytoplasmic human GFP-MxA structures were phase-separated membraneless organelles (“biomolecular condensates”). In the present study, we investigated whether nuclear murine Mx1 structures might also represent phase-separated biomolecular condensates. The transient expression of murine GFP-Mx1 in human Huh7 hepatoma, human Mich-2H6 melanoma, and murine NIH 3T3 cells led to the appearance of Mx1 nuclear bodies. These GFP-MuMx1 nuclear bodies were rapidly disassembled by exposing cells to 1,6-hexanediol (5%, w/v), or to hypotonic buffer (40–50 mosm), consistent with properties of membraneless phase-separated condensates. Fluorescence recovery after photobleaching (FRAP) assays revealed that the GFP-MuMx1 nuclear bodies upon photobleaching showed a slow partial recovery (mobile fraction: ∼18%) suggestive of a gel-like consistency. Surprisingly, expression of GFP-MuMx1 in Huh7 cells also led to the appearance of GFP-MuMx1 in 20–30% of transfected cells in a novel cytoplasmic giantin-based intermediate filament meshwork and in cytoplasmic bodies. Remarkably, Huh7 cells with cytoplasmic murine GFP-MuMx1 filaments, but not those with only nuclear bodies, showed antiviral activity toward VSV. Thus, GFP-MuMx1 nuclear bodies comprised phase-separated condensates. Unexpectedly, GFP-MuMx1 in Huh7 cells also associated with cytoplasmic giantin-based intermediate filaments, and such cells showed antiviral activity toward VSV.

The HIV-1 protein Gag assembles at the plasma membrane and drives virion budding, assisted by the cellular endosomal complex required for transport (ESCRT) proteins. Two ESCRT proteins, TSG101 and ALIX, bind to the Gag C-terminal p6 peptide. TSG101 binding is important for efficient HIV-1 release, but how ESCRTs contribute to the budding process and how their activity is coordinated with Gag assembly is poorly understood. Yeast, allowing genetic manipulation that is not easily available in human cells, has been used to characterize the cellular ESCRT function. Previous work reported Gag budding from yeast spheroplasts, but Gag release was ESCRT-independent. We developed a yeast model for ESCRT-dependent Gag release. We combined yeast genetics and Gag mutational analysis with Gag-ESCRT binding studies and the characterization of Gag-plasma membrane binding and Gag release. With our system, we identified a previously unknown interaction between ESCRT proteins and the Gag N-terminal protein region. Mutations in the Gag-plasma membrane–binding matrix domain that reduced Gag-ESCRT binding increased Gag-plasma membrane binding and Gag release. ESCRT knockout mutants showed that the release enhancement was an ESCRT-dependent effect. Similarly, matrix mutation enhanced Gag release from human HEK293 cells. Release enhancement partly depended on ALIX binding to p6, although binding site mutation did not impair WT Gag release. Accordingly, the relative affinity for matrix compared with p6 in GST-pulldown experiments was higher for ALIX than for TSG101. We suggest that a transient matrix-ESCRT interaction is replaced when Gag binds to the plasma membrane. This step may activate ESCRT proteins and thereby coordinate ESCRT function with virion assembly.

Frank C. Nichols
Dec 1, 2020; 61:1645-1657
Research Articles

Elisa Vidal
Dec 1, 2020; 61:1733-1746
Research Articles

Douglas A. Andres
Dec 1, 2020; 61:1537-1537
Images in Lipid Research

In SAS Merchandise Financial Planning, custom time frame-based data versions do not aggregate correctly when referenced in worksheets with standard hierarchy levels. The data does not aggregate correctly from l

Functions of the gut microbiome have a growing number of implications for host metabolic health, with diet being one of the most significant influences on microbiome composition. Compelling links between diet and the gut microbiome suggest key roles for various macronutrients, including lipids, yet how individual classes of dietary lipids interact with the microbiome remains largely unknown. Sphingolipids are bioactive components of most foods and are also produced by prominent gut microbes. This makes sphingolipids intriguing candidates for shaping diet–microbiome interactions. Here, we used a click chemistry–based approach to track the incorporation of bioorthogonal dietary omega-alkynyl sphinganine (sphinganine alkyne [SAA]) into the murine gut microbial community (Bioorthogonal labeling). We identified microbial and SAA-specific metabolic products through fluorescence-based sorting of SAA-containing microbes (Sort), 16S rRNA gene sequencing to identify the sphingolipid-interacting microbes (Seq), and comparative metabolomics to identify products of SAA assimilation by the microbiome (Spec). Together, this approach, termed Bioorthogonal labeling-Sort-Seq-Spec (BOSSS), revealed that SAA assimilation is nearly exclusively performed by gut Bacteroides, indicating that sphingolipid-producing bacteria play a major role in processing dietary sphinganine. Comparative metabolomics of cecal microbiota from SAA-treated mice revealed conversion of SAA to a suite of dihydroceramides, consistent with metabolic activities of Bacteroides and Bifidobacterium. Additionally, other sphingolipid-interacting microbes were identified with a focus on an uncharacterized ability of Bacteroides and Bifidobacterium to metabolize dietary sphingolipids. We conclude that BOSSS provides a platform to study the flux of virtually any alkyne-labeled metabolite in diet–microbiome interactions.

Roux-en-Y gastric bypass (RYGB) is one of the most commonly performed weight-loss procedures, but how severe obesity and RYGB affects circulating HDL-associated microRNAs (miRNAs) remains unclear. Here, we aim to investigate how HDL-associated miRNAs are regulated in severe obesity and how weight loss after RYGB surgery affects HDL-miRNAs. Plasma HDL were isolated from patients with severe obesity (n=53) before, 6 and 12 months after RYGB by immunoprecipitation using goat anti-human apoA-I microbeads. HDL were also isolated from 18 healthy participants. miRNAs were extracted from isolated HDL and levels of miR-24, miR-126, miR-222 and miR-223 were determined by TaqMan miRNA assays. We found that HDL-associated miR-126, miR-222 and miR-223 levels, but not miR-24 levels, were significantly higher in patients with severe obesity when compared with healthy controls. There were significant increases in HDL-associated miR-24, miR-222 and miR-223 at 12 months after RYGB. Additionally, cholesterol efflux capacity and paraoxonase (PON1) activity were increased and intracellular adhesion molecule-1 (ICAM-1) levels decreased. The increases in HDL-associated miR-24 and miR-223 were positively correlated with increase in cholesterol efflux capacity (r=0.326, P=0.027 and r=0.349, P=0.017 respectively). An inverse correlation was observed between HDL-associated miR-223 and ICAM-1 at baseline. Together, these findings show that HDL-associated miRNAs are differentially regulated in healthy versus patients with severe obesity and are altered after RYGB. These findings provide insights into how miRNAs are regulated in obesity before and after weight reduction, and may lead to the development of novel treatment strategies for obesity and related metabolic disorders.

Lipoprotein (a) [Lp(a)] is a well-known risk factor for cardiovascular disease, but analysis on Lp(a) and renal dysfunction is scarce. We aimed to investigate prospectively the association of serum Lp(a) with the risk of reduced renal function, and further investigated whether diabetic or hypertensive status modified such association. Six thousand two hundred and fifty-seven Chinese adults aged ≤40 years and free of reduced renal function at baseline were included in the study. Reduced renal function was defined as estimated glomerular filtration rate <60 ml/min/1.73 m². During a mean follow-up of 4.4 years, 158 participants developed reduced renal function. Each one-unit increase in log₁₀-Lp(a) (milligrams per deciliter) was associated with a 1.99-fold (95% CI 1.15–3.43) increased risk of incident reduced renal function; the multivariable-adjusted odds ratio (OR) for the highest tertile of Lp(a) was 1.61 (95% CI 1.03–2.52) compared with the lowest tertile (P for trend = 0.03). The stratified analysis showed the association of serum Lp(a) and incident reduced renal function was more prominent in participants with prevalent diabetes [OR 4.04, 95% CI (1.42–11.54)] or hypertension [OR 2.18, 95% CI (1.22–3.89)]. A stronger association was observed in the group with diabetes and high Lp(a) (>25 mg/dl), indicating a combined effect of diabetes and high Lp(a) on the reduced renal function risk. An elevated Lp(a) level was independently associated with risk of incident reduced renal function, especially in diabetic or hypertensive patients.

Spatial changes of FAs in the retina in response to different dietary n-3 formulations have never been explored, although a diet rich in EPA and DHA is recommended to protect the retina against the effects of aging. In this study, Wistar rats were fed for 8 weeks with balanced diet including either EPA-containing phospholipids (PLs), EPA-containing TGs, DHA-containing PLs, or DHA-containing TGs. Qualitative changes in FA composition of plasma, erythrocytes, and retina were evaluated by gas chromatography-flame ionization detector. Following the different dietary intakes, changes to the quantity and spatial organization of PC and PE species in retina were determined by LC coupled to MS/MS and MALDI coupled to MS imaging. The omega-3 content in the lipids of plasma and erythrocytes suggests that PLs as well as TGs are good omega-3 carriers for retina. However, a significant increase in DHA content in retina was observed, especially molecular species as di-DHA-containing PC and PE, as well as an increase in very long chain PUFAs (more than 28 carbons) following PL-EPA and TG-DHA diets only. All supplemented diets triggered spatial organization changes of DHA in the photoreceptor layer around the optic nerve. Taken together, these findings suggest that dietary omega-3 supplementation can modify the content of FAs in the rat retina.

Porphyromonas gingivalis is a Gram-negative anaerobic periodontal microorganism strongly associated with tissue-destructive processes in human periodontitis. Following oral infection with P. gingivalis, the periodontal bone loss in mice is reported to require the engagement of Toll-like receptor 2 (TLR2). Serine-glycine lipodipeptide or glycine aminolipid classes of P. gingivalis engage human and mouse TLR2, but a novel lipid class reported here is considerably more potent in engaging TLR2 and the heterodimer receptor TLR2/TLR6. The novel lipid class, termed Lipid 1256, consists of a diacylated phosphoglycerol moiety linked to a serine-glycine lipodipeptide previously termed Lipid 654. Lipid 1256 is approximately 50-fold more potent in engaging TLR2 than the previously reported serine-glycine lipid classes. Lipid 1256 also stimulates cytokine secretory responses from peripheral blood monocytes and is recovered in selected oral and intestinal Bacteroidetes organisms. Therefore, these findings suggest that Lipid 1256 may be a microbial TLR2 ligand relevant to chronic periodontitis in humans.

The organic anion transporters (OATs) and organic anion–transporting polypeptides (OATPs) belong to the solute carrier (SLC) transporter superfamily and play important roles in handling various endogenous and exogenous compounds of anionic charge. The OATs and OATPs are often implicated in drug therapy by impacting the pharmacokinetics of clinically important drugs and, thereby, drug exposure in the target organs or cells. Various mechanisms (e.g. genetic, environmental, and disease-related factors, drug-drug interactions, and food-drug interactions) can lead to variations in the expression and activity of the anion drug-transporting proteins of OATs and OATPs, possibly impacting the therapeutic outcomes. Previous investigations mainly focused on the regulation at the transcriptional level and drug-drug interactions as competing substrates or inhibitors. Recently, evidence has accumulated that cellular trafficking, post-translational modification, and degradation mechanisms serve as another important layer for the mechanisms underlying the variations in the OATs and OATPs. This review will provide a brief overview of the major OATs and OATPs implicated in drug therapy and summarize recent progress in our understanding of the post-translational modifications, in particular ubiquitination and degradation pathways of the individual OATs and OATPs implicated in drug therapy.

Communication between individuals via molecules, termed chemosignaling, is widespread among animal and plant species. However, we lack knowledge on the specific functions of the substances involved for most systems. The femoral gland is an organ that secretes a waxy substance involved in chemical communication in lizards. Although the lipids and volatile substances secreted by the femoral glands have been investigated in several biochemical studies, the protein composition and functions of secretions remain completely unknown. Applying a proteomic approach, we provide the first attempt to comprehensively characterize the protein composition of femoral gland secretions from the Galápagos marine iguana. Using samples from several organs, the marine iguana proteome was assembled by next-generation sequencing and MS, resulting in 7513 proteins. Of these, 4305 proteins were present in the femoral gland, including keratins, small serum proteins, and fatty acid-binding proteins. Surprisingly, no proteins with discernible roles in partner recognition or inter-species communication could be identified. However, we did find several proteins with direct associations to the innate immune system, including lysozyme C, antileukoproteinase (ALP), pulmonary surfactant protein (SFTPD), and galectin (LGALS1) suggesting that the femoral glands function as an important barrier to infection. Furthermore, we report several novel anti-microbial peptides from the femoral glands that show similar action against Escherichia coli and Bacillus subtilis such as oncocin, a peptide known for its effectiveness against Gram-negative pathogens. This proteomics data set is a valuable resource for future functional protein analysis and demonstrates that femoral gland secretions also perform functions of the innate immune system.

Over the past decade, modern methods of MS (MS) have emerged that allow reliable, fast and cost-effective identification of pathogenic microorganisms. Although MALDI-TOF MS has already revolutionized the way microorganisms are identified, recent years have witnessed also substantial progress in the development of liquid chromatography (LC)-MS based proteomics for microbiological applications. For example, LC-tandem MS (LC-MS²) has been proposed for microbial characterization by means of multiple discriminative peptides that enable identification at the species, or sometimes at the strain level. However, such investigations can be laborious and time-consuming, especially if the experimental LC-MS² data are tested against sequence databases covering a broad panel of different microbiological taxa. In this proof of concept study, we present an alternative bottom-up proteomics method for microbial identification. The proposed approach involves efficient extraction of proteins from cultivated microbial cells, digestion by trypsin and LC–MS measurements. Peptide masses are then extracted from MS¹ data and systematically tested against an in silico library of all possible peptide mass data compiled in-house. The library has been computed from the UniProt Knowledgebase covering Swiss-Prot and TrEMBL databases and comprises more than 12,000 strain-specific in silico profiles, each containing tens of thousands of peptide mass entries. Identification analysis involves computation of score values derived from correlation coefficients between experimental and strain-specific in silico peptide mass profiles and compilation of score ranking lists. The taxonomic positions of the microbial samples are then determined by using the best-matching database entries. The suggested method is computationally efficient – less than 2 mins per sample - and has been successfully tested by a test set of 39 LC-MS¹ peak lists obtained from 19 different microbial pathogens. The proposed method is rapid, simple and automatable and we foresee wide application potential for future microbiological applications.

Specific E3 ligases target tumor suppressors for degradation. Inhibition of such E3 ligases may be an important approach to cancer treatment. RNF146 is a RING domain and PARylation-dependent E3 ligase that functions as an activator of the β-catenin/Wnt and YAP/Hippo pathways by targeting the degradation of several tumor suppressors. Tankyrases 1 and 2 (TNKS1/2) are the only known poly-ADP-ribosyltransferases that require RNF146 to degrade their substrates. However, systematic identification of RNF146 substrates have not yet been performed. To uncover substrates of RNF146 that are targeted for degradation, we generated RNF146 knockout cells and TNKS1/2-double knockout cells and performed proteome profiling with label-free quantification as well as transcriptome analysis. We identified 160 potential substrates of RNF146, which included many known substrates of RNF146 and TNKS1/2 and 122 potential TNKS-independent substrates of RNF146. In addition, we validated OTU domain-containing protein 5 and Protein mono-ADP-ribosyltransferase PARP10 as TNKS1/2-independent substrates of RNF146 and SARDH as a novel substrate of TNKS1/2 and RNF146. Our study is the first proteome-wide analysis of potential RNF146 substrates. Together, these findings not only demonstrate that proteome profiling can be a useful general approach for the systemic identification of substrates of E3 ligases but also reveal new substrates of RNF146, which provides a resource for further functional studies.

Mallory-Denk-bodies (MDBs) are hepatic protein aggregates associated with inflammation both clinically and in MDB-inducing models. Similar protein aggregation in neurodegenerative diseases also triggers inflammation and NF-B activation. However, the precise mechanism that links protein aggregation to NF-B-activation and inflammatory response remains unclear. Herein we find that treating primary hepatocytes with MDB-inducing agents (N-methylprotoporphyrin (NMPP), protoporphyrin IX (PPIX), or Zinc-protoporphyrin IX (ZnPP)) elicited an IBα-loss with consequent NF-B activation. Four known mechanisms of IBα-loss i.e. the canonical ubiquitin-dependent proteasomal degradation (UPD), autophagic-lysosomal degradation, calpain degradation and translational inhibition, were all probed and excluded. Immunofluorescence analyses of ZnPP-treated cells coupled with 8 M urea/CHAPS-extraction revealed that this IBα-loss was due to its sequestration along with IBβ into insoluble aggregates, thereby releasing NF-B. Through affinity pulldown, proximity biotinylation by antibody recognition, and other proteomic analyses, we verified that NF-B subunit p65, which stably interacts with IBα under normal conditions, no longer binds to it upon ZnPP-treatment. Additionally, we identified 10 proteins that interact with IBα under baseline conditions, aggregate upon ZnPP-treatment, and maintain the interaction with IBα after ZnPP-treatment, either by cosequestering into insoluble aggregates or through a different mechanism. Of these 10 proteins, the nucleoporins Nup153 and Nup358/RanBP2 were identified through RNA-interference, as mediators of IBα-nuclear import. The concurrent aggregation of IBα, NUP153, and RanBP2 upon ZnPP-treatment, synergistically precluded the nuclear entry of IBα and its consequent binding and termination of NF-B activation. This novel mechanism may account for the protein aggregate-induced inflammation observed in liver diseases, thus identifying novel targets for therapeutic intervention. Because of inherent commonalities this MDB cell model is a bona fide protoporphyric model, making these findings equally relevant to the liver inflammation associated with clinical protoporphyria.

Les troubles gastro-intestinaux peuvent avoir un impact significatif sur la qualité de vie des patients. Ils engendrent en effet des symptômes variés et inconfortables allant de douleurs abdominales et nausées à des troubles plus graves comme les maladies inflammatoires chroniques de l’intestin. Quelles sont les principales pathologies rencontrées dans cette spécialité de la médecine ? À quel […]

L’article Quelles sont les principales pathologies en gastroentérologie ? est apparu en premier sur Ortho Doc France.

Many cell surface and secreted proteins are modified by the covalent addition of glycans that play an important role in the development of multicellular organisms. These glycan modifications enable communication between cells and the extracellular matrix via interactions with specific glycan-binding lectins and the regulation of receptor-mediated signaling. Aberrant protein glycosylation has been associated with the development of several muscular diseases suggesting essential glycan- and lectin-mediated functions in myogenesis and muscle development but our molecular understanding of the precise glycans, catalytic enzymes and lectins involved remain only partially understood. Here, we quantified dynamic remodeling of the membrane-associated proteome during a time-course of myogenesis in cell culture. We observed wide-spread changes in the abundance of several important lectins and enzymes facilitating glycan biosynthesis. Glycomics-based quantification of released N-linked glycans confirmed remodeling of the glycome consistent with the regulation of glycosyltransferases and glycosidases responsible for their formation including a previously unknown di-galactose-to-sialic acid switch supporting a functional role of these glycoepitopes in myogenesis. Furthermore, dynamic quantitative glycoproteomic analysis with multiplexed stable isotope labelling and analysis of enriched glycopeptides with multiple fragmentation approaches identified glycoproteins modified by these regulated glycans including several integrins and growth factor receptors. Myogenesis was also associated with the regulation of several lectins most notably the up-regulation of galectin-1 (LGALS1). CRISPR/Cas9-mediated deletion of Lgals1 inhibited differentiation and myotube formation suggesting an early functional role of galectin-1 in the myogenic program. Importantly, similar changes in N-glycosylation and the up-regulation of galectin-1 during postnatal skeletal muscle development were observed in mice. Treatment of new-born mice with recombinant adeno-associated viruses to overexpress galectin-1 in the musculature resulted in enhanced muscle mass. Our data form a valuable resource to further understand the glycobiology of myogenesis and will aid the development of intervention strategies to promote healthy muscle development or regeneration.

Cullin RING E3 Ligases (CRLs) ubiquitylate hundreds of important cellular substrates. Here we have assembled and purified the Ankyrin repeat and SOCS Box protein 9 CUL5 RBX2 Ligase (ASB9-CRL) in vitro and show how it ubiquitylates one of its substrates, CKB. CRLs occasionally collaborate with RING between RING E3 ligases (RBRLs) and indeed, mass spectrometry analysis showed that CKB is specifically ubiquitylated by the ASB9-CRL-ARIH2-UBE2L3 complex. Addition of other E2s such as UBE2R1 or UBE2D2 contribute to polyubiquitylation but do not alter the sites of CKB ubiquitylation. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis revealed that CUL5 neddylation allosterically exposes its ARIH2 binding site, promoting high affinity binding, and it also sequesters the NEDD8 E2 (UBE2F) binding site on RBX2. Once bound, ARIH2 helices near the Ariadne domain active site are exposed, presumably relieving its autoinhibition. These results allow us to propose a model of how neddylation activates ASB-CRLs to ubiquitylate their substrates.

Tackling Illegal Wildlife Trade in Africa: Economic Incentives and Approaches Research paper sysadmin 5 October 2018

Combating illegal wildlife trade and further pursuing conservation-development models could help generate considerable economic benefits for African countries, while ensuring the long-term preservation of Africa’s wealth of natural capital.

Summary

• The illegal wildlife trade (IWT) significantly impacts African economies by destroying and corroding natural, human and social capital stocks. This hinders the achievement of the Sustainable Development Goals (SDGs) and has an impact on national budgets. Illicit financial flows from IWT deny revenue to governments where legal wildlife product trade exists and perpetuate cash externalization. IWT diverts national budgets away from social or development programmes, increases insecurity and threatens vulnerable populations.
• In expanding wildlife economies and pursuing conservation-driven development models, governments can protect their citizens, derive revenue from wildlife products, and establish world class tourism offerings. The illegal exploitation of wildlife is often due to a failure to enforce rights over those resources, where rights are unclearly defined or not fully exercised. Southern African countries have defined these rights in various ways, contributing to regional differences in conservation practices and the socio-economic benefits derived from wildlife resources. Combating IWT is an important step towards allowing legitimate business and communities to develop livelihoods that incentivize stewardship and connect people to conservation.
• The Southern African Development Community (SADC) has several framework policies for the establishment of transfrontier conservation areas (TFCAs). These promote local stewardship across multiple land-use areas to conserve biodiversity and increase the welfare and socioeconomic development of rural communities. Private-sector partnerships also increase skills transfer, improve access to investment finance, and expand economic opportunities, including through the promotion of local procurement. The economic benefits of TFCAs extend beyond tourism.
• The economic value of African ecosystems is often under-recognized because they remain unquantified, partly due to the lack of available data on the broader economic costs of IWT. Improved monitoring and evaluation with key performance indicators would help governments and citizens to appreciate the economic value of combating IWT.

Cooking in Displacement Settings: Engaging the Private Sector in Non-wood-based Fuel Supply Research paper sysadmin 22 January 2019

In displacement settings, providing cooking solutions that reduce negative impacts on the environment and health remains a challenge for local governments, humanitarian agencies, businesses and refugees.

Summary

• Providing adequate cooking fuel and clean-burning, fuel-efficient stoves in displacement settings has long been a major challenge for local authorities, humanitarian agencies, non-governmental organizations, local communities and refugees themselves. Refugees generally have limited access to modern cooking solutions. Most either depend on insufficient humanitarian agency handouts of ‘in-kind’ firewood or have to travel long distances to collect firewood.
• There is significant potential for private-sector engagement in this context – which, though largely overlooked to date, could result in win-win scenarios for all stakeholders. Refugee camps and other displacement settings present opportunities for private-sector cooking fuel companies to expand their customer bases, with the added advantage for vendors of offering concentrated demand and scope for economies of scale.
• For the Kakuma refugee camp complex in Kenya, the Moving Energy Initiative (MEI) decided to engage with the private sector directly. The MEI requested expressions of interest from local private-sector companies for expanding sales and distribution of fuels in the complex through the concession. The winning company – National Oil Corporation of Kenya – is to receive a prize of $50,000 for its proposed concession to supply liquefied petroleum gas both to refugees in the Kakuma complex and to the surrounding host community.
• The MEI also conducted interviews with various stakeholders in other contexts and countries who are engaged in efforts to develop market-based approaches to providing clean, fuel-efficient cooking solutions to refugees.
• Based on the interviews and the concession process, the MEI recommends greater donor investment and longer-term guaranteed funding for cooking interventions. This is needed to allow sufficient time to build sustainable markets and secure the requisite engagement and investments from the private sector.
• Larger, longer-term investments by the private sector – supported through partnerships with donors and humanitarian agencies – in infrastructure and demand creation (both in and outside the refugee community) can reduce the price of alternative solutions and support a gradual transition away from subsidies.

In eukaryotic DNA replication, DNA polymerase ε (Polε) is responsible for leading strand synthesis, whereas DNA polymerases α and δ synthesize the lagging strand. The human Polε (hPolε) holoenzyme is comprised of the catalytic p261 subunit and the noncatalytic p59, p17, and p12 small subunits. So far, the contribution of the noncatalytic subunits to hPolε function is not well understood. Using pre-steady-state kinetic methods, we established a minimal kinetic mechanism for DNA polymerization and editing catalyzed by the hPolε holoenzyme. Compared with the 140-kDa N-terminal catalytic fragment of p261 (p261N), which we kinetically characterized in our earlier studies, the presence of the p261 C-terminal domain (p261C) and the three small subunits increased the DNA binding affinity and the base substitution fidelity. Although the small subunits enhanced correct nucleotide incorporation efficiency, there was a wide range of rate constants when incorporating a correct nucleotide over a single-base mismatch. Surprisingly, the 3'→5' exonuclease activity of the hPolε holoenzyme was significantly slower than that of p261N when editing both matched and mismatched DNA substrates. This suggests that the presence of p261C and the three small subunits regulates the 3'→5' exonuclease activity of the hPolε holoenzyme. Together, the 3'→5' exonuclease activity and the variable mismatch extension activity modulate the overall fidelity of the hPolε holoenzyme by up to 3 orders of magnitude. Thus, the presence of p261C and the three noncatalytic subunits optimizes the dual enzymatic activities of the catalytic p261 subunit and makes the hPolε holoenzyme an efficient and faithful replicative DNA polymerase.

Faithful replication of the mitochondrial genome is carried out by a set of key nuclear-encoded proteins. DNA polymerase γ is a core component of the mtDNA replisome and the only replicative DNA polymerase localized to mitochondria. The asynchronous mechanism of mtDNA replication predicts that the replication machinery encounters dsDNA and unique physical barriers such as structured genes, G-quadruplexes, and other obstacles. In vitro experiments here provide evidence that the polymerase γ heterotrimer is well-adapted to efficiently synthesize DNA, despite the presence of many naturally occurring roadblocks. However, we identified a specific G-quadruplex–forming sequence at the heavy-strand promoter (HSP1) that has the potential to cause significant stalling of mtDNA replication. Furthermore, this structured region of DNA corresponds to the break site for a large (3,895 bp) deletion observed in mitochondrial disease patients. The presence of this deletion in humans correlates with UV exposure, and we have found that efficiency of polymerase γ DNA synthesis is reduced after this quadruplex is exposed to UV in vitro.

Timely repair of DNA double-strand breaks (DSBs) is essential to maintaining genomic integrity and preventing illnesses induced by genetic abnormalities. We previously demonstrated that the E3 ubiquitin ligase SMURF2 plays a critical tumor suppressing role via its interaction with RNF20 (ring finger protein 20) in shaping chromatin landscape and preserving genomic stability. However, the mechanism that mobilizes SMURF2 in response to DNA damage remains unclear. Using biochemical approaches and MS analysis, we show that upon the onset of the DNA-damage response, SMURF2 becomes phosphorylated at Ser384 by ataxia telangiectasia mutated (ATM) serine/threonine kinase, and this phosphorylation is required for its interaction with RNF20. We demonstrate that a SMURF2 mutant with an S384A substitution has reduced capacity to ubiquitinate RNF20 while promoting Smad3 ubiquitination unabatedly. More importantly, mouse embryonic fibroblasts expressing the SMURF2 S384A mutant show a weakened ability to sustain the DSB response compared with those expressing WT SMURF2 following etoposide treatment. These data indicate that SMURF2-mediated RNF20 ubiquitination and degradation controlled by ataxia telangiectasia mutated–induced phosphorylation at Ser384 constitutes a negative feedback loop that regulates DSB repair.

MLB Network's countdown of baseball's best players at each position continued with the third installment of the "Top 10 Right Now!" series, featuring the game's top left and center fielders.

Business Development in Madagascar: How to Enable Entrepreneurialism 15 November 2017 — 12:00PM TO 1:00PM Anonymous (not verified) 9 November 2017 Chatham House, London

Mugabe’s Departure Ushers in a Heady New Era for Zimbabwe Expert comment sysadmin 23 November 2017

The country is experiencing an almost unprecedented convergence, with traditional political, economic and social fault lines bridged as Zimbabweans make common cause for change.

The ecstatic scenes said it all – Zimbabweans around the world are celebrating the resignation of Robert Mugabe as president. In January 1980, hundreds of thousands of Zimbabweans thronged Zimbabwe Grounds stadium in Highfields township, Harare, to welcome Mugabe back from exile. In March 1980, with reggae icon Bob Marley and Britain’s Prince Charles in attendance, thousands filled Rufaro Stadium to witness the handover from Rhodesia to the new nation of Zimbabwe. Thirty-seven years later, the largest crowds Harare has ever witnessed flooded the streets once again; not to welcome Mugabe in, but to see him out. One simple, taut phrase summed up the day’s events: ‘This is our second independence day.’

How did it come to this?

History has been put on fast-forward, and left Zimbabwe – and the world – shaken. Just two weeks ago, it seemed to be the height of folly to think that Mugabe would leave office on any but his own terms. Emmerson Mnangagwa had been sacked as vice president, and his followers had been purged. Grace Mugabe, with ringing endorsements from the women’s and youth leagues, looked set to be elevated to the vice presidency at the ZANU-PF congress in less than a month’s time.

Mugabe was expected to stay until the 2018 elections, after which he would hand over the presidency to his wife. It was the prospect of Grace Mugabe becoming Zimbabwe’s next president which brought in the military. Aware that they had three weeks or less to prevent a dynastic succession and a looming purge of the military itself, Zimbabwe’s military chose, not the audacity of hope, but the hope of audacity, and launched Operation Restore Legacy to stop the rot.

What has happened in Zimbabwe is not a people’s revolution in the traditional sense. The Bourbons in France, the Romanov dynasty in Russia, the Shah of Iran, and the autocrats of north Africa’s Arab Spring were all felled by continuous street protests which ultimately received the support of the military.

In Zimbabwe it has been the military who have been the drivers of revolutionary change. What has happened is that an internal party-factional power struggle has inadvertently led to a military-guided popular revolution and the ousting of the Mugabes. Zimbabwe’s military, often seen as the guardians of the state, became instead the guardians of the people. They are seen, for now at least, as liberators, and national heroes. This has been a very Zimbabwean revolution.

So what next?

These are heady days. Zimbabwe is experiencing an almost unprecedented national convergence, with traditional political, economic and social fault lines bridged as Zimbabweans make common cause for change. It is not quite a ‘Zimbabwe Spring’, but it is perhaps a ‘Zimbabwe Sunrise’.

Parliament, which on Tuesday had met to impeach Robert Mugabe, is now installing, through constitutional procedures, Emmerson Mnangagwa as president, who will be given the mandate to form an interim government. Mnangagwa will be further ratified at the ZANU-PF Congress in December where he will be named and acclaimed as ZANU-PF’s candidate for the next general elections, which constitutionally are due by mid-2018 (although it is unclear whether this will indeed be the case).

Mnangagwa has a full in-tray. He needs to form a government quickly and has to balance the need for inclusivity and consultation, with the undoubted pressure to reward his followers. With Zimbabwe’s economy nearing paralysis, Zimbabwe’s new president will be under pressure to deliver. Although many are nervous about his history as Mugabe’s ally and his reputation for toughness, Mnangagwa is also an astute political survivor, and has been pro-business and supportive of Zimbabwe’s ongoing re-engagement with the global community.

Zimbabwe has become a cashless society not by design, but by default; with formal unemployment at 80 per cent and with a largely informalized economy in which much of Zimbabwe’s citizenry have been reduced to penury and classic short-termism, there is plenty for Zimbabwe’s next president to think about. Activists wonder whether he will try to introduce systemic change, or merely go through the motions. He may well face a binary choice between government or governance.

And yet there are also positives. Zimbabwe’s institutions have proven to be resilient, and there is still a reservoir of dedicated and competent professionals in both public and private sectors. Although still laggardly, Zimbabwe had begun to progress in ‘ease of doing business’ indices. There is a large diaspora who have continued to engage with Zimbabwe; and Zimbabwe’s recent ‘Look East’ and de facto ‘Look West’ re-engagement policies can be built upon.

Many are urging caution and saying that Zimbabwe needs a second, truly democratic revolution. Perhaps. But right now, Mnangagwa should be given a chance. Farai, a friend of mine in Harare, said this: ‘Yes we know this euphoria may be short-lived. But even if it turns out that we were only happy for a day, let’s make it a brilliant day. Rega tifare nhasi (Let us be happy today).’

A version of this article was first published by the Guardian.

Mugabe’s Fall Is a Wake-Up Call for Africa’s Leaders Expert comment sysadmin 27 November 2017

The continent’s long-standing leaders will come under increasing pressure to demonstrate their societal value. Some will become more oppressive; others may conclude that their time has expired.

The end of the Mugabe presidency in Zimbabwe – with the swearing in of Emmerson Mnangagwa in Harare on Friday – is being watched closely across Africa, and especially by its long-standing leaders.

Currently, 30 per cent of African countries are ruled by long-standing rulers, defined as heads of state that have ruled for more than 10 years. Africa is not unique in this respect (Central Asia also has its share of ageing leaders), but Africa has a long tradition, and about a fifth of all African heads of state since independence can be classified as long-standing.

A recent study, African Futures: Horizon 2025, by the European Union Institute of Security Studies (and which this writer contributed to), shows that long-standing rulers in Africa are reducing in number. President José Eduardo dos Santos of Angola stepped down voluntarily in September after almost 38 years in office, and Yahya Jammeh of Gambia was forced out after 23 years in office in early 2017. Robert Mugabe was forced out as leader earlier this week after 37 years.

This still leaves a cluster of other ageing leaders: Teodoro Obiang Nguema Mbasogo of Equatorial Guinea (38 years); Paul Biya of Cameroon (35 years); Yoweri Museveni of Uganda (31 years); Omar al-Bashir of Sudan (28 years); and eight others.

Many of them are coming under increased internal pressure. Demonstrations against Togo’s Faure Gnassingbé in Lome over the summer resulted in him agreeing that any future president could stand for only two terms. In the Democratic Republic of the Congo, Joseph Kabila is also under increased pressure to agree to elections, after 16 years in power.

Within all of this, there is a pattern of leaders in west and southern Africa adopting the principle of only serving two terms.

De-facto monarchies

Long-standing rulers still thrive in central Africa and its Great Lakes region. Presidents here have successfully changed constitutions to remain in office. They include Denis Sassou Nguesso of the Republic of the Congo and Yoweri Museveni of Uganda. Zimbabwe will be a warning to them that they should not assume that they will be able to behave as de-facto monarchies, leaving office only after dying of natural causes and handing power over to their family.

Robert Mugabe’s intention to hand power to his wife, Grace, spectacularly backfired. As a couple of Zimbabwe military officials dryly commented: ‘Leadership is not sexually transmitted.’ Former president Hosni Mubarak in Egypt also miscalculated by trying to groom his son, although Ali Bongo Ondimba succeeded his father as president of Gabon after his father died. Equatorial Guinea is still heading for a crisis as President Obiang is grooming his deeply unpopular playboy son, Teodorin, to succeed him.

What Zimbabwe reminds us is that, with the exception of central Africa, there will be more long-standing leaders in Africa disappearing over the coming decade. This is due partly to pressure and partly to their ageing: 13 current long-standing rulers are aged between 65 and 84 years old. This means there will be more transitions taking place such as the one that occurred in Zimbabwe on Friday or the smooth one in Angola in September, when president dos Santos stepped down and handed power to João Lourenço.

This is good news for Africa, which has the most youthful and fastest-growing population in the world. It is the second-largest and second-most populated continent. More than 40 per cent of Africans are under 15, and 20 per cent are between 15 and 24. By 2050, one third of the world’s youth population will live in Africa, up from one fifth in 2012. This means a dramatic disconnect is developing between long-standing leaders and their population.

Generational politics was visible over the past week in Zimbabwe and in the end the older generation prevailed through military intervention. This is transitional politics, and there is likely to be more of it.

Increasing pressure

Other long-serving leaders like Museveni have watched closely. Museveni has already responded to shore up support of his military by giving them a significant pay rise. There is likely to be more investment in the military by Africa’s long-standing leaders in the coming months.

Change in Africa comes in fits and starts. The fall of Mugabe is a reminder that Africa is dynamic and change is occurring all the time. Africa’s long-standing leaders will come under increasing pressure to demonstrate their societal value. Some will become more oppressive; others may conclude that their time has expired and that they should welcome a transition.

This is the key lesson of Angola – where president dos Santos willingly retired after 37 years in power. Mugabe dreamed of dying in office and being succeeded by his wife – and was forced out by the military. I predict both models will be repeated in Africa in coming years.

This article was originally published in the Irish Times.