article A new article, "Mirrorless cameras" has been added to "Product Technology". By www.nikon.com Published On :: Fri, 17 Jan 2020 13:00:00 +0900 Full Article Technology & Design
article A new article, "The compact mirrorless Z 50 packs mighty technologies" has been added to "Stories". By www.nikon.com Published On :: Fri, 17 Jan 2020 13:00:00 +0900 Full Article Technology & Design
article A new article, "SnapBridge" has been added to "Design". By www.nikon.com Published On :: Thu, 06 Feb 2020 13:00:00 +0900 Full Article Technology & Design
article A new article, "Nano Crystal Coat puts innovation right before your eyes" has been added to "Stories". By www.nikon.com Published On :: Thu, 27 Feb 2020 15:00:00 +0900 Full Article Technology & Design
article Technology & Design:New articles, "Alignment Station" and "Non-Contact Large-Volume Inspection System" have been added to "Product Technology". By www.nikon.com Published On :: Tue, 14 Apr 2020 15:00:00 +0900 Full Article Technology & Design
article Technology & Design:A new article, "Manufacturing glass that grows like a lifeform" has been added to "Stories". By www.nikon.com Published On :: Mon, 20 Apr 2020 15:00:00 +0900 Full Article Technology & Design
article How to Boost Visuals Using Particles in Unreal Engine* By feedproxy.google.com Published On :: 2018-11-05T12:26:00+05:30 Particle parameters are a powerful system built into the Unreal Engine* that allows the customization of particle systems outside of Unreal Engine 4's Cascade particle editor. This tutorial create... Full Article
article 5 articles to read as you embark on data preparation By feedproxy.google.com Published On :: Wed, 22 Jan 2020 15:45:09 +0000 Learn how to get started with self-service data prep in these go-to articles. The post 5 articles to read as you embark on data preparation appeared first on The Data Roundtable. Full Article Uncategorized data management for analytics data preparation
article SemiEngineering Article: Why IP Quality Is So Difficult to Determine By feedproxy.google.com Published On :: Fri, 07 Jun 2019 19:53:00 GMT Differentiating good IP from mediocre or bad IP is getting more difficult, in part because it depends upon how and where it is used and in part, because even the best IP may work better in one system than another—even in chips developed by the same vendor. So, how do you measure IP quality and why it is so complicated? The answer depends on who is asking. Most of the time, the definition of IP quality depends on your vantage point. If you are an R&D manager, IP quality means something. If you are a global supply manager, IP quality means something else. If you are an SoC start-up, your measure of quality is quite different from that of an established fabless company. If you are designing IP in-house, then your considerations are very different than being a commercial IP vendor. If you are designing an automotive SoC, then we are in a totally different category. How about as an IP vendor? How do you articulate IP quality metrics to your customers? This varies greatly by the type of IP, as well. When it comes to interface (hard) IP and controllers, if you are an R&D manager, your goal is to design IP that meets the IP specifications and PPA (power, performance, and area) targets. You need to validate your design via silicon test chips. This applies to all hard PHYs, which must be mapped to a particular foundry process. For controllers that are in RTL form—we called these soft IP—you have to synthesize them into a particular target library in a particular foundry process in order to realize them in a physical form suitable for SoC integration. Of course, your design will need to go through a series of design validation steps via simulation, design verification and passing the necessary DRC checks, etc. In addition, you want to see the test silicon in various process corners to ensure the IP is robust and will perform well under normal process variations in the production wafers. For someone in IP procurement, the measure of quality will be based on the maturity of the IP. This involves the number of designs that have been taped out using this IP and the history of bug reports and subsequent fixes. You will be looking for quality of the documentation and the technical deliverables. You will also benchmark the supplier’s standard operating procedures for bug reporting and technical support, as well as meeting delivery performance in prior programs. This is in addition to the technical teams doing their technical diligence. An in-house team that is likely to design IP for a particular SoC project will be using an established design flow and will have legacy knowledge of last generation’s IP. They may be required to design the IP with some reusability in mind for future programs. However, such reusability requirements will not need to be as stringent and as broad as those of commercial IP vendors because there are likely to be established metrics and procedures in place to follow as part of the design team’s standard operating procedures. Many times, new development based on a prior design that has been proven in use will be started, given this stable starting point. All of these criteria help the team achieve a quality outcome more easily. Then, if designing for an automotive SoC, additional heavy lifting is required. Aside from ensuring that the IP meets the specifications of the protocol standards and passes the compliance testing, you also must pay attention to meeting functional safety requirements. This means adherence to ISO 26262 requirements and subsequently achieving ASIL certification. Oftentimes, even for IP, you must perform some AEC-Q100-related tests that are relevant to IP, such as ESD, LU, and HTOL. To read more, please visit: https://semiengineering.com/why-ip-quality-is-so-difficult-to-determine/ Full Article IP cadence IP blocks Automotive Ethernet ip cores Tensilica semiconductor IP Design IP and Verification IP
article Apache2 Web Server Hardening Article By packetstormsecurity.com Published On :: Mon, 10 Feb 2020 15:20:36 GMT This is an article discussing Apache2 Web Server hardening. Written in Turkish. Full Article
article Energy Storage and Biofuels Top RenewableEnergyWorld.com’s Most Commented Articles of 2014 By feedproxy.google.com Published On :: 2014-12-29T16:45:00Z The online community of readers who visit RenewableEnergyWorld.com is an important aspect of the news and information that we offer renewable energy stakeholders. We often post news that we feel will get people to view important topics from new angles, offering insights and opinions about technology, policy and more. Often that leads to engaging and informative discussions that add even more value to the article that we have posted. Full Article Energy Efficiency Hydropower Baseload Storage Energy Efficiency Bioenergy Policy Wind Power Solar Geothermal
article RenewableEnergyWorld.com's Most-read Articles of 2014 By feedproxy.google.com Published On :: 2014-12-30T13:00:00Z At the close of each year, we like to take a look back to see which stories made an impact on our readers. This year's most read articles show the many twists and turns that the industry took this year and reveal interesting trends for us as editors and for other industry insiders. Full Article Energy Efficiency Hydropower Baseload Storage Energy Efficiency Bioenergy Wind Power Solar Geothermal
article EU Allows China to Edit Op-Ed Article, Removing Mention of Virus Origins By www.rfa.org Published On :: 2020-05-08T18:50:01Z The EU's ambassador made a 'mistake' in giving the go-ahead for the censorship, officials say. Full Article Story
article Article: Pre-ticked boxes arent consent for cookie placement By www.eversheds.com Published On :: 2019-10-11 CJEU Ruling on Cookies On 1 October 2019, the Court of Justice of the European Union (CJEU) gave a preliminary ruling1 on questions referred from the Bundesgerichtshof (Federal Court of Justice in Germany) that: Consent is not validly ... Full Article
article Strange particles found in Antarctica cannot be explained by physics By www.newscientist.com Published On :: Tue, 14 Jan 2020 10:40:59 +0000 A NASA science balloon picked up two high-energy particles and a new analysis reveals that they can't be explained by the standard model of particle physics Full Article
article First-Ever Journal Article Tag Suite Conference (JATS-Con) to be Held in November 2010 By www.ncbi.nlm.nih.gov Published On :: Thu, 17 Jun 2010 08:00:00 EST PMC is pleased to announce the first of what we hope will be an annual series of conferences for users of the Journal Article Tag Suite, that is, for users of any of the “NLM DTDs”. The Journal Article Tag Suite Conference (JATS-Con) is a peer-reviewed conference that will feature a broad range of content on the Tag Suite—from the technical components to publishing theory—as well as the latest news on the Tag Suite. The conference will be hosted by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine on the NIH campus in Bethesda, Maryland on November 1 & 2, 2010. For more information on the conference, see https://jats.nlm.nih.gov/jats-con. Note: There is no charge for the conference; however, space is limited so preregistration is required. Full Article
article Search for Open Access Articles by License By www.ncbi.nlm.nih.gov Published On :: Mon, 5 Aug 2013 08:00:00 EST You can now search for Open Access articles that have certain types of licenses, by using special filters in both PMC and PubMed. These filters are based on license information that is provided to PMC by publishers and other content providers, as encoded by machine-readable identifiers in the source XML of each article. For more information, see our updated Open Access Subset page. Full Article
article Three Million Articles are Now in PMC!! By www.ncbi.nlm.nih.gov Published On :: Mon, 24 Feb 2014 08:00:00 EST As of February 21, 2014, PMC became home to three million articles! As listed on our home page, the content has been provided in part by 1441 full participation journals, 277 NIH Portfolio journals and 2470 selective deposit journals. For related information on PMC milestones, see these announcements from 2007 and 2010, respectively. Full Article
article Full text now available for OA subset articles, in plain text format By www.ncbi.nlm.nih.gov Published On :: Thu, 5 Feb 2015 08:00:00 EST In order to facilitate text and data mining for articles in the Open Access Subset, we are now providing plain text files for those articles on our FTP site. These files contain the full text of the article, extracted either from the XML source files, or (for those articles that don't have XML) the PDF files. Users are directly and solely responsible for compliance with copyright restrictions and are expected to adhere to the terms and conditions defined by the copyright holder (see the PMC Copyright Notice).These text files are bundled in gzipped archives. Note that these files are quite large (each greater than one gigabyte). They are available for download as: ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/articles.txt.0-9A-B.tar.gz ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/articles.txt.C-H.tar.gz ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/articles.txt.I-N.tar.gz ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/articles.txt.O-Z.tar.gz These files are updated every week, on Saturday.For more information, see the Bulk Packages of OA Articles section of our FTP Service page. Full Article
article Article Display Updates By www.ncbi.nlm.nih.gov Published On :: Wed, 28 Mar 2018 08:00:00 EST In collaboration with Europe PMC, PMC has rolled out several updates to our article display in order to enhance the transparency and readability of the content.Navigating from the PMC record to the PubMed record has been made easier by the addition of hyperlinked PubMed IDs (PMIDs) in the upper right-hand corner of article records. Clicking the PMID link will take you to the corresponding citation record in PubMed.The PMC Disclaimer link has also been moved out of the Copyright and License information section for easier discovery and access. This page describes what content is included in PMC as well as other important NCBI and NLM disclaimer information.Additionally, two changes have been implemented to improve the functionality of author names. Users can now click on an author name to view the author’s affiliation(s). Users also have the option of running a quick author name search in PMC by clicking the linked author name in “Find articles by [author name]”. In the example pictured above, the search would be for “Sawyer SL”[Author].And finally, figures and tables have been moved inline in the article display. By moving away from the thumbnail display, PMC hopes to make it easier for users to view figure and table data as they read articles. Users may still click on the figure/table title or “Open in separate window” (as available) link for a closer look. We hope these updates improve the overall user experience in PMC and look forward to hearing your feedback. ReferencesScreenshots from:Qiao, Y., Yang, J., Liu, L., Zeng, Y., Ma, J., Jia, J., … Wang, Y. (2018). Successful treatment with pazopanib plus PD-1 inhibitor and RAK cells for advanced primary hepatic angiosarcoma: a case report. BMC Cancer, 18, 212. http://doi.org/10.1186/s12885-018-3996-3Stabell, A. C., Meyerson, N. R., Gullberg, R. C., Gilchrist, A. R., Webb, K. J., Old, W. M., … Sawyer, S. L. (2018). Dengue viruses cleave STING in humans but not in nonhuman primates, their presumed natural reservoir. eLife, 7, e31919. http://doi.org/10.7554/eLife.31919Both articles made available under a CC-BY license. Full Article
article Selected Articles from This Issue By mct.aacrjournals.org Published On :: 2020-05-04T05:39:42-07:00 Full Article
article Top-Cited Articles from Dental Education Journals, 2009 to 2018: A Bibliometric Analysis By www.jdentaled.org Published On :: 2019-12-01T06:00:18-08:00 The number of citations an article receives is an important indicator to quantify its influence in its field. The aim of this study was to identify and analyze the characteristics of the 50 top-cited articles addressing dental education published in two journals dedicated to dental education (European Journal of Dental Education and Journal of Dental Education). The Web of Science database was searched to retrieve the 50 most-cited articles from the two journals in December 2018. The top-cited articles were analyzed for journal of publication, number of citations, institution and country of origin, year of publication, study type, keywords, theme and subtheme, and international collaborations. The results showed the 50 top-cited articles were cited between 24 and 146 times each. The majority of these top-cited articles (n=34) were published in the Journal of Dental Education. Half (n=25) of the articles were by authors in the U.S. The most common study types were surveys (n=26) and reviews (n=10). The main themes of these top-cited articles were curriculum and learner characteristics. This bibliometric analysis can serve as a reference for recognizing studies with the most impact in the scholarship of dental education. Full Article
article SSO and other putative inhibitors of FA transport across membranes by CD36 disrupt intracellular metabolism, but do not affect FA translocation [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:28-07:00 Membrane-bound proteins have been proposed to mediate the transport of long-chain FA (LCFA) transport through the plasma membrane (PM). These proposals are based largely on reports that PM transport of LCFAs can be blocked by a number of enzymes and purported inhibitors of LCFA transport. Here, using the ratiometric pH indicator (2',7'-bis-(2-carboxyethyl)-5-(and-6-)-carboxyfluorescein and acrylodated intestinal FA-binding protein-based dual fluorescence assays, we investigated the effects of nine inhibitors of the putative FA transporter protein CD36 on the binding and transmembrane movement of LCFAs. We particularly focused on sulfosuccinimidyl oleate (SSO), reported to be a competitive inhibitor of CD36-mediated LCFA transport. Using these assays in adipocytes and inhibitor-treated protein-free lipid vesicles, we demonstrate that rapid LCFA transport across model and biological membranes remains unchanged in the presence of these purported inhibitors. We have previously shown in live cells that CD36 does not accelerate the transport of unesterified LCFAs across the PM. Our present experiments indicated disruption of LCFA metabolism inside the cell within minutes upon treatment with many of the "inhibitors" previously assumed to inhibit LCFA transport across the PM. Furthermore, using confocal microscopy and a specific anti-SSO antibody, we found that numerous intracellular and PM-bound proteins are SSO-modified in addition to CD36. Our results support the hypothesis that LCFAs diffuse rapidly across biological membranes and do not require an active protein transporter for their transmembrane movement. Full Article
article Hepatic monoamine oxidase B is involved in endogenous geranylgeranoic acid synthesis in mammalian liver cells [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:28-07:00 Geranylgeranoic acid (GGA) originally was identified in some animals and has been developed as an agent for preventing second primary hepatoma. We previously have also identified GGA as an acyclic diterpenoid in some medicinal herbs. Recently, we reported that in human hepatoma-derived HuH-7 cells, GGA is metabolically labeled from 13C-mevalonate. Several cell-free experiments have demonstrated that GGA is synthesized through geranylgeranial by oxygen-dependent oxidation of geranylgeraniol (GGOH), but the exact biochemical events giving rise to GGA in hepatoma cells remain unclear. Monoamine oxidase B (MOAB) has been suggested to be involved in GGOH oxidation. Here, using two human hepatoma cell lines, we investigated whether MAOB contributes to GGA biosynthesis. Using either HuH-7 cell lysates or recombinant human MAOB, we found that: 1) the MAO inhibitor tranylcypromine dose-dependently downregulates endogenous GGA levels in HuH-7 cells; and 2) siRNA-mediated MAOB silencing reduces intracellular GGA levels in HuH-7 and Hep3B cells. Unexpectedly, however, CRISPR/Cas9-generated MAOB-KO human hepatoma Hep3B cells had GGA levels similar to those in MAOB-WT cells. A sensitivity of GGA levels to siRNA-mediated MAOB downregulation was recovered when the MAOB-KO cells were transfected with a MAOB-expression plasmid, suggesting that MAOB is the enzyme primarily responsible for GGOH oxidation and that some other latent metabolic pathways may maintain endogenous GGA levels in the MAOB-KO hepatoma cells. Along with the previous findings, these results provide critical insights into the biological roles of human MAOB and provide evidence that hepatic MAOB is involved in endogenous GGA biosynthesis via GGOH oxidation. Full Article
article A novel GPER antagonist protects against the formation of estrogen-induced cholesterol gallstones in female mice [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 Many clinical studies and epidemiological investigations have clearly demonstrated that women are twice as likely to develop cholesterol gallstones as men, and oral contraceptives and other estrogen therapies dramatically increase that risk. Further, animal studies have revealed that estrogen promotes cholesterol gallstone formation through the estrogen receptor (ER) α, but not ERβ, pathway. More importantly, some genetic and pathophysiological studies have found that G protein-coupled estrogen receptor (GPER) 1 is a new gallstone gene, Lith18, on chromosome 5 in mice and produces additional lithogenic actions, working independently of ERα, to markedly increase cholelithogenesis in female mice. Based on computational modeling of GPER, a novel series of GPER-selective antagonists were designed, synthesized, and subsequently assessed for their therapeutic effects via calcium mobilization, cAMP, and ERα and ERβ fluorescence polarization binding assays. From this series of compounds, one new compound, 2-cyclohexyl-4-isopropyl-N-(4-methoxybenzyl)aniline (CIMBA), exhibits superior antagonism and selectivity exclusively for GPER. Furthermore, CIMBA reduces the formation of 17β-estradiol-induced gallstones in a dose-dependent manner in ovariectomized mice fed a lithogenic diet for 8 weeks. At 32 μg/day/kg CIMBA, no gallstones are found, even in ovariectomized ERα (–/–) mice treated with 6 μg/day 17β-estradiol and fed the lithogenic diet for 8 weeks. In conclusion, CIMBA treatment protects against the formation of estrogen-induced cholesterol gallstones by inhibiting the GPER signaling pathway in female mice. CIMBA may thus be a new agent for effectively treating cholesterol gallstone disease in women. Full Article
article Nanodomains can persist at physiologic temperature in plasma membrane vesicles and be modulated by altering cell lipids [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 The formation and properties of liquid-ordered (Lo) lipid domains (rafts) in the plasma membrane are still poorly understood. This limits our ability to manipulate ordered lipid domain-dependent biological functions. Giant plasma membrane vesicles (GPMVs) undergo large-scale phase separations into coexisting Lo and liquid-disordered lipid domains. However, large-scale phase separation in GPMVs detected by light microscopy is observed only at low temperatures. Comparing Förster resonance energy transfer-detected versus light microscopy-detected domain formation, we found that nanodomains, domains of nanometer size, persist at temperatures up to 20°C higher than large-scale phases, up to physiologic temperature. The persistence of nanodomains at higher temperatures is consistent with previously reported theoretical calculations. To investigate the sensitivity of nanodomains to lipid composition, GPMVs were prepared from mammalian cells in which sterol, phospholipid, or sphingolipid composition in the plasma membrane outer leaflet had been altered by cyclodextrin-catalyzed lipid exchange. Lipid substitutions that stabilize or destabilize ordered domain formation in artificial lipid vesicles had a similar effect on the thermal stability of nanodomains and large-scale phase separation in GPMVs, with nanodomains persisting at higher temperatures than large-scale phases for a wide range of lipid compositions. This indicates that it is likely that plasma membrane nanodomains can form under physiologic conditions more readily than large-scale phase separation. We also conclude that membrane lipid substitutions carried out in intact cells are able to modulate the propensity of plasma membranes to form ordered domains. This implies lipid substitutions can be used to alter biological processes dependent upon ordered domains. Full Article
article Schnyder corneal dystrophy-associated UBIAD1 is defective in MK-4 synthesis and resists autophagy-mediated degradation [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 The autosomal dominant disorder Schnyder corneal dystrophy (SCD) is caused by mutations in UbiA prenyltransferase domain-containing protein-1 (UBIAD1), which uses geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4 (MK-4). SCD is characterized by opacification of the cornea, owing to aberrant build-up of cholesterol in the tissue. We previously discovered that sterols stimulate association of UBIAD1 with ER-localized HMG-CoA reductase, which catalyzes a rate-limiting step in the synthesis of cholesterol and nonsterol isoprenoids, including GGpp. Binding to UBIAD1 inhibits sterol-accelerated ER-associated degradation (ERAD) of reductase and permits continued synthesis of GGpp in cholesterol-replete cells. GGpp disrupts UBIAD1-reductase binding and thereby allows for maximal ERAD of reductase as well as ER-to-Golgi translocation of UBIAD1. SCD-associated UBIAD1 is refractory to GGpp-mediated dissociation from reductase and remains sequestered in the ER to inhibit ERAD. Here, we report development of a biochemical assay for UBIAD1-mediated synthesis of MK-4 in isolated membranes and intact cells. Using this assay, we compared enzymatic activity of WT UBIAD1 with that of SCD-associated variants. Our studies revealed that SCD-associated UBIAD1 exhibited reduced MK-4 synthetic activity, which may result from its reduced affinity for GGpp. Sequestration in the ER protects SCD-associated UBIAD1 from autophagy and allows intracellular accumulation of the mutant protein, which amplifies the inhibitory effect on reductase ERAD. These findings have important implications not only for the understanding of SCD etiology but also for the efficacy of cholesterol-lowering statin therapy, which becomes limited, in part, because of UBIAD1-mediated inhibition of reductase ERAD. Full Article
article Slc43a3 is a regulator of free fatty acid flux [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 Adipocytes take up long chain FAs through diffusion and protein-mediated transport, whereas FA efflux is considered to occur by diffusion. To identify potential membrane proteins that are involved in regulating FA flux in adipocytes, the expression levels of 55 membrane transporters without known function were screened in subcutaneous adipose samples from obese patients before and after bariatric surgery using branched DNA methodology. Among the 33 solute carrier (SLC) transporter family members screened, the expression of 14 members showed significant changes before and after bariatric surgery. One of them, Slc43a3, increased about 2.5-fold after bariatric surgery. Further investigation demonstrated that Slc43a3 is highly expressed in murine adipose tissue and induced during adipocyte differentiation in primary preadipocytes and in OP9 cells. Knockdown of Slc43a3 with siRNA in differentiated OP9 adipocytes reduced both basal and forskolin-stimulated FA efflux, while also increasing FA uptake and lipid droplet accumulation. In contrast, overexpression of Slc43a3 decreased FA uptake in differentiated OP9 cells and resulted in decreased lipid droplet accumulation. Therefore, Slc43a3 seems to regulate FA flux in adipocytes, functioning as a positive regulator of FA efflux and as a negative regulator of FA uptake. Full Article
article The grease trap: uncovering the mechanism of the hydrophobic lid in Cutibacterium acnes lipase [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 Acne is one of the most common dermatological conditions, but the details of its pathology are unclear, and current management regimens often have adverse effects. Cutibacterium acnes is known as a major acne-associated bacterium that derives energy from lipase-mediated sebum lipid degradation. C. acnes is commensal, but lipase activity has been observed to differ among C. acnes types. For example, higher populations of the type IA strains are present in acne lesions with higher lipase activity. In the present study, we examined a conserved lipase in types IB and II that was truncated in type IA C. acnes strains. Closed, blocked, and open structures of C. acnes ATCC11828 lipases were elucidated by X-ray crystallography at 1.6–2.4 Å. The closed crystal structure, which is the most common form in aqueous solution, revealed that a hydrophobic lid domain shields the active site. By comparing closed, blocked, and open structures, we found that the lid domain-opening mechanisms of C. acnes lipases (CAlipases) involve the lid-opening residues, Phe-179 and Phe-211. To the best of our knowledge, this is the first structure-function study of CAlipases, which may help to shed light on the mechanisms involved in acne development and may aid in future drug design. Full Article
article Vitamin E does not prevent Western diet-induced NASH progression and increases metabolic flux dysregulation in mice [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 Fatty liver involves ectopic lipid accumulation and dysregulated hepatic oxidative metabolism, which can progress to a state of elevated inflammation and fibrosis referred to as nonalcoholic steatohepatitis (NASH). The factors that control progression from simple steatosis to NASH are not fully known. Here, we tested the hypothesis that dietary vitamin E (VitE) supplementation would prevent NASH progression and associated metabolic alterations induced by a Western diet (WD). Hyperphagic melanocortin-4 receptor-deficient (MC4R–/–) mice were fed chow, chow+VitE, WD, or WD+VitE starting at 8 or 20 weeks of age. All groups exhibited extensive hepatic steatosis by the end of the study (28 weeks of age). WD feeding exacerbated liver disease severity without inducing proportional changes in liver triglycerides. Eight weeks of WD accelerated liver pyruvate cycling, and 20 weeks of WD extensively upregulated liver glucose and oxidative metabolism assessed by 2H/13C flux analysis. VitE supplementation failed to reduce the histological features of NASH. Rather, WD+VitE increased the abundance and saturation of liver ceramides and accelerated metabolic flux dysregulation compared with 8 weeks of WD alone. In summary, VitE did not limit NASH pathogenesis in genetically obese mice, but instead increased some indicators of metabolic dysfunction. Full Article
article Myeloid-specific deficiency of pregnane X receptor decreases atherosclerosis in LDL receptor-deficient mice [Research Articles] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 The pregnane X receptor (PXR) is a nuclear receptor that can be activated by numerous drugs and xenobiotic chemicals. PXR thereby functions as a xenobiotic sensor to coordinately regulate host responses to xenobiotics by transcriptionally regulating many genes involved in xenobiotic metabolism. We have previously reported that PXR has pro-atherogenic effects in animal models, but how PXR contributes to atherosclerosis development in different tissues or cell types remains elusive. In this study, we generated an LDL receptor-deficient mouse model with myeloid-specific PXR deficiency (PXRMyeLDLR–/–) to elucidate the role of macrophage PXR signaling in atherogenesis. The myeloid PXR deficiency did not affect metabolic phenotypes and plasma lipid profiles, but PXRMyeLDLR–/– mice had significantly decreased atherosclerosis at both aortic root and brachiocephalic arteries compared with control littermates. Interestingly, the PXR deletion did not affect macrophage adhesion and migration properties, but reduced lipid accumulation and foam cell formation in the macrophages. PXR deficiency also led to decreased expression of the scavenger receptor CD36 and impaired lipid uptake in macrophages of the PXRMyeLDLR–/– mice. Further, RNA-Seq analysis indicated that treatment with a prototypical PXR ligand affects the expression of many atherosclerosis-related genes in macrophages in vitro. These findings reveal a pivotal role of myeloid PXR signaling in atherosclerosis development and suggest that PXR may be a potential therapeutic target in atherosclerosis management. Full Article
article The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes [Thematic Reviews] By www.jlr.org Published On :: 2020-05-01T00:05:27-07:00 Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning. Full Article
article Snake Deltavirus Utilizes Envelope Proteins of Different Viruses To Generate Infectious Particles By mbio.asm.org Published On :: 2020-03-17T01:30:15-07:00 ABSTRACT Satellite viruses, most commonly found in plants, rely on helper viruses to complete their replication cycle. The only known example of a human satellite virus is the hepatitis D virus (HDV), and it is generally thought to require hepatitis B virus (HBV) to form infectious particles. Until 2018, HDV was the sole representative of the genus Deltavirus and was thought to have evolved in humans, the only known HDV host. The subsequent identification of HDV-like agents in birds, snakes, fish, amphibians, and invertebrates indicated that the evolutionary history of deltaviruses is likely much longer than previously hypothesized. Interestingly, none of the HDV-like agents were found in coinfection with an HBV-like agent, suggesting that these viruses use different helper virus(es). Here we show, using snake deltavirus (SDeV), that HBV and hepadnaviruses represent only one example of helper viruses for deltaviruses. We cloned the SDeV genome into a mammalian expression plasmid, and by transfection could initiate SDeV replication in cultured snake and mammalian cell lines. By superinfecting persistently SDeV-infected cells with reptarenaviruses and hartmaniviruses, or by transfecting their surface proteins, we could induce production of infectious SDeV particles. Our findings indicate that deltaviruses can likely use a multitude of helper viruses or even viral glycoproteins to form infectious particles. This suggests that persistent infections, such as those caused by arenaviruses and orthohantaviruses used in this study, and recurrent infections would be beneficial for the spread of deltaviruses. It seems plausible that further human or animal disease associations with deltavirus infections will be identified in the future. IMPORTANCE Deltaviruses need a coinfecting enveloped virus to produce infectious particles necessary for transmission to a new host. Hepatitis D virus (HDV), the only known deltavirus until 2018, has been found only in humans, and its coinfection with hepatitis B virus (HBV) is linked with fulminant hepatitis. The recent discovery of deltaviruses without a coinfecting HBV-like agent in several different taxa suggested that deltaviruses could employ coinfection by other enveloped viruses to complete their life cycle. In this report, we show that snake deltavirus (SDeV) efficiently utilizes coinfecting reptarena- and hartmaniviruses to form infectious particles. Furthermore, we demonstrate that cells expressing the envelope proteins of arenaviruses and orthohantaviruses produce infectious SDeV particles. As the envelope proteins are responsible for binding and infecting new host cells, our findings indicate that deltaviruses are likely not restricted in their tissue tropism, implying that they could be linked to animal or human diseases other than hepatitis. Full Article
article Induction of Protective Antiplague Immune Responses by Self-Adjuvanting Bionanoparticles Derived from Engineered Yersinia pestis [Microbial Immunity and Vaccines] By iai.asm.org Published On :: 2020-04-20T08:00:38-07:00 A Yersinia pestis mutant synthesizing an adjuvant form of lipid A (monophosphoryl lipid A, MPLA) displayed increased biogenesis of bacterial outer membrane vesicles (OMVs). To enhance the immunogenicity of the OMVs, we constructed an Asd-based balanced-lethal host-vector system that oversynthesized the LcrV antigen of Y. pestis, raised the amounts of LcrV enclosed in OMVs by the type II secretion system, and eliminated harmful factors like plasminogen activator (Pla) and murine toxin from the OMVs. Vaccination with OMVs containing MPLA and increased amounts of LcrV with diminished toxicity afforded complete protection in mice against subcutaneous challenge with 8 x 105 CFU (80,000 50% lethal dose [LD50]) and intranasal challenge with 5 x 103 CFU (50 LD50) of virulent Y. pestis. This protection was significantly superior to that resulting from vaccination with LcrV/alhydrogel or rF1-V/alhydrogel. At week 4 postimmunization, the OMV-immunized mice showed more robust titers of antibodies against LcrV, Y. pestis whole-cell lysate (YPL), and F1 antigen and more balanced IgG1:IgG2a/IgG2b-derived Th1 and Th2 responses than LcrV-immunized mice. Moreover, potent adaptive and innate immune responses were stimulated in the OMV-immunized mice. Our findings demonstrate that self-adjuvanting Y. pestis OMVs provide a novel plague vaccine candidate and that the rational design of OMVs could serve as a robust approach for vaccine development. Full Article
article Articles of Significant Interest in This Issue [Spotlight] By jvi.asm.org Published On :: 2020-05-04T08:00:46-07:00 Full Article
article NRF3-POMP-20S Proteasome Assembly Axis Promotes Cancer Development via Ubiquitin-Independent Proteolysis of p53 and Retinoblastoma Protein [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Proteasomes are essential protease complexes that maintain cellular homeostasis, and aberrant proteasomal activity supports cancer development. The regulatory mechanisms and biological function of the ubiquitin-26S proteasome have been studied extensively, while those of the ubiquitin-independent 20S proteasome system remain obscure. Here, we show that the cap ’n’ collar (CNC) family transcription factor NRF3 specifically enhances 20S proteasome assembly in cancer cells and that 20S proteasomes contribute to colorectal cancer development through ubiquitin-independent proteolysis of the tumor suppressor p53 and retinoblastoma (Rb) proteins. The NRF3 gene is highly expressed in many cancer tissues and cell lines and is important for cancer cell growth. In cancer cells, NRF3 upregulates the assembly of the 20S proteasome by directly inducing the gene expression of the 20S proteasome maturation protein POMP. Interestingly, NRF3 knockdown not only increases p53 and Rb protein levels but also increases p53 activities for tumor suppression, including cell cycle arrest and induction of apoptosis. Furthermore, protein stability and cell viability assays using two distinct proteasome inhibitor anticancer drugs, the 20S proteasome inhibitor bortezomib and the ubiquitin-activating enzyme E1 inhibitor TAK-243, show that the upregulation of the NRF3-POMP axis leads to ubiquitin-independent proteolysis of p53 and Rb and to impaired sensitivity to bortezomib but not TAK-243. More importantly, the NRF3-POMP axis supports tumorigenesis and metastasis, with higher NRF3/POMP expression levels correlating with poor prognoses in patients with colorectal or rectal adenocarcinoma. These results suggest that the NRF3-POMP-20S proteasome assembly axis is significant for cancer development via ubiquitin-independent proteolysis of tumor suppressor proteins. Full Article
article Requirement of the Cep57-Cep63 Interaction for Proper Cep152 Recruitment and Centriole Duplication [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Cep57 has been characterized as a component of a pericentriolar complex containing Cep63 and Cep152. Interestingly, Cep63 and Cep152 self-assemble into a pericentriolar cylindrical architecture, and this event is critical for the orderly recruitment of Plk4, a key regulator of centriole duplication. However, the way in which Cep57 interacts with the Cep63-Cep152 complex and contributes to the structure and function of Cep63-Cep152 self-assembly remains unknown. We demonstrate that Cep57 interacts with Cep63 through N-terminal motifs and associates with Cep152 via Cep63. Three-dimensional structured illumination microscopy (3D-SIM) analyses suggested that the Cep57-Cep63-Cep152 complex is concentrically arranged around a centriole in a Cep57-in and Cep152-out manner. Cep57 mutant cells defective in Cep63 binding exhibited improper Cep63 and Cep152 localization and impaired Sas6 recruitment for procentriole assembly, proving the significance of the Cep57-Cep63 interaction. Intriguingly, Cep63 fused to a microtubule (MT)-binding domain of Cep57 functioned in concert with Cep152 to assemble around stabilized MTs in vitro. Thus, Cep57 plays a key role in architecting the Cep63-Cep152 assembly around centriolar MTs and promoting centriole biogenesis. This study may offer a platform to investigate how the organization and function of the pericentriolar architecture are altered by disease-associated mutations found in the Cep57-Cep63-Cep152 complex. Full Article
article E2F6-Mediated Downregulation of MIR22HG Facilitates the Progression of Laryngocarcinoma by Targeting the miR-5000-3p/FBXW7 Axis [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Recently, abundant evidence has clarified that long noncoding RNAs (lncRNAs) play an oncogenic or anticancer role in the tumorigenesis and development of diverse human cancers. Described as a crucial regulator in some cancers, MIR22HG has not yet been studied in laryngocarcinoma and therefore the underlying regulatory role of MIR22HG in laryngocarcinoma is worth detecting. In this study, MIR22HG expression in laryngocarcinoma cells was confirmed to be downregulated, and upregulated MIR22HG expression led to suppressive effects on laryngocarcinoma cell proliferation and migration. Molecular mechanism assays revealed that MIR22HG sponges miR-5000-3p in laryngocarcinoma cells. Besides, decreased expression of miR-5000-3p suppressed laryngocarcinoma cell proliferation and migration. Moreover, the FBXW7 gene was reported to be a downstream target gene of miR-5000-3p in laryngocarcinoma cells. More importantly, rescue assays verified that FBXW7 depletion or miR-5000-3p upregulation countervailed the repressive effects of MIR22HG overexpression on laryngocarcinoma progression. In addition, E2F6 was proved to be capable of inhibiting MIR22HG transcription in laryngocarcinoma cells. To sum up, E2F6-induced downregulation of MIR22HG promotes laryngocarcinoma progression through the miR-5000-3p/FBXW7 axis. Full Article
article AKT Regulates Mitotic Progression of Mammalian Cells by Phosphorylating MASTL, Leading to Protein Phosphatase 2A Inactivation [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Microtubule-associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl) kinase, has an important role in the regulation of mitosis. By inhibiting protein phosphatase 2A (PP2A), it plays a crucial role in activating one of the most important mitotic kinases, known as cyclin-dependent kinase 1 (CDK1). MASTL has been seen to be upregulated in various types of cancers and is also involved in tumor recurrence. It is activated by CDK1 through phosphorylations in the activation/T-loop, but the complete mechanism of its activation is still unclear. Here, we report that AKT phosphorylates MASTL at residue T299, which plays a critical role in its activation. Our results suggest that AKT increases CDK1-mediated phosphorylation and hence the activity of MASTL, which, in turn, promotes mitotic progression through PP2A inhibition. We also show that the oncogenic potential of AKT is augmented by MASTL activation, since AKT-mediated proliferation in colorectal cell lines can be attenuated by inhibiting and/or silencing MASTL. In brief, we report that AKT plays an important role in the progression of mitosis in mammalian cells and that it does so through the phosphorylation and activation of MASTL. Full Article
article Articles of Significant Interest in This Issue [Spotlight] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 Full Article
article Determining the Bioenergetic Capacity for Fatty Acid Oxidation in the Mammalian Nervous System [Research Article] By mcb.asm.org Published On :: 2020-04-28T08:00:17-07:00 The metabolic state of the brain can greatly impact neurologic function. Evidence of this includes the therapeutic benefit of a ketogenic diet in neurologic diseases, including epilepsy. However, brain lipid bioenergetics remain largely uncharacterized. The existence, capacity, and relevance of mitochondrial fatty acid β-oxidation (FAO) in the brain are highly controversial, with few genetic tools available to evaluate the question. We have provided evidence for the capacity of brain FAO using a pan-brain-specific conditional knockout (KO) mouse incapable of FAO due to the loss of carnitine palmitoyltransferase 2, the product of an obligate gene for FAO (CPT2B–/–). Loss of central nervous system (CNS) FAO did not result in gross neuroanatomical changes or systemic differences in metabolism. Loss of CPT2 in the brain did not result in robustly impaired behavior. We demonstrate by unbiased and targeted metabolomics that the mammalian brain oxidizes a substantial quantity of long-chain fatty acids in vitro and in vivo. Loss of CNS FAO results in robust accumulation of long-chain acylcarnitines in the brain, suggesting that the mammalian brain mobilizes fatty acids for their oxidation, irrespective of diet or metabolic state. Together, these data demonstrate that the mammalian brain oxidizes fatty acids under normal circumstances with little influence from or on peripheral tissues. Full Article
article Increasing Article Visibility: JABFM and Author Responsibilities and Possibilities By www.jabfm.org Published On :: 2020-03-16T09:31:37-07:00 JABFM seeks to widely disseminate its peer-reviewed publications, increasing article visibility for the purpose of advancing scientific knowledge. We describe the journal’s approach to dissemination and recommend a number of strategies for authors to implement, including press releases and social media. Providing the article’s digital object identifier (DOI) is most useful, compared with links that can break, or attaching the article PDF, which will depress reader metrics. All JABFM articles are freely accessible online worldwide. Full Article
article The glue produced by Drosophila melanogaster for pupa adhesion is universal [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-23T02:38:05-07:00 Flora Borne, Alexander Kovalev, Stanislav Gorb, and Virginie Courtier-Orgogozo Insects produce a variety of adhesives for diverse functions such as locomotion, mating, and egg or pupal anchorage to substrates. Although they are important for the biology of organisms and potentially represent a great resource for developing new materials, insect adhesives have been little studied so far. Here, we examined the adhesive properties of the larval glue of Drosophila melanogaster. This glue is made of glycosylated proteins and allows the animal to adhere to a substrate during metamorphosis. We designed an adhesion test to measure the pull-off force required to detach a pupa from a substrate and to evaluate the contact area covered by the glue. We found that the pupa adheres with similar forces to a variety of substrates (with distinct roughness, hydrophilic and charge properties). We obtained an average pull-off force of 217 mN, corresponding to 15,500 times the weight of a pupa and an adhesion strength of 137–244 kPa. Surprisingly, the pull-off forces did not depend on the contact area. Our study paves the way for a genetic dissection of the components of D. melanogaster glue that confer its particular adhesive properties. Full Article
article Microclimate buffering and thermal tolerance across elevations in a tropical butterfly [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-16T05:35:47-07:00 Gabriela Montejo-Kovacevich, Simon H. Martin, Joana I. Meier, Caroline N. Bacquet, Monica Monllor, Chris D. Jiggins, and Nicola J. Nadeau Microclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Nonetheless, currently available climatic datasets lack data from the forest interior and, furthermore, our knowledge of thermal tolerance among tropical ectotherms is limited. We therefore studied natural variation in the microclimate experienced by tropical butterflies in the genus Heliconius across their Andean range in a single year. We found that the forest strongly buffers temperature and humidity in the understorey, especially in the lowlands, where temperatures are more extreme. There were systematic differences between our yearly records and macroclimate databases (WorldClim2), with lower interpolated minimum temperatures and maximum temperatures higher than expected. We then assessed thermal tolerance of 10 Heliconius butterfly species in the wild and found that populations at high elevations had significantly lower heat tolerance than those at lower elevations. However, when we reared populations of the widespread H. erato from high and low elevations in a common-garden environment, the difference in heat tolerance across elevations was reduced, indicating plasticity in this trait. Microclimate buffering is not currently captured in publicly available datasets, but could be crucial for enabling upland shifting of species sensitive to heat such as highland Heliconius. Plasticity in thermal tolerance may alleviate the effects of global warming on some widespread ectotherm species, but more research is needed to understand the long-term consequences of plasticity on populations and species. Full Article
article Body surface temperature responses to food restriction in wild and captive great tits [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-20T16:00:19-07:00 Lucy A. Winder, Stewart A. White, Andreas Nord, Barbara Helm, and Dominic J. McCafferty During winter at temperate and high latitudes, the low ambient temperatures, limited food supplies and short foraging periods mean small passerines show behavioural, morphological and physiological adaptations to reduce the risk of facing energy shortages. Peripheral tissues vasoconstrict in low ambient temperatures to reduce heat loss and cold injury. Peripheral vasoconstriction has been observed with food restriction in captivity but has yet to be explored in free-ranging animals. We experimentally food restricted both wild and captive great tits (Parus major) during winter months and measured surface temperatures of the bill and eye region using thermal imaging, to investigate whether birds show rapid local heterothermic responses, which may reduce their thermoregulatory costs when facing a perceived imminent food shortage. Our results of a continuously filmed wild population showed that bill temperature was immediately reduced in response to food restriction compared with when food was available ad libitum, an apparent autonomic response. Such immediacy implies a ‘pre-emptive’ response before the bird experiences any shortfalls in energy reserves. We also demonstrate temporal variation in vasoconstriction of the bill, with bill temperature gradually rising throughout the food restriction after the initial drop. Eye-region temperature in the wild birds remained at similar levels throughout food restriction compared with unrestricted birds, possibly reflecting the need to maintain steady circulation to the central nervous and visual systems. Our findings provide evidence that birds selectively allow the bill to cool when a predictable food supply is suddenly disrupted, probably as a means of minimising depletion of body reserves for a perceived future shortage in energy. Full Article
article Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-16T05:19:55-07:00 Fredrik Andreasson, Arne Hegemann, Andreas Nord, and Jan-Ake Nilsson The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared with unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction. Full Article
article Habituation of the cardiovascular response to restraint stress is inhibited by exposure to other stressor stimuli and exercise training [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-23T22:21:31-07:00 Ricardo Benini, Leandro A. Oliveira, Lucas Gomes-de-Souza, Bruno Rodrigues, and Carlos C. Crestani This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as treadmill exercise training, in the habituation of the cardiovascular response upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted for 10 consecutive days, whereas treadmill training was performed for 1 h per day, 5 days per week for 8 weeks. We observed that the increase in serum corticosterone was reduced during both the stress and the recovery period of the 10th session of restraint. Habituation of the cardiovascular response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation or treadmill exercise training inhibited the habituation of the restraint-evoked tachycardia. Additionally, CVS increased the blood pressure response at the 10th session of restraint, whereas social isolation enhanced both the tachycardia during the first session and the drop in skin temperature at the 10th session of restraint. Taken together, these findings provide new evidence that pathologies evoked by stress might be related to impairment in the habituation process to homotypic stressors. Full Article
article Reduced immune responsiveness contributes to winter energy conservation in an Arctic bird [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-27T15:00:22-07:00 Andreas Nord, Arne Hegemann, and Lars P. Folkow Animals in seasonal environments must prudently manage energy expenditure to survive the winter. This may be achieved through reductions in the allocation of energy for various purposes (e.g. thermoregulation, locomotion, etc.). We studied whether such trade-offs also include suppression of the innate immune response, by subjecting captive male Svalbard ptarmigan (Lagopus muta hyperborea) to bacterial lipopolysaccharide (LPS) during exposure to either mild temperature (0°C) or cold snaps (acute exposure to –20°C), in constant winter darkness when birds were in energy-conserving mode, and in constant daylight in spring. The innate immune response was mostly unaffected by temperature. However, energy expenditure was below baseline when birds were immune challenged in winter, but significantly above baseline in spring. This suggests that the energetic component of the innate immune response was reduced in winter, possibly contributing to energy conservation. Immunological parameters decreased (agglutination, lysis, bacteriostatic capacity) or did not change (haptoglobin/PIT54) after the challenge, and behavioural modifications (anorexia, mass loss) were lengthy (9 days). While we did not study the mechanisms explaining these weak, or slow, responses, it is tempting to speculate they may reflect the consequences of having evolved in an environment where pathogen transmission rate is presumably low for most of the year. This is an important consideration if climate change and increased exploitation of the Arctic would alter pathogen communities at a pace outwith counter-adaption in wildlife. Full Article
article Consequences of being phenotypically mismatched with the environment: no evidence of oxidative stress in cold- and warm-acclimated birds facing a cold spell [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-14T02:37:46-07:00 Ana Gabriela Jimenez, Emily Cornelius Ruhs, Kailey J. Tobin, Katie N. Anderson, Audrey Le Pogam, Lyette Regimbald, and Francois Vezina Seasonal changes in maximal thermogenic capacity (Msum) in wild black-capped chickadees suggests that adjustments in metabolic performance are slow and begin to take place before winter peaks. However, when mean minimal ambient temperature (Ta) reaches –10°C, the chickadee phenotype appears to provide enough spare capacity to endure days with colder Ta, down to –20°C or below. This suggests that birds could also maintain a higher antioxidant capacity as part of their cold-acclimated phenotype to deal with sudden decreases in temperature. Here, we tested how environmental mismatch affected oxidative stress by comparing cold-acclimated (–5°C) and transition (20°C) phenotypes in chickadees exposed to an acute 15°C drop in temperature with that of control individuals. We measured superoxide dismutase, catalase and glutathione peroxidase activities, as well as lipid peroxidation damage and antioxidant scavenging capacity in pectoralis muscle, brain, intestine and liver. We generally found differences between seasonal phenotypes and across tissues, but no differences with respect to an acute cold drop treatment. Our data suggest oxidative stress is closely matched to whole-animal physiology in cold-acclimated birds compared with transition birds, implying that changes to the oxidative stress system happen slowly. Full Article
article Temperature has a causal and plastic effect on timing of breeding in a small songbird [RESEARCH ARTICLE] By jeb.biologists.org Published On :: 2020-04-23T10:58:53-07:00 Irene Verhagen, Barbara M. Tomotani, Phillip Gienapp, and Marcel E. Visser Phenotypic plasticity is an important mechanism by which an individual can adapt its seasonal timing to predictable, short-term environmental changes by using predictive cues. Identification of these cues is crucial to forecast the response of species to long-term environmental change and to study their potential to adapt. Individual great tits (Parus major) start reproduction early under warmer conditions in the wild, but whether this effect is causal is not well known. We housed 36 pairs of great tits in climate-controlled aviaries and 40 pairs in outdoor aviaries, where they bred under artificial contrasting temperature treatments or in semi-natural conditions, respectively, for two consecutive years, using birds from lines selected for early and late egg laying. We thus obtained laying dates in two different thermal environments for each female. Females bred earlier under warmer conditions in climate-controlled aviaries, but not in outdoor aviaries. The latter was inconsistent with laying dates from our wild population. Further, early selection line females initiated egg laying consistently ~9 days earlier than late selection line females in outdoor aviaries, but we found no difference in the degree of plasticity (i.e. the sensitivity to temperature) in laying date between selection lines. Because we found that temperature causally affects laying date, climate change will lead to earlier laying. This advancement is, however, unlikely to be sufficient, thereby leading to selection for earlier laying. Our results suggest that natural selection may lead to a change in mean phenotype, but not to a change in the sensitivity of laying dates to temperature. Full Article