Fiber hypertrophy and increased oxidative capacity can occur simultaneously in pig glycolytic skeletal muscle

Scheffler, T. L.,Scheffler, J. M.,Park, S.,Kasten, S. C.,Wu, Y.,McMillan, R. P.,Hulver, M. W.,Frisard, M. I.,Gerrard, D. E. American Physiological Society 2014 American journal of physiology. Cell physiology Vol.306 No.4

<P>An inverse relationship between skeletal muscle fiber cross-sectional area (CSA) and oxidative capacity suggests that muscle fibers hypertrophy at the expense of oxidative capacity. Therefore, our objective was to utilize pigs possessing mutations associated with increased oxidative capacity [AMP-activated protein kinase (AMPKγ<SUB>3</SUB><SUP>R200Q</SUP>)] or fiber hypertrophy [ryanodine receptor 1 (RyR1<SUP>R615C</SUP>)] to determine if these events occur in parallel. Longissimus muscle was collected from wild-type (control), AMPKγ<SUB>3</SUB><SUP>R200Q</SUP>, RyR1<SUP>R615C</SUP>, and AMPKγ<SUB>3</SUB><SUP>R200Q</SUP>-RyR1<SUP>R615C</SUP> pigs. Regardless of AMPK genotype, RyR<SUP>R615C</SUP> increased fiber CSA by 35%. In contrast, AMPKγ<SUB>3</SUB><SUP>R200Q</SUP> pig muscle exhibited greater citrate synthase and β-hydroxyacyl CoA dehydrogenase activity. Isolated mitochondria from AMPKγ<SUB>3</SUB><SUP>R200Q</SUP> muscle had greater maximal, ADP-stimulated oxygen consumption rate. Additionally, AMPKγ<SUB>3</SUB><SUP>R200Q</SUP> muscle contained more (∼50%) of the mitochondrial proteins succinate dehydrogenase and cytochrome <I>c</I> oxidase and more mitochondrial DNA. Surprisingly, RyR1<SUP>R615C</SUP> increased mitochondrial proteins and DNA, but this was not associated with improved oxidative capacity, suggesting that altered energy metabolism in RyR1<SUP>R615C</SUP> muscle influences mitochondrial proliferation and protein turnover. Thus pigs that possess both AMPKγ3<SUP>R200Q</SUP> and RyR<SUP>R615C</SUP> exhibit increased muscle fiber CSA as well as greater oxidative capacity. Together, our findings support the notion that hypertrophy and enhanced oxidative capacity can occur simultaneously in skeletal muscle and suggest that the signaling mechanisms controlling these events are independently regulated.</P>

Unsteady Flow Field Investigations by Means of Digital Particle Image Velocimetry

H. Siekmann,T. Scheffler 대한기계학회 1997 International Conference on Fluid Machinery Vol.1 No.1

Electrospinning of nanofiber Chevrel phase materials

Woan, Karran V.,Scheffler, Raymond H.,Bell, Nelson S.,Sigmund, Wolfgang M. Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.24

<P>A modified sol–gel synthesis for non-oxide sulfide ceramics is presented. Sols are electrospun into continuous nanofiber precursors and then heat treated to obtain Chevrel-phase sulfide materials. In particular, the Mg-Chevrel fibers formed have average diameters of 230 ± 57 nm with grain sizes of 10 ± 3 nm after heat-treatment.</P> <P>Graphic Abstract</P><P>A modified sol–gel synthesis for non-oxide sulfide ceramics is presented. Sols are electrospun into continuous nanofiber Mg-Chevrel and Cu-Chevrel phase sulfide materials. The fibers formed have diameters of 100–300 nm with grain sizes of 10–30 nm after heat treatment. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1jm10378d'> </P>

Porcine satellite cells are restricted to a phenotype resembling their muscle origin

Zhu, H.,Park, S.,Scheffler, J. M.,Kuang, S.,Grant, A. L.,Gerrard, D. E. American Society of Animal Science 2013 Journal of animal science Vol.91 No.10

<P>Muscles in most domestic animals differ in function and growth potential based largely on muscle fiber type composition. Though much is known about satellite cells (SC), information is limited regarding how populations of SC differ with muscle fiber type, especially in pigs. Therefore, the objective of this study was to isolate and culture SC from red (RST) and white (WST) portions of the semitendinosus muscle of neonatal and adult pigs and determine their capacity to proliferate, differentiate, and express various myosin heavy chain (MyHC) isoforms in vitro. Porcine satellite cells were isolated from RST and WST muscles of 6-wk-old and adult (>6-mo-old) pigs and cultured under standard conditions. Muscle from neonatal pigs yielded nearly 10 times more (<I>P</I> < 0.001) presumptive satellite cells as those from adult pigs, with fusion percentages close to 60% for the former. The RST yielded more (<I>P</I> < 0.001) SC per gram muscle compared to WST, 8.1 ± 0.2 × 10<SUP>4</SUP> cells versus 6.7 ± 0.1 × 10<SUP>4</SUP> cells/gram muscle in young pigs, and 9.7 ± 0.4 × 10<SUP>3</SUP> cells versus 5.5 ± 0.4 × 10<SUP>3</SUP> cells/gram muscle in adult pigs, respectively. Likewise, satellite cells from RST proliferated faster (<I>P</I> < 0.001) than those from WST across both ages, as indicated by a shorter cell doubling time, 18.6 ± 0.8 h versus 21.3 ± 0.9 h in young pigs, and 23.2 ± 0.7 h versus 26.7 ± 0.9 h in adult pigs, respectively. As a result of shorter times to confluence, satellite cells from RST also formed myotubes earlier than those SC originating from WST. Once induced, however, SC from WST differentiated and fused faster (<I>P</I> < 0.05) as evidenced by fusion percentage within the first 24 h, 41.6% versus 34.3%, respectively; but reached similar ultimate fusion percentages similar to WST by 48 h. Over 90% of MyHC expressed in maximally fused SC cultures from both RST and WST was restricted to the embryonic isoform. Type IIX MyHC mRNA was not detected in any culture. Myotube cultures from RST expressed more (<I>P</I> < 0.01) Type I MyHC isoform mRNA than those from WST, whereas those cultures from WST expressed more (<I>P</I> < 0.05) Type II (including Types IIA and IIB) MyHC transcripts. These data show SC cultures from porcine fast and slow muscles express MyHC profiles largely reflective of their muscle of origin and suggest satellite cells are partially restricted to a particular muscle phenotype in which they are juxtapositioned. Understanding the molecular nature of these intrinsic control mechanisms may lead to improved strategies for augmenting meat animal growth or muscle regeneration.</P>

Electrospun materials for energy harvesting, conversion, and storage: A review

Laudenslager, Michael J.,Scheffler, Raymond H.,Sigmund, Wolfgang M. De Gruyter 2010 Pure and Applied Chemistry Vol.82 No.11

<P>Long-length nanofibers are able to form porous networks with high surface-area-to-volume ratios, and decrease diffusion lengths. While there are numerous techniques to create nanostructures, electrospinning is the only technique that allows fabrication of nanofibers at long-length scales. These uniquely shaped fibers are applied to several energy-related devices. This review is an in-depth summary of the uses of electrospun fibers in dye-sensitized solar cells (DSSCs), batteries, capacitors, fuel cells, and hydrogen storage devices. Developments in electrospinning technologies to create novel fiber morphologies are also discussed.</P>

Aflatoxin formation and gene expression in response to carbon source media shift in Aspergillus parasiticus

Wilkinson, J. R.,Yu, J.,Abbas, H. K.,Scheffler, B. E.,Kim, H. S.,Nierman, W. C.,Bhatnagar, D.,Cleveland, T. E. Taylor Francis 2007 Food additives and contaminants Vol.24 No.10

<P> Aflatoxins are toxic and carcinogenic polyketide metabolites produced by fungal species, including Aspergillus flavus and A. parasiticus. The biosynthesis of aflatoxins is modulated by many environmental factors, including the availability of a carbon source. The gene expression profile of A. parasiticus was evaluated during a shift from a medium with low concentration of simple sugars, yeast extract (YE), to a similar medium with sucrose, yeast extract sucrose (YES). Gene expression and aflatoxins (B1, B2, G1, and G2) were quantified from fungal mycelia harvested pre- and post-shifting. When compared with YE media, YES caused temporary reduction of the aflatoxin levels detected at 3-h post-shifting and they remained low well past 12 h post-shift. Aflatoxin levels did not exceed the levels in YE until 24 h post-shift, at which time point a tenfold increase was observed over YE. Microarray analysis comparing the RNA samples from the 48-h YE culture to the YES samples identified a total of 2120 genes that were expressed across all experiments, including most of the aflatoxin biosynthesis genes. One-way analysis of variance (ANOVA) identified 56 genes that were expressed with significant variation across all time points. Three genes responsible for converting norsolorinic acid to averantin were identified among these significantly expressed genes. The potential involvement of these genes in the regulation of aflatoxin biosynthesis is discussed.</P>

Benzene adsorbed on Si(001): The role of electron correlation and finite temperature

Kim, Hyun-Jung,Tkatchenko, Alexandre,Cho, Jun-Hyung,Scheffler, Matthias American Physical Society 2012 Physical review. B, Condensed matter and materials Vol.85 No.4

PKCε Promotes Oncogenic Functions of ATF2 in the Nucleus while Blocking Its Apoptotic Function at Mitochondria

Lau, E.,Kluger, H.,Varsano, T.,Lee, K.,Scheffler, I.,Rimm, David L.,Ideker, T.,Ronai, Ze'ev A. Cell Press ; MIT Press 2012 Cell Vol.148 No.3

The transcription factor ATF2 elicits oncogenic activities in melanoma and tumor suppressor activities in nonmalignant skin cancer. Here, we identify that ATF2 tumor suppressor function is determined by its ability to localize at the mitochondria, where it alters membrane permeability following genotoxic stress. The ability of ATF2 to reach the mitochondria is determined by PKCε, which directs ATF2 nuclear localization. Genotoxic stress attenuates PKCε effect on ATF2; enables ATF2 nuclear export and localization at the mitochondria, where it perturbs the HK1-VDAC1 complex; increases mitochondrial permeability; and promotes apoptosis. Significantly, high levels of PKCε, as seen in melanoma cells, block ATF2 nuclear export and function at the mitochondria, thereby attenuating apoptosis following exposure to genotoxic stress. In melanoma tumor samples, high PKCε levels associate with poor prognosis. Overall, our findings provide the framework for understanding how subcellular localization enables ATF2 oncogenic or tumor suppressor functions.

Wearable Sensor-Based Biometric Gait Classification Algorithm Using WEKA

Youn, Ik-Hyun,Won, Kwanghee,Youn, Jong-Hoon,Scheffler, Jeremy The Korea Institute of Information and Commucation 2016 Journal of information and communication convergen Vol.14 No.1

Gait-based classification has gained much interest as a possible authentication method because it incorporate an intrinsic personal signature that is difficult to mimic. The study investigates machine learning techniques to mitigate the natural variations in gait among different subjects. We incorporated several machine learning algorithms into this study using the data mining package called Waikato Environment for Knowledge Analysis (WEKA). WEKA's convenient interface enabled us to apply various sets of machine learning algorithms to understand whether each algorithm can capture certain distinctive gait features. First, we defined 24 gait features by analyzing three-axis acceleration data, and then selectively used them for distinguishing subjects 10 years of age or younger from those aged 20 to 40. We also applied a machine learning voting scheme to improve the accuracy of the classification. The classification accuracy of the proposed system was about 81% on average.