Electrical Pulse Stimulation of Cultured Human Skeletal Muscle Cells as an In Vitro Model of Exercise

Background and Aims Physical exercise leads to substantial adaptive responses in skeletal muscles and plays a central role in a healthy life style. Since exercise induces major systemic responses, underlying cellular mechanisms are difficult to study in vivo. It was therefore desirable to develop an in vitro model that would resemble training in cultured human myotubes. Methods Electrical pulse stimulation (EPS) was applied to adherent human myotubes. Cellular contents of ATP, phosphocreatine (PCr) and lactate were determined. Glucose and oleic acid metabolism were studied using radio-labeled substrates, and gene expression was analyzed using real-time RT-PCR. Mitochondrial content and function were measured by live imaging and determination of citrate synthase activity, respectively. Protein expression was assessed by electrophoresis and immunoblotting. Results High-frequency, acute EPS increased deoxyglucose uptake and lactate production, while cell contents of both ATP and PCr decreased. Chronic, low-frequency EPS increased oxidative capacity of cultured myotubes by increasing glucose metabolism (uptake and oxidation) and complete fatty acid oxidation. mRNA expression level of pyruvate dehydrogenase complex 4 (PDK4) was significantly increased in EPS-treated cells, while mRNA expressions of interleukin 6 (IL-6), cytochrome C and carnitin palmitoyl transferase b (CPT1b) also tended to increase. Intensity of MitoTracker®Red FM was doubled after 48 h of chronic, low-frequency EPS. Protein expression of a slow fiber type marker (MHCI) was increased in EPS-treated cells. Conclusions Our results imply that in vitro EPS (acute, high-frequent as well as chronic, low-frequent) of human myotubes may be used to study effects of exercise.This work was funded by the University of Oslo, Oslo University College, the Norwegian Diabetes Foundation, the Freia Chocolade Fabriks Medical Foundation and the Anders Jahre’s Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Prospect and potential of Burkholderia sp. against Phytophthora capsici Leonian: a causative agent for foot rot disease of black pepper

Foot rot disease is a very destructive disease in black pepper in Malaysia. It is caused by Phytophthora capsici Leonian, which is a soilborne pathogenic protist (phylum, Oomycota) that infects aerial and subterranean structures of many host plants. This pathogen is a polycyclic, such that multiple cycles of infection and inoculum production occur in a single growing season. It is more prevalent in the tropics because of the favourable environmental conditions. The utilization of plant growth-promoting rhizobacteria (PGPR) as a biological control agent has been successfully implemented in controlling many plant pathogens. Many studies on the exploration of beneficial organisms have been carried out such as Pseudomonas fluorescens, which is one of the best examples used for the control of Fusarium wilt in tomato. Similarly, P. fluorescens is found to be an effective biocontrol agent against the foot rot disease in black pepper. Nowadays there is tremendous novel increase in the species of Burkholderia with either mutualistic or antagonistic interactions in the environment. Burkholderia sp. is an indigenous PGPR capable of producing a large number of commercially important hydrolytic enzymes and bioactive substances that promote plant growth and health; are eco-friendly, biodegradable and specific in their actions; and have a broad spectrum of antimicrobial activity in keeping down the population of phytopathogens, thus playing a great role in promoting sustainable agriculture today. Hence, in this book chapter, the potential applications of Burkholderia sp. to control foot rot disease of black pepper in Malaysia, their control mechanisms, plant growth promotion, commercial potentials and the future prospects as indigenous PGPR were discussed in relation to sustainable agriculture

Bemerkungen zu Papyri XXXI: 855–885

<Korr. Tyche> 855–885<Korr. Tyche> 855–88

CH₄, N₂O, CO₂ eq. and NH₃ production (average ± standard deviation) per kilogram of bodymass per day for <i>five insect species</i>, pigs and beef cattle.

<p>BM = Body Mass;</p><p>N/A = Not Available;</p><p>Reported values for pigs and beef cattle were obtained from: <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Aarnink1" target="_blank">[5]</a> Aarnink et al., 1995; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-GrootKoerkamp1" target="_blank">[49]</a> Groot Koerkamp et al., 1998; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Demmers2" target="_blank">[52]</a> Demmers et al., 2001; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Nicks1" target="_blank">[50]</a> Nicks et al., 2003; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Beauchemin1" target="_blank">[59]</a> Beauchemin & McGinn, 2005; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Cabaraux1" target="_blank">[48]</a> Cabaraux et al., 2009 and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0014445#pone.0014445-Harper1" target="_blank">[53]</a> Harper et al., 2009. Mean values bearing different superscripts in a column differ significantly (P<0.05).</p

Mean values and standard deviations of temperature, humidity, ventilation, hours of light per day and average start and final weight for five insect species.

<p>Mean values and standard deviations of temperature, humidity, ventilation, hours of light per day and average start and final weight for five insect species.</p

CO₂ production (g) per kilogram of metabolic weight per day for five insect species, pigs and beef cattle based on Kleiber's law (B = aM^b).

<p>CO₂ production (g) per kilogram of metabolic weight per day for five insect species, pigs and beef cattle based on Kleiber's law (B = aM^b).</p

Calculated CO₂ production of provided feed for five insect species recalculated per kg of animal body mass.

<p>Calculated CO₂ production of provided feed for five insect species recalculated per kg of animal body mass.</p