Identical responses of fast muscle to sustained activity by low-frequency stimulation in young and aging rats

Toinvestigate effects of sustained activity on major phenotypicproperties, the left extensor digitorum longus muscle of young (15 wk)and aging (101 wk) male Brown Norway rats was subjected to 50 days ofchronic low-frequency stimulation (CLFS; 10 Hz, 10 h/day).The contralateral muscle served as control. Changes in metabolicenzymes were analyzed by using glyceraldehyde-3-phosphate dehydrogenaseand lactate dehydrogenase as reference enzymes of glycolysis and byusing citrate synthase and 3-hydroxyacyl-CoA dehydrogenase asmitochondrial enzymes representative of aerobic-oxidative metabolism. Myosin heavy chain (MHC) isoforms wereanalyzed by SDS-PAGE. No differences existed between the enzymeactivity profiles of control muscles from young and aging rats. CLFSinduced similar increases in mitochondrial enzymes, as well as similardecreases in glycolytic enzymes. Although the MHC composition of thecontrol muscles in the aging rats displayed a shift toward slowerisoforms, the ultimate changes induced by CLFS led to nearly identicalMHC phenotypes in both young and aging rats. These results demonstrate an unaltered adaptability of skeletal muscle to increased neuromuscular activity in the aging rat.

     

Biodiesel synthesis at high pressure and temperature: Analysis of energy consumption on industrial scale

Analysis of several different schemes for industrial FAME production at higher pressure and temperature (catalytic or non-catalytic synthesis) was realized with the aim to find the best route to reduce the energy consumption (EC) and to improve the life cycle energy efficiency. Obtained results indicated that the EC (MJ/kg FAME) mainly depends on degree of conversion of triglycerides being almost 25% smaller if degree of conversion increase from 97 mass% to complete conversion. Further significant decrease of EC might be obtained at subcritical conditions but only after substantial decrease of methanol to oil molar ratio (from 42 to 15) which requires use of appropriate catalyst. On account of that, the kinetics of heterogeneous catalyzed methanolysis of triglycerides was analyzed using data published in literature (CaO) as well as own experimental data (K₂CO₃/Al–O–Si) with a goal to obtain reliable kinetic rate constant which might be used for process simulation.This study shows that if heterogeneous process of biodiesel synthesis is realized at subcritical conditions then further decrease of EC is possible.     

β-1,3-glucanase class III promotes spread of PVYNTN and improves in planta protein production

Glucanases are enzymes regulating the size exclusion limit and permeability of plasmodesmata and play a role in biotic stress. In plant genomes, they are encoded as relatively large gene families divided into four classes. Most studies of plant virus interactions have focused on glucanases from classes I and II. In our study, we have evaluated the role of the β-1,3-glucanase class III (Glu-III) gene in the potato–potato virus Y^NTN (PVY^NTN) interaction and implemented the findings to plant biotechnology application. Potato cultivars Désirée and Santé, which are tolerant and extremely resistant to PVY^NTN, respectively, were stably transformed with Agrobacterium tumefaciens harbouring constructs for Glu-III overexpression. Localization of Glu-III protein in patches within the cell wall was determined by tagging the Glu-III protein with green fluorescent protein. Transgenic and non-transgenic plants were challenged with PVY^NTN and its multiplication and spreading was followed. Differences in viral spread were observed between transgenic lines overexpressing Glu-III and non-transgenic lines, with stronger and faster viral spread in transgenic Désirée, and some multiplication in transgenic Santé. In addition, the ability of Glu-III to improve in planta protein production after agroinfiltration was tested. The results have shown that Glu-III overexpression enables faster spreading of vectors between cells and better protein production, which could be beneficial in improving in planta protein production system using viral vectors.     

When Natural Behavior Engages Working Memory

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Sexual Activity and Reproductive Isolation Between Age‐specific Selected Populations of Seed Beetle

We evaluated the degree of reproductive isolation between laboratory populations of the seed beetle (Acanthoscelides obtectus) selected to reproduce early (E) or late (L) in life, where different levels of sexual activity and sexual discrimination have been detected. We found a significant level of behavioral isolation among populations within the E selection regime in which beetles showed enhanced early‐life fitness traits and low sexual activity. In contrast, substantially higher levels of sexual activity and an indiscriminate mating system inhibited rather than promoted pre‐zygotic isolation between the L populations. Our results indicate that the study of sexual activity levels may be crucial for understanding the first steps in the pre‐zygotic isolation among allopatric populations subjected to uniform selection.     

Population structure in a wheat core collection and genomic loci associated with yield under contrasting environments

A set of 96 winter wheat accessions sampled from a variety of geographic origins, including cultivars and breeding lines, were characterized with 46 genome-wide SSR loci for genetic diversity and population structure. The genetic diversity within these accessions was examined using a genetic distance-based and a model-based clustering method. The model-based analysis identified an underlying population structure comprising of four distinct sub-populations which corresponded well with distance-based groupings. Information on the population structure is taken into account in an association mapping study of grain yield from a 3-years field trial incorporating fully irrigated, rainfed and drought stress treatments. A total of 21 marker-grain yield associations (P?<?0.01) were identified with nine SSR markers. Most associations were detected only in one to three environments (treatment/year combination), with an average R ² value around 13?%. However, marker gwm484 (on chromosome 2D) was associated with yield in six environments, including irrigated, rainfed and drought stress treatments, suggesting it could be used to improve grain yield across a range of environments. Variation in grain yield at this locus was associated with earliness, early vigour, kernels per spikelet and harvest index. Microsatellite locus psp3200 (on chromosome 6D) was associated with yield in dry and hot environments, which was related to earliness, early vigour, productive tillering and total biomass per plant. Partial least squares regression, with nine environmental factors, showed that precipitation from tillering to maturity was the main environmental factor causing marker?×?environment associations for grain yield.