Dietary Enrichment with Fish Oil Prevents High Fat-Induced Metabolic Dysfunction in Skeletal Muscle in Mice

High saturated fat (HF-S) diets increase intramyocellular lipid, an effect ameliorated by omega-3 fatty acids in vitro and in vivo, though little is known about sex- and muscle fiber type-specific effects. We compared effects of standard chow, HF-S, and 7.5% HF-S replaced with fish oil (HF-FO) diets on the metabolic profile and lipid metabolism gene and protein content in red (soleus) and white (extensor digitorum longus) muscles of male and female C57BL/6 mice (n = 9-12/group). Weight gain was similar in HF-S- and HF-FO-fed groups. HF-S feeding increased mesenteric fat mass and lipid marker, Oil Red O, in red and mixed muscle; HF-FO increased interscapular brown fat mass. Compared to chow, HF-S and HF-FO increased expression of genes regulating triacylglycerol synthesis and fatty acid transport, HF-S suppressed genes and proteins regulating fatty acid oxidation, whereas HF-FO increased oxidative genes, proteins and enzymes and lipolytic gene content, whilst suppressing lipogenic genes. In comparison to HF-S, HF-FO further increased fat transporters, markers of fatty acid oxidation and mitochondrial content, and reduced lipogenic genes. No diet-by-sex interactions were observed. Neither diet influenced fiber type composition. However, some interactions between muscle type and diet were observed. HF-S induced changes in triacylglycerol synthesis and lipogenic genes in red, but not white, muscle, and mitochondrial biogenesis and oxidative genes were suppressed by HF-S and increased by HF-FO in red muscle only. In conclusion, HF-S feeding promotes lipid storage in red muscle, an effect abrogated by the fish oil, which increases mediators of lipolysis, oxidation and thermogenesis while inhibiting lipogenic genes. Greater storage and synthesis, and lower oxidative genes in red, but not white, muscle likely contribute to lipid accretion encountered in red muscle. Despite several gender-dimorphic genes, both sexes exhibited a similar HF-S-induced metabolic and gene expression profile; likewise fish oil was similarly protective in both sexes.     

Sarcosin (Krp1) in skeletal muscle differentiation: gene expression profiling and knockdown experiments

SARCOSIN, also named Krp1, has been identified as a protein exclusively expressed in striated muscle tissue. Here we report on the role of SARCOSIN in skeletal muscle development and differentiation. We demonstrate, by means of whole-mount in situ hybridization, that Sarcosin mRNA is expressed in the myotome part of the mature somites in mouse embryos from embryonic day 9.5 onwards. Sarcosin is not expressed in the developing heart at these embryonic stages, and in adult tissues the mRNA expression levels are five times lower in the heart than in skeletal muscle. SARCOSIN protein partially co-localizes with the M-band protein myomesin and between and below laterally fusing myofibrils in adult skeletal muscle tissue. RNA interference mediated knock-down of SARCOSIN in the C2C12 myoblast cell line appeared to be stimulatory in the early phase of differentiation, but inhibitory at a later phase of differentiation.     

Studies of the Cell Surface Properties of <Emphasis Type="Italic">Candida</Emphasis> Species and Relation to the Production of Biosurfactants for Environmental Applications

In practical bioremediation of petroleum pollution, treatment systems often use soil, sand, and other aquifer porous media besides water solutions. The distribution of the microbial cell also plays an important role in the whole process of bioremediation; therefore, the adhesion ability of cells to porous media is one of the key factors influencing the efficiency of treatment. The probable modes of hydrocarbon uptake in cells of Candida were studied based on data for cell hydrophobicity, emulsifying activity, surface tension, and interfacial tension of the cell-free culture medium. Six Candida strains were cultivated in insoluble and soluble substrates for 144 h, including n-hexadecane, soybean oil, ground-nut oil refinery residue, corn steep liquor, and glucose. The results obtained showed the potential of yeasts for application in the removal of hydrophobic compounds. Depending the strain and substrate used the adhesion ability of yeast cells and the production of surfactants and emulsifiers can take place simultaneously, thus increasing the efficiency of bioremediation treatment of petroleum pollution. The application of crude biosurfactants separated from the yeast cells was also demonstrated by tests of removal of petroleum and the derivate motor oil adsorbed in sand samples. Biosurfactants produced in low-cost medium were able to remove 90% of the hydrophobic contaminants.     

Complex Epistasis for Dobzhansky–Muller Hybrid Incompatibility in Solanum

We examined the prevalence of interactions between pairs of short chromosomal regions from one species (Solanum habrochaites) co-introgressed into a heterospecific genetic background (Solanum lycopersicum). Of 105 double introgression line (DIL) families generated from a complete diallele combination of 15 chromosomal segments, 39 (~38%) showed evidence for complex epistasis in the form of genotypic and/or allelic marker transmission distortion in DIL F₂ populations.     

Impact of steroid hormone signals on Drosophila cell cycle during development

Metamorphosis of Drosophila involves proliferation, differentiation and death of larval tissues in order to form the adult fly. The major steroid hormone implicated in the larval-pupal transition and adult tissue modelling is ecdysone. Previous reviews have draw together studies connecting ecdysone signaling to the processes of apoptosis and differentiation. Here we discuss those reports connecting the ecdysone pulse to developmentally regulated cell cycle progression.     

Muscle-associated triglyceride measured by computed tomography and magnetic resonance spectroscopy

Objective: Muscle triglyceride can be assessed in vivo using computed tomography (CT) and ¹H magnetic resonance spectroscopy (MRS), two techniques that are based on entirely different biophysical principles. Little is known, however, about the cross‐correlation between these techniques and their test—retest reliability. Research Methods and Procedures: We compared mean muscle attenuation (MA) in soleus and tibialis anterior (TA) muscles measured by CT with intra‐ and extramyocellular lipids (IMCL and EMCL, respectively) measured by MRS in 51 volunteers (26 to 72 years of age, BMI = 25.5 to 39.3 kg/m²). MA of midthighs was also measured in a subset (n = 19). Test—retest measurements were performed by CT (n = 6) and MRS (n = 10) in separate sets of volunteers. Results: MA of soleus was significantly associated with IMCL (r = ?0.64) and EMCL, which by multiple regression analysis was explained mostly by IMCL (p < 0.001) rather than EMCL (β = ?0.010, p = 0.94). Muscle triglyc‐eride was lower in TA than in soleus, and MA of TA was significantly correlated with EMCL (r = ?0.40) but not IMCL (r = ?0.16). By CT, MA of midthighs was correlated with MA in soleus (r = 0.40, p = 0.07) and whole calf (r = 0.62, p < 0.05). Finally, both MA and IMCL were highly reliable in soleus (coefficient of variation = <2% and 6.7%, respectively) and less reliable in TA (4% and 10%, respectively). Discussion: These results support the use of both CT and MRS as reliable methods for assessing skeletal muscle lipid.     

Scorpionfish rapidly change colour in response to their background

Urban areas are increasing worldwide, which poses threats to animal wildlife. However, in certain cases cities can provide refuges for endangered animals. The European green toad (Bufotes viridis) is one of such examples, which is known from cities throughout their distribution. In contrast, considerable areas of their former (primary) habitats have been degraded. The primary habitats of this species include steppes and wild river floodplains, both characterized by dynamic changes and the presence of open areas. We used available green toad observation data (2007–2020) to model the effects of land-use types on occurrence probability in the city of Vienna. Forest and densely populated areas were highly significantly negatively associated with green toad presence, while transformation/construction site areas showed a strong positive effect. Such occurrence pattern might be characteristic for early succession species, which depend on stochastic environmental disturbances (e.g., droughts and floods) in their primary habitats. We argue that urban landscape planning should appreciate the potential ecological value of open land in cities which is either in a transition phase or a permanent ‘wasteland’. Ecological managing of such landscape could vastly increase urban biodiversity.