Hybridization between Taeniatherum caput-medusae and Triticum aestívum (Poaceae)

Hybrid plants were obtained in an intergeneric cross between Taenìatherum caputmedusae (2n = 2x = 14) and Triticum aestívum (2n = 6x = 42). The chromosome number was as expected 2n = 28. Morphologically the offspring looked like Triticum aestívum . Analysis of meiotic metaphase I showed an unexpected high number of bi- and trivalents which is ascribed to homoeologous pairing of chromosomes from T. aestivum . It is concluded that the genome of Taeniatherum has effects on the pairing regulation system present in T. aestívum .     

Expression patterns and adaptive functional diversity of vertebrate myoglobins

Recent years have witnessed a new round of research on one of the most studied proteins - myoglobin (Mb), the oxygen (O₂) carrier of skeletal and heart muscle. Two major discoveries have stimulated research in this field: 1) that Mb has additional protecting functions, such as the regulation of in vivo levels of the signaling molecule nitric oxide (NO) by scavenging and generating NO during normoxia and hypoxia, respectively; and 2) that Mb in vertebrates (particularly fish) is expressed as tissue-specific isoforms in other tissues than heart and skeletal muscle, such as vessel endothelium, liver and brain, as found in cyprinid fish. Furthermore, Mb has also been found to protect against oxidative stress after hypoxia and reoxygenation and to undergo allosteric, O₂-linked S-nitrosation, as in rainbow trout. Overall, the emerging evidence, particularly from fish species, indicates that Mb fulfills a broader array of physiological functions in a wider range of different tissues than hitherto appreciated. This new knowledge helps to better understand how variations in Mb structure and function may correlate with differences in animals' lifestyles and hypoxia-tolerance. This review integrates old and new results on Mb expression patterns and functional properties amongst vertebrates and discusses how these may relate to adaptive variations in different species. This article is part of a special issue entitled: Oxygen Binding and Sensing Proteins.     

Intake of Farmed Atlantic Salmon Fed Soybean Oil Increases Insulin Resistance and Hepatic Lipid Accumulation in Mice

Background

To ensure sustainable aquaculture, fish derived raw materials are replaced by vegetable ingredients. Fatty acid composition and contaminant status of farmed Atlantic salmon (Salmo salar L.) are affected by the use of plant ingredients and a spillover effect on consumers is thus expected. Here we aimed to compare the effects of intake of Atlantic salmon fed fish oil (FO) with intake of Atlantic salmon fed a high proportion of vegetable oils (VOs) on development of insulin resistance and obesity in mice.

Methodology/principal findings

Atlantic salmon were fed diets where FO was partly (80%) replaced with three different VOs; rapeseed oil (RO), olive oil (OO) or soy bean oil (SO). Fillets from Atlantic salmon were subsequently used to prepare Western diets (WD) for a mouse feeding trial. Partial replacement of FO with VOs reduced the levels of polychlorinated biphenyls (PCB) and dichloro-diphenyl-tricloroethanes (DDT) with more than 50% in salmon fillets, in WDs containing the fillets, and in white adipose tissue from mice consuming the WDs. Replacement with VOs, SO in particular, lowered the n−3 polyunsaturated fatty acid (PUFA) content and increased n−6 PUFA levels in the salmon fillets, in the prepared WDs, and in red blood cells collected from mice consuming the WDs. Replacing FO with VO did not influence obesity development in the mice, but replacement of FO with RO improved glucose tolerance. Compared with WD-FO fed mice, feeding mice WD-SO containing lower PCB and DDT levels but high levels of linoleic acid (LA), exaggerated insulin resistance and increased accumulation of fat in the liver.

Conclusion/Significance

Replacement of FO with VOs in aqua feed for farmed salmon had markedly different spillover effects on metabolism in mice. Our results suggest that the content of LA in VOs may be a matter of concern that warrants further investigation.     

Dynamic changes in the structure of microbial communities in Baltic Sea coastal seawater microcosms modified by crude oil,shale oil or diesel fuel

The coastal waters of the Baltic Sea are constantly threatened by oil spills, due to the extensive transportation of oil products across the sea. To characterise the hydrocarbon-degrading bacterial community of this marine area, microcosm experiments on diesel fuel, crude oil and shale oil were performed. Analysis of these microcosms, using alkane monooxygenase (alkB) and 16S rRNA marker genes in PCR-DGGE experiments, demonstrated that substrate type and concentration strongly influence species composition and the occurrence of alkB genes in respective oil degrading bacterial communities. Gammaproteobacteria (particularly the genus Pseudomonas) and Alphaproteobacteria were dominant in all microcosms treated with oils. All alkB genes carried by bacterial isolates (40 strains), and 8 of the 11 major DGGE bands from the microcosms, had more than 95% sequence identity with the alkB genes of Pseudomonas fluorescens. However, the closest relatives of the majority of sequences (54 sequences from 79) of the alkB gene library from initially collected seawater DNA were Actinobacteria. alkB gene expression, induced by hexadecane, was recorded in isolated bacterial strains. Thus, complementary culture dependent and independent methods provided a more accurate picture about the complex seawater microbial communities of the Baltic Sea.     

Skeletal muscle bioenergetics: a comparative study of mitochondria isolated from pigeon pectoralis, rat soleus, rat biceps brachii, pig biceps femoris and human quadriceps

The metabolism of mitochondria isolated from five functionally different skeletal muscles is compared. Data for a single ectothermic preparation are also reported. The mitochondria were prepared in yields of 44+/-7% from 50 to 100 mg muscle. The muscle content of mitochondrial protein ranged between 2 and 40 g kg(-1). Twelve specific activities of key enzymes and metabolic systems were determined, 10 of these in functional assays with respiratory measurements. The specific activities of glutamate dehydrogenase, alpha-glycerophosphate dehydrogenase, and exo-NADH oxidase differed considerably among muscle sources. Seven specific activities, including very central reactions, showed low among-muscle variation. The activity of ATP synthesis, for instance, was 1.0-1.3 mmol min(-1) g(-1) mitochondrial protein, 25 degrees C. In vitro data were extrapolated to in vivo conditions of the muscles. The calculated rates of respiration and ATP synthesis were in accordance with reported tissue activities. Pigeon pectoralis mitochondria showed a unique cytochrome spectrum and a respiratory chain activity that might effect simultaneous carbohydrate and fatty acid respiration. In mitochondria from the other muscles, the respiratory chain activity balanced the carbohydrate oxidation capacity. In all muscles, the respiratory capacity exceeds that needed for oxidative phosphorylation. This may secure maximal mitochondrial ATP synthesis during maximal work rates and high cellular [Ca(2+)].