Structure and specificity of a class II MHC alloreactive gamma delta T cell receptor heterodimer

Two distinct CD3-associated T cell receptors (TCR alpha beta and TCR gamma delta) are expressed in a mutually exclusive fashion on separate subsets of T lymphocytes. While the specificity of the TCR alpha beta repertoire for major histocompatibility complex (MHC) antigens is well established, the diversity of expressed gamma delta receptors and the ligands they recognize are less well understood. An alloreactive CD3+CD4-CD8- T cell line specific for murine class II MHC (Ia) antigens encoded in the I-E subregion of the H-2 gene complex was identified, and the primary structure of its gamma delta receptor heterodimer was characterized. In contrast to a TCR alpha beta-expressing alloreactive T cell line selected for similar specificity, the TCR gamma delta line displayed broad cross-reactivity for multiple distinct I-E-encoded allogeneic Ia molecules.     

A model of human acute lymphoblastic leukemia in immune-deficient SCID mice

A human acute lymphoblastic leukemia (ALL) cell line that was transplanted into immune-deficient SCID mice proliferated in the hematopoietic tissues, invaded various organs, and led to the death of the mice. The distribution of leukemic cells in SCID mice was similar to the course of the disease in children. A-1 cells marked with a retrovirus vector showed clonal evolution after the transplant. SCID mice that were injected with bone marrow from three patients with non-T ALL had leukemic cells in their bone marrow and spleen. This in vivo model of human leukemia is an approach to understanding leukemic growth and progression and is a novel system for testing new treatment strategies.     

Essential fatty acid deficiency in freshwater fish: the effects of linoleic, α-linolenic, γ-linolenic and stearidonic acids on the metabolism of [1-14C]18:3n-3 in a carp cell culture model

The desaturation of [1-¹⁴C]18:3n-3 to 20:5n-3 and 22:6n-3 is enhanced in an essential fatty acid deficient cell line (EPC-EFAD) in comparison with the parent cell line (EPC) from carp. In the present study, the effects of competing, unlabeled C₁₈ polyunsaturated fatty acids (PUFA), linoleic (18:2n-6), -linolenic (18:3n-3), -linolenic (18:3n-6) and stearidonic (18:4n-3) acids, on the metabolism of [1-¹⁴C]18:3n-3 were investigated in EPC-EFAD cells in comparison with EPC cells. The incorporation of [1-¹⁴C]18:3n-3 in both cell lines was significantly reduced by competing C₁₈ PUFA, with the rank order being 18:4n-3>18:3n-3 = 18:2n-6>18:3n-6. In the absence of competing PUFA, radioactivity from [1-¹⁴C]18:3n-3 in EPC cells was predominantly recovered in phosphatidylethanolamine followed by phosphatidylcholine. This pattern was unaffected by competing n-6PUFA, but n-3PUFA reversed this pattern as did essential fatty acid deficiency in the presence of all competing PUFA. The altered lipid class distribution was most pronounced in cells supplemented with 18:4n-3. Competing C₁₈ PUFA significantly decreased the proportions of radioactivity recovered in 22:6n-3, pentaene and tetraene products, with the proportions of radioactivity recovered in 18:3n-3 and 20:3n-3 increased, in both cell lines. However, the inhibitory effect of competing C₁₈ PUFA on the desaturation of [1-¹⁴C]18:3n-3 was significantly greater in EPC-EFAD cells. The magnitude of the inhibitory effects of C₁₈ PUFA on [1-¹⁴C]18:3n-3 desaturation was dependent upon the specific fatty acid with the rank order being 18:4n-3>18:3n-3>18:2n-6, with 18:3n-6 having little inhibitory effect on the metabolism of [1-¹⁴C]18:3n-3 in EPC cells. The differential effects of the C₁₈ PUFA on [1-¹⁴C]18:3n-3 metabolism were consistent with mass competition in combination with increased desaturation activity in EPC-EFAD cells and the known substrate fatty acid specificities of desaturase enzymes. However, the mechanism underpinning the greater efficacy with which the unlabeled C₁₈PUFA competed with [1-¹⁴C]18:3n-3 in the desaturation pathway in EPC-EFAD cells was unclear.     

The role of the wood mechanical industry in the Swedish forest industry cluster

The forest and forest products form one of the most important basis for the transfer to a bio-based economy in Sweden. About 75% of the area covered by forest in Sweden is used industrially to produce raw material for the wood-refining industries. Every year, this cluster uses 75 million m³ of roundwood and has an export value of €12 billion. This review paper is devoted to the wood mechanical industry, i.e. the industry which turns the forest into sawn timber, packaging, construction wood, furniture and interior fittings. The sawmills consume about half of the volume of softwood which is felled, and about two-thirds of the sawn timber go to export without any further refining within the country. Nevertheless, in spite of the relatively low degree of refinement in the sawmill and the fact that the sawmills in general over time have a very low profitability, they are responsible for 70–80% of the forest owners' profits on the sale of timber. An increased upgrading of the sawn timber within the country is desirable from a national economic viewpoint – increased employment opportunities, increased export income, etc. It should then in the first place be for products with a higher added value, such as furniture and fittings. Today, the refinement value is 15–20 times higher for products from joinery and furniture industries compared to that of the sawn timber, and the added value of the wood within the building industry is only about 1.5 times.     

Three-dimensional finite element modelling of heat transfer for linear friction welding of Scots pine

Finite element numerical analyses were performed to determine three-dimensional heat flux generated by friction to wood pieces during linear friction welding. The objective was to develop a computational model to explain the thermal behaviour of welded wood material rather than experimental methods, which are usually expensive and time consuming. This model serves as a prediction tool for welding parameters, leading to optimal thermo-mechanical performance of welded joints. The energy produced by the friction welding of small wood specimens of Scots pine (Pinus sylvestris L.) was determined by thermocouples and used as input data in the model. The model is based on anisotropic elasticity and the thermal properties were modelled as isotropic. This numerical simulation gave information on the distribution of the temperature in the welding interface during the entire welding process. A good agreement between the simulation and experimental results showed the appropriateness of the model for planning welded wood manufacture and prediction of thermal behaviour of wood during other mechanically induced vibration processes. The specimens presented in this model required a heat flux of 11 kW/m² to achieve a satisfactory welding joint.     

High feeding intensity increases the severity of fatty liver in the American mink (Neovison vison) with potential ameliorating role for long-chain n-3 polyunsaturated fatty acids

Background

Rapid body fat mobilization, obesity, and an inadequate supply of n-3 polyunsaturated fatty acids (PUFA) have been suggested to play roles in the etiology of fatty liver in the American mink (Neovison vison). This study examined the effects of feeding intensity and dietary fat source on fatty liver induced by fasting. In a multi-factorial design, 3 different fat sources (herring oil, rich in n-3 PUFA, soya oil, rich in n-6 PUFA, and canola oil, rich in n-9 monounsaturated fatty acids) were fed to mink at a low and high feeding intensity for 10 weeks, followed by an overnight or a 5-day fasting treatment to induce fatty liver.

Results

Fasting led to the development of fatty liver with increased severity in the mink fed at the high feeding intensity. The herring oil diet, high in long-chain n-3 PUFA, was found to decrease the severity of fatty liver in the mink at the high feeding intensity.

Conclusion

Preventing excessive weight gain and increasing dietary intake of n-3 long-chain PUFA may help prevent excessive lipid accumulation during prolonged periods of fasting or inappetence by promoting hepatic fatty acid oxidation.     

Enzyme activities in soil treated with sulfite- or sulfate-based flue gas desulfurization products

A study was conducted to examine the impact of synthetic calcium sulfite (CaSO₃?·?0.5H₂O) and calcium sulfate (CaSO₄?·?2H₂O, i.e., gypsum) from flue gas desulfurization (FGD) on soil enzyme activities, used as soil quality indicators, following land application. We used application rates of 0, 1.12 Mg ha^?1 of FGD-CaSO₃ (CaS-1.12T), 3.36 Mg ha^?1 of FGD-CaSO₃ (CaS-3.36T), and 1.12 Mg ha^?1 of FGD-gypsum (Gyp-1.12T). The field experiments were conducted on a silt loam soil with 1.6 % total C and a pH of 6.5. No crop was grown during the experiment. The concentration of water soluble SO₄ ^2?-S and the associated electrical conductivity (EC) significantly increased during the first 2 weeks following gypsum application but decreased later on (2–4 weeks) due to leaching. There was no significant difference between the Gyp-1.12T and CaS-1.12T treatment after approximately 2 weeks indicating all of the sulfite in the CaS-1.12T treatment was completely oxidized to sulfate. In contrast, the sulfite treated with highest application rate (CaS-3.36T) was not completely oxidized within the 12-week experimental period. Application of FGD-CaSO₃ and FGD-CaSO₄ did not negatively affect C and N mineralization because β-glucosidase and β-d-glucosaminidase activities did not show any negative change compared with the control. Arylsulfatase activity of the CaS-1.12T treatment markedly declined compared with Gyp-1.12T and control, but then increased after 2 weeks. The arylsulfatase activity reduction, however, persisted for the duration of the experiment in the CaS-3.36T treatment. These activity changes were similar to the observed oxidation pattern of sulfite to sulfate, which indicated that arylsulfatase activity could be used as an indicator for the extent of sulfite oxidation in soil.     

LONG‐TERM LAND USE INFLUENCES SOIL MICROBIAL BIOMASS P AND S,PHOSPHATASE AND ARYLSULFATASE ACTIVITIES,AND S MINERALIZATION IN A BRAZILIAN OXISOL

Land use choices differentially affect soil physical and biological properties. Tillage choices in particular affect soil erosion, the retention of soil organic matter, and the biological activity that organic matter supports. The present study evaluated the consequences of different cropping and tillage systems (undisturbed forest, coffee plantation, conventional, and no‐tillage row cropping) for soil microbial indicators and sulfur mineralization after 24 years of cropping on an Oxisol (Typic Haplorthox) in an experimental area at Londrina, Brazil. Soil samples were taken at 0–5, 5–10, and 10–20 cm depths and evaluated for microbial biomass P and S, S mineralization, and phosphatase and arylsulfatase activities. Land use affected microbial biomass P and S, and enzyme activity at all depths studied. The cultivated sites had lower values of microbial activity than the undisturbed forested site. Although the coffee site was not tilled and had high organic carbon content, there was low microbial activity, probably due to higher soil acidity and Al content. The estimates of pool stock for microbial P and annual P flux through the soil microbial biomass suggest that these pools are large enough to significantly affect plant nutrient availability. The greater microbial biomass and activity under forested and no‐tillage sites may be attributed, at least partially, to higher organic matter content. The soil microbial variables examined proved to be strong indicators of soil sustainability. Copyright © 2013 John Wiley & Sons, Ltd.