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Developing N use efficient potato varieties requires exploring the genetic basis of nitrogen use efficiency (NUE) and associated agronomic and physiological traits. In order to identify QTLs for NUE and NUE-related traits, and to determine the relationships between the traits and QTLs in potato, a diploid potato mapping population (CxE) was evaluated in the field in Ethiopia under low and high N fertilizer levels. QTL detection was performed using interval mapping and multiple QTL mapping (MQM). A total of 52 putative QTLs were identified for ten traits, of which 28 QTLs were detected under low N availability while the remaining 24 QTLs were detected under high N conditions. Several QTLs were location and N level specific, suggesting the presence of QTL x environment interaction. A region on linkage group V (21-38 cM) accumulated the largest number of QTLs. This region coincides with the earliness locus encoded by the CDF1 gene, suggesting that earliness has a profound influence on NUE. A putative second QTL region on linkage group V located 20 cM from the earliness locus (38-56 cM) and a region on linkage group IV (60-72 cM) might be useful other regions to focus on, for NUE improvement in potato. To verify the stability of the identified QTLs and to use these for the detection of possible candidate genes, further multi-environment trials with larger population size may be required.

Thyroid hormone increases the Ca2+-ATPase activity of the sarcoplasmic reticulum (SR) in skeletal muscle, thereby increasing the energy-turnover associated with Ca2+-cycling during contraction and rest. The fast-muscle isoform of the Ca2+-ATPase (SERCA1) and the slow-muscle isoform (SERCA2a), are encoded by two genes that are transcriptionally regulated by T3. The SERCA1 isoform can be expressed to considerably higher levels than the SERCA2a isoform. The stimulation of transcription of the SERCA1 gene by T3 is mediated by two thyroid hormone response elements, located in the promoter of this gene. The intracellular [Ca2+] can modulate the effect of T3. The increase in SR Ca2+-ATPase activity seen when T3-levels rise above normal, results from the induction of SERCA1 expression in slow muscle fibers. Concomitant high levels of Ca2+-ATPase activity are associated with down-regulation of SERCA2a expression in these fibers. The observed T3-dependent increase in SERCA1 expression and associated Ca2+-ATPase activity will increase the overall metabolic rate of the organism significantly under normal conditions, because of the high average level of contractile activity of slow fibers. Given the rise in serum T3-levels during prolonged cold exposure, these data suggest that fiber-specific stimulation of SERCA1 expression contributes to the thermogenic response in non-shivering thermogenesis. This mechanism may be particularly relevant in larger mammals, which have a relatively high percentage of slow fibers in skeletal muscle, and which need to rely on tissues other than brown fat for the generation of extra heat.

Thyroid hormone increases the Ca2+-ATPase activity of the sarcoplasmic reticulum (SR) in skeletal muscle, thereby increasing the energy-turnover associated with Ca2+-cycling during contraction and rest. The fast-muscle isoform of the Ca2+-ATPase (SERCA1) and the slow-muscle isoform (SERCA2a), are encoded by two genes that are transcriptionally regulated by T3. The SERCA1 isoform can be expressed to considerably higher levels than the SERCA2a isoform. The stimulation of transcription of the SERCA1 gene by T3is mediated by two thyroid hormone response elements, located in the promoter of this gene. The intracellular [Ca2+] can modulate the effect of T3. The increase in SR Ca2+-ATPase activity seen when T3-levels rise above normal, results from the induction of SERCA1 expression in slow muscle fibers. Concomitant high levels of Ca2+-ATPase activity are associated with down-regulation of SERCA2a expression in these fibers. The observed T3-dependent increase in SERCA1 expression and associated Ca2+-ATPase activity will increase the overall metabolic rate of the organism significantly under normal conditions, because of the high average level of contractile activity of slow fibers. Given the rise in serum T3-levels during prolonged cold exposure, these data suggest that fiber-specific stimulation of SERCA1 expression contributes to the thermogenic response in non-shivering thermogenesis. This mechanism may be particularly relevant in larger mammals, which have a relatively high percentage of slow fibers in skeletal muscle, and which need to rely on tissues other than brown fat for the generation of extra heat.

High-frequency stimulation of the internal pallidum is an effective surgical approach for patients with advanced Parkinson's disease suffering from motor fluctuations and L-dopa induced dyskinesia. To study the acute effects of internal pallidum stimulation, changes in cerebral blood flow were measured by means of a single-day split-dose protocol using 99Tcm-ECD SPET. Nine patients with advanced Parkinson's disease and with a clinical picture predominated by tremor and drug-induced dyskinesia, were imaged before and immediately after electrostimulation. Brain perfusion data were mirrored to the same electrode side (five left and four right implants), co-registered and analysed statistically on a voxel-by-voxel basis (Statistical Parametric Mapping) and by an automated volume-of-interest approach. Acute stimulation of the internal pallidum induced a significantly decreased perfusion in the ipsilateral thalamus and striatum, as well as in the right parietal cortex. For the subgroup of seven patients with effective motor score improvements, a significant correlation between thalamic and striatal perfusion changes and UPDRS III motor score was present (P0.04). These results suggest that effective stimulation of the internal globus pallidus may produce symptom relief through decreased activity in pallido-thalamo-cortical circuits.

Administration of extra branched chain amino acids (BCAA) has been associated with a nitrogen sparing effect in septic and traumatized patients. Whether nitrogen sparing is associated with decreased morbidity and mortality rates is unknown. We therefore undertook a prospective, randomized, double blind trial investigating the effects of BCAA enrichment of a total parenteral nutrition (TPN) regimen on nitrogen balance, 3-methylhistidine excretion, morbidity as evidenced by disturbances in organ function, severity of sepsis and mortality. One hundred and one patients entered the study; 52 received a standard TPN solution and 49 a BCAA-enriched solution. Both groups received 30 kcal kg−1body-weight, 15 per cent fat calories and 0·17g nitrogen kg−1body-weight. In the BCAA-enriched group, patients received 0·56 g BCAAkg−1body-weight (50·2 per cent BCAA). Standard group patients received 0·18g BCAA kg−1body-weight (15·6 per cent BCAA). Nitrogen balances and 3-methylhistidine excretion were not significantly different between groups. Although morbidity scores tended to decrease during the study, no difference was observed between groups. Mortality (early or late), sepsis or stress-related, did not differ significantly between groups. We were not able to confirm the reported beneficial effects of BCAA-enriched TPN solutions for use in septic and traumatized patients.

Relaxation of skeletal muscle requires the re-uptake of Ca2+, which is mediated by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Thyroid hormone (T3) stimulates the expression of the SERCA1 isoform, which is essential for fast skeletal muscle fiber phenotype. We have cloned and studied the first 962 base pairs of the 5'-flanking region of the rat SERCA1 gene. This sequence was tested for T3-regulated expression in transient transfection experiments using COS7 cells and for binding of thyroid hormone receptor (TR) alpha in mobility shift assays. A construct of the 5'-flanking region and a reporter gene was unresponsive to T3 in the absence of co-transfected thyroid hormone receptor. In the presence of TRalpha, a T3 induction ratio of almost 4.0 was found, and this induction ratio was doubled with co-transfection of an RXR expression plasmid. Analysis of progressive 5'-deletion fragments of the sequence indicated multiple regions involved in T3 responsiveness. Three regions, R1, R2, and R3, were identified that bound TR complexes in mobility shift assays and conferred T3 responsiveness to a heterologous promoter. The most potent of these thyroid hormone response elements, R3, increased the 2-fold background T3 stimulation of the thymidine kinase promoter to nearly 6-fold. Detailed analysis of this element showed that four TR-binding half-sites, comprising two independent thyroid hormone response elements, interact cooperatively to give the maximal T3 response. T3 regulation of SERCA1 expression is mediated by a complex thyroid hormone response element that may serve to provide a greater range of response in interaction with nuclear receptor partners or cell-specific transcription factors.

Relaxation of skeletal muscle requires the re-uptake of Ca2+, which is mediated by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Thyroid hormone (T3) stimulates the expression of the SERCA1 isoform, which is essential for fast skeletal muscle fiber phenotype. We have cloned and studied the first 962 base pairs of the 5′-flanking region of the rat SERCA1 gene. This sequence was tested for T3-regulated expression in transient transfection experiments using COS7 cells and for binding of thyroid hormone receptor (TR) α in mobility shift assays. A construct of the 5′-flanking region and a reporter gene was unresponsive to T3in the absence of co-transfected thyroid hormone receptor. In the presence of TRα, a T3induction ratio of almost 4.0 was found, and this induction ratio was doubled with co-transfection of an RXR expression plasmid. Analysis of progressive 5′-deletion fragments of the sequence indicated multiple regions involved in T3responsiveness. Three regions, R1, R2, and R3, were identified that bound TR complexes in mobility shift assays and conferred T3responsiveness to a heterologous promoter. The most potent of these thyroid hormone response elements, R3, increased the 2-fold background T3stimulation of the thymidine kinase promoter to nearly 6-fold. Detailed analysis of this element showed that four TR-binding half-sites, comprising two independent thyroid hormone response elements, interact cooperatively to give the maximal T3response. T3regulation of SERCA1 expression is mediated by a complex thyroid hormone response element that may serve to provide a greater range of response in interaction with nuclear receptor partners or cell-specific transcription factors.

The in vitro production of interleukin-1beta (IL-1beta), IL-6, and the IL-1 receptor antagonist (IL-1ra) in whole blood upon stimulation with different bacterial strains was measured to study the possible relationship between disease severity and the cytokine-inducing capacities of these strains. Escherichia coli, Neisseria meningitidis, Neisseria gonorrhoeae, Bacteroides fragilis, Capnocytophaga canimorsus, Staphylococcus aureus, Enterococcus faecalis, Streptococcus pneumoniae, and Streptococcus pyogenes induced the cytokines IL-1beta, IL-6, and IL-1ra. Gram-negative bacteria induced significantly higher levels of proinflammatory cytokine production than gram-positive bacteria. These differences were less pronounced for the anti-inflammatory cytokine IL-1ra. In addition, blood was stimulated with E. coli killed by different antibiotics to study the effect of the antibiotics on the cytokine-inducing capacity of the bacterial culture. E. coli treated with cefuroxime and gentamicin induced higher levels of IL-1beta and IL-6 production but levels of IL-1ra production similar to that of heat-killed E. coli. In contrast, ciprofloxacin- and imipenem-cilastatin-mediated killing showed a decreased or similar level of induction of cytokine production as compared to that by heat-killed E. coli; polymyxin B decreased the level of production of the cytokines.

In this report we investigated local regulatory mechanisms in graft rejection and their response to local immunosuppressive therapy. For this purpose local immunosuppression was induced in rat kidney allografts by intrarenal infusion of prednisolone. Intrarenal drug delivery resulted in high drug levels within the graft and low systemic drug levels. Systemic drug levels were by themselves not sufficiently immunosuppressive to induce graft survival, and local prednisolone levels within the graft proved to be responsible for prolongation of graft survival. During intrarenal drug delivery, systemic responsiveness to the renal allograft proved normal, since intrarenally treated grafts were infiltrated by MHC class II-positive host cells and, except for a somewhat lower percentage of macrophages, cellular infiltration in intrarenal treated grafts was comparable to untreated grafts. However, T cells and macrophages present in intrarenally treated grafts were not able to destroy the grafted tissue. Local immunosuppressive therapy resulted in inhibition of IL-2-R expression, absence of IFN-gamma, and prevention of MHC class II induction on grafted tissue. These observations strongly indicate the presence of local regulatory mechanisms in graft rejection. The experimental model described can be used for further analysis of these intragraft events. Moreover, the results demonstrate that local immunosuppressive therapy can contribute to effective inhibition of cellular immune response in graft rejection.

Changes in the expression of class II antigens of the major histocompatibility complex (MHC) have an integral role in the regulation of immune responses, and are brought about in vitro by soluble mediators1–4. However, the mechanism that underlies in vivo expression of MHC class II antigens in, for example, endothelial cells in the absence of immunological stimulation has not been studied. We demonstrate here that expression of MHC class II antigens is not a constitutive property of endothelial cells, for MHC class II antigen-positive endothelial cells do not express these antigens during treatment with the immunosuppressive agent cyclosporin A. In vivo MHC class II antigen expression by canine endothelial cells is therefore dependent on factors, probably the lymphokine γ-interferem produced by the immune system, whose secretion is inhibited by cyclosporin A.

This corrects the article DOI: 10.1038/nature21370