Somatic hybrids between the cultivated potato Solanum tuberosum L. and the 1EBN wild species Solanum pinnatisectum Dun.: morphological and molecular characterization

Interspecific somatic hybrids between the 1EBN-wild species Solanum pinnatisectum (S. pnt) and four different diploid breeding lines of Solanum tuberosum (S. tbr) were produced by electrofusion. S. pnt exhibits resistance to Phytophthora infestans and Erwinia blackleg. Somatic hybrids were identified by RFLP analysis using the oligonucleotide (GATA)₄ as a probe. In three of four combinations all regenerates obtained were somatic hybrids. All 86 somatic hybrids between the breeding line H256/1 and S. pnt were analyzed in detail with respect to morphological and molecular characters; 50% of the somatic hybrids showed normal intermediate leaf morphology. Tubers of somatic hybrid plants grown in the greenhouse as well as in the field were evenly shaped and remarkably similar to those of the S. tbr breeding line. Analysis of relative DNA content by flow cytometry revealed that 75% of the somatic hybrids were tetraploid, some were hypotetraploid and others polyploid or mixoploid. Slotblot and RFLP analyses were carried out using repetitive and some single-copy DNA probes. The genome portion of the S. tbr breeding line was determined by slot-blot analysis using the species-specific repetitive probe pSA287. Obviously, most somatic hybrids contain the complete genomes of both fusion partners. In some of the somatic hybrids, a significantly lower intensity of the S. pnt-specific hybridization signal indicated a certain degree of asymmetry.Dedicated to Prof. Melchers on the occasion of his 90th birthday     

Asymmetric fusion between wild and cultivated species of potato (Solanum spp.) –detection of asymmetric hybrids and genome elimination

 The objective of this study was to evaluate the suitability of different techniques for a simple and rapid identification of asymmetric hybrids, without the use of selection markers and independent of the fusion partners used. Additionally, the degree of donor DNA elimination was determined. Among 473 viable plants obtained from asymmetric fusion experiments between three di-haploid breeding lines of potato (Solanum tuberosum) and diploid wild species (S. bulbocastanum, S. circaeifolium; X-ray treatment of the wild species) the most promising ones were investigated with three different methods: flow cytometry, RFLP analysis with an oligonucleotide probe (GATA)₄, and with single-copy probes. Flow cytometry, which combines a high screening capacity with detailed information about the DNA content and allows a distinction between asymmetric hybrids and chimeras, detected 31 hypo-tetraploid and 42 hypo-hexaploid regenerates among 224 plants. With the oligonucleotide probe (GATA)₄ only a few asymmetric hybrids were detected among all regenerates. More than 50% of these asymmetric regenerates were chimeras. Concerning the degree of DNA elimination, the results obtained by RFLP analysis with 17 single-copy probes were correlated with the results obtained by flow cytometry. The maximum DNA elimination of the donor genome was 52%. As a trend, an irradiation dosage of 210 Gy caused a higher DNA elimination in the wild species than a dosage of 70 Gy. No calli were obtained after irradiation of the wild species with 420 Gy. Received : 6 December 1996/Accepted: 24 January 1997     

Chromosome numbers in North and Central American Compositae

Chromosome numbers are reported for 364 collections representing 70 species and varieties in 16 genera. Of these, 35 species and varieties have not had counts published previously. Counts of 26 collections in 14 species differ from all previously published counts for the same species. One new combination,Stevia anadenotricha, and one new variety,Stevia subpubescens var.intermedia, are published.     

NIK prevents the development of hypereosinophilic syndrome-like disease in mice independent of IKKα activation

Immune cell-mediated tissue injury is a common feature of different inflammatory diseases, yet the pathogenetic mechanisms and cell types involved vary significantly. Hypereosinophilic syndrome (HES) represents a group of inflammatory diseases that is characterized by increased numbers of pathogenic eosinophilic granulocytes in the peripheral blood and diverse organs. On the basis of clinical and laboratory findings, various forms of HES have been defined, yet the molecular mechanism and potential signaling pathways that drive eosinophil expansion remain largely unknown. In this study, we show that mice deficient of the serine/threonine-specific protein kinase NF-κB-inducing kinase (NIK) develop a HES-like disease, reflected by progressive blood and tissue eosinophilia, tissue injury, and premature death at around 25-30 wk of age. Similar to the lymphocytic form of HES, CD4(+) T cells from NIK-deficient mice express increased levels of Th2-associated cytokines, and eosinophilia and survival of NIK-deficient mice could be prevented completely by genetic ablation of CD4(+) T cells. Experiments based on bone marrow chimeric mice, however, demonstrated that inflammation in NIK-deficient mice depended on radiation-resistant tissues, implicating that NIK-deficient immune cells mediate inflammation in a nonautonomous manner. Surprisingly, disease development was independent of NIK's known function as an IκB kinase α (IKKα) kinase, because mice carrying a mutation in the activation loop of IKKα, which is phosphorylated by NIK, did not develop inflammatory disease. Our data show that NIK activity in nonhematopoietic cells controls Th2 cell development and prevents eosinophil-driven inflammatory disease, most likely using a signaling pathway that operates independent of the known NIK substrate IKKα.     

Variability in the Efficacy of Psychopharmaceuticals: Contributions from Pharmacogenomics, Ethnopsychopharmacology, and Psychological and Psychiatric Anthropologies

Psychological and psychiatric anthropology have long questioned the universality of psychiatric diagnoses, bringing to light the fluidity of mental disorder, and recognizing that the experience and expression of psychopathology is influenced by complex and interacting genetic, environmental, and cultural factors. The majority of our discussions, however, have remained centered around the role of culture in shaping mental illness: drawing attention to subjective experiences of mental illness and culturally patterned modes of symptom presentation, and interrogating the cogency of universal diagnostic rubrics. Psychological and psychiatric anthropology have yet to robustly engage the broadly assumed universal validity of psychiatric medications and the ways in which they are prescribed and experienced. This article provides an introduction into the fields of pharmacogenomics and ethnopsychopharmacology, areas of inquiry seeking to understand the ways in which genetic variability occurring between, and within, large population groups influences individual ability to metabolize psychotropic medications. This piece further addresses the complex issue of psychopharmaceutical efficacy, stressing the ways in which, just as with psychopathology, medications and their outcomes are likewise influenced by the complex interactions of genes, environment, and culture. Lastly, ways in which anthropology can and should engage with the growing fields of pharmacogenomics and ethnopsychopharmacology are suggested.     

Role of the Transmembrane Potential in the Membrane Proton Leak

The molecular mechanism responsible for the regulation of the mitochondrial membrane proton conductance (G) is not clearly understood. This study investigates the role of the transmembrane potential (ΔΨ_m) using planar membranes, reconstituted with purified uncoupling proteins (UCP1 and UCP2) and/or unsaturated FA. We show that high ΔΨ_m (similar to ΔΨ_m in mitochondrial State IV) significantly activates the protonophoric function of UCPs in the presence of FA. The proton conductance increases nonlinearly with ΔΨ_m. The application of ΔΨ_m up to 220 mV leads to the overriding of the protein inhibition at a constant ATP concentration. Both, the exposure of FA-containing bilayers to high ΔΨ_m and the increase of FA membrane concentration bring about the significant exponential G_m increase, implying the contribution of FA in proton leak. Quantitative analysis of the energy barrier for the transport of FA anions in the presence and absence of protein suggests that FA⁻ remain exposed to membrane lipids while crossing the UCP-containing membrane. We believe this study shows that UCPs and FA decrease ΔΨ_m more effectively if it is sufficiently high. Thus, the tight regulation of proton conductance and/or FA concentration by ΔΨ_m may be key in mitochondrial respiration and metabolism.     

Pantothenate Kinase 1 Is Required to Support the Metabolic Transition from the Fed to the Fasted State

Coenzyme A (CoA) biosynthesis is regulated by the pantothenate kinases (PanK), of which there are four active isoforms. The PanK1 isoform is selectively expressed in liver and accounted for 40% of the total PanK activity in this organ. CoA synthesis was limited using a Pank1 ^−/− knockout mouse model to determine whether the regulation of CoA levels was critical to liver function. The elimination of PanK1 reduced hepatic CoA levels, and fasting triggered a substantial increase in total hepatic CoA in both Pank1 ^−/− and wild-type mice. The increase in hepatic CoA during fasting was blunted in the Pank1 ^−/− mouse, and resulted in reduced fatty acid oxidation as evidenced by abnormally high accumulation of long-chain acyl-CoAs, acyl-carnitines, and triglycerides in the form of lipid droplets. The Pank1 ^−/− mice became hypoglycemic during a fast due to impaired gluconeogenesis, although ketogenesis was normal. These data illustrate the importance of PanK1 and elevated liver CoA levels during fasting to support the metabolic transition from glucose utilization and fatty acid synthesis to gluconeogenesis and fatty acid oxidation. The findings also suggest that PanK1 may be a suitable target for therapeutic intervention in metabolic disorders that feature hyperglycemia and hypertriglyceridemia.     

Fatal hemorrhagic diathesis associated with mild factor IX deficiency in pl/J mice

Surgical implantation of devices into the abdomen of PL/J mice was associated with fatal hemorrhage at 9 to 11 d after surgery. Coagulation profiles were evaluated to determine the underlying cause of this effect. The mean activated partial thromboplastin time (aPTT) of untreated PL/J mice was significantly higher than that of BALB/cByJ and C57BL/6J strains. The addition of human plasmas deficient in factors VIII, XI, or XII, prekallikrein, or high molecular-weight kininogen corrected the elevated aPTT of PL/J mice, but correction did not occur when factor IX-deficient human plasma was added. When compared to an assigned factor IX activity of 100% for pooled plasma from BALB/cByJ mice, C57BL/6J and PL/J mice revealed percent activities of 67% and 16%, respectively. PL/J mice could represent a new model for the study of pathogenesis and therapy of mild factor IX deficiency that is expressed and becomes clinically apparent secondary to major surgery.