Tomato: a crop species amenable to improvement by cellular and molecular methods

Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

Targeting endothelial and myocardial dysfunction with tetrahydrobiopterin.

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Pathogenetic role of eNOS uncoupling in cardiopulmonary disorders.

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Altered high-energy phosphate metabolism predicts contractile dysfunction and subsequent ventricular remodeling in pressure-overload hypertrophy mice.

To study the role of early energetic abnormalities in the subsequent development of heart failure, we performed serial in vivo combined magnetic resonance imaging (MRI) and (31)P magnetic resonance spectroscopy (MRS) studies in mice that underwent pressure-overload following transverse aorta constriction (TAC). After 3 wk of TAC, a significant increase in left ventricular (LV) mass (74 +/- 4 vs. 140 +/- 26 mg, control vs. TAC, respectively; P < 0.000005), size [end-diastolic volume (EDV): 48 +/- 3 vs. 61 +/- 8 microl; P < 0.005], and contractile dysfunction [ejection fraction (EF): 62 +/- 4 vs. 38 +/- 10%; P < 0.000005] was observed, as well as depressed cardiac energetics (PCr/ATP: 2.0 +/- 0.1 vs. 1.3 +/- 0.4, P < 0.0005) measured by combined MRI/MRS. After an additional 3 wk, LV mass (140 +/- 26 vs. 167 +/- 36 mg; P < 0.01) and cavity size (EDV: 61 +/- 8 vs. 76 +/- 8 microl; P < 0.001) increased further, but there was no additional decline in PCr/ATP or EF. Cardiac PCr/ATP correlated inversely with end-systolic volume and directly with EF at 6 wk but not at 3 wk, suggesting a role of sustained energetic abnormalities in evolving chamber dysfunction and remodeling. Indeed, reduced cardiac PCr/ATP observed at 3 wk strongly correlated with changes in EDV that developed over the ensuing 3 wk. These data suggest that abnormal energetics due to pressure overload predict subsequent LV remodeling and dysfunction

Isohemoglobin differentiation in the bimodal-breathing amazon catfish **Hoplosternum littorale**

The bimodal gill(water)/gut(air)-breathing Amazonian catfish Hoplosternum littorale that frequents hypoxic habitats uses 'mammalian' 2,3- diphosphoglycerate (DPG) in addition to 'piscine' ATP and GTP as erythrocytic O2 affinity modulators. Its electrophoretically distinct anodic and cathodic hemoglobins (Hb(An) and Hb(Ca) were isolated for functional and molecular characterization. In contrast to Hb(An), phosphate-free Hb(Ca) exhibits a pronounced reverse Bohr effect (increased O2 affinity with decreasing pH) that is obliterated by ATP, and opposite pH dependences of K(T) (O2 association constant of low affinity, tense state) and the overall heat of oxygenation. Dose-response curves indicate small chloride effects and pronounced and differentiated phosphate effects, DPG < ATP < GTP < IHP. Hb(Ca)-O2 equilibria analyzed in terms of the Monod-Wyman-Changeux model show that small T state bond energy differences underlie the differentiated phosphate effects. Synthetic peptides, corresponding to N-terminal fragment of the cytoplasmic domain of trout band 3 protein, undergo oxygenation-linked binding to Hb(Ca), suggesting a metabolic regulatory role for this hemoglobin. The amino acid sequences for the α and β chains of Hb(Ca) obtained by Edman degradation and cDNA sequencing show unusual substitutions at the phosphate-binding site that are discussed in terms of its reverse Bohr effect and anion sensitivities

Preterm birth is associated with lower academic attainment at age 12 years: a matched cohort study by linkage of population-based datasets

OBJECTIVE: To compare academic attainment at age 12 years in preterm children born below 30 weeks of gestation with matched term-born peers, using standardized, nationwide and well-validated school tests. STUDY DESIGN: This population-based, national cohort study was performed by linking perinatal data from the nationwide Netherlands Perinatal Registry with educational outcome data from Statistics Netherlands and included 4677 surviving preterm children born at 25 0/7-29 6/7 weeks of gestational age and 366 561 controls born at 40 weeks of gestational age in 2000-2007. First, special education participation rate was calculated. Subsequently, all preterm children with academic attainment test data derived at age 12 years were matched to term-born children using year and month of birth, sex, parity, socioeconomic status, and maternal age. Total, language, and mathematics test scores and secondary school level advice were compared between these 2 groups. RESULTS: Children below 30 weeks of gestation had a higher special education participation rate (10.2% vs 2.7%, P < .001) than term-born peers. Preterm children had lower total (-0.37 SD; 95% CI -0.42 to -0.31), language (-0.21 SD; 95% CI -0.27 to -0.15), and mathematics (-0.45 SD; 95%CI -0.51 to -0.38) z scores, and more often a prevocational secondary school level advice (62% vs 46%, P < .001). CONCLUSIONS: A substantial proportion of children born before 30 weeks of gestation need special education at the end of elementary schooling. These children have significant deficits on all measures of academic attainment at age 12 years, especially mathematics, compared with matched term-born peers