Elucidating genomic regions determining enhanced leaf growth and delayed senescence in elevated CO2.

Limited information is available on the genetic variation and control for plant growth response to elevated CO(2) (e[CO(2)]). Such information is necessary to understand plant adaptation and evolution in future rising CO(2). Here, quantitative trait loci (QTL) for leaf growth, development, quality and leaf senescence were determined in a tree pedigree - an F(2) hybrid of Populus trichocarpa T. & G and Populus deltoides Marsh, following season-long exposure to either current day ambient carbon dioxide (a[CO(2)]) or e[CO(2)] at 600 microL L(-1). Leaf growth and development differed between the grandparents such that P. trichocarpa showed greater response to e[CO(2)]. In the F(2) generation, leaf development and quality traits including leaf area, leaf shape, epidermal cell area, and stomatal number, specific leaf area (SLA), and the phenology trait, canopy senescence index, were sensitive to e[CO(2)]. Sixty-nine QTL were mapped for the 19 traits of plants in a[CO(2)] while 60 QTL were mapped for plants in e[CO(2)]. The results suggest that although many QTL mapped to common positions in a[CO(2)] and e[CO(2)], confirming their importance in determining growth, there was also differential genetic control for a number of traits including leaf senescence. Candidate genes were shown to collocate to regions where response QTL mapped. This study is the first to identify candidate genes that may be important in determining plant adaptation to future high-CO(2) world.

A differential response to nortriptyline and fluoxetine in melancholic depression: the importance of age and gender.

OBJECTIVE: To consider the impact of age and gender on the antidepressant response to nortriptyline and fluoxetine in melancholic depression. METHOD: Of 191 depressed patients, 113 met study criteria for melancholia. All patients were randomized to receive either fluoxetine or nortriptyline. Response rates, defined as an improvement of 60% or more on the Montgomery Asberg Depression Rating Scale over 6 weeks of antidepressant treatment on an intention to treat basis, were examined by age, and by age and gender. RESULTS: Melancholic depressed patients 40 years or older, especially men, had a markedly superior response to nortriptyline compared with fluoxetine. Conversely, melancholic depressed patients, age 18-24 years, especially women, had a markedly superior response to fluoxetine. CONCLUSION: Age and gender appear to be critical variables in understanding differential antidepressant responses to tricyclic antidepressants and selective serotonin reuptake inhibitors in melancholic depression.

Leaf stomatal and epidermal cell development: identification of putative quantitative trait loci in relation to elevated carbon dioxide concentration in poplar.

Genetic variation in stomatal initiation and density, and epidermal cell size and number were examined in a hybrid pedigree of Populus trichocarpa T. & G. and P. deltoides Marsh in both ambient ([aCO2]) and elevated ([eCO2]) concentrations of CO2. We aimed to link anatomical traits with the underlying genetic map of F2 Family 331, composed of 350 markers across 19 linkage groups. Leaf stomatal and epidermal cell traits showed pronounced differences between the original parents. We considered the following traits in the F2 population: stomatal density (SD), stomatal index (SI), epidermal cell area (ECA) and the number of epidermal cells per leaf (ECN). In [eCO2], adaxial SD and SI were reduced in the F2 population, whereas ECA increased and ECN remained unchanged. In [aCO2], four putative quantitative trait loci (QTL) with logarithm of the odds ratio (LOD) scores greater than 2.9 were found for stomatal traits on linkage group B: adaxial SI (LOD scores of 5.4 and 5.2); abaxial SI (LOD score of 3.3); and SD (LOD score of 3.2). These results imply that QTL for SI and SD share linkage group B and are under genetic control. More moderate LOD scores (LOD scores >/= 2.5) suggest QTL for SI on linkage groups A and B and for SD on linkage groups B, D and X with a probable co-locating quantitative trait locus for SI and SD on linkage group D (position 46.3 cM). The QTL in both [aCO2] and [eCO2] for adaxial SD were co-located on linkage group X (LOD scores of 3.5 and 2.6, respectively) indicating a similar response across both treatments. Putative QTL were located on linkage group A (position 89.2 cM) for both leaf size and ECN in [aCO2] and for ECA at almost the same position. The data provide preliminary evidence that leaf stomatal and cell traits are amenable to QTL analysis.

Psychoses associated with thyrotoxicosis - 'thyrotoxic psychosis.' A report of 18 cases, with statistical analysis of incidence.

OBJECTIVE: To report a series of newly diagnosed thyrotoxic patients with concurrent acute psychosis, and to assess the association between the two disorders. DESIGN: Retrospective study of thyrotoxic patients with associated psychosis ('thyrotoxic psychosis'; TP) requiring inpatient psychiatric care. New Zealand thyrotoxicosis annual incidence figures and first psychiatric admission rates for affective psychosis were utilised to statistically assess the co-occurrence of thyrotoxicosis and affective psychosis. PATIENTS AND METHODS: During the 20-year study period, 18 inpatients (16 women and 2 men), mean age 54 years, with TP were identified. No patient had a past history of thyrotoxicosis, but four had required psychiatric inpatient care many years earlier. Thyrotoxicosis was documented by radioimmunoassay of thyroid hormone levels, and thyroid scintiscan. Psychiatric manifestations were classified using ICD9 criteria. RESULTS: Thyroid hormone levels were markedly elevated in more than half of our TP patients. All younger patients had Graves' disease, and most older patients toxic nodular goitre. All patients were treated with antithyroid drugs, and all but one subsequently received (131)I therapy. Two patients were not mentally ill when thyrotoxicosis was diagnosed, but suffered major mood swings when thyroid hormone levels were falling. There was no specific psychiatric clinical picture but affective psychoses were commonest - seven depression, seven mania. The other diagnoses were two schizophreniform, one paranoid, and one delirium. Initially, neuroleptic medication was used in all but one patient, and during long-term follow-up (median 11 years) more than half our series had remained well with no further psychiatric problems. Statistical analysis was restricted to thyrotoxic patients with first psychiatric hospital admission for affective psychosis. During the 20-year period, there were nine thyrotoxic patients (95% confidence interval 4.5-17.1) with concurrent affective psychosis requiring first admission, and the calculated expected number was only 0.36. These findings indicate a clear association well above chance co-occurrence. CONCLUSION: TP is not a specific clinical picture, but affective psychoses are commonest. Statistical analysis of thyrotoxic patients with concurrent affective psychoses showed an incidence well above chance co-occurrence. It appears that thyrotoxicosis may be a precipitant of acute affective psychosis.