Cytochemical and histochemical characterization of cotyledonary bodies from Pharbitis nil seedlings

Cytological and histochemical characterization of the structures from which an obscure substance is secreted via open stomata to the abaxial surface of Japanese morning glory (Pharbitis nil Choisy cv. Violet) cotyledons has been carried out. Observation of intact cotyledons using the light microscope revealed randomly distributed semi-transparent structures. These structures, which were shown to be the same as those previously described as giant oil cells are referred to here as cotyledonary bodies. These bodies can be eas- ily isolated and purified after enzymatic digestion of the cotyledons. Using different staining procedures we have confirmed that each cotyledonary body originates from an individual mesophyll cell dur- ing embryo development. Purified bodies consist of (i) a thick shell- like envelope; (ii) a transparent, hydrophilic zone; (iii) a hydropho- bic core. Hydrophobic contents of the bodies were readily extracted with methanol and shown to contain fatty acids and phenolic com- pounds using the gas chromatography/mass spectrometry (GC/MS) technique. Methanolic extracts of cotyledonary bodies showed high fluorescence with two excitation and emission maxima. Using a flu- orescence microscope we have shown that the bodies isolated from seedlings grown in continuous light, conditions non-inductive for flowering, and those grown under conditions inductive for flowering (a single 16 h, long dark period) have different fluorescence emis- sion spectra. Different levels of free Ca 2+ inside cotyledonary bodies isolated from light-grown and single dark-period treated P. nil seed- lings were found using the fluorescent calcium indicator dye Fluo-3 under a confocal scanning laser microscope. On the basis of these observations we speculate that cotyledonary bodies could be in- volved in floral induction

Photomorphogenic mutants of tomato

Photomorphogenesis of tomato is being studied with the aid of mutants which are either modified in their photore- ceptor composition or in their signal transduction chain(s) . Several mutants affecting the phytochrome family of photoreceptors, some of which appear deficient for specific genes encoding phytochrome apoproteins have been isolated . In addition, other mutants, including transgenic lines overexpressing phytochrome A, exhibit exaggerated photomorphogenesis during de-etiolation . Anthocyanin biosynthesis and plastid development are being used as model systems for the dissection of the complex interactions among photomorphogenic photoreceptors and to elucidate the nature of their transduction chains

Effect of the 5-HTTLPR polymorphism on affective temperament, depression and body mass index in obesity

Background and aim: Many studies show high prevalence of affective disorders in obese patients. Affective temperament is a subclinical manifestation of such conditions. The 5-HTT gene encoding the serotonin transporter may be involved in both mood and eating dysregulation. The aim of this study was to investigate the influence of a polymorphism in the 5-HTT gene on affective temperament types, depressive symptoms and Body Mass Index (BMI) in obese patients. Methods: This study involved 390 patients (237 females, and 153 males) with obesity. The TEMPS-A questionnaire, Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HDRS) were used to evaluate affective temperaments and prevalence of depression. DNA was obtained for serotonin transporter gene-linked polymorphism (5-HTTLPR) genotyping. Results: In obese patients S/S genotype was associated with depressive and L/L with cyclothymic temperament. Subjects with L/L genotype presented significantly higher BMI and greater intensity of depressive symptoms in BDI and HDRS. Females scored higher in anxious and depressive, while males in hyperthymic, cyclothymic and irritable temperaments. Females scored higher in BDI (subjective depression) while males in HDRS (objective depression). Limitations: TEMPS-A, BDI and HDRS are frequently used in studies on affective disorders. However, these methods do not examine all dimensions of mood and personality. Conclusions: In obese patients S allele of 5-HTTLPR was associated with development of depressive temperament while L allele corresponded with greater obesity and prevalence of depression. Different mechanisms may be involved in manifestation of depression in males and females with obesity