The activity of the plant mitochondrial inner membrane anion channel (PIMAC) of maize populations divergently selected for cold tolerance level is differentially dependent on the growth temperature of seedlings

The activity of the plant inner membrane mitochondrial anion channel (PIMAC) is involved in metabolite shuttles and mitochondrial volume changes and could have a role in plant temperature tolerance. Our objectives were to investigate (i) the occurrence and (ii) the temperature dependence of anion fluxes through PIMAC in mitochondria isolated from seedlings of three maize populations differing in terms of cold tolerance; and (iii) the relationships between the PIMAC activity kinetics and the level of cold tolerance. Populations were the source population (C0) and two populations divergently selected for high (C4H) and low (C4L) cold tolerance. Such divergently selected populations are expected to share most of their genes, with the main exception of those genes controlling cold tolerance. Arrhenius plots of PIMAC chloride fluxes showed a linear temperature dependence when seedlings were grown at 25 or 14°C, whereas a non-linear temperature dependence was found when seedlings were grown at 5°C, with or without acclimation at 14°C. The activation energy and other thermodynamic parameters of PIMAC activity varied depending on temperature treatments during seedling growth. When seedlings were grown at 14 and 5°C with acclimation, PIMAC activity of the C4H population increased, while that of C4L declined, as compared with the activities of seedlings grown at 25°C. These symmetric responses indicate that PIMAC activity changes are associated with genetically determined differences in the cold tolerance level of the investigated populations. We conclude that anion fluxes by PIMAC depend upon changes on growth temperature and are differentially related to the tolerance level of the tested populations.     

Tropane alkaloids from Schizanthus hookeri

Tropine, a pair of diastereoisomeric hygrolines and two new tropane alkaloids; 3α-senecioyloxytropan-6β-ol and 6β-angeloyloxytropan-3α-ol, were isolated from roots of Schizanthus hookeri.     

Oral supplements of vitamin E improve measures of oxidative stress in plasma and reduce oxidative damage to LDL and erythrocytes in β-thalassemia intermedia patients

Fifteen β-thalassemia intermedia patients, not requiring chronic transfusional therapy, were monitored in order to check their antioxidant status, and the lipid oxidation products in plasma, LDL, and erythrocytes before and during a 9-month oral treatment with 600 mg/day vitamin E. The low level of vitamin E, and high level of malondialdehyde in plasma clearly tended to normalize after three months (P<.001), and were quite similar to control after six months. The abnormally low level of vitamin E in LDL and the four times higher than control basal level of conjugated dienes (LDL-CD), were not modified after three months of treatment. Significant changes of LDL-VE (P<.05) and of the basal LDL-CD (P<.001) were evident after six months. LDL-VE was within the normal range after nine months, whereas LDL-CD still appeared twice as higher than control.

Plasma vitamin A, ascorbate, β-carotene, and lycopene increased markedly at the end of the trial (P<.005).

The level of vitamin E in red blood cells was normalized after six months of supplementation. A decrease of the baseline value of conjugated dienes was observed after nine months, although it remained 1.4-fold higher than control. The RBC count and hematocrit appeared higher at the end of the trial (P<.05 and P<.001, respectively). The hemoglobin value did not show variations. A shift to normal of the resistance of erythrocytes to osmotic lysis was observed.

Our findings provide evidence that an oral treatment with vitamin E improves the antioxidant/oxidant balance in plasma, LDL particles, and red blood cells, and counteracts lipid peroxidation processes in β-thalassemia intermedia patients.     

An approach for identifying the influence of carcass type and environmental features on sarcosaprophagous Diptera communities

Summary. Since the entomosarcosaprophagous community is affected by environmental variables, it needs to be studied under different environmental conditions. In addition, because most studies are usually conducted with biomodels rather than human corpses, it is necessary to verify whether or not the type of decomposing animal matter affects the decomposition process itself, as well as the related fauna. For this reason, a study was conducted on the sarcosaprophagous Diptera community in two different environments of the Region of Murcia (SE Spain), using piglet and chicken carcasses, and Schoenly traps as collecting devices. To analyse possible differences regarding faunal composition among samples, a one-way Permutational Multivariate Analysis of Variance (PERMANOVA) was applied. The results indicate significant differences concerning the bait. In this sense, Calliphoridae, Muscidae, Fanniidae and Sarcophagidae families are the main groups responsible for such differences. In terms of environment-related differences, the only species that contribute are those of the dominant families, Calliphoridae and Muscidae.     

Plasma beta-endorphin in response to oral glucose tolerance test in obese patients

In order to clarify the possible interaction between endogenous opioids and glucose homeostasis in obesity we studied Beta-Endorphin (B-Ep), ACTH, cortisol and insulin plasma levels in response to an oral glucose tolerance test (OGTT) in 8 females suffering from uncomplicated obesity and in 6 healthy volunteers of normal weight. Results were evaluated in terms of secretion areas subtracted from basal value. Basal glucose, insulin and B-Ep levels were significantly higher in the obese patients compared to controls, cortisol levels and ACTH were not statistically different between obese and normal subjects. During OGTT total areas of insulin secretion were significantly higher in the obese patients; cortisol, ACTH, B-Ep plasma levels did not change in controls, whereas obese patients showed a response to B-Ep which reached a peak at 60 minutes. The area of B-Ep response to OGTT in obese patients was significantly higher than in controls. On the basis of these results we may suggest that the opioid system belongs to the chain of neuroendocrine and metabolic events responsible for the origin and the growth of overweight. But the possibility exists that obesity itself can enhance the B-Ep secretion above all through overeating. In this regard it is to stress that glucose ingestion induces in obese patients, differently from normal subjects, insulin hypersecretion and the B-Ep secretion, possibly from gastro-enteric tract and/or pancreatic isles.     

The Effect of Temperature on the Energy of Activation of Spinach Ferredoxin-NADP+ Oxidoreductase

A non-linear Arrhenius plot of diaphorase activity of the membrane-boundferredoxin-NADP+ oxidoreductase of thylakoids, showed a breakat 25–30°C, whereas a straight-line was obtained forthe soluble reductase. The E_a values of the thylakoid-boundenzyme was 4–7 and 15–18 kj/mol above and belowthe transition temperature, respectively. In contrast, the E_aobtained for the soluble enzyme was in the range 25–30kj/mol. An Arrhenius plot with similar transition to that ofthylakoids, but with higher E_a values, was obtained when thereductase was isolated as a complex closely associated withthe 17.5 kDa-intrinsic polypeptide. The differences in H* and in S* values below and above the transitiontemperature for thylakoids and the complex were almost the samesuggesting that lipids were not important for the transition. Comparing the H* and S* values for the diaphorase activity ofsoluble and membrane-bound enzyme suggest that the conformationof the latter is more favorable for catalysis. ¹Present address: Depto. de Bioquímica, Fac. de Biologiay C.S.I.C., Univ. de Sevilla, Apdo. 1095, 41080-Sevilla, Spain (Received May 1, 1986; Accepted June 18, 1986)     

Effects of a Mild and Prolonged Restriction in Sodium or Food Intake on the Circadian Rhythm of Aldosterone and Related Variables

The effect of a mild reduction in dietary sodium intake (-30 mEq/24 hr) and body weight (-2 kg/2 months) on circadian rhythms of urinary aldosterone (UA), sodium (UNa), potassium (UK), creatinine (UC) and volume (UV) have been investigated in nine clinically healthy subjects. The mild reduction in dietary sodium is associated with: (1) a decrease in the 24-hr excretion rate of UNa, UK and UV, and an increased mesor of UA and UC; (2) a lowered extent of the circadian variation for UNa, UK, UV and a greater amplitude for UA and UC (3) a later crest in the temporal phase for UK, UA, UC, an earlier phasic wave for UNa. The mild reduction in calorie intake resulting in a body weight loss is associated with a more pronounced decrease in the 24-hr excretion rate of UNa and UK, and in the extent of circadian fluctuation for UNa. Peculiar events are: (1) the decreased 24-hr excretion rate for UA, and the increased mesor for UV; (2) the extent variability increased for UV, decreased for UC. Such effect may have a practical resonance for heuristic physiology since the role of dietary sodium and food intake has been better clarified. Dietary sodium and food can be regarded as 'chronomodulatory agents' for the adrenal cortex since their adrenotropic influence is extended to the tonic as well as phasic secretion of aldosterone.