Iron-sulfur centers in the photosynthetic reaction center complex fromChlorobium vibrioforme. Differences from and similarities to the iron-sulfur centers in Photosystem I

The photosynthetic reaction center complex from the green sulfur bacteriumChlorobium vibrioforme has been isolated under anaerobic conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals polypeptides with apparent molecular masses of 80, 40, 30, 18, 15, and 9 kDa. The 80- and 18-kDa polypeptides are identified as the reaction center polypeptide and the secondary donor cytochromec ₅₅₁ encoded by thepscA andpscC genes, respectively. N-terminal amino acid sequences identify the 40-kDa polypeptide as the bacteriochlorophylla-protein of the baseplate (the Fenna-Matthews-Olson protein) and the 30-kDa polypeptide as the putative 2[4Fe-4S] protein encoded bypscB. Electron paramagnetic resonance (EPR) analysis shows the presence of an iron-sulfur cluster which is irreversibly photoreduced at 9K. Photoaccumulation at higher temperature shows the presence of an additional photoreduced cluster. The EPR spectra of the two iron-sulfur clusters resemble those of F_A and F_B of Photosystem I, but also show significantly differentg-values, lineshapes, and temperature and power dependencies. We suggest that the two centers are designated Center I (with calculatedg-values of 2.085, 1.898, 1.841), and Center II (with calculatedg-values of 2.083, 1.941, 1.878). The data suggest that Centers I and II are bound to thepscB polypeptide.     

Sulphamerazine toxicity in cut-throat trout broodfish Salmo clarki (Richardson)

Treatment of cut-throat trout broodfish Salmo clarki (Richardson) with Sulphamerazine at 220 mg/kg (10 g/100 1b) of fish/day for 14 days resulted in severe kidney histopathology and increased mortality among males. Experimental data presented showed that cut-throat trout broodfish were extremely sensitive to Sulphamerazine toxicity. Hydropic degeneration of renal tubule epithelium and haemorrhage into tubule lumens were observed in kidneys of both male and female trout, but was more severe in the former. Death, which occurred only in males, was correlated with spawning stress and impaired renal function.     

Thrombocyte substitution in acute leukemia. Effect of histocompatibility on the clinical efficacy

Thrombocyte substitution is an essential prerequisite for intensive cytoreductive therapy in acute leukemia. Evaluating 228 thrombocyte transfusions in 17 patients shows that the clinical effectiveness of thrombocyte concentrates can be increased by making the coordination of HLA antigens of donor and receiver as good as possible. When measured in the corrected increment (CI) 24 hours after transfusion, the effectiveness of A3/B1 match preparations (CI = 7.0 +/- 1.6) is significantly higher than that of random preparations (CI = 3.0 +/- 0.5). With the presence of HLA antibodies an effective substitution (CI24 greater than or equal to 4.5) can only be achieved by A3/B1 match thrombocytes. This can only be realized by applying the fourfold thrombapheresis of single donors.     

Growth,water and nutrient status of plants in relation to patterns of variations in concentrations of dry matter and nutrient elements in base-to-top leaves

Summary Patterns of variations in dry matter concentrations in tomato plants reflected production and translocation of dry matter, implying the possibility of controlling and regulating growth and development of plants by use of dry matter concentration as a useful parameter.Dry matter concentrations, analogous to nutrient concentrations, varied depending on growth conditions, and on type, age and position of plant organs.Interpretation of patterns of variations in contents and concentrations of leaf dry matter in plants, grown under widely different conditions, agreed with the source/sink hypothesis.High water applications were associated with high dry matter concentrations in upper leaves of young pot plants with low sink capacity and with low dry matter concentrations in leaves of older, trough-grown plants with high sink capacity.Accumulation of dry matter in upper leaves of plants is suggested to be associated with development of secondary sinks and, accumulation of dry matter in lateral shoots is considered as a possible explanation of apical dominance.Water regime and transpiration influenced distribution of contents of dry and fresh matter and of absorbed nutrient elements. Redistribution was influenced by water regime.The term, distribution is in the following used in connection with not only absolute values (contents) but also relative values (concentrations).     

Tranylcypromine: stimulation of eating through alpha-adrenergic neuronal system in the paraventricular nucleus.

Injection of norepinephrine (NE) into the paraventricular nucleus of the hypothalamus has been shown to elicit eating in satiated rats. In the present study, the monoamine oxidase inhibitor tranylcypromine (TCP), which is known to release endogenous NE, was found to produce a similar effect in rats maintained and tested on a palatable milk-mash combination diet. The effect of this antidepressant drug was positively correlated in magnitude with the NE effect in the same animals. It was selectively antagonized by central injection of drugs which block α-adrenergic receptors. Local pretreatment with NE synthesis inhibitors similarly blocked the TCP eating response but had no effect on eating elicited by exogenous NE. It is suggested from these results that TCP is stimulating eating through the release of endogenous NE from adrenergic neurons innervating the region of the paraventricular nucleus.     

Somatostatin as a mediator of the effect of neurotensin on pentagastrin-stimulated acid secretion in rats

Neurotensin and somatostatin have both been shown to inhibit gastric acid secretion, but no interaction between these peptides has been demonstrated. To determine whether somatostatin might be a mediator of neurotensin's effect on pentagastrin-stimulated gastric acid secretion, we performed the following three experiments. First, we collected 0.2-ml samples of portal venous blood as frequently as every 5 min, and we confirmed a significant release of somatostatin-like immunoreactivity into portal venous blood during neurotensin-induced inhibition of acid secretion. This release of somatostatin-like immunoreactivity and inhibition of acid secretion were only seen in pentobarbital-anesthetized rats, but no sustained release of somatostatin-like immunoreactivity or inhibition of acid secretion occurred in urethane-anesthetized animals. In the second experiment, we analyzed portal plasma by high pressure liquid chromatography, and found that portal somatostatin-like immunoreactivity in blood collected during neurotensin infusion was composed of a single peak corresponding to somatostatin-14. In the third experiment, we found that infusion of antibody to somatostatin prevented neurotensin from inhibiting pentagastrin-stimulated acid secretion. Taken together, these data show that somatostatin, possibly from the stomach itself, is a necessary mediator of neurotensin's inhibitory effect in pentobarbital-anesthetized rats.     

Extraction and measurement of myocardial nucleotides, nucleosides, and purine bases by high-performance liquid chromatography

Nucleotides, nucleosides, and purine bases were extracted from human endomyocardial biopsies, freeze-clamped rat hearts, and porcine coronary sinus plasma. Perchloric acid extracts were neutralized with Freon-trioctylamine and analyzed at 250 nm by reverse-phase ion-pairing high-performance liquid chromatography. To achieve the sensitivity necessary for analyzing small (1-3 mg wet wt) tissue samples, a small-bore, 2.1-mm-internal-diameter, C18, 5-micron reverse-phase column and a flow rate of 0.2 ml/min were used. All of the myocardial nucleotides and AMP degradation products were resolved in a total separation time of 27 min with 30 mM KH2PO4, 7.5 mM tetrabutylammonium phosphate buffers, and binary pH and acetonitrile gradients.     

Thyroid stimulating immunoglobulins in patients in long-term remission after Graves' disease

Thyroid stimulating antibodies (TSAb) and thyrotropin binding inhibiting immunoglobulins (TBII) were measured in 32 patients with Graves' disease who had been in remission for at least two years after treatment was been stopped. Seventeen patients had been treated with antithyroid drugs, and 15 patients with 131Iodine. In the first group 3 of 17 patients had TSAb and one TBII, whereas in the second group 4 of 15 patients had TSAb and two TBII. One patient from each group had inhibiting TSAb. During the follow-up one patient from each group relapsed, whereas 5 patients from the second group developed myxoedema. No relationship between the clinical outcome and TSAb and TBII was found.