Brine residues and organics in the Urvara basin on Ceres

Ceres is a partially differentiated dwarf planet, as confirmed by NASA's Dawn mission. The Urvara basin (diameter ~170 km) is its third-largest impact feature, enabling insights into the cerean crust. Urvara's geology and mineralogy suggest a potential brine layer at the crust-mantle transition. Here we report new findings that help in understanding the structure and composition of the cerean crust. These results were derived by using the highest-resolution Framing Camera images acquired by Dawn at Ceres. Unexpectedly, we found meter-scale concentrated exposures of bright material (salts) along the crater's upper central ridge, which originate from an enormous depth, possibly from a deep-seated brine or salt reservoir. An extended resurfacing modified the southern floor ~100 Myr after crater formation (~250 Myr), long after the dissipation of the impact-generated heat. In this resurfaced area, one floor scarp shows a granular flow pattern of bright material, showing spectra consistent with the presence of organic material, the first such finding on Ceres beyond the vast Ernutet area. Our results strengthen the hypothesis that Ceres is and has been a geologically active world even in recent epochs, with salts and organic-rich material playing a major role in its evolution.

Photoproduction of eta-mesic 3He

The photoproduction of eta-mesic 3He has been investigated using the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI. The total inclusive cross section for the reaction gamma3He-->etaX has been measured for photon energies from threshold to 820 MeV. The total and angular differential coherent eta cross sections have been extracted up to energies of 745 MeV. A resonancelike structure just above the eta production threshold with an isotropic angular distribution suggests the existence of a resonant quasibound state. This is supported by studies of a competing decay channel of such a quasibound eta-mesic nucleus into pi(0)pX. A binding energy of (-4.4+/-4.2) MeV and a width of (25.6+/-6.1) MeV is deduced for the quasibound eta-mesic state in 3He.

The reaction gammap-->pi0gamma'p and the magnetic dipole moment of the Delta+ 1232 resonance

The reaction gammap-->pi(0)gamma'p has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between sqrt[s]=1221-1331 MeV. The cross section's differential in angle and energy have been determined for the photon gamma' in three bins of the excitation energy. This reaction channel provides access to the magnetic dipole moment of the Delta(+)(1232) resonance and, for the first time, a value of mu(Delta(+))=[2.7(+1.0)(-1.3)(stat)+/-1.5(syst)+/-3(theor)]mu(N) has been extracted.

In-medium modifications of the pipi interaction in photon-induced reactions

Differential cross sections of the reactions (gamma,pi(0)pi(0)) and (gamma,pi(0)pi(+/-)) have been measured for several nuclei (1H,12C, and (nat)Pb) at an incident-photon energy of E(gamma)=400-460 MeV at the tagged-photon facility at MAMI-B using the TAPS spectrometer. A significant nuclear-mass dependence of the pipi invariant-mass distribution is found in the pi(0)pi(0) channel. This dependence is not observed in the pi(0)pi(+/-) channel and is consistent with an in-medium modification of the pipi interaction in the I=J=0 channel. The data are compared to pi-induced measurements and to calculations within a chiral-unitary approach.

Effects of NH(4)(+), NO(3)(-) and HCO(3)(-) on apoplast pH in the outer cortex of root zones of maize, as measured by the fluorescence ratio of fluorescein boronic acid

A fluorimetric ratio technique was elaborated to measure apoplastic pH in the outer root cortex of maize (Zea mays L.) grown hydroponically. A newly synthesized fluorescent probe, fluorescein boronic acid (pK(a) = 5.48), which covalently binds to the cell wall of the outer cell layers, was used. Under conditions of saturating ion concentrations the apoplastic pH was determined along the root axis ranging from 1 to 30 mm behind the root tip. Apoplastic pH was recorded for root segment areas (1 mm(2)), and pH values of high statistical significance were obtained. With an external solution of pH 5, the apoplastic pH was about pH 5.1 in the division zone, between pH 4.8 and 4.9 in the elongation region and about pH 4.9 in the root hair zone. At an external pH of 8.6, the difference between the external pH and the apoplastic pH was considerably more, with a pH of 5.2-5.3 in all root zones. Addition of 1 mM NH(4)(+) caused a small apoplastic pH decrease (0.05 of a pH unit) in all root zones. Apoplastic alkalization upon application of 6 mM NO(3)(-) was highest (0.3 of a pH unit) in the zone where root hairs emerge; in the division and early elongation zones, apoplastic pH increased only transiently. In the presence of 10 mM HCO(3)(-), NO(3)(-) elicited a higher and persistent alkalization (0.06-0.25 of a pH unit) in all root zones. Application of fusicoccin reduced apoplastic pH from 4.85 to 4.75 in the elongation zone, while inhibition of the H(+)-ATPase with vanadate alkalized the apoplast in the root hair zone from pH 5.4 to 5.6. The observed pH differences along the root axis upon differential N supply and application of HCO(3)(-) provide evidence that this new pH technique is a useful tool with which to measure apoplastic pH, and in future may permit measurements at microsites at the cell level by use of microscope imaging.

The effects of patellar taping on stride characteristics and joint motion in subjects with patellofemoral pain

Although patellar taping has been reported to be effective in reducing pain, the effects of this procedure on functional outcomes, such as ambulation, have not been documented. The purpose of this study was to compare stride characteristics and joint motion in subjects with patellofemoral pain, with and without the application of patellar taping using the McConnell technique. Fifteen female subjects between the ages of 14 and 41 years with diagnosis of patellofemoral pain participated in this study. Stride characteristics (Stride Analyzer) and sagittal plane joint motion (VICON) were recorded simultaneously during taped and untaped trials of free walking, fast walking, and ascending and descending a ramp and stairs. A repeated measures analysis of variance was used to determine differences between taped and untaped trials. Although subjects reported an average pain reduction of 78% using a visual analogue scale, the only significant change in stride characteristics was an increase in stride length during ramp ascent. Patellar taping did, however, result in a small but significant increase in loading response knee flexion across all conditions tested. We believe this finding demonstrates more willingness by the patellofemoral pain subjects to load the knee joint, thus permitting increased shock absorption, increased quadriceps activity, and tolerance of increased patellofemoral joint reaction force.

In vivo effects of fluconazole on lymphocyte subpopulations of the thymus and spleen in mice: flow cytometry analysis

Fluconazole is a triazole compound developed for the therapy of fungal infections, especially for systemic fungal infections. In this study 2.5 and 5.0 mg oral doses of fluconazole per kg of body weight were administered to mice for 3-28 days, followed by lymphocyte phenotyping by flow cytometry analysis on a Becton-Dickinson FACScan. The results show that administration of fluconazole neither reduced body and organ weights nor thymocyte and spleen cell count. In the thymus and spleen the distribution of all the lymphocyte subpopulations studied was unchanged. These results suggest that fluconazole has no in vivo effects on the quantity of lymphocyte subpopulations in mice. The results tend to support the use of fluconazole in immunosuppressed patients.

Thermolabile hemoglobin formation by 2-cyanaziridine derivatives

The erythrocyte toxicity of imexone, azimexone, ciamexone, and its derivatives was assessed by means of the thermolabile hemoglobin formation test. After administration of doses up to 500 mg/kg to mice, imexone had no effect, whereas in accordance with previous studies azimexone strongly and ciamexone moderately enhanced thermolabile hemoglobin formation. With regard to the derivatives (metabolites) of ciamexone, the alcohol was as active as ciamexone itself, whereas ciamexone aldehyde gave a weak reaction. Both ciamexone acid and ciamexone-cysteine had no influence. Demethyl ciamexone, however, was more toxic than ciamexone, further indicating that the metabolic oxidation of the methyl group represents a detoxifying step. In contrast to the in vivo results, after incubation with blood samples solely imexone (in the range of mg/ml blood) but none of the other 2-cyanaziridines enhanced thermolabile globin formation. Preincubation of imexone with cysteine inhibited this effect. The results are discussed in view of the hypothesis that binding of the nitrile group of the 2-cyanaziridines to mercapto groups of proteins precedes their biological effects.

No influence of cadmium on the production of specific antibodies in mice

The in vivo effect of cadmium on specific antibody production of the immune system was investigated in mice. Female Balb/c mice were given 1, 10 or 100 ppm cadmium as cadmium chloride in the drinking water for 7, 14, 21, 28, 60 or 90 days. Immunization of the mice was carried out twice with a specific antigen (dinitrophenyl-bovine serum albumin) at an interval of 14 days. The antibodies (IgM and IgG) produced by this antigen were determined jointly with the aid of ELISA on days 0, 7, 14, and 21 after the first sensitization. The leucocyte count in the blood of the animals exposed to cadmium was unchanged. In spite of marked spleen and thymus atrophy in the 100-ppm group, the measurement of antibody concentrations in the blood, also, did not show any significant differences from controls. Our results show that orally administered cadmium at the doses selected does not have any effect on the specific antibody production and thus on the most important function of the humoral immune system. The marked loss of weight of the thymus, however, does suggest there were effects on the cellular immune system.

Effect of Low Root Medium pH on Net Proton Release, Root Respiration, and Root Growth of Corn (Zea mays L.) and Broad Bean (Vicia faba L.)

The effect of low pH on net H(+) release and root growth of corn (Zea mays L.) and broad bean (Vicia faba L.) seedlings was investigated in short-term experiments at constant pH. Broad bean was more sensitive to low pH than corn: the critical values (pH values below which net H(+) release and root growth ceased) were pH 4.00 (broad bean) and pH 3.50 (corn) at 1 millimolar Ca(2+). Both proton release and root growth were progressively inhibited as the medium pH declined. Additional Ca(2+) in the root medium helped to overcome the limitations of low pH for net H(+) release and root growth. Potassium (for corn) and abscisic acid (for broad bean) increased both net H(+) release and root growth rate at the critical pH value. It is concluded that poor root growth at low pH is caused by a lack of net H(+) release that may decrease cytoplasmic pH values. Inhibited net H(+) release at high external H(+) activity is not due to a shortage of energy supply to the H(+) ATPase. Instead, a displacement of Ca(2+) by H(+) at the external side of the plasmalemma may enhance reentry of H(+) into root cells.

Thiosulphate and hydroxocobalamin prophylaxis in progressive cyanide poisoning in guinea-pigs

The duration of action of the cyanide antidotes sodium thiosulphate and hydroxocobalamin was investigated in guinea-pigs after prophylactic administration before a long-term infusion of NaCN. The parameter for the diminution of the antidote action was the point of time at which the concentration of HCN in the exhaled air of the animals exceeded 100 nmol/kg per min. The time taken to reach this threshold level in the control animals was 12 min. While the threshold level could be extended only to 35 min with hydroxocobalamin (300 mg/kg i.v.) the protective action of sodium thiosulphate (100, 500 and 1000 mg/kg i.v.) persisted dose dependently for about 1, 2 and 4 h, respectively. Additionally we found a plasma half-life of sodium thiosulphate in guinea-pigs of 26 min. This value corresponds approximately to the plasma half-life of sodium thiosulphate in humans given in the literature. Because of the large injection volume necessary, sodium thiosulphate is not suitable for prophylactic use in man.

Active extrusion of protons into deionized water by roots of intact maize plants

The investigations were focussed on the question as to whether roots of intact maize plants (Zea mays L. cv Blizzard) release protons into deionized H(2)O. Plants in the six to seven leaf stage depressed the pH of deionized H(2)O from 6 to about 4.8 during an experimental period of 4 hours. Only one-third of the protons released could be ascribed to the solvation of CO(2) in H(2)O. The main counter anions released were Cl(-), NO(3) (-), and SO(4) (2-). At low temperature (2 degrees C), the H(+) release was virtually blocked while a relatively high amount of K(+) was released. The presence of K(+), Na(+), Ca(2+), and Mg(2+) in the external solution increased the H(+) secretion significantly. Addition of vanadate to the outer medium inhibited the H(+) release while fusicoccin had a stimulating effect. Substituting the nutrient solution of deionized H(2)O resulted in a substantial increase of the membrane potential difference from -120 to -190 millivolts. The experimental results support the conclusion that the H(+) release by roots of intact maize plants is an active process driven by a plasmalemmalocated ATPase. Since the net H(+) release was not associated with a net uptake of K(+), it is unlikely to originate from a K(+)/H(+) antiport.

The influence on the formation of unstable haemoglobin by the immunomodulating 2-cyanaziridines azimexone and BM 41.332 in mice

Azimexone causes in mice the formation of unstable haemoglobins after a single dose of 20 mg/kg. BM 41.332, another immunomodulating drug of the 2-cyanaziridine class, induces these unstable haemoglobins only after a single oral administration of 500 mg/kg. Subsequently to the formation of unstable haemoglobins we observed a development of Heinz bodies. These effects of the 2-cyanaziridines were elicited neither by methaemoglobin formation nor by an impairment of the components protecting haemoglobin against oxidation (G6PD, catalase, glutathione). The elimination of the altered haemoglobin in the spleen could be followed by measurement of the rise in the iron content of the spleen.

Comparative investigations of various immunoregulatory substances in the delayed type hypersensitivity test of the mouse

The substances D-penicillamine, auranofin, chloroquine, levamisole, BM 41.332, azimexone, bestatin, methisoprinol (inosiplex), thymosine (fraction 5), indomethacin and cyclophosphamide were examined comparatively in the delayed type hypersensitivity test after oxazolone sensitisation in mice. It was found, that only the basal antirheumatic drugs D-penicillamine, auranofin, chloroquine and levamisole and also BM 41.332 led to a potentiation of the DTH reactions. Methisoprinol, bestatin, azimexone, thymosine fraction 5 and indomethacin had no effect on the DTH, whilst the immunosuppressant cyclophosphamide led to an inhibition of the DTH reaction. It is concluded that this pharmacological model is suitable for screening of new basal drugs for rheumatoid arthritis.

The effect of low lead doses in vitro and in vivo on the d-ala-d activity of erythrocytes, bone marrow cells, liver and brain of the mouse

The d-ala-d activity in erythrocytes (RBC), femur bone marrow, liver and brain of mice was determined using a modification of the method of Berlin and Schaller (1974). In vitro incubation of lead acetate (PbAc) with these tissues resulted in a dose-dependent inhibition of the d-ala-d activity. The lead concentration which caused a 50% inhibition of the d-ala-d activity after 10 min incubation [ED-50(10 min)] was 0.78 mg PbAc/femur bone marrow, 3.72 micrograms PbAc/ml RBC, 15.85 micrograms PbAc/g brain and 43.05 micrograms PbAc/g liver. An increase in the incubation time to 60 min reduced these ED-50 values between 44% for the erythrocytic enzyme and 67% for the brain enzyme. In vivo treatment of mice with oral lead administration (absorbed dose range: 1-100 micrograms PbAc/kg b.w.) for 1 or 3 months led to a dose-dependent and organ-specific inhibition of the d-ala-d activity. After 3 months of oral lead supply the maximum enzyme inhibition (54%) was found in the bone marrow. At the same time the lowest enzyme inhibition could be seen in the brain which retained 73% of its activity. The erythrocytic and liver enzyme activity was 71% and 72% resp. of the appropriate control. Within 3 weeks after completing the oral lead administration the brain enzyme activity was completely restored. The erythrocytic and liver enzyme activities were still significantly, but not very markedly inhibited, whereas the bone marrow d-ala-d remained seriously depressed. According to these experiments, the lead dose which causes a long term inhibition of the bone marrow and erythrocytic d-ala-d activities is assumed to range between 50 and 100 micrograms PbAc/kg b.w. and day, as an absorbed dose.

Nitrate Reductase Activity in Shoots and Roots of Maize Seedlings as Affected by the Form of Nitrogen Nutrition and the pH of the Nutrient Solution

The effect of nitrogen form (NH(4)-N, NH(4)-N + NO(3) (-), NO(3) (-)) on nitrate reductase activity in roots and shoots of maize (Zea mays L. cv INRA 508) seedlings was studied. Nitrate reductase activity in leaves was consistent with the well known fact that NO(3) (-) increases, and NH(4) (+) and amide-N decrease, nitrate reductase activity. Nitrate reductase activity in the roots, however, could not be explained by the root content of NO(3) (-), NH(4)-N, and amide-N. In roots, nitrate reductase activity in vitro was correlated with the rate of nitrate reduction in vivo. Inasmuch as nitrate reduction results in the production of OH(-) and stimulates the synthesis of organic anions, it was postulated that nitrate reductase activity of roots is stimulated by the released OH(-) or by the synthesized organic anions rather than by nitrate itself. Addition of HCO(3) (-) to nutrient solution of maize seedlings resulted in a significant increase of the nitrate reductase activity in the roots. As HCO(3) (-), like OH(-), increases pH and promotes the synthesis of organic anions, this provides circumstantial evidence that alkaline conditions and/or organic anions have a more direct impact on nitrate reductase activity than do NO(3) (-), NH(4)-N, and amide-N.

The action of azimexone on the cells of the hemopoietic system in mice, especially after damage with X-rays

Mice were exposed to single doses of whole body X-irradiation (1 - 2 - 4 Gy) or were treated with sulphur mustard (15 mg/kg body weight i.p.). This treatment caused a reduction of the pluripotent stem cells in the bone marrow, of the total count of nucleated bone marrow cells in the femora and of the WBC in the peripheral blood. The size distribution of the bone marrow cells showed three separate peaks. From the histological examination of the bone marrow of X-irradiated mice it was deduced that the first peak represents erythrocytes, the second lymphocytes and the third peak the precursors of red and white blood cells. Multiple doses (25 - 50 - 100 mg/kg body weight) of azimexone, an immunomodulating substance, led after moderate doses of X-rays (2 Gy) or sulphur mustard to a more rapid recovery of the various parameters. In particular a stimulant action of azimexone on the pluripotent stem cells of mice not subjected to the injurious agents could also be demonstrated.

Zinc, copper and manganese in the organs of rats after sublethal cyanide intoxication

Single doses of sodium cyanide (60 mumol/kg body weight s.c.) were administered to male Sprague-Dawley rats. The effects of this poison on the content of the trace elements zinc, copper and manganese was investigated in various organs after 30 min, 2 h, 24 h, 48 h and 1 week. The zinc content in the liver was elevated 24 h after this sublethal cyanide dose (by approximately 20%). In contrast, the copper content in the kidneys was lowered (by approximately 15%) at the same time. Almost similar changes were observed in the same organs after daily administration of the poison for 5 days. For comparison, another group of rats was allowed to respire for 30 min the air that contained only 10% oxygen. The above changes in the trace element concentrations were not observed under these conditions. After sublethal cyanide poisoning there seemed be slight but specific alterations in the trace element concentrations in the liver and kidneys of rats. On the other hand, there were no alterations in serum, heart, lung, brain, muscle, bone or testes. Up to now there is no clearcut explanation for the development and the possible biochemical importance of these results.

Interaction between Light Intensity and NaCl Salinity and Their Effects on Growth, CO(2) Assimilation, and Photosynthate Conversion in Young Broad Beans

Seedings of Vicia faba were grown for four weeks at two different light intensities (55 and 105 watts per square meter) in a saline (50 millimolar NaCl) and nonsaline nutrient solution. NaCl salinity depressed growth and restricted protein formation, CO(2) assimilation, and especially the incorporation of photosynthates into the lipid fraction. Conversion of photosynthates in leaves was much more affected by salinity than was photosynthate turnover in roots. The detrimental effect of NaCl salinity on growth, protein formation, and CO(2) assimilation was greater under low than under high light conditions. Plants of the high light intensity treatment were more capable of excluding Na(+) and Cl(-) and accumulating nutrient cation species (Ca(2+), K(+), Mg(2+)) than plants grown under low light intensity. It is suggested that the improved ionic status provided better conditions for protein synthesis, CO(2) assimilation, and especially for the conversion of photosynthates into lipids.

Reduction of acute toxicity of cyclophosphamide and X-rays by the new immunomodulating compound BM 12.531

BM 12.531, the 2-[2-cyanaziridinyl-(1)]-2-[2-carbamoylaziridinyl-(1)]-propane, (prop. INN Azimexon), reduces significantly the acute toxicity of cyclophosphamide and X-rays in rats and mice, respectively. The leucopenia induced by X-rays was partially compensated by BM 12.531 in rats.

Effect of Potassium Supply on the Rate of Phloem Sap Exudation and the Composition of Phloem Sap of Ricinus communis

The composition of phloem sap has been investigated in Ricinus communis var. gibsonii, grown for 2 weeks on nutrient solution of low and high potassium content (K(1) and K(2)). Diagonal cuts were made in the bark of the stem resulting in the exudation of clear droplets which mainly consisted of phloem sap. Although the plants at low K (0.4 mm) and high K (1 mm) did not differ in growth, leaf area, height, or stem circumference, the rate of exudation of the high K plants was about twice as high as that of the plants with the lower K supply. This promoting effect of K on exudation did not result in a dilution of organic (sucrose, UDP-glucose, ATP, UTP) and inorganic constituents of the phloem sap. For the following compounds, even significantly higher concentrations in the exudate were observed in the K(2) plants: potassium, raffinose, glucose 6-phosphate, and fructose 6-phosphate. Also, the osmotic pressure of the phloem sap was substantially increased in the higher K treatment. Experiments in which labeled (14)CO(2) was applied to one leaf showed that K had a favorable effect on the assimilation of CO(2), and in particular promoted the export of photosynthates from the leaf. It is suggested that the higher rate of phloem-loading in the plants with the better K supply is due to the higher CO(2) assimilation rate and especially to a better provision of ATP required for phloem loading. Higher phloem-loading rates result in higher osmotic pressure in the sieve tubes which probably gave rise to the higher flow rates observed in the plants with improved K supply.

The Effect of Potassium on the Fixation of Molecular Nitrogen by Root Nodules of Vicia faba

The effect of potassium supply of Vicia faba on the fixation of molecular nitrogen by root nodules was studied by using (15)N-labeled molecular nitrogen. Plants well supplied with potassium showed higher contents of (15)N in the soluble amino fraction and in the protein fraction of various plant organs as compared with plants of a lower potassium status. This effect was evident particularly in the root nodules. Assimilation experiments, carried out with (14)CO(2), revealed that the content of radioactivity in the sugars and amino acids of the root nodules was increased by the potassium supply of the host plants. In particular, the content of (14)C amino acids in the root nodules was influenced beneficially by potassium, which means that potassium favored the provision of reduced nitrogen (NH(3)). It is postulated that the better carbohydrate supply of nodules, by plants well supplied with potassium, results in a higher carbohydrate turnover in the nodules and thus the provision of ATP and reducing electrons required by the nitrogenase is enhanced.

The Release of Potassium and Sodium from Young Excised Roots of Zea mays under Various Efflux Conditions

The release of potassium and sodium from excised roots of Zea mays having similar contents of potassium and sodium was studied. At low temperature (2 C) the efflux rates of both cations were very similar, but at higher temperature (20 C) the potassium release was reduced considerably, whereas the sodium release was hardly affected. Also, under anaerobic conditions the potassium efflux rate was nearly as high as the sodium efflux rate, but with normal O(2) supply the potassium release was reduced to about one-fifth. Since a changing efflux medium compared with a constant efflux medium had no great influence upon the sodium release but influenced the potassium release very much, it is assumed that the low potassium release under normal metabolic conditions is due to a reabsorption of effluxed potassium from free space. For sodium this reabsorption is of minor significance, as the uptake potential of maize roots for sodium is very poor. It is concluded that the release of potassium and sodium is a diffusion process and that the cell membranes have rather similar diffusivities for these two cations.