Cutane Chloridaufnahme aus hypo-osmotischer Konzentration durch die Chloridzellen von Corixa punctata

Two types of chloride cells are present in the integument of larval and adult corixids both exhibiting fine structural features of ion transporting cells. In adult Corixa punctata the chloride cells are restricted to the legs and front of the head, the latter holding ca. 50% of the total number. Occlusion of the head front with varnish results in a ca. 50% reduction of chloride uptake into the haemolymph when compared with untreated or sham-treated controls. On the other hand, exclusive exposure of the head front (with the mouth and labium sealed) to hypo-osmotic radioactive chloride solution leads to a measurable chloride uptake, whereas exposure of the pronotum, which is free of chloride cells, does not. These complementary results in conjunction with supporting data of chloride histochemistry and autoradiography strongly suggest that the chloride cells are the sites of cutaneous osmoregulatory ion absorption.     

Role of chloride ion as an allosteric activator of angiotensin-converting enzyme

The nature of chloride ion as an activator of angiotensin-converting enzyme was studied by a series of kinetic experiments with hog plasma enzyme preparation. The enzyme required the presence of chloride ion for its full catalytic activity, but its requirement of monovalent anion was not absolute. The K_A value for the enzymechloride binding was estimated to be about 150 mm in all cases regardless of the peptide substrates employed. In the presence of chloride ion, the activity of the enzyme was increased, but its optimum pH was shifted gradually to the alkaline region up to pH 8.2 depending on the concentration of chloride ion. In addition, in the presence of chloride ion, the apparent K_m values were reduced markedly while the V_max values were not much altered; for example, for the hydrolysis of angiotensin I decapeptide, the K_m value decreased by a factor of 50 while only an 18% increase in V_max was observed when the enzyme was saturated with chloride ion. The result suggests that chloride ion acts as a conformational modifier inducing the affinity of synergistic binding of substrate.     

Anti-tumour and pharmacokinetics study of 2-Formyl-8-hydroxy-quinolinium chloride as Galipea longiflora alkaloid analogue

The quinolinium chloride salt of 8-hydroxyqinolinecarbaldehyde (2-Formyl-8-hydroxy-quinolinium chloride) was prepared as Galipea longiflora alkaloid analogue and its anticancer activity was evaluated both in vitro and in vivo. This chloride salt was found to show certain degree of selectivity between hepatoma cells and normal hepatocytes in vitro. Athymic nude mice Hep3B xenograft model further demonstrated that this 2-Formyl-8-hydroxy-quinolinium chloride could execute strong anti-tumour activity with the identification of extensive necrotic feature from the tumour xenograft and limited adverse toxicological effect.     

Rectale Chloridepithelien und osmoregulatorische Salzaufnahme durch den Enddarm von Zygopteren und Anisopteren Libellenlarven

The larvae of Coenagrion puella possess 3, and the larvae of Aeshna cyanea up to 486 rectal chloride epithelia which in both species are organized as transporting epithelia. Combined applications of the histochemical chloride precipitation technique, energy-dispersive micro-analysis of X-rays, autoradiography, and scintillation counting on A. cyanea revealed that the chloride epithelia adsorb chloride from the external solution. By use of radioactive sodium and chloride in hypotonic concentrations applied on normal and anus-sealed larvae it was demonstrated that the rectum of both species is the main pathway for salt uptake into the haemolymph. The stepwise increase in external osmolarity by the addition of mannitol results in a concomitant reduction of chloride uptake into the haemolymph. These results suggest that the rectal chloride epithelia are involved in hyperosmotic regulation by the absorption of salt from the external medium.     

Selective esterification of 1,6-anhydrohexopyranoses: The possible role of intramolecular hydrogen-bonding

Selective esterification reactions of 1,6-anhydro-3-deoxy-β-D-xylo-hexopyranose(1), 1,6-anhydro-β-D-glucopyranose (7), and several derivatives of 7, were conducted with an acid chloride or acid anhydride in pyridine. Reaction of 1 with p-toluenesulfonyl chloride and with benzoyl chloride gave 70 and 63%, respectively, of the 2-esters. The 2-methyl and 2-benzyl ethers of 7, both having strongly hydrogen-bonded C-4 hydroxyl group, reacted with p-toluenesulfonyl chloride to yield the 4-monosulfonates (71 and 74%, respectively). Esterification of the 2-methyl ether and 2-p-toluenesulfonate of 7 with p-toluenesulfonic anhydride instead of with p-toluenesulfonyl chloride led to increased yields of the 4-p-toluenesulfonates after a shorter reaction-time.     

The effect of sodium chloride on enzyme activities from four halophyte species of chenopodiaceae

The in vitro effect of sodium chloride on the enzyme activity of four halophytes, Beta vulgaris ssp. maritima (L.) Thell., Halimione portulacoides (L.) Aell., Salicornia ramosissima Woods and Suaeda maritima (L.) Dum. was investigated. The activity was, in general, affected by sodium chloride in a similar manner to that reported for salt sensitive species. The most notable exceptions were the sodium chloride stimulated ATPases of Beta and Salicornia.     

Lateral transport of ions into the xylem of corn roots: I. Kinetics and energetics

A technique is described for study of the kinetics of lateral transport of ions across single roots of corn, Zea mays, in short term experiments under steady state conditions. The kinetics of chloride transfer to the vessels reflected the kinetics of absorption of chloride by the root cells. Efflux from the root vacuoles contributed to only a small extent to transport of chloride into the exudate. Lateral transport of chloride was inhibited by bromide at chloride concentrations in the ranges of both mechanisms 1 and 2 in a manner implicating competition. The uncoupler carbonylcyanide m-chlorophenylhydrazone used at 1 μm caused transfer of chloride to cease almost immediately at both low and high concentrations of chloride. Oligomycin depressed transport of chloride to the vessels within 10 to 15 minutes after application at 2 micrograms per milliliter. Inhibition by oligomycin was 75% at 0.5 mm chloride and 55% at 5 mm.     

The kinin receptor is expressed in the Malpighian tubule stellate cells in the mosquito Aedes aegypti (L.): a new model needed to explain ion transport?

It is known that insect kinins increase diuresis and fluid secretion in the Aedes aegypti Malpighian tubule, causing a rapid drop of the transepithelial resistance and increasing chloride conductance from the hemolymph towards the tubule lumen. The tubule is composed of both principal and stellate cells. The main route for increased chloride influx upon kinin treatment is proposed to be paracellular, with septate junctions acquiring increased chloride selectivity and conductance. Therefore, kinin treatment renders the Ae. aegypti tubule a “leaky epithelium”, and under this model the kinin receptor is postulated to be expressed in principal cells. However, in another dipteran, the fruit fly Drosophila melanogaster, the main route for chloride transport is transcellular through stellate cells. In both the fruit fly and the mosquito Anopheles stephensi the kinin receptor has been immunolocalized in stellate cells, where it regulates transepithelial chloride permeability. Here we show that in Ae. aegypti, similarly, the stellate cells express the kinin receptor. This was confirmed through immunohistochemistry with two specific anti-kinin receptor antibodies and confocal analysis. The receptor is detected as a 75 kDa band in western blot. These results indicate that the currently accepted model for chloride transport must be re-evaluated in Ae. aegypti and suggest the kinin regulatory signals controlling intercellular junctions originate in the stellate cells.     

A DFT study of the Al2Cl6-catalyzed Friedel–Crafts acylation of phenyl aromatic compounds

The reaction pathways of several Friedel–Crafts acylations involving phenyl aromatic compounds were studied using density functional theory. The reactions were related to the Friedel–Crafts polycondensation of polyaryletherketones. In particular, the acylation of benzene with benzoyl chloride to form benzophenone and variations on this reaction were investigated. The acylation of benzene by one molecule of terephthaloyl chloride or isophthaloyl chloride as well as acylations at the m-, o-, and p-positions of diphenyl ether with one molecule of benzoyl chloride were studied. Adding an additional acyl chloride group to the electrophile appeared to have little influence on the reaction pathway, although the activation energy for the C–C bond-forming steps that occurred when isophthaloyl choride was used was different to the activation energy observed when terephthaloyl chloride was used. Upon changing the nucleophile to diphenyl ether, the reactivity changed according to the trend predicted on based on the o-, p-directing effects of the ether group. The deprotonation step that restored aromaticity varied widely according to the reaction. The rate-determining step in all of the studied reactions was the formation of the acylium ion, followed in importance by either the formation of the Wheland intermediate or the abstraction of hydrogen, depending on the reactivity of the nucleophile.     

Mono- and bis-hydrazone of D-erythrose and 2,3-Dioxo-y-butyrolactone

Aryl-and benzoyl-hydrazones of 2,4-O benzylidene D-erythrose were prepared and acetylated. D-glycero-Tetrulose phenyl-and p-substitute-phenyl-osazones were acylated with acetyl chloride and benzoyl chloride to give the N-acyl-di-O-acyl derivatives, which, on boiling with acetic anhydride, afforded the 1-aryl-3-formylpyrazole N-acetylarylhydrazones. The bis(hydrazones) of 2,3-dioxo-y-butyrolactone are partially hydrolyzed with copper(II) chloride to give the 2-hydrazono-3-oxo-y-butyrolactones, which, on treatment with alkali, rearrange to give the 1-aryl-3-hydroxymethylpyrazoline-4,5-dione 4-arylhydrazones.     

Effect of different salinities on the coniform chloride cells of mayfly larvae

The larvae of Callibaetis coloradensis can tolerate a fairly wide range of salinities at hypotonic concentrations. However, they are more sensitive to increasing than to decreasing salt concentrations. Exposure to isotonic concentration results in profound degenerations of the chloride cells within 1 day. Long-term adaptation to diluted fresh water causes a significant increase in the number of chloride cells, whereas the gradual concentration of fresh water to finally 120 mM sodium chloride within a period of 15 days leads to approximately 50 per cent mortality and significantly reduces the number of chloride cells in the survivors. The same reciprocal relation between the number of chloride cells and the external salinity was found in larvae of C. floridans collected from fresh- and brackish-water habitats. These results suggest that the adaptive behaviour of the chloride cells is correlated with the osmoregulatory situation and enables these animals to live in habitats of different salinities.     

Tamoxifen does not inhibit the swell activated chloride channel in human neutrophils during the respiratory burst

Effective functioning of neutrophils relies upon electron translocation through the NADPH oxidase (NOX). The electron current generated (I_e) by the neutrophil NADPH oxidase is electrogenic and rapidly depolarises the membrane potential in activated human neutrophils. Swelling activated chloride channels have been demonstrated in part to counteract the depolarisation generated by the NADPH oxidase I_e. In the present study, the effects of inhibitors of swell activated chloride channels on ROS production and on the swelling activated chloride conductance was investigated in activated human neutrophils. Tamoxifen (10 μM), a specific inhibitor for swell activated chloride channels in neutrophils, completely inhibited both the PMA and FMLP stimulated respiratory burst. This inhibition of the neutrophil respiratory burst was not due to the blocking effect of tamoxifen on the swelling activated chloride conductance in these cells. These results demonstrate that a tamoxifen insensitive swell activated chloride channel has important significance during the neutrophil respiratory burst.     

Insensitivity to road salt: an advantage for the American bullfrog?

The health of freshwater ecosystems is negatively affected by a multitude of pollutants. In northern latitudes, road deicing agents enter nearby ponds and waterways elevating chloride concentrations in winter and spring. Few studies have examined how amphibians respond to road salt contamination and no study has focused on the response of an invasive amphibian. We examined the effects of NaCl, the most commonly used deicing agent, on the embryos and tadpoles of the American bullfrog, Lithobates catesbeianus, a species that is invasive in many regions around the world. In the first experiment, we exposed L. catesbeianus embryos to ecologically relevant levels of chloride for 60 days. The second experiment examined the indirect consequences of chloride contamination by exposing L. catesbeianus tadpoles to dragonfly larvae. Lithobates catesbeianus did not experience reduced survival, growth, or ability to evade predation in elevated chloride concentrations compared to controls. The lack of a response by L. catesbeianus suggests that its population growth will not be negatively impacted by road salt contamination. This result may be good news for L. catesbeianus, but raises concern for sympatric amphibians that have to contend with negative impacts of both chloride contamination and non-native L. catesbeianus.     

Influence of Incubation Solution on the Rate of Recovery of Pratylenchus brachyurus from Cotton Roots

The rate of recovery of Pratylenchus brachyurus from cotton roots was enhanced when the tissue was incubated in solutions containing 10 ppm ethoxyethyl mercuric chloride, 50 ppm dihydrostreptomycin sulfate, 50, 100, or 1,000 ppm diisobutylphenoxethyl dimethyl benzyl ammonium chloride, or mixtures of these compounds. Incubation in 10 or 100 ppm zinc sulfate, zinc chloride, or magnesium chloride also enhanced the rate of recovery. Incubation solutions containing 1 or 1,000 ppm zinc chloride or magnesium chloride had no influence on this phenomenon, whereas, 10,000 ppm zinc sulfate, zinc chloride, or magnesium chloride retarded the rate of recovery. A t all incubation intervals during the first 21 days after the roots were removed from soil, the P. brachyurus population consisted of approximately 25% second-stage juveniles, 44% third and fourth-stage juveniles, and 31% females. At least 88% of the second-stage juveniles and 51% of the third and fourth-stage juveniles passed through a single 325-mesh sieve, whereas, 84% of the females collected were retained on a sieve of this mesh.     

Medium for Isolation and Differentiation of Vibrio parahaemolyticus and Vibrio alginolyticus

Trypticase soy agar supplemented with sucrose, sodium chloride, bile salts, and triphenyltetrazolium chloride is an improved plating medium for the isolation of Vibrio parahaemolyticus from samples of seawater, permitting better differentiation of this organism from Vibrio alginolyticus and other bacteria.     

Anion Permeability of Frog Skeletal Muscle

Unidirectional chloride effluxes from small bundles of muscle fibers were measured under equilibrium conditions. It was found that chloride effluxes are described by the constant field theory with a chloride permeability constant, P_cl, which is independent of the chloride concentration and the membrane potential. The value of P_cl at neutral pH was found to be 5 x 10^-6 cm/sec. Chloride movements were markedly depressed at low pH and increased at high pH. It is concluded that chloride fluxes are independent of each other over a wide pH range. The effect of nitrate on the chloride effluxes was measured. It was found that both external and internal nitrate alone reduced the chloride efflux with the external nitrate appearing more effective than internal nitrate due to the nonequilibrium nature of the experimental conditions. Under equilibrium conditions the reduction of the chloride efflux by nitrate was greater than the external nitrate effect, both of which were dependent on the relative proportion of nitrate in the bathing solution. These results are consistent with the hypothesis that the inhibition of the chloride movements by nitrate is essentially symmetrical with regard to the inside and outside surfaces of the muscle membranes. The relative action of nitrate on the chloride efflux was independent of the external pH despite marked changes in the absolute values of the fluxes measured.     

Effect of selected mercurials on glyceraldehyde-3-phosphate-dehydrogenase in Pteronarcys californica

Glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was extracted from Pteronarcys californica (Plecoptera) by ammonium sulphate fractionation. The enzyme was treated with three forms of mercury (mercuric chloride, methylmercuric chloride, and phenylmercuric chloride) and their in vitro and in vivo effects on GAPDH were studied. It was found that the orders of toxicity were reversed in the in vivo-in vitro experiments. Electrophoresis was conducted on both treated and untreated enzyme, and showed no differences in mobilities between the two. The enzyme was not found to be inhibited by 0·1 mM iodoacetic acid and required cysteine for activity.     

Differential Effects of Lithium Chloride on In Vitro Growth of Clavibacter michiganense subsp. nebraskense Depending upon Inoculum Source

The bacterium Clavibacter michiganense subsp. nebraskense (Corynebacterium michiganense subsp. nebraskense) was grown in broth cultures and inoculated into corn plants. The plating efficiency of cells from broth cultures was essentially the same on nutrient broth-yeast extract and the semiselective medium for this bacterium, CNS. However, when cells were isolated from Goss bacterial wilt- and blight-infected corn, very few were recovered on CNS compared with the amount recovered on nutrient broth-yeast extract agar. When lithium chloride was omitted from the CNS, recoveries from infected corn were nearly the same as on nutrient broth-yeast extract agar. No other ingredient of CNS was inhibitory, nor did substitution of other salts for lithium chloride cause equal inhibition. The amount of inhibition was proportional to lithium chloride concentration. The inhibition by lithium chloride occurred with several strains of the bacterium isolated from one corn cultivar and with one of the strains recovered from three different cultivars of infected corn.     

Halobacterium volcanii spec. nov., a Dead Sea halobacterium with a moderate salt requirement

A halophilic bacterium was isolated from bottom sediment from the Dead Sea. The organism possessed the properties of the halobacteria, but differed from the known species in two important respects, 1) the cells were disc-shaped and often cupped when grown under optimum conditions, 2) the optimum requirements for sodium chloride was in the range 1.7–2.5 molar which is about half of that generally reported for the halobacteria. The organism was assigned to the genus Halobacterium and described as Halobacterium volcanii spec.nov. The optimum sodium chloride concentration for growth was close to that found in the Dead Sea. The tolerance for magnesium chloride was very high; the organism grew well in media containing magnesium chloride in the concentrations found in the Dead Sea. Halobacterium volcanii is therefore remarkably well fitted for life in the Dead Sea.     

N-methyl-2-anilino-6-naphthalenesulfonyl hydrazine (2,6-mansyl hydrazine): A new sensitive fluorometric reagent for carbonyl compounds

An almost quantitative synthesis of N-methyl-2-anilino-6-naphthalenesulfonyl hydrazine (2,6-mansyl hydrazine) from sulfonyl chloride and hydrazinlum hydroxide is described. The 2,6-mansyl chloride was prepared by different methods from 6-hydroxynaphthalene-2-sulfonic acid (overall yield: 69%). The N- and the O-mansylation of suitable compounds (e.g., amines, amino acids, and phenolic steroids) with 2,6-mansyl chloride and the preparation of oxosteroid-2,6-mansyl hydrazones are deseribed, and the derivatives obtained, their uv spectra, and methods for their thin-layer chromatographic separation are compared with the corresponding data for dansylated compounds.